aboutsummaryrefslogtreecommitdiff
path: root/vendor/github.com/bwmarrin/discordgo/voice.go
blob: aedb87904886699553668b475a467a265a590e22 (plain)
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
// Discordgo - Discord bindings for Go
// Available at https://github.com/bwmarrin/discordgo

// Copyright 2015-2016 Bruce Marriner <bruce@sqls.net>.  All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// This file contains code related to Discord voice suppport

package discordgo

import (
	"encoding/binary"
	"encoding/json"
	"fmt"
	"net"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/gorilla/websocket"
	"golang.org/x/crypto/nacl/secretbox"
)

// ------------------------------------------------------------------------------------------------
// Code related to both VoiceConnection Websocket and UDP connections.
// ------------------------------------------------------------------------------------------------

// A VoiceConnection struct holds all the data and functions related to a Discord Voice Connection.
type VoiceConnection struct {
	sync.RWMutex

	Debug        bool // If true, print extra logging -- DEPRECATED
	LogLevel     int
	Ready        bool // If true, voice is ready to send/receive audio
	UserID       string
	GuildID      string
	ChannelID    string
	deaf         bool
	mute         bool
	speaking     bool
	reconnecting bool // If true, voice connection is trying to reconnect

	OpusSend chan []byte  // Chan for sending opus audio
	OpusRecv chan *Packet // Chan for receiving opus audio

	wsConn  *websocket.Conn
	wsMutex sync.Mutex
	udpConn *net.UDPConn
	session *Session

	sessionID string
	token     string
	endpoint  string

	// Used to send a close signal to goroutines
	close chan struct{}

	// Used to allow blocking until connected
	connected chan bool

	// Used to pass the sessionid from onVoiceStateUpdate
	// sessionRecv chan string UNUSED ATM

	op4 voiceOP4
	op2 voiceOP2

	voiceSpeakingUpdateHandlers []VoiceSpeakingUpdateHandler
}

// VoiceSpeakingUpdateHandler type provides a function definition for the
// VoiceSpeakingUpdate event
type VoiceSpeakingUpdateHandler func(vc *VoiceConnection, vs *VoiceSpeakingUpdate)

// Speaking sends a speaking notification to Discord over the voice websocket.
// This must be sent as true prior to sending audio and should be set to false
// once finished sending audio.
//  b  : Send true if speaking, false if not.
func (v *VoiceConnection) Speaking(b bool) (err error) {

	v.log(LogDebug, "called (%t)", b)

	type voiceSpeakingData struct {
		Speaking bool `json:"speaking"`
		Delay    int  `json:"delay"`
	}

	type voiceSpeakingOp struct {
		Op   int               `json:"op"` // Always 5
		Data voiceSpeakingData `json:"d"`
	}

	if v.wsConn == nil {
		return fmt.Errorf("no VoiceConnection websocket")
	}

	data := voiceSpeakingOp{5, voiceSpeakingData{b, 0}}
	v.wsMutex.Lock()
	err = v.wsConn.WriteJSON(data)
	v.wsMutex.Unlock()

	v.Lock()
	defer v.Unlock()
	if err != nil {
		v.speaking = false
		v.log(LogError, "Speaking() write json error, %s", err)
		return
	}

	v.speaking = b

	return
}

// ChangeChannel sends Discord a request to change channels within a Guild
// !!! NOTE !!! This function may be removed in favour of just using ChannelVoiceJoin
func (v *VoiceConnection) ChangeChannel(channelID string, mute, deaf bool) (err error) {

	v.log(LogInformational, "called")

	data := voiceChannelJoinOp{4, voiceChannelJoinData{&v.GuildID, &channelID, mute, deaf}}
	v.wsMutex.Lock()
	err = v.session.wsConn.WriteJSON(data)
	v.wsMutex.Unlock()
	if err != nil {
		return
	}
	v.ChannelID = channelID
	v.deaf = deaf
	v.mute = mute
	v.speaking = false

	return
}

// Disconnect disconnects from this voice channel and closes the websocket
// and udp connections to Discord.
func (v *VoiceConnection) Disconnect() (err error) {

	// Send a OP4 with a nil channel to disconnect
	v.Lock()
	if v.sessionID != "" {
		data := voiceChannelJoinOp{4, voiceChannelJoinData{&v.GuildID, nil, true, true}}
		v.session.wsMutex.Lock()
		err = v.session.wsConn.WriteJSON(data)
		v.session.wsMutex.Unlock()
		v.sessionID = ""
	}
	v.Unlock()

	// Close websocket and udp connections
	v.Close()

	v.log(LogInformational, "Deleting VoiceConnection %s", v.GuildID)

	v.session.Lock()
	delete(v.session.VoiceConnections, v.GuildID)
	v.session.Unlock()

	return
}

// Close closes the voice ws and udp connections
func (v *VoiceConnection) Close() {

	v.log(LogInformational, "called")

	v.Lock()
	defer v.Unlock()

	v.Ready = false
	v.speaking = false

	if v.close != nil {
		v.log(LogInformational, "closing v.close")
		close(v.close)
		v.close = nil
	}

	if v.udpConn != nil {
		v.log(LogInformational, "closing udp")
		err := v.udpConn.Close()
		if err != nil {
			v.log(LogError, "error closing udp connection, %s", err)
		}
		v.udpConn = nil
	}

	if v.wsConn != nil {
		v.log(LogInformational, "sending close frame")

		// To cleanly close a connection, a client should send a close
		// frame and wait for the server to close the connection.
		v.wsMutex.Lock()
		err := v.wsConn.WriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseNormalClosure, ""))
		v.wsMutex.Unlock()
		if err != nil {
			v.log(LogError, "error closing websocket, %s", err)
		}

		// TODO: Wait for Discord to actually close the connection.
		time.Sleep(1 * time.Second)

		v.log(LogInformational, "closing websocket")
		err = v.wsConn.Close()
		if err != nil {
			v.log(LogError, "error closing websocket, %s", err)
		}

		v.wsConn = nil
	}
}

// AddHandler adds a Handler for VoiceSpeakingUpdate events.
func (v *VoiceConnection) AddHandler(h VoiceSpeakingUpdateHandler) {
	v.Lock()
	defer v.Unlock()

	v.voiceSpeakingUpdateHandlers = append(v.voiceSpeakingUpdateHandlers, h)
}

// VoiceSpeakingUpdate is a struct for a VoiceSpeakingUpdate event.
type VoiceSpeakingUpdate struct {
	UserID   string `json:"user_id"`
	SSRC     int    `json:"ssrc"`
	Speaking bool   `json:"speaking"`
}

// ------------------------------------------------------------------------------------------------
// Unexported Internal Functions Below.
// ------------------------------------------------------------------------------------------------

// A voiceOP4 stores the data for the voice operation 4 websocket event
// which provides us with the NaCl SecretBox encryption key
type voiceOP4 struct {
	SecretKey [32]byte `json:"secret_key"`
	Mode      string   `json:"mode"`
}

// A voiceOP2 stores the data for the voice operation 2 websocket event
// which is sort of like the voice READY packet
type voiceOP2 struct {
	SSRC              uint32        `json:"ssrc"`
	Port              int           `json:"port"`
	Modes             []string      `json:"modes"`
	HeartbeatInterval time.Duration `json:"heartbeat_interval"`
	IP                string        `json:"ip"`
}

// WaitUntilConnected waits for the Voice Connection to
// become ready, if it does not become ready it returns an err
func (v *VoiceConnection) waitUntilConnected() error {

	v.log(LogInformational, "called")

	i := 0
	for {
		v.RLock()
		ready := v.Ready
		v.RUnlock()
		if ready {
			return nil
		}

		if i > 10 {
			return fmt.Errorf("timeout waiting for voice")
		}

		time.Sleep(1 * time.Second)
		i++
	}
}

// Open opens a voice connection.  This should be called
// after VoiceChannelJoin is used and the data VOICE websocket events
// are captured.
func (v *VoiceConnection) open() (err error) {

	v.log(LogInformational, "called")

	v.Lock()
	defer v.Unlock()

	// Don't open a websocket if one is already open
	if v.wsConn != nil {
		v.log(LogWarning, "refusing to overwrite non-nil websocket")
		return
	}

	// TODO temp? loop to wait for the SessionID
	i := 0
	for {
		if v.sessionID != "" {
			break
		}
		if i > 20 { // only loop for up to 1 second total
			return fmt.Errorf("did not receive voice Session ID in time")
		}
		time.Sleep(50 * time.Millisecond)
		i++
	}

	// Connect to VoiceConnection Websocket
	vg := "wss://" + strings.TrimSuffix(v.endpoint, ":80")
	v.log(LogInformational, "connecting to voice endpoint %s", vg)
	v.wsConn, _, err = websocket.DefaultDialer.Dial(vg, nil)
	if err != nil {
		v.log(LogWarning, "error connecting to voice endpoint %s, %s", vg, err)
		v.log(LogDebug, "voice struct: %#v\n", v)
		return
	}

	type voiceHandshakeData struct {
		ServerID  string `json:"server_id"`
		UserID    string `json:"user_id"`
		SessionID string `json:"session_id"`
		Token     string `json:"token"`
	}
	type voiceHandshakeOp struct {
		Op   int                `json:"op"` // Always 0
		Data voiceHandshakeData `json:"d"`
	}
	data := voiceHandshakeOp{0, voiceHandshakeData{v.GuildID, v.UserID, v.sessionID, v.token}}

	err = v.wsConn.WriteJSON(data)
	if err != nil {
		v.log(LogWarning, "error sending init packet, %s", err)
		return
	}

	v.close = make(chan struct{})
	go v.wsListen(v.wsConn, v.close)

	// add loop/check for Ready bool here?
	// then return false if not ready?
	// but then wsListen will also err.

	return
}

// wsListen listens on the voice websocket for messages and passes them
// to the voice event handler.  This is automatically called by the Open func
func (v *VoiceConnection) wsListen(wsConn *websocket.Conn, close <-chan struct{}) {

	v.log(LogInformational, "called")

	for {
		_, message, err := v.wsConn.ReadMessage()
		if err != nil {
			// 4014 indicates a manual disconnection by someone in the guild;
			// we shouldn't reconnect.
			if websocket.IsCloseError(err, 4014) {
				v.log(LogInformational, "received 4014 manual disconnection")

				// Abandon the voice WS connection
				v.Lock()
				v.wsConn = nil
				v.Unlock()

				v.session.Lock()
				delete(v.session.VoiceConnections, v.GuildID)
				v.session.Unlock()

				v.Close()

				return
			}

			// Detect if we have been closed manually. If a Close() has already
			// happened, the websocket we are listening on will be different to the
			// current session.
			v.RLock()
			sameConnection := v.wsConn == wsConn
			v.RUnlock()
			if sameConnection {

				v.log(LogError, "voice endpoint %s websocket closed unexpectantly, %s", v.endpoint, err)

				// Start reconnect goroutine then exit.
				go v.reconnect()
			}
			return
		}

		// Pass received message to voice event handler
		select {
		case <-close:
			return
		default:
			go v.onEvent(message)
		}
	}
}

// wsEvent handles any voice websocket events. This is only called by the
// wsListen() function.
func (v *VoiceConnection) onEvent(message []byte) {

	v.log(LogDebug, "received: %s", string(message))

	var e Event
	if err := json.Unmarshal(message, &e); err != nil {
		v.log(LogError, "unmarshall error, %s", err)
		return
	}

	switch e.Operation {

	case 2: // READY

		if err := json.Unmarshal(e.RawData, &v.op2); err != nil {
			v.log(LogError, "OP2 unmarshall error, %s, %s", err, string(e.RawData))
			return
		}

		// Start the voice websocket heartbeat to keep the connection alive
		go v.wsHeartbeat(v.wsConn, v.close, v.op2.HeartbeatInterval)
		// TODO monitor a chan/bool to verify this was successful

		// Start the UDP connection
		err := v.udpOpen()
		if err != nil {
			v.log(LogError, "error opening udp connection, %s", err)
			return
		}

		// Start the opusSender.
		// TODO: Should we allow 48000/960 values to be user defined?
		if v.OpusSend == nil {
			v.OpusSend = make(chan []byte, 2)
		}
		go v.opusSender(v.udpConn, v.close, v.OpusSend, 48000, 960)

		// Start the opusReceiver
		if !v.deaf {
			if v.OpusRecv == nil {
				v.OpusRecv = make(chan *Packet, 2)
			}

			go v.opusReceiver(v.udpConn, v.close, v.OpusRecv)
		}

		return

	case 3: // HEARTBEAT response
		// add code to use this to track latency?
		return

	case 4: // udp encryption secret key
		v.Lock()
		defer v.Unlock()

		v.op4 = voiceOP4{}
		if err := json.Unmarshal(e.RawData, &v.op4); err != nil {
			v.log(LogError, "OP4 unmarshall error, %s, %s", err, string(e.RawData))
			return
		}
		return

	case 5:
		if len(v.voiceSpeakingUpdateHandlers) == 0 {
			return
		}

		voiceSpeakingUpdate := &VoiceSpeakingUpdate{}
		if err := json.Unmarshal(e.RawData, voiceSpeakingUpdate); err != nil {
			v.log(LogError, "OP5 unmarshall error, %s, %s", err, string(e.RawData))
			return
		}

		for _, h := range v.voiceSpeakingUpdateHandlers {
			h(v, voiceSpeakingUpdate)
		}

	default:
		v.log(LogDebug, "unknown voice operation, %d, %s", e.Operation, string(e.RawData))
	}

	return
}

type voiceHeartbeatOp struct {
	Op   int `json:"op"` // Always 3
	Data int `json:"d"`
}

// NOTE :: When a guild voice server changes how do we shut this down
// properly, so a new connection can be setup without fuss?
//
// wsHeartbeat sends regular heartbeats to voice Discord so it knows the client
// is still connected.  If you do not send these heartbeats Discord will
// disconnect the websocket connection after a few seconds.
func (v *VoiceConnection) wsHeartbeat(wsConn *websocket.Conn, close <-chan struct{}, i time.Duration) {

	if close == nil || wsConn == nil {
		return
	}

	var err error
	ticker := time.NewTicker(i * time.Millisecond)
	defer ticker.Stop()
	for {
		v.log(LogDebug, "sending heartbeat packet")
		v.wsMutex.Lock()
		err = wsConn.WriteJSON(voiceHeartbeatOp{3, int(time.Now().Unix())})
		v.wsMutex.Unlock()
		if err != nil {
			v.log(LogError, "error sending heartbeat to voice endpoint %s, %s", v.endpoint, err)
			return
		}

		select {
		case <-ticker.C:
			// continue loop and send heartbeat
		case <-close:
			return
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Code related to the VoiceConnection UDP connection
// ------------------------------------------------------------------------------------------------

type voiceUDPData struct {
	Address string `json:"address"` // Public IP of machine running this code
	Port    uint16 `json:"port"`    // UDP Port of machine running this code
	Mode    string `json:"mode"`    // always "xsalsa20_poly1305"
}

type voiceUDPD struct {
	Protocol string       `json:"protocol"` // Always "udp" ?
	Data     voiceUDPData `json:"data"`
}

type voiceUDPOp struct {
	Op   int       `json:"op"` // Always 1
	Data voiceUDPD `json:"d"`
}

// udpOpen opens a UDP connection to the voice server and completes the
// initial required handshake.  This connection is left open in the session
// and can be used to send or receive audio.  This should only be called
// from voice.wsEvent OP2
func (v *VoiceConnection) udpOpen() (err error) {

	v.Lock()
	defer v.Unlock()

	if v.wsConn == nil {
		return fmt.Errorf("nil voice websocket")
	}

	if v.udpConn != nil {
		return fmt.Errorf("udp connection already open")
	}

	if v.close == nil {
		return fmt.Errorf("nil close channel")
	}

	if v.endpoint == "" {
		return fmt.Errorf("empty endpoint")
	}

	host := v.op2.IP + ":" + strconv.Itoa(v.op2.Port)
	addr, err := net.ResolveUDPAddr("udp", host)
	if err != nil {
		v.log(LogWarning, "error resolving udp host %s, %s", host, err)
		return
	}

	v.log(LogInformational, "connecting to udp addr %s", addr.String())
	v.udpConn, err = net.DialUDP("udp", nil, addr)
	if err != nil {
		v.log(LogWarning, "error connecting to udp addr %s, %s", addr.String(), err)
		return
	}

	// Create a 70 byte array and put the SSRC code from the Op 2 VoiceConnection event
	// into it.  Then send that over the UDP connection to Discord
	sb := make([]byte, 70)
	binary.BigEndian.PutUint32(sb, v.op2.SSRC)
	_, err = v.udpConn.Write(sb)
	if err != nil {
		v.log(LogWarning, "udp write error to %s, %s", addr.String(), err)
		return
	}

	// Create a 70 byte array and listen for the initial handshake response
	// from Discord.  Once we get it parse the IP and PORT information out
	// of the response.  This should be our public IP and PORT as Discord
	// saw us.
	rb := make([]byte, 70)
	rlen, _, err := v.udpConn.ReadFromUDP(rb)
	if err != nil {
		v.log(LogWarning, "udp read error, %s, %s", addr.String(), err)
		return
	}

	if rlen < 70 {
		v.log(LogWarning, "received udp packet too small")
		return fmt.Errorf("received udp packet too small")
	}

	// Loop over position 4 through 20 to grab the IP address
	// Should never be beyond position 20.
	var ip string
	for i := 4; i < 20; i++ {
		if rb[i] == 0 {
			break
		}
		ip += string(rb[i])
	}

	// Grab port from position 68 and 69
	port := binary.BigEndian.Uint16(rb[68:70])

	// Take the data from above and send it back to Discord to finalize
	// the UDP connection handshake.
	data := voiceUDPOp{1, voiceUDPD{"udp", voiceUDPData{ip, port, "xsalsa20_poly1305"}}}

	v.wsMutex.Lock()
	err = v.wsConn.WriteJSON(data)
	v.wsMutex.Unlock()
	if err != nil {
		v.log(LogWarning, "udp write error, %#v, %s", data, err)
		return
	}

	// start udpKeepAlive
	go v.udpKeepAlive(v.udpConn, v.close, 5*time.Second)
	// TODO: find a way to check that it fired off okay

	return
}

// udpKeepAlive sends a udp packet to keep the udp connection open
// This is still a bit of a "proof of concept"
func (v *VoiceConnection) udpKeepAlive(udpConn *net.UDPConn, close <-chan struct{}, i time.Duration) {

	if udpConn == nil || close == nil {
		return
	}

	var err error
	var sequence uint64

	packet := make([]byte, 8)

	ticker := time.NewTicker(i)
	defer ticker.Stop()
	for {

		binary.LittleEndian.PutUint64(packet, sequence)
		sequence++

		_, err = udpConn.Write(packet)
		if err != nil {
			v.log(LogError, "write error, %s", err)
			return
		}

		select {
		case <-ticker.C:
			// continue loop and send keepalive
		case <-close:
			return
		}
	}
}

// opusSender will listen on the given channel and send any
// pre-encoded opus audio to Discord.  Supposedly.
func (v *VoiceConnection) opusSender(udpConn *net.UDPConn, close <-chan struct{}, opus <-chan []byte, rate, size int) {

	if udpConn == nil || close == nil {
		return
	}

	// VoiceConnection is now ready to receive audio packets
	// TODO: this needs reviewed as I think there must be a better way.
	v.Lock()
	v.Ready = true
	v.Unlock()
	defer func() {
		v.Lock()
		v.Ready = false
		v.Unlock()
	}()

	var sequence uint16
	var timestamp uint32
	var recvbuf []byte
	var ok bool
	udpHeader := make([]byte, 12)
	var nonce [24]byte

	// build the parts that don't change in the udpHeader
	udpHeader[0] = 0x80
	udpHeader[1] = 0x78
	binary.BigEndian.PutUint32(udpHeader[8:], v.op2.SSRC)

	// start a send loop that loops until buf chan is closed
	ticker := time.NewTicker(time.Millisecond * time.Duration(size/(rate/1000)))
	defer ticker.Stop()
	for {

		// Get data from chan.  If chan is closed, return.
		select {
		case <-close:
			return
		case recvbuf, ok = <-opus:
			if !ok {
				return
			}
			// else, continue loop
		}

		v.RLock()
		speaking := v.speaking
		v.RUnlock()
		if !speaking {
			err := v.Speaking(true)
			if err != nil {
				v.log(LogError, "error sending speaking packet, %s", err)
			}
		}

		// Add sequence and timestamp to udpPacket
		binary.BigEndian.PutUint16(udpHeader[2:], sequence)
		binary.BigEndian.PutUint32(udpHeader[4:], timestamp)

		// encrypt the opus data
		copy(nonce[:], udpHeader)
		v.RLock()
		sendbuf := secretbox.Seal(udpHeader, recvbuf, &nonce, &v.op4.SecretKey)
		v.RUnlock()

		// block here until we're exactly at the right time :)
		// Then send rtp audio packet to Discord over UDP
		select {
		case <-close:
			return
		case <-ticker.C:
			// continue
		}
		_, err := udpConn.Write(sendbuf)

		if err != nil {
			v.log(LogError, "udp write error, %s", err)
			v.log(LogDebug, "voice struct: %#v\n", v)
			return
		}

		if (sequence) == 0xFFFF {
			sequence = 0
		} else {
			sequence++
		}

		if (timestamp + uint32(size)) >= 0xFFFFFFFF {
			timestamp = 0
		} else {
			timestamp += uint32(size)
		}
	}
}

// A Packet contains the headers and content of a received voice packet.
type Packet struct {
	SSRC      uint32
	Sequence  uint16
	Timestamp uint32
	Type      []byte
	Opus      []byte
	PCM       []int16
}

// opusReceiver listens on the UDP socket for incoming packets
// and sends them across the given channel
// NOTE :: This function may change names later.
func (v *VoiceConnection) opusReceiver(udpConn *net.UDPConn, close <-chan struct{}, c chan *Packet) {

	if udpConn == nil || close == nil {
		return
	}

	recvbuf := make([]byte, 1024)
	var nonce [24]byte

	for {
		rlen, err := udpConn.Read(recvbuf)
		if err != nil {
			// Detect if we have been closed manually. If a Close() has already
			// happened, the udp connection we are listening on will be different
			// to the current session.
			v.RLock()
			sameConnection := v.udpConn == udpConn
			v.RUnlock()
			if sameConnection {

				v.log(LogError, "udp read error, %s, %s", v.endpoint, err)
				v.log(LogDebug, "voice struct: %#v\n", v)

				go v.reconnect()
			}
			return
		}

		select {
		case <-close:
			return
		default:
			// continue loop
		}

		// For now, skip anything except audio.
		if rlen < 12 || (recvbuf[0] != 0x80 && recvbuf[0] != 0x90) {
			continue
		}

		// build a audio packet struct
		p := Packet{}
		p.Type = recvbuf[0:2]
		p.Sequence = binary.BigEndian.Uint16(recvbuf[2:4])
		p.Timestamp = binary.BigEndian.Uint32(recvbuf[4:8])
		p.SSRC = binary.BigEndian.Uint32(recvbuf[8:12])
		// decrypt opus data
		copy(nonce[:], recvbuf[0:12])
		p.Opus, _ = secretbox.Open(nil, recvbuf[12:rlen], &nonce, &v.op4.SecretKey)

		// extension bit set, and not a RTCP packet
		if ((recvbuf[0] & 0x10) == 0x10) && ((recvbuf[1] & 0x80) == 0) {
			// get extended header length
			extlen := binary.BigEndian.Uint16(p.Opus[2:4])
			// 4 bytes (ext header header) + 4*extlen (ext header data)
			shift := int(4 + 4*extlen)
			if len(p.Opus) > shift {
				p.Opus = p.Opus[shift:]
			}
		}

		if c != nil {
			select {
			case c <- &p:
			case <-close:
				return
			}
		}
	}
}

// Reconnect will close down a voice connection then immediately try to
// reconnect to that session.
// NOTE : This func is messy and a WIP while I find what works.
// It will be cleaned up once a proven stable option is flushed out.
// aka: this is ugly shit code, please don't judge too harshly.
func (v *VoiceConnection) reconnect() {

	v.log(LogInformational, "called")

	v.Lock()
	if v.reconnecting {
		v.log(LogInformational, "already reconnecting to channel %s, exiting", v.ChannelID)
		v.Unlock()
		return
	}
	v.reconnecting = true
	v.Unlock()

	defer func() { v.reconnecting = false }()

	// Close any currently open connections
	v.Close()

	wait := time.Duration(1)
	for {

		<-time.After(wait * time.Second)
		wait *= 2
		if wait > 600 {
			wait = 600
		}

		if v.session.DataReady == false || v.session.wsConn == nil {
			v.log(LogInformational, "cannot reconnect to channel %s with unready session", v.ChannelID)
			continue
		}

		v.log(LogInformational, "trying to reconnect to channel %s", v.ChannelID)

		_, err := v.session.ChannelVoiceJoin(v.GuildID, v.ChannelID, v.mute, v.deaf)
		if err == nil {
			v.log(LogInformational, "successfully reconnected to channel %s", v.ChannelID)
			return
		}

		v.log(LogInformational, "error reconnecting to channel %s, %s", v.ChannelID, err)

		// if the reconnect above didn't work lets just send a disconnect
		// packet to reset things.
		// Send a OP4 with a nil channel to disconnect
		data := voiceChannelJoinOp{4, voiceChannelJoinData{&v.GuildID, nil, true, true}}
		v.session.wsMutex.Lock()
		err = v.session.wsConn.WriteJSON(data)
		v.session.wsMutex.Unlock()
		if err != nil {
			v.log(LogError, "error sending disconnect packet, %s", err)
		}

	}
}