[ovs-dev] [PATCH] conntrack: Fix tcp payload length in case multi-segments.

[Zhike Wang]

Signed-off-by: Zhike Wang <wangzk320 at 163.com>
---
 lib/conntrack-private.h | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/lib/conntrack-private.h b/lib/conntrack-private.h
index 590f139..1d21f6e 100644
--- a/lib/conntrack-private.h
+++ b/lib/conntrack-private.h
@@ -233,13 +233,17 @@ conn_update_expiration(struct conntrack *ct, struct conn *conn,
 static inline uint32_t
 tcp_payload_length(struct dp_packet *pkt)
 {
-    const char *tcp_payload = dp_packet_get_tcp_payload(pkt);
-    if (tcp_payload) {
-        return ((char *) dp_packet_tail(pkt) - dp_packet_l2_pad_size(pkt)
-                - tcp_payload);
-    } else {
-        return 0;
+    size_t l4_size = dp_packet_l4_size(pkt);
+
+    if (OVS_LIKELY(l4_size >= TCP_HEADER_LEN)) {
+        struct tcp_header *tcp = dp_packet_l4(pkt);
+        int tcp_len = TCP_OFFSET(tcp->tcp_ctl) * 4;
+
+        if (OVS_LIKELY(tcp_len >= TCP_HEADER_LEN && tcp_len <= l4_size)) {
+            return (l4_size - tcp_len);
+        }
     }
+    return 0;
 }
 
 #endif /* conntrack-private.h */
-- 
1.8.3.1