fix high cpu usage when client proto mismatch (#481)

before this patch, invalid packat received by tunnel reader may cause a dead loop in handshake.

easytier/src/peers/peer_conn.rs

@@ -133,15 +133,23 @@ impl PeerConn {
 
         let mut locked = self.recv.lock().await;
         let recv = locked.as_mut().unwrap();
-        let Some(rsp) = recv.next().await else {
-            return Err(Error::WaitRespError(
-                "conn closed during wait handshake response".to_owned(),
-            ));
+        let rsp = match recv.next().await {
+            Some(Ok(rsp)) => rsp,
+            Some(Err(e)) => {
+                return Err(Error::WaitRespError(format!(
+                    "conn recv error during wait handshake response, err: {:?}",
+                    e
+                )))
+            }
+            None => {
+                return Err(Error::WaitRespError(
+                    "conn closed during wait handshake response".to_owned(),
+                ))
+            }
         };
 
         *need_retry = true;
 
-        let rsp = rsp?;
         let Some(peer_mgr_hdr) = rsp.peer_manager_header() else {
             return Err(Error::WaitRespError(format!(
                 "unexpected packet: {:?}, cannot decode peer manager hdr",
@@ -214,6 +222,9 @@ impl PeerConn {
             Error::WaitRespError("send handshake request error".to_owned())
         })?;
 
+        // yield to send the response packet
+        tokio::task::yield_now().await;
+
         Ok(())
     }
 

easytier/src/tunnel/common.rs

@@ -75,18 +75,12 @@ pin_project! {
         #[pin]
         reader: R,
         buf: BytesMut,
-        state: FrameReaderState,
         max_packet_size: usize,
         associate_data: Option<Box<dyn Any + Send + 'static>>,
+        error: Option<TunnelError>,
     }
 }
 
-// usize means the size remaining to read
-enum FrameReaderState {
-    ReadingHeader(usize),
-    ReadingBody(usize),
-}
-
 impl<R> FramedReader<R> {
     pub fn new(reader: R, max_packet_size: usize) -> Self {
         Self::new_with_associate_data(reader, max_packet_size, None)
@@ -100,9 +94,9 @@ impl<R> FramedReader<R> {
         FramedReader {
             reader,
             buf: BytesMut::with_capacity(max_packet_size),
-            state: FrameReaderState::ReadingHeader(4),
             max_packet_size,
             associate_data,
+            error: None,
         }
     }
 
@@ -146,9 +140,19 @@ where
         let mut self_mut = self.project();
 
         loop {
+            if let Some(e) = self_mut.error.as_ref() {
+                tracing::warn!("poll_next on a failed FramedReader, {:?}", e);
+                return Poll::Ready(None);
+            }
+
             while let Some(packet) =
                 Self::extract_one_packet(self_mut.buf, *self_mut.max_packet_size)
             {
+                if let Err(TunnelError::InvalidPacket(msg)) = packet.as_ref() {
+                    self_mut
+                        .error
+                        .replace(TunnelError::InvalidPacket(msg.clone()));
+                }
                 return Poll::Ready(Some(packet));
             }