TT#86102 remove aggressive endpoint learning heuristics

The previous approach causes problems during re-invites with updated
port (or address) information. The UA might delay actually using the new
endpoint until after the answer is seen, in which case rtpengine would
erroneously immediately latch on to the old endpoint. We need to
reinstate the endpoint learning delay in all cases, and make sure
previously learned endpoints are forgotten whenever a new signal is
seen.

Change-Id: If42ed13c43710616c02cdf018b36a4543d7f6bfe
(cherry picked from commit 112e57f9fe)

daemon/media_socket.c

@@ -1646,6 +1646,12 @@ static int media_packet_address_check(struct packet_handler_ctx *phc)
 			&& phc->mp.stream->advertised_endpoint.address.family
 			&& phc->mp.stream->advertised_endpoint.port)
 	{
+		// check if we need to reset our learned endpoints
+		if (memcmp(&rtpe_now, &phc->mp.stream->ep_detect_signal, sizeof(rtpe_now))) {
+			memset(&phc->mp.stream->detected_endpoints, 0, sizeof(phc->mp.stream->detected_endpoints));
+			phc->mp.stream->ep_detect_signal = rtpe_now;
+		}
+
 		// possible endpoints that can be detected in order of preference:
 		// 0: endpoint that matches the address advertised in the SDP
 		// 1: endpoint with the same address but different port
@@ -1664,11 +1670,8 @@ static int media_packet_address_check(struct packet_handler_ctx *phc)
 		// now grab the best matched endpoint
 		for (idx = 0; idx < 4; idx++) {
 			use_endpoint_confirm = &phc->mp.stream->detected_endpoints[idx];
-			if (use_endpoint_confirm->address.family) {
-				if (idx == 0) // doesn't get any better than this
-					goto confirm_now;
+			if (use_endpoint_confirm->address.family)
 				break;
-			}
 		}
 	}
 

include/call.h

@@ -266,6 +266,7 @@ struct packet_stream {
 	const struct streamhandler *handler;	/* LOCK: in_lock */
 	struct endpoint		endpoint;	/* LOCK: out_lock */
 	struct endpoint		detected_endpoints[4];	/* LOCK: out_lock */
+	struct timeval		ep_detect_signal; /* LOCK: out_lock */
 	struct endpoint		advertised_endpoint; /* RO */
 	struct crypto_context	crypto;		/* OUT direction, LOCK: out_lock */
 	struct ssrc_ctx		*ssrc_in,	/* LOCK: in_lock */ // XXX eliminate these