Initial Commit

TcpServer/Program.cs

@@ -0,0 +1,129 @@
+// See https://aka.ms/new-console-template for more information
+
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Net.Sockets;
+using System.Text;
+using System.Threading;
+
+class TcpServer
+{
+    private static TcpListener server;
+    private static bool isRunning = true;
+    private static List<TcpClient> connectedClients = new List<TcpClient>();
+
+    static void Main(string[] args)
+    {
+        server = new TcpListener(IPAddress.Any, 5000);
+        server.Start();
+        Console.WriteLine("Server started on port 5000.");
+
+        while (isRunning)
+        {
+            var client = server.AcceptTcpClient();
+            Console.WriteLine("Client connected!");
+
+            lock (connectedClients)
+            {
+                connectedClients.Add(client); // Add new client to the list
+            }
+
+            // Handle each client connection in a new thread
+            Thread clientThread = new Thread(HandleClient);
+            clientThread.Start(client);
+        }
+    }
+
+    private static void HandleClient(object obj)
+    {
+        TcpClient client = (TcpClient)obj;
+        NetworkStream stream = client.GetStream();
+        byte[] buffer = new byte[4096];
+        int bytesRead;
+
+        try
+        {
+            while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) != 0)
+            {
+                string receivedData = Encoding.ASCII.GetString(buffer, 0, bytesRead);
+                Console.WriteLine("Received: " + receivedData);
+
+                // Split the message into command and data
+                string[] messageParts = receivedData.Split(new char[] { ':' }, 2);
+                if (messageParts.Length < 2) continue; // Ignore malformed messages
+
+                string command = messageParts[0];
+                string message = messageParts[1];
+
+                switch (command)
+                {
+                    case "PUBKEY":
+                        Console.WriteLine("Received RSA Public Key: " + message);
+                        // Broadcast the message to all connected clients (excluding the sender)
+                        BroadcastMessageToClients(client, $"{command}:{message}");
+                        break;
+                    case "AESKEY":
+                        Console.WriteLine("Received Encrypted AES Key: " + message);
+                        // Broadcast the message to all connected clients (excluding the sender)
+                        BroadcastMessageToClients(client, $"{command}:{message}");
+                        break;
+                    case "MSG":
+                        Console.WriteLine("Received AES Encrypted Message: " + message);
+                        // Broadcast the message to all connected clients (excluding the sender)
+                        BroadcastMessageToClients(client, $"{command}:{message}");
+                        break;
+                    case "EXIT":
+                        Console.WriteLine("Client is disconnecting...");
+                        client.Close();
+                        lock (connectedClients)
+                        {
+                            connectedClients.Remove(client); // Remove client from the list
+                        }
+                        return;
+                    default:
+                        Console.WriteLine("Unknown command received: " + command);
+                        break;
+                }
+            }
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine("Client disconnected with error: " + ex.Message);
+        }
+        finally
+        {
+            client.Close();
+            lock (connectedClients)
+            {
+                connectedClients.Remove(client);
+            }
+            Console.WriteLine("Client disconnected.");
+        }
+    }
+
+    private static void BroadcastMessageToClients(TcpClient senderClient, string message)
+    {
+        byte[] data = Encoding.ASCII.GetBytes("Broadcast: " + message);
+
+        lock (connectedClients)
+        {
+            foreach (var client in connectedClients)
+            {
+                // Send to all clients except the sender
+                if (client != senderClient)
+                {
+                    try
+                    {
+                        NetworkStream stream = client.GetStream();
+                        stream.Write(data, 0, data.Length);
+                    }
+                    catch (Exception ex)
+                    {
+                        Console.WriteLine("Error sending to client: " + ex.Message);
+                    }
+                }
+            }
+        }
+    }
+}