Check permissions

clients/permissions/permissions_darwin.go

@@ -0,0 +1,18 @@
+//go:build darwin
+
+package permissions
+
+import (
+	"fmt"
+	"os"
+)
+
+// CheckNativeInterfacePermissions checks if the process has sufficient
+// permissions to create a native TUN interface on macOS.
+// This typically requires root privileges.
+func CheckNativeInterfacePermissions() error {
+	if os.Geteuid() == 0 {
+		return nil
+	}
+	return fmt.Errorf("insufficient permissions: need root to create TUN interface on macOS")
+}