From owner-freebsd-current@FreeBSD.ORG Sun Dec 24 05:10:16 2006 Return-Path: X-Original-To: current@FreeBSD.org Delivered-To: freebsd-current@FreeBSD.ORG Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id C40D916A415; Sun, 24 Dec 2006 05:10:16 +0000 (UTC) (envelope-from kris@obsecurity.org) Received: from elvis.mu.org (elvis.mu.org [192.203.228.196]) by mx1.freebsd.org (Postfix) with ESMTP id AD0AC13C474; Sun, 24 Dec 2006 05:10:16 +0000 (UTC) (envelope-from kris@obsecurity.org) Received: from obsecurity.dyndns.org (elvis.mu.org [192.203.228.196]) by elvis.mu.org (Postfix) with ESMTP id 902911A3C1C; Sat, 23 Dec 2006 21:10:16 -0800 (PST) Received: by obsecurity.dyndns.org (Postfix, from userid 1000) id 7F464513F2; Sun, 24 Dec 2006 00:10:13 -0500 (EST) Date: Sun, 24 Dec 2006 00:10:13 -0500 From: Kris Kennaway To: Ruslan Ermilov Message-ID: <20061224051013.GA25197@xor.obsecurity.org> References: <20061217205249.GA73132@xor.obsecurity.org> <20061222080202.GB77429@rambler-co.ru> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="+HP7ph2BbKc20aGI" Content-Disposition: inline In-Reply-To: <20061222080202.GB77429@rambler-co.ru> User-Agent: Mutt/1.4.2.2i Cc: Andrew Pantyukhin , David Xu , current@FreeBSD.org, Kris Kennaway Subject: Re: vge(4) bad checksum X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 24 Dec 2006 05:10:16 -0000 --+HP7ph2BbKc20aGI Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Dec 22, 2006 at 11:02:02AM +0300, Ruslan Ermilov wrote: > Hi, >=20 > On Sun, Dec 17, 2006 at 03:52:49PM -0500, Kris Kennaway wrote: > > On Sun, Dec 17, 2006 at 11:46:24PM +0300, Andrew Pantyukhin wrote: > > > I'm not sure what it's all about, but with today's > > > current whatever goes out my vge interface (icmp/ > > > tcp/udp) has bad checksum: > >=20 > > This is a FAQ; it's probably using hardware checksum offloading. > >=20 > > Since the packet passed down to the NIC does not yet have the checksum > > computed, it looks to tcpdump like the checksum is incorrect. However > > if you look at the packet actually transmitted by the NIC > > (e.g. tcpdump on another host), you'll see that it has the correct > > checksum. > >=20 > Kris, you probably missed a commit by csjp@ where it was fixed. >=20 > : revision 1.220 > : date: 2006/11/18 23:17:22; author: csjp; state: Exp; lines: +40 -0 > : Currently, drivers that support hardware offload of VLAN tag > : processing are forced to toggle this functionality when the card > : is put in and out of promiscuous mode. The main reason for this > : is because the hardware strips the VLAN tag, making it impossible > : for the tag information to show up in network diagnostic tools like > : tcpdump(1). > : [...] That sounds like an unrelated issue (VLAN tagging, not checksum offloading). Kris --+HP7ph2BbKc20aGI Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (FreeBSD) iD8DBQFFjgu0Wry0BWjoQKURAjDlAKCUlnzxhgPtZM1hVmGzimXlfwx18QCg7U8R k6cpBk7hiETq5MJFQEvrY4Y= =VvHv -----END PGP SIGNATURE----- --+HP7ph2BbKc20aGI--