From owner-freebsd-net@FreeBSD.ORG Fri Sep 7 20:44:05 2007 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 2A2E116A418; Fri, 7 Sep 2007 20:44:05 +0000 (UTC) (envelope-from davidch@broadcom.com) Received: from mms2.broadcom.com (mms2.broadcom.com [216.31.210.18]) by mx1.freebsd.org (Postfix) with ESMTP id BD57E13C46C; Fri, 7 Sep 2007 20:44:04 +0000 (UTC) (envelope-from davidch@broadcom.com) Received: from [10.10.64.154] by mms2.broadcom.com with ESMTP (Broadcom SMTP Relay (Email Firewall v6.3.1)); Fri, 07 Sep 2007 13:43:49 -0700 X-Server-Uuid: A6C4E0AE-A7F0-449F-BAE7-7FA0D737AC76 Received: by mail-irva-10.broadcom.com (Postfix, from userid 47) id 93FAB2AF; Fri, 7 Sep 2007 13:43:49 -0700 (PDT) Received: from mail-irva-8.broadcom.com (mail-irva-8 [10.10.64.221]) by mail-irva-10.broadcom.com (Postfix) with ESMTP id 7F8472AE; Fri, 7 Sep 2007 13:43:49 -0700 (PDT) Received: from mail-irva-12.broadcom.com (mail-irva-12.broadcom.com [10.10.64.146]) by mail-irva-8.broadcom.com (MOS 3.7.5a-GA) with ESMTP id FQS13967; Fri, 7 Sep 2007 13:43:46 -0700 (PDT) Received: from NT-IRVA-0750.brcm.ad.broadcom.com ( nt-irva-0750.brcm.ad.broadcom.com [10.8.194.64]) by mail-irva-12.broadcom.com (Postfix) with ESMTP id BFF7E69CA3; Fri, 7 Sep 2007 13:43:46 -0700 (PDT) X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Date: Fri, 7 Sep 2007 13:43:43 -0700 Message-ID: <09BFF2FA5EAB4A45B6655E151BBDD903051CBF54@NT-IRVA-0750.brcm.ad.broadcom.com> In-Reply-To: <20070907194749.GD87451@elvis.mu.org> Thread-Topic: FreeBSD discarding received packets > MTU Thread-Index: AcfxiHLJkDK0BJCZSnqWy2939BvrPQAA92CA References: <46E0632D.8070200@elischer.org> <46E07E74.5020204@elischer.org> <09BFF2FA5EAB4A45B6655E151BBDD9030501D5C0@NT-IRVA-0750.brcm.ad.broadcom.com> <46E0A5DB.3080404@elischer.org> <09BFF2FA5EAB4A45B6655E151BBDD903051CBEB6@NT-IRVA-0750.brcm.ad.broadcom.com> <20070907194749.GD87451@elvis.mu.org> From: "David Christensen" To: "Alfred Perlstein" X-WSS-ID: 6AFF678F49W40562-01-01 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Cc: FreeBSD Net , Julian Elischer Subject: RE: FreeBSD discarding received packets > MTU 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: Fri, 07 Sep 2007 20:44:05 -0000 > > I'm not completely opposed to making such a change, but I don't want > > to make a default change in the driver's behavior that other people=20 > > may be depending upon (whether they are aware of it or not). A > > tunable driver value could be the answer but I'm not entirely sure > > how it would fare in the hardware at the high end of MTU=20 > values such=20 > > as 9000. >=20 > Dave: >=20 > Internet ettiquette demands being gracious in what you accept. > The default policy of FreeBSD is to accept such packets. > This is a really weird bug to track down. > Other drivers support it. >=20 > This isn't worth making a stand over, unless you're trying > to hold users of YOUR driver hostage. >=20 I'm just being cautious about making changes before I understand all of the implications. The driver's current behavior is supported by IEEE 802.3 specification (802.3-2005, 4.2.4.2.1) and is implemented in the same way for other operating systems that are very widely deployed (including Windows and Linux) without any reported problems. The existing bge driver which was developed for FreeBSD 10 years ago also operates this way, so all of my references for porting this driver happen to agree on the same implementation. Dave