From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH net-next] tcp: be more strict before accepting ECN negociation Date: Fri, 04 May 2012 22:49:06 +0200 Message-ID: <1336164546.3752.460.camel@edumazet-glaptop> References: <1336144442.3752.348.camel@edumazet-glaptop> <4FA41B5B.5080103@hp.com> <1336155815.3752.365.camel@edumazet-glaptop> <4FA42491.2020104@hp.com> <1336158359.3752.382.camel@edumazet-glaptop> <4FA43A03.4090707@hp.com> <4FA43DCE.8040901@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: David Miller , netdev , Perry Lorier , Matt Mathis , Yuchung Cheng , Neal Cardwell , Tom Herbert , Wilmer van der Gaast , Dave =?ISO-8859-1?Q?T=E4ht?= , Ankur Jain To: Rick Jones Return-path: Received: from mail-wi0-f178.google.com ([209.85.212.178]:42462 "EHLO mail-wi0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932896Ab2EDUtN (ORCPT ); Fri, 4 May 2012 16:49:13 -0400 Received: by wibhr7 with SMTP id hr7so1737876wib.1 for ; Fri, 04 May 2012 13:49:12 -0700 (PDT) In-Reply-To: <4FA43DCE.8040901@hp.com> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 2012-05-04 at 13:36 -0700, Rick Jones wrote: > On 05/04/2012 01:20 PM, Rick Jones wrote: > > True, I'm looking at more than the ECN bits, but in the 90 minutes the > > tcpdump has been running there have been no packets with the any of the > > 8 bits at ip[1] being 1 anyway :) Netperf.org doesn't get a massive > > quantity of traffic. It may go the entire week-end or longer without > > seeing such a packet. > > I see fate is working as intended, or someone decided to try to feed me > my words :) for within 6 minutes of my sending the above I got: > > 13:26:16.866007 IP (tos 0x3,CE, ttl 41, id 28850, offset 0, flags [DF], > proto TCP (6), length 64) > somesystemin.de.55363 > www.netperf.org.www: Flags [S], cksum > 0x4cfc (correct), seq 304457158, win 65535, options [mss 1460,nop,wscale > 3,nop,nop,TS val 288116308 ecr 0,sackOK,eol], length 0 > 13:26:17.831880 IP (tos 0x3,CE, ttl 41, id 6911, offset 0, flags [DF], > proto TCP (6), length 64) > somesystemin.de.55367 > www.netperf.org.www: Flags [S], cksum > 0x17aa (correct), seq 586073737, win 65535, options [mss 1460,nop,wscale > 3,nop,nop,TS val 288117270 ecr 0,sackOK,eol], length 0 > 13:26:17.831929 IP (tos 0x3,CE, ttl 41, id 28924, offset 0, flags [DF], > proto TCP (6), length 64) > somesystemin.de.55368 > www.netperf.org.www: Flags [S], cksum > 0x07cc (correct), seq 1513398047, win 65535, options [mss > 1460,nop,wscale 3,nop,nop,TS val 288117271 ecr 0,sackOK,eol], length 0 > 13:26:17.831952 IP (tos 0x3,CE, ttl 41, id 2494, offset 0, flags [DF], > proto TCP (6), length 64) > somesystemin.de.55366 > www.netperf.org.www: Flags [S], cksum > 0x75f4 (correct), seq 1153058420, win 65535, options [mss > 1460,nop,wscale 3,nop,nop,TS val 288117270 ecr 0,sackOK,eol], length 0 > 13:26:17.832177 IP (tos 0x3,CE, ttl 41, id 6854, offset 0, flags [DF], > proto TCP (6), length 64) > somesystemin.de.55365 > www.netperf.org.www: Flags [S], cksum > 0xfca0 (correct), seq 2332522875, win 65535, options [mss > 1460,nop,wscale 3,nop,nop,TS val 288117270 ecr 0,sackOK,eol], length 0 > 13:26:17.832239 IP (tos 0x3,CE, ttl 41, id 64733, offset 0, flags [DF], > proto TCP (6), length 64) > somesystemin.de.55364 > www.netperf.org.www: Flags [S], cksum > 0x7414 (correct), seq 1544827132, win 65535, options [mss > 1460,nop,wscale 3,nop,nop,TS val 288117270 ecr 0,sackOK,eol], length 0 > 13:26:38.649126 IP (tos 0x3,CE, ttl 41, id 9860, offset 0, flags [DF], > proto TCP (6), length 64) > somesystemin.de.55369 > www.netperf.org.www: Flags [S], cksum > 0x6270 (correct), seq 683091230, win 65535, options [mss 1460,nop,wscale > 3,nop,nop,TS val 288137968 ecr 0,sackOK,eol], length 0 > 13:26:39.417589 IP (tos 0x3,CE, ttl 41, id 13478, offset 0, flags [DF], > proto TCP (6), length 64) > somesystemin.de.55370 > www.netperf.org.www: Flags [S], cksum > 0x2862 (correct), seq 3168323595, win 65535, options [mss > 1460,nop,wscale 3,nop,nop,TS val 288138734 ecr 0,sackOK,eol], length 0 > > rick Interesting indeed ;) Did you check if it was spoofed ? (did the 3WHS really completed)