Branch data Line data Source code
1 : : // Copyright (c) 2020-present The Bitcoin Core developers
2 : : // Distributed under the MIT software license, see the accompanying
3 : : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4 : :
5 : : #include <txrequest.h>
6 : :
7 : : #include <crypto/siphash.h>
8 : : #include <net.h>
9 : : #include <primitives/transaction.h>
10 : : #include <random.h>
11 : : #include <uint256.h>
12 : :
13 : : #include <boost/multi_index/indexed_by.hpp>
14 : : #include <boost/multi_index/ordered_index.hpp>
15 : : #include <boost/multi_index/sequenced_index.hpp>
16 : : #include <boost/multi_index/tag.hpp>
17 : : #include <boost/multi_index_container.hpp>
18 : : #include <boost/tuple/tuple.hpp>
19 : :
20 : : #include <chrono>
21 : : #include <unordered_map>
22 : : #include <utility>
23 : :
24 : : #include <cassert>
25 : :
26 : : namespace {
27 : :
28 : : /** The various states a (txhash,peer) pair can be in.
29 : : *
30 : : * Note that CANDIDATE is split up into 3 substates (DELAYED, BEST, READY), allowing more efficient implementation.
31 : : * Also note that the sorting order of ByTxHashView relies on the specific order of values in this enum.
32 : : *
33 : : * Expected behaviour is:
34 : : * - When first announced by a peer, the state is CANDIDATE_DELAYED until reqtime is reached.
35 : : * - Announcements that have reached their reqtime but not been requested will be either CANDIDATE_READY or
36 : : * CANDIDATE_BEST. Neither of those has an expiration time; they remain in that state until they're requested or
37 : : * no longer needed. CANDIDATE_READY announcements are promoted to CANDIDATE_BEST when they're the best one left.
38 : : * - When requested, an announcement will be in state REQUESTED until expiry is reached.
39 : : * - If expiry is reached, or the peer replies to the request (either with NOTFOUND or the tx), the state becomes
40 : : * COMPLETED.
41 : : */
42 : : enum class State : uint8_t {
43 : : /** A CANDIDATE announcement whose reqtime is in the future. */
44 : : CANDIDATE_DELAYED,
45 : : /** A CANDIDATE announcement that's not CANDIDATE_DELAYED or CANDIDATE_BEST. */
46 : : CANDIDATE_READY,
47 : : /** The best CANDIDATE for a given txhash; only if there is no REQUESTED announcement already for that txhash.
48 : : * The CANDIDATE_BEST is the highest-priority announcement among all CANDIDATE_READY (and _BEST) ones for that
49 : : * txhash. */
50 : : CANDIDATE_BEST,
51 : : /** A REQUESTED announcement. */
52 : : REQUESTED,
53 : : /** A COMPLETED announcement. */
54 : : COMPLETED,
55 : : };
56 : :
57 : : //! Type alias for sequence numbers.
58 : : using SequenceNumber = uint64_t;
59 : :
60 : : /** An announcement. This is the data we track for each txid or wtxid that is announced to us by each peer. */
61 : : struct Announcement {
62 : : /** Txid or wtxid that was announced. */
63 : : const GenTxid m_gtxid;
64 : : /** For CANDIDATE_{DELAYED,BEST,READY} the reqtime; for REQUESTED the expiry. */
65 : : std::chrono::microseconds m_time;
66 : : /** What peer the request was from. */
67 : : const NodeId m_peer;
68 : : /** What sequence number this announcement has. */
69 : : const SequenceNumber m_sequence : 59;
70 : : /** Whether the request is preferred. */
71 : : const bool m_preferred : 1;
72 : : /** What state this announcement is in. */
73 : : State m_state : 3 {State::CANDIDATE_DELAYED};
74 [ + + + + : 217537 : State GetState() const { return m_state; }
+ + - + -
+ ]
75 : 94767 : void SetState(State state) { m_state = state; }
76 : :
77 : : /** Whether this announcement is selected. There can be at most 1 selected peer per txhash. */
78 : 5437 : bool IsSelected() const
79 : : {
80 [ + + + + ]: 5437 : return GetState() == State::CANDIDATE_BEST || GetState() == State::REQUESTED;
81 : : }
82 : :
83 : : /** Whether this announcement is waiting for a certain time to pass. */
84 : 4268055 : bool IsWaiting() const
85 : : {
86 [ + + + + ]: 3758001 : return GetState() == State::REQUESTED || GetState() == State::CANDIDATE_DELAYED;
87 : : }
88 : :
89 : : /** Whether this announcement can feasibly be selected if the current IsSelected() one disappears. */
90 : 2525263 : bool IsSelectable() const
91 : : {
92 [ + + + + : 1650261 : return GetState() == State::CANDIDATE_READY || GetState() == State::CANDIDATE_BEST;
+ + + + ]
93 : : }
94 : :
95 : : /** Construct a new announcement from scratch, initially in CANDIDATE_DELAYED state. */
96 : 31501 : Announcement(const GenTxid& gtxid, NodeId peer, bool preferred, std::chrono::microseconds reqtime,
97 : : SequenceNumber sequence)
98 [ + - ]: 31501 : : m_gtxid(gtxid), m_time(reqtime), m_peer(peer), m_sequence(sequence), m_preferred(preferred) {}
99 : : };
100 : :
101 : : //! Type alias for priorities.
102 : : using Priority = uint64_t;
103 : :
104 : : /** A functor with embedded salt that computes priority of an announcement.
105 : : *
106 : : * Higher priorities are selected first.
107 : : */
108 : : class PriorityComputer {
109 : : const uint64_t m_k0, m_k1;
110 : : public:
111 : 1280 : explicit PriorityComputer(bool deterministic) :
112 [ + + ]: 1280 : m_k0{deterministic ? 0 : FastRandomContext().rand64()},
113 [ + + ]: 1280 : m_k1{deterministic ? 0 : FastRandomContext().rand64()} {}
114 : :
115 : 4294121 : Priority operator()(const uint256& txhash, NodeId peer, bool preferred) const
116 : : {
117 : 4294121 : uint64_t low_bits = CSipHasher(m_k0, m_k1).Write(txhash).Write(peer).Finalize() >> 1;
118 : 4294121 : return low_bits | uint64_t{preferred} << 63;
119 : : }
120 : :
121 : 2437897 : Priority operator()(const Announcement& ann) const
122 : : {
123 [ + + - ]: 4875794 : return operator()(ann.m_gtxid.ToUint256(), ann.m_peer, ann.m_preferred);
124 : : }
125 : : };
126 : :
127 : : // Definitions for the 3 indexes used in the main data structure.
128 : : //
129 : : // Each index has a By* type to identify it, a By*View data type to represent the view of announcement it is sorted
130 : : // by, and an By*ViewExtractor type to convert an announcement into the By*View type.
131 : : // See https://www.boost.org/doc/libs/1_58_0/libs/multi_index/doc/reference/key_extraction.html#key_extractors
132 : : // for more information about the key extraction concept.
133 : :
134 : : // The ByPeer index is sorted by (peer, state == CANDIDATE_BEST, txhash)
135 : : //
136 : : // Uses:
137 : : // * Looking up existing announcements by peer/txhash, by checking both (peer, false, txhash) and
138 : : // (peer, true, txhash).
139 : : // * Finding all CANDIDATE_BEST announcements for a given peer in GetRequestable.
140 : : struct ByPeer {};
141 : : using ByPeerView = std::tuple<NodeId, bool, const uint256&>;
142 : : struct ByPeerViewExtractor
143 : : {
144 : : using result_type = ByPeerView;
145 [ + + - + : 148900 : result_type operator()(const Announcement& ann) const
+ - ]
146 : : {
147 [ - - - + : 4088072 : return ByPeerView{ann.m_peer, ann.GetState() == State::CANDIDATE_BEST, ann.m_gtxid.ToUint256()};
+ - + + -
+ + - + +
- + + - +
+ - + + -
+ + - + +
- + + - +
+ - + + -
+ + - ]
148 : : }
149 : : };
150 : :
151 : : // The ByTxHash index is sorted by (txhash, state, priority).
152 : : //
153 : : // Note: priority == 0 whenever state != CANDIDATE_READY.
154 : : //
155 : : // Uses:
156 : : // * Deleting all announcements with a given txhash in ForgetTxHash.
157 : : // * Finding the best CANDIDATE_READY to convert to CANDIDATE_BEST, when no other CANDIDATE_READY or REQUESTED
158 : : // announcement exists for that txhash.
159 : : // * Determining when no more non-COMPLETED announcements for a given txhash exist, so the COMPLETED ones can be
160 : : // deleted.
161 : : struct ByTxHash {};
162 : : using ByTxHashView = std::tuple<const uint256&, State, Priority>;
163 : : class ByTxHashViewExtractor {
164 : : const PriorityComputer& m_computer;
165 : : public:
166 : 1280 : explicit ByTxHashViewExtractor(const PriorityComputer& computer) : m_computer(computer) {}
167 : : using result_type = ByTxHashView;
168 : 678871 : result_type operator()(const Announcement& ann) const
169 : : {
170 [ + + ]: 678871 : const Priority prio = (ann.GetState() == State::CANDIDATE_READY) ? m_computer(ann) : 0;
171 [ + + - ]: 678871 : return ByTxHashView{ann.m_gtxid.ToUint256(), ann.GetState(), prio};
172 : : }
173 : : };
174 : :
175 : : enum class WaitState {
176 : : //! Used for announcements that need efficient testing of "is their timestamp in the future?".
177 : : FUTURE_EVENT,
178 : : //! Used for announcements whose timestamp is not relevant.
179 : : NO_EVENT,
180 : : //! Used for announcements that need efficient testing of "is their timestamp in the past?".
181 : : PAST_EVENT,
182 : : };
183 : :
184 : 1146648 : WaitState GetWaitState(const Announcement& ann)
185 : : {
186 [ + + ]: 1146648 : if (ann.IsWaiting()) return WaitState::FUTURE_EVENT;
187 [ + + ]: 870683 : if (ann.IsSelectable()) return WaitState::PAST_EVENT;
188 : : return WaitState::NO_EVENT;
189 : : }
190 : :
191 : : // The ByTime index is sorted by (wait_state, time).
192 : : //
193 : : // All announcements with a timestamp in the future can be found by iterating the index forward from the beginning.
194 : : // All announcements with a timestamp in the past can be found by iterating the index backwards from the end.
195 : : //
196 : : // Uses:
197 : : // * Finding CANDIDATE_DELAYED announcements whose reqtime has passed, and REQUESTED announcements whose expiry has
198 : : // passed.
199 : : // * Finding CANDIDATE_READY/BEST announcements whose reqtime is in the future (when the clock time went backwards).
200 : : struct ByTime {};
201 : : using ByTimeView = std::pair<WaitState, std::chrono::microseconds>;
202 : : struct ByTimeViewExtractor
203 : : {
204 : : using result_type = ByTimeView;
205 : 1146648 : result_type operator()(const Announcement& ann) const
206 : : {
207 : 1146648 : return ByTimeView{GetWaitState(ann), ann.m_time};
208 : : }
209 : : };
210 : :
211 : :
212 : : /** Data type for the main data structure (Announcement objects with ByPeer/ByTxHash/ByTime indexes). */
213 : : using Index = boost::multi_index_container<
214 : : Announcement,
215 : : boost::multi_index::indexed_by<
216 : : boost::multi_index::ordered_unique<boost::multi_index::tag<ByPeer>, ByPeerViewExtractor>,
217 : : boost::multi_index::ordered_non_unique<boost::multi_index::tag<ByTxHash>, ByTxHashViewExtractor>,
218 : : boost::multi_index::ordered_non_unique<boost::multi_index::tag<ByTime>, ByTimeViewExtractor>
219 : : >
220 : : >;
221 : :
222 : : /** Helper type to simplify syntax of iterator types. */
223 : : template<typename Tag>
224 : : using Iter = typename Index::index<Tag>::type::iterator;
225 : :
226 : : /** Per-peer statistics object. */
227 : 4018045 : struct PeerInfo {
228 : : size_t m_total = 0; //!< Total number of announcements for this peer.
229 : : size_t m_completed = 0; //!< Number of COMPLETED announcements for this peer.
230 : : size_t m_requested = 0; //!< Number of REQUESTED announcements for this peer.
231 : : };
232 : :
233 : : /** Per-txhash statistics object. Only used for sanity checking. */
234 : 1944730 : struct TxHashInfo
235 : : {
236 : : //! Number of CANDIDATE_DELAYED announcements for this txhash.
237 : : size_t m_candidate_delayed = 0;
238 : : //! Number of CANDIDATE_READY announcements for this txhash.
239 : : size_t m_candidate_ready = 0;
240 : : //! Number of CANDIDATE_BEST announcements for this txhash (at most one).
241 : : size_t m_candidate_best = 0;
242 : : //! Number of REQUESTED announcements for this txhash (at most one; mutually exclusive with CANDIDATE_BEST).
243 : : size_t m_requested = 0;
244 : : //! The priority of the CANDIDATE_BEST announcement if one exists, or max() otherwise.
245 : : Priority m_priority_candidate_best = std::numeric_limits<Priority>::max();
246 : : //! The highest priority of all CANDIDATE_READY announcements (or min() if none exist).
247 : : Priority m_priority_best_candidate_ready = std::numeric_limits<Priority>::min();
248 : : //! All peers we have an announcement for this txhash for.
249 : : std::vector<NodeId> m_peers;
250 : : };
251 : :
252 : : /** Compare two PeerInfo objects. Only used for sanity checking. */
253 : 4010375 : bool operator==(const PeerInfo& a, const PeerInfo& b)
254 : : {
255 : 4010375 : return std::tie(a.m_total, a.m_completed, a.m_requested) ==
256 : 4010375 : std::tie(b.m_total, b.m_completed, b.m_requested);
257 : : };
258 : :
259 : : /** (Re)compute the PeerInfo map from the index. Only used for sanity checking. */
260 : 41515 : std::unordered_map<NodeId, PeerInfo> RecomputePeerInfo(const Index& index)
261 : : {
262 : 41515 : std::unordered_map<NodeId, PeerInfo> ret;
263 [ + + ]: 4449016 : for (const Announcement& ann : index) {
264 [ + - ]: 4407501 : PeerInfo& info = ret[ann.m_peer];
265 : 4407501 : ++info.m_total;
266 : 4407501 : info.m_requested += (ann.GetState() == State::REQUESTED);
267 : 4407501 : info.m_completed += (ann.GetState() == State::COMPLETED);
268 : : }
269 : 41515 : return ret;
270 : 0 : }
271 : :
272 : : /** Compute the TxHashInfo map. Only used for sanity checking. */
273 : 41515 : std::map<uint256, TxHashInfo> ComputeTxHashInfo(const Index& index, const PriorityComputer& computer)
274 : : {
275 : 41515 : std::map<uint256, TxHashInfo> ret;
276 [ + + ]: 8856517 : for (const Announcement& ann : index) {
277 [ + + - + : 8815002 : TxHashInfo& info = ret[ann.m_gtxid.ToUint256()];
- ]
278 : : // Classify how many announcements of each state we have for this txhash.
279 : 4407501 : info.m_candidate_delayed += (ann.GetState() == State::CANDIDATE_DELAYED);
280 : 4407501 : info.m_candidate_ready += (ann.GetState() == State::CANDIDATE_READY);
281 : 4407501 : info.m_candidate_best += (ann.GetState() == State::CANDIDATE_BEST);
282 : 4407501 : info.m_requested += (ann.GetState() == State::REQUESTED);
283 : : // And track the priority of the best CANDIDATE_READY/CANDIDATE_BEST announcements.
284 [ + + ]: 4407501 : if (ann.GetState() == State::CANDIDATE_BEST) {
285 [ + - ]: 1261956 : info.m_priority_candidate_best = computer(ann);
286 : : }
287 [ + + ]: 4407501 : if (ann.GetState() == State::CANDIDATE_READY) {
288 [ + - + + ]: 1386242 : info.m_priority_best_candidate_ready = std::max(info.m_priority_best_candidate_ready, computer(ann));
289 : : }
290 : : // Also keep track of which peers this txhash has an announcement for (so we can detect duplicates).
291 [ + - ]: 4407501 : info.m_peers.push_back(ann.m_peer);
292 : : }
293 : 41515 : return ret;
294 : 0 : }
295 : :
296 : : } // namespace
297 : :
298 : : /** Actual implementation for TxRequestTracker's data structure. */
299 : 1280 : class TxRequestTracker::Impl {
300 : : //! The current sequence number. Increases for every announcement. This is used to sort txhashes returned by
301 : : //! GetRequestable in announcement order.
302 : : SequenceNumber m_current_sequence{0};
303 : :
304 : : //! This tracker's priority computer.
305 : : const PriorityComputer m_computer;
306 : :
307 : : //! This tracker's main data structure. See SanityCheck() for the invariants that apply to it.
308 : : Index m_index;
309 : :
310 : : //! Map with this tracker's per-peer statistics.
311 : : std::unordered_map<NodeId, PeerInfo> m_peerinfo;
312 : :
313 : : public:
314 : 41515 : void SanityCheck() const
315 : : {
316 : : // Recompute m_peerdata from m_index. This verifies the data in it as it should just be caching statistics
317 : : // on m_index. It also verifies the invariant that no PeerInfo announcements with m_total==0 exist.
318 [ - + ]: 41515 : assert(m_peerinfo == RecomputePeerInfo(m_index));
319 : :
320 : : // Calculate per-txhash statistics from m_index, and validate invariants.
321 [ + + ]: 1986245 : for (auto& item : ComputeTxHashInfo(m_index, m_computer)) {
322 : 1944730 : TxHashInfo& info = item.second;
323 : :
324 : : // Cannot have only COMPLETED peer (txhash should have been forgotten already)
325 [ - + ]: 1944730 : assert(info.m_candidate_delayed + info.m_candidate_ready + info.m_candidate_best + info.m_requested > 0);
326 : :
327 : : // Can have at most 1 CANDIDATE_BEST/REQUESTED peer
328 [ - + ]: 1944730 : assert(info.m_candidate_best + info.m_requested <= 1);
329 : :
330 : : // If there are any CANDIDATE_READY announcements, there must be exactly one CANDIDATE_BEST or REQUESTED
331 : : // announcement.
332 [ + + ]: 1944730 : if (info.m_candidate_ready > 0) {
333 [ - + ]: 596459 : assert(info.m_candidate_best + info.m_requested == 1);
334 : : }
335 : :
336 : : // If there is both a CANDIDATE_READY and a CANDIDATE_BEST announcement, the CANDIDATE_BEST one must be
337 : : // at least as good (equal or higher priority) as the best CANDIDATE_READY.
338 [ + + + + ]: 1944730 : if (info.m_candidate_ready && info.m_candidate_best) {
339 [ - + ]: 339495 : assert(info.m_priority_candidate_best >= info.m_priority_best_candidate_ready);
340 : : }
341 : :
342 : : // No txhash can have been announced by the same peer twice.
343 : 1944730 : std::sort(info.m_peers.begin(), info.m_peers.end());
344 [ - + ]: 1944730 : assert(std::adjacent_find(info.m_peers.begin(), info.m_peers.end()) == info.m_peers.end());
345 : 41515 : }
346 : 41515 : }
347 : :
348 : 29355 : void PostGetRequestableSanityCheck(std::chrono::microseconds now) const
349 : : {
350 [ + + ]: 3150762 : for (const Announcement& ann : m_index) {
351 [ + + ]: 3121407 : if (ann.IsWaiting()) {
352 : : // REQUESTED and CANDIDATE_DELAYED must have a time in the future (they should have been converted
353 : : // to COMPLETED/CANDIDATE_READY respectively).
354 [ - + ]: 1198453 : assert(ann.m_time > now);
355 [ + + ]: 5044361 : } else if (ann.IsSelectable()) {
356 : : // CANDIDATE_READY and CANDIDATE_BEST cannot have a time in the future (they should have remained
357 : : // CANDIDATE_DELAYED, or should have been converted back to it if time went backwards).
358 [ - + ]: 1658887 : assert(ann.m_time <= now);
359 : : }
360 : : }
361 : 29355 : }
362 : :
363 : : private:
364 : : //! Wrapper around Index::...::erase that keeps m_peerinfo up to date.
365 : : template<typename Tag>
366 : 31411 : Iter<Tag> Erase(Iter<Tag> it)
367 : : {
368 [ + + ]: 31411 : auto peerit = m_peerinfo.find(it->m_peer);
369 [ + + ]: 31411 : peerit->second.m_completed -= it->GetState() == State::COMPLETED;
370 : 31411 : peerit->second.m_requested -= it->GetState() == State::REQUESTED;
371 [ + + ]: 31411 : if (--peerit->second.m_total == 0) m_peerinfo.erase(peerit);
372 : 31411 : return m_index.get<Tag>().erase(it);
373 : : }
374 : :
375 : : //! Wrapper around Index::...::modify that keeps m_peerinfo up to date.
376 : : template<typename Tag, typename Modifier>
377 : 94767 : void Modify(Iter<Tag> it, Modifier modifier)
378 : : {
379 : 94767 : auto peerit = m_peerinfo.find(it->m_peer);
380 : 94767 : peerit->second.m_completed -= it->GetState() == State::COMPLETED;
381 : 94767 : peerit->second.m_requested -= it->GetState() == State::REQUESTED;
382 : 94767 : m_index.get<Tag>().modify(it, std::move(modifier));
383 : 94767 : peerit->second.m_completed += it->GetState() == State::COMPLETED;
384 : 94767 : peerit->second.m_requested += it->GetState() == State::REQUESTED;
385 : 94767 : }
386 : :
387 : : //! Convert a CANDIDATE_DELAYED announcement into a CANDIDATE_READY. If this makes it the new best
388 : : //! CANDIDATE_READY (and no REQUESTED exists) and better than the CANDIDATE_BEST (if any), it becomes the new
389 : : //! CANDIDATE_BEST.
390 : 30888 : void PromoteCandidateReady(Iter<ByTxHash> it)
391 : : {
392 [ - + ]: 30888 : assert(it != m_index.get<ByTxHash>().end());
393 [ - + ]: 30888 : assert(it->GetState() == State::CANDIDATE_DELAYED);
394 : : // Convert CANDIDATE_DELAYED to CANDIDATE_READY first.
395 [ + - ]: 61776 : Modify<ByTxHash>(it, [](Announcement& ann){ ann.SetState(State::CANDIDATE_READY); });
396 : : // The following code relies on the fact that the ByTxHash is sorted by txhash, and then by state (first
397 : : // _DELAYED, then _READY, then _BEST/REQUESTED). Within the _READY announcements, the best one (highest
398 : : // priority) comes last. Thus, if an existing _BEST exists for the same txhash that this announcement may
399 : : // be preferred over, it must immediately follow the newly created _READY.
400 : 30888 : auto it_next = std::next(it);
401 [ + + + + : 86020 : if (it_next == m_index.get<ByTxHash>().end() || it_next->m_gtxid.ToUint256() != it->m_gtxid.ToUint256() ||
- + + - +
+ ]
402 [ - + ]: 5148 : it_next->GetState() == State::COMPLETED) {
403 : : // This is the new best CANDIDATE_READY, and there is no IsSelected() announcement for this txhash
404 : : // already.
405 [ + - ]: 51480 : Modify<ByTxHash>(it, [](Announcement& ann){ ann.SetState(State::CANDIDATE_BEST); });
406 [ + + ]: 5148 : } else if (it_next->GetState() == State::CANDIDATE_BEST) {
407 : 2091 : Priority priority_old = m_computer(*it_next);
408 : 2091 : Priority priority_new = m_computer(*it);
409 [ + + ]: 2091 : if (priority_new > priority_old) {
410 : : // There is a CANDIDATE_BEST announcement already, but this one is better.
411 [ + - ]: 2872 : Modify<ByTxHash>(it_next, [](Announcement& ann){ ann.SetState(State::CANDIDATE_READY); });
412 [ + - ]: 2872 : Modify<ByTxHash>(it, [](Announcement& ann){ ann.SetState(State::CANDIDATE_BEST); });
413 : : }
414 : : }
415 : 30888 : }
416 : :
417 : : //! Change the state of an announcement to something non-IsSelected(). If it was IsSelected(), the next best
418 : : //! announcement will be marked CANDIDATE_BEST.
419 : 5437 : void ChangeAndReselect(Iter<ByTxHash> it, State new_state)
420 : : {
421 [ - + ]: 5437 : assert(new_state == State::COMPLETED || new_state == State::CANDIDATE_DELAYED);
422 [ - + ]: 5437 : assert(it != m_index.get<ByTxHash>().end());
423 [ + + + + ]: 9260 : if (it->IsSelected() && it != m_index.get<ByTxHash>().begin()) {
424 : 4620 : auto it_prev = std::prev(it);
425 : : // The next best CANDIDATE_READY, if any, immediately precedes the REQUESTED or CANDIDATE_BEST
426 : : // announcement in the ByTxHash index.
427 [ + + - + : 13860 : if (it_prev->m_gtxid.ToUint256() == it->m_gtxid.ToUint256() && it_prev->GetState() == State::CANDIDATE_READY) {
+ - + + +
+ ]
428 : : // If one such CANDIDATE_READY exists (for this txhash), convert it to CANDIDATE_BEST.
429 [ + - ]: 8624 : Modify<ByTxHash>(it_prev, [](Announcement& ann){ ann.SetState(State::CANDIDATE_BEST); });
430 : : }
431 : : }
432 [ + - ]: 10874 : Modify<ByTxHash>(it, [new_state](Announcement& ann){ ann.SetState(new_state); });
433 : 5437 : }
434 : :
435 : : //! Check if 'it' is the only announcement for a given txhash that isn't COMPLETED.
436 : 27794 : bool IsOnlyNonCompleted(Iter<ByTxHash> it)
437 : : {
438 [ - + ]: 27794 : assert(it != m_index.get<ByTxHash>().end());
439 [ - + ]: 27794 : assert(it->GetState() != State::COMPLETED); // Not allowed to call this on COMPLETED announcements.
440 : :
441 : : // This announcement has a predecessor that belongs to the same txhash. Due to ordering, and the
442 : : // fact that 'it' is not COMPLETED, its predecessor cannot be COMPLETED here.
443 [ + + + + : 54836 : if (it != m_index.get<ByTxHash>().begin() && std::prev(it)->m_gtxid.ToUint256() == it->m_gtxid.ToUint256()) return false;
- + + - +
+ ]
444 : :
445 : : // This announcement has a successor that belongs to the same txhash, and is not COMPLETED.
446 [ + + + + : 105445 : if (std::next(it) != m_index.get<ByTxHash>().end() && std::next(it)->m_gtxid.ToUint256() == it->m_gtxid.ToUint256() &&
- + + - +
+ + + ]
447 [ + + ]: 1703 : std::next(it)->GetState() != State::COMPLETED) return false;
448 : :
449 : : return true;
450 : : }
451 : :
452 : : /** Convert any announcement to a COMPLETED one. If there are no non-COMPLETED announcements left for this
453 : : * txhash, they are deleted. If this was a REQUESTED announcement, and there are other CANDIDATEs left, the
454 : : * best one is made CANDIDATE_BEST. Returns whether the announcement still exists. */
455 : 27799 : bool MakeCompleted(Iter<ByTxHash> it)
456 : : {
457 [ - + ]: 27799 : assert(it != m_index.get<ByTxHash>().end());
458 : :
459 : : // Nothing to be done if it's already COMPLETED.
460 [ + + ]: 27799 : if (it->GetState() == State::COMPLETED) return true;
461 : :
462 [ + + ]: 27794 : if (IsOnlyNonCompleted(it)) {
463 : : // This is the last non-COMPLETED announcement for this txhash. Delete all.
464 [ + + - ]: 45354 : uint256 txhash = it->m_gtxid.ToUint256();
465 : 24359 : do {
466 : 24359 : it = Erase<ByTxHash>(it);
467 [ + + + + : 63727 : } while (it != m_index.get<ByTxHash>().end() && it->m_gtxid.ToUint256() == txhash);
- + + +
+ ]
468 : : return false;
469 : : }
470 : :
471 : : // Mark the announcement COMPLETED, and select the next best announcement (the first CANDIDATE_READY) if
472 : : // needed.
473 : 5117 : ChangeAndReselect(it, State::COMPLETED);
474 : :
475 : 5117 : return true;
476 : : }
477 : :
478 : : //! Make the data structure consistent with a given point in time:
479 : : //! - REQUESTED announcements with expiry <= now are turned into COMPLETED.
480 : : //! - CANDIDATE_DELAYED announcements with reqtime <= now are turned into CANDIDATE_{READY,BEST}.
481 : : //! - CANDIDATE_{READY,BEST} announcements with reqtime > now are turned into CANDIDATE_DELAYED.
482 : 446232 : void SetTimePoint(std::chrono::microseconds now, std::vector<std::pair<NodeId, GenTxid>>* expired)
483 : : {
484 [ + - - + ]: 446232 : if (expired) expired->clear();
485 : :
486 : : // Iterate over all CANDIDATE_DELAYED and REQUESTED from old to new, as long as they're in the past,
487 : : // and convert them to CANDIDATE_READY and COMPLETED respectively.
488 [ + + ]: 478190 : while (!m_index.empty()) {
489 : 130096 : auto it = m_index.get<ByTime>().begin();
490 [ + + + + ]: 130096 : if (it->GetState() == State::CANDIDATE_DELAYED && it->m_time <= now) {
491 : 30888 : PromoteCandidateReady(m_index.project<ByTxHash>(it));
492 [ + + + + ]: 99208 : } else if (it->GetState() == State::REQUESTED && it->m_time <= now) {
493 [ + - ]: 1070 : if (expired) expired->emplace_back(it->m_peer, it->m_gtxid);
494 : 1070 : MakeCompleted(m_index.project<ByTxHash>(it));
495 : : } else {
496 : : break;
497 : : }
498 : : }
499 : :
500 [ + + ]: 446552 : while (!m_index.empty()) {
501 : : // If time went backwards, we may need to demote CANDIDATE_BEST and CANDIDATE_READY announcements back
502 : : // to CANDIDATE_DELAYED. This is an unusual edge case, and unlikely to matter in production. However,
503 : : // it makes it much easier to specify and test TxRequestTracker::Impl's behaviour.
504 : 98458 : auto it = std::prev(m_index.get<ByTime>().end());
505 [ + + + + ]: 131145 : if (it->IsSelectable() && it->m_time > now) {
506 : 320 : ChangeAndReselect(m_index.project<ByTxHash>(it), State::CANDIDATE_DELAYED);
507 : : } else {
508 : : break;
509 : : }
510 : : }
511 : 446232 : }
512 : :
513 : : public:
514 : 1280 : explicit Impl(bool deterministic) :
515 : 1280 : m_computer(deterministic),
516 : : // Explicitly initialize m_index as we need to pass a reference to m_computer to ByTxHashViewExtractor.
517 : 1280 : m_index(boost::make_tuple(
518 : 1280 : boost::make_tuple(ByPeerViewExtractor(), std::less<ByPeerView>()),
519 : 1280 : boost::make_tuple(ByTxHashViewExtractor(m_computer), std::less<ByTxHashView>()),
520 : 1280 : boost::make_tuple(ByTimeViewExtractor(), std::less<ByTimeView>())
521 : 1280 : )) {}
522 : :
523 : : // Disable copying and assigning (a default copy won't work due the stateful ByTxHashViewExtractor).
524 : : Impl(const Impl&) = delete;
525 : : Impl& operator=(const Impl&) = delete;
526 : :
527 : 3967 : void DisconnectedPeer(NodeId peer)
528 : : {
529 : 3967 : auto& index = m_index.get<ByPeer>();
530 : 3967 : auto it = index.lower_bound(ByPeerView{peer, false, uint256::ZERO});
531 [ + + + + ]: 21440 : while (it != index.end() && it->m_peer == peer) {
532 : : // Check what to continue with after this iteration. 'it' will be deleted in what follows, so we need to
533 : : // decide what to continue with afterwards. There are a number of cases to consider:
534 : : // - std::next(it) is end() or belongs to a different peer. In that case, this is the last iteration
535 : : // of the loop (denote this by setting it_next to end()).
536 : : // - 'it' is not the only non-COMPLETED announcement for its txhash. This means it will be deleted, but
537 : : // no other Announcement objects will be modified. Continue with std::next(it) if it belongs to the
538 : : // same peer, but decide this ahead of time (as 'it' may change position in what follows).
539 : : // - 'it' is the only non-COMPLETED announcement for its txhash. This means it will be deleted along
540 : : // with all other announcements for the same txhash - which may include std::next(it). However, other
541 : : // than 'it', no announcements for the same peer can be affected (due to (peer, txhash) uniqueness).
542 : : // In other words, the situation where std::next(it) is deleted can only occur if std::next(it)
543 : : // belongs to a different peer but the same txhash as 'it'. This is covered by the first bulletpoint
544 : : // already, and we'll have set it_next to end().
545 [ + + + + ]: 40442 : auto it_next = (std::next(it) == index.end() || std::next(it)->m_peer != peer) ? index.end() :
546 : 11166 : std::next(it);
547 : : // If the announcement isn't already COMPLETED, first make it COMPLETED (which will mark other
548 : : // CANDIDATEs as CANDIDATE_BEST, or delete all of a txhash's announcements if no non-COMPLETED ones are
549 : : // left).
550 [ + + ]: 13506 : if (MakeCompleted(m_index.project<ByTxHash>(it))) {
551 : : // Then actually delete the announcement (unless it was already deleted by MakeCompleted).
552 : 751 : Erase<ByPeer>(it);
553 : : }
554 : 13506 : it = it_next;
555 : : }
556 : 3967 : }
557 : :
558 : 332148 : void ForgetTxHash(const uint256& txhash)
559 : : {
560 : 332148 : auto it = m_index.get<ByTxHash>().lower_bound(ByTxHashView{txhash, State::CANDIDATE_DELAYED, 0});
561 [ + + + + : 696040 : while (it != m_index.get<ByTxHash>().end() && it->m_gtxid.ToUint256() == txhash) {
- + + ]
562 : 6301 : it = Erase<ByTxHash>(it);
563 : : }
564 : 332148 : }
565 : :
566 : 1059 : void GetCandidatePeers(const uint256& txhash, std::vector<NodeId>& result_peers) const
567 : : {
568 : 1059 : auto it = m_index.get<ByTxHash>().lower_bound(ByTxHashView{txhash, State::CANDIDATE_DELAYED, 0});
569 [ + + + + : 2850 : while (it != m_index.get<ByTxHash>().end() && it->m_gtxid.ToUint256() == txhash && it->GetState() != State::COMPLETED) {
- + + +
+ ]
570 : 4 : result_peers.push_back(it->m_peer);
571 : 4 : ++it;
572 : : }
573 : 1059 : }
574 : :
575 : 31501 : void ReceivedInv(NodeId peer, const GenTxid& gtxid, bool preferred,
576 : : std::chrono::microseconds reqtime)
577 : : {
578 : : // Bail out if we already have a CANDIDATE_BEST announcement for this (txhash, peer) combination. The case
579 : : // where there is a non-CANDIDATE_BEST announcement already will be caught by the uniqueness property of the
580 : : // ByPeer index when we try to emplace the new object below.
581 [ + + - + : 63002 : if (m_index.get<ByPeer>().count(ByPeerView{peer, true, gtxid.ToUint256()})) return;
- ]
582 : :
583 : : // Try creating the announcement with CANDIDATE_DELAYED state (which will fail due to the uniqueness
584 : : // of the ByPeer index if a non-CANDIDATE_BEST announcement already exists with the same txhash and peer).
585 : : // Bail out in that case.
586 : 31501 : auto ret = m_index.get<ByPeer>().emplace(gtxid, peer, preferred, reqtime, m_current_sequence);
587 [ + + ]: 31501 : if (!ret.second) return;
588 : :
589 : : // Update accounting metadata.
590 : 31471 : ++m_peerinfo[peer].m_total;
591 : 31471 : ++m_current_sequence;
592 : : }
593 : :
594 : : //! Find the GenTxids to request now from peer.
595 : 446232 : std::vector<GenTxid> GetRequestable(NodeId peer, std::chrono::microseconds now,
596 : : std::vector<std::pair<NodeId, GenTxid>>* expired)
597 : : {
598 : : // Move time.
599 : 446232 : SetTimePoint(now, expired);
600 : :
601 : : // Find all CANDIDATE_BEST announcements for this peer.
602 : 446232 : std::vector<const Announcement*> selected;
603 : 446232 : auto it_peer = m_index.get<ByPeer>().lower_bound(ByPeerView{peer, true, uint256::ZERO});
604 [ + + + + ]: 482057 : while (it_peer != m_index.get<ByPeer>().end() && it_peer->m_peer == peer &&
605 [ + - ]: 35825 : it_peer->GetState() == State::CANDIDATE_BEST) {
606 [ + - ]: 35825 : selected.emplace_back(&*it_peer);
607 : 35825 : ++it_peer;
608 : : }
609 : :
610 : : // Sort by sequence number.
611 : 446232 : std::sort(selected.begin(), selected.end(), [](const Announcement* a, const Announcement* b) {
612 [ + + + + : 186253 : return a->m_sequence < b->m_sequence;
+ + + + +
+ + + + +
+ + + + +
+ - - +
+ ]
613 : : });
614 : :
615 : : // Convert to GenTxid and return.
616 : 446232 : std::vector<GenTxid> ret;
617 [ - + + - ]: 446232 : ret.reserve(selected.size());
618 [ + - ]: 446232 : std::transform(selected.begin(), selected.end(), std::back_inserter(ret), [](const Announcement* ann) {
619 : 35825 : return ann->m_gtxid;
620 : : });
621 : 446232 : return ret;
622 : 446232 : }
623 : :
624 : 25518 : void RequestedTx(NodeId peer, const uint256& txhash, std::chrono::microseconds expiry)
625 : : {
626 : 25518 : auto it = m_index.get<ByPeer>().find(ByPeerView{peer, true, txhash});
627 [ + + ]: 25518 : if (it == m_index.get<ByPeer>().end()) {
628 : : // There is no CANDIDATE_BEST announcement, look for a _READY or _DELAYED instead. If the caller only
629 : : // ever invokes RequestedTx with the values returned by GetRequestable, and no other non-const functions
630 : : // other than ForgetTxHash and GetRequestable in between, this branch will never execute (as txhashes
631 : : // returned by GetRequestable always correspond to CANDIDATE_BEST announcements).
632 : :
633 : 1920 : it = m_index.get<ByPeer>().find(ByPeerView{peer, false, txhash});
634 [ + + + + ]: 1920 : if (it == m_index.get<ByPeer>().end() || (it->GetState() != State::CANDIDATE_DELAYED &&
635 [ + + ]: 1280 : it->GetState() != State::CANDIDATE_READY)) {
636 : : // There is no CANDIDATE announcement tracked for this peer, so we have nothing to do. Either this
637 : : // txhash wasn't tracked at all (and the caller should have called ReceivedInv), or it was already
638 : : // requested and/or completed for other reasons and this is just a superfluous RequestedTx call.
639 : : return;
640 : : }
641 : :
642 : : // Look for an existing CANDIDATE_BEST or REQUESTED with the same txhash. We only need to do this if the
643 : : // found announcement had a different state than CANDIDATE_BEST. If it did, invariants guarantee that no
644 : : // other CANDIDATE_BEST or REQUESTED can exist.
645 : 960 : auto it_old = m_index.get<ByTxHash>().lower_bound(ByTxHashView{txhash, State::CANDIDATE_BEST, 0});
646 [ + - + + : 1920 : if (it_old != m_index.get<ByTxHash>().end() && it_old->m_gtxid.ToUint256() == txhash) {
- + - ]
647 [ + + ]: 960 : if (it_old->GetState() == State::CANDIDATE_BEST) {
648 : : // The data structure's invariants require that there can be at most one CANDIDATE_BEST or one
649 : : // REQUESTED announcement per txhash (but not both simultaneously), so we have to convert any
650 : : // existing CANDIDATE_BEST to another CANDIDATE_* when constructing another REQUESTED.
651 : : // It doesn't matter whether we pick CANDIDATE_READY or _DELAYED here, as SetTimePoint()
652 : : // will correct it at GetRequestable() time. If time only goes forward, it will always be
653 : : // _READY, so pick that to avoid extra work in SetTimePoint().
654 [ + - ]: 1280 : Modify<ByTxHash>(it_old, [](Announcement& ann) { ann.SetState(State::CANDIDATE_READY); });
655 [ + - ]: 320 : } else if (it_old->GetState() == State::REQUESTED) {
656 : : // As we're no longer waiting for a response to the previous REQUESTED announcement, convert it
657 : : // to COMPLETED. This also helps guaranteeing progress.
658 [ + - ]: 640 : Modify<ByTxHash>(it_old, [](Announcement& ann) { ann.SetState(State::COMPLETED); });
659 : : }
660 : : }
661 : : }
662 : :
663 : 24558 : Modify<ByPeer>(it, [expiry](Announcement& ann) {
664 : 24558 : ann.SetState(State::REQUESTED);
665 [ + - ]: 24558 : ann.m_time = expiry;
666 : : });
667 : : }
668 : :
669 : 32353 : void ReceivedResponse(NodeId peer, const uint256& txhash)
670 : : {
671 : : // We need to search the ByPeer index for both (peer, false, txhash) and (peer, true, txhash).
672 : 32353 : auto it = m_index.get<ByPeer>().find(ByPeerView{peer, false, txhash});
673 [ + + ]: 32353 : if (it == m_index.get<ByPeer>().end()) {
674 : 19527 : it = m_index.get<ByPeer>().find(ByPeerView{peer, true, txhash});
675 : : }
676 [ + + ]: 32353 : if (it != m_index.get<ByPeer>().end()) MakeCompleted(m_index.project<ByTxHash>(it));
677 : 32353 : }
678 : :
679 : 50235 : size_t CountInFlight(NodeId peer) const
680 : : {
681 : 50235 : auto it = m_peerinfo.find(peer);
682 [ + + ]: 50235 : if (it != m_peerinfo.end()) return it->second.m_requested;
683 : : return 0;
684 : : }
685 : :
686 : 29355 : size_t CountCandidates(NodeId peer) const
687 : : {
688 : 29355 : auto it = m_peerinfo.find(peer);
689 [ + + ]: 29355 : if (it != m_peerinfo.end()) return it->second.m_total - it->second.m_requested - it->second.m_completed;
690 : : return 0;
691 : : }
692 : :
693 : 51947 : size_t Count(NodeId peer) const
694 : : {
695 : 51947 : auto it = m_peerinfo.find(peer);
696 [ + + ]: 51947 : if (it != m_peerinfo.end()) return it->second.m_total;
697 : : return 0;
698 : : }
699 : :
700 : : //! Count how many announcements are being tracked in total across all peers and transactions.
701 : 891 : size_t Size() const { return m_index.size(); }
702 : :
703 : 1856224 : uint64_t ComputePriority(const uint256& txhash, NodeId peer, bool preferred) const
704 : : {
705 : : // Return Priority as a uint64_t as Priority is internal.
706 : 1856224 : return uint64_t{m_computer(txhash, peer, preferred)};
707 : : }
708 : :
709 : : };
710 : :
711 : 1280 : TxRequestTracker::TxRequestTracker(bool deterministic) :
712 : 1280 : m_impl{std::make_unique<TxRequestTracker::Impl>(deterministic)} {}
713 : :
714 : 1280 : TxRequestTracker::~TxRequestTracker() = default;
715 : :
716 : 332148 : void TxRequestTracker::ForgetTxHash(const uint256& txhash) { m_impl->ForgetTxHash(txhash); }
717 : 3967 : void TxRequestTracker::DisconnectedPeer(NodeId peer) { m_impl->DisconnectedPeer(peer); }
718 : 50235 : size_t TxRequestTracker::CountInFlight(NodeId peer) const { return m_impl->CountInFlight(peer); }
719 : 29355 : size_t TxRequestTracker::CountCandidates(NodeId peer) const { return m_impl->CountCandidates(peer); }
720 : 51947 : size_t TxRequestTracker::Count(NodeId peer) const { return m_impl->Count(peer); }
721 : 891 : size_t TxRequestTracker::Size() const { return m_impl->Size(); }
722 : 1059 : void TxRequestTracker::GetCandidatePeers(const uint256& txhash, std::vector<NodeId>& result_peers) const { return m_impl->GetCandidatePeers(txhash, result_peers); }
723 : 41515 : void TxRequestTracker::SanityCheck() const { m_impl->SanityCheck(); }
724 : :
725 : 29355 : void TxRequestTracker::PostGetRequestableSanityCheck(std::chrono::microseconds now) const
726 : : {
727 : 29355 : m_impl->PostGetRequestableSanityCheck(now);
728 : 29355 : }
729 : :
730 : 31501 : void TxRequestTracker::ReceivedInv(NodeId peer, const GenTxid& gtxid, bool preferred,
731 : : std::chrono::microseconds reqtime)
732 : : {
733 : 31501 : m_impl->ReceivedInv(peer, gtxid, preferred, reqtime);
734 : 31501 : }
735 : :
736 : 25518 : void TxRequestTracker::RequestedTx(NodeId peer, const uint256& txhash, std::chrono::microseconds expiry)
737 : : {
738 : 25518 : m_impl->RequestedTx(peer, txhash, expiry);
739 : 25518 : }
740 : :
741 : 32353 : void TxRequestTracker::ReceivedResponse(NodeId peer, const uint256& txhash)
742 : : {
743 : 32353 : m_impl->ReceivedResponse(peer, txhash);
744 : 32353 : }
745 : :
746 : 446232 : std::vector<GenTxid> TxRequestTracker::GetRequestable(NodeId peer, std::chrono::microseconds now,
747 : : std::vector<std::pair<NodeId, GenTxid>>* expired)
748 : : {
749 : 446232 : return m_impl->GetRequestable(peer, now, expired);
750 : : }
751 : :
752 : 1856224 : uint64_t TxRequestTracker::ComputePriority(const uint256& txhash, NodeId peer, bool preferred) const
753 : : {
754 : 1856224 : return m_impl->ComputePriority(txhash, peer, preferred);
755 : : }
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