feat: add circuit v2 subprotocols

src/circuit/auto-relay.js

@@ -0,0 +1,302 @@
+'use strict'
+
+const debug = require('debug')
+const log = Object.assign(debug('libp2p:auto-relay'), {
+  error: debug('libp2p:auto-relay:err')
+})
+
+const { fromString: uint8ArrayFromString } = require('uint8arrays/from-string')
+const { toString: uint8ArrayToString } = require('uint8arrays/to-string')
+const { Multiaddr } = require('multiaddr')
+const all = require('it-all')
+
+const { relayV1: multicodec } = require('./multicodec')
+const { canHop } = require('./v1/hop')
+const { namespaceToCid } = require('./utils')
+const {
+  CIRCUIT_PROTO_CODE,
+  HOP_METADATA_KEY,
+  HOP_METADATA_VALUE,
+  RELAY_RENDEZVOUS_NS
+} = require('./constants')
+
+/**
+ * @typedef {import('libp2p-interfaces/src/connection').Connection} Connection
+ * @typedef {import('../peer-store/types').Address} Address
+ * @typedef {import('peer-id')} PeerId
+ */
+
+/**
+ * @typedef {Object} AutoRelayProperties
+ * @property {import('../')} libp2p
+ *
+ * @typedef {Object} AutoRelayOptions
+ * @property {number} [maxListeners = 1] - maximum number of relays to listen.
+ * @property {(error: Error, msg?: string) => {}} [onError]
+ */
+
+class AutoRelay {
+  /**
+   * Creates an instance of AutoRelay.
+   *
+   * @class
+   * @param {AutoRelayProperties & AutoRelayOptions} props
+   */
+  constructor ({ libp2p, maxListeners = 1, onError }) {
+    this._libp2p = libp2p
+    this._peerId = libp2p.peerId
+    this._peerStore = libp2p.peerStore
+    this._connectionManager = libp2p.connectionManager
+    this._transportManager = libp2p.transportManager
+    this._addressSorter = libp2p.dialer.addressSorter
+
+    this.maxListeners = maxListeners
+
+    /**
+     * @type {Set<string>}
+     */
+    this._listenRelays = new Set()
+
+    this._onProtocolChange = this._onProtocolChange.bind(this)
+    this._onPeerDisconnected = this._onPeerDisconnected.bind(this)
+
+    this._peerStore.on('change:protocols', this._onProtocolChange)
+    this._connectionManager.on('peer:disconnect', this._onPeerDisconnected)
+
+    /**
+     * @param {Error} error
+     * @param {string} [msg]
+     */
+    this._onError = (error, msg) => {
+      log.error(msg || error)
+      onError && onError(error, msg)
+    }
+  }
+
+  /**
+   * Check if a peer supports the relay protocol.
+   * If the protocol is not supported, check if it was supported before and remove it as a listen relay.
+   * If the protocol is supported, check if the peer supports **HOP** and add it as a listener if
+   * inside the threshold.
+   *
+   * @param {Object} props
+   * @param {PeerId} props.peerId
+   * @param {string[]} props.protocols
+   * @returns {Promise<void>}
+   */
+  async _onProtocolChange ({ peerId, protocols }) {
+    const id = peerId.toB58String()
+
+    // Check if it has the protocol
+    const hasProtocol = protocols.find(protocol => protocol === multicodec)
+
+    // If no protocol, check if we were keeping the peer before as a listenRelay
+    if (!hasProtocol && this._listenRelays.has(id)) {
+      await this._removeListenRelay(id)
+      return
+    } else if (!hasProtocol || this._listenRelays.has(id)) {
+      return
+    }
+
+    // If protocol, check if can hop, store info in the metadataBook and listen on it
+    try {
+      const connection = this._connectionManager.get(peerId)
+      if (!connection) {
+        return
+      }
+
+      // Do not hop on a relayed connection
+      if (connection.remoteAddr.protoCodes().includes(CIRCUIT_PROTO_CODE)) {
+        log(`relayed connection to ${id} will not be used to hop on`)
+        return
+      }
+
+      const supportsHop = await canHop({ connection })
+
+      if (supportsHop) {
+        await this._peerStore.metadataBook.setValue(peerId, HOP_METADATA_KEY, uint8ArrayFromString(HOP_METADATA_VALUE))
+        await this._addListenRelay(connection, id)
+      }
+    } catch (/** @type {any} */ err) {
+      this._onError(err)
+    }
+  }
+
+  /**
+   * Peer disconnects.
+   *
+   * @param {Connection} connection - connection to the peer
+   */
+  _onPeerDisconnected (connection) {
+    const peerId = connection.remotePeer
+    const id = peerId.toB58String()
+
+    // Not listening on this relay
+    if (!this._listenRelays.has(id)) {
+      return
+    }
+
+    this._removeListenRelay(id).catch(err => {
+      log.error(err)
+    })
+  }
+
+  /**
+   * Attempt to listen on the given relay connection.
+   *
+   * @private
+   * @param {Connection} connection - connection to the peer
+   * @param {string} id - peer identifier string
+   * @returns {Promise<void>}
+   */
+  async _addListenRelay (connection, id) {
+    try {
+      // Check if already listening on enough relays
+      if (this._listenRelays.size >= this.maxListeners) {
+        return
+      }
+
+      // Get peer known addresses and sort them per public addresses first
+      const remoteAddrs = await this._peerStore.addressBook.getMultiaddrsForPeer(
+        connection.remotePeer, this._addressSorter
+      )
+
+      // Attempt to listen on relay
+      const result = await Promise.all(
+        remoteAddrs.map(async addr => {
+          try {
+            // Announce multiaddrs will update on listen success by TransportManager event being triggered
+            await this._transportManager.listen([new Multiaddr(`${addr.toString()}/p2p-circuit`)])
+            return true
+          } catch (/** @type {any} */ err) {
+            this._onError(err)
+          }
+
+          return false
+        })
+      )
+
+      if (result.includes(true)) {
+        this._listenRelays.add(id)
+      }
+    } catch (/** @type {any} */ err) {
+      this._onError(err)
+      this._listenRelays.delete(id)
+    }
+  }
+
+  /**
+   * Remove listen relay.
+   *
+   * @private
+   * @param {string} id - peer identifier string.
+   */
+  async _removeListenRelay (id) {
+    if (this._listenRelays.delete(id)) {
+      // TODO: this should be responsibility of the connMgr
+      await this._listenOnAvailableHopRelays([id])
+    }
+  }
+
+  /**
+   * Try to listen on available hop relay connections.
+   * The following order will happen while we do not have enough relays.
+   * 1. Check the metadata store for known relays, try to listen on the ones we are already connected.
+   * 2. Dial and try to listen on the peers we know that support hop but are not connected.
+   * 3. Search the network.
+   *
+   * @param {string[]} [peersToIgnore]
+   */
+  async _listenOnAvailableHopRelays (peersToIgnore = []) {
+    // TODO: The peer redial issue on disconnect should be handled by connection gating
+    // Check if already listening on enough relays
+    if (this._listenRelays.size >= this.maxListeners) {
+      return
+    }
+
+    const knownHopsToDial = []
+    const peers = await all(this._peerStore.getPeers())
+
+    // Check if we have known hop peers to use and attempt to listen on the already connected
+    for await (const { id, metadata } of peers) {
+      const idStr = id.toB58String()
+
+      // Continue to next if listening on this or peer to ignore
+      if (this._listenRelays.has(idStr)) {
+        continue
+      }
+
+      if (peersToIgnore.includes(idStr)) {
+        continue
+      }
+
+      const supportsHop = metadata.get(HOP_METADATA_KEY)
+
+      // Continue to next if it does not support Hop
+      if (!supportsHop || uint8ArrayToString(supportsHop) !== HOP_METADATA_VALUE) {
+        continue
+      }
+
+      const connection = this._connectionManager.get(id)
+
+      // If not connected, store for possible later use.
+      if (!connection) {
+        knownHopsToDial.push(id)
+        continue
+      }
+
+      await this._addListenRelay(connection, idStr)
+
+      // Check if already listening on enough relays
+      if (this._listenRelays.size >= this.maxListeners) {
+        return
+      }
+    }
+
+    // Try to listen on known peers that are not connected
+    for (const peerId of knownHopsToDial) {
+      await this._tryToListenOnRelay(peerId)
+
+      // Check if already listening on enough relays
+      if (this._listenRelays.size >= this.maxListeners) {
+        return
+      }
+    }
+
+    // Try to find relays to hop on the network
+    try {
+      const cid = await namespaceToCid(RELAY_RENDEZVOUS_NS)
+      for await (const provider of this._libp2p.contentRouting.findProviders(cid)) {
+        if (!provider.multiaddrs.length) {
+          continue
+        }
+
+        const peerId = provider.id
+        await this._peerStore.addressBook.add(peerId, provider.multiaddrs)
+
+        await this._tryToListenOnRelay(peerId)
+
+        // Check if already listening on enough relays
+        if (this._listenRelays.size >= this.maxListeners) {
+          return
+        }
+      }
+    } catch (/** @type {any} */ err) {
+      this._onError(err)
+    }
+  }
+
+  /**
+   * @param {PeerId} peerId
+   */
+  async _tryToListenOnRelay (peerId) {
+    try {
+      const connection = await this._libp2p.dial(peerId)
+      await this._addListenRelay(connection, peerId.toB58String())
+    } catch (/** @type {any} */ err) {
+      this._onError(err, `could not connect and listen on known hop relay ${peerId.toB58String()}`)
+    }
+  }
+}
+
+module.exports = AutoRelay

src/circuit/multicodec.js

@@ -0,0 +1,7 @@
+'use strict'
+
+module.exports = {
+  relayV1: '/libp2p/circuit/relay/0.1.0',
+  protocolIDv2Hop: '/libp2p/circuit/relay/0.2.0/hop',
+  protocolIDv2Stop: '/libp2p/circuit/relay/0.2.0/stop'
+}