Method DoAddField

core/utils/exact_match_table.h:391–443

Helper for public AddField functions. DoAddField inserts `field` as the `idx`th field for this table. If `mt_attr_name` is set, the `offset` field of `field` will be ignored and the inserted field will use the offset of `mt_attr_name` as reported by the module `m`. Returns 0 on success, non-zero errno on failure.

  // module `m`.
  // Returns 0 on success, non-zero errno on failure.
  Error DoAddField(const ExactMatchField &field,
                   const std::string &mt_attr_name, int idx,
                   Module *m = nullptr) {
    if (idx >= MAX_FIELDS) {
      return MakeError(EINVAL,
                       Format("idx %d is not in [0,%d)", idx, MAX_FIELDS));
    }
    ExactMatchField *f = &fields_[idx];
    f->size = field.size;
    if (f->size < 1 || f->size > MAX_FIELD_SIZE) {
      return MakeError(EINVAL, Format("idx %d: 'size' must be in [1,%d]", idx,
                                      MAX_FIELD_SIZE));
    }

    if (mt_attr_name.length() > 0) {
      f->attr_id = m->AddMetadataAttr(mt_attr_name, f->size,
                                      metadata::Attribute::AccessMode::kRead);
      if (f->attr_id < 0) {
        return MakeError(-f->attr_id,
                         Format("idx %d: add_metadata_attr() failed", idx));
      }
    } else {
      f->attr_id = -1;
      f->offset = field.offset;
      if (f->offset < 0 || f->offset > 1024) {
        return MakeError(EINVAL, Format("idx %d: invalid 'offset'", idx));
      }
    }

    int force_be = (f->attr_id < 0);

    if (field.mask == 0) {
      /* by default all bits are considered */
      f->mask = SetBitsHigh<uint64_t>(f->size * 8);
    } else {
      if (!utils::uint64_to_bin(&f->mask, field.mask, f->size,
                                utils::is_be_system() | force_be)) {
        return MakeError(
            EINVAL, Format("idx %d: not a valid %d-byte mask", idx, f->size));
      }
    }

    if (f->mask == 0) {
      return MakeError(EINVAL, Format("idx %d: empty mask", idx));
    }

    num_fields_++;
    f->pos = raw_key_size_;
    raw_key_size_ += f->size;
    total_key_size_ = align_ceil(raw_key_size_, sizeof(uint64_t));

    return MakeError(0);
  }

  // unaligend key size, used as an accumulator for calls to AddField()
  size_t raw_key_size_;