Raise an alert if IKE SA is kept

This alert is raised when the establishment of a child SA fails but the
IKE SA is kept.

src/libcharon/bus/bus.h

@@ -124,6 +124,8 @@ enum alert_t {
 	ALERT_UNIQUE_REPLACE,
 	/** IKE_SA deleted because of "keep" unique policy, no arguement */
 	ALERT_UNIQUE_KEEP,
+	/** IKE_SA kept on failed child SA establishment, no argument */
+	ALERT_KEEP_ON_CHILD_SA_FAILURE,
 	/** allocating virtual IP failed, linked_list_t of host_t requested */
 	ALERT_VIP_FAILURE,
 	/** an authorize() hook failed, no argument */

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

@@ -989,6 +989,7 @@ static void handle_child_sa_failure(private_child_create_t *this,
 	else
 	{
 		DBG1(DBG_IKE, "failed to establish CHILD_SA, keeping IKE_SA");
+		charon->bus->alert(charon->bus, ALERT_KEEP_ON_CHILD_SA_FAILURE);
 	}
 }