[isf-wifidog] Still trying to hunt down greg's problem and #269

[Benoit Grégoire]

I've been trying unsuccessfully to hunt a bug down on IRC with greg, and it's 
very likely that the cause is the same as http://dev.wifidog.org/ticket/269.  

The date comparison calculations for tokens appear to be failing.  In this 
case, the offset makes wifidog to think that the token is still valid before 
it expired, and manifests as users not logging off automatically after a 
gateway crash or session expiration.  In greg's case (offset probably the 
other way around), it manifests as users successfully logging in during 
initial auth (as shown by the gateway debug output) but getting logged off 
during the next counter update.  I checked that the calculation hasn't been 
broken in recent postgres, and that we are using the proper datatype.  So 
most likely, in both cases, you have an improperly set timezone in either PHP 
or Postgres.  

It should be possible to fix this easily in the wifidog code now that we no 
longer intend to support MySql, but I need to first confirm that a timezone 
mismatch between PHP and Postgres is indeed the cause.

So anyone who encounteres/encountered this bug, please check this and report 
your results.
-- 
Benoit Grégoire
http://benoitg.coeus.ca/