[Qemu-devel] [ Patch 2/2] virtio-net rsc: support coalescing ipv6 tcp traffic

[wexu]

From: Wei Xu <address@hidden>

Most things like ipv4 except there is a significant difference between ipv4
and ipv6, the fragment lenght in ipv4 header includes itself, while it's not
included for ipv6, thus means ipv6 can carry a real '65535' unit.

Signed-off-by: Wei Xu <address@hidden>
---
 hw/net/virtio-net.c        | 146 ++++++++++++++++++++++++++++++++++++++++-----
 include/hw/virtio/virtio.h |   5 +-
 2 files changed, 135 insertions(+), 16 deletions(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index c23b45f..ef61b74 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -52,9 +52,14 @@
 #define MAX_IP4_PAYLOAD (65535 - IP4_HDR_SZ)
 #define MAX_TCP_PAYLOAD 65535
 
-/* max payload with virtio header */
+#define IP6_HDR_SZ (sizeof(struct ip6_header))
+#define ETH_IP6_HDR_SZ (ETH_HDR_SZ + IP6_HDR_SZ)
+#define IP6_ADDR_SIZE   32      /* ipv6 saddr + daddr */
+#define MAX_IP6_PAYLOAD MAX_TCP_PAYLOAD
+
+/* ip6 max payload, payload in ipv6 don't include the  header */
 #define MAX_VIRTIO_PAYLOAD  (sizeof(struct virtio_net_hdr_mrg_rxbuf) \
-                                + ETH_HDR_SZ + MAX_TCP_PAYLOAD)
+                                + ETH_IP6_HDR_SZ + MAX_IP6_PAYLOAD)
 
 #define IP4_HEADER_LEN 5 /* header lenght value in ip header without option */
 
@@ -1722,14 +1727,27 @@ static void virtio_net_rsc_extract_unit4(NetRscChain 
*chain,
 {
     uint16_t ip_hdrlen;
 
-    unit->ip = (struct ip_header *)(buf + chain->hdr_size + ETH_HDR_SZ);
-    ip_hdrlen = ((0xF & unit->ip->ip_ver_len) << 2);
-    unit->ip_plen = &unit->ip->ip_len;
-    unit->tcp = (struct tcp_header *)(((uint8_t *)unit->ip) + ip_hdrlen);
+    unit->u_ip.ip = (struct ip_header *)(buf + chain->hdr_size + ETH_HDR_SZ);
+    ip_hdrlen = ((0xF & unit->u_ip.ip->ip_ver_len) << 2);
+    unit->ip_plen = &unit->u_ip.ip->ip_len;
+    unit->tcp = (struct tcp_header *)(((uint8_t *)unit->u_ip.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_extract_unit6(NetRscChain *chain,
+                                         const uint8_t *buf, NetRscUnit* unit)
+{
+    unit->u_ip.ip6 = (struct ip6_header *)(buf + chain->hdr_size + ETH_HDR_SZ);
+    unit->ip_plen = &(unit->u_ip.ip6->ip6_ctlun.ip6_un1.ip6_un1_plen);
+    unit->tcp = (struct tcp_header *)(((uint8_t *)unit->u_ip.ip6)\
+                                    + IP6_HDR_SZ);
+    unit->tcp_hdrlen = (htons(unit->tcp->th_offset_flags) & 0xF000) >> 10;
+    /* There is a difference between payload lenght in ipv4 and v6,
+       ip header is excluded in ipv6 */
+    unit->payload = htons(*unit->ip_plen) - unit->tcp_hdrlen;
+}
+
 static void virtio_net_rsc_ipv4_checksum(struct ip_header *ip)
 {
     uint32_t sum;
@@ -1743,7 +1761,10 @@ static size_t virtio_net_rsc_drain_seg(NetRscChain 
*chain, NetRscSeg *seg)
 {
     int ret;
 
-    virtio_net_rsc_ipv4_checksum(seg->unit.ip);
+    if ((chain->proto == ETH_P_IP) && seg->is_coalesced) {
+        virtio_net_rsc_ipv4_checksum(seg->unit.u_ip.ip);
+    }
+
     ret = virtio_net_do_receive(seg->nc, seg->buf, seg->size);
     QTAILQ_REMOVE(&chain->buffers, seg, next);
     g_free(seg->buf);
@@ -1807,7 +1828,11 @@ static void virtio_net_rsc_cache_buf(NetRscChain *chain, 
NetClientState *nc,
     QTAILQ_INSERT_TAIL(&chain->buffers, seg, next);
     chain->stat.cache++;
 
-    virtio_net_rsc_extract_unit4(chain, seg->buf, &seg->unit);
+    if (chain->proto == ETH_P_IP) {
+        virtio_net_rsc_extract_unit4(chain, seg->buf, &seg->unit);
+    } else {
+        virtio_net_rsc_extract_unit6(chain, seg->buf, &seg->unit);
+    }
 }
 
 static int32_t virtio_net_rsc_handle_ack(NetRscChain *chain, NetRscSeg *seg,
@@ -1930,8 +1955,8 @@ coalesce:
 static int32_t virtio_net_rsc_coalesce4(NetRscChain *chain, NetRscSeg *seg,
                         const uint8_t *buf, size_t size, NetRscUnit *unit)
 {
-    if ((unit->ip->ip_src ^ seg->unit.ip->ip_src)
-        || (unit->ip->ip_dst ^ seg->unit.ip->ip_dst)
+    if ((unit->u_ip.ip->ip_src ^ seg->unit.u_ip.ip->ip_src)
+        || (unit->u_ip.ip->ip_dst ^ seg->unit.u_ip.ip->ip_dst)
         || (unit->tcp->th_sport ^ seg->unit.tcp->th_sport)
         || (unit->tcp->th_dport ^ seg->unit.tcp->th_dport)) {
         chain->stat.no_match++;
@@ -1941,6 +1966,22 @@ static int32_t virtio_net_rsc_coalesce4(NetRscChain 
*chain, NetRscSeg *seg,
     return virtio_net_rsc_coalesce_data(chain, seg, buf, unit);
 }
 
+static int32_t virtio_net_rsc_coalesce6(NetRscChain *chain, NetRscSeg *seg,
+                        const uint8_t *buf, size_t size, NetRscUnit *unit)
+{
+    if (memcmp(&unit->u_ip.ip6->ip6_src, &seg->unit.u_ip.ip6->ip6_src,
+               sizeof(struct in6_address))
+        || memcmp(&unit->u_ip.ip6->ip6_dst, &seg->unit.u_ip.ip6->ip6_dst,
+                  sizeof(struct in6_address))
+        || (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,
@@ -1983,7 +2024,11 @@ static size_t virtio_net_rsc_do_coalesce(NetRscChain 
*chain, NetClientState *nc,
     NetRscSeg *seg, *nseg;
 
     QTAILQ_FOREACH_SAFE(seg, &chain->buffers, next, nseg) {
-        ret = virtio_net_rsc_coalesce4(chain, seg, buf, size, unit);
+        if (chain->proto == ETH_P_IP) {
+            ret = virtio_net_rsc_coalesce4(chain, seg, buf, size, unit);
+        } else {
+            ret = virtio_net_rsc_coalesce6(chain, seg, buf, size, unit);
+        }
 
         if (ret == RSC_FINAL) {
             if (virtio_net_rsc_drain_seg(chain, seg) == 0) {
@@ -2082,7 +2127,8 @@ static size_t virtio_net_rsc_receive4(void *opq, 
NetClientState* nc,
 
     chain = (NetRscChain *)opq;
     virtio_net_rsc_extract_unit4(chain, buf, &unit);
-    if (RSC_WANT != virtio_net_rsc_sanity_check4(chain, unit.ip, buf, size)) {
+    if (RSC_WANT != virtio_net_rsc_sanity_check4(chain,
+                                                 unit.u_ip.ip, buf, size)) {
         return virtio_net_do_receive(nc, buf, size);
     }
 
@@ -2102,13 +2148,74 @@ static size_t virtio_net_rsc_receive4(void *opq, 
NetClientState* nc,
     return virtio_net_rsc_do_coalesce(chain, nc, buf, size, &unit);
 }
 
+static int32_t virtio_net_rsc_sanity_check6(NetRscChain *chain, 
+                        struct ip6_header *ip, const uint8_t *buf, size_t size)
+{
+    uint16_t ip_len;
+
+    if (size < (chain->hdr_size + ETH_IP6_HDR_SZ + TCP_HDR_SZ)) {
+        return RSC_BYPASS;
+    }
+
+    if (((0xF0 & ip->ip6_ctlun.ip6_un1.ip6_un1_flow) >> 4)
+        != IP_HEADER_VERSION_6) {
+        return RSC_BYPASS;
+    }
+
+    /* Both option and protocol is checked in this */
+    if (ip->ip6_ctlun.ip6_un1.ip6_un1_nxt != IPPROTO_TCP) {
+        chain->stat.bypass_not_tcp++;
+        return RSC_BYPASS;
+    }
+
+    /* Sanity check */
+    ip_len = htons(ip->ip6_ctlun.ip6_un1.ip6_un1_plen);
+    if (ip_len < TCP_HDR_SZ
+        || ip_len > (size - chain->hdr_size - ETH_IP6_HDR_SZ)) {
+        chain->stat.ip_hacked++;
+        return RSC_BYPASS;
+    }
+
+    return RSC_WANT;
+}
+
+static size_t virtio_net_rsc_receive6(void *opq, NetClientState* nc,
+                                      const uint8_t *buf, size_t size)
+{
+    int32_t ret;
+    NetRscChain *chain;
+    NetRscUnit unit;
+
+    chain = (NetRscChain *)opq;
+    virtio_net_rsc_extract_unit6(chain, buf, &unit);
+    if (RSC_WANT != virtio_net_rsc_sanity_check6(chain,
+                                                 unit.u_ip.ip6, 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,
+                        ((chain->hdr_size + ETH_HDR_SZ) + 8), IP6_ADDR_SIZE,
+                        (chain->hdr_size + ETH_IP6_HDR_SZ), 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;
 
     /* Only handle IPv4/6 */
-    if (proto != (uint16_t)ETH_P_IP) {
+    if ((proto != (uint16_t)ETH_P_IP) && (proto != (uint16_t)ETH_P_IPV6)) {
         return NULL;
     }
 
@@ -2121,7 +2228,11 @@ static NetRscChain 
*virtio_net_rsc_lookup_chain(VirtIONet * n,
     chain = g_malloc(sizeof(*chain));
     chain->hdr_size = n->guest_hdr_len;
     chain->proto = proto;
-    chain->max_payload = MAX_IP4_PAYLOAD;
+    if (proto == (uint16_t)ETH_P_IP) {
+        chain->max_payload = MAX_IP4_PAYLOAD;
+    } else {
+        chain->max_payload = MAX_IP6_PAYLOAD;
+    }
     chain->drain_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
                                       virtio_net_rsc_purge, chain);
     memset(&chain->stat, 0, sizeof(chain->stat));
@@ -2153,7 +2264,12 @@ static ssize_t virtio_net_rsc_receive(NetClientState *nc,
         return virtio_net_do_receive(nc, buf, size);
     } else {
         chain->stat.received++;
-        return virtio_net_rsc_receive4(chain, nc, buf, size);
+
+        if (proto == (uint16_t)ETH_P_IP) {
+            return virtio_net_rsc_receive4(chain, nc, buf, size);
+        } else  {
+            return virtio_net_rsc_receive6(chain, nc, buf, size);
+        }
     }
 }
 
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 3b1dfa8..13d20a4 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -170,7 +170,10 @@ typedef struct NetRscStat {
 
 /* Rsc unit general info used to checking if can coalescing */
 typedef struct NetRscUnit {
-   struct ip_header *ip;   /* ip header */
+    union {
+        struct ip_header *ip;   /* ip header */
+        struct ip6_header *ip6; /* ip6 header */
+    } u_ip;
    uint16_t *ip_plen;      /* data len pointer in ip header field */
    struct tcp_header *tcp; /* tcp header */
    uint16_t tcp_hdrlen;    /* tcp header len */
-- 
2.5.0