From c290d7292e43b1f67c61ecb4a58081545e562cb5 Mon Sep 17 00:00:00 2001
From: Philipp Maier <pmaier@sysmocom.de>
Date: Tue, 24 Jul 2018 18:51:36 +0200
Subject: [PATCH] MGCP_Test: check payload type of received RTP packets

When an RTP packet is received, the payload type is not checked,
so we will not detect if the MGW emits packets with a wrong payload
type for some reason.

- Introduce a statistics counter that counts packets with wrong PT
- Update testcases so that they check for the statistics for wrong
  PT count.

Change-Id: I83d4b04656a16ced624024245a2fcb7a0ad48a8a
Related: OS#3384
---
 library/RTP_Emulation.ttcn |  7 +++++++
 mgw/MGCP_Test.ttcn         | 29 +++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/library/RTP_Emulation.ttcn b/library/RTP_Emulation.ttcn
index 71cd8dbb1..2a358a951 100644
--- a/library/RTP_Emulation.ttcn
+++ b/library/RTP_Emulation.ttcn
@@ -116,6 +116,8 @@ type record RtpemStats {
 	integer num_pkts_rx_err_seq,
 	/* number of packets received wrong timestamp */
 	integer num_pkts_rx_err_ts,
+	/* number of packets received wrong payload type */
+	integer num_pkts_rx_err_pt,
 	/* number of packets received during Rx disable */
 	integer num_pkts_rx_err_disabled
 }
@@ -127,6 +129,7 @@ const RtpemStats c_RtpemStatsReset := {
 	bytes_payload_rx := 0,
 	num_pkts_rx_err_seq := 0,
 	num_pkts_rx_err_ts := 0,
+	num_pkts_rx_err_pt := 0,
 	num_pkts_rx_err_disabled := 0
 }
 
@@ -399,7 +402,11 @@ function f_main() runs on RTP_Emulation_CT
 		/* process received RTCP/RTP if receiver enabled */
 		[g_rx_enabled] RTP.receive(tr_rtp) -> value rx_rtp {
 			//log("RX RTP: ", rx_rtp);
+
 			/* increment counters */
+			if (rx_rtp.msg.rtp.payload_type != g_cfg.tx_payload_type) {
+				g_stats_rtp.num_pkts_rx_err_pt := g_stats_rtp.num_pkts_rx_err_pt+1;
+			}
 			g_stats_rtp.num_pkts_rx := g_stats_rtp.num_pkts_rx+1;
 			g_stats_rtp.bytes_payload_rx := g_stats_rtp.bytes_payload_rx +
 								lengthof(rx_rtp.msg.rtp.data);
diff --git a/mgw/MGCP_Test.ttcn b/mgw/MGCP_Test.ttcn
index 82ed608bc..264ac285f 100644
--- a/mgw/MGCP_Test.ttcn
+++ b/mgw/MGCP_Test.ttcn
@@ -970,6 +970,9 @@ module MGCP_Test {
 		if (stats.num_pkts_rx_err_ts != 0) {
 			setverdict(fail);
 		}
+		if (stats.num_pkts_rx_err_pt != 0) {
+			setverdict(fail);
+		}
 		if (stats.num_pkts_rx_err_disabled != 0) {
 			setverdict(fail);
 		}
@@ -1008,6 +1011,9 @@ module MGCP_Test {
 		if (stats.num_pkts_rx_err_ts != 0) {
 			setverdict(fail);
 		}
+		if (stats.num_pkts_rx_err_pt != 0) {
+			setverdict(fail);
+		}
 		if (stats.num_pkts_rx_err_disabled != 0) {
 			setverdict(fail);
 		}
@@ -1062,6 +1068,11 @@ module MGCP_Test {
 			mtc.stop;
 		}
 
+		if (stats[0].num_pkts_rx_err_pt > 0 or stats[1].num_pkts_rx_err_pt > 0) {
+			setverdict(fail, "RTP packets with wrong payload type received");
+			mtc.stop;
+		}
+
 		setverdict(pass);
 	}
 
@@ -1163,12 +1174,20 @@ module MGCP_Test {
 			setverdict(fail, "number of packets not within normal parameters");
 			mtc.stop;
 		}
+		if (stats[0].num_pkts_rx_err_pt > 0) {
+			setverdict(fail, "RTP packets with wrong payload type received");
+			mtc.stop;
+		}
 
 		temp := stats[1].num_pkts_tx - num_pkts_tx[1] - stats[0].num_pkts_rx;
 		if (temp > 3 or temp < -3) {
 			setverdict(fail, "number of packets not within normal parameters");
 			mtc.stop;
 		}
+		if (stats[0].num_pkts_rx_err_pt > 0) {
+			setverdict(fail, "RTP packets with wrong payload type received");
+			mtc.stop;
+		}
 
 		/* Tear down */
 		f_flow_delete(RTPEM[0]);
@@ -1221,6 +1240,11 @@ module MGCP_Test {
 			mtc.stop;
 		}
 
+		if (stats[0].num_pkts_rx_err_pt > 0 or stats[1].num_pkts_rx_err_pt > 0) {
+			setverdict(fail, "RTP packets with wrong payload type received");
+			mtc.stop;
+		}
+
 		setverdict(pass);
 	}
 
@@ -1284,6 +1308,11 @@ module MGCP_Test {
 			mtc.stop;
 		}
 
+		if (stats[0].num_pkts_rx_err_pt > 0 or stats[1].num_pkts_rx_err_pt > 0) {
+			setverdict(fail, "RTP packets with wrong payload type received");
+			mtc.stop;
+		}
+
 		setverdict(pass);
 	}