Subject: Re: [PATCH net 0/2] lwtunnel: make it really work, for IPv4

From: Jiri Benc <[email-masked]>
Date: Wed, 23 Sep 2015 16:29:27 +0200

On Wed, 23 Sep 2015 07:17:53 -0500, Eric W. Biederman wrote:
> Assuming the transport is UDP then it would be a UDP socket.  That
> socket will have all of the information needed to construct the outer
> header as the receive path of that socket removes the outer header.
> 
> I admit you can't use the cached dst.  It is the wrong on that socket.
> 
> My point is that if we have the UDP socket and we have the sk we have
> all of the information we need to compute the reverse dst.

That (single) UDP socket may represent many tunnels with different
parameters. Knowing the socket is still not enough to construct the
data. The only place where the needed data is stored is routing table
which won't help us much for ARP, and the metadata dst attached to the
incoming skb.

 Jiri

-- 
Jiri Benc