Make sure that the branch sent in CANCEL requests

matches the branch of the INVITE it is cancelling.

(closes issue #13381)
Reported by: atca_pres
Patches:
      13381v2.patch uploaded by putnopvut (license 60)
Tested by: atca_pres

(closes issue #13198)
Reported by: rickead2000
Tested by: rickead2000



git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@142218 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -973,6 +973,7 @@ static struct sip_pvt {
 	int authtries;				/*!< Times we've tried to authenticate */
 	int expiry;				/*!< How long we take to expire */
 	long branch;				/*!< The branch identifier of this session */
+	long invite_branch;			/*!< The branch used when we sent the initial INVITE */
 	char tag[11];				/*!< Our tag for this session */
 	int sessionid;				/*!< SDP Session ID */
 	int sessionversion;			/*!< SDP Session Version */
@@ -5980,7 +5981,10 @@ static int reqprep(struct sip_request *req, struct sip_pvt *p, int sipmethod, in
 		seqno = p->ocseq;
 	}
 	
-	if (newbranch) {
+	if (sipmethod == SIP_CANCEL) {
+		p->branch = p->invite_branch;
+		build_via(p);
+	} else if (newbranch) {
 		p->branch ^= ast_random();
 		build_via(p);
 	}
@@ -7128,6 +7132,7 @@ static int transmit_invite(struct sip_pvt *p, int sipmethod, int sdp, int init)
 	if (init) {		/* Seems like init always is 2 */
 		/* Bump branch even on initial requests */
 		p->branch ^= ast_random();
+		p->invite_branch = p->branch;
 		build_via(p);
 		if (init > 1)
 			initreqprep(&req, p, sipmethod);