diff mbox series

[libnftnl,2/4] utils: Add helpers for interface name wildcards

Message ID 20241002191941.8410-3-phil@nwl.cc
State New
Headers show
Series Support wildcard netdev hooks and events | expand

Commit Message

Phil Sutter Oct. 2, 2024, 7:19 p.m. UTC 
Support simple (suffix) wildcards in NFTNL_CHAIN_DEV(ICES) and
NFTA_FLOWTABLE_HOOK_DEVS identified by non-NUL-terminated strings. Add
helpers converting to and from the human-readable asterisk-suffix
notation.

Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 include/utils.h |  4 ++++
 src/chain.c     | 16 ++++++++++------
 src/flowtable.c | 10 ++++++----
 src/utils.c     | 30 ++++++++++++++++++++++++++++++
 4 files changed, 50 insertions(+), 10 deletions(-)
diff mbox series

Patch

diff --git a/include/utils.h b/include/utils.h
index 247d99d19dd7f..c8e890eae2ffd 100644
--- a/include/utils.h
+++ b/include/utils.h
@@ -6,6 +6,7 @@ 
 #include <stdint.h>
 #include <string.h>
 #include <stdlib.h>
+#include <libmnl/libmnl.h>
 #include <libnftnl/common.h>
 
 #include "config.h"
@@ -83,4 +84,7 @@  int nftnl_fprintf(FILE *fpconst, const void *obj, uint32_t cmd, uint32_t type,
 int nftnl_set_str_attr(const char **dptr, uint32_t *flags,
 		       uint16_t attr, const void *data, uint32_t data_len);
 
+void mnl_attr_put_ifname(struct nlmsghdr *nlh, int attr, const char *ifname);
+const char *mnl_attr_get_ifname(struct nlattr *attr);
+
 #endif
diff --git a/src/chain.c b/src/chain.c
index 0b68939fe21a7..830e09fcfbbb1 100644
--- a/src/chain.c
+++ b/src/chain.c
@@ -490,14 +490,14 @@  void nftnl_chain_nlmsg_build_payload(struct nlmsghdr *nlh, const struct nftnl_ch
 		mnl_attr_put_u32(nlh, NFTA_HOOK_PRIORITY, htonl(c->prio));
 
 	if (c->flags & (1 << NFTNL_CHAIN_DEV))
-		mnl_attr_put_strz(nlh, NFTA_HOOK_DEV, c->dev);
+		mnl_attr_put_ifname(nlh, NFTA_HOOK_DEV, c->dev);
 	else if (c->flags & (1 << NFTNL_CHAIN_DEVICES)) {
 		struct nlattr *nest_dev;
 
 		nest_dev = mnl_attr_nest_start(nlh, NFTA_HOOK_DEVS);
 		for (i = 0; i < c->dev_array_len; i++)
-			mnl_attr_put_strz(nlh, NFTA_DEVICE_NAME,
-					  c->dev_array[i]);
+			mnl_attr_put_ifname(nlh, NFTA_DEVICE_NAME,
+					    c->dev_array[i]);
 		mnl_attr_nest_end(nlh, nest_dev);
 	}
 
@@ -677,8 +677,10 @@  static int nftnl_chain_parse_devs(struct nlattr *nest, struct nftnl_chain *c)
 	mnl_attr_for_each_nested(attr, nest) {
 		if (mnl_attr_get_type(attr) != NFTA_DEVICE_NAME)
 			goto err;
-		dev_array[len++] = strdup(mnl_attr_get_str(attr));
-		if (len >= size) {
+		dev_array[len] = strdup(mnl_attr_get_ifname(attr));
+		if (!dev_array[len])
+			goto err;
+		if (++len >= size) {
 			tmp = realloc(dev_array, size * 2 * sizeof(char *));
 			if (!tmp)
 				goto err;
@@ -717,7 +719,9 @@  static int nftnl_chain_parse_hook(struct nlattr *attr, struct nftnl_chain *c)
 		c->flags |= (1 << NFTNL_CHAIN_PRIO);
 	}
 	if (tb[NFTA_HOOK_DEV]) {
-		c->dev = strdup(mnl_attr_get_str(tb[NFTA_HOOK_DEV]));
+		if (c->flags & (1 << NFTNL_CHAIN_DEV))
+			xfree(c->dev);
+		c->dev = strdup(mnl_attr_get_ifname(tb[NFTA_HOOK_DEV]));
 		if (!c->dev)
 			return -1;
 		c->flags |= (1 << NFTNL_CHAIN_DEV);
diff --git a/src/flowtable.c b/src/flowtable.c
index 41a1456bb19b2..74cffc812996c 100644
--- a/src/flowtable.c
+++ b/src/flowtable.c
@@ -328,8 +328,8 @@  void nftnl_flowtable_nlmsg_build_payload(struct nlmsghdr *nlh,
 
 		nest_dev = mnl_attr_nest_start(nlh, NFTA_FLOWTABLE_HOOK_DEVS);
 		for (i = 0; i < c->dev_array_len; i++) {
-			mnl_attr_put_strz(nlh, NFTA_DEVICE_NAME,
-					  c->dev_array[i]);
+			mnl_attr_put_ifname(nlh, NFTA_DEVICE_NAME,
+					    c->dev_array[i]);
 		}
 		mnl_attr_nest_end(nlh, nest_dev);
 	}
@@ -416,8 +416,10 @@  static int nftnl_flowtable_parse_devs(struct nlattr *nest,
 	mnl_attr_for_each_nested(attr, nest) {
 		if (mnl_attr_get_type(attr) != NFTA_DEVICE_NAME)
 			goto err;
-		dev_array[len++] = strdup(mnl_attr_get_str(attr));
-		if (len >= size) {
+		dev_array[len] = strdup(mnl_attr_get_ifname(attr));
+		if (!dev_array[len])
+			goto err;
+		if (++len >= size) {
 			tmp = realloc(dev_array, size * 2 * sizeof(char *));
 			if (!tmp)
 				goto err;
diff --git a/src/utils.c b/src/utils.c
index 2f1ffd6227583..df00ce04b32ea 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -17,8 +17,11 @@ 
 #include <errno.h>
 #include <inttypes.h>
 
+#include <libmnl/libmnl.h>
+
 #include <libnftnl/common.h>
 
+#include <linux/if.h>
 #include <linux/netfilter.h>
 #include <linux/netfilter/nf_tables.h>
 
@@ -150,3 +153,30 @@  int nftnl_set_str_attr(const char **dptr, uint32_t *flags,
 	*flags |= (1 << attr);
 	return 0;
 }
+
+void mnl_attr_put_ifname(struct nlmsghdr *nlh, int attr, const char *ifname)
+{
+	int len = strlen(ifname) + 1;
+
+	if (ifname[len - 2] == '*')
+		len -= 2;
+
+	mnl_attr_put(nlh, attr, len, ifname);
+}
+
+const char *mnl_attr_get_ifname(struct nlattr *attr)
+{
+	size_t slen = mnl_attr_get_payload_len(attr);
+	const char *dev = mnl_attr_get_str(attr);
+	static char buf[IFNAMSIZ];
+
+	if (dev[slen - 1] == '\0')
+		return dev;
+
+	if (slen > IFNAMSIZ - 2)
+		slen = IFNAMSIZ - 2;
+
+	memcpy(buf, dev, slen);
+	memcpy(buf + slen, "*\0", 2);
+	return buf;
+}