Line data Source code
1 : // Copyright (c) 2017-2020 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 <policy/fees.h>
7 : #include <policy/policy.h>
8 : #include <util/moneystr.h>
9 : #include <util/rbf.h>
10 : #include <util/system.h>
11 : #include <util/translation.h>
12 : #include <wallet/coincontrol.h>
13 : #include <wallet/feebumper.h>
14 : #include <wallet/fees.h>
15 : #include <wallet/wallet.h>
16 :
17 : //! Check whether transaction has descendant in wallet or mempool, or has been
18 : //! mined, or conflicts with a mined transaction. Return a feebumper::Result.
19 183 : static feebumper::Result PreconditionChecks(const CWallet& wallet, const CWalletTx& wtx, std::vector<bilingual_str>& errors) EXCLUSIVE_LOCKS_REQUIRED(wallet.cs_wallet)
20 : {
21 183 : if (wallet.HasWalletSpend(wtx.GetHash())) {
22 1 : errors.push_back(Untranslated("Transaction has descendants in the wallet"));
23 1 : return feebumper::Result::INVALID_PARAMETER;
24 : }
25 :
26 : {
27 182 : if (wallet.chain().hasDescendantsInMempool(wtx.GetHash())) {
28 0 : errors.push_back(Untranslated("Transaction has descendants in the mempool"));
29 0 : return feebumper::Result::INVALID_PARAMETER;
30 : }
31 : }
32 :
33 182 : if (wtx.GetDepthInMainChain() != 0) {
34 0 : errors.push_back(Untranslated("Transaction has been mined, or is conflicted with a mined transaction"));
35 0 : return feebumper::Result::WALLET_ERROR;
36 : }
37 :
38 182 : if (!SignalsOptInRBF(*wtx.tx)) {
39 2 : errors.push_back(Untranslated("Transaction is not BIP 125 replaceable"));
40 2 : return feebumper::Result::WALLET_ERROR;
41 : }
42 :
43 180 : if (wtx.mapValue.count("replaced_by_txid")) {
44 1 : errors.push_back(strprintf(Untranslated("Cannot bump transaction %s which was already bumped by transaction %s"), wtx.GetHash().ToString(), wtx.mapValue.at("replaced_by_txid")));
45 1 : return feebumper::Result::WALLET_ERROR;
46 : }
47 :
48 : // check that original tx consists entirely of our inputs
49 : // 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)
50 179 : isminefilter filter = wallet.GetLegacyScriptPubKeyMan() && wallet.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS) ? ISMINE_WATCH_ONLY : ISMINE_SPENDABLE;
51 179 : if (!wallet.IsAllFromMe(*wtx.tx, filter)) {
52 1 : errors.push_back(Untranslated("Transaction contains inputs that don't belong to this wallet"));
53 1 : return feebumper::Result::WALLET_ERROR;
54 : }
55 :
56 :
57 178 : return feebumper::Result::OK;
58 183 : }
59 :
60 : //! Check if the user provided a valid feeRate
61 10 : static feebumper::Result CheckFeeRate(const CWallet& wallet, const CWalletTx& wtx, const CFeeRate& newFeerate, const int64_t maxTxSize, std::vector<bilingual_str>& errors)
62 : {
63 : // check that fee rate is higher than mempool's minimum fee
64 : // (no point in bumping fee if we know that the new tx won't be accepted to the mempool)
65 : // This may occur if the user set fee_rate or paytxfee too low, if fallbackfee is too low, or, perhaps,
66 : // in a rare situation where the mempool minimum fee increased significantly since the fee estimation just a
67 : // moment earlier. In this case, we report an error to the user, who may adjust the fee.
68 10 : CFeeRate minMempoolFeeRate = wallet.chain().mempoolMinFee();
69 :
70 10 : if (newFeerate.GetFeePerK() < minMempoolFeeRate.GetFeePerK()) {
71 0 : errors.push_back(strprintf(
72 0 : Untranslated("New fee rate (%s) is lower than the minimum fee rate (%s) to get into the mempool -- "),
73 0 : FormatMoney(newFeerate.GetFeePerK()),
74 0 : FormatMoney(minMempoolFeeRate.GetFeePerK())));
75 0 : return feebumper::Result::WALLET_ERROR;
76 : }
77 :
78 10 : CAmount new_total_fee = newFeerate.GetFee(maxTxSize);
79 :
80 10 : CFeeRate incrementalRelayFee = std::max(wallet.chain().relayIncrementalFee(), CFeeRate(WALLET_INCREMENTAL_RELAY_FEE));
81 :
82 : // Given old total fee and transaction size, calculate the old feeRate
83 10 : isminefilter filter = wallet.GetLegacyScriptPubKeyMan() && wallet.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS) ? ISMINE_WATCH_ONLY : ISMINE_SPENDABLE;
84 10 : CAmount old_fee = wtx.GetDebit(filter) - wtx.tx->GetValueOut();
85 10 : const int64_t txSize = GetVirtualTransactionSize(*(wtx.tx));
86 10 : CFeeRate nOldFeeRate(old_fee, txSize);
87 : // Min total fee is old fee + relay fee
88 10 : CAmount minTotalFee = nOldFeeRate.GetFee(maxTxSize) + incrementalRelayFee.GetFee(maxTxSize);
89 :
90 10 : if (new_total_fee < minTotalFee) {
91 2 : errors.push_back(strprintf(Untranslated("Insufficient total fee %s, must be at least %s (oldFee %s + incrementalFee %s)"),
92 1 : FormatMoney(new_total_fee), FormatMoney(minTotalFee), FormatMoney(nOldFeeRate.GetFee(maxTxSize)), FormatMoney(incrementalRelayFee.GetFee(maxTxSize))));
93 1 : return feebumper::Result::INVALID_PARAMETER;
94 : }
95 :
96 9 : CAmount requiredFee = GetRequiredFee(wallet, maxTxSize);
97 9 : if (new_total_fee < requiredFee) {
98 0 : errors.push_back(strprintf(Untranslated("Insufficient total fee (cannot be less than required fee %s)"),
99 0 : FormatMoney(requiredFee)));
100 0 : return feebumper::Result::INVALID_PARAMETER;
101 : }
102 :
103 : // Check that in all cases the new fee doesn't violate maxTxFee
104 9 : const CAmount max_tx_fee = wallet.m_default_max_tx_fee;
105 9 : if (new_total_fee > max_tx_fee) {
106 2 : errors.push_back(strprintf(Untranslated("Specified or calculated fee %s is too high (cannot be higher than -maxtxfee %s)"),
107 1 : FormatMoney(new_total_fee), FormatMoney(max_tx_fee)));
108 1 : return feebumper::Result::WALLET_ERROR;
109 : }
110 :
111 8 : return feebumper::Result::OK;
112 10 : }
113 :
114 83 : static CFeeRate EstimateFeeRate(const CWallet& wallet, const CWalletTx& wtx, const CAmount old_fee, CCoinControl& coin_control)
115 : {
116 : // Get the fee rate of the original transaction. This is calculated from
117 : // the tx fee/vsize, so it may have been rounded down. Add 1 satoshi to the
118 : // result.
119 83 : int64_t txSize = GetVirtualTransactionSize(*(wtx.tx));
120 83 : CFeeRate feerate(old_fee, txSize);
121 83 : feerate += CFeeRate(1);
122 :
123 : // The node has a configurable incremental relay fee. Increment the fee by
124 : // the minimum of that and the wallet's conservative
125 : // WALLET_INCREMENTAL_RELAY_FEE value to future proof against changes to
126 : // network wide policy for incremental relay fee that our node may not be
127 : // aware of. This ensures we're over the required relay fee rate
128 : // (BIP 125 rule 4). The replacement tx will be at least as large as the
129 : // original tx, so the total fee will be greater (BIP 125 rule 3)
130 83 : CFeeRate node_incremental_relay_fee = wallet.chain().relayIncrementalFee();
131 83 : CFeeRate wallet_incremental_relay_fee = CFeeRate(WALLET_INCREMENTAL_RELAY_FEE);
132 83 : feerate += std::max(node_incremental_relay_fee, wallet_incremental_relay_fee);
133 :
134 : // Fee rate must also be at least the wallet's GetMinimumFeeRate
135 83 : CFeeRate min_feerate(GetMinimumFeeRate(wallet, coin_control, /* feeCalc */ nullptr));
136 :
137 : // Set the required fee rate for the replacement transaction in coin control.
138 83 : return std::max(feerate, min_feerate);
139 83 : }
140 :
141 : namespace feebumper {
142 :
143 0 : bool TransactionCanBeBumped(const CWallet& wallet, const uint256& txid)
144 : {
145 0 : LOCK(wallet.cs_wallet);
146 0 : const CWalletTx* wtx = wallet.GetWalletTx(txid);
147 0 : if (wtx == nullptr) return false;
148 :
149 0 : std::vector<bilingual_str> errors_dummy;
150 0 : feebumper::Result res = PreconditionChecks(wallet, *wtx, errors_dummy);
151 0 : return res == feebumper::Result::OK;
152 0 : }
153 :
154 98 : Result CreateRateBumpTransaction(CWallet& wallet, const uint256& txid, const CCoinControl& coin_control, std::vector<bilingual_str>& errors,
155 : CAmount& old_fee, CAmount& new_fee, CMutableTransaction& mtx)
156 : {
157 : // We are going to modify coin control later, copy to re-use
158 98 : CCoinControl new_coin_control(coin_control);
159 :
160 98 : LOCK(wallet.cs_wallet);
161 98 : errors.clear();
162 98 : auto it = wallet.mapWallet.find(txid);
163 98 : if (it == wallet.mapWallet.end()) {
164 0 : errors.push_back(Untranslated("Invalid or non-wallet transaction id"));
165 0 : return Result::INVALID_ADDRESS_OR_KEY;
166 : }
167 98 : const CWalletTx& wtx = it->second;
168 :
169 98 : Result result = PreconditionChecks(wallet, wtx, errors);
170 98 : if (result != Result::OK) {
171 5 : return result;
172 : }
173 :
174 : // Fill in recipients(and preserve a single change key if there is one)
175 93 : std::vector<CRecipient> recipients;
176 277 : for (const auto& output : wtx.tx->vout) {
177 184 : if (!wallet.IsChange(output)) {
178 93 : CRecipient recipient = {output.scriptPubKey, output.nValue, false};
179 93 : recipients.push_back(recipient);
180 93 : } else {
181 91 : CTxDestination change_dest;
182 91 : ExtractDestination(output.scriptPubKey, change_dest);
183 91 : new_coin_control.destChange = change_dest;
184 91 : }
185 : }
186 :
187 93 : isminefilter filter = wallet.GetLegacyScriptPubKeyMan() && wallet.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS) ? ISMINE_WATCH_ONLY : ISMINE_SPENDABLE;
188 93 : old_fee = wtx.GetDebit(filter) - wtx.tx->GetValueOut();
189 :
190 93 : 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 10 : const int64_t maxTxSize = CalculateMaximumSignedTxSize(*wtx.tx, &wallet);
194 10 : Result res = CheckFeeRate(wallet, wtx, *new_coin_control.m_feerate, maxTxSize, errors);
195 10 : if (res != Result::OK) {
196 2 : return res;
197 : }
198 8 : } else {
199 : // The user did not provide a feeRate argument
200 83 : 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.
210 317 : for (const auto& inputs : wtx.tx->vin) {
211 226 : new_coin_control.Select(COutPoint(inputs.prevout));
212 : }
213 91 : new_coin_control.fAllowOtherInputs = true;
214 :
215 : // We cannot source new unconfirmed inputs(bip125 rule 2)
216 91 : new_coin_control.m_min_depth = 1;
217 :
218 91 : CTransactionRef tx_new = MakeTransactionRef();
219 91 : CAmount fee_ret;
220 91 : int change_pos_in_out = -1; // No requested location for change
221 91 : bilingual_str fail_reason;
222 91 : if (!wallet.CreateTransaction(recipients, tx_new, fee_ret, change_pos_in_out, fail_reason, new_coin_control, false)) {
223 2 : errors.push_back(Untranslated("Unable to create transaction.") + Untranslated(" ") + fail_reason);
224 2 : return Result::WALLET_ERROR;
225 : }
226 :
227 : // Write back new fee if successful
228 89 : new_fee = fee_ret;
229 :
230 : // Write back transaction
231 89 : mtx = CMutableTransaction(*tx_new);
232 : // Mark new tx not replaceable, if requested.
233 89 : if (!coin_control.m_signal_bip125_rbf.get_value_or(wallet.m_signal_rbf)) {
234 2 : for (auto& input : mtx.vin) {
235 1 : if (input.nSequence < 0xfffffffe) input.nSequence = 0xfffffffe;
236 : }
237 1 : }
238 :
239 89 : return Result::OK;
240 191 : }
241 :
242 85 : bool SignTransaction(CWallet& wallet, CMutableTransaction& mtx) {
243 85 : LOCK(wallet.cs_wallet);
244 85 : return wallet.SignTransaction(mtx);
245 85 : }
246 :
247 85 : Result CommitTransaction(CWallet& wallet, const uint256& txid, CMutableTransaction&& mtx, std::vector<bilingual_str>& errors, uint256& bumped_txid)
248 : {
249 85 : LOCK(wallet.cs_wallet);
250 85 : if (!errors.empty()) {
251 0 : return Result::MISC_ERROR;
252 : }
253 85 : auto it = txid.IsNull() ? wallet.mapWallet.end() : wallet.mapWallet.find(txid);
254 85 : if (it == wallet.mapWallet.end()) {
255 0 : errors.push_back(Untranslated("Invalid or non-wallet transaction id"));
256 0 : return Result::MISC_ERROR;
257 : }
258 85 : CWalletTx& oldWtx = it->second;
259 :
260 : // make sure the transaction still has no descendants and hasn't been mined in the meantime
261 85 : Result result = PreconditionChecks(wallet, oldWtx, errors);
262 85 : if (result != Result::OK) {
263 0 : return result;
264 : }
265 :
266 : // commit/broadcast the tx
267 85 : CTransactionRef tx = MakeTransactionRef(std::move(mtx));
268 85 : mapValue_t mapValue = oldWtx.mapValue;
269 85 : mapValue["replaces_txid"] = oldWtx.GetHash().ToString();
270 :
271 85 : wallet.CommitTransaction(tx, std::move(mapValue), oldWtx.vOrderForm);
272 :
273 : // mark the original tx as bumped
274 85 : bumped_txid = tx->GetHash();
275 85 : if (!wallet.MarkReplaced(oldWtx.GetHash(), bumped_txid)) {
276 : // TODO: see if JSON-RPC has a standard way of returning a response
277 : // along with an exception. It would be good to return information about
278 : // wtxBumped to the caller even if marking the original transaction
279 : // replaced does not succeed for some reason.
280 0 : errors.push_back(Untranslated("Created new bumpfee transaction but could not mark the original transaction as replaced"));
281 0 : }
282 : return Result::OK;
283 170 : }
284 :
285 : } // namespace feebumper
|
