diff options
Diffstat (limited to 'src/policy')
| -rw-r--r-- | src/policy/packages.cpp | 62 | ||||
| -rw-r--r-- | src/policy/packages.h | 10 |
2 files changed, 72 insertions, 0 deletions
diff --git a/src/policy/packages.cpp b/src/policy/packages.cpp new file mode 100644 index 0000000000..cfd0539965 --- /dev/null +++ b/src/policy/packages.cpp @@ -0,0 +1,62 @@ +// Copyright (c) 2021 The Bitcoin Core developers +// Distributed under the MIT software license, see the accompanying +// file COPYING or http://www.opensource.org/licenses/mit-license.php. + +#include <consensus/validation.h> +#include <policy/packages.h> +#include <primitives/transaction.h> +#include <uint256.h> +#include <util/hasher.h> + +#include <numeric> +#include <unordered_set> + +bool CheckPackage(const Package& txns, PackageValidationState& state) +{ + const unsigned int package_count = txns.size(); + + if (package_count > MAX_PACKAGE_COUNT) { + return state.Invalid(PackageValidationResult::PCKG_POLICY, "package-too-many-transactions"); + } + + const int64_t total_size = std::accumulate(txns.cbegin(), txns.cend(), 0, + [](int64_t sum, const auto& tx) { return sum + GetVirtualTransactionSize(*tx); }); + // If the package only contains 1 tx, it's better to report the policy violation on individual tx size. + if (package_count > 1 && total_size > MAX_PACKAGE_SIZE * 1000) { + return state.Invalid(PackageValidationResult::PCKG_POLICY, "package-too-large"); + } + + // Require the package to be sorted in order of dependency, i.e. parents appear before children. + // An unsorted package will fail anyway on missing-inputs, but it's better to quit earlier and + // fail on something less ambiguous (missing-inputs could also be an orphan or trying to + // spend nonexistent coins). + std::unordered_set<uint256, SaltedTxidHasher> later_txids; + std::transform(txns.cbegin(), txns.cend(), std::inserter(later_txids, later_txids.end()), + [](const auto& tx) { return tx->GetHash(); }); + for (const auto& tx : txns) { + for (const auto& input : tx->vin) { + if (later_txids.find(input.prevout.hash) != later_txids.end()) { + // The parent is a subsequent transaction in the package. + return state.Invalid(PackageValidationResult::PCKG_POLICY, "package-not-sorted"); + } + } + later_txids.erase(tx->GetHash()); + } + + // Don't allow any conflicting transactions, i.e. spending the same inputs, in a package. + std::unordered_set<COutPoint, SaltedOutpointHasher> inputs_seen; + for (const auto& tx : txns) { + for (const auto& input : tx->vin) { + if (inputs_seen.find(input.prevout) != inputs_seen.end()) { + // This input is also present in another tx in the package. + return state.Invalid(PackageValidationResult::PCKG_POLICY, "conflict-in-package"); + } + } + // Batch-add all the inputs for a tx at a time. If we added them 1 at a time, we could + // catch duplicate inputs within a single tx. This is a more severe, consensus error, + // and we want to report that from CheckTransaction instead. + std::transform(tx->vin.cbegin(), tx->vin.cend(), std::inserter(inputs_seen, inputs_seen.end()), + [](const auto& input) { return input.prevout; }); + } + return true; +} diff --git a/src/policy/packages.h b/src/policy/packages.h index 4b1463dcb3..6b7ac3e450 100644 --- a/src/policy/packages.h +++ b/src/policy/packages.h @@ -6,6 +6,7 @@ #define BITCOIN_POLICY_PACKAGES_H #include <consensus/validation.h> +#include <policy/policy.h> #include <primitives/transaction.h> #include <vector> @@ -14,6 +15,7 @@ static constexpr uint32_t MAX_PACKAGE_COUNT{25}; /** Default maximum total virtual size of transactions in a package in KvB. */ static constexpr uint32_t MAX_PACKAGE_SIZE{101}; +static_assert(MAX_PACKAGE_SIZE * WITNESS_SCALE_FACTOR * 1000 >= MAX_STANDARD_TX_WEIGHT); /** A "reason" why a package was invalid. It may be that one or more of the included * transactions is invalid or the package itself violates our rules. @@ -31,4 +33,12 @@ using Package = std::vector<CTransactionRef>; class PackageValidationState : public ValidationState<PackageValidationResult> {}; +/** Context-free package policy checks: + * 1. The number of transactions cannot exceed MAX_PACKAGE_COUNT. + * 2. The total virtual size cannot exceed MAX_PACKAGE_SIZE. + * 3. If any dependencies exist between transactions, parents must appear before children. + * 4. Transactions cannot conflict, i.e., spend the same inputs. + */ +bool CheckPackage(const Package& txns, PackageValidationState& state); + #endif // BITCOIN_POLICY_PACKAGES_H |