NS / GB Proxy: Add Signal in case Tns-Alive expires too often

The Gb Proxy can then restart the RESET procedure.

openbsc/include/openbsc/signal.h

@@ -149,6 +149,7 @@ enum signal_ns {
 	S_NS_RESET,
 	S_NS_BLOCK,
 	S_NS_UNBLOCK,
+	S_NS_ALIVE_EXP,	/* Tns-alive expired more than N times */
 };
 
 struct ns_signal_data {

openbsc/src/gprs/gb_proxy.c

@@ -488,6 +488,13 @@ int gbprox_signal(unsigned int subsys, unsigned int signal,
 		nsvc->remote_end_is_sgsn = 1;
 	}
 
+	if (signal == S_NS_ALIVE_EXP && nsvc->remote_end_is_sgsn) {
+		LOGP(DGPRS, LOGL_NOTICE, "Tns alive expired too often, "
+			"re-starting RESET procedure\n");
+		nsip_connect(nsvc->nsi, &nsvc->ip.bts_addr, nsvc->nsei,
+			     nsvc->nsvci);
+	}
+
 	/* We currently only care about signals from the SGSN */
 	if (!nsvc->remote_end_is_sgsn)
 		return 0;

openbsc/src/gprs/gprs_ns.c

@@ -362,6 +362,7 @@ static void gprs_ns_timer_cb(void *data)
 				"NSEI=%u Tns-alive expired more then "
 				"%u times, blocking NS-VC\n", nsvc->nsei,
 				NS_ALIVE_RETRIES);
+			ns_dispatch_signal(nsvc, S_NS_ALIVE_EXP, 0);
 			ns_dispatch_signal(nsvc, S_NS_BLOCK, NS_CAUSE_NSVC_BLOCKED);
 			return;
 		}