peer-cfg: Store mediated_by as name and not peer-cfg reference

This way updates to the mediation config are respected and the order in
which configs are configured/loaded does not matter.

The SQL plugin currently maintains the strong relationship between
mediated and mediation connection (we could theoretically change that to a
string too).

src/libcharon/plugins/medcli/medcli_config.c

@@ -23,6 +23,11 @@
 
 typedef struct private_medcli_config_t private_medcli_config_t;
 
+/**
+ * Name of the mediation connection
+ */
+#define MEDIATION_CONN_NAME "medcli-mediation"
+
 /**
  * Private data of an medcli_config_t object
  */
@@ -72,36 +77,19 @@ static traffic_selector_t *ts_from_string(char *str)
 	return traffic_selector_create_dynamic(0, 0, 65535);
 }
 
-METHOD(backend_t, get_peer_cfg_by_name, peer_cfg_t*,
-	private_medcli_config_t *this, char *name)
+/**
+ * Build a mediation config
+ */
+static peer_cfg_t *build_mediation_config(private_medcli_config_t *this,
+										  peer_cfg_create_t *defaults)
 {
 	enumerator_t *e;
-	peer_cfg_t *peer_cfg, *med_cfg;
 	auth_cfg_t *auth;
 	ike_cfg_t *ike_cfg;
-	child_cfg_t *child_cfg;
+	peer_cfg_t *med_cfg;
+	peer_cfg_create_t peer = *defaults;
 	chunk_t me, other;
-	char *address, *local_net, *remote_net;
-	peer_cfg_create_t peer = {
-		.cert_policy = CERT_NEVER_SEND,
-		.unique = UNIQUE_REPLACE,
-		.keyingtries = 1,
-		.rekey_time = this->rekey * 60,
-		.jitter_time = this->rekey * 5,
-		.over_time = this->rekey * 3,
-		.dpd = this->dpd,
-		.mediation = TRUE,
-	};
-	child_cfg_create_t child = {
-		.lifetime = {
-			.time = {
-				.life = this->rekey * 60 + this->rekey,
-				.rekey = this->rekey,
-				.jitter = this->rekey
-			},
-		},
-		.mode = MODE_TUNNEL,
-	};
+	char *address;
 
 	/* query mediation server config:
 	 * - build ike_cfg/peer_cfg for mediation connection on-the-fly
@@ -120,7 +108,9 @@ METHOD(backend_t, get_peer_cfg_by_name, peer_cfg_t*,
 							 address, IKEV2_UDP_PORT, FRAGMENTATION_NO, 0);
 	ike_cfg->add_proposal(ike_cfg, proposal_create_default(PROTO_IKE));
 	ike_cfg->add_proposal(ike_cfg, proposal_create_default_aead(PROTO_IKE));
-	med_cfg = peer_cfg_create("mediation", ike_cfg, &peer);
+
+	peer.mediation = TRUE;
+	med_cfg = peer_cfg_create(MEDIATION_CONN_NAME, ike_cfg, &peer);
 	e->destroy(e);
 
 	auth = auth_cfg_create();
@@ -133,6 +123,42 @@ METHOD(backend_t, get_peer_cfg_by_name, peer_cfg_t*,
 	auth->add(auth, AUTH_RULE_IDENTITY,
 			  identification_create_from_encoding(ID_KEY_ID, other));
 	med_cfg->add_auth_cfg(med_cfg, auth, FALSE);
+	return med_cfg;
+}
+
+METHOD(backend_t, get_peer_cfg_by_name, peer_cfg_t*,
+	private_medcli_config_t *this, char *name)
+{
+	enumerator_t *e;
+	auth_cfg_t *auth;
+	peer_cfg_t *peer_cfg;
+	child_cfg_t *child_cfg;
+	chunk_t me, other;
+	char *local_net, *remote_net;
+	peer_cfg_create_t peer = {
+		.cert_policy = CERT_NEVER_SEND,
+		.unique = UNIQUE_REPLACE,
+		.keyingtries = 1,
+		.rekey_time = this->rekey * 60,
+		.jitter_time = this->rekey * 5,
+		.over_time = this->rekey * 3,
+		.dpd = this->dpd,
+	};
+	child_cfg_create_t child = {
+		.lifetime = {
+			.time = {
+				.life = this->rekey * 60 + this->rekey,
+				.rekey = this->rekey,
+				.jitter = this->rekey
+			},
+		},
+		.mode = MODE_TUNNEL,
+	};
+
+	if (streq(name, "medcli-mediation"))
+	{
+		return build_mediation_config(this, &peer);
+	}
 
 	/* query mediated config:
 	 * - use any-any ike_cfg
@@ -150,8 +176,7 @@ METHOD(backend_t, get_peer_cfg_by_name, peer_cfg_t*,
 		DESTROY_IF(e);
 		return NULL;
 	}
-	peer.mediation = FALSE;
-	peer.mediated_by = med_cfg;
+	peer.mediated_by = MEDIATION_CONN_NAME;
 	peer.peer_id = identification_create_from_encoding(ID_KEY_ID, other);
 	peer_cfg = peer_cfg_create(name, this->ike->get_ref(this->ike), &peer);
 

src/libcharon/plugins/sql/sql_config.c

@@ -381,12 +381,14 @@ static peer_cfg_t *build_peer_cfg(private_sql_config_t *this, enumerator_t *e,
 		ike = get_ike_cfg_by_id(this, ike_cfg);
 
 #ifdef ME
-		mediated_cfg = mediated_by ? get_peer_cfg_by_id(this, mediated_by) : NULL;
+		mediated_cfg = mediated_by ? get_peer_cfg_by_id(this, mediated_by)
+								   : NULL;
 		if (p_type)
 		{
 			peer_id = identification_create_from_encoding(p_type, p_data);
 		}
-#endif
+#endif /* ME */
+
 		if (virtual)
 		{
 			vip = host_create_from_string(virtual, 0);
@@ -405,7 +407,8 @@ static peer_cfg_t *build_peer_cfg(private_sql_config_t *this, enumerator_t *e,
 				.dpd = dpd_delay,
 #ifdef ME
 				.mediation = mediation,
-				.mediated_by = mediated_cfg,
+				.mediated_by = mediated_cfg ?
+									mediated_cfg->get_name(mediated_cfg) : NULL,
 				.peer_id = peer_id,
 #endif /* ME */
 			};
@@ -443,6 +446,7 @@ static peer_cfg_t *build_peer_cfg(private_sql_config_t *this, enumerator_t *e,
 			}
 			peer_cfg->add_auth_cfg(peer_cfg, auth, FALSE);
 			add_child_cfgs(this, peer_cfg, id);
+			DESTROY_IF(mediated_cfg);
 			return peer_cfg;
 		}
 		DESTROY_IF(ike);

src/libcharon/plugins/stroke/stroke_config.c

@@ -642,28 +642,9 @@ static peer_cfg_t *build_peer_cfg(private_stroke_config_t *this,
 		/* force unique connections for mediation connections */
 		msg->add_conn.unique = 1;
 	}
-
-	if (msg->add_conn.ikeme.mediated_by)
+	else if (msg->add_conn.ikeme.mediated_by)
 	{
-		peer_cfg_t *mediated_by;
-
-		mediated_by = charon->backends->get_peer_cfg_by_name(
-							charon->backends, msg->add_conn.ikeme.mediated_by);
-		if (!mediated_by)
-		{
-			DBG1(DBG_CFG, "mediation connection '%s' not found, aborting",
-				 msg->add_conn.ikeme.mediated_by);
-			return NULL;
-		}
-		if (!mediated_by->is_mediation(mediated_by))
-		{
-			DBG1(DBG_CFG, "connection '%s' as referred to by '%s' is "
-				 "no mediation connection, aborting",
-				 msg->add_conn.ikeme.mediated_by, msg->add_conn.name);
-			mediated_by->destroy(mediated_by);
-			return NULL;
-		}
-		peer.mediated_by = mediated_by;
+		peer.mediated_by = msg->add_conn.ikeme.mediated_by;
 		if (msg->add_conn.ikeme.peerid)
 		{
 			peer.peer_id = identification_create_from_string(