feat: resolve multiaddrs before dial

Author: vasco-santos

doc/CONFIGURATION.md

@@ -465,6 +465,7 @@ Dialing in libp2p can be configured to limit the rate of dialing, and how long d
 | maxParallelDials | `number` | How many multiaddrs we can dial in parallel. |
 | maxDialsPerPeer | `number` | How many multiaddrs we can dial per peer, in parallel. |
 | dialTimeout | `number` | Second dial timeout per peer in ms. |
+| resolvers | `object` | Dial [Resolvers](https://github.com/multiformats/js-multiaddr/blob/master/src/resolvers/index.js) for resolving multiaddrs |
 
 The below configuration example shows how the dialer should be configured, with the current defaults:
 
@@ -474,6 +475,8 @@ const TCP = require('libp2p-tcp')
 const MPLEX = require('libp2p-mplex')
 const { NOISE } = require('libp2p-noise')
 
+const { dnsaddrResolver } = require('multiaddr/src/resolvers')
+
 const node = await Libp2p.create({
   modules: {
     transport: [TCP],
@@ -483,7 +486,10 @@ const node = await Libp2p.create({
   dialer: {
     maxParallelDials: 100,
     maxDialsPerPeer: 4,
-    dialTimeout: 30e3
+    dialTimeout: 30e3,
+    resolvers: {
+      dnsaddr: dnsaddrResolver
+    }
   }
 ```
 

package.json

@@ -64,7 +64,7 @@
     "mafmt": "^8.0.0",
     "merge-options": "^2.0.0",
     "moving-average": "^1.0.0",
-    "multiaddr": "^8.0.0",
+    "multiaddr": "multiformats/js-multiaddr#feat/resolve-multiaddrs",
     "multicodec": "^2.0.0",
     "multistream-select": "^1.0.0",
     "mutable-proxy": "^1.0.0",

src/config.js

@@ -1,6 +1,8 @@
 'use strict'
 
 const mergeOptions = require('merge-options')
+const { dnsaddrResolver } = require('multiaddr/src/resolvers')
+
 const Constants = require('./constants')
 
 const { FaultTolerance } = require('./transport-manager')
@@ -20,7 +22,10 @@ const DefaultConfig = {
   dialer: {
     maxParallelDials: Constants.MAX_PARALLEL_DIALS,
     maxDialsPerPeer: Constants.MAX_PER_PEER_DIALS,
-    dialTimeout: Constants.DIAL_TIMEOUT
+    dialTimeout: Constants.DIAL_TIMEOUT,
+    resolvers: {
+      dnsaddr: dnsaddrResolver
+    }
   },
   metrics: {
     enabled: false

src/dialer/index.js

@@ -18,6 +18,9 @@ const {
   MAX_PER_PEER_DIALS
 } = require('../constants')
 
+const dns4Code = 54
+const dns6Code = 55
+
 class Dialer {
   /**
    * @class
@@ -27,19 +30,22 @@ class Dialer {
    * @param {number} [options.concurrency = MAX_PARALLEL_DIALS] - Number of max concurrent dials.
    * @param {number} [options.perPeerLimit = MAX_PER_PEER_DIALS] - Number of max concurrent dials per peer.
    * @param {number} [options.timeout = DIAL_TIMEOUT] - How long a dial attempt is allowed to take.
+   * @param {object} [options.resolvers = {}]
    */
   constructor ({
     transportManager,
     peerStore,
     concurrency = MAX_PARALLEL_DIALS,
     timeout = DIAL_TIMEOUT,
-    perPeerLimit = MAX_PER_PEER_DIALS
+    perPeerLimit = MAX_PER_PEER_DIALS,
+    resolvers = {}
   }) {
     this.transportManager = transportManager
     this.peerStore = peerStore
     this.concurrency = concurrency
     this.timeout = timeout
     this.perPeerLimit = perPeerLimit
+    this.resolvers = resolvers
     this.tokens = [...new Array(concurrency)].map((_, index) => index)
     this._pendingDials = new Map()
   }
@@ -69,7 +75,7 @@ class Dialer {
    * @returns {Promise<Connection>}
    */
   async connectToPeer (peer, options = {}) {
-    const dialTarget = this._createDialTarget(peer)
+    const dialTarget = await this._createDialTarget(peer)
 
     if (!dialTarget.addrs.length) {
       throw errCode(new Error('The dial request has no addresses'), codes.ERR_NO_VALID_ADDRESSES)
@@ -105,22 +111,28 @@ class Dialer {
    *
    * @private
    * @param {PeerId|Multiaddr|string} peer - A PeerId or Multiaddr
-   * @returns {DialTarget}
+   * @returns {Promise<DialTarget>}
    */
-  _createDialTarget (peer) {
+  async _createDialTarget (peer) {
     const { id, multiaddrs } = getPeer(peer)
 
     if (multiaddrs) {
       this.peerStore.addressBook.add(id, multiaddrs)
     }
 
-    let addrs = this.peerStore.addressBook.getMultiaddrsForPeer(id) || []
+    let knownAddrs = this.peerStore.addressBook.getMultiaddrsForPeer(id) || []
 
     // If received a multiaddr to dial, it should be the first to use
     // But, if we know other multiaddrs for the peer, we should try them too.
     if (multiaddr.isMultiaddr(peer)) {
-      addrs = addrs.filter((addr) => !peer.equals(addr))
-      addrs.unshift(peer)
+      knownAddrs = knownAddrs.filter((addr) => !peer.equals(addr))
+      knownAddrs.unshift(peer)
+    }
+
+    const addrs = []
+    for (const a of knownAddrs) {
+      const resolvedAddrs = await this._resolve(a)
+      resolvedAddrs.forEach(ra => addrs.push(ra))
     }
 
     return {
@@ -190,6 +202,48 @@ class Dialer {
     log('token %d released', token)
     this.tokens.push(token)
   }
+
+  /**
+   * Resolve multiaddr recursively.
+   *
+   * @param {Multiaddr} ma
+   * @returns {Promise<Array<Multiaddr>>}
+   */
+  async _resolve (ma) {
+    // TODO: recursive logic should live in multiaddr once dns4/dns6 support is in place
+    const resolvableProto = ma.protos().find((p) => p.resolvable)
+
+    // Multiaddr is not resolvable (including exception for dns4/dns6)? End recursion!
+    if (!resolvableProto || resolvableProto.code === dns4Code || resolvableProto === dns6Code) {
+      return [ma]
+    }
+
+    const resolvedMultiaddrs = await this._resolveRecord(ma)
+    const recursiveMultiaddrs = await Promise.all(resolvedMultiaddrs.map((nm) => {
+      return this._resolve(nm)
+    }))
+
+    return recursiveMultiaddrs.flat().reduce((array, newM) => {
+      if (!array.find(m => m.equals(newM))) {
+        array.push(newM)
+      }
+      return array
+    }, []) // Unique addresses
+  }
+
+  /**
+   * Add dialer resolvers to multiaddr and resolve multiaddr.
+   *
+   * @param {Multiaddr} ma
+   * @returns {Promise<Array<Multiaddr>>}
+   */
+  _resolveRecord (ma) {
+    for (const [key, value] of Object.entries(this.resolvers)) {
+      ma.resolvers.set(key, value)
+    }
+
+    return ma.resolve()
+  }
 }
 
 module.exports = Dialer

src/index.js

@@ -134,7 +134,8 @@ class Libp2p extends EventEmitter {
       peerStore: this.peerStore,
       concurrency: this._options.dialer.maxParallelDials,
       perPeerLimit: this._options.dialer.maxDialsPerPeer,
-      timeout: this._options.dialer.dialTimeout
+      timeout: this._options.dialer.dialTimeout,
+      resolvers: this._options.dialer.resolvers
     })
 
     this._modules.transport.forEach((Transport) => {

test/dialing/direct.node.js

@@ -156,9 +156,9 @@ describe('Dialing (direct, TCP)', () => {
 
   it('should dial to the max concurrency', async () => {
     const addrs = [
-      '/ip4/0.0.0.0/tcp/8000',
-      '/ip4/0.0.0.0/tcp/8001',
-      '/ip4/0.0.0.0/tcp/8002'
+      multiaddr('/ip4/0.0.0.0/tcp/8000'),
+      multiaddr('/ip4/0.0.0.0/tcp/8001'),
+      multiaddr('/ip4/0.0.0.0/tcp/8002')
     ]
     const dialer = new Dialer({
       transportManager: localTM,

test/dialing/direct.spec.js

@@ -263,7 +263,7 @@ describe('Dialing (direct, WebSockets)', () => {
 
   describe('libp2p.dialer', () => {
     let libp2p
-    let remoteLibp2p
+    let remoteLibp2p // TODO rem
 
     afterEach(async () => {
       sinon.restore()

test/dialing/resolver.spec.js

@@ -0,0 +1,131 @@
+'use strict'
+/* eslint-env mocha */
+
+const { expect } = require('aegir/utils/chai')
+const sinon = require('sinon')
+
+const multiaddr = require('multiaddr')
+const { Resolver } = require('multiaddr/src/resolvers/dns')
+
+const peerUtils = require('../utils/creators/peer')
+const baseOptions = require('../utils/base-options.browser')
+
+const { MULTIADDRS_WEBSOCKETS } = require('../fixtures/browser')
+const relayAddr = MULTIADDRS_WEBSOCKETS[0]
+
+const getDnsaddrStub = (peerId) => [
+  [`dnsaddr=/dnsaddr/ams-1.bootstrap.libp2p.io/p2p/${peerId}`],
+  [`dnsaddr=/dnsaddr/ams-2.bootstrap.libp2p.io/p2p/${peerId}`],
+  [`dnsaddr=/dnsaddr/lon-1.bootstrap.libp2p.io/p2p/${peerId}`],
+  [`dnsaddr=/dnsaddr/nrt-1.bootstrap.libp2p.io/p2p/${peerId}`],
+  [`dnsaddr=/dnsaddr/nyc-1.bootstrap.libp2p.io/p2p/${peerId}`],
+  [`dnsaddr=/dnsaddr/sfo-2.bootstrap.libp2p.io/p2p/${peerId}`]
+]
+
+const relayedAddr = (peerId) => `${relayAddr}/p2p-circuit/p2p/${peerId}`
+
+const getDnsRelayedAddrStub = (peerId) => [
+  [`dnsaddr=${relayedAddr(peerId)}`]
+]
+
+describe('Dialing (resolvable addresses)', () => {
+  let libp2p, remoteLibp2p
+
+  beforeEach(async () => {
+    [libp2p, remoteLibp2p] = await peerUtils.createPeer({
+      number: 2,
+      config: {
+        modules: baseOptions.modules,
+        addresses: {
+          listen: [multiaddr(`${relayAddr}/p2p-circuit`)]
+        },
+        config: {
+          peerDiscovery: {
+            autoDial: false
+          }
+        }
+      },
+      started: true,
+      populateAddressBooks: false
+    })
+  })
+
+  afterEach(async () => {
+    sinon.restore()
+    await Promise.all([libp2p, remoteLibp2p].map(n => n.stop()))
+  })
+
+  it('resolves dnsaddr to ws local address', async () => {
+    const remoteId = remoteLibp2p.peerId.toB58String()
+    const dialAddr = multiaddr(`/dnsaddr/remote.libp2p.io/p2p/${remoteId}`)
+    const relayedAddrFetched = multiaddr(relayedAddr(remoteId))
+
+    // Transport spy
+    const transport = libp2p.transportManager._transports.get('Circuit')
+    sinon.spy(transport, 'dial')
+
+    // Resolver stub
+    const stub = sinon.stub(Resolver.prototype, 'resolveTxt')
+    stub.onCall(0).returns(Promise.resolve(getDnsRelayedAddrStub(remoteId)))
+
+    // Dial with address resolve
+    const connection = await libp2p.dial(dialAddr)
+    expect(connection).to.exist()
+    expect(connection.remoteAddr.equals(relayedAddrFetched))
+
+    const dialArgs = transport.dial.firstCall.args
+    expect(dialArgs[0].equals(relayedAddrFetched)).to.eql(true)
+  })
+
+  it('resolves a dnsaddr recursively', async () => {
+    const remoteId = remoteLibp2p.peerId.toB58String()
+    const dialAddr = multiaddr(`/dnsaddr/remote.libp2p.io/p2p/${remoteId}`)
+    const relayedAddrFetched = multiaddr(relayedAddr(remoteId))
+
+    // Transport spy
+    const transport = libp2p.transportManager._transports.get('Circuit')
+    sinon.spy(transport, 'dial')
+
+    // Resolver stub
+    const stub = sinon.stub(Resolver.prototype, 'resolveTxt')
+    let alreadyCalled = false
+    stub.callsFake(() => {
+      if (!alreadyCalled) {
+        alreadyCalled = true
+        // Return an array of dnsaddr
+        return Promise.resolve(getDnsaddrStub(remoteId))
+      }
+      return Promise.resolve(getDnsRelayedAddrStub(remoteId))
+    })
+
+    // Dial with address resolve
+    const connection = await libp2p.dial(dialAddr)
+    expect(connection).to.exist()
+    expect(connection.remoteAddr.equals(relayedAddrFetched))
+
+    const dialArgs = transport.dial.firstCall.args
+    expect(dialArgs[0].equals(relayedAddrFetched)).to.eql(true)
+  })
+
+  // TODO: Temporary solution does not resolve dns4/dns6
+  it('stops recursive resolve if finds dns4/dns6 and dials it', async () => {
+    const remoteId = remoteLibp2p.peerId.toB58String()
+    const dialAddr = multiaddr(`/dnsaddr/remote.libp2p.io/p2p/${remoteId}`)
+
+    // Stub resolver
+    const dnsMa = multiaddr(`/dns4/ams-1.remote.libp2p.io/tcp/443/wss/p2p/${remoteId}`)
+    const stubResolve = sinon.stub(Resolver.prototype, 'resolveTxt')
+    stubResolve.returns(Promise.resolve([
+      [`dnsaddr=${dnsMa}`]
+    ]))
+
+    // Stub transport
+    const transport = libp2p.transportManager._transports.get('WebSockets')
+    const stubTransport = sinon.stub(transport, 'dial')
+    stubTransport.callsFake((multiaddr) => {
+      expect(multiaddr.equals(dnsMa)).to.eql(true)
+    })
+
+    await libp2p.dial(dialAddr)
+  })
+})