smol-rs / async-net

Async networking primitives for TCP/UDP/Unix communication

async-net

Async networking primitives for TCP/UDP/Unix communication.

This crate is an async version of std::net and std::os::unix::net.

Implementation

This crate uses async-io for async I/O and blocking for DNS lookups.

Examples

A simple UDP server that echoes messages back to the sender:

use async_net::UdpSocket;

let socket = UdpSocket::bind("127.0.0.1:8080").await?;
let mut buf = vec![0u8; 1024];

loop {
    let (n, addr) = socket.recv_from(&mut buf).await?;
    socket.send_to(&buf[..n], &addr).await?;
}

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

async-net's Issues

AsyncRead and AsyncWrite implementations for &TcpStream

I would like to understand if there a particular reason why the API for async_net::TcpStream does not mirror the API provided by std::TcpStream or Async by not implementing the AsyncRead and AsyncRead for shared references. I suppose I could still do this by using the Into<Arc<Async<TcpStream>>> implementation and using the implementations on that.

Provide a `TcpSocket` abstraction

I'd like to have a TcpSocket implementation like in Tokio (I don't really want to depend on the Tokio runtime just for this feature). I know that there are workarounds, but an async-first, easy to use implementation would be really appreciated.

Please provide into_inner methods

Types like Async<TcpListener> provide an into_inner() method to return the TcpListener, but async_net::TcpListener (AKA smol::net::TcpListener) does not expose that.

Indicate the MSRV

Mild testing on my own part indicated that the MSRV for this crate is 1.40.0 on Ubuntu 20.04 LTS. It would be nice if there were a badge on the README indicating this.

Use fully asynchronous implementation for DNS lookups

Right now we use blocking to run getaddrinfo, on a threadpool, but we can do better. I created async-dns as a way of doing DNS asynchronously. It needs improvements in robustness and optimization, but it usually works.

Another option would be trust-dns.

Peer credentials API

We should copy the API from the standard library (still an unstable feature at the time of writing this):

rust-lang/rust#42839

Unused fastrand dependency

I just grep'd through the source code and it looks like the fastrand dependency isn't being used anywhere. Its usage was probably removed in this commit. Should we take it out of Cargo.toml?