echoIRCd

A from-scratch IRC daemon written in native Rust. The architecture is inspired by InspIRCd's shape — commands as objects, modes as handler objects, modules with lifecycle hooks — but every line is original Rust, not a port or a translation. Design goals: #![forbid(unsafe_code)], dependency-light (just two small crates — openssl for TLS and mio for the epoll socket engine), and lock-free (a single core thread owns all state).

Status: early but capable. It boots, registers clients, speaks a large chunk of the IRC + IRCv3 protocol (see What works), and one reactor thread has served 5,000 concurrent connections in testing. Not battle-tested yet.

Run it

cp echoircd.conf.example echoircd.conf   # then edit: oper pass, cloak_key, TLS paths
cargo run --release                      # reads ./echoircd.conf
# point a client at it, e.g.  /server 127.0.0.1 6667

Config is plain key = value (see echoircd.conf.example). Your real echoircd.conf is gitignored because it holds secrets (oper password, cloak key, link password) — never commit it. For TLS, generate a cert/key into tls/ (the example config has the one-liner).

Architecture

A single core thread owns every User and Channel, so command and module code is plain single-threaded logic over &mut Server — no Arc<Mutex<…>> anywhere. The I/O edge feeds it events over mpsc channels:

• Client connections run on one mio epoll reactor thread. The daemon drives tens of thousands of sockets without a thread per connection — measured at 5,000 concurrent clients on 4 threads total, and it scales toward ~50k (use a release build and a high LimitNOFILE). This is the readiness layer Tokio is built on, but without pulling in an async runtime, so the single-threaded core is untouched.
• TLS and server links keep a thread per connection — there are few of them, and a TLS session can't be split across reader/writer threads.

Both models hand the core the same OutSink, so it never knows or cares which one a connection uses.

Where this improves on the C++ original it's inspired by: Uid handles instead of raw User* (no use-after-free, no cull list), an Extensible typemap instead of void* module data (freed automatically on drop), &str slices instead of char*, and compiled-in trait objects instead of a fragile .so ABI.

The two extension points

• Commands (src/command.rs, src/coremods/) — a handler declares name, min_params, before_reg and handle(&mut Server, uid, params), registered in command_table(). Adding a command is one struct + one table line.
• Modes (src/mode.rs) — channel/user modes are handler objects (ChanMode / UserMode) in a table; adding a mode never touches the parser.
• Modules (src/module.rs, src/modules/) — lifecycle hooks. Pre-hooks (on_user_register, on_pre_command, on_pre_message) return a ModResult and can Deny; notify-hooks fire from a queue after the command.

What works

• Registration (CAP/NICK/USER), PING/PONG with idle + registration timeouts, welcome burst (001–005) + ISUPPORT.
• JOIN/PART/NAMES/TOPIC/KICK/INVITE, PRIVMSG/NOTICE/TAGMSG, NICK, WHO/WHOIS/WHOWAS, LIST, AWAY, QUIT, MOTD/LUSERS.
• Full mode set as handler objects: prefixes +qaohv, lists +beI, and +klmntispzONCTcSRMGu plus flood/rate modes +f/+j/+F, redirect +L, word filter +g, and acting extbans m:/c:/n:.
• IRC operators: OPER/KILL/WALLOPS/GLOBOPS, SAJOIN/SAPART/SANICK/ SAMODE/SATOPIC/SAKICK, CHGHOST/CHGIDENT/SETHOST/SETIDENT, KLINE/GLINE/ZLINE + STATS, snomasks (+s), DIE/RESTART, and a reload-safe REHASH (keeps the running config if the file can't be read, and announces the reload to every connected user).
• IRCv3: CAP negotiation, server-time, message-tags + msgid, multi-prefix, away-notify, account-notify, extended-join, chghost, userhost-in-names, echo-message, invite-notify, setname, extended-monitor, SASL (PLAIN, relayed to services), WATCH/MONITOR, SILENCE, and ACCEPT + user +g callerid (only accepted users may PM you).
• Reverse-DNS on connect: the classic *** Looking up your hostname... connection notices, backed by a real forward-confirmed PTR resolver written from scratch over UDP (no DNS crate) — resolves clients to hostnames, off the core thread, fail-safe to the IP. Configurable (resolve_hosts, use_resolved_host).
• TLS (openssl) with sslinfo; keyed-SHA-256 host cloaking (+x); services-ready accounts (SVSLOGIN/SVSLOGOUT, account-gated +r/+R/+M) — the ircd is ready for an external services package, it is not one itself.
• Server-to-server linking: handshake, UID/FJOIN netburst, cross-server users and channels, nick-collision handling, netsplit.
• An antimixedutf8 anti-spam module (blocks mixed-script look-alike spam).

Provenance

echoIRCd is original Rust. InspIRCd is a reference for behaviour and API shape only — no code is copied or translated. scripts/native-rust-guard.sh enforces this (no unsafe, no C/FFI, dependencies limited to openssl + mio, and no copy/translation wording in comments); it runs on every edit.

License

See the repository for licensing.