handle special case were "200 Ok" to pending INVITE never receives ACK
authorDavid Vossel <dvossel@digium.com>
Wed, 14 Jul 2010 19:51:08 +0000 (19:51 +0000)
committerDavid Vossel <dvossel@digium.com>
Wed, 14 Jul 2010 19:51:08 +0000 (19:51 +0000)
Unlike most responses, the 200 Ok to a pending INVITE Request is
acknowledged by an ACK Request.  If the ACK Request for this Response is not received
the previous behavior was to immediately destroy the dialog and hangup
the channel. Now in an effort to be more RFC compliant, instead of immediately
destroying the dialog during this special case, termination is done with a BYE Request
as the dialog is technically confirmed when the 200 Ok is sent even if the ACK is
never received.  The behavior of immediately hanging up the channel remains.
This only affects how dialog termination proceeds for this one special case.

RFC 3261 section 13.3.1.4
"If the server retransmits the 2xx response for 64*T1 seconds without receiving
an ACK, the dialog is confirmed, but the session SHOULD be terminated.  This is
accomplished with a BYE, as described in Section 15."

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@276439 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

index e68fc73..6887e81 100644 (file)
@@ -3339,8 +3339,26 @@ static int retrans_pkt(const void *data)
                        pkt->owner->owner->hangupcause = AST_CAUSE_NO_USER_RESPONSE;
                }
                if (pkt->owner->owner) {
-                       sip_alreadygone(pkt->owner);
                        ast_log(LOG_WARNING, "Hanging up call %s - no reply to our critical packet (see doc/sip-retransmit.txt).\n", pkt->owner->callid);
+
+                       if (pkt->is_resp &&
+                               (pkt->response_code >= 200) &&
+                               (pkt->response_code < 300) &&
+                               pkt->owner->pendinginvite &&
+                               ast_test_flag(&pkt->owner->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED)) {
+                               /* This is a timeout of the 2XX response to a pending INVITE.  In this case terminate the INVITE
+                                * transaction just as if we received the ACK, but immediately hangup with a BYE (sip_hangup
+                                * will send the BYE as long as the dialog is not set as "alreadygone")
+                                * RFC 3261 section 13.3.1.4.
+                                * "If the server retransmits the 2xx response for 64*T1 seconds without receiving
+                                * an ACK, the dialog is confirmed, but the session SHOULD be terminated.  This is
+                                * accomplished with a BYE, as described in Section 15." */
+                               pkt->owner->invitestate = INV_TERMINATED;
+                               pkt->owner->pendinginvite = 0;
+                       } else {
+                               /* there is nothing left to do, mark the dialog as gone */
+                               sip_alreadygone(pkt->owner);
+                       }
                        ast_queue_hangup_with_cause(pkt->owner->owner, AST_CAUSE_PROTOCOL_ERROR);
                        ast_channel_unlock(pkt->owner->owner);
                } else {