MIME-Version: 1.0
In-Reply-To: <201204252054.54123.chunkeey@googlemail.com>
References: <CAFED-j=fZjXVhLKe=eOHM-rhR7g1ZvHeSMm1jUA0bdJbk4_qWQ@mail.gmail.com>
	<201204251928.21559.chunkeey@googlemail.com>
	<CAFED-j=_kPNmj-OyhFAdi_LM+rqbW6JLHC64BzdTKPyQ3iAMYg@mail.gmail.com>
	<201204252054.54123.chunkeey@googlemail.com>
Date: Thu, 26 Apr 2012 09:45:22 +0200
Message-ID: <CAFED-jkq58fjv2B+kOr5KJD4p7MUa35Pq6uP=yfCEfMa9Ujp=w@mail.gmail.com> (sfid-20120426_094609_253735_58B73B39)
Subject: Re: carl9170 - monitor mode TP drop
From: Janusz Dziedzic <janusz.dziedzic@gmail.com>
To: Christian Lamparter <chunkeey@googlemail.com>
Cc: linux-wireless <linux-wireless@vger.kernel.org>
Content-Type: text/plain; charset=ISO-8859-2
Sender: linux-wireless-owner@vger.kernel.org

W dniu 25 kwietnia 2012 20:54 u?ytkownik Christian Lamparter
<chunkeey@googlemail.com> napisa?:
> On Wednesday, April 25, 2012 08:24:23 PM Janusz Dziedzic wrote:
>> W dniu 25 kwietnia 2012 19:28 u?ytkownik Christian Lamparter
>> <chunkeey@googlemail.com> napisa?:
>> > On Wednesday, April 25, 2012 07:28:18 AM Janusz Dziedzic wrote:
>> > You see without the BIT set, the hardware won't sent any ACKs
>> > (Not even those which are directed at this interface - which of
>> > course is also bad, or even worse?) and with the BIT set (and if
>> > the HW is in Sniffer Mode) then the hardware acks every frames,
>> > even if they are for a different stations.
>> > So your fix might break someone else's setup.
>> >
>>
>> As I understand, some time ago we had wpa_supplicant AP (GO) mode
>> as a two interfaces: AP + MONITOR.
>> But now MONITOR is not used.
>> Do you know other setup?
> I think you are refering to the "cooked" monitor interface, which is
> just a monitor interface that gives you frames that mac80211 has
> not used internally [mac80211: Add cooked monitor mode support].
>
> In fact, most monitors are purly virtual interfaces, unless the
> device only has one interface and it is set into monitor mode.
> [So, if you don't want to deal with the RX_CTRL_ACK_IN_SNIFFER
> bit all you need to do is: add a monitor interface (rather than
> set the current interface into this mode) on your STA2 "client"
> <http://linuxwireless.org/en/users/Documentation/iw#Adding_interfaces_with_iw>
>
> Note: This is actually the prefered, because you can use the "normal"
> station interface to connect to the web and listen to the air with
> the virtual monitor interface on the same device at the same time!]
>
>> So, maybe firmware should ACK ?frames with correct destination address
>> only (if AR9170_MAC_RX_CTRL_ACK_IN_SNIFFER)?
>> Or that is not possible because of HW limitation?
> The ACK mechanism (as well as most of the MAC) is done by the hardware
> because of the critical timing [and lack of free space].
>

So, what steps you suggest?
I would like to record traffic from channel 6 and would like to not
have this SNIFFER ACK.

This is what I tried:
- ifconfig wlan0 up (no matter if up or down)
- iw phy phy0 interface add moni0 type monitor
- iw phy phy0 set channel 6
- ifconfig moni0 up

After last step I still see TP drop between AP and STA1 on channel6

BR
Janusz