vxlan: advertise link netns in fdb messages

Previous commit is based on a wrong assumption, fdb messages are always sent
into the netns where the interface stands (see vxlan_fdb_notify()).

These fdb messages doesn't embed the rtnl attribute IFLA_LINK_NETNSID, thus we
need to add it (useful to interpret NDA_IFINDEX or NDA_DST for example).

Note also that vxlan_nlmsg_size() was not updated.

Fixes: 193523bf9373 ("vxlan: advertise netns of vxlan dev in fdb msg")
Signed-off-by: Nicolas Dichtel <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/vxlan.c

···
 	ndm->ndm_type = RTN_UNICAST;
 
 	if (!net_eq(dev_net(vxlan->dev), vxlan->net) &&
-	    nla_put_s32(skb, NDA_NDM_IFINDEX_NETNSID,
-			peernet2id(vxlan->net, dev_net(vxlan->dev))))
+	    nla_put_s32(skb, NDA_LINK_NETNSID,
+			peernet2id(dev_net(vxlan->dev), vxlan->net)))
 		goto nla_put_failure;
 
 	if (send_eth && nla_put(skb, NDA_LLADDR, ETH_ALEN, &fdb->eth_addr))
···
 		+ nla_total_size(sizeof(__be16)) /* NDA_PORT */
 		+ nla_total_size(sizeof(__be32)) /* NDA_VNI */
 		+ nla_total_size(sizeof(__u32)) /* NDA_IFINDEX */
+		+ nla_total_size(sizeof(__s32)) /* NDA_LINK_NETNSID */
 		+ nla_total_size(sizeof(struct nda_cacheinfo));
 }
 

include/uapi/linux/neighbour.h

···
 	NDA_VNI,
 	NDA_IFINDEX,
 	NDA_MASTER,
-	NDA_NDM_IFINDEX_NETNSID,
+	NDA_LINK_NETNSID,
 	__NDA_MAX
 };