MOVEONLY: context-free package policies

Co-authored-by: ariard <antoine.riard@gmail.com>
This commit is contained in:
glozow 2021-06-02 16:19:29 +01:00
parent 5cac95cd15
commit ee862d6efb
4 changed files with 76 additions and 55 deletions

View file

@ -348,6 +348,7 @@ libbitcoin_server_a_SOURCES = \
node/ui_interface.cpp \
noui.cpp \
policy/fees.cpp \
policy/packages.cpp \
policy/rbf.cpp \
policy/settings.cpp \
pow.cpp \

62
src/policy/packages.cpp Normal file
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@ -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;
}

View file

@ -33,4 +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

View file

@ -1083,65 +1083,15 @@ PackageMempoolAcceptResult MemPoolAccept::AcceptMultipleTransactions(const std::
{
AssertLockHeld(cs_main);
// These context-free package limits can be done before taking the mempool lock.
PackageValidationState package_state;
const unsigned int package_count = txns.size();
if (!CheckPackage(txns, package_state)) return PackageMempoolAcceptResult(package_state, {});
// These context-free package limits can be checked before taking the mempool lock.
if (package_count > MAX_PACKAGE_COUNT) {
package_state.Invalid(PackageValidationResult::PCKG_POLICY, "package-too-many-transactions");
return PackageMempoolAcceptResult(package_state, {});
}
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) {
package_state.Invalid(PackageValidationResult::PCKG_POLICY, "package-too-large");
return PackageMempoolAcceptResult(package_state, {});
}
// Construct workspaces and check package policies.
std::vector<Workspace> workspaces{};
workspaces.reserve(package_count);
{
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(); });
// 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).
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.
package_state.Invalid(PackageValidationResult::PCKG_POLICY, "package-not-sorted");
return PackageMempoolAcceptResult(package_state, {});
}
}
later_txids.erase(tx->GetHash());
workspaces.emplace_back(Workspace(tx));
}
}
workspaces.reserve(txns.size());
std::transform(txns.cbegin(), txns.cend(), std::back_inserter(workspaces),
[](const auto& tx) { return Workspace(tx); });
std::map<const uint256, const MempoolAcceptResult> results;
{
// 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.
package_state.Invalid(PackageValidationResult::PCKG_POLICY, "conflict-in-package");
return PackageMempoolAcceptResult(package_state, {});
}
}
// 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; });
}
}
LOCK(m_pool.cs);