This file is indexed.

/usr/include/sipxtapi/tapi/sipXtapiEvents.h is in libsipxtapi-dev 3.3.0~test17-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   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
//  
// Copyright (C) 2007 Robert J. Andreasen, Jr.
// Licensed to SIPfoundry under a Contributor Agreement. 
//
// Copyright (C) 2006 SIPez LLC. 
// Licensed to SIPfoundry under a Contributor Agreement. 
//
// Copyright (C) 2004-2006 SIPfoundry Inc.
// Licensed by SIPfoundry under the LGPL license.
//
// Copyright (C) 2004-2006 Pingtel Corp.  All rights reserved.
// Licensed to SIPfoundry under a Contributor Agreement.
//
// $$
///////////////////////////////////////////////////////////////////////////////


/**
 * @file sipXtapiEvents.h
 * sipXtapi event declarations
 *
 * The sipXtapiEvents.h header file defines all of the events fired as part of
 * sipXtapi.  Event categories include call state events, line state events,
 * SIP info events, SIP subscription events, configuration events, security
 * events, media events, and keepalive events.
 *
 * Each event notification is comprised of a event type and a cause code.
 * The event type identifies a state transition (e.g. from call connected to
 * call disconnected.  The cause identifies the reason for the change (e.g.
 * someone hung up).
 *
 * @see sipxEventListenerAdd
 * @see sipxEventListenerRemove
 * @see SIPX_EVENT_CALLBACK_PROC
 * @see SIPX_EVENT_CATEGORY
 */

#ifndef _SIPXTAPIEVENT_H
#define _SIPXTAPIEVENT_H

// SYSTEM INCLUDES
// APPLICATION INCLUDES
#include "sipXtapi.h"

// DEFINES
// MACROS
// EXTERNAL FUNCTIONS
// EXTERNAL VARIABLES
// CONSTANTS
// FORWARD DECLARATIONS

/**
 * Enum with all of the possible event types.
 */
typedef enum SIPX_EVENT_CATEGORY
{
    EVENT_CATEGORY_CALLSTATE,       /**< CALLSTATE events signify a change in state of a 
                                         call.  States range from the notification of a 
                                         new call to ringing to connection established to 
                                         changes in audio state (starting sending, stop 
                                         sending) to termination of a call. */
    EVENT_CATEGORY_LINESTATE,       /**< LINESTATE events indicate changes in the status 
                                         of a line appearance.  Lines identify inbound 
                                         and outbound identities and can be either 
                                         provisioned (hardcoded) or configured to 
                                         automatically register with a registrar.  
                                         Lines also encapsulate the authentication 
                                         criteria needed for dynamic registrations. */
    EVENT_CATEGORY_INFO_STATUS,     /**< INFO_STATUS events are sent when the application 
                                         requests sipXtapi to send an INFO message to 
                                         another user agent.  The status event includes 
                                         the response for the INFO method.  Application 
                                         developers should look at this event to determine 
                                         the outcome of the INFO message. */
    EVENT_CATEGORY_INFO,            /**< INFO events are sent to the application whenever 
                                         an INFO message is received by the sipXtapi user 
                                         agent.  INFO messages are sent to a specific call.
                                         sipXtapi will automatically acknowledges the INFO 
                                         message at the protocol layer. */
    EVENT_CATEGORY_SUB_STATUS,      /**< SUB_STATUS events are sent to the application 
                                         layer for information on the subscription state
                                         (e.g. OK, Expired). */                                    
    EVENT_CATEGORY_NOTIFY,          /**< NOTIFY evens are send to the application layer
                                         after a remote publisher has sent data to the 
                                         application.  The application layer can retrieve
                                         the data from this event. */
    EVENT_CATEGORY_CONFIG,          /**< CONFIG events signify changes in configuration.
                                         For example, when requesting STUN support, a 
                                         notification is sent with the STUN outcome (either
                                         SUCCESS or FAILURE) */
    EVENT_CATEGORY_SECURITY,        /**< SECURITY events signify occurences in call security 
                                         processing.  These events are only sent when using
                                         S/MIME or TLS. */
    EVENT_CATEGORY_MEDIA,           /**< MEDIA events signify changes in the audio state for
                                         sipXtapi or a particular call. */
    EVENT_CATEGORY_KEEPALIVE        /**< KEEPALIVE events signal when a keepalive is 
                                         started/stopped/fails.  A feedback event will
                                         report back your NAT-mapped IP address in some 
                                         cases.  @see SIPX_KEEPALIVE_TYPE for more 
                                         information.*/

                                         
} SIPX_EVENT_CATEGORY;

/**
 * VALID_SIPX_EVENT_CATEGORY utility macro to validate if an event category
 * is valid (within expected range).
 */
#define VALID_SIPX_EVENT_CATEGORY(x) (((x) >= EVENT_CATEGORY_CALLSTATE) && ((x) <= EVENT_CATEGORY_KEEPALIVE))

/**
 * Signature for event callback/observer.  Application developers should
 * not block this event callback thread -- You should re-post these events
 * to your own thread context for handling if you require blocking and/or 
 * heavy prorcessing.  The sipxDuplicateEvent and sipxFreeDuplicatedEvent 
 * methods are available to copy the event callback data (The data is only 
 * available for the duration of the callback).  For example, upon receiving 
 * the callback, copy the data using sipxDuplicateEvent(...), post the 
 * copied data to your event callback, process it, and lastly free the event 
 * data using sipxFreeDuplicatedEvent(...).
 *
 * The application developer must look at the SIPX_EVENT_CATEGORY and then 
 * cast the pInfo method to the appropriate structure:
 *
 * <pre>
 * EVENT_CATEGORY_CALLSTATE:   pCallInfo = (SIPX_CALLSTATE_INFO*) pInfo ;
 * EVENT_CATEGORY_LINESTATE:   pLineInfo = (SIPX_LINESTATE_INFO*) pInfo ;
 * EVENT_CATEGORY_INFO_STATUS: pInfoStatus = (SIPX_INFOSTATUS_INFO*) pInfo ;
 * EVENT_CATEGORY_INFO:        pInfoInfo = (SIPX_INFO_INFO*) pInfo ;
 * EVENT_CATEGORY_SUB_STATUS:  pSubInfo = (SIPX_SUBSTATUS_INFO*) pInfo ;
 * EVENT_CATEGORY_NOTIFY:      pNotifyInfo = (SIPX_NOTIFY_INFO*) pInfo ;
 * EVENT_CATEGORY_CONFIG:      pConfigInfo - (SIPX_CONFIG_INFO*) pInfo ;
 * EVENT_CATEGORY_SECURITY:    pSecInfo = (SIPX_SECURITY_INFO*) pInfo ;
 * EVENT_CATEGORY_MEDIA:       pMediaInfo = (SIPX_MEDIA_INFO*) pInfo ;
 * </pre>
 *
 * Please see the SIPX_EVENT_CATEGORY and structure definitions for details.
 *
 * @param category The category of the event (call, line, subscription, 
          notify, etc.).
 * @param pInfo Pointer to the event info structure.  Depending on the event 
 *        type, the application layer needs to cast this parameter to the 
 *        appropriate structure.
 * @param pUserData User data provided when listener was added
 */
typedef bool (SIPX_CALLING_CONVENTION *SIPX_EVENT_CALLBACK_PROC)(SIPX_EVENT_CATEGORY category, 
                                                                 void* pInfo, 
                                                                 void* pUserData);
/**
 * Major call state events identify significant changes in the state of a 
 * call.
 *
 * Below you will find state diagrams that show the typical event transitions
 * for both outbound and inbound calls.
 *
 * @image html callevents_inbound.gif
 *
 * Figure 1: Event flows for an inbound call (received call)
 *
 * @image html callevents_outbound.gif
 *
 * Figure 2: Event flows for an outbound call (placed call)
 */
typedef enum SIPX_CALLSTATE_EVENT
{
   CALLSTATE_UNKNOWN         = 0,    /**< An UNKNOWN event is generated when the state for a call 
                                       is no longer known.  This is generally an error 
                                       condition; see the minor event for specific causes. */
   CALLSTATE_NEWCALL         = 1000, /**< The NEWCALL event indicates that a new call has been 
                                       created automatically by the sipXtapi.  This event is 
                                       most frequently generated in response to an inbound 
                                       call request.  */
   CALLSTATE_DIALTONE        = 2000, /**< The DIALTONE event indicates that a new call has been 
                                       created for the purpose of placing an outbound call.  
                                       The application layer should determine if it needs to 
                                       simulate dial tone for the end user. */
   CALLSTATE_REMOTE_OFFERING = 2500, /**< The REMOTE_OFFERING event indicates that a call setup 
                                       invitation has been sent to the remote party.  The 
                                       invitation may or may not every receive a response.  If
                                       a response is not received in a timely manor, sipXtapi 
                                       will move the call into a disconnected state.  If 
                                       calling another sipXtapi user agent, the reciprocal 
                                       state is OFFER. */
   CALLSTATE_REMOTE_ALERTING = 3000, /**< The REMOTE_ALERTING event indicates that a call setup 
                                       invitation has been accepted and the end user is in the
                                       alerting state (ringing).  Depending on the SIP 
                                       configuration, end points, and proxy servers involved, 
                                       this event should only last for 3 minutes.  Afterwards,
                                       the state will automatically move to DISCONNECTED.  If 
                                       calling another sipXtapi user agent, the reciprocate 
                                       state is ALERTING. 
                                    
                                       Pay attention to the cause code for this event.  If
                                       the cause code is "CALLSTATE_CAUSE_EARLY_MEDIA", the 
                                       remote the party is sending early media (e.g. gateway is
                                       producing ringback or audio feedback).  In this case, the
                                       user agent should not produce local ringback. */
   CALLSTATE_CONNECTED       = 4000, /**< The CONNECTED state indicates that call has been setup 
                                       between the local and remote party.  Network audio should be 
                                       flowing provided and the microphone and speakers should
                                       be engaged. */
   CALLSTATE_BRIDGED         = 5000, /** The BRIDGED state indicates that a call is active,
                                       however, the local microphone/speaker are not engaged.  If
                                       this call is part of a conference, the party will be able
                                       to talk with other BRIDGED conference parties.  Application
                                       developers can still play and record media. */
   CALLSTATE_HELD            = 6000, /** The HELD state indicates that a call is
                                       both locally and remotely held.  No network audio is flowing 
                                       and the local microphone and speaker are not engaged. */
   CALLSTATE_REMOTE_HELD     = 7000, /** The REMOTE_HELD state indicates that the remote 
                                       party is on hold.  Locally, the microphone and speaker are
                                       still engaged, however, no network audio is flowing. */

   CALLSTATE_DISCONNECTED    = 8000, /**< The DISCONNECTED state indicates that a call was 
                                       disconnected or failed to connect.  A call may move 
                                       into the DISCONNECTED states from almost every other 
                                       state.  Please review the DISCONNECTED minor events to
                                       understand the cause. */
   CALLSTATE_OFFERING        = 9000, /**< An OFFERING state indicates that a new call invitation 
                                       has been extended this user agent.  Application 
                                       developers should invoke sipxCallAccept(), 
                                       sipxCallReject() or sipxCallRedirect() in response.  
                                       Not responding will result in an implicit call 
                                       sipXcallReject(). */                                
   CALLSTATE_ALERTING        = 10000, /**< An ALERTING state indicates that an inbound call has 
                                       been accepted and the application layer should alert 
                                       the end user.  The alerting state is limited to 3 
                                       minutes in most configurations; afterwards the call 
                                       will be canceled.  Applications will generally play 
                                       some sort of ringing tone in response to this event. */
   CALLSTATE_DESTROYED       = 11000, /**< The DESTORYED event indicates the underlying resources 
                                       have been removed for a call.  This is the last event 
                                       that the application will receive for any call.  The 
                                       call handle is invalid after this event is received. */
   CALLSTATE_TRANSFER_EVENT   = 12000, /**< The transfer state indicates a state change in a 
                                       transfer attempt.  Please see the CALLSTATE_TRANSFER_EVENT cause 
                                       codes for details on each state transition */
} SIPX_CALLSTATE_EVENT;

 
/**
 * Callstate cause events identify the reason for a Callstate event or 
 * provide more detail.
 */
typedef enum SIPX_CALLSTATE_CAUSE
{
   CALLSTATE_CAUSE_UNKNOWN,        /**< Unknown cause */
   CALLSTATE_CAUSE_NORMAL,         /**< The stage changed due to normal operation */
   CALLSTATE_CAUSE_TRANSFERRED,	  /**< A call is being transferred to this user 
                                        agent from another user agent.*/
   CALLSTATE_CAUSE_TRANSFER,	     /**< A call on this user agent is being transferred 
                                        to another user agent. */                                     
   CALLSTATE_CAUSE_CONFERENCE,     /**< A conference operation caused a stage change */
   CALLSTATE_CAUSE_EARLY_MEDIA,    /**< The remote party is alerting and providing 
                                        ringback audio (early media) */

   CALLSTATE_CAUSE_REQUEST_NOT_ACCEPTED, 
                                   /**< The callee rejected a request (e.g. hold) */
   CALLSTATE_CAUSE_BAD_ADDRESS,    /**< The state changed due to a bad address.  This 
                                        can be caused by a malformed URL or network
                                        problems with your DNS server */
   CALLSTATE_CAUSE_BUSY,           /**< The state changed because the remote party is
                                        busy */
   CALLSTATE_CAUSE_RESOURCE_LIMIT, /**< Not enough resources are available to complete
                                        the desired operation */
   CALLSTATE_CAUSE_NETWORK,        /**< A network error caused the desired operation to 
                                        fail */
   CALLSTATE_CAUSE_REDIRECTED,     /**< The stage changed due to a redirection of a call. */
   CALLSTATE_CAUSE_NO_RESPONSE,    /**< No response was received from the remote party or 
                                        network node. */
   CALLSTATE_CAUSE_AUTH,           /**< Unable to authenticate due to either bad or 
                                        missing credentials */
   CALLSTATE_CAUSE_TRANSFER_INITIATED,  
                                /**< A transfer attempt has been initiated.  This event
                                     is sent when a user agent attempts either a blind
                                     or consultative transfer. */
   CALLSTATE_CAUSE_TRANSFER_ACCEPTED,  
                                /**< A transfer attempt has been accepted by the remote
                                     transferee.  This event indicates that the 
                                     transferee supports transfers (REFER method).  The
                                     event is fired upon a 2xx class response to the SIP
                                     REFER request. */
   CALLSTATE_CAUSE_TRANSFER_TRYING,
                                /**< The transfer target is attempting the transfer.  
                                     This event is sent when transfer target (or proxy /
                                     B2BUA) receives the call invitation, but before the
                                     the tranfer target accepts is. */
   CALLSTATE_CAUSE_TRANSFER_RINGING,   
                                /**< The transfer target is ringing.  This event is 
                                     generally only sent during blind transfer.  
                                     Consultative transfer should proceed directly to 
                                     TRANSFER_SUCCESS or TRANSFER_FAILURE. */
   CALLSTATE_CAUSE_TRANSFER_SUCCESS,
                                /**< The transfer was completed successfully.  The
                                     original call to transfer target will
                                     automatically disconnect.*/
   CALLSTATE_CAUSE_TRANSFER_FAILURE,
                                /**< The transfer failed.  After a transfer fails,
                                     the application layer is responsible for 
                                     recovering original call to the transferee. 
                                     That call is left on hold. */
   CALLSTATE_CAUSE_REMOTE_SMIME_UNSUPPORTED,
                                /**< Fired if the remote party's user-agent does not
                                     support S/MIME. */
   CALLSTATE_CAUSE_SMIME_FAILURE,
                                /**< Fired if a local S/MIME operation failed. 
                                     For more information, applications should 
                                     process the SECURITY event. */
   CALLSTATE_CAUSE_SHUTDOWN,      /**< The even was fired as part of sipXtapi 
                                       shutdown. */
   CALLSTATE_CAUSE_BAD_REFER,     /**< An unusable refer was sent to this user-agent. */    
   CALLSTATE_CAUSE_NO_KNOWN_INVITE, /**< This user-agent received a request or response, 
                                         but there is no known matching invite. */  
   CALLSTATE_CAUSE_BYE_DURING_IDLE, /**< A BYE message was received, however, the call is in
                                         in an idle state. */       
   CALLSTATE_CAUSE_UNKNOWN_STATUS_CODE, /**< A response was received with an unknown status code. */
   CALLSTATE_CAUSE_BAD_REDIRECT,    /**< Receive a redirect with NO contact or a RANDOM redirect. */
   CALLSTATE_CAUSE_TRANSACTION_DOES_NOT_EXIST, /**< No such transaction;  Accepting or Rejecting a call that
                                                    is part of a transfer. */
   CALLSTATE_CAUSE_CANCEL,        /**< The event was fired in response to a cancel
                                       attempt from the remote party */
   CALLSTATE_CAUSE_NO_CODECS,     /**< An attempt to send INVITE with no codecs in SDP.*/
   CALLSTATE_CAUSE_SERVER_ERROR   /**< Server or client at far end had major (500 class) error */
} SIPX_CALLSTATE_CAUSE ;

/**
 * Enumeration of possible linestate Events.
 *
 * @image html lineevents.gif
 */
 typedef enum SIPX_LINESTATE_EVENT
{
    LINESTATE_UNKNOWN         = 0,        /**< This is the initial Line event state. */
    LINESTATE_REGISTERING     = 20000,    /**< The REGISTERING event is fired when sipXtapi
                                               has successfully sent a REGISTER message,
                                               but has not yet received a success response from the
                                               registrar server */    
    LINESTATE_REGISTERED      = 21000,    /**< The REGISTERED event is fired after sipXtapi has received
                                               a response from the registrar server, indicating a successful
                                               registration. */
    LINESTATE_UNREGISTERING   = 22000,    /**< The UNREGISTERING event is fired when sipXtapi
                                               has successfully sent a REGISTER message with an expires=0 parameter,
                                               but has not yet received a success response from the
                                               registrar server */
    LINESTATE_UNREGISTERED    = 23000,    /**< The UNREGISTERED event is fired after sipXtapi has received
                                               a response from the registrar server, indicating a successful
                                               un-registration. */
    LINESTATE_REGISTER_FAILED = 24000,    /**< The REGISTER_FAILED event is fired to indicate a failure of REGISTRATION.
                                               It is fired in the following cases:  
                                               The client could not connect to the registrar server.
                                               The registrar server challenged the client for authentication credentials,
                                               and the client failed to supply valid credentials.
                                               The registrar server did not generate a success response (status code == 200)
                                               within a timeout period.  */
    LINESTATE_UNREGISTER_FAILED  = 25000, /**< The UNREGISTER_FAILED event is fired to indicate a failure of un-REGISTRATION.
                                               It is fired in the following cases:  
                                               The client could not connect to the registrar server.
                                               The registrar server challenged the client for authentication credentials,
                                               and the client failed to supply valid credentials.
                                               The registrar server did not generate a success response (status code == 200)
                                               within a timeout period.  */
    LINESTATE_PROVISIONED      = 26000,   /**< The PROVISIONED event is fired when a sipXtapi Line is added, and Registration is not 
                                               requested (i.e. - sipxLineAdd is called with a bRegister parameter of false. */ 
} SIPX_LINESTATE_EVENT;  


/**
 * Enumeration of possible linestate Event causes.
 */
typedef enum SIPX_LINESTATE_CAUSE
{
    LINESTATE_CAUSE_UNKNOWN                           = 0,                                 /**< No cause specified. */
    LINESTATE_REGISTERING_NORMAL                      = LINESTATE_REGISTERING + 1,         /**< See LINESTATE_REGISTERING
                                                                                                event. */ 
    LINESTATE_REGISTERED_NORMAL                       = LINESTATE_REGISTERED + 1,          /**< See LINESTATE_REGISTERED
                                                                                                event. */
    LINESTATE_UNREGISTERING_NORMAL                    = LINESTATE_UNREGISTERING + 1,       /**< See LINESTATE_UNREGISTERING
                                                                                                event. */
    LINESTATE_UNREGISTERED_NORMAL                     = LINESTATE_UNREGISTERED + 1,        /**< See LINESTATE_UNREGISTERED
                                                                                                event. */
    LINESTATE_REGISTER_FAILED_COULD_NOT_CONNECT       = LINESTATE_REGISTER_FAILED + 1,     /**< Failed to register because
                                                                                                of a connectivity problem. */
    LINESTATE_REGISTER_FAILED_NOT_AUTHORIZED          = LINESTATE_REGISTER_FAILED + 2,     /**< Failed to register because
                                                                                                of an authorization / 
                                                                                                authentication failure. */
    LINESTATE_REGISTER_FAILED_TIMEOUT                 = LINESTATE_REGISTER_FAILED + 3,     /**< Failed to register because of
                                                                                                a timeout. */
    LINESTATE_UNREGISTER_FAILED_COULD_NOT_CONNECT     = LINESTATE_UNREGISTER_FAILED + 1,   /**< Failed to unregister because of
                                                                                                a connectivity problem. */
    LINESTATE_UNREGISTER_FAILED_NOT_AUTHORIZED        = LINESTATE_UNREGISTER_FAILED + 2,   /**< Failed to unregister because of
                                                                                                of an authorization / 
                                                                                                authentication failure. */
    LINESTATE_UNREGISTER_FAILED_TIMEOUT               = LINESTATE_UNREGISTER_FAILED + 3,   /**< Failed to register because of
                                                                                                a timeout. */
    LINESTATE_PROVISIONED_NORMAL                      = LINESTATE_PROVISIONED + 1          /**< See LINESTATE_PROVISIONED
                                                                                                event. */
} SIPX_LINESTATE_CAUSE;




/**
 * Enumeration of possible INFO status events
 */
enum SIPX_INFOSTATUS_EVENT
{
    INFOSTATUS_UNKNOWN       = 0 ,     /**< This is the initial value for an INFOSTATUS event. */
    INFOSTATUS_RESPONSE      = 30000,  /**< This event is fired if a response is received after an
                                            INFO message has been sent */
    INFOSTATUS_NETWORK_ERROR = 31000   /**< This event is fired in case a network error was encountered
                                            while trying to send an INFO event. */
};


/**
 * Enumeration of possible configuration events
 */
enum SIPX_CONFIG_EVENT
{
    CONFIG_UNKNOWN = 0,           /**< Unknown configuration event */
    CONFIG_STUN_SUCCESS  = 40000, /**< A STUN binding has been obtained for signaling purposes.
                                       For a SIPX_CONFIG_EVENT type of CONFIG_STUN_SUCCESS, 
                                       the pData pointer of the info structure will point to a
                                       SIPX_CONTACT_ADDRESS structure. */
    CONFIG_STUN_FAILURE  = 41000, /**< Unable to obtain a STUN binding for signaling purposes. */
} ;


/**
 * Enumeration of possible security events
 */
typedef enum SIPX_SECURITY_EVENT
{
    SECURITY_UNKNOWN       = 0,/**< An UNKNOWN event is generated when the state for a call 
                                 is no longer known.  This is generally an error 
                                 condition; see the minor event for specific causes. */
    SECURITY_ENCRYPT = 1000, /**< The ENCRYPT event indicates that an SMIME encryption has been
                                  attempted.  See the cause code for the encryption outcome,
                                  and the info structure for more information. */
    SECURITY_DECRYPT = 2000, /**< The DECRYPT event indicates that an SMIME decryption has been
                                  attempted.  See the cause code for the encryption outcome,
                                  and the info structure for more information. */
    SECURITY_TLS              = 4000, /**< TLS related security event. */
} SIPX_SECURITY_EVENT;

/**
 * Enumeration of possible security causes
 */
typedef enum SIPX_SECURITY_CAUSE
{
    SECURITY_CAUSE_UNKNOWN = 0,                      /**< An UNKNOWN cause code is generated when the state
                                                          for the security operation 
                                                          is no longer known.  This is generally an error 
                                                          condition; see the info structure for details. */
    SECURITY_CAUSE_NORMAL,                           /**< Event was fired as part of the normal encryption / decryption process. */
    SECURITY_CAUSE_ENCRYPT_SUCCESS,                  /**< An S/MIME encryption succeeded. */
    SECURITY_CAUSE_ENCRYPT_FAILURE_LIB_INIT,         /**< An S/MIME encryption failed because the
                                                          security library could not start. */
    SECURITY_CAUSE_ENCRYPT_FAILURE_BAD_PUBLIC_KEY,   /**< An S/MIME encryption failed because of a bad certificate / public key. */
    SECURITY_CAUSE_ENCRYPT_FAILURE_INVALID_PARAMETER,/**< An S/MIME encryption failed because of an invalid parameter. */
    SECURITY_CAUSE_DECRYPT_SUCCESS,                  /**< An S/MIME decryption succeeded. */ 
    SECURITY_CAUSE_DECRYPT_FAILURE_DB_INIT,          /**< An S/MIME decryption failed due to a failure to initialize the certificate database. */
    SECURITY_CAUSE_DECRYPT_FAILURE_BAD_DB_PASSWORD,  /**< An S/MIME decryption failed due to an invalid certificate database password. */
    SECURITY_CAUSE_DECRYPT_FAILURE_INVALID_PARAMETER,/**< An S/MIME decryption failed due to an invalid parameter. */
    SECURITY_CAUSE_DECRYPT_BAD_SIGNATURE,            /**< An S/MIME decryption operation aborted due to a bad signature. */
    SECURITY_CAUSE_DECRYPT_MISSING_SIGNATURE,        /**< An S/MIME decryption operation aborted due to a missing signature. */
    SECURITY_CAUSE_DECRYPT_SIGNATURE_REJECTED,       /**< An S/MIME decryption operation aborted because the signature was rejected. */
    SECURITY_CAUSE_TLS_SERVER_CERTIFICATE,           /**< A TLS server certificate is being presented to the application for possible rejection. 
                                                          The application must respond to this message.
                                                          If the application returns false, the certificate is rejected and the call will not
                                                          complete.  If the application returns true, the certificate is accepted. */
    SECURITY_CAUSE_TLS_BAD_PASSWORD,                /**< A TLS operation failed due to a bad password. */
    SECURITY_CAUSE_TLS_LIBRARY_FAILURE,             /**< A TLS operation failed. */
    SECURITY_CAUSE_REMOTE_HOST_UNREACHABLE,         /**< The remote host is not reachable. */
    SECURITY_CAUSE_TLS_CONNECTION_FAILURE,          /**< A TLS connection to the remote party failed. */
    SECURITY_CAUSE_TLS_HANDSHAKE_FAILURE,           /**< A failure occured during the TLS handshake. */
    SECURITY_CAUSE_SIGNATURE_NOTIFY,                /**< The SIGNATURE_NOTIFY event is fired when the user-agent
                                                         receives a SIP message with signed SMIME as its content.
                                                         The signer's certificate will be located in the info structure
                                                         associated with this event.  The application can choose to accept
                                                         the signature, by returning 'true' in response to this message
                                                         or can choose to reject the signature
                                                         by returning 'false' in response to this message. */
    SECURITY_CAUSE_TLS_CERTIFICATE_REJECTED         /** < The application has rejected the server's TLS certificate. */
} SIPX_SECURITY_CAUSE;


/**
 * Enumeration of possible media events
 */
typedef enum SIPX_MEDIA_EVENT
{
    MEDIA_UNKNOWN     = 0,      /**< Unknown or undefined media event, this is
                                     generally the sign of an internal error in 
                                     sipXtapi */
    MEDIA_LOCAL_START = 50000,  /**< Local media (audio or video) is being 
                                     sent to the remote party */
    MEDIA_LOCAL_STOP,           /**< Local media (audio or video) is no longer
                                     being sent to the remote party.  This may
                                     be caused by a local/remote hold 
                                     operation, call tear down, or error.  See
                                     the SIPX_MEDIA_CAUSE enumeration for more
                                     information. */
    MEDIA_REMOTE_START,         /**< Remote media (audio or video) is ready to
                                     be received.  If no audio/video is 
                                     received for longer then the idle period,
                                     a MEDIA_REMOTE_SILENT event will be fired.
                                     See sipxConfigSetConnectionIdleTimeout. */
    MEDIA_REMOTE_STOP,          /**< Remote media (audio or video) has been 
                                     stopped due to a hold or call tear down.*/
    MEDIA_REMOTE_SILENT,        /**< Remote media has not been received for 
                                     some configured period.  This generally 
                                     indicates a network problem and/or a
                                     problem with the remote party.  See 
                                     sipxConfigSetConnectionIdleTimeout for
                                     more information. */
    MEDIA_PLAYFILE_START,       /**< A file is being played to local and/or 
                                     remote parties.  This event will be
                                     followed by a MEDIA_PLAYFILE_STOP when
                                     the file is manually stopped or 
                                     finished playing. */
    MEDIA_PLAYFILE_FINISH,      /**< A file has completed playing. You need to
                                     call sipxCallAudioPlayFileStop() or
                                     sipxConferencePlayAudioFileStop() to prepare
                                     for the next file playback. */
    MEDIA_PLAYFILE_STOP,        /**< A file playback has been stopped.*/
    MEDIA_PLAYBUFFER_START,     /**< A buffer is being played to local and/or 
                                     remote parties.  This event will be
                                     followed by a MEDIA_PLAYBUFFER_STOP when
                                     the file is manually stopped or 
                                     finished playing. */
    MEDIA_PLAYBUFFER_FINISH,    /**< A buffer has completed playing. You need to
                                     call sipxCallPlayBufferStop() to prepare
                                     for the next buffer playback. */
    MEDIA_PLAYBUFFER_STOP,      /**< A buffer playback has been stopped.*/
    MEDIA_RECORDFILE_START,     /**< Recording to a file has started. This event
                                     will be followed by a MEDIA_RECORDFILE_STOP
                                     when the recording is manually stopped or 
                                     or finished after specified amount of time. */
    MEDIA_RECORDFILE_STOP,      /**< A recording has been manually stopped,
                                     automatically finished or aborted because
                                     of an error.*/
    MEDIA_RECORDBUFFER_START,   /**< Recording to a buffer has started. This event
                                     will be followed by a MEDIA_RECORDBUFFER_STOP
                                     when the recording is manually stopped or 
                                     or finished after specified amount of time. */
    MEDIA_RECORDBUFFER_STOP,    /**< A recording has been manually stopped,
                                     automatically finished or aborted because
                                     of an error.*/
    MEDIA_REMOTE_DTMF,          /**< A dtmf tone was started/stopped, see the
                                     cause codes for exact status */
    MEDIA_DEVICE_FAILURE,       /**< Fired if the media device is not present or
                                     already in use. */
    MEDIA_REMOTE_ACTIVE,        /**< Media has been received */
    MEDIA_MIC_ENERGY_LEVEL,     /**< Mic energy level - value in idleTime */
    MEDIA_H264_SPS,             /**< H.264 SPS parameter set recieved */
    MEDIA_H264_PPS              /**< H.264 PPS parameter set recieved */

} SIPX_MEDIA_EVENT ;


/**
 * Enumeration of possible KEEPALIVE events (EVENT_CATEGORY_KEEPALIVE)
 */
typedef enum SIPX_KEEPALIVE_EVENT
{
    KEEPALIVE_START,        /**< A keepalive attempt has been started.  The
                                 developer is responsible for stopping all
                                 keepalives.  In some cases, keepalives will
                                 be automatically stopped -- however do not 
                                 rely on that.*/
    KEEPALIVE_FEEDBACK,     /**< The keepalive process has obtained information
                                 regarding your NAT mapped address (or local 
                                 address).  Feedback events are sent with the
                                 mapped address from a STUN transaction or the 
                                 rport results from a SIP transaction. */
    KEEPALIVE_FAILURE,      /**< FAILURE events are only fired when the 
                                 physical send fails.  The application 
                                 developer should stop the keepalive or can monitor
                                 the keepalive until the condition changes (lack of 
                                 failure or feedback event). */
    KEEPALIVE_STOP          /**< A keepalive process has been stopped. */
} SIPX_KEEPALIVE_EVENT ;

/**
 * Enumeration of possible KEEPALIVE cause codes (EVENT_CATEGORY_KEEPALIVE)
 */
typedef enum SIPX_KEEPALIVE_CAUSE
{
    KEEPALIVE_CAUSE_NORMAL
} SIPX_KEEPALIVE_CAUSE ;


/**
 * Keepalive event information structure.   This information is passed as 
 * part of the sipXtapi callback mechanism.  Based on the 
 * SIPX_KEEPALIVE_CATEGORY, the application developer should cast the pInfo 
 * member of your callback to the appropriate structure.  
 *
 * @see SIPX_EVENT_CALLBACK_PROC
 * @see SIPX_EVENT_CATEGORY
 */
typedef struct SIPX_KEEPALIVE_INFO
{
    size_t                  nSize ;     /**< Size of the structure */
    SIPX_KEEPALIVE_EVENT    event ;     /**< Keepalive event identifier. */
    SIPX_KEEPALIVE_CAUSE    cause ;     /**< Keepalive cause  */
    SIPX_KEEPALIVE_TYPE     type ;      /**< Keepalive type */
    const char*             szRemoteAddress ;   /**< Target IP/host where you are sending the keepalives */
    int                     remotePort ;        /**< Target port where you are sending the keepalives */
    int                     keepAliveSecs ;     /**< How often keepalives are being sent */
    const char*             szFeedbackAddress;  /**< This UA's IP address as seen by the remote side (only 
                                                     valid in FEEDBACK events) */
    int                     feedbackPort ;      /**< This UA's port as seen by the remote side (only valid 
                                                     in FEEDBACK events) */
} SIPX_KEEPALIVE_INFO ;

/**
 * Enumeration of possible media event causes.
 */
typedef enum SIPX_MEDIA_CAUSE
{
    MEDIA_CAUSE_NORMAL,             /**< Normal cause; the call was likely torn down.*/
    MEDIA_CAUSE_HOLD,               /**< Media state changed due to a local or remote
                                         hold operation */
    MEDIA_CAUSE_UNHOLD,             /**< Media state changed due to a local or remote
                                         unhold operation */
    MEDIA_CAUSE_FAILED,             /**< Media state changed due to an error condition. */
    MEDIA_CAUSE_DEVICE_UNAVAILABLE, /**< Media state changed due to an error condition,
                                        (device was removed, already in use, etc). */
    MEDIA_CAUSE_INCOMPATIBLE,        /**< Incompatible destination -- We were unable
                                        to negotiate a codec */
    MEDIA_CAUSE_DTMF_START,          /**< A DTMF tone has started */
    MEDIA_CAUSE_DTMF_STOP            /**< A DTMF tone has stopped */

} SIPX_MEDIA_CAUSE ;

/**
 * Enumeration of possible media event types.  Today, MEDIA_TYPE_AUDIO and
 * MEDIA_TYPE_VIDEO are supported.
 */
typedef enum SIPX_MEDIA_TYPE
{
    MEDIA_TYPE_AUDIO,   /**< Audio media event type */
    MEDIA_TYPE_VIDEO,   /**< Video media event type */

} SIPX_MEDIA_TYPE ;


/**
 * Media event information structure.  This information is passed as part of 
 * the sipXtapi callback mechanism.  Based on the SIPX_EVENT_CATEGORY, the 
 * application developer should cast the pInfo member of your callback to the
 * appropriate structure.  
 *
 * @see SIPX_EVENT_CALLBACK_PROC
 * @see SIPX_EVENT_CATEGORY
 */
typedef struct SIPX_MEDIA_INFO
{
    size_t              nSize ;     /**< Size of the structure. */
    SIPX_MEDIA_EVENT    event ;     /**< Media event identifier.  See SIPX_MEDIA_EVENT 
                                         for more information. */
    SIPX_MEDIA_CAUSE    cause ;     /**< Media cause identifier.  See SIPX_MEDIA_CAUSE
                                         for more information. */
    SIPX_MEDIA_TYPE     mediaType ; /**< Media type: Either MEDIA_TYPE_AUDIO or 
                                         MEDIA_TYPE_VIDEO. */
    SIPX_CALL           hCall ;     /**< Associate call (or SIPX_CALL_NULL if 
                                         not associated with a call). */
    SIPX_CODEC_INFO     codec ;     /**< Negotiated codec; only supplied on 
                                         MEDIA_LOCAL_START and MEDIA_REMOTE_START
                                         events. */
    int                 idleTime;   /**< For MEDIA_REMOTE_SILENT events contains idle
                                         time (ms). For MEDIA_RECORDFILE_STOP and
                                         MEDIA_RECORDBUFFER_STOP events contains number
                                         of recorded samples. For other events this
                                         value should be ignored. 
                                         For MEDIA_MIC_ENERGY_LEVEL contains energy level*/
    SIPX_TONE_ID        toneId;	    /**< DTMF tone received from remote party;
                                         only supplied on MEDIA_REMOTE_DTMF event).
                                         Note: Only RFC 2833 DTMF detection is supported
                                         (not in-band DTMF or dialtone detection, 
                                         etc.)*/
} SIPX_MEDIA_INFO ;


/**
 * Callstate event information structure.   This information is passed as part of 
 * the sipXtapi callback mechanism.  Based on the SIPX_EVENT_CATEGORY, the 
 * application developer should cast the pInfo member of your callback to the
 * appropriate structure.  
 *
 * @see SIPX_EVENT_CALLBACK_PROC
 * @see SIPX_EVENT_CATEGORY
 */
typedef struct SIPX_CALLSTATE_INFO
{
    // TODO: Add a bitmask that identified which structure items are valid.  For 
    //       example, codec and hAssociatedCall are only valid for certain event
    //       sequences.

    size_t    nSize;                /**< The size of this structure. */
    SIPX_CALL hCall;                /**< Call handle associated with the callstate event. */
    SIPX_LINE hLine;                /**< Line handle associated with the callstate event. */
    SIPX_CALLSTATE_EVENT event;     /**< Callstate event enum code.
                                         Identifies the callstate event. */
    SIPX_CALLSTATE_CAUSE cause;     /**< Callstate cause enum code. 
                                         Identifies the cause of the callstate event. */
    SIPX_CALL hAssociatedCall ;     /**< Call associated with this event.  For example, when
                                         a new call is created as part of a consultative 
                                         transfer, this handle contains the handle of the 
                                         original call. */
} SIPX_CALLSTATE_INFO; 


/**
 * Linestate event information structure.   This information is passed as part of 
 * the sipXtapi callback mechanism.  Based on the SIPX_EVENT_CATEGORY, the 
 * application developer should cast the pInfo member of your callback to the
 * appropriate structure.  
 *
 * @see SIPX_EVENT_CALLBACK_PROC
 * @see SIPX_EVENT_CATEGORY
 */
typedef struct                      
{
    size_t    nSize ;               /**< The size of this structure. */
    SIPX_LINE hLine;                /**< Line handle associated with the linestate event. */ 
    SIPX_LINESTATE_EVENT event ;    /**< Callstate event enum code.
                                         Identifies the linestate event. */
    SIPX_LINESTATE_CAUSE cause ;    /**< Callstate cause enum code. 
                                         Identifies the cause of the linestate event. */
} SIPX_LINESTATE_INFO ;


/**
 *  Major classifications of response statuses for a SIP message.
 */
typedef enum SIPX_MESSAGE_STATUS
{
    SIPX_MESSAGE_OK,                  /**< The message was successfully processed (200) */ 
    SIPX_MESSAGE_FAILURE,             /**< The server received the message, but could or would
                                           not process it. */
    SIPX_MESSAGE_SERVER_FAILURE,      /**< The server encountered an error while trying to process
                                           the message. */
    SIPX_MESSAGE_GLOBAL_FAILURE,      /**< Fatal error encountered. */
} SIPX_MESSAGE_STATUS ;

/**
 * An INFOSTATUS event informs that application layer of the status
 * of an outbound INFO requests.   This information is passed as part of 
 * the sipXtapi callback mechanism.  Based on the SIPX_EVENT_CATEGORY, the 
 * application developer should cast the pInfo member of your callback to the
 * appropriate structure.  
 *
 * @see SIPX_EVENT_CALLBACK_PROC
 * @see SIPX_EVENT_CATEGORY
 */
typedef struct SIPX_INFOSTATUS_INFO
{
    size_t              nSize ;             /**< the size of this structure in bytes */
    SIPX_INFO           hInfo ;             /**< the handle used to make the outbound info request. */ 
    SIPX_MESSAGE_STATUS status ;            /**< Emumerated status for this
                                                 request acknowledgement. */
    int                 responseCode ;      /**< Numerical status code for this
                                                 request acknowledgement. */
    const char*         szResponseText ;    /**< The text of the request acknowledgement. */
    SIPX_INFOSTATUS_EVENT event;            /**< Event code for this INFO STATUS message */
} SIPX_INFOSTATUS_INFO ;


/**
 * An INFO event signals the application layer that an INFO message
 * was sent to this user agent.  If the INFO message was sent to a 
 * call context (session) hCall will desiginate the call session. 
 *
 * This information is passed as part of the sipXtapi callback mechanism.  
 * Based on the SIPX_EVENT_CATEGORY, the application developer should cast the
 * pInfo member of your callback to the appropriate structure.  
 *
 * @see SIPX_EVENT_CALLBACK_PROC
 * @see SIPX_EVENT_CATEGORY
 */
typedef struct SIPX_INFO_INFO
{
    size_t      nSize ;             /**< Size of structure */
    SIPX_CALL   hCall ;             /**< Call handle if available */
    SIPX_LINE   hLine ;             /**< Line handle if available */
    const char* szFromURL ;         /**< the URL of the host that originated
                                         the INFO message */
    const char* szUserAgent;        /**< the User Agent string of the source agent */
    const char* szContentType ;     /**< string indicating the info content type */
    const char* pContent ;          /**< pointer to the INFO message content */
    size_t      nContentLength ;    /**< length of the INFO message content */
  
} SIPX_INFO_INFO ;

/**
 * Enumeration of the possible subscription states visible to the client.
 */
typedef enum SIPX_SUBSCRIPTION_STATE
{
    SIPX_SUBSCRIPTION_PENDING,      /**< THe subscription is being set up, but not yet active. */
    SIPX_SUBSCRIPTION_ACTIVE ,      /**< The subscription is currently active. */
    SIPX_SUBSCRIPTION_FAILED ,      /**< The subscription is not active due to a failure.*/
    SIPX_SUBSCRIPTION_EXPIRED ,     /**< The subscription's lifetime has expired. */
    // TBD
} SIPX_SUBSCRIPTION_STATE;

/**
 * Enumeration of cause codes for state subscription state changes.
 */
typedef enum SIPX_SUBSCRIPTION_CAUSE
{
    SUBSCRIPTION_CAUSE_UNKNOWN = -1, /**< No cause specified. */
    SUBSCRIPTION_CAUSE_NORMAL     /**< Normal cause for state change. */
} SIPX_SUBSCRIPTION_CAUSE;

/**
 * An SUBSTATUS event informs that application layer of the status
 * of an outbound SUBSCRIPTION requests;
 *
 * This information is passed as part of the sipXtapi callback mechanism.  
 * Based on the SIPX_EVENT_CATEGORY, the application developer should cast the
 * pInfo member of your callback to the appropriate structure.  
 *
 * @see SIPX_EVENT_CALLBACK_PROC
 * @see SIPX_EVENT_CATEGORY
 */
typedef struct SIPX_SUBSTATUS_INFO
{
    size_t nSize ;                      /**< The size of this structure in bytes */
    SIPX_SUB hSub ;                     /**< A handle to the subscription to which
                                             this state change occurred. */
    SIPX_SUBSCRIPTION_STATE state ;     /**< Enum state value indicating the current
                                             state of the subscription. */
    SIPX_SUBSCRIPTION_CAUSE cause;      /**< Enum cause for the state change in this
                                             event. */
    const char* szSubServerUserAgent;   /**< The User Agent header field value from
                                             the SIP SUBSCRIBE response (may be NULL) */
    
} SIPX_SUBSTATUS_INFO ;


/**
 * A NOTIFY_INFO event signifies that a NOTIFY message was received for
 * an active subscription.
 *
 * This information is passed as part of the sipXtapi callback mechanism.  
 * Based on the SIPX_EVENT_CATEGORY, the application developer should cast the
 * pInfo member of your callback to the appropriate structure.  
 *
 * @see SIPX_EVENT_CALLBACK_PROC
 * @see SIPX_EVENT_CATEGORY
 */ 
typedef struct SIPX_NOTIFY_INFO
{
    size_t      nSize ;             /**< The size of this structure in bytes */
    SIPX_SUB    hSub ;              /**< A handle to the subscrption which
                                         caused this NOTIFY event to be received. */
    const char* szNotiferUserAgent; /**< The User-Agent header field value from
                                         the SIP NOTIFY response (may be NULL) */
    const char* szContentType ;     /**< String indicating the info content type */     
    const void* pContent ;          /**< Pointer to the NOTIFY message content */
    size_t      nContentLength ;    /**< Length of the NOTIFY message content in bytes */
} SIPX_NOTIFY_INFO ;


/**
 * SIPX_CONFIG_INFO events signifies that a change in configuration was 
 * observed.
 *
 * NOTE: This structure is subject to change. 
 *
 * This information is passed as part of the sipXtapi callback mechanism.  
 * Based on the SIPX_EVENT_CATEGORY, the application developer should cast the
 * pInfo member of your callback to the appropriate structure.  
 *
 * @see SIPX_EVENT_CALLBACK_PROC
 * @see SIPX_EVENT_CATEGORY
 */ 
typedef struct SIPX_CONFIG_INFO
{
    size_t            nSize ;   /**< The size of this structure in bytes */
    SIPX_CONFIG_EVENT event ;   /**< Event code -- see SIPX_CONFIG_EVENT for 
                                     details. */
    void*             pData;    /**< Pointer to event data -- SEE SIPX_CONFIG_EVENT
                                     for details. */
} SIPX_CONFIG_INFO ;
					      

/**
 * An SIPX_SECURITY_INFO event informs that application layer of the status
 * of a security operation.
 *
 * This information is passed as part of the sipXtapi callback mechanism.  
 * Based on the SIPX_EVENT_CATEGORY, the application developer should cast the
 * pInfo member of your callback to the appropriate structure.  
 *
 * @see SIPX_EVENT_CALLBACK_PROC
 * @see SIPX_EVENT_CATEGORY
 */
typedef struct SIPX_SECURITY_INFO
{
    size_t              nSize ;             /**< the size of this structure in bytes */
    char*               szSRTPkey;          /**< the negotiated SRTP key, if any. */
    void*               pCertificate;       /**< pointer to the certificate blob that was
                                                 used to encrypt and/or sign. */
    int                 nCertificateSize;   /**< size of the certificate blob */
    SIPX_SECURITY_EVENT event;              /**< Event code for this SECURITY_INFO message */
    SIPX_SECURITY_CAUSE cause;              /**< Cause code for this SECURITY_INFO message*/
    char*               szSubjAltName;      /**< Populated for SECURITY_CAUSE_SIGNATURE_NOTIFY.*/
    char*               callId;             /**< Points to a call-id string associated with the event.
                                                 Can be NULL. */
    SIPX_CALL           hCall;              /**< A call handle associated with the event.  Can be 0, 
                                                 to signify that the event is not associated with a call. */
    char*               remoteAddress;      /**< A remote address associated with the event.  Can be NULL. */
} SIPX_SECURITY_INFO ;


/* ============================ FUNCTIONS ================================= */

/**
 * Duplicate the event information for a sipXtapi event.  This method is only
 * needed if you wish to post the event information to another thread context.
 * Once the event has been handled, you must call sipxFreeDuplicatedEvent on
 * the copy to avoid memory leaks.
 *
 * @param category Category type supplied by the sipXtapi event callback.
 * @param pEventSource Source of event data supplied by the sipXtapi event 
 *        callback.
 * @param pEventCopy New copy of the event data.  This data must be freed
 *        by calling sipxFreeDuplicatedEvent.
 */
SIPXTAPI_API SIPX_RESULT sipxDuplicateEvent(SIPX_EVENT_CATEGORY category, 
                                            const void*         pEventSource, 
                                            void**              pEventCopy) ;


/**
 * Frees up memory allocated as part of sipxDuplicateEvent. Do not call this
 * API on pointers received as part of the sipXtapi call back.
 *
 * @param category Category type supplied by the sipXtapi event callback.
 * @param pEventCopy Copy of event data supplied by sipxDuplicateEvent.
 */
SIPXTAPI_API SIPX_RESULT sipxFreeDuplicatedEvent(SIPX_EVENT_CATEGORY category, 
                                                 void*               pEventCopy) ;

/**
 * Add a callback/observer for the purpose of receiving sipXtapi events
 *
 * @param hInst Instance pointer obtained by sipxInitialize.
 * @param pCallbackProc Function to receive sipx events
 * @param pUserData user data passed along with event data
 */
SIPXTAPI_API SIPX_RESULT sipxEventListenerAdd(const SIPX_INST hInst,
                                             SIPX_EVENT_CALLBACK_PROC pCallbackProc,
                                             void *pUserData);
                                             
/**
 * Remove a sipXtapi event callback/observer.  Supply the same
 * pCallbackProc and pUserData values as sipxEventListenerAdd.
 *
 * @param hInst Instance pointer obtained by sipxInitialize.
 * @param pCallbackProc Function used to receive sipx events
 * @param pUserData user data specified as part of sipxListenerAdd
 */
SIPXTAPI_API SIPX_RESULT sipxEventListenerRemove(const SIPX_INST hInst, 
                                                 SIPX_EVENT_CALLBACK_PROC pCallbackProc, 
                                                 void* pUserData) ;

/* ============================ FUNCTIONS ================================= */

/**
 * Create a printable string version of the designated call state event ids.
 * This is generally used for debugging.
 *
 * @param event sipxtapi event code
 * @param cause sipxtapi cause event code
 * @param szBuffer buffer to store event string
 * @param nBuffer length of string buffer szBuffer
 */
SIPXTAPI_API char* sipxCallEventToString(SIPX_CALLSTATE_EVENT event,
                                         SIPX_CALLSTATE_CAUSE cause,
                                         char*  szBuffer,
                                         size_t nBuffer) ;


/**
 * Create a printable string version of the designated event.
 * This is generally used for debugging.
 *
 * @param category Event category code
 * @param pEvent Pointer to the Event.
 * @param szBuffer buffer to store event string
 * @param nBuffer length of string buffer szBuffer
 */
SIPXTAPI_API char* sipxEventToString(const SIPX_EVENT_CATEGORY category,
                                     const void* pEvent,
                                     char*  szBuffer,
                                     size_t nBuffer);

/**
 * Create a printable string version of the designated line event ids.
 * This is generally used for debugging.
 *
 * @deprecated Use sipxEventToString instead.
 * @param event major event type id
 * @param cause event type id
 * @param szBuffer buffer to store event string
 * @param nBuffer length of string buffer szBuffer
 */
SIPXTAPI_API char* sipxLineEventToString(SIPX_LINESTATE_EVENT event,
                                         SIPX_LINESTATE_CAUSE cause,
                                         char*  szBuffer,
                                         size_t nBuffer);
 

/**
 * Create a printable string version of the designated config event.
 * This is generally used for debugging.
 *
 * @param event Configuration event id
 * @param szBuffer Buffer to store event string
 * @param nBuffer Length of string buffer szBuffer
 */
SIPXTAPI_API char* sipxConfigEventToString(SIPX_CONFIG_EVENT event, 
                                           char* szBuffer, 
                                           size_t nBuffer) ;

/** 
 * Create a printable string version of the designated subscription status state. 
 * This is generally used for debugging. 
 * 
 * @param state Subscription state id 
 * @param szBuffer Buffer to store event string 
 * @param nBuffer Length of string buffer szBuffer 
 */ 
SIPXTAPI_API char* sipxSubStatusStateToString(SIPX_SUBSCRIPTION_STATE state, 
                                            char* szBuffer, 
                                            size_t nBuffer) ; 
                                            
/** 
 * Create a printable string version of the designated subscription status cause. 
 * This is generally used for debugging. 
 * 
 * @param cause Subscription cause id 
 * @param szBuffer Buffer to store event string 
 * @param nBuffer Length of string buffer szBuffer 
 */ 
SIPXTAPI_API char* sipxSubStatusCauseToString(SIPX_SUBSCRIPTION_CAUSE cause, 
                                            char* szBuffer, 
                                            size_t nBuffer) ; 

/**
 * Create a printable string version of the designated security event.
 * This is generally used for debugging.
 *
 * @param event Security event id
 * @param szBuffer Buffer to store event string
 * @param nBuffer Length of string buffer szBuffer
 */
SIPXTAPI_API char* sipxSecurityEventToString(SIPX_SECURITY_EVENT event, 
                                           char* szBuffer, 
                                           size_t nBuffer);

/**
 * Create a printable string version of the designated security cause.
 * This is generally used for debugging.
 *
 * @param cause Security cause id
 * @param szBuffer Buffer to store cause string
 * @param nBuffer Length of string buffer szBuffer
 */
SIPXTAPI_API char* sipxSecurityCauseToString(SIPX_SECURITY_CAUSE cause, 
                                           char* szBuffer, 
                                           size_t nBuffer);

/**
 * Create a printable string version of the designated media event.
 * This is generally used for debugging.
 *
 * @param event Media event id
 * @param szBuffer Buffer to store event string
 * @param nBuffer Length of string buffer szBuffer
 */
SIPXTAPI_API char* sipxMediaEventToString(SIPX_MEDIA_EVENT event,
                                          char* szBuffer,
                                          size_t nBuffer);

/**
 * Create a printable string version of the designated media cause.
 * This is generally used for debugging.
 *
 * @param cause Media cause id
 * @param szBuffer Buffer to store cause string
 * @param nBuffer Length of string buffer szBuffer
 */
SIPXTAPI_API char* sipxMediaCauseToString(SIPX_MEDIA_CAUSE cause,
                                          char* szBuffer,
                                          size_t nBuffer);

/**
* Create a printable string version of the designated keepalive event.
* This is generally used for debugging.
*
* @param event Keepalive event id
* @param szBuffer Buffer to store event string
* @param nBuffer Length of string buffer szBuffer
*/
SIPXTAPI_API char* sipxKeepaliveEventToString(SIPX_KEEPALIVE_EVENT event,
                                              char* szBuffer,
                                              size_t nBuffer);

/**
* Create a printable string version of the designated keepalive cause.
* This is generally used for debugging.
*
* @param cause Keepalive cause id
* @param szBuffer Buffer to store cause string
* @param nBuffer Length of string buffer szBuffer
*/
SIPXTAPI_API char* sipxKeepaliveCauseToString(SIPX_KEEPALIVE_CAUSE cause,
                                              char* szBuffer,
                                              size_t nBuffer);

#endif /* ifndef _sipXtapiEvents_h_ */