MaBecker/CaptivePortal.js

## CaptivePortal.js
// Captive Portal

var http = require('http');
var Wifi = require('Wifi');

var dgram = require('dgram');

var server = dgram.createSocket('udp4');

var SSID  = 'CaptivePortalTest';
var authMode = 'open';
var password = null;
var portHTTP = 80;
var portDNS  = 53;

var dnsIPStr = '192.168.4.1';
var dnsIP    = dnsIPStr.split('.').map(n => String.fromCharCode(parseInt(n, 10))).join('');

var page = '<html><body><H1>Hello World</H1></body></html>';


// get Query name out of message
// offset = 12
// end \x00
function dnsQname(msg) {
  var i = 12;
  var qname = '';
  while ( msg[i] !== '\x00' ) {
    qname +=  msg[i];
    i++;
  }
  return qname + '\x00';
}

/*
1. line header
2. line query
3. line resource
*/
function dnsResponse(msg,dns_ip){
  return msg[0]+msg[1] + '\x81\x80'+'\x00\x01'+'\x00\x01'+'\x00\x00\x00\x00' +
         dnsQname(msg) + '\x00\x01' + '\x00\x01' +
         '\xc0\x0c'+'\x00\x01'+'\x00\x01'+'\x00\x00\x00\xf9'+'\x00\x04' + dns_ip  ;
}

function startDNSServer(port){
  server.on('error', (err) => {
    server.close();
  });
  server.on('message', (msg, info) => {
    // we only serve ip4
    if ( msg[msg.length-3] === '\x01') {
      server.send(dnsResponse(msg,dnsIP),info.port,info.address);
    }
  });
  server.bind(port);
}

// start http server
function startHttpServer(port){
  var server = http.createServer(function (req, res) {
    accept = req.headers.Accept || '';
    if (accept !== '*\/*') {
      res.writeHead(200, {'Content-Type': 'text/html'});
      res.end(page);
    } else { // redirect to the Setup page
      res.writeHead(302, {'Location': 'http://192.168.4.1',
                          'Content-Type': 'text/plain'});
      res.end();
    }
  });
  server.listen(port);
}

// start beeing a access point
function startAccessPoint(ssid,authMode, password){
  Wifi.startAP(ssid,{"authMode" : authMode,"password" : password});
}

// stop beeing connected to a access point
function disconnectStation(){
  Wifi.disconnect();
}

function start(){
  disconnectStation();
  startAccessPoint('CaptivePortalTest','open',null);
  startHttpServer(80);
  startDNSServer(53);
}

setTimeout(start,1000);
	// Captive Portal

	var http = require('http');
	var Wifi = require('Wifi');

	var dgram = require('dgram');

	var server = dgram.createSocket('udp4');

	var SSID = 'CaptivePortalTest';
	var authMode = 'open';
	var password = null;
	var portHTTP = 80;
	var portDNS = 53;

	var dnsIPStr = '192.168.4.1';
	var dnsIP = dnsIPStr.split('.').map(n => String.fromCharCode(parseInt(n, 10))).join('');

	var page = '<html><body><H1>Hello World</H1></body></html>';



	// get Query name out of message
	// offset = 12
	// end \x00
	function dnsQname(msg) {
	var i = 12;
	var qname = '';
	while ( msg[i] !== '\x00' ) {
	qname += msg[i];
	i++;
	}
	return qname + '\x00';
	}

	/*
	1. line header
	2. line query
	3. line resource
	*/
	function dnsResponse(msg,dns_ip){
	return msg[0]+msg[1] + '\x81\x80'+'\x00\x01'+'\x00\x01'+'\x00\x00\x00\x00' +
	dnsQname(msg) + '\x00\x01' + '\x00\x01' +
	'\xc0\x0c'+'\x00\x01'+'\x00\x01'+'\x00\x00\x00\xf9'+'\x00\x04' + dns_ip ;
	}

	function startDNSServer(port){
	server.on('error', (err) => {
	server.close();
	});
	server.on('message', (msg, info) => {
	// we only serve ip4
	if ( msg[msg.length-3] === '\x01') {
	server.send(dnsResponse(msg,dnsIP),info.port,info.address);
	}
	});
	server.bind(port);
	}

	// start http server
	function startHttpServer(port){
	var server = http.createServer(function (req, res) {
	accept = req.headers.Accept \|\| '';
	if (accept !== '\/') {
	res.writeHead(200, {'Content-Type': 'text/html'});
	res.end(page);
	} else { // redirect to the Setup page
	res.writeHead(302, {'Location': 'http://192.168.4.1',
	'Content-Type': 'text/plain'});
	res.end();
	}
	});
	server.listen(port);
	}

	// start beeing a access point
	function startAccessPoint(ssid,authMode, password){
	Wifi.startAP(ssid,{"authMode" : authMode,"password" : password});
	}

	// stop beeing connected to a access point
	function disconnectStation(){
	Wifi.disconnect();
	}

	function start(){
	disconnectStation();
	startAccessPoint('CaptivePortalTest','open',null);
	startHttpServer(80);
	startDNSServer(53);
	}

	setTimeout(start,1000);