-
Notifications
You must be signed in to change notification settings - Fork 388
/
Copy pathspend.cpp
1863 lines (1647 loc) · 87.1 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 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 <blind.h> // ELEMENTS: for MAX_RANGEPROOF_SIZE
#include <consensus/amount.h>
#include <consensus/validation.h>
#include <interfaces/chain.h>
#include <issuance.h> // ELEMENTS: for GenerateAssetEntropy and others
#include <policy/policy.h>
#include <rpc/util.h> // for GetDestinationBlindingKey and IsBlindDestination
#include <script/signingprovider.h>
#include <util/check.h>
#include <util/fees.h>
#include <util/moneystr.h>
#include <util/rbf.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>
using interfaces::FoundBlock;
namespace wallet {
static constexpr size_t OUTPUT_GROUP_MAX_ENTRIES{100};
int GetTxSpendSize(const CWallet& wallet, const CWalletTx& wtx, unsigned int out, bool use_max_sig)
{
return CalculateMaximumSignedInputSize(wtx.tx->vout[out], &wallet, use_max_sig);
}
std::string COutput::ToString(const CWallet& wallet) const
{
return strprintf("COutput(%s, %d, %d) [%s] [%s]", tx->GetHash().ToString(), i, nDepth, FormatMoney(tx->GetOutputValueOut(wallet, i)), tx->GetOutputAsset(wallet, i).GetHex());
}
// Helper for producing a max-sized low-S low-R signature (eg 71 bytes)
// or a max-sized low-S signature (e.g. 72 bytes) if use_max_sig is true
bool DummySignInput(const SigningProvider& provider, CMutableTransaction& tx, const size_t nIn, const CTxOut& txout, bool use_max_sig)
{
// Fill in dummy signatures for fee calculation.
const CScript& scriptPubKey = txout.scriptPubKey;
SignatureData sigdata;
if (!ProduceSignature(provider, use_max_sig ? DUMMY_MAXIMUM_SIGNATURE_CREATOR : DUMMY_SIGNATURE_CREATOR, scriptPubKey, sigdata)) {
return false;
}
UpdateTransaction(tx, nIn, sigdata);
return true;
}
// Helper for producing a bunch of max-sized low-S low-R signatures (eg 71 bytes)
bool CWallet::DummySignTx(CMutableTransaction &txNew, const std::vector<CTxOut> &txouts, const CCoinControl* coin_control) const
{
// Fill in dummy signatures for fee calculation.
int nIn = 0;
for (const auto& txout : txouts)
{
CTxIn& txin = txNew.vin[nIn];
// If weight was provided, fill the input to that weight
if (coin_control && coin_control->HasInputWeight(txin.prevout)) {
if (!FillInputToWeight(txNew, nIn, coin_control->GetInputWeight(txin.prevout))) {
return false;
}
nIn++;
continue;
}
// Use max sig if watch only inputs were used or if this particular input is an external input
// to ensure a sufficient fee is attained for the requested feerate.
const bool use_max_sig = coin_control && (coin_control->fAllowWatchOnly || coin_control->IsExternalSelected(txin.prevout));
const std::unique_ptr<SigningProvider> provider = GetSolvingProvider(txout.scriptPubKey);
if (!provider || !DummySignInput(*provider, txNew, nIn, txout, use_max_sig)) {
if (!coin_control || !DummySignInput(coin_control->m_external_provider, txNew, nIn, txout, use_max_sig)) {
return false;
}
}
nIn++;
}
return true;
}
bool FillInputToWeight(CMutableTransaction& mtx, size_t nIn, int64_t target_weight)
{
assert(mtx.vin[nIn].scriptSig.empty());
assert(mtx.witness.vtxinwit[nIn].scriptWitness.IsNull());
int64_t txin_weight = GetTransactionInputWeight(CTransaction(mtx), nIn);
// Do nothing if the weight that should be added is less than the weight that already exists
if (target_weight < txin_weight) {
return false;
}
if (target_weight == txin_weight) {
return true;
}
// Subtract current txin weight, which should include empty witness stack
int64_t add_weight = target_weight - txin_weight;
assert(add_weight > 0);
// We will want to subtract the size of the Compact Size UInt that will also be serialized.
// However doing so when the size is near a boundary can result in a problem where it is not
// possible to have a stack element size and combination to exactly equal a target.
// To avoid this possibility, if the weight to add is less than 10 bytes greater than
// a boundary, the size will be split so that 2/3rds will be in one stack element, and
// the remaining 1/3rd in another. Using 3rds allows us to avoid additional boundaries.
// 10 bytes is used because that accounts for the maximum size. This does not need to be super precise.
if ((add_weight >= 253 && add_weight < 263)
|| (add_weight > std::numeric_limits<uint16_t>::max() && add_weight <= std::numeric_limits<uint16_t>::max() + 10)
|| (add_weight > std::numeric_limits<uint32_t>::max() && add_weight <= std::numeric_limits<uint32_t>::max() + 10)) {
int64_t first_weight = add_weight / 3;
add_weight -= first_weight;
first_weight -= GetSizeOfCompactSize(first_weight);
mtx.witness.vtxinwit[nIn].scriptWitness.stack.emplace(mtx.witness.vtxinwit[nIn].scriptWitness.stack.end(), first_weight, 0);
}
add_weight -= GetSizeOfCompactSize(add_weight);
mtx.witness.vtxinwit[nIn].scriptWitness.stack.emplace(mtx.witness.vtxinwit[nIn].scriptWitness.stack.end(), add_weight, 0);
assert(GetTransactionInputWeight(CTransaction(mtx), nIn) == target_weight);
return true;
}
int CalculateMaximumSignedInputSize(const CTxOut& txout, const SigningProvider* provider, bool use_max_sig) {
CMutableTransaction txn;
txn.vin.push_back(CTxIn(COutPoint()));
if (!provider || !DummySignInput(*provider, txn, 0, txout, use_max_sig)) {
return -1;
}
return GetVirtualTransactionInputSize(CTransaction(txn));
}
int CalculateMaximumSignedInputSize(const CTxOut& txout, const CWallet* wallet, bool use_max_sig)
{
const std::unique_ptr<SigningProvider> provider = wallet->GetSolvingProvider(txout.scriptPubKey);
return CalculateMaximumSignedInputSize(txout, provider.get(), use_max_sig);
}
// Returns pair of vsize and weight
TxSize CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet, const CCoinControl* coin_control) EXCLUSIVE_LOCKS_REQUIRED(wallet->cs_wallet)
{
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);
if (mi != wallet->mapWallet.end()) {
assert(input.prevout.n < mi->second.tx->vout.size());
txouts.emplace_back(mi->second.tx->vout[input.prevout.n]);
} else if (coin_control) {
CTxOut txout;
if (!coin_control->GetExternalOutput(input.prevout, txout)) {
return TxSize{-1, -1};
}
txouts.emplace_back(txout);
} else {
return TxSize{-1, -1};
}
}
return CalculateMaximumSignedTxSize(tx, wallet, txouts, 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);
// ELEMENTS: use discounted vsize for CTs if enabled
if (Params().GetCreateDiscountCT()) {
vsize = GetDiscountVirtualTransactionSize(ctx);
}
return TxSize{vsize, weight};
}
void AvailableCoins(const CWallet& wallet, std::vector<COutput> &vCoins, const CCoinControl *coinControl, const CAmount &nMinimumAmount, const CAmount &nMaximumAmount, const CAmount &nMinimumSumAmount, const uint64_t nMaximumCount, const CAsset* asset_filter) EXCLUSIVE_LOCKS_REQUIRED(wallet.cs_wallet)
{
AssertLockHeld(wallet.cs_wallet);
vCoins.clear();
CAmount nTotal = 0;
// 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};
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))
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;
}
for (unsigned int i = 0; i < wtx.tx->vout.size(); i++) {
// Only consider selected coins if add_inputs is false
if (coinControl && !coinControl->m_add_inputs && !coinControl->IsSelected(COutPoint(entry.first, i))) {
continue;
}
CAmount outValue = wtx.GetOutputValueOut(wallet, i);
CAsset asset = wtx.GetOutputAsset(wallet, i);
if (asset_filter && asset != *asset_filter) {
continue;
}
if (outValue < nMinimumAmount || (asset == Params().GetConsensus().pegged_asset && outValue > nMaximumAmount)) {
continue;
}
if (coinControl && coinControl->HasSelected() && !coinControl->fAllowOtherInputs && !coinControl->IsSelected(COutPoint(entry.first, i)))
continue;
if (wallet.IsLockedCoin(entry.first, i))
continue;
if (wallet.IsSpent(wtxid, i))
continue;
isminetype mine = wallet.IsMine(wtx.tx->vout[i]);
if (mine == ISMINE_NO) {
continue;
}
if (!allow_used_addresses && wallet.IsSpentKey(wtxid, i)) {
continue;
}
std::unique_ptr<SigningProvider> provider = wallet.GetSolvingProvider(wtx.tx->vout[i].scriptPubKey);
bool solvable = provider ? IsSolvable(*provider, wtx.tx->vout[i].scriptPubKey) : false;
bool spendable = ((mine & ISMINE_SPENDABLE) != ISMINE_NO) || (((mine & ISMINE_WATCH_ONLY) != ISMINE_NO) && (coinControl && coinControl->fAllowWatchOnly && solvable));
vCoins.push_back(COutput(wallet, wtx, i, nDepth, spendable, solvable, safeTx, (coinControl && coinControl->fAllowWatchOnly)));
// Checks the sum amount of all UTXO's.
if (nMinimumSumAmount != MAX_MONEY) {
nTotal += outValue;
if (nTotal >= nMinimumSumAmount) {
return;
}
}
// Checks the maximum number of UTXO's.
if (nMaximumCount > 0 && vCoins.size() >= nMaximumCount) {
return;
}
}
}
}
CAmountMap GetAvailableBalance(const CWallet& wallet, const CCoinControl* coinControl)
{
LOCK(wallet.cs_wallet);
CAmountMap balance;
std::vector<COutput> vCoins;
AvailableCoins(wallet, vCoins, coinControl);
for (const COutput& out : vCoins) {
if (out.fSpendable) {
CAmount amt = out.tx->GetOutputValueOut(wallet, out.i);
if (amt < 0) {
continue;
}
balance[out.tx->GetOutputAsset(wallet, out.i)] += amt;
}
}
return balance;
}
const CTxOut& FindNonChangeParentOutput(const CWallet& wallet, const CTransaction& tx, int output) EXCLUSIVE_LOCKS_REQUIRED(wallet.cs_wallet)
{
AssertLockHeld(wallet.cs_wallet);
const CTransaction* ptx = &tx;
int n = output;
while (OutputIsChange(wallet, ptx->vout[n]) && ptx->vin.size() > 0) {
const COutPoint& prevout = ptx->vin[0].prevout;
auto it = wallet.mapWallet.find(prevout.hash);
if (it == wallet.mapWallet.end() || it->second.tx->vout.size() <= prevout.n ||
!wallet.IsMine(it->second.tx->vout[prevout.n])) {
break;
}
ptx = it->second.tx.get();
n = prevout.n;
}
return ptx->vout[n];
}
std::map<CTxDestination, std::vector<COutput>> ListCoins(const CWallet& wallet) EXCLUSIVE_LOCKS_REQUIRED(wallet.cs_wallet)
{
AssertLockHeld(wallet.cs_wallet);
std::map<CTxDestination, std::vector<COutput>> result;
std::vector<COutput> availableCoins;
AvailableCoins(wallet, availableCoins);
for (const COutput& coin : availableCoins) {
CTxDestination address;
if ((coin.fSpendable || (wallet.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS) && coin.fSolvable)) &&
ExtractDestination(FindNonChangeParentOutput(wallet, *coin.tx->tx, coin.i).scriptPubKey, address)) {
result[address].emplace_back(std::move(coin));
}
}
std::vector<COutPoint> lockedCoins;
wallet.ListLockedCoins(lockedCoins);
// Include watch-only for LegacyScriptPubKeyMan wallets without private keys
const bool include_watch_only = wallet.GetLegacyScriptPubKeyMan() && wallet.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS);
const isminetype is_mine_filter = include_watch_only ? ISMINE_WATCH_ONLY : ISMINE_SPENDABLE;
for (const COutPoint& output : lockedCoins) {
auto it = wallet.mapWallet.find(output.hash);
if (it != wallet.mapWallet.end()) {
int depth = wallet.GetTxDepthInMainChain(it->second);
if (depth >= 0 && output.n < it->second.tx->vout.size() &&
wallet.IsMine(it->second.tx->vout[output.n]) == is_mine_filter
) {
CTxDestination address;
if (ExtractDestination(FindNonChangeParentOutput(wallet, *it->second.tx, output.n).scriptPubKey, address)) {
result[address].emplace_back(
wallet, it->second, output.n, depth, true /* spendable */, true /* solvable */, false /* safe */);
}
}
}
}
return result;
}
std::vector<OutputGroup> GroupOutputs(const CWallet& wallet, const std::vector<COutput>& outputs, const CoinSelectionParams& coin_sel_params, const CoinEligibilityFilter& filter, bool positive_only)
{
std::vector<OutputGroup> groups_out;
if (!coin_sel_params.m_avoid_partial_spends) {
// Allowing partial spends means no grouping. Each COutput gets its own OutputGroup.
for (const COutput& output : outputs) {
// Skip outputs we cannot spend
if (!output.fSpendable) continue;
size_t ancestors, descendants;
wallet.chain().getTransactionAncestry(output.tx->GetHash(), ancestors, descendants);
CInputCoin input_coin = output.GetInputCoin(wallet);
// Make an OutputGroup containing just this output
OutputGroup group{coin_sel_params};
group.Insert(input_coin, output.nDepth, CachedTxIsFromMe(wallet, *output.tx, ISMINE_ALL), ancestors, descendants, positive_only);
// Check the OutputGroup's eligibility. Only add the eligible ones.
if (positive_only && group.GetSelectionAmount() <= 0) continue;
if (group.m_outputs.size() > 0 && group.EligibleForSpending(filter)) groups_out.push_back(group);
}
return groups_out;
}
// 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's CInputCoin is added
// to the last OutputGroup in the vector for the scriptPubKey. When the last OutputGroup has
// OUTPUT_GROUP_MAX_ENTRIES CInputCoins, a new OutputGroup is added to the end of the vector.
std::map<CScript, std::vector<OutputGroup>> spk_to_groups_map;
for (const auto& output : outputs) {
// Skip outputs we cannot spend
if (!output.fSpendable) continue;
size_t ancestors, descendants;
wallet.chain().getTransactionAncestry(output.tx->GetHash(), ancestors, descendants);
CInputCoin input_coin = output.GetInputCoin(wallet);
CScript spk = input_coin.txout.scriptPubKey;
std::vector<OutputGroup>& groups = spk_to_groups_map[spk];
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 CInputCoin 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();
}
// Add the input_coin to group
group->Insert(input_coin, output.nDepth, CachedTxIsFromMe(wallet, *output.tx, ISMINE_ALL), ancestors, descendants, positive_only);
}
// Now we go through the entire map and pull out the OutputGroups
for (const auto& spk_and_groups_pair: spk_to_groups_map) {
const std::vector<OutputGroup>& groups_per_spk= spk_and_groups_pair.second;
// Go through the vector backwards. This allows for the first item we deal with being the partial group.
for (auto group_it = groups_per_spk.rbegin(); group_it != groups_per_spk.rend(); group_it++) {
const OutputGroup& group = *group_it;
// Don't include partial groups if there are full groups too and we don't want partial groups
if (group_it == groups_per_spk.rbegin() && groups_per_spk.size() > 1 && !filter.m_include_partial_groups) {
continue;
}
// Check the OutputGroup's eligibility. Only add the eligible ones.
if (positive_only && group.GetSelectionAmount() <= 0) continue;
if (group.m_outputs.size() > 0 && group.EligibleForSpending(filter)) groups_out.push_back(group);
}
}
return groups_out;
}
std::optional<SelectionResult> AttemptSelection(const CWallet& wallet, const CAmountMap& mapTargetValue, const CoinEligibilityFilter& eligibility_filter, std::vector<COutput> coins,
const CoinSelectionParams& coin_selection_params)
{
// Vector of results. We will choose the best one based on waste.
// std::vector<std::tuple<CAmount, std::set<CInputCoin>, CAmountMap>> results;
std::vector<SelectionResult> results;
// ELEMENTS: BnB only for policy asset?
if (mapTargetValue.size() == 1) {
// Note that unlike KnapsackSolver, we do not include the fee for creating a change output as BnB will not create a change output.
std::vector<OutputGroup> positive_groups = GroupOutputs(wallet, coins, coin_selection_params, eligibility_filter, true /* positive_only */);
// ELEMENTS:
CAsset asset = mapTargetValue.begin()->first;
CAmount nTargetValue = mapTargetValue.begin()->second;
// Get output groups that only contain this asset.
std::vector<OutputGroup> asset_groups;
for (OutputGroup g : positive_groups) {
bool add = true;
for (CInputCoin c : g.m_outputs) {
if (c.asset != asset) {
add = false;
break;
}
}
if (add) {
asset_groups.push_back(g);
}
}
// END ELEMENTS
if (auto bnb_result{SelectCoinsBnB(positive_groups, nTargetValue, coin_selection_params.m_cost_of_change)}) {
bnb_result->ComputeAndSetWaste(CAmount(0));
results.push_back(*bnb_result);
}
// We include the minimum final change for SRD as we do want to avoid making really small change.
// KnapsackSolver does not need this because it includes MIN_CHANGE internally.
const CAmount srd_target = nTargetValue + coin_selection_params.m_change_fee + MIN_FINAL_CHANGE;
if (auto srd_result{SelectCoinsSRD(positive_groups, srd_target)}) {
srd_result->ComputeAndSetWaste(coin_selection_params.m_cost_of_change);
results.push_back(*srd_result);
}
}
// 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.
std::vector<OutputGroup> all_groups = GroupOutputs(wallet, coins, coin_selection_params, eligibility_filter, false /* positive_only */);
// While mapTargetValue includes the transaction fees for non-input things, it does not include the fee for creating a change output.
// So we need to include that for KnapsackSolver as well, as we are expecting to create a change output.
CAmountMap mapTargetValue_copy = mapTargetValue;
if (!coin_selection_params.m_subtract_fee_outputs) {
mapTargetValue_copy[::policyAsset] += coin_selection_params.m_change_fee;
}
if (auto knapsack_result{KnapsackSolver(all_groups, mapTargetValue_copy)}) {
knapsack_result->ComputeAndSetWaste(coin_selection_params.m_cost_of_change);
results.push_back(*knapsack_result);
}
if (results.size() == 0) {
// No solution found
return std::nullopt;
}
// Choose the result with the least waste
// If the waste is the same, choose the one which spends more inputs.
auto& best_result = *std::min_element(results.begin(), results.end());
return best_result;
}
std::optional<SelectionResult> SelectCoins(const CWallet& wallet, const std::vector<COutput>& vAvailableCoins, const CAmountMap& mapTargetValue, const CCoinControl& coin_control, const CoinSelectionParams& coin_selection_params) EXCLUSIVE_LOCKS_REQUIRED(wallet.cs_wallet)
{
AssertLockHeld(wallet.cs_wallet);
std::vector<COutput> vCoins(vAvailableCoins);
CAmountMap value_to_select = mapTargetValue;
OutputGroup preset_inputs(coin_selection_params);
// coin control -> return all selected outputs (we want all selected to go into the transaction for sure)
if (coin_control.HasSelected() && !coin_control.fAllowOtherInputs)
{
for (const COutput& out : vCoins)
{
if (!out.fSpendable) continue;
CAmount amt = out.tx->GetOutputValueOut(wallet, out.i);
if (amt < 0) {
continue;
}
/* Set depth, from_me, ancestors, and descendants to 0 or false as these don't matter for preset inputs as no actual selection is being done.
* positive_only is set to false because we want to include all preset inputs, even if they are dust.
*/
preset_inputs.Insert(out.GetInputCoin(wallet), 0, false, 0, 0, false);
}
SelectionResult result(mapTargetValue);
result.AddInput(preset_inputs);
if (result.GetSelectedValue() < mapTargetValue) return std::nullopt;
return result;
}
// calculate value from preset inputs and store them
std::set<CInputCoin> setPresetCoins;
std::vector<COutPoint> vPresetInputs;
coin_control.ListSelected(vPresetInputs);
for (const COutPoint& outpoint : vPresetInputs) {
int input_bytes = -1;
CTxOut txout;
std::map<uint256, CWalletTx>::const_iterator it = wallet.mapWallet.find(outpoint.hash);
CInputCoin coin(outpoint, txout, 0); // dummy initialization
if (it != wallet.mapWallet.end()) {
const CWalletTx& wtx = it->second;
// Clearly invalid input, fail
if (wtx.tx->vout.size() <= outpoint.n) {
return std::nullopt;
}
// Just to calculate the marginal byte size
if (GetTxSpendSize(wallet, wtx, outpoint.n, outpoint.n) < 0) {
continue;
}
input_bytes = GetTxSpendSize(wallet, wtx, outpoint.n, false);
txout = wtx.tx->vout.at(outpoint.n);
coin = CInputCoin(wallet, &wtx, outpoint.n, input_bytes);
} else {
// The input is external. We did not find the tx in mapWallet.
if (!coin_control.GetExternalOutput(outpoint, txout)) {
return std::nullopt;
}
input_bytes = CalculateMaximumSignedInputSize(txout, &coin_control.m_external_provider, /* use_max_sig */ true);
// ELEMENTS: one more try to get a signed input size: for pegins,
// the outpoint is provided as external data but the information
// needed to spend is in the wallet (not the external provider,
// as the user is expecting the wallet to remember this information
// after they called getpeginaddress). So try estimating size with
// the wallet rather than the external provider.
if (input_bytes == -1) {
input_bytes = CalculateMaximumSignedInputSize(txout, &wallet, /* use_max_sig */ true);
}
if (!txout.nValue.IsExplicit() || !txout.nAsset.IsExplicit()) {
return std::nullopt; // We can't get its value, so abort
}
coin = CInputCoin(outpoint, txout, input_bytes);
}
// If available, override calculated size with coin control specified size
if (coin_control.HasInputWeight(outpoint)) {
input_bytes = GetVirtualTransactionSize(coin_control.GetInputWeight(outpoint), 0, 0);
coin = CInputCoin(outpoint, txout, input_bytes);
}
if (coin.m_input_bytes == -1) {
// error = _("Missing solving data for estimating transaction size"); // ELEMENTS
return std::nullopt; // Not solvable, can't estimate size for fee
}
coin.effective_value = coin.value - coin_selection_params.m_effective_feerate.GetFee(coin.m_input_bytes);
if (coin_selection_params.m_subtract_fee_outputs) {
value_to_select[coin.asset] -= coin.value;
} else {
value_to_select[coin.asset] -= coin.effective_value;
}
setPresetCoins.insert(coin);
/* Set depth, from_me, ancestors, and descendants to 0 or false as don't matter for preset inputs as no actual selection is being done.
* positive_only is set to false because we want to include all preset inputs, even if they are dust.
*/
preset_inputs.Insert(coin, 0, false, 0, 0, false);
}
// remove preset inputs from vCoins so that Coin Selection doesn't pick them.
for (std::vector<COutput>::iterator it = vCoins.begin(); it != vCoins.end() && coin_control.HasSelected();)
{
if (setPresetCoins.count(it->GetInputCoin(wallet)))
it = vCoins.erase(it);
else
++it;
}
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);
// ELEMENTS: filter coins for assets we are interested in; always keep policyAsset for fees
for (std::vector<COutput>::iterator it = vCoins.begin(); it != vCoins.end() && coin_control.HasSelected();) {
CAsset asset = it->GetInputCoin(wallet).asset;
if (asset != ::policyAsset && mapTargetValue.find(asset) == mapTargetValue.end()) {
it = vCoins.erase(it);
} else {
++it;
}
}
// form groups from remaining coins; note that preset coins will not
// automatically have their associated (same address) coins included
if (coin_control.m_avoid_partial_spends && vCoins.size() > OUTPUT_GROUP_MAX_ENTRIES) {
// 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
Shuffle(vCoins.begin(), vCoins.end(), FastRandomContext());
}
// We will have to do coin selection on the difference between the target and the provided values.
// If value_to_select <= 0 for all asset types, we are done; but unlike in Bitcoin, this may be
// true for some assets while being false for others. So clear all the "completed" assets out
// of value_to_select before calling AttemptSelection.
for (CAmountMap::const_iterator it = value_to_select.begin(); it != value_to_select.end();) {
if (it->second <= 0) {
it = value_to_select.erase(it);
} else {
++it;
}
}
// 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.
std::optional<SelectionResult> res = [&] {
// Pre-selected inputs already cover the target amount.
if (value_to_select <= CAmountMap{}) return std::make_optional(SelectionResult(mapTargetValue));
// 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.
if (auto r1{AttemptSelection(wallet, value_to_select, CoinEligibilityFilter(1, 6, 0), vCoins, coin_selection_params)}) return r1;
if (auto r2{AttemptSelection(wallet, value_to_select, CoinEligibilityFilter(1, 1, 0), vCoins, coin_selection_params)}) return r2;
// 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) {
if (auto r3{AttemptSelection(wallet, value_to_select, CoinEligibilityFilter(0, 1, 2), vCoins, coin_selection_params)}) return r3;
if (auto r4{AttemptSelection(wallet, value_to_select, CoinEligibilityFilter(0, 1, std::min((size_t)4, max_ancestors/3), std::min((size_t)4, max_descendants/3)),
vCoins, coin_selection_params)}) {
return r4;
}
if (auto r5{AttemptSelection(wallet, value_to_select, CoinEligibilityFilter(0, 1, max_ancestors/2, max_descendants/2),
vCoins, coin_selection_params)}) {
return r5;
}
// 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.
if (auto r6{AttemptSelection(wallet, value_to_select, CoinEligibilityFilter(0, 1, max_ancestors-1, max_descendants-1, true /* include_partial_groups */),
vCoins, coin_selection_params)}) {
return r6;
}
// Try with unsafe inputs if they are allowed. This may spend unconfirmed outputs
// received from other wallets.
if (coin_control.m_include_unsafe_inputs) {
if (auto r7{AttemptSelection(wallet, value_to_select,
CoinEligibilityFilter(0 /* conf_mine */, 0 /* conf_theirs */, max_ancestors-1, max_descendants-1, true /* include_partial_groups */),
vCoins, coin_selection_params)}) {
return r7;
}
}
// 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) {
if (auto r8{AttemptSelection(wallet, value_to_select,
CoinEligibilityFilter(0, 1, std::numeric_limits<uint64_t>::max(), std::numeric_limits<uint64_t>::max(), true /* include_partial_groups */),
vCoins, coin_selection_params)}) {
return r8;
}
}
}
// Coin Selection failed.
return std::optional<SelectionResult>();
}();
if (!res) return std::nullopt;
// add preset inputs to the total value selected
// Add preset inputs to result
res->AddInput(preset_inputs);
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;
}
/**
* Return 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 uint32_t GetLocktimeForNewTransaction(interfaces::Chain& chain, const uint256& block_hash, int block_height)
{
uint32_t locktime;
// 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)) {
locktime = 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 (GetRandInt(10) == 0)
locktime = std::max(0, (int)locktime - GetRandInt(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.
locktime = 0;
}
assert(locktime < LOCKTIME_THRESHOLD);
return locktime;
}
// Reset all non-global blinding details.
static void resetBlindDetails(BlindDetails* det, bool preserve_output_data = false) {
det->i_amount_blinds.clear();
det->i_asset_blinds.clear();
det->i_assets.clear();
det->i_amounts.clear();
det->o_amounts.clear();
if (!preserve_output_data) {
det->o_pubkeys.clear();
}
det->o_amount_blinds.clear();
det->o_assets.clear();
det->o_asset_blinds.clear();
if (!preserve_output_data) {
det->num_to_blind = 0;
det->change_to_blind = 0;
det->only_recipient_blind_index = -1;
det->only_change_pos = -1;
}
}
static bool fillBlindDetails(BlindDetails* det, CWallet* wallet, CMutableTransaction& txNew, std::vector<CInputCoin>& selected_coins, bilingual_str& error) {
int num_inputs_blinded = 0;
// Fill in input blinding details
for (const CInputCoin& coin : selected_coins) {
det->i_amount_blinds.push_back(coin.bf_value);
det->i_asset_blinds.push_back(coin.bf_asset);
det->i_assets.push_back(coin.asset);
det->i_amounts.push_back(coin.value);
if (coin.txout.nValue.IsCommitment() || coin.txout.nAsset.IsCommitment()) {
num_inputs_blinded++;
}
}
// Fill in output blinding details
for (size_t nOut = 0; nOut < txNew.vout.size(); nOut++) {
//TODO(CA) consider removing all blind setting before BlindTransaction as they get cleared anyway
det->o_amount_blinds.push_back(uint256());
det->o_asset_blinds.push_back(uint256());
det->o_assets.push_back(txNew.vout[nOut].nAsset.GetAsset());
det->o_amounts.push_back(txNew.vout[nOut].nValue.GetAmount());
}
// There are a few edge-cases of blinding we need to take care of
//
// First, if there are blinded inputs but not outputs to blind
// We need this to go through, even though no privacy is gained.
if (num_inputs_blinded > 0 && det->num_to_blind == 0) {
// We need to make sure to dupe an asset that is in input set
//TODO Have blinding do some extremely minimal rangeproof
CTxOut newTxOut(det->o_assets.back(), 0, CScript() << OP_RETURN);
CPubKey blind_pub = wallet->GetBlindingPubKey(newTxOut.scriptPubKey); // irrelevant, just needs to be non-null
newTxOut.nNonce.vchCommitment = std::vector<unsigned char>(blind_pub.begin(), blind_pub.end());
txNew.vout.push_back(newTxOut);
det->o_pubkeys.push_back(wallet->GetBlindingPubKey(newTxOut.scriptPubKey));
det->o_amount_blinds.push_back(uint256());
det->o_asset_blinds.push_back(uint256());
det->o_amounts.push_back(0);
det->o_assets.push_back(det->o_assets.back());
det->num_to_blind++;
wallet->WalletLogPrintf("Adding OP_RETURN output to complete blinding since there are %d blinded inputs and no blinded outputs\n", num_inputs_blinded);
// No blinded inputs, but 1 blinded output
} else if (num_inputs_blinded == 0 && det->num_to_blind == 1) {
if (det->change_to_blind == 1) {
// Only 1 blinded change, unblind the change
//TODO Split up change instead if possible
if (det->ignore_blind_failure) {
det->num_to_blind--;
det->change_to_blind--;
txNew.vout[det->only_change_pos].nNonce.SetNull();
det->o_pubkeys[det->only_change_pos] = CPubKey();
det->o_amount_blinds[det->only_change_pos] = uint256();
det->o_asset_blinds[det->only_change_pos] = uint256();
wallet->WalletLogPrintf("Unblinding change at index %d due to lack of inputs and other outputs being blinded.\n", det->only_change_pos);
} else {
error = _("Change output could not be blinded as there are no blinded inputs and no other blinded outputs.");
return false;
}
} else {
// 1 blinded destination
// TODO Attempt to get a blinded input, OR add unblinded coin to make blinded change
assert(det->only_recipient_blind_index != -1);
if (det->ignore_blind_failure) {
det->num_to_blind--;
txNew.vout[det->only_recipient_blind_index].nNonce.SetNull();
det->o_pubkeys[det->only_recipient_blind_index] = CPubKey();
det->o_amount_blinds[det->only_recipient_blind_index] = uint256();
det->o_asset_blinds[det->only_recipient_blind_index] = uint256();
wallet->WalletLogPrintf("Unblinding single blinded output at index %d due to lack of inputs and other outputs being blinded.\n", det->only_recipient_blind_index);
} else {
error = _("Transaction output could not be blinded as there are no blinded inputs and no other blinded outputs.");
return false;
}
}
}
// All other combinations should work.
return true;
}
static bool CreateTransactionInternal(
CWallet& wallet,
const std::vector<CRecipient>& vecSend,
CTransactionRef& tx,
CAmount& nFeeRet,
int& nChangePosInOut,
bilingual_str& error,
const CCoinControl& coin_control,
FeeCalculation& fee_calc_out,
bool sign,
BlindDetails* blind_details,
const IssuanceDetails* issuance_details) EXCLUSIVE_LOCKS_REQUIRED(wallet.cs_wallet)
{
if (blind_details || issuance_details) {
assert(g_con_elementsmode);
}
if (blind_details) {
// Clear out previous blinding/data info as needed
resetBlindDetails(blind_details);
}
AssertLockHeld(wallet.cs_wallet);
CMutableTransaction txNew; // The resulting transaction that we make
txNew.nLockTime = GetLocktimeForNewTransaction(wallet.chain(), wallet.GetLastBlockHash(), wallet.GetLastBlockHeight());
CoinSelectionParams coin_selection_params; // Parameters for coin selection, init with dummy
coin_selection_params.m_avoid_partial_spends = coin_control.m_avoid_partial_spends;
CScript dummy_script = CScript() << 0x00;
CAmountMap map_recipients_sum;
// Always assume that we are at least sending policyAsset.
map_recipients_sum[::policyAsset] = 0;
std::vector<std::unique_ptr<ReserveDestination>> reservedest;
// Set the long term feerate estimate to the wallet's consolidate feerate
coin_selection_params.m_long_term_feerate = wallet.m_consolidate_feerate;
const OutputType change_type = wallet.TransactionChangeType(coin_control.m_change_type ? *coin_control.m_change_type : wallet.m_default_change_type, vecSend);
reservedest.emplace_back(new ReserveDestination(&wallet, change_type)); // policy asset
std::set<CAsset> assets_seen;
unsigned int outputs_to_subtract_fee_from = 0; // The number of outputs which we are subtracting the fee from
for (const auto& recipient : vecSend)
{
// Pad change keys to cover total possible number of assets
// One already exists(for policyAsset), so one for each destination
if (assets_seen.insert(recipient.asset).second) {
reservedest.emplace_back(new ReserveDestination(&wallet, change_type));
}
// Skip over issuance outputs, no need to select those coins
if (recipient.asset == CAsset(uint256S("1")) || recipient.asset == CAsset(uint256S("2"))) {
continue;
}
map_recipients_sum[recipient.asset] += 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
// ELEMENTS: A map that keeps track of the change script for each asset and also
// the index of the reservedest used for that script (-1 if none).
std::map<CAsset, std::pair<int, CScript>> mapScriptChange;
// For manually set change, we need to use the blinding pubkey associated
// with the manually-set address rather than generating one from the wallet
std::map<CAsset, std::optional<CPubKey>> mapBlindingKeyChange;
// coin control: send change to custom address
if (coin_control.destChange.size() > 0) {
for (const auto& dest : coin_control.destChange) {
// No need to test we cover all assets. We produce error for that later.
mapScriptChange[dest.first] = std::pair<int, CScript>(-1, GetScriptForDestination(dest.second));
if (IsBlindDestination(dest.second)) {
mapBlindingKeyChange[dest.first] = GetDestinationBlindingKey(dest.second);
} else {
mapBlindingKeyChange[dest.first] = std::nullopt;
}
}