diff --git a/src/init.cpp b/src/init.cpp index f3a3a1d27..20c204a5c 100644 --- a/src/init.cpp +++ b/src/init.cpp @@ -468,6 +468,7 @@ std::string HelpMessage(HelpMessageMode mode) if (showDebug) { strUsage += HelpMessageOpt("-acceptnonstdtxn", strprintf("Relay and mine \"non-standard\" transactions (%sdefault: %u)", "testnet/regtest only; ", !Params(CBaseChainParams::TESTNET).RequireStandard())); strUsage += HelpMessageOpt("-incrementalrelayfee=", strprintf("Fee rate (in %s/kB) used to define cost of relay, used for mempool limiting and BIP 125 replacement. (default: %s)", CURRENCY_UNIT, FormatMoney(DEFAULT_INCREMENTAL_RELAY_FEE))); + strUsage += HelpMessageOpt("-dustrelayfee=", strprintf("Fee rate (in %s/kB) used to defined dust, the value of an output such that it will cost about 1/3 of its value in fees at this fee rate to spend it. (default: %s)", CURRENCY_UNIT, FormatMoney(DUST_RELAY_TX_FEE))); } strUsage += HelpMessageOpt("-bytespersigop", strprintf(_("Equivalent bytes per sigop in transactions for relay and mining (default: %u)"), DEFAULT_BYTES_PER_SIGOP)); strUsage += HelpMessageOpt("-datacarrier", strprintf(_("Relay and mine data carrier transactions (default: %u)"), DEFAULT_ACCEPT_DATACARRIER)); @@ -995,6 +996,16 @@ bool AppInitParameterInteraction() return InitError(AmountErrMsg("blockmintxfee", GetArg("-blockmintxfee", ""))); } + // Feerate used to define dust. Shouldn't be changed lightly as old + // implementations may inadvertently create non-standard transactions + if (IsArgSet("-dustrelayfee")) + { + CAmount n = 0; + if (!ParseMoney(GetArg("-dustrelayfee", ""), n) || 0 == n) + return InitError(AmountErrMsg("dustrelayfee", GetArg("-dustrelayfee", ""))); + dustRelayFee = CFeeRate(n); + } + fRequireStandard = !GetBoolArg("-acceptnonstdtxn", !chainparams.RequireStandard()); if (chainparams.RequireStandard() && !fRequireStandard) return InitError(strprintf("acceptnonstdtxn is not currently supported for %s chain", chainparams.NetworkIDString())); diff --git a/src/policy/policy.cpp b/src/policy/policy.cpp index 4dacd6b54..ec398f662 100644 --- a/src/policy/policy.cpp +++ b/src/policy/policy.cpp @@ -105,7 +105,7 @@ bool IsStandardTx(const CTransaction& tx, std::string& reason, const bool witnes else if ((whichType == TX_MULTISIG) && (!fIsBareMultisigStd)) { reason = "bare-multisig"; return false; - } else if (txout.IsDust(::minRelayTxFee)) { + } else if (txout.IsDust(dustRelayFee)) { reason = "dust"; return false; } @@ -207,6 +207,7 @@ bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs) } CFeeRate incrementalRelayFee = CFeeRate(DEFAULT_INCREMENTAL_RELAY_FEE); +CFeeRate dustRelayFee = CFeeRate(DUST_RELAY_TX_FEE); unsigned int nBytesPerSigOp = DEFAULT_BYTES_PER_SIGOP; int64_t GetVirtualTransactionSize(int64_t nWeight, int64_t nSigOpCost) diff --git a/src/policy/policy.h b/src/policy/policy.h index 039122a59..9b1323ac2 100644 --- a/src/policy/policy.h +++ b/src/policy/policy.h @@ -40,6 +40,12 @@ static const unsigned int MAX_STANDARD_P2WSH_STACK_ITEMS = 100; static const unsigned int MAX_STANDARD_P2WSH_STACK_ITEM_SIZE = 80; /** The maximum size of a standard witnessScript */ static const unsigned int MAX_STANDARD_P2WSH_SCRIPT_SIZE = 3600; +/** Min feerate for defining dust. Historically this has been the same as the + * minRelayTxFee, however changing the dust limit changes which transactions are + * standard and should be done with care and ideally rarely. It makes sense to + * only increase the dust limit after prior releases were already not creating + * outputs below the new threshold */ +static const unsigned int DUST_RELAY_TX_FEE = 1000; /** * Standard script verification flags that standard transactions will comply * with. However scripts violating these flags may still be present in valid @@ -88,6 +94,7 @@ bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs) bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs); extern CFeeRate incrementalRelayFee; +extern CFeeRate dustRelayFee; extern unsigned int nBytesPerSigOp; /** Compute the virtual transaction size (weight reinterpreted as bytes). */ diff --git a/src/qt/coincontroldialog.cpp b/src/qt/coincontroldialog.cpp index a0c281347..f8aba70d9 100644 --- a/src/qt/coincontroldialog.cpp +++ b/src/qt/coincontroldialog.cpp @@ -15,7 +15,8 @@ #include "wallet/coincontrol.h" #include "init.h" -#include "validation.h" // For minRelayTxFee +#include "policy/policy.h" +#include "validation.h" // For mempool #include "wallet/wallet.h" #include // for 'map_list_of()' @@ -432,7 +433,7 @@ void CoinControlDialog::updateLabels(WalletModel *model, QDialog* dialog) { CTxOut txout(amount, (CScript)std::vector(24, 0)); txDummy.vout.push_back(txout); - if (txout.IsDust(::minRelayTxFee)) + if (txout.IsDust(dustRelayFee)) fDust = true; } } @@ -545,10 +546,10 @@ void CoinControlDialog::updateLabels(WalletModel *model, QDialog* dialog) if (nChange > 0 && nChange < MIN_CHANGE) { CTxOut txout(nChange, (CScript)std::vector(24, 0)); - if (txout.IsDust(::minRelayTxFee)) + if (txout.IsDust(dustRelayFee)) { if (CoinControlDialog::fSubtractFeeFromAmount) // dust-change will be raised until no dust - nChange = txout.GetDustThreshold(::minRelayTxFee); + nChange = txout.GetDustThreshold(dustRelayFee); else { nPayFee += nChange; diff --git a/src/qt/guiutil.cpp b/src/qt/guiutil.cpp index 4463cfdae..de6e09b8b 100644 --- a/src/qt/guiutil.cpp +++ b/src/qt/guiutil.cpp @@ -11,7 +11,7 @@ #include "primitives/transaction.h" #include "init.h" -#include "validation.h" // For minRelayTxFee +#include "policy/policy.h" #include "protocol.h" #include "script/script.h" #include "script/standard.h" @@ -257,7 +257,7 @@ bool isDust(const QString& address, const CAmount& amount) CTxDestination dest = CBitcoinAddress(address.toStdString()).Get(); CScript script = GetScriptForDestination(dest); CTxOut txOut(amount, script); - return txOut.IsDust(::minRelayTxFee); + return txOut.IsDust(dustRelayFee); } QString HtmlEscape(const QString& str, bool fMultiLine) diff --git a/src/qt/paymentserver.cpp b/src/qt/paymentserver.cpp index 6b2871424..688e8123a 100644 --- a/src/qt/paymentserver.cpp +++ b/src/qt/paymentserver.cpp @@ -10,7 +10,7 @@ #include "base58.h" #include "chainparams.h" -#include "validation.h" // For minRelayTxFee +#include "policy/policy.h" #include "ui_interface.h" #include "util.h" #include "wallet/wallet.h" @@ -582,7 +582,7 @@ bool PaymentServer::processPaymentRequest(const PaymentRequestPlus& request, Sen // Extract and check amounts CTxOut txOut(sendingTo.second, sendingTo.first); - if (txOut.IsDust(::minRelayTxFee)) { + if (txOut.IsDust(dustRelayFee)) { Q_EMIT message(tr("Payment request error"), tr("Requested payment amount of %1 is too small (considered dust).") .arg(BitcoinUnits::formatWithUnit(optionsModel->getDisplayUnit(), sendingTo.second)), CClientUIInterface::MSG_ERROR); diff --git a/src/test/transaction_tests.cpp b/src/test/transaction_tests.cpp index cd9294c7a..53a2de1ce 100644 --- a/src/test/transaction_tests.cpp +++ b/src/test/transaction_tests.cpp @@ -692,7 +692,7 @@ BOOST_AUTO_TEST_CASE(test_IsStandard) BOOST_CHECK(IsStandardTx(t, reason)); // Check dust with default relay fee: - CAmount nDustThreshold = 182 * minRelayTxFee.GetFeePerK()/1000 * 3; + CAmount nDustThreshold = 182 * dustRelayFee.GetFeePerK()/1000 * 3; BOOST_CHECK_EQUAL(nDustThreshold, 546); // dust: t.vout[0].nValue = nDustThreshold - 1; @@ -703,14 +703,14 @@ BOOST_AUTO_TEST_CASE(test_IsStandard) // Check dust with odd relay fee to verify rounding: // nDustThreshold = 182 * 1234 / 1000 * 3 - minRelayTxFee = CFeeRate(1234); + dustRelayFee = CFeeRate(1234); // dust: t.vout[0].nValue = 672 - 1; BOOST_CHECK(!IsStandardTx(t, reason)); // not dust: t.vout[0].nValue = 672; BOOST_CHECK(IsStandardTx(t, reason)); - minRelayTxFee = CFeeRate(DEFAULT_MIN_RELAY_TX_FEE); + dustRelayFee = CFeeRate(DUST_RELAY_TX_FEE); t.vout[0].scriptPubKey = CScript() << OP_1; BOOST_CHECK(!IsStandardTx(t, reason)); diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp index 967683256..5f442fd21 100644 --- a/src/wallet/wallet.cpp +++ b/src/wallet/wallet.cpp @@ -2335,7 +2335,7 @@ bool CWallet::CreateTransaction(const vector& vecSend, CWalletTx& wt } } - if (txout.IsDust(::minRelayTxFee)) + if (txout.IsDust(dustRelayFee)) { if (recipient.fSubtractFeeFromAmount && nFeeRet > 0) { @@ -2413,16 +2413,16 @@ bool CWallet::CreateTransaction(const vector& vecSend, CWalletTx& wt // We do not move dust-change to fees, because the sender would end up paying more than requested. // This would be against the purpose of the all-inclusive feature. // So instead we raise the change and deduct from the recipient. - if (nSubtractFeeFromAmount > 0 && newTxOut.IsDust(::minRelayTxFee)) + if (nSubtractFeeFromAmount > 0 && newTxOut.IsDust(dustRelayFee)) { - CAmount nDust = newTxOut.GetDustThreshold(::minRelayTxFee) - newTxOut.nValue; + CAmount nDust = newTxOut.GetDustThreshold(dustRelayFee) - newTxOut.nValue; newTxOut.nValue += nDust; // raise change until no more dust for (unsigned int i = 0; i < vecSend.size(); i++) // subtract from first recipient { if (vecSend[i].fSubtractFeeFromAmount) { txNew.vout[i].nValue -= nDust; - if (txNew.vout[i].IsDust(::minRelayTxFee)) + if (txNew.vout[i].IsDust(dustRelayFee)) { strFailReason = _("The transaction amount is too small to send after the fee has been deducted"); return false; @@ -2434,7 +2434,7 @@ bool CWallet::CreateTransaction(const vector& vecSend, CWalletTx& wt // Never create dust outputs; if we would, just // add the dust to the fee. - if (newTxOut.IsDust(::minRelayTxFee)) + if (newTxOut.IsDust(dustRelayFee)) { nChangePosInOut = -1; nFeeRet += nChange;