reorg code, integration publish/subscribe working, still some TODOs

broker/broker.js

@@ -0,0 +1,102 @@
+const Websocket = require('ws');
+//const Mqtt = require('mqtt');
+//const Aedes = require('aedes')(); /* aedes is a stream-based MQTT broker */
+//const MQTTserver = require('net').createServer(aedes.handle);
+
+const ChainUtil = require('../chain-util');
+const crypto = require('crypto');
+
+const STATE_CLIENT_HELLOING = 0;
+const STATE_OPERATIONAL = 1;
+
+function onClientHelloing(parent, socket, data) {
+  const asJson = JSON.parse(data);
+  const owner = asJson.owner;
+  const sensor = asJson.sensor;
+  const signature = asJson.signature;
+  const clientNonce = asJson.clientNonce;
+
+  if (typeof owner !== 'string' || typeof sensor !== 'string' || typeof signature !== 'object' || typeof clientNonce !== 'string') {
+    console.log("Bad client hello");
+    socket.close();
+    return;
+  }
+  socket.owner = owner;
+  socket.sensor = sensor;
+  socket.clientNonce = clientNonce;
+  const verifyRes = ChainUtil.verifySignature(owner, signature, socket.serverNonce + clientNonce);
+  if (!verifyRes.result) {
+    console.log("Bad client hello signature: " + verifyRes.reason);
+    socket.close();
+    return;
+  }
+
+  const ourSig = parent.keyPair.sign(clientNonce + socket.serverNonce);
+  socket.send(JSON.stringify(ourSig));
+  socket.state = STATE_OPERATIONAL;
+  console.log(`Sensor ${socket.owner}:${socket.sensor} is operational`);
+}
+
+function onOperational(parent, socket, data) {
+  parent.onMessage(socket.sensor, data);
+}
+
+function onSocketMessage(parent, socket, data) {
+  switch (socket.state) {
+    case STATE_CLIENT_HELLOING: onClientHelloing(parent, socket, data); break;
+    case STATE_OPERATIONAL: onOperational(parent, socket, data); break;
+    default: throw Error("Invalid internal state");
+  }
+}
+
+class Socket {
+  constructor(parent, socket, serverNonce) {
+    this.parent = parent;
+    this.socket = socket;
+    this.serverNonce = serverNonce;
+    this.state = STATE_CLIENT_HELLOING;
+    this.socket.on('message', (data) => {
+      onSocketMessage(parent, this, data);
+    });
+    this.send(serverNonce);
+  }
+
+  send(data) {
+    this.socket.send(data);
+  }
+
+  close() {
+    this.socket.close();
+  }
+}
+
+function onConnection(broker, rawSocket) {
+  console.log("Sensor connected");
+  crypto.randomBytes(2048, (err, buf) => {
+    if (err) {
+      console.log(`Couldn't generate server nonce: ${err}`);
+      rawSocket.close();
+      return;
+    }
+    new Socket(broker, rawSocket, buf.toString('hex'));
+  });
+}
+
+class Broker {
+  constructor(keyPair) {
+    //owner:sensor->mqtt channel
+    this.brokering = {};
+    this.keyPair = keyPair;
+  }
+
+  start(sensorPort, onMessage) {
+    this.onMessage = onMessage;
+    this.sensorPort = sensorPort;
+    this.server = new Websocket.Server({ port: this.sensorPort });
+    this.server.on('connection', socket => onConnection(this, socket));
+
+    console.log(`Broker listening for sensors on: ${this.sensorPort}`);
+  }
+}
+
+module.exports = Broker;