[Qemu-devel] [PATCH V5 4/9] net/net.c: Add vnet_hdr support in SocketReadState

[Zhang Chen <zhangchen.fnst@cn.fujitsu.com>]

We add a flag to dicide whether net_fill_rstate() to read
the vnet_hdr_len or not.

Signed-off-by: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
Suggested-by: Jason Wang <jasowang@redhat.com>
---
 include/net/net.h   |  6 +++++-
 net/filter-mirror.c |  1 +
 net/net.c           | 33 ++++++++++++++++++++++++++++++---
 3 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/include/net/net.h b/include/net/net.h
index 70edfc0..6846b91 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -113,9 +113,13 @@ typedef struct NICState {
 } NICState;
 
 struct SocketReadState {
-    int state; /* 0 = getting length, 1 = getting data */
+    /* 0 = getting length, 1 = getting vnet header length, 2 = getting data */
+    int state;
+    /* This flag decide whether to read the vnet_hdr_len field */
+    bool vnet_hdr;
     uint32_t index;
     uint32_t packet_len;
+    uint32_t vnet_hdr_len;
     uint8_t buf[NET_BUFSIZE];
     SocketReadStateFinalize *finalize;
 };
diff --git a/net/filter-mirror.c b/net/filter-mirror.c
index 6c8579f..18992e9 100644
--- a/net/filter-mirror.c
+++ b/net/filter-mirror.c
@@ -266,6 +266,7 @@ static void filter_redirector_setup(NetFilterState *nf, Error **errp)
     }
 
     net_socket_rs_init(&s->rs, redirector_rs_finalize);
+    s->rs.vnet_hdr = s->vnet_hdr;
 
     if (s->indev) {
         chr = qemu_chr_find(s->indev);
diff --git a/net/net.c b/net/net.c
index a00a0c9..031cbb5 100644
--- a/net/net.c
+++ b/net/net.c
@@ -1607,8 +1607,10 @@ void net_socket_rs_init(SocketReadState *rs,
                         SocketReadStateFinalize *finalize)
 {
     rs->state = 0;
+    rs->vnet_hdr = false;
     rs->index = 0;
     rs->packet_len = 0;
+    rs->vnet_hdr_len = 0;
     memset(rs->buf, 0, sizeof(rs->buf));
     rs->finalize = finalize;
 }
@@ -1623,8 +1625,12 @@ int net_fill_rstate(SocketReadState *rs, const uint8_t *buf, int size)
     unsigned int l;
 
     while (size > 0) {
-        /* reassemble a packet from the network */
-        switch (rs->state) { /* 0 = getting length, 1 = getting data */
+        /* Reassemble a packet from the network.
+         * 0 = getting length.
+         * 1 = getting vnet header length.
+         * 2 = getting data.
+         */
+        switch (rs->state) {
         case 0:
             l = 4 - rs->index;
             if (l > size) {
@@ -1638,10 +1644,31 @@ int net_fill_rstate(SocketReadState *rs, const uint8_t *buf, int size)
                 /* got length */
                 rs->packet_len = ntohl(*(uint32_t *)rs->buf);
                 rs->index = 0;
-                rs->state = 1;
+                if (rs->vnet_hdr) {
+                    rs->state = 1;
+                } else {
+                    rs->state = 2;
+                    rs->vnet_hdr_len = 0;
+                }
             }
             break;
         case 1:
+            l = 4 - rs->index;
+            if (l > size) {
+                l = size;
+            }
+            memcpy(rs->buf + rs->index, buf, l);
+            buf += l;
+            size -= l;
+            rs->index += l;
+            if (rs->index == 4) {
+                /* got vnet header length */
+                rs->vnet_hdr_len = ntohl(*(uint32_t *)rs->buf);
+                rs->index = 0;
+                rs->state = 2;
+            }
+            break;
+        case 2:
             l = rs->packet_len - rs->index;
             if (l > size) {
                 l = size;
-- 
2.7.4