rn_lookup
rnh->rnh_lookup = rn_lookup;
struct radix_node *rn_lookup(void *, void *, struct radix_node_head *);
ke = (struct pfr_kentry *)rn_lookup(&sa, &mask, head);
rnh->rnh_lookup = rn_lookup;
*rn_lookup(const void *, const void *, struct radix_node_head *),
rn = rn_lookup(v_arg, m_arg, head);