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

Jouni Malinen j
Sun Dec 14 08:03:11 PST 2014

On Thu, Dec 04, 2014 at 11:41:45PM +0530, Avinash Patil wrote:
> This patch adds dbus getter method for nl80211 iftype.
> This is required by certain applications which intend to start
> AP operations only if current interface type is AP.
> Getter method for capabilities cannot be used for this purpose as
> this enumarates all the supported interface types.

This is exposing an internal nl80211 specific debug string
(nl80211_iftype_str() output) through a D-Bus interface that is supposed
to be independent of the used driver interface.

I don't think I fully understand the use case where this would really be
needed in this scope. The use case you described previously was to
figure out whether an AP mode can be started and that determination is
somehow made by "certain applications". This seems to imply that such
applications would need to be aware of the constraint of AP being usable
only if the current interface type is already AP.. That does not sound
reasonable expectation to me.

In other words, I cannot really understand how this is supposed to work
cleanly. Either there are some other use cases that I have not yet
understood or this is way too more complex design for something as
simple as indicating whether an AP mode operation could be supported on
an interface.

> Patch also adds notification handlers for interface type change
> events.

That looks pretty complex. What is that needed for? I'd rather limit
this type of change to as small number of locations as possible rather
than expecting all places touching association, deauthentication,
disassociation, etc. to be aware of this special notification event.

Jouni Malinen                                            PGP id EFC895FA

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