[Patch v3] supplicant: add dbus getter method for nl80211 iftype

Jouni Malinen j
Mon Dec 22 02:42:21 PST 2014

On Mon, Dec 22, 2014 at 03:11:16PM +0530, Avinash Patil wrote:
> Implementations may vary from vendor to vendor. One vendor implements it
> this way does not mean all should follow the same, isnt it?
> Interface capabilities/combination advertised by wiphy are per hardware
> device and there is no restriction on how these this combination can be
> supported. Single hardware device can be emulated to support multiple
> virtual interfaces with different capabilities and that's what we intend to
> do.
> So when wiphy capabilities indicate support for AP interface, it does not
> mean we should expect very first interface to be of AP type.
> Driver can have multiple virtual interfaces and one of them would support
> AP operation. So having right to know interface type is something that is
> not expected??

That's a kernel side question (i.e., not really a topic for the hostap
mailing list, but linux-wireless). I agree that vendors can have
different designs in how what kind of combinations are supported.
However, you will need to make sure cfg80211 can advertise the
capabilities properly for your driver. It sounds like that is not the
case here now and until either cfg80211/nl80211 or the driver changes,
it sounds like it is premature to decide what, if anything, should
change in wpa_supplicant.

> Our current implementation cannot modify interface type(AP<=>STA) but still
> we are able to support simultaneous AP/STA operations using
> hostapd/wpa_supplicant.
> Connman expects to control both using wpa_supplicant and this is where we
> need to have support from supplicant to know interface type.

Doing this based on the _current interface type_ is clearly incorrect.
This needs to be done based on interface capabilities.

> Also about notification handlers, if you are not OK with it, I would
> completely remove notification handler related code.

I would remove _all_ of this patch and start from scratch making sure
that the driver can advertise its capabilities correctly. Once that is
done, it should be trivial to use either the already existing D-Bus
interface in wpa_supplicant (it does have flag indicating whether an
interface supports AP mode) or some minimal extensions to it to expose
whatever specific capabilities are needed with your driver.

Jouni Malinen                                            PGP id EFC895FA

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