Internet Relay Chat

Contributors:

KakitaSama && Triangle && iamreda01

This project is an implementation of an IRC (Internet Relay Chat) server in C++98. The server handles multiple clients simultaneously, supports channel creation and management, and implements core IRC commands following the RFC 2119 protocol specification.

The server is capable of:

• Handling multiple client connections using non-blocking I/O and poll()
• Processing IRC commands including NICK, USER, JOIN, PRIVMSG, MODE, TOPIC, INVITE, KICK, PART, and PASS
• Managing channels with various modes (invite-only, topic restrictions, key-protected, user limits)
• Maintaining user authentication and registration
• Broadcasting messages to channels and users

Features

Core Features

• Client Authentication: PASS command for password verification
• User Registration: NICK and USER commands for client identification
• Channel Management:
  • JOIN command with channel creation
  • Channel modes: i (invite-only), t (topic restricted), k (key protected), l (user limit), o (operator)
• Messaging:
  • PRIVMSG for direct messages and channel broadcasts
  • TOPIC for channel topic management
• User Management:
  • INVITE to invite users to invite-only channels
  • KICK to remove users from channels (operator only)
  • PART to leave channels

Technical Features

• Non-blocking I/O using poll()
• Signal handling for graceful shutdown (SIGINT, SIGQUIT)
• Dynamic memory management for clients and channels
• Thread-safe design with no global state

Instructions

Compilation

The project includes a Makefile for compilation:

make

This will generate the ircserv executable.

Execution

Run the server with:

./ircserv <port> <password>

Parameters:

• <port>: The port number on which the server will listen (e.g., 6667)
• <password>: The connection password required by clients

Example:

./ircserv 6667 secretpass

Connecting with an IRC Client

You can connect to the server using any IRC client (like irssi, HexChat, or netcat):

Using netcat for testing:

nc localhost 6667

Then enter IRC commands manually:

PASS secretpass
NICK your_nickname
USER username 0 * :Real Name

Using a full IRC client:

/server localhost 6667 -pass secretpass

Available Commands

Command	Description
PASS <password>	Authenticate with the server
NICK <nickname>	Set or change your nickname
USER <username> 0 * :<realname>	Register your user information
JOIN <#channel>	Join or create a channel
PART <#channel>	Leave a channel
PRIVMSG <target> :<message>	Send a message to a user or channel
TOPIC <#channel> [<topic>]	View or set a channel's topic
MODE <#channel> [<modes> [<params>]]	Change channel modes
INVITE <nickname> <#channel>	Invite a user to an invite-only channel
KICK <#channel> <nickname> [:<reason>]	Remove a user from a channel (operator only)

Channel Modes

Mode	Description	Parameters
i	Invite-only	None
t	Topic restricted (operators only)	None
k	Key/password required	<key>
l	User limit	<limit>
o	Operator status	<nickname>

Examples:

• MODE #channel +i - Make channel invite-only
• MODE #channel +k secretkey - Set channel password
• MODE #channel +l 10 - Limit channel to 10 users
• MODE #channel +o username - Grant operator status

BOT Usage (The Nim Game)

The IRC server includes a built-in bot that allows users to play a game called Nim.

Game Rules

• The game contains 9 piles of objects, with each pile initially containing 9 objects.

• On your turn, you must choose exactly one pile.

• You must remove one or more objects from that chosen pile.

• You cannot remove objects from multiple piles in a single turn.

• The player who removes the very last object from the board wins the game.

How to Play for the First Time

• All interactions with the bot are done using the PRIVMSG command, using the syntax: PRIVMSG Bot : <amount>.

• Starting the game: To initiate your first game, send a message to the bot (e.g., PRIVMSG Bot : 1). Because it is your first interaction, the bot will reply with a welcome message, a list of the rules, and a visual display of the starting piles.

• Step 1 (Select a Pile): The bot will prompt you with, "Your turn, Choose pile index from 1 to 9". Send a PRIVMSG to the bot with your chosen pile number.

• Step 2 (Remove Stones): After selecting a valid pile, the bot will ask you how many stones you want to remove (from 1 up to the current total in that pile). Send another PRIVMSG with the amount you wish to remove.

• Bot's Turn: After your turn, the bot will automatically calculate its move, remove stones, and display the updated board state.

• Winning/Losing: You will alternate turns until all stones are gone. The bot will then announce if you beat it or if it won, and the game will reset for a new match.

Resources

IRC Protocol Documentation

https://modern.ircdocs.horse/

Additional Resources

• Server Basics: https://www.paessler.com/it-explained/server
• What is a Socket? (Reddit Discussion): https://www.reddit.com/r/learnprogramming/comments/12ifgcf/what_is_a_socket_what_does_it_mean_that_a/
• Socket in Computer Networks (GeeksforGeeks): https://www.geeksforgeeks.org/computer-networks/socket-in-computer-network/
• Socket Programming in C++ (GeeksforGeeks): https://www.geeksforgeeks.org/cpp/socket-programming-in-cpp/
• C++ Socket Programming (TutorialsPoint): https://www.tutorialspoint.com/cplusplus/cpp_socket_programming.htm
• Socket Programming Tutorial (YouTube): https://www.youtube.com/watch?v=XXfdzwEsxFk
• TCP/IP Model (GeeksforGeeks): https://www.geeksforgeeks.org/computer-networks/tcp-ip-model/

How AI Was Used

AI was used as a learning and documentation assistant throughout the project. It helped explain networking concepts, the IRC protocol, socket programming, and C++98 features, as well as assisted with debugging, code reviews, and improving the project's documentation. All implementation decisions, design, and final code were developed and validated by the project authors.