[Bloat] TCP TFO client behaviour

[Eric Dumazet]

On Tue, 2012-12-11 at 22:18 +0530, Ketan Kulkarni wrote:
> Hi,
> I am testing tcp tfo behavior with httping client and polipo server.
> 
> One observation from my TFO testing  -If for a connection server sends
> a cookie to client, client always does TFO for subsequent connections.
> This is ok.
> 
> If for some reason, server stops supporting TFO (either because server
> got restarted without TFO support (in my case) or because path changed
> and the nw node is dropping packet with unknown syn option or
> stripping the option), client does not clear up its cookie cache. It
> always sends data in syn and server never acks the syn-data and client
> retransmits.
> 
> As per kernel code -if syn-data is not acked it is retransmitted
> immediately - with the assumption first syn was dropped (but the
> assumption server stopped supporting TFO might not have been
> considered)
> 
> My opinion is to flush the cookie for this server and re-attempt the
> cookie "negotiation" on subsequent connection.
> 
> Your thoughts?

I really wonder why this is sent to these lists instead of netdev ?