Commit 4ad96a7c authored by Kibaek Yoo's avatar Kibaek Yoo Committed by Jakub Kicinski
Browse files

selftests: net: add macvlan multicast test for shared source MAC 



Add a selftest that verifies multicast delivery to a macvlan bridge
port when the source MAC of the incoming frame matches the macvlan's
own MAC address.

This scenario occurs with protocols like VRRP where multiple hosts
share the same virtual MAC address. Without the corresponding kernel
change, macvlan bridge mode does not handle this case and the
multicast frame is not delivered.

Signed-off-by: default avatarKibaek Yoo <psykibaek@gmail.com>
Link: https://patch.msgid.link/20260228071613.4360-2-psykibaek@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent b52363f7

tools/testing/selftests/net/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -55,6 +55,7 @@ TEST_PROGS := \ 
	l2tp.sh \

	link_netns.py \

	lwt_dst_cache_ref_loop.sh \

	macvlan_mcast_shared_mac.sh \

	msg_zerocopy.sh \

	nat6to4.sh \

	ndisc_unsolicited_na_test.sh \

tools/testing/selftests/net/macvlan_mcast_shared_mac.sh

0 → 100755
+93 −0
Original line number Diff line number Diff line 
#!/bin/bash

# SPDX-License-Identifier: GPL-2.0

#

# Test multicast delivery to macvlan bridge ports when the source MAC

# matches the macvlan's own MAC address (e.g., VRRP virtual MAC shared

# across multiple hosts).

#

# Topology:

#

#   NS_SRC                          NS_BRIDGE

#   veth_src (SHARED_MAC) <----->  veth_dst

#                                     |

#                                     +-- macvlan0 (bridge mode, SHARED_MAC)

#

# A multicast packet sent from NS_SRC with source MAC equal to

# macvlan0's MAC must still be delivered to macvlan0.



source lib.sh



SHARED_MAC="00:00:5e:00:01:01"

MCAST_ADDR="239.0.0.1"



setup() {

	setup_ns NS_SRC NS_BRIDGE



	ip -net "${NS_BRIDGE}" link add veth_dst type veth \

		peer name veth_src netns "${NS_SRC}"



	ip -net "${NS_SRC}" link set veth_src address "${SHARED_MAC}"

	ip -net "${NS_SRC}" link set veth_src up

	ip -net "${NS_SRC}" addr add 192.168.1.1/24 dev veth_src



	ip -net "${NS_BRIDGE}" link set veth_dst up



	ip -net "${NS_BRIDGE}" link add macvlan0 link veth_dst \

		type macvlan mode bridge

	ip -net "${NS_BRIDGE}" link set macvlan0 address "${SHARED_MAC}"

	ip -net "${NS_BRIDGE}" link set macvlan0 up

	ip -net "${NS_BRIDGE}" addr add 192.168.1.2/24 dev macvlan0



	# Accept all multicast so the mc_filter passes for any group.

	ip -net "${NS_BRIDGE}" link set macvlan0 allmulticast on

}



cleanup() {

	rm -f "${CAPFILE}" "${CAPOUT}"

	cleanup_ns "${NS_SRC}" "${NS_BRIDGE}"

}



test_macvlan_mcast_shared_mac() {

	CAPFILE=$(mktemp)

	CAPOUT=$(mktemp)



	echo "Testing multicast delivery to macvlan with shared source MAC"



	# Listen for one ICMP packet on macvlan0.

	timeout 5s ip netns exec "${NS_BRIDGE}" \

		tcpdump -i macvlan0 -c 1 -w "${CAPFILE}" icmp &> "${CAPOUT}" &

	local pid=$!

	if ! slowwait 1 grep -qs "listening" "${CAPOUT}"; then

		echo "[FAIL] tcpdump did not start listening"

		return "${ksft_fail}"

	fi



	# Send multicast ping from NS_SRC; source MAC equals macvlan0's MAC.

	ip netns exec "${NS_SRC}" \

		ping -W 0.1 -c 3 -I veth_src "${MCAST_ADDR}" &> /dev/null



	wait "${pid}"



	local count

	count=$(tcpdump -r "${CAPFILE}" 2>/dev/null | wc -l)

	if [[ "${count}" -ge 1 ]]; then

		echo "[ OK ]"

		return "${ksft_pass}"

	else

		echo "[FAIL] expected at least 1 ICMP packet on macvlan0," \

			"got ${count}"

		return "${ksft_fail}"

	fi

}



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

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

	exit "${ksft_skip}"

fi



trap cleanup EXIT



setup

test_macvlan_mcast_shared_mac



exit $?