lp-reliability.hpp

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2014-2019,  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_FACE_LP_RELIABILITY_HPP
#define NFD_DAEMON_FACE_LP_RELIABILITY_HPP

#include "core/common.hpp"

#include <ndn-cxx/lp/packet.hpp>
#include <ndn-cxx/lp/sequence.hpp>
#include <ndn-cxx/util/rtt-estimator.hpp>

#include <queue>

namespace nfd {
namespace face {

class GenericLinkService;

class LpReliability : noncopyable
{
public:
  struct Options
  {
    bool isEnabled = false;

    size_t maxRetx = 3;

    time::nanoseconds idleAckTimerPeriod = 5_ms;

    size_t seqNumLossThreshold = 3;
  };

  LpReliability(const Options& options, GenericLinkService* linkService);

  signal::Signal<LpReliability, Interest> onDroppedInterest;

  void
  setOptions(const Options& options);

  const GenericLinkService*
  getLinkService() const;

  void
  handleOutgoing(std::vector<lp::Packet>& frags, lp::Packet&& pkt, bool isInterest);

  void
  processIncomingPacket(const lp::Packet& pkt);

  void
  piggyback(lp::Packet& pkt, ssize_t mtu);

PUBLIC_WITH_TESTS_ELSE_PRIVATE:
  class UnackedFrag;
  class NetPkt;
  using UnackedFrags = std::map<lp::Sequence, UnackedFrag>;

PUBLIC_WITH_TESTS_ELSE_PRIVATE:
  lp::Sequence
  assignTxSequence(lp::Packet& frag);

  void
  startIdleAckTimer();

  std::vector<lp::Sequence>
  findLostLpPackets(UnackedFrags::iterator ackIt);

  std::vector<lp::Sequence>
  onLpPacketLost(lp::Sequence txSeq);

  void
  onLpPacketAcknowledged(UnackedFrags::iterator fragIt);

  void
  deleteUnackedFrag(UnackedFrags::iterator fragIt);

PUBLIC_WITH_TESTS_ELSE_PRIVATE:
  class UnackedFrag
  {
  public:
    explicit
    UnackedFrag(lp::Packet pkt);

  public:
    lp::Packet pkt;
    scheduler::ScopedEventId rtoTimer;
    time::steady_clock::TimePoint sendTime;
    size_t retxCount;
    size_t nGreaterSeqAcks; 
    shared_ptr<NetPkt> netPkt;
  };

  class NetPkt
  {
  public:
    NetPkt(lp::Packet&& pkt, bool isInterest);

  public:
    std::vector<UnackedFrags::iterator> unackedFrags;
    lp::Packet pkt;
    bool isInterest;
    bool didRetx;
  };

public:
  static constexpr size_t RESERVED_HEADER_SPACE = tlv::sizeOfVarNumber(lp::tlv::TxSequence) +
                                                  tlv::sizeOfVarNumber(sizeof(lp::Sequence)) +
                                                  sizeof(lp::Sequence);

PUBLIC_WITH_TESTS_ELSE_PRIVATE:
  Options m_options;
  GenericLinkService* m_linkService;
  UnackedFrags m_unackedFrags;
  UnackedFrags::iterator m_firstUnackedFrag;
  std::queue<lp::Sequence> m_ackQueue;
  lp::Sequence m_lastTxSeqNo;
  scheduler::ScopedEventId m_idleAckTimer;
  ndn::util::RttEstimator m_rttEst;
};

} // namespace face
} // namespace nfd

#endif // NFD_DAEMON_FACE_LP_RELIABILITY_HPP