TEL-6685: Re-add bridge_forward_cng_interval from bridge_forward_cng_once

src/include/switch_types.h

@@ -1706,6 +1706,7 @@ typedef enum {
 	CF_EARLY_MEDIA_SIP_UPDATE,
 	CF_DENOISED,
 	CF_REMOTE_RECOVERED,
+	CF_FORWARD_CNG_ONCE,
 	/* WARNING: DO NOT ADD ANY FLAGS BELOW THIS LINE */
 	/* IF YOU ADD NEW ONES CHECK IF THEY SHOULD PERSIST OR ZERO THEM IN switch_core_session.c switch_core_session_request_xml() */
 	CF_FLAG_MAX

src/switch_core_io.c

@@ -709,6 +709,7 @@ SWITCH_DECLARE(switch_status_t) switch_core_session_read_frame(switch_core_sessi
 			switch_media_bug_t *bp;
 			switch_bool_t ok = SWITCH_TRUE;
 			int prune = 0;
+			int bp_cng = switch_test_flag(read_frame, SFF_CNG);
 			switch_thread_rwlock_rdlock(session->bug_rwlock);
 
 			for (bp = session->bugs; bp; bp = bp->next) {
@@ -744,6 +745,11 @@ SWITCH_DECLARE(switch_status_t) switch_core_session_read_frame(switch_core_sessi
 						if ((ok = bp->callback(bp, bp->user_data, SWITCH_ABC_TYPE_READ_REPLACE)) == SWITCH_TRUE) {
 							read_frame = bp->read_replace_frame_out;
 						}
+
+						// Check if updated read_frame is a CNG
+						if (!bp_cng && switch_test_flag(read_frame, SFF_CNG)) {
+							flag |= SFF_CNG;
+						}
 					}
 				}
 
@@ -973,6 +979,8 @@ SWITCH_DECLARE(switch_status_t) switch_core_session_read_frame(switch_core_sessi
 	} else {
 		if (flag & SFF_CNG) {
 			switch_set_flag((*frame), SFF_CNG);
+		} else {
+			switch_clear_flag((*frame), SFF_CNG);
 		}
 
 		if (session->bugs) {

src/switch_ivr_bridge.c

@@ -451,6 +451,9 @@ static void *audio_bridge_thread(switch_thread_t *thread, void *obj)
 	const char *banner_file = NULL;
 	int played_banner = 0, banner_counter = 0;
 	int pass_val = 0, last_pass_val = 0;
+	int sent_cng = 0, sent_cng_interval = 0;
+	switch_time_t last_sent_cng = 0;
+	const char *bridge_forward_cng_interval = NULL;
 
 #ifdef SWITCH_VIDEO_IN_THREADS
 	struct vid_helper vh = { 0 };
@@ -593,6 +596,26 @@ static void *audio_bridge_thread(switch_thread_t *thread, void *obj)
 			max_continuous_silence_ms = 5000; 
 		}
 	}
+
+	if (switch_channel_var_true(chan_a, "bridge_forward_cng_once")) {
+#if DEBUG_RTP
+		switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_NOTICE, "Audio bridge thread: forward_cng %p\n", (void*)session_a);
+#endif
+		switch_channel_set_flag(chan_b, CF_FORWARD_CNG_ONCE);
+	}
+
+	if ((bridge_forward_cng_interval = switch_channel_get_variable(chan_a, "bridge_forward_cng_interval"))) {
+		if (switch_true(bridge_forward_cng_interval)) {
+			sent_cng_interval = 5000;
+		} else {
+			if ((sent_cng_interval = atoi(bridge_forward_cng_interval)) < 0) {
+				sent_cng_interval = 0;
+			}
+		}
+		if (sent_cng_interval > 0) {
+			switch_channel_set_flag(chan_b, CF_FORWARD_CNG_ONCE);
+		}
+	}
 
 	if ((silence_var = switch_channel_get_variable(chan_a, "bridge_generate_comfort_noise"))) {
 #if DEBUG_RTP
@@ -1116,6 +1139,17 @@ static void *audio_bridge_thread(switch_thread_t *thread, void *obj)
 					switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_NOTICE, "Audio bridge thread: skip write frame, reason: CF_ACCEPT_CNG %p %p -> %p\n", (void*)session_b, (void*)session_a, (void*)session_b);
 #endif
 					continue;
+				} else if (switch_channel_test_flag(chan_b, CF_FORWARD_CNG_ONCE)) {
+					if (!sent_cng && !last_sent_cng) {
+						sent_cng = 1;
+						if (sent_cng_interval) {
+							last_sent_cng = switch_time_now();
+						}
+					} else if (sent_cng && last_sent_cng && ((switch_time_now() - last_sent_cng) / 1000) > sent_cng_interval) {
+						last_sent_cng = switch_time_now();
+					} else {
+						continue;
+					}
 				}
 			} else {
 				if (silence_threshold && is_silence_frame(read_frame, silence_threshold, &read_impl)) {
@@ -1127,6 +1161,8 @@ static void *audio_bridge_thread(switch_thread_t *thread, void *obj)
 				} else {
 					total_silence_frame_ms = 0;
 				}
+				sent_cng = 0;
+				last_sent_cng = 0;
 			}
 
 			if (switch_channel_test_flag(chan_a, CF_BRIDGE_NOWRITE)) {