From owner-freebsd-questions@FreeBSD.ORG Mon Apr 28 17:45:06 2008 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 95CFB106564A; Mon, 28 Apr 2008 17:45:06 +0000 (UTC) (envelope-from tom@tomjudge.com) Received: from s200aog17.obsmtp.com (s200aog17.obsmtp.com [207.126.144.131]) by mx1.freebsd.org (Postfix) with SMTP id 8FA038FC21; Mon, 28 Apr 2008 17:45:05 +0000 (UTC) (envelope-from tom@tomjudge.com) Received: from source ([63.174.175.251]) by eu1sys200aob017.postini.com ([207.126.147.11]) with SMTP; Mon, 28 Apr 2008 17:45:04 UTC Received: from [172.17.2.235] (unknown [172.17.2.235]) by bbbx3.usdmm.com (Postfix) with ESMTP id C5109B8E1; Mon, 28 Apr 2008 17:20:44 +0000 (UTC) Message-ID: <48160770.2080509@tomjudge.com> Date: Mon, 28 Apr 2008 12:20:48 -0500 From: Tom Judge User-Agent: Thunderbird 2.0.0.12 (X11/20080227) MIME-Version: 1.0 To: Mr Y References: <20def4870804280859g3c18eae0x1af9e97ae8776916@mail.gmail.com> In-Reply-To: <20def4870804280859g3c18eae0x1af9e97ae8776916@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-net@freebsd.org, freebsd-questions@freebsd.org Subject: Re: OS throws away large packets X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 28 Apr 2008 17:45:06 -0000 Mr Y wrote: > Hi all, > > I'm trying to implement Large Recieve Offload for an Ethernet driver on > FreeBSD 6.3, but all my >MTU packets are being thrown by the OS. > I'm using mbuf chains in this imlpementation, each mbuf is a cluster of > MCLBYTES bytes. They are linked by the m_next pointer. > The first packet being thrown away is 2945 bytes long. Wireshark shows the > packet that is being passed to the OS is correct. > > Do I need to set some OS parameter to make it recieve mbuf chains? > > Please help. > Hi Yony, I seem to remember some discussion about this list last year see the following threads: http://lists.freebsd.org/pipermail/freebsd-net/2007-September/015250.html http://lists.freebsd.org/pipermail/freebsd-net/2007-September/015350.html From my limited reading of these threads just now and possibly bad memory. It would seem that the MRU to MTU relationship is defined in the nic driver rather than enforced further up the stack or at least that seamed to be the case with the bce driver. Hope this is helpful, Tom