From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Horman Subject: Re: [Lksctp-developers] [PATCH] SCTP: drop SACK if ctsn is not less than the next tsn of assoc Date: Wed, 1 Aug 2007 07:19:40 -0400 Message-ID: <20070801111939.GA7757@hmsreliant.homelinux.net> References: <18087.57737.908842.337891@zeus.sw.starentnetworks.com> <46AEBE2B.1060702@cn.fujitsu.com> <20070731113709.GA28333@hmsreliant.homelinux.net> <1185902894.8234.5.camel@localhost.localdomain> <46AFDC97.6080909@cn.fujitsu.com> <5BCC24EA-FACD-4B5D-BD1C-2DB11DEDB46D@lurchi.franken.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Wei Yongjun , Sridhar Samudrala , netdev@vger.kernel.org, lksctp-developers@lists.sourceforge.net To: Michael Tuexen Return-path: Received: from ra.tuxdriver.com ([70.61.120.52]:4555 "EHLO ra.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753687AbXHALU0 (ORCPT ); Wed, 1 Aug 2007 07:20:26 -0400 Content-Disposition: inline In-Reply-To: <5BCC24EA-FACD-4B5D-BD1C-2DB11DEDB46D@lurchi.franken.de> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Wed, Aug 01, 2007 at 11:01:21AM +0200, Michael Tuexen wrote: > Hi Wei, > > see my comments in-line. > > Best regards > Michael > > > >(*1) At this point ctsn_ack_point=0,next_tsn=2, ctsn=1, SACK is > >accept. > >After accept SACK, ctsn_ack_point=1. > >(*2) At this point ctsn_ack_point=1,next_tsn=6, ctsn=5,TSN_lt(ctsn, > >ctsn_ack_point) is ture, so accept SACK, and then ctsn_ack_point=5 > >(*3) At this point SACK is a dup SACK, ctsn_ack_point=5,next_tsn=6, > >ctsn=1000,TSN_lt(ctsn, ctsn_ack_point) is ture, so accept SACK, and > >then > >ctsn_ack_point=1000 > I would not consider it a duplicate SACK. RFC 4460, section 2.37.2 says > that an implementation SHOULD abort the association when receiving a > SACK acknowledging unsent data. So I would suggest to send an ABORT > chunk. +1. I didn't notice the ctsn value before. We can't safely accept that a peer pre-acks data we haven't sent. Too many security holes. Neil -- /*************************************************** *Neil Horman *Software Engineer *Red Hat, Inc. *nhorman@tuxdriver.com *gpg keyid: 1024D / 0x92A74FA1 *http://pgp.mit.edu ***************************************************/