From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: TCP-MD5 checksum failure on x86_64 SMP Date: Mon, 17 May 2010 07:03:49 +0200 Message-ID: <1274072629.2299.58.camel@edumazet-laptop> References: <1273085598.2367.233.camel@edumazet-laptop> <1273147586.2357.63.camel@edumazet-laptop> <20100506.220443.135536330.davem@davemloft.net> <1273210329.2222.42.camel@edumazet-laptop> <20100507101451.1b4286b7@nehalam> <1273252893.2261.84.camel@edumazet-laptop> <20100507103639.4f1a51fa@nehalam> <1273268446.2325.53.camel@edumazet-laptop> <1273504693.2221.17.camel@edumazet-laptop> <1273611036.2512.18.camel@edumazet-laptop> <1274042939.2299.27.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Stephen Hemminger , David Miller , "" , "" , netdev , Ilpo =?ISO-8859-1?Q?J=E4rvinen?= To: Bijay Singh Return-path: Received: from mail-ww0-f46.google.com ([74.125.82.46]:37745 "EHLO mail-ww0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751716Ab0EQFDz (ORCPT ); Mon, 17 May 2010 01:03:55 -0400 Received: by wwi17 with SMTP id 17so244012wwi.19 for ; Sun, 16 May 2010 22:03:53 -0700 (PDT) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Le lundi 17 mai 2010 =C3=A0 03:49 +0000, Bijay Singh a =C3=A9crit : > I am on quite an old kernel 2.6.27 and could not apply your patches. >=20 > Then i moved on to the kernel 2.6.32.11 however since then I have not= been able to bring up my card, this is something i need to fix before = i can test you fix. Working on that. >=20 Thanks again for the status report. I see bug is older than what I stated in my previous mail I could reproduce it in my lab and confirm following patch fixes it This is a stable candidate (2.6.27 kernels) Thanks [PATCH] tcp: tcp_synack_options() fix=20 Commit 33ad798c924b4a (tcp: options clean up) introduced a problem if MD5+SACK+timestamps were used in initial SYN message. Some stacks (old linux for example) try to negotiate MD5+SACK+TSTAMP sessions, but since 20 bytes of tcp options space are not enough to store all the bits needed, we chose to disable timestamps in this case. We send a SYN-ACK _without_ timestamp option, but socket has timestamps enabled and all further outgoing messages contain a TS block, all with the initial timestamp of the remote peer. =46ix is to really disable timestamps option for the whole session. Reported-by: Bijay Singh Signed-off-by: Eric Dumazet --- net/ipv4/tcp_output.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 0dda86e..b8bb226 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -667,7 +667,7 @@ static unsigned tcp_synack_options(struct sock *sk, u8 cookie_plus =3D (xvp !=3D NULL && !xvp->cookie_out_never) ? xvp->cookie_plus : 0; - bool doing_ts =3D ireq->tstamp_ok; + bool doing_ts; =20 #ifdef CONFIG_TCP_MD5SIG *md5 =3D tcp_rsk(req)->af_specific->md5_lookup(sk, req); @@ -680,11 +680,12 @@ static unsigned tcp_synack_options(struct sock *s= k, * rather than TS in order to fit in better with old, * buggy kernels, but that was deemed to be unnecessary. */ - doing_ts &=3D !ireq->sack_ok; + ireq->tstamp_ok &=3D !ireq->sack_ok; } #else *md5 =3D NULL; #endif + doing_ts =3D ireq->tstamp_ok; =20 /* We always send an MSS option. */ opts->mss =3D mss;