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From: David Miller <davem@davemloft.net>
To: dada1@cosmosbay.com
Cc: netdev@vger.kernel.org, ilpo.jarvinen@helsinki.fi
Subject: Re: [RFC] tcp: allow timestamps even if SYN packet has tsval=0
Date: Wed, 11 Mar 2009 09:24:25 -0700 (PDT)	[thread overview]
Message-ID: <20090311.092425.203553937.davem@davemloft.net> (raw)
In-Reply-To: <49B7D1F2.5090504@cosmosbay.com>

From: Eric Dumazet <dada1@cosmosbay.com>
Date: Wed, 11 Mar 2009 16:00:02 +0100

> [PATCH] tcp: allow timestamps even if SYN packet has tsval=0
> 
> Some systems send SYN packets with apparently wrong RFC1323 timestamp
> option values [timestamp tsval=0 tsecr=0].
> It might be for security reasons (http://www.secuobs.com/plugs/25220.shtml )
> 
> Linux TCP stack ignores this option and sends back a SYN+ACK packet
> without timestamp option, thus many TCP flows cannot use timestamps
> and lose some benefit of RFC1323.
> 
> Other operating systems seem to not care about initial tsval value, and let
> tcp flows to negotiate timestamp option.
> 
> Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>

And amusingly even Linux didn't care for ipv6 TCP sockets ;-)

Applied to net-next-2.6, thanks Eric.

  reply	other threads:[~2009-03-11 16:24 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-03-11 12:17 [RFC] tcp: allow timestamps even if SYN packet has tsval=0 Eric Dumazet
2009-03-11 13:47 ` David Miller
2009-03-11 15:00   ` Eric Dumazet
2009-03-11 16:24     ` David Miller [this message]
2009-03-12  7:26   ` Ilpo Järvinen
2009-03-13 21:25     ` David Miller
2009-03-14  8:22       ` Ilpo Järvinen
2009-03-14  9:31         ` Eric Dumazet

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