add readme

README.md

@@ -0,0 +1,91 @@
+# DragonOS Network Subsystem Validation
+
+## How to run
+
+1. configure a bridge interface for testing
+```bash
+sudo brctl addbr br-tap0
+sudo ip addr add 192.168.213.1/24 dev br-tap0
+sudo ip link set dev br-tap0 up
+```
+
+2. build the binary and run it as root
+```bash
+cargo build
+sudo ./target/debug/berkeley-socket
+```
+
+3. check if the `tap0` interface is created
+```bash
+ip addr show tap0
+```
+
+4. create a tap interface and add it to the bridge
+```bash
+sudo brctl addif br-tap0 tap0
+```
+
+5. bring up all interfaces
+```bash
+sudo ip link set dev tap0 up
+```
+
+If you want to stop the main program, just `Ctrl+C` it. The tap interface will be removed automatically but the bridge will remain. So the next time just run the program again, and repeat step 4 and 5 to bring up the tap interface. 
+
+## How to test
+
+An example could be:
+```rust
+use std::{
+    io::{Read, Write},
+    net::UdpSocket,
+};
+
+fn make_udp_test() -> std::io::Result<()> {
+    // Create a UDP socket
+    let socket = UdpSocket::bind("192.168.213.1:12345")?;
+
+    // Message to send
+    let message = "helloworld";
+
+    // Target address (IP and port)
+    let target_address = "192.168.213.2:1234";
+
+    // Send the message
+    socket.send_to(message.as_bytes(), target_address)?;
+
+    println!("Sent '{}' to {}", message, target_address);
+
+    let mut buf = [0; 1024]; // Buffer to receive data
+    socket.recv(&mut buf)?;
+    let received_message = String::from_utf8_lossy(&buf);
+    println!("Received: {}", received_message);
+
+    Ok(())
+}
+
+fn make_tcp_test() -> std::io::Result<()> {
+    // Send a message
+    let message = "helloworld";
+    let target_address = "192.168.213.2:4321";
+    let mut stream = std::net::TcpStream::connect(target_address)?;
+    stream.write_all(message.as_bytes())?;
+    let mut buf = [0; 1024]; // Buffer to receive data
+    let _ = stream.read(&mut buf)?;
+    let received_message = String::from_utf8_lossy(&buf);
+    println!("Received: {}", received_message);
+
+    Ok(())
+}
+
+fn main() -> std::io::Result<()> {
+    // Call the function to create and use the UDP socket
+    make_udp_test()?;
+    // Call the function to create and use the TCP socket
+    make_tcp_test()?;
+
+    Ok(())
+}
+```
+
+Change the socket used in the main program and DIY your own test.

src/main.rs

@@ -23,7 +23,7 @@ fn make_udp_echo() {
         .unwrap();
     socket
         .connect(Endpoint::Ip(IpEndpoint::new(
-            IpAddress::v4(192, 168, 213, 3),
+            IpAddress::v4(192, 168, 213, 1),
             12345,
         )))
         .unwrap();