From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Young Subject: Re: [RFA] TLV fields for radiotap Date: Mon, 17 Dec 2018 20:05:26 -0600 Message-ID: <20181218020526.GH27633@pobox.com> References: <1531126034.3298.18.camel@sipsolutions.net> <1536063298.3940.12.camel@sipsolutions.net> <81658b7a400e6189c55587c8276d5555b6fe37f0.camel@sipsolutions.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <81658b7a400e6189c55587c8276d5555b6fe37f0.camel-cdvu00un1VgdHxzADdlk8Q@public.gmane.org> Sender: radiotap-owner-sUITvd46vNxg9hUCZPvPmw@public.gmane.org List-Unsubscribe: To: radiotap-S783fYmB3Ccdnm+yROfE0A@public.gmane.org List-Id: radiotap@radiotap.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