Message-ID: <45E709EF.6060200@warmcat.com>
Date: Thu, 01 Mar 2007 17:14:23 +0000
From: Andy Green <andy@warmcat.com>
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To: Ivo van Doorn <ivdoorn@gmail.com>
CC: linux-wireless@vger.kernel.org
Subject: Re: Question about packet injection
References: <45E41A9E.2020908@warmcat.com> <45E497A1.90400@warmcat.com> <45E6ED0B.20100@warmcat.com> <200703011622.17602.IvDoorn@gmail.com>
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Ivo van Doorn wrote:
> On Thursday 01 March 2007 16:11, Andy Green wrote:
>> Hi folks -
>>
>> As suggested here I migrated my daemon to using a per-physical device 
>> monitor mode interface it creates and destroys from usermode, together 
>> with libpcap for filtering and receiving broadcasts and that seems to be 
>> working okay.  So that is half the battle to get the broadcast system 
>> working with mac80211 out of the box without patches.
>>
>> However, if I inject a captured packet - with a PRISM header prepended - 
>> down the Monitor mode interface using pcap_inject(), I see it appear on 
>> the libpcap captured output okay, but it does not go out on the air AFAICT.
>>
>> Is this in fact the correct way to try to inject a packet with fine 
>> control over its encryption and rate?  If so is it expected to currently 
>> work on iwlwifi 0.0.8 or rt2x00 (rt73usb) from CVS 2008-02-14?
> 
> Note that rt73usb is currently broken, I know that RX isn't working
> because scanning fails. Chances are quite high that TX is failing too.
> I am still looking into that issue, but it might be the reason why
> packet injection is failing for you.

The 2007-02-14 rt73usb CVS works okay for RX, it does iwlist wlan0 scans 
alright here anyway with the AP shown.  I have had that version issuing 
unencrypted broadcasts too by hacking the stack and the driver slightly. 
  Maybe it was some Valentines Day magic :-)  But it doesn't associate 
in a stable way with the AP using WPA on wpa_supplicant with the dscape 
patch.

Anyway it seems the problem is one does not inject for TX on the Monitor 
mode interface (/me goes away to grep and google what a Management mode 
interface does, thanks Johannes)

-Andy