socks-abstract5

A high-performance, RFC-compliant SOCKS5 proxy implementation in Rust.

Features

• Full RFC 1928 SOCKS5 protocol implementation
• Asynchronous architecture using Tokio
• Support for all SOCKS5 commands:
  • CONNECT
  • BIND
  • UDP ASSOCIATE
• Comprehensive address type support:
  • IPv4
  • IPv6
  • Domain names
• Zero-copy data transfer
• Robust error handling
• No external dependencies beyond Tokio and thiserror

Installation

Add this to your Cargo.toml:

[dependencies]
socks-abstract5 = "0.1.0"

Quick Start

Running as a Standalone Proxy

use socks_abstract5::Socks5Server;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let server = Socks5Server::new("127.0.0.1:1080").await?;
    server.run().await?;
    Ok(())
}

Using as a Library

use socks_abstract5::{Socks5Server, Result};

async fn start_proxy(bind_address: &str) -> Result<()> {
    let server = Socks5Server::new(bind_address).await?;
    server.run().await
}

Technical Documentation

Architecture

socks-abstract5 is built on a fully asynchronous architecture, leveraging Tokio for high-performance I/O operations. The implementation follows a modular design with clear separation of concerns:

• Protocol handling (authentication, command processing)
• Address resolution
• Data transfer
• Error management

Protocol Implementation

Authentication

Currently supports:

• No authentication (0x00)
• Extensible framework for adding additional authentication methods

Commands

1. CONNECT (0x01)

   • Establishes TCP connections to remote servers
   • Supports both direct IP connections and domain name resolution
   • Implements full duplex communication

2. BIND (0x02)

   • Supports reverse connection scenarios
   • Implements two-phase reply mechanism
   • Includes source address validation

3. UDP ASSOCIATE (0x03)

   • Creates UDP association for datagram transport
   • Maintains TCP control connection
   • Supports UDP relay functionality

Address Types

• IPv4 (0x01)
• Domain Name (0x03)
• IPv6 (0x04)

Error Handling

Comprehensive error handling using custom error types:

pub enum Error {
    Io(std::io::Error),
    InvalidVersion,
    AuthFailed,
    InvalidCommand(u8),
    InvalidAddrType(u8),
    ConnectionNotAllowed,
    NetworkUnreachable,
    HostUnreachable,
    ConnectionRefused,
    TtlExpired,
    ProtocolError,
    AddrTypeNotSupported,
}

Performance Considerations

• Zero-copy data transfer where possible
• Efficient memory usage with appropriate buffer sizes
• Asynchronous I/O for optimal resource utilization
• Connection pooling and reuse
• Minimal allocations during proxy operations

Configuration

Default configuration values:

const DEFAULT_BACKLOG: u32 = 1024;
const BUFFER_SIZE: usize = 8192;
const DEFAULT_TIMEOUT: Duration = Duration::from_secs(300);

Security Considerations

• No cleartext password authentication
• Connection validation
• Source address verification for BIND command
• Proper handling of connection timeouts
• Clean shutdown procedures

License

Mozilla Public License 2.0 (MPL-2.0)

Future Roadmap

• Authentication methods (Username/Password, GSSAPI)
• Configuration file support
• TLS/SSL support
• Connection pooling
• Advanced logging and metrics
• Rule-based access control
• HTTP/HTTPS proxy support
• Docker container support
• WebAssembly compilation target

Acknowledgments

This implementation follows the SOCKS Protocol Version 5 specification as defined in RFC 1928.