goldilocks.js/lib/goldilocks.js

'use strict';

module.exports.create = function (deps, config) {
  console.log('config', config);

  //var PromiseA = global.Promise;
  var PromiseA = require('bluebird');
  var listeners = require('./servers').listeners;
  var modules;

  function loadModules() {
    modules = {};

    modules.tls = require('./modules/tls').create(deps, config, netHandler);
    modules.http = require('./modules/http.js').create(deps, config, modules.tls.middleware);
  }

  // opts = { servername, encrypted, peek, data, remoteAddress, remotePort }
  function peek(conn, firstChunk, opts) {
    if (!modules) {
      loadModules();
    }

    opts.firstChunk = firstChunk;
    conn.__opts = opts;
    // TODO port/service-based routing can do here

    // TLS byte 1 is handshake and byte 6 is client hello
    if (0x16 === firstChunk[0]/* && 0x01 === firstChunk[5]*/) {
      modules.tls.emit('connection', conn);
      return;
    }

    // This doesn't work with TLS, but now that we know this isn't a TLS connection we can
    // unshift the first chunk back onto the connection for future use. The unshift should
    // happen after any listeners are attached to it but before any new data comes in.
    if (!opts.hyperPeek) {
      process.nextTick(function () {
        conn.unshift(firstChunk);
      });
    }

    // Connection is not TLS, check for HTTP next.
    if (firstChunk[0] > 32 && firstChunk[0] < 127) {
      var firstStr = firstChunk.toString();
      if (/HTTP\//i.test(firstStr)) {
        modules.http.emit('connection', conn);
        return;
      }
    }

    console.warn('failed to identify protocol from first chunk', firstChunk);
    conn.close();
  }
  function netHandler(conn, opts) {
    opts = opts || {};
    console.log('[netHandler]', conn.localAddress, conn.localPort, opts.encrypted);

    // XXX PEEK COMMENT XXX
    // TODO we can have our cake and eat it too
    // we can skip the need to wrap the TLS connection twice
    // because we've already peeked at the data,
    // but this needs to be handled better before we enable that
    // (because it creates new edge cases)
    if (opts.hyperPeek) {
      console.log('hyperpeek');
      peek(conn, opts.firstChunk, opts);
      return;
    }

    conn.once('data', function (chunk) {
      peek(conn, chunk, opts);
    });
  }

  function dnsListener(msg) {
    var dgram = require('dgram');
    var socket = dgram.createSocket('udp4');
    socket.send(msg, config.dns.proxy.port, config.dns.proxy.address || '127.0.0.1');
  }

  function createTcpForwarder(mod) {
    var destination = mod.address.split(':');
    var connected = false;

    return function (conn) {
      var newConn = deps.net.createConnection({
        port: destination[1]
      , host: destination[0] || '127.0.0.1'

      , remoteFamily:  conn.remoteFamily
      , remoteAddress: conn.remoteAddress
      , remotePort:    conn.remotePort
      }, function () {
        connected = true;

        newConn.pipe(conn);
        conn.pipe(newConn);
      });

      // Not sure how to effectively report this to the user or client, but we need to listen
      // for the event to prevent it from crashing us.
      newConn.on('error', function (err) {
        if (connected) {
          console.error('TCP forward remote error', err);
          conn.end();
        } else {
          console.log('TCP forward connection error', err);
          require('./proxy-err-resp').sendBadGateway(conn, err, config.debug);
        }
      });
      conn.on('error', function (err) {
        console.error('TCP forward client error', err);
        newConn.end();
      });

    };
  }

  deps.tunnel = deps.tunnel || {};
  deps.tunnel.net = {
    createConnection: function (opts, cb) {
      console.log('[gl.tunnel] creating connection');

      // here "reader" means the socket that looks like the connection being accepted
      // here "writer" means the remote-looking part of the socket that driving the connection
      var writer;
      var wrapOpts = {};
      var rawTls = opts.tls || (0x16 === opts.data[0]) && (0x01 === opts.data[5]);

      function usePair(err, reader) {
        if (err) {
          process.nextTick(function () {
            writer.emit('error', err);
          });
          return;
        }

        // this has the normal net/tcp stuff plus our custom stuff
        // opts = { address, port,
        //          hostname, servername, tls, encrypted, data, localAddress, localPort, remoteAddress, remotePort, remoteFamily }
        Object.keys(opts).forEach(function (key) {
          wrapOpts[key] = opts[key];
          try {
            reader[key] = opts[key];
          } catch(e) {
            // can't set real socket getters, like remoteAddr
          }
        });

        // A few more extra specialty options
        wrapOpts.localAddress = wrapOpts.localAddress || '127.0.0.2'; // TODO use the tunnel's external address
        wrapOpts.localPort = wrapOpts.localPort || 'tunnel-0';
        try {
          reader._remoteAddress = wrapOpts.remoteAddress;
          reader._remotePort = wrapOpts.remotePort;
          reader._remoteFamily = wrapOpts.remoteFamily;
          reader._localAddress = wrapOpts.localAddress;
          reader._localPort = wrapOpts.localPort;
          reader._localFamily = wrapOpts.localFamily;
        } catch(e) {
        }

        netHandler(reader, wrapOpts);

        process.nextTick(function () {
          //opts.data = wrapOpts.data;

          // this cb will cause the stream to emit its (actually) first data event
          // (even though it already gave a peek into that first data chunk)
          console.log('[tunnel] callback, data should begin to flow');
          cb();
        });
      }

      wrapOpts.firstChunk = opts.data;
      wrapOpts.hyperPeek = !!opts.data;
      // encrypted meaning is *terminated* TLS
      // tls meaning is *raw* TLS
      if (rawTls) {
        // TLS sockets must actually use a socket with a file descriptor
        // https://nodejs.org/api/net.html#net_class_net_socket

        writer = require('socket-pair').create(function (err, other) {
          usePair(err, other);
        });
      }
      else {
        // stream-pair can only be used by TCP sockets, not tls
        writer = require('stream-pair').create();
        usePair(null, writer.other);
      }

      return writer;
    }
  };

  var listenPromises = [];
  var tcpPortMap = {};
  function addPorts(bindList) {
    if (!bindList) {
      return;
    }
    if (Array.isArray(bindList)) {
      bindList.forEach(function (port) {
        tcpPortMap[port] = true;
      });
    }
    else {
      tcpPortMap[bindList] = true;
    }
  }

  addPorts(config.tcp.bind);
  (config.tcp.modules || []).forEach(function (mod) {
    if (mod.name === 'forward') {
      var forwarder = createTcpForwarder(mod);
      mod.ports.forEach(function (port) {
        if (!tcpPortMap[port]) {
          console.log("forwarding port", port, "that wasn't specified in bind");
        } else {
          delete tcpPortMap[port];
        }
        listenPromises.push(listeners.tcp.add(port, forwarder));
      });
    }
    else {
      console.warn('unknown TCP module specified', mod);
    }
  });

  // Even though these ports were specified in different places we treat any TCP
  // connections we haven't been told to just forward exactly as is equal so that
  // we can potentially use the same ports for different protocols.
  addPorts(config.tls.bind);
  addPorts(config.http.bind);

  Object.keys(tcpPortMap).forEach(function (port) {
    listenPromises.push(listeners.tcp.add(port, netHandler));
  });

  if (config.dns.bind) {
    if (Array.isArray(config.dns.bind)) {
      config.dns.bind.map(function (port) {
        listenPromises.push(listeners.udp.add(port, dnsListener));
      });
    } else {
      listenPromises.push(listeners.udp.add(config.dns.bind, dnsListener));
    }
  }

  return PromiseA.all(listenPromises);
};