Selective scanning

Ajeet Nankani fromkth+hostap at fastmail.fm
Mon Mar 21 06:52:31 EST 2005


I am currently involved more or less into same kind of thing that is
selective scanning, but only in STA mode.

My task is to do selective active scanning, can you help me a little bit 
where and what to change in scanning functions and or structures to 
accomplish this scanning of particular channel.

Do i have to write separate program for that?

After reading the code, it seems that in file "hostap_ioctl.c" function

static int prism2_request_hostscan(struct net_device *dev,
				   u8 *ssid, u8 ssid_len

is called when the host requests a scan(RID FCE5).
In that function, channels to be scanned are copied from local->channel_mask
 From inspecting RID-FCE5, it seems that this channel_mask gets channel 
list from RID-FD10, but exactly where in the code this channel_mask gets 
populated with the channel list. Can you point out this?

Also as this host scan (RID-FCE5) gives option to specify the subset of 
channels to be scanned, so to implement that, only particular different 
channels be scanned every time when it is called, should not be that 
much hard.

Thanks,

-ajeet.



Marcin Dabrowski wrote:
> Hi,
> 
> 	I'm trying to implement selective scanning in HostAp.
> I would like to change the local->passive_scan_timer.function
> from hostap_passive_scan to my function - for example my_scanning.
> my_scannig function could work as below:
> 1) it would check the singnal stregth by calling
> local->func->get_rid(local->dev,HFA384X_RID_COMMSQUALITY...) function
> 2) then it could scan my channel by calling local->func->set_rid(dev,
> HFA384X_RID_SCANREQUEST...) function
> 3) then it would check local->channel_mask whether the chosen channel
> can be used
> 
> Is that scenario correct ???
> 
> Thanks,
> Marcin




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