Association never expires after ejecting a PS-mode client card

Jouni Malinen jkmaline at
Wed Jun 25 00:49:51 EDT 2003

On Thu, Jun 19, 2003 at 11:33:34AM -0700, John Zhuge wrote:

> Set the client to PS-mode.
> And then eject the PCMCIA wireless card.
> Normally the association should expire in 5 minutes, i.e., the
> "/proc/net/hostap/wlan0/<MAC>" file disappears.
> But in this case, the association never expires.

There was a bug in Host AP driver. It was sending an empty data frame
for the station to test whether it is still around. In no error was
reported for this test, station was assumed to still be using the AP.
However, in case of power saving, the poll frame was actually buffered
and since the station did not send a PS Poll for this, no error was
actually reported.

I changed the driver to use TX status callback functionality instead of
waiting for error reports. If an acknowledgement is not received, be it
due to power save buffering or STA not being around, the station will be

When hostapd is used, another bug is causing problems for this activity
polling, and in fact, potentially for 802.11/802.1X authentication. Host
AP driver is not doing power save buffering for frames send through
wlan#ap interface, even though it should be handled similarily to wlan#
case. I need to verify whether this could be fixed easily with current
TX code. If not, it'll have to wait until I get to redesign TX path to
match with the new design one of RX path.

Jouni Malinen                                            PGP id EFC895FA

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