feat: set crrst flag on response header to ensure kitex client won't …

…reuse bad connections

pkg/remote/trans/default_server_handler.go

@@ -187,7 +187,7 @@ func (t *svrTransHandler) OnRead(ctx context.Context, conn net.Conn) (err error)
 	recvMsg.SetPayloadCodec(t.opt.PayloadCodec)
 	ctx, err = t.transPipe.Read(ctx, conn, recvMsg)
 	if err != nil {
-		t.writeErrorReplyIfNeeded(ctx, recvMsg, conn, err, ri, true)
+		t.writeErrorReplyIfNeeded(ctx, recvMsg, conn, err, ri, true, true)
 		// t.OnError(ctx, err, conn) will be executed at outer function when transServer close the conn
 		return err
 	}
@@ -203,7 +203,7 @@ func (t *svrTransHandler) OnRead(ctx context.Context, conn net.Conn) (err error)
 		var methodInfo serviceinfo.MethodInfo
 		if methodInfo, err = GetMethodInfo(ri, svcInfo); err != nil {
 			// it won't be error, because the method has been checked in decode, err check here just do defensive inspection
-			t.writeErrorReplyIfNeeded(ctx, recvMsg, conn, err, ri, true)
+			t.writeErrorReplyIfNeeded(ctx, recvMsg, conn, err, ri, true, true)
 			// for proxy case, need read actual remoteAddr, error print must exec after writeErrorReplyIfNeeded,
 			// t.OnError(ctx, err, conn) will be executed at outer function when transServer close the conn
 			return err
@@ -219,7 +219,7 @@ func (t *svrTransHandler) OnRead(ctx context.Context, conn net.Conn) (err error)
 			// error cannot be wrapped to print here, so it must exec before NewTransError
 			t.OnError(ctx, err, conn)
 			err = remote.NewTransError(remote.InternalError, err)
-			if closeConn := t.writeErrorReplyIfNeeded(ctx, recvMsg, conn, err, ri, false); closeConn {
+			if closeConn := t.writeErrorReplyIfNeeded(ctx, recvMsg, conn, err, ri, false, false); closeConn {
 				return err
 			}
 			// connection don't need to be closed when the error is return by the server handler
@@ -288,7 +288,7 @@ func (t *svrTransHandler) SetPipeline(p *remote.TransPipeline) {
 }
 
 func (t *svrTransHandler) writeErrorReplyIfNeeded(
-	ctx context.Context, recvMsg remote.Message, conn net.Conn, err error, ri rpcinfo.RPCInfo, doOnMessage bool,
+	ctx context.Context, recvMsg remote.Message, conn net.Conn, err error, ri rpcinfo.RPCInfo, doOnMessage bool, connReset bool,
 ) (shouldCloseConn bool) {
 	if cn, ok := conn.(remote.IsActive); ok && !cn.IsActive() {
 		// conn is closed, no need reply
@@ -313,6 +313,13 @@ func (t *svrTransHandler) writeErrorReplyIfNeeded(
 		// if error happen before normal OnMessage, exec it to transfer header trans info into rpcinfo
 		t.transPipe.OnMessage(ctx, recvMsg, errMsg)
 	}
+	if connReset {
+		// if connection needs to be closed, set ConnResetTag to response header
+		// to ensure the client won't reuse the connection.
+		if ei := rpcinfo.AsTaggable(ri.To()); ei != nil {
+			ei.SetTag(rpcinfo.ConnResetTag, "1")
+		}
+	}
 	ctx, err = t.transPipe.Write(ctx, conn, errMsg)
 	if err != nil {
 		klog.CtxErrorf(ctx, "KITEX: write error reply failed, remote=%s, error=%s", conn.RemoteAddr(), err.Error())