s2n-quic

s2n-quic is a Rust implementation of the IETF QUIC protocol, featuring:

• a simple, easy-to-use API. See an example of an s2n-quic echo server built with just a few API calls
• high configurability using providers for granular control of functionality
• extensive automated testing, including fuzz testing, integration testing, unit testing, snapshot testing, efficiency testing, performance benchmarking, interoperability testing and more
• integration with s2n-tls, AWS's simple, small, fast and secure TLS implementation, as well as rustls
• thorough compliance coverage tracking of normative language in relevant standards
• and much more, including CUBIC congestion controller support, packet pacing, Generic Segmentation Offload support, Path MTU discovery, and unique connection identifiers detached from the address

See the API documentation, examples, and s2n-quic Guide to get started with s2n-quic.

Installation

s2n-quic is available on crates.io and can be added to a project like so:

[dependencies]
s2n-quic = "1"

NOTE: On unix-like systems, s2n-tls will be used as the default TLS provider. On linux systems, aws-lc-rs will be used for cryptographic operations. A C compiler and CMake may be required on these systems for installation.

Example

The following implements a basic echo server and client. The client connects to the server and pipes its stdin on a stream. The server listens for new streams and pipes any data it receives back to the client. The client will then pipe all stream data to stdout.

Server

// src/bin/server.rs
use s2n_quic::Server;
use std::{error::Error, path::Path};

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    let mut server = Server::builder()
        .with_tls((Path::new("cert.pem"), Path::new("key.pem")))?
        .with_io("127.0.0.1:4433")?
        .start()?;

    while let Some(mut connection) = server.accept().await {
        // spawn a new task for the connection
        tokio::spawn(async move {
            while let Ok(Some(mut stream)) = connection.accept_bidirectional_stream().await {
                // spawn a new task for the stream
                tokio::spawn(async move {
                    // echo any data back to the stream
                    while let Ok(Some(data)) = stream.receive().await {
                        stream.send(data).await.expect("stream should be open");
                    }
                });
            }
        });
    }

    Ok(())
}

Client

// src/bin/client.rs
use s2n_quic::{client::Connect, Client};
use std::{error::Error, path::Path, net::SocketAddr};

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    let client = Client::builder()
        .with_tls(Path::new("cert.pem"))?
        .with_io("0.0.0.0:0")?
        .start()?;

    let addr: SocketAddr = "127.0.0.1:4433".parse()?;
    let connect = Connect::new(addr).with_server_name("localhost");
    let mut connection = client.connect(connect).await?;

    // ensure the connection doesn't time out with inactivity
    connection.keep_alive(true)?;

    // open a new stream and split the receiving and sending sides
    let stream = connection.open_bidirectional_stream().await?;
    let (mut receive_stream, mut send_stream) = stream.split();

    // spawn a task that copies responses from the server to stdout
    tokio::spawn(async move {
        let mut stdout = tokio::io::stdout();
        let _ = tokio::io::copy(&mut receive_stream, &mut stdout).await;
    });

    // copy data from stdin and send it to the server
    let mut stdin = tokio::io::stdin();
    tokio::io::copy(&mut stdin, &mut send_stream).await?;

    Ok(())
}

Minimum Supported Rust Version (MSRV)

s2n-quic will maintain a rolling MSRV (minimum supported rust version) policy of at least 6 months. The current s2n-quic version is not guaranteed to build on Rust versions earlier than the MSRV.

The current MSRV is 1.88.0.

Supported Operating Systems

s2n-quic can be built on Linux, MacOS, and Windows. s2n-quic requires Linux kernel version 5.0 or later. Earlier Linux kernel versions are not supported as they lack the Generic Segmentation Offload (GSO) capabilities required by s2n-quic.

Security issue notifications

If you discover a potential security issue in s2n-quic we ask that you notify AWS Security via our vulnerability reporting page. Please do not create a public github issue.

If you package or distribute s2n-quic, or use s2n-quic as part of a large multi-user service, you may be eligible for pre-notification of future s2n-quic releases. Please contact s2n-pre-notification@amazon.com.

License

This project is licensed under the Apache-2.0 License.