Enable round robin for default interface

README.md

@@ -674,6 +674,10 @@ no alternatives would be used. When IPv6 is needed as a primary address, either
 `pub:3` might be selected. If at any given time not enough ports are available on any interface,
 it will not be selected by the round-robin algorithm.
 
+It is possible to use the round-robin algorithm even if the `direction` is not given. If the first
+given interface has the `BASE:SUFFIX` format then the round-robin algorithm is used and will select
+interfaces with the same `BASE` name.
+
 If you're not using the NG protocol but rather the legacy UDP protocol used by the *rtpproxy* module,
 the interfaces must be named `internal` and `external` corresponding to the `i` and `e` flags if you
 wish to use network bridging in this mode.

daemon/media_socket.c

@@ -378,6 +378,7 @@ done:
 // 'fam' may only be NULL if 'name' is also NULL
 struct logical_intf *get_logical_interface(const str *name, sockfamily_t *fam, int num_ports) {
 	struct logical_intf *log = NULL;
+	int rr_use_default_intf = 0;
 
 	__C_DBG("Get logical interface for %d ports", num_ports);
 
@@ -397,14 +398,26 @@ struct logical_intf *get_logical_interface(const str *name, sockfamily_t *fam, i
 got_some:
 			;
 		}
-
-		return q->head ? q->head->data : NULL;
+		if (!q->head)
+			return NULL;
+
+		log = q->head->data;
+		// if interface is in the form foo:bar then use round-robin
+		if (!fam || log->name.len == log->name_base.len)
+			return log;
+		else
+			rr_use_default_intf = 1;
 	}
 
 	// check if round-robin is desired
 	struct logical_intf key;
-	key.name = *name;
+
+	if (rr_use_default_intf)
+		key.name = log->name_base;
+	else
+		key.name = *name;
 	key.preferred_family = fam;
+
 	struct intf_rr *rr = g_hash_table_lookup(__logical_intf_name_family_rr_hash, &key);
 	if (!rr)
 		return __get_logical_interface(name, fam);
@@ -522,7 +535,9 @@ static void __interface_append(struct intf_config *ifa, sockfamily_t *fam) {
 
 	if (!lif) {
 		lif = g_slice_alloc0(sizeof(*lif));
+		g_queue_init(&lif->list);
 		lif->name = ifa->name;
+		lif->name_base = ifa->name_base;
 		lif->preferred_family = fam;
 		lif->addr_hash = g_hash_table_new(__addr_type_hash, __addr_type_eq);
 		lif->rr_specs = g_hash_table_new(str_hash, str_equal);

daemon/media_socket.h

@@ -23,6 +23,7 @@ struct logical_intf {
 	GQueue				list; /* struct local_intf */
 	GHashTable			*addr_hash; // addr + type -> struct local_intf XXX obsolete?
 	GHashTable			*rr_specs;
+	str				name_base; // if name is "foo:bar", this is "foo"
 };
 struct port_pool {
 	BIT_ARRAY_DECLARE(ports_used, 0x10000);