diff --git a/mongoose/mongoose.c b/mongoose/mongoose.c
index 83d8fe18..3fc0e14a 100644
--- a/mongoose/mongoose.c
+++ b/mongoose/mongoose.c
@@ -1,5 +1,5 @@
 // Copyright (c) 2004-2013 Sergey Lyubka
-// Copyright (c) 2013-2022 Cesanta Software Limited
+// Copyright (c) 2013-2024 Cesanta Software Limited
 // All rights reserved
 //
 // This software is dual-licensed: you can redistribute it and/or modify
@@ -15,7 +15,7 @@
 // Alternatively, you can license this software under a commercial
 // license, as set out in https://www.mongoose.ws/licensing/
 //
-// SPDX-License-Identifier: GPL-2.0-only
+// SPDX-License-Identifier: GPL-2.0-only or commercial
 
 #include "mongoose.h"
 
@@ -24,8 +24,7 @@
 #endif
 
 
-
-static int mg_b64idx(int c) {
+static int mg_base64_encode_single(int c) {
   if (c < 26) {
     return c + 'A';
   } else if (c < 52) {
@@ -37,7 +36,7 @@ static int mg_b64idx(int c) {
   }
 }
 
-static int mg_b64rev(int c) {
+static int mg_base64_decode_single(int c) {
   if (c >= 'A' && c <= 'Z') {
     return c - 'A';
   } else if (c >= 'a' && c <= 'z') {
@@ -55,24 +54,24 @@ static int mg_b64rev(int c) {
   }
 }
 
-int mg_base64_update(unsigned char ch, char *to, int n) {
-  int rem = (n & 3) % 3;
+size_t mg_base64_update(unsigned char ch, char *to, size_t n) {
+  unsigned long rem = (n & 3) % 3;
   if (rem == 0) {
-    to[n] = (char) mg_b64idx(ch >> 2);
+    to[n] = (char) mg_base64_encode_single(ch >> 2);
     to[++n] = (char) ((ch & 3) << 4);
   } else if (rem == 1) {
-    to[n] = (char) mg_b64idx(to[n] | (ch >> 4));
+    to[n] = (char) mg_base64_encode_single(to[n] | (ch >> 4));
     to[++n] = (char) ((ch & 15) << 2);
   } else {
-    to[n] = (char) mg_b64idx(to[n] | (ch >> 6));
-    to[++n] = (char) mg_b64idx(ch & 63);
+    to[n] = (char) mg_base64_encode_single(to[n] | (ch >> 6));
+    to[++n] = (char) mg_base64_encode_single(ch & 63);
     n++;
   }
   return n;
 }
 
-int mg_base64_final(char *to, int n) {
-  int saved = n;
+size_t mg_base64_final(char *to, size_t n) {
+  size_t saved = n;
   // printf("---[%.*s]\n", n, to);
   if (n & 3) n = mg_base64_update(0, to, n);
   if ((saved & 3) == 2) n--;
@@ -82,20 +81,27 @@ int mg_base64_final(char *to, int n) {
   return n;
 }
 
-int mg_base64_encode(const unsigned char *p, int n, char *to) {
-  int i, len = 0;
+size_t mg_base64_encode(const unsigned char *p, size_t n, char *to, size_t dl) {
+  size_t i, len = 0;
+  if (dl > 0) to[0] = '\0';
+  if (dl < ((n / 3) + (n % 3 ? 1 : 0)) * 4 + 1) return 0;
   for (i = 0; i < n; i++) len = mg_base64_update(p[i], to, len);
   len = mg_base64_final(to, len);
   return len;
 }
 
-int mg_base64_decode(const char *src, int n, char *dst) {
+size_t mg_base64_decode(const char *src, size_t n, char *dst, size_t dl) {
   const char *end = src == NULL ? NULL : src + n;  // Cannot add to NULL
-  int len = 0;
+  size_t len = 0;
+  if (dl < n / 4 * 3 + 1) goto fail;
   while (src != NULL && src + 3 < end) {
-    int a = mg_b64rev(src[0]), b = mg_b64rev(src[1]), c = mg_b64rev(src[2]),
-        d = mg_b64rev(src[3]);
-    if (a == 64 || a < 0 || b == 64 || b < 0 || c < 0 || d < 0) return 0;
+    int a = mg_base64_decode_single(src[0]),
+        b = mg_base64_decode_single(src[1]),
+        c = mg_base64_decode_single(src[2]),
+        d = mg_base64_decode_single(src[3]);
+    if (a == 64 || a < 0 || b == 64 || b < 0 || c < 0 || d < 0) {
+      goto fail;
+    }
     dst[len++] = (char) ((a << 2) | (b >> 4));
     if (src[2] != '=') {
       dst[len++] = (char) ((b << 4) | (c >> 2));
@@ -105,1942 +111,2915 @@ int mg_base64_decode(const char *src, int n, char *dst) {
   }
   dst[len] = '\0';
   return len;
+fail:
+  if (dl > 0) dst[0] = '\0';
+  return 0;
 }
 
 #ifdef MG_ENABLE_LINES
-#line 1 "src/dns.c"
+#line 1 "src/device_ch32v307.c"
 #endif
 
 
 
+#if MG_DEVICE == MG_DEVICE_CH32V307
+// RM: https://www.wch-ic.com/downloads/CH32FV2x_V3xRM_PDF.html
 
+#define FLASH_BASE 0x40022000
+#define FLASH_ACTLR (FLASH_BASE + 0)
+#define FLASH_KEYR (FLASH_BASE + 4)
+#define FLASH_OBKEYR (FLASH_BASE + 8)
+#define FLASH_STATR (FLASH_BASE + 12)
+#define FLASH_CTLR (FLASH_BASE + 16)
+#define FLASH_ADDR (FLASH_BASE + 20)
+#define FLASH_OBR (FLASH_BASE + 28)
+#define FLASH_WPR (FLASH_BASE + 32)
 
-
-
-struct dns_data {
-  struct dns_data *next;
-  struct mg_connection *c;
-  uint64_t expire;
-  uint16_t txnid;
-};
-
-static void mg_sendnsreq(struct mg_connection *, struct mg_str *, int,
-                         struct mg_dns *, bool);
-
-static void mg_dns_free(struct mg_connection *c, struct dns_data *d) {
-  LIST_DELETE(struct dns_data,
-              (struct dns_data **) &c->mgr->active_dns_requests, d);
-  free(d);
+void *mg_flash_start(void) {
+  return (void *) 0x08000000;
 }
-
-void mg_resolve_cancel(struct mg_connection *c) {
-  struct dns_data *tmp, *d = (struct dns_data *) c->mgr->active_dns_requests;
-  for (; d != NULL; d = tmp) {
-    tmp = d->next;
-    if (d->c == c) mg_dns_free(c, d);
+size_t mg_flash_size(void) {
+  return 480 * 1024;  // First 320k is 0-wait
+}
+size_t mg_flash_sector_size(void) {
+  return 4096;
+}
+size_t mg_flash_write_align(void) {
+  return 4;
+}
+int mg_flash_bank(void) {
+  return 0;
+}
+void mg_device_reset(void) {
+  *((volatile uint32_t *) 0xbeef0000) |= 1U << 7;  // NVIC_SystemReset()
+}
+static void flash_unlock(void) {
+  static bool unlocked;
+  if (unlocked == false) {
+    MG_REG(FLASH_KEYR) = 0x45670123;
+    MG_REG(FLASH_KEYR) = 0xcdef89ab;
+    unlocked = true;
   }
 }
+static void flash_wait(void) {
+  while (MG_REG(FLASH_STATR) & MG_BIT(0)) (void) 0;
+}
 
-static size_t mg_dns_parse_name_depth(const uint8_t *s, size_t len, size_t ofs,
-                                      char *to, size_t tolen, size_t j,
-                                      int depth) {
-  size_t i = 0;
-  if (tolen > 0 && depth == 0) to[0] = '\0';
-  if (depth > 5) return 0;
-  // MG_INFO(("ofs %lx %x %x", (unsigned long) ofs, s[ofs], s[ofs + 1]));
-  while (ofs + i + 1 < len) {
-    size_t n = s[ofs + i];
-    if (n == 0) {
-      i++;
-      break;
-    }
-    if (n & 0xc0) {
-      size_t ptr = (((n & 0x3f) << 8) | s[ofs + i + 1]);  // 12 is hdr len
-      // MG_INFO(("PTR %lx", (unsigned long) ptr));
-      if (ptr + 1 < len && (s[ptr] & 0xc0) == 0 &&
-          mg_dns_parse_name_depth(s, len, ptr, to, tolen, j, depth + 1) == 0)
-        return 0;
-      i += 2;
-      break;
-    }
-    if (ofs + i + n + 1 >= len) return 0;
-    if (j > 0) {
-      if (j < tolen) to[j] = '.';
-      j++;
-    }
-    if (j + n < tolen) memcpy(&to[j], &s[ofs + i + 1], n);
-    j += n;
-    i += n + 1;
-    if (j < tolen) to[j] = '\0';  // Zero-terminate this chunk
-    // MG_INFO(("--> [%s]", to));
-  }
-  if (tolen > 0) to[tolen - 1] = '\0';  // Make sure make sure it is nul-term
-  return i;
+bool mg_flash_erase(void *addr) {
+  //MG_INFO(("%p", addr));
+  flash_unlock();
+  flash_wait();
+  MG_REG(FLASH_ADDR) = (uint32_t) addr;
+  MG_REG(FLASH_CTLR) |= MG_BIT(1) | MG_BIT(6);  // PER | STRT;
+  flash_wait();
+  return true;
 }
 
-static size_t mg_dns_parse_name(const uint8_t *s, size_t n, size_t ofs,
-                                char *dst, size_t dstlen) {
-  return mg_dns_parse_name_depth(s, n, ofs, dst, dstlen, 0, 0);
+static bool is_page_boundary(const void *addr) {
+  uint32_t val = (uint32_t) addr;
+  return (val & (mg_flash_sector_size() - 1)) == 0;
 }
 
-size_t mg_dns_parse_rr(const uint8_t *buf, size_t len, size_t ofs,
-                       bool is_question, struct mg_dns_rr *rr) {
-  const uint8_t *s = buf + ofs, *e = &buf[len];
+bool mg_flash_write(void *addr, const void *buf, size_t len) {
+  //MG_INFO(("%p %p %lu", addr, buf, len));
+  //mg_hexdump(buf, len);
+  flash_unlock();
+  const uint16_t *src = (uint16_t *) buf, *end = &src[len / 2];
+  uint16_t *dst = (uint16_t *) addr;
+  MG_REG(FLASH_CTLR) |= MG_BIT(0);  // Set PG
+  //MG_INFO(("CTLR: %#lx", MG_REG(FLASH_CTLR)));
+  while (src < end) {
+    if (is_page_boundary(dst)) mg_flash_erase(dst);
+    *dst++ = *src++;
+    flash_wait();
+  }
+  MG_REG(FLASH_CTLR) &= ~MG_BIT(0);  // Clear PG
+  return true;
+}
+#endif
 
-  memset(rr, 0, sizeof(*rr));
-  if (len < sizeof(struct mg_dns_header)) return 0;  // Too small
-  if (len > 512) return 0;  //  Too large, we don't expect that
-  if (s >= e) return 0;     //  Overflow
+#ifdef MG_ENABLE_LINES
+#line 1 "src/device_dummy.c"
+#endif
 
-  if ((rr->nlen = (uint16_t) mg_dns_parse_name(buf, len, ofs, NULL, 0)) == 0)
-    return 0;
-  s += rr->nlen + 4;
-  if (s > e) return 0;
-  rr->atype = (uint16_t) (((uint16_t) s[-4] << 8) | s[-3]);
-  rr->aclass = (uint16_t) (((uint16_t) s[-2] << 8) | s[-1]);
-  if (is_question) return (size_t) (rr->nlen + 4);
 
-  s += 6;
-  if (s > e) return 0;
-  rr->alen = (uint16_t) (((uint16_t) s[-2] << 8) | s[-1]);
-  if (s + rr->alen > e) return 0;
-  return (size_t) (rr->nlen + rr->alen + 10);
+#if MG_DEVICE == MG_DEVICE_NONE
+void *mg_flash_start(void) {
+  return NULL;
+}
+size_t mg_flash_size(void) {
+  return 0;
+}
+size_t mg_flash_sector_size(void) {
+  return 0;
+}
+size_t mg_flash_write_align(void) {
+  return 0;
+}
+int mg_flash_bank(void) {
+  return 0;
+}
+bool mg_flash_erase(void *location) {
+  (void) location;
+  return false;
+}
+bool mg_flash_swap_bank(void) {
+  return true;
+}
+bool mg_flash_write(void *addr, const void *buf, size_t len) {
+  (void) addr, (void) buf, (void) len;
+  return false;
+}
+void mg_device_reset(void) {
 }
+#endif
 
-bool mg_dns_parse(const uint8_t *buf, size_t len, struct mg_dns_message *dm) {
-  const struct mg_dns_header *h = (struct mg_dns_header *) buf;
-  struct mg_dns_rr rr;
-  size_t i, n, ofs = sizeof(*h);
-  memset(dm, 0, sizeof(*dm));
+#ifdef MG_ENABLE_LINES
+#line 1 "src/device_flash.c"
+#endif
 
-  if (len < sizeof(*h)) return 0;                // Too small, headers dont fit
-  if (mg_ntohs(h->num_questions) > 1) return 0;  // Sanity
-  if (mg_ntohs(h->num_answers) > 10) return 0;   // Sanity
-  dm->txnid = mg_ntohs(h->txnid);
 
-  for (i = 0; i < mg_ntohs(h->num_questions); i++) {
-    if ((n = mg_dns_parse_rr(buf, len, ofs, true, &rr)) == 0) return false;
-    // MG_INFO(("Q %lu %lu %hu/%hu", ofs, n, rr.atype, rr.aclass));
-    ofs += n;
+#if MG_DEVICE == MG_DEVICE_STM32H7 || MG_DEVICE == MG_DEVICE_STM32H5 || \
+    MG_DEVICE == MG_DEVICE_RT1020 || MG_DEVICE == MG_DEVICE_RT1060
+// Flash can be written only if it is erased. Erased flash is 0xff (all bits 1)
+// Writes must be mg_flash_write_align() - aligned. Thus if we want to save an
+// object, we pad it at the end for alignment.
+//
+// Objects in the flash sector are stored sequentially:
+// | 32-bit size | 32-bit KEY | ..data.. | ..pad.. | 32-bit size | ......
+//
+// In order to get to the next object, read its size, then align up.
+
+// Traverse the list of saved objects
+size_t mg_flash_next(char *p, char *end, uint32_t *key, size_t *size) {
+  size_t aligned_size = 0, align = mg_flash_write_align(), left = end - p;
+  uint32_t *p32 = (uint32_t *) p, min_size = sizeof(uint32_t) * 2;
+  if (p32[0] != 0xffffffff && left > MG_ROUND_UP(min_size, align)) {
+    if (size) *size = (size_t) p32[0];
+    if (key) *key = p32[1];
+    aligned_size = MG_ROUND_UP(p32[0] + sizeof(uint32_t) * 2, align);
+    if (left < aligned_size) aligned_size = 0;  // Out of bounds, fail
   }
-  for (i = 0; i < mg_ntohs(h->num_answers); i++) {
-    if ((n = mg_dns_parse_rr(buf, len, ofs, false, &rr)) == 0) return false;
-    // MG_INFO(("A -- %lu %lu %hu/%hu %s", ofs, n, rr.atype, rr.aclass,
-    // dm->name));
-    mg_dns_parse_name(buf, len, ofs, dm->name, sizeof(dm->name));
-    ofs += n;
-
-    if (rr.alen == 4 && rr.atype == 1 && rr.aclass == 1) {
-      dm->addr.is_ip6 = false;
-      memcpy(&dm->addr.ip, &buf[ofs - 4], 4);
-      dm->resolved = true;
-      break;  // Return success
-    } else if (rr.alen == 16 && rr.atype == 28 && rr.aclass == 1) {
-      dm->addr.is_ip6 = true;
-      memcpy(&dm->addr.ip6, &buf[ofs - 16], 16);
-      dm->resolved = true;
-      break;  // Return success
+  return aligned_size;
+}
+
+// Return the last sector of Bank 2
+static char *flash_last_sector(void) {
+  size_t ss = mg_flash_sector_size(), size = mg_flash_size();
+  char *base = (char *) mg_flash_start(), *last = base + size - ss;
+  if (mg_flash_bank() == 2) last -= size / 2;
+  return last;
+}
+
+// Find a saved object with a given key
+bool mg_flash_load(void *sector, uint32_t key, void *buf, size_t len) {
+  char *base = (char *) mg_flash_start(), *s = (char *) sector, *res = NULL;
+  size_t ss = mg_flash_sector_size(), ofs = 0, n, sz;
+  bool ok = false;
+  if (s == NULL) s = flash_last_sector();
+  if (s < base || s >= base + mg_flash_size()) {
+    MG_ERROR(("%p is outsize of flash", sector));
+  } else if (((s - base) % ss) != 0) {
+    MG_ERROR(("%p is not a sector boundary", sector));
+  } else {
+    uint32_t k, scanned = 0;
+    while ((n = mg_flash_next(s + ofs, s + ss, &k, &sz)) > 0) {
+      // MG_DEBUG((" > obj %lu, ofs %lu, key %x/%x", scanned, ofs, k, key));
+      // mg_hexdump(s + ofs, n);
+      if (k == key && sz == len) {
+        res = s + ofs + sizeof(uint32_t) * 2;
+        memcpy(buf, res, len);  // Copy object
+        ok = true;              // Keep scanning for the newer versions of it
+      }
+      ofs += n, scanned++;
     }
+    MG_DEBUG(("Scanned %u objects, key %x is @ %p", scanned, key, res));
   }
-  return true;
+  return ok;
 }
 
-static void dns_cb(struct mg_connection *c, int ev, void *ev_data,
-                   void *fn_data) {
-  struct dns_data *d, *tmp;
-  if (ev == MG_EV_POLL) {
-    uint64_t now = *(uint64_t *) ev_data;
-    for (d = (struct dns_data *) c->mgr->active_dns_requests; d != NULL;
-         d = tmp) {
-      tmp = d->next;
-      // MG_DEBUG ("%lu %lu dns poll", d->expire, now));
-      if (now > d->expire) mg_error(d->c, "DNS timeout");
+// For all saved objects in the sector, delete old versions of objects
+static void mg_flash_sector_cleanup(char *sector) {
+  // Buffer all saved objects into an IO buffer (backed by RAM)
+  // erase sector, and re-save them.
+  struct mg_iobuf io = {0, 0, 0, 2048};
+  size_t ss = mg_flash_sector_size();
+  size_t n, size, size2, ofs = 0, hs = sizeof(uint32_t) * 2;
+  uint32_t key;
+  // Traverse all objects
+  MG_DEBUG(("Cleaning up sector %p", sector));
+  while ((n = mg_flash_next(sector + ofs, sector + ss, &key, &size)) > 0) {
+    // Delete an old copy of this object in the cache
+    for (size_t o = 0; o < io.len; o += size2 + hs) {
+      uint32_t k = *(uint32_t *) (io.buf + o + sizeof(uint32_t));
+      size2 = *(uint32_t *) (io.buf + o);
+      if (k == key) {
+        mg_iobuf_del(&io, o, size2 + hs);
+        break;
+      }
     }
-  } else if (ev == MG_EV_READ) {
-    struct mg_dns_message dm;
-    int resolved = 0;
-    if (mg_dns_parse(c->recv.buf, c->recv.len, &dm) == false) {
-      MG_ERROR(("Unexpected DNS response:"));
-      mg_hexdump(c->recv.buf, c->recv.len);
-    } else {
-      // MG_VERBOSE(("%s %d", dm.name, dm.resolved));
-      for (d = (struct dns_data *) c->mgr->active_dns_requests; d != NULL;
-           d = tmp) {
-        tmp = d->next;
-        // MG_INFO(("d %p %hu %hu", d, d->txnid, dm.txnid));
-        if (dm.txnid != d->txnid) continue;
-        if (d->c->is_resolving) {
-          if (dm.resolved) {
-            dm.addr.port = d->c->rem.port;  // Save port
-            d->c->rem = dm.addr;            // Copy resolved address
-            MG_DEBUG(
-                ("%lu %s is %I", d->c->id, dm.name, d->c->rem.is_ip6 ? 16 : 4,
-                 d->c->rem.is_ip6 ? &d->c->rem.ip6 : (void *) &d->c->rem.ip));
-            mg_connect_resolved(d->c);
-#if MG_ENABLE_IPV6
-          } else if (dm.addr.is_ip6 == false && dm.name[0] != '\0' &&
-                     c->mgr->use_dns6 == false) {
-            struct mg_str x = mg_str(dm.name);
-            mg_sendnsreq(d->c, &x, c->mgr->dnstimeout, &c->mgr->dns6, true);
-#endif
-          } else {
-            mg_error(d->c, "%s DNS lookup failed", dm.name);
+    // And add the new copy
+    mg_iobuf_add(&io, io.len, sector + ofs, size + hs);
+    ofs += n;
+  }
+  // All objects are cached in RAM now
+  if (mg_flash_erase(sector)) {  // Erase sector. If successful,
+    for (ofs = 0; ofs < io.len; ofs += size + hs) {  // Traverse cached objects
+      size = *(uint32_t *) (io.buf + ofs);
+      key = *(uint32_t *) (io.buf + ofs + sizeof(uint32_t));
+      mg_flash_save(sector, key, io.buf + ofs + hs, size);  // Save to flash
+    }
+  }
+  mg_iobuf_free(&io);
+}
+
+// Save an object with a given key - append to the end of an object list
+bool mg_flash_save(void *sector, uint32_t key, const void *buf, size_t len) {
+  char *base = (char *) mg_flash_start(), *s = (char *) sector;
+  size_t ss = mg_flash_sector_size(), ofs = 0, n;
+  bool ok = false;
+  if (s == NULL) s = flash_last_sector();
+  if (s < base || s >= base + mg_flash_size()) {
+    MG_ERROR(("%p is outsize of flash", sector));
+  } else if (((s - base) % ss) != 0) {
+    MG_ERROR(("%p is not a sector boundary", sector));
+  } else {
+    char ab[mg_flash_write_align()];  // Aligned write block
+    uint32_t hdr[2] = {(uint32_t) len, key};
+    size_t needed = sizeof(hdr) + len;
+    size_t needed_aligned = MG_ROUND_UP(needed, sizeof(ab));
+    while ((n = mg_flash_next(s + ofs, s + ss, NULL, NULL)) > 0) ofs += n;
+
+    // If there is not enough space left, cleanup sector and re-eval ofs
+    if (ofs + needed_aligned >= ss) {
+      mg_flash_sector_cleanup(s);
+      ofs = 0;
+      while ((n = mg_flash_next(s + ofs, s + ss, NULL, NULL)) > 0) ofs += n;
+    }
+
+    if (ofs + needed_aligned <= ss) {
+      // Enough space to save this object
+      if (sizeof(ab) < sizeof(hdr)) {
+        // Flash write granularity is 32 bit or less, write with no buffering
+        ok = mg_flash_write(s + ofs, hdr, sizeof(hdr));
+        if (ok) mg_flash_write(s + ofs + sizeof(hdr), buf, len);
+      } else {
+        // Flash granularity is sizeof(hdr) or more. We need to save in
+        // 3 chunks: initial block, bulk, rest. This is because we have
+        // two memory chunks to write: hdr and buf, on aligned boundaries.
+        n = sizeof(ab) - sizeof(hdr);      // Initial chunk that we write
+        if (n > len) n = len;              // is
+        memset(ab, 0xff, sizeof(ab));      // initialized to all-one
+        memcpy(ab, hdr, sizeof(hdr));      // contains the header (key + size)
+        memcpy(ab + sizeof(hdr), buf, n);  // and an initial part of buf
+        MG_INFO(("saving initial block of %lu", sizeof(ab)));
+        ok = mg_flash_write(s + ofs, ab, sizeof(ab));
+        if (ok && len > n) {
+          size_t n2 = MG_ROUND_DOWN(len - n, sizeof(ab));
+          if (n2 > 0) {
+            MG_INFO(("saving bulk, %lu", n2));
+            ok = mg_flash_write(s + ofs + sizeof(ab), (char *) buf + n, n2);
+          }
+          if (ok && len > n) {
+            size_t n3 = len - n - n2;
+            if (n3 > sizeof(ab)) n3 = sizeof(ab);
+            memset(ab, 0xff, sizeof(ab));
+            memcpy(ab, (char *) buf + n + n2, n3);
+            MG_INFO(("saving rest, %lu", n3));
+            ok = mg_flash_write(s + ofs + sizeof(ab) + n2, ab, sizeof(ab));
           }
-        } else {
-          MG_ERROR(("%lu already resolved", d->c->id));
         }
-        mg_dns_free(c, d);
-        resolved = 1;
       }
-    }
-    if (!resolved) MG_ERROR(("stray DNS reply"));
-    c->recv.len = 0;
-  } else if (ev == MG_EV_CLOSE) {
-    for (d = (struct dns_data *) c->mgr->active_dns_requests; d != NULL;
-         d = tmp) {
-      tmp = d->next;
-      mg_error(d->c, "DNS error");
-      mg_dns_free(c, d);
+      MG_DEBUG(("Saved %lu/%lu bytes @ %p, key %x: %d", len, needed_aligned,
+                s + ofs, key, ok));
+      MG_DEBUG(("Sector space left: %lu bytes", ss - ofs - needed_aligned));
+    } else {
+      MG_ERROR(("Sector is full"));
     }
   }
-  (void) fn_data;
+  return ok;
+}
+#else
+bool mg_flash_save(void *sector, uint32_t key, const void *buf, size_t len) {
+  (void) sector, (void) key, (void) buf, (void) len;
+  return false;
+}
+bool mg_flash_load(void *sector, uint32_t key, void *buf, size_t len) {
+  (void) sector, (void) key, (void) buf, (void) len;
+  return false;
 }
+#endif
 
-static bool mg_dns_send(struct mg_connection *c, const struct mg_str *name,
-                        uint16_t txnid, bool ipv6) {
-  struct {
-    struct mg_dns_header header;
-    uint8_t data[256];
-  } pkt;
-  size_t i, n;
-  memset(&pkt, 0, sizeof(pkt));
-  pkt.header.txnid = mg_htons(txnid);
-  pkt.header.flags = mg_htons(0x100);
-  pkt.header.num_questions = mg_htons(1);
-  for (i = n = 0; i < sizeof(pkt.data) - 5; i++) {
-    if (name->ptr[i] == '.' || i >= name->len) {
-      pkt.data[n] = (uint8_t) (i - n);
-      memcpy(&pkt.data[n + 1], name->ptr + n, i - n);
-      n = i + 1;
-    }
-    if (i >= name->len) break;
+#ifdef MG_ENABLE_LINES
+#line 1 "src/device_imxrt.c"
+#endif
+
+
+
+#if MG_DEVICE == MG_DEVICE_RT1020 || MG_DEVICE == MG_DEVICE_RT1060
+
+struct mg_flexspi_lut_seq {
+  uint8_t seqNum;
+  uint8_t seqId;
+  uint16_t reserved;
+};
+
+struct mg_flexspi_mem_config {
+  uint32_t tag;
+  uint32_t version;
+  uint32_t reserved0;
+  uint8_t readSampleClkSrc;
+  uint8_t csHoldTime;
+  uint8_t csSetupTime;
+  uint8_t columnAddressWidth;
+  uint8_t deviceModeCfgEnable;
+  uint8_t deviceModeType;
+  uint16_t waitTimeCfgCommands;
+  struct mg_flexspi_lut_seq deviceModeSeq;
+  uint32_t deviceModeArg;
+  uint8_t configCmdEnable;
+  uint8_t configModeType[3];
+  struct mg_flexspi_lut_seq configCmdSeqs[3];
+  uint32_t reserved1;
+  uint32_t configCmdArgs[3];
+  uint32_t reserved2;
+  uint32_t controllerMiscOption;
+  uint8_t deviceType;
+  uint8_t sflashPadType;
+  uint8_t serialClkFreq;
+  uint8_t lutCustomSeqEnable;
+  uint32_t reserved3[2];
+  uint32_t sflashA1Size;
+  uint32_t sflashA2Size;
+  uint32_t sflashB1Size;
+  uint32_t sflashB2Size;
+  uint32_t csPadSettingOverride;
+  uint32_t sclkPadSettingOverride;
+  uint32_t dataPadSettingOverride;
+  uint32_t dqsPadSettingOverride;
+  uint32_t timeoutInMs;
+  uint32_t commandInterval;
+  uint16_t dataValidTime[2];
+  uint16_t busyOffset;
+  uint16_t busyBitPolarity;
+  uint32_t lookupTable[64];
+  struct mg_flexspi_lut_seq lutCustomSeq[12];
+  uint32_t reserved4[4];
+};
+
+struct mg_flexspi_nor_config {
+  struct mg_flexspi_mem_config memConfig;
+  uint32_t pageSize;
+  uint32_t sectorSize;
+  uint8_t ipcmdSerialClkFreq;
+  uint8_t isUniformBlockSize;
+  uint8_t reserved0[2];
+  uint8_t serialNorType;
+  uint8_t needExitNoCmdMode;
+  uint8_t halfClkForNonReadCmd;
+  uint8_t needRestoreNoCmdMode;
+  uint32_t blockSize;
+  uint32_t reserve2[11];
+};
+
+/* FLEXSPI memory config block related defintions */
+#define MG_FLEXSPI_CFG_BLK_TAG (0x42464346UL)      // ascii "FCFB" Big Endian
+#define MG_FLEXSPI_CFG_BLK_VERSION (0x56010400UL)  // V1.4.0
+
+#define MG_FLEXSPI_LUT_SEQ(cmd0, pad0, op0, cmd1, pad1, op1)                                      \
+  (MG_FLEXSPI_LUT_OPERAND0(op0) | MG_FLEXSPI_LUT_NUM_PADS0(pad0) | MG_FLEXSPI_LUT_OPCODE0(cmd0) | \
+   MG_FLEXSPI_LUT_OPERAND1(op1) | MG_FLEXSPI_LUT_NUM_PADS1(pad1) | MG_FLEXSPI_LUT_OPCODE1(cmd1))
+
+#define MG_CMD_SDR 0x01
+#define MG_CMD_DDR 0x21
+#define MG_DUMMY_SDR 0x0C
+#define MG_DUMMY_DDR 0x2C
+#define MG_RADDR_SDR 0x02
+#define MG_RADDR_DDR 0x22
+#define MG_READ_SDR 0x09
+#define MG_READ_DDR 0x29
+#define MG_WRITE_SDR 0x08
+#define MG_WRITE_DDR 0x28
+#define MG_STOP 0
+
+#define MG_FLEXSPI_1PAD 0
+#define MG_FLEXSPI_2PAD 1
+#define MG_FLEXSPI_4PAD 2
+#define MG_FLEXSPI_8PAD 3
+
+#define MG_FLEXSPI_QSPI_LUT                                                                        \
+  {                                                                                                \
+    [0] = MG_FLEXSPI_LUT_SEQ(MG_CMD_SDR, MG_FLEXSPI_1PAD, 0xEB, MG_RADDR_SDR, MG_FLEXSPI_4PAD,     \
+                             0x18),                                                                \
+    [1] = MG_FLEXSPI_LUT_SEQ(MG_DUMMY_SDR, MG_FLEXSPI_4PAD, 0x06, MG_READ_SDR, MG_FLEXSPI_4PAD,    \
+                             0x04),                                                                \
+    [4 * 1 + 0] =                                                                                  \
+        MG_FLEXSPI_LUT_SEQ(MG_CMD_SDR, MG_FLEXSPI_1PAD, 0x05, MG_READ_SDR, MG_FLEXSPI_1PAD, 0x04), \
+    [4 * 3 + 0] =                                                                                  \
+        MG_FLEXSPI_LUT_SEQ(MG_CMD_SDR, MG_FLEXSPI_1PAD, 0x06, MG_STOP, MG_FLEXSPI_1PAD, 0x0),      \
+    [4 * 5 + 0] = MG_FLEXSPI_LUT_SEQ(MG_CMD_SDR, MG_FLEXSPI_1PAD, 0x20, MG_RADDR_SDR,              \
+                                     MG_FLEXSPI_1PAD, 0x18),                                       \
+    [4 * 8 + 0] = MG_FLEXSPI_LUT_SEQ(MG_CMD_SDR, MG_FLEXSPI_1PAD, 0xD8, MG_RADDR_SDR,              \
+                                     MG_FLEXSPI_1PAD, 0x18),                                       \
+    [4 * 9 + 0] = MG_FLEXSPI_LUT_SEQ(MG_CMD_SDR, MG_FLEXSPI_1PAD, 0x02, MG_RADDR_SDR,              \
+                                     MG_FLEXSPI_1PAD, 0x18),                                       \
+    [4 * 9 + 1] =                                                                                  \
+        MG_FLEXSPI_LUT_SEQ(MG_WRITE_SDR, MG_FLEXSPI_1PAD, 0x04, MG_STOP, MG_FLEXSPI_1PAD, 0x0),    \
+    [4 * 11 + 0] =                                                                                 \
+        MG_FLEXSPI_LUT_SEQ(MG_CMD_SDR, MG_FLEXSPI_1PAD, 0x60, MG_STOP, MG_FLEXSPI_1PAD, 0x0),      \
   }
-  memcpy(&pkt.data[n], "\x00\x00\x01\x00\x01", 5);  // A query
-  n += 5;
-  if (ipv6) pkt.data[n - 3] = 0x1c;  // AAAA query
-  // memcpy(&pkt.data[n], "\xc0\x0c\x00\x1c\x00\x01", 6);  // AAAA query
-  // n += 6;
-  return mg_send(c, &pkt, sizeof(pkt.header) + n);
+
+#define MG_FLEXSPI_LUT_OPERAND0(x) (((uint32_t) (((uint32_t) (x)))) & 0xFFU)
+#define MG_FLEXSPI_LUT_NUM_PADS0(x) (((uint32_t) (((uint32_t) (x)) << 8U)) & 0x300U)
+#define MG_FLEXSPI_LUT_OPCODE0(x) (((uint32_t) (((uint32_t) (x)) << 10U)) & 0xFC00U)
+#define MG_FLEXSPI_LUT_OPERAND1(x) (((uint32_t) (((uint32_t) (x)) << 16U)) & 0xFF0000U)
+#define MG_FLEXSPI_LUT_NUM_PADS1(x) (((uint32_t) (((uint32_t) (x)) << 24U)) & 0x3000000U)
+#define MG_FLEXSPI_LUT_OPCODE1(x) (((uint32_t) (((uint32_t) (x)) << 26U)) & 0xFC000000U)
+
+#define FLEXSPI_NOR_INSTANCE 0
+
+#if MG_DEVICE == MG_DEVICE_RT1020
+struct mg_flexspi_nor_driver_interface {
+  uint32_t version;
+  int (*init)(uint32_t instance, struct mg_flexspi_nor_config *config);
+  int (*program)(uint32_t instance, struct mg_flexspi_nor_config *config, uint32_t dst_addr,
+                 const uint32_t *src);
+  uint32_t reserved;
+  int (*erase)(uint32_t instance, struct mg_flexspi_nor_config *config, uint32_t start,
+               uint32_t lengthInBytes);
+  uint32_t reserved2;
+  int (*update_lut)(uint32_t instance, uint32_t seqIndex, const uint32_t *lutBase,
+                    uint32_t seqNumber);
+  int (*xfer)(uint32_t instance, char *xfer);
+  void (*clear_cache)(uint32_t instance);
+};
+#elif MG_DEVICE == MG_DEVICE_RT1060
+struct mg_flexspi_nor_driver_interface {
+  uint32_t version;
+  int (*init)(uint32_t instance, struct mg_flexspi_nor_config *config);
+  int (*program)(uint32_t instance, struct mg_flexspi_nor_config *config, uint32_t dst_addr,
+                 const uint32_t *src);
+  int (*erase_all)(uint32_t instance, struct mg_flexspi_nor_config *config);
+  int (*erase)(uint32_t instance, struct mg_flexspi_nor_config *config, uint32_t start,
+               uint32_t lengthInBytes);
+  int (*read)(uint32_t instance, struct mg_flexspi_nor_config *config, uint32_t *dst, uint32_t addr,
+              uint32_t lengthInBytes);
+  void (*clear_cache)(uint32_t instance);
+  int (*xfer)(uint32_t instance, char *xfer);
+  int (*update_lut)(uint32_t instance, uint32_t seqIndex, const uint32_t *lutBase,
+                    uint32_t seqNumber);
+  int (*get_config)(uint32_t instance, struct mg_flexspi_nor_config *config, uint32_t *option);
+};
+#endif
+
+#define flexspi_nor (*((struct mg_flexspi_nor_driver_interface**) \
+                          (*(uint32_t*)0x0020001c + 16)))
+
+static bool s_flash_irq_disabled;
+
+MG_IRAM void *mg_flash_start(void) {
+  return (void *) 0x60000000;
+}
+MG_IRAM size_t mg_flash_size(void) {
+  return 8 * 1024 * 1024;
+}
+MG_IRAM size_t mg_flash_sector_size(void) {
+  return 4 * 1024;  // 4k
+}
+MG_IRAM size_t mg_flash_write_align(void) {
+  return 256;
+}
+MG_IRAM int mg_flash_bank(void) {
+  return 0;
 }
 
-static void mg_sendnsreq(struct mg_connection *c, struct mg_str *name, int ms,
-                         struct mg_dns *dnsc, bool ipv6) {
-  struct dns_data *d = NULL;
-  if (dnsc->url == NULL) {
-    mg_error(c, "DNS server URL is NULL. Call mg_mgr_init()");
-  } else if (dnsc->c == NULL) {
-    dnsc->c = mg_connect(c->mgr, dnsc->url, NULL, NULL);
-    if (dnsc->c != NULL) {
-      dnsc->c->pfn = dns_cb;
-      // dnsc->c->is_hexdumping = 1;
-    }
+MG_IRAM static bool flash_page_start(volatile uint32_t *dst) {
+  char *base = (char *) mg_flash_start(), *end = base + mg_flash_size();
+  volatile char *p = (char *) dst;
+  return p >= base && p < end && ((p - base) % mg_flash_sector_size()) == 0;
+}
+
+// Note: the get_config function below works both for RT1020 and 1060
+#if MG_DEVICE == MG_DEVICE_RT1020
+MG_IRAM static int flexspi_nor_get_config(struct mg_flexspi_nor_config *config) {
+  struct mg_flexspi_nor_config default_config = {
+      .memConfig = {.tag = MG_FLEXSPI_CFG_BLK_TAG,
+                    .version = MG_FLEXSPI_CFG_BLK_VERSION,
+                    .readSampleClkSrc = 1,  // ReadSampleClk_LoopbackFromDqsPad
+                    .csHoldTime = 3,
+                    .csSetupTime = 3,
+                    .controllerMiscOption = MG_BIT(4),
+                    .deviceType = 1,  // serial NOR
+                    .sflashPadType = 4,
+                    .serialClkFreq = 7,  // 133MHz
+                    .sflashA1Size = 8 * 1024 * 1024,
+                    .lookupTable = MG_FLEXSPI_QSPI_LUT},
+      .pageSize = 256,
+      .sectorSize = 4 * 1024,
+      .ipcmdSerialClkFreq = 1,
+      .blockSize = 64 * 1024,
+      .isUniformBlockSize = false};
+
+  *config = default_config;
+  return 0;
+}
+#else
+MG_IRAM static int flexspi_nor_get_config(struct mg_flexspi_nor_config *config) {
+  uint32_t options[] = {0xc0000000, 0x00};
+
+  MG_ARM_DISABLE_IRQ();
+  uint32_t status =
+      flexspi_nor->get_config(FLEXSPI_NOR_INSTANCE, config, options);
+  if (!s_flash_irq_disabled) {
+    MG_ARM_ENABLE_IRQ();
   }
-  if (dnsc->c == NULL) {
-    mg_error(c, "resolver");
-  } else if ((d = (struct dns_data *) calloc(1, sizeof(*d))) == NULL) {
-    mg_error(c, "resolve OOM");
-  } else {
-    struct dns_data *reqs = (struct dns_data *) c->mgr->active_dns_requests;
-    d->txnid = reqs ? (uint16_t) (reqs->txnid + 1) : 1;
-    d->next = (struct dns_data *) c->mgr->active_dns_requests;
-    c->mgr->active_dns_requests = d;
-    d->expire = mg_millis() + (uint64_t) ms;
-    d->c = c;
-    c->is_resolving = 1;
-    MG_VERBOSE(("%lu resolving %.*s @ %s, txnid %hu", c->id, (int) name->len,
-                name->ptr, &dnsc->url, d->txnid));
-    if (!mg_dns_send(dnsc->c, name, d->txnid, ipv6)) {
-      mg_error(dnsc->c, "DNS send");
-    }
+  if (status) {
+    MG_ERROR(("Failed to extract flash configuration: status %u", status));
   }
+  return status;
 }
+#endif
 
-void mg_resolve(struct mg_connection *c, const char *url) {
-  struct mg_str host = mg_url_host(url);
-  c->rem.port = mg_htons(mg_url_port(url));
-  if (mg_aton(host, &c->rem)) {
-    // host is an IP address, do not fire name resolution
-    mg_connect_resolved(c);
-  } else {
-    // host is not an IP, send DNS resolution request
-    struct mg_dns *dns = c->mgr->use_dns6 ? &c->mgr->dns6 : &c->mgr->dns4;
-    mg_sendnsreq(c, &host, c->mgr->dnstimeout, dns, c->mgr->use_dns6);
+MG_IRAM bool mg_flash_erase(void *addr) {
+  struct mg_flexspi_nor_config config;
+  if (flexspi_nor_get_config(&config) != 0) {
+    return false;
+  }
+  if (flash_page_start(addr) == false) {
+    MG_ERROR(("%p is not on a sector boundary", addr));
+    return false;
+  }
+
+  void *dst = (void *)((char *) addr - (char *) mg_flash_start());
+
+  // Note: Interrupts must be disabled before any call to the ROM API on RT1020
+  // and 1060
+  MG_ARM_DISABLE_IRQ();
+  bool ok = (flexspi_nor->erase(FLEXSPI_NOR_INSTANCE, &config, (uint32_t) dst,
+                                mg_flash_sector_size()) == 0);
+  if (!s_flash_irq_disabled) {
+    MG_ARM_ENABLE_IRQ();  // Reenable them after the call
   }
+  MG_DEBUG(("Sector starting at %p erasure: %s", addr, ok ? "ok" : "fail"));
+  return ok;
 }
 
-#ifdef MG_ENABLE_LINES
-#line 1 "src/event.c"
-#endif
+MG_IRAM bool mg_flash_swap_bank(void) {
+  return true;
+}
+
+static inline void spin(volatile uint32_t count) {
+  while (count--) (void) 0;
+}
+
+static inline void flash_wait(void) {
+  while ((*((volatile uint32_t *)(0x402A8000 + 0xE0)) & MG_BIT(1)) == 0)
+    spin(1);
+}
 
+MG_IRAM static void *flash_code_location(void) {
+  return (void *) ((char *) mg_flash_start() + 0x2000);
+}
 
+MG_IRAM bool mg_flash_write(void *addr, const void *buf, size_t len) {
+  struct mg_flexspi_nor_config config;
+  if (flexspi_nor_get_config(&config) != 0) {
+    return false;
+  }
+  if ((len % mg_flash_write_align()) != 0) {
+    MG_ERROR(("%lu is not aligned to %lu", len, mg_flash_write_align()));
+    return false;
+  }
 
+  if ((char *) addr < (char *) mg_flash_start()) {
+    MG_ERROR(("Invalid flash write address: %p", addr));
+    return false;
+  }
 
+  uint32_t *dst = (uint32_t *) addr;
+  uint32_t *src = (uint32_t *) buf;
+  uint32_t *end = (uint32_t *) ((char *) buf + len);
+  bool ok = true;
+
+  // Note: If we overwrite the flash irq section of the image, we must also
+  // make sure interrupts are disabled and are not reenabled until we write
+  // this sector with another irq table.
+  if ((char *) addr == (char *) flash_code_location()) {
+    s_flash_irq_disabled = true;
+    MG_ARM_DISABLE_IRQ();
+  }
 
-void mg_call(struct mg_connection *c, int ev, void *ev_data) {
-  // Run user-defined handler first, in order to give it an ability
-  // to intercept processing (e.g. clean input buffer) before the
-  // protocol handler kicks in
-  if (c->fn != NULL) c->fn(c, ev, ev_data, c->fn_data);
-  if (c->pfn != NULL) c->pfn(c, ev, ev_data, c->pfn_data);
+  while (ok && src < end) {
+    if (flash_page_start(dst) && mg_flash_erase(dst) == false) {
+      break;
+    }
+    uint32_t status;
+    uint32_t dst_ofs = (uint32_t) dst - (uint32_t) mg_flash_start();
+    if ((char *) buf >= (char *) mg_flash_start()) {
+      // If we copy from FLASH to FLASH, then we first need to copy the source
+      // to RAM
+      size_t tmp_buf_size = mg_flash_write_align() / sizeof(uint32_t);
+      uint32_t tmp[tmp_buf_size];
+
+      for (size_t i = 0; i < tmp_buf_size; i++) {
+        flash_wait();
+        tmp[i] = src[i];
+      }
+      MG_ARM_DISABLE_IRQ();
+      status = flexspi_nor->program(FLEXSPI_NOR_INSTANCE, &config,
+                                    (uint32_t) dst_ofs, tmp);
+    } else {
+      MG_ARM_DISABLE_IRQ();
+      status = flexspi_nor->program(FLEXSPI_NOR_INSTANCE, &config,
+                                    (uint32_t) dst_ofs, src);
+    }
+    if (!s_flash_irq_disabled) {
+      MG_ARM_ENABLE_IRQ();
+    }
+    src = (uint32_t *) ((char *) src + mg_flash_write_align());
+    dst = (uint32_t *) ((char *) dst + mg_flash_write_align());
+    if (status != 0) {
+      ok = false;
+    }
+  }
+  MG_DEBUG(("Flash write %lu bytes @ %p: %s.", len, dst, ok ? "ok" : "fail"));
+  return ok;
 }
 
-void mg_error(struct mg_connection *c, const char *fmt, ...) {
-  char buf[64];
-  va_list ap;
-  va_start(ap, fmt);
-  mg_vsnprintf(buf, sizeof(buf), fmt, &ap);
-  va_end(ap);
-  MG_ERROR(("%lu %p %s", c->id, c->fd, buf));
-  c->is_closing = 1;             // Set is_closing before sending MG_EV_CALL
-  mg_call(c, MG_EV_ERROR, buf);  // Let user handler to override it
+MG_IRAM void mg_device_reset(void) {
+  MG_DEBUG(("Resetting device..."));
+  *(volatile unsigned long *) 0xe000ed0c = 0x5fa0004;
 }
 
+#endif
+
 #ifdef MG_ENABLE_LINES
-#line 1 "src/fmt.c"
+#line 1 "src/device_stm32h5.c"
 #endif
 
 
 
+#if MG_DEVICE == MG_DEVICE_STM32H5
 
-static void mg_pfn_iobuf_private(char ch, void *param, bool expand) {
-  struct mg_iobuf *io = (struct mg_iobuf *) param;
-  if (expand && io->len + 2 > io->size) mg_iobuf_resize(io, io->len + 2);
-  if (io->len + 2 <= io->size) {
-    io->buf[io->len++] = (uint8_t) ch;
-    io->buf[io->len] = 0;
-  } else if (io->len < io->size) {
-    io->buf[io->len++] = 0;  // Guarantee to 0-terminate
-  }
-}
+#define FLASH_BASE 0x40022000          // Base address of the flash controller
+#define FLASH_KEYR (FLASH_BASE + 0x4)  // See RM0481 7.11
+#define FLASH_OPTKEYR (FLASH_BASE + 0xc)
+#define FLASH_OPTCR (FLASH_BASE + 0x1c)
+#define FLASH_NSSR (FLASH_BASE + 0x20)
+#define FLASH_NSCR (FLASH_BASE + 0x28)
+#define FLASH_NSCCR (FLASH_BASE + 0x30)
+#define FLASH_OPTSR_CUR (FLASH_BASE + 0x50)
+#define FLASH_OPTSR_PRG (FLASH_BASE + 0x54)
 
-static void mg_putchar_iobuf_static(char ch, void *param) {
-  mg_pfn_iobuf_private(ch, param, false);
+void *mg_flash_start(void) {
+  return (void *) 0x08000000;
 }
-
-void mg_pfn_iobuf(char ch, void *param) {
-  mg_pfn_iobuf_private(ch, param, true);
+size_t mg_flash_size(void) {
+  return 2 * 1024 * 1024;  // 2Mb
 }
-
-size_t mg_vsnprintf(char *buf, size_t len, const char *fmt, va_list *ap) {
-  struct mg_iobuf io = {(uint8_t *) buf, len, 0, 0};
-  size_t n = mg_vxprintf(mg_putchar_iobuf_static, &io, fmt, ap);
-  if (n < len) buf[n] = '\0';
-  return n;
+size_t mg_flash_sector_size(void) {
+  return 8 * 1024;  // 8k
 }
-
-size_t mg_snprintf(char *buf, size_t len, const char *fmt, ...) {
-  va_list ap;
-  size_t n;
-  va_start(ap, fmt);
-  n = mg_vsnprintf(buf, len, fmt, &ap);
-  va_end(ap);
-  return n;
+size_t mg_flash_write_align(void) {
+  return 16;  // 128 bit
 }
-
-char *mg_vmprintf(const char *fmt, va_list *ap) {
-  struct mg_iobuf io = {0, 0, 0, 256};
-  mg_vxprintf(mg_pfn_iobuf, &io, fmt, ap);
-  return (char *) io.buf;
+int mg_flash_bank(void) {
+  return MG_REG(FLASH_OPTCR) & MG_BIT(31) ? 2 : 1;
 }
 
-char *mg_mprintf(const char *fmt, ...) {
-  char *s;
-  va_list ap;
-  va_start(ap, fmt);
-  s = mg_vmprintf(fmt, &ap);
-  va_end(ap);
-  return s;
+static void flash_unlock(void) {
+  static bool unlocked = false;
+  if (unlocked == false) {
+    MG_REG(FLASH_KEYR) = 0x45670123;
+    MG_REG(FLASH_KEYR) = 0Xcdef89ab;
+    MG_REG(FLASH_OPTKEYR) = 0x08192a3b;
+    MG_REG(FLASH_OPTKEYR) = 0x4c5d6e7f;
+    unlocked = true;
+  }
 }
 
-size_t mg_xprintf(void (*out)(char, void *), void *ptr, const char *fmt, ...) {
-  size_t len = 0;
-  va_list ap;
-  va_start(ap, fmt);
-  len = mg_vxprintf(out, ptr, fmt, &ap);
-  va_end(ap);
-  return len;
+static int flash_page_start(volatile uint32_t *dst) {
+  char *base = (char *) mg_flash_start(), *end = base + mg_flash_size();
+  volatile char *p = (char *) dst;
+  return p >= base && p < end && ((p - base) % mg_flash_sector_size()) == 0;
 }
 
-static bool is_digit(int c) {
-  return c >= '0' && c <= '9';
+static bool flash_is_err(void) {
+  return MG_REG(FLASH_NSSR) & ((MG_BIT(8) - 1) << 17);  // RM0481 7.11.9
 }
 
-static int addexp(char *buf, int e, int sign) {
-  int n = 0;
-  buf[n++] = 'e';
-  buf[n++] = (char) sign;
-  if (e > 400) return 0;
-  if (e < 10) buf[n++] = '0';
-  if (e >= 100) buf[n++] = (char) (e / 100 + '0'), e -= 100 * (e / 100);
-  if (e >= 10) buf[n++] = (char) (e / 10 + '0'), e -= 10 * (e / 10);
-  buf[n++] = (char) (e + '0');
-  return n;
+static void flash_wait(void) {
+  while ((MG_REG(FLASH_NSSR) & MG_BIT(0)) &&
+         (MG_REG(FLASH_NSSR) & MG_BIT(16)) == 0) {
+    (void) 0;
+  }
 }
 
-static int xisinf(double x) {
-  union {
-    double f;
-    uint64_t u;
-  } ieee754 = {x};
-  return ((unsigned) (ieee754.u >> 32) & 0x7fffffff) == 0x7ff00000 &&
-         ((unsigned) ieee754.u == 0);
+static void flash_clear_err(void) {
+  flash_wait();                                    // Wait until ready
+  MG_REG(FLASH_NSCCR) = ((MG_BIT(9) - 1) << 16U);  // Clear all errors
 }
 
-static int xisnan(double x) {
-  union {
-    double f;
-    uint64_t u;
-  } ieee754 = {x};
-  return ((unsigned) (ieee754.u >> 32) & 0x7fffffff) +
-             ((unsigned) ieee754.u != 0) >
-         0x7ff00000;
+static bool flash_bank_is_swapped(void) {
+  return MG_REG(FLASH_OPTCR) & MG_BIT(31);  // RM0481 7.11.8
 }
 
-static size_t mg_dtoa(char *dst, size_t dstlen, double d, int width) {
-  char buf[40];
-  int i, s = 0, n = 0, e = 0;
-  double t, mul, saved;
-  if (d == 0.0) return mg_snprintf(dst, dstlen, "%s", "0");
-  if (xisinf(d)) return mg_snprintf(dst, dstlen, "%s", d > 0 ? "inf" : "-inf");
-  if (xisnan(d)) return mg_snprintf(dst, dstlen, "%s", "nan");
-  if (d < 0.0) d = -d, buf[s++] = '-';
-
-  // Round
-  saved = d;
-  mul = 1.0;
-  while (d >= 10.0 && d / mul >= 10.0) mul *= 10.0;
-  while (d <= 1.0 && d / mul <= 1.0) mul /= 10.0;
-  for (i = 0, t = mul * 5; i < width; i++) t /= 10.0;
-  d += t;
-  // Calculate exponent, and 'mul' for scientific representation
-  mul = 1.0;
-  while (d >= 10.0 && d / mul >= 10.0) mul *= 10.0, e++;
-  while (d < 1.0 && d / mul < 1.0) mul /= 10.0, e--;
-  // printf(" --> %g %d %g %g\n", saved, e, t, mul);
-
-  if (e >= width) {
-    n = (int) mg_dtoa(buf, sizeof(buf), saved / mul, width);
-    // printf(" --> %.*g %d [%.*s]\n", 10, d / t, e, n, buf);
-    n += addexp(buf + s + n, e, '+');
-    return mg_snprintf(dst, dstlen, "%.*s", n, buf);
-  } else if (e <= -width) {
-    n = (int) mg_dtoa(buf, sizeof(buf), saved / mul, width);
-    // printf(" --> %.*g %d [%.*s]\n", 10, d / mul, e, n, buf);
-    n += addexp(buf + s + n, -e, '-');
-    return mg_snprintf(dst, dstlen, "%.*s", n, buf);
+bool mg_flash_erase(void *location) {
+  bool ok = false;
+  if (flash_page_start(location) == false) {
+    MG_ERROR(("%p is not on a sector boundary"));
   } else {
-    for (i = 0, t = mul; t >= 1.0 && s + n < (int) sizeof(buf); i++) {
-      int ch = (int) (d / t);
-      if (n > 0 || ch > 0) buf[s + n++] = (char) (ch + '0');
-      d -= ch * t;
-      t /= 10.0;
-    }
-    // printf(" --> [%g] -> %g %g (%d) [%.*s]\n", saved, d, t, n, s + n, buf);
-    if (n == 0) buf[s++] = '0';
-    while (t >= 1.0 && n + s < (int) sizeof(buf)) buf[n++] = '0', t /= 10.0;
-    if (s + n < (int) sizeof(buf)) buf[n + s++] = '.';
-    // printf(" 1--> [%g] -> [%.*s]\n", saved, s + n, buf);
-    for (i = 0, t = 0.1; s + n < (int) sizeof(buf) && n < width; i++) {
-      int ch = (int) (d / t);
-      buf[s + n++] = (char) (ch + '0');
-      d -= ch * t;
-      t /= 10.0;
+    uintptr_t diff = (char *) location - (char *) mg_flash_start();
+    uint32_t sector = diff / mg_flash_sector_size();
+    uint32_t saved_cr = MG_REG(FLASH_NSCR); // Save CR value
+    flash_unlock();
+    flash_clear_err();
+    MG_REG(FLASH_NSCR) = 0;
+    if ((sector < 128 && flash_bank_is_swapped()) ||
+        (sector > 127 && !flash_bank_is_swapped())) {
+      MG_REG(FLASH_NSCR) |= MG_BIT(31);  // Set FLASH_CR_BKSEL
     }
+    if (sector > 127) sector -= 128;
+    MG_REG(FLASH_NSCR) |= MG_BIT(2) | (sector << 6);  // Erase | sector_num
+    MG_REG(FLASH_NSCR) |= MG_BIT(5);                  // Start erasing
+    flash_wait();
+    ok = !flash_is_err();
+    MG_DEBUG(("Erase sector %lu @ %p: %s. CR %#lx SR %#lx", sector, location,
+              ok ? "ok" : "fail", MG_REG(FLASH_NSCR), MG_REG(FLASH_NSSR)));
+    // mg_hexdump(location, 32);
+    MG_REG(FLASH_NSCR) = saved_cr; // Restore saved CR
   }
-  while (n > 0 && buf[s + n - 1] == '0') n--;  // Trim trailing zeros
-  if (n > 0 && buf[s + n - 1] == '.') n--;     // Trim trailing dot
-  n += s;
-  if (n >= (int) sizeof(buf)) n = (int) sizeof(buf) - 1;
-  buf[n] = '\0';
-  return mg_snprintf(dst, dstlen, "%s", buf);
+  return ok;
 }
 
-static size_t mg_lld(char *buf, int64_t val, bool is_signed, bool is_hex) {
-  const char *letters = "0123456789abcdef";
-  uint64_t v = (uint64_t) val;
-  size_t s = 0, n, i;
-  if (is_signed && val < 0) buf[s++] = '-', v = (uint64_t) (-val);
-  // This loop prints a number in reverse order. I guess this is because we
-  // write numbers from right to left: least significant digit comes last.
-  // Maybe because we use Arabic numbers, and Arabs write RTL?
-  if (is_hex) {
-    for (n = 0; v; v >>= 4) buf[s + n++] = letters[v & 15];
-  } else {
-    for (n = 0; v; v /= 10) buf[s + n++] = letters[v % 10];
+bool mg_flash_swap_bank(void) {
+  uint32_t desired = flash_bank_is_swapped() ? 0 : MG_BIT(31);
+  flash_unlock();
+  flash_clear_err();
+  // printf("OPTSR_PRG 1 %#lx\n", FLASH->OPTSR_PRG);
+  MG_SET_BITS(MG_REG(FLASH_OPTSR_PRG), MG_BIT(31), desired);
+  // printf("OPTSR_PRG 2 %#lx\n", FLASH->OPTSR_PRG);
+  MG_REG(FLASH_OPTCR) |= MG_BIT(1);  // OPTSTART
+  while ((MG_REG(FLASH_OPTSR_CUR) & MG_BIT(31)) != desired) (void) 0;
+  return true;
+}
+
+bool mg_flash_write(void *addr, const void *buf, size_t len) {
+  if ((len % mg_flash_write_align()) != 0) {
+    MG_ERROR(("%lu is not aligned to %lu", len, mg_flash_write_align()));
+    return false;
   }
-  // Reverse a string
-  for (i = 0; i < n / 2; i++) {
-    char t = buf[s + i];
-    buf[s + i] = buf[s + n - i - 1], buf[s + n - i - 1] = t;
+  uint32_t *dst = (uint32_t *) addr;
+  uint32_t *src = (uint32_t *) buf;
+  uint32_t *end = (uint32_t *) ((char *) buf + len);
+  bool ok = true;
+  flash_unlock();
+  flash_clear_err();
+  MG_ARM_DISABLE_IRQ();
+  // MG_DEBUG(("Starting flash write %lu bytes @ %p", len, addr));
+  MG_REG(FLASH_NSCR) = MG_BIT(1);  // Set programming flag
+  while (ok && src < end) {
+    if (flash_page_start(dst) && mg_flash_erase(dst) == false) break;
+    *(volatile uint32_t *) dst++ = *src++;
+    flash_wait();
+    if (flash_is_err()) ok = false;
   }
-  if (val == 0) buf[n++] = '0';  // Handle special case
-  return n + s;
+  MG_ARM_ENABLE_IRQ();
+  MG_DEBUG(("Flash write %lu bytes @ %p: %s. CR %#lx SR %#lx", len, dst,
+            flash_is_err() ? "fail" : "ok", MG_REG(FLASH_NSCR),
+            MG_REG(FLASH_NSSR)));
+  MG_REG(FLASH_NSCR) = 0;  // Clear flags
+  return ok;
 }
 
-static size_t scpy(void (*out)(char, void *), void *ptr, char *buf,
-                   size_t len) {
-  size_t i = 0;
-  while (i < len && buf[i] != '\0') out(buf[i++], ptr);
-  return i;
+void mg_device_reset(void) {
+  // SCB->AIRCR = ((0x5fa << SCB_AIRCR_VECTKEY_Pos)|SCB_AIRCR_SYSRESETREQ_Msk);
+  *(volatile unsigned long *) 0xe000ed0c = 0x5fa0004;
 }
+#endif
 
-static char mg_esc(int c, bool esc) {
-  const char *p, *esc1 = "\b\f\n\r\t\\\"", *esc2 = "bfnrt\\\"";
-  for (p = esc ? esc1 : esc2; *p != '\0'; p++) {
-    if (*p == c) return esc ? esc2[p - esc1] : esc1[p - esc2];
+#ifdef MG_ENABLE_LINES
+#line 1 "src/device_stm32h7.c"
+#endif
+
+
+
+#if MG_DEVICE == MG_DEVICE_STM32H7
+
+#define FLASH_BASE1 0x52002000  // Base address for bank1
+#define FLASH_BASE2 0x52002100  // Base address for bank2
+#define FLASH_KEYR 0x04         // See RM0433 4.9.2
+#define FLASH_OPTKEYR 0x08
+#define FLASH_OPTCR 0x18
+#define FLASH_SR 0x10
+#define FLASH_CR 0x0c
+#define FLASH_CCR 0x14
+#define FLASH_OPTSR_CUR 0x1c
+#define FLASH_OPTSR_PRG 0x20
+#define FLASH_SIZE_REG 0x1ff1e880
+
+MG_IRAM void *mg_flash_start(void) {
+  return (void *) 0x08000000;
+}
+MG_IRAM size_t mg_flash_size(void) {
+  return MG_REG(FLASH_SIZE_REG) * 1024;
+}
+MG_IRAM size_t mg_flash_sector_size(void) {
+  return 128 * 1024;  // 128k
+}
+MG_IRAM size_t mg_flash_write_align(void) {
+  return 32;  // 256 bit
+}
+MG_IRAM int mg_flash_bank(void) {
+  if (mg_flash_size() < 2 * 1024 * 1024) return 0;  // No dual bank support
+  return MG_REG(FLASH_BASE1 + FLASH_OPTCR) & MG_BIT(31) ? 2 : 1;
+}
+
+MG_IRAM static void flash_unlock(void) {
+  static bool unlocked = false;
+  if (unlocked == false) {
+    MG_REG(FLASH_BASE1 + FLASH_KEYR) = 0x45670123;
+    MG_REG(FLASH_BASE1 + FLASH_KEYR) = 0xcdef89ab;
+    if (mg_flash_bank() > 0) {
+      MG_REG(FLASH_BASE2 + FLASH_KEYR) = 0x45670123;
+      MG_REG(FLASH_BASE2 + FLASH_KEYR) = 0xcdef89ab;
+    }
+    MG_REG(FLASH_BASE1 + FLASH_OPTKEYR) = 0x08192a3b;  // opt reg is "shared"
+    MG_REG(FLASH_BASE1 + FLASH_OPTKEYR) = 0x4c5d6e7f;  // thus unlock once
+    unlocked = true;
   }
-  return 0;
 }
 
-static char mg_escape(int c) {
-  return mg_esc(c, true);
+MG_IRAM static bool flash_page_start(volatile uint32_t *dst) {
+  char *base = (char *) mg_flash_start(), *end = base + mg_flash_size();
+  volatile char *p = (char *) dst;
+  return p >= base && p < end && ((p - base) % mg_flash_sector_size()) == 0;
 }
 
-static size_t qcpy(void (*out)(char, void *), void *ptr, char *buf,
-                   size_t len) {
-  size_t i = 0, extra = 0;
-  for (i = 0; i < len && buf[i] != '\0'; i++) {
-    char c = mg_escape(buf[i]);
-    if (c) {
-      out('\\', ptr), out(c, ptr), extra++;
-    } else {
-      out(buf[i], ptr);
-    }
-  }
-  return i + extra;
+MG_IRAM static bool flash_is_err(uint32_t bank) {
+  return MG_REG(bank + FLASH_SR) & ((MG_BIT(11) - 1) << 17);  // RM0433 4.9.5
 }
 
-static size_t Qcpy(void (*out)(char, void *), void *ptr, char *buf,
-                   size_t len) {
-  size_t n = 2;
-  out('"', ptr);
-  n += qcpy(out, ptr, buf, len);
-  out('"', ptr);
-  return n;
+MG_IRAM static void flash_wait(uint32_t bank) {
+  while (MG_REG(bank + FLASH_SR) & (MG_BIT(0) | MG_BIT(2))) (void) 0;
 }
 
-static size_t bcpy(void (*out)(char, void *), void *ptr, uint8_t *buf,
-                   size_t len) {
-  size_t i, n = 0;
-  const char *t =
-      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
-  out('"', ptr), n++;
-  for (i = 0; i < len; i += 3) {
-    uint8_t c1 = buf[i], c2 = i + 1 < len ? buf[i + 1] : 0,
-            c3 = i + 2 < len ? buf[i + 2] : 0;
-    char tmp[4] = {t[c1 >> 2], t[(c1 & 3) << 4 | (c2 >> 4)], '=', '='};
-    if (i + 1 < len) tmp[2] = t[(c2 & 15) << 2 | (c3 >> 6)];
-    if (i + 2 < len) tmp[3] = t[c3 & 63];
-    n += scpy(out, ptr, tmp, sizeof(tmp));
-  }
-  out('"', ptr), n++;
-  return n;
+MG_IRAM static void flash_clear_err(uint32_t bank) {
+  flash_wait(bank);                                      // Wait until ready
+  MG_REG(bank + FLASH_CCR) = ((MG_BIT(11) - 1) << 16U);  // Clear all errors
 }
 
-size_t mg_vxprintf(void (*out)(char, void *), void *param, const char *fmt,
-                   va_list *ap) {
-  size_t i = 0, n = 0;
-  while (fmt[i] != '\0') {
-    if (fmt[i] == '%') {
-      size_t j, k, x = 0, is_long = 0, w = 0 /* width */, pr = ~0U /* prec */;
-      char pad = ' ', minus = 0, c = fmt[++i];
-      if (c == '#') x++, c = fmt[++i];
-      if (c == '-') minus++, c = fmt[++i];
-      if (c == '0') pad = '0', c = fmt[++i];
-      while (is_digit(c)) w *= 10, w += (size_t) (c - '0'), c = fmt[++i];
-      if (c == '.') {
-        c = fmt[++i];
-        if (c == '*') {
-          pr = (size_t) va_arg(*ap, int);
-          c = fmt[++i];
-        } else {
-          pr = 0;
-          while (is_digit(c)) pr *= 10, pr += (size_t) (c - '0'), c = fmt[++i];
-        }
-      }
-      while (c == 'h') c = fmt[++i];  // Treat h and hh as int
-      if (c == 'l') {
-        is_long++, c = fmt[++i];
-        if (c == 'l') is_long++, c = fmt[++i];
-      }
-      if (c == 'p') x = 1, is_long = 1;
-      if (c == 'd' || c == 'u' || c == 'x' || c == 'X' || c == 'p' ||
-          c == 'g' || c == 'f') {
-        bool s = (c == 'd'), h = (c == 'x' || c == 'X' || c == 'p');
-        char tmp[40];
-        size_t xl = x ? 2 : 0;
-        if (c == 'g' || c == 'f') {
-          double v = va_arg(*ap, double);
-          if (pr == ~0U) pr = 6;
-          k = mg_dtoa(tmp, sizeof(tmp), v, (int) pr);
-        } else if (is_long == 2) {
-          int64_t v = va_arg(*ap, int64_t);
-          k = mg_lld(tmp, v, s, h);
-        } else if (is_long == 1) {
-          long v = va_arg(*ap, long);
-          k = mg_lld(tmp, s ? (int64_t) v : (int64_t) (unsigned long) v, s, h);
-        } else {
-          int v = va_arg(*ap, int);
-          k = mg_lld(tmp, s ? (int64_t) v : (int64_t) (unsigned) v, s, h);
-        }
-        for (j = 0; j < xl && w > 0; j++) w--;
-        for (j = 0; pad == ' ' && !minus && k < w && j + k < w; j++)
-          n += scpy(out, param, &pad, 1);
-        n += scpy(out, param, (char *) "0x", xl);
-        for (j = 0; pad == '0' && k < w && j + k < w; j++)
-          n += scpy(out, param, &pad, 1);
-        n += scpy(out, param, tmp, k);
-        for (j = 0; pad == ' ' && minus && k < w && j + k < w; j++)
-          n += scpy(out, param, &pad, 1);
-      } else if (c == 'M') {
-        mg_pm_t f = va_arg(*ap, mg_pm_t);
-        n += f(out, param, ap);
-      } else if (c == 'c') {
-        int ch = va_arg(*ap, int);
-        out((char) ch, param);
-        n++;
-      } else if (c == 'H') {
-        // Print hex-encoded double-quoted string
-        size_t bl = (size_t) va_arg(*ap, int);
-        uint8_t *p = va_arg(*ap, uint8_t *), dquote = '"';
-        const char *hex = "0123456789abcdef";
-        n += scpy(out, param, (char *) &dquote, 1);
-        for (j = 0; j < bl; j++) {
-          n += scpy(out, param, (char *) &hex[(p[j] >> 4) & 15], 1);
-          n += scpy(out, param, (char *) &hex[p[j] & 15], 1);
-        }
-        n += scpy(out, param, (char *) &dquote, 1);
-      } else if (c == 'I') {
-        // Print IPv4 or IPv6 address
-        size_t len = (size_t) va_arg(*ap, int);  // Length 16 means IPv6 address
-        uint8_t *buf = va_arg(*ap, uint8_t *);   // Pointer to the IP address
-        if (len == 6) {
-          uint16_t *p = (uint16_t *) buf;
-          n += mg_xprintf(out, param, "%x:%x:%x:%x:%x:%x:%x:%x", mg_htons(p[0]),
-                          mg_htons(p[1]), mg_htons(p[2]), mg_htons(p[3]),
-                          mg_htons(p[4]), mg_htons(p[5]), mg_htons(p[6]),
-                          mg_htons(p[7]));
-        } else {
-          n += mg_xprintf(out, param, "%d.%d.%d.%d", (int) buf[0], (int) buf[1],
-                          (int) buf[2], (int) buf[3]);
-        }
-      } else if (c == 'A') {
-        // Print hardware addresses (currently Ethernet MAC)
-        uint8_t *buf = va_arg(*ap, uint8_t *);  // Pointer to the hw address
-        n += mg_xprintf(out, param, "%02x:%02x:%02x:%02x:%02x:%02x",
-                        (int) buf[0], (int) buf[1], (int) buf[2], (int) buf[3],
-                        (int) buf[4], (int) buf[5]);
-      } else if (c == 'V') {
-        // Print base64-encoded double-quoted string
-        size_t len = (size_t) va_arg(*ap, int);
-        uint8_t *buf = va_arg(*ap, uint8_t *);
-        n += bcpy(out, param, buf, len);
-      } else if (c == 's' || c == 'Q' || c == 'q') {
-        char *p = va_arg(*ap, char *);
-        size_t (*f)(void (*)(char, void *), void *, char *, size_t) = scpy;
-        if (c == 'Q') f = Qcpy;
-        if (c == 'q') f = qcpy;
-        if (pr == ~0U) pr = p == NULL ? 0 : strlen(p);
-        for (j = 0; !minus && pr < w && j + pr < w; j++)
-          n += f(out, param, &pad, 1);
-        n += f(out, param, p, pr);
-        for (j = 0; minus && pr < w && j + pr < w; j++)
-          n += f(out, param, &pad, 1);
-      } else if (c == '%') {
-        out('%', param);
-        n++;
-      } else {
-        out('%', param);
-        out(c, param);
-        n += 2;
-      }
-      i++;
-    } else {
-      out(fmt[i], param), n++, i++;
-    }
-  }
-  return n;
+MG_IRAM static bool flash_bank_is_swapped(uint32_t bank) {
+  return MG_REG(bank + FLASH_OPTCR) & MG_BIT(31);  // RM0433 4.9.7
 }
 
-#ifdef MG_ENABLE_LINES
-#line 1 "src/fs.c"
-#endif
-
-
-
-struct mg_fd *mg_fs_open(struct mg_fs *fs, const char *path, int flags) {
-  struct mg_fd *fd = (struct mg_fd *) calloc(1, sizeof(*fd));
-  if (fd != NULL) {
-    fd->fd = fs->op(path, flags);
-    fd->fs = fs;
-    if (fd->fd == NULL) {
-      free(fd);
-      fd = NULL;
-    }
-  }
-  return fd;
+// Figure out flash bank based on the address
+MG_IRAM static uint32_t flash_bank(void *addr) {
+  size_t ofs = (char *) addr - (char *) mg_flash_start();
+  if (mg_flash_bank() == 0) return FLASH_BASE1;
+  return ofs < mg_flash_size() / 2 ? FLASH_BASE1 : FLASH_BASE2;
 }
 
-void mg_fs_close(struct mg_fd *fd) {
-  if (fd != NULL) {
-    fd->fs->cl(fd->fd);
-    free(fd);
+MG_IRAM bool mg_flash_erase(void *addr) {
+  bool ok = false;
+  if (flash_page_start(addr) == false) {
+    MG_ERROR(("%p is not on a sector boundary", addr));
+  } else {
+    uintptr_t diff = (char *) addr - (char *) mg_flash_start();
+    uint32_t sector = diff / mg_flash_sector_size();
+    uint32_t bank = flash_bank(addr);
+    uint32_t saved_cr = MG_REG(bank + FLASH_CR);  // Save CR value
+
+    flash_unlock();
+    if (sector > 7) sector -= 8;
+
+    flash_clear_err(bank);
+    MG_REG(bank + FLASH_CR) = MG_BIT(5);             // 32-bit write parallelism
+    MG_REG(bank + FLASH_CR) |= (sector & 7U) << 8U;  // Sector to erase
+    MG_REG(bank + FLASH_CR) |= MG_BIT(2);            // Sector erase bit
+    MG_REG(bank + FLASH_CR) |= MG_BIT(7);            // Start erasing
+    ok = !flash_is_err(bank);
+    MG_DEBUG(("Erase sector %lu @ %p %s. CR %#lx SR %#lx", sector, addr,
+              ok ? "ok" : "fail", MG_REG(bank + FLASH_CR),
+              MG_REG(bank + FLASH_SR)));
+    MG_REG(bank + FLASH_CR) = saved_cr;  // Restore CR
   }
+  return ok;
 }
 
-char *mg_file_read(struct mg_fs *fs, const char *path, size_t *sizep) {
-  struct mg_fd *fd;
-  char *data = NULL;
-  size_t size = 0;
-  fs->st(path, &size, NULL);
-  if ((fd = mg_fs_open(fs, path, MG_FS_READ)) != NULL) {
-    data = (char *) calloc(1, size + 1);
-    if (data != NULL) {
-      if (fs->rd(fd->fd, data, size) != size) {
-        free(data);
-        data = NULL;
-      } else {
-        data[size] = '\0';
-        if (sizep != NULL) *sizep = size;
-      }
-    }
-    mg_fs_close(fd);
-  }
-  return data;
+MG_IRAM bool mg_flash_swap_bank(void) {
+  if (mg_flash_bank() == 0) return true;
+  uint32_t bank = FLASH_BASE1;
+  uint32_t desired = flash_bank_is_swapped(bank) ? 0 : MG_BIT(31);
+  flash_unlock();
+  flash_clear_err(bank);
+  // printf("OPTSR_PRG 1 %#lx\n", FLASH->OPTSR_PRG);
+  MG_SET_BITS(MG_REG(bank + FLASH_OPTSR_PRG), MG_BIT(31), desired);
+  // printf("OPTSR_PRG 2 %#lx\n", FLASH->OPTSR_PRG);
+  MG_REG(bank + FLASH_OPTCR) |= MG_BIT(1);  // OPTSTART
+  while ((MG_REG(bank + FLASH_OPTSR_CUR) & MG_BIT(31)) != desired) (void) 0;
+  return true;
 }
 
-bool mg_file_write(struct mg_fs *fs, const char *path, const void *buf,
-                   size_t len) {
-  bool result = false;
-  struct mg_fd *fd;
-  char tmp[MG_PATH_MAX];
-  mg_snprintf(tmp, sizeof(tmp), "%s..%d", path, rand());
-  if ((fd = mg_fs_open(fs, tmp, MG_FS_WRITE)) != NULL) {
-    result = fs->wr(fd->fd, buf, len) == len;
-    mg_fs_close(fd);
-    if (result) {
-      fs->rm(path);
-      fs->mv(tmp, path);
-    } else {
-      fs->rm(tmp);
-    }
+MG_IRAM bool mg_flash_write(void *addr, const void *buf, size_t len) {
+  if ((len % mg_flash_write_align()) != 0) {
+    MG_ERROR(("%lu is not aligned to %lu", len, mg_flash_write_align()));
+    return false;
   }
-  return result;
+  uint32_t bank = flash_bank(addr);
+  uint32_t *dst = (uint32_t *) addr;
+  uint32_t *src = (uint32_t *) buf;
+  uint32_t *end = (uint32_t *) ((char *) buf + len);
+  bool ok = true;
+  flash_unlock();
+  flash_clear_err(bank);
+  MG_REG(bank + FLASH_CR) = MG_BIT(1);   // Set programming flag
+  MG_REG(bank + FLASH_CR) |= MG_BIT(5);  // 32-bit write parallelism
+  MG_DEBUG(("Writing flash @ %p, %lu bytes", addr, len));
+  MG_ARM_DISABLE_IRQ();
+  while (ok && src < end) {
+    if (flash_page_start(dst) && mg_flash_erase(dst) == false) break;
+    *(volatile uint32_t *) dst++ = *src++;
+    flash_wait(bank);
+    if (flash_is_err(bank)) ok = false;
+  }
+  MG_ARM_ENABLE_IRQ();
+  MG_DEBUG(("Flash write %lu bytes @ %p: %s. CR %#lx SR %#lx", len, dst,
+            ok ? "ok" : "fail", MG_REG(bank + FLASH_CR),
+            MG_REG(bank + FLASH_SR)));
+  MG_REG(bank + FLASH_CR) &= ~MG_BIT(1);  // Clear programming flag
+  return ok;
 }
 
-bool mg_file_printf(struct mg_fs *fs, const char *path, const char *fmt, ...) {
-  va_list ap;
-  char *data;
-  bool result = false;
-  va_start(ap, fmt);
-  data = mg_vmprintf(fmt, &ap);
-  va_end(ap);
-  result = mg_file_write(fs, path, data, strlen(data));
-  free(data);
-  return result;
+MG_IRAM void mg_device_reset(void) {
+  // SCB->AIRCR = ((0x5fa << SCB_AIRCR_VECTKEY_Pos)|SCB_AIRCR_SYSRESETREQ_Msk);
+  *(volatile unsigned long *) 0xe000ed0c = 0x5fa0004;
 }
+#endif
 
 #ifdef MG_ENABLE_LINES
-#line 1 "src/fs_fat.c"
+#line 1 "src/dns.c"
 #endif
 
 
 
-#if MG_ENABLE_FATFS
-#include <ff.h>
 
-static int mg_days_from_epoch(int y, int m, int d) {
-  y -= m <= 2;
-  int era = y / 400;
-  int yoe = y - era * 400;
-  int doy = (153 * (m + (m > 2 ? -3 : 9)) + 2) / 5 + d - 1;
-  int doe = yoe * 365 + yoe / 4 - yoe / 100 + doy;
-  return era * 146097 + doe - 719468;
-}
 
-static time_t mg_timegm(const struct tm *t) {
-  int year = t->tm_year + 1900;
-  int month = t->tm_mon;  // 0-11
-  if (month > 11) {
-    year += month / 12;
-    month %= 12;
-  } else if (month < 0) {
-    int years_diff = (11 - month) / 12;
-    year -= years_diff;
-    month += 12 * years_diff;
-  }
-  int x = mg_days_from_epoch(year, month + 1, t->tm_mday);
-  return 60 * (60 * (24L * x + t->tm_hour) + t->tm_min) + t->tm_sec;
-}
 
-static time_t ff_time_to_epoch(uint16_t fdate, uint16_t ftime) {
-  struct tm tm;
-  memset(&tm, 0, sizeof(struct tm));
-  tm.tm_sec = (ftime << 1) & 0x3e;
-  tm.tm_min = ((ftime >> 5) & 0x3f);
-  tm.tm_hour = ((ftime >> 11) & 0x1f);
-  tm.tm_mday = (fdate & 0x1f);
-  tm.tm_mon = ((fdate >> 5) & 0x0f) - 1;
-  tm.tm_year = ((fdate >> 9) & 0x7f) + 80;
-  return mg_timegm(&tm);
-}
 
-static int ff_stat(const char *path, size_t *size, time_t *mtime) {
-  FILINFO fi;
-  if (path[0] == '\0') {
-    if (size) *size = 0;
-    if (mtime) *mtime = 0;
-    return MG_FS_DIR;
-  } else if (f_stat(path, &fi) == 0) {
-    if (size) *size = (size_t) fi.fsize;
-    if (mtime) *mtime = ff_time_to_epoch(fi.fdate, fi.ftime);
-    return MG_FS_READ | MG_FS_WRITE | ((fi.fattrib & AM_DIR) ? MG_FS_DIR : 0);
-  } else {
-    return 0;
-  }
-}
 
-static void ff_list(const char *dir, void (*fn)(const char *, void *),
-                    void *userdata) {
-  DIR d;
-  FILINFO fi;
-  if (f_opendir(&d, dir) == FR_OK) {
-    while (f_readdir(&d, &fi) == FR_OK && fi.fname[0] != '\0') {
-      if (!strcmp(fi.fname, ".") || !strcmp(fi.fname, "..")) continue;
-      fn(fi.fname, userdata);
-    }
-    f_closedir(&d);
-  }
-}
+struct dns_data {
+  struct dns_data *next;
+  struct mg_connection *c;
+  uint64_t expire;
+  uint16_t txnid;
+};
 
-static void *ff_open(const char *path, int flags) {
-  FIL f;
-  unsigned char mode = FA_READ;
-  if (flags & MG_FS_WRITE) mode |= FA_WRITE | FA_OPEN_ALWAYS | FA_OPEN_APPEND;
-  if (f_open(&f, path, mode) == 0) {
-    FIL *fp = calloc(1, sizeof(*fp));
-    memcpy(fp, &f, sizeof(*fp));
-    return fp;
-  } else {
-    return NULL;
-  }
+static void mg_sendnsreq(struct mg_connection *, struct mg_str *, int,
+                         struct mg_dns *, bool);
+
+static void mg_dns_free(struct dns_data **head, struct dns_data *d) {
+  LIST_DELETE(struct dns_data, head, d);
+  free(d);
 }
 
-static void ff_close(void *fp) {
-  if (fp != NULL) {
-    f_close((FIL *) fp);
-    free(fp);
+void mg_resolve_cancel(struct mg_connection *c) {
+  struct dns_data *tmp, *d;
+  struct dns_data **head = (struct dns_data **) &c->mgr->active_dns_requests;
+  for (d = *head; d != NULL; d = tmp) {
+    tmp = d->next;
+    if (d->c == c) mg_dns_free(head, d);
   }
 }
 
-static size_t ff_read(void *fp, void *buf, size_t len) {
-  UINT n = 0, misalign = ((size_t) buf) & 3;
-  if (misalign) {
-    char aligned[4];
-    f_read((FIL *) fp, aligned, len > misalign ? misalign : len, &n);
-    memcpy(buf, aligned, n);
-  } else {
-    f_read((FIL *) fp, buf, len, &n);
+static size_t mg_dns_parse_name_depth(const uint8_t *s, size_t len, size_t ofs,
+                                      char *to, size_t tolen, size_t j,
+                                      int depth) {
+  size_t i = 0;
+  if (tolen > 0 && depth == 0) to[0] = '\0';
+  if (depth > 5) return 0;
+  // MG_INFO(("ofs %lx %x %x", (unsigned long) ofs, s[ofs], s[ofs + 1]));
+  while (ofs + i + 1 < len) {
+    size_t n = s[ofs + i];
+    if (n == 0) {
+      i++;
+      break;
+    }
+    if (n & 0xc0) {
+      size_t ptr = (((n & 0x3f) << 8) | s[ofs + i + 1]);  // 12 is hdr len
+      // MG_INFO(("PTR %lx", (unsigned long) ptr));
+      if (ptr + 1 < len && (s[ptr] & 0xc0) == 0 &&
+          mg_dns_parse_name_depth(s, len, ptr, to, tolen, j, depth + 1) == 0)
+        return 0;
+      i += 2;
+      break;
+    }
+    if (ofs + i + n + 1 >= len) return 0;
+    if (j > 0) {
+      if (j < tolen) to[j] = '.';
+      j++;
+    }
+    if (j + n < tolen) memcpy(&to[j], &s[ofs + i + 1], n);
+    j += n;
+    i += n + 1;
+    if (j < tolen) to[j] = '\0';  // Zero-terminate this chunk
+    // MG_INFO(("--> [%s]", to));
   }
-  return n;
+  if (tolen > 0) to[tolen - 1] = '\0';  // Make sure make sure it is nul-term
+  return i;
 }
 
-static size_t ff_write(void *fp, const void *buf, size_t len) {
-  UINT n = 0;
-  return f_write((FIL *) fp, (char *) buf, len, &n) == FR_OK ? n : 0;
+static size_t mg_dns_parse_name(const uint8_t *s, size_t n, size_t ofs,
+                                char *dst, size_t dstlen) {
+  return mg_dns_parse_name_depth(s, n, ofs, dst, dstlen, 0, 0);
 }
 
-static size_t ff_seek(void *fp, size_t offset) {
-  f_lseek((FIL *) fp, offset);
-  return offset;
+size_t mg_dns_parse_rr(const uint8_t *buf, size_t len, size_t ofs,
+                       bool is_question, struct mg_dns_rr *rr) {
+  const uint8_t *s = buf + ofs, *e = &buf[len];
+
+  memset(rr, 0, sizeof(*rr));
+  if (len < sizeof(struct mg_dns_header)) return 0;  // Too small
+  if (len > 512) return 0;  //  Too large, we don't expect that
+  if (s >= e) return 0;     //  Overflow
+
+  if ((rr->nlen = (uint16_t) mg_dns_parse_name(buf, len, ofs, NULL, 0)) == 0)
+    return 0;
+  s += rr->nlen + 4;
+  if (s > e) return 0;
+  rr->atype = (uint16_t) (((uint16_t) s[-4] << 8) | s[-3]);
+  rr->aclass = (uint16_t) (((uint16_t) s[-2] << 8) | s[-1]);
+  if (is_question) return (size_t) (rr->nlen + 4);
+
+  s += 6;
+  if (s > e) return 0;
+  rr->alen = (uint16_t) (((uint16_t) s[-2] << 8) | s[-1]);
+  if (s + rr->alen > e) return 0;
+  return (size_t) (rr->nlen + rr->alen + 10);
 }
 
-static bool ff_rename(const char *from, const char *to) {
-  return f_rename(from, to) == FR_OK;
+bool mg_dns_parse(const uint8_t *buf, size_t len, struct mg_dns_message *dm) {
+  const struct mg_dns_header *h = (struct mg_dns_header *) buf;
+  struct mg_dns_rr rr;
+  size_t i, n, num_answers, ofs = sizeof(*h);
+  memset(dm, 0, sizeof(*dm));
+
+  if (len < sizeof(*h)) return 0;                // Too small, headers dont fit
+  if (mg_ntohs(h->num_questions) > 1) return 0;  // Sanity
+  num_answers = mg_ntohs(h->num_answers);
+  if (num_answers > 10) {
+    MG_DEBUG(("Got %u answers, ignoring beyond 10th one", num_answers));
+    num_answers = 10;  // Sanity cap
+  }
+  dm->txnid = mg_ntohs(h->txnid);
+
+  for (i = 0; i < mg_ntohs(h->num_questions); i++) {
+    if ((n = mg_dns_parse_rr(buf, len, ofs, true, &rr)) == 0) return false;
+    // MG_INFO(("Q %lu %lu %hu/%hu", ofs, n, rr.atype, rr.aclass));
+    ofs += n;
+  }
+  for (i = 0; i < num_answers; i++) {
+    if ((n = mg_dns_parse_rr(buf, len, ofs, false, &rr)) == 0) return false;
+    // MG_INFO(("A -- %lu %lu %hu/%hu %s", ofs, n, rr.atype, rr.aclass,
+    // dm->name));
+    mg_dns_parse_name(buf, len, ofs, dm->name, sizeof(dm->name));
+    ofs += n;
+
+    if (rr.alen == 4 && rr.atype == 1 && rr.aclass == 1) {
+      dm->addr.is_ip6 = false;
+      memcpy(&dm->addr.ip, &buf[ofs - 4], 4);
+      dm->resolved = true;
+      break;  // Return success
+    } else if (rr.alen == 16 && rr.atype == 28 && rr.aclass == 1) {
+      dm->addr.is_ip6 = true;
+      memcpy(&dm->addr.ip, &buf[ofs - 16], 16);
+      dm->resolved = true;
+      break;  // Return success
+    }
+  }
+  return true;
 }
 
-static bool ff_remove(const char *path) {
-  return f_unlink(path) == FR_OK;
+static void dns_cb(struct mg_connection *c, int ev, void *ev_data) {
+  struct dns_data *d, *tmp;
+  struct dns_data **head = (struct dns_data **) &c->mgr->active_dns_requests;
+  if (ev == MG_EV_POLL) {
+    uint64_t now = *(uint64_t *) ev_data;
+    for (d = *head; d != NULL; d = tmp) {
+      tmp = d->next;
+      // MG_DEBUG ("%lu %lu dns poll", d->expire, now));
+      if (now > d->expire) mg_error(d->c, "DNS timeout");
+    }
+  } else if (ev == MG_EV_READ) {
+    struct mg_dns_message dm;
+    int resolved = 0;
+    if (mg_dns_parse(c->recv.buf, c->recv.len, &dm) == false) {
+      MG_ERROR(("Unexpected DNS response:"));
+      mg_hexdump(c->recv.buf, c->recv.len);
+    } else {
+      // MG_VERBOSE(("%s %d", dm.name, dm.resolved));
+      for (d = *head; d != NULL; d = tmp) {
+        tmp = d->next;
+        // MG_INFO(("d %p %hu %hu", d, d->txnid, dm.txnid));
+        if (dm.txnid != d->txnid) continue;
+        if (d->c->is_resolving) {
+          if (dm.resolved) {
+            dm.addr.port = d->c->rem.port;  // Save port
+            d->c->rem = dm.addr;            // Copy resolved address
+            MG_DEBUG(
+                ("%lu %s is %M", d->c->id, dm.name, mg_print_ip, &d->c->rem));
+            mg_connect_resolved(d->c);
+#if MG_ENABLE_IPV6
+          } else if (dm.addr.is_ip6 == false && dm.name[0] != '\0' &&
+                     c->mgr->use_dns6 == false) {
+            struct mg_str x = mg_str(dm.name);
+            mg_sendnsreq(d->c, &x, c->mgr->dnstimeout, &c->mgr->dns6, true);
+#endif
+          } else {
+            mg_error(d->c, "%s DNS lookup failed", dm.name);
+          }
+        } else {
+          MG_ERROR(("%lu already resolved", d->c->id));
+        }
+        mg_dns_free(head, d);
+        resolved = 1;
+      }
+    }
+    if (!resolved) MG_ERROR(("stray DNS reply"));
+    c->recv.len = 0;
+  } else if (ev == MG_EV_CLOSE) {
+    for (d = *head; d != NULL; d = tmp) {
+      tmp = d->next;
+      mg_error(d->c, "DNS error");
+      mg_dns_free(head, d);
+    }
+  }
 }
 
-static bool ff_mkdir(const char *path) {
-  return f_mkdir(path) == FR_OK;
+static bool mg_dns_send(struct mg_connection *c, const struct mg_str *name,
+                        uint16_t txnid, bool ipv6) {
+  struct {
+    struct mg_dns_header header;
+    uint8_t data[256];
+  } pkt;
+  size_t i, n;
+  memset(&pkt, 0, sizeof(pkt));
+  pkt.header.txnid = mg_htons(txnid);
+  pkt.header.flags = mg_htons(0x100);
+  pkt.header.num_questions = mg_htons(1);
+  for (i = n = 0; i < sizeof(pkt.data) - 5; i++) {
+    if (name->buf[i] == '.' || i >= name->len) {
+      pkt.data[n] = (uint8_t) (i - n);
+      memcpy(&pkt.data[n + 1], name->buf + n, i - n);
+      n = i + 1;
+    }
+    if (i >= name->len) break;
+  }
+  memcpy(&pkt.data[n], "\x00\x00\x01\x00\x01", 5);  // A query
+  n += 5;
+  if (ipv6) pkt.data[n - 3] = 0x1c;  // AAAA query
+  // memcpy(&pkt.data[n], "\xc0\x0c\x00\x1c\x00\x01", 6);  // AAAA query
+  // n += 6;
+  return mg_send(c, &pkt, sizeof(pkt.header) + n);
 }
 
-struct mg_fs mg_fs_fat = {ff_stat,  ff_list, ff_open,   ff_close,  ff_read,
-                          ff_write, ff_seek, ff_rename, ff_remove, ff_mkdir};
-#endif
+static void mg_sendnsreq(struct mg_connection *c, struct mg_str *name, int ms,
+                         struct mg_dns *dnsc, bool ipv6) {
+  struct dns_data *d = NULL;
+  if (dnsc->url == NULL) {
+    mg_error(c, "DNS server URL is NULL. Call mg_mgr_init()");
+  } else if (dnsc->c == NULL) {
+    dnsc->c = mg_connect(c->mgr, dnsc->url, NULL, NULL);
+    if (dnsc->c != NULL) {
+      dnsc->c->pfn = dns_cb;
+      // dnsc->c->is_hexdumping = 1;
+    }
+  }
+  if (dnsc->c == NULL) {
+    mg_error(c, "resolver");
+  } else if ((d = (struct dns_data *) calloc(1, sizeof(*d))) == NULL) {
+    mg_error(c, "resolve OOM");
+  } else {
+    struct dns_data *reqs = (struct dns_data *) c->mgr->active_dns_requests;
+    d->txnid = reqs ? (uint16_t) (reqs->txnid + 1) : 1;
+    d->next = (struct dns_data *) c->mgr->active_dns_requests;
+    c->mgr->active_dns_requests = d;
+    d->expire = mg_millis() + (uint64_t) ms;
+    d->c = c;
+    c->is_resolving = 1;
+    MG_VERBOSE(("%lu resolving %.*s @ %s, txnid %hu", c->id, (int) name->len,
+                name->buf, dnsc->url, d->txnid));
+    if (!mg_dns_send(dnsc->c, name, d->txnid, ipv6)) {
+      mg_error(dnsc->c, "DNS send");
+    }
+  }
+}
+
+void mg_resolve(struct mg_connection *c, const char *url) {
+  struct mg_str host = mg_url_host(url);
+  c->rem.port = mg_htons(mg_url_port(url));
+  if (mg_aton(host, &c->rem)) {
+    // host is an IP address, do not fire name resolution
+    mg_connect_resolved(c);
+  } else {
+    // host is not an IP, send DNS resolution request
+    struct mg_dns *dns = c->mgr->use_dns6 ? &c->mgr->dns6 : &c->mgr->dns4;
+    mg_sendnsreq(c, &host, c->mgr->dnstimeout, dns, c->mgr->use_dns6);
+  }
+}
 
 #ifdef MG_ENABLE_LINES
-#line 1 "src/fs_packed.c"
+#line 1 "src/event.c"
 #endif
 
 
 
 
-struct packed_file {
-  const char *data;
-  size_t size;
-  size_t pos;
-};
 
-const char *mg_unpack(const char *path, size_t *size, time_t *mtime);
-const char *mg_unlist(size_t no);
 
-#if MG_ENABLE_PACKED_FS
-#else
-const char *mg_unpack(const char *path, size_t *size, time_t *mtime) {
-  (void) path, (void) size, (void) mtime;
-  return NULL;
-}
-const char *mg_unlist(size_t no) {
-  (void) no;
-  return NULL;
-}
+void mg_call(struct mg_connection *c, int ev, void *ev_data) {
+#if MG_ENABLE_PROFILE
+  const char *names[] = {
+      "EV_ERROR",    "EV_OPEN",      "EV_POLL",      "EV_RESOLVE",
+      "EV_CONNECT",  "EV_ACCEPT",    "EV_TLS_HS",    "EV_READ",
+      "EV_WRITE",    "EV_CLOSE",     "EV_HTTP_MSG",  "EV_HTTP_CHUNK",
+      "EV_WS_OPEN",  "EV_WS_MSG",    "EV_WS_CTL",    "EV_MQTT_CMD",
+      "EV_MQTT_MSG", "EV_MQTT_OPEN", "EV_SNTP_TIME", "EV_USER"};
+  if (ev != MG_EV_POLL && ev < (int) (sizeof(names) / sizeof(names[0]))) {
+    MG_PROF_ADD(c, names[ev]);
+  }
 #endif
-
-static int is_dir_prefix(const char *prefix, size_t n, const char *path) {
-  // MG_INFO(("[%.*s] [%s] %c", (int) n, prefix, path, path[n]));
-  return n < strlen(path) && strncmp(prefix, path, n) == 0 &&
-         (n == 0 || path[n] == '/' || path[n - 1] == '/');
+  // Fire protocol handler first, user handler second. See #2559
+  if (c->pfn != NULL) c->pfn(c, ev, ev_data);
+  if (c->fn != NULL) c->fn(c, ev, ev_data);
 }
 
-static int packed_stat(const char *path, size_t *size, time_t *mtime) {
-  const char *p;
-  size_t i, n = strlen(path);
-  if (mg_unpack(path, size, mtime)) return MG_FS_READ;  // Regular file
-  // Scan all files. If `path` is a dir prefix for any of them, it's a dir
-  for (i = 0; (p = mg_unlist(i)) != NULL; i++) {
-    if (is_dir_prefix(path, n, p)) return MG_FS_DIR;
-  }
-  return 0;
-}
-
-static void packed_list(const char *dir, void (*fn)(const char *, void *),
-                        void *userdata) {
-  char buf[MG_PATH_MAX], tmp[sizeof(buf)];
-  const char *path, *begin, *end;
-  size_t i, n = strlen(dir);
-  tmp[0] = '\0';  // Previously listed entry
-  for (i = 0; (path = mg_unlist(i)) != NULL; i++) {
-    if (!is_dir_prefix(dir, n, path)) continue;
-    begin = &path[n + 1];
-    end = strchr(begin, '/');
-    if (end == NULL) end = begin + strlen(begin);
-    mg_snprintf(buf, sizeof(buf), "%.*s", (int) (end - begin), begin);
-    buf[sizeof(buf) - 1] = '\0';
-    // If this entry has been already listed, skip
-    // NOTE: we're assuming that file list is sorted alphabetically
-    if (strcmp(buf, tmp) == 0) continue;
-    fn(buf, userdata);  // Not yet listed, call user function
-    strcpy(tmp, buf);   // And save this entry as listed
-  }
-}
-
-static void *packed_open(const char *path, int flags) {
-  size_t size = 0;
-  const char *data = mg_unpack(path, &size, NULL);
-  struct packed_file *fp = NULL;
-  if (data == NULL) return NULL;
-  if (flags & MG_FS_WRITE) return NULL;
-  fp = (struct packed_file *) calloc(1, sizeof(*fp));
-  fp->size = size;
-  fp->data = data;
-  return (void *) fp;
+void mg_error(struct mg_connection *c, const char *fmt, ...) {
+  char buf[64];
+  va_list ap;
+  va_start(ap, fmt);
+  mg_vsnprintf(buf, sizeof(buf), fmt, &ap);
+  va_end(ap);
+  MG_ERROR(("%lu %ld %s", c->id, c->fd, buf));
+  c->is_closing = 1;             // Set is_closing before sending MG_EV_CALL
+  mg_call(c, MG_EV_ERROR, buf);  // Let user handler override it
 }
 
-static void packed_close(void *fp) {
-  if (fp != NULL) free(fp);
-}
+#ifdef MG_ENABLE_LINES
+#line 1 "src/fmt.c"
+#endif
 
-static size_t packed_read(void *fd, void *buf, size_t len) {
-  struct packed_file *fp = (struct packed_file *) fd;
-  if (fp->pos + len > fp->size) len = fp->size - fp->pos;
-  memcpy(buf, &fp->data[fp->pos], len);
-  fp->pos += len;
-  return len;
-}
 
-static size_t packed_write(void *fd, const void *buf, size_t len) {
-  (void) fd, (void) buf, (void) len;
-  return 0;
-}
 
-static size_t packed_seek(void *fd, size_t offset) {
-  struct packed_file *fp = (struct packed_file *) fd;
-  fp->pos = offset;
-  if (fp->pos > fp->size) fp->pos = fp->size;
-  return fp->pos;
-}
 
-static bool packed_rename(const char *from, const char *to) {
-  (void) from, (void) to;
-  return false;
+static bool is_digit(int c) {
+  return c >= '0' && c <= '9';
 }
 
-static bool packed_remove(const char *path) {
-  (void) path;
-  return false;
+static int addexp(char *buf, int e, int sign) {
+  int n = 0;
+  buf[n++] = 'e';
+  buf[n++] = (char) sign;
+  if (e > 400) return 0;
+  if (e < 10) buf[n++] = '0';
+  if (e >= 100) buf[n++] = (char) (e / 100 + '0'), e -= 100 * (e / 100);
+  if (e >= 10) buf[n++] = (char) (e / 10 + '0'), e -= 10 * (e / 10);
+  buf[n++] = (char) (e + '0');
+  return n;
 }
 
-static bool packed_mkdir(const char *path) {
-  (void) path;
-  return false;
+static int xisinf(double x) {
+  union {
+    double f;
+    uint64_t u;
+  } ieee754 = {x};
+  return ((unsigned) (ieee754.u >> 32) & 0x7fffffff) == 0x7ff00000 &&
+         ((unsigned) ieee754.u == 0);
 }
 
-struct mg_fs mg_fs_packed = {
-    packed_stat,  packed_list, packed_open,   packed_close,  packed_read,
-    packed_write, packed_seek, packed_rename, packed_remove, packed_mkdir};
-
-#ifdef MG_ENABLE_LINES
-#line 1 "src/fs_posix.c"
-#endif
-
-
-#if MG_ENABLE_FILE
-
-#ifndef MG_STAT_STRUCT
-#define MG_STAT_STRUCT stat
-#endif
-
-#ifndef MG_STAT_FUNC
-#define MG_STAT_FUNC stat
-#endif
-
-static int p_stat(const char *path, size_t *size, time_t *mtime) {
-#if !defined(S_ISDIR)
-  MG_ERROR(("stat() API is not supported. %p %p %p", path, size, mtime));
-  return 0;
-#else
-#if MG_ARCH == MG_ARCH_WIN32
-  struct _stati64 st;
-  wchar_t tmp[MG_PATH_MAX];
-  MultiByteToWideChar(CP_UTF8, 0, path, -1, tmp, sizeof(tmp) / sizeof(tmp[0]));
-  if (_wstati64(tmp, &st) != 0) return 0;
-#else
-  struct MG_STAT_STRUCT st;
-  if (MG_STAT_FUNC(path, &st) != 0) return 0;
-#endif
-  if (size) *size = (size_t) st.st_size;
-  if (mtime) *mtime = st.st_mtime;
-  return MG_FS_READ | MG_FS_WRITE | (S_ISDIR(st.st_mode) ? MG_FS_DIR : 0);
-#endif
+static int xisnan(double x) {
+  union {
+    double f;
+    uint64_t u;
+  } ieee754 = {x};
+  return ((unsigned) (ieee754.u >> 32) & 0x7fffffff) +
+             ((unsigned) ieee754.u != 0) >
+         0x7ff00000;
 }
 
-#if MG_ARCH == MG_ARCH_WIN32
-struct dirent {
-  char d_name[MAX_PATH];
-};
-
-typedef struct win32_dir {
-  HANDLE handle;
-  WIN32_FIND_DATAW info;
-  struct dirent result;
-} DIR;
+static size_t mg_dtoa(char *dst, size_t dstlen, double d, int width, bool tz) {
+  char buf[40];
+  int i, s = 0, n = 0, e = 0;
+  double t, mul, saved;
+  if (d == 0.0) return mg_snprintf(dst, dstlen, "%s", "0");
+  if (xisinf(d)) return mg_snprintf(dst, dstlen, "%s", d > 0 ? "inf" : "-inf");
+  if (xisnan(d)) return mg_snprintf(dst, dstlen, "%s", "nan");
+  if (d < 0.0) d = -d, buf[s++] = '-';
 
-int gettimeofday(struct timeval *tv, void *tz) {
-  FILETIME ft;
-  unsigned __int64 tmpres = 0;
+  // Round
+  saved = d;
+  mul = 1.0;
+  while (d >= 10.0 && d / mul >= 10.0) mul *= 10.0;
+  while (d <= 1.0 && d / mul <= 1.0) mul /= 10.0;
+  for (i = 0, t = mul * 5; i < width; i++) t /= 10.0;
+  d += t;
+  // Calculate exponent, and 'mul' for scientific representation
+  mul = 1.0;
+  while (d >= 10.0 && d / mul >= 10.0) mul *= 10.0, e++;
+  while (d < 1.0 && d / mul < 1.0) mul /= 10.0, e--;
+  // printf(" --> %g %d %g %g\n", saved, e, t, mul);
 
-  if (tv != NULL) {
-    GetSystemTimeAsFileTime(&ft);
-    tmpres |= ft.dwHighDateTime;
-    tmpres <<= 32;
-    tmpres |= ft.dwLowDateTime;
-    tmpres /= 10;  // convert into microseconds
-    tmpres -= (int64_t) 11644473600000000;
-    tv->tv_sec = (long) (tmpres / 1000000UL);
-    tv->tv_usec = (long) (tmpres % 1000000UL);
+  if (e >= width && width > 1) {
+    n = (int) mg_dtoa(buf, sizeof(buf), saved / mul, width, tz);
+    // printf(" --> %.*g %d [%.*s]\n", 10, d / t, e, n, buf);
+    n += addexp(buf + s + n, e, '+');
+    return mg_snprintf(dst, dstlen, "%.*s", n, buf);
+  } else if (e <= -width && width > 1) {
+    n = (int) mg_dtoa(buf, sizeof(buf), saved / mul, width, tz);
+    // printf(" --> %.*g %d [%.*s]\n", 10, d / mul, e, n, buf);
+    n += addexp(buf + s + n, -e, '-');
+    return mg_snprintf(dst, dstlen, "%.*s", n, buf);
+  } else {
+    for (i = 0, t = mul; t >= 1.0 && s + n < (int) sizeof(buf); i++) {
+      int ch = (int) (d / t);
+      if (n > 0 || ch > 0) buf[s + n++] = (char) (ch + '0');
+      d -= ch * t;
+      t /= 10.0;
+    }
+    // printf(" --> [%g] -> %g %g (%d) [%.*s]\n", saved, d, t, n, s + n, buf);
+    if (n == 0) buf[s++] = '0';
+    while (t >= 1.0 && n + s < (int) sizeof(buf)) buf[n++] = '0', t /= 10.0;
+    if (s + n < (int) sizeof(buf)) buf[n + s++] = '.';
+    // printf(" 1--> [%g] -> [%.*s]\n", saved, s + n, buf);
+    for (i = 0, t = 0.1; s + n < (int) sizeof(buf) && n < width; i++) {
+      int ch = (int) (d / t);
+      buf[s + n++] = (char) (ch + '0');
+      d -= ch * t;
+      t /= 10.0;
+    }
   }
-  (void) tz;
-  return 0;
+  while (tz && n > 0 && buf[s + n - 1] == '0') n--;  // Trim trailing zeroes
+  if (n > 0 && buf[s + n - 1] == '.') n--;           // Trim trailing dot
+  n += s;
+  if (n >= (int) sizeof(buf)) n = (int) sizeof(buf) - 1;
+  buf[n] = '\0';
+  return mg_snprintf(dst, dstlen, "%s", buf);
 }
 
-static int to_wchar(const char *path, wchar_t *wbuf, size_t wbuf_len) {
-  int ret;
-  char buf[MAX_PATH * 2], buf2[MAX_PATH * 2], *p;
-  strncpy(buf, path, sizeof(buf));
-  buf[sizeof(buf) - 1] = '\0';
-  // Trim trailing slashes. Leave backslash for paths like "X:\"
-  p = buf + strlen(buf) - 1;
-  while (p > buf && p[-1] != ':' && (p[0] == '\\' || p[0] == '/')) *p-- = '\0';
-  memset(wbuf, 0, wbuf_len * sizeof(wchar_t));
-  ret = MultiByteToWideChar(CP_UTF8, 0, buf, -1, wbuf, (int) wbuf_len);
-  // Convert back to Unicode. If doubly-converted string does not match the
-  // original, something is fishy, reject.
-  WideCharToMultiByte(CP_UTF8, 0, wbuf, (int) wbuf_len, buf2, sizeof(buf2),
-                      NULL, NULL);
-  if (strcmp(buf, buf2) != 0) {
-    wbuf[0] = L'\0';
-    ret = 0;
+static size_t mg_lld(char *buf, int64_t val, bool is_signed, bool is_hex) {
+  const char *letters = "0123456789abcdef";
+  uint64_t v = (uint64_t) val;
+  size_t s = 0, n, i;
+  if (is_signed && val < 0) buf[s++] = '-', v = (uint64_t) (-val);
+  // This loop prints a number in reverse order. I guess this is because we
+  // write numbers from right to left: least significant digit comes last.
+  // Maybe because we use Arabic numbers, and Arabs write RTL?
+  if (is_hex) {
+    for (n = 0; v; v >>= 4) buf[s + n++] = letters[v & 15];
+  } else {
+    for (n = 0; v; v /= 10) buf[s + n++] = letters[v % 10];
   }
-  return ret;
+  // Reverse a string
+  for (i = 0; i < n / 2; i++) {
+    char t = buf[s + i];
+    buf[s + i] = buf[s + n - i - 1], buf[s + n - i - 1] = t;
+  }
+  if (val == 0) buf[n++] = '0';  // Handle special case
+  return n + s;
 }
 
-DIR *opendir(const char *name) {
-  DIR *d = NULL;
-  wchar_t wpath[MAX_PATH];
-  DWORD attrs;
+static size_t scpy(void (*out)(char, void *), void *ptr, char *buf,
+                          size_t len) {
+  size_t i = 0;
+  while (i < len && buf[i] != '\0') out(buf[i++], ptr);
+  return i;
+}
 
-  if (name == NULL) {
-    SetLastError(ERROR_BAD_ARGUMENTS);
-  } else if ((d = (DIR *) calloc(1, sizeof(*d))) == NULL) {
-    SetLastError(ERROR_NOT_ENOUGH_MEMORY);
-  } else {
-    to_wchar(name, wpath, sizeof(wpath) / sizeof(wpath[0]));
-    attrs = GetFileAttributesW(wpath);
-    if (attrs != 0Xffffffff && (attrs & FILE_ATTRIBUTE_DIRECTORY)) {
-      (void) wcscat(wpath, L"\\*");
-      d->handle = FindFirstFileW(wpath, &d->info);
-      d->result.d_name[0] = '\0';
+size_t mg_xprintf(void (*out)(char, void *), void *ptr, const char *fmt, ...) {
+  size_t len = 0;
+  va_list ap;
+  va_start(ap, fmt);
+  len = mg_vxprintf(out, ptr, fmt, &ap);
+  va_end(ap);
+  return len;
+}
+
+size_t mg_vxprintf(void (*out)(char, void *), void *param, const char *fmt,
+                   va_list *ap) {
+  size_t i = 0, n = 0;
+  while (fmt[i] != '\0') {
+    if (fmt[i] == '%') {
+      size_t j, k, x = 0, is_long = 0, w = 0 /* width */, pr = ~0U /* prec */;
+      char pad = ' ', minus = 0, c = fmt[++i];
+      if (c == '#') x++, c = fmt[++i];
+      if (c == '-') minus++, c = fmt[++i];
+      if (c == '0') pad = '0', c = fmt[++i];
+      while (is_digit(c)) w *= 10, w += (size_t) (c - '0'), c = fmt[++i];
+      if (c == '.') {
+        c = fmt[++i];
+        if (c == '*') {
+          pr = (size_t) va_arg(*ap, int);
+          c = fmt[++i];
+        } else {
+          pr = 0;
+          while (is_digit(c)) pr *= 10, pr += (size_t) (c - '0'), c = fmt[++i];
+        }
+      }
+      while (c == 'h') c = fmt[++i];  // Treat h and hh as int
+      if (c == 'l') {
+        is_long++, c = fmt[++i];
+        if (c == 'l') is_long++, c = fmt[++i];
+      }
+      if (c == 'p') x = 1, is_long = 1;
+      if (c == 'd' || c == 'u' || c == 'x' || c == 'X' || c == 'p' ||
+          c == 'g' || c == 'f') {
+        bool s = (c == 'd'), h = (c == 'x' || c == 'X' || c == 'p');
+        char tmp[40];
+        size_t xl = x ? 2 : 0;
+        if (c == 'g' || c == 'f') {
+          double v = va_arg(*ap, double);
+          if (pr == ~0U) pr = 6;
+          k = mg_dtoa(tmp, sizeof(tmp), v, (int) pr, c == 'g');
+        } else if (is_long == 2) {
+          int64_t v = va_arg(*ap, int64_t);
+          k = mg_lld(tmp, v, s, h);
+        } else if (is_long == 1) {
+          long v = va_arg(*ap, long);
+          k = mg_lld(tmp, s ? (int64_t) v : (int64_t) (unsigned long) v, s, h);
+        } else {
+          int v = va_arg(*ap, int);
+          k = mg_lld(tmp, s ? (int64_t) v : (int64_t) (unsigned) v, s, h);
+        }
+        for (j = 0; j < xl && w > 0; j++) w--;
+        for (j = 0; pad == ' ' && !minus && k < w && j + k < w; j++)
+          n += scpy(out, param, &pad, 1);
+        n += scpy(out, param, (char *) "0x", xl);
+        for (j = 0; pad == '0' && k < w && j + k < w; j++)
+          n += scpy(out, param, &pad, 1);
+        n += scpy(out, param, tmp, k);
+        for (j = 0; pad == ' ' && minus && k < w && j + k < w; j++)
+          n += scpy(out, param, &pad, 1);
+      } else if (c == 'm' || c == 'M') {
+        mg_pm_t f = va_arg(*ap, mg_pm_t);
+        if (c == 'm') out('"', param);
+        n += f(out, param, ap);
+        if (c == 'm') n += 2, out('"', param);
+      } else if (c == 'c') {
+        int ch = va_arg(*ap, int);
+        out((char) ch, param);
+        n++;
+      } else if (c == 's') {
+        char *p = va_arg(*ap, char *);
+        if (pr == ~0U) pr = p == NULL ? 0 : strlen(p);
+        for (j = 0; !minus && pr < w && j + pr < w; j++)
+          n += scpy(out, param, &pad, 1);
+        n += scpy(out, param, p, pr);
+        for (j = 0; minus && pr < w && j + pr < w; j++)
+          n += scpy(out, param, &pad, 1);
+      } else if (c == '%') {
+        out('%', param);
+        n++;
+      } else {
+        out('%', param);
+        out(c, param);
+        n += 2;
+      }
+      i++;
     } else {
-      free(d);
-      d = NULL;
+      out(fmt[i], param), n++, i++;
     }
   }
-  return d;
+  return n;
 }
 
-int closedir(DIR *d) {
-  int result = 0;
-  if (d != NULL) {
-    if (d->handle != INVALID_HANDLE_VALUE)
-      result = FindClose(d->handle) ? 0 : -1;
-    free(d);
-  } else {
-    result = -1;
-    SetLastError(ERROR_BAD_ARGUMENTS);
+#ifdef MG_ENABLE_LINES
+#line 1 "src/fs.c"
+#endif
+
+
+
+
+struct mg_fd *mg_fs_open(struct mg_fs *fs, const char *path, int flags) {
+  struct mg_fd *fd = (struct mg_fd *) calloc(1, sizeof(*fd));
+  if (fd != NULL) {
+    fd->fd = fs->op(path, flags);
+    fd->fs = fs;
+    if (fd->fd == NULL) {
+      free(fd);
+      fd = NULL;
+    }
   }
-  return result;
+  return fd;
 }
 
-struct dirent *readdir(DIR *d) {
-  struct dirent *result = NULL;
-  if (d != NULL) {
-    memset(&d->result, 0, sizeof(d->result));
-    if (d->handle != INVALID_HANDLE_VALUE) {
-      result = &d->result;
-      WideCharToMultiByte(CP_UTF8, 0, d->info.cFileName, -1, result->d_name,
-                          sizeof(result->d_name), NULL, NULL);
-      if (!FindNextFileW(d->handle, &d->info)) {
-        FindClose(d->handle);
-        d->handle = INVALID_HANDLE_VALUE;
-      }
-    } else {
-      SetLastError(ERROR_FILE_NOT_FOUND);
-    }
-  } else {
-    SetLastError(ERROR_BAD_ARGUMENTS);
+void mg_fs_close(struct mg_fd *fd) {
+  if (fd != NULL) {
+    fd->fs->cl(fd->fd);
+    free(fd);
   }
-  return result;
 }
-#endif
 
-static void p_list(const char *dir, void (*fn)(const char *, void *),
-                   void *userdata) {
-#if MG_ENABLE_DIRLIST
-  struct dirent *dp;
-  DIR *dirp;
-  if ((dirp = (opendir(dir))) == NULL) return;
-  while ((dp = readdir(dirp)) != NULL) {
-    if (!strcmp(dp->d_name, ".") || !strcmp(dp->d_name, "..")) continue;
-    fn(dp->d_name, userdata);
+struct mg_str mg_file_read(struct mg_fs *fs, const char *path) {
+  struct mg_str result = {NULL, 0};
+  void *fp;
+  fs->st(path, &result.len, NULL);
+  if ((fp = fs->op(path, MG_FS_READ)) != NULL) {
+    result.buf = (char *) calloc(1, result.len + 1);
+    if (result.buf != NULL &&
+        fs->rd(fp, (void *) result.buf, result.len) != result.len) {
+      free((void *) result.buf);
+      result.buf = NULL;
+    }
+    fs->cl(fp);
   }
-  closedir(dirp);
-#else
-  (void) dir, (void) fn, (void) userdata;
-#endif
+  if (result.buf == NULL) result.len = 0;
+  return result;
 }
 
-static void *p_open(const char *path, int flags) {
-  const char *mode = flags == MG_FS_READ ? "rb" : "a+b";
-#if MG_ARCH == MG_ARCH_WIN32
-  wchar_t b1[MG_PATH_MAX], b2[10];
-  MultiByteToWideChar(CP_UTF8, 0, path, -1, b1, sizeof(b1) / sizeof(b1[0]));
-  MultiByteToWideChar(CP_UTF8, 0, mode, -1, b2, sizeof(b2) / sizeof(b2[0]));
-  return (void *) _wfopen(b1, b2);
-#else
-  return (void *) fopen(path, mode);
-#endif
+bool mg_file_write(struct mg_fs *fs, const char *path, const void *buf,
+                   size_t len) {
+  bool result = false;
+  struct mg_fd *fd;
+  char tmp[MG_PATH_MAX];
+  mg_snprintf(tmp, sizeof(tmp), "%s..%d", path, rand());
+  if ((fd = mg_fs_open(fs, tmp, MG_FS_WRITE)) != NULL) {
+    result = fs->wr(fd->fd, buf, len) == len;
+    mg_fs_close(fd);
+    if (result) {
+      fs->rm(path);
+      fs->mv(tmp, path);
+    } else {
+      fs->rm(tmp);
+    }
+  }
+  return result;
 }
 
-static void p_close(void *fp) {
-  fclose((FILE *) fp);
+bool mg_file_printf(struct mg_fs *fs, const char *path, const char *fmt, ...) {
+  va_list ap;
+  char *data;
+  bool result = false;
+  va_start(ap, fmt);
+  data = mg_vmprintf(fmt, &ap);
+  va_end(ap);
+  result = mg_file_write(fs, path, data, strlen(data));
+  free(data);
+  return result;
 }
 
-static size_t p_read(void *fp, void *buf, size_t len) {
-  return fread(buf, 1, len, (FILE *) fp);
+// This helper function allows to scan a filesystem in a sequential way,
+// without using callback function:
+//      char buf[100] = "";
+//      while (mg_fs_ls(&mg_fs_posix, "./", buf, sizeof(buf))) {
+//        ...
+static void mg_fs_ls_fn(const char *filename, void *param) {
+  struct mg_str *s = (struct mg_str *) param;
+  if (s->buf[0] == '\0') {
+    mg_snprintf((char *) s->buf, s->len, "%s", filename);
+  } else if (strcmp(s->buf, filename) == 0) {
+    ((char *) s->buf)[0] = '\0';  // Fetch next file
+  }
 }
 
-static size_t p_write(void *fp, const void *buf, size_t len) {
-  return fwrite(buf, 1, len, (FILE *) fp);
+bool mg_fs_ls(struct mg_fs *fs, const char *path, char *buf, size_t len) {
+  struct mg_str s = {buf, len};
+  fs->ls(path, mg_fs_ls_fn, &s);
+  return buf[0] != '\0';
 }
 
-static size_t p_seek(void *fp, size_t offset) {
-#if (defined(_FILE_OFFSET_BITS) && _FILE_OFFSET_BITS == 64) ||  \
-    (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L) || \
-    (defined(_XOPEN_SOURCE) && _XOPEN_SOURCE >= 600)
-  if (fseeko((FILE *) fp, (off_t) offset, SEEK_SET) != 0) (void) 0;
-#else
-  if (fseek((FILE *) fp, (long) offset, SEEK_SET) != 0) (void) 0;
+#ifdef MG_ENABLE_LINES
+#line 1 "src/fs_fat.c"
 #endif
-  return (size_t) ftell((FILE *) fp);
-}
 
-static bool p_rename(const char *from, const char *to) {
-  return rename(from, to) == 0;
-}
 
-static bool p_remove(const char *path) {
-  return remove(path) == 0;
-}
 
-static bool p_mkdir(const char *path) {
-  return mkdir(path, 0775) == 0;
-}
+#if MG_ENABLE_FATFS
+#include <ff.h>
 
-#else
+static int mg_days_from_epoch(int y, int m, int d) {
+  y -= m <= 2;
+  int era = y / 400;
+  int yoe = y - era * 400;
+  int doy = (153 * (m + (m > 2 ? -3 : 9)) + 2) / 5 + d - 1;
+  int doe = yoe * 365 + yoe / 4 - yoe / 100 + doy;
+  return era * 146097 + doe - 719468;
+}
 
-static int p_stat(const char *path, size_t *size, time_t *mtime) {
-  (void) path, (void) size, (void) mtime;
-  return 0;
+static time_t mg_timegm(const struct tm *t) {
+  int year = t->tm_year + 1900;
+  int month = t->tm_mon;  // 0-11
+  if (month > 11) {
+    year += month / 12;
+    month %= 12;
+  } else if (month < 0) {
+    int years_diff = (11 - month) / 12;
+    year -= years_diff;
+    month += 12 * years_diff;
+  }
+  int x = mg_days_from_epoch(year, month + 1, t->tm_mday);
+  return 60 * (60 * (24L * x + t->tm_hour) + t->tm_min) + t->tm_sec;
 }
-static void p_list(const char *path, void (*fn)(const char *, void *),
-                   void *userdata) {
-  (void) path, (void) fn, (void) userdata;
-}
-static void *p_open(const char *path, int flags) {
-  (void) path, (void) flags;
-  return NULL;
-}
-static void p_close(void *fp) {
-  (void) fp;
-}
-static size_t p_read(void *fd, void *buf, size_t len) {
-  (void) fd, (void) buf, (void) len;
-  return 0;
-}
-static size_t p_write(void *fd, const void *buf, size_t len) {
-  (void) fd, (void) buf, (void) len;
-  return 0;
-}
-static size_t p_seek(void *fd, size_t offset) {
-  (void) fd, (void) offset;
-  return (size_t) ~0;
-}
-static bool p_rename(const char *from, const char *to) {
-  (void) from, (void) to;
-  return false;
-}
-static bool p_remove(const char *path) {
-  (void) path;
-  return false;
-}
-static bool p_mkdir(const char *path) {
-  (void) path;
-  return false;
-}
-#endif
-
-struct mg_fs mg_fs_posix = {p_stat,  p_list, p_open,   p_close,  p_read,
-                            p_write, p_seek, p_rename, p_remove, p_mkdir};
-
-#ifdef MG_ENABLE_LINES
-#line 1 "src/http.c"
-#endif
-
-
-
-
-
-
-
-
-
-
-
-
-// Chunk deletion marker is the MSB in the "processed" counter
-#define MG_DMARK ((size_t) 1 << (sizeof(size_t) * 8 - 1))
-
-// Multipart POST example:
-// --xyz
-// Content-Disposition: form-data; name="val"
-//
-// abcdef
-// --xyz
-// Content-Disposition: form-data; name="foo"; filename="a.txt"
-// Content-Type: text/plain
-//
-// hello world
-//
-// --xyz--
-size_t mg_http_next_multipart(struct mg_str body, size_t ofs,
-                              struct mg_http_part *part) {
-  struct mg_str cd = mg_str_n("Content-Disposition", 19);
-  const char *s = body.ptr;
-  size_t b = ofs, h1, h2, b1, b2, max = body.len;
-
-  // Init part params
-  if (part != NULL) part->name = part->filename = part->body = mg_str_n(0, 0);
-
-  // Skip boundary
-  while (b + 2 < max && s[b] != '\r' && s[b + 1] != '\n') b++;
-  if (b <= ofs || b + 2 >= max) return 0;
-  // MG_INFO(("B: %zu %zu [%.*s]", ofs, b - ofs, (int) (b - ofs), s));
-
-  // Skip headers
-  h1 = h2 = b + 2;
-  for (;;) {
-    while (h2 + 2 < max && s[h2] != '\r' && s[h2 + 1] != '\n') h2++;
-    if (h2 == h1) break;
-    if (h2 + 2 >= max) return 0;
-    // MG_INFO(("Header: [%.*s]", (int) (h2 - h1), &s[h1]));
-    if (part != NULL && h1 + cd.len + 2 < h2 && s[h1 + cd.len] == ':' &&
-        mg_ncasecmp(&s[h1], cd.ptr, cd.len) == 0) {
-      struct mg_str v = mg_str_n(&s[h1 + cd.len + 2], h2 - (h1 + cd.len + 2));
-      part->name = mg_http_get_header_var(v, mg_str_n("name", 4));
-      part->filename = mg_http_get_header_var(v, mg_str_n("filename", 8));
-    }
-    h1 = h2 = h2 + 2;
-  }
-  b1 = b2 = h2 + 2;
-  while (b2 + 2 + (b - ofs) + 2 < max && !(s[b2] == '\r' && s[b2 + 1] == '\n' &&
-                                           memcmp(&s[b2 + 2], s, b - ofs) == 0))
-    b2++;
 
-  if (b2 + 2 >= max) return 0;
-  if (part != NULL) part->body = mg_str_n(&s[b1], b2 - b1);
-  // MG_INFO(("Body: [%.*s]", (int) (b2 - b1), &s[b1]));
-  return b2 + 2;
+static time_t ff_time_to_epoch(uint16_t fdate, uint16_t ftime) {
+  struct tm tm;
+  memset(&tm, 0, sizeof(struct tm));
+  tm.tm_sec = (ftime << 1) & 0x3e;
+  tm.tm_min = ((ftime >> 5) & 0x3f);
+  tm.tm_hour = ((ftime >> 11) & 0x1f);
+  tm.tm_mday = (fdate & 0x1f);
+  tm.tm_mon = ((fdate >> 5) & 0x0f) - 1;
+  tm.tm_year = ((fdate >> 9) & 0x7f) + 80;
+  return mg_timegm(&tm);
 }
 
-void mg_http_bauth(struct mg_connection *c, const char *user,
-                   const char *pass) {
-  struct mg_str u = mg_str(user), p = mg_str(pass);
-  size_t need = c->send.len + 36 + (u.len + p.len) * 2;
-  if (c->send.size < need) mg_iobuf_resize(&c->send, need);
-  if (c->send.size >= need) {
-    int i, n = 0;
-    char *buf = (char *) &c->send.buf[c->send.len];
-    memcpy(buf, "Authorization: Basic ", 21);  // DON'T use mg_send!
-    for (i = 0; i < (int) u.len; i++) {
-      n = mg_base64_update(((unsigned char *) u.ptr)[i], buf + 21, n);
-    }
-    if (p.len > 0) {
-      n = mg_base64_update(':', buf + 21, n);
-      for (i = 0; i < (int) p.len; i++) {
-        n = mg_base64_update(((unsigned char *) p.ptr)[i], buf + 21, n);
-      }
-    }
-    n = mg_base64_final(buf + 21, n);
-    c->send.len += 21 + (size_t) n + 2;
-    memcpy(&c->send.buf[c->send.len - 2], "\r\n", 2);
+static int ff_stat(const char *path, size_t *size, time_t *mtime) {
+  FILINFO fi;
+  if (path[0] == '\0') {
+    if (size) *size = 0;
+    if (mtime) *mtime = 0;
+    return MG_FS_DIR;
+  } else if (f_stat(path, &fi) == 0) {
+    if (size) *size = (size_t) fi.fsize;
+    if (mtime) *mtime = ff_time_to_epoch(fi.fdate, fi.ftime);
+    return MG_FS_READ | MG_FS_WRITE | ((fi.fattrib & AM_DIR) ? MG_FS_DIR : 0);
   } else {
-    MG_ERROR(("%lu oom %d->%d ", c->id, (int) c->send.size, (int) need));
+    return 0;
   }
 }
 
-struct mg_str mg_http_var(struct mg_str buf, struct mg_str name) {
-  struct mg_str k, v, result = mg_str_n(NULL, 0);
-  while (mg_split(&buf, &k, &v, '&')) {
-    if (name.len == k.len && mg_ncasecmp(name.ptr, k.ptr, k.len) == 0) {
-      result = v;
-      break;
+static void ff_list(const char *dir, void (*fn)(const char *, void *),
+                    void *userdata) {
+  DIR d;
+  FILINFO fi;
+  if (f_opendir(&d, dir) == FR_OK) {
+    while (f_readdir(&d, &fi) == FR_OK && fi.fname[0] != '\0') {
+      if (!strcmp(fi.fname, ".") || !strcmp(fi.fname, "..")) continue;
+      fn(fi.fname, userdata);
     }
+    f_closedir(&d);
   }
-  return result;
 }
 
-int mg_http_get_var(const struct mg_str *buf, const char *name, char *dst,
-                    size_t dst_len) {
-  int len;
-  if (dst == NULL || dst_len == 0) {
-    len = -2;  // Bad destination
-  } else if (buf->ptr == NULL || name == NULL || buf->len == 0) {
-    len = -1;  // Bad source
-    dst[0] = '\0';
-  } else {
-    struct mg_str v = mg_http_var(*buf, mg_str(name));
-    if (v.ptr == NULL) {
-      len = -4;  // Name does not exist
-    } else {
-      len = mg_url_decode(v.ptr, v.len, dst, dst_len, 1);
-      if (len < 0) len = -3;  // Failed to decode
+static void *ff_open(const char *path, int flags) {
+  FIL f;
+  unsigned char mode = FA_READ;
+  if (flags & MG_FS_WRITE) mode |= FA_WRITE | FA_OPEN_ALWAYS | FA_OPEN_APPEND;
+  if (f_open(&f, path, mode) == 0) {
+    FIL *fp;
+    if ((fp = calloc(1, sizeof(*fp))) != NULL) {
+      memcpy(fp, &f, sizeof(*fp));
+      return fp;
     }
   }
-  return len;
+  return NULL;
 }
 
-static bool isx(int c) {
-  return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') ||
-         (c >= 'A' && c <= 'F');
+static void ff_close(void *fp) {
+  if (fp != NULL) {
+    f_close((FIL *) fp);
+    free(fp);
+  }
 }
 
-int mg_url_decode(const char *src, size_t src_len, char *dst, size_t dst_len,
-                  int is_form_url_encoded) {
-  size_t i, j;
-  for (i = j = 0; i < src_len && j + 1 < dst_len; i++, j++) {
-    if (src[i] == '%') {
-      // Use `i + 2 < src_len`, not `i < src_len - 2`, note small src_len
-      if (i + 2 < src_len && isx(src[i + 1]) && isx(src[i + 2])) {
-        mg_unhex(src + i + 1, 2, (uint8_t *) &dst[j]);
-        i += 2;
-      } else {
-        return -1;
-      }
-    } else if (is_form_url_encoded && src[i] == '+') {
-      dst[j] = ' ';
-    } else {
-      dst[j] = src[i];
-    }
+static size_t ff_read(void *fp, void *buf, size_t len) {
+  UINT n = 0, misalign = ((size_t) buf) & 3;
+  if (misalign) {
+    char aligned[4];
+    f_read((FIL *) fp, aligned, len > misalign ? misalign : len, &n);
+    memcpy(buf, aligned, n);
+  } else {
+    f_read((FIL *) fp, buf, len, &n);
   }
-  if (j < dst_len) dst[j] = '\0';  // Null-terminate the destination
-  return i >= src_len && j < dst_len ? (int) j : -1;
+  return n;
 }
 
-static bool isok(uint8_t c) { return c == '\n' || c == '\r' || c >= ' '; }
-
-int mg_http_get_request_len(const unsigned char *buf, size_t buf_len) {
-  size_t i;
-  for (i = 0; i < buf_len; i++) {
-    if (!isok(buf[i])) return -1;
-    if ((i > 0 && buf[i] == '\n' && buf[i - 1] == '\n') ||
-        (i > 3 && buf[i] == '\n' && buf[i - 1] == '\r' && buf[i - 2] == '\n'))
-      return (int) i + 1;
-  }
-  return 0;
+static size_t ff_write(void *fp, const void *buf, size_t len) {
+  UINT n = 0;
+  return f_write((FIL *) fp, (char *) buf, len, &n) == FR_OK ? n : 0;
 }
 
-static const char *skip(const char *s, const char *e, const char *d,
-                        struct mg_str *v) {
-  v->ptr = s;
-  while (s < e && *s != '\n' && strchr(d, *s) == NULL) s++;
-  v->len = (size_t) (s - v->ptr);
-  while (s < e && strchr(d, *s) != NULL) s++;
-  return s;
+static size_t ff_seek(void *fp, size_t offset) {
+  f_lseek((FIL *) fp, offset);
+  return offset;
 }
 
-struct mg_str *mg_http_get_header(struct mg_http_message *h, const char *name) {
-  size_t i, n = strlen(name), max = sizeof(h->headers) / sizeof(h->headers[0]);
-  for (i = 0; i < max && h->headers[i].name.len > 0; i++) {
-    struct mg_str *k = &h->headers[i].name, *v = &h->headers[i].value;
-    if (n == k->len && mg_ncasecmp(k->ptr, name, n) == 0) return v;
-  }
-  return NULL;
+static bool ff_rename(const char *from, const char *to) {
+  return f_rename(from, to) == FR_OK;
 }
 
-static void mg_http_parse_headers(const char *s, const char *end,
-                                  struct mg_http_header *h, int max_headers) {
-  int i;
-  for (i = 0; i < max_headers; i++) {
-    struct mg_str k, v, tmp;
-    const char *he = skip(s, end, "\n", &tmp);
-    s = skip(s, he, ": \r\n", &k);
-    s = skip(s, he, "\r\n", &v);
-    if (k.len == tmp.len) continue;
-    while (v.len > 0 && v.ptr[v.len - 1] == ' ') v.len--;  // Trim spaces
-    if (k.len == 0) break;
-    // MG_INFO(("--HH [%.*s] [%.*s] [%.*s]", (int) tmp.len - 1, tmp.ptr,
-    //(int) k.len, k.ptr, (int) v.len, v.ptr));
-    h[i].name = k;
-    h[i].value = v;
-  }
+static bool ff_remove(const char *path) {
+  return f_unlink(path) == FR_OK;
 }
 
-int mg_http_parse(const char *s, size_t len, struct mg_http_message *hm) {
-  int is_response, req_len = mg_http_get_request_len((unsigned char *) s, len);
-  const char *end = s == NULL ? NULL : s + req_len, *qs;  // Cannot add to NULL
-  struct mg_str *cl;
+static bool ff_mkdir(const char *path) {
+  return f_mkdir(path) == FR_OK;
+}
 
-  memset(hm, 0, sizeof(*hm));
-  if (req_len <= 0) return req_len;
+struct mg_fs mg_fs_fat = {ff_stat,  ff_list, ff_open,   ff_close,  ff_read,
+                          ff_write, ff_seek, ff_rename, ff_remove, ff_mkdir};
+#endif
 
-  hm->message.ptr = hm->head.ptr = s;
-  hm->body.ptr = end;
-  hm->head.len = (size_t) req_len;
-  hm->chunk.ptr = end;
-  hm->message.len = hm->body.len = (size_t) ~0;  // Set body length to infinite
+#ifdef MG_ENABLE_LINES
+#line 1 "src/fs_packed.c"
+#endif
 
-  // Parse request line
-  s = skip(s, end, " ", &hm->method);
-  s = skip(s, end, " ", &hm->uri);
-  s = skip(s, end, "\r\n", &hm->proto);
 
-  // Sanity check. Allow protocol/reason to be empty
-  if (hm->method.len == 0 || hm->uri.len == 0) return -1;
 
-  // If URI contains '?' character, setup query string
-  if ((qs = (const char *) memchr(hm->uri.ptr, '?', hm->uri.len)) != NULL) {
-    hm->query.ptr = qs + 1;
-    hm->query.len = (size_t) (&hm->uri.ptr[hm->uri.len] - (qs + 1));
-    hm->uri.len = (size_t) (qs - hm->uri.ptr);
-  }
 
-  mg_http_parse_headers(s, end, hm->headers,
-                        sizeof(hm->headers) / sizeof(hm->headers[0]));
-  if ((cl = mg_http_get_header(hm, "Content-Length")) != NULL) {
-    hm->body.len = (size_t) mg_to64(*cl);
-    hm->message.len = (size_t) req_len + hm->body.len;
-  }
+struct packed_file {
+  const char *data;
+  size_t size;
+  size_t pos;
+};
 
-  // mg_http_parse() is used to parse both HTTP requests and HTTP
-  // responses. If HTTP response does not have Content-Length set, then
-  // body is read until socket is closed, i.e. body.len is infinite (~0).
-  //
-  // For HTTP requests though, according to
-  // http://tools.ietf.org/html/rfc7231#section-8.1.3,
-  // only POST and PUT methods have defined body semantics.
-  // Therefore, if Content-Length is not specified and methods are
-  // not one of PUT or POST, set body length to 0.
-  //
-  // So, if it is HTTP request, and Content-Length is not set,
-  // and method is not (PUT or POST) then reset body length to zero.
-  is_response = mg_ncasecmp(hm->method.ptr, "HTTP/", 5) == 0;
-  if (hm->body.len == (size_t) ~0 && !is_response &&
-      mg_vcasecmp(&hm->method, "PUT") != 0 &&
-      mg_vcasecmp(&hm->method, "POST") != 0) {
-    hm->body.len = 0;
-    hm->message.len = (size_t) req_len;
-  }
+#if MG_ENABLE_PACKED_FS
+#else
+const char *mg_unpack(const char *path, size_t *size, time_t *mtime) {
+  *size = 0, *mtime = 0;
+  (void) path;
+  return NULL;
+}
+const char *mg_unlist(size_t no) {
+  (void) no;
+  return NULL;
+}
+#endif
 
-  // The 204 (No content) responses also have 0 body length
-  if (hm->body.len == (size_t) ~0 && is_response &&
-      mg_vcasecmp(&hm->uri, "204") == 0) {
-    hm->body.len = 0;
-    hm->message.len = (size_t) req_len;
-  }
+struct mg_str mg_unpacked(const char *path) {
+  size_t len = 0;
+  const char *buf = mg_unpack(path, &len, NULL);
+  return mg_str_n(buf, len);
+}
 
-  return req_len;
+static int is_dir_prefix(const char *prefix, size_t n, const char *path) {
+  // MG_INFO(("[%.*s] [%s] %c", (int) n, prefix, path, path[n]));
+  return n < strlen(path) && strncmp(prefix, path, n) == 0 &&
+         (n == 0 || path[n] == '/' || path[n - 1] == '/');
 }
 
-static void mg_http_vprintf_chunk(struct mg_connection *c, const char *fmt,
-                                  va_list *ap) {
-  size_t len = c->send.len;
-  mg_send(c, "        \r\n", 10);
-  mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, ap);
-  if (c->send.len >= len + 10) {
-    mg_snprintf((char *) c->send.buf + len, 9, "%08lx", c->send.len - len - 10);
-    c->send.buf[len + 8] = '\r';
-    if (c->send.len == len + 10) c->is_resp = 0;  // Last chunk, reset marker
+static int packed_stat(const char *path, size_t *size, time_t *mtime) {
+  const char *p;
+  size_t i, n = strlen(path);
+  if (mg_unpack(path, size, mtime)) return MG_FS_READ;  // Regular file
+  // Scan all files. If `path` is a dir prefix for any of them, it's a dir
+  for (i = 0; (p = mg_unlist(i)) != NULL; i++) {
+    if (is_dir_prefix(path, n, p)) return MG_FS_DIR;
   }
-  mg_send(c, "\r\n", 2);
+  return 0;
 }
 
-void mg_http_printf_chunk(struct mg_connection *c, const char *fmt, ...) {
-  va_list ap;
-  va_start(ap, fmt);
-  mg_http_vprintf_chunk(c, fmt, &ap);
-  va_end(ap);
+static void packed_list(const char *dir, void (*fn)(const char *, void *),
+                        void *userdata) {
+  char buf[MG_PATH_MAX], tmp[sizeof(buf)];
+  const char *path, *begin, *end;
+  size_t i, n = strlen(dir);
+  tmp[0] = '\0';  // Previously listed entry
+  for (i = 0; (path = mg_unlist(i)) != NULL; i++) {
+    if (!is_dir_prefix(dir, n, path)) continue;
+    begin = &path[n + 1];
+    end = strchr(begin, '/');
+    if (end == NULL) end = begin + strlen(begin);
+    mg_snprintf(buf, sizeof(buf), "%.*s", (int) (end - begin), begin);
+    buf[sizeof(buf) - 1] = '\0';
+    // If this entry has been already listed, skip
+    // NOTE: we're assuming that file list is sorted alphabetically
+    if (strcmp(buf, tmp) == 0) continue;
+    fn(buf, userdata);  // Not yet listed, call user function
+    strcpy(tmp, buf);   // And save this entry as listed
+  }
 }
 
-void mg_http_write_chunk(struct mg_connection *c, const char *buf, size_t len) {
-  mg_printf(c, "%lx\r\n", (unsigned long) len);
-  mg_send(c, buf, len);
-  mg_send(c, "\r\n", 2);
-  if (len == 0) c->is_resp = 0;
+static void *packed_open(const char *path, int flags) {
+  size_t size = 0;
+  const char *data = mg_unpack(path, &size, NULL);
+  struct packed_file *fp = NULL;
+  if (data == NULL) return NULL;
+  if (flags & MG_FS_WRITE) return NULL;
+  if ((fp = (struct packed_file *) calloc(1, sizeof(*fp))) != NULL) {
+    fp->size = size;
+    fp->data = data;
+  }
+  return (void *) fp;
 }
 
-// clang-format off
-static const char *mg_http_status_code_str(int status_code) {
-  switch (status_code) {
-    case 100: return "Continue";
-    case 201: return "Created";
-    case 202: return "Accepted";
-    case 204: return "No Content";
-    case 206: return "Partial Content";
-    case 301: return "Moved Permanently";
-    case 302: return "Found";
-    case 304: return "Not Modified";
-    case 400: return "Bad Request";
-    case 401: return "Unauthorized";
-    case 403: return "Forbidden";
-    case 404: return "Not Found";
-    case 418: return "I'm a teapot";
-    case 500: return "Internal Server Error";
-    case 501: return "Not Implemented";
-    default: return "OK";
-  }
+static void packed_close(void *fp) {
+  if (fp != NULL) free(fp);
 }
-// clang-format on
 
-void mg_http_reply(struct mg_connection *c, int code, const char *headers,
-                   const char *fmt, ...) {
-  va_list ap;
-  size_t len;
-  mg_printf(c, "HTTP/1.1 %d %s\r\n%sContent-Length:           \r\n\r\n", code,
-            mg_http_status_code_str(code), headers == NULL ? "" : headers);
-  len = c->send.len;
-  va_start(ap, fmt);
-  mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, &ap);
-  va_end(ap);
-  if (c->send.len > 15) {
-    mg_snprintf((char *) &c->send.buf[len - 14], 11, "%010lu",
-                (unsigned long) (c->send.len - len));
-    c->is_resp = 0;
-    c->send.buf[len - 4] = '\r';  // Change ending 0 to space
-  }
-  c->is_resp = 0;
+static size_t packed_read(void *fd, void *buf, size_t len) {
+  struct packed_file *fp = (struct packed_file *) fd;
+  if (fp->pos + len > fp->size) len = fp->size - fp->pos;
+  memcpy(buf, &fp->data[fp->pos], len);
+  fp->pos += len;
+  return len;
 }
 
-static void http_cb(struct mg_connection *, int, void *, void *);
-static void restore_http_cb(struct mg_connection *c) {
-  mg_fs_close((struct mg_fd *) c->pfn_data);
-  c->pfn_data = NULL;
-  c->pfn = http_cb;
-  c->is_resp = 0;
+static size_t packed_write(void *fd, const void *buf, size_t len) {
+  (void) fd, (void) buf, (void) len;
+  return 0;
 }
 
-char *mg_http_etag(char *buf, size_t len, size_t size, time_t mtime);
-char *mg_http_etag(char *buf, size_t len, size_t size, time_t mtime) {
-  mg_snprintf(buf, len, "\"%lld.%lld\"", (int64_t) mtime, (int64_t) size);
-  return buf;
+static size_t packed_seek(void *fd, size_t offset) {
+  struct packed_file *fp = (struct packed_file *) fd;
+  fp->pos = offset;
+  if (fp->pos > fp->size) fp->pos = fp->size;
+  return fp->pos;
 }
 
-static void static_cb(struct mg_connection *c, int ev, void *ev_data,
-                      void *fn_data) {
-  if (ev == MG_EV_WRITE || ev == MG_EV_POLL) {
-    struct mg_fd *fd = (struct mg_fd *) fn_data;
-    // Read to send IO buffer directly, avoid extra on-stack buffer
-    size_t n, max = MG_IO_SIZE, space;
-    size_t *cl = (size_t *) &c->data[(sizeof(c->data) - sizeof(size_t)) /
-                                     sizeof(size_t) * sizeof(size_t)];
-    if (c->send.size < max) mg_iobuf_resize(&c->send, max);
-    if (c->send.len >= c->send.size) return;  // Rate limit
-    if ((space = c->send.size - c->send.len) > *cl) space = *cl;
-    n = fd->fs->rd(fd->fd, c->send.buf + c->send.len, space);
-    c->send.len += n;
-    *cl -= n;
-    if (n == 0) restore_http_cb(c);
-  } else if (ev == MG_EV_CLOSE) {
-    restore_http_cb(c);
-  }
-  (void) ev_data;
+static bool packed_rename(const char *from, const char *to) {
+  (void) from, (void) to;
+  return false;
 }
 
-// Known mime types. Keep it outside guess_content_type() function, since
-// some environments don't like it defined there.
-// clang-format off
-static struct mg_str s_known_types[] = {
-    MG_C_STR("html"), MG_C_STR("text/html; charset=utf-8"),
-    MG_C_STR("htm"), MG_C_STR("text/html; charset=utf-8"),
-    MG_C_STR("css"), MG_C_STR("text/css; charset=utf-8"),
-    MG_C_STR("js"), MG_C_STR("text/javascript; charset=utf-8"),
-    MG_C_STR("gif"), MG_C_STR("image/gif"),
-    MG_C_STR("png"), MG_C_STR("image/png"),
-    MG_C_STR("jpg"), MG_C_STR("image/jpeg"),
-    MG_C_STR("jpeg"), MG_C_STR("image/jpeg"),
-    MG_C_STR("woff"), MG_C_STR("font/woff"),
-    MG_C_STR("ttf"), MG_C_STR("font/ttf"),
-    MG_C_STR("svg"), MG_C_STR("image/svg+xml"),
-    MG_C_STR("txt"), MG_C_STR("text/plain; charset=utf-8"),
-    MG_C_STR("avi"), MG_C_STR("video/x-msvideo"),
-    MG_C_STR("csv"), MG_C_STR("text/csv"),
-    MG_C_STR("doc"), MG_C_STR("application/msword"),
-    MG_C_STR("exe"), MG_C_STR("application/octet-stream"),
-    MG_C_STR("gz"), MG_C_STR("application/gzip"),
-    MG_C_STR("ico"), MG_C_STR("image/x-icon"),
-    MG_C_STR("json"), MG_C_STR("application/json"),
-    MG_C_STR("mov"), MG_C_STR("video/quicktime"),
-    MG_C_STR("mp3"), MG_C_STR("audio/mpeg"),
-    MG_C_STR("mp4"), MG_C_STR("video/mp4"),
-    MG_C_STR("mpeg"), MG_C_STR("video/mpeg"),
-    MG_C_STR("pdf"), MG_C_STR("application/pdf"),
-    MG_C_STR("shtml"), MG_C_STR("text/html; charset=utf-8"),
-    MG_C_STR("tgz"), MG_C_STR("application/tar-gz"),
-    MG_C_STR("wav"), MG_C_STR("audio/wav"),
-    MG_C_STR("webp"), MG_C_STR("image/webp"),
-    MG_C_STR("zip"), MG_C_STR("application/zip"),
-    MG_C_STR("3gp"), MG_C_STR("video/3gpp"),
-    {0, 0},
-};
-// clang-format on
+static bool packed_remove(const char *path) {
+  (void) path;
+  return false;
+}
 
-static struct mg_str guess_content_type(struct mg_str path, const char *extra) {
-  struct mg_str k, v, s = mg_str(extra);
-  size_t i = 0;
+static bool packed_mkdir(const char *path) {
+  (void) path;
+  return false;
+}
 
-  // Shrink path to its extension only
-  while (i < path.len && path.ptr[path.len - i - 1] != '.') i++;
-  path.ptr += path.len - i;
-  path.len = i;
+struct mg_fs mg_fs_packed = {
+    packed_stat,  packed_list, packed_open,   packed_close,  packed_read,
+    packed_write, packed_seek, packed_rename, packed_remove, packed_mkdir};
 
-  // Process user-provided mime type overrides, if any
-  while (mg_commalist(&s, &k, &v)) {
-    if (mg_strcmp(path, k) == 0) return v;
-  }
+#ifdef MG_ENABLE_LINES
+#line 1 "src/fs_posix.c"
+#endif
 
-  // Process built-in mime types
-  for (i = 0; s_known_types[i].ptr != NULL; i += 2) {
-    if (mg_strcmp(path, s_known_types[i]) == 0) return s_known_types[i + 1];
-  }
 
-  return mg_str("text/plain; charset=utf-8");
-}
+#if MG_ENABLE_POSIX_FS
 
-static int getrange(struct mg_str *s, int64_t *a, int64_t *b) {
-  size_t i, numparsed = 0;
-  // MG_INFO(("%.*s", (int) s->len, s->ptr));
-  for (i = 0; i + 6 < s->len; i++) {
-    if (memcmp(&s->ptr[i], "bytes=", 6) == 0) {
-      struct mg_str p = mg_str_n(s->ptr + i + 6, s->len - i - 6);
-      if (p.len > 0 && p.ptr[0] >= '0' && p.ptr[0] <= '9') numparsed++;
-      *a = mg_to64(p);
-      // MG_INFO(("PPP [%.*s] %d", (int) p.len, p.ptr, numparsed));
-      while (p.len && p.ptr[0] >= '0' && p.ptr[0] <= '9') p.ptr++, p.len--;
-      if (p.len && p.ptr[0] == '-') p.ptr++, p.len--;
-      *b = mg_to64(p);
-      if (p.len > 0 && p.ptr[0] >= '0' && p.ptr[0] <= '9') numparsed++;
-      // MG_INFO(("PPP [%.*s] %d", (int) p.len, p.ptr, numparsed));
-      break;
-    }
-  }
-  return (int) numparsed;
-}
+#ifndef MG_STAT_STRUCT
+#define MG_STAT_STRUCT stat
+#endif
 
-void mg_http_serve_file(struct mg_connection *c, struct mg_http_message *hm,
-                        const char *path,
-                        const struct mg_http_serve_opts *opts) {
-  char etag[64], tmp[MG_PATH_MAX];
-  struct mg_fs *fs = opts->fs == NULL ? &mg_fs_posix : opts->fs;
-  struct mg_fd *fd = path == NULL ? NULL : mg_fs_open(fs, path, MG_FS_READ);
-  size_t size = 0;
-  time_t mtime = 0;
-  struct mg_str *inm = NULL;
-  struct mg_str mime = guess_content_type(mg_str(path), opts->mime_types);
-  bool gzip = false;
+#ifndef MG_STAT_FUNC
+#define MG_STAT_FUNC stat
+#endif
 
-  // If file does not exist, we try to open file PATH.gz - and if such
-  // pre-compressed .gz file exists, serve it with the Content-Encoding: gzip
-  // Note - we ignore Accept-Encoding, cause we don't have a choice
-  if (fd == NULL) {
-    MG_DEBUG(("NULL [%s]", path));
-    mg_snprintf(tmp, sizeof(tmp), "%s.gz", path);
-    if ((fd = mg_fs_open(fs, tmp, MG_FS_READ)) != NULL) {
-      gzip = true;
-      path = tmp;
-    } else if (opts->page404 != NULL) {
-      // No precompressed file, serve 404
-      fd = mg_fs_open(fs, opts->page404, MG_FS_READ);
-      mime = guess_content_type(mg_str(path), opts->mime_types);
-      path = opts->page404;
+static int p_stat(const char *path, size_t *size, time_t *mtime) {
+#if !defined(S_ISDIR)
+  MG_ERROR(("stat() API is not supported. %p %p %p", path, size, mtime));
+  return 0;
+#else
+#if MG_ARCH == MG_ARCH_WIN32
+  struct _stati64 st;
+  wchar_t tmp[MG_PATH_MAX];
+  MultiByteToWideChar(CP_UTF8, 0, path, -1, tmp, sizeof(tmp) / sizeof(tmp[0]));
+  if (_wstati64(tmp, &st) != 0) return 0;
+  // If path is a symlink, windows reports 0 in st.st_size.
+  // Get a real file size by opening it and jumping to the end
+  if (st.st_size == 0 && (st.st_mode & _S_IFREG)) {
+    FILE *fp = _wfopen(tmp, L"rb");
+    if (fp != NULL) {
+      fseek(fp, 0, SEEK_END);
+      if (ftell(fp) > 0) st.st_size = ftell(fp);  // Use _ftelli64 on win10+
+      fclose(fp);
     }
   }
+#else
+  struct MG_STAT_STRUCT st;
+  if (MG_STAT_FUNC(path, &st) != 0) return 0;
+#endif
+  if (size) *size = (size_t) st.st_size;
+  if (mtime) *mtime = st.st_mtime;
+  return MG_FS_READ | MG_FS_WRITE | (S_ISDIR(st.st_mode) ? MG_FS_DIR : 0);
+#endif
+}
 
-  if (fd == NULL || fs->st(path, &size, &mtime) == 0) {
-    mg_http_reply(c, 404, opts->extra_headers, "Not found\n");
-    mg_fs_close(fd);
-    // NOTE: mg_http_etag() call should go first!
-  } else if (mg_http_etag(etag, sizeof(etag), size, mtime) != NULL &&
-             (inm = mg_http_get_header(hm, "If-None-Match")) != NULL &&
-             mg_vcasecmp(inm, etag) == 0) {
-    mg_fs_close(fd);
-    mg_http_reply(c, 304, opts->extra_headers, "");
-  } else {
-    int n, status = 200;
-    char range[100];
-    int64_t r1 = 0, r2 = 0, cl = (int64_t) size;
+#if MG_ARCH == MG_ARCH_WIN32
+struct dirent {
+  char d_name[MAX_PATH];
+};
 
-    // Handle Range header
-    struct mg_str *rh = mg_http_get_header(hm, "Range");
-    range[0] = '\0';
-    if (rh != NULL && (n = getrange(rh, &r1, &r2)) > 0 && r1 >= 0 && r2 >= 0) {
-      // If range is specified like "400-", set second limit to content len
-      if (n == 1) r2 = cl - 1;
-      if (r1 > r2 || r2 >= cl) {
-        status = 416;
-        cl = 0;
-        mg_snprintf(range, sizeof(range), "Content-Range: bytes */%lld\r\n",
-                    (int64_t) size);
-      } else {
-        status = 206;
-        cl = r2 - r1 + 1;
-        mg_snprintf(range, sizeof(range),
-                    "Content-Range: bytes %lld-%lld/%lld\r\n", r1, r1 + cl - 1,
-                    (int64_t) size);
-        fs->sk(fd->fd, (size_t) r1);
-      }
-    }
-    mg_printf(c,
-              "HTTP/1.1 %d %s\r\n"
-              "Content-Type: %.*s\r\n"
-              "Etag: %s\r\n"
-              "Content-Length: %llu\r\n"
-              "%s%s%s\r\n",
-              status, mg_http_status_code_str(status), (int) mime.len, mime.ptr,
-              etag, cl, gzip ? "Content-Encoding: gzip\r\n" : "", range,
-              opts->extra_headers ? opts->extra_headers : "");
-    if (mg_vcasecmp(&hm->method, "HEAD") == 0) {
-      c->is_draining = 1;
-      c->is_resp = 0;
-      mg_fs_close(fd);
-    } else {
-      // Track to-be-sent content length at the end of c->data, aligned
-      size_t *clp = (size_t *) &c->data[(sizeof(c->data) - sizeof(size_t)) /
-                                        sizeof(size_t) * sizeof(size_t)];
-      c->pfn = static_cb;
-      c->pfn_data = fd;
-      *clp = (size_t) cl;
-    }
+typedef struct win32_dir {
+  HANDLE handle;
+  WIN32_FIND_DATAW info;
+  struct dirent result;
+} DIR;
+
+#if 0
+int gettimeofday(struct timeval *tv, void *tz) {
+  FILETIME ft;
+  unsigned __int64 tmpres = 0;
+
+  if (tv != NULL) {
+    GetSystemTimeAsFileTime(&ft);
+    tmpres |= ft.dwHighDateTime;
+    tmpres <<= 32;
+    tmpres |= ft.dwLowDateTime;
+    tmpres /= 10;  // convert into microseconds
+    tmpres -= (int64_t) 11644473600000000;
+    tv->tv_sec = (long) (tmpres / 1000000UL);
+    tv->tv_usec = (long) (tmpres % 1000000UL);
   }
+  (void) tz;
+  return 0;
 }
+#endif
 
-struct printdirentrydata {
-  struct mg_connection *c;
-  struct mg_http_message *hm;
-  const struct mg_http_serve_opts *opts;
-  const char *dir;
-};
+static int to_wchar(const char *path, wchar_t *wbuf, size_t wbuf_len) {
+  int ret;
+  char buf[MAX_PATH * 2], buf2[MAX_PATH * 2], *p;
+  strncpy(buf, path, sizeof(buf));
+  buf[sizeof(buf) - 1] = '\0';
+  // Trim trailing slashes. Leave backslash for paths like "X:\"
+  p = buf + strlen(buf) - 1;
+  while (p > buf && p[-1] != ':' && (p[0] == '\\' || p[0] == '/')) *p-- = '\0';
+  memset(wbuf, 0, wbuf_len * sizeof(wchar_t));
+  ret = MultiByteToWideChar(CP_UTF8, 0, buf, -1, wbuf, (int) wbuf_len);
+  // Convert back to Unicode. If doubly-converted string does not match the
+  // original, something is fishy, reject.
+  WideCharToMultiByte(CP_UTF8, 0, wbuf, (int) wbuf_len, buf2, sizeof(buf2),
+                      NULL, NULL);
+  if (strcmp(buf, buf2) != 0) {
+    wbuf[0] = L'\0';
+    ret = 0;
+  }
+  return ret;
+}
 
-static void printdirentry(const char *name, void *userdata) {
-  struct printdirentrydata *d = (struct printdirentrydata *) userdata;
-  struct mg_fs *fs = d->opts->fs == NULL ? &mg_fs_posix : d->opts->fs;
-  size_t size = 0;
-  time_t t = 0;
-  char path[MG_PATH_MAX], sz[40], mod[40];
-  int flags, n = 0;
+DIR *opendir(const char *name) {
+  DIR *d = NULL;
+  wchar_t wpath[MAX_PATH];
+  DWORD attrs;
 
-  // MG_DEBUG(("[%s] [%s]", d->dir, name));
-  if (mg_snprintf(path, sizeof(path), "%s%c%s", d->dir, '/', name) >
-      sizeof(path)) {
-    MG_ERROR(("%s truncated", name));
-  } else if ((flags = fs->st(path, &size, &t)) == 0) {
-    MG_ERROR(("%lu stat(%s): %d", d->c->id, path, errno));
+  if (name == NULL) {
+    SetLastError(ERROR_BAD_ARGUMENTS);
+  } else if ((d = (DIR *) calloc(1, sizeof(*d))) == NULL) {
+    SetLastError(ERROR_NOT_ENOUGH_MEMORY);
   } else {
-    const char *slash = flags & MG_FS_DIR ? "/" : "";
-    if (flags & MG_FS_DIR) {
-      mg_snprintf(sz, sizeof(sz), "%s", "[DIR]");
+    to_wchar(name, wpath, sizeof(wpath) / sizeof(wpath[0]));
+    attrs = GetFileAttributesW(wpath);
+    if (attrs != 0Xffffffff && (attrs & FILE_ATTRIBUTE_DIRECTORY)) {
+      (void) wcscat(wpath, L"\\*");
+      d->handle = FindFirstFileW(wpath, &d->info);
+      d->result.d_name[0] = '\0';
     } else {
-      mg_snprintf(sz, sizeof(sz), "%lld", (uint64_t) size);
+      free(d);
+      d = NULL;
     }
-#if defined(MG_HTTP_DIRLIST_TIME)
-    char time_str[30];
-    struct tm *time_info = localtime(&t);
-    strftime(time_str, sizeof time_str, "%Y/%m/%d %H:%M:%S", time_info);
-    mg_snprintf(mod, sizeof(mod), "%s", time_str);
-#elif defined(MG_HTTP_DIRLIST_TIME_UTC)
-    char time_str[30];
-    struct tm *time_info = gmtime(&t);
-    strftime(time_str, sizeof time_str, "%Y/%m/%d %H:%M:%S", time_info);
-    mg_snprintf(mod, sizeof(mod), "%s", time_str);
-#else
-    mg_snprintf(mod, sizeof(mod), "%ld", (unsigned long) t);
-#endif
-    n = (int) mg_url_encode(name, strlen(name), path, sizeof(path));
-    mg_printf(d->c,
-              "  <tr><td><a href=\"%.*s%s\">%s%s</a></td>"
-              "<td name=%lu>%s</td><td name=%lld>%s</td></tr>\n",
-              n, path, slash, name, slash, (unsigned long) t, mod,
-              flags & MG_FS_DIR ? (int64_t) -1 : (int64_t) size, sz);
   }
+  return d;
 }
 
-static void listdir(struct mg_connection *c, struct mg_http_message *hm,
-                    const struct mg_http_serve_opts *opts, char *dir) {
-  const char *sort_js_code =
-      "<script>function srt(tb, sc, so, d) {"
-      "var tr = Array.prototype.slice.call(tb.rows, 0),"
-      "tr = tr.sort(function (a, b) { var c1 = a.cells[sc], c2 = b.cells[sc],"
-      "n1 = c1.getAttribute('name'), n2 = c2.getAttribute('name'), "
-      "t1 = a.cells[2].getAttribute('name'), "
-      "t2 = b.cells[2].getAttribute('name'); "
-      "return so * (t1 < 0 && t2 >= 0 ? -1 : t2 < 0 && t1 >= 0 ? 1 : "
-      "n1 ? parseInt(n2) - parseInt(n1) : "
-      "c1.textContent.trim().localeCompare(c2.textContent.trim())); });";
-  const char *sort_js_code2 =
-      "for (var i = 0; i < tr.length; i++) tb.appendChild(tr[i]); "
-      "if (!d) window.location.hash = ('sc=' + sc + '&so=' + so); "
-      "};"
-      "window.onload = function() {"
-      "var tb = document.getElementById('tb');"
-      "var m = /sc=([012]).so=(1|-1)/.exec(window.location.hash) || [0, 2, 1];"
-      "var sc = m[1], so = m[2]; document.onclick = function(ev) { "
-      "var c = ev.target.rel; if (c) {if (c == sc) so *= -1; srt(tb, c, so); "
-      "sc = c; ev.preventDefault();}};"
-      "srt(tb, sc, so, true);"
-      "}"
-      "</script>";
-  struct mg_fs *fs = opts->fs == NULL ? &mg_fs_posix : opts->fs;
-  struct printdirentrydata d = {c, hm, opts, dir};
-  char tmp[10], buf[MG_PATH_MAX];
-  size_t off, n;
-  int len = mg_url_decode(hm->uri.ptr, hm->uri.len, buf, sizeof(buf), 0);
-  struct mg_str uri = len > 0 ? mg_str_n(buf, (size_t) len) : hm->uri;
-
-  mg_printf(c,
-            "HTTP/1.1 200 OK\r\n"
-            "Content-Type: text/html; charset=utf-8\r\n"
-            "%s"
-            "Content-Length:         \r\n\r\n",
-            opts->extra_headers == NULL ? "" : opts->extra_headers);
-  off = c->send.len;  // Start of body
-  mg_printf(c,
-            "<!DOCTYPE html><html><head><title>Index of %.*s</title>%s%s"
-            "<style>th,td {text-align: left; padding-right: 1em; "
-            "font-family: monospace; }</style></head>"
-            "<body><h1>Index of %.*s</h1><table cellpadding=\"0\"><thead>"
-            "<tr><th><a href=\"#\" rel=\"0\">Name</a></th><th>"
-            "<a href=\"#\" rel=\"1\">Modified</a></th>"
-            "<th><a href=\"#\" rel=\"2\">Size</a></th></tr>"
-            "<tr><td colspan=\"3\"><hr></td></tr>"
-            "</thead>"
-            "<tbody id=\"tb\">\n",
-            (int) uri.len, uri.ptr, sort_js_code, sort_js_code2, (int) uri.len,
-            uri.ptr);
-  mg_printf(c, "%s",
-            "  <tr><td><a href=\"..\">..</a></td>"
-            "<td name=-1></td><td name=-1>[DIR]</td></tr>\n");
-
-  fs->ls(dir, printdirentry, &d);
-  mg_printf(c,
-            "</tbody><tfoot><tr><td colspan=\"3\"><hr></td></tr></tfoot>"
-            "</table><address>Mongoose v.%s</address></body></html>\n",
-            MG_VERSION);
-  n = mg_snprintf(tmp, sizeof(tmp), "%lu", (unsigned long) (c->send.len - off));
-  if (n > sizeof(tmp)) n = 0;
-  memcpy(c->send.buf + off - 12, tmp, n);  // Set content length
-  c->is_resp = 0;                          // Mark response end
+int closedir(DIR *d) {
+  int result = 0;
+  if (d != NULL) {
+    if (d->handle != INVALID_HANDLE_VALUE)
+      result = FindClose(d->handle) ? 0 : -1;
+    free(d);
+  } else {
+    result = -1;
+    SetLastError(ERROR_BAD_ARGUMENTS);
+  }
+  return result;
 }
 
-// Resolve requested file into `path` and return its fs->st() result
-static int uri_to_path2(struct mg_connection *c, struct mg_http_message *hm,
-                        struct mg_fs *fs, struct mg_str url, struct mg_str dir,
-                        char *path, size_t path_size) {
-  int flags, tmp;
-  // Append URI to the root_dir, and sanitize it
-  size_t n = mg_snprintf(path, path_size, "%.*s", (int) dir.len, dir.ptr);
-  if (n > path_size) n = path_size;
-  path[path_size - 1] = '\0';
-  if (n + 2 < path_size) path[n++] = '/', path[n] = '\0';
-  mg_url_decode(hm->uri.ptr + url.len, hm->uri.len - url.len, path + n,
-                path_size - n, 0);
-  path[path_size - 1] = '\0';  // Double-check
-  mg_remove_double_dots(path);
-  n = strlen(path);
-  while (n > 1 && path[n - 1] == '/') path[--n] = 0;  // Trim trailing slashes
-  flags = mg_vcmp(&hm->uri, "/") == 0 ? MG_FS_DIR : fs->st(path, NULL, NULL);
-  MG_VERBOSE(("%lu %.*s -> %s %d", c->id, (int) hm->uri.len, hm->uri.ptr, path,
-              flags));
-  if (flags == 0) {
-    // Do nothing - let's caller decide
-  } else if ((flags & MG_FS_DIR) && hm->uri.len > 0 &&
-             hm->uri.ptr[hm->uri.len - 1] != '/') {
-    mg_printf(c,
-              "HTTP/1.1 301 Moved\r\n"
-              "Location: %.*s/\r\n"
-              "Content-Length: 0\r\n"
+struct dirent *readdir(DIR *d) {
+  struct dirent *result = NULL;
+  if (d != NULL) {
+    memset(&d->result, 0, sizeof(d->result));
+    if (d->handle != INVALID_HANDLE_VALUE) {
+      result = &d->result;
+      WideCharToMultiByte(CP_UTF8, 0, d->info.cFileName, -1, result->d_name,
+                          sizeof(result->d_name), NULL, NULL);
+      if (!FindNextFileW(d->handle, &d->info)) {
+        FindClose(d->handle);
+        d->handle = INVALID_HANDLE_VALUE;
+      }
+    } else {
+      SetLastError(ERROR_FILE_NOT_FOUND);
+    }
+  } else {
+    SetLastError(ERROR_BAD_ARGUMENTS);
+  }
+  return result;
+}
+#endif
+
+static void p_list(const char *dir, void (*fn)(const char *, void *),
+                   void *userdata) {
+#if MG_ENABLE_DIRLIST
+  struct dirent *dp;
+  DIR *dirp;
+  if ((dirp = (opendir(dir))) == NULL) return;
+  while ((dp = readdir(dirp)) != NULL) {
+    if (!strcmp(dp->d_name, ".") || !strcmp(dp->d_name, "..")) continue;
+    fn(dp->d_name, userdata);
+  }
+  closedir(dirp);
+#else
+  (void) dir, (void) fn, (void) userdata;
+#endif
+}
+
+static void *p_open(const char *path, int flags) {
+#if MG_ARCH == MG_ARCH_WIN32
+  const char *mode = flags == MG_FS_READ ? "rb" : "a+b";
+  wchar_t b1[MG_PATH_MAX], b2[10];
+  MultiByteToWideChar(CP_UTF8, 0, path, -1, b1, sizeof(b1) / sizeof(b1[0]));
+  MultiByteToWideChar(CP_UTF8, 0, mode, -1, b2, sizeof(b2) / sizeof(b2[0]));
+  return (void *) _wfopen(b1, b2);
+#else
+  const char *mode = flags == MG_FS_READ ? "rbe" : "a+be";  // e for CLOEXEC
+  return (void *) fopen(path, mode);
+#endif
+}
+
+static void p_close(void *fp) {
+  fclose((FILE *) fp);
+}
+
+static size_t p_read(void *fp, void *buf, size_t len) {
+  return fread(buf, 1, len, (FILE *) fp);
+}
+
+static size_t p_write(void *fp, const void *buf, size_t len) {
+  return fwrite(buf, 1, len, (FILE *) fp);
+}
+
+static size_t p_seek(void *fp, size_t offset) {
+#if (defined(_FILE_OFFSET_BITS) && _FILE_OFFSET_BITS == 64) ||  \
+    (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L) || \
+    (defined(_XOPEN_SOURCE) && _XOPEN_SOURCE >= 600)
+  if (fseeko((FILE *) fp, (off_t) offset, SEEK_SET) != 0) (void) 0;
+#else
+  if (fseek((FILE *) fp, (long) offset, SEEK_SET) != 0) (void) 0;
+#endif
+  return (size_t) ftell((FILE *) fp);
+}
+
+static bool p_rename(const char *from, const char *to) {
+  return rename(from, to) == 0;
+}
+
+static bool p_remove(const char *path) {
+  return remove(path) == 0;
+}
+
+static bool p_mkdir(const char *path) {
+  return mkdir(path, 0775) == 0;
+}
+
+#else
+
+static int p_stat(const char *path, size_t *size, time_t *mtime) {
+  (void) path, (void) size, (void) mtime;
+  return 0;
+}
+static void p_list(const char *path, void (*fn)(const char *, void *),
+                   void *userdata) {
+  (void) path, (void) fn, (void) userdata;
+}
+static void *p_open(const char *path, int flags) {
+  (void) path, (void) flags;
+  return NULL;
+}
+static void p_close(void *fp) {
+  (void) fp;
+}
+static size_t p_read(void *fd, void *buf, size_t len) {
+  (void) fd, (void) buf, (void) len;
+  return 0;
+}
+static size_t p_write(void *fd, const void *buf, size_t len) {
+  (void) fd, (void) buf, (void) len;
+  return 0;
+}
+static size_t p_seek(void *fd, size_t offset) {
+  (void) fd, (void) offset;
+  return (size_t) ~0;
+}
+static bool p_rename(const char *from, const char *to) {
+  (void) from, (void) to;
+  return false;
+}
+static bool p_remove(const char *path) {
+  (void) path;
+  return false;
+}
+static bool p_mkdir(const char *path) {
+  (void) path;
+  return false;
+}
+#endif
+
+struct mg_fs mg_fs_posix = {p_stat,  p_list, p_open,   p_close,  p_read,
+                            p_write, p_seek, p_rename, p_remove, p_mkdir};
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/http.c"
+#endif
+
+
+
+
+
+
+
+
+
+
+
+
+
+static int mg_ncasecmp(const char *s1, const char *s2, size_t len) {
+  int diff = 0;
+  if (len > 0) do {
+      int c = *s1++, d = *s2++;
+      if (c >= 'A' && c <= 'Z') c += 'a' - 'A';
+      if (d >= 'A' && d <= 'Z') d += 'a' - 'A';
+      diff = c - d;
+    } while (diff == 0 && s1[-1] != '\0' && --len > 0);
+  return diff;
+}
+
+bool mg_to_size_t(struct mg_str str, size_t *val);
+bool mg_to_size_t(struct mg_str str, size_t *val) {
+  size_t i = 0, max = (size_t) -1, max2 = max / 10, result = 0, ndigits = 0;
+  while (i < str.len && (str.buf[i] == ' ' || str.buf[i] == '\t')) i++;
+  if (i < str.len && str.buf[i] == '-') return false;
+  while (i < str.len && str.buf[i] >= '0' && str.buf[i] <= '9') {
+    size_t digit = (size_t) (str.buf[i] - '0');
+    if (result > max2) return false;  // Overflow
+    result *= 10;
+    if (result > max - digit) return false;  // Overflow
+    result += digit;
+    i++, ndigits++;
+  }
+  while (i < str.len && (str.buf[i] == ' ' || str.buf[i] == '\t')) i++;
+  if (ndigits == 0) return false;  // #2322: Content-Length = 1 * DIGIT
+  if (i != str.len) return false;  // Ditto
+  *val = (size_t) result;
+  return true;
+}
+
+// Chunk deletion marker is the MSB in the "processed" counter
+#define MG_DMARK ((size_t) 1 << (sizeof(size_t) * 8 - 1))
+
+// Multipart POST example:
+// --xyz
+// Content-Disposition: form-data; name="val"
+//
+// abcdef
+// --xyz
+// Content-Disposition: form-data; name="foo"; filename="a.txt"
+// Content-Type: text/plain
+//
+// hello world
+//
+// --xyz--
+size_t mg_http_next_multipart(struct mg_str body, size_t ofs,
+                              struct mg_http_part *part) {
+  struct mg_str cd = mg_str_n("Content-Disposition", 19);
+  const char *s = body.buf;
+  size_t b = ofs, h1, h2, b1, b2, max = body.len;
+
+  // Init part params
+  if (part != NULL) part->name = part->filename = part->body = mg_str_n(0, 0);
+
+  // Skip boundary
+  while (b + 2 < max && s[b] != '\r' && s[b + 1] != '\n') b++;
+  if (b <= ofs || b + 2 >= max) return 0;
+  // MG_INFO(("B: %zu %zu [%.*s]", ofs, b - ofs, (int) (b - ofs), s));
+
+  // Skip headers
+  h1 = h2 = b + 2;
+  for (;;) {
+    while (h2 + 2 < max && s[h2] != '\r' && s[h2 + 1] != '\n') h2++;
+    if (h2 == h1) break;
+    if (h2 + 2 >= max) return 0;
+    // MG_INFO(("Header: [%.*s]", (int) (h2 - h1), &s[h1]));
+    if (part != NULL && h1 + cd.len + 2 < h2 && s[h1 + cd.len] == ':' &&
+        mg_ncasecmp(&s[h1], cd.buf, cd.len) == 0) {
+      struct mg_str v = mg_str_n(&s[h1 + cd.len + 2], h2 - (h1 + cd.len + 2));
+      part->name = mg_http_get_header_var(v, mg_str_n("name", 4));
+      part->filename = mg_http_get_header_var(v, mg_str_n("filename", 8));
+    }
+    h1 = h2 = h2 + 2;
+  }
+  b1 = b2 = h2 + 2;
+  while (b2 + 2 + (b - ofs) + 2 < max && !(s[b2] == '\r' && s[b2 + 1] == '\n' &&
+                                           memcmp(&s[b2 + 2], s, b - ofs) == 0))
+    b2++;
+
+  if (b2 + 2 >= max) return 0;
+  if (part != NULL) part->body = mg_str_n(&s[b1], b2 - b1);
+  // MG_INFO(("Body: [%.*s]", (int) (b2 - b1), &s[b1]));
+  return b2 + 2;
+}
+
+void mg_http_bauth(struct mg_connection *c, const char *user,
+                   const char *pass) {
+  struct mg_str u = mg_str(user), p = mg_str(pass);
+  size_t need = c->send.len + 36 + (u.len + p.len) * 2;
+  if (c->send.size < need) mg_iobuf_resize(&c->send, need);
+  if (c->send.size >= need) {
+    size_t i, n = 0;
+    char *buf = (char *) &c->send.buf[c->send.len];
+    memcpy(buf, "Authorization: Basic ", 21);  // DON'T use mg_send!
+    for (i = 0; i < u.len; i++) {
+      n = mg_base64_update(((unsigned char *) u.buf)[i], buf + 21, n);
+    }
+    if (p.len > 0) {
+      n = mg_base64_update(':', buf + 21, n);
+      for (i = 0; i < p.len; i++) {
+        n = mg_base64_update(((unsigned char *) p.buf)[i], buf + 21, n);
+      }
+    }
+    n = mg_base64_final(buf + 21, n);
+    c->send.len += 21 + (size_t) n + 2;
+    memcpy(&c->send.buf[c->send.len - 2], "\r\n", 2);
+  } else {
+    MG_ERROR(("%lu oom %d->%d ", c->id, (int) c->send.size, (int) need));
+  }
+}
+
+struct mg_str mg_http_var(struct mg_str buf, struct mg_str name) {
+  struct mg_str entry, k, v, result = mg_str_n(NULL, 0);
+  while (mg_span(buf, &entry, &buf, '&')) {
+    if (mg_span(entry, &k, &v, '=') && name.len == k.len &&
+        mg_ncasecmp(name.buf, k.buf, k.len) == 0) {
+      result = v;
+      break;
+    }
+  }
+  return result;
+}
+
+int mg_http_get_var(const struct mg_str *buf, const char *name, char *dst,
+                    size_t dst_len) {
+  int len;
+  if (dst != NULL && dst_len > 0) {
+    dst[0] = '\0';  // If destination buffer is valid, always nul-terminate it
+  }
+  if (dst == NULL || dst_len == 0) {
+    len = -2;  // Bad destination
+  } else if (buf->buf == NULL || name == NULL || buf->len == 0) {
+    len = -1;  // Bad source
+  } else {
+    struct mg_str v = mg_http_var(*buf, mg_str(name));
+    if (v.buf == NULL) {
+      len = -4;  // Name does not exist
+    } else {
+      len = mg_url_decode(v.buf, v.len, dst, dst_len, 1);
+      if (len < 0) len = -3;  // Failed to decode
+    }
+  }
+  return len;
+}
+
+static bool isx(int c) {
+  return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') ||
+         (c >= 'A' && c <= 'F');
+}
+
+int mg_url_decode(const char *src, size_t src_len, char *dst, size_t dst_len,
+                  int is_form_url_encoded) {
+  size_t i, j;
+  for (i = j = 0; i < src_len && j + 1 < dst_len; i++, j++) {
+    if (src[i] == '%') {
+      // Use `i + 2 < src_len`, not `i < src_len - 2`, note small src_len
+      if (i + 2 < src_len && isx(src[i + 1]) && isx(src[i + 2])) {
+        mg_str_to_num(mg_str_n(src + i + 1, 2), 16, &dst[j], sizeof(uint8_t));
+        i += 2;
+      } else {
+        return -1;
+      }
+    } else if (is_form_url_encoded && src[i] == '+') {
+      dst[j] = ' ';
+    } else {
+      dst[j] = src[i];
+    }
+  }
+  if (j < dst_len) dst[j] = '\0';  // Null-terminate the destination
+  return i >= src_len && j < dst_len ? (int) j : -1;
+}
+
+static bool isok(uint8_t c) {
+  return c == '\n' || c == '\r' || c >= ' ';
+}
+
+int mg_http_get_request_len(const unsigned char *buf, size_t buf_len) {
+  size_t i;
+  for (i = 0; i < buf_len; i++) {
+    if (!isok(buf[i])) return -1;
+    if ((i > 0 && buf[i] == '\n' && buf[i - 1] == '\n') ||
+        (i > 3 && buf[i] == '\n' && buf[i - 1] == '\r' && buf[i - 2] == '\n'))
+      return (int) i + 1;
+  }
+  return 0;
+}
+struct mg_str *mg_http_get_header(struct mg_http_message *h, const char *name) {
+  size_t i, n = strlen(name), max = sizeof(h->headers) / sizeof(h->headers[0]);
+  for (i = 0; i < max && h->headers[i].name.len > 0; i++) {
+    struct mg_str *k = &h->headers[i].name, *v = &h->headers[i].value;
+    if (n == k->len && mg_ncasecmp(k->buf, name, n) == 0) return v;
+  }
+  return NULL;
+}
+
+// Is it a valid utf-8 continuation byte
+static bool vcb(uint8_t c) {
+  return (c & 0xc0) == 0x80;
+}
+
+// Get character length (valid utf-8). Used to parse method, URI, headers
+static size_t clen(const char *s, const char *end) {
+  const unsigned char *u = (unsigned char *) s, c = *u;
+  long n = (long) (end - s);
+  if (c > ' ' && c < '~') return 1;  // Usual ascii printed char
+  if ((c & 0xe0) == 0xc0 && n > 1 && vcb(u[1])) return 2;  // 2-byte UTF8
+  if ((c & 0xf0) == 0xe0 && n > 2 && vcb(u[1]) && vcb(u[2])) return 3;
+  if ((c & 0xf8) == 0xf0 && n > 3 && vcb(u[1]) && vcb(u[2]) && vcb(u[3]))
+    return 4;
+  return 0;
+}
+
+// Skip until the newline. Return advanced `s`, or NULL on error
+static const char *skiptorn(const char *s, const char *end, struct mg_str *v) {
+  v->buf = (char *) s;
+  while (s < end && s[0] != '\n' && s[0] != '\r') s++, v->len++;  // To newline
+  if (s >= end || (s[0] == '\r' && s[1] != '\n')) return NULL;    // Stray \r
+  if (s < end && s[0] == '\r') s++;                               // Skip \r
+  if (s >= end || *s++ != '\n') return NULL;                      // Skip \n
+  return s;
+}
+
+static bool mg_http_parse_headers(const char *s, const char *end,
+                                  struct mg_http_header *h, size_t max_hdrs) {
+  size_t i, n;
+  for (i = 0; i < max_hdrs; i++) {
+    struct mg_str k = {NULL, 0}, v = {NULL, 0};
+    if (s >= end) return false;
+    if (s[0] == '\n' || (s[0] == '\r' && s[1] == '\n')) break;
+    k.buf = (char *) s;
+    while (s < end && s[0] != ':' && (n = clen(s, end)) > 0) s += n, k.len += n;
+    if (k.len == 0) return false;                     // Empty name
+    if (s >= end || clen(s, end) == 0) return false;  // Invalid UTF-8
+    if (*s++ != ':') return false;  // Invalid, not followed by :
+    // if (clen(s, end) == 0) return false;        // Invalid UTF-8
+    while (s < end && s[0] == ' ') s++;  // Skip spaces
+    if ((s = skiptorn(s, end, &v)) == NULL) return false;
+    while (v.len > 0 && v.buf[v.len - 1] == ' ') v.len--;  // Trim spaces
+    // MG_INFO(("--HH [%.*s] [%.*s]", (int) k.len, k.buf, (int) v.len, v.buf));
+    h[i].name = k, h[i].value = v;  // Success. Assign values
+  }
+  return true;
+}
+
+int mg_http_parse(const char *s, size_t len, struct mg_http_message *hm) {
+  int is_response, req_len = mg_http_get_request_len((unsigned char *) s, len);
+  const char *end = s == NULL ? NULL : s + req_len, *qs;  // Cannot add to NULL
+  const struct mg_str *cl;
+  size_t n;
+
+  memset(hm, 0, sizeof(*hm));
+  if (req_len <= 0) return req_len;
+
+  hm->message.buf = hm->head.buf = (char *) s;
+  hm->body.buf = (char *) end;
+  hm->head.len = (size_t) req_len;
+  hm->message.len = hm->body.len = (size_t) -1;  // Set body length to infinite
+
+  // Parse request line
+  hm->method.buf = (char *) s;
+  while (s < end && (n = clen(s, end)) > 0) s += n, hm->method.len += n;
+  while (s < end && s[0] == ' ') s++;  // Skip spaces
+  hm->uri.buf = (char *) s;
+  while (s < end && (n = clen(s, end)) > 0) s += n, hm->uri.len += n;
+  while (s < end && s[0] == ' ') s++;  // Skip spaces
+  if ((s = skiptorn(s, end, &hm->proto)) == NULL) return false;
+
+  // If URI contains '?' character, setup query string
+  if ((qs = (const char *) memchr(hm->uri.buf, '?', hm->uri.len)) != NULL) {
+    hm->query.buf = (char *) qs + 1;
+    hm->query.len = (size_t) (&hm->uri.buf[hm->uri.len] - (qs + 1));
+    hm->uri.len = (size_t) (qs - hm->uri.buf);
+  }
+
+  // Sanity check. Allow protocol/reason to be empty
+  // Do this check after hm->method.len and hm->uri.len are finalised
+  if (hm->method.len == 0 || hm->uri.len == 0) return -1;
+
+  if (!mg_http_parse_headers(s, end, hm->headers,
+                             sizeof(hm->headers) / sizeof(hm->headers[0])))
+    return -1;  // error when parsing
+  if ((cl = mg_http_get_header(hm, "Content-Length")) != NULL) {
+    if (mg_to_size_t(*cl, &hm->body.len) == false) return -1;
+    hm->message.len = (size_t) req_len + hm->body.len;
+  }
+
+  // mg_http_parse() is used to parse both HTTP requests and HTTP
+  // responses. If HTTP response does not have Content-Length set, then
+  // body is read until socket is closed, i.e. body.len is infinite (~0).
+  //
+  // For HTTP requests though, according to
+  // http://tools.ietf.org/html/rfc7231#section-8.1.3,
+  // only POST and PUT methods have defined body semantics.
+  // Therefore, if Content-Length is not specified and methods are
+  // not one of PUT or POST, set body length to 0.
+  //
+  // So, if it is HTTP request, and Content-Length is not set,
+  // and method is not (PUT or POST) then reset body length to zero.
+  is_response = mg_ncasecmp(hm->method.buf, "HTTP/", 5) == 0;
+  if (hm->body.len == (size_t) ~0 && !is_response &&
+      mg_strcasecmp(hm->method, mg_str("PUT")) != 0 &&
+      mg_strcasecmp(hm->method, mg_str("POST")) != 0) {
+    hm->body.len = 0;
+    hm->message.len = (size_t) req_len;
+  }
+
+  // The 204 (No content) responses also have 0 body length
+  if (hm->body.len == (size_t) ~0 && is_response &&
+      mg_strcasecmp(hm->uri, mg_str("204")) == 0) {
+    hm->body.len = 0;
+    hm->message.len = (size_t) req_len;
+  }
+  if (hm->message.len < (size_t) req_len) return -1;  // Overflow protection
+
+  return req_len;
+}
+
+static void mg_http_vprintf_chunk(struct mg_connection *c, const char *fmt,
+                                  va_list *ap) {
+  size_t len = c->send.len;
+  mg_send(c, "        \r\n", 10);
+  mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, ap);
+  if (c->send.len >= len + 10) {
+    mg_snprintf((char *) c->send.buf + len, 9, "%08lx", c->send.len - len - 10);
+    c->send.buf[len + 8] = '\r';
+    if (c->send.len == len + 10) c->is_resp = 0;  // Last chunk, reset marker
+  }
+  mg_send(c, "\r\n", 2);
+}
+
+void mg_http_printf_chunk(struct mg_connection *c, const char *fmt, ...) {
+  va_list ap;
+  va_start(ap, fmt);
+  mg_http_vprintf_chunk(c, fmt, &ap);
+  va_end(ap);
+}
+
+void mg_http_write_chunk(struct mg_connection *c, const char *buf, size_t len) {
+  mg_printf(c, "%lx\r\n", (unsigned long) len);
+  mg_send(c, buf, len);
+  mg_send(c, "\r\n", 2);
+  if (len == 0) c->is_resp = 0;
+}
+
+// clang-format off
+static const char *mg_http_status_code_str(int status_code) {
+  switch (status_code) {
+    case 100: return "Continue";
+    case 101: return "Switching Protocols";
+    case 102: return "Processing";
+    case 200: return "OK";
+    case 201: return "Created";
+    case 202: return "Accepted";
+    case 203: return "Non-authoritative Information";
+    case 204: return "No Content";
+    case 205: return "Reset Content";
+    case 206: return "Partial Content";
+    case 207: return "Multi-Status";
+    case 208: return "Already Reported";
+    case 226: return "IM Used";
+    case 300: return "Multiple Choices";
+    case 301: return "Moved Permanently";
+    case 302: return "Found";
+    case 303: return "See Other";
+    case 304: return "Not Modified";
+    case 305: return "Use Proxy";
+    case 307: return "Temporary Redirect";
+    case 308: return "Permanent Redirect";
+    case 400: return "Bad Request";
+    case 401: return "Unauthorized";
+    case 402: return "Payment Required";
+    case 403: return "Forbidden";
+    case 404: return "Not Found";
+    case 405: return "Method Not Allowed";
+    case 406: return "Not Acceptable";
+    case 407: return "Proxy Authentication Required";
+    case 408: return "Request Timeout";
+    case 409: return "Conflict";
+    case 410: return "Gone";
+    case 411: return "Length Required";
+    case 412: return "Precondition Failed";
+    case 413: return "Payload Too Large";
+    case 414: return "Request-URI Too Long";
+    case 415: return "Unsupported Media Type";
+    case 416: return "Requested Range Not Satisfiable";
+    case 417: return "Expectation Failed";
+    case 418: return "I'm a teapot";
+    case 421: return "Misdirected Request";
+    case 422: return "Unprocessable Entity";
+    case 423: return "Locked";
+    case 424: return "Failed Dependency";
+    case 426: return "Upgrade Required";
+    case 428: return "Precondition Required";
+    case 429: return "Too Many Requests";
+    case 431: return "Request Header Fields Too Large";
+    case 444: return "Connection Closed Without Response";
+    case 451: return "Unavailable For Legal Reasons";
+    case 499: return "Client Closed Request";
+    case 500: return "Internal Server Error";
+    case 501: return "Not Implemented";
+    case 502: return "Bad Gateway";
+    case 503: return "Service Unavailable";
+    case 504: return "Gateway Timeout";
+    case 505: return "HTTP Version Not Supported";
+    case 506: return "Variant Also Negotiates";
+    case 507: return "Insufficient Storage";
+    case 508: return "Loop Detected";
+    case 510: return "Not Extended";
+    case 511: return "Network Authentication Required";
+    case 599: return "Network Connect Timeout Error";
+    default: return "";
+  }
+}
+// clang-format on
+
+void mg_http_reply(struct mg_connection *c, int code, const char *headers,
+                   const char *fmt, ...) {
+  va_list ap;
+  size_t len;
+  mg_printf(c, "HTTP/1.1 %d %s\r\n%sContent-Length:            \r\n\r\n", code,
+            mg_http_status_code_str(code), headers == NULL ? "" : headers);
+  len = c->send.len;
+  va_start(ap, fmt);
+  mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, &ap);
+  va_end(ap);
+  if (c->send.len > 16) {
+    size_t n = mg_snprintf((char *) &c->send.buf[len - 15], 11, "%-10lu",
+                           (unsigned long) (c->send.len - len));
+    c->send.buf[len - 15 + n] = ' ';  // Change ending 0 to space
+  }
+  c->is_resp = 0;
+}
+
+static void http_cb(struct mg_connection *, int, void *);
+static void restore_http_cb(struct mg_connection *c) {
+  mg_fs_close((struct mg_fd *) c->pfn_data);
+  c->pfn_data = NULL;
+  c->pfn = http_cb;
+  c->is_resp = 0;
+}
+
+char *mg_http_etag(char *buf, size_t len, size_t size, time_t mtime);
+char *mg_http_etag(char *buf, size_t len, size_t size, time_t mtime) {
+  mg_snprintf(buf, len, "\"%lld.%lld\"", (int64_t) mtime, (int64_t) size);
+  return buf;
+}
+
+static void static_cb(struct mg_connection *c, int ev, void *ev_data) {
+  if (ev == MG_EV_WRITE || ev == MG_EV_POLL) {
+    struct mg_fd *fd = (struct mg_fd *) c->pfn_data;
+    // Read to send IO buffer directly, avoid extra on-stack buffer
+    size_t n, max = MG_IO_SIZE, space;
+    size_t *cl = (size_t *) &c->data[(sizeof(c->data) - sizeof(size_t)) /
+                                     sizeof(size_t) * sizeof(size_t)];
+    if (c->send.size < max) mg_iobuf_resize(&c->send, max);
+    if (c->send.len >= c->send.size) return;  // Rate limit
+    if ((space = c->send.size - c->send.len) > *cl) space = *cl;
+    n = fd->fs->rd(fd->fd, c->send.buf + c->send.len, space);
+    c->send.len += n;
+    *cl -= n;
+    if (n == 0) restore_http_cb(c);
+  } else if (ev == MG_EV_CLOSE) {
+    restore_http_cb(c);
+  }
+  (void) ev_data;
+}
+
+// Known mime types. Keep it outside guess_content_type() function, since
+// some environments don't like it defined there.
+// clang-format off
+#define MG_C_STR(a) { (char *) (a), sizeof(a) - 1 }
+static struct mg_str s_known_types[] = {
+    MG_C_STR("html"), MG_C_STR("text/html; charset=utf-8"),
+    MG_C_STR("htm"), MG_C_STR("text/html; charset=utf-8"),
+    MG_C_STR("css"), MG_C_STR("text/css; charset=utf-8"),
+    MG_C_STR("js"), MG_C_STR("text/javascript; charset=utf-8"),
+    MG_C_STR("gif"), MG_C_STR("image/gif"),
+    MG_C_STR("png"), MG_C_STR("image/png"),
+    MG_C_STR("jpg"), MG_C_STR("image/jpeg"),
+    MG_C_STR("jpeg"), MG_C_STR("image/jpeg"),
+    MG_C_STR("woff"), MG_C_STR("font/woff"),
+    MG_C_STR("ttf"), MG_C_STR("font/ttf"),
+    MG_C_STR("svg"), MG_C_STR("image/svg+xml"),
+    MG_C_STR("txt"), MG_C_STR("text/plain; charset=utf-8"),
+    MG_C_STR("avi"), MG_C_STR("video/x-msvideo"),
+    MG_C_STR("csv"), MG_C_STR("text/csv"),
+    MG_C_STR("doc"), MG_C_STR("application/msword"),
+    MG_C_STR("exe"), MG_C_STR("application/octet-stream"),
+    MG_C_STR("gz"), MG_C_STR("application/gzip"),
+    MG_C_STR("ico"), MG_C_STR("image/x-icon"),
+    MG_C_STR("json"), MG_C_STR("application/json"),
+    MG_C_STR("mov"), MG_C_STR("video/quicktime"),
+    MG_C_STR("mp3"), MG_C_STR("audio/mpeg"),
+    MG_C_STR("mp4"), MG_C_STR("video/mp4"),
+    MG_C_STR("mpeg"), MG_C_STR("video/mpeg"),
+    MG_C_STR("pdf"), MG_C_STR("application/pdf"),
+    MG_C_STR("shtml"), MG_C_STR("text/html; charset=utf-8"),
+    MG_C_STR("tgz"), MG_C_STR("application/tar-gz"),
+    MG_C_STR("wav"), MG_C_STR("audio/wav"),
+    MG_C_STR("webp"), MG_C_STR("image/webp"),
+    MG_C_STR("zip"), MG_C_STR("application/zip"),
+    MG_C_STR("3gp"), MG_C_STR("video/3gpp"),
+    {0, 0},
+};
+// clang-format on
+
+static struct mg_str guess_content_type(struct mg_str path, const char *extra) {
+  struct mg_str entry, k, v, s = mg_str(extra);
+  size_t i = 0;
+
+  // Shrink path to its extension only
+  while (i < path.len && path.buf[path.len - i - 1] != '.') i++;
+  path.buf += path.len - i;
+  path.len = i;
+
+  // Process user-provided mime type overrides, if any
+  while (mg_span(s, &entry, &s, ',')) {
+    if (mg_span(entry, &k, &v, '=') && mg_strcmp(path, k) == 0) return v;
+  }
+
+  // Process built-in mime types
+  for (i = 0; s_known_types[i].buf != NULL; i += 2) {
+    if (mg_strcmp(path, s_known_types[i]) == 0) return s_known_types[i + 1];
+  }
+
+  return mg_str("text/plain; charset=utf-8");
+}
+
+static int getrange(struct mg_str *s, size_t *a, size_t *b) {
+  size_t i, numparsed = 0;
+  for (i = 0; i + 6 < s->len; i++) {
+    struct mg_str k, v = mg_str_n(s->buf + i + 6, s->len - i - 6);
+    if (memcmp(&s->buf[i], "bytes=", 6) != 0) continue;
+    if (mg_span(v, &k, &v, '-')) {
+      if (mg_to_size_t(k, a)) numparsed++;
+      if (v.len > 0 && mg_to_size_t(v, b)) numparsed++;
+    } else {
+      if (mg_to_size_t(v, a)) numparsed++;
+    }
+    break;
+  }
+  return (int) numparsed;
+}
+
+void mg_http_serve_file(struct mg_connection *c, struct mg_http_message *hm,
+                        const char *path,
+                        const struct mg_http_serve_opts *opts) {
+  char etag[64], tmp[MG_PATH_MAX];
+  struct mg_fs *fs = opts->fs == NULL ? &mg_fs_posix : opts->fs;
+  struct mg_fd *fd = NULL;
+  size_t size = 0;
+  time_t mtime = 0;
+  struct mg_str *inm = NULL;
+  struct mg_str mime = guess_content_type(mg_str(path), opts->mime_types);
+  bool gzip = false;
+
+  if (path != NULL) {
+    // If a browser sends us "Accept-Encoding: gzip", try to open .gz first
+    struct mg_str *ae = mg_http_get_header(hm, "Accept-Encoding");
+    if (ae != NULL) {
+      char *ae_ = mg_mprintf("%.*s", ae->len, ae->buf);
+      if (ae_ != NULL && strstr(ae_, "gzip") != NULL) {
+        mg_snprintf(tmp, sizeof(tmp), "%s.gz", path);
+        fd = mg_fs_open(fs, tmp, MG_FS_READ);
+        if (fd != NULL) gzip = true, path = tmp;
+      }
+      free(ae_);
+    }
+    // No luck opening .gz? Open what we've told to open
+    if (fd == NULL) fd = mg_fs_open(fs, path, MG_FS_READ);
+  }
+
+  // Failed to open, and page404 is configured? Open it, then
+  if (fd == NULL && opts->page404 != NULL) {
+    fd = mg_fs_open(fs, opts->page404, MG_FS_READ);
+    path = opts->page404;
+    mime = guess_content_type(mg_str(path), opts->mime_types);
+  }
+
+  if (fd == NULL || fs->st(path, &size, &mtime) == 0) {
+    mg_http_reply(c, 404, opts->extra_headers, "Not found\n");
+    mg_fs_close(fd);
+    // NOTE: mg_http_etag() call should go first!
+  } else if (mg_http_etag(etag, sizeof(etag), size, mtime) != NULL &&
+             (inm = mg_http_get_header(hm, "If-None-Match")) != NULL &&
+             mg_strcasecmp(*inm, mg_str(etag)) == 0) {
+    mg_fs_close(fd);
+    mg_http_reply(c, 304, opts->extra_headers, "");
+  } else {
+    int n, status = 200;
+    char range[100];
+    size_t r1 = 0, r2 = 0, cl = size;
+
+    // Handle Range header
+    struct mg_str *rh = mg_http_get_header(hm, "Range");
+    range[0] = '\0';
+    if (rh != NULL && (n = getrange(rh, &r1, &r2)) > 0) {
+      // If range is specified like "400-", set second limit to content len
+      if (n == 1) r2 = cl - 1;
+      if (r1 > r2 || r2 >= cl) {
+        status = 416;
+        cl = 0;
+        mg_snprintf(range, sizeof(range), "Content-Range: bytes */%lld\r\n",
+                    (int64_t) size);
+      } else {
+        status = 206;
+        cl = r2 - r1 + 1;
+        mg_snprintf(range, sizeof(range),
+                    "Content-Range: bytes %llu-%llu/%llu\r\n", (uint64_t) r1,
+                    (uint64_t) (r1 + cl - 1), (uint64_t) size);
+        fs->sk(fd->fd, r1);
+      }
+    }
+    mg_printf(c,
+              "HTTP/1.1 %d %s\r\n"
+              "Content-Type: %.*s\r\n"
+              "Etag: %s\r\n"
+              "Content-Length: %llu\r\n"
+              "%s%s%s\r\n",
+              status, mg_http_status_code_str(status), (int) mime.len, mime.buf,
+              etag, (uint64_t) cl, gzip ? "Content-Encoding: gzip\r\n" : "",
+              range, opts->extra_headers ? opts->extra_headers : "");
+    if (mg_strcasecmp(hm->method, mg_str("HEAD")) == 0) {
+      c->is_draining = 1;
+      c->is_resp = 0;
+      mg_fs_close(fd);
+    } else {
+      // Track to-be-sent content length at the end of c->data, aligned
+      size_t *clp = (size_t *) &c->data[(sizeof(c->data) - sizeof(size_t)) /
+                                        sizeof(size_t) * sizeof(size_t)];
+      c->pfn = static_cb;
+      c->pfn_data = fd;
+      *clp = cl;
+    }
+  }
+}
+
+struct printdirentrydata {
+  struct mg_connection *c;
+  struct mg_http_message *hm;
+  const struct mg_http_serve_opts *opts;
+  const char *dir;
+};
+
+#if MG_ENABLE_DIRLIST
+static void printdirentry(const char *name, void *userdata) {
+  struct printdirentrydata *d = (struct printdirentrydata *) userdata;
+  struct mg_fs *fs = d->opts->fs == NULL ? &mg_fs_posix : d->opts->fs;
+  size_t size = 0;
+  time_t t = 0;
+  char path[MG_PATH_MAX], sz[40], mod[40];
+  int flags, n = 0;
+
+  // MG_DEBUG(("[%s] [%s]", d->dir, name));
+  if (mg_snprintf(path, sizeof(path), "%s%c%s", d->dir, '/', name) >
+      sizeof(path)) {
+    MG_ERROR(("%s truncated", name));
+  } else if ((flags = fs->st(path, &size, &t)) == 0) {
+    MG_ERROR(("%lu stat(%s): %d", d->c->id, path, errno));
+  } else {
+    const char *slash = flags & MG_FS_DIR ? "/" : "";
+    if (flags & MG_FS_DIR) {
+      mg_snprintf(sz, sizeof(sz), "%s", "[DIR]");
+    } else {
+      mg_snprintf(sz, sizeof(sz), "%lld", (uint64_t) size);
+    }
+#if defined(MG_HTTP_DIRLIST_TIME_FMT)
+    {
+      char time_str[40];
+      struct tm *time_info = localtime(&t);
+      strftime(time_str, sizeof time_str, "%Y/%m/%d %H:%M:%S", time_info);
+      mg_snprintf(mod, sizeof(mod), "%s", time_str);
+    }
+#else
+    mg_snprintf(mod, sizeof(mod), "%lu", (unsigned long) t);
+#endif
+    n = (int) mg_url_encode(name, strlen(name), path, sizeof(path));
+    mg_printf(d->c,
+              "  <tr><td><a href=\"%.*s%s\">%s%s</a></td>"
+              "<td name=%lu>%s</td><td name=%lld>%s</td></tr>\n",
+              n, path, slash, name, slash, (unsigned long) t, mod,
+              flags & MG_FS_DIR ? (int64_t) -1 : (int64_t) size, sz);
+  }
+}
+
+static void listdir(struct mg_connection *c, struct mg_http_message *hm,
+                    const struct mg_http_serve_opts *opts, char *dir) {
+  const char *sort_js_code =
+      "<script>function srt(tb, sc, so, d) {"
+      "var tr = Array.prototype.slice.call(tb.rows, 0),"
+      "tr = tr.sort(function (a, b) { var c1 = a.cells[sc], c2 = b.cells[sc],"
+      "n1 = c1.getAttribute('name'), n2 = c2.getAttribute('name'), "
+      "t1 = a.cells[2].getAttribute('name'), "
+      "t2 = b.cells[2].getAttribute('name'); "
+      "return so * (t1 < 0 && t2 >= 0 ? -1 : t2 < 0 && t1 >= 0 ? 1 : "
+      "n1 ? parseInt(n2) - parseInt(n1) : "
+      "c1.textContent.trim().localeCompare(c2.textContent.trim())); });";
+  const char *sort_js_code2 =
+      "for (var i = 0; i < tr.length; i++) tb.appendChild(tr[i]); "
+      "if (!d) window.location.hash = ('sc=' + sc + '&so=' + so); "
+      "};"
+      "window.onload = function() {"
+      "var tb = document.getElementById('tb');"
+      "var m = /sc=([012]).so=(1|-1)/.exec(window.location.hash) || [0, 2, 1];"
+      "var sc = m[1], so = m[2]; document.onclick = function(ev) { "
+      "var c = ev.target.rel; if (c) {if (c == sc) so *= -1; srt(tb, c, so); "
+      "sc = c; ev.preventDefault();}};"
+      "srt(tb, sc, so, true);"
+      "}"
+      "</script>";
+  struct mg_fs *fs = opts->fs == NULL ? &mg_fs_posix : opts->fs;
+  struct printdirentrydata d = {c, hm, opts, dir};
+  char tmp[10], buf[MG_PATH_MAX];
+  size_t off, n;
+  int len = mg_url_decode(hm->uri.buf, hm->uri.len, buf, sizeof(buf), 0);
+  struct mg_str uri = len > 0 ? mg_str_n(buf, (size_t) len) : hm->uri;
+
+  mg_printf(c,
+            "HTTP/1.1 200 OK\r\n"
+            "Content-Type: text/html; charset=utf-8\r\n"
+            "%s"
+            "Content-Length:         \r\n\r\n",
+            opts->extra_headers == NULL ? "" : opts->extra_headers);
+  off = c->send.len;  // Start of body
+  mg_printf(c,
+            "<!DOCTYPE html><html><head><title>Index of %.*s</title>%s%s"
+            "<style>th,td {text-align: left; padding-right: 1em; "
+            "font-family: monospace; }</style></head>"
+            "<body><h1>Index of %.*s</h1><table cellpadding=\"0\"><thead>"
+            "<tr><th><a href=\"#\" rel=\"0\">Name</a></th><th>"
+            "<a href=\"#\" rel=\"1\">Modified</a></th>"
+            "<th><a href=\"#\" rel=\"2\">Size</a></th></tr>"
+            "<tr><td colspan=\"3\"><hr></td></tr>"
+            "</thead>"
+            "<tbody id=\"tb\">\n",
+            (int) uri.len, uri.buf, sort_js_code, sort_js_code2, (int) uri.len,
+            uri.buf);
+  mg_printf(c, "%s",
+            "  <tr><td><a href=\"..\">..</a></td>"
+            "<td name=-1></td><td name=-1>[DIR]</td></tr>\n");
+
+  fs->ls(dir, printdirentry, &d);
+  mg_printf(c,
+            "</tbody><tfoot><tr><td colspan=\"3\"><hr></td></tr></tfoot>"
+            "</table><address>Mongoose v.%s</address></body></html>\n",
+            MG_VERSION);
+  n = mg_snprintf(tmp, sizeof(tmp), "%lu", (unsigned long) (c->send.len - off));
+  if (n > sizeof(tmp)) n = 0;
+  memcpy(c->send.buf + off - 12, tmp, n);  // Set content length
+  c->is_resp = 0;                          // Mark response end
+}
+#endif
+
+// Resolve requested file into `path` and return its fs->st() result
+static int uri_to_path2(struct mg_connection *c, struct mg_http_message *hm,
+                        struct mg_fs *fs, struct mg_str url, struct mg_str dir,
+                        char *path, size_t path_size) {
+  int flags, tmp;
+  // Append URI to the root_dir, and sanitize it
+  size_t n = mg_snprintf(path, path_size, "%.*s", (int) dir.len, dir.buf);
+  if (n + 2 >= path_size) {
+    mg_http_reply(c, 400, "", "Exceeded path size");
+    return -1;
+  }
+  path[path_size - 1] = '\0';
+  // Terminate root dir with slash
+  if (n > 0 && path[n - 1] != '/') path[n++] = '/', path[n] = '\0';
+  if (url.len < hm->uri.len) {
+    mg_url_decode(hm->uri.buf + url.len, hm->uri.len - url.len, path + n,
+                  path_size - n, 0);
+  }
+  path[path_size - 1] = '\0';  // Double-check
+  if (!mg_path_is_sane(mg_str_n(path, path_size))) {
+    mg_http_reply(c, 400, "", "Invalid path");
+    return -1;
+  }
+  n = strlen(path);
+  while (n > 1 && path[n - 1] == '/') path[--n] = 0;  // Trim trailing slashes
+  flags = mg_strcmp(hm->uri, mg_str("/")) == 0 ? MG_FS_DIR
+                                               : fs->st(path, NULL, NULL);
+  MG_VERBOSE(("%lu %.*s -> %s %d", c->id, (int) hm->uri.len, hm->uri.buf, path,
+              flags));
+  if (flags == 0) {
+    // Do nothing - let's caller decide
+  } else if ((flags & MG_FS_DIR) && hm->uri.len > 0 &&
+             hm->uri.buf[hm->uri.len - 1] != '/') {
+    mg_printf(c,
+              "HTTP/1.1 301 Moved\r\n"
+              "Location: %.*s/\r\n"
+              "Content-Length: 0\r\n"
               "\r\n",
-              (int) hm->uri.len, hm->uri.ptr);
+              (int) hm->uri.len, hm->uri.buf);
     c->is_resp = 0;
     flags = -1;
   } else if (flags & MG_FS_DIR) {
@@ -2057,3318 +3036,11754 @@ static int uri_to_path2(struct mg_connection *c, struct mg_http_message *hm,
       path[n + 1 + strlen(MG_HTTP_INDEX)] =
           '\0';  // Remove appended .gz in index file name
     } else {
-      path[n] = '\0';  // Remove appended index file name
+      path[n] = '\0';  // Remove appended index file name
+    }
+  }
+  return flags;
+}
+
+static int uri_to_path(struct mg_connection *c, struct mg_http_message *hm,
+                       const struct mg_http_serve_opts *opts, char *path,
+                       size_t path_size) {
+  struct mg_fs *fs = opts->fs == NULL ? &mg_fs_posix : opts->fs;
+  struct mg_str k, v, part, s = mg_str(opts->root_dir), u = {NULL, 0}, p = u;
+  while (mg_span(s, &part, &s, ',')) {
+    if (!mg_span(part, &k, &v, '=')) k = part, v = mg_str_n(NULL, 0);
+    if (v.len == 0) v = k, k = mg_str("/"), u = k, p = v;
+    if (hm->uri.len < k.len) continue;
+    if (mg_strcmp(k, mg_str_n(hm->uri.buf, k.len)) != 0) continue;
+    u = k, p = v;
+  }
+  return uri_to_path2(c, hm, fs, u, p, path, path_size);
+}
+
+void mg_http_serve_dir(struct mg_connection *c, struct mg_http_message *hm,
+                       const struct mg_http_serve_opts *opts) {
+  char path[MG_PATH_MAX];
+  const char *sp = opts->ssi_pattern;
+  int flags = uri_to_path(c, hm, opts, path, sizeof(path));
+  if (flags < 0) {
+    // Do nothing: the response has already been sent by uri_to_path()
+  } else if (flags & MG_FS_DIR) {
+#if MG_ENABLE_DIRLIST
+    listdir(c, hm, opts, path);
+#else
+    mg_http_reply(c, 403, "", "Forbidden\n");
+#endif
+  } else if (flags && sp != NULL && mg_match(mg_str(path), mg_str(sp), NULL)) {
+    mg_http_serve_ssi(c, opts->root_dir, path);
+  } else {
+    mg_http_serve_file(c, hm, path, opts);
+  }
+}
+
+static bool mg_is_url_safe(int c) {
+  return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'z') ||
+         (c >= 'A' && c <= 'Z') || c == '.' || c == '_' || c == '-' || c == '~';
+}
+
+size_t mg_url_encode(const char *s, size_t sl, char *buf, size_t len) {
+  size_t i, n = 0;
+  for (i = 0; i < sl; i++) {
+    int c = *(unsigned char *) &s[i];
+    if (n + 4 >= len) return 0;
+    if (mg_is_url_safe(c)) {
+      buf[n++] = s[i];
+    } else {
+      mg_snprintf(&buf[n], 4, "%%%M", mg_print_hex, 1, &s[i]);
+      n += 3;
+    }
+  }
+  if (len > 0 && n < len - 1) buf[n] = '\0';  // Null-terminate the destination
+  if (len > 0) buf[len - 1] = '\0';           // Always.
+  return n;
+}
+
+void mg_http_creds(struct mg_http_message *hm, char *user, size_t userlen,
+                   char *pass, size_t passlen) {
+  struct mg_str *v = mg_http_get_header(hm, "Authorization");
+  user[0] = pass[0] = '\0';
+  if (v != NULL && v->len > 6 && memcmp(v->buf, "Basic ", 6) == 0) {
+    char buf[256];
+    size_t n = mg_base64_decode(v->buf + 6, v->len - 6, buf, sizeof(buf));
+    const char *p = (const char *) memchr(buf, ':', n > 0 ? n : 0);
+    if (p != NULL) {
+      mg_snprintf(user, userlen, "%.*s", p - buf, buf);
+      mg_snprintf(pass, passlen, "%.*s", n - (size_t) (p - buf) - 1, p + 1);
+    }
+  } else if (v != NULL && v->len > 7 && memcmp(v->buf, "Bearer ", 7) == 0) {
+    mg_snprintf(pass, passlen, "%.*s", (int) v->len - 7, v->buf + 7);
+  } else if ((v = mg_http_get_header(hm, "Cookie")) != NULL) {
+    struct mg_str t = mg_http_get_header_var(*v, mg_str_n("access_token", 12));
+    if (t.len > 0) mg_snprintf(pass, passlen, "%.*s", (int) t.len, t.buf);
+  } else {
+    mg_http_get_var(&hm->query, "access_token", pass, passlen);
+  }
+}
+
+static struct mg_str stripquotes(struct mg_str s) {
+  return s.len > 1 && s.buf[0] == '"' && s.buf[s.len - 1] == '"'
+             ? mg_str_n(s.buf + 1, s.len - 2)
+             : s;
+}
+
+struct mg_str mg_http_get_header_var(struct mg_str s, struct mg_str v) {
+  size_t i;
+  for (i = 0; v.len > 0 && i + v.len + 2 < s.len; i++) {
+    if (s.buf[i + v.len] == '=' && memcmp(&s.buf[i], v.buf, v.len) == 0) {
+      const char *p = &s.buf[i + v.len + 1], *b = p, *x = &s.buf[s.len];
+      int q = p < x && *p == '"' ? 1 : 0;
+      while (p < x &&
+             (q ? p == b || *p != '"' : *p != ';' && *p != ' ' && *p != ','))
+        p++;
+      // MG_INFO(("[%.*s] [%.*s] [%.*s]", (int) s.len, s.buf, (int) v.len,
+      // v.buf, (int) (p - b), b));
+      return stripquotes(mg_str_n(b, (size_t) (p - b + q)));
+    }
+  }
+  return mg_str_n(NULL, 0);
+}
+
+long mg_http_upload(struct mg_connection *c, struct mg_http_message *hm,
+                    struct mg_fs *fs, const char *dir, size_t max_size) {
+  char buf[20] = "0", file[MG_PATH_MAX], path[MG_PATH_MAX];
+  long res = 0, offset;
+  mg_http_get_var(&hm->query, "offset", buf, sizeof(buf));
+  mg_http_get_var(&hm->query, "file", file, sizeof(file));
+  offset = strtol(buf, NULL, 0);
+  mg_snprintf(path, sizeof(path), "%s%c%s", dir, MG_DIRSEP, file);
+  if (hm->body.len == 0) {
+    mg_http_reply(c, 200, "", "%ld", res);  // Nothing to write
+  } else if (file[0] == '\0') {
+    mg_http_reply(c, 400, "", "file required");
+    res = -1;
+  } else if (mg_path_is_sane(mg_str(file)) == false) {
+    mg_http_reply(c, 400, "", "%s: invalid file", file);
+    res = -2;
+  } else if (offset < 0) {
+    mg_http_reply(c, 400, "", "offset required");
+    res = -3;
+  } else if ((size_t) offset + hm->body.len > max_size) {
+    mg_http_reply(c, 400, "", "%s: over max size of %lu", path,
+                  (unsigned long) max_size);
+    res = -4;
+  } else {
+    struct mg_fd *fd;
+    size_t current_size = 0;
+    MG_DEBUG(("%s -> %lu bytes @ %ld", path, hm->body.len, offset));
+    if (offset == 0) fs->rm(path);  // If offset if 0, truncate file
+    fs->st(path, &current_size, NULL);
+    if (offset > 0 && current_size != (size_t) offset) {
+      mg_http_reply(c, 400, "", "%s: offset mismatch", path);
+      res = -5;
+    } else if ((fd = mg_fs_open(fs, path, MG_FS_WRITE)) == NULL) {
+      mg_http_reply(c, 400, "", "open(%s): %d", path, errno);
+      res = -6;
+    } else {
+      res = offset + (long) fs->wr(fd->fd, hm->body.buf, hm->body.len);
+      mg_fs_close(fd);
+      mg_http_reply(c, 200, "", "%ld", res);
+    }
+  }
+  return res;
+}
+
+int mg_http_status(const struct mg_http_message *hm) {
+  return atoi(hm->uri.buf);
+}
+
+static bool is_hex_digit(int c) {
+  return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') ||
+         (c >= 'A' && c <= 'F');
+}
+
+static int skip_chunk(const char *buf, int len, int *pl, int *dl) {
+  int i = 0, n = 0;
+  if (len < 3) return 0;
+  while (i < len && is_hex_digit(buf[i])) i++;
+  if (i == 0) return -1;                     // Error, no length specified
+  if (i > (int) sizeof(int) * 2) return -1;  // Chunk length is too big
+  if (len < i + 1 || buf[i] != '\r' || buf[i + 1] != '\n') return -1;  // Error
+  if (mg_str_to_num(mg_str_n(buf, (size_t) i), 16, &n, sizeof(int)) == false)
+    return -1;                    // Decode chunk length, overflow
+  if (n < 0) return -1;           // Error. TODO(): some checks now redundant
+  if (n > len - i - 4) return 0;  // Chunk not yet fully buffered
+  if (buf[i + n + 2] != '\r' || buf[i + n + 3] != '\n') return -1;  // Error
+  *pl = i + 2, *dl = n;
+  return i + 2 + n + 2;
+}
+
+static void http_cb(struct mg_connection *c, int ev, void *ev_data) {
+  if (ev == MG_EV_READ || ev == MG_EV_CLOSE) {
+    struct mg_http_message hm;
+    size_t ofs = 0;  // Parsing offset
+    while (c->is_resp == 0 && ofs < c->recv.len) {
+      const char *buf = (char *) c->recv.buf + ofs;
+      int n = mg_http_parse(buf, c->recv.len - ofs, &hm);
+      struct mg_str *te;  // Transfer - encoding header
+      bool is_chunked = false;
+      if (n < 0) {
+        // We don't use mg_error() here, to avoid closing pipelined requests
+        // prematurely, see #2592
+        MG_ERROR(("HTTP parse, %lu bytes", c->recv.len));
+        c->is_draining = 1;
+        mg_hexdump(buf, c->recv.len - ofs > 16 ? 16 : c->recv.len - ofs);
+        c->recv.len = 0;
+        return;
+      }
+      if (n == 0) break;                 // Request is not buffered yet
+      mg_call(c, MG_EV_HTTP_HDRS, &hm);  // Got all HTTP headers
+      if (ev == MG_EV_CLOSE) {           // If client did not set Content-Length
+        hm.message.len = c->recv.len - ofs;  // and closes now, deliver MSG
+        hm.body.len = hm.message.len - (size_t) (hm.body.buf - hm.message.buf);
+      }
+      if ((te = mg_http_get_header(&hm, "Transfer-Encoding")) != NULL) {
+        if (mg_strcasecmp(*te, mg_str("chunked")) == 0) {
+          is_chunked = true;
+        } else {
+          mg_error(c, "Invalid Transfer-Encoding");  // See #2460
+          return;
+        }
+      } else if (mg_http_get_header(&hm, "Content-length") == NULL) {
+        // #2593: HTTP packets must contain either Transfer-Encoding or
+        // Content-length
+        bool is_response = mg_ncasecmp(hm.method.buf, "HTTP/", 5) == 0;
+        bool require_content_len = false;
+        if (!is_response && (mg_strcasecmp(hm.method, mg_str("POST")) == 0 ||
+                             mg_strcasecmp(hm.method, mg_str("PUT")) == 0)) {
+          // POST and PUT should include an entity body. Therefore, they should
+          // contain a Content-length header. Other requests can also contain a
+          // body, but their content has no defined semantics (RFC 7231)
+          require_content_len = true;
+        } else if (is_response) {
+          // HTTP spec 7.2 Entity body: All other responses must include a body
+          // or Content-Length header field defined with a value of 0.
+          int status = mg_http_status(&hm);
+          require_content_len = status >= 200 && status != 204 && status != 304;
+        }
+        if (require_content_len) {
+          mg_http_reply(c, 411, "", "");
+          MG_ERROR(("%s", "Content length missing from request"));
+        }
+      }
+
+      if (is_chunked) {
+        // For chunked data, strip off prefixes and suffixes from chunks
+        // and relocate them right after the headers, then report a message
+        char *s = (char *) c->recv.buf + ofs + n;
+        int o = 0, pl, dl, cl, len = (int) (c->recv.len - ofs - (size_t) n);
+
+        // Find zero-length chunk (the end of the body)
+        while ((cl = skip_chunk(s + o, len - o, &pl, &dl)) > 0 && dl) o += cl;
+        if (cl == 0) break;  // No zero-len chunk, buffer more data
+        if (cl < 0) {
+          mg_error(c, "Invalid chunk");
+          break;
+        }
+
+        // Zero chunk found. Second pass: strip + relocate
+        o = 0, hm.body.len = 0, hm.message.len = (size_t) n;
+        while ((cl = skip_chunk(s + o, len - o, &pl, &dl)) > 0) {
+          memmove(s + hm.body.len, s + o + pl, (size_t) dl);
+          o += cl, hm.body.len += (size_t) dl, hm.message.len += (size_t) dl;
+          if (dl == 0) break;
+        }
+        ofs += (size_t) (n + o);
+      } else {  // Normal, non-chunked data
+        size_t len = c->recv.len - ofs - (size_t) n;
+        if (hm.body.len > len) break;  // Buffer more data
+        ofs += (size_t) n + hm.body.len;
+      }
+
+      if (c->is_accepted) c->is_resp = 1;  // Start generating response
+      mg_call(c, MG_EV_HTTP_MSG, &hm);     // User handler can clear is_resp
+    }
+    if (ofs > 0) mg_iobuf_del(&c->recv, 0, ofs);  // Delete processed data
+  }
+  (void) ev_data;
+}
+
+static void mg_hfn(struct mg_connection *c, int ev, void *ev_data) {
+  if (ev == MG_EV_HTTP_MSG) {
+    struct mg_http_message *hm = (struct mg_http_message *) ev_data;
+    if (mg_match(hm->uri, mg_str("/quit"), NULL)) {
+      mg_http_reply(c, 200, "", "ok\n");
+      c->is_draining = 1;
+      c->data[0] = 'X';
+    } else if (mg_match(hm->uri, mg_str("/debug"), NULL)) {
+      int level = (int) mg_json_get_long(hm->body, "$.level", MG_LL_DEBUG);
+      mg_log_set(level);
+      mg_http_reply(c, 200, "", "Debug level set to %d\n", level);
+    } else {
+      mg_http_reply(c, 200, "", "hi\n");
+    }
+  } else if (ev == MG_EV_CLOSE) {
+    if (c->data[0] == 'X') *(bool *) c->fn_data = true;
+  }
+}
+
+void mg_hello(const char *url) {
+  struct mg_mgr mgr;
+  bool done = false;
+  mg_mgr_init(&mgr);
+  if (mg_http_listen(&mgr, url, mg_hfn, &done) == NULL) done = true;
+  while (done == false) mg_mgr_poll(&mgr, 100);
+  mg_mgr_free(&mgr);
+}
+
+struct mg_connection *mg_http_connect(struct mg_mgr *mgr, const char *url,
+                                      mg_event_handler_t fn, void *fn_data) {
+  struct mg_connection *c = mg_connect(mgr, url, fn, fn_data);
+  if (c != NULL) c->pfn = http_cb;
+  return c;
+}
+
+struct mg_connection *mg_http_listen(struct mg_mgr *mgr, const char *url,
+                                     mg_event_handler_t fn, void *fn_data) {
+  struct mg_connection *c = mg_listen(mgr, url, fn, fn_data);
+  if (c != NULL) c->pfn = http_cb;
+  return c;
+}
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/iobuf.c"
+#endif
+
+
+
+
+
+static size_t roundup(size_t size, size_t align) {
+  return align == 0 ? size : (size + align - 1) / align * align;
+}
+
+int mg_iobuf_resize(struct mg_iobuf *io, size_t new_size) {
+  int ok = 1;
+  new_size = roundup(new_size, io->align);
+  if (new_size == 0) {
+    mg_bzero(io->buf, io->size);
+    free(io->buf);
+    io->buf = NULL;
+    io->len = io->size = 0;
+  } else if (new_size != io->size) {
+    // NOTE(lsm): do not use realloc here. Use calloc/free only, to ease the
+    // porting to some obscure platforms like FreeRTOS
+    void *p = calloc(1, new_size);
+    if (p != NULL) {
+      size_t len = new_size < io->len ? new_size : io->len;
+      if (len > 0 && io->buf != NULL) memmove(p, io->buf, len);
+      mg_bzero(io->buf, io->size);
+      free(io->buf);
+      io->buf = (unsigned char *) p;
+      io->size = new_size;
+    } else {
+      ok = 0;
+      MG_ERROR(("%lld->%lld", (uint64_t) io->size, (uint64_t) new_size));
+    }
+  }
+  return ok;
+}
+
+int mg_iobuf_init(struct mg_iobuf *io, size_t size, size_t align) {
+  io->buf = NULL;
+  io->align = align;
+  io->size = io->len = 0;
+  return mg_iobuf_resize(io, size);
+}
+
+size_t mg_iobuf_add(struct mg_iobuf *io, size_t ofs, const void *buf,
+                    size_t len) {
+  size_t new_size = roundup(io->len + len, io->align);
+  mg_iobuf_resize(io, new_size);      // Attempt to resize
+  if (new_size != io->size) len = 0;  // Resize failure, append nothing
+  if (ofs < io->len) memmove(io->buf + ofs + len, io->buf + ofs, io->len - ofs);
+  if (buf != NULL) memmove(io->buf + ofs, buf, len);
+  if (ofs > io->len) io->len += ofs - io->len;
+  io->len += len;
+  return len;
+}
+
+size_t mg_iobuf_del(struct mg_iobuf *io, size_t ofs, size_t len) {
+  if (ofs > io->len) ofs = io->len;
+  if (ofs + len > io->len) len = io->len - ofs;
+  if (io->buf) memmove(io->buf + ofs, io->buf + ofs + len, io->len - ofs - len);
+  if (io->buf) mg_bzero(io->buf + io->len - len, len);
+  io->len -= len;
+  return len;
+}
+
+void mg_iobuf_free(struct mg_iobuf *io) {
+  mg_iobuf_resize(io, 0);
+}
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/json.c"
+#endif
+
+
+
+
+static const char *escapeseq(int esc) {
+  return esc ? "\b\f\n\r\t\\\"" : "bfnrt\\\"";
+}
+
+static char json_esc(int c, int esc) {
+  const char *p, *esc1 = escapeseq(esc), *esc2 = escapeseq(!esc);
+  for (p = esc1; *p != '\0'; p++) {
+    if (*p == c) return esc2[p - esc1];
+  }
+  return 0;
+}
+
+static int mg_pass_string(const char *s, int len) {
+  int i;
+  for (i = 0; i < len; i++) {
+    if (s[i] == '\\' && i + 1 < len && json_esc(s[i + 1], 1)) {
+      i++;
+    } else if (s[i] == '\0') {
+      return MG_JSON_INVALID;
+    } else if (s[i] == '"') {
+      return i;
+    }
+  }
+  return MG_JSON_INVALID;
+}
+
+static double mg_atod(const char *p, int len, int *numlen) {
+  double d = 0.0;
+  int i = 0, sign = 1;
+
+  // Sign
+  if (i < len && *p == '-') {
+    sign = -1, i++;
+  } else if (i < len && *p == '+') {
+    i++;
+  }
+
+  // Decimal
+  for (; i < len && p[i] >= '0' && p[i] <= '9'; i++) {
+    d *= 10.0;
+    d += p[i] - '0';
+  }
+  d *= sign;
+
+  // Fractional
+  if (i < len && p[i] == '.') {
+    double frac = 0.0, base = 0.1;
+    i++;
+    for (; i < len && p[i] >= '0' && p[i] <= '9'; i++) {
+      frac += base * (p[i] - '0');
+      base /= 10.0;
+    }
+    d += frac * sign;
+  }
+
+  // Exponential
+  if (i < len && (p[i] == 'e' || p[i] == 'E')) {
+    int j, exp = 0, minus = 0;
+    i++;
+    if (i < len && p[i] == '-') minus = 1, i++;
+    if (i < len && p[i] == '+') i++;
+    while (i < len && p[i] >= '0' && p[i] <= '9' && exp < 308)
+      exp = exp * 10 + (p[i++] - '0');
+    if (minus) exp = -exp;
+    for (j = 0; j < exp; j++) d *= 10.0;
+    for (j = 0; j < -exp; j++) d /= 10.0;
+  }
+
+  if (numlen != NULL) *numlen = i;
+  return d;
+}
+
+// Iterate over object or array elements
+size_t mg_json_next(struct mg_str obj, size_t ofs, struct mg_str *key,
+                    struct mg_str *val) {
+  if (ofs >= obj.len) {
+    ofs = 0;  // Out of boundaries, stop scanning
+  } else if (obj.len < 2 || (*obj.buf != '{' && *obj.buf != '[')) {
+    ofs = 0;  // Not an array or object, stop
+  } else {
+    struct mg_str sub = mg_str_n(obj.buf + ofs, obj.len - ofs);
+    if (ofs == 0) ofs++, sub.buf++, sub.len--;
+    if (*obj.buf == '[') {  // Iterate over an array
+      int n = 0, o = mg_json_get(sub, "$", &n);
+      if (n < 0 || o < 0 || (size_t) (o + n) > sub.len) {
+        ofs = 0;  // Error parsing key, stop scanning
+      } else {
+        if (key) *key = mg_str_n(NULL, 0);
+        if (val) *val = mg_str_n(sub.buf + o, (size_t) n);
+        ofs = (size_t) (&sub.buf[o + n] - obj.buf);
+      }
+    } else {  // Iterate over an object
+      int n = 0, o = mg_json_get(sub, "$", &n);
+      if (n < 0 || o < 0 || (size_t) (o + n) > sub.len) {
+        ofs = 0;  // Error parsing key, stop scanning
+      } else {
+        if (key) *key = mg_str_n(sub.buf + o, (size_t) n);
+        sub.buf += o + n, sub.len -= (size_t) (o + n);
+        while (sub.len > 0 && *sub.buf != ':') sub.len--, sub.buf++;
+        if (sub.len > 0 && *sub.buf == ':') sub.len--, sub.buf++;
+        n = 0, o = mg_json_get(sub, "$", &n);
+        if (n < 0 || o < 0 || (size_t) (o + n) > sub.len) {
+          ofs = 0;  // Error parsing value, stop scanning
+        } else {
+          if (val) *val = mg_str_n(sub.buf + o, (size_t) n);
+          ofs = (size_t) (&sub.buf[o + n] - obj.buf);
+        }
+      }
+    }
+    // MG_INFO(("SUB ofs %u %.*s", ofs, sub.len, sub.buf));
+    while (ofs && ofs < obj.len &&
+           (obj.buf[ofs] == ' ' || obj.buf[ofs] == '\t' ||
+            obj.buf[ofs] == '\n' || obj.buf[ofs] == '\r')) {
+      ofs++;
+    }
+    if (ofs && ofs < obj.len && obj.buf[ofs] == ',') ofs++;
+    if (ofs > obj.len) ofs = 0;
+  }
+  return ofs;
+}
+
+int mg_json_get(struct mg_str json, const char *path, int *toklen) {
+  const char *s = json.buf;
+  int len = (int) json.len;
+  enum { S_VALUE, S_KEY, S_COLON, S_COMMA_OR_EOO } expecting = S_VALUE;
+  unsigned char nesting[MG_JSON_MAX_DEPTH];
+  int i = 0;             // Current offset in `s`
+  int j = 0;             // Offset in `s` we're looking for (return value)
+  int depth = 0;         // Current depth (nesting level)
+  int ed = 0;            // Expected depth
+  int pos = 1;           // Current position in `path`
+  int ci = -1, ei = -1;  // Current and expected index in array
+
+  if (toklen) *toklen = 0;
+  if (path[0] != '$') return MG_JSON_INVALID;
+
+#define MG_CHECKRET(x)                                  \
+  do {                                                  \
+    if (depth == ed && path[pos] == '\0' && ci == ei) { \
+      if (toklen) *toklen = i - j + 1;                  \
+      return j;                                         \
+    }                                                   \
+  } while (0)
+
+// In the ascii table, the distance between `[` and `]` is 2.
+// Ditto for `{` and `}`. Hence +2 in the code below.
+#define MG_EOO(x)                                            \
+  do {                                                       \
+    if (depth == ed && ci != ei) return MG_JSON_NOT_FOUND;   \
+    if (c != nesting[depth - 1] + 2) return MG_JSON_INVALID; \
+    depth--;                                                 \
+    MG_CHECKRET(x);                                          \
+  } while (0)
+
+  for (i = 0; i < len; i++) {
+    unsigned char c = ((unsigned char *) s)[i];
+    if (c == ' ' || c == '\t' || c == '\n' || c == '\r') continue;
+    switch (expecting) {
+      case S_VALUE:
+        // p("V %s [%.*s] %d %d %d %d\n", path, pos, path, depth, ed, ci, ei);
+        if (depth == ed) j = i;
+        if (c == '{') {
+          if (depth >= (int) sizeof(nesting)) return MG_JSON_TOO_DEEP;
+          if (depth == ed && path[pos] == '.' && ci == ei) {
+            // If we start the object, reset array indices
+            ed++, pos++, ci = ei = -1;
+          }
+          nesting[depth++] = c;
+          expecting = S_KEY;
+          break;
+        } else if (c == '[') {
+          if (depth >= (int) sizeof(nesting)) return MG_JSON_TOO_DEEP;
+          if (depth == ed && path[pos] == '[' && ei == ci) {
+            ed++, pos++, ci = 0;
+            for (ei = 0; path[pos] != ']' && path[pos] != '\0'; pos++) {
+              ei *= 10;
+              ei += path[pos] - '0';
+            }
+            if (path[pos] != 0) pos++;
+          }
+          nesting[depth++] = c;
+          break;
+        } else if (c == ']' && depth > 0) {  // Empty array
+          MG_EOO(']');
+        } else if (c == 't' && i + 3 < len && memcmp(&s[i], "true", 4) == 0) {
+          i += 3;
+        } else if (c == 'n' && i + 3 < len && memcmp(&s[i], "null", 4) == 0) {
+          i += 3;
+        } else if (c == 'f' && i + 4 < len && memcmp(&s[i], "false", 5) == 0) {
+          i += 4;
+        } else if (c == '-' || ((c >= '0' && c <= '9'))) {
+          int numlen = 0;
+          mg_atod(&s[i], len - i, &numlen);
+          i += numlen - 1;
+        } else if (c == '"') {
+          int n = mg_pass_string(&s[i + 1], len - i - 1);
+          if (n < 0) return n;
+          i += n + 1;
+        } else {
+          return MG_JSON_INVALID;
+        }
+        MG_CHECKRET('V');
+        if (depth == ed && ei >= 0) ci++;
+        expecting = S_COMMA_OR_EOO;
+        break;
+
+      case S_KEY:
+        if (c == '"') {
+          int n = mg_pass_string(&s[i + 1], len - i - 1);
+          if (n < 0) return n;
+          if (i + 1 + n >= len) return MG_JSON_NOT_FOUND;
+          if (depth < ed) return MG_JSON_NOT_FOUND;
+          if (depth == ed && path[pos - 1] != '.') return MG_JSON_NOT_FOUND;
+          // printf("K %s [%.*s] [%.*s] %d %d %d %d %d\n", path, pos, path, n,
+          //        &s[i + 1], n, depth, ed, ci, ei);
+          //  NOTE(cpq): in the check sequence below is important.
+          //  strncmp() must go first: it fails fast if the remaining length
+          //  of the path is smaller than `n`.
+          if (depth == ed && path[pos - 1] == '.' &&
+              strncmp(&s[i + 1], &path[pos], (size_t) n) == 0 &&
+              (path[pos + n] == '\0' || path[pos + n] == '.' ||
+               path[pos + n] == '[')) {
+            pos += n;
+          }
+          i += n + 1;
+          expecting = S_COLON;
+        } else if (c == '}') {  // Empty object
+          MG_EOO('}');
+          expecting = S_COMMA_OR_EOO;
+          if (depth == ed && ei >= 0) ci++;
+        } else {
+          return MG_JSON_INVALID;
+        }
+        break;
+
+      case S_COLON:
+        if (c == ':') {
+          expecting = S_VALUE;
+        } else {
+          return MG_JSON_INVALID;
+        }
+        break;
+
+      case S_COMMA_OR_EOO:
+        if (depth <= 0) {
+          return MG_JSON_INVALID;
+        } else if (c == ',') {
+          expecting = (nesting[depth - 1] == '{') ? S_KEY : S_VALUE;
+        } else if (c == ']' || c == '}') {
+          if (depth == ed && c == '}' && path[pos - 1] == '.')
+            return MG_JSON_NOT_FOUND;
+          if (depth == ed && c == ']' && path[pos - 1] == ',')
+            return MG_JSON_NOT_FOUND;
+          MG_EOO('O');
+          if (depth == ed && ei >= 0) ci++;
+        } else {
+          return MG_JSON_INVALID;
+        }
+        break;
+    }
+  }
+  return MG_JSON_NOT_FOUND;
+}
+
+struct mg_str mg_json_get_tok(struct mg_str json, const char *path) {
+  int len = 0, ofs = mg_json_get(json, path, &len);
+  return mg_str_n(ofs < 0 ? NULL : json.buf + ofs,
+                  (size_t) (len < 0 ? 0 : len));
+}
+
+bool mg_json_get_num(struct mg_str json, const char *path, double *v) {
+  int n, toklen, found = 0;
+  if ((n = mg_json_get(json, path, &toklen)) >= 0 &&
+      (json.buf[n] == '-' || (json.buf[n] >= '0' && json.buf[n] <= '9'))) {
+    if (v != NULL) *v = mg_atod(json.buf + n, toklen, NULL);
+    found = 1;
+  }
+  return found;
+}
+
+bool mg_json_get_bool(struct mg_str json, const char *path, bool *v) {
+  int found = 0, off = mg_json_get(json, path, NULL);
+  if (off >= 0 && (json.buf[off] == 't' || json.buf[off] == 'f')) {
+    if (v != NULL) *v = json.buf[off] == 't';
+    found = 1;
+  }
+  return found;
+}
+
+bool mg_json_unescape(struct mg_str s, char *to, size_t n) {
+  size_t i, j;
+  for (i = 0, j = 0; i < s.len && j < n; i++, j++) {
+    if (s.buf[i] == '\\' && i + 5 < s.len && s.buf[i + 1] == 'u') {
+      //  \uXXXX escape. We process simple one-byte chars \u00xx within ASCII
+      //  range. More complex chars would require dragging in a UTF8 library,
+      //  which is too much for us
+      if (mg_str_to_num(mg_str_n(s.buf + i + 2, 4), 16, &to[j],
+                        sizeof(uint8_t)) == false)
+        return false;
+      i += 5;
+    } else if (s.buf[i] == '\\' && i + 1 < s.len) {
+      char c = json_esc(s.buf[i + 1], 0);
+      if (c == 0) return false;
+      to[j] = c;
+      i++;
+    } else {
+      to[j] = s.buf[i];
+    }
+  }
+  if (j >= n) return false;
+  if (n > 0) to[j] = '\0';
+  return true;
+}
+
+char *mg_json_get_str(struct mg_str json, const char *path) {
+  char *result = NULL;
+  int len = 0, off = mg_json_get(json, path, &len);
+  if (off >= 0 && len > 1 && json.buf[off] == '"') {
+    if ((result = (char *) calloc(1, (size_t) len)) != NULL &&
+        !mg_json_unescape(mg_str_n(json.buf + off + 1, (size_t) (len - 2)),
+                          result, (size_t) len)) {
+      free(result);
+      result = NULL;
+    }
+  }
+  return result;
+}
+
+char *mg_json_get_b64(struct mg_str json, const char *path, int *slen) {
+  char *result = NULL;
+  int len = 0, off = mg_json_get(json, path, &len);
+  if (off >= 0 && json.buf[off] == '"' && len > 1 &&
+      (result = (char *) calloc(1, (size_t) len)) != NULL) {
+    size_t k = mg_base64_decode(json.buf + off + 1, (size_t) (len - 2), result,
+                                (size_t) len);
+    if (slen != NULL) *slen = (int) k;
+  }
+  return result;
+}
+
+char *mg_json_get_hex(struct mg_str json, const char *path, int *slen) {
+  char *result = NULL;
+  int len = 0, off = mg_json_get(json, path, &len);
+  if (off >= 0 && json.buf[off] == '"' && len > 1 &&
+      (result = (char *) calloc(1, (size_t) len / 2)) != NULL) {
+    int i;
+    for (i = 0; i < len - 2; i += 2) {
+      mg_str_to_num(mg_str_n(json.buf + off + 1 + i, 2), 16, &result[i >> 1],
+                    sizeof(uint8_t));
+    }
+    result[len / 2 - 1] = '\0';
+    if (slen != NULL) *slen = len / 2 - 1;
+  }
+  return result;
+}
+
+long mg_json_get_long(struct mg_str json, const char *path, long dflt) {
+  double dv;
+  long result = dflt;
+  if (mg_json_get_num(json, path, &dv)) result = (long) dv;
+  return result;
+}
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/log.c"
+#endif
+
+
+
+
+
+int mg_log_level = MG_LL_INFO;
+static mg_pfn_t s_log_func = mg_pfn_stdout;
+static void *s_log_func_param = NULL;
+
+void mg_log_set_fn(mg_pfn_t fn, void *param) {
+  s_log_func = fn;
+  s_log_func_param = param;
+}
+
+static void logc(unsigned char c) {
+  s_log_func((char) c, s_log_func_param);
+}
+
+static void logs(const char *buf, size_t len) {
+  size_t i;
+  for (i = 0; i < len; i++) logc(((unsigned char *) buf)[i]);
+}
+
+#if MG_ENABLE_CUSTOM_LOG
+// Let user define their own mg_log_prefix() and mg_log()
+#else
+void mg_log_prefix(int level, const char *file, int line, const char *fname) {
+  const char *p = strrchr(file, '/');
+  char buf[41];
+  size_t n;
+  if (p == NULL) p = strrchr(file, '\\');
+  n = mg_snprintf(buf, sizeof(buf), "%-6llx %d %s:%d:%s", mg_millis(), level,
+                  p == NULL ? file : p + 1, line, fname);
+  if (n > sizeof(buf) - 2) n = sizeof(buf) - 2;
+  while (n < sizeof(buf)) buf[n++] = ' ';
+  logs(buf, n - 1);
+}
+
+void mg_log(const char *fmt, ...) {
+  va_list ap;
+  va_start(ap, fmt);
+  mg_vxprintf(s_log_func, s_log_func_param, fmt, &ap);
+  va_end(ap);
+  logs("\r\n", 2);
+}
+#endif
+
+static unsigned char nibble(unsigned c) {
+  return (unsigned char) (c < 10 ? c + '0' : c + 'W');
+}
+
+#define ISPRINT(x) ((x) >= ' ' && (x) <= '~')
+void mg_hexdump(const void *buf, size_t len) {
+  const unsigned char *p = (const unsigned char *) buf;
+  unsigned char ascii[16], alen = 0;
+  size_t i;
+  for (i = 0; i < len; i++) {
+    if ((i % 16) == 0) {
+      // Print buffered ascii chars
+      if (i > 0) logs("  ", 2), logs((char *) ascii, 16), logc('\n'), alen = 0;
+      // Print hex address, then \t
+      logc(nibble((i >> 12) & 15)), logc(nibble((i >> 8) & 15)),
+          logc(nibble((i >> 4) & 15)), logc('0'), logs("   ", 3);
+    }
+    logc(nibble(p[i] >> 4)), logc(nibble(p[i] & 15));  // Two nibbles, e.g. c5
+    logc(' ');                                         // Space after hex number
+    ascii[alen++] = ISPRINT(p[i]) ? p[i] : '.';        // Add to the ascii buf
+  }
+  while (alen < 16) logs("   ", 3), ascii[alen++] = ' ';
+  logs("  ", 2), logs((char *) ascii, 16), logc('\n');
+}
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/md5.c"
+#endif
+
+
+
+//  This code implements the MD5 message-digest algorithm.
+//  The algorithm is due to Ron Rivest.  This code was
+//  written by Colin Plumb in 1993, no copyright is claimed.
+//  This code is in the public domain; do with it what you wish.
+//
+//  Equivalent code is available from RSA Data Security, Inc.
+//  This code has been tested against that, and is equivalent,
+//  except that you don't need to include two pages of legalese
+//  with every copy.
+//
+//  To compute the message digest of a chunk of bytes, declare an
+//  MD5Context structure, pass it to MD5Init, call MD5Update as
+//  needed on buffers full of bytes, and then call MD5Final, which
+//  will fill a supplied 16-byte array with the digest.
+
+#if defined(MG_ENABLE_MD5) && MG_ENABLE_MD5
+
+static void mg_byte_reverse(unsigned char *buf, unsigned longs) {
+  if (MG_BIG_ENDIAN) {
+    do {
+      uint32_t t = (uint32_t) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
+                   ((unsigned) buf[1] << 8 | buf[0]);
+      *(uint32_t *) buf = t;
+      buf += 4;
+    } while (--longs);
+  } else {
+    (void) buf, (void) longs;  // Little endian. Do nothing
+  }
+}
+
+#define F1(x, y, z) (z ^ (x & (y ^ z)))
+#define F2(x, y, z) F1(z, x, y)
+#define F3(x, y, z) (x ^ y ^ z)
+#define F4(x, y, z) (y ^ (x | ~z))
+
+#define MD5STEP(f, w, x, y, z, data, s) \
+  (w += f(x, y, z) + data, w = w << s | w >> (32 - s), w += x)
+
+/*
+ * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
+ * initialization constants.
+ */
+void mg_md5_init(mg_md5_ctx *ctx) {
+  ctx->buf[0] = 0x67452301;
+  ctx->buf[1] = 0xefcdab89;
+  ctx->buf[2] = 0x98badcfe;
+  ctx->buf[3] = 0x10325476;
+
+  ctx->bits[0] = 0;
+  ctx->bits[1] = 0;
+}
+
+static void mg_md5_transform(uint32_t buf[4], uint32_t const in[16]) {
+  uint32_t a, b, c, d;
+
+  a = buf[0];
+  b = buf[1];
+  c = buf[2];
+  d = buf[3];
+
+  MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
+  MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
+  MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
+  MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
+  MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
+  MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
+  MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
+  MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
+  MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
+  MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
+  MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
+  MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
+  MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
+  MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
+  MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
+  MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
+
+  MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
+  MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
+  MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
+  MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
+  MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
+  MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
+  MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
+  MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
+  MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
+  MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
+  MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
+  MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
+  MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
+  MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
+  MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
+  MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
+
+  MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
+  MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
+  MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
+  MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
+  MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
+  MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
+  MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
+  MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
+  MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
+  MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
+  MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
+  MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
+  MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
+  MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
+  MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
+  MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
+
+  MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
+  MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
+  MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
+  MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
+  MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
+  MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
+  MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
+  MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
+  MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
+  MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
+  MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
+  MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
+  MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
+  MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
+  MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
+  MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
+
+  buf[0] += a;
+  buf[1] += b;
+  buf[2] += c;
+  buf[3] += d;
+}
+
+void mg_md5_update(mg_md5_ctx *ctx, const unsigned char *buf, size_t len) {
+  uint32_t t;
+
+  t = ctx->bits[0];
+  if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t) ctx->bits[1]++;
+  ctx->bits[1] += (uint32_t) len >> 29;
+
+  t = (t >> 3) & 0x3f;
+
+  if (t) {
+    unsigned char *p = (unsigned char *) ctx->in + t;
+
+    t = 64 - t;
+    if (len < t) {
+      memcpy(p, buf, len);
+      return;
+    }
+    memcpy(p, buf, t);
+    mg_byte_reverse(ctx->in, 16);
+    mg_md5_transform(ctx->buf, (uint32_t *) ctx->in);
+    buf += t;
+    len -= t;
+  }
+
+  while (len >= 64) {
+    memcpy(ctx->in, buf, 64);
+    mg_byte_reverse(ctx->in, 16);
+    mg_md5_transform(ctx->buf, (uint32_t *) ctx->in);
+    buf += 64;
+    len -= 64;
+  }
+
+  memcpy(ctx->in, buf, len);
+}
+
+void mg_md5_final(mg_md5_ctx *ctx, unsigned char digest[16]) {
+  unsigned count;
+  unsigned char *p;
+  uint32_t *a;
+
+  count = (ctx->bits[0] >> 3) & 0x3F;
+
+  p = ctx->in + count;
+  *p++ = 0x80;
+  count = 64 - 1 - count;
+  if (count < 8) {
+    memset(p, 0, count);
+    mg_byte_reverse(ctx->in, 16);
+    mg_md5_transform(ctx->buf, (uint32_t *) ctx->in);
+    memset(ctx->in, 0, 56);
+  } else {
+    memset(p, 0, count - 8);
+  }
+  mg_byte_reverse(ctx->in, 14);
+
+  a = (uint32_t *) ctx->in;
+  a[14] = ctx->bits[0];
+  a[15] = ctx->bits[1];
+
+  mg_md5_transform(ctx->buf, (uint32_t *) ctx->in);
+  mg_byte_reverse((unsigned char *) ctx->buf, 4);
+  memcpy(digest, ctx->buf, 16);
+  memset((char *) ctx, 0, sizeof(*ctx));
+}
+#endif
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/mqtt.c"
+#endif
+
+
+
+
+
+
+
+
+#define MQTT_CLEAN_SESSION 0x02
+#define MQTT_HAS_WILL 0x04
+#define MQTT_WILL_RETAIN 0x20
+#define MQTT_HAS_PASSWORD 0x40
+#define MQTT_HAS_USER_NAME 0x80
+
+struct mg_mqtt_pmap {
+  uint8_t id;
+  uint8_t type;
+};
+
+static const struct mg_mqtt_pmap s_prop_map[] = {
+    {MQTT_PROP_PAYLOAD_FORMAT_INDICATOR, MQTT_PROP_TYPE_BYTE},
+    {MQTT_PROP_MESSAGE_EXPIRY_INTERVAL, MQTT_PROP_TYPE_INT},
+    {MQTT_PROP_CONTENT_TYPE, MQTT_PROP_TYPE_STRING},
+    {MQTT_PROP_RESPONSE_TOPIC, MQTT_PROP_TYPE_STRING},
+    {MQTT_PROP_CORRELATION_DATA, MQTT_PROP_TYPE_BINARY_DATA},
+    {MQTT_PROP_SUBSCRIPTION_IDENTIFIER, MQTT_PROP_TYPE_VARIABLE_INT},
+    {MQTT_PROP_SESSION_EXPIRY_INTERVAL, MQTT_PROP_TYPE_INT},
+    {MQTT_PROP_ASSIGNED_CLIENT_IDENTIFIER, MQTT_PROP_TYPE_STRING},
+    {MQTT_PROP_SERVER_KEEP_ALIVE, MQTT_PROP_TYPE_SHORT},
+    {MQTT_PROP_AUTHENTICATION_METHOD, MQTT_PROP_TYPE_STRING},
+    {MQTT_PROP_AUTHENTICATION_DATA, MQTT_PROP_TYPE_BINARY_DATA},
+    {MQTT_PROP_REQUEST_PROBLEM_INFORMATION, MQTT_PROP_TYPE_BYTE},
+    {MQTT_PROP_WILL_DELAY_INTERVAL, MQTT_PROP_TYPE_INT},
+    {MQTT_PROP_REQUEST_RESPONSE_INFORMATION, MQTT_PROP_TYPE_BYTE},
+    {MQTT_PROP_RESPONSE_INFORMATION, MQTT_PROP_TYPE_STRING},
+    {MQTT_PROP_SERVER_REFERENCE, MQTT_PROP_TYPE_STRING},
+    {MQTT_PROP_REASON_STRING, MQTT_PROP_TYPE_STRING},
+    {MQTT_PROP_RECEIVE_MAXIMUM, MQTT_PROP_TYPE_SHORT},
+    {MQTT_PROP_TOPIC_ALIAS_MAXIMUM, MQTT_PROP_TYPE_SHORT},
+    {MQTT_PROP_TOPIC_ALIAS, MQTT_PROP_TYPE_SHORT},
+    {MQTT_PROP_MAXIMUM_QOS, MQTT_PROP_TYPE_BYTE},
+    {MQTT_PROP_RETAIN_AVAILABLE, MQTT_PROP_TYPE_BYTE},
+    {MQTT_PROP_USER_PROPERTY, MQTT_PROP_TYPE_STRING_PAIR},
+    {MQTT_PROP_MAXIMUM_PACKET_SIZE, MQTT_PROP_TYPE_INT},
+    {MQTT_PROP_WILDCARD_SUBSCRIPTION_AVAILABLE, MQTT_PROP_TYPE_BYTE},
+    {MQTT_PROP_SUBSCRIPTION_IDENTIFIER_AVAILABLE, MQTT_PROP_TYPE_BYTE},
+    {MQTT_PROP_SHARED_SUBSCRIPTION_AVAILABLE, MQTT_PROP_TYPE_BYTE}};
+
+void mg_mqtt_send_header(struct mg_connection *c, uint8_t cmd, uint8_t flags,
+                         uint32_t len) {
+  uint8_t buf[1 + sizeof(len)], *vlen = &buf[1];
+  buf[0] = (uint8_t) ((cmd << 4) | flags);
+  do {
+    *vlen = len % 0x80;
+    len /= 0x80;
+    if (len > 0) *vlen |= 0x80;
+    vlen++;
+  } while (len > 0 && vlen < &buf[sizeof(buf)]);
+  mg_send(c, buf, (size_t) (vlen - buf));
+}
+
+static void mg_send_u16(struct mg_connection *c, uint16_t value) {
+  mg_send(c, &value, sizeof(value));
+}
+
+static void mg_send_u32(struct mg_connection *c, uint32_t value) {
+  mg_send(c, &value, sizeof(value));
+}
+
+static uint8_t varint_size(size_t length) {
+  uint8_t bytes_needed = 0;
+  do {
+    bytes_needed++;
+    length /= 0x80;
+  } while (length > 0);
+  return bytes_needed;
+}
+
+static size_t encode_varint(uint8_t *buf, size_t value) {
+  size_t len = 0;
+
+  do {
+    uint8_t b = (uint8_t) (value % 128);
+    value /= 128;
+    if (value > 0) b |= 0x80;
+    buf[len++] = b;
+  } while (value > 0);
+
+  return len;
+}
+
+static size_t decode_varint(const uint8_t *buf, size_t len, size_t *value) {
+  size_t multiplier = 1, offset;
+  *value = 0;
+
+  for (offset = 0; offset < 4 && offset < len; offset++) {
+    uint8_t encoded_byte = buf[offset];
+    *value += (encoded_byte & 0x7f) * multiplier;
+    multiplier *= 128;
+
+    if ((encoded_byte & 0x80) == 0) return offset + 1;
+  }
+
+  return 0;
+}
+
+static int mqtt_prop_type_by_id(uint8_t prop_id) {
+  size_t i, num_properties = sizeof(s_prop_map) / sizeof(s_prop_map[0]);
+  for (i = 0; i < num_properties; ++i) {
+    if (s_prop_map[i].id == prop_id) return s_prop_map[i].type;
+  }
+  return -1;  // Property ID not found
+}
+
+// Returns the size of the properties section, without the
+// size of the content's length
+static size_t get_properties_length(struct mg_mqtt_prop *props, size_t count) {
+  size_t i, size = 0;
+  for (i = 0; i < count; i++) {
+    size++;  // identifier
+    switch (mqtt_prop_type_by_id(props[i].id)) {
+      case MQTT_PROP_TYPE_STRING_PAIR:
+        size += (uint32_t) (props[i].val.len + props[i].key.len +
+                            2 * sizeof(uint16_t));
+        break;
+      case MQTT_PROP_TYPE_STRING:
+        size += (uint32_t) (props[i].val.len + sizeof(uint16_t));
+        break;
+      case MQTT_PROP_TYPE_BINARY_DATA:
+        size += (uint32_t) (props[i].val.len + sizeof(uint16_t));
+        break;
+      case MQTT_PROP_TYPE_VARIABLE_INT:
+        size += varint_size((uint32_t) props[i].iv);
+        break;
+      case MQTT_PROP_TYPE_INT:
+        size += (uint32_t) sizeof(uint32_t);
+        break;
+      case MQTT_PROP_TYPE_SHORT:
+        size += (uint32_t) sizeof(uint16_t);
+        break;
+      case MQTT_PROP_TYPE_BYTE:
+        size += (uint32_t) sizeof(uint8_t);
+        break;
+      default:
+        return size;  // cannot parse further down
+    }
+  }
+
+  return size;
+}
+
+// returns the entire size of the properties section, including the
+// size of the variable length of the content
+static size_t get_props_size(struct mg_mqtt_prop *props, size_t count) {
+  size_t size = get_properties_length(props, count);
+  size += varint_size(size);
+  return size;
+}
+
+static void mg_send_mqtt_properties(struct mg_connection *c,
+                                    struct mg_mqtt_prop *props, size_t nprops) {
+  size_t total_size = get_properties_length(props, nprops);
+  uint8_t buf_v[4] = {0, 0, 0, 0};
+  uint8_t buf[4] = {0, 0, 0, 0};
+  size_t i, len = encode_varint(buf, total_size);
+
+  mg_send(c, buf, (size_t) len);
+  for (i = 0; i < nprops; i++) {
+    mg_send(c, &props[i].id, sizeof(props[i].id));
+    switch (mqtt_prop_type_by_id(props[i].id)) {
+      case MQTT_PROP_TYPE_STRING_PAIR:
+        mg_send_u16(c, mg_htons((uint16_t) props[i].key.len));
+        mg_send(c, props[i].key.buf, props[i].key.len);
+        mg_send_u16(c, mg_htons((uint16_t) props[i].val.len));
+        mg_send(c, props[i].val.buf, props[i].val.len);
+        break;
+      case MQTT_PROP_TYPE_BYTE:
+        mg_send(c, &props[i].iv, sizeof(uint8_t));
+        break;
+      case MQTT_PROP_TYPE_SHORT:
+        mg_send_u16(c, mg_htons((uint16_t) props[i].iv));
+        break;
+      case MQTT_PROP_TYPE_INT:
+        mg_send_u32(c, mg_htonl((uint32_t) props[i].iv));
+        break;
+      case MQTT_PROP_TYPE_STRING:
+        mg_send_u16(c, mg_htons((uint16_t) props[i].val.len));
+        mg_send(c, props[i].val.buf, props[i].val.len);
+        break;
+      case MQTT_PROP_TYPE_BINARY_DATA:
+        mg_send_u16(c, mg_htons((uint16_t) props[i].val.len));
+        mg_send(c, props[i].val.buf, props[i].val.len);
+        break;
+      case MQTT_PROP_TYPE_VARIABLE_INT:
+        len = encode_varint(buf_v, props[i].iv);
+        mg_send(c, buf_v, (size_t) len);
+        break;
+    }
+  }
+}
+
+size_t mg_mqtt_next_prop(struct mg_mqtt_message *msg, struct mg_mqtt_prop *prop,
+                         size_t ofs) {
+  uint8_t *i = (uint8_t *) msg->dgram.buf + msg->props_start + ofs;
+  uint8_t *end = (uint8_t *) msg->dgram.buf + msg->dgram.len;
+  size_t new_pos = ofs, len;
+  prop->id = i[0];
+
+  if (ofs >= msg->dgram.len || ofs >= msg->props_start + msg->props_size)
+    return 0;
+  i++, new_pos++;
+
+  switch (mqtt_prop_type_by_id(prop->id)) {
+    case MQTT_PROP_TYPE_STRING_PAIR:
+      prop->key.len = (uint16_t) ((((uint16_t) i[0]) << 8) | i[1]);
+      prop->key.buf = (char *) i + 2;
+      i += 2 + prop->key.len;
+      prop->val.len = (uint16_t) ((((uint16_t) i[0]) << 8) | i[1]);
+      prop->val.buf = (char *) i + 2;
+      new_pos += 2 * sizeof(uint16_t) + prop->val.len + prop->key.len;
+      break;
+    case MQTT_PROP_TYPE_BYTE:
+      prop->iv = (uint8_t) i[0];
+      new_pos++;
+      break;
+    case MQTT_PROP_TYPE_SHORT:
+      prop->iv = (uint16_t) ((((uint16_t) i[0]) << 8) | i[1]);
+      new_pos += sizeof(uint16_t);
+      break;
+    case MQTT_PROP_TYPE_INT:
+      prop->iv = ((uint32_t) i[0] << 24) | ((uint32_t) i[1] << 16) |
+                 ((uint32_t) i[2] << 8) | i[3];
+      new_pos += sizeof(uint32_t);
+      break;
+    case MQTT_PROP_TYPE_STRING:
+      prop->val.len = (uint16_t) ((((uint16_t) i[0]) << 8) | i[1]);
+      prop->val.buf = (char *) i + 2;
+      new_pos += 2 + prop->val.len;
+      break;
+    case MQTT_PROP_TYPE_BINARY_DATA:
+      prop->val.len = (uint16_t) ((((uint16_t) i[0]) << 8) | i[1]);
+      prop->val.buf = (char *) i + 2;
+      new_pos += 2 + prop->val.len;
+      break;
+    case MQTT_PROP_TYPE_VARIABLE_INT:
+      len = decode_varint(i, (size_t) (end - i), (size_t *) &prop->iv);
+      new_pos = (!len) ? 0 : new_pos + len;
+      break;
+    default:
+      new_pos = 0;
+  }
+
+  return new_pos;
+}
+
+void mg_mqtt_login(struct mg_connection *c, const struct mg_mqtt_opts *opts) {
+  char client_id[21];
+  struct mg_str cid = opts->client_id;
+  size_t total_len = 7 + 1 + 2 + 2;
+  uint8_t hdr[8] = {0, 4, 'M', 'Q', 'T', 'T', opts->version, 0};
+
+  if (cid.len == 0) {
+    mg_random_str(client_id, sizeof(client_id) - 1);
+    client_id[sizeof(client_id) - 1] = '\0';
+    cid = mg_str(client_id);
+  }
+
+  if (hdr[6] == 0) hdr[6] = 4;  // If version is not set, use 4 (3.1.1)
+  c->is_mqtt5 = hdr[6] == 5;    // Set version 5 flag
+  hdr[7] = (uint8_t) ((opts->qos & 3) << 3);  // Connection flags
+  if (opts->user.len > 0) {
+    total_len += 2 + (uint32_t) opts->user.len;
+    hdr[7] |= MQTT_HAS_USER_NAME;
+  }
+  if (opts->pass.len > 0) {
+    total_len += 2 + (uint32_t) opts->pass.len;
+    hdr[7] |= MQTT_HAS_PASSWORD;
+  }
+  if (opts->topic.len > 0) { // allow zero-length msgs, message.len is size_t
+    total_len += 4 + (uint32_t) opts->topic.len + (uint32_t) opts->message.len;
+    hdr[7] |= MQTT_HAS_WILL;
+  }
+  if (opts->clean || cid.len == 0) hdr[7] |= MQTT_CLEAN_SESSION;
+  if (opts->retain) hdr[7] |= MQTT_WILL_RETAIN;
+  total_len += (uint32_t) cid.len;
+  if (c->is_mqtt5) {
+    total_len += get_props_size(opts->props, opts->num_props);
+    if (hdr[7] & MQTT_HAS_WILL)
+      total_len += get_props_size(opts->will_props, opts->num_will_props);
+  }
+
+  mg_mqtt_send_header(c, MQTT_CMD_CONNECT, 0, (uint32_t) total_len);
+  mg_send(c, hdr, sizeof(hdr));
+  // keepalive == 0 means "do not disconnect us!"
+  mg_send_u16(c, mg_htons((uint16_t) opts->keepalive));
+
+  if (c->is_mqtt5) mg_send_mqtt_properties(c, opts->props, opts->num_props);
+
+  mg_send_u16(c, mg_htons((uint16_t) cid.len));
+  mg_send(c, cid.buf, cid.len);
+
+  if (hdr[7] & MQTT_HAS_WILL) {
+    if (c->is_mqtt5)
+      mg_send_mqtt_properties(c, opts->will_props, opts->num_will_props);
+
+    mg_send_u16(c, mg_htons((uint16_t) opts->topic.len));
+    mg_send(c, opts->topic.buf, opts->topic.len);
+    mg_send_u16(c, mg_htons((uint16_t) opts->message.len));
+    mg_send(c, opts->message.buf, opts->message.len);
+  }
+  if (opts->user.len > 0) {
+    mg_send_u16(c, mg_htons((uint16_t) opts->user.len));
+    mg_send(c, opts->user.buf, opts->user.len);
+  }
+  if (opts->pass.len > 0) {
+    mg_send_u16(c, mg_htons((uint16_t) opts->pass.len));
+    mg_send(c, opts->pass.buf, opts->pass.len);
+  }
+}
+
+uint16_t mg_mqtt_pub(struct mg_connection *c, const struct mg_mqtt_opts *opts) {
+  uint16_t id = opts->retransmit_id;
+  uint8_t flags = (uint8_t) (((opts->qos & 3) << 1) | (opts->retain ? 1 : 0));
+  size_t len = 2 + opts->topic.len + opts->message.len;
+  MG_DEBUG(("%lu [%.*s] -> [%.*s]", c->id, (int) opts->topic.len,
+            (char *) opts->topic.buf, (int) opts->message.len,
+            (char *) opts->message.buf));
+  if (opts->qos > 0) len += 2;
+  if (c->is_mqtt5) len += get_props_size(opts->props, opts->num_props);
+
+  if (opts->qos > 0 && id != 0) flags |= 1 << 3;
+  mg_mqtt_send_header(c, MQTT_CMD_PUBLISH, flags, (uint32_t) len);
+  mg_send_u16(c, mg_htons((uint16_t) opts->topic.len));
+  mg_send(c, opts->topic.buf, opts->topic.len);
+  if (opts->qos > 0) {    // need to send 'id' field
+    if (id == 0) {  // generate new one if not resending
+      if (++c->mgr->mqtt_id == 0) ++c->mgr->mqtt_id;
+      id = c->mgr->mqtt_id;
+    }
+    mg_send_u16(c, mg_htons(id));
+  }
+
+  if (c->is_mqtt5) mg_send_mqtt_properties(c, opts->props, opts->num_props);
+
+  if (opts->message.len > 0) mg_send(c, opts->message.buf, opts->message.len);
+  return id;
+}
+
+void mg_mqtt_sub(struct mg_connection *c, const struct mg_mqtt_opts *opts) {
+  uint8_t qos_ = opts->qos & 3;
+  size_t plen = c->is_mqtt5 ? get_props_size(opts->props, opts->num_props) : 0;
+  size_t len = 2 + opts->topic.len + 2 + 1 + plen;
+
+  mg_mqtt_send_header(c, MQTT_CMD_SUBSCRIBE, 2, (uint32_t) len);
+  if (++c->mgr->mqtt_id == 0) ++c->mgr->mqtt_id;
+  mg_send_u16(c, mg_htons(c->mgr->mqtt_id));
+  if (c->is_mqtt5) mg_send_mqtt_properties(c, opts->props, opts->num_props);
+
+  mg_send_u16(c, mg_htons((uint16_t) opts->topic.len));
+  mg_send(c, opts->topic.buf, opts->topic.len);
+  mg_send(c, &qos_, sizeof(qos_));
+}
+
+int mg_mqtt_parse(const uint8_t *buf, size_t len, uint8_t version,
+                  struct mg_mqtt_message *m) {
+  uint8_t lc = 0, *p, *end;
+  uint32_t n = 0, len_len = 0;
+
+  memset(m, 0, sizeof(*m));
+  m->dgram.buf = (char *) buf;
+  if (len < 2) return MQTT_INCOMPLETE;
+  m->cmd = (uint8_t) (buf[0] >> 4);
+  m->qos = (buf[0] >> 1) & 3;
+
+  n = len_len = 0;
+  p = (uint8_t *) buf + 1;
+  while ((size_t) (p - buf) < len) {
+    lc = *((uint8_t *) p++);
+    n += (uint32_t) ((lc & 0x7f) << 7 * len_len);
+    len_len++;
+    if (!(lc & 0x80)) break;
+    if (len_len >= 4) return MQTT_MALFORMED;
+  }
+  end = p + n;
+  if ((lc & 0x80) || (end > buf + len)) return MQTT_INCOMPLETE;
+  m->dgram.len = (size_t) (end - buf);
+
+  switch (m->cmd) {
+    case MQTT_CMD_CONNACK:
+      if (end - p < 2) return MQTT_MALFORMED;
+      m->ack = p[1];
+      break;
+    case MQTT_CMD_PUBACK:
+    case MQTT_CMD_PUBREC:
+    case MQTT_CMD_PUBREL:
+    case MQTT_CMD_PUBCOMP:
+    case MQTT_CMD_SUBSCRIBE:
+    case MQTT_CMD_SUBACK:
+    case MQTT_CMD_UNSUBSCRIBE:
+    case MQTT_CMD_UNSUBACK:
+      if (p + 2 > end) return MQTT_MALFORMED;
+      m->id = (uint16_t) ((((uint16_t) p[0]) << 8) | p[1]);
+      p += 2;
+      break;
+    case MQTT_CMD_PUBLISH: {
+      if (p + 2 > end) return MQTT_MALFORMED;
+      m->topic.len = (uint16_t) ((((uint16_t) p[0]) << 8) | p[1]);
+      m->topic.buf = (char *) p + 2;
+      p += 2 + m->topic.len;
+      if (p > end) return MQTT_MALFORMED;
+      if (m->qos > 0) {
+        if (p + 2 > end) return MQTT_MALFORMED;
+        m->id = (uint16_t) ((((uint16_t) p[0]) << 8) | p[1]);
+        p += 2;
+      }
+      if (p > end) return MQTT_MALFORMED;
+      if (version == 5 && p + 2 < end) {
+        len_len =
+            (uint32_t) decode_varint(p, (size_t) (end - p), &m->props_size);
+        if (!len_len) return MQTT_MALFORMED;
+        m->props_start = (size_t) (p + len_len - buf);
+        p += len_len + m->props_size;
+      }
+      if (p > end) return MQTT_MALFORMED;
+      m->data.buf = (char *) p;
+      m->data.len = (size_t) (end - p);
+      break;
+    }
+    default:
+      break;
+  }
+  return MQTT_OK;
+}
+
+static void mqtt_cb(struct mg_connection *c, int ev, void *ev_data) {
+  if (ev == MG_EV_READ) {
+    for (;;) {
+      uint8_t version = c->is_mqtt5 ? 5 : 4;
+      struct mg_mqtt_message mm;
+      int rc = mg_mqtt_parse(c->recv.buf, c->recv.len, version, &mm);
+      if (rc == MQTT_MALFORMED) {
+        MG_ERROR(("%lu MQTT malformed message", c->id));
+        c->is_closing = 1;
+        break;
+      } else if (rc == MQTT_OK) {
+        MG_VERBOSE(("%lu MQTT CMD %d len %d [%.*s]", c->id, mm.cmd,
+                    (int) mm.dgram.len, (int) mm.data.len, mm.data.buf));
+        switch (mm.cmd) {
+          case MQTT_CMD_CONNACK:
+            mg_call(c, MG_EV_MQTT_OPEN, &mm.ack);
+            if (mm.ack == 0) {
+              MG_DEBUG(("%lu Connected", c->id));
+            } else {
+              MG_ERROR(("%lu MQTT auth failed, code %d", c->id, mm.ack));
+              c->is_closing = 1;
+            }
+            break;
+          case MQTT_CMD_PUBLISH: {
+            /*MG_DEBUG(("%lu [%.*s] -> [%.*s]", c->id, (int) mm.topic.len,
+                      mm.topic.buf, (int) mm.data.len, mm.data.buf));*/
+            if (mm.qos > 0) {
+              uint16_t id = mg_ntohs(mm.id);
+              uint32_t remaining_len = sizeof(id);
+              if (c->is_mqtt5) remaining_len += 2;  // 3.4.2
+
+              mg_mqtt_send_header(
+                  c,
+                  (uint8_t) (mm.qos == 2 ? MQTT_CMD_PUBREC : MQTT_CMD_PUBACK),
+                  0, remaining_len);
+              mg_send(c, &id, sizeof(id));
+
+              if (c->is_mqtt5) {
+                uint16_t zero = 0;
+                mg_send(c, &zero, sizeof(zero));
+              }
+            }
+            mg_call(c, MG_EV_MQTT_MSG, &mm);  // let the app handle qos stuff
+            break;
+          }
+          case MQTT_CMD_PUBREC: {  // MQTT5: 3.5.2-1 TODO(): variable header rc
+            uint16_t id = mg_ntohs(mm.id);
+            uint32_t remaining_len = sizeof(id);  // MQTT5 3.6.2-1
+            mg_mqtt_send_header(c, MQTT_CMD_PUBREL, 2, remaining_len);
+            mg_send(c, &id, sizeof(id));  // MQTT5 3.6.1-1, flags = 2
+            break;
+          }
+          case MQTT_CMD_PUBREL: {  // MQTT5: 3.6.2-1 TODO(): variable header rc
+            uint16_t id = mg_ntohs(mm.id);
+            uint32_t remaining_len = sizeof(id);  // MQTT5 3.7.2-1
+            mg_mqtt_send_header(c, MQTT_CMD_PUBCOMP, 0, remaining_len);
+            mg_send(c, &id, sizeof(id));
+            break;
+          }
+        }
+        mg_call(c, MG_EV_MQTT_CMD, &mm);
+        mg_iobuf_del(&c->recv, 0, mm.dgram.len);
+      } else {
+        break;
+      }
+    }
+  }
+  (void) ev_data;
+}
+
+void mg_mqtt_ping(struct mg_connection *nc) {
+  mg_mqtt_send_header(nc, MQTT_CMD_PINGREQ, 0, 0);
+}
+
+void mg_mqtt_pong(struct mg_connection *nc) {
+  mg_mqtt_send_header(nc, MQTT_CMD_PINGRESP, 0, 0);
+}
+
+void mg_mqtt_disconnect(struct mg_connection *c,
+                        const struct mg_mqtt_opts *opts) {
+  size_t len = 0;
+  if (c->is_mqtt5) len = 1 + get_props_size(opts->props, opts->num_props);
+  mg_mqtt_send_header(c, MQTT_CMD_DISCONNECT, 0, (uint32_t) len);
+
+  if (c->is_mqtt5) {
+    uint8_t zero = 0;
+    mg_send(c, &zero, sizeof(zero));  // reason code
+    mg_send_mqtt_properties(c, opts->props, opts->num_props);
+  }
+}
+
+struct mg_connection *mg_mqtt_connect(struct mg_mgr *mgr, const char *url,
+                                      const struct mg_mqtt_opts *opts,
+                                      mg_event_handler_t fn, void *fn_data) {
+  struct mg_connection *c = mg_connect(mgr, url, fn, fn_data);
+  if (c != NULL) {
+    struct mg_mqtt_opts empty;
+    memset(&empty, 0, sizeof(empty));
+    mg_mqtt_login(c, opts == NULL ? &empty : opts);
+    c->pfn = mqtt_cb;
+  }
+  return c;
+}
+
+struct mg_connection *mg_mqtt_listen(struct mg_mgr *mgr, const char *url,
+                                     mg_event_handler_t fn, void *fn_data) {
+  struct mg_connection *c = mg_listen(mgr, url, fn, fn_data);
+  if (c != NULL) c->pfn = mqtt_cb, c->pfn_data = mgr;
+  return c;
+}
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/net.c"
+#endif
+
+
+
+
+
+
+
+
+
+size_t mg_vprintf(struct mg_connection *c, const char *fmt, va_list *ap) {
+  size_t old = c->send.len;
+  mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, ap);
+  return c->send.len - old;
+}
+
+size_t mg_printf(struct mg_connection *c, const char *fmt, ...) {
+  size_t len = 0;
+  va_list ap;
+  va_start(ap, fmt);
+  len = mg_vprintf(c, fmt, &ap);
+  va_end(ap);
+  return len;
+}
+
+static bool mg_atonl(struct mg_str str, struct mg_addr *addr) {
+  uint32_t localhost = mg_htonl(0x7f000001);
+  if (mg_strcasecmp(str, mg_str("localhost")) != 0) return false;
+  memcpy(addr->ip, &localhost, sizeof(uint32_t));
+  addr->is_ip6 = false;
+  return true;
+}
+
+static bool mg_atone(struct mg_str str, struct mg_addr *addr) {
+  if (str.len > 0) return false;
+  memset(addr->ip, 0, sizeof(addr->ip));
+  addr->is_ip6 = false;
+  return true;
+}
+
+static bool mg_aton4(struct mg_str str, struct mg_addr *addr) {
+  uint8_t data[4] = {0, 0, 0, 0};
+  size_t i, num_dots = 0;
+  for (i = 0; i < str.len; i++) {
+    if (str.buf[i] >= '0' && str.buf[i] <= '9') {
+      int octet = data[num_dots] * 10 + (str.buf[i] - '0');
+      if (octet > 255) return false;
+      data[num_dots] = (uint8_t) octet;
+    } else if (str.buf[i] == '.') {
+      if (num_dots >= 3 || i == 0 || str.buf[i - 1] == '.') return false;
+      num_dots++;
+    } else {
+      return false;
+    }
+  }
+  if (num_dots != 3 || str.buf[i - 1] == '.') return false;
+  memcpy(&addr->ip, data, sizeof(data));
+  addr->is_ip6 = false;
+  return true;
+}
+
+static bool mg_v4mapped(struct mg_str str, struct mg_addr *addr) {
+  int i;
+  uint32_t ipv4;
+  if (str.len < 14) return false;
+  if (str.buf[0] != ':' || str.buf[1] != ':' || str.buf[6] != ':') return false;
+  for (i = 2; i < 6; i++) {
+    if (str.buf[i] != 'f' && str.buf[i] != 'F') return false;
+  }
+  // struct mg_str s = mg_str_n(&str.buf[7], str.len - 7);
+  if (!mg_aton4(mg_str_n(&str.buf[7], str.len - 7), addr)) return false;
+  memcpy(&ipv4, addr->ip, sizeof(ipv4));
+  memset(addr->ip, 0, sizeof(addr->ip));
+  addr->ip[10] = addr->ip[11] = 255;
+  memcpy(&addr->ip[12], &ipv4, 4);
+  addr->is_ip6 = true;
+  return true;
+}
+
+static bool mg_aton6(struct mg_str str, struct mg_addr *addr) {
+  size_t i, j = 0, n = 0, dc = 42;
+  addr->scope_id = 0;
+  if (str.len > 2 && str.buf[0] == '[') str.buf++, str.len -= 2;
+  if (mg_v4mapped(str, addr)) return true;
+  for (i = 0; i < str.len; i++) {
+    if ((str.buf[i] >= '0' && str.buf[i] <= '9') ||
+        (str.buf[i] >= 'a' && str.buf[i] <= 'f') ||
+        (str.buf[i] >= 'A' && str.buf[i] <= 'F')) {
+      unsigned long val;  // TODO(): This loops on chars, refactor
+      if (i > j + 3) return false;
+      // MG_DEBUG(("%lu %lu [%.*s]", i, j, (int) (i - j + 1), &str.buf[j]));
+      mg_str_to_num(mg_str_n(&str.buf[j], i - j + 1), 16, &val, sizeof(val));
+      addr->ip[n] = (uint8_t) ((val >> 8) & 255);
+      addr->ip[n + 1] = (uint8_t) (val & 255);
+    } else if (str.buf[i] == ':') {
+      j = i + 1;
+      if (i > 0 && str.buf[i - 1] == ':') {
+        dc = n;  // Double colon
+        if (i > 1 && str.buf[i - 2] == ':') return false;
+      } else if (i > 0) {
+        n += 2;
+      }
+      if (n > 14) return false;
+      addr->ip[n] = addr->ip[n + 1] = 0;  // For trailing ::
+    } else if (str.buf[i] == '%') {       // Scope ID, last in string
+      return mg_str_to_num(mg_str_n(&str.buf[i + 1], str.len - i - 1), 10,
+                           &addr->scope_id, sizeof(uint8_t));
+    } else {
+      return false;
+    }
+  }
+  if (n < 14 && dc == 42) return false;
+  if (n < 14) {
+    memmove(&addr->ip[dc + (14 - n)], &addr->ip[dc], n - dc + 2);
+    memset(&addr->ip[dc], 0, 14 - n);
+  }
+
+  addr->is_ip6 = true;
+  return true;
+}
+
+bool mg_aton(struct mg_str str, struct mg_addr *addr) {
+  // MG_INFO(("[%.*s]", (int) str.len, str.buf));
+  return mg_atone(str, addr) || mg_atonl(str, addr) || mg_aton4(str, addr) ||
+         mg_aton6(str, addr);
+}
+
+struct mg_connection *mg_alloc_conn(struct mg_mgr *mgr) {
+  struct mg_connection *c =
+      (struct mg_connection *) calloc(1, sizeof(*c) + mgr->extraconnsize);
+  if (c != NULL) {
+    c->mgr = mgr;
+    c->send.align = c->recv.align = c->rtls.align = MG_IO_SIZE;
+    c->id = ++mgr->nextid;
+    MG_PROF_INIT(c);
+  }
+  return c;
+}
+
+void mg_close_conn(struct mg_connection *c) {
+  mg_resolve_cancel(c);  // Close any pending DNS query
+  LIST_DELETE(struct mg_connection, &c->mgr->conns, c);
+  if (c == c->mgr->dns4.c) c->mgr->dns4.c = NULL;
+  if (c == c->mgr->dns6.c) c->mgr->dns6.c = NULL;
+  // Order of operations is important. `MG_EV_CLOSE` event must be fired
+  // before we deallocate received data, see #1331
+  mg_call(c, MG_EV_CLOSE, NULL);
+  MG_DEBUG(("%lu %ld closed", c->id, c->fd));
+  MG_PROF_DUMP(c);
+  MG_PROF_FREE(c);
+
+  mg_tls_free(c);
+  mg_iobuf_free(&c->recv);
+  mg_iobuf_free(&c->send);
+  mg_iobuf_free(&c->rtls);
+  mg_bzero((unsigned char *) c, sizeof(*c));
+  free(c);
+}
+
+struct mg_connection *mg_connect(struct mg_mgr *mgr, const char *url,
+                                 mg_event_handler_t fn, void *fn_data) {
+  struct mg_connection *c = NULL;
+  if (url == NULL || url[0] == '\0') {
+    MG_ERROR(("null url"));
+  } else if ((c = mg_alloc_conn(mgr)) == NULL) {
+    MG_ERROR(("OOM"));
+  } else {
+    LIST_ADD_HEAD(struct mg_connection, &mgr->conns, c);
+    c->is_udp = (strncmp(url, "udp:", 4) == 0);
+    c->fd = (void *) (size_t) MG_INVALID_SOCKET;
+    c->fn = fn;
+    c->is_client = true;
+    c->fn_data = fn_data;
+    MG_DEBUG(("%lu %ld %s", c->id, c->fd, url));
+    mg_call(c, MG_EV_OPEN, (void *) url);
+    mg_resolve(c, url);
+  }
+  return c;
+}
+
+struct mg_connection *mg_listen(struct mg_mgr *mgr, const char *url,
+                                mg_event_handler_t fn, void *fn_data) {
+  struct mg_connection *c = NULL;
+  if ((c = mg_alloc_conn(mgr)) == NULL) {
+    MG_ERROR(("OOM %s", url));
+  } else if (!mg_open_listener(c, url)) {
+    MG_ERROR(("Failed: %s, errno %d", url, errno));
+    MG_PROF_FREE(c);
+    free(c);
+    c = NULL;
+  } else {
+    c->is_listening = 1;
+    c->is_udp = strncmp(url, "udp:", 4) == 0;
+    LIST_ADD_HEAD(struct mg_connection, &mgr->conns, c);
+    c->fn = fn;
+    c->fn_data = fn_data;
+    mg_call(c, MG_EV_OPEN, NULL);
+    if (mg_url_is_ssl(url)) c->is_tls = 1;  // Accepted connection must
+    MG_DEBUG(("%lu %ld %s", c->id, c->fd, url));
+  }
+  return c;
+}
+
+struct mg_connection *mg_wrapfd(struct mg_mgr *mgr, int fd,
+                                mg_event_handler_t fn, void *fn_data) {
+  struct mg_connection *c = mg_alloc_conn(mgr);
+  if (c != NULL) {
+    c->fd = (void *) (size_t) fd;
+    c->fn = fn;
+    c->fn_data = fn_data;
+    MG_EPOLL_ADD(c);
+    mg_call(c, MG_EV_OPEN, NULL);
+    LIST_ADD_HEAD(struct mg_connection, &mgr->conns, c);
+  }
+  return c;
+}
+
+struct mg_timer *mg_timer_add(struct mg_mgr *mgr, uint64_t milliseconds,
+                              unsigned flags, void (*fn)(void *), void *arg) {
+  struct mg_timer *t = (struct mg_timer *) calloc(1, sizeof(*t));
+  if (t != NULL) {
+    mg_timer_init(&mgr->timers, t, milliseconds, flags, fn, arg);
+    t->id = mgr->timerid++;
+  }
+  return t;
+}
+
+long mg_io_recv(struct mg_connection *c, void *buf, size_t len) {
+  if (c->rtls.len == 0) return MG_IO_WAIT;
+  if (len > c->rtls.len) len = c->rtls.len;
+  memcpy(buf, c->rtls.buf, len);
+  mg_iobuf_del(&c->rtls, 0, len);
+  return (long) len;
+}
+
+void mg_mgr_free(struct mg_mgr *mgr) {
+  struct mg_connection *c;
+  struct mg_timer *tmp, *t = mgr->timers;
+  while (t != NULL) tmp = t->next, free(t), t = tmp;
+  mgr->timers = NULL;  // Important. Next call to poll won't touch timers
+  for (c = mgr->conns; c != NULL; c = c->next) c->is_closing = 1;
+  mg_mgr_poll(mgr, 0);
+#if MG_ENABLE_FREERTOS_TCP
+  FreeRTOS_DeleteSocketSet(mgr->ss);
+#endif
+  MG_DEBUG(("All connections closed"));
+#if MG_ENABLE_EPOLL
+  if (mgr->epoll_fd >= 0) close(mgr->epoll_fd), mgr->epoll_fd = -1;
+#endif
+  mg_tls_ctx_free(mgr);
+}
+
+void mg_mgr_init(struct mg_mgr *mgr) {
+  memset(mgr, 0, sizeof(*mgr));
+#if MG_ENABLE_EPOLL
+  if ((mgr->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0)
+    MG_ERROR(("epoll_create1 errno %d", errno));
+#else
+  mgr->epoll_fd = -1;
+#endif
+#if MG_ARCH == MG_ARCH_WIN32 && MG_ENABLE_WINSOCK
+  // clang-format off
+  { WSADATA data; WSAStartup(MAKEWORD(2, 2), &data); }
+  // clang-format on
+#elif MG_ENABLE_FREERTOS_TCP
+  mgr->ss = FreeRTOS_CreateSocketSet();
+#elif defined(__unix) || defined(__unix__) || defined(__APPLE__)
+  // Ignore SIGPIPE signal, so if client cancels the request, it
+  // won't kill the whole process.
+  signal(SIGPIPE, SIG_IGN);
+#elif MG_ENABLE_TCPIP_DRIVER_INIT && defined(MG_TCPIP_DRIVER_INIT)
+  MG_TCPIP_DRIVER_INIT(mgr);
+#endif
+  mgr->pipe = MG_INVALID_SOCKET;
+  mgr->dnstimeout = 3000;
+  mgr->dns4.url = "udp://8.8.8.8:53";
+  mgr->dns6.url = "udp://[2001:4860:4860::8888]:53";
+  mg_tls_ctx_init(mgr);
+}
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/net_builtin.c"
+#endif
+
+
+#if defined(MG_ENABLE_TCPIP) && MG_ENABLE_TCPIP
+#define MG_EPHEMERAL_PORT_BASE 32768
+#define PDIFF(a, b) ((size_t) (((char *) (b)) - ((char *) (a))))
+
+#ifndef MIP_TCP_KEEPALIVE_MS
+#define MIP_TCP_KEEPALIVE_MS 45000  // TCP keep-alive period, ms
+#endif
+
+#define MIP_TCP_ACK_MS 150    // Timeout for ACKing
+#define MIP_TCP_ARP_MS 100    // Timeout for ARP response
+#define MIP_TCP_SYN_MS 15000  // Timeout for connection establishment
+#define MIP_TCP_FIN_MS 1000   // Timeout for closing connection
+#define MIP_TCP_WIN 6000      // TCP window size
+
+struct connstate {
+  uint32_t seq, ack;           // TCP seq/ack counters
+  uint64_t timer;              // TCP keep-alive / ACK timer
+  uint32_t acked;              // Last ACK-ed number
+  size_t unacked;              // Not acked bytes
+  uint8_t mac[6];              // Peer MAC address
+  uint8_t ttype;               // Timer type. 0: ack, 1: keep-alive
+#define MIP_TTYPE_KEEPALIVE 0  // Connection is idle for long, send keepalive
+#define MIP_TTYPE_ACK 1        // Peer sent us data, we have to ack it soon
+#define MIP_TTYPE_ARP 2        // ARP resolve sent, waiting for response
+#define MIP_TTYPE_SYN 3        // SYN sent, waiting for response
+#define MIP_TTYPE_FIN 4  // FIN sent, waiting until terminating the connection
+  uint8_t tmiss;         // Number of keep-alive misses
+  struct mg_iobuf raw;   // For TLS only. Incoming raw data
+};
+
+#pragma pack(push, 1)
+
+struct lcp {
+  uint8_t addr, ctrl, proto[2], code, id, len[2];
+};
+
+struct eth {
+  uint8_t dst[6];  // Destination MAC address
+  uint8_t src[6];  // Source MAC address
+  uint16_t type;   // Ethernet type
+};
+
+struct ip {
+  uint8_t ver;    // Version
+  uint8_t tos;    // Unused
+  uint16_t len;   // Length
+  uint16_t id;    // Unused
+  uint16_t frag;  // Fragmentation
+#define IP_FRAG_OFFSET_MSK 0xFF1F
+#define IP_MORE_FRAGS_MSK 0x20
+  uint8_t ttl;    // Time to live
+  uint8_t proto;  // Upper level protocol
+  uint16_t csum;  // Checksum
+  uint32_t src;   // Source IP
+  uint32_t dst;   // Destination IP
+};
+
+struct ip6 {
+  uint8_t ver;      // Version
+  uint8_t opts[3];  // Options
+  uint16_t len;     // Length
+  uint8_t proto;    // Upper level protocol
+  uint8_t ttl;      // Time to live
+  uint8_t src[16];  // Source IP
+  uint8_t dst[16];  // Destination IP
+};
+
+struct icmp {
+  uint8_t type;
+  uint8_t code;
+  uint16_t csum;
+};
+
+struct arp {
+  uint16_t fmt;    // Format of hardware address
+  uint16_t pro;    // Format of protocol address
+  uint8_t hlen;    // Length of hardware address
+  uint8_t plen;    // Length of protocol address
+  uint16_t op;     // Operation
+  uint8_t sha[6];  // Sender hardware address
+  uint32_t spa;    // Sender protocol address
+  uint8_t tha[6];  // Target hardware address
+  uint32_t tpa;    // Target protocol address
+};
+
+struct tcp {
+  uint16_t sport;  // Source port
+  uint16_t dport;  // Destination port
+  uint32_t seq;    // Sequence number
+  uint32_t ack;    // Acknowledgement number
+  uint8_t off;     // Data offset
+  uint8_t flags;   // TCP flags
+#define TH_FIN 0x01
+#define TH_SYN 0x02
+#define TH_RST 0x04
+#define TH_PUSH 0x08
+#define TH_ACK 0x10
+#define TH_URG 0x20
+#define TH_ECE 0x40
+#define TH_CWR 0x80
+  uint16_t win;   // Window
+  uint16_t csum;  // Checksum
+  uint16_t urp;   // Urgent pointer
+};
+
+struct udp {
+  uint16_t sport;  // Source port
+  uint16_t dport;  // Destination port
+  uint16_t len;    // UDP length
+  uint16_t csum;   // UDP checksum
+};
+
+struct dhcp {
+  uint8_t op, htype, hlen, hops;
+  uint32_t xid;
+  uint16_t secs, flags;
+  uint32_t ciaddr, yiaddr, siaddr, giaddr;
+  uint8_t hwaddr[208];
+  uint32_t magic;
+  uint8_t options[32];
+};
+
+#pragma pack(pop)
+
+struct pkt {
+  struct mg_str raw;  // Raw packet data
+  struct mg_str pay;  // Payload data
+  struct eth *eth;
+  struct llc *llc;
+  struct arp *arp;
+  struct ip *ip;
+  struct ip6 *ip6;
+  struct icmp *icmp;
+  struct tcp *tcp;
+  struct udp *udp;
+  struct dhcp *dhcp;
+};
+
+static void send_syn(struct mg_connection *c);
+
+static void mkpay(struct pkt *pkt, void *p) {
+  pkt->pay =
+      mg_str_n((char *) p, (size_t) (&pkt->raw.buf[pkt->raw.len] - (char *) p));
+}
+
+static uint32_t csumup(uint32_t sum, const void *buf, size_t len) {
+  size_t i;
+  const uint8_t *p = (const uint8_t *) buf;
+  for (i = 0; i < len; i++) sum += i & 1 ? p[i] : (uint32_t) (p[i] << 8);
+  return sum;
+}
+
+static uint16_t csumfin(uint32_t sum) {
+  while (sum >> 16) sum = (sum & 0xffff) + (sum >> 16);
+  return mg_htons(~sum & 0xffff);
+}
+
+static uint16_t ipcsum(const void *buf, size_t len) {
+  uint32_t sum = csumup(0, buf, len);
+  return csumfin(sum);
+}
+
+static void settmout(struct mg_connection *c, uint8_t type) {
+  struct mg_tcpip_if *ifp = (struct mg_tcpip_if *) c->mgr->priv;
+  struct connstate *s = (struct connstate *) (c + 1);
+  unsigned n = type == MIP_TTYPE_ACK   ? MIP_TCP_ACK_MS
+               : type == MIP_TTYPE_ARP ? MIP_TCP_ARP_MS
+               : type == MIP_TTYPE_SYN ? MIP_TCP_SYN_MS
+               : type == MIP_TTYPE_FIN ? MIP_TCP_FIN_MS
+                                       : MIP_TCP_KEEPALIVE_MS;
+  s->timer = ifp->now + n;
+  s->ttype = type;
+  MG_VERBOSE(("%lu %d -> %llx", c->id, type, s->timer));
+}
+
+static size_t ether_output(struct mg_tcpip_if *ifp, size_t len) {
+  size_t n = ifp->driver->tx(ifp->tx.buf, len, ifp);
+  if (n == len) ifp->nsent++;
+  return n;
+}
+
+static void arp_ask(struct mg_tcpip_if *ifp, uint32_t ip) {
+  struct eth *eth = (struct eth *) ifp->tx.buf;
+  struct arp *arp = (struct arp *) (eth + 1);
+  memset(eth->dst, 255, sizeof(eth->dst));
+  memcpy(eth->src, ifp->mac, sizeof(eth->src));
+  eth->type = mg_htons(0x806);
+  memset(arp, 0, sizeof(*arp));
+  arp->fmt = mg_htons(1), arp->pro = mg_htons(0x800), arp->hlen = 6,
+  arp->plen = 4;
+  arp->op = mg_htons(1), arp->tpa = ip, arp->spa = ifp->ip;
+  memcpy(arp->sha, ifp->mac, sizeof(arp->sha));
+  ether_output(ifp, PDIFF(eth, arp + 1));
+}
+
+static void onstatechange(struct mg_tcpip_if *ifp) {
+  if (ifp->state == MG_TCPIP_STATE_READY) {
+    MG_INFO(("READY, IP: %M", mg_print_ip4, &ifp->ip));
+    MG_INFO(("       GW: %M", mg_print_ip4, &ifp->gw));
+    MG_INFO(("      MAC: %M", mg_print_mac, &ifp->mac));
+    arp_ask(ifp, ifp->gw);
+  } else if (ifp->state == MG_TCPIP_STATE_UP) {
+    MG_ERROR(("Link up"));
+    srand((unsigned int) mg_millis());
+  } else if (ifp->state == MG_TCPIP_STATE_DOWN) {
+    MG_ERROR(("Link down"));
+  }
+}
+
+static struct ip *tx_ip(struct mg_tcpip_if *ifp, uint8_t *mac_dst,
+                        uint8_t proto, uint32_t ip_src, uint32_t ip_dst,
+                        size_t plen) {
+  struct eth *eth = (struct eth *) ifp->tx.buf;
+  struct ip *ip = (struct ip *) (eth + 1);
+  memcpy(eth->dst, mac_dst, sizeof(eth->dst));
+  memcpy(eth->src, ifp->mac, sizeof(eth->src));  // Use our MAC
+  eth->type = mg_htons(0x800);
+  memset(ip, 0, sizeof(*ip));
+  ip->ver = 0x45;   // Version 4, header length 5 words
+  ip->frag = 0x40;  // Don't fragment
+  ip->len = mg_htons((uint16_t) (sizeof(*ip) + plen));
+  ip->ttl = 64;
+  ip->proto = proto;
+  ip->src = ip_src;
+  ip->dst = ip_dst;
+  ip->csum = ipcsum(ip, sizeof(*ip));
+  return ip;
+}
+
+static void tx_udp(struct mg_tcpip_if *ifp, uint8_t *mac_dst, uint32_t ip_src,
+                   uint16_t sport, uint32_t ip_dst, uint16_t dport,
+                   const void *buf, size_t len) {
+  struct ip *ip =
+      tx_ip(ifp, mac_dst, 17, ip_src, ip_dst, len + sizeof(struct udp));
+  struct udp *udp = (struct udp *) (ip + 1);
+  // MG_DEBUG(("UDP XX LEN %d %d", (int) len, (int) ifp->tx.len));
+  udp->sport = sport;
+  udp->dport = dport;
+  udp->len = mg_htons((uint16_t) (sizeof(*udp) + len));
+  udp->csum = 0;
+  uint32_t cs = csumup(0, udp, sizeof(*udp));
+  cs = csumup(cs, buf, len);
+  cs = csumup(cs, &ip->src, sizeof(ip->src));
+  cs = csumup(cs, &ip->dst, sizeof(ip->dst));
+  cs += (uint32_t) (ip->proto + sizeof(*udp) + len);
+  udp->csum = csumfin(cs);
+  memmove(udp + 1, buf, len);
+  // MG_DEBUG(("UDP LEN %d %d", (int) len, (int) ifp->frame_len));
+  ether_output(ifp, sizeof(struct eth) + sizeof(*ip) + sizeof(*udp) + len);
+}
+
+static void tx_dhcp(struct mg_tcpip_if *ifp, uint8_t *mac_dst, uint32_t ip_src,
+                    uint32_t ip_dst, uint8_t *opts, size_t optslen,
+                    bool ciaddr) {
+  // https://datatracker.ietf.org/doc/html/rfc2132#section-9.6
+  struct dhcp dhcp = {1, 1, 6, 0, 0, 0, 0, 0, 0, 0, 0, {0}, 0, {0}};
+  dhcp.magic = mg_htonl(0x63825363);
+  memcpy(&dhcp.hwaddr, ifp->mac, sizeof(ifp->mac));
+  memcpy(&dhcp.xid, ifp->mac + 2, sizeof(dhcp.xid));
+  memcpy(&dhcp.options, opts, optslen);
+  if (ciaddr) dhcp.ciaddr = ip_src;
+  tx_udp(ifp, mac_dst, ip_src, mg_htons(68), ip_dst, mg_htons(67), &dhcp,
+         sizeof(dhcp));
+}
+
+static const uint8_t broadcast[] = {255, 255, 255, 255, 255, 255};
+
+// RFC-2131 #4.3.6, #4.4.1
+static void tx_dhcp_request_sel(struct mg_tcpip_if *ifp, uint32_t ip_req,
+                                uint32_t ip_srv) {
+  uint8_t opts[] = {
+      53, 1, 3,                 // Type: DHCP request
+      55, 2, 1,   3,            // GW and mask
+      12, 3, 'm', 'i', 'p',     // Host name: "mip"
+      54, 4, 0,   0,   0,   0,  // DHCP server ID
+      50, 4, 0,   0,   0,   0,  // Requested IP
+      255                       // End of options
+  };
+  memcpy(opts + 14, &ip_srv, sizeof(ip_srv));
+  memcpy(opts + 20, &ip_req, sizeof(ip_req));
+  tx_dhcp(ifp, (uint8_t *) broadcast, 0, 0xffffffff, opts, sizeof(opts), false);
+  MG_DEBUG(("DHCP req sent"));
+}
+
+// RFC-2131 #4.3.6, #4.4.5 (renewing: unicast, rebinding: bcast)
+static void tx_dhcp_request_re(struct mg_tcpip_if *ifp, uint8_t *mac_dst,
+                               uint32_t ip_src, uint32_t ip_dst) {
+  uint8_t opts[] = {
+      53, 1, 3,  // Type: DHCP request
+      255        // End of options
+  };
+  tx_dhcp(ifp, mac_dst, ip_src, ip_dst, opts, sizeof(opts), true);
+  MG_DEBUG(("DHCP req sent"));
+}
+
+static void tx_dhcp_discover(struct mg_tcpip_if *ifp) {
+  uint8_t opts[] = {
+      53, 1, 1,     // Type: DHCP discover
+      55, 2, 1, 3,  // Parameters: ip, mask
+      255           // End of options
+  };
+  tx_dhcp(ifp, (uint8_t *) broadcast, 0, 0xffffffff, opts, sizeof(opts), false);
+  MG_DEBUG(("DHCP discover sent. Our MAC: %M", mg_print_mac, ifp->mac));
+}
+
+static struct mg_connection *getpeer(struct mg_mgr *mgr, struct pkt *pkt,
+                                     bool lsn) {
+  struct mg_connection *c = NULL;
+  for (c = mgr->conns; c != NULL; c = c->next) {
+    if (c->is_arplooking && pkt->arp &&
+        memcmp(&pkt->arp->spa, c->rem.ip, sizeof(pkt->arp->spa)) == 0)
+      break;
+    if (c->is_udp && pkt->udp && c->loc.port == pkt->udp->dport) break;
+    if (!c->is_udp && pkt->tcp && c->loc.port == pkt->tcp->dport &&
+        lsn == c->is_listening && (lsn || c->rem.port == pkt->tcp->sport))
+      break;
+  }
+  return c;
+}
+
+static void rx_arp(struct mg_tcpip_if *ifp, struct pkt *pkt) {
+  if (pkt->arp->op == mg_htons(1) && pkt->arp->tpa == ifp->ip) {
+    // ARP request. Make a response, then send
+    // MG_DEBUG(("ARP op %d %M: %M", mg_ntohs(pkt->arp->op), mg_print_ip4,
+    //          &pkt->arp->spa, mg_print_ip4, &pkt->arp->tpa));
+    struct eth *eth = (struct eth *) ifp->tx.buf;
+    struct arp *arp = (struct arp *) (eth + 1);
+    memcpy(eth->dst, pkt->eth->src, sizeof(eth->dst));
+    memcpy(eth->src, ifp->mac, sizeof(eth->src));
+    eth->type = mg_htons(0x806);
+    *arp = *pkt->arp;
+    arp->op = mg_htons(2);
+    memcpy(arp->tha, pkt->arp->sha, sizeof(pkt->arp->tha));
+    memcpy(arp->sha, ifp->mac, sizeof(pkt->arp->sha));
+    arp->tpa = pkt->arp->spa;
+    arp->spa = ifp->ip;
+    MG_DEBUG(("ARP: tell %M we're %M", mg_print_ip4, &arp->tpa, mg_print_mac,
+              &ifp->mac));
+    ether_output(ifp, PDIFF(eth, arp + 1));
+  } else if (pkt->arp->op == mg_htons(2)) {
+    if (memcmp(pkt->arp->tha, ifp->mac, sizeof(pkt->arp->tha)) != 0) return;
+    if (pkt->arp->spa == ifp->gw) {
+      // Got response for the GW ARP request. Set ifp->gwmac
+      memcpy(ifp->gwmac, pkt->arp->sha, sizeof(ifp->gwmac));
+    } else {
+      struct mg_connection *c = getpeer(ifp->mgr, pkt, false);
+      if (c != NULL && c->is_arplooking) {
+        struct connstate *s = (struct connstate *) (c + 1);
+        memcpy(s->mac, pkt->arp->sha, sizeof(s->mac));
+        MG_DEBUG(("%lu ARP resolved %M -> %M", c->id, mg_print_ip4, c->rem.ip,
+                  mg_print_mac, s->mac));
+        c->is_arplooking = 0;
+        send_syn(c);
+        settmout(c, MIP_TTYPE_SYN);
+      }
+    }
+  }
+}
+
+static void rx_icmp(struct mg_tcpip_if *ifp, struct pkt *pkt) {
+  // MG_DEBUG(("ICMP %d", (int) len));
+  if (pkt->icmp->type == 8 && pkt->ip != NULL && pkt->ip->dst == ifp->ip) {
+    size_t hlen = sizeof(struct eth) + sizeof(struct ip) + sizeof(struct icmp);
+    size_t space = ifp->tx.len - hlen, plen = pkt->pay.len;
+    if (plen > space) plen = space;
+    struct ip *ip = tx_ip(ifp, pkt->eth->src, 1, ifp->ip, pkt->ip->src,
+                          sizeof(struct icmp) + plen);
+    struct icmp *icmp = (struct icmp *) (ip + 1);
+    memset(icmp, 0, sizeof(*icmp));        // Set csum to 0
+    memcpy(icmp + 1, pkt->pay.buf, plen);  // Copy RX payload to TX
+    icmp->csum = ipcsum(icmp, sizeof(*icmp) + plen);
+    ether_output(ifp, hlen + plen);
+  }
+}
+
+static void rx_dhcp_client(struct mg_tcpip_if *ifp, struct pkt *pkt) {
+  uint32_t ip = 0, gw = 0, mask = 0, lease = 0;
+  uint8_t msgtype = 0, state = ifp->state;
+  // perform size check first, then access fields
+  uint8_t *p = pkt->dhcp->options,
+          *end = (uint8_t *) &pkt->raw.buf[pkt->raw.len];
+  if (end < (uint8_t *) (pkt->dhcp + 1)) return;
+  if (memcmp(&pkt->dhcp->xid, ifp->mac + 2, sizeof(pkt->dhcp->xid))) return;
+  while (p + 1 < end && p[0] != 255) {  // Parse options RFC-1533 #9
+    if (p[0] == 1 && p[1] == sizeof(ifp->mask) && p + 6 < end) {  // Mask
+      memcpy(&mask, p + 2, sizeof(mask));
+    } else if (p[0] == 3 && p[1] == sizeof(ifp->gw) && p + 6 < end) {  // GW
+      memcpy(&gw, p + 2, sizeof(gw));
+      ip = pkt->dhcp->yiaddr;
+    } else if (p[0] == 51 && p[1] == 4 && p + 6 < end) {  // Lease
+      memcpy(&lease, p + 2, sizeof(lease));
+      lease = mg_ntohl(lease);
+    } else if (p[0] == 53 && p[1] == 1 && p + 6 < end) {  // Msg Type
+      msgtype = p[2];
+    }
+    p += p[1] + 2;
+  }
+  // Process message type, RFC-1533 (9.4); RFC-2131 (3.1, 4)
+  if (msgtype == 6 && ifp->ip == ip) {  // DHCPNACK, release IP
+    ifp->state = MG_TCPIP_STATE_UP, ifp->ip = 0;
+  } else if (msgtype == 2 && ifp->state == MG_TCPIP_STATE_UP && ip && gw &&
+             lease) {  // DHCPOFFER
+    // select IP, (4.4.1) (fallback to IP source addr on foul play)
+    tx_dhcp_request_sel(ifp, ip,
+                        pkt->dhcp->siaddr ? pkt->dhcp->siaddr : pkt->ip->src);
+    ifp->state = MG_TCPIP_STATE_REQ;  // REQUESTING state
+  } else if (msgtype == 5) {          // DHCPACK
+    if (ifp->state == MG_TCPIP_STATE_REQ && ip && gw && lease) {  // got an IP
+      ifp->lease_expire = ifp->now + lease * 1000;
+      MG_INFO(("Lease: %u sec (%lld)", lease, ifp->lease_expire / 1000));
+      // assume DHCP server = router until ARP resolves
+      memcpy(ifp->gwmac, pkt->eth->src, sizeof(ifp->gwmac));
+      ifp->ip = ip, ifp->gw = gw, ifp->mask = mask;
+      ifp->state = MG_TCPIP_STATE_READY;  // BOUND state
+      uint64_t rand;
+      mg_random(&rand, sizeof(rand));
+      srand((unsigned int) (rand + mg_millis()));
+    } else if (ifp->state == MG_TCPIP_STATE_READY && ifp->ip == ip) {  // renew
+      ifp->lease_expire = ifp->now + lease * 1000;
+      MG_INFO(("Lease: %u sec (%lld)", lease, ifp->lease_expire / 1000));
+    }  // TODO(): accept provided T1/T2 and store server IP for renewal (4.4)
+  }
+  if (ifp->state != state) onstatechange(ifp);
+}
+
+// Simple DHCP server that assigns a next IP address: ifp->ip + 1
+static void rx_dhcp_server(struct mg_tcpip_if *ifp, struct pkt *pkt) {
+  uint8_t op = 0, *p = pkt->dhcp->options,
+          *end = (uint8_t *) &pkt->raw.buf[pkt->raw.len];
+  if (end < (uint8_t *) (pkt->dhcp + 1)) return;
+  // struct dhcp *req = pkt->dhcp;
+  struct dhcp res = {2, 1, 6, 0, 0, 0, 0, 0, 0, 0, 0, {0}, 0, {0}};
+  res.yiaddr = ifp->ip;
+  ((uint8_t *) (&res.yiaddr))[3]++;                // Offer our IP + 1
+  while (p + 1 < end && p[0] != 255) {             // Parse options
+    if (p[0] == 53 && p[1] == 1 && p + 2 < end) {  // Message type
+      op = p[2];
+    }
+    p += p[1] + 2;
+  }
+  if (op == 1 || op == 3) {         // DHCP Discover or DHCP Request
+    uint8_t msg = op == 1 ? 2 : 5;  // Message type: DHCP OFFER or DHCP ACK
+    uint8_t opts[] = {
+        53, 1, msg,                 // Message type
+        1,  4, 0,   0,   0,   0,    // Subnet mask
+        54, 4, 0,   0,   0,   0,    // Server ID
+        12, 3, 'm', 'i', 'p',       // Host name: "mip"
+        51, 4, 255, 255, 255, 255,  // Lease time
+        255                         // End of options
+    };
+    memcpy(&res.hwaddr, pkt->dhcp->hwaddr, 6);
+    memcpy(opts + 5, &ifp->mask, sizeof(ifp->mask));
+    memcpy(opts + 11, &ifp->ip, sizeof(ifp->ip));
+    memcpy(&res.options, opts, sizeof(opts));
+    res.magic = pkt->dhcp->magic;
+    res.xid = pkt->dhcp->xid;
+    if (ifp->enable_get_gateway) {
+      ifp->gw = res.yiaddr;
+      memcpy(ifp->gwmac, pkt->eth->src, sizeof(ifp->gwmac));
+    }
+    tx_udp(ifp, pkt->eth->src, ifp->ip, mg_htons(67),
+           op == 1 ? ~0U : res.yiaddr, mg_htons(68), &res, sizeof(res));
+  }
+}
+
+static void rx_udp(struct mg_tcpip_if *ifp, struct pkt *pkt) {
+  struct mg_connection *c = getpeer(ifp->mgr, pkt, true);
+  if (c == NULL) {
+    // No UDP listener on this port. Should send ICMP, but keep silent.
+  } else {
+    c->rem.port = pkt->udp->sport;
+    memcpy(c->rem.ip, &pkt->ip->src, sizeof(uint32_t));
+    struct connstate *s = (struct connstate *) (c + 1);
+    memcpy(s->mac, pkt->eth->src, sizeof(s->mac));
+    if (c->recv.len >= MG_MAX_RECV_SIZE) {
+      mg_error(c, "max_recv_buf_size reached");
+    } else if (c->recv.size - c->recv.len < pkt->pay.len &&
+               !mg_iobuf_resize(&c->recv, c->recv.len + pkt->pay.len)) {
+      mg_error(c, "oom");
+    } else {
+      memcpy(&c->recv.buf[c->recv.len], pkt->pay.buf, pkt->pay.len);
+      c->recv.len += pkt->pay.len;
+      mg_call(c, MG_EV_READ, &pkt->pay.len);
+    }
+  }
+}
+
+static size_t tx_tcp(struct mg_tcpip_if *ifp, uint8_t *dst_mac, uint32_t dst_ip,
+                     uint8_t flags, uint16_t sport, uint16_t dport,
+                     uint32_t seq, uint32_t ack, const void *buf, size_t len) {
+#if 0
+  uint8_t opts[] = {2, 4, 5, 0xb4, 4, 2, 0, 0};  // MSS = 1460, SACK permitted
+  if (flags & TH_SYN) {
+    // Handshake? Set MSS
+    buf = opts;
+    len = sizeof(opts);
+  }
+#endif
+  struct ip *ip =
+      tx_ip(ifp, dst_mac, 6, ifp->ip, dst_ip, sizeof(struct tcp) + len);
+  struct tcp *tcp = (struct tcp *) (ip + 1);
+  memset(tcp, 0, sizeof(*tcp));
+  if (buf != NULL && len) memmove(tcp + 1, buf, len);
+  tcp->sport = sport;
+  tcp->dport = dport;
+  tcp->seq = seq;
+  tcp->ack = ack;
+  tcp->flags = flags;
+  tcp->win = mg_htons(MIP_TCP_WIN);
+  tcp->off = (uint8_t) (sizeof(*tcp) / 4 << 4);
+  // if (flags & TH_SYN) tcp->off = 0x70;  // Handshake? header size 28 bytes
+
+  uint32_t cs = 0;
+  uint16_t n = (uint16_t) (sizeof(*tcp) + len);
+  uint8_t pseudo[] = {0, ip->proto, (uint8_t) (n >> 8), (uint8_t) (n & 255)};
+  cs = csumup(cs, tcp, n);
+  cs = csumup(cs, &ip->src, sizeof(ip->src));
+  cs = csumup(cs, &ip->dst, sizeof(ip->dst));
+  cs = csumup(cs, pseudo, sizeof(pseudo));
+  tcp->csum = csumfin(cs);
+  MG_VERBOSE(("TCP %M:%hu -> %M:%hu fl %x len %u", mg_print_ip4, &ip->src,
+              mg_ntohs(tcp->sport), mg_print_ip4, &ip->dst,
+              mg_ntohs(tcp->dport), tcp->flags, len));
+  // mg_hexdump(ifp->tx.buf, PDIFF(ifp->tx.buf, tcp + 1) + len);
+  return ether_output(ifp, PDIFF(ifp->tx.buf, tcp + 1) + len);
+}
+
+static size_t tx_tcp_pkt(struct mg_tcpip_if *ifp, struct pkt *pkt,
+                         uint8_t flags, uint32_t seq, const void *buf,
+                         size_t len) {
+  uint32_t delta = (pkt->tcp->flags & (TH_SYN | TH_FIN)) ? 1 : 0;
+  return tx_tcp(ifp, pkt->eth->src, pkt->ip->src, flags, pkt->tcp->dport,
+                pkt->tcp->sport, seq, mg_htonl(mg_ntohl(pkt->tcp->seq) + delta),
+                buf, len);
+}
+
+static struct mg_connection *accept_conn(struct mg_connection *lsn,
+                                         struct pkt *pkt) {
+  struct mg_connection *c = mg_alloc_conn(lsn->mgr);
+  if (c == NULL) {
+    MG_ERROR(("OOM"));
+    return NULL;
+  }
+  struct connstate *s = (struct connstate *) (c + 1);
+  s->seq = mg_ntohl(pkt->tcp->ack), s->ack = mg_ntohl(pkt->tcp->seq);
+  memcpy(s->mac, pkt->eth->src, sizeof(s->mac));
+  settmout(c, MIP_TTYPE_KEEPALIVE);
+  memcpy(c->rem.ip, &pkt->ip->src, sizeof(uint32_t));
+  c->rem.port = pkt->tcp->sport;
+  MG_DEBUG(("%lu accepted %M", c->id, mg_print_ip_port, &c->rem));
+  LIST_ADD_HEAD(struct mg_connection, &lsn->mgr->conns, c);
+  c->is_accepted = 1;
+  c->is_hexdumping = lsn->is_hexdumping;
+  c->pfn = lsn->pfn;
+  c->loc = lsn->loc;
+  c->pfn_data = lsn->pfn_data;
+  c->fn = lsn->fn;
+  c->fn_data = lsn->fn_data;
+  mg_call(c, MG_EV_OPEN, NULL);
+  mg_call(c, MG_EV_ACCEPT, NULL);
+  return c;
+}
+
+static size_t trim_len(struct mg_connection *c, size_t len) {
+  struct mg_tcpip_if *ifp = (struct mg_tcpip_if *) c->mgr->priv;
+  size_t eth_h_len = 14, ip_max_h_len = 24, tcp_max_h_len = 60, udp_h_len = 8;
+  size_t max_headers_len =
+      eth_h_len + ip_max_h_len + (c->is_udp ? udp_h_len : tcp_max_h_len);
+  size_t min_mtu = c->is_udp ? 68 /* RFC-791 */ : max_headers_len - eth_h_len;
+
+  // If the frame exceeds the available buffer, trim the length
+  if (len + max_headers_len > ifp->tx.len) {
+    len = ifp->tx.len - max_headers_len;
+  }
+  // Ensure the MTU isn't lower than the minimum allowed value
+  if (ifp->mtu < min_mtu) {
+    MG_ERROR(("MTU is lower than minimum, capping to %lu", min_mtu));
+    ifp->mtu = (uint16_t) min_mtu;
+  }
+  // If the total packet size exceeds the MTU, trim the length
+  if (len + max_headers_len - eth_h_len > ifp->mtu) {
+    len = ifp->mtu - max_headers_len + eth_h_len;
+    if (c->is_udp) {
+      MG_ERROR(("UDP datagram exceeds MTU. Truncating it."));
+    }
+  }
+
+  return len;
+}
+
+long mg_io_send(struct mg_connection *c, const void *buf, size_t len) {
+  struct mg_tcpip_if *ifp = (struct mg_tcpip_if *) c->mgr->priv;
+  struct connstate *s = (struct connstate *) (c + 1);
+  uint32_t dst_ip = *(uint32_t *) c->rem.ip;
+  len = trim_len(c, len);
+  if (c->is_udp) {
+    tx_udp(ifp, s->mac, ifp->ip, c->loc.port, dst_ip, c->rem.port, buf, len);
+  } else {
+    size_t sent =
+        tx_tcp(ifp, s->mac, dst_ip, TH_PUSH | TH_ACK, c->loc.port, c->rem.port,
+               mg_htonl(s->seq), mg_htonl(s->ack), buf, len);
+    if (sent == 0) {
+      return MG_IO_WAIT;
+    } else if (sent == (size_t) -1) {
+      return MG_IO_ERR;
+    } else {
+      s->seq += (uint32_t) len;
+      if (s->ttype == MIP_TTYPE_ACK) settmout(c, MIP_TTYPE_KEEPALIVE);
+    }
+  }
+  return (long) len;
+}
+
+static void handle_tls_recv(struct mg_connection *c, struct mg_iobuf *io) {
+  long n = mg_tls_recv(c, &io->buf[io->len], io->size - io->len);
+  if (n == MG_IO_ERR) {
+    mg_error(c, "TLS recv error");
+  } else if (n > 0) {
+    // Decrypted successfully - trigger MG_EV_READ
+    io->len += (size_t) n;
+    mg_call(c, MG_EV_READ, &n);
+  }
+}
+
+static void read_conn(struct mg_connection *c, struct pkt *pkt) {
+  struct connstate *s = (struct connstate *) (c + 1);
+  struct mg_iobuf *io = c->is_tls ? &c->rtls : &c->recv;
+  uint32_t seq = mg_ntohl(pkt->tcp->seq);
+  uint32_t rem_ip;
+  memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t));
+  if (pkt->tcp->flags & TH_FIN) {
+    // If we initiated the closure, we reply with ACK upon receiving FIN
+    // If we didn't initiate it, we reply with FIN as part of the normal TCP
+    // closure process
+    uint8_t flags = TH_ACK;
+    s->ack = (uint32_t) (mg_htonl(pkt->tcp->seq) + pkt->pay.len + 1);
+    if (c->is_draining && s->ttype == MIP_TTYPE_FIN) {
+      if (s->seq == mg_htonl(pkt->tcp->ack)) {  // Simultaneous closure ?
+        s->seq++;                               // Yes. Increment our SEQ
+      } else {                                  // Otherwise,
+        s->seq = mg_htonl(pkt->tcp->ack);       // Set to peer's ACK
+      }
+    } else {
+      flags |= TH_FIN;
+      c->is_draining = 1;
+      settmout(c, MIP_TTYPE_FIN);
+    }
+    tx_tcp((struct mg_tcpip_if *) c->mgr->priv, s->mac, rem_ip, flags,
+           c->loc.port, c->rem.port, mg_htonl(s->seq), mg_htonl(s->ack), "", 0);
+  } else if (pkt->pay.len == 0) {
+    // TODO(cpq): handle this peer's ACK
+  } else if (seq != s->ack) {
+    uint32_t ack = (uint32_t) (mg_htonl(pkt->tcp->seq) + pkt->pay.len);
+    if (s->ack == ack) {
+      MG_VERBOSE(("ignoring duplicate pkt"));
+    } else {
+      MG_VERBOSE(("SEQ != ACK: %x %x %x", seq, s->ack, ack));
+      tx_tcp((struct mg_tcpip_if *) c->mgr->priv, s->mac, rem_ip, TH_ACK,
+             c->loc.port, c->rem.port, mg_htonl(s->seq), mg_htonl(s->ack), "",
+             0);
+    }
+  } else if (io->size - io->len < pkt->pay.len &&
+             !mg_iobuf_resize(io, io->len + pkt->pay.len)) {
+    mg_error(c, "oom");
+  } else {
+    // Copy TCP payload into the IO buffer. If the connection is plain text,
+    // we copy to c->recv. If the connection is TLS, this data is encrypted,
+    // therefore we copy that encrypted data to the c->rtls iobuffer instead,
+    // and then call mg_tls_recv() to decrypt it. NOTE: mg_tls_recv() will
+    // call back mg_io_recv() which grabs raw data from c->rtls
+    memcpy(&io->buf[io->len], pkt->pay.buf, pkt->pay.len);
+    io->len += pkt->pay.len;
+
+    MG_VERBOSE(("%lu SEQ %x -> %x", c->id, mg_htonl(pkt->tcp->seq), s->ack));
+    // Advance ACK counter
+    s->ack = (uint32_t) (mg_htonl(pkt->tcp->seq) + pkt->pay.len);
+    s->unacked += pkt->pay.len;
+    // size_t diff = s->acked <= s->ack ? s->ack - s->acked : s->ack;
+    if (s->unacked > MIP_TCP_WIN / 2 && s->acked != s->ack) {
+      // Send ACK immediately
+      MG_VERBOSE(("%lu imm ACK %lu", c->id, s->acked));
+      tx_tcp((struct mg_tcpip_if *) c->mgr->priv, s->mac, rem_ip, TH_ACK,
+             c->loc.port, c->rem.port, mg_htonl(s->seq), mg_htonl(s->ack), NULL,
+             0);
+      s->unacked = 0;
+      s->acked = s->ack;
+      if (s->ttype != MIP_TTYPE_KEEPALIVE) settmout(c, MIP_TTYPE_KEEPALIVE);
+    } else {
+      // if not already running, setup a timer to send an ACK later
+      if (s->ttype != MIP_TTYPE_ACK) settmout(c, MIP_TTYPE_ACK);
+    }
+
+    if (c->is_tls && c->is_tls_hs) {
+      mg_tls_handshake(c);
+    } else if (c->is_tls) {
+      // TLS connection. Make room for decrypted data in c->recv
+      io = &c->recv;
+      if (io->size - io->len < pkt->pay.len &&
+          !mg_iobuf_resize(io, io->len + pkt->pay.len)) {
+        mg_error(c, "oom");
+      } else {
+        // Decrypt data directly into c->recv
+        handle_tls_recv(c, io);
+      }
+    } else {
+      // Plain text connection, data is already in c->recv, trigger
+      // MG_EV_READ
+      mg_call(c, MG_EV_READ, &pkt->pay.len);
+    }
+  }
+}
+
+static void rx_tcp(struct mg_tcpip_if *ifp, struct pkt *pkt) {
+  struct mg_connection *c = getpeer(ifp->mgr, pkt, false);
+  struct connstate *s = c == NULL ? NULL : (struct connstate *) (c + 1);
+#if 0
+  MG_INFO(("%lu %hhu %d", c ? c->id : 0, pkt->tcp->flags, (int) pkt->pay.len));
+#endif
+  if (c != NULL && c->is_connecting && pkt->tcp->flags == (TH_SYN | TH_ACK)) {
+    s->seq = mg_ntohl(pkt->tcp->ack), s->ack = mg_ntohl(pkt->tcp->seq) + 1;
+    tx_tcp_pkt(ifp, pkt, TH_ACK, pkt->tcp->ack, NULL, 0);
+    c->is_connecting = 0;  // Client connected
+    settmout(c, MIP_TTYPE_KEEPALIVE);
+    mg_call(c, MG_EV_CONNECT, NULL);  // Let user know
+  } else if (c != NULL && c->is_connecting && pkt->tcp->flags != TH_ACK) {
+    // mg_hexdump(pkt->raw.buf, pkt->raw.len);
+    tx_tcp_pkt(ifp, pkt, TH_RST | TH_ACK, pkt->tcp->ack, NULL, 0);
+  } else if (c != NULL && pkt->tcp->flags & TH_RST) {
+    mg_error(c, "peer RST");  // RFC-1122 4.2.2.13
+  } else if (c != NULL) {
+#if 0
+    MG_DEBUG(("%lu %d %M:%hu -> %M:%hu", c->id, (int) pkt->raw.len,
+              mg_print_ip4, &pkt->ip->src, mg_ntohs(pkt->tcp->sport),
+              mg_print_ip4, &pkt->ip->dst, mg_ntohs(pkt->tcp->dport)));
+    mg_hexdump(pkt->pay.buf, pkt->pay.len);
+#endif
+    s->tmiss = 0;                         // Reset missed keep-alive counter
+    if (s->ttype == MIP_TTYPE_KEEPALIVE)  // Advance keep-alive timer
+      settmout(c,
+               MIP_TTYPE_KEEPALIVE);  // unless a former ACK timeout is pending
+    read_conn(c, pkt);  // Override timer with ACK timeout if needed
+  } else if ((c = getpeer(ifp->mgr, pkt, true)) == NULL) {
+    tx_tcp_pkt(ifp, pkt, TH_RST | TH_ACK, pkt->tcp->ack, NULL, 0);
+  } else if (pkt->tcp->flags & TH_RST) {
+    if (c->is_accepted) mg_error(c, "peer RST");  // RFC-1122 4.2.2.13
+    // ignore RST if not connected
+  } else if (pkt->tcp->flags & TH_SYN) {
+    // Use peer's source port as ISN, in order to recognise the handshake
+    uint32_t isn = mg_htonl((uint32_t) mg_ntohs(pkt->tcp->sport));
+    tx_tcp_pkt(ifp, pkt, TH_SYN | TH_ACK, isn, NULL, 0);
+  } else if (pkt->tcp->flags & TH_FIN) {
+    tx_tcp_pkt(ifp, pkt, TH_FIN | TH_ACK, pkt->tcp->ack, NULL, 0);
+  } else if (mg_htonl(pkt->tcp->ack) == mg_htons(pkt->tcp->sport) + 1U) {
+    accept_conn(c, pkt);
+  } else if (!c->is_accepted) {  // no peer
+    tx_tcp_pkt(ifp, pkt, TH_RST | TH_ACK, pkt->tcp->ack, NULL, 0);
+  } else {
+    // MG_VERBOSE(("dropped silently.."));
+  }
+}
+
+static void rx_ip(struct mg_tcpip_if *ifp, struct pkt *pkt) {
+  if (pkt->ip->frag & IP_MORE_FRAGS_MSK || pkt->ip->frag & IP_FRAG_OFFSET_MSK) {
+    if (pkt->ip->proto == 17) pkt->udp = (struct udp *) (pkt->ip + 1);
+    if (pkt->ip->proto == 6) pkt->tcp = (struct tcp *) (pkt->ip + 1);
+    struct mg_connection *c = getpeer(ifp->mgr, pkt, false);
+    if (c) mg_error(c, "Received fragmented packet");
+  } else if (pkt->ip->proto == 1) {
+    pkt->icmp = (struct icmp *) (pkt->ip + 1);
+    if (pkt->pay.len < sizeof(*pkt->icmp)) return;
+    mkpay(pkt, pkt->icmp + 1);
+    rx_icmp(ifp, pkt);
+  } else if (pkt->ip->proto == 17) {
+    pkt->udp = (struct udp *) (pkt->ip + 1);
+    if (pkt->pay.len < sizeof(*pkt->udp)) return;
+    mkpay(pkt, pkt->udp + 1);
+    MG_VERBOSE(("UDP %M:%hu -> %M:%hu len %u", mg_print_ip4, &pkt->ip->src,
+                mg_ntohs(pkt->udp->sport), mg_print_ip4, &pkt->ip->dst,
+                mg_ntohs(pkt->udp->dport), (int) pkt->pay.len));
+    if (ifp->enable_dhcp_client && pkt->udp->dport == mg_htons(68)) {
+      pkt->dhcp = (struct dhcp *) (pkt->udp + 1);
+      mkpay(pkt, pkt->dhcp + 1);
+      rx_dhcp_client(ifp, pkt);
+    } else if (ifp->enable_dhcp_server && pkt->udp->dport == mg_htons(67)) {
+      pkt->dhcp = (struct dhcp *) (pkt->udp + 1);
+      mkpay(pkt, pkt->dhcp + 1);
+      rx_dhcp_server(ifp, pkt);
+    } else {
+      rx_udp(ifp, pkt);
+    }
+  } else if (pkt->ip->proto == 6) {
+    pkt->tcp = (struct tcp *) (pkt->ip + 1);
+    if (pkt->pay.len < sizeof(*pkt->tcp)) return;
+    mkpay(pkt, pkt->tcp + 1);
+    uint16_t iplen = mg_ntohs(pkt->ip->len);
+    uint16_t off = (uint16_t) (sizeof(*pkt->ip) + ((pkt->tcp->off >> 4) * 4U));
+    if (iplen >= off) pkt->pay.len = (size_t) (iplen - off);
+    MG_VERBOSE(("TCP %M:%hu -> %M:%hu len %u", mg_print_ip4, &pkt->ip->src,
+                mg_ntohs(pkt->tcp->sport), mg_print_ip4, &pkt->ip->dst,
+                mg_ntohs(pkt->tcp->dport), (int) pkt->pay.len));
+    rx_tcp(ifp, pkt);
+  }
+}
+
+static void rx_ip6(struct mg_tcpip_if *ifp, struct pkt *pkt) {
+  // MG_DEBUG(("IP %d", (int) len));
+  if (pkt->ip6->proto == 1 || pkt->ip6->proto == 58) {
+    pkt->icmp = (struct icmp *) (pkt->ip6 + 1);
+    if (pkt->pay.len < sizeof(*pkt->icmp)) return;
+    mkpay(pkt, pkt->icmp + 1);
+    rx_icmp(ifp, pkt);
+  } else if (pkt->ip6->proto == 17) {
+    pkt->udp = (struct udp *) (pkt->ip6 + 1);
+    if (pkt->pay.len < sizeof(*pkt->udp)) return;
+    // MG_DEBUG(("  UDP %u %u -> %u", len, mg_htons(udp->sport),
+    // mg_htons(udp->dport)));
+    mkpay(pkt, pkt->udp + 1);
+  }
+}
+
+static void mg_tcpip_rx(struct mg_tcpip_if *ifp, void *buf, size_t len) {
+  struct pkt pkt;
+  memset(&pkt, 0, sizeof(pkt));
+  pkt.raw.buf = (char *) buf;
+  pkt.raw.len = len;
+  pkt.eth = (struct eth *) buf;
+  // mg_hexdump(buf, len > 16 ? 16: len);
+  if (pkt.raw.len < sizeof(*pkt.eth)) return;  // Truncated - runt?
+  if (ifp->enable_mac_check &&
+      memcmp(pkt.eth->dst, ifp->mac, sizeof(pkt.eth->dst)) != 0 &&
+      memcmp(pkt.eth->dst, broadcast, sizeof(pkt.eth->dst)) != 0)
+    return;
+  if (ifp->enable_crc32_check && len > 4) {
+    len -= 4;  // TODO(scaprile): check on bigendian
+    uint32_t crc = mg_crc32(0, (const char *) buf, len);
+    if (memcmp((void *) ((size_t) buf + len), &crc, sizeof(crc))) return;
+  }
+  if (pkt.eth->type == mg_htons(0x806)) {
+    pkt.arp = (struct arp *) (pkt.eth + 1);
+    if (sizeof(*pkt.eth) + sizeof(*pkt.arp) > pkt.raw.len) return;  // Truncated
+    rx_arp(ifp, &pkt);
+  } else if (pkt.eth->type == mg_htons(0x86dd)) {
+    pkt.ip6 = (struct ip6 *) (pkt.eth + 1);
+    if (pkt.raw.len < sizeof(*pkt.eth) + sizeof(*pkt.ip6)) return;  // Truncated
+    if ((pkt.ip6->ver >> 4) != 0x6) return;                         // Not IP
+    mkpay(&pkt, pkt.ip6 + 1);
+    rx_ip6(ifp, &pkt);
+  } else if (pkt.eth->type == mg_htons(0x800)) {
+    pkt.ip = (struct ip *) (pkt.eth + 1);
+    if (pkt.raw.len < sizeof(*pkt.eth) + sizeof(*pkt.ip)) return;  // Truncated
+    // Truncate frame to what IP header tells us
+    if ((size_t) mg_ntohs(pkt.ip->len) + sizeof(struct eth) < pkt.raw.len) {
+      pkt.raw.len = (size_t) mg_ntohs(pkt.ip->len) + sizeof(struct eth);
+    }
+    if (pkt.raw.len < sizeof(*pkt.eth) + sizeof(*pkt.ip)) return;  // Truncated
+    if ((pkt.ip->ver >> 4) != 4) return;                           // Not IP
+    mkpay(&pkt, pkt.ip + 1);
+    rx_ip(ifp, &pkt);
+  } else {
+    MG_DEBUG(("Unknown eth type %x", mg_htons(pkt.eth->type)));
+    if (mg_log_level >= MG_LL_VERBOSE) mg_hexdump(buf, len >= 32 ? 32 : len);
+  }
+}
+
+static void mg_tcpip_poll(struct mg_tcpip_if *ifp, uint64_t now) {
+  struct mg_connection *c;
+  bool expired_1000ms = mg_timer_expired(&ifp->timer_1000ms, 1000, now);
+  ifp->now = now;
+
+#if MG_ENABLE_TCPIP_PRINT_DEBUG_STATS
+  if (expired_1000ms) {
+    const char *names[] = {"down", "up", "req", "ready"};
+    MG_INFO(("Status: %s, IP: %M, rx:%u, tx:%u, dr:%u, er:%u",
+             names[ifp->state], mg_print_ip4, &ifp->ip, ifp->nrecv, ifp->nsent,
+             ifp->ndrop, ifp->nerr));
+  }
+#endif
+  // Handle physical interface up/down status
+  if (expired_1000ms && ifp->driver->up) {
+    bool up = ifp->driver->up(ifp);
+    bool current = ifp->state != MG_TCPIP_STATE_DOWN;
+    if (up != current) {
+      ifp->state = up == false               ? MG_TCPIP_STATE_DOWN
+                   : ifp->enable_dhcp_client ? MG_TCPIP_STATE_UP
+                                             : MG_TCPIP_STATE_READY;
+      if (!up && ifp->enable_dhcp_client) ifp->ip = 0;
+      onstatechange(ifp);
+    }
+    if (ifp->state == MG_TCPIP_STATE_DOWN) MG_ERROR(("Network is down"));
+  }
+  if (ifp->state == MG_TCPIP_STATE_DOWN) return;
+
+  // DHCP RFC-2131 (4.4)
+  if (ifp->state == MG_TCPIP_STATE_UP && expired_1000ms) {
+    tx_dhcp_discover(ifp);  // INIT (4.4.1)
+  } else if (expired_1000ms && ifp->state == MG_TCPIP_STATE_READY &&
+             ifp->lease_expire > 0) {  // BOUND / RENEWING / REBINDING
+    if (ifp->now >= ifp->lease_expire) {
+      ifp->state = MG_TCPIP_STATE_UP, ifp->ip = 0;  // expired, release IP
+      onstatechange(ifp);
+    } else if (ifp->now + 30UL * 60UL * 1000UL > ifp->lease_expire &&
+               ((ifp->now / 1000) % 60) == 0) {
+      // hack: 30 min before deadline, try to rebind (4.3.6) every min
+      tx_dhcp_request_re(ifp, (uint8_t *) broadcast, ifp->ip, 0xffffffff);
+    }  // TODO(): Handle T1 (RENEWING) and T2 (REBINDING) (4.4.5)
+  }
+
+  // Read data from the network
+  if (ifp->driver->rx != NULL) {  // Polling driver. We must call it
+    size_t len =
+        ifp->driver->rx(ifp->recv_queue.buf, ifp->recv_queue.size, ifp);
+    if (len > 0) {
+      ifp->nrecv++;
+      mg_tcpip_rx(ifp, ifp->recv_queue.buf, len);
+    }
+  } else {  // Interrupt-based driver. Fills recv queue itself
+    char *buf;
+    size_t len = mg_queue_next(&ifp->recv_queue, &buf);
+    if (len > 0) {
+      mg_tcpip_rx(ifp, buf, len);
+      mg_queue_del(&ifp->recv_queue, len);
+    }
+  }
+
+  // Process timeouts
+  for (c = ifp->mgr->conns; c != NULL; c = c->next) {
+    if (c->is_udp || c->is_listening || c->is_resolving) continue;
+    struct connstate *s = (struct connstate *) (c + 1);
+    uint32_t rem_ip;
+    memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t));
+    if (now > s->timer) {
+      if (s->ttype == MIP_TTYPE_ACK && s->acked != s->ack) {
+        MG_VERBOSE(("%lu ack %x %x", c->id, s->seq, s->ack));
+        tx_tcp(ifp, s->mac, rem_ip, TH_ACK, c->loc.port, c->rem.port,
+               mg_htonl(s->seq), mg_htonl(s->ack), NULL, 0);
+        s->acked = s->ack;
+      } else if (s->ttype == MIP_TTYPE_ARP) {
+        mg_error(c, "ARP timeout");
+      } else if (s->ttype == MIP_TTYPE_SYN) {
+        mg_error(c, "Connection timeout");
+      } else if (s->ttype == MIP_TTYPE_FIN) {
+        c->is_closing = 1;
+        continue;
+      } else {
+        if (s->tmiss++ > 2) {
+          mg_error(c, "keepalive");
+        } else {
+          MG_VERBOSE(("%lu keepalive", c->id));
+          tx_tcp(ifp, s->mac, rem_ip, TH_ACK, c->loc.port, c->rem.port,
+                 mg_htonl(s->seq - 1), mg_htonl(s->ack), NULL, 0);
+        }
+      }
+
+      settmout(c, MIP_TTYPE_KEEPALIVE);
+    }
+  }
+}
+
+// This function executes in interrupt context, thus it should copy data
+// somewhere fast. Note that newlib's malloc is not thread safe, thus use
+// our lock-free queue with preallocated buffer to copy data and return asap
+void mg_tcpip_qwrite(void *buf, size_t len, struct mg_tcpip_if *ifp) {
+  char *p;
+  if (mg_queue_book(&ifp->recv_queue, &p, len) >= len) {
+    memcpy(p, buf, len);
+    mg_queue_add(&ifp->recv_queue, len);
+    ifp->nrecv++;
+  } else {
+    ifp->ndrop++;
+  }
+}
+
+void mg_tcpip_init(struct mg_mgr *mgr, struct mg_tcpip_if *ifp) {
+  // If MAC address is not set, make a random one
+  if (ifp->mac[0] == 0 && ifp->mac[1] == 0 && ifp->mac[2] == 0 &&
+      ifp->mac[3] == 0 && ifp->mac[4] == 0 && ifp->mac[5] == 0) {
+    ifp->mac[0] = 0x02;  // Locally administered, unicast
+    mg_random(&ifp->mac[1], sizeof(ifp->mac) - 1);
+    MG_INFO(("MAC not set. Generated random: %M", mg_print_mac, ifp->mac));
+  }
+
+  if (ifp->driver->init && !ifp->driver->init(ifp)) {
+    MG_ERROR(("driver init failed"));
+  } else {
+    size_t framesize = 1540;
+    ifp->tx.buf = (char *) calloc(1, framesize), ifp->tx.len = framesize;
+    if (ifp->recv_queue.size == 0)
+      ifp->recv_queue.size = ifp->driver->rx ? framesize : 8192;
+    ifp->recv_queue.buf = (char *) calloc(1, ifp->recv_queue.size);
+    ifp->timer_1000ms = mg_millis();
+    mgr->priv = ifp;
+    ifp->mgr = mgr;
+    ifp->mtu = MG_TCPIP_MTU_DEFAULT;
+    mgr->extraconnsize = sizeof(struct connstate);
+    if (ifp->ip == 0) ifp->enable_dhcp_client = true;
+    memset(ifp->gwmac, 255, sizeof(ifp->gwmac));  // Set to broadcast
+    mg_random(&ifp->eport, sizeof(ifp->eport));   // Random from 0 to 65535
+    ifp->eport |= MG_EPHEMERAL_PORT_BASE;         // Random from
+                                           // MG_EPHEMERAL_PORT_BASE to 65535
+    if (ifp->tx.buf == NULL || ifp->recv_queue.buf == NULL) MG_ERROR(("OOM"));
+  }
+}
+
+void mg_tcpip_free(struct mg_tcpip_if *ifp) {
+  free(ifp->recv_queue.buf);
+  free(ifp->tx.buf);
+}
+
+static void send_syn(struct mg_connection *c) {
+  struct connstate *s = (struct connstate *) (c + 1);
+  uint32_t isn = mg_htonl((uint32_t) mg_ntohs(c->loc.port));
+  struct mg_tcpip_if *ifp = (struct mg_tcpip_if *) c->mgr->priv;
+  uint32_t rem_ip;
+  memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t));
+  tx_tcp(ifp, s->mac, rem_ip, TH_SYN, c->loc.port, c->rem.port, isn, 0, NULL,
+         0);
+}
+
+void mg_connect_resolved(struct mg_connection *c) {
+  struct mg_tcpip_if *ifp = (struct mg_tcpip_if *) c->mgr->priv;
+  uint32_t rem_ip;
+  memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t));
+  c->is_resolving = 0;
+  if (ifp->eport < MG_EPHEMERAL_PORT_BASE) ifp->eport = MG_EPHEMERAL_PORT_BASE;
+  memcpy(c->loc.ip, &ifp->ip, sizeof(uint32_t));
+  c->loc.port = mg_htons(ifp->eport++);
+  MG_DEBUG(("%lu %M -> %M", c->id, mg_print_ip_port, &c->loc, mg_print_ip_port,
+            &c->rem));
+  mg_call(c, MG_EV_RESOLVE, NULL);
+  if (c->is_udp && (rem_ip == 0xffffffff || rem_ip == (ifp->ip | ~ifp->mask))) {
+    struct connstate *s = (struct connstate *) (c + 1);
+    memset(s->mac, 0xFF, sizeof(s->mac));  // global or local broadcast
+  } else if (ifp->ip && ((rem_ip & ifp->mask) == (ifp->ip & ifp->mask))) {
+    // If we're in the same LAN, fire an ARP lookup.
+    MG_DEBUG(("%lu ARP lookup...", c->id));
+    arp_ask(ifp, rem_ip);
+    settmout(c, MIP_TTYPE_ARP);
+    c->is_arplooking = 1;
+    c->is_connecting = 1;
+  } else if ((*((uint8_t *) &rem_ip) & 0xE0) == 0xE0) {
+    struct connstate *s = (struct connstate *) (c + 1);  // 224 to 239, E0 to EF
+    uint8_t mcastp[3] = {0x01, 0x00, 0x5E};              // multicast group
+    memcpy(s->mac, mcastp, 3);
+    memcpy(s->mac + 3, ((uint8_t *) &rem_ip) + 1, 3);  // 23 LSb
+    s->mac[3] &= 0x7F;
+  } else {
+    struct connstate *s = (struct connstate *) (c + 1);
+    memcpy(s->mac, ifp->gwmac, sizeof(ifp->gwmac));
+    if (c->is_udp) {
+      mg_call(c, MG_EV_CONNECT, NULL);
+    } else {
+      send_syn(c);
+      settmout(c, MIP_TTYPE_SYN);
+      c->is_connecting = 1;
+    }
+  }
+}
+
+bool mg_open_listener(struct mg_connection *c, const char *url) {
+  c->loc.port = mg_htons(mg_url_port(url));
+  return true;
+}
+
+static void write_conn(struct mg_connection *c) {
+  long len = c->is_tls ? mg_tls_send(c, c->send.buf, c->send.len)
+                       : mg_io_send(c, c->send.buf, c->send.len);
+  if (len == MG_IO_ERR) {
+    mg_error(c, "tx err");
+  } else if (len > 0) {
+    mg_iobuf_del(&c->send, 0, (size_t) len);
+    mg_call(c, MG_EV_WRITE, &len);
+  }
+}
+
+static void init_closure(struct mg_connection *c) {
+  struct connstate *s = (struct connstate *) (c + 1);
+  if (c->is_udp == false && c->is_listening == false &&
+      c->is_connecting == false) {  // For TCP conns,
+    struct mg_tcpip_if *ifp =
+        (struct mg_tcpip_if *) c->mgr->priv;  // send TCP FIN
+    uint32_t rem_ip;
+    memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t));
+    tx_tcp(ifp, s->mac, rem_ip, TH_FIN | TH_ACK, c->loc.port, c->rem.port,
+           mg_htonl(s->seq), mg_htonl(s->ack), NULL, 0);
+    settmout(c, MIP_TTYPE_FIN);
+  }
+}
+
+static void close_conn(struct mg_connection *c) {
+  struct connstate *s = (struct connstate *) (c + 1);
+  mg_iobuf_free(&s->raw);  // For TLS connections, release raw data
+  mg_close_conn(c);
+}
+
+static bool can_write(struct mg_connection *c) {
+  return c->is_connecting == 0 && c->is_resolving == 0 && c->send.len > 0 &&
+         c->is_tls_hs == 0 && c->is_arplooking == 0;
+}
+
+void mg_mgr_poll(struct mg_mgr *mgr, int ms) {
+  struct mg_tcpip_if *ifp = (struct mg_tcpip_if *) mgr->priv;
+  struct mg_connection *c, *tmp;
+  uint64_t now = mg_millis();
+  mg_timer_poll(&mgr->timers, now);
+  if (ifp == NULL || ifp->driver == NULL) return;
+  mg_tcpip_poll(ifp, now);
+  for (c = mgr->conns; c != NULL; c = tmp) {
+    tmp = c->next;
+    struct connstate *s = (struct connstate *) (c + 1);
+    mg_call(c, MG_EV_POLL, &now);
+    MG_VERBOSE(("%lu .. %c%c%c%c%c", c->id, c->is_tls ? 'T' : 't',
+                c->is_connecting ? 'C' : 'c', c->is_tls_hs ? 'H' : 'h',
+                c->is_resolving ? 'R' : 'r', c->is_closing ? 'C' : 'c'));
+    if (c->is_tls && mg_tls_pending(c) > 0)
+      handle_tls_recv(c, (struct mg_iobuf *) &c->rtls);
+    if (can_write(c)) write_conn(c);
+    if (c->is_draining && c->send.len == 0 && s->ttype != MIP_TTYPE_FIN)
+      init_closure(c);
+    if (c->is_closing) close_conn(c);
+  }
+  (void) ms;
+}
+
+bool mg_send(struct mg_connection *c, const void *buf, size_t len) {
+  struct mg_tcpip_if *ifp = (struct mg_tcpip_if *) c->mgr->priv;
+  bool res = false;
+  uint32_t rem_ip;
+  memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t));
+  if (ifp->ip == 0 || ifp->state != MG_TCPIP_STATE_READY) {
+    mg_error(c, "net down");
+  } else if (c->is_udp) {
+    struct connstate *s = (struct connstate *) (c + 1);
+    len = trim_len(c, len);  // Trimming length if necessary
+    tx_udp(ifp, s->mac, ifp->ip, c->loc.port, rem_ip, c->rem.port, buf, len);
+    res = true;
+  } else {
+    res = mg_iobuf_add(&c->send, c->send.len, buf, len);
+  }
+  return res;
+}
+#endif  // MG_ENABLE_TCPIP
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/ota_dummy.c"
+#endif
+
+
+
+#if MG_OTA == MG_OTA_NONE
+bool mg_ota_begin(size_t new_firmware_size) {
+  (void) new_firmware_size;
+  return true;
+}
+bool mg_ota_write(const void *buf, size_t len) {
+  (void) buf, (void) len;
+  return true;
+}
+bool mg_ota_end(void) {
+  return true;
+}
+bool mg_ota_commit(void) {
+  return true;
+}
+bool mg_ota_rollback(void) {
+  return true;
+}
+int mg_ota_status(int fw) {
+  (void) fw;
+  return 0;
+}
+uint32_t mg_ota_crc32(int fw) {
+  (void) fw;
+  return 0;
+}
+uint32_t mg_ota_timestamp(int fw) {
+  (void) fw;
+  return 0;
+}
+size_t mg_ota_size(int fw) {
+  (void) fw;
+  return 0;
+}
+MG_IRAM void mg_ota_boot(void) {
+}
+#endif
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/ota_esp32.c"
+#endif
+
+
+#if MG_ARCH == MG_ARCH_ESP32 && MG_OTA == MG_OTA_ESP32
+
+static const esp_partition_t *s_ota_update_partition;
+static esp_ota_handle_t s_ota_update_handle;
+static bool s_ota_success;
+
+// Those empty macros do nothing, but mark places in the code which could
+// potentially trigger a watchdog reboot due to the log flash erase operation
+#define disable_wdt()
+#define enable_wdt()
+
+bool mg_ota_begin(size_t new_firmware_size) {
+  if (s_ota_update_partition != NULL) {
+    MG_ERROR(("Update in progress. Call mg_ota_end() ?"));
+    return false;
+  } else {
+    s_ota_success = false;
+    disable_wdt();
+    s_ota_update_partition = esp_ota_get_next_update_partition(NULL);
+    esp_err_t err = esp_ota_begin(s_ota_update_partition, new_firmware_size,
+                                  &s_ota_update_handle);
+    enable_wdt();
+    MG_DEBUG(("esp_ota_begin(): %d", err));
+    s_ota_success = (err == ESP_OK);
+  }
+  return s_ota_success;
+}
+
+bool mg_ota_write(const void *buf, size_t len) {
+  disable_wdt();
+  esp_err_t err = esp_ota_write(s_ota_update_handle, buf, len);
+  enable_wdt();
+  MG_INFO(("esp_ota_write(): %d", err));
+  s_ota_success = err == ESP_OK;
+  return s_ota_success;
+}
+
+bool mg_ota_end(void) {
+  esp_err_t err = esp_ota_end(s_ota_update_handle);
+  MG_DEBUG(("esp_ota_end(%p): %d", s_ota_update_handle, err));
+  if (s_ota_success && err == ESP_OK) {
+    err = esp_ota_set_boot_partition(s_ota_update_partition);
+    s_ota_success = (err == ESP_OK);
+  }
+  MG_DEBUG(("Finished ESP32 OTA, success: %d", s_ota_success));
+  s_ota_update_partition = NULL;
+  return s_ota_success;
+}
+
+#endif
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/ota_flash.c"
+#endif
+
+
+
+
+
+// This OTA implementation uses the internal flash API outlined in device.h
+// It splits flash into 2 equal partitions, and stores OTA status in the
+// last sector of the partition.
+
+#if MG_OTA == MG_OTA_FLASH
+
+#define MG_OTADATA_KEY 0xb07afed0
+
+static char *s_addr;      // Current address to write to
+static size_t s_size;     // Firmware size to flash. In-progress indicator
+static uint32_t s_crc32;  // Firmware checksum
+
+struct mg_otadata {
+  uint32_t crc32, size, timestamp, status;
+};
+
+bool mg_ota_begin(size_t new_firmware_size) {
+  bool ok = false;
+  if (s_size) {
+    MG_ERROR(("OTA already in progress. Call mg_ota_end()"));
+  } else {
+    size_t half = mg_flash_size() / 2, max = half - mg_flash_sector_size();
+    s_crc32 = 0;
+    s_addr = (char *) mg_flash_start() + half;
+    MG_DEBUG(("Firmware %lu bytes, max %lu", new_firmware_size, max));
+    if (new_firmware_size < max) {
+      ok = true;
+      s_size = new_firmware_size;
+      MG_INFO(("Starting OTA, firmware size %lu", s_size));
+    } else {
+      MG_ERROR(("Firmware %lu is too big to fit %lu", new_firmware_size, max));
+    }
+  }
+  return ok;
+}
+
+bool mg_ota_write(const void *buf, size_t len) {
+  bool ok = false;
+  if (s_size == 0) {
+    MG_ERROR(("OTA is not started, call mg_ota_begin()"));
+  } else {
+    size_t align = mg_flash_write_align();
+    size_t len_aligned_down = MG_ROUND_DOWN(len, align);
+    if (len_aligned_down) ok = mg_flash_write(s_addr, buf, len_aligned_down);
+    if (len_aligned_down < len) {
+      size_t left = len - len_aligned_down;
+      char tmp[align];
+      memset(tmp, 0xff, sizeof(tmp));
+      memcpy(tmp, (char *) buf + len_aligned_down, left);
+      ok = mg_flash_write(s_addr + len_aligned_down, tmp, sizeof(tmp));
+    }
+    s_crc32 = mg_crc32(s_crc32, (char *) buf, len);  // Update CRC
+    MG_DEBUG(("%#x %p %lu -> %d", s_addr - len, buf, len, ok));
+    s_addr += len;
+  }
+  return ok;
+}
+
+MG_IRAM static uint32_t mg_fwkey(int fw) {
+  uint32_t key = MG_OTADATA_KEY + fw;
+  int bank = mg_flash_bank();
+  if (bank == 2 && fw == MG_FIRMWARE_PREVIOUS) key--;
+  if (bank == 2 && fw == MG_FIRMWARE_CURRENT) key++;
+  return key;
+}
+
+bool mg_ota_end(void) {
+  char *base = (char *) mg_flash_start() + mg_flash_size() / 2;
+  bool ok = false;
+  if (s_size) {
+    size_t size = s_addr - base;
+    uint32_t crc32 = mg_crc32(0, base, s_size);
+    if (size == s_size && crc32 == s_crc32) {
+      uint32_t now = (uint32_t) (mg_now() / 1000);
+      struct mg_otadata od = {crc32, size, now, MG_OTA_FIRST_BOOT};
+      uint32_t key = mg_fwkey(MG_FIRMWARE_PREVIOUS);
+      ok = mg_flash_save(NULL, key, &od, sizeof(od));
+    }
+    MG_DEBUG(("CRC: %x/%x, size: %lu/%lu, status: %s", s_crc32, crc32, s_size,
+              size, ok ? "ok" : "fail"));
+    s_size = 0;
+    if (ok) ok = mg_flash_swap_bank();
+  }
+  MG_INFO(("Finishing OTA: %s", ok ? "ok" : "fail"));
+  return ok;
+}
+
+MG_IRAM static struct mg_otadata mg_otadata(int fw) {
+  uint32_t key = mg_fwkey(fw);
+  struct mg_otadata od = {};
+  MG_INFO(("Loading %s OTA data", fw == MG_FIRMWARE_CURRENT ? "curr" : "prev"));
+  mg_flash_load(NULL, key, &od, sizeof(od));
+  // MG_DEBUG(("Loaded OTA data. fw %d, bank %d, key %p", fw, bank, key));
+  // mg_hexdump(&od, sizeof(od));
+  return od;
+}
+
+int mg_ota_status(int fw) {
+  struct mg_otadata od = mg_otadata(fw);
+  return od.status;
+}
+uint32_t mg_ota_crc32(int fw) {
+  struct mg_otadata od = mg_otadata(fw);
+  return od.crc32;
+}
+uint32_t mg_ota_timestamp(int fw) {
+  struct mg_otadata od = mg_otadata(fw);
+  return od.timestamp;
+}
+size_t mg_ota_size(int fw) {
+  struct mg_otadata od = mg_otadata(fw);
+  return od.size;
+}
+
+MG_IRAM bool mg_ota_commit(void) {
+  bool ok = true;
+  struct mg_otadata od = mg_otadata(MG_FIRMWARE_CURRENT);
+  if (od.status != MG_OTA_COMMITTED) {
+    od.status = MG_OTA_COMMITTED;
+    MG_INFO(("Committing current firmware, OD size %lu", sizeof(od)));
+    ok = mg_flash_save(NULL, mg_fwkey(MG_FIRMWARE_CURRENT), &od, sizeof(od));
+  }
+  return ok;
+}
+
+bool mg_ota_rollback(void) {
+  MG_DEBUG(("Rolling firmware back"));
+  if (mg_flash_bank() == 0) {
+    // No dual bank support. Mark previous firmware as FIRST_BOOT
+    struct mg_otadata prev = mg_otadata(MG_FIRMWARE_PREVIOUS);
+    prev.status = MG_OTA_FIRST_BOOT;
+    return mg_flash_save(NULL, MG_OTADATA_KEY + MG_FIRMWARE_PREVIOUS, &prev,
+                         sizeof(prev));
+  } else {
+    return mg_flash_swap_bank();
+  }
+}
+
+MG_IRAM void mg_ota_boot(void) {
+  MG_INFO(("Booting. Flash bank: %d", mg_flash_bank()));
+  struct mg_otadata curr = mg_otadata(MG_FIRMWARE_CURRENT);
+  struct mg_otadata prev = mg_otadata(MG_FIRMWARE_PREVIOUS);
+
+  if (curr.status == MG_OTA_FIRST_BOOT) {
+    if (prev.status == MG_OTA_UNAVAILABLE) {
+      MG_INFO(("Setting previous firmware state to committed"));
+      prev.status = MG_OTA_COMMITTED;
+      mg_flash_save(NULL, mg_fwkey(MG_FIRMWARE_PREVIOUS), &prev, sizeof(prev));
+    }
+    curr.status = MG_OTA_UNCOMMITTED;
+    MG_INFO(("First boot, setting status to UNCOMMITTED"));
+    mg_flash_save(NULL, mg_fwkey(MG_FIRMWARE_CURRENT), &curr, sizeof(curr));
+  } else if (prev.status == MG_OTA_FIRST_BOOT && mg_flash_bank() == 0) {
+    // Swap paritions. Pray power does not disappear
+    size_t fs = mg_flash_size(), ss = mg_flash_sector_size();
+    char *partition1 = mg_flash_start();
+    char *partition2 = mg_flash_start() + fs / 2;
+    size_t ofs, max = fs / 2 - ss;  // Set swap size to the whole partition
+
+    if (curr.status != MG_OTA_UNAVAILABLE &&
+        prev.status != MG_OTA_UNAVAILABLE) {
+      // We know exact sizes of both firmwares.
+      // Shrink swap size to the MAX(firmware1, firmware2)
+      size_t sz = curr.size > prev.size ? curr.size : prev.size;
+      if (sz > 0 && sz < max) max = sz;
+    }
+
+    // MG_OTA_FIRST_BOOT -> MG_OTA_UNCOMMITTED
+    prev.status = MG_OTA_UNCOMMITTED;
+    mg_flash_save(NULL, MG_OTADATA_KEY + MG_FIRMWARE_CURRENT, &prev,
+                  sizeof(prev));
+    mg_flash_save(NULL, MG_OTADATA_KEY + MG_FIRMWARE_PREVIOUS, &curr,
+                  sizeof(curr));
+
+    MG_INFO(("Swapping partitions, size %u (%u sectors)", max, max / ss));
+    MG_INFO(("Do NOT power off..."));
+    mg_log_level = MG_LL_NONE;
+
+    // We use the last sector of partition2 for OTA data/config storage
+    // Therefore we can use last sector of partition1 for swapping
+    char *tmpsector = partition1 + fs / 2 - ss;  // Last sector of partition1
+    (void) tmpsector;
+    for (ofs = 0; ofs < max; ofs += ss) {
+      // mg_flash_erase(tmpsector);
+      mg_flash_write(tmpsector, partition1 + ofs, ss);
+      // mg_flash_erase(partition1 + ofs);
+      mg_flash_write(partition1 + ofs, partition2 + ofs, ss);
+      // mg_flash_erase(partition2 + ofs);
+      mg_flash_write(partition2 + ofs, tmpsector, ss);
+    }
+    mg_device_reset();
+  }
+}
+#endif
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/printf.c"
+#endif
+
+
+
+
+size_t mg_queue_vprintf(struct mg_queue *q, const char *fmt, va_list *ap) {
+  size_t len = mg_snprintf(NULL, 0, fmt, ap);
+  char *buf;
+  if (len == 0 || mg_queue_book(q, &buf, len + 1) < len + 1) {
+    len = 0;  // Nah. Not enough space
+  } else {
+    len = mg_vsnprintf((char *) buf, len + 1, fmt, ap);
+    mg_queue_add(q, len);
+  }
+  return len;
+}
+
+size_t mg_queue_printf(struct mg_queue *q, const char *fmt, ...) {
+  va_list ap;
+  size_t len;
+  va_start(ap, fmt);
+  len = mg_queue_vprintf(q, fmt, &ap);
+  va_end(ap);
+  return len;
+}
+
+static void mg_pfn_iobuf_private(char ch, void *param, bool expand) {
+  struct mg_iobuf *io = (struct mg_iobuf *) param;
+  if (expand && io->len + 2 > io->size) mg_iobuf_resize(io, io->len + 2);
+  if (io->len + 2 <= io->size) {
+    io->buf[io->len++] = (uint8_t) ch;
+    io->buf[io->len] = 0;
+  } else if (io->len < io->size) {
+    io->buf[io->len++] = 0;  // Guarantee to 0-terminate
+  }
+}
+
+static void mg_putchar_iobuf_static(char ch, void *param) {
+  mg_pfn_iobuf_private(ch, param, false);
+}
+
+void mg_pfn_iobuf(char ch, void *param) {
+  mg_pfn_iobuf_private(ch, param, true);
+}
+
+size_t mg_vsnprintf(char *buf, size_t len, const char *fmt, va_list *ap) {
+  struct mg_iobuf io = {(uint8_t *) buf, len, 0, 0};
+  size_t n = mg_vxprintf(mg_putchar_iobuf_static, &io, fmt, ap);
+  if (n < len) buf[n] = '\0';
+  return n;
+}
+
+size_t mg_snprintf(char *buf, size_t len, const char *fmt, ...) {
+  va_list ap;
+  size_t n;
+  va_start(ap, fmt);
+  n = mg_vsnprintf(buf, len, fmt, &ap);
+  va_end(ap);
+  return n;
+}
+
+char *mg_vmprintf(const char *fmt, va_list *ap) {
+  struct mg_iobuf io = {0, 0, 0, 256};
+  mg_vxprintf(mg_pfn_iobuf, &io, fmt, ap);
+  return (char *) io.buf;
+}
+
+char *mg_mprintf(const char *fmt, ...) {
+  char *s;
+  va_list ap;
+  va_start(ap, fmt);
+  s = mg_vmprintf(fmt, &ap);
+  va_end(ap);
+  return s;
+}
+
+void mg_pfn_stdout(char c, void *param) {
+  putchar(c);
+  (void) param;
+}
+
+static size_t print_ip4(void (*out)(char, void *), void *arg, uint8_t *p) {
+  return mg_xprintf(out, arg, "%d.%d.%d.%d", p[0], p[1], p[2], p[3]);
+}
+
+static size_t print_ip6(void (*out)(char, void *), void *arg, uint16_t *p) {
+  return mg_xprintf(out, arg, "[%x:%x:%x:%x:%x:%x:%x:%x]", mg_ntohs(p[0]),
+                    mg_ntohs(p[1]), mg_ntohs(p[2]), mg_ntohs(p[3]),
+                    mg_ntohs(p[4]), mg_ntohs(p[5]), mg_ntohs(p[6]),
+                    mg_ntohs(p[7]));
+}
+
+size_t mg_print_ip4(void (*out)(char, void *), void *arg, va_list *ap) {
+  uint8_t *p = va_arg(*ap, uint8_t *);
+  return print_ip4(out, arg, p);
+}
+
+size_t mg_print_ip6(void (*out)(char, void *), void *arg, va_list *ap) {
+  uint16_t *p = va_arg(*ap, uint16_t *);
+  return print_ip6(out, arg, p);
+}
+
+size_t mg_print_ip(void (*out)(char, void *), void *arg, va_list *ap) {
+  struct mg_addr *addr = va_arg(*ap, struct mg_addr *);
+  if (addr->is_ip6) return print_ip6(out, arg, (uint16_t *) addr->ip);
+  return print_ip4(out, arg, (uint8_t *) &addr->ip);
+}
+
+size_t mg_print_ip_port(void (*out)(char, void *), void *arg, va_list *ap) {
+  struct mg_addr *a = va_arg(*ap, struct mg_addr *);
+  return mg_xprintf(out, arg, "%M:%hu", mg_print_ip, a, mg_ntohs(a->port));
+}
+
+size_t mg_print_mac(void (*out)(char, void *), void *arg, va_list *ap) {
+  uint8_t *p = va_arg(*ap, uint8_t *);
+  return mg_xprintf(out, arg, "%02x:%02x:%02x:%02x:%02x:%02x", p[0], p[1], p[2],
+                    p[3], p[4], p[5]);
+}
+
+static char mg_esc(int c, bool esc) {
+  const char *p, *esc1 = "\b\f\n\r\t\\\"", *esc2 = "bfnrt\\\"";
+  for (p = esc ? esc1 : esc2; *p != '\0'; p++) {
+    if (*p == c) return esc ? esc2[p - esc1] : esc1[p - esc2];
+  }
+  return 0;
+}
+
+static char mg_escape(int c) {
+  return mg_esc(c, true);
+}
+
+static size_t qcpy(void (*out)(char, void *), void *ptr, char *buf,
+                   size_t len) {
+  size_t i = 0, extra = 0;
+  for (i = 0; i < len && buf[i] != '\0'; i++) {
+    char c = mg_escape(buf[i]);
+    if (c) {
+      out('\\', ptr), out(c, ptr), extra++;
+    } else {
+      out(buf[i], ptr);
+    }
+  }
+  return i + extra;
+}
+
+static size_t bcpy(void (*out)(char, void *), void *arg, uint8_t *buf,
+                   size_t len) {
+  size_t i, j, n = 0;
+  const char *t =
+      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+  for (i = 0; i < len; i += 3) {
+    uint8_t c1 = buf[i], c2 = i + 1 < len ? buf[i + 1] : 0,
+            c3 = i + 2 < len ? buf[i + 2] : 0;
+    char tmp[4] = {t[c1 >> 2], t[(c1 & 3) << 4 | (c2 >> 4)], '=', '='};
+    if (i + 1 < len) tmp[2] = t[(c2 & 15) << 2 | (c3 >> 6)];
+    if (i + 2 < len) tmp[3] = t[c3 & 63];
+    for (j = 0; j < sizeof(tmp) && tmp[j] != '\0'; j++) out(tmp[j], arg);
+    n += j;
+  }
+  return n;
+}
+
+size_t mg_print_hex(void (*out)(char, void *), void *arg, va_list *ap) {
+  size_t bl = (size_t) va_arg(*ap, int);
+  uint8_t *p = va_arg(*ap, uint8_t *);
+  const char *hex = "0123456789abcdef";
+  size_t j;
+  for (j = 0; j < bl; j++) {
+    out(hex[(p[j] >> 4) & 0x0F], arg);
+    out(hex[p[j] & 0x0F], arg);
+  }
+  return 2 * bl;
+}
+size_t mg_print_base64(void (*out)(char, void *), void *arg, va_list *ap) {
+  size_t len = (size_t) va_arg(*ap, int);
+  uint8_t *buf = va_arg(*ap, uint8_t *);
+  return bcpy(out, arg, buf, len);
+}
+
+size_t mg_print_esc(void (*out)(char, void *), void *arg, va_list *ap) {
+  size_t len = (size_t) va_arg(*ap, int);
+  char *p = va_arg(*ap, char *);
+  if (len == 0) len = p == NULL ? 0 : strlen(p);
+  return qcpy(out, arg, p, len);
+}
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/queue.c"
+#endif
+
+
+
+#if (defined(__GNUC__) && (__GNUC__ > 4) ||                                \
+     (defined(__GNUC_MINOR__) && __GNUC__ == 4 && __GNUC_MINOR__ >= 1)) || \
+    defined(__clang__)
+#define MG_MEMORY_BARRIER() __sync_synchronize()
+#elif defined(_MSC_VER) && _MSC_VER >= 1700
+#define MG_MEMORY_BARRIER() MemoryBarrier()
+#elif !defined(MG_MEMORY_BARRIER)
+#define MG_MEMORY_BARRIER()
+#endif
+
+// Every message in a queue is prepended by a 32-bit message length (ML).
+// If ML is 0, then it is the end, and reader must wrap to the beginning.
+//
+//  Queue when q->tail <= q->head:
+//  |----- free -----| ML | message1 | ML | message2 |  ----- free ------|
+//  ^                ^                               ^                   ^
+// buf              tail                            head                len
+//
+//  Queue when q->tail > q->head:
+//  | ML | message2 |----- free ------| ML | message1 | 0 |---- free ----|
+//  ^               ^                 ^                                  ^
+// buf             head              tail                               len
+
+void mg_queue_init(struct mg_queue *q, char *buf, size_t size) {
+  q->size = size;
+  q->buf = buf;
+  q->head = q->tail = 0;
+}
+
+static size_t mg_queue_read_len(struct mg_queue *q) {
+  uint32_t n = 0;
+  MG_MEMORY_BARRIER();
+  memcpy(&n, q->buf + q->tail, sizeof(n));
+  assert(q->tail + n + sizeof(n) <= q->size);
+  return n;
+}
+
+static void mg_queue_write_len(struct mg_queue *q, size_t len) {
+  uint32_t n = (uint32_t) len;
+  memcpy(q->buf + q->head, &n, sizeof(n));
+  MG_MEMORY_BARRIER();
+}
+
+size_t mg_queue_book(struct mg_queue *q, char **buf, size_t len) {
+  size_t space = 0, hs = sizeof(uint32_t) * 2;  // *2 is for the 0 marker
+  if (q->head >= q->tail && q->head + len + hs <= q->size) {
+    space = q->size - q->head - hs;  // There is enough space
+  } else if (q->head >= q->tail && q->tail > hs) {
+    mg_queue_write_len(q, 0);  // Not enough space ahead
+    q->head = 0;               // Wrap head to the beginning
+  }
+  if (q->head + hs + len < q->tail) space = q->tail - q->head - hs;
+  if (buf != NULL) *buf = q->buf + q->head + sizeof(uint32_t);
+  return space;
+}
+
+size_t mg_queue_next(struct mg_queue *q, char **buf) {
+  size_t len = 0;
+  if (q->tail != q->head) {
+    len = mg_queue_read_len(q);
+    if (len == 0) {  // Zero (head wrapped) ?
+      q->tail = 0;   // Reset tail to the start
+      if (q->head > q->tail) len = mg_queue_read_len(q);  // Read again
+    }
+  }
+  if (buf != NULL) *buf = q->buf + q->tail + sizeof(uint32_t);
+  assert(q->tail + len <= q->size);
+  return len;
+}
+
+void mg_queue_add(struct mg_queue *q, size_t len) {
+  assert(len > 0);
+  mg_queue_write_len(q, len);
+  assert(q->head + sizeof(uint32_t) * 2 + len <= q->size);
+  q->head += len + sizeof(uint32_t);
+}
+
+void mg_queue_del(struct mg_queue *q, size_t len) {
+  q->tail += len + sizeof(uint32_t);
+  assert(q->tail + sizeof(uint32_t) <= q->size);
+}
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/rpc.c"
+#endif
+
+
+
+void mg_rpc_add(struct mg_rpc **head, struct mg_str method,
+                void (*fn)(struct mg_rpc_req *), void *fn_data) {
+  struct mg_rpc *rpc = (struct mg_rpc *) calloc(1, sizeof(*rpc));
+  if (rpc != NULL) {
+    rpc->method.buf = mg_mprintf("%.*s", method.len, method.buf);
+    rpc->method.len = method.len;
+    rpc->fn = fn;
+    rpc->fn_data = fn_data;
+    rpc->next = *head, *head = rpc;
+  }
+}
+
+void mg_rpc_del(struct mg_rpc **head, void (*fn)(struct mg_rpc_req *)) {
+  struct mg_rpc *r;
+  while ((r = *head) != NULL) {
+    if (r->fn == fn || fn == NULL) {
+      *head = r->next;
+      free((void *) r->method.buf);
+      free(r);
+    } else {
+      head = &(*head)->next;
+    }
+  }
+}
+
+static void mg_rpc_call(struct mg_rpc_req *r, struct mg_str method) {
+  struct mg_rpc *h = r->head == NULL ? NULL : *r->head;
+  while (h != NULL && !mg_match(method, h->method, NULL)) h = h->next;
+  if (h != NULL) {
+    r->rpc = h;
+    h->fn(r);
+  } else {
+    mg_rpc_err(r, -32601, "\"%.*s not found\"", (int) method.len, method.buf);
+  }
+}
+
+void mg_rpc_process(struct mg_rpc_req *r) {
+  int len, off = mg_json_get(r->frame, "$.method", &len);
+  if (off > 0 && r->frame.buf[off] == '"') {
+    struct mg_str method = mg_str_n(&r->frame.buf[off + 1], (size_t) len - 2);
+    mg_rpc_call(r, method);
+  } else if ((off = mg_json_get(r->frame, "$.result", &len)) > 0 ||
+             (off = mg_json_get(r->frame, "$.error", &len)) > 0) {
+    mg_rpc_call(r, mg_str(""));  // JSON response! call "" method handler
+  } else {
+    mg_rpc_err(r, -32700, "%m", mg_print_esc, (int) r->frame.len,
+               r->frame.buf);  // Invalid
+  }
+}
+
+void mg_rpc_vok(struct mg_rpc_req *r, const char *fmt, va_list *ap) {
+  int len, off = mg_json_get(r->frame, "$.id", &len);
+  if (off > 0) {
+    mg_xprintf(r->pfn, r->pfn_data, "{%m:%.*s,%m:", mg_print_esc, 0, "id", len,
+               &r->frame.buf[off], mg_print_esc, 0, "result");
+    mg_vxprintf(r->pfn, r->pfn_data, fmt == NULL ? "null" : fmt, ap);
+    mg_xprintf(r->pfn, r->pfn_data, "}");
+  }
+}
+
+void mg_rpc_ok(struct mg_rpc_req *r, const char *fmt, ...) {
+  va_list ap;
+  va_start(ap, fmt);
+  mg_rpc_vok(r, fmt, &ap);
+  va_end(ap);
+}
+
+void mg_rpc_verr(struct mg_rpc_req *r, int code, const char *fmt, va_list *ap) {
+  int len, off = mg_json_get(r->frame, "$.id", &len);
+  mg_xprintf(r->pfn, r->pfn_data, "{");
+  if (off > 0) {
+    mg_xprintf(r->pfn, r->pfn_data, "%m:%.*s,", mg_print_esc, 0, "id", len,
+               &r->frame.buf[off]);
+  }
+  mg_xprintf(r->pfn, r->pfn_data, "%m:{%m:%d,%m:", mg_print_esc, 0, "error",
+             mg_print_esc, 0, "code", code, mg_print_esc, 0, "message");
+  mg_vxprintf(r->pfn, r->pfn_data, fmt == NULL ? "null" : fmt, ap);
+  mg_xprintf(r->pfn, r->pfn_data, "}}");
+}
+
+void mg_rpc_err(struct mg_rpc_req *r, int code, const char *fmt, ...) {
+  va_list ap;
+  va_start(ap, fmt);
+  mg_rpc_verr(r, code, fmt, &ap);
+  va_end(ap);
+}
+
+static size_t print_methods(mg_pfn_t pfn, void *pfn_data, va_list *ap) {
+  struct mg_rpc *h, **head = (struct mg_rpc **) va_arg(*ap, void **);
+  size_t len = 0;
+  for (h = *head; h != NULL; h = h->next) {
+    if (h->method.len == 0) continue;  // Ignore response handler
+    len += mg_xprintf(pfn, pfn_data, "%s%m", h == *head ? "" : ",",
+                      mg_print_esc, (int) h->method.len, h->method.buf);
+  }
+  return len;
+}
+
+void mg_rpc_list(struct mg_rpc_req *r) {
+  mg_rpc_ok(r, "[%M]", print_methods, r->head);
+}
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/sha1.c"
+#endif
+/* Copyright(c) By Steve Reid <steve@edmweb.com> */
+/* 100% Public Domain */
+
+
+
+union char64long16 {
+  unsigned char c[64];
+  uint32_t l[16];
+};
+
+#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))
+
+static uint32_t blk0(union char64long16 *block, int i) {
+  if (MG_BIG_ENDIAN) {
+  } else {
+    block->l[i] = (rol(block->l[i], 24) & 0xFF00FF00) |
+                  (rol(block->l[i], 8) & 0x00FF00FF);
+  }
+  return block->l[i];
+}
+
+/* Avoid redefine warning (ARM /usr/include/sys/ucontext.h define R0~R4) */
+#undef blk
+#undef R0
+#undef R1
+#undef R2
+#undef R3
+#undef R4
+
+#define blk(i)                                                               \
+  (block->l[i & 15] = rol(block->l[(i + 13) & 15] ^ block->l[(i + 8) & 15] ^ \
+                              block->l[(i + 2) & 15] ^ block->l[i & 15],     \
+                          1))
+#define R0(v, w, x, y, z, i)                                          \
+  z += ((w & (x ^ y)) ^ y) + blk0(block, i) + 0x5A827999 + rol(v, 5); \
+  w = rol(w, 30);
+#define R1(v, w, x, y, z, i)                                  \
+  z += ((w & (x ^ y)) ^ y) + blk(i) + 0x5A827999 + rol(v, 5); \
+  w = rol(w, 30);
+#define R2(v, w, x, y, z, i)                          \
+  z += (w ^ x ^ y) + blk(i) + 0x6ED9EBA1 + rol(v, 5); \
+  w = rol(w, 30);
+#define R3(v, w, x, y, z, i)                                        \
+  z += (((w | x) & y) | (w & x)) + blk(i) + 0x8F1BBCDC + rol(v, 5); \
+  w = rol(w, 30);
+#define R4(v, w, x, y, z, i)                          \
+  z += (w ^ x ^ y) + blk(i) + 0xCA62C1D6 + rol(v, 5); \
+  w = rol(w, 30);
+
+static void mg_sha1_transform(uint32_t state[5],
+                              const unsigned char *buffer) {
+  uint32_t a, b, c, d, e;
+  union char64long16 block[1];
+
+  memcpy(block, buffer, 64);
+  a = state[0];
+  b = state[1];
+  c = state[2];
+  d = state[3];
+  e = state[4];
+  R0(a, b, c, d, e, 0);
+  R0(e, a, b, c, d, 1);
+  R0(d, e, a, b, c, 2);
+  R0(c, d, e, a, b, 3);
+  R0(b, c, d, e, a, 4);
+  R0(a, b, c, d, e, 5);
+  R0(e, a, b, c, d, 6);
+  R0(d, e, a, b, c, 7);
+  R0(c, d, e, a, b, 8);
+  R0(b, c, d, e, a, 9);
+  R0(a, b, c, d, e, 10);
+  R0(e, a, b, c, d, 11);
+  R0(d, e, a, b, c, 12);
+  R0(c, d, e, a, b, 13);
+  R0(b, c, d, e, a, 14);
+  R0(a, b, c, d, e, 15);
+  R1(e, a, b, c, d, 16);
+  R1(d, e, a, b, c, 17);
+  R1(c, d, e, a, b, 18);
+  R1(b, c, d, e, a, 19);
+  R2(a, b, c, d, e, 20);
+  R2(e, a, b, c, d, 21);
+  R2(d, e, a, b, c, 22);
+  R2(c, d, e, a, b, 23);
+  R2(b, c, d, e, a, 24);
+  R2(a, b, c, d, e, 25);
+  R2(e, a, b, c, d, 26);
+  R2(d, e, a, b, c, 27);
+  R2(c, d, e, a, b, 28);
+  R2(b, c, d, e, a, 29);
+  R2(a, b, c, d, e, 30);
+  R2(e, a, b, c, d, 31);
+  R2(d, e, a, b, c, 32);
+  R2(c, d, e, a, b, 33);
+  R2(b, c, d, e, a, 34);
+  R2(a, b, c, d, e, 35);
+  R2(e, a, b, c, d, 36);
+  R2(d, e, a, b, c, 37);
+  R2(c, d, e, a, b, 38);
+  R2(b, c, d, e, a, 39);
+  R3(a, b, c, d, e, 40);
+  R3(e, a, b, c, d, 41);
+  R3(d, e, a, b, c, 42);
+  R3(c, d, e, a, b, 43);
+  R3(b, c, d, e, a, 44);
+  R3(a, b, c, d, e, 45);
+  R3(e, a, b, c, d, 46);
+  R3(d, e, a, b, c, 47);
+  R3(c, d, e, a, b, 48);
+  R3(b, c, d, e, a, 49);
+  R3(a, b, c, d, e, 50);
+  R3(e, a, b, c, d, 51);
+  R3(d, e, a, b, c, 52);
+  R3(c, d, e, a, b, 53);
+  R3(b, c, d, e, a, 54);
+  R3(a, b, c, d, e, 55);
+  R3(e, a, b, c, d, 56);
+  R3(d, e, a, b, c, 57);
+  R3(c, d, e, a, b, 58);
+  R3(b, c, d, e, a, 59);
+  R4(a, b, c, d, e, 60);
+  R4(e, a, b, c, d, 61);
+  R4(d, e, a, b, c, 62);
+  R4(c, d, e, a, b, 63);
+  R4(b, c, d, e, a, 64);
+  R4(a, b, c, d, e, 65);
+  R4(e, a, b, c, d, 66);
+  R4(d, e, a, b, c, 67);
+  R4(c, d, e, a, b, 68);
+  R4(b, c, d, e, a, 69);
+  R4(a, b, c, d, e, 70);
+  R4(e, a, b, c, d, 71);
+  R4(d, e, a, b, c, 72);
+  R4(c, d, e, a, b, 73);
+  R4(b, c, d, e, a, 74);
+  R4(a, b, c, d, e, 75);
+  R4(e, a, b, c, d, 76);
+  R4(d, e, a, b, c, 77);
+  R4(c, d, e, a, b, 78);
+  R4(b, c, d, e, a, 79);
+  state[0] += a;
+  state[1] += b;
+  state[2] += c;
+  state[3] += d;
+  state[4] += e;
+  /* Erase working structures. The order of operations is important,
+   * used to ensure that compiler doesn't optimize those out. */
+  memset(block, 0, sizeof(block));
+  a = b = c = d = e = 0;
+  (void) a;
+  (void) b;
+  (void) c;
+  (void) d;
+  (void) e;
+}
+
+void mg_sha1_init(mg_sha1_ctx *context) {
+  context->state[0] = 0x67452301;
+  context->state[1] = 0xEFCDAB89;
+  context->state[2] = 0x98BADCFE;
+  context->state[3] = 0x10325476;
+  context->state[4] = 0xC3D2E1F0;
+  context->count[0] = context->count[1] = 0;
+}
+
+void mg_sha1_update(mg_sha1_ctx *context, const unsigned char *data,
+                    size_t len) {
+  size_t i, j;
+
+  j = context->count[0];
+  if ((context->count[0] += (uint32_t) len << 3) < j) context->count[1]++;
+  context->count[1] += (uint32_t) (len >> 29);
+  j = (j >> 3) & 63;
+  if ((j + len) > 63) {
+    memcpy(&context->buffer[j], data, (i = 64 - j));
+    mg_sha1_transform(context->state, context->buffer);
+    for (; i + 63 < len; i += 64) {
+      mg_sha1_transform(context->state, &data[i]);
+    }
+    j = 0;
+  } else
+    i = 0;
+  memcpy(&context->buffer[j], &data[i], len - i);
+}
+
+void mg_sha1_final(unsigned char digest[20], mg_sha1_ctx *context) {
+  unsigned i;
+  unsigned char finalcount[8], c;
+
+  for (i = 0; i < 8; i++) {
+    finalcount[i] = (unsigned char) ((context->count[(i >= 4 ? 0 : 1)] >>
+                                      ((3 - (i & 3)) * 8)) &
+                                     255);
+  }
+  c = 0200;
+  mg_sha1_update(context, &c, 1);
+  while ((context->count[0] & 504) != 448) {
+    c = 0000;
+    mg_sha1_update(context, &c, 1);
+  }
+  mg_sha1_update(context, finalcount, 8);
+  for (i = 0; i < 20; i++) {
+    digest[i] =
+        (unsigned char) ((context->state[i >> 2] >> ((3 - (i & 3)) * 8)) & 255);
+  }
+  memset(context, '\0', sizeof(*context));
+  memset(&finalcount, '\0', sizeof(finalcount));
+}
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/sha256.c"
+#endif
+// https://github.com/B-Con/crypto-algorithms
+// Author:     Brad Conte (brad AT bradconte.com)
+// Disclaimer: This code is presented "as is" without any guarantees.
+// Details:    Defines the API for the corresponding SHA1 implementation.
+// Copyright:  public domain
+
+
+
+#define ror(x, n) (((x) >> (n)) | ((x) << (32 - (n))))
+#define ch(x, y, z) (((x) & (y)) ^ (~(x) & (z)))
+#define maj(x, y, z) (((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)))
+#define ep0(x) (ror(x, 2) ^ ror(x, 13) ^ ror(x, 22))
+#define ep1(x) (ror(x, 6) ^ ror(x, 11) ^ ror(x, 25))
+#define sig0(x) (ror(x, 7) ^ ror(x, 18) ^ ((x) >> 3))
+#define sig1(x) (ror(x, 17) ^ ror(x, 19) ^ ((x) >> 10))
+
+static const uint32_t mg_sha256_k[64] = {
+    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
+    0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
+    0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
+    0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
+    0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
+    0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
+    0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
+    0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
+    0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
+    0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
+    0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2};
+
+void mg_sha256_init(mg_sha256_ctx *ctx) {
+  ctx->len = 0;
+  ctx->bits = 0;
+  ctx->state[0] = 0x6a09e667;
+  ctx->state[1] = 0xbb67ae85;
+  ctx->state[2] = 0x3c6ef372;
+  ctx->state[3] = 0xa54ff53a;
+  ctx->state[4] = 0x510e527f;
+  ctx->state[5] = 0x9b05688c;
+  ctx->state[6] = 0x1f83d9ab;
+  ctx->state[7] = 0x5be0cd19;
+}
+
+static void mg_sha256_chunk(mg_sha256_ctx *ctx) {
+  int i, j;
+  uint32_t a, b, c, d, e, f, g, h;
+  uint32_t m[64];
+  for (i = 0, j = 0; i < 16; ++i, j += 4)
+    m[i] = (uint32_t) (((uint32_t) ctx->buffer[j] << 24) |
+                       ((uint32_t) ctx->buffer[j + 1] << 16) |
+                       ((uint32_t) ctx->buffer[j + 2] << 8) |
+                       ((uint32_t) ctx->buffer[j + 3]));
+  for (; i < 64; ++i)
+    m[i] = sig1(m[i - 2]) + m[i - 7] + sig0(m[i - 15]) + m[i - 16];
+
+  a = ctx->state[0];
+  b = ctx->state[1];
+  c = ctx->state[2];
+  d = ctx->state[3];
+  e = ctx->state[4];
+  f = ctx->state[5];
+  g = ctx->state[6];
+  h = ctx->state[7];
+
+  for (i = 0; i < 64; ++i) {
+    uint32_t t1 = h + ep1(e) + ch(e, f, g) + mg_sha256_k[i] + m[i];
+    uint32_t t2 = ep0(a) + maj(a, b, c);
+    h = g;
+    g = f;
+    f = e;
+    e = d + t1;
+    d = c;
+    c = b;
+    b = a;
+    a = t1 + t2;
+  }
+
+  ctx->state[0] += a;
+  ctx->state[1] += b;
+  ctx->state[2] += c;
+  ctx->state[3] += d;
+  ctx->state[4] += e;
+  ctx->state[5] += f;
+  ctx->state[6] += g;
+  ctx->state[7] += h;
+}
+
+void mg_sha256_update(mg_sha256_ctx *ctx, const unsigned char *data,
+                      size_t len) {
+  size_t i;
+  for (i = 0; i < len; i++) {
+    ctx->buffer[ctx->len] = data[i];
+    if ((++ctx->len) == 64) {
+      mg_sha256_chunk(ctx);
+      ctx->bits += 512;
+      ctx->len = 0;
+    }
+  }
+}
+
+// TODO: make final reusable (remove side effects)
+void mg_sha256_final(unsigned char digest[32], mg_sha256_ctx *ctx) {
+  uint32_t i = ctx->len;
+  if (i < 56) {
+    ctx->buffer[i++] = 0x80;
+    while (i < 56) {
+      ctx->buffer[i++] = 0x00;
+    }
+  } else {
+    ctx->buffer[i++] = 0x80;
+    while (i < 64) {
+      ctx->buffer[i++] = 0x00;
+    }
+    mg_sha256_chunk(ctx);
+    memset(ctx->buffer, 0, 56);
+  }
+
+  ctx->bits += ctx->len * 8;
+  ctx->buffer[63] = (uint8_t) ((ctx->bits) & 0xff);
+  ctx->buffer[62] = (uint8_t) ((ctx->bits >> 8) & 0xff);
+  ctx->buffer[61] = (uint8_t) ((ctx->bits >> 16) & 0xff);
+  ctx->buffer[60] = (uint8_t) ((ctx->bits >> 24) & 0xff);
+  ctx->buffer[59] = (uint8_t) ((ctx->bits >> 32) & 0xff);
+  ctx->buffer[58] = (uint8_t) ((ctx->bits >> 40) & 0xff);
+  ctx->buffer[57] = (uint8_t) ((ctx->bits >> 48) & 0xff);
+  ctx->buffer[56] = (uint8_t) ((ctx->bits >> 56) & 0xff);
+  mg_sha256_chunk(ctx);
+
+  for (i = 0; i < 4; ++i) {
+    digest[i] = (uint8_t) ((ctx->state[0] >> (24 - i * 8)) & 0xff);
+    digest[i + 4] = (uint8_t) ((ctx->state[1] >> (24 - i * 8)) & 0xff);
+    digest[i + 8] = (uint8_t) ((ctx->state[2] >> (24 - i * 8)) & 0xff);
+    digest[i + 12] = (uint8_t) ((ctx->state[3] >> (24 - i * 8)) & 0xff);
+    digest[i + 16] = (uint8_t) ((ctx->state[4] >> (24 - i * 8)) & 0xff);
+    digest[i + 20] = (uint8_t) ((ctx->state[5] >> (24 - i * 8)) & 0xff);
+    digest[i + 24] = (uint8_t) ((ctx->state[6] >> (24 - i * 8)) & 0xff);
+    digest[i + 28] = (uint8_t) ((ctx->state[7] >> (24 - i * 8)) & 0xff);
+  }
+}
+
+void mg_hmac_sha256(uint8_t dst[32], uint8_t *key, size_t keysz, uint8_t *data,
+                    size_t datasz) {
+  mg_sha256_ctx ctx;
+  uint8_t k[64] = {0};
+  uint8_t o_pad[64], i_pad[64];
+  unsigned int i;
+  memset(i_pad, 0x36, sizeof(i_pad));
+  memset(o_pad, 0x5c, sizeof(o_pad));
+  if (keysz < 64) {
+    if (keysz > 0) memmove(k, key, keysz);
+  } else {
+    mg_sha256_init(&ctx);
+    mg_sha256_update(&ctx, key, keysz);
+    mg_sha256_final(k, &ctx);
+  }
+  for (i = 0; i < sizeof(k); i++) {
+    i_pad[i] ^= k[i];
+    o_pad[i] ^= k[i];
+  }
+  mg_sha256_init(&ctx);
+  mg_sha256_update(&ctx, i_pad, sizeof(i_pad));
+  mg_sha256_update(&ctx, data, datasz);
+  mg_sha256_final(dst, &ctx);
+  mg_sha256_init(&ctx);
+  mg_sha256_update(&ctx, o_pad, sizeof(o_pad));
+  mg_sha256_update(&ctx, dst, 32);
+  mg_sha256_final(dst, &ctx);
+}
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/sntp.c"
+#endif
+
+
+
+
+
+
+#define SNTP_TIME_OFFSET 2208988800U  // (1970 - 1900) in seconds
+#define SNTP_MAX_FRAC 4294967295.0    // 2 ** 32 - 1
+
+static int64_t gettimestamp(const uint32_t *data) {
+  uint32_t sec = mg_ntohl(data[0]), frac = mg_ntohl(data[1]);
+  if (sec) sec -= SNTP_TIME_OFFSET;
+  return ((int64_t) sec) * 1000 + (int64_t) (frac / SNTP_MAX_FRAC * 1000.0);
+}
+
+int64_t mg_sntp_parse(const unsigned char *buf, size_t len) {
+  int64_t res = -1;
+  int mode = len > 0 ? buf[0] & 7 : 0;
+  int version = len > 0 ? (buf[0] >> 3) & 7 : 0;
+  if (len < 48) {
+    MG_ERROR(("%s", "corrupt packet"));
+  } else if (mode != 4 && mode != 5) {
+    MG_ERROR(("%s", "not a server reply"));
+  } else if (buf[1] == 0) {
+    MG_ERROR(("%s", "server sent a kiss of death"));
+  } else if (version == 4 || version == 3) {
+    // int64_t ref = gettimestamp((uint32_t *) &buf[16]);
+    int64_t t0 = gettimestamp((uint32_t *) &buf[24]);
+    int64_t t1 = gettimestamp((uint32_t *) &buf[32]);
+    int64_t t2 = gettimestamp((uint32_t *) &buf[40]);
+    int64_t t3 = (int64_t) mg_millis();
+    int64_t delta = (t3 - t0) - (t2 - t1);
+    MG_VERBOSE(("%lld %lld %lld %lld delta:%lld", t0, t1, t2, t3, delta));
+    res = t2 + delta / 2;
+  } else {
+    MG_ERROR(("unexpected version: %d", version));
+  }
+  return res;
+}
+
+static void sntp_cb(struct mg_connection *c, int ev, void *ev_data) {
+  if (ev == MG_EV_READ) {
+    int64_t milliseconds = mg_sntp_parse(c->recv.buf, c->recv.len);
+    if (milliseconds > 0) {
+      MG_DEBUG(("%lu got time: %lld ms from epoch", c->id, milliseconds));
+      mg_call(c, MG_EV_SNTP_TIME, (uint64_t *) &milliseconds);
+      MG_VERBOSE(("%u.%u", (unsigned) (milliseconds / 1000),
+                  (unsigned) (milliseconds % 1000)));
+    }
+    mg_iobuf_del(&c->recv, 0, c->recv.len);  // Free receive buffer
+  } else if (ev == MG_EV_CONNECT) {
+    mg_sntp_request(c);
+  } else if (ev == MG_EV_CLOSE) {
+  }
+  (void) ev_data;
+}
+
+void mg_sntp_request(struct mg_connection *c) {
+  if (c->is_resolving) {
+    MG_ERROR(("%lu wait until resolved", c->id));
+  } else {
+    int64_t now = (int64_t) mg_millis();  // Use int64_t, for vc98
+    uint8_t buf[48] = {0};
+    uint32_t *t = (uint32_t *) &buf[40];
+    double frac = ((double) (now % 1000)) / 1000.0 * SNTP_MAX_FRAC;
+    buf[0] = (0 << 6) | (4 << 3) | 3;
+    t[0] = mg_htonl((uint32_t) (now / 1000) + SNTP_TIME_OFFSET);
+    t[1] = mg_htonl((uint32_t) frac);
+    mg_send(c, buf, sizeof(buf));
+  }
+}
+
+struct mg_connection *mg_sntp_connect(struct mg_mgr *mgr, const char *url,
+                                      mg_event_handler_t fn, void *fnd) {
+  struct mg_connection *c = NULL;
+  if (url == NULL) url = "udp://time.google.com:123";
+  if ((c = mg_connect(mgr, url, fn, fnd)) != NULL) c->pfn = sntp_cb;
+  return c;
+}
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/sock.c"
+#endif
+
+
+
+
+
+
+
+
+
+
+
+#if MG_ENABLE_SOCKET
+
+#ifndef closesocket
+#define closesocket(x) close(x)
+#endif
+
+#define FD(c_) ((MG_SOCKET_TYPE) (size_t) (c_)->fd)
+#define S2PTR(s_) ((void *) (size_t) (s_))
+
+#ifndef MSG_NONBLOCKING
+#define MSG_NONBLOCKING 0
+#endif
+
+#ifndef AF_INET6
+#define AF_INET6 10
+#endif
+
+#ifndef MG_SOCK_ERR
+#define MG_SOCK_ERR(errcode) ((errcode) < 0 ? errno : 0)
+#endif
+
+#ifndef MG_SOCK_INTR
+#define MG_SOCK_INTR(fd) (fd == MG_INVALID_SOCKET && MG_SOCK_ERR(-1) == EINTR)
+#endif
+
+#ifndef MG_SOCK_PENDING
+#define MG_SOCK_PENDING(errcode) \
+  (((errcode) < 0) && (errno == EINPROGRESS || errno == EWOULDBLOCK))
+#endif
+
+#ifndef MG_SOCK_RESET
+#define MG_SOCK_RESET(errcode) \
+  (((errcode) < 0) && (errno == EPIPE || errno == ECONNRESET))
+#endif
+
+union usa {
+  struct sockaddr sa;
+  struct sockaddr_in sin;
+#if MG_ENABLE_IPV6
+  struct sockaddr_in6 sin6;
+#endif
+};
+
+static socklen_t tousa(struct mg_addr *a, union usa *usa) {
+  socklen_t len = sizeof(usa->sin);
+  memset(usa, 0, sizeof(*usa));
+  usa->sin.sin_family = AF_INET;
+  usa->sin.sin_port = a->port;
+  memcpy(&usa->sin.sin_addr, a->ip, sizeof(uint32_t));
+#if MG_ENABLE_IPV6
+  if (a->is_ip6) {
+    usa->sin.sin_family = AF_INET6;
+    usa->sin6.sin6_port = a->port;
+    usa->sin6.sin6_scope_id = a->scope_id;
+    memcpy(&usa->sin6.sin6_addr, a->ip, sizeof(a->ip));
+    len = sizeof(usa->sin6);
+  }
+#endif
+  return len;
+}
+
+static void tomgaddr(union usa *usa, struct mg_addr *a, bool is_ip6) {
+  a->is_ip6 = is_ip6;
+  a->port = usa->sin.sin_port;
+  memcpy(&a->ip, &usa->sin.sin_addr, sizeof(uint32_t));
+#if MG_ENABLE_IPV6
+  if (is_ip6) {
+    memcpy(a->ip, &usa->sin6.sin6_addr, sizeof(a->ip));
+    a->port = usa->sin6.sin6_port;
+    a->scope_id = (uint8_t) usa->sin6.sin6_scope_id;
+  }
+#endif
+}
+
+static void setlocaddr(MG_SOCKET_TYPE fd, struct mg_addr *addr) {
+  union usa usa;
+  socklen_t n = sizeof(usa);
+  if (getsockname(fd, &usa.sa, &n) == 0) {
+    tomgaddr(&usa, addr, n != sizeof(usa.sin));
+  }
+}
+
+static void iolog(struct mg_connection *c, char *buf, long n, bool r) {
+  if (n == MG_IO_WAIT) {
+    // Do nothing
+  } else if (n <= 0) {
+    c->is_closing = 1;  // Termination. Don't call mg_error(): #1529
+  } else if (n > 0) {
+    if (c->is_hexdumping) {
+      MG_INFO(("\n-- %lu %M %s %M %ld", c->id, mg_print_ip_port, &c->loc,
+               r ? "<-" : "->", mg_print_ip_port, &c->rem, n));
+      mg_hexdump(buf, (size_t) n);
+    }
+    if (r) {
+      c->recv.len += (size_t) n;
+      mg_call(c, MG_EV_READ, &n);
+    } else {
+      mg_iobuf_del(&c->send, 0, (size_t) n);
+      // if (c->send.len == 0) mg_iobuf_resize(&c->send, 0);
+      if (c->send.len == 0) {
+        MG_EPOLL_MOD(c, 0);
+      }
+      mg_call(c, MG_EV_WRITE, &n);
     }
   }
-  return flags;
 }
 
-static int uri_to_path(struct mg_connection *c, struct mg_http_message *hm,
-                       const struct mg_http_serve_opts *opts, char *path,
-                       size_t path_size) {
-  struct mg_fs *fs = opts->fs == NULL ? &mg_fs_posix : opts->fs;
-  struct mg_str k, v, s = mg_str(opts->root_dir), u = {0, 0}, p = {0, 0};
-  while (mg_commalist(&s, &k, &v)) {
-    if (v.len == 0) v = k, k = mg_str("/");
-    if (hm->uri.len < k.len) continue;
-    if (mg_strcmp(k, mg_str_n(hm->uri.ptr, k.len)) != 0) continue;
-    u = k, p = v;
+long mg_io_send(struct mg_connection *c, const void *buf, size_t len) {
+  long n;
+  if (c->is_udp) {
+    union usa usa;
+    socklen_t slen = tousa(&c->rem, &usa);
+    n = sendto(FD(c), (char *) buf, len, 0, &usa.sa, slen);
+    if (n > 0) setlocaddr(FD(c), &c->loc);
+  } else {
+    n = send(FD(c), (char *) buf, len, MSG_NONBLOCKING);
   }
-  return uri_to_path2(c, hm, fs, u, p, path, path_size);
+  MG_VERBOSE(("%lu %ld %d", c->id, n, MG_SOCK_ERR(n)));
+  if (MG_SOCK_PENDING(n)) return MG_IO_WAIT;
+  if (MG_SOCK_RESET(n)) return MG_IO_RESET;
+  if (n <= 0) return MG_IO_ERR;
+  return n;
 }
 
-void mg_http_serve_dir(struct mg_connection *c, struct mg_http_message *hm,
-                       const struct mg_http_serve_opts *opts) {
-  char path[MG_PATH_MAX];
-  const char *sp = opts->ssi_pattern;
-  int flags = uri_to_path(c, hm, opts, path, sizeof(path));
-  if (flags < 0) {
-    // Do nothing: the response has already been sent by uri_to_path()
-  } else if (flags & MG_FS_DIR) {
-    listdir(c, hm, opts, path);
-  } else if (flags && sp != NULL &&
-             mg_globmatch(sp, strlen(sp), path, strlen(path))) {
-    mg_http_serve_ssi(c, opts->root_dir, path);
+bool mg_send(struct mg_connection *c, const void *buf, size_t len) {
+  if (c->is_udp) {
+    long n = mg_io_send(c, buf, len);
+    MG_DEBUG(("%lu %ld %lu:%lu:%lu %ld err %d", c->id, c->fd, c->send.len,
+              c->recv.len, c->rtls.len, n, MG_SOCK_ERR(n)));
+    iolog(c, (char *) buf, n, false);
+    return n > 0;
   } else {
-    mg_http_serve_file(c, hm, path, opts);
+    return mg_iobuf_add(&c->send, c->send.len, buf, len);
   }
 }
 
-static bool mg_is_url_safe(int c) {
-  return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'z') ||
-         (c >= 'A' && c <= 'Z') || c == '.' || c == '_' || c == '-' || c == '~';
+static void mg_set_non_blocking_mode(MG_SOCKET_TYPE fd) {
+#if defined(MG_CUSTOM_NONBLOCK)
+  MG_CUSTOM_NONBLOCK(fd);
+#elif MG_ARCH == MG_ARCH_WIN32 && MG_ENABLE_WINSOCK
+  unsigned long on = 1;
+  ioctlsocket(fd, FIONBIO, &on);
+#elif MG_ENABLE_RL
+  unsigned long on = 1;
+  ioctlsocket(fd, FIONBIO, &on);
+#elif MG_ENABLE_FREERTOS_TCP
+  const BaseType_t off = 0;
+  if (setsockopt(fd, 0, FREERTOS_SO_RCVTIMEO, &off, sizeof(off)) != 0) (void) 0;
+  if (setsockopt(fd, 0, FREERTOS_SO_SNDTIMEO, &off, sizeof(off)) != 0) (void) 0;
+#elif MG_ENABLE_LWIP
+  lwip_fcntl(fd, F_SETFL, O_NONBLOCK);
+#elif MG_ARCH == MG_ARCH_AZURERTOS
+  fcntl(fd, F_SETFL, O_NONBLOCK);
+#elif MG_ARCH == MG_ARCH_TIRTOS
+  int val = 0;
+  setsockopt(fd, SOL_SOCKET, SO_BLOCKING, &val, sizeof(val));
+  // SPRU524J section 3.3.3 page 63, SO_SNDLOWAT
+  int sz = sizeof(val);
+  getsockopt(fd, SOL_SOCKET, SO_SNDBUF, &val, &sz);
+  val /= 2;  // set send low-water mark at half send buffer size
+  setsockopt(fd, SOL_SOCKET, SO_SNDLOWAT, &val, sizeof(val));
+#else
+  fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK);  // Non-blocking mode
+  fcntl(fd, F_SETFD, FD_CLOEXEC);                          // Set close-on-exec
+#endif
 }
 
-size_t mg_url_encode(const char *s, size_t sl, char *buf, size_t len) {
-  size_t i, n = 0;
-  for (i = 0; i < sl; i++) {
-    int c = *(unsigned char *) &s[i];
-    if (n + 4 >= len) return 0;
-    if (mg_is_url_safe(c)) {
-      buf[n++] = s[i];
+bool mg_open_listener(struct mg_connection *c, const char *url) {
+  MG_SOCKET_TYPE fd = MG_INVALID_SOCKET;
+  bool success = false;
+  c->loc.port = mg_htons(mg_url_port(url));
+  if (!mg_aton(mg_url_host(url), &c->loc)) {
+    MG_ERROR(("invalid listening URL: %s", url));
+  } else {
+    union usa usa;
+    socklen_t slen = tousa(&c->loc, &usa);
+    int rc, on = 1, af = c->loc.is_ip6 ? AF_INET6 : AF_INET;
+    int type = strncmp(url, "udp:", 4) == 0 ? SOCK_DGRAM : SOCK_STREAM;
+    int proto = type == SOCK_DGRAM ? IPPROTO_UDP : IPPROTO_TCP;
+    (void) on;
+
+    if ((fd = socket(af, type, proto)) == MG_INVALID_SOCKET) {
+      MG_ERROR(("socket: %d", MG_SOCK_ERR(-1)));
+#if defined(SO_EXCLUSIVEADDRUSE)
+    } else if ((rc = setsockopt(fd, SOL_SOCKET, SO_EXCLUSIVEADDRUSE,
+                                (char *) &on, sizeof(on))) != 0) {
+      // "Using SO_REUSEADDR and SO_EXCLUSIVEADDRUSE"
+      MG_ERROR(("setsockopt(SO_EXCLUSIVEADDRUSE): %d %d", on, MG_SOCK_ERR(rc)));
+#elif defined(SO_REUSEADDR) && (!defined(LWIP_SOCKET) || SO_REUSE)
+    } else if ((rc = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *) &on,
+                                sizeof(on))) != 0) {
+      // 1. SO_REUSEADDR semantics on UNIX and Windows is different.  On
+      // Windows, SO_REUSEADDR allows to bind a socket to a port without error
+      // even if the port is already open by another program. This is not the
+      // behavior SO_REUSEADDR was designed for, and leads to hard-to-track
+      // failure scenarios.
+      //
+      // 2. For LWIP, SO_REUSEADDR should be explicitly enabled by defining
+      // SO_REUSE = 1 in lwipopts.h, otherwise the code below will compile but
+      // won't work! (setsockopt will return EINVAL)
+      MG_ERROR(("setsockopt(SO_REUSEADDR): %d", MG_SOCK_ERR(rc)));
+#endif
+#if MG_IPV6_V6ONLY
+      // Bind only to the V6 address, not V4 address on this port
+    } else if (c->loc.is_ip6 &&
+               (rc = setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, (char *) &on,
+                                sizeof(on))) != 0) {
+      // See #2089. Allow to bind v4 and v6 sockets on the same port
+      MG_ERROR(("setsockopt(IPV6_V6ONLY): %d", MG_SOCK_ERR(rc)));
+#endif
+    } else if ((rc = bind(fd, &usa.sa, slen)) != 0) {
+      MG_ERROR(("bind: %d", MG_SOCK_ERR(rc)));
+    } else if ((type == SOCK_STREAM &&
+                (rc = listen(fd, MG_SOCK_LISTEN_BACKLOG_SIZE)) != 0)) {
+      // NOTE(lsm): FreeRTOS uses backlog value as a connection limit
+      // In case port was set to 0, get the real port number
+      MG_ERROR(("listen: %d", MG_SOCK_ERR(rc)));
     } else {
-      buf[n++] = '%';
-      mg_hex(&s[i], 1, &buf[n]);
-      n += 2;
+      setlocaddr(fd, &c->loc);
+      mg_set_non_blocking_mode(fd);
+      c->fd = S2PTR(fd);
+      MG_EPOLL_ADD(c);
+      success = true;
     }
   }
-  if (len > 0 && n < len - 1) buf[n] = '\0';  // Null-terminate the destination
-  if (len > 0) buf[len - 1] = '\0';           // Always.
-  return n;
+  if (success == false && fd != MG_INVALID_SOCKET) closesocket(fd);
+  return success;
 }
 
-void mg_http_creds(struct mg_http_message *hm, char *user, size_t userlen,
-                   char *pass, size_t passlen) {
-  struct mg_str *v = mg_http_get_header(hm, "Authorization");
-  user[0] = pass[0] = '\0';
-  if (v != NULL && v->len > 6 && memcmp(v->ptr, "Basic ", 6) == 0) {
-    char buf[256];
-    int n = mg_base64_decode(v->ptr + 6, (int) v->len - 6, buf);
-    const char *p = (const char *) memchr(buf, ':', n > 0 ? (size_t) n : 0);
-    if (p != NULL) {
-      mg_snprintf(user, userlen, "%.*s", (int) (p - buf), buf);
-      mg_snprintf(pass, passlen, "%.*s", n - (int) (p - buf) - 1, p + 1);
-    }
-  } else if (v != NULL && v->len > 7 && memcmp(v->ptr, "Bearer ", 7) == 0) {
-    mg_snprintf(pass, passlen, "%.*s", (int) v->len - 7, v->ptr + 7);
-  } else if ((v = mg_http_get_header(hm, "Cookie")) != NULL) {
-    struct mg_str t = mg_http_get_header_var(*v, mg_str_n("access_token", 12));
-    if (t.len > 0) mg_snprintf(pass, passlen, "%.*s", (int) t.len, t.ptr);
+static long recv_raw(struct mg_connection *c, void *buf, size_t len) {
+  long n = 0;
+  if (c->is_udp) {
+    union usa usa;
+    socklen_t slen = tousa(&c->rem, &usa);
+    n = recvfrom(FD(c), (char *) buf, len, 0, &usa.sa, &slen);
+    if (n > 0) tomgaddr(&usa, &c->rem, slen != sizeof(usa.sin));
   } else {
-    mg_http_get_var(&hm->query, "access_token", pass, passlen);
+    n = recv(FD(c), (char *) buf, len, MSG_NONBLOCKING);
   }
+  MG_VERBOSE(("%lu %ld %d", c->id, n, MG_SOCK_ERR(n)));
+  if (MG_SOCK_PENDING(n)) return MG_IO_WAIT;
+  if (MG_SOCK_RESET(n)) return MG_IO_RESET;
+  if (n <= 0) return MG_IO_ERR;
+  return n;
 }
 
-static struct mg_str stripquotes(struct mg_str s) {
-  return s.len > 1 && s.ptr[0] == '"' && s.ptr[s.len - 1] == '"'
-             ? mg_str_n(s.ptr + 1, s.len - 2)
-             : s;
+static bool ioalloc(struct mg_connection *c, struct mg_iobuf *io) {
+  bool res = false;
+  if (io->len >= MG_MAX_RECV_SIZE) {
+    mg_error(c, "MG_MAX_RECV_SIZE");
+  } else if (io->size <= io->len &&
+             !mg_iobuf_resize(io, io->size + MG_IO_SIZE)) {
+    mg_error(c, "OOM");
+  } else {
+    res = true;
+  }
+  return res;
 }
 
-struct mg_str mg_http_get_header_var(struct mg_str s, struct mg_str v) {
-  size_t i;
-  for (i = 0; v.len > 0 && i + v.len + 2 < s.len; i++) {
-    if (s.ptr[i + v.len] == '=' && memcmp(&s.ptr[i], v.ptr, v.len) == 0) {
-      const char *p = &s.ptr[i + v.len + 1], *b = p, *x = &s.ptr[s.len];
-      int q = p < x && *p == '"' ? 1 : 0;
-      while (p < x &&
-             (q ? p == b || *p != '"' : *p != ';' && *p != ' ' && *p != ','))
-        p++;
-      // MG_INFO(("[%.*s] [%.*s] [%.*s]", (int) s.len, s.ptr, (int) v.len,
-      // v.ptr, (int) (p - b), b));
-      return stripquotes(mg_str_n(b, (size_t) (p - b + q)));
+// NOTE(lsm): do only one iteration of reads, cause some systems
+// (e.g. FreeRTOS stack) return 0 instead of -1/EWOULDBLOCK when no data
+static void read_conn(struct mg_connection *c) {
+  if (ioalloc(c, &c->recv)) {
+    char *buf = (char *) &c->recv.buf[c->recv.len];
+    size_t len = c->recv.size - c->recv.len;
+    long n = -1;
+    if (c->is_tls) {
+      if (!ioalloc(c, &c->rtls)) return;
+      n = recv_raw(c, (char *) &c->rtls.buf[c->rtls.len],
+                   c->rtls.size - c->rtls.len);
+      if (n == MG_IO_ERR && c->rtls.len == 0) {
+        // Close only if we have fully drained both raw (rtls) and TLS buffers
+        c->is_closing = 1;
+      } else {
+        if (n > 0) c->rtls.len += (size_t) n;
+        if (c->is_tls_hs) mg_tls_handshake(c);
+        n = c->is_tls_hs ? (long) MG_IO_WAIT : mg_tls_recv(c, buf, len);
+      }
+    } else {
+      n = recv_raw(c, buf, len);
     }
+    MG_DEBUG(("%lu %ld %lu:%lu:%lu %ld err %d", c->id, c->fd, c->send.len,
+              c->recv.len, c->rtls.len, n, MG_SOCK_ERR(n)));
+    iolog(c, buf, n, true);
   }
-  return mg_str_n(NULL, 0);
 }
 
-bool mg_http_match_uri(const struct mg_http_message *hm, const char *glob) {
-  return mg_match(hm->uri, mg_str(glob), NULL);
+static void write_conn(struct mg_connection *c) {
+  char *buf = (char *) c->send.buf;
+  size_t len = c->send.len;
+  long n = c->is_tls ? mg_tls_send(c, buf, len) : mg_io_send(c, buf, len);
+  MG_DEBUG(("%lu %ld snd %ld/%ld rcv %ld/%ld n=%ld err=%d", c->id, c->fd,
+            (long) c->send.len, (long) c->send.size, (long) c->recv.len,
+            (long) c->recv.size, n, MG_SOCK_ERR(n)));
+  iolog(c, buf, n, false);
 }
 
-long mg_http_upload(struct mg_connection *c, struct mg_http_message *hm,
-                    struct mg_fs *fs, const char *path, size_t max_size) {
-  char buf[20] = "0";
-  long res = 0, offset;
-  mg_http_get_var(&hm->query, "offset", buf, sizeof(buf));
-  offset = strtol(buf, NULL, 0);
-  if (hm->body.len == 0) {
-    mg_http_reply(c, 200, "", "%ld", res);  // Nothing to write
+static void close_conn(struct mg_connection *c) {
+  if (FD(c) != MG_INVALID_SOCKET) {
+#if MG_ENABLE_EPOLL
+    epoll_ctl(c->mgr->epoll_fd, EPOLL_CTL_DEL, FD(c), NULL);
+#endif
+    closesocket(FD(c));
+#if MG_ENABLE_FREERTOS_TCP
+    FreeRTOS_FD_CLR(c->fd, c->mgr->ss, eSELECT_ALL);
+#endif
+  }
+  mg_close_conn(c);
+}
+
+static void connect_conn(struct mg_connection *c) {
+  union usa usa;
+  socklen_t n = sizeof(usa);
+  // Use getpeername() to test whether we have connected
+  if (getpeername(FD(c), &usa.sa, &n) == 0) {
+    c->is_connecting = 0;
+    setlocaddr(FD(c), &c->loc);
+    mg_call(c, MG_EV_CONNECT, NULL);
+    MG_EPOLL_MOD(c, 0);
+    if (c->is_tls_hs) mg_tls_handshake(c);
   } else {
-    struct mg_fd *fd;
-    size_t current_size = 0;
-    MG_DEBUG(("%s -> %d bytes @ %ld", path, (int) hm->body.len, offset));
-    if (offset == 0) fs->rm(path);  // If offset if 0, truncate file
-    fs->st(path, &current_size, NULL);
-    if (offset < 0) {
-      mg_http_reply(c, 400, "", "offset required");
-      res = -1;
-    } else if (offset > 0 && current_size != (size_t) offset) {
-      mg_http_reply(c, 400, "", "%s: offset mismatch", path);
-      res = -2;
-    } else if ((size_t) offset + hm->body.len > max_size) {
-      mg_http_reply(c, 400, "", "%s: over max size of %lu", path,
-                    (unsigned long) max_size);
-      res = -3;
-    } else if ((fd = mg_fs_open(fs, path, MG_FS_WRITE)) == NULL) {
-      mg_http_reply(c, 400, "", "open(%s): %d", path, errno);
-      res = -4;
+    mg_error(c, "socket error");
+  }
+}
+
+static void setsockopts(struct mg_connection *c) {
+#if MG_ENABLE_FREERTOS_TCP || MG_ARCH == MG_ARCH_AZURERTOS || \
+    MG_ARCH == MG_ARCH_TIRTOS
+  (void) c;
+#else
+  int on = 1;
+#if !defined(SOL_TCP)
+#define SOL_TCP IPPROTO_TCP
+#endif
+  if (setsockopt(FD(c), SOL_TCP, TCP_NODELAY, (char *) &on, sizeof(on)) != 0)
+    (void) 0;
+  if (setsockopt(FD(c), SOL_SOCKET, SO_KEEPALIVE, (char *) &on, sizeof(on)) !=
+      0)
+    (void) 0;
+#endif
+}
+
+void mg_connect_resolved(struct mg_connection *c) {
+  int type = c->is_udp ? SOCK_DGRAM : SOCK_STREAM;
+  int rc, af = c->rem.is_ip6 ? AF_INET6 : AF_INET;  // c->rem has resolved IP
+  c->fd = S2PTR(socket(af, type, 0));               // Create outbound socket
+  c->is_resolving = 0;                              // Clear resolving flag
+  if (FD(c) == MG_INVALID_SOCKET) {
+    mg_error(c, "socket(): %d", MG_SOCK_ERR(-1));
+  } else if (c->is_udp) {
+    MG_EPOLL_ADD(c);
+#if MG_ARCH == MG_ARCH_TIRTOS
+    union usa usa;  // TI-RTOS NDK requires binding to receive on UDP sockets
+    socklen_t slen = tousa(&c->loc, &usa);
+    if ((rc = bind(c->fd, &usa.sa, slen)) != 0)
+      MG_ERROR(("bind: %d", MG_SOCK_ERR(rc)));
+#endif
+    setlocaddr(FD(c), &c->loc);
+    mg_call(c, MG_EV_RESOLVE, NULL);
+    mg_call(c, MG_EV_CONNECT, NULL);
+  } else {
+    union usa usa;
+    socklen_t slen = tousa(&c->rem, &usa);
+    mg_set_non_blocking_mode(FD(c));
+    setsockopts(c);
+    MG_EPOLL_ADD(c);
+    mg_call(c, MG_EV_RESOLVE, NULL);
+    rc = connect(FD(c), &usa.sa, slen);  // Attempt to connect
+    if (rc == 0) {                       // Success
+      setlocaddr(FD(c), &c->loc);
+      mg_call(c, MG_EV_CONNECT, NULL);  // Send MG_EV_CONNECT to the user
+    } else if (MG_SOCK_PENDING(rc)) {   // Need to wait for TCP handshake
+      MG_DEBUG(("%lu %ld -> %M pend", c->id, c->fd, mg_print_ip_port, &c->rem));
+      c->is_connecting = 1;
     } else {
-      res = offset + (long) fs->wr(fd->fd, hm->body.ptr, hm->body.len);
-      mg_fs_close(fd);
-      mg_http_reply(c, 200, "", "%ld", res);
+      mg_error(c, "connect: %d", MG_SOCK_ERR(rc));
     }
   }
-  return res;
-}
-
-int mg_http_status(const struct mg_http_message *hm) {
-  return atoi(hm->uri.ptr);
-}
-
-// If a server sends data to the client using chunked encoding, Mongoose strips
-// off the chunking prefix (hex length and \r\n) and suffix (\r\n), appends the
-// stripped data to the body, and fires the MG_EV_HTTP_CHUNK event.  When zero
-// chunk is received, we fire MG_EV_HTTP_MSG, and the body already has all
-// chunking prefixes/suffixes stripped.
-//
-// If a server sends data without chunked encoding, we also fire a series of
-// MG_EV_HTTP_CHUNK events for every received piece of data, and then we fire
-// MG_EV_HTTP_MSG event in the end.
-//
-// We track total processed length in the c->pfn_data, which is a void *
-// pointer: we store a size_t value there.
-static bool getchunk(struct mg_str s, size_t *prefixlen, size_t *datalen) {
-  size_t i = 0, n;
-  while (i < s.len && s.ptr[i] != '\r' && s.ptr[i] != '\n') i++;
-  n = mg_unhexn(s.ptr, i);
-  // MG_INFO(("%d %d", (int) (i + n + 4), (int) s.len));
-  if (s.len < i + n + 4) return false;  // Chunk not yet fully buffered
-  if (s.ptr[i] != '\r' || s.ptr[i + 1] != '\n') return false;
-  if (s.ptr[i + n + 2] != '\r' || s.ptr[i + n + 3] != '\n') return false;
-  *prefixlen = i + 2;
-  *datalen = n;
-  return true;
 }
 
-static bool mg_is_chunked(struct mg_http_message *hm) {
-  const char *needle = "chunked";
-  struct mg_str *te = mg_http_get_header(hm, "Transfer-Encoding");
-  return te != NULL && mg_vcasecmp(te, needle) == 0;
-}
-
-void mg_http_delete_chunk(struct mg_connection *c, struct mg_http_message *hm) {
-  size_t ofs = (size_t) (hm->chunk.ptr - (char *) c->recv.buf);
-  mg_iobuf_del(&c->recv, ofs, hm->chunk.len);
-  c->pfn_data = (void *) ((size_t) c->pfn_data | MG_DMARK);
-}
-
-static void deliver_chunked_chunks(struct mg_connection *c, size_t hlen,
-                                   struct mg_http_message *hm, bool *next) {
-  //  |  ... headers ... | HEXNUM\r\n ..data.. \r\n | ......
-  //  +------------------+--------------------------+----
-  //  |      hlen        |           chunk1         | ......
-  char *buf = (char *) &c->recv.buf[hlen], *p = buf;
-  size_t len = c->recv.len - hlen;
-  size_t processed = ((size_t) c->pfn_data) & ~MG_DMARK;
-  size_t mark, pl, dl, del = 0, ofs = 0;
-  bool last = false;
-  if (processed <= len) len -= processed, buf += processed;
-  while (!last && getchunk(mg_str_n(buf + ofs, len - ofs), &pl, &dl)) {
-    size_t saved = c->recv.len;
-    memmove(p + processed, buf + ofs + pl, dl);
-    // MG_INFO(("P2 [%.*s]", (int) (processed + dl), p));
-    hm->chunk = mg_str_n(p + processed, dl);
-    mg_call(c, MG_EV_HTTP_CHUNK, hm);
-    ofs += pl + dl + 2, del += pl + 2;  // 2 is for \r\n suffix
-    processed += dl;
-    if (c->recv.len != saved) processed -= dl, buf -= dl;
-    // mg_hexdump(c->recv.buf, hlen + processed);
-    last = (dl == 0);
-  }
-  mg_iobuf_del(&c->recv, hlen + processed, del);
-  mark = ((size_t) c->pfn_data) & MG_DMARK;
-  c->pfn_data = (void *) (processed | mark);
-  if (last) {
-    hm->body.len = processed;
-    hm->message.len = hlen + processed;
-    c->pfn_data = NULL;
-    if (mark) mg_iobuf_del(&c->recv, 0, hlen), *next = true;
-    // MG_INFO(("LAST, mark: %lx", mark));
-    // mg_hexdump(c->recv.buf, c->recv.len);
-  }
+static MG_SOCKET_TYPE raccept(MG_SOCKET_TYPE sock, union usa *usa,
+                              socklen_t *len) {
+  MG_SOCKET_TYPE fd = MG_INVALID_SOCKET;
+  do {
+    memset(usa, 0, sizeof(*usa));
+    fd = accept(sock, &usa->sa, len);
+  } while (MG_SOCK_INTR(fd));
+  return fd;
 }
 
-static void deliver_normal_chunks(struct mg_connection *c, size_t hlen,
-                                  struct mg_http_message *hm, bool *next) {
-  size_t left, processed = ((size_t) c->pfn_data) & ~MG_DMARK;
-  size_t deleted = ((size_t) c->pfn_data) & MG_DMARK;
-  hm->chunk = mg_str_n((char *) &c->recv.buf[hlen], c->recv.len - hlen);
-  if (processed <= hm->chunk.len && !deleted) {
-    hm->chunk.len -= processed;
-    hm->chunk.ptr += processed;
-  }
-  left = hm->body.len < processed ? 0 : hm->body.len - processed;
-  if (hm->chunk.len > left) hm->chunk.len = left;
-  if (hm->chunk.len > 0) mg_call(c, MG_EV_HTTP_CHUNK, hm);
-  processed += hm->chunk.len;
-  deleted = ((size_t) c->pfn_data) & MG_DMARK;  // Re-evaluate after user call
-  if (processed >= hm->body.len) {              // Last, 0-len chunk
-    hm->chunk.len = 0;                          // Reset length
-    mg_call(c, MG_EV_HTTP_CHUNK, hm);           // Call user handler
-    c->pfn_data = NULL;                         // Reset processed counter
-    if (processed && deleted) mg_iobuf_del(&c->recv, 0, hlen), *next = true;
+static void accept_conn(struct mg_mgr *mgr, struct mg_connection *lsn) {
+  struct mg_connection *c = NULL;
+  union usa usa;
+  socklen_t sa_len = sizeof(usa);
+  MG_SOCKET_TYPE fd = raccept(FD(lsn), &usa, &sa_len);
+  if (fd == MG_INVALID_SOCKET) {
+#if MG_ARCH == MG_ARCH_AZURERTOS || defined(__ECOS)
+    // AzureRTOS, in non-block socket mode can mark listening socket readable
+    // even it is not. See comment for 'select' func implementation in
+    // nx_bsd.c That's not an error, just should try later
+    if (errno != EAGAIN)
+#endif
+      MG_ERROR(("%lu accept failed, errno %d", lsn->id, MG_SOCK_ERR(-1)));
+#if (MG_ARCH != MG_ARCH_WIN32) && !MG_ENABLE_FREERTOS_TCP && \
+    (MG_ARCH != MG_ARCH_TIRTOS) && !MG_ENABLE_POLL && !MG_ENABLE_EPOLL
+  } else if ((long) fd >= FD_SETSIZE) {
+    MG_ERROR(("%ld > %ld", (long) fd, (long) FD_SETSIZE));
+    closesocket(fd);
+#endif
+  } else if ((c = mg_alloc_conn(mgr)) == NULL) {
+    MG_ERROR(("%lu OOM", lsn->id));
+    closesocket(fd);
   } else {
-    c->pfn_data = (void *) (processed | deleted);  // if it is set
+    tomgaddr(&usa, &c->rem, sa_len != sizeof(usa.sin));
+    LIST_ADD_HEAD(struct mg_connection, &mgr->conns, c);
+    c->fd = S2PTR(fd);
+    MG_EPOLL_ADD(c);
+    mg_set_non_blocking_mode(FD(c));
+    setsockopts(c);
+    c->is_accepted = 1;
+    c->is_hexdumping = lsn->is_hexdumping;
+    c->loc = lsn->loc;
+    c->pfn = lsn->pfn;
+    c->pfn_data = lsn->pfn_data;
+    c->fn = lsn->fn;
+    c->fn_data = lsn->fn_data;
+    MG_DEBUG(("%lu %ld accepted %M -> %M", c->id, c->fd, mg_print_ip_port,
+              &c->rem, mg_print_ip_port, &c->loc));
+    mg_call(c, MG_EV_OPEN, NULL);
+    mg_call(c, MG_EV_ACCEPT, NULL);
   }
 }
 
-static void http_cb(struct mg_connection *c, int ev, void *evd, void *fnd) {
-  if (ev == MG_EV_READ || ev == MG_EV_CLOSE) {
-    struct mg_http_message hm;
-    // mg_hexdump(c->recv.buf, c->recv.len);
-    while (c->recv.buf != NULL && c->recv.len > 0) {
-      bool next = false;
-      int hlen = mg_http_parse((char *) c->recv.buf, c->recv.len, &hm);
-      if (hlen < 0) {
-        mg_error(c, "HTTP parse:\n%.*s", (int) c->recv.len, c->recv.buf);
-        break;
-      }
-      if (c->is_resp) break;           // Response is still generated
-      if (hlen == 0) break;            // Request is not buffered yet
-      if (ev == MG_EV_CLOSE) {         // If client did not set Content-Length
-        hm.message.len = c->recv.len;  // and closes now, deliver a MSG
-        hm.body.len = hm.message.len - (size_t) (hm.body.ptr - hm.message.ptr);
-      }
-      if (mg_is_chunked(&hm)) {
-        deliver_chunked_chunks(c, (size_t) hlen, &hm, &next);
-      } else {
-        deliver_normal_chunks(c, (size_t) hlen, &hm, &next);
-      }
-      if (next) continue;  // Chunks & request were deleted
-      //  Chunk events are delivered. If we have full body, deliver MSG
-      if (c->recv.len < hm.message.len) break;
-      if (c->is_accepted) c->is_resp = 1;  // Start generating response
-      mg_call(c, MG_EV_HTTP_MSG, &hm);     // User handler can clear is_resp
-      mg_iobuf_del(&c->recv, 0, hm.message.len);
-    }
-  }
-  (void) evd, (void) fnd;
+static bool can_read(const struct mg_connection *c) {
+  return c->is_full == false;
 }
 
-struct mg_connection *mg_http_connect(struct mg_mgr *mgr, const char *url,
-                                      mg_event_handler_t fn, void *fn_data) {
-  struct mg_connection *c = mg_connect(mgr, url, fn, fn_data);
-  if (c != NULL) c->pfn = http_cb;
-  return c;
+static bool can_write(const struct mg_connection *c) {
+  return c->is_connecting || (c->send.len > 0 && c->is_tls_hs == 0);
 }
 
-struct mg_connection *mg_http_listen(struct mg_mgr *mgr, const char *url,
-                                     mg_event_handler_t fn, void *fn_data) {
-  struct mg_connection *c = mg_listen(mgr, url, fn, fn_data);
-  if (c != NULL) c->pfn = http_cb;
-  return c;
+static bool skip_iotest(const struct mg_connection *c) {
+  return (c->is_closing || c->is_resolving || FD(c) == MG_INVALID_SOCKET) ||
+         (can_read(c) == false && can_write(c) == false);
 }
 
-#ifdef MG_ENABLE_LINES
-#line 1 "src/iobuf.c"
-#endif
-
-
-
-
-// Not using memset for zeroing memory, cause it can be dropped by compiler
-// See https://github.com/cesanta/mongoose/pull/1265
-static void zeromem(volatile unsigned char *buf, size_t len) {
-  if (buf != NULL) {
-    while (len--) *buf++ = 0;
+static void mg_iotest(struct mg_mgr *mgr, int ms) {
+#if MG_ENABLE_FREERTOS_TCP
+  struct mg_connection *c;
+  for (c = mgr->conns; c != NULL; c = c->next) {
+    c->is_readable = c->is_writable = 0;
+    if (skip_iotest(c)) continue;
+    if (can_read(c))
+      FreeRTOS_FD_SET(c->fd, mgr->ss, eSELECT_READ | eSELECT_EXCEPT);
+    if (can_write(c)) FreeRTOS_FD_SET(c->fd, mgr->ss, eSELECT_WRITE);
+    if (c->is_closing) ms = 1;
   }
-}
-
-static size_t roundup(size_t size, size_t align) {
-  return align == 0 ? size : (size + align - 1) / align * align;
-}
-
-int mg_iobuf_resize(struct mg_iobuf *io, size_t new_size) {
-  int ok = 1;
-  new_size = roundup(new_size, io->align);
-  if (new_size == 0) {
-    zeromem(io->buf, io->size);
-    free(io->buf);
-    io->buf = NULL;
-    io->len = io->size = 0;
-  } else if (new_size != io->size) {
-    // NOTE(lsm): do not use realloc here. Use calloc/free only, to ease the
-    // porting to some obscure platforms like FreeRTOS
-    void *p = calloc(1, new_size);
-    if (p != NULL) {
-      size_t len = new_size < io->len ? new_size : io->len;
-      if (len > 0 && io->buf != NULL) memmove(p, io->buf, len);
-      zeromem(io->buf, io->size);
-      free(io->buf);
-      io->buf = (unsigned char *) p;
-      io->size = new_size;
+  FreeRTOS_select(mgr->ss, pdMS_TO_TICKS(ms));
+  for (c = mgr->conns; c != NULL; c = c->next) {
+    EventBits_t bits = FreeRTOS_FD_ISSET(c->fd, mgr->ss);
+    c->is_readable = bits & (eSELECT_READ | eSELECT_EXCEPT) ? 1U : 0;
+    c->is_writable = bits & eSELECT_WRITE ? 1U : 0;
+    if (c->fd != MG_INVALID_SOCKET)
+      FreeRTOS_FD_CLR(c->fd, mgr->ss,
+                      eSELECT_READ | eSELECT_EXCEPT | eSELECT_WRITE);
+  }
+#elif MG_ENABLE_EPOLL
+  size_t max = 1;
+  for (struct mg_connection *c = mgr->conns; c != NULL; c = c->next) {
+    c->is_readable = c->is_writable = 0;
+    if (c->rtls.len > 0 || mg_tls_pending(c) > 0) ms = 1, c->is_readable = 1;
+    if (can_write(c)) MG_EPOLL_MOD(c, 1);
+    if (c->is_closing) ms = 1;
+    max++;
+  }
+  struct epoll_event *evs = (struct epoll_event *) alloca(max * sizeof(evs[0]));
+  int n = epoll_wait(mgr->epoll_fd, evs, (int) max, ms);
+  for (int i = 0; i < n; i++) {
+    struct mg_connection *c = (struct mg_connection *) evs[i].data.ptr;
+    if (evs[i].events & EPOLLERR) {
+      mg_error(c, "socket error");
+    } else if (c->is_readable == 0) {
+      bool rd = evs[i].events & (EPOLLIN | EPOLLHUP);
+      bool wr = evs[i].events & EPOLLOUT;
+      c->is_readable = can_read(c) && rd ? 1U : 0;
+      c->is_writable = can_write(c) && wr ? 1U : 0;
+      if (c->rtls.len > 0 || mg_tls_pending(c) > 0) c->is_readable = 1;
+    }
+  }
+  (void) skip_iotest;
+#elif MG_ENABLE_POLL
+  nfds_t n = 0;
+  for (struct mg_connection *c = mgr->conns; c != NULL; c = c->next) n++;
+  struct pollfd *fds = (struct pollfd *) alloca(n * sizeof(fds[0]));
+  memset(fds, 0, n * sizeof(fds[0]));
+  n = 0;
+  for (struct mg_connection *c = mgr->conns; c != NULL; c = c->next) {
+    c->is_readable = c->is_writable = 0;
+    if (skip_iotest(c)) {
+      // Socket not valid, ignore
+    } else if (c->rtls.len > 0 || mg_tls_pending(c) > 0) {
+      ms = 1;  // Don't wait if TLS is ready
     } else {
-      ok = 0;
-      MG_ERROR(("%lld->%lld", (uint64_t) io->size, (uint64_t) new_size));
+      fds[n].fd = FD(c);
+      if (can_read(c)) fds[n].events |= POLLIN;
+      if (can_write(c)) fds[n].events |= POLLOUT;
+      if (c->is_closing) ms = 1;
+      n++;
     }
   }
-  return ok;
-}
-
-int mg_iobuf_init(struct mg_iobuf *io, size_t size, size_t align) {
-  io->buf = NULL;
-  io->align = align;
-  io->size = io->len = 0;
-  return mg_iobuf_resize(io, size);
-}
 
-size_t mg_iobuf_add(struct mg_iobuf *io, size_t ofs, const void *buf,
-                    size_t len) {
-  size_t new_size = roundup(io->len + len, io->align);
-  mg_iobuf_resize(io, new_size);      // Attempt to resize
-  if (new_size != io->size) len = 0;  // Resize failure, append nothing
-  if (ofs < io->len) memmove(io->buf + ofs + len, io->buf + ofs, io->len - ofs);
-  if (buf != NULL) memmove(io->buf + ofs, buf, len);
-  if (ofs > io->len) io->len += ofs - io->len;
-  io->len += len;
-  return len;
-}
+  // MG_INFO(("poll n=%d ms=%d", (int) n, ms));
+  if (poll(fds, n, ms) < 0) {
+#if MG_ARCH == MG_ARCH_WIN32
+    if (n == 0) Sleep(ms);  // On Windows, poll fails if no sockets
+#endif
+    memset(fds, 0, n * sizeof(fds[0]));
+  }
+  n = 0;
+  for (struct mg_connection *c = mgr->conns; c != NULL; c = c->next) {
+    if (skip_iotest(c)) {
+      // Socket not valid, ignore
+    } else if (c->rtls.len > 0 || mg_tls_pending(c) > 0) {
+      c->is_readable = 1;
+    } else {
+      if (fds[n].revents & POLLERR) {
+        mg_error(c, "socket error");
+      } else {
+        c->is_readable =
+            (unsigned) (fds[n].revents & (POLLIN | POLLHUP) ? 1 : 0);
+        c->is_writable = (unsigned) (fds[n].revents & POLLOUT ? 1 : 0);
+        if (c->rtls.len > 0 || mg_tls_pending(c) > 0) c->is_readable = 1;
+      }
+      n++;
+    }
+  }
+#else
+  struct timeval tv = {ms / 1000, (ms % 1000) * 1000}, tv_zero = {0, 0}, *tvp;
+  struct mg_connection *c;
+  fd_set rset, wset, eset;
+  MG_SOCKET_TYPE maxfd = 0;
+  int rc;
 
-size_t mg_iobuf_del(struct mg_iobuf *io, size_t ofs, size_t len) {
-  if (ofs > io->len) ofs = io->len;
-  if (ofs + len > io->len) len = io->len - ofs;
-  if (io->buf) memmove(io->buf + ofs, io->buf + ofs + len, io->len - ofs - len);
-  if (io->buf) zeromem(io->buf + io->len - len, len);
-  io->len -= len;
-  return len;
-}
+  FD_ZERO(&rset);
+  FD_ZERO(&wset);
+  FD_ZERO(&eset);
+  tvp = ms < 0 ? NULL : &tv;
+  for (c = mgr->conns; c != NULL; c = c->next) {
+    c->is_readable = c->is_writable = 0;
+    if (skip_iotest(c)) continue;
+    FD_SET(FD(c), &eset);
+    if (can_read(c)) FD_SET(FD(c), &rset);
+    if (can_write(c)) FD_SET(FD(c), &wset);
+    if (c->rtls.len > 0 || mg_tls_pending(c) > 0) tvp = &tv_zero;
+    if (FD(c) > maxfd) maxfd = FD(c);
+    if (c->is_closing) ms = 1;
+  }
 
-void mg_iobuf_free(struct mg_iobuf *io) {
-  mg_iobuf_resize(io, 0);
-}
+  if ((rc = select((int) maxfd + 1, &rset, &wset, &eset, tvp)) < 0) {
+#if MG_ARCH == MG_ARCH_WIN32
+    if (maxfd == 0) Sleep(ms);  // On Windows, select fails if no sockets
+#else
+    MG_ERROR(("select: %d %d", rc, MG_SOCK_ERR(rc)));
+#endif
+    FD_ZERO(&rset);
+    FD_ZERO(&wset);
+    FD_ZERO(&eset);
+  }
 
-#ifdef MG_ENABLE_LINES
-#line 1 "src/json.c"
+  for (c = mgr->conns; c != NULL; c = c->next) {
+    if (FD(c) != MG_INVALID_SOCKET && FD_ISSET(FD(c), &eset)) {
+      mg_error(c, "socket error");
+    } else {
+      c->is_readable = FD(c) != MG_INVALID_SOCKET && FD_ISSET(FD(c), &rset);
+      c->is_writable = FD(c) != MG_INVALID_SOCKET && FD_ISSET(FD(c), &wset);
+      if (c->rtls.len > 0 || mg_tls_pending(c) > 0) c->is_readable = 1;
+    }
+  }
 #endif
+}
 
+static bool mg_socketpair(MG_SOCKET_TYPE sp[2], union usa usa[2]) {
+  socklen_t n = sizeof(usa[0].sin);
+  bool success = false;
 
+  sp[0] = sp[1] = MG_INVALID_SOCKET;
+  (void) memset(&usa[0], 0, sizeof(usa[0]));
+  usa[0].sin.sin_family = AF_INET;
+  *(uint32_t *) &usa->sin.sin_addr = mg_htonl(0x7f000001U);  // 127.0.0.1
+  usa[1] = usa[0];
 
-
-static const char *escapeseq(int esc) {
-  return esc ? "\b\f\n\r\t\\\"" : "bfnrt\\\"";
+  if ((sp[0] = socket(AF_INET, SOCK_DGRAM, 0)) != MG_INVALID_SOCKET &&
+      (sp[1] = socket(AF_INET, SOCK_DGRAM, 0)) != MG_INVALID_SOCKET &&
+      bind(sp[0], &usa[0].sa, n) == 0 &&          //
+      bind(sp[1], &usa[1].sa, n) == 0 &&          //
+      getsockname(sp[0], &usa[0].sa, &n) == 0 &&  //
+      getsockname(sp[1], &usa[1].sa, &n) == 0 &&  //
+      connect(sp[0], &usa[1].sa, n) == 0 &&       //
+      connect(sp[1], &usa[0].sa, n) == 0) {       //
+    success = true;
+  }
+  if (!success) {
+    if (sp[0] != MG_INVALID_SOCKET) closesocket(sp[0]);
+    if (sp[1] != MG_INVALID_SOCKET) closesocket(sp[1]);
+    sp[0] = sp[1] = MG_INVALID_SOCKET;
+  }
+  return success;
 }
 
-static char json_esc(int c, int esc) {
-  const char *p, *esc1 = escapeseq(esc), *esc2 = escapeseq(!esc);
-  for (p = esc1; *p != '\0'; p++) {
-    if (*p == c) return esc2[p - esc1];
+// mg_wakeup() event handler
+static void wufn(struct mg_connection *c, int ev, void *ev_data) {
+  if (ev == MG_EV_READ) {
+    unsigned long *id = (unsigned long *) c->recv.buf;
+    // MG_INFO(("Got data"));
+    // mg_hexdump(c->recv.buf, c->recv.len);
+    if (c->recv.len >= sizeof(*id)) {
+      struct mg_connection *t;
+      for (t = c->mgr->conns; t != NULL; t = t->next) {
+        if (t->id == *id) {
+          struct mg_str data = mg_str_n((char *) c->recv.buf + sizeof(*id),
+                                        c->recv.len - sizeof(*id));
+          mg_call(t, MG_EV_WAKEUP, &data);
+        }
+      }
+    }
+    c->recv.len = 0;  // Consume received data
+  } else if (ev == MG_EV_CLOSE) {
+    closesocket(c->mgr->pipe);         // When we're closing, close the other
+    c->mgr->pipe = MG_INVALID_SOCKET;  // side of the socketpair, too
   }
-  return 0;
+  (void) ev_data;
 }
 
-static int mg_pass_string(const char *s, int len) {
-  int i;
-  for (i = 0; i < len; i++) {
-    if (s[i] == '\\' && i + 1 < len && json_esc(s[i + 1], 1)) {
-      i++;
-    } else if (s[i] == '\0') {
-      return MG_JSON_INVALID;
-    } else if (s[i] == '"') {
-      return i;
+bool mg_wakeup_init(struct mg_mgr *mgr) {
+  bool ok = false;
+  if (mgr->pipe == MG_INVALID_SOCKET) {
+    union usa usa[2];
+    MG_SOCKET_TYPE sp[2] = {MG_INVALID_SOCKET, MG_INVALID_SOCKET};
+    struct mg_connection *c = NULL;
+    if (!mg_socketpair(sp, usa)) {
+      MG_ERROR(("Cannot create socket pair"));
+    } else if ((c = mg_wrapfd(mgr, (int) sp[1], wufn, NULL)) == NULL) {
+      closesocket(sp[0]);
+      closesocket(sp[1]);
+      sp[0] = sp[1] = MG_INVALID_SOCKET;
+    } else {
+      tomgaddr(&usa[0], &c->rem, false);
+      MG_DEBUG(("%lu %p pipe %lu", c->id, c->fd, (unsigned long) sp[0]));
+      mgr->pipe = sp[0];
+      ok = true;
     }
   }
-  return MG_JSON_INVALID;
+  return ok;
 }
 
-static double mg_atod(const char *p, int len, int *numlen) {
-  double d = 0.0;
-  int i = 0, sign = 1;
-
-  // Sign
-  if (i < len && *p == '-') {
-    sign = -1, i++;
-  } else if (i < len && *p == '+') {
-    i++;
+bool mg_wakeup(struct mg_mgr *mgr, unsigned long conn_id, const void *buf,
+               size_t len) {
+  if (mgr->pipe != MG_INVALID_SOCKET && conn_id > 0) {
+    char *extended_buf = (char *) alloca(len + sizeof(conn_id));
+    memcpy(extended_buf, &conn_id, sizeof(conn_id));
+    memcpy(extended_buf + sizeof(conn_id), buf, len);
+    send(mgr->pipe, extended_buf, len + sizeof(conn_id), MSG_NONBLOCKING);
+    return true;
   }
+  return false;
+}
 
-  // Decimal
-  for (; i < len && p[i] >= '0' && p[i] <= '9'; i++) {
-    d *= 10.0;
-    d += p[i] - '0';
-  }
-  d *= sign;
+void mg_mgr_poll(struct mg_mgr *mgr, int ms) {
+  struct mg_connection *c, *tmp;
+  uint64_t now;
 
-  // Fractional
-  if (i < len && p[i] == '.') {
-    double frac = 0.0, base = 0.1;
-    i++;
-    for (; i < len && p[i] >= '0' && p[i] <= '9'; i++) {
-      frac += base * (p[i] - '0');
-      base /= 10.0;
+  mg_iotest(mgr, ms);
+  now = mg_millis();
+  mg_timer_poll(&mgr->timers, now);
+
+  for (c = mgr->conns; c != NULL; c = tmp) {
+    bool is_resp = c->is_resp;
+    tmp = c->next;
+    mg_call(c, MG_EV_POLL, &now);
+    if (is_resp && !c->is_resp) {
+      long n = 0;
+      mg_call(c, MG_EV_READ, &n);
+    }
+    MG_VERBOSE(("%lu %c%c %c%c%c%c%c %lu %lu", c->id,
+                c->is_readable ? 'r' : '-', c->is_writable ? 'w' : '-',
+                c->is_tls ? 'T' : 't', c->is_connecting ? 'C' : 'c',
+                c->is_tls_hs ? 'H' : 'h', c->is_resolving ? 'R' : 'r',
+                c->is_closing ? 'C' : 'c', mg_tls_pending(c), c->rtls.len));
+    if (c->is_resolving || c->is_closing) {
+      // Do nothing
+    } else if (c->is_listening && c->is_udp == 0) {
+      if (c->is_readable) accept_conn(mgr, c);
+    } else if (c->is_connecting) {
+      if (c->is_readable || c->is_writable) connect_conn(c);
+      //} else if (c->is_tls_hs) {
+      //  if ((c->is_readable || c->is_writable)) mg_tls_handshake(c);
+    } else {
+      if (c->is_readable) read_conn(c);
+      if (c->is_writable) write_conn(c);
     }
-    d += frac * sign;
-  }
 
-  // Exponential
-  if (i < len && (p[i] == 'e' || p[i] == 'E')) {
-    int j, exp = 0, minus = 0;
-    i++;
-    if (i < len && p[i] == '-') minus = 1, i++;
-    if (i < len && p[i] == '+') i++;
-    while (i < len && p[i] >= '0' && p[i] <= '9' && exp < 308)
-      exp = exp * 10 + (p[i++] - '0');
-    if (minus) exp = -exp;
-    for (j = 0; j < exp; j++) d *= 10.0;
-    for (j = 0; j < -exp; j++) d /= 10.0;
+    if (c->is_draining && c->send.len == 0) c->is_closing = 1;
+    if (c->is_closing) close_conn(c);
   }
-
-  if (numlen != NULL) *numlen = i;
-  return d;
 }
+#endif
 
-int mg_json_get(struct mg_str json, const char *path, int *toklen) {
-  const char *s = json.ptr;
-  int len = (int) json.len;
-  enum { S_VALUE, S_KEY, S_COLON, S_COMMA_OR_EOO } expecting = S_VALUE;
-  unsigned char nesting[MG_JSON_MAX_DEPTH];
-  int i = 0;             // Current offset in `s`
-  int j = 0;             // Offset in `s` we're looking for (return value)
-  int depth = 0;         // Current depth (nesting level)
-  int ed = 0;            // Expected depth
-  int pos = 1;           // Current position in `path`
-  int ci = -1, ei = -1;  // Current and expected index in array
+#ifdef MG_ENABLE_LINES
+#line 1 "src/ssi.c"
+#endif
 
-  if (toklen) *toklen = 0;
-  if (path[0] != '$') return MG_JSON_INVALID;
 
-#define MG_CHECKRET(x)                                  \
-  do {                                                  \
-    if (depth == ed && path[pos] == '\0' && ci == ei) { \
-      if (toklen) *toklen = i - j + 1;                  \
-      return j;                                         \
-    }                                                   \
-  } while (0)
 
-// In the ascii table, the distance between `[` and `]` is 2.
-// Ditto for `{` and `}`. Hence +2 in the code below.
-#define MG_EOO(x)                                            \
-  do {                                                       \
-    if (depth == ed && ci != ei) return MG_JSON_NOT_FOUND;   \
-    if (c != nesting[depth - 1] + 2) return MG_JSON_INVALID; \
-    depth--;                                                 \
-    MG_CHECKRET(x);                                          \
-  } while (0)
 
-  for (i = 0; i < len; i++) {
-    unsigned char c = ((unsigned char *) s)[i];
-    if (c == ' ' || c == '\t' || c == '\n' || c == '\r') continue;
-    switch (expecting) {
-      case S_VALUE:
-        // p("V %s [%.*s] %d %d %d %d\n", path, pos, path, depth, ed, ci, ei);
-        if (depth == ed) j = i;
-        if (c == '{') {
-          if (depth >= (int) sizeof(nesting)) return MG_JSON_TOO_DEEP;
-          if (depth == ed && path[pos] == '.' && ci == ei) {
-            // If we start the object, reset array indices
-            ed++, pos++, ci = ei = -1;
-          }
-          nesting[depth++] = c;
-          expecting = S_KEY;
-          break;
-        } else if (c == '[') {
-          if (depth >= (int) sizeof(nesting)) return MG_JSON_TOO_DEEP;
-          if (depth == ed && path[pos] == '[' && ei == ci) {
-            ed++, pos++, ci = 0;
-            for (ei = 0; path[pos] != ']' && path[pos] != '\0'; pos++) {
-              ei *= 10;
-              ei += path[pos] - '0';
-            }
-            if (path[pos] != 0) pos++;
-          }
-          nesting[depth++] = c;
-          break;
-        } else if (c == ']' && depth > 0) {  // Empty array
-          MG_EOO(']');
-        } else if (c == 't' && i + 3 < len && memcmp(&s[i], "true", 4) == 0) {
-          i += 3;
-        } else if (c == 'n' && i + 3 < len && memcmp(&s[i], "null", 4) == 0) {
-          i += 3;
-        } else if (c == 'f' && i + 4 < len && memcmp(&s[i], "false", 5) == 0) {
-          i += 4;
-        } else if (c == '-' || ((c >= '0' && c <= '9'))) {
-          int numlen = 0;
-          mg_atod(&s[i], len - i, &numlen);
-          i += numlen - 1;
-        } else if (c == '"') {
-          int n = mg_pass_string(&s[i + 1], len - i - 1);
-          if (n < 0) return n;
-          i += n + 1;
-        } else {
-          return MG_JSON_INVALID;
-        }
-        MG_CHECKRET('V');
-        if (depth == ed && ei >= 0) ci++;
-        expecting = S_COMMA_OR_EOO;
-        break;
+#ifndef MG_MAX_SSI_DEPTH
+#define MG_MAX_SSI_DEPTH 5
+#endif
 
-      case S_KEY:
-        if (c == '"') {
-          int n = mg_pass_string(&s[i + 1], len - i - 1);
-          if (n < 0) return n;
-          if (i + 1 + n >= len) return MG_JSON_NOT_FOUND;
-          if (depth < ed) return MG_JSON_NOT_FOUND;
-          if (depth == ed && path[pos - 1] != '.') return MG_JSON_NOT_FOUND;
-          // printf("K %s [%.*s] [%.*s] %d %d %d\n", path, pos, path, n,
-          //  &s[i + 1], n, depth, ed);
-          // NOTE(cpq): in the check sequence below is important.
-          // strncmp() must go first: it fails fast if the remaining length of
-          // the path is smaller than `n`.
-          if (depth == ed && path[pos - 1] == '.' &&
-              strncmp(&s[i + 1], &path[pos], (size_t) n) == 0 &&
-              (path[pos + n] == '\0' || path[pos + n] == '.' ||
-               path[pos + n] == '[')) {
-            pos += n;
-          }
-          i += n + 1;
-          expecting = S_COLON;
-        } else if (c == '}') {  // Empty object
-          MG_EOO('}');
-          expecting = S_COMMA_OR_EOO;
-        } else {
-          return MG_JSON_INVALID;
-        }
-        break;
+#ifndef MG_SSI_BUFSIZ
+#define MG_SSI_BUFSIZ 1024
+#endif
 
-      case S_COLON:
-        if (c == ':') {
-          expecting = S_VALUE;
+#if MG_ENABLE_SSI
+static char *mg_ssi(const char *path, const char *root, int depth) {
+  struct mg_iobuf b = {NULL, 0, 0, MG_IO_SIZE};
+  FILE *fp = fopen(path, "rb");
+  if (fp != NULL) {
+    char buf[MG_SSI_BUFSIZ], arg[sizeof(buf)];
+    int ch, intag = 0;
+    size_t len = 0;
+    buf[0] = arg[0] = '\0';
+    while ((ch = fgetc(fp)) != EOF) {
+      if (intag && ch == '>' && buf[len - 1] == '-' && buf[len - 2] == '-') {
+        buf[len++] = (char) (ch & 0xff);
+        buf[len] = '\0';
+        if (sscanf(buf, "<!--#include file=\"%[^\"]", arg)) {
+          char tmp[MG_PATH_MAX + MG_SSI_BUFSIZ + 10],
+              *p = (char *) path + strlen(path), *data;
+          while (p > path && p[-1] != MG_DIRSEP && p[-1] != '/') p--;
+          mg_snprintf(tmp, sizeof(tmp), "%.*s%s", (int) (p - path), path, arg);
+          if (depth < MG_MAX_SSI_DEPTH &&
+              (data = mg_ssi(tmp, root, depth + 1)) != NULL) {
+            mg_iobuf_add(&b, b.len, data, strlen(data));
+            free(data);
+          } else {
+            MG_ERROR(("%s: file=%s error or too deep", path, arg));
+          }
+        } else if (sscanf(buf, "<!--#include virtual=\"%[^\"]", arg)) {
+          char tmp[MG_PATH_MAX + MG_SSI_BUFSIZ + 10], *data;
+          mg_snprintf(tmp, sizeof(tmp), "%s%s", root, arg);
+          if (depth < MG_MAX_SSI_DEPTH &&
+              (data = mg_ssi(tmp, root, depth + 1)) != NULL) {
+            mg_iobuf_add(&b, b.len, data, strlen(data));
+            free(data);
+          } else {
+            MG_ERROR(("%s: virtual=%s error or too deep", path, arg));
+          }
         } else {
-          return MG_JSON_INVALID;
+          // Unknown SSI tag
+          MG_ERROR(("Unknown SSI tag: %.*s", (int) len, buf));
+          mg_iobuf_add(&b, b.len, buf, len);
         }
-        break;
-
-      case S_COMMA_OR_EOO:
-        if (depth <= 0) {
-          return MG_JSON_INVALID;
-        } else if (c == ',') {
-          expecting = (nesting[depth - 1] == '{') ? S_KEY : S_VALUE;
-        } else if (c == ']' || c == '}') {
-          MG_EOO('O');
-          if (depth == ed && ei >= 0) ci++;
-        } else {
-          return MG_JSON_INVALID;
+        intag = 0;
+        len = 0;
+      } else if (ch == '<') {
+        intag = 1;
+        if (len > 0) mg_iobuf_add(&b, b.len, buf, len);
+        len = 0;
+        buf[len++] = (char) (ch & 0xff);
+      } else if (intag) {
+        if (len == 5 && strncmp(buf, "<!--#", 5) != 0) {
+          intag = 0;
+        } else if (len >= sizeof(buf) - 2) {
+          MG_ERROR(("%s: SSI tag is too large", path));
+          len = 0;
         }
-        break;
+        buf[len++] = (char) (ch & 0xff);
+      } else {
+        buf[len++] = (char) (ch & 0xff);
+        if (len >= sizeof(buf)) {
+          mg_iobuf_add(&b, b.len, buf, len);
+          len = 0;
+        }
+      }
     }
+    if (len > 0) mg_iobuf_add(&b, b.len, buf, len);
+    if (b.len > 0) mg_iobuf_add(&b, b.len, "", 1);  // nul-terminate
+    fclose(fp);
   }
-  return MG_JSON_NOT_FOUND;
+  (void) depth;
+  (void) root;
+  return (char *) b.buf;
 }
 
-bool mg_json_get_num(struct mg_str json, const char *path, double *v) {
-  int n, toklen, found = 0;
-  if ((n = mg_json_get(json, path, &toklen)) >= 0 &&
-      (json.ptr[n] == '-' || (json.ptr[n] >= '0' && json.ptr[n] <= '9'))) {
-    if (v != NULL) *v = mg_atod(json.ptr + n, toklen, NULL);
-    found = 1;
-  }
-  return found;
+void mg_http_serve_ssi(struct mg_connection *c, const char *root,
+                       const char *fullpath) {
+  const char *headers = "Content-Type: text/html; charset=utf-8\r\n";
+  char *data = mg_ssi(fullpath, root, 0);
+  mg_http_reply(c, 200, headers, "%s", data == NULL ? "" : data);
+  free(data);
+}
+#else
+void mg_http_serve_ssi(struct mg_connection *c, const char *root,
+                       const char *fullpath) {
+  mg_http_reply(c, 501, NULL, "SSI not enabled");
+  (void) root, (void) fullpath;
 }
+#endif
 
-bool mg_json_get_bool(struct mg_str json, const char *path, bool *v) {
-  int found = 0, off = mg_json_get(json, path, NULL);
-  if (off >= 0 && (json.ptr[off] == 't' || json.ptr[off] == 'f')) {
-    if (v != NULL) *v = json.ptr[off] == 't';
-    found = 1;
-  }
-  return found;
+#ifdef MG_ENABLE_LINES
+#line 1 "src/str.c"
+#endif
+
+
+struct mg_str mg_str_s(const char *s) {
+  struct mg_str str = {(char *) s, s == NULL ? 0 : strlen(s)};
+  return str;
 }
 
-static bool json_unescape(const char *s, size_t len, char *to, size_t n) {
-  size_t i, j;
-  for (i = 0, j = 0; i < len && j < n; i++, j++) {
-    if (s[i] == '\\' && i + 5 < len && s[i + 1] == 'u') {
-      //  \uXXXX escape. We could process a simple one-byte chars
-      // \u00xx from the ASCII range. More complex chars would require
-      // dragging in a UTF8 library, which is too much for us
-      if (s[i + 2] != '0' || s[i + 3] != '0') return false;  // Give up
-      ((unsigned char *) to)[j] = (unsigned char) mg_unhexn(s + i + 4, 2);
+struct mg_str mg_str_n(const char *s, size_t n) {
+  struct mg_str str = {(char *) s, n};
+  return str;
+}
 
-      i += 5;
-    } else if (s[i] == '\\' && i + 1 < len) {
-      char c = json_esc(s[i + 1], 0);
-      if (c == 0) return false;
-      to[j] = c;
-      i++;
-    } else {
-      to[j] = s[i];
-    }
+static int mg_tolc(char c) {
+  return (c >= 'A' && c <= 'Z') ? c + 'a' - 'A' : c;
+}
+
+int mg_casecmp(const char *s1, const char *s2) {
+  int diff = 0;
+  do {
+    int c = mg_tolc(*s1++), d = mg_tolc(*s2++);
+    diff = c - d;
+  } while (diff == 0 && s1[-1] != '\0');
+  return diff;
+}
+
+int mg_strcmp(const struct mg_str str1, const struct mg_str str2) {
+  size_t i = 0;
+  while (i < str1.len && i < str2.len) {
+    int c1 = str1.buf[i];
+    int c2 = str2.buf[i];
+    if (c1 < c2) return -1;
+    if (c1 > c2) return 1;
+    i++;
   }
-  if (j >= n) return false;
-  if (n > 0) to[j] = '\0';
-  return true;
+  if (i < str1.len) return 1;
+  if (i < str2.len) return -1;
+  return 0;
 }
 
-char *mg_json_get_str(struct mg_str json, const char *path) {
-  char *result = NULL;
-  int len = 0, off = mg_json_get(json, path, &len);
-  if (off >= 0 && len > 1 && json.ptr[off] == '"') {
-    if ((result = (char *) calloc(1, (size_t) len)) != NULL &&
-        !json_unescape(json.ptr + off + 1, (size_t) (len - 2), result,
-                       (size_t) len)) {
-      free(result);
-      result = NULL;
-    }
+int mg_strcasecmp(const struct mg_str str1, const struct mg_str str2) {
+  size_t i = 0;
+  while (i < str1.len && i < str2.len) {
+    int c1 = mg_tolc(str1.buf[i]);
+    int c2 = mg_tolc(str2.buf[i]);
+    if (c1 < c2) return -1;
+    if (c1 > c2) return 1;
+    i++;
   }
-  return result;
+  if (i < str1.len) return 1;
+  if (i < str2.len) return -1;
+  return 0;
 }
 
-char *mg_json_get_b64(struct mg_str json, const char *path, int *slen) {
-  char *result = NULL;
-  int len = 0, off = mg_json_get(json, path, &len);
-  if (off >= 0 && json.ptr[off] == '"' && len > 1 &&
-      (result = (char *) calloc(1, (size_t) len)) != NULL) {
-    int k = mg_base64_decode(json.ptr + off + 1, len - 2, result);
-    if (slen != NULL) *slen = k;
+bool mg_match(struct mg_str s, struct mg_str p, struct mg_str *caps) {
+  size_t i = 0, j = 0, ni = 0, nj = 0;
+  if (caps) caps->buf = NULL, caps->len = 0;
+  while (i < p.len || j < s.len) {
+    if (i < p.len && j < s.len && (p.buf[i] == '?' || s.buf[j] == p.buf[i])) {
+      if (caps == NULL) {
+      } else if (p.buf[i] == '?') {
+        caps->buf = &s.buf[j], caps->len = 1;     // Finalize `?` cap
+        caps++, caps->buf = NULL, caps->len = 0;  // Init next cap
+      } else if (caps->buf != NULL && caps->len == 0) {
+        caps->len = (size_t) (&s.buf[j] - caps->buf);  // Finalize current cap
+        caps++, caps->len = 0, caps->buf = NULL;       // Init next cap
+      }
+      i++, j++;
+    } else if (i < p.len && (p.buf[i] == '*' || p.buf[i] == '#')) {
+      if (caps && !caps->buf) caps->len = 0, caps->buf = &s.buf[j];  // Init cap
+      ni = i++, nj = j + 1;
+    } else if (nj > 0 && nj <= s.len && (p.buf[ni] == '#' || s.buf[j] != '/')) {
+      i = ni, j = nj;
+      if (caps && caps->buf == NULL && caps->len == 0) {
+        caps--, caps->len = 0;  // Restart previous cap
+      }
+    } else {
+      return false;
+    }
   }
-  return result;
+  if (caps && caps->buf && caps->len == 0) {
+    caps->len = (size_t) (&s.buf[j] - caps->buf);
+  }
+  return true;
 }
 
-char *mg_json_get_hex(struct mg_str json, const char *path, int *slen) {
-  char *result = NULL;
-  int len = 0, off = mg_json_get(json, path, &len);
-  if (off >= 0 && json.ptr[off] == '"' && len > 1 &&
-      (result = (char *) calloc(1, (size_t) len / 2)) != NULL) {
-    mg_unhex(json.ptr + off + 1, (size_t) (len - 2), (uint8_t *) result);
-    result[len / 2 - 1] = '\0';
-    if (slen != NULL) *slen = len / 2 - 1;
+bool mg_span(struct mg_str s, struct mg_str *a, struct mg_str *b, char sep) {
+  if (s.len == 0 || s.buf == NULL) {
+    return false;  // Empty string, nothing to span - fail
+  } else {
+    size_t len = 0;
+    while (len < s.len && s.buf[len] != sep) len++;  // Find separator
+    if (a) *a = mg_str_n(s.buf, len);                // Init a
+    if (b) *b = mg_str_n(s.buf + len, s.len - len);  // Init b
+    if (b && len < s.len) b->buf++, b->len--;        // Skip separator
+    return true;
   }
-  return result;
 }
 
-long mg_json_get_long(struct mg_str json, const char *path, long dflt) {
-  double dv;
-  long result = dflt;
-  if (mg_json_get_num(json, path, &dv)) result = (long) dv;
-  return result;
+bool mg_str_to_num(struct mg_str str, int base, void *val, size_t val_len) {
+  size_t i = 0, ndigits = 0;
+  uint64_t max = val_len == sizeof(uint8_t)   ? 0xFF
+                 : val_len == sizeof(uint16_t) ? 0xFFFF
+                 : val_len == sizeof(uint32_t) ? 0xFFFFFFFF
+                                : (uint64_t) ~0;
+  uint64_t result = 0;
+  if (max == (uint64_t) ~0 && val_len != sizeof(uint64_t)) return false;
+  if (base == 0 && str.len >= 2) {
+    if (str.buf[i] == '0') {
+      i++;
+      base = str.buf[i] == 'b' ? 2 : str.buf[i] == 'x' ? 16 : 10;
+      if (base != 10) ++i;
+    } else {
+      base = 10;
+    }
+  }
+  switch (base) {
+    case 2:
+      while (i < str.len && (str.buf[i] == '0' || str.buf[i] == '1')) {
+        uint64_t digit = (uint64_t) (str.buf[i] - '0');
+        if (result > max/2) return false;  // Overflow
+        result *= 2;
+        if (result > max - digit) return false;  // Overflow
+        result += digit;
+        i++, ndigits++;
+      }
+      break;
+    case 10:
+      while (i < str.len && str.buf[i] >= '0' && str.buf[i] <= '9') {
+        uint64_t digit = (uint64_t) (str.buf[i] - '0');
+        if (result > max/10) return false;  // Overflow
+        result *= 10;
+        if (result > max - digit) return false;  // Overflow
+        result += digit;
+        i++, ndigits++;
+    }
+      break;
+    case 16:
+      while (i < str.len) {
+        char c = str.buf[i];
+        uint64_t digit = (c >= '0' && c <= '9')   ? (uint64_t) (c - '0')
+                         : (c >= 'A' && c <= 'F') ? (uint64_t) (c - '7')
+                         : (c >= 'a' && c <= 'f') ? (uint64_t) (c - 'W')
+                                                  : (uint64_t) ~0;
+        if (digit == (uint64_t) ~0) break;
+        if (result > max/16) return false;  // Overflow
+        result *= 16;
+        if (result > max - digit) return false;  // Overflow
+        result += digit;
+        i++, ndigits++;
+      }
+      break;
+    default:
+      return false;
+  }
+  if (ndigits == 0) return false;
+  if (i != str.len) return false;
+  if (val_len == 1) {
+    *((uint8_t *) val) = (uint8_t) result;
+  } else if (val_len == 2) {
+    *((uint16_t *) val) = (uint16_t) result;
+  } else if (val_len == 4) {
+    *((uint32_t *) val) = (uint32_t) result;
+  } else {
+    *((uint64_t *) val) = (uint64_t) result;
+  }
+  return true;
 }
 
 #ifdef MG_ENABLE_LINES
-#line 1 "src/log.c"
+#line 1 "src/timer.c"
 #endif
 
 
 
+#define MG_TIMER_CALLED 4
 
-
-static void default_logger(char c, void *param) {
-  putchar(c);
-  (void) c, (void) param;
-}
-
-static int s_level = MG_LL_INFO;
-static mg_pfn_t s_log_func = default_logger;
-static void *s_log_func_param = NULL;
-
-void mg_log_set_fn(mg_pfn_t fn, void *param) {
-  s_log_func = fn;
-  s_log_func_param = param;
-}
-
-static void logc(unsigned char c) {
-  s_log_func((char) c, s_log_func_param);
-}
-
-static void logs(const char *buf, size_t len) {
-  size_t i;
-  for (i = 0; i < len; i++) logc(((unsigned char *) buf)[i]);
-}
-
-void mg_log_set(int log_level) {
-  MG_DEBUG(("Setting log level to %d", log_level));
-  s_level = log_level;
-}
-
-bool mg_log_prefix(int level, const char *file, int line, const char *fname) {
-  if (level <= s_level) {
-    const char *p = strrchr(file, '/');
-    char buf[41];
-    size_t n;
-    if (p == NULL) p = strrchr(file, '\\');
-    n = mg_snprintf(buf, sizeof(buf), "%llx %d %s:%d:%s", mg_millis(), level,
-                    p == NULL ? file : p + 1, line, fname);
-    if (n > sizeof(buf) - 2) n = sizeof(buf) - 2;
-    while (n < sizeof(buf)) buf[n++] = ' ';
-    logs(buf, n - 1);
-    return true;
-  } else {
-    return false;
-  }
+void mg_timer_init(struct mg_timer **head, struct mg_timer *t, uint64_t ms,
+                   unsigned flags, void (*fn)(void *), void *arg) {
+  t->id = 0, t->period_ms = ms, t->expire = 0;
+  t->flags = flags, t->fn = fn, t->arg = arg, t->next = *head;
+  *head = t;
 }
 
-void mg_log(const char *fmt, ...) {
-  va_list ap;
-  va_start(ap, fmt);
-  mg_vxprintf(s_log_func, s_log_func_param, fmt, &ap);
-  va_end(ap);
-  logc((unsigned char) '\n');
+void mg_timer_free(struct mg_timer **head, struct mg_timer *t) {
+  while (*head && *head != t) head = &(*head)->next;
+  if (*head) *head = t->next;
 }
 
-static unsigned char nibble(unsigned c) {
-  return (unsigned char) (c < 10 ? c + '0' : c + 'W');
+// t: expiration time, prd: period, now: current time. Return true if expired
+bool mg_timer_expired(uint64_t *t, uint64_t prd, uint64_t now) {
+  if (now + prd < *t) *t = 0;                    // Time wrapped? Reset timer
+  if (*t == 0) *t = now + prd;                   // Firt poll? Set expiration
+  if (*t > now) return false;                    // Not expired yet, return
+  *t = (now - *t) > prd ? now + prd : *t + prd;  // Next expiration time
+  return true;                                   // Expired, return true
 }
 
-#define ISPRINT(x) ((x) >= ' ' && (x) <= '~')
-void mg_hexdump(const void *buf, size_t len) {
-  const unsigned char *p = (const unsigned char *) buf;
-  unsigned char ascii[16], alen = 0;
-  size_t i;
-  for (i = 0; i < len; i++) {
-    if ((i % 16) == 0) {
-      // Print buffered ascii chars
-      if (i > 0) logs("  ", 2), logs((char *) ascii, 16), logc('\n'), alen = 0;
-      // Print hex address, then \t
-      logc(nibble((i >> 12) & 15)), logc(nibble((i >> 8) & 15)),
-          logc(nibble((i >> 4) & 15)), logc('0'), logs("   ", 3);
-    }
-    logc(nibble(p[i] >> 4)), logc(nibble(p[i] & 15));  // Two nibbles, e.g. c5
-    logc(' ');                                         // Space after hex number
-    ascii[alen++] = ISPRINT(p[i]) ? p[i] : '.';        // Add to the ascii buf
+void mg_timer_poll(struct mg_timer **head, uint64_t now_ms) {
+  struct mg_timer *t, *tmp;
+  for (t = *head; t != NULL; t = tmp) {
+    bool once = t->expire == 0 && (t->flags & MG_TIMER_RUN_NOW) &&
+                !(t->flags & MG_TIMER_CALLED);  // Handle MG_TIMER_NOW only once
+    bool expired = mg_timer_expired(&t->expire, t->period_ms, now_ms);
+    tmp = t->next;
+    if (!once && !expired) continue;
+    if ((t->flags & MG_TIMER_REPEAT) || !(t->flags & MG_TIMER_CALLED)) {
+      t->fn(t->arg);
+    }
+    t->flags |= MG_TIMER_CALLED;
   }
-  while (alen < 16) logs("   ", 3), ascii[alen++] = ' ';
-  logs("  ", 2), logs((char *) ascii, 16), logc('\n');
 }
 
 #ifdef MG_ENABLE_LINES
-#line 1 "src/md5.c"
+#line 1 "src/tls_aes128.c"
 #endif
+/******************************************************************************
+ *
+ * THIS SOURCE CODE IS HEREBY PLACED INTO THE PUBLIC DOMAIN FOR THE GOOD OF ALL
+ *
+ * This is a simple and straightforward implementation of the AES Rijndael
+ * 128-bit block cipher designed by Vincent Rijmen and Joan Daemen. The focus
+ * of this work was correctness & accuracy.  It is written in 'C' without any
+ * particular focus upon optimization or speed. It should be endian (memory
+ * byte order) neutral since the few places that care are handled explicitly.
+ *
+ * This implementation of Rijndael was created by Steven M. Gibson of GRC.com.
+ *
+ * It is intended for general purpose use, but was written in support of GRC's
+ * reference implementation of the SQRL (Secure Quick Reliable Login) client.
+ *
+ * See:    http://csrc.nist.gov/archive/aes/rijndael/wsdindex.html
+ *
+ * NO COPYRIGHT IS CLAIMED IN THIS WORK, HOWEVER, NEITHER IS ANY WARRANTY MADE
+ * REGARDING ITS FITNESS FOR ANY PARTICULAR PURPOSE. USE IT AT YOUR OWN RISK.
+ *
+ *******************************************************************************/
+
+/******************************************************************************/
+#define AES_DECRYPTION 1  // whether AES decryption is supported
+/******************************************************************************/
+
+#define MG_ENCRYPT 1  // specify whether we're encrypting
+#define MG_DECRYPT 0  // or decrypting
+
+
+
+
+
+#if MG_TLS == MG_TLS_BUILTIN
+/******************************************************************************
+ *  AES_INIT_KEYGEN_TABLES : MUST be called once before any AES use
+ ******************************************************************************/
+static void aes_init_keygen_tables(void);
+
+/******************************************************************************
+ *  AES_SETKEY : called to expand the key for encryption or decryption
+ ******************************************************************************/
+static int aes_setkey(aes_context *ctx,  // pointer to context
+                      int mode,          // 1 or 0 for Encrypt/Decrypt
+                      const uchar *key,  // AES input key
+                      uint keysize);  // size in bytes (must be 16, 24, 32 for
+                                      // 128, 192 or 256-bit keys respectively)
+                                      // returns 0 for success
+
+/******************************************************************************
+ *  AES_CIPHER : called to encrypt or decrypt ONE 128-bit block of data
+ ******************************************************************************/
+static int aes_cipher(aes_context *ctx,       // pointer to context
+                      const uchar input[16],  // 128-bit block to en/decipher
+                      uchar output[16]);      // 128-bit output result block
+                                              // returns 0 for success
+
+/******************************************************************************
+ *  GCM_CONTEXT : GCM context / holds keytables, instance data, and AES ctx
+ ******************************************************************************/
+typedef struct {
+  int mode;             // cipher direction: encrypt/decrypt
+  uint64_t len;         // cipher data length processed so far
+  uint64_t add_len;     // total add data length
+  uint64_t HL[16];      // precalculated lo-half HTable
+  uint64_t HH[16];      // precalculated hi-half HTable
+  uchar base_ectr[16];  // first counter-mode cipher output for tag
+  uchar y[16];          // the current cipher-input IV|Counter value
+  uchar buf[16];        // buf working value
+  aes_context aes_ctx;  // cipher context used
+} gcm_context;
+
+/******************************************************************************
+ *  GCM_SETKEY : sets the GCM (and AES) keying material for use
+ ******************************************************************************/
+static int gcm_setkey(
+    gcm_context *ctx,   // caller-provided context ptr
+    const uchar *key,   // pointer to cipher key
+    const uint keysize  // size in bytes (must be 16, 24, 32 for
+                        // 128, 192 or 256-bit keys respectively)
+);                      // returns 0 for success
+
+/******************************************************************************
+ *
+ *  GCM_CRYPT_AND_TAG
+ *
+ *  This either encrypts or decrypts the user-provided data and, either
+ *  way, generates an authentication tag of the requested length. It must be
+ *  called with a GCM context whose key has already been set with GCM_SETKEY.
+ *
+ *  The user would typically call this explicitly to ENCRYPT a buffer of data
+ *  and optional associated data, and produce its an authentication tag.
+ *
+ *  To reverse the process the user would typically call the companion
+ *  GCM_AUTH_DECRYPT function to decrypt data and verify a user-provided
+ *  authentication tag.  The GCM_AUTH_DECRYPT function calls this function
+ *  to perform its decryption and tag generation, which it then compares.
+ *
+ ******************************************************************************/
+static int gcm_crypt_and_tag(
+    gcm_context *ctx,    // gcm context with key already setup
+    int mode,            // cipher direction: MG_ENCRYPT (1) or MG_DECRYPT (0)
+    const uchar *iv,     // pointer to the 12-byte initialization vector
+    size_t iv_len,       // byte length if the IV. should always be 12
+    const uchar *add,    // pointer to the non-ciphered additional data
+    size_t add_len,      // byte length of the additional AEAD data
+    const uchar *input,  // pointer to the cipher data source
+    uchar *output,       // pointer to the cipher data destination
+    size_t length,       // byte length of the cipher data
+    uchar *tag,          // pointer to the tag to be generated
+    size_t tag_len);     // byte length of the tag to be generated
+
+/******************************************************************************
+ *
+ *  GCM_START
+ *
+ *  Given a user-provided GCM context, this initializes it, sets the encryption
+ *  mode, and preprocesses the initialization vector and additional AEAD data.
+ *
+ ******************************************************************************/
+static int gcm_start(
+    gcm_context *ctx,  // pointer to user-provided GCM context
+    int mode,          // MG_ENCRYPT (1) or MG_DECRYPT (0)
+    const uchar *iv,   // pointer to initialization vector
+    size_t iv_len,     // IV length in bytes (should == 12)
+    const uchar *add,  // pointer to additional AEAD data (NULL if none)
+    size_t add_len);   // length of additional AEAD data (bytes)
+
+/******************************************************************************
+ *
+ *  GCM_UPDATE
+ *
+ *  This is called once or more to process bulk plaintext or ciphertext data.
+ *  We give this some number of bytes of input and it returns the same number
+ *  of output bytes. If called multiple times (which is fine) all but the final
+ *  invocation MUST be called with length mod 16 == 0. (Only the final call can
+ *  have a partial block length of < 128 bits.)
+ *
+ ******************************************************************************/
+static int gcm_update(gcm_context *ctx,  // pointer to user-provided GCM context
+                      size_t length,     // length, in bytes, of data to process
+                      const uchar *input,  // pointer to source data
+                      uchar *output);      // pointer to destination data
+
+/******************************************************************************
+ *
+ *  GCM_FINISH
+ *
+ *  This is called once after all calls to GCM_UPDATE to finalize the GCM.
+ *  It performs the final GHASH to produce the resulting authentication TAG.
+ *
+ ******************************************************************************/
+static int gcm_finish(
+    gcm_context *ctx,  // pointer to user-provided GCM context
+    uchar *tag,        // ptr to tag buffer - NULL if tag_len = 0
+    size_t tag_len);   // length, in bytes, of the tag-receiving buf
+
+/******************************************************************************
+ *
+ *  GCM_ZERO_CTX
+ *
+ *  The GCM context contains both the GCM context and the AES context.
+ *  This includes keying and key-related material which is security-
+ *  sensitive, so it MUST be zeroed after use. This function does that.
+ *
+ ******************************************************************************/
+static void gcm_zero_ctx(gcm_context *ctx);
+
+/******************************************************************************
+ *
+ * THIS SOURCE CODE IS HEREBY PLACED INTO THE PUBLIC DOMAIN FOR THE GOOD OF ALL
+ *
+ * This is a simple and straightforward implementation of the AES Rijndael
+ * 128-bit block cipher designed by Vincent Rijmen and Joan Daemen. The focus
+ * of this work was correctness & accuracy.  It is written in 'C' without any
+ * particular focus upon optimization or speed. It should be endian (memory
+ * byte order) neutral since the few places that care are handled explicitly.
+ *
+ * This implementation of Rijndael was created by Steven M. Gibson of GRC.com.
+ *
+ * It is intended for general purpose use, but was written in support of GRC's
+ * reference implementation of the SQRL (Secure Quick Reliable Login) client.
+ *
+ * See:    http://csrc.nist.gov/archive/aes/rijndael/wsdindex.html
+ *
+ * NO COPYRIGHT IS CLAIMED IN THIS WORK, HOWEVER, NEITHER IS ANY WARRANTY MADE
+ * REGARDING ITS FITNESS FOR ANY PARTICULAR PURPOSE. USE IT AT YOUR OWN RISK.
+ *
+ *******************************************************************************/
+
+
+
+
+static int aes_tables_inited = 0;  // run-once flag for performing key
+                                   // expasion table generation (see below)
+/*
+ *  The following static local tables must be filled-in before the first use of
+ *  the GCM or AES ciphers. They are used for the AES key expansion/scheduling
+ *  and once built are read-only and thread safe. The "gcm_initialize" function
+ *  must be called once during system initialization to populate these arrays
+ *  for subsequent use by the AES key scheduler. If they have not been built
+ *  before attempted use, an error will be returned to the caller.
+ *
+ *  NOTE: GCM Encryption/Decryption does NOT REQUIRE AES decryption. Since
+ *  GCM uses AES in counter-mode, where the AES cipher output is XORed with
+ *  the GCM input, we ONLY NEED AES encryption.  Thus, to save space AES
+ *  decryption is typically disabled by setting AES_DECRYPTION to 0 in aes.h.
+ */
+// We always need our forward tables
+static uchar FSb[256];     // Forward substitution box (FSb)
+static uint32_t FT0[256];  // Forward key schedule assembly tables
+static uint32_t FT1[256];
+static uint32_t FT2[256];
+static uint32_t FT3[256];
+
+#if AES_DECRYPTION         // We ONLY need reverse for decryption
+static uchar RSb[256];     // Reverse substitution box (RSb)
+static uint32_t RT0[256];  // Reverse key schedule assembly tables
+static uint32_t RT1[256];
+static uint32_t RT2[256];
+static uint32_t RT3[256];
+#endif /* AES_DECRYPTION */
+
+static uint32_t RCON[10];  // AES round constants
 
+/*
+ * Platform Endianness Neutralizing Load and Store Macro definitions
+ * AES wants platform-neutral Little Endian (LE) byte ordering
+ */
+#define GET_UINT32_LE(n, b, i)                                               \
+  {                                                                          \
+    (n) = ((uint32_t) (b)[(i)]) | ((uint32_t) (b)[(i) + 1] << 8) |           \
+          ((uint32_t) (b)[(i) + 2] << 16) | ((uint32_t) (b)[(i) + 3] << 24); \
+  }
 
-
-#if defined(MG_ENABLE_MD5) && MG_ENABLE_MD5
-
-static void mg_byte_reverse(unsigned char *buf, unsigned longs) {
-  if (MG_BIG_ENDIAN) {
-    do {
-      uint32_t t = (uint32_t) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
-                   ((unsigned) buf[1] << 8 | buf[0]);
-      *(uint32_t *) buf = t;
-      buf += 4;
-    } while (--longs);
-  } else {
-    (void) buf, (void) longs;  // Little endian. Do nothing
+#define PUT_UINT32_LE(n, b, i)          \
+  {                                     \
+    (b)[(i)] = (uchar) ((n));           \
+    (b)[(i) + 1] = (uchar) ((n) >> 8);  \
+    (b)[(i) + 2] = (uchar) ((n) >> 16); \
+    (b)[(i) + 3] = (uchar) ((n) >> 24); \
   }
-}
 
-#define F1(x, y, z) (z ^ (x & (y ^ z)))
-#define F2(x, y, z) F1(z, x, y)
-#define F3(x, y, z) (x ^ y ^ z)
-#define F4(x, y, z) (y ^ (x | ~z))
+/*
+ *  AES forward and reverse encryption round processing macros
+ */
+#define AES_FROUND(X0, X1, X2, X3, Y0, Y1, Y2, Y3)          \
+  {                                                         \
+    X0 = *RK++ ^ FT0[(Y0) & 0xFF] ^ FT1[(Y1 >> 8) & 0xFF] ^ \
+         FT2[(Y2 >> 16) & 0xFF] ^ FT3[(Y3 >> 24) & 0xFF];   \
+                                                            \
+    X1 = *RK++ ^ FT0[(Y1) & 0xFF] ^ FT1[(Y2 >> 8) & 0xFF] ^ \
+         FT2[(Y3 >> 16) & 0xFF] ^ FT3[(Y0 >> 24) & 0xFF];   \
+                                                            \
+    X2 = *RK++ ^ FT0[(Y2) & 0xFF] ^ FT1[(Y3 >> 8) & 0xFF] ^ \
+         FT2[(Y0 >> 16) & 0xFF] ^ FT3[(Y1 >> 24) & 0xFF];   \
+                                                            \
+    X3 = *RK++ ^ FT0[(Y3) & 0xFF] ^ FT1[(Y0 >> 8) & 0xFF] ^ \
+         FT2[(Y1 >> 16) & 0xFF] ^ FT3[(Y2 >> 24) & 0xFF];   \
+  }
 
-#define MD5STEP(f, w, x, y, z, data, s) \
-  (w += f(x, y, z) + data, w = w << s | w >> (32 - s), w += x)
+#define AES_RROUND(X0, X1, X2, X3, Y0, Y1, Y2, Y3)          \
+  {                                                         \
+    X0 = *RK++ ^ RT0[(Y0) & 0xFF] ^ RT1[(Y3 >> 8) & 0xFF] ^ \
+         RT2[(Y2 >> 16) & 0xFF] ^ RT3[(Y1 >> 24) & 0xFF];   \
+                                                            \
+    X1 = *RK++ ^ RT0[(Y1) & 0xFF] ^ RT1[(Y0 >> 8) & 0xFF] ^ \
+         RT2[(Y3 >> 16) & 0xFF] ^ RT3[(Y2 >> 24) & 0xFF];   \
+                                                            \
+    X2 = *RK++ ^ RT0[(Y2) & 0xFF] ^ RT1[(Y1 >> 8) & 0xFF] ^ \
+         RT2[(Y0 >> 16) & 0xFF] ^ RT3[(Y3 >> 24) & 0xFF];   \
+                                                            \
+    X3 = *RK++ ^ RT0[(Y3) & 0xFF] ^ RT1[(Y2 >> 8) & 0xFF] ^ \
+         RT2[(Y1 >> 16) & 0xFF] ^ RT3[(Y0 >> 24) & 0xFF];   \
+  }
 
 /*
- * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
- * initialization constants.
+ *  These macros improve the readability of the key
+ *  generation initialization code by collapsing
+ *  repetitive common operations into logical pieces.
  */
-void mg_md5_init(mg_md5_ctx *ctx) {
-  ctx->buf[0] = 0x67452301;
-  ctx->buf[1] = 0xefcdab89;
-  ctx->buf[2] = 0x98badcfe;
-  ctx->buf[3] = 0x10325476;
+#define ROTL8(x) ((x << 8) & 0xFFFFFFFF) | (x >> 24)
+#define XTIME(x) ((x << 1) ^ ((x & 0x80) ? 0x1B : 0x00))
+#define MUL(x, y) ((x && y) ? pow[(log[x] + log[y]) % 255] : 0)
+#define MIX(x, y)                     \
+  {                                   \
+    y = ((y << 1) | (y >> 7)) & 0xFF; \
+    x ^= y;                           \
+  }
+#define CPY128     \
+  {                \
+    *RK++ = *SK++; \
+    *RK++ = *SK++; \
+    *RK++ = *SK++; \
+    *RK++ = *SK++; \
+  }
 
-  ctx->bits[0] = 0;
-  ctx->bits[1] = 0;
-}
+/******************************************************************************
+ *
+ *  AES_INIT_KEYGEN_TABLES
+ *
+ *  Fills the AES key expansion tables allocated above with their static
+ *  data. This is not "per key" data, but static system-wide read-only
+ *  table data. THIS FUNCTION IS NOT THREAD SAFE. It must be called once
+ *  at system initialization to setup the tables for all subsequent use.
+ *
+ ******************************************************************************/
+void aes_init_keygen_tables(void) {
+  int i, x, y, z;  // general purpose iteration and computation locals
+  int pow[256];
+  int log[256];
+
+  if (aes_tables_inited) return;
+
+  // fill the 'pow' and 'log' tables over GF(2^8)
+  for (i = 0, x = 1; i < 256; i++) {
+    pow[i] = x;
+    log[x] = i;
+    x = (x ^ XTIME(x)) & 0xFF;
+  }
+  // compute the round constants
+  for (i = 0, x = 1; i < 10; i++) {
+    RCON[i] = (uint32_t) x;
+    x = XTIME(x) & 0xFF;
+  }
+  // fill the forward and reverse substitution boxes
+  FSb[0x00] = 0x63;
+#if AES_DECRYPTION  // whether AES decryption is supported
+  RSb[0x63] = 0x00;
+#endif /* AES_DECRYPTION */
+
+  for (i = 1; i < 256; i++) {
+    x = y = pow[255 - log[i]];
+    MIX(x, y);
+    MIX(x, y);
+    MIX(x, y);
+    MIX(x, y);
+    FSb[i] = (uchar) (x ^= 0x63);
+#if AES_DECRYPTION  // whether AES decryption is supported
+    RSb[x] = (uchar) i;
+#endif /* AES_DECRYPTION */
+  }
+  // generate the forward and reverse key expansion tables
+  for (i = 0; i < 256; i++) {
+    x = FSb[i];
+    y = XTIME(x) & 0xFF;
+    z = (y ^ x) & 0xFF;
 
-static void mg_md5_transform(uint32_t buf[4], uint32_t const in[16]) {
-  uint32_t a, b, c, d;
+    FT0[i] = ((uint32_t) y) ^ ((uint32_t) x << 8) ^ ((uint32_t) x << 16) ^
+             ((uint32_t) z << 24);
 
-  a = buf[0];
-  b = buf[1];
-  c = buf[2];
-  d = buf[3];
+    FT1[i] = ROTL8(FT0[i]);
+    FT2[i] = ROTL8(FT1[i]);
+    FT3[i] = ROTL8(FT2[i]);
 
-  MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
-  MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
-  MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
-  MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
-  MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
-  MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
-  MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
-  MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
-  MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
-  MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
-  MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
-  MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
-  MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
-  MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
-  MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
-  MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
+#if AES_DECRYPTION  // whether AES decryption is supported
+    x = RSb[i];
 
-  MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
-  MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
-  MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
-  MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
-  MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
-  MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
-  MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
-  MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
-  MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
-  MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
-  MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
-  MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
-  MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
-  MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
-  MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
-  MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
+    RT0[i] = ((uint32_t) MUL(0x0E, x)) ^ ((uint32_t) MUL(0x09, x) << 8) ^
+             ((uint32_t) MUL(0x0D, x) << 16) ^ ((uint32_t) MUL(0x0B, x) << 24);
 
-  MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
-  MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
-  MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
-  MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
-  MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
-  MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
-  MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
-  MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
-  MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
-  MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
-  MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
-  MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
-  MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
-  MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
-  MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
-  MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
+    RT1[i] = ROTL8(RT0[i]);
+    RT2[i] = ROTL8(RT1[i]);
+    RT3[i] = ROTL8(RT2[i]);
+#endif /* AES_DECRYPTION */
+  }
+  aes_tables_inited = 1;  // flag that the tables have been generated
+}  // to permit subsequent use of the AES cipher
+
+/******************************************************************************
+ *
+ *  AES_SET_ENCRYPTION_KEY
+ *
+ *  This is called by 'aes_setkey' when we're establishing a key for
+ *  subsequent encryption.  We give it a pointer to the encryption
+ *  context, a pointer to the key, and the key's length in bytes.
+ *  Valid lengths are: 16, 24 or 32 bytes (128, 192, 256 bits).
+ *
+ ******************************************************************************/
+static int aes_set_encryption_key(aes_context *ctx, const uchar *key,
+                                  uint keysize) {
+  uint i;                  // general purpose iteration local
+  uint32_t *RK = ctx->rk;  // initialize our RoundKey buffer pointer
+
+  for (i = 0; i < (keysize >> 2); i++) {
+    GET_UINT32_LE(RK[i], key, i << 2);
+  }
 
-  MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
-  MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
-  MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
-  MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
-  MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
-  MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
-  MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
-  MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
-  MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
-  MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
-  MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
-  MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
-  MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
-  MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
-  MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
-  MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
+  switch (ctx->rounds) {
+    case 10:
+      for (i = 0; i < 10; i++, RK += 4) {
+        RK[4] = RK[0] ^ RCON[i] ^ ((uint32_t) FSb[(RK[3] >> 8) & 0xFF]) ^
+                ((uint32_t) FSb[(RK[3] >> 16) & 0xFF] << 8) ^
+                ((uint32_t) FSb[(RK[3] >> 24) & 0xFF] << 16) ^
+                ((uint32_t) FSb[(RK[3]) & 0xFF] << 24);
+
+        RK[5] = RK[1] ^ RK[4];
+        RK[6] = RK[2] ^ RK[5];
+        RK[7] = RK[3] ^ RK[6];
+      }
+      break;
 
-  buf[0] += a;
-  buf[1] += b;
-  buf[2] += c;
-  buf[3] += d;
-}
+    case 12:
+      for (i = 0; i < 8; i++, RK += 6) {
+        RK[6] = RK[0] ^ RCON[i] ^ ((uint32_t) FSb[(RK[5] >> 8) & 0xFF]) ^
+                ((uint32_t) FSb[(RK[5] >> 16) & 0xFF] << 8) ^
+                ((uint32_t) FSb[(RK[5] >> 24) & 0xFF] << 16) ^
+                ((uint32_t) FSb[(RK[5]) & 0xFF] << 24);
+
+        RK[7] = RK[1] ^ RK[6];
+        RK[8] = RK[2] ^ RK[7];
+        RK[9] = RK[3] ^ RK[8];
+        RK[10] = RK[4] ^ RK[9];
+        RK[11] = RK[5] ^ RK[10];
+      }
+      break;
 
-void mg_md5_update(mg_md5_ctx *ctx, const unsigned char *buf, size_t len) {
-  uint32_t t;
+    case 14:
+      for (i = 0; i < 7; i++, RK += 8) {
+        RK[8] = RK[0] ^ RCON[i] ^ ((uint32_t) FSb[(RK[7] >> 8) & 0xFF]) ^
+                ((uint32_t) FSb[(RK[7] >> 16) & 0xFF] << 8) ^
+                ((uint32_t) FSb[(RK[7] >> 24) & 0xFF] << 16) ^
+                ((uint32_t) FSb[(RK[7]) & 0xFF] << 24);
+
+        RK[9] = RK[1] ^ RK[8];
+        RK[10] = RK[2] ^ RK[9];
+        RK[11] = RK[3] ^ RK[10];
+
+        RK[12] = RK[4] ^ ((uint32_t) FSb[(RK[11]) & 0xFF]) ^
+                 ((uint32_t) FSb[(RK[11] >> 8) & 0xFF] << 8) ^
+                 ((uint32_t) FSb[(RK[11] >> 16) & 0xFF] << 16) ^
+                 ((uint32_t) FSb[(RK[11] >> 24) & 0xFF] << 24);
+
+        RK[13] = RK[5] ^ RK[12];
+        RK[14] = RK[6] ^ RK[13];
+        RK[15] = RK[7] ^ RK[14];
+      }
+      break;
 
-  t = ctx->bits[0];
-  if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t) ctx->bits[1]++;
-  ctx->bits[1] += (uint32_t) len >> 29;
+    default:
+      return -1;
+  }
+  return (0);
+}
+
+#if AES_DECRYPTION  // whether AES decryption is supported
+
+/******************************************************************************
+ *
+ *  AES_SET_DECRYPTION_KEY
+ *
+ *  This is called by 'aes_setkey' when we're establishing a
+ *  key for subsequent decryption.  We give it a pointer to
+ *  the encryption context, a pointer to the key, and the key's
+ *  length in bits. Valid lengths are: 128, 192, or 256 bits.
+ *
+ ******************************************************************************/
+static int aes_set_decryption_key(aes_context *ctx, const uchar *key,
+                                  uint keysize) {
+  int i, j;
+  aes_context cty;         // a calling aes context for set_encryption_key
+  uint32_t *RK = ctx->rk;  // initialize our RoundKey buffer pointer
+  uint32_t *SK;
+  int ret;
 
-  t = (t >> 3) & 0x3f;
+  cty.rounds = ctx->rounds;  // initialize our local aes context
+  cty.rk = cty.buf;          // round count and key buf pointer
 
-  if (t) {
-    unsigned char *p = (unsigned char *) ctx->in + t;
+  if ((ret = aes_set_encryption_key(&cty, key, keysize)) != 0) return (ret);
 
-    t = 64 - t;
-    if (len < t) {
-      memcpy(p, buf, len);
-      return;
+  SK = cty.rk + cty.rounds * 4;
+
+  CPY128  // copy a 128-bit block from *SK to *RK
+
+      for (i = ctx->rounds - 1, SK -= 8; i > 0; i--, SK -= 8) {
+    for (j = 0; j < 4; j++, SK++) {
+      *RK++ = RT0[FSb[(*SK) & 0xFF]] ^ RT1[FSb[(*SK >> 8) & 0xFF]] ^
+              RT2[FSb[(*SK >> 16) & 0xFF]] ^ RT3[FSb[(*SK >> 24) & 0xFF]];
     }
-    memcpy(p, buf, t);
-    mg_byte_reverse(ctx->in, 16);
-    mg_md5_transform(ctx->buf, (uint32_t *) ctx->in);
-    buf += t;
-    len -= t;
+  }
+  CPY128  // copy a 128-bit block from *SK to *RK
+      memset(&cty, 0, sizeof(aes_context));  // clear local aes context
+  return (0);
+}
+
+#endif /* AES_DECRYPTION */
+
+/******************************************************************************
+ *
+ *  AES_SETKEY
+ *
+ *  Invoked to establish the key schedule for subsequent encryption/decryption
+ *
+ ******************************************************************************/
+static int aes_setkey(aes_context *ctx,  // AES context provided by our caller
+                      int mode,          // ENCRYPT or DECRYPT flag
+                      const uchar *key,  // pointer to the key
+                      uint keysize)      // key length in bytes
+{
+  // since table initialization is not thread safe, we could either add
+  // system-specific mutexes and init the AES key generation tables on
+  // demand, or ask the developer to simply call "gcm_initialize" once during
+  // application startup before threading begins. That's what we choose.
+  if (!aes_tables_inited) return (-1);  // fail the call when not inited.
+
+  ctx->mode = mode;    // capture the key type we're creating
+  ctx->rk = ctx->buf;  // initialize our round key pointer
+
+  switch (keysize)  // set the rounds count based upon the keysize
+  {
+    case 16:
+      ctx->rounds = 10;
+      break;  // 16-byte, 128-bit key
+    case 24:
+      ctx->rounds = 12;
+      break;  // 24-byte, 192-bit key
+    case 32:
+      ctx->rounds = 14;
+      break;  // 32-byte, 256-bit key
+    default:
+      return (-1);
   }
 
-  while (len >= 64) {
-    memcpy(ctx->in, buf, 64);
-    mg_byte_reverse(ctx->in, 16);
-    mg_md5_transform(ctx->buf, (uint32_t *) ctx->in);
-    buf += 64;
-    len -= 64;
+#if AES_DECRYPTION
+  if (mode == MG_DECRYPT)  // expand our key for encryption or decryption
+    return (aes_set_decryption_key(ctx, key, keysize));
+  else /* MG_ENCRYPT */
+#endif /* AES_DECRYPTION */
+    return (aes_set_encryption_key(ctx, key, keysize));
+}
+
+/******************************************************************************
+ *
+ *  AES_CIPHER
+ *
+ *  Perform AES encryption and decryption.
+ *  The AES context will have been setup with the encryption mode
+ *  and all keying information appropriate for the task.
+ *
+ ******************************************************************************/
+static int aes_cipher(aes_context *ctx, const uchar input[16],
+                      uchar output[16]) {
+  int i;
+  uint32_t *RK, X0, X1, X2, X3, Y0, Y1, Y2, Y3;  // general purpose locals
+
+  RK = ctx->rk;
+
+  GET_UINT32_LE(X0, input, 0);
+  X0 ^= *RK++;  // load our 128-bit
+  GET_UINT32_LE(X1, input, 4);
+  X1 ^= *RK++;  // input buffer in a storage
+  GET_UINT32_LE(X2, input, 8);
+  X2 ^= *RK++;  // memory endian-neutral way
+  GET_UINT32_LE(X3, input, 12);
+  X3 ^= *RK++;
+
+#if AES_DECRYPTION  // whether AES decryption is supported
+
+  if (ctx->mode == MG_DECRYPT) {
+    for (i = (ctx->rounds >> 1) - 1; i > 0; i--) {
+      AES_RROUND(Y0, Y1, Y2, Y3, X0, X1, X2, X3);
+      AES_RROUND(X0, X1, X2, X3, Y0, Y1, Y2, Y3);
+    }
+
+    AES_RROUND(Y0, Y1, Y2, Y3, X0, X1, X2, X3);
+
+    X0 = *RK++ ^ ((uint32_t) RSb[(Y0) & 0xFF]) ^
+         ((uint32_t) RSb[(Y3 >> 8) & 0xFF] << 8) ^
+         ((uint32_t) RSb[(Y2 >> 16) & 0xFF] << 16) ^
+         ((uint32_t) RSb[(Y1 >> 24) & 0xFF] << 24);
+
+    X1 = *RK++ ^ ((uint32_t) RSb[(Y1) & 0xFF]) ^
+         ((uint32_t) RSb[(Y0 >> 8) & 0xFF] << 8) ^
+         ((uint32_t) RSb[(Y3 >> 16) & 0xFF] << 16) ^
+         ((uint32_t) RSb[(Y2 >> 24) & 0xFF] << 24);
+
+    X2 = *RK++ ^ ((uint32_t) RSb[(Y2) & 0xFF]) ^
+         ((uint32_t) RSb[(Y1 >> 8) & 0xFF] << 8) ^
+         ((uint32_t) RSb[(Y0 >> 16) & 0xFF] << 16) ^
+         ((uint32_t) RSb[(Y3 >> 24) & 0xFF] << 24);
+
+    X3 = *RK++ ^ ((uint32_t) RSb[(Y3) & 0xFF]) ^
+         ((uint32_t) RSb[(Y2 >> 8) & 0xFF] << 8) ^
+         ((uint32_t) RSb[(Y1 >> 16) & 0xFF] << 16) ^
+         ((uint32_t) RSb[(Y0 >> 24) & 0xFF] << 24);
+  } else /* MG_ENCRYPT */
+  {
+#endif /* AES_DECRYPTION */
+
+    for (i = (ctx->rounds >> 1) - 1; i > 0; i--) {
+      AES_FROUND(Y0, Y1, Y2, Y3, X0, X1, X2, X3);
+      AES_FROUND(X0, X1, X2, X3, Y0, Y1, Y2, Y3);
+    }
+
+    AES_FROUND(Y0, Y1, Y2, Y3, X0, X1, X2, X3);
+
+    X0 = *RK++ ^ ((uint32_t) FSb[(Y0) & 0xFF]) ^
+         ((uint32_t) FSb[(Y1 >> 8) & 0xFF] << 8) ^
+         ((uint32_t) FSb[(Y2 >> 16) & 0xFF] << 16) ^
+         ((uint32_t) FSb[(Y3 >> 24) & 0xFF] << 24);
+
+    X1 = *RK++ ^ ((uint32_t) FSb[(Y1) & 0xFF]) ^
+         ((uint32_t) FSb[(Y2 >> 8) & 0xFF] << 8) ^
+         ((uint32_t) FSb[(Y3 >> 16) & 0xFF] << 16) ^
+         ((uint32_t) FSb[(Y0 >> 24) & 0xFF] << 24);
+
+    X2 = *RK++ ^ ((uint32_t) FSb[(Y2) & 0xFF]) ^
+         ((uint32_t) FSb[(Y3 >> 8) & 0xFF] << 8) ^
+         ((uint32_t) FSb[(Y0 >> 16) & 0xFF] << 16) ^
+         ((uint32_t) FSb[(Y1 >> 24) & 0xFF] << 24);
+
+    X3 = *RK++ ^ ((uint32_t) FSb[(Y3) & 0xFF]) ^
+         ((uint32_t) FSb[(Y0 >> 8) & 0xFF] << 8) ^
+         ((uint32_t) FSb[(Y1 >> 16) & 0xFF] << 16) ^
+         ((uint32_t) FSb[(Y2 >> 24) & 0xFF] << 24);
+
+#if AES_DECRYPTION  // whether AES decryption is supported
   }
+#endif /* AES_DECRYPTION */
+
+  PUT_UINT32_LE(X0, output, 0);
+  PUT_UINT32_LE(X1, output, 4);
+  PUT_UINT32_LE(X2, output, 8);
+  PUT_UINT32_LE(X3, output, 12);
+
+  return (0);
+}
+/* end of aes.c */
+/******************************************************************************
+ *
+ * THIS SOURCE CODE IS HEREBY PLACED INTO THE PUBLIC DOMAIN FOR THE GOOD OF ALL
+ *
+ * This is a simple and straightforward implementation of AES-GCM authenticated
+ * encryption. The focus of this work was correctness & accuracy. It is written
+ * in straight 'C' without any particular focus upon optimization or speed. It
+ * should be endian (memory byte order) neutral since the few places that care
+ * are handled explicitly.
+ *
+ * This implementation of AES-GCM was created by Steven M. Gibson of GRC.com.
+ *
+ * It is intended for general purpose use, but was written in support of GRC's
+ * reference implementation of the SQRL (Secure Quick Reliable Login) client.
+ *
+ * See:    http://csrc.nist.gov/publications/nistpubs/800-38D/SP-800-38D.pdf
+ *         http://csrc.nist.gov/groups/ST/toolkit/BCM/documents/proposedmodes/
+ *         gcm/gcm-revised-spec.pdf
+ *
+ * NO COPYRIGHT IS CLAIMED IN THIS WORK, HOWEVER, NEITHER IS ANY WARRANTY MADE
+ * REGARDING ITS FITNESS FOR ANY PARTICULAR PURPOSE. USE IT AT YOUR OWN RISK.
+ *
+ *******************************************************************************/
+
+/******************************************************************************
+ *                      ==== IMPLEMENTATION WARNING ====
+ *
+ *  This code was developed for use within SQRL's fixed environmnent. Thus, it
+ *  is somewhat less "general purpose" than it would be if it were designed as
+ *  a general purpose AES-GCM library. Specifically, it bothers with almost NO
+ *  error checking on parameter limits, buffer bounds, etc. It assumes that it
+ *  is being invoked by its author or by someone who understands the values it
+ *  expects to receive. Its behavior will be undefined otherwise.
+ *
+ *  All functions that might fail are defined to return 'ints' to indicate a
+ *  problem. Most do not do so now. But this allows for error propagation out
+ *  of internal functions if robust error checking should ever be desired.
+ *
+ ******************************************************************************/
+
+/* Calculating the "GHASH"
+ *
+ * There are many ways of calculating the so-called GHASH in software, each with
+ * a traditional size vs performance tradeoff.  The GHASH (Galois field hash) is
+ * an intriguing construction which takes two 128-bit strings (also the cipher's
+ * block size and the fundamental operation size for the system) and hashes them
+ * into a third 128-bit result.
+ *
+ * Many implementation solutions have been worked out that use large precomputed
+ * table lookups in place of more time consuming bit fiddling, and this approach
+ * can be scaled easily upward or downward as needed to change the time/space
+ * tradeoff. It's been studied extensively and there's a solid body of theory
+ * and practice.  For example, without using any lookup tables an implementation
+ * might obtain 119 cycles per byte throughput, whereas using a simple, though
+ * large, key-specific 64 kbyte 8-bit lookup table the performance jumps to 13
+ * cycles per byte.
+ *
+ * And Intel's processors have, since 2010, included an instruction which does
+ * the entire 128x128->128 bit job in just several 64x64->128 bit pieces.
+ *
+ * Since SQRL is interactive, and only processing a few 128-bit blocks, I've
+ * settled upon a relatively slower but appealing small-table compromise which
+ * folds a bunch of not only time consuming but also bit twiddling into a simple
+ * 16-entry table which is attributed to Victor Shoup's 1996 work while at
+ * Bellcore: "On Fast and Provably Secure MessageAuthentication Based on
+ * Universal Hashing."  See: http://www.shoup.net/papers/macs.pdf
+ * See, also section 4.1 of the "gcm-revised-spec" cited above.
+ */
 
-  memcpy(ctx->in, buf, len);
-}
+/*
+ *  This 16-entry table of pre-computed constants is used by the
+ *  GHASH multiplier to improve over a strictly table-free but
+ *  significantly slower 128x128 bit multiple within GF(2^128).
+ */
+static const uint64_t last4[16] = {
+    0x0000, 0x1c20, 0x3840, 0x2460, 0x7080, 0x6ca0, 0x48c0, 0x54e0,
+    0xe100, 0xfd20, 0xd940, 0xc560, 0x9180, 0x8da0, 0xa9c0, 0xb5e0};
 
-void mg_md5_final(mg_md5_ctx *ctx, unsigned char digest[16]) {
-  unsigned count;
-  unsigned char *p;
-  uint32_t *a;
+/*
+ * Platform Endianness Neutralizing Load and Store Macro definitions
+ * GCM wants platform-neutral Big Endian (BE) byte ordering
+ */
+#define GET_UINT32_BE(n, b, i)                                            \
+  {                                                                       \
+    (n) = ((uint32_t) (b)[(i)] << 24) | ((uint32_t) (b)[(i) + 1] << 16) | \
+          ((uint32_t) (b)[(i) + 2] << 8) | ((uint32_t) (b)[(i) + 3]);     \
+  }
 
-  count = (ctx->bits[0] >> 3) & 0x3F;
+#define PUT_UINT32_BE(n, b, i)          \
+  {                                     \
+    (b)[(i)] = (uchar) ((n) >> 24);     \
+    (b)[(i) + 1] = (uchar) ((n) >> 16); \
+    (b)[(i) + 2] = (uchar) ((n) >> 8);  \
+    (b)[(i) + 3] = (uchar) ((n));       \
+  }
 
-  p = ctx->in + count;
-  *p++ = 0x80;
-  count = 64 - 1 - count;
-  if (count < 8) {
-    memset(p, 0, count);
-    mg_byte_reverse(ctx->in, 16);
-    mg_md5_transform(ctx->buf, (uint32_t *) ctx->in);
-    memset(ctx->in, 0, 56);
-  } else {
-    memset(p, 0, count - 8);
+/******************************************************************************
+ *
+ *  GCM_INITIALIZE
+ *
+ *  Must be called once to initialize the GCM library.
+ *
+ *  At present, this only calls the AES keygen table generator, which expands
+ *  the AES keying tables for use. This is NOT A THREAD-SAFE function, so it
+ *  MUST be called during system initialization before a multi-threading
+ *  environment is running.
+ *
+ ******************************************************************************/
+int mg_gcm_initialize(void) {
+  aes_init_keygen_tables();
+  return (0);
+}
+
+/******************************************************************************
+ *
+ *  GCM_MULT
+ *
+ *  Performs a GHASH operation on the 128-bit input vector 'x', setting
+ *  the 128-bit output vector to 'x' times H using our precomputed tables.
+ *  'x' and 'output' are seen as elements of GCM's GF(2^128) Galois field.
+ *
+ ******************************************************************************/
+static void gcm_mult(gcm_context *ctx,   // pointer to established context
+                     const uchar x[16],  // pointer to 128-bit input vector
+                     uchar output[16])   // pointer to 128-bit output vector
+{
+  int i;
+  uchar lo, hi, rem;
+  uint64_t zh, zl;
+
+  lo = (uchar) (x[15] & 0x0f);
+  hi = (uchar) (x[15] >> 4);
+  zh = ctx->HH[lo];
+  zl = ctx->HL[lo];
+
+  for (i = 15; i >= 0; i--) {
+    lo = (uchar) (x[i] & 0x0f);
+    hi = (uchar) (x[i] >> 4);
+
+    if (i != 15) {
+      rem = (uchar) (zl & 0x0f);
+      zl = (zh << 60) | (zl >> 4);
+      zh = (zh >> 4);
+      zh ^= (uint64_t) last4[rem] << 48;
+      zh ^= ctx->HH[lo];
+      zl ^= ctx->HL[lo];
+    }
+    rem = (uchar) (zl & 0x0f);
+    zl = (zh << 60) | (zl >> 4);
+    zh = (zh >> 4);
+    zh ^= (uint64_t) last4[rem] << 48;
+    zh ^= ctx->HH[hi];
+    zl ^= ctx->HL[hi];
   }
-  mg_byte_reverse(ctx->in, 14);
+  PUT_UINT32_BE(zh >> 32, output, 0);
+  PUT_UINT32_BE(zh, output, 4);
+  PUT_UINT32_BE(zl >> 32, output, 8);
+  PUT_UINT32_BE(zl, output, 12);
+}
+
+/******************************************************************************
+ *
+ *  GCM_SETKEY
+ *
+ *  This is called to set the AES-GCM key. It initializes the AES key
+ *  and populates the gcm context's pre-calculated HTables.
+ *
+ ******************************************************************************/
+static int gcm_setkey(
+    gcm_context *ctx,    // pointer to caller-provided gcm context
+    const uchar *key,    // pointer to the AES encryption key
+    const uint keysize)  // size in bytes (must be 16, 24, 32 for
+                         // 128, 192 or 256-bit keys respectively)
+{
+  int ret, i, j;
+  uint64_t hi, lo;
+  uint64_t vl, vh;
+  unsigned char h[16];
+
+  memset(ctx, 0, sizeof(gcm_context));  // zero caller-provided GCM context
+  memset(h, 0, 16);                     // initialize the block to encrypt
+
+  // encrypt the null 128-bit block to generate a key-based value
+  // which is then used to initialize our GHASH lookup tables
+  if ((ret = aes_setkey(&ctx->aes_ctx, MG_ENCRYPT, key, keysize)) != 0)
+    return (ret);
+  if ((ret = aes_cipher(&ctx->aes_ctx, h, h)) != 0) return (ret);
+
+  GET_UINT32_BE(hi, h, 0);  // pack h as two 64-bit ints, big-endian
+  GET_UINT32_BE(lo, h, 4);
+  vh = (uint64_t) hi << 32 | lo;
+
+  GET_UINT32_BE(hi, h, 8);
+  GET_UINT32_BE(lo, h, 12);
+  vl = (uint64_t) hi << 32 | lo;
+
+  ctx->HL[8] = vl;  // 8 = 1000 corresponds to 1 in GF(2^128)
+  ctx->HH[8] = vh;
+  ctx->HH[0] = 0;  // 0 corresponds to 0 in GF(2^128)
+  ctx->HL[0] = 0;
+
+  for (i = 4; i > 0; i >>= 1) {
+    uint32_t T = (uint32_t) (vl & 1) * 0xe1000000U;
+    vl = (vh << 63) | (vl >> 1);
+    vh = (vh >> 1) ^ ((uint64_t) T << 32);
+    ctx->HL[i] = vl;
+    ctx->HH[i] = vh;
+  }
+  for (i = 2; i < 16; i <<= 1) {
+    uint64_t *HiL = ctx->HL + i, *HiH = ctx->HH + i;
+    vh = *HiH;
+    vl = *HiL;
+    for (j = 1; j < i; j++) {
+      HiH[j] = vh ^ ctx->HH[j];
+      HiL[j] = vl ^ ctx->HL[j];
+    }
+  }
+  return (0);
+}
+
+/******************************************************************************
+ *
+ *    GCM processing occurs four phases: SETKEY, START, UPDATE and FINISH.
+ *
+ *  SETKEY:
+ *
+ *   START: Sets the Encryption/Decryption mode.
+ *          Accepts the initialization vector and additional data.
+ *
+ *  UPDATE: Encrypts or decrypts the plaintext or ciphertext.
+ *
+ *  FINISH: Performs a final GHASH to generate the authentication tag.
+ *
+ ******************************************************************************
+ *
+ *  GCM_START
+ *
+ *  Given a user-provided GCM context, this initializes it, sets the encryption
+ *  mode, and preprocesses the initialization vector and additional AEAD data.
+ *
+ ******************************************************************************/
+int gcm_start(gcm_context *ctx,  // pointer to user-provided GCM context
+              int mode,          // GCM_ENCRYPT or GCM_DECRYPT
+              const uchar *iv,   // pointer to initialization vector
+              size_t iv_len,     // IV length in bytes (should == 12)
+              const uchar *add,  // ptr to additional AEAD data (NULL if none)
+              size_t add_len)    // length of additional AEAD data (bytes)
+{
+  int ret;             // our error return if the AES encrypt fails
+  uchar work_buf[16];  // XOR source built from provided IV if len != 16
+  const uchar *p;      // general purpose array pointer
+  size_t use_len;      // byte count to process, up to 16 bytes
+  size_t i;            // local loop iterator
+
+  // since the context might be reused under the same key
+  // we zero the working buffers for this next new process
+  memset(ctx->y, 0x00, sizeof(ctx->y));
+  memset(ctx->buf, 0x00, sizeof(ctx->buf));
+  ctx->len = 0;
+  ctx->add_len = 0;
+
+  ctx->mode = mode;                // set the GCM encryption/decryption mode
+  ctx->aes_ctx.mode = MG_ENCRYPT;  // GCM *always* runs AES in ENCRYPTION mode
+
+  if (iv_len == 12) {            // GCM natively uses a 12-byte, 96-bit IV
+    memcpy(ctx->y, iv, iv_len);  // copy the IV to the top of the 'y' buff
+    ctx->y[15] = 1;              // start "counting" from 1 (not 0)
+  } else  // if we don't have a 12-byte IV, we GHASH whatever we've been given
+  {
+    memset(work_buf, 0x00, 16);               // clear the working buffer
+    PUT_UINT32_BE(iv_len * 8, work_buf, 12);  // place the IV into buffer
+
+    p = iv;
+    while (iv_len > 0) {
+      use_len = (iv_len < 16) ? iv_len : 16;
+      for (i = 0; i < use_len; i++) ctx->y[i] ^= p[i];
+      gcm_mult(ctx, ctx->y, ctx->y);
+      iv_len -= use_len;
+      p += use_len;
+    }
+    for (i = 0; i < 16; i++) ctx->y[i] ^= work_buf[i];
+    gcm_mult(ctx, ctx->y, ctx->y);
+  }
+  if ((ret = aes_cipher(&ctx->aes_ctx, ctx->y, ctx->base_ectr)) != 0)
+    return (ret);
+
+  ctx->add_len = add_len;
+  p = add;
+  while (add_len > 0) {
+    use_len = (add_len < 16) ? add_len : 16;
+    for (i = 0; i < use_len; i++) ctx->buf[i] ^= p[i];
+    gcm_mult(ctx, ctx->buf, ctx->buf);
+    add_len -= use_len;
+    p += use_len;
+  }
+  return (0);
+}
+
+/******************************************************************************
+ *
+ *  GCM_UPDATE
+ *
+ *  This is called once or more to process bulk plaintext or ciphertext data.
+ *  We give this some number of bytes of input and it returns the same number
+ *  of output bytes. If called multiple times (which is fine) all but the final
+ *  invocation MUST be called with length mod 16 == 0. (Only the final call can
+ *  have a partial block length of < 128 bits.)
+ *
+ ******************************************************************************/
+int gcm_update(gcm_context *ctx,    // pointer to user-provided GCM context
+               size_t length,       // length, in bytes, of data to process
+               const uchar *input,  // pointer to source data
+               uchar *output)       // pointer to destination data
+{
+  int ret;         // our error return if the AES encrypt fails
+  uchar ectr[16];  // counter-mode cipher output for XORing
+  size_t use_len;  // byte count to process, up to 16 bytes
+  size_t i;        // local loop iterator
+
+  ctx->len += length;  // bump the GCM context's running length count
+
+  while (length > 0) {
+    // clamp the length to process at 16 bytes
+    use_len = (length < 16) ? length : 16;
+
+    // increment the context's 128-bit IV||Counter 'y' vector
+    for (i = 16; i > 12; i--)
+      if (++ctx->y[i - 1] != 0) break;
+
+    // encrypt the context's 'y' vector under the established key
+    if ((ret = aes_cipher(&ctx->aes_ctx, ctx->y, ectr)) != 0) return (ret);
+
+    // encrypt or decrypt the input to the output
+    if (ctx->mode == MG_ENCRYPT) {
+      for (i = 0; i < use_len; i++) {
+        // XOR the cipher's ouptut vector (ectr) with our input
+        output[i] = (uchar) (ectr[i] ^ input[i]);
+        // now we mix in our data into the authentication hash.
+        // if we're ENcrypting we XOR in the post-XOR (output)
+        // results, but if we're DEcrypting we XOR in the input
+        // data
+        ctx->buf[i] ^= output[i];
+      }
+    } else {
+      for (i = 0; i < use_len; i++) {
+        // but if we're DEcrypting we XOR in the input data first,
+        // i.e. before saving to ouput data, otherwise if the input
+        // and output buffer are the same (inplace decryption) we
+        // would not get the correct auth tag
 
-  a = (uint32_t *) ctx->in;
-  a[14] = ctx->bits[0];
-  a[15] = ctx->bits[1];
+        ctx->buf[i] ^= input[i];
 
-  mg_md5_transform(ctx->buf, (uint32_t *) ctx->in);
-  mg_byte_reverse((unsigned char *) ctx->buf, 4);
-  memcpy(digest, ctx->buf, 16);
-  memset((char *) ctx, 0, sizeof(*ctx));
-}
-#endif
+        // XOR the cipher's ouptut vector (ectr) with our input
+        output[i] = (uchar) (ectr[i] ^ input[i]);
+      }
+    }
+    gcm_mult(ctx, ctx->buf, ctx->buf);  // perform a GHASH operation
 
-#ifdef MG_ENABLE_LINES
-#line 1 "src/mqtt.c"
-#endif
+    length -= use_len;  // drop the remaining byte count to process
+    input += use_len;   // bump our input pointer forward
+    output += use_len;  // bump our output pointer forward
+  }
+  return (0);
+}
+
+/******************************************************************************
+ *
+ *  GCM_FINISH
+ *
+ *  This is called once after all calls to GCM_UPDATE to finalize the GCM.
+ *  It performs the final GHASH to produce the resulting authentication TAG.
+ *
+ ******************************************************************************/
+int gcm_finish(gcm_context *ctx,  // pointer to user-provided GCM context
+               uchar *tag,        // pointer to buffer which receives the tag
+               size_t tag_len)    // length, in bytes, of the tag-receiving buf
+{
+  uchar work_buf[16];
+  uint64_t orig_len = ctx->len * 8;
+  uint64_t orig_add_len = ctx->add_len * 8;
+  size_t i;
 
+  if (tag_len != 0) memcpy(tag, ctx->base_ectr, tag_len);
 
+  if (orig_len || orig_add_len) {
+    memset(work_buf, 0x00, 16);
 
+    PUT_UINT32_BE((orig_add_len >> 32), work_buf, 0);
+    PUT_UINT32_BE((orig_add_len), work_buf, 4);
+    PUT_UINT32_BE((orig_len >> 32), work_buf, 8);
+    PUT_UINT32_BE((orig_len), work_buf, 12);
 
+    for (i = 0; i < 16; i++) ctx->buf[i] ^= work_buf[i];
+    gcm_mult(ctx, ctx->buf, ctx->buf);
+    for (i = 0; i < tag_len; i++) tag[i] ^= ctx->buf[i];
+  }
+  return (0);
+}
+
+/******************************************************************************
+ *
+ *  GCM_CRYPT_AND_TAG
+ *
+ *  This either encrypts or decrypts the user-provided data and, either
+ *  way, generates an authentication tag of the requested length. It must be
+ *  called with a GCM context whose key has already been set with GCM_SETKEY.
+ *
+ *  The user would typically call this explicitly to ENCRYPT a buffer of data
+ *  and optional associated data, and produce its an authentication tag.
+ *
+ *  To reverse the process the user would typically call the companion
+ *  GCM_AUTH_DECRYPT function to decrypt data and verify a user-provided
+ *  authentication tag.  The GCM_AUTH_DECRYPT function calls this function
+ *  to perform its decryption and tag generation, which it then compares.
+ *
+ ******************************************************************************/
+int gcm_crypt_and_tag(
+    gcm_context *ctx,    // gcm context with key already setup
+    int mode,            // cipher direction: GCM_ENCRYPT or GCM_DECRYPT
+    const uchar *iv,     // pointer to the 12-byte initialization vector
+    size_t iv_len,       // byte length if the IV. should always be 12
+    const uchar *add,    // pointer to the non-ciphered additional data
+    size_t add_len,      // byte length of the additional AEAD data
+    const uchar *input,  // pointer to the cipher data source
+    uchar *output,       // pointer to the cipher data destination
+    size_t length,       // byte length of the cipher data
+    uchar *tag,          // pointer to the tag to be generated
+    size_t tag_len)      // byte length of the tag to be generated
+{                        /*
+                            assuming that the caller has already invoked gcm_setkey to
+                            prepare the gcm context with the keying material, we simply
+                            invoke each of the three GCM sub-functions in turn...
+                         */
+  gcm_start(ctx, mode, iv, iv_len, add, add_len);
+  gcm_update(ctx, length, input, output);
+  gcm_finish(ctx, tag, tag_len);
+  return (0);
+}
+
+/******************************************************************************
+ *
+ *  GCM_ZERO_CTX
+ *
+ *  The GCM context contains both the GCM context and the AES context.
+ *  This includes keying and key-related material which is security-
+ *  sensitive, so it MUST be zeroed after use. This function does that.
+ *
+ ******************************************************************************/
+void gcm_zero_ctx(gcm_context *ctx) {
+  // zero the context originally provided to us
+  memset(ctx, 0, sizeof(gcm_context));
+}
+//
+//  aes-gcm.c
+//  Pods
+//
+//  Created by Markus Kosmal on 20/11/14.
+//
+//
 
+int mg_aes_gcm_encrypt(unsigned char *output,  //
+                       const unsigned char *input, size_t input_length,
+                       const unsigned char *key, const size_t key_len,
+                       const unsigned char *iv, const size_t iv_len,
+                       unsigned char *aead, size_t aead_len, unsigned char *tag,
+                       const size_t tag_len) {
+  int ret = 0;      // our return value
+  gcm_context ctx;  // includes the AES context structure
 
+  gcm_setkey(&ctx, key, (uint) key_len);
 
+  ret = gcm_crypt_and_tag(&ctx, MG_ENCRYPT, iv, iv_len, aead, aead_len, input,
+                          output, input_length, tag, tag_len);
 
-#define MQTT_CLEAN_SESSION 0x02
-#define MQTT_HAS_WILL 0x04
-#define MQTT_WILL_RETAIN 0x20
-#define MQTT_HAS_PASSWORD 0x40
-#define MQTT_HAS_USER_NAME 0x80
+  gcm_zero_ctx(&ctx);
 
-void mg_mqtt_send_header(struct mg_connection *c, uint8_t cmd, uint8_t flags,
-                         uint32_t len) {
-  uint8_t buf[1 + sizeof(len)], *vlen = &buf[1];
-  buf[0] = (uint8_t) ((cmd << 4) | flags);
-  do {
-    *vlen = len % 0x80;
-    len /= 0x80;
-    if (len > 0) *vlen |= 0x80;
-    vlen++;
-  } while (len > 0 && vlen < &buf[sizeof(buf)]);
-  mg_send(c, buf, (size_t) (vlen - buf));
+  return (ret);
 }
 
-static void mg_send_u16(struct mg_connection *c, uint16_t value) {
-  mg_send(c, &value, sizeof(value));
+int mg_aes_gcm_decrypt(unsigned char *output, const unsigned char *input,
+                       size_t input_length, const unsigned char *key,
+                       const size_t key_len, const unsigned char *iv,
+                       const size_t iv_len) {
+  int ret = 0;      // our return value
+  gcm_context ctx;  // includes the AES context structure
+
+  size_t tag_len = 0;
+  unsigned char *tag_buf = NULL;
+
+  gcm_setkey(&ctx, key, (uint) key_len);
+
+  ret = gcm_crypt_and_tag(&ctx, MG_DECRYPT, iv, iv_len, NULL, 0, input, output,
+                          input_length, tag_buf, tag_len);
+
+  gcm_zero_ctx(&ctx);
+
+  return (ret);
 }
+#endif
+// End of aes128 PD
 
-void mg_mqtt_login(struct mg_connection *c, const struct mg_mqtt_opts *opts) {
-  char rnd[10], client_id[21], zero = 0;
-  struct mg_str cid = opts->client_id;
-  uint32_t total_len = 7 + 1 + 2 + 2;
-  uint8_t hdr[8] = {0, 4, 'M', 'Q', 'T', 'T', opts->version, 0};
+#ifdef MG_ENABLE_LINES
+#line 1 "src/tls_builtin.c"
+#endif
 
-  if (cid.len == 0) {
-    mg_random(rnd, sizeof(rnd));
-    mg_hex(rnd, sizeof(rnd), client_id);
-    client_id[sizeof(client_id) - 1] = '\0';
-    cid = mg_str(client_id);
-  }
 
-  if (hdr[6] == 0) hdr[6] = 4;  // If version is not set, use 4 (3.1.1)
-  c->is_mqtt5 = hdr[6] == 5;    // Set version 5 flag
-  hdr[7] = (uint8_t) ((opts->will_qos & 3) << 3);  // Connection flags
-  if (opts->user.len > 0) {
-    total_len += 2 + (uint32_t) opts->user.len;
-    hdr[7] |= MQTT_HAS_USER_NAME;
+
+
+#if MG_TLS == MG_TLS_BUILTIN
+
+/* TLS 1.3 Record Content Type (RFC8446 B.1) */
+#define MG_TLS_CHANGE_CIPHER 20
+#define MG_TLS_ALERT 21
+#define MG_TLS_HANDSHAKE 22
+#define MG_TLS_APP_DATA 23
+#define MG_TLS_HEARTBEAT 24
+
+/* TLS 1.3 Handshake Message Type (RFC8446 B.3) */
+#define MG_TLS_CLIENT_HELLO 1
+#define MG_TLS_SERVER_HELLO 2
+#define MG_TLS_ENCRYPTED_EXTENSIONS 8
+#define MG_TLS_CERTIFICATE 11
+#define MG_TLS_CERTIFICATE_VERIFY 15
+#define MG_TLS_FINISHED 20
+
+// handshake is re-entrant, so we need to keep track of its state state names
+// refer to RFC8446#A.1
+enum mg_tls_hs_state {
+  // Client state machine:
+  MG_TLS_STATE_CLIENT_START,          // Send ClientHello
+  MG_TLS_STATE_CLIENT_WAIT_SH,        // Wait for ServerHello
+  MG_TLS_STATE_CLIENT_WAIT_EE,        // Wait for EncryptedExtensions
+  MG_TLS_STATE_CLIENT_WAIT_CERT,      // Wait for Certificate
+  MG_TLS_STATE_CLIENT_WAIT_CV,        // Wait for CertificateVerify
+  MG_TLS_STATE_CLIENT_WAIT_FINISHED,  // Wait for Finished
+  MG_TLS_STATE_CLIENT_CONNECTED,      // Done
+
+  // Server state machine:
+  MG_TLS_STATE_SERVER_START,       // Wait for ClientHello
+  MG_TLS_STATE_SERVER_NEGOTIATED,  // Wait for Finished
+  MG_TLS_STATE_SERVER_CONNECTED    // Done
+};
+
+// per-connection TLS data
+struct tls_data {
+  enum mg_tls_hs_state state;  // keep track of connection handshake progress
+
+  struct mg_iobuf send;  // For the receive path, we're reusing c->rtls
+  struct mg_iobuf recv;  // While c->rtls contains full records, recv reuses
+                         // the same underlying buffer but points at individual
+                         // decrypted messages
+  uint8_t content_type;  // Last received record content type
+
+  mg_sha256_ctx sha256;  // incremental SHA-256 hash for TLS handshake
+
+  uint32_t sseq;  // server sequence number, used in encryption
+  uint32_t cseq;  // client sequence number, used in decryption
+
+  uint8_t random[32];      // client random from ClientHello
+  uint8_t session_id[32];  // client session ID between the handshake states
+  uint8_t x25519_cli[32];  // client X25519 key between the handshake states
+  uint8_t x25519_sec[32];  // x25519 secret between the handshake states
+
+  int skip_verification;          // perform checks on server certificate?
+  struct mg_str server_cert_der;  // server certificate in DER format
+  uint8_t server_key[32];         // server EC private key
+  char hostname[254];             // server hostname (client extension)
+
+  uint8_t certhash[32];  // certificate message hash
+  uint8_t pubkey[64];    // server EC public key to verify cert
+  uint8_t sighash[32];   // server EC public key to verify cert
+
+  // keys for AES encryption
+  uint8_t handshake_secret[32];
+  uint8_t server_write_key[16];
+  uint8_t server_write_iv[12];
+  uint8_t server_finished_key[32];
+  uint8_t client_write_key[16];
+  uint8_t client_write_iv[12];
+  uint8_t client_finished_key[32];
+};
+
+#define MG_LOAD_BE16(p) ((uint16_t) ((MG_U8P(p)[0] << 8U) | MG_U8P(p)[1]))
+#define MG_LOAD_BE24(p) \
+  ((uint32_t) ((MG_U8P(p)[0] << 16U) | (MG_U8P(p)[1] << 8U) | MG_U8P(p)[2]))
+#define MG_STORE_BE16(p, n)           \
+  do {                                \
+    MG_U8P(p)[0] = ((n) >> 8U) & 255; \
+    MG_U8P(p)[1] = (n) & 255;         \
+  } while (0)
+
+#define TLS_RECHDR_SIZE 5  // 1 byte type, 2 bytes version, 2 bytes length
+#define TLS_MSGHDR_SIZE 4  // 1 byte type, 3 bytes length
+
+#if 1
+static void mg_ssl_key_log(const char *label, uint8_t client_random[32],
+                           uint8_t *secret, size_t secretsz) {
+  (void) label;
+  (void) client_random;
+  (void) secret;
+  (void) secretsz;
+}
+#else
+#include <stdio.h>
+static void mg_ssl_key_log(const char *label, uint8_t client_random[32],
+                           uint8_t *secret, size_t secretsz) {
+  char *keylogfile = getenv("SSLKEYLOGFILE");
+  if (keylogfile == NULL) {
+    return;
   }
-  if (opts->pass.len > 0) {
-    total_len += 2 + (uint32_t) opts->pass.len;
-    hdr[7] |= MQTT_HAS_PASSWORD;
+  FILE *f = fopen(keylogfile, "a");
+  fprintf(f, "%s ", label);
+  for (int i = 0; i < 32; i++) {
+    fprintf(f, "%02x", client_random[i]);
   }
-  if (opts->will_topic.len > 0 && opts->will_message.len > 0) {
-    total_len +=
-        4 + (uint32_t) opts->will_topic.len + (uint32_t) opts->will_message.len;
-    hdr[7] |= MQTT_HAS_WILL;
+  fprintf(f, " ");
+  for (unsigned int i = 0; i < secretsz; i++) {
+    fprintf(f, "%02x", secret[i]);
   }
-  if (opts->clean || cid.len == 0) hdr[7] |= MQTT_CLEAN_SESSION;
-  if (opts->will_retain) hdr[7] |= MQTT_WILL_RETAIN;
-  total_len += (uint32_t) cid.len;
-  if (c->is_mqtt5) total_len += 1U + (hdr[7] & MQTT_HAS_WILL ? 1U : 0);
+  fprintf(f, "\n");
+  fclose(f);
+}
+#endif
 
-  mg_mqtt_send_header(c, MQTT_CMD_CONNECT, 0, total_len);
-  mg_send(c, hdr, sizeof(hdr));
-  // keepalive == 0 means "do not disconnect us!"
-  mg_send_u16(c, mg_htons((uint16_t) opts->keepalive));
+// for derived tls keys we need SHA256([0]*32)
+static uint8_t zeros[32] = {0};
+static uint8_t zeros_sha256_digest[32] = {
+    0xe3, 0xb0, 0xc4, 0x42, 0x98, 0xfc, 0x1c, 0x14, 0x9a, 0xfb, 0xf4,
+    0xc8, 0x99, 0x6f, 0xb9, 0x24, 0x27, 0xae, 0x41, 0xe4, 0x64, 0x9b,
+    0x93, 0x4c, 0xa4, 0x95, 0x99, 0x1b, 0x78, 0x52, 0xb8, 0x55};
 
-  if (c->is_mqtt5) mg_send(c, &zero, sizeof(zero));  // V5 properties
-  mg_send_u16(c, mg_htons((uint16_t) cid.len));
-  mg_send(c, cid.ptr, cid.len);
+// helper to hexdump buffers inline
+static void mg_tls_hexdump(const char *msg, uint8_t *buf, size_t bufsz) {
+  MG_VERBOSE(("%s: %M", msg, mg_print_hex, bufsz, buf));
+}
 
-  if (hdr[7] & MQTT_HAS_WILL) {
-    if (c->is_mqtt5) mg_send(c, &zero, sizeof(zero));  // will props
-    mg_send_u16(c, mg_htons((uint16_t) opts->will_topic.len));
-    mg_send(c, opts->will_topic.ptr, opts->will_topic.len);
-    mg_send_u16(c, mg_htons((uint16_t) opts->will_message.len));
-    mg_send(c, opts->will_message.ptr, opts->will_message.len);
+// helper utilities to parse ASN.1 DER
+struct mg_der_tlv {
+  uint8_t type;
+  uint32_t len;
+  uint8_t *value;
+};
+
+// parse DER into a TLV record
+static int mg_der_to_tlv(uint8_t *der, size_t dersz, struct mg_der_tlv *tlv) {
+  if (dersz < 2) {
+    return -1;
   }
-  if (opts->user.len > 0) {
-    mg_send_u16(c, mg_htons((uint16_t) opts->user.len));
-    mg_send(c, opts->user.ptr, opts->user.len);
+  tlv->type = der[0];
+  tlv->len = der[1];
+  tlv->value = der + 2;
+  if (tlv->len > 0x7f) {
+    uint32_t i, n = tlv->len - 0x80;
+    tlv->len = 0;
+    for (i = 0; i < n; i++) {
+      tlv->len = (tlv->len << 8) | (der[2 + i]);
+    }
+    tlv->value = der + 2 + n;
   }
-  if (opts->pass.len > 0) {
-    mg_send_u16(c, mg_htons((uint16_t) opts->pass.len));
-    mg_send(c, opts->pass.ptr, opts->pass.len);
+  if (der + dersz < tlv->value + tlv->len) {
+    return -1;
   }
+  return 0;
 }
 
-void mg_mqtt_pub(struct mg_connection *c, struct mg_str topic,
-                 struct mg_str data, int qos, bool retain) {
-  uint8_t flags = (uint8_t) (((qos & 3) << 1) | (retain ? 1 : 0)), zero = 0;
-  uint32_t len = 2 + (uint32_t) topic.len + (uint32_t) data.len;
-  MG_DEBUG(("%lu [%.*s] -> [%.*s]", c->id, (int) topic.len, (char *) topic.ptr,
-            (int) data.len, (char *) data.ptr));
-  if (qos > 0) len += 2;
-  if (c->is_mqtt5) len++;
-  mg_mqtt_send_header(c, MQTT_CMD_PUBLISH, flags, len);
-  mg_send_u16(c, mg_htons((uint16_t) topic.len));
-  mg_send(c, topic.ptr, topic.len);
-  if (qos > 0) {
-    if (++c->mgr->mqtt_id == 0) ++c->mgr->mqtt_id;
-    mg_send_u16(c, mg_htons(c->mgr->mqtt_id));
+static int mg_der_find(uint8_t *der, size_t dersz, uint8_t *oid, size_t oidsz,
+                       struct mg_der_tlv *tlv) {
+  uint8_t *p, *end;
+  struct mg_der_tlv child = {0, 0, NULL};
+  if (mg_der_to_tlv(der, dersz, tlv) < 0) {
+    return -1;                  // invalid DER
+  } else if (tlv->type == 6) {  // found OID, check value
+    return (tlv->len == oidsz && memcmp(tlv->value, oid, oidsz) == 0);
+  } else if ((tlv->type & 0x20) == 0) {
+    return 0;  // Primitive, but not OID: not found
+  }
+  // Constructed object: scan children
+  p = tlv->value;
+  end = tlv->value + tlv->len;
+  while (end > p) {
+    int r;
+    mg_der_to_tlv(p, (size_t) (end - p), &child);
+    r = mg_der_find(p, (size_t) (end - p), oid, oidsz, tlv);
+    if (r < 0) return -1;  // error
+    if (r > 0) return 1;   // found OID!
+    p = child.value + child.len;
   }
-  if (c->is_mqtt5) mg_send(c, &zero, sizeof(zero));
-  mg_send(c, data.ptr, data.len);
+  return 0;  // not found
 }
 
-void mg_mqtt_sub(struct mg_connection *c, struct mg_str topic, int qos) {
-  uint8_t qos_ = qos & 3, zero = 0;
-  uint32_t len = 2 + (uint32_t) topic.len + 2 + 1 + (c->is_mqtt5 ? 1 : 0);
-  mg_mqtt_send_header(c, MQTT_CMD_SUBSCRIBE, 2, len);
-  if (++c->mgr->mqtt_id == 0) ++c->mgr->mqtt_id;
-  mg_send_u16(c, mg_htons(c->mgr->mqtt_id));
-  if (c->is_mqtt5) mg_send(c, &zero, sizeof(zero));
-  mg_send_u16(c, mg_htons((uint16_t) topic.len));
-  mg_send(c, topic.ptr, topic.len);
-  mg_send(c, &qos_, sizeof(qos_));
+// Did we receive a full TLS record in the c->rtls buffer?
+static bool mg_tls_got_record(struct mg_connection *c) {
+  return c->rtls.len >= (size_t) TLS_RECHDR_SIZE &&
+         c->rtls.len >=
+             (size_t) (TLS_RECHDR_SIZE + MG_LOAD_BE16(c->rtls.buf + 3));
 }
 
-int mg_mqtt_parse(const uint8_t *buf, size_t len, uint8_t version,
-                  struct mg_mqtt_message *m) {
-  uint8_t lc = 0, *p, *end;
-  uint32_t n = 0, len_len = 0;
+// Remove a single TLS record from the recv buffer
+static void mg_tls_drop_record(struct mg_connection *c) {
+  struct mg_iobuf *rio = &c->rtls;
+  uint16_t n = MG_LOAD_BE16(rio->buf + 3) + TLS_RECHDR_SIZE;
+  mg_iobuf_del(rio, 0, n);
+}
 
-  memset(m, 0, sizeof(*m));
-  m->dgram.ptr = (char *) buf;
-  if (len < 2) return MQTT_INCOMPLETE;
-  m->cmd = (uint8_t) (buf[0] >> 4);
-  m->qos = (buf[0] >> 1) & 3;
+// Remove a single TLS message from decrypted buffer, remove the wrapping
+// record if it was the last message within a record
+static void mg_tls_drop_message(struct mg_connection *c) {
+  uint32_t len;
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  if (tls->recv.len == 0) {
+    return;
+  }
+  len = MG_LOAD_BE24(tls->recv.buf + 1);
+  mg_sha256_update(&tls->sha256, tls->recv.buf, len + TLS_MSGHDR_SIZE);
+  tls->recv.buf += len + TLS_MSGHDR_SIZE;
+  tls->recv.len -= len + TLS_MSGHDR_SIZE;
+  if (tls->recv.len == 0) {
+    mg_tls_drop_record(c);
+  }
+}
 
-  n = len_len = 0;
-  p = (uint8_t *) buf + 1;
-  while ((size_t) (p - buf) < len) {
-    lc = *((uint8_t *) p++);
-    n += (uint32_t) ((lc & 0x7f) << 7 * len_len);
-    len_len++;
-    if (!(lc & 0x80)) break;
-    if (len_len >= 4) return MQTT_MALFORMED;
+// TLS1.3 secret derivation based on the key label
+static void mg_tls_derive_secret(const char *label, uint8_t *key, size_t keysz,
+                                 uint8_t *data, size_t datasz, uint8_t *hash,
+                                 size_t hashsz) {
+  size_t labelsz = strlen(label);
+  uint8_t secret[32];
+  uint8_t packed[256] = {0, (uint8_t) hashsz, (uint8_t) labelsz};
+  // TODO: assert lengths of label, key, data and hash
+  if (labelsz > 0) memmove(packed + 3, label, labelsz);
+  packed[3 + labelsz] = (uint8_t) datasz;
+  if (datasz > 0) memmove(packed + labelsz + 4, data, datasz);
+  packed[4 + labelsz + datasz] = 1;
+
+  mg_hmac_sha256(secret, key, keysz, packed, 5 + labelsz + datasz);
+  memmove(hash, secret, hashsz);
+}
+
+// at this point we have x25519 shared secret, we can generate a set of derived
+// handshake encryption keys
+static void mg_tls_generate_handshake_keys(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+
+  mg_sha256_ctx sha256;
+  uint8_t early_secret[32];
+  uint8_t pre_extract_secret[32];
+  uint8_t hello_hash[32];
+  uint8_t server_hs_secret[32];
+  uint8_t client_hs_secret[32];
+
+  mg_hmac_sha256(early_secret, NULL, 0, zeros, sizeof(zeros));
+  mg_tls_derive_secret("tls13 derived", early_secret, 32, zeros_sha256_digest,
+                       32, pre_extract_secret, 32);
+  mg_hmac_sha256(tls->handshake_secret, pre_extract_secret,
+                 sizeof(pre_extract_secret), tls->x25519_sec,
+                 sizeof(tls->x25519_sec));
+  mg_tls_hexdump("hs secret", tls->handshake_secret, 32);
+
+  // mg_sha256_final is not idempotent, need to copy sha256 context to calculate
+  // the digest
+  memmove(&sha256, &tls->sha256, sizeof(mg_sha256_ctx));
+  mg_sha256_final(hello_hash, &sha256);
+
+  mg_tls_hexdump("hello hash", hello_hash, 32);
+  // derive keys needed for the rest of the handshake
+  mg_tls_derive_secret("tls13 s hs traffic", tls->handshake_secret, 32,
+                       hello_hash, 32, server_hs_secret, 32);
+  mg_tls_derive_secret("tls13 key", server_hs_secret, 32, NULL, 0,
+                       tls->server_write_key, 16);
+  mg_tls_derive_secret("tls13 iv", server_hs_secret, 32, NULL, 0,
+                       tls->server_write_iv, 12);
+  mg_tls_derive_secret("tls13 finished", server_hs_secret, 32, NULL, 0,
+                       tls->server_finished_key, 32);
+
+  mg_tls_derive_secret("tls13 c hs traffic", tls->handshake_secret, 32,
+                       hello_hash, 32, client_hs_secret, 32);
+  mg_tls_derive_secret("tls13 key", client_hs_secret, 32, NULL, 0,
+                       tls->client_write_key, 16);
+  mg_tls_derive_secret("tls13 iv", client_hs_secret, 32, NULL, 0,
+                       tls->client_write_iv, 12);
+  mg_tls_derive_secret("tls13 finished", client_hs_secret, 32, NULL, 0,
+                       tls->client_finished_key, 32);
+
+  mg_tls_hexdump("s hs traffic", server_hs_secret, 32);
+  mg_tls_hexdump("s key", tls->server_write_key, 16);
+  mg_tls_hexdump("s iv", tls->server_write_iv, 12);
+  mg_tls_hexdump("s finished", tls->server_finished_key, 32);
+  mg_tls_hexdump("c hs traffic", client_hs_secret, 32);
+  mg_tls_hexdump("c key", tls->client_write_key, 16);
+  mg_tls_hexdump("c iv", tls->client_write_iv, 16);
+  mg_tls_hexdump("c finished", tls->client_finished_key, 32);
+
+  mg_ssl_key_log("SERVER_HANDSHAKE_TRAFFIC_SECRET", tls->random,
+                 server_hs_secret, 32);
+  mg_ssl_key_log("CLIENT_HANDSHAKE_TRAFFIC_SECRET", tls->random,
+                 client_hs_secret, 32);
+}
+
+static void mg_tls_generate_application_keys(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  uint8_t hash[32];
+  uint8_t premaster_secret[32];
+  uint8_t master_secret[32];
+  uint8_t server_secret[32];
+  uint8_t client_secret[32];
+
+  mg_sha256_ctx sha256;
+  memmove(&sha256, &tls->sha256, sizeof(mg_sha256_ctx));
+  mg_sha256_final(hash, &sha256);
+
+  mg_tls_derive_secret("tls13 derived", tls->handshake_secret, 32,
+                       zeros_sha256_digest, 32, premaster_secret, 32);
+  mg_hmac_sha256(master_secret, premaster_secret, 32, zeros, 32);
+
+  mg_tls_derive_secret("tls13 s ap traffic", master_secret, 32, hash, 32,
+                       server_secret, 32);
+  mg_tls_derive_secret("tls13 key", server_secret, 32, NULL, 0,
+                       tls->server_write_key, 16);
+  mg_tls_derive_secret("tls13 iv", server_secret, 32, NULL, 0,
+                       tls->server_write_iv, 12);
+  mg_tls_derive_secret("tls13 c ap traffic", master_secret, 32, hash, 32,
+                       client_secret, 32);
+  mg_tls_derive_secret("tls13 key", client_secret, 32, NULL, 0,
+                       tls->client_write_key, 16);
+  mg_tls_derive_secret("tls13 iv", client_secret, 32, NULL, 0,
+                       tls->client_write_iv, 12);
+
+  mg_tls_hexdump("s ap traffic", server_secret, 32);
+  mg_tls_hexdump("s key", tls->server_write_key, 16);
+  mg_tls_hexdump("s iv", tls->server_write_iv, 12);
+  mg_tls_hexdump("s finished", tls->server_finished_key, 32);
+  mg_tls_hexdump("c ap traffic", client_secret, 32);
+  mg_tls_hexdump("c key", tls->client_write_key, 16);
+  mg_tls_hexdump("c iv", tls->client_write_iv, 16);
+  mg_tls_hexdump("c finished", tls->client_finished_key, 32);
+  tls->sseq = tls->cseq = 0;
+
+  mg_ssl_key_log("SERVER_TRAFFIC_SECRET_0", tls->random, server_secret, 32);
+  mg_ssl_key_log("CLIENT_TRAFFIC_SECRET_0", tls->random, client_secret, 32);
+}
+
+// AES GCM encryption of the message + put encoded data into the write buffer
+static void mg_tls_encrypt(struct mg_connection *c, const uint8_t *msg,
+                           size_t msgsz, uint8_t msgtype) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  struct mg_iobuf *wio = &tls->send;
+  uint8_t *outmsg;
+  uint8_t *tag;
+  size_t encsz = msgsz + 16 + 1;
+  uint8_t hdr[5] = {MG_TLS_APP_DATA, 0x03, 0x03,
+                    (uint8_t) ((encsz >> 8) & 0xff), (uint8_t) (encsz & 0xff)};
+  uint8_t associated_data[5] = {MG_TLS_APP_DATA, 0x03, 0x03,
+                                (uint8_t) ((encsz >> 8) & 0xff),
+                                (uint8_t) (encsz & 0xff)};
+  uint8_t nonce[12];
+
+  mg_gcm_initialize();
+
+  if (c->is_client) {
+    memmove(nonce, tls->client_write_iv, sizeof(tls->client_write_iv));
+    nonce[8] ^= (uint8_t) ((tls->cseq >> 24) & 255U);
+    nonce[9] ^= (uint8_t) ((tls->cseq >> 16) & 255U);
+    nonce[10] ^= (uint8_t) ((tls->cseq >> 8) & 255U);
+    nonce[11] ^= (uint8_t) ((tls->cseq) & 255U);
+  } else {
+    memmove(nonce, tls->server_write_iv, sizeof(tls->server_write_iv));
+    nonce[8] ^= (uint8_t) ((tls->sseq >> 24) & 255U);
+    nonce[9] ^= (uint8_t) ((tls->sseq >> 16) & 255U);
+    nonce[10] ^= (uint8_t) ((tls->sseq >> 8) & 255U);
+    nonce[11] ^= (uint8_t) ((tls->sseq) & 255U);
   }
-  end = p + n;
-  if ((lc & 0x80) || (end > buf + len)) return MQTT_INCOMPLETE;
-  m->dgram.len = (size_t) (end - buf);
 
-  switch (m->cmd) {
-    case MQTT_CMD_CONNACK:
-      if (end - p < 2) return MQTT_MALFORMED;
-      m->ack = p[1];
-      break;
-    case MQTT_CMD_PUBACK:
-    case MQTT_CMD_PUBREC:
-    case MQTT_CMD_PUBREL:
-    case MQTT_CMD_PUBCOMP:
-    case MQTT_CMD_SUBSCRIBE:
-    case MQTT_CMD_SUBACK:
-    case MQTT_CMD_UNSUBSCRIBE:
-    case MQTT_CMD_UNSUBACK:
-      if (p + 2 > end) return MQTT_MALFORMED;
-      m->id = (uint16_t) ((((uint16_t) p[0]) << 8) | p[1]);
-      p += 2;
-      break;
-    case MQTT_CMD_PUBLISH: {
-      if (p + 2 > end) return MQTT_MALFORMED;
-      m->topic.len = (uint16_t) ((((uint16_t) p[0]) << 8) | p[1]);
-      m->topic.ptr = (char *) p + 2;
-      p += 2 + m->topic.len;
-      if (p > end) return MQTT_MALFORMED;
-      if (m->qos > 0) {
-        if (p + 2 > end) return MQTT_MALFORMED;
-        m->id = (uint16_t) ((((uint16_t) p[0]) << 8) | p[1]);
-        p += 2;
-      }
-      if (p > end) return MQTT_MALFORMED;
-      if (version == 5 && p + 2 < end) p += 1 + p[0];  // Skip options
-      if (p > end) return MQTT_MALFORMED;
-      m->data.ptr = (char *) p;
-      m->data.len = (size_t) (end - p);
-      break;
+  mg_iobuf_add(wio, wio->len, hdr, sizeof(hdr));
+  mg_iobuf_resize(wio, wio->len + encsz);
+  outmsg = wio->buf + wio->len;
+  tag = wio->buf + wio->len + msgsz + 1;
+  memmove(outmsg, msg, msgsz);
+  outmsg[msgsz] = msgtype;
+  if (c->is_client) {
+    mg_aes_gcm_encrypt(outmsg, outmsg, msgsz + 1, tls->client_write_key,
+                       sizeof(tls->client_write_key), nonce, sizeof(nonce),
+                       associated_data, sizeof(associated_data), tag, 16);
+    tls->cseq++;
+  } else {
+    mg_aes_gcm_encrypt(outmsg, outmsg, msgsz + 1, tls->server_write_key,
+                       sizeof(tls->server_write_key), nonce, sizeof(nonce),
+                       associated_data, sizeof(associated_data), tag, 16);
+    tls->sseq++;
+  }
+  wio->len += encsz;
+}
+
+// read an encrypted record, decrypt it in place
+static int mg_tls_recv_record(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  struct mg_iobuf *rio = &c->rtls;
+  uint16_t msgsz;
+  uint8_t *msg;
+  uint8_t nonce[12];
+  int r;
+  if (tls->recv.len > 0) {
+    return 0; /* some data from previous record is still present */
+  }
+  for (;;) {
+    if (!mg_tls_got_record(c)) {
+      return MG_IO_WAIT;
     }
-    default:
+    if (rio->buf[0] == MG_TLS_APP_DATA) {
       break;
+    } else if (rio->buf[0] ==
+               MG_TLS_CHANGE_CIPHER) {  // Skip ChangeCipher messages
+      mg_tls_drop_record(c);
+    } else if (rio->buf[0] == MG_TLS_ALERT) {  // Skip Alerts
+      MG_INFO(("TLS ALERT packet received"));
+      mg_tls_drop_record(c);
+    } else {
+      mg_error(c, "unexpected packet");
+      return -1;
+    }
   }
-  return MQTT_OK;
+
+  mg_gcm_initialize();
+  msgsz = MG_LOAD_BE16(rio->buf + 3);
+  msg = rio->buf + 5;
+  if (c->is_client) {
+    memmove(nonce, tls->server_write_iv, sizeof(tls->server_write_iv));
+    nonce[8] ^= (uint8_t) ((tls->sseq >> 24) & 255U);
+    nonce[9] ^= (uint8_t) ((tls->sseq >> 16) & 255U);
+    nonce[10] ^= (uint8_t) ((tls->sseq >> 8) & 255U);
+    nonce[11] ^= (uint8_t) ((tls->sseq) & 255U);
+    mg_aes_gcm_decrypt(msg, msg, msgsz - 16, tls->server_write_key,
+                       sizeof(tls->server_write_key), nonce, sizeof(nonce));
+    tls->sseq++;
+  } else {
+    memmove(nonce, tls->client_write_iv, sizeof(tls->client_write_iv));
+    nonce[8] ^= (uint8_t) ((tls->cseq >> 24) & 255U);
+    nonce[9] ^= (uint8_t) ((tls->cseq >> 16) & 255U);
+    nonce[10] ^= (uint8_t) ((tls->cseq >> 8) & 255U);
+    nonce[11] ^= (uint8_t) ((tls->cseq) & 255U);
+    mg_aes_gcm_decrypt(msg, msg, msgsz - 16, tls->client_write_key,
+                       sizeof(tls->client_write_key), nonce, sizeof(nonce));
+    tls->cseq++;
+  }
+  r = msgsz - 16 - 1;
+  tls->content_type = msg[msgsz - 16 - 1];
+  tls->recv.buf = msg;
+  tls->recv.size = tls->recv.len = msgsz - 16 - 1;
+  return r;
 }
 
-static void mqtt_cb(struct mg_connection *c, int ev, void *ev_data,
-                    void *fn_data) {
-  if (ev == MG_EV_READ) {
-    for (;;) {
-      uint8_t version = c->is_mqtt5 ? 5 : 4;
-      struct mg_mqtt_message mm;
-      int rc = mg_mqtt_parse(c->recv.buf, c->recv.len, version, &mm);
-      if (rc == MQTT_MALFORMED) {
-        MG_ERROR(("%lu MQTT malformed message", c->id));
-        c->is_closing = 1;
-        break;
-      } else if (rc == MQTT_OK) {
-        MG_VERBOSE(("%lu MQTT CMD %d len %d [%.*s]", c->id, mm.cmd,
-                    (int) mm.dgram.len, (int) mm.data.len, mm.data.ptr));
-        switch (mm.cmd) {
-          case MQTT_CMD_CONNACK:
-            mg_call(c, MG_EV_MQTT_OPEN, &mm.ack);
-            if (mm.ack == 0) {
-              MG_DEBUG(("%lu Connected", c->id));
-            } else {
-              MG_ERROR(("%lu MQTT auth failed, code %d", c->id, mm.ack));
-              c->is_closing = 1;
-            }
-            break;
-          case MQTT_CMD_PUBLISH: {
-            MG_DEBUG(("%lu [%.*s] -> [%.*s]", c->id, (int) mm.topic.len,
-                      mm.topic.ptr, (int) mm.data.len, mm.data.ptr));
-            if (mm.qos > 0) {
-              uint16_t id = mg_htons(mm.id);
-              mg_mqtt_send_header(c, MQTT_CMD_PUBACK, 0, sizeof(id));
-              mg_send(c, &id, sizeof(id));
-            }
-            mg_call(c, MG_EV_MQTT_MSG, &mm);
-            break;
-          }
-        }
-        mg_call(c, MG_EV_MQTT_CMD, &mm);
-        mg_iobuf_del(&c->recv, 0, mm.dgram.len);
-      } else {
-        break;
+static void mg_tls_calc_cert_verify_hash(struct mg_connection *c,
+                                         uint8_t hash[32]) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  uint8_t sig_content[130] = {
+      "                                "
+      "                                "
+      "TLS 1.3, server CertificateVerify\0"};
+  mg_sha256_ctx sha256;
+  memmove(&sha256, &tls->sha256, sizeof(mg_sha256_ctx));
+  mg_sha256_final(sig_content + 98, &sha256);
+
+  mg_sha256_init(&sha256);
+  mg_sha256_update(&sha256, sig_content, sizeof(sig_content));
+  mg_sha256_final(hash, &sha256);
+}
+
+// read and parse ClientHello record
+static int mg_tls_server_recv_hello(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  struct mg_iobuf *rio = &c->rtls;
+  uint8_t session_id_len;
+  uint16_t j;
+  uint16_t cipher_suites_len;
+  uint16_t ext_len;
+  uint8_t *ext;
+  uint16_t msgsz;
+
+  if (!mg_tls_got_record(c)) {
+    return MG_IO_WAIT;
+  }
+  if (rio->buf[0] != MG_TLS_HANDSHAKE || rio->buf[5] != MG_TLS_CLIENT_HELLO) {
+    mg_error(c, "not a client hello packet");
+    return -1;
+  }
+  msgsz = MG_LOAD_BE16(rio->buf + 3);
+  mg_sha256_update(&tls->sha256, rio->buf + 5, msgsz);
+  // store client random
+  memmove(tls->random, rio->buf + 11, sizeof(tls->random));
+  // store session_id
+  session_id_len = rio->buf[43];
+  if (session_id_len == sizeof(tls->session_id)) {
+    memmove(tls->session_id, rio->buf + 44, session_id_len);
+  } else if (session_id_len != 0) {
+    MG_INFO(("bad session id len"));
+  }
+  cipher_suites_len = MG_LOAD_BE16(rio->buf + 44 + session_id_len);
+  ext_len = MG_LOAD_BE16(rio->buf + 48 + session_id_len + cipher_suites_len);
+  ext = rio->buf + 50 + session_id_len + cipher_suites_len;
+  for (j = 0; j < ext_len;) {
+    uint16_t k;
+    uint16_t key_exchange_len;
+    uint8_t *key_exchange;
+    uint16_t n = MG_LOAD_BE16(ext + j + 2);
+    if (ext[j] != 0x00 ||
+        ext[j + 1] != 0x33) {  // not a key share extension, ignore
+      j += (uint16_t) (n + 4);
+      continue;
+    }
+    key_exchange_len = MG_LOAD_BE16(ext + j + 5);
+    key_exchange = ext + j + 6;
+    for (k = 0; k < key_exchange_len;) {
+      uint16_t m = MG_LOAD_BE16(key_exchange + k + 2);
+      if (m == 32 && key_exchange[k] == 0x00 && key_exchange[k + 1] == 0x1d) {
+        memmove(tls->x25519_cli, key_exchange + k + 4, m);
+        mg_tls_drop_record(c);
+        return 0;
       }
+      k += (uint16_t) (m + 4);
     }
+    j += (uint16_t) (n + 4);
   }
-  (void) ev_data;
-  (void) fn_data;
-}
-
-void mg_mqtt_ping(struct mg_connection *nc) {
-  mg_mqtt_send_header(nc, MQTT_CMD_PINGREQ, 0, 0);
-}
-
-void mg_mqtt_pong(struct mg_connection *nc) {
-  mg_mqtt_send_header(nc, MQTT_CMD_PINGRESP, 0, 0);
+  mg_error(c, "bad client hello");
+  return -1;
 }
 
-void mg_mqtt_disconnect(struct mg_connection *nc) {
-  mg_mqtt_send_header(nc, MQTT_CMD_DISCONNECT, 0, 0);
-}
+#define PLACEHOLDER_8B 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X'
+#define PLACEHOLDER_16B PLACEHOLDER_8B, PLACEHOLDER_8B
+#define PLACEHOLDER_32B PLACEHOLDER_16B, PLACEHOLDER_16B
+
+// put ServerHello record into wio buffer
+static void mg_tls_server_send_hello(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  struct mg_iobuf *wio = &tls->send;
+
+  uint8_t msg_server_hello[122] = {
+    // server hello, tls 1.2
+    0x02,
+    0x00,
+    0x00,
+    0x76,
+    0x03,
+    0x03,
+    // random (32 bytes)
+    PLACEHOLDER_32B,
+    // session ID length + session ID (32 bytes)
+    0x20,
+    PLACEHOLDER_32B,
+#if defined(CHACHA20) && CHACHA20
+    // TLS_CHACHA20_POLY1305_SHA256 + no compression
+    0x13,
+    0x03,
+    0x00,
+#else
+    // TLS_AES_128_GCM_SHA256 + no compression
+    0x13,
+    0x01,
+    0x00,
+#endif
+    // extensions + keyshare
+    0x00,
+    0x2e,
+    0x00,
+    0x33,
+    0x00,
+    0x24,
+    0x00,
+    0x1d,
+    0x00,
+    0x20,
+    // x25519 keyshare
+    PLACEHOLDER_32B,
+    // supported versions (tls1.3 == 0x304)
+    0x00,
+    0x2b,
+    0x00,
+    0x02,
+    0x03,
+    0x04
+  };
 
-struct mg_connection *mg_mqtt_connect(struct mg_mgr *mgr, const char *url,
-                                      const struct mg_mqtt_opts *opts,
-                                      mg_event_handler_t fn, void *fn_data) {
-  struct mg_connection *c = mg_connect(mgr, url, fn, fn_data);
-  if (c != NULL) {
-    struct mg_mqtt_opts empty;
-    memset(&empty, 0, sizeof(empty));
-    mg_mqtt_login(c, opts == NULL ? &empty : opts);
-    c->pfn = mqtt_cb;
+  // calculate keyshare
+  uint8_t x25519_pub[X25519_BYTES];
+  uint8_t x25519_prv[X25519_BYTES];
+  mg_random(x25519_prv, sizeof(x25519_prv));
+  mg_tls_x25519(x25519_pub, x25519_prv, X25519_BASE_POINT, 1);
+  mg_tls_x25519(tls->x25519_sec, x25519_prv, tls->x25519_cli, 1);
+  mg_tls_hexdump("s x25519 sec", tls->x25519_sec, sizeof(tls->x25519_sec));
+
+  // fill in the gaps: random + session ID + keyshare
+  memmove(msg_server_hello + 6, tls->random, sizeof(tls->random));
+  memmove(msg_server_hello + 39, tls->session_id, sizeof(tls->session_id));
+  memmove(msg_server_hello + 84, x25519_pub, sizeof(x25519_pub));
+
+  // server hello message
+  mg_iobuf_add(wio, wio->len, "\x16\x03\x03\x00\x7a", 5);
+  mg_iobuf_add(wio, wio->len, msg_server_hello, sizeof(msg_server_hello));
+  mg_sha256_update(&tls->sha256, msg_server_hello, sizeof(msg_server_hello));
+
+  // change cipher message
+  mg_iobuf_add(wio, wio->len, "\x14\x03\x03\x00\x01\x01", 6);
+}
+
+static void mg_tls_server_send_ext(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  // server extensions
+  uint8_t ext[6] = {0x08, 0, 0, 2, 0, 0};
+  mg_sha256_update(&tls->sha256, ext, sizeof(ext));
+  mg_tls_encrypt(c, ext, sizeof(ext), MG_TLS_HANDSHAKE);
+}
+
+static void mg_tls_server_send_cert(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  // server DER certificate (empty)
+  size_t n = tls->server_cert_der.len;
+  uint8_t *cert = (uint8_t *) calloc(1, 13 + n);
+  if (cert == NULL) {
+    mg_error(c, "tls cert oom");
+    return;
   }
-  return c;
-}
+  cert[0] = 0x0b;                                // handshake header
+  cert[1] = (uint8_t) (((n + 9) >> 16) & 255U);  // 3 bytes: payload length
+  cert[2] = (uint8_t) (((n + 9) >> 8) & 255U);
+  cert[3] = (uint8_t) ((n + 9) & 255U);
+  cert[4] = 0;                                   // request context
+  cert[5] = (uint8_t) (((n + 5) >> 16) & 255U);  // 3 bytes: cert (s) length
+  cert[6] = (uint8_t) (((n + 5) >> 8) & 255U);
+  cert[7] = (uint8_t) ((n + 5) & 255U);
+  cert[8] =
+      (uint8_t) (((n) >> 16) & 255U);  // 3 bytes: first (and only) cert len
+  cert[9] = (uint8_t) (((n) >> 8) & 255U);
+  cert[10] = (uint8_t) (n & 255U);
+  // bytes 11+ are certificate in DER format
+  memmove(cert + 11, tls->server_cert_der.buf, n);
+  cert[11 + n] = cert[12 + n] = 0;  // certificate extensions (none)
+  mg_sha256_update(&tls->sha256, cert, 13 + n);
+  mg_tls_encrypt(c, cert, 13 + n, MG_TLS_HANDSHAKE);
+  free(cert);
+}
+
+// type adapter between uECC hash context and our sha256 implementation
+typedef struct SHA256_HashContext {
+  MG_UECC_HashContext uECC;
+  mg_sha256_ctx ctx;
+} SHA256_HashContext;
+
+static void init_SHA256(const MG_UECC_HashContext *base) {
+  SHA256_HashContext *c = (SHA256_HashContext *) base;
+  mg_sha256_init(&c->ctx);
+}
+
+static void update_SHA256(const MG_UECC_HashContext *base,
+                          const uint8_t *message, unsigned message_size) {
+  SHA256_HashContext *c = (SHA256_HashContext *) base;
+  mg_sha256_update(&c->ctx, message, message_size);
+}
+static void finish_SHA256(const MG_UECC_HashContext *base,
+                          uint8_t *hash_result) {
+  SHA256_HashContext *c = (SHA256_HashContext *) base;
+  mg_sha256_final(hash_result, &c->ctx);
+}
+
+static void mg_tls_server_send_cert_verify(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  // server certificate verify packet
+  uint8_t verify[82] = {0x0f, 0x00, 0x00, 0x00, 0x04, 0x03, 0x00, 0x00};
+  size_t sigsz, verifysz = 0;
+  uint8_t hash[32] = {0}, tmp[2 * 32 + 64] = {0};
+  struct SHA256_HashContext ctx = {
+      {&init_SHA256, &update_SHA256, &finish_SHA256, 64, 32, tmp},
+      {{0}, 0, 0, {0}}};
+  int neg1, neg2;
+  uint8_t sig[64] = {0};
+
+  mg_tls_calc_cert_verify_hash(c, (uint8_t *) hash);
+
+  mg_uecc_sign_deterministic(tls->server_key, hash, sizeof(hash), &ctx.uECC,
+                             sig, mg_uecc_secp256r1());
+
+  neg1 = !!(sig[0] & 0x80);
+  neg2 = !!(sig[32] & 0x80);
+  verify[8] = 0x30;  // ASN.1 SEQUENCE
+  verify[9] = (uint8_t) (68 + neg1 + neg2);
+  verify[10] = 0x02;  // ASN.1 INTEGER
+  verify[11] = (uint8_t) (32 + neg1);
+  memmove(verify + 12 + neg1, sig, 32);
+  verify[12 + 32 + neg1] = 0x02;  // ASN.1 INTEGER
+  verify[13 + 32 + neg1] = (uint8_t) (32 + neg2);
+  memmove(verify + 14 + 32 + neg1 + neg2, sig + 32, 32);
+
+  sigsz = (size_t) (70 + neg1 + neg2);
+  verifysz = 8U + sigsz;
+  verify[3] = (uint8_t) (sigsz + 4);
+  verify[7] = (uint8_t) sigsz;
+
+  mg_sha256_update(&tls->sha256, verify, verifysz);
+  mg_tls_encrypt(c, verify, verifysz, MG_TLS_HANDSHAKE);
+}
+
+static void mg_tls_server_send_finish(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  struct mg_iobuf *wio = &tls->send;
+  mg_sha256_ctx sha256;
+  uint8_t hash[32];
+  uint8_t finish[36] = {0x14, 0, 0, 32};
+  memmove(&sha256, &tls->sha256, sizeof(mg_sha256_ctx));
+  mg_sha256_final(hash, &sha256);
+  mg_hmac_sha256(finish + 4, tls->server_finished_key, 32, hash, 32);
+  mg_tls_encrypt(c, finish, sizeof(finish), MG_TLS_HANDSHAKE);
+  mg_io_send(c, wio->buf, wio->len);
+  wio->len = 0;
+
+  mg_sha256_update(&tls->sha256, finish, sizeof(finish));
+}
+
+static int mg_tls_server_recv_finish(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  // we have to backup sha256 value to restore it later, since Finished record
+  // is exceptional and is not supposed to be added to the rolling hash
+  // calculation.
+  mg_sha256_ctx sha256 = tls->sha256;
+  if (mg_tls_recv_record(c) < 0) {
+    return -1;
+  }
+  if (tls->recv.buf[0] != MG_TLS_FINISHED) {
+    mg_error(c, "expected Finish but got msg 0x%02x", tls->recv.buf[0]);
+    return -1;
+  }
+  mg_tls_drop_message(c);
 
-struct mg_connection *mg_mqtt_listen(struct mg_mgr *mgr, const char *url,
-                                     mg_event_handler_t fn, void *fn_data) {
-  struct mg_connection *c = mg_listen(mgr, url, fn, fn_data);
-  if (c != NULL) c->pfn = mqtt_cb, c->pfn_data = mgr;
-  return c;
+  // restore hash
+  tls->sha256 = sha256;
+  return 0;
 }
 
-#ifdef MG_ENABLE_LINES
-#line 1 "src/net.c"
+static void mg_tls_client_send_hello(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  struct mg_iobuf *wio = &tls->send;
+
+  const char *hostname = tls->hostname;
+  size_t hostnamesz = strlen(tls->hostname);
+  uint8_t x25519_pub[X25519_BYTES];
+
+  uint8_t msg_client_hello[162 + 32] = {
+    // TLS Client Hello header reported as TLS1.2 (5)
+    0x16,
+    0x03,
+    0x01,
+    0x00,
+    0xfe,
+    // server hello, tls 1.2 (6)
+    0x01,
+    0x00,
+    0x00,
+    0x8c,
+    0x03,
+    0x03,
+    // random (32 bytes)
+    PLACEHOLDER_32B,
+    // session ID length + session ID (32 bytes)
+    0x20,
+    PLACEHOLDER_32B,
+#if defined(CHACHA20) && CHACHA20
+    // TLS_CHACHA20_POLY1305_SHA256 + no compression
+    0x13,
+    0x03,
+    0x00,
+#else
+    0x00,
+    0x02,  // size = 2 bytes
+    0x13,
+    0x01,  // TLS_AES_128_GCM_SHA256
+    0x01,
+    0x00,  // no compression
 #endif
 
+    // extensions + keyshare
+    0x00,
+    0xfe,
+    // x25519 keyshare
+    0x00,
+    0x33,
+    0x00,
+    0x26,
+    0x00,
+    0x24,
+    0x00,
+    0x1d,
+    0x00,
+    0x20,
+    PLACEHOLDER_32B,
+    // supported groups (x25519)
+    0x00,
+    0x0a,
+    0x00,
+    0x04,
+    0x00,
+    0x02,
+    0x00,
+    0x1d,
+    // supported versions (tls1.3 == 0x304)
+    0x00,
+    0x2b,
+    0x00,
+    0x03,
+    0x02,
+    0x03,
+    0x04,
+    // session ticket (none)
+    0x00,
+    0x23,
+    0x00,
+    0x00,
+    // signature algorithms (we don't care, so list all the common ones)
+    0x00,
+    0x0d,
+    0x00,
+    0x24,
+    0x00,
+    0x22,
+    0x04,
+    0x03,
+    0x05,
+    0x03,
+    0x06,
+    0x03,
+    0x08,
+    0x07,
+    0x08,
+    0x08,
+    0x08,
+    0x1a,
+    0x08,
+    0x1b,
+    0x08,
+    0x1c,
+    0x08,
+    0x09,
+    0x08,
+    0x0a,
+    0x08,
+    0x0b,
+    0x08,
+    0x04,
+    0x08,
+    0x05,
+    0x08,
+    0x06,
+    0x04,
+    0x01,
+    0x05,
+    0x01,
+    0x06,
+    0x01,
+    // server name
+    0x00,
+    0x00,
+    0x00,
+    0xfe,
+    0x00,
+    0xfe,
+    0x00,
+    0x00,
+    0xfe
+  };
 
+  // patch ClientHello with correct hostname length + offset:
+  MG_STORE_BE16(msg_client_hello + 3, hostnamesz + 189);
+  MG_STORE_BE16(msg_client_hello + 7, hostnamesz + 185);
+  MG_STORE_BE16(msg_client_hello + 82, hostnamesz + 110);
+  MG_STORE_BE16(msg_client_hello + 187, hostnamesz + 5);
+  MG_STORE_BE16(msg_client_hello + 189, hostnamesz + 3);
+  MG_STORE_BE16(msg_client_hello + 192, hostnamesz);
+
+  // calculate keyshare
+  mg_random(tls->x25519_cli, sizeof(tls->x25519_cli));
+  mg_tls_x25519(x25519_pub, tls->x25519_cli, X25519_BASE_POINT, 1);
+
+  // fill in the gaps: random + session ID + keyshare
+  mg_random(tls->session_id, sizeof(tls->session_id));
+  mg_random(tls->random, sizeof(tls->random));
+  memmove(msg_client_hello + 11, tls->random, sizeof(tls->random));
+  memmove(msg_client_hello + 44, tls->session_id, sizeof(tls->session_id));
+  memmove(msg_client_hello + 94, x25519_pub, sizeof(x25519_pub));
+
+  // server hello message
+  mg_iobuf_add(wio, wio->len, msg_client_hello, sizeof(msg_client_hello));
+  mg_iobuf_add(wio, wio->len, hostname, strlen(hostname));
+  mg_sha256_update(&tls->sha256, msg_client_hello + 5,
+                   sizeof(msg_client_hello) - 5);
+  mg_sha256_update(&tls->sha256, (uint8_t *) hostname, strlen(hostname));
+
+  // change cipher message
+  mg_iobuf_add(wio, wio->len, (const char *) "\x14\x03\x03\x00\x01\x01", 6);
+  mg_io_send(c, wio->buf, wio->len);
+  wio->len = 0;
+}
+
+static int mg_tls_client_recv_hello(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  struct mg_iobuf *rio = &c->rtls;
+  uint16_t msgsz;
+  uint8_t *ext;
+  uint16_t ext_len;
+  int j;
+
+  if (!mg_tls_got_record(c)) {
+    return MG_IO_WAIT;
+  }
+  if (rio->buf[0] != MG_TLS_HANDSHAKE || rio->buf[5] != MG_TLS_SERVER_HELLO) {
+    if (rio->buf[0] == MG_TLS_ALERT && rio->len >= 7) {
+      mg_error(c, "tls alert %d", rio->buf[6]);
+      return -1;
+    }
+    MG_INFO(("got packet type 0x%02x/0x%02x", rio->buf[0], rio->buf[5]));
+    mg_error(c, "not a server hello packet");
+    return -1;
+  }
 
-
-
-
-
-size_t mg_vprintf(struct mg_connection *c, const char *fmt, va_list *ap) {
-  size_t old = c->send.len;
-  mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, ap);
-  return c->send.len - old;
-}
-
-size_t mg_printf(struct mg_connection *c, const char *fmt, ...) {
-  size_t len = 0;
-  va_list ap;
-  va_start(ap, fmt);
-  len = mg_vprintf(c, fmt, &ap);
-  va_end(ap);
-  return len;
-}
-
-static bool mg_atonl(struct mg_str str, struct mg_addr *addr) {
-  if (mg_vcasecmp(&str, "localhost") != 0) return false;
-  addr->ip = mg_htonl(0x7f000001);
-  addr->is_ip6 = false;
-  return true;
+  msgsz = MG_LOAD_BE16(rio->buf + 3);
+  mg_sha256_update(&tls->sha256, rio->buf + 5, msgsz);
+
+  ext_len = MG_LOAD_BE16(rio->buf + 5 + 39 + 32 + 3);
+  ext = rio->buf + 5 + 39 + 32 + 3 + 2;
+
+  for (j = 0; j < ext_len;) {
+    uint16_t ext_type = MG_LOAD_BE16(ext + j);
+    uint16_t ext_len2 = MG_LOAD_BE16(ext + j + 2);
+    uint16_t group;
+    uint8_t *key_exchange;
+    uint16_t key_exchange_len;
+    if (ext_type != 0x0033) {  // not a key share extension, ignore
+      j += (uint16_t) (ext_len2 + 4);
+      continue;
+    }
+    group = MG_LOAD_BE16(ext + j + 4);
+    if (group != 0x001d) {
+      mg_error(c, "bad key exchange group");
+      return -1;
+    }
+    key_exchange_len = MG_LOAD_BE16(ext + j + 6);
+    key_exchange = ext + j + 8;
+    if (key_exchange_len != 32) {
+      mg_error(c, "bad key exchange length");
+      return -1;
+    }
+    mg_tls_x25519(tls->x25519_sec, tls->x25519_cli, key_exchange, 1);
+    mg_tls_hexdump("c x25519 sec", tls->x25519_sec, 32);
+    mg_tls_drop_record(c);
+    /* generate handshake keys */
+    mg_tls_generate_handshake_keys(c);
+    return 0;
+  }
+  mg_error(c, "bad client hello");
+  return -1;
 }
 
-static bool mg_atone(struct mg_str str, struct mg_addr *addr) {
-  if (str.len > 0) return false;
-  addr->ip = 0;
-  addr->is_ip6 = false;
-  return true;
+static int mg_tls_client_recv_ext(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  if (mg_tls_recv_record(c) < 0) {
+    return -1;
+  }
+  if (tls->recv.buf[0] != MG_TLS_ENCRYPTED_EXTENSIONS) {
+    mg_error(c, "expected server extensions but got msg 0x%02x",
+             tls->recv.buf[0]);
+    return -1;
+  }
+  mg_tls_drop_message(c);
+  return 0;
 }
 
-static bool mg_aton4(struct mg_str str, struct mg_addr *addr) {
-  uint8_t data[4] = {0, 0, 0, 0};
-  size_t i, num_dots = 0;
-  for (i = 0; i < str.len; i++) {
-    if (str.ptr[i] >= '0' && str.ptr[i] <= '9') {
-      int octet = data[num_dots] * 10 + (str.ptr[i] - '0');
-      if (octet > 255) return false;
-      data[num_dots] = (uint8_t) octet;
-    } else if (str.ptr[i] == '.') {
-      if (num_dots >= 3 || i == 0 || str.ptr[i - 1] == '.') return false;
-      num_dots++;
-    } else {
-      return false;
-    }
+static int mg_tls_client_recv_cert(struct mg_connection *c) {
+  uint8_t *cert;
+  uint32_t certsz;
+  struct mg_der_tlv oid, pubkey, seq, subj;
+  int subj_match = 0;
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  if (mg_tls_recv_record(c) < 0) {
+    return -1;
+  }
+  if (tls->recv.buf[0] != MG_TLS_CERTIFICATE) {
+    mg_error(c, "expected server certificate but got msg 0x%02x",
+             tls->recv.buf[0]);
+    return -1;
+  }
+  if (tls->skip_verification) {
+    mg_tls_drop_message(c);
+    return 0;
   }
-  if (num_dots != 3 || str.ptr[i - 1] == '.') return false;
-  memcpy(&addr->ip, data, sizeof(data));
-  addr->is_ip6 = false;
-  return true;
-}
 
-static bool mg_v4mapped(struct mg_str str, struct mg_addr *addr) {
-  int i;
-  if (str.len < 14) return false;
-  if (str.ptr[0] != ':' || str.ptr[1] != ':' || str.ptr[6] != ':') return false;
-  for (i = 2; i < 6; i++) {
-    if (str.ptr[i] != 'f' && str.ptr[i] != 'F') return false;
+  if (tls->recv.len < 11) {
+    mg_error(c, "certificate list too short");
+    return -1;
   }
-  if (!mg_aton4(mg_str_n(&str.ptr[7], str.len - 7), addr)) return false;
-  memset(addr->ip6, 0, sizeof(addr->ip6));
-  addr->ip6[10] = addr->ip6[11] = 255;
-  memcpy(&addr->ip6[12], &addr->ip, 4);
-  addr->is_ip6 = true;
-  return true;
-}
 
-static bool mg_aton6(struct mg_str str, struct mg_addr *addr) {
-  size_t i, j = 0, n = 0, dc = 42;
-  if (str.len > 2 && str.ptr[0] == '[') str.ptr++, str.len -= 2;
-  if (mg_v4mapped(str, addr)) return true;
-  for (i = 0; i < str.len; i++) {
-    if ((str.ptr[i] >= '0' && str.ptr[i] <= '9') ||
-        (str.ptr[i] >= 'a' && str.ptr[i] <= 'f') ||
-        (str.ptr[i] >= 'A' && str.ptr[i] <= 'F')) {
-      unsigned long val;
-      if (i > j + 3) return false;
-      // MG_DEBUG(("%zu %zu [%.*s]", i, j, (int) (i - j + 1), &str.ptr[j]));
-      val = mg_unhexn(&str.ptr[j], i - j + 1);
-      addr->ip6[n] = (uint8_t) ((val >> 8) & 255);
-      addr->ip6[n + 1] = (uint8_t) (val & 255);
-    } else if (str.ptr[i] == ':') {
-      j = i + 1;
-      if (i > 0 && str.ptr[i - 1] == ':') {
-        dc = n;  // Double colon
-        if (i > 1 && str.ptr[i - 2] == ':') return false;
-      } else if (i > 0) {
-        n += 2;
+  cert = tls->recv.buf + 11;
+  certsz = MG_LOAD_BE24(tls->recv.buf + 8);
+  if (certsz > tls->recv.len - 11) {
+    mg_error(c, "certificate too long: %d vs %d", certsz, tls->recv.len - 11);
+    return -1;
+  }
+
+  do {
+    // secp256r1 public key
+    if (mg_der_find(cert, certsz,
+                    (uint8_t *) "\x2A\x86\x48\xCE\x3D\x03\x01\x07", 8,
+                    &oid) < 0) {
+      mg_error(c, "certificate secp256r1 public key OID not found");
+      return -1;
+    }
+    if (mg_der_to_tlv(oid.value + oid.len,
+                      (size_t) (cert + certsz - (oid.value + oid.len)),
+                      &pubkey) < 0) {
+      mg_error(c, "certificate secp256r1 public key not found");
+      return -1;
+    }
+
+    // expect BIT STRING, unpadded, uncompressed: [0]+[4]+32+32 content bytes
+    if (pubkey.type != 3 || pubkey.len != 66 || pubkey.value[0] != 0 ||
+        pubkey.value[1] != 4) {
+      mg_error(c, "unsupported public key bitstring encoding");
+      return -1;
+    }
+    memmove(tls->pubkey, pubkey.value + 2, pubkey.len - 2);
+  } while (0);
+
+  // Subject Alternative Names
+  do {
+    if (mg_der_find(cert, certsz, (uint8_t *) "\x55\x1d\x11", 3, &oid) < 0) {
+      mg_error(c, "certificate does not contain subject alternative names");
+      return -1;
+    }
+    if (mg_der_to_tlv(oid.value + oid.len,
+                      (size_t) (cert + certsz - (oid.value + oid.len)),
+                      &seq) < 0) {
+      mg_error(c, "certificate subject alternative names not found");
+      return -1;
+    }
+    if (mg_der_to_tlv(seq.value, seq.len, &seq) < 0) {
+      mg_error(
+          c,
+          "certificate subject alternative names is not a constructed object");
+      return -1;
+    }
+    MG_VERBOSE(("verify hostname %s", tls->hostname));
+    while (seq.len > 0) {
+      if (mg_der_to_tlv(seq.value, seq.len, &subj) < 0) {
+        mg_error(c, "bad subject alternative name");
+        return -1;
       }
-      if (n > 14) return false;
-      addr->ip6[n] = addr->ip6[n + 1] = 0;  // For trailing ::
-    } else {
-      return false;
+      MG_VERBOSE(("subj=%.*s", subj.len, subj.value));
+      if (mg_match(mg_str((const char *) tls->hostname),
+                   mg_str_n((const char *) subj.value, subj.len), NULL)) {
+        subj_match = 1;
+        break;
+      }
+      seq.len = (uint32_t) (seq.value + seq.len - (subj.value + subj.len));
+      seq.value = subj.value + subj.len;
+    }
+    if (!subj_match) {
+      mg_error(c, "certificate did not match the hostname");
+      return -1;
     }
+  } while (0);
+
+  mg_tls_drop_message(c);
+  mg_tls_calc_cert_verify_hash(c, tls->sighash);
+  return 0;
+}
+
+static int mg_tls_client_recv_cert_verify(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  if (mg_tls_recv_record(c) < 0) {
+    return -1;
   }
-  if (n < 14 && dc == 42) return false;
-  if (n < 14) {
-    memmove(&addr->ip6[dc + (14 - n)], &addr->ip6[dc], n - dc + 2);
-    memset(&addr->ip6[dc], 0, 14 - n);
+  if (tls->recv.buf[0] != MG_TLS_CERTIFICATE_VERIFY) {
+    mg_error(c, "expected server certificate verify but got msg 0x%02x",
+             tls->recv.buf[0]);
+    return -1;
+  }
+  // Ignore CertificateVerify is strict checks are not required
+  if (tls->skip_verification) {
+    mg_tls_drop_message(c);
+    return 0;
   }
-  addr->is_ip6 = true;
-  return true;
-}
 
-bool mg_aton(struct mg_str str, struct mg_addr *addr) {
-  // MG_INFO(("[%.*s]", (int) str.len, str.ptr));
-  return mg_atone(str, addr) || mg_atonl(str, addr) || mg_aton4(str, addr) ||
-         mg_aton6(str, addr);
+  // Extract certificate signature and verify it using pubkey and sighash
+  do {
+    uint8_t sig[64];
+    struct mg_der_tlv seq, a, b;
+    if (mg_der_to_tlv(tls->recv.buf + 8, tls->recv.len - 8, &seq) < 0) {
+      mg_error(c, "verification message is not an ASN.1 DER sequence");
+      return -1;
+    }
+    if (mg_der_to_tlv(seq.value, seq.len, &a) < 0) {
+      mg_error(c, "missing first part of the signature");
+      return -1;
+    }
+    if (mg_der_to_tlv(a.value + a.len, seq.len - a.len, &b) < 0) {
+      mg_error(c, "missing second part of the signature");
+      return -1;
+    }
+    // Integers may be padded with zeroes
+    if (a.len > 32) {
+      a.value = a.value + (a.len - 32);
+      a.len = 32;
+    }
+    if (b.len > 32) {
+      b.value = b.value + (b.len - 32);
+      b.len = 32;
+    }
+
+    memmove(sig, a.value, a.len);
+    memmove(sig + 32, b.value, b.len);
+
+    if (mg_uecc_verify(tls->pubkey, tls->sighash, sizeof(tls->sighash), sig,
+                       mg_uecc_secp256r1()) != 1) {
+      mg_error(c, "failed to verify certificate");
+      return -1;
+    }
+  } while (0);
+
+  mg_tls_drop_message(c);
+  return 0;
 }
 
-struct mg_connection *mg_alloc_conn(struct mg_mgr *mgr) {
-  struct mg_connection *c =
-      (struct mg_connection *) calloc(1, sizeof(*c) + mgr->extraconnsize);
-  if (c != NULL) {
-    c->mgr = mgr;
-    c->send.align = c->recv.align = MG_IO_SIZE;
-    c->id = ++mgr->nextid;
+static int mg_tls_client_recv_finish(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  if (mg_tls_recv_record(c) < 0) {
+    return -1;
   }
-  return c;
+  if (tls->recv.buf[0] != MG_TLS_FINISHED) {
+    mg_error(c, "expected server finished but got msg 0x%02x",
+             tls->recv.buf[0]);
+    return -1;
+  }
+  mg_tls_drop_message(c);
+  return 0;
 }
 
-void mg_close_conn(struct mg_connection *c) {
-  mg_resolve_cancel(c);  // Close any pending DNS query
-  LIST_DELETE(struct mg_connection, &c->mgr->conns, c);
-  if (c == c->mgr->dns4.c) c->mgr->dns4.c = NULL;
-  if (c == c->mgr->dns6.c) c->mgr->dns6.c = NULL;
-  // Order of operations is important. `MG_EV_CLOSE` event must be fired
-  // before we deallocate received data, see #1331
-  mg_call(c, MG_EV_CLOSE, NULL);
-  MG_DEBUG(("%lu %p closed", c->id, c->fd));
-
-  mg_tls_free(c);
-  mg_iobuf_free(&c->recv);
-  mg_iobuf_free(&c->send);
-  memset(c, 0, sizeof(*c));
-  free(c);
+static void mg_tls_client_send_finish(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  struct mg_iobuf *wio = &tls->send;
+  mg_sha256_ctx sha256;
+  uint8_t hash[32];
+  uint8_t finish[36] = {0x14, 0, 0, 32};
+  memmove(&sha256, &tls->sha256, sizeof(mg_sha256_ctx));
+  mg_sha256_final(hash, &sha256);
+  mg_hmac_sha256(finish + 4, tls->client_finished_key, 32, hash, 32);
+  mg_tls_encrypt(c, finish, sizeof(finish), MG_TLS_HANDSHAKE);
+  mg_io_send(c, wio->buf, wio->len);
+  wio->len = 0;
+}
+
+static void mg_tls_client_handshake(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  switch (tls->state) {
+    case MG_TLS_STATE_CLIENT_START:
+      mg_tls_client_send_hello(c);
+      tls->state = MG_TLS_STATE_CLIENT_WAIT_SH;
+      // Fallthrough
+    case MG_TLS_STATE_CLIENT_WAIT_SH:
+      if (mg_tls_client_recv_hello(c) < 0) {
+        break;
+      }
+      tls->state = MG_TLS_STATE_CLIENT_WAIT_EE;
+      // Fallthrough
+    case MG_TLS_STATE_CLIENT_WAIT_EE:
+      if (mg_tls_client_recv_ext(c) < 0) {
+        break;
+      }
+      tls->state = MG_TLS_STATE_CLIENT_WAIT_CERT;
+      // Fallthrough
+    case MG_TLS_STATE_CLIENT_WAIT_CERT:
+      if (mg_tls_client_recv_cert(c) < 0) {
+        break;
+      }
+      tls->state = MG_TLS_STATE_CLIENT_WAIT_CV;
+      // Fallthrough
+    case MG_TLS_STATE_CLIENT_WAIT_CV:
+      if (mg_tls_client_recv_cert_verify(c) < 0) {
+        break;
+      }
+      tls->state = MG_TLS_STATE_CLIENT_WAIT_FINISHED;
+      // Fallthrough
+    case MG_TLS_STATE_CLIENT_WAIT_FINISHED:
+      if (mg_tls_client_recv_finish(c) < 0) {
+        break;
+      }
+      mg_tls_client_send_finish(c);
+      mg_tls_generate_application_keys(c);
+      tls->state = MG_TLS_STATE_CLIENT_CONNECTED;
+      c->is_tls_hs = 0;
+      break;
+    default: mg_error(c, "unexpected client state: %d", tls->state); break;
+  }
 }
 
-struct mg_connection *mg_connect(struct mg_mgr *mgr, const char *url,
-                                 mg_event_handler_t fn, void *fn_data) {
-  struct mg_connection *c = NULL;
-  if (url == NULL || url[0] == '\0') {
-    MG_ERROR(("null url"));
-  } else if ((c = mg_alloc_conn(mgr)) == NULL) {
-    MG_ERROR(("OOM"));
-  } else {
-    LIST_ADD_HEAD(struct mg_connection, &mgr->conns, c);
-    c->is_udp = (strncmp(url, "udp:", 4) == 0);
-    c->fd = (void *) (size_t) MG_INVALID_SOCKET;
-    c->fn = fn;
-    c->is_client = true;
-    c->fn_data = fn_data;
-    MG_DEBUG(("%lu %p %s", c->id, c->fd, url));
-    mg_call(c, MG_EV_OPEN, NULL);
-    mg_resolve(c, url);
+static void mg_tls_server_handshake(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  switch (tls->state) {
+    case MG_TLS_STATE_SERVER_START:
+      if (mg_tls_server_recv_hello(c) < 0) {
+        return;
+      }
+      mg_tls_server_send_hello(c);
+      mg_tls_generate_handshake_keys(c);
+      mg_tls_server_send_ext(c);
+      mg_tls_server_send_cert(c);
+      mg_tls_server_send_cert_verify(c);
+      mg_tls_server_send_finish(c);
+      tls->state = MG_TLS_STATE_SERVER_NEGOTIATED;
+      // fallthrough
+    case MG_TLS_STATE_SERVER_NEGOTIATED:
+      if (mg_tls_server_recv_finish(c) < 0) {
+        return;
+      }
+      mg_tls_generate_application_keys(c);
+      tls->state = MG_TLS_STATE_SERVER_CONNECTED;
+      c->is_tls_hs = 0;
+      return;
+    default: mg_error(c, "unexpected server state: %d", tls->state); break;
   }
-  return c;
 }
 
-struct mg_connection *mg_listen(struct mg_mgr *mgr, const char *url,
-                                mg_event_handler_t fn, void *fn_data) {
-  struct mg_connection *c = NULL;
-  if ((c = mg_alloc_conn(mgr)) == NULL) {
-    MG_ERROR(("OOM %s", url));
-  } else if (!mg_open_listener(c, url)) {
-    MG_ERROR(("Failed: %s, errno %d", url, errno));
-    free(c);
-    c = NULL;
+void mg_tls_handshake(struct mg_connection *c) {
+  if (c->is_client) {
+    mg_tls_client_handshake(c);
   } else {
-    c->is_listening = 1;
-    c->is_udp = strncmp(url, "udp:", 4) == 0;
-    LIST_ADD_HEAD(struct mg_connection, &mgr->conns, c);
-    c->fn = fn;
-    c->fn_data = fn_data;
-    mg_call(c, MG_EV_OPEN, NULL);
-    MG_DEBUG(("%lu %p %s", c->id, c->fd, url));
+    mg_tls_server_handshake(c);
   }
-  return c;
 }
 
-struct mg_connection *mg_wrapfd(struct mg_mgr *mgr, int fd,
-                                mg_event_handler_t fn, void *fn_data) {
-  struct mg_connection *c = mg_alloc_conn(mgr);
-  if (c != NULL) {
-    c->fd = (void *) (size_t) fd;
-    c->fn = fn;
-    c->fn_data = fn_data;
-    MG_EPOLL_ADD(c);
-    mg_call(c, MG_EV_OPEN, NULL);
-    LIST_ADD_HEAD(struct mg_connection, &mgr->conns, c);
+static int mg_parse_pem(const struct mg_str pem, const struct mg_str label,
+                        struct mg_str *der) {
+  size_t n = 0, m = 0;
+  char *s;
+  const char *c;
+  struct mg_str caps[5];
+  if (!mg_match(pem, mg_str("#-----BEGIN #-----#-----END #-----#"), caps)) {
+    der->buf = mg_mprintf("%.*s", pem.len, pem.buf);
+    der->len = pem.len;
+    return 0;
+  }
+  if (mg_strcmp(caps[1], label) != 0 || mg_strcmp(caps[3], label) != 0) {
+    return -1;  // bad label
+  }
+  if ((s = (char *) calloc(1, caps[2].len)) == NULL) {
+    return -1;
   }
-  return c;
-}
 
-struct mg_timer *mg_timer_add(struct mg_mgr *mgr, uint64_t milliseconds,
-                              unsigned flags, void (*fn)(void *), void *arg) {
-  struct mg_timer *t = (struct mg_timer *) calloc(1, sizeof(*t));
-  if (t != NULL) {
-    mg_timer_init(&mgr->timers, t, milliseconds, flags, fn, arg);
-    t->id = mgr->timerid++;
+  for (c = caps[2].buf; c < caps[2].buf + caps[2].len; c++) {
+    if (*c == ' ' || *c == '\n' || *c == '\r' || *c == '\t') {
+      continue;
+    }
+    s[n++] = *c;
   }
-  return t;
+  m = mg_base64_decode(s, n, s, n);
+  if (m == 0) {
+    free(s);
+    return -1;
+  }
+  der->buf = s;
+  der->len = m;
+  return 0;
 }
 
-void mg_mgr_free(struct mg_mgr *mgr) {
-  struct mg_connection *c;
-  struct mg_timer *tmp, *t = mgr->timers;
-  while (t != NULL) tmp = t->next, free(t), t = tmp;
-  mgr->timers = NULL;  // Important. Next call to poll won't touch timers
-  for (c = mgr->conns; c != NULL; c = c->next) c->is_closing = 1;
-  mg_mgr_poll(mgr, 0);
-#if MG_ENABLE_FREERTOS_TCP
-  FreeRTOS_DeleteSocketSet(mgr->ss);
-#endif
-  MG_DEBUG(("All connections closed"));
-#if MG_ENABLE_EPOLL
-  if (mgr->epoll_fd >= 0) close(mgr->epoll_fd), mgr->epoll_fd = -1;
-#endif
-}
+void mg_tls_init(struct mg_connection *c, const struct mg_tls_opts *opts) {
+  struct mg_str key;
+  struct tls_data *tls = (struct tls_data *) calloc(1, sizeof(struct tls_data));
+  if (tls == NULL) {
+    mg_error(c, "tls oom");
+    return;
+  }
 
-void mg_mgr_init(struct mg_mgr *mgr) {
-  memset(mgr, 0, sizeof(*mgr));
-#if MG_ENABLE_EPOLL
-  if ((mgr->epoll_fd = epoll_create1(0)) < 0) MG_ERROR(("epoll: %d", errno));
-#else
-  mgr->epoll_fd = -1;
-#endif
-#if MG_ARCH == MG_ARCH_WIN32 && MG_ENABLE_WINSOCK
-  // clang-format off
-  { WSADATA data; WSAStartup(MAKEWORD(2, 2), &data); }
-  // clang-format on
-#elif MG_ENABLE_FREERTOS_TCP
-  mgr->ss = FreeRTOS_CreateSocketSet();
-#elif defined(__unix) || defined(__unix__) || defined(__APPLE__)
-  // Ignore SIGPIPE signal, so if client cancels the request, it
-  // won't kill the whole process.
-  signal(SIGPIPE, SIG_IGN);
-#endif
-  mgr->dnstimeout = 3000;
-  mgr->dns4.url = "udp://8.8.8.8:53";
-  mgr->dns6.url = "udp://[2001:4860:4860::8888]:53";
-}
+  tls->state =
+      c->is_client ? MG_TLS_STATE_CLIENT_START : MG_TLS_STATE_SERVER_START;
 
-#ifdef MG_ENABLE_LINES
-#line 1 "src/rpc.c"
-#endif
+  tls->skip_verification = opts->skip_verification;
+  tls->send.align = MG_IO_SIZE;
 
+  c->tls = tls;
+  c->is_tls = c->is_tls_hs = 1;
+  mg_sha256_init(&tls->sha256);
 
-void mg_rpc_add(struct mg_rpc **head, struct mg_str method,
-                void (*fn)(struct mg_rpc_req *), void *fn_data) {
-  struct mg_rpc *rpc = (struct mg_rpc *) calloc(1, sizeof(*rpc));
-  if (rpc != NULL) {
-    rpc->method = mg_strdup(method), rpc->fn = fn, rpc->fn_data = fn_data;
-    rpc->next = *head, *head = rpc;
+  // save hostname (client extension)
+  if (opts->name.len > 0) {
+    if (opts->name.len >= sizeof(tls->hostname) - 1) {
+      mg_error(c, "hostname too long");
+    }
+    strncpy((char *) tls->hostname, opts->name.buf, sizeof(tls->hostname) - 1);
+    tls->hostname[opts->name.len] = 0;
   }
-}
 
-void mg_rpc_del(struct mg_rpc **head, void (*fn)(struct mg_rpc_req *)) {
-  struct mg_rpc *r;
-  while ((r = *head) != NULL) {
-    if (r->fn == fn || fn == NULL) {
-      *head = r->next;
-      free((void *) r->method.ptr);
-      free(r);
-    } else {
-      head = &(*head)->next;
-    }
+  if (c->is_client) {
+    tls->server_cert_der.buf = NULL;
+    return;
   }
-}
 
-static void mg_rpc_call(struct mg_rpc_req *r, struct mg_str method) {
-  struct mg_rpc *h = r->head == NULL ? NULL : *r->head;
-  while (h != NULL && !mg_match(method, h->method, NULL)) h = h->next;
-  if (h != NULL) {
-    r->rpc = h;
-    h->fn(r);
+  // parse PEM or DER certificate
+  if (mg_parse_pem(opts->cert, mg_str_s("CERTIFICATE"), &tls->server_cert_der) <
+      0) {
+    MG_ERROR(("Failed to load certificate"));
+    return;
+  }
+
+  // parse PEM or DER EC key
+  if (opts->key.buf == NULL) {
+    mg_error(c, "certificate provided without a private key");
+    return;
+  }
+
+  if (mg_parse_pem(opts->key, mg_str_s("EC PRIVATE KEY"), &key) == 0) {
+    if (key.len < 39) {
+      MG_ERROR(("EC private key too short"));
+      return;
+    }
+    // expect ASN.1 SEQUENCE=[INTEGER=1, BITSTRING of 32 bytes, ...]
+    // 30 nn 02 01 01 04 20 [key] ...
+    if (key.buf[0] != 0x30 || (key.buf[1] & 0x80) != 0) {
+      MG_ERROR(("EC private key: ASN.1 bad sequence"));
+      return;
+    }
+    if (memcmp(key.buf + 2, "\x02\x01\x01\x04\x20", 5) != 0) {
+      MG_ERROR(("EC private key: ASN.1 bad data"));
+    }
+    memmove(tls->server_key, key.buf + 7, 32);
+    free((void *) key.buf);
+  } else if (mg_parse_pem(opts->key, mg_str_s("PRIVATE KEY"), &key) == 0) {
+    mg_error(c, "PKCS8 private key format is not supported");
   } else {
-    mg_rpc_err(r, -32601, "\"%.*s not found\"", (int) method.len, method.ptr);
+    mg_error(c, "expected EC PRIVATE KEY or PRIVATE KEY");
   }
 }
 
-void mg_rpc_process(struct mg_rpc_req *r) {
-  int len, off = mg_json_get(r->frame, "$.method", &len);
-  if (off > 0 && r->frame.ptr[off] == '"') {
-    struct mg_str method = mg_str_n(&r->frame.ptr[off + 1], (size_t) len - 2);
-    mg_rpc_call(r, method);
-  } else if ((off = mg_json_get(r->frame, "$.result", &len)) > 0 ||
-             (off = mg_json_get(r->frame, "$.error", &len)) > 0) {
-    mg_rpc_call(r, mg_str(""));  // JSON response! call "" method handler
-  } else {
-    mg_rpc_err(r, -32700, "%.*Q", (int) r->frame.len, r->frame.ptr);  // Invalid
+void mg_tls_free(struct mg_connection *c) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  if (tls != NULL) {
+    mg_iobuf_free(&tls->send);
+    free((void *) tls->server_cert_der.buf);
   }
+  free(c->tls);
+  c->tls = NULL;
 }
 
-void mg_rpc_vok(struct mg_rpc_req *r, const char *fmt, va_list *ap) {
-  int len, off = mg_json_get(r->frame, "$.id", &len);
-  if (off > 0) {
-    mg_xprintf(r->pfn, r->pfn_data, "{%Q:%.*s,%Q:", "id", len,
-               &r->frame.ptr[off], "result");
-    mg_vxprintf(r->pfn, r->pfn_data, fmt == NULL ? "null" : fmt, ap);
-    mg_xprintf(r->pfn, r->pfn_data, "}");
+long mg_tls_send(struct mg_connection *c, const void *buf, size_t len) {
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  long n = MG_IO_WAIT;
+  if (len > MG_IO_SIZE) len = MG_IO_SIZE;
+  mg_tls_encrypt(c, (const uint8_t *) buf, len, MG_TLS_APP_DATA);
+  while (tls->send.len > 0 &&
+         (n = mg_io_send(c, tls->send.buf, tls->send.len)) > 0) {
+    mg_iobuf_del(&tls->send, 0, (size_t) n);
   }
+  if (n == MG_IO_ERR || n == MG_IO_WAIT) return n;
+  return (long) len;
 }
 
-void mg_rpc_ok(struct mg_rpc_req *r, const char *fmt, ...) {
-  va_list ap;
-  va_start(ap, fmt);
-  mg_rpc_vok(r, fmt, &ap);
-  va_end(ap);
-}
+long mg_tls_recv(struct mg_connection *c, void *buf, size_t len) {
+  int r = 0;
+  struct tls_data *tls = (struct tls_data *) c->tls;
+  size_t minlen;
 
-void mg_rpc_verr(struct mg_rpc_req *r, int code, const char *fmt, va_list *ap) {
-  int len, off = mg_json_get(r->frame, "$.id", &len);
-  mg_xprintf(r->pfn, r->pfn_data, "{");
-  if (off > 0) {
-    mg_xprintf(r->pfn, r->pfn_data, "%Q:%.*s,", "id", len, &r->frame.ptr[off]);
+  r = mg_tls_recv_record(c);
+  if (r < 0) {
+    return r;
   }
-  mg_xprintf(r->pfn, r->pfn_data, "%Q:{%Q:%d,%Q:", "error", "code", code,
-             "message");
-  mg_vxprintf(r->pfn, r->pfn_data, fmt == NULL ? "null" : fmt, ap);
-  mg_xprintf(r->pfn, r->pfn_data, "}}");
+  if (tls->content_type != MG_TLS_APP_DATA) {
+    tls->recv.len = 0;
+    mg_tls_drop_record(c);
+    return MG_IO_WAIT;
+  }
+  minlen = len < tls->recv.len ? len : tls->recv.len;
+  memmove(buf, tls->recv.buf, minlen);
+  tls->recv.buf += minlen;
+  tls->recv.len -= minlen;
+  if (tls->recv.len == 0) {
+    mg_tls_drop_record(c);
+  }
+  return (long) minlen;
 }
 
-void mg_rpc_err(struct mg_rpc_req *r, int code, const char *fmt, ...) {
-  va_list ap;
-  va_start(ap, fmt);
-  mg_rpc_verr(r, code, fmt, &ap);
-  va_end(ap);
+size_t mg_tls_pending(struct mg_connection *c) {
+  return mg_tls_got_record(c) ? 1 : 0;
 }
 
-static size_t print_methods(mg_pfn_t pfn, void *pfn_data, va_list *ap) {
-  struct mg_rpc *h, **head = (struct mg_rpc **) va_arg(*ap, void **);
-  size_t len = 0;
-  for (h = *head; h != NULL; h = h->next) {
-    if (h->method.len == 0) continue;  // Ignore response handler
-    len += mg_xprintf(pfn, pfn_data, "%s%.*Q", h == *head ? "" : ",",
-                      (int) h->method.len, h->method.ptr);
-  }
-  return len;
+void mg_tls_ctx_init(struct mg_mgr *mgr) {
+  (void) mgr;
 }
 
-void mg_rpc_list(struct mg_rpc_req *r) {
-  mg_rpc_ok(r, "[%M]", print_methods, r->head);
+void mg_tls_ctx_free(struct mg_mgr *mgr) {
+  (void) mgr;
 }
+#endif
 
 #ifdef MG_ENABLE_LINES
-#line 1 "src/sha1.c"
+#line 1 "src/tls_dummy.c"
+#endif
+
+
+#if MG_TLS == MG_TLS_NONE
+void mg_tls_init(struct mg_connection *c, const struct mg_tls_opts *opts) {
+  (void) opts;
+  mg_error(c, "TLS is not enabled");
+}
+void mg_tls_handshake(struct mg_connection *c) {
+  (void) c;
+}
+void mg_tls_free(struct mg_connection *c) {
+  (void) c;
+}
+long mg_tls_recv(struct mg_connection *c, void *buf, size_t len) {
+  return c == NULL || buf == NULL || len == 0 ? 0 : -1;
+}
+long mg_tls_send(struct mg_connection *c, const void *buf, size_t len) {
+  return c == NULL || buf == NULL || len == 0 ? 0 : -1;
+}
+size_t mg_tls_pending(struct mg_connection *c) {
+  (void) c;
+  return 0;
+}
+void mg_tls_ctx_init(struct mg_mgr *mgr) {
+  (void) mgr;
+}
+void mg_tls_ctx_free(struct mg_mgr *mgr) {
+  (void) mgr;
+}
 #endif
-/* Copyright(c) By Steve Reid <steve@edmweb.com> */
-/* 100% Public Domain */
 
+#ifdef MG_ENABLE_LINES
+#line 1 "src/tls_mbed.c"
+#endif
 
 
-union char64long16 {
-  unsigned char c[64];
-  uint32_t l[16];
-};
 
-#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))
+#if MG_TLS == MG_TLS_MBED
 
-static uint32_t blk0(union char64long16 *block, int i) {
-  if (MG_BIG_ENDIAN) {
-  } else {
-    block->l[i] = (rol(block->l[i], 24) & 0xFF00FF00) |
-                  (rol(block->l[i], 8) & 0x00FF00FF);
+#if defined(MBEDTLS_VERSION_NUMBER) && MBEDTLS_VERSION_NUMBER >= 0x03000000
+#define MG_MBEDTLS_RNG_GET , mg_mbed_rng, NULL
+#else
+#define MG_MBEDTLS_RNG_GET
+#endif
+
+static int mg_mbed_rng(void *ctx, unsigned char *buf, size_t len) {
+  mg_random(buf, len);
+  (void) ctx;
+  return 0;
+}
+
+static bool mg_load_cert(struct mg_str str, mbedtls_x509_crt *p) {
+  int rc;
+  if (str.buf == NULL || str.buf[0] == '\0' || str.buf[0] == '*') return true;
+  if (str.buf[0] == '-') str.len++;  // PEM, include trailing NUL
+  if ((rc = mbedtls_x509_crt_parse(p, (uint8_t *) str.buf, str.len)) != 0) {
+    MG_ERROR(("cert err %#x", -rc));
+    return false;
   }
-  return block->l[i];
+  return true;
 }
 
-/* Avoid redefine warning (ARM /usr/include/sys/ucontext.h define R0~R4) */
-#undef blk
-#undef R0
-#undef R1
-#undef R2
-#undef R3
-#undef R4
+static bool mg_load_key(struct mg_str str, mbedtls_pk_context *p) {
+  int rc;
+  if (str.buf == NULL || str.buf[0] == '\0' || str.buf[0] == '*') return true;
+  if (str.buf[0] == '-') str.len++;  // PEM, include trailing NUL
+  if ((rc = mbedtls_pk_parse_key(p, (uint8_t *) str.buf, str.len, NULL,
+                                 0 MG_MBEDTLS_RNG_GET)) != 0) {
+    MG_ERROR(("key err %#x", -rc));
+    return false;
+  }
+  return true;
+}
 
-#define blk(i)                                                               \
-  (block->l[i & 15] = rol(block->l[(i + 13) & 15] ^ block->l[(i + 8) & 15] ^ \
-                              block->l[(i + 2) & 15] ^ block->l[i & 15],     \
-                          1))
-#define R0(v, w, x, y, z, i)                                          \
-  z += ((w & (x ^ y)) ^ y) + blk0(block, i) + 0x5A827999 + rol(v, 5); \
-  w = rol(w, 30);
-#define R1(v, w, x, y, z, i)                                  \
-  z += ((w & (x ^ y)) ^ y) + blk(i) + 0x5A827999 + rol(v, 5); \
-  w = rol(w, 30);
-#define R2(v, w, x, y, z, i)                          \
-  z += (w ^ x ^ y) + blk(i) + 0x6ED9EBA1 + rol(v, 5); \
-  w = rol(w, 30);
-#define R3(v, w, x, y, z, i)                                        \
-  z += (((w | x) & y) | (w & x)) + blk(i) + 0x8F1BBCDC + rol(v, 5); \
-  w = rol(w, 30);
-#define R4(v, w, x, y, z, i)                          \
-  z += (w ^ x ^ y) + blk(i) + 0xCA62C1D6 + rol(v, 5); \
-  w = rol(w, 30);
+void mg_tls_free(struct mg_connection *c) {
+  struct mg_tls *tls = (struct mg_tls *) c->tls;
+  if (tls != NULL) {
+    mbedtls_ssl_free(&tls->ssl);
+    mbedtls_pk_free(&tls->pk);
+    mbedtls_x509_crt_free(&tls->ca);
+    mbedtls_x509_crt_free(&tls->cert);
+    mbedtls_ssl_config_free(&tls->conf);
+#ifdef MBEDTLS_SSL_SESSION_TICKETS
+    mbedtls_ssl_ticket_free(&tls->ticket);
+#endif
+    free(tls);
+    c->tls = NULL;
+  }
+}
 
-static void mg_sha1_transform(uint32_t state[5],
-                              const unsigned char buffer[64]) {
-  uint32_t a, b, c, d, e;
-  union char64long16 block[1];
+static int mg_net_send(void *ctx, const unsigned char *buf, size_t len) {
+  long n = mg_io_send((struct mg_connection *) ctx, buf, len);
+  MG_VERBOSE(("%lu n=%ld e=%d", ((struct mg_connection *) ctx)->id, n, errno));
+  if (n == MG_IO_WAIT) return MBEDTLS_ERR_SSL_WANT_WRITE;
+  if (n == MG_IO_RESET) return MBEDTLS_ERR_NET_CONN_RESET;
+  if (n == MG_IO_ERR) return MBEDTLS_ERR_NET_SEND_FAILED;
+  return (int) n;
+}
 
-  memcpy(block, buffer, 64);
-  a = state[0];
-  b = state[1];
-  c = state[2];
-  d = state[3];
-  e = state[4];
-  R0(a, b, c, d, e, 0);
-  R0(e, a, b, c, d, 1);
-  R0(d, e, a, b, c, 2);
-  R0(c, d, e, a, b, 3);
-  R0(b, c, d, e, a, 4);
-  R0(a, b, c, d, e, 5);
-  R0(e, a, b, c, d, 6);
-  R0(d, e, a, b, c, 7);
-  R0(c, d, e, a, b, 8);
-  R0(b, c, d, e, a, 9);
-  R0(a, b, c, d, e, 10);
-  R0(e, a, b, c, d, 11);
-  R0(d, e, a, b, c, 12);
-  R0(c, d, e, a, b, 13);
-  R0(b, c, d, e, a, 14);
-  R0(a, b, c, d, e, 15);
-  R1(e, a, b, c, d, 16);
-  R1(d, e, a, b, c, 17);
-  R1(c, d, e, a, b, 18);
-  R1(b, c, d, e, a, 19);
-  R2(a, b, c, d, e, 20);
-  R2(e, a, b, c, d, 21);
-  R2(d, e, a, b, c, 22);
-  R2(c, d, e, a, b, 23);
-  R2(b, c, d, e, a, 24);
-  R2(a, b, c, d, e, 25);
-  R2(e, a, b, c, d, 26);
-  R2(d, e, a, b, c, 27);
-  R2(c, d, e, a, b, 28);
-  R2(b, c, d, e, a, 29);
-  R2(a, b, c, d, e, 30);
-  R2(e, a, b, c, d, 31);
-  R2(d, e, a, b, c, 32);
-  R2(c, d, e, a, b, 33);
-  R2(b, c, d, e, a, 34);
-  R2(a, b, c, d, e, 35);
-  R2(e, a, b, c, d, 36);
-  R2(d, e, a, b, c, 37);
-  R2(c, d, e, a, b, 38);
-  R2(b, c, d, e, a, 39);
-  R3(a, b, c, d, e, 40);
-  R3(e, a, b, c, d, 41);
-  R3(d, e, a, b, c, 42);
-  R3(c, d, e, a, b, 43);
-  R3(b, c, d, e, a, 44);
-  R3(a, b, c, d, e, 45);
-  R3(e, a, b, c, d, 46);
-  R3(d, e, a, b, c, 47);
-  R3(c, d, e, a, b, 48);
-  R3(b, c, d, e, a, 49);
-  R3(a, b, c, d, e, 50);
-  R3(e, a, b, c, d, 51);
-  R3(d, e, a, b, c, 52);
-  R3(c, d, e, a, b, 53);
-  R3(b, c, d, e, a, 54);
-  R3(a, b, c, d, e, 55);
-  R3(e, a, b, c, d, 56);
-  R3(d, e, a, b, c, 57);
-  R3(c, d, e, a, b, 58);
-  R3(b, c, d, e, a, 59);
-  R4(a, b, c, d, e, 60);
-  R4(e, a, b, c, d, 61);
-  R4(d, e, a, b, c, 62);
-  R4(c, d, e, a, b, 63);
-  R4(b, c, d, e, a, 64);
-  R4(a, b, c, d, e, 65);
-  R4(e, a, b, c, d, 66);
-  R4(d, e, a, b, c, 67);
-  R4(c, d, e, a, b, 68);
-  R4(b, c, d, e, a, 69);
-  R4(a, b, c, d, e, 70);
-  R4(e, a, b, c, d, 71);
-  R4(d, e, a, b, c, 72);
-  R4(c, d, e, a, b, 73);
-  R4(b, c, d, e, a, 74);
-  R4(a, b, c, d, e, 75);
-  R4(e, a, b, c, d, 76);
-  R4(d, e, a, b, c, 77);
-  R4(c, d, e, a, b, 78);
-  R4(b, c, d, e, a, 79);
-  state[0] += a;
-  state[1] += b;
-  state[2] += c;
-  state[3] += d;
-  state[4] += e;
-  /* Erase working structures. The order of operations is important,
-   * used to ensure that compiler doesn't optimize those out. */
-  memset(block, 0, sizeof(block));
-  a = b = c = d = e = 0;
-  (void) a;
-  (void) b;
-  (void) c;
-  (void) d;
-  (void) e;
+static int mg_net_recv(void *ctx, unsigned char *buf, size_t len) {
+  long n = mg_io_recv((struct mg_connection *) ctx, buf, len);
+  MG_VERBOSE(("%lu n=%ld", ((struct mg_connection *) ctx)->id, n));
+  if (n == MG_IO_WAIT) return MBEDTLS_ERR_SSL_WANT_WRITE;
+  if (n == MG_IO_RESET) return MBEDTLS_ERR_NET_CONN_RESET;
+  if (n == MG_IO_ERR) return MBEDTLS_ERR_NET_RECV_FAILED;
+  return (int) n;
+}
+
+void mg_tls_handshake(struct mg_connection *c) {
+  struct mg_tls *tls = (struct mg_tls *) c->tls;
+  int rc = mbedtls_ssl_handshake(&tls->ssl);
+  if (rc == 0) {  // Success
+    MG_DEBUG(("%lu success", c->id));
+    c->is_tls_hs = 0;
+    mg_call(c, MG_EV_TLS_HS, NULL);
+  } else if (rc == MBEDTLS_ERR_SSL_WANT_READ ||
+             rc == MBEDTLS_ERR_SSL_WANT_WRITE) {  // Still pending
+    MG_VERBOSE(("%lu pending, %d%d %d (-%#x)", c->id, c->is_connecting,
+                c->is_tls_hs, rc, -rc));
+  } else {
+    mg_error(c, "TLS handshake: -%#x", -rc);  // Error
+  }
 }
 
-void mg_sha1_init(mg_sha1_ctx *context) {
-  context->state[0] = 0x67452301;
-  context->state[1] = 0xEFCDAB89;
-  context->state[2] = 0x98BADCFE;
-  context->state[3] = 0x10325476;
-  context->state[4] = 0xC3D2E1F0;
-  context->count[0] = context->count[1] = 0;
+static void debug_cb(void *c, int lev, const char *s, int n, const char *s2) {
+  n = (int) strlen(s2) - 1;
+  MG_INFO(("%lu %d %.*s", ((struct mg_connection *) c)->id, lev, n, s2));
+  (void) s;
 }
 
-void mg_sha1_update(mg_sha1_ctx *context, const unsigned char *data,
-                    size_t len) {
-  size_t i, j;
+void mg_tls_init(struct mg_connection *c, const struct mg_tls_opts *opts) {
+  struct mg_tls *tls = (struct mg_tls *) calloc(1, sizeof(*tls));
+  int rc = 0;
+  c->tls = tls;
+  if (c->tls == NULL) {
+    mg_error(c, "TLS OOM");
+    goto fail;
+  }
+  if (c->is_listening) goto fail;
+  MG_DEBUG(("%lu Setting TLS", c->id));
+  MG_PROF_ADD(c, "mbedtls_init_start");
+#if defined(MBEDTLS_VERSION_NUMBER) && MBEDTLS_VERSION_NUMBER >= 0x03000000 && \
+    defined(MBEDTLS_PSA_CRYPTO_C)
+  psa_crypto_init();  // https://github.com/Mbed-TLS/mbedtls/issues/9072#issuecomment-2084845711
+#endif
+  mbedtls_ssl_init(&tls->ssl);
+  mbedtls_ssl_config_init(&tls->conf);
+  mbedtls_x509_crt_init(&tls->ca);
+  mbedtls_x509_crt_init(&tls->cert);
+  mbedtls_pk_init(&tls->pk);
+  mbedtls_ssl_conf_dbg(&tls->conf, debug_cb, c);
+#if defined(MG_MBEDTLS_DEBUG_LEVEL)
+  mbedtls_debug_set_threshold(MG_MBEDTLS_DEBUG_LEVEL);
+#endif
+  if ((rc = mbedtls_ssl_config_defaults(
+           &tls->conf,
+           c->is_client ? MBEDTLS_SSL_IS_CLIENT : MBEDTLS_SSL_IS_SERVER,
+           MBEDTLS_SSL_TRANSPORT_STREAM, MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
+    mg_error(c, "tls defaults %#x", -rc);
+    goto fail;
+  }
+  mbedtls_ssl_conf_rng(&tls->conf, mg_mbed_rng, c);
 
-  j = context->count[0];
-  if ((context->count[0] += (uint32_t) len << 3) < j) context->count[1]++;
-  context->count[1] += (uint32_t) (len >> 29);
-  j = (j >> 3) & 63;
-  if ((j + len) > 63) {
-    memcpy(&context->buffer[j], data, (i = 64 - j));
-    mg_sha1_transform(context->state, context->buffer);
-    for (; i + 63 < len; i += 64) {
-      mg_sha1_transform(context->state, &data[i]);
+  if (opts->ca.len == 0 || mg_strcmp(opts->ca, mg_str("*")) == 0) {
+    // NOTE: MBEDTLS_SSL_VERIFY_NONE is not supported for TLS1.3 on client side
+    // See https://github.com/Mbed-TLS/mbedtls/issues/7075
+    mbedtls_ssl_conf_authmode(&tls->conf, MBEDTLS_SSL_VERIFY_NONE);
+  } else {
+    if (mg_load_cert(opts->ca, &tls->ca) == false) goto fail;
+    mbedtls_ssl_conf_ca_chain(&tls->conf, &tls->ca, NULL);
+    if (c->is_client && opts->name.buf != NULL && opts->name.buf[0] != '\0') {
+      char *host = mg_mprintf("%.*s", opts->name.len, opts->name.buf);
+      mbedtls_ssl_set_hostname(&tls->ssl, host);
+      MG_DEBUG(("%lu hostname verification: %s", c->id, host));
+      free(host);
     }
-    j = 0;
-  } else
-    i = 0;
-  memcpy(&context->buffer[j], &data[i], len - i);
+    mbedtls_ssl_conf_authmode(&tls->conf, MBEDTLS_SSL_VERIFY_REQUIRED);
+  }
+  if (!mg_load_cert(opts->cert, &tls->cert)) goto fail;
+  if (!mg_load_key(opts->key, &tls->pk)) goto fail;
+  if (tls->cert.version &&
+      (rc = mbedtls_ssl_conf_own_cert(&tls->conf, &tls->cert, &tls->pk)) != 0) {
+    mg_error(c, "own cert %#x", -rc);
+    goto fail;
+  }
+
+#ifdef MBEDTLS_SSL_SESSION_TICKETS
+  mbedtls_ssl_conf_session_tickets_cb(
+      &tls->conf, mbedtls_ssl_ticket_write, mbedtls_ssl_ticket_parse,
+      &((struct mg_tls_ctx *) c->mgr->tls_ctx)->tickets);
+#endif
+
+  if ((rc = mbedtls_ssl_setup(&tls->ssl, &tls->conf)) != 0) {
+    mg_error(c, "setup err %#x", -rc);
+    goto fail;
+  }
+  c->is_tls = 1;
+  c->is_tls_hs = 1;
+  mbedtls_ssl_set_bio(&tls->ssl, c, mg_net_send, mg_net_recv, 0);
+  MG_PROF_ADD(c, "mbedtls_init_end");
+  if (c->is_client && c->is_resolving == 0 && c->is_connecting == 0) {
+    mg_tls_handshake(c);
+  }
+  return;
+fail:
+  mg_tls_free(c);
 }
 
-void mg_sha1_final(unsigned char digest[20], mg_sha1_ctx *context) {
-  unsigned i;
-  unsigned char finalcount[8], c;
+size_t mg_tls_pending(struct mg_connection *c) {
+  struct mg_tls *tls = (struct mg_tls *) c->tls;
+  return tls == NULL ? 0 : mbedtls_ssl_get_bytes_avail(&tls->ssl);
+}
 
-  for (i = 0; i < 8; i++) {
-    finalcount[i] = (unsigned char) ((context->count[(i >= 4 ? 0 : 1)] >>
-                                      ((3 - (i & 3)) * 8)) &
-                                     255);
+long mg_tls_recv(struct mg_connection *c, void *buf, size_t len) {
+  struct mg_tls *tls = (struct mg_tls *) c->tls;
+  long n = mbedtls_ssl_read(&tls->ssl, (unsigned char *) buf, len);
+  if (n == MBEDTLS_ERR_SSL_WANT_READ || n == MBEDTLS_ERR_SSL_WANT_WRITE)
+    return MG_IO_WAIT;
+#if defined(MBEDTLS_ERR_SSL_RECEIVED_NEW_SESSION_TICKET)
+  if (n == MBEDTLS_ERR_SSL_RECEIVED_NEW_SESSION_TICKET) {
+    return MG_IO_WAIT;
   }
-  c = 0200;
-  mg_sha1_update(context, &c, 1);
-  while ((context->count[0] & 504) != 448) {
-    c = 0000;
-    mg_sha1_update(context, &c, 1);
+#endif
+  if (n <= 0) return MG_IO_ERR;
+  return n;
+}
+
+long mg_tls_send(struct mg_connection *c, const void *buf, size_t len) {
+  struct mg_tls *tls = (struct mg_tls *) c->tls;
+  long n = mbedtls_ssl_write(&tls->ssl, (unsigned char *) buf, len);
+  if (n == MBEDTLS_ERR_SSL_WANT_READ || n == MBEDTLS_ERR_SSL_WANT_WRITE)
+    return MG_IO_WAIT;
+  if (n <= 0) return MG_IO_ERR;
+  return n;
+}
+
+void mg_tls_ctx_init(struct mg_mgr *mgr) {
+  struct mg_tls_ctx *ctx = (struct mg_tls_ctx *) calloc(1, sizeof(*ctx));
+  if (ctx == NULL) {
+    MG_ERROR(("TLS context init OOM"));
+  } else {
+#ifdef MBEDTLS_SSL_SESSION_TICKETS
+    int rc;
+    mbedtls_ssl_ticket_init(&ctx->tickets);
+    if ((rc = mbedtls_ssl_ticket_setup(&ctx->tickets, mg_mbed_rng, NULL,
+                                       MBEDTLS_CIPHER_AES_128_GCM, 86400)) !=
+        0) {
+      MG_ERROR((" mbedtls_ssl_ticket_setup %#x", -rc));
+    }
+#endif
+    mgr->tls_ctx = ctx;
   }
-  mg_sha1_update(context, finalcount, 8);
-  for (i = 0; i < 20; i++) {
-    digest[i] =
-        (unsigned char) ((context->state[i >> 2] >> ((3 - (i & 3)) * 8)) & 255);
+}
+
+void mg_tls_ctx_free(struct mg_mgr *mgr) {
+  struct mg_tls_ctx *ctx = (struct mg_tls_ctx *) mgr->tls_ctx;
+  if (ctx != NULL) {
+#ifdef MBEDTLS_SSL_SESSION_TICKETS
+    mbedtls_ssl_ticket_free(&ctx->tickets);
+#endif
+    free(ctx);
+    mgr->tls_ctx = NULL;
   }
-  memset(context, '\0', sizeof(*context));
-  memset(&finalcount, '\0', sizeof(finalcount));
 }
+#endif
 
 #ifdef MG_ENABLE_LINES
-#line 1 "src/sntp.c"
+#line 1 "src/tls_openssl.c"
 #endif
 
 
 
+#if MG_TLS == MG_TLS_OPENSSL || MG_TLS == MG_TLS_WOLFSSL
 
+static int tls_err_cb(const char *s, size_t len, void *c) {
+  int n = (int) len - 1;
+  MG_ERROR(("%lu %.*s", ((struct mg_connection *) c)->id, n, s));
+  return 0;  // undocumented
+}
 
+static int mg_tls_err(struct mg_connection *c, struct mg_tls *tls, int res) {
+  int err = SSL_get_error(tls->ssl, res);
+  // We've just fetched the last error from the queue.
+  // Now we need to clear the error queue. If we do not, then the following
+  // can happen (actually reported):
+  //  - A new connection is accept()-ed with cert error (e.g. self-signed cert)
+  //  - Since all accept()-ed connections share listener's context,
+  //  - *ALL* SSL accepted connection report read error on the next poll cycle.
+  //    Thus a single errored connection can close all the rest, unrelated ones.
+  // Clearing the error keeps the shared SSL_CTX in an OK state.
 
-#define SNTP_TIME_OFFSET 2208988800U  // (1970 - 1900) in seconds
-#define SNTP_MAX_FRAC 4294967295.0    // 2 ** 32 - 1
+  if (err != 0) ERR_print_errors_cb(tls_err_cb, c);
+  ERR_clear_error();
+  if (err == SSL_ERROR_WANT_READ) return 0;
+  if (err == SSL_ERROR_WANT_WRITE) return 0;
+  return err;
+}
 
-static int64_t gettimestamp(const uint32_t *data) {
-  uint32_t sec = mg_ntohl(data[0]), frac = mg_ntohl(data[1]);
-  if (sec) sec -= SNTP_TIME_OFFSET;
-  return ((int64_t) sec) * 1000 + (int64_t) (frac / SNTP_MAX_FRAC * 1000.0);
+static STACK_OF(X509_INFO) * load_ca_certs(struct mg_str ca) {
+  BIO *bio = BIO_new_mem_buf(ca.buf, (int) ca.len);
+  STACK_OF(X509_INFO) *certs =
+      bio ? PEM_X509_INFO_read_bio(bio, NULL, NULL, NULL) : NULL;
+  if (bio) BIO_free(bio);
+  return certs;
 }
 
-int64_t mg_sntp_parse(const unsigned char *buf, size_t len) {
-  int64_t res = -1;
-  int mode = len > 0 ? buf[0] & 7 : 0;
-  int version = len > 0 ? (buf[0] >> 3) & 7 : 0;
-  if (len < 48) {
-    MG_ERROR(("%s", "corrupt packet"));
-  } else if (mode != 4 && mode != 5) {
-    MG_ERROR(("%s", "not a server reply"));
-  } else if (buf[1] == 0) {
-    MG_ERROR(("%s", "server sent a kiss of death"));
-  } else if (version == 4 || version == 3) {
-    // int64_t ref = gettimestamp((uint32_t *) &buf[16]);
-    int64_t t0 = gettimestamp((uint32_t *) &buf[24]);
-    int64_t t1 = gettimestamp((uint32_t *) &buf[32]);
-    int64_t t2 = gettimestamp((uint32_t *) &buf[40]);
-    int64_t t3 = (int64_t) mg_millis();
-    int64_t delta = (t3 - t0) - (t2 - t1);
-    MG_VERBOSE(("%lld %lld %lld %lld delta:%lld", t0, t1, t2, t3, delta));
-    res = t2 + delta / 2;
-  } else {
-    MG_ERROR(("unexpected version: %d", version));
+static bool add_ca_certs(SSL_CTX *ctx, STACK_OF(X509_INFO) * certs) {
+  X509_STORE *cert_store = SSL_CTX_get_cert_store(ctx);
+  for (int i = 0; i < sk_X509_INFO_num(certs); i++) {
+    X509_INFO *cert_info = sk_X509_INFO_value(certs, i);
+    if (cert_info->x509 && !X509_STORE_add_cert(cert_store, cert_info->x509))
+      return false;
+  }
+  return true;
+}
+
+static EVP_PKEY *load_key(struct mg_str s) {
+  BIO *bio = BIO_new_mem_buf(s.buf, (int) (long) s.len);
+  EVP_PKEY *key = bio ? PEM_read_bio_PrivateKey(bio, NULL, 0, NULL) : NULL;
+  if (bio) BIO_free(bio);
+  return key;
+}
+
+static X509 *load_cert(struct mg_str s) {
+  BIO *bio = BIO_new_mem_buf(s.buf, (int) (long) s.len);
+  X509 *cert = bio == NULL ? NULL
+               : s.buf[0] == '-'
+                   ? PEM_read_bio_X509(bio, NULL, NULL, NULL)  // PEM
+                   : d2i_X509_bio(bio, NULL);                  // DER
+  if (bio) BIO_free(bio);
+  return cert;
+}
+
+static long mg_bio_ctrl(BIO *b, int cmd, long larg, void *pargs) {
+  long ret = 0;
+  if (cmd == BIO_CTRL_PUSH) ret = 1;
+  if (cmd == BIO_CTRL_POP) ret = 1;
+  if (cmd == BIO_CTRL_FLUSH) ret = 1;
+#if MG_TLS == MG_TLS_OPENSSL
+  if (cmd == BIO_C_SET_NBIO) ret = 1;
+#endif
+  // MG_DEBUG(("%d -> %ld", cmd, ret));
+  (void) b, (void) cmd, (void) larg, (void) pargs;
+  return ret;
+}
+
+static int mg_bio_read(BIO *bio, char *buf, int len) {
+  struct mg_connection *c = (struct mg_connection *) BIO_get_data(bio);
+  long res = mg_io_recv(c, buf, (size_t) len);
+  // MG_DEBUG(("%p %d %ld", buf, len, res));
+  len = res > 0 ? (int) res : -1;
+  if (res == MG_IO_WAIT) BIO_set_retry_read(bio);
+  return len;
+}
+
+static int mg_bio_write(BIO *bio, const char *buf, int len) {
+  struct mg_connection *c = (struct mg_connection *) BIO_get_data(bio);
+  long res = mg_io_send(c, buf, (size_t) len);
+  // MG_DEBUG(("%p %d %ld", buf, len, res));
+  len = res > 0 ? (int) res : -1;
+  if (res == MG_IO_WAIT) BIO_set_retry_write(bio);
+  return len;
+}
+
+void mg_tls_init(struct mg_connection *c, const struct mg_tls_opts *opts) {
+  struct mg_tls *tls = (struct mg_tls *) calloc(1, sizeof(*tls));
+  const char *id = "mongoose";
+  static unsigned char s_initialised = 0;
+  BIO *bio = NULL;
+  int rc;
+
+  if (tls == NULL) {
+    mg_error(c, "TLS OOM");
+    goto fail;
+  }
+
+  if (!s_initialised) {
+    SSL_library_init();
+    s_initialised++;
+  }
+  MG_DEBUG(("%lu Setting TLS", c->id));
+  tls->ctx = c->is_client ? SSL_CTX_new(SSLv23_client_method())
+                          : SSL_CTX_new(SSLv23_server_method());
+  if ((tls->ssl = SSL_new(tls->ctx)) == NULL) {
+    mg_error(c, "SSL_new");
+    goto fail;
+  }
+  SSL_set_session_id_context(tls->ssl, (const uint8_t *) id,
+                             (unsigned) strlen(id));
+  // Disable deprecated protocols
+  SSL_set_options(tls->ssl, SSL_OP_NO_SSLv2);
+  SSL_set_options(tls->ssl, SSL_OP_NO_SSLv3);
+  SSL_set_options(tls->ssl, SSL_OP_NO_TLSv1);
+  SSL_set_options(tls->ssl, SSL_OP_NO_TLSv1_1);
+#ifdef MG_ENABLE_OPENSSL_NO_COMPRESSION
+  SSL_set_options(tls->ssl, SSL_OP_NO_COMPRESSION);
+#endif
+#ifdef MG_ENABLE_OPENSSL_CIPHER_SERVER_PREFERENCE
+  SSL_set_options(tls->ssl, SSL_OP_CIPHER_SERVER_PREFERENCE);
+#endif
+
+#if MG_TLS == MG_TLS_WOLFSSL && !defined(OPENSSL_COMPATIBLE_DEFAULTS)
+  if (opts->ca.len == 0 || mg_strcmp(opts->ca, mg_str("*")) == 0) {
+    // Older versions require that either the CA is loaded or SSL_VERIFY_NONE
+    // explicitly set
+    SSL_set_verify(tls->ssl, SSL_VERIFY_NONE, NULL);
+  }
+#endif
+  if (opts->ca.buf != NULL && opts->ca.buf[0] != '\0') {
+    SSL_set_verify(tls->ssl, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
+                   NULL);
+    STACK_OF(X509_INFO) *certs = load_ca_certs(opts->ca);
+    rc = add_ca_certs(tls->ctx, certs);
+    sk_X509_INFO_pop_free(certs, X509_INFO_free);
+    if (!rc) {
+      mg_error(c, "CA err");
+      goto fail;
+    }
+  }
+  if (opts->cert.buf != NULL && opts->cert.buf[0] != '\0') {
+    X509 *cert = load_cert(opts->cert);
+    rc = cert == NULL ? 0 : SSL_use_certificate(tls->ssl, cert);
+    X509_free(cert);
+    if (cert == NULL || rc != 1) {
+      mg_error(c, "CERT err %d", mg_tls_err(c, tls, rc));
+      goto fail;
+    }
+  }
+  if (opts->key.buf != NULL && opts->key.buf[0] != '\0') {
+    EVP_PKEY *key = load_key(opts->key);
+    rc = key == NULL ? 0 : SSL_use_PrivateKey(tls->ssl, key);
+    EVP_PKEY_free(key);
+    if (key == NULL || rc != 1) {
+      mg_error(c, "KEY err %d", mg_tls_err(c, tls, rc));
+      goto fail;
+    }
+  }
+
+  SSL_set_mode(tls->ssl, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
+#if MG_TLS == MG_TLS_OPENSSL && OPENSSL_VERSION_NUMBER > 0x10002000L
+  (void) SSL_set_ecdh_auto(tls->ssl, 1);
+#endif
+#if OPENSSL_VERSION_NUMBER >= 0x10100000L
+  if (opts->name.len > 0) {
+    char *s = mg_mprintf("%.*s", (int) opts->name.len, opts->name.buf);
+#if MG_TLS != MG_TLS_WOLFSSL || LIBWOLFSSL_VERSION_HEX >= 0x05005002
+    SSL_set1_host(tls->ssl, s);
+#else
+    X509_VERIFY_PARAM_set1_host(SSL_get0_param(tls->ssl), s, 0);
+#endif
+    SSL_set_tlsext_host_name(tls->ssl, s);
+    free(s);
   }
-  return res;
-}
+#endif
+#if MG_TLS == MG_TLS_WOLFSSL
+  tls->bm = BIO_meth_new(0, "bio_mg");
+#else
+  tls->bm = BIO_meth_new(BIO_get_new_index() | BIO_TYPE_SOURCE_SINK, "bio_mg");
+#endif
+  BIO_meth_set_write(tls->bm, mg_bio_write);
+  BIO_meth_set_read(tls->bm, mg_bio_read);
+  BIO_meth_set_ctrl(tls->bm, mg_bio_ctrl);
 
-static void sntp_cb(struct mg_connection *c, int ev, void *evd, void *fnd) {
-  if (ev == MG_EV_READ) {
-    int64_t milliseconds = mg_sntp_parse(c->recv.buf, c->recv.len);
-    if (milliseconds > 0) {
-      MG_INFO(("%lu got time: %lld ms from epoch", c->id, milliseconds));
-      mg_call(c, MG_EV_SNTP_TIME, (uint64_t *) &milliseconds);
-      MG_VERBOSE(("%u.%u", (unsigned) (milliseconds / 1000),
-                  (unsigned) (milliseconds % 1000)));
-    }
-    mg_iobuf_del(&c->recv, 0, c->recv.len);  // Free receive buffer
-  } else if (ev == MG_EV_CONNECT) {
-    mg_sntp_request(c);
-  } else if (ev == MG_EV_CLOSE) {
+  bio = BIO_new(tls->bm);
+  BIO_set_data(bio, c);
+  SSL_set_bio(tls->ssl, bio, bio);
+
+  c->tls = tls;
+  c->is_tls = 1;
+  c->is_tls_hs = 1;
+  if (c->is_client && c->is_resolving == 0 && c->is_connecting == 0) {
+    mg_tls_handshake(c);
   }
-  (void) fnd;
-  (void) evd;
+  MG_DEBUG(("%lu SSL %s OK", c->id, c->is_accepted ? "accept" : "client"));
+  return;
+fail:
+  free(tls);
 }
 
-void mg_sntp_request(struct mg_connection *c) {
-  if (c->is_resolving) {
-    MG_ERROR(("%lu wait until resolved", c->id));
+void mg_tls_handshake(struct mg_connection *c) {
+  struct mg_tls *tls = (struct mg_tls *) c->tls;
+  int rc = c->is_client ? SSL_connect(tls->ssl) : SSL_accept(tls->ssl);
+  if (rc == 1) {
+    MG_DEBUG(("%lu success", c->id));
+    c->is_tls_hs = 0;
+    mg_call(c, MG_EV_TLS_HS, NULL);
   } else {
-    int64_t now = (int64_t) mg_millis();  // Use int64_t, for vc98
-    uint8_t buf[48] = {0};
-    uint32_t *t = (uint32_t *) &buf[40];
-    double frac = ((double) (now % 1000)) / 1000.0 * SNTP_MAX_FRAC;
-    buf[0] = (0 << 6) | (4 << 3) | 3;
-    t[0] = mg_htonl((uint32_t) (now / 1000) + SNTP_TIME_OFFSET);
-    t[1] = mg_htonl((uint32_t) frac);
-    mg_send(c, buf, sizeof(buf));
+    int code = mg_tls_err(c, tls, rc);
+    if (code != 0) mg_error(c, "tls hs: rc %d, err %d", rc, code);
   }
 }
 
-struct mg_connection *mg_sntp_connect(struct mg_mgr *mgr, const char *url,
-                                      mg_event_handler_t fn, void *fnd) {
-  struct mg_connection *c = NULL;
-  if (url == NULL) url = "udp://time.google.com:123";
-  if ((c = mg_connect(mgr, url, fn, fnd)) != NULL) c->pfn = sntp_cb;
-  return c;
+void mg_tls_free(struct mg_connection *c) {
+  struct mg_tls *tls = (struct mg_tls *) c->tls;
+  if (tls == NULL) return;
+  SSL_free(tls->ssl);
+  SSL_CTX_free(tls->ctx);
+  BIO_meth_free(tls->bm);
+  free(tls);
+  c->tls = NULL;
 }
 
-#ifdef MG_ENABLE_LINES
-#line 1 "src/sock.c"
-#endif
-
+size_t mg_tls_pending(struct mg_connection *c) {
+  struct mg_tls *tls = (struct mg_tls *) c->tls;
+  return tls == NULL ? 0 : (size_t) SSL_pending(tls->ssl);
+}
 
+long mg_tls_recv(struct mg_connection *c, void *buf, size_t len) {
+  struct mg_tls *tls = (struct mg_tls *) c->tls;
+  int n = SSL_read(tls->ssl, buf, (int) len);
+  if (n < 0 && mg_tls_err(c, tls, n) == 0) return MG_IO_WAIT;
+  if (n <= 0) return MG_IO_ERR;
+  return n;
+}
 
+long mg_tls_send(struct mg_connection *c, const void *buf, size_t len) {
+  struct mg_tls *tls = (struct mg_tls *) c->tls;
+  int n = SSL_write(tls->ssl, buf, (int) len);
+  if (n < 0 && mg_tls_err(c, tls, n) == 0) return MG_IO_WAIT;
+  if (n <= 0) return MG_IO_ERR;
+  return n;
+}
 
+void mg_tls_ctx_init(struct mg_mgr *mgr) {
+  (void) mgr;
+}
 
+void mg_tls_ctx_free(struct mg_mgr *mgr) {
+  (void) mgr;
+}
+#endif
 
+#ifdef MG_ENABLE_LINES
+#line 1 "src/tls_uecc.c"
+#endif
+/* Copyright 2014, Kenneth MacKay. Licensed under the BSD 2-clause license. */
 
 
 
 
-#if MG_ENABLE_SOCKET
+#if MG_TLS == MG_TLS_BUILTIN
 
-#ifndef closesocket
-#define closesocket(x) close(x)
+#ifndef MG_UECC_RNG_MAX_TRIES
+#define MG_UECC_RNG_MAX_TRIES 64
 #endif
 
-#define FD(c_) ((MG_SOCKET_TYPE) (size_t) (c_)->fd)
-#define S2PTR(s_) ((void *) (size_t) (s_))
-
-#ifndef MSG_NONBLOCKING
-#define MSG_NONBLOCKING 0
+#if MG_UECC_ENABLE_VLI_API
+#define MG_UECC_VLI_API
+#else
+#define MG_UECC_VLI_API static
 #endif
 
-#ifndef AF_INET6
-#define AF_INET6 10
+#if (MG_UECC_PLATFORM == mg_uecc_avr) || (MG_UECC_PLATFORM == mg_uecc_arm) || \
+    (MG_UECC_PLATFORM == mg_uecc_arm_thumb) ||                                \
+    (MG_UECC_PLATFORM == mg_uecc_arm_thumb2)
+#define CONCATX(a, ...) a##__VA_ARGS__
+#define CONCAT(a, ...) CONCATX(a, __VA_ARGS__)
+
+#define STRX(a) #a
+#define STR(a) STRX(a)
+
+#define EVAL(...) EVAL1(EVAL1(EVAL1(EVAL1(__VA_ARGS__))))
+#define EVAL1(...) EVAL2(EVAL2(EVAL2(EVAL2(__VA_ARGS__))))
+#define EVAL2(...) EVAL3(EVAL3(EVAL3(EVAL3(__VA_ARGS__))))
+#define EVAL3(...) EVAL4(EVAL4(EVAL4(EVAL4(__VA_ARGS__))))
+#define EVAL4(...) __VA_ARGS__
+
+#define DEC_1 0
+#define DEC_2 1
+#define DEC_3 2
+#define DEC_4 3
+#define DEC_5 4
+#define DEC_6 5
+#define DEC_7 6
+#define DEC_8 7
+#define DEC_9 8
+#define DEC_10 9
+#define DEC_11 10
+#define DEC_12 11
+#define DEC_13 12
+#define DEC_14 13
+#define DEC_15 14
+#define DEC_16 15
+#define DEC_17 16
+#define DEC_18 17
+#define DEC_19 18
+#define DEC_20 19
+#define DEC_21 20
+#define DEC_22 21
+#define DEC_23 22
+#define DEC_24 23
+#define DEC_25 24
+#define DEC_26 25
+#define DEC_27 26
+#define DEC_28 27
+#define DEC_29 28
+#define DEC_30 29
+#define DEC_31 30
+#define DEC_32 31
+
+#define DEC(N) CONCAT(DEC_, N)
+
+#define SECOND_ARG(_, val, ...) val
+#define SOME_CHECK_0 ~, 0
+#define GET_SECOND_ARG(...) SECOND_ARG(__VA_ARGS__, SOME, )
+#define SOME_OR_0(N) GET_SECOND_ARG(CONCAT(SOME_CHECK_, N))
+
+#define EMPTY(...)
+#define DEFER(...) __VA_ARGS__ EMPTY()
+
+#define REPEAT_NAME_0() REPEAT_0
+#define REPEAT_NAME_SOME() REPEAT_SOME
+#define REPEAT_0(...)
+#define REPEAT_SOME(N, stuff) \
+  DEFER(CONCAT(REPEAT_NAME_, SOME_OR_0(DEC(N))))()(DEC(N), stuff) stuff
+#define REPEAT(N, stuff) EVAL(REPEAT_SOME(N, stuff))
+
+#define REPEATM_NAME_0() REPEATM_0
+#define REPEATM_NAME_SOME() REPEATM_SOME
+#define REPEATM_0(...)
+#define REPEATM_SOME(N, macro) \
+  macro(N) DEFER(CONCAT(REPEATM_NAME_, SOME_OR_0(DEC(N))))()(DEC(N), macro)
+#define REPEATM(N, macro) EVAL(REPEATM_SOME(N, macro))
 #endif
 
-union usa {
-  struct sockaddr sa;
-  struct sockaddr_in sin;
-#if MG_ENABLE_IPV6
-  struct sockaddr_in6 sin6;
-#endif
-};
+// 
 
-static socklen_t tousa(struct mg_addr *a, union usa *usa) {
-  socklen_t len = sizeof(usa->sin);
-  memset(usa, 0, sizeof(*usa));
-  usa->sin.sin_family = AF_INET;
-  usa->sin.sin_port = a->port;
-  *(uint32_t *) &usa->sin.sin_addr = a->ip;
-#if MG_ENABLE_IPV6
-  if (a->is_ip6) {
-    usa->sin.sin_family = AF_INET6;
-    usa->sin6.sin6_port = a->port;
-    memcpy(&usa->sin6.sin6_addr, a->ip6, sizeof(a->ip6));
-    len = sizeof(usa->sin6);
-  }
+#if (MG_UECC_WORD_SIZE == 1)
+#if MG_UECC_SUPPORTS_secp160r1
+#define MG_UECC_MAX_WORDS 21 /* Due to the size of curve_n. */
 #endif
-  return len;
-}
-
-static void tomgaddr(union usa *usa, struct mg_addr *a, bool is_ip6) {
-  a->is_ip6 = is_ip6;
-  a->port = usa->sin.sin_port;
-  memcpy(&a->ip, &usa->sin.sin_addr, sizeof(a->ip));
-#if MG_ENABLE_IPV6
-  if (is_ip6) {
-    memcpy(a->ip6, &usa->sin6.sin6_addr, sizeof(a->ip6));
-    a->port = usa->sin6.sin6_port;
-  }
+#if MG_UECC_SUPPORTS_secp192r1
+#undef MG_UECC_MAX_WORDS
+#define MG_UECC_MAX_WORDS 24
 #endif
-}
-
-static bool mg_sock_would_block(void) {
-  int err = MG_SOCKET_ERRNO;
-  return err == EINPROGRESS || err == EWOULDBLOCK
-#ifndef WINCE
-         || err == EAGAIN || err == EINTR
+#if MG_UECC_SUPPORTS_secp224r1
+#undef MG_UECC_MAX_WORDS
+#define MG_UECC_MAX_WORDS 28
 #endif
-#if MG_ARCH == MG_ARCH_WIN32 && MG_ENABLE_WINSOCK
-         || err == WSAEINTR || err == WSAEWOULDBLOCK
+#if (MG_UECC_SUPPORTS_secp256r1 || MG_UECC_SUPPORTS_secp256k1)
+#undef MG_UECC_MAX_WORDS
+#define MG_UECC_MAX_WORDS 32
 #endif
-      ;
-}
-
-static bool mg_sock_conn_reset(void) {
-  int err = MG_SOCKET_ERRNO;
-#if MG_ARCH == MG_ARCH_WIN32 && MG_ENABLE_WINSOCK
-  return err == WSAECONNRESET;
-#else
-  return err == EPIPE || err == ECONNRESET;
+#elif (MG_UECC_WORD_SIZE == 4)
+#if MG_UECC_SUPPORTS_secp160r1
+#define MG_UECC_MAX_WORDS 6 /* Due to the size of curve_n. */
 #endif
-}
+#if MG_UECC_SUPPORTS_secp192r1
+#undef MG_UECC_MAX_WORDS
+#define MG_UECC_MAX_WORDS 6
+#endif
+#if MG_UECC_SUPPORTS_secp224r1
+#undef MG_UECC_MAX_WORDS
+#define MG_UECC_MAX_WORDS 7
+#endif
+#if (MG_UECC_SUPPORTS_secp256r1 || MG_UECC_SUPPORTS_secp256k1)
+#undef MG_UECC_MAX_WORDS
+#define MG_UECC_MAX_WORDS 8
+#endif
+#elif (MG_UECC_WORD_SIZE == 8)
+#if MG_UECC_SUPPORTS_secp160r1
+#define MG_UECC_MAX_WORDS 3
+#endif
+#if MG_UECC_SUPPORTS_secp192r1
+#undef MG_UECC_MAX_WORDS
+#define MG_UECC_MAX_WORDS 3
+#endif
+#if MG_UECC_SUPPORTS_secp224r1
+#undef MG_UECC_MAX_WORDS
+#define MG_UECC_MAX_WORDS 4
+#endif
+#if (MG_UECC_SUPPORTS_secp256r1 || MG_UECC_SUPPORTS_secp256k1)
+#undef MG_UECC_MAX_WORDS
+#define MG_UECC_MAX_WORDS 4
+#endif
+#endif /* MG_UECC_WORD_SIZE */
+
+#define BITS_TO_WORDS(num_bits)                                \
+  ((wordcount_t) ((num_bits + ((MG_UECC_WORD_SIZE * 8) - 1)) / \
+                  (MG_UECC_WORD_SIZE * 8)))
+#define BITS_TO_BYTES(num_bits) ((num_bits + 7) / 8)
+
+struct MG_UECC_Curve_t {
+  wordcount_t num_words;
+  wordcount_t num_bytes;
+  bitcount_t num_n_bits;
+  mg_uecc_word_t p[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t n[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t G[MG_UECC_MAX_WORDS * 2];
+  mg_uecc_word_t b[MG_UECC_MAX_WORDS];
+  void (*double_jacobian)(mg_uecc_word_t *X1, mg_uecc_word_t *Y1,
+                          mg_uecc_word_t *Z1, MG_UECC_Curve curve);
+#if MG_UECC_SUPPORT_COMPRESSED_POINT
+  void (*mod_sqrt)(mg_uecc_word_t *a, MG_UECC_Curve curve);
+#endif
+  void (*x_side)(mg_uecc_word_t *result, const mg_uecc_word_t *x,
+                 MG_UECC_Curve curve);
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0)
+  void (*mmod_fast)(mg_uecc_word_t *result, mg_uecc_word_t *product);
+#endif
+};
 
-static void setlocaddr(MG_SOCKET_TYPE fd, struct mg_addr *addr) {
-  union usa usa;
-  socklen_t n = sizeof(usa);
-  if (getsockname(fd, &usa.sa, &n) == 0) {
-    tomgaddr(&usa, addr, n != sizeof(usa.sin));
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN
+static void bcopy(uint8_t *dst, const uint8_t *src, unsigned num_bytes) {
+  while (0 != num_bytes) {
+    num_bytes--;
+    dst[num_bytes] = src[num_bytes];
   }
 }
+#endif
 
-static void iolog(struct mg_connection *c, char *buf, long n, bool r) {
-  if (n == MG_IO_WAIT) {
-    // Do nothing
-  } else if (n <= 0) {
-    c->is_closing = 1;  // Termination. Don't call mg_error(): #1529
-  } else if (n > 0) {
-    if (c->is_hexdumping) {
-      union usa usa;
-      socklen_t slen = sizeof(usa.sin);
-      if (getsockname(FD(c), &usa.sa, &slen) < 0) (void) 0;  // Ignore result
-      MG_INFO(("\n-- %lu %I %s %I %ld", c->id, 4, &usa.sin.sin_addr,
-               r ? "<-" : "->", 4, &c->rem.ip, n));
+static cmpresult_t mg_uecc_vli_cmp_unsafe(const mg_uecc_word_t *left,
+                                          const mg_uecc_word_t *right,
+                                          wordcount_t num_words);
 
-      mg_hexdump(buf, (size_t) n);
-    }
-    if (r) {
-      c->recv.len += (size_t) n;
-      mg_call(c, MG_EV_READ, &n);
-    } else {
-      mg_iobuf_del(&c->send, 0, (size_t) n);
-      // if (c->send.len == 0) mg_iobuf_resize(&c->send, 0);
-      if (c->send.len == 0) {
-        MG_EPOLL_MOD(c, 0);
-      }
-      mg_call(c, MG_EV_WRITE, &n);
-    }
-  }
-}
+#if (MG_UECC_PLATFORM == mg_uecc_arm ||       \
+     MG_UECC_PLATFORM == mg_uecc_arm_thumb || \
+     MG_UECC_PLATFORM == mg_uecc_arm_thumb2)
 
-long mg_io_send(struct mg_connection *c, const void *buf, size_t len) {
-  long n;
-  if (c->is_udp) {
-    union usa usa;
-    socklen_t slen = tousa(&c->rem, &usa);
-    n = sendto(FD(c), (char *) buf, len, 0, &usa.sa, slen);
-    if (n > 0) setlocaddr(FD(c), &c->loc);
-  } else {
-    n = send(FD(c), (char *) buf, len, MSG_NONBLOCKING);
-#if MG_ARCH == MG_ARCH_RTX
-    if (n == EWOULDBLOCK) return MG_IO_WAIT;
 #endif
-  }
-  if (n < 0 && mg_sock_would_block()) return MG_IO_WAIT;
-  if (n < 0 && mg_sock_conn_reset()) return MG_IO_RESET;
-  if (n <= 0) return MG_IO_ERR;
-  return n;
-}
 
-bool mg_send(struct mg_connection *c, const void *buf, size_t len) {
-  if (c->is_udp) {
-    long n = mg_io_send(c, buf, len);
-    MG_DEBUG(("%lu %p %d:%d %ld err %d", c->id, c->fd, (int) c->send.len,
-              (int) c->recv.len, n, MG_SOCKET_ERRNO));
-    iolog(c, (char *) buf, n, false);
-    return n > 0;
-  } else {
-    return mg_iobuf_add(&c->send, c->send.len, buf, len);
-  }
-}
+#if (MG_UECC_PLATFORM == mg_uecc_avr)
 
-static void mg_set_non_blocking_mode(MG_SOCKET_TYPE fd) {
-#if defined(MG_CUSTOM_NONBLOCK)
-  MG_CUSTOM_NONBLOCK(fd);
-#elif MG_ARCH == MG_ARCH_WIN32 && MG_ENABLE_WINSOCK
-  unsigned long on = 1;
-  ioctlsocket(fd, FIONBIO, &on);
-#elif MG_ARCH == MG_ARCH_RTX
-  unsigned long on = 1;
-  ioctlsocket(fd, FIONBIO, &on);
-#elif MG_ENABLE_FREERTOS_TCP
-  const BaseType_t off = 0;
-  if (setsockopt(fd, 0, FREERTOS_SO_RCVTIMEO, &off, sizeof(off)) != 0) (void) 0;
-  if (setsockopt(fd, 0, FREERTOS_SO_SNDTIMEO, &off, sizeof(off)) != 0) (void) 0;
-#elif MG_ENABLE_LWIP
-  lwip_fcntl(fd, F_SETFL, O_NONBLOCK);
-#elif MG_ARCH == MG_ARCH_AZURERTOS
-  fcntl(fd, F_SETFL, O_NONBLOCK);
-#elif MG_ARCH == MG_ARCH_TIRTOS
-  int val = 0;
-  setsockopt(fd, SOL_SOCKET, SO_BLOCKING, &val, sizeof(val));
-  // SPRU524J section 3.3.3 page 63, SO_SNDLOWAT
-  int sz = sizeof(val);
-  getsockopt(fd, SOL_SOCKET, SO_SNDBUF, &val, &sz);
-  val /= 2;  // set send low-water mark at half send buffer size
-  setsockopt(fd, SOL_SOCKET, SO_SNDLOWAT, &val, sizeof(val));
-#else
-  fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK);  // Non-blocking mode
-  fcntl(fd, F_SETFD, FD_CLOEXEC);                          // Set close-on-exec
 #endif
-}
 
-bool mg_open_listener(struct mg_connection *c, const char *url) {
-  MG_SOCKET_TYPE fd = MG_INVALID_SOCKET;
-  bool success = false;
-  c->loc.port = mg_htons(mg_url_port(url));
-  if (!mg_aton(mg_url_host(url), &c->loc)) {
-    MG_ERROR(("invalid listening URL: %s", url));
-  } else {
-    union usa usa;
-    socklen_t slen = tousa(&c->loc, &usa);
-    int on = 1, af = c->loc.is_ip6 ? AF_INET6 : AF_INET;
-    int type = strncmp(url, "udp:", 4) == 0 ? SOCK_DGRAM : SOCK_STREAM;
-    int proto = type == SOCK_DGRAM ? IPPROTO_UDP : IPPROTO_TCP;
-    (void) on;
+#ifndef asm_clear
+#define asm_clear 0
+#endif
+#ifndef asm_set
+#define asm_set 0
+#endif
+#ifndef asm_add
+#define asm_add 0
+#endif
+#ifndef asm_sub
+#define asm_sub 0
+#endif
+#ifndef asm_mult
+#define asm_mult 0
+#endif
+#ifndef asm_rshift1
+#define asm_rshift1 0
+#endif
+#ifndef asm_mmod_fast_secp256r1
+#define asm_mmod_fast_secp256r1 0
+#endif
 
-    if ((fd = socket(af, type, proto)) == MG_INVALID_SOCKET) {
-      MG_ERROR(("socket: %d", MG_SOCKET_ERRNO));
-#if ((MG_ARCH == MG_ARCH_WIN32) || (MG_ARCH == MG_ARCH_UNIX) || \
-     (defined(LWIP_SOCKET) && SO_REUSE == 1))
-    } else if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *) &on,
-                          sizeof(on)) != 0) {
-      // 1. SO_RESUSEADDR is not enabled on Windows because the semantics of
-      //    SO_REUSEADDR on UNIX and Windows is different. On Windows,
-      //    SO_REUSEADDR allows to bind a socket to a port without error even
-      //    if the port is already open by another program. This is not the
-      //    behavior SO_REUSEADDR was designed for, and leads to hard-to-track
-      //    failure scenarios. Therefore, SO_REUSEADDR was disabled on Windows
-      //    unless SO_EXCLUSIVEADDRUSE is supported and set on a socket.
-      // 2. In case of LWIP, SO_REUSEADDR should be explicitly enabled, by
-      // defining
-      //    SO_REUSE (in lwipopts.h), otherwise the code below will compile
-      //    but won't work! (setsockopt will return EINVAL)
-      MG_ERROR(("reuseaddr: %d", MG_SOCKET_ERRNO));
-#endif
-#if MG_ARCH == MG_ARCH_WIN32 && !defined(SO_EXCLUSIVEADDRUSE) && !defined(WINCE)
-    } else if (setsockopt(fd, SOL_SOCKET, SO_EXCLUSIVEADDRUSE, (char *) &on,
-                          sizeof(on)) != 0) {
-      // "Using SO_REUSEADDR and SO_EXCLUSIVEADDRUSE"
-      MG_ERROR(("exclusiveaddruse: %d", MG_SOCKET_ERRNO));
+#if defined(default_RNG_defined) && default_RNG_defined
+static MG_UECC_RNG_Function g_rng_function = &default_RNG;
+#else
+static MG_UECC_RNG_Function g_rng_function = 0;
 #endif
-    } else if (bind(fd, &usa.sa, slen) != 0) {
-      MG_ERROR(("bind: %d", MG_SOCKET_ERRNO));
-    } else if ((type == SOCK_STREAM &&
-                listen(fd, MG_SOCK_LISTEN_BACKLOG_SIZE) != 0)) {
-      // NOTE(lsm): FreeRTOS uses backlog value as a connection limit
-      // In case port was set to 0, get the real port number
-      MG_ERROR(("listen: %d", MG_SOCKET_ERRNO));
-    } else {
-      setlocaddr(fd, &c->loc);
-      mg_set_non_blocking_mode(fd);
-      c->fd = S2PTR(fd);
-      MG_EPOLL_ADD(c);
-      success = true;
-    }
-  }
-  if (success == false && fd != MG_INVALID_SOCKET) closesocket(fd);
-  return success;
+
+void mg_uecc_set_rng(MG_UECC_RNG_Function rng_function) {
+  g_rng_function = rng_function;
+}
+
+MG_UECC_RNG_Function mg_uecc_get_rng(void) {
+  return g_rng_function;
 }
 
-long mg_io_recv(struct mg_connection *c, void *buf, size_t len) {
-  long n = 0;
-  if (c->is_udp) {
-    union usa usa;
-    socklen_t slen = tousa(&c->rem, &usa);
-    n = recvfrom(FD(c), (char *) buf, len, 0, &usa.sa, &slen);
-    if (n > 0) tomgaddr(&usa, &c->rem, slen != sizeof(usa.sin));
-  } else {
-    n = recv(FD(c), (char *) buf, len, MSG_NONBLOCKING);
+int mg_uecc_curve_private_key_size(MG_UECC_Curve curve) {
+  return BITS_TO_BYTES(curve->num_n_bits);
+}
+
+int mg_uecc_curve_public_key_size(MG_UECC_Curve curve) {
+  return 2 * curve->num_bytes;
+}
+
+#if !asm_clear
+MG_UECC_VLI_API void mg_uecc_vli_clear(mg_uecc_word_t *vli,
+                                       wordcount_t num_words) {
+  wordcount_t i;
+  for (i = 0; i < num_words; ++i) {
+    vli[i] = 0;
   }
-  if (n < 0 && mg_sock_would_block()) return MG_IO_WAIT;
-  if (n < 0 && mg_sock_conn_reset()) return MG_IO_RESET;
-  if (n <= 0) return MG_IO_ERR;
-  return n;
 }
+#endif /* !asm_clear */
 
-// NOTE(lsm): do only one iteration of reads, cause some systems
-// (e.g. FreeRTOS stack) return 0 instead of -1/EWOULDBLOCK when no data
-static void read_conn(struct mg_connection *c) {
-  long n = -1;
-  if (c->recv.len >= MG_MAX_RECV_SIZE) {
-    mg_error(c, "max_recv_buf_size reached");
-  } else if (c->recv.size <= c->recv.len &&
-             !mg_iobuf_resize(&c->recv, c->recv.size + MG_IO_SIZE)) {
-    mg_error(c, "oom");
-  } else {
-    char *buf = (char *) &c->recv.buf[c->recv.len];
-    size_t len = c->recv.size - c->recv.len;
-    n = c->is_tls ? mg_tls_recv(c, buf, len) : mg_io_recv(c, buf, len);
-    MG_DEBUG(("%lu %p snd %ld/%ld rcv %ld/%ld n=%ld err=%d", c->id, c->fd,
-              (long) c->send.len, (long) c->send.size, (long) c->recv.len,
-              (long) c->recv.size, n, MG_SOCKET_ERRNO));
-    iolog(c, buf, n, true);
+/* Constant-time comparison to zero - secure way to compare long integers */
+/* Returns 1 if vli == 0, 0 otherwise. */
+MG_UECC_VLI_API mg_uecc_word_t mg_uecc_vli_isZero(const mg_uecc_word_t *vli,
+                                                  wordcount_t num_words) {
+  mg_uecc_word_t bits = 0;
+  wordcount_t i;
+  for (i = 0; i < num_words; ++i) {
+    bits |= vli[i];
   }
+  return (bits == 0);
 }
 
-static void write_conn(struct mg_connection *c) {
-  char *buf = (char *) c->send.buf;
-  size_t len = c->send.len;
-  long n = c->is_tls ? mg_tls_send(c, buf, len) : mg_io_send(c, buf, len);
-  MG_DEBUG(("%lu %p snd %ld/%ld rcv %ld/%ld n=%ld err=%d", c->id, c->fd,
-            (long) c->send.len, (long) c->send.size, (long) c->recv.len,
-            (long) c->recv.size, n, MG_SOCKET_ERRNO));
-  iolog(c, buf, n, false);
+/* Returns nonzero if bit 'bit' of vli is set. */
+MG_UECC_VLI_API mg_uecc_word_t mg_uecc_vli_testBit(const mg_uecc_word_t *vli,
+                                                   bitcount_t bit) {
+  return (vli[bit >> MG_UECC_WORD_BITS_SHIFT] &
+          ((mg_uecc_word_t) 1 << (bit & MG_UECC_WORD_BITS_MASK)));
 }
 
-static void close_conn(struct mg_connection *c) {
-  if (FD(c) != MG_INVALID_SOCKET) {
-#if MG_ENABLE_EPOLL
-    epoll_ctl(c->mgr->epoll_fd, EPOLL_CTL_DEL, FD(c), NULL);
-#endif
-    closesocket(FD(c));
-#if MG_ENABLE_FREERTOS_TCP
-    FreeRTOS_FD_CLR(c->fd, c->mgr->ss, eSELECT_ALL);
-#endif
+/* Counts the number of words in vli. */
+static wordcount_t vli_numDigits(const mg_uecc_word_t *vli,
+                                 const wordcount_t max_words) {
+  wordcount_t i;
+  /* Search from the end until we find a non-zero digit.
+     We do it in reverse because we expect that most digits will be nonzero. */
+  for (i = max_words - 1; i >= 0 && vli[i] == 0; --i) {
   }
-  mg_close_conn(c);
+
+  return (i + 1);
 }
 
-static void connect_conn(struct mg_connection *c) {
-  union usa usa;
-  socklen_t n = sizeof(usa);
-  // Use getpeername() to test whether we have connected
-  if (getpeername(FD(c), &usa.sa, &n) == 0) {
-    c->is_connecting = 0;
-    mg_call(c, MG_EV_CONNECT, NULL);
-    MG_EPOLL_MOD(c, 0);
-    if (c->is_tls_hs) mg_tls_handshake(c);
-  } else {
-    mg_error(c, "socket error");
+/* Counts the number of bits required to represent vli. */
+MG_UECC_VLI_API bitcount_t mg_uecc_vli_numBits(const mg_uecc_word_t *vli,
+                                               const wordcount_t max_words) {
+  mg_uecc_word_t i;
+  mg_uecc_word_t digit;
+
+  wordcount_t num_digits = vli_numDigits(vli, max_words);
+  if (num_digits == 0) {
+    return 0;
   }
-}
 
-static void setsockopts(struct mg_connection *c) {
-#if MG_ENABLE_FREERTOS_TCP || MG_ARCH == MG_ARCH_AZURERTOS || \
-    MG_ARCH == MG_ARCH_TIRTOS
-  (void) c;
-#else
-  int on = 1;
-#if !defined(SOL_TCP)
-#define SOL_TCP IPPROTO_TCP
-#endif
-  if (setsockopt(FD(c), SOL_TCP, TCP_NODELAY, (char *) &on, sizeof(on)) != 0)
-    (void) 0;
-  if (setsockopt(FD(c), SOL_SOCKET, SO_KEEPALIVE, (char *) &on, sizeof(on)) !=
-      0)
-    (void) 0;
-#endif
+  digit = vli[num_digits - 1];
+  for (i = 0; digit; ++i) {
+    digit >>= 1;
+  }
+
+  return (((bitcount_t) ((num_digits - 1) << MG_UECC_WORD_BITS_SHIFT)) +
+          (bitcount_t) i);
 }
 
-void mg_connect_resolved(struct mg_connection *c) {
-  int type = c->is_udp ? SOCK_DGRAM : SOCK_STREAM;
-  int rc, af = c->rem.is_ip6 ? AF_INET6 : AF_INET;  // c->rem has resolved IP
-  c->fd = S2PTR(socket(af, type, 0));               // Create outbound socket
-  c->is_resolving = 0;                              // Clear resolving flag
-  if (FD(c) == MG_INVALID_SOCKET) {
-    mg_error(c, "socket(): %d", MG_SOCKET_ERRNO);
-  } else if (c->is_udp) {
-    MG_EPOLL_ADD(c);
-#if MG_ARCH == MG_ARCH_TIRTOS
-    union usa usa;  // TI-RTOS NDK requires binding to receive on UDP sockets
-    socklen_t slen = tousa(&c->loc, &usa);
-    if (bind(c->fd, &usa.sa, slen) != 0)
-      MG_ERROR(("bind: %d", MG_SOCKET_ERRNO));
-#endif
-    mg_call(c, MG_EV_RESOLVE, NULL);
-    mg_call(c, MG_EV_CONNECT, NULL);
-  } else {
-    union usa usa;
-    socklen_t slen = tousa(&c->rem, &usa);
-    mg_set_non_blocking_mode(FD(c));
-    setsockopts(c);
-    MG_EPOLL_ADD(c);
-    mg_call(c, MG_EV_RESOLVE, NULL);
-    if ((rc = connect(FD(c), &usa.sa, slen)) == 0) {
-      mg_call(c, MG_EV_CONNECT, NULL);
-    } else if (mg_sock_would_block()) {
-      MG_DEBUG(("%lu %p -> %I:%hu pend", c->id, c->fd, 4, &c->rem.ip,
-                mg_ntohs(c->rem.port)));
-      c->is_connecting = 1;
-    } else {
-      mg_error(c, "connect: %d", MG_SOCKET_ERRNO);
+/* Sets dest = src. */
+#if !asm_set
+MG_UECC_VLI_API void mg_uecc_vli_set(mg_uecc_word_t *dest,
+                                     const mg_uecc_word_t *src,
+                                     wordcount_t num_words) {
+  wordcount_t i;
+  for (i = 0; i < num_words; ++i) {
+    dest[i] = src[i];
+  }
+}
+#endif /* !asm_set */
+
+/* Returns sign of left - right. */
+static cmpresult_t mg_uecc_vli_cmp_unsafe(const mg_uecc_word_t *left,
+                                          const mg_uecc_word_t *right,
+                                          wordcount_t num_words) {
+  wordcount_t i;
+  for (i = num_words - 1; i >= 0; --i) {
+    if (left[i] > right[i]) {
+      return 1;
+    } else if (left[i] < right[i]) {
+      return -1;
     }
   }
-  (void) rc;
+  return 0;
 }
 
-static MG_SOCKET_TYPE raccept(MG_SOCKET_TYPE sock, union usa *usa,
-                              socklen_t *len) {
-  MG_SOCKET_TYPE s = MG_INVALID_SOCKET;
-  do {
-    memset(usa, 0, sizeof(*usa));
-    s = accept(sock, &usa->sa, len);
-  } while (s == MG_INVALID_SOCKET && errno == EINTR);
-  return s;
+/* Constant-time comparison function - secure way to compare long integers */
+/* Returns one if left == right, zero otherwise. */
+MG_UECC_VLI_API mg_uecc_word_t mg_uecc_vli_equal(const mg_uecc_word_t *left,
+                                                 const mg_uecc_word_t *right,
+                                                 wordcount_t num_words) {
+  mg_uecc_word_t diff = 0;
+  wordcount_t i;
+  for (i = num_words - 1; i >= 0; --i) {
+    diff |= (left[i] ^ right[i]);
+  }
+  return (diff == 0);
+}
+
+MG_UECC_VLI_API mg_uecc_word_t mg_uecc_vli_sub(mg_uecc_word_t *result,
+                                               const mg_uecc_word_t *left,
+                                               const mg_uecc_word_t *right,
+                                               wordcount_t num_words);
+
+/* Returns sign of left - right, in constant time. */
+MG_UECC_VLI_API cmpresult_t mg_uecc_vli_cmp(const mg_uecc_word_t *left,
+                                            const mg_uecc_word_t *right,
+                                            wordcount_t num_words) {
+  mg_uecc_word_t tmp[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t neg = !!mg_uecc_vli_sub(tmp, left, right, num_words);
+  mg_uecc_word_t equal = mg_uecc_vli_isZero(tmp, num_words);
+  return (cmpresult_t) (!equal - 2 * neg);
+}
+
+/* Computes vli = vli >> 1. */
+#if !asm_rshift1
+MG_UECC_VLI_API void mg_uecc_vli_rshift1(mg_uecc_word_t *vli,
+                                         wordcount_t num_words) {
+  mg_uecc_word_t *end = vli;
+  mg_uecc_word_t carry = 0;
+
+  vli += num_words;
+  while (vli-- > end) {
+    mg_uecc_word_t temp = *vli;
+    *vli = (temp >> 1) | carry;
+    carry = temp << (MG_UECC_WORD_BITS - 1);
+  }
 }
+#endif /* !asm_rshift1 */
+
+/* Computes result = left + right, returning carry. Can modify in place. */
+#if !asm_add
+MG_UECC_VLI_API mg_uecc_word_t mg_uecc_vli_add(mg_uecc_word_t *result,
+                                               const mg_uecc_word_t *left,
+                                               const mg_uecc_word_t *right,
+                                               wordcount_t num_words) {
+  mg_uecc_word_t carry = 0;
+  wordcount_t i;
+  for (i = 0; i < num_words; ++i) {
+    mg_uecc_word_t sum = left[i] + right[i] + carry;
+    if (sum != left[i]) {
+      carry = (sum < left[i]);
+    }
+    result[i] = sum;
+  }
+  return carry;
+}
+#endif /* !asm_add */
+
+/* Computes result = left - right, returning borrow. Can modify in place. */
+#if !asm_sub
+MG_UECC_VLI_API mg_uecc_word_t mg_uecc_vli_sub(mg_uecc_word_t *result,
+                                               const mg_uecc_word_t *left,
+                                               const mg_uecc_word_t *right,
+                                               wordcount_t num_words) {
+  mg_uecc_word_t borrow = 0;
+  wordcount_t i;
+  for (i = 0; i < num_words; ++i) {
+    mg_uecc_word_t diff = left[i] - right[i] - borrow;
+    if (diff != left[i]) {
+      borrow = (diff > left[i]);
+    }
+    result[i] = diff;
+  }
+  return borrow;
+}
+#endif /* !asm_sub */
+
+#if !asm_mult || (MG_UECC_SQUARE_FUNC && !asm_square) ||               \
+    (MG_UECC_SUPPORTS_secp256k1 && (MG_UECC_OPTIMIZATION_LEVEL > 0) && \
+     ((MG_UECC_WORD_SIZE == 1) || (MG_UECC_WORD_SIZE == 8)))
+static void muladd(mg_uecc_word_t a, mg_uecc_word_t b, mg_uecc_word_t *r0,
+                   mg_uecc_word_t *r1, mg_uecc_word_t *r2) {
+#if MG_UECC_WORD_SIZE == 8
+  uint64_t a0 = a & 0xffffffff;
+  uint64_t a1 = a >> 32;
+  uint64_t b0 = b & 0xffffffff;
+  uint64_t b1 = b >> 32;
+
+  uint64_t i0 = a0 * b0;
+  uint64_t i1 = a0 * b1;
+  uint64_t i2 = a1 * b0;
+  uint64_t i3 = a1 * b1;
+
+  uint64_t p0, p1;
+
+  i2 += (i0 >> 32);
+  i2 += i1;
+  if (i2 < i1) { /* overflow */
+    i3 += 0x100000000;
+  }
 
-static void accept_conn(struct mg_mgr *mgr, struct mg_connection *lsn) {
-  struct mg_connection *c = NULL;
-  union usa usa;
-  socklen_t sa_len = sizeof(usa);
-  MG_SOCKET_TYPE fd = raccept(FD(lsn), &usa, &sa_len);
-  if (fd == MG_INVALID_SOCKET) {
-#if MG_ARCH == MG_ARCH_AZURERTOS
-    // AzureRTOS, in non-block socket mode can mark listening socket readable
-    // even it is not. See comment for 'select' func implementation in
-    // nx_bsd.c That's not an error, just should try later
-    if (MG_SOCKET_ERRNO != EAGAIN)
-#endif
-      MG_ERROR(("%lu accept failed, errno %d", lsn->id, MG_SOCKET_ERRNO));
-#if (MG_ARCH != MG_ARCH_WIN32) && !MG_ENABLE_FREERTOS_TCP && \
-    (MG_ARCH != MG_ARCH_TIRTOS) && !MG_ENABLE_POLL
-  } else if ((long) fd >= FD_SETSIZE) {
-    MG_ERROR(("%ld > %ld", (long) fd, (long) FD_SETSIZE));
-    closesocket(fd);
+  p0 = (i0 & 0xffffffff) | (i2 << 32);
+  p1 = i3 + (i2 >> 32);
+
+  *r0 += p0;
+  *r1 += (p1 + (*r0 < p0));
+  *r2 += ((*r1 < p1) || (*r1 == p1 && *r0 < p0));
+#else
+  mg_uecc_dword_t p = (mg_uecc_dword_t) a * b;
+  mg_uecc_dword_t r01 = ((mg_uecc_dword_t) (*r1) << MG_UECC_WORD_BITS) | *r0;
+  r01 += p;
+  *r2 += (r01 < p);
+  *r1 = (mg_uecc_word_t) (r01 >> MG_UECC_WORD_BITS);
+  *r0 = (mg_uecc_word_t) r01;
 #endif
-  } else if ((c = mg_alloc_conn(mgr)) == NULL) {
-    MG_ERROR(("%lu OOM", lsn->id));
-    closesocket(fd);
-  } else {
-    tomgaddr(&usa, &c->rem, sa_len != sizeof(usa.sin));
-    LIST_ADD_HEAD(struct mg_connection, &mgr->conns, c);
-    c->fd = S2PTR(fd);
-    MG_EPOLL_ADD(c);
-    mg_set_non_blocking_mode(FD(c));
-    setsockopts(c);
-    c->is_accepted = 1;
-    c->is_hexdumping = lsn->is_hexdumping;
-    c->loc = lsn->loc;
-    c->pfn = lsn->pfn;
-    c->pfn_data = lsn->pfn_data;
-    c->fn = lsn->fn;
-    c->fn_data = lsn->fn_data;
-    MG_DEBUG(("%lu %p accepted %I.%hu -> %I.%hu", c->id, c->fd, 4, &c->rem.ip,
-              mg_ntohs(c->rem.port), 4, &c->loc.ip, mg_ntohs(c->loc.port)));
-    mg_call(c, MG_EV_OPEN, NULL);
-    mg_call(c, MG_EV_ACCEPT, NULL);
+}
+#endif /* muladd needed */
+
+#if !asm_mult
+MG_UECC_VLI_API void mg_uecc_vli_mult(mg_uecc_word_t *result,
+                                      const mg_uecc_word_t *left,
+                                      const mg_uecc_word_t *right,
+                                      wordcount_t num_words) {
+  mg_uecc_word_t r0 = 0;
+  mg_uecc_word_t r1 = 0;
+  mg_uecc_word_t r2 = 0;
+  wordcount_t i, k;
+
+  /* Compute each digit of result in sequence, maintaining the carries. */
+  for (k = 0; k < num_words; ++k) {
+    for (i = 0; i <= k; ++i) {
+      muladd(left[i], right[k - i], &r0, &r1, &r2);
+    }
+    result[k] = r0;
+    r0 = r1;
+    r1 = r2;
+    r2 = 0;
   }
+  for (k = num_words; k < num_words * 2 - 1; ++k) {
+    for (i = (wordcount_t) ((k + 1) - num_words); i < num_words; ++i) {
+      muladd(left[i], right[k - i], &r0, &r1, &r2);
+    }
+    result[k] = r0;
+    r0 = r1;
+    r1 = r2;
+    r2 = 0;
+  }
+  result[num_words * 2 - 1] = r0;
 }
+#endif /* !asm_mult */
 
-static bool mg_socketpair(MG_SOCKET_TYPE sp[2], union usa usa[2], bool udp) {
-  MG_SOCKET_TYPE sock;
-  socklen_t n = sizeof(usa[0].sin);
-  bool success = false;
+#if MG_UECC_SQUARE_FUNC
 
-  sock = sp[0] = sp[1] = MG_INVALID_SOCKET;
-  (void) memset(&usa[0], 0, sizeof(usa[0]));
-  usa[0].sin.sin_family = AF_INET;
-  *(uint32_t *) &usa->sin.sin_addr = mg_htonl(0x7f000001U);  // 127.0.0.1
-  usa[1] = usa[0];
+#if !asm_square
+static void mul2add(mg_uecc_word_t a, mg_uecc_word_t b, mg_uecc_word_t *r0,
+                    mg_uecc_word_t *r1, mg_uecc_word_t *r2) {
+#if MG_UECC_WORD_SIZE == 8
+  uint64_t a0 = a & 0xffffffffull;
+  uint64_t a1 = a >> 32;
+  uint64_t b0 = b & 0xffffffffull;
+  uint64_t b1 = b >> 32;
 
-  if (udp && (sp[0] = socket(AF_INET, SOCK_DGRAM, 0)) != MG_INVALID_SOCKET &&
-      (sp[1] = socket(AF_INET, SOCK_DGRAM, 0)) != MG_INVALID_SOCKET &&
-      bind(sp[0], &usa[0].sa, n) == 0 && bind(sp[1], &usa[1].sa, n) == 0 &&
-      getsockname(sp[0], &usa[0].sa, &n) == 0 &&
-      getsockname(sp[1], &usa[1].sa, &n) == 0 &&
-      connect(sp[0], &usa[1].sa, n) == 0 &&
-      connect(sp[1], &usa[0].sa, n) == 0) {
-    success = true;
-  } else if (!udp &&
-             (sock = socket(AF_INET, SOCK_STREAM, 0)) != MG_INVALID_SOCKET &&
-             bind(sock, &usa[0].sa, n) == 0 &&
-             listen(sock, MG_SOCK_LISTEN_BACKLOG_SIZE) == 0 &&
-             getsockname(sock, &usa[0].sa, &n) == 0 &&
-             (sp[0] = socket(AF_INET, SOCK_STREAM, 0)) != MG_INVALID_SOCKET &&
-             connect(sp[0], &usa[0].sa, n) == 0 &&
-             (sp[1] = raccept(sock, &usa[1], &n)) != MG_INVALID_SOCKET) {
-    success = true;
-  }
-  if (success) {
-    mg_set_non_blocking_mode(sp[1]);
-  } else {
-    if (sp[0] != MG_INVALID_SOCKET) closesocket(sp[0]);
-    if (sp[1] != MG_INVALID_SOCKET) closesocket(sp[1]);
-    sp[0] = sp[1] = MG_INVALID_SOCKET;
+  uint64_t i0 = a0 * b0;
+  uint64_t i1 = a0 * b1;
+  uint64_t i2 = a1 * b0;
+  uint64_t i3 = a1 * b1;
+
+  uint64_t p0, p1;
+
+  i2 += (i0 >> 32);
+  i2 += i1;
+  if (i2 < i1) { /* overflow */
+    i3 += 0x100000000ull;
   }
-  if (sock != MG_INVALID_SOCKET) closesocket(sock);
-  return success;
+
+  p0 = (i0 & 0xffffffffull) | (i2 << 32);
+  p1 = i3 + (i2 >> 32);
+
+  *r2 += (p1 >> 63);
+  p1 = (p1 << 1) | (p0 >> 63);
+  p0 <<= 1;
+
+  *r0 += p0;
+  *r1 += (p1 + (*r0 < p0));
+  *r2 += ((*r1 < p1) || (*r1 == p1 && *r0 < p0));
+#else
+  mg_uecc_dword_t p = (mg_uecc_dword_t) a * b;
+  mg_uecc_dword_t r01 = ((mg_uecc_dword_t) (*r1) << MG_UECC_WORD_BITS) | *r0;
+  *r2 += (p >> (MG_UECC_WORD_BITS * 2 - 1));
+  p *= 2;
+  r01 += p;
+  *r2 += (r01 < p);
+  *r1 = r01 >> MG_UECC_WORD_BITS;
+  *r0 = (mg_uecc_word_t) r01;
+#endif
 }
 
-int mg_mkpipe(struct mg_mgr *mgr, mg_event_handler_t fn, void *fn_data,
-              bool udp) {
-  union usa usa[2];
-  MG_SOCKET_TYPE sp[2] = {MG_INVALID_SOCKET, MG_INVALID_SOCKET};
-  struct mg_connection *c = NULL;
-  if (!mg_socketpair(sp, usa, udp)) {
-    MG_ERROR(("Cannot create socket pair"));
-  } else if ((c = mg_wrapfd(mgr, (int) sp[1], fn, fn_data)) == NULL) {
-    closesocket(sp[0]);
-    closesocket(sp[1]);
-    sp[0] = sp[1] = MG_INVALID_SOCKET;
-  } else {
-    tomgaddr(&usa[0], &c->rem, false);
-    MG_DEBUG(("%lu %p pipe %lu", c->id, c->fd, (unsigned long) sp[0]));
+MG_UECC_VLI_API void mg_uecc_vli_square(mg_uecc_word_t *result,
+                                        const mg_uecc_word_t *left,
+                                        wordcount_t num_words) {
+  mg_uecc_word_t r0 = 0;
+  mg_uecc_word_t r1 = 0;
+  mg_uecc_word_t r2 = 0;
+
+  wordcount_t i, k;
+
+  for (k = 0; k < num_words * 2 - 1; ++k) {
+    mg_uecc_word_t min = (k < num_words ? 0 : (k + 1) - num_words);
+    for (i = min; i <= k && i <= k - i; ++i) {
+      if (i < k - i) {
+        mul2add(left[i], left[k - i], &r0, &r1, &r2);
+      } else {
+        muladd(left[i], left[k - i], &r0, &r1, &r2);
+      }
+    }
+    result[k] = r0;
+    r0 = r1;
+    r1 = r2;
+    r2 = 0;
   }
-  return (int) sp[0];
-}
 
-static bool can_read(const struct mg_connection *c) {
-  return c->is_full == false;
+  result[num_words * 2 - 1] = r0;
 }
+#endif /* !asm_square */
 
-static bool can_write(const struct mg_connection *c) {
-  return c->is_connecting || (c->send.len > 0 && c->is_tls_hs == 0);
-}
+#else /* MG_UECC_SQUARE_FUNC */
 
-static bool skip_iotest(const struct mg_connection *c) {
-  return (c->is_closing || c->is_resolving || FD(c) == MG_INVALID_SOCKET) ||
-         (can_read(c) == false && can_write(c) == false);
+#if MG_UECC_ENABLE_VLI_API
+MG_UECC_VLI_API void mg_uecc_vli_square(mg_uecc_word_t *result,
+                                        const mg_uecc_word_t *left,
+                                        wordcount_t num_words) {
+  mg_uecc_vli_mult(result, left, left, num_words);
 }
+#endif /* MG_UECC_ENABLE_VLI_API */
 
-static void mg_iotest(struct mg_mgr *mgr, int ms) {
-#if MG_ENABLE_FREERTOS_TCP
-  struct mg_connection *c;
-  for (c = mgr->conns; c != NULL; c = c->next) {
-    c->is_readable = c->is_writable = 0;
-    if (skip_iotest(c)) continue;
-    if (can_read(c))
-      FreeRTOS_FD_SET(c->fd, mgr->ss, eSELECT_READ | eSELECT_EXCEPT);
-    if (can_write(c)) FreeRTOS_FD_SET(c->fd, mgr->ss, eSELECT_WRITE);
-  }
-  FreeRTOS_select(mgr->ss, pdMS_TO_TICKS(ms));
-  for (c = mgr->conns; c != NULL; c = c->next) {
-    EventBits_t bits = FreeRTOS_FD_ISSET(c->fd, mgr->ss);
-    c->is_readable = bits & (eSELECT_READ | eSELECT_EXCEPT) ? 1U : 0;
-    c->is_writable = bits & eSELECT_WRITE ? 1U : 0;
-    FreeRTOS_FD_CLR(c->fd, mgr->ss,
-                    eSELECT_READ | eSELECT_EXCEPT | eSELECT_WRITE);
+#endif /* MG_UECC_SQUARE_FUNC */
+
+/* Computes result = (left + right) % mod.
+   Assumes that left < mod and right < mod, and that result does not overlap
+   mod. */
+MG_UECC_VLI_API void mg_uecc_vli_modAdd(mg_uecc_word_t *result,
+                                        const mg_uecc_word_t *left,
+                                        const mg_uecc_word_t *right,
+                                        const mg_uecc_word_t *mod,
+                                        wordcount_t num_words) {
+  mg_uecc_word_t carry = mg_uecc_vli_add(result, left, right, num_words);
+  if (carry || mg_uecc_vli_cmp_unsafe(mod, result, num_words) != 1) {
+    /* result > mod (result = mod + remainder), so subtract mod to get
+     * remainder. */
+    mg_uecc_vli_sub(result, result, mod, num_words);
   }
-#elif MG_ENABLE_EPOLL
-  size_t max = 1;
-  for (struct mg_connection *c = mgr->conns; c != NULL; c = c->next) {
-    c->is_readable = c->is_writable = 0;
-    if (mg_tls_pending(c) > 0) ms = 1, c->is_readable = 1;
-    if (can_write(c)) MG_EPOLL_MOD(c, 1);
-    max++;
+}
+
+/* Computes result = (left - right) % mod.
+   Assumes that left < mod and right < mod, and that result does not overlap
+   mod. */
+MG_UECC_VLI_API void mg_uecc_vli_modSub(mg_uecc_word_t *result,
+                                        const mg_uecc_word_t *left,
+                                        const mg_uecc_word_t *right,
+                                        const mg_uecc_word_t *mod,
+                                        wordcount_t num_words) {
+  mg_uecc_word_t l_borrow = mg_uecc_vli_sub(result, left, right, num_words);
+  if (l_borrow) {
+    /* In this case, result == -diff == (max int) - diff. Since -x % d == d - x,
+       we can get the correct result from result + mod (with overflow). */
+    mg_uecc_vli_add(result, result, mod, num_words);
   }
-  struct epoll_event *evs = (struct epoll_event *) alloca(max * sizeof(evs[0]));
-  int n = epoll_wait(mgr->epoll_fd, evs, (int) max, ms);
-  for (int i = 0; i < n; i++) {
-    struct mg_connection *c = (struct mg_connection *) evs[i].data.ptr;
-    if (evs[i].events & EPOLLERR) {
-      mg_error(c, "socket error");
-    } else if (c->is_readable == 0) {
-      bool rd = evs[i].events & (EPOLLIN | EPOLLHUP);
-      bool wr = evs[i].events & EPOLLOUT;
-      c->is_readable = can_read(c) && rd ? 1U : 0;
-      c->is_writable = can_write(c) && wr ? 1U : 0;
+}
+
+/* Computes result = product % mod, where product is 2N words long. */
+/* Currently only designed to work for curve_p or curve_n. */
+MG_UECC_VLI_API void mg_uecc_vli_mmod(mg_uecc_word_t *result,
+                                      mg_uecc_word_t *product,
+                                      const mg_uecc_word_t *mod,
+                                      wordcount_t num_words) {
+  mg_uecc_word_t mod_multiple[2 * MG_UECC_MAX_WORDS];
+  mg_uecc_word_t tmp[2 * MG_UECC_MAX_WORDS];
+  mg_uecc_word_t *v[2] = {tmp, product};
+  mg_uecc_word_t index;
+
+  /* Shift mod so its highest set bit is at the maximum position. */
+  bitcount_t shift = (bitcount_t) ((num_words * 2 * MG_UECC_WORD_BITS) -
+                                   mg_uecc_vli_numBits(mod, num_words));
+  wordcount_t word_shift = (wordcount_t) (shift / MG_UECC_WORD_BITS);
+  wordcount_t bit_shift = (wordcount_t) (shift % MG_UECC_WORD_BITS);
+  mg_uecc_word_t carry = 0;
+  mg_uecc_vli_clear(mod_multiple, word_shift);
+  if (bit_shift > 0) {
+    for (index = 0; index < (mg_uecc_word_t) num_words; ++index) {
+      mod_multiple[(mg_uecc_word_t) word_shift + index] =
+          (mg_uecc_word_t) (mod[index] << bit_shift) | carry;
+      carry = mod[index] >> (MG_UECC_WORD_BITS - bit_shift);
     }
+  } else {
+    mg_uecc_vli_set(mod_multiple + word_shift, mod, num_words);
   }
-  (void) skip_iotest;
-#elif MG_ENABLE_POLL
-  nfds_t n = 0;
-  for (struct mg_connection *c = mgr->conns; c != NULL; c = c->next) n++;
-  struct pollfd *fds = (struct pollfd *) alloca(n * sizeof(fds[0]));
-  memset(fds, 0, n * sizeof(fds[0]));
-  n = 0;
-  for (struct mg_connection *c = mgr->conns; c != NULL; c = c->next) {
-    c->is_readable = c->is_writable = 0;
-    if (skip_iotest(c)) {
-      // Socket not valid, ignore
-    } else if (mg_tls_pending(c) > 0) {
-      ms = 1;  // Don't wait if TLS is ready
-    } else {
-      fds[n].fd = FD(c);
-      if (can_read(c)) fds[n].events |= POLLIN;
-      if (can_write(c)) fds[n].events |= POLLOUT;
-      n++;
+
+  for (index = 1; shift >= 0; --shift) {
+    mg_uecc_word_t borrow = 0;
+    wordcount_t i;
+    for (i = 0; i < num_words * 2; ++i) {
+      mg_uecc_word_t diff = v[index][i] - mod_multiple[i] - borrow;
+      if (diff != v[index][i]) {
+        borrow = (diff > v[index][i]);
+      }
+      v[1 - index][i] = diff;
     }
+    index = !(index ^ borrow); /* Swap the index if there was no borrow */
+    mg_uecc_vli_rshift1(mod_multiple, num_words);
+    mod_multiple[num_words - 1] |= mod_multiple[num_words]
+                                   << (MG_UECC_WORD_BITS - 1);
+    mg_uecc_vli_rshift1(mod_multiple + num_words, num_words);
+  }
+  mg_uecc_vli_set(result, v[index], num_words);
+}
+
+/* Computes result = (left * right) % mod. */
+MG_UECC_VLI_API void mg_uecc_vli_modMult(mg_uecc_word_t *result,
+                                         const mg_uecc_word_t *left,
+                                         const mg_uecc_word_t *right,
+                                         const mg_uecc_word_t *mod,
+                                         wordcount_t num_words) {
+  mg_uecc_word_t product[2 * MG_UECC_MAX_WORDS];
+  mg_uecc_vli_mult(product, left, right, num_words);
+  mg_uecc_vli_mmod(result, product, mod, num_words);
+}
+
+MG_UECC_VLI_API void mg_uecc_vli_modMult_fast(mg_uecc_word_t *result,
+                                              const mg_uecc_word_t *left,
+                                              const mg_uecc_word_t *right,
+                                              MG_UECC_Curve curve) {
+  mg_uecc_word_t product[2 * MG_UECC_MAX_WORDS];
+  mg_uecc_vli_mult(product, left, right, curve->num_words);
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0)
+  curve->mmod_fast(result, product);
+#else
+  mg_uecc_vli_mmod(result, product, curve->p, curve->num_words);
+#endif
+}
+
+#if MG_UECC_SQUARE_FUNC
+
+#if MG_UECC_ENABLE_VLI_API
+/* Computes result = left^2 % mod. */
+MG_UECC_VLI_API void mg_uecc_vli_modSquare(mg_uecc_word_t *result,
+                                           const mg_uecc_word_t *left,
+                                           const mg_uecc_word_t *mod,
+                                           wordcount_t num_words) {
+  mg_uecc_word_t product[2 * MG_UECC_MAX_WORDS];
+  mg_uecc_vli_square(product, left, num_words);
+  mg_uecc_vli_mmod(result, product, mod, num_words);
+}
+#endif /* MG_UECC_ENABLE_VLI_API */
+
+MG_UECC_VLI_API void mg_uecc_vli_modSquare_fast(mg_uecc_word_t *result,
+                                                const mg_uecc_word_t *left,
+                                                MG_UECC_Curve curve) {
+  mg_uecc_word_t product[2 * MG_UECC_MAX_WORDS];
+  mg_uecc_vli_square(product, left, curve->num_words);
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0)
+  curve->mmod_fast(result, product);
+#else
+  mg_uecc_vli_mmod(result, product, curve->p, curve->num_words);
+#endif
+}
+
+#else /* MG_UECC_SQUARE_FUNC */
+
+#if MG_UECC_ENABLE_VLI_API
+MG_UECC_VLI_API void mg_uecc_vli_modSquare(mg_uecc_word_t *result,
+                                           const mg_uecc_word_t *left,
+                                           const mg_uecc_word_t *mod,
+                                           wordcount_t num_words) {
+  mg_uecc_vli_modMult(result, left, left, mod, num_words);
+}
+#endif /* MG_UECC_ENABLE_VLI_API */
+
+MG_UECC_VLI_API void mg_uecc_vli_modSquare_fast(mg_uecc_word_t *result,
+                                                const mg_uecc_word_t *left,
+                                                MG_UECC_Curve curve) {
+  mg_uecc_vli_modMult_fast(result, left, left, curve);
+}
+
+#endif /* MG_UECC_SQUARE_FUNC */
+
+#define EVEN(vli) (!(vli[0] & 1))
+static void vli_modInv_update(mg_uecc_word_t *uv, const mg_uecc_word_t *mod,
+                              wordcount_t num_words) {
+  mg_uecc_word_t carry = 0;
+  if (!EVEN(uv)) {
+    carry = mg_uecc_vli_add(uv, uv, mod, num_words);
   }
+  mg_uecc_vli_rshift1(uv, num_words);
+  if (carry) {
+    uv[num_words - 1] |= HIGH_BIT_SET;
+  }
+}
 
-  // MG_INFO(("poll n=%d ms=%d", (int) n, ms));
-  if (poll(fds, n, ms) < 0) {
-#if MG_ARCH == MG_ARCH_WIN32
-    if (n == 0) Sleep(ms);  // On Windows, poll fails if no sockets
-#endif
-    memset(fds, 0, n * sizeof(fds[0]));
+/* Computes result = (1 / input) % mod. All VLIs are the same size.
+   See "From Euclid's GCD to Montgomery Multiplication to the Great Divide" */
+MG_UECC_VLI_API void mg_uecc_vli_modInv(mg_uecc_word_t *result,
+                                        const mg_uecc_word_t *input,
+                                        const mg_uecc_word_t *mod,
+                                        wordcount_t num_words) {
+  mg_uecc_word_t a[MG_UECC_MAX_WORDS], b[MG_UECC_MAX_WORDS],
+      u[MG_UECC_MAX_WORDS], v[MG_UECC_MAX_WORDS];
+  cmpresult_t cmpResult;
+
+  if (mg_uecc_vli_isZero(input, num_words)) {
+    mg_uecc_vli_clear(result, num_words);
+    return;
   }
-  n = 0;
-  for (struct mg_connection *c = mgr->conns; c != NULL; c = c->next) {
-    if (skip_iotest(c)) {
-      // Socket not valid, ignore
-    } else if (mg_tls_pending(c) > 0) {
-      c->is_readable = 1;
+
+  mg_uecc_vli_set(a, input, num_words);
+  mg_uecc_vli_set(b, mod, num_words);
+  mg_uecc_vli_clear(u, num_words);
+  u[0] = 1;
+  mg_uecc_vli_clear(v, num_words);
+  while ((cmpResult = mg_uecc_vli_cmp_unsafe(a, b, num_words)) != 0) {
+    if (EVEN(a)) {
+      mg_uecc_vli_rshift1(a, num_words);
+      vli_modInv_update(u, mod, num_words);
+    } else if (EVEN(b)) {
+      mg_uecc_vli_rshift1(b, num_words);
+      vli_modInv_update(v, mod, num_words);
+    } else if (cmpResult > 0) {
+      mg_uecc_vli_sub(a, a, b, num_words);
+      mg_uecc_vli_rshift1(a, num_words);
+      if (mg_uecc_vli_cmp_unsafe(u, v, num_words) < 0) {
+        mg_uecc_vli_add(u, u, mod, num_words);
+      }
+      mg_uecc_vli_sub(u, u, v, num_words);
+      vli_modInv_update(u, mod, num_words);
     } else {
-      if (fds[n].revents & POLLERR) {
-        mg_error(c, "socket error");
-      } else {
-        c->is_readable =
-            (unsigned) (fds[n].revents & (POLLIN | POLLHUP) ? 1 : 0);
-        c->is_writable = (unsigned) (fds[n].revents & POLLOUT ? 1 : 0);
+      mg_uecc_vli_sub(b, b, a, num_words);
+      mg_uecc_vli_rshift1(b, num_words);
+      if (mg_uecc_vli_cmp_unsafe(v, u, num_words) < 0) {
+        mg_uecc_vli_add(v, v, mod, num_words);
       }
-      n++;
+      mg_uecc_vli_sub(v, v, u, num_words);
+      vli_modInv_update(v, mod, num_words);
     }
   }
-#else
-  struct timeval tv = {ms / 1000, (ms % 1000) * 1000}, tv_zero = {0, 0};
-  struct mg_connection *c;
-  fd_set rset, wset, eset;
-  MG_SOCKET_TYPE maxfd = 0;
-  int rc;
+  mg_uecc_vli_set(result, u, num_words);
+}
 
-  FD_ZERO(&rset);
-  FD_ZERO(&wset);
-  FD_ZERO(&eset);
-  for (c = mgr->conns; c != NULL; c = c->next) {
-    c->is_readable = c->is_writable = 0;
-    if (skip_iotest(c)) continue;
-    FD_SET(FD(c), &eset);
-    if (can_read(c)) FD_SET(FD(c), &rset);
-    if (can_write(c)) FD_SET(FD(c), &wset);
-    if (mg_tls_pending(c) > 0) tv = tv_zero;
-    if (FD(c) > maxfd) maxfd = FD(c);
+/* ------ Point operations ------ */
+
+/* Copyright 2015, Kenneth MacKay. Licensed under the BSD 2-clause license. */
+
+#ifndef _UECC_CURVE_SPECIFIC_H_
+#define _UECC_CURVE_SPECIFIC_H_
+
+#define num_bytes_secp160r1 20
+#define num_bytes_secp192r1 24
+#define num_bytes_secp224r1 28
+#define num_bytes_secp256r1 32
+#define num_bytes_secp256k1 32
+
+#if (MG_UECC_WORD_SIZE == 1)
+
+#define num_words_secp160r1 20
+#define num_words_secp192r1 24
+#define num_words_secp224r1 28
+#define num_words_secp256r1 32
+#define num_words_secp256k1 32
+
+#define BYTES_TO_WORDS_8(a, b, c, d, e, f, g, h) \
+  0x##a, 0x##b, 0x##c, 0x##d, 0x##e, 0x##f, 0x##g, 0x##h
+#define BYTES_TO_WORDS_4(a, b, c, d) 0x##a, 0x##b, 0x##c, 0x##d
+
+#elif (MG_UECC_WORD_SIZE == 4)
+
+#define num_words_secp160r1 5
+#define num_words_secp192r1 6
+#define num_words_secp224r1 7
+#define num_words_secp256r1 8
+#define num_words_secp256k1 8
+
+#define BYTES_TO_WORDS_8(a, b, c, d, e, f, g, h) 0x##d##c##b##a, 0x##h##g##f##e
+#define BYTES_TO_WORDS_4(a, b, c, d) 0x##d##c##b##a
+
+#elif (MG_UECC_WORD_SIZE == 8)
+
+#define num_words_secp160r1 3
+#define num_words_secp192r1 3
+#define num_words_secp224r1 4
+#define num_words_secp256r1 4
+#define num_words_secp256k1 4
+
+#define BYTES_TO_WORDS_8(a, b, c, d, e, f, g, h) 0x##h##g##f##e##d##c##b##a##U
+#define BYTES_TO_WORDS_4(a, b, c, d) 0x##d##c##b##a##U
+
+#endif /* MG_UECC_WORD_SIZE */
+
+#if MG_UECC_SUPPORTS_secp160r1 || MG_UECC_SUPPORTS_secp192r1 || \
+    MG_UECC_SUPPORTS_secp224r1 || MG_UECC_SUPPORTS_secp256r1
+static void double_jacobian_default(mg_uecc_word_t *X1, mg_uecc_word_t *Y1,
+                                    mg_uecc_word_t *Z1, MG_UECC_Curve curve) {
+  /* t1 = X, t2 = Y, t3 = Z */
+  mg_uecc_word_t t4[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t t5[MG_UECC_MAX_WORDS];
+  wordcount_t num_words = curve->num_words;
+
+  if (mg_uecc_vli_isZero(Z1, num_words)) {
+    return;
   }
 
-  if ((rc = select((int) maxfd + 1, &rset, &wset, &eset, &tv)) < 0) {
-#if MG_ARCH == MG_ARCH_WIN32
-    if (maxfd == 0) Sleep(ms);  // On Windows, select fails if no sockets
+  mg_uecc_vli_modSquare_fast(t4, Y1, curve);   /* t4 = y1^2 */
+  mg_uecc_vli_modMult_fast(t5, X1, t4, curve); /* t5 = x1*y1^2 = A */
+  mg_uecc_vli_modSquare_fast(t4, t4, curve);   /* t4 = y1^4 */
+  mg_uecc_vli_modMult_fast(Y1, Y1, Z1, curve); /* t2 = y1*z1 = z3 */
+  mg_uecc_vli_modSquare_fast(Z1, Z1, curve);   /* t3 = z1^2 */
+
+  mg_uecc_vli_modAdd(X1, X1, Z1, curve->p, num_words); /* t1 = x1 + z1^2 */
+  mg_uecc_vli_modAdd(Z1, Z1, Z1, curve->p, num_words); /* t3 = 2*z1^2 */
+  mg_uecc_vli_modSub(Z1, X1, Z1, curve->p, num_words); /* t3 = x1 - z1^2 */
+  mg_uecc_vli_modMult_fast(X1, X1, Z1, curve);         /* t1 = x1^2 - z1^4 */
+
+  mg_uecc_vli_modAdd(Z1, X1, X1, curve->p,
+                     num_words); /* t3 = 2*(x1^2 - z1^4) */
+  mg_uecc_vli_modAdd(X1, X1, Z1, curve->p,
+                     num_words); /* t1 = 3*(x1^2 - z1^4) */
+  if (mg_uecc_vli_testBit(X1, 0)) {
+    mg_uecc_word_t l_carry = mg_uecc_vli_add(X1, X1, curve->p, num_words);
+    mg_uecc_vli_rshift1(X1, num_words);
+    X1[num_words - 1] |= l_carry << (MG_UECC_WORD_BITS - 1);
+  } else {
+    mg_uecc_vli_rshift1(X1, num_words);
+  }
+  /* t1 = 3/2*(x1^2 - z1^4) = B */
+
+  mg_uecc_vli_modSquare_fast(Z1, X1, curve);           /* t3 = B^2 */
+  mg_uecc_vli_modSub(Z1, Z1, t5, curve->p, num_words); /* t3 = B^2 - A */
+  mg_uecc_vli_modSub(Z1, Z1, t5, curve->p, num_words); /* t3 = B^2 - 2A = x3 */
+  mg_uecc_vli_modSub(t5, t5, Z1, curve->p, num_words); /* t5 = A - x3 */
+  mg_uecc_vli_modMult_fast(X1, X1, t5, curve);         /* t1 = B * (A - x3) */
+  mg_uecc_vli_modSub(t4, X1, t4, curve->p,
+                     num_words); /* t4 = B * (A - x3) - y1^4 = y3 */
+
+  mg_uecc_vli_set(X1, Z1, num_words);
+  mg_uecc_vli_set(Z1, Y1, num_words);
+  mg_uecc_vli_set(Y1, t4, num_words);
+}
+
+/* Computes result = x^3 + ax + b. result must not overlap x. */
+static void x_side_default(mg_uecc_word_t *result, const mg_uecc_word_t *x,
+                           MG_UECC_Curve curve) {
+  mg_uecc_word_t _3[MG_UECC_MAX_WORDS] = {3}; /* -a = 3 */
+  wordcount_t num_words = curve->num_words;
+
+  mg_uecc_vli_modSquare_fast(result, x, curve);                /* r = x^2 */
+  mg_uecc_vli_modSub(result, result, _3, curve->p, num_words); /* r = x^2 - 3 */
+  mg_uecc_vli_modMult_fast(result, result, x, curve); /* r = x^3 - 3x */
+  mg_uecc_vli_modAdd(result, result, curve->b, curve->p,
+                     num_words); /* r = x^3 - 3x + b */
+}
+#endif /* MG_UECC_SUPPORTS_secp... */
+
+#if MG_UECC_SUPPORT_COMPRESSED_POINT
+#if MG_UECC_SUPPORTS_secp160r1 || MG_UECC_SUPPORTS_secp192r1 || \
+    MG_UECC_SUPPORTS_secp256r1 || MG_UECC_SUPPORTS_secp256k1
+/* Compute a = sqrt(a) (mod curve_p). */
+static void mod_sqrt_default(mg_uecc_word_t *a, MG_UECC_Curve curve) {
+  bitcount_t i;
+  mg_uecc_word_t p1[MG_UECC_MAX_WORDS] = {1};
+  mg_uecc_word_t l_result[MG_UECC_MAX_WORDS] = {1};
+  wordcount_t num_words = curve->num_words;
+
+  /* When curve->p == 3 (mod 4), we can compute
+     sqrt(a) = a^((curve->p + 1) / 4) (mod curve->p). */
+  mg_uecc_vli_add(p1, curve->p, p1, num_words); /* p1 = curve_p + 1 */
+  for (i = mg_uecc_vli_numBits(p1, num_words) - 1; i > 1; --i) {
+    mg_uecc_vli_modSquare_fast(l_result, l_result, curve);
+    if (mg_uecc_vli_testBit(p1, i)) {
+      mg_uecc_vli_modMult_fast(l_result, l_result, a, curve);
+    }
+  }
+  mg_uecc_vli_set(a, l_result, num_words);
+}
+#endif /* MG_UECC_SUPPORTS_secp... */
+#endif /* MG_UECC_SUPPORT_COMPRESSED_POINT */
+
+#if MG_UECC_SUPPORTS_secp160r1
+
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0)
+static void vli_mmod_fast_secp160r1(mg_uecc_word_t *result,
+                                    mg_uecc_word_t *product);
+#endif
+
+static const struct MG_UECC_Curve_t curve_secp160r1 = {
+    num_words_secp160r1,
+    num_bytes_secp160r1,
+    161, /* num_n_bits */
+    {BYTES_TO_WORDS_8(FF, FF, FF, 7F, FF, FF, FF, FF),
+     BYTES_TO_WORDS_8(FF, FF, FF, FF, FF, FF, FF, FF),
+     BYTES_TO_WORDS_4(FF, FF, FF, FF)},
+    {BYTES_TO_WORDS_8(57, 22, 75, CA, D3, AE, 27, F9),
+     BYTES_TO_WORDS_8(C8, F4, 01, 00, 00, 00, 00, 00),
+     BYTES_TO_WORDS_8(00, 00, 00, 00, 01, 00, 00, 00)},
+    {BYTES_TO_WORDS_8(82, FC, CB, 13, B9, 8B, C3, 68),
+     BYTES_TO_WORDS_8(89, 69, 64, 46, 28, 73, F5, 8E),
+     BYTES_TO_WORDS_4(68, B5, 96, 4A),
+
+     BYTES_TO_WORDS_8(32, FB, C5, 7A, 37, 51, 23, 04),
+     BYTES_TO_WORDS_8(12, C9, DC, 59, 7D, 94, 68, 31),
+     BYTES_TO_WORDS_4(55, 28, A6, 23)},
+    {BYTES_TO_WORDS_8(45, FA, 65, C5, AD, D4, D4, 81),
+     BYTES_TO_WORDS_8(9F, F8, AC, 65, 8B, 7A, BD, 54),
+     BYTES_TO_WORDS_4(FC, BE, 97, 1C)},
+    &double_jacobian_default,
+#if MG_UECC_SUPPORT_COMPRESSED_POINT
+    &mod_sqrt_default,
+#endif
+    &x_side_default,
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0)
+    &vli_mmod_fast_secp160r1
+#endif
+};
+
+MG_UECC_Curve mg_uecc_secp160r1(void) {
+  return &curve_secp160r1;
+}
+
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0 && !asm_mmod_fast_secp160r1)
+/* Computes result = product % curve_p
+    see http://www.isys.uni-klu.ac.at/PDF/2001-0126-MT.pdf page 354
+
+    Note that this only works if log2(omega) < log2(p) / 2 */
+static void omega_mult_secp160r1(mg_uecc_word_t *result,
+                                 const mg_uecc_word_t *right);
+#if MG_UECC_WORD_SIZE == 8
+static void vli_mmod_fast_secp160r1(mg_uecc_word_t *result,
+                                    mg_uecc_word_t *product) {
+  mg_uecc_word_t tmp[2 * num_words_secp160r1];
+  mg_uecc_word_t copy;
+
+  mg_uecc_vli_clear(tmp, num_words_secp160r1);
+  mg_uecc_vli_clear(tmp + num_words_secp160r1, num_words_secp160r1);
+
+  omega_mult_secp160r1(tmp,
+                       product + num_words_secp160r1 - 1); /* (Rq, q) = q * c */
+
+  product[num_words_secp160r1 - 1] &= 0xffffffff;
+  copy = tmp[num_words_secp160r1 - 1];
+  tmp[num_words_secp160r1 - 1] &= 0xffffffff;
+  mg_uecc_vli_add(result, product, tmp,
+                  num_words_secp160r1); /* (C, r) = r + q */
+  mg_uecc_vli_clear(product, num_words_secp160r1);
+  tmp[num_words_secp160r1 - 1] = copy;
+  omega_mult_secp160r1(product, tmp + num_words_secp160r1 - 1); /* Rq*c */
+  mg_uecc_vli_add(result, result, product,
+                  num_words_secp160r1); /* (C1, r) = r + Rq*c */
+
+  while (mg_uecc_vli_cmp_unsafe(result, curve_secp160r1.p,
+                                num_words_secp160r1) > 0) {
+    mg_uecc_vli_sub(result, result, curve_secp160r1.p, num_words_secp160r1);
+  }
+}
+
+static void omega_mult_secp160r1(uint64_t *result, const uint64_t *right) {
+  uint32_t carry;
+  unsigned i;
+
+  /* Multiply by (2^31 + 1). */
+  carry = 0;
+  for (i = 0; i < num_words_secp160r1; ++i) {
+    uint64_t tmp = (right[i] >> 32) | (right[i + 1] << 32);
+    result[i] = (tmp << 31) + tmp + carry;
+    carry = (tmp >> 33) + (result[i] < tmp || (carry && result[i] == tmp));
+  }
+  result[i] = carry;
+}
 #else
-    MG_ERROR(("select: %d %d", rc, MG_SOCKET_ERRNO));
+static void vli_mmod_fast_secp160r1(mg_uecc_word_t *result,
+                                    mg_uecc_word_t *product) {
+  mg_uecc_word_t tmp[2 * num_words_secp160r1];
+  mg_uecc_word_t carry;
+
+  mg_uecc_vli_clear(tmp, num_words_secp160r1);
+  mg_uecc_vli_clear(tmp + num_words_secp160r1, num_words_secp160r1);
+
+  omega_mult_secp160r1(tmp,
+                       product + num_words_secp160r1); /* (Rq, q) = q * c */
+
+  carry = mg_uecc_vli_add(result, product, tmp,
+                          num_words_secp160r1); /* (C, r) = r + q */
+  mg_uecc_vli_clear(product, num_words_secp160r1);
+  omega_mult_secp160r1(product, tmp + num_words_secp160r1); /* Rq*c */
+  carry += mg_uecc_vli_add(result, result, product,
+                           num_words_secp160r1); /* (C1, r) = r + Rq*c */
+
+  while (carry > 0) {
+    --carry;
+    mg_uecc_vli_sub(result, result, curve_secp160r1.p, num_words_secp160r1);
+  }
+  if (mg_uecc_vli_cmp_unsafe(result, curve_secp160r1.p, num_words_secp160r1) >
+      0) {
+    mg_uecc_vli_sub(result, result, curve_secp160r1.p, num_words_secp160r1);
+  }
+}
 #endif
-    FD_ZERO(&rset);
-    FD_ZERO(&wset);
-    FD_ZERO(&eset);
+
+#if MG_UECC_WORD_SIZE == 1
+static void omega_mult_secp160r1(uint8_t *result, const uint8_t *right) {
+  uint8_t carry;
+  uint8_t i;
+
+  /* Multiply by (2^31 + 1). */
+  mg_uecc_vli_set(result + 4, right, num_words_secp160r1); /* 2^32 */
+  mg_uecc_vli_rshift1(result + 4, num_words_secp160r1);    /* 2^31 */
+  result[3] = right[0] << 7; /* get last bit from shift */
+
+  carry = mg_uecc_vli_add(result, result, right,
+                          num_words_secp160r1); /* 2^31 + 1 */
+  for (i = num_words_secp160r1; carry; ++i) {
+    uint16_t sum = (uint16_t) result[i] + carry;
+    result[i] = (uint8_t) sum;
+    carry = sum >> 8;
   }
+}
+#elif MG_UECC_WORD_SIZE == 4
+static void omega_mult_secp160r1(uint32_t *result, const uint32_t *right) {
+  uint32_t carry;
+  unsigned i;
 
-  for (c = mgr->conns; c != NULL; c = c->next) {
-    if (FD(c) != MG_INVALID_SOCKET && FD_ISSET(FD(c), &eset)) {
-      mg_error(c, "socket error");
-    } else {
-      c->is_readable = FD(c) != MG_INVALID_SOCKET && FD_ISSET(FD(c), &rset);
-      c->is_writable = FD(c) != MG_INVALID_SOCKET && FD_ISSET(FD(c), &wset);
-      if (mg_tls_pending(c) > 0) c->is_readable = 1;
-    }
+  /* Multiply by (2^31 + 1). */
+  mg_uecc_vli_set(result + 1, right, num_words_secp160r1); /* 2^32 */
+  mg_uecc_vli_rshift1(result + 1, num_words_secp160r1);    /* 2^31 */
+  result[0] = right[0] << 31; /* get last bit from shift */
+
+  carry = mg_uecc_vli_add(result, result, right,
+                          num_words_secp160r1); /* 2^31 + 1 */
+  for (i = num_words_secp160r1; carry; ++i) {
+    uint64_t sum = (uint64_t) result[i] + carry;
+    result[i] = (uint32_t) sum;
+    carry = sum >> 32;
   }
+}
+#endif /* MG_UECC_WORD_SIZE */
+#endif /* (MG_UECC_OPTIMIZATION_LEVEL > 0 && !asm_mmod_fast_secp160r1) */
+
+#endif /* MG_UECC_SUPPORTS_secp160r1 */
+
+#if MG_UECC_SUPPORTS_secp192r1
+
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0)
+static void vli_mmod_fast_secp192r1(mg_uecc_word_t *result,
+                                    mg_uecc_word_t *product);
 #endif
+
+static const struct MG_UECC_Curve_t curve_secp192r1 = {
+    num_words_secp192r1,
+    num_bytes_secp192r1,
+    192, /* num_n_bits */
+    {BYTES_TO_WORDS_8(FF, FF, FF, FF, FF, FF, FF, FF),
+     BYTES_TO_WORDS_8(FE, FF, FF, FF, FF, FF, FF, FF),
+     BYTES_TO_WORDS_8(FF, FF, FF, FF, FF, FF, FF, FF)},
+    {BYTES_TO_WORDS_8(31, 28, D2, B4, B1, C9, 6B, 14),
+     BYTES_TO_WORDS_8(36, F8, DE, 99, FF, FF, FF, FF),
+     BYTES_TO_WORDS_8(FF, FF, FF, FF, FF, FF, FF, FF)},
+    {BYTES_TO_WORDS_8(12, 10, FF, 82, FD, 0A, FF, F4),
+     BYTES_TO_WORDS_8(00, 88, A1, 43, EB, 20, BF, 7C),
+     BYTES_TO_WORDS_8(F6, 90, 30, B0, 0E, A8, 8D, 18),
+
+     BYTES_TO_WORDS_8(11, 48, 79, 1E, A1, 77, F9, 73),
+     BYTES_TO_WORDS_8(D5, CD, 24, 6B, ED, 11, 10, 63),
+     BYTES_TO_WORDS_8(78, DA, C8, FF, 95, 2B, 19, 07)},
+    {BYTES_TO_WORDS_8(B1, B9, 46, C1, EC, DE, B8, FE),
+     BYTES_TO_WORDS_8(49, 30, 24, 72, AB, E9, A7, 0F),
+     BYTES_TO_WORDS_8(E7, 80, 9C, E5, 19, 05, 21, 64)},
+    &double_jacobian_default,
+#if MG_UECC_SUPPORT_COMPRESSED_POINT
+    &mod_sqrt_default,
+#endif
+    &x_side_default,
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0)
+    &vli_mmod_fast_secp192r1
+#endif
+};
+
+MG_UECC_Curve mg_uecc_secp192r1(void) {
+  return &curve_secp192r1;
 }
 
-void mg_mgr_poll(struct mg_mgr *mgr, int ms) {
-  struct mg_connection *c, *tmp;
-  uint64_t now;
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0)
+/* Computes result = product % curve_p.
+   See algorithm 5 and 6 from http://www.isys.uni-klu.ac.at/PDF/2001-0126-MT.pdf
+ */
+#if MG_UECC_WORD_SIZE == 1
+static void vli_mmod_fast_secp192r1(uint8_t *result, uint8_t *product) {
+  uint8_t tmp[num_words_secp192r1];
+  uint8_t carry;
+
+  mg_uecc_vli_set(result, product, num_words_secp192r1);
+
+  mg_uecc_vli_set(tmp, &product[24], num_words_secp192r1);
+  carry = mg_uecc_vli_add(result, result, tmp, num_words_secp192r1);
+
+  tmp[0] = tmp[1] = tmp[2] = tmp[3] = tmp[4] = tmp[5] = tmp[6] = tmp[7] = 0;
+  tmp[8] = product[24];
+  tmp[9] = product[25];
+  tmp[10] = product[26];
+  tmp[11] = product[27];
+  tmp[12] = product[28];
+  tmp[13] = product[29];
+  tmp[14] = product[30];
+  tmp[15] = product[31];
+  tmp[16] = product[32];
+  tmp[17] = product[33];
+  tmp[18] = product[34];
+  tmp[19] = product[35];
+  tmp[20] = product[36];
+  tmp[21] = product[37];
+  tmp[22] = product[38];
+  tmp[23] = product[39];
+  carry += mg_uecc_vli_add(result, result, tmp, num_words_secp192r1);
+
+  tmp[0] = tmp[8] = product[40];
+  tmp[1] = tmp[9] = product[41];
+  tmp[2] = tmp[10] = product[42];
+  tmp[3] = tmp[11] = product[43];
+  tmp[4] = tmp[12] = product[44];
+  tmp[5] = tmp[13] = product[45];
+  tmp[6] = tmp[14] = product[46];
+  tmp[7] = tmp[15] = product[47];
+  tmp[16] = tmp[17] = tmp[18] = tmp[19] = tmp[20] = tmp[21] = tmp[22] =
+      tmp[23] = 0;
+  carry += mg_uecc_vli_add(result, result, tmp, num_words_secp192r1);
+
+  while (carry || mg_uecc_vli_cmp_unsafe(curve_secp192r1.p, result,
+                                         num_words_secp192r1) != 1) {
+    carry -=
+        mg_uecc_vli_sub(result, result, curve_secp192r1.p, num_words_secp192r1);
+  }
+}
+#elif MG_UECC_WORD_SIZE == 4
+static void vli_mmod_fast_secp192r1(uint32_t *result, uint32_t *product) {
+  uint32_t tmp[num_words_secp192r1];
+  int carry;
 
-  mg_iotest(mgr, ms);
-  now = mg_millis();
-  mg_timer_poll(&mgr->timers, now);
+  mg_uecc_vli_set(result, product, num_words_secp192r1);
 
-  for (c = mgr->conns; c != NULL; c = tmp) {
-    bool is_resp = c->is_resp;
-    tmp = c->next;
-    mg_call(c, MG_EV_POLL, &now);
-    if (is_resp && !c->is_resp) {
-      long n = 0;
-      mg_call(c, MG_EV_READ, &n);
-    }
-    MG_VERBOSE(("%lu %c%c %c%c%c%c%c", c->id, c->is_readable ? 'r' : '-',
-                c->is_writable ? 'w' : '-', c->is_tls ? 'T' : 't',
-                c->is_connecting ? 'C' : 'c', c->is_tls_hs ? 'H' : 'h',
-                c->is_resolving ? 'R' : 'r', c->is_closing ? 'C' : 'c'));
-    if (c->is_resolving || c->is_closing) {
-      // Do nothing
-    } else if (c->is_listening && c->is_udp == 0) {
-      if (c->is_readable) accept_conn(mgr, c);
-    } else if (c->is_connecting) {
-      if (c->is_readable || c->is_writable) connect_conn(c);
-    } else if (c->is_tls_hs) {
-      if ((c->is_readable || c->is_writable)) mg_tls_handshake(c);
-    } else {
-      if (c->is_readable) read_conn(c);
-      if (c->is_writable) write_conn(c);
-    }
+  mg_uecc_vli_set(tmp, &product[6], num_words_secp192r1);
+  carry = mg_uecc_vli_add(result, result, tmp, num_words_secp192r1);
 
-    if (c->is_draining && c->send.len == 0) c->is_closing = 1;
-    if (c->is_closing) close_conn(c);
+  tmp[0] = tmp[1] = 0;
+  tmp[2] = product[6];
+  tmp[3] = product[7];
+  tmp[4] = product[8];
+  tmp[5] = product[9];
+  carry += mg_uecc_vli_add(result, result, tmp, num_words_secp192r1);
+
+  tmp[0] = tmp[2] = product[10];
+  tmp[1] = tmp[3] = product[11];
+  tmp[4] = tmp[5] = 0;
+  carry += mg_uecc_vli_add(result, result, tmp, num_words_secp192r1);
+
+  while (carry || mg_uecc_vli_cmp_unsafe(curve_secp192r1.p, result,
+                                         num_words_secp192r1) != 1) {
+    carry -=
+        mg_uecc_vli_sub(result, result, curve_secp192r1.p, num_words_secp192r1);
+  }
+}
+#else
+static void vli_mmod_fast_secp192r1(uint64_t *result, uint64_t *product) {
+  uint64_t tmp[num_words_secp192r1];
+  int carry;
+
+  mg_uecc_vli_set(result, product, num_words_secp192r1);
+
+  mg_uecc_vli_set(tmp, &product[3], num_words_secp192r1);
+  carry = (int) mg_uecc_vli_add(result, result, tmp, num_words_secp192r1);
+
+  tmp[0] = 0;
+  tmp[1] = product[3];
+  tmp[2] = product[4];
+  carry += mg_uecc_vli_add(result, result, tmp, num_words_secp192r1);
+
+  tmp[0] = tmp[1] = product[5];
+  tmp[2] = 0;
+  carry += mg_uecc_vli_add(result, result, tmp, num_words_secp192r1);
+
+  while (carry || mg_uecc_vli_cmp_unsafe(curve_secp192r1.p, result,
+                                         num_words_secp192r1) != 1) {
+    carry -=
+        mg_uecc_vli_sub(result, result, curve_secp192r1.p, num_words_secp192r1);
   }
 }
+#endif /* MG_UECC_WORD_SIZE */
+#endif /* (MG_UECC_OPTIMIZATION_LEVEL > 0) */
+
+#endif /* MG_UECC_SUPPORTS_secp192r1 */
+
+#if MG_UECC_SUPPORTS_secp224r1
+
+#if MG_UECC_SUPPORT_COMPRESSED_POINT
+static void mod_sqrt_secp224r1(mg_uecc_word_t *a, MG_UECC_Curve curve);
+#endif
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0)
+static void vli_mmod_fast_secp224r1(mg_uecc_word_t *result,
+                                    mg_uecc_word_t *product);
 #endif
 
-#ifdef MG_ENABLE_LINES
-#line 1 "src/ssi.c"
+static const struct MG_UECC_Curve_t curve_secp224r1 = {
+    num_words_secp224r1,
+    num_bytes_secp224r1,
+    224, /* num_n_bits */
+    {BYTES_TO_WORDS_8(01, 00, 00, 00, 00, 00, 00, 00),
+     BYTES_TO_WORDS_8(00, 00, 00, 00, FF, FF, FF, FF),
+     BYTES_TO_WORDS_8(FF, FF, FF, FF, FF, FF, FF, FF),
+     BYTES_TO_WORDS_4(FF, FF, FF, FF)},
+    {BYTES_TO_WORDS_8(3D, 2A, 5C, 5C, 45, 29, DD, 13),
+     BYTES_TO_WORDS_8(3E, F0, B8, E0, A2, 16, FF, FF),
+     BYTES_TO_WORDS_8(FF, FF, FF, FF, FF, FF, FF, FF),
+     BYTES_TO_WORDS_4(FF, FF, FF, FF)},
+    {BYTES_TO_WORDS_8(21, 1D, 5C, 11, D6, 80, 32, 34),
+     BYTES_TO_WORDS_8(22, 11, C2, 56, D3, C1, 03, 4A),
+     BYTES_TO_WORDS_8(B9, 90, 13, 32, 7F, BF, B4, 6B),
+     BYTES_TO_WORDS_4(BD, 0C, 0E, B7),
+
+     BYTES_TO_WORDS_8(34, 7E, 00, 85, 99, 81, D5, 44),
+     BYTES_TO_WORDS_8(64, 47, 07, 5A, A0, 75, 43, CD),
+     BYTES_TO_WORDS_8(E6, DF, 22, 4C, FB, 23, F7, B5),
+     BYTES_TO_WORDS_4(88, 63, 37, BD)},
+    {BYTES_TO_WORDS_8(B4, FF, 55, 23, 43, 39, 0B, 27),
+     BYTES_TO_WORDS_8(BA, D8, BF, D7, B7, B0, 44, 50),
+     BYTES_TO_WORDS_8(56, 32, 41, F5, AB, B3, 04, 0C),
+     BYTES_TO_WORDS_4(85, 0A, 05, B4)},
+    &double_jacobian_default,
+#if MG_UECC_SUPPORT_COMPRESSED_POINT
+    &mod_sqrt_secp224r1,
 #endif
+    &x_side_default,
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0)
+    &vli_mmod_fast_secp224r1
+#endif
+};
+
+MG_UECC_Curve mg_uecc_secp224r1(void) {
+  return &curve_secp224r1;
+}
+
+#if MG_UECC_SUPPORT_COMPRESSED_POINT
+/* Routine 3.2.4 RS;  from http://www.nsa.gov/ia/_files/nist-routines.pdf */
+static void mod_sqrt_secp224r1_rs(mg_uecc_word_t *d1, mg_uecc_word_t *e1,
+                                  mg_uecc_word_t *f1, const mg_uecc_word_t *d0,
+                                  const mg_uecc_word_t *e0,
+                                  const mg_uecc_word_t *f0) {
+  mg_uecc_word_t t[num_words_secp224r1];
+
+  mg_uecc_vli_modSquare_fast(t, d0, &curve_secp224r1);    /* t <-- d0 ^ 2 */
+  mg_uecc_vli_modMult_fast(e1, d0, e0, &curve_secp224r1); /* e1 <-- d0 * e0 */
+  mg_uecc_vli_modAdd(d1, t, f0, curve_secp224r1.p,
+                     num_words_secp224r1); /* d1 <-- t  + f0 */
+  mg_uecc_vli_modAdd(e1, e1, e1, curve_secp224r1.p,
+                     num_words_secp224r1);               /* e1 <-- e1 + e1 */
+  mg_uecc_vli_modMult_fast(f1, t, f0, &curve_secp224r1); /* f1 <-- t  * f0 */
+  mg_uecc_vli_modAdd(f1, f1, f1, curve_secp224r1.p,
+                     num_words_secp224r1); /* f1 <-- f1 + f1 */
+  mg_uecc_vli_modAdd(f1, f1, f1, curve_secp224r1.p,
+                     num_words_secp224r1); /* f1 <-- f1 + f1 */
+}
+
+/* Routine 3.2.5 RSS;  from http://www.nsa.gov/ia/_files/nist-routines.pdf */
+static void mod_sqrt_secp224r1_rss(mg_uecc_word_t *d1, mg_uecc_word_t *e1,
+                                   mg_uecc_word_t *f1, const mg_uecc_word_t *d0,
+                                   const mg_uecc_word_t *e0,
+                                   const mg_uecc_word_t *f0,
+                                   const bitcount_t j) {
+  bitcount_t i;
+
+  mg_uecc_vli_set(d1, d0, num_words_secp224r1); /* d1 <-- d0 */
+  mg_uecc_vli_set(e1, e0, num_words_secp224r1); /* e1 <-- e0 */
+  mg_uecc_vli_set(f1, f0, num_words_secp224r1); /* f1 <-- f0 */
+  for (i = 1; i <= j; i++) {
+    mod_sqrt_secp224r1_rs(d1, e1, f1, d1, e1, f1); /* RS (d1,e1,f1,d1,e1,f1) */
+  }
+}
+
+/* Routine 3.2.6 RM;  from http://www.nsa.gov/ia/_files/nist-routines.pdf */
+static void mod_sqrt_secp224r1_rm(mg_uecc_word_t *d2, mg_uecc_word_t *e2,
+                                  mg_uecc_word_t *f2, const mg_uecc_word_t *c,
+                                  const mg_uecc_word_t *d0,
+                                  const mg_uecc_word_t *e0,
+                                  const mg_uecc_word_t *d1,
+                                  const mg_uecc_word_t *e1) {
+  mg_uecc_word_t t1[num_words_secp224r1];
+  mg_uecc_word_t t2[num_words_secp224r1];
+
+  mg_uecc_vli_modMult_fast(t1, e0, e1, &curve_secp224r1); /* t1 <-- e0 * e1 */
+  mg_uecc_vli_modMult_fast(t1, t1, c, &curve_secp224r1);  /* t1 <-- t1 * c */
+  /* t1 <-- p  - t1 */
+  mg_uecc_vli_modSub(t1, curve_secp224r1.p, t1, curve_secp224r1.p,
+                     num_words_secp224r1);
+  mg_uecc_vli_modMult_fast(t2, d0, d1, &curve_secp224r1); /* t2 <-- d0 * d1 */
+  mg_uecc_vli_modAdd(t2, t2, t1, curve_secp224r1.p,
+                     num_words_secp224r1);                /* t2 <-- t2 + t1 */
+  mg_uecc_vli_modMult_fast(t1, d0, e1, &curve_secp224r1); /* t1 <-- d0 * e1 */
+  mg_uecc_vli_modMult_fast(e2, d1, e0, &curve_secp224r1); /* e2 <-- d1 * e0 */
+  mg_uecc_vli_modAdd(e2, e2, t1, curve_secp224r1.p,
+                     num_words_secp224r1);               /* e2 <-- e2 + t1 */
+  mg_uecc_vli_modSquare_fast(f2, e2, &curve_secp224r1);  /* f2 <-- e2^2 */
+  mg_uecc_vli_modMult_fast(f2, f2, c, &curve_secp224r1); /* f2 <-- f2 * c */
+  /* f2 <-- p  - f2 */
+  mg_uecc_vli_modSub(f2, curve_secp224r1.p, f2, curve_secp224r1.p,
+                     num_words_secp224r1);
+  mg_uecc_vli_set(d2, t2, num_words_secp224r1); /* d2 <-- t2 */
+}
+
+/* Routine 3.2.7 RP;  from http://www.nsa.gov/ia/_files/nist-routines.pdf */
+static void mod_sqrt_secp224r1_rp(mg_uecc_word_t *d1, mg_uecc_word_t *e1,
+                                  mg_uecc_word_t *f1, const mg_uecc_word_t *c,
+                                  const mg_uecc_word_t *r) {
+  wordcount_t i;
+  wordcount_t pow2i = 1;
+  mg_uecc_word_t d0[num_words_secp224r1];
+  mg_uecc_word_t e0[num_words_secp224r1] = {1}; /* e0 <-- 1 */
+  mg_uecc_word_t f0[num_words_secp224r1];
+
+  mg_uecc_vli_set(d0, r, num_words_secp224r1); /* d0 <-- r */
+  /* f0 <-- p  - c */
+  mg_uecc_vli_modSub(f0, curve_secp224r1.p, c, curve_secp224r1.p,
+                     num_words_secp224r1);
+  for (i = 0; i <= 6; i++) {
+    mod_sqrt_secp224r1_rss(d1, e1, f1, d0, e0, f0,
+                           pow2i); /* RSS (d1,e1,f1,d0,e0,f0,2^i) */
+    mod_sqrt_secp224r1_rm(d1, e1, f1, c, d1, e1, d0,
+                          e0); /* RM (d1,e1,f1,c,d1,e1,d0,e0) */
+    mg_uecc_vli_set(d0, d1, num_words_secp224r1); /* d0 <-- d1 */
+    mg_uecc_vli_set(e0, e1, num_words_secp224r1); /* e0 <-- e1 */
+    mg_uecc_vli_set(f0, f1, num_words_secp224r1); /* f0 <-- f1 */
+    pow2i *= 2;
+  }
+}
 
+/* Compute a = sqrt(a) (mod curve_p). */
+/* Routine 3.2.8 mp_mod_sqrt_224; from
+ * http://www.nsa.gov/ia/_files/nist-routines.pdf */
+static void mod_sqrt_secp224r1(mg_uecc_word_t *a, MG_UECC_Curve curve) {
+  (void) curve;
+  bitcount_t i;
+  mg_uecc_word_t e1[num_words_secp224r1];
+  mg_uecc_word_t f1[num_words_secp224r1];
+  mg_uecc_word_t d0[num_words_secp224r1];
+  mg_uecc_word_t e0[num_words_secp224r1];
+  mg_uecc_word_t f0[num_words_secp224r1];
+  mg_uecc_word_t d1[num_words_secp224r1];
+
+  /* s = a; using constant instead of random value */
+  mod_sqrt_secp224r1_rp(d0, e0, f0, a, a); /* RP (d0, e0, f0, c, s) */
+  mod_sqrt_secp224r1_rs(d1, e1, f1, d0, e0,
+                        f0); /* RS (d1, e1, f1, d0, e0, f0) */
+  for (i = 1; i <= 95; i++) {
+    mg_uecc_vli_set(d0, d1, num_words_secp224r1); /* d0 <-- d1 */
+    mg_uecc_vli_set(e0, e1, num_words_secp224r1); /* e0 <-- e1 */
+    mg_uecc_vli_set(f0, f1, num_words_secp224r1); /* f0 <-- f1 */
+    mod_sqrt_secp224r1_rs(d1, e1, f1, d0, e0,
+                          f0); /* RS (d1, e1, f1, d0, e0, f0) */
+    if (mg_uecc_vli_isZero(d1, num_words_secp224r1)) { /* if d1 == 0 */
+      break;
+    }
+  }
+  mg_uecc_vli_modInv(f1, e0, curve_secp224r1.p,
+                     num_words_secp224r1);               /* f1 <-- 1 / e0 */
+  mg_uecc_vli_modMult_fast(a, d0, f1, &curve_secp224r1); /* a  <-- d0 / e0 */
+}
+#endif /* MG_UECC_SUPPORT_COMPRESSED_POINT */
+
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0)
+/* Computes result = product % curve_p
+   from http://www.nsa.gov/ia/_files/nist-routines.pdf */
+#if MG_UECC_WORD_SIZE == 1
+static void vli_mmod_fast_secp224r1(uint8_t *result, uint8_t *product) {
+  uint8_t tmp[num_words_secp224r1];
+  int8_t carry;
+
+  /* t */
+  mg_uecc_vli_set(result, product, num_words_secp224r1);
+
+  /* s1 */
+  tmp[0] = tmp[1] = tmp[2] = tmp[3] = 0;
+  tmp[4] = tmp[5] = tmp[6] = tmp[7] = 0;
+  tmp[8] = tmp[9] = tmp[10] = tmp[11] = 0;
+  tmp[12] = product[28];
+  tmp[13] = product[29];
+  tmp[14] = product[30];
+  tmp[15] = product[31];
+  tmp[16] = product[32];
+  tmp[17] = product[33];
+  tmp[18] = product[34];
+  tmp[19] = product[35];
+  tmp[20] = product[36];
+  tmp[21] = product[37];
+  tmp[22] = product[38];
+  tmp[23] = product[39];
+  tmp[24] = product[40];
+  tmp[25] = product[41];
+  tmp[26] = product[42];
+  tmp[27] = product[43];
+  carry = mg_uecc_vli_add(result, result, tmp, num_words_secp224r1);
+
+  /* s2 */
+  tmp[12] = product[44];
+  tmp[13] = product[45];
+  tmp[14] = product[46];
+  tmp[15] = product[47];
+  tmp[16] = product[48];
+  tmp[17] = product[49];
+  tmp[18] = product[50];
+  tmp[19] = product[51];
+  tmp[20] = product[52];
+  tmp[21] = product[53];
+  tmp[22] = product[54];
+  tmp[23] = product[55];
+  tmp[24] = tmp[25] = tmp[26] = tmp[27] = 0;
+  carry += mg_uecc_vli_add(result, result, tmp, num_words_secp224r1);
+
+  /* d1 */
+  tmp[0] = product[28];
+  tmp[1] = product[29];
+  tmp[2] = product[30];
+  tmp[3] = product[31];
+  tmp[4] = product[32];
+  tmp[5] = product[33];
+  tmp[6] = product[34];
+  tmp[7] = product[35];
+  tmp[8] = product[36];
+  tmp[9] = product[37];
+  tmp[10] = product[38];
+  tmp[11] = product[39];
+  tmp[12] = product[40];
+  tmp[13] = product[41];
+  tmp[14] = product[42];
+  tmp[15] = product[43];
+  tmp[16] = product[44];
+  tmp[17] = product[45];
+  tmp[18] = product[46];
+  tmp[19] = product[47];
+  tmp[20] = product[48];
+  tmp[21] = product[49];
+  tmp[22] = product[50];
+  tmp[23] = product[51];
+  tmp[24] = product[52];
+  tmp[25] = product[53];
+  tmp[26] = product[54];
+  tmp[27] = product[55];
+  carry -= mg_uecc_vli_sub(result, result, tmp, num_words_secp224r1);
+
+  /* d2 */
+  tmp[0] = product[44];
+  tmp[1] = product[45];
+  tmp[2] = product[46];
+  tmp[3] = product[47];
+  tmp[4] = product[48];
+  tmp[5] = product[49];
+  tmp[6] = product[50];
+  tmp[7] = product[51];
+  tmp[8] = product[52];
+  tmp[9] = product[53];
+  tmp[10] = product[54];
+  tmp[11] = product[55];
+  tmp[12] = tmp[13] = tmp[14] = tmp[15] = 0;
+  tmp[16] = tmp[17] = tmp[18] = tmp[19] = 0;
+  tmp[20] = tmp[21] = tmp[22] = tmp[23] = 0;
+  tmp[24] = tmp[25] = tmp[26] = tmp[27] = 0;
+  carry -= mg_uecc_vli_sub(result, result, tmp, num_words_secp224r1);
+
+  if (carry < 0) {
+    do {
+      carry += mg_uecc_vli_add(result, result, curve_secp224r1.p,
+                               num_words_secp224r1);
+    } while (carry < 0);
+  } else {
+    while (carry || mg_uecc_vli_cmp_unsafe(curve_secp224r1.p, result,
+                                           num_words_secp224r1) != 1) {
+      carry -= mg_uecc_vli_sub(result, result, curve_secp224r1.p,
+                               num_words_secp224r1);
+    }
+  }
+}
+#elif MG_UECC_WORD_SIZE == 4
+static void vli_mmod_fast_secp224r1(uint32_t *result, uint32_t *product) {
+  uint32_t tmp[num_words_secp224r1];
+  int carry;
+
+  /* t */
+  mg_uecc_vli_set(result, product, num_words_secp224r1);
+
+  /* s1 */
+  tmp[0] = tmp[1] = tmp[2] = 0;
+  tmp[3] = product[7];
+  tmp[4] = product[8];
+  tmp[5] = product[9];
+  tmp[6] = product[10];
+  carry = mg_uecc_vli_add(result, result, tmp, num_words_secp224r1);
+
+  /* s2 */
+  tmp[3] = product[11];
+  tmp[4] = product[12];
+  tmp[5] = product[13];
+  tmp[6] = 0;
+  carry += mg_uecc_vli_add(result, result, tmp, num_words_secp224r1);
+
+  /* d1 */
+  tmp[0] = product[7];
+  tmp[1] = product[8];
+  tmp[2] = product[9];
+  tmp[3] = product[10];
+  tmp[4] = product[11];
+  tmp[5] = product[12];
+  tmp[6] = product[13];
+  carry -= mg_uecc_vli_sub(result, result, tmp, num_words_secp224r1);
+
+  /* d2 */
+  tmp[0] = product[11];
+  tmp[1] = product[12];
+  tmp[2] = product[13];
+  tmp[3] = tmp[4] = tmp[5] = tmp[6] = 0;
+  carry -= mg_uecc_vli_sub(result, result, tmp, num_words_secp224r1);
+
+  if (carry < 0) {
+    do {
+      carry += mg_uecc_vli_add(result, result, curve_secp224r1.p,
+                               num_words_secp224r1);
+    } while (carry < 0);
+  } else {
+    while (carry || mg_uecc_vli_cmp_unsafe(curve_secp224r1.p, result,
+                                           num_words_secp224r1) != 1) {
+      carry -= mg_uecc_vli_sub(result, result, curve_secp224r1.p,
+                               num_words_secp224r1);
+    }
+  }
+}
+#else
+static void vli_mmod_fast_secp224r1(uint64_t *result, uint64_t *product) {
+  uint64_t tmp[num_words_secp224r1];
+  int carry = 0;
+
+  /* t */
+  mg_uecc_vli_set(result, product, num_words_secp224r1);
+  result[num_words_secp224r1 - 1] &= 0xffffffff;
+
+  /* s1 */
+  tmp[0] = 0;
+  tmp[1] = product[3] & 0xffffffff00000000ull;
+  tmp[2] = product[4];
+  tmp[3] = product[5] & 0xffffffff;
+  mg_uecc_vli_add(result, result, tmp, num_words_secp224r1);
+
+  /* s2 */
+  tmp[1] = product[5] & 0xffffffff00000000ull;
+  tmp[2] = product[6];
+  tmp[3] = 0;
+  mg_uecc_vli_add(result, result, tmp, num_words_secp224r1);
+
+  /* d1 */
+  tmp[0] = (product[3] >> 32) | (product[4] << 32);
+  tmp[1] = (product[4] >> 32) | (product[5] << 32);
+  tmp[2] = (product[5] >> 32) | (product[6] << 32);
+  tmp[3] = product[6] >> 32;
+  carry -= mg_uecc_vli_sub(result, result, tmp, num_words_secp224r1);
+
+  /* d2 */
+  tmp[0] = (product[5] >> 32) | (product[6] << 32);
+  tmp[1] = product[6] >> 32;
+  tmp[2] = tmp[3] = 0;
+  carry -= mg_uecc_vli_sub(result, result, tmp, num_words_secp224r1);
+
+  if (carry < 0) {
+    do {
+      carry += mg_uecc_vli_add(result, result, curve_secp224r1.p,
+                               num_words_secp224r1);
+    } while (carry < 0);
+  } else {
+    while (mg_uecc_vli_cmp_unsafe(curve_secp224r1.p, result,
+                                  num_words_secp224r1) != 1) {
+      mg_uecc_vli_sub(result, result, curve_secp224r1.p, num_words_secp224r1);
+    }
+  }
+}
+#endif /* MG_UECC_WORD_SIZE */
+#endif /* (MG_UECC_OPTIMIZATION_LEVEL > 0) */
 
+#endif /* MG_UECC_SUPPORTS_secp224r1 */
 
+#if MG_UECC_SUPPORTS_secp256r1
 
-#ifndef MG_MAX_SSI_DEPTH
-#define MG_MAX_SSI_DEPTH 5
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0)
+static void vli_mmod_fast_secp256r1(mg_uecc_word_t *result,
+                                    mg_uecc_word_t *product);
 #endif
 
-#ifndef MG_SSI_BUFSIZ
-#define MG_SSI_BUFSIZ 1024
+static const struct MG_UECC_Curve_t curve_secp256r1 = {
+    num_words_secp256r1,
+    num_bytes_secp256r1,
+    256, /* num_n_bits */
+    {BYTES_TO_WORDS_8(FF, FF, FF, FF, FF, FF, FF, FF),
+     BYTES_TO_WORDS_8(FF, FF, FF, FF, 00, 00, 00, 00),
+     BYTES_TO_WORDS_8(00, 00, 00, 00, 00, 00, 00, 00),
+     BYTES_TO_WORDS_8(01, 00, 00, 00, FF, FF, FF, FF)},
+    {BYTES_TO_WORDS_8(51, 25, 63, FC, C2, CA, B9, F3),
+     BYTES_TO_WORDS_8(84, 9E, 17, A7, AD, FA, E6, BC),
+     BYTES_TO_WORDS_8(FF, FF, FF, FF, FF, FF, FF, FF),
+     BYTES_TO_WORDS_8(00, 00, 00, 00, FF, FF, FF, FF)},
+    {BYTES_TO_WORDS_8(96, C2, 98, D8, 45, 39, A1, F4),
+     BYTES_TO_WORDS_8(A0, 33, EB, 2D, 81, 7D, 03, 77),
+     BYTES_TO_WORDS_8(F2, 40, A4, 63, E5, E6, BC, F8),
+     BYTES_TO_WORDS_8(47, 42, 2C, E1, F2, D1, 17, 6B),
+
+     BYTES_TO_WORDS_8(F5, 51, BF, 37, 68, 40, B6, CB),
+     BYTES_TO_WORDS_8(CE, 5E, 31, 6B, 57, 33, CE, 2B),
+     BYTES_TO_WORDS_8(16, 9E, 0F, 7C, 4A, EB, E7, 8E),
+     BYTES_TO_WORDS_8(9B, 7F, 1A, FE, E2, 42, E3, 4F)},
+    {BYTES_TO_WORDS_8(4B, 60, D2, 27, 3E, 3C, CE, 3B),
+     BYTES_TO_WORDS_8(F6, B0, 53, CC, B0, 06, 1D, 65),
+     BYTES_TO_WORDS_8(BC, 86, 98, 76, 55, BD, EB, B3),
+     BYTES_TO_WORDS_8(E7, 93, 3A, AA, D8, 35, C6, 5A)},
+    &double_jacobian_default,
+#if MG_UECC_SUPPORT_COMPRESSED_POINT
+    &mod_sqrt_default,
+#endif
+    &x_side_default,
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0)
+    &vli_mmod_fast_secp256r1
 #endif
+};
 
-#if MG_ENABLE_SSI
-static char *mg_ssi(const char *path, const char *root, int depth) {
-  struct mg_iobuf b = {NULL, 0, 0, MG_IO_SIZE};
-  FILE *fp = fopen(path, "rb");
-  if (fp != NULL) {
-    char buf[MG_SSI_BUFSIZ], arg[sizeof(buf)];
-    int ch, intag = 0;
-    size_t len = 0;
-    buf[0] = arg[0] = '\0';
-    while ((ch = fgetc(fp)) != EOF) {
-      if (intag && ch == '>' && buf[len - 1] == '-' && buf[len - 2] == '-') {
-        buf[len++] = (char) (ch & 0xff);
-        buf[len] = '\0';
-        if (sscanf(buf, "<!--#include file=\"%[^\"]", arg)) {
-          char tmp[MG_PATH_MAX + MG_SSI_BUFSIZ + 10],
-              *p = (char *) path + strlen(path), *data;
-          while (p > path && p[-1] != MG_DIRSEP && p[-1] != '/') p--;
-          mg_snprintf(tmp, sizeof(tmp), "%.*s%s", (int) (p - path), path, arg);
-          if (depth < MG_MAX_SSI_DEPTH &&
-              (data = mg_ssi(tmp, root, depth + 1)) != NULL) {
-            mg_iobuf_add(&b, b.len, data, strlen(data));
-            free(data);
-          } else {
-            MG_ERROR(("%s: file=%s error or too deep", path, arg));
-          }
-        } else if (sscanf(buf, "<!--#include virtual=\"%[^\"]", arg)) {
-          char tmp[MG_PATH_MAX + MG_SSI_BUFSIZ + 10], *data;
-          mg_snprintf(tmp, sizeof(tmp), "%s%s", root, arg);
-          if (depth < MG_MAX_SSI_DEPTH &&
-              (data = mg_ssi(tmp, root, depth + 1)) != NULL) {
-            mg_iobuf_add(&b, b.len, data, strlen(data));
-            free(data);
-          } else {
-            MG_ERROR(("%s: virtual=%s error or too deep", path, arg));
-          }
-        } else {
-          // Unknown SSI tag
-          MG_ERROR(("Unknown SSI tag: %.*s", (int) len, buf));
-          mg_iobuf_add(&b, b.len, buf, len);
-        }
-        intag = 0;
-        len = 0;
-      } else if (ch == '<') {
-        intag = 1;
-        if (len > 0) mg_iobuf_add(&b, b.len, buf, len);
-        len = 0;
-        buf[len++] = (char) (ch & 0xff);
-      } else if (intag) {
-        if (len == 5 && strncmp(buf, "<!--#", 5) != 0) {
-          intag = 0;
-        } else if (len >= sizeof(buf) - 2) {
-          MG_ERROR(("%s: SSI tag is too large", path));
-          len = 0;
-        }
-        buf[len++] = (char) (ch & 0xff);
-      } else {
-        buf[len++] = (char) (ch & 0xff);
-        if (len >= sizeof(buf)) {
-          mg_iobuf_add(&b, b.len, buf, len);
-          len = 0;
-        }
-      }
+MG_UECC_Curve mg_uecc_secp256r1(void) {
+  return &curve_secp256r1;
+}
+
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0 && !asm_mmod_fast_secp256r1)
+/* Computes result = product % curve_p
+   from http://www.nsa.gov/ia/_files/nist-routines.pdf */
+#if MG_UECC_WORD_SIZE == 1
+static void vli_mmod_fast_secp256r1(uint8_t *result, uint8_t *product) {
+  uint8_t tmp[num_words_secp256r1];
+  int8_t carry;
+
+  /* t */
+  mg_uecc_vli_set(result, product, num_words_secp256r1);
+
+  /* s1 */
+  tmp[0] = tmp[1] = tmp[2] = tmp[3] = 0;
+  tmp[4] = tmp[5] = tmp[6] = tmp[7] = 0;
+  tmp[8] = tmp[9] = tmp[10] = tmp[11] = 0;
+  tmp[12] = product[44];
+  tmp[13] = product[45];
+  tmp[14] = product[46];
+  tmp[15] = product[47];
+  tmp[16] = product[48];
+  tmp[17] = product[49];
+  tmp[18] = product[50];
+  tmp[19] = product[51];
+  tmp[20] = product[52];
+  tmp[21] = product[53];
+  tmp[22] = product[54];
+  tmp[23] = product[55];
+  tmp[24] = product[56];
+  tmp[25] = product[57];
+  tmp[26] = product[58];
+  tmp[27] = product[59];
+  tmp[28] = product[60];
+  tmp[29] = product[61];
+  tmp[30] = product[62];
+  tmp[31] = product[63];
+  carry = mg_uecc_vli_add(tmp, tmp, tmp, num_words_secp256r1);
+  carry += mg_uecc_vli_add(result, result, tmp, num_words_secp256r1);
+
+  /* s2 */
+  tmp[12] = product[48];
+  tmp[13] = product[49];
+  tmp[14] = product[50];
+  tmp[15] = product[51];
+  tmp[16] = product[52];
+  tmp[17] = product[53];
+  tmp[18] = product[54];
+  tmp[19] = product[55];
+  tmp[20] = product[56];
+  tmp[21] = product[57];
+  tmp[22] = product[58];
+  tmp[23] = product[59];
+  tmp[24] = product[60];
+  tmp[25] = product[61];
+  tmp[26] = product[62];
+  tmp[27] = product[63];
+  tmp[28] = tmp[29] = tmp[30] = tmp[31] = 0;
+  carry += mg_uecc_vli_add(tmp, tmp, tmp, num_words_secp256r1);
+  carry += mg_uecc_vli_add(result, result, tmp, num_words_secp256r1);
+
+  /* s3 */
+  tmp[0] = product[32];
+  tmp[1] = product[33];
+  tmp[2] = product[34];
+  tmp[3] = product[35];
+  tmp[4] = product[36];
+  tmp[5] = product[37];
+  tmp[6] = product[38];
+  tmp[7] = product[39];
+  tmp[8] = product[40];
+  tmp[9] = product[41];
+  tmp[10] = product[42];
+  tmp[11] = product[43];
+  tmp[12] = tmp[13] = tmp[14] = tmp[15] = 0;
+  tmp[16] = tmp[17] = tmp[18] = tmp[19] = 0;
+  tmp[20] = tmp[21] = tmp[22] = tmp[23] = 0;
+  tmp[24] = product[56];
+  tmp[25] = product[57];
+  tmp[26] = product[58];
+  tmp[27] = product[59];
+  tmp[28] = product[60];
+  tmp[29] = product[61];
+  tmp[30] = product[62];
+  tmp[31] = product[63];
+  carry += mg_uecc_vli_add(result, result, tmp, num_words_secp256r1);
+
+  /* s4 */
+  tmp[0] = product[36];
+  tmp[1] = product[37];
+  tmp[2] = product[38];
+  tmp[3] = product[39];
+  tmp[4] = product[40];
+  tmp[5] = product[41];
+  tmp[6] = product[42];
+  tmp[7] = product[43];
+  tmp[8] = product[44];
+  tmp[9] = product[45];
+  tmp[10] = product[46];
+  tmp[11] = product[47];
+  tmp[12] = product[52];
+  tmp[13] = product[53];
+  tmp[14] = product[54];
+  tmp[15] = product[55];
+  tmp[16] = product[56];
+  tmp[17] = product[57];
+  tmp[18] = product[58];
+  tmp[19] = product[59];
+  tmp[20] = product[60];
+  tmp[21] = product[61];
+  tmp[22] = product[62];
+  tmp[23] = product[63];
+  tmp[24] = product[52];
+  tmp[25] = product[53];
+  tmp[26] = product[54];
+  tmp[27] = product[55];
+  tmp[28] = product[32];
+  tmp[29] = product[33];
+  tmp[30] = product[34];
+  tmp[31] = product[35];
+  carry += mg_uecc_vli_add(result, result, tmp, num_words_secp256r1);
+
+  /* d1 */
+  tmp[0] = product[44];
+  tmp[1] = product[45];
+  tmp[2] = product[46];
+  tmp[3] = product[47];
+  tmp[4] = product[48];
+  tmp[5] = product[49];
+  tmp[6] = product[50];
+  tmp[7] = product[51];
+  tmp[8] = product[52];
+  tmp[9] = product[53];
+  tmp[10] = product[54];
+  tmp[11] = product[55];
+  tmp[12] = tmp[13] = tmp[14] = tmp[15] = 0;
+  tmp[16] = tmp[17] = tmp[18] = tmp[19] = 0;
+  tmp[20] = tmp[21] = tmp[22] = tmp[23] = 0;
+  tmp[24] = product[32];
+  tmp[25] = product[33];
+  tmp[26] = product[34];
+  tmp[27] = product[35];
+  tmp[28] = product[40];
+  tmp[29] = product[41];
+  tmp[30] = product[42];
+  tmp[31] = product[43];
+  carry -= mg_uecc_vli_sub(result, result, tmp, num_words_secp256r1);
+
+  /* d2 */
+  tmp[0] = product[48];
+  tmp[1] = product[49];
+  tmp[2] = product[50];
+  tmp[3] = product[51];
+  tmp[4] = product[52];
+  tmp[5] = product[53];
+  tmp[6] = product[54];
+  tmp[7] = product[55];
+  tmp[8] = product[56];
+  tmp[9] = product[57];
+  tmp[10] = product[58];
+  tmp[11] = product[59];
+  tmp[12] = product[60];
+  tmp[13] = product[61];
+  tmp[14] = product[62];
+  tmp[15] = product[63];
+  tmp[16] = tmp[17] = tmp[18] = tmp[19] = 0;
+  tmp[20] = tmp[21] = tmp[22] = tmp[23] = 0;
+  tmp[24] = product[36];
+  tmp[25] = product[37];
+  tmp[26] = product[38];
+  tmp[27] = product[39];
+  tmp[28] = product[44];
+  tmp[29] = product[45];
+  tmp[30] = product[46];
+  tmp[31] = product[47];
+  carry -= mg_uecc_vli_sub(result, result, tmp, num_words_secp256r1);
+
+  /* d3 */
+  tmp[0] = product[52];
+  tmp[1] = product[53];
+  tmp[2] = product[54];
+  tmp[3] = product[55];
+  tmp[4] = product[56];
+  tmp[5] = product[57];
+  tmp[6] = product[58];
+  tmp[7] = product[59];
+  tmp[8] = product[60];
+  tmp[9] = product[61];
+  tmp[10] = product[62];
+  tmp[11] = product[63];
+  tmp[12] = product[32];
+  tmp[13] = product[33];
+  tmp[14] = product[34];
+  tmp[15] = product[35];
+  tmp[16] = product[36];
+  tmp[17] = product[37];
+  tmp[18] = product[38];
+  tmp[19] = product[39];
+  tmp[20] = product[40];
+  tmp[21] = product[41];
+  tmp[22] = product[42];
+  tmp[23] = product[43];
+  tmp[24] = tmp[25] = tmp[26] = tmp[27] = 0;
+  tmp[28] = product[48];
+  tmp[29] = product[49];
+  tmp[30] = product[50];
+  tmp[31] = product[51];
+  carry -= mg_uecc_vli_sub(result, result, tmp, num_words_secp256r1);
+
+  /* d4 */
+  tmp[0] = product[56];
+  tmp[1] = product[57];
+  tmp[2] = product[58];
+  tmp[3] = product[59];
+  tmp[4] = product[60];
+  tmp[5] = product[61];
+  tmp[6] = product[62];
+  tmp[7] = product[63];
+  tmp[8] = tmp[9] = tmp[10] = tmp[11] = 0;
+  tmp[12] = product[36];
+  tmp[13] = product[37];
+  tmp[14] = product[38];
+  tmp[15] = product[39];
+  tmp[16] = product[40];
+  tmp[17] = product[41];
+  tmp[18] = product[42];
+  tmp[19] = product[43];
+  tmp[20] = product[44];
+  tmp[21] = product[45];
+  tmp[22] = product[46];
+  tmp[23] = product[47];
+  tmp[24] = tmp[25] = tmp[26] = tmp[27] = 0;
+  tmp[28] = product[52];
+  tmp[29] = product[53];
+  tmp[30] = product[54];
+  tmp[31] = product[55];
+  carry -= mg_uecc_vli_sub(result, result, tmp, num_words_secp256r1);
+
+  if (carry < 0) {
+    do {
+      carry += mg_uecc_vli_add(result, result, curve_secp256r1.p,
+                               num_words_secp256r1);
+    } while (carry < 0);
+  } else {
+    while (carry || mg_uecc_vli_cmp_unsafe(curve_secp256r1.p, result,
+                                           num_words_secp256r1) != 1) {
+      carry -= mg_uecc_vli_sub(result, result, curve_secp256r1.p,
+                               num_words_secp256r1);
     }
-    if (len > 0) mg_iobuf_add(&b, b.len, buf, len);
-    if (b.len > 0) mg_iobuf_add(&b, b.len, "", 1);  // nul-terminate
-    fclose(fp);
   }
-  (void) depth;
-  (void) root;
-  return (char *) b.buf;
 }
-
-void mg_http_serve_ssi(struct mg_connection *c, const char *root,
-                       const char *fullpath) {
-  const char *headers = "Content-Type: text/html; charset=utf-8\r\n";
-  char *data = mg_ssi(fullpath, root, 0);
-  mg_http_reply(c, 200, headers, "%s", data == NULL ? "" : data);
-  free(data);
+#elif MG_UECC_WORD_SIZE == 4
+static void vli_mmod_fast_secp256r1(uint32_t *result, uint32_t *product) {
+  uint32_t tmp[num_words_secp256r1];
+  int carry;
+
+  /* t */
+  mg_uecc_vli_set(result, product, num_words_secp256r1);
+
+  /* s1 */
+  tmp[0] = tmp[1] = tmp[2] = 0;
+  tmp[3] = product[11];
+  tmp[4] = product[12];
+  tmp[5] = product[13];
+  tmp[6] = product[14];
+  tmp[7] = product[15];
+  carry = (int) mg_uecc_vli_add(tmp, tmp, tmp, num_words_secp256r1);
+  carry += (int) mg_uecc_vli_add(result, result, tmp, num_words_secp256r1);
+
+  /* s2 */
+  tmp[3] = product[12];
+  tmp[4] = product[13];
+  tmp[5] = product[14];
+  tmp[6] = product[15];
+  tmp[7] = 0;
+  carry += (int) mg_uecc_vli_add(tmp, tmp, tmp, num_words_secp256r1);
+  carry += (int) mg_uecc_vli_add(result, result, tmp, num_words_secp256r1);
+
+  /* s3 */
+  tmp[0] = product[8];
+  tmp[1] = product[9];
+  tmp[2] = product[10];
+  tmp[3] = tmp[4] = tmp[5] = 0;
+  tmp[6] = product[14];
+  tmp[7] = product[15];
+  carry += (int) mg_uecc_vli_add(result, result, tmp, num_words_secp256r1);
+
+  /* s4 */
+  tmp[0] = product[9];
+  tmp[1] = product[10];
+  tmp[2] = product[11];
+  tmp[3] = product[13];
+  tmp[4] = product[14];
+  tmp[5] = product[15];
+  tmp[6] = product[13];
+  tmp[7] = product[8];
+  carry += (int) mg_uecc_vli_add(result, result, tmp, num_words_secp256r1);
+
+  /* d1 */
+  tmp[0] = product[11];
+  tmp[1] = product[12];
+  tmp[2] = product[13];
+  tmp[3] = tmp[4] = tmp[5] = 0;
+  tmp[6] = product[8];
+  tmp[7] = product[10];
+  carry -= (int) mg_uecc_vli_sub(result, result, tmp, num_words_secp256r1);
+
+  /* d2 */
+  tmp[0] = product[12];
+  tmp[1] = product[13];
+  tmp[2] = product[14];
+  tmp[3] = product[15];
+  tmp[4] = tmp[5] = 0;
+  tmp[6] = product[9];
+  tmp[7] = product[11];
+  carry -= (int) mg_uecc_vli_sub(result, result, tmp, num_words_secp256r1);
+
+  /* d3 */
+  tmp[0] = product[13];
+  tmp[1] = product[14];
+  tmp[2] = product[15];
+  tmp[3] = product[8];
+  tmp[4] = product[9];
+  tmp[5] = product[10];
+  tmp[6] = 0;
+  tmp[7] = product[12];
+  carry -= (int) mg_uecc_vli_sub(result, result, tmp, num_words_secp256r1);
+
+  /* d4 */
+  tmp[0] = product[14];
+  tmp[1] = product[15];
+  tmp[2] = 0;
+  tmp[3] = product[9];
+  tmp[4] = product[10];
+  tmp[5] = product[11];
+  tmp[6] = 0;
+  tmp[7] = product[13];
+  carry -= (int) mg_uecc_vli_sub(result, result, tmp, num_words_secp256r1);
+
+  if (carry < 0) {
+    do {
+      carry += (int) mg_uecc_vli_add(result, result, curve_secp256r1.p,
+                                     num_words_secp256r1);
+    } while (carry < 0);
+  } else {
+    while (carry || mg_uecc_vli_cmp_unsafe(curve_secp256r1.p, result,
+                                           num_words_secp256r1) != 1) {
+      carry -= (int) mg_uecc_vli_sub(result, result, curve_secp256r1.p,
+                                     num_words_secp256r1);
+    }
+  }
 }
 #else
-void mg_http_serve_ssi(struct mg_connection *c, const char *root,
-                       const char *fullpath) {
-  mg_http_reply(c, 501, NULL, "SSI not enabled");
-  (void) root, (void) fullpath;
+static void vli_mmod_fast_secp256r1(uint64_t *result, uint64_t *product) {
+  uint64_t tmp[num_words_secp256r1];
+  int carry;
+
+  /* t */
+  mg_uecc_vli_set(result, product, num_words_secp256r1);
+
+  /* s1 */
+  tmp[0] = 0;
+  tmp[1] = product[5] & 0xffffffff00000000U;
+  tmp[2] = product[6];
+  tmp[3] = product[7];
+  carry = (int) mg_uecc_vli_add(tmp, tmp, tmp, num_words_secp256r1);
+  carry += (int) mg_uecc_vli_add(result, result, tmp, num_words_secp256r1);
+
+  /* s2 */
+  tmp[1] = product[6] << 32;
+  tmp[2] = (product[6] >> 32) | (product[7] << 32);
+  tmp[3] = product[7] >> 32;
+  carry += (int) mg_uecc_vli_add(tmp, tmp, tmp, num_words_secp256r1);
+  carry += (int) mg_uecc_vli_add(result, result, tmp, num_words_secp256r1);
+
+  /* s3 */
+  tmp[0] = product[4];
+  tmp[1] = product[5] & 0xffffffff;
+  tmp[2] = 0;
+  tmp[3] = product[7];
+  carry += (int) mg_uecc_vli_add(result, result, tmp, num_words_secp256r1);
+
+  /* s4 */
+  tmp[0] = (product[4] >> 32) | (product[5] << 32);
+  tmp[1] = (product[5] >> 32) | (product[6] & 0xffffffff00000000U);
+  tmp[2] = product[7];
+  tmp[3] = (product[6] >> 32) | (product[4] << 32);
+  carry += (int) mg_uecc_vli_add(result, result, tmp, num_words_secp256r1);
+
+  /* d1 */
+  tmp[0] = (product[5] >> 32) | (product[6] << 32);
+  tmp[1] = (product[6] >> 32);
+  tmp[2] = 0;
+  tmp[3] = (product[4] & 0xffffffff) | (product[5] << 32);
+  carry -= (int) mg_uecc_vli_sub(result, result, tmp, num_words_secp256r1);
+
+  /* d2 */
+  tmp[0] = product[6];
+  tmp[1] = product[7];
+  tmp[2] = 0;
+  tmp[3] = (product[4] >> 32) | (product[5] & 0xffffffff00000000);
+  carry -= (int) mg_uecc_vli_sub(result, result, tmp, num_words_secp256r1);
+
+  /* d3 */
+  tmp[0] = (product[6] >> 32) | (product[7] << 32);
+  tmp[1] = (product[7] >> 32) | (product[4] << 32);
+  tmp[2] = (product[4] >> 32) | (product[5] << 32);
+  tmp[3] = (product[6] << 32);
+  carry -= (int) mg_uecc_vli_sub(result, result, tmp, num_words_secp256r1);
+
+  /* d4 */
+  tmp[0] = product[7];
+  tmp[1] = product[4] & 0xffffffff00000000U;
+  tmp[2] = product[5];
+  tmp[3] = product[6] & 0xffffffff00000000U;
+  carry -= (int) mg_uecc_vli_sub(result, result, tmp, num_words_secp256r1);
+
+  if (carry < 0) {
+    do {
+      carry += (int) mg_uecc_vli_add(result, result, curve_secp256r1.p,
+                                     num_words_secp256r1);
+    } while (carry < 0);
+  } else {
+    while (carry || mg_uecc_vli_cmp_unsafe(curve_secp256r1.p, result,
+                                           num_words_secp256r1) != 1) {
+      carry -= (int) mg_uecc_vli_sub(result, result, curve_secp256r1.p,
+                                     num_words_secp256r1);
+    }
+  }
 }
-#endif
+#endif /* MG_UECC_WORD_SIZE */
+#endif /* (MG_UECC_OPTIMIZATION_LEVEL > 0 && !asm_mmod_fast_secp256r1) */
 
-#ifdef MG_ENABLE_LINES
-#line 1 "src/str.c"
+#endif /* MG_UECC_SUPPORTS_secp256r1 */
+
+#if MG_UECC_SUPPORTS_secp256k1
+
+static void double_jacobian_secp256k1(mg_uecc_word_t *X1, mg_uecc_word_t *Y1,
+                                      mg_uecc_word_t *Z1, MG_UECC_Curve curve);
+static void x_side_secp256k1(mg_uecc_word_t *result, const mg_uecc_word_t *x,
+                             MG_UECC_Curve curve);
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0)
+static void vli_mmod_fast_secp256k1(mg_uecc_word_t *result,
+                                    mg_uecc_word_t *product);
 #endif
 
+static const struct MG_UECC_Curve_t curve_secp256k1 = {
+    num_words_secp256k1,
+    num_bytes_secp256k1,
+    256, /* num_n_bits */
+    {BYTES_TO_WORDS_8(2F, FC, FF, FF, FE, FF, FF, FF),
+     BYTES_TO_WORDS_8(FF, FF, FF, FF, FF, FF, FF, FF),
+     BYTES_TO_WORDS_8(FF, FF, FF, FF, FF, FF, FF, FF),
+     BYTES_TO_WORDS_8(FF, FF, FF, FF, FF, FF, FF, FF)},
+    {BYTES_TO_WORDS_8(41, 41, 36, D0, 8C, 5E, D2, BF),
+     BYTES_TO_WORDS_8(3B, A0, 48, AF, E6, DC, AE, BA),
+     BYTES_TO_WORDS_8(FE, FF, FF, FF, FF, FF, FF, FF),
+     BYTES_TO_WORDS_8(FF, FF, FF, FF, FF, FF, FF, FF)},
+    {BYTES_TO_WORDS_8(98, 17, F8, 16, 5B, 81, F2, 59),
+     BYTES_TO_WORDS_8(D9, 28, CE, 2D, DB, FC, 9B, 02),
+     BYTES_TO_WORDS_8(07, 0B, 87, CE, 95, 62, A0, 55),
+     BYTES_TO_WORDS_8(AC, BB, DC, F9, 7E, 66, BE, 79),
+
+     BYTES_TO_WORDS_8(B8, D4, 10, FB, 8F, D0, 47, 9C),
+     BYTES_TO_WORDS_8(19, 54, 85, A6, 48, B4, 17, FD),
+     BYTES_TO_WORDS_8(A8, 08, 11, 0E, FC, FB, A4, 5D),
+     BYTES_TO_WORDS_8(65, C4, A3, 26, 77, DA, 3A, 48)},
+    {BYTES_TO_WORDS_8(07, 00, 00, 00, 00, 00, 00, 00),
+     BYTES_TO_WORDS_8(00, 00, 00, 00, 00, 00, 00, 00),
+     BYTES_TO_WORDS_8(00, 00, 00, 00, 00, 00, 00, 00),
+     BYTES_TO_WORDS_8(00, 00, 00, 00, 00, 00, 00, 00)},
+    &double_jacobian_secp256k1,
+#if MG_UECC_SUPPORT_COMPRESSED_POINT
+    &mod_sqrt_default,
+#endif
+    &x_side_secp256k1,
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0)
+    &vli_mmod_fast_secp256k1
+#endif
+};
 
-struct mg_str mg_str_s(const char *s) {
-  struct mg_str str = {s, s == NULL ? 0 : strlen(s)};
-  return str;
+MG_UECC_Curve mg_uecc_secp256k1(void) {
+  return &curve_secp256k1;
 }
 
-struct mg_str mg_str_n(const char *s, size_t n) {
-  struct mg_str str = {s, n};
-  return str;
-}
+/* Double in place */
+static void double_jacobian_secp256k1(mg_uecc_word_t *X1, mg_uecc_word_t *Y1,
+                                      mg_uecc_word_t *Z1, MG_UECC_Curve curve) {
+  /* t1 = X, t2 = Y, t3 = Z */
+  mg_uecc_word_t t4[num_words_secp256k1];
+  mg_uecc_word_t t5[num_words_secp256k1];
 
-int mg_lower(const char *s) {
-  int c = *s;
-  if (c >= 'A' && c <= 'Z') c += 'a' - 'A';
-  return c;
-}
+  if (mg_uecc_vli_isZero(Z1, num_words_secp256k1)) {
+    return;
+  }
 
-int mg_ncasecmp(const char *s1, const char *s2, size_t len) {
-  int diff = 0;
-  if (len > 0) do {
-      diff = mg_lower(s1++) - mg_lower(s2++);
-    } while (diff == 0 && s1[-1] != '\0' && --len > 0);
-  return diff;
+  mg_uecc_vli_modSquare_fast(t5, Y1, curve);   /* t5 = y1^2 */
+  mg_uecc_vli_modMult_fast(t4, X1, t5, curve); /* t4 = x1*y1^2 = A */
+  mg_uecc_vli_modSquare_fast(X1, X1, curve);   /* t1 = x1^2 */
+  mg_uecc_vli_modSquare_fast(t5, t5, curve);   /* t5 = y1^4 */
+  mg_uecc_vli_modMult_fast(Z1, Y1, Z1, curve); /* t3 = y1*z1 = z3 */
+
+  mg_uecc_vli_modAdd(Y1, X1, X1, curve->p,
+                     num_words_secp256k1); /* t2 = 2*x1^2 */
+  mg_uecc_vli_modAdd(Y1, Y1, X1, curve->p,
+                     num_words_secp256k1); /* t2 = 3*x1^2 */
+  if (mg_uecc_vli_testBit(Y1, 0)) {
+    mg_uecc_word_t carry =
+        mg_uecc_vli_add(Y1, Y1, curve->p, num_words_secp256k1);
+    mg_uecc_vli_rshift1(Y1, num_words_secp256k1);
+    Y1[num_words_secp256k1 - 1] |= carry << (MG_UECC_WORD_BITS - 1);
+  } else {
+    mg_uecc_vli_rshift1(Y1, num_words_secp256k1);
+  }
+  /* t2 = 3/2*(x1^2) = B */
+
+  mg_uecc_vli_modSquare_fast(X1, Y1, curve); /* t1 = B^2 */
+  mg_uecc_vli_modSub(X1, X1, t4, curve->p,
+                     num_words_secp256k1); /* t1 = B^2 - A */
+  mg_uecc_vli_modSub(X1, X1, t4, curve->p,
+                     num_words_secp256k1); /* t1 = B^2 - 2A = x3 */
+
+  mg_uecc_vli_modSub(t4, t4, X1, curve->p,
+                     num_words_secp256k1);     /* t4 = A - x3 */
+  mg_uecc_vli_modMult_fast(Y1, Y1, t4, curve); /* t2 = B * (A - x3) */
+  mg_uecc_vli_modSub(Y1, Y1, t5, curve->p,
+                     num_words_secp256k1); /* t2 = B * (A - x3) - y1^4 = y3 */
+}
+
+/* Computes result = x^3 + b. result must not overlap x. */
+static void x_side_secp256k1(mg_uecc_word_t *result, const mg_uecc_word_t *x,
+                             MG_UECC_Curve curve) {
+  mg_uecc_vli_modSquare_fast(result, x, curve);       /* r = x^2 */
+  mg_uecc_vli_modMult_fast(result, result, x, curve); /* r = x^3 */
+  mg_uecc_vli_modAdd(result, result, curve->b, curve->p,
+                     num_words_secp256k1); /* r = x^3 + b */
+}
+
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0 && !asm_mmod_fast_secp256k1)
+static void omega_mult_secp256k1(mg_uecc_word_t *result,
+                                 const mg_uecc_word_t *right);
+static void vli_mmod_fast_secp256k1(mg_uecc_word_t *result,
+                                    mg_uecc_word_t *product) {
+  mg_uecc_word_t tmp[2 * num_words_secp256k1];
+  mg_uecc_word_t carry;
+
+  mg_uecc_vli_clear(tmp, num_words_secp256k1);
+  mg_uecc_vli_clear(tmp + num_words_secp256k1, num_words_secp256k1);
+
+  omega_mult_secp256k1(tmp,
+                       product + num_words_secp256k1); /* (Rq, q) = q * c */
+
+  carry = mg_uecc_vli_add(result, product, tmp,
+                          num_words_secp256k1); /* (C, r) = r + q       */
+  mg_uecc_vli_clear(product, num_words_secp256k1);
+  omega_mult_secp256k1(product, tmp + num_words_secp256k1); /* Rq*c */
+  carry += mg_uecc_vli_add(result, result, product,
+                           num_words_secp256k1); /* (C1, r) = r + Rq*c */
+
+  while (carry > 0) {
+    --carry;
+    mg_uecc_vli_sub(result, result, curve_secp256k1.p, num_words_secp256k1);
+  }
+  if (mg_uecc_vli_cmp_unsafe(result, curve_secp256k1.p, num_words_secp256k1) >
+      0) {
+    mg_uecc_vli_sub(result, result, curve_secp256k1.p, num_words_secp256k1);
+  }
 }
 
-int mg_casecmp(const char *s1, const char *s2) {
-  return mg_ncasecmp(s1, s2, (size_t) ~0);
+#if MG_UECC_WORD_SIZE == 1
+static void omega_mult_secp256k1(uint8_t *result, const uint8_t *right) {
+  /* Multiply by (2^32 + 2^9 + 2^8 + 2^7 + 2^6 + 2^4 + 1). */
+  mg_uecc_word_t r0 = 0;
+  mg_uecc_word_t r1 = 0;
+  mg_uecc_word_t r2 = 0;
+  wordcount_t k;
+
+  /* Multiply by (2^9 + 2^8 + 2^7 + 2^6 + 2^4 + 1). */
+  muladd(0xD1, right[0], &r0, &r1, &r2);
+  result[0] = r0;
+  r0 = r1;
+  r1 = r2;
+  /* r2 is still 0 */
+
+  for (k = 1; k < num_words_secp256k1; ++k) {
+    muladd(0x03, right[k - 1], &r0, &r1, &r2);
+    muladd(0xD1, right[k], &r0, &r1, &r2);
+    result[k] = r0;
+    r0 = r1;
+    r1 = r2;
+    r2 = 0;
+  }
+  muladd(0x03, right[num_words_secp256k1 - 1], &r0, &r1, &r2);
+  result[num_words_secp256k1] = r0;
+  result[num_words_secp256k1 + 1] = r1;
+  /* add the 2^32 multiple */
+  result[4 + num_words_secp256k1] =
+      mg_uecc_vli_add(result + 4, result + 4, right, num_words_secp256k1);
+}
+#elif MG_UECC_WORD_SIZE == 4
+static void omega_mult_secp256k1(uint32_t *result, const uint32_t *right) {
+  /* Multiply by (2^9 + 2^8 + 2^7 + 2^6 + 2^4 + 1). */
+  uint32_t carry = 0;
+  wordcount_t k;
+
+  for (k = 0; k < num_words_secp256k1; ++k) {
+    uint64_t p = (uint64_t) 0x3D1 * right[k] + carry;
+    result[k] = (uint32_t) p;
+    carry = p >> 32;
+  }
+  result[num_words_secp256k1] = carry;
+  /* add the 2^32 multiple */
+  result[1 + num_words_secp256k1] =
+      mg_uecc_vli_add(result + 1, result + 1, right, num_words_secp256k1);
 }
-
-int mg_vcmp(const struct mg_str *s1, const char *s2) {
-  size_t n2 = strlen(s2), n1 = s1->len;
-  int r = strncmp(s1->ptr, s2, (n1 < n2) ? n1 : n2);
-  if (r == 0) return (int) (n1 - n2);
-  return r;
+#else
+static void omega_mult_secp256k1(uint64_t *result, const uint64_t *right) {
+  mg_uecc_word_t r0 = 0;
+  mg_uecc_word_t r1 = 0;
+  mg_uecc_word_t r2 = 0;
+  wordcount_t k;
+
+  /* Multiply by (2^32 + 2^9 + 2^8 + 2^7 + 2^6 + 2^4 + 1). */
+  for (k = 0; k < num_words_secp256k1; ++k) {
+    muladd(0x1000003D1ull, right[k], &r0, &r1, &r2);
+    result[k] = r0;
+    r0 = r1;
+    r1 = r2;
+    r2 = 0;
+  }
+  result[num_words_secp256k1] = r0;
 }
+#endif /* MG_UECC_WORD_SIZE */
+#endif /* (MG_UECC_OPTIMIZATION_LEVEL > 0 &&  && !asm_mmod_fast_secp256k1) */
 
-int mg_vcasecmp(const struct mg_str *str1, const char *str2) {
-  size_t n2 = strlen(str2), n1 = str1->len;
-  int r = mg_ncasecmp(str1->ptr, str2, (n1 < n2) ? n1 : n2);
-  if (r == 0) return (int) (n1 - n2);
-  return r;
+#endif /* MG_UECC_SUPPORTS_secp256k1 */
+
+#endif /* _UECC_CURVE_SPECIFIC_H_ */
+
+/* Returns 1 if 'point' is the point at infinity, 0 otherwise. */
+#define EccPoint_isZero(point, curve) \
+  mg_uecc_vli_isZero((point), (wordcount_t) ((curve)->num_words * 2))
+
+/* Point multiplication algorithm using Montgomery's ladder with co-Z
+coordinates. From http://eprint.iacr.org/2011/338.pdf
+*/
+
+/* Modify (x1, y1) => (x1 * z^2, y1 * z^3) */
+static void apply_z(mg_uecc_word_t *X1, mg_uecc_word_t *Y1,
+                    const mg_uecc_word_t *const Z, MG_UECC_Curve curve) {
+  mg_uecc_word_t t1[MG_UECC_MAX_WORDS];
+
+  mg_uecc_vli_modSquare_fast(t1, Z, curve);    /* z^2 */
+  mg_uecc_vli_modMult_fast(X1, X1, t1, curve); /* x1 * z^2 */
+  mg_uecc_vli_modMult_fast(t1, t1, Z, curve);  /* z^3 */
+  mg_uecc_vli_modMult_fast(Y1, Y1, t1, curve); /* y1 * z^3 */
 }
 
-struct mg_str mg_strdup(const struct mg_str s) {
-  struct mg_str r = {NULL, 0};
-  if (s.len > 0 && s.ptr != NULL) {
-    char *sc = (char *) calloc(1, s.len + 1);
-    if (sc != NULL) {
-      memcpy(sc, s.ptr, s.len);
-      sc[s.len] = '\0';
-      r.ptr = sc;
-      r.len = s.len;
-    }
+/* P = (x1, y1) => 2P, (x2, y2) => P' */
+static void XYcZ_initial_double(mg_uecc_word_t *X1, mg_uecc_word_t *Y1,
+                                mg_uecc_word_t *X2, mg_uecc_word_t *Y2,
+                                const mg_uecc_word_t *const initial_Z,
+                                MG_UECC_Curve curve) {
+  mg_uecc_word_t z[MG_UECC_MAX_WORDS];
+  wordcount_t num_words = curve->num_words;
+  if (initial_Z) {
+    mg_uecc_vli_set(z, initial_Z, num_words);
+  } else {
+    mg_uecc_vli_clear(z, num_words);
+    z[0] = 1;
   }
-  return r;
-}
 
-int mg_strcmp(const struct mg_str str1, const struct mg_str str2) {
-  size_t i = 0;
-  while (i < str1.len && i < str2.len) {
-    int c1 = str1.ptr[i];
-    int c2 = str2.ptr[i];
-    if (c1 < c2) return -1;
-    if (c1 > c2) return 1;
-    i++;
+  mg_uecc_vli_set(X2, X1, num_words);
+  mg_uecc_vli_set(Y2, Y1, num_words);
+
+  apply_z(X1, Y1, z, curve);
+  curve->double_jacobian(X1, Y1, z, curve);
+  apply_z(X2, Y2, z, curve);
+}
+
+/* Input P = (x1, y1, Z), Q = (x2, y2, Z)
+   Output P' = (x1', y1', Z3), P + Q = (x3, y3, Z3)
+   or P => P', Q => P + Q
+*/
+static void XYcZ_add(mg_uecc_word_t *X1, mg_uecc_word_t *Y1, mg_uecc_word_t *X2,
+                     mg_uecc_word_t *Y2, MG_UECC_Curve curve) {
+  /* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */
+  mg_uecc_word_t t5[MG_UECC_MAX_WORDS] = {0};
+  wordcount_t num_words = curve->num_words;
+
+  mg_uecc_vli_modSub(t5, X2, X1, curve->p, num_words); /* t5 = x2 - x1 */
+  mg_uecc_vli_modSquare_fast(t5, t5, curve);   /* t5 = (x2 - x1)^2 = A */
+  mg_uecc_vli_modMult_fast(X1, X1, t5, curve); /* t1 = x1*A = B */
+  mg_uecc_vli_modMult_fast(X2, X2, t5, curve); /* t3 = x2*A = C */
+  mg_uecc_vli_modSub(Y2, Y2, Y1, curve->p, num_words); /* t4 = y2 - y1 */
+  mg_uecc_vli_modSquare_fast(t5, Y2, curve); /* t5 = (y2 - y1)^2 = D */
+
+  mg_uecc_vli_modSub(t5, t5, X1, curve->p, num_words); /* t5 = D - B */
+  mg_uecc_vli_modSub(t5, t5, X2, curve->p, num_words); /* t5 = D - B - C = x3 */
+  mg_uecc_vli_modSub(X2, X2, X1, curve->p, num_words); /* t3 = C - B */
+  mg_uecc_vli_modMult_fast(Y1, Y1, X2, curve);         /* t2 = y1*(C - B) */
+  mg_uecc_vli_modSub(X2, X1, t5, curve->p, num_words); /* t3 = B - x3 */
+  mg_uecc_vli_modMult_fast(Y2, Y2, X2, curve); /* t4 = (y2 - y1)*(B - x3) */
+  mg_uecc_vli_modSub(Y2, Y2, Y1, curve->p, num_words); /* t4 = y3 */
+
+  mg_uecc_vli_set(X2, t5, num_words);
+}
+
+/* Input P = (x1, y1, Z), Q = (x2, y2, Z)
+   Output P + Q = (x3, y3, Z3), P - Q = (x3', y3', Z3)
+   or P => P - Q, Q => P + Q
+*/
+static void XYcZ_addC(mg_uecc_word_t *X1, mg_uecc_word_t *Y1,
+                      mg_uecc_word_t *X2, mg_uecc_word_t *Y2,
+                      MG_UECC_Curve curve) {
+  /* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */
+  mg_uecc_word_t t5[MG_UECC_MAX_WORDS] = {0};
+  mg_uecc_word_t t6[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t t7[MG_UECC_MAX_WORDS];
+  wordcount_t num_words = curve->num_words;
+
+  mg_uecc_vli_modSub(t5, X2, X1, curve->p, num_words); /* t5 = x2 - x1 */
+  mg_uecc_vli_modSquare_fast(t5, t5, curve);   /* t5 = (x2 - x1)^2 = A */
+  mg_uecc_vli_modMult_fast(X1, X1, t5, curve); /* t1 = x1*A = B */
+  mg_uecc_vli_modMult_fast(X2, X2, t5, curve); /* t3 = x2*A = C */
+  mg_uecc_vli_modAdd(t5, Y2, Y1, curve->p, num_words); /* t5 = y2 + y1 */
+  mg_uecc_vli_modSub(Y2, Y2, Y1, curve->p, num_words); /* t4 = y2 - y1 */
+
+  mg_uecc_vli_modSub(t6, X2, X1, curve->p, num_words); /* t6 = C - B */
+  mg_uecc_vli_modMult_fast(Y1, Y1, t6, curve); /* t2 = y1 * (C - B) = E */
+  mg_uecc_vli_modAdd(t6, X1, X2, curve->p, num_words); /* t6 = B + C */
+  mg_uecc_vli_modSquare_fast(X2, Y2, curve); /* t3 = (y2 - y1)^2 = D */
+  mg_uecc_vli_modSub(X2, X2, t6, curve->p,
+                     num_words); /* t3 = D - (B + C) = x3 */
+
+  mg_uecc_vli_modSub(t7, X1, X2, curve->p, num_words); /* t7 = B - x3 */
+  mg_uecc_vli_modMult_fast(Y2, Y2, t7, curve); /* t4 = (y2 - y1)*(B - x3) */
+  mg_uecc_vli_modSub(Y2, Y2, Y1, curve->p,
+                     num_words); /* t4 = (y2 - y1)*(B - x3) - E = y3 */
+
+  mg_uecc_vli_modSquare_fast(t7, t5, curve); /* t7 = (y2 + y1)^2 = F */
+  mg_uecc_vli_modSub(t7, t7, t6, curve->p,
+                     num_words); /* t7 = F - (B + C) = x3' */
+  mg_uecc_vli_modSub(t6, t7, X1, curve->p, num_words); /* t6 = x3' - B */
+  mg_uecc_vli_modMult_fast(t6, t6, t5, curve); /* t6 = (y2+y1)*(x3' - B) */
+  mg_uecc_vli_modSub(Y1, t6, Y1, curve->p,
+                     num_words); /* t2 = (y2+y1)*(x3' - B) - E = y3' */
+
+  mg_uecc_vli_set(X1, t7, num_words);
+}
+
+/* result may overlap point. */
+static void EccPoint_mult(mg_uecc_word_t *result, const mg_uecc_word_t *point,
+                          const mg_uecc_word_t *scalar,
+                          const mg_uecc_word_t *initial_Z, bitcount_t num_bits,
+                          MG_UECC_Curve curve) {
+  /* R0 and R1 */
+  mg_uecc_word_t Rx[2][MG_UECC_MAX_WORDS];
+  mg_uecc_word_t Ry[2][MG_UECC_MAX_WORDS];
+  mg_uecc_word_t z[MG_UECC_MAX_WORDS];
+  bitcount_t i;
+  mg_uecc_word_t nb;
+  wordcount_t num_words = curve->num_words;
+
+  mg_uecc_vli_set(Rx[1], point, num_words);
+  mg_uecc_vli_set(Ry[1], point + num_words, num_words);
+
+  XYcZ_initial_double(Rx[1], Ry[1], Rx[0], Ry[0], initial_Z, curve);
+
+  for (i = num_bits - 2; i > 0; --i) {
+    nb = !mg_uecc_vli_testBit(scalar, i);
+    XYcZ_addC(Rx[1 - nb], Ry[1 - nb], Rx[nb], Ry[nb], curve);
+    XYcZ_add(Rx[nb], Ry[nb], Rx[1 - nb], Ry[1 - nb], curve);
+  }
+
+  nb = !mg_uecc_vli_testBit(scalar, 0);
+  XYcZ_addC(Rx[1 - nb], Ry[1 - nb], Rx[nb], Ry[nb], curve);
+
+  /* Find final 1/Z value. */
+  mg_uecc_vli_modSub(z, Rx[1], Rx[0], curve->p, num_words); /* X1 - X0 */
+  mg_uecc_vli_modMult_fast(z, z, Ry[1 - nb], curve);        /* Yb * (X1 - X0) */
+  mg_uecc_vli_modMult_fast(z, z, point, curve);  /* xP * Yb * (X1 - X0) */
+  mg_uecc_vli_modInv(z, z, curve->p, num_words); /* 1 / (xP * Yb * (X1 - X0)) */
+  /* yP / (xP * Yb * (X1 - X0)) */
+  mg_uecc_vli_modMult_fast(z, z, point + num_words, curve);
+  mg_uecc_vli_modMult_fast(z, z, Rx[1 - nb],
+                           curve); /* Xb * yP / (xP * Yb * (X1 - X0)) */
+  /* End 1/Z calculation */
+
+  XYcZ_add(Rx[nb], Ry[nb], Rx[1 - nb], Ry[1 - nb], curve);
+  apply_z(Rx[0], Ry[0], z, curve);
+
+  mg_uecc_vli_set(result, Rx[0], num_words);
+  mg_uecc_vli_set(result + num_words, Ry[0], num_words);
+}
+
+static mg_uecc_word_t regularize_k(const mg_uecc_word_t *const k,
+                                   mg_uecc_word_t *k0, mg_uecc_word_t *k1,
+                                   MG_UECC_Curve curve) {
+  wordcount_t num_n_words = BITS_TO_WORDS(curve->num_n_bits);
+  bitcount_t num_n_bits = curve->num_n_bits;
+  mg_uecc_word_t carry =
+      mg_uecc_vli_add(k0, k, curve->n, num_n_words) ||
+      (num_n_bits < ((bitcount_t) num_n_words * MG_UECC_WORD_SIZE * 8) &&
+       mg_uecc_vli_testBit(k0, num_n_bits));
+  mg_uecc_vli_add(k1, k0, curve->n, num_n_words);
+  return carry;
+}
+
+/* Generates a random integer in the range 0 < random < top.
+   Both random and top have num_words words. */
+MG_UECC_VLI_API int mg_uecc_generate_random_int(mg_uecc_word_t *random,
+                                                const mg_uecc_word_t *top,
+                                                wordcount_t num_words) {
+  mg_uecc_word_t mask = (mg_uecc_word_t) -1;
+  mg_uecc_word_t tries;
+  bitcount_t num_bits = mg_uecc_vli_numBits(top, num_words);
+
+  if (!g_rng_function) {
+    return 0;
+  }
+
+  for (tries = 0; tries < MG_UECC_RNG_MAX_TRIES; ++tries) {
+    if (!g_rng_function((uint8_t *) random,
+                        (unsigned int) (num_words * MG_UECC_WORD_SIZE))) {
+      return 0;
+    }
+    random[num_words - 1] &=
+        mask >> ((bitcount_t) (num_words * MG_UECC_WORD_SIZE * 8 - num_bits));
+    if (!mg_uecc_vli_isZero(random, num_words) &&
+        mg_uecc_vli_cmp(top, random, num_words) == 1) {
+      return 1;
+    }
   }
-  if (i < str1.len) return 1;
-  if (i < str2.len) return -1;
   return 0;
 }
 
-const char *mg_strstr(const struct mg_str haystack,
-                      const struct mg_str needle) {
-  size_t i;
-  if (needle.len > haystack.len) return NULL;
-  for (i = 0; i <= haystack.len - needle.len; i++) {
-    if (memcmp(haystack.ptr + i, needle.ptr, needle.len) == 0) {
-      return haystack.ptr + i;
+static mg_uecc_word_t EccPoint_compute_public_key(mg_uecc_word_t *result,
+                                                  mg_uecc_word_t *private_key,
+                                                  MG_UECC_Curve curve) {
+  mg_uecc_word_t tmp1[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t tmp2[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t *p2[2] = {tmp1, tmp2};
+  mg_uecc_word_t *initial_Z = 0;
+  mg_uecc_word_t carry;
+
+  /* Regularize the bitcount for the private key so that attackers cannot use a
+     side channel attack to learn the number of leading zeros. */
+  carry = regularize_k(private_key, tmp1, tmp2, curve);
+
+  /* If an RNG function was specified, try to get a random initial Z value to
+     improve protection against side-channel attacks. */
+  if (g_rng_function) {
+    if (!mg_uecc_generate_random_int(p2[carry], curve->p, curve->num_words)) {
+      return 0;
     }
+    initial_Z = p2[carry];
   }
-  return NULL;
+  EccPoint_mult(result, curve->G, p2[!carry], initial_Z,
+                (bitcount_t) (curve->num_n_bits + 1), curve);
+
+  if (EccPoint_isZero(result, curve)) {
+    return 0;
+  }
+  return 1;
 }
 
-static bool is_space(int c) {
-  return c == ' ' || c == '\r' || c == '\n' || c == '\t';
+#if MG_UECC_WORD_SIZE == 1
+
+MG_UECC_VLI_API void mg_uecc_vli_nativeToBytes(uint8_t *bytes, int num_bytes,
+                                               const uint8_t *native) {
+  wordcount_t i;
+  for (i = 0; i < num_bytes; ++i) {
+    bytes[i] = native[(num_bytes - 1) - i];
+  }
 }
 
-struct mg_str mg_strstrip(struct mg_str s) {
-  while (s.len > 0 && is_space((int) *s.ptr)) s.ptr++, s.len--;
-  while (s.len > 0 && is_space((int) *(s.ptr + s.len - 1))) s.len--;
-  return s;
+MG_UECC_VLI_API void mg_uecc_vli_bytesToNative(uint8_t *native,
+                                               const uint8_t *bytes,
+                                               int num_bytes) {
+  mg_uecc_vli_nativeToBytes(native, num_bytes, bytes);
 }
 
-bool mg_match(struct mg_str s, struct mg_str p, struct mg_str *caps) {
-  size_t i = 0, j = 0, ni = 0, nj = 0;
-  if (caps) caps->ptr = NULL, caps->len = 0;
-  while (i < p.len || j < s.len) {
-    if (i < p.len && j < s.len && (p.ptr[i] == '?' || s.ptr[j] == p.ptr[i])) {
-      if (caps == NULL) {
-      } else if (p.ptr[i] == '?') {
-        caps->ptr = &s.ptr[j], caps->len = 1;     // Finalize `?` cap
-        caps++, caps->ptr = NULL, caps->len = 0;  // Init next cap
-      } else if (caps->ptr != NULL && caps->len == 0) {
-        caps->len = (size_t) (&s.ptr[j] - caps->ptr);  // Finalize current cap
-        caps++, caps->len = 0, caps->ptr = NULL;       // Init next cap
-      }
-      i++, j++;
-    } else if (i < p.len && (p.ptr[i] == '*' || p.ptr[i] == '#')) {
-      if (caps && !caps->ptr) caps->len = 0, caps->ptr = &s.ptr[j];  // Init cap
-      ni = i++, nj = j + 1;
-    } else if (nj > 0 && nj <= s.len && (p.ptr[ni] == '#' || s.ptr[j] != '/')) {
-      i = ni, j = nj;
-      if (caps && caps->ptr == NULL && caps->len == 0) {
-        caps--, caps->len = 0;  // Restart previous cap
-      }
-    } else {
-      return false;
-    }
-  }
-  if (caps && caps->ptr && caps->len == 0) {
-    caps->len = (size_t) (&s.ptr[j] - caps->ptr);
+#else
+
+MG_UECC_VLI_API void mg_uecc_vli_nativeToBytes(uint8_t *bytes, int num_bytes,
+                                               const mg_uecc_word_t *native) {
+  int i;
+  for (i = 0; i < num_bytes; ++i) {
+    unsigned b = (unsigned) (num_bytes - 1 - i);
+    bytes[i] = (uint8_t) (native[b / MG_UECC_WORD_SIZE] >>
+                          (8 * (b % MG_UECC_WORD_SIZE)));
   }
-  return true;
 }
 
-bool mg_globmatch(const char *s1, size_t n1, const char *s2, size_t n2) {
-  return mg_match(mg_str_n(s2, n2), mg_str_n(s1, n1), NULL);
+MG_UECC_VLI_API void mg_uecc_vli_bytesToNative(mg_uecc_word_t *native,
+                                               const uint8_t *bytes,
+                                               int num_bytes) {
+  int i;
+  mg_uecc_vli_clear(native,
+                    (wordcount_t) ((num_bytes + (MG_UECC_WORD_SIZE - 1)) /
+                                   MG_UECC_WORD_SIZE));
+  for (i = 0; i < num_bytes; ++i) {
+    unsigned b = (unsigned) (num_bytes - 1 - i);
+    native[b / MG_UECC_WORD_SIZE] |= (mg_uecc_word_t) bytes[i]
+                                     << (8 * (b % MG_UECC_WORD_SIZE));
+  }
 }
 
-static size_t mg_nce(const char *s, size_t n, size_t ofs, size_t *koff,
-                     size_t *klen, size_t *voff, size_t *vlen, char delim) {
-  size_t kvlen, kl;
-  for (kvlen = 0; ofs + kvlen < n && s[ofs + kvlen] != delim;) kvlen++;
-  for (kl = 0; kl < kvlen && s[ofs + kl] != '=';) kl++;
-  if (koff != NULL) *koff = ofs;
-  if (klen != NULL) *klen = kl;
-  if (voff != NULL) *voff = kl < kvlen ? ofs + kl + 1 : 0;
-  if (vlen != NULL) *vlen = kl < kvlen ? kvlen - kl - 1 : 0;
-  ofs += kvlen + 1;
-  return ofs > n ? n : ofs;
+#endif /* MG_UECC_WORD_SIZE */
+
+int mg_uecc_make_key(uint8_t *public_key, uint8_t *private_key,
+                     MG_UECC_Curve curve) {
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN
+  mg_uecc_word_t *_private = (mg_uecc_word_t *) private_key;
+  mg_uecc_word_t *_public = (mg_uecc_word_t *) public_key;
+#else
+  mg_uecc_word_t _private[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t _public[MG_UECC_MAX_WORDS * 2];
+#endif
+  mg_uecc_word_t tries;
+
+  for (tries = 0; tries < MG_UECC_RNG_MAX_TRIES; ++tries) {
+    if (!mg_uecc_generate_random_int(_private, curve->n,
+                                     BITS_TO_WORDS(curve->num_n_bits))) {
+      return 0;
+    }
+
+    if (EccPoint_compute_public_key(_public, _private, curve)) {
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN == 0
+      mg_uecc_vli_nativeToBytes(private_key, BITS_TO_BYTES(curve->num_n_bits),
+                                _private);
+      mg_uecc_vli_nativeToBytes(public_key, curve->num_bytes, _public);
+      mg_uecc_vli_nativeToBytes(public_key + curve->num_bytes, curve->num_bytes,
+                                _public + curve->num_words);
+#endif
+      return 1;
+    }
+  }
+  return 0;
 }
 
-bool mg_split(struct mg_str *s, struct mg_str *k, struct mg_str *v, char sep) {
-  size_t koff = 0, klen = 0, voff = 0, vlen = 0, off = 0;
-  if (s->ptr == NULL || s->len == 0) return 0;
-  off = mg_nce(s->ptr, s->len, 0, &koff, &klen, &voff, &vlen, sep);
-  if (k != NULL) *k = mg_str_n(s->ptr + koff, klen);
-  if (v != NULL) *v = mg_str_n(s->ptr + voff, vlen);
-  *s = mg_str_n(s->ptr + off, s->len - off);
-  return off > 0;
+int mg_uecc_shared_secret(const uint8_t *public_key, const uint8_t *private_key,
+                          uint8_t *secret, MG_UECC_Curve curve) {
+  mg_uecc_word_t _public[MG_UECC_MAX_WORDS * 2];
+  mg_uecc_word_t _private[MG_UECC_MAX_WORDS];
+
+  mg_uecc_word_t tmp[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t *p2[2] = {_private, tmp};
+  mg_uecc_word_t *initial_Z = 0;
+  mg_uecc_word_t carry;
+  wordcount_t num_words = curve->num_words;
+  wordcount_t num_bytes = curve->num_bytes;
+
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN
+  bcopy((uint8_t *) _private, private_key, num_bytes);
+  bcopy((uint8_t *) _public, public_key, num_bytes * 2);
+#else
+  mg_uecc_vli_bytesToNative(_private, private_key,
+                            BITS_TO_BYTES(curve->num_n_bits));
+  mg_uecc_vli_bytesToNative(_public, public_key, num_bytes);
+  mg_uecc_vli_bytesToNative(_public + num_words, public_key + num_bytes,
+                            num_bytes);
+#endif
+
+  /* Regularize the bitcount for the private key so that attackers cannot use a
+     side channel attack to learn the number of leading zeros. */
+  carry = regularize_k(_private, _private, tmp, curve);
+
+  /* If an RNG function was specified, try to get a random initial Z value to
+     improve protection against side-channel attacks. */
+  if (g_rng_function) {
+    if (!mg_uecc_generate_random_int(p2[carry], curve->p, num_words)) {
+      return 0;
+    }
+    initial_Z = p2[carry];
+  }
+
+  EccPoint_mult(_public, _public, p2[!carry], initial_Z,
+                (bitcount_t) (curve->num_n_bits + 1), curve);
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN
+  bcopy((uint8_t *) secret, (uint8_t *) _public, num_bytes);
+#else
+  mg_uecc_vli_nativeToBytes(secret, num_bytes, _public);
+#endif
+  return !EccPoint_isZero(_public, curve);
 }
 
-bool mg_commalist(struct mg_str *s, struct mg_str *k, struct mg_str *v) {
-  return mg_split(s, k, v, ',');
+#if MG_UECC_SUPPORT_COMPRESSED_POINT
+void mg_uecc_compress(const uint8_t *public_key, uint8_t *compressed,
+                      MG_UECC_Curve curve) {
+  wordcount_t i;
+  for (i = 0; i < curve->num_bytes; ++i) {
+    compressed[i + 1] = public_key[i];
+  }
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN
+  compressed[0] = 2 + (public_key[curve->num_bytes] & 0x01);
+#else
+  compressed[0] = 2 + (public_key[curve->num_bytes * 2 - 1] & 0x01);
+#endif
 }
 
-char *mg_hex(const void *buf, size_t len, char *to) {
-  const unsigned char *p = (const unsigned char *) buf;
-  const char *hex = "0123456789abcdef";
-  size_t i = 0;
-  for (; len--; p++) {
-    to[i++] = hex[p[0] >> 4];
-    to[i++] = hex[p[0] & 0x0f];
+void mg_uecc_decompress(const uint8_t *compressed, uint8_t *public_key,
+                        MG_UECC_Curve curve) {
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN
+  mg_uecc_word_t *point = (mg_uecc_word_t *) public_key;
+#else
+  mg_uecc_word_t point[MG_UECC_MAX_WORDS * 2];
+#endif
+  mg_uecc_word_t *y = point + curve->num_words;
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN
+  bcopy(public_key, compressed + 1, curve->num_bytes);
+#else
+  mg_uecc_vli_bytesToNative(point, compressed + 1, curve->num_bytes);
+#endif
+  curve->x_side(y, point, curve);
+  curve->mod_sqrt(y, curve);
+
+  if ((uint8_t) (y[0] & 0x01) != (compressed[0] & 0x01)) {
+    mg_uecc_vli_sub(y, curve->p, y, curve->num_words);
   }
-  to[i] = '\0';
-  return to;
+
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN == 0
+  mg_uecc_vli_nativeToBytes(public_key, curve->num_bytes, point);
+  mg_uecc_vli_nativeToBytes(public_key + curve->num_bytes, curve->num_bytes, y);
+#endif
 }
+#endif /* MG_UECC_SUPPORT_COMPRESSED_POINT */
+
+MG_UECC_VLI_API int mg_uecc_valid_point(const mg_uecc_word_t *point,
+                                        MG_UECC_Curve curve) {
+  mg_uecc_word_t tmp1[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t tmp2[MG_UECC_MAX_WORDS];
+  wordcount_t num_words = curve->num_words;
+
+  /* The point at infinity is invalid. */
+  if (EccPoint_isZero(point, curve)) {
+    return 0;
+  }
 
-static unsigned char mg_unhex_nimble(unsigned char c) {
-  return (c >= '0' && c <= '9')   ? (unsigned char) (c - '0')
-         : (c >= 'A' && c <= 'F') ? (unsigned char) (c - '7')
-                                  : (unsigned char) (c - 'W');
+  /* x and y must be smaller than p. */
+  if (mg_uecc_vli_cmp_unsafe(curve->p, point, num_words) != 1 ||
+      mg_uecc_vli_cmp_unsafe(curve->p, point + num_words, num_words) != 1) {
+    return 0;
+  }
+
+  mg_uecc_vli_modSquare_fast(tmp1, point + num_words, curve);
+  curve->x_side(tmp2, point, curve); /* tmp2 = x^3 + ax + b */
+
+  /* Make sure that y^2 == x^3 + ax + b */
+  return (int) (mg_uecc_vli_equal(tmp1, tmp2, num_words));
 }
 
-unsigned long mg_unhexn(const char *s, size_t len) {
-  unsigned long i = 0, v = 0;
-  for (i = 0; i < len; i++) v <<= 4, v |= mg_unhex_nimble(((uint8_t *) s)[i]);
-  return v;
+int mg_uecc_valid_public_key(const uint8_t *public_key, MG_UECC_Curve curve) {
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN
+  mg_uecc_word_t *_public = (mg_uecc_word_t *) public_key;
+#else
+  mg_uecc_word_t _public[MG_UECC_MAX_WORDS * 2];
+#endif
+
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN == 0
+  mg_uecc_vli_bytesToNative(_public, public_key, curve->num_bytes);
+  mg_uecc_vli_bytesToNative(_public + curve->num_words,
+                            public_key + curve->num_bytes, curve->num_bytes);
+#endif
+  return mg_uecc_valid_point(_public, curve);
 }
 
-void mg_unhex(const char *buf, size_t len, unsigned char *to) {
-  size_t i;
-  for (i = 0; i < len; i += 2) {
-    to[i >> 1] = (unsigned char) mg_unhexn(&buf[i], 2);
+int mg_uecc_compute_public_key(const uint8_t *private_key, uint8_t *public_key,
+                               MG_UECC_Curve curve) {
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN
+  mg_uecc_word_t *_private = (mg_uecc_word_t *) private_key;
+  mg_uecc_word_t *_public = (mg_uecc_word_t *) public_key;
+#else
+  mg_uecc_word_t _private[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t _public[MG_UECC_MAX_WORDS * 2];
+#endif
+
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN == 0
+  mg_uecc_vli_bytesToNative(_private, private_key,
+                            BITS_TO_BYTES(curve->num_n_bits));
+#endif
+
+  /* Make sure the private key is in the range [1, n-1]. */
+  if (mg_uecc_vli_isZero(_private, BITS_TO_WORDS(curve->num_n_bits))) {
+    return 0;
   }
-}
 
-uint64_t mg_tou64(struct mg_str str) {
-  uint64_t result = 0;
-  size_t i = 0;
-  while (i < str.len && (str.ptr[i] == ' ' || str.ptr[i] == '\t')) i++;
-  while (i < str.len && str.ptr[i] >= '0' && str.ptr[i] <= '9') {
-    result *= 10;
-    result += (unsigned) (str.ptr[i] - '0');
-    i++;
+  if (mg_uecc_vli_cmp(curve->n, _private, BITS_TO_WORDS(curve->num_n_bits)) !=
+      1) {
+    return 0;
   }
-  return result;
+
+  /* Compute public key. */
+  if (!EccPoint_compute_public_key(_public, _private, curve)) {
+    return 0;
+  }
+
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN == 0
+  mg_uecc_vli_nativeToBytes(public_key, curve->num_bytes, _public);
+  mg_uecc_vli_nativeToBytes(public_key + curve->num_bytes, curve->num_bytes,
+                            _public + curve->num_words);
+#endif
+  return 1;
 }
 
-int64_t mg_to64(struct mg_str str) {
-  int64_t result = 0, neg = 1, max = 922337203685477570 /* INT64_MAX/10-10 */;
-  size_t i = 0;
-  while (i < str.len && (str.ptr[i] == ' ' || str.ptr[i] == '\t')) i++;
-  if (i < str.len && str.ptr[i] == '-') neg = -1, i++;
-  while (i < str.len && str.ptr[i] >= '0' && str.ptr[i] <= '9') {
-    if (result > max) return 0;
-    result *= 10;
-    result += (str.ptr[i] - '0');
-    i++;
+/* -------- ECDSA code -------- */
+
+static void bits2int(mg_uecc_word_t *native, const uint8_t *bits,
+                     unsigned bits_size, MG_UECC_Curve curve) {
+  unsigned num_n_bytes = (unsigned) BITS_TO_BYTES(curve->num_n_bits);
+  unsigned num_n_words = (unsigned) BITS_TO_WORDS(curve->num_n_bits);
+  int shift;
+  mg_uecc_word_t carry;
+  mg_uecc_word_t *ptr;
+
+  if (bits_size > num_n_bytes) {
+    bits_size = num_n_bytes;
+  }
+
+  mg_uecc_vli_clear(native, (wordcount_t) num_n_words);
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN
+  bcopy((uint8_t *) native, bits, bits_size);
+#else
+  mg_uecc_vli_bytesToNative(native, bits, (int) bits_size);
+#endif
+  if (bits_size * 8 <= (unsigned) curve->num_n_bits) {
+    return;
+  }
+  shift = (int) bits_size * 8 - curve->num_n_bits;
+  carry = 0;
+  ptr = native + num_n_words;
+  while (ptr-- > native) {
+    mg_uecc_word_t temp = *ptr;
+    *ptr = (temp >> shift) | carry;
+    carry = temp << (MG_UECC_WORD_BITS - shift);
+  }
+
+  /* Reduce mod curve_n */
+  if (mg_uecc_vli_cmp_unsafe(curve->n, native, (wordcount_t) num_n_words) !=
+      1) {
+    mg_uecc_vli_sub(native, native, curve->n, (wordcount_t) num_n_words);
   }
-  return result * neg;
 }
 
-char *mg_remove_double_dots(char *s) {
-  char *saved = s, *p = s;
-  while (*s != '\0') {
-    *p++ = *s++;
-    if (s[-1] == '/' || s[-1] == '\\') {
-      while (s[0] != '\0') {
-        if (s[0] == '/' || s[0] == '\\') {
-          s++;
-        } else if (s[0] == '.' && s[1] == '.' &&
-                   (s[2] == '/' || s[2] == '\\')) {
-          s += 2;
-        } else {
-          break;
-        }
-      }
+static int mg_uecc_sign_with_k_internal(const uint8_t *private_key,
+                                        const uint8_t *message_hash,
+                                        unsigned hash_size, mg_uecc_word_t *k,
+                                        uint8_t *signature,
+                                        MG_UECC_Curve curve) {
+  mg_uecc_word_t tmp[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t s[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t *k2[2] = {tmp, s};
+  mg_uecc_word_t *initial_Z = 0;
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN
+  mg_uecc_word_t *p = (mg_uecc_word_t *) signature;
+#else
+  mg_uecc_word_t p[MG_UECC_MAX_WORDS * 2];
+#endif
+  mg_uecc_word_t carry;
+  wordcount_t num_words = curve->num_words;
+  wordcount_t num_n_words = BITS_TO_WORDS(curve->num_n_bits);
+  bitcount_t num_n_bits = curve->num_n_bits;
+
+  /* Make sure 0 < k < curve_n */
+  if (mg_uecc_vli_isZero(k, num_words) ||
+      mg_uecc_vli_cmp(curve->n, k, num_n_words) != 1) {
+    return 0;
+  }
+
+  carry = regularize_k(k, tmp, s, curve);
+  /* If an RNG function was specified, try to get a random initial Z value to
+     improve protection against side-channel attacks. */
+  if (g_rng_function) {
+    if (!mg_uecc_generate_random_int(k2[carry], curve->p, num_words)) {
+      return 0;
     }
+    initial_Z = k2[carry];
+  }
+  EccPoint_mult(p, curve->G, k2[!carry], initial_Z,
+                (bitcount_t) (num_n_bits + 1), curve);
+  if (mg_uecc_vli_isZero(p, num_words)) {
+    return 0;
   }
-  *p = '\0';
-  return saved;
-}
 
-#ifdef MG_ENABLE_LINES
-#line 1 "src/timer.c"
+  /* If an RNG function was specified, get a random number
+     to prevent side channel analysis of k. */
+  if (!g_rng_function) {
+    mg_uecc_vli_clear(tmp, num_n_words);
+    tmp[0] = 1;
+  } else if (!mg_uecc_generate_random_int(tmp, curve->n, num_n_words)) {
+    return 0;
+  }
+
+  /* Prevent side channel analysis of mg_uecc_vli_modInv() to determine
+     bits of k / the private key by premultiplying by a random number */
+  mg_uecc_vli_modMult(k, k, tmp, curve->n, num_n_words); /* k' = rand * k */
+  mg_uecc_vli_modInv(k, k, curve->n, num_n_words);       /* k = 1 / k' */
+  mg_uecc_vli_modMult(k, k, tmp, curve->n, num_n_words); /* k = 1 / k */
+
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN == 0
+  mg_uecc_vli_nativeToBytes(signature, curve->num_bytes, p); /* store r */
 #endif
 
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN
+  bcopy((uint8_t *) tmp, private_key, BITS_TO_BYTES(curve->num_n_bits));
+#else
+  mg_uecc_vli_bytesToNative(tmp, private_key,
+                            BITS_TO_BYTES(curve->num_n_bits)); /* tmp = d */
+#endif
 
+  s[num_n_words - 1] = 0;
+  mg_uecc_vli_set(s, p, num_words);
+  mg_uecc_vli_modMult(s, tmp, s, curve->n, num_n_words); /* s = r*d */
 
-#define MG_TIMER_CALLED 4
+  bits2int(tmp, message_hash, hash_size, curve);
+  mg_uecc_vli_modAdd(s, tmp, s, curve->n, num_n_words); /* s = e + r*d */
+  mg_uecc_vli_modMult(s, s, k, curve->n, num_n_words);  /* s = (e + r*d) / k */
+  if (mg_uecc_vli_numBits(s, num_n_words) > (bitcount_t) curve->num_bytes * 8) {
+    return 0;
+  }
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN
+  bcopy((uint8_t *) signature + curve->num_bytes, (uint8_t *) s,
+        curve->num_bytes);
+#else
+  mg_uecc_vli_nativeToBytes(signature + curve->num_bytes, curve->num_bytes, s);
+#endif
+  return 1;
+}
 
-void mg_timer_init(struct mg_timer **head, struct mg_timer *t, uint64_t ms,
-                   unsigned flags, void (*fn)(void *), void *arg) {
-  t->id = 0, t->period_ms = ms, t->expire = 0;
-  t->flags = flags, t->fn = fn, t->arg = arg, t->next = *head;
-  *head = t;
+#if 0
+/* For testing - sign with an explicitly specified k value */
+int mg_uecc_sign_with_k(const uint8_t *private_key, const uint8_t *message_hash,
+                     unsigned hash_size, const uint8_t *k, uint8_t *signature,
+                     MG_UECC_Curve curve) {
+  mg_uecc_word_t k2[MG_UECC_MAX_WORDS];
+  bits2int(k2, k, (unsigned) BITS_TO_BYTES(curve->num_n_bits), curve);
+  return mg_uecc_sign_with_k_internal(private_key, message_hash, hash_size, k2,
+                                   signature, curve);
 }
+#endif
 
-void mg_timer_free(struct mg_timer **head, struct mg_timer *t) {
-  while (*head && *head != t) head = &(*head)->next;
-  if (*head) *head = t->next;
+int mg_uecc_sign(const uint8_t *private_key, const uint8_t *message_hash,
+                 unsigned hash_size, uint8_t *signature, MG_UECC_Curve curve) {
+  mg_uecc_word_t k[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t tries;
+
+  for (tries = 0; tries < MG_UECC_RNG_MAX_TRIES; ++tries) {
+    if (!mg_uecc_generate_random_int(k, curve->n,
+                                     BITS_TO_WORDS(curve->num_n_bits))) {
+      return 0;
+    }
+
+    if (mg_uecc_sign_with_k_internal(private_key, message_hash, hash_size, k,
+                                     signature, curve)) {
+      return 1;
+    }
+  }
+  return 0;
 }
 
-// t: expiration time, prd: period, now: current time. Return true if expired
-bool mg_timer_expired(uint64_t *t, uint64_t prd, uint64_t now) {
-  if (now + prd < *t) *t = 0;                    // Time wrapped? Reset timer
-  if (*t == 0) *t = now + prd;                   // Firt poll? Set expiration
-  if (*t > now) return false;                    // Not expired yet, return
-  *t = (now - *t) > prd ? now + prd : *t + prd;  // Next expiration time
-  return true;                                   // Expired, return true
+/* Compute an HMAC using K as a key (as in RFC 6979). Note that K is always
+   the same size as the hash result size. */
+static void HMAC_init(const MG_UECC_HashContext *hash_context,
+                      const uint8_t *K) {
+  uint8_t *pad = hash_context->tmp + 2 * hash_context->result_size;
+  unsigned i;
+  for (i = 0; i < hash_context->result_size; ++i) pad[i] = K[i] ^ 0x36;
+  for (; i < hash_context->block_size; ++i) pad[i] = 0x36;
+
+  hash_context->init_hash(hash_context);
+  hash_context->update_hash(hash_context, pad, hash_context->block_size);
 }
 
-void mg_timer_poll(struct mg_timer **head, uint64_t now_ms) {
-  struct mg_timer *t, *tmp;
-  for (t = *head; t != NULL; t = tmp) {
-    bool once = t->expire == 0 && (t->flags & MG_TIMER_RUN_NOW) &&
-                !(t->flags & MG_TIMER_CALLED);  // Handle MG_TIMER_NOW only once
-    bool expired = mg_timer_expired(&t->expire, t->period_ms, now_ms);
-    tmp = t->next;
-    if (!once && !expired) continue;
-    if ((t->flags & MG_TIMER_REPEAT) || !(t->flags & MG_TIMER_CALLED)) {
-      t->fn(t->arg);
+static void HMAC_update(const MG_UECC_HashContext *hash_context,
+                        const uint8_t *message, unsigned message_size) {
+  hash_context->update_hash(hash_context, message, message_size);
+}
+
+static void HMAC_finish(const MG_UECC_HashContext *hash_context,
+                        const uint8_t *K, uint8_t *result) {
+  uint8_t *pad = hash_context->tmp + 2 * hash_context->result_size;
+  unsigned i;
+  for (i = 0; i < hash_context->result_size; ++i) pad[i] = K[i] ^ 0x5c;
+  for (; i < hash_context->block_size; ++i) pad[i] = 0x5c;
+
+  hash_context->finish_hash(hash_context, result);
+
+  hash_context->init_hash(hash_context);
+  hash_context->update_hash(hash_context, pad, hash_context->block_size);
+  hash_context->update_hash(hash_context, result, hash_context->result_size);
+  hash_context->finish_hash(hash_context, result);
+}
+
+/* V = HMAC_K(V) */
+static void update_V(const MG_UECC_HashContext *hash_context, uint8_t *K,
+                     uint8_t *V) {
+  HMAC_init(hash_context, K);
+  HMAC_update(hash_context, V, hash_context->result_size);
+  HMAC_finish(hash_context, K, V);
+}
+
+/* Deterministic signing, similar to RFC 6979. Differences are:
+    * We just use H(m) directly rather than bits2octets(H(m))
+      (it is not reduced modulo curve_n).
+    * We generate a value for k (aka T) directly rather than converting
+   endianness.
+
+   Layout of hash_context->tmp: <K> | <V> | (1 byte overlapped 0x00 or 0x01) /
+   <HMAC pad> */
+int mg_uecc_sign_deterministic(const uint8_t *private_key,
+                               const uint8_t *message_hash, unsigned hash_size,
+                               const MG_UECC_HashContext *hash_context,
+                               uint8_t *signature, MG_UECC_Curve curve) {
+  uint8_t *K = hash_context->tmp;
+  uint8_t *V = K + hash_context->result_size;
+  wordcount_t num_bytes = curve->num_bytes;
+  wordcount_t num_n_words = BITS_TO_WORDS(curve->num_n_bits);
+  bitcount_t num_n_bits = curve->num_n_bits;
+  mg_uecc_word_t tries;
+  unsigned i;
+  for (i = 0; i < hash_context->result_size; ++i) {
+    V[i] = 0x01;
+    K[i] = 0;
+  }
+
+  /* K = HMAC_K(V || 0x00 || int2octets(x) || h(m)) */
+  HMAC_init(hash_context, K);
+  V[hash_context->result_size] = 0x00;
+  HMAC_update(hash_context, V, hash_context->result_size + 1);
+  HMAC_update(hash_context, private_key, (unsigned int) num_bytes);
+  HMAC_update(hash_context, message_hash, hash_size);
+  HMAC_finish(hash_context, K, K);
+
+  update_V(hash_context, K, V);
+
+  /* K = HMAC_K(V || 0x01 || int2octets(x) || h(m)) */
+  HMAC_init(hash_context, K);
+  V[hash_context->result_size] = 0x01;
+  HMAC_update(hash_context, V, hash_context->result_size + 1);
+  HMAC_update(hash_context, private_key, (unsigned int) num_bytes);
+  HMAC_update(hash_context, message_hash, hash_size);
+  HMAC_finish(hash_context, K, K);
+
+  update_V(hash_context, K, V);
+
+  for (tries = 0; tries < MG_UECC_RNG_MAX_TRIES; ++tries) {
+    mg_uecc_word_t T[MG_UECC_MAX_WORDS];
+    uint8_t *T_ptr = (uint8_t *) T;
+    wordcount_t T_bytes = 0;
+    for (;;) {
+      update_V(hash_context, K, V);
+      for (i = 0; i < hash_context->result_size; ++i) {
+        T_ptr[T_bytes++] = V[i];
+        if (T_bytes >= num_n_words * MG_UECC_WORD_SIZE) {
+          goto filled;
+        }
+      }
+    }
+  filled:
+    if ((bitcount_t) num_n_words * MG_UECC_WORD_SIZE * 8 > num_n_bits) {
+      mg_uecc_word_t mask = (mg_uecc_word_t) -1;
+      T[num_n_words - 1] &=
+          mask >>
+          ((bitcount_t) (num_n_words * MG_UECC_WORD_SIZE * 8 - num_n_bits));
+    }
+
+    if (mg_uecc_sign_with_k_internal(private_key, message_hash, hash_size, T,
+                                     signature, curve)) {
+      return 1;
     }
-    t->flags |= MG_TIMER_CALLED;
+
+    /* K = HMAC_K(V || 0x00) */
+    HMAC_init(hash_context, K);
+    V[hash_context->result_size] = 0x00;
+    HMAC_update(hash_context, V, hash_context->result_size + 1);
+    HMAC_finish(hash_context, K, K);
+
+    update_V(hash_context, K, V);
   }
+  return 0;
 }
 
-#ifdef MG_ENABLE_LINES
-#line 1 "src/tls_dummy.c"
+static bitcount_t smax(bitcount_t a, bitcount_t b) {
+  return (a > b ? a : b);
+}
+
+int mg_uecc_verify(const uint8_t *public_key, const uint8_t *message_hash,
+                   unsigned hash_size, const uint8_t *signature,
+                   MG_UECC_Curve curve) {
+  mg_uecc_word_t u1[MG_UECC_MAX_WORDS], u2[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t z[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t sum[MG_UECC_MAX_WORDS * 2];
+  mg_uecc_word_t rx[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t ry[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t tx[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t ty[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t tz[MG_UECC_MAX_WORDS];
+  const mg_uecc_word_t *points[4];
+  const mg_uecc_word_t *point;
+  bitcount_t num_bits;
+  bitcount_t i;
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN
+  mg_uecc_word_t *_public = (mg_uecc_word_t *) public_key;
+#else
+  mg_uecc_word_t _public[MG_UECC_MAX_WORDS * 2];
 #endif
+  mg_uecc_word_t r[MG_UECC_MAX_WORDS], s[MG_UECC_MAX_WORDS];
+  wordcount_t num_words = curve->num_words;
+  wordcount_t num_n_words = BITS_TO_WORDS(curve->num_n_bits);
 
+  rx[num_n_words - 1] = 0;
+  r[num_n_words - 1] = 0;
+  s[num_n_words - 1] = 0;
 
-#if !MG_ENABLE_MBEDTLS && !MG_ENABLE_OPENSSL && !MG_ENABLE_CUSTOM_TLS
-void mg_tls_init(struct mg_connection *c, const struct mg_tls_opts *opts) {
-  (void) opts;
-  mg_error(c, "TLS is not enabled");
-}
-void mg_tls_handshake(struct mg_connection *c) {
-  (void) c;
-}
-void mg_tls_free(struct mg_connection *c) {
-  (void) c;
-}
-long mg_tls_recv(struct mg_connection *c, void *buf, size_t len) {
-  return c == NULL || buf == NULL || len == 0 ? 0 : -1;
-}
-long mg_tls_send(struct mg_connection *c, const void *buf, size_t len) {
-  return c == NULL || buf == NULL || len == 0 ? 0 : -1;
-}
-size_t mg_tls_pending(struct mg_connection *c) {
-  (void) c;
-  return 0;
-}
+#if MG_UECC_VLI_NATIVE_LITTLE_ENDIAN
+  bcopy((uint8_t *) r, signature, curve->num_bytes);
+  bcopy((uint8_t *) s, signature + curve->num_bytes, curve->num_bytes);
+#else
+  mg_uecc_vli_bytesToNative(_public, public_key, curve->num_bytes);
+  mg_uecc_vli_bytesToNative(_public + num_words, public_key + curve->num_bytes,
+                            curve->num_bytes);
+  mg_uecc_vli_bytesToNative(r, signature, curve->num_bytes);
+  mg_uecc_vli_bytesToNative(s, signature + curve->num_bytes, curve->num_bytes);
 #endif
 
-#ifdef MG_ENABLE_LINES
-#line 1 "src/tls_mbed.c"
-#endif
+  /* r, s must not be 0. */
+  if (mg_uecc_vli_isZero(r, num_words) || mg_uecc_vli_isZero(s, num_words)) {
+    return 0;
+  }
 
+  /* r, s must be < n. */
+  if (mg_uecc_vli_cmp_unsafe(curve->n, r, num_n_words) != 1 ||
+      mg_uecc_vli_cmp_unsafe(curve->n, s, num_n_words) != 1) {
+    return 0;
+  }
 
+  /* Calculate u1 and u2. */
+  mg_uecc_vli_modInv(z, s, curve->n, num_n_words); /* z = 1/s */
+  u1[num_n_words - 1] = 0;
+  bits2int(u1, message_hash, hash_size, curve);
+  mg_uecc_vli_modMult(u1, u1, z, curve->n, num_n_words); /* u1 = e/s */
+  mg_uecc_vli_modMult(u2, r, z, curve->n, num_n_words);  /* u2 = r/s */
+
+  /* Calculate sum = G + Q. */
+  mg_uecc_vli_set(sum, _public, num_words);
+  mg_uecc_vli_set(sum + num_words, _public + num_words, num_words);
+  mg_uecc_vli_set(tx, curve->G, num_words);
+  mg_uecc_vli_set(ty, curve->G + num_words, num_words);
+  mg_uecc_vli_modSub(z, sum, tx, curve->p, num_words); /* z = x2 - x1 */
+  XYcZ_add(tx, ty, sum, sum + num_words, curve);
+  mg_uecc_vli_modInv(z, z, curve->p, num_words); /* z = 1/z */
+  apply_z(sum, sum + num_words, z, curve);
+
+  /* Use Shamir's trick to calculate u1*G + u2*Q */
+  points[0] = 0;
+  points[1] = curve->G;
+  points[2] = _public;
+  points[3] = sum;
+  num_bits = smax(mg_uecc_vli_numBits(u1, num_n_words),
+                  mg_uecc_vli_numBits(u2, num_n_words));
+  point =
+      points[(!!mg_uecc_vli_testBit(u1, (bitcount_t) (num_bits - 1))) |
+             ((!!mg_uecc_vli_testBit(u2, (bitcount_t) (num_bits - 1))) << 1)];
+  mg_uecc_vli_set(rx, point, num_words);
+  mg_uecc_vli_set(ry, point + num_words, num_words);
+  mg_uecc_vli_clear(z, num_words);
+  z[0] = 1;
+
+  for (i = num_bits - 2; i >= 0; --i) {
+    mg_uecc_word_t index;
+    curve->double_jacobian(rx, ry, z, curve);
+
+    index = (!!mg_uecc_vli_testBit(u1, i)) |
+            (mg_uecc_word_t) ((!!mg_uecc_vli_testBit(u2, i)) << 1);
+    point = points[index];
+    if (point) {
+      mg_uecc_vli_set(tx, point, num_words);
+      mg_uecc_vli_set(ty, point + num_words, num_words);
+      apply_z(tx, ty, z, curve);
+      mg_uecc_vli_modSub(tz, rx, tx, curve->p, num_words); /* Z = x2 - x1 */
+      XYcZ_add(tx, ty, rx, ry, curve);
+      mg_uecc_vli_modMult_fast(z, z, tz, curve);
+    }
+  }
 
+  mg_uecc_vli_modInv(z, z, curve->p, num_words); /* Z = 1/Z */
+  apply_z(rx, ry, z, curve);
 
-#if MG_ENABLE_MBEDTLS
+  /* v = x1 (mod n) */
+  if (mg_uecc_vli_cmp_unsafe(curve->n, rx, num_n_words) != 1) {
+    mg_uecc_vli_sub(rx, rx, curve->n, num_n_words);
+  }
 
-#if defined(MBEDTLS_VERSION_NUMBER) && MBEDTLS_VERSION_NUMBER >= 0x03000000
-#define MGRNG , rng_get, NULL
-#else
-#define MGRNG
-#endif
+  /* Accept only if v == r. */
+  return (int) (mg_uecc_vli_equal(rx, r, num_words));
+}
 
-void mg_tls_free(struct mg_connection *c) {
-  struct mg_tls *tls = (struct mg_tls *) c->tls;
-  if (tls != NULL) {
-    free(tls->cafile);
-    mbedtls_ssl_free(&tls->ssl);
-    mbedtls_pk_free(&tls->pk);
-    mbedtls_x509_crt_free(&tls->ca);
-    mbedtls_x509_crt_free(&tls->cert);
-    mbedtls_ssl_config_free(&tls->conf);
-    free(tls);
-    c->tls = NULL;
-  }
+#if MG_UECC_ENABLE_VLI_API
+
+unsigned mg_uecc_curve_num_words(MG_UECC_Curve curve) {
+  return curve->num_words;
 }
 
-static int mg_net_send(void *ctx, const unsigned char *buf, size_t len) {
-  long n = mg_io_send((struct mg_connection *) ctx, buf, len);
-  MG_VERBOSE(("%lu n=%ld", ((struct mg_connection *) ctx)->id, n));
-  if (n == MG_IO_WAIT) return MBEDTLS_ERR_SSL_WANT_WRITE;
-  if (n == MG_IO_RESET) return MBEDTLS_ERR_NET_CONN_RESET;
-  if (n == MG_IO_ERR) return MBEDTLS_ERR_NET_SEND_FAILED;
-  return (int) n;
+unsigned mg_uecc_curve_num_bytes(MG_UECC_Curve curve) {
+  return curve->num_bytes;
 }
 
-static int mg_net_recv(void *ctx, unsigned char *buf, size_t len) {
-  long n = mg_io_recv((struct mg_connection *) ctx, buf, len);
-  MG_VERBOSE(("%lu n=%ld", ((struct mg_connection *) ctx)->id, n));
-  if (n == MG_IO_WAIT) return MBEDTLS_ERR_SSL_WANT_WRITE;
-  if (n == MG_IO_RESET) return MBEDTLS_ERR_NET_CONN_RESET;
-  if (n == MG_IO_ERR) return MBEDTLS_ERR_NET_RECV_FAILED;
-  return (int) n;
+unsigned mg_uecc_curve_num_bits(MG_UECC_Curve curve) {
+  return curve->num_bytes * 8;
 }
 
-void mg_tls_handshake(struct mg_connection *c) {
-  struct mg_tls *tls = (struct mg_tls *) c->tls;
-  int rc = mbedtls_ssl_handshake(&tls->ssl);
-  if (rc == 0) {  // Success
-    MG_DEBUG(("%lu success", c->id));
-    c->is_tls_hs = 0;
-    mg_call(c, MG_EV_TLS_HS, NULL);
-  } else if (rc == MBEDTLS_ERR_SSL_WANT_READ ||
-             rc == MBEDTLS_ERR_SSL_WANT_WRITE) {  // Still pending
-    MG_VERBOSE(("%lu pending, %d%d %d (-%#x)", c->id, c->is_connecting,
-                c->is_tls_hs, rc, -rc));
-  } else {
-    mg_error(c, "TLS handshake: -%#x", -rc);  // Error
-  }
+unsigned mg_uecc_curve_num_n_words(MG_UECC_Curve curve) {
+  return BITS_TO_WORDS(curve->num_n_bits);
 }
 
-static int mbed_rng(void *ctx, unsigned char *buf, size_t len) {
-  mg_random(buf, len);
-  (void) ctx;
-  return 0;
+unsigned mg_uecc_curve_num_n_bytes(MG_UECC_Curve curve) {
+  return BITS_TO_BYTES(curve->num_n_bits);
 }
 
-static void debug_cb(void *c, int lev, const char *s, int n, const char *s2) {
-  n = (int) strlen(s2) - 1;
-  MG_VERBOSE(("%lu %d %.*s", ((struct mg_connection *) c)->id, lev, n, s2));
-  (void) s;
+unsigned mg_uecc_curve_num_n_bits(MG_UECC_Curve curve) {
+  return curve->num_n_bits;
 }
 
-#if defined(MBEDTLS_VERSION_NUMBER) && MBEDTLS_VERSION_NUMBER >= 0x03000000
-static int rng_get(void *p_rng, unsigned char *buf, size_t len) {
-  (void) p_rng;
-  mg_random(buf, len);
-  return 0;
+const mg_uecc_word_t *mg_uecc_curve_p(MG_UECC_Curve curve) {
+  return curve->p;
 }
-#endif
 
-static struct mg_str mg_loadfile(struct mg_fs *fs, const char *path) {
-  size_t n = 0;
-  if (path[0] == '-') return mg_str(path);
-  char *p = mg_file_read(fs, path, &n);
-  return mg_str_n(p, n);
+const mg_uecc_word_t *mg_uecc_curve_n(MG_UECC_Curve curve) {
+  return curve->n;
 }
 
-void mg_tls_init(struct mg_connection *c, const struct mg_tls_opts *opts) {
-  struct mg_fs *fs = opts->fs == NULL ? &mg_fs_posix : opts->fs;
-  struct mg_tls *tls = (struct mg_tls *) calloc(1, sizeof(*tls));
-  int rc = 0;
-  c->tls = tls;
-  if (c->tls == NULL) {
-    mg_error(c, "TLS OOM");
-    goto fail;
-  }
-  MG_DEBUG(("%lu Setting TLS", c->id));
-  mbedtls_ssl_init(&tls->ssl);
-  mbedtls_ssl_config_init(&tls->conf);
-  mbedtls_x509_crt_init(&tls->ca);
-  mbedtls_x509_crt_init(&tls->cert);
-  mbedtls_pk_init(&tls->pk);
-  mbedtls_ssl_conf_dbg(&tls->conf, debug_cb, c);
-#if defined(MG_MBEDTLS_DEBUG_LEVEL)
-  mbedtls_debug_set_threshold(MG_MBEDTLS_DEBUG_LEVEL);
+const mg_uecc_word_t *mg_uecc_curve_G(MG_UECC_Curve curve) {
+  return curve->G;
+}
+
+const mg_uecc_word_t *mg_uecc_curve_b(MG_UECC_Curve curve) {
+  return curve->b;
+}
+
+#if MG_UECC_SUPPORT_COMPRESSED_POINT
+void mg_uecc_vli_mod_sqrt(mg_uecc_word_t *a, MG_UECC_Curve curve) {
+  curve->mod_sqrt(a, curve);
+}
 #endif
-  if ((rc = mbedtls_ssl_config_defaults(
-           &tls->conf,
-           c->is_client ? MBEDTLS_SSL_IS_CLIENT : MBEDTLS_SSL_IS_SERVER,
-           MBEDTLS_SSL_TRANSPORT_STREAM, MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
-    mg_error(c, "tls defaults %#x", -rc);
-    goto fail;
-  }
-  mbedtls_ssl_conf_rng(&tls->conf, mbed_rng, c);
-  if (opts->ca == NULL || strcmp(opts->ca, "*") == 0) {
-    mbedtls_ssl_conf_authmode(&tls->conf, MBEDTLS_SSL_VERIFY_NONE);
-  } else if (opts->ca != NULL && opts->ca[0] != '\0') {
-#if defined(MBEDTLS_X509_CA_CHAIN_ON_DISK)
-    tls->cafile = strdup(opts->ca);
-    rc = mbedtls_ssl_conf_ca_chain_file(&tls->conf, tls->cafile, NULL);
-    if (rc != 0) {
-      mg_error(c, "parse on-disk chain(%s) err %#x", tls->cafile, -rc);
-      goto fail;
-    }
+
+void mg_uecc_vli_mmod_fast(mg_uecc_word_t *result, mg_uecc_word_t *product,
+                           MG_UECC_Curve curve) {
+#if (MG_UECC_OPTIMIZATION_LEVEL > 0)
+  curve->mmod_fast(result, product);
 #else
-    struct mg_str s = mg_loadfile(fs, opts->ca);
-    rc = mbedtls_x509_crt_parse(&tls->ca, (uint8_t *) s.ptr, s.len + 1);
-    if (opts->ca[0] != '-') free((char *) s.ptr);
-    if (rc != 0) {
-      mg_error(c, "parse(%s) err %#x", opts->ca, -rc);
-      goto fail;
-    }
-    mbedtls_ssl_conf_ca_chain(&tls->conf, &tls->ca, NULL);
+  mg_uecc_vli_mmod(result, product, curve->p, curve->num_words);
 #endif
-    if (opts->srvname.len > 0) {
-      char *x = mg_mprintf("%.*s", (int) opts->srvname.len, opts->srvname.ptr);
-      mbedtls_ssl_set_hostname(&tls->ssl, x);
-      free(x);
-    }
-    mbedtls_ssl_conf_authmode(&tls->conf, MBEDTLS_SSL_VERIFY_REQUIRED);
-  }
-  if (opts->cert != NULL && opts->cert[0] != '\0') {
-    struct mg_str s = mg_loadfile(fs, opts->cert);
-    const char *key = opts->certkey == NULL ? opts->cert : opts->certkey;
-    rc = mbedtls_x509_crt_parse(&tls->cert, (uint8_t *) s.ptr, s.len + 1);
-    if (opts->cert[0] != '-') free((char *) s.ptr);
-    if (rc != 0) {
-      mg_error(c, "parse(%s) err %#x", opts->cert, -rc);
-      goto fail;
-    }
-    s = mg_loadfile(fs, key);
-    rc = mbedtls_pk_parse_key(&tls->pk, (uint8_t *) s.ptr, s.len + 1, NULL,
-                              0 MGRNG);
-    if (key[0] != '-') free((char *) s.ptr);
-    if (rc != 0) {
-      mg_error(c, "tls key(%s) %#x", key, -rc);
-      goto fail;
-    }
-    rc = mbedtls_ssl_conf_own_cert(&tls->conf, &tls->cert, &tls->pk);
-    if (rc != 0) {
-      mg_error(c, "own cert %#x", -rc);
-      goto fail;
-    }
-  }
-  if ((rc = mbedtls_ssl_setup(&tls->ssl, &tls->conf)) != 0) {
-    mg_error(c, "setup err %#x", -rc);
-    goto fail;
-  }
-  c->tls = tls;
-  c->is_tls = 1;
-  c->is_tls_hs = 1;
-  mbedtls_ssl_set_bio(&tls->ssl, c, mg_net_send, mg_net_recv, 0);
-  if (c->is_client && c->is_resolving == 0 && c->is_connecting == 0) {
-    mg_tls_handshake(c);
-  }
-  return;
-fail:
-  mg_tls_free(c);
 }
 
-size_t mg_tls_pending(struct mg_connection *c) {
-  struct mg_tls *tls = (struct mg_tls *) c->tls;
-  return tls == NULL ? 0 : mbedtls_ssl_get_bytes_avail(&tls->ssl);
-}
+void mg_uecc_point_mult(mg_uecc_word_t *result, const mg_uecc_word_t *point,
+                        const mg_uecc_word_t *scalar, MG_UECC_Curve curve) {
+  mg_uecc_word_t tmp1[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t tmp2[MG_UECC_MAX_WORDS];
+  mg_uecc_word_t *p2[2] = {tmp1, tmp2};
+  mg_uecc_word_t carry = regularize_k(scalar, tmp1, tmp2, curve);
 
-long mg_tls_recv(struct mg_connection *c, void *buf, size_t len) {
-  struct mg_tls *tls = (struct mg_tls *) c->tls;
-  long n = mbedtls_ssl_read(&tls->ssl, (unsigned char *) buf, len);
-  if (n == MBEDTLS_ERR_SSL_WANT_READ || n == MBEDTLS_ERR_SSL_WANT_WRITE)
-    return MG_IO_WAIT;
-  if (n <= 0) return MG_IO_ERR;
-  return n;
+  EccPoint_mult(result, point, p2[!carry], 0, curve->num_n_bits + 1, curve);
 }
 
-long mg_tls_send(struct mg_connection *c, const void *buf, size_t len) {
-  struct mg_tls *tls = (struct mg_tls *) c->tls;
-  long n = mbedtls_ssl_write(&tls->ssl, (unsigned char *) buf, len);
-  if (n == MBEDTLS_ERR_SSL_WANT_READ || n == MBEDTLS_ERR_SSL_WANT_WRITE)
-    return MG_IO_WAIT;
-  if (n <= 0) return MG_IO_ERR;
-  return n;
-}
-#endif
+#endif  /* MG_UECC_ENABLE_VLI_API */
+#endif  // MG_TLS_BUILTIN
+// End of uecc BSD-2
 
 #ifdef MG_ENABLE_LINES
-#line 1 "src/tls_openssl.c"
+#line 1 "src/tls_x25519.c"
 #endif
+/**
+ * Adapted from STROBE: https://strobe.sourceforge.io/
+ * Copyright (c) 2015-2016 Cryptography Research, Inc.
+ * Author: Mike Hamburg
+ * License: MIT License
+ */
 
 
 
-#if MG_ENABLE_OPENSSL
-static int mg_tls_err(struct mg_tls *tls, int res) {
-  int err = SSL_get_error(tls->ssl, res);
-  // We've just fetched the last error from the queue.
-  // Now we need to clear the error queue. If we do not, then the following
-  // can happen (actually reported):
-  //  - A new connection is accept()-ed with cert error (e.g. self-signed cert)
-  //  - Since all accept()-ed connections share listener's context,
-  //  - *ALL* SSL accepted connection report read error on the next poll cycle.
-  //    Thus a single errored connection can close all the rest, unrelated ones.
-  // Clearing the error keeps the shared SSL_CTX in an OK state.
+const uint8_t X25519_BASE_POINT[X25519_BYTES] = {9};
 
-  if (err != 0) ERR_print_errors_fp(stderr);
-  ERR_clear_error();
-  if (err == SSL_ERROR_WANT_READ) return 0;
-  if (err == SSL_ERROR_WANT_WRITE) return 0;
-  return err;
-}
+#define X25519_WBITS 32
 
-void mg_tls_init(struct mg_connection *c, const struct mg_tls_opts *opts) {
-  struct mg_tls *tls = (struct mg_tls *) calloc(1, sizeof(*tls));
-  const char *id = "mongoose";
-  static unsigned char s_initialised = 0;
-  int rc;
+typedef uint32_t limb_t;
+typedef uint64_t dlimb_t;
+typedef int64_t sdlimb_t;
 
-  if (tls == NULL) {
-    mg_error(c, "TLS OOM");
-    goto fail;
-  }
+#define NLIMBS (256 / X25519_WBITS)
+typedef limb_t mg_fe[NLIMBS];
 
-  if (!s_initialised) {
-    SSL_library_init();
-    s_initialised++;
-  }
-  MG_DEBUG(("%lu Setting TLS, CA: %s, cert: %s, key: %s", c->id,
-            opts->ca == NULL ? "null" : opts->ca,
-            opts->cert == NULL ? "null" : opts->cert,
-            opts->certkey == NULL ? "null" : opts->certkey));
-  tls->ctx = c->is_client ? SSL_CTX_new(SSLv23_client_method())
-                          : SSL_CTX_new(SSLv23_server_method());
-  if ((tls->ssl = SSL_new(tls->ctx)) == NULL) {
-    mg_error(c, "SSL_new");
-    goto fail;
-  }
-  SSL_set_session_id_context(tls->ssl, (const uint8_t *) id,
-                             (unsigned) strlen(id));
-  // Disable deprecated protocols
-  SSL_set_options(tls->ssl, SSL_OP_NO_SSLv2);
-  SSL_set_options(tls->ssl, SSL_OP_NO_SSLv3);
-  SSL_set_options(tls->ssl, SSL_OP_NO_TLSv1);
-  SSL_set_options(tls->ssl, SSL_OP_NO_TLSv1_1);
-#ifdef MG_ENABLE_OPENSSL_NO_COMPRESSION
-  SSL_set_options(tls->ssl, SSL_OP_NO_COMPRESSION);
-#endif
-#ifdef MG_ENABLE_OPENSSL_CIPHER_SERVER_PREFERENCE
-  SSL_set_options(tls->ssl, SSL_OP_CIPHER_SERVER_PREFERENCE);
-#endif
+static limb_t umaal(limb_t *carry, limb_t acc, limb_t mand, limb_t mier) {
+  dlimb_t tmp = (dlimb_t) mand * mier + acc + *carry;
+  *carry = (limb_t) (tmp >> X25519_WBITS);
+  return (limb_t) tmp;
+}
 
-  if (opts->ca != NULL && opts->ca[0] != '\0') {
-    SSL_set_verify(tls->ssl, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
-                   NULL);
-    if ((rc = SSL_CTX_load_verify_locations(tls->ctx, opts->ca, NULL)) != 1) {
-      mg_error(c, "load('%s') %d err %d", opts->ca, rc, mg_tls_err(tls, rc));
-      goto fail;
-    }
-  }
-  if (opts->cert != NULL && opts->cert[0] != '\0') {
-    const char *key = opts->certkey;
-    if (key == NULL) key = opts->cert;
-    if ((rc = SSL_use_certificate_file(tls->ssl, opts->cert, 1)) != 1) {
-      mg_error(c, "Invalid SSL cert, err %d", mg_tls_err(tls, rc));
-      goto fail;
-    } else if ((rc = SSL_use_PrivateKey_file(tls->ssl, key, 1)) != 1) {
-      mg_error(c, "Invalid SSL key, err %d", mg_tls_err(tls, rc));
-      goto fail;
-#if OPENSSL_VERSION_NUMBER > 0x10100000L
-    } else if ((rc = SSL_use_certificate_chain_file(tls->ssl, opts->cert)) !=
-               1) {
-      mg_error(c, "Invalid chain, err %d", mg_tls_err(tls, rc));
-      goto fail;
-#endif
-    } else {
-      SSL_set_mode(tls->ssl, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
-#if OPENSSL_VERSION_NUMBER > 0x10002000L
-      SSL_set_ecdh_auto(tls->ssl, 1);
-#endif
-    }
-  }
-  if (opts->ciphers != NULL) SSL_set_cipher_list(tls->ssl, opts->ciphers);
-#if OPENSSL_VERSION_NUMBER >= 0x10100000L
-  if (opts->srvname.len > 0) {
-    char *s = mg_mprintf("%.*s", (int) opts->srvname.len, opts->srvname.ptr);
-    SSL_set1_host(tls->ssl, s);
-    free(s);
-  }
-#endif
-  c->tls = tls;
-  c->is_tls = 1;
-  c->is_tls_hs = 1;
-  if (c->is_client && c->is_resolving == 0 && c->is_connecting == 0) {
-    mg_tls_handshake(c);
-  }
-  MG_DEBUG(("%lu SSL %s OK", c->id, c->is_accepted ? "accept" : "client"));
-  return;
-fail:
-  c->is_closing = 1;
-  free(tls);
+// These functions are implemented in terms of umaal on ARM
+static limb_t adc(limb_t *carry, limb_t acc, limb_t mand) {
+  dlimb_t total = (dlimb_t) *carry + acc + mand;
+  *carry = (limb_t) (total >> X25519_WBITS);
+  return (limb_t) total;
+}
+
+static limb_t adc0(limb_t *carry, limb_t acc) {
+  dlimb_t total = (dlimb_t) *carry + acc;
+  *carry = (limb_t) (total >> X25519_WBITS);
+  return (limb_t) total;
+}
+
+// - Precondition: carry is small.
+// - Invariant: result of propagate is < 2^255 + 1 word
+// - In particular, always less than 2p.
+// - Also, output x >= min(x,19)
+static void propagate(mg_fe x, limb_t over) {
+  unsigned i;
+  limb_t carry;
+  over = x[NLIMBS - 1] >> (X25519_WBITS - 1) | over << 1;
+  x[NLIMBS - 1] &= ~((limb_t) 1 << (X25519_WBITS - 1));
+
+  carry = over * 19;
+  for (i = 0; i < NLIMBS; i++) {
+    x[i] = adc0(&carry, x[i]);
+  }
 }
 
-void mg_tls_handshake(struct mg_connection *c) {
-  struct mg_tls *tls = (struct mg_tls *) c->tls;
-  int rc;
-  SSL_set_fd(tls->ssl, (int) (size_t) c->fd);
-  rc = c->is_client ? SSL_connect(tls->ssl) : SSL_accept(tls->ssl);
-  if (rc == 1) {
-    MG_DEBUG(("%lu success", c->id));
-    c->is_tls_hs = 0;
-    mg_call(c, MG_EV_TLS_HS, NULL);
-  } else {
-    int code = mg_tls_err(tls, rc);
-    if (code != 0) mg_error(c, "tls hs: rc %d, err %d", rc, code);
+static void add(mg_fe out, const mg_fe a, const mg_fe b) {
+  unsigned i;
+  limb_t carry = 0;
+  for (i = 0; i < NLIMBS; i++) {
+    out[i] = adc(&carry, a[i], b[i]);
   }
+  propagate(out, carry);
 }
 
-void mg_tls_free(struct mg_connection *c) {
-  struct mg_tls *tls = (struct mg_tls *) c->tls;
-  if (tls == NULL) return;
-  SSL_free(tls->ssl);
-  SSL_CTX_free(tls->ctx);
-  free(tls);
-  c->tls = NULL;
+static void sub(mg_fe out, const mg_fe a, const mg_fe b) {
+  unsigned i;
+  sdlimb_t carry = -38;
+  for (i = 0; i < NLIMBS; i++) {
+    carry = carry + a[i] - b[i];
+    out[i] = (limb_t) carry;
+    carry >>= X25519_WBITS;
+  }
+  propagate(out, (limb_t) (1 + carry));
+}
+
+// `b` can contain less than 8 limbs, thus we use `limb_t *` instead of `mg_fe`
+// to avoid build warnings
+static void mul(mg_fe out, const mg_fe a, const limb_t *b, unsigned nb) {
+  limb_t accum[2 * NLIMBS] = {0};
+  unsigned i, j;
+
+  limb_t carry2;
+  for (i = 0; i < nb; i++) {
+    limb_t mand = b[i];
+    carry2 = 0;
+    for (j = 0; j < NLIMBS; j++) {
+      limb_t tmp;                        // "a" may be misaligned
+      memcpy(&tmp, &a[j], sizeof(tmp));  // So make an aligned copy
+      accum[i + j] = umaal(&carry2, accum[i + j], mand, tmp);
+    }
+    accum[i + j] = carry2;
+  }
+
+  carry2 = 0;
+  for (j = 0; j < NLIMBS; j++) {
+    out[j] = umaal(&carry2, accum[j], 38, accum[j + NLIMBS]);
+  }
+  propagate(out, carry2);
 }
 
-size_t mg_tls_pending(struct mg_connection *c) {
-  struct mg_tls *tls = (struct mg_tls *) c->tls;
-  return tls == NULL ? 0 : (size_t) SSL_pending(tls->ssl);
+static void sqr(mg_fe out, const mg_fe a) {
+  mul(out, a, a, NLIMBS);
+}
+static void mul1(mg_fe out, const mg_fe a) {
+  mul(out, a, out, NLIMBS);
+}
+static void sqr1(mg_fe a) {
+  mul1(a, a);
 }
 
-long mg_tls_recv(struct mg_connection *c, void *buf, size_t len) {
-  struct mg_tls *tls = (struct mg_tls *) c->tls;
-  int n = SSL_read(tls->ssl, buf, (int) len);
-  if (n < 0 && mg_tls_err(tls, n) == 0) return MG_IO_WAIT;
-  if (n <= 0) return MG_IO_ERR;
-  return n;
+static void condswap(limb_t a[2 * NLIMBS], limb_t b[2 * NLIMBS],
+                     limb_t doswap) {
+  unsigned i;
+  for (i = 0; i < 2 * NLIMBS; i++) {
+    limb_t xor_ab = (a[i] ^ b[i]) & doswap;
+    a[i] ^= xor_ab;
+    b[i] ^= xor_ab;
+  }
 }
 
-long mg_tls_send(struct mg_connection *c, const void *buf, size_t len) {
-  struct mg_tls *tls = (struct mg_tls *) c->tls;
-  int n = SSL_write(tls->ssl, buf, (int) len);
-  if (n < 0 && mg_tls_err(tls, n) == 0) return MG_IO_WAIT;
-  if (n <= 0) return MG_IO_ERR;
-  return n;
+// Canonicalize a field element x, reducing it to the least residue which is
+// congruent to it mod 2^255-19
+// - Precondition: x < 2^255 + 1 word
+static limb_t canon(mg_fe x) {
+  // First, add 19.
+  unsigned i;
+  limb_t carry0 = 19;
+  limb_t res;
+  sdlimb_t carry;
+  for (i = 0; i < NLIMBS; i++) {
+    x[i] = adc0(&carry0, x[i]);
+  }
+  propagate(x, carry0);
+
+  // Here, 19 <= x2 < 2^255
+  // - This is because we added 19, so before propagate it can't be less
+  // than 19. After propagate, it still can't be less than 19, because if
+  // propagate does anything it adds 19.
+  // - We know that the high bit must be clear, because either the input was ~
+  // 2^255 + one word + 19 (in which case it propagates to at most 2 words) or
+  // it was < 2^255. So now, if we subtract 19, we will get back to something in
+  // [0,2^255-19).
+  carry = -19;
+  res = 0;
+  for (i = 0; i < NLIMBS; i++) {
+    carry += x[i];
+    res |= x[i] = (limb_t) carry;
+    carry >>= X25519_WBITS;
+  }
+  return (limb_t) (((dlimb_t) res - 1) >> X25519_WBITS);
+}
+
+static const limb_t a24[1] = {121665};
+
+static void ladder_part1(mg_fe xs[5]) {
+  limb_t *x2 = xs[0], *z2 = xs[1], *x3 = xs[2], *z3 = xs[3], *t1 = xs[4];
+  add(t1, x2, z2);                                 // t1 = A
+  sub(z2, x2, z2);                                 // z2 = B
+  add(x2, x3, z3);                                 // x2 = C
+  sub(z3, x3, z3);                                 // z3 = D
+  mul1(z3, t1);                                    // z3 = DA
+  mul1(x2, z2);                                    // x3 = BC
+  add(x3, z3, x2);                                 // x3 = DA+CB
+  sub(z3, z3, x2);                                 // z3 = DA-CB
+  sqr1(t1);                                        // t1 = AA
+  sqr1(z2);                                        // z2 = BB
+  sub(x2, t1, z2);                                 // x2 = E = AA-BB
+  mul(z2, x2, a24, sizeof(a24) / sizeof(a24[0]));  // z2 = E*a24
+  add(z2, z2, t1);                                 // z2 = E*a24 + AA
+}
+
+static void ladder_part2(mg_fe xs[5], const mg_fe x1) {
+  limb_t *x2 = xs[0], *z2 = xs[1], *x3 = xs[2], *z3 = xs[3], *t1 = xs[4];
+  sqr1(z3);         // z3 = (DA-CB)^2
+  mul1(z3, x1);     // z3 = x1 * (DA-CB)^2
+  sqr1(x3);         // x3 = (DA+CB)^2
+  mul1(z2, x2);     // z2 = AA*(E*a24+AA)
+  sub(x2, t1, x2);  // x2 = BB again
+  mul1(x2, t1);     // x2 = AA*BB
+}
+
+static void x25519_core(mg_fe xs[5], const uint8_t scalar[X25519_BYTES],
+                        const uint8_t *x1, int clamp) {
+  int i;
+  mg_fe x1_limbs;
+  limb_t swap = 0;
+  limb_t *x2 = xs[0], *x3 = xs[2], *z3 = xs[3];
+  memset(xs, 0, 4 * sizeof(mg_fe));
+  x2[0] = z3[0] = 1;
+  for (i = 0; i < NLIMBS; i++) {
+    x3[i] = x1_limbs[i] =
+        MG_U32(x1[i * 4 + 3], x1[i * 4 + 2], x1[i * 4 + 1], x1[i * 4]);
+  }
+
+  for (i = 255; i >= 0; i--) {
+    uint8_t bytei = scalar[i / 8];
+    limb_t doswap;
+    if (clamp) {
+      if (i / 8 == 0) {
+        bytei &= (uint8_t) ~7U;
+      } else if (i / 8 == X25519_BYTES - 1) {
+        bytei &= 0x7F;
+        bytei |= 0x40;
+      }
+    }
+    doswap = 0 - (limb_t) ((bytei >> (i % 8)) & 1);
+    condswap(x2, x3, swap ^ doswap);
+    swap = doswap;
+
+    ladder_part1(xs);
+    ladder_part2(xs, (const limb_t *) x1_limbs);
+  }
+  condswap(x2, x3, swap);
+}
+
+int mg_tls_x25519(uint8_t out[X25519_BYTES], const uint8_t scalar[X25519_BYTES],
+                  const uint8_t x1[X25519_BYTES], int clamp) {
+  int i, ret;
+  mg_fe xs[5], out_limbs;
+  limb_t *x2, *z2, *z3, *prev;
+  static const struct {
+    uint8_t a, c, n;
+  } steps[13] = {{2, 1, 1},  {2, 1, 1},  {4, 2, 3},  {2, 4, 6},  {3, 1, 1},
+                 {3, 2, 12}, {4, 3, 25}, {2, 3, 25}, {2, 4, 50}, {3, 2, 125},
+                 {3, 1, 2},  {3, 1, 2},  {3, 1, 1}};
+  x25519_core(xs, scalar, x1, clamp);
+
+  // Precomputed inversion chain
+  x2 = xs[0];
+  z2 = xs[1];
+  z3 = xs[3];
+
+  prev = z2;
+  for (i = 0; i < 13; i++) {
+    int j;
+    limb_t *a = xs[steps[i].a];
+    for (j = steps[i].n; j > 0; j--) {
+      sqr(a, prev);
+      prev = a;
+    }
+    mul1(a, xs[steps[i].c]);
+  }
+
+  // Here prev = z3
+  // x2 /= z2
+  mul(out_limbs, x2, z3, NLIMBS);
+  ret = (int) canon(out_limbs);
+  if (!clamp) ret = 0;
+  for (i = 0; i < NLIMBS; i++) {
+    uint32_t n = out_limbs[i];
+    out[i * 4] = (uint8_t) (n & 0xff);
+    out[i * 4 + 1] = (uint8_t) ((n >> 8) & 0xff);
+    out[i * 4 + 2] = (uint8_t) ((n >> 16) & 0xff);
+    out[i * 4 + 3] = (uint8_t) ((n >> 24) & 0xff);
+  }
+  return ret;
 }
-#endif
 
 #ifdef MG_ENABLE_LINES
 #line 1 "src/url.c"
@@ -5382,7 +14797,7 @@ struct url {
 int mg_url_is_ssl(const char *url) {
   return strncmp(url, "wss:", 4) == 0 || strncmp(url, "https:", 6) == 0 ||
          strncmp(url, "mqtts:", 6) == 0 || strncmp(url, "ssl:", 4) == 0 ||
-         strncmp(url, "tls:", 4) == 0;
+         strncmp(url, "tls:", 4) == 0 || strncmp(url, "tcps:", 5) == 0;
 }
 
 static struct url urlparse(const char *url) {
@@ -5464,6 +14879,14 @@ struct mg_str mg_url_pass(const char *url) {
 #endif
 
 
+// Not using memset for zeroing memory, cause it can be dropped by compiler
+// See https://github.com/cesanta/mongoose/pull/1265
+void mg_bzero(volatile unsigned char *buf, size_t len) {
+  if (buf != NULL) {
+    while (len--) *buf++ = 0;
+  }
+}
+
 #if MG_ENABLE_CUSTOM_RANDOM
 #else
 void mg_random(void *buf, size_t len) {
@@ -5512,11 +14935,16 @@ uint16_t mg_ntohs(uint16_t net) {
 }
 
 uint32_t mg_crc32(uint32_t crc, const char *buf, size_t len) {
-  int i;
+  static const uint32_t crclut[16] = {
+      // table for polynomial 0xEDB88320 (reflected)
+      0x00000000, 0x1DB71064, 0x3B6E20C8, 0x26D930AC, 0x76DC4190, 0x6B6B51F4,
+      0x4DB26158, 0x5005713C, 0xEDB88320, 0xF00F9344, 0xD6D6A3E8, 0xCB61B38C,
+      0x9B64C2B0, 0x86D3D2D4, 0xA00AE278, 0xBDBDF21C};
   crc = ~crc;
   while (len--) {
-    crc ^= *(unsigned char *) buf++;
-    for (i = 0; i < 8; i++) crc = crc & 1 ? (crc >> 1) ^ 0xedb88320 : crc >> 1;
+    uint8_t b = *(uint8_t *) buf++;
+    crc = crclut[(crc ^ b) & 0x0F] ^ (crc >> 4);
+    crc = crclut[(crc ^ (b >> 4)) & 0x0F] ^ (crc >> 4);
   }
   return ~crc;
 }
@@ -5539,18 +14967,36 @@ static int parse_net(const char *spec, uint32_t *net, uint32_t *mask) {
   return len;
 }
 
-int mg_check_ip_acl(struct mg_str acl, uint32_t remote_ip) {
-  struct mg_str k, v;
+int mg_check_ip_acl(struct mg_str acl, struct mg_addr *remote_ip) {
+  struct mg_str entry;
   int allowed = acl.len == 0 ? '+' : '-';  // If any ACL is set, deny by default
-  while (mg_commalist(&acl, &k, &v)) {
-    uint32_t net, mask;
-    if (k.ptr[0] != '+' && k.ptr[0] != '-') return -1;
-    if (parse_net(&k.ptr[1], &net, &mask) == 0) return -2;
-    if ((mg_ntohl(remote_ip) & mask) == net) allowed = k.ptr[0];
+  uint32_t remote_ip4;
+  if (remote_ip->is_ip6) {
+    return -1;  // TODO(): handle IPv6 ACL and addresses
+  } else {      // IPv4
+    memcpy((void *) &remote_ip4, remote_ip->ip, sizeof(remote_ip4));
+    while (mg_span(acl, &entry, &acl, ',')) {
+      uint32_t net, mask;
+      if (entry.buf[0] != '+' && entry.buf[0] != '-') return -1;
+      if (parse_net(&entry.buf[1], &net, &mask) == 0) return -2;
+      if ((mg_ntohl(remote_ip4) & mask) == net) allowed = entry.buf[0];
+    }
   }
   return allowed == '+';
 }
 
+bool mg_path_is_sane(const struct mg_str path) {
+  const char *s = path.buf;
+  size_t n = path.len;
+  if (path.buf[0] == '.' && path.buf[1] == '.') return false;  // Starts with ..
+  for (; s[0] != '\0' && n > 0; s++, n--) {
+    if ((s[0] == '/' || s[0] == '\\') && n >= 2) {   // Subdir?
+      if (s[1] == '.' && s[2] == '.') return false;  // Starts with ..
+    }
+  }
+  return true;
+}
+
 #if MG_ENABLE_CUSTOM_MILLIS
 #else
 uint64_t mg_millis(void) {
@@ -5558,9 +15004,8 @@ uint64_t mg_millis(void) {
   return GetTickCount();
 #elif MG_ARCH == MG_ARCH_RP2040
   return time_us_64() / 1000;
-#elif MG_ARCH == MG_ARCH_ESP32
-  return esp_timer_get_time() / 1000;
-#elif MG_ARCH == MG_ARCH_ESP8266 || MG_ARCH == MG_ARCH_FREERTOS
+#elif MG_ARCH == MG_ARCH_ESP8266 || MG_ARCH == MG_ARCH_ESP32 || \
+    MG_ARCH == MG_ARCH_FREERTOS
   return xTaskGetTickCount() * portTICK_PERIOD_MS;
 #elif MG_ARCH == MG_ARCH_AZURERTOS
   return tx_time_get() * (1000 /* MS per SEC */ / TX_TIMER_TICKS_PER_SECOND);
@@ -5568,6 +15013,12 @@ uint64_t mg_millis(void) {
   return (uint64_t) Clock_getTicks();
 #elif MG_ARCH == MG_ARCH_ZEPHYR
   return (uint64_t) k_uptime_get();
+#elif MG_ARCH == MG_ARCH_CMSIS_RTOS1
+  return (uint64_t) rt_time_get();
+#elif MG_ARCH == MG_ARCH_CMSIS_RTOS2
+  return (uint64_t) ((osKernelGetTickCount() * 1000) / osKernelGetTickFreq());
+#elif MG_ARCH == MG_ARCH_RTTHREAD
+  return (uint64_t) ((rt_tick_get() * 1000) / RT_TICK_PER_SECOND);
 #elif MG_ARCH == MG_ARCH_UNIX && defined(__APPLE__)
   // Apple CLOCK_MONOTONIC_RAW is equivalent to CLOCK_BOOTTIME on linux
   // Apple CLOCK_UPTIME_RAW is equivalent to CLOCK_MONOTONIC_RAW on linux
@@ -5595,7 +15046,6 @@ uint64_t mg_millis(void) {
 }
 #endif
 
-
 #ifdef MG_ENABLE_LINES
 #line 1 "src/ws.c"
 #endif
@@ -5609,6 +15059,7 @@ uint64_t mg_millis(void) {
 
 
 
+
 struct ws_msg {
   uint8_t flags;
   size_t header_len;
@@ -5640,10 +15091,10 @@ static void ws_handshake(struct mg_connection *c, const struct mg_str *wskey,
 
   mg_sha1_ctx sha_ctx;
   mg_sha1_init(&sha_ctx);
-  mg_sha1_update(&sha_ctx, (unsigned char *) wskey->ptr, wskey->len);
+  mg_sha1_update(&sha_ctx, (unsigned char *) wskey->buf, wskey->len);
   mg_sha1_update(&sha_ctx, (unsigned char *) magic, 36);
   mg_sha1_final(sha, &sha_ctx);
-  mg_base64_encode(sha, sizeof(sha), (char *) b64_sha);
+  mg_base64_encode(sha, sizeof(sha), (char *) b64_sha, sizeof(b64_sha));
   mg_xprintf(mg_pfn_iobuf, &c->send,
              "HTTP/1.1 101 Switching Protocols\r\n"
              "Upgrade: websocket\r\n"
@@ -5653,7 +15104,7 @@ static void ws_handshake(struct mg_connection *c, const struct mg_str *wskey,
   if (fmt != NULL) mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, ap);
   if (wsproto != NULL) {
     mg_printf(c, "Sec-WebSocket-Protocol: %.*s\r\n", (int) wsproto->len,
-              wsproto->ptr);
+              wsproto->buf);
   }
   mg_send(c, "\r\n", 2);
 }
@@ -5746,12 +15197,15 @@ static bool mg_ws_client_handshake(struct mg_connection *c) {
     mg_error(c, "not http");  // Some just, not an HTTP request
   } else if (n > 0) {
     if (n < 15 || memcmp(c->recv.buf + 9, "101", 3) != 0) {
-      mg_error(c, "handshake error");
+      mg_error(c, "ws handshake error");
     } else {
       struct mg_http_message hm;
-      mg_http_parse((char *) c->recv.buf, c->recv.len, &hm);
-      c->is_websocket = 1;
-      mg_call(c, MG_EV_WS_OPEN, &hm);
+      if (mg_http_parse((char *) c->recv.buf, c->recv.len, &hm)) {
+        c->is_websocket = 1;
+        mg_call(c, MG_EV_WS_OPEN, &hm);
+      } else {
+        mg_error(c, "ws handshake error");
+      }
     }
     mg_iobuf_del(&c->recv, 0, (size_t) n);
   } else {
@@ -5760,8 +15214,7 @@ static bool mg_ws_client_handshake(struct mg_connection *c) {
   return false;  // Continue event handler
 }
 
-static void mg_ws_cb(struct mg_connection *c, int ev, void *ev_data,
-                     void *fn_data) {
+static void mg_ws_cb(struct mg_connection *c, int ev, void *ev_data) {
   struct ws_msg msg;
   size_t ofs = (size_t) c->pfn_data;
 
@@ -5775,7 +15228,7 @@ static void mg_ws_cb(struct mg_connection *c, int ev, void *ev_data,
       size_t len = msg.header_len + msg.data_len;
       uint8_t final = msg.flags & 128, op = msg.flags & 15;
       // MG_VERBOSE ("fin %d op %d len %d [%.*s]", final, op,
-      //                       (int) m.data.len, (int) m.data.len, m.data.ptr));
+      //                       (int) m.data.len, (int) m.data.len, m.data.buf));
       switch (op) {
         case WEBSOCKET_OP_CONTINUE:
           mg_call(c, MG_EV_WS_CTL, &m);
@@ -5796,7 +15249,7 @@ static void mg_ws_cb(struct mg_connection *c, int ev, void *ev_data,
           MG_DEBUG(("%lu WS CLOSE", c->id));
           mg_call(c, MG_EV_WS_CTL, &m);
           // Echo the payload of the received CLOSE message back to the sender
-          mg_ws_send(c, m.data.ptr, m.data.len, WEBSOCKET_OP_CLOSE);
+          mg_ws_send(c, m.data.buf, m.data.len, WEBSOCKET_OP_CLOSE);
           c->is_draining = 1;
           break;
         default:
@@ -5827,7 +15280,6 @@ static void mg_ws_cb(struct mg_connection *c, int ev, void *ev_data,
       }
     }
   }
-  (void) fn_data;
   (void) ev_data;
 }
 
@@ -5839,7 +15291,7 @@ struct mg_connection *mg_ws_connect(struct mg_mgr *mgr, const char *url,
     char nonce[16], key[30];
     struct mg_str host = mg_url_host(url);
     mg_random(nonce, sizeof(nonce));
-    mg_base64_encode((unsigned char *) nonce, sizeof(nonce), key);
+    mg_base64_encode((unsigned char *) nonce, sizeof(nonce), key, sizeof(key));
     mg_xprintf(mg_pfn_iobuf, &c->send,
                "GET %s HTTP/1.1\r\n"
                "Upgrade: websocket\r\n"
@@ -5847,7 +15299,7 @@ struct mg_connection *mg_ws_connect(struct mg_mgr *mgr, const char *url,
                "Connection: Upgrade\r\n"
                "Sec-WebSocket-Version: 13\r\n"
                "Sec-WebSocket-Key: %s\r\n",
-               mg_url_uri(url), (int) host.len, host.ptr, key);
+               mg_url_uri(url), (int) host.len, host.buf, key);
     if (fmt != NULL) {
       va_list ap;
       va_start(ap, fmt);
@@ -5896,1591 +15348,2247 @@ size_t mg_ws_wrap(struct mg_connection *c, size_t len, int op) {
 }
 
 #ifdef MG_ENABLE_LINES
-#line 1 "mip/driver_stm32.c"
+#line 1 "src/drivers/cmsis.c"
 #endif
+// https://arm-software.github.io/CMSIS_5/Driver/html/index.html
 
+#if MG_ENABLE_TCPIP && defined(MG_ENABLE_DRIVER_CMSIS) && MG_ENABLE_DRIVER_CMSIS
 
-#if MG_ENABLE_MIP && \
-    (!defined(MG_ENABLE_DRIVER_TM4C) || MG_ENABLE_DRIVER_TM4C == 0)
-struct stm32_eth {
-  volatile uint32_t MACCR, MACFFR, MACHTHR, MACHTLR, MACMIIAR, MACMIIDR, MACFCR,
-      MACVLANTR, RESERVED0[2], MACRWUFFR, MACPMTCSR, RESERVED1, MACDBGR, MACSR,
-      MACIMR, MACA0HR, MACA0LR, MACA1HR, MACA1LR, MACA2HR, MACA2LR, MACA3HR,
-      MACA3LR, RESERVED2[40], MMCCR, MMCRIR, MMCTIR, MMCRIMR, MMCTIMR,
-      RESERVED3[14], MMCTGFSCCR, MMCTGFMSCCR, RESERVED4[5], MMCTGFCR,
-      RESERVED5[10], MMCRFCECR, MMCRFAECR, RESERVED6[10], MMCRGUFCR,
-      RESERVED7[334], PTPTSCR, PTPSSIR, PTPTSHR, PTPTSLR, PTPTSHUR, PTPTSLUR,
-      PTPTSAR, PTPTTHR, PTPTTLR, RESERVED8, PTPTSSR, PTPPPSCR, RESERVED9[564],
-      DMABMR, DMATPDR, DMARPDR, DMARDLAR, DMATDLAR, DMASR, DMAOMR, DMAIER,
-      DMAMFBOCR, DMARSWTR, RESERVED10[8], DMACHTDR, DMACHRDR, DMACHTBAR,
-      DMACHRBAR;
-};
-#undef ETH
-#define ETH ((struct stm32_eth *) (uintptr_t) 0x40028000)
 
-#undef BIT
-#define BIT(x) ((uint32_t) 1 << (x))
-#define ETH_PKT_SIZE 1540  // Max frame size
-#define ETH_DESC_CNT 4     // Descriptors count
-#define ETH_DS 4           // Descriptor size (words)
 
-static uint32_t s_rxdesc[ETH_DESC_CNT][ETH_DS];      // RX descriptors
-static uint32_t s_txdesc[ETH_DESC_CNT][ETH_DS];      // TX descriptors
-static uint8_t s_rxbuf[ETH_DESC_CNT][ETH_PKT_SIZE];  // RX ethernet buffers
-static uint8_t s_txbuf[ETH_DESC_CNT][ETH_PKT_SIZE];  // TX ethernet buffers
-static struct mip_if *s_ifp;                         // MIP interface
-enum { PHY_ADDR = 0, PHY_BCR = 0, PHY_BSR = 1 };     // PHY constants
 
-static uint32_t eth_read_phy(uint8_t addr, uint8_t reg) {
-  ETH->MACMIIAR &= (7 << 2);
-  ETH->MACMIIAR |= ((uint32_t) addr << 11) | ((uint32_t) reg << 6);
-  ETH->MACMIIAR |= BIT(0);
-  while (ETH->MACMIIAR & BIT(0)) (void) 0;
-  return ETH->MACMIIDR;
-}
 
-static void eth_write_phy(uint8_t addr, uint8_t reg, uint32_t val) {
-  ETH->MACMIIDR = val;
-  ETH->MACMIIAR &= (7 << 2);
-  ETH->MACMIIAR |= ((uint32_t) addr << 11) | ((uint32_t) reg << 6) | BIT(1);
-  ETH->MACMIIAR |= BIT(0);
-  while (ETH->MACMIIAR & BIT(0)) (void) 0;
-}
+extern ARM_DRIVER_ETH_MAC Driver_ETH_MAC0;
+extern ARM_DRIVER_ETH_PHY Driver_ETH_PHY0;
 
-static uint32_t get_hclk(void) {
-  struct rcc {
-    volatile uint32_t CR, PLLCFGR, CFGR;
-  } *rcc = (struct rcc *) 0x40023800;
-  uint32_t clk = 0, hsi = 16000000 /* 16 MHz */, hse = 8000000 /* 8MHz */;
+static struct mg_tcpip_if *s_ifp;
 
-  if (rcc->CFGR & (1 << 2)) {
-    clk = hse;
-  } else if (rcc->CFGR & (1 << 3)) {
-    uint32_t vco, m, n, p;
-    m = (rcc->PLLCFGR & (0x3f << 0)) >> 0;
-    n = (rcc->PLLCFGR & (0x1ff << 6)) >> 6;
-    p = (((rcc->PLLCFGR & (3 << 16)) >> 16) + 1) * 2;
-    clk = (rcc->PLLCFGR & (1 << 22)) ? hse : hsi;
-    vco = (uint32_t) ((uint64_t) clk * n / m);
-    clk = vco / p;
-  } else {
-    clk = hsi;
+static void mac_cb(uint32_t);
+static bool cmsis_init(struct mg_tcpip_if *);
+static bool cmsis_up(struct mg_tcpip_if *);
+static size_t cmsis_tx(const void *, size_t, struct mg_tcpip_if *);
+static size_t cmsis_rx(void *, size_t, struct mg_tcpip_if *);
+
+struct mg_tcpip_driver mg_tcpip_driver_cmsis = {cmsis_init, cmsis_tx, NULL,
+                                                cmsis_up};
+
+static bool cmsis_init(struct mg_tcpip_if *ifp) {
+  ARM_ETH_MAC_ADDR addr;
+  s_ifp = ifp;
+
+  ARM_DRIVER_ETH_MAC *mac = &Driver_ETH_MAC0;
+  ARM_DRIVER_ETH_PHY *phy = &Driver_ETH_PHY0;
+  ARM_ETH_MAC_CAPABILITIES cap = mac->GetCapabilities();
+  if (mac->Initialize(mac_cb) != ARM_DRIVER_OK) return false;
+  if (phy->Initialize(mac->PHY_Read, mac->PHY_Write) != ARM_DRIVER_OK)
+    return false;
+  if (cap.event_rx_frame == 0)  // polled mode driver
+    mg_tcpip_driver_cmsis.rx = cmsis_rx;
+  mac->PowerControl(ARM_POWER_FULL);
+  if (cap.mac_address) {  // driver provides MAC address
+    mac->GetMacAddress(&addr);
+    memcpy(ifp->mac, &addr, sizeof(ifp->mac));
+  } else {  // we provide MAC address
+    memcpy(&addr, ifp->mac, sizeof(addr));
+    mac->SetMacAddress(&addr);
   }
-  uint32_t hpre = (rcc->CFGR & (15 << 4)) >> 4;
-  if (hpre < 8) return clk;
+  phy->PowerControl(ARM_POWER_FULL);
+  phy->SetInterface(cap.media_interface);
+  phy->SetMode(ARM_ETH_PHY_AUTO_NEGOTIATE);
+  return true;
+}
 
-  uint8_t ahbptab[8] = {1, 2, 3, 4, 6, 7, 8, 9};  // log2(div)
-  return ((uint32_t) clk) >> ahbptab[hpre - 8];
+static size_t cmsis_tx(const void *buf, size_t len, struct mg_tcpip_if *ifp) {
+  ARM_DRIVER_ETH_MAC *mac = &Driver_ETH_MAC0;
+  if (mac->SendFrame(buf, (uint32_t) len, 0) != ARM_DRIVER_OK) {
+    ifp->nerr++;
+    return 0;
+  }
+  ifp->nsent++;
+  return len;
 }
 
-//  Guess CR from HCLK. MDC clock is generated from HCLK (AHB); as per 802.3,
-//  it must not exceed 2.5MHz As the AHB clock can be (and usually is) derived
-//  from the HSI (internal RC), and it can go above specs, the datasheets
-//  specify a range of frequencies and activate one of a series of dividers to
-//  keep the MDC clock safely below 2.5MHz. We guess a divider setting based on
-//  HCLK with a +5% drift. If the user uses a different clock from our
-//  defaults, needs to set the macros on top Valid for STM32F74xxx/75xxx
-//  (38.8.1) and STM32F42xxx/43xxx (33.8.1) (both 4.5% worst case drift)
-static int guess_mdc_cr(void) {
-  uint8_t crs[] = {2, 3, 0, 1, 4, 5};          // ETH->MACMIIAR::CR values
-  uint8_t div[] = {16, 26, 42, 62, 102, 124};  // Respective HCLK dividers
-  uint32_t hclk = get_hclk();                  // Guess system HCLK
-  int result = -1;                             // Invalid CR value
-  if (hclk < 25000000) {
-    MG_ERROR(("HCLK too low"));
-  } else {
-    for (int i = 0; i < 6; i++) {
-      if (hclk / div[i] <= 2375000UL /* 2.5MHz - 5% */) {
-        result = crs[i];
-        break;
+static bool cmsis_up(struct mg_tcpip_if *ifp) {
+  ARM_DRIVER_ETH_PHY *phy = &Driver_ETH_PHY0;
+  ARM_DRIVER_ETH_MAC *mac = &Driver_ETH_MAC0;
+  bool up = (phy->GetLinkState() == ARM_ETH_LINK_UP) ? 1 : 0;  // link state
+  if ((ifp->state == MG_TCPIP_STATE_DOWN) && up) {             // just went up
+    ARM_ETH_LINK_INFO st = phy->GetLinkInfo();
+    mac->Control(ARM_ETH_MAC_CONFIGURE,
+                 (st.speed << ARM_ETH_MAC_SPEED_Pos) |
+                     (st.duplex << ARM_ETH_MAC_DUPLEX_Pos) |
+                     ARM_ETH_MAC_ADDRESS_BROADCAST);
+    MG_DEBUG(("Link is %uM %s-duplex",
+              (st.speed == 2) ? 1000
+              : st.speed      ? 100
+                              : 10,
+              st.duplex ? "full" : "half"));
+    mac->Control(ARM_ETH_MAC_CONTROL_TX, 1);
+    mac->Control(ARM_ETH_MAC_CONTROL_RX, 1);
+  } else if ((ifp->state != MG_TCPIP_STATE_DOWN) && !up) {  // just went down
+    mac->Control(ARM_ETH_MAC_FLUSH,
+                 ARM_ETH_MAC_FLUSH_TX | ARM_ETH_MAC_FLUSH_RX);
+    mac->Control(ARM_ETH_MAC_CONTROL_TX, 0);
+    mac->Control(ARM_ETH_MAC_CONTROL_RX, 0);
+  }
+  return up;
+}
+
+static void mac_cb(uint32_t ev) {
+  if ((ev & ARM_ETH_MAC_EVENT_RX_FRAME) == 0) return;
+  ARM_DRIVER_ETH_MAC *mac = &Driver_ETH_MAC0;
+  uint32_t len = mac->GetRxFrameSize();  // CRC already stripped
+  if (len >= 60 && len <= 1518) {        // proper frame
+    char *p;
+    if (mg_queue_book(&s_ifp->recv_queue, &p, len) >= len) {  // have room
+      if ((len = mac->ReadFrame((uint8_t *) p, len)) > 0) {   // copy succeeds
+        mg_queue_add(&s_ifp->recv_queue, len);
+        s_ifp->nrecv++;
       }
+      return;
     }
-    if (result < 0) MG_ERROR(("HCLK too high"));
+    s_ifp->ndrop++;
   }
-  MG_DEBUG(("HCLK: %u, CR: %d", hclk, result));
-  return result;
+  mac->ReadFrame(NULL, 0);  // otherwise, discard
+}
+
+static size_t cmsis_rx(void *buf, size_t buflen, struct mg_tcpip_if *ifp) {
+  ARM_DRIVER_ETH_MAC *mac = &Driver_ETH_MAC0;
+  uint32_t len = mac->GetRxFrameSize();  // CRC already stripped
+  if (len >= 60 && len <= 1518 &&
+      ((len = mac->ReadFrame(buf, (uint32_t) buflen)) > 0))
+    return len;
+  if (len > 0) mac->ReadFrame(NULL, 0);  // discard bad frames
+  (void) ifp;
+  return 0;
 }
 
-static bool mip_driver_stm32_init(struct mip_if *ifp) {
-  struct mip_driver_stm32_data *d = (struct mip_driver_stm32_data *) ifp->driver_data;
+#endif
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/drivers/imxrt.c"
+#endif
+
+
+#if MG_ENABLE_TCPIP && defined(MG_ENABLE_DRIVER_IMXRT) && MG_ENABLE_DRIVER_IMXRT
+struct imxrt_enet {
+  volatile uint32_t RESERVED0, EIR, EIMR, RESERVED1, RDAR, TDAR, RESERVED2[3],
+      ECR, RESERVED3[6], MMFR, MSCR, RESERVED4[7], MIBC, RESERVED5[7], RCR,
+      RESERVED6[15], TCR, RESERVED7[7], PALR, PAUR, OPD, TXIC0, TXIC1, TXIC2,
+      RESERVED8, RXIC0, RXIC1, RXIC2, RESERVED9[3], IAUR, IALR, GAUR, GALR,
+      RESERVED10[7], TFWR, RESERVED11[14], RDSR, TDSR, MRBR[2], RSFL, RSEM,
+      RAEM, RAFL, TSEM, TAEM, TAFL, TIPG, FTRL, RESERVED12[3], TACC, RACC,
+      RESERVED13[15], RMON_T_PACKETS, RMON_T_BC_PKT, RMON_T_MC_PKT,
+      RMON_T_CRC_ALIGN, RMON_T_UNDERSIZE, RMON_T_OVERSIZE, RMON_T_FRAG,
+      RMON_T_JAB, RMON_T_COL, RMON_T_P64, RMON_T_P65TO127, RMON_T_P128TO255,
+      RMON_T_P256TO511, RMON_T_P512TO1023, RMON_T_P1024TO2048, RMON_T_GTE2048,
+      RMON_T_OCTETS, IEEE_T_DROP, IEEE_T_FRAME_OK, IEEE_T_1COL, IEEE_T_MCOL,
+      IEEE_T_DEF, IEEE_T_LCOL, IEEE_T_EXCOL, IEEE_T_MACERR, IEEE_T_CSERR,
+      IEEE_T_SQE, IEEE_T_FDXFC, IEEE_T_OCTETS_OK, RESERVED14[3], RMON_R_PACKETS,
+      RMON_R_BC_PKT, RMON_R_MC_PKT, RMON_R_CRC_ALIGN, RMON_R_UNDERSIZE,
+      RMON_R_OVERSIZE, RMON_R_FRAG, RMON_R_JAB, RESERVED15, RMON_R_P64,
+      RMON_R_P65TO127, RMON_R_P128TO255, RMON_R_P256TO511, RMON_R_P512TO1023,
+      RMON_R_P1024TO2047, RMON_R_GTE2048, RMON_R_OCTETS, IEEE_R_DROP,
+      IEEE_R_FRAME_OK, IEEE_R_CRC, IEEE_R_ALIGN, IEEE_R_MACERR, IEEE_R_FDXFC,
+      IEEE_R_OCTETS_OK, RESERVED16[71], ATCR, ATVR, ATOFF, ATPER, ATCOR, ATINC,
+      ATSTMP, RESERVED17[122], TGSR, TCSR0, TCCR0, TCSR1, TCCR1, TCSR2, TCCR2,
+      TCSR3;
+};
+
+#undef ENET
+#if defined(MG_DRIVER_IMXRT_RT11) && MG_DRIVER_IMXRT_RT11
+#define ENET ((struct imxrt_enet *) (uintptr_t) 0x40424000U)
+#define ETH_DESC_CNT 5     // Descriptors count
+#else
+#define ENET ((struct imxrt_enet *) (uintptr_t) 0x402D8000U)
+#define ETH_DESC_CNT 4     // Descriptors count
+#endif
+
+#define ETH_PKT_SIZE 1536  // Max frame size, 64-bit aligned
+
+struct enet_desc {
+  uint16_t length;   // Data length
+  uint16_t control;  // Control and status
+  uint32_t *buffer;  // Data ptr
+};
+
+// TODO(): handle these in a portable compiler-independent CMSIS-friendly way
+#define MG_64BYTE_ALIGNED __attribute__((aligned((64U))))
+
+// Descriptors: in non-cached area (TODO(scaprile)), (37.5.1.22.2 37.5.1.23.2)
+// Buffers: 64-byte aligned (37.3.14)
+static volatile struct enet_desc s_rxdesc[ETH_DESC_CNT] MG_64BYTE_ALIGNED;
+static volatile struct enet_desc s_txdesc[ETH_DESC_CNT] MG_64BYTE_ALIGNED;
+static uint8_t s_rxbuf[ETH_DESC_CNT][ETH_PKT_SIZE] MG_64BYTE_ALIGNED;
+static uint8_t s_txbuf[ETH_DESC_CNT][ETH_PKT_SIZE] MG_64BYTE_ALIGNED;
+static struct mg_tcpip_if *s_ifp;  // MIP interface
+
+static uint16_t enet_read_phy(uint8_t addr, uint8_t reg) {
+  ENET->EIR |= MG_BIT(23);  // MII interrupt clear
+  ENET->MMFR = (1 << 30) | (2 << 28) | (addr << 23) | (reg << 18) | (2 << 16);
+  while ((ENET->EIR & MG_BIT(23)) == 0) (void) 0;
+  return ENET->MMFR & 0xffff;
+}
+
+static void enet_write_phy(uint8_t addr, uint8_t reg, uint16_t val) {
+  ENET->EIR |= MG_BIT(23);  // MII interrupt clear
+  ENET->MMFR =
+      (1 << 30) | (1 << 28) | (addr << 23) | (reg << 18) | (2 << 16) | val;
+  while ((ENET->EIR & MG_BIT(23)) == 0) (void) 0;
+}
+
+//  MDC clock is generated from IPS Bus clock (ipg_clk); as per 802.3,
+//  it must not exceed 2.5MHz
+// The PHY receives the PLL6-generated 50MHz clock
+static bool mg_tcpip_driver_imxrt_init(struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_driver_imxrt_data *d =
+      (struct mg_tcpip_driver_imxrt_data *) ifp->driver_data;
   s_ifp = ifp;
 
   // Init RX descriptors
   for (int i = 0; i < ETH_DESC_CNT; i++) {
-    s_rxdesc[i][0] = BIT(31);                            // Own
-    s_rxdesc[i][1] = sizeof(s_rxbuf[i]) | BIT(14);       // 2nd address chained
-    s_rxdesc[i][2] = (uint32_t) (uintptr_t) s_rxbuf[i];  // Point to data buffer
-    s_rxdesc[i][3] =
-        (uint32_t) (uintptr_t) s_rxdesc[(i + 1) % ETH_DESC_CNT];  // Chain
+    s_rxdesc[i].control = MG_BIT(15);              // Own (E)
+    s_rxdesc[i].buffer = (uint32_t *) s_rxbuf[i];  // Point to data buffer
   }
+  s_rxdesc[ETH_DESC_CNT - 1].control |= MG_BIT(13);  // Wrap last descriptor
 
   // Init TX descriptors
   for (int i = 0; i < ETH_DESC_CNT; i++) {
-    s_txdesc[i][2] = (uint32_t) (uintptr_t) s_txbuf[i];  // Buf pointer
-    s_txdesc[i][3] =
-        (uint32_t) (uintptr_t) s_txdesc[(i + 1) % ETH_DESC_CNT];  // Chain
+    // s_txdesc[i].control = MG_BIT(10);  // Own (TC)
+    s_txdesc[i].buffer = (uint32_t *) s_txbuf[i];
   }
-
-  ETH->DMABMR |= BIT(0);                         // Software reset
-  while ((ETH->DMABMR & BIT(0)) != 0) (void) 0;  // Wait until done
-
-  // Set MDC clock divider. If user told us the value, use it. Otherwise, guess
-  int cr = (d == NULL || d->mdc_cr < 0) ? guess_mdc_cr() : d->mdc_cr;
-  ETH->MACMIIAR = ((uint32_t) cr & 7) << 2;
-
-  // NOTE(cpq): we do not use extended descriptor bit 7, and do not use
-  // hardware checksum. Therefore, descriptor size is 4, not 8
-  // ETH->DMABMR = BIT(13) | BIT(16) | BIT(22) | BIT(23) | BIT(25);
-  ETH->MACIMR = BIT(3) | BIT(9);  // Mask timestamp & PMT IT
-  ETH->MACFCR = BIT(7);           // Disable zero quarta pause
-  // ETH->MACFFR = BIT(31);                            // Receive all
-  eth_write_phy(PHY_ADDR, PHY_BCR, BIT(15));           // Reset PHY
-  eth_write_phy(PHY_ADDR, PHY_BCR, BIT(12));           // Set autonegotiation
-  ETH->DMARDLAR = (uint32_t) (uintptr_t) s_rxdesc;     // RX descriptors
-  ETH->DMATDLAR = (uint32_t) (uintptr_t) s_txdesc;     // RX descriptors
-  ETH->DMAIER = BIT(6) | BIT(16);                      // RIE, NISE
-  ETH->MACCR = BIT(2) | BIT(3) | BIT(11) | BIT(14);    // RE, TE, Duplex, Fast
-  ETH->DMAOMR = BIT(1) | BIT(13) | BIT(21) | BIT(25);  // SR, ST, TSF, RSF
-
-  // MAC address filtering
-  ETH->MACA0HR = ((uint32_t) ifp->mac[5] << 8U) | ifp->mac[4];
-  ETH->MACA0LR = (uint32_t) (ifp->mac[3] << 24) |
-                 ((uint32_t) ifp->mac[2] << 16) |
-                 ((uint32_t) ifp->mac[1] << 8) | ifp->mac[0];
-  if (ifp->queue.len == 0) ifp->queue.len = 8192;
+  s_txdesc[ETH_DESC_CNT - 1].control |= MG_BIT(13);  // Wrap last descriptor
+
+  ENET->ECR = MG_BIT(0);                     // Software reset, disable
+  while ((ENET->ECR & MG_BIT(0))) (void) 0;  // Wait until done
+
+  // Set MDC clock divider. If user told us the value, use it.
+  // TODO(): Otherwise, guess (currently assuming max freq)
+  int cr = (d == NULL || d->mdc_cr < 0) ? 24 : d->mdc_cr;
+  ENET->MSCR = (1 << 8) | ((cr & 0x3f) << 1);  // HOLDTIME 2 clks
+  struct mg_phy phy = {enet_read_phy, enet_write_phy};
+  mg_phy_init(&phy, d->phy_addr, MG_PHY_LEDS_ACTIVE_HIGH); // MAC clocks PHY  
+  // Select RMII mode, 100M, keep CRC, set max rx length, disable loop
+  ENET->RCR = (1518 << 16) | MG_BIT(8) | MG_BIT(2);
+  // ENET->RCR |= MG_BIT(3);     // Receive all
+  ENET->TCR = MG_BIT(2);  // Full-duplex
+  ENET->RDSR = (uint32_t) (uintptr_t) s_rxdesc;
+  ENET->TDSR = (uint32_t) (uintptr_t) s_txdesc;
+  ENET->MRBR[0] = ETH_PKT_SIZE;  // Same size for RX/TX buffers
+  // MAC address filtering (bytes in reversed order)
+  ENET->PAUR = ((uint32_t) ifp->mac[4] << 24U) | (uint32_t) ifp->mac[5] << 16U;
+  ENET->PALR = (uint32_t) (ifp->mac[0] << 24U) |
+               ((uint32_t) ifp->mac[1] << 16U) |
+               ((uint32_t) ifp->mac[2] << 8U) | ifp->mac[3];
+  ENET->ECR = MG_BIT(8) | MG_BIT(1);  // Little-endian CPU, Enable
+  ENET->EIMR = MG_BIT(25);            // Set interrupt mask
+  ENET->RDAR = MG_BIT(24);            // Receive Descriptors have changed
+  ENET->TDAR = MG_BIT(24);            // Transmit Descriptors have changed
+  // ENET->OPD = 0x10014;
   return true;
 }
 
-static uint32_t s_txno;
-static size_t mip_driver_stm32_tx(const void *buf, size_t len, struct mip_if *ifp) {
-  if (len > sizeof(s_txbuf[s_txno])) {
+// Transmit frame
+static size_t mg_tcpip_driver_imxrt_tx(const void *buf, size_t len,
+                                       struct mg_tcpip_if *ifp) {
+  static int s_txno;  // Current descriptor index
+  if (len > sizeof(s_txbuf[ETH_DESC_CNT])) {
     MG_ERROR(("Frame too big, %ld", (long) len));
-    len = 0;  // Frame is too big
-  } else if ((s_txdesc[s_txno][0] & BIT(31))) {
-    MG_ERROR(("No free descriptors"));
-    // printf("D0 %lx SR %lx\n", (long) s_txdesc[0][0], (long) ETH->DMASR);
-    len = 0;  // All descriptors are busy, fail
+    len = (size_t) -1;  // fail
+  } else if ((s_txdesc[s_txno].control & MG_BIT(15))) {
+    ifp->nerr++;
+    MG_ERROR(("No descriptors available"));
+    len = 0;  // retry later
   } else {
-    memcpy(s_txbuf[s_txno], buf, len);     // Copy data
-    s_txdesc[s_txno][1] = (uint32_t) len;  // Set data len
-    s_txdesc[s_txno][0] = BIT(20) | BIT(28) | BIT(29) | BIT(30);  // Chain,FS,LS
-    s_txdesc[s_txno][0] |= BIT(31);  // Set OWN bit - let DMA take over
+    memcpy(s_txbuf[s_txno], buf, len);         // Copy data
+    s_txdesc[s_txno].length = (uint16_t) len;  // Set data len
+    // Table 37-34, R, L, TC (Ready, last, transmit CRC after frame
+    s_txdesc[s_txno].control |=
+        (uint16_t) (MG_BIT(15) | MG_BIT(11) | MG_BIT(10));
+    ENET->TDAR = MG_BIT(24);  // Descriptor ring updated
     if (++s_txno >= ETH_DESC_CNT) s_txno = 0;
   }
-  ETH->DMASR = BIT(2) | BIT(5);  // Clear any prior TBUS/TUS
-  ETH->DMATPDR = 0;              // and resume
-  return len;
   (void) ifp;
+  return len;
 }
 
-static bool mip_driver_stm32_up(struct mip_if *ifp) {
-  uint32_t bsr = eth_read_phy(PHY_ADDR, PHY_BSR);
-  (void) ifp;
-  return bsr & BIT(2) ? 1 : 0;
+static bool mg_tcpip_driver_imxrt_up(struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_driver_imxrt_data *d =
+      (struct mg_tcpip_driver_imxrt_data *) ifp->driver_data;
+  uint8_t speed = MG_PHY_SPEED_10M;
+  bool up = false, full_duplex = false;
+  struct mg_phy phy = {enet_read_phy, enet_write_phy};
+  up = mg_phy_up(&phy, d->phy_addr, &full_duplex, &speed);
+  if ((ifp->state == MG_TCPIP_STATE_DOWN) && up) {  // link state just went up
+    // tmp = reg with flags set to the most likely situation: 100M full-duplex
+    // if(link is slow or half) set flags otherwise
+    // reg = tmp
+    uint32_t tcr = ENET->TCR | MG_BIT(2);             // Full-duplex
+    uint32_t rcr = ENET->RCR & ~MG_BIT(9);            // 100M
+    if (speed == MG_PHY_SPEED_10M) rcr |= MG_BIT(9);  // 10M
+    if (full_duplex == false) tcr &= ~MG_BIT(2);      // Half-duplex
+    ENET->TCR = tcr;  // IRQ handler does not fiddle with these registers
+    ENET->RCR = rcr;
+    MG_DEBUG(("Link is %uM %s-duplex", rcr & MG_BIT(9) ? 10 : 100,
+              tcr & MG_BIT(2) ? "full" : "half"));
+  }
+  return up;
 }
 
-void ETH_IRQHandler(void);
+void ENET_IRQHandler(void);
 static uint32_t s_rxno;
-void ETH_IRQHandler(void) {
-  qp_mark(QP_IRQTRIGGERED, 0);
-  if (ETH->DMASR & BIT(6)) {             // Frame received, loop
-    ETH->DMASR = BIT(16) | BIT(6);       // Clear flag
-    for (uint32_t i = 0; i < 10; i++) {  // read as they arrive but not forever
-      if (s_rxdesc[s_rxno][0] & BIT(31)) break;  // exit when done
-      if (((s_rxdesc[s_rxno][0] & (BIT(8) | BIT(9))) == (BIT(8) | BIT(9))) &&
-          !(s_rxdesc[s_rxno][0] & BIT(15))) {  // skip partial/errored frames
-        uint32_t len = ((s_rxdesc[s_rxno][0] >> 16) & (BIT(14) - 1));
-        //  printf("%lx %lu %lx %.8lx\n", s_rxno, len, s_rxdesc[s_rxno][0],
-        //  ETH->DMASR);
-        mip_qwrite(s_rxbuf[s_rxno], len > 4 ? len - 4 : len, s_ifp);
-      }
-      s_rxdesc[s_rxno][0] = BIT(31);
-      if (++s_rxno >= ETH_DESC_CNT) s_rxno = 0;
+void ENET_IRQHandler(void) {
+  ENET->EIR = MG_BIT(25);  // Ack IRQ
+  // Frame received, loop
+  for (uint32_t i = 0; i < 10; i++) {  // read as they arrive but not forever
+    uint32_t r = s_rxdesc[s_rxno].control;
+    if (r & MG_BIT(15)) break;  // exit when done
+    // skip partial/errored frames (Table 37-32)
+    if ((r & MG_BIT(11)) &&
+        !(r & (MG_BIT(5) | MG_BIT(4) | MG_BIT(2) | MG_BIT(1) | MG_BIT(0)))) {
+      size_t len = s_rxdesc[s_rxno].length;
+      mg_tcpip_qwrite(s_rxbuf[s_rxno], len > 4 ? len - 4 : len, s_ifp);
     }
+    s_rxdesc[s_rxno].control |= MG_BIT(15);
+    if (++s_rxno >= ETH_DESC_CNT) s_rxno = 0;
   }
-  ETH->DMASR = BIT(7);  // Clear possible RBUS while processing
-  ETH->DMARPDR = 0;     // and resume RX
+  ENET->RDAR = MG_BIT(24);  // Receive Descriptors have changed
+  // If b24 == 0, descriptors were exhausted and probably frames were dropped
 }
 
-struct mip_driver mip_driver_stm32 = {
-    mip_driver_stm32_init, mip_driver_stm32_tx, mip_driver_rx, mip_driver_stm32_up};
+struct mg_tcpip_driver mg_tcpip_driver_imxrt = {mg_tcpip_driver_imxrt_init,
+                                                mg_tcpip_driver_imxrt_tx, NULL,
+                                                mg_tcpip_driver_imxrt_up};
+
 #endif
 
 #ifdef MG_ENABLE_LINES
-#line 1 "mip/driver_tm4c.c"
+#line 1 "src/drivers/phy.c"
 #endif
 
 
-#if MG_ENABLE_MIP && defined(MG_ENABLE_DRIVER_TM4C) && MG_ENABLE_DRIVER_TM4C
-struct tm4c_emac {
-  volatile uint32_t EMACCFG, EMACFRAMEFLTR, EMACHASHTBLH, EMACHASHTBLL,
-      EMACMIIADDR, EMACMIIDATA, EMACFLOWCTL, EMACVLANTG, RESERVED0, EMACSTATUS,
-      EMACRWUFF, EMACPMTCTLSTAT, RESERVED1[2], EMACRIS, EMACIM, EMACADDR0H,
-      EMACADDR0L, EMACADDR1H, EMACADDR1L, EMACADDR2H, EMACADDR2L, EMACADDR3H,
-      EMACADDR3L, RESERVED2[31], EMACWDOGTO, RESERVED3[8], EMACMMCCTRL,
-      EMACMMCRXRIS, EMACMMCTXRIS, EMACMMCRXIM, EMACMMCTXIM, RESERVED4,
-      EMACTXCNTGB, RESERVED5[12], EMACTXCNTSCOL, EMACTXCNTMCOL, RESERVED6[4],
-      EMACTXOCTCNTG, RESERVED7[6], EMACRXCNTGB, RESERVED8[4], EMACRXCNTCRCERR,
-      EMACRXCNTALGNERR, RESERVED9[10], EMACRXCNTGUNI, RESERVED10[239],
-      EMACVLNINCREP, EMACVLANHASH, RESERVED11[93], EMACTIMSTCTRL, EMACSUBSECINC,
-      EMACTIMSEC, EMACTIMNANO, EMACTIMSECU, EMACTIMNANOU, EMACTIMADD,
-      EMACTARGSEC, EMACTARGNANO, EMACHWORDSEC, EMACTIMSTAT, EMACPPSCTRL,
-      RESERVED12[12], EMACPPS0INTVL, EMACPPS0WIDTH, RESERVED13[294],
-      EMACDMABUSMOD, EMACTXPOLLD, EMACRXPOLLD, EMACRXDLADDR, EMACTXDLADDR,
-      EMACDMARIS, EMACDMAOPMODE, EMACDMAIM, EMACMFBOC, EMACRXINTWDT,
-      RESERVED14[8], EMACHOSTXDESC, EMACHOSRXDESC, EMACHOSTXBA, EMACHOSRXBA,
-      RESERVED15[218], EMACPP, EMACPC, EMACCC, RESERVED16, EMACEPHYRIS,
-      EMACEPHYIM, EMACEPHYIMSC;
+enum {                      // ID1  ID2
+  MG_PHY_KSZ8x = 0x22,      // 0022 1561 - KSZ8081RNB
+  MG_PHY_DP83x = 0x2000,    // 2000 a140 - TI DP83825I
+  MG_PHY_DP83867 = 0xa231,  // 2000 a231 - TI DP83867I
+  MG_PHY_LAN87x = 0x7,      // 0007 c0fx - LAN8720
+  MG_PHY_RTL8201 = 0x1C     // 001c c816 - RTL8201
+};
+
+enum {
+  MG_PHY_REG_BCR = 0,
+  MG_PHY_REG_BSR = 1,
+  MG_PHY_REG_ID1 = 2,
+  MG_PHY_REG_ID2 = 3,
+  MG_PHY_DP83x_REG_PHYSTS = 16,
+  MG_PHY_DP83867_REG_PHYSTS = 17,
+  MG_PHY_DP83x_REG_RCSR = 23,
+  MG_PHY_DP83x_REG_LEDCR = 24,
+  MG_PHY_KSZ8x_REG_PC1R = 30,
+  MG_PHY_KSZ8x_REG_PC2R = 31,
+  MG_PHY_LAN87x_REG_SCSR = 31,
+  MG_PHY_RTL8201_REG_RMSR = 16,  // in page 7
+  MG_PHY_RTL8201_REG_PAGESEL = 31
+};
+
+static const char *mg_phy_id_to_str(uint16_t id1, uint16_t id2) {
+  switch (id1) {
+    case MG_PHY_DP83x:
+      switch (id2) {
+        case MG_PHY_DP83867:
+          return "DP83867";
+        default:
+          return "DP83x";
+      }
+    case MG_PHY_KSZ8x:
+      return "KSZ8x";
+    case MG_PHY_LAN87x:
+      return "LAN87x";
+    case MG_PHY_RTL8201:
+      return "RTL8201";
+    default:
+      return "unknown";
+  }
+  (void) id2;
+}
+
+void mg_phy_init(struct mg_phy *phy, uint8_t phy_addr, uint8_t config) {
+  uint16_t id1, id2;
+  phy->write_reg(phy_addr, MG_PHY_REG_BCR, MG_BIT(15));  // Reset PHY
+  while (phy->read_reg(phy_addr, MG_PHY_REG_BCR) & MG_BIT(15)) (void) 0;
+  // MG_PHY_REG_BCR[12]: Autonegotiation is default unless hw says otherwise
+
+  id1 = phy->read_reg(phy_addr, MG_PHY_REG_ID1);
+  id2 = phy->read_reg(phy_addr, MG_PHY_REG_ID2);
+  MG_INFO(("PHY ID: %#04x %#04x (%s)", id1, id2, mg_phy_id_to_str(id1, id2)));
+
+  if (id1 == MG_PHY_DP83x && id2 == MG_PHY_DP83867) {
+    phy->write_reg(phy_addr, 0x0d, 0x1f);    // write 0x10d to IO_MUX_CFG (0x0170)
+    phy->write_reg(phy_addr, 0x0e, 0x170);
+    phy->write_reg(phy_addr, 0x0d, 0x401f);
+    phy->write_reg(phy_addr, 0x0e, 0x10d);
+  }
+
+  if (config & MG_PHY_CLOCKS_MAC) {
+    // Use PHY crystal oscillator (preserve defaults)
+    // nothing to do
+  } else {  // MAC clocks PHY, PHY has no xtal
+    // Enable 50 MHz external ref clock at XI (preserve defaults)
+    if (id1 == MG_PHY_DP83x && id2 != MG_PHY_DP83867) {
+      phy->write_reg(phy_addr, MG_PHY_DP83x_REG_RCSR, MG_BIT(7) | MG_BIT(0));
+    } else if (id1 == MG_PHY_KSZ8x) {
+      phy->write_reg(phy_addr, MG_PHY_KSZ8x_REG_PC2R,
+                     MG_BIT(15) | MG_BIT(8) | MG_BIT(7));
+    } else if (id1 == MG_PHY_LAN87x) {
+      // nothing to do
+    } else if (id1 == MG_PHY_RTL8201) {
+      // assume PHY has been hardware strapped properly
+#if 0
+      phy->write_reg(phy_addr, MG_PHY_RTL8201_REG_PAGESEL, 7);  // Select page 7
+      phy->write_reg(phy_addr, MG_PHY_RTL8201_REG_RMSR, 0x1ffa);
+      phy->write_reg(phy_addr, MG_PHY_RTL8201_REG_PAGESEL, 0);  // Select page 0
+#endif
+    }
+  }
+
+  if (config & MG_PHY_LEDS_ACTIVE_HIGH && id1 == MG_PHY_DP83x) {
+    phy->write_reg(phy_addr, MG_PHY_DP83x_REG_LEDCR,
+                   MG_BIT(9) | MG_BIT(7));  // LED status, active high
+  }  // Other PHYs do not support this feature
+}
+
+bool mg_phy_up(struct mg_phy *phy, uint8_t phy_addr, bool *full_duplex,
+               uint8_t *speed) {
+  bool up = false;
+  uint16_t bsr = phy->read_reg(phy_addr, MG_PHY_REG_BSR);
+  if ((bsr & MG_BIT(5)) && !(bsr & MG_BIT(2)))  // some PHYs latch down events
+    bsr = phy->read_reg(phy_addr, MG_PHY_REG_BSR);  // read again
+  up = bsr & MG_BIT(2);
+  if (up && full_duplex != NULL && speed != NULL) {
+    uint16_t id1 = phy->read_reg(phy_addr, MG_PHY_REG_ID1);
+    if (id1 == MG_PHY_DP83x) {
+      uint16_t id2 = phy->read_reg(phy_addr, MG_PHY_REG_ID2);
+      if (id2 == MG_PHY_DP83867) {
+        uint16_t physts = phy->read_reg(phy_addr, MG_PHY_DP83867_REG_PHYSTS);
+        *full_duplex = physts & MG_BIT(13);
+        *speed = (physts & MG_BIT(15))   ? MG_PHY_SPEED_1000M
+                 : (physts & MG_BIT(14)) ? MG_PHY_SPEED_100M
+                                         : MG_PHY_SPEED_10M;
+      } else {
+        uint16_t physts = phy->read_reg(phy_addr, MG_PHY_DP83x_REG_PHYSTS);
+        *full_duplex = physts & MG_BIT(2);
+        *speed = (physts & MG_BIT(1)) ? MG_PHY_SPEED_10M : MG_PHY_SPEED_100M;
+      }
+    } else if (id1 == MG_PHY_KSZ8x) {
+      uint16_t pc1r = phy->read_reg(phy_addr, MG_PHY_KSZ8x_REG_PC1R);
+      *full_duplex = pc1r & MG_BIT(2);
+      *speed = (pc1r & 3) == 1 ? MG_PHY_SPEED_10M : MG_PHY_SPEED_100M;
+    } else if (id1 == MG_PHY_LAN87x) {
+      uint16_t scsr = phy->read_reg(phy_addr, MG_PHY_LAN87x_REG_SCSR);
+      *full_duplex = scsr & MG_BIT(4);
+      *speed = (scsr & MG_BIT(3)) ? MG_PHY_SPEED_100M : MG_PHY_SPEED_10M;
+    } else if (id1 == MG_PHY_RTL8201) {
+      uint16_t bcr = phy->read_reg(phy_addr, MG_PHY_REG_BCR);
+      *full_duplex = bcr & MG_BIT(8);
+      *speed = (bcr & MG_BIT(13)) ? MG_PHY_SPEED_100M : MG_PHY_SPEED_10M;
+    }
+  }
+  return up;
+}
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/drivers/ra.c"
+#endif
+
+
+#if MG_ENABLE_TCPIP && defined(MG_ENABLE_DRIVER_RA) && MG_ENABLE_DRIVER_RA
+struct ra_etherc {
+  volatile uint32_t ECMR, RESERVED, RFLR, RESERVED1, ECSR, RESERVED2, ECSIPR,
+      RESERVED3, PIR, RESERVED4, PSR, RESERVED5[5], RDMLR, RESERVED6[3], IPGR,
+      APR, MPR, RESERVED7, RFCF, TPAUSER, TPAUSECR, BCFRR, RESERVED8[20], MAHR,
+      RESERVED9, MALR, RESERVED10, TROCR, CDCR, LCCR, CNDCR, RESERVED11, CEFCR,
+      FRECR, TSFRCR, TLFRCR, RFCR, MAFCR;
 };
-#undef EMAC
-#define EMAC ((struct tm4c_emac *) (uintptr_t) 0x400EC000)
 
-#undef BIT
-#define BIT(x) ((uint32_t) 1 << (x))
-#define ETH_PKT_SIZE 1540  // Max frame size
+struct ra_edmac {
+  volatile uint32_t EDMR, RESERVED, EDTRR, RESERVED1, EDRRR, RESERVED2, TDLAR,
+      RESERVED3, RDLAR, RESERVED4, EESR, RESERVED5, EESIPR, RESERVED6, TRSCER,
+      RESERVED7, RMFCR, RESERVED8, TFTR, RESERVED9, FDR, RESERVED10, RMCR,
+      RESERVED11[2], TFUCR, RFOCR, IOSR, FCFTR, RESERVED12, RPADIR, TRIMD,
+      RESERVED13[18], RBWAR, RDFAR, RESERVED14, TBRAR, TDFAR;
+};
+
+#undef ETHERC
+#define ETHERC ((struct ra_etherc *) (uintptr_t) 0x40114100U)
+#undef EDMAC
+#define EDMAC ((struct ra_edmac *) (uintptr_t) 0x40114000U)
+#undef RASYSC
+#define RASYSC ((uint32_t *) (uintptr_t) 0x4001E000U)
+#undef ICU_IELSR
+#define ICU_IELSR ((uint32_t *) (uintptr_t) 0x40006300U)
+
+#define ETH_PKT_SIZE 1536  // Max frame size, multiple of 32
 #define ETH_DESC_CNT 4     // Descriptors count
-#define ETH_DS 4           // Descriptor size (words)
 
-static uint32_t s_rxdesc[ETH_DESC_CNT][ETH_DS];      // RX descriptors
-static uint32_t s_txdesc[ETH_DESC_CNT][ETH_DS];      // TX descriptors
-static uint8_t s_rxbuf[ETH_DESC_CNT][ETH_PKT_SIZE];  // RX ethernet buffers
-static uint8_t s_txbuf[ETH_DESC_CNT][ETH_PKT_SIZE];  // TX ethernet buffers
-static struct mip_if *s_ifp;                         // MIP interface
-enum { EPHY_ADDR = 0, EPHYBMCR = 0, EPHYBMSR = 1 };  // PHY constants
+// TODO(): handle these in a portable compiler-independent CMSIS-friendly way
+#define MG_16BYTE_ALIGNED __attribute__((aligned((16U))))
+#define MG_32BYTE_ALIGNED __attribute__((aligned((32U))))
 
-static inline void tm4cspin(volatile uint32_t count) {
+// Descriptors: 16-byte aligned
+// Buffers: 32-byte aligned (27.3.1)
+static volatile uint32_t s_rxdesc[ETH_DESC_CNT][4] MG_16BYTE_ALIGNED;
+static volatile uint32_t s_txdesc[ETH_DESC_CNT][4] MG_16BYTE_ALIGNED;
+static uint8_t s_rxbuf[ETH_DESC_CNT][ETH_PKT_SIZE] MG_32BYTE_ALIGNED;
+static uint8_t s_txbuf[ETH_DESC_CNT][ETH_PKT_SIZE] MG_32BYTE_ALIGNED;
+static struct mg_tcpip_if *s_ifp;  // MIP interface
+
+// fastest is 3 cycles (SUB + BNE) on a 3-stage pipeline or equivalent
+static inline void raspin(volatile uint32_t count) {
   while (count--) (void) 0;
 }
-
-static uint32_t emac_read_phy(uint8_t addr, uint8_t reg) {
-  EMAC->EMACMIIADDR &= (0xf << 2);
-  EMAC->EMACMIIADDR |= ((uint32_t) addr << 11) | ((uint32_t) reg << 6);
-  EMAC->EMACMIIADDR |= BIT(0);
-  while (EMAC->EMACMIIADDR & BIT(0)) tm4cspin(1);
-  return EMAC->EMACMIIDATA;
+// count to get the 200ns SMC semi-cycle period (2.5MHz) calling raspin():
+// SYS_FREQUENCY * 200ns / 3 = SYS_FREQUENCY / 15000000
+static uint32_t s_smispin;
+
+// Bit-banged SMI
+static void smi_preamble(void) {
+  unsigned int i = 32;
+  uint32_t pir = MG_BIT(1) | MG_BIT(2);  // write, mdio = 1, mdc = 0
+  ETHERC->PIR = pir;
+  while (i--) {
+    pir &= ~MG_BIT(0);  // mdc = 0
+    ETHERC->PIR = pir;
+    raspin(s_smispin);
+    pir |= MG_BIT(0);  // mdc = 1
+    ETHERC->PIR = pir;
+    raspin(s_smispin);
+  }
 }
-
-static void emac_write_phy(uint8_t addr, uint8_t reg, uint32_t val) {
-  EMAC->EMACMIIDATA = val;
-  EMAC->EMACMIIADDR &= (0xf << 2);
-  EMAC->EMACMIIADDR |= ((uint32_t) addr << 11) | ((uint32_t) reg << 6) | BIT(1);
-  EMAC->EMACMIIADDR |= BIT(0);
-  while (EMAC->EMACMIIADDR & BIT(0)) tm4cspin(1);
+static void smi_wr(uint16_t header, uint16_t data) {
+  uint32_t word = (header << 16) | data;
+  smi_preamble();
+  unsigned int i = 32;
+  while (i--) {
+    uint32_t pir = MG_BIT(1) |
+                   (word & 0x80000000 ? MG_BIT(2) : 0);  // write, mdc = 0, data
+    ETHERC->PIR = pir;
+    raspin(s_smispin);
+    pir |= MG_BIT(0);  // mdc = 1
+    ETHERC->PIR = pir;
+    raspin(s_smispin);
+    word <<= 1;
+  }
 }
-
-static uint32_t get_sysclk(void) {
-  struct sysctl {
-    volatile uint32_t DONTCARE0[44], RSCLKCFG, DONTCARE1[43], PLLFREQ0,
-        PLLFREQ1;
-  } *sysctl = (struct sysctl *) 0x400FE000;
-  uint32_t clk = 0, piosc = 16000000 /* 16 MHz */, mosc = 25000000 /* 25MHz */;
-  if (sysctl->RSCLKCFG & (1 << 28)) {  // USEPLL
-    uint32_t fin, vco, mdiv, n, q, psysdiv;
-    uint32_t pllsrc = (sysctl->RSCLKCFG & (0xf << 24)) >> 24;
-    if (pllsrc == 0) {
-      clk = piosc;
-    } else if (pllsrc == 3) {
-      clk = mosc;
-    } else {
-      MG_ERROR(("Unsupported clock source"));
-    }
-    q = (sysctl->PLLFREQ1 & (0x1f << 8)) >> 8;
-    n = (sysctl->PLLFREQ1 & (0x1f << 0)) >> 0;
-    fin = clk / ((q + 1) * (n + 1));
-    mdiv = (sysctl->PLLFREQ0 & (0x3ff << 0)) >>
-           0;  // mint + (mfrac / 1024); MFRAC not supported
-    psysdiv = (sysctl->RSCLKCFG & (0x3f << 0)) >> 0;
-    vco = (uint32_t) ((uint64_t) fin * mdiv);
-    return vco / (psysdiv + 1);
+static uint16_t smi_rd(uint16_t header) {
+  smi_preamble();
+  unsigned int i = 16;  // 2 LSb as turnaround
+  uint32_t pir;
+  while (i--) {
+    pir = (i > 1 ? MG_BIT(1) : 0) |
+          (header & 0x8000
+               ? MG_BIT(2)
+               : 0);  // mdc = 0, header, set read direction at turnaround
+    ETHERC->PIR = pir;
+    raspin(s_smispin);
+    pir |= MG_BIT(0);  // mdc = 1
+    ETHERC->PIR = pir;
+    raspin(s_smispin);
+    header <<= 1;
   }
-  uint32_t oscsrc = (sysctl->RSCLKCFG & (0xf << 20)) >> 20;
-  if (oscsrc == 0) {
-    clk = piosc;
-  } else if (oscsrc == 3) {
-    clk = mosc;
-  } else {
-    MG_ERROR(("Unsupported clock source"));
+  i = 16;
+  uint16_t data = 0;
+  while (i--) {
+    data <<= 1;
+    pir = 0;  // read, mdc = 0
+    ETHERC->PIR = pir;
+    raspin(s_smispin / 2);  // 1/4 clock period, 300ns max access time
+    data |= (uint16_t)(ETHERC->PIR & MG_BIT(3) ? 1 : 0);  // read mdio
+    raspin(s_smispin / 2);                    // 1/4 clock period
+    pir |= MG_BIT(0);                         // mdc = 1
+    ETHERC->PIR = pir;
+    raspin(s_smispin);
   }
-  uint32_t osysdiv = (sysctl->RSCLKCFG & (0xf << 16)) >> 16;
-  return clk / (osysdiv + 1);
+  return data;
 }
 
-//  Guess CR from SYSCLK. MDC clock is generated from SYSCLK (AHB); as per
-//  802.3, it must not exceed 2.5MHz (also 20.4.2.6) As the AHB clock can be
-//  derived from the PIOSC (internal RC), and it can go above  specs, the
-//  datasheets specify a range of frequencies and activate one of a series of
-//  dividers to keep the MDC clock safely below 2.5MHz. We guess a divider
-//  setting based on SYSCLK with a +5% drift. If the user uses a different clock
-//  from our defaults, needs to set the macros on top Valid for TM4C129x (20.7)
-//  (4.5% worst case drift)
-// The PHY receives the main oscillator (MOSC) (20.3.1)
-static int guess_mdc_cr(void) {
-  uint8_t crs[] = {2, 3, 0, 1};      // EMAC->MACMIIAR::CR values
-  uint8_t div[] = {16, 26, 42, 62};  // Respective HCLK dividers
-  uint32_t sysclk = get_sysclk();    // Guess system SYSCLK
-  int result = -1;                   // Invalid CR value
-  if (sysclk < 25000000) {
-    MG_ERROR(("SYSCLK too low"));
-  } else {
-    for (int i = 0; i < 4; i++) {
-      if (sysclk / div[i] <= 2375000UL /* 2.5MHz - 5% */) {
-        result = crs[i];
-        break;
-      }
-    }
-    if (result < 0) MG_ERROR(("SYSCLK too high"));
-  }
-  MG_DEBUG(("SYSCLK: %u, CR: %d", sysclk, result));
-  return result;
+static uint16_t raeth_read_phy(uint8_t addr, uint8_t reg) {
+  return smi_rd((uint16_t)((1 << 14) | (2 << 12) | (addr << 7) | (reg << 2) | (2 << 0)));
 }
 
-static bool mip_driver_tm4c_init(struct mip_if *ifp) {
-  struct mip_driver_tm4c_data *d = (struct mip_driver_tm4c_data *) ifp->driver_data;
+static void raeth_write_phy(uint8_t addr, uint8_t reg, uint16_t val) {
+  smi_wr((uint16_t)((1 << 14) | (1 << 12) | (addr << 7) | (reg << 2) | (2 << 0)), val);
+}
+
+// MDC clock is generated manually; as per 802.3, it must not exceed 2.5MHz
+static bool mg_tcpip_driver_ra_init(struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_driver_ra_data *d =
+      (struct mg_tcpip_driver_ra_data *) ifp->driver_data;
   s_ifp = ifp;
 
+  // Init SMI clock timing. If user told us the clock value, use it.
+  // TODO(): Otherwise, guess
+  s_smispin = d->clock / 15000000;
+
   // Init RX descriptors
   for (int i = 0; i < ETH_DESC_CNT; i++) {
-    s_rxdesc[i][0] = BIT(31);                            // Own
-    s_rxdesc[i][1] = sizeof(s_rxbuf[i]) | BIT(14);       // 2nd address chained
-    s_rxdesc[i][2] = (uint32_t) (uintptr_t) s_rxbuf[i];  // Point to data buffer
-    s_rxdesc[i][3] =
-        (uint32_t) (uintptr_t) s_rxdesc[(i + 1) % ETH_DESC_CNT];  // Chain
-    // MG_DEBUG(("%d %p", i, s_rxdesc[i]));
+    s_rxdesc[i][0] = MG_BIT(31);             // RACT
+    s_rxdesc[i][1] = ETH_PKT_SIZE << 16;     // RBL
+    s_rxdesc[i][2] = (uint32_t) s_rxbuf[i];  // Point to data buffer
   }
+  s_rxdesc[ETH_DESC_CNT - 1][0] |= MG_BIT(30);  // Wrap last descriptor
 
   // Init TX descriptors
   for (int i = 0; i < ETH_DESC_CNT; i++) {
-    s_txdesc[i][2] = (uint32_t) (uintptr_t) s_txbuf[i];  // Buf pointer
-    s_txdesc[i][3] =
-        (uint32_t) (uintptr_t) s_txdesc[(i + 1) % ETH_DESC_CNT];  // Chain
+    // TACT = 0
+    s_txdesc[i][2] = (uint32_t) s_txbuf[i];
   }
-
-  EMAC->EMACDMABUSMOD |= BIT(0);                            // Software reset
-  while ((EMAC->EMACDMABUSMOD & BIT(0)) != 0) tm4cspin(1);  // Wait until done
-
-  // Set MDC clock divider. If user told us the value, use it. Otherwise, guess
-  int cr = (d == NULL || d->mdc_cr < 0) ? guess_mdc_cr() : d->mdc_cr;
-  EMAC->EMACMIIADDR = ((uint32_t) cr & 0xf) << 2;
-
-  // NOTE(cpq): we do not use extended descriptor bit 7, and do not use
-  // hardware checksum. Therefore, descriptor size is 4, not 8
-  // EMAC->EMACDMABUSMOD = BIT(13) | BIT(16) | BIT(22) | BIT(23) | BIT(25);
-  EMAC->EMACIM = BIT(3) | BIT(9);  // Mask timestamp & PMT IT
-  EMAC->EMACFLOWCTL = BIT(7);      // Disable zero-quanta pause
-  // EMAC->EMACFRAMEFLTR = BIT(31);   // Receive all
-  // EMAC->EMACPC defaults to internal PHY (EPHY) in MMI mode
-  emac_write_phy(EPHY_ADDR, EPHYBMCR, BIT(15));  // Reset internal PHY (EPHY)
-  emac_write_phy(EPHY_ADDR, EPHYBMCR, BIT(12));  // Set autonegotiation
-  EMAC->EMACRXDLADDR = (uint32_t) (uintptr_t) s_rxdesc;  // RX descriptors
-  EMAC->EMACTXDLADDR = (uint32_t) (uintptr_t) s_txdesc;  // TX descriptors
-  EMAC->EMACDMAIM = BIT(6) | BIT(16);                    // RIE, NIE
-  EMAC->EMACCFG = BIT(2) | BIT(3) | BIT(11) | BIT(14);   // RE, TE, Duplex, Fast
-  EMAC->EMACDMAOPMODE =
-      BIT(1) | BIT(13) | BIT(21) | BIT(25);  // SR, ST, TSF, RSF
-  EMAC->EMACADDR0H = ((uint32_t) ifp->mac[5] << 8U) | ifp->mac[4];
-  EMAC->EMACADDR0L = (uint32_t) (ifp->mac[3] << 24) |
-                     ((uint32_t) ifp->mac[2] << 16) |
-                     ((uint32_t) ifp->mac[1] << 8) | ifp->mac[0];
-  // NOTE(scaprile) There are 3 additional slots for filtering, disabled by
-  // default. This also applies to the STM32 driver (at least for F7)
-
-  if (ifp->queue.len == 0) ifp->queue.len = 8192;
+  s_txdesc[ETH_DESC_CNT - 1][0] |= MG_BIT(30);  // Wrap last descriptor
+
+  EDMAC->EDMR = MG_BIT(0);  // Software reset, wait 64 PCLKA clocks (27.2.1)
+  uint32_t sckdivcr = RASYSC[8];  // get divisors from SCKDIVCR (8.2.2)
+  uint32_t ick = 1 << ((sckdivcr >> 24) & 7);   // sys_clock div
+  uint32_t pcka = 1 << ((sckdivcr >> 12) & 7);  // pclka div
+  raspin((64U * pcka) / (3U * ick));
+  EDMAC->EDMR = MG_BIT(6);  // Initialize, little-endian (27.2.1)
+
+  MG_DEBUG(("PHY addr: %d, smispin: %d", d->phy_addr, s_smispin));
+  struct mg_phy phy = {raeth_read_phy, raeth_write_phy};
+  mg_phy_init(&phy, d->phy_addr, 0); // MAC clocks PHY
+
+  // Select RMII mode,
+  ETHERC->ECMR = MG_BIT(2) | MG_BIT(1);  // 100M, Full-duplex, CRC
+  // ETHERC->ECMR |= MG_BIT(0);             // Receive all
+  ETHERC->RFLR = 1518;  // Set max rx length
+
+  EDMAC->RDLAR = (uint32_t) (uintptr_t) s_rxdesc;
+  EDMAC->TDLAR = (uint32_t) (uintptr_t) s_txdesc;
+  // MAC address filtering (bytes in reversed order)
+  ETHERC->MAHR = (uint32_t) (ifp->mac[0] << 24U) |
+                 ((uint32_t) ifp->mac[1] << 16U) |
+                 ((uint32_t) ifp->mac[2] << 8U) | ifp->mac[3];
+  ETHERC->MALR = ((uint32_t) ifp->mac[4] << 8U) | ifp->mac[5];
+
+  EDMAC->TFTR = 0;                        // Store and forward (27.2.10)
+  EDMAC->FDR = 0x070f;                    // (27.2.11)
+  EDMAC->RMCR = MG_BIT(0);                // (27.2.12)
+  ETHERC->ECMR |= MG_BIT(6) | MG_BIT(5);  // TE RE
+  EDMAC->EESIPR = MG_BIT(18);             // Enable Rx IRQ
+  EDMAC->EDRRR = MG_BIT(0);               // Receive Descriptors have changed
+  EDMAC->EDTRR = MG_BIT(0);               // Transmit Descriptors have changed
   return true;
 }
 
-static uint32_t s_txno;
-static size_t mip_driver_tm4c_tx(const void *buf, size_t len, struct mip_if *ifp) {
-  if (len > sizeof(s_txbuf[s_txno])) {
+// Transmit frame
+static size_t mg_tcpip_driver_ra_tx(const void *buf, size_t len,
+                                    struct mg_tcpip_if *ifp) {
+  static int s_txno;  // Current descriptor index
+  if (len > sizeof(s_txbuf[ETH_DESC_CNT])) {
     MG_ERROR(("Frame too big, %ld", (long) len));
-    len = 0;  // fail
-  } else if ((s_txdesc[s_txno][0] & BIT(31))) {
+    len = (size_t) -1;  // fail
+  } else if ((s_txdesc[s_txno][0] & MG_BIT(31))) {
+    ifp->nerr++;
     MG_ERROR(("No descriptors available"));
-    // printf("D0 %lx SR %lx\n", (long) s_txdesc[0][0], (long)
-    // EMAC->EMACDMARIS);
-    len = 0;  // fail
+    len = 0;  // retry later
   } else {
-    memcpy(s_txbuf[s_txno], buf, len);     // Copy data
-    s_txdesc[s_txno][1] = (uint32_t) len;  // Set data len
-    s_txdesc[s_txno][0] =
-        BIT(20) | BIT(28) | BIT(29) | BIT(30);  // Chain,FS,LS,IC
-    s_txdesc[s_txno][0] |= BIT(31);  // Set OWN bit - let DMA take over
+    memcpy(s_txbuf[s_txno], buf, len);            // Copy data
+    s_txdesc[s_txno][1] = len << 16;              // Set data len
+    s_txdesc[s_txno][0] |= MG_BIT(31) | 3 << 28;  // (27.3.1.1) mark valid
+    EDMAC->EDTRR = MG_BIT(0);                     // Transmit request
     if (++s_txno >= ETH_DESC_CNT) s_txno = 0;
   }
-  EMAC->EMACDMARIS = BIT(2) | BIT(5);  // Clear any prior TU/UNF
-  EMAC->EMACTXPOLLD = 0;               // and resume
   return len;
-  (void) ifp;
 }
 
-static bool mip_driver_tm4c_up(struct mip_if *ifp) {
-  uint32_t bmsr = emac_read_phy(EPHY_ADDR, EPHYBMSR);
-  (void) ifp;
-  return (bmsr & BIT(2)) ? 1 : 0;
+static bool mg_tcpip_driver_ra_up(struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_driver_ra_data *d =
+      (struct mg_tcpip_driver_ra_data *) ifp->driver_data;
+  uint8_t speed = MG_PHY_SPEED_10M;
+  bool up = false, full_duplex = false;
+  struct mg_phy phy = {raeth_read_phy, raeth_write_phy};
+  up = mg_phy_up(&phy, d->phy_addr, &full_duplex, &speed);
+  if ((ifp->state == MG_TCPIP_STATE_DOWN) && up) {  // link state just went up
+    // tmp = reg with flags set to the most likely situation: 100M full-duplex
+    // if(link is slow or half) set flags otherwise
+    // reg = tmp
+    uint32_t ecmr = ETHERC->ECMR | MG_BIT(2) | MG_BIT(1);  // 100M Full-duplex
+    if (speed == MG_PHY_SPEED_10M) ecmr &= ~MG_BIT(2);     // 10M
+    if (full_duplex == false) ecmr &= ~MG_BIT(1);          // Half-duplex
+    ETHERC->ECMR = ecmr;  // IRQ handler does not fiddle with these registers
+    MG_DEBUG(("Link is %uM %s-duplex", ecmr & MG_BIT(2) ? 100 : 10,
+              ecmr & MG_BIT(1) ? "full" : "half"));
+  }
+  return up;
 }
 
-void EMAC0_IRQHandler(void);
+void EDMAC_IRQHandler(void);
 static uint32_t s_rxno;
-void EMAC0_IRQHandler(void) {
-  qp_mark(QP_IRQTRIGGERED, 0);
-  if (EMAC->EMACDMARIS & BIT(6)) {        // Frame received, loop
-    EMAC->EMACDMARIS = BIT(16) | BIT(6);  // Clear flag
-    for (uint32_t i = 0; i < 10; i++) {   // read as they arrive but not forever
-      if (s_rxdesc[s_rxno][0] & BIT(31)) break;  // exit when done
-      if (((s_rxdesc[s_rxno][0] & (BIT(8) | BIT(9))) == (BIT(8) | BIT(9))) &&
-          !(s_rxdesc[s_rxno][0] & BIT(15))) {  // skip partial/errored frames
-        uint32_t len = ((s_rxdesc[s_rxno][0] >> 16) & (BIT(14) - 1));
-        //  printf("%lx %lu %lx %.8lx\n", s_rxno, len, s_rxdesc[s_rxno][0],
-        //  EMAC->EMACDMARIS);
-        mip_qwrite(s_rxbuf[s_rxno], len > 4 ? len - 4 : len, s_ifp);
-      }
-      s_rxdesc[s_rxno][0] = BIT(31);
-      if (++s_rxno >= ETH_DESC_CNT) s_rxno = 0;
+void EDMAC_IRQHandler(void) {
+  struct mg_tcpip_driver_ra_data *d =
+      (struct mg_tcpip_driver_ra_data *) s_ifp->driver_data;
+  EDMAC->EESR = MG_BIT(18);            // Ack IRQ in EDMAC 1st
+  ICU_IELSR[d->irqno] &= ~MG_BIT(16);  // Ack IRQ in ICU last
+  // Frame received, loop
+  for (uint32_t i = 0; i < 10; i++) {  // read as they arrive but not forever
+    uint32_t r = s_rxdesc[s_rxno][0];
+    if (r & MG_BIT(31)) break;  // exit when done
+    // skip partial/errored frames (27.3.1.2)
+    if ((r & (MG_BIT(29) | MG_BIT(28)) && !(r & MG_BIT(27)))) {
+      size_t len = s_rxdesc[s_rxno][1] & 0xffff;
+      mg_tcpip_qwrite(s_rxbuf[s_rxno], len, s_ifp);  // CRC already stripped
     }
+    s_rxdesc[s_rxno][0] |= MG_BIT(31);
+    if (++s_rxno >= ETH_DESC_CNT) s_rxno = 0;
   }
-  EMAC->EMACDMARIS = BIT(7);  // Clear possible RU while processing
-  EMAC->EMACRXPOLLD = 0;      // and resume RX
+  EDMAC->EDRRR = MG_BIT(0);  // Receive Descriptors have changed
+  // If b0 == 0, descriptors were exhausted and probably frames were dropped,
+  // (27.2.9 RMFCR counts them)
 }
 
-struct mip_driver mip_driver_tm4c = {mip_driver_tm4c_init, mip_driver_tm4c_tx,
-                                     mip_driver_rx, mip_driver_tm4c_up};
+struct mg_tcpip_driver mg_tcpip_driver_ra = {mg_tcpip_driver_ra_init,
+                                             mg_tcpip_driver_ra_tx, NULL,
+                                             mg_tcpip_driver_ra_up};
+
 #endif
 
 #ifdef MG_ENABLE_LINES
-#line 1 "mip/driver_w5500.c"
+#line 1 "src/drivers/same54.c"
 #endif
 
 
-#if MG_ENABLE_MIP
+#if MG_ENABLE_TCPIP && defined(MG_ENABLE_DRIVER_SAME54) && MG_ENABLE_DRIVER_SAME54
 
-enum { W5500_CR = 0, W5500_S0 = 1, W5500_TX0 = 2, W5500_RX0 = 3 };
+#include <sam.h>
 
-static void w5500_txn(struct mip_spi *s, uint8_t block, uint16_t addr, bool wr,
-                      void *buf, size_t len) {
-  uint8_t *p = (uint8_t *) buf;
-  uint8_t cmd[] = {(uint8_t) (addr >> 8), (uint8_t) (addr & 255),
-                   (uint8_t) ((block << 3) | (wr ? 4 : 0))};
-  s->begin(s->spi);
-  for (size_t i = 0; i < sizeof(cmd); i++) s->txn(s->spi, cmd[i]);
-  for (size_t i = 0; i < len; i++) {
-    uint8_t r = s->txn(s->spi, p[i]);
-    if (!wr) p[i] = r;
-  }
-  s->end(s->spi);
+#define ETH_PKT_SIZE 1536  // Max frame size
+#define ETH_DESC_CNT 4     // Descriptors count
+#define ETH_DS 2           // Descriptor size (words)
+
+static uint8_t s_rxbuf[ETH_DESC_CNT][ETH_PKT_SIZE];
+static uint8_t s_txbuf[ETH_DESC_CNT][ETH_PKT_SIZE];
+static uint32_t s_rxdesc[ETH_DESC_CNT][ETH_DS];  // RX descriptors
+static uint32_t s_txdesc[ETH_DESC_CNT][ETH_DS];  // TX descriptors
+static uint8_t s_txno;                           // Current TX descriptor
+static uint8_t s_rxno;                           // Current RX descriptor
+
+static struct mg_tcpip_if *s_ifp;  // MIP interface
+enum { MG_PHY_ADDR = 0, MG_PHYREG_BCR = 0, MG_PHYREG_BSR = 1 };
+
+#define MG_PHYREGBIT_BCR_DUPLEX_MODE MG_BIT(8)
+#define MG_PHYREGBIT_BCR_SPEED MG_BIT(13)
+#define MG_PHYREGBIT_BSR_LINK_STATUS MG_BIT(2)
+
+static uint16_t eth_read_phy(uint8_t addr, uint8_t reg) {
+  GMAC_REGS->GMAC_MAN = GMAC_MAN_CLTTO_Msk |
+                        GMAC_MAN_OP(2) |  // Setting the read operation
+                        GMAC_MAN_WTN(2) | GMAC_MAN_PHYA(addr) |  // PHY address
+                        GMAC_MAN_REGA(reg);  // Setting the register
+  while (!(GMAC_REGS->GMAC_NSR & GMAC_NSR_IDLE_Msk)) (void) 0;
+  return GMAC_REGS->GMAC_MAN & GMAC_MAN_DATA_Msk;  // Getting the read value
 }
 
-// clang-format off
-static  void w5500_wn(struct mip_spi *s, uint8_t block, uint16_t addr, void *buf, size_t len) { w5500_txn(s, block, addr, true, buf, len); }
-static  void w5500_w1(struct mip_spi *s, uint8_t block, uint16_t addr, uint8_t val) { w5500_wn(s, block, addr, &val, 1); }
-static  void w5500_w2(struct mip_spi *s, uint8_t block, uint16_t addr, uint16_t val) { uint8_t buf[2] = {(uint8_t) (val >> 8), (uint8_t) (val & 255)}; w5500_wn(s, block, addr, buf, sizeof(buf)); }
-static  void w5500_rn(struct mip_spi *s, uint8_t block, uint16_t addr, void *buf, size_t len) { w5500_txn(s, block, addr, false, buf, len); }
-static  uint8_t w5500_r1(struct mip_spi *s, uint8_t block, uint16_t addr) { uint8_t r = 0; w5500_rn(s, block, addr, &r, 1); return r; }
-static  uint16_t w5500_r2(struct mip_spi *s, uint8_t block, uint16_t addr) { uint8_t buf[2] = {0, 0}; w5500_rn(s, block, addr, buf, sizeof(buf)); return (uint16_t) ((buf[0] << 8) | buf[1]); }
-// clang-format on
+#if 0
+static void eth_write_phy(uint8_t addr, uint8_t reg, uint16_t val) {
+  GMAC_REGS->GMAC_MAN = GMAC_MAN_CLTTO_Msk | GMAC_MAN_OP(1) |   // Setting the write operation
+                        GMAC_MAN_WTN(2) | GMAC_MAN_PHYA(addr) | // PHY address
+                        GMAC_MAN_REGA(reg) | GMAC_MAN_DATA(val);  // Setting the register
+  while (!(GMAC_REGS->GMAC_NSR & GMAC_NSR_IDLE_Msk)); // Waiting until the write op is complete
+}
+#endif
 
-static size_t w5500_rx(void *buf, size_t buflen, struct mip_if *ifp) {
-  struct mip_spi *s = (struct mip_spi *) ifp->driver_data;
-  uint16_t r = 0, n = 0, len = (uint16_t) buflen, n2;     // Read recv len
-  while ((n2 = w5500_r2(s, W5500_S0, 0x26)) > n) n = n2;  // Until it is stable
-  // printf("RSR: %d\n", (int) n);
-  if (n > 0) {
-    uint16_t ptr = w5500_r2(s, W5500_S0, 0x28);  // Get read pointer
-    n = w5500_r2(s, W5500_RX0, ptr);             // Read frame length
-    if (n <= len + 2 && n > 1) {
-      r = (uint16_t) (n - 2);
-      w5500_rn(s, W5500_RX0, (uint16_t) (ptr + 2), buf, r);
+int get_clock_rate(struct mg_tcpip_driver_same54_data *d) {
+  if (d && d->mdc_cr >= 0 && d->mdc_cr <= 5) {
+    return d->mdc_cr;
+  } else {
+    // get MCLK from GCLK_GENERATOR 0
+    uint32_t div = 512;
+    uint32_t mclk;
+    if (!(GCLK_REGS->GCLK_GENCTRL[0] & GCLK_GENCTRL_DIVSEL_Msk)) {
+      div = ((GCLK_REGS->GCLK_GENCTRL[0] & 0x00FF0000) >> 16);
+      if (div == 0) div = 1;
     }
-    w5500_w2(s, W5500_S0, 0x28, (uint16_t) (ptr + n));  // Advance read pointer
-    w5500_w1(s, W5500_S0, 1, 0x40);                     // Sock0 CR -> RECV
-    // printf("  RX_RD: tot=%u n=%u r=%u\n", n2, n, r);
+    switch (GCLK_REGS->GCLK_GENCTRL[0] & GCLK_GENCTRL_SRC_Msk) {
+      case GCLK_GENCTRL_SRC_XOSC0_Val:
+        mclk = 32000000UL; /* 32MHz */
+        break;
+      case GCLK_GENCTRL_SRC_XOSC1_Val:
+        mclk = 32000000UL; /* 32MHz */
+        break;
+      case GCLK_GENCTRL_SRC_OSCULP32K_Val:
+        mclk = 32000UL;
+        break;
+      case GCLK_GENCTRL_SRC_XOSC32K_Val:
+        mclk = 32000UL;
+        break;
+      case GCLK_GENCTRL_SRC_DFLL_Val:
+        mclk = 48000000UL; /* 48MHz */
+        break;
+      case GCLK_GENCTRL_SRC_DPLL0_Val:
+        mclk = 200000000UL; /* 200MHz */
+        break;
+      case GCLK_GENCTRL_SRC_DPLL1_Val:
+        mclk = 200000000UL; /* 200MHz */
+        break;
+      default:
+        mclk = 200000000UL; /* 200MHz */
+    }
+
+    mclk /= div;
+    uint8_t crs[] = {0, 1, 2, 3, 4, 5};            // GMAC->NCFGR::CLK values
+    uint8_t dividers[] = {8, 16, 32, 48, 64, 96};  // Respective CLK dividers
+    for (int i = 0; i < 6; i++) {
+      if (mclk / dividers[i] <= 2375000UL /* 2.5MHz - 5% */) {
+        return crs[i];
+      }
+    }
+
+    return 5;
   }
-  return r;
 }
 
-static size_t w5500_tx(const void *buf, size_t buflen, struct mip_if *ifp) {
-  struct mip_spi *s = (struct mip_spi *) ifp->driver_data;
-  uint16_t n = 0, len = (uint16_t) buflen;
-  while (n < len) n = w5500_r2(s, W5500_S0, 0x20);      // Wait for space
-  uint16_t ptr = w5500_r2(s, W5500_S0, 0x24);           // Get write pointer
-  w5500_wn(s, W5500_TX0, ptr, (void *) buf, len);       // Write data
-  w5500_w2(s, W5500_S0, 0x24, (uint16_t) (ptr + len));  // Advance write pointer
-  w5500_w1(s, W5500_S0, 1, 0x20);                       // Sock0 CR -> SEND
-  for (int i = 0; i < 40; i++) {
-    uint8_t ir = w5500_r1(s, W5500_S0, 2);  // Read S0 IR
-    if (ir == 0) continue;
-    // printf("IR %d, len=%d, free=%d, ptr %d\n", ir, (int) len, (int) n, ptr);
-    w5500_w1(s, W5500_S0, 2, ir);  // Write S0 IR: clear it!
-    if (ir & 8) len = 0;           // Timeout. Report error
-    if (ir & (16 | 8)) break;      // Stop on SEND_OK or timeout
+static bool mg_tcpip_driver_same54_init(struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_driver_same54_data *d =
+      (struct mg_tcpip_driver_same54_data *) ifp->driver_data;
+  s_ifp = ifp;
+
+  MCLK_REGS->MCLK_APBCMASK |= MCLK_APBCMASK_GMAC_Msk;
+  MCLK_REGS->MCLK_AHBMASK |= MCLK_AHBMASK_GMAC_Msk;
+  GMAC_REGS->GMAC_NCFGR = GMAC_NCFGR_CLK(get_clock_rate(d));  // Set MDC divider
+  GMAC_REGS->GMAC_NCR = 0;                                    // Disable RX & TX
+  GMAC_REGS->GMAC_NCR |= GMAC_NCR_MPE_Msk;  // Enable MDC & MDIO
+
+  for (int i = 0; i < ETH_DESC_CNT; i++) {   // Init TX descriptors
+    s_txdesc[i][0] = (uint32_t) s_txbuf[i];  // Point to data buffer
+    s_txdesc[i][1] = MG_BIT(31);             // OWN bit
   }
-  return len;
+  s_txdesc[ETH_DESC_CNT - 1][1] |= MG_BIT(30);  // Last tx descriptor - wrap
+
+  GMAC_REGS->GMAC_DCFGR = GMAC_DCFGR_DRBS(0x18)  // DMA recv buf 1536
+                          | GMAC_DCFGR_RXBMS(GMAC_DCFGR_RXBMS_FULL_Val) |
+                          GMAC_DCFGR_TXPBMS(1);  // See #2487
+  for (int i = 0; i < ETH_DESC_CNT; i++) {       // Init RX descriptors
+    s_rxdesc[i][0] = (uint32_t) s_rxbuf[i];      // Address of the data buffer
+    s_rxdesc[i][1] = 0;                          // Clear status
+  }
+  s_rxdesc[ETH_DESC_CNT - 1][0] |= MG_BIT(1);  // Last rx descriptor - wrap
+
+  GMAC_REGS->GMAC_TBQB = (uint32_t) s_txdesc;  // about the descriptor addresses
+  GMAC_REGS->GMAC_RBQB = (uint32_t) s_rxdesc;  // Let the controller know
+
+  GMAC_REGS->SA[0].GMAC_SAB =
+      MG_U32(ifp->mac[3], ifp->mac[2], ifp->mac[1], ifp->mac[0]);
+  GMAC_REGS->SA[0].GMAC_SAT = MG_U32(0, 0, ifp->mac[5], ifp->mac[4]);
+
+  GMAC_REGS->GMAC_UR &= ~GMAC_UR_MII_Msk;  // Disable MII, use RMII
+  GMAC_REGS->GMAC_NCFGR |= GMAC_NCFGR_MAXFS_Msk | GMAC_NCFGR_MTIHEN_Msk |
+                           GMAC_NCFGR_EFRHD_Msk | GMAC_NCFGR_CAF_Msk;
+  GMAC_REGS->GMAC_TSR = GMAC_TSR_HRESP_Msk | GMAC_TSR_UND_Msk |
+                        GMAC_TSR_TXCOMP_Msk | GMAC_TSR_TFC_Msk |
+                        GMAC_TSR_TXGO_Msk | GMAC_TSR_RLE_Msk |
+                        GMAC_TSR_COL_Msk | GMAC_TSR_UBR_Msk;
+  GMAC_REGS->GMAC_RSR = GMAC_RSR_HNO_Msk | GMAC_RSR_RXOVR_Msk |
+                        GMAC_RSR_REC_Msk | GMAC_RSR_BNA_Msk;
+  GMAC_REGS->GMAC_IDR = ~0U;  // Disable interrupts, then enable required
+  GMAC_REGS->GMAC_IER = GMAC_IER_HRESP_Msk | GMAC_IER_ROVR_Msk |
+                        GMAC_IER_TCOMP_Msk | GMAC_IER_TFC_Msk |
+                        GMAC_IER_RLEX_Msk | GMAC_IER_TUR_Msk |
+                        GMAC_IER_RXUBR_Msk | GMAC_IER_RCOMP_Msk;
+  GMAC_REGS->GMAC_NCR |= GMAC_NCR_TXEN_Msk | GMAC_NCR_RXEN_Msk;
+  NVIC_EnableIRQ(GMAC_IRQn);
+
+  return true;
 }
 
-static bool w5500_init(struct mip_if *ifp) {
-  struct mip_spi *s = (struct mip_spi *) ifp->driver_data;
-  s->end(s->spi);
-  w5500_w1(s, W5500_CR, 0, 0x80);     // Reset chip: CR -> 0x80
-  w5500_w1(s, W5500_CR, 0x2e, 0);     // CR PHYCFGR -> reset
-  w5500_w1(s, W5500_CR, 0x2e, 0xf8);  // CR PHYCFGR -> set
-  // w5500_wn(s, W5500_CR, 9, s->mac, 6);      // Set source MAC
-  w5500_w1(s, W5500_S0, 0x1e, 16);          // Sock0 RX buf size
-  w5500_w1(s, W5500_S0, 0x1f, 16);          // Sock0 TX buf size
-  w5500_w1(s, W5500_S0, 0, 4);              // Sock0 MR -> MACRAW
-  w5500_w1(s, W5500_S0, 1, 1);              // Sock0 CR -> OPEN
-  return w5500_r1(s, W5500_S0, 3) == 0x42;  // Sock0 SR == MACRAW
+static size_t mg_tcpip_driver_same54_tx(const void *buf, size_t len,
+                                        struct mg_tcpip_if *ifp) {
+  if (len > sizeof(s_txbuf[s_txno])) {
+    MG_ERROR(("Frame too big, %ld", (long) len));
+    len = 0;  // Frame is too big
+  } else if ((s_txdesc[s_txno][1] & MG_BIT(31)) == 0) {
+    ifp->nerr++;
+    MG_ERROR(("No free descriptors"));
+    len = 0;  // All descriptors are busy, fail
+  } else {
+    uint32_t status = len | MG_BIT(15);  // Frame length, last chunk
+    if (s_txno == ETH_DESC_CNT - 1) status |= MG_BIT(30);  // wrap
+    memcpy(s_txbuf[s_txno], buf, len);                     // Copy data
+    s_txdesc[s_txno][1] = status;
+    if (++s_txno >= ETH_DESC_CNT) s_txno = 0;
+  }
+  __DSB();  // Ensure descriptors have been written
+  GMAC_REGS->GMAC_NCR |= GMAC_NCR_TSTART_Msk;  // Enable transmission
+  return len;
 }
 
-static bool w5500_up(struct mip_if *ifp) {
-  struct mip_spi *spi = (struct mip_spi *) ifp->driver_data;
-  uint8_t phycfgr = w5500_r1(spi, W5500_CR, 0x2e);
-  return phycfgr & 1;  // Bit 0 of PHYCFGR is LNK (0 - down, 1 - up)
+static bool mg_tcpip_driver_same54_up(struct mg_tcpip_if *ifp) {
+  uint16_t bsr = eth_read_phy(MG_PHY_ADDR, MG_PHYREG_BSR);
+  bool up = bsr & MG_PHYREGBIT_BSR_LINK_STATUS ? 1 : 0;
+
+  // If PHY is ready, update NCFGR accordingly
+  if (ifp->state == MG_TCPIP_STATE_DOWN && up) {
+    uint16_t bcr = eth_read_phy(MG_PHY_ADDR, MG_PHYREG_BCR);
+    bool fd = bcr & MG_PHYREGBIT_BCR_DUPLEX_MODE ? 1 : 0;
+    bool spd = bcr & MG_PHYREGBIT_BCR_SPEED ? 1 : 0;
+    GMAC_REGS->GMAC_NCFGR = (GMAC_REGS->GMAC_NCFGR &
+                             ~(GMAC_NCFGR_SPD_Msk | MG_PHYREGBIT_BCR_SPEED)) |
+                            GMAC_NCFGR_SPD(spd) | GMAC_NCFGR_FD(fd);
+  }
+
+  return up;
+}
+
+void GMAC_Handler(void);
+void GMAC_Handler(void) {
+  uint32_t isr = GMAC_REGS->GMAC_ISR;
+  uint32_t rsr = GMAC_REGS->GMAC_RSR;
+  uint32_t tsr = GMAC_REGS->GMAC_TSR;
+  if (isr & GMAC_ISR_RCOMP_Msk) {
+    if (rsr & GMAC_ISR_RCOMP_Msk) {
+      for (uint8_t i = 0; i < ETH_DESC_CNT; i++) {
+        if ((s_rxdesc[s_rxno][0] & MG_BIT(0)) == 0) break;
+        size_t len = s_rxdesc[s_rxno][1] & (MG_BIT(13) - 1);
+        mg_tcpip_qwrite(s_rxbuf[s_rxno], len, s_ifp);
+        s_rxdesc[s_rxno][0] &= ~MG_BIT(0);  // Disown
+        if (++s_rxno >= ETH_DESC_CNT) s_rxno = 0;
+      }
+    }
+  }
+
+  if ((tsr & (GMAC_TSR_HRESP_Msk | GMAC_TSR_UND_Msk | GMAC_TSR_TXCOMP_Msk |
+              GMAC_TSR_TFC_Msk | GMAC_TSR_TXGO_Msk | GMAC_TSR_RLE_Msk |
+              GMAC_TSR_COL_Msk | GMAC_TSR_UBR_Msk)) != 0) {
+    // MG_INFO((" --> %#x %#x", s_txdesc[s_txno][1], tsr));
+    if (!(s_txdesc[s_txno][1] & MG_BIT(31))) s_txdesc[s_txno][1] |= MG_BIT(31);
+  }
+
+  GMAC_REGS->GMAC_RSR = rsr;
+  GMAC_REGS->GMAC_TSR = tsr;
 }
 
-struct mip_driver mip_driver_w5500 = {w5500_init, w5500_tx, w5500_rx, w5500_up};
+struct mg_tcpip_driver mg_tcpip_driver_same54 = {
+    mg_tcpip_driver_same54_init, mg_tcpip_driver_same54_tx, NULL,
+    mg_tcpip_driver_same54_up};
 #endif
 
 #ifdef MG_ENABLE_LINES
-#line 1 "mip/mip.c"
+#line 1 "src/drivers/stm32f.c"
 #endif
 
 
-#if MG_ENABLE_MIP
-
-#define MIP_ETHEMERAL_PORT 49152
-#define U16(ptr) ((((uint16_t) (ptr)[0]) << 8) | (ptr)[1])
-#define PDIFF(a, b) ((size_t) (((char *) (b)) - ((char *) (a))))
-
-#ifndef MIP_QSIZE
-#define MIP_QSIZE (16 * 1024)  // Queue size
-#endif
+#if MG_ENABLE_TCPIP && defined(MG_ENABLE_DRIVER_STM32F) && \
+    MG_ENABLE_DRIVER_STM32F
+struct stm32f_eth {
+  volatile uint32_t MACCR, MACFFR, MACHTHR, MACHTLR, MACMIIAR, MACMIIDR, MACFCR,
+      MACVLANTR, RESERVED0[2], MACRWUFFR, MACPMTCSR, RESERVED1, MACDBGR, MACSR,
+      MACIMR, MACA0HR, MACA0LR, MACA1HR, MACA1LR, MACA2HR, MACA2LR, MACA3HR,
+      MACA3LR, RESERVED2[40], MMCCR, MMCRIR, MMCTIR, MMCRIMR, MMCTIMR,
+      RESERVED3[14], MMCTGFSCCR, MMCTGFMSCCR, RESERVED4[5], MMCTGFCR,
+      RESERVED5[10], MMCRFCECR, MMCRFAECR, RESERVED6[10], MMCRGUFCR,
+      RESERVED7[334], PTPTSCR, PTPSSIR, PTPTSHR, PTPTSLR, PTPTSHUR, PTPTSLUR,
+      PTPTSAR, PTPTTHR, PTPTTLR, RESERVED8, PTPTSSR, PTPPPSCR, RESERVED9[564],
+      DMABMR, DMATPDR, DMARPDR, DMARDLAR, DMATDLAR, DMASR, DMAOMR, DMAIER,
+      DMAMFBOCR, DMARSWTR, RESERVED10[8], DMACHTDR, DMACHRDR, DMACHTBAR,
+      DMACHRBAR;
+};
+#undef ETH
+#define ETH ((struct stm32f_eth *) (uintptr_t) 0x40028000)
 
-#ifndef MIP_TCP_KEEPALIVE_MS
-#define MIP_TCP_KEEPALIVE_MS 45000  // TCP keep-alive period, ms
-#endif
+#define ETH_PKT_SIZE 1540  // Max frame size
+#define ETH_DESC_CNT 4     // Descriptors count
+#define ETH_DS 4           // Descriptor size (words)
 
-#define MIP_TCP_ACK_MS 150  // Timeout for ACKing
+static uint32_t s_rxdesc[ETH_DESC_CNT][ETH_DS];      // RX descriptors
+static uint32_t s_txdesc[ETH_DESC_CNT][ETH_DS];      // TX descriptors
+static uint8_t s_rxbuf[ETH_DESC_CNT][ETH_PKT_SIZE];  // RX ethernet buffers
+static uint8_t s_txbuf[ETH_DESC_CNT][ETH_PKT_SIZE];  // TX ethernet buffers
+static uint8_t s_txno;                               // Current TX descriptor
+static uint8_t s_rxno;                               // Current RX descriptor
 
-struct connstate {
-  uint32_t seq, ack;           // TCP seq/ack counters
-  uint64_t timer;              // TCP keep-alive / ACK timer
-  uint8_t mac[6];              // Peer MAC address
-  uint8_t ttype;               // Timer type. 0: ack, 1: keep-alive
-#define MIP_TTYPE_KEEPALIVE 0  // Connection is idle for long, send keepalive
-#define MIP_TTYPE_ACK 1        // Peer sent us data, we have to ack it soon
-  uint8_t tmiss;               // Number of keep-alive misses
-  struct mg_iobuf raw;         // For TLS only. Incoming raw data
-};
+static struct mg_tcpip_if *s_ifp;  // MIP interface
 
-#pragma pack(push, 1)
+static uint16_t eth_read_phy(uint8_t addr, uint8_t reg) {
+  ETH->MACMIIAR &= (7 << 2);
+  ETH->MACMIIAR |= ((uint32_t) addr << 11) | ((uint32_t) reg << 6);
+  ETH->MACMIIAR |= MG_BIT(0);
+  while (ETH->MACMIIAR & MG_BIT(0)) (void) 0;
+  return ETH->MACMIIDR & 0xffff;
+}
 
-struct lcp {
-  uint8_t addr, ctrl, proto[2], code, id, len[2];
-};
+static void eth_write_phy(uint8_t addr, uint8_t reg, uint16_t val) {
+  ETH->MACMIIDR = val;
+  ETH->MACMIIAR &= (7 << 2);
+  ETH->MACMIIAR |= ((uint32_t) addr << 11) | ((uint32_t) reg << 6) | MG_BIT(1);
+  ETH->MACMIIAR |= MG_BIT(0);
+  while (ETH->MACMIIAR & MG_BIT(0)) (void) 0;
+}
 
-struct eth {
-  uint8_t dst[6];  // Destination MAC address
-  uint8_t src[6];  // Source MAC address
-  uint16_t type;   // Ethernet type
-};
+static uint32_t get_hclk(void) {
+  struct rcc {
+    volatile uint32_t CR, PLLCFGR, CFGR;
+  } *rcc = (struct rcc *) 0x40023800;
+  uint32_t clk = 0, hsi = 16000000 /* 16 MHz */, hse = 8000000 /* 8MHz */;
 
-struct ip {
-  uint8_t ver;    // Version
-  uint8_t tos;    // Unused
-  uint16_t len;   // Length
-  uint16_t id;    // Unused
-  uint16_t frag;  // Fragmentation
-  uint8_t ttl;    // Time to live
-  uint8_t proto;  // Upper level protocol
-  uint16_t csum;  // Checksum
-  uint32_t src;   // Source IP
-  uint32_t dst;   // Destination IP
-};
+  if (rcc->CFGR & (1 << 2)) {
+    clk = hse;
+  } else if (rcc->CFGR & (1 << 3)) {
+    uint32_t vco, m, n, p;
+    m = (rcc->PLLCFGR & (0x3f << 0)) >> 0;
+    n = (rcc->PLLCFGR & (0x1ff << 6)) >> 6;
+    p = (((rcc->PLLCFGR & (3 << 16)) >> 16) + 1) * 2;
+    clk = (rcc->PLLCFGR & (1 << 22)) ? hse : hsi;
+    vco = (uint32_t) ((uint64_t) clk * n / m);
+    clk = vco / p;
+  } else {
+    clk = hsi;
+  }
+  uint32_t hpre = (rcc->CFGR & (15 << 4)) >> 4;
+  if (hpre < 8) return clk;
 
-struct ip6 {
-  uint8_t ver;      // Version
-  uint8_t opts[3];  // Options
-  uint16_t len;     // Length
-  uint8_t proto;    // Upper level protocol
-  uint8_t ttl;      // Time to live
-  uint8_t src[16];  // Source IP
-  uint8_t dst[16];  // Destination IP
-};
+  uint8_t ahbptab[8] = {1, 2, 3, 4, 6, 7, 8, 9};  // log2(div)
+  return ((uint32_t) clk) >> ahbptab[hpre - 8];
+}
 
-struct icmp {
-  uint8_t type;
-  uint8_t code;
-  uint16_t csum;
-};
+//  Guess CR from HCLK. MDC clock is generated from HCLK (AHB); as per 802.3,
+//  it must not exceed 2.5MHz As the AHB clock can be (and usually is) derived
+//  from the HSI (internal RC), and it can go above specs, the datasheets
+//  specify a range of frequencies and activate one of a series of dividers to
+//  keep the MDC clock safely below 2.5MHz. We guess a divider setting based on
+//  HCLK with a +5% drift. If the user uses a different clock from our
+//  defaults, needs to set the macros on top Valid for STM32F74xxx/75xxx
+//  (38.8.1) and STM32F42xxx/43xxx (33.8.1) (both 4.5% worst case drift)
+static int guess_mdc_cr(void) {
+  uint8_t crs[] = {2, 3, 0, 1, 4, 5};          // ETH->MACMIIAR::CR values
+  uint8_t div[] = {16, 26, 42, 62, 102, 124};  // Respective HCLK dividers
+  uint32_t hclk = get_hclk();                  // Guess system HCLK
+  int result = -1;                             // Invalid CR value
+  if (hclk < 25000000) {
+    MG_ERROR(("HCLK too low"));
+  } else {
+    for (int i = 0; i < 6; i++) {
+      if (hclk / div[i] <= 2375000UL /* 2.5MHz - 5% */) {
+        result = crs[i];
+        break;
+      }
+    }
+    if (result < 0) MG_ERROR(("HCLK too high"));
+  }
+  MG_DEBUG(("HCLK: %u, CR: %d", hclk, result));
+  return result;
+}
 
-struct arp {
-  uint16_t fmt;    // Format of hardware address
-  uint16_t pro;    // Format of protocol address
-  uint8_t hlen;    // Length of hardware address
-  uint8_t plen;    // Length of protocol address
-  uint16_t op;     // Operation
-  uint8_t sha[6];  // Sender hardware address
-  uint32_t spa;    // Sender protocol address
-  uint8_t tha[6];  // Target hardware address
-  uint32_t tpa;    // Target protocol address
-};
+static bool mg_tcpip_driver_stm32f_init(struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_driver_stm32f_data *d =
+      (struct mg_tcpip_driver_stm32f_data *) ifp->driver_data;
+  uint8_t phy_addr = d == NULL ? 0 : d->phy_addr;
+  s_ifp = ifp;
 
-struct tcp {
-  uint16_t sport;  // Source port
-  uint16_t dport;  // Destination port
-  uint32_t seq;    // Sequence number
-  uint32_t ack;    // Acknowledgement number
-  uint8_t off;     // Data offset
-  uint8_t flags;   // TCP flags
-#define TH_FIN 0x01
-#define TH_SYN 0x02
-#define TH_RST 0x04
-#define TH_PUSH 0x08
-#define TH_ACK 0x10
-#define TH_URG 0x20
-#define TH_ECE 0x40
-#define TH_CWR 0x80
-  uint16_t win;   // Window
-  uint16_t csum;  // Checksum
-  uint16_t urp;   // Urgent pointer
-};
+  // Init RX descriptors
+  for (int i = 0; i < ETH_DESC_CNT; i++) {
+    s_rxdesc[i][0] = MG_BIT(31);                         // Own
+    s_rxdesc[i][1] = sizeof(s_rxbuf[i]) | MG_BIT(14);    // 2nd address chained
+    s_rxdesc[i][2] = (uint32_t) (uintptr_t) s_rxbuf[i];  // Point to data buffer
+    s_rxdesc[i][3] =
+        (uint32_t) (uintptr_t) s_rxdesc[(i + 1) % ETH_DESC_CNT];  // Chain
+  }
 
-struct udp {
-  uint16_t sport;  // Source port
-  uint16_t dport;  // Destination port
-  uint16_t len;    // UDP length
-  uint16_t csum;   // UDP checksum
-};
+  // Init TX descriptors
+  for (int i = 0; i < ETH_DESC_CNT; i++) {
+    s_txdesc[i][2] = (uint32_t) (uintptr_t) s_txbuf[i];  // Buf pointer
+    s_txdesc[i][3] =
+        (uint32_t) (uintptr_t) s_txdesc[(i + 1) % ETH_DESC_CNT];  // Chain
+  }
 
-struct dhcp {
-  uint8_t op, htype, hlen, hops;
-  uint32_t xid;
-  uint16_t secs, flags;
-  uint32_t ciaddr, yiaddr, siaddr, giaddr;
-  uint8_t hwaddr[208];
-  uint32_t magic;
-  uint8_t options[32];
-};
+  ETH->DMABMR |= MG_BIT(0);                         // Software reset
+  while ((ETH->DMABMR & MG_BIT(0)) != 0) (void) 0;  // Wait until done
 
-#pragma pack(pop)
+  // Set MDC clock divider. If user told us the value, use it. Otherwise, guess
+  int cr = (d == NULL || d->mdc_cr < 0) ? guess_mdc_cr() : d->mdc_cr;
+  ETH->MACMIIAR = ((uint32_t) cr & 7) << 2;
 
-struct pkt {
-  struct mg_str raw;  // Raw packet data
-  struct mg_str pay;  // Payload data
-  struct eth *eth;
-  struct llc *llc;
-  struct arp *arp;
-  struct ip *ip;
-  struct ip6 *ip6;
-  struct icmp *icmp;
-  struct tcp *tcp;
-  struct udp *udp;
-  struct dhcp *dhcp;
-};
+  // NOTE(cpq): we do not use extended descriptor bit 7, and do not use
+  // hardware checksum. Therefore, descriptor size is 4, not 8
+  // ETH->DMABMR = MG_BIT(13) | MG_BIT(16) | MG_BIT(22) | MG_BIT(23) |
+  // MG_BIT(25);
+  ETH->MACIMR = MG_BIT(3) | MG_BIT(9);  // Mask timestamp & PMT IT
+  ETH->MACFCR = MG_BIT(7);              // Disable zero quarta pause
+  // ETH->MACFFR = MG_BIT(31);                            // Receive all
+  struct mg_phy phy = {eth_read_phy, eth_write_phy};
+  mg_phy_init(&phy, phy_addr, MG_PHY_CLOCKS_MAC);
+  ETH->DMARDLAR = (uint32_t) (uintptr_t) s_rxdesc;  // RX descriptors
+  ETH->DMATDLAR = (uint32_t) (uintptr_t) s_txdesc;  // RX descriptors
+  ETH->DMAIER = MG_BIT(6) | MG_BIT(16);             // RIE, NISE
+  ETH->MACCR =
+      MG_BIT(2) | MG_BIT(3) | MG_BIT(11) | MG_BIT(14);  // RE, TE, Duplex, Fast
+  ETH->DMAOMR =
+      MG_BIT(1) | MG_BIT(13) | MG_BIT(21) | MG_BIT(25);  // SR, ST, TSF, RSF
 
-static void q_copyin(struct queue *q, const uint8_t *buf, size_t len,
-                     size_t head) {
-  size_t left = q->len - head;
-  memcpy(&q->buf[head], buf, left < len ? left : len);
-  if (left < len) memcpy(q->buf, &buf[left], len - left);
+  // MAC address filtering
+  ETH->MACA0HR = ((uint32_t) ifp->mac[5] << 8U) | ifp->mac[4];
+  ETH->MACA0LR = (uint32_t) (ifp->mac[3] << 24) |
+                 ((uint32_t) ifp->mac[2] << 16) |
+                 ((uint32_t) ifp->mac[1] << 8) | ifp->mac[0];
+  return true;
 }
 
-static void q_copyout(struct queue *q, uint8_t *buf, size_t len, size_t tail) {
-  size_t left = q->len - tail;
-  memcpy(buf, &q->buf[tail], left < len ? left : len);
-  if (left < len) memcpy(&buf[left], q->buf, len - left);
+static size_t mg_tcpip_driver_stm32f_tx(const void *buf, size_t len,
+                                        struct mg_tcpip_if *ifp) {
+  if (len > sizeof(s_txbuf[s_txno])) {
+    MG_ERROR(("Frame too big, %ld", (long) len));
+    len = 0;  // Frame is too big
+  } else if ((s_txdesc[s_txno][0] & MG_BIT(31))) {
+    ifp->nerr++;
+    MG_ERROR(("No free descriptors"));
+    // printf("D0 %lx SR %lx\n", (long) s_txdesc[0][0], (long) ETH->DMASR);
+    len = 0;  // All descriptors are busy, fail
+  } else {
+    memcpy(s_txbuf[s_txno], buf, len);                           // Copy data
+    s_txdesc[s_txno][1] = (uint32_t) len;                        // Set data len
+    s_txdesc[s_txno][0] = MG_BIT(20) | MG_BIT(28) | MG_BIT(29);  // Chain,FS,LS
+    s_txdesc[s_txno][0] |= MG_BIT(31);  // Set OWN bit - let DMA take over
+    if (++s_txno >= ETH_DESC_CNT) s_txno = 0;
+  }
+  MG_DSB();                            // ensure descriptors have been written
+  ETH->DMASR = MG_BIT(2) | MG_BIT(5);  // Clear any prior TBUS/TUS
+  ETH->DMATPDR = 0;                    // and resume
+  return len;
 }
 
-static bool q_write(struct queue *q, const void *buf, size_t len) {
-  bool success = false;
-  size_t left = (q->len - q->head + q->tail - 1) % q->len;
-  if (len + sizeof(size_t) <= left) {
-    q_copyin(q, (uint8_t *) &len, sizeof(len), q->head);
-    q_copyin(q, (uint8_t *) buf, len, (q->head + sizeof(size_t)) % q->len);
-    q->head = (q->head + sizeof(len) + len) % q->len;
-    success = true;
+static bool mg_tcpip_driver_stm32f_up(struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_driver_stm32f_data *d =
+      (struct mg_tcpip_driver_stm32f_data *) ifp->driver_data;
+  uint8_t phy_addr = d == NULL ? 0 : d->phy_addr;
+  uint8_t speed = MG_PHY_SPEED_10M;
+  bool up = false, full_duplex = false;
+  struct mg_phy phy = {eth_read_phy, eth_write_phy};
+  up = mg_phy_up(&phy, phy_addr, &full_duplex, &speed);
+  if ((ifp->state == MG_TCPIP_STATE_DOWN) && up) {  // link state just went up
+    // tmp = reg with flags set to the most likely situation: 100M full-duplex
+    // if(link is slow or half) set flags otherwise
+    // reg = tmp
+    uint32_t maccr = ETH->MACCR | MG_BIT(14) | MG_BIT(11);  // 100M, Full-duplex
+    if (speed == MG_PHY_SPEED_10M) maccr &= ~MG_BIT(14);    // 10M
+    if (full_duplex == false) maccr &= ~MG_BIT(11);         // Half-duplex
+    ETH->MACCR = maccr;  // IRQ handler does not fiddle with this register
+    MG_DEBUG(("Link is %uM %s-duplex", maccr & MG_BIT(14) ? 100 : 10,
+              maccr & MG_BIT(11) ? "full" : "half"));
   }
-  return success;
+  return up;
 }
 
-#ifdef MIP_QPROFILE
-static inline size_t q_space(struct queue *q) {
-  return q->tail > q->head ? q->tail - q->head : q->tail + (q->len - q->head);
+#ifdef __riscv
+__attribute__((interrupt()))  // For RISCV CH32V307, which share the same MAC
+#endif
+void ETH_IRQHandler(void);
+void ETH_IRQHandler(void) {
+  if (ETH->DMASR & MG_BIT(6)) {           // Frame received, loop
+    ETH->DMASR = MG_BIT(16) | MG_BIT(6);  // Clear flag
+    for (uint32_t i = 0; i < 10; i++) {   // read as they arrive but not forever
+      if (s_rxdesc[s_rxno][0] & MG_BIT(31)) break;  // exit when done
+      if (((s_rxdesc[s_rxno][0] & (MG_BIT(8) | MG_BIT(9))) ==
+           (MG_BIT(8) | MG_BIT(9))) &&
+          !(s_rxdesc[s_rxno][0] & MG_BIT(15))) {  // skip partial/errored frames
+        uint32_t len = ((s_rxdesc[s_rxno][0] >> 16) & (MG_BIT(14) - 1));
+        //  printf("%lx %lu %lx %.8lx\n", s_rxno, len, s_rxdesc[s_rxno][0],
+        //  ETH->DMASR);
+        mg_tcpip_qwrite(s_rxbuf[s_rxno], len > 4 ? len - 4 : len, s_ifp);
+      }
+      s_rxdesc[s_rxno][0] = MG_BIT(31);
+      if (++s_rxno >= ETH_DESC_CNT) s_rxno = 0;
+    }
+  }
+  // Cleanup flags
+  ETH->DMASR = MG_BIT(16)    // NIS, normal interrupt summary
+               | MG_BIT(7);  // Clear possible RBUS while processing
+  ETH->DMARPDR = 0;          // and resume RX
 }
+
+struct mg_tcpip_driver mg_tcpip_driver_stm32f = {
+    mg_tcpip_driver_stm32f_init, mg_tcpip_driver_stm32f_tx, NULL,
+    mg_tcpip_driver_stm32f_up};
 #endif
 
-static inline size_t q_avail(struct queue *q) {
-  size_t n = 0;
-  if (q->tail != q->head) q_copyout(q, (uint8_t *) &n, sizeof(n), q->tail);
-  return n;
-}
+#ifdef MG_ENABLE_LINES
+#line 1 "src/drivers/stm32h.c"
+#endif
 
-static size_t q_read(struct queue *q, void *buf) {
-  size_t n = q_avail(q);
-  if (n > 0) {
-    q_copyout(q, (uint8_t *) buf, n, (q->tail + sizeof(n)) % q->len);
-    q->tail = (q->tail + sizeof(n) + n) % q->len;
-  }
-  return n;
-}
 
-static struct mg_str mkstr(void *buf, size_t len) {
-  struct mg_str str = {(char *) buf, len};
-  return str;
-}
+#if MG_ENABLE_TCPIP && defined(MG_ENABLE_DRIVER_STM32H) && \
+    MG_ENABLE_DRIVER_STM32H
+struct stm32h_eth {
+  volatile uint32_t MACCR, MACECR, MACPFR, MACWTR, MACHT0R, MACHT1R,
+      RESERVED1[14], MACVTR, RESERVED2, MACVHTR, RESERVED3, MACVIR, MACIVIR,
+      RESERVED4[2], MACTFCR, RESERVED5[7], MACRFCR, RESERVED6[7], MACISR,
+      MACIER, MACRXTXSR, RESERVED7, MACPCSR, MACRWKPFR, RESERVED8[2], MACLCSR,
+      MACLTCR, MACLETR, MAC1USTCR, RESERVED9[12], MACVR, MACDR, RESERVED10,
+      MACHWF0R, MACHWF1R, MACHWF2R, RESERVED11[54], MACMDIOAR, MACMDIODR,
+      RESERVED12[2], MACARPAR, RESERVED13[59], MACA0HR, MACA0LR, MACA1HR,
+      MACA1LR, MACA2HR, MACA2LR, MACA3HR, MACA3LR, RESERVED14[248], MMCCR,
+      MMCRIR, MMCTIR, MMCRIMR, MMCTIMR, RESERVED15[14], MMCTSCGPR, MMCTMCGPR,
+      RESERVED16[5], MMCTPCGR, RESERVED17[10], MMCRCRCEPR, MMCRAEPR,
+      RESERVED18[10], MMCRUPGR, RESERVED19[9], MMCTLPIMSTR, MMCTLPITCR,
+      MMCRLPIMSTR, MMCRLPITCR, RESERVED20[65], MACL3L4C0R, MACL4A0R,
+      RESERVED21[2], MACL3A0R0R, MACL3A1R0R, MACL3A2R0R, MACL3A3R0R,
+      RESERVED22[4], MACL3L4C1R, MACL4A1R, RESERVED23[2], MACL3A0R1R,
+      MACL3A1R1R, MACL3A2R1R, MACL3A3R1R, RESERVED24[108], MACTSCR, MACSSIR,
+      MACSTSR, MACSTNR, MACSTSUR, MACSTNUR, MACTSAR, RESERVED25, MACTSSR,
+      RESERVED26[3], MACTTSSNR, MACTTSSSR, RESERVED27[2], MACACR, RESERVED28,
+      MACATSNR, MACATSSR, MACTSIACR, MACTSEACR, MACTSICNR, MACTSECNR,
+      RESERVED29[4], MACPPSCR, RESERVED30[3], MACPPSTTSR, MACPPSTTNR, MACPPSIR,
+      MACPPSWR, RESERVED31[12], MACPOCR, MACSPI0R, MACSPI1R, MACSPI2R, MACLMIR,
+      RESERVED32[11], MTLOMR, RESERVED33[7], MTLISR, RESERVED34[55], MTLTQOMR,
+      MTLTQUR, MTLTQDR, RESERVED35[8], MTLQICSR, MTLRQOMR, MTLRQMPOCR, MTLRQDR,
+      RESERVED36[177], DMAMR, DMASBMR, DMAISR, DMADSR, RESERVED37[60], DMACCR,
+      DMACTCR, DMACRCR, RESERVED38[2], DMACTDLAR, RESERVED39, DMACRDLAR,
+      DMACTDTPR, RESERVED40, DMACRDTPR, DMACTDRLR, DMACRDRLR, DMACIER,
+      DMACRIWTR, DMACSFCSR, RESERVED41, DMACCATDR, RESERVED42, DMACCARDR,
+      RESERVED43, DMACCATBR, RESERVED44, DMACCARBR, DMACSR, RESERVED45[2],
+      DMACMFCR;
+};
+#undef ETH
+#define ETH \
+  ((struct stm32h_eth *) (uintptr_t) (0x40000000UL + 0x00020000UL + 0x8000UL))
 
-static void mkpay(struct pkt *pkt, void *p) {
-  pkt->pay = mkstr(p, (size_t) (&pkt->raw.ptr[pkt->raw.len] - (char *) p));
+#define ETH_PKT_SIZE 1540  // Max frame size
+#define ETH_DESC_CNT 4     // Descriptors count
+#define ETH_DS 4           // Descriptor size (words)
+
+static volatile uint32_t s_rxdesc[ETH_DESC_CNT][ETH_DS];  // RX descriptors
+static volatile uint32_t s_txdesc[ETH_DESC_CNT][ETH_DS];  // TX descriptors
+static uint8_t s_rxbuf[ETH_DESC_CNT][ETH_PKT_SIZE];       // RX ethernet buffers
+static uint8_t s_txbuf[ETH_DESC_CNT][ETH_PKT_SIZE];       // TX ethernet buffers
+static struct mg_tcpip_if *s_ifp;                         // MIP interface
+
+static uint16_t eth_read_phy(uint8_t addr, uint8_t reg) {
+  ETH->MACMDIOAR &= (0xF << 8);
+  ETH->MACMDIOAR |= ((uint32_t) addr << 21) | ((uint32_t) reg << 16) | 3 << 2;
+  ETH->MACMDIOAR |= MG_BIT(0);
+  while (ETH->MACMDIOAR & MG_BIT(0)) (void) 0;
+  return (uint16_t) ETH->MACMDIODR;
 }
 
-static uint32_t csumup(uint32_t sum, const void *buf, size_t len) {
-  const uint8_t *p = (const uint8_t *) buf;
-  for (size_t i = 0; i < len; i++) sum += i & 1 ? p[i] : (uint32_t) (p[i] << 8);
-  return sum;
+static void eth_write_phy(uint8_t addr, uint8_t reg, uint16_t val) {
+  ETH->MACMDIODR = val;
+  ETH->MACMDIOAR &= (0xF << 8);
+  ETH->MACMDIOAR |= ((uint32_t) addr << 21) | ((uint32_t) reg << 16) | 1 << 2;
+  ETH->MACMDIOAR |= MG_BIT(0);
+  while (ETH->MACMDIOAR & MG_BIT(0)) (void) 0;
 }
 
-static uint16_t csumfin(uint32_t sum) {
-  while (sum >> 16) sum = (sum & 0xffff) + (sum >> 16);
-  return mg_htons(~sum & 0xffff);
+static uint32_t get_hclk(void) {
+  struct rcc {
+    volatile uint32_t CR, HSICFGR, CRRCR, CSICFGR, CFGR, RESERVED1, D1CFGR,
+        D2CFGR, D3CFGR, RESERVED2, PLLCKSELR, PLLCFGR, PLL1DIVR, PLL1FRACR,
+        PLL2DIVR, PLL2FRACR, PLL3DIVR, PLL3FRACR, RESERVED3, D1CCIPR, D2CCIP1R,
+        D2CCIP2R, D3CCIPR, RESERVED4, CIER, CIFR, CICR, RESERVED5, BDCR, CSR,
+        RESERVED6, AHB3RSTR, AHB1RSTR, AHB2RSTR, AHB4RSTR, APB3RSTR, APB1LRSTR,
+        APB1HRSTR, APB2RSTR, APB4RSTR, GCR, RESERVED8, D3AMR, RESERVED11[9],
+        RSR, AHB3ENR, AHB1ENR, AHB2ENR, AHB4ENR, APB3ENR, APB1LENR, APB1HENR,
+        APB2ENR, APB4ENR, RESERVED12, AHB3LPENR, AHB1LPENR, AHB2LPENR,
+        AHB4LPENR, APB3LPENR, APB1LLPENR, APB1HLPENR, APB2LPENR, APB4LPENR,
+        RESERVED13[4];
+  } *rcc = ((struct rcc *) (0x40000000 + 0x18020000 + 0x4400));
+  uint32_t clk = 0, hsi = 64000000 /* 64 MHz */, hse = 8000000 /* 8MHz */,
+           csi = 4000000 /* 4MHz */;
+  unsigned int sel = (rcc->CFGR & (7 << 3)) >> 3;
+
+  if (sel == 1) {
+    clk = csi;
+  } else if (sel == 2) {
+    clk = hse;
+  } else if (sel == 3) {
+    uint32_t vco, m, n, p;
+    unsigned int src = (rcc->PLLCKSELR & (3 << 0)) >> 0;
+    m = ((rcc->PLLCKSELR & (0x3F << 4)) >> 4);
+    n = ((rcc->PLL1DIVR & (0x1FF << 0)) >> 0) + 1 +
+        ((rcc->PLLCFGR & MG_BIT(0)) ? 1 : 0);  // round-up in fractional mode
+    p = ((rcc->PLL1DIVR & (0x7F << 9)) >> 9) + 1;
+    if (src == 1) {
+      clk = csi;
+    } else if (src == 2) {
+      clk = hse;
+    } else {
+      clk = hsi;
+      clk >>= ((rcc->CR & 3) >> 3);
+    }
+    vco = (uint32_t) ((uint64_t) clk * n / m);
+    clk = vco / p;
+  } else {
+    clk = hsi;
+    clk >>= ((rcc->CR & 3) >> 3);
+  }
+  const uint8_t cptab[12] = {1, 2, 3, 4, 6, 7, 8, 9};  // log2(div)
+  uint32_t d1cpre = (rcc->D1CFGR & (0x0F << 8)) >> 8;
+  if (d1cpre >= 8) clk >>= cptab[d1cpre - 8];
+  MG_DEBUG(("D1 CLK: %u", clk));
+  uint32_t hpre = (rcc->D1CFGR & (0x0F << 0)) >> 0;
+  if (hpre < 8) return clk;
+  return ((uint32_t) clk) >> cptab[hpre - 8];
+}
+
+//  Guess CR from AHB1 clock. MDC clock is generated from the ETH peripheral
+//  clock (AHB1); as per 802.3, it must not exceed 2. As the AHB clock can
+//  be derived from HSI or CSI (internal RC) clocks, and those can go above
+//  specs, the datasheets specify a range of frequencies and activate one of a
+//  series of dividers to keep the MDC clock safely below 2.5MHz. We guess a
+//  divider setting based on HCLK with some drift. If the user uses a different
+//  clock from our defaults, needs to set the macros on top. Valid for
+//  STM32H74xxx/75xxx (58.11.4)(4.5% worst case drift)(CSI clock has a 7.5 %
+//  worst case drift @ max temp)
+static int guess_mdc_cr(void) {
+  const uint8_t crs[] = {2, 3, 0, 1, 4, 5};  // ETH->MACMDIOAR::CR values
+  const uint8_t div[] = {16, 26, 42, 62, 102, 124};  // Respective HCLK dividers
+  uint32_t hclk = get_hclk();                        // Guess system HCLK
+  int result = -1;                                   // Invalid CR value
+  for (int i = 0; i < 6; i++) {
+    if (hclk / div[i] <= 2375000UL /* 2.5MHz - 5% */) {
+      result = crs[i];
+      break;
+    }
+  }
+  if (result < 0) MG_ERROR(("HCLK too high"));
+  MG_DEBUG(("HCLK: %u, CR: %d", hclk, result));
+  return result;
 }
 
-static uint16_t ipcsum(const void *buf, size_t len) {
-  uint32_t sum = csumup(0, buf, len);
-  return csumfin(sum);
-}
+static bool mg_tcpip_driver_stm32h_init(struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_driver_stm32h_data *d =
+      (struct mg_tcpip_driver_stm32h_data *) ifp->driver_data;
+  s_ifp = ifp;
+  uint8_t phy_addr = d == NULL ? 0 : d->phy_addr;
+  uint8_t phy_conf = d == NULL ? MG_PHY_CLOCKS_MAC : d->phy_conf;
 
-// ARP cache is organised as a doubly linked list. A successful cache lookup
-// moves an entry to the head of the list. New entries are added by replacing
-// the last entry in the list with a new IP/MAC.
-// ARP cache format: | prev | next | Entry0 | Entry1 | .... | EntryN |
-// ARP entry format: | prev | next | IP (4bytes) | MAC (6bytes) |
-// prev and next are 1-byte offsets in the cache, so cache size is max 256 bytes
-// ARP entry size is 12 bytes
-static void arp_cache_init(uint8_t *p, int n, int size) {
-  for (int i = 0; i < n; i++) p[2 + i * size] = (uint8_t) (2 + (i - 1) * size);
-  for (int i = 0; i < n; i++) p[3 + i * size] = (uint8_t) (2 + (i + 1) * size);
-  p[0] = p[2] = (uint8_t) (2 + (n - 1) * size);
-  p[1] = p[3 + (n - 1) * size] = 2;
-}
+  // Init RX descriptors
+  for (int i = 0; i < ETH_DESC_CNT; i++) {
+    s_rxdesc[i][0] = (uint32_t) (uintptr_t) s_rxbuf[i];  // Point to data buffer
+    s_rxdesc[i][3] = MG_BIT(31) | MG_BIT(30) | MG_BIT(24);  // OWN, IOC, BUF1V
+  }
 
-#if 0
-static inline void arp_cache_dump(const uint8_t *p) {
-  MG_INFO(("ARP cache:"));
-  for (uint8_t i = 0, j = p[1]; i < MIP_ARP_ENTRIES; i++, j = p[j + 1]) {
-    MG_INFO(("  %I -> %A", 4, &p[j + 2], &p[j + 6]));
+  // Init TX descriptors
+  for (int i = 0; i < ETH_DESC_CNT; i++) {
+    s_txdesc[i][0] = (uint32_t) (uintptr_t) s_txbuf[i];  // Buf pointer
   }
-}
-#endif
 
-static const uint8_t bcastmac[6] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};
+  ETH->DMAMR |= MG_BIT(0);                         // Software reset
+  while ((ETH->DMAMR & MG_BIT(0)) != 0) (void) 0;  // Wait until done
 
-static uint8_t *arp_cache_find(struct mip_if *ifp, uint32_t ip) {
-  uint8_t *p = ifp->arp_cache;
-  if (ip == 0) return NULL;
-  // use broadcast MAC for local and global broadcast IP
-  if (ip == 0xffffffffU || ip == (ifp->ip | ~ifp->mask))
-    return (uint8_t *) bcastmac;
-  for (uint8_t i = 0, j = p[1]; i < MIP_ARP_ENTRIES; i++, j = p[j + 1]) {
-    if (memcmp(p + j + 2, &ip, sizeof(ip)) == 0) {
-      p[1] = j, p[0] = p[j];  // Found entry! Point list head to us
-      // MG_DEBUG(("ARP find: %I @ %A", 4, &ip, &p[j + 6]));
-      return p + j + 6;  // And return MAC address
-    }
-  }
-  return NULL;
-}
+  // Set MDC clock divider. If user told us the value, use it. Otherwise, guess
+  int cr = (d == NULL || d->mdc_cr < 0) ? guess_mdc_cr() : d->mdc_cr;
+  ETH->MACMDIOAR = ((uint32_t) cr & 0xF) << 8;
+
+  // NOTE(scaprile): We do not use timing facilities so the DMA engine does not
+  // re-write buffer address
+  ETH->DMAMR = 0 << 16;        // use interrupt mode 0 (58.8.1) (reset value)
+  ETH->DMASBMR |= MG_BIT(12);  // AAL NOTE(scaprile): is this actually needed
+  ETH->MACIER = 0;  // Do not enable additional irq sources (reset value)
+  ETH->MACTFCR = MG_BIT(7);  // Disable zero-quanta pause
+  // ETH->MACPFR = MG_BIT(31);  // Receive all
+  struct mg_phy phy = {eth_read_phy, eth_write_phy};
+  mg_phy_init(&phy, phy_addr, phy_conf);
+  ETH->DMACRDLAR =
+      (uint32_t) (uintptr_t) s_rxdesc;  // RX descriptors start address
+  ETH->DMACRDRLR = ETH_DESC_CNT - 1;    // ring length
+  ETH->DMACRDTPR =
+      (uint32_t) (uintptr_t) &s_rxdesc[ETH_DESC_CNT -
+                                       1];  // last valid descriptor address
+  ETH->DMACTDLAR =
+      (uint32_t) (uintptr_t) s_txdesc;  // TX descriptors start address
+  ETH->DMACTDRLR = ETH_DESC_CNT - 1;    // ring length
+  ETH->DMACTDTPR =
+      (uint32_t) (uintptr_t) s_txdesc;  // first available descriptor address
+  ETH->DMACCR = 0;  // DSL = 0 (contiguous descriptor table) (reset value)
+  ETH->DMACIER = MG_BIT(6) | MG_BIT(15);  // RIE, NIE
+  ETH->MACCR = MG_BIT(0) | MG_BIT(1) | MG_BIT(13) | MG_BIT(14) |
+               MG_BIT(15);     // RE, TE, Duplex, Fast, Reserved
+  ETH->MTLTQOMR |= MG_BIT(1);  // TSF
+  ETH->MTLRQOMR |= MG_BIT(5);  // RSF
+  ETH->DMACTCR |= MG_BIT(0);   // ST
+  ETH->DMACRCR |= MG_BIT(0);   // SR
 
-static void arp_cache_add(struct mip_if *ifp, uint32_t ip, uint8_t mac[6]) {
-  uint8_t *p = ifp->arp_cache;
-  if (ip == 0 || ip == ~0U) return;             // Bad IP
-  if (arp_cache_find(ifp, ip) != NULL) return;  // Already exists, do nothing
-  memcpy(p + p[0] + 2, &ip, sizeof(ip));  // Replace last entry: IP address
-  memcpy(p + p[0] + 6, mac, 6);           // And MAC address
-  p[1] = p[0], p[0] = p[p[1]];            // Point list head to us
-  MG_DEBUG(("ARP cache: added %I @ %A", 4, &ip, mac));
+  // MAC address filtering
+  ETH->MACA0HR = ((uint32_t) ifp->mac[5] << 8U) | ifp->mac[4];
+  ETH->MACA0LR = (uint32_t) (ifp->mac[3] << 24) |
+                 ((uint32_t) ifp->mac[2] << 16) |
+                 ((uint32_t) ifp->mac[1] << 8) | ifp->mac[0];
+  return true;
 }
 
-static size_t ether_output(struct mip_if *ifp, size_t len) {
-  // size_t min = 64;  // Pad short frames to 64 bytes (minimum Ethernet size)
-  // if (len < min) memset(ifp->tx.ptr + len, 0, min - len), len = min;
-  // mg_hexdump(ifp->tx.ptr, len);
-  return ifp->driver->tx(ifp->tx.ptr, len, ifp);
+static uint32_t s_txno;
+static size_t mg_tcpip_driver_stm32h_tx(const void *buf, size_t len,
+                                        struct mg_tcpip_if *ifp) {
+  if (len > sizeof(s_txbuf[s_txno])) {
+    MG_ERROR(("Frame too big, %ld", (long) len));
+    len = 0;  // Frame is too big
+  } else if ((s_txdesc[s_txno][3] & MG_BIT(31))) {
+    ifp->nerr++;
+    MG_ERROR(("No free descriptors: %u %08X %08X %08X", s_txno,
+              s_txdesc[s_txno][3], ETH->DMACSR, ETH->DMACTCR));
+    for (int i = 0; i < ETH_DESC_CNT; i++) MG_ERROR(("%08X", s_txdesc[i][3]));
+    len = 0;  // All descriptors are busy, fail
+  } else {
+    memcpy(s_txbuf[s_txno], buf, len);              // Copy data
+    s_txdesc[s_txno][2] = (uint32_t) len;           // Set data len
+    s_txdesc[s_txno][3] = MG_BIT(28) | MG_BIT(29);  // FD, LD
+    s_txdesc[s_txno][3] |= MG_BIT(31);  // Set OWN bit - let DMA take over
+    if (++s_txno >= ETH_DESC_CNT) s_txno = 0;
+  }
+  ETH->DMACSR |= MG_BIT(2) | MG_BIT(1);  // Clear any prior TBU, TPS
+  ETH->DMACTDTPR = (uint32_t) (uintptr_t) &s_txdesc[s_txno];  // and resume
+  return len;
+  (void) ifp;
 }
 
-static void arp_ask(struct mip_if *ifp, uint32_t ip) {
-  struct eth *eth = (struct eth *) ifp->tx.ptr;
-  struct arp *arp = (struct arp *) (eth + 1);
-  memset(eth->dst, 255, sizeof(eth->dst));
-  memcpy(eth->src, ifp->mac, sizeof(eth->src));
-  eth->type = mg_htons(0x806);
-  memset(arp, 0, sizeof(*arp));
-  arp->fmt = mg_htons(1), arp->pro = mg_htons(0x800), arp->hlen = 6,
-  arp->plen = 4;
-  arp->op = mg_htons(1), arp->tpa = ip, arp->spa = ifp->ip;
-  memcpy(arp->sha, ifp->mac, sizeof(arp->sha));
-  ether_output(ifp, PDIFF(eth, arp + 1));
+static bool mg_tcpip_driver_stm32h_up(struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_driver_stm32h_data *d =
+      (struct mg_tcpip_driver_stm32h_data *) ifp->driver_data;
+  uint8_t phy_addr = d == NULL ? 0 : d->phy_addr;
+  uint8_t speed = MG_PHY_SPEED_10M;
+  bool up = false, full_duplex = false;
+  struct mg_phy phy = {eth_read_phy, eth_write_phy};
+  up = mg_phy_up(&phy, phy_addr, &full_duplex, &speed);
+  if ((ifp->state == MG_TCPIP_STATE_DOWN) && up) {  // link state just went up
+    // tmp = reg with flags set to the most likely situation: 100M full-duplex
+    // if(link is slow or half) set flags otherwise
+    // reg = tmp
+    uint32_t maccr = ETH->MACCR | MG_BIT(14) | MG_BIT(13);  // 100M, Full-duplex
+    if (speed == MG_PHY_SPEED_10M) maccr &= ~MG_BIT(14);    // 10M
+    if (full_duplex == false) maccr &= ~MG_BIT(13);         // Half-duplex
+    ETH->MACCR = maccr;  // IRQ handler does not fiddle with this register
+    MG_DEBUG(("Link is %uM %s-duplex", maccr & MG_BIT(14) ? 100 : 10,
+              maccr & MG_BIT(13) ? "full" : "half"));
+  }
+  return up;
 }
 
-static void onstatechange(struct mip_if *ifp) {
-  if (ifp->state == MIP_STATE_READY) {
-    MG_INFO(("READY, IP: %I", 4, &ifp->ip));
-    MG_INFO(("       GW: %I", 4, &ifp->gw));
-    if (ifp->lease_expire > ifp->now) {
-      MG_INFO(
-          ("       Lease: %lld sec", (ifp->lease_expire - ifp->now) / 1000));
+void ETH_IRQHandler(void);
+static uint32_t s_rxno;
+void ETH_IRQHandler(void) {
+  if (ETH->DMACSR & MG_BIT(6)) {           // Frame received, loop
+    ETH->DMACSR = MG_BIT(15) | MG_BIT(6);  // Clear flag
+    for (uint32_t i = 0; i < 10; i++) {  // read as they arrive but not forever
+      if (s_rxdesc[s_rxno][3] & MG_BIT(31)) break;  // exit when done
+      if (((s_rxdesc[s_rxno][3] & (MG_BIT(28) | MG_BIT(29))) ==
+           (MG_BIT(28) | MG_BIT(29))) &&
+          !(s_rxdesc[s_rxno][3] & MG_BIT(15))) {  // skip partial/errored frames
+        uint32_t len = s_rxdesc[s_rxno][3] & (MG_BIT(15) - 1);
+        // MG_DEBUG(("%lx %lu %lx %08lx", s_rxno, len, s_rxdesc[s_rxno][3],
+        // ETH->DMACSR));
+        mg_tcpip_qwrite(s_rxbuf[s_rxno], len > 4 ? len - 4 : len, s_ifp);
+      }
+      s_rxdesc[s_rxno][3] =
+          MG_BIT(31) | MG_BIT(30) | MG_BIT(24);  // OWN, IOC, BUF1V
+      if (++s_rxno >= ETH_DESC_CNT) s_rxno = 0;
     }
-    arp_ask(ifp, ifp->gw);
-  } else if (ifp->state == MIP_STATE_UP) {
-    MG_ERROR(("Link up"));
-  } else if (ifp->state == MIP_STATE_DOWN) {
-    MG_ERROR(("Link down"));
   }
+  ETH->DMACSR =
+      MG_BIT(7) | MG_BIT(8);  // Clear possible RBU RPS while processing
+  ETH->DMACRDTPR =
+      (uint32_t) (uintptr_t) &s_rxdesc[ETH_DESC_CNT - 1];  // and resume RX
 }
 
-static struct ip *tx_ip(struct mip_if *ifp, uint8_t proto, uint32_t ip_src,
-                        uint32_t ip_dst, size_t plen) {
-  struct eth *eth = (struct eth *) ifp->tx.ptr;
-  struct ip *ip = (struct ip *) (eth + 1);
-  uint8_t *mac = arp_cache_find(ifp, ip_dst);  // Dst IP in ARP cache ?
-  if (!mac && ((ip_dst & ifp->mask) == (ifp->ip & ifp->mask)))
-    arp_ask(ifp, ip_dst);                             // Same net, lookup
-  if (!mac) mac = arp_cache_find(ifp, ifp->gw);       // Use gateway MAC
-  if (!mac) arp_ask(ifp, ifp->gw);                    // Not found? lookup
-  if (mac) memcpy(eth->dst, mac, sizeof(eth->dst));   // Found? Use it
-  if (!mac) memset(eth->dst, 255, sizeof(eth->dst));  // No? Use broadcast
-  memcpy(eth->src, ifp->mac, sizeof(eth->src));       // TODO(cpq): ARP lookup
-  eth->type = mg_htons(0x800);
-  memset(ip, 0, sizeof(*ip));
-  ip->ver = 0x45;   // Version 4, header length 5 words
-  ip->frag = 0x40;  // Don't fragment
-  ip->len = mg_htons((uint16_t) (sizeof(*ip) + plen));
-  ip->ttl = 64;
-  ip->proto = proto;
-  ip->src = ip_src;
-  ip->dst = ip_dst;
-  ip->csum = ipcsum(ip, sizeof(*ip));
-  return ip;
-}
+struct mg_tcpip_driver mg_tcpip_driver_stm32h = {
+    mg_tcpip_driver_stm32h_init, mg_tcpip_driver_stm32h_tx, NULL,
+    mg_tcpip_driver_stm32h_up};
+#endif
 
-static void tx_udp(struct mip_if *ifp, uint32_t ip_src, uint16_t sport,
-                   uint32_t ip_dst, uint16_t dport, const void *buf,
-                   size_t len) {
-  struct ip *ip = tx_ip(ifp, 17, ip_src, ip_dst, len + sizeof(struct udp));
-  struct udp *udp = (struct udp *) (ip + 1);
-  // MG_DEBUG(("UDP XX LEN %d %d", (int) len, (int) ifp->tx.len));
-  udp->sport = sport;
-  udp->dport = dport;
-  udp->len = mg_htons((uint16_t) (sizeof(*udp) + len));
-  udp->csum = 0;
-  uint32_t cs = csumup(0, udp, sizeof(*udp));
-  cs = csumup(cs, buf, len);
-  cs = csumup(cs, &ip->src, sizeof(ip->src));
-  cs = csumup(cs, &ip->dst, sizeof(ip->dst));
-  cs += (uint32_t) (ip->proto + sizeof(*udp) + len);
-  udp->csum = csumfin(cs);
-  memmove(udp + 1, buf, len);
-  // MG_DEBUG(("UDP LEN %d %d", (int) len, (int) ifp->frame_len));
-  ether_output(ifp, sizeof(struct eth) + sizeof(*ip) + sizeof(*udp) + len);
-}
+#ifdef MG_ENABLE_LINES
+#line 1 "src/drivers/tm4c.c"
+#endif
 
-static void tx_dhcp(struct mip_if *ifp, uint32_t src, uint32_t dst,
-                    uint8_t *opts, size_t optslen) {
-  struct dhcp dhcp = {1, 1, 6, 0, 0, 0, 0, 0, 0, 0, 0, {0}, 0, {0}};
-  dhcp.magic = mg_htonl(0x63825363);
-  memcpy(&dhcp.hwaddr, ifp->mac, sizeof(ifp->mac));
-  memcpy(&dhcp.xid, ifp->mac + 2, sizeof(dhcp.xid));
-  memcpy(&dhcp.options, opts, optslen);
-  tx_udp(ifp, src, mg_htons(68), dst, mg_htons(67), &dhcp, sizeof(dhcp));
-}
 
-static void tx_dhcp_request(struct mip_if *ifp, uint32_t src, uint32_t dst) {
-  uint8_t opts[] = {
-      53, 1, 3,                 // Type: DHCP request
-      55, 2, 1,   3,            // GW and mask
-      12, 3, 'm', 'i', 'p',     // Host name: "mip"
-      54, 4, 0,   0,   0,   0,  // DHCP server ID
-      50, 4, 0,   0,   0,   0,  // Requested IP
-      255                       // End of options
-  };
-  memcpy(opts + 14, &dst, sizeof(dst));
-  memcpy(opts + 20, &src, sizeof(src));
-  tx_dhcp(ifp, src, dst, opts, sizeof(opts));
-}
+#if MG_ENABLE_TCPIP && defined(MG_ENABLE_DRIVER_TM4C) && MG_ENABLE_DRIVER_TM4C
+struct tm4c_emac {
+  volatile uint32_t EMACCFG, EMACFRAMEFLTR, EMACHASHTBLH, EMACHASHTBLL,
+      EMACMIIADDR, EMACMIIDATA, EMACFLOWCTL, EMACVLANTG, RESERVED0, EMACSTATUS,
+      EMACRWUFF, EMACPMTCTLSTAT, RESERVED1[2], EMACRIS, EMACIM, EMACADDR0H,
+      EMACADDR0L, EMACADDR1H, EMACADDR1L, EMACADDR2H, EMACADDR2L, EMACADDR3H,
+      EMACADDR3L, RESERVED2[31], EMACWDOGTO, RESERVED3[8], EMACMMCCTRL,
+      EMACMMCRXRIS, EMACMMCTXRIS, EMACMMCRXIM, EMACMMCTXIM, RESERVED4,
+      EMACTXCNTGB, RESERVED5[12], EMACTXCNTSCOL, EMACTXCNTMCOL, RESERVED6[4],
+      EMACTXOCTCNTG, RESERVED7[6], EMACRXCNTGB, RESERVED8[4], EMACRXCNTCRCERR,
+      EMACRXCNTALGNERR, RESERVED9[10], EMACRXCNTGUNI, RESERVED10[239],
+      EMACVLNINCREP, EMACVLANHASH, RESERVED11[93], EMACTIMSTCTRL, EMACSUBSECINC,
+      EMACTIMSEC, EMACTIMNANO, EMACTIMSECU, EMACTIMNANOU, EMACTIMADD,
+      EMACTARGSEC, EMACTARGNANO, EMACHWORDSEC, EMACTIMSTAT, EMACPPSCTRL,
+      RESERVED12[12], EMACPPS0INTVL, EMACPPS0WIDTH, RESERVED13[294],
+      EMACDMABUSMOD, EMACTXPOLLD, EMACRXPOLLD, EMACRXDLADDR, EMACTXDLADDR,
+      EMACDMARIS, EMACDMAOPMODE, EMACDMAIM, EMACMFBOC, EMACRXINTWDT,
+      RESERVED14[8], EMACHOSTXDESC, EMACHOSRXDESC, EMACHOSTXBA, EMACHOSRXBA,
+      RESERVED15[218], EMACPP, EMACPC, EMACCC, RESERVED16, EMACEPHYRIS,
+      EMACEPHYIM, EMACEPHYIMSC;
+};
+#undef EMAC
+#define EMAC ((struct tm4c_emac *) (uintptr_t) 0x400EC000)
 
-static void tx_dhcp_discover(struct mip_if *ifp) {
-  uint8_t opts[] = {
-      53, 1, 1,     // Type: DHCP discover
-      55, 2, 1, 3,  // Parameters: ip, mask
-      255           // End of options
-  };
-  tx_dhcp(ifp, 0, 0xffffffff, opts, sizeof(opts));
-  MG_DEBUG(("DHCP discover sent"));
-}
+#define ETH_PKT_SIZE 1540  // Max frame size
+#define ETH_DESC_CNT 4     // Descriptors count
+#define ETH_DS 4           // Descriptor size (words)
 
-static void rx_arp(struct mip_if *ifp, struct pkt *pkt) {
-  if (pkt->arp->op == mg_htons(1) && pkt->arp->tpa == ifp->ip) {
-    // ARP request. Make a response, then send
-    MG_DEBUG(("ARP op %d %I: %I?", mg_ntohs(pkt->arp->op), 4, &pkt->arp->spa, 4,
-              &pkt->arp->tpa));
-    struct eth *eth = (struct eth *) ifp->tx.ptr;
-    struct arp *arp = (struct arp *) (eth + 1);
-    memcpy(eth->dst, pkt->eth->src, sizeof(eth->dst));
-    memcpy(eth->src, ifp->mac, sizeof(eth->src));
-    eth->type = mg_htons(0x806);
-    *arp = *pkt->arp;
-    arp->op = mg_htons(2);
-    memcpy(arp->tha, pkt->arp->sha, sizeof(pkt->arp->tha));
-    memcpy(arp->sha, ifp->mac, sizeof(pkt->arp->sha));
-    arp->tpa = pkt->arp->spa;
-    arp->spa = ifp->ip;
-    MG_DEBUG(("ARP response: we're %I", 4, &ifp->ip));
-    ether_output(ifp, PDIFF(eth, arp + 1));
-  } else if (pkt->arp->op == mg_htons(2)) {
-    if (memcmp(pkt->arp->tha, ifp->mac, sizeof(pkt->arp->tha)) != 0) return;
-    // MG_INFO(("ARP RESPONSE"));
-    arp_cache_add(ifp, pkt->arp->spa, pkt->arp->sha);
-  }
+static uint32_t s_rxdesc[ETH_DESC_CNT][ETH_DS];      // RX descriptors
+static uint32_t s_txdesc[ETH_DESC_CNT][ETH_DS];      // TX descriptors
+static uint8_t s_rxbuf[ETH_DESC_CNT][ETH_PKT_SIZE];  // RX ethernet buffers
+static uint8_t s_txbuf[ETH_DESC_CNT][ETH_PKT_SIZE];  // TX ethernet buffers
+static struct mg_tcpip_if *s_ifp;                    // MIP interface
+enum {
+  EPHY_ADDR = 0,
+  EPHYBMCR = 0,
+  EPHYBMSR = 1,
+  EPHYSTS = 16
+};  // PHY constants
+
+static inline void tm4cspin(volatile uint32_t count) {
+  while (count--) (void) 0;
 }
 
-static void rx_icmp(struct mip_if *ifp, struct pkt *pkt) {
-  // MG_DEBUG(("ICMP %d", (int) len));
-  if (pkt->icmp->type == 8 && pkt->ip != NULL && pkt->ip->dst == ifp->ip) {
-    size_t hlen = sizeof(struct eth) + sizeof(struct ip) + sizeof(struct icmp);
-    size_t space = ifp->tx.len - hlen, plen = pkt->pay.len;
-    if (plen > space) plen = space;
-    struct ip *ip =
-        tx_ip(ifp, 1, ifp->ip, pkt->ip->src, sizeof(struct icmp) + plen);
-    struct icmp *icmp = (struct icmp *) (ip + 1);
-    memset(icmp, 0, sizeof(*icmp));        // Set csum to 0
-    memcpy(icmp + 1, pkt->pay.ptr, plen);  // Copy RX payload to TX
-    icmp->csum = ipcsum(icmp, sizeof(*icmp) + plen);
-    ether_output(ifp, hlen + plen);
-  }
+static uint32_t emac_read_phy(uint8_t addr, uint8_t reg) {
+  EMAC->EMACMIIADDR &= (0xf << 2);
+  EMAC->EMACMIIADDR |= ((uint32_t) addr << 11) | ((uint32_t) reg << 6);
+  EMAC->EMACMIIADDR |= MG_BIT(0);
+  while (EMAC->EMACMIIADDR & MG_BIT(0)) tm4cspin(1);
+  return EMAC->EMACMIIDATA;
 }
 
-static void rx_dhcp_client(struct mip_if *ifp, struct pkt *pkt) {
-  uint32_t ip = 0, gw = 0, mask = 0;
-  uint8_t *p = pkt->dhcp->options,
-          *end = (uint8_t *) &pkt->raw.ptr[pkt->raw.len];
-  if (end < (uint8_t *) (pkt->dhcp + 1)) return;
-  while (p + 1 < end && p[0] != 255) {  // Parse options
-    if (p[0] == 1 && p[1] == sizeof(ifp->mask) && p + 6 < end) {  // Mask
-      memcpy(&mask, p + 2, sizeof(mask));
-    } else if (p[0] == 3 && p[1] == sizeof(ifp->gw) && p + 6 < end) {  // GW
-      memcpy(&gw, p + 2, sizeof(gw));
-      ip = pkt->dhcp->yiaddr;
-    } else if (p[0] == 51 && p[1] == 4 && p + 6 < end) {  // Lease
-      uint32_t lease = 0;
-      memcpy(&lease, p + 2, sizeof(lease));
-      ifp->lease_expire = ifp->now + mg_ntohl(lease) * 1000;
-    }
-    p += p[1] + 2;
-  }
-  if (ip && mask && gw && ifp->ip == 0) {
-    arp_cache_add(ifp, pkt->dhcp->siaddr, ((struct eth *) pkt->raw.ptr)->src);
-    ifp->ip = ip, ifp->gw = gw, ifp->mask = mask;
-    ifp->state = MIP_STATE_READY;
-    onstatechange(ifp);
-    tx_dhcp_request(ifp, ip, pkt->dhcp->siaddr);
-  }
+static void emac_write_phy(uint8_t addr, uint8_t reg, uint32_t val) {
+  EMAC->EMACMIIDATA = val;
+  EMAC->EMACMIIADDR &= (0xf << 2);
+  EMAC->EMACMIIADDR |= ((uint32_t) addr << 11) | ((uint32_t) reg << 6) | MG_BIT(1);
+  EMAC->EMACMIIADDR |= MG_BIT(0);
+  while (EMAC->EMACMIIADDR & MG_BIT(0)) tm4cspin(1);
 }
 
-// Simple DHCP server that assigns a next IP address: ifp->ip + 1
-static void rx_dhcp_server(struct mip_if *ifp, struct pkt *pkt) {
-  uint8_t op = 0, *p = pkt->dhcp->options,
-          *end = (uint8_t *) &pkt->raw.ptr[pkt->raw.len];
-  if (end < (uint8_t *) (pkt->dhcp + 1)) return;
-  // struct dhcp *req = pkt->dhcp;
-  struct dhcp res = {2, 1, 6, 0, 0, 0, 0, 0, 0, 0, 0, {0}, 0, {0}};
-  res.yiaddr = ifp->ip;
-  ((uint8_t *) (&res.yiaddr))[3]++;                // Offer our IP + 1
-  while (p + 1 < end && p[0] != 255) {             // Parse options
-    if (p[0] == 53 && p[1] == 1 && p + 2 < end) {  // Message type
-      op = p[2];
+static uint32_t get_sysclk(void) {
+  struct sysctl {
+    volatile uint32_t DONTCARE0[44], RSCLKCFG, DONTCARE1[43], PLLFREQ0,
+        PLLFREQ1;
+  } *sysctl = (struct sysctl *) 0x400FE000;
+  uint32_t clk = 0, piosc = 16000000 /* 16 MHz */, mosc = 25000000 /* 25MHz */;
+  if (sysctl->RSCLKCFG & (1 << 28)) {  // USEPLL
+    uint32_t fin, vco, mdiv, n, q, psysdiv;
+    uint32_t pllsrc = (sysctl->RSCLKCFG & (0xf << 24)) >> 24;
+    if (pllsrc == 0) {
+      clk = piosc;
+    } else if (pllsrc == 3) {
+      clk = mosc;
+    } else {
+      MG_ERROR(("Unsupported clock source"));
     }
-    p += p[1] + 2;
-  }
-  if (op == 1 || op == 3) {         // DHCP Discover or DHCP Request
-    uint8_t msg = op == 1 ? 2 : 5;  // Message type: DHCP OFFER or DHCP ACK
-    uint8_t opts[] = {
-        53, 1, msg,                 // Message type
-        1,  4, 0,   0,   0,   0,    // Subnet mask
-        54, 4, 0,   0,   0,   0,    // Server ID
-        12, 3, 'm', 'i', 'p',       // Host name: "mip"
-        51, 4, 255, 255, 255, 255,  // Lease time
-        255                         // End of options
-    };
-    memcpy(&res.hwaddr, pkt->dhcp->hwaddr, 6);
-    memcpy(opts + 5, &ifp->mask, sizeof(ifp->mask));
-    memcpy(opts + 11, &ifp->ip, sizeof(ifp->ip));
-    memcpy(&res.options, opts, sizeof(opts));
-    res.magic = pkt->dhcp->magic;
-    res.xid = pkt->dhcp->xid;
-    arp_cache_add(ifp, res.yiaddr, pkt->eth->src);
-    tx_udp(ifp, ifp->ip, mg_htons(67), op == 1 ? ~0U : res.yiaddr, mg_htons(68),
-           &res, sizeof(res));
+    q = (sysctl->PLLFREQ1 & (0x1f << 8)) >> 8;
+    n = (sysctl->PLLFREQ1 & (0x1f << 0)) >> 0;
+    fin = clk / ((q + 1) * (n + 1));
+    mdiv = (sysctl->PLLFREQ0 & (0x3ff << 0)) >>
+           0;  // mint + (mfrac / 1024); MFRAC not supported
+    psysdiv = (sysctl->RSCLKCFG & (0x3f << 0)) >> 0;
+    vco = (uint32_t) ((uint64_t) fin * mdiv);
+    return vco / (psysdiv + 1);
   }
-}
-
-static struct mg_connection *getpeer(struct mg_mgr *mgr, struct pkt *pkt,
-                                     bool lsn) {
-  struct mg_connection *c = NULL;
-  for (c = mgr->conns; c != NULL; c = c->next) {
-    if (c->is_udp && pkt->udp && c->loc.port == pkt->udp->dport) break;
-    if (!c->is_udp && pkt->tcp && c->loc.port == pkt->tcp->dport &&
-        lsn == c->is_listening && (lsn || c->rem.port == pkt->tcp->sport))
-      break;
+  uint32_t oscsrc = (sysctl->RSCLKCFG & (0xf << 20)) >> 20;
+  if (oscsrc == 0) {
+    clk = piosc;
+  } else if (oscsrc == 3) {
+    clk = mosc;
+  } else {
+    MG_ERROR(("Unsupported clock source"));
   }
-  return c;
+  uint32_t osysdiv = (sysctl->RSCLKCFG & (0xf << 16)) >> 16;
+  return clk / (osysdiv + 1);
 }
 
-static void rx_udp(struct mip_if *ifp, struct pkt *pkt) {
-  struct mg_connection *c = getpeer(ifp->mgr, pkt, true);
-  if (c == NULL) {
-    // No UDP listener on this port. Should send ICMP, but keep silent.
-  } else if (c != NULL) {
-    c->rem.port = pkt->udp->sport;
-    c->rem.ip = pkt->ip->src;
-    if (c->recv.len >= MG_MAX_RECV_SIZE) {
-      mg_error(c, "max_recv_buf_size reached");
-    } else if (c->recv.size - c->recv.len < pkt->pay.len &&
-               !mg_iobuf_resize(&c->recv, c->recv.len + pkt->pay.len)) {
-      mg_error(c, "oom");
-    } else {
-      memcpy(&c->recv.buf[c->recv.len], pkt->pay.ptr, pkt->pay.len);
-      c->recv.len += pkt->pay.len;
-      mg_call(c, MG_EV_READ, &pkt->pay.len);
+//  Guess CR from SYSCLK. MDC clock is generated from SYSCLK (AHB); as per
+//  802.3, it must not exceed 2.5MHz (also 20.4.2.6) As the AHB clock can be
+//  derived from the PIOSC (internal RC), and it can go above  specs, the
+//  datasheets specify a range of frequencies and activate one of a series of
+//  dividers to keep the MDC clock safely below 2.5MHz. We guess a divider
+//  setting based on SYSCLK with a +5% drift. If the user uses a different clock
+//  from our defaults, needs to set the macros on top Valid for TM4C129x (20.7)
+//  (4.5% worst case drift)
+// The PHY receives the main oscillator (MOSC) (20.3.1)
+static int guess_mdc_cr(void) {
+  uint8_t crs[] = {2, 3, 0, 1};      // EMAC->MACMIIAR::CR values
+  uint8_t div[] = {16, 26, 42, 62};  // Respective HCLK dividers
+  uint32_t sysclk = get_sysclk();    // Guess system SYSCLK
+  int result = -1;                   // Invalid CR value
+  if (sysclk < 25000000) {
+    MG_ERROR(("SYSCLK too low"));
+  } else {
+    for (int i = 0; i < 4; i++) {
+      if (sysclk / div[i] <= 2375000UL /* 2.5MHz - 5% */) {
+        result = crs[i];
+        break;
+      }
     }
+    if (result < 0) MG_ERROR(("SYSCLK too high"));
   }
+  MG_DEBUG(("SYSCLK: %u, CR: %d", sysclk, result));
+  return result;
 }
 
-static size_t tx_tcp(struct mip_if *ifp, uint32_t dst_ip, uint8_t flags,
-                     uint16_t sport, uint16_t dport, uint32_t seq, uint32_t ack,
-                     const void *buf, size_t len) {
-  struct ip *ip = tx_ip(ifp, 6, ifp->ip, dst_ip, sizeof(struct tcp) + len);
-  struct tcp *tcp = (struct tcp *) (ip + 1);
-  memset(tcp, 0, sizeof(*tcp));
-  if (buf != NULL && len) memmove(tcp + 1, buf, len);
-  tcp->sport = sport;
-  tcp->dport = dport;
-  tcp->seq = seq;
-  tcp->ack = ack;
-  tcp->flags = flags;
-  tcp->win = mg_htons(8192);
-  tcp->off = (uint8_t) (sizeof(*tcp) / 4 << 4);
-  uint32_t cs = 0;
-  uint16_t n = (uint16_t) (sizeof(*tcp) + len);
-  uint8_t pseudo[] = {0, ip->proto, (uint8_t) (n >> 8), (uint8_t) (n & 255)};
-  cs = csumup(cs, tcp, n);
-  cs = csumup(cs, &ip->src, sizeof(ip->src));
-  cs = csumup(cs, &ip->dst, sizeof(ip->dst));
-  cs = csumup(cs, pseudo, sizeof(pseudo));
-  tcp->csum = csumfin(cs);
-  return ether_output(ifp, PDIFF(ifp->tx.ptr, tcp + 1) + len);
-}
+static bool mg_tcpip_driver_tm4c_init(struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_driver_tm4c_data *d =
+      (struct mg_tcpip_driver_tm4c_data *) ifp->driver_data;
+  s_ifp = ifp;
 
-static size_t tx_tcp_pkt(struct mip_if *ifp, struct pkt *pkt, uint8_t flags,
-                         uint32_t seq, const void *buf, size_t len) {
-  uint32_t delta = (pkt->tcp->flags & (TH_SYN | TH_FIN)) ? 1 : 0;
-  return tx_tcp(ifp, pkt->ip->src, flags, pkt->tcp->dport, pkt->tcp->sport, seq,
-                mg_htonl(mg_ntohl(pkt->tcp->seq) + delta), buf, len);
-}
+  // Init RX descriptors
+  for (int i = 0; i < ETH_DESC_CNT; i++) {
+    s_rxdesc[i][0] = MG_BIT(31);                            // Own
+    s_rxdesc[i][1] = sizeof(s_rxbuf[i]) | MG_BIT(14);       // 2nd address chained
+    s_rxdesc[i][2] = (uint32_t) (uintptr_t) s_rxbuf[i];  // Point to data buffer
+    s_rxdesc[i][3] =
+        (uint32_t) (uintptr_t) s_rxdesc[(i + 1) % ETH_DESC_CNT];  // Chain
+    // MG_DEBUG(("%d %p", i, s_rxdesc[i]));
+  }
 
-static void settmout(struct mg_connection *c, uint8_t type) {
-  struct mip_if *ifp = (struct mip_if *) c->mgr->priv;
-  struct connstate *s = (struct connstate *) (c + 1);
-  unsigned n = type == MIP_TTYPE_ACK ? MIP_TCP_ACK_MS : MIP_TCP_KEEPALIVE_MS;
-  s->timer = ifp->now + n;
-  s->ttype = type;
-  MG_VERBOSE(("%lu %d -> %llx", c->id, type, s->timer));
-}
+  // Init TX descriptors
+  for (int i = 0; i < ETH_DESC_CNT; i++) {
+    s_txdesc[i][2] = (uint32_t) (uintptr_t) s_txbuf[i];  // Buf pointer
+    s_txdesc[i][3] =
+        (uint32_t) (uintptr_t) s_txdesc[(i + 1) % ETH_DESC_CNT];  // Chain
+  }
 
-static struct mg_connection *accept_conn(struct mg_connection *lsn,
-                                         struct pkt *pkt) {
-  struct mg_connection *c = mg_alloc_conn(lsn->mgr);
-  struct connstate *s = (struct connstate *) (c + 1);
-  s->seq = mg_ntohl(pkt->tcp->ack), s->ack = mg_ntohl(pkt->tcp->seq);
-  settmout(c, MIP_TTYPE_KEEPALIVE);
-  c->rem.ip = pkt->ip->src;
-  c->rem.port = pkt->tcp->sport;
-  MG_DEBUG(
-      ("%lu accepted %I:%hu", c->id, 4, &c->rem.ip, mg_ntohs(c->rem.port)));
-  LIST_ADD_HEAD(struct mg_connection, &lsn->mgr->conns, c);
-  c->is_accepted = 1;
-  c->is_hexdumping = lsn->is_hexdumping;
-  c->pfn = lsn->pfn;
-  c->loc = lsn->loc;
-  c->pfn_data = lsn->pfn_data;
-  c->fn = lsn->fn;
-  c->fn_data = lsn->fn_data;
-  mg_call(c, MG_EV_OPEN, NULL);
-  mg_call(c, MG_EV_ACCEPT, NULL);
-  return c;
+  EMAC->EMACDMABUSMOD |= MG_BIT(0);                            // Software reset
+  while ((EMAC->EMACDMABUSMOD & MG_BIT(0)) != 0) tm4cspin(1);  // Wait until done
+
+  // Set MDC clock divider. If user told us the value, use it. Otherwise, guess
+  int cr = (d == NULL || d->mdc_cr < 0) ? guess_mdc_cr() : d->mdc_cr;
+  EMAC->EMACMIIADDR = ((uint32_t) cr & 0xf) << 2;
+
+  // NOTE(cpq): we do not use extended descriptor bit 7, and do not use
+  // hardware checksum. Therefore, descriptor size is 4, not 8
+  // EMAC->EMACDMABUSMOD = MG_BIT(13) | MG_BIT(16) | MG_BIT(22) | MG_BIT(23) | MG_BIT(25);
+  EMAC->EMACIM = MG_BIT(3) | MG_BIT(9);  // Mask timestamp & PMT IT
+  EMAC->EMACFLOWCTL = MG_BIT(7);      // Disable zero-quanta pause
+  // EMAC->EMACFRAMEFLTR = MG_BIT(31);   // Receive all
+  // EMAC->EMACPC defaults to internal PHY (EPHY) in MMI mode
+  emac_write_phy(EPHY_ADDR, EPHYBMCR, MG_BIT(15));  // Reset internal PHY (EPHY)
+  emac_write_phy(EPHY_ADDR, EPHYBMCR, MG_BIT(12));  // Set autonegotiation
+  EMAC->EMACRXDLADDR = (uint32_t) (uintptr_t) s_rxdesc;  // RX descriptors
+  EMAC->EMACTXDLADDR = (uint32_t) (uintptr_t) s_txdesc;  // TX descriptors
+  EMAC->EMACDMAIM = MG_BIT(6) | MG_BIT(16);                    // RIE, NIE
+  EMAC->EMACCFG = MG_BIT(2) | MG_BIT(3) | MG_BIT(11) | MG_BIT(14);   // RE, TE, Duplex, Fast
+  EMAC->EMACDMAOPMODE =
+      MG_BIT(1) | MG_BIT(13) | MG_BIT(21) | MG_BIT(25);  // SR, ST, TSF, RSF
+  EMAC->EMACADDR0H = ((uint32_t) ifp->mac[5] << 8U) | ifp->mac[4];
+  EMAC->EMACADDR0L = (uint32_t) (ifp->mac[3] << 24) |
+                     ((uint32_t) ifp->mac[2] << 16) |
+                     ((uint32_t) ifp->mac[1] << 8) | ifp->mac[0];
+  // NOTE(scaprile) There are 3 additional slots for filtering, disabled by
+  // default. This also applies to the STM32 driver (at least for F7)
+  return true;
 }
 
-long mg_io_send(struct mg_connection *c, const void *buf, size_t len) {
-  struct mip_if *ifp = (struct mip_if *) c->mgr->priv;
-  struct connstate *s = (struct connstate *) (c + 1);
-  size_t max_headers_len = 14 + 24 /* max IP */ + 60 /* max TCP */;
-  if (len + max_headers_len > ifp->tx.len) len = ifp->tx.len - max_headers_len;
-  if (tx_tcp(ifp, c->rem.ip, TH_PUSH | TH_ACK, c->loc.port, c->rem.port,
-             mg_htonl(s->seq), mg_htonl(s->ack), buf, len) > 0) {
-    s->seq += (uint32_t) len;
-    if (s->ttype == MIP_TTYPE_ACK) settmout(c, MIP_TTYPE_KEEPALIVE);
+static uint32_t s_txno;
+static size_t mg_tcpip_driver_tm4c_tx(const void *buf, size_t len,
+                                      struct mg_tcpip_if *ifp) {
+  if (len > sizeof(s_txbuf[s_txno])) {
+    MG_ERROR(("Frame too big, %ld", (long) len));
+    len = 0;  // fail
+  } else if ((s_txdesc[s_txno][0] & MG_BIT(31))) {
+    ifp->nerr++;
+    MG_ERROR(("No descriptors available"));
+    // printf("D0 %lx SR %lx\n", (long) s_txdesc[0][0], (long)
+    // EMAC->EMACDMARIS);
+    len = 0;  // fail
   } else {
-    return MG_IO_ERR;
+    memcpy(s_txbuf[s_txno], buf, len);     // Copy data
+    s_txdesc[s_txno][1] = (uint32_t) len;  // Set data len
+    s_txdesc[s_txno][0] =
+        MG_BIT(20) | MG_BIT(28) | MG_BIT(29) | MG_BIT(30);  // Chain,FS,LS,IC
+    s_txdesc[s_txno][0] |= MG_BIT(31);  // Set OWN bit - let DMA take over
+    if (++s_txno >= ETH_DESC_CNT) s_txno = 0;
   }
-  return (long) len;
+  EMAC->EMACDMARIS = MG_BIT(2) | MG_BIT(5);  // Clear any prior TU/UNF
+  EMAC->EMACTXPOLLD = 0;               // and resume
+  return len;
+  (void) ifp;
 }
 
-long mg_io_recv(struct mg_connection *c, void *buf, size_t len) {
-  struct connstate *s = (struct connstate *) (c + 1);
-  if (s->raw.len == 0) return MG_IO_WAIT;
-  if (len > s->raw.len) len = s->raw.len;
-  memcpy(buf, s->raw.buf, len);
-  mg_iobuf_del(&s->raw, 0, len);
-  MG_DEBUG(("%lu", len));
-  return (long) len;
+static bool mg_tcpip_driver_tm4c_up(struct mg_tcpip_if *ifp) {
+  uint32_t bmsr = emac_read_phy(EPHY_ADDR, EPHYBMSR);
+  bool up = (bmsr & MG_BIT(2)) ? 1 : 0;
+  if ((ifp->state == MG_TCPIP_STATE_DOWN) && up) {  // link state just went up
+    uint32_t sts = emac_read_phy(EPHY_ADDR, EPHYSTS);
+    // tmp = reg with flags set to the most likely situation: 100M full-duplex
+    // if(link is slow or half) set flags otherwise
+    // reg = tmp
+    uint32_t emaccfg = EMAC->EMACCFG | MG_BIT(14) | MG_BIT(11);  // 100M, Full-duplex
+    if (sts & MG_BIT(1)) emaccfg &= ~MG_BIT(14);                 // 10M
+    if ((sts & MG_BIT(2)) == 0) emaccfg &= ~MG_BIT(11);          // Half-duplex
+    EMAC->EMACCFG = emaccfg;  // IRQ handler does not fiddle with this register
+    MG_DEBUG(("Link is %uM %s-duplex", emaccfg & MG_BIT(14) ? 100 : 10,
+              emaccfg & MG_BIT(11) ? "full" : "half"));
+  }
+  return up;
 }
 
-static void read_conn(struct mg_connection *c, struct pkt *pkt) {
-  struct connstate *s = (struct connstate *) (c + 1);
-  struct mg_iobuf *io = c->is_tls ? &s->raw : &c->recv;
-  uint32_t seq = mg_ntohl(pkt->tcp->seq);
-  s->raw.align = c->recv.align;
-  if (pkt->tcp->flags & TH_FIN) {
-    s->ack = mg_htonl(pkt->tcp->seq) + 1, s->seq = mg_htonl(pkt->tcp->ack);
-    c->is_closing = 1;
-  } else if (pkt->pay.len == 0) {
-    // TODO(cpq): handle this peer's ACK
-  } else if (seq != s->ack) {
-    // TODO(cpq): peer sent us SEQ which we don't expect. Retransmit rather
-    // than close this connection
-    mg_error(c, "SEQ != ACK: %x %x", seq, s->ack);
-  } else if (io->size - io->len < pkt->pay.len &&
-             !mg_iobuf_resize(io, io->len + pkt->pay.len)) {
-    mg_error(c, "oom");
-  } else {
-    // Copy TCP payload into the IO buffer. If the connection is plain text, we
-    // copy to c->recv. If the connection is TLS, this data is encrypted,
-    // therefore we copy that encrypted data to the s->raw iobuffer instead,
-    // and then call mg_tls_recv() to decrypt it. NOTE: mg_tls_recv() will
-    // call back mg_io_recv() which grabs raw data from s->raw
-    memcpy(&io->buf[io->len], pkt->pay.ptr, pkt->pay.len);
-    io->len += pkt->pay.len;
-
-    MG_DEBUG(("%lu SEQ %x -> %x", c->id, mg_htonl(pkt->tcp->seq), s->ack));
-    // Advance ACK counter
-    s->ack = (uint32_t) (mg_htonl(pkt->tcp->seq) + pkt->pay.len);
-#if 0
-    // Send ACK immediately
-    MG_DEBUG(("  imm ACK", c->id, mg_htonl(pkt->tcp->seq), s->ack));
-    tx_tcp((struct mip_if *) c->mgr->priv, c->rem.ip, TH_ACK, c->loc.port,
-           c->rem.port, mg_htonl(s->seq), mg_htonl(s->ack), "", 0);
-#else
-    // if not already running, setup a timer to send an ACK later
-    if (s->ttype != MIP_TTYPE_ACK) settmout(c, MIP_TTYPE_ACK);
-#endif
-
-    if (c->is_tls) {
-      // TLS connection. Make room for decrypted data in c->recv
-      io = &c->recv;
-      if (io->size - io->len < pkt->pay.len &&
-          !mg_iobuf_resize(io, io->len + pkt->pay.len)) {
-        mg_error(c, "oom");
-      } else {
-        // Decrypt data directly into c->recv
-        long n = mg_tls_recv(c, &io->buf[io->len], io->size - io->len);
-        if (n == MG_IO_ERR) {
-          mg_error(c, "TLS recv error");
-        } else if (n > 0) {
-          // Decrypted successfully - trigger MG_EV_READ
-          io->len += (size_t) n;
-          mg_call(c, MG_EV_READ, &n);
-        }
+void EMAC0_IRQHandler(void);
+static uint32_t s_rxno;
+void EMAC0_IRQHandler(void) {
+  if (EMAC->EMACDMARIS & MG_BIT(6)) {        // Frame received, loop
+    EMAC->EMACDMARIS = MG_BIT(16) | MG_BIT(6);  // Clear flag
+    for (uint32_t i = 0; i < 10; i++) {   // read as they arrive but not forever
+      if (s_rxdesc[s_rxno][0] & MG_BIT(31)) break;  // exit when done
+      if (((s_rxdesc[s_rxno][0] & (MG_BIT(8) | MG_BIT(9))) == (MG_BIT(8) | MG_BIT(9))) &&
+          !(s_rxdesc[s_rxno][0] & MG_BIT(15))) {  // skip partial/errored frames
+        uint32_t len = ((s_rxdesc[s_rxno][0] >> 16) & (MG_BIT(14) - 1));
+        //  printf("%lx %lu %lx %.8lx\n", s_rxno, len, s_rxdesc[s_rxno][0],
+        //  EMAC->EMACDMARIS);
+        mg_tcpip_qwrite(s_rxbuf[s_rxno], len > 4 ? len - 4 : len, s_ifp);
       }
-    } else {
-      // Plain text connection, data is already in c->recv, trigger MG_EV_READ
-      mg_call(c, MG_EV_READ, &pkt->pay.len);
+      s_rxdesc[s_rxno][0] = MG_BIT(31);
+      if (++s_rxno >= ETH_DESC_CNT) s_rxno = 0;
     }
   }
+  EMAC->EMACDMARIS = MG_BIT(7);  // Clear possible RU while processing
+  EMAC->EMACRXPOLLD = 0;      // and resume RX
 }
 
-static void rx_tcp(struct mip_if *ifp, struct pkt *pkt) {
-  struct mg_connection *c = getpeer(ifp->mgr, pkt, false);
-  struct connstate *s = c == NULL ? NULL : (struct connstate *) (c + 1);
-#if 0
-  MG_INFO(("%lu %hhu %d", c ? c->id : 0, pkt->tcp->flags, (int) pkt->pay.len));
+struct mg_tcpip_driver mg_tcpip_driver_tm4c = {mg_tcpip_driver_tm4c_init,
+                                               mg_tcpip_driver_tm4c_tx, NULL,
+                                               mg_tcpip_driver_tm4c_up};
 #endif
-  if (c != NULL && c->is_connecting && pkt->tcp->flags & (TH_SYN | TH_ACK)) {
-    s->seq = mg_ntohl(pkt->tcp->ack), s->ack = mg_ntohl(pkt->tcp->seq) + 1;
-    tx_tcp_pkt(ifp, pkt, TH_ACK, pkt->tcp->ack, NULL, 0);
-    c->is_connecting = 0;             // Client connected
-    settmout(c, MIP_TTYPE_KEEPALIVE);
-    mg_call(c, MG_EV_CONNECT, NULL);  // Let user know
-  } else if (c != NULL && c->is_connecting) {
-    tx_tcp_pkt(ifp, pkt, TH_RST | TH_ACK, pkt->tcp->ack, NULL, 0);
-  } else if (c != NULL && pkt->tcp->flags & TH_RST) {
-    mg_error(c, "peer RST");  // RFC-1122 4.2.2.13
-  } else if (c != NULL) {
-#if 0
-    MG_DEBUG(("%lu %d %I:%hu -> %I:%hu", c->id, (int) pkt->raw.len,
-              4, &pkt->ip->src, mg_ntohs(pkt->tcp->sport),
-              4, &pkt->ip->dst, mg_ntohs(pkt->tcp->dport)));
-    mg_hexdump(pkt->pay.buf, pkt->pay.len);
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/drivers/w5500.c"
 #endif
-    s->tmiss = 0;                      // Reset missed keep-alive counter
-    if (s->ttype == MIP_TTYPE_KEEPALIVE) // Advance keep-alive timer
-      settmout(c, MIP_TTYPE_KEEPALIVE);  // unless a former ACK timeout is pending
-    read_conn(c, pkt);                 // Override timer with ACK timeout if needed
-  } else if ((c = getpeer(ifp->mgr, pkt, true)) == NULL) {
-    tx_tcp_pkt(ifp, pkt, TH_RST | TH_ACK, pkt->tcp->ack, NULL, 0);
-  } else if (pkt->tcp->flags & TH_RST) {
-    if (c->is_accepted) mg_error(c, "peer RST");  // RFC-1122 4.2.2.13
-    // ignore RST if not connected
-  } else if (pkt->tcp->flags & TH_SYN) {
-    // Use peer's source port as ISN, in order to recognise the handshake
-    uint32_t isn = mg_htonl((uint32_t) mg_ntohs(pkt->tcp->sport));
-    tx_tcp_pkt(ifp, pkt, TH_SYN | TH_ACK, isn, NULL, 0);
-  } else if (pkt->tcp->flags & TH_FIN) {
-    tx_tcp_pkt(ifp, pkt, TH_FIN | TH_ACK, pkt->tcp->ack, NULL, 0);
-  } else if (mg_htonl(pkt->tcp->ack) == mg_htons(pkt->tcp->sport) + 1U) {
-    accept_conn(c, pkt);
-  } else if (!c->is_accepted ) {  // no peer
-    tx_tcp_pkt(ifp, pkt, TH_RST | TH_ACK, pkt->tcp->ack, NULL, 0);
-  } else {
-    // MG_DEBUG(("dropped silently.."));
+
+
+#if MG_ENABLE_TCPIP && defined(MG_ENABLE_DRIVER_W5500) && MG_ENABLE_DRIVER_W5500
+
+enum { W5500_CR = 0, W5500_S0 = 1, W5500_TX0 = 2, W5500_RX0 = 3 };
+
+static void w5500_txn(struct mg_tcpip_spi *s, uint8_t block, uint16_t addr,
+                      bool wr, void *buf, size_t len) {
+  size_t i;
+  uint8_t *p = (uint8_t *) buf;
+  uint8_t cmd[] = {(uint8_t) (addr >> 8), (uint8_t) (addr & 255),
+                   (uint8_t) ((block << 3) | (wr ? 4 : 0))};
+  s->begin(s->spi);
+  for (i = 0; i < sizeof(cmd); i++) s->txn(s->spi, cmd[i]);
+  for (i = 0; i < len; i++) {
+    uint8_t r = s->txn(s->spi, p[i]);
+    if (!wr) p[i] = r;
   }
+  s->end(s->spi);
 }
 
-static void rx_ip(struct mip_if *ifp, struct pkt *pkt) {
-  //  MG_DEBUG(("IP %d", (int) pkt->pay.len));
-  if (pkt->ip->proto == 1) {
-    pkt->icmp = (struct icmp *) (pkt->ip + 1);
-    if (pkt->pay.len < sizeof(*pkt->icmp)) return;
-    mkpay(pkt, pkt->icmp + 1);
-    rx_icmp(ifp, pkt);
-  } else if (pkt->ip->proto == 17) {
-    pkt->udp = (struct udp *) (pkt->ip + 1);
-    if (pkt->pay.len < sizeof(*pkt->udp)) return;
-    mkpay(pkt, pkt->udp + 1);
-    if (pkt->udp->dport == mg_htons(68)) {
-      pkt->dhcp = (struct dhcp *) (pkt->udp + 1);
-      mkpay(pkt, pkt->dhcp + 1);
-      rx_dhcp_client(ifp, pkt);
-    } else if (ifp->enable_dhcp_server && pkt->udp->dport == mg_htons(67)) {
-      pkt->dhcp = (struct dhcp *) (pkt->udp + 1);
-      mkpay(pkt, pkt->dhcp + 1);
-      rx_dhcp_server(ifp, pkt);
-    } else {
-      rx_udp(ifp, pkt);
+// clang-format off
+static  void w5500_wn(struct mg_tcpip_spi *s, uint8_t block, uint16_t addr, void *buf, size_t len) { w5500_txn(s, block, addr, true, buf, len); }
+static  void w5500_w1(struct mg_tcpip_spi *s, uint8_t block, uint16_t addr, uint8_t val) { w5500_wn(s, block, addr, &val, 1); }
+static  void w5500_w2(struct mg_tcpip_spi *s, uint8_t block, uint16_t addr, uint16_t val) { uint8_t buf[2] = {(uint8_t) (val >> 8), (uint8_t) (val & 255)}; w5500_wn(s, block, addr, buf, sizeof(buf)); }
+static  void w5500_rn(struct mg_tcpip_spi *s, uint8_t block, uint16_t addr, void *buf, size_t len) { w5500_txn(s, block, addr, false, buf, len); }
+static  uint8_t w5500_r1(struct mg_tcpip_spi *s, uint8_t block, uint16_t addr) { uint8_t r = 0; w5500_rn(s, block, addr, &r, 1); return r; }
+static  uint16_t w5500_r2(struct mg_tcpip_spi *s, uint8_t block, uint16_t addr) { uint8_t buf[2] = {0, 0}; w5500_rn(s, block, addr, buf, sizeof(buf)); return (uint16_t) ((buf[0] << 8) | buf[1]); }
+// clang-format on
+
+static size_t w5500_rx(void *buf, size_t buflen, struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_spi *s = (struct mg_tcpip_spi *) ifp->driver_data;
+  uint16_t r = 0, n = 0, len = (uint16_t) buflen, n2;     // Read recv len
+  while ((n2 = w5500_r2(s, W5500_S0, 0x26)) > n) n = n2;  // Until it is stable
+  // printf("RSR: %d\n", (int) n);
+  if (n > 0) {
+    uint16_t ptr = w5500_r2(s, W5500_S0, 0x28);  // Get read pointer
+    n = w5500_r2(s, W5500_RX0, ptr);             // Read frame length
+    if (n <= len + 2 && n > 1) {
+      r = (uint16_t) (n - 2);
+      w5500_rn(s, W5500_RX0, (uint16_t) (ptr + 2), buf, r);
     }
-  } else if (pkt->ip->proto == 6) {
-    pkt->tcp = (struct tcp *) (pkt->ip + 1);
-    if (pkt->pay.len < sizeof(*pkt->tcp)) return;
-    mkpay(pkt, pkt->tcp + 1);
-    uint16_t iplen = mg_ntohs(pkt->ip->len);
-    uint16_t off = (uint16_t) (sizeof(*pkt->ip) + ((pkt->tcp->off >> 4) * 4U));
-    if (iplen >= off) pkt->pay.len = (size_t) (iplen - off);
-    rx_tcp(ifp, pkt);
+    w5500_w2(s, W5500_S0, 0x28, (uint16_t) (ptr + n));  // Advance read pointer
+    w5500_w1(s, W5500_S0, 1, 0x40);                     // Sock0 CR -> RECV
+    // printf("  RX_RD: tot=%u n=%u r=%u\n", n2, n, r);
   }
+  return r;
 }
 
-static void rx_ip6(struct mip_if *ifp, struct pkt *pkt) {
-  // MG_DEBUG(("IP %d", (int) len));
-  if (pkt->ip6->proto == 1 || pkt->ip6->proto == 58) {
-    pkt->icmp = (struct icmp *) (pkt->ip6 + 1);
-    if (pkt->pay.len < sizeof(*pkt->icmp)) return;
-    mkpay(pkt, pkt->icmp + 1);
-    rx_icmp(ifp, pkt);
-  } else if (pkt->ip6->proto == 17) {
-    pkt->udp = (struct udp *) (pkt->ip6 + 1);
-    if (pkt->pay.len < sizeof(*pkt->udp)) return;
-    // MG_DEBUG(("  UDP %u %u -> %u", len, mg_htons(udp->sport),
-    // mg_htons(udp->dport)));
-    mkpay(pkt, pkt->udp + 1);
+static size_t w5500_tx(const void *buf, size_t buflen,
+                       struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_spi *s = (struct mg_tcpip_spi *) ifp->driver_data;
+  uint16_t i, ptr, n = 0, len = (uint16_t) buflen;
+  while (n < len) n = w5500_r2(s, W5500_S0, 0x20);      // Wait for space
+  ptr = w5500_r2(s, W5500_S0, 0x24);                    // Get write pointer
+  w5500_wn(s, W5500_TX0, ptr, (void *) buf, len);       // Write data
+  w5500_w2(s, W5500_S0, 0x24, (uint16_t) (ptr + len));  // Advance write pointer
+  w5500_w1(s, W5500_S0, 1, 0x20);                       // Sock0 CR -> SEND
+  for (i = 0; i < 40; i++) {
+    uint8_t ir = w5500_r1(s, W5500_S0, 2);  // Read S0 IR
+    if (ir == 0) continue;
+    // printf("IR %d, len=%d, free=%d, ptr %d\n", ir, (int) len, (int) n, ptr);
+    w5500_w1(s, W5500_S0, 2, ir);  // Write S0 IR: clear it!
+    if (ir & 8) len = 0;           // Timeout. Report error
+    if (ir & (16 | 8)) break;      // Stop on SEND_OK or timeout
   }
+  return len;
 }
 
-static void mip_rx(struct mip_if *ifp, void *buf, size_t len) {
-  const uint8_t broadcast[] = {255, 255, 255, 255, 255, 255};
-  struct pkt pkt;
-  memset(&pkt, 0, sizeof(pkt));
-  pkt.raw.ptr = (char *) buf;
-  pkt.raw.len = len;
-  pkt.eth = (struct eth *) buf;
-  if (pkt.raw.len < sizeof(*pkt.eth)) return;  // Truncated - runt?
-  if (memcmp(pkt.eth->dst, ifp->mac, sizeof(pkt.eth->dst)) != 0 &&
-      memcmp(pkt.eth->dst, broadcast, sizeof(pkt.eth->dst)) != 0) {
-    // Not for us. Drop silently
-  } else if (pkt.eth->type == mg_htons(0x806)) {
-    pkt.arp = (struct arp *) (pkt.eth + 1);
-    if (sizeof(*pkt.eth) + sizeof(*pkt.arp) > pkt.raw.len) return;  // Truncated
-    rx_arp(ifp, &pkt);
-  } else if (pkt.eth->type == mg_htons(0x86dd)) {
-    pkt.ip6 = (struct ip6 *) (pkt.eth + 1);
-    if (pkt.raw.len < sizeof(*pkt.eth) + sizeof(*pkt.ip6)) return;  // Truncated
-    if ((pkt.ip6->ver >> 4) != 0x6) return;                         // Not IP
-    mkpay(&pkt, pkt.ip6 + 1);
-    rx_ip6(ifp, &pkt);
-  } else if (pkt.eth->type == mg_htons(0x800)) {
-    pkt.ip = (struct ip *) (pkt.eth + 1);
-    if (pkt.raw.len < sizeof(*pkt.eth) + sizeof(*pkt.ip)) return;  // Truncated
-    // Truncate frame to what IP header tells us
-    if ((size_t) mg_ntohs(pkt.ip->len) + sizeof(struct eth) < pkt.raw.len) {
-      pkt.raw.len = (size_t) mg_ntohs(pkt.ip->len) + sizeof(struct eth);
-    }
-    if (pkt.raw.len < sizeof(*pkt.eth) + sizeof(*pkt.ip)) return;  // Truncated
-    if ((pkt.ip->ver >> 4) != 4) return;                           // Not IP
-    mkpay(&pkt, pkt.ip + 1);
-    rx_ip(ifp, &pkt);
-  } else {
-    MG_DEBUG(("  Unknown eth type %x", mg_htons(pkt.eth->type)));
+static bool w5500_init(struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_spi *s = (struct mg_tcpip_spi *) ifp->driver_data;
+  s->end(s->spi);
+  w5500_w1(s, W5500_CR, 0, 0x80);     // Reset chip: CR -> 0x80
+  w5500_w1(s, W5500_CR, 0x2e, 0);     // CR PHYCFGR -> reset
+  w5500_w1(s, W5500_CR, 0x2e, 0xf8);  // CR PHYCFGR -> set
+  // w5500_wn(s, W5500_CR, 9, s->mac, 6);      // Set source MAC
+  w5500_w1(s, W5500_S0, 0x1e, 16);          // Sock0 RX buf size
+  w5500_w1(s, W5500_S0, 0x1f, 16);          // Sock0 TX buf size
+  w5500_w1(s, W5500_S0, 0, 4);              // Sock0 MR -> MACRAW
+  w5500_w1(s, W5500_S0, 1, 1);              // Sock0 CR -> OPEN
+  return w5500_r1(s, W5500_S0, 3) == 0x42;  // Sock0 SR == MACRAW
+}
+
+static bool w5500_up(struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_spi *spi = (struct mg_tcpip_spi *) ifp->driver_data;
+  uint8_t phycfgr = w5500_r1(spi, W5500_CR, 0x2e);
+  return phycfgr & 1;  // Bit 0 of PHYCFGR is LNK (0 - down, 1 - up)
+}
+
+struct mg_tcpip_driver mg_tcpip_driver_w5500 = {w5500_init, w5500_tx, w5500_rx,
+                                                w5500_up};
+#endif
+
+#ifdef MG_ENABLE_LINES
+#line 1 "src/drivers/xmc.c"
+#endif
+
+
+#if MG_ENABLE_TCPIP && defined(MG_ENABLE_DRIVER_XMC) && MG_ENABLE_DRIVER_XMC
+
+struct ETH_GLOBAL_TypeDef {
+  volatile uint32_t MAC_CONFIGURATION, MAC_FRAME_FILTER, HASH_TABLE_HIGH,
+  HASH_TABLE_LOW, GMII_ADDRESS, GMII_DATA, FLOW_CONTROL, VLAN_TAG, VERSION,
+  DEBUG, REMOTE_WAKE_UP_FRAME_FILTER, PMT_CONTROL_STATUS, RESERVED[2],
+  INTERRUPT_STATUS, INTERRUPT_MASK, MAC_ADDRESS0_HIGH, MAC_ADDRESS0_LOW,
+  MAC_ADDRESS1_HIGH, MAC_ADDRESS1_LOW, MAC_ADDRESS2_HIGH, MAC_ADDRESS2_LOW,
+  MAC_ADDRESS3_HIGH, MAC_ADDRESS3_LOW, RESERVED1[40], MMC_CONTROL,
+  MMC_RECEIVE_INTERRUPT, MMC_TRANSMIT_INTERRUPT, MMC_RECEIVE_INTERRUPT_MASK,
+  MMC_TRANSMIT_INTERRUPT_MASK, TX_STATISTICS[26], RESERVED2,
+  RX_STATISTICS_1[26], RESERVED3[6], MMC_IPC_RECEIVE_INTERRUPT_MASK,
+  RESERVED4, MMC_IPC_RECEIVE_INTERRUPT, RESERVED5, RX_STATISTICS_2[30],
+  RESERVED7[286], TIMESTAMP_CONTROL, SUB_SECOND_INCREMENT,
+  SYSTEM_TIME_SECONDS, SYSTEM_TIME_NANOSECONDS,
+  SYSTEM_TIME_SECONDS_UPDATE, SYSTEM_TIME_NANOSECONDS_UPDATE,
+  TIMESTAMP_ADDEND, TARGET_TIME_SECONDS, TARGET_TIME_NANOSECONDS,
+  SYSTEM_TIME_HIGHER_WORD_SECONDS, TIMESTAMP_STATUS,
+  PPS_CONTROL, RESERVED8[564], BUS_MODE, TRANSMIT_POLL_DEMAND,
+  RECEIVE_POLL_DEMAND, RECEIVE_DESCRIPTOR_LIST_ADDRESS,
+  TRANSMIT_DESCRIPTOR_LIST_ADDRESS, STATUS, OPERATION_MODE,
+  INTERRUPT_ENABLE, MISSED_FRAME_AND_BUFFER_OVERFLOW_COUNTER,
+  RECEIVE_INTERRUPT_WATCHDOG_TIMER, RESERVED9, AHB_STATUS,
+  RESERVED10[6], CURRENT_HOST_TRANSMIT_DESCRIPTOR,
+  CURRENT_HOST_RECEIVE_DESCRIPTOR, CURRENT_HOST_TRANSMIT_BUFFER_ADDRESS,
+  CURRENT_HOST_RECEIVE_BUFFER_ADDRESS, HW_FEATURE;
+};
+
+#undef ETH0
+#define ETH0  ((struct ETH_GLOBAL_TypeDef*) 0x5000C000UL)
+
+#define ETH_PKT_SIZE 1536 // Max frame size
+#define ETH_DESC_CNT 4     // Descriptors count
+#define ETH_DS 4           // Descriptor size (words)
+
+static uint8_t s_rxbuf[ETH_DESC_CNT][ETH_PKT_SIZE];
+static uint8_t s_txbuf[ETH_DESC_CNT][ETH_PKT_SIZE];
+static uint32_t s_rxdesc[ETH_DESC_CNT][ETH_DS];  // RX descriptors
+static uint32_t s_txdesc[ETH_DESC_CNT][ETH_DS];  // TX descriptors
+static uint8_t s_txno;                           // Current TX descriptor
+static uint8_t s_rxno;                           // Current RX descriptor
+
+static struct mg_tcpip_if *s_ifp;  // MIP interface
+enum { MG_PHY_ADDR = 0, MG_PHYREG_BCR = 0, MG_PHYREG_BSR = 1 };
+
+static uint16_t eth_read_phy(uint8_t addr, uint8_t reg) {
+  ETH0->GMII_ADDRESS = (ETH0->GMII_ADDRESS & 0x3c) |
+                        ((uint32_t)addr << 11) |
+                        ((uint32_t)reg << 6) | 1;
+  while ((ETH0->GMII_ADDRESS & 1) != 0) (void) 0;
+  return (uint16_t)(ETH0->GMII_DATA & 0xffff);
+}
+
+static void eth_write_phy(uint8_t addr, uint8_t reg, uint16_t val) {
+  ETH0->GMII_DATA  = val;
+  ETH0->GMII_ADDRESS = (ETH0->GMII_ADDRESS & 0x3c) |
+                        ((uint32_t)addr << 11) |
+                        ((uint32_t)reg << 6) | 3;
+  while ((ETH0->GMII_ADDRESS & 1) != 0) (void) 0;
+}
+
+static uint32_t get_clock_rate(struct mg_tcpip_driver_xmc_data *d) {
+  if (d->mdc_cr == -1) {
+    // assume ETH clock is 60MHz by default
+    // then according to 13.2.8.1, we need to set value 3
+    return 3;
   }
+
+  return d->mdc_cr;
 }
 
-static void mip_poll(struct mip_if *ifp, uint64_t uptime_ms) {
-  if (ifp == NULL || ifp->driver == NULL) return;
-  bool expired_1000ms = mg_timer_expired(&ifp->timer_1000ms, 1000, uptime_ms);
-  ifp->now = uptime_ms;
+static bool mg_tcpip_driver_xmc_init(struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_driver_xmc_data *d =
+      (struct mg_tcpip_driver_xmc_data *) ifp->driver_data;
+  s_ifp = ifp;
 
-  // Handle physical interface up/down status
-  if (expired_1000ms && ifp->driver->up) {
-    bool up = ifp->driver->up(ifp);
-    bool current = ifp->state != MIP_STATE_DOWN;
-    if (up != current) {
-      ifp->state = up == false               ? MIP_STATE_DOWN
-                   : ifp->enable_dhcp_client ? MIP_STATE_UP
-                                             : MIP_STATE_READY;
-      if (!up && ifp->enable_dhcp_client) ifp->ip = 0;
-      onstatechange(ifp);
+  // reset MAC
+  ETH0->BUS_MODE |= 1;
+  while (ETH0->BUS_MODE & 1) (void) 0;
+
+  // set clock rate
+  ETH0->GMII_ADDRESS = get_clock_rate(d) << 2;
+
+  // init phy
+  struct mg_phy phy = {eth_read_phy, eth_write_phy};
+  mg_phy_init(&phy, d->phy_addr, MG_PHY_CLOCKS_MAC);
+
+  // configure MAC: DO, DM, FES, TC
+  ETH0->MAC_CONFIGURATION = MG_BIT(13) | MG_BIT(11) | MG_BIT(14) | MG_BIT(24);
+
+  // set the MAC address
+  ETH0->MAC_ADDRESS0_HIGH = MG_U32(0, 0, ifp->mac[5], ifp->mac[4]);
+  ETH0->MAC_ADDRESS0_LOW = 
+        MG_U32(ifp->mac[3], ifp->mac[2], ifp->mac[1], ifp->mac[0]);
+
+  // Configure the receive filter
+  ETH0->MAC_FRAME_FILTER = MG_BIT(10) | MG_BIT(2); // HFP, HMC
+  // Disable flow control
+  ETH0->FLOW_CONTROL = 0;
+  // Enable store and forward mode
+  ETH0->OPERATION_MODE = MG_BIT(25) | MG_BIT(21); // RSF, TSF
+
+  // Configure DMA bus mode (AAL, USP, RPBL, PBL)
+  ETH0->BUS_MODE = MG_BIT(25) | MG_BIT(23) | (32 << 17) |  (32 << 8);
+
+  // init RX descriptors
+  for (int i = 0; i < ETH_DESC_CNT; i++) {
+    s_rxdesc[i][0] = MG_BIT(31); // OWN descriptor
+    s_rxdesc[i][1] = MG_BIT(14) | ETH_PKT_SIZE;
+    s_rxdesc[i][2] = (uint32_t) s_rxbuf[i];
+    if (i == ETH_DESC_CNT - 1) {
+      s_rxdesc[i][3] = (uint32_t) &s_rxdesc[0][0];
+    } else {
+      s_rxdesc[i][3] = (uint32_t) &s_rxdesc[i + 1][0];
     }
   }
-  if (ifp->state == MIP_STATE_DOWN) return;
-  // if (expired_1000ms) arp_cache_dump(ifp->arp_cache);
+  ETH0->RECEIVE_DESCRIPTOR_LIST_ADDRESS = (uint32_t) &s_rxdesc[0][0];
 
-  if (ifp->ip == 0 && expired_1000ms) {
-    tx_dhcp_discover(ifp);  // If IP not configured, send DHCP
-  } else if (ifp->enable_dhcp_client == false && expired_1000ms && ifp->gw &&
-             arp_cache_find(ifp, ifp->gw) == NULL) {
-    arp_ask(ifp, ifp->gw);  // If GW's MAC address in not in ARP cache
+  // init TX descriptors
+  for (int i = 0; i < ETH_DESC_CNT; i++) {
+    s_txdesc[i][0] = MG_BIT(30) | MG_BIT(20);
+    s_txdesc[i][2] = (uint32_t) s_txbuf[i];
+    if (i == ETH_DESC_CNT - 1) {
+      s_txdesc[i][3] = (uint32_t) &s_txdesc[0][0];
+    } else {
+      s_txdesc[i][3] = (uint32_t) &s_txdesc[i + 1][0];
+    }
   }
+  ETH0->TRANSMIT_DESCRIPTOR_LIST_ADDRESS = (uint32_t) &s_txdesc[0][0];
 
-  // Read data from the network
-  size_t len = ifp->driver->rx((void *) ifp->rx.ptr, ifp->rx.len, ifp);
-  mip_rx(ifp, (void *) ifp->rx.ptr, len);
-  qp_mark(QP_FRAMEDONE, (int) q_space(&ifp->queue));
+  // Clear interrupts
+  ETH0->STATUS = 0xFFFFFFFF;
 
-  // Process timeouts
-  for (struct mg_connection *c = ifp->mgr->conns; c != NULL; c = c->next) {
-    if (c->is_udp || c->is_listening) continue;
-    if (c->is_connecting || c->is_resolving) continue;
-    struct connstate *s = (struct connstate *) (c + 1);
-    if (uptime_ms > s->timer) {
-      if (s->ttype == MIP_TTYPE_ACK) {
-        MG_DEBUG(("%lu ack %x %x", c->id, s->seq, s->ack));
-        tx_tcp(ifp, c->rem.ip, TH_ACK, c->loc.port, c->rem.port,
-               mg_htonl(s->seq), mg_htonl(s->ack), "", 0);
-      } else {
-        if (s->tmiss++ > 2) {
-          mg_error(c, "keepalive");
-        } else {
-          MG_DEBUG(("%lu keepalive", c->id));
-          tx_tcp(ifp, c->rem.ip, TH_ACK, c->loc.port, c->rem.port,
-                 mg_htonl(s->seq - 1), mg_htonl(s->ack), "", 0);
-        }
-      }
-      settmout(c, MIP_TTYPE_KEEPALIVE);
-    }
-  }
-#ifdef MIP_QPROFILE
-  qp_log();
-#endif
+  // Disable MAC interrupts
+  ETH0->MMC_TRANSMIT_INTERRUPT_MASK = 0xFFFFFFFF;
+  ETH0->MMC_RECEIVE_INTERRUPT_MASK = 0xFFFFFFFF;
+  ETH0->MMC_IPC_RECEIVE_INTERRUPT_MASK = 0xFFFFFFFF;
+  ETH0->INTERRUPT_MASK = MG_BIT(9) | MG_BIT(3); // TSIM, PMTIM
+
+  //Enable interrupts (NIE, RIE, TIE)
+  ETH0->INTERRUPT_ENABLE = MG_BIT(16) | MG_BIT(6) | MG_BIT(0);
+
+  // Enable MAC transmission and reception (TE, RE)
+  ETH0->MAC_CONFIGURATION |= MG_BIT(3) | MG_BIT(2);
+  // Enable DMA transmission and reception (ST, SR)
+  ETH0->OPERATION_MODE |= MG_BIT(13) | MG_BIT(1);
+  return true;
 }
 
-// This function executes in interrupt context, thus it should copy data
-// somewhere fast. Note that newlib's malloc is not thread safe, thus use
-// our lock-free queue with preallocated buffer to copy data and return asap
-void mip_qwrite(void *buf, size_t len, struct mip_if *ifp) {
-  if (q_write(&ifp->queue, buf, len)) {
-    qp_mark(QP_FRAMEPUSHED, (int) q_space(&ifp->queue));
+static size_t mg_tcpip_driver_xmc_tx(const void *buf, size_t len,
+                                        struct mg_tcpip_if *ifp) {
+  if (len > sizeof(s_txbuf[s_txno])) {
+    MG_ERROR(("Frame too big, %ld", (long) len));
+    len = 0;  // Frame is too big
+  } else if ((s_txdesc[s_txno][0] & MG_BIT(31))) {
+    ifp->nerr++;
+    MG_ERROR(("No free descriptors"));
+    len = 0;  // All descriptors are busy, fail
   } else {
-    ifp->dropped++;
-    qp_mark(QP_FRAMEDROPPED, ifp->dropped);
-    MG_ERROR(("dropped %d", (int) len));
+    memcpy(s_txbuf[s_txno], buf, len);
+    s_txdesc[s_txno][1] = len;
+    // Table 13-19 Transmit Descriptor Word 0 (IC, LS, FS, TCH)
+    s_txdesc[s_txno][0] = MG_BIT(30) | MG_BIT(29) | MG_BIT(28) | MG_BIT(20);
+    s_txdesc[s_txno][0] |= MG_BIT(31);  // OWN bit: handle control to DMA
+    if (++s_txno >= ETH_DESC_CNT) s_txno = 0;
   }
-}
 
-size_t mip_qread(void *buf, struct mip_if *ifp) {
-  size_t len = q_read(&ifp->queue, buf);
-  qp_mark(QP_FRAMEPOPPED, (int) q_space(&ifp->queue));
+  // Resume processing
+  ETH0->STATUS = MG_BIT(2); // clear Transmit unavailable
+  ETH0->TRANSMIT_POLL_DEMAND = 0;
   return len;
 }
 
-size_t mip_driver_rx(void *buf, size_t len, struct mip_if *ifp) {
-  return mip_qread((void *) ifp->rx.ptr, ifp);
-  (void) len, (void) buf;
-}
+static bool mg_tcpip_driver_xmc_up(struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_driver_xmc_data *d =
+      (struct mg_tcpip_driver_xmc_data *) ifp->driver_data;
+  uint8_t speed = MG_PHY_SPEED_10M;
+  bool up = false, full_duplex = false;
+  struct mg_phy phy = {eth_read_phy, eth_write_phy};
+  up = mg_phy_up(&phy, d->phy_addr, &full_duplex, &speed);
+  if ((ifp->state == MG_TCPIP_STATE_DOWN) && up) {  // link state just went up
+    MG_DEBUG(("Link is %uM %s-duplex", speed == MG_PHY_SPEED_10M ? 10 : 100,
+              full_duplex ? "full" : "half"));
+  }
+  return up;
+}
+
+void ETH0_IRQHandler(void);
+void ETH0_IRQHandler(void) {
+  uint32_t irq_status = ETH0->STATUS;
+
+  // check if a frame was received
+  if (irq_status & MG_BIT(6)) {
+    for (uint8_t i = 0; i < ETH_DESC_CNT; i++) {
+      if ((s_rxdesc[s_rxno][0] & MG_BIT(31)) == 0) {
+        size_t len = (s_rxdesc[s_rxno][0] & 0x3fff0000) >> 16;
+        mg_tcpip_qwrite(s_rxbuf[s_rxno], len, s_ifp);
+        s_rxdesc[s_rxno][0] = MG_BIT(31);   // OWN bit: handle control to DMA
+        // Resume processing
+        ETH0->STATUS = MG_BIT(7) | MG_BIT(6); // clear RU and RI
+        ETH0->RECEIVE_POLL_DEMAND = 0;
+        if (++s_rxno >= ETH_DESC_CNT) s_rxno = 0;
+      }
+    }
+    ETH0->STATUS = MG_BIT(6);
+  }
 
-void mip_init(struct mg_mgr *mgr, struct mip_if *ifp) {
-  if (ifp->driver->init && !ifp->driver->init(ifp)) {
-    MG_ERROR(("driver init failed"));
-  } else {
-    size_t maxpktsize = 1540;
-    ifp->rx.ptr = (char *) calloc(1, maxpktsize), ifp->rx.len = maxpktsize;
-    ifp->tx.ptr = (char *) calloc(1, maxpktsize), ifp->tx.len = maxpktsize;
-    if (ifp->queue.len) ifp->queue.buf = (uint8_t *) calloc(1, ifp->queue.len);
-    ifp->timer_1000ms = mg_millis();
-    arp_cache_init(ifp->arp_cache, MIP_ARP_ENTRIES, 12);
-    mgr->priv = ifp;
-    ifp->mgr = mgr;
-    mgr->extraconnsize = sizeof(struct connstate);
-    if (ifp->ip == 0) ifp->enable_dhcp_client = true;
-#ifdef MIP_QPROFILE
-    qp_init();
-#endif
+  // clear Successful transmission interrupt
+  if (irq_status & 1) {
+    ETH0->STATUS = 1;
   }
-}
 
-void mip_free(struct mip_if *ifp) {
-  free((char *) ifp->rx.ptr);
-  free((char *) ifp->tx.ptr);
+  // clear normal interrupt
+  if (irq_status & MG_BIT(16)) {
+    ETH0->STATUS = MG_BIT(16);
+  }
 }
 
-int mg_mkpipe(struct mg_mgr *m, mg_event_handler_t fn, void *d, bool udp) {
-  (void) m, (void) fn, (void) d, (void) udp;
-  MG_ERROR(("Not implemented"));
-  return -1;
-}
+struct mg_tcpip_driver mg_tcpip_driver_xmc = {
+    mg_tcpip_driver_xmc_init, mg_tcpip_driver_xmc_tx, NULL,
+    mg_tcpip_driver_xmc_up};
+#endif
 
-#if 0
-static uint16_t mkeport(void) {
-  uint16_t a = 0, b = mg_millis() & 0xffffU, c = MIP_ETHEMERAL_PORT;
-  mg_random(&a, sizeof(a));
-  c += (a ^ b) % (0xffffU - MIP_ETHEMERAL_PORT);
-  return c;
-}
+#ifdef MG_ENABLE_LINES
+#line 1 "src/drivers/xmc7.c"
 #endif
 
-void mg_connect_resolved(struct mg_connection *c) {
-  struct mip_if *ifp = (struct mip_if *) c->mgr->priv;
-  c->is_resolving = 0;
-  if (ifp->eport < MIP_ETHEMERAL_PORT) ifp->eport = MIP_ETHEMERAL_PORT;
-  c->loc.ip = ifp->ip;
-  c->loc.port = mg_htons(ifp->eport++);
-  MG_DEBUG(("%lu %I:%hu->%I:%hu", c->id, 4, &c->loc.ip, mg_ntohs(c->loc.port),
-            4, &c->rem.ip, mg_ntohs(c->rem.port)));
-  mg_call(c, MG_EV_RESOLVE, NULL);
-  if (c->is_udp) {
-    mg_call(c, MG_EV_CONNECT, NULL);
-  } else {
-    uint32_t isn = mg_htonl((uint32_t) mg_ntohs(c->loc.port));
-    tx_tcp(ifp, c->rem.ip, TH_SYN, c->loc.port, c->rem.port, isn, 0, NULL, 0);
-    c->is_connecting = 1;
-  }
-}
 
-bool mg_open_listener(struct mg_connection *c, const char *url) {
-  c->loc.port = mg_htons(mg_url_port(url));
-  return true;
-}
+#if MG_ENABLE_TCPIP && defined(MG_ENABLE_DRIVER_XMC7) && MG_ENABLE_DRIVER_XMC7
+
+struct ETH_Type {
+  volatile uint32_t CTL, STATUS, RESERVED[1022], NETWORK_CONTROL,
+      NETWORK_CONFIG, NETWORK_STATUS, USER_IO_REGISTER, DMA_CONFIG,
+      TRANSMIT_STATUS, RECEIVE_Q_PTR, TRANSMIT_Q_PTR, RECEIVE_STATUS,
+      INT_STATUS, INT_ENABLE, INT_DISABLE, INT_MASK, PHY_MANAGEMENT, PAUSE_TIME,
+      TX_PAUSE_QUANTUM, PBUF_TXCUTTHRU, PBUF_RXCUTTHRU, JUMBO_MAX_LENGTH,
+      EXTERNAL_FIFO_INTERFACE, RESERVED1, AXI_MAX_PIPELINE, RSC_CONTROL,
+      INT_MODERATION, SYS_WAKE_TIME, RESERVED2[7], HASH_BOTTOM, HASH_TOP,
+      SPEC_ADD1_BOTTOM, SPEC_ADD1_TOP, SPEC_ADD2_BOTTOM, SPEC_ADD2_TOP,
+      SPEC_ADD3_BOTTOM, SPEC_ADD3_TOP, SPEC_ADD4_BOTTOM, SPEC_ADD4_TOP,
+      SPEC_TYPE1, SPEC_TYPE2, SPEC_TYPE3, SPEC_TYPE4, WOL_REGISTER,
+      STRETCH_RATIO, STACKED_VLAN, TX_PFC_PAUSE, MASK_ADD1_BOTTOM,
+      MASK_ADD1_TOP, DMA_ADDR_OR_MASK, RX_PTP_UNICAST, TX_PTP_UNICAST,
+      TSU_NSEC_CMP, TSU_SEC_CMP, TSU_MSB_SEC_CMP, TSU_PTP_TX_MSB_SEC,
+      TSU_PTP_RX_MSB_SEC, TSU_PEER_TX_MSB_SEC, TSU_PEER_RX_MSB_SEC,
+      DPRAM_FILL_DBG, REVISION_REG, OCTETS_TXED_BOTTOM, OCTETS_TXED_TOP,
+      FRAMES_TXED_OK, BROADCAST_TXED, MULTICAST_TXED, PAUSE_FRAMES_TXED,
+      FRAMES_TXED_64, FRAMES_TXED_65, FRAMES_TXED_128, FRAMES_TXED_256,
+      FRAMES_TXED_512, FRAMES_TXED_1024, FRAMES_TXED_1519, TX_UNDERRUNS,
+      SINGLE_COLLISIONS, MULTIPLE_COLLISIONS, EXCESSIVE_COLLISIONS,
+      LATE_COLLISIONS, DEFERRED_FRAMES, CRS_ERRORS, OCTETS_RXED_BOTTOM,
+      OCTETS_RXED_TOP, FRAMES_RXED_OK, BROADCAST_RXED, MULTICAST_RXED,
+      PAUSE_FRAMES_RXED, FRAMES_RXED_64, FRAMES_RXED_65, FRAMES_RXED_128,
+      FRAMES_RXED_256, FRAMES_RXED_512, FRAMES_RXED_1024, FRAMES_RXED_1519,
+      UNDERSIZE_FRAMES, EXCESSIVE_RX_LENGTH, RX_JABBERS, FCS_ERRORS,
+      RX_LENGTH_ERRORS, RX_SYMBOL_ERRORS, ALIGNMENT_ERRORS, RX_RESOURCE_ERRORS,
+      RX_OVERRUNS, RX_IP_CK_ERRORS, RX_TCP_CK_ERRORS, RX_UDP_CK_ERRORS,
+      AUTO_FLUSHED_PKTS, RESERVED3, TSU_TIMER_INCR_SUB_NSEC, TSU_TIMER_MSB_SEC,
+      TSU_STROBE_MSB_SEC, TSU_STROBE_SEC, TSU_STROBE_NSEC, TSU_TIMER_SEC,
+      TSU_TIMER_NSEC, TSU_TIMER_ADJUST, TSU_TIMER_INCR, TSU_PTP_TX_SEC,
+      TSU_PTP_TX_NSEC, TSU_PTP_RX_SEC, TSU_PTP_RX_NSEC, TSU_PEER_TX_SEC,
+      TSU_PEER_TX_NSEC, TSU_PEER_RX_SEC, TSU_PEER_RX_NSEC, PCS_CONTROL,
+      PCS_STATUS, RESERVED4[2], PCS_AN_ADV, PCS_AN_LP_BASE, PCS_AN_EXP,
+      PCS_AN_NP_TX, PCS_AN_LP_NP, RESERVED5[6], PCS_AN_EXT_STATUS, RESERVED6[8],
+      TX_PAUSE_QUANTUM1, TX_PAUSE_QUANTUM2, TX_PAUSE_QUANTUM3, RESERVED7,
+      RX_LPI, RX_LPI_TIME, TX_LPI, TX_LPI_TIME, DESIGNCFG_DEBUG1,
+      DESIGNCFG_DEBUG2, DESIGNCFG_DEBUG3, DESIGNCFG_DEBUG4, DESIGNCFG_DEBUG5,
+      DESIGNCFG_DEBUG6, DESIGNCFG_DEBUG7, DESIGNCFG_DEBUG8, DESIGNCFG_DEBUG9,
+      DESIGNCFG_DEBUG10, RESERVED8[22], SPEC_ADD5_BOTTOM, SPEC_ADD5_TOP,
+      RESERVED9[60], SPEC_ADD36_BOTTOM, SPEC_ADD36_TOP, INT_Q1_STATUS,
+      INT_Q2_STATUS, INT_Q3_STATUS, RESERVED10[11], INT_Q15_STATUS, RESERVED11,
+      TRANSMIT_Q1_PTR, TRANSMIT_Q2_PTR, TRANSMIT_Q3_PTR, RESERVED12[11],
+      TRANSMIT_Q15_PTR, RESERVED13, RECEIVE_Q1_PTR, RECEIVE_Q2_PTR,
+      RECEIVE_Q3_PTR, RESERVED14[3], RECEIVE_Q7_PTR, RESERVED15,
+      DMA_RXBUF_SIZE_Q1, DMA_RXBUF_SIZE_Q2, DMA_RXBUF_SIZE_Q3, RESERVED16[3],
+      DMA_RXBUF_SIZE_Q7, CBS_CONTROL, CBS_IDLESLOPE_Q_A, CBS_IDLESLOPE_Q_B,
+      UPPER_TX_Q_BASE_ADDR, TX_BD_CONTROL, RX_BD_CONTROL, UPPER_RX_Q_BASE_ADDR,
+      RESERVED17[2], HIDDEN_REG0, HIDDEN_REG1, HIDDEN_REG2, HIDDEN_REG3,
+      RESERVED18[2], HIDDEN_REG4, HIDDEN_REG5;
+};
 
-static void write_conn(struct mg_connection *c) {
-  long len = c->is_tls ? mg_tls_send(c, c->send.buf, c->send.len)
-                       : mg_io_send(c, c->send.buf, c->send.len);
-  if (len > 0) {
-    mg_iobuf_del(&c->send, 0, (size_t) len);
-    mg_call(c, MG_EV_WRITE, &len);
-  }
+#define ETH0 ((struct ETH_Type *) 0x40490000)
+
+#define ETH_PKT_SIZE 1536  // Max frame size
+#define ETH_DESC_CNT 4     // Descriptors count
+#define ETH_DS 2           // Descriptor size (words)
+
+static uint8_t s_rxbuf[ETH_DESC_CNT][ETH_PKT_SIZE];
+static uint8_t s_txbuf[ETH_DESC_CNT][ETH_PKT_SIZE];
+static uint32_t s_rxdesc[ETH_DESC_CNT][ETH_DS];  // RX descriptors
+static uint32_t s_txdesc[ETH_DESC_CNT][ETH_DS];  // TX descriptors
+static uint8_t s_txno;                           // Current TX descriptor
+static uint8_t s_rxno;                           // Current RX descriptor
+
+static struct mg_tcpip_if *s_ifp;  // MIP interface
+enum { MG_PHY_ADDR = 0, MG_PHYREG_BCR = 0, MG_PHYREG_BSR = 1 };
+
+static uint16_t eth_read_phy(uint8_t addr, uint8_t reg) {
+  // WRITE1, READ OPERATION, PHY, REG, WRITE10
+  ETH0->PHY_MANAGEMENT = MG_BIT(30) | MG_BIT(29) | ((addr & 0xf) << 24) |
+                         ((reg & 0x1f) << 18) | MG_BIT(17);
+  while ((ETH0->NETWORK_STATUS & MG_BIT(2)) == 0) (void) 0;
+  return ETH0->PHY_MANAGEMENT & 0xffff;
 }
 
-static void close_conn(struct mg_connection *c) {
-  struct connstate *s = (struct connstate *) (c + 1);
-  mg_iobuf_free(&s->raw);  // For TLS connections, release raw data
-  if (c->is_udp == false && c->is_listening == false) {   // For TCP conns,
-    struct mip_if *ifp = (struct mip_if *) c->mgr->priv;  // send TCP FIN
-    tx_tcp(ifp, c->rem.ip, TH_FIN | TH_ACK, c->loc.port, c->rem.port,
-           mg_htonl(s->seq), mg_htonl(s->ack), NULL, 0);
-  }
-  mg_close_conn(c);
+static void eth_write_phy(uint8_t addr, uint8_t reg, uint16_t val) {
+  ETH0->PHY_MANAGEMENT = MG_BIT(30) | MG_BIT(28) | ((addr & 0xf) << 24) |
+                         ((reg & 0x1f) << 18) | MG_BIT(17) | val;
+  while ((ETH0->NETWORK_STATUS & MG_BIT(2)) == 0) (void) 0;
 }
 
-static bool can_write(struct mg_connection *c) {
-  return c->is_connecting == 0 && c->is_resolving == 0 && c->send.len > 0 &&
-         c->is_tls_hs == 0;
+static uint32_t get_clock_rate(struct mg_tcpip_driver_xmc7_data *d) {
+  // see ETH0 -> NETWORK_CONFIG register
+  (void) d;
+  return 3;
 }
 
-void mg_mgr_poll(struct mg_mgr *mgr, int ms) {
-  struct mg_connection *c, *tmp;
-  uint64_t now = mg_millis();
-  mip_poll((struct mip_if *) mgr->priv, now);
-  mg_timer_poll(&mgr->timers, now);
-  for (c = mgr->conns; c != NULL; c = tmp) {
-    tmp = c->next;
-    mg_call(c, MG_EV_POLL, &now);
-    MG_VERBOSE(("%lu .. %c%c%c%c%c", c->id, c->is_tls ? 'T' : 't',
-                c->is_connecting ? 'C' : 'c', c->is_tls_hs ? 'H' : 'h',
-                c->is_resolving ? 'R' : 'r', c->is_closing ? 'C' : 'c'));
-    if (c->is_tls_hs) mg_tls_handshake(c);
-    if (can_write(c)) write_conn(c);
-    if (c->is_draining && c->send.len == 0) c->is_closing = 1;
-    if (c->is_closing) close_conn(c);
+static bool mg_tcpip_driver_xmc7_init(struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_driver_xmc7_data *d =
+      (struct mg_tcpip_driver_xmc7_data *) ifp->driver_data;
+  s_ifp = ifp;
+
+  // enable controller, set RGMII mode
+  ETH0->CTL = MG_BIT(31) | 2;
+
+  uint32_t cr = get_clock_rate(d);
+  // set NSP change, ignore RX FCS, data bus width, clock rate
+  // frame length 1536, full duplex, speed
+  ETH0->NETWORK_CONFIG = MG_BIT(29) | MG_BIT(26) | MG_BIT(21) |
+                         ((cr & 7) << 18) | MG_BIT(8) | MG_BIT(4) |
+                         MG_BIT(1) | MG_BIT(0);
+
+  // config DMA settings: Force TX burst, Discard on Error, set RX buffer size
+  // to 1536, TX_PBUF_SIZE, RX_PBUF_SIZE, AMBA_BURST_LENGTH
+  ETH0->DMA_CONFIG =
+      MG_BIT(26) | MG_BIT(24) | (0x18 << 16) | MG_BIT(10) | (3 << 8) | 4;
+
+  // initialize descriptors
+  for (int i = 0; i < ETH_DESC_CNT; i++) {
+    s_rxdesc[i][0] = (uint32_t) s_rxbuf[i];
+    if (i == ETH_DESC_CNT - 1) {
+      s_rxdesc[i][0] |= MG_BIT(1);  // mark last descriptor
+    }
+
+    s_txdesc[i][0] = (uint32_t) s_txbuf[i];
+    s_txdesc[i][1] = MG_BIT(31);  // OWN descriptor
+    if (i == ETH_DESC_CNT - 1) {
+      s_txdesc[i][1] |= MG_BIT(30);  // mark last descriptor
+    }
   }
-  (void) ms;
+  ETH0->RECEIVE_Q_PTR = (uint32_t) s_rxdesc;
+  ETH0->TRANSMIT_Q_PTR = (uint32_t) s_txdesc;
+
+  // disable other queues
+  ETH0->TRANSMIT_Q2_PTR = 1;
+  ETH0->TRANSMIT_Q1_PTR = 1;
+  ETH0->RECEIVE_Q2_PTR = 1;
+  ETH0->RECEIVE_Q1_PTR = 1;
+
+  // enable interrupts (TX and RX complete)
+  ETH0->INT_ENABLE = MG_BIT(7) | MG_BIT(1);
+
+  // set MAC address
+  ETH0->SPEC_ADD1_BOTTOM =
+      ifp->mac[3] << 24 | ifp->mac[2] << 16 | ifp->mac[1] << 8 | ifp->mac[0];
+  ETH0->SPEC_ADD1_TOP = ifp->mac[5] << 8 | ifp->mac[4];
+
+  // enable MDIO, TX, RX
+  ETH0->NETWORK_CONTROL = MG_BIT(4) | MG_BIT(3) | MG_BIT(2);
+
+  // start transmission
+  ETH0->NETWORK_CONTROL |= MG_BIT(9);
+
+  // init phy
+  struct mg_phy phy = {eth_read_phy, eth_write_phy};
+  mg_phy_init(&phy, d->phy_addr, MG_PHY_CLOCKS_MAC);
+
+  (void) d;
+  return true;
 }
 
-bool mg_send(struct mg_connection *c, const void *buf, size_t len) {
-  struct mip_if *ifp = (struct mip_if *) c->mgr->priv;
-  bool res = false;
-  if (ifp->ip == 0 || ifp->state != MIP_STATE_READY) {
-    mg_error(c, "net down");
-  } else if (c->is_udp) {
-    tx_udp(ifp, ifp->ip, c->loc.port, c->rem.ip, c->rem.port, buf, len);
-    res = true;
+static size_t mg_tcpip_driver_xmc7_tx(const void *buf, size_t len,
+                                      struct mg_tcpip_if *ifp) {
+  if (len > sizeof(s_txbuf[s_txno])) {
+    MG_ERROR(("Frame too big, %ld", (long) len));
+    len = 0;  // Frame is too big
+  } else if (((s_txdesc[s_txno][1] & MG_BIT(31)) == 0)) {
+    ifp->nerr++;
+    MG_ERROR(("No free descriptors"));
+    len = 0;  // All descriptors are busy, fail
   } else {
-    res = mg_iobuf_add(&c->send, c->send.len, buf, len);
-  }
-  return res;
-}
+    memcpy(s_txbuf[s_txno], buf, len);
+    s_txdesc[s_txno][1] = (s_txno == ETH_DESC_CNT - 1 ? MG_BIT(30) : 0) |
+                          MG_BIT(15) | len;  // Last buffer and length
 
-#ifdef MIP_QPROFILE
+    ETH0->NETWORK_CONTROL |= MG_BIT(9);  // enable transmission
+    if (++s_txno >= ETH_DESC_CNT) s_txno = 0;
+  }
 
-#pragma pack(push, 1)
-struct qpentry {
-  uint32_t timestamp;
-  uint16_t type;
-  uint16_t len;
-};
-#pragma pack(pop)
+  MG_DSB();
+  ETH0->TRANSMIT_STATUS = ETH0->TRANSMIT_STATUS;
+  ETH0->NETWORK_CONTROL |= MG_BIT(9);  // enable transmission
 
-static struct queue qp;
+  return len;
+}
 
-// This is called from IRQ and main contexts; two producers, single consumer
-// TODO(scaprile): avoid concurrency issues (2 queues ?)
-void qp_mark(unsigned int type, int len) {
-  static bool ovf = false;
-  static uint16_t irq_ctr = 0, drop_ctr = 0;
-  struct qpentry e = {.timestamp = (uint32_t) mg_millis(),
-                      .type = (uint16_t) type,
-                      .len = (uint16_t) len};
-  if (type == QP_IRQTRIGGERED) e.len = ++irq_ctr;
-  if (ovf) {
-    e.type = (uint16_t) QP_QUEUEOVF;
-    e.len = drop_ctr;
+static bool mg_tcpip_driver_xmc7_up(struct mg_tcpip_if *ifp) {
+  struct mg_tcpip_driver_xmc7_data *d =
+      (struct mg_tcpip_driver_xmc7_data *) ifp->driver_data;
+  uint8_t speed = MG_PHY_SPEED_10M;
+  bool up = false, full_duplex = false;
+  struct mg_phy phy = {eth_read_phy, eth_write_phy};
+  up = mg_phy_up(&phy, d->phy_addr, &full_duplex, &speed);
+  if ((ifp->state == MG_TCPIP_STATE_DOWN) && up) {  // link state just went up
+    if (speed == MG_PHY_SPEED_1000M) {
+		  ETH0->NETWORK_CONFIG |= MG_BIT(10);
+	  }
+    MG_DEBUG(("Link is %uM %s-duplex",
+              speed == MG_PHY_SPEED_10M ? 10 : 
+              (speed == MG_PHY_SPEED_100M ? 100 : 1000),
+              full_duplex ? "full" : "half"));
   }
-  ovf = !q_write(&qp, &e, sizeof(e));
+  (void) d;
+  return up;
 }
 
-void qp_log(void) {
-  struct qpentry e;
-  const char *titles[] = {"IRQ ", "PUSH", "POP ", "DONE", "DROP", "OVFL"};
-  for (int i = 0; i < 10 && q_read(&qp, &e); i++) {
-    MG_INFO(("%lx %s %u", e.timestamp, titles[e.type], e.len));
+void ETH_IRQHandler(void) {
+  uint32_t irq_status = ETH0->INT_STATUS;
+  if (irq_status & MG_BIT(1)) {
+    for (uint8_t i = 0; i < ETH_DESC_CNT; i++) {
+      if (s_rxdesc[s_rxno][0] & MG_BIT(0)) {
+        size_t len = s_rxdesc[s_rxno][1] & (MG_BIT(13) - 1);
+        //MG_INFO(("Receive complete: %ld bytes", len));
+        mg_tcpip_qwrite(s_rxbuf[s_rxno], len, s_ifp);
+        s_rxdesc[s_rxno][0] &= ~MG_BIT(0);  // OWN bit: handle control to DMA
+        if (++s_rxno >= ETH_DESC_CNT) s_rxno = 0;
+      }
+    }
   }
-}
 
-void qp_init(void) {
-  qp.len = 500 * (sizeof(size_t) + sizeof(struct qpentry));
-  qp.buf = calloc(1, qp.len);  // THERE IS NO FREE
+  ETH0->INT_STATUS = irq_status;
 }
-#endif  // MIP_QPROFILE
 
-#endif  // MG_ENABLE_MIP
+struct mg_tcpip_driver mg_tcpip_driver_xmc7 = {mg_tcpip_driver_xmc7_init,
+                                               mg_tcpip_driver_xmc7_tx, NULL,
+                                               mg_tcpip_driver_xmc7_up};
+#endif
diff --git a/mongoose/mongoose.h b/mongoose/mongoose.h
index 350aad9c..3a439a6e 100644
--- a/mongoose/mongoose.h
+++ b/mongoose/mongoose.h
@@ -1,5 +1,5 @@
 // Copyright (c) 2004-2013 Sergey Lyubka
-// Copyright (c) 2013-2022 Cesanta Software Limited
+// Copyright (c) 2013-2024 Cesanta Software Limited
 // All rights reserved
 //
 // This software is dual-licensed: you can redistribute it and/or modify
@@ -15,58 +15,48 @@
 // Alternatively, you can license this software under a commercial
 // license, as set out in https://www.mongoose.ws/licensing/
 //
-// SPDX-License-Identifier: GPL-2.0-only
+// SPDX-License-Identifier: GPL-2.0-only or commercial
 
 #ifndef MONGOOSE_H
 #define MONGOOSE_H
 
-#define MG_VERSION "7.8"
+#define MG_VERSION "7.14"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 
-#define MG_ARCH_CUSTOM 0     // User creates its own mongoose_custom.h
-#define MG_ARCH_UNIX 1       // Linux, BSD, Mac, ...
-#define MG_ARCH_WIN32 2      // Windows
-#define MG_ARCH_ESP32 3      // ESP32
-#define MG_ARCH_ESP8266 4    // ESP8266
-#define MG_ARCH_FREERTOS 5   // FreeRTOS
-#define MG_ARCH_AZURERTOS 6  // MS Azure RTOS
-#define MG_ARCH_ZEPHYR 7     // Zephyr RTOS
-#define MG_ARCH_NEWLIB 8     // Bare metal ARM
-#define MG_ARCH_RTX 9        // Keil MDK RTX
-#define MG_ARCH_TIRTOS 10    // Texas Semi TI-RTOS
-#define MG_ARCH_RP2040 11    // Raspberry Pi RP2040
+#define MG_ARCH_CUSTOM 0        // User creates its own mongoose_config.h
+#define MG_ARCH_UNIX 1          // Linux, BSD, Mac, ...
+#define MG_ARCH_WIN32 2         // Windows
+#define MG_ARCH_ESP32 3         // ESP32
+#define MG_ARCH_ESP8266 4       // ESP8266
+#define MG_ARCH_FREERTOS 5      // FreeRTOS
+#define MG_ARCH_AZURERTOS 6     // MS Azure RTOS
+#define MG_ARCH_ZEPHYR 7        // Zephyr RTOS
+#define MG_ARCH_NEWLIB 8        // Bare metal ARM
+#define MG_ARCH_CMSIS_RTOS1 9   // CMSIS-RTOS API v1 (Keil RTX)
+#define MG_ARCH_TIRTOS 10       // Texas Semi TI-RTOS
+#define MG_ARCH_RP2040 11       // Raspberry Pi RP2040
+#define MG_ARCH_ARMCC 12        // Keil MDK-Core with Configuration Wizard
+#define MG_ARCH_CMSIS_RTOS2 13  // CMSIS-RTOS API v2 (Keil RTX5, FreeRTOS)
+#define MG_ARCH_RTTHREAD 14     // RT-Thread RTOS
 
 #if !defined(MG_ARCH)
 #if defined(__unix__) || defined(__APPLE__)
 #define MG_ARCH MG_ARCH_UNIX
 #elif defined(_WIN32)
 #define MG_ARCH MG_ARCH_WIN32
-#elif defined(ICACHE_FLASH) || defined(ICACHE_RAM_ATTR)
-#define MG_ARCH MG_ARCH_ESP8266
-#elif defined(__ZEPHYR__)
-#define MG_ARCH MG_ARCH_ZEPHYR
-#elif defined(ESP_PLATFORM)
-#define MG_ARCH MG_ARCH_ESP32
-#elif defined(FREERTOS_IP_H)
-#define MG_ARCH MG_ARCH_FREERTOS
-#define MG_ENABLE_FREERTOS_TCP 1
-#elif defined(AZURE_RTOS_THREADX)
-#define MG_ARCH MG_ARCH_AZURERTOS
-#elif defined(PICO_TARGET_NAME)
-#define MG_ARCH MG_ARCH_RP2040
 #endif
 #endif  // !defined(MG_ARCH)
 
 #if !defined(MG_ARCH) || (MG_ARCH == MG_ARCH_CUSTOM)
-#include "mongoose_custom.h"  // keep this include
+#include "mongoose_config.h"  // keep this include
 #endif
 
 #if !defined(MG_ARCH)
-#error "MG_ARCH is not specified and we couldn't guess it. Set -D MG_ARCH=..."
+#error "MG_ARCH is not specified and we couldn't guess it. Define MG_ARCH=... in your compiler"
 #endif
 
 // http://esr.ibiblio.org/?p=5095
@@ -130,7 +120,8 @@ extern "C" {
 #include <sys/types.h>
 #include <time.h>
 
-#include <esp_timer.h>
+#include <esp_ota_ops.h>  // Use angle brackets to avoid
+#include <esp_timer.h>    // amalgamation ditching them
 
 #define MG_PATH_MAX 128
 
@@ -166,15 +157,24 @@ extern "C" {
 #if MG_ARCH == MG_ARCH_FREERTOS
 
 #include <ctype.h>
-// #include <errno.h> // Cannot include errno - might conflict with lwip!
+#if !defined(MG_ENABLE_LWIP) || !MG_ENABLE_LWIP
+#include <errno.h>
+#endif
 #include <stdarg.h>
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
-#include <stdlib.h> // rand(), strtol(), atoi()
+#include <stdlib.h>  // rand(), strtol(), atoi()
 #include <string.h>
+#if defined(__ARMCC_VERSION)
+#define mode_t size_t
+#include <alloca.h>
+#include <time.h>
+#elif defined(__CCRH__)
+#else
 #include <sys/stat.h>
+#endif
 
 #include <FreeRTOS.h>
 #include <task.h>
@@ -186,7 +186,7 @@ extern "C" {
 #define calloc(a, b) mg_calloc(a, b)
 #define free(a) vPortFree(a)
 #define malloc(a) pvPortMalloc(a)
-#define strdup(s) ((char *) mg_strdup(mg_str(s)).ptr)
+#define strdup(s) mg_mprintf("%s", s)
 
 // Re-route calloc/free to the FreeRTOS's functions, don't use stdlib
 static inline void *mg_calloc(size_t cnt, size_t size) {
@@ -240,9 +240,34 @@ static inline int mg_mkdir(const char *path, mode_t mode) {
 #include <pico/stdlib.h>
 int mkdir(const char *, mode_t);
 #endif
-
-
-#if MG_ARCH == MG_ARCH_RTX
+

+

+#if MG_ARCH == MG_ARCH_RTTHREAD

+

+#include <rtthread.h>

+#include <ctype.h>

+#include <errno.h>

+#include <fcntl.h>

+#include <sys/socket.h>

+#include <sys/select.h>

+#include <stdarg.h>

+#include <stdbool.h>

+#include <stdint.h>

+#include <stdio.h>

+#include <stdlib.h>

+#include <string.h>
