Monitor mode with RTL8187

Monitor mode with RTL8187

[Jorge Lucángeli Obes]

Hi all,
I've come into possession of a RTL8187-based wireless USB adapter
(Encore ENUWI-G2). I am trying the new RTL8187 driver in wireless-dev
GIT. The question is: does this driver support monitor mode?

tamsyn@rory:~$ sudo iwconfig wlan0 mode monitor
Error for wireless request "Set Mode" (8B06) :
    SET failed on device wlan0 ; Device or resource busy.

Any clues? Please CC me as I'm not subscribed to the list. Thanks in advance.

Jorge

Re: Monitor mode with RTL8187

[Andy Green]

Jorge Luc=E1ngeli Obes wrote:
> Hi all,
> I've come into possession of a RTL8187-based wireless USB adapter
> (Encore ENUWI-G2). I am trying the new RTL8187 driver in wireless-dev
> GIT. The question is: does this driver support monitor mode?
>=20
> tamsyn@rory:~$ sudo iwconfig wlan0 mode monitor
> Error for wireless request "Set Mode" (8B06) :
>    SET failed on device wlan0 ; Device or resource busy.
>=20
> Any clues? Please CC me as I'm not subscribed to the list. Thanks in
> advance.

mac80211 needs you to bring the interface down before changing the mode

ifconfig wlan0 down

Then after changing the mode, bring it up and set the channel.

-Andy
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Re: Monitor mode with RTL8187

[Stefan Schweizer]

Andy Green wrote:
> ifconfig wlan0 down
> 
> Then after changing the mode, bring it up and set the channel.

why can it not do that automatically when issueing the mode monitor command?

Seems usability has not yet reached wireless configuration - where it is imo
much needed.

-Stefan

Re: Monitor mode with RTL8187

[Michael Buesch]

On Tuesday 10 July 2007 10:07:02 Stefan Schweizer wrote:
> Andy Green wrote:
> > ifconfig wlan0 down
> > 
> > Then after changing the mode, bring it up and set the channel.
> 
> why can it not do that automatically when issueing the mode monitor command?
> 
> Seems usability has not yet reached wireless configuration - where it is imo
> much needed.

ehm, setting the mode means setting the mode. Not bringing the device
up, changing channels or something like that.
The time where some wireless config commands magically trigger unrelated
events (ESSID setting triggers assoc) is over, with the advent of cfg80211.
And that is _good_.

-- 
Greetings Michael.

Re: Monitor mode with RTL8187

[Johannes Berg]

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On Tue, 2007-07-10 at 10:50 +0200, Michael Buesch wrote:

> > Seems usability has not yet reached wireless configuration - where it is imo
> > much needed.
> 
> ehm, setting the mode means setting the mode. Not bringing the device
> up, changing channels or something like that.
> The time where some wireless config commands magically trigger unrelated
> events (ESSID setting triggers assoc) is over, with the advent of cfg80211.
> And that is _good_.

Seconded. usability ≠ magic, I'd go as far as saying that magic excludes
usability. also, usability ∉ kernel :)

johannes

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Re: Monitor mode with RTL8187

[Andy Green]

Stefan Schweizer wrote:
> Andy Green wrote:
>> ifconfig wlan0 down
>>
>> Then after changing the mode, bring it up and set the channel.
> 
> why can it not do that automatically when issueing the mode monitor command?
> 
> Seems usability has not yet reached wireless configuration - where it is imo
> much needed.

It's really a userspace issue... libpcap could be given the primitives
so tcpdump or whatever can set the mode and bring the interface up.

On the same subject, why is scanning done by a separate app (iwlist)
from iwconfig?  Why is scanning specially modal in the stack (or even
worse the device firmware) when there are enough primitives lying around
to do it from userspace?  I guess the answer is it got started like that
and now people are using it that way changing is harder.

BTW apropos of nothing let me note that the try #13 injection patches
apply to current wireless-dev with only a single fuzz, and are available
right here:

[PATCH Try#lucky13 1/3] mac80211: Monitor mode radiotap injection docs
http://www.spinics.net/lists/linux-wireless/msg03055.html

[PATCH Try#lucky13 2/3] cfg80211: Radiotap parser
http://www.spinics.net/lists/linux-wireless/msg03056.html

[PATCH Try#lucky13 3/3] mac80211: Monitor mode radiotap-based packet
injection
http://www.spinics.net/lists/linux-wireless/msg03054.html

-Andy