feat: add autonat support (#1298)

Implements the [autonat](https://github.com/libp2p/specs/blob/master/autonat/README.md) spec to give us confidence in our external addresses and to open the door to things like switching DHT server mode on automatically, hole punching, v2 circuit relay etc.

Depends on:

- [x] libp2p/js-libp2p-interfaces#269

Fixes #1005

Author: achingbrain

package.json

@@ -79,11 +79,12 @@
   "scripts": {
     "clean": "aegir clean",
     "lint": "aegir lint",
-    "dep-check": "aegir dep-check",
+    "dep-check": "aegir dep-check -i protons",
     "prepublishOnly": "node scripts/update-version.js",
     "build": "aegir build",
     "docs": "aegir docs",
     "generate": "run-s generate:proto:*",
+    "generate:proto:autonat": "protons ./src/autonat/pb/index.proto",
     "generate:proto:circuit": "protons ./src/circuit/pb/index.proto",
     "generate:proto:fetch": "protons ./src/fetch/pb/proto.proto",
     "generate:proto:identify": "protons ./src/identify/pb/message.proto",
@@ -143,6 +144,7 @@
     "it-drain": "^2.0.0",
     "it-filter": "^2.0.0",
     "it-first": "^2.0.0",
+    "it-parallel": "^3.0.0",
     "it-handshake": "^4.1.2",
     "it-length-prefixed": "^8.0.2",
     "it-map": "^2.0.0",
@@ -201,6 +203,7 @@
     "p-event": "^5.0.1",
     "p-times": "^4.0.0",
     "p-wait-for": "^5.0.0",
+    "protons": "^7.0.2",
     "sinon": "^15.0.1",
     "sinon-ts": "^1.0.0"
   },

src/address-manager/index.ts

@@ -44,12 +44,35 @@ export interface AddressFilter {
 
 const defaultAddressFilter = (addrs: Multiaddr[]): Multiaddr[] => addrs
 
+interface ObservedAddressMetadata {
+  confident: boolean
+}
+
+/**
+ * If the passed multiaddr contains the passed peer id, remove it
+ */
+function stripPeerId (ma: Multiaddr, peerId: PeerId): Multiaddr {
+  const observedPeerIdStr = ma.getPeerId()
+
+  // strip our peer id if it has been passed
+  if (observedPeerIdStr != null) {
+    const observedPeerId = peerIdFromString(observedPeerIdStr)
+
+    // use same encoding for comparison
+    if (observedPeerId.equals(peerId)) {
+      ma = ma.decapsulate(multiaddr(`/p2p/${peerId.toString()}`))
+    }
+  }
+
+  return ma
+}
+
 export class DefaultAddressManager extends EventEmitter<AddressManagerEvents> {
   private readonly components: DefaultAddressManagerComponents
   // this is an array to allow for duplicates, e.g. multiples of `/ip4/0.0.0.0/tcp/0`
   private readonly listen: string[]
   private readonly announce: Set<string>
-  private readonly observed: Set<string>
+  private readonly observed: Map<string, ObservedAddressMetadata>
   private readonly announceFilter: AddressFilter
 
   /**
@@ -66,7 +89,7 @@ export class DefaultAddressManager extends EventEmitter<AddressManagerEvents> {
     this.components = components
     this.listen = listen.map(ma => ma.toString())
     this.announce = new Set(announce.map(ma => ma.toString()))
-    this.observed = new Set()
+    this.observed = new Map()
     this.announceFilter = init.announceFilter ?? defaultAddressFilter
   }
 
@@ -88,52 +111,51 @@ export class DefaultAddressManager extends EventEmitter<AddressManagerEvents> {
    * Get observed multiaddrs
    */
   getObservedAddrs (): Multiaddr[] {
-    return Array.from(this.observed).map((a) => multiaddr(a))
+    return Array.from(this.observed).map(([a]) => multiaddr(a))
   }
 
   /**
    * Add peer observed addresses
-   * Signal that we have confidence an observed multiaddr is publicly dialable -
-   * this will make it appear in the output of getAddresses()
    */
-  confirmObservedAddr (addr: Multiaddr): void {
-
-  }
+  addObservedAddr (addr: Multiaddr): void {
+    addr = stripPeerId(addr, this.components.peerId)
+    const addrString = addr.toString()
 
-  /**
-   * Signal that we do not have confidence an observed multiaddr is publicly dialable -
-   * this will remove it from the output of getObservedAddrs()
-   */
-  removeObservedAddr (addr: Multiaddr): void {
+    // do not trigger the change:addresses event if we already know about this address
+    if (this.observed.has(addrString)) {
+      return
+    }
 
+    this.observed.set(addrString, {
+      confident: false
+    })
   }
 
-  /**
-   * Add peer observed addresses
-   */
-  addObservedAddr (addr: string | Multiaddr): void {
-    let ma = multiaddr(addr)
-    const remotePeer = ma.getPeerId()
-
-    // strip our peer id if it has been passed
-    if (remotePeer != null) {
-      const remotePeerId = peerIdFromString(remotePeer)
-
-      // use same encoding for comparison
-      if (remotePeerId.equals(this.components.peerId)) {
-        ma = ma.decapsulate(multiaddr(`/p2p/${this.components.peerId.toString()}`))
-      }
+  confirmObservedAddr (addr: Multiaddr): void {
+    addr = stripPeerId(addr, this.components.peerId)
+    const addrString = addr.toString()
+
+    const metadata = this.observed.get(addrString) ?? {
+      confident: false
     }
 
-    const addrString = ma.toString()
+    const startingConfidence = metadata.confident
 
-    // do not trigger the change:addresses event if we already know about this address
-    if (this.observed.has(addrString)) {
-      return
+    this.observed.set(addrString, {
+      confident: true
+    })
+
+    // only trigger the change:addresses event if our confidence in an address has changed
+    if (!startingConfidence) {
+      this.dispatchEvent(new CustomEvent('change:addresses'))
     }
+  }
+
+  removeObservedAddr (addr: Multiaddr): void {
+    addr = stripPeerId(addr, this.components.peerId)
+    const addrString = addr.toString()
 
-    this.observed.add(addrString)
-    this.dispatchEvent(new CustomEvent('change:addresses'))
+    this.observed.delete(addrString)
   }
 
   getAddresses (): Multiaddr[] {
@@ -144,7 +166,12 @@ export class DefaultAddressManager extends EventEmitter<AddressManagerEvents> {
       addrs = this.components.transportManager.getAddrs().map(ma => ma.toString())
     }
 
-    addrs = addrs.concat(this.getObservedAddrs().map(ma => ma.toString()))
+    // add observed addresses we are confident in
+    addrs = addrs.concat(
+      Array.from(this.observed)
+        .filter(([ma, metadata]) => metadata.confident)
+        .map(([ma]) => ma)
+    )
 
     // dedupe multiaddrs
     const addrSet = new Set(addrs)

src/autonat/constants.ts

@@ -0,0 +1,4 @@
+
+export const PROTOCOL = '/libp2p/autonat/1.0.0'
+export const PROTOCOL_VERSION = '1.0.0'
+export const PROTOCOL_NAME = 'autonat'