From: Alexander Aring <aahringo@redhat.com>
To: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Stefan Schmidt <stefan@datenfreihafen.org>,
Alexander Aring <alex.aring@gmail.com>,
linux-wpan - ML <linux-wpan@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>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Network Development <netdev@vger.kernel.org>
Subject: Re: [PATCH wpan-next 1/6] net: ieee802154: Drop coordinator interface type
Date: Mon, 20 Jun 2022 21:54:33 -0400 [thread overview]
Message-ID: <CAK-6q+jR00MD+W02AAH8P5xG7hUD-x8NEnOG_W3mifj=6ybBzg@mail.gmail.com> (raw)
In-Reply-To: <20220620111922.51189382@xps-13>
Hi,
On Mon, Jun 20, 2022 at 5:19 AM Miquel Raynal <miquel.raynal@bootlin.com> wrote:
...
> >
> > > - Beacons can only be sent when part of a PAN (PAN ID != 0xffff).
> >
> > I guess that 0xffff means no pan is set and if no pan is set there is no pan?
>
> Yes, Table 8-94—MAC PIB attributes states:
>
> "The identifier of the PAN on which the device is operating. If
> this value is 0xffff, the device is not associated."
>
I am not sure if I understand this correctly but for me sending
beacons means something like "here is a pan which I broadcast around"
and then there is "'device' is not associated". Is when "associated"
(doesn't matter if set manual or due scan/assoc) does this behaviour
implies "I am broadcasting my pan around, because my panid is !=
0xffff" ?
> > > - The choice of the beacon interval is up to the user, at any moment.
> > > OTHER PARAMETERS
> >
> > I would say "okay", there might be an implementation detail about when
> > it's effective.
> > But is this not only required if doing such "passive" mode?
>
> The spec states that a coordinator can be in one of these 3 states:
> - Not associated/not in a PAN yet: it cannot send beacons nor answer
> beacon requests
so this will confirm, it should send beacons if panid != 0xffff (as my
question above)?
> - Associated/in a PAN and in this case:
> - It can be configured to answer beacon requests (for other
> devices performing active scans)
> - It can be configured to send beacons "passively" (for other
> devices performing passive scans)
>
> In practice we will let to the user the choice of sending beacons
> passively or answering to beacon requests or doing nothing by adding a
> fourth possibility:
> - The device is not configured, it does not send beacons, even when
> receiving a beacon request, no matter its association status.
>
Where is this "user choice"? I mean you handle those answers for
beacon requests in the kernel?
> > > - The choice of the channel (page, etc) is free until the device is
> > > associated to another, then it becomes fixed.
> > >
> >
> > I would say no here, because if the user changes it it's their
> > problem... it's required to be root for doing it and that should be
> > enough to do idiot things?
>
> That was a proposal to match the spec, but I do agree we can let the
> user handle this, so I won't add any checks regarding channel changes.
>
okay.
> > > ASSOCIATION (to be done)
> > > - Device association/disassociation procedure is requested by the
> > > user.
> >
> > This is similar like wireless is doing with assoc/deassoc to ap.
>
> Kind of, yes.
>
In the sense of "by the user" you don't mean putting this logic into
user space you want to do it in kernel and implement it as a
netlink-op, the same as wireless is doing? I just want to confirm
that. Of course everything else is different, but from this
perspective it should be realized.
> > > - Accepting new associations is up to the user (coordinator only).
> >
> > Again implementation details how this should be realized.
>
> Any coordinator can decide whether new associations are possible or
> not. There is no real use case besides this option besides the memory
> consumption on limited devices. So either we say "we don't care about
> that possible limitation on Linux systems" or "let's add a user
> parameter which tells eg. the number of devices allowed to associate".
>
> What's your favorite?
>
Sure there should be a limitation about how many pans should be
allowed, that is somehow the bare minimum which should be there.
I was not quite sure how the user can decide of denied assoc or not,
but this seems out of scope for right now...
> > > - If the device has no parent (was not associated to any device) it is
> > > PAN coordinator and has additional rights regarding associations.
> > >
> >
> > No idea what a "device' here is, did we not made a difference between
> > "coordinator" vs "PAN coordinator" before and PAN is that thing which
> > does some automatically scan/assoc operation and the other one not? I
> > really have no idea what "device" here means.
>
> When implementing association, we need to keep track of the
> parent/child relationship because we may expect coordinators to
> propagate messages from leaf node up to their parent. A device without
> parent is then the PAN coordinator. Any coordinator may advertise the
> PAN and subsequent devices may attach to it, this is creating a tree of
> nodes.
>
Who is keeping track of this relationship? So we store pans which we
found with a whole "subtree" attached to it?
btw: that sounds similar to me to what RPL is doing...,
- Alex
next prev parent reply other threads:[~2022-06-21 1:54 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-03 18:21 [PATCH wpan-next 0/6] net: ieee802154: PAN management Miquel Raynal
2022-06-03 18:21 ` [PATCH wpan-next 1/6] net: ieee802154: Drop coordinator interface type Miquel Raynal
2022-06-04 2:01 ` Alexander Aring
2022-06-06 15:43 ` Miquel Raynal
2022-06-07 3:04 ` Alexander Aring
2022-06-07 16:16 ` Miquel Raynal
2022-06-08 13:47 ` Miquel Raynal
2022-06-08 14:37 ` Miquel Raynal
2022-06-09 2:06 ` Alexander Aring
2022-06-09 2:23 ` Alexander Aring
2022-06-09 15:43 ` Miquel Raynal
2022-06-11 12:05 ` Alexander Aring
2022-06-15 9:15 ` Miquel Raynal
2022-06-09 1:56 ` Alexander Aring
2022-06-09 15:52 ` Miquel Raynal
[not found] ` <CAK-6q+jchHcge2_hMznO6fwx=xoUEpmoZTFYLAUwqM2Ue4Lx-A@mail.gmail.com>
2022-06-17 15:12 ` Miquel Raynal
2022-06-20 0:13 ` Alexander Aring
2022-06-20 9:19 ` Miquel Raynal
2022-06-21 1:54 ` Alexander Aring [this message]
2022-06-21 6:27 ` Miquel Raynal
2022-06-26 1:36 ` Alexander Aring
2022-06-27 8:17 ` Miquel Raynal
2022-06-09 1:42 ` Alexander Aring
2022-06-09 14:42 ` Miquel Raynal
2022-06-03 18:21 ` [PATCH wpan-next 2/6] net: ieee802154: Add support for internal PAN management Miquel Raynal
2022-06-03 18:21 ` [PATCH wpan-next 3/6] net: ieee802154: Create a node type Miquel Raynal
2022-06-03 18:21 ` [PATCH wpan-next 4/6] net: ieee802154: Add the PAN coordinator information Miquel Raynal
2022-06-03 18:21 ` [PATCH wpan-next 5/6] net: ieee802154: Full PAN management Miquel Raynal
2022-06-03 18:21 ` [PATCH wpan-next 6/6] net: ieee802154: Trace the registration of new PANs Miquel Raynal
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAK-6q+jR00MD+W02AAH8P5xG7hUD-x8NEnOG_W3mifj=6ybBzg@mail.gmail.com' \
--to=aahringo@redhat.com \
--cc=alex.aring@gmail.com \
--cc=davem@davemloft.net \
--cc=david.girault@qorvo.com \
--cc=frederic.blain@qorvo.com \
--cc=kuba@kernel.org \
--cc=linux-wpan@vger.kernel.org \
--cc=miquel.raynal@bootlin.com \
--cc=netdev@vger.kernel.org \
--cc=nico@ni.fr.eu.org \
--cc=pabeni@redhat.com \
--cc=romuald.despres@qorvo.com \
--cc=stefan@datenfreihafen.org \
--cc=thomas.petazzoni@bootlin.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).