How to handle multiple SSIDs with the same BSS

Marcel Holtmann marcel at holtmann.org
Wed Dec 23 15:35:56 EST 2009


Hi Jouni,

> > BSS 00:1a:a1:53:50:a0 (on wlan0)
> > 	SSID: Private
> 
> > BSS 00:1a:a1:53:50:a0 (on wlan0)
> > 	SSID: Public
> 
> > When using the wpa_supplicant D-Bus interface, every BSS can only be
> > listed once and so we either see "Private" or "Public", but never
> > actually both of them. How should this be handled.
> 
> I wasn't aware that there is this kind of limitation in the D-Bus
> interface. It is clearly broken if it cannot include both of those
> networks.

from what I have read so far while going through the code, it is not
possible. The BSSID is used as unique path in D-Bus terms and because of
that there is no way both networks could be listed at the same time.

Actually this cause some funny behavior when trying to scan for those
SSIDs. Especially if they are hidden and you give both of them.

> > Also looking into the register_bss callbacks, you only get the BSS
> > address and not the set of IE.
> 
> I don't know how this mechanism is supposed to be used, but there needs
> to be a way for fetching more information about the BSS and BSSID by
> itself is not a sufficient key for identifying which BSS is being
> queried for (need to have BSSID,SSID pair or some other internally
> generated identifier which can be guaranteed to be unique).

Does wpa_supplicant already generate such unique BSS based identifier
somewhere internally? If not, it might make sense to do so.

Regards

Marcel




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