Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030272AbVIBGLp (ORCPT ); Fri, 2 Sep 2005 02:11:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030266AbVIBGLp (ORCPT ); Fri, 2 Sep 2005 02:11:45 -0400 Received: from r-dd.iij4u.or.jp ([210.130.0.70]:12505 "EHLO r-dd.iij4u.or.jp") by vger.kernel.org with ESMTP id S1030248AbVIBGLo (ORCPT ); Fri, 2 Sep 2005 02:11:44 -0400 Date: Fri, 02 Sep 2005 15:11:32 +0900 (JST) Message-Id: <20050902.151132.15273184.Noritoshi@Demizu.ORG> From: Noritoshi Demizu To: Stephen Hemminger , Ion Badulescu , linux-kernel@vger.kernel.org, linux-net@vger.kernel.org Subject: Re: Possible BUG in IPv4 TCP window handling, all recent 2.4.x/2.6.x kernels In-Reply-To: <20050902.144537.35010282.Noritoshi@Demizu.ORG> References: <20050902.135138.38716488.Noritoshi@Demizu.ORG> <20050901222032.5cc649c0@localhost.localdomain> <20050902.144537.35010282.Noritoshi@Demizu.ORG> X-Mailer: Mew version 4.1 on Emacs 21 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1261 Lines: 27 > By the way, if tcpdump does not track the window scale option, the right > edge (ack + real win) does not change between the following two ACKs. > > > 11:34:54.337167 10.2.20.246.33060 > 10.2.224.182.8700: . ack 84402527 win 15340 (DF) > (259 ACKs are omitted here) > > 11:34:54.611769 10.2.20.246.33060 > 10.2.224.182.8700: . ack 84454467 win 2355 (DF) > > The first line is the 37th ACK and the second line is the 295th ACK. > > ACK#37: ack=84402527 win=15340 right_edge=84463887 (= ack + win * 4) > ACK#295: ack=84454467 win=2355 right_edge=84463887 (= ack + win * 4) > > And all ACKs later than ACK#295 has win=2355 (2355*4=9420). > > This may be a hint. But, sorry, I do not know the internal of Linux TCP. I think there is a possibility that some middle-box does something, for example, some middle-box between the two machines does kinda traffic-shaping by tweaking the TCP window size field. Regards, Noritoshi Demizu - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/