From owner-freebsd-net@FreeBSD.ORG Wed Jun 20 10:36:12 2007 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 8450816A46C for ; Wed, 20 Jun 2007 10:36:12 +0000 (UTC) (envelope-from dave@dogwood.com) Received: from ug-out-1314.google.com (ug-out-1314.google.com [66.249.92.171]) by mx1.freebsd.org (Postfix) with ESMTP id 2704013C480 for ; Wed, 20 Jun 2007 10:36:11 +0000 (UTC) (envelope-from dave@dogwood.com) Received: by ug-out-1314.google.com with SMTP id u2so344205uge for ; Wed, 20 Jun 2007 03:36:11 -0700 (PDT) Received: by 10.82.156.12 with SMTP id d12mr1134121bue.1182335770702; Wed, 20 Jun 2007 03:36:10 -0700 (PDT) Received: by 10.82.185.10 with HTTP; Wed, 20 Jun 2007 03:36:10 -0700 (PDT) Message-ID: <4ab61a80706200336l49f16764t1d95c61f0dd323e5@mail.gmail.com> Date: Wed, 20 Jun 2007 00:36:10 -1000 From: "David Cornejo" To: "Bjoern A. Zeeb" In-Reply-To: <20070620100441.E98813@maildrop.int.zabbadoz.net> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <4678896b.1cef600a.1a79.7312@mx.google.com> <20070620100441.E98813@maildrop.int.zabbadoz.net> Cc: freebsd-net@freebsd.org Subject: Re: soekris/sis tx checksum problems X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 20 Jun 2007 10:36:12 -0000 the remote machine sees bad checksums - netstat indicates that received packets are being discarded because of bad checksums. -txcsum has no effect, I don't think (at least mine) sis support offloading checksums - the only if flags seem to be VLAN_MTU dave c On 6/20/07, Bjoern A. Zeeb wrote: > On Tue, 19 Jun 2007, David Cornejo wrote: > > Hi, > > > I am using CURRENT on a Soekris 4801 (sis ethernet). With a recent kernel > > all TCP packets sent via sis0 have a bad checksum. Other systems using > other > > interface types (though I don't have a broad selection to test) don't seem > to > > suffer from this problem. > > how do you see the bad checksum? Are you running tcpdump on that sis > interface or did you have "invalid packets" on the remote machine? > > If it's the former that's because of hardware checksumming and you > should be able to ignore it. > > You can try > ifconfig sis0 -txcsum > and tcpdump would be fine again but the soekris cpu itself would > compute the checksum then. > > > /bz > > -- > Bjoern A. Zeeb bzeeb at Zabbadoz dot NeT > Software is harder than hardware so better get it right the first time. >