selftests: net: Add drop monitor test

Test that drop monitor correctly captures both software and hardware
originated packet drops.

# ./drop_monitor_tests.sh

Software drops test
    TEST: Capturing active software drops                               [ OK ]
    TEST: Capturing inactive software drops                             [ OK ]

Hardware drops test
    TEST: Capturing active hardware drops                               [ OK ]
    TEST: Capturing inactive hardware drops                             [ OK ]

Tests passed:   4
Tests failed:   0

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/net/Makefile

@@ -19,6 +19,7 @@ TEST_PROGS += txtimestamp.sh
 TEST_PROGS += vrf-xfrm-tests.sh
 TEST_PROGS += rxtimestamp.sh
 TEST_PROGS += devlink_port_split.py
+TEST_PROGS += drop_monitor_tests.sh
 TEST_PROGS_EXTENDED := in_netns.sh
 TEST_GEN_FILES =  socket nettest
 TEST_GEN_FILES += psock_fanout psock_tpacket msg_zerocopy reuseport_addr_any

tools/testing/selftests/net/config

@@ -30,3 +30,6 @@ CONFIG_NET_SCH_ETF=m
 CONFIG_NET_SCH_NETEM=y
 CONFIG_TEST_BLACKHOLE_DEV=m
 CONFIG_KALLSYMS=y
+CONFIG_TRACEPOINTS=y
+CONFIG_NET_DROP_MONITOR=m
+CONFIG_NETDEVSIM=m

tools/testing/selftests/net/drop_monitor_tests.sh

@@ -0,0 +1,215 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# This test is for checking drop monitor functionality.
+
+ret=0
+# Kselftest framework requirement - SKIP code is 4.
+ksft_skip=4
+
+# all tests in this script. Can be overridden with -t option
+TESTS="
+	sw_drops
+	hw_drops
+"
+
+IP="ip -netns ns1"
+TC="tc -netns ns1"
+DEVLINK="devlink -N ns1"
+NS_EXEC="ip netns exec ns1"
+NETDEVSIM_PATH=/sys/bus/netdevsim/
+DEV_ADDR=1337
+DEV=netdevsim${DEV_ADDR}
+DEVLINK_DEV=netdevsim/${DEV}
+
+log_test()
+{
+	local rc=$1
+	local expected=$2
+	local msg="$3"
+
+	if [ ${rc} -eq ${expected} ]; then
+		printf "    TEST: %-60s  [ OK ]\n" "${msg}"
+		nsuccess=$((nsuccess+1))
+	else
+		ret=1
+		nfail=$((nfail+1))
+		printf "    TEST: %-60s  [FAIL]\n" "${msg}"
+	fi
+}
+
+setup()
+{
+	modprobe netdevsim &> /dev/null
+
+	set -e
+	ip netns add ns1
+	$IP link add dummy10 up type dummy
+
+	$NS_EXEC echo "$DEV_ADDR 1" > ${NETDEVSIM_PATH}/new_device
+	udevadm settle
+	local netdev=$($NS_EXEC ls ${NETDEVSIM_PATH}/devices/${DEV}/net/)
+	$IP link set dev $netdev up
+
+	set +e
+}
+
+cleanup()
+{
+	$NS_EXEC echo "$DEV_ADDR" > ${NETDEVSIM_PATH}/del_device
+	ip netns del ns1
+}
+
+sw_drops_test()
+{
+	echo
+	echo "Software drops test"
+
+	setup
+
+	local dir=$(mktemp -d)
+
+	$TC qdisc add dev dummy10 clsact
+	$TC filter add dev dummy10 egress pref 1 handle 101 proto ip \
+		flower dst_ip 192.0.2.10 action drop
+
+	$NS_EXEC mausezahn dummy10 -a 00:11:22:33:44:55 -b 00:aa:bb:cc:dd:ee \
+		-A 192.0.2.1 -B 192.0.2.10 -t udp sp=12345,dp=54321 -c 0 -q \
+		-d 100msec &
+	timeout 5 dwdump -o sw -w ${dir}/packets.pcap
+	(( $(tshark -r ${dir}/packets.pcap \
+		-Y 'ip.dst == 192.0.2.10' 2> /dev/null | wc -l) != 0))
+	log_test $? 0 "Capturing active software drops"
+
+	rm ${dir}/packets.pcap
+
+	{ kill %% && wait %%; } 2>/dev/null
+	timeout 5 dwdump -o sw -w ${dir}/packets.pcap
+	(( $(tshark -r ${dir}/packets.pcap \
+		-Y 'ip.dst == 192.0.2.10' 2> /dev/null | wc -l) == 0))
+	log_test $? 0 "Capturing inactive software drops"
+
+	rm -r $dir
+
+	cleanup
+}
+
+hw_drops_test()
+{
+	echo
+	echo "Hardware drops test"
+
+	setup
+
+	local dir=$(mktemp -d)
+
+	$DEVLINK trap set $DEVLINK_DEV trap blackhole_route action trap
+	timeout 5 dwdump -o hw -w ${dir}/packets.pcap
+	(( $(tshark -r ${dir}/packets.pcap \
+		-Y 'net_dm.hw_trap_name== blackhole_route' 2> /dev/null \
+		| wc -l) != 0))
+	log_test $? 0 "Capturing active hardware drops"
+
+	rm ${dir}/packets.pcap
+
+	$DEVLINK trap set $DEVLINK_DEV trap blackhole_route action drop
+	timeout 5 dwdump -o hw -w ${dir}/packets.pcap
+	(( $(tshark -r ${dir}/packets.pcap \
+		-Y 'net_dm.hw_trap_name== blackhole_route' 2> /dev/null \
+		| wc -l) == 0))
+	log_test $? 0 "Capturing inactive hardware drops"
+
+	rm -r $dir
+
+	cleanup
+}
+
+################################################################################
+# usage
+
+usage()
+{
+	cat <<EOF
+usage: ${0##*/} OPTS
+
+        -t <test>   Test(s) to run (default: all)
+                    (options: $TESTS)
+EOF
+}
+
+################################################################################
+# main
+
+while getopts ":t:h" opt; do
+	case $opt in
+		t) TESTS=$OPTARG;;
+		h) usage; exit 0;;
+		*) usage; exit 1;;
+	esac
+done
+
+if [ "$(id -u)" -ne 0 ];then
+	echo "SKIP: Need root privileges"
+	exit $ksft_skip;
+fi
+
+if [ ! -x "$(command -v ip)" ]; then
+	echo "SKIP: Could not run test without ip tool"
+	exit $ksft_skip
+fi
+
+if [ ! -x "$(command -v devlink)" ]; then
+	echo "SKIP: Could not run test without devlink tool"
+	exit $ksft_skip
+fi
+
+if [ ! -x "$(command -v tshark)" ]; then
+	echo "SKIP: Could not run test without tshark tool"
+	exit $ksft_skip
+fi
+
+if [ ! -x "$(command -v dwdump)" ]; then
+	echo "SKIP: Could not run test without dwdump tool"
+	exit $ksft_skip
+fi
+
+if [ ! -x "$(command -v udevadm)" ]; then
+	echo "SKIP: Could not run test without udevadm tool"
+	exit $ksft_skip
+fi
+
+if [ ! -x "$(command -v timeout)" ]; then
+	echo "SKIP: Could not run test without timeout tool"
+	exit $ksft_skip
+fi
+
+if [ ! -x "$(command -v mausezahn)" ]; then
+	echo "SKIP: Could not run test without mausezahn tool"
+	exit $ksft_skip
+fi
+
+tshark -G fields 2> /dev/null | grep -q net_dm
+if [ $? -ne 0 ]; then
+	echo "SKIP: tshark too old, missing net_dm dissector"
+	exit $ksft_skip
+fi
+
+# start clean
+cleanup &> /dev/null
+
+for t in $TESTS
+do
+	case $t in
+	sw_drops|sw)			sw_drops_test;;
+	hw_drops|hw)			hw_drops_test;;
+
+	help) echo "Test names: $TESTS"; exit 0;;
+	esac
+done
+
+if [ "$TESTS" != "none" ]; then
+	printf "\nTests passed: %3d\n" ${nsuccess}
+	printf "Tests failed: %3d\n"   ${nfail}
+fi
+
+exit $ret