Passive Scannning

Kiran Kulkarni kiran.1267 at gmail.com
Mon Nov 10 00:03:29 EST 2008


Dan Williams wrote:
> On Fri, 2008-11-07 at 09:42 +0530, Kiran Kulkarni wrote:
>   
>> Dan Williams wrote:
>>     
>>> On Thu, 2008-11-06 at 20:41 +0530, Kiran Kulkarni wrote:
>>>   
>>>       
>>>> In wpa_supplicant I am searching for a functionality where I will put my 
>>>> system in passive scan which will only listen to beacons. And if 
>>>> networks are available I should get some notification on D-Bus or Socket 
>>>> interface.
>>>>     
>>>>         
>>> On Linux, wpa_supplicant will only request probe-scans when you have
>>> "scan_ssid=1" in a network block.  Otherwise, it's up to the driver
>>> whether passive or active scans are used.
>>>
>>> You'll get a notification on the D-Bus interface when new scan results
>>> are available, not sure about the socket interface.
>>>
>>> Dan
>>>
>>>
>>>
>>>   
>>>       
>> But I found out that in wext we can set /scan_type/ field to 
>> /IW_SCAN_TYPE_PASSIVE/ in /struct iw_scan_req/ and then make ioctl call 
>> /SIOCSIWSCAN. /But I didnt know any method exposed to do such thing.
>>
>> I agree that we get signal over D-BUS when scan results are available. 
>> My question was that can we force the driver to go into passive scanning 
>> through wpa_supplicant or we have to write seperate code to handle this 
>> case...
>>     
>
> You could modify wpa_supplicant to pass TYPE_PASSIVE if you like, but be
> aware that only a few drivers actually support that selector.
>
> Dan
>
>
>
>   
Thank you, Dan.


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