~singpolyma/asterisk

ref: 51af79b42e4ae7d1831603633d73bf0df179720e asterisk/main/message.c -rw-r--r-- 40.3 KiB
51af79b4Christopher Vollick Content Created By Initiator 2: Electric Boogaloo 10 months ago
                                                                                
130ba7ae Bernhard Schmidt
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
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2010, Digium, Inc.
 *
 * Russell Bryant <russell@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 Out-of-call text message support
 *
 * \author Russell Bryant <russell@digium.com>
 */

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

#include "asterisk.h"

#include "asterisk/_private.h"

#include "asterisk/module.h"
#include "asterisk/datastore.h"
#include "asterisk/pbx.h"
#include "asterisk/manager.h"
#include "asterisk/strings.h"
#include "asterisk/astobj2.h"
#include "asterisk/vector.h"
#include "asterisk/app.h"
#include "asterisk/taskprocessor.h"
#include "asterisk/message.h"

/*** DOCUMENTATION
	<function name="MESSAGE" language="en_US">
		<synopsis>
			Create a message or read fields from a message.
		</synopsis>
		<syntax argsep="/">
			<parameter name="argument" required="true">
			<para>Field of the message to get or set.</para>
			<enumlist>
				<enum name="to">
					<para>Read-only.  The destination of the message.  When processing an
					incoming message, this will be set to the destination listed as
					the recipient of the message that was received by Asterisk.</para>
				</enum>
				<enum name="from">
					<para>Read-only.  The source of the message.  When processing an
					incoming message, this will be set to the source of the message.</para>
				</enum>
				<enum name="custom_data">
					<para>Write-only.  Mark or unmark all message headers for an outgoing
					message.  The following values can be set:</para>
					<enumlist>
						<enum name="mark_all_outbound">
							<para>Mark all headers for an outgoing message.</para>
						</enum>
						<enum name="clear_all_outbound">
							<para>Unmark all headers for an outgoing message.</para>
						</enum>
					</enumlist>
				</enum>
				<enum name="body">
					<para>Read/Write.  The message body.  When processing an incoming
					message, this includes the body of the message that Asterisk
					received.  When MessageSend() is executed, the contents of this
					field are used as the body of the outgoing message.  The body
					will always be UTF-8.</para>
				</enum>
			</enumlist>
			</parameter>
		</syntax>
		<description>
			<para>This function will read from or write a value to a text message.
			It is used both to read the data out of an incoming message, as well as
			modify or create a message that will be sent outbound.</para>
		</description>
		<see-also>
			<ref type="application">MessageSend</ref>
		</see-also>
	</function>
	<function name="MESSAGE_DATA" language="en_US">
		<synopsis>
			Read or write custom data attached to a message.
		</synopsis>
		<syntax argsep="/">
			<parameter name="argument" required="true">
			<para>Field of the message to get or set.</para>
			</parameter>
		</syntax>
		<description>
			<para>This function will read from or write a value to a text message.
			It is used both to read the data out of an incoming message, as well as
			modify a message that will be sent outbound.</para>
			<note>
				<para>If you want to set an outbound message to carry data in the
				current message, do
				Set(MESSAGE_DATA(<replaceable>key</replaceable>)=${MESSAGE_DATA(<replaceable>key</replaceable>)}).</para>
			</note>
		</description>
		<see-also>
			<ref type="application">MessageSend</ref>
		</see-also>
	</function>
	<application name="MessageSend" language="en_US">
		<synopsis>
			Send a text message.
		</synopsis>
		<syntax>
			<parameter name="to" required="true">
				<para>A To URI for the message.</para>
				<xi:include xpointer="xpointer(/docs/info[@name='MessageToInfo'])" />
			</parameter>
			<parameter name="from" required="false">
				<para>A From URI for the message if needed for the
				message technology being used to send this message. This can be a
				SIP(S) URI, such as <literal>Alice &lt;sip:alice@atlanta.com&gt;</literal>,
				a string in the format <literal>alice@atlanta.com</literal>, or simply
				a username such as <literal>alice</literal>.</para>
			</parameter>
		</syntax>
		<description>
			<para>Send a text message.  The body of the message that will be
			sent is what is currently set to <literal>MESSAGE(body)</literal>.
			  The technology chosen for sending the message is determined
			based on a prefix to the <literal>to</literal> parameter.</para>
			<para>This application sets the following channel variables:</para>
			<variablelist>
				<variable name="MESSAGE_SEND_STATUS">
					<para>This is the message delivery status returned by this application.</para>
					<value name="INVALID_PROTOCOL">
						No handler for the technology part of the URI was found.
					</value>
					<value name="INVALID_URI">
						The protocol handler reported that the URI was not valid.
					</value>
					<value name="SUCCESS">
						Successfully passed on to the protocol handler, but delivery has not necessarily been guaranteed.
					</value>
					<value name="FAILURE">
						The protocol handler reported that it was unabled to deliver the message for some reason.
					</value>
				</variable>
			</variablelist>
		</description>
	</application>
	<manager name="MessageSend" language="en_US">
		<synopsis>
			Send an out of call message to an endpoint.
		</synopsis>
		<syntax>
			<xi:include xpointer="xpointer(/docs/manager[@name='Login']/syntax/parameter[@name='ActionID'])" />
			<parameter name="To" required="true">
				<para>The URI the message is to be sent to.</para>
				<xi:include xpointer="xpointer(/docs/info[@name='MessageToInfo'])" />
			</parameter>
			<parameter name="From">
				<para>A From URI for the message if needed for the
				message technology being used to send this message.</para>
				<xi:include xpointer="xpointer(/docs/info[@name='MessageFromInfo'])" />
			</parameter>
			<parameter name="Body">
				<para>The message body text.  This must not contain any newlines as that
				conflicts with the AMI protocol.</para>
			</parameter>
			<parameter name="Base64Body">
				<para>Text bodies requiring the use of newlines have to be base64 encoded
				in this field.  Base64Body will be decoded before being sent out.
				Base64Body takes precedence over Body.</para>
			</parameter>
			<parameter name="Variable">
				<para>Message variable to set, multiple Variable: headers are
				allowed.  The header value is a comma separated list of
				name=value pairs.</para>
			</parameter>
		</syntax>
	</manager>
 ***/

struct msg_data {
	AST_DECLARE_STRING_FIELDS(
		AST_STRING_FIELD(name);
		AST_STRING_FIELD(value);
	);
	unsigned int send; /* Whether to send out on outbound messages */
};

AST_LIST_HEAD_NOLOCK(outhead, msg_data);

/*!
 * \brief A message.
 */
struct ast_msg {
	AST_DECLARE_STRING_FIELDS(
		/*! Where the message is going */
		AST_STRING_FIELD(to);
		/*! Where we "say" the message came from */
		AST_STRING_FIELD(from);
		/*! The text to send */
		AST_STRING_FIELD(body);
		/*! The dialplan context for the message */
		AST_STRING_FIELD(context);
		/*! The dialplan extension for the message */
		AST_STRING_FIELD(exten);
		/*! An endpoint associated with this message */
		AST_STRING_FIELD(endpoint);
		/*! The technology of the endpoint associated with this message */
		AST_STRING_FIELD(tech);
	);
	/*! Technology/dialplan specific variables associated with the message */
	struct ao2_container *vars;
};

/*! \brief Lock for \c msg_techs vector */
static ast_rwlock_t msg_techs_lock;

/*! \brief Vector of message technologies */
AST_VECTOR(, const struct ast_msg_tech *) msg_techs;

/*! \brief Lock for \c msg_handlers vector */
static ast_rwlock_t msg_handlers_lock;

/*! \brief Vector of received message handlers */
AST_VECTOR(, const struct ast_msg_handler *) msg_handlers;

static struct ast_taskprocessor *msg_q_tp;

static const char app_msg_send[] = "MessageSend";

static void msg_ds_destroy(void *data);

static const struct ast_datastore_info msg_datastore = {
	.type = "message",
	.destroy = msg_ds_destroy,
};

static int msg_func_read(struct ast_channel *chan, const char *function,
		char *data, char *buf, size_t len);
static int msg_func_write(struct ast_channel *chan, const char *function,
		char *data, const char *value);

static struct ast_custom_function msg_function = {
	.name = "MESSAGE",
	.read = msg_func_read,
	.write = msg_func_write,
};

static int msg_data_func_read(struct ast_channel *chan, const char *function,
		char *data, char *buf, size_t len);
static int msg_data_func_write(struct ast_channel *chan, const char *function,
		char *data, const char *value);

static struct ast_custom_function msg_data_function = {
	.name = "MESSAGE_DATA",
	.read = msg_data_func_read,
	.write = msg_data_func_write,
};

static struct ast_frame *chan_msg_read(struct ast_channel *chan);
static int chan_msg_write(struct ast_channel *chan, struct ast_frame *fr);
static int chan_msg_indicate(struct ast_channel *chan, int condition,
		const void *data, size_t datalen);
static int chan_msg_send_digit_begin(struct ast_channel *chan, char digit);
static int chan_msg_send_digit_end(struct ast_channel *chan, char digit,
		unsigned int duration);

/*!
 * \internal
 * \brief A bare minimum channel technology
 *
 * This will not be registered as we never want anything to try
 * to create Message channels other than internally in this file.
 */
static const struct ast_channel_tech msg_chan_tech_hack = {
	.type             = "Message",
	.description      = "Internal Text Message Processing",
	.read             = chan_msg_read,
	.write            = chan_msg_write,
	.indicate         = chan_msg_indicate,
	.send_digit_begin = chan_msg_send_digit_begin,
	.send_digit_end   = chan_msg_send_digit_end,
};

/*!
 * \internal
 * \brief ast_channel_tech read callback
 *
 * This should never be called.  However, we say that about chan_iax2's
 * read callback, too, and it seems to randomly get called for some
 * reason.  If it does, a simple NULL frame will suffice.
 */
static struct ast_frame *chan_msg_read(struct ast_channel *chan)
{
	return &ast_null_frame;
}

/*!
 * \internal
 * \brief ast_channel_tech write callback
 *
 * Throw all frames away.  We don't care about any of them.
 */
static int chan_msg_write(struct ast_channel *chan, struct ast_frame *fr)
{
	return 0;
}

/*!
 * \internal
 * \brief ast_channel_tech indicate callback
 *
 * The indicate callback is here just so it can return success.
 * We don't want any callers of ast_indicate() to think something
 * has failed.  We also don't want ast_indicate() itself to try
 * to generate inband tones since we didn't tell it that we took
 * care of it ourselves.
 */
static int chan_msg_indicate(struct ast_channel *chan, int condition,
		const void *data, size_t datalen)
{
	return 0;
}

/*!
 * \internal
 * \brief ast_channel_tech send_digit_begin callback
 *
 * This is here so that just in case a digit comes at a message channel
 * that the Asterisk core doesn't waste any time trying to generate
 * inband DTMF in audio.  It's a waste of resources.
 */
static int chan_msg_send_digit_begin(struct ast_channel *chan, char digit)
{
	return 0;
}

/*!
 * \internal
 * \brief ast_channel_tech send_digit_end callback
 *
 * This is here so that just in case a digit comes at a message channel
 * that the Asterisk core doesn't waste any time trying to generate
 * inband DTMF in audio.  It's a waste of resources.
 */
static int chan_msg_send_digit_end(struct ast_channel *chan, char digit,
		unsigned int duration)
{
	return 0;
}

static void msg_ds_destroy(void *data)
{
	struct ast_msg *msg = data;

	ao2_ref(msg, -1);
}

static int msg_data_cmp_fn(void *obj, void *arg, int flags)
{
	const struct msg_data *one = obj, *two = arg;
	return !strcasecmp(one->name, two->name) ? CMP_MATCH | CMP_STOP : 0;
}

static void msg_data_destructor(void *obj)
{
	struct msg_data *data = obj;
	ast_string_field_free_memory(data);
}

static void msg_destructor(void *obj)
{
	struct ast_msg *msg = obj;

	ast_string_field_free_memory(msg);
	ao2_cleanup(msg->vars);
}

struct ast_msg *ast_msg_alloc(void)
{
	struct ast_msg *msg;

	if (!(msg = ao2_alloc(sizeof(*msg), msg_destructor))) {
		return NULL;
	}

	if (ast_string_field_init(msg, 128)) {
		ao2_ref(msg, -1);
		return NULL;
	}

	msg->vars = ao2_container_alloc_list(AO2_ALLOC_OPT_LOCK_MUTEX, 0,
		NULL, msg_data_cmp_fn);
	if (!msg->vars) {
		ao2_ref(msg, -1);
		return NULL;
	}
	ast_string_field_set(msg, context, "default");

	return msg;
}

struct ast_msg *ast_msg_ref(struct ast_msg *msg)
{
	ao2_ref(msg, 1);
	return msg;
}

struct ast_msg *ast_msg_destroy(struct ast_msg *msg)
{
	ao2_ref(msg, -1);
	return NULL;
}

int ast_msg_set_to(struct ast_msg *msg, const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	ast_string_field_build_va(msg, to, fmt, ap);
	va_end(ap);

	return 0;
}

int ast_msg_set_from(struct ast_msg *msg, const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	ast_string_field_build_va(msg, from, fmt, ap);
	va_end(ap);

	return 0;
}

int ast_msg_set_body(struct ast_msg *msg, const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	ast_string_field_build_va(msg, body, fmt, ap);
	va_end(ap);

	return 0;
}

int ast_msg_set_context(struct ast_msg *msg, const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	ast_string_field_build_va(msg, context, fmt, ap);
	va_end(ap);

	return 0;
}

int ast_msg_set_exten(struct ast_msg *msg, const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	ast_string_field_build_va(msg, exten, fmt, ap);
	va_end(ap);

	return 0;
}

int ast_msg_set_tech(struct ast_msg *msg, const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	ast_string_field_build_va(msg, tech, fmt, ap);
	va_end(ap);

	return 0;
}

int ast_msg_set_endpoint(struct ast_msg *msg, const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	ast_string_field_build_va(msg, endpoint, fmt, ap);
	va_end(ap);

	return 0;
}

const char *ast_msg_get_body(const struct ast_msg *msg)
{
	return msg->body;
}

const char *ast_msg_get_from(const struct ast_msg *msg)
{
	return msg->from;
}

const char *ast_msg_get_to(const struct ast_msg *msg)
{
	return msg->to;
}

const char *ast_msg_get_tech(const struct ast_msg *msg)
{
	return msg->tech;
}

const char *ast_msg_get_endpoint(const struct ast_msg *msg)
{
	return msg->endpoint;
}

static struct msg_data *msg_data_alloc(void)
{
	struct msg_data *data;

	if (!(data = ao2_alloc(sizeof(*data), msg_data_destructor))) {
		return NULL;
	}

	if (ast_string_field_init(data, 32)) {
		ao2_ref(data, -1);
		return NULL;
	}

	return data;
}

static struct msg_data *msg_data_find(struct ao2_container *vars, const char *name)
{
	struct msg_data tmp = {
		.name = name,
	};
	return ao2_find(vars, &tmp, OBJ_POINTER);
}

static int msg_set_var_full(struct ast_msg *msg, const char *name, const char *value, unsigned int outbound)
{
	struct msg_data *data;

	if (!(data = msg_data_find(msg->vars, name))) {
		if (ast_strlen_zero(value)) {
			return 0;
		}
		if (!(data = msg_data_alloc())) {
			return -1;
		};

		ast_string_field_set(data, name, name);
		ast_string_field_set(data, value, value);
		data->send = outbound;
		ao2_link(msg->vars, data);
	} else {
		if (ast_strlen_zero(value)) {
			ao2_unlink(msg->vars, data);
		} else {
			ast_string_field_set(data, value, value);
			data->send = outbound;
		}
	}

	ao2_ref(data, -1);

	return 0;
}

int ast_msg_set_var_outbound(struct ast_msg *msg, const char *name, const char *value)
{
	return msg_set_var_full(msg, name, value, 1);
}

int ast_msg_set_var(struct ast_msg *msg, const char *name, const char *value)
{
	return msg_set_var_full(msg, name, value, 0);
}

const char *ast_msg_get_var(struct ast_msg *msg, const char *name)
{
	struct msg_data *data;
	const char *val = NULL;

	if (!(data = msg_data_find(msg->vars, name))) {
		return NULL;
	}

	/* Yep, this definitely looks like val would be a dangling pointer
	 * after the ref count is decremented.  As long as the message structure
	 * is used in a thread safe manner, this will not be the case though.
	 * The ast_msg holds a reference to this object in the msg->vars container. */
	val = data->value;
	ao2_ref(data, -1);

	return val;
}

struct ast_msg_var_iterator {
	struct ao2_iterator iter;
	struct msg_data *current_used;
};

struct ast_msg_var_iterator *ast_msg_var_iterator_init(const struct ast_msg *msg)
{
	struct ast_msg_var_iterator *iter;

	iter = ast_calloc(1, sizeof(*iter));
	if (!iter) {
		return NULL;
	}

	iter->iter = ao2_iterator_init(msg->vars, 0);

	return iter;
}

int ast_msg_var_iterator_next(const struct ast_msg *msg, struct ast_msg_var_iterator *iter, const char **name, const char **value)
{
	struct msg_data *data;

	if (!iter) {
		return 0;
	}

	/* Skip any that aren't marked for sending out */
	while ((data = ao2_iterator_next(&iter->iter)) && !data->send) {
		ao2_ref(data, -1);
	}

	if (!data) {
		return 0;
	}

	if (data->send) {
		*name = data->name;
		*value = data->value;
	}

	/* Leave the refcount to be cleaned up by the caller with
	 * ast_msg_var_unref_current after they finish with the pointers to the data */
	iter->current_used = data;

	return 1;
}

void ast_msg_var_unref_current(struct ast_msg_var_iterator *iter)
{
	ao2_cleanup(iter->current_used);
	iter->current_used = NULL;
}

void ast_msg_var_iterator_destroy(struct ast_msg_var_iterator *iter)
{
	if (iter) {
		ao2_iterator_destroy(&iter->iter);
		ast_msg_var_unref_current(iter);
		ast_free(iter);
	}
}

static struct ast_channel *create_msg_q_chan(void)
{
	struct ast_channel *chan;
	struct ast_datastore *ds;

	chan = ast_channel_alloc(1, AST_STATE_UP,
			NULL, NULL, NULL,
			NULL, NULL, NULL, NULL, 0,
			"%s", "Message/ast_msg_queue");

	if (!chan) {
		return NULL;
	}

	ast_channel_tech_set(chan, &msg_chan_tech_hack);
	ast_channel_unlock(chan);
	ast_channel_unlink(chan);

	if (!(ds = ast_datastore_alloc(&msg_datastore, NULL))) {
		ast_hangup(chan);
		return NULL;
	}

	ast_channel_lock(chan);
	ast_channel_datastore_add(chan, ds);
	ast_channel_unlock(chan);

	return chan;
}

/*!
 * \internal
 * \brief Run the dialplan for message processing
 *
 * \pre The message has already been set up on the msg datastore
 *      on this channel.
 */
static void msg_route(struct ast_channel *chan, struct ast_msg *msg)
{
	struct ast_pbx_args pbx_args;

	ast_explicit_goto(chan, msg->context, S_OR(msg->exten, "s"), 1);

	memset(&pbx_args, 0, sizeof(pbx_args));
	pbx_args.no_hangup_chan = 1,
	ast_pbx_run_args(chan, &pbx_args);
}

/*!
 * \internal
 * \brief Clean up ast_channel after each message
 *
 * Reset various bits of state after routing each message so the same ast_channel
 * can just be reused.
 */
static void chan_cleanup(struct ast_channel *chan)
{
	struct ast_datastore *msg_ds, *ds;
	struct varshead *headp;
	struct ast_var_t *vardata;
	struct ast_frame *cur;

	ast_channel_lock(chan);

	/*
	 * Remove the msg datastore.  Free its data but keep around the datastore
	 * object and just reuse it.
	 */
	if ((msg_ds = ast_channel_datastore_find(chan, &msg_datastore, NULL)) && msg_ds->data) {
		ast_channel_datastore_remove(chan, msg_ds);
		ao2_ref(msg_ds->data, -1);
		msg_ds->data = NULL;
	}

	/*
	 * Destroy all other datastores.
	 */
	while ((ds = AST_LIST_REMOVE_HEAD(ast_channel_datastores(chan), entry))) {
		ast_datastore_free(ds);
	}

	/*
	 * Destroy all channel variables.
	 */
	headp = ast_channel_varshead(chan);
	while ((vardata = AST_LIST_REMOVE_HEAD(headp, entries))) {
		ast_var_delete(vardata);
	}

	/*
	 * Remove frames from read queue
	 */
	while ((cur = AST_LIST_REMOVE_HEAD(ast_channel_readq(chan), frame_list))) {
		ast_frfree(cur);
	}

	/*
	 * Restore msg datastore.
	 */
	if (msg_ds) {
		ast_channel_datastore_add(chan, msg_ds);
	}

	/*
	 * Clear softhangup flags.
	 */
	ast_channel_clear_softhangup(chan, AST_SOFTHANGUP_ALL);

	/*
	 * Flush the alert pipe in case we miscounted somewhere when
	 * messing with frames on the read queue, we had to flush the
	 * read queue above, or we had an "Exceptionally long queue
	 * length" event.
	 */
	ast_channel_internal_alert_flush(chan);

	ast_channel_unlock(chan);
}

static void destroy_msg_q_chan(void *data)
{
	struct ast_channel **chan = data;

	if (!*chan) {
		return;
	}

	ast_channel_release(*chan);
}

AST_THREADSTORAGE_CUSTOM(msg_q_chan, NULL, destroy_msg_q_chan);

/*! \internal \brief Handle a message bound for the dialplan */
static int dialplan_handle_msg_cb(struct ast_msg *msg)
{
	struct ast_channel **chan_p, *chan;
	struct ast_datastore *ds;

	if (!(chan_p = ast_threadstorage_get(&msg_q_chan, sizeof(struct ast_channel *)))) {
		return -1;
	}
	if (!*chan_p) {
		if (!(*chan_p = create_msg_q_chan())) {
			return -1;
		}
	}
	chan = *chan_p;

	ast_channel_lock(chan);
	if (!(ds = ast_channel_datastore_find(chan, &msg_datastore, NULL))) {
		ast_channel_unlock(chan);
		return -1;
	}
	ao2_ref(msg, +1);
	ds->data = msg;
	ast_channel_unlock(chan);

	msg_route(chan, msg);
	chan_cleanup(chan);

	return 0;
}

/*! \internal \brief Determine if a message has a destination in the dialplan */
static int dialplan_has_destination_cb(const struct ast_msg *msg)
{
	if (ast_strlen_zero(msg->context)) {
		return 0;
	}

	return ast_exists_extension(NULL, msg->context, S_OR(msg->exten, "s"), 1, NULL);
}

static struct ast_msg_handler dialplan_msg_handler = {
	.name = "dialplan",
	.handle_msg = dialplan_handle_msg_cb,
	.has_destination = dialplan_has_destination_cb,
};

/*!
 * \internal
 * \brief Message queue task processor callback
 *
 * \retval 0 success
 * \retval non-zero failure
 *
 * \note Even though this returns a value, the taskprocessor code ignores the value.
 */
static int msg_q_cb(void *data)
{
	struct ast_msg *msg = data;
	int res = 1;
	int i;

	ast_rwlock_rdlock(&msg_handlers_lock);
	for (i = 0; i < AST_VECTOR_SIZE(&msg_handlers); i++) {
		const struct ast_msg_handler *handler = AST_VECTOR_GET(&msg_handlers, i);

		if (!handler->has_destination(msg)) {
			ast_debug(5, "Handler %s doesn't want message, moving on\n", handler->name);
			continue;
		}

		ast_debug(5, "Dispatching message to %s handler\n", handler->name);
		res &= handler->handle_msg(msg);
	}
	ast_rwlock_unlock(&msg_handlers_lock);

	if (res != 0) {
		ast_log(LOG_WARNING, "No handler processed message from %s to %s\n",
			S_OR(msg->from, "<unknown>"), S_OR(msg->to, "<unknown>"));
	}

	ao2_ref(msg, -1);

	return res;
}

int ast_msg_has_destination(const struct ast_msg *msg)
{
	int i;
	int result = 0;

	ast_rwlock_rdlock(&msg_handlers_lock);
	for (i = 0; i < AST_VECTOR_SIZE(&msg_handlers); i++) {
		const struct ast_msg_handler *handler = AST_VECTOR_GET(&msg_handlers, i);

		ast_debug(5, "Seeing if %s can handle message\n", handler->name);
		if (handler->has_destination(msg)) {
			ast_debug(5, "%s can handle message\n", handler->name);
			result = 1;
			break;
		}
	}
	ast_rwlock_unlock(&msg_handlers_lock);

	return result;
}

int ast_msg_queue(struct ast_msg *msg)
{
	int res;
	res = ast_taskprocessor_push(msg_q_tp, msg_q_cb, msg);
	if (res == -1) {
		ao2_ref(msg, -1);
	}

	return res;
}

/*!
 * \internal
 * \brief Find or create a message datastore on a channel
 *
 * \pre chan is locked
 *
 * \param chan the relevant channel
 *
 * \return the channel's message datastore, or NULL on error
 */
static struct ast_datastore *msg_datastore_find_or_create(struct ast_channel *chan)
{
	struct ast_datastore *ds;

	if ((ds = ast_channel_datastore_find(chan, &msg_datastore, NULL))) {
		return ds;
	}

	if (!(ds = ast_datastore_alloc(&msg_datastore, NULL))) {
		return NULL;
	}

	if (!(ds->data = ast_msg_alloc())) {
		ast_datastore_free(ds);
		return NULL;
	}

	ast_channel_datastore_add(chan, ds);

	return ds;
}

static int msg_func_read(struct ast_channel *chan, const char *function,
		char *data, char *buf, size_t len)
{
	struct ast_datastore *ds;
	struct ast_msg *msg;

	if (!chan) {
		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", function);
		return -1;
	}

	ast_channel_lock(chan);

	if (!(ds = ast_channel_datastore_find(chan, &msg_datastore, NULL))) {
		ast_channel_unlock(chan);
		ast_log(LOG_ERROR, "No MESSAGE data found on the channel to read.\n");
		return -1;
	}

	msg = ds->data;
	ao2_ref(msg, +1);
	ast_channel_unlock(chan);

	ao2_lock(msg);

	if (!strcasecmp(data, "to")) {
		ast_copy_string(buf, msg->to, len);
	} else if (!strcasecmp(data, "from")) {
		ast_copy_string(buf, msg->from, len);
	} else if (!strcasecmp(data, "body")) {
		ast_copy_string(buf, msg->body, len);
	} else {
		ast_log(LOG_WARNING, "Invalid argument to MESSAGE(): '%s'\n", data);
	}

	ao2_unlock(msg);
	ao2_ref(msg, -1);

	return 0;
}

static int msg_func_write(struct ast_channel *chan, const char *function,
		char *data, const char *value)
{
	struct ast_datastore *ds;
	struct ast_msg *msg;

	if (!chan) {
		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", function);
		return -1;
	}

	ast_channel_lock(chan);

	if (!(ds = msg_datastore_find_or_create(chan))) {
		ast_channel_unlock(chan);
		return -1;
	}

	msg = ds->data;
	ao2_ref(msg, +1);
	ast_channel_unlock(chan);

	ao2_lock(msg);

	if (!strcasecmp(data, "to")) {
		ast_msg_set_to(msg, "%s", value);
	} else if (!strcasecmp(data, "from")) {
		ast_msg_set_from(msg, "%s", value);
	} else if (!strcasecmp(data, "body")) {
		ast_msg_set_body(msg, "%s", value);
	} else if (!strcasecmp(data, "custom_data")) {
		int outbound = -1;
		if (!strcasecmp(value, "mark_all_outbound")) {
			outbound = 1;
		} else if (!strcasecmp(value, "clear_all_outbound")) {
			outbound = 0;
		} else {
			ast_log(LOG_WARNING, "'%s' is not a valid value for custom_data\n", value);
		}

		if (outbound != -1) {
			struct msg_data *hdr_data;
			struct ao2_iterator iter = ao2_iterator_init(msg->vars, 0);

			while ((hdr_data = ao2_iterator_next(&iter))) {
				hdr_data->send = outbound;
				ao2_ref(hdr_data, -1);
			}
			ao2_iterator_destroy(&iter);
		}
	} else {
		ast_log(LOG_WARNING, "'%s' is not a valid write argument.\n", data);
	}

	ao2_unlock(msg);
	ao2_ref(msg, -1);

	return 0;
}

static int msg_data_func_read(struct ast_channel *chan, const char *function,
		char *data, char *buf, size_t len)
{
	struct ast_datastore *ds;
	struct ast_msg *msg;
	const char *val;

	if (!chan) {
		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", function);
		return -1;
	}

	ast_channel_lock(chan);

	if (!(ds = ast_channel_datastore_find(chan, &msg_datastore, NULL))) {
		ast_channel_unlock(chan);
		ast_log(LOG_ERROR, "No MESSAGE data found on the channel to read.\n");
		return -1;
	}

	msg = ds->data;
	ao2_ref(msg, +1);
	ast_channel_unlock(chan);

	ao2_lock(msg);

	if ((val = ast_msg_get_var(msg, data))) {
		ast_copy_string(buf, val, len);
	}

	ao2_unlock(msg);
	ao2_ref(msg, -1);

	return 0;
}

static int msg_data_func_write(struct ast_channel *chan, const char *function,
		char *data, const char *value)
{
	struct ast_datastore *ds;
	struct ast_msg *msg;

	if (!chan) {
		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", function);
		return -1;
	}

	ast_channel_lock(chan);

	if (!(ds = msg_datastore_find_or_create(chan))) {
		ast_channel_unlock(chan);
		return -1;
	}

	msg = ds->data;
	ao2_ref(msg, +1);
	ast_channel_unlock(chan);

	ao2_lock(msg);

	ast_msg_set_var_outbound(msg, data, value);

	ao2_unlock(msg);
	ao2_ref(msg, -1);

	return 0;
}

/*!
 * \internal \brief Find a \c ast_msg_tech by its technology name
 *
 * \param tech_name The name of the message technology
 *
 * \note \c msg_techs should be locked via \c msg_techs_lock prior to
 *       calling this function
 *
 * \retval NULL if no \c ast_msg_tech has been registered
 * \retval \c ast_msg_tech if registered
 */
static const struct ast_msg_tech *msg_find_by_tech_name(const char *tech_name)
{
	const struct ast_msg_tech *current;
	int i;

	for (i = 0; i < AST_VECTOR_SIZE(&msg_techs); i++) {
		current = AST_VECTOR_GET(&msg_techs, i);
		if (!strcmp(current->name, tech_name)) {
			return current;
		}
	}

	return NULL;
}

/*!
 * \internal \brief Find a \c ast_msg_handler by its technology name
 *
 * \param tech_name The name of the message technology
 *
 * \note \c msg_handlers should be locked via \c msg_handlers_lock
 *       prior to calling this function
 *
 * \retval NULL if no \c ast_msg_handler has been registered
 * \retval \c ast_msg_handler if registered
 */
static const struct ast_msg_handler *msg_handler_find_by_tech_name(const char *tech_name)
{
	const struct ast_msg_handler *current;
	int i;

	for (i = 0; i < AST_VECTOR_SIZE(&msg_handlers); i++) {
		current = AST_VECTOR_GET(&msg_handlers, i);
		if (!strcmp(current->name, tech_name)) {
			return current;
		}
	}

	return NULL;
}

/*!
 * \internal
 * \brief MessageSend() application
 */
static int msg_send_exec(struct ast_channel *chan, const char *data)
{
	struct ast_datastore *ds;
	struct ast_msg *msg;
	char *tech_name;
	const struct ast_msg_tech *msg_tech;
	char *parse;
	int res = -1;
	AST_DECLARE_APP_ARGS(args,
		AST_APP_ARG(to);
		AST_APP_ARG(from);
	);

	if (ast_strlen_zero(data)) {
		ast_log(LOG_WARNING, "An argument is required to MessageSend()\n");
		pbx_builtin_setvar_helper(chan, "MESSAGE_SEND_STATUS", "INVALID_URI");
		return 0;
	}

	parse = ast_strdupa(data);
	AST_STANDARD_APP_ARGS(args, parse);

	if (ast_strlen_zero(args.to)) {
		ast_log(LOG_WARNING, "A 'to' URI is required for MessageSend()\n");
		pbx_builtin_setvar_helper(chan, "MESSAGE_SEND_STATUS", "INVALID_URI");
		return 0;
	}

	ast_channel_lock(chan);

	if (!(ds = ast_channel_datastore_find(chan, &msg_datastore, NULL))) {
		ast_channel_unlock(chan);
		ast_log(LOG_WARNING, "No message data found on channel to send.\n");
		pbx_builtin_setvar_helper(chan, "MESSAGE_SEND_STATUS", "FAILURE");
		return 0;
	}

	msg = ds->data;
	ao2_ref(msg, +1);
	ast_channel_unlock(chan);

	tech_name = ast_strdupa(args.to);
	tech_name = strsep(&tech_name, ":");

	ast_rwlock_rdlock(&msg_techs_lock);
	msg_tech = msg_find_by_tech_name(tech_name);

	if (!msg_tech) {
		ast_log(LOG_WARNING, "No message technology '%s' found.\n", tech_name);
		pbx_builtin_setvar_helper(chan, "MESSAGE_SEND_STATUS", "INVALID_PROTOCOL");
		goto exit_cleanup;
	}

	/*
	 * The message lock is held here to safely allow the technology
	 * implementation to access the message fields without worrying
	 * that they could change.
	 */
	ao2_lock(msg);
	res = msg_tech->msg_send(msg, S_OR(args.to, ""), S_OR(args.from, ""));
	ao2_unlock(msg);

	pbx_builtin_setvar_helper(chan, "MESSAGE_SEND_STATUS", res ? "FAILURE" : "SUCCESS");

exit_cleanup:
	ast_rwlock_unlock(&msg_techs_lock);
	ao2_ref(msg, -1);

	return 0;
}

static int action_messagesend(struct mansession *s, const struct message *m)
{
	const char *to = ast_strdupa(astman_get_header(m, "To"));
	const char *from = astman_get_header(m, "From");
	const char *body = astman_get_header(m, "Body");
	const char *base64body = astman_get_header(m, "Base64Body");
	char base64decoded[1301] = { 0, };
	char *tech_name = NULL;
	struct ast_variable *vars = NULL;
	struct ast_variable *data = NULL;
	const struct ast_msg_tech *msg_tech;
	struct ast_msg *msg;
	int res = -1;

	if (ast_strlen_zero(to)) {
		astman_send_error(s, m, "No 'To' address specified.");
		return 0;
	}

	if (!ast_strlen_zero(base64body)) {
		ast_base64decode((unsigned char *) base64decoded, base64body, sizeof(base64decoded) - 1);
		body = base64decoded;
	}

	tech_name = ast_strdupa(to);
	tech_name = strsep(&tech_name, ":");

	ast_rwlock_rdlock(&msg_techs_lock);
	msg_tech = msg_find_by_tech_name(tech_name);
	if (!msg_tech) {
		ast_rwlock_unlock(&msg_techs_lock);
		astman_send_error(s, m, "Message technology not found.");
		return 0;
	}

	if (!(msg = ast_msg_alloc())) {
		ast_rwlock_unlock(&msg_techs_lock);
		astman_send_error(s, m, "Internal failure\n");
		return 0;
	}

	data = astman_get_variables_order(m, ORDER_NATURAL);
	for (vars = data; vars; vars = vars->next) {
		ast_msg_set_var_outbound(msg, vars->name, vars->value);
	}

	ast_msg_set_body(msg, "%s", body);

	res = msg_tech->msg_send(msg, S_OR(to, ""), S_OR(from, ""));

	ast_rwlock_unlock(&msg_techs_lock);

	ast_variables_destroy(vars);
	ao2_ref(msg, -1);

	if (res) {
		astman_send_error(s, m, "Message failed to send.");
	} else {
		astman_send_ack(s, m, "Message successfully sent");
	}
	return 0;
}

int ast_msg_send(struct ast_msg *msg, const char *to, const char *from)
{
	char *tech_name = NULL;
	const struct ast_msg_tech *msg_tech;
	int res = -1;

	if (ast_strlen_zero(to)) {
		ao2_ref(msg, -1);
		return -1;
	}

	tech_name = ast_strdupa(to);
	tech_name = strsep(&tech_name, ":");

	ast_rwlock_rdlock(&msg_techs_lock);
	msg_tech = msg_find_by_tech_name(tech_name);

	if (!msg_tech) {
		ast_log(LOG_ERROR, "Unknown message tech: %s\n", tech_name);
		ast_rwlock_unlock(&msg_techs_lock);
		return -1;
	}

	res = msg_tech->msg_send(msg, S_OR(to, ""), S_OR(from, ""));

	ast_rwlock_unlock(&msg_techs_lock);

	ao2_ref(msg, -1);

	return res;
}

/*!
 * \brief Structure used to transport a message through the frame core
 * \since 13.22.0
 * \since 15.5.0
 */
struct ast_msg_data {
	/*! The length of this structure plus the actual length of the allocated buffer */
	size_t length;
	enum ast_msg_data_source_type source;
	/*! These are indices into the buffer where teh attribute starts */
	int attribute_value_offsets[__AST_MSG_DATA_ATTR_LAST];
	/*! The buffer containing the NULL separated attributes */
	char buf[0];
};

#define ATTRIBUTE_UNSET -1

struct ast_msg_data *ast_msg_data_alloc(enum ast_msg_data_source_type source,
	struct ast_msg_data_attribute attributes[], size_t count)
{
	struct ast_msg_data *msg;
	size_t len = sizeof(*msg);
	size_t i;
	size_t current_offset = 0;
	enum ast_msg_data_attribute_type attr_type;

	if (!attributes) {
		ast_assert(attributes != NULL);
		return NULL;
	}

	if (!count) {
		ast_assert(count > 0);
		return NULL;
	}

	/* Calculate the length required for the buffer */
	for (i=0; i < count; i++) {
		if (!attributes[i].value) {
			ast_assert(attributes[i].value != NULL);
			return NULL;
		}
		len += (strlen(attributes[i].value) + 1);
	}

	msg = ast_calloc(1, len);
	if (!msg) {
		return NULL;
	}
	msg->source = source;
	msg->length = len;

	/* Mark all of the attributes as unset */
	for (attr_type = 0; attr_type < __AST_MSG_DATA_ATTR_LAST; attr_type++) {
		msg->attribute_value_offsets[attr_type] = ATTRIBUTE_UNSET;
	}

	/* Set the ones we have and increment the offset */
	for (i=0; i < count; i++) {
		len = (strlen(attributes[i].value) + 1);
		strcpy(msg->buf + current_offset, attributes[i].value); /* Safe */
		msg->attribute_value_offsets[attributes[i].type] = current_offset;
		current_offset += len;
	}

	return msg;
}

struct ast_msg_data *ast_msg_data_dup(struct ast_msg_data *msg)
{
	struct ast_msg_data *dest;

	if (!msg) {
		ast_assert(msg != NULL);
		return NULL;
	}

	dest = ast_malloc(msg->length);
	if (!dest) {
		return NULL;
	}
	memcpy(dest, msg, msg->length);

	return dest;
}

size_t ast_msg_data_get_length(struct ast_msg_data *msg)
{
	if (!msg) {
		ast_assert(msg != NULL);
		return 0;
	}

	return msg->length;
}

enum ast_msg_data_source_type ast_msg_data_get_source_type(struct ast_msg_data *msg)
{
	if (!msg) {
		ast_assert(msg != NULL);
		return AST_MSG_DATA_SOURCE_TYPE_UNKNOWN;
	}

	return msg->source;
}

const char *ast_msg_data_get_attribute(struct ast_msg_data *msg,
	enum ast_msg_data_attribute_type attribute_type)
{
	if (!msg) {
		ast_assert(msg != NULL);
		return "";
	}

	if (msg->attribute_value_offsets[attribute_type] > ATTRIBUTE_UNSET) {
		return msg->buf + msg->attribute_value_offsets[attribute_type];
	}

	return "";
}

int ast_msg_data_queue_frame(struct ast_channel *channel, struct ast_msg_data *msg)
{
	struct ast_frame f;

	if (!channel) {
		ast_assert(channel != NULL);
		return -1;
	}

	if (!msg) {
		ast_assert(msg != NULL);
		return -1;
	}

	memset(&f, 0, sizeof(f));
	f.frametype = AST_FRAME_TEXT_DATA;
	f.data.ptr = msg;
	f.datalen = msg->length;
	return ast_queue_frame(channel, &f);
}

int ast_msg_tech_register(const struct ast_msg_tech *tech)
{
	const struct ast_msg_tech *match;

	ast_rwlock_wrlock(&msg_techs_lock);

	match = msg_find_by_tech_name(tech->name);
	if (match) {
		ast_log(LOG_ERROR, "Message technology already registered for '%s'\n",
		        tech->name);
		ast_rwlock_unlock(&msg_techs_lock);
		return -1;
	}

	if (AST_VECTOR_APPEND(&msg_techs, tech)) {
		ast_log(LOG_ERROR, "Failed to register message technology for '%s'\n",
		        tech->name);
		ast_rwlock_unlock(&msg_techs_lock);
		return -1;
	}
	ast_verb(3, "Message technology '%s' registered.\n", tech->name);

	ast_rwlock_unlock(&msg_techs_lock);

	return 0;
}

/*!
 * \brief Comparison callback for \c ast_msg_tech vector removal
 *
 * \param vec_elem The element in the vector being compared
 * \param srch The element being looked up
 *
 * \retval non-zero The items are equal
 * \retval 0 The items are not equal
 */
static int msg_tech_cmp(const struct ast_msg_tech *vec_elem, const struct ast_msg_tech *srch)
{
	return !strcmp(vec_elem->name, srch->name);
}

int ast_msg_tech_unregister(const struct ast_msg_tech *tech)
{
	int match;

	ast_rwlock_wrlock(&msg_techs_lock);
	match = AST_VECTOR_REMOVE_CMP_UNORDERED(&msg_techs, tech, msg_tech_cmp,
	                                        AST_VECTOR_ELEM_CLEANUP_NOOP);
	ast_rwlock_unlock(&msg_techs_lock);

	if (match) {
		ast_log(LOG_ERROR, "No '%s' message technology found.\n", tech->name);
		return -1;
	}

	ast_verb(2, "Message technology '%s' unregistered.\n", tech->name);

	return 0;
}

int ast_msg_handler_register(const struct ast_msg_handler *handler)
{
	const struct ast_msg_handler *match;

	ast_rwlock_wrlock(&msg_handlers_lock);

	match = msg_handler_find_by_tech_name(handler->name);
	if (match) {
		ast_log(LOG_ERROR, "Message handler already registered for '%s'\n",
		        handler->name);
		ast_rwlock_unlock(&msg_handlers_lock);
		return -1;
	}

	if (AST_VECTOR_APPEND(&msg_handlers, handler)) {
		ast_log(LOG_ERROR, "Failed to register message handler for '%s'\n",
		        handler->name);
		ast_rwlock_unlock(&msg_handlers_lock);
		return -1;
	}
	ast_verb(2, "Message handler '%s' registered.\n", handler->name);

	ast_rwlock_unlock(&msg_handlers_lock);

	return 0;

}

/*!
 * \brief Comparison callback for \c ast_msg_handler vector removal
 *
 * \param vec_elem The element in the vector being compared
 * \param srch The element being looked up
 *
 * \retval non-zero The items are equal
 * \retval 0 The items are not equal
 */
static int msg_handler_cmp(const struct ast_msg_handler *vec_elem, const struct ast_msg_handler *srch)
{
	return !strcmp(vec_elem->name, srch->name);
}

int ast_msg_handler_unregister(const struct ast_msg_handler *handler)
{
	int match;

	ast_rwlock_wrlock(&msg_handlers_lock);
	match = AST_VECTOR_REMOVE_CMP_UNORDERED(&msg_handlers, handler, msg_handler_cmp,
	                                        AST_VECTOR_ELEM_CLEANUP_NOOP);
	ast_rwlock_unlock(&msg_handlers_lock);

	if (match) {
		ast_log(LOG_ERROR, "No '%s' message handler found.\n", handler->name);
		return -1;
	}

	ast_verb(3, "Message handler '%s' unregistered.\n", handler->name);
	return 0;
}

void ast_msg_shutdown(void)
{
	if (msg_q_tp) {
		msg_q_tp = ast_taskprocessor_unreference(msg_q_tp);
	}
}

/*!
 * \internal
 * \brief Clean up other resources on Asterisk shutdown
 *
 * \note This does not include the msg_q_tp object, which must be disposed
 * of prior to Asterisk checking for channel destruction in its shutdown
 * sequence.  The atexit handlers are executed after this occurs.
 */
static void message_shutdown(void)
{
	ast_msg_handler_unregister(&dialplan_msg_handler);

	ast_custom_function_unregister(&msg_function);
	ast_custom_function_unregister(&msg_data_function);
	ast_unregister_application(app_msg_send);
	ast_manager_unregister("MessageSend");

	AST_VECTOR_FREE(&msg_techs);
	ast_rwlock_destroy(&msg_techs_lock);

	AST_VECTOR_FREE(&msg_handlers);
	ast_rwlock_destroy(&msg_handlers_lock);
}

/*
 * \internal
 * \brief Initialize stuff during Asterisk startup.
 *
 * Cleanup isn't a big deal in this function.  If we return non-zero,
 * Asterisk is going to exit.
 *
 * \retval 0 success
 * \retval non-zero failure
 */
int ast_msg_init(void)
{
	int res;

	msg_q_tp = ast_taskprocessor_get("ast_msg_queue", TPS_REF_DEFAULT);
	if (!msg_q_tp) {
		return -1;
	}

	ast_rwlock_init(&msg_techs_lock);
	if (AST_VECTOR_INIT(&msg_techs, 8)) {
		return -1;
	}

	ast_rwlock_init(&msg_handlers_lock);
	if (AST_VECTOR_INIT(&msg_handlers, 4)) {
		return -1;
	}

	res = ast_msg_handler_register(&dialplan_msg_handler);

	res |= __ast_custom_function_register(&msg_function, NULL);
	res |= __ast_custom_function_register(&msg_data_function, NULL);
	res |= ast_register_application2(app_msg_send, msg_send_exec, NULL, NULL, NULL);
	res |= ast_manager_register_xml_core("MessageSend", EVENT_FLAG_MESSAGE, action_messagesend);

	ast_register_cleanup(message_shutdown);

	return res;
}