selftests: fib-onlink: Add a test case for IPv4 multicast gateway

A multicast gateway address should be rejected when "onlink" is
specified, but it is only tested as part of the IPv6 tests. Add an
equivalent IPv4 test.

 # ./fib-onlink-tests.sh -v
 [...]
 COMMAND: ip ro add table 254 169.254.101.12/32 via 233.252.0.1 dev veth1 onlink
 Error: Nexthop has invalid gateway.

 TEST: Invalid gw - multicast address                      [ OK ]
 [...]
 COMMAND: ip ro add table 1101 169.254.102.12/32 via 233.252.0.1 dev veth5 onlink
 Error: Nexthop has invalid gateway.

 TEST: Invalid gw - multicast address, VRF                 [ OK ]
 [...]
 Tests passed:  37
 Tests failed:   0

Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20260111120813.159799-4-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/tools/testing/selftests/net/fib-onlink-tests.sh b/tools/testing/selftests/net/fib-onlink-tests.sh
index 63477be859e3e3983ca1c417bfe6ed2897bb07b1..7a0fd7a91e4eb71e2299755a68b43073da59a936 100755 (executable)
--- a/tools/testing/selftests/net/fib-onlink-tests.sh
+++ b/tools/testing/selftests/net/fib-onlink-tests.sh
@@ -72,7 +72,8 @@ declare -A TEST_NET4IN6IN6
 TEST_NET4IN6[1]=10.1.1.254
 TEST_NET4IN6[2]=10.2.1.254
 
-# mcast address
+# mcast addresses
+MCAST4=233.252.0.1
 MCAST6=ff02::1
 
 VRF=lisa
@@ -310,9 +311,13 @@ invalid_onlink_ipv4()
 {
        run_ip 254 ${TEST_NET4[1]}.11 ${V4ADDRS[p1]} ${NETIFS[p1]} 2 \
                "Invalid gw - local unicast address"
+       run_ip 254 ${TEST_NET4[1]}.12 ${MCAST4} ${NETIFS[p1]} 2 \
+               "Invalid gw - multicast address"
 
        run_ip ${VRF_TABLE} ${TEST_NET4[2]}.11 ${V4ADDRS[p5]} ${NETIFS[p5]} 2 \
                "Invalid gw - local unicast address, VRF"
+       run_ip ${VRF_TABLE} ${TEST_NET4[2]}.12 ${MCAST4} ${NETIFS[p5]} 2 \
+               "Invalid gw - multicast address, VRF"
 
        run_ip 254 ${TEST_NET4[1]}.101 ${V4ADDRS[p1]} "" 2 "No nexthop device given"
 }