diff --git a/headers/posix/net/if.h b/headers/posix/net/if.h
index 73215b958a..f87648445e 100644
--- a/headers/posix/net/if.h
+++ b/headers/posix/net/if.h
@@ -80,6 +80,10 @@ struct ifconf {
 	};
 };
 
+#define _SIZEOF_ADDR_IFREQ(request) \
+	(sizeof((request).ifr_name) + (request).ifr_addr.sa_len)
+
+
 /* POSIX definitions follow */
 
 struct if_nameindex {