diff --git a/sys/netpfil/ipfw/ip_fw_private.h b/sys/netpfil/ipfw/ip_fw_private.h
index 1440b1a40ee..7ac92803b74 100644
--- a/sys/netpfil/ipfw/ip_fw_private.h
+++ b/sys/netpfil/ipfw/ip_fw_private.h
@@ -251,6 +251,20 @@ VNET_DECLARE(unsigned int, fw_tables_sets);
 
 struct tables_config;
 
+#ifndef V_hook_state
+typedef int (*ipfw_hook_t)(const void *arg);
+/* callback hooks for notify on update of internal states and aliases */
+VNET_DECLARE(ipfw_hook_t, hook_state);
+#define V_hook_state		VNET(hook_state)
+VNET_DECLARE(ipfw_hook_t, hook_alias);
+#define V_hook_alias		VNET(hook_alias)
+#endif
+
+#define ipfw_unregister_state_hook()	V_hook_state = NULL
+#define ipfw_unregister_alias_hook()	V_hook_alias = NULL
+#define ipfw_register_state_hook(_hcb)	V_hook_state = (_hcb)
+#define ipfw_register_alias_hook(_hcb)	V_hook_alias = (_hcb)
+
 #ifdef _KERNEL
 /*
  * Here we have the structure representing an ipfw rule.