Allow server host to decide peer to peer behavior

.gitignore

@@ -1,2 +1,4 @@
 dist/
-node_modules/
+node_modules/
+config/*
+!config/*.example.*

README.md

@@ -28,6 +28,8 @@
 * [Getting Started](#getting-started)
   * [Prerequisites](#prerequisites)
   * [Installation](#installation)
+  * [Fixing Connection Issues](#fixing-connection-issue)
+  * [Protecting Player IP Addresses](#protecting-player-ip-addresses)
 * [Contributing](#contributing)
 * [License](#license)
 
@@ -44,7 +46,7 @@ To get up and running quickly, you can deploy to Heroku using the button below
 
 [![Deploy](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy)
 
-This will deploy an instance of the crewlink-server. You can get the URL of your server by using the app name that you gave when you launched the app on heroku and appending `.herokuapp.com`. You can also find the URL of your server by going to "Settings", scrolling down to "Domains", and removing the `https://` and trailing slash from the url. Using this URL, follow step 4 of the [installation instructions](https://github.com/ottomated/CrewLink-server#manual-installation) to connect your client to your server instance.
+This will deploy an instance of the crewlink-server. You can get the URL of your server by using the app name that you gave when you launched the app on heroku and appending `.herokuapp.com`. You can also find the URL of your server by going to "Settings", scrolling down to "Domains". Using this URL, follow step 4 of the [installation instructions](https://github.com/ottomated/CrewLink-server#manual-installation) to connect your client to your server instance.
 
 ## Docker Quickstart
 
@@ -101,7 +103,22 @@ yarn install
 ```JS
 yarn start
 ```
-4. Copy your server's IP and port into CrewLink settings. Make sure everyone in your lobby is using the same server.
+4. Copy your server URL into CrewLink settings. Make sure everyone in your lobby is using the same server.
+
+### Fixing Connection Issues
+
+CrewLink-server should work out of the box for most people. You may, however, come across people who are unable to hear 
+other people, no matter what they try. This could be because of a NAT or firewall that is preventing peer to peer
+connections. In this case you may want to set up your own relay server to act as a middleman for your voice traffic.
+CrewLink needs a specific type of server for this called a TURN server. As of yet CrewLink does not come with one by
+default. 
+
+You can configure a turn server by creating a file called ``peer-config.yml`` in the config folder. Use the
+Provided example as a template. A good, open source TURN server implementation is [Coturn](https://github.com/coturn/coturn).
+
+### Protecting Player IP Addresses
+A relay server may also be desirable in case you want to prevent CrewLink players from detecting the IP addresses of
+everyone in the same Among Us room using CrewLink. Check the section above on how to set one up.
 
 <!-- CONTRIBUTING -->
 ## Contributing

config/peer-config.example.yml

@@ -0,0 +1,32 @@
+# IN ORDER TO USE THIS CONFIG FILE, RENAME IT AND REMOVE THE ".example" PART OF THE FILENAME!
+#
+# CrewLink peer to peer connection configuration.
+#
+# This file lets you modify how CrewLink connects players to each other.
+#
+# CrewLink uses peer to peer connections to establish voice calls between players. This means that every player has to
+# be able to connect to every other player some way or another in order for CrewLink to work. Below you can tweak the
+# mechanisms CrewLink uses to establish peer to peer connections.
+
+# Force CrewLink to only work through TURN servers. This is great if you want to protect the IP addresses of players
+# as no direct connection will be made. If set to true, a TURN server is required.
+forceRelayOnly: false
+
+# STUN servers
+# A part of establishing peer to peer connections is finding out the IP address of each participant and letting people 
+# connect directly to each other. A stun server, simply put, allows you to find out your public IP address and port, 
+# which is something other participants need to know in order to connect to you. By default CrewLink will use one of
+# Google's STUN servers.
+stunServers:
+  - url: 'stun:stun.l.google.com:19302'
+
+# TURN servers:
+#     Sometimes you find yourself behind a strict firewall or NAT that flat out rejects peer to peer connections. TURN
+#     servers provide a way around this by acting as a middleman between peers, relaying all traffic sent between them.
+#     TURN servers are the best way to guarantee that everyone can use CrewLink. By default CrewLink comes with no TURN
+#     servers, so you will need to set one up. Beware that TURN servers take up a lot of bandwidth as they have to relay
+#     ALL traffic between peers that use them.
+# turnServers:
+#   - url: 'turn:example.com'
+#     username: 'TurnUsername'
+#     credential: 'TurnPassword'

package.json

@@ -9,7 +9,8 @@
   "public-ip": "^4.0.2",
   "pug": "^3.0.0",
   "socket.io": "^2.3.0",
-  "tracer": "^1.1.4"
+  "tracer": "^1.1.4",
+  "yaml": "^1.10.0"
  },
  "scripts": {
   "start": "yarn compile && node dist/index.js",

src/index.ts

@@ -4,6 +4,7 @@ import socketIO from 'socket.io';
 import Tracer from 'tracer';
 import morgan from 'morgan';
 import publicIp from 'public-ip';
+import peerConfig from './peer-config';
 
 const port = parseInt(process.env.PORT || '9736');
 
@@ -22,22 +23,27 @@ interface Signal {
 	to: string;
 }
 
-app.set('view engine', 'pug')
-app.use(morgan('combined'))
-app.use(express.static('offsets'))
+interface SetIDsPacket {
+	[key: string]: number
+}
+
+app.set('view engine', 'pug');
+app.use(morgan('combined'));
+app.use(express.static('offsets'));
 let connectionCount = 0;
 let address = 'loading...';
 
 app.get('/', (req, res) => {
 	res.render('index', { connectionCount, address });
-})
-
+});
 
 io.on('connection', (socket: socketIO.Socket) => {
 	connectionCount++;
 	logger.info("Total connected: %d", connectionCount);
 	let code: string | null = null;
 
+	socket.emit('peerConfig', peerConfig);
+
 	socket.on('join', (c: string, id: number) => {
 		if (typeof c !== 'string' || typeof id !== 'number') {
 			socket.disconnect();
@@ -48,9 +54,9 @@ io.on('connection', (socket: socketIO.Socket) => {
 		socket.join(code);
 		socket.to(code).broadcast.emit('join', socket.id, id);
 
-		let socketsInLobby = Object.keys(io.sockets.adapter.rooms[code].sockets);
-		let ids: any = {};
-		for (let s of socketsInLobby) {
+		const socketsInLobby = Object.keys(io.sockets.adapter.rooms[code].sockets);
+		const ids: SetIDsPacket = {};
+		for (const s of socketsInLobby) {
 			if (s !== socket.id)
 				ids[s] = playerIds.get(s);
 		}
@@ -65,12 +71,12 @@ io.on('connection', (socket: socketIO.Socket) => {
 		}
 		playerIds.set(socket.id, id);
 		socket.to(code).broadcast.emit('setId', socket.id, id);
-	})
+	});
 
 
 	socket.on('leave', () => {
 		if (code) socket.leave(code);
-	})
+	});
 
 	socket.on('signal', (signal: Signal) => {
 		if (typeof signal !== 'object' || !signal.data || !signal.to || typeof signal.to !== 'string') {
@@ -88,9 +94,8 @@ io.on('connection', (socket: socketIO.Socket) => {
 	socket.on('disconnect', () => {
 		connectionCount--;
 		logger.info("Total connected: %d", connectionCount);
-	})
-
-})
+	});
+});
 
 server.listen(port);
 (async () => {

src/peer-config.ts

@@ -0,0 +1,24 @@
+import YAML from 'yaml';
+import path from 'path';
+import fs from 'fs';
+
+const PEER_CONFIG_PATH = path.join(__dirname, '..', 'config', 'peer-config.yml');
+const DEFAULT_PEER_CONFIG = {
+	forceRelayOnly: false,
+	stunServers: [
+		{
+			url: 'stun:stun.l.google.com:19302'
+		}
+	]
+};
+
+let peerConfig = DEFAULT_PEER_CONFIG;
+if (fs.existsSync(PEER_CONFIG_PATH)) {
+	try {
+		peerConfig = YAML.parse(fs.readFileSync(PEER_CONFIG_PATH).toString('utf8'));
+	} catch (err) {
+		console.error(`Unable to load ICE server config file. Make sure it is valid YAML.\n${err}`);
+	}
+}
+
+export default peerConfig;

yarn.lock

@@ -1267,6 +1267,11 @@ xmlhttprequest-ssl@~1.5.4:
   resolved "https://registry.yarnpkg.com/xmlhttprequest-ssl/-/xmlhttprequest-ssl-1.5.5.tgz#c2876b06168aadc40e57d97e81191ac8f4398b3e"
   integrity sha1-wodrBhaKrcQOV9l+gRkayPQ5iz4=
 
+yaml@^1.10.0:
+  version "1.10.0"
+  resolved "https://registry.yarnpkg.com/yaml/-/yaml-1.10.0.tgz#3b593add944876077d4d683fee01081bd9fff31e"
+  integrity sha512-yr2icI4glYaNG+KWONODapy2/jDdMSDnrONSjblABjD9B4Z5LgiircSt8m8sRZFNi08kG9Sm0uSHtEmP3zaEGg==
+
 [email protected]:
   version "0.1.2"
   resolved "https://registry.yarnpkg.com/yeast/-/yeast-0.1.2.tgz#008e06d8094320c372dbc2f8ed76a0ca6c8ac419"