Virtual Interface for P2P operations

Jouni Malinen j at w1.fi
Fri Jul 22 13:57:11 EDT 2011


On Fri, Jul 22, 2011 at 09:51:24AM -0700, Henry Ptasinski wrote:
> On 07/22/2011 05:44 AM, Johannes Berg wrote:
> >wpa_supplicant calls this the WPA_IF_P2P_GROUP but I think the term "P2P device interface" would be more appropriate here.
> 
> Is this the P2P Device address or the P2P Interface address?  "P2P
> device interface" is going to be a problematic name I think.

There seems to be some misunderstanding here.. WPA_IF_P2P_GROUP is not
used as the separate P2P device interface (P2P Device Address); it is
used for a P2P group interface (P2P Interface Address) when
wpa_supplicant does not yet know what the eventual role will be. In
other words, it is used during group owner negotiation when the local GO
Intent is not 15. The interface needs to be added before the eventual
role is negotiated since the P2P Interface Address is allocated when
that netdev is added.

Anyway, wpa_supplicant does indeed have a concept of a dedicated P2P
device interface, but is indicated differently. The driver wrapper marks
a network interface in this way with the
WPA_DRIVER_FLAGS_P2P_DEDICATED_INTERFACE flag. Please note that the
hostap.git repository does not have an example of such a driver (well,
apart from driver_test.c), but there are out-of-tree driver wrappers
that use such mechanism and the actual P2P implementation in
wpa_supplicant for such design is included in hostap.git.

-- 
Jouni Malinen                                            PGP id EFC895FA


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