From owner-freebsd-net@FreeBSD.ORG Tue Dec 19 14:42:06 2006 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 08ECA16A407; Tue, 19 Dec 2006 14:42:06 +0000 (UTC) (envelope-from rrs@cisco.com) Received: from sj-iport-2.cisco.com (sj-iport-2-in.cisco.com [171.71.176.71]) by mx1.FreeBSD.org (Postfix) with ESMTP id 6BB5E43C9F; Tue, 19 Dec 2006 14:38:53 +0000 (GMT) (envelope-from rrs@cisco.com) Received: from sj-dkim-3.cisco.com ([171.71.179.195]) by sj-iport-2.cisco.com with ESMTP; 19 Dec 2006 05:26:49 -0800 X-IronPort-AV: i="4.12,187,1165219200"; d="scan'208"; a="352762672:sNHT46126388" Received: from sj-core-2.cisco.com (sj-core-2.cisco.com [171.71.177.254]) by sj-dkim-3.cisco.com (8.12.11/8.12.11) with ESMTP id kBJDQn3D020028; Tue, 19 Dec 2006 05:26:49 -0800 Received: from xbh-sjc-231.amer.cisco.com (xbh-sjc-231.cisco.com [128.107.191.100]) by sj-core-2.cisco.com (8.12.10/8.12.6) with ESMTP id kBJDQnZg010496; Tue, 19 Dec 2006 05:26:49 -0800 (PST) Received: from xfe-sjc-212.amer.cisco.com ([171.70.151.187]) by xbh-sjc-231.amer.cisco.com with Microsoft SMTPSVC(6.0.3790.1830); Tue, 19 Dec 2006 05:26:49 -0800 Received: from [127.0.0.1] ([171.68.225.134]) by xfe-sjc-212.amer.cisco.com with Microsoft SMTPSVC(6.0.3790.1830); Tue, 19 Dec 2006 05:26:49 -0800 Message-ID: <4587E869.90108@cisco.com> Date: Tue, 19 Dec 2006 08:26:01 -0500 From: Randall Stewart User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20050920 X-Accept-Language: en-us, en MIME-Version: 1.0 To: "Bruce M. Simpson" References: <5628d8010612160452y5c562757h8ef8ed0776c5525d@mail.gmail.com> <458745F8.4090707@FreeBSD.org> In-Reply-To: <458745F8.4090707@FreeBSD.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 19 Dec 2006 13:26:49.0136 (UTC) FILETIME=[56693300:01C72371] DKIM-Signature: v=0.5; a=rsa-sha256; q=dns/txt; l=1785; t=1166534809; x=1167398809; c=relaxed/simple; s=sjdkim3002; h=Content-Type:From:Subject:Content-Transfer-Encoding:MIME-Version; d=cisco.com; i=rrs@cisco.com; z=From:=20Randall=20Stewart=20 |Subject:=20Re=3A=20UDP=20lite=20for=20FreeBSD |Sender:=20; bh=dw9wbid97Sp65zOFUxlAm1JU5BW1i4VfQBrZgg0tZGI=; b=gMs6htZU6VS6gNQ6s+P6e/8OCCKcxlQSdLzbjGN6EwdLNRiNaiACP1FACrrO0MpvjGhFslp3 WLvi0XNoFIfi5M2zCVzRxC0PZzGON79L4PPLoPbJLmBFlmdSh1BB9qgB; Authentication-Results: sj-dkim-3; header.From=rrs@cisco.com; dkim=pass (sig from cisco.com/sjdkim3002 verified; ); Cc: freebsd-net@freebsd.org, dave jones Subject: Re: UDP lite for FreeBSD 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: Tue, 19 Dec 2006 14:42:06 -0000 Bruce M. Simpson wrote: > dave jones wrote: > >> Hi, >> >> Is anyone working on implementing UDP lite in FreeBSD? If not, >> I'd like to work on it. > > Nope. I just skimmed the RFC and it sounds like a bit of a hack, though > I am sure it can be done cleanly in the source tree without unnecessary > code duplication or interference at the user-kernel boundary. > > I look forward to seeing patches for this. It would be interesting to > see if hardware checksum offloading can be taught to do it, cleanly, > though I imagine that is something much further down the line. > > Regards, > BMS > > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" > Bruce: I have always thought of it as a bit of a hack as well... and there is one really big problem with it.. It has no value unless you can tell your network-interface card to deliver damaged packets. I don't know if some cards have this option now or not.. nor if an API in any driver exists for it... without this you will find very very few packets that are "damaged" that do get through.. since generally the link layer checksum is a MUCH better CRC vs the very weak IP/UDP checksum :-0 If you get the driver mods.. then codecs like (... if my grey cells remember right..) AMR will be able to use the information.. of course that assumes you have something that can do the AMR codec... not sure what media uses this :-) There may be other codecs as well now too... I don't keep up with that side of the IETF :-) R -- Randall Stewart NSSTG - Cisco Systems Inc. 803-345-0369 803-317-4952 (cell)