Support using systemd-resolved as mDNS responder

Current Situation

Homebridge currently supports three different mDNS advertisers, two that run in-process and one that uses Avahi over D-Bus. For a while now, systemd-resolved has supported acting as an mDNS advertiser and resolver. If Homebridge is run on a system that uses systemd-resolved for mDNS, this can cause conflicts similar to #3077.

Proposed Change

systemd-resolved, like Avahi, exposes a D-Bus interface for managing mDNS services. Ideally, Homebridge would have a systemd-resolved mDNS advertiser added that makes use of this interface.

Additional Context

A couple of RegisterService method’s arguments have slightly misleading names. From the documentation:

RegisterService(in  s name,
                in  s name_template,
                in  s type,
                in  q service_port,
                in  q service_priority,
                in  q service_weight,
                in  aa{say} txt_datas,
                out o service_path);

name here refers to the name the service should appear as in systemd. name_template is the actual server instance name, so called because it supports template expansion. Probably you’d want to set both name and name_template to the same value.

[elyscape]

Got it to work by adding "resolved" /* RESOLVED */, to lib/server.js.

Good catch. I’ll open a PR fixing this momentarily.

I also needed to convert homebridge.pkla as this format is deprecated in newer polkit versions.

Interesting. Can you point me at some documentation for this?

Update: found some. I’ll open another PR adding a .rules file.

[Supereg]

Thanks a lot for providing the updated Wiki descriptions 👍 . I updated the page accordingly.