Answer CTCP VERSION/PING/TIME/CLIENTINFO on service pseudo-clients and split over-long NOTICE/PRIVMSG lines under 512 bytes

modules/protocol/inspircd/src/lib.rs

@@ -420,10 +420,10 @@ impl Protocol for InspIrcd {
                 uid = uid, ts = self.ts, nick = nick, host = host, ident = ident, modes = self.service_modes, gecos = gecos
             ))],
             NetAction::Privmsg { from, to, text } => {
-                vec![format!(":{} PRIVMSG {} :{}", from, to, text)]
+                split_body(text).into_iter().map(|chunk| format!(":{} PRIVMSG {} :{}", from, to, chunk)).collect()
             }
             NetAction::Notice { from, to, text } => {
-                vec![format!(":{} NOTICE {} :{}", from, to, text)]
+                split_body(text).into_iter().map(|chunk| format!(":{} NOTICE {} :{}", from, to, chunk)).collect()
             }
             // Standard reply: encapsulate for the target's server to re-emit locally
             // (FAIL/WARN/NOTE aren't s2s-routable). ENCAP * so only the server the
@@ -694,6 +694,49 @@ fn reason(rest: &str) -> String {
     }
 }
 
+// Message-body bytes kept per PRIVMSG/NOTICE line. The whole IRC line is 512
+// bytes incl. CR-LF; leaving ~110 for the ircd-expanded `:nick!user@host CMD
+// target :` prefix keeps even a max-length bot source under the limit, so the
+// ircd never truncates a reply mid-word.
+const MAX_MSG_TEXT: usize = 400;
+
+// Split an over-long message body into `MAX_MSG_TEXT`-byte chunks, breaking on a
+// char boundary (and preferably a space) so no NOTICE/PRIVMSG line is truncated.
+// A CTCP body (contains 0x01) is never split — a split would strand its delimiter.
+fn split_body(text: &str) -> Vec<&str> {
+    if text.len() <= MAX_MSG_TEXT || text.contains('\x01') {
+        return vec![text];
+    }
+    let mut out = Vec::new();
+    let mut rest = text;
+    while rest.len() > MAX_MSG_TEXT {
+        let mut cut = MAX_MSG_TEXT;
+        while cut > 0 && !rest.is_char_boundary(cut) {
+            cut -= 1;
+        }
+        // Prefer to break at the last space in the back half of the window.
+        if let Some(sp) = rest[..cut].rfind(' ') {
+            if sp >= MAX_MSG_TEXT / 2 {
+                cut = sp;
+            }
+        }
+        if cut == 0 {
+            // A single word longer than the window: hard-split at a char boundary.
+            cut = rest.len().min(MAX_MSG_TEXT);
+            while !rest.is_char_boundary(cut) {
+                cut -= 1;
+            }
+        }
+        let (head, tail) = rest.split_at(cut);
+        out.push(head);
+        rest = tail.trim_start_matches(' ');
+    }
+    if !rest.is_empty() {
+        out.push(rest);
+    }
+    out
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -958,6 +1001,27 @@ mod tests {
         assert_eq!(lines, vec![":42S SVSPART 0IRAAAAAB #chan".to_string()]);
     }
 
+    #[test]
+    fn long_notice_splits_under_the_line_limit() {
+        let text = "word ".repeat(200).trim().to_string(); // 200 words, ~999 bytes
+        let lines = proto().serialize(&NetAction::Notice { from: "42SAAAAAA".into(), to: "0IRAAAAAB".into(), text });
+        assert!(lines.len() >= 3, "split into multiple lines, got {}", lines.len());
+        let mut words = 0;
+        for l in &lines {
+            assert!(l.len() <= 512, "each line under 512 bytes: {}", l.len());
+            let body = l.split_once(" :").expect("has a trailing param").1;
+            words += body.split_whitespace().count();
+        }
+        assert_eq!(words, 200, "every word preserved across the split");
+    }
+
+    #[test]
+    fn ctcp_body_is_never_split() {
+        let text = format!("\x01{}\x01", "A".repeat(700));
+        let lines = proto().serialize(&NetAction::Notice { from: "42SAAAAAA".into(), to: "0IRAAAAAB".into(), text });
+        assert_eq!(lines.len(), 1, "a CTCP body stays on one line (a split would strand its \\x01)");
+    }
+
     // Free-form text with embedded line breaks must not smuggle a second line
     // onto the link: the serializer strips CR/LF/NUL from every outbound line.
     #[test]

src/config.rs

@@ -414,8 +414,11 @@ pub struct Server {
     #[serde(default)]
     pub service_host: String,
     // User modes the service pseudo-clients (services + bots) are introduced with.
-    // Default "iHkBT": invisible, hideoper, servprotect (unkillable — needs the
-    // services server U-lined), bot, block-CTCP. Set per the ircd's loaded modules.
+    // Default "iHkB": invisible, hideoper, servprotect (unkillable — needs the
+    // services server U-lined), bot. NOT +T (block-CTCP): echo answers CTCP
+    // VERSION/PING/TIME/CLIENTINFO itself (and ignores the rest), so a blanket
+    // ircd block would only stop those introspection replies. Set per the ircd's
+    // loaded modules; add "T" back to have the ircd drop all CTCP instead.
     #[serde(default = "default_service_modes")]
     pub service_modes: String,
     // Oper type the service pseudo-clients are flagged with, so WHOIS shows
@@ -438,7 +441,7 @@ fn default_services_channel() -> String {
 }
 
 fn default_service_modes() -> String {
-    "iHkBT".to_string() // invisible, hideoper, servprotect, bot, block-CTCP (matches the doc above)
+    "iHkB".to_string() // invisible, hideoper, servprotect, bot — CTCP handled by echo, not blocked at the ircd
 }
 
 fn default_service_oper_type() -> String {

src/engine/dispatch.rs

@@ -1,6 +1,29 @@
 use super::*;
 
 impl Engine {
+    // Answer a CTCP query addressed to a service pseudo-client. Replies to the
+    // standard introspection queries via a CTCP NOTICE (the CTCP convention);
+    // ACTION and anything unrecognised get no reply at all — a services daemon must
+    // not treat `\x01VERSION\x01` as a bad command.
+    fn ctcp_reply(&self, svc_uid: &str, to: &str, text: &str) -> Option<NetAction> {
+        let body = text.trim_matches('\x01');
+        let mut parts = body.splitn(2, ' ');
+        let cmd = parts.next().unwrap_or("").to_ascii_uppercase();
+        let arg = parts.next().unwrap_or("");
+        let response = match cmd.as_str() {
+            "VERSION" => format!("VERSION echo services {}", env!("CARGO_PKG_VERSION")),
+            "PING" => format!("PING {arg}"),
+            "TIME" => format!("TIME {}", echo_api::human_time(self.now_secs())),
+            "CLIENTINFO" => "CLIENTINFO ACTION CLIENTINFO PING TIME VERSION".to_string(),
+            _ => return None, // ACTION and unknown CTCPs: stay silent
+        };
+        Some(NetAction::Notice {
+            from: svc_uid.to_string(),
+            to: to.to_string(),
+            text: format!("\x01{response}\x01"),
+        })
+    }
+
     // Route a PRIVMSG addressed to a service (by uid or nick) into that service,
     // handing it the sender's resolved nick, login state, and the account store.
     pub(crate) fn dispatch(&mut self, from: &str, to: &str, text: &str) -> Vec<NetAction> {
@@ -71,6 +94,21 @@ impl Engine {
                     }
                 }
             }
+            // A CTCP query to a service (a PRIVMSG wrapped in \x01) gets a proper
+            // CTCP NOTICE reply for VERSION/PING/TIME/CLIENTINFO, and is otherwise
+            // ignored — never bounced back as an "I don't know the command" notice.
+            if text.starts_with('\x01') {
+                let svc_uid = self.services.iter()
+                    .find(|s| to.eq_ignore_ascii_case(s.uid()) || to.eq_ignore_ascii_case(s.nick()))
+                    .map(|s| s.uid().to_string());
+                let mut out = Vec::new();
+                if let Some(uid) = svc_uid {
+                    if let Some(reply) = self.ctcp_reply(&uid, from, text) {
+                        out.push(reply);
+                    }
+                }
+                return out;
+            }
             let mut matched: Option<String> = None;
             {
                 let Self { services, network, db, .. } = self;

src/engine/tests.rs

@@ -4017,6 +4017,34 @@
         assert!(os(&mut e, "000AAAAAS", "AKILL LIST").iter().any(|a| matches!(a, NetAction::Notice { text, .. } if text.contains("No matching"))), "list now empty");
     }
 
+    #[test]
+    fn ctcp_query_to_a_service_replies_or_stays_silent() {
+        use echo_nickserv::NickServ;
+        let path = std::env::temp_dir().join("echo-ctcp.jsonl");
+        let _ = std::fs::remove_file(&path);
+        let db = Db::open(&path, "42S");
+        let mut e = Engine::new(
+            vec![Box::new(NickServ { uid: "42SAAAAAA".into(), guest_nick: "Guest".into(), guest_seq: 0 })],
+            db,
+        );
+        e.set_sid("42S".into());
+        e.handle(NetEvent::UserConnect { uid: "000AAAAAB".into(), nick: "alice".into(), host: "h".into(), ip: "0.0.0.0".into() });
+        let ns = |e: &mut Engine, t: &str| e.handle(NetEvent::Privmsg { from: "000AAAAAB".into(), to: "42SAAAAAA".into(), text: t.into() });
+
+        // VERSION → a CTCP NOTICE from the service, never an "unknown command".
+        let ver = ns(&mut e, "\x01VERSION\x01");
+        assert!(ver.iter().any(|a| matches!(a, NetAction::Notice { from, text, .. } if from == "42SAAAAAA" && text.starts_with("\x01VERSION echo") && text.ends_with('\x01'))), "VERSION reply: {ver:?}");
+        assert!(!ver.iter().any(|a| matches!(a, NetAction::Notice { text, .. } if text.contains("don't know"))), "no unknown-command bounce");
+        // PING echoes the token back verbatim.
+        assert!(ns(&mut e, "\x01PING tok123\x01").iter().any(|a| matches!(a, NetAction::Notice { text, .. } if text == "\x01PING tok123\x01")), "PING echo");
+        // ACTION and unrecognised CTCPs get no reply at all.
+        assert!(ns(&mut e, "\x01ACTION waves\x01").iter().all(|a| !matches!(a, NetAction::Notice { .. })), "ACTION silent");
+        assert!(ns(&mut e, "\x01FLOOBLE\x01").iter().all(|a| !matches!(a, NetAction::Notice { .. })), "unknown CTCP silent");
+        // A normal (non-CTCP) unknown command is still answered — the intercept
+        // didn't swallow ordinary routing.
+        assert!(ns(&mut e, "FLOOBLE").iter().any(|a| matches!(a, NetAction::Notice { text, .. } if text.contains("don't know"))), "normal unknown command still answered");
+    }
+
     // An account approaching expiry with an email on file is warned once by
     // email, isn't dropped while still in the window, and isn't warned twice.
     #[test]