1 files changed, 43 insertions, 0 deletions
diff --git a/tools/testing/selftests/net/forwarding/lib.sh b/tools/testing/selftests/net/forwarding/lib.sh
index 977fc2b326a2..927f9ba49e08 100644
--- a/tools/testing/selftests/net/forwarding/lib.sh
+++ b/tools/testing/selftests/net/forwarding/lib.sh
@@ -1227,3 +1227,46 @@ stop_traffic()
 	# Suppress noise from killing mausezahn.
 	{ kill %% && wait %%; } 2>/dev/null
 }
+
+tcpdump_start()
+{
+	local if_name=$1; shift
+	local ns=$1; shift
+
+	capfile=$(mktemp)
+	capout=$(mktemp)
+
+	if [ -z $ns ]; then
+		ns_cmd=""
+	else
+		ns_cmd="ip netns exec ${ns}"
+	fi
+
+	if [ -z $SUDO_USER ] ; then
+		capuser=""
+	else
+		capuser="-Z $SUDO_USER"
+	fi
+
+	$ns_cmd tcpdump -e -n -Q in -i $if_name \
+		-s 65535 -B 32768 $capuser -w $capfile > "$capout" 2>&1 &
+	cappid=$!
+
+	sleep 1
+}
+
+tcpdump_stop()
+{
+	$ns_cmd kill $cappid
+	sleep 1
+}
+
+tcpdump_cleanup()
+{
+	rm $capfile $capout
+}
+
+tcpdump_show()
+{
+	tcpdump -e -n -r $capfile 2>&1
+}