Review: how to listen on both ipv4 and ipv6?

[carneeki]

In #456, @nbari asked how it is possible to listen on both ipv4 and ipv6 at the same time, and the issue stalled.

I have a main.rs file that is something like this:

async fn main() {
    let config = Some(configuration); // getting config from a .toml file
    let routes = warp::get(); // snipping the routes for brevity

    let listen4 = SocketAddr::from_str(config.ipv4).expect('Invalid ipv4 config');
    let listen6 = SocketAddr::from_str(config.ipv6).expect('Invalid ipv6 config');

    let server4 = warp::serve(routes.clone()).run(listen4);
    let server6 = warp::serve(routes.clone()).run(listen6);

    futures::join!(server4, server6);
}

This seems to be working, but I'm not sure if this is a good way to do what was desired and would like some feedback on how it could be done.

Originally posted by @nbari in #456 (comment)

Thanks!

EDIT: I forgot to mention, I'm doing this in stable rather than nightly.

[jxs]

you can also bind to both Ipv6 and Ipv4:

    let addr = IpAddr::from_str("::0").unwrap();
    warp::serve(endpoints).run((addr, 3030)).await;

[nbari]

hi @jxs using let addr = IpAddr::from_str("::0").unwrap(); I get:

no variant or associated item named `from_str` found for enum `std::net::IpAddr` in the current scope

[jxs]

you need to import it:

use std::net::IpAddr;
use std::str::FromStr;

[cmcqueen]

@jxs wrote:

you can also bind to both Ipv6 and Ipv4:

   let addr = IpAddr::from_str("::0").unwrap();
   warp::serve(endpoints).run((addr, 3030)).await;

This depends on whether the OS you're running on has the IPV6_V6ONLY socket option turned on or off by default.

I'm doing the above, running on a Linux system that is configured for net.ipv6.bindv6only = 0, so it works.

But I have colleagues testing a Windows build, and are reporting that they can't connect to eg 127.0.0.1.

So I'm trying to work out the most reliable solution that works for both Linux, regardless of net.ipv6.bindv6only, and for Windows.

It is possible to use the socket2 crate to explicitly control the IPV6_V6ONLY option (something like this, although that should change to listening on just [::] to work), but I haven't yet figured out how to set up such a socket with warp yet.

[cmcqueen]

This has been asked on StackOverflow: How to listen on multiple ports with warp?