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    SubjectRe: [PATCH net-next] sysfs: add entry to indicate network interfaces with random MAC address
    On Wed, Jul 21, 2010 at 08:47:36AM +0200, Harald Hoyer wrote:
    > On 07/21/2010 08:34 AM, David Miller wrote:
    >> From: Harald Hoyer<harald@redhat.com>
    >> Date: Wed, 21 Jul 2010 08:26:27 +0200
    >>
    >>> 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
    >>
    >> 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.

    Agreed. The subtle difference between a locally assigned address that
    is persistent and one that is random would be helpful.



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