From mboxrd@z Thu Jan  1 00:00:00 1970
From: Harald Hoyer <harald@redhat.com>
Subject: Re: [PATCH net-next] sysfs: add entry to indicate network interfaces
 with random MAC address
Date: Wed, 21 Jul 2010 08:26:27 +0200
Message-ID: <4C469313.6010807@redhat.com>
References: <1279636194.2110.45.camel@achroite.uk.solarflarecom.com>	<20100720.131748.51255156.davem@davemloft.net>	<20100720141816.16f0a939@nehalam> <20100720.142045.32697196.davem@davemloft.net>
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Cc: shemminger@vyatta.com, bhutchings@solarflare.com,
	sassmann@redhat.com, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, gospo@redhat.com,
	gregory.v.rose@intel.com, alexander.h.duyck@intel.com,
	leedom@chelsio.com
To: David Miller <davem@davemloft.net>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <20100720.142045.32697196.davem@davemloft.net>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: netdev.vger.kernel.org

On 07/20/2010 11:20 PM, David Miller wrote:
> From: Stephen Hemminger<shemminger@vyatta.com>
> Date: Tue, 20 Jul 2010 14:18:16 -0700
>
>> No one mentioned that the first octet of an Ethernet address already
>> indicates "software generated" Ethernet address. Per the standard,
>> if bit 1 is set it means address is locally assigned.
>>
>> static inline bool is_locally_assigned_ether(const u8 *addr)
>> {
>> 	return (addr[0]&  0x2) != 0;
>> }
>
> W00t!
>
> Indeed, can udev just use that?  :-)

It already does:
see /lib/udev/rules.d/75-persistent-net-generator.rules