From owner-p4-projects@FreeBSD.ORG Thu Dec 7 16:38:47 2006 Return-Path: X-Original-To: p4-projects@freebsd.org Delivered-To: p4-projects@freebsd.org Received: by hub.freebsd.org (Postfix, from userid 32767) id 049F916A5C5; Thu, 7 Dec 2006 16:38:47 +0000 (UTC) X-Original-To: perforce@freebsd.org Delivered-To: perforce@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id D2A0216A5B9; Thu, 7 Dec 2006 16:38:46 +0000 (UTC) (envelope-from ru@rambler-co.ru) Received: from relay0.rambler.ru (relay0.rambler.ru [81.19.66.187]) by mx1.FreeBSD.org (Postfix) with ESMTP id 78DCB43CBB; Thu, 7 Dec 2006 16:36:48 +0000 (GMT) (envelope-from ru@rambler-co.ru) Received: from relay0.rambler.ru (localhost [127.0.0.1]) by relay0.rambler.ru (Postfix) with ESMTP id ADB036640; Thu, 7 Dec 2006 19:37:33 +0300 (MSK) Received: from edoofus.park.rambler.ru (unknown [81.19.65.108]) by relay0.rambler.ru (Postfix) with ESMTP id 8C3C86542; Thu, 7 Dec 2006 19:37:33 +0300 (MSK) Received: (from ru@localhost) by edoofus.park.rambler.ru (8.13.8/8.13.8) id kB7GbXNg039456; Thu, 7 Dec 2006 19:37:33 +0300 (MSK) (envelope-from ru) Date: Thu, 7 Dec 2006 19:37:33 +0300 From: Ruslan Ermilov To: Robert Watson Message-ID: <20061207163733.GC39204@rambler-co.ru> References: <200612062319.kB6NJgsq031755@repoman.freebsd.org> <20061207110225.GU32700@FreeBSD.org> <4578070A.2030609@freebsd.org> <20061207142254.GA1195@tin.it> <20061207161434.O50906@fledge.watson.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="C1iGAkRnbeBonpVg" Content-Disposition: inline In-Reply-To: <20061207161434.O50906@fledge.watson.org> User-Agent: Mutt/1.5.13 (2006-08-11) X-Virus-Scanned: No virus found Cc: Perforce Change Reviews , Gleb Smirnoff , Andre Oppermann , Paolo Pisati Subject: Re: PERFORCE change 111230 for review X-BeenThere: p4-projects@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: p4 projects tree changes List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 07 Dec 2006 16:38:47 -0000 --C1iGAkRnbeBonpVg Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Dec 07, 2006 at 04:16:41PM +0000, Robert Watson wrote: > On Thu, 7 Dec 2006, Paolo Pisati wrote: >=20 > >Then, after a discussion on irc, pull the plug on any present (and futur= e)=20 > >hackery & half-baked solution, and declare in kernel libalias incompatib= le=20 > >with tso. >=20 > This seems silly -- why is it not compatible? Perhaps I misunderstand, b= ut=20 > I thought TSO passed down valid TCP/IP packets, they just happen to be=20 > really long, and will be post-processed by the hardware into a series of= =20 > shorter segments with the same header properties. Imagine the ethernet= =20 > device as a "router" that's performing TCP fragmentation for you, rather= =20 > than IP fragmentation. >=20 It's a limitation of the current libalias code which grew up on top of userland version -- it doesn't currently know how to traverse mbufs, and instead requires a contiguous piece of (packet) data to do its job. : #ifdef _KERNEL : /* : * m_megapullup() function is a big hack (only used in ng_nat and ipfw+na= t). : * : * It allocates an mbuf with cluster and copies the whole : * chain into cluster, so that it is all contigous and the : * whole packet can be accessed via char pointer. : * This is required, because libalias doesn't have idea : * about mbufs. : *=20 : * On success, m_megapullup returns an mbuf with cluster : * containing the input packet, on failure NULL. : * In both cases, the input packet is consumed. : */ Cheers, --=20 Ruslan Ermilov ru@FreeBSD.org FreeBSD committer --C1iGAkRnbeBonpVg Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (FreeBSD) iD8DBQFFeENNqRfpzJluFF4RAgjZAJ9KK4I+XjXBUHw/mRI/AwsSk2DjKACcCTAe 1NPsrs9XfJsrFs0PmjOaPGU= =j54o -----END PGP SIGNATURE----- --C1iGAkRnbeBonpVg--