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From: David Young <dyoung-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>
To: radiotap-S783fYmB3Ccdnm+yROfE0A@public.gmane.org
Subject: Re: [RFA] TLV fields for radiotap
Date: Mon, 17 Dec 2018 20:05:26 -0600
Message-ID: <20181218020526.GH27633@pobox.com> (raw)
In-Reply-To: <81658b7a400e6189c55587c8276d5555b6fe37f0.camel-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>

On Tue, Nov 20, 2018 at 09:09:39PM +0100, Johannes Berg wrote:
> On Tue, 2018-09-04 at 14:14 +0200, Johannes Berg wrote:
> > On Mon, 2018-07-09 at 10:47 +0200, Johannes Berg wrote:
> > > Since there were no comments, let's make this more formal. Any
> > > objections now?
> > 
> > Does this look like a good idea/compromise?
> > 
> > It's hard to do an entirely new version, then at least in Linux we'd
> > probably have to be able to switch versions on the fly for some time,
> > which is awkward ... but OTOH this feels a bit hackish.
> > 
> > No comments at all? :)
> 
> *crickets*

Sorry, I keep meaning to but forgetting to respond to this.

I had a thought about this tonight: maybe the solution is to define
a new radiotap field, "hint," that contains a hint about the offset
to a field.  The field begins with a 16-bit (?) field number, f, to
be interpreted in the current namespace.  Following that is a 16-bit
(?) absolute offset from the end of the hint field to field f.  If you
introduce your vendor namespace when the last-assigned presence bit is
bit p, and later you reuse the vendor namespace with newly-assigned
presence bit p+k, then you can supply a hint for the vendor namespace
field so that old readers can still benefit from presence bits 0..p and
your vendor fields.

Anyway, I've only just thought-up the hint field, so I am not even sure
that it's well-defined.

Dave

-- 
David Young
dyoung-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org    Urbana, IL    (217) 721-9981

  parent reply index

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-09  8:47 Johannes Berg
     [not found] ` <1531126034.3298.18.camel-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
2018-09-04 12:14   ` Johannes Berg
     [not found]     ` <1536063298.3940.12.camel-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
2018-11-20 20:09       ` Johannes Berg
     [not found]         ` <81658b7a400e6189c55587c8276d5555b6fe37f0.camel-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
2018-12-18  2:05           ` David Young [this message]
     [not found]             ` <20181218020526.GH27633-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>
2018-12-18 13:45               ` Johannes Berg
     [not found]                 ` <2c771c875d88d51d1cd98023686f084a5b6486bc.camel-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
2019-04-09  8:38                   ` Johannes Berg
2019-04-09  8:51 Johannes Berg

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