modules: move all per-module state/config out of server.rs/config.rs into own files

src/modules/connflood.rs

@@ -0,0 +1,60 @@
+//! connflood — InspIRCd `m_connflood`. Refuse connections from an IP opening too
+//! many too fast. Config: `connflood = <max> <secs>`. Per-IP recent-connect times
+//! live in `Server.ext`, pruned on the tick — nothing lives on `Server`.
+
+use std::collections::HashMap;
+use std::net::IpAddr;
+
+use crate::module::Module;
+use crate::server::{now, Server};
+
+/// per-IP recent connection timestamps. Stored in `Server.ext`.
+#[derive(Default)]
+pub struct ConnHistory(pub HashMap<IpAddr, Vec<u64>>);
+
+/// `(max, secs)` from `connflood = <max> <secs>`, or `None` when disabled.
+fn cfg(s: &Server) -> Option<(u32, u64)> {
+    let v = s.conf("connflood")?;
+    let mut it = v.split_whitespace();
+    let mx: u32 = it.next()?.parse().ok()?;
+    let sc: u64 = it.next()?.parse().ok()?;
+    (mx > 0 && sc > 0).then_some((mx, sc))
+}
+
+/// Record a connection from `ip`; returns true when it exceeds the limit (the
+/// caller should refuse it). No-op → false when connflood is unconfigured.
+pub fn over_limit(s: &mut Server, ip: IpAddr) -> bool {
+    let Some((max, secs)) = cfg(s) else {
+        return false;
+    };
+    let n = now();
+    let hist = s
+        .ext
+        .get_or_insert_with::<ConnHistory>(ConnHistory::default)
+        .0
+        .entry(ip)
+        .or_default();
+    hist.retain(|&t| n.saturating_sub(t) < secs);
+    hist.push(n);
+    hist.len() as u32 > max
+}
+
+/// Prunes stale per-IP bookkeeping on the tick.
+pub struct ConnFlood;
+impl Module for ConnFlood {
+    fn name(&self) -> &'static str {
+        "connflood"
+    }
+    fn on_tick(&mut self, s: &mut Server) {
+        let Some((_, secs)) = cfg(s) else {
+            return;
+        };
+        let n = now();
+        if let Some(h) = s.ext.get_mut::<ConnHistory>() {
+            h.0.retain(|_, times| {
+                times.retain(|&t| n.saturating_sub(t) < secs);
+                !times.is_empty()
+            });
+        }
+    }
+}