Re: intermittent eap authentication failure

["Chuck Crisler" <ccrisler@vgocom.com>]

It is the MAC80211 code. I am looking to find the exact code that 
re-associates. We are running an old kernel (2.6.31.6) but can't update 
right now.

Our app is a mobile video conferencing system (a robot). It is imperative 
that my connection to the network always be good. When you get  a session 
timeout from the AP there isn't any reason to do a scan. The MAC driver can 
send the association request and then notify the supplicant when it receives 
the assosication response. The supplicant can then handle the higher layer 
authentication. With the minor supplicant change that I included earler this 
works with all authentication schemes. However, I have removed the 2 lines 
that dealt with setting the EAP authentication to NULL. I think that they 
were causing the EAP problems. The result is that now I re-connect after a 
session timeout withint 0.75 seconds.

Another problem that I found is that sometimes (not often) the Cisco WLC was 
sending us a second deauthentication while we were still 'disconnected'. The 
MAC driver dutifully sent that to the supplicant which was busy trying to 
re-authenticate, again causing a mess. Now, I have changed the MAC driver to 
drop that second deauth message if we aren't connected. It works a lot 
better.

The response that Daniel Halperin made to Larry Finger concerning the reason 
code 4 (inactivity) isn't correct. That may be the intent but Cisco sends 
that reason code more often. I have received it withint 3 seconds of 
receiving an association response. Again, not often but it does happen. I am 
currently working to understand why the Cisco WLC does this and have 
extensive logging enabled on my WLC. Unfortuantely, all of the failures are 
occurring after the WLC times out my putty session!

More to come.

----- Original Message ----- 
From: "Johannes Berg" <johannes@sipsolutions.net>
To: "Chuck Crisler" <ccrisler@vgocom.com>
Cc: <linux-wireless@vger.kernel.org>
Sent: Tuesday, January 18, 2011 5:52 AM
Subject: Re: intermittent eap authentication failure


> Chuck,
>
>> Sometime ago I found a conflict between the supplicant and the MAC80211 
>> code
>> dealing with Cisco session timeouts. When we were 'deauthenticated', the 
>> MAC
>> code notified the supplicant AND re-associated with the AP.
>
> That doesn't seem right, mac80211 will never re-associate by itself.
>
>> We modified the driver so that if it received a
>> de-auth with reason code 1 (undefined?), it would *NOT* notify the
>> supplicant but would re-associate, then notify the supplicant of the new
>> association.
>
> What's that driver you're talking about? A mac80211 driver that
> reassociates by itself doesn't seem right at all.
>
> johannes
>
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