diff --git a/src/utils/ip_addr.h b/src/utils/ip_addr.h
index 192049a58..28ccaefde 100644
--- a/src/utils/ip_addr.h
+++ b/src/utils/ip_addr.h
@@ -16,13 +16,14 @@
 #define IP_ADDR_H
 
 struct hostapd_ip_addr {
+	int af; /* AF_INET / AF_INET6 */
 	union {
 		struct in_addr v4;
 #ifdef CONFIG_IPV6
 		struct in6_addr v6;
 #endif /* CONFIG_IPV6 */
+		u8 max_len[16];
 	} u;
-	int af; /* AF_INET / AF_INET6 */
 };
 
 const char * hostapd_ip_txt(const struct hostapd_ip_addr *addr, char *buf,