As responder, enforce the same configuration while rekeying CHILD_SAs

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

@@ -935,7 +935,7 @@ METHOD(task_t, build_r, status_t,
 	}
 
 	peer_cfg = this->ike_sa->get_peer_cfg(this->ike_sa);
-	if (peer_cfg && this->tsi && this->tsr)
+	if (!this->config && peer_cfg && this->tsi && this->tsr)
 	{
 		host_t *me, *other;
 
@@ -1196,6 +1196,13 @@ METHOD(child_create_t, get_child, child_sa_t*,
 	return this->child_sa;
 }
 
+METHOD(child_create_t, set_config, void,
+	private_child_create_t *this, child_cfg_t *cfg)
+{
+	DESTROY_IF(this->config);
+	this->config = cfg;
+}
+
 METHOD(child_create_t, get_lower_nonce, chunk_t,
 	private_child_create_t *this)
 {
@@ -1295,6 +1302,7 @@ child_create_t *child_create_create(ike_sa_t *ike_sa,
 	INIT(this,
 		.public = {
 			.get_child = _get_child,
+			.set_config = _set_config,
 			.get_lower_nonce = _get_lower_nonce,
 			.use_reqid = _use_reqid,
 			.task = {

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

@@ -64,6 +64,13 @@ struct child_create_t {
 	 * @return			child_sa
 	 */
 	child_sa_t* (*get_child) (child_create_t *this);
+
+	/**
+	 * Enforce a specific CHILD_SA config as responder.
+	 *
+	 * @param cfg		configuration to enforce, reference gets owned
+	 */
+	void (*set_config)(child_create_t *this, child_cfg_t *cfg);
 };
 
 /**

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

@@ -187,6 +187,7 @@ METHOD(task_t, process_r, status_t,
 METHOD(task_t, build_r, status_t,
 	private_child_rekey_t *this, message_t *message)
 {
+	child_cfg_t *config;
 	u_int32_t reqid;
 
 	if (this->child_sa == NULL ||
@@ -200,6 +201,8 @@ METHOD(task_t, build_r, status_t,
 	/* let the CHILD_CREATE task build the response */
 	reqid = this->child_sa->get_reqid(this->child_sa);
 	this->child_create->use_reqid(this->child_create, reqid);
+	config = this->child_sa->get_config(this->child_sa);
+	this->child_create->set_config(this->child_create, config->get_ref(config));
 	this->child_create->task.build(&this->child_create->task, message);
 
 	if (message->get_payload(message, SECURITY_ASSOCIATION) == NULL)