rust-utp

A Micro Transport Protocol library implemented in Rust.

The Micro Transport Protocol is a reliable protocol with ordered delivery built over UDP. Its congestion control algorithm is LEDBAT, which tries to use as much unused bandwidth as it can but readily yields to competing flows, making it useful for bulk transfers without introducing congestion in the network.

The current implementation is somewhat incomplete, lacking a complete implementation of congestion control. However, it does support packet loss detection (except by timeout) the Selective Acknowledgment extension, handles unordered and duplicate packets and presents a stream interface (UtpStream).

Building

sh git clone https://github.com/meqif/rust-utp.git cd rust-utp cargo test cargo build --release

Note that non-release builds are much slower.

Usage

Check the examples directory. The simplest example would be:

```rust,no_run extern crate utp;

use utp::UtpStream; use std::io::{Read, Write};

fn main() { // Connect to an hypothetical local server running on port 8080 let addr = "127.0.0.1:8080"; let mut stream = match UtpStream::connect(addr) { Ok(stream) => stream, Err(e) => panic!("{}", e), };

// Send a string
match stream.write("Hi there!".as_bytes()) {
    Ok(_) => (),
    Err(e) => println!("Write failed with {}", e)
}

// Close the stream
match stream.close() {
    Ok(()) => println!("Connection closed"),
    Err(e) => println!("{}", e)
}

} ```

To implement

[x] congestion control
[x] proper connection closing
- [x] handle both RST and FIN
- [x] send FIN on close
- [x] automatically send FIN on drop if not already closed
[x] sending RST on mismatch
[x] setters and getters that hide header field endianness conversion
[x] SACK extension
[ ] handle packet loss
- [x] send triple-ACK to re-request lost packet (fast resend request)
- [x] rewind send window and resend in reply to triple-ACK (fast resend)
- [ ] resend packet on ACK timeout
[x] stream interface
[x] handle unordered packets
[ ] path MTU discovery
[x] duplicate packet handling

License

This library is distributed under similar terms to Rust: dual licensed under the MIT license and the Apache license (version 2.0).