tcpip.js

TCP/IP stack for JS (built on gVisor + WASM)

Features

• Browser/Server: A user-space TCP/IP stack for the browser or server
• Polyfill: Node.js compatible net API allowing you to use server-side libraries in the browser
• Trusted: Built on top of gVisor's tcpip stack
• Secure: No root access required when building custom VPN servers
• Tun/Tap: L3 and L2 hooks using TunInterface and TapInterface
• WS Tunnel: Tunnel packets to an internet-connected network using WebSockets
• v86: Communicate directly with an in-browser Linux VM via a NetworkAdapter

Installation

NPM

$ npm install --save tcpip

Yarn

$ yarn add tcpip

Usage

Basic

import { Stack, init } from 'tcpip';

async function run() {
  // Initialize the WASM module - call this at entrypoint
  await init();

  // Create a network stack
  const stack = new Stack();

  // A stack can have one or more network interfaces
  stack.createLoopbackInterface({
    ipAddress: '127.0.0.1/8',
  });

  // Node.js compatible `net` API available
  // (option to polyfill - see below)
  const { net } = stack;
  const server = net.createServer(80);
}

run();

Tun

import { Stack, init } from 'tcpip';

async function run() {
  await init();

  const stack = new Stack();

  // Tun interfaces provide hooks for L3 IP packets
  const tunInterface = stack.createTunInterface({
    ipAddress: '10.2.0.1/24',
  });

  // Capture outgoing IP packets
  tunInterface.on('packet', (packet) => {
    console.log(packet);
  });

  // Inject IP packets into the network stack
  tunInterface.injectPacket(myPacket);
}

run();

Tap

import { Stack, init } from 'tcpip';

async function run() {
  await init();

  const stack = new Stack();

  // Tap interfaces provide hooks for L2 ethernet frames
  const tapInterface = stack.createTapInterface({
    ipAddress: '10.1.0.1/24',
    macAddress: '0a:0a:0b:0b:0c:0c',
  });

  // Capture outgoing ethernet frames
  tapInterface.on('frame', (frame) => {
    console.log(frame);
  });

  // Inject ethernet frames into the network stack
  tapInterface.injectFrame(myFrame);
}

run();

Keep in mind this is all happening in user-space - no kernel-level network interfaces are created. If you want to connect your stack to an outside network, you can use WebSocket tunnels (browser) or any other transport (server).

Runtimes

tcpip.js relies on WebAssembly to run. Loading WASM isn't standardized yet across runtime environments, so some targets may require additional configuration. tcpip.js uses package exports to try to detect your runtime environment and load the appropriate initialize logic.

For all runtimes, you must call init() or initFrom() at your entrypoint to load tcpip.js's WASM module.

init()

If you are using a supported environment (eg. Webpack & Node), you can use init() to initialize the module:

import { init } from 'tcpip';

await init();

Note: Webpack requires additional configuration, see below.

initFrom()

If your environment doesn't support init() (eg. Deno), you can load the WASM file manually using initFrom():

import { Stack, initFrom } from 'https://esm.sh/tcpip@0.1.1';
import tcpipWasm from 'https://esm.sh/tcpip@0.1.1/dist/tcpip.wasm?module';

await initFrom(tcpipWasm);

Below are additional configuration instructions required for common runtimes/bundlers:

Webpack 5

Add a rule to load .wasm files as an asset/resource:

webpack.config.ts

import { Configuration } from 'webpack';

const config: Configuration = {
  module: {
    rules: [
      {
        test: /\.wasm/,
        type: 'asset/resource',
      },
    ],
  },
};

export default config;

Webpack 4

Install file-loader:

npm install --save-dev file-loader

or

yarn add -D file-loader

Add a rule to load .wasm files using the file-loader:

webpack.config.ts

import { Configuration } from 'webpack';

const config: Configuration = {
  module: {
    rules: [
      {
        test: /\.wasm/,
        use: [{ loader: 'file-loader' }],
      },
    ],
  },
};

export default config;

Node.js

No additional configuration is required to load in Node.js.

Deno

Currently you will need to manually load the WASM file and pass it into initFrom().

Using esm.sh:

index.ts

import { Stack, initFrom } from 'https://esm.sh/tcpip@0.1.1';
import tcpipWasm from 'https://esm.sh/tcpip@0.1.1/dist/tcpip.wasm?module';

await initFrom(tcpipWasm);

const stack = new Stack();

Then run:

$ deno run --allow-net index.ts

Polyfill net

You can polyfill the Node.js net module in the browser in order to run network requests through tcpip.js. This opens the doors to using server-side network libraries in the browser.

1. Install the polyfill:

   $ npm install --save @tcpip/polyfill

   or

   $ yarn add @tcpip/polyfill

2. Configure your bundler to resolve net using the polyfill:

   Webpack

   webpack.config.ts

   import { Configuration } from 'webpack';
   
   const config: Configuration = {
     // Don't forget to add wasm module rules
   
     resolve: {
       fallback: {
         net: require.resolve('@tcpip/polyfill/net'),
       },
     },
   };
   
   export default config;

   Be sure to add the appropriate module rules for your bundler as shown above under Runtimes.

3. Create a network stack and call polyfill() to attach that stack to the net module:

   import { polyfill } from '@tcpip/polyfill';
   import { Stack, init } from 'tcpip';
   
   async function run() {
     await init();
   
     const stack = new Stack();
   
     stack.createLoopbackInterface({
       ipAddress: '127.0.0.1/8',
     });
   
     polyfill(stack);
   }
   
   run();

4. Now any server-side library that imports net will use the polyfilled API and route packets through your stack.

   import { createServer } from 'net';
   
   // Creates a TCP server on your tcpip.js stack
   const server = createServer(80);

Note: This isn't a silver bullet - many server side libraries rely on more than just net (eg. fs, crypto, etc). You will need to polyfill the remaining modules on a case-by-case basis.

How does it work?

tcpip.js is built on gVisor's tcpip stack written in Go. It compiles to WASM then binds to JS classes and methods.

What is gVisor?

gVisor is an application kernel written in Go. It implements a large subset of Linux system calls completely in user-space, including a full TCP/IP stack. gVisor is used in production by Google in products like App Engine, Cloud Functions, and Cloud Run. It's also being used in some Kubernetes clusters as an extra security layer between containers.

Binding to JS via WASM

Code written in Go can be compiled to WASM using the GOARCH=wasm target. When combined with GOOS=js, you can use the syscall/js package to interact with JavaScript from Go.

tcpip.js is implemented using a hybrid language approach: The classes/interfaces are written in TypeScript and their methods are implemented in Go.

Roadmap

• LoopbackInterface/TunInterface/TapInterface
  • Basic POC
  • More options
• Node.js net API (TCP)
  • Basic POC
  • Polyfill
  • Complete implementation
• Node.js dgram API (UDP)
  • Basic POC
  • Polyfill
  • Complete implementation
• Node.js dns API
  • Basic POC
  • Polyfill
  • Complete implementation
• Node.js http API
  • Basic POC
  • Polyfill
  • Complete implementation
• v86 adapter
  • NetworkAdapter package
  • Example project
• WebSocket tunnel
  • Basic POC
  • Example project

License

MIT