packet.h

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/* 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_PACKET_H_
#define BM_BM_SIM_PACKET_H_
 
#include <array>
#include <memory>
#include <mutex>
#include <chrono>
#include <string>
#include <vector>
#include <atomic>
#include <algorithm>  // for std::min
#include <limits>
 
#include <cassert>
 
#include "device_id.h"
#include "packet_buffer.h"
#include "parser_error.h"
#include "phv_source.h"
#include "phv_forward.h"
 
namespace bm {
 
using packet_id_t = uint64_t;
 
using copy_id_t = uint64_t;
 
using port_t = uint32_t;
 
class CopyIdGenerator {
 private:
  static constexpr size_t W = 4096;
  struct Cntr {
    // if default member initializer used, then g++-5 complains for some reason,
    // so I had to provide an explicit constructor
    // clang complains if 'noexcept' is missing
    Cntr() noexcept : max(0), num(0) { }
    uint16_t max;
    uint16_t num;
  };
 
 public:
  copy_id_t add_one(packet_id_t packet_id);
 
  void remove_one(packet_id_t packet_id);
 
  copy_id_t get(packet_id_t packet_id);
 
  void reset(packet_id_t packet_id);
 
 private:
  std::array<std::atomic<Cntr>, W> arr{{}};
};
 
 
class Packet final {
  friend class SwitchWContexts;
  friend class Switch;
 
 public:
  using clock = std::chrono::system_clock;
 
  using buffer_state_t = PacketBuffer::state_t;
 
  static constexpr size_t nb_registers = 4u;
 
  static constexpr size_t INVALID_ENTRY_INDEX =
      std::numeric_limits<size_t>::max();
 
  ~Packet();
 
  packet_id_t get_packet_id() const { return packet_id; }
 
  int get_egress_port() const { return egress_port; }
  int get_ingress_port() const { return ingress_port; }
 
  void set_egress_port(int port) { egress_port = port; }
  void set_ingress_port(int port) { ingress_port = port; }
 
  copy_id_t get_copy_id() const { return copy_id; }
 
  const std::string get_unique_id() const {
    return std::to_string(packet_id) + "." + std::to_string(copy_id);
  }
 
  void set_copy_id(copy_id_t id) { copy_id = id; }
 
  int get_ingress_length() const { return ingress_length; }
 
  void set_ingress_length(int length) { ingress_length = length; }
 
  void set_payload_size(size_t size) { payload_size = size; }
 
  size_t get_payload_size() const { return payload_size; }
 
  size_t get_data_size() const {
    return std::min(buffer.get_data_size(), truncated_length);
  }
 
  char *data() { return buffer.start(); }
 
  const char *data() const { return buffer.start(); }
 
  const buffer_state_t save_buffer_state() const {
    return buffer.save_state();
  }
 
  void restore_buffer_state(const buffer_state_t &state) {
    buffer.restore_state(state);
  }
 
  char *payload() {
    assert(payload_size > 0);
    return buffer.end() - payload_size;
  }
 
  const char *payload() const {
    assert(payload_size > 0);
    return buffer.end() - payload_size;
  }
 
  void truncate(size_t length) {
    truncated_length = std::min(length, truncated_length);
  }
 
  char *prepend(size_t bytes) { return buffer.push(bytes); }
 
  char *remove(size_t bytes) {
    assert(buffer.get_data_size() >= payload_size + bytes);
    return buffer.pop(bytes);
  }
 
  uint64_t get_signature() const {
    return signature;
  }
 
  const PacketBuffer &get_packet_buffer() const { return buffer; }
 
  uint64_t get_ingress_ts_ms() const { return ingress_ts_ms; }
 
  // TODO(antonin): use references instead?
  PHV *get_phv() { return phv.get(); }
  const PHV *get_phv() const { return phv.get(); }
 
  void set_register(size_t idx, uint64_t v) { registers.at(idx) = v; }
  uint64_t get_register(size_t idx) { return registers.at(idx); }
 
  void set_entry_index(size_t idx) { entry_index = idx; }
  size_t get_entry_index() const { return entry_index; }
 
  void set_error_code(const ErrorCode &code) { error_code = code; }
  ErrorCode get_error_code() const { return error_code; }
 
  void set_checksum_error(const bool b) { checksum_error = b; }
  bool get_checksum_error() const { return checksum_error; }
 
  void mark_for_exit() { flags |= 1 << FLAGS_EXIT; }
  void reset_exit() { flags &= ~(1 << FLAGS_EXIT); }
  bool is_marked_for_exit() const { return flags & (1 << FLAGS_EXIT); }
 
  void change_context(cxt_id_t new_cxt);
 
  cxt_id_t get_context() const { return cxt_id; }
 
  // the *_ptr function are just here for convenience, the same can be achieved
  // by the client by constructing a unique_ptr
 
  Packet clone_with_phv() const;
  std::unique_ptr<Packet> clone_with_phv_ptr() const;
 
  Packet clone_with_phv_reset_metadata() const;
  std::unique_ptr<Packet> clone_with_phv_reset_metadata_ptr() const;
 
  Packet clone_no_phv() const;
  std::unique_ptr<Packet> clone_no_phv_ptr() const;
 
  Packet clone_choose_context(cxt_id_t new_cxt) const;
  std::unique_ptr<Packet> clone_choose_context_ptr(cxt_id_t new_cxt) const;
 
  Packet(const Packet &other) = delete;
  Packet &operator=(const Packet &other) = delete;
 
  Packet(Packet &&other) noexcept;
  Packet &operator=(Packet &&other) noexcept;
 
  // for tests
  // TODO(antonin): find a better solution, no-one is supposed to use these
  static Packet make_new(PHVSourceIface *phv_source);
  // cpplint false positive
  // NOLINTNEXTLINE(whitespace/operators)
  static Packet make_new(int ingress_length, PacketBuffer &&buffer,
                         PHVSourceIface *phv_source);
  static Packet make_new(cxt_id_t cxt, port_t ingress_port, packet_id_t id,
                         copy_id_t copy_id, int ingress_length,
                         // cpplint false positive
                         // NOLINTNEXTLINE(whitespace/operators)
                         PacketBuffer &&buffer, PHVSourceIface *phv_source);
 
 private:
  Packet(cxt_id_t cxt_id, port_t ingress_port, packet_id_t id,
         copy_id_t copy_id, int ingress_length, PacketBuffer &&buffer,
         PHVSourceIface *phv_source);
 
  void update_signature(uint64_t seed = 0);
  void set_ingress_ts();
 
  cxt_id_t cxt_id{0};
  port_t ingress_port{0};
  port_t egress_port{0};
  packet_id_t packet_id{0};
  copy_id_t copy_id{0};
  int ingress_length{0};
 
  enum PacketFlags {
    FLAGS_EXIT = 0
  };
  int flags{0};
 
  uint64_t signature{0};
 
  PacketBuffer buffer{};
 
  size_t payload_size{0};
 
  size_t truncated_length{std::numeric_limits<size_t>::max()};
 
  clock::time_point ingress_ts{};
  uint64_t ingress_ts_ms{};
 
  std::unique_ptr<PHV> phv;
 
  PHVSourceIface *phv_source{nullptr};
 
  // General purpose registers available to a target, they can be written with
  // Packet::set_register and read with Packet::get_register
  std::array<uint64_t, nb_registers> registers;
 
  // Used to store the index of the entry returned by the last match table
  // lookup; INVALID_ENTRY_INDEX if lookup was a miss.
  size_t entry_index{INVALID_ENTRY_INDEX};
 
  ErrorCode error_code{ErrorCode::make_invalid()};
 
  bool checksum_error{false};
 
 private:
  static CopyIdGenerator *copy_id_gen;
};
 
}  // namespace bm
 
#endif  // BM_BM_SIM_PACKET_H_