91 lines
2.0 KiB
JavaScript
91 lines
2.0 KiB
JavaScript
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'use strict';
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var electron = require('electron');
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var dns = require('dns-suite');
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var ipc = electron.ipcMain;
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var win;
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var socket;
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var mdnsPort = 5353;
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var broadcastAddr = '224.0.0.251';
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var queryname = '_cloud._tcp.local';
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function sendDeviceQuery() {
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var id = require('crypto').randomBytes(2).readUInt16LE();
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var rpacket = {
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header: {
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id: id,
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qr: 0,
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opcode: 0,
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aa: 0,
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tc: 0,
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rd: 0,
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ra: 0,
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res1: 0,
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res2: 0,
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res3: 0,
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rcode: 0,
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},
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question: [
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{
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name: queryname,
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typeName: 'PTR',
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className: 'IN',
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},
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],
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};
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var buf = dns.DNSPacket.write(rpacket);
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socket.send(buf, mdnsPort, broadcastAddr, function () {
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console.log('sent mDNS query', buf.toString('hex'));
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});
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}
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function handleAnswer(message/*, rinfo*/) {
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// console.log('received %d bytes from %s:%d', message.length, rinfo.address, rinfo.port);
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var packet;
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try {
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packet = dns.DNSPacket.parse(message);
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} catch (error) {
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// The majority of the packets collected just listening to our local network seem to
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// throw exceptions, so don't bother logging them.
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return;
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}
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// We are only interested in responses
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if (packet.header.qr !== 1) {
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return;
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}
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// And we only want the responses to the question we send (should be sent back in response)
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if (packet.question.length !== 1 || packet.question[0].name !== queryname) {
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return;
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}
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win.webContents.send('deviceFound', packet);
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}
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function init(window) {
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if (win) {
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console.error("can't initialize device discovery multiple times");
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return;
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}
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win = window;
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socket = require('dgram').createSocket({ type: 'udp4', reuseAddr: true });
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socket.on('message', handleAnswer);
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socket.bind(mdnsPort, function () {
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var addr = this.address();
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console.log('mDNS device discovery bound on %s:%d', addr.address, addr.port);
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socket.setBroadcast(true);
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socket.addMembership(broadcastAddr);
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});
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ipc.on('startDeviceScan', sendDeviceQuery);
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}
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module.exports = {
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init: init,
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};
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