-
Notifications
You must be signed in to change notification settings - Fork 2.1k
/
client_db.go
1199 lines (1000 loc) · 33.8 KB
/
client_db.go
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
package wtdb
import (
"bytes"
"errors"
"fmt"
"math"
"net"
"time"
"github.com/btcsuite/btcd/btcec"
"github.com/lightningnetwork/lnd/channeldb/kvdb"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/watchtower/blob"
)
const (
// clientDBName is the filename of client database.
clientDBName = "wtclient.db"
)
var (
// cSessionKeyIndexBkt is a top-level bucket storing:
// tower-id -> reserved-session-key-index (uint32).
cSessionKeyIndexBkt = []byte("client-session-key-index-bucket")
// cChanSummaryBkt is a top-level bucket storing:
// channel-id -> encoded ClientChanSummary.
cChanSummaryBkt = []byte("client-channel-summary-bucket")
// cSessionBkt is a top-level bucket storing:
// session-id => cSessionBody -> encoded ClientSessionBody
// => cSessionCommits => seqnum -> encoded CommittedUpdate
// => cSessionAcks => seqnum -> encoded BackupID
cSessionBkt = []byte("client-session-bucket")
// cSessionBody is a sub-bucket of cSessionBkt storing only the body of
// the ClientSession.
cSessionBody = []byte("client-session-body")
// cSessionBody is a sub-bucket of cSessionBkt storing:
// seqnum -> encoded CommittedUpdate.
cSessionCommits = []byte("client-session-commits")
// cSessionAcks is a sub-bucket of cSessionBkt storing:
// seqnum -> encoded BackupID.
cSessionAcks = []byte("client-session-acks")
// cTowerBkt is a top-level bucket storing:
// tower-id -> encoded Tower.
cTowerBkt = []byte("client-tower-bucket")
// cTowerIndexBkt is a top-level bucket storing:
// tower-pubkey -> tower-id.
cTowerIndexBkt = []byte("client-tower-index-bucket")
// ErrTowerNotFound signals that the target tower was not found in the
// database.
ErrTowerNotFound = errors.New("tower not found")
// ErrTowerUnackedUpdates is an error returned when we attempt to mark a
// tower's sessions as inactive, but one of its sessions has unacked
// updates.
ErrTowerUnackedUpdates = errors.New("tower has unacked updates")
// ErrCorruptClientSession signals that the client session's on-disk
// structure deviates from what is expected.
ErrCorruptClientSession = errors.New("client session corrupted")
// ErrClientSessionAlreadyExists signals an attempt to reinsert a client
// session that has already been created.
ErrClientSessionAlreadyExists = errors.New(
"client session already exists",
)
// ErrChannelAlreadyRegistered signals a duplicate attempt to register a
// channel with the client database.
ErrChannelAlreadyRegistered = errors.New("channel already registered")
// ErrChannelNotRegistered signals a channel has not yet been registered
// in the client database.
ErrChannelNotRegistered = errors.New("channel not registered")
// ErrClientSessionNotFound signals that the requested client session
// was not found in the database.
ErrClientSessionNotFound = errors.New("client session not found")
// ErrUpdateAlreadyCommitted signals that the chosen sequence number has
// already been committed to an update with a different breach hint.
ErrUpdateAlreadyCommitted = errors.New("update already committed")
// ErrCommitUnorderedUpdate signals the client tried to commit a
// sequence number other than the next unallocated sequence number.
ErrCommitUnorderedUpdate = errors.New("update seqnum not monotonic")
// ErrCommittedUpdateNotFound signals that the tower tried to ACK a
// sequence number that has not yet been allocated by the client.
ErrCommittedUpdateNotFound = errors.New("committed update not found")
// ErrUnallocatedLastApplied signals that the tower tried to provide a
// LastApplied value greater than any allocated sequence number.
ErrUnallocatedLastApplied = errors.New("tower echoed last appiled " +
"greater than allocated seqnum")
// ErrNoReservedKeyIndex signals that a client session could not be
// created because no session key index was reserved.
ErrNoReservedKeyIndex = errors.New("key index not reserved")
// ErrIncorrectKeyIndex signals that the client session could not be
// created because session key index differs from the reserved key
// index.
ErrIncorrectKeyIndex = errors.New("incorrect key index")
// ErrLastTowerAddr is an error returned when the last address of a
// watchtower is attempted to be removed.
ErrLastTowerAddr = errors.New("cannot remove last tower address")
)
// ClientDB is single database providing a persistent storage engine for the
// wtclient.
type ClientDB struct {
db kvdb.Backend
dbPath string
}
// OpenClientDB opens the client database given the path to the database's
// directory. If no such database exists, this method will initialize a fresh
// one using the latest version number and bucket structure. If a database
// exists but has a lower version number than the current version, any necessary
// migrations will be applied before returning. Any attempt to open a database
// with a version number higher that the latest version will fail to prevent
// accidental reversion.
func OpenClientDB(dbPath string, dbTimeout time.Duration) (*ClientDB, error) {
bdb, firstInit, err := createDBIfNotExist(
dbPath, clientDBName, dbTimeout,
)
if err != nil {
return nil, err
}
clientDB := &ClientDB{
db: bdb,
dbPath: dbPath,
}
err = initOrSyncVersions(clientDB, firstInit, clientDBVersions)
if err != nil {
bdb.Close()
return nil, err
}
// Now that the database version fully consistent with our latest known
// version, ensure that all top-level buckets known to this version are
// initialized. This allows us to assume their presence throughout all
// operations. If an known top-level bucket is expected to exist but is
// missing, this will trigger a ErrUninitializedDB error.
err = kvdb.Update(clientDB.db, initClientDBBuckets, func() {})
if err != nil {
bdb.Close()
return nil, err
}
return clientDB, nil
}
// initClientDBBuckets creates all top-level buckets required to handle database
// operations required by the latest version.
func initClientDBBuckets(tx kvdb.RwTx) error {
buckets := [][]byte{
cSessionKeyIndexBkt,
cChanSummaryBkt,
cSessionBkt,
cTowerBkt,
cTowerIndexBkt,
}
for _, bucket := range buckets {
_, err := tx.CreateTopLevelBucket(bucket)
if err != nil {
return err
}
}
return nil
}
// bdb returns the backing bbolt.DB instance.
//
// NOTE: Part of the versionedDB interface.
func (c *ClientDB) bdb() kvdb.Backend {
return c.db
}
// Version returns the database's current version number.
//
// NOTE: Part of the versionedDB interface.
func (c *ClientDB) Version() (uint32, error) {
var version uint32
err := kvdb.View(c.db, func(tx kvdb.RTx) error {
var err error
version, err = getDBVersion(tx)
return err
}, func() {
version = 0
})
if err != nil {
return 0, err
}
return version, nil
}
// Close closes the underlying database.
func (c *ClientDB) Close() error {
return c.db.Close()
}
// CreateTower initialize an address record used to communicate with a
// watchtower. Each Tower is assigned a unique ID, that is used to amortize
// storage costs of the public key when used by multiple sessions. If the tower
// already exists, the address is appended to the list of all addresses used to
// that tower previously and its corresponding sessions are marked as active.
func (c *ClientDB) CreateTower(lnAddr *lnwire.NetAddress) (*Tower, error) {
var towerPubKey [33]byte
copy(towerPubKey[:], lnAddr.IdentityKey.SerializeCompressed())
var tower *Tower
err := kvdb.Update(c.db, func(tx kvdb.RwTx) error {
towerIndex := tx.ReadWriteBucket(cTowerIndexBkt)
if towerIndex == nil {
return ErrUninitializedDB
}
towers := tx.ReadWriteBucket(cTowerBkt)
if towers == nil {
return ErrUninitializedDB
}
// Check if the tower index already knows of this pubkey.
towerIDBytes := towerIndex.Get(towerPubKey[:])
if len(towerIDBytes) == 8 {
// The tower already exists, deserialize the existing
// record.
var err error
tower, err = getTower(towers, towerIDBytes)
if err != nil {
return err
}
// Add the new address to the existing tower. If the
// address is a duplicate, this will result in no
// change.
tower.AddAddress(lnAddr.Address)
// If there are any client sessions that correspond to
// this tower, we'll mark them as active to ensure we
// load them upon restarts.
//
// TODO(wilmer): with an index of tower -> sessions we
// can avoid the linear lookup.
sessions := tx.ReadWriteBucket(cSessionBkt)
if sessions == nil {
return ErrUninitializedDB
}
towerID := TowerIDFromBytes(towerIDBytes)
towerSessions, err := listClientSessions(
sessions, &towerID,
)
if err != nil {
return err
}
for _, session := range towerSessions {
err := markSessionStatus(
sessions, session, CSessionActive,
)
if err != nil {
return err
}
}
} else {
// No such tower exists, create a new tower id for our
// new tower. The error is unhandled since NextSequence
// never fails in an Update.
towerID, _ := towerIndex.NextSequence()
tower = &Tower{
ID: TowerID(towerID),
IdentityKey: lnAddr.IdentityKey,
Addresses: []net.Addr{lnAddr.Address},
}
towerIDBytes = tower.ID.Bytes()
// Since this tower is new, record the mapping from
// tower pubkey to tower id in the tower index.
err := towerIndex.Put(towerPubKey[:], towerIDBytes)
if err != nil {
return err
}
}
// Store the new or updated tower under its tower id.
return putTower(towers, tower)
}, func() {
tower = nil
})
if err != nil {
return nil, err
}
return tower, nil
}
// RemoveTower modifies a tower's record within the database. If an address is
// provided, then _only_ the address record should be removed from the tower's
// persisted state. Otherwise, we'll attempt to mark the tower as inactive by
// marking all of its sessions inactive. If any of its sessions has unacked
// updates, then ErrTowerUnackedUpdates is returned. If the tower doesn't have
// any sessions at all, it'll be completely removed from the database.
//
// NOTE: An error is not returned if the tower doesn't exist.
func (c *ClientDB) RemoveTower(pubKey *btcec.PublicKey, addr net.Addr) error {
return kvdb.Update(c.db, func(tx kvdb.RwTx) error {
towers := tx.ReadWriteBucket(cTowerBkt)
if towers == nil {
return ErrUninitializedDB
}
towerIndex := tx.ReadWriteBucket(cTowerIndexBkt)
if towerIndex == nil {
return ErrUninitializedDB
}
// Don't return an error if the watchtower doesn't exist to act
// as a NOP.
pubKeyBytes := pubKey.SerializeCompressed()
towerIDBytes := towerIndex.Get(pubKeyBytes)
if towerIDBytes == nil {
return nil
}
// If an address is provided, then we should _only_ remove the
// address record from the database.
if addr != nil {
tower, err := getTower(towers, towerIDBytes)
if err != nil {
return err
}
// Towers should always have at least one address saved.
tower.RemoveAddress(addr)
if len(tower.Addresses) == 0 {
return ErrLastTowerAddr
}
return putTower(towers, tower)
}
// Otherwise, we should attempt to mark the tower's sessions as
// inactive.
//
// TODO(wilmer): with an index of tower -> sessions we can avoid
// the linear lookup.
sessions := tx.ReadWriteBucket(cSessionBkt)
if sessions == nil {
return ErrUninitializedDB
}
towerID := TowerIDFromBytes(towerIDBytes)
towerSessions, err := listClientSessions(sessions, &towerID)
if err != nil {
return err
}
// If it doesn't have any, we can completely remove it from the
// database.
if len(towerSessions) == 0 {
if err := towerIndex.Delete(pubKeyBytes); err != nil {
return err
}
return towers.Delete(towerIDBytes)
}
// We'll mark its sessions as inactive as long as they don't
// have any pending updates to ensure we don't load them upon
// restarts.
for _, session := range towerSessions {
if len(session.CommittedUpdates) > 0 {
return ErrTowerUnackedUpdates
}
err := markSessionStatus(
sessions, session, CSessionInactive,
)
if err != nil {
return err
}
}
return nil
}, func() {})
}
// LoadTowerByID retrieves a tower by its tower ID.
func (c *ClientDB) LoadTowerByID(towerID TowerID) (*Tower, error) {
var tower *Tower
err := kvdb.View(c.db, func(tx kvdb.RTx) error {
towers := tx.ReadBucket(cTowerBkt)
if towers == nil {
return ErrUninitializedDB
}
var err error
tower, err = getTower(towers, towerID.Bytes())
return err
}, func() {
tower = nil
})
if err != nil {
return nil, err
}
return tower, nil
}
// LoadTower retrieves a tower by its public key.
func (c *ClientDB) LoadTower(pubKey *btcec.PublicKey) (*Tower, error) {
var tower *Tower
err := kvdb.View(c.db, func(tx kvdb.RTx) error {
towers := tx.ReadBucket(cTowerBkt)
if towers == nil {
return ErrUninitializedDB
}
towerIndex := tx.ReadBucket(cTowerIndexBkt)
if towerIndex == nil {
return ErrUninitializedDB
}
towerIDBytes := towerIndex.Get(pubKey.SerializeCompressed())
if towerIDBytes == nil {
return ErrTowerNotFound
}
var err error
tower, err = getTower(towers, towerIDBytes)
return err
}, func() {
tower = nil
})
if err != nil {
return nil, err
}
return tower, nil
}
// ListTowers retrieves the list of towers available within the database.
func (c *ClientDB) ListTowers() ([]*Tower, error) {
var towers []*Tower
err := kvdb.View(c.db, func(tx kvdb.RTx) error {
towerBucket := tx.ReadBucket(cTowerBkt)
if towerBucket == nil {
return ErrUninitializedDB
}
return towerBucket.ForEach(func(towerIDBytes, _ []byte) error {
tower, err := getTower(towerBucket, towerIDBytes)
if err != nil {
return err
}
towers = append(towers, tower)
return nil
})
}, func() {
towers = nil
})
if err != nil {
return nil, err
}
return towers, nil
}
// NextSessionKeyIndex reserves a new session key derivation index for a
// particular tower id. The index is reserved for that tower until
// CreateClientSession is invoked for that tower and index, at which point a new
// index for that tower can be reserved. Multiple calls to this method before
// CreateClientSession is invoked should return the same index.
func (c *ClientDB) NextSessionKeyIndex(towerID TowerID,
blobType blob.Type) (uint32, error) {
var index uint32
err := kvdb.Update(c.db, func(tx kvdb.RwTx) error {
keyIndex := tx.ReadWriteBucket(cSessionKeyIndexBkt)
if keyIndex == nil {
return ErrUninitializedDB
}
// Check the session key index to see if a key has already been
// reserved for this tower. If so, we'll deserialize and return
// the index directly.
var err error
index, err = getSessionKeyIndex(keyIndex, towerID, blobType)
if err == nil {
return nil
}
// Otherwise, generate a new session key index since the node
// doesn't already have reserved index. The error is ignored
// since NextSequence can't fail inside Update.
index64, _ := keyIndex.NextSequence()
// As a sanity check, assert that the index is still in the
// valid range of unhardened pubkeys. In the future, we should
// move to only using hardened keys, and this will prevent any
// overlap from occurring until then. This also prevents us from
// overflowing uint32s.
if index64 > math.MaxInt32 {
return fmt.Errorf("exhausted session key indexes")
}
// Create the key that will used to be store the reserved index.
keyBytes := createSessionKeyIndexKey(towerID, blobType)
index = uint32(index64)
var indexBuf [4]byte
byteOrder.PutUint32(indexBuf[:], index)
// Record the reserved session key index under this tower's id.
return keyIndex.Put(keyBytes, indexBuf[:])
}, func() {
index = 0
})
if err != nil {
return 0, err
}
return index, nil
}
// CreateClientSession records a newly negotiated client session in the set of
// active sessions. The session can be identified by its SessionID.
func (c *ClientDB) CreateClientSession(session *ClientSession) error {
return kvdb.Update(c.db, func(tx kvdb.RwTx) error {
keyIndexes := tx.ReadWriteBucket(cSessionKeyIndexBkt)
if keyIndexes == nil {
return ErrUninitializedDB
}
sessions := tx.ReadWriteBucket(cSessionBkt)
if sessions == nil {
return ErrUninitializedDB
}
// Check that client session with this session id doesn't
// already exist.
existingSessionBytes := sessions.NestedReadWriteBucket(session.ID[:])
if existingSessionBytes != nil {
return ErrClientSessionAlreadyExists
}
towerID := session.TowerID
blobType := session.Policy.BlobType
// Check that this tower has a reserved key index.
index, err := getSessionKeyIndex(keyIndexes, towerID, blobType)
if err != nil {
return err
}
// Assert that the key index of the inserted session matches the
// reserved session key index.
if index != session.KeyIndex {
return ErrIncorrectKeyIndex
}
// Remove the key index reservation. For altruist commit
// sessions, we'll also purge under the old legacy key format.
key := createSessionKeyIndexKey(towerID, blobType)
err = keyIndexes.Delete(key)
if err != nil {
return err
}
if blobType == blob.TypeAltruistCommit {
err = keyIndexes.Delete(towerID.Bytes())
if err != nil {
return err
}
}
// Finally, write the client session's body in the sessions
// bucket.
return putClientSessionBody(sessions, session)
}, func() {})
}
// createSessionKeyIndexKey returns the indentifier used in the
// session-key-index index, created as tower-id||blob-type.
//
// NOTE: The original serialization only used tower-id, which prevents
// concurrent client types from reserving sessions with the same tower.
func createSessionKeyIndexKey(towerID TowerID, blobType blob.Type) []byte {
towerIDBytes := towerID.Bytes()
// Session key indexes are stored under as tower-id||blob-type.
var keyBytes [6]byte
copy(keyBytes[:4], towerIDBytes)
byteOrder.PutUint16(keyBytes[4:], uint16(blobType))
return keyBytes[:]
}
// getSessionKeyIndex is a helper method
func getSessionKeyIndex(keyIndexes kvdb.RwBucket, towerID TowerID,
blobType blob.Type) (uint32, error) {
// Session key indexes are store under as tower-id||blob-type. The
// original serialization only used tower-id, which prevents concurrent
// client types from reserving sessions with the same tower.
keyBytes := createSessionKeyIndexKey(towerID, blobType)
// Retrieve the index using the key bytes. If the key wasn't found, we
// will fall back to the legacy format that only uses the tower id, but
// _only_ if the blob type is for altruist commit sessions since that
// was the only operational session type prior to changing the key
// format.
keyIndexBytes := keyIndexes.Get(keyBytes)
if keyIndexBytes == nil && blobType == blob.TypeAltruistCommit {
keyIndexBytes = keyIndexes.Get(towerID.Bytes())
}
// All session key indexes should be serialized uint32's. If no key
// index was found, the length of keyIndexBytes will be 0.
if len(keyIndexBytes) != 4 {
return 0, ErrNoReservedKeyIndex
}
return byteOrder.Uint32(keyIndexBytes), nil
}
// ListClientSessions returns the set of all client sessions known to the db. An
// optional tower ID can be used to filter out any client sessions in the
// response that do not correspond to this tower.
func (c *ClientDB) ListClientSessions(id *TowerID) (map[SessionID]*ClientSession, error) {
var clientSessions map[SessionID]*ClientSession
err := kvdb.View(c.db, func(tx kvdb.RTx) error {
sessions := tx.ReadBucket(cSessionBkt)
if sessions == nil {
return ErrUninitializedDB
}
var err error
clientSessions, err = listClientSessions(sessions, id)
return err
}, func() {
clientSessions = nil
})
if err != nil {
return nil, err
}
return clientSessions, nil
}
// listClientSessions returns the set of all client sessions known to the db. An
// optional tower ID can be used to filter out any client sessions in the
// response that do not correspond to this tower.
func listClientSessions(sessions kvdb.RBucket,
id *TowerID) (map[SessionID]*ClientSession, error) {
clientSessions := make(map[SessionID]*ClientSession)
err := sessions.ForEach(func(k, _ []byte) error {
// We'll load the full client session since the client will need
// the CommittedUpdates and AckedUpdates on startup to resume
// committed updates and compute the highest known commit height
// for each channel.
session, err := getClientSession(sessions, k)
if err != nil {
return err
}
// Filter out any sessions that don't correspond to the given
// tower if one was set.
if id != nil && session.TowerID != *id {
return nil
}
clientSessions[session.ID] = session
return nil
})
if err != nil {
return nil, err
}
return clientSessions, nil
}
// FetchChanSummaries loads a mapping from all registered channels to their
// channel summaries.
func (c *ClientDB) FetchChanSummaries() (ChannelSummaries, error) {
var summaries map[lnwire.ChannelID]ClientChanSummary
err := kvdb.View(c.db, func(tx kvdb.RTx) error {
chanSummaries := tx.ReadBucket(cChanSummaryBkt)
if chanSummaries == nil {
return ErrUninitializedDB
}
return chanSummaries.ForEach(func(k, v []byte) error {
var chanID lnwire.ChannelID
copy(chanID[:], k)
var summary ClientChanSummary
err := summary.Decode(bytes.NewReader(v))
if err != nil {
return err
}
summaries[chanID] = summary
return nil
})
}, func() {
summaries = make(map[lnwire.ChannelID]ClientChanSummary)
})
if err != nil {
return nil, err
}
return summaries, nil
}
// RegisterChannel registers a channel for use within the client database. For
// now, all that is stored in the channel summary is the sweep pkscript that
// we'd like any tower sweeps to pay into. In the future, this will be extended
// to contain more info to allow the client efficiently request historical
// states to be backed up under the client's active policy.
func (c *ClientDB) RegisterChannel(chanID lnwire.ChannelID,
sweepPkScript []byte) error {
return kvdb.Update(c.db, func(tx kvdb.RwTx) error {
chanSummaries := tx.ReadWriteBucket(cChanSummaryBkt)
if chanSummaries == nil {
return ErrUninitializedDB
}
_, err := getChanSummary(chanSummaries, chanID)
switch {
// Summary already exists.
case err == nil:
return ErrChannelAlreadyRegistered
// Channel is not registered, proceed with registration.
case err == ErrChannelNotRegistered:
// Unexpected error.
default:
return err
}
summary := ClientChanSummary{
SweepPkScript: sweepPkScript,
}
return putChanSummary(chanSummaries, chanID, &summary)
}, func() {})
}
// MarkBackupIneligible records that the state identified by the (channel id,
// commit height) tuple was ineligible for being backed up under the current
// policy. This state can be retried later under a different policy.
func (c *ClientDB) MarkBackupIneligible(chanID lnwire.ChannelID,
commitHeight uint64) error {
return nil
}
// CommitUpdate persists the CommittedUpdate provided in the slot for (session,
// seqNum). This allows the client to retransmit this update on startup.
func (c *ClientDB) CommitUpdate(id *SessionID,
update *CommittedUpdate) (uint16, error) {
var lastApplied uint16
err := kvdb.Update(c.db, func(tx kvdb.RwTx) error {
sessions := tx.ReadWriteBucket(cSessionBkt)
if sessions == nil {
return ErrUninitializedDB
}
// We'll only load the ClientSession body for performance, since
// we primarily need to inspect its SeqNum and TowerLastApplied
// fields. The CommittedUpdates will be modified on disk
// directly.
session, err := getClientSessionBody(sessions, id[:])
if err != nil {
return err
}
// Can't fail if the above didn't fail.
sessionBkt := sessions.NestedReadWriteBucket(id[:])
// Ensure the session commits sub-bucket is initialized.
sessionCommits, err := sessionBkt.CreateBucketIfNotExists(
cSessionCommits,
)
if err != nil {
return err
}
var seqNumBuf [2]byte
byteOrder.PutUint16(seqNumBuf[:], update.SeqNum)
// Check to see if a committed update already exists for this
// sequence number.
committedUpdateBytes := sessionCommits.Get(seqNumBuf[:])
if committedUpdateBytes != nil {
var dbUpdate CommittedUpdate
err := dbUpdate.Decode(
bytes.NewReader(committedUpdateBytes),
)
if err != nil {
return err
}
// If an existing committed update has a different hint,
// we'll reject this newer update.
if dbUpdate.Hint != update.Hint {
return ErrUpdateAlreadyCommitted
}
// Otherwise, capture the last applied value and
// succeed.
lastApplied = session.TowerLastApplied
return nil
}
// There's no committed update for this sequence number, ensure
// that we are committing the next unallocated one.
if update.SeqNum != session.SeqNum+1 {
return ErrCommitUnorderedUpdate
}
// Increment the session's sequence number and store the updated
// client session.
//
// TODO(conner): split out seqnum and last applied own bucket to
// eliminate serialization of full struct during CommitUpdate?
// Can also read/write directly to byes [:2] without migration.
session.SeqNum++
err = putClientSessionBody(sessions, session)
if err != nil {
return err
}
// Encode and store the committed update in the sessionCommits
// sub-bucket under the requested sequence number.
var b bytes.Buffer
err = update.Encode(&b)
if err != nil {
return err
}
err = sessionCommits.Put(seqNumBuf[:], b.Bytes())
if err != nil {
return err
}
// Finally, capture the session's last applied value so it can
// be sent in the next state update to the tower.
lastApplied = session.TowerLastApplied
return nil
}, func() {
lastApplied = 0
})
if err != nil {
return 0, err
}
return lastApplied, nil
}
// AckUpdate persists an acknowledgment for a given (session, seqnum) pair. This
// removes the update from the set of committed updates, and validates the
// lastApplied value returned from the tower.
func (c *ClientDB) AckUpdate(id *SessionID, seqNum uint16,
lastApplied uint16) error {
return kvdb.Update(c.db, func(tx kvdb.RwTx) error {
sessions := tx.ReadWriteBucket(cSessionBkt)
if sessions == nil {
return ErrUninitializedDB
}
// We'll only load the ClientSession body for performance, since
// we primarily need to inspect its SeqNum and TowerLastApplied
// fields. The CommittedUpdates and AckedUpdates will be
// modified on disk directly.
session, err := getClientSessionBody(sessions, id[:])
if err != nil {
return err
}
// If the tower has acked a sequence number beyond our highest
// sequence number, fail.
if lastApplied > session.SeqNum {
return ErrUnallocatedLastApplied
}
// If the tower acked with a lower sequence number than it gave
// us prior, fail.
if lastApplied < session.TowerLastApplied {
return ErrLastAppliedReversion
}
// TODO(conner): split out seqnum and last applied own bucket to
// eliminate serialization of full struct during AckUpdate? Can
// also read/write directly to byes [2:4] without migration.
session.TowerLastApplied = lastApplied
// Write the client session with the updated last applied value.
err = putClientSessionBody(sessions, session)
if err != nil {
return err
}
// Can't fail because of getClientSession succeeded.
sessionBkt := sessions.NestedReadWriteBucket(id[:])
// If the commits sub-bucket doesn't exist, there can't possibly
// be a corresponding committed update to remove.
sessionCommits := sessionBkt.NestedReadWriteBucket(cSessionCommits)
if sessionCommits == nil {
return ErrCommittedUpdateNotFound
}
var seqNumBuf [2]byte
byteOrder.PutUint16(seqNumBuf[:], seqNum)
// Assert that a committed update exists for this sequence
// number.
committedUpdateBytes := sessionCommits.Get(seqNumBuf[:])
if committedUpdateBytes == nil {
return ErrCommittedUpdateNotFound
}
var committedUpdate CommittedUpdate
err = committedUpdate.Decode(
bytes.NewReader(committedUpdateBytes),
)
if err != nil {
return err
}
// Remove the corresponding committed update.
err = sessionCommits.Delete(seqNumBuf[:])
if err != nil {
return err
}
// Ensure that the session acks sub-bucket is initialized so we
// can insert an entry.
sessionAcks, err := sessionBkt.CreateBucketIfNotExists(
cSessionAcks,
)
if err != nil {
return err
}
// The session acks only need to track the backup id of the
// update, so we can discard the blob and hint.
var b bytes.Buffer
err = committedUpdate.BackupID.Encode(&b)
if err != nil {
return err
}
// Finally, insert the ack into the sessionAcks sub-bucket.
return sessionAcks.Put(seqNumBuf[:], b.Bytes())
}, func() {})
}
// getClientSessionBody loads the body of a ClientSession from the sessions
// bucket corresponding to the serialized session id. This does not deserialize
// the CommittedUpdates or AckUpdates associated with the session. If the caller
// requires this info, use getClientSession.
func getClientSessionBody(sessions kvdb.RBucket,
idBytes []byte) (*ClientSession, error) {
sessionBkt := sessions.NestedReadBucket(idBytes)
if sessionBkt == nil {
return nil, ErrClientSessionNotFound
}
// Should never have a sessionBkt without also having its body.
sessionBody := sessionBkt.Get(cSessionBody)
if sessionBody == nil {
return nil, ErrCorruptClientSession
}
var session ClientSession