vnet: fix route cleanup and reconnect backoff (#5492)

pkg/vnet/controller_test.go

@@ -0,0 +1,57 @@
+// Copyright 2026 The frp Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package vnet
+
+import (
+	"net"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	v1 "github.com/fatedier/frp/pkg/config/v1"
+)
+
+// TestClientRouterDeleteRouteRequiresMatchingConnection verifies that a stale
+// visitor cannot remove a replacement route registered under the same name.
+func TestClientRouterDeleteRouteRequiresMatchingConnection(t *testing.T) {
+	require := require.New(t)
+	controller := NewController(v1.VirtualNetConfig{})
+
+	_, route, err := net.ParseCIDR("10.1.0.1/32")
+	require.NoError(err)
+
+	oldConn, oldPeer := net.Pipe()
+	t.Cleanup(func() {
+		_ = oldConn.Close()
+		_ = oldPeer.Close()
+	})
+	replacementConn, replacementPeer := net.Pipe()
+	t.Cleanup(func() {
+		_ = replacementConn.Close()
+		_ = replacementPeer.Close()
+	})
+
+	controller.clientRouter.addRoute("vnet-visitor", []net.IPNet{*route}, oldConn)
+	controller.clientRouter.addRoute("vnet-visitor", []net.IPNet{*route}, replacementConn)
+
+	require.False(controller.UnregisterClientRoute("vnet-visitor", oldConn))
+	got, err := controller.clientRouter.findConn(net.ParseIP("10.1.0.1"))
+	require.NoError(err)
+	require.Same(replacementConn, got)
+
+	require.True(controller.UnregisterClientRoute("vnet-visitor", replacementConn))
+	_, err = controller.clientRouter.findConn(net.ParseIP("10.1.0.1"))
+	require.Error(err)
+}