Add ChanServ with channel registration

REGISTER/INFO/DROP with founder auth, stored as ChannelRegistered and
ChannelDropped events so channel registrations replicate across nodes
and compact like accounts. Registration requires an identified account;
only the founder can drop.

src/engine/db.rs

@@ -38,6 +38,16 @@ pub enum Event {
     AccountRegistered(Account),
     CertAdded { account: String, fp: String },
     CertRemoved { account: String, fp: String },
+    ChannelRegistered { name: String, founder: String, ts: u64 },
+    ChannelDropped { name: String },
+}
+
+// A registered channel and who owns it.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ChannelInfo {
+    pub name: String,
+    pub founder: String,
+    pub ts: u64,
 }
 
 // A durable record: the event plus the metadata a gossip layer needs to address
@@ -163,21 +173,22 @@ impl EventLog {
         self.entries.len()
     }
 
-    // Rewrite the log to a minimal snapshot: one AccountRegistered per account,
-    // authored under our origin at fresh sequence numbers. Peers re-converge
-    // because AccountRegistered overwrites and cert replay is idempotent. The
-    // version vector resets to our origin; peers re-advertise theirs on the next
-    // sync. Written to a temp file and renamed, so a crash leaves the old log.
-    fn compact(&mut self, accounts: &HashMap<String, Account>) -> std::io::Result<()> {
+    // Rewrite the log to a minimal snapshot: one event per live account and
+    // channel, authored under our origin at fresh sequence numbers. Peers
+    // re-converge because the register events overwrite and cert replay is
+    // idempotent. The version vector resets to our origin; peers re-advertise
+    // theirs on the next sync. Written to a temp file and renamed, so a crash
+    // leaves the old log.
+    fn compact(&mut self, events: Vec<Event>) -> std::io::Result<()> {
         let mut seq = self.next_seq();
-        let mut snapshot = Vec::with_capacity(accounts.len());
-        for account in accounts.values() {
+        let mut snapshot = Vec::with_capacity(events.len());
+        for event in events {
             self.lamport += 1;
             snapshot.push(LogEntry {
                 origin: self.origin.clone(),
                 seq,
                 lamport: self.lamport,
-                event: Event::AccountRegistered(account.clone()),
+                event,
             });
             seq += 1;
         }
@@ -213,6 +224,13 @@ pub enum CertError {
     Internal,   // persistence failed
 }
 
+#[derive(Debug)]
+pub enum ChanError {
+    Exists,     // channel already registered
+    NoChannel,  // channel is not registered
+    Internal,   // persistence failed
+}
+
 // A fingerprint is hex (hash digest), optionally colon-separated. Bound the
 // length so a junk value can't bloat an account.
 fn valid_fp(fp: &str) -> bool {
@@ -231,6 +249,7 @@ pub struct Credentials {
 
 pub struct Db {
     accounts: HashMap<String, Account>, // keyed by casefolded name
+    channels: HashMap<String, ChannelInfo>, // keyed by casefolded name
     log: EventLog,
     // PBKDF2 cost baked into new SCRAM verifiers; lowered by tests.
     pub(crate) scram_iterations: u32,
@@ -248,34 +267,40 @@ impl Db {
     pub fn open(path: impl Into<PathBuf>, origin: impl Into<String>) -> Self {
         let (log, events) = EventLog::open(path.into(), origin.into());
         let mut accounts = HashMap::new();
+        let mut channels = HashMap::new();
         for event in events {
-            apply(&mut accounts, event);
+            apply(&mut accounts, &mut channels, event);
         }
-        tracing::info!(accounts = accounts.len(), "account store loaded");
-        Self { accounts, log, scram_iterations: scram::DEFAULT_ITERATIONS }
+        tracing::info!(accounts = accounts.len(), channels = channels.len(), "account store loaded");
+        Self { accounts, channels, log, scram_iterations: scram::DEFAULT_ITERATIONS }
     }
 
     /// Fold an entry authored by another node into the store — the services-side
     /// of the gossip seam. Idempotent (re-delivered entries are dropped).
     pub fn ingest(&mut self, entry: LogEntry) -> std::io::Result<()> {
         if let Some(event) = self.log.ingest(entry)? {
-            apply(&mut self.accounts, event);
+            apply(&mut self.accounts, &mut self.channels, event);
         }
         Ok(())
     }
 
-    /// Rewrite the log to one entry per account, reclaiming churn.
+    /// Rewrite the log to one entry per account and channel, reclaiming churn.
     pub fn compact(&mut self) -> std::io::Result<()> {
         let before = self.log.len();
-        self.log.compact(&self.accounts)?;
+        let mut snapshot: Vec<Event> = self.accounts.values().cloned().map(Event::AccountRegistered).collect();
+        snapshot.extend(self.channels.values().map(|c| Event::ChannelRegistered {
+            name: c.name.clone(),
+            founder: c.founder.clone(),
+            ts: c.ts,
+        }));
+        self.log.compact(snapshot)?;
         tracing::info!(before, after = self.log.len(), "compacted event log");
         Ok(())
     }
 
-    /// Whether the log has grown enough past the live account count to be worth
-    /// compacting.
+    /// Whether the log has grown enough past the live state to be worth compacting.
     pub fn should_compact(&self) -> bool {
-        self.log.len() > self.accounts.len() * 3 + 64
+        self.log.len() > (self.accounts.len() + self.channels.len()) * 3 + 64
     }
 
     /// Wire the log to a broadcast channel; each new entry is pushed to peers.
@@ -396,11 +421,41 @@ impl Db {
         self.accounts.get_mut(&k).unwrap().certfps.retain(|c| *c != fp);
         Ok(true)
     }
+
+    /// Register `name` to `founder` (an account name).
+    pub fn register_channel(&mut self, name: &str, founder: &str) -> Result<(), ChanError> {
+        let k = key(name);
+        if self.channels.contains_key(&k) {
+            return Err(ChanError::Exists);
+        }
+        let ts = now();
+        self.log
+            .append(Event::ChannelRegistered { name: name.to_string(), founder: founder.to_string(), ts })
+            .map_err(|_| ChanError::Internal)?;
+        self.channels.insert(k, ChannelInfo { name: name.to_string(), founder: founder.to_string(), ts });
+        Ok(())
     }
 
-// Fold one event into the account map. Shared by log replay (`open`) and gossip
+    /// The registration for `name`, if any.
+    pub fn channel(&self, name: &str) -> Option<&ChannelInfo> {
+        self.channels.get(&key(name))
+    }
+
+    /// Unregister `name`.
+    pub fn drop_channel(&mut self, name: &str) -> Result<(), ChanError> {
+        let k = key(name);
+        if !self.channels.contains_key(&k) {
+            return Err(ChanError::NoChannel);
+        }
+        self.log.append(Event::ChannelDropped { name: name.to_string() }).map_err(|_| ChanError::Internal)?;
+        self.channels.remove(&k);
+        Ok(())
+    }
+}
+
+// Fold one event into the store. Shared by log replay (`open`) and gossip
 // ingest, so both routes reconstruct identical state.
-fn apply(accounts: &mut HashMap<String, Account>, event: Event) {
+fn apply(accounts: &mut HashMap<String, Account>, channels: &mut HashMap<String, ChannelInfo>, event: Event) {
     match event {
         Event::AccountRegistered(a) => {
             accounts.insert(key(&a.name), a);
@@ -417,6 +472,12 @@ fn apply(accounts: &mut HashMap<String, Account>, event: Event) {
                 a.certfps.retain(|c| *c != fp);
             }
         }
+        Event::ChannelRegistered { name, founder, ts } => {
+            channels.insert(key(&name), ChannelInfo { name, founder, ts });
+        }
+        Event::ChannelDropped { name } => {
+            channels.remove(&key(&name));
+        }
     }
 }
 
@@ -547,4 +608,21 @@ mod tests {
         assert!(b.exists("alice"), "B converges from a compacted node");
         assert_eq!(b.certfps("alice"), &[fp][..], "certs arrive folded into the snapshot");
     }
+
+    // Channels register (case-insensitively unique), persist, and drop.
+    #[test]
+    fn channels_register_drop_and_persist() {
+        let p = tmp("chan");
+        let mut db = Db::open(&p, "local");
+        db.register_channel("#Chat", "alice").unwrap();
+        assert!(matches!(db.register_channel("#chat", "bob"), Err(ChanError::Exists)), "dup is case-insensitive");
+        assert_eq!(db.channel("#CHAT").map(|c| c.founder.as_str()), Some("alice"));
+
+        drop(db);
+        let mut db = Db::open(&p, "local");
+        assert_eq!(db.channel("#chat").map(|c| c.founder.as_str()), Some("alice"), "survives reopen");
+        db.drop_channel("#chat").unwrap();
+        assert!(db.channel("#chat").is_none());
+        assert!(matches!(db.drop_channel("#chat"), Err(ChanError::NoChannel)));
+    }
 }

src/engine/mod.rs

@@ -896,4 +896,42 @@ mod tests {
         });
         assert!(out.iter().any(|a| matches!(a, NetAction::Metadata { key, value, .. } if key == "accountname" && value == "realnick")), "must log into the current nick's account: {out:?}");
     }
+
+    // ChanServ: registration needs identification, INFO shows the founder, and
+    // only the founder can drop.
+    #[test]
+    fn chanserv_register_info_drop() {
+        use crate::services::chanserv::ChanServ;
+        let path = std::env::temp_dir().join("fedserv-chanserv.jsonl");
+        let _ = std::fs::remove_file(&path);
+        let mut db = Db::open(&path, "42S");
+        db.scram_iterations = 4096;
+        db.register("alice", "sesame", None).unwrap();
+        let ns = NickServ { uid: "42SAAAAAA".into(), guest_nick: "Guest".into(), guest_seq: 0 };
+        let cs = ChanServ { uid: "42SAAAAAB".into() };
+        let mut e = Engine::new(vec![Box::new(ns), Box::new(cs)], db);
+
+        let to_cs = |e: &mut Engine, from: &str, text: &str| {
+            e.handle(NetEvent::Privmsg { from: from.into(), to: "42SAAAAAB".into(), text: text.into() })
+        };
+        let notice = |out: &[NetAction], needle: &str| {
+            out.iter().any(|a| matches!(a, NetAction::Notice { text, .. } if text.contains(needle)))
+        };
+        e.handle(NetEvent::UserConnect { uid: "000AAAAAB".into(), nick: "alice".into() });
+
+        // Not identified yet: refused.
+        assert!(notice(&to_cs(&mut e, "000AAAAAB", "REGISTER #room"), "must be identified"));
+
+        // Identify, then register.
+        e.handle(NetEvent::Privmsg { from: "000AAAAAB".into(), to: "42SAAAAAA".into(), text: "IDENTIFY sesame".into() });
+        assert!(notice(&to_cs(&mut e, "000AAAAAB", "REGISTER #room"), "now registered"));
+        assert!(notice(&to_cs(&mut e, "000AAAAAB", "INFO #room"), "alice"));
+
+        // A different, unidentified user cannot drop it.
+        e.handle(NetEvent::UserConnect { uid: "000AAAAAC".into(), nick: "bob".into() });
+        assert!(notice(&to_cs(&mut e, "000AAAAAC", "DROP #room"), "founder"));
+
+        // The founder can.
+        assert!(notice(&to_cs(&mut e, "000AAAAAB", "DROP #room"), "dropped"));
+    }
 }

src/main.rs

@@ -12,6 +12,7 @@ use tokio::sync::Mutex;
 
 use engine::Engine;
 use proto::inspircd::InspIrcd;
+use services::chanserv::ChanServ;
 use services::nickserv::NickServ;
 
 #[tokio::main]
@@ -35,11 +36,16 @@ async fn main() -> Result<()> {
         ts,
     ));
 
-    let services: Vec<Box<dyn engine::service::Service>> = vec![Box::new(NickServ {
+    let services: Vec<Box<dyn engine::service::Service>> = vec![
+        Box::new(NickServ {
             uid: format!("{}AAAAAA", cfg.server.sid),
             guest_nick: cfg.server.guest_nick.clone(),
             guest_seq: (ts % 100_000) as u32,
-    })];
+        }),
+        Box::new(ChanServ {
+            uid: format!("{}AAAAAB", cfg.server.sid),
+        }),
+    ];
     let (gossip_tx, _) = tokio::sync::broadcast::channel::<engine::db::LogEntry>(1024);
     let mut db = engine::db::Db::open("fedserv.db.jsonl", &cfg.server.sid);
     db.scram_iterations = cfg.server.scram_iterations;

src/services/chanserv.rs

@@ -0,0 +1,79 @@
+use crate::engine::db::{ChanError, Db};
+use crate::engine::service::{Sender, Service, ServiceCtx};
+
+pub struct ChanServ {
+    pub uid: String,
+}
+
+impl Service for ChanServ {
+    fn nick(&self) -> &str {
+        "ChanServ"
+    }
+    fn uid(&self) -> &str {
+        &self.uid
+    }
+    fn gecos(&self) -> &str {
+        "Channel Services"
+    }
+
+    fn on_command(&mut self, from: &Sender, args: &[&str], ctx: &mut ServiceCtx, db: &mut Db) {
+        let me = self.uid.as_str();
+        match args.first().map(|s| s.to_ascii_uppercase()).as_deref() {
+            Some("REGISTER") => {
+                let Some(&chan) = args.get(1) else {
+                    ctx.notice(me, from.uid, "Syntax: REGISTER <#channel>");
+                    return;
+                };
+                if !chan.starts_with('#') {
+                    ctx.notice(me, from.uid, "Channel names start with #.");
+                    return;
+                }
+                // The founder is the account the sender is identified to.
+                let Some(account) = from.account else {
+                    ctx.notice(me, from.uid, "You must be identified to register a channel.");
+                    return;
+                };
+                match db.register_channel(chan, account) {
+                    Ok(()) => ctx.notice(me, from.uid, format!("Channel \x02{chan}\x02 is now registered to \x02{account}\x02.")),
+                    Err(ChanError::Exists) => ctx.notice(me, from.uid, format!("\x02{chan}\x02 is already registered.")),
+                    Err(_) => ctx.notice(me, from.uid, "Registration failed, please try again later."),
+                }
+            }
+            Some("INFO") => {
+                let Some(&chan) = args.get(1) else {
+                    ctx.notice(me, from.uid, "Syntax: INFO <#channel>");
+                    return;
+                };
+                match db.channel(chan) {
+                    Some(info) => ctx.notice(me, from.uid, format!("\x02{}\x02 is registered to \x02{}\x02 (since {}).", info.name, info.founder, info.ts)),
+                    None => ctx.notice(me, from.uid, format!("\x02{chan}\x02 is not registered.")),
+                }
+            }
+            Some("DROP") => {
+                let Some(&chan) = args.get(1) else {
+                    ctx.notice(me, from.uid, "Syntax: DROP <#channel>");
+                    return;
+                };
+                // Read the founder, then drop, without holding the borrow across the mutation.
+                let founder = match db.channel(chan) {
+                    Some(info) => info.founder.clone(),
+                    None => {
+                        ctx.notice(me, from.uid, format!("\x02{chan}\x02 is not registered."));
+                        return;
+                    }
+                };
+                if from.account != Some(founder.as_str()) {
+                    ctx.notice(me, from.uid, "Only the channel founder can drop it.");
+                    return;
+                }
+                match db.drop_channel(chan) {
+                    Ok(()) => ctx.notice(me, from.uid, format!("Channel \x02{chan}\x02 has been dropped.")),
+                    Err(_) => ctx.notice(me, from.uid, "Drop failed, please try again later."),
+                }
+            }
+            Some("HELP") => ctx.notice(me, from.uid, "Commands: REGISTER <#channel>, INFO <#channel>, DROP <#channel>."),
+            Some(other) => ctx.notice(me, from.uid, format!("Unknown command: {other}. Try HELP.")),
+            None => {}
+        }
+    }
+}

src/services/mod.rs

@@ -1 +1,2 @@
+pub mod chanserv;
 pub mod nickserv;