diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index d1c7c90..5a42c36 100644
--- a/include/linux/rtnetlink.h
+++ b/include/linux/rtnetlink.h
@@ -7,6 +7,12 @@
 #include <linux/if_addr.h>
 #include <linux/neighbour.h>
 
+/* rtnetlink families. Values up to 127 are reserved for real address
+ * families, values above 128 may be used arbitrarily.
+ */
+#define RTNL_FAMILY_IPMR		128
+#define RTNL_FAMILY_MAX			128
+
 /****
  *		Routing/neighbour discovery messages.
  ****/