Fix for Q.921 not always recovering

libs/freetdm/src/ftmod/ftmod_sangoma_isdn/ftmod_sangoma_isdn_stack_out.c

@@ -475,8 +475,16 @@ void sngisdn_snd_restart(ftdm_channel_t *ftdmchan)
 void sngisdn_snd_data(ftdm_channel_t *dchan, uint8_t *data, ftdm_size_t len)
 {
 	sng_l1_frame_t l1_frame;
+	ftdm_alarm_flag_t alarmbits = 0;
 	sngisdn_span_data_t *signal_data = (sngisdn_span_data_t*) dchan->span->signal_data;
 
+	ftdm_channel_get_alarms(dchan, &alarmbits);
+
+	if (alarmbits) {
+		ftdm_log_chan_msg(dchan, FTDM_LOG_WARNING, "Dropping incoming data due to L1 alarm\n");
+		return;
+	}
+
 	if (len > sizeof(l1_frame.data)) {
 		ftdm_log_chan(dchan, FTDM_LOG_ERROR, "Received frame of %"FTDM_SIZE_FMT" bytes, exceeding max size of %"FTDM_SIZE_FMT" bytes\n", 
 				len, sizeof(l1_frame.data));
@@ -548,9 +556,11 @@ void sngisdn_snd_event(sngisdn_span_data_t *signal_data, ftdm_oob_event_t event)
 		case FTDM_OOB_ALARM_CLEAR:
 			l1_event.type = SNG_L1EVENT_ALARM_OFF;
 			sng_isdn_event_ind(signal_data->link_id, &l1_event);
-			
-			ftdm_sched_timer(signal_data->sched, "delayed_dl_req", 8000, sngisdn_delayed_dl_req, (void*) signal_data, NULL);
-			signal_data->dl_request_pending = 1;
+
+			if (!signal_data->dl_request_pending) {
+				signal_data->dl_request_pending = 1;
+				ftdm_sched_timer(signal_data->sched, "delayed_dl_req", 8000, sngisdn_delayed_dl_req, (void*) signal_data, NULL);
+			}
 			break;
 		case FTDM_OOB_ALARM_TRAP:
 			l1_event.type = SNG_L1EVENT_ALARM_ON;

libs/freetdm/src/ftmod/ftmod_sangoma_isdn/ftmod_sangoma_isdn_support.c

@@ -1214,14 +1214,23 @@ void sngisdn_t3_timeout(void *p_sngisdn_info)
 
 void sngisdn_delayed_dl_req(void *p_signal_data)
 {
+	ftdm_signaling_status_t sigstatus = FTDM_SIG_STATE_DOWN;	
 	sngisdn_span_data_t *signal_data = (sngisdn_span_data_t *)p_signal_data;
 	ftdm_span_t *span = signal_data->ftdm_span;
 	
 	if (!signal_data->dl_request_pending) {
 		return;
 	}
-	signal_data->dl_request_pending = 0;
+	
+	ftdm_span_get_sig_status(span, &sigstatus);
+	if (sigstatus == FTDM_SIG_STATE_UP) {
+		signal_data->dl_request_pending = 0;
+		return;
+	}
+
 	sngisdn_snd_dl_req(span->channels[1]);
+	ftdm_sched_timer(signal_data->sched, "delayed_dl_req", 4000, sngisdn_delayed_dl_req, (void*) signal_data, NULL);
+
 	return;
 }