feat: ✨ udp hole puncher

.gitignore

@@ -18,4 +18,8 @@ Cargo.lock
 #  be found at https://github.com/github/gitignore/blob/main/Global/JetBrains.gitignore
 #  and can be added to the global gitignore or merged into this file.  For a more nuclear
 #  option (not recommended) you can uncomment the following to ignore the entire idea folder.
-#.idea/
+#.idea/
+
+# Added by cargo
+
+/target

Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "rust-udp-hole-puncher"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

src/main.rs

@@ -0,0 +1,105 @@
+use std::{io, net::UdpSocket};
+
+fn main() {
+    println!("Hello, world!");
+    println!("Addr");
+    let mut addr = String::default();
+    io::stdin().read_line(&mut addr).unwrap();
+    let addr = addr.trim_end();
+    println!("Server | Client");
+    let mut input = String::default();
+    io::stdin().read_line(&mut input).unwrap();
+    let input = input.trim_end();
+    match input {
+        "server" | "Server" | "SERVER" | "s" => server(addr),
+        "client" | "Client" | "CLIENT" | "c" => client(addr),
+        _ => {}
+    }
+}
+
+fn server(addr: &str) {
+    let udp_socket = match UdpSocket::bind(addr) {
+        Ok(udp_socket) => udp_socket,
+        Err(err_val) => {
+            eprintln!("{}", err_val);
+            return;
+        }
+    };
+    let mut buffer = [0_u8; 100];
+    let mut peers = vec![];
+    for _ in 0..2 {
+        let (data_size, peer) = match udp_socket.recv_from(&mut buffer) {
+            Ok((data_size, peer)) => (data_size, peer),
+            Err(err_val) => {
+                eprintln!("{}", err_val);
+                return;
+            }
+        };
+        peers.push(format!("{}:{}", peer.ip(), peer.port()));
+        let data = buffer.split_at(data_size).0;
+        let message = String::from_utf8_lossy(data).into_owned();
+        println!("{}:{} = {}", peer.ip(), peer.port(), message);
+    }
+
+    match udp_socket.send_to(peers[1].as_bytes(), &peers[0]) {
+        Ok(_) => println!("Sent First"),
+        Err(err_val) => {
+            eprintln!("{}", err_val);
+            return;
+        }
+    };
+    match udp_socket.send_to(peers[0].as_bytes(), &peers[1]) {
+        Ok(_) => println!("Sent Second"),
+        Err(err_val) => eprintln!("{}", err_val),
+    };
+}
+
+fn client(addr: &str) {
+    let udp_socket = match UdpSocket::bind(addr) {
+        Ok(udp_socket) => udp_socket,
+        Err(err_val) => {
+            eprintln!("{}", err_val);
+            return;
+        }
+    };
+    match udp_socket.send_to(
+        "Hello Sir".as_bytes(),
+        "0.0.0.0", /* I change it with public address */
+    ) {
+        Ok(_) => {}
+        Err(err_val) => {
+            eprintln!("{}", err_val);
+        }
+    };
+    let mut buffer = [0_u8; 100];
+    let (data_size, peer) = match udp_socket.recv_from(&mut buffer) {
+        Ok((data_size, peer)) => (data_size, peer),
+        Err(err_val) => {
+            eprintln!("{}", err_val);
+            return;
+        }
+    };
+    let data = buffer.split_at(data_size).0;
+    let message = String::from_utf8_lossy(data).into_owned();
+    println!("{}:{} = {}", peer.ip(), peer.port(), message);
+
+    match udp_socket.send_to("Hello Dear".as_bytes(), message) {
+        Ok(_) => {}
+        Err(err_val) => {
+            eprintln!("{}", err_val);
+            return;
+        }
+    };
+
+    let mut buffer = [0_u8; 100];
+    let (data_size, peer) = match udp_socket.recv_from(&mut buffer) {
+        Ok((data_size, peer)) => (data_size, peer),
+        Err(err_val) => {
+            eprintln!("{}", err_val);
+            return;
+        },
+    };
+    let data = buffer.split_at(data_size).0;
+    let message = String::from_utf8_lossy(data).into_owned();
+    println!("{}:{} = {}", peer.ip(), peer.port(), message);
+}