diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index bd91a4b..1ff0135 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -15,10 +15,12 @@
 #include "qemu/iov.h"
 #include "hw/virtio/virtio.h"
 #include "net/net.h"
+#include "net/eth.h"
 #include "net/checksum.h"
 #include "net/tap.h"
 #include "qemu/error-report.h"
 #include "qemu/timer.h"
+#include "qemu/sockets.h"
 #include "hw/virtio/virtio-net.h"
 #include "net/vhost_net.h"
 #include "hw/virtio/virtio-bus.h"
@@ -38,6 +40,25 @@
 #define endof(container, field) \
     (offsetof(container, field) + sizeof(((container *)0)->field))
 
+#define VIRTIO_NET_IP4_ADDR_SIZE   8        /* ipv4 saddr + daddr */
+#define VIRTIO_NET_TCP_PORT_SIZE   4        /* sport + dport */
+
+#define VIRTIO_NET_TCP_FLAG         0x3F
+#define VIRTIO_NET_TCP_HDR_LENGTH   0xF000
+
+/* IPv4 max payload, 16 bits in the header */
+#define VIRTIO_NET_MAX_IP4_PAYLOAD (65535 - sizeof(struct ip_header))
+#define VIRTIO_NET_MAX_TCP_PAYLOAD 65535
+
+/* header length value in ip header without option */
+#define VIRTIO_NET_IP4_HEADER_LENGTH 5
+
+/* Purge coalesced packets timer interval, This value affects the performance
+   a lot, and should be tuned carefully, '300000'(300us) is the recommended
+   value to pass the WHQL test, '50000' can gain 2x netperf throughput with
+   tso/gso/gro 'off'. */
+#define VIRTIO_NET_RSC_INTERVAL  300000
+
 typedef struct VirtIOFeature {
     uint32_t flags;
     size_t end;
@@ -1688,20 +1709,476 @@ static int virtio_net_load_device(VirtIODevice *vdev, QEMUFile *f,
     return 0;
 }
 
+static void virtio_net_rsc_extract_unit4(NetRscChain *chain,
+                                         const uint8_t *buf, NetRscUnit* unit)
+{
+    uint16_t hdr_len;
+    uint16_t ip_hdrlen;
+    struct ip_header *ip;
+
+    hdr_len = chain->n->guest_hdr_len;
+    ip = (struct ip_header *)(buf + hdr_len + sizeof(struct eth_header));
+    unit->ip = (void *)ip;
+    ip_hdrlen = (ip->ip_ver_len & 0xF) << 2;
+    unit->ip_plen = &ip->ip_len;
+    unit->tcp = (struct tcp_header *)(((uint8_t *)unit->ip) + ip_hdrlen);
+    unit->tcp_hdrlen = (htons(unit->tcp->th_offset_flags) & 0xF000) >> 10;
+    unit->payload = htons(*unit->ip_plen) - ip_hdrlen - unit->tcp_hdrlen;
+}
+
+static void virtio_net_rsc_ipv4_checksum(struct virtio_net_hdr* vhdr,
+                                         struct ip_header *ip)
+{
+    uint32_t sum;
+
+    ip->ip_sum = 0;
+    sum = net_checksum_add_cont(sizeof(struct ip_header), (uint8_t *)ip, 0);
+    ip->ip_sum = cpu_to_be16(net_checksum_finish(sum));
+    vhdr->flags &= ~VIRTIO_NET_HDR_F_NEEDS_CSUM;
+    vhdr->flags |= VIRTIO_NET_HDR_F_DATA_VALID;
+}
+
+static size_t virtio_net_rsc_drain_seg(NetRscChain *chain, NetRscSeg *seg)
+{
+    int ret;
+    struct virtio_net_hdr *h;
+
+    h = (struct virtio_net_hdr *)seg->buf; 
+    virtio_net_rsc_ipv4_checksum(h, seg->unit.ip);
+    h->coalesced = seg->packets; 
+    h->dup_ack = seg->dup_ack_count; 
+    h->gso_type = chain->gso_type;
+    h->gso_size = chain->max_payload; 
+    ret = virtio_net_do_receive(seg->nc, seg->buf, seg->size);
+    QTAILQ_REMOVE(&chain->buffers, seg, next);
+    g_free(seg->buf);
+    g_free(seg);
+
+    return ret;
+}
+
+static void virtio_net_rsc_purge(void *opq)
+{
+    NetRscSeg *seg, *rn;
+    NetRscChain *chain = (NetRscChain *)opq;
+
+    QTAILQ_FOREACH_SAFE(seg, &chain->buffers, next, rn) {
+        if (virtio_net_rsc_drain_seg(chain, seg) == 0) {
+            chain->stat.purge_failed++;
+            continue;
+        }
+    }
+
+    chain->stat.timer++;
+    if (!QTAILQ_EMPTY(&chain->buffers)) {
+        timer_mod(chain->drain_timer,
+              qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + chain->n->rsc_timeout);
+    }
+}
+
+static void virtio_net_rsc_cleanup(VirtIONet *n)
+{
+    NetRscChain *chain, *rn_chain;
+    NetRscSeg *seg, *rn_seg;
+
+    QTAILQ_FOREACH_SAFE(chain, &n->rsc_chains, next, rn_chain) {
+        QTAILQ_FOREACH_SAFE(seg, &chain->buffers, next, rn_seg) {
+            QTAILQ_REMOVE(&chain->buffers, seg, next);
+            g_free(seg->buf);
+            g_free(seg);
+        }
+
+        timer_del(chain->drain_timer);
+        timer_free(chain->drain_timer);
+        QTAILQ_REMOVE(&n->rsc_chains, chain, next);
+        g_free(chain);
+    }
+}
+
+static void virtio_net_rsc_cache_buf(NetRscChain *chain, NetClientState *nc,
+                                     const uint8_t *buf, size_t size)
+{
+    uint16_t hdr_len;
+    NetRscSeg *seg;
+
+    hdr_len = chain->n->guest_hdr_len;
+    seg = g_malloc(sizeof(NetRscSeg));
+    seg->buf = g_malloc(hdr_len + sizeof(struct eth_header)\
+                   + VIRTIO_NET_MAX_TCP_PAYLOAD);
+    memcpy(seg->buf, buf, size);
+    seg->size = size;
+    seg->packets = 1;
+    seg->dup_ack_count = 0;
+    seg->is_coalesced = 0;
+    seg->nc = nc;
+
+    QTAILQ_INSERT_TAIL(&chain->buffers, seg, next);
+    chain->stat.cache++;
+
+    virtio_net_rsc_extract_unit4(chain, seg->buf, &seg->unit);
+}
+
+static int32_t virtio_net_rsc_handle_ack(NetRscChain *chain,
+                                         NetRscSeg *seg, const uint8_t *buf,
+                                         struct tcp_header *n_tcp,
+                                         struct tcp_header *o_tcp)
+{
+    uint32_t nack, oack;
+    uint16_t nwin, owin;
+
+    nack = htonl(n_tcp->th_ack);
+    nwin = htons(n_tcp->th_win);
+    oack = htonl(o_tcp->th_ack);
+    owin = htons(o_tcp->th_win);
+
+    if ((nack - oack) >= VIRTIO_NET_MAX_TCP_PAYLOAD) {
+        chain->stat.ack_out_of_win++;
+        return RSC_FINAL;
+    } else if (nack == oack) {
+        /* duplicated ack or window probe */
+        if (nwin == owin) {
+            /* duplicated ack, add dup ack count due to whql test up to 1 */
+            chain->stat.dup_ack++;
+            return RSC_FINAL;
+        } else {
+            /* Coalesce window update */
+            o_tcp->th_win = n_tcp->th_win;
+            chain->stat.win_update++;
+            return RSC_COALESCE;
+        }
+    } else {
+        /* pure ack, go to 'C', finalize*/
+        chain->stat.pure_ack++;
+        return RSC_FINAL;
+    }
+}
+
+static int32_t virtio_net_rsc_coalesce_data(NetRscChain *chain,
+                                            NetRscSeg *seg, const uint8_t *buf,
+                                            NetRscUnit *n_unit)
+{
+    void *data;
+    uint16_t o_ip_len;
+    uint32_t nseq, oseq;
+    NetRscUnit *o_unit;
+
+    o_unit = &seg->unit;
+    o_ip_len = htons(*o_unit->ip_plen);
+    nseq = htonl(n_unit->tcp->th_seq);
+    oseq = htonl(o_unit->tcp->th_seq);
+
+    /* out of order or retransmitted. */
+    if ((nseq - oseq) > VIRTIO_NET_MAX_TCP_PAYLOAD) {
+        chain->stat.data_out_of_win++;
+        return RSC_FINAL;
+    }
+
+    data = ((uint8_t *)n_unit->tcp) + n_unit->tcp_hdrlen;
+    if (nseq == oseq) {
+        if ((o_unit->payload == 0) && n_unit->payload) {
+            /* From no payload to payload, normal case, not a dup ack or etc */
+            chain->stat.data_after_pure_ack++;
+            goto coalesce;
+        } else {
+            return virtio_net_rsc_handle_ack(chain, seg, buf,
+                                             n_unit->tcp, o_unit->tcp);
+        }
+    } else if ((nseq - oseq) != o_unit->payload) {
+        /* Not a consistent packet, out of order */
+        chain->stat.data_out_of_order++;
+        return RSC_FINAL;
+    } else {
+coalesce:
+        if ((o_ip_len + n_unit->payload) > chain->max_payload) {
+            chain->stat.over_size++;
+            return RSC_FINAL;
+        }
+
+        /* Here comes the right data, the payload length in v4/v6 is different,
+           so use the field value to update and record the new data len */
+        o_unit->payload += n_unit->payload; /* update new data len */
+
+        /* update field in ip header */
+        *o_unit->ip_plen = htons(o_ip_len + n_unit->payload);
+
+        /* Bring 'PUSH' big, the whql test guide says 'PUSH' can be coalesced
+           for windows guest, while this may change the behavior for linux
+           guest. */
+        o_unit->tcp->th_offset_flags = n_unit->tcp->th_offset_flags;
+
+        o_unit->tcp->th_ack = n_unit->tcp->th_ack;
+        o_unit->tcp->th_win = n_unit->tcp->th_win;
+
+        memmove(seg->buf + seg->size, data, n_unit->payload);
+        seg->size += n_unit->payload;
+        seg->packets++;
+        chain->stat.coalesced++;
+        return RSC_COALESCE;
+    }
+}
+
+static int32_t virtio_net_rsc_coalesce4(NetRscChain *chain, NetRscSeg *seg,
+                                        const uint8_t *buf, size_t size,
+                                        NetRscUnit *unit)
+{
+    struct ip_header *ip1, *ip2;
+
+    ip1 = (struct ip_header *)(unit->ip);
+    ip2 = (struct ip_header *)(seg->unit.ip);
+    if ((ip1->ip_src ^ ip2->ip_src) || (ip1->ip_dst ^ ip2->ip_dst)
+        || (unit->tcp->th_sport ^ seg->unit.tcp->th_sport)
+        || (unit->tcp->th_dport ^ seg->unit.tcp->th_dport)) {
+        chain->stat.no_match++;
+        return RSC_NO_MATCH;
+    }
+
+    return virtio_net_rsc_coalesce_data(chain, seg, buf, unit);
+}
+
+/* Pakcets with 'SYN' should bypass, other flag should be sent after drain
+ * to prevent out of order */
+static int virtio_net_rsc_tcp_ctrl_check(NetRscChain *chain,
+                                         struct tcp_header *tcp)
+{
+    uint16_t tcp_hdr;
+    uint16_t tcp_flag;
+
+    tcp_flag = htons(tcp->th_offset_flags);
+    tcp_hdr = (tcp_flag & VIRTIO_NET_TCP_HDR_LENGTH) >> 10;
+    tcp_flag &= VIRTIO_NET_TCP_FLAG;
+    tcp_flag = htons(tcp->th_offset_flags) & 0x3F;
+    if (tcp_flag & TH_SYN) {
+        chain->stat.tcp_syn++;
+        return RSC_BYPASS;
+    }
+
+    if (tcp_flag & (TH_FIN | TH_URG | TH_RST)) {
+        chain->stat.tcp_ctrl_drain++;
+        return RSC_FINAL;
+    }
+
+    if (tcp_hdr > sizeof(struct tcp_header)) {
+        chain->stat.tcp_all_opt++; 
+        return RSC_FINAL;
+    }
+
+    return RSC_WANT;
+}
+
+static bool virtio_net_rsc_empty_cache(NetRscChain *chain, NetClientState *nc,
+                                       const uint8_t *buf, size_t size)
+{
+    if (QTAILQ_EMPTY(&chain->buffers)) {
+        chain->stat.empty_cache++;
+        virtio_net_rsc_cache_buf(chain, nc, buf, size);
+        timer_mod(chain->drain_timer,
+              qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + chain->n->rsc_timeout);
+        return 1;
+    }
+
+    return 0;
+}
+
+static size_t virtio_net_rsc_do_coalesce(NetRscChain *chain, NetClientState *nc,
+                                         const uint8_t *buf, size_t size,
+                                         NetRscUnit *unit)
+{
+    int ret;
+    NetRscSeg *seg, *nseg;
+
+    QTAILQ_FOREACH_SAFE(seg, &chain->buffers, next, nseg) {
+        ret = virtio_net_rsc_coalesce4(chain, seg, buf, size, unit);
+
+        if (ret == RSC_FINAL) {
+            if (virtio_net_rsc_drain_seg(chain, seg) == 0) {
+                /* Send failed */
+                chain->stat.final_failed++;
+                return 0;
+            }
+
+            /* Send current packet */
+            return virtio_net_do_receive(nc, buf, size);
+        } else if (ret == RSC_NO_MATCH) {
+            continue;
+        } else {
+            /* Coalesced, mark coalesced flag to tell calc cksum for ipv4 */
+            seg->is_coalesced = 1;
+            return size;
+        }
+    }
+
+    chain->stat.no_match_cache++;
+    virtio_net_rsc_cache_buf(chain, nc, buf, size);
+    return size;
+}
+
+/* Drain a connection data, this is to avoid out of order segments */
+static size_t virtio_net_rsc_drain_flow(NetRscChain *chain, NetClientState *nc,
+                                        const uint8_t *buf, size_t size,
+                                        uint16_t ip_start, uint16_t ip_size,
+                                        uint16_t tcp_port, uint16_t port_size)
+{
+    NetRscSeg *seg, *nseg;
+
+    QTAILQ_FOREACH_SAFE(seg, &chain->buffers, next, nseg) {
+        if (memcmp(buf + ip_start, seg->buf + ip_start, ip_size)
+            || memcmp(buf + tcp_port, seg->buf + tcp_port, port_size)) {
+            continue;
+        }
+        if (virtio_net_rsc_drain_seg(chain, seg) == 0) {
+            chain->stat.drain_failed++;
+        }
+
+        break;
+    }
+
+    return virtio_net_do_receive(nc, buf, size);
+}
+
+static int32_t virtio_net_rsc_sanity_check4(NetRscChain *chain,
+                                            struct ip_header *ip,
+                                            const uint8_t *buf, size_t size)
+{
+    uint16_t ip_len;
+    uint16_t hdr_len;
+
+    hdr_len = chain->n->guest_hdr_len;
+    if (size < (hdr_len + sizeof(struct eth_header) + sizeof(struct ip_header)
+        + sizeof(struct tcp_header))) {
+        return RSC_BYPASS;
+    }
+
+    /* Not an ipv4 one */
+    if (((ip->ip_ver_len & 0xF0) >> 4) != IP_HEADER_VERSION_4) {
+        chain->stat.ip_option++;
+        return RSC_BYPASS;
+    }
+
+    /* Don't handle packets with ip option */
+    if (VIRTIO_NET_IP4_HEADER_LENGTH != (ip->ip_ver_len & 0xF)) {
+        chain->stat.ip_option++;
+        return RSC_BYPASS;
+    }
+
+    if (ip->ip_p != IPPROTO_TCP) {
+        chain->stat.bypass_not_tcp++;
+        return RSC_BYPASS;
+    }
+
+    /* Don't handle packets with ip fragment */
+    if (!(htons(ip->ip_off) & IP_DF)) {
+        chain->stat.ip_frag++;
+        return RSC_BYPASS;
+    }
+
+    ip_len = htons(ip->ip_len);
+    if (ip_len < (sizeof(struct ip_header) + sizeof(struct tcp_header))
+        || ip_len > (size - hdr_len - sizeof(struct eth_header))) {
+        chain->stat.ip_hacked++;
+        return RSC_BYPASS;
+    }
+
+    return RSC_WANT;
+}
+
+static size_t virtio_net_rsc_receive4(NetRscChain *chain, NetClientState* nc,
+                                      const uint8_t *buf, size_t size)
+{
+    int32_t ret;
+    uint16_t hdr_len;
+    NetRscUnit unit;
+
+    hdr_len = ((VirtIONet *)(chain->n))->guest_hdr_len;
+    virtio_net_rsc_extract_unit4(chain, buf, &unit);
+    if (RSC_WANT != virtio_net_rsc_sanity_check4(chain, unit.ip, buf, size)) {
+        return virtio_net_do_receive(nc, buf, size);
+    }
+
+    ret = virtio_net_rsc_tcp_ctrl_check(chain, unit.tcp);
+    if (ret == RSC_BYPASS) {
+        return virtio_net_do_receive(nc, buf, size);
+    } else if (ret == RSC_FINAL) {
+        return virtio_net_rsc_drain_flow(chain, nc, buf, size,
+                ((hdr_len + sizeof(struct eth_header)) + 12),
+                VIRTIO_NET_IP4_ADDR_SIZE,
+                hdr_len + sizeof(struct eth_header) + sizeof(struct ip_header),
+                VIRTIO_NET_TCP_PORT_SIZE);
+    }
+
+    if (virtio_net_rsc_empty_cache(chain, nc, buf, size)) {
+        return size;
+    }
+
+    return virtio_net_rsc_do_coalesce(chain, nc, buf, size, &unit);
+}
+
+static NetRscChain *virtio_net_rsc_lookup_chain(VirtIONet * n,
+                                                NetClientState *nc,
+                                                uint16_t proto)
+{
+    NetRscChain *chain;
+
+    if (proto != (uint16_t)ETH_P_IP) {
+        return NULL;
+    }
+
+    QTAILQ_FOREACH(chain, &n->rsc_chains, next) {
+        if (chain->proto == proto) {
+            return chain;
+        }
+    }
+
+    chain = g_malloc(sizeof(*chain));
+    chain->n = n;
+    chain->proto = proto;
+    chain->max_payload = VIRTIO_NET_MAX_IP4_PAYLOAD;
+    chain->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
+    chain->drain_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
+                                      virtio_net_rsc_purge, chain);
+    memset(&chain->stat, 0, sizeof(chain->stat));
+
+    QTAILQ_INIT(&chain->buffers);
+    QTAILQ_INSERT_TAIL(&n->rsc_chains, chain, next);
+
+    return chain;
+}
 
 static ssize_t virtio_net_rsc_receive(NetClientState *nc,
                                       const uint8_t *buf, size_t size)
 {
-    return virtio_net_do_receive(nc, buf, size);
+    uint16_t proto;
+    NetRscChain *chain;
+    struct eth_header *eth;
+    VirtIONet *n;
+
+    n = qemu_get_nic_opaque(nc);
+    if (size < (n->guest_hdr_len + sizeof(struct eth_header))) {
+        return virtio_net_do_receive(nc, buf, size);
+    }
+
+    eth = (struct eth_header *)(buf + n->guest_hdr_len);
+    proto = htons(eth->h_proto);
+
+    chain = virtio_net_rsc_lookup_chain(n, nc, proto);
+    if (!chain) {
+        return virtio_net_do_receive(nc, buf, size);
+    } else {
+        chain->stat.received++;
+        return virtio_net_rsc_receive4(chain, nc, buf, size);
+    }
 }
 
 static ssize_t virtio_net_receive(NetClientState *nc,
                                   const uint8_t *buf, size_t size)
 {
     VirtIONet *n;
+    struct virtio_net_hdr *h;
 
     n = qemu_get_nic_opaque(nc);
-    if (n->curr_guest_offloads & VIRTIO_NET_F_GUEST_RSC) {
+    if (n->curr_guest_offloads & (1ULL << VIRTIO_NET_F_GUEST_RSC)) {
+        h = (struct virtio_net_hdr *)buf;
+        h->coalesced = 0;
+        h->dup_ack = 0;
         return virtio_net_rsc_receive(nc, buf, size);
     } else {
         return virtio_net_do_receive(nc, buf, size);
@@ -1837,6 +2314,7 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp)
     nc = qemu_get_queue(n->nic);
     nc->rxfilter_notify_enabled = 1;
 
+    QTAILQ_INIT(&n->rsc_chains);
     n->qdev = dev;
     register_savevm(dev, "virtio-net", -1, VIRTIO_NET_VM_VERSION,
                     virtio_net_save, virtio_net_load, n);
@@ -1871,6 +2349,7 @@ static void virtio_net_device_unrealize(DeviceState *dev, Error **errp)
     g_free(n->vqs);
     qemu_del_nic(n->nic);
     virtio_cleanup(vdev);
+    virtio_net_rsc_cleanup(n);
 }
 
 static void virtio_net_instance_init(Object *obj)
@@ -1933,7 +2412,9 @@ static Property virtio_net_properties[] = {
     DEFINE_PROP_INT32("x-txburst", VirtIONet, net_conf.txburst, TX_BURST),
     DEFINE_PROP_STRING("tx", VirtIONet, net_conf.tx),
     DEFINE_PROP_BIT("guest_rsc", VirtIONet, host_features,
-                    VIRTIO_NET_F_GUEST_RSC, true),
+                    VIRTIO_NET_F_GUEST_RSC, false),
+    DEFINE_PROP_UINT32("rsc_interval", VirtIONet, rsc_timeout,
+                      VIRTIO_NET_RSC_INTERVAL),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h
index 0cabdb6..e995190 100644
--- a/include/hw/virtio/virtio-net.h
+++ b/include/hw/virtio/virtio-net.h
@@ -59,6 +59,8 @@ typedef struct VirtIONet {
     VirtIONetQueue *vqs;
     VirtQueue *ctrl_vq;
     NICState *nic;
+    QTAILQ_HEAD(, NetRscChain) rsc_chains;
+    uint32_t rsc_timeout;
     uint32_t tx_timeout;
     int32_t tx_burst;
     uint32_t has_vnet_hdr;
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 2b5b248..02f7d81 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -30,6 +30,8 @@
                                 (0x1ULL << VIRTIO_F_ANY_LAYOUT))
 
 struct VirtQueue;
+struct VirtIONet;
+typedef struct VirtIONet VirtIONet;
 
 static inline hwaddr vring_align(hwaddr addr,
                                              unsigned long align)
@@ -128,6 +130,79 @@ typedef struct VirtioDeviceClass {
     int (*load)(VirtIODevice *vdev, QEMUFile *f, int version_id);
 } VirtioDeviceClass;
 
+/* Coalesced packets type & status */
+typedef enum {
+    RSC_COALESCE,           /* Data been coalesced */
+    RSC_FINAL,              /* Will terminate current connection */
+    RSC_NO_MATCH,           /* No matched in the buffer pool */
+    RSC_BYPASS,             /* Packet to be bypass, not tcp, tcp ctrl, etc */
+    RSC_WANT                /* Data want to be coalesced */
+} COALESCE_STATUS;
+
+typedef struct NetRscStat {
+    uint32_t received;
+    uint32_t coalesced;
+    uint32_t over_size;
+    uint32_t cache;
+    uint32_t empty_cache;
+    uint32_t no_match_cache;
+    uint32_t win_update;
+    uint32_t no_match;
+    uint32_t tcp_syn;
+    uint32_t tcp_ctrl_drain;
+    uint32_t dup_ack;
+    uint32_t dup_ack1;
+    uint32_t dup_ack2;
+    uint32_t pure_ack;
+    uint32_t ack_out_of_win;
+    uint32_t data_out_of_win;
+    uint32_t data_out_of_order;
+    uint32_t data_after_pure_ack;
+    uint32_t bypass_not_tcp;
+    uint32_t tcp_option;
+    uint32_t tcp_all_opt;
+    uint32_t ip_frag;
+    uint32_t ip_hacked;
+    uint32_t ip_option;
+    uint32_t purge_failed;
+    uint32_t drain_failed;
+    uint32_t final_failed;
+    int64_t  timer;
+} NetRscStat;
+
+/* Rsc unit general info used to checking if can coalescing */
+typedef struct NetRscUnit {
+    void *ip;   /* ip header */
+    uint16_t *ip_plen;      /* data len pointer in ip header field */
+    struct tcp_header *tcp; /* tcp header */
+    uint16_t tcp_hdrlen;    /* tcp header len */
+    uint16_t payload;       /* pure payload without virtio/eth/ip/tcp */
+} NetRscUnit;
+
+/* Coalesced segmant */
+typedef struct NetRscSeg {
+    QTAILQ_ENTRY(NetRscSeg) next;
+    void *buf;
+    size_t size;
+    uint16_t packets;
+    uint16_t dup_ack_count;
+    bool is_coalesced;      /* need recal ipv4 header checksum, mark here */
+    NetRscUnit unit;
+    NetClientState *nc;
+} NetRscSeg;
+
+/* Chain is divided by protocol(ipv4/v6) and NetClientInfo */
+typedef struct NetRscChain {
+    QTAILQ_ENTRY(NetRscChain) next;
+    VirtIONet *n;                            /* VirtIONet */
+    uint16_t proto;
+    uint8_t  gso_type;
+    uint16_t max_payload;
+    QEMUTimer *drain_timer;
+    QTAILQ_HEAD(, NetRscSeg) buffers;
+    NetRscStat stat;
+} NetRscChain;
+
 void virtio_instance_init_common(Object *proxy_obj, void *data,
                                  size_t vdev_size, const char *vdev_name);
 
diff --git a/include/standard-headers/linux/virtio_net.h b/include/standard-headers/linux/virtio_net.h
index 5b95762..23f28aa 100644
--- a/include/standard-headers/linux/virtio_net.h
+++ b/include/standard-headers/linux/virtio_net.h
@@ -114,6 +114,8 @@ struct virtio_net_hdr {
 	__virtio16 gso_size;		/* Bytes to append to hdr_len per frame */
 	__virtio16 csum_start;	/* Position to start checksumming from */
 	__virtio16 csum_offset;	/* Offset after that to place checksum */
+	__virtio16 coalesced;
+	__virtio16 dup_ack;
 };
 
 /* This is the version of the header to use when the MRG_RXBUF
