Please don't puke: Modifying Frame Version, Beacon and Probe-Response values

Adrian Chadd adrian at freebsd.org
Wed Jun 1 12:18:37 PDT 2016


Hi,

Likely a mix of both. Eg, the RX filter stuff as mentioned above may
mean that you need to listen to /all/ frames for a BSS, rather than
just say data and beacon frames. If the beacon frame matching logic
checks the frame version, you need to listen to /all/ of the frames.

For power management things, it's likely none of that will work, so
you can't use things like auto-sleep based on beacon traffic / timers
/ TIM bitmap - you'd have to keep the NIC awake all the time.



-adrian


On 1 June 2016 at 04:34, Joerg Pommnitz <pommnitz at yahoo.com> wrote:
> Hi Adrian,
> does "hardware assist...will likely not work" mean "forget it, won't work"
> or "so it would have to be implemented in software instead"?
>
>
>  -- Regards       Joerg
>
>
>
>> Adrian Chadd <adrian at freebsd.org> schrieb am 17:53 Dienstag, 31.Mai 2016:
>> > Hi,
>>
>> The other thing to keep in mind is the hardware assist for things like
>> TIM parsing, wakeup, etc will likely not work. :)
>>
>>
>>
>> -a
>>
>>
>>
>> On 31 May 2016 at 03:50, Michal Kazior <michal.kazior at tieto.com> wrote:
>>>  On 31 May 2016 at 10:44, jpo <pommnitz at yahoo.com> wrote:
>>>>  Hello all,
>>>>  to implement a "Stealth feature", e.g. the WLAN network does
>> not show up in
>>>>  normal Scans, we modified the Frame version, Beacon and Probe-Response
>>>>  values for an old ATH5K card running on the now dormant Madwifi driver.
>>>>  Question: Is the same thing even POSSIBLE with ath10k? My main concern
>> is,
>>>>  that the firmware just won't handle non-standard values.
>>>>
>>>>  Can somebody who understands the division of labor between mac80211,
>> ath10k,
>>>>  the firmware and the hardware suppress his or her gag reflex long
>> enough to
>>>>  think about this?
>>>
>>>  First and foremost you'll need to use firmware with
>> "raw-mode" support
>>>  - otherwise firmware just craps over frame headers. Some 10.2.4
>>>  support it - you can look into the mailing list archive for some
>>>  discussions.
>>>
>>>  Not sure if Rx will work though as firmware-controlled Rx filters may
>>>  prevent you from receiving frames with crazy frame_control values.
>>>  You'll need to check this out yourself. Some firmware revisions might
>>>  have RX_FILTER wmi command support but this isn't used/documented
>>>  anywhere and it's questionable how much it allows you to override.
>>>
>>>  Whatever you find it'd be nice if you post whatever you find out (for
>>>  posterity :)
>>>
>>>
>>>  Michał
>>>
>>>  _______________________________________________
>>>  ath10k mailing list
>>>  ath10k at lists.infradead.org
>>>  http://lists.infradead.org/mailman/listinfo/ath10k
>>



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