#chaosircd

peace, love & hippie edition

chaosircd is an IRC daemon built around runtime-(re)loadable modules — every client command, channel mode, user mode, and flood-control check is its own .so, loaded and swapped without restarting the server. DNS, ident (RFC 1413), and proxy-scanning all run in a single dedicated child process, so a flood of connecting clients doesn't cost the main event loop a file descriptor or a blocked gethostbyname() each. Server links use timestamps for netsplit handling, in the same family as TS5/hybrid, and both server-server and client-server connections can run over OpenSSL.

#Why it exists

chaosircd started as patches to ircd-hybrid, written to keep a couple of real networks running: the IRC services behind irc.blah.ch at freemails.ch, and a handful of servers on a home cablemodem with a dynamic IP behind a dynamic-DNS hostname. Hybrid's server-linking wanted static addresses; a cablemodem doesn't have one, so the first real feature was teaching server links to resolve a hostname at connect time instead of requiring a bare IP. /SPOOF came soon after, so clients on that link could hide their real address the same way the servers already did.

From there the scope kept growing: a self-contained DNS resolver (lib/servauth/dns.c, in the classic djb two-file style), an open-proxy scanner, and an ident (port 113) client, all so a connecting client could be checked without trusting whatever it claimed about itself. K-lines and G-lines don't just refuse a banned client at the application layer — they hand the address to a BPF socket filter on Linux, so a client that's already been told to go away stops costing the daemon a read() at all.

Implementation began by lifting the dlink doubly-linked-list code straight out of ircd-hybrid — you can still see the family resemblance in lib/src/dlink.c — but everything built on top of it from that point on was written from scratch, and grew into its own daemon rather than staying a patch set.

That was 2003. The project has had long quiet stretches since — the git history jumps from an initial 2007 import to 2014 to 2026 — but each time it's come back to run something real, most recently a WebSocket gateway so a browser can join a chaosircd network with no separate bouncer process, and the start of an IRCv3 migration so modern clients (gamja, Kiwi, weechat's relay protocol, and friends) work with it properly instead of just well enough.

#Features

• Loadable modules for everything. Client commands, channel modes, user modes, and flood control (modules/msg, modules/chanmode, modules/usermode) are independent .so files — currently around 90 of them — loaded per modules.conf and swappable without a restart.
• A dedicated servauth process. lib/servauth/ runs DNS resolution, ident lookups, and proxy scanning for every connecting client in one child process (dns.c, auth.c, proxy.c), so the main daemon never blocks on any of the three.
• Hostname-based server links, for servers that don't have a static address to link to in the first place.
• /SPOOF, so a client's real address doesn't have to be their visible one.
• Socket-filter-backed K/G-lines. Bans push a BPF program onto the listening socket on Linux (lib/src/filter.c), so a banned address is refused before it costs the daemon a read.
• Timestamp-based netsplit handling for server-server links, in the same TS5/hybrid family, over plaintext or OpenSSL.
• A WebSocket gateway (lc_lws), self-hosting the gamja web client — see below.
• An IRCv3 migration underway — real CAP negotiation and echo-message landed first; the rest is planned out phase by phase.

#The WebSocket gateway

modules/lclient/lc_lws.c is an in-process WebSocket↔IRC gateway: a browser can speak IRC directly over ws:///wss:// to the same listener a normal client would use, no separate bouncer or relay process in between. It's built on libwebsockets, driven from chaosircd's own event loop rather than running a second one, and doubles as a static file server for a vendored, unmodified copy of gamja — a small IRC web client that needs no build step (no npm/yarn touches this repository; see CLAUDE.md). It's off by default, since it pulls in libwebsockets as a dependency nothing else here needs:

cmake -S . -B build -DBUILD_LC_LWS=ON
cmake --build build

#Building

chaosircd builds with CMake:

cmake -S . -B build
cmake --build build -j$(nproc)
sudo cmake --install build

See INSTALL for OpenSSL certificate generation and the BPF/socket-filter prerequisites for K/G-lines. Building loadable modules requires per-module shared-library support, on by default everywhere but Windows/Cygwin (BUILD_LIBIRCD, CMakeLists.txt).

#Status

Actively maintained, in long bursts separated by long quiet ones — this is primarily a project that gets worked on when it's running something for real. The IRCv3 migration plan is the current roadmap; that document also doubles as a running list of the non-obvious lessons this codebase has taught back to whoever's touching it next.

#License

The core library (lib/) is LGPL v2 or later; the daemon and its modules (src/, modules/) are GPL v2 or later — see the header of any given file for the exact terms, and COPYING / COPYING.LESSER for the full license texts.