strategy.hpp

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2014-2020,  Regents of the University of California,
 *                           Arizona Board of Regents,
 *                           Colorado State University,
 *                           University Pierre & Marie Curie, Sorbonne University,
 *                           Washington University in St. Louis,
 *                           Beijing Institute of Technology,
 *                           The University of Memphis.
 *
 * This file is part of NFD (Named Data Networking Forwarding Daemon).
 * See AUTHORS.md for complete list of NFD authors and contributors.
 *
 * NFD is free software: you can redistribute it and/or modify it under the terms
 * of the GNU General Public License as published by the Free Software Foundation,
 * either version 3 of the License, or (at your option) any later version.
 *
 * NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE.  See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef NFD_DAEMON_FW_STRATEGY_HPP
#define NFD_DAEMON_FW_STRATEGY_HPP

#include "forwarder.hpp"
#include "table/measurements-accessor.hpp"

namespace nfd {
namespace fw {

class Strategy : noncopyable
{
public: // registry
  template<typename S>
  static void
  registerType(const Name& strategyName = S::getStrategyName())
  {
    BOOST_ASSERT(strategyName.size() > 1);
    BOOST_ASSERT(strategyName.at(-1).isVersion());
    Registry& registry = getRegistry();
    BOOST_ASSERT(registry.count(strategyName) == 0);
    registry[strategyName] = [] (auto&&... args) {
      return make_unique<S>(std::forward<decltype(args)>(args)...);
    };
  }

  static bool
  canCreate(const Name& instanceName);

  static unique_ptr<Strategy>
  create(const Name& instanceName, Forwarder& forwarder);

  static bool
  areSameType(const Name& instanceNameA, const Name& instanceNameB);

  static std::set<Name>
  listRegistered();

public: // constructor, destructor, strategy info
  explicit
  Strategy(Forwarder& forwarder);

  virtual
  ~Strategy();

#ifdef DOXYGEN

  static const Name&
  getStrategyName();
#endif

  const Name&
  getInstanceName() const
  {
    return m_name;
  }

  bool
  wantNewNextHopTrigger() const
  {
    return m_wantNewNextHopTrigger;
  }

public: // triggers
  virtual void
  afterReceiveInterest(const FaceEndpoint& ingress, const Interest& interest,
                       const shared_ptr<pit::Entry>& pitEntry) = 0;

  virtual void
  beforeSatisfyInterest(const shared_ptr<pit::Entry>& pitEntry,
                        const FaceEndpoint& ingress, const Data& data);

  virtual void
  afterContentStoreHit(const shared_ptr<pit::Entry>& pitEntry,
                       const FaceEndpoint& ingress, const Data& data);

  virtual void
  afterReceiveData(const shared_ptr<pit::Entry>& pitEntry,
                   const FaceEndpoint& ingress, const Data& data);

  virtual void
  afterReceiveNack(const FaceEndpoint& ingress, const lp::Nack& nack,
                   const shared_ptr<pit::Entry>& pitEntry);

  virtual void
  onDroppedInterest(const Face& egress, const Interest& interest);

  virtual void
  afterNewNextHop(const fib::NextHop& nextHop, const shared_ptr<pit::Entry>& pitEntry);

protected: // actions
  VIRTUAL_WITH_TESTS pit::OutRecord*
  sendInterest(const shared_ptr<pit::Entry>& pitEntry, Face& egress,
               const Interest& interest);

  VIRTUAL_WITH_TESTS bool
  sendData(const shared_ptr<pit::Entry>& pitEntry, const Data& data, Face& egress);

  VIRTUAL_WITH_TESTS void
  sendDataToAll(const shared_ptr<pit::Entry>& pitEntry, const Face& inFace, const Data& data);

  VIRTUAL_WITH_TESTS void
  rejectPendingInterest(const shared_ptr<pit::Entry>& pitEntry)
  {
    this->setExpiryTimer(pitEntry, 0_ms);
  }

  VIRTUAL_WITH_TESTS bool
  sendNack(const shared_ptr<pit::Entry>& pitEntry, Face& egress,
           const lp::NackHeader& header)
  {
    return m_forwarder.onOutgoingNack(pitEntry, egress, header);
  }

  void
  sendNacks(const shared_ptr<pit::Entry>& pitEntry, const lp::NackHeader& header,
            std::initializer_list<const Face*> exceptFaces = {});

  void
  setExpiryTimer(const shared_ptr<pit::Entry>& pitEntry, time::milliseconds duration)
  {
    m_forwarder.setExpiryTimer(pitEntry, duration);
  }

protected: // accessors
  const fib::Entry&
  lookupFib(const pit::Entry& pitEntry) const;

  MeasurementsAccessor&
  getMeasurements()
  {
    return m_measurements;
  }

  Face*
  getFace(FaceId id) const
  {
    return getFaceTable().get(id);
  }

  const FaceTable&
  getFaceTable() const
  {
    return m_forwarder.m_faceTable;
  }

protected: // instance name
  struct ParsedInstanceName
  {
    Name strategyName; 
    optional<uint64_t> version; 
    PartialName parameters; 
  };

  static ParsedInstanceName
  parseInstanceName(const Name& input);

  static Name
  makeInstanceName(const Name& input, const Name& strategyName);

  void
  setInstanceName(const Name& name)
  {
    m_name = name;
  }

PUBLIC_WITH_TESTS_ELSE_PROTECTED: // setter
  void
  enableNewNextHopTrigger(bool enabled)
  {
    m_wantNewNextHopTrigger = enabled;
  }

private: // registry
  typedef std::function<unique_ptr<Strategy>(Forwarder& forwarder, const Name& strategyName)> CreateFunc;
  typedef std::map<Name, CreateFunc> Registry; // indexed by strategy name

  static Registry&
  getRegistry();

  static Registry::const_iterator
  find(const Name& instanceName);

protected: // accessors
  signal::Signal<FaceTable, Face>& afterAddFace;
  signal::Signal<FaceTable, Face>& beforeRemoveFace;

private: // instance fields
  Name m_name;

  Forwarder& m_forwarder;

  MeasurementsAccessor m_measurements;

  bool m_wantNewNextHopTrigger = false;
};

} // namespace fw
} // namespace nfd

#define NFD_REGISTER_STRATEGY(S)                       \
static class NfdAuto ## S ## StrategyRegistrationClass \
{                                                      \
public:                                                \
  NfdAuto ## S ## StrategyRegistrationClass()          \
  {                                                    \
    ::nfd::fw::Strategy::registerType<S>();            \
  }                                                    \
} g_nfdAuto ## S ## StrategyRegistrationVariable

#endif // NFD_DAEMON_FW_STRATEGY_HPP