wpa-supplicant questions

Jouni Malinen jkmaline at cc.hut.fi
Thu Sep 8 03:51:36 EDT 2005


On Thu, Sep 08, 2005 at 10:46:21AM +0300, Bar, Eitan wrote:

> Regarding Pre-authentication, a few more questions:
> 
> 1. When the driver generates the EVENT_PMKID_CANDIDATE event, this is
> done per BSSID, right? Meaning the driver should parse scan results, for
> APs with same SSID, and generate EVENT_PMKID_CANDIDATE event per AP?

Yes.

> 2. Does the driver have to wait for a SET-PMKID (pre-auth complete) to
> be called before issuing a new EVENT_PMKID_CANDIDATE event? Or can it
> send a few events as a bunch and then wait for all results?

No, driver does not need to wait. EVENT_PMKID_CANDIDATE events can be
sent whenever there is new information about candidates.

> 3. Can the driver called EVENT_PMKID_CANDIDATE with current (connected)
> BSSID?

Yes. wpa_supplicant will automatically skip the BSSIDs for which it
already has an PMKSA entry (and will call set PMKID for these to update
the driver).

> 4. Regarding pre-auth failure, I will probably modify the event handler
> to start a timeout per BSSID and then notify the driver of failure. I
> currently need this since it is a driver requirement (host CPU must be
> informed of end of pre-authentication process so it would be able to
> power-down if idle).

I'm not sure why this would be needed since pre-authentication is just
using normal data frames and can use power saving.. Anyway, if this is
indeed seen as useful event and if you are able to release these changes
under GPL2+BSD, please submit the patch to be included in future
wpa_supplicant versions.

> Besides timeout of a request, is there a specific fail message sent by
> APs in case of pre-auth failure?

APs are not really involved in pre-authentication. Authentication server
will likely send EAP-Failure message to the supplicant, though, in case
it rejects authentication.

-- 
Jouni Malinen                                            PGP id EFC895FA



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