stream/tcp: update ack handling logic

Only update the ack value of a session for regular packets when
the ACK bit is set.

(cherry picked from commit 0d81173d6e912f4be9e3e8f7593d779d8ffed52f)

diff --git a/src/stream-tcp.c b/src/stream-tcp.c
index 8b5be8669b9e02bac39e8ebfbf9c5dfb3ba6ad48..b6d43e3194cdb76fe77f4277872e9617df5a2fb0 100644 (file)
--- a/src/stream-tcp.c
+++ b/src/stream-tcp.c
@@ -2367,7 +2367,8 @@ static int HandleEstablishedPacketToServer(ThreadVars *tv, TcpSession *ssn, Pack
                     ssn->server.window);
 
         /* Check if the ACK value is sane and inside the window limit */
-        StreamTcpUpdateLastAck(ssn, &ssn->server, TCP_GET_ACK(p));
+        if (p->tcph->th_flags & TH_ACK)
+            StreamTcpUpdateLastAck(ssn, &ssn->server, TCP_GET_ACK(p));
         SCLogDebug("ack %u last_ack %u next_seq %u", TCP_GET_ACK(p), ssn->server.last_ack, ssn->server.next_seq);
 
         if (ssn->flags & STREAMTCP_FLAG_TIMESTAMP) {
@@ -2521,7 +2522,8 @@ static int HandleEstablishedPacketToClient(ThreadVars *tv, TcpSession *ssn, Pack
         SCLogDebug("ssn %p: ssn->client.window %"PRIu32"", ssn,
                     ssn->client.window);
 
-        StreamTcpUpdateLastAck(ssn, &ssn->client, TCP_GET_ACK(p));
+        if (p->tcph->th_flags & TH_ACK)
+            StreamTcpUpdateLastAck(ssn, &ssn->client, TCP_GET_ACK(p));
 
         if (ssn->flags & STREAMTCP_FLAG_TIMESTAMP) {
             StreamTcpHandleTimestamp(ssn, p);
@@ -2830,7 +2832,8 @@ static int StreamTcpHandleFin(ThreadVars *tv, StreamTcpThread *stt,
                     ssn->client.next_seq);
         ssn->server.window = TCP_GET_WINDOW(p) << ssn->server.wscale;
 
-        StreamTcpUpdateLastAck(ssn, &ssn->server, TCP_GET_ACK(p));
+        if (p->tcph->th_flags & TH_ACK)
+            StreamTcpUpdateLastAck(ssn, &ssn->server, TCP_GET_ACK(p));
 
         if (ssn->flags & STREAMTCP_FLAG_TIMESTAMP) {
             StreamTcpHandleTimestamp(ssn, p);
@@ -2877,7 +2880,8 @@ static int StreamTcpHandleFin(ThreadVars *tv, StreamTcpThread *stt,
                     ssn->server.next_seq);
         ssn->client.window = TCP_GET_WINDOW(p) << ssn->client.wscale;
 
-        StreamTcpUpdateLastAck(ssn, &ssn->client, TCP_GET_ACK(p));
+        if (p->tcph->th_flags & TH_ACK)
+            StreamTcpUpdateLastAck(ssn, &ssn->client, TCP_GET_ACK(p));
 
         if (ssn->flags & STREAMTCP_FLAG_TIMESTAMP) {
             StreamTcpHandleTimestamp(ssn, p);
@@ -3110,7 +3114,8 @@ static int StreamTcpPacketStateFinWait1(ThreadVars *tv, Packet *p,
                 ssn->server.window = TCP_GET_WINDOW(p) << ssn->server.wscale;
             }
 
-            StreamTcpUpdateLastAck(ssn, &ssn->server, TCP_GET_ACK(p));
+            if (p->tcph->th_flags & TH_ACK)
+                StreamTcpUpdateLastAck(ssn, &ssn->server, TCP_GET_ACK(p));
 
             if (ssn->flags & STREAMTCP_FLAG_TIMESTAMP) {
                 StreamTcpHandleTimestamp(ssn, p);
@@ -3165,7 +3170,8 @@ static int StreamTcpPacketStateFinWait1(ThreadVars *tv, Packet *p,
                 ssn->client.window = TCP_GET_WINDOW(p) << ssn->client.wscale;
             }
 
-            StreamTcpUpdateLastAck(ssn, &ssn->client, TCP_GET_ACK(p));
+            if (p->tcph->th_flags & TH_ACK)
+                StreamTcpUpdateLastAck(ssn, &ssn->client, TCP_GET_ACK(p));
 
             if (ssn->flags & STREAMTCP_FLAG_TIMESTAMP) {
                 StreamTcpHandleTimestamp(ssn, p);
@@ -3448,7 +3454,8 @@ static int StreamTcpPacketStateFinWait2(ThreadVars *tv, Packet *p,
                 ssn->server.window = TCP_GET_WINDOW(p) << ssn->server.wscale;
             }
 
-            StreamTcpUpdateLastAck(ssn, &ssn->server, TCP_GET_ACK(p));
+            if (p->tcph->th_flags & TH_ACK)
+                StreamTcpUpdateLastAck(ssn, &ssn->server, TCP_GET_ACK(p));
 
             if (ssn->flags & STREAMTCP_FLAG_TIMESTAMP) {
                 StreamTcpHandleTimestamp(ssn, p);
@@ -3502,7 +3509,8 @@ static int StreamTcpPacketStateFinWait2(ThreadVars *tv, Packet *p,
                 ssn->client.window = TCP_GET_WINDOW(p) << ssn->client.wscale;
             }
 
-            StreamTcpUpdateLastAck(ssn, &ssn->client, TCP_GET_ACK(p));
+            if (p->tcph->th_flags & TH_ACK)
+                StreamTcpUpdateLastAck(ssn, &ssn->client, TCP_GET_ACK(p));
 
             if (ssn->flags & STREAMTCP_FLAG_TIMESTAMP) {
                 StreamTcpHandleTimestamp(ssn, p);
@@ -3919,7 +3927,8 @@ static int StreamTcpPacketStateCloseWait(ThreadVars *tv, Packet *p,
             if (!retransmission)
                 ssn->server.window = TCP_GET_WINDOW(p) << ssn->server.wscale;
 
-            StreamTcpUpdateLastAck(ssn, &ssn->server, TCP_GET_ACK(p));
+            if (p->tcph->th_flags & TH_ACK)
+                StreamTcpUpdateLastAck(ssn, &ssn->server, TCP_GET_ACK(p));
 
             if (ssn->flags & STREAMTCP_FLAG_TIMESTAMP) {
                 StreamTcpHandleTimestamp(ssn, p);
@@ -3971,7 +3980,8 @@ static int StreamTcpPacketStateCloseWait(ThreadVars *tv, Packet *p,
                 ssn->client.window = TCP_GET_WINDOW(p) << ssn->client.wscale;
             }
 
-            StreamTcpUpdateLastAck(ssn, &ssn->client, TCP_GET_ACK(p));
+            if (p->tcph->th_flags & TH_ACK)
+                StreamTcpUpdateLastAck(ssn, &ssn->client, TCP_GET_ACK(p));
 
             if (ssn->flags & STREAMTCP_FLAG_TIMESTAMP) {
                 StreamTcpHandleTimestamp(ssn, p);