checksums.h

/* Copyright 2013-present Barefoot Networks, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
/*
 * Antonin Bas (antonin@barefootnetworks.com)
 *
 */
 
#ifndef BM_BM_SIM_CHECKSUMS_H_
#define BM_BM_SIM_CHECKSUMS_H_
 
#include <string>
#include <memory>
 
#include "named_p4object.h"
#include "expressions.h"
 
namespace bm {
 
class Packet;
 
class NamedCalculation;
 
class Checksum : public NamedP4Object{
 public:
  Checksum(const std::string &name, p4object_id_t id,
           header_id_t header_id, int field_offset);
 
  virtual ~Checksum() = default;
 
  Checksum(const Checksum &other) = delete;
  Checksum &operator=(const Checksum &other) = delete;
 
  // The following are implictly deleted otherwise because of the user-defined
  // virtual destructor.
 
  Checksum(Checksum &&other) = default;
  Checksum &operator=(Checksum &&other) = default;
 
  void update(Packet *pkt) const;
 
  bool verify(const Packet &pkt) const;
 
  void set_checksum_condition(std::unique_ptr<Expression> cksum_condition);
 
 private:
  virtual void update_(Packet *pkt) const = 0;
  virtual bool verify_(const Packet &pkt) const = 0;
 
  bool is_checksum_condition_met(const Packet &pkt) const;
 
  bool is_target_field_valid(const Packet &pkt) const;
 
 protected:
  header_id_t header_id;
  int field_offset;
 
 private:
  std::unique_ptr<Expression> condition{nullptr};
};
 
class CalcBasedChecksum : public Checksum {
 public:
  CalcBasedChecksum(const std::string &name, p4object_id_t id,
                    header_id_t header_id, int field_offset,
                    const NamedCalculation *calculation);
 
  CalcBasedChecksum(const CalcBasedChecksum &other) = delete;
  CalcBasedChecksum &operator=(const CalcBasedChecksum &other) = delete;
 
  CalcBasedChecksum(CalcBasedChecksum &&other) = default;
  CalcBasedChecksum &operator=(CalcBasedChecksum &&other) = default;
 
 private:
  void update_(Packet *pkt) const override;
  bool verify_(const Packet &pkt) const override;
 
 private:
  const NamedCalculation *calculation{nullptr};
};
 
class IPv4Checksum : public Checksum {
 public:
  IPv4Checksum(const std::string &name, p4object_id_t id,
               header_id_t header_id, int field_offset);
 
 private:
  void update_(Packet *pkt) const override;
  bool verify_(const Packet &pkt) const override;
};
 
}  // namespace bm
 
#endif  // BM_BM_SIM_CHECKSUMS_H_