http-tunnel

Overview

An implementation of HTTP Tunnel in Rust, which can also function as a TCP proxy.

The core code is entirely abstract from the tunnel protocol or transport protocols. In this example, it supports both HTTP and HTTPS with minimal additional code.

Please note, this tunnel doesn't allow tunneling of plain text over HTTP tunnels (only HTTPS connections can be tunneled). If you need this functionality you need to build the http-tunnel with the plain_text feature:

cargo build --release --features plain_text

E.g. it can be extended to run the tunnel over QUIC+HTTP/3 or connect to another tunnel (as long as AsyncRead + AsyncWrite is satisfied for the implementation).

You can check benchmarks.

Read more about the design.

Quick overview of source files

• configuration.rs - contains configuration structures + a basic CLI
  • see config/ with configuration files/TLS materials
• http_tunnel_codec.rs - a codec to process the initial HTTP request and encode a corresponding response.
• proxy_target.rs - an abstraction + basic TCP implementation to connect target servers.
  • contains a DNS resolver with a basic caching strategy (cache for a given TTL)
• relay.rs - relaying data from one stream to another, tunnel = upstream_relay + downstream_relay
  • also, contains basic relay_policy
• tunnel.rs - a tunnel. It's built from:
  • a tunnel handshake codec (e.g. HttpTunnelCodec)
  • a target connector
  • client connection as a stream
• main.rs - application. May start HTTP or HTTPS tunnel (based on the command line parameters).
  • emits log to logs/application.log (log/ contains the actual output of the app from the browser session)
  • metrics to logs/metrics.log - very basic, to demonstrate the concept.`

Run demo

Install via cargo:

cargo install http-tunnel

Now you can start it without any configuration:

$ http-tunnel --bind 0.0.0.0:8080 http

There are three modes.

• HTTPS:

$ http-tunnel --config ./config/config.yaml \
              --bind 0.0.0.0:8443 \
              https --pk "./config/domain.pfx" --password "6B9mZ*1hJ#xk"

• HTTP:

$ http-tunnel --config ./config/config-browser.yaml --bind 0.0.0.0:8080 http

• TCP Proxy:

$ http-tunnel --config ./config/config-browser.yaml --bind 0.0.0.0:8080 tcp --destination $REMOTE_HOST:$REMOTE_PORT

Testing with a browser (HTTP)

In Firefox, you can set the HTTP proxy to localhost:8080. Make sure you run it with the right configuration:

https://support.mozilla.org/en-US/kb/connection-settings-firefox

(use HTTP Proxy and check "use this proxy for FTP and HTTPS")

$ ./target/release/http-tunnel --config ./config/config-browser.yaml --bind 0.0.0.0:8080 http

Testing with cURL (HTTPS)

This proxy can be tested with cURL:

Add simple.rust-http-tunnel.org' to /etc/hosts:

$ echo '127.0.0.1       simple.rust-http-tunnel.org' | sudo tee -a /etc/hosts

Then try access-listed targets (see ./config/config.yaml), e.g:

curl -vp --proxy https://simple.rust-http-tunnel.org:8443  --proxy-cacert ./config/domain.crt https://www.wikipedia.org

You can also play around with targets that are not allowed.

Privacy

The application cannot see the plaintext data.

The application doesn't log any information that may help identify clients (such as IP, auth tokens). Only general information (events, errors, data sizes) is logged for monitoring purposes.

DDoS protection

• Slowloris attack (opening tons of slow connections)
• Sending requests resulting in large responses

Some of them can be solved by introducing rate/age limits and inactivity timeouts.

Build

Install cargo - follow these instructions

On Debian to fix OpenSSL build issue:

sudo apt-get install pkg-config libssl-dev

Installation

On MacOS:

curl https://sh.rustup.rs -sSf | sh
cargo install http-tunnel
http-tunnel --bind 0.0.0.0:8080 http

On Debian based Linux:

curl https://sh.rustup.rs -sSf | sh
sudo apt-get -y install gcc pkg-config libssl-dev
cargo install http-tunnel
http-tunnel --bind 0.0.0.0:8080 http