aboutsummaryrefslogtreecommitdiffstats
path: root/dex/peer.go
blob: 195be920e03425113b892d19f8b204d801f6956c (plain) (blame)
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
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package dex

import (
    "errors"
    "fmt"
    "math/big"
    "sync"
    "time"

    mapset "github.com/deckarep/golang-set"
    coreTypes "github.com/dexon-foundation/dexon-consensus-core/core/types"
    dkgTypes "github.com/dexon-foundation/dexon-consensus-core/core/types/dkg"

    "github.com/dexon-foundation/dexon/common"
    "github.com/dexon-foundation/dexon/core/types"
    "github.com/dexon-foundation/dexon/log"
    "github.com/dexon-foundation/dexon/p2p"
    "github.com/dexon-foundation/dexon/p2p/enode"
    "github.com/dexon-foundation/dexon/p2p/enr"
    "github.com/dexon-foundation/dexon/rlp"
)

var (
    errClosed            = errors.New("peer set is closed")
    errAlreadyRegistered = errors.New("peer is already registered")
    errNotRegistered     = errors.New("peer is not registered")
)

const (
    maxKnownTxs    = 32768 // Maximum transactions hashes to keep in the known list (prevent DOS)
    maxKnownMetas  = 32768 // Maximum metas hashes to keep in the known list (prevent DOS)
    maxKnownBlocks = 1024  // Maximum block hashes to keep in the known list (prevent DOS)

    maxKnownLatticeBLocks       = 2048
    maxKnownVotes               = 2048
    maxKnownAgreements          = 10240
    maxKnownRandomnesses        = 10240
    maxKnownDKGPrivateShare     = 1024 // this related to DKG Size
    maxKnownDKGPartialSignature = 1024 // this related to DKG Size

    // maxQueuedTxs is the maximum number of transaction lists to queue up before
    // dropping broadcasts. This is a sensitive number as a transaction list might
    // contain a single transaction, or thousands.
    maxQueuedTxs = 128

    maxQueuedMetas = 512

    // maxQueuedProps is the maximum number of block propagations to queue up before
    // dropping broadcasts. There's not much point in queueing stale blocks, so a few
    // that might cover uncles should be enough.
    maxQueuedProps = 4

    // maxQueuedAnns is the maximum number of block announcements to queue up before
    // dropping broadcasts. Similarly to block propagations, there's no point to queue
    // above some healthy uncle limit, so use that.
    maxQueuedAnns = 4

    maxQueuedLatticeBlocks        = 16
    maxQueuedVotes                = 128
    maxQueuedAgreements           = 16
    maxQueuedRandomnesses         = 16
    maxQueuedDKGPrivateShare      = 16
    maxQueuedDKGParitialSignature = 16

    handshakeTimeout = 5 * time.Second

    groupNodeNum = 3
)

// PeerInfo represents a short summary of the Ethereum sub-protocol metadata known
// about a connected peer.
type PeerInfo struct {
    Version    int      `json:"version"`    // Ethereum protocol version negotiated
    Difficulty *big.Int `json:"difficulty"` // Total difficulty of the peer's blockchain
    Head       string   `json:"head"`       // SHA3 hash of the peer's best owned block
}

// propEvent is a block propagation, waiting for its turn in the broadcast queue.
type propEvent struct {
    block *types.Block
    td    *big.Int
}

type setType uint32

const (
    dkgset = iota
    notaryset
)

type peerLabel struct {
    set     setType
    chainID uint32
    round   uint64
}

type peer struct {
    id string

    *p2p.Peer
    rw p2p.MsgReadWriter

    version int // Protocol version negotiated

    head common.Hash
    td   *big.Int
    lock sync.RWMutex

    knownTxs                   mapset.Set // Set of transaction hashes known to be known by this peer
    knownMetas                 mapset.Set // Set of node metas known to be known by this peer
    knownBlocks                mapset.Set // Set of block hashes known to be known by this peer
    knownLatticeBlocks         mapset.Set
    knownVotes                 mapset.Set
    knownAgreements            mapset.Set
    knownRandomnesses          mapset.Set
    knownDKGPrivateShares      mapset.Set
    knownDKGPartialSignatures  mapset.Set
    queuedTxs                  chan []*types.Transaction // Queue of transactions to broadcast to the peer
    queuedMetas                chan []*NodeMeta          // Queue of node metas to broadcast to the peer
    queuedProps                chan *propEvent           // Queue of blocks to broadcast to the peer
    queuedAnns                 chan *types.Block         // Queue of blocks to announce to the peer
    queuedLatticeBlocks        chan *coreTypes.Block
    queuedVotes                chan *coreTypes.Vote
    queuedAgreements           chan *coreTypes.AgreementResult
    queuedRandomnesses         chan *coreTypes.BlockRandomnessResult
    queuedDKGPrivateShares     chan *dkgTypes.PrivateShare
    queuedDKGPartialSignatures chan *dkgTypes.PartialSignature
    term                       chan struct{} // Termination channel to stop the broadcaster
}

func newPeer(version int, p *p2p.Peer, rw p2p.MsgReadWriter) *peer {
    return &peer{
        Peer:                       p,
        rw:                         rw,
        version:                    version,
        id:                         p.ID().String(),
        knownTxs:                   mapset.NewSet(),
        knownMetas:                 mapset.NewSet(),
        knownBlocks:                mapset.NewSet(),
        knownLatticeBlocks:         mapset.NewSet(),
        knownVotes:                 mapset.NewSet(),
        knownAgreements:            mapset.NewSet(),
        knownRandomnesses:          mapset.NewSet(),
        knownDKGPrivateShares:      mapset.NewSet(),
        knownDKGPartialSignatures:  mapset.NewSet(),
        queuedTxs:                  make(chan []*types.Transaction, maxQueuedTxs),
        queuedMetas:                make(chan []*NodeMeta, maxQueuedMetas),
        queuedProps:                make(chan *propEvent, maxQueuedProps),
        queuedAnns:                 make(chan *types.Block, maxQueuedAnns),
        queuedLatticeBlocks:        make(chan *coreTypes.Block, maxQueuedLatticeBlocks),
        queuedVotes:                make(chan *coreTypes.Vote, maxQueuedVotes),
        queuedAgreements:           make(chan *coreTypes.AgreementResult, maxQueuedAgreements),
        queuedRandomnesses:         make(chan *coreTypes.BlockRandomnessResult, maxQueuedRandomnesses),
        queuedDKGPrivateShares:     make(chan *dkgTypes.PrivateShare, maxQueuedDKGPrivateShare),
        queuedDKGPartialSignatures: make(chan *dkgTypes.PartialSignature, maxQueuedDKGParitialSignature),
        term: make(chan struct{}),
    }
}

// broadcast is a write loop that multiplexes block propagations, announcements,
// transaction and notary node metas broadcasts into the remote peer.
// The goal is to have an async writer that does not lock up node internals.
func (p *peer) broadcast() {
    for {
        select {
        case txs := <-p.queuedTxs:
            if err := p.SendTransactions(txs); err != nil {
                return
            }
            p.Log().Trace("Broadcast transactions", "count", len(txs))

        case metas := <-p.queuedMetas:
            if err := p.SendNodeMetas(metas); err != nil {
                return
            }
            p.Log().Trace("Broadcast node metas", "count", len(metas))

        case prop := <-p.queuedProps:
            if err := p.SendNewBlock(prop.block, prop.td); err != nil {
                return
            }
            p.Log().Trace("Propagated block", "number", prop.block.Number(), "hash", prop.block.Hash(), "td", prop.td)

        case block := <-p.queuedAnns:
            if err := p.SendNewBlockHashes([]common.Hash{block.Hash()}, []uint64{block.NumberU64()}); err != nil {
                return
            }
            p.Log().Trace("Announced block", "number", block.Number(), "hash", block.Hash())
        case block := <-p.queuedLatticeBlocks:
            if err := p.SendLatticeBlock(block); err != nil {
                return
            }
            p.Log().Trace("Broadcast lattice block")
        case vote := <-p.queuedVotes:
            if err := p.SendVote(vote); err != nil {
                return
            }
            p.Log().Trace("Broadcast vote", "vote", vote.String(), "hash", rlpHash(vote))
        case agreement := <-p.queuedAgreements:
            if err := p.SendAgreement(agreement); err != nil {
                return
            }
            p.Log().Trace("Broadcast agreement")
        case randomness := <-p.queuedRandomnesses:
            if err := p.SendRandomness(randomness); err != nil {
                return
            }
            p.Log().Trace("Broadcast randomness")
        case privateShare := <-p.queuedDKGPrivateShares:
            if err := p.SendDKGPrivateShare(privateShare); err != nil {
                return
            }
            p.Log().Trace("Broadcast DKG private share")
        case psig := <-p.queuedDKGPartialSignatures:
            if err := p.SendDKGPartialSignature(psig); err != nil {
                return
            }
            p.Log().Trace("Broadcast DKG partial signature")
        case <-p.term:
            return
        }
    }
}

// close signals the broadcast goroutine to terminate.
func (p *peer) close() {
    close(p.term)
}

// Info gathers and returns a collection of metadata known about a peer.
func (p *peer) Info() *PeerInfo {
    hash, td := p.Head()

    return &PeerInfo{
        Version:    p.version,
        Difficulty: td,
        Head:       hash.Hex(),
    }
}

// Head retrieves a copy of the current head hash and total difficulty of the
// peer.
func (p *peer) Head() (hash common.Hash, td *big.Int) {
    p.lock.RLock()
    defer p.lock.RUnlock()

    copy(hash[:], p.head[:])
    return hash, new(big.Int).Set(p.td)
}

// SetHead updates the head hash and total difficulty of the peer.
func (p *peer) SetHead(hash common.Hash, td *big.Int) {
    p.lock.Lock()
    defer p.lock.Unlock()

    copy(p.head[:], hash[:])
    p.td.Set(td)
}

// MarkBlock marks a block as known for the peer, ensuring that the block will
// never be propagated to this particular peer.
func (p *peer) MarkBlock(hash common.Hash) {
    // If we reached the memory allowance, drop a previously known block hash
    for p.knownBlocks.Cardinality() >= maxKnownBlocks {
        p.knownBlocks.Pop()
    }
    p.knownBlocks.Add(hash)
}

// MarkTransaction marks a transaction as known for the peer, ensuring that it
// will never be propagated to this particular peer.
func (p *peer) MarkTransaction(hash common.Hash) {
    // If we reached the memory allowance, drop a previously known transaction hash
    for p.knownTxs.Cardinality() >= maxKnownTxs {
        p.knownTxs.Pop()
    }
    p.knownTxs.Add(hash)
}

func (p *peer) MarkNodeMeta(hash common.Hash) {
    for p.knownMetas.Cardinality() >= maxKnownMetas {
        p.knownMetas.Pop()
    }
    p.knownMetas.Add(hash)
}

// SendTransactions sends transactions to the peer and includes the hashes
// in its transaction hash set for future reference.
func (p *peer) SendTransactions(txs types.Transactions) error {
    for _, tx := range txs {
        p.knownTxs.Add(tx.Hash())
    }
    return p2p.Send(p.rw, TxMsg, txs)
}

// AsyncSendTransactions queues list of transactions propagation to a remote
// peer. If the peer's broadcast queue is full, the event is silently dropped.
func (p *peer) AsyncSendTransactions(txs []*types.Transaction) {
    select {
    case p.queuedTxs <- txs:
        for _, tx := range txs {
            p.knownTxs.Add(tx.Hash())
        }
    default:
        p.Log().Debug("Dropping transaction propagation", "count", len(txs))
    }
}

// SendNodeMetas sends the metas to the peer and includes the hashes
// in its metas hash set for future reference.
func (p *peer) SendNodeMetas(metas []*NodeMeta) error {
    for _, meta := range metas {
        p.knownMetas.Add(meta.Hash())
    }
    return p2p.Send(p.rw, MetaMsg, metas)
}

// AsyncSendNodeMeta queues list of notary node meta propagation to a
// remote peer. If the peer's broadcast queue is full, the event is silently
// dropped.
func (p *peer) AsyncSendNodeMetas(metas []*NodeMeta) {
    select {
    case p.queuedMetas <- metas:
        for _, meta := range metas {
            p.knownMetas.Add(meta.Hash())
        }
    default:
        p.Log().Debug("Dropping node meta propagation", "count", len(metas))
    }
}

// SendNewBlockHashes announces the availability of a number of blocks through
// a hash notification.
func (p *peer) SendNewBlockHashes(hashes []common.Hash, numbers []uint64) error {
    for _, hash := range hashes {
        p.knownBlocks.Add(hash)
    }
    request := make(newBlockHashesData, len(hashes))
    for i := 0; i < len(hashes); i++ {
        request[i].Hash = hashes[i]
        request[i].Number = numbers[i]
    }
    return p2p.Send(p.rw, NewBlockHashesMsg, request)
}

// AsyncSendNewBlockHash queues the availability of a block for propagation to a
// remote peer. If the peer's broadcast queue is full, the event is silently
// dropped.
func (p *peer) AsyncSendNewBlockHash(block *types.Block) {
    select {
    case p.queuedAnns <- block:
        p.knownBlocks.Add(block.Hash())
    default:
        p.Log().Debug("Dropping block announcement", "number", block.NumberU64(), "hash", block.Hash())
    }
}

// SendNewBlock propagates an entire block to a remote peer.
func (p *peer) SendNewBlock(block *types.Block, td *big.Int) error {
    p.knownBlocks.Add(block.Hash())
    return p2p.Send(p.rw, NewBlockMsg, []interface{}{block, td})
}

// AsyncSendNewBlock queues an entire block for propagation to a remote peer. If
// the peer's broadcast queue is full, the event is silently dropped.
func (p *peer) AsyncSendNewBlock(block *types.Block, td *big.Int) {
    select {
    case p.queuedProps <- &propEvent{block: block, td: td}:
        p.knownBlocks.Add(block.Hash())
    default:
        p.Log().Debug("Dropping block propagation", "number", block.NumberU64(), "hash", block.Hash())
    }
}

func (p *peer) SendLatticeBlock(block *coreTypes.Block) error {
    p.knownLatticeBlocks.Add(rlpHash(block))
    return p2p.Send(p.rw, LatticeBlockMsg, block)
}

func (p *peer) AsyncSendLatticeBlock(block *coreTypes.Block) {
    select {
    case p.queuedLatticeBlocks <- block:
        p.knownLatticeBlocks.Add(rlpHash(block))
    default:
        p.Log().Debug("Dropping lattice block propagation")
    }
}

func (p *peer) SendVote(vote *coreTypes.Vote) error {
    p.knownVotes.Add(rlpHash(vote))
    return p2p.Send(p.rw, VoteMsg, vote)
}

func (p *peer) AsyncSendVote(vote *coreTypes.Vote) {
    select {
    case p.queuedVotes <- vote:
        p.knownVotes.Add(rlpHash(vote))
    default:
        p.Log().Debug("Dropping vote propagation")
    }
}

func (p *peer) SendAgreement(agreement *coreTypes.AgreementResult) error {
    p.knownAgreements.Add(rlpHash(agreement))
    return p2p.Send(p.rw, AgreementMsg, agreement)
}

func (p *peer) AsyncSendAgreement(agreement *coreTypes.AgreementResult) {
    select {
    case p.queuedAgreements <- agreement:
        p.knownAgreements.Add(rlpHash(agreement))
    default:
        p.Log().Debug("Dropping agreement result")
    }
}

func (p *peer) SendRandomness(randomness *coreTypes.BlockRandomnessResult) error {
    p.knownRandomnesses.Add(rlpHash(randomness))
    return p2p.Send(p.rw, RandomnessMsg, randomness)
}

func (p *peer) AsyncSendRandomness(randomness *coreTypes.BlockRandomnessResult) {
    select {
    case p.queuedRandomnesses <- randomness:
        p.knownRandomnesses.Add(rlpHash(randomness))
    default:
        p.Log().Debug("Dropping randomness result")
    }
}

func (p *peer) SendDKGPrivateShare(privateShare *dkgTypes.PrivateShare) error {
    p.knownDKGPrivateShares.Add(rlpHash(privateShare))
    return p2p.Send(p.rw, DKGPrivateShareMsg, privateShare)
}

func (p *peer) AsyncSendDKGPrivateShare(privateShare *dkgTypes.PrivateShare) {
    select {
    case p.queuedDKGPrivateShares <- privateShare:
        p.knownDKGPrivateShares.Add(rlpHash(privateShare))
    default:
        p.Log().Debug("Dropping DKG private share")
    }
}

func (p *peer) SendDKGPartialSignature(psig *dkgTypes.PartialSignature) error {
    p.knownDKGPartialSignatures.Add(rlpHash(psig))
    return p2p.Send(p.rw, DKGPartialSignatureMsg, psig)
}

func (p *peer) AsyncSendDKGPartialSignature(psig *dkgTypes.PartialSignature) {
    select {
    case p.queuedDKGPartialSignatures <- psig:
        p.knownDKGPartialSignatures.Add(rlpHash(psig))
    default:
        p.Log().Debug("Dropping DKG partial signature")
    }
}

// SendBlockHeaders sends a batch of block headers to the remote peer.
func (p *peer) SendBlockHeaders(headers []*types.Header) error {
    return p2p.Send(p.rw, BlockHeadersMsg, headers)
}

// SendBlockBodies sends a batch of block contents to the remote peer.
func (p *peer) SendBlockBodies(bodies []*blockBody) error {
    return p2p.Send(p.rw, BlockBodiesMsg, blockBodiesData(bodies))
}

// SendBlockBodiesRLP sends a batch of block contents to the remote peer from
// an already RLP encoded format.
func (p *peer) SendBlockBodiesRLP(bodies []rlp.RawValue) error {
    return p2p.Send(p.rw, BlockBodiesMsg, bodies)
}

// SendNodeDataRLP sends a batch of arbitrary internal data, corresponding to the
// hashes requested.
func (p *peer) SendNodeData(data [][]byte) error {
    return p2p.Send(p.rw, NodeDataMsg, data)
}

// SendReceiptsRLP sends a batch of transaction receipts, corresponding to the
// ones requested from an already RLP encoded format.
func (p *peer) SendReceiptsRLP(receipts []rlp.RawValue) error {
    return p2p.Send(p.rw, ReceiptsMsg, receipts)
}

// RequestOneHeader is a wrapper around the header query functions to fetch a
// single header. It is used solely by the fetcher.
func (p *peer) RequestOneHeader(hash common.Hash) error {
    p.Log().Debug("Fetching single header", "hash", hash)
    return p2p.Send(p.rw, GetBlockHeadersMsg, &getBlockHeadersData{Origin: hashOrNumber{Hash: hash}, Amount: uint64(1), Skip: uint64(0), Reverse: false})
}

// RequestHeadersByHash fetches a batch of blocks' headers corresponding to the
// specified header query, based on the hash of an origin block.
func (p *peer) RequestHeadersByHash(origin common.Hash, amount int, skip int, reverse bool) error {
    p.Log().Debug("Fetching batch of headers", "count", amount, "fromhash", origin, "skip", skip, "reverse", reverse)
    return p2p.Send(p.rw, GetBlockHeadersMsg, &getBlockHeadersData{Origin: hashOrNumber{Hash: origin}, Amount: uint64(amount), Skip: uint64(skip), Reverse: reverse})
}

// RequestHeadersByNumber fetches a batch of blocks' headers corresponding to the
// specified header query, based on the number of an origin block.
func (p *peer) RequestHeadersByNumber(origin uint64, amount int, skip int, reverse bool) error {
    p.Log().Debug("Fetching batch of headers", "count", amount, "fromnum", origin, "skip", skip, "reverse", reverse)
    return p2p.Send(p.rw, GetBlockHeadersMsg, &getBlockHeadersData{Origin: hashOrNumber{Number: origin}, Amount: uint64(amount), Skip: uint64(skip), Reverse: reverse})
}

// RequestBodies fetches a batch of blocks' bodies corresponding to the hashes
// specified.
func (p *peer) RequestBodies(hashes []common.Hash) error {
    p.Log().Debug("Fetching batch of block bodies", "count", len(hashes))
    return p2p.Send(p.rw, GetBlockBodiesMsg, hashes)
}

// RequestNodeData fetches a batch of arbitrary data from a node's known state
// data, corresponding to the specified hashes.
func (p *peer) RequestNodeData(hashes []common.Hash) error {
    p.Log().Debug("Fetching batch of state data", "count", len(hashes))
    return p2p.Send(p.rw, GetNodeDataMsg, hashes)
}

// RequestReceipts fetches a batch of transaction receipts from a remote node.
func (p *peer) RequestReceipts(hashes []common.Hash) error {
    p.Log().Debug("Fetching batch of receipts", "count", len(hashes))
    return p2p.Send(p.rw, GetReceiptsMsg, hashes)
}

// Handshake executes the eth protocol handshake, negotiating version number,
// network IDs, difficulties, head and genesis blocks.
func (p *peer) Handshake(network uint64, td *big.Int, head common.Hash, genesis common.Hash) error {
    // Send out own handshake in a new thread
    errc := make(chan error, 2)
    var status statusData // safe to read after two values have been received from errc

    go func() {
        errc <- p2p.Send(p.rw, StatusMsg, &statusData{
            ProtocolVersion: uint32(p.version),
            NetworkId:       network,
            TD:              td,
            CurrentBlock:    head,
            GenesisBlock:    genesis,
        })
    }()
    go func() {
        errc <- p.readStatus(network, &status, genesis)
    }()
    timeout := time.NewTimer(handshakeTimeout)
    defer timeout.Stop()
    for i := 0; i < 2; i++ {
        select {
        case err := <-errc:
            if err != nil {
                return err
            }
        case <-timeout.C:
            return p2p.DiscReadTimeout
        }
    }
    p.td, p.head = status.TD, status.CurrentBlock
    return nil
}

func (p *peer) readStatus(network uint64, status *statusData, genesis common.Hash) (err error) {
    msg, err := p.rw.ReadMsg()
    if err != nil {
        return err
    }
    if msg.Code != StatusMsg {
        return errResp(ErrNoStatusMsg, "first msg has code %x (!= %x)", msg.Code, StatusMsg)
    }
    if msg.Size > ProtocolMaxMsgSize {
        return errResp(ErrMsgTooLarge, "%v > %v", msg.Size, ProtocolMaxMsgSize)
    }
    // Decode the handshake and make sure everything matches
    if err := msg.Decode(&status); err != nil {
        return errResp(ErrDecode, "msg %v: %v", msg, err)
    }
    if status.GenesisBlock != genesis {
        return errResp(ErrGenesisBlockMismatch, "%x (!= %x)", status.GenesisBlock[:8], genesis[:8])
    }
    if status.NetworkId != network {
        return errResp(ErrNetworkIdMismatch, "%d (!= %d)", status.NetworkId, network)
    }
    if int(status.ProtocolVersion) != p.version {
        return errResp(ErrProtocolVersionMismatch, "%d (!= %d)", status.ProtocolVersion, p.version)
    }
    return nil
}

// String implements fmt.Stringer.
func (p *peer) String() string {
    return fmt.Sprintf("Peer %s [%s]", p.id,
        fmt.Sprintf("dex/%2d", p.version),
    )
}

// peerSet represents the collection of active peers currently participating in
// the Ethereum sub-protocol.
type peerSet struct {
    peers  map[string]*peer
    lock   sync.RWMutex
    closed bool
    tab    *nodeTable

    srvr          p2pServer
    gov           governance
    peer2Labels   map[string]map[peerLabel]struct{}
    label2Peers   map[peerLabel]map[string]struct{}
    history       map[uint64]struct{}
    notaryHistory map[uint64]struct{}
    dkgHistory    map[uint64]struct{}
}

// newPeerSet creates a new peer set to track the active participants.
func newPeerSet(gov governance, srvr p2pServer, tab *nodeTable) *peerSet {
    return &peerSet{
        peers:         make(map[string]*peer),
        gov:           gov,
        srvr:          srvr,
        tab:           tab,
        peer2Labels:   make(map[string]map[peerLabel]struct{}),
        label2Peers:   make(map[peerLabel]map[string]struct{}),
        history:       make(map[uint64]struct{}),
        notaryHistory: make(map[uint64]struct{}),
        dkgHistory:    make(map[uint64]struct{}),
    }
}

// Register injects a new peer into the working set, or returns an error if the
// peer is already known. If a new peer it registered, its broadcast loop is also
// started.
func (ps *peerSet) Register(p *peer) error {
    ps.lock.Lock()
    defer ps.lock.Unlock()

    if ps.closed {
        return errClosed
    }
    if _, ok := ps.peers[p.id]; ok {
        return errAlreadyRegistered
    }
    ps.peers[p.id] = p
    go p.broadcast()

    return nil
}

// Unregister removes a remote peer from the active set, disabling any further
// actions to/from that particular entity.
func (ps *peerSet) Unregister(id string) error {
    ps.lock.Lock()
    defer ps.lock.Unlock()

    p, ok := ps.peers[id]
    if !ok {
        return errNotRegistered
    }
    delete(ps.peers, id)
    p.close()

    return nil
}

// Peer retrieves the registered peer with the given id.
func (ps *peerSet) Peer(id string) *peer {
    ps.lock.RLock()
    defer ps.lock.RUnlock()

    return ps.peers[id]
}

// Len returns if the current number of peers in the set.
func (ps *peerSet) Len() int {
    ps.lock.RLock()
    defer ps.lock.RUnlock()

    return len(ps.peers)
}

// PeersWithoutBlock retrieves a list of peers that do not have a given block in
// their set of known hashes.
func (ps *peerSet) PeersWithoutBlock(hash common.Hash) []*peer {
    ps.lock.RLock()
    defer ps.lock.RUnlock()

    list := make([]*peer, 0, len(ps.peers))
    for _, p := range ps.peers {
        if !p.knownBlocks.Contains(hash) {
            list = append(list, p)
        }
    }
    return list
}

// PeersWithoutTx retrieves a list of peers that do not have a given transaction
// in their set of known hashes.
func (ps *peerSet) PeersWithoutTx(hash common.Hash) []*peer {
    ps.lock.RLock()
    defer ps.lock.RUnlock()

    list := make([]*peer, 0, len(ps.peers))
    for _, p := range ps.peers {
        if !p.knownTxs.Contains(hash) {
            list = append(list, p)
        }
    }
    return list
}

func (ps *peerSet) PeersWithLabel(label peerLabel) []*peer {
    ps.lock.RLock()
    defer ps.lock.RUnlock()
    list := make([]*peer, 0, len(ps.label2Peers[label]))
    for id := range ps.label2Peers[label] {
        if p, ok := ps.peers[id]; ok {
            list = append(list, p)
        }
    }
    return list
}

func (ps *peerSet) PeersWithoutVote(hash common.Hash, label peerLabel) []*peer {
    ps.lock.RLock()
    defer ps.lock.RUnlock()

    list := make([]*peer, 0, len(ps.label2Peers[label]))
    for id := range ps.label2Peers[label] {
        if p, ok := ps.peers[id]; ok {
            if !p.knownVotes.Contains(hash) {
                list = append(list, p)
            }
        }
    }
    return list
}

// PeersWithoutNodeMeta retrieves a list of peers that do not have a
// given meta in their set of known hashes.
func (ps *peerSet) PeersWithoutNodeMeta(hash common.Hash) []*peer {
    ps.lock.RLock()
    defer ps.lock.RUnlock()
    list := make([]*peer, 0, len(ps.peers))
    for _, p := range ps.peers {
        if !p.knownMetas.Contains(hash) {
            list = append(list, p)
        }
    }
    return list
}

func (ps *peerSet) PeersWithoutLatticeBlock(hash common.Hash) []*peer {
    ps.lock.RLock()
    defer ps.lock.RUnlock()
    list := make([]*peer, 0, len(ps.peers))
    for _, p := range ps.peers {
        if !p.knownLatticeBlocks.Contains(hash) {
            list = append(list, p)
        }
    }
    return list
}

func (ps *peerSet) PeersWithoutAgreement(hash common.Hash) []*peer {
    ps.lock.RLock()
    defer ps.lock.RUnlock()
    list := make([]*peer, 0, len(ps.peers))
    for _, p := range ps.peers {
        if !p.knownAgreements.Contains(hash) {
            list = append(list, p)
        }
    }
    return list
}

func (ps *peerSet) PeersWithoutRandomness(hash common.Hash) []*peer {
    ps.lock.RLock()
    defer ps.lock.RUnlock()
    list := make([]*peer, 0, len(ps.peers))
    for _, p := range ps.peers {
        if !p.knownRandomnesses.Contains(hash) {
            list = append(list, p)
        }
    }
    return list
}

func (ps *peerSet) PeersWithoutDKGPartialSignature(hash common.Hash) []*peer {
    ps.lock.RLock()
    defer ps.lock.RUnlock()
    list := make([]*peer, 0, len(ps.peers))
    for _, p := range ps.peers {
        if !p.knownDKGPartialSignatures.Contains(hash) {
            list = append(list, p)
        }
    }
    return list
}

// BestPeer retrieves the known peer with the currently highest total difficulty.
func (ps *peerSet) BestPeer() *peer {
    ps.lock.RLock()
    defer ps.lock.RUnlock()

    var (
        bestPeer *peer
        bestTd   *big.Int
    )
    for _, p := range ps.peers {
        if _, td := p.Head(); bestPeer == nil || td.Cmp(bestTd) > 0 {
            bestPeer, bestTd = p, td
        }
    }
    return bestPeer
}

// Close disconnects all peers.
// No new peers can be registered after Close has returned.
func (ps *peerSet) Close() {
    ps.lock.Lock()
    defer ps.lock.Unlock()

    for _, p := range ps.peers {
        p.Disconnect(p2p.DiscQuitting)
    }
    ps.closed = true
}

func (ps *peerSet) BuildConnection(round uint64) {
    ps.lock.Lock()
    defer ps.lock.Unlock()
    defer ps.dumpPeerLabel(fmt.Sprintf("BuildConnection: %d", round))

    ps.history[round] = struct{}{}

    selfID := ps.srvr.Self().ID().String()

    dkgIDs, err := ps.gov.DKGSet(round)
    if err != nil {
        log.Error("get dkg set fail", "round", round, "err", err)
    }

    // build dkg connection
    _, inDKGSet := dkgIDs[selfID]
    if inDKGSet {
        delete(dkgIDs, selfID)
        dkgLabel := peerLabel{set: dkgset, round: round}
        for id := range dkgIDs {
            ps.addDirectPeer(id, dkgLabel)
        }
    }

    var inOneNotarySet bool
    for cid := uint32(0); cid < ps.gov.GetNumChains(round); cid++ {
        notaryIDs, err := ps.gov.NotarySet(round, cid)
        if err != nil {
            log.Error("get notary set fail",
                "round", round, "chain id", cid, "err", err)
            continue
        }

        label := peerLabel{set: notaryset, chainID: cid, round: round}
        // not in notary set, add group
        if _, ok := notaryIDs[selfID]; !ok {
            var nodes []*enode.Node
            for id := range notaryIDs {
                nodes = append(nodes, ps.newNode(id))
                ps.addLabel(id, label)
            }
            ps.srvr.AddGroup(notarySetName(cid, round), nodes, groupNodeNum)
            continue
        }

        delete(notaryIDs, selfID)
        for id := range notaryIDs {
            ps.addDirectPeer(id, label)
        }
        inOneNotarySet = true
    }

    // build some connections to DKG nodes
    if !inDKGSet && inOneNotarySet {
        var nodes []*enode.Node
        label := peerLabel{set: dkgset, round: round}
        for id := range dkgIDs {
            nodes = append(nodes, ps.newNode(id))
            ps.addLabel(id, label)
        }
        ps.srvr.AddGroup(dkgSetName(round), nodes, groupNodeNum)
    }
}

func (ps *peerSet) ForgetConnection(round uint64) {
    ps.lock.Lock()
    defer ps.lock.Unlock()
    defer ps.dumpPeerLabel(fmt.Sprintf("ForgetConnection: %d", round))

    for r := range ps.history {
        if r <= round {
            ps.forgetConnection(round)
            delete(ps.history, r)
        }
    }
}

func (ps *peerSet) forgetConnection(round uint64) {
    selfID := ps.srvr.Self().ID().String()
    dkgIDs, err := ps.gov.DKGSet(round)
    if err != nil {
        log.Error("get dkg set fail", "round", round, "err", err)
    }

    _, inDKGSet := dkgIDs[selfID]
    if inDKGSet {
        delete(dkgIDs, selfID)
        label := peerLabel{set: dkgset, round: round}
        for id := range dkgIDs {
            ps.removeDirectPeer(id, label)
        }
    }

    var inOneNotarySet bool
    for cid := uint32(0); cid < ps.gov.GetNumChains(round); cid++ {
        notaryIDs, err := ps.gov.NotarySet(round, cid)
        if err != nil {
            log.Error("get notary set fail",
                "round", round, "chain id", cid, "err", err)
            continue
        }

        label := peerLabel{set: notaryset, chainID: cid, round: round}

        // not in notary set, add group
        if _, ok := notaryIDs[selfID]; !ok {
            var nodes []*enode.Node
            for id := range notaryIDs {
                nodes = append(nodes, ps.newNode(id))
                ps.removeLabel(id, label)
            }
            ps.srvr.RemoveGroup(notarySetName(cid, round))
            continue
        }

        delete(notaryIDs, selfID)
        for id := range notaryIDs {
            ps.removeDirectPeer(id, label)
        }
        inOneNotarySet = true
    }

    // build some connections to DKG nodes
    if !inDKGSet && inOneNotarySet {
        var nodes []*enode.Node
        label := peerLabel{set: dkgset, round: round}
        for id := range dkgIDs {
            nodes = append(nodes, ps.newNode(id))
            ps.removeLabel(id, label)
        }
        ps.srvr.RemoveGroup(dkgSetName(round))
    }
}

func (ps *peerSet) BuildNotaryConn(round uint64) {
    ps.lock.Lock()
    defer ps.lock.Unlock()
    defer ps.dumpPeerLabel(fmt.Sprintf("BuildNotaryConn: %d", round))

    if _, ok := ps.notaryHistory[round]; ok {
        return
    }

    ps.notaryHistory[round] = struct{}{}

    selfID := ps.srvr.Self().ID().String()
    for chainID := uint32(0); chainID < ps.gov.GetNumChains(round); chainID++ {
        s, err := ps.gov.NotarySet(round, chainID)
        if err != nil {
            log.Error("get notary set fail",
                "round", round, "chain id", chainID, "err", err)
            continue
        }

        // not in notary set, add group
        if _, ok := s[selfID]; !ok {
            var nodes []*enode.Node
            for id := range s {
                nodes = append(nodes, ps.newNode(id))
            }
            ps.srvr.AddGroup(notarySetName(chainID, round), nodes, groupNodeNum)
            continue
        }

        label := peerLabel{
            set:     notaryset,
            chainID: chainID,
            round:   round,
        }
        delete(s, selfID)
        for id := range s {
            ps.addDirectPeer(id, label)
        }
    }
}

func (ps *peerSet) dumpPeerLabel(s string) {
    log.Trace(s, "peer num", len(ps.peers))
    for id, labels := range ps.peer2Labels {
        _, ok := ps.peers[id]
        for label := range labels {
            log.Trace(s, "connected", ok, "id", id[:16],
                "round", label.round, "cid", label.chainID, "set", label.set)
        }
    }
}

func (ps *peerSet) ForgetNotaryConn(round uint64) {
    ps.lock.Lock()
    defer ps.lock.Unlock()
    defer ps.dumpPeerLabel(fmt.Sprintf("ForgetNotaryConn: %d", round))

    // forget all the rounds before the given round
    for r := range ps.notaryHistory {
        if r <= round {
            ps.forgetNotaryConn(r)
            delete(ps.notaryHistory, r)
        }
    }
}

func (ps *peerSet) forgetNotaryConn(round uint64) {
    selfID := ps.srvr.Self().ID().String()
    for chainID := uint32(0); chainID < ps.gov.GetNumChains(round); chainID++ {
        s, err := ps.gov.NotarySet(round, chainID)
        if err != nil {
            log.Error("get notary set fail",
                "round", round, "chain id", chainID, "err", err)
            continue
        }
        if _, ok := s[selfID]; !ok {
            ps.srvr.RemoveGroup(notarySetName(chainID, round))
            continue
        }

        label := peerLabel{
            set:     notaryset,
            chainID: chainID,
            round:   round,
        }
        delete(s, selfID)
        for id := range s {
            ps.removeDirectPeer(id, label)
        }
    }
}

func notarySetName(chainID uint32, round uint64) string {
    return fmt.Sprintf("%d-%d-notaryset", chainID, round)
}

func dkgSetName(round uint64) string {
    return fmt.Sprintf("%d-dkgset", round)
}

func (ps *peerSet) BuildDKGConn(round uint64) {
    ps.lock.Lock()
    defer ps.lock.Unlock()
    defer ps.dumpPeerLabel(fmt.Sprintf("BuildDKGConn: %d", round))
    selfID := ps.srvr.Self().ID().String()
    s, err := ps.gov.DKGSet(round)
    if err != nil {
        log.Error("get dkg set fail", "round", round)
        return
    }

    if _, ok := s[selfID]; !ok {
        return
    }
    ps.dkgHistory[round] = struct{}{}

    delete(s, selfID)
    for id := range s {
        ps.addDirectPeer(id, peerLabel{
            set:   dkgset,
            round: round,
        })
    }
}

func (ps *peerSet) ForgetDKGConn(round uint64) {
    ps.lock.Lock()
    defer ps.lock.Unlock()
    defer ps.dumpPeerLabel(fmt.Sprintf("ForgetDKGConn: %d", round))

    // forget all the rounds before the given round
    for r := range ps.dkgHistory {
        if r <= round {
            ps.forgetDKGConn(r)
            delete(ps.dkgHistory, r)
        }
    }
}

func (ps *peerSet) forgetDKGConn(round uint64) {
    selfID := ps.srvr.Self().ID().String()
    s, err := ps.gov.DKGSet(round)
    if err != nil {
        log.Error("get dkg set fail", "round", round)
        return
    }
    if _, ok := s[selfID]; !ok {
        return
    }

    delete(s, selfID)
    label := peerLabel{
        set:   dkgset,
        round: round,
    }
    for id := range s {
        ps.removeDirectPeer(id, label)
    }
}

// make sure the ps.lock is held
func (ps *peerSet) addDirectPeer(id string, label peerLabel) {
    ps.addLabel(id, label)
    ps.srvr.AddDirectPeer(ps.newNode(id))
}

// make sure the ps.lock is held
func (ps *peerSet) removeDirectPeer(id string, label peerLabel) {
    ps.removeLabel(id, label)
    if len(ps.peer2Labels[id]) == 0 {
        ps.srvr.RemoveDirectPeer(ps.newNode(id))
    }
}

// make sure the ps.lock is held
func (ps *peerSet) addLabel(id string, label peerLabel) {
    if _, ok := ps.peer2Labels[id]; !ok {
        ps.peer2Labels[id] = make(map[peerLabel]struct{})
    }
    if _, ok := ps.label2Peers[label]; !ok {
        ps.label2Peers[label] = make(map[string]struct{})
    }
    ps.peer2Labels[id][label] = struct{}{}
    ps.label2Peers[label][id] = struct{}{}
}

// make sure the ps.lock is held
func (ps *peerSet) removeLabel(id string, label peerLabel) {
    delete(ps.peer2Labels[id], label)
    delete(ps.label2Peers[label], id)
    if len(ps.peer2Labels[id]) == 0 {
        delete(ps.peer2Labels, id)
    }
    if len(ps.label2Peers[label]) == 0 {
        delete(ps.label2Peers, label)
    }
}

func (ps *peerSet) newNode(id string) *enode.Node {
    nodeID := enode.HexID(id)
    meta := ps.tab.Get(enode.HexID(id))

    var r enr.Record
    r.Set(enr.ID(nodeID.String()))
    r.Set(enr.IP(meta.IP))
    r.Set(enr.TCP(meta.TCP))
    r.Set(enr.UDP(meta.UDP))

    n, err := enode.New(enode.ValidSchemes, &r)
    if err != nil {
        panic(err)
    }
    return n
}