IBSS mode and scanning

IBSS mode and scanning

[Holger Schurig]

Hi list !

I now try for the first time ever to do some IBSS/ADHOC
networking (so that I can implement this for libertas+cfg80211).

I noticed several things:



Documentation
-------------
http://linuxwireless.org/en/users/Documentation/iw doesn't have
any example. Via google, I found
http://linuxwireless.org/en/users/Documentation/iw/replace-iwconfig,
but this example is wrong, e.g. the frequency isn't specified.

As I'm not yet an authoritative instance for IBSS questions, I
won't fix those wiki pages --- yet.



Scanning while in IBSS mode?
----------------------------
I finally settled to use these commands:

dmesg -c >/dev/null
iw dev wlan0 set type ibss
ifconfig wlan0 192.168.1.2 up
iw --debug dev wlan0 ibss join ADHOC 2412

This seemed to work, but then I tried to look at the beacon. This
was just not possible using "iw":

iw dev wlan0 scan freq
iw dev wlan0 scan freq 2412

didn't work. But, oh wonder, it worked via "iwlist eth1 scan".
For me it looks like a but that I have to use a WEXT tool to
check for ADHOC beacons while in IBSS mode.




DMESG spamming
--------------
At first, my dmesg looked quite reasonable:

[22313.286690] phy0: device now idle
[22313.292241] phy0: device no longer idle - in use
[22313.292647] wlan0: Trigger new scan to find an IBSS to join
[22316.000249] wlan0: Trigger new scan to find an IBSS to join
[22320.000336] wlan0: Trigger new scan to find an IBSS to join
[22322.000444] wlan0: Creating new IBSS network, BSSID 4e:9d:b6:88:b7:9b

but then something started to spam it (Note that I did *NOT* yet operate another IBSS mode):

[22352.000210] wlan0: No active IBSS STAs - trying to scan for other IBSS networks with same SSID (merge)
[22352.032050] wlan0: No active IBSS STAs - trying to scan for other IBSS networks with same SSID (merge)
[22352.068034] wlan0: No active IBSS STAs - trying to scan for other IBSS networks with same SSID (merge)
[22352.108035] wlan0: No active IBSS STAs - trying to scan for other IBSS networks with same SSID (merge)
[22352.140057] wlan0: No active IBSS STAs - trying to scan for other IBSS networks with same SSID (merge)
[22352.176038] wlan0: No active IBSS STAs - trying to scan for other IBSS networks with same SSID (merg
...
ad-infinitum

-- 
http://www.holgerschurig.de