best-route-strategy2.cpp
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1 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
2 /*
3  * Copyright (c) 2014-2019, Regents of the University of California,
4  * Arizona Board of Regents,
5  * Colorado State University,
6  * University Pierre & Marie Curie, Sorbonne University,
7  * Washington University in St. Louis,
8  * Beijing Institute of Technology,
9  * The University of Memphis.
10  *
11  * This file is part of NFD (Named Data Networking Forwarding Daemon).
12  * See AUTHORS.md for complete list of NFD authors and contributors.
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14  * NFD is free software: you can redistribute it and/or modify it under the terms
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25 
26 #include "best-route-strategy2.hpp"
27 #include "algorithm.hpp"
28 #include "common/logger.hpp"
29 
30 namespace nfd {
31 namespace fw {
32 
33 NFD_LOG_INIT(BestRouteStrategy2);
34 NFD_REGISTER_STRATEGY(BestRouteStrategy2);
35 
36 const time::milliseconds BestRouteStrategy2::RETX_SUPPRESSION_INITIAL(10);
37 const time::milliseconds BestRouteStrategy2::RETX_SUPPRESSION_MAX(250);
38 
40  : Strategy(forwarder)
41  , ProcessNackTraits(this)
42  , m_retxSuppression(RETX_SUPPRESSION_INITIAL,
43  RetxSuppressionExponential::DEFAULT_MULTIPLIER,
44  RETX_SUPPRESSION_MAX)
45 {
47  if (!parsed.parameters.empty()) {
48  NDN_THROW(std::invalid_argument("BestRouteStrategy2 does not accept parameters"));
49  }
50  if (parsed.version && *parsed.version != getStrategyName()[-1].toVersion()) {
51  NDN_THROW(std::invalid_argument(
52  "BestRouteStrategy2 does not support version " + to_string(*parsed.version)));
53  }
55 }
56 
57 const Name&
59 {
60  static Name strategyName("/localhost/nfd/strategy/best-route/%FD%05");
61  return strategyName;
62 }
63 
64 void
65 BestRouteStrategy2::afterReceiveInterest(const FaceEndpoint& ingress, const Interest& interest,
66  const shared_ptr<pit::Entry>& pitEntry)
67 {
68  RetxSuppressionResult suppression = m_retxSuppression.decidePerPitEntry(*pitEntry);
69  if (suppression == RetxSuppressionResult::SUPPRESS) {
70  NFD_LOG_DEBUG(interest << " from=" << ingress << " suppressed");
71  return;
72  }
73 
74  const fib::Entry& fibEntry = this->lookupFib(*pitEntry);
75  const fib::NextHopList& nexthops = fibEntry.getNextHops();
76  auto it = nexthops.end();
77 
78  if (suppression == RetxSuppressionResult::NEW) {
79  // forward to nexthop with lowest cost except downstream
80  it = std::find_if(nexthops.begin(), nexthops.end(), [&] (const auto& nexthop) {
81  return isNextHopEligible(ingress.face, interest, nexthop, pitEntry);
82  });
83 
84  if (it == nexthops.end()) {
85  NFD_LOG_DEBUG(interest << " from=" << ingress << " noNextHop");
86 
87  lp::NackHeader nackHeader;
88  nackHeader.setReason(lp::NackReason::NO_ROUTE);
89  this->sendNack(pitEntry, ingress, nackHeader);
90 
91  this->rejectPendingInterest(pitEntry);
92  return;
93  }
94 
95  auto egress = FaceEndpoint(it->getFace(), 0);
96  NFD_LOG_DEBUG(interest << " from=" << ingress << " newPitEntry-to=" << egress);
97  this->sendInterest(pitEntry, egress, interest);
98  return;
99  }
100 
101  // find an unused upstream with lowest cost except downstream
102  it = std::find_if(nexthops.begin(), nexthops.end(), [&] (const auto& nexthop) {
103  return isNextHopEligible(ingress.face, interest, nexthop, pitEntry, true, time::steady_clock::now());
104  });
105 
106  if (it != nexthops.end()) {
107  auto egress = FaceEndpoint(it->getFace(), 0);
108  this->sendInterest(pitEntry, egress, interest);
109  NFD_LOG_DEBUG(interest << " from=" << ingress << " retransmit-unused-to=" << egress);
110  return;
111  }
112 
113  // find an eligible upstream that is used earliest
114  it = findEligibleNextHopWithEarliestOutRecord(ingress.face, interest, nexthops, pitEntry);
115  if (it == nexthops.end()) {
116  NFD_LOG_DEBUG(interest << " from=" << ingress << " retransmitNoNextHop");
117  }
118  else {
119  auto egress = FaceEndpoint(it->getFace(), 0);
120  this->sendInterest(pitEntry, egress, interest);
121  NFD_LOG_DEBUG(interest << " from=" << ingress << " retransmit-retry-to=" << egress);
122  }
123 }
124 
125 void
126 BestRouteStrategy2::afterReceiveNack(const FaceEndpoint& ingress, const lp::Nack& nack,
127  const shared_ptr<pit::Entry>& pitEntry)
128 {
129  this->processNack(ingress.face, nack, pitEntry);
130 }
131 
132 } // namespace fw
133 } // namespace nfd
Main class of NFD&#39;s forwarding engine.
Definition: forwarder.hpp:51
void setInstanceName(const Name &name)
set strategy instance name
Definition: strategy.hpp:382
void sendNack(const shared_ptr< pit::Entry > &pitEntry, const FaceEndpoint &egress, const lp::NackHeader &header)
send Nack to egress
Definition: strategy.hpp:302
represents a FIB entry
Definition: fib-entry.hpp:53
fib::NextHopList::const_iterator findEligibleNextHopWithEarliestOutRecord(const Face &inFace, const Interest &interest, const fib::NextHopList &nexthops, const shared_ptr< pit::Entry > &pitEntry)
pick an eligible NextHop with earliest out-record
Definition: algorithm.cpp:132
static const Name & getStrategyName()
BestRouteStrategy2(Forwarder &forwarder, const Name &name=getStrategyName())
Interest is retransmission and should be suppressed.
static Name makeInstanceName(const Name &input, const Name &strategyName)
construct a strategy instance name
Definition: strategy.cpp:134
void afterReceiveInterest(const FaceEndpoint &ingress, const Interest &interest, const shared_ptr< pit::Entry > &pitEntry) override
trigger after Interest is received
void sendInterest(const shared_ptr< pit::Entry > &pitEntry, const FaceEndpoint &egress, const Interest &interest)
send Interest to egress
Definition: strategy.cpp:197
Represents a face-endpoint pair in the forwarder.
Copyright (c) 2014-2015, Regents of the University of California, Arizona Board of Regents...
Definition: algorithm.hpp:32
Interest is new (not a retransmission)
void afterReceiveNack(const FaceEndpoint &ingress, const lp::Nack &nack, const shared_ptr< pit::Entry > &pitEntry) override
trigger after Nack is received
bool isNextHopEligible(const Face &inFace, const Interest &interest, const fib::NextHop &nexthop, const shared_ptr< pit::Entry > &pitEntry, bool wantUnused, time::steady_clock::TimePoint now)
determines whether a NextHop is eligible i.e.
Definition: algorithm.cpp:154
a retransmission suppression decision algorithm that suppresses retransmissions using exponential bac...
Represents a collection of nexthops.
Definition: fib-entry.hpp:39
PartialName parameters
parameter components
Definition: strategy.hpp:355
RetxSuppressionResult decidePerPitEntry(pit::Entry &pitEntry)
determines whether Interest is a retransmission per pit entry and if so, whether it shall be forwarde...
represents a forwarding strategy
Definition: strategy.hpp:37
This file contains common algorithms used by forwarding strategies.
#define NFD_LOG_DEBUG
Definition: logger.hpp:38
#define NFD_LOG_INIT(name)
Definition: logger.hpp:31
static ParsedInstanceName parseInstanceName(const Name &input)
parse a strategy instance name
Definition: strategy.cpp:123
void processNack(const Face &inFace, const lp::Nack &nack, const shared_ptr< pit::Entry > &pitEntry)
NFD_REGISTER_STRATEGY(SelfLearningStrategy)
const NextHopList & getNextHops() const
Definition: fib-entry.hpp:66
void rejectPendingInterest(const shared_ptr< pit::Entry > &pitEntry)
schedule the PIT entry for immediate deletion
Definition: strategy.hpp:289
const fib::Entry & lookupFib(const pit::Entry &pitEntry) const
performs a FIB lookup, considering Link object if present
Definition: strategy.cpp:288
optional< uint64_t > version
whether strategyName contains a version component
Definition: strategy.hpp:354