Changes transport option in sip.conf so that using multiple instances doesn't stack.

Prior to this patch, Using "transport=" multiple times would cause them to add to one
another like allow/deny. This patch changes that behavior to simply use the transport
option specified last. Also, if no transport option is applied now, the default will
automatically be UDP.

(closes ASTERISK-19352)
Reported by: jamicque
Patches:
	asterisk-19352-transport-warning-message-v1.patch uploaded by Michael L. Young (license 5026)
	issueA19352_no_transport_is_udp.patch uploaded by Walter Doekes (license 5674)
Review: https://reviewboard.asterisk.org/r/1745/diff/#index_header



git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@357266 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -27268,10 +27268,11 @@ static struct sip_peer *build_peer(const char *name, struct ast_variable *v, str
 			if (handle_t38_options(&peerflags[0], &mask[0], v, &peer->t38_maxdatagram)) {
 				continue;
 			}
-			if (!strcasecmp(v->name, "transport") && !ast_strlen_zero(v->value)) {
+			if (!strcasecmp(v->name, "transport")) {
 				char *val = ast_strdupa(v->value);
 				char *trans;
 
+				peer->transports = peer->default_outbound_transport = 0;
 				while ((trans = strsep(&val, ","))) {
 					trans = ast_skip_blanks(trans);
 
@@ -27282,7 +27283,7 @@ static struct sip_peer *build_peer(const char *name, struct ast_variable *v, str
 					} else if (default_tls_cfg.enabled && !strncasecmp(trans, "tls", 3)) {
 						peer->transports |= SIP_TRANSPORT_TLS;
 					} else if (!strncasecmp(trans, "tcp", 3) || !strncasecmp(trans, "tls", 3)) {
-						ast_log(LOG_WARNING, "'%.3s' is not a valid transport type when %.3senabled=no. If no other is specified, the defaults from general will be used.\n", trans, trans);
+						ast_log(LOG_WARNING, "'%.3s' is not a valid transport type when %.3senable=no. If no other is specified, the defaults from general will be used.\n", trans, trans);
 					} else {
 						ast_log(LOG_NOTICE, "'%s' is not a valid transport type. if no other is specified, the defaults from general will be used.\n", trans);
 					}
@@ -28003,8 +28004,8 @@ static int reload_config(enum channelreloadreason reason)
 	memset(&default_prefs, 0 , sizeof(default_prefs));
 	memset(&sip_cfg.outboundproxy, 0, sizeof(struct sip_proxy));
 	sip_cfg.outboundproxy.force = FALSE;		/*!< Don't force proxy usage, use route: headers */
-	default_transports = 0;				/*!< Reset default transport to zero here, default value later on */
-	default_primary_transport = 0;			/*!< Reset default primary transport to zero here, default value later on */
+	default_transports = SIP_TRANSPORT_UDP;
+	default_primary_transport = SIP_TRANSPORT_UDP;
 	ourport_tcp = STANDARD_SIP_PORT;
 	ourport_tls = STANDARD_TLS_PORT;
 	externtcpport = STANDARD_SIP_PORT;
@@ -28190,10 +28191,11 @@ static int reload_config(enum channelreloadreason reason)
 			timerb_set = 1;
 		} else if (!strcasecmp(v->name, "t1min")) {
 			global_t1min = atoi(v->value);
-		} else if (!strcasecmp(v->name, "transport") && !ast_strlen_zero(v->value)) {
+		} else if (!strcasecmp(v->name, "transport")) {
 			char *val = ast_strdupa(v->value);
 			char *trans;
 
+			default_transports = default_primary_transport = 0;
 			while ((trans = strsep(&val, ","))) {
 				trans = ast_skip_blanks(trans);