Re: [PATCH net-next V2 3/3] net: Add GRO support for vxlan traffic

On Tue, 2014-01-07 at 21:43 +0200, Or Gerlitz wrote:

On Tue, Jan 7, 2014 at 6:34 PM, Eric Dumazet [off-list ref] wrote:

quoted

On Tue, 2014-01-07 at 17:29 +0200, Or Gerlitz wrote:

quoted

Add gro handlers for vxlan using the udp gro infrastructure

quoted

 static void vxlan_notify_add_rx_port(struct sock *sk)
 {

@@ -568,6 +661,8 @@ static void vxlan_notify_add_rx_port(struct sock *sk)
                      dev->netdev_ops->ndo_add_vxlan_port(dev, sa_family,
                                                          port);
      }
+     if (sa_family == AF_INET)
+             udp_add_offload(&vxlan_offload, port);
      rcu_read_unlock();
 }

This means two vxlan tunnels can not share same port.
Is that a valid assertion ?

nope -- the vxlan driver opens a listener udp socket per per listening
port, but N > 1 vxlan tunnels can sit on that port, the driver does
further demuxing based on the vnid carried in the vxlan header, see
the call to vxlan_find_vni() from vxlan_rcv()
--

So if we use same port, it seems to me udp_del_offload() of the first
dismantled tunnel will remove the offload for the remaining tunnel.

You forgot to implement a refcount somehow.