Bitcoin Core  22.99.0
P2P Digital Currency
fees.cpp
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1 // Copyright (c) 2009-2010 Satoshi Nakamoto
2 // Copyright (c) 2009-2020 The Bitcoin Core developers
3 // Distributed under the MIT software license, see the accompanying
4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
5 
6 #include <wallet/fees.h>
7 
8 #include <wallet/coincontrol.h>
9 #include <wallet/wallet.h>
10 
11 
12 namespace wallet {
13 CAmount GetRequiredFee(const CWallet& wallet, unsigned int nTxBytes)
14 {
15  return GetRequiredFeeRate(wallet).GetFee(nTxBytes);
16 }
17 
18 
19 CAmount GetMinimumFee(const CWallet& wallet, unsigned int nTxBytes, const CCoinControl& coin_control, FeeCalculation* feeCalc)
20 {
21  return GetMinimumFeeRate(wallet, coin_control, feeCalc).GetFee(nTxBytes);
22 }
23 
25 {
26  return std::max(wallet.m_min_fee, wallet.chain().relayMinFee());
27 }
28 
29 CFeeRate GetMinimumFeeRate(const CWallet& wallet, const CCoinControl& coin_control, FeeCalculation* feeCalc)
30 {
31  /* User control of how to calculate fee uses the following parameter precedence:
32  1. coin_control.m_feerate
33  2. coin_control.m_confirm_target
34  3. m_pay_tx_fee (user-set member variable of wallet)
35  4. m_confirm_target (user-set member variable of wallet)
36  The first parameter that is set is used.
37  */
38  CFeeRate feerate_needed;
39  if (coin_control.m_feerate) { // 1.
40  feerate_needed = *(coin_control.m_feerate);
41  if (feeCalc) feeCalc->reason = FeeReason::PAYTXFEE;
42  // Allow to override automatic min/max check over coin control instance
43  if (coin_control.fOverrideFeeRate) return feerate_needed;
44  }
45  else if (!coin_control.m_confirm_target && wallet.m_pay_tx_fee != CFeeRate(0)) { // 3. TODO: remove magic value of 0 for wallet member m_pay_tx_fee
46  feerate_needed = wallet.m_pay_tx_fee;
47  if (feeCalc) feeCalc->reason = FeeReason::PAYTXFEE;
48  }
49  else { // 2. or 4.
50  // We will use smart fee estimation
51  unsigned int target = coin_control.m_confirm_target ? *coin_control.m_confirm_target : wallet.m_confirm_target;
52  // By default estimates are economical iff we are signaling opt-in-RBF
53  bool conservative_estimate = !coin_control.m_signal_bip125_rbf.value_or(wallet.m_signal_rbf);
54  // Allow to override the default fee estimate mode over the CoinControl instance
55  if (coin_control.m_fee_mode == FeeEstimateMode::CONSERVATIVE) conservative_estimate = true;
56  else if (coin_control.m_fee_mode == FeeEstimateMode::ECONOMICAL) conservative_estimate = false;
57 
58  feerate_needed = wallet.chain().estimateSmartFee(target, conservative_estimate, feeCalc);
59  if (feerate_needed == CFeeRate(0)) {
60  // if we don't have enough data for estimateSmartFee, then use fallback fee
61  feerate_needed = wallet.m_fallback_fee;
62  if (feeCalc) feeCalc->reason = FeeReason::FALLBACK;
63 
64  // directly return if fallback fee is disabled (feerate 0 == disabled)
65  if (wallet.m_fallback_fee == CFeeRate(0)) return feerate_needed;
66  }
67  // Obey mempool min fee when using smart fee estimation
68  CFeeRate min_mempool_feerate = wallet.chain().mempoolMinFee();
69  if (feerate_needed < min_mempool_feerate) {
70  feerate_needed = min_mempool_feerate;
71  if (feeCalc) feeCalc->reason = FeeReason::MEMPOOL_MIN;
72  }
73  }
74 
75  // prevent user from paying a fee below the required fee rate
76  CFeeRate required_feerate = GetRequiredFeeRate(wallet);
77  if (required_feerate > feerate_needed) {
78  feerate_needed = required_feerate;
79  if (feeCalc) feeCalc->reason = FeeReason::REQUIRED;
80  }
81  return feerate_needed;
82 }
83 
85 {
86  unsigned int highest_target = wallet.chain().estimateMaxBlocks();
87  CFeeRate discard_rate = wallet.chain().estimateSmartFee(highest_target, false /* conservative */);
88  // Don't let discard_rate be greater than longest possible fee estimate if we get a valid fee estimate
89  discard_rate = (discard_rate == CFeeRate(0)) ? wallet.m_discard_rate : std::min(discard_rate, wallet.m_discard_rate);
90  // Discard rate must be at least dustRelayFee
91  discard_rate = std::max(discard_rate, wallet.chain().relayDustFee());
92  return discard_rate;
93 }
94 } // namespace wallet
wallet.h
wallet::CCoinControl::m_confirm_target
std::optional< unsigned int > m_confirm_target
Override the default confirmation target if set.
Definition: coincontrol.h:49
wallet
Definition: node.h:38
wallet::GetMinimumFee
CAmount GetMinimumFee(const CWallet &wallet, unsigned int nTxBytes, const CCoinControl &coin_control, FeeCalculation *feeCalc)
Estimate the minimum fee considering user set parameters and the required fee.
Definition: fees.cpp:19
FeeReason::PAYTXFEE
@ PAYTXFEE
CFeeRate
Fee rate in satoshis per kilobyte: CAmount / kB.
Definition: feerate.h:29
FeeEstimateMode::ECONOMICAL
@ ECONOMICAL
Force estimateSmartFee to use non-conservative estimates.
FeeCalculation::reason
FeeReason reason
Definition: fees.h:78
fees.h
FeeCalculation
Definition: fees.h:75
FeeReason::FALLBACK
@ FALLBACK
wallet::CWallet
A CWallet maintains a set of transactions and balances, and provides the ability to create new transa...
Definition: wallet.h:232
FeeReason::MEMPOOL_MIN
@ MEMPOOL_MIN
wallet::CCoinControl::m_feerate
std::optional< CFeeRate > m_feerate
Override the wallet's m_pay_tx_fee if set.
Definition: coincontrol.h:47
CAmount
int64_t CAmount
Amount in satoshis (Can be negative)
Definition: amount.h:12
wallet::CCoinControl::m_signal_bip125_rbf
std::optional< bool > m_signal_bip125_rbf
Override the wallet's m_signal_rbf if set.
Definition: coincontrol.h:51
FeeReason::REQUIRED
@ REQUIRED
wallet::GetRequiredFeeRate
CFeeRate GetRequiredFeeRate(const CWallet &wallet)
Return the minimum required feerate taking into account the minimum relay feerate and user set minimu...
Definition: fees.cpp:24
FeeEstimateMode::CONSERVATIVE
@ CONSERVATIVE
Force estimateSmartFee to use conservative estimates.
wallet::GetRequiredFee
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:13
wallet::CCoinControl::fOverrideFeeRate
bool fOverrideFeeRate
Override automatic min/max checks on fee, m_feerate must be set if true.
Definition: coincontrol.h:45
wallet::CCoinControl::m_fee_mode
FeeEstimateMode m_fee_mode
Fee estimation mode to control arguments to estimateSmartFee.
Definition: coincontrol.h:57
CFeeRate::GetFee
CAmount GetFee(uint32_t num_bytes) const
Return the fee in satoshis for the given size in bytes.
Definition: feerate.cpp:23
coincontrol.h
wallet::CCoinControl
Coin Control Features.
Definition: coincontrol.h:29
wallet::GetDiscardRate
CFeeRate GetDiscardRate(const CWallet &wallet)
Return the maximum feerate for discarding change.
Definition: fees.cpp:84
wallet::GetMinimumFeeRate
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:29