dead-nonce-list.cpp
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8  * Beijing Institute of Technology,
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25 
26 #include "dead-nonce-list.hpp"
27 #include "common/city-hash.hpp"
28 #include "common/global.hpp"
29 #include "common/logger.hpp"
30 
31 namespace nfd {
32 
33 NFD_LOG_INIT(DeadNonceList);
34 
35 DeadNonceList::DeadNonceList(time::nanoseconds lifetime)
36  : m_lifetime(lifetime)
37  , m_capacity(INITIAL_CAPACITY)
38  , m_markInterval(m_lifetime / EXPECTED_MARK_COUNT)
39  , m_adjustCapacityInterval(m_lifetime)
40 {
41  if (m_lifetime < MIN_LIFETIME) {
42  NDN_THROW(std::invalid_argument("lifetime is less than MIN_LIFETIME"));
43  }
44 
45  for (size_t i = 0; i < EXPECTED_MARK_COUNT; ++i) {
46  m_queue.push_back(MARK);
47  }
48 
49  m_markEvent = getScheduler().schedule(m_markInterval, [this] { mark(); });
50  m_adjustCapacityEvent = getScheduler().schedule(m_adjustCapacityInterval, [this] { adjustCapacity(); });
51 
52  BOOST_ASSERT_MSG(DEFAULT_LIFETIME >= MIN_LIFETIME, "DEFAULT_LIFETIME is too small");
53  static_assert(INITIAL_CAPACITY >= MIN_CAPACITY);
54  static_assert(INITIAL_CAPACITY <= MAX_CAPACITY);
55  BOOST_ASSERT_MSG(static_cast<size_t>(MIN_CAPACITY * CAPACITY_UP) > MIN_CAPACITY,
56  "CAPACITY_UP must be able to increase from MIN_CAPACITY");
57  BOOST_ASSERT_MSG(static_cast<size_t>(MAX_CAPACITY * CAPACITY_DOWN) < MAX_CAPACITY,
58  "CAPACITY_DOWN must be able to decrease from MAX_CAPACITY");
59  BOOST_ASSERT_MSG(CAPACITY_UP > 1.0, "CAPACITY_UP must adjust up");
60  BOOST_ASSERT_MSG(CAPACITY_DOWN < 1.0, "CAPACITY_DOWN must adjust down");
61  static_assert(EVICT_LIMIT >= 1);
62 }
63 
64 size_t
66 {
67  return m_queue.size() - countMarks();
68 }
69 
70 bool
71 DeadNonceList::has(const Name& name, Interest::Nonce nonce) const
72 {
73  Entry entry = DeadNonceList::makeEntry(name, nonce);
74  return m_ht.find(entry) != m_ht.end();
75 }
76 
77 void
78 DeadNonceList::add(const Name& name, Interest::Nonce nonce)
79 {
80  Entry entry = DeadNonceList::makeEntry(name, nonce);
81  const auto iter = m_ht.find(entry);
82  bool isDuplicate = iter != m_ht.end();
83 
84  NFD_LOG_TRACE("adding " << (isDuplicate ? "duplicate " : "") << name << " nonce=" << nonce);
85 
86  if (isDuplicate) {
87  m_queue.relocate(m_queue.end(), m_index.project<Queue>(iter));
88  }
89  else {
90  m_queue.push_back(entry);
91  evictEntries();
92  }
93 }
94 
95 DeadNonceList::Entry
96 DeadNonceList::makeEntry(const Name& name, Interest::Nonce nonce)
97 {
98  const auto& nameWire = name.wireEncode();
99  uint32_t n;
100  std::memcpy(&n, nonce.data(), sizeof(n));
101  return CityHash64WithSeed(reinterpret_cast<const char*>(nameWire.data()), nameWire.size(), n);
102 }
103 
104 size_t
105 DeadNonceList::countMarks() const
106 {
107  return m_ht.count(MARK);
108 }
109 
110 void
111 DeadNonceList::mark()
112 {
113  m_queue.push_back(MARK);
114  size_t nMarks = countMarks();
115  m_actualMarkCounts.insert(nMarks);
116 
117  NFD_LOG_TRACE("mark nMarks=" << nMarks);
118 
119  m_markEvent = getScheduler().schedule(m_markInterval, [this] { mark(); });
120 }
121 
122 void
123 DeadNonceList::adjustCapacity()
124 {
125  auto oldCapacity = m_capacity;
126  auto equalRange = m_actualMarkCounts.equal_range(EXPECTED_MARK_COUNT);
127  if (equalRange.second == m_actualMarkCounts.begin()) {
128  // all counts are above expected count, adjust down
129  m_capacity = std::max(MIN_CAPACITY, static_cast<size_t>(m_capacity * CAPACITY_DOWN));
130  }
131  else if (equalRange.first == m_actualMarkCounts.end()) {
132  // all counts are below expected count, adjust up
133  m_capacity = std::min(MAX_CAPACITY, static_cast<size_t>(m_capacity * CAPACITY_UP));
134  }
135 
136  if (m_capacity != oldCapacity) {
137  NFD_LOG_TRACE("adjusting capacity " << oldCapacity << " -> " << m_capacity);
138  }
139 
140  m_actualMarkCounts.clear();
141  evictEntries();
142 
143  m_adjustCapacityEvent = getScheduler().schedule(m_adjustCapacityInterval, [this] { adjustCapacity(); });
144 }
145 
146 void
147 DeadNonceList::evictEntries()
148 {
149  if (m_queue.size() <= m_capacity) // not over capacity
150  return;
151 
152  auto nEvict = std::min(m_queue.size() - m_capacity, EVICT_LIMIT);
153  for (size_t i = 0; i < nEvict; i++) {
154  m_queue.pop_front();
155  }
156  BOOST_ASSERT(m_queue.size() >= m_capacity);
157 
158  NFD_LOG_TRACE("evicted=" << nEvict << " size=" << size() << " capacity=" << m_capacity);
159 }
160 
161 } // namespace nfd
uint64 CityHash64WithSeed(const char *s, size_t len, uint64 seed)
Definition: city-hash.cpp:397
static constexpr time::nanoseconds MIN_LIFETIME
Minimum entry lifetime.
static constexpr time::nanoseconds DEFAULT_LIFETIME
Default entry lifetime.
DeadNonceList(time::nanoseconds lifetime=DEFAULT_LIFETIME)
Constructs the Dead Nonce List.
size_t size() const
Returns the number of stored nonces.
void add(const Name &name, Interest::Nonce nonce)
Adds name+nonce to the list.
bool has(const Name &name, Interest::Nonce nonce) const
Determines if name+nonce is in the list.
#define NFD_LOG_INIT(name)
Definition: logger.hpp:31
#define NFD_LOG_TRACE
Definition: logger.hpp:37
boost::multi_index_container< Policy::EntryRef, boost::multi_index::indexed_by< boost::multi_index::sequenced<>, boost::multi_index::ordered_unique< boost::multi_index::identity< Policy::EntryRef > > > > Queue
-status-http-server
Definition: common.hpp:71
ndn::Scheduler & getScheduler()
Returns the global Scheduler instance for the calling thread.
Definition: global.cpp:45