pjsip_transport_management: Shutdown transport immediately on disconnect

The transport management code that checks for idle connections keeps a
reference to PJSIP's transport for IDLE_TIMEOUT milliseconds (32000 by
default). Because of this, if the transport is closed before this
timeout, the idle checking code will keep the transport from actually
being shutdown until the timeout expires.

Rather than passing the AO2 object to the scheduler task, we just pass
its key and look it up when it is time to potentially close the idle
connection. The other transport management code handles cleaning up
everything else for us.

Additionally, because we use the address of the transport when
generating its name, we concatenate an incrementing ID to the end of the
name to guarantee uniqueness.

Related to ASTERISK~28231

Change-Id: I02ee9f4073b6abca9169d30c47aa69b5e8ae9afb

res/res_pjsip/pjsip_transport_management.c

@@ -139,34 +139,62 @@ static int idle_sched_init_pj_thread(void)
 	return 0;
 }
 
+static struct monitored_transport *get_monitored_transport_by_name(const char *obj_name)
+{
+	struct ao2_container *transports;
+	struct monitored_transport *monitored = NULL;
+
+	transports = ao2_global_obj_ref(monitored_transports);
+	if (transports) {
+		monitored = ao2_find(transports, obj_name, OBJ_SEARCH_KEY);
+	}
+	ao2_cleanup(transports);
+
+	/* Caller is responsible for cleaning up reference */
+	return monitored;
+}
+
 static int idle_sched_cb(const void *data)
 {
-	struct monitored_transport *monitored = (struct monitored_transport *) data;
+	char *obj_name = (char *) data;
+	struct monitored_transport *monitored;
 
 	if (idle_sched_init_pj_thread()) {
-		ao2_ref(monitored, -1);
+		ast_free(obj_name);
 		return 0;
 	}
 
-	if (!monitored->sip_received) {
-		ast_log(LOG_NOTICE, "Shutting down transport '%s' since no request was received in %d seconds\n",
-			monitored->transport->info, IDLE_TIMEOUT / 1000);
-		pjsip_transport_shutdown(monitored->transport);
+	monitored = get_monitored_transport_by_name(obj_name);
+	if (monitored) {
+		if (!monitored->sip_received) {
+			ast_log(LOG_NOTICE, "Shutting down transport '%s' since no request was received in %d seconds\n",
+				monitored->transport->info, IDLE_TIMEOUT / 1000);
+			pjsip_transport_shutdown(monitored->transport);
+		}
+		ao2_ref(monitored, -1);
 	}
 
-	ao2_ref(monitored, -1);
+	ast_free(obj_name);
 	return 0;
 }
 
 static int idle_sched_cleanup(const void *data)
 {
-	struct monitored_transport *monitored = (struct monitored_transport *) data;
+	char *obj_name = (char *) data;
+	struct monitored_transport *monitored;
 
-	if (!idle_sched_init_pj_thread()) {
+	if (idle_sched_init_pj_thread()) {
+		ast_free(obj_name);
+		return 0;
+	}
+
+	monitored = get_monitored_transport_by_name(obj_name);
+	if (monitored) {
 		pjsip_transport_shutdown(monitored->transport);
+		ao2_ref(monitored, -1);
 	}
-	ao2_ref(monitored, -1);
 
+	ast_free(obj_name);
 	return 0;
 }
 
@@ -203,13 +231,13 @@ static void monitored_transport_state_callback(pjsip_transport *transport, pjsip
 			ao2_link(transports, monitored);
 
 			if (transport->dir == PJSIP_TP_DIR_INCOMING) {
-				/* Let the scheduler inherit the reference from allocation */
-				if (ast_sched_add_variable(sched, IDLE_TIMEOUT, idle_sched_cb, monitored, 1) < 0) {
-					/* Uh Oh.  Could not schedule the idle check.  Kill the transport. */
+				char *obj_name = ast_strdup(transport->obj_name);
+
+				if (!obj_name
+				   || ast_sched_add_variable(sched, IDLE_TIMEOUT, idle_sched_cb, obj_name, 1) < 0) {
+					/* Shut down the transport if anything fails */
 					pjsip_transport_shutdown(transport);
-				} else {
-					/* monitored ref successfully passed to idle_sched_cb() */
-					break;
+					ast_free(obj_name);
 				}
 			}
 			ao2_ref(monitored, -1);
@@ -324,23 +352,14 @@ static struct ast_sorcery_observer keepalive_global_observer = {
  */
 static pj_bool_t idle_monitor_on_rx_request(pjsip_rx_data *rdata)
 {
-	struct ao2_container *transports;
 	struct monitored_transport *idle_trans;
 
-	transports = ao2_global_obj_ref(monitored_transports);
-	if (!transports) {
-		return PJ_FALSE;
-	}
-
-	idle_trans = ao2_find(transports, rdata->tp_info.transport->obj_name, OBJ_SEARCH_KEY);
-	ao2_ref(transports, -1);
-	if (!idle_trans) {
-		return PJ_FALSE;
+	idle_trans = get_monitored_transport_by_name(rdata->tp_info.transport->obj_name);
+	if (idle_trans) {
+		idle_trans->sip_received = 1;
+		ao2_ref(idle_trans, -1);
 	}
 
-	idle_trans->sip_received = 1;
-	ao2_ref(idle_trans, -1);
-
 	return PJ_FALSE;
 }
 

res/res_pjsip_transport_websocket.c

@@ -41,6 +41,11 @@
 static int transport_type_wss;
 static int transport_type_wss_ipv6;
 
+/*!
+ * Used to ensure uniqueness among WS transport names
+ */
+static int ws_obj_name_serial;
+
 /*!
  * \brief Wrapper for pjsip_transport, for storing the WebSocket session
  */
@@ -163,8 +168,8 @@ static int transport_create(void *data)
 	}
 
 	/* Give websocket transport a unique name for its lifetime */
-	snprintf(newtransport->transport.obj_name, PJ_MAX_OBJ_NAME, "ws%p",
-		&newtransport->transport);
+	snprintf(newtransport->transport.obj_name, PJ_MAX_OBJ_NAME, "ws%p-%d",
+		&newtransport->transport, ast_atomic_fetchadd_int(&ws_obj_name_serial, 1));
 
 	newtransport->transport.endpt = endpt;