bus: Add a handle_vips() hook invoked after handling configuration attributes

Similar to assign_vips() used by a peer assigning virtual IPs to the other peer,
the handle_vips() hook gets invoked on a peers after receiving attributes. On
release of the same attributes the hook gets invoked again.

This is useful to inspect handled attributes, as the ike_updown() hook is
invoked after authentication, when attributes have not been handled yet.

src/libcharon/bus/bus.c

@@ -879,6 +879,33 @@ METHOD(bus_t, assign_vips, void,
 	this->mutex->unlock(this->mutex);
 }
 
+METHOD(bus_t, handle_vips, void,
+	private_bus_t *this, ike_sa_t *ike_sa, bool handle)
+{
+	enumerator_t *enumerator;
+	entry_t *entry;
+	bool keep;
+
+	this->mutex->lock(this->mutex);
+	enumerator = this->listeners->create_enumerator(this->listeners);
+	while (enumerator->enumerate(enumerator, &entry))
+	{
+		if (entry->calling || !entry->listener->handle_vips)
+		{
+			continue;
+		}
+		entry->calling++;
+		keep = entry->listener->handle_vips(entry->listener, ike_sa, handle);
+		entry->calling--;
+		if (!keep)
+		{
+			unregister_listener(this, entry, enumerator);
+		}
+	}
+	enumerator->destroy(enumerator);
+	this->mutex->unlock(this->mutex);
+}
+
 /**
  * Credential manager hook function to forward bus alerts
  */
@@ -955,6 +982,7 @@ bus_t *bus_create()
 			.authorize = _authorize,
 			.narrow = _narrow,
 			.assign_vips = _assign_vips,
+			.handle_vips = _handle_vips,
 			.destroy = _destroy,
 		},
 		.listeners = linked_list_create(),

src/libcharon/bus/bus.h

@@ -411,6 +411,14 @@ struct bus_t {
 	 */
 	void (*assign_vips)(bus_t *this, ike_sa_t *ike_sa, bool assign);
 
+	/**
+	 * Virtual IP handler hook.
+	 *
+	 * @param ike_sa	IKE_SA the VIPs/attributes got handled on
+	 * @param assign	TRUE after installing attributes, FALSE on release
+	 */
+	void (*handle_vips)(bus_t *this, ike_sa_t *ike_sa, bool handle);
+
 	/**
 	 * Destroy the event bus.
 	 */

src/libcharon/bus/listeners/listener.h

@@ -203,6 +203,18 @@ struct listener_t {
 	 */
 	bool (*assign_vips)(listener_t *this, ike_sa_t *ike_sa, bool assign);
 
+	/**
+	 * Virtual IP and configuration attribute handler hook.
+	 *
+	 * This hook gets invoked after virtual IP and other configuration
+	 * attributes just got installed or are about to get uninstalled on a peer
+	 * receiving them.
+	 *
+	 * @param ike_sa	IKE_SA the VIPs/attributes are handled on
+	 * @param handle	TRUE if handled by IKE_SA, FALSE on release
+	 * @return			TRUE to stay registered, FALSE to unregister
+	 */
+	bool (*handle_vips)(listener_t *this, ike_sa_t *ike_sa, bool handle);
 };
 
 #endif /** LISTENER_H_ @}*/

src/libcharon/sa/ike_sa.c

@@ -2168,6 +2168,7 @@ METHOD(ike_sa_t, destroy, void,
 	}
 
 	/* remove attributes first, as we pass the IKE_SA to the handler */
+	charon->bus->handle_vips(charon->bus, &this->public, FALSE);
 	while (array_remove(this->attributes, ARRAY_TAIL, &entry))
 	{
 		if (entry.handler)

src/libcharon/sa/ikev1/tasks/mode_config.c

@@ -441,6 +441,8 @@ static void install_vips(private_mode_config_t *this)
 		}
 	}
 	enumerator->destroy(enumerator);
+
+	charon->bus->handle_vips(charon->bus, this->ike_sa, TRUE);
 }
 
 METHOD(task_t, process_r, status_t,

src/libcharon/sa/ikev2/tasks/ike_config.c

@@ -446,6 +446,8 @@ METHOD(task_t, process_i, status_t,
 			}
 		}
 		enumerator->destroy(enumerator);
+
+		charon->bus->handle_vips(charon->bus, this->ike_sa, TRUE);
 		return SUCCESS;
 	}
 	return NEED_MORE;