peer-discovery-mdns

Node.js libp2p mDNS discovery implementation for peer discovery

About

A peer discover mechanism that uses mDNS to discover peers on the local network.

Example

import { mdns } from '@libp2p/mdns'

const options = {
  peerDiscovery: [
    mdns()
  ]
}

const libp2p = await createLibp2p(options)

libp2p.on('peer:discovery', function (peerId) {
  console.log('found peer: ', peerId.toB58String())
})

await libp2p.start()

MDNS messages

A query is sent to discover the libp2p nodes on the local network

{
   type: 'query',
   questions: [ { name: '_p2p._udp.local', type: 'PTR' } ]
}

When a query is detected, each libp2p node sends an answer about itself

[{
  name: '_p2p._udp.local',
  type: 'PTR',
  class: 'IN',
  ttl: 120,
  data: 'QmNPubsDWATVngE3d5WDSNe7eVrFLuk38qb9t6vdLnu2aK._p2p._udp.local'
}, {
  name: 'QmNPubsDWATVngE3d5WDSNe7eVrFLuk38qb9t6vdLnu2aK._p2p._udp.local',
  type: 'SRV',
  class: 'IN',
  ttl: 120,
  data: {
    priority: 10,
    weight: 1,
    port: '20002',
    target: 'LAPTOP-G5LJ7VN9'
  }
}, {
  name: 'QmNPubsDWATVngE3d5WDSNe7eVrFLuk38qb9t6vdLnu2aK._p2p._udp.local',
  type: 'TXT',
  class: 'IN',
  ttl: 120,
  data: ['QmNPubsDWATVngE3d5WDSNe7eVrFLuk38qb9t6vdLnu2aK']
}, {
  name: 'LAPTOP-G5LJ7VN9',
  type: 'A',
  class: 'IN',
  ttl: 120,
  data: '127.0.0.1'
}, {
  name: 'LAPTOP-G5LJ7VN9',
  type: 'AAAA',
  class: 'IN',
  ttl: 120,
  data: '::1'
}]

Install

$ npm i @libp2p/mdns

API Docs

• https://libp2p.github.io/js-libp2p/modules/_libp2p_mdns.html

License

Licensed under either of

• Apache 2.0, (LICENSE-APACHE / http://www.apache.org/licenses/LICENSE-2.0)
• MIT (LICENSE-MIT / http://opensource.org/licenses/MIT)

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.