Re: Behavior with cards in rfmon mode

[Dan Williams <dcbw redhat com>]

On Thu, 2005-11-03 at 19:14 -0500, Mike Kershaw wrote:
> After dealing with some bug reports from Kismet users, we finally
> narrowed down a weird problem to an interaction with NetworkManager.
> 
> It appears that part of doing a scan for joinable networks changes the
> mode of a wireless card to managed.  This causes interesting errors in
> programs that are sniffing in monitor mode, ranging from just not
> getting packets anymore (if the driver silently ignores channel sets in
> managed mode) to failure on channel set (if it doesn't.)
> 
> It would seem to me that the simplest fix would be to ignore cards that
> are in monitor mode (and alternately put some sort of notice that
> they're being ignored in the menu/ui somewhere).
> 
> I can, of course, just tell users they have to shut down networkmanager
> beforehand, but coexisting cleanly is probably better since users often
> don't read docs.

Yeah, doing this is an odd hack because scanning really, really sucks in
Ad-Hoc mode.  So we force cards into Managed mode before we scan.  This
would break down entirely, I think, in a WPA world where the
associations with base stations are more complex since you'd possibly
have to re-auth.  So I think we should remove that bit of code and see
if there aren't better ways to make Ad-Hoc scanning work.

Dan