[zeromq-dev] Relicensing completion and feature removal, need clean-room reimplementations of zmq_proxy_steerable() and ZMQ_RECONNECT_IVL_MAX

[Luca Boccassi]

On Mon, 5 Jun 2023 at 12:49, Luca Boccassi <bluca at debian.org> wrote:
>
> Hi,
>
> As you might or might not be aware, we have been working hard for years
> to complete the libzmq relicensing effort that Pieter started long ago,
> from LGPL3+exceptions to standard MPL2:
>
> https://github.com/zeromq/libzmq/issues/2376
>
> After a lot of work, we are down to only 3 grants missing, covering the
> following:
>
> - tweetnacl integration as alternative to libsodium (relicensing
> NACKed)
> - zmq_proxy_steerable() (no answer)
> - ZMQ_RECONNECT_IVL_MAX (no answer)
>
> We have been waiting for years, with many requests without responses
> for the latter two, and it doesn't make sense to wait anymore.
>
> So with this PR the above functionality will simply be removed:
>
> https://github.com/zeromq/libzmq/pull/4554
>
> I will merge it later today.
>
> Tweetnacl is really not a problem, it was always intended as a local-
> only thing to facilitate zmq_curve development, which is long done. The
> only supported production encryption implementation is libsodium, which
> is available everywhere, so I do not intend to put tweetnacl
> integration back. If anybody was using curve+tweetnacl in a production
> setting, they were doing something _very_ wrong and need to stop asap
> anyway. It's a footgun and it's best to be rid of it.
>
> The other two are more problematic, as they are public APIs. The PR
> changes them to be empty stubs that return EOPNOTSUPP (so that ABI
> doesn't change). But I will make at least an attempt to get a
> reimplementation so:
>
> If you are able to, and you have NEVER LOOKED AT THE PREVIOUS
> IMPLEMENTATIONS (I will require you to state this explicitly in the
> commit messages), please consider helping out and reimplementing these
> two APIs, based solely on the public documentation:
>
> http://api.zeromq.org/4-3:zmq-proxy-steerable
> http://api.zeromq.org/4-3:zmq-setsockopt#:~:text=connection%2Doriented%20transports-,ZMQ_RECONNECT_IVL_MAX,-%3A%20Set%20maximum%20reconnection
>
> I cannot stress this enough, it must be a clean-room reimplementation
> so no prior knowledge of the previous implementation details nor
> looking at the previos implementation is allowed (hence why I cannot do
> it myself).
>
> If you are able to help, please speak up. These are not difficult to
> add, especially the socket option should be very straightforward. I
> will of course be able to review and provide guidance.
>
> After merging the above PR I will complete the relicensing shortly
> after, taking advantage of the switch to also use the standard SPDX
> format in source files. The relicense grants will be moved to:
> https://github.com/rlenferink/libzmq-relicense
> for archival.

ZMQ_RECONNECT_IVL_MAX has been contributed back by Stéphane Valès
(thanks!). Any takers for zmq_proxy_steerable() ?