selftests: net: Add test_vxlan_fdb_changelink.sh

Add a test to exercise the fix from the previous patch.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/net/Makefile

@@ -7,6 +7,7 @@ CFLAGS += -I../../../../usr/include/
 TEST_PROGS := run_netsocktests run_afpackettests test_bpf.sh netdevice.sh rtnetlink.sh
 TEST_PROGS += fib_tests.sh fib-onlink-tests.sh pmtu.sh udpgso.sh ip_defrag.sh
 TEST_PROGS += udpgso_bench.sh fib_rule_tests.sh msg_zerocopy.sh psock_snd.sh
+TEST_PROGS += test_vxlan_fdb_changelink.sh
 TEST_PROGS_EXTENDED := in_netns.sh
 TEST_GEN_FILES =  socket
 TEST_GEN_FILES += psock_fanout psock_tpacket msg_zerocopy

tools/testing/selftests/net/test_vxlan_fdb_changelink.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# Check FDB default-remote handling across "ip link set".
+
+check_remotes()
+{
+	local what=$1; shift
+	local N=$(bridge fdb sh dev vx | grep 00:00:00:00:00:00 | wc -l)
+
+	echo -ne "expected two remotes after $what\t"
+	if [[ $N != 2 ]]; then
+		echo "[FAIL]"
+		EXIT_STATUS=1
+	else
+		echo "[ OK ]"
+	fi
+}
+
+ip link add name vx up type vxlan id 2000 dstport 4789
+bridge fdb ap dev vx 00:00:00:00:00:00 dst 192.0.2.20 self permanent
+bridge fdb ap dev vx 00:00:00:00:00:00 dst 192.0.2.30 self permanent
+check_remotes "fdb append"
+
+ip link set dev vx type vxlan remote 192.0.2.30
+check_remotes "link set"
+
+ip link del dev vx
+exit $EXIT_STATUS