IBSS Association and authentication timeout

Jouni Malinen j at w1.fi
Sun Apr 1 15:02:48 EDT 2012

On Tue, Mar 27, 2012 at 02:46:57PM -0700, Anders Nilsson Plymoth wrote:
> I am running the latest snapshot version of wpa_supplicant under Android
> 4.0.2, using the nl80211 driver system. While regular client mode works
> perfectly, I can not make the device connect to IBSS networks. My setup its
> an open IBSS with no encryption. From logging I can see that the
> association process is initiated, and I get the "nl80211: Join IBSS request
> sent successfully" message. However, nothing happens and I get a
> authentication timeout.

That sounds like a driver bug.. When the IBSS network is formed (i.e.,
the driver starts beaconing), it should call cfg80211_ibss_joined().
That shows up like this in wpa_supplicant debug log:

nl80211: Event message available
nl80211: IBSS ba:9d:3d:f2:db:e4 joined
wlan0: Event ASSOC (0) received
wpa_driver_nl80211_set_operstate: operstate 0->0 (DORMANT)
netlink: Operstate: linkmode=-1, operstate=5
wlan0: Associated to a new BSS: BSSID=ba:9d:3d:f2:db:e4
wlan0: CTRL-EVENT-CONNECTED - Connection to ba:9d:3d:f2:db:e4 completed
(auth) [id=0 id_str=]

> After further inspection I can see that a physical association request
> frame is never sent, and that the mlme join ibss event is never triggered.

There are no association frames used in an IBSS (yes, that association
terminology in wpa_supplicant debug log is incorrect, but it affects
only the debug output, not actual operations).

> That is, the wifi chipset (bcm4330) never actually transmits the
> association frame. What I do see is a probe request for the SSID, and probe
> responses coming back.

Not sending the frame is fine, but not triggering that IBSS join event
is not.

> I am not sure about the specifics, but I thought association and
> authentication was needed in IBSS? Especially for an open network. If so,
> why is the code constantly trying to associate, reassociate and get
> autentication timeout?

Regardless of what the actual strings are in the debug log,
wpa_supplicant is trying to request the driver to join (or create) an
IBSS, not authenticate or associate..

> Is the problem in wpa_supplicant, the driver or both?

Based on what you described, this sounds like a driver issue
(cfg80211_ibss_joined() not called).

Jouni Malinen                                            PGP id EFC895FA

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