feat: support custom listener options (#822)

* support custom listener options

* fix get listener options

* add doc to explain custom listener options

* add ut

* fix code style

* Apply suggestions from code review

Co-authored-by: Vasco Santos <vasco.santos@ua.pt>

* add missing comma

Co-authored-by: Vasco Santos <vasco.santos@ua.pt>

doc/CONFIGURATION.md

@@ -651,6 +651,35 @@ const node = await Libp2p.create({
 })
 ```
 
+During Libp2p startup, transport listeners will be created for the configured listen multiaddrs.  Some transports support custom listener options and you can set them using the `listenerOptions` in the transport configuration. For example, [libp2p-webrtc-star](https://github.com/libp2p/js-libp2p-webrtc-star) transport listener supports the configuration of its underlying [simple-peer](https://github.com/feross/simple-peer) ice server(STUN/TURN) config as follows:
+
+```js
+const transportKey = WebRTCStar.prototype[Symbol.toStringTag]
+const node = await Libp2p.create({
+  modules: {
+    transport: [WebRTCStar],
+    streamMuxer: [MPLEX],
+    connEncryption: [NOISE]
+  },
+  addresses: {
+    listen: ['/dns4/your-wrtc-star.pub/tcp/443/wss/p2p-webrtc-star'] // your webrtc dns multiaddr
+  },
+  config: {
+    transport: {
+      [transportKey]: {
+        listenerOptions: {
+          config: {
+            iceServers: [
+              {"urls": ["turn:YOUR.TURN.SERVER:3478"], "username": "YOUR.USER", "credential": "YOUR.PASSWORD"},
+              {"urls": ["stun:YOUR.STUN.SERVER:3478"], "username": "", "credential": ""}]
+          }
+        }
+      }
+    }
+  }
+})
+```
+
 ## Configuration examples
 
 As libp2p is designed to be a modular networking library, its usage will vary based on individual project needs. We've included links to some existing project configurations for your reference, in case you wish to replicate their configuration:

src/transport-manager.js

@@ -20,6 +20,7 @@ class TransportManager {
     this.upgrader = upgrader
     this._transports = new Map()
     this._listeners = new Map()
+    this._listenerOptions = new Map()
     this.faultTolerance = faultTolerance
   }
 
@@ -47,6 +48,7 @@ class TransportManager {
     })
 
     this._transports.set(key, transport)
+    this._listenerOptions.set(key, transportOptions.listenerOptions || {})
     if (!this._listeners.has(key)) {
       this._listeners.set(key, [])
     }
@@ -154,7 +156,7 @@ class TransportManager {
       // For each supported multiaddr, create a listener
       for (const addr of supportedAddrs) {
         log('creating listener for %s on %s', key, addr)
-        const listener = transport.createListener({}, this.onConnection)
+        const listener = transport.createListener(this._listenerOptions.get(key), this.onConnection)
         this._listeners.get(key).push(listener)
 
         // We need to attempt to listen on everything

test/transports/transport-manager.node.js

@@ -10,6 +10,7 @@ const TransportManager = require('../../src/transport-manager')
 const Transport = require('libp2p-tcp')
 const multiaddr = require('multiaddr')
 const mockUpgrader = require('../utils/mockUpgrader')
+const sinon = require('sinon')
 const addrs = [
   multiaddr('/ip4/127.0.0.1/tcp/0'),
   multiaddr('/ip4/127.0.0.1/tcp/0')
@@ -40,7 +41,9 @@ describe('Transport Manager (TCP)', () => {
   })
 
   it('should be able to listen', async () => {
-    tm.add(Transport.prototype[Symbol.toStringTag], Transport)
+    tm.add(Transport.prototype[Symbol.toStringTag], Transport, { listenerOptions: { listen: 'carefully' } })
+    const transport = tm._transports.get(Transport.prototype[Symbol.toStringTag])
+    const spyListener = sinon.spy(transport, 'createListener')
     await tm.listen()
     expect(tm._listeners).to.have.key(Transport.prototype[Symbol.toStringTag])
     expect(tm._listeners.get(Transport.prototype[Symbol.toStringTag])).to.have.length(addrs.length)
@@ -48,6 +51,7 @@ describe('Transport Manager (TCP)', () => {
     expect(tm.getAddrs().length).to.equal(addrs.length)
     await tm.close()
     expect(tm._listeners.get(Transport.prototype[Symbol.toStringTag])).to.have.length(0)
+    expect(spyListener.firstCall.firstArg).to.deep.equal({ listen: 'carefully' })
   })
 
   it('should be able to dial', async () => {

test/transports/transport-manager.spec.js

@@ -125,7 +125,10 @@ describe('libp2p.transportManager', () => {
     const spy = sinon.spy()
     const key = spy.prototype[Symbol.toStringTag] = 'TransportSpy'
     const customOptions = {
-      another: 'value'
+      another: 'value',
+      listenerOptions: {
+        listen: 'carefully'
+      }
     }
     libp2p = new Libp2p({
       peerId,
@@ -143,6 +146,7 @@ describe('libp2p.transportManager', () => {
     expect(libp2p.transportManager).to.exist()
     // Our transport and circuit relay
     expect(libp2p.transportManager._transports.size).to.equal(2)
+    expect(libp2p.transportManager._listenerOptions.size).to.equal(2)
     expect(spy).to.have.property('callCount', 1)
     expect(spy.getCall(0)).to.have.deep.property('args', [{
       ...customOptions,