retx-suppression-exponential.cpp

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
#include "retx-suppression-exponential.hpp"
#include "algorithm.hpp"

namespace nfd {
namespace fw {

const RetxSuppressionExponential::Duration RetxSuppressionExponential::DEFAULT_INITIAL_INTERVAL =
    time::milliseconds(1);
const float RetxSuppressionExponential::DEFAULT_MULTIPLIER = 2.0;
const RetxSuppressionExponential::Duration RetxSuppressionExponential::DEFAULT_MAX_INTERVAL =
    time::milliseconds(250);

class RetxSuppressionExponential::PitInfo : public StrategyInfo
{
public:
  static constexpr int
  getTypeId()
  {
    return 1020;
  }

  explicit
  PitInfo(const Duration& initialInterval)
    : suppressionInterval(initialInterval)
  {
  }

public:
  Duration suppressionInterval;
};

RetxSuppressionExponential::RetxSuppressionExponential(const Duration& initialInterval,
                                                       float multiplier,
                                                       const Duration& maxInterval)
  : m_initialInterval(initialInterval)
  , m_multiplier(multiplier)
  , m_maxInterval(maxInterval)
{
  BOOST_ASSERT(initialInterval > time::milliseconds::zero());
  BOOST_ASSERT(multiplier >= 1.0);
  BOOST_ASSERT(maxInterval >= initialInterval);
}

RetxSuppression::Result
RetxSuppressionExponential::decide(const Face& inFace, const Interest& interest,
                                   pit::Entry& pitEntry) const
{
  bool isNewPitEntry = !hasPendingOutRecords(pitEntry);
  if (isNewPitEntry) {
    return NEW;
  }

  time::steady_clock::TimePoint lastOutgoing = this->getLastOutgoing(pitEntry);
  time::steady_clock::TimePoint now = time::steady_clock::now();
  time::steady_clock::Duration sinceLastOutgoing = now - lastOutgoing;

  PitInfo* pi = pitEntry.insertStrategyInfo<PitInfo>(m_initialInterval).first;
  bool shouldSuppress = sinceLastOutgoing < pi->suppressionInterval;

  if (shouldSuppress) {
    return SUPPRESS;
  }

  pi->suppressionInterval = std::min(m_maxInterval,
      time::duration_cast<Duration>(pi->suppressionInterval * m_multiplier));
  return FORWARD;
}

} // namespace fw
} // namespace nfd