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

sensor/sensor.js

@@ -0,0 +1,108 @@
+const Websocket = require('ws');
+
+const ChainUtil = require('../chain-util');
+const crypto = require('crypto');
+
+const STATE_SERVER_HELLOING = 0;
+const STATE_SERVER_FINNING = 1;
+const STATE_OPERATIONAL = 2;
+
+function onServerHelloing(sensor, data) {
+  const serverNonce = data.toString();
+
+  if (typeof serverNonce !== 'string') {
+    console.log("Bad server hello");
+    sensor.close();
+    return;
+  }
+  sensor.serverNonce = serverNonce;
+
+  crypto.randomBytes(2048, (err, buf) => {
+    if (err) {
+      console.log(`Couldn't generate client nonce: ${err}`);
+      sensor.close();
+      return;
+    }
+
+    sensor.clientNonce = buf.toString('hex');
+
+    sensor.socket.send(JSON.stringify({
+      owner: sensor.keyPair.getPublic().encode('hex'),
+      sensor: sensor.sensorId,
+      signature: sensor.keyPair.sign(sensor.serverNonce + sensor.clientNonce),
+      clientNonce: sensor.clientNonce
+    }));
+    sensor.state = STATE_SERVER_FINNING;
+  });
+}
+
+function onServerFinning(sensor, data) {
+  const signature = JSON.parse(data);
+  if (typeof signature !== 'object') {
+    console.log("Bad server fin");
+    sensor.close();
+    return;
+  }
+
+  if (sensor.brokerPublicKey !== null) {
+    const verifyRes = ChainUtil.verifySignature(sensor.brokerPublicKey, data, sensor.clientNonce + sensor.serverNonce);
+    if (!verifyRes.result) {
+      console.log("Bad server fin singature: " + verifyRes.reason);
+      sensor.close();
+      return;
+    }
+    console.log("Broker authed, operational");
+  } else {
+    console.log("No broker public key stored, blindly trusting the broker");
+  }
+
+  sensor.state = STATE_OPERATIONAL;
+  for (const msg of sensor.queue) {
+    sensor.send(msg);
+  }
+}
+
+function onOperational(_, _) {
+}
+
+function onSocketMessage(sensor, data) {
+  switch (sensor.state) {
+    case STATE_SERVER_HELLOING: onServerHelloing(sensor, data); break;
+    case STATE_SERVER_FINNING: onServerFinning(sensor, data); break;
+    case STATE_OPERATIONAL: onOperational(sensor, data); break;
+    default: throw Error("Invalid internal state");
+  }
+}
+
+function onConnection(sensor) {
+  sensor.socket.on('message', (data) => {
+    onSocketMessage(sensor, data);
+  });
+}
+
+class Sensor {
+  constructor(keyPair, sensorId, brokerLocation, brokerPublicKey) {
+    this.keyPair = keyPair;
+    this.sensorId = sensorId;
+    this.brokerPublicKey = brokerPublicKey;
+    this.state = STATE_SERVER_HELLOING;
+    this.queue = [];
+
+    this.socket = new Websocket(brokerLocation);
+    this.socket.on('open', (_) => onConnection(this));
+  }
+
+  send(data) {
+    if (this.state != STATE_OPERATIONAL) {
+      this.queue.push(data);
+    } else {
+      this.socket.send(data);
+    }
+  }
+
+  close() {
+    this.socket.close();
+  }
+}
+
+module.exports = Sensor;