[WIP] - Forward reuse_port and reuse_addr when it's possible to

[rodjjo]

The runtime exposes functions to allow us to set SO_REUSEADDR and SO_REUSEPORT, however it's not working:

wasmer run --net examples/rust_udp/target/wasm32-wasmer-wasi/debug/udp_example.rustc.wasm
Starting UDP server
Binding to 0.0.0.0:8080
Error: Os { code: 3, kind: AddrInUse, message: "Address in use" }

The example code:

use tokio::net::UdpSocket;
use std::io;
use std::net::{SocketAddr};
use socket2::{Socket, Domain, Type};


#[tokio::main]
async fn main() -> io::Result<()> {
    println!("Starting UDP server");
    let std_sock = Socket::new(Domain::IPV4, Type::DGRAM, None)?;
    std_sock.set_reuse_address(true)?;

    println!("Binding to 0.0.0.0:8080");

    let address: SocketAddr = "0.0.0.0:8080".parse().unwrap();
    let address = address.into();
    std_sock.bind(&address)?;
   
    let sock = UdpSocket::from_std(std_sock.into())?;

    let mut buf = [0; 1024];
    loop {
        let (len, addr) = sock.recv_from(&mut buf).await?;
        println!("{:?} bytes received from {:?}", len, addr);

        let len = sock.send_to(&buf[..len], addr).await?;
        println!("{:?} bytes sent", len);
    }
}

This pull request intend to solve issue-5247

I need help to understand the impact of the changes on other platforms, I tested it in my use case and I was able to reuse the address when I ran Wasmer on Ubuntu.

[rodjjo]

@maminrayej what do you think, would be that the way ?

[maminrayej]

LGTM, although it needs a test to pin this behavior. You could try to add a WASIX test by looking at other tests and how they are set up.

As a bonus (not required for the PR to be merged), you could fix the same issue in other places such as listen_tcp.

[syrusakbary]

Any reason why we are not using the same logic for Windows? It seems that the API for socket reusing is also available there, so the more commonalities between systems, the better

[syrusakbary]

Hey @rodjjo, we are happy to merge the PR once we make the logic with Windows similar as with Unix and hopefully a test that verifies the fix to make sure we are shielded of this issue in the future.

Let us know if you need any help with that