Now the code is cleaner, and we can configure the server a bit

src/main.rs

@@ -0,0 +1,31 @@
+use std::net::UdpSocket;
+use std::io::stdin;
+
+fn main() {
+    let server_address: String = get_server_address();
+    listen(server_address);
+}
+
+fn get_server_address() -> String {
+    println!("Enter server address (format xxx.xxx.xxx.xxx:port)");
+    let mut server_address = String::new();
+    stdin().read_line(&mut server_address).expect("Reading the server address from input");
+    server_address = String::from(server_address.trim());
+    return server_address;
+}
+
+fn listen(server_address: String) {
+    println!("listening on {}", server_address);
+    loop {
+        let mut message: String = String::new();
+        let mut buf: [u8; 1024] = [0; 1024];
+        let socket: UdpSocket = UdpSocket::bind(server_address.clone()).expect("Error while binding the socket.");
+        let (num_bytes, src_addr) = socket.recv_from(&mut buf).expect("Error while receiving message");
+        message.push_str(std::str::from_utf8(&buf[..num_bytes]).expect("Invalid UTF-8 data"));
+        println!("{}:{}", src_addr.to_string(), message);
+
+        if message.trim() == "!STOP" {
+            return;
+        }
+    }
+}