Message-ID: <54F974B2.5050604@gmail.com> (sfid-20150306_103452_532164_77B52CE0)
Date: Fri, 06 Mar 2015 10:34:42 +0100
From: wim torfs <wtorfs@gmail.com>
MIME-Version: 1.0
To: Marco <marco@tampabay.rr.com>
CC: Christian Lamparter <chunkeey@googlemail.com>,
	linux-wireless@vger.kernel.org
Subject: Re: carl1970: monitor mode only displaying beacons/probs from APs?
References: <20150304230225.J5EHX.13935.root@cdptpa-web27> <3859987.D1VAPy8h72@debian64> <54F93907.6020408@tampabay.rr.com>
In-Reply-To: <54F93907.6020408@tampabay.rr.com>
Content-Type: text/plain; charset=windows-1252; format=flowed
Sender: linux-wireless-owner@vger.kernel.org

Hi,

On 03/06/2015 06:20 AM, Marco wrote:
> On 03/05/15 06:10, Christian Lamparter wrote:
>> Hello,
>>
>> On Wednesday, March 04, 2015 11:02:25 PM marco@tampabay.rr.com wrote:
>>> Quite a while back after doing an upgrade to the latest (back then)
>>> compat-wireless, I noticed that I was only seeing beacon,prob requests, and
>>> the occasional data packet when in monitor mode; which at the time I wrote
>>> off.  After switching to backports-3.18.1-1 recently, I still see the same
>>> behavior(on x86 and arm).  I'm sure I'm missing something, but I couldn't
>>> find any references to this behavior in my search.  I also tried "iw wlanX
>>> set monitor control otherbss" to no avail.  Switching to a different chipset
>>> using ath9k-htc showed expected traffic.
>>>
>>> Can anyone point me in the right direction?
>> maybe. Could it be that you are looking for 802.11n(MCS) data frames?
>
> I'm trying to see any and all frames (ctrl/mgmt/data).  I'm currently
> doing my testing on 2.4ghz band, channel 11.  Playing with HT didn't
> seem to make a difference.
>
>
>> Because by default, carl9170's monitor mode only catches the legacy
>> 802.11a/b/g frames. If this is the case, then try setting the right
>> channel mode (HT20/HT40+/HT40-) when selecting the channel. i.e.:
>>
>> # iw dev wlanX set channel Y HT20
>> # iw dev wlanX set channel Y HT40+
>>
>> I hope this helps. Otherwise, you could try:
>>
>> # iw dev wlanX set monitor [...] fcsfail
>>
>> and see if you are picking up frames this way. This should work, but you
>> will be picking up mostly damaged stuff, so some extra frame processing
>> will be needed to filter out the noise.
>>
>> Regards,
>>    Christian
>>
>
> I've previously (and once again for good measure) tried fcsfail to no
> avail as well.
>
> I'm surprised no one else is seeing this/reported this, I've tried on
> 3 separate linux boxes now with no luck.
>

Perhaps a silly question, and I'm sure you already covered this, but I 
need to ask, just to be sure. Did you enable promiscuous mode to capture 
the data packets?

Could you elaborate on the employed method for capturing the data, it is 
difficult to make any suggestions without having knowledge about the 
used procedure.

Best Regards,
Wim.


> Regards,
> Marco
> --
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