~singpolyma/asterisk

ref: 51af79b42e4ae7d1831603633d73bf0df179720e asterisk/main/core_unreal.c -rw-r--r-- 27.4 KiB
51af79b4Christopher Vollick Content Created By Initiator 2: Electric Boogaloo 9 months ago
                                                                                
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
/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2013 Digium, Inc.
 *
 * Richard Mudgett <rmudgett@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*!
 * \file
 * \brief Unreal channel derivatives framework for channel drivers like local channels.
 *
 * \author Richard Mudgett <rmudgett@digium.com>
 *
 * See Also:
 * \arg \ref AstCREDITS
 */

/*** MODULEINFO
	<support_level>core</support_level>
 ***/

#include "asterisk.h"

#include "asterisk/causes.h"
#include "asterisk/channel.h"
#include "asterisk/stasis_channels.h"
#include "asterisk/pbx.h"
#include "asterisk/musiconhold.h"
#include "asterisk/astobj2.h"
#include "asterisk/bridge.h"
#include "asterisk/core_unreal.h"

static unsigned int name_sequence = 0;

void ast_unreal_lock_all(struct ast_unreal_pvt *p, struct ast_channel **outchan, struct ast_channel **outowner)
{
	struct ast_channel *chan = NULL;
	struct ast_channel *owner = NULL;

	ao2_lock(p);
	for (;;) {
		if (p->chan) {
			chan = p->chan;
			ast_channel_ref(chan);
		}
		if (p->owner) {
			owner = p->owner;
			ast_channel_ref(owner);
		}
		ao2_unlock(p);

		/* if we don't have both channels, then this is very easy */
		if (!owner || !chan) {
			if (owner) {
				ast_channel_lock(owner);
			} else if(chan) {
				ast_channel_lock(chan);
			}
		} else {
			/* lock both channels first, then get the pvt lock */
			ast_channel_lock_both(chan, owner);
		}
		ao2_lock(p);

		/* Now that we have all the locks, validate that nothing changed */
		if (p->owner != owner || p->chan != chan) {
			if (owner) {
				ast_channel_unlock(owner);
				owner = ast_channel_unref(owner);
			}
			if (chan) {
				ast_channel_unlock(chan);
				chan = ast_channel_unref(chan);
			}
			continue;
		}

		break;
	}
	*outowner = p->owner;
	*outchan = p->chan;
}

/* Called with ast locked */
int ast_unreal_setoption(struct ast_channel *ast, int option, void *data, int datalen)
{
	int res = 0;
	struct ast_unreal_pvt *p;
	struct ast_channel *otherchan = NULL;
	ast_chan_write_info_t *write_info;
	char *info_data;

	if (option != AST_OPTION_CHANNEL_WRITE) {
		return -1;
	}

	write_info = data;

	if (write_info->version != AST_CHAN_WRITE_INFO_T_VERSION) {
		ast_log(LOG_ERROR, "The chan_write_info_t type has changed, and this channel hasn't been updated!\n");
		return -1;
	}

	info_data = write_info->data;
	if (!strcmp(write_info->function, "CHANNEL")) {
		if (!strncasecmp(info_data, "hangup_handler_", 15)) {
			/* Block CHANNEL(hangup_handler_xxx) writes to the other unreal channel. */
			return 0;
		}

		/* Crossover the accountcode and peeraccount to cross the unreal bridge. */
		if (!strcasecmp(info_data, "accountcode")) {
			info_data = "peeraccount";
		} else if (!strcasecmp(info_data, "peeraccount")) {
			info_data = "accountcode";
		}
	}

	/* get the tech pvt */
	if (!(p = ast_channel_tech_pvt(ast))) {
		return -1;
	}
	ao2_ref(p, 1);
	ast_channel_unlock(ast); /* Held when called, unlock before locking another channel */

	/* get the channel we are supposed to write to */
	ao2_lock(p);
	otherchan = (write_info->chan == p->owner) ? p->chan : p->owner;
	if (!otherchan || otherchan == write_info->chan) {
		res = -1;
		otherchan = NULL;
		ao2_unlock(p);
		goto setoption_cleanup;
	}
	ast_channel_ref(otherchan);

	/* clear the pvt lock before grabbing the channel */
	ao2_unlock(p);

	ast_channel_lock(otherchan);
	res = write_info->write_fn(otherchan, write_info->function, info_data, write_info->value);
	ast_channel_unlock(otherchan);

setoption_cleanup:
	ao2_ref(p, -1);
	if (otherchan) {
		ast_channel_unref(otherchan);
	}
	ast_channel_lock(ast); /* Lock back before we leave */
	return res;
}

/* Called with ast locked */
int ast_unreal_queryoption(struct ast_channel *ast, int option, void *data, int *datalen)
{
	struct ast_unreal_pvt *p;
	struct ast_channel *peer;
	struct ast_channel *other;
	int res = 0;

	if (option != AST_OPTION_T38_STATE) {
		/* AST_OPTION_T38_STATE is the only supported option at this time */
		return -1;
	}

	/* for some reason the channel is not locked in channel.c when this function is called */
	if (!(p = ast_channel_tech_pvt(ast))) {
		return -1;
	}

	ao2_lock(p);
	other = AST_UNREAL_IS_OUTBOUND(ast, p) ? p->owner : p->chan;
	if (!other) {
		ao2_unlock(p);
		return -1;
	}
	ast_channel_ref(other);
	ao2_unlock(p);
	ast_channel_unlock(ast); /* Held when called, unlock before locking another channel */

	peer = ast_channel_bridge_peer(other);
	if (peer) {
		res = ast_channel_queryoption(peer, option, data, datalen, 0);
		ast_channel_unref(peer);
	}
	ast_channel_unref(other);
	ast_channel_lock(ast); /* Lock back before we leave */

	return res;
}

/*!
 * \brief queue a frame onto either the p->owner or p->chan
 *
 * \note the ast_unreal_pvt MUST have it's ref count bumped before entering this function and
 * decremented after this function is called.  This is a side effect of the deadlock
 * avoidance that is necessary to lock 2 channels and a tech_pvt.  Without a ref counted
 * ast_unreal_pvt, it is impossible to guarantee it will not be destroyed by another thread
 * during deadlock avoidance.
 */
static int unreal_queue_frame(struct ast_unreal_pvt *p, int isoutbound, struct ast_frame *f,
	struct ast_channel *us, int us_locked)
{
	struct ast_channel *other;

	/* Recalculate outbound channel */
	other = isoutbound ? p->owner : p->chan;
	if (!other) {
		return 0;
	}

	/* do not queue media frames if a generator is on both unreal channels */
	if (us
		&& (f->frametype == AST_FRAME_VOICE || f->frametype == AST_FRAME_VIDEO)
		&& ast_channel_generator(us)
		&& ast_channel_generator(other)) {
		return 0;
	}

	/* grab a ref on the channel before unlocking the pvt,
	 * other can not go away from us now regardless of locking */
	ast_channel_ref(other);
	if (us && us_locked) {
		ast_channel_unlock(us);
	}
	ao2_unlock(p);

	if (f->frametype == AST_FRAME_CONTROL && f->subclass.integer == AST_CONTROL_RINGING) {
		ast_setstate(other, AST_STATE_RINGING);
	}
	ast_queue_frame(other, f);

	other = ast_channel_unref(other);
	if (us && us_locked) {
		ast_channel_lock(us);
	}
	ao2_lock(p);

	return 0;
}

int ast_unreal_answer(struct ast_channel *ast)
{
	struct ast_unreal_pvt *p = ast_channel_tech_pvt(ast);
	int isoutbound;
	int res = -1;

	if (!p) {
		return -1;
	}

	ao2_ref(p, 1);
	ao2_lock(p);
	isoutbound = AST_UNREAL_IS_OUTBOUND(ast, p);
	if (isoutbound) {
		/* Pass along answer since somebody answered us */
		struct ast_frame answer = { AST_FRAME_CONTROL, { AST_CONTROL_ANSWER } };

		res = unreal_queue_frame(p, isoutbound, &answer, ast, 1);
	} else {
		ast_log(LOG_WARNING, "Huh?  %s is being asked to answer?\n",
			ast_channel_name(ast));
	}
	ao2_unlock(p);
	ao2_ref(p, -1);
	return res;
}

/*!
 * \internal
 * \brief Check and optimize out the unreal channels between bridges.
 * \since 12.0.0
 *
 * \param ast Channel writing a frame into the unreal channels.
 * \param p Unreal channel private.
 *
 * \note It is assumed that ast is locked.
 * \note It is assumed that p is locked.
 *
 * \retval 0 if unreal channels were not optimized out.
 * \retval non-zero if unreal channels were optimized out.
 */
static int got_optimized_out(struct ast_channel *ast, struct ast_unreal_pvt *p)
{
	int res = 0;

	/* Do a few conditional checks early on just to see if this optimization is possible */
	if (ast_test_flag(p, AST_UNREAL_NO_OPTIMIZATION) || !p->chan || !p->owner) {
		return res;
	}

	if (ast == p->owner) {
		res = ast_bridge_unreal_optimize_out(p->owner, p->chan, p);
	} else if (ast == p->chan) {
		res = ast_bridge_unreal_optimize_out(p->chan, p->owner, p);
	}

	return res;
}

struct ast_frame  *ast_unreal_read(struct ast_channel *ast)
{
	return &ast_null_frame;
}

int ast_unreal_write(struct ast_channel *ast, struct ast_frame *f)
{
	struct ast_unreal_pvt *p = ast_channel_tech_pvt(ast);
	int res = -1;

	if (!p) {
		return -1;
	}

	/* If we are told to write a frame with a type that has no corresponding
	 * stream on the channel then drop it.
	 */
	if (f->frametype == AST_FRAME_VOICE) {
		if (!ast_channel_get_default_stream(ast, AST_MEDIA_TYPE_AUDIO)) {
			return 0;
		}
	} else if (f->frametype == AST_FRAME_VIDEO ||
		(f->frametype == AST_FRAME_CONTROL && f->subclass.integer == AST_CONTROL_VIDUPDATE)) {
		if (!ast_channel_get_default_stream(ast, AST_MEDIA_TYPE_VIDEO)) {
			return 0;
		}
	}

	/* Just queue for delivery to the other side */
	ao2_ref(p, 1);
	ao2_lock(p);
	switch (f->frametype) {
	case AST_FRAME_VOICE:
	case AST_FRAME_VIDEO:
		if (got_optimized_out(ast, p)) {
			break;
		}
		/* fall through */
	default:
		res = unreal_queue_frame(p, AST_UNREAL_IS_OUTBOUND(ast, p), f, ast, 1);
		break;
	}
	ao2_unlock(p);
	ao2_ref(p, -1);

	return res;
}

int ast_unreal_fixup(struct ast_channel *oldchan, struct ast_channel *newchan)
{
	struct ast_unreal_pvt *p = ast_channel_tech_pvt(newchan);
	struct ast_bridge *bridge_owner;
	struct ast_bridge *bridge_chan;

	if (!p) {
		return -1;
	}

	ao2_lock(p);

	if ((p->owner != oldchan) && (p->chan != oldchan)) {
		ast_log(LOG_WARNING, "Old channel %p wasn't %p or %p\n", oldchan, p->owner, p->chan);
		ao2_unlock(p);
		return -1;
	}
	if (p->owner == oldchan) {
		p->owner = newchan;
	} else {
		p->chan = newchan;
	}

	if (ast_check_hangup(newchan) || !p->owner || !p->chan) {
		ao2_unlock(p);
		return 0;
	}

	/* Do not let a masquerade cause an unreal channel to be bridged to itself! */
	bridge_owner = ast_channel_internal_bridge(p->owner);
	bridge_chan = ast_channel_internal_bridge(p->chan);
	if (bridge_owner && bridge_owner == bridge_chan) {
		ast_log(LOG_WARNING, "You can not bridge an unreal channel (%s) to itself!\n",
			ast_channel_name(newchan));
		ao2_unlock(p);
		ast_queue_hangup(newchan);
		return -1;
	}

	ao2_unlock(p);
	return 0;
}

/*!
 * \internal
 * \brief Queue up a frame representing the indication as a control frame.
 * \since 12.0.0
 *
 * \param p Unreal private structure.
 * \param ast Channel indicating the condition.
 * \param condition What is being indicated.
 * \param data Extra data.
 * \param datalen Length of extra data.
 *
 * \retval 0 on success.
 * \retval AST_T38_REQUEST_PARMS if successful and condition is AST_CONTROL_T38_PARAMETERS.
 * \retval -1 on error.
 */
static int unreal_queue_indicate(struct ast_unreal_pvt *p, struct ast_channel *ast, int condition, const void *data, size_t datalen)
{
	int res = 0;
	int isoutbound;

	ao2_lock(p);
	/*
	 * Block -1 stop tones events if we are to be optimized out.  We
	 * don't need a flurry of these events on an unreal channel chain
	 * when initially connected to slow the optimization process.
	 */
	if (0 <= condition || ast_test_flag(p, AST_UNREAL_NO_OPTIMIZATION)) {
		struct ast_frame f = {
			.frametype = AST_FRAME_CONTROL,
			.subclass.integer = condition,
			.data.ptr = (void *) data,
			.datalen = datalen,
		};

		isoutbound = AST_UNREAL_IS_OUTBOUND(ast, p);
		res = unreal_queue_frame(p, isoutbound, &f, ast, 1);
		if (!res
			&& condition == AST_CONTROL_T38_PARAMETERS
			&& datalen == sizeof(struct ast_control_t38_parameters)) {
			const struct ast_control_t38_parameters *parameters = data;

			if (parameters->request_response == AST_T38_REQUEST_PARMS) {
				res = AST_T38_REQUEST_PARMS;
			}
		}
	} else {
		ast_debug(4, "Blocked indication %d\n", condition);
	}
	ao2_unlock(p);

	return res;
}

/*!
 * \internal
 * \brief Handle COLP and redirecting conditions.
 * \since 12.0.0
 *
 * \param p Unreal private structure.
 * \param ast Channel indicating the condition.
 * \param condition What is being indicated.
 *
 * \retval 0 on success.
 * \retval -1 on error.
 */
static int unreal_colp_redirect_indicate(struct ast_unreal_pvt *p, struct ast_channel *ast, int condition)
{
	struct ast_channel *my_chan;
	struct ast_channel *my_owner;
	struct ast_channel *this_channel;
	struct ast_channel *the_other_channel;
	int isoutbound;
	int res = 0;
	unsigned char frame_data[1024];
	struct ast_frame f = {
		.frametype = AST_FRAME_CONTROL,
		.subclass.integer = condition,
		.data.ptr = frame_data,
	};

	/*
	 * A connected line update frame may only contain a partial
	 * amount of data, such as just a source, or just a ton, and not
	 * the full amount of information.  However, the collected
	 * information is all stored in the outgoing channel's
	 * connectedline structure, so when receiving a connected line
	 * update on an outgoing unreal channel, we need to transmit the
	 * collected connected line information instead of whatever
	 * happens to be in this control frame.  The same applies for
	 * redirecting information, which is why it is handled here as
	 * well.
	 */
	ast_channel_unlock(ast);
	ast_unreal_lock_all(p, &my_chan, &my_owner);
	isoutbound = AST_UNREAL_IS_OUTBOUND(ast, p);
	if (isoutbound) {
		this_channel = p->chan;
		the_other_channel = p->owner;
	} else {
		this_channel = p->owner;
		the_other_channel = p->chan;
	}
	if (the_other_channel) {
		if (condition == AST_CONTROL_CONNECTED_LINE) {
			ast_connected_line_copy_to_caller(ast_channel_caller(the_other_channel),
				ast_channel_connected(this_channel));
			f.datalen = ast_connected_line_build_data(frame_data, sizeof(frame_data),
				ast_channel_connected(this_channel), NULL);
		} else {
			f.datalen = ast_redirecting_build_data(frame_data, sizeof(frame_data),
				ast_channel_redirecting(this_channel), NULL);
		}
	}
	if (my_chan) {
		ast_channel_unlock(my_chan);
		ast_channel_unref(my_chan);
	}
	if (my_owner) {
		ast_channel_unlock(my_owner);
		ast_channel_unref(my_owner);
	}
	if (the_other_channel) {
		res = unreal_queue_frame(p, isoutbound, &f, ast, 0);
	}
	ao2_unlock(p);
	ast_channel_lock(ast);

	return res;
}

int ast_unreal_indicate(struct ast_channel *ast, int condition, const void *data, size_t datalen)
{
	struct ast_unreal_pvt *p = ast_channel_tech_pvt(ast);
	int res = 0;

	if (!p) {
		return -1;
	}

	ao2_ref(p, 1); /* ref for unreal_queue_frame */

	switch (condition) {
	case AST_CONTROL_MASQUERADE_NOTIFY:
		/*
		 * Always block this because this is the channel being
		 * masqueraded; not anything down the chain.
		 */
		break;
	case AST_CONTROL_CONNECTED_LINE:
	case AST_CONTROL_REDIRECTING:
		res = unreal_colp_redirect_indicate(p, ast, condition);
		break;
	case AST_CONTROL_HOLD:
		if (ast_test_flag(p, AST_UNREAL_MOH_INTERCEPT)) {
			ast_moh_start(ast, data, NULL);
			break;
		}
		res = unreal_queue_indicate(p, ast, condition, data, datalen);
		break;
	case AST_CONTROL_UNHOLD:
		if (ast_test_flag(p, AST_UNREAL_MOH_INTERCEPT)) {
			ast_moh_stop(ast);
			break;
		}
		res = unreal_queue_indicate(p, ast, condition, data, datalen);
		break;
	case AST_CONTROL_RINGING:
		/* Don't queue ringing frames if the channel is not in a "ring" state. Otherwise,
		 * the real channel on the other end will likely start a playtones generator. It is
		 * possible that this playtones generator will never be stopped under certain
		 * circumstances.
		 */
		if (ast_channel_state(ast) == AST_STATE_RING) {
			res = unreal_queue_indicate(p, ast, condition, data, datalen);
		} else {
			res = -1;
		}
		break;
	case AST_CONTROL_PVT_CAUSE_CODE:
		/* Return -1 so that asterisk core will correctly set up hangupcauses. */
		unreal_queue_indicate(p, ast, condition, data, datalen);
		res = -1;
		break;
	default:
		res = unreal_queue_indicate(p, ast, condition, data, datalen);
		break;
	}

	ao2_ref(p, -1);
	return res;
}

int ast_unreal_digit_begin(struct ast_channel *ast, char digit)
{
	struct ast_unreal_pvt *p = ast_channel_tech_pvt(ast);
	int res = -1;
	struct ast_frame f = { AST_FRAME_DTMF_BEGIN, };
	int isoutbound;

	if (!p) {
		return -1;
	}

	ao2_ref(p, 1); /* ref for unreal_queue_frame */
	ao2_lock(p);
	isoutbound = AST_UNREAL_IS_OUTBOUND(ast, p);
	f.subclass.integer = digit;
	res = unreal_queue_frame(p, isoutbound, &f, ast, 0);
	ao2_unlock(p);
	ao2_ref(p, -1);

	return res;
}

int ast_unreal_digit_end(struct ast_channel *ast, char digit, unsigned int duration)
{
	struct ast_unreal_pvt *p = ast_channel_tech_pvt(ast);
	int res = -1;
	struct ast_frame f = { AST_FRAME_DTMF_END, };
	int isoutbound;

	if (!p) {
		return -1;
	}

	ao2_ref(p, 1); /* ref for unreal_queue_frame */
	ao2_lock(p);
	isoutbound = AST_UNREAL_IS_OUTBOUND(ast, p);
	f.subclass.integer = digit;
	f.len = duration;
	res = unreal_queue_frame(p, isoutbound, &f, ast, 0);
	ao2_unlock(p);
	ao2_ref(p, -1);

	return res;
}

int ast_unreal_sendtext(struct ast_channel *ast, const char *text)
{
	struct ast_unreal_pvt *p = ast_channel_tech_pvt(ast);
	int res = -1;
	struct ast_frame f = { AST_FRAME_TEXT, };
	int isoutbound;

	if (!p) {
		return -1;
	}

	ao2_ref(p, 1); /* ref for unreal_queue_frame */
	ao2_lock(p);
	isoutbound = AST_UNREAL_IS_OUTBOUND(ast, p);
	f.data.ptr = (char *) text;
	f.datalen = strlen(text) + 1;
	res = unreal_queue_frame(p, isoutbound, &f, ast, 0);
	ao2_unlock(p);
	ao2_ref(p, -1);
	return res;
}

int ast_unreal_sendhtml(struct ast_channel *ast, int subclass, const char *data, int datalen)
{
	struct ast_unreal_pvt *p = ast_channel_tech_pvt(ast);
	int res = -1;
	struct ast_frame f = { AST_FRAME_HTML, };
	int isoutbound;

	if (!p) {
		return -1;
	}

	ao2_ref(p, 1); /* ref for unreal_queue_frame */
	ao2_lock(p);
	isoutbound = AST_UNREAL_IS_OUTBOUND(ast, p);
	f.subclass.integer = subclass;
	f.data.ptr = (char *)data;
	f.datalen = datalen;
	res = unreal_queue_frame(p, isoutbound, &f, ast, 0);
	ao2_unlock(p);
	ao2_ref(p, -1);

	return res;
}

void ast_unreal_call_setup(struct ast_channel *semi1, struct ast_channel *semi2)
{
	struct ast_var_t *varptr;
	struct ast_var_t *clone_var;

	ast_channel_stage_snapshot(semi2);

	/*
	 * Note that cid_num and cid_name aren't passed in the
	 * ast_channel_alloc calls in ast_unreal_new_channels().  It's
	 * done here instead.
	 */
	ast_party_redirecting_copy(ast_channel_redirecting(semi2), ast_channel_redirecting(semi1));

	ast_party_dialed_copy(ast_channel_dialed(semi2), ast_channel_dialed(semi1));

	/* Crossover the CallerID and conected-line to cross the unreal bridge. */
	ast_connected_line_copy_to_caller(ast_channel_caller(semi2), ast_channel_connected(semi1));
	ast_connected_line_copy_from_caller(ast_channel_connected(semi2), ast_channel_caller(semi1));

	ast_channel_language_set(semi2, ast_channel_language(semi1));
	ast_channel_musicclass_set(semi2, ast_channel_musicclass(semi1));
	ast_channel_parkinglot_set(semi2, ast_channel_parkinglot(semi1));

	/* Crossover the accountcode and peeraccount to cross the unreal bridge. */
	ast_channel_accountcode_set(semi2, ast_channel_peeraccount(semi1));
	ast_channel_peeraccount_set(semi2, ast_channel_accountcode(semi1));

	ast_channel_cc_params_init(semi2, ast_channel_get_cc_config_params(semi1));

	/*
	 * Make sure we inherit the AST_CAUSE_ANSWERED_ELSEWHERE if it's
	 * set on the queue/dial call request in the dialplan.
	 */
	if (ast_channel_hangupcause(semi1) == AST_CAUSE_ANSWERED_ELSEWHERE) {
		ast_channel_hangupcause_set(semi2, AST_CAUSE_ANSWERED_ELSEWHERE);
	}

	/*
	 * Copy the channel variables from the semi1 channel to the
	 * outgoing channel.
	 *
	 * Note that due to certain assumptions, they MUST be in the
	 * same order.
	 */
	AST_LIST_TRAVERSE(ast_channel_varshead(semi1), varptr, entries) {
		clone_var = ast_var_assign(varptr->name, varptr->value);
		if (clone_var) {
			AST_LIST_INSERT_TAIL(ast_channel_varshead(semi2), clone_var, entries);
			ast_channel_publish_varset(semi2, ast_var_full_name(clone_var),
				ast_var_value(clone_var));
		}
	}
	ast_channel_datastore_inherit(semi1, semi2);

	ast_channel_stage_snapshot_done(semi2);
}

int ast_unreal_channel_push_to_bridge(struct ast_channel *ast, struct ast_bridge *bridge, unsigned int flags)
{
	struct ast_bridge_features *features;
	struct ast_channel *chan;
	struct ast_channel *owner;
	ast_callid bridge_callid;
	RAII_VAR(struct ast_unreal_pvt *, p, NULL, ao2_cleanup);

	ast_bridge_lock(bridge);
	bridge_callid = bridge->callid;
	ast_bridge_unlock(bridge);

	{
		SCOPED_CHANNELLOCK(lock, ast);
		p = ast_channel_tech_pvt(ast);
		if (!p) {
			return -1;
		}
		ao2_ref(p, +1);
	}

	{
		SCOPED_AO2LOCK(lock, p);
		chan = p->chan;
		if (!chan) {
			return -1;
		}

		owner = p->owner;
		if (!owner) {
			return -1;
		}

		ast_channel_ref(chan);
		ast_channel_ref(owner);
	}

	if (bridge_callid) {
		ast_callid chan_callid;
		ast_callid owner_callid;

		/* chan side call ID setting */
		ast_channel_lock(chan);

		chan_callid = ast_channel_callid(chan);
		if (!chan_callid) {
			ast_channel_callid_set(chan, bridge_callid);
		}
		ast_channel_unlock(chan);

		/* owner side call ID setting */
		ast_channel_lock(owner);

		owner_callid = ast_channel_callid(owner);
		if (!owner_callid) {
			ast_channel_callid_set(owner, bridge_callid);
		}

		ast_channel_unlock(owner);
	}

	/* We are done with the owner now that its call ID matches the bridge */
	ast_channel_unref(owner);
	owner = NULL;

	features = ast_bridge_features_new();
	if (!features) {
		ast_channel_unref(chan);
		return -1;
	}

	ast_set_flag(&features->feature_flags, flags);

	/* Impart the semi2 channel into the bridge */
	if (ast_bridge_impart(bridge, chan, NULL, features,
		AST_BRIDGE_IMPART_CHAN_INDEPENDENT)) {
		ast_channel_unref(chan);
		return -1;
	}

	/* The bridge thread now controls the chan ref from the ast_unreal_pvt */
	ao2_lock(p);
	ast_set_flag(p, AST_UNREAL_CARETAKER_THREAD);
	ao2_unlock(p);

	ast_channel_unref(chan);

	return 0;
}

int ast_unreal_hangup(struct ast_unreal_pvt *p, struct ast_channel *ast)
{
	int hangup_chan = 0;
	int res = 0;
	int cause;
	struct ast_channel *owner = NULL;
	struct ast_channel *chan = NULL;

	/* the pvt isn't going anywhere, it has a ref */
	ast_channel_unlock(ast);

	/* lock everything */
	ast_unreal_lock_all(p, &chan, &owner);

	if (ast != chan && ast != owner) {
		res = -1;
		goto unreal_hangup_cleanup;
	}

	cause = ast_channel_hangupcause(ast);

	if (ast == p->chan) {
		/* Outgoing side is hanging up. */
		ast_clear_flag(p, AST_UNREAL_CARETAKER_THREAD);
		p->chan = NULL;
		if (p->owner) {
			const char *status = pbx_builtin_getvar_helper(p->chan, "DIALSTATUS");

			if (status) {
				ast_channel_hangupcause_set(p->owner, cause);
				pbx_builtin_setvar_helper(p->owner, "CHANLOCALSTATUS", status);
			}
			ast_queue_hangup_with_cause(p->owner, cause);
		}
	} else {
		/* Owner side is hanging up. */
		p->owner = NULL;
		if (p->chan) {
			if (cause == AST_CAUSE_ANSWERED_ELSEWHERE) {
				ast_channel_hangupcause_set(p->chan, AST_CAUSE_ANSWERED_ELSEWHERE);
				ast_debug(2, "%s has AST_CAUSE_ANSWERED_ELSEWHERE set.\n",
					ast_channel_name(p->chan));
			}
			if (!ast_test_flag(p, AST_UNREAL_CARETAKER_THREAD)) {
				/*
				 * Need to actually hangup p->chan since nothing else is taking
				 * care of it.
				 */
				hangup_chan = 1;
			} else {
				ast_queue_hangup_with_cause(p->chan, cause);
			}
		}
	}

	/* this is one of our locked channels, doesn't matter which */
	ast_channel_tech_pvt_set(ast, NULL);
	ao2_ref(p, -1);

unreal_hangup_cleanup:
	ao2_unlock(p);
	if (owner) {
		ast_channel_unlock(owner);
		ast_channel_unref(owner);
	}
	if (chan) {
		ast_channel_unlock(chan);
		if (hangup_chan) {
			ast_hangup(chan);
		}
		ast_channel_unref(chan);
	}

	/* leave with the channel locked that came in */
	ast_channel_lock(ast);

	return res;
}

void ast_unreal_destructor(void *vdoomed)
{
	struct ast_unreal_pvt *doomed = vdoomed;

	ao2_cleanup(doomed->reqcap);
	doomed->reqcap = NULL;
}

struct ast_unreal_pvt *ast_unreal_alloc(size_t size, ao2_destructor_fn destructor, struct ast_format_cap *cap)
{
	struct ast_unreal_pvt *unreal;

	static const struct ast_jb_conf jb_conf = {
		.flags = 0,
		.max_size = -1,
		.resync_threshold = -1,
		.impl = "",
		.target_extra = -1,
	};

	unreal = ao2_alloc(size, destructor);
	if (!unreal) {
		return NULL;
	}

	unreal->reqcap = ast_format_cap_alloc(AST_FORMAT_CAP_FLAG_DEFAULT);
	if (!unreal->reqcap) {
		ao2_ref(unreal, -1);
		return NULL;
	}
	ast_format_cap_append_from_cap(unreal->reqcap, cap, AST_MEDIA_TYPE_UNKNOWN);

	memcpy(&unreal->jb_conf, &jb_conf, sizeof(unreal->jb_conf));

	return unreal;
}

struct ast_channel *ast_unreal_new_channels(struct ast_unreal_pvt *p,
	const struct ast_channel_tech *tech, int semi1_state, int semi2_state,
	const char *exten, const char *context, const struct ast_assigned_ids *assignedids,
	const struct ast_channel *requestor, ast_callid callid)
{
	struct ast_channel *owner;
	struct ast_channel *chan;
	RAII_VAR(struct ast_format *, fmt, NULL, ao2_cleanup);
	struct ast_assigned_ids id1 = {NULL, NULL};
	struct ast_assigned_ids id2 = {NULL, NULL};
	int generated_seqno = ast_atomic_fetchadd_int((int *) &name_sequence, +1);

	/* set unique ids for the two channels */
	if (assignedids && !ast_strlen_zero(assignedids->uniqueid)) {
		id1.uniqueid = assignedids->uniqueid;
		id2.uniqueid = assignedids->uniqueid2;
	}

	/* if id1 given but not id2, use default of id1;2 */
	if (id1.uniqueid && ast_strlen_zero(id2.uniqueid)) {
		char *uniqueid2;

		uniqueid2 = ast_alloca(strlen(id1.uniqueid) + 3);
		strcpy(uniqueid2, id1.uniqueid);/* Safe */
		strcat(uniqueid2, ";2");/* Safe */
		id2.uniqueid = uniqueid2;
	}

	/*
	 * Allocate two new Asterisk channels
	 *
	 * Make sure that the ;2 channel gets the same linkedid as ;1.
	 * You can't pass linkedid to both allocations since if linkedid
	 * isn't set, then each channel will generate its own linkedid.
	 */
	owner = ast_channel_alloc(1, semi1_state, NULL, NULL, NULL,
		exten, context, &id1, requestor, 0,
		"%s/%s-%08x;1", tech->type, p->name, (unsigned)generated_seqno);
	if (!owner) {
		ast_log(LOG_WARNING, "Unable to allocate owner channel structure\n");
		return NULL;
	}

	if (callid) {
		ast_channel_callid_set(owner, callid);
	}

	ast_channel_tech_set(owner, tech);
	ao2_ref(p, +1);
	ast_channel_tech_pvt_set(owner, p);

	ast_channel_nativeformats_set(owner, p->reqcap);

	/* Determine our read/write format and set it on each channel */
	fmt = ast_format_cap_get_format(p->reqcap, 0);
	if (!fmt) {
		ast_channel_tech_pvt_set(owner, NULL);
		ao2_ref(p, -1);
		ast_channel_unlock(owner);
		ast_channel_release(owner);
		return NULL;
	}

	ast_channel_set_writeformat(owner, fmt);
	ast_channel_set_rawwriteformat(owner, fmt);
	ast_channel_set_readformat(owner, fmt);
	ast_channel_set_rawreadformat(owner, fmt);

	ast_set_flag(ast_channel_flags(owner), AST_FLAG_DISABLE_DEVSTATE_CACHE);

	ast_jb_configure(owner, &p->jb_conf);

	if (ast_channel_cc_params_init(owner, requestor
		? ast_channel_get_cc_config_params((struct ast_channel *) requestor) : NULL)) {
		ast_channel_tech_pvt_set(owner, NULL);
		ao2_ref(p, -1);
		ast_channel_tech_pvt_set(owner, NULL);
		ast_channel_unlock(owner);
		ast_channel_release(owner);
		return NULL;
	}

	p->owner = owner;
	ast_channel_unlock(owner);

	chan = ast_channel_alloc(1, semi2_state, NULL, NULL, NULL,
		exten, context, &id2, owner, 0,
		"%s/%s-%08x;2", tech->type, p->name, (unsigned)generated_seqno);
	if (!chan) {
		ast_log(LOG_WARNING, "Unable to allocate chan channel structure\n");
		ast_channel_tech_pvt_set(owner, NULL);
		ao2_ref(p, -1);
		ast_channel_tech_pvt_set(owner, NULL);
		ast_channel_release(owner);
		return NULL;
	}

	if (callid) {
		ast_channel_callid_set(chan, callid);
	}

	ast_channel_tech_set(chan, tech);
	ao2_ref(p, +1);
	ast_channel_tech_pvt_set(chan, p);

	ast_channel_nativeformats_set(chan, p->reqcap);

	/* Format was already determined when setting up owner */
	ast_channel_set_writeformat(chan, fmt);
	ast_channel_set_rawwriteformat(chan, fmt);
	ast_channel_set_readformat(chan, fmt);
	ast_channel_set_rawreadformat(chan, fmt);

	ast_set_flag(ast_channel_flags(chan), AST_FLAG_DISABLE_DEVSTATE_CACHE);

	p->chan = chan;
	ast_channel_unlock(chan);

	return owner;
}