Node JS TCP Proxy: Set up HTTP Tunnel using Node JS

Question

I'm trying to implement a TCP proxy in Node JS. I only have some experience with Javascript so I met a lot of problems along the way. I've done a lot of searching for this one but had no luck.

I want to implement a two-hop TCP connection for HTTPS proxy. Here is part of my code.

var net = require('net');

var server = net.createServer(function(clientSock) {

    var connected = false;    

    var serverSock;

    clientSock.on('data', function(clientData) {

        if (connected) {

            // Send future messages if is connected
            serverSocet.write(clientData);

        } else {

            var host = // get from data
            var port = // get from data

            if (clientData is a CONNECT request) {

                // Create a new socket to server
                if (!serverSock) {
                    serverSock = new net.Socket();

                    serverSock.connect(port, host, function() {

                        // Send the CONNECT request (Client Hello)
                        serverSock.write(clientData);

                        connected = true;

                        clientSock.write('HTTP/1.1 200 OK\r\n');
                   });

                   serverSock.on('data', function(serverData) {
                        clientSock.write(serverData);
                   });
               }
          }
     });
 });

I used Wireshark to capture the packets sent if I visit https://www.google.com. If I don't use my proxy, the "Client Hello" message is sent in TLS v1.2. But if I use my proxy, it is sent by SSL. The server always reject my CONNECT request and send back a reset request.

I also tried the TLS API in Node JS. The server accepted my CONNECT request but always request me to start a new session after the Key Exchange. The browser will close the socket and create a new socket. But it never loaded the page...

I've spent a whole day on this single problem. I believe I can use TCP socket to implement HTTP Tunnel. Please help... Thanks a lot!!

score 2 · Accepted Answer · answered May 14 '15 at 18:38

Problem solved!

To make TCP socket use TLS v1.2 while dealing with HTTPS, just put this option, {allowHalfOpen: true}, as parameter when creating the sockets.

New Code would look like this:

var net = require('net');

                               // option here
var server = net.createServer({allowHalfOpen: true}, function(clientSock) {

var connected = false;    

var serverSock;

clientSock.on('data', function(clientData) {

    if (connected) {

        // Send future messages if is connected
        serverSocet.write(clientData);

    } else {

        var host = // get from data
        var port = // get from data

        if (clientData is a CONNECT request) {

            // Create a new socket to server
            if (!serverSock) {

                                             // Option here
                serverSock = new net.Socket({allowHalfOpen: true});

                serverSock.connect(port, host, function() {

                    // Don't need to forward hello message from client
                    // Connect method automatically sends it for you
                    //serverSock.write(clientData);

                    connected = true;

                    clientSock.write('HTTP/1.1 200 OK\r\n');
               });

               serverSock.on('data', function(serverData) {
                    clientSock.write(serverData);
               });
           }
      }
 });

Node JS TCP Proxy: Set up HTTP Tunnel using Node JS

1 Answers1