Feature: persistent wintun with GUID option (#301)

Fixes: #300

engine/parse_windows.go

@@ -0,0 +1,34 @@
+package engine
+
+import (
+	"net/url"
+
+	"github.com/gorilla/schema"
+	"golang.org/x/sys/windows"
+	wun "golang.zx2c4.com/wireguard/tun"
+
+	"github.com/xjasonlyu/tun2socks/v2/core/device"
+	"github.com/xjasonlyu/tun2socks/v2/core/device/tun"
+	"github.com/xjasonlyu/tun2socks/v2/internal/version"
+)
+
+func init() {
+	wun.WintunTunnelType = version.Name
+}
+
+func parseTUN(u *url.URL, mtu uint32) (device.Device, error) {
+	opts := struct {
+		GUID string
+	}{}
+	if err := schema.NewDecoder().Decode(&opts, u.Query()); err != nil {
+		return nil, err
+	}
+	if opts.GUID != "" {
+		guid, err := windows.GUIDFromString(opts.GUID)
+		if err != nil {
+			return nil, err
+		}
+		wun.WintunStaticRequestedGUID = &guid
+	}
+	return tun.Open(u.Host, mtu)
+}