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Date: Wed, 1 Jun 2011 10:01:49 +0300
Message-ID: <BANLkTin4BBnUS7X-MS59mScnO5L6+mRVUQ@mail.gmail.com> (sfid-20110601_090154_291082_F47F1985)
Subject: Re: [PATCH] cfg80211: Use capability info to detect mesh beacons.
From: Eliad Peller <eliad@wizery.com>
To: Javier Cardona <javier@cozybit.com>
Cc: Vivek Natarajan <vivek.natraj@gmail.com>,
	"John W. Linville" <linville@tuxdriver.com>,
	Thomas Pedersen <thomas@cozybit.com>,
	devel@lists.open80211s.org,
	Johannes Berg <johannes@sipsolutions.net>,
	linux-wireless@vger.kernel.org, jlopex@gmail.com
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Sender: linux-wireless-owner@vger.kernel.org

On Tue, May 31, 2011 at 9:38 PM, Javier Cardona <javier@cozybit.com> wrote:
> On Tue, May 31, 2011 at 11:10 AM, Eliad Peller <eliad@wizery.com> wrote:
>> On Tue, May 31, 2011 at 8:26 PM, Javier Cardona <javier@cozybit.com> wrote:
>>> On Mon, May 30, 2011 at 3:51 AM, Vivek Natarajan <vivek.natraj@gmail.com> wrote:
>>>> On Wed, May 4, 2011 at 10:54 PM, Javier Cardona <javier@cozybit.com> wrote:
>>>>> Mesh beacons no longer use all-zeroes BSSID. ?Beacon frames for MBSS,
>>>>> infrastructure BSS, or IBSS are differentiated by the Capability
>>>>> Information field in the Beacon frame. ?A mesh STA sets the ESS and IBSS
>>>>> subfields to 0 in transmitted Beacon or Probe Response management
>>>>> frames.
>>>>
>>>> This breaks P2P mode as a P2P STA also sets the ESS and IBSS subfields
>>>> to zero. Is there any other way to find if it is a mesh other than
>>>> this check?
>>>
>>> Bummer. ?I guess that's a collision between WiFi Alliance and IEEE,
>>> respectively the organizations standardizing P2P and 802.11s.
>>> The 11s draft is pretty clear about that. ?I can consult the task
>>> group and see if they have thought about this conflict.
>>>
>>>>> index fbf6f33..62e542a 100644
>>>>> --- a/net/wireless/scan.c
>>>>> +++ b/net/wireless/scan.c
>>>>
>>>>> @@ -407,7 +407,7 @@ cfg80211_bss_update(struct cfg80211_registered_device *dev,
>>>>>
>>>>> ? ? ? ?res->ts = jiffies;
>>>>>
>>>>> - ? ? ? if (is_zero_ether_addr(res->pub.bssid)) {
>>>>> + ? ? ? if (WLAN_CAPABILITY_IS_MBSS(res->pub.capability)) {
>>>>> ? ? ? ? ? ? ? ?/* must be mesh, verify */
>>>>
>>>> Reverting the above change, makes P2P work. Any other better fix?
>>>
>>> We could check that the WLAN_CAPABILITY_IS_MBSS *and* that the bssid
>>> matches the TA. ?Do you think that would work?
>>>
>> i guess you are referring to SA (rather than TA).
>> in that case, this solution is not enough, as SA==bssid also holds
>> true for the p2p probe responses (at least when a single vif is being
>> used).
>
> Yes, you are right, SA or Address 2 ?(11s changes the address field
> definitions from DA, SA, BSSID to Address 1, 2 and 3). ?In mesh
> management frames, Address 2 always equals Address 3. ?Is this also
> the case for some P2P management frames?
>
yes.

>> btw, i've already submitted some workaround for this issue:
>> http://permalink.gmane.org/gmane.linux.kernel.wireless.general/70763
>>
>> in case we won't find a better solution...
>
> OK. ?If the answer to my question above is yes, then I guess we'll
> have to do it as you suggest. ?Thanks!
ok. thanks.