Issues with new D-Bus API

Jouni Malinen j
Thu Dec 31 02:22:36 PST 2009

On Thu, Dec 31, 2009 at 01:21:28AM -0800, Marcel Holtmann wrote:
> > Well, Dbus interface is just frontend. We can't expose variables which
> > are not available from wpa_supplicant (i.e. we can't get properties
> > values directly from driver). The other issue is that wpa_supplicant is
> > supposed to work with other drivers than nl80211.
> We might need to extend wpa_supplicant a bit. And if index != -1 then we
> can use it. Otherwise we won't. So it will be a Linux specific thing,
> but that is fine with me.

The ifname parameter is an identifier for the network device. It doesn't
need to be the interface name as a string, i.e., we could reserve
something like "ifindex:<ifindex>" as an identifier to indicate that the
value is indicating an ifindex instead of ifname and then just make
driver_nl80211.c handle this special case. This is similar to what is
already done in driver_ndis.c.

However, please keep in mind that while ifindex may be unique identifier
for the interface, it does have some potential issue like the case of
interface getting removed on suspend and returned on resume when it gets
a new ifindex. Similarly, unplugging and replugging a USB dongle would
result in a new ifindex. Currently, wpa_supplicant is able to handle
just cases of the interface disappearing and reappearing under the same
ifname (but different ifindex). If the driver wrapper were to be bound
to the ifindex, this kind of functionality would need new code somewhere
to remove the wpa_supplicant interface and add a new one with the new

Jouni Malinen                                            PGP id EFC895FA

More information about the Hostap mailing list