Subject: Re: SIOCSIWESSID + SIOCSIWAP behaviour

From: Jouni Malinen <[email-masked]>
Date: Mon, 15 May 2006 06:16:56 -0700

On Sun, May 14, 2006 at 11:29:38PM -0400, Dan Williams wrote:
> On Mon, 2006-05-15 at 00:29 +0100, Daniel Drake wrote:
> > When SIWESSID happens, softmac drops association/authentication with the 
> > current network and then starts a scan for the requested SSID. When 
> > found, softmac authenticates and associates to that network.

I don't think there is requirement for doing a new scan here if recent
scan results are available.

> > When SIWAP happens, softmac drops association/authentication with the 
> > current network and then starts a scan for the requested BSSID. When 
> > found, softmac authenticates and associates to that network.

Same here. Neither of these commands should drop IEEE 802.11
authentication. I would say that neither should drop association either
until a new association is available or it is clear that current
configuration does not allow association to be created. First case would
just report a new association (no disassociation reported) and second
case would report disassociation to user space.

> > Right now, wpa_supplicant does SIWESSID and SIWAP in quick succession, 
> > which causes softmac to associate twice, and that quickly confuses things.
> 
> (I don't really understand why wpa_supplicant uses SIWAP when a BSSID
> isn't specified in the config file, but...)

There are two different modes and what is being described here is
ap_scan=1, i.e., wpa_supplicant being responsible for requesting
scanning and selecting an AP. In this mode, it is actually assumed that
the driver does not do extra scans with SIWAP or SIWESSID.
wpa_supplicant is telling the driver which channel (SIOCSIWFREQ), SSID,
and BSSID to use.

In the other mode, ap_scan=2, wpa_supplicant is only configuring the
SSID and requesting the driver (or well, kernel side 802.11 management
code) to figure out which AP to use.

-- 
Jouni Malinen                                            PGP id EFC895FA