Add ike_reestablish() event that is triggered when an IKE_SA is reestablished

This is particularly useful during reauthentication to get the new
IKE_SA.

src/libcharon/bus/bus.c

@@ -659,6 +659,33 @@ METHOD(bus_t, ike_rekey, void,
 	this->mutex->unlock(this->mutex);
 }
 
+METHOD(bus_t, ike_reestablish, void,
+	private_bus_t *this, ike_sa_t *old, ike_sa_t *new)
+{
+	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->ike_reestablish)
+		{
+			continue;
+		}
+		entry->calling++;
+		keep = entry->listener->ike_reestablish(entry->listener, old, new);
+		entry->calling--;
+		if (!keep)
+		{
+			unregister_listener(this, entry, enumerator);
+		}
+	}
+	enumerator->destroy(enumerator);
+	this->mutex->unlock(this->mutex);
+}
+
 METHOD(bus_t, authorize, bool,
 	private_bus_t *this, bool final)
 {
@@ -770,6 +797,7 @@ bus_t *bus_create()
 			.child_keys = _child_keys,
 			.ike_updown = _ike_updown,
 			.ike_rekey = _ike_rekey,
+			.ike_reestablish = _ike_reestablish,
 			.child_updown = _child_updown,
 			.child_rekey = _child_rekey,
 			.authorize = _authorize,

src/libcharon/bus/bus.h

@@ -317,6 +317,14 @@ struct bus_t {
 	 */
 	void (*ike_rekey)(bus_t *this, ike_sa_t *old, ike_sa_t *new);
 
+	/**
+	 * IKE_SA reestablishing hook.
+	 *
+	 * @param old		reestablished and obsolete IKE_SA
+	 * @param new		new IKE_SA replacing old
+	 */
+	void (*ike_reestablish)(bus_t *this, ike_sa_t *old, ike_sa_t *new);
+
 	/**
 	 * CHILD_SA up/down hook.
 	 *

src/libcharon/bus/listeners/listener.h

@@ -126,6 +126,18 @@ struct listener_t {
 	 */
 	bool (*ike_rekey)(listener_t *this, ike_sa_t *old, ike_sa_t *new);
 
+	/**
+	 * Hook called when an initiator reestablishes an IKE_SA.
+	 *
+	 * This is invoked right before the new IKE_SA is checked in after
+	 * initiating it.  It is not invoked on the responder.
+	 *
+	 * @param old		IKE_SA getting reestablished (is destroyed)
+	 * @param new		new IKE_SA replacing old (gets established)
+	 * @return			TRUE to stay registered, FALSE to unregister
+	 */
+	bool (*ike_reestablish)(listener_t *this, ike_sa_t *old, ike_sa_t *new);
+
 	/**
 	 * Hook called when a CHILD_SA gets up or down.
 	 *

src/libcharon/sa/ike_sa.c

@@ -1659,6 +1659,7 @@ METHOD(ike_sa_t, reestablish, status_t,
 	}
 	else
 	{
+		charon->bus->ike_reestablish(charon->bus, &this->public, new);
 		charon->ike_sa_manager->checkin(charon->ike_sa_manager, new);
 		status = SUCCESS;
 	}