Re: [PATCH wpan-next 01/20] net: mac802154: Allow the creation of coordinator interfaces

From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Alexander Aring <aahringo@redhat.com>
Cc: Alexander Aring <alex.aring@gmail.com>,
	Stefan Schmidt <stefan@datenfreihafen.org>,
	linux-wpan - ML <linux-wpan@vger.kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Eric Dumazet <edumazet@google.com>,
	Network Development <netdev@vger.kernel.org>,
	David Girault <david.girault@qorvo.com>,
	Romuald Despres <romuald.despres@qorvo.com>,
	Frederic Blain <frederic.blain@qorvo.com>,
	Nicolas Schodet <nico@ni.fr.eu.org>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Subject: Re: [PATCH wpan-next 01/20] net: mac802154: Allow the creation of coordinator interfaces
Date: Wed, 24 Aug 2022 15:26:48 +0200	[thread overview]
Message-ID: <20220824152648.4bfb9a89@xps-13> (raw)
In-Reply-To: <CAK-6q+gjgQ1BF-QrT01JWh+2b3oL3RU+SoxUf5t7h3Hc6R8pcg@mail.gmail.com>

Hi Alexander,

aahringo@redhat.com wrote on Wed, 24 Aug 2022 08:43:20 -0400:

> Hi,
> 
> On Wed, Aug 24, 2022 at 6:21 AM Miquel Raynal <miquel.raynal@bootlin.com> wrote:
> ...
> >
> > Actually right now the second level is not enforced, and all the
> > filtering levels are a bit fuzzy and spread everywhere in rx.c.
> >
> > I'm gonna see if I can at least clarify all of that and only make
> > coord-dependent the right section because right now a
> > ieee802154_coord_rx() path in ieee802154_rx_handle_packet() does not
> > really make sense given that the level 3 filtering rules are mostly
> > enforced in ieee802154_subif_frame().  
> 
> One thing I mentioned before is that we probably like to have a
> parameter for rx path to give mac802154 a hint on which filtering
> level it was received. We don't have that, I currently see that this
> is a parameter for hwsim receiving it on promiscuous level only and
> all others do third level filtering.
> We need that now, because the promiscuous mode was only used for
> sniffing which goes directly into the rx path for monitors. With scan
> we mix things up here and in my opinion require such a parameter and
> do filtering if necessary.

I am currently trying to implement a slightly different approach. The
core does not know hwsim is always in promiscuous mode, but it does
know that it does not check FCS. So the core checks it. This is
level 1 achieved. Then in level 2 we want to know if the core asked
the transceiver to enter promiscuous mode, which, if it did, should
not imply more filtering. If the device is working in promiscuous
mode but this was not asked explicitly by the core, we don't really
care, software filtering will apply anyway.

I am reworking the rx path to clarify what is being done and when,
because I found this part very obscure right now. In the end I don't
think we need additional rx info from the drivers. Hopefully my
proposal will clarify why this is (IMHO) not needed.

Thanks,
Miquèl