wpa_supplicant ad-hoc settings

Per-Henrik Lundblom per-henrik.lundblom at connectblue.com
Thu Nov 18 08:13:29 EST 2010


Hi,

I'm working with WLAN driver development and have more than once tried 
to understand the idea behind the ad-hoc support implemented in the 
wpa_supplicant.

My main concern is that wpa_supplicant discards scan results matching 
the configured ad-hoc network because it is an IBSS network. Example config:

ctrl_interface=/var/run/wpa_supplicant
network={
         mode=1
         ssid="ph-adhoc"
         key_mgmt=NONE
}

This will get the wpa_supplicant to scan for a matching network but the 
right on is discarded with the following message (running with -d):

14: 3e:f3:e6:f4:27:9b ssid='ph-adhoc' wpa_ie_len=0 rsn_wlan0:     key[2]:
ie_len=0 caps=0x2
    skip - IBSS (adhoc) network

In the later versions of wpa_supplicant it will go on and try to create 
it's own network when no matches are found. In older versions it just 
looped forever trying to find a matching network (which it actually does 
but rejects it).

So, in my eyes the ad-hoc support in wpa_supplicant is, and has always 
been, broken. Am I missing something?

For me the expected behavior would be:

wpa_supplicant does a complete scan and matches the result with the 
network configuration. If match is found, wpa_supplicant then configures 
SSID, BSSID, channel and operation mode so that the WLAN driver joins 
the ad-hoc network. If no match is found, it configures SSID, channel 
(from the frequency configuration directive) and operation mode so that 
the WLAN driver can create it's own ad-hoc network.

Any input would be great!

Regards,

PH

-- 
Per-Henrik Lundblom
System engineer

connectBlue AB
Norra Vallgatan 64 3V, SE-211 22 Malmö, Sweden
Tel. +46 40 6307100, Direct tel. +46 40 6307126
Cellular +46 733 207126, Fax +46 40 237137
per-henrik.lundblom at connectblue.com
www.connectblue.com



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