Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752908AbaBQK3q (ORCPT ); Mon, 17 Feb 2014 05:29:46 -0500 Received: from smtp.citrix.com ([66.165.176.89]:54222 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751591AbaBQK3p (ORCPT ); Mon, 17 Feb 2014 05:29:45 -0500 X-IronPort-AV: E=Sophos;i="4.95,859,1384300800"; d="scan'208";a="103127274" Message-ID: <5301E496.40802@citrix.com> Date: Mon, 17 Feb 2014 10:29:42 +0000 From: David Vrabel User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.16) Gecko/20121215 Iceowl/1.0b1 Icedove/3.0.11 MIME-Version: 1.0 To: "Luis R. Rodriguez" CC: , Wei Liu , Ian Campbell , , "Luis R. Rodriguez" , , Paul Durrant , Subject: Re: [Xen-devel] [RFC v2 3/4] xen-netback: use a random MAC address References: <1392433180-16052-1-git-send-email-mcgrof@do-not-panic.com> <1392433180-16052-4-git-send-email-mcgrof@do-not-panic.com> In-Reply-To: <1392433180-16052-4-git-send-email-mcgrof@do-not-panic.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.80.2.76] X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15/02/14 02:59, Luis R. Rodriguez wrote: > From: "Luis R. Rodriguez" > > The purpose of using a static MAC address of FE:FF:FF:FF:FF:FF > was to prevent our backend interfaces from being used by the > bridge and nominating our interface as a root bridge. This was > possible given that the bridge code will use the lowest MAC > address for a port once a new interface gets added to the bridge. > The bridge code has a generic feature now to allow interfaces > to opt out from root bridge nominations, use that instead. [...] > --- a/drivers/net/xen-netback/interface.c > +++ b/drivers/net/xen-netback/interface.c > @@ -42,6 +42,8 @@ > #define XENVIF_QUEUE_LENGTH 32 > #define XENVIF_NAPI_WEIGHT 64 > > +static const u8 xen_oui[3] = { 0x00, 0x16, 0x3e }; You shouldn't use a vendor prefix with a random MAC address. You should set the locally administered bit and clear the multicast/unicast bit and randomize the remaining 46 bits. (If existing VIF scripts are doing something similar, they also need to be fixed.) David -- 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/