Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932187Ab0GTLUu (ORCPT ); Tue, 20 Jul 2010 07:20:50 -0400 Received: from mail.solarflare.com ([216.237.3.220]:32697 "EHLO exchange.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932167Ab0GTLUs (ORCPT ); Tue, 20 Jul 2010 07:20:48 -0400 Subject: Re: [PATCH net-next] sysfs: add entry to indicate network interfaces with random MAC address From: Ben Hutchings To: Stefan Assmann Cc: netdev , Linux Kernel Mailing List , davem@davemloft.net, Andy Gospodarek , "Rose, Gregory V" , "Duyck, Alexander H" , Casey Leedom , Harald Hoyer In-Reply-To: <4C457F72.8090708@redhat.com> References: <4C457F72.8090708@redhat.com> Content-Type: text/plain Organization: Solarflare Communications Date: Tue, 20 Jul 2010 12:20:44 +0100 Message-Id: <1279624844.2110.3.camel@achroite.uk.solarflarecom.com> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1 (2.26.1-2.fc11) Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 20 Jul 2010 11:22:15.0430 (UTC) FILETIME=[CE76EA60:01CB27FD] X-TM-AS-Product-Ver: SMEX-8.0.0.1181-6.000.1038-17516.005 X-TM-AS-Result: No--18.261100-0.000000-31 X-TM-AS-User-Approved-Sender: Yes X-TM-AS-User-Blocked-Sender: No Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1927 Lines: 47 On Tue, 2010-07-20 at 12:50 +0200, Stefan Assmann wrote: > From: Stefan Assmann > > Reserve a bit in struct net_device to indicate whether an interface > generates its MAC address randomly, and expose the information via > sysfs. > May look like this: > /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0/net/eth0/ifrndmac > > By default the value of ifrndmac is 0. Any driver that generates the MAC > address randomly should return a value to 1. The name should incorporate 'address', not 'mac', for consistency with the generic 'address' attribute. What about devices that 'steal' MAC addresses from slave devices? Currently I believe udev has special cases for them but ideally these drivers would indicate explicitly that their addresses are not stable identifiers (even though they aren't random). [...] > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > index b626289..2ea0298 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h > @@ -845,6 +845,7 @@ struct net_device { > #define NETIF_F_FCOE_MTU (1 << 26) /* Supports max FCoE MTU, 2158 bytes*/ > #define NETIF_F_NTUPLE (1 << 27) /* N-tuple filters supported */ > #define NETIF_F_RXHASH (1 << 28) /* Receive hashing offload */ > +#define NETIF_F_RNDMAC (1 << 29) /* Interface with random MAC address */ [...] This is not really a feature, and we are running out of real feature bits. Can you find somewhere else to put this flag? Ben. -- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked. -- 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/