lib/virtual-net: tokio::net::lookup_host requires host:port format

[waynr]

This PR updates the call to tokio::net::lookup_host used by syscalls::wasix::wasi_resolve.

Prior to this PR when tokio::net::lookup_host is given a hostname without a port, name resolution fails with an Errno::Inval. When the port is added as shown in the tokio::net::lookup_host docs, it resolves successfully. This is kind of weird as it seems to me like the only thing necessary to look up a hostname should be the hostname itself -- the port shouldn't factor into it.

[waynr]

I verified this with a very simple reproduction of the problem i was seeing:

use tokio::net;

#[tokio::main]
async fn main() -> std::io::Result<()> {
    for addr in net::lookup_host("wasmer.io").await? {
        println!("socket address is {}", addr);
    }
    println!("Hello, world!");
    Ok(())
}

When I run this the output looks like

./target/debug/tokio-net-lookup-host
Error: Error { kind: InvalidInput, message: "invalid socket address" }

However, when I simply append a :0 to the host string it works:

use tokio::net;

#[tokio::main]
async fn main() -> std::io::Result<()> {
    for addr in net::lookup_host("wasmer.io:0").await? {
        println!("socket address is {}", addr);
    }
    println!("Hello, world!");
    Ok(())
}

./target/debug/tokio-net-lookup-host
socket address is 172.64.80.1:0
socket address is [2606:4700:3031::6815:16cc]:0
socket address is [2606:4700:3033::ac43:ceeb]:0
Hello, world!

[theduke]

@waynr

I think my intution was correct, our current Rust code just passes along the full string, while the regular implementation instead splits the string into port and hostname.

regular impl: https://github.com/wasix-org/rust/blob/43c52b0df5cad82411c989bf7228179585e4f494/library/std/src/sys_common/net.rs#L190

wasix impl: https://github.com/wasix-org/rust/blob/43c52b0df5cad82411c989bf7228179585e4f494/library/std/src/sys/wasix/net.rs#L1335

Note that the syscall impl in wasmer then replaces a 0 port with None, so it works out in the end.

Just need to fix the impl in Rust .