problem with management frames (0.0.4 and later)

[Jouni Malinen]

On Mon, Oct 06, 2003 at 12:14:20PM +0100, Petr Novak wrote:

> sorry for the delay, this is a dump of the problem announced last week with 
> recent CVS versions of hostAP while handling association/authentication. It 
> works 100% in 0.0.3 and works really bad in 0.0.4 and later. All firmware is 
> STA1.7.4, all stations are hostAP same version. The sniffed WLAN is wlan2, 
> MAC addr replaced by AP:AP:AP:AP:AP, station MAC mapped to STA0x:STA0x:STA0x.

Did you happen to iwconfig txpower in the AP or STAs? It was removed in
0.0.4. If you did not configure TX power explicitly with iwconfig, this
should not have changed anything, though.

If I remember correctly, all your STAs were quite long way away from the
AP. Have you tested the AP with another STA that would be close to the
AP?

> Let's start with a good sniff and syslog, 0.0.3:

OK, that sniff log was good for reference numbers. STA04 managed to
authenticate and associate without any problems. STA03 had some issues;
maybe due to dropped frames. Sniffer was clearly unable to receive all
frames.

> and now the bad one:
> 
> Oct  4 12:44:39 dobgw kernel: wlan2: STA04:STA04:STA04 auth_cb - frame was 
> not ACKed

Unfortunately, this sniffer log did not include the most interesting
information for me, i.e., the time used between the authentication frame
from STA and the reply from AP. It would be useful to see these frames
(i.e., auth transaction #1 and #2 and all ACKs related to them) in one
sniffer log. Some STA implementations seem to not ACK authentication
frame from the AP if it takes too long time to receive that after STA's
own authentication frame was sent.

The frame exchanges in this sniffer log looked somewhat odd.. The AP
seemed to be able to receive all management frames from the STA (since
it ACKed them), but it did not seem to receive ACK/CTS frames from the
STA (since it retried sending the original data/RTS frame). This is
quite low-level issue and the driver does not really have much control
about retries/ACKs.

I don't remember changes anything that should cause something like this
between 0.0.3 and 0.0.4, but then again, quite a bit of code changed
between those versions. You could at least verify that the BBP and MAC
configuration is same by comparing "utils/hostap_diag -a wlan#" output
from the same card running 0.0.3 and 0.0.4 version of the driver.

-- 
Jouni Malinen                                            PGP id EFC895FA