ws-tcp-proxy

Bidirectional proxy that bridges raw TCP and WebSocket binary frames.

Features

• tcp-ws: TCP inbound to WebSocket outbound (binary frames).
• ws-tcp: WebSocket inbound to TCP outbound (binary frames).
• Optional HAProxy v2 header injection for ws-tcp using cf-connecting-ip.

Build

cargo build --release

Usage

TCP → WebSocket

cargo run -- tcp-ws 127.0.0.1:9000 ws://127.0.0.1:8080

WebSocket → TCP

cargo run -- ws-tcp 127.0.0.1:8080 127.0.0.1:9000

WebSocket → TCP with HAProxy v2

cargo run -- ws-tcp 127.0.0.1:8080 127.0.0.1:9000 --haproxy-v2

Notes:

• In ws-tcp mode, the proxy inspects the WebSocket handshake for the cf-connecting-ip header.
• When --haproxy-v2 is enabled, the proxy sends a HAProxy v2 PROXY header to the TCP backend using the cf-connecting-ip value if present, otherwise the remote socket address.
• If the header IP is IPv6 and the backend connection is IPv4, the proxy maps IPv4 to an IPv6-mapped address to produce a valid v2 header.

Modes

• tcp-ws <listen_addr> <ws_url>
• ws-tcp <listen_addr> <tcp_target> [--haproxy-v2 | --haproxy]

Example topology

[TCP client] -> (tcp-ws) -> [WebSocket server]
[WebSocket client] -> (ws-tcp) -> [TCP server]

Fun fact

This project was originally called WebSocketMC.