Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 28 Nov 2001 14:34:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 28 Nov 2001 14:34:01 -0500 Received: from [128.165.17.254] ([128.165.17.254]:48336 "EHLO balance.radtt.lanl.gov") by vger.kernel.org with ESMTP id ; Wed, 28 Nov 2001 14:33:46 -0500 Date: Wed, 28 Nov 2001 12:33:41 -0700 From: Eric Weigle To: Lars Brinkhoff Cc: linux-kernel@vger.kernel.org Subject: Re: Magic Lantern Message-ID: <20011128123341.K22767@lanl.gov> In-Reply-To: <20011128081305.I22767@lanl.gov> <85oflmvi8g.fsf@junk.nocrew.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <85oflmvi8g.fsf@junk.nocrew.org> User-Agent: Mutt/1.3.18i X-Eric-Unconspiracy: There ought to be a conspiracy X-Editor: Vim, http://www.vim.org Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 28, 2001 at 07:54:39PM +0100, Lars Brinkhoff wrote: > Eric Weigle writes: > > > > "Richard B. Johnson" writes: > > > > > Basically, a "tee" to capture all network packets and pass them > > > > > on to a filtering task without affecting normal network activity. > > > > The af_packet module can read and write raw ethernet frames. > > The af_packet module may also be fairly inefficient. If you need > > performance over, say, a gigabit link, you may have trouble. > > Are you (or anyone else) aware of any alternative? I'm sure it's just something silly that's hurt the performance of the af_packet module (perhaps already fixed, perhaps in my methodology :|) For the purposes of the work I was doing here (totally unrelated to this Magic Lantern BS, which I didn't even know what it was until after I posted the first response in this thread), I just needed to saturate a gigE link for testing. To do this I just used three boxes flooding UDP packets and that worked. As far as traffic collection goes (which is what I was testing), we went with another approach-- an optical tap to snarf off a copy of all the data on a link, and then a custom kernel I hacked up to do the work in the kernel itself (avoiding the kernel--user space copy and the stack entirely). This is not for the faint of heart. -Eric -- -------------------------------------------- Eric H. Weigle CCS-1, RADIANT team ehw@lanl.gov Los Alamos National Lab (505) 665-4937 http://home.lanl.gov/ehw/ -------------------------------------------- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/