Multicast DNS API

[lidel]

Summary

A WebExtension API to provide Multicast DNS functionality

It could be implemented on top of raw UDP socket API (#12), but because it is much safer for browser vendors to implement mDNS API alone, it may happen before we get raw socket API.

Motivation

If we are able to make it work in browser, it would be a huge win all distributed protocols.

Status

Browsers

• Mozilla
  • Prior art: FlyWeb
  • Bug 1461830 - mDNS APIs for local network discoverability for IoT and p2p extensions
  • Discussing Experimental APIs for Firefox WebExtensions: DNS-SD API DNS-SD API mozilla/libdweb#7
• Chrome
  • Prior art: mdns API (limited to Chrome Apps)

Protocols

• IPFS
  • MulticastDNS is already supported by js-ipfs/libp2p for local network discoverability, but only works in Node and is not compatible with DNS-SD.
  • We are working toward being compliant with DNS-SD spec, so we can use mDNS API from mozilla/libdweb and get LAN discovery in webextension
    • Future of mDNS discovery: Future of mDNS discovery libp2p/libp2p#28, [RFC] peer discovery with mDNS libp2p/specs#80

[daviddias]

An exciting update that is very worth sharing in this thread. The first demo of js-ipfs using MulticastDNS on a Web Extension thanks to libdweb!

Announcement: https://twitter.com/_alanshaw/status/1027296652594499584
Video Demo: https://www.youtube.com/watch?v=FRzyWUXIyeo

👏🏽👏🏽👏🏽 to @alanshaw and everyone that contributed to make this possible!

[rektide]

Two pieces of prior art I'll tack on:

The Network Discovery Specification used to have a means of doing MDNS discovery. It also did SSDP (which UPnP advertises on) and DIAL. No ability to publish services, but an interesting feature.
https://www.w3.org/TR/2014/WD-discovery-api-20140220/

Opera's Unite also described a Service Discovery system. I was never sure exactly what it was or how it worked but there's a model here, of devices & service descriptions.
https://github.com/operasoftware/unite-libraries/tree/master/service-discovery-api