42-ft_irc

An implementation of an IRC (Internet Relay Chat) server in C++98. This project is part of the 42 school curriculum and focuses on network programming, non-blocking I/O, and the IRC protocol.

Overview

ft_irc is a multi-client IRC server that allows users to connect, join channels, and exchange messages in real-time. The server is built using standard C++98 and handles multiple simultaneous connections without using threads (relying on I/O multiplexing).

Key Features

• Multi-client support: Handles multiple connections concurrently.
• Channel Management: Create, join, part, and manage channels.
• Operator Privileges: Channel operators can kick, invite, and change channel modes.
• Real-time Messaging: Private messages and channel-wide broadcasts.
• Standard Protocol: Compatible with standard IRC clients.

Getting Started

Prerequisites

• A C++ compiler (g++) supporting C++98.
• make build tool.
• Google Test (required only for running the test suite).

Compilation

To compile the server, run:

make

This will generate the ircserv executable.

Running the Server

Launch the server by specifying a port and a password:

./ircserv <port> <password>

Example:

./ircserv 6667 my_secure_password

How IRC Works

Internet Relay Chat (IRC) is a text-based communication protocol that follows a client-server architecture.

1. Connection: Clients connect to a central server using a TCP/IP socket.
2. Messages: Communication consists of lines of text ending with \r\n. Each line is either a command (from client to server) or a reply (identifiable by a 3-digit numeric code from server to client).
3. State Management: The server keeps track of connected users and active channels. Messages sent to a channel are broadcast to all users joined to that channel.
4. Asynchronous: IRC handles multiple events simultaneously—users joining, leaving, and messaging—without requiring synchronous waiting.

Server Password

Security is a crucial part of server management. ft_irc requires a password at startup for two main reasons:

• Access Control: Only users who know the server password can successfully authenticate and register their presence on the network.
• Protocol Compliance: According to the IRC protocol, the PASS command must be sent before the NICK and USER commands during the initial connection handshake. If the password provided by the client doesn't match the one specified at server startup, the registration process will be aborted.

Command Usage Guide

To interact with the server, you can use a standard IRC client or a simple tool like nc (netcat). Below is a guide on how to perform common tasks.

1. Connecting and Registering

Before you can join channels or send messages, you must register your session:

PASS server_password
NICK my_nickname
USER username 0 * :Real Name

Note

In this implementation, you must send PASS first if the server was started with a password.

2. Channels

• Join a channel: JOIN #example
• Leave a channel: PART #example
• Change topic: TOPIC #example :New amazing topic
• Invite someone: INVITE other_user #example

3. Messaging

• Private Message: PRIVMSG target_user :Hello there!
• Channel Message: PRIVMSG #example :Hello everyone!

4. Operator Actions

If you are a channel operator (usually the person who created the channel), you can:

• Kick a user: KICK #example annoying_user :optional reason
• Change modes: MODE #example +i (set invite-only)

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Implemented Commands

The server implements a subset of the RFC 2812 protocol.

Command	Description	RFC Reference
PASS	Sets a connection password.	Section 3.1.1
NICK	Gives the user a nickname or changes the existing one.	Section 3.1.2
USER	Specifies the username, hostname, and realname for a user.	Section 3.1.3
JOIN	Join a specific channel.	Section 3.2.1
PART	Leave a specific channel.	Section 3.2.2
PRIVMSG	Send a private message to a user or a channel.	Section 3.3.1
QUIT	Terminates the client session.	Section 3.1.7
KICK	Eject a user from a channel (Operator only).	Section 3.2.8
INVITE	Invite a user to a channel.	Section 3.2.7
TOPIC	Change or view the channel topic.	Section 3.2.4
MODE	Change channel or user modes.	Section 3.1.5

Debug Commands

The following commands are implemented for internal debugging and server monitoring:

• @USERS: Lists all users currently connected to the server.
• @CHANNELS: Lists all active channels and their properties.

Testing

The project includes a comprehensive test suite using Google Test. To run the tests, use the following commands:

1. Install dependencies (if not already installed):

   make test-install

2. Run tests:

   make test-run

3. Run tests with Valgrind (to check for memory leaks):

   make test-run-val