[PATCH V2 21/23] nl80211: verify P2P-GO/CLIENT address with all interface addresses

[Jouni Malinen]

On Sun, Jun 30, 2013 at 10:43:46PM +0200, Arend van Spriel wrote:
> Good point. The P2P interface address and P2P device address only
> need to be different if one would want to do P2P management and have
> a group connection concurrently (correct me if I am wrong here,
> maybe it is a restriction for brcm firmware only) so the check seems
> a bit too restrictive.

There is no such restriction in the P2P protocol specification. I've
been trying to figure out why Broadcom went with such design, but
anyway, if that is indeed a restriction in the firmware, it could be
useful to provide a driver capability flag to allow wpa_supplicant to
determine which rule to use.. I would use either the non-P2P station
interface MAC address or alternatively, the first P2P Interface Address
(which should be that non-P2P station interface MAC address with the
locally administered bit set to 1 or another globally unique MAC
address) as the P2P Device Address.

I would really like to avoid confusion and unjustifiable requests in
this area where that existing design could be used to claim that other
drivers need to behave similarly when there is no real technical reason
for doing that. In other words, drivers should be able to select
whichever P2P spec compliant mechanism they need. wpa_supplicant should
hide these internal details from anything above it (and that can now
finally be the case with the global control interface for P2P
operations).

An earlier thread  seemed to already imply that some people may believe
that this new dedicated P2P_DEVICE is needed for some concurrent P2P
operations which is simply not the case; it just adds another option for
internal driver/firmware/hardware design which should not add or remove
any functionality and the only externally observable difference should
be in MAC addresses potentially being different (but even those could be
assigned using the same style between P2P_DEVICE and p2p-mgmt-netdev).

-- 
Jouni Malinen                                            PGP id EFC895FA