wpa-supplicant v0.7.2 stops roaming after a while

[Dan Williams]

On Wed, 2010-04-28 at 17:36 +0200, Michel Marti wrote:
> I'll try again ;-)
> 
> on 04/28/2010 04:41 PM Michel Marti said the following:
> > I noticed that after running for a while, wpa-supplicant (v0.7.2) stops roaming to a
> > better AP altough the scan results clearly contain a (much) stronger AP.
> > 
> > Driver in use is madwifi (latest from 0.9.4 branch). I have set the background scan
> > interval on the card to 30 seconds (iwpriv ath0 bgscanintvl 30).
> > 
> 
> I had another look at my wpa-supplicant debug log file. The stronger AP somehow gets
> permanently blacklisted, causing the wpa-supplicant to subsequently ignore it...
> 
> # grep '00:18.*blacklist' supplicant.log
> 1272466406.053706: Added BSSID 00:18:39:d4:63:a4 into blacklist
> 1272466420.241335: Removed BSSID 00:18:39:d4:63:a4 from blacklist
> 1272466497.852958: Added BSSID 00:18:39:d4:63:a4 into blacklist
> 1272466507.139660: Removed BSSID 00:18:39:d4:63:a4 from blacklist
> 1272466618.728815: Added BSSID 00:18:39:d4:63:a4 into blacklist
> 1272466627.775176: Removed BSSID 00:18:39:d4:63:a4 from blacklist
> 1272466629.992936: Added BSSID 00:18:39:d4:63:a4 into blacklist
> 1272466642.499455: BSSID 00:18:39:d4:63:a4 blacklist count incremented to 2
> 1272466644.329980: Removed BSSID 00:18:39:d4:63:a4 from blacklist
> 1272466646.274820: Added BSSID 00:18:39:d4:63:a4 into blacklist
> 1272466844.741239: BSSID 00:18:39:d4:63:a4 blacklist count incremented to 2
> 
> Later on:
> 1272466857.040626: 0: 00:18:39:d4:63:a4 ssid='4YEO' wpa_ie_len=28 rsn_ie_len=24 caps=0x11
> 1272466857.040711:    skip - blacklisted
> ...
> 
> # wpa_cli status
> Selected interface 'ath0'
> bssid=00:15:70:56:ff:90
> ssid=4YEO
> id=0
> mode=station
> pairwise_cipher=CCMP
> group_cipher=CCMP
> key_mgmt=WPA2-PSK
> wpa_state=COMPLETED
> ip_address=192.168.0.233
> 
> 
> # wpa_cli scan_results
> Selected interface 'ath0'
> bssid / frequency / signal level / flags / ssid
> 00:18:39:d4:63:a4	2462	229	[WPA-PSK-TKIP+CCMP][WPA2-PSK-TKIP+CCMP][ESS]	4YEO
> 00:15:70:56:ff:90	2437	203	[WPA2-PSK-CCMP][ESS]	4YEO
> [...snip...]
> 
> What could be the reason for the blacklisting of the AP?

A number of reasons:

1) the driver sent a WEXT disassoc event, indicating that it lost sync
with the AP, or the driver is buggy, or whatever.  This looks like:

CTRL-EVENT-DISCONNECTED - Disconnect event - remove keys

2) association to the AP was rejected by the AP.  I don't know what this
one looks like in the logs.

3) authentication to the AP timed out.  This looks like:

Authentication with 00:22:33:44:d9:28 timed out.


I'd guess your issue is case #1.  Can you provide more of the logs?
You'll probably see something in the supplicant logs for it.  You can
also try to turn on madwifi module debugging and figure out why the
driver is sending disconnect events up to the supplicant.

Dan