Vortex Protocol

Introduction

Vortex protocol is a high-performance peer-to-peer (P2P) file transfer protocol implementation in Rust, designed as part of the Dragonfly project. It utilizes the TLV (Tag-Length-Value) format for efficient and flexible data transmission, making it ideal for large-scale file distribution scenarios.

Features

• Efficient TLV Protocol: Optimized for fast serialization and deserialization of data packets.
• Large File Support: Handles piece sizes up to 1 GiB and value fields up to 4 GiB.
• Memory Safety: Built in Rust with zero-cost abstractions and memory safety guarantees.
• High Performance: Designed for high-throughput file transfer scenarios.
• Extensible Design: Reserved tags for future protocol extensions like compression and encryption.

Usage

Every TLV value implements Message, which encodes into any BufMut and decodes from a byte slice. encode_packet prepends the packet header; Vortex::decode parses a whole packet.

use bytes::BytesMut;
use vortex_protocol::tlv::download_piece::DownloadPiece;
use vortex_protocol::{Message, Vortex, HEADER_SIZE};

let request = DownloadPiece::new("a".repeat(64), 1);
let mut buffer = BytesMut::with_capacity(HEADER_SIZE + request.encoded_len());
request.encode_packet(&mut buffer);

match Vortex::decode(&buffer)? {
    Vortex::DownloadPiece(header, request) => println!("{} {:?}", header.length(), request),
    packet => println!("unexpected packet {packet:?}"),
}

The wire format is stable across releases: peers running different versions of the crate interoperate, and tests/wire_format.rs pins the bytes produced by earlier releases.

Documentation

For details, please see the specification.

Benchmarking

Vortex protocol includes benchmarks for encoding and decoding every message and whole packets:

# Run all benchmarks
cargo bench

# Run the benchmarks of one message
cargo bench PieceContent