question regarding cfg80211 monitor modes

question regarding cfg80211 monitor modes

[Holger Schurig]

"iw wlan0 set type monitor" allows the following flags:

                none:     no special flags
                fcsfail:  show frames with FCS errors
                control:  show control frames
                otherbss: show frames from other BSSes
                cook:     use cooked mode

However, I don't know how to map them to the Libertas' firmware 
flags, which has

Libertas (bits can be ored)
Data frames                   0x01   
Mgmt frames but beacons       0x02
Beacons                       0x04


So I guess that the following could be a translation table:

none       0x00
fcsfail    -ENOTSUPP
control    0x02 | 0x04

But what should "otherbss" and "cook" be?

-- 
http://www.holgerschurig.de

Re: question regarding cfg80211 monitor modes

[Johannes Berg]

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On Thu, 2009-12-03 at 11:48 +0100, Holger Schurig wrote:
> "iw wlan0 set type monitor" allows the following flags:
> 
>                 none:     no special flags
>                 fcsfail:  show frames with FCS errors
>                 control:  show control frames
>                 otherbss: show frames from other BSSes
>                 cook:     use cooked mode
> 
> However, I don't know how to map them to the Libertas' firmware 
> flags, which has
> 
> Libertas (bits can be ored)
> Data frames                   0x01   
> Mgmt frames but beacons       0x02
> Beacons                       0x04
> 
> 
> So I guess that the following could be a translation table:
> 
> none       0x00
> fcsfail    -ENOTSUPP
> control    0x02 | 0x04
> 
> But what should "otherbss" and "cook" be?

"cook" and "none" only make sense while operating in a different mode at
the same time. For "cook" you get frames that the kernel hasn't
consumed. For "none" you don't influence the filters due to the monitor.
I suspect you don't support concurrent operation, so neither of those
makes sense.

fcsfail/plcpfail are probably not supported.

From what you say, "control" isn't supported either, since you were
talking about management frames, not control frames. "otherbss" is for
showing frames with a different BSSID, and in libertas monitor mode
probably always enabled.

I'd say don't bother with the flags at all.

johannes

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Re: question regarding cfg80211 monitor modes

[Holger Schurig]

> I'd say don't bother with the flags at all.

Okay, I'll then a mask of 0x07, turning everything on. If someone 
doesn't like beacons, he can still use

  tshark -R "!(wlan.fc.subtype == 8)"



BTW: 
http://wireless.kernel.org/en/users/Documentation/modes#Monitor_mode 
doesn't say anything about the modes.

-- 
http://www.holgerschurig.de

Re: question regarding cfg80211 monitor modes

[Luis R. Rodriguez]

On Thu, Dec 3, 2009 at 3:00 AM, Holger Schurig <holgerschurig@gmail.com> wrote:
>> I'd say don't bother with the flags at all.
>
> Okay, I'll then a mask of 0x07, turning everything on. If someone
> doesn't like beacons, he can still use
>
>  tshark -R "!(wlan.fc.subtype == 8)"
>
>
>
> BTW:
> http://wireless.kernel.org/en/users/Documentation/modes#Monitor_mode
> doesn't say anything about the modes.

The modes or the flags? iw does document the flags.

  Luis