forked from bitcoin/bitcoin
-
Notifications
You must be signed in to change notification settings - Fork 1
/
Copy pathspend.cpp
1251 lines (1082 loc) · 60 KB
/
spend.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
// Copyright (c) 2021-2022 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <algorithm>
#include <common/args.h>
#include <common/system.h>
#include <consensus/amount.h>
#include <consensus/validation.h>
#include <interfaces/chain.h>
#include <numeric>
#include <policy/policy.h>
#include <primitives/transaction.h>
#include <script/signingprovider.h>
#include <util/check.h>
#include <util/fees.h>
#include <util/moneystr.h>
#include <util/rbf.h>
#include <util/trace.h>
#include <util/translation.h>
#include <wallet/coincontrol.h>
#include <wallet/fees.h>
#include <wallet/receive.h>
#include <wallet/spend.h>
#include <wallet/transaction.h>
#include <wallet/wallet.h>
#include <cmath>
using interfaces::FoundBlock;
namespace wallet {
static constexpr size_t OUTPUT_GROUP_MAX_ENTRIES{100};
int CalculateMaximumSignedInputSize(const CTxOut& txout, const COutPoint outpoint, const SigningProvider* provider, bool can_grind_r, const CCoinControl* coin_control)
{
CMutableTransaction txn;
txn.vin.push_back(CTxIn(outpoint));
if (!provider || !DummySignInput(*provider, txn.vin[0], txout, can_grind_r, coin_control)) {
return -1;
}
return GetVirtualTransactionInputSize(txn.vin[0]);
}
int CalculateMaximumSignedInputSize(const CTxOut& txout, const CWallet* wallet, const CCoinControl* coin_control)
{
const std::unique_ptr<SigningProvider> provider = wallet->GetSolvingProvider(txout.scriptPubKey);
return CalculateMaximumSignedInputSize(txout, COutPoint(), provider.get(), wallet->CanGrindR(), coin_control);
}
// txouts needs to be in the order of tx.vin
TxSize CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet, const std::vector<CTxOut>& txouts, const CCoinControl* coin_control)
{
CMutableTransaction txNew(tx);
if (!wallet->DummySignTx(txNew, txouts, coin_control)) return TxSize{-1, -1};
CTransaction ctx(txNew);
int64_t vsize = GetVirtualTransactionSize(ctx);
int64_t weight = GetTransactionWeight(ctx);
return TxSize{vsize, weight};
}
TxSize CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet, const CCoinControl* coin_control)
{
std::vector<CTxOut> txouts;
// Look up the inputs. The inputs are either in the wallet, or in coin_control.
for (const CTxIn& input : tx.vin) {
const auto mi = wallet->mapWallet.find(input.prevout.hash);
// Can not estimate size without knowing the input details
if (mi != wallet->mapWallet.end()) {
assert(input.prevout.n < mi->second.tx->vout.size());
txouts.emplace_back(mi->second.tx->vout.at(input.prevout.n));
} else if (coin_control) {
const auto& txout{coin_control->GetExternalOutput(input.prevout)};
if (!txout) return TxSize{-1, -1};
txouts.emplace_back(*txout);
} else {
return TxSize{-1, -1};
}
}
return CalculateMaximumSignedTxSize(tx, wallet, txouts, coin_control);
}
size_t CoinsResult::Size() const
{
size_t size{0};
for (const auto& it : coins) {
size += it.second.size();
}
return size;
}
std::vector<COutput> CoinsResult::All() const
{
std::vector<COutput> all;
all.reserve(coins.size());
for (const auto& it : coins) {
all.insert(all.end(), it.second.begin(), it.second.end());
}
return all;
}
void CoinsResult::Clear() {
coins.clear();
}
void CoinsResult::Erase(const std::unordered_set<COutPoint, SaltedOutpointHasher>& coins_to_remove)
{
for (auto& [type, vec] : coins) {
auto remove_it = std::remove_if(vec.begin(), vec.end(), [&](const COutput& coin) {
// remove it if it's on the set
if (coins_to_remove.count(coin.outpoint) == 0) return false;
// update cached amounts
total_amount -= coin.txout.nValue;
if (coin.HasEffectiveValue()) total_effective_amount = *total_effective_amount - coin.GetEffectiveValue();
return true;
});
vec.erase(remove_it, vec.end());
}
}
void CoinsResult::Shuffle(FastRandomContext& rng_fast)
{
for (auto& it : coins) {
::Shuffle(it.second.begin(), it.second.end(), rng_fast);
}
}
void CoinsResult::Add(OutputType type, const COutput& out)
{
coins[type].emplace_back(out);
total_amount += out.txout.nValue;
if (out.HasEffectiveValue()) {
total_effective_amount = total_effective_amount.has_value() ?
*total_effective_amount + out.GetEffectiveValue() : out.GetEffectiveValue();
}
}
static OutputType GetOutputType(TxoutType type, bool is_from_p2sh)
{
switch (type) {
case TxoutType::WITNESS_V1_TAPROOT:
return OutputType::BECH32M;
case TxoutType::WITNESS_V0_KEYHASH:
case TxoutType::WITNESS_V0_SCRIPTHASH:
if (is_from_p2sh) return OutputType::P2SH_SEGWIT;
else return OutputType::BECH32;
case TxoutType::SCRIPTHASH:
case TxoutType::PUBKEYHASH:
return OutputType::LEGACY;
default:
return OutputType::UNKNOWN;
}
}
// Fetch and validate the coin control selected inputs.
// Coins could be internal (from the wallet) or external.
util::Result<PreSelectedInputs> FetchSelectedInputs(const CWallet& wallet, const CCoinControl& coin_control,
const CoinSelectionParams& coin_selection_params) EXCLUSIVE_LOCKS_REQUIRED(wallet.cs_wallet)
{
PreSelectedInputs result;
const bool can_grind_r = wallet.CanGrindR();
for (const COutPoint& outpoint : coin_control.ListSelected()) {
int input_bytes = -1;
CTxOut txout;
if (auto ptr_wtx = wallet.GetWalletTx(outpoint.hash)) {
// Clearly invalid input, fail
if (ptr_wtx->tx->vout.size() <= outpoint.n) {
return util::Error{strprintf(_("Invalid pre-selected input %s"), outpoint.ToString())};
}
txout = ptr_wtx->tx->vout.at(outpoint.n);
input_bytes = CalculateMaximumSignedInputSize(txout, &wallet, &coin_control);
} else {
// The input is external. We did not find the tx in mapWallet.
const auto out{coin_control.GetExternalOutput(outpoint)};
if (!out) {
return util::Error{strprintf(_("Not found pre-selected input %s"), outpoint.ToString())};
}
txout = *out;
}
if (input_bytes == -1) {
input_bytes = CalculateMaximumSignedInputSize(txout, outpoint, &coin_control.m_external_provider, can_grind_r, &coin_control);
}
// If available, override calculated size with coin control specified size
if (coin_control.HasInputWeight(outpoint)) {
input_bytes = GetVirtualTransactionSize(coin_control.GetInputWeight(outpoint), 0, 0);
}
if (input_bytes == -1) {
return util::Error{strprintf(_("Not solvable pre-selected input %s"), outpoint.ToString())}; // Not solvable, can't estimate size for fee
}
/* Set some defaults for depth, spendable, solvable, safe, time, and from_me as these don't matter for preset inputs since no selection is being done. */
COutput output(outpoint, txout, /*depth=*/ 0, input_bytes, /*spendable=*/ true, /*solvable=*/ true, /*safe=*/ true, /*time=*/ 0, /*from_me=*/ false, coin_selection_params.m_effective_feerate);
result.Insert(output, coin_selection_params.m_subtract_fee_outputs);
}
return result;
}
CoinsResult AvailableCoins(const CWallet& wallet,
const CCoinControl* coinControl,
std::optional<CFeeRate> feerate,
const CoinFilterParams& params)
{
AssertLockHeld(wallet.cs_wallet);
CoinsResult result;
// Either the WALLET_FLAG_AVOID_REUSE flag is not set (in which case we always allow), or we default to avoiding, and only in the case where
// a coin control object is provided, and has the avoid address reuse flag set to false, do we allow already used addresses
bool allow_used_addresses = !wallet.IsWalletFlagSet(WALLET_FLAG_AVOID_REUSE) || (coinControl && !coinControl->m_avoid_address_reuse);
const int min_depth = {coinControl ? coinControl->m_min_depth : DEFAULT_MIN_DEPTH};
const int max_depth = {coinControl ? coinControl->m_max_depth : DEFAULT_MAX_DEPTH};
const bool only_safe = {coinControl ? !coinControl->m_include_unsafe_inputs : true};
const bool can_grind_r = wallet.CanGrindR();
std::set<uint256> trusted_parents;
for (const auto& entry : wallet.mapWallet)
{
const uint256& wtxid = entry.first;
const CWalletTx& wtx = entry.second;
if (wallet.IsTxImmatureCoinBase(wtx) && !params.include_immature_coinbase)
continue;
int nDepth = wallet.GetTxDepthInMainChain(wtx);
if (nDepth < 0)
continue;
// We should not consider coins which aren't at least in our mempool
// It's possible for these to be conflicted via ancestors which we may never be able to detect
if (nDepth == 0 && !wtx.InMempool())
continue;
bool safeTx = CachedTxIsTrusted(wallet, wtx, trusted_parents);
// We should not consider coins from transactions that are replacing
// other transactions.
//
// Example: There is a transaction A which is replaced by bumpfee
// transaction B. In this case, we want to prevent creation of
// a transaction B' which spends an output of B.
//
// Reason: If transaction A were initially confirmed, transactions B
// and B' would no longer be valid, so the user would have to create
// a new transaction C to replace B'. However, in the case of a
// one-block reorg, transactions B' and C might BOTH be accepted,
// when the user only wanted one of them. Specifically, there could
// be a 1-block reorg away from the chain where transactions A and C
// were accepted to another chain where B, B', and C were all
// accepted.
if (nDepth == 0 && wtx.mapValue.count("replaces_txid")) {
safeTx = false;
}
// Similarly, we should not consider coins from transactions that
// have been replaced. In the example above, we would want to prevent
// creation of a transaction A' spending an output of A, because if
// transaction B were initially confirmed, conflicting with A and
// A', we wouldn't want to the user to create a transaction D
// intending to replace A', but potentially resulting in a scenario
// where A, A', and D could all be accepted (instead of just B and
// D, or just A and A' like the user would want).
if (nDepth == 0 && wtx.mapValue.count("replaced_by_txid")) {
safeTx = false;
}
if (only_safe && !safeTx) {
continue;
}
if (nDepth < min_depth || nDepth > max_depth) {
continue;
}
bool tx_from_me = CachedTxIsFromMe(wallet, wtx, ISMINE_ALL);
for (unsigned int i = 0; i < wtx.tx->vout.size(); i++) {
const CTxOut& output = wtx.tx->vout[i];
const COutPoint outpoint(wtxid, i);
if (output.nValue < params.min_amount || output.nValue > params.max_amount)
continue;
// Skip manually selected coins (the caller can fetch them directly)
if (coinControl && coinControl->HasSelected() && coinControl->IsSelected(outpoint))
continue;
if (wallet.IsLockedCoin(outpoint) && params.skip_locked)
continue;
if (wallet.IsSpent(outpoint))
continue;
isminetype mine = wallet.IsMine(output);
if (mine == ISMINE_NO) {
continue;
}
if (!allow_used_addresses && wallet.IsSpentKey(output.scriptPubKey)) {
continue;
}
std::unique_ptr<SigningProvider> provider = wallet.GetSolvingProvider(output.scriptPubKey);
int input_bytes = CalculateMaximumSignedInputSize(output, COutPoint(), provider.get(), can_grind_r, coinControl);
bool solvable = provider ? InferDescriptor(output.scriptPubKey, *provider)->IsSolvable() : false;
bool spendable = ((mine & ISMINE_SPENDABLE) != ISMINE_NO) || (((mine & ISMINE_WATCH_ONLY) != ISMINE_NO) && (coinControl && coinControl->fAllowWatchOnly && solvable));
// Filter by spendable outputs only
if (!spendable && params.only_spendable) continue;
// Obtain script type
std::vector<std::vector<uint8_t>> script_solutions;
TxoutType type = Solver(output.scriptPubKey, script_solutions);
// If the output is P2SH and solvable, we want to know if it is
// a P2SH (legacy) or one of P2SH-P2WPKH, P2SH-P2WSH (P2SH-Segwit). We can determine
// this from the redeemScript. If the output is not solvable, it will be classified
// as a P2SH (legacy), since we have no way of knowing otherwise without the redeemScript
bool is_from_p2sh{false};
if (type == TxoutType::SCRIPTHASH && solvable) {
CScript script;
if (!provider->GetCScript(CScriptID(uint160(script_solutions[0])), script)) continue;
type = Solver(script, script_solutions);
is_from_p2sh = true;
}
result.Add(GetOutputType(type, is_from_p2sh),
COutput(outpoint, output, nDepth, input_bytes, spendable, solvable, safeTx, wtx.GetTxTime(), tx_from_me, feerate));
// Checks the sum amount of all UTXO's.
if (params.min_sum_amount != MAX_MONEY) {
if (result.GetTotalAmount() >= params.min_sum_amount) {
return result;
}
}
// Checks the maximum number of UTXO's.
if (params.max_count > 0 && result.Size() >= params.max_count) {
return result;
}
}
}
return result;
}
CoinsResult AvailableCoinsListUnspent(const CWallet& wallet, const CCoinControl* coinControl, CoinFilterParams params)
{
params.only_spendable = false;
return AvailableCoins(wallet, coinControl, /*feerate=*/ std::nullopt, params);
}
const CTxOut& FindNonChangeParentOutput(const CWallet& wallet, const COutPoint& outpoint)
{
AssertLockHeld(wallet.cs_wallet);
const CWalletTx* wtx{Assert(wallet.GetWalletTx(outpoint.hash))};
const CTransaction* ptx = wtx->tx.get();
int n = outpoint.n;
while (OutputIsChange(wallet, ptx->vout[n]) && ptx->vin.size() > 0) {
const COutPoint& prevout = ptx->vin[0].prevout;
const CWalletTx* it = wallet.GetWalletTx(prevout.hash);
if (!it || it->tx->vout.size() <= prevout.n ||
!wallet.IsMine(it->tx->vout[prevout.n])) {
break;
}
ptx = it->tx.get();
n = prevout.n;
}
return ptx->vout[n];
}
std::map<CTxDestination, std::vector<COutput>> ListCoins(const CWallet& wallet)
{
AssertLockHeld(wallet.cs_wallet);
std::map<CTxDestination, std::vector<COutput>> result;
CCoinControl coin_control;
// Include watch-only for LegacyScriptPubKeyMan wallets without private keys
coin_control.fAllowWatchOnly = wallet.GetLegacyScriptPubKeyMan() && wallet.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS);
CoinFilterParams coins_params;
coins_params.only_spendable = false;
coins_params.skip_locked = false;
for (const COutput& coin : AvailableCoins(wallet, &coin_control, /*feerate=*/std::nullopt, coins_params).All()) {
CTxDestination address;
if ((coin.spendable || (wallet.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS) && coin.solvable)) &&
ExtractDestination(FindNonChangeParentOutput(wallet, coin.outpoint).scriptPubKey, address)) {
result[address].emplace_back(coin);
}
}
return result;
}
FilteredOutputGroups GroupOutputs(const CWallet& wallet,
const CoinsResult& coins,
const CoinSelectionParams& coin_sel_params,
const std::vector<SelectionFilter>& filters,
std::vector<OutputGroup>& ret_discarded_groups)
{
FilteredOutputGroups filtered_groups;
if (!coin_sel_params.m_avoid_partial_spends) {
// Allowing partial spends means no grouping. Each COutput gets its own OutputGroup
for (const auto& [type, outputs] : coins.coins) {
for (const COutput& output : outputs) {
// Get mempool info
size_t ancestors, descendants;
wallet.chain().getTransactionAncestry(output.outpoint.hash, ancestors, descendants);
// Create a new group per output and add it to the all groups vector
OutputGroup group(coin_sel_params);
group.Insert(std::make_shared<COutput>(output), ancestors, descendants);
// Each filter maps to a different set of groups
bool accepted = false;
for (const auto& sel_filter : filters) {
const auto& filter = sel_filter.filter;
if (!group.EligibleForSpending(filter)) continue;
filtered_groups[filter].Push(group, type, /*insert_positive=*/true, /*insert_mixed=*/true);
accepted = true;
}
if (!accepted) ret_discarded_groups.emplace_back(group);
}
}
return filtered_groups;
}
// We want to combine COutputs that have the same scriptPubKey into single OutputGroups
// except when there are more than OUTPUT_GROUP_MAX_ENTRIES COutputs grouped in an OutputGroup.
// To do this, we maintain a map where the key is the scriptPubKey and the value is a vector of OutputGroups.
// For each COutput, we check if the scriptPubKey is in the map, and if it is, the COutput is added
// to the last OutputGroup in the vector for the scriptPubKey. When the last OutputGroup has
// OUTPUT_GROUP_MAX_ENTRIES COutputs, a new OutputGroup is added to the end of the vector.
typedef std::map<std::pair<CScript, OutputType>, std::vector<OutputGroup>> ScriptPubKeyToOutgroup;
const auto& insert_output = [&](
const std::shared_ptr<COutput>& output, OutputType type, size_t ancestors, size_t descendants,
ScriptPubKeyToOutgroup& groups_map) {
std::vector<OutputGroup>& groups = groups_map[std::make_pair(output->txout.scriptPubKey,type)];
if (groups.size() == 0) {
// No OutputGroups for this scriptPubKey yet, add one
groups.emplace_back(coin_sel_params);
}
// Get the last OutputGroup in the vector so that we can add the COutput to it
// A pointer is used here so that group can be reassigned later if it is full.
OutputGroup* group = &groups.back();
// Check if this OutputGroup is full. We limit to OUTPUT_GROUP_MAX_ENTRIES when using -avoidpartialspends
// to avoid surprising users with very high fees.
if (group->m_outputs.size() >= OUTPUT_GROUP_MAX_ENTRIES) {
// The last output group is full, add a new group to the vector and use that group for the insertion
groups.emplace_back(coin_sel_params);
group = &groups.back();
}
group->Insert(output, ancestors, descendants);
};
ScriptPubKeyToOutgroup spk_to_groups_map;
ScriptPubKeyToOutgroup spk_to_positive_groups_map;
for (const auto& [type, outs] : coins.coins) {
for (const COutput& output : outs) {
size_t ancestors, descendants;
wallet.chain().getTransactionAncestry(output.outpoint.hash, ancestors, descendants);
const auto& shared_output = std::make_shared<COutput>(output);
// Filter for positive only before adding the output
if (output.GetEffectiveValue() > 0) {
insert_output(shared_output, type, ancestors, descendants, spk_to_positive_groups_map);
}
// 'All' groups
insert_output(shared_output, type, ancestors, descendants, spk_to_groups_map);
}
}
// Now we go through the entire maps and pull out the OutputGroups
const auto& push_output_groups = [&](const ScriptPubKeyToOutgroup& groups_map, bool positive_only) {
for (const auto& [script, groups] : groups_map) {
// Go through the vector backwards. This allows for the first item we deal with being the partial group.
for (auto group_it = groups.rbegin(); group_it != groups.rend(); group_it++) {
const OutputGroup& group = *group_it;
// Each filter maps to a different set of groups
bool accepted = false;
for (const auto& sel_filter : filters) {
const auto& filter = sel_filter.filter;
if (!group.EligibleForSpending(filter)) continue;
// Don't include partial groups if there are full groups too and we don't want partial groups
if (group_it == groups.rbegin() && groups.size() > 1 && !filter.m_include_partial_groups) {
continue;
}
OutputType type = script.second;
// Either insert the group into the positive-only groups or the mixed ones.
filtered_groups[filter].Push(group, type, positive_only, /*insert_mixed=*/!positive_only);
accepted = true;
}
if (!accepted) ret_discarded_groups.emplace_back(group);
}
}
};
push_output_groups(spk_to_groups_map, /*positive_only=*/ false);
push_output_groups(spk_to_positive_groups_map, /*positive_only=*/ true);
return filtered_groups;
}
FilteredOutputGroups GroupOutputs(const CWallet& wallet,
const CoinsResult& coins,
const CoinSelectionParams& params,
const std::vector<SelectionFilter>& filters)
{
std::vector<OutputGroup> unused;
return GroupOutputs(wallet, coins, params, filters, unused);
}
// Returns true if the result contains an error and the message is not empty
static bool HasErrorMsg(const util::Result<SelectionResult>& res) { return !util::ErrorString(res).empty(); }
util::Result<SelectionResult> AttemptSelection(const CAmount& nTargetValue, OutputGroupTypeMap& groups,
const CoinSelectionParams& coin_selection_params, bool allow_mixed_output_types)
{
// Run coin selection on each OutputType and compute the Waste Metric
std::vector<SelectionResult> results;
for (auto& [type, group] : groups.groups_by_type) {
auto result{ChooseSelectionResult(nTargetValue, group, coin_selection_params)};
// If any specific error message appears here, then something particularly wrong happened.
if (HasErrorMsg(result)) return result; // So let's return the specific error.
// Append the favorable result.
if (result) results.push_back(*result);
}
// If we have at least one solution for funding the transaction without mixing, choose the minimum one according to waste metric
// and return the result
if (results.size() > 0) return *std::min_element(results.begin(), results.end());
// If we can't fund the transaction from any individual OutputType, run coin selection one last time
// over all available coins, which would allow mixing.
// If TypesCount() <= 1, there is nothing to mix.
if (allow_mixed_output_types && groups.TypesCount() > 1) {
return ChooseSelectionResult(nTargetValue, groups.all_groups, coin_selection_params);
}
// Either mixing is not allowed and we couldn't find a solution from any single OutputType, or mixing was allowed and we still couldn't
// find a solution using all available coins
return util::Error();
};
util::Result<SelectionResult> ChooseSelectionResult(const CAmount& nTargetValue, Groups& groups, const CoinSelectionParams& coin_selection_params)
{
// Vector of results. We will choose the best one based on waste.
std::vector<SelectionResult> results;
std::vector<util::Result<SelectionResult>> errors;
auto append_error = [&] (const util::Result<SelectionResult>& result) {
// If any specific error message appears here, then something different from a simple "no selection found" happened.
// Let's save it, so it can be retrieved to the user if no other selection algorithm succeeded.
if (HasErrorMsg(result)) {
errors.emplace_back(result);
}
};
// Maximum allowed weight
int max_inputs_weight = MAX_STANDARD_TX_WEIGHT - (coin_selection_params.tx_noinputs_size * WITNESS_SCALE_FACTOR);
if (auto bnb_result{SelectCoinsBnB(groups.positive_group, nTargetValue, coin_selection_params.m_cost_of_change, max_inputs_weight)}) {
results.push_back(*bnb_result);
} else append_error(bnb_result);
// As Knapsack and SRD can create change, also deduce change weight.
max_inputs_weight -= (coin_selection_params.change_output_size * WITNESS_SCALE_FACTOR);
// The knapsack solver has some legacy behavior where it will spend dust outputs. We retain this behavior, so don't filter for positive only here.
if (auto knapsack_result{KnapsackSolver(groups.mixed_group, nTargetValue, coin_selection_params.m_min_change_target, coin_selection_params.rng_fast, max_inputs_weight)}) {
knapsack_result->ComputeAndSetWaste(coin_selection_params.min_viable_change, coin_selection_params.m_cost_of_change, coin_selection_params.m_change_fee);
results.push_back(*knapsack_result);
} else append_error(knapsack_result);
if (auto srd_result{SelectCoinsSRD(groups.positive_group, nTargetValue, coin_selection_params.m_change_fee, coin_selection_params.rng_fast, max_inputs_weight)}) {
srd_result->ComputeAndSetWaste(coin_selection_params.min_viable_change, coin_selection_params.m_cost_of_change, coin_selection_params.m_change_fee);
results.push_back(*srd_result);
} else append_error(srd_result);
if (results.empty()) {
// No solution found, retrieve the first explicit error (if any).
// future: add 'severity level' to errors so the worst one can be retrieved instead of the first one.
return errors.empty() ? util::Error() : errors.front();
}
// Choose the result with the least waste
// If the waste is the same, choose the one which spends more inputs.
return *std::min_element(results.begin(), results.end());
}
util::Result<SelectionResult> SelectCoins(const CWallet& wallet, CoinsResult& available_coins, const PreSelectedInputs& pre_set_inputs,
const CAmount& nTargetValue, const CCoinControl& coin_control,
const CoinSelectionParams& coin_selection_params)
{
// Deduct preset inputs amount from the search target
CAmount selection_target = nTargetValue - pre_set_inputs.total_amount;
// Return if automatic coin selection is disabled, and we don't cover the selection target
if (!coin_control.m_allow_other_inputs && selection_target > 0) {
return util::Error{_("The preselected coins total amount does not cover the transaction target. "
"Please allow other inputs to be automatically selected or include more coins manually")};
}
// Return if we can cover the target only with the preset inputs
if (selection_target <= 0) {
SelectionResult result(nTargetValue, SelectionAlgorithm::MANUAL);
result.AddInputs(pre_set_inputs.coins, coin_selection_params.m_subtract_fee_outputs);
result.ComputeAndSetWaste(coin_selection_params.min_viable_change, coin_selection_params.m_cost_of_change, coin_selection_params.m_change_fee);
return result;
}
// Return early if we cannot cover the target with the wallet's UTXO.
// We use the total effective value if we are not subtracting fee from outputs and 'available_coins' contains the data.
CAmount available_coins_total_amount = coin_selection_params.m_subtract_fee_outputs ? available_coins.GetTotalAmount() :
(available_coins.GetEffectiveTotalAmount().has_value() ? *available_coins.GetEffectiveTotalAmount() : 0);
if (selection_target > available_coins_total_amount) {
return util::Error(); // Insufficient funds
}
// Start wallet Coin Selection procedure
auto op_selection_result = AutomaticCoinSelection(wallet, available_coins, selection_target, coin_selection_params);
if (!op_selection_result) return op_selection_result;
// If needed, add preset inputs to the automatic coin selection result
if (!pre_set_inputs.coins.empty()) {
SelectionResult preselected(pre_set_inputs.total_amount, SelectionAlgorithm::MANUAL);
preselected.AddInputs(pre_set_inputs.coins, coin_selection_params.m_subtract_fee_outputs);
op_selection_result->Merge(preselected);
op_selection_result->ComputeAndSetWaste(coin_selection_params.min_viable_change,
coin_selection_params.m_cost_of_change,
coin_selection_params.m_change_fee);
}
return op_selection_result;
}
util::Result<SelectionResult> AutomaticCoinSelection(const CWallet& wallet, CoinsResult& available_coins, const CAmount& value_to_select, const CoinSelectionParams& coin_selection_params)
{
unsigned int limit_ancestor_count = 0;
unsigned int limit_descendant_count = 0;
wallet.chain().getPackageLimits(limit_ancestor_count, limit_descendant_count);
const size_t max_ancestors = (size_t)std::max<int64_t>(1, limit_ancestor_count);
const size_t max_descendants = (size_t)std::max<int64_t>(1, limit_descendant_count);
const bool fRejectLongChains = gArgs.GetBoolArg("-walletrejectlongchains", DEFAULT_WALLET_REJECT_LONG_CHAINS);
// Cases where we have 101+ outputs all pointing to the same destination may result in
// privacy leaks as they will potentially be deterministically sorted. We solve that by
// explicitly shuffling the outputs before processing
if (coin_selection_params.m_avoid_partial_spends && available_coins.Size() > OUTPUT_GROUP_MAX_ENTRIES) {
available_coins.Shuffle(coin_selection_params.rng_fast);
}
// Coin Selection attempts to select inputs from a pool of eligible UTXOs to fund the
// transaction at a target feerate. If an attempt fails, more attempts may be made using a more
// permissive CoinEligibilityFilter.
util::Result<SelectionResult> res = [&] {
// Place coins eligibility filters on a scope increasing order.
std::vector<SelectionFilter> ordered_filters{
// If possible, fund the transaction with confirmed UTXOs only. Prefer at least six
// confirmations on outputs received from other wallets and only spend confirmed change.
{CoinEligibilityFilter(1, 6, 0), /*allow_mixed_output_types=*/false},
{CoinEligibilityFilter(1, 1, 0)},
};
// Fall back to using zero confirmation change (but with as few ancestors in the mempool as
// possible) if we cannot fund the transaction otherwise.
if (wallet.m_spend_zero_conf_change) {
ordered_filters.push_back({CoinEligibilityFilter(0, 1, 2)});
ordered_filters.push_back({CoinEligibilityFilter(0, 1, std::min(size_t{4}, max_ancestors/3), std::min(size_t{4}, max_descendants/3))});
ordered_filters.push_back({CoinEligibilityFilter(0, 1, max_ancestors/2, max_descendants/2)});
// If partial groups are allowed, relax the requirement of spending OutputGroups (groups
// of UTXOs sent to the same address, which are obviously controlled by a single wallet)
// in their entirety.
ordered_filters.push_back({CoinEligibilityFilter(0, 1, max_ancestors-1, max_descendants-1, /*include_partial=*/true)});
// Try with unsafe inputs if they are allowed. This may spend unconfirmed outputs
// received from other wallets.
if (coin_selection_params.m_include_unsafe_inputs) {
ordered_filters.push_back({CoinEligibilityFilter(/*conf_mine=*/0, /*conf_theirs*/0, max_ancestors-1, max_descendants-1, /*include_partial=*/true)});
}
// Try with unlimited ancestors/descendants. The transaction will still need to meet
// mempool ancestor/descendant policy to be accepted to mempool and broadcasted, but
// OutputGroups use heuristics that may overestimate ancestor/descendant counts.
if (!fRejectLongChains) {
ordered_filters.push_back({CoinEligibilityFilter(0, 1, std::numeric_limits<uint64_t>::max(),
std::numeric_limits<uint64_t>::max(),
/*include_partial=*/true)});
}
}
// Group outputs and map them by coin eligibility filter
std::vector<OutputGroup> discarded_groups;
FilteredOutputGroups filtered_groups = GroupOutputs(wallet, available_coins, coin_selection_params, ordered_filters, discarded_groups);
// Check if we still have enough balance after applying filters (some coins might be discarded)
CAmount total_discarded = 0;
CAmount total_unconf_long_chain = 0;
for (const auto& group : discarded_groups) {
total_discarded += group.GetSelectionAmount();
if (group.m_ancestors >= max_ancestors || group.m_descendants >= max_descendants) total_unconf_long_chain += group.GetSelectionAmount();
}
if (CAmount total_amount = available_coins.GetTotalAmount() - total_discarded < value_to_select) {
// Special case, too-long-mempool cluster.
if (total_amount + total_unconf_long_chain > value_to_select) {
return util::Result<SelectionResult>({_("Unconfirmed UTXOs are available, but spending them creates a chain of transactions that will be rejected by the mempool")});
}
return util::Result<SelectionResult>(util::Error()); // General "Insufficient Funds"
}
// Walk-through the filters until the solution gets found.
// If no solution is found, return the first detailed error (if any).
// future: add "error level" so the worst one can be picked instead.
std::vector<util::Result<SelectionResult>> res_detailed_errors;
for (const auto& select_filter : ordered_filters) {
auto it = filtered_groups.find(select_filter.filter);
if (it == filtered_groups.end()) continue;
if (auto res{AttemptSelection(value_to_select, it->second,
coin_selection_params, select_filter.allow_mixed_output_types)}) {
return res; // result found
} else {
// If any specific error message appears here, then something particularly wrong might have happened.
// Save the error and continue the selection process. So if no solutions gets found, we can return
// the detailed error to the upper layers.
if (HasErrorMsg(res)) res_detailed_errors.emplace_back(res);
}
}
// Return right away if we have a detailed error
if (!res_detailed_errors.empty()) return res_detailed_errors.front();
// General "Insufficient Funds"
return util::Result<SelectionResult>(util::Error());
}();
return res;
}
static bool IsCurrentForAntiFeeSniping(interfaces::Chain& chain, const uint256& block_hash)
{
if (chain.isInitialBlockDownload()) {
return false;
}
constexpr int64_t MAX_ANTI_FEE_SNIPING_TIP_AGE = 8 * 60 * 60; // in seconds
int64_t block_time;
CHECK_NONFATAL(chain.findBlock(block_hash, FoundBlock().time(block_time)));
if (block_time < (GetTime() - MAX_ANTI_FEE_SNIPING_TIP_AGE)) {
return false;
}
return true;
}
/**
* Set a height-based locktime for new transactions (uses the height of the
* current chain tip unless we are not synced with the current chain
*/
static void DiscourageFeeSniping(CMutableTransaction& tx, FastRandomContext& rng_fast,
interfaces::Chain& chain, const uint256& block_hash, int block_height)
{
// All inputs must be added by now
assert(!tx.vin.empty());
// Discourage fee sniping.
//
// For a large miner the value of the transactions in the best block and
// the mempool can exceed the cost of deliberately attempting to mine two
// blocks to orphan the current best block. By setting nLockTime such that
// only the next block can include the transaction, we discourage this
// practice as the height restricted and limited blocksize gives miners
// considering fee sniping fewer options for pulling off this attack.
//
// A simple way to think about this is from the wallet's point of view we
// always want the blockchain to move forward. By setting nLockTime this
// way we're basically making the statement that we only want this
// transaction to appear in the next block; we don't want to potentially
// encourage reorgs by allowing transactions to appear at lower heights
// than the next block in forks of the best chain.
//
// Of course, the subsidy is high enough, and transaction volume low
// enough, that fee sniping isn't a problem yet, but by implementing a fix
// now we ensure code won't be written that makes assumptions about
// nLockTime that preclude a fix later.
if (IsCurrentForAntiFeeSniping(chain, block_hash)) {
tx.nLockTime = block_height;
// Secondly occasionally randomly pick a nLockTime even further back, so
// that transactions that are delayed after signing for whatever reason,
// e.g. high-latency mix networks and some CoinJoin implementations, have
// better privacy.
if (rng_fast.randrange(10) == 0) {
tx.nLockTime = std::max(0, int(tx.nLockTime) - int(rng_fast.randrange(100)));
}
} else {
// If our chain is lagging behind, we can't discourage fee sniping nor help
// the privacy of high-latency transactions. To avoid leaking a potentially
// unique "nLockTime fingerprint", set nLockTime to a constant.
tx.nLockTime = 0;
}
// Sanity check all values
assert(tx.nLockTime < LOCKTIME_THRESHOLD); // Type must be block height
assert(tx.nLockTime <= uint64_t(block_height));
for (const auto& in : tx.vin) {
// Can not be FINAL for locktime to work
assert(in.nSequence != CTxIn::SEQUENCE_FINAL);
// May be MAX NONFINAL to disable both BIP68 and BIP125
if (in.nSequence == CTxIn::MAX_SEQUENCE_NONFINAL) continue;
// May be MAX BIP125 to disable BIP68 and enable BIP125
if (in.nSequence == MAX_BIP125_RBF_SEQUENCE) continue;
// The wallet does not support any other sequence-use right now.
assert(false);
}
}
static util::Result<CreatedTransactionResult> CreateTransactionInternal(
CWallet& wallet,
const std::vector<CRecipient>& vecSend,
int change_pos,
const CCoinControl& coin_control,
bool sign) EXCLUSIVE_LOCKS_REQUIRED(wallet.cs_wallet)
{
AssertLockHeld(wallet.cs_wallet);
// out variables, to be packed into returned result structure
int nChangePosInOut = change_pos;
FastRandomContext rng_fast;
CMutableTransaction txNew; // The resulting transaction that we make
CoinSelectionParams coin_selection_params{rng_fast}; // Parameters for coin selection, init with dummy
coin_selection_params.m_avoid_partial_spends = coin_control.m_avoid_partial_spends;
coin_selection_params.m_include_unsafe_inputs = coin_control.m_include_unsafe_inputs;
// Set the long term feerate estimate to the wallet's consolidate feerate
coin_selection_params.m_long_term_feerate = wallet.m_consolidate_feerate;
CAmount recipients_sum = 0;
const OutputType change_type = wallet.TransactionChangeType(coin_control.m_change_type ? *coin_control.m_change_type : wallet.m_default_change_type, vecSend);
ReserveDestination reservedest(&wallet, change_type);
unsigned int outputs_to_subtract_fee_from = 0; // The number of outputs which we are subtracting the fee from
for (const auto& recipient : vecSend) {
recipients_sum += recipient.nAmount;
if (recipient.fSubtractFeeFromAmount) {
outputs_to_subtract_fee_from++;
coin_selection_params.m_subtract_fee_outputs = true;
}
}
// Create change script that will be used if we need change
CScript scriptChange;
bilingual_str error; // possible error str
// coin control: send change to custom address
if (!std::get_if<CNoDestination>(&coin_control.destChange)) {
scriptChange = GetScriptForDestination(coin_control.destChange);
} else { // no coin control: send change to newly generated address
// Note: We use a new key here to keep it from being obvious which side is the change.
// The drawback is that by not reusing a previous key, the change may be lost if a
// backup is restored, if the backup doesn't have the new private key for the change.
// If we reused the old key, it would be possible to add code to look for and
// rediscover unknown transactions that were written with keys of ours to recover
// post-backup change.
// Reserve a new key pair from key pool. If it fails, provide a dummy
// destination in case we don't need change.
CTxDestination dest;
auto op_dest = reservedest.GetReservedDestination(true);
if (!op_dest) {
error = _("Transaction needs a change address, but we can't generate it.") + Untranslated(" ") + util::ErrorString(op_dest);
} else {
dest = *op_dest;
scriptChange = GetScriptForDestination(dest);
}
// A valid destination implies a change script (and
// vice-versa). An empty change script will abort later, if the
// change keypool ran out, but change is required.
CHECK_NONFATAL(IsValidDestination(dest) != scriptChange.empty());
}
CTxOut change_prototype_txout(0, scriptChange);
coin_selection_params.change_output_size = GetSerializeSize(change_prototype_txout);
// Get size of spending the change output
int change_spend_size = CalculateMaximumSignedInputSize(change_prototype_txout, &wallet, /*coin_control=*/nullptr);
// If the wallet doesn't know how to sign change output, assume p2sh-p2wpkh
// as lower-bound to allow BnB to do it's thing
if (change_spend_size == -1) {
coin_selection_params.change_spend_size = DUMMY_NESTED_P2WPKH_INPUT_SIZE;
} else {
coin_selection_params.change_spend_size = (size_t)change_spend_size;
}
// Set discard feerate
coin_selection_params.m_discard_feerate = GetDiscardRate(wallet);
// Get the fee rate to use effective values in coin selection
FeeCalculation feeCalc;
coin_selection_params.m_effective_feerate = GetMinimumFeeRate(wallet, coin_control, &feeCalc);
// Do not, ever, assume that it's fine to change the fee rate if the user has explicitly
// provided one
if (coin_control.m_feerate && coin_selection_params.m_effective_feerate > *coin_control.m_feerate) {
return util::Error{strprintf(_("Fee rate (%s) is lower than the minimum fee rate setting (%s)"), coin_control.m_feerate->ToString(FeeEstimateMode::SAT_VB), coin_selection_params.m_effective_feerate.ToString(FeeEstimateMode::SAT_VB))};
}
if (feeCalc.reason == FeeReason::FALLBACK && !wallet.m_allow_fallback_fee) {
// eventually allow a fallback fee
return util::Error{strprintf(_("Fee estimation failed. Fallbackfee is disabled. Wait a few blocks or enable %s."), "-fallbackfee")};
}
// Calculate the cost of change
// Cost of change is the cost of creating the change output + cost of spending the change output in the future.
// For creating the change output now, we use the effective feerate.
// For spending the change output in the future, we use the discard feerate for now.
// So cost of change = (change output size * effective feerate) + (size of spending change output * discard feerate)
coin_selection_params.m_change_fee = coin_selection_params.m_effective_feerate.GetFee(coin_selection_params.change_output_size);
coin_selection_params.m_cost_of_change = coin_selection_params.m_discard_feerate.GetFee(coin_selection_params.change_spend_size) + coin_selection_params.m_change_fee;
coin_selection_params.m_min_change_target = GenerateChangeTarget(std::floor(recipients_sum / vecSend.size()), coin_selection_params.m_change_fee, rng_fast);
// The smallest change amount should be:
// 1. at least equal to dust threshold
// 2. at least 1 sat greater than fees to spend it at m_discard_feerate
const auto dust = GetDustThreshold(change_prototype_txout, coin_selection_params.m_discard_feerate);
const auto change_spend_fee = coin_selection_params.m_discard_feerate.GetFee(coin_selection_params.change_spend_size);
coin_selection_params.min_viable_change = std::max(change_spend_fee + 1, dust);
// Static vsize overhead + outputs vsize. 4 nVersion, 4 nLocktime, 1 input count, 1 witness overhead (dummy, flag, stack size)
coin_selection_params.tx_noinputs_size = 10 + GetSizeOfCompactSize(vecSend.size()); // bytes for output count
// vouts to the payees
for (const auto& recipient : vecSend)
{
CTxOut txout(recipient.nAmount, recipient.scriptPubKey);
// Include the fee cost for outputs.
coin_selection_params.tx_noinputs_size += ::GetSerializeSize(txout, PROTOCOL_VERSION);
if (IsDust(txout, wallet.chain().relayDustFee())) {
return util::Error{_("Transaction amount too small")};
}
txNew.vout.push_back(txout);
}
// Include the fees for things that aren't inputs, excluding the change output
const CAmount not_input_fees = coin_selection_params.m_effective_feerate.GetFee(coin_selection_params.m_subtract_fee_outputs ? 0 : coin_selection_params.tx_noinputs_size);
CAmount selection_target = recipients_sum + not_input_fees;
// This can only happen if feerate is 0, and requested destinations are value of 0 (e.g. OP_RETURN)
// and no pre-selected inputs. This will result in 0-input transaction, which is consensus-invalid anyways
if (selection_target == 0 && !coin_control.HasSelected()) {
return util::Error{_("Transaction requires one destination of non-0 value, a non-0 feerate, or a pre-selected input")};
}
// Fetch manually selected coins
PreSelectedInputs preset_inputs;
if (coin_control.HasSelected()) {
auto res_fetch_inputs = FetchSelectedInputs(wallet, coin_control, coin_selection_params);
if (!res_fetch_inputs) return util::Error{util::ErrorString(res_fetch_inputs)};
preset_inputs = *res_fetch_inputs;
}
// Fetch wallet available coins if "other inputs" are
// allowed (coins automatically selected by the wallet)
CoinsResult available_coins;
if (coin_control.m_allow_other_inputs) {
available_coins = AvailableCoins(wallet, &coin_control, coin_selection_params.m_effective_feerate);
}
// Choose coins to use
auto select_coins_res = SelectCoins(wallet, available_coins, preset_inputs, /*nTargetValue=*/selection_target, coin_control, coin_selection_params);
if (!select_coins_res) {
// 'SelectCoins' either returns a specific error message or, if empty, means a general "Insufficient funds".
const bilingual_str& err = util::ErrorString(select_coins_res);
return util::Error{err.empty() ?_("Insufficient funds") : err};
}
const SelectionResult& result = *select_coins_res;
TRACE5(coin_selection, selected_coins, wallet.GetName().c_str(), GetAlgorithmName(result.GetAlgo()).c_str(), result.GetTarget(), result.GetWaste(), result.GetSelectedValue());
const CAmount change_amount = result.GetChange(coin_selection_params.min_viable_change, coin_selection_params.m_change_fee);
if (change_amount > 0) {
CTxOut newTxOut(change_amount, scriptChange);
if (nChangePosInOut == -1) {
// Insert change txn at random position:
nChangePosInOut = rng_fast.randrange(txNew.vout.size() + 1);
} else if ((unsigned int)nChangePosInOut > txNew.vout.size()) {
return util::Error{_("Transaction change output index out of range")};
}
txNew.vout.insert(txNew.vout.begin() + nChangePosInOut, newTxOut);
} else {
nChangePosInOut = -1;
}
// Shuffle selected coins and fill in final vin
std::vector<std::shared_ptr<COutput>> selected_coins = result.GetShuffledInputVector();