modern.ircdocs.horseIRC Client Protocol Specification

This document is a heavy work in progress and should not be considered complete horse docs client protocol formatting ctcp dcc Modern IRC Client Protocol Jack Allnutt Kiwi IRC jack@allnutt.eu Daniel Oaks ircdocs daniel@danieloaks.net Val Lorentz [Editor] Limnoria vlorentz.ircdocs@isometry.eu This document intends to be a useful overview and reference of the IRC client protocol as it is implemented today. It is a living specification which is updated in response to feedback and implementations as they change. This document describes existing behaviour and what I consider best practices for new software. This is not a new protocol – it is the standard IRC protocol, just described in a single document with some already widely-implemented/accepted features and capabilities. Clients written to this spec will work with old and new servers, and servers written this way will service old and new clients. TL;DR if a new RFC was released today describing how IRC works, this is what I think it would look like. If something written in here isn’t correct for or interoperable with an IRC server / network you know of, please open an issue or contact me . NOTE: This is a WORK IN PROGRESS. All major points of the protocol are covered, but some common message and mode types are missing. You can contribute by sending pull requests to our GitHub repository ! Introduction The Internet Relay Chat (IRC) protocol has been designed over a number of years, with multitudes of implementations and use cases appearing. This document describes the IRC Client-Server protocol. IRC is a text-based chat protocol which has proven itself valuable and useful. It is well-suited to running on many machines in a distributed fashion. A typical setup involves multiple servers connected in a distributed network. Messages are delivered through this network and state is maintained across it for the connected clients and active channels. The key words MUST”, MUST NOT”, REQUIRED”, SHALL”, SHALL NOT”, SHOULD”, SHOULD NOT”, RECOMMENDED”, MAY”, and OPTIONAL” in this document are to be interpreted as described in RFC2119 . Table of Contents IRC Concepts Architectural Servers Clients Services Operators Channels Channel Operators Communication Types One-to-one communication One-to-many communication To A Channel To A Host/Server Mask To A List One-To-All Client-to-Client Client-to-Server Server-to-Server Connection Setup Server-to-Server Protocol Structure Client-to-Server Protocol Structure Message Format Tags Source Command Parameters Compatibility with incorrect software Numeric Replies Wildcard Expressions Connection Registration Feature Advertisement Capability Negotiation Client Messages Connection Messages CAP message AUTHENTICATE message PASS message NICK message USER message PING message PONG message OPER message QUIT message ERROR message Channel Operations JOIN message PART message TOPIC message NAMES message LIST message INVITE message Invite list KICK message Server Queries and Commands MOTD message VERSION Message ADMIN message CONNECT message LUSERS message TIME message STATS message HELP message INFO message MODE message User mode Channel mode Sending Messages PRIVMSG message NOTICE message User-Based Queries WHO message Examples WHOIS message Optional extensions Examples WHOWAS message Examples Operator Messages KILL message REHASH message RESTART message SQUIT message Optional Messages AWAY message LINKS message USERHOST message WALLOPS message Channel Types Regular Channels (#) Local Channels (&) Modes User Modes Invisible User Mode Oper User Mode Local Oper User Mode Registered User Mode WALLOPS User Mode Channel Modes Ban Channel Mode Exception Channel Mode Client Limit Channel Mode Invite-Only Channel Mode Invite-Exception Channel Mode Key Channel Mode Moderated Channel Mode Secret Channel Mode Protected Topic Mode No External Messages Mode Channel Membership Prefixes Founder Prefix Protected Prefix Operator Prefix Halfop Prefix Voice Prefix Numerics RPL_WELCOME (001) RPL_YOURHOST (002) RPL_CREATED (003) RPL_MYINFO (004) RPL_ISUPPORT (005) RPL_BOUNCE (010) RPL_STATSCOMMANDS (212) RPL_ENDOFSTATS (219) RPL_UMODEIS (221) RPL_STATSUPTIME (242) RPL_LUSERCLIENT (251) RPL_LUSEROP (252) RPL_LUSERUNKNOWN (253) RPL_LUSERCHANNELS (254) RPL_LUSERME (255) RPL_ADMINME (256) RPL_ADMINLOC1 (257) RPL_ADMINLOC2 (258) RPL_ADMINEMAIL (259) RPL_TRYAGAIN (263) RPL_LOCALUSERS (265) RPL_GLOBALUSERS (266) RPL_WHOISCERTFP (276) RPL_NONE (300) RPL_AWAY (301) RPL_USERHOST (302) RPL_UNAWAY (305) RPL_NOWAWAY (306) RPL_WHOISREGNICK (307) RPL_WHOISUSER (311) RPL_WHOISSERVER (312) RPL_WHOISOPERATOR (313) RPL_WHOWASUSER (314) RPL_ENDOFWHO (315) RPL_WHOISIDLE (317) RPL_ENDOFWHOIS (318) RPL_WHOISCHANNELS (319) RPL_WHOISSPECIAL (320) RPL_LISTSTART (321) RPL_LIST (322) RPL_LISTEND (323) RPL_CHANNELMODEIS (324) RPL_CREATIONTIME (329) RPL_WHOISACCOUNT (330) RPL_NOTOPIC (331) RPL_TOPIC (332) RPL_TOPICWHOTIME (333) RPL_INVITELIST (336) RPL_ENDOFINVITELIST (337) RPL_WHOISACTUALLY (338) RPL_INVITING (341) RPL_INVEXLIST (346) RPL_ENDOFINVEXLIST (347) RPL_EXCEPTLIST (348) RPL_ENDOFEXCEPTLIST (349) RPL_VERSION (351) RPL_WHOREPLY (352) RPL_NAMREPLY (353) RPL_LINKS (364) RPL_ENDOFLINKS (365) RPL_ENDOFNAMES (366) RPL_BANLIST (367) RPL_ENDOFBANLIST (368) RPL_ENDOFWHOWAS (369) RPL_INFO (371) RPL_MOTD (372) RPL_ENDOFINFO (374) RPL_MOTDSTART (375) RPL_ENDOFMOTD (376) RPL_WHOISHOST (378) RPL_WHOISMODES (379) RPL_YOUREOPER (381) RPL_REHASHING (382) RPL_TIME (391) ERR_UNKNOWNERROR (400) ERR_NOSUCHNICK (401) ERR_NOSUCHSERVER (402) ERR_NOSUCHCHANNEL (403) ERR_CANNOTSENDTOCHAN (404) ERR_TOOMANYCHANNELS (405) ERR_WASNOSUCHNICK (406) ERR_NOORIGIN (409) ERR_NORECIPIENT (411) ERR_NOTEXTTOSEND (412) ERR_INPUTTOOLONG (417) ERR_UNKNOWNCOMMAND (421) ERR_NOMOTD (422) ERR_NONICKNAMEGIVEN (431) ERR_ERRONEUSNICKNAME (432) ERR_NICKNAMEINUSE (433) ERR_NICKCOLLISION (436) ERR_USERNOTINCHANNEL (441) ERR_NOTONCHANNEL (442) ERR_USERONCHANNEL (443) ERR_NOTREGISTERED (451) ERR_NEEDMOREPARAMS (461) ERR_ALREADYREGISTERED (462) ERR_PASSWDMISMATCH (464) ERR_YOUREBANNEDCREEP (465) ERR_CHANNELISFULL (471) ERR_UNKNOWNMODE (472) ERR_INVITEONLYCHAN (473) ERR_BANNEDFROMCHAN (474) ERR_BADCHANNELKEY (475) ERR_BADCHANMASK (476) ERR_NOPRIVILEGES (481) ERR_CHANOPRIVSNEEDED (482) ERR_CANTKILLSERVER (483) ERR_NOOPERHOST (491) ERR_UMODEUNKNOWNFLAG (501) ERR_USERSDONTMATCH (502) ERR_HELPNOTFOUND (524) ERR_INVALIDKEY (525) RPL_STARTTLS (670) RPL_WHOISSECURE (671) ERR_STARTTLS (691) ERR_INVALIDMODEPARAM (696) RPL_HELPSTART (704) RPL_HELPTXT (705) RPL_ENDOFHELP (706) ERR_NOPRIVS (723) RPL_LOGGEDIN (900) RPL_LOGGEDOUT (901) ERR_NICKLOCKED (902) RPL_SASLSUCCESS (903) ERR_SASLFAIL (904) ERR_SASLTOOLONG (905) ERR_SASLABORTED (906) ERR_SASLALREADY (907) RPL_SASLMECHS (908) RPL_ISUPPORT Parameters AWAYLEN Parameter CASEMAPPING Parameter CHANLIMIT Parameter CHANMODES Parameter CHANNELLEN Parameter CHANTYPES Parameter ELIST Parameter EXCEPTS Parameter EXTBAN Parameter HOSTLEN Parameter INVEX Parameter KICKLEN Parameter MAXLIST Parameter MAXTARGETS Parameter MODES Parameter NETWORK Parameter NICKLEN Parameter PREFIX Parameter SAFELIST Parameter SILENCE Parameter STATUSMSG Parameter TARGMAX Parameter TOPICLEN Parameter USERLEN Parameter Current Architectural Problems Scalability Reliability Implementation Notes Character Encodings Message Parsing and Assembly Trailing Direct String Comparisons on IRC Lines Casemapping Servers Clients Obsolete Commands and Numerics Obsolete Commands Obsolete Numerics Acknowledgements IRC Concepts This section describes concepts behind the implementation and organisation of the IRC protocol, which are useful in understanding how it works. Architectural A typical IRC network consists of servers and clients connected to those servers, with a good mix of IRC operators and channels. This section goes through each of those, what they are and a brief overview of them. Servers Servers form the backbone of IRC, providing a point to which clients may connect and...