static int nh_fill_node(struct sk_buff *skb, struct nexthop *nh,
			int event, u32 portid, u32 seq, unsigned int nlflags)
static int nh_fill_node(struct sk_buff *skb, struct nexthop *nh,
			int event, u32 portid, u32 seq, unsigned int nlflags,
			u32 op_flags)