Add all of the homework 4 files, all of the graphs made, the README, and the tcp-variants-comparison file.

chatserver/README.md

@@ -1,8 +1,12 @@
 # Running the chatserver
-Use `python server.py` to run the server
+Use `python3 server.py` to run the server
 
 ## chatserver communication
-Use the client to communicate with the chatserver by running `python client.py`
+Use the client to communicate with the chatserver by running `python3 client.py`
 
 ## chatserver information
 Included is the server and client written in Python.
+
+## pcap information
+A demonstration of the chatserver has been captured with Wireshark in the 
+included `demo.pcap` file.

chatserver/client.py

@@ -1,7 +1,6 @@
 import socket
 import sys
 import select
-import os
 
 BUFFER_SIZE = 1024
 DEFAULT_HOST = 'localhost'
@@ -23,29 +22,6 @@ def main():
         client_socket.connect((SERVER_HOST, SERVER_PORT))
         print(f"Connected to chat server at {SERVER_HOST}:{SERVER_PORT}")
         
-        if os.name == 'nt':  # Windows-specific logic
-            import msvcrt
-            client_socket.setblocking(False)  # Set the socket to non-blocking mode
-
-            while True:
-                # Check for server messages
-                try:
-                    server_message = client_socket.recv(BUFFER_SIZE).decode('utf-8')
-                    if server_message:
-                        print(f"\n{server_message}")
-                        print("> ", end="", flush=True)
-                except BlockingIOError:
-                    pass
-
-                # Check for user input
-                if msvcrt.kbhit():
-                    client_message = input("> ")
-                    if client_message.strip() == "%!":
-                        print("Exiting chat...")
-                        break
-                    client_socket.send(client_message.encode('utf-8'))
-
-        else:  # Linux/Unix-specific logic
         while True:
             # use select to wait for either server messages or user input
             read_sockets, _, _ = select.select([client_socket, sys.stdin], [], [])
@@ -65,6 +41,8 @@ def main():
                     if client_message.strip() == "%!":
                         print("Exiting chat...")
                         return
+                    
+                    # send message to server
                     client_socket.send(client_message.encode('utf-8'))
     
     except Exception as e:

chatserver/server.py

@@ -1,419 +1,76 @@
 import socket
 import select
-import uuid
-import pickle
-import os
-import threading
-from flask import Flask, request, jsonify
-from flask_socketio import SocketIO, emit, join_room, leave_room
-from flask_cors import CORS
-from datetime import datetime  # Import for timestamps
-import markdown  # Import the markdown library
-
-# Flask app for REST API and WebSocket
-app = Flask(__name__)
-socketio = SocketIO(app, cors_allowed_origins="*")  # Allow all origins
-
-# Enable CORS for the Flask app
-CORS(app)
 
 CHATPORT = 8181
 BUFFER_SIZE = 1024
 MAX_CONNECT_QUEUE = 10
-DATA_FILE = 'server_data.pkl'
-UUID_FILE = 'uuids.pkl'
 
-# Global variables for chat server
-socket_list = []
-client_info = {}
-chat_rooms = {}
-client_states = {}
-uuid_dict = {}
-message_history = {}  # New: Store message history for each chat room
-server_socket = None
-quitFlag = True
-
-# Utility functions
-def save_data(client_info, chat_rooms, client_states):
-    serializable_client_info = {info["user_id"]: info for sock, info in client_info.items()}
-    serializable_chat_rooms = {info["user_id"]: chat_rooms[sock] for sock, info in client_info.items()}
-    serializable_client_states = {info["user_id"]: client_states[sock] for sock, info in client_info.items()}
-    with open(DATA_FILE, 'wb') as f:
-        pickle.dump((serializable_client_info, serializable_chat_rooms, serializable_client_states), f)
-
-def load_data():
-    if os.path.exists(DATA_FILE):
-        with open(DATA_FILE, 'rb') as f:
-            serializable_client_info, serializable_chat_rooms, serializable_client_states = pickle.load(f)
-            client_info = {uuid.UUID(user_id): info for user_id, info in serializable_client_info.items()}
-            chat_rooms = {uuid.UUID(user_id): room for user_id, room in serializable_chat_rooms.items()}
-            client_states = {uuid.UUID(user_id): state for user_id, state in serializable_client_states.items()}
-            return client_info, chat_rooms, client_states
-    return {}, {}, {}
-
-def save_uuids(uuid_dict):
-    with open(UUID_FILE, 'wb') as f:
-        pickle.dump(uuid_dict, f)
-
-def load_uuids():
-    if os.path.exists(UUID_FILE):
-        with open(UUID_FILE, 'rb') as f:
-            return pickle.load(f)
-    return {}
-
-def get_client_uuid(client_socket, uuid_dict):
-    client_address = client_socket.getpeername()
-    client_key = f"{client_address[0]}_{client_address[1]}"
-
-    if client_key in uuid_dict:
-        user_id = uuid_dict[client_key]
-    else:
-        user_id = str(uuid.uuid4())
-        uuid_dict[client_key] = user_id
-        save_uuids(uuid_dict)
-
-    return user_id
-
-def handle_message(username, chat_room, message):
-    """Store the message in history and broadcast it to all clients."""
-    # Add a timestamp to the message
-    timestamp = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
-
-    # Convert the message to HTML using Markdown
-    html_message = markdown.markdown(message)
-
-    # Store the message in the chat room's history
-    if chat_room not in message_history:
-        message_history[chat_room] = []
-    message_history[chat_room].append(f"[{timestamp}] {username}: {message}")
-
-    # Broadcast the message to WebSocket clients in the chat room
-    socketio.emit('message', {
-        'username': username,
-        'message': html_message,  # Send the HTML-rendered message
-        'timestamp': timestamp,
-        'chat_room': chat_room
-    }, room=chat_room)
-
-    # Broadcast the message to socket-based clients in the chat room
-    send_message = f"[{timestamp}] {username} >> {message}".encode('utf-8')
-    for client_sock in socket_list:
-        if client_sock != server_socket and chat_rooms.get(client_sock) == chat_room:
-            client_sock.send(send_message)
-
-def handle_command(username, chat_room, command, sock=None):
-    """Process commands sent by clients."""
-    if command.strip() == "%?":
-        help_message = (
-            "Help: (%?)\n"
-            "Send messages like normal. Use enter to send a message.\n"
-            "Available Commands:\n"
-            "\t%? : Show this help prompt.\n"
-            "\t%! : Exit from the Chat Server.\n"
-            "\t%* : Switch to another chatroom.\n"
-            "\t%$ : Change Username.\n"
-            "\t%@ <username> <message> : Send a direct message to a user.\n"
-        )
-        if sock:
-            sock.send(help_message.encode('utf-8'))
-        else:
-            socketio.emit('message', {'username': 'Server', 'message': help_message}, room=chat_room)
-        return
-
-    if command.strip() == "%*":
-        if sock:
-            sock.send(b"\nEnter chatroom name: \n")
-            client_states[sock] = "WAITING_FOR_NEW_CHATROOM"
-        else:
-            socketio.emit('message', {'username': 'Server', 'message': "Enter chatroom name:"}, room=chat_room)
-        return
-
-    if command.strip() == "%$":
-        if sock:
-            sock.send(b"\nEnter new username: \n")
-            client_states[sock] = "WAITING_FOR_NEW_USERNAME"
-        else:
-            socketio.emit('message', {'username': 'Server', 'message': "Enter new username:"}, room=chat_room)
-        return
-
-    if command.strip().startswith("%@ "):
-        parts = command.strip().split(' ', 2)
-        if len(parts) < 3:
-            error_message = "Invalid direct message format. Use: %@ <username> <message>"
-            if sock:
-                sock.send(f"\n{error_message}\n".encode('utf-8'))
-            else:
-                socketio.emit('message', {'username': 'Server', 'message': error_message}, room=chat_room)
-        else:
-            target_username = parts[1]
-            dm_message = parts[2]
-            timestamp = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
-
-            # Check if the target is a socket-based client
-            target_sock = None
-            for s, info in client_info.items():
-                if not info.get("is_websocket") and info.get("username") == target_username:
-                    target_sock = s
-                    break
-
-            # Check if the target is a WebSocket client
-            target_websocket_sid = None
-            for sid, info in client_info.items():
-                if info.get("is_websocket") and info.get("username") == target_username:
-                    target_websocket_sid = sid
-                    break
-
-            if target_sock:
-                # Send the direct message to the socket-based client
-                sender_username = username
-                target_sock.send(f"[{timestamp}] DM from {sender_username}: {dm_message}\n".encode('utf-8'))
-                if sock:
-                    sock.send(f"[{timestamp}] Direct message sent.\n".encode('utf-8'))
-            elif target_websocket_sid:
-                # Send the direct message to the WebSocket client
-                socketio.emit('message', {
-                    'username': username,
-                    'message': dm_message,
-                    'timestamp': timestamp,
-                    'chat_room': 'Direct Message'
-                }, to=target_websocket_sid)
-                if sock:
-                    sock.send(f"[{timestamp}] Direct message sent.\n".encode('utf-8'))
-            else:
-                # Target user not found
-                error_message = "User not found."
-                if sock:
-                    sock.send(f"\n{error_message}\n".encode('utf-8'))
-                else:
-                    socketio.emit('message', {'username': 'Server', 'message': error_message}, room=chat_room)
-        return
-
-    if command.strip() == "%stop":
-        if client_info.get(sock, {}).get("is_admin"):
-            print("\nAdmin has stopped the server.")
-            global quitFlag
-            quitFlag = False
-            if sock:
-                sock.send(b"\nServer is stopping...\n")
-            else:
-                socketio.emit('message', {'username': 'Server', 'message': "Server is stopping..."}, room=chat_room)
-        else:
-            error_message = "You do not have permission to stop the server."
-            if sock:
-                sock.send(f"\n{error_message}\n".encode('utf-8'))
-            else:
-                socketio.emit('message', {'username': 'Server', 'message': error_message}, room=chat_room)
-        return
-
-# REST API Endpoints
-@app.route('/send_message', methods=['POST'])
-def send_message():
-    """Send a message to a specific chat room."""
-    data = request.json
-    username = data.get('username')
-    chat_room = data.get('chat_room', 'default')
-    message = data.get('message')
-
-    if not username or not message:
-        return jsonify({"error": "Username and message are required"}), 400
-
-    if message.strip().startswith("%"):
-        handle_command(username, chat_room, message)
-    else:
-        handle_message(username, chat_room, message)
-
-    return jsonify({"status": "Message sent and processed"}), 200
-
-@app.route('/create_chatroom', methods=['POST'])
-def create_chatroom():
-    """Create a new chat room."""
-    data = request.json
-    chat_room = data.get('chat_room')
-
-    if not chat_room:
-        return jsonify({"error": "Chat room name is required"}), 400
-
-    # Add logic to create a chat room (if needed)
-    return jsonify({"status": f"Chat room '{chat_room}' created"}), 200
-
-@app.route('/get_messages', methods=['GET'])
-def get_messages():
-    """Retrieve messages for a specific user (not implemented here)."""
-    # You can implement a message queue or buffer for each user to store messages
-    return jsonify({"error": "Not implemented"}), 501
-
-@app.route('/get_history', methods=['GET'])
-def get_history():
-    """Retrieve message history for a specific chat room."""
-    chat_room = request.args.get('chat_room', 'default')
-    if chat_room not in message_history:
-        return jsonify({"messages": []})  # Return an empty list if no history exists
-
-    # Return the full message history with timestamps
-    return jsonify({"messages": message_history[chat_room]})
-
-@app.route('/send_direct_message', methods=['POST'])
-def send_direct_message():
-    """Send a direct message to a specific user."""
-    data = request.json
-    sender_username = data.get('sender_username')
-    target_username = data.get('target_username')
-    message = data.get('message')
-
-    if not sender_username or not target_username or not message:
-        return jsonify({"error": "Sender username, target username, and message are required"}), 400
-
-    timestamp = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
-
-    # Check if the target is a socket-based client
-    target_sock = None
-    for s, info in client_info.items():
-        if not info.get("is_websocket") and info.get("username") == target_username:
-            target_sock = s
-            break
-
-    # Check if the target is a WebSocket client
-    target_websocket_sid = None
-    for sid, info in client_info.items():
-        if info.get("is_websocket") and info.get("username") == target_username:
-            target_websocket_sid = sid
-            break
-
-    if target_sock:
-        # Send the direct message to the socket-based client
-        target_sock.send(f"[{timestamp}] DM from {sender_username}: {message}\n".encode('utf-8'))
-        return jsonify({"status": "Direct message sent to socket-based client"}), 200
-    elif target_websocket_sid:
-        # Send the direct message to the WebSocket client
-        socketio.emit('message', {
-            'username': sender_username,
-            'message': message,
-            'timestamp': timestamp,
-            'chat_room': 'Direct Message'
-        }, to=target_websocket_sid)
-        return jsonify({"status": "Direct message sent to WebSocket client"}), 200
-    else:
-        # Target user not found
-        return jsonify({"error": "Target user not found"}), 404
-
-# WebSocket event handlers
-@socketio.on('connect')
-def handle_connect():
-    print("WebSocket client connected")
-    # Assign a unique ID to the WebSocket client
-    user_id = str(uuid.uuid4())
-    client_info[request.sid] = {"user_id": user_id, "username": None, "is_websocket": True}
-    print(f"WebSocket client registered with ID: {user_id}")
-
-@socketio.on('disconnect')
-def handle_disconnect():
-    print("WebSocket client disconnected")
-
-@socketio.on('join')
-def handle_join(data):
-    print(f"Received join event: {data}")
-    username = data.get('username')
-    chat_room = data.get('chat_room', 'default')
-
-    if not username:
-        emit('error', {'message': 'Username is required'})
-        return
-
-    # Update client info for WebSocket clients
-    client_info[request.sid]["username"] = username
-    client_info[request.sid]["chat_room"] = chat_room
-
-    join_room(chat_room)
-    emit('message', {'username': 'Server', 'message': f"{username} has joined the chat room '{chat_room}'."}, room=chat_room)
-
-@socketio.on('leave')
-def handle_leave(data):
-    username = data.get('username')
-    chat_room = data.get('chat_room', 'default')
-    leave_room(chat_room)
-    emit('message', {'message': f"{username} has left the chat room '{chat_room}'."}, room=chat_room)
-
-@socketio.on('send_message')
-def handle_send_message(data):
-    print(f"Received send_message event: {data}")
-    username = data.get('username')
-    chat_room = data.get('chat_room', 'default')
-    message = data.get('message')
-
-    if not username or not message:
-        emit('error', {'message': 'Username and message are required'})
-        return
-
-    if message.strip().startswith("%"):
-        handle_command(username, chat_room, message)
-    else:
-        handle_message(username, chat_room, message)
-
-# Chat server logic
-def chat_server():
-    global quitFlag, server_socket, socket_list, client_info, chat_rooms, client_states, uuid_dict
-
-    # Create and configure the server socket
+def main():
+    # set the flag variable to true for infinite loop
+    quitFlag = True
+    # create a socket object
     server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    # set the socket options, SO_REUSEADDR allows to reuse the same port
+    # SO_KEEPALIVE enables the socket to send keepalive messages
     server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
     server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
+    # bind the socket to the address and port
     server_socket.bind(('', CHATPORT))
+    # listen for incoming connections
     server_socket.listen(MAX_CONNECT_QUEUE)
+    # set the server socket to non-blocking
     server_socket.setblocking(False)
 
-    socket_list.append(server_socket)
-    print(f"Chat server listening on port {CHATPORT}")
+    # create a list to store the sockets, server and client
+    socket_list = [server_socket]
+    # since a socket is associated with a username and a chatroom, 
+    # and each one can only be associated one way at once, use dictionaries to
+    # associate with each other.
+    usernames = {}
+    chat_rooms = {}
+    # keep track of the states of each client connected, and if they are 
+    # technically in an 'unsafe' state like in change username or chatroom mode.
+    client_states = {}
+    # let the user know the server is listening on port CHATPORT.
+    print(f"Chatserver listening on port: {CHATPORT}")
 
+    # infinite loop for the program
     while quitFlag:
+        # use the select function to monitor the sockets
         read_sockets, _, _ = select.select(socket_list, [], [])
+        # loop through the sockets
         for sock in read_sockets:
+            # if the socket is the server socket, accept the connection
             if sock == server_socket:
-                # Accept new client connections
                 client_socket, client_address = server_socket.accept()
                 client_socket.setblocking(False)
                 socket_list.append(client_socket)
-                print(f"Accepted connection from {client_address}")
-                client_socket.send(b"Welcome to the chat server!\n")
-                client_socket.send(b"Type in a username: \n")
+                print("\nAccepted connection from new client.")
+                client_socket.send(b"\nWelcome to the chat server!\n")
+                client_socket.send(b"\nUse '%!' to exit, or '%?' for help.\n")
+                client_socket.send(b"\nType in a username: ")
                 client_states[client_socket] = "WAITING_FOR_USERNAME"
-                user_id = get_client_uuid(client_socket, uuid_dict)
-                client_info[client_socket] = {"user_id": user_id}
+            # otherwise the socket is a client socket.
             else:
-                # Handle client messages
+                # try to receive the message from the client
                 try:
                     message = sock.recv(BUFFER_SIZE).decode('utf-8')
                     if message:
                         state = client_states.get(sock, "NORMAL")
                         if state == "WAITING_FOR_USERNAME":
-                            username = message.strip()
-                            if username == "admin":
-                                sock.send(b"\nEnter admin password: \n")
-                                client_states[sock] = "WAITING_FOR_ADMIN_PASSWORD"
-                                client_info[sock]["username"] = username
-                            else:
-                                client_info[sock]["username"] = username
+                            usernames[sock] = message.strip()
                             chat_rooms[sock] = "default"
-                                sock.send(b"\nUsername accepted. You are now in the 'default' chatroom.\n")
+                            sock.send(b"\nUsername accepted. You are now in the 'default' chatroom.")
                             client_states[sock] = "NORMAL"
-                        elif state == "WAITING_FOR_ADMIN_PASSWORD":
-                            password = message.strip()
-                            if password == "adminpass":
-                                sock.send(b"\nAdmin authenticated successfully.\n")
-                                client_info[sock]["is_admin"] = True
-                                chat_rooms[sock] = "default"
-                                client_states[sock] = "NORMAL"
-                            else:
-                                sock.send(b"\nInvalid admin password. Please enter a username: \n")
-                                client_states[sock] = "WAITING_FOR_USERNAME"
                         elif state == "WAITING_FOR_NEW_USERNAME":
-                            client_info[sock]["username"] = message.strip()
-                            sock.send(b"\nUsername changed successfully.\n")
-                            print(f"\nClient switched username to {client_info[sock]['username']}.")
+                            usernames[sock] = message.strip()
+                            sock.send(b"\nUsername changed successfully.")
+                            print(f"\nClient switched username to {usernames[sock]}.")
                             client_states[sock] = "NORMAL"
                         elif state == "WAITING_FOR_NEW_CHATROOM":
                             old_chatroom = chat_rooms[sock]
                             chat_rooms[sock] = message.strip()
-                            sock.send(f"\nSwitched to chatroom '{chat_rooms[sock]}.'\n".encode('utf-8'))
+                            sock.send(f"\nSwitched to chatroom '{chat_rooms[sock]}.'".encode('utf-8'))
                             print(f"\nClient switched to chatroom '{chat_rooms[sock]}.'")
                             if old_chatroom != "default" and old_chatroom not in chat_rooms.values():
                                 print(f"\nChatroom '{old_chatroom}' is empty and removed.")
@@ -422,22 +79,37 @@ def chat_server():
                             if message.strip() == "%!":
                                 sock.close()
                                 socket_list.remove(sock)
-                                del client_info[sock]
+                                del usernames[sock]
                                 del chat_rooms[sock]
                                 del client_states[sock]
                                 print("\nClient has closed connection.")
+                            elif message.strip() == "%?":
+                                print("\nClient requested help.")
+                                sock.send(b"Help: (%?)\n")
+                                sock.send(b"Send messages like normal. Use enter to send a message.\n")
+                                sock.send(b"Available Commands:\n")
+                                sock.send(b"\t%? : Show this help prompt.\n")
+                                sock.send(b"\t%! : Exit from the Chat Server.\n")
+                                sock.send(b"\t%* : Switch to another chatroom.\n")
+                                sock.send(b"\t%$ : Change Username.\n")
+                            elif message.strip() == "%*":
+                                sock.send(b"\nEnter chatroom name: ")
+                                client_states[sock] = "WAITING_FOR_NEW_CHATROOM"
+                            elif message.strip() == "%$":
+                                sock.send(b"\nEnter new username: ")
+                                client_states[sock] = "WAITING_FOR_NEW_USERNAME"
                             else:
-                                if message.strip().startswith("%"):
-                                    handle_command(client_info[sock]["username"], chat_rooms[sock], message, sock)
-                                else:
-                                    username = client_info[sock]["username"]
+                                username = usernames[sock]
                                 chat_room = chat_rooms[sock]
-                                    handle_message(username, chat_room, message)
+                                send_message = f"{username} >> {message}".encode('utf-8')
+                                for client_sock in socket_list:
+                                    if client_sock != server_socket and chat_rooms.get(client_sock) == chat_room:
+                                        client_sock.send(send_message)
                     else:
                         sock.close()
                         socket_list.remove(sock)
-                        if sock in client_info:
-                            del client_info[sock]
+                        if sock in usernames:
+                            del usernames[sock]
                         if sock in chat_rooms:
                             old_chatroom = chat_rooms[sock]
                             del chat_rooms[sock]
@@ -450,8 +122,8 @@ def chat_server():
                     print(f"Error: {err}")
                     sock.close()
                     socket_list.remove(sock)
-                    if sock in client_info:
-                        del client_info[sock]
+                    if sock in usernames:
+                        del usernames[sock]
                     if sock in chat_rooms:
                         old_chatroom = chat_rooms[sock]
                         del chat_rooms[sock]
@@ -461,14 +133,7 @@ def chat_server():
                         del client_states[sock]
                     print("\nClient has closed connection.")
 
-    # Save data before shutting down
-    save_data(client_info, chat_rooms, client_states)
     server_socket.close()
 
 if __name__ == "__main__":
-    # Start the chat server in a separate thread
-    server_thread = threading.Thread(target=chat_server, daemon=True)
-    server_thread.start()
-
-    # Start the Flask REST API and WebSocket server
-    socketio.run(app, host='0.0.0.0', port=5000)
+    main()

chatserver/templates/index.html

@@ -1,376 +0,0 @@
-<!DOCTYPE html>
-<html lang="en">
-<head>
-    <meta charset="UTF-8">
-    <meta name="viewport" content="width=device-width, initial-scale=1.0">
-    <title>Web Chat Client</title>
-    <script src="https://cdn.socket.io/4.5.0/socket.io.min.js"></script>
-    <script src="https://cdn.jsdelivr.net/npm/marked/marked.min.js"></script>
-    <script src="https://cdn.jsdelivr.net/npm/dompurify/dist/purify.min.js"></script>
-    <style>
-        /* Light Mode Styles */
-        body.light-mode {
-            font-family: Arial, sans-serif;
-            margin: 0;
-            padding: 0;
-            display: flex;
-            flex-direction: column;
-            height: 100vh;
-            background-color: white;
-            color: black;
-        }
-        body.light-mode #topBar {
-            background-color: #007bff;
-            color: white;
-        }
-        body.light-mode #topBar button {
-            background-color: white;
-            color: #007bff;
-        }
-        body.light-mode #topBar button:hover {
-            background-color: #e6e6e6;
-        }
-        body.light-mode #chat {
-            background-color: #f9f9f9;
-        }
-        body.light-mode #messageInput button {
-            background-color: #007bff;
-            color: white;
-        }
-        body.light-mode #messageInput button:hover {
-            background-color: #0056b3;
-        }
-
-        /* Dark Mode Styles */
-        body.dark-mode {
-            font-family: Arial, sans-serif;
-            margin: 0;
-            padding: 0;
-            display: flex;
-            flex-direction: column;
-            height: 100vh;
-            background-color: #121212;
-            color: white;
-        }
-        body.dark-mode #topBar {
-            background-color: #1e1e1e;
-            color: white;
-        }
-        body.dark-mode #topBar button {
-            background-color: #333;
-            color: white;
-        }
-        body.dark-mode #topBar button:hover {
-            background-color: #555;
-        }
-        body.dark-mode #chat {
-            background-color: #1e1e1e;
-        }
-        body.dark-mode #messageInput button {
-            background-color: #333;
-            color: white;
-        }
-        body.dark-mode #messageInput button:hover {
-            background-color: #555;
-        }
-
-        /* Shared Styles */
-        #topBar {
-            display: flex;
-            justify-content: space-between;
-            align-items: center;
-            padding: 10px;
-        }
-        #topBar span {
-            font-size: 16px;
-        }
-        #chat {
-            flex: 1;
-            overflow-y: auto;
-            padding: 10px;
-            border-bottom: 1px solid #ccc;
-        }
-        #messageInput {
-            display: flex;
-            padding: 10px;
-        }
-        #messageInput input {
-            flex: 1;
-            padding: 10px;
-            font-size: 16px;
-        }
-        #messageInput button {
-            padding: 10px;
-            font-size: 16px;
-            border: none;
-            cursor: pointer;
-            border-radius: 5px;
-        }
-    </style>
-</head>
-<body class="dark-mode">
-    <!-- Top Bar -->
-    <div id="topBar">
-        <span id="userInfo">Username: <strong id="currentUsername"></strong> | Chat Room: <strong id="currentChatRoom"></strong> | Server: <strong id="currentServer"></strong></span>
-        <div>
-            <button onclick="changeUsername()">Change Username</button>
-            <button onclick="changeChatRoom()">Change Chat Room</button>
-            <button onclick="toggleTheme()">Toggle Theme</button>
-            <button onclick="disconnectServer()">Disconnect</button>
-            <button onclick="changeServer()">Change Server</button>
-        </div>
-    </div>
-
-    <!-- Chat Messages -->
-    <div id="chat"></div>
-
-    <!-- Message Input -->
-    <div id="messageInput">
-        <input type="text" id="message" placeholder="Type a message..." onkeydown="handleKeyPress(event)">
-        <button onclick="sendMessage()">Send</button>
-    </div>
-
-    <script>
-        // Determine the default server URL based on the web client's host
-        const defaultServerUrl = `${window.location.protocol}//${window.location.hostname}:5000`;
-
-        // Ask the user for the server URL, defaulting to the web client's host
-        let serverUrl = prompt(`Enter the WebSocket server URL (default: ${defaultServerUrl}):`) || defaultServerUrl;
-
-        // Connect to the WebSocket server
-        const socket = io(serverUrl);
-
-        const chatDiv = document.getElementById('chat');
-        const messageInput = document.getElementById('message');
-        const currentUsernameElement = document.getElementById('currentUsername');
-        const currentChatRoomElement = document.getElementById('currentChatRoom');
-        const currentServerElement = document.getElementById('currentServer');
-
-        // Set the initial server URL in the top bar
-        currentServerElement.textContent = serverUrl;
-
-        // Ask the user for their username and chat room
-        let username = prompt("Enter your username:") || "Anonymous";
-        let chatRoom = prompt("Enter chat room (default: 'default')") || "default";
-
-        // Update the top bar with the current username and chat room
-        currentUsernameElement.textContent = username;
-        currentChatRoomElement.textContent = chatRoom;
-
-        // Join the chat room
-        console.log('Joining chat room:', { username: username, chat_room: chatRoom });
-        socket.emit('join', { username: username, chat_room: chatRoom });
-
-        // Fetch message history for the initial chat room
-        const serverBaseUrl = `${window.location.protocol}//${window.location.hostname}:5000`;
-        fetch(`${serverBaseUrl}/get_history?chat_room=${encodeURIComponent(chatRoom)}`)
-            .then(response => {
-                if (!response.ok) {
-                    throw new Error(`HTTP error! status: ${response.status}`);
-                }
-                return response.json();
-            })
-            .then(data => {
-                if (data.messages && data.messages.length > 0) {
-                    // Display each message in the chat history
-                    data.messages.forEach(message => {
-                        const messageElement = document.createElement('div');
-                        messageElement.textContent = message;
-                        chatDiv.appendChild(messageElement);
-                    });
-                    chatDiv.scrollTop = chatDiv.scrollHeight; // Auto-scroll to the bottom
-                } else {
-                    console.log("No message history found for this chat room.");
-                }
-            })
-            .catch(error => {
-                console.error("Error fetching message history:", error);
-            });
-
-        // Log connection status
-        socket.on('connect', () => {
-            console.log('Connected to WebSocket server');
-        });
-
-        socket.on('disconnect', () => {
-            console.log('Disconnected from WebSocket server');
-        });
-
-        // Listen for messages from the server
-        socket.on('message', (data) => {
-            const messageElement = document.createElement('div');
-
-            // Create a span for the metadata (timestamp, username, chat room)
-            const metadataSpan = document.createElement('span');
-            const timestamp = data.timestamp ? `[${data.timestamp}]` : '';
-            const chatRoomInfo = data.chat_room ? `(${data.chat_room})` : '';
-            metadataSpan.textContent = `${timestamp} ${data.username || 'Server'} ${chatRoomInfo}: `;
-            metadataSpan.style.fontWeight = 'bold'; // Optional: Make metadata bold
-
-            // Render the message as HTML using marked.js
-            let renderedMessage = marked.parse(data.message);
-
-            // Remove wrapping <p> tags if they exist
-            if (renderedMessage.startsWith('<p>') && renderedMessage.endsWith('</p>')) {
-                renderedMessage = renderedMessage.slice(3, -4); // Remove <p> and </p>
-            }
-
-            // Sanitize the HTML using DOMPurify
-            const sanitizedMessage = DOMPurify.sanitize(renderedMessage);
-
-            // Create a span for the message content
-            const messageContentSpan = document.createElement('span');
-            messageContentSpan.innerHTML = sanitizedMessage;
-
-            // Append the metadata and message content to the message element
-            messageElement.appendChild(metadataSpan);
-            messageElement.appendChild(messageContentSpan);
-
-            // Append the message element to the chat div
-            chatDiv.appendChild(messageElement);
-            chatDiv.scrollTop = chatDiv.scrollHeight; // Auto-scroll to the bottom
-        });
-
-        // Send a message to the server
-        function sendMessage() {
-            const message = messageInput.value;
-            if (message.trim() !== '') {
-                console.log('Sending message:', { username: username, chat_room: chatRoom, message: message });
-                socket.emit('send_message', { username: username, chat_room: chatRoom, message: message });
-                messageInput.value = ''; // Clear the input field
-            }
-        }
-
-        // Handle the "Enter" key to send a message
-        function handleKeyPress(event) {
-            if (event.key === "Enter") {
-                sendMessage();
-            }
-        }
-
-        // Change the username
-        function changeUsername() {
-            const newUsername = prompt("Enter your new username:");
-            if (newUsername && newUsername.trim() !== "") {
-                username = newUsername.trim();
-                currentUsernameElement.textContent = username;
-                console.log(`Username changed to: ${username}`);
-                socket.emit('send_message', { username: 'Server', chat_room: chatRoom, message: `${username} has changed their username.` });
-            }
-        }
-
-        // Change the chat room
-        function changeChatRoom() {
-            const newChatRoom = prompt("Enter the new chat room:");
-            if (newChatRoom && newChatRoom.trim() !== "") {
-                // Leave the current chat room
-                socket.emit('leave', { username: username, chat_room: chatRoom });
-
-                // Update the chat room
-                chatRoom = newChatRoom.trim();
-                currentChatRoomElement.textContent = chatRoom;
-                console.log(`Switched to chat room: ${chatRoom}`);
-
-                // Join the new chat room
-                socket.emit('join', { username: username, chat_room: chatRoom });
-
-                // Clear the chat history in the UI
-                chatDiv.innerHTML = "";
-
-                // Fetch message history for the new chat room
-                fetch(`${serverBaseUrl}/get_history?chat_room=${encodeURIComponent(chatRoom)}`)
-                    .then(response => {
-                        if (!response.ok) {
-                            throw new Error(`HTTP error! status: ${response.status}`);
-                        }
-                        return response.json();
-                    })
-                    .then(data => {
-                        if (data.messages && data.messages.length > 0) {
-                            // Display each message in the chat history
-                            data.messages.forEach(message => {
-                                const messageElement = document.createElement('div');
-                                messageElement.textContent = message;
-                                chatDiv.appendChild(messageElement);
-                            });
-                            chatDiv.scrollTop = chatDiv.scrollHeight; // Auto-scroll to the bottom
-                        } else {
-                            console.log("No message history found for this chat room.");
-                        }
-                    })
-                    .catch(error => {
-                        console.error("Error fetching message history:", error);
-                    });
-            }
-        }
-
-        // Disconnect from the current server
-        function disconnectServer() {
-            if (socket.connected) {
-                socket.disconnect();
-                console.log("Disconnected from the server");
-                alert("You have been disconnected from the server.");
-                currentServerElement.textContent = "Disconnected"; // Update the displayed server URL
-            } else {
-                alert("You are not connected to any server.");
-            }
-        }
-
-        // Change the server to connect to
-        function changeServer() {
-            if (socket.connected) {
-                socket.disconnect();
-                console.log("Disconnected from the current server");
-            }
-
-            const newServerUrl = prompt("Enter the new WebSocket server URL (e.g., http://localhost:5000):");
-            if (newServerUrl && newServerUrl.trim() !== "") {
-                serverUrl = newServerUrl.trim();
-                console.log(`Connecting to new server: ${serverUrl}`);
-                socket.io.uri = serverUrl; // Update the server URL
-                socket.connect(); // Reconnect to the new server
-                currentServerElement.textContent = serverUrl; // Update the displayed server URL
-                alert(`Connected to the new server: ${serverUrl}`);
-            } else {
-                alert("Server URL cannot be empty.");
-            }
-        }
-
-        // Reconnect to the server
-        function reconnectServer() {
-            if (!socket.connected) {
-                console.log("Reconnecting to the server...");
-                socket.connect();
-                alert("Reconnected to the server.");
-            } else {
-                alert("You are already connected to the server.");
-            }
-        }
-
-        // Toggle between light mode and dark mode
-        function toggleTheme() {
-            const body = document.body;
-            if (body.classList.contains('light-mode')) {
-                body.classList.remove('light-mode');
-                body.classList.add('dark-mode');
-                localStorage.setItem('theme', 'dark-mode'); // Save preference
-            } else {
-                body.classList.remove('dark-mode');
-                body.classList.add('light-mode');
-                localStorage.setItem('theme', 'light-mode'); // Save preference
-            }
-        }
-
-        // Apply saved theme on page load
-        const savedTheme = localStorage.getItem('theme') || 'dark-mode'; // Default to dark mode
-        document.body.classList.add(savedTheme);
-
-        // Set options for marked.js
-        marked.setOptions({
-            breaks: false, // Disable line breaks
-            gfm: true,     // Enable GitHub Flavored Markdown
-            headerIds: false // Disable header IDs
-        });
-    </script>
-</body>
-</html>

chatserver/webclient.py

@@ -1,10 +0,0 @@
-from flask import Flask, render_template
-
-app = Flask(__name__)
-
-@app.route('/')
-def index():
-    return render_template('index.html')  # Serve the HTML client
-
-if __name__ == "__main__":
-    app.run(host='0.0.0.0', port=8080)  # Run the web client on port 8080

echoserver/Makefile

@@ -0,0 +1,20 @@
+CC = gcc -Wall -std=c11 -pedantic
+SOURCES = echoserver.c 
+OBJECTS = echoserver.o 
+
+all: echoserver
+
+echoserver: $(OBJECTS)
+	$(CC) $(OBJECTS) -o echoserver
+
+echoserver.o: echoserver.c
+	$(CC) -c echoserver.c -o echoserver.o
+
+clean:
+	rm -f $(OBJECTS) echoserver echoserver.out
+
+clean_objects:
+	rm -f $(OBJECTS)
+
+run:
+	./echoserver

echoserver/README.md

@@ -0,0 +1,10 @@
+# Running the echoserver
+Use `make` to compile the echoserver.
+Use `make run` to run the echoserver. This will run on an infinite loop.
+Use `Ctrl+C` to stop the echoserver.
+
+## echoserver communication
+Communicating with the server can happen using telnet in TCP mode.
+
+## echoserver information
+The echoserver runs on TCP port 8888.

echoserver/echoserver.c

@@ -0,0 +1,150 @@
+// header files
+#include "echoserver.h"
+
+// constants
+// echoserver port is 8888
+#define ECHOPORT 8888
+#define BUFFER_SIZE 1024
+#define MAX_CONNECT_QUEUE 10
+
+// prototypes
+
+// main function
+int main(int argc, char **argv)
+{
+    // initialize program (variables and structs)
+    bool quitFlag = true;
+    int socketEchoFD;
+    int clientEchoFD;
+    int reuseAddrOpt = 1;
+    int keepAliveOpt = 1;
+    char message[BUFFER_SIZE];
+    int messageBytes;
+    struct sockaddr_in serverAddr;
+    struct sockaddr_storage clientAddr;
+    socklen_t clientSize;
+    memset(&serverAddr, 0, sizeof(serverAddr));
+    memset(&clientAddr, 0, sizeof(clientAddr));
+    // define a TCP socket
+    socketEchoFD = socket(AF_INET, SOCK_STREAM, 0);
+    if(socketEchoFD < 0)
+    {
+        printf("Unable to create the socket.\n");
+        return -1;
+    }
+    // use the setsockopt function to make the socket accept different configurations
+    // allow for the reuse of the address/bind.
+    setsockopt(socketEchoFD, SOL_SOCKET, SO_REUSEADDR, &reuseAddrOpt, sizeof(reuseAddrOpt));
+    // also need to set the socket to keepalive using setsockopt
+    setsockopt(socketEchoFD, SOL_SOCKET, SO_KEEPALIVE, &keepAliveOpt, sizeof(keepAliveOpt));
+    // bind the TCP socket to port 8888 / ECHOPORT
+    serverAddr.sin_family = AF_INET;
+    serverAddr.sin_addr.s_addr = INADDR_ANY;
+    serverAddr.sin_port = htons(ECHOPORT);
+    int bindCheck = bind(socketEchoFD, &serverAddr, sizeof(serverAddr));
+    if(bindCheck < 0)
+    {
+        printf("Unable to bind the socket to the port or address.\n Is either in use?");
+        return -1;
+    }
+    // use fnctl to set the non-blocking flag for the socket
+    fcntl(socketEchoFD, F_SETFL, O_NONBLOCK);
+    // the server will now accept client connections by listening.
+    listen(socketEchoFD, MAX_CONNECT_QUEUE);
+    // create a file descriptor set, to keep track of the sockets in use using fd_set and FD_ZERO?
+    fd_set socketList;
+    FD_ZERO(&socketList);
+    // add the socketEchoFD to the file descriptor set using fd_set
+    FD_SET(socketEchoFD, &socketList);
+    // max file descriptor, this will be used to 'find' the socket currently connected
+    int maxFD = socketEchoFD;
+    // while loop that will continue to listen for messages from clients.
+    printf("Echoserver listening on port: %d\n", ECHOPORT);
+    while (quitFlag)
+    {
+        // set of active connections
+        fd_set activeSet = socketList;
+        // use the select() function here to check the set of sockets
+        int selectedFD = select(maxFD+1, &activeSet, NULL, NULL, NULL);
+        // check to make sure select() didn't error out.
+        if(selectedFD == -1)
+        {
+            //
+            printf("\nUnable to select socket to listen to.\n");
+            return -1;
+        }
+        // for loop that loops up to the max file descriptor.
+        for(int fileIter = 0; fileIter <= maxFD; fileIter++)
+        {
+            // check to see if the file descriptor is in the set of sockets using FD_ISSET()
+            if(FD_ISSET(fileIter, &activeSet))
+            {
+                // if the server socket is being written to/read from,
+                if(fileIter == socketEchoFD)
+                {
+                    // create a client socket using accept
+                    clientSize = sizeof(clientAddr);
+                    clientEchoFD = accept(socketEchoFD, &clientAddr, &clientSize);
+                    // check to see if the client socket is connected (-1)
+                    if(clientEchoFD == -1)
+                    {
+                        printf("\nCould not connect the client to a socket.\n");
+                        return -1;
+                    }
+                    else
+                    {
+                        // set the non blocking flag using fnctl
+                        fcntl(clientEchoFD, F_SETFL, O_NONBLOCK);
+                        // add the client socket to the set of file descriptor sockets
+                        FD_SET(clientEchoFD, &socketList);
+                        // check to see if the new socket FD is greater than the current max (clientSocket > maxFD)
+                        if(clientEchoFD > maxFD)
+                        {
+                            // if it is, set the new max.
+                            maxFD = clientEchoFD;
+                        }
+                        printf("\nConnected client to socket.\n");
+                    }
+                    printf("\nAccepted connection from new client.\n");
+                }
+                // if the client socket(s) are being written to/read from,
+                else
+                {
+                    // grab the data from the client, save to message.
+                    messageBytes = recv(fileIter, message, BUFFER_SIZE, 0);
+                    // make sure that the connection is still open before attempting to send.
+                    if(messageBytes <= 0) // old: messageBytes <= 0
+                    {
+                        // if it is not open, close the socket and remove the socket from the socket list using FD_CLR()
+                        close(fileIter);
+                        FD_CLR(fileIter, &socketList);
+                        printf("\nClient has closed connection.\n");
+                    }
+                    else
+                    {
+                        // if it is open, send the message back to the client over the client socket
+                        send(fileIter, message, messageBytes, 0);
+                        printf("\nMessage has been sent back to client.\n");
+                    }
+                }
+            }
+        }
+    }
+    // close the socket
+    close(socketEchoFD);
+    // profit???
+    return 0;
+}
+
+// function definitions
+
+/*
+Name: ???
+Process: ???
+Function Input/Parameters: ???
+Function Output/Parameters: ???
+Function Output/Returned: ???
+Device Input/Device: ???
+Device Output/Device: ???
+Dependencies: ???
+*/

echoserver/echoserver.h

@@ -0,0 +1,25 @@
+#ifndef ECHOSERVER
+#define ECHOSERVER
+
+// included libraries
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <stdbool.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/select.h>
+#include <netdb.h>
+#include <time.h>
+#include <unistd.h>
+#include <errno.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <fcntl.h>
+
+// data structures
+
+// function prototypes
+
+#endif // ECHOSERVER

networksim/README.md

@@ -0,0 +1,7 @@
+# Adapted tcp-variants-comparison file
+The `tcp-variants-comparison.cc` file has been adapted to allow for multiple TCP variants to be run in one simulation.
+In order to change the variants ran, find line 510-524. This is where the magic of which variants to run is.
+The code relies on multiple flows to also be ran, which can be found using the number of cases - 1. If you want to test the file, you'll want to replace the file with this modified version, which must then be rebuilt. You should be able to use `./ns3 build tcp-variants-comparison` (or `./ns3 build examples/tcp-variants-comparison` might work better) although this hasn't been tested, and the best method is to use ccache to cache the build before making the modification.
+
+## How to find the cwnd of multiple TCP variants (how to run)
+The command `./ns3 run tcp-variants-comparison --command-template="%s --tracing=1 --prefix_name=CS460Homework4_TCPCmp --num_flows=3 --access_delay=50ms"` can be used to find the comparisons between TCP variants. You'll want the number of flows to equal the amount of cases in the switch statement.

networksim/tcp-variants-comparison.cc

@@ -0,0 +1,624 @@
+/*
+ * Copyright (c) 2013 ResiliNets, ITTC, University of Kansas
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ * Authors: Justin P. Rohrer, Truc Anh N. Nguyen <annguyen@ittc.ku.edu>, Siddharth Gangadhar
+ * <siddharth@ittc.ku.edu>
+ *
+ * James P.G. Sterbenz <jpgs@ittc.ku.edu>, director
+ * ResiliNets Research Group  https://resilinets.org/
+ * Information and Telecommunication Technology Center (ITTC)
+ * and Department of Electrical Engineering and Computer Science
+ * The University of Kansas Lawrence, KS USA.
+ *
+ * Work supported in part by NSF FIND (Future Internet Design) Program
+ * under grant CNS-0626918 (Postmodern Internet Architecture),
+ * NSF grant CNS-1050226 (Multilayer Network Resilience Analysis and Experimentation on GENI),
+ * US Department of Defense (DoD), and ITTC at The University of Kansas.
+ *
+ * "TCP Westwood(+) Protocol Implementation in ns-3"
+ * Siddharth Gangadhar, Trúc Anh Ngọc Nguyễn , Greeshma Umapathi, and James P.G. Sterbenz,
+ * ICST SIMUTools Workshop on ns-3 (WNS3), Cannes, France, March 2013
+ */
+
+#include "ns3/applications-module.h"
+#include "ns3/core-module.h"
+#include "ns3/enum.h"
+#include "ns3/error-model.h"
+#include "ns3/event-id.h"
+#include "ns3/flow-monitor-helper.h"
+#include "ns3/internet-module.h"
+#include "ns3/ipv4-global-routing-helper.h"
+#include "ns3/network-module.h"
+#include "ns3/point-to-point-module.h"
+#include "ns3/tcp-header.h"
+#include "ns3/traffic-control-module.h"
+#include "ns3/udp-header.h"
+
+#include <fstream>
+#include <iostream>
+#include <string>
+
+using namespace ns3;
+
+NS_LOG_COMPONENT_DEFINE("TcpVariantsComparison");
+
+static std::map<uint32_t, bool> firstCwnd;                      //!< First congestion window.
+static std::map<uint32_t, bool> firstSshThr;                    //!< First SlowStart threshold.
+static std::map<uint32_t, bool> firstRtt;                       //!< First RTT.
+static std::map<uint32_t, bool> firstRto;                       //!< First RTO.
+static std::map<uint32_t, Ptr<OutputStreamWrapper>> cWndStream; //!< Congstion window output stream.
+static std::map<uint32_t, Ptr<OutputStreamWrapper>>
+    ssThreshStream; //!< SlowStart threshold output stream.
+static std::map<uint32_t, Ptr<OutputStreamWrapper>> rttStream;      //!< RTT output stream.
+static std::map<uint32_t, Ptr<OutputStreamWrapper>> rtoStream;      //!< RTO output stream.
+static std::map<uint32_t, Ptr<OutputStreamWrapper>> nextTxStream;   //!< Next TX output stream.
+static std::map<uint32_t, Ptr<OutputStreamWrapper>> nextRxStream;   //!< Next RX output stream.
+static std::map<uint32_t, Ptr<OutputStreamWrapper>> inFlightStream; //!< In flight output stream.
+static std::map<uint32_t, uint32_t> cWndValue;                      //!< congestion window value.
+static std::map<uint32_t, uint32_t> ssThreshValue;                  //!< SlowStart threshold value.
+
+/**
+ * Get the Node Id From Context.
+ *
+ * @param context The context.
+ * @return the node ID.
+ */
+static uint32_t
+GetNodeIdFromContext(std::string context)
+{
+    const std::size_t n1 = context.find_first_of('/', 1);
+    const std::size_t n2 = context.find_first_of('/', n1 + 1);
+    return std::stoul(context.substr(n1 + 1, n2 - n1 - 1));
+}
+
+/**
+ * Congestion window tracer.
+ *
+ * @param context The context.
+ * @param oldval Old value.
+ * @param newval New value.
+ */
+static void
+CwndTracer(std::string context, uint32_t oldval, uint32_t newval)
+{
+    uint32_t nodeId = GetNodeIdFromContext(context);
+
+    if (firstCwnd[nodeId])
+    {
+        *cWndStream[nodeId]->GetStream() << "0.0 " << oldval << std::endl;
+        firstCwnd[nodeId] = false;
+    }
+    *cWndStream[nodeId]->GetStream() << Simulator::Now().GetSeconds() << " " << newval << std::endl;
+    cWndValue[nodeId] = newval;
+
+    if (!firstSshThr[nodeId])
+    {
+        *ssThreshStream[nodeId]->GetStream()
+            << Simulator::Now().GetSeconds() << " " << ssThreshValue[nodeId] << std::endl;
+    }
+}
+
+/**
+ * Slow start threshold tracer.
+ *
+ * @param context The context.
+ * @param oldval Old value.
+ * @param newval New value.
+ */
+static void
+SsThreshTracer(std::string context, uint32_t oldval, uint32_t newval)
+{
+    uint32_t nodeId = GetNodeIdFromContext(context);
+
+    if (firstSshThr[nodeId])
+    {
+        *ssThreshStream[nodeId]->GetStream() << "0.0 " << oldval << std::endl;
+        firstSshThr[nodeId] = false;
+    }
+    *ssThreshStream[nodeId]->GetStream()
+        << Simulator::Now().GetSeconds() << " " << newval << std::endl;
+    ssThreshValue[nodeId] = newval;
+
+    if (!firstCwnd[nodeId])
+    {
+        *cWndStream[nodeId]->GetStream()
+            << Simulator::Now().GetSeconds() << " " << cWndValue[nodeId] << std::endl;
+    }
+}
+
+/**
+ * RTT tracer.
+ *
+ * @param context The context.
+ * @param oldval Old value.
+ * @param newval New value.
+ */
+static void
+RttTracer(std::string context, Time oldval, Time newval)
+{
+    uint32_t nodeId = GetNodeIdFromContext(context);
+
+    if (firstRtt[nodeId])
+    {
+        *rttStream[nodeId]->GetStream() << "0.0 " << oldval.GetSeconds() << std::endl;
+        firstRtt[nodeId] = false;
+    }
+    *rttStream[nodeId]->GetStream()
+        << Simulator::Now().GetSeconds() << " " << newval.GetSeconds() << std::endl;
+}
+
+/**
+ * RTO tracer.
+ *
+ * @param context The context.
+ * @param oldval Old value.
+ * @param newval New value.
+ */
+static void
+RtoTracer(std::string context, Time oldval, Time newval)
+{
+    uint32_t nodeId = GetNodeIdFromContext(context);
+
+    if (firstRto[nodeId])
+    {
+        *rtoStream[nodeId]->GetStream() << "0.0 " << oldval.GetSeconds() << std::endl;
+        firstRto[nodeId] = false;
+    }
+    *rtoStream[nodeId]->GetStream()
+        << Simulator::Now().GetSeconds() << " " << newval.GetSeconds() << std::endl;
+}
+
+/**
+ * Next TX tracer.
+ *
+ * @param context The context.
+ * @param old Old sequence number.
+ * @param nextTx Next sequence number.
+ */
+static void
+NextTxTracer(std::string context, SequenceNumber32 old [[maybe_unused]], SequenceNumber32 nextTx)
+{
+    uint32_t nodeId = GetNodeIdFromContext(context);
+
+    *nextTxStream[nodeId]->GetStream()
+        << Simulator::Now().GetSeconds() << " " << nextTx << std::endl;
+}
+
+/**
+ * In-flight tracer.
+ *
+ * @param context The context.
+ * @param old Old value.
+ * @param inFlight In flight value.
+ */
+static void
+InFlightTracer(std::string context, uint32_t old [[maybe_unused]], uint32_t inFlight)
+{
+    uint32_t nodeId = GetNodeIdFromContext(context);
+
+    *inFlightStream[nodeId]->GetStream()
+        << Simulator::Now().GetSeconds() << " " << inFlight << std::endl;
+}
+
+/**
+ * Next RX tracer.
+ *
+ * @param context The context.
+ * @param old Old sequence number.
+ * @param nextRx Next sequence number.
+ */
+static void
+NextRxTracer(std::string context, SequenceNumber32 old [[maybe_unused]], SequenceNumber32 nextRx)
+{
+    uint32_t nodeId = GetNodeIdFromContext(context);
+
+    *nextRxStream[nodeId]->GetStream()
+        << Simulator::Now().GetSeconds() << " " << nextRx << std::endl;
+}
+
+/**
+ * Congestion window trace connection.
+ *
+ * @param cwnd_tr_file_name Congestion window trace file name.
+ * @param nodeId Node ID.
+ */
+static void
+TraceCwnd(std::string cwnd_tr_file_name, uint32_t nodeId)
+{
+    AsciiTraceHelper ascii;
+    cWndStream[nodeId] = ascii.CreateFileStream(cwnd_tr_file_name);
+    Config::Connect("/NodeList/" + std::to_string(nodeId) +
+                        "/$ns3::TcpL4Protocol/SocketList/0/CongestionWindow",
+                    MakeCallback(&CwndTracer));
+}
+
+/**
+ * Slow start threshold trace connection.
+ *
+ * @param ssthresh_tr_file_name Slow start threshold trace file name.
+ * @param nodeId Node ID.
+ */
+static void
+TraceSsThresh(std::string ssthresh_tr_file_name, uint32_t nodeId)
+{
+    AsciiTraceHelper ascii;
+    ssThreshStream[nodeId] = ascii.CreateFileStream(ssthresh_tr_file_name);
+    Config::Connect("/NodeList/" + std::to_string(nodeId) +
+                        "/$ns3::TcpL4Protocol/SocketList/0/SlowStartThreshold",
+                    MakeCallback(&SsThreshTracer));
+}
+
+/**
+ * RTT trace connection.
+ *
+ * @param rtt_tr_file_name RTT trace file name.
+ * @param nodeId Node ID.
+ */
+static void
+TraceRtt(std::string rtt_tr_file_name, uint32_t nodeId)
+{
+    AsciiTraceHelper ascii;
+    rttStream[nodeId] = ascii.CreateFileStream(rtt_tr_file_name);
+    Config::Connect("/NodeList/" + std::to_string(nodeId) + "/$ns3::TcpL4Protocol/SocketList/0/RTT",
+                    MakeCallback(&RttTracer));
+}
+
+/**
+ * RTO trace connection.
+ *
+ * @param rto_tr_file_name RTO trace file name.
+ * @param nodeId Node ID.
+ */
+static void
+TraceRto(std::string rto_tr_file_name, uint32_t nodeId)
+{
+    AsciiTraceHelper ascii;
+    rtoStream[nodeId] = ascii.CreateFileStream(rto_tr_file_name);
+    Config::Connect("/NodeList/" + std::to_string(nodeId) + "/$ns3::TcpL4Protocol/SocketList/0/RTO",
+                    MakeCallback(&RtoTracer));
+}
+
+/**
+ * Next TX trace connection.
+ *
+ * @param next_tx_seq_file_name Next TX trace file name.
+ * @param nodeId Node ID.
+ */
+static void
+TraceNextTx(std::string& next_tx_seq_file_name, uint32_t nodeId)
+{
+    AsciiTraceHelper ascii;
+    nextTxStream[nodeId] = ascii.CreateFileStream(next_tx_seq_file_name);
+    Config::Connect("/NodeList/" + std::to_string(nodeId) +
+                        "/$ns3::TcpL4Protocol/SocketList/0/NextTxSequence",
+                    MakeCallback(&NextTxTracer));
+}
+
+/**
+ * In flight trace connection.
+ *
+ * @param in_flight_file_name In flight trace file name.
+ * @param nodeId Node ID.
+ */
+static void
+TraceInFlight(std::string& in_flight_file_name, uint32_t nodeId)
+{
+    AsciiTraceHelper ascii;
+    inFlightStream[nodeId] = ascii.CreateFileStream(in_flight_file_name);
+    Config::Connect("/NodeList/" + std::to_string(nodeId) +
+                        "/$ns3::TcpL4Protocol/SocketList/0/BytesInFlight",
+                    MakeCallback(&InFlightTracer));
+}
+
+/**
+ * Next RX trace connection.
+ *
+ * @param next_rx_seq_file_name Next RX trace file name.
+ * @param nodeId Node ID.
+ */
+static void
+TraceNextRx(std::string& next_rx_seq_file_name, uint32_t nodeId)
+{
+    AsciiTraceHelper ascii;
+    nextRxStream[nodeId] = ascii.CreateFileStream(next_rx_seq_file_name);
+    Config::Connect("/NodeList/" + std::to_string(nodeId) +
+                        "/$ns3::TcpL4Protocol/SocketList/1/RxBuffer/NextRxSequence",
+                    MakeCallback(&NextRxTracer));
+}
+
+int
+main(int argc, char* argv[])
+{
+    std::string transport_prot = "TcpWestwoodPlus";
+    double error_p = 0.0;
+    std::string bandwidth = "2Mbps";
+    std::string delay = "0.01ms";
+    std::string access_bandwidth = "10Mbps";
+    std::string access_delay = "45ms";
+    bool tracing = false;
+    std::string prefix_file_name = "TcpVariantsComparison";
+    uint64_t data_mbytes = 0;
+    uint32_t mtu_bytes = 400;
+    uint16_t num_flows = 1;
+    double duration = 100.0;
+    uint32_t run = 0;
+    bool flow_monitor = false;
+    bool pcap = false;
+    bool sack = true;
+    std::string queue_disc_type = "ns3::PfifoFastQueueDisc";
+    std::string recovery = "ns3::TcpClassicRecovery";
+
+    CommandLine cmd(__FILE__);
+    cmd.AddValue("transport_prot",
+                 "Transport protocol to use: TcpNewReno, TcpLinuxReno, "
+                 "TcpHybla, TcpHighSpeed, TcpHtcp, TcpVegas, TcpScalable, TcpVeno, "
+                 "TcpBic, TcpYeah, TcpIllinois, TcpWestwoodPlus, TcpLedbat, "
+                 "TcpLp, TcpDctcp, TcpCubic, TcpBbr",
+                 transport_prot);
+    cmd.AddValue("error_p", "Packet error rate", error_p);
+    cmd.AddValue("bandwidth", "Bottleneck bandwidth", bandwidth);
+    cmd.AddValue("delay", "Bottleneck delay", delay);
+    cmd.AddValue("access_bandwidth", "Access link bandwidth", access_bandwidth);
+    cmd.AddValue("access_delay", "Access link delay", access_delay);
+    cmd.AddValue("tracing", "Flag to enable/disable tracing", tracing);
+    cmd.AddValue("prefix_name", "Prefix of output trace file", prefix_file_name);
+    cmd.AddValue("data", "Number of Megabytes of data to transmit", data_mbytes);
+    cmd.AddValue("mtu", "Size of IP packets to send in bytes", mtu_bytes);
+    cmd.AddValue("num_flows", "Number of flows", num_flows);
+    cmd.AddValue("duration", "Time to allow flows to run in seconds", duration);
+    cmd.AddValue("run", "Run index (for setting repeatable seeds)", run);
+    cmd.AddValue("flow_monitor", "Enable flow monitor", flow_monitor);
+    cmd.AddValue("pcap_tracing", "Enable or disable PCAP tracing", pcap);
+    cmd.AddValue("queue_disc_type",
+                 "Queue disc type for gateway (e.g. ns3::CoDelQueueDisc)",
+                 queue_disc_type);
+    cmd.AddValue("sack", "Enable or disable SACK option", sack);
+    cmd.AddValue("recovery", "Recovery algorithm type to use (e.g., ns3::TcpPrrRecovery", recovery);
+    cmd.Parse(argc, argv);
+
+    transport_prot = std::string("ns3::") + transport_prot;
+
+    SeedManager::SetSeed(1);
+    SeedManager::SetRun(run);
+
+    // User may find it convenient to enable logging
+    // LogComponentEnable("TcpVariantsComparison", LOG_LEVEL_ALL);
+    // LogComponentEnable("BulkSendApplication", LOG_LEVEL_INFO);
+    // LogComponentEnable("PfifoFastQueueDisc", LOG_LEVEL_ALL);
+
+    // Calculate the ADU size
+    Header* temp_header = new Ipv4Header();
+    uint32_t ip_header = temp_header->GetSerializedSize();
+    NS_LOG_LOGIC("IP Header size is: " << ip_header);
+    delete temp_header;
+    temp_header = new TcpHeader();
+    uint32_t tcp_header = temp_header->GetSerializedSize();
+    NS_LOG_LOGIC("TCP Header size is: " << tcp_header);
+    delete temp_header;
+    uint32_t tcp_adu_size = mtu_bytes - 20 - (ip_header + tcp_header);
+    NS_LOG_LOGIC("TCP ADU size is: " << tcp_adu_size);
+
+    // Set the simulation start and stop time
+    double start_time = 0.1;
+    double stop_time = start_time + duration;
+
+    // 2 MB of TCP buffer
+    Config::SetDefault("ns3::TcpSocket::RcvBufSize", UintegerValue(1 << 21));
+    Config::SetDefault("ns3::TcpSocket::SndBufSize", UintegerValue(1 << 21));
+    Config::SetDefault("ns3::TcpSocketBase::Sack", BooleanValue(sack));
+
+    Config::SetDefault("ns3::TcpL4Protocol::RecoveryType",
+                       TypeIdValue(TypeId::LookupByName(recovery)));
+    // Select TCP variant
+    TypeId tcpTid;
+    NS_ABORT_MSG_UNLESS(TypeId::LookupByNameFailSafe(transport_prot, &tcpTid),
+                        "TypeId " << transport_prot << " not found");
+    Config::SetDefault("ns3::TcpL4Protocol::SocketType",
+                       TypeIdValue(TypeId::LookupByName(transport_prot)));
+
+    // Create gateways, sources, and sinks
+    NodeContainer gateways;
+    gateways.Create(1);
+    NodeContainer sources;
+    sources.Create(num_flows);
+    NodeContainer sinks;
+    sinks.Create(num_flows);
+
+    // Configure the error model
+    // Here we use RateErrorModel with packet error rate
+    Ptr<UniformRandomVariable> uv = CreateObject<UniformRandomVariable>();
+    uv->SetStream(50);
+    RateErrorModel error_model;
+    error_model.SetRandomVariable(uv);
+    error_model.SetUnit(RateErrorModel::ERROR_UNIT_PACKET);
+    error_model.SetRate(error_p);
+
+    PointToPointHelper UnReLink;
+    UnReLink.SetDeviceAttribute("DataRate", StringValue(bandwidth));
+    UnReLink.SetChannelAttribute("Delay", StringValue(delay));
+    UnReLink.SetDeviceAttribute("ReceiveErrorModel", PointerValue(&error_model));
+
+    InternetStackHelper stack;
+    stack.InstallAll();
+
+    TrafficControlHelper tchPfifo;
+    tchPfifo.SetRootQueueDisc("ns3::PfifoFastQueueDisc");
+
+    TrafficControlHelper tchCoDel;
+    tchCoDel.SetRootQueueDisc("ns3::CoDelQueueDisc");
+
+    Ipv4AddressHelper address;
+    address.SetBase("10.0.0.0", "255.255.255.0");
+
+    // Configure the sources and sinks net devices
+    // and the channels between the sources/sinks and the gateways
+    PointToPointHelper LocalLink;
+    LocalLink.SetDeviceAttribute("DataRate", StringValue(access_bandwidth));
+    LocalLink.SetChannelAttribute("Delay", StringValue(access_delay));
+
+    Ipv4InterfaceContainer sink_interfaces;
+
+    DataRate access_b(access_bandwidth);
+    DataRate bottle_b(bandwidth);
+    Time access_d(access_delay);
+    Time bottle_d(delay);
+
+    uint32_t size = static_cast<uint32_t>((std::min(access_b, bottle_b).GetBitRate() / 8) *
+                                          ((access_d + bottle_d) * 2).GetSeconds());
+
+    Config::SetDefault("ns3::PfifoFastQueueDisc::MaxSize",
+                       QueueSizeValue(QueueSize(QueueSizeUnit::PACKETS, size / mtu_bytes)));
+    Config::SetDefault("ns3::CoDelQueueDisc::MaxSize",
+                       QueueSizeValue(QueueSize(QueueSizeUnit::BYTES, size)));
+
+    for (uint32_t i = 0; i < num_flows; i++)
+    {
+        NetDeviceContainer devices;
+        devices = LocalLink.Install(sources.Get(i), gateways.Get(0));
+        tchPfifo.Install(devices);
+        address.NewNetwork();
+        Ipv4InterfaceContainer interfaces = address.Assign(devices);
+
+        devices = UnReLink.Install(gateways.Get(0), sinks.Get(i));
+        if (queue_disc_type == "ns3::PfifoFastQueueDisc")
+        {
+            tchPfifo.Install(devices);
+        }
+        else if (queue_disc_type == "ns3::CoDelQueueDisc")
+        {
+            tchCoDel.Install(devices);
+        }
+        else
+        {
+            NS_FATAL_ERROR("Queue not recognized. Allowed values are ns3::CoDelQueueDisc or "
+                           "ns3::PfifoFastQueueDisc");
+        }
+        address.NewNetwork();
+        interfaces = address.Assign(devices);
+        sink_interfaces.Add(interfaces.Get(1));
+    }
+
+    NS_LOG_INFO("Initialize Global Routing.");
+    Ipv4GlobalRoutingHelper::PopulateRoutingTables();
+
+    uint16_t port = 50000;
+    Address sinkLocalAddress(InetSocketAddress(Ipv4Address::GetAny(), port));
+    PacketSinkHelper sinkHelper("ns3::TcpSocketFactory", sinkLocalAddress);
+
+    for (uint32_t i = 0; i < sources.GetN(); i++)
+    {
+        // Assign a different TCP variant to each flow
+        std::string tcpVariant;
+        switch (i % 2) // Example: Rotate between two TCP variants
+        {
+        case 0:
+            tcpVariant = "ns3::TcpNewReno";
+            break;
+        case 1:
+            tcpVariant = "ns3::TcpCubic";
+            break;
+        default:
+            tcpVariant = "ns3::TcpNewReno";
+        }
+
+        // Set the TCP variant for this flow
+        Config::Set("/NodeList/" + std::to_string(sources.Get(i)->GetId()) +
+                        "/$ns3::TcpL4Protocol/SocketType",
+                    StringValue(tcpVariant));
+
+        // Configure the BulkSend application
+        Address remoteAddress(InetSocketAddress(sink_interfaces.GetAddress(i, 0), port));
+        BulkSendHelper ftp("ns3::TcpSocketFactory", remoteAddress);
+        ftp.SetAttribute("SendSize", UintegerValue(tcp_adu_size));
+        ftp.SetAttribute("MaxBytes", UintegerValue(data_mbytes * 1000000));
+
+        ApplicationContainer sourceApp = ftp.Install(sources.Get(i));
+        sourceApp.Start(Seconds(start_time * i));
+        sourceApp.Stop(Seconds(stop_time - 3));
+
+        // Configure the PacketSink application
+        sinkHelper.SetAttribute("Protocol", TypeIdValue(TcpSocketFactory::GetTypeId()));
+        ApplicationContainer sinkApp = sinkHelper.Install(sinks.Get(i));
+        sinkApp.Start(Seconds(start_time * i));
+        sinkApp.Stop(Seconds(stop_time));
+    }
+
+    // Set up tracing if enabled
+    if (tracing)
+    {
+        std::ofstream ascii;
+        Ptr<OutputStreamWrapper> ascii_wrap;
+        ascii.open(prefix_file_name + "-ascii");
+        ascii_wrap = new OutputStreamWrapper(prefix_file_name + "-ascii", std::ios::out);
+        stack.EnableAsciiIpv4All(ascii_wrap);
+
+        for (uint16_t index = 0; index < num_flows; index++)
+        {
+            std::string flowString;
+            if (num_flows > 1)
+            {
+                flowString = "-flow" + std::to_string(index);
+            }
+
+            firstCwnd[index + 1] = true;
+            firstSshThr[index + 1] = true;
+            firstRtt[index + 1] = true;
+            firstRto[index + 1] = true;
+
+            Simulator::Schedule(Seconds(start_time * index + 0.00001),
+                                &TraceCwnd,
+                                prefix_file_name + flowString + "-cwnd.data",
+                                index + 1);
+            Simulator::Schedule(Seconds(start_time * index + 0.00001),
+                                &TraceSsThresh,
+                                prefix_file_name + flowString + "-ssth.data",
+                                index + 1);
+            Simulator::Schedule(Seconds(start_time * index + 0.00001),
+                                &TraceRtt,
+                                prefix_file_name + flowString + "-rtt.data",
+                                index + 1);
+            Simulator::Schedule(Seconds(start_time * index + 0.00001),
+                                &TraceRto,
+                                prefix_file_name + flowString + "-rto.data",
+                                index + 1);
+            Simulator::Schedule(Seconds(start_time * index + 0.00001),
+                                &TraceNextTx,
+                                prefix_file_name + flowString + "-next-tx.data",
+                                index + 1);
+            Simulator::Schedule(Seconds(start_time * index + 0.00001),
+                                &TraceInFlight,
+                                prefix_file_name + flowString + "-inflight.data",
+                                index + 1);
+            Simulator::Schedule(Seconds(start_time * index + 0.1),
+                                &TraceNextRx,
+                                prefix_file_name + flowString + "-next-rx.data",
+                                num_flows + index + 1);
+        }
+    }
+
+    if (pcap)
+    {
+        UnReLink.EnablePcapAll(prefix_file_name, true);
+        LocalLink.EnablePcapAll(prefix_file_name, true);
+    }
+
+    // Flow monitor
+    FlowMonitorHelper flowHelper;
+    if (flow_monitor)
+    {
+        flowHelper.InstallAll();
+    }
+
+    Simulator::Stop(Seconds(stop_time));
+    Simulator::Run();
+
+    if (flow_monitor)
+    {
+        flowHelper.SerializeToXmlFile(prefix_file_name + ".flowmonitor", true, true);
+    }
+
+    Simulator::Destroy();
+    return 0;
+}

timeserver/Makefile

@@ -0,0 +1,20 @@
+CC = gcc -Wall -std=c11 -pedantic
+SOURCES = timeserver.c 
+OBJECTS = timeserver.o 
+
+all: timeserver
+
+timeserver: $(OBJECTS)
+	$(CC) $(OBJECTS) -o timeserver
+
+timeserver.o: timeserver.c
+	$(CC) -c timeserver.c -o timeserver.o
+
+clean:
+	rm -f $(OBJECTS) timeserver timeserver.out
+
+clean_objects:
+	rm -f $(OBJECTS)
+
+run:
+	./timeserver

timeserver/README.md

@@ -0,0 +1,16 @@
+# Running the timeserver
+Use `make` to compile the timeserver.
+Use `make run` to run the timeserver. This will run on an infinite loop.
+Use `Ctrl+C` to stop the timeserver.
+
+## timeserver communication
+Communicating with the server can happen using netcat in UDP mode (-u flag).
+
+## timeserver information
+The timeserver runs on UDP port 8888.
+The timeserver will wait for `time\r\n` to be sent on this port, and if received,
+will send back a response of the time (in ms) since January 1st, 1970 (UNIX Epoch).
+
+## pcap information
+A demonstration of the timeserver has been captured with Wireshark in the 
+included `demo.pcap` file.

timeserver/timeserver.c

@@ -0,0 +1,83 @@
+// header files
+#include "timeserver.h"
+
+// constants
+// timeserver port is 8888
+#define TIMEPORT 8888
+#define BUFFER_SIZE 1024
+
+// prototypes
+
+// main function
+int main(int argc, char **argv)
+{
+    // initialize program (variables and structs)
+    bool quitFlag = true;
+    int socketTimeFD;
+    char message[BUFFER_SIZE];
+    struct sockaddr_in serverAddr, clientAddr;
+    memset(&serverAddr, 0, sizeof(serverAddr));
+    memset(&clientAddr, 0, sizeof(clientAddr));
+    // define a UDP socket
+    socketTimeFD = socket(AF_INET, SOCK_DGRAM, 0);
+    if(socketTimeFD < 0)
+    {
+        printf("Unable to create the socket.");
+        return -1;
+    }
+    // bind the UDP socket to port 8888 / TIMEPORT
+    serverAddr.sin_family = AF_INET;
+    serverAddr.sin_addr.s_addr = INADDR_ANY;
+    serverAddr.sin_port = htons(TIMEPORT);
+    int bindCheck = bind(socketTimeFD, &serverAddr, sizeof(serverAddr));
+    if(bindCheck < 0)
+    {
+        printf("Unable to bind the socket to the port or address.\n Is either in use?");
+        return -1;
+    }
+    // while loop to see if the "time\r\n" has been received (recv call?)
+    printf("Timeserver listening on port: %d\n", TIMEPORT);
+    while(quitFlag)
+    {
+        int clientAddrLen;
+        int receivedDataLen;
+        // grab the data from the client
+        receivedDataLen = recvfrom(socketTimeFD, message, BUFFER_SIZE, MSG_WAITALL, &clientAddr, &clientAddrLen);
+        message[receivedDataLen] = '\0';
+        // if "time\r\n" is received, then send() back the linux epoch.
+        if(strcmp(message, "time\n") == 0 || strcmp(message, "time\r\n") == 0)
+        {
+            // setup the reply message
+            char reply[BUFFER_SIZE];
+            // add the current time to the reply
+            sprintf(reply, "%d", time(NULL));
+            // send the reply to the requestee
+            sendto(socketTimeFD, (const char *)reply, strlen(reply), 0, (const struct sockaddr *) &clientAddr, clientAddrLen);
+            // log the time command recv'd
+            printf("\nServer received time. Replied with: %d\n", time(NULL));
+        }
+        else if (strcmp(message, "close\n") == 0 || strcmp(message, "quit\n") == 0 || strcmp(message, "q\n") == 0)
+        {
+            // if the server recv'd the close command, then close the server.
+            printf("\nServer received close.\n");
+            quitFlag = false;
+        }
+    }
+    // close the socket
+    close(socketTimeFD);
+    // profit???
+    return 0;
+}
+
+// function definitions
+
+/*
+Name: ???
+Process: ???
+Function Input/Parameters: ???
+Function Output/Parameters: ???
+Function Output/Returned: ???
+Device Input/Device: ???
+Device Output/Device: ???
+Dependencies: ???
+*/

timeserver/timeserver.h

@@ -0,0 +1,23 @@
+#ifndef TIMESERVER
+#define TIMESERVER
+
+// included libraries
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <stdbool.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <time.h>
+#include <unistd.h>
+#include <errno.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+// data structures
+
+// function prototypes
+
+#endif // TIMESERVER