Dart Libp2p

A comprehensive Dart implementation of the libp2p networking stack, providing a modular and extensible foundation for building peer-to-peer applications.

🚀 Features

• Modular Architecture: Pluggable transports, security protocols, and stream multiplexers
• Multiple Transports: TCP and custom UDX (UDP-based) transport support
• Security: Noise protocol for encrypted and authenticated connections
• Stream Multiplexing: Yamux for efficient multi-stream communication
• Peer Discovery: mDNS and routing-based peer discovery mechanisms
• Protocol Support: Built-in support for Ping, Identify, and other core libp2p protocols
• Resource Management: Built-in protection against resource exhaustion
• Event System: Comprehensive event bus for monitoring network activity
• NAT Traversal: Hole punching and relay support for NAT traversal

📦 Installation

Add dart_libp2p to your pubspec.yaml:

dependencies:
  dart_libp2p: ^0.5.2

Then run:

dart pub get

🏃‍♂️ Quick Start

Here's a simple example of creating two libp2p nodes and connecting them:

import 'package:dart_libp2p/dart_libp2p.dart';
import 'package:dart_libp2p/config/config.dart' as p2p_config;
import 'package:dart_libp2p/core/crypto/ed25519.dart' as crypto_ed25519;
import 'package:dart_libp2p/core/multiaddr.dart';
import 'package:dart_libp2p/p2p/security/noise/noise_protocol.dart';
import 'package:dart_libp2p/p2p/transport/udx_transport.dart';
import 'package:dart_libp2p/p2p/transport/connection_manager.dart' as p2p_conn_manager;
import 'package:dart_udx/dart_udx.dart';

Future<Host> createHost({String? listen}) async {
  final keyPair = await crypto_ed25519.generateEd25519KeyPair();
  final udx = UDX();
  final connMgr = p2p_conn_manager.ConnectionManager();

  final options = <p2p_config.Option>[
    p2p_config.Libp2p.identity(keyPair),
    p2p_config.Libp2p.connManager(connMgr),
    p2p_config.Libp2p.transport(UDXTransport(connManager: connMgr, udxInstance: udx)),
    p2p_config.Libp2p.security(await NoiseSecurity.create(keyPair)),
    if (listen != null) p2p_config.Libp2p.listenAddrs([MultiAddr(listen)]),
  ];

  final host = await p2p_config.Libp2p.new_(options);
  await host.start();
  return host;
}

void main() async {
  final host1 = await createHost(listen: '/ip4/0.0.0.0/udp/0/udx');
  final host2 = await createHost(listen: '/ip4/0.0.0.0/udp/0/udx');

  print('Host 1: ${host1.id}');
  print('Host 2: ${host2.id}');

  await host1.connect(AddrInfo(host2.id, host2.addrs));
  print('Connected successfully!');

  await host1.close();
  await host2.close();
}

🏗️ Architecture

Dart Libp2p follows a layered architecture where each component provides services to the layer above it:

┌─────────────────────────────────────┐
│           Application               │
│        (Your Custom Protocols)      │
├─────────────────────────────────────┤
│              Host                   │
├─────────────────────────────────────┤
│           Network/Swarm             │
├─────────────────────────────────────┤
│            Upgrader                 │
├─────────────────────────────────────┤
│  Multiplexer (Yamux) │ Security     │
│                      │ (Noise)      │
├─────────────────────────────────────┤
│           Transport                 │
│        (TCP, UDX)                   │
└─────────────────────────────────────┘

Core Components

• Host: Central entry point that ties all components together
• Network/Swarm: Manages connections, peers, and upgrade lifecycle
• Upgrader: Handles security and multiplexing negotiation
• Transport: Establishes raw connections (TCP, UDX)
• Security: Encrypts and authenticates connections (Noise)
• Multiplexer: Enables multiple streams over single connections (Yamux)

🚛 Transports

TCP Transport

• Protocols: /ip4/tcp, /ip6/tcp
• Use Case: Reliable, widely available transport for most applications
• Best For: Data centers, servers with public IPs

UDX Transport

• Protocols: /ip4/udp/udx, /ip6/udp/udx
• Use Case: Custom UDP-based transport with built-in reliability
• Best For: NAT traversal, hole punching, peer-to-peer connections

Note: This implementation does not support QUIC. Instead, we've opted for a custom dart-udx implementation that provides similar benefits for peer-to-peer networking.

🔐 Security

Dart Libp2p uses the Noise protocol for securing connections:

• Encryption: All communication is encrypted
• Authentication: Remote peer identity is verified
• Perfect Forward Secrecy: Session keys are ephemeral
• Handshake: Efficient key exchange and authentication

📚 Documentation

For detailed documentation, visit the docs directory:

• Getting Started: Step-by-step setup guide
• Architecture: Detailed architecture overview
• Configuration: Configuration options
• Host: Host component documentation
• Transports: Transport layer details
• Security: Security protocol information
• Multiplexing: Stream multiplexing
• Protocols: Built-in protocol documentation
• Peerstore: Peer information management
• Event Bus: Event system documentation
• Resource Manager: Resource protection
• Cookbook: Practical examples and recipes

🧪 Examples

Check out the examples directory for working examples:

Example	Type	Description	Key Features
echo_basic	Basic	Simple echo server/client	One-way messaging, connection basics
chat_mdns	Advanced	mDNS-enabled P2P chat	mDNS discovery, multi-peer chat, zero-config networking

Featured Example: mDNS Chat

The chat_mdns example demonstrates mDNS service discovery using the mdns_dart package:

• ✅ Real mDNS service advertisement (not fake lookup calls)
• ✅ Actual network-level discovery (broadcasts to 224.0.0.251:5353)
• ✅ Zero-configuration networking (no fallback mechanisms needed)
• ✅ Cross-subnet support (works beyond localhost)

Run multiple instances to see real peer discovery in action:

# Terminal 1
dart run example/chat_mdns/main.dart

# Terminal 2  
dart run example/chat_mdns/main.dart

🧪 Testing

Run the test suite:

dart test

🤝 Contributing

We welcome contributions! Please see our contributing guidelines and code of conduct.

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Acknowledgments

• libp2p - The original protocol specification
• dart-udx - Custom UDP transport implementation
• mdns_dart - mDNS service advertisement and discovery
• The libp2p community for inspiration and guidance

🔗 Links

• libp2p.io - Official libp2p documentation
• Dart - Dart programming language
• pub.dev - Package on pub.dev