From Martin Mathieson:

This patch further tightens up testing for resent packets.
It now always compares the method.  I've seen examples where the called 
party hangs up, and chooses the same CSeq for the BYE as the calling 
party chose for the INVITE.

svn path=/trunk/; revision=17408

1 files changed, 14 insertions, 7 deletions

diff --git a/epan/dissectors/packet-sip.c b/epan/dissectors/packet-sip.c
index 7a05006e55..a5163dfe1e 100644
--- a/epan/dissectors/packet-sip.c
+++ b/epan/dissectors/packet-sip.c
@@ -492,6 +492,7 @@ typedef struct
 {
 	guint32 cseq;
 	transaction_state_t transaction_state;
+	gchar method[MAX_CSEQ_METHOD_SIZE];
 	guint32 response_code;
 	gint frame_number;
 } sip_hash_value;
@@ -2095,6 +2096,8 @@ guint sip_is_packet_resend(packet_info *pinfo,
 		p_key->source_port = pinfo->srcport;
 
 		p_val->cseq = cseq_number;
+		strncpy(&p_val->method, cseq_method, MAX_CSEQ_METHOD_SIZE-1);
+		p_val->method[MAX_CSEQ_METHOD_SIZE] = '\0';
 		p_val->transaction_state = nothing_seen;
 		p_val->frame_number = 0;
 
@@ -2109,20 +2112,24 @@ guint sip_is_packet_resend(packet_info *pinfo,
 	/******************************************/
 	/* Is it a resend???                      */
 
-	/* Does this look like a resent request (discount ACK, CANCEL) ? */
+	/* Does this look like a resent request (discount ACK, CANCEL, or a
+	   different method from the original one) ? */
+
 	if ((line_type == REQUEST_LINE) && (cseq_number == cseq_to_compare) &&
-		(p_val->transaction_state == request_seen) &&
-		(strcmp(cseq_method, "ACK") != 0) &&
-		(strcmp(cseq_method, "CANCEL") != 0))
+	    (p_val->transaction_state == request_seen) &&
+	    (strcmp(cseq_method, p_val->method) == 0) &&
+	    (strcmp(cseq_method, "ACK") != 0) &&
+	    (strcmp(cseq_method, "CANCEL") != 0))
 	{
 		result = p_val->frame_number;
 	}
 
 	/* Does this look like a resent final response ? */
 	if ((line_type == STATUS_LINE) && (cseq_number == cseq_to_compare) &&
-		(p_val->transaction_state == final_response_seen) &&
-		(stat_info->response_code >= 200) &&
-		(stat_info->response_code == p_val->response_code))
+	    (p_val->transaction_state == final_response_seen) &&
+	    (strcmp(cseq_method, p_val->method) == 0) &&
+	    (stat_info->response_code >= 200) &&
+	    (stat_info->response_code == p_val->response_code))
 	{
 		result = p_val->frame_number;
 	}