freetdm: Implement SS7 transparent IAM functionality using the event clones queue

libs/freetdm/mod_freetdm/mod_freetdm.c

@@ -1603,6 +1603,23 @@ static switch_call_cause_t channel_outgoing_channel(switch_core_session_t *sessi
 		hunt_data.tech_pvt = tech_pvt;
 		caller_data.priv = &hunt_data;
 
+		if (session
+		 && (var = channel_get_variable(session, var_event, FREETDM_VAR_PREFIX "native_sigbridge")) 
+		 && switch_true(var)
+		 && switch_core_session_compare(*new_session, session)) {
+			char sigbridge_peer[255];
+			private_t *peer_pvt = switch_core_session_get_private(session);
+			switch_channel_t *peer_chan = switch_core_session_get_channel(session);
+			switch_channel_t *our_chan = switch_core_session_get_channel(*new_session);
+			switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, 
+					"Bridging native signaling of channel %s to channel %s\n", 
+					switch_channel_get_name(peer_chan), switch_channel_get_name(our_chan));
+			snprintf(sigbridge_peer, sizeof(sigbridge_peer), "%u:%u", 
+					ftdm_channel_get_span_id(peer_pvt->ftdmchan), ftdm_channel_get_id(peer_pvt->ftdmchan));
+			ftdm_usrmsg_add_var(&usrmsg, "sigbridge_peer", sigbridge_peer);
+		}
+
+
 		if ((status = ftdm_call_place_ex(&caller_data, &hunting, &usrmsg)) != FTDM_SUCCESS) {
 			if (tech_pvt->read_codec.implementation) {
 				switch_core_codec_destroy(&tech_pvt->read_codec);

libs/freetdm/src/ftmod/ftmod_sangoma_ss7/ftmod_sangoma_ss7_main.c

@@ -526,7 +526,7 @@ static void ftdm_sangoma_ss7_process_stack_event (sngss7_event_data_t *sngss7_ev
 		if (sngss7_event->event_id == SNGSS7_CON_IND_EVENT) {
 			/* this is the first event in a call, flush the event queue */
 			while ((event_clone = ftdm_queue_dequeue(sngss7_info->event_queue))) {
-				SS7_WARN("Discarding clone event from past call for circuit = %d!\n", sngss7_event->circuit);
+				SS7_WARN("[CIC:%d]Discarding clone event from past call!\n", sngss7_info->circuit->cic);
 				ftdm_safe_free(event_clone);
 			}
 		}
@@ -1076,6 +1076,19 @@ ftdm_status_t ftdm_sangoma_ss7_process_state_change (ftdm_channel_t * ftdmchan)
 
 		if (ftdm_test_flag (ftdmchan, FTDM_CHANNEL_OPEN)) {
 			ftdm_channel_t *close_chan = ftdmchan;
+
+			/* detach native bridging if needed (only the outbound leg is responsible for that)
+			   Inbound leg was responsible of flushing its queue of events, but peer attach/detach
+			   is left as an outbound leg responsibility
+			 */
+			if (ftdm_test_flag(ftdmchan, FTDM_CHANNEL_OUTBOUND)) {
+				sngss7_chan_data_t *peer_info = sngss7_info->peer_data;
+				sngss7_info->peer_data = NULL;
+				if (peer_info) {
+					peer_info->peer_data = NULL;
+				}
+			}
+
 			/* close the channel */
 			SS7_DEBUG_CHAN(ftdmchan,"FTDM Channel Close %s\n", "");
 			ftdm_channel_close (&close_chan);

libs/freetdm/src/ftmod/ftmod_sangoma_ss7/ftmod_sangoma_ss7_main.h

@@ -486,6 +486,7 @@ typedef struct sngss7_chan_data {
 	sngss7_group_data_t		tx_grs;
 	sngss7_group_data_t		ucic;
 	ftdm_queue_t 			*event_queue;
+	struct sngss7_chan_data *peer_data;
 } sngss7_chan_data_t;
 
 #define SNGSS7_RX_GRS_PENDING (1 << 0)

libs/freetdm/src/ftmod/ftmod_sangoma_ss7/ftmod_sangoma_ss7_out.c

@@ -44,6 +44,7 @@
 /* FUNCTIONS ******************************************************************/
 void ft_to_sngss7_iam (ftdm_channel_t * ftdmchan)
 {	
+	const char *var = NULL;
 	SiConEvnt 			iam;
 	sngss7_chan_data_t	*sngss7_info = ftdmchan->call_data;;
 	
@@ -55,7 +56,59 @@ void ft_to_sngss7_iam (ftdm_channel_t * ftdmchan)
 	
 	memset (&iam, 0x0, sizeof (iam));
 
-	if (sngss7_info->circuit->transparent_iam &&
+	var = ftdm_usrmsg_get_var(ftdmchan->usrmsg, "sigbridge_peer");
+	if (!ftdm_strlen_zero(var)) {
+		ftdm_status_t status = FTDM_SUCCESS;
+		int rc = 0;
+		ftdm_span_t *peer_span = NULL;
+		ftdm_channel_t *peer_chan = NULL;
+		sngss7_chan_data_t *peer_info = NULL;
+		unsigned peer_span_id = 0;
+		unsigned peer_chan_id = 0;
+		rc = sscanf(var, "%u:%u", &peer_span_id, &peer_chan_id);
+		if (rc != 2) {
+			SS7_ERROR_CHAN(ftdmchan, "Failed to parse sigbridge_peer string '%s'\n", var);
+		} else {
+			status = ftdm_span_find(peer_span_id, &peer_span);
+			if (status != FTDM_SUCCESS || !peer_span) {
+				SS7_ERROR_CHAN(ftdmchan, "Failed to find peer span for channel id '%u:%u'\n", peer_span_id, peer_chan_id);
+			} else if (peer_span->signal_type != FTDM_SIGTYPE_SS7) {
+				SS7_ERROR_CHAN(ftdmchan, "Peer channel %d:%d has different signaling type %d'\n", 
+						peer_span_id, peer_chan_id, peer_span->signal_type);
+			} else {
+				if (peer_chan_id > (FTDM_MAX_CHANNELS_SPAN+1) || !(peer_chan = peer_span->channels[peer_chan_id])) {
+					SS7_ERROR_CHAN(ftdmchan, "Invalid peer channel id '%u:%u'\n", peer_span_id, peer_chan_id);
+				} else {
+					sngss7_event_data_t *event_clone = NULL;
+					peer_info = peer_chan->call_data;
+					SS7_INFO_CHAN(ftdmchan,"[CIC:%d]Starting native bridge with peer CIC %d\n", 
+							sngss7_info->circuit->cic, peer_info->circuit->cic);
+					/* make each one of us aware of the native bridge */
+					peer_info->peer_data = sngss7_info;
+					sngss7_info->peer_data = peer_info;
+					/* flush our own queue */
+					while ((event_clone = ftdm_queue_dequeue(sngss7_info->event_queue))) {
+						SS7_WARN("[CIC:%d]Discarding clone event from past call!\n", sngss7_info->circuit->cic);
+						ftdm_safe_free(event_clone);
+					}
+				}
+			}
+		}
+	}
+
+	if (sngss7_info->peer_data) {
+		sngss7_event_data_t *event_clone = ftdm_queue_dequeue(sngss7_info->peer_data->event_queue);
+		/* Retrieve IAM from our peer */
+		if (!event_clone) {
+			SS7_ERROR_CHAN(ftdmchan, "No event clone in peer queue!%s\n", "");
+		} else if (event_clone->event_id != SNGSS7_CON_IND_EVENT) {
+			/* first message in the queue should ALWAYS be an IAM */
+			SS7_ERROR_CHAN(ftdmchan, "Invalid initial peer message type '%d'\n", event_clone->event_id);
+		} else {
+			SS7_INFO_CHAN(ftdmchan,"[CIC:%d]Tx IAM (Bridged)\n", sngss7_info->circuit->cic);
+			memcpy(&iam, &event_clone->event.siConEvnt, sizeof(iam));
+		}
+	} else if (sngss7_info->circuit->transparent_iam &&
 		sngss7_retrieve_iam(ftdmchan, &iam) == FTDM_SUCCESS) {
 		SS7_INFO_CHAN(ftdmchan,"[CIC:%d]Tx IAM (Transparent)\n", sngss7_info->circuit->cic);
 	} else {