Re: [PATCH 02/10] wl12xx: AP-mode - fix race condition on sta connection

[Johannes Berg <johannes@sipsolutions.net>]

On Thu, 2011-01-27 at 02:20 +0200, Jouni Malinen wrote:
> On Wed, Jan 26, 2011 at 11:08:39PM +0100, Johannes Berg wrote:
> > If we add the station before the response frame's ACK is received, we
> > still have the race, and we need to delete if we don't get the ACK. If
> > we add the station before we send the assoc response we get rid of this
> > race, but also have to delete if we don't get the ACK. I guess that case
> > is actually nicer in some way since we would have allowed the station to
> > connect, so if spurious data frames go up because we don't get an ACK
> > from the station that's no big deal?
> 
> From the correctness view point, the STA entry would need to be enabled
> (added/marked associated) at the moment the ACK frame is received. Since
> we do some internal processing between kernel and user space, there is
> obviously some latency involved. The most correct mechanism would be to
> make hostapd add a not-associated-STA entry before sending association
> response with status code 0 and request mac80211 to mark it associated
> automatically on TX status report (showing success) from the driver.
> However, for practical purposes, that may be too complex and doing what
> you describe above is likely good enough.

It's possible to do that as well -- but do we want to change any of
this? It might be good, but it's mostly a hostapd change I think?

johannes