vxlan: Avoid creating fdb entry with NULL destination

Commit afbd8bae9c798c5cdbe4439d3a50536b5438247c
   vxlan: add implicit fdb entry for default destination
creates an implicit fdb entry for default destination. This results
in an invalid fdb entry if default destination is not specified.
For ex:
  ip link add vxlan1 type vxlan id 100
creates the following fdb entry
  00:00:00:00:00:00 dev vxlan1 dst 0.0.0.0 self permanent

This patch fixes this issue by creating an fdb entry only if a
valid default destination is specified.

Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 13 insertions, 9 deletions

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 2400b1beddd5..d1292fe746bc 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -2490,15 +2490,19 @@ static int vxlan_newlink(struct net *net, struct net_device *dev,
 
         SET_ETHTOOL_OPS(dev, &vxlan_ethtool_ops);
 
-        /* create an fdb entry for default destination */
-        err = vxlan_fdb_create(vxlan, all_zeros_mac,
-                               &vxlan->default_dst.remote_ip,
-                               NUD_REACHABLE|NUD_PERMANENT,
-                               NLM_F_EXCL|NLM_F_CREATE,
-                               vxlan->dst_port, vxlan->default_dst.remote_vni,
-                               vxlan->default_dst.remote_ifindex, NTF_SELF);
-        if (err)
-                return err;
+        /* create an fdb entry for a valid default destination */
+        if (!vxlan_addr_any(&vxlan->default_dst.remote_ip)) {
+                err = vxlan_fdb_create(vxlan, all_zeros_mac,
+                                       &vxlan->default_dst.remote_ip,
+                                       NUD_REACHABLE|NUD_PERMANENT,
+                                       NLM_F_EXCL|NLM_F_CREATE,
+                                       vxlan->dst_port,
+                                       vxlan->default_dst.remote_vni,
+                                       vxlan->default_dst.remote_ifindex,
+                                       NTF_SELF);
+                if (err)
+                        return err;
+        }
 
         err = register_netdevice(dev);
         if (err) {