Re: [PATCH net-next] net: appletalk: remove Apple/Farallon LocalTalk PC support

Re: [PATCH net-next] net: appletalk: remove Apple/Farallon LocalTalk PC support

[Arnd Bergmann]

On Wed, May 11, 2022 at 2:20 AM Doug Brown <doug@schmorgal.com> wrote:
>
> On 5/9/2022 11:48 PM, Arnd Bergmann wrote:
> > If I understand this correct, this means we could remove all of
> > drivers/net/appletalk/ except for the CONFIG_ATALK Kconfig entry,
> > and also remove net/appletalk/dev.c and a few bits of net/appletalk
> > that reference localtalk device structures and their ioctls, right?
> Yes, I believe so. At that point, would Kconfig get moved to
> net/appletalk instead? (Just wondering out of my own curiosity!)
> > What about appletalk over PPP (phase1 probing in aarp.c) and
> > ARPHRD_LOCALTLK support in drivers/net/tun.c? Are these still
> > useful without localtalk device support?
>
> I don't feel qualified enough to answer those ones definitively, but it
> looks to me like the ARPHRD_LOCALTLK support in net/tun.c could be
> stripped out, because tun_get_addr_len only gets called on a struct
> net_device's type, and stripping out LocalTalk would make that condition
> impossible (I think?)

Right, I came to the same conclusion here.

> The AppleTalk over PPP stuff probably allows Linux to be an AppleTalk
> Remote Access server. I'm not aware of anyone using that capability, (or
> if it even still works) but I would consider it distinct from LocalTalk.

I dug around in the early git history for this one, but I'm also not
sure if this is meant to still work. I see that PPPTALK support was added
to net/appletalk by Alan Cox in linux-1.3.78 (1996), based on the localtalk
support, and it continues to exist there along ethertalk and localtalk.

I also looked at the git history for the pppd user space, and I find no
indication of appletalk ever being supported there, this all looks
IPv4/IPv6 specific. There was support for PPP_IPX until it was
dropped this year (the kernel side got removed in 2018), but never
for PPP_AT.
Adding Paul Mackerras to Cc, he might know more about it.

> I would definitely be happy to test any patches to make sure that
> EtherTalk still works with netatalk afterward!

       Arnd

Re: [PATCH net-next] net: appletalk: remove Apple/Farallon LocalTalk PC support

[James Carlson]

On 5/11/22 04:23, Arnd Bergmann wrote:
> indication of appletalk ever being supported there, this all looks
> IPv4/IPv6 specific. There was support for PPP_IPX until it was
> dropped this year (the kernel side got removed in 2018), but never
> for PPP_AT.
> Adding Paul Mackerras to Cc, he might know more about it.

I waited a bit before chipping in, as I think Paul would know more.

The ATCP stuff was in at least a few vendor branches, but I don't think
it ever made it into the main distribution. These commits seem to be
where the (disabled by default) references to it first appeared:

commit 50c9469f0f683c7bf8ebad9b7f97bfc03c6a4122
Author: Paul Mackerras <paulus@samba.org>
Date:   Tue Mar 4 03:32:37 1997 +0000

    add defs for appletalk

commit 01548ef15e0f41f9f6af33860fb459a7f578f004
Author: Paul Mackerras <paulus@samba.org>
Date:   Tue Mar 4 03:41:17 1997 +0000

    connect time stuff gone to auth.c,
    don't die on EINTR from opening tty,
    ignore NCP packets during authentication,
    fix recursive signal problem in kill_my_pg

The disabled-by-default parts were likely support contributions for
those other distributions. (Very likely in BSD.)

I would've thought AppleTalk was completely gone by now, and I certainly
would not be sad to see the dregs removed from pppd, but there was a
patch release on the netatalk package just last month, so what do I know?

(The only possible reason I can see to keep any ATCP bits around at all
is to make sure we can write nice-looking log messages -- to say we're
rejecting "AppleTalk Control Protocol" rather than "unknown 8029." But
that'd be a very minor feature.)

-- 
James Carlson     42.703N 71.076W FN42lq08    <carlsonj@workingcode.com>

Re: [PATCH net-next] net: appletalk: remove Apple/Farallon LocalTalk PC support

[Arnd Bergmann]

On Thu, May 12, 2022 at 8:11 PM James Carlson <carlsonj@workingcode.com> wrote:
>
> On 5/11/22 04:23, Arnd Bergmann wrote:
> > indication of appletalk ever being supported there, this all looks
> > IPv4/IPv6 specific. There was support for PPP_IPX until it was
> > dropped this year (the kernel side got removed in 2018), but never
> > for PPP_AT.
> > Adding Paul Mackerras to Cc, he might know more about it.
>
> I waited a bit before chipping in, as I think Paul would know more.
>
> The ATCP stuff was in at least a few vendor branches, but I don't think
> it ever made it into the main distribution. These commits seem to be
> where the (disabled by default) references to it first appeared:
>
> commit 50c9469f0f683c7bf8ebad9b7f97bfc03c6a4122
> Author: Paul Mackerras <paulus@samba.org>
> Date:   Tue Mar 4 03:32:37 1997 +0000
>
>     add defs for appletalk
>
> commit 01548ef15e0f41f9f6af33860fb459a7f578f004
> Author: Paul Mackerras <paulus@samba.org>
> Date:   Tue Mar 4 03:41:17 1997 +0000
>
>     connect time stuff gone to auth.c,
>     don't die on EINTR from opening tty,
>     ignore NCP packets during authentication,
>     fix recursive signal problem in kill_my_pg

Right, I had seen those in the git history, but neither of them actually
does anything with appletak.

> The disabled-by-default parts were likely support contributions for
> those other distributions. (Very likely in BSD.)
>
> I would've thought AppleTalk was completely gone by now, and I certainly
> would not be sad to see the dregs removed from pppd, but there was a
> patch release on the netatalk package just last month, so what do I know?

I think netatalk 3.0 dropped all appletalk protocol stuff a long time ago and
only supports AFP over IP.

         Arnd

Re: [PATCH net-next] net: appletalk: remove Apple/Farallon LocalTalk PC support

[Doug Brown]

On 5/12/2022 12:21 PM, Arnd Bergmann wrote:
> On Thu, May 12, 2022 at 8:11 PM James Carlson <carlsonj@workingcode.com> wrote:
>>
>> I would've thought AppleTalk was completely gone by now, and I certainly
>> would not be sad to see the dregs removed from pppd, but there was a
>> patch release on the netatalk package just last month, so what do I know?
> 
> I think netatalk 3.0 dropped all appletalk protocol stuff a long time ago and
> only supports AFP over IP.
That's right. The older netatalk 2.x branch has a few different branches 
on GitHub that are being maintained to allow AppleTalk connectivity with 
older Macs through Ethernet (or LocalTalk-to-Ethernet bridges), so 
people are still actively using AppleTalk with Ethernet.

BTW, I messed up my quoting in my previous message so it was hard to see 
part of my reply -- but I agree that everything in drivers/net/appletalk 
could go away except for the Kconfig entry for CONFIG_ATALK. And dev.c 
and the other LocalTalk-specific bits in net/appletalk could go away.