fix(web-client): time out stalled config-server dials (#2461)

Co-authored-by: 225284228a-droid <239500008+225284228a-droid@users.noreply.github.com>

easytier-core/src/management/full/web_client.rs

@@ -28,8 +28,19 @@ use super::{
 };
 
 const RETRY_INTERVAL: std::time::Duration = std::time::Duration::from_secs(1);
+// Keep retry ownership in this loop when transport or protocol handshakes stall.
+const CONNECT_TIMEOUT: std::time::Duration = std::time::Duration::from_secs(20);
 const FEATURE_TIMEOUT: std::time::Duration = std::time::Duration::from_secs(3);
 
+async fn connect_config_server(
+    connector: &dyn TunnelDialer,
+    timeout: std::time::Duration,
+) -> anyhow::Result<Box<dyn Tunnel>> {
+    time::timeout(timeout, connector.connect())
+        .await
+        .map_err(|_| anyhow::anyhow!("config-server connection timed out after {timeout:?}"))?
+}
+
 /// Normalized config-server endpoint and authentication token.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ConfigServerEndpoint {
@@ -164,7 +175,8 @@ where
         connector: Box<dyn TunnelDialer>,
     ) {
         loop {
-            let connection = match connector.connect().await {
+            let connection = match connect_config_server(connector.as_ref(), CONNECT_TIMEOUT).await
+            {
                 Ok(connection) => connection,
                 Err(error) => {
                     tracing::warn!(%error, "failed to connect to config server; retrying");
@@ -191,7 +203,9 @@ where
 
             if support_encryption && web_security::web_secure_tunnel_supported() {
                 drop(session);
-                let connection = match connector.connect().await {
+                let connection = match connect_config_server(connector.as_ref(), CONNECT_TIMEOUT)
+                    .await
+                {
                     Ok(connection) => connection,
                     Err(error) => {
                         connected.store(false, Ordering::Release);
@@ -364,7 +378,52 @@ where
 
 #[cfg(test)]
 mod tests {
+    use std::{
+        future::pending,
+        sync::atomic::{AtomicUsize, Ordering},
+    };
+
+    use async_trait::async_trait;
+
     use super::*;
+    use crate::tunnel::ring::create_ring_tunnel_pair;
+
+    struct StalledThenReadyDialer {
+        attempts: AtomicUsize,
+    }
+
+    #[async_trait]
+    impl TunnelDialer for StalledThenReadyDialer {
+        async fn connect(&self) -> anyhow::Result<Box<dyn Tunnel>> {
+            if self.attempts.fetch_add(1, Ordering::Relaxed) == 0 {
+                return pending().await;
+            }
+
+            let (tunnel, _peer) = create_ring_tunnel_pair();
+            Ok(tunnel)
+        }
+
+        fn remote_url(&self) -> Url {
+            "ring://config-server".parse().unwrap()
+        }
+    }
+
+    #[tokio::test]
+    async fn stalled_connection_attempt_times_out_and_allows_redial() {
+        let connector = StalledThenReadyDialer {
+            attempts: AtomicUsize::new(0),
+        };
+
+        let error = connect_config_server(&connector, std::time::Duration::from_millis(10))
+            .await
+            .unwrap_err();
+        assert!(error.to_string().contains("connection timed out"));
+
+        connect_config_server(&connector, std::time::Duration::from_secs(1))
+            .await
+            .unwrap();
+        assert_eq!(connector.attempts.load(Ordering::Relaxed), 2);
+    }
 
     #[test]
     fn endpoint_normalizes_non_websocket_paths() {