test tun

internal/wintun/wintun_windows.go

@@ -6,7 +6,7 @@
 package wintun
 
 import (
-	"runtime"
+	"log"
 	"syscall"
 	"unsafe"
 
@@ -30,6 +30,7 @@ var (
 )
 
 func closeAdapter(wintun *Adapter) {
+	log.Println("[tomi] closeAdapter")
 	syscall.SyscallN(procWintunCloseAdapter.Addr(), 1, wintun.handle, 0, 0)
 }
 
@@ -39,6 +40,7 @@ func closeAdapter(wintun *Adapter) {
 // deterministically. If it is set to nil, the GUID is chosen by the system at random,
 // and hence a new NLA entry is created for each new adapter.
 func CreateAdapter(name string, tunnelType string, requestedGUID *windows.GUID) (wintun *Adapter, err error) {
+	log.Println("[tomi] CreateAdapter")
 	var name16 *uint16
 	name16, err = windows.UTF16PtrFromString(name)
 	if err != nil {
@@ -55,12 +57,13 @@ func CreateAdapter(name string, tunnelType string, requestedGUID *windows.GUID)
 		return
 	}
 	wintun = &Adapter{handle: r0}
-	runtime.SetFinalizer(wintun, closeAdapter)
+	//runtime.SetFinalizer(wintun, closeAdapter)
 	return
 }
 
 // OpenAdapter opens an existing Wintun adapter by name.
 func OpenAdapter(name string) (wintun *Adapter, err error) {
+	log.Println("[tomi] OpenAdapter")
 	var name16 *uint16
 	name16, err = windows.UTF16PtrFromString(name)
 	if err != nil {
@@ -72,13 +75,15 @@ func OpenAdapter(name string) (wintun *Adapter, err error) {
 		return
 	}
 	wintun = &Adapter{handle: r0}
-	runtime.SetFinalizer(wintun, closeAdapter)
+	//runtime.SetFinalizer(wintun, closeAdapter)
 	return
 }
 
 // Close closes a Wintun adapter.
 func (wintun *Adapter) Close() (err error) {
-	runtime.SetFinalizer(wintun, nil)
+	log.Println("[tomi] CloseAdapter")
+
+	//runtime.SetFinalizer(wintun, nil)
 	r1, _, e1 := syscall.Syscall(procWintunCloseAdapter.Addr(), 1, wintun.handle, 0, 0)
 	if r1 == 0 {
 		err = e1

tun_windows.go

@@ -4,6 +4,7 @@ import (
 	"crypto/md5"
 	"errors"
 	"fmt"
+	"log"
 	"math"
 	"net"
 	"net/netip"
@@ -38,18 +39,49 @@ type NativeTun struct {
 	fwpmSession uintptr
 }
 
+var logPrefix = "[tomi][tun]"
+
 func New(options Options) (WinTun, error) {
 	if options.FileDescriptor != 0 {
 		return nil, os.ErrInvalid
 	}
-	adapter, err := wintun.CreateAdapter(options.Name, TunnelType, generateGUIDByDeviceName(options.Name))
+
+	var adapter *wintun.Adapter = nil
+
+	logPrefix = "[tomi][tun:" + options.Name + "]"
+	log.Println(logPrefix, "New() start")
+
+	// check tun device
+	netInterface, err := net.InterfaceByName(options.Name)
 	if err != nil {
-		return nil, err
+		log.Println(logPrefix, "find interface:", options.Name, ", failed:", err.Error())
+	}
+
+	if err == nil {
+		log.Println(logPrefix, "found interface:", netInterface.Name)
+	}
+
+	if err == nil && netInterface.Name == options.Name {
+		log.Println(logPrefix, "tun device found, just opening it")
+		adapter, err = wintun.OpenAdapter(options.Name)
+		if err != nil {
+			log.Println(logPrefix, "open tun adapter failed: "+err.Error())
+			return nil, errors.New("open tun adapter failed: " + err.Error())
+		}
+	} else {
+		log.Println(logPrefix, "tun device not found, create it")
+		adapter, err = wintun.CreateAdapter(options.Name, TunnelType, generateGUIDByDeviceName(options.Name))
+		if err != nil {
+			log.Println(logPrefix, "create tun adapter failed: "+err.Error())
+			return nil, errors.New("create tun adapter failed: " + err.Error())
+		}
 	}
+
 	nativeTun := &NativeTun{
 		adapter: adapter,
 		options: options,
 	}
+
 	session, err := adapter.StartSession(0x800000)
 	if err != nil {
 		return nil, err
@@ -58,10 +90,13 @@ func New(options Options) (WinTun, error) {
 	nativeTun.readWait = session.ReadWaitEvent()
 	err = nativeTun.configure()
 	if err != nil {
+		log.Println(logPrefix, "tun configure failed: "+err.Error())
 		session.End()
-		adapter.Close()
+		//adapter.Close()
 		return nil, err
 	}
+
+	log.Println(logPrefix, "New() done")
 	return nativeTun, nil
 }
 
@@ -522,20 +557,23 @@ func (t *NativeTun) WriteVectorised(buffers []*buf.Buffer) error {
 }
 
 func (t *NativeTun) Close() error {
+	log.Println(logPrefix, "Close() start")
 	var err error
 	t.closeOnce.Do(func() {
 		t.close.Store(1)
 		windows.SetEvent(t.readWait)
 		t.running.Wait()
 		t.session.End()
-		t.adapter.Close()
+		//t.adapter.Close()
 		if t.fwpmSession != 0 {
 			winsys.FwpmEngineClose0(t.fwpmSession)
 		}
 		if t.options.AutoRoute {
 			windnsapi.FlushResolverCache()
 		}
 	})
+
+	log.Println(logPrefix, "Close() done")
 	return err
 }