diff --git a/include/common/eb32tree.h b/include/common/eb32tree.h
index 87c2f98..f0c7930 100644
--- a/include/common/eb32tree.h
+++ b/include/common/eb32tree.h
@@ -17,6 +17,9 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
+#ifndef _COMMON_EB32TREE_H
+#define _COMMON_EB32TREE_H
+
 #include "ebtree.h"
 
 
@@ -511,3 +514,5 @@
 
 	return new;
 }
+
+#endif /* _COMMON_EB32TREE_H */