vfs_fruit: Time Machine/FULLSYNC: add mDNS/DNS-SD advertisement

[Ralph Böhme]

On Wed, Jul 19, 2017 at 11:25:58PM -0700, Omri Mor wrote:
> > On Jul 19, 2017, at 20:46, Ralph Böhme <slow at samba.org> wrote:
> > 
> > I don't quite remember the details, but iirc we just added adVU support to
> > Netatalk to behave exactly like a OS X (back then) server. If it does work without a adVU or
> > a fake one that might be ok, but lacking clear documentation and spec I guess
> > the safest approach is still to behave exactly like a macOS server.
> > 
> > Cheerio!
> > -slow
> 
> > On Jul 19, 2017, at 21:01, Ralph Böhme <slow at samba.org> wrote:
> > 
> > Please document your findings. We could add it to our Wiki.
> 
> As per the Time Machine over SMB specification, 0x0002 in adVF
> (AirDiskVolumeFlags) means "SMB is supported on this volume”. The wiki
> currently lists that as “unknown”.

updated.

> The wiki also has adVU attached to the sys key, while other sources (and
> Netatalk itself, if I recall correctly) use it in dkN.

Hm, that's probably a mistake in the documentation. I've changed it by moving
the adVU key to the disk registration.

I was more thinking about adding a similar, up2date page documenting the records
as relevant to TM over SMB to the Samba wiki.

> I’ve seen sources with the adVU UUID using both uppercase and lowercase
> versions—I don’t think it matters, as it should be interpreted as hexadecimal
> in any case. I just used a randomly generated UUID.

In Netatalk we generate a UUID per TM share when and store it pesistently. We
could do the same in Samba. The simplest thing would be stroring share-name =>
UUID records in gencache. But that will probably lead to problems when users
flush the cache with `net cache flush`.

> I don’t have macOS Server, so I can’t verify what it uses—my understanding is
> that it’s primarily a GUI to the underlying system services, which can be used
> on their own, though they need to be manually set-up.

I have a system somewhere, if you tell me what to test exactly I could do that.

> It seems that only macOS Server uses the 0x0020 flag, with some sources saying
> that Time Capsules don’t.
>
> There’s also a 0x1000 flag that’s undocumented, but it’s been less commonly
> used in the wild. It has appeared in both the sys and the dkN keys.  The
> 0x0100 flag has only ever appeared (and has any effect) in the sys key. 0x0010
> has appeared in both.
> 
> I don’t suppose Apple would give us some documentation if we asked them really
> nicely?

We could ask. :) We could also file a bugreport.

Cheerio!
-slow