refactor dns task

src/server/resolver_task.rs

@@ -0,0 +1,40 @@
+use std::collections::HashSet;
+
+use tokio::{sync::mpsc::Sender, task::JoinHandle};
+
+use crate::{client::ClientHandle, dns::DnsResolver};
+
+use super::Server;
+
+#[derive(Clone)]
+pub struct DnsRequest {
+    pub hostname: String,
+    pub handle: ClientHandle,
+}
+
+pub fn new(resolver: DnsResolver, server: Server) -> (JoinHandle<()>, Sender<DnsRequest>) {
+    let (dns_tx, mut dns_rx) = tokio::sync::mpsc::channel::<DnsRequest>(32);
+    let resolver_task = tokio::task::spawn_local(async move {
+        loop {
+            let (host, handle) = match dns_rx.recv().await {
+                Some(r) => (r.hostname, r.handle),
+                None => break,
+            };
+            let ips = match resolver.resolve(&host).await {
+                Ok(ips) => ips,
+                Err(e) => {
+                    log::warn!("could not resolve host '{host}': {e}");
+                    continue;
+                }
+            };
+            if let Some(state) = server.client_manager.borrow_mut().get_mut(handle) {
+                let mut addrs = HashSet::from_iter(state.client.fix_ips.iter().cloned());
+                for ip in ips {
+                    addrs.insert(ip);
+                }
+                state.client.ips = addrs;
+            }
+        }
+    });
+    (resolver_task, dns_tx)
+}