Message-ID: <1340728873.4484.6.camel@jlt3.sipsolutions.net> (sfid-20120626_184123_811268_1FD86518)
Subject: Re: Help tracing NL80211_CMD_AUTHENTICATE as event in IBSS mode
From: Johannes Berg <johannes@sipsolutions.net>
To: Will Hawkins <hawkinsw@opentechinstitute.org>
Cc: Will Hawkins <hawkinsw@opentechinitiative.org>,
	linux-wireless@vger.kernel.org
Date: Tue, 26 Jun 2012 18:41:13 +0200
In-Reply-To: <4FE9E201.1010903@opentechinstitute.org>
References: <24f-4fe93400-17-239c5900@2266046>
	  (sfid-20120626_061218_757773_249E152D) <1340693584.4662.3.camel@jlt3.sipsolutions.net>
	 <4FE9E201.1010903@opentechinstitute.org>
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Sender: linux-wireless-owner@vger.kernel.org

On Tue, 2012-06-26 at 12:23 -0400, Will Hawkins wrote:

> >> "When used as an event, this reports reception of an Authentication
> >> frame in station and IBSS modes when the local MLME processed the
> >> frame, i.e., it was for the local STA and was received in correct
> >> state."
> >>
> >> I very much want this to be true for IBSS modes. However, I cannot
> >> seem to trace through the source code to confirm that this actually
> >> happens. I can easily follow the code for the case when the interface
> >> is in station mode but lose the trail for IBSS. 
> > 
> > I'm afraid that isn't actually true for IBSS. The event you get there
> > will be NL80211_CMD_NEW_STATION.
> 
> Thank you for the sanity check! Do you think it's worthwhile to patch
> the nl80211.h file to address this?

Yes, we should remove the IBSS text here :-)

> > I think in your case though, what you really want is a NL80211_CMD_FRAME
> > event? You register for auth frames, also to prevent mac80211 from
> > handling them itself, and then they get diverted to cfg80211_rx_mgmt()
> > and on to nl80211_send_mgmt().
> 
> Thanks for this, as well. As far as the patch that I submitted, you are
> exactly correct. I was only investigating this other method since it
> appears that's how wpa_supplicant claims to support IBSS RSN.
> wpa_supplicant never actually registers for AUTH frames (through
> NL80211_CMD_REGISTER) and relies solely on the NL80211_CMD_AUTHENTICATE
> to actually receive copies of those frames.

Huh, now I'm confused, why would it need the authenticate frames for
IBSS? As far as I can tell, it looks at CMD_NEW_STA, which calls
nl80211_new_station_event(), which in IBSS sends EVENT_IBSS_RSN_START to
the supplicant core -- that will trigger the 4-way-handshake. No? Hence
it doesn't need to register for auth frames, it never needs them, since
RSN uses open auth, if any is even used in IBSS at all.

johannes