FastLink

High-performance P2P networking protocol suite

---

🚀 Project Introduction

FastLink is a high-performance P2P networking protocol suite providing:

• Mother Protocol: Unified abstraction layer, time synchronization, NAT parameter library
• P2P Protocol: Enhanced NAT traversal with BirthdayPunch algorithm, connection state machine
• Server Protocol: Five-dimensional weighted intelligent routing
• Swift Tunnel: Anti-DPI obfuscated transport
• Games Protocol: Low-latency game networking
• Aztec Protocol: Enterprise-grade distributed Mesh networking
• Chat Protocol: Zero-server end-to-end encrypted messaging

---

🏃 Quick Start

# Clone repository
git clone https://github.com/StarsailsClover/FastLink.git
cd FastLink
# Build project
cargo build --release
# Run tests
cargo test# Run CLI
cargo run --bin fastlink-cli

---

🏗️ Project Structure

FastLink/
├── apps/fastlink-cli/ # CLI application
├── core/ # Core libraries
│ ├── mother-protocol/ # Mother protocol
│ ├── libfastcrypto/ # Crypto library
│ ├── libcommon/ # Common components
│ ├── libomnilink/ # P2P omnilink (NAT traversal)
│ ├── libfasttransport/ # Transport layer
│ ├── libfastdht/ # DHT
│ ├── libantidpi/ # Anti-DPI
│ └── libnetworktest/ # Network testing
├── protocols/ # Protocol implementations
│ ├── fastlink-p2p/ # P2P protocol
│ ├── fastlink-server/ # Server protocol
│ ├── fastlink-swift/ # Swift tunnel
│ ├── fastlink-games/ # Game networking
│ ├── fastlink-aztec/ # Enterprise Mesh
│ └── fastlink-chat/ # Encrypted messaging
└── tools/ # Testing and debugging tools

---

🔥 Core Features

🎂 BirthdayPunch NAT Traversal (NEW)

Multi-strategy NAT traversal with intelligent fallback:

Strategy	NAT Type	Success Rate	Description
Direct	Open	100%	Direct connection
STUN	Full/Restricted Cone	>90%	Standard hole punching
BirthdayPunch	Symmetric	~60%	Port prediction via birthday paradox
TURN	All types	99%	Relay fallback

Key improvements:

• ✅ BirthdayPunch Algorithm: Based on birthday paradox, predicts NAT port allocation
• ✅ Adaptive Strategy Selection: Automatically chooses best method based on detected NAT type
• ✅ Symmetric NAT Support: Improved from <50% to ~60% success rate
• ✅ TURN Fallback: Guaranteed connectivity when direct methods fail

How BirthdayPunch Works

1. Detect NAT type via STUN servers
2. If Symmetric NAT detected:
- Analyze port allocation pattern (sequential/random/delta)
- Generate predicted port candidates using birthday paradox
- Attempt connection to predicted ports
3. If all methods fail, fall back to TURN relay

📊 NAT Traversal Success Rates

NAT Type	Best Strategy	Expected Success
Open Internet	Direct	100%
Full Cone	STUN	>95%
Restricted Cone	STUN	>90%
Port Restricted	STUN/BirthdayPunch	>85%
Symmetric	BirthdayPunch	~60%

Note: Actual success depends on ISP and router configuration

Five-Dimensional Weighted Routing

W = 0.4·Latency + 0.3·Loss + 0.1·Hops + 0.15·ISP + 0.05·Geo

6-State Connection State Machine

Idle → Detect → PreMap → Punch → Connected/Disconnected
↓ ↓ ↓
Role Swap Failure Report

---

🛠️ Technical Stack

Component	Technology	Purpose
Core	Rust + Tokio	Async runtime
Crypto	x25519-dalek, ed25519-dalek	Key exchange & signatures
Encryption	ChaCha20-Poly1305	AEAD symmetric encryption
Hash	Blake3	Fast cryptographic hashing
NAT	STUN/TURN + BirthdayPunch	NAT traversal
DHT	Kademlia variant	Peer discovery

---

📦 Installation

Requirements

• Rust 1.75+
• Cargo

Build

git clone https://github.com/StarsailsClover/FastLink.git
cd FastLink
cargo build --release

Run

# CLI help
cargo run --bin fastlink-cli -- --help
# Start P2P node
cargo run --bin fastlink-cli -- node start
# Run tests
cargo test --workspace

---

🤝 Contributing

Issues and Pull Requests are welcome!

---

📜 License

MIT OR Apache-2.0

---

📧 Contact

Email: sailshuang@gmail.com
GitHub: @StarsailsClover

---

🙏 Acknowledgments

• BirthdayPunch algorithm inspired by academic research on NAT traversal
• STUN/TURN protocols from RFC 5389/5766
• ICE framework from RFC 5245