ptree_matchkey
if (!ptree_matchkey(pt, key, ptn, bitoff, branch_bitoff - bitoff)) {
if (ptree_matchkey(pt, key, ptn, bitoff, mask_len - bitoff))
if (ptree_matchkey(pt, key, ptn, bitoff, UINT_MAX))
KASSERT(ptree_matchkey(pt, key, mask, 0, PTN_MASK_BITLEN(mask)));