fix(proxy): improve connection cleanup and route validation handling

rust/crates/rustproxy-passthrough/src/quic_handler.rs

@@ -77,6 +77,13 @@ struct RelaySession {
     cancel: CancellationToken,
 }
 
+impl Drop for RelaySession {
+    fn drop(&mut self) {
+        self.cancel.cancel();
+        self.return_task.abort();
+    }
+}
+
 /// Create a QUIC endpoint with a PROXY protocol v2 relay layer.
 ///
 /// Instead of giving the external socket to quinn, we:
@@ -634,7 +641,7 @@ async fn forward_quic_stream_to_tcp(
     let la_watch = Arc::clone(&last_activity);
     let c2b_abort = c2b.abort_handle();
     let b2c_abort = b2c.abort_handle();
-    tokio::spawn(async move {
+    let watchdog = tokio::spawn(async move {
         let check_interval = std::time::Duration::from_secs(5);
         let mut last_seen = 0u64;
         loop {
@@ -665,6 +672,7 @@ async fn forward_quic_stream_to_tcp(
 
     let bytes_in = c2b.await.unwrap_or(0);
     let bytes_out = b2c.await.unwrap_or(0);
+    watchdog.abort();
 
     Ok((bytes_in, bytes_out))
 }