From owner-freebsd-arm@FreeBSD.ORG Wed Sep 12 02:13:55 2012 Return-Path: Delivered-To: freebsd-arm@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 87894106566C; Wed, 12 Sep 2012 02:13:55 +0000 (UTC) (envelope-from gnn@neville-neil.com) Received: from vps.hungerhost.com (vps.hungerhost.com [216.38.53.176]) by mx1.freebsd.org (Postfix) with ESMTP id 40E2F8FC14; Wed, 12 Sep 2012 02:13:55 +0000 (UTC) Received: from pool-96-250-5-62.nycmny.fios.verizon.net ([96.250.5.62]:58300 helo=new-host-3.home) by vps.hungerhost.com with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.77) (envelope-from ) id 1TBcSg-00056r-Dv; Tue, 11 Sep 2012 22:13:54 -0400 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 6.0 \(1486\)) From: George Neville-Neil In-Reply-To: <20120910064532.GP58312@funkthat.com> Date: Tue, 11 Sep 2012 22:13:53 -0400 Content-Transfer-Encoding: 7bit Message-Id: References: <20120910014813.GL58312@funkthat.com> <4448530B-7916-4642-BD32-6A96AD5DB22B@FreeBSD.org> <20120910064532.GP58312@funkthat.com> To: John-Mark Gurney X-Mailer: Apple Mail (2.1486) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - vps.hungerhost.com X-AntiAbuse: Original Domain - freebsd.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - neville-neil.com Cc: freebsd-arm@FreeBSD.org, Tim Kientzle Subject: Re: -current on BeableBone successful X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Porting FreeBSD to the StrongARM Processor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 12 Sep 2012 02:13:55 -0000 On Sep 10, 2012, at 02:45 , John-Mark Gurney wrote: > Tim Kientzle wrote this message on Sun, Sep 09, 2012 at 20:16 -0700: >>> Third is that I get this error: >>> ip length 328 disagrees with bytes received 330. >>> accepting packet with data after udp payload. >>> >>> This appeard to be from sbin/dhclient/packet.c... Not sure exactly why >>> we are returning a large packet to userland? >> >> I haven't seen this one. > > Looks like this is a BeagleBone issue. I haven't tracked it down, but > I did a tcpdump on the server (my other arm board), and the packet has > the correct length of 342 bytes to match the 328 ip length (plus 14 > bytes of ethernet header)... tcpdump on the BeagleBone receives a > 344 byte frame with a couple of stray bytes at the end of the frame... > > Could this be an miscalculation when we are copying around the frame > to deal the fact our IP stack can't deal w/ misaligned headers? Just > a thought.. > > Hmm... Just ran some experiments... > > ping -s sent received > 1 0x2b 0x3e > 10 0x34 0x3e > 18 0x3c 0x3e > 19 0x3d 0x3f > 20 0x3e 0x40 > 21 0x3f 0x41 > 99 0x8d 0x8f > 100 0x8e 0x90 > 101 0x8f 0x91 > 999 0x411 0x413 > 1000 0x412 0x414 > 1001 0x413 0x415 > > and 0x3e is 62, which is two short of the min frame length of 64... > > Hope this helps. My take is the following. The minimum packet is 60, not including the preamble or the CRC, so with a CRC it's 64. It might be that there is some alignment issue as well. The difference between all the sent/received is 2 bytes and that's consistent so either something isn't being stripped or there is an alignment issue all the way round. Best, George