ft_irc

An IRC server written in C++98 using TCP sockets and poll(2) (42 school project).

This repository contains:

• mandatory/ — the IRC server (ircserv)
• bonus/ — a simple IRC bot (Bot) that can reply with quotes

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Features (high-level)

• Multiple clients handled with a single-threaded event loop (poll)
• Basic IRC registration flow (PASS, NICK, USER)
• Channels and messaging (JOIN, PRIVMSG)
• Channel moderation & management (KICK, TOPIC, MODE, INVITE)
• Graceful shutdown handling (SIGINT / SIGTERM)
• Bonus: bot that connects to the server and responds to !quote

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Prerequisites

• c++ compiler with C++98 support
• make
• An IRC client (recommended): irssi, weechat, hexchat
• Or nc / telnet for quick manual testing

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Build

Server (mandatory)

cd mandatory
make

Binary output:

• mandatory/ircserv

Bonus bot

cd bonus
make

Binary output:

• bonus/Bot

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Run

Start the server

From mandatory/:

./ircserv <port><password>

Example:

./ircserv 6667 secret

Notes:

• Port must be between 1 and 65535.
• Password must be non-empty.

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Connect with an IRC client

Using irssi (example):

/connect 127.0.0.1 6667 secret
/nick mynick
/user myuser 0 * :Real Name
/join #general

Quick connectivity test:

nc 127.0.0.1 6667

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Supported commands

The server reads commands line-by-line and accepts both \r\n and \n as line endings.

Recognized commands:

• PASS
• NICK
• USER
• JOIN
• PRIVMSG
• KICK
• TOPIC
• MODE
• INVITE

Unknown commands return: 421 <nick> <command> :Unknown command.

Registration (required)

Clients must authenticate first, then register.

PASS <password>

Authenticate using the server password (the one passed to ./ircserv <port> <password>).

• Must be called before registration.
• If the password is wrong, authentication fails.

Example:

PASS secret

NICK <nickname>

Set (or change) your nickname.

Rules implemented:

• Requires authentication (PASS) first; otherwise you get ERR_NOTREGISTERED.
• Nickname cannot start with: #, :, space, or a digit.
• Nickname must be unique.

Example:

NICK aragragu

If you change nick after being registered, the nick change is broadcast.

USER <username> <hostname> <servername> :<realname>

Set your username and real name and complete registration.

Rules implemented:

• Requires authentication (PASS) first.
• Refused if already registered.
• Realname can contain spaces when prefixed by :.

Example:

USER aragragu 0 * :Anas Rag

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Channels & messaging

JOIN #chan1,#chan2 [pass1,pass2]

Join one or more channels. Channels are comma-separated; passwords (if needed) can also be comma-separated.

Checks implemented:

• You must be registered.
• Channel name must start with # and not be just #.
• If channel is invite-only (+i), you must have been invited.
• If channel has a key (+k), you must provide the correct password.
• If channel has a user limit (+l), you cannot join if it is full.

Examples:

JOIN #general
JOIN #private mykey
JOIN #chan1,#chan2 pass1,pass2

When you join, the server sends JOIN + topic info (or “No topic is set”) and a names-style list (operators are prefixed with @ in that listing).

PRIVMSG <nick|#channel> :<message>

Send a private message to a user or a channel.

Rules implemented:

• You must be registered.
• You must provide a target and a message.
• If target is a channel, you must be a member of that channel; otherwise you get ERR_CANNOTSENDTOCHAN.

Examples:

PRIVMSG aragragu :hello!
PRIVMSG #general :hi everyone

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Moderation & channel management

KICK #channel user1[,user2...] [:reason]

Kick one or multiple users from a channel.

Rules implemented:

• You must be registered.
• You must be in the channel.
• You must be a channel operator to kick.
• The target user(s) must exist and be in the channel.

Examples:

KICK #general bob
KICK #general bob :spamming
KICK #general bob,alice :cleanup

If the channel becomes empty after removals, it is deleted.

TOPIC #channel (get) / TOPIC #channel :<new topic> (set)

Get or set the topic of a channel.

Rules implemented:

• Getting the topic:

  TOPIC #general
  

• Setting the topic:
  • requires you to be registered
  • requires you to be in the channel
  • if the channel has +t enabled, only channel operators can change the topic

Examples:

TOPIC #general :Welcome to #general
TOPIC #general

INVITE <nick> <#channel>

Invite a user to a channel.

Rules implemented:

• You must be registered.
• The target nick must exist.
• The channel must exist.
• You must be a member of the channel.
• If the channel is invite-only (+i), you must be a channel operator to invite.
• You cannot invite a user already in the channel.

Example:

INVITE bob #private

MODE #channel (query) / MODE #channel <modes> [params...] (set)

Query or set channel modes.

Query current modes

MODE #general

The server replies with a 324 numeric containing a mode string like:

• +i invite-only
• +t topic restricted to operators
• +k key/password set
• +l user limit set

Set modes (operator only)

Only channel operators can change modes.

Supported flags (as implemented):

• +i / -i — invite-only
• +t / -t — only operators can change topic
• +k <key> / -k — set/unset channel key
  • +k requires a parameter
  • if a key is already set, it returns an error
• +l <limit> / -l — set/unset user limit
  • +l requires a numeric limit > 0
• +o <nick> / -o <nick> — give/remove operator
  • target must exist and be in the channel

Examples:

MODE #general +i
MODE #general +t
MODE #general +k supersecret
MODE #general -k
MODE #general +l 10
MODE #general -l
MODE #general +o bob
MODE #general -o bob

When a mode change is applied, the server broadcasts:

:<setterNick> MODE #channel <modes> [params...]

to all channel members.

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Bonus: Quote bot

The bot connects to the server, registers, and joins #general automatically.

Build:

cd bonus && make

Run:

./Bot <server_ip><port><password>

Example:

./Bot 127.0.0.1 6667 secret

In #general, type:

• !quote
• !quote programming
• !quote music
• !quote adventure
• !quote life

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Project structure

.
├── mandatory/
│ ├── Makefile
│ ├── main.cpp
│ ├── Server.*
│ ├── Client.*
│ ├── channel.*
│ └── (handlers: Join/Pass/Nick/User/Privmsg/Kick/Topic/Mode/Invite/...)
└── bonus/
├── Makefile
└── Bot.*

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Common Makefile targets

Both mandatory/Makefile and bonus/Makefile provide:

make
make clean
make fclean
make re

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License

No license file is included in this repository.