Add handshake interface support for gVisor UDP

stack_system_windows.go

@@ -0,0 +1,25 @@
+package tun
+
+import (
+	"os"
+	"path/filepath"
+
+	"github.com/sagernet/sing-tun/internal/winfw"
+)
+
+func fixWindowsFirewall() error {
+	absPath, err := filepath.Abs(os.Args[0])
+	if err != nil {
+		return err
+	}
+	rule := winfw.FWRule{
+		Name:            "sing-tun (" + absPath + ")",
+		ApplicationName: absPath,
+		Enabled:         true,
+		Protocol:        winfw.NET_FW_IP_PROTOCOL_TCP,
+		Direction:       winfw.NET_FW_RULE_DIR_IN,
+		Action:          winfw.NET_FW_ACTION_ALLOW,
+	}
+	_, err = winfw.FirewallRuleAddAdvanced(rule)
+	return err
+}