aboutsummaryrefslogtreecommitdiffstats
path: root/whisper/whisperv6/peer.go
blob: 4f9a7c3780bda0ee4e8b95674a070162afbf1b1c (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
// Copyright 2016 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 whisperv6

import (
    "fmt"
    "math"
    "time"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/log"
    "github.com/ethereum/go-ethereum/p2p"
    "github.com/ethereum/go-ethereum/rlp"
    set "gopkg.in/fatih/set.v0"
)

// Peer represents a whisper protocol peer connection.
type Peer struct {
    host *Whisper
    peer *p2p.Peer
    ws   p2p.MsgReadWriter

    trusted        bool
    powRequirement float64
    bloomFilter    []byte // may contain nil in case of full node

    known *set.Set // Messages already known by the peer to avoid wasting bandwidth

    quit chan struct{}
}

// newPeer creates a new whisper peer object, but does not run the handshake itself.
func newPeer(host *Whisper, remote *p2p.Peer, rw p2p.MsgReadWriter) *Peer {
    return &Peer{
        host:           host,
        peer:           remote,
        ws:             rw,
        trusted:        false,
        powRequirement: 0.0,
        known:          set.New(),
        quit:           make(chan struct{}),
    }
}

// start initiates the peer updater, periodically broadcasting the whisper packets
// into the network.
func (peer *Peer) start() {
    go peer.update()
    log.Trace("start", "peer", peer.ID())
}

// stop terminates the peer updater, stopping message forwarding to it.
func (peer *Peer) stop() {
    close(peer.quit)
    log.Trace("stop", "peer", peer.ID())
}

// handshake sends the protocol initiation status message to the remote peer and
// verifies the remote status too.
func (peer *Peer) handshake() error {
    // Send the handshake status message asynchronously
    errc := make(chan error, 1)
    go func() {
        pow := peer.host.MinPow()
        powConverted := math.Float64bits(pow)
        bloom := peer.host.BloomFilter()
        errc <- p2p.SendItems(peer.ws, statusCode, ProtocolVersion, powConverted, bloom)
    }()

    // Fetch the remote status packet and verify protocol match
    packet, err := peer.ws.ReadMsg()
    if err != nil {
        return err
    }
    if packet.Code != statusCode {
        return fmt.Errorf("peer [%x] sent packet %x before status packet", peer.ID(), packet.Code)
    }
    s := rlp.NewStream(packet.Payload, uint64(packet.Size))
    _, err = s.List()
    if err != nil {
        return fmt.Errorf("peer [%x] sent bad status message: %v", peer.ID(), err)
    }
    peerVersion, err := s.Uint()
    if err != nil {
        return fmt.Errorf("peer [%x] sent bad status message (unable to decode version): %v", peer.ID(), err)
    }
    if peerVersion != ProtocolVersion {
        return fmt.Errorf("peer [%x]: protocol version mismatch %d != %d", peer.ID(), peerVersion, ProtocolVersion)
    }

    // only version is mandatory, subsequent parameters are optional
    powRaw, err := s.Uint()
    if err == nil {
        pow := math.Float64frombits(powRaw)
        if math.IsInf(pow, 0) || math.IsNaN(pow) || pow < 0.0 {
            return fmt.Errorf("peer [%x] sent bad status message: invalid pow", peer.ID())
        }
        peer.powRequirement = pow

        var bloom []byte
        err = s.Decode(&bloom)
        if err == nil {
            sz := len(bloom)
            if sz != bloomFilterSize && sz != 0 {
                return fmt.Errorf("peer [%x] sent bad status message: wrong bloom filter size %d", peer.ID(), sz)
            }
            if isFullNode(bloom) {
                peer.bloomFilter = nil
            } else {
                peer.bloomFilter = bloom
            }
        }
    }

    if err := <-errc; err != nil {
        return fmt.Errorf("peer [%x] failed to send status packet: %v", peer.ID(), err)
    }
    return nil
}

// update executes periodic operations on the peer, including message transmission
// and expiration.
func (peer *Peer) update() {
    // Start the tickers for the updates
    expire := time.NewTicker(expirationCycle)
    transmit := time.NewTicker(transmissionCycle)

    // Loop and transmit until termination is requested
    for {
        select {
        case <-expire.C:
            peer.expire()

        case <-transmit.C:
            if err := peer.broadcast(); err != nil {
                log.Trace("broadcast failed", "reason", err, "peer", peer.ID())
                return
            }

        case <-peer.quit:
            return
        }
    }
}

// mark marks an envelope known to the peer so that it won't be sent back.
func (peer *Peer) mark(envelope *Envelope) {
    peer.known.Add(envelope.Hash())
}

// marked checks if an envelope is already known to the remote peer.
func (peer *Peer) marked(envelope *Envelope) bool {
    return peer.known.Has(envelope.Hash())
}

// expire iterates over all the known envelopes in the host and removes all
// expired (unknown) ones from the known list.
func (peer *Peer) expire() {
    unmark := make(map[common.Hash]struct{})
    peer.known.Each(func(v interface{}) bool {
        if !peer.host.isEnvelopeCached(v.(common.Hash)) {
            unmark[v.(common.Hash)] = struct{}{}
        }
        return true
    })
    // Dump all known but no longer cached
    for hash := range unmark {
        peer.known.Remove(hash)
    }
}

// broadcast iterates over the collection of envelopes and transmits yet unknown
// ones over the network.
func (peer *Peer) broadcast() error {
    envelopes := peer.host.Envelopes()
    bundle := make([]*Envelope, 0, len(envelopes))
    for _, envelope := range envelopes {
        if !peer.marked(envelope) && envelope.PoW() >= peer.powRequirement && peer.bloomMatch(envelope) {
            bundle = append(bundle, envelope)
        }
    }

    if len(bundle) > 0 {
        // transmit the batch of envelopes
        if err := p2p.Send(peer.ws, messagesCode, bundle); err != nil {
            return err
        }

        // mark envelopes only if they were successfully sent
        for _, e := range bundle {
            peer.mark(e)
        }

        log.Trace("broadcast", "num. messages", len(bundle))
    }
    return nil
}

// ID returns a peer's id
func (peer *Peer) ID() []byte {
    id := peer.peer.ID()
    return id[:]
}

func (peer *Peer) notifyAboutPowRequirementChange(pow float64) error {
    i := math.Float64bits(pow)
    return p2p.Send(peer.ws, powRequirementCode, i)
}

func (peer *Peer) notifyAboutBloomFilterChange(bloom []byte) error {
    return p2p.Send(peer.ws, bloomFilterExCode, bloom)
}

func (peer *Peer) bloomMatch(env *Envelope) bool {
    if peer.bloomFilter == nil {
        // no filter - full node, accepts all envelops
        return true
    }

    return bloomFilterMatch(peer.bloomFilter, env.Bloom())
}