check_add_overflow
check_add_overflow((x), v, &v); \
if (check_add_overflow(addend1, addend2, &bytes))
if (check_add_overflow(pfa_ptr, (u16)(pfa_len - 1), &max_tlv)) {
if (check_add_overflow(next_tlv, (u16)2, &next_tlv) ||
check_add_overflow(next_tlv, tlv_len, &next_tlv)) {