From 61017aee734cb0d1a37d05509f9bc7b148db9907 Mon Sep 17 00:00:00 2001
From: 3013050 <3013050@stud.hs-mannheim.de>
Date: Wed, 15 Oct 2025 20:08:58 +0200
Subject: [PATCH] Added first discovery implementation and test client

---
 vs.pu01/vs.pu01/src/main/java/vs/Client.java | 32 ++++++++++++++++++++
 vs.pu01/vs.pu01/src/main/java/vs/Server.java | 28 ++++++++++++-----
 2 files changed, 52 insertions(+), 8 deletions(-)
 create mode 100644 vs.pu01/vs.pu01/src/main/java/vs/Client.java

diff --git a/vs.pu01/vs.pu01/src/main/java/vs/Client.java b/vs.pu01/vs.pu01/src/main/java/vs/Client.java
new file mode 100644
index 0000000..93df9e8
--- /dev/null
+++ b/vs.pu01/vs.pu01/src/main/java/vs/Client.java
@@ -0,0 +1,32 @@
+package vs;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+
+public class Client {
+    public static void main(String[] args) {
+        try (DatagramSocket socket = new DatagramSocket()) {
+            socket.setBroadcast(true);
+            String message = "DISCOVER_SERVERS";
+            byte[] buffer = message.getBytes();
+
+            InetAddress broadcastAddress = InetAddress.getByName("255.255.255.255");
+            int port = 8888;
+
+            DatagramPacket packetOut = new DatagramPacket(buffer, buffer.length, broadcastAddress, port);
+
+            socket.send(packetOut);
+
+            DatagramPacket packetIn = new DatagramPacket(new byte[512], 512);
+            socket.receive(packetIn);
+
+            String received = new String(packetIn.getData(), 0, packetIn.getLength());
+            System.out.println("Received: " + received + "IP: " + packetIn.getSocketAddress());
+        } 
+        catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}
diff --git a/vs.pu01/vs.pu01/src/main/java/vs/Server.java b/vs.pu01/vs.pu01/src/main/java/vs/Server.java
index a31ecad..d1d4817 100644
--- a/vs.pu01/vs.pu01/src/main/java/vs/Server.java
+++ b/vs.pu01/vs.pu01/src/main/java/vs/Server.java
@@ -12,18 +12,22 @@ public class Server {
     private static final ExecutorService executor = Executors.newFixedThreadPool(2);
 
     public interface PacketHandler {
-        void handlePacket(DatagramSocket socket, DatagramPacket packet, String serviceName);
+        void handlePacket(DatagramSocket socket, DatagramPacket packet, String serviceName) throws IOException;
     }
 
     public static void main(String[] args) {
-        startSocket(new DiscoveryHandler(), 8888, "Discovery Service");
-        startSocket(new SyslogHandler(), 8887, "Logging Service"); //? Port geraten idk
+        startSocket(new DiscoveryHandler(), 8888, "Discovery Service", 1);
+        startSocket(new SyslogHandler(), 514, "Logging Service", 2);
     }
 
-    private static void startSocket(PacketHandler handler, int port, String serviceName) {
+    private static void startSocket(PacketHandler handler, int port, String serviceName, int serviceID) {
         executor.execute(() -> {
             try (DatagramSocket socket = new DatagramSocket(port)) {
-                DatagramPacket packetIn = new DatagramPacket(new byte[BUFFSIZE], BUFFSIZE); //? Nicht sicher ob die Arguments richtig sind
+                if (serviceID == 1) {
+                    socket.setBroadcast(true);
+                }
+
+                DatagramPacket packetIn = new DatagramPacket(new byte[BUFFSIZE], BUFFSIZE); 
 
                 System.out.println(serviceName + " listening on port " + port);
 
@@ -42,15 +46,23 @@ public class Server {
 
     static class SyslogHandler implements PacketHandler {
         @Override
-        public void handlePacket(DatagramSocket socket, DatagramPacket packet, String serviceName) {
+        public void handlePacket(DatagramSocket socket, DatagramPacket packetIn, String serviceName) {
             
         }
     }
 
     static class DiscoveryHandler implements PacketHandler {
         @Override
-        public void handlePacket(DatagramSocket socket, DatagramPacket packet, String serviceName) {
-            
+        public void handlePacket(DatagramSocket socket, DatagramPacket packetIn, String serviceName) throws IOException {
+            DatagramPacket packetOut = new DatagramPacket(new byte[BUFFSIZE], BUFFSIZE);
+
+            packetOut.setSocketAddress(packetIn.getSocketAddress());
+            packetOut.setData(new byte[0]);
+            packetOut.setLength(0);
+
+            System.out.println("Found client, responding");
+
+            socket.send(packetOut);
         }
     }
 }