Haxial KDX - C/C++ Implementation

A clean-room, binary-compatible reimplementation of Haxial KDX client/server/tracker system through reverse engineering.

Project Overview

Haxial KDX is a vintage client/server communication platform with features including:

• Multi-user chat (public and private)
• File sharing and transfer
• News/message boards
• User management and permissions
• Tracker system for server discovery

This project aims to create a modern, cross-platform implementation by reverse-engineering the original KDX protocol from binaries.

Architecture

Components

• libhaxial (LGPL-3.0): Core protocol library in C

  • Pascal string implementation
  • Packet encoding/decoding
  • Connection management
  • Transaction handling
  • Cross-platform socket abstraction

• haxial-server (GPL-3.0): Server daemon in C

  • Multi-client connection handling
  • User authentication
  • File management
  • Chat and news systems

• haxial-tracker (GPL-3.0): Tracker service in C

  • Server registration and discovery
  • Server list management
  • Heartbeat monitoring

• haxial-client (GPL-3.0): GUI client in C++23 + Qt 6

  • Modern Qt 6 interface
  • Server browser
  • Chat interface
  • File transfer UI
  • News reader

Platform Support

• Linux: glibc-based distributions (POSIX sockets, pthread)
• macOS: 11.0+ (Intel and Apple Silicon)
• Windows: Windows 10+ with UCRT (Winsock2, Win32 threads)

Building

Prerequisites

• CMake 3.20+
• C11 compiler (GCC, Clang, or MSVC)
• C++23 compiler (GCC 13+, Clang 16+, or MSVC 2022)
• Qt 6.2+ (for client only)
• Ninja (recommended) or Make

Quick Start

# Configure (Linux)
cmake --preset linux-glibc-debug

# Build
cmake --build build/linux-glibc-debug

# Run server
./build/linux-glibc-debug/server/haxial-server

# Run client
./build/linux-glibc-debug/client/haxial-client

CMake Presets

Available presets:

• linux-glibc-debug / linux-glibc-release
• macos-debug / macos-release
• windows-ucrt-debug / windows-ucrt-release

Protocol Reverse Engineering

The KDX protocol is being reverse-engineered using Ghidra. See:

• AGENTS.md: Ghidra MCP analysis guidelines
• docs/protocol/: Protocol documentation
• docs/protocol/findings/: Per-binary analysis notes

Key Protocol Features

• Pascal Strings: 1-byte length prefix + data (no null terminator)
• Binary Packets: Fixed header + TLV parameter blocks
• Transaction-Based: Request/response model with transaction IDs
• TCP-Based: No encryption in original protocol

Development Status

🚧 Early Development - Protocol analysis in progress

• Project structure and build system
• Documentation framework
• Protocol analysis (KDXServer.lexe, KDX Client)
• libhaxial implementation
• Server implementation
• Tracker implementation
• Client implementation

License

• libhaxial: LGPL-3.0-or-later (allows use in proprietary software)
• Server/Tracker/Client: GPL-3.0-or-later

See LICENSE-LGPL-3.0 and LICENSE-GPL-3.0.

Contributing

This is a reverse engineering project focused on protocol compatibility. Contributions welcome for:

• Binary analysis with Ghidra
• Protocol documentation
• Implementation of documented features
• Testing with original KDX binaries
• Cross-platform compatibility

Disclaimer

This is an independent reimplementation through reverse engineering for interoperability and preservation purposes. Not affiliated with original Haxial KDX developers.

Resources

• Original software: Haxial KDX (vintage Mac/Windows)
• Analysis tool: Ghidra 11.0+
• Build system: CMake 3.20+
• UI framework: Qt 6

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Current Focus: Analyzing KDXServer.lexe to document packet format and protocol constants.