Commit bd0d9e75 authored by Oscar Maes's avatar Oscar Maes Committed by Jakub Kicinski
Browse files

selftests: net: add test for dst hint mechanism with directed broadcast addresses 



Add a test for ensuring that the dst hint mechanism is used for
directed broadcast addresses.

This test relies on mausezahn for sending directed broadcast packets.
Additionally, a high GRO flush timeout is set to ensure that packets
will be received as lists.

The test determines if the hint mechanism was used by checking
the in_brd statistic using lnstat.

Signed-off-by: default avatarOscar Maes <oscmaes92@gmail.com>
Link: https://patch.msgid.link/20250819174642.5148-3-oscmaes92@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 1b8c5fa0

tools/testing/selftests/net/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -117,6 +117,7 @@ TEST_GEN_FILES += tfo 
TEST_PROGS += tfo_passive.sh

TEST_PROGS += broadcast_pmtu.sh

TEST_PROGS += ipv6_force_forwarding.sh

TEST_PROGS += route_hint.sh



# YNL files, must be before "include ..lib.mk"

YNL_GEN_FILES := busy_poller netlink-dumps

tools/testing/selftests/net/route_hint.sh

0 → 100755
+79 −0
Original line number Diff line number Diff line 
#!/bin/bash

# SPDX-License-Identifier: GPL-2.0



# This test ensures directed broadcast routes use dst hint mechanism



source lib.sh



CLIENT_IP4="192.168.0.1"

SERVER_IP4="192.168.0.2"

BROADCAST_ADDRESS="192.168.0.255"



setup() {

	setup_ns CLIENT_NS SERVER_NS



	ip -net "${SERVER_NS}" link add link1 type veth peer name link0 netns "${CLIENT_NS}"



	ip -net "${CLIENT_NS}" link set link0 up

	ip -net "${CLIENT_NS}" addr add "${CLIENT_IP4}/24" dev link0



	ip -net "${SERVER_NS}" link set link1 up

	ip -net "${SERVER_NS}" addr add "${SERVER_IP4}/24" dev link1



	ip netns exec "${CLIENT_NS}" ethtool -K link0 tcp-segmentation-offload off

	ip netns exec "${SERVER_NS}" sh -c "echo 500000000 > /sys/class/net/link1/gro_flush_timeout"

	ip netns exec "${SERVER_NS}" sh -c "echo 1 > /sys/class/net/link1/napi_defer_hard_irqs"

	ip netns exec "${SERVER_NS}" ethtool -K link1 generic-receive-offload on

}



cleanup() {

	ip -net "${SERVER_NS}" link del link1

	cleanup_ns "${CLIENT_NS}" "${SERVER_NS}"

}



directed_bcast_hint_test()

{

	local rc=0



	echo "Testing for directed broadcast route hint"



	orig_in_brd=$(ip netns exec "${SERVER_NS}" lnstat -j -i1 -c1 | jq '.in_brd')

	ip netns exec "${CLIENT_NS}" mausezahn link0 -a own -b bcast -A "${CLIENT_IP4}" \

		-B "${BROADCAST_ADDRESS}" -c1 -t tcp "sp=1-100,dp=1234,s=1,a=0" -p 5 -q

	sleep 1

	new_in_brd=$(ip netns exec "${SERVER_NS}" lnstat -j -i1 -c1 | jq '.in_brd')



	res=$(echo "${new_in_brd} - ${orig_in_brd}" | bc)



	if [ "${res}" -lt 100 ]; then

		echo "[ OK ]"

		rc="${ksft_pass}"

	else

		echo "[FAIL] expected in_brd to be under 100, got ${res}"

		rc="${ksft_fail}"

	fi



	return "${rc}"

}



if [ ! -x "$(command -v mausezahn)" ]; then

	echo "SKIP: Could not run test without mausezahn tool"

	exit "${ksft_skip}"

fi



if [ ! -x "$(command -v jq)" ]; then

	echo "SKIP: Could not run test without jq tool"

	exit "${ksft_skip}"

fi



if [ ! -x "$(command -v bc)" ]; then

	echo "SKIP: Could not run test without bc tool"

	exit "${ksft_skip}"

fi



trap cleanup EXIT



setup



directed_bcast_hint_test

exit $?