Re: Passive Scanning not supported?

On Wednesday 26 July 2006 07:43, Zhu Yi wrote:
> On Tue, 2006-07-25 at 12:53 +0200, Thomas King wrote:
> > Hi all,
> > I try to do passive scanning with ipw2200-1.1.3, however, it looks like
> > it doesn't work. I wrote a small program using the Wireless Tools version
> > 29-pre10 (beta). I set the scan_type in the iw_scan_req
> > struct to IW_SCAN_TYPE_PASSIVE and link this struct to the iwreq struct.
> > The iwreq struct is then used by the iw_set_ext function. However, if I
> > invoke the passive scanning program I see a Probe Request packet on the
> > channel from the machine that is supposed to do a passive scan.
>
> Did you set IW_SCAN_THIS_ESSID? If so, ipw2200 will think you want an
> active scan for this ssid even if IW_SCAN_TYPE_PASSIVE is provided.
>
> > I think the reason for this is that in the ipw_wx_set_scan function there
> > is no distiction between active and passive scanning because
> > ipw_request_direct_scan is invoked. Ipw_wx_set_scan is more or less
> > directly called by the iw_set_ext function.
>
> ipw_request_scan() performs the scan request to the firmware. Currently
> if STA is not in monitor mode or roaming, it will do an active broadcast
> scan. While from your description, if IW_SCAN_TYPE_PASSIVE is given, we
> should actually do a passive scan (IPW_SCAN_PASSIVE_FULL_DWELL_SCAN).
>
> Would you like to provide a patch to fix that? And try to see if the
> probe request frames are not actually sent out by the card.
I hacked the passive scanning support. Unfortunately, I am not an experienced 
kernel or wireless network card driver hacker, so I suggest someone with more 
experience than I have should review my code. I am going to prepare a patch. 
Should I post my patch here on this mailinglist?

Greetings,
Thomas

-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys -- and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV