Help me fix this Rust UDP problem :)

1_udp_listener.rb

require "socket"

rx_port = 2222
tx_port = 2223
host = "localhost"

socket = UDPSocket.new
socket.bind(host, rx_port)
socket.connect(host, tx_port)

puts "Just gonna chill until you send me something"
received = socket.recv(1024)
puts "Yay a packet! #{received}"

1_udp_sender.rb

require "socket"

rx_port = 2223
tx_port = 2222
host = "localhost"

socket = UDPSocket.new
socket.bind(host, rx_port)
socket.connect(host, tx_port)

socket.send("Hey dorks!", 0)

2_udp_listener.rs

use std::net::UdpSocket;

fn main() {
    let rx_port = 2222;
    let tx_port = 2223;
    let host = "localhost";

    let socket = UdpSocket::bind(format!("{}:{}", host, rx_port))
        .expect("Could not bind socket");

    socket.connect(format!("{}:{}", host, tx_port))
        .expect("Could not connect socket");

    let mut buffer = [0; 10];

    println!("{:?}", socket);
    println!("Just chillin' on the block");

    let data = socket.recv(&mut buffer);
    println!("Yay a packet! {:?}", data);
}

README.md

Rubyist attempts to port code to Rust. Send help.

Question

Why doesn't the Rust UDP listener programme work?

Context

I'm playing with some UDP socket code and also learning Rust.

What you're looking at

In this toy exmaple the listener programme should block waiting to receive a packet and when it does, print the result and exit.

The Ruby code works as I expect but the Rust version of the listener blocks forever apparently not receiving anything.

I've attempted to make these code samples as concise as possible.

Help appreciated!

It turns out that this is an IPv4 vs IPv6 issue. Rust creates an AF_INET6 socket even with localhost:2222 as the bind address.

Setting the bind address like so makes it work:

    let rx_socket_address = SocketAddr::new(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)), rx_port);

    let socket = UdpSocket::bind(rx_socket_address)
        .expect("Could not bind socket");