[svn-commits] mmichelson: trunk r202343 - in /trunk: ./ channels/chan_sip.c

[SVN commits to the Digium repositories]

Author: mmichelson
Date: Mon Jun 22 09:58:24 2009
New Revision: 202343

URL: http://svn.asterisk.org/svn-view/asterisk?view=rev&rev=202343
Log:
Merged revisions 202341-202342 via svnmerge from 
https://origsvn.digium.com/svn/asterisk/branches/1.4

........
  r202341 | mmichelson | 2009-06-22 09:42:55 -0500 (Mon, 22 Jun 2009) | 26 lines
  
  Fix a situation in which Asterisk would not stop retransmitting 487s.
  
  If a CANCEL were received by Asterisk, we would send a 487 in response
  to the original INVITE and a 200 OK for the CANCEL. If there were a network
  hiccup which caused the 200 OK and the 487 to be lost, then the UA communicating
  with Asterisk may try to retransmit its CANCEL. Asterisk's response to this used
  to be to try sending another 487 to the canceled INVITE and another 200 OK to the
  CANCEL.
  
  The problem here is that the originally-sent 487 was sent "reliably" meaning that
  it will be retransmitted until it is received properly. So when we receive the second
  CANCEL it is likely that the first batch of 487s we sent is still going strong and
  reaches the UA. The result was that the second set of 487s would be retransmitted
  constantly until the maximum number of retries had been reached.
  
  The fix for this is that if we receive a second CANCEL for an INVITE, then we cancel
  the retransmission of the first set of 487s and start a second set. This causes the
  dialog to be terminated reasonably.
  
  (closes issue #14584)
  Reported by: klaus3000
  Patches:
        14584_v2.patch uploaded by mmichelson (license 60)
  Tested by: klaus3000
........
  r202342 | mmichelson | 2009-06-22 09:44:58 -0500 (Mon, 22 Jun 2009) | 3 lines
  
  Remove an extra debug line left from previous commit.
........

Modified:
    trunk/   (props changed)
    trunk/channels/chan_sip.c

Propchange: trunk/
------------------------------------------------------------------------------
Binary property 'branch-1.4-merged' - no diff available.

Modified: trunk/channels/chan_sip.c
URL: http://svn.asterisk.org/svn-view/asterisk/trunk/channels/chan_sip.c?view=diff&rev=202343&r1=202342&r2=202343
==============================================================================
--- trunk/channels/chan_sip.c (original)
+++ trunk/channels/chan_sip.c Mon Jun 22 09:58:24 2009
@@ -1930,6 +1930,7 @@
 	int seqno;				/*!< Sequence number */
 	char is_resp;				/*!< 1 if this is a response packet (e.g. 200 OK), 0 if it is a request */
 	char is_fatal;				/*!< non-zero if there is a fatal error */
+	int response_code;		/*!< If this is a response, the response code */
 	struct sip_pvt *owner;			/*!< Owner AST call */
 	int retransid;				/*!< Retransmission ID */
 	int timer_a;				/*!< SIP timer A, retransmission timer */
@@ -3727,6 +3728,7 @@
 	struct sip_pkt *pkt = NULL;
 	int siptimer_a = DEFAULT_RETRANS;
 	int xmitres = 0;
+	int respid;
 
 	if (sipmethod == SIP_INVITE) {
 		/* Note this is a pending invite */
@@ -3763,6 +3765,12 @@
 	pkt->owner = dialog_ref(p, "__sip_reliable_xmit: setting pkt->owner");
 	pkt->next = p->packets;
 	p->packets = pkt;	/* Add it to the queue */
+	if (resp) {
+		/* Parse out the response code */
+		if (sscanf(ast_str_buffer(pkt->data), "SIP/2.0 %d", &respid) == 1) {
+			pkt->response_code = respid;
+		}
+	}
 	pkt->timer_t1 = p->timer_t1;	/* Set SIP timer T1 */
 	pkt->retransid = -1;
 	if (pkt->timer_t1)
@@ -21103,6 +21111,30 @@
 	else
 		sip_scheddestroy(p, DEFAULT_TRANS_TIMEOUT);
 	if (p->initreq.len > 0) {
+		struct sip_pkt *pkt, *prev_pkt;
+		/* If the CANCEL we are receiving is a retransmission, and we already have scheduled
+		 * a reliable 487, then we don't want to schedule another one on top of the previous
+		 * one.
+		 *
+		 * As odd as this may sound, we can't rely on the previously-transmitted "reliable" 
+		 * response in this situation. What if we've sent all of our reliable responses 
+		 * already and now all of a sudden, we get this second CANCEL?
+		 *
+		 * The only way to do this correctly is to cancel our previously-scheduled reliably-
+		 * transmitted response and send a new one in its place.
+		 */
+		for (pkt = p->packets, prev_pkt = NULL; pkt; prev_pkt = pkt, pkt = pkt->next) {
+			if (pkt->seqno == p->lastinvite && pkt->response_code == 487) {
+				AST_SCHED_DEL(sched, pkt->retransid);
+				if (prev_pkt) {
+					prev_pkt->next = pkt->next;
+				} else {
+					p->packets = pkt->next;
+				}
+				ast_free(pkt);
+				break;
+			}
+		}
 		transmit_response_reliable(p, "487 Request Terminated", &p->initreq);
 		transmit_response(p, "200 OK", req);
 		return 1;