rustunnel/droid-wiki/systems/socks5-proxy.md

SOCKS5 proxy

The SOCKS5 module in src/socks5.rs implements RFC 1928 (SOCKS5 protocol) and RFC 1929 (username/password authentication).

Purpose

Handle the SOCKS5 handshake on the connector side, parse CONNECT requests, and resolve target addresses so that local applications can forward traffic through the tunnel.

Supported features

• CONNECT command only (no BIND or UDP)
• No-auth and username/password authentication methods
• IPv4 and domain name targets (no IPv6)
• Target DNS resolution on the connector side

Key abstractions

Type	File	Description
Socks5Target	src/socks5.rs	Enum: Ipv4(addr, port) or Domain { domain, port }
Socks5State	src/socks5.rs	State machine: ExpectGreeting → ExpectAuth → ExpectRequest → RequestReceived → Established → Closed
Socks5Error	src/socks5.rs	Error enum for malformed input, unsupported methods, and parse failures
parse_greeting	src/socks5.rs	Parse client greeting and choose auth method
parse_auth_request	src/socks5.rs	Parse username/password auth request
parse_connect_request	src/socks5.rs	Parse CONNECT request and extract target
resolve_target	src/socks5.rs	Async DNS resolution of a Socks5Target to a SocketAddr

Integration

The connector's run_socks5_proxy in src/tunnel.rs calls socks5_handshake (an async function in src/tunnel.rs that uses src/socks5.rs constants and helpers) for each incoming SOCKS5 connection. After handshake, it opens a stream via StreamMux::open_stream and forwards data bidirectionally.

Key source files

File	Purpose
src/socks5.rs	SOCKS5 protocol constants, parsing, target resolution
src/tunnel.rs	Async SOCKS5 handshake and proxy integration