Improve call forwarding reporting, especially with regards to ARI.

This patch addresses a few issues:

1) The order of Dial events have been changed when performing a call forward.
   The order has now been altered to
    1) Dial begins dialing channel A.
    2) When A forwards the call to B, we issue the dial end event to channel
       A, indicating the dial is being canceled due to a forward to B.
    3) When the call to channel B occurs, we then issue a new dial begin to
       channel B.

2) Call forwards are now reported on the calling channel, not the peer channel.

3) AMI DialEnd events have been altered to display the extension the call is
   being forwarded to when relevant.

4) You can now get the values of channel variables for channels that are not
   currently in the Stasis application. This brings the retrieval of channel
   variables more in line with the rest of channel read operations since they
   may be performed on channels not in Stasis.

ASTERISK-24134 #close
Reported by Matt Jordan

ASTERISK-24138 #close
Reported by Matt Jordan

Patches:
	forward-shenanigans.diff uploaded by Matt Jordan (License #6283)

Review: https://reviewboard.asterisk.org/r/3899
........

Merged revisions 420794 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@421310 65c4cc65-6c06-0410-ace0-fbb531ad65f3

CHANGES

@@ -280,6 +280,10 @@ AMI
  * The AMI action PJSIPShowEndpoint now includes ContactStatusDetail sections
    that give information on Asterisk's attempts to qualify the endpoint.
 
+ * The DialEnd event will now contain a Forward header if the dial is ending
+   due to the call being forwarded. The contents of the Forward header is the
+   extension in the number to which the call is being forwarded.
+
 CEL
 ------------------
  * The "bridge_technology" extra field key has been added to BRIDGE_ENTER

apps/app_dial.c

@@ -895,6 +895,7 @@ static void do_forward(struct chanlist *o, struct cause_args *num,
 				tech, stuff, cause);
 	}
 	if (!c) {
+		ast_channel_publish_dial(in, original, stuff, "BUSY");
 		ast_clear_flag64(o, DIAL_STILLGOING);
 		handle_cause(cause, num);
 		ast_hangup(original);
@@ -995,16 +996,18 @@ static void do_forward(struct chanlist *o, struct cause_args *num,
 		if (ast_call(c, stuff, 0)) {
 			ast_log(LOG_NOTICE, "Forwarding failed to dial '%s/%s'\n",
 				tech, stuff);
+			ast_channel_publish_dial(in, original, stuff, "CONGESTION");
 			ast_clear_flag64(o, DIAL_STILLGOING);
 			ast_hangup(original);
 			ast_hangup(c);
 			c = o->chan = NULL;
 			num->nochan++;
 		} else {
-			ast_channel_publish_dial(in, c, stuff, NULL);
 			ast_channel_publish_dial_forward(in, original, c, NULL, "CANCEL",
 				ast_channel_call_forward(original));
 
+			ast_channel_publish_dial(in, c, stuff, NULL);
+
 			/* Hangup the original channel now, in case we needed it */
 			ast_hangup(original);
 		}

include/asterisk/stasis_app.h

@@ -553,15 +553,6 @@ int stasis_app_control_unmute(struct stasis_app_control *control, unsigned int d
  */
 int stasis_app_control_answer(struct stasis_app_control *control);
 
-/*!
- * \brief Get the value of a variable on the channel associated with this control.
- * \param control Control for \c res_stasis.
- * \param variable The name of the variable.
- *
- * \return The value of the variable.  The returned variable must be freed.
- */
-char *stasis_app_control_get_channel_var(struct stasis_app_control *control, const char *variable);
-
 /*!
  * \brief Set a variable on the channel associated with this control to value.
  * \param control Control for \c res_stasis.

main/manager_channels.c

@@ -185,6 +185,10 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 						</enum>
 					</enumlist>
 				</parameter>
+				<parameter name="Forward" required="false">
+					<para>If the call was forwarded, where the call was
+					forwarded to.</para>
+				</parameter>
 			</syntax>
 			<see-also>
 				<ref type="application">Dial</ref>
@@ -986,6 +990,7 @@ static void channel_dial_cb(void *data, struct stasis_subscription *sub,
 	struct ast_multi_channel_blob *obj = stasis_message_data(message);
 	const char *dialstatus;
 	const char *dialstring;
+	const char *forward;
 	struct ast_channel_snapshot *caller;
 	struct ast_channel_snapshot *peer;
 	RAII_VAR(struct ast_str *, caller_event_string, NULL, ast_free);
@@ -1007,6 +1012,7 @@ static void channel_dial_cb(void *data, struct stasis_subscription *sub,
 
 	dialstatus = ast_json_string_get(ast_json_object_get(ast_multi_channel_blob_get_json(obj), "dialstatus"));
 	dialstring = ast_json_string_get(ast_json_object_get(ast_multi_channel_blob_get_json(obj), "dialstring"));
+	forward = ast_json_string_get(ast_json_object_get(ast_multi_channel_blob_get_json(obj), "forward"));
 	if (ast_strlen_zero(dialstatus)) {
 		manager_event(EVENT_FLAG_CALL, "DialBegin",
 				"%s"
@@ -1016,12 +1022,16 @@ static void channel_dial_cb(void *data, struct stasis_subscription *sub,
 				ast_str_buffer(peer_event_string),
 				S_OR(dialstring, "unknown"));
 	} else {
+		int forwarded = !ast_strlen_zero(forward);
+
 		manager_event(EVENT_FLAG_CALL, "DialEnd",
 				"%s"
 				"%s"
+				"%s%s%s"
 				"DialStatus: %s\r\n",
 				caller_event_string ? ast_str_buffer(caller_event_string) : "",
 				ast_str_buffer(peer_event_string),
+				forwarded ? "Forward: " : "", S_OR(forward, ""), forwarded ? "\r\n" : "",
 				S_OR(dialstatus, "unknown"));
 	}
 

main/stasis_channels.c

@@ -288,11 +288,6 @@ static void channel_blob_dtor(void *obj)
 	ast_json_unref(event->blob);
 }
 
-/*! \brief Dummy callback for receiving events */
-static void dummy_event_cb(void *data, struct stasis_subscription *sub, struct stasis_message *message)
-{
-}
-
 void ast_channel_publish_dial_forward(struct ast_channel *caller, struct ast_channel *peer,
 	struct ast_channel *forwarded, const char *dialstring, const char *dialstatus,
 	const char *forward)
@@ -362,14 +357,7 @@ void ast_channel_publish_dial_forward(struct ast_channel *caller, struct ast_cha
 		return;
 	}
 
-	if (forwarded) {
-		struct stasis_subscription *subscription = stasis_subscribe(ast_channel_topic(peer), dummy_event_cb, NULL);
-
-		stasis_publish(ast_channel_topic(peer), msg);
-		stasis_unsubscribe_and_join(subscription);
-	} else {
-		publish_message_for_channel_topics(msg, caller);
-	}
+	publish_message_for_channel_topics(msg, caller);
 }
 
 void ast_channel_publish_dial(struct ast_channel *caller, struct ast_channel *peer,

res/ari/resource_channels.c

@@ -928,7 +928,8 @@ void ast_ari_channels_get_channel_var(struct ast_variable *headers,
 {
 	RAII_VAR(struct ast_json *, json, NULL, ast_json_unref);
 	RAII_VAR(struct stasis_app_control *, control, NULL, ao2_cleanup);
-	RAII_VAR(char *, value, NULL, ast_free);
+	RAII_VAR(struct ast_str *, value, ast_str_create(32), ast_free);
+	RAII_VAR(struct ast_channel *, channel, NULL, ast_channel_cleanup);
 
 	ast_assert(response != NULL);
 
@@ -939,15 +940,41 @@ void ast_ari_channels_get_channel_var(struct ast_variable *headers,
 		return;
 	}
 
-	control = find_control(response, args->channel_id);
-	if (control == NULL) {
-		/* response filled in by find_control */
+	if (ast_strlen_zero(args->channel_id)) {
+		ast_ari_response_error(
+			response, 400, "Bad Request",
+			"Channel ID is required");
+		return;
+	}
+
+	channel = ast_channel_get_by_name(args->channel_id);
+	if (!channel) {
+		ast_ari_response_error(
+			response, 404, "Channel Not Found",
+			"Provided channel was not found");
 		return;
 	}
 
-	value = stasis_app_control_get_channel_var(control, args->variable);
+	/* You may be tempted to lock the channel you're about to read from. You
+	 * would be wrong. Some dialplan functions put the channel into
+	 * autoservice, which deadlocks if the channel is already locked.
+	 * ast_str_retrieve_variable() does its own locking, and the dialplan
+	 * functions need to as well. We should be fine without the lock.
+	 */
+
+	if (args->variable[strlen(args->variable) - 1] == ')') {
+		if (ast_func_read2(channel, args->variable, &value, 0)) {
+			ast_ari_response_alloc_failed(response);
+			return;
+		}
+	} else {
+		if (!ast_str_retrieve_variable(&value, 0, channel, NULL, args->variable)) {
+			ast_ari_response_alloc_failed(response);
+			return;
+		}
+	}
 
-	if (!(json = ast_json_pack("{s: s}", "value", S_OR(value, "")))) {
+	if (!(json = ast_json_pack("{s: s}", "value", S_OR(ast_str_buffer(value), "")))) {
 		ast_ari_response_alloc_failed(response);
 		return;
 	}

res/res_pjsip_pubsub.c

@@ -2032,10 +2032,13 @@ int ast_sip_subscription_notify(struct ast_sip_subscription *sub, void *notify_d
 	if (sub->tree->notification_batch_interval) {
 		return schedule_notification(sub->tree);
 	} else {
+		int res;
 		/* See the note in pubsub_on_rx_refresh() for why sub->tree is refbumped here */
 		ao2_ref(sub->tree, +1);
-		return send_notify(sub->tree, 0);
+		res = send_notify(sub->tree, 0);
 		ao2_ref(sub->tree, -1);
+		
+		return res;
 	}
 }
 

res/stasis/app.c

@@ -1073,9 +1073,7 @@ static int unsubscribe(struct stasis_app *app, const char *kind, const char *id,
 
 	forwards = ao2_find(app->forwards, id, OBJ_SEARCH_KEY | OBJ_NOLOCK);
 	if (!forwards) {
-		ast_log(LOG_WARNING,
-			"App '%s' not subscribed to %s '%s'\n",
-			app->name, kind, id);
+		ast_debug(3, "App '%s' not subscribed to %s '%s'\n", app->name, kind, id);
 		return -1;
 	}
 	forwards->interested--;

res/stasis/control.c

@@ -565,34 +565,6 @@ int stasis_app_control_unmute(struct stasis_app_control *control, unsigned int d
 	return 0;
 }
 
-char *stasis_app_control_get_channel_var(struct stasis_app_control *control, const char *variable)
-{
-	RAII_VAR(struct ast_str *, tmp, ast_str_create(32), ast_free);
-
-	/* You may be tempted to lock the channel you're about to read from. You
-	 * would be wrong. Some dialplan functions put the channel into
-	 * autoservice, which deadlocks if the channel is already locked.
-	 * ast_str_retrieve_variable() does its own locking, and the dialplan
-	 * functions need to as well. We should be fine without the lock.
-	 */
-
-	if (!tmp) {
-		return NULL;
-	}
-
-	if (variable[strlen(variable) - 1] == ')') {
-		if (ast_func_read2(control->channel, variable, &tmp, 0)) {
-			return NULL;
-		}
-	} else {
-		if (!ast_str_retrieve_variable(&tmp, 0, control->channel, NULL, variable)) {
-			return NULL;
-		}
-	}
-
-	return ast_strdup(ast_str_buffer(tmp));
-}
-
 int stasis_app_control_set_channel_var(struct stasis_app_control *control, const char *variable, const char *value)
 {
 	return pbx_builtin_setvar_helper(control->channel, variable, value);