From owner-freebsd-net Sun Nov 12 18:52:28 2000 Delivered-To: freebsd-net@freebsd.org Received: from InterJet.dellroad.org (adsl-63-194-81-26.dsl.snfc21.pacbell.net [63.194.81.26]) by hub.freebsd.org (Postfix) with ESMTP id C068337B479; Sun, 12 Nov 2000 18:52:25 -0800 (PST) Received: from curve.dellroad.org (curve.dellroad.org [10.1.1.30]) by InterJet.dellroad.org (8.9.1a/8.9.1) with ESMTP id SAA95651; Sun, 12 Nov 2000 18:52:14 -0800 (PST) Received: (from archie@localhost) by curve.dellroad.org (8.11.0/8.11.0) id eAD2qED17117; Sun, 12 Nov 2000 18:52:14 -0800 (PST) (envelope-from archie) From: Archie Cobbs Message-Id: <200011130252.eAD2qED17117@curve.dellroad.org> Subject: Re: libalias: Incremental Update of Internet Checksum In-Reply-To: <20001108200359.A38693@sunbay.com> "from Ruslan Ermilov at Nov 8, 2000 08:03:59 pm" To: Ruslan Ermilov Date: Sun, 12 Nov 2000 18:52:13 -0800 (PST) Cc: net@FreeBSD.ORG, Charles Mott , Ari Suutari X-Mailer: ELM [version 2.4ME+ PL82 (25)] MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Ruslan Ermilov writes: > The DifferentialChecksum() function in libalias(3) is used > to efficiently recompute the checksum for altered packets. > Unfortunately, the implementation suffers from the problem > described in RFC 1624. I have implemented the replacement > for it, using the final formula [4] from the RFC. > > The attached C program demonstrates the problem as well as > the new implementation. > > Comments? Wow.. seems like a pretty important thing to fix. We should try to get this into 4.2 if possible. -Archie __________________________________________________________________________ Archie Cobbs * Packet Design * http://www.packetdesign.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message