res_pjsip: Fix infinite recursion when loading transports from realtime

Attempting to load a transport from realtime was forcing asterisk into an
infinite recursion loop.  The first thing transport_apply did was to do a
sorcery retrieve by id for an existing transport of the same name. For files,
this just returns the previous object from res_sorcery_config's internal
container, if any.  For realtime, the res_sourcery_realtime driver looks in the
database and finds the existing row but now it has to rehydrate it into a
sorcery object which means calling... transport_apply.  And so it goes.

The main issue with loading from realtime (apart from the loop) was that
transport stores structures and pointers directly in the ast_sip_transport
structure instead of the separate ast_transport_state structure.  This patch
separates those items into the ast_sip_transport_state structure.  The pattern
is roughly the same as res_pjsip_outbound_registration.

Although all current usages of ast_sip_transport and ast_sip_transport_state
were modified to use the new ast_sip_get_transport_state API, the original
items are left in ast_sip_transport and kept updated to maintain ABI
compatability for third-party modules.  They are marked as deprecated and
noted that they're now in ast_sip_transport_state.

ASTERISK-25606 #close
Reported-by: Martin Moučka

Change-Id: Ic7a836ea8e786e8def51fe3f8cce855ea54f5f19

1 files changed, 9 insertions, 11 deletions

diff --git a/res/res_pjsip_multihomed.c b/res/res_pjsip_multihomed.c
index 437a1cbe9..745bc37ea 100644
--- a/res/res_pjsip_multihomed.c
+++ b/res/res_pjsip_multihomed.c
@@ -33,30 +33,28 @@
 /*! \brief Helper function which returns a UDP transport bound to the given address and port */
 static pjsip_transport *multihomed_get_udp_transport(pj_str_t *address, int port)
 {
-	struct ao2_container *transports = ast_sorcery_retrieve_by_fields(ast_sip_get_sorcery(), "transport",
-		AST_RETRIEVE_FLAG_MULTIPLE | AST_RETRIEVE_FLAG_ALL, NULL);
-	struct ast_sip_transport *transport;
+	struct ao2_container *transport_states = ast_sip_get_transport_states();
+	struct ast_sip_transport_state *transport_state;
 	struct ao2_iterator iter;
 	pjsip_transport *sip_transport = NULL;
 
-	if (!transports) {
+	if (!transport_states) {
 		return NULL;
 	}
 
-	for (iter = ao2_iterator_init(transports, 0); (transport = ao2_iterator_next(&iter)); ao2_ref(transport, -1)) {
-		if ((transport->type != AST_TRANSPORT_UDP) ||
-			(pj_strcmp(&transport->state->transport->local_name.host, address)) ||
-			(transport->state->transport->local_name.port != port)) {
+	for (iter = ao2_iterator_init(transport_states, 0); (transport_state = ao2_iterator_next(&iter)); ao2_ref(transport_state, -1)) {
+		if (transport_state && ((transport_state->type != AST_TRANSPORT_UDP) ||
+			(pj_strcmp(&transport_state->transport->local_name.host, address)) ||
+			(transport_state->transport->local_name.port != port))) {
 			continue;
 		}
 
-		sip_transport = transport->state->transport;
-		ao2_ref(transport, -1);
+		sip_transport = transport_state->transport;
 		break;
 	}
 	ao2_iterator_destroy(&iter);
 
-	ao2_ref(transports, -1);
+	ao2_ref(transport_states, -1);
 
 	return sip_transport;
 }