child-rekey: Add method to check for the redundant SA created in a collision

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

@@ -1,7 +1,8 @@
 /*
+ * Copyright (C) 2009-2016 Tobias Brunner
  * Copyright (C) 2005-2007 Martin Willi
  * Copyright (C) 2005 Jan Hutter
- * Hochschule fuer Technik Rapperswil
+ * HSR Hochschule fuer Technik Rapperswil
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
@@ -434,6 +435,18 @@ METHOD(task_t, get_type, task_type_t,
 	return TASK_CHILD_REKEY;
 }
 
+METHOD(child_rekey_t, is_redundant, bool,
+	private_child_rekey_t *this, child_sa_t *child)
+{
+	if (this->collision &&
+		this->collision->get_type(this->collision) == TASK_CHILD_REKEY)
+	{
+		private_child_rekey_t *rekey = (private_child_rekey_t*)this->collision;
+		return child == rekey->child_create->get_child(rekey->child_create);
+	}
+	return FALSE;
+}
+
 METHOD(child_rekey_t, collide, void,
 	private_child_rekey_t *this, task_t *other)
 {
@@ -452,19 +465,11 @@ METHOD(child_rekey_t, collide, void,
 	else if (other->get_type(other) == TASK_CHILD_DELETE)
 	{
 		child_delete_t *del = (child_delete_t*)other;
-		if (this->collision &&
+		if (is_redundant(this, del->get_child(del)))
-			this->collision->get_type(this->collision) == TASK_CHILD_REKEY)
 		{
-			private_child_rekey_t *rekey;
+			this->other_child_destroyed = TRUE;
-
+			other->destroy(other);
-			rekey = (private_child_rekey_t*)this->collision;
+			return;
-			if (del->get_child(del) == rekey->child_create->get_child(rekey->child_create))
-			{
-				/* peer deletes redundant child created in collision */
-				this->other_child_destroyed = TRUE;
-				other->destroy(other);
-				return;
-			}
 		}
 		if (del->get_child(del) != this->child_sa)
 		{
@@ -475,7 +480,7 @@ METHOD(child_rekey_t, collide, void,
 	}
 	else
 	{
-		/* any other task is not critical for collisisions, ignore */
+		/* any other task is not critical for collisions, ignore */
 		other->destroy(other);
 		return;
 	}
@@ -532,6 +537,7 @@ child_rekey_t *child_rekey_create(ike_sa_t *ike_sa, protocol_id_t protocol,
 				.migrate = _migrate,
 				.destroy = _destroy,
 			},
+			.is_redundant = _is_redundant,
 			.collide = _collide,
 		},
 		.ike_sa = ike_sa,

src/libcharon/sa/ikev2/tasks/child_rekey.h

@@ -1,6 +1,7 @@
 /*
+ * Copyright (C) 2016 Tobias Brunner
  * Copyright (C) 2007 Martin Willi
- * Hochschule fuer Technik Rapperswil
+ * HSR Hochschule fuer Technik Rapperswil
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
@@ -39,13 +40,25 @@ struct child_rekey_t {
 	task_t task;
 
 	/**
-	 * Register a rekeying task which collides with this one
+	 * Check if the given SA is the redundant CHILD_SA created during a rekey
+	 * collision.
+	 *
+	 * This is called if the other peer deletes the redundant SA before we were
+	 * able to handle the CREATE_CHILD_SA response.
+	 *
+	 * @param child		CHILD_SA to check
+	 * @return			TRUE if the SA is the redundant CHILD_SA
+	 */
+	bool (*is_redundant)(child_rekey_t *this, child_sa_t *child);
+
+	/**
+	 * Register a rekeying/delete task which collides with this one
 	 *
 	 * If two peers initiate rekeying at the same time, the collision must
 	 * be handled gracefully. The task manager is aware of what exchanges
-	 * are going on and notifies the outgoing task by passing the incoming.
+	 * are going on and notifies the active task by passing the passive.
 	 *
-	 * @param other		incoming task
+	 * @param other		passive task (adopted)
 	 */
 	void (*collide)(child_rekey_t* this, task_t *other);
 };