[PATCH] wpa_supplicant: Add support for pregenerated MAC

[Andrzej Ostruszka]

My apologies Volker for not getting back to you earlier but somehow
I did not receive your e-mail.  I've just noticed now in patchwork that
you actually commented on this patch so I'll copy paste your question
below and try to answer.

> does this fix the problem that the user privacy setting will change the
> device-MAC address all the time? or what does it do in detail?

If you consider changing MAC as a problem then this actually might
aggravate it (or resolve - you would have to be more specific in your
question).

The context of this patch is that in Chrome OS we are adding MAC address
randomization and instead of changing MAC ourselves we have decided to
use WPA supplicant support for that and enhance it a bit.

Previously supplicant supported only completely random MAC so when you
are reconnecting to the same network the MAC will change.  This might be
OK for open/public networks but does not work well for cases where
stable IP/MAC is desired.  So the proposal is to add another 'mac_addr'
policy value with which one would be able to provide "stable" MAC to be
used for given network.

Concrete implementation we are working on right now is that 'shill'
(Chrome OS "network manager") will generate random MAC for given network
and provide it to supplicant over DBus via:

  { mac_addr: 3, mac_value:"AA:BB:CC:XX:YY:ZZ" }

arguments of AddNetwork method and for this network this MAC
will be used (until device reset, or the user decides to change the MAC
policy e.g. to not randomize at all).

Hope this answers your question

With regards
Andrzej