From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753154AbbIPMrU (ORCPT ); Wed, 16 Sep 2015 08:47:20 -0400 Received: from metis.ext.pengutronix.de ([92.198.50.35]:37657 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753041AbbIPMrS (ORCPT ); Wed, 16 Sep 2015 08:47:18 -0400 Date: Wed, 16 Sep 2015 14:47:13 +0200 From: Michael Grzeschik To: David Miller Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@pengutronix.de Subject: Re: [PATCH] ARCNET: fix hard_header_len limit Message-ID: <20150916124713.GA18173@pengutronix.de> References: <20150805153451.GB20781@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150805153451.GB20781@pengutronix.de> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 14:41:23 up 1 day, 8:00, 52 users, load average: 0.27, 0.16, 0.15 User-Agent: Mutt/1.5.21 (2010-09-15) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: mgr@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 05, 2015 at 05:34:51PM +0200, Michael Grzeschik wrote: > On Thu, Jul 30, 2015 at 11:16:36AM -0700, David Miller wrote: > > From: Michael Grzeschik > > Date: Thu, 30 Jul 2015 15:34:36 +0200 > > > > > The commit <9c7077622dd9> ("packet: make packet_snd fail on len smaller > > > than l2 header") adds the check for minimum packet length of the used l2. > > > For arcnet the hardware header length is not the complete archdr which > > > includes hard + soft header. This patch changes the length to > > > sizeof(arc_hardware). > > > > > > Signed-off-by: Michael Grzeschik > > > > The hard header len is used for other purposes as well, are you sure > > those don't get broken by this change? > > Its meaning is to represent the amount of the hardware (link layer) > data of one packet. > > Which other purposes do you mean? > Can you point to some code? > > > Code assumes that if the data at the SKB mac pointer is taken, for > > dev->hard_header_len bytes, that is exactly the link layer header. > > And that this can be used to compare two MAC headers, copy the > > MAC header from one packet to another, etc. > > The link layer size of arcnet is 4 bytes long. 1 byte source, 1 byte > dest and two offset bytes. As described by struct arc_hardware in > if_arcnet.h . The above condition is fulfilled when the mac pointer > is 0. > > The following pending bytes of struct archdr have a variable meaning > depending of the used protocol and are represented by an union. > (network layer) > > In the case of raw packets, the payload comes immediately after the > hard_header. > Ping! I have the cleanup patches from Joe Perches and several ARCNET patches on top, waiting to be posted on the list. What is your Opinion to my Maintainer Request I send some weeks ago? Michael -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |