vxlan: fdb: allow specifying multiple destinations for zero MAC

The zero MAC entry in the fdb is used as default destination. With
multiple default destinations it is possible to use vxlan in
environments that disable multicast on the infrastructure level, e.g.
public clouds.
Signed-off-by: NMike Rapoport <mike.rapoport@ravellosystems.com>
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>

drivers/net/vxlan.c

@@ -458,7 +458,8 @@ static int vxlan_fdb_create(struct vxlan_dev *vxlan,
 			notify = 1;
 		}
 		if ((flags & NLM_F_APPEND) &&
-		    is_multicast_ether_addr(f->eth_addr)) {
+		    (is_multicast_ether_addr(f->eth_addr) ||
+		     is_zero_ether_addr(f->eth_addr))) {
 			int rc = vxlan_fdb_append(f, ip, port, vni, ifindex);
 
 			if (rc < 0)