res_pjsip_session: Delay sending BYE if a re-INVITE transaction is in progress.

Given the scenario where a PJSIP channel is in a native RTP bridge with direct
media and the channel is then hung up the code will currently re-INVITE the channel
back to Asterisk and send a BYE at the same time. Many SIP implementations dislike
this greatly.

This change makes it so that if a re-INVITE transaction is in progress the BYE
is queued to occur after the completion of the transaction (be it through normal
means or a timeout).

Review: https://reviewboard.asterisk.org/r/4248/
........

Merged revisions 429409 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/certified/branches/13.1@429864 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_pjsip.c

@@ -1692,22 +1692,7 @@ static int hangup(void *data)
 	struct ast_sip_session *session = channel->session;
 	int cause = h_data->cause;
 
-	if (!session->defer_terminate) {
-		pj_status_t status;
-		pjsip_tx_data *packet = NULL;
-
-		if (session->inv_session->state == PJSIP_INV_STATE_NULL) {
-			pjsip_inv_terminate(session->inv_session, cause ? cause : 603, PJ_TRUE);
-		} else if (((status = pjsip_inv_end_session(session->inv_session, cause ? cause : 603, NULL, &packet)) == PJ_SUCCESS)
-			&& packet) {
-			if (packet->msg->type == PJSIP_RESPONSE_MSG) {
-				ast_sip_session_send_response(session, packet);
-			} else {
-				ast_sip_session_send_request(session, packet);
-			}
-		}
-	}
-
+	ast_sip_session_terminate(session, cause);
 	clear_session_and_channel(session, ast, pvt);
 	ao2_cleanup(channel);
 	ao2_cleanup(h_data);

include/asterisk/res_pjsip_session.h

@@ -433,6 +433,14 @@ struct ast_sip_session *ast_sip_session_create_outgoing(struct ast_sip_endpoint
 	struct ast_sip_contact *contact, const char *location, const char *request_user,
 	struct ast_format_cap *req_caps);
 
+/*!
+ * \brief Terminate a session and, if possible, send the provided response code
+ *
+ * \param session The session to terminate
+ * \param response The response code to use for termination if possible
+ */
+void ast_sip_session_terminate(struct ast_sip_session *session, int response);
+
 /*!
  * \brief Defer local termination of a session until remote side terminates, or an amount of time passes
  *

res/res_pjsip_session.c

@@ -528,6 +528,8 @@ static int send_delayed_request(struct ast_sip_session *session, struct ast_sip_
 	} else if (!strcmp(delay->method, "UPDATE")) {
 		ast_sip_session_refresh(session, delay->on_request_creation,
 				delay->on_sdp_creation, delay->on_response, AST_SIP_SESSION_REFRESH_METHOD_UPDATE, delay->generate_new_sdp);
+	} else if (!strcmp(delay->method, "BYE")) {
+		ast_sip_session_terminate(session, 0);
 	} else {
 		ast_log(LOG_WARNING, "Unexpected delayed %s request with no existing request structure\n", delay->method);
 		return -1;
@@ -1292,6 +1294,38 @@ struct ast_sip_session *ast_sip_session_create_outgoing(struct ast_sip_endpoint
 	return session;
 }
 
+void ast_sip_session_terminate(struct ast_sip_session *session, int response)
+{
+	pj_status_t status;
+	pjsip_tx_data *packet = NULL;
+
+	if (session->defer_terminate) {
+		return;
+	}
+
+	if (!response) {
+		response = 603;
+	}
+
+	if ((session->inv_session->state == PJSIP_INV_STATE_CONFIRMED) && session->inv_session->invite_tsx) {
+		ast_debug(3, "Delaying sending BYE to %s because of outstanding transaction...\n",
+				ast_sorcery_object_get_id(session->endpoint));
+		/* If this is delayed the only thing that will happen is a BYE request so we don't
+		 * actually need to store the response code for when it happens.
+		 */
+		delay_request(session, NULL, NULL, NULL, 0, "BYE");
+	} else if (session->inv_session->state == PJSIP_INV_STATE_NULL) {
+		pjsip_inv_terminate(session->inv_session, response, PJ_TRUE);
+	} else if (((status = pjsip_inv_end_session(session->inv_session, response, NULL, &packet)) == PJ_SUCCESS)
+		&& packet) {
+		if (packet->msg->type == PJSIP_RESPONSE_MSG) {
+			ast_sip_session_send_response(session, packet);
+		} else {
+			ast_sip_session_send_request(session, packet);
+		}
+	}
+}
+
 static int session_termination_task(void *data)
 {
 	RAII_VAR(struct ast_sip_session *, session, data, ao2_cleanup);

res/res_pjsip_session.exports.in

@@ -1,5 +1,6 @@
 {
 	global:
+		LINKER_SYMBOL_PREFIXast_sip_session_terminate;
 		LINKER_SYMBOL_PREFIXast_sip_session_defer_termination;
 		LINKER_SYMBOL_PREFIXast_sip_session_register_sdp_handler;
 		LINKER_SYMBOL_PREFIXast_sip_session_unregister_sdp_handler;