From 0a11b9b4333eb960038feca7972470f3770a5cce Mon Sep 17 00:00:00 2001
From: Anthony Minessale <anthm@freeswitch.org>
Date: Thu, 18 Nov 2010 16:23:01 -0600
Subject: [PATCH] FS-2859

---
 src/include/switch_types.h |  4 +++-
 src/switch_rtp.c           | 49 +++++++++++++++++++++++++++++++++++++-
 2 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/src/include/switch_types.h b/src/include/switch_types.h
index c01638089f..12fac04a8b 100644
--- a/src/include/switch_types.h
+++ b/src/include/switch_types.h
@@ -471,7 +471,9 @@ typedef enum {
 	SWITCH_VAD_FLAG_TALKING = (1 << 0),
 	SWITCH_VAD_FLAG_EVENTS_TALK = (1 << 1),
 	SWITCH_VAD_FLAG_EVENTS_NOTALK = (1 << 2),
-	SWITCH_VAD_FLAG_CNG = (1 << 3)
+	SWITCH_VAD_FLAG_CNG = (1 << 3),
+/*      added to keep track when last normal packet sent */
+	SWITCH_VAD_NPACKET_SENT = (1 << 4)
 } switch_vad_flag_enum_t;
 typedef uint32_t switch_vad_flag_t;
 
diff --git a/src/switch_rtp.c b/src/switch_rtp.c
index ee1c4acf5e..e347212ad5 100644
--- a/src/switch_rtp.c
+++ b/src/switch_rtp.c
@@ -240,6 +240,7 @@ struct switch_rtp {
 
 	switch_time_t send_time;
 	switch_byte_t auto_adj_used;
+	int last_voicepkt;
 };
 
 struct switch_rtcp_senderinfo {
@@ -1356,6 +1357,7 @@ SWITCH_DECLARE(switch_status_t) switch_rtp_create(switch_rtp_t **new_rtp_session
 	rtp_session->pool = pool;
 	rtp_session->te = 101;
 	rtp_session->recv_te = 101;
+	rtp_session->last_voicepkt=0;
 
 	switch_mutex_init(&rtp_session->flag_mutex, SWITCH_MUTEX_NESTED, pool);
 	switch_mutex_init(&rtp_session->read_mutex, SWITCH_MUTEX_NESTED, pool);
@@ -3155,9 +3157,12 @@ static int rtp_common_write(switch_rtp_t *rtp_session,
 {
 	switch_size_t bytes, rtcp_bytes;
 	uint8_t send = 1;
+	uint8_t CNdata[10] = { 0 };
+	uint8_t sendCN = 0;
 	uint32_t this_ts = 0;
 	int ret;
 	switch_time_t now;
+	CNdata[0] = 65;
 
 	if (!switch_rtp_ready(rtp_session)) {
 		return SWITCH_STATUS_FALSE;
@@ -3239,9 +3244,15 @@ static int rtp_common_write(switch_rtp_t *rtp_session,
 		rtp_session->recv_msg.header.pt = 102;
 	}
 
+	if ( !switch_test_flag(rtp_session,SWITCH_RTP_FLAG_VAD ) )
+		switch_set_flag( rtp_session,SWITCH_RTP_FLAG_VAD);
+
+
+/*
 	if (switch_test_flag(rtp_session, SWITCH_RTP_FLAG_VAD) &&
 		rtp_session->recv_msg.header.pt == rtp_session->vad_data.read_codec->implementation->ianacode) {
-
+*/
+	if (switch_test_flag(rtp_session, SWITCH_RTP_FLAG_VAD)) {
 		int16_t decoded[SWITCH_RECOMMENDED_BUFFER_SIZE / sizeof(int16_t)] = { 0 };
 		uint32_t rate = 0;
 		uint32_t codec_flags = 0;
@@ -3290,6 +3301,7 @@ static int rtp_common_write(switch_rtp_t *rtp_session,
 						if (score > rtp_session->vad_data.bg_level && !switch_test_flag(&rtp_session->vad_data, SWITCH_VAD_FLAG_TALKING)) {
 							uint32_t diff = score - rtp_session->vad_data.bg_level;
 
+
 							if (rtp_session->vad_data.hangover_hits) {
 								rtp_session->vad_data.hangover_hits--;
 							}
@@ -3342,11 +3354,31 @@ static int rtp_common_write(switch_rtp_t *rtp_session,
 
 	this_ts = ntohl(send_msg->header.ts);
 
+
+	/* if previous normal packet is sent but this one is not scheduled to be sent, send a CN packet */
+	if ( !rtp_session->last_voicepkt  && send==0 ) {
+		send=1;
+		sendCN=1;
+		//switch_set_flag(&rtp_session->vad_data,SWITCH_VAD_NPACKET_SENT );
+		rtp_session->last_voicepkt=1;
+	}
+
 	if (!switch_rtp_ready(rtp_session) || rtp_session->sending_dtmf || !this_ts) {
 		send = 0;
 	}
 
+	/* we send CN automatically. ignore other attempts */
+	if ( send_msg->header.pt == rtp_session->cng_pt ){
+		send = 0;
+	}
+
+	
+
 	if (send) {
+		if ( !sendCN)
+			rtp_session->last_voicepkt=0;
+
+
 		send_msg->header.seq = htons(++rtp_session->seq);
 
 		if (switch_test_flag(rtp_session, SWITCH_RTP_FLAG_SECURE_SEND)) {
@@ -3441,6 +3473,18 @@ static int rtp_common_write(switch_rtp_t *rtp_session,
 			}
 		}
 
+		if ( sendCN ) {
+			int CNdatalen = 2;
+			rtp_session->cn++;
+			memcpy(send_msg->body, CNdata, CNdatalen);
+			bytes = CNdatalen + rtp_header_len;
+			payload = rtp_session->cng_pt;
+			send_msg->header.pt = rtp_session->cng_pt;
+			send_msg->header.m = 0;
+			rtp_session->last_voicepkt=1;
+		}
+
+
 
 		if (switch_socket_sendto(rtp_session->sock_output, rtp_session->remote_addr, 0, (void *) send_msg, &bytes) != SWITCH_STATUS_SUCCESS) {
 			rtp_session->seq--;
@@ -3523,6 +3567,9 @@ static int rtp_common_write(switch_rtp_t *rtp_session,
 		}
 	}
 
+	
+
+
 	if (rtp_session->remote_stun_addr) {
 		do_stun_ping(rtp_session);
 	}