node-port-mux

Multiplex multiple services through one (TCP) port.

How?

The muxer basically sniffs the initial data packet sent by the client to determine (using a rule set) where to forward the request to.

Why?

Instead of having to expose all your services to the outside world on their respective ports, use a single port to access them all. Initially created to multiplex HTTP, HTTPS and SOCKS5 traffic over one port for a personal project.

Install

From the NPM repository:

$ npm install port-mux

From the Github repository:

$ git clone https://github.com/robertklep/node-port-mux.git
$ cd node-port-mux
$ npm install [-g]

Example

var Muxer = require('port-mux');

// instantiate Muxer
Muxer()
  // match HTTP GET requests (using a prefix string match) and forward them to localhost:80
  .addRule('GET ', 80)

  // match TLS (HTTPS) requests (versions 3.{0,1,2,3}) using a regular expression
  .addRule(/^\x16\x03[\x00-\x03]/, '192.168.1.1:443') // regex match

  // you can forward to UNIX domain sockets (which should already exist when you call .addRule()):
  .addRule(..., '/tmp/my-unix-domain-socket')

  // you can also provide a function to perform the matching:
  .addRule(function(chunk) {
    // - chunk is a Buffer containing the first incoming data
    // - if the function returns true, the match is considered a success.
  }, ...)

  // pass a function as a third argument and it will get called (once the proxy
  // has connected to the service) using the proxy connection and original
  // (incoming) connection as arguments:
  .addRule(..., ..., function(proxy, conn) {
    var addr = proxy.address();
    console.log('Incoming connection from %s passed to %s:%s',
      conn.remoteAddress,
      addr.address,
      addr.port
    );
  })

  // start listening on port 3000
  .listen(3000);

Performance impact

There's going to be a performance impact when using this module, since it's proxying connections to the endpoint.

Using httperf, these are the results I get on a Macbook Pro (using the modified version of the example.js script in the repository):

Type of connection	Reqs/s	I/O speed	Remarks
Direct	9991	1863 KB/s	access HTTP server directly (not muxed)
Muxed (TCP)	4881	910 KB/s	HTTP server uses TCP sockets
Muxed (UNIX)	5629	1050 KB/s	HTTP server uses UNIX domain sockets

So performance impact is about 50%, a bit less when you use UNIX domain sockets.

LICENSE

Simplified BSD License ( BSD-2-Clause ).