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
|
// Copyright 2018 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 pss
import (
"bytes"
"context"
"crypto/ecdsa"
"crypto/rand"
"errors"
"fmt"
"hash"
"sync"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/metrics"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/p2p/protocols"
"github.com/ethereum/go-ethereum/rpc"
"github.com/ethereum/go-ethereum/swarm/log"
"github.com/ethereum/go-ethereum/swarm/network"
"github.com/ethereum/go-ethereum/swarm/pot"
"github.com/ethereum/go-ethereum/swarm/storage"
whisper "github.com/ethereum/go-ethereum/whisper/whisperv6"
"golang.org/x/crypto/sha3"
)
const (
defaultPaddingByteSize = 16
DefaultMsgTTL = time.Second * 120
defaultDigestCacheTTL = time.Second * 10
defaultSymKeyCacheCapacity = 512
digestLength = 32 // byte length of digest used for pss cache (currently same as swarm chunk hash)
defaultWhisperWorkTime = 3
defaultWhisperPoW = 0.0000000001
defaultMaxMsgSize = 1024 * 1024
defaultCleanInterval = time.Second * 60 * 10
defaultOutboxCapacity = 100000
pssProtocolName = "pss"
pssVersion = 2
hasherCount = 8
)
var (
addressLength = len(pot.Address{})
)
// cache is used for preventing backwards routing
// will also be instrumental in flood guard mechanism
// and mailbox implementation
type pssCacheEntry struct {
expiresAt time.Time
}
// abstraction to enable access to p2p.protocols.Peer.Send
type senderPeer interface {
Info() *p2p.PeerInfo
ID() enode.ID
Address() []byte
Send(context.Context, interface{}) error
}
// per-key peer related information
// member `protected` prevents garbage collection of the instance
type pssPeer struct {
lastSeen time.Time
address PssAddress
protected bool
}
// Pss configuration parameters
type PssParams struct {
MsgTTL time.Duration
CacheTTL time.Duration
privateKey *ecdsa.PrivateKey
SymKeyCacheCapacity int
AllowRaw bool // If true, enables sending and receiving messages without builtin pss encryption
}
// Sane defaults for Pss
func NewPssParams() *PssParams {
return &PssParams{
MsgTTL: DefaultMsgTTL,
CacheTTL: defaultDigestCacheTTL,
SymKeyCacheCapacity: defaultSymKeyCacheCapacity,
}
}
func (params *PssParams) WithPrivateKey(privatekey *ecdsa.PrivateKey) *PssParams {
params.privateKey = privatekey
return params
}
// Toplevel pss object, takes care of message sending, receiving, decryption and encryption, message handler dispatchers and message forwarding.
//
// Implements node.Service
type Pss struct {
*network.Kademlia // we can get the Kademlia address from this
*KeyStore
privateKey *ecdsa.PrivateKey // pss can have it's own independent key
auxAPIs []rpc.API // builtins (handshake, test) can add APIs
// sending and forwarding
fwdPool map[string]*protocols.Peer // keep track of all peers sitting on the pssmsg routing layer
fwdPoolMu sync.RWMutex
fwdCache map[pssDigest]pssCacheEntry // checksum of unique fields from pssmsg mapped to expiry, cache to determine whether to drop msg
fwdCacheMu sync.RWMutex
cacheTTL time.Duration // how long to keep messages in fwdCache (not implemented)
msgTTL time.Duration
paddingByteSize int
capstring string
outbox chan *PssMsg
// message handling
handlers map[Topic]map[*handler]bool // topic and version based pss payload handlers. See pss.Handle()
handlersMu sync.RWMutex
hashPool sync.Pool
topicHandlerCaps map[Topic]*handlerCaps // caches capabilities of each topic's handlers
topicHandlerCapsMu sync.RWMutex
// process
quitC chan struct{}
}
func (p *Pss) String() string {
return fmt.Sprintf("pss: addr %x, pubkey %v", p.BaseAddr(), common.ToHex(crypto.FromECDSAPub(&p.privateKey.PublicKey)))
}
// Creates a new Pss instance.
//
// In addition to params, it takes a swarm network Kademlia
// and a FileStore storage for message cache storage.
func NewPss(k *network.Kademlia, params *PssParams) (*Pss, error) {
if params.privateKey == nil {
return nil, errors.New("missing private key for pss")
}
cap := p2p.Cap{
Name: pssProtocolName,
Version: pssVersion,
}
ps := &Pss{
Kademlia: k,
KeyStore: loadKeyStore(),
privateKey: params.privateKey,
quitC: make(chan struct{}),
fwdPool: make(map[string]*protocols.Peer),
fwdCache: make(map[pssDigest]pssCacheEntry),
cacheTTL: params.CacheTTL,
msgTTL: params.MsgTTL,
paddingByteSize: defaultPaddingByteSize,
capstring: cap.String(),
outbox: make(chan *PssMsg, defaultOutboxCapacity),
handlers: make(map[Topic]map[*handler]bool),
topicHandlerCaps: make(map[Topic]*handlerCaps),
hashPool: sync.Pool{
New: func() interface{} {
return sha3.NewLegacyKeccak256()
},
},
}
for i := 0; i < hasherCount; i++ {
hashfunc := storage.MakeHashFunc(storage.DefaultHash)()
ps.hashPool.Put(hashfunc)
}
return ps, nil
}
/////////////////////////////////////////////////////////////////////
// SECTION: node.Service interface
/////////////////////////////////////////////////////////////////////
func (p *Pss) Start(srv *p2p.Server) error {
go func() {
ticker := time.NewTicker(defaultCleanInterval)
cacheTicker := time.NewTicker(p.cacheTTL)
defer ticker.Stop()
defer cacheTicker.Stop()
for {
select {
case <-cacheTicker.C:
p.cleanFwdCache()
case <-ticker.C:
p.cleanKeys()
case <-p.quitC:
return
}
}
}()
go func() {
for {
select {
case msg := <-p.outbox:
err := p.forward(msg)
if err != nil {
log.Error(err.Error())
metrics.GetOrRegisterCounter("pss.forward.err", nil).Inc(1)
}
case <-p.quitC:
return
}
}
}()
log.Info("Started Pss")
log.Info("Loaded EC keys", "pubkey", common.ToHex(crypto.FromECDSAPub(p.PublicKey())), "secp256", common.ToHex(crypto.CompressPubkey(p.PublicKey())))
return nil
}
func (p *Pss) Stop() error {
log.Info("Pss shutting down")
close(p.quitC)
return nil
}
var pssSpec = &protocols.Spec{
Name: pssProtocolName,
Version: pssVersion,
MaxMsgSize: defaultMaxMsgSize,
Messages: []interface{}{
PssMsg{},
},
}
func (p *Pss) Protocols() []p2p.Protocol {
return []p2p.Protocol{
{
Name: pssSpec.Name,
Version: pssSpec.Version,
Length: pssSpec.Length(),
Run: p.Run,
},
}
}
func (p *Pss) Run(peer *p2p.Peer, rw p2p.MsgReadWriter) error {
pp := protocols.NewPeer(peer, rw, pssSpec)
p.fwdPoolMu.Lock()
p.fwdPool[peer.Info().ID] = pp
p.fwdPoolMu.Unlock()
return pp.Run(p.handlePssMsg)
}
func (p *Pss) APIs() []rpc.API {
apis := []rpc.API{
{
Namespace: "pss",
Version: "1.0",
Service: NewAPI(p),
Public: true,
},
}
apis = append(apis, p.auxAPIs...)
return apis
}
// add API methods to the pss API
// must be run before node is started
func (p *Pss) addAPI(api rpc.API) {
p.auxAPIs = append(p.auxAPIs, api)
}
// Returns the swarm Kademlia address of the pss node
func (p *Pss) BaseAddr() []byte {
return p.Kademlia.BaseAddr()
}
// Returns the pss node's public key
func (p *Pss) PublicKey() *ecdsa.PublicKey {
return &p.privateKey.PublicKey
}
/////////////////////////////////////////////////////////////////////
// SECTION: Message handling
/////////////////////////////////////////////////////////////////////
func (p *Pss) getTopicHandlerCaps(topic Topic) (hc *handlerCaps, found bool) {
p.topicHandlerCapsMu.RLock()
defer p.topicHandlerCapsMu.RUnlock()
hc, found = p.topicHandlerCaps[topic]
return
}
func (p *Pss) setTopicHandlerCaps(topic Topic, hc *handlerCaps) {
p.topicHandlerCapsMu.Lock()
defer p.topicHandlerCapsMu.Unlock()
p.topicHandlerCaps[topic] = hc
}
// Links a handler function to a Topic
//
// All incoming messages with an envelope Topic matching the
// topic specified will be passed to the given Handler function.
//
// There may be an arbitrary number of handler functions per topic.
//
// Returns a deregister function which needs to be called to
// deregister the handler,
func (p *Pss) Register(topic *Topic, hndlr *handler) func() {
p.handlersMu.Lock()
defer p.handlersMu.Unlock()
handlers := p.handlers[*topic]
if handlers == nil {
handlers = make(map[*handler]bool)
p.handlers[*topic] = handlers
log.Debug("registered handler", "capabilities", hndlr.caps)
}
if hndlr.caps == nil {
hndlr.caps = &handlerCaps{}
}
handlers[hndlr] = true
capabilities, ok := p.getTopicHandlerCaps(*topic)
if !ok {
capabilities = &handlerCaps{}
p.setTopicHandlerCaps(*topic, capabilities)
}
if hndlr.caps.raw {
capabilities.raw = true
}
if hndlr.caps.prox {
capabilities.prox = true
}
return func() { p.deregister(topic, hndlr) }
}
func (p *Pss) deregister(topic *Topic, hndlr *handler) {
p.handlersMu.Lock()
defer p.handlersMu.Unlock()
handlers := p.handlers[*topic]
if len(handlers) > 1 {
delete(p.handlers, *topic)
// topic caps might have changed now that a handler is gone
caps := &handlerCaps{}
for h := range handlers {
if h.caps.raw {
caps.raw = true
}
if h.caps.prox {
caps.prox = true
}
}
p.setTopicHandlerCaps(*topic, caps)
return
}
delete(handlers, hndlr)
}
// Filters incoming messages for processing or forwarding.
// Check if address partially matches
// If yes, it CAN be for us, and we process it
// Only passes error to pss protocol handler if payload is not valid pssmsg
func (p *Pss) handlePssMsg(ctx context.Context, msg interface{}) error {
metrics.GetOrRegisterCounter("pss.handlepssmsg", nil).Inc(1)
pssmsg, ok := msg.(*PssMsg)
if !ok {
return fmt.Errorf("invalid message type. Expected *PssMsg, got %T ", msg)
}
log.Trace("handler", "self", label(p.Kademlia.BaseAddr()), "topic", label(pssmsg.Payload.Topic[:]))
if int64(pssmsg.Expire) < time.Now().Unix() {
metrics.GetOrRegisterCounter("pss.expire", nil).Inc(1)
log.Warn("pss filtered expired message", "from", common.ToHex(p.Kademlia.BaseAddr()), "to", common.ToHex(pssmsg.To))
return nil
}
if p.checkFwdCache(pssmsg) {
log.Trace("pss relay block-cache match (process)", "from", common.ToHex(p.Kademlia.BaseAddr()), "to", (common.ToHex(pssmsg.To)))
return nil
}
p.addFwdCache(pssmsg)
psstopic := Topic(pssmsg.Payload.Topic)
// raw is simplest handler contingency to check, so check that first
var isRaw bool
if pssmsg.isRaw() {
if capabilities, ok := p.getTopicHandlerCaps(psstopic); ok {
if !capabilities.raw {
log.Debug("No handler for raw message", "topic", psstopic)
return nil
}
}
isRaw = true
}
// check if we can be recipient:
// - no prox handler on message and partial address matches
// - prox handler on message and we are in prox regardless of partial address match
// store this result so we don't calculate again on every handler
var isProx bool
if capabilities, ok := p.getTopicHandlerCaps(psstopic); ok {
isProx = capabilities.prox
}
isRecipient := p.isSelfPossibleRecipient(pssmsg, isProx)
if !isRecipient {
log.Trace("pss was for someone else :'( ... forwarding", "pss", common.ToHex(p.BaseAddr()), "prox", isProx)
return p.enqueue(pssmsg)
}
log.Trace("pss for us, yay! ... let's process!", "pss", common.ToHex(p.BaseAddr()), "prox", isProx, "raw", isRaw, "topic", label(pssmsg.Payload.Topic[:]))
if err := p.process(pssmsg, isRaw, isProx); err != nil {
qerr := p.enqueue(pssmsg)
if qerr != nil {
return fmt.Errorf("process fail: processerr %v, queueerr: %v", err, qerr)
}
}
return nil
}
// Entry point to processing a message for which the current node can be the intended recipient.
// Attempts symmetric and asymmetric decryption with stored keys.
// Dispatches message to all handlers matching the message topic
func (p *Pss) process(pssmsg *PssMsg, raw bool, prox bool) error {
metrics.GetOrRegisterCounter("pss.process", nil).Inc(1)
var err error
var recvmsg *whisper.ReceivedMessage
var payload []byte
var from PssAddress
var asymmetric bool
var keyid string
var keyFunc func(envelope *whisper.Envelope) (*whisper.ReceivedMessage, string, PssAddress, error)
envelope := pssmsg.Payload
psstopic := Topic(envelope.Topic)
if raw {
payload = pssmsg.Payload.Data
} else {
if pssmsg.isSym() {
keyFunc = p.processSym
} else {
asymmetric = true
keyFunc = p.processAsym
}
recvmsg, keyid, from, err = keyFunc(envelope)
if err != nil {
return errors.New("Decryption failed")
}
payload = recvmsg.Payload
}
if len(pssmsg.To) < addressLength {
if err := p.enqueue(pssmsg); err != nil {
return err
}
}
p.executeHandlers(psstopic, payload, from, raw, prox, asymmetric, keyid)
return nil
}
// copy all registered handlers for respective topic in order to avoid data race or deadlock
func (p *Pss) getHandlers(topic Topic) (ret []*handler) {
p.handlersMu.RLock()
defer p.handlersMu.RUnlock()
for k := range p.handlers[topic] {
ret = append(ret, k)
}
return ret
}
func (p *Pss) executeHandlers(topic Topic, payload []byte, from PssAddress, raw bool, prox bool, asymmetric bool, keyid string) {
handlers := p.getHandlers(topic)
peer := p2p.NewPeer(enode.ID{}, fmt.Sprintf("%x", from), []p2p.Cap{})
for _, h := range handlers {
if !h.caps.raw && raw {
log.Warn("norawhandler")
continue
}
if !h.caps.prox && prox {
log.Warn("noproxhandler")
continue
}
err := (h.f)(payload, peer, asymmetric, keyid)
if err != nil {
log.Warn("Pss handler failed", "err", err)
}
}
}
// will return false if using partial address
func (p *Pss) isSelfRecipient(msg *PssMsg) bool {
return bytes.Equal(msg.To, p.Kademlia.BaseAddr())
}
// test match of leftmost bytes in given message to node's Kademlia address
func (p *Pss) isSelfPossibleRecipient(msg *PssMsg, prox bool) bool {
local := p.Kademlia.BaseAddr()
// if a partial address matches we are possible recipient regardless of prox
// if not and prox is not set, we are surely not
if bytes.Equal(msg.To, local[:len(msg.To)]) {
return true
} else if !prox {
return false
}
depth := p.Kademlia.NeighbourhoodDepth()
po, _ := network.Pof(p.Kademlia.BaseAddr(), msg.To, 0)
log.Trace("selfpossible", "po", po, "depth", depth)
return depth <= po
}
/////////////////////////////////////////////////////////////////////
// SECTION: Message sending
/////////////////////////////////////////////////////////////////////
func (p *Pss) enqueue(msg *PssMsg) error {
select {
case p.outbox <- msg:
return nil
default:
}
metrics.GetOrRegisterCounter("pss.enqueue.outbox.full", nil).Inc(1)
return errors.New("outbox full")
}
// Send a raw message (any encryption is responsibility of calling client)
//
// Will fail if raw messages are disallowed
func (p *Pss) SendRaw(address PssAddress, topic Topic, msg []byte) error {
if err := validateAddress(address); err != nil {
return err
}
pssMsgParams := &msgParams{
raw: true,
}
payload := &whisper.Envelope{
Data: msg,
Topic: whisper.TopicType(topic),
}
pssMsg := newPssMsg(pssMsgParams)
pssMsg.To = address
pssMsg.Expire = uint32(time.Now().Add(p.msgTTL).Unix())
pssMsg.Payload = payload
p.addFwdCache(pssMsg)
err := p.enqueue(pssMsg)
if err != nil {
return err
}
// if we have a proxhandler on this topic
// also deliver message to ourselves
if capabilities, ok := p.getTopicHandlerCaps(topic); ok {
if p.isSelfPossibleRecipient(pssMsg, true) && capabilities.prox {
return p.process(pssMsg, true, true)
}
}
return nil
}
// Send a message using symmetric encryption
//
// Fails if the key id does not match any of the stored symmetric keys
func (p *Pss) SendSym(symkeyid string, topic Topic, msg []byte) error {
symkey, err := p.GetSymmetricKey(symkeyid)
if err != nil {
return fmt.Errorf("missing valid send symkey %s: %v", symkeyid, err)
}
psp, ok := p.getPeerSym(symkeyid, topic)
if !ok {
return fmt.Errorf("invalid topic '%s' for symkey '%s'", topic.String(), symkeyid)
}
return p.send(psp.address, topic, msg, false, symkey)
}
// Send a message using asymmetric encryption
//
// Fails if the key id does not match any in of the stored public keys
func (p *Pss) SendAsym(pubkeyid string, topic Topic, msg []byte) error {
if _, err := crypto.UnmarshalPubkey(common.FromHex(pubkeyid)); err != nil {
return fmt.Errorf("Cannot unmarshal pubkey: %x", pubkeyid)
}
psp, ok := p.getPeerPub(pubkeyid, topic)
if !ok {
return fmt.Errorf("invalid topic '%s' for pubkey '%s'", topic.String(), pubkeyid)
}
return p.send(psp.address, topic, msg, true, common.FromHex(pubkeyid))
}
// Send is payload agnostic, and will accept any byte slice as payload
// It generates an whisper envelope for the specified recipient and topic,
// and wraps the message payload in it.
// TODO: Implement proper message padding
func (p *Pss) send(to []byte, topic Topic, msg []byte, asymmetric bool, key []byte) error {
metrics.GetOrRegisterCounter("pss.send", nil).Inc(1)
if key == nil || bytes.Equal(key, []byte{}) {
return fmt.Errorf("Zero length key passed to pss send")
}
padding := make([]byte, p.paddingByteSize)
c, err := rand.Read(padding)
if err != nil {
return err
} else if c < p.paddingByteSize {
return fmt.Errorf("invalid padding length: %d", c)
}
wparams := &whisper.MessageParams{
TTL: defaultWhisperTTL,
Src: p.privateKey,
Topic: whisper.TopicType(topic),
WorkTime: defaultWhisperWorkTime,
PoW: defaultWhisperPoW,
Payload: msg,
Padding: padding,
}
if asymmetric {
pk, err := crypto.UnmarshalPubkey(key)
if err != nil {
return fmt.Errorf("Cannot unmarshal pubkey: %x", key)
}
wparams.Dst = pk
} else {
wparams.KeySym = key
}
// set up outgoing message container, which does encryption and envelope wrapping
woutmsg, err := whisper.NewSentMessage(wparams)
if err != nil {
return fmt.Errorf("failed to generate whisper message encapsulation: %v", err)
}
// performs encryption.
// Does NOT perform / performs negligible PoW due to very low difficulty setting
// after this the message is ready for sending
envelope, err := woutmsg.Wrap(wparams)
if err != nil {
return fmt.Errorf("failed to perform whisper encryption: %v", err)
}
log.Trace("pssmsg whisper done", "env", envelope, "wparams payload", common.ToHex(wparams.Payload), "to", common.ToHex(to), "asym", asymmetric, "key", common.ToHex(key))
// prepare for devp2p transport
pssMsgParams := &msgParams{
sym: !asymmetric,
}
pssMsg := newPssMsg(pssMsgParams)
pssMsg.To = to
pssMsg.Expire = uint32(time.Now().Add(p.msgTTL).Unix())
pssMsg.Payload = envelope
err = p.enqueue(pssMsg)
if err != nil {
return err
}
if capabilities, ok := p.getTopicHandlerCaps(topic); ok {
if p.isSelfPossibleRecipient(pssMsg, true) && capabilities.prox {
return p.process(pssMsg, true, true)
}
}
return nil
}
// sendFunc is a helper function that tries to send a message and returns true on success.
// It is set here for usage in production, and optionally overridden in tests.
var sendFunc = sendMsg
// tries to send a message, returns true if successful
func sendMsg(p *Pss, sp *network.Peer, msg *PssMsg) bool {
var isPssEnabled bool
info := sp.Info()
for _, capability := range info.Caps {
if capability == p.capstring {
isPssEnabled = true
break
}
}
if !isPssEnabled {
log.Error("peer doesn't have matching pss capabilities, skipping", "peer", info.Name, "caps", info.Caps)
return false
}
// get the protocol peer from the forwarding peer cache
p.fwdPoolMu.RLock()
pp := p.fwdPool[sp.Info().ID]
p.fwdPoolMu.RUnlock()
err := pp.Send(context.TODO(), msg)
if err != nil {
metrics.GetOrRegisterCounter("pss.pp.send.error", nil).Inc(1)
log.Error(err.Error())
}
return err == nil
}
// Forwards a pss message to the peer(s) based on recipient address according to the algorithm
// described below. The recipient address can be of any length, and the byte slice will be matched
// to the MSB slice of the peer address of the equivalent length.
//
// If the recipient address (or partial address) is within the neighbourhood depth of the forwarding
// node, then it will be forwarded to all the nearest neighbours of the forwarding node. In case of
// partial address, it should be forwarded to all the peers matching the partial address, if there
// are any; otherwise only to one peer, closest to the recipient address. In any case, if the message
// forwarding fails, the node should try to forward it to the next best peer, until the message is
// successfully forwarded to at least one peer.
func (p *Pss) forward(msg *PssMsg) error {
metrics.GetOrRegisterCounter("pss.forward", nil).Inc(1)
sent := 0 // number of successful sends
to := make([]byte, addressLength)
copy(to[:len(msg.To)], msg.To)
neighbourhoodDepth := p.Kademlia.NeighbourhoodDepth()
// luminosity is the opposite of darkness. the more bytes are removed from the address, the higher is darkness,
// but the luminosity is less. here luminosity equals the number of bits given in the destination address.
luminosityRadius := len(msg.To) * 8
// proximity order function matching up to neighbourhoodDepth bits (po <= neighbourhoodDepth)
pof := pot.DefaultPof(neighbourhoodDepth)
// soft threshold for msg broadcast
broadcastThreshold, _ := pof(to, p.BaseAddr(), 0)
if broadcastThreshold > luminosityRadius {
broadcastThreshold = luminosityRadius
}
var onlySendOnce bool // indicates if the message should only be sent to one peer with closest address
// if measured from the recipient address as opposed to the base address (see Kademlia.EachConn
// call below), then peers that fall in the same proximity bin as recipient address will appear
// [at least] one bit closer, but only if these additional bits are given in the recipient address.
if broadcastThreshold < luminosityRadius && broadcastThreshold < neighbourhoodDepth {
broadcastThreshold++
onlySendOnce = true
}
p.Kademlia.EachConn(to, addressLength*8, func(sp *network.Peer, po int) bool {
if po < broadcastThreshold && sent > 0 {
return false // stop iterating
}
if sendFunc(p, sp, msg) {
sent++
if onlySendOnce {
return false
}
if po == addressLength*8 {
// stop iterating if successfully sent to the exact recipient (perfect match of full address)
return false
}
}
return true
})
// if we failed to send to anyone, re-insert message in the send-queue
if sent == 0 {
log.Debug("unable to forward to any peers")
if err := p.enqueue(msg); err != nil {
metrics.GetOrRegisterCounter("pss.forward.enqueue.error", nil).Inc(1)
log.Error(err.Error())
return err
}
}
// cache the message
p.addFwdCache(msg)
return nil
}
/////////////////////////////////////////////////////////////////////
// SECTION: Caching
/////////////////////////////////////////////////////////////////////
// cleanFwdCache is used to periodically remove expired entries from the forward cache
func (p *Pss) cleanFwdCache() {
metrics.GetOrRegisterCounter("pss.cleanfwdcache", nil).Inc(1)
p.fwdCacheMu.Lock()
defer p.fwdCacheMu.Unlock()
for k, v := range p.fwdCache {
if v.expiresAt.Before(time.Now()) {
delete(p.fwdCache, k)
}
}
}
func label(b []byte) string {
return fmt.Sprintf("%04x", b[:2])
}
// add a message to the cache
func (p *Pss) addFwdCache(msg *PssMsg) error {
metrics.GetOrRegisterCounter("pss.addfwdcache", nil).Inc(1)
var entry pssCacheEntry
var ok bool
p.fwdCacheMu.Lock()
defer p.fwdCacheMu.Unlock()
digest := p.digest(msg)
if entry, ok = p.fwdCache[digest]; !ok {
entry = pssCacheEntry{}
}
entry.expiresAt = time.Now().Add(p.cacheTTL)
p.fwdCache[digest] = entry
return nil
}
// check if message is in the cache
func (p *Pss) checkFwdCache(msg *PssMsg) bool {
p.fwdCacheMu.Lock()
defer p.fwdCacheMu.Unlock()
digest := p.digest(msg)
entry, ok := p.fwdCache[digest]
if ok {
if entry.expiresAt.After(time.Now()) {
log.Trace("unexpired cache", "digest", fmt.Sprintf("%x", digest))
metrics.GetOrRegisterCounter("pss.checkfwdcache.unexpired", nil).Inc(1)
return true
}
metrics.GetOrRegisterCounter("pss.checkfwdcache.expired", nil).Inc(1)
}
return false
}
// Digest of message
func (p *Pss) digest(msg *PssMsg) pssDigest {
return p.digestBytes(msg.serialize())
}
func (p *Pss) digestBytes(msg []byte) pssDigest {
hasher := p.hashPool.Get().(hash.Hash)
defer p.hashPool.Put(hasher)
hasher.Reset()
hasher.Write(msg)
digest := pssDigest{}
key := hasher.Sum(nil)
copy(digest[:], key[:digestLength])
return digest
}
func validateAddress(addr PssAddress) error {
if len(addr) > addressLength {
return errors.New("address too long")
}
return nil
}
|