aboutsummaryrefslogtreecommitdiffstats
path: root/peer.go
blob: 41d3ef13f7feccc4c232e4cfe31cf65c5478812a (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
package main

import (
	"encoding/base64"
	"errors"
	"fmt"
	"sync"
	"time"
)

const (
	PeerRoutineNumber = 4
	EventInterval     = time.Millisecond
)

type Peer struct {
	isRunning                   AtomicBool
	mutex                       sync.RWMutex
	keyPairs                    KeyPairs
	handshake                   Handshake
	device                      *Device
	endpoint                    Endpoint
	persistentKeepaliveInterval uint16
	_                           uint32 // padding for alignment

	stats struct {
		txBytes           uint64 // bytes send to peer (endpoint)
		rxBytes           uint64 // bytes received from peer
		lastHandshakeNano int64  // nano seconds since epoch
	}

	time struct {
		mutex         sync.RWMutex
		lastSend      time.Time // last send message
		lastHandshake time.Time // last completed handshake
		nextKeepalive time.Time
	}

	event struct {
		dataSent                        *Event
		dataReceived                    *Event
		anyAuthenticatedPacketReceived  *Event
		anyAuthenticatedPacketTraversal *Event
		handshakeComplete               *Event
		handshakePushDeadline           *Event
		ephemeralKeyCreated             *Event
	}

	signal struct {
		newKeyPair         Signal // size 1, new key pair was generated
		handshakeCompleted Signal // size 1, handshake completed
		handshakeBegin     Signal // size 1, begin new handshake begin
		messageSend        Signal // size 1, message was send to peer
		messageReceived    Signal // size 1, authenticated message recv

		flushNonceQueue chan struct{} // size 0, empty queued packets
	}

	timer struct {
		sendLastMinuteHandshake AtomicBool
		needAnotherKeepalive    AtomicBool
	}

	queue struct {
		nonce    chan *QueueOutboundElement // nonce / pre-handshake queue
		outbound chan *QueueOutboundElement // sequential ordering of work
		inbound  chan *QueueInboundElement  // sequential ordering of work
	}

	routines struct {
		mutex    sync.Mutex     // held when stopping / starting routines
		starting sync.WaitGroup // routines pending start
		stopping sync.WaitGroup // routines pending stop
		stop     Signal         // size 0, stop all go-routines in peer
	}

	mac CookieGenerator
}

func (device *Device) NewPeer(pk NoisePublicKey) (*Peer, error) {

	if device.isClosed.Get() {
		return nil, errors.New("Device closed")
	}

	// lock resources

	device.state.mutex.Lock()
	defer device.state.mutex.Unlock()

	device.noise.mutex.RLock()
	defer device.noise.mutex.RUnlock()

	device.peers.mutex.Lock()
	defer device.peers.mutex.Unlock()

	// check if over limit

	if len(device.peers.keyMap) >= MaxPeers {
		return nil, errors.New("Too many peers")
	}

	// create peer

	peer := new(Peer)
	peer.mutex.Lock()
	defer peer.mutex.Unlock()

	peer.mac.Init(pk)
	peer.device = device
	peer.isRunning.Set(false)

	// map public key

	_, ok := device.peers.keyMap[pk]
	if ok {
		return nil, errors.New("Adding existing peer")
	}
	device.peers.keyMap[pk] = peer

	// pre-compute DH

	handshake := &peer.handshake
	handshake.mutex.Lock()
	handshake.remoteStatic = pk
	handshake.precomputedStaticStatic = device.noise.privateKey.sharedSecret(pk)
	handshake.mutex.Unlock()

	// reset endpoint

	peer.endpoint = nil

	// prepare signaling & routines

	peer.routines.mutex.Lock()
	peer.routines.stop = NewSignal()
	peer.routines.mutex.Unlock()

	// start peer

	if peer.device.isUp.Get() {
		peer.Start()
	}

	return peer, nil
}

func (peer *Peer) SendBuffer(buffer []byte) error {
	peer.device.net.mutex.RLock()
	defer peer.device.net.mutex.RUnlock()

	if peer.device.net.bind == nil {
		return errors.New("No bind")
	}

	peer.mutex.RLock()
	defer peer.mutex.RUnlock()

	if peer.endpoint == nil {
		return errors.New("No known endpoint for peer")
	}

	return peer.device.net.bind.Send(buffer, peer.endpoint)
}

/* Returns a short string identifier for logging
 */
func (peer *Peer) String() string {
	return fmt.Sprintf(
		"peer(%s)",
		base64.StdEncoding.EncodeToString(peer.handshake.remoteStatic[:]),
	)
}

func (peer *Peer) Start() {

	// should never start a peer on a closed device

	if peer.device.isClosed.Get() {
		return
	}

	// prevent simultaneous start/stop operations

	peer.routines.mutex.Lock()
	defer peer.routines.mutex.Unlock()

	if peer.isRunning.Get() {
		return
	}

	device := peer.device
	device.log.Debug.Println(peer, ": Starting...")

	// sanity check : these should be 0

	peer.routines.starting.Wait()
	peer.routines.stopping.Wait()

	// events

	peer.event.dataSent = newEvent(EventInterval)
	peer.event.dataReceived = newEvent(EventInterval)
	peer.event.anyAuthenticatedPacketReceived = newEvent(EventInterval)
	peer.event.anyAuthenticatedPacketTraversal = newEvent(EventInterval)
	peer.event.handshakeComplete = newEvent(EventInterval)
	peer.event.handshakePushDeadline = newEvent(EventInterval)
	peer.event.ephemeralKeyCreated = newEvent(EventInterval)

	// prepare queues and signals

	peer.signal.newKeyPair = NewSignal()
	peer.signal.handshakeBegin = NewSignal()
	peer.signal.handshakeCompleted = NewSignal()

	peer.signal.flushNonceQueue = make(chan struct{})

	peer.queue.nonce = make(chan *QueueOutboundElement, QueueOutboundSize)
	peer.queue.outbound = make(chan *QueueOutboundElement, QueueOutboundSize)
	peer.queue.inbound = make(chan *QueueInboundElement, QueueInboundSize)

	peer.routines.stop = NewSignal()
	peer.isRunning.Set(true)

	// wait for routines to start

	peer.routines.starting.Add(PeerRoutineNumber)
	peer.routines.stopping.Add(PeerRoutineNumber)

	go peer.RoutineNonce()
	go peer.RoutineTimerHandler()
	go peer.RoutineSequentialSender()
	go peer.RoutineSequentialReceiver()

	peer.routines.starting.Wait()
	peer.isRunning.Set(true)
}

func (peer *Peer) Stop() {

	// prevent simultaneous start/stop operations

	peer.routines.mutex.Lock()
	defer peer.routines.mutex.Unlock()

	if !peer.isRunning.Swap(false) {
		return
	}

	device := peer.device
	device.log.Debug.Println(peer, ": Stopping...")

	// stop & wait for ongoing peer routines

	peer.routines.starting.Wait()
	peer.routines.stop.Broadcast()
	peer.routines.stopping.Wait()

	// close queues

	close(peer.queue.nonce)
	close(peer.queue.outbound)
	close(peer.queue.inbound)

	// close signals

	peer.signal.newKeyPair.Close()
	peer.signal.handshakeBegin.Close()
	peer.signal.handshakeCompleted.Close()

	close(peer.signal.flushNonceQueue)

	peer.signal.flushNonceQueue = nil

	// clear key pairs

	kp := &peer.keyPairs
	kp.mutex.Lock()

	device.DeleteKeyPair(kp.previous)
	device.DeleteKeyPair(kp.current)
	device.DeleteKeyPair(kp.next)

	kp.previous = nil
	kp.current = nil
	kp.next = nil
	kp.mutex.Unlock()

	// clear handshake state

	hs := &peer.handshake
	hs.mutex.Lock()
	device.indices.Delete(hs.localIndex)
	hs.Clear()
	hs.mutex.Unlock()
}