selftests: forwarding: Test IPv4 routes with IPv6 link-local nexthops

In addition to IPv4 multipath tests with IPv4 nexthops, also test IPv4
multipath with nexthops that use IPv6 link-local addresses.
Signed-off-by: NIdo Schimmel <idosch@nvidia.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

tools/testing/selftests/net/forwarding/router_mpath_nh.sh

@@ -280,6 +280,17 @@ multipath_test()
 	multipath4_test "Weighted MP 2:1" 2 1
 	multipath4_test "Weighted MP 11:45" 11 45
 
+	log_info "Running IPv4 multipath tests with IPv6 link-local nexthops"
+	ip nexthop replace id 101 via fe80:2::22 dev $rp12
+	ip nexthop replace id 102 via fe80:3::23 dev $rp13
+
+	multipath4_test "ECMP" 1 1
+	multipath4_test "Weighted MP 2:1" 2 1
+	multipath4_test "Weighted MP 11:45" 11 45
+
+	ip nexthop replace id 102 via 169.254.3.23 dev $rp13
+	ip nexthop replace id 101 via 169.254.2.22 dev $rp12
+
 	log_info "Running IPv6 multipath tests"
 	multipath6_test "ECMP" 1 1
 	multipath6_test "Weighted MP 2:1" 2 1