Subject: Re: [PATCH net-next] sysfs: add entry to indicate network interfaces with random MAC address

From: Harald Hoyer <[email-masked]>
Date: Wed, 21 Jul 2010 08:47:36 +0200

On 07/21/2010 08:34 AM, David Miller wrote:
> From: Harald Hoyer<[email-masked]>
> Date: Wed, 21 Jul 2010 08:26:27 +0200
>
>> On 07/20/2010 11:20 PM, David Miller wrote:
>>> From: Stephen Hemminger<[email-masked]>
>>> 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
>
> So... why doesn't this work?

It works.. but the information, that the MAC is randomly generated would be 
valuable. So, for the non-random locally assigned MAC (with bit 1), we could 
easily make persistent rules based on the MAC, instead of completely ignoring 
them, like we do currently.