Bitcoin Core  0.19.99
P2P Digital Currency
feebumper.cpp
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1 // Copyright (c) 2017-2019 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 <interfaces/chain.h>
6 #include <wallet/coincontrol.h>
7 #include <wallet/feebumper.h>
8 #include <wallet/fees.h>
9 #include <wallet/wallet.h>
10 #include <policy/fees.h>
11 #include <policy/policy.h>
12 #include <util/moneystr.h>
13 #include <util/rbf.h>
14 #include <util/system.h>
15 
18 static feebumper::Result PreconditionChecks(const CWallet& wallet, const CWalletTx& wtx, std::vector<std::string>& errors) EXCLUSIVE_LOCKS_REQUIRED(wallet.cs_wallet)
19 {
20  if (wallet.HasWalletSpend(wtx.GetHash())) {
21  errors.push_back("Transaction has descendants in the wallet");
23  }
24 
25  {
26  if (wallet.chain().hasDescendantsInMempool(wtx.GetHash())) {
27  errors.push_back("Transaction has descendants in the mempool");
29  }
30  }
31 
32  if (wtx.GetDepthInMainChain() != 0) {
33  errors.push_back("Transaction has been mined, or is conflicted with a mined transaction");
35  }
36 
37  if (!SignalsOptInRBF(*wtx.tx)) {
38  errors.push_back("Transaction is not BIP 125 replaceable");
40  }
41 
42  if (wtx.mapValue.count("replaced_by_txid")) {
43  errors.push_back(strprintf("Cannot bump transaction %s which was already bumped by transaction %s", wtx.GetHash().ToString(), wtx.mapValue.at("replaced_by_txid")));
45  }
46 
47  // check that original tx consists entirely of our inputs
48  // if not, we can't bump the fee, because the wallet has no way of knowing the value of the other inputs (thus the fee)
49  isminefilter filter = wallet.GetLegacyScriptPubKeyMan() && wallet.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS) ? ISMINE_WATCH_ONLY : ISMINE_SPENDABLE;
50  if (!wallet.IsAllFromMe(*wtx.tx, filter)) {
51  errors.push_back("Transaction contains inputs that don't belong to this wallet");
53  }
54 
55 
56  return feebumper::Result::OK;
57 }
58 
60 static feebumper::Result CheckFeeRate(const CWallet& wallet, const CWalletTx& wtx, const CFeeRate& newFeerate, const int64_t maxTxSize, std::vector<std::string>& errors) {
61  // check that fee rate is higher than mempool's minimum fee
62  // (no point in bumping fee if we know that the new tx won't be accepted to the mempool)
63  // This may occur if the user set fee_rate or paytxfee too low, if fallbackfee is too low, or, perhaps,
64  // in a rare situation where the mempool minimum fee increased significantly since the fee estimation just a
65  // moment earlier. In this case, we report an error to the user, who may adjust the fee.
66  CFeeRate minMempoolFeeRate = wallet.chain().mempoolMinFee();
67 
68  if (newFeerate.GetFeePerK() < minMempoolFeeRate.GetFeePerK()) {
69  errors.push_back(strprintf(
70  "New fee rate (%s) is lower than the minimum fee rate (%s) to get into the mempool -- ",
71  FormatMoney(newFeerate.GetFeePerK()),
72  FormatMoney(minMempoolFeeRate.GetFeePerK())));
74  }
75 
76  CAmount new_total_fee = newFeerate.GetFee(maxTxSize);
77 
79 
80  // Given old total fee and transaction size, calculate the old feeRate
82  CAmount old_fee = wtx.GetDebit(filter) - wtx.tx->GetValueOut();
83  const int64_t txSize = GetVirtualTransactionSize(*(wtx.tx));
84  CFeeRate nOldFeeRate(old_fee, txSize);
85  // Min total fee is old fee + relay fee
86  CAmount minTotalFee = nOldFeeRate.GetFee(maxTxSize) + incrementalRelayFee.GetFee(maxTxSize);
87 
88  if (new_total_fee < minTotalFee) {
89  errors.push_back(strprintf("Insufficient total fee %s, must be at least %s (oldFee %s + incrementalFee %s)",
90  FormatMoney(new_total_fee), FormatMoney(minTotalFee), FormatMoney(nOldFeeRate.GetFee(maxTxSize)), FormatMoney(incrementalRelayFee.GetFee(maxTxSize))));
92  }
93 
94  CAmount requiredFee = GetRequiredFee(wallet, maxTxSize);
95  if (new_total_fee < requiredFee) {
96  errors.push_back(strprintf("Insufficient total fee (cannot be less than required fee %s)",
97  FormatMoney(requiredFee)));
99  }
100 
101  // Check that in all cases the new fee doesn't violate maxTxFee
102  const CAmount max_tx_fee = wallet.m_default_max_tx_fee;
103  if (new_total_fee > max_tx_fee) {
104  errors.push_back(strprintf("Specified or calculated fee %s is too high (cannot be higher than -maxtxfee %s)",
105  FormatMoney(new_total_fee), FormatMoney(max_tx_fee)));
107  }
108 
109  return feebumper::Result::OK;
110 }
111 
112 static CFeeRate EstimateFeeRate(const CWallet& wallet, const CWalletTx& wtx, const CAmount old_fee, CCoinControl& coin_control)
113 {
114  // Get the fee rate of the original transaction. This is calculated from
115  // the tx fee/vsize, so it may have been rounded down. Add 1 satoshi to the
116  // result.
117  int64_t txSize = GetVirtualTransactionSize(*(wtx.tx));
118  CFeeRate feerate(old_fee, txSize);
119  feerate += CFeeRate(1);
120 
121  // The node has a configurable incremental relay fee. Increment the fee by
122  // the minimum of that and the wallet's conservative
123  // WALLET_INCREMENTAL_RELAY_FEE value to future proof against changes to
124  // network wide policy for incremental relay fee that our node may not be
125  // aware of. This ensures we're over the required relay fee rate
126  // (BIP 125 rule 4). The replacement tx will be at least as large as the
127  // original tx, so the total fee will be greater (BIP 125 rule 3)
128  CFeeRate node_incremental_relay_fee = wallet.chain().relayIncrementalFee();
129  CFeeRate wallet_incremental_relay_fee = CFeeRate(WALLET_INCREMENTAL_RELAY_FEE);
130  feerate += std::max(node_incremental_relay_fee, wallet_incremental_relay_fee);
131 
132  // Fee rate must also be at least the wallet's GetMinimumFeeRate
133  CFeeRate min_feerate(GetMinimumFeeRate(wallet, coin_control, /* feeCalc */ nullptr));
134 
135  // Set the required fee rate for the replacement transaction in coin control.
136  return std::max(feerate, min_feerate);
137 }
138 
139 namespace feebumper {
140 
141 bool TransactionCanBeBumped(const CWallet& wallet, const uint256& txid)
142 {
143  auto locked_chain = wallet.chain().lock();
144  LOCK(wallet.cs_wallet);
145  const CWalletTx* wtx = wallet.GetWalletTx(txid);
146  if (wtx == nullptr) return false;
147 
148  std::vector<std::string> errors_dummy;
149  feebumper::Result res = PreconditionChecks(wallet, *wtx, errors_dummy);
150  return res == feebumper::Result::OK;
151 }
152 
153 Result CreateRateBumpTransaction(CWallet& wallet, const uint256& txid, const CCoinControl& coin_control, std::vector<std::string>& errors,
154  CAmount& old_fee, CAmount& new_fee, CMutableTransaction& mtx)
155 {
156  // We are going to modify coin control later, copy to re-use
157  CCoinControl new_coin_control(coin_control);
158 
159  auto locked_chain = wallet.chain().lock();
160  LOCK(wallet.cs_wallet);
161  errors.clear();
162  auto it = wallet.mapWallet.find(txid);
163  if (it == wallet.mapWallet.end()) {
164  errors.push_back("Invalid or non-wallet transaction id");
166  }
167  const CWalletTx& wtx = it->second;
168 
169  Result result = PreconditionChecks(wallet, wtx, errors);
170  if (result != Result::OK) {
171  return result;
172  }
173 
174  // Fill in recipients(and preserve a single change key if there is one)
175  std::vector<CRecipient> recipients;
176  for (const auto& output : wtx.tx->vout) {
177  if (!wallet.IsChange(output)) {
178  CRecipient recipient = {output.scriptPubKey, output.nValue, false};
179  recipients.push_back(recipient);
180  } else {
181  CTxDestination change_dest;
182  ExtractDestination(output.scriptPubKey, change_dest);
183  new_coin_control.destChange = change_dest;
184  }
185  }
186 
188  old_fee = wtx.GetDebit(filter) - wtx.tx->GetValueOut();
189 
190  if (coin_control.m_feerate) {
191  // The user provided a feeRate argument.
192  // We calculate this here to avoid compiler warning on the cs_wallet lock
193  const int64_t maxTxSize = CalculateMaximumSignedTxSize(*wtx.tx, &wallet);
194  Result res = CheckFeeRate(wallet, wtx, *new_coin_control.m_feerate, maxTxSize, errors);
195  if (res != Result::OK) {
196  return res;
197  }
198  } else {
199  // The user did not provide a feeRate argument
200  new_coin_control.m_feerate = EstimateFeeRate(wallet, wtx, old_fee, new_coin_control);
201  }
202 
203  // Fill in required inputs we are double-spending(all of them)
204  // N.B.: bip125 doesn't require all the inputs in the replaced transaction to be
205  // used in the replacement transaction, but it's very important for wallets to make
206  // sure that happens. If not, it would be possible to bump a transaction A twice to
207  // A2 and A3 where A2 and A3 don't conflict (or alternatively bump A to A2 and A2
208  // to A3 where A and A3 don't conflict). If both later get confirmed then the sender
209  // has accidentally double paid.
210  for (const auto& inputs : wtx.tx->vin) {
211  new_coin_control.Select(COutPoint(inputs.prevout));
212  }
213  new_coin_control.fAllowOtherInputs = true;
214 
215  // We cannot source new unconfirmed inputs(bip125 rule 2)
216  new_coin_control.m_min_depth = 1;
217 
219  CAmount fee_ret;
220  int change_pos_in_out = -1; // No requested location for change
221  std::string fail_reason;
222  if (!wallet.CreateTransaction(*locked_chain, recipients, tx_new, fee_ret, change_pos_in_out, fail_reason, new_coin_control, false)) {
223  errors.push_back("Unable to create transaction: " + fail_reason);
224  return Result::WALLET_ERROR;
225  }
226 
227  // Write back new fee if successful
228  new_fee = fee_ret;
229 
230  // Write back transaction
231  mtx = CMutableTransaction(*tx_new);
232  // Mark new tx not replaceable, if requested.
233  if (!coin_control.m_signal_bip125_rbf.get_value_or(wallet.m_signal_rbf)) {
234  for (auto& input : mtx.vin) {
235  if (input.nSequence < 0xfffffffe) input.nSequence = 0xfffffffe;
236  }
237  }
238 
239  return Result::OK;
240 }
241 
243  auto locked_chain = wallet.chain().lock();
244  LOCK(wallet.cs_wallet);
245  return wallet.SignTransaction(mtx);
246 }
247 
248 Result CommitTransaction(CWallet& wallet, const uint256& txid, CMutableTransaction&& mtx, std::vector<std::string>& errors, uint256& bumped_txid)
249 {
250  auto locked_chain = wallet.chain().lock();
251  LOCK(wallet.cs_wallet);
252  if (!errors.empty()) {
253  return Result::MISC_ERROR;
254  }
255  auto it = txid.IsNull() ? wallet.mapWallet.end() : wallet.mapWallet.find(txid);
256  if (it == wallet.mapWallet.end()) {
257  errors.push_back("Invalid or non-wallet transaction id");
258  return Result::MISC_ERROR;
259  }
260  CWalletTx& oldWtx = it->second;
261 
262  // make sure the transaction still has no descendants and hasn't been mined in the meantime
263  Result result = PreconditionChecks(wallet, oldWtx, errors);
264  if (result != Result::OK) {
265  return result;
266  }
267 
268  // commit/broadcast the tx
269  CTransactionRef tx = MakeTransactionRef(std::move(mtx));
270  mapValue_t mapValue = oldWtx.mapValue;
271  mapValue["replaces_txid"] = oldWtx.GetHash().ToString();
272 
273  wallet.CommitTransaction(tx, std::move(mapValue), oldWtx.vOrderForm);
274 
275  // mark the original tx as bumped
276  bumped_txid = tx->GetHash();
277  if (!wallet.MarkReplaced(oldWtx.GetHash(), bumped_txid)) {
278  // TODO: see if JSON-RPC has a standard way of returning a response
279  // along with an exception. It would be good to return information about
280  // wtxBumped to the caller even if marking the original transaction
281  // replaced does not succeed for some reason.
282  errors.push_back("Created new bumpfee transaction but could not mark the original transaction as replaced");
283  }
284  return Result::OK;
285 }
286 
287 } // namespace feebumper
std::shared_ptr< const CTransaction > CTransactionRef
Definition: transaction.h:408
bool IsWalletFlagSet(uint64_t flag) const override
check if a certain wallet flag is set
Definition: wallet.cpp:1377
bool SignTransaction(CWallet &wallet, CMutableTransaction &mtx)
Sign the new transaction,.
Definition: feebumper.cpp:242
const CWalletTx * GetWalletTx(const uint256 &hash) const
Definition: wallet.cpp:258
bool ExtractDestination(const CScript &scriptPubKey, CTxDestination &addressRet)
Parse a standard scriptPubKey for the destination address.
Definition: standard.cpp:156
std::map< std::string, std::string > mapValue_t
Definition: wallet.h:201
Result CommitTransaction(CWallet &wallet, const uint256 &txid, CMutableTransaction &&mtx, std::vector< std::string > &errors, uint256 &bumped_txid)
Commit the bumpfee transaction.
Definition: feebumper.cpp:248
virtual CFeeRate mempoolMinFee()=0
Mempool minimum fee.
#define strprintf
Format arguments and return the string or write to given std::ostream (see tinyformat::format doc for...
Definition: tinyformat.h:1164
std::vector< CTxIn > vin
Definition: transaction.h:368
CAmount GetDebit(const isminefilter &filter) const
filter decides which addresses will count towards the debit
Definition: wallet.cpp:1819
static CTransactionRef MakeTransactionRef()
Definition: transaction.h:409
bool CreateTransaction(interfaces::Chain::Lock &locked_chain, const std::vector< CRecipient > &vecSend, CTransactionRef &tx, CAmount &nFeeRet, int &nChangePosInOut, std::string &strFailReason, const CCoinControl &coin_control, bool sign=true)
Create a new transaction paying the recipients with a set of coins selected by SelectCoins(); Also cr...
Definition: wallet.cpp:2721
int m_min_depth
Minimum chain depth value for coin availability.
Definition: coincontrol.h:48
CAmount m_default_max_tx_fee
Absolute maximum transaction fee (in satoshis) used by default for the wallet.
Definition: wallet.h:992
int64_t GetVirtualTransactionSize(int64_t nWeight, int64_t nSigOpCost, unsigned int bytes_per_sigop)
Compute the virtual transaction size (weight reinterpreted as bytes).
Definition: policy.cpp:238
std::string FormatMoney(const CAmount &n)
Money parsing/formatting utilities.
Definition: moneystr.cpp:12
bool SignalsOptInRBF(const CTransaction &tx)
Definition: rbf.cpp:9
bool MarkReplaced(const uint256 &originalHash, const uint256 &newHash)
Mark a transaction as replaced by another transaction (e.g., BIP 125).
Definition: wallet.cpp:691
bool IsChange(const CTxOut &txout) const
Definition: wallet.cpp:1224
bool IsNull() const
Definition: uint256.h:30
Coin Control Features.
Definition: coincontrol.h:22
CFeeRate GetMinimumFeeRate(const CWallet &wallet, const CCoinControl &coin_control, FeeCalculation *feeCalc)
Estimate the minimum fee rate considering user set parameters and the required fee.
Definition: fees.cpp:28
mapValue_t mapValue
Key/value map with information about the transaction.
Definition: wallet.h:292
interfaces::Chain & chain() const
Interface for accessing chain state.
Definition: wallet.h:786
int64_t CAmount
Amount in satoshis (Can be negative)
Definition: amount.h:12
Optional< bool > m_signal_bip125_rbf
Override the wallet&#39;s m_signal_rbf if set.
Definition: coincontrol.h:40
void push_back(const T &value)
Definition: prevector.h:437
CScript scriptPubKey
Definition: wallet.h:196
void CommitTransaction(CTransactionRef tx, mapValue_t mapValue, std::vector< std::pair< std::string, std::string >> orderForm)
Submit the transaction to the node&#39;s mempool and then relay to peers.
Definition: wallet.cpp:3072
LegacyScriptPubKeyMan * GetLegacyScriptPubKeyMan() const
Get the LegacyScriptPubKeyMan which is used for all types, internal, and external.
Definition: wallet.cpp:4322
#define LOCK(cs)
Definition: sync.h:218
bool TransactionCanBeBumped(const CWallet &wallet, const uint256 &txid)
Return whether transaction can be bumped.
Definition: feebumper.cpp:141
static CFeeRate EstimateFeeRate(const CWallet &wallet, const CWalletTx &wtx, const CAmount old_fee, CCoinControl &coin_control)
Definition: feebumper.cpp:112
CTxDestination destChange
Custom change destination, if not set an address is generated.
Definition: coincontrol.h:26
void Select(const COutPoint &output)
Definition: coincontrol.h:69
bool fAllowOtherInputs
If false, allows unselected inputs, but requires all selected inputs be used.
Definition: coincontrol.h:30
uint8_t isminefilter
Definition: wallet.h:30
std::string ToString() const
Definition: uint256.cpp:60
const uint256 & GetHash() const
Definition: wallet.h:542
virtual std::unique_ptr< Lock > lock(bool try_lock=false)=0
Return Lock interface.
An outpoint - a combination of a transaction hash and an index n into its vout.
Definition: transaction.h:18
CFeeRate incrementalRelayFee
Definition: settings.cpp:12
A transaction with a bunch of additional info that only the owner cares about.
Definition: wallet.h:256
static feebumper::Result CheckFeeRate(const CWallet &wallet, const CWalletTx &wtx, const CFeeRate &newFeerate, const int64_t maxTxSize, std::vector< std::string > &errors)
Check if the user provided a valid feeRate.
Definition: feebumper.cpp:60
256-bit opaque blob.
Definition: uint256.h:120
#define EXCLUSIVE_LOCKS_REQUIRED(...)
Definition: threadsafety.h:51
Result CreateRateBumpTransaction(CWallet &wallet, const uint256 &txid, const CCoinControl &coin_control, std::vector< std::string > &errors, CAmount &old_fee, CAmount &new_fee, CMutableTransaction &mtx)
Create bumpfee transaction based on feerate estimates.
Definition: feebumper.cpp:153
A CWallet maintains a set of transactions and balances, and provides the ability to create new transa...
Definition: wallet.h:609
Fee rate in satoshis per kilobyte: CAmount / kB.
Definition: feerate.h:19
RecursiveMutex cs_wallet
Definition: wallet.h:720
A mutable version of CTransaction.
Definition: transaction.h:366
static const CAmount WALLET_INCREMENTAL_RELAY_FEE
minimum recommended increment for BIP 125 replacement txs
Definition: wallet.h:75
CAmount GetRequiredFee(const CWallet &wallet, unsigned int nTxBytes)
Return the minimum required absolute fee for this size based on the required fee rate.
Definition: fees.cpp:12
Optional< CFeeRate > m_feerate
Override the wallet&#39;s m_pay_tx_fee if set.
Definition: coincontrol.h:36
boost::variant< CNoDestination, PKHash, ScriptHash, WitnessV0ScriptHash, WitnessV0KeyHash, WitnessUnknown > CTxDestination
A txout script template with a specific destination.
Definition: standard.h:143
auto it
Definition: validation.cpp:361
bool m_signal_rbf
Definition: wallet.h:979
static feebumper::Result PreconditionChecks(const CWallet &wallet, const CWalletTx &wtx, std::vector< std::string > &errors) EXCLUSIVE_LOCKS_REQUIRED(wallet.cs_wallet)
Check whether transaction has descendant in wallet or mempool, or has been mined, or conflicts with a...
Definition: feebumper.cpp:18
bool SignTransaction(CMutableTransaction &tx) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet)
Definition: wallet.cpp:2414
virtual CFeeRate relayIncrementalFee()=0
Relay incremental fee setting (-incrementalrelayfee), reflecting cost of relay.
CAmount GetFeePerK() const
Return the fee in satoshis for a size of 1000 bytes.
Definition: feerate.h:41
CTransactionRef tx
Definition: wallet.h:352
int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet, bool use_max_sig)
Definition: wallet.cpp:1493
std::vector< std::pair< std::string, std::string > > vOrderForm
Definition: wallet.h:293
CAmount GetFee(size_t nBytes) const
Return the fee in satoshis for the given size in bytes.
Definition: feerate.cpp:23