Binding to "any" address does not work as expected

[chrysn]

At least on UDP sockets, calling socket.bind(IpEndpoint::from(core::net::SocketAddr::parse("0.0.0.0:1234").unwrap())) does not behave as expected: It seems to bind not at all, whereas it should bind to that port on any IP address.

There is a workaround of doing socket.bind(1234) -- that's fine when an application calls it directly, but needs a workaround such as

        let bind_to = IpEndpoint::from(local);
        if bind_to.addr.is_unspecified() {
            socket.bind(bind_to.port)?;
        } else {
            socket.bind(bind_to)?;
        }

(And sorry for the IPv4 examples, we're working to have v6 in parallel)

I can most probably provide a PR later; right now, this serves to document the workaround.

[Dirbaio]

this is intended behavior, see #981

[chrysn]

Fine with me, sorry for the duplicate.

That's an argument that will also be helpful in rust-embedded-community/embedded-nal#92 -- indicating that the core types are a tad too far on the "POSIX sockets" side of things, with more idiomatic expressions around (esp. when the IP addresses are expressed in such a way that they have a zero niche).