P2P Channel list: Applying regulatory rules

Krishna Chaitanya chaitanya.mgit
Wed Dec 17 09:47:47 PST 2014

On Wed, Dec 17, 2014 at 11:11 PM, Jouni Malinen <j at w1.fi> wrote:
> On Wed, Dec 17, 2014 at 09:05:47PM +0530, Krishna Chaitanya wrote:
>> P2P spec 1.5 tells that:
>> > The Channel List attribute shall indicate the channels that the P2P Device can support as Operating Channel of the P2P Group if it becomes P2P Group Owner.
> Please keep in mind that this is in a section that specifically
> discusses GO Negotiation Request and as such, that sentence doesn't have
> much to do with what other frame with the Channel List attribute may do.
>> So in p2p_buf_add_channel_list We should take in to account the
>> reg_class flags and accordingly should avoid NO_IR/RADAR/PASSIVE-SCAN
>> channels from the channel list? because we cannot start AP operation
>> in those channels.
> Not in that function since it is used for other purposes than just GO
> Negotiation Request.
>> How do we handle Auto-GO/non-Auto-GO, for regulatory rules. Spec is
>> not clear about this.
> There are large number of unclear parts related to how the operating
> channel can get negotiated in number of corner cases (and even not so
> corner cases).
>> I am preparing a patch to remove those channels for now, later we can
>> extend to check for DFS availability also.
>> But want to confirm before spending too much time.

Thanks Jouni, i understand and agree with you, spec is very unclear
regarding regulatory.
> If I understood what you are proposing, I would be quite unlikely to
> accept such a change. This area in P2P has required significant
> fine-tuning to cover practical use cases and I'm not going to be undoing
> those based on that one sentence in the spec.
Wouldn't we violating the spec, even if its one line?
> None of the DFS channels are included in the P2P channel list now
> anyway and there is already quite a bit of conditions removing channels
> on which the device cannot become a GO.

While preparing the channel list i dont see any conditions?
We are using WORLD mode, where entire band is disabled
for use in 5GHz for AP operation and it list all domains in 5GHZ.

> If you have a specific example
> of a case where some channels should be removed, I'd suggest providing a
> wpa_supplicant debug log and sniffer capture of an exchange as a
> justification for a proposed change. Without those, I don't think I'd
> accept changes in this area.
Sure, i dont have anything readymade, but will provide you one soon.

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