Merge branch 'drop_monitor-Convert-to-use-devlink-tracepoint'

Ido Schimmel says:

====================
drop_monitor: Convert to use devlink tracepoint

Drop monitor is able to monitor both software and hardware originated
drops. Software drops are monitored by having drop monitor register its
probe on the 'kfree_skb' tracepoint. Hardware originated drops are
monitored by having devlink call into drop monitor whenever it receives
a dropped packet from the underlying hardware.

This patch set converts drop monitor to monitor both software and
hardware originated drops in the same way - by registering its probe on
the relevant tracepoint.

In addition to drop monitor being more consistent, it is now also
possible to build drop monitor as module instead of as a builtin and
still monitor hardware originated drops. Initially, CONFIG_NET_DEVLINK
implied CONFIG_NET_DROP_MONITOR, but after commit def2fbffe62c
("kconfig: allow symbols implied by y to become m") we can have
CONFIG_NET_DEVLINK=y and CONFIG_NET_DROP_MONITOR=m and hardware
originated drops will not be monitored.

Patch set overview:

Patch #1 adds a tracepoint in devlink for trap reports.

Patch #2 prepares probe functions in drop monitor for the new
tracepoint.

Patch #3 converts drop monitor to use the new tracepoint.

Patches #4-#6 perform cleanups after the conversion.

Patch #7 adds a test case for drop monitor. Both software originated
drops and hardware originated drops (using netdevsim) are tested.

Tested:

| CONFIG_NET_DEVLINK | CONFIG_NET_DROP_MONITOR | Build | SW drops | HW drops |
| -------------------|-------------------------|-------|----------|----------|
|          y         |            y            |   v   |     v    |     v    |
|          y         |            m            |   v   |     v    |     v    |
|          y         |            n            |   v   |     x    |     x    |
|          n         |            y            |   v   |     v    |     x    |
|          n         |            m            |   v   |     v    |     x    |
|          n         |            n            |   v   |     x    |     x    |
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 219 insertions, 0 deletions

diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index 9491bbaa0831..52923eb08934 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/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
diff --git a/tools/testing/selftests/net/config b/tools/testing/selftests/net/config
index 5a57ea02802d..43649242adc0 100644
--- a/tools/testing/selftests/net/config
+++ b/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
diff --git a/tools/testing/selftests/net/drop_monitor_tests.sh b/tools/testing/selftests/net/drop_monitor_tests.sh
new file mode 100755
index 000000000000..b7650e30d18b
--- /dev/null
+++ b/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