Bitcoin Core  24.99.0
P2P Digital Currency
packages.cpp
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1 // Copyright (c) 2021-2022 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 <policy/packages.h>
6 #include <policy/policy.h>
8 #include <uint256.h>
9 #include <util/hasher.h>
10 
11 #include <algorithm>
12 #include <cassert>
13 #include <iterator>
14 #include <memory>
15 #include <numeric>
16 #include <unordered_set>
17 
18 bool CheckPackage(const Package& txns, PackageValidationState& state)
19 {
20  const unsigned int package_count = txns.size();
21 
22  if (package_count > MAX_PACKAGE_COUNT) {
23  return state.Invalid(PackageValidationResult::PCKG_POLICY, "package-too-many-transactions");
24  }
25 
26  const int64_t total_size = std::accumulate(txns.cbegin(), txns.cend(), 0,
27  [](int64_t sum, const auto& tx) { return sum + GetVirtualTransactionSize(*tx); });
28  // If the package only contains 1 tx, it's better to report the policy violation on individual tx size.
29  if (package_count > 1 && total_size > MAX_PACKAGE_SIZE * 1000) {
30  return state.Invalid(PackageValidationResult::PCKG_POLICY, "package-too-large");
31  }
32 
33  // Require the package to be sorted in order of dependency, i.e. parents appear before children.
34  // An unsorted package will fail anyway on missing-inputs, but it's better to quit earlier and
35  // fail on something less ambiguous (missing-inputs could also be an orphan or trying to
36  // spend nonexistent coins).
37  std::unordered_set<uint256, SaltedTxidHasher> later_txids;
38  std::transform(txns.cbegin(), txns.cend(), std::inserter(later_txids, later_txids.end()),
39  [](const auto& tx) { return tx->GetHash(); });
40  for (const auto& tx : txns) {
41  for (const auto& input : tx->vin) {
42  if (later_txids.find(input.prevout.hash) != later_txids.end()) {
43  // The parent is a subsequent transaction in the package.
44  return state.Invalid(PackageValidationResult::PCKG_POLICY, "package-not-sorted");
45  }
46  }
47  later_txids.erase(tx->GetHash());
48  }
49 
50  // Don't allow any conflicting transactions, i.e. spending the same inputs, in a package.
51  std::unordered_set<COutPoint, SaltedOutpointHasher> inputs_seen;
52  for (const auto& tx : txns) {
53  for (const auto& input : tx->vin) {
54  if (inputs_seen.find(input.prevout) != inputs_seen.end()) {
55  // This input is also present in another tx in the package.
56  return state.Invalid(PackageValidationResult::PCKG_POLICY, "conflict-in-package");
57  }
58  }
59  // Batch-add all the inputs for a tx at a time. If we added them 1 at a time, we could
60  // catch duplicate inputs within a single tx. This is a more severe, consensus error,
61  // and we want to report that from CheckTransaction instead.
62  std::transform(tx->vin.cbegin(), tx->vin.cend(), std::inserter(inputs_seen, inputs_seen.end()),
63  [](const auto& input) { return input.prevout; });
64  }
65  return true;
66 }
67 
68 bool IsChildWithParents(const Package& package)
69 {
70  assert(std::all_of(package.cbegin(), package.cend(), [](const auto& tx){return tx != nullptr;}));
71  if (package.size() < 2) return false;
72 
73  // The package is expected to be sorted, so the last transaction is the child.
74  const auto& child = package.back();
75  std::unordered_set<uint256, SaltedTxidHasher> input_txids;
76  std::transform(child->vin.cbegin(), child->vin.cend(),
77  std::inserter(input_txids, input_txids.end()),
78  [](const auto& input) { return input.prevout.hash; });
79 
80  // Every transaction must be a parent of the last transaction in the package.
81  return std::all_of(package.cbegin(), package.cend() - 1,
82  [&input_txids](const auto& ptx) { return input_txids.count(ptx->GetHash()) > 0; });
83 }
bool Invalid(Result result, const std::string &reject_reason="", const std::string &debug_message="")
Definition: validation.h:104
volatile double sum
Definition: examples.cpp:10
bool IsChildWithParents(const Package &package)
Context-free check that a package is exactly one child and its parents; not all parents need to be pr...
Definition: packages.cpp:68
bool CheckPackage(const Package &txns, PackageValidationState &state)
Context-free package policy checks:
Definition: packages.cpp:18
std::vector< CTransactionRef > Package
A package is an ordered list of transactions.
Definition: packages.h:44
static constexpr uint32_t MAX_PACKAGE_COUNT
Default maximum number of transactions in a package.
Definition: packages.h:17
static constexpr uint32_t MAX_PACKAGE_SIZE
Default maximum total virtual size of transactions in a package in KvB.
Definition: packages.h:19
@ PCKG_POLICY
The package itself is invalid (e.g. too many transactions).
assert(!tx.IsCoinBase())