Move all of tun into overlay (#577)

overlay/tun_windows.go

@@ -0,0 +1,74 @@
+//go:build !e2e_testing
+// +build !e2e_testing
+
+package overlay
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"os"
+	"path/filepath"
+	"runtime"
+	"syscall"
+
+	"github.com/sirupsen/logrus"
+)
+
+type Tun struct {
+	Device
+}
+
+func newTunFromFd(l *logrus.Logger, deviceFd int, cidr *net.IPNet, defaultMTU int, routes []Route, unsafeRoutes []Route, txQueueLen int) (ifce *Tun, err error) {
+	return nil, fmt.Errorf("newTunFromFd not supported in Windows")
+}
+
+func newTun(l *logrus.Logger, deviceName string, cidr *net.IPNet, defaultMTU int, routes []Route, unsafeRoutes []Route, txQueueLen int, multiqueue bool) (ifce *Tun, err error) {
+	if len(routes) > 0 {
+		return nil, fmt.Errorf("route MTU not supported in Windows")
+	}
+
+	useWintun := true
+	if err = checkWinTunExists(); err != nil {
+		l.WithError(err).Warn("Check Wintun driver failed, fallback to wintap driver")
+		useWintun = false
+	}
+
+	var inside Device
+	if useWintun {
+		inside, err = newWinTun(deviceName, cidr, defaultMTU, unsafeRoutes, txQueueLen)
+		if err != nil {
+			return nil, fmt.Errorf("Create Wintun interface failed, %w", err)
+		}
+	} else {
+		inside, err = newWindowsWaterTun(deviceName, cidr, defaultMTU, unsafeRoutes, txQueueLen)
+		if err != nil {
+			return nil, fmt.Errorf("Create wintap driver failed, %w", err)
+		}
+	}
+
+	return &Tun{
+		Device: inside,
+	}, nil
+}
+
+func checkWinTunExists() error {
+	myPath, err := os.Executable()
+	if err != nil {
+		return err
+	}
+
+	arch := runtime.GOARCH
+	switch arch {
+	case "386":
+		//NOTE: wintun bundles 386 as x86
+		arch = "x86"
+	}
+
+	_, err = syscall.LoadDLL(filepath.Join(filepath.Dir(myPath), "dist", "windows", "wintun", "bin", arch, "wintun.dll"))
+	return err
+}
+
+func (t *Tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
+	return nil, fmt.Errorf("TODO: multiqueue not implemented for windows")
+}