diff --git a/sys/netlink/netlink_ctl.h b/sys/netlink/netlink_ctl.h
--- a/sys/netlink/netlink_ctl.h
+++ b/sys/netlink/netlink_ctl.h
@@ -79,7 +79,7 @@
 bool netlink_unregister_proto(int proto);
 
 /* Common helpers */
-bool nl_has_listeners(int netlink_family, uint32_t groups_mask);
+bool nl_has_listeners(uint16_t netlink_family, uint32_t groups_mask);
 bool nlp_has_priv(struct nlpcb *nlp, int priv);
 struct ucred *nlp_get_cred(struct nlpcb *nlp);
 uint32_t nlp_get_pid(const struct nlpcb *nlp);
@@ -103,7 +103,7 @@
 
 struct genl_family;
 const char *genl_get_family_name(const struct genl_family *gf);
-uint32_t genl_get_family_id(const struct genl_family *gf);
+uint16_t genl_get_family_id(const struct genl_family *gf);
 
 typedef void (*genl_family_event_handler_t)(void *arg, const struct genl_family *gf, int action);
 EVENTHANDLER_DECLARE(genl_family_event, genl_family_event_handler_t);
diff --git a/sys/netlink/netlink_domain.c b/sys/netlink/netlink_domain.c
--- a/sys/netlink/netlink_domain.c
+++ b/sys/netlink/netlink_domain.c
@@ -256,7 +256,7 @@
 }
 
 bool
-nl_has_listeners(int netlink_family, uint32_t groups_mask)
+nl_has_listeners(uint16_t netlink_family, uint32_t groups_mask)
 {
 	return (V_nl_ctl != NULL);
 }
diff --git a/sys/netlink/netlink_generic_kpi.c b/sys/netlink/netlink_generic_kpi.c
--- a/sys/netlink/netlink_generic_kpi.c
+++ b/sys/netlink/netlink_generic_kpi.c
@@ -252,7 +252,7 @@
 
 /* accessors */
 struct genl_family *
-genl_get_family(uint32_t family_id)
+genl_get_family(uint16_t family_id)
 {
 	return ((family_id < MAX_FAMILIES) ? &families[family_id] : NULL);
 }
@@ -263,7 +263,7 @@
 	return (gf->family_name);
 }
 
-uint32_t
+uint16_t
 genl_get_family_id(const struct genl_family *gf)
 {
 	return (gf->family_id);
diff --git a/sys/netlink/netlink_var.h b/sys/netlink/netlink_var.h
--- a/sys/netlink/netlink_var.h
+++ b/sys/netlink/netlink_var.h
@@ -159,7 +159,7 @@
 	const char		*group_name;
 };
 
-struct genl_family *genl_get_family(uint32_t family_id);
+struct genl_family *genl_get_family(uint16_t family_id);
 struct genl_group *genl_get_group(uint32_t group_id);
 
 #define	MAX_FAMILIES	20