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CheckEphemeralSpends: return boolean, and set child state and txid ou…
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…tparams
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@instagibbs
instagibbs committed Nov 20, 2024
1 parent cf0cee1 commit ba35a57
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Showing 5 changed files with 101 additions and 41 deletions.
5 changes: 4 additions & 1 deletion src/bench/mempool_ephemeral_spends.cpp
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Expand Up @@ -73,9 +73,12 @@ static void MempoolCheckEphemeralSpends(benchmark::Bench& bench)

uint32_t iteration{0};

TxValidationState dummy_state;
Txid dummy_txid;

bench.run([&]() NO_THREAD_SAFETY_ANALYSIS {

CheckEphemeralSpends({tx2_r}, /*dust_relay_rate=*/CFeeRate(iteration * COIN / 10), pool);
CheckEphemeralSpends({tx2_r}, /*dust_relay_rate=*/CFeeRate(iteration * COIN / 10), pool, dummy_state, dummy_txid);
iteration++;
});
}
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11 changes: 7 additions & 4 deletions src/policy/ephemeral_policy.cpp
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Expand Up @@ -30,11 +30,11 @@ bool PreCheckEphemeralTx(const CTransaction& tx, CFeeRate dust_relay_rate, CAmou
return true;
}

std::optional<Txid> CheckEphemeralSpends(const Package& package, CFeeRate dust_relay_rate, const CTxMemPool& tx_pool)
bool CheckEphemeralSpends(const Package& package, CFeeRate dust_relay_rate, const CTxMemPool& tx_pool, TxValidationState& out_child_state, Txid& out_child_txid)
{
if (!Assume(std::ranges::all_of(package, [](const auto& tx){return tx != nullptr;}))) {
// Bail out of spend checks if caller gave us an invalid package
return std::nullopt;
return true;
}

std::map<Txid, CTransactionRef> map_txid_ref;
Expand Down Expand Up @@ -83,9 +83,12 @@ std::optional<Txid> CheckEphemeralSpends(const Package& package, CFeeRate dust_r
}

if (!unspent_parent_dust.empty()) {
return tx->GetHash();
out_child_txid = tx->GetHash();
out_child_state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "missing-ephemeral-spends",
strprintf("tx %s did not spend parent's ephemeral dust", out_child_txid.ToString()));
return false;
}
}

return std::nullopt;
return true;
}
5 changes: 3 additions & 2 deletions src/policy/ephemeral_policy.h
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Expand Up @@ -50,8 +50,9 @@ bool PreCheckEphemeralTx(const CTransaction& tx, CFeeRate dust_relay_rate, CAmou
/** Must be called for each transaction(package) if any dust is in the package.
* Checks that each transaction's parents have their dust spent by the child,
* where parents are either in the mempool or in the package itself.
* @returns std::nullopt if all dust is properly spent, or the txid of the violating child spend.
* Sets out_child_state and out_child_txid on failure.
* @returns true if all dust is properly spent.
*/
std::optional<Txid> CheckEphemeralSpends(const Package& package, CFeeRate dust_relay_rate, const CTxMemPool& tx_pool);
bool CheckEphemeralSpends(const Package& package, CFeeRate dust_relay_rate, const CTxMemPool& tx_pool, TxValidationState& out_child_state, Txid& out_child_txid);

#endif // BITCOIN_POLICY_EPHEMERAL_POLICY_H
106 changes: 82 additions & 24 deletions src/test/txvalidation_tests.cpp
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Expand Up @@ -117,6 +117,9 @@ BOOST_FIXTURE_TEST_CASE(ephemeral_tests, RegTestingSetup)
TestMemPoolEntryHelper entry;
CTxMemPool::setEntries empty_ancestors;

TxValidationState child_state;
Txid child_txid;

// Arbitrary non-0 feerate for these tests
CFeeRate dustrelay(DUST_RELAY_TX_FEE);

Expand All @@ -130,88 +133,143 @@ BOOST_FIXTURE_TEST_CASE(ephemeral_tests, RegTestingSetup)
// We first start with nothing "in the mempool", using package checks

// Trivial single transaction with no dust
BOOST_CHECK(!CheckEphemeralSpends({dust_spend}, dustrelay, pool));
BOOST_CHECK(CheckEphemeralSpends({dust_spend}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, Txid());

// Now with dust, ok because the tx has no dusty parents
BOOST_CHECK(!CheckEphemeralSpends({grandparent_tx_1}, dustrelay, pool));
BOOST_CHECK(CheckEphemeralSpends({grandparent_tx_1}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, Txid());

// Dust checks pass
BOOST_CHECK(!CheckEphemeralSpends({grandparent_tx_1, dust_spend}, CFeeRate(0), pool));
BOOST_CHECK(!CheckEphemeralSpends({grandparent_tx_1, dust_spend}, dustrelay, pool));
BOOST_CHECK(CheckEphemeralSpends({grandparent_tx_1, dust_spend}, CFeeRate(0), pool, child_state, child_txid));
BOOST_CHECK(child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, Txid());
BOOST_CHECK(CheckEphemeralSpends({grandparent_tx_1, dust_spend}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, Txid());

auto dust_non_spend = make_tx({COutPoint{dust_txid, EPHEMERAL_DUST_INDEX - 1}}, /*version=*/2);

// Child spending non-dust only from parent should be disallowed even if dust otherwise spent
const auto dust_non_spend_txid{dust_non_spend->GetHash()};
const Txid null_txid;
assert(dust_non_spend_txid != null_txid);
BOOST_CHECK_EQUAL(CheckEphemeralSpends({grandparent_tx_1, dust_non_spend, dust_spend}, dustrelay, pool).value_or(null_txid), dust_non_spend_txid);
BOOST_CHECK_EQUAL(CheckEphemeralSpends({grandparent_tx_1, dust_spend, dust_non_spend}, dustrelay, pool).value_or(null_txid), dust_non_spend_txid);
BOOST_CHECK_EQUAL(CheckEphemeralSpends({grandparent_tx_1, dust_non_spend}, dustrelay, pool).value_or(null_txid), dust_non_spend_txid);
BOOST_CHECK(!CheckEphemeralSpends({grandparent_tx_1, dust_non_spend, dust_spend}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(!child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, dust_non_spend_txid);
child_state = TxValidationState();
child_txid = Txid();

BOOST_CHECK(!CheckEphemeralSpends({grandparent_tx_1, dust_spend, dust_non_spend}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(!child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, dust_non_spend_txid);
child_state = TxValidationState();
child_txid = Txid();

BOOST_CHECK(!CheckEphemeralSpends({grandparent_tx_1, dust_non_spend}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(!child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, dust_non_spend_txid);
child_state = TxValidationState();
child_txid = Txid();

auto grandparent_tx_2 = make_ephemeral_tx(random_outpoints(1), /*version=*/2);
const auto dust_txid_2 = grandparent_tx_2->GetHash();

// Spend dust from one but not another is ok, as long as second grandparent has no child
BOOST_CHECK(!CheckEphemeralSpends({grandparent_tx_1, grandparent_tx_2, dust_spend}, dustrelay, pool));
BOOST_CHECK(CheckEphemeralSpends({grandparent_tx_1, grandparent_tx_2, dust_spend}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, Txid());

auto dust_non_spend_both_parents = make_tx({COutPoint{dust_txid, EPHEMERAL_DUST_INDEX}, COutPoint{dust_txid_2, EPHEMERAL_DUST_INDEX - 1}}, /*version=*/2);
// But if we spend from the parent, it must spend dust
BOOST_CHECK_EQUAL(CheckEphemeralSpends({grandparent_tx_1, grandparent_tx_2, dust_non_spend_both_parents}, dustrelay, pool).value_or(null_txid), dust_non_spend_both_parents->GetHash());
BOOST_CHECK(!CheckEphemeralSpends({grandparent_tx_1, grandparent_tx_2, dust_non_spend_both_parents}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(!child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, dust_non_spend_both_parents->GetHash());
child_state = TxValidationState();
child_txid = Txid();

auto dust_spend_both_parents = make_tx({COutPoint{dust_txid, EPHEMERAL_DUST_INDEX}, COutPoint{dust_txid_2, EPHEMERAL_DUST_INDEX}}, /*version=*/2);
BOOST_CHECK(!CheckEphemeralSpends({grandparent_tx_1, grandparent_tx_2, dust_spend_both_parents}, dustrelay, pool));
BOOST_CHECK(CheckEphemeralSpends({grandparent_tx_1, grandparent_tx_2, dust_spend_both_parents}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, Txid());

// Spending other outputs is also correct, as long as the dusty one is spent
const std::vector<COutPoint> all_outpoints{COutPoint(dust_txid, 0), COutPoint(dust_txid, 1), COutPoint(dust_txid, 2),
COutPoint(dust_txid_2, 0), COutPoint(dust_txid_2, 1), COutPoint(dust_txid_2, 2)};
auto dust_spend_all_outpoints = make_tx(all_outpoints, /*version=*/2);
BOOST_CHECK(!CheckEphemeralSpends({grandparent_tx_1, grandparent_tx_2, dust_spend_all_outpoints}, dustrelay, pool));
BOOST_CHECK(CheckEphemeralSpends({grandparent_tx_1, grandparent_tx_2, dust_spend_all_outpoints}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, Txid());

// 2 grandparents with dust <- 1 dust-spending parent with dust <- child with no dust
auto parent_with_dust = make_ephemeral_tx({COutPoint{dust_txid, EPHEMERAL_DUST_INDEX}, COutPoint{dust_txid_2, EPHEMERAL_DUST_INDEX}}, /*version=*/2);
// Ok for parent to have dust
BOOST_CHECK(!CheckEphemeralSpends({grandparent_tx_1, grandparent_tx_2, parent_with_dust}, dustrelay, pool));
BOOST_CHECK(CheckEphemeralSpends({grandparent_tx_1, grandparent_tx_2, parent_with_dust}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, Txid());
auto child_no_dust = make_tx({COutPoint{parent_with_dust->GetHash(), EPHEMERAL_DUST_INDEX}}, /*version=*/2);
BOOST_CHECK(!CheckEphemeralSpends({grandparent_tx_1, grandparent_tx_2, parent_with_dust, child_no_dust}, dustrelay, pool));
BOOST_CHECK(CheckEphemeralSpends({grandparent_tx_1, grandparent_tx_2, parent_with_dust, child_no_dust}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, Txid());

// 2 grandparents with dust <- 1 dust-spending parent with dust <- child with dust
auto child_with_dust = make_ephemeral_tx({COutPoint{parent_with_dust->GetHash(), EPHEMERAL_DUST_INDEX}}, /*version=*/2);
BOOST_CHECK(!CheckEphemeralSpends({grandparent_tx_1, grandparent_tx_2, parent_with_dust, child_with_dust}, dustrelay, pool));
BOOST_CHECK(CheckEphemeralSpends({grandparent_tx_1, grandparent_tx_2, parent_with_dust, child_with_dust}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, Txid());

// Tests with parents in mempool

// Nothing in mempool, this should pass for any transaction
BOOST_CHECK(!CheckEphemeralSpends({grandparent_tx_1}, dustrelay, pool));
BOOST_CHECK(CheckEphemeralSpends({grandparent_tx_1}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, Txid());

// Add first grandparent to mempool and fetch entry
pool.addUnchecked(entry.FromTx(grandparent_tx_1));

// Ignores ancestors that aren't direct parents
BOOST_CHECK(!CheckEphemeralSpends({child_no_dust}, dustrelay, pool));
BOOST_CHECK(CheckEphemeralSpends({child_no_dust}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, Txid());

// Valid spend of dust with grandparent in mempool
BOOST_CHECK(!CheckEphemeralSpends({parent_with_dust}, dustrelay, pool));
BOOST_CHECK(CheckEphemeralSpends({parent_with_dust}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, Txid());

// Second grandparent in same package
BOOST_CHECK(!CheckEphemeralSpends({parent_with_dust, grandparent_tx_2}, dustrelay, pool));
BOOST_CHECK(CheckEphemeralSpends({parent_with_dust, grandparent_tx_2}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, Txid());

// Order in package doesn't matter
BOOST_CHECK(!CheckEphemeralSpends({grandparent_tx_2, parent_with_dust}, dustrelay, pool));
BOOST_CHECK(CheckEphemeralSpends({grandparent_tx_2, parent_with_dust}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, Txid());

// Add second grandparent to mempool
pool.addUnchecked(entry.FromTx(grandparent_tx_2));

// Only spends single dust out of two direct parents
BOOST_CHECK_EQUAL(CheckEphemeralSpends({dust_non_spend_both_parents}, dustrelay, pool).value_or(null_txid), dust_non_spend_both_parents->GetHash());
BOOST_CHECK(!CheckEphemeralSpends({dust_non_spend_both_parents}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(!child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, dust_non_spend_both_parents->GetHash());
child_state = TxValidationState();
child_txid = Txid();

// Spends both parents' dust
BOOST_CHECK(!CheckEphemeralSpends({parent_with_dust}, dustrelay, pool));
BOOST_CHECK(CheckEphemeralSpends({parent_with_dust}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, Txid());

// Now add dusty parent to mempool
pool.addUnchecked(entry.FromTx(parent_with_dust));

// Passes dust checks even with non-parent ancestors
BOOST_CHECK(!CheckEphemeralSpends({child_no_dust}, dustrelay, pool));
BOOST_CHECK(CheckEphemeralSpends({child_no_dust}, dustrelay, pool, child_state, child_txid));
BOOST_CHECK(child_state.IsValid());
BOOST_CHECK_EQUAL(child_txid, Txid());
}

BOOST_FIXTURE_TEST_CASE(version3_tests, RegTestingSetup)
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15 changes: 5 additions & 10 deletions src/validation.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1441,11 +1441,8 @@ MempoolAcceptResult MemPoolAccept::AcceptSingleTransaction(const CTransactionRef
}

if (m_pool.m_opts.require_standard) {
if (const auto ephemeral_violation{CheckEphemeralSpends(/*package=*/{ptx}, m_pool.m_opts.dust_relay_feerate, m_pool)}) {
const Txid& txid = ephemeral_violation.value();
Assume(txid == ptx->GetHash());
ws.m_state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "missing-ephemeral-spends",
strprintf("tx %s did not spend parent's ephemeral dust", txid.ToString()));
Txid dummy_txid;
if (!CheckEphemeralSpends(/*package=*/{ptx}, m_pool.m_opts.dust_relay_feerate, m_pool, ws.m_state, dummy_txid)) {
return MempoolAcceptResult::Failure(ws.m_state);
}
}
Expand Down Expand Up @@ -1590,11 +1587,9 @@ PackageMempoolAcceptResult MemPoolAccept::AcceptMultipleTransactions(const std::

// Now that we've bounded the resulting possible ancestry count, check package for dust spends
if (m_pool.m_opts.require_standard) {
if (const auto ephemeral_violation{CheckEphemeralSpends(txns, m_pool.m_opts.dust_relay_feerate, m_pool)}) {
const Txid& child_txid = ephemeral_violation.value();
TxValidationState child_state;
child_state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "missing-ephemeral-spends",
strprintf("tx %s did not spend parent's ephemeral dust", child_txid.ToString()));
TxValidationState child_state;
Txid child_txid;
if (!CheckEphemeralSpends(txns, m_pool.m_opts.dust_relay_feerate, m_pool, child_state, child_txid)) {
package_state.Invalid(PackageValidationResult::PCKG_TX, "unspent-dust");
results.emplace(child_txid, MempoolAcceptResult::Failure(child_state));
return PackageMempoolAcceptResult(package_state, std::move(results));
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