diff --git a/sys/netlink/netlink.h b/sys/netlink/netlink.h
--- a/sys/netlink/netlink.h
+++ b/sys/netlink/netlink.h
@@ -194,11 +194,8 @@
 };
 
 
-#ifndef roundup2
-#define	roundup2(x, y)	(((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
-#endif
 #define	NL_ITEM_ALIGN_SIZE		sizeof(uint32_t)
-#define	NL_ITEM_ALIGN(_len)		roundup2(_len, NL_ITEM_ALIGN_SIZE)
+#define	NL_ITEM_ALIGN(_len)		__align_up(_len, NL_ITEM_ALIGN_SIZE)
 #define	NL_ITEM_DATA(_ptr, _off)	((void *)((char *)(_ptr) + _off))
 #define	NL_ITEM_DATA_CONST(_ptr, _off)	((const void *)((const char *)(_ptr) + _off))
 
@@ -208,25 +205,24 @@
 #define	NL_ITEM_ITER(_ptr, _len, _LEN_MACRO)	\
 	((_len) -= _LEN_MACRO(_ptr), NL_ITEM_NEXT(_ptr, _LEN_MACRO))
 
+/* part of netlink(3) API */
+#define	NLMSG_ALIGNTO			NL_ITEM_ALIGN_SIZE
+#define	NLMSG_ALIGN(_len)		NL_ITEM_ALIGN(_len)
 
 #ifndef _KERNEL
 /* part of netlink(3) API */
-#define NLMSG_ALIGNTO			NL_ITEM_ALIGN_SIZE
-#define NLMSG_ALIGN(_len)		NL_ITEM_ALIGN(_len)
-#define NLMSG_HDRLEN			((int)sizeof(struct nlmsghdr))
-#define NLMSG_LENGTH(_len)		((_len) + NLMSG_HDRLEN)
-#define NLMSG_SPACE(_len)		NLMSG_ALIGN(NLMSG_LENGTH(_len))
-#define NLMSG_DATA(_hdr)		NL_ITEM_DATA(_hdr, NLMSG_HDRLEN)
-#define	_NLMSG_LEN(_hdr)		((int)(_hdr)->nlmsg_len)
+#define	NLMSG_HDRLEN			(sizeof(struct nlmsghdr))
+#define	NLMSG_LENGTH(_len)		((_len) + NLMSG_HDRLEN)
+#define	NLMSG_SPACE(_len)		NLMSG_ALIGN(NLMSG_LENGTH(_len))
+#define	NLMSG_DATA(_hdr)		NL_ITEM_DATA(_hdr, NLMSG_HDRLEN)
+#define	_NLMSG_LEN(_hdr)		((_hdr)->nlmsg_len)
 #define	_NLMSG_ALIGNED_LEN(_hdr)	NLMSG_ALIGN(_NLMSG_LEN(_hdr))
 #define	NLMSG_OK(_hdr, _len)		NL_ITEM_OK(_hdr, _len, NLMSG_HDRLEN, _NLMSG_LEN)
 #define NLMSG_PAYLOAD(_hdr,_len)	(_NLMSG_LEN(_hdr) - NLMSG_SPACE((_len)))
 #define	NLMSG_NEXT(_hdr, _len)		NL_ITEM_ITER(_hdr, _len, _NLMSG_ALIGNED_LEN)
 
 #else
-#define NLMSG_ALIGNTO 4U
-#define NLMSG_ALIGN(len) (((len) + NLMSG_ALIGNTO - 1) & ~(NLMSG_ALIGNTO - 1))
-#define NLMSG_HDRLEN ((int)NLMSG_ALIGN(sizeof(struct nlmsghdr)))
+#define	NLMSG_HDRLEN			(NLMSG_ALIGN(sizeof(struct nlmsghdr)))
 #endif
 
 /*