~singpolyma/asterisk

ref: 51af79b42e4ae7d1831603633d73bf0df179720e asterisk/main/ccss.c -rw-r--r-- 153.3 KiB
51af79b4Christopher Vollick Content Created By Initiator 2: Electric Boogaloo 9 months ago
                                                                                
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
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
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2010, Digium, Inc.
 *
 * Mark Michelson <mmichelson@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 Call Completion Supplementary Services implementation
 * \author Mark Michelson <mmichelson@digium.com>
 */

/*! \li \ref ccss.c uses the configuration file \ref ccss.conf
 * \addtogroup configuration_file Configuration Files
 */

/*!
 * \page ccss.conf ccss.conf
 * \verbinclude ccss.conf.sample
 */

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

#include "asterisk.h"

#include "asterisk/astobj2.h"
#include "asterisk/strings.h"
#include "asterisk/ccss.h"
#include "asterisk/channel.h"
#include "asterisk/pbx.h"
#include "asterisk/utils.h"
#include "asterisk/taskprocessor.h"
#include "asterisk/devicestate.h"
#include "asterisk/module.h"
#include "asterisk/app.h"
#include "asterisk/cli.h"
#include "asterisk/manager.h"
#include "asterisk/causes.h"
#include "asterisk/stasis_system.h"
#include "asterisk/format_cache.h"

/*** DOCUMENTATION
	<application name="CallCompletionRequest" language="en_US">
		<synopsis>
			Request call completion service for previous call
		</synopsis>
		<syntax />
		<description>
			<para>Request call completion service for a previously failed
			call attempt.</para>
			<para>This application sets the following channel variables:</para>
			<variablelist>
				<variable name="CC_REQUEST_RESULT">
					<para>This is the returned status of the request.</para>
					<value name="SUCCESS" />
					<value name="FAIL" />
				</variable>
				<variable name="CC_REQUEST_REASON">
					<para>This is the reason the request failed.</para>
					<value name="NO_CORE_INSTANCE" />
					<value name="NOT_GENERIC" />
					<value name="TOO_MANY_REQUESTS" />
					<value name="UNSPECIFIED" />
				</variable>
			</variablelist>
		</description>
	</application>
	<application name="CallCompletionCancel" language="en_US">
		<synopsis>
			Cancel call completion service
		</synopsis>
		<syntax />
		<description>
			<para>Cancel a Call Completion Request.</para>
			<para>This application sets the following channel variables:</para>
			<variablelist>
				<variable name="CC_CANCEL_RESULT">
					<para>This is the returned status of the cancel.</para>
					<value name="SUCCESS" />
					<value name="FAIL" />
				</variable>
				<variable name="CC_CANCEL_REASON">
					<para>This is the reason the cancel failed.</para>
					<value name="NO_CORE_INSTANCE" />
					<value name="NOT_GENERIC" />
					<value name="UNSPECIFIED" />
				</variable>
			</variablelist>
		</description>
	</application>
 ***/

/* These are some file-scoped variables. It would be
 * nice to define them closer to their first usage, but since
 * they are used in many places throughout the file, defining
 * them here at the top is easiest.
 */

/*!
 * The ast_sched_context used for all generic CC timeouts
 */
static struct ast_sched_context *cc_sched_context;
/*!
 * Counter used to create core IDs for CC calls. Each new
 * core ID is created by atomically adding 1 to the core_id_counter
 */
static int core_id_counter;
/*!
 * Taskprocessor from which all CC agent and monitor callbacks
 * are called.
 */
static struct ast_taskprocessor *cc_core_taskprocessor;
/*!
 * Name printed on all CC log messages.
 */
static const char *CC_LOGGER_LEVEL_NAME = "CC";
/*!
 * Logger level registered by the CC core.
 */
static int cc_logger_level;
/*!
 * Parsed configuration value for cc_max_requests
 */
static unsigned int global_cc_max_requests;
/*!
 * The current number of CC requests in the system
 */
static int cc_request_count;

static inline void *cc_ref(void *obj, const char *debug)
{
	ao2_t_ref(obj, +1, debug);
	return obj;
}

static inline void *cc_unref(void *obj, const char *debug)
{
	ao2_t_ref(obj, -1, debug);
	return NULL;
}

/*!
 * \since 1.8
 * \internal
 * \brief A structure for holding the configuration parameters
 * relating to CCSS
 */
struct ast_cc_config_params {
	enum ast_cc_agent_policies cc_agent_policy;
	enum ast_cc_monitor_policies cc_monitor_policy;
	unsigned int cc_offer_timer;
	unsigned int ccnr_available_timer;
	unsigned int ccbs_available_timer;
	unsigned int cc_recall_timer;
	unsigned int cc_max_agents;
	unsigned int cc_max_monitors;
	char cc_callback_macro[AST_MAX_EXTENSION];
	char cc_callback_sub[AST_MAX_EXTENSION];
	char cc_agent_dialstring[AST_MAX_EXTENSION];
};

/*!
 * \since 1.8
 * \brief The states used in the CCSS core state machine
 *
 * For more information, see doc/CCSS_architecture.pdf
 */
enum cc_state {
	/*! Entered when it is determined that CCSS may be used for the call */
	CC_AVAILABLE,
	/*! Entered when a CCSS agent has offered CCSS to a caller */
	CC_CALLER_OFFERED,
	/*! Entered when a CCSS agent confirms that a caller has
	 * requested CCSS */
	CC_CALLER_REQUESTED,
	/*! Entered when a CCSS monitor confirms acknowledgment of an
	 * outbound CCSS request */
	CC_ACTIVE,
	/*! Entered when a CCSS monitor alerts the core that the called party
	 * has become available */
	CC_CALLEE_READY,
	/*! Entered when a CCSS agent alerts the core that the calling party
	 * may not be recalled because he is unavailable
	 */
	CC_CALLER_BUSY,
	/*! Entered when a CCSS agent alerts the core that the calling party
	 * is attempting to recall the called party
	 */
	CC_RECALLING,
	/*! Entered when an application alerts the core that the calling party's
	 * recall attempt has had a call progress response indicated
	 */
	CC_COMPLETE,
	/*! Entered any time that something goes wrong during the process, thus
	 * resulting in the failure of the attempted CCSS transaction. Note also
	 * that cancellations of CC are treated as failures.
	 */
	CC_FAILED,
};

/*!
 * \brief The payload for an AST_CONTROL_CC frame
 *
 * \details
 * This contains all the necessary data regarding
 * a called device so that the CC core will be able
 * to allocate the proper monitoring resources.
 */
struct cc_control_payload {
	/*!
	 * \brief The type of monitor to allocate.
	 *
	 * \details
	 * The type of monitor to allocate. This is a string which corresponds
	 * to a set of monitor callbacks registered. Examples include "generic"
	 * and "SIP"
	 *
	 * \note This really should be an array of characters in case this payload
	 * is sent accross an IAX2 link.  However, this would not make too much sense
	 * given this type may not be recognized by the other end.
	 * Protection may be necessary to prevent it from being transmitted.
	 *
	 * In addition the following other problems are also possible:
	 * 1) Endian issues with the integers/enums stored in the config_params.
	 * 2) Alignment padding issues for the element types.
	 */
	const char *monitor_type;
	/*!
	 * \brief Private data allocated by the callee
	 *
	 * \details
	 * All channel drivers that monitor endpoints will need to allocate
	 * data that is not usable by the CC core. In most cases, some or all
	 * of this data is allocated at the time that the channel driver offers
	 * CC to the caller. There are many opportunities for failures to occur
	 * between when a channel driver offers CC and when a monitor is actually
	 * allocated to watch the endpoint. For this reason, the channel driver
	 * must give the core a pointer to the private data that was allocated so
	 * that the core can call back into the channel driver to destroy it if
	 * a failure occurs. If no private data has been allocated at the time that
	 * CC is offered, then it is perfectly acceptable to pass NULL for this
	 * field.
	 */
	void *private_data;
	/*!
	 * \brief Service offered by the endpoint
	 *
	 * \details
	 * This indicates the type of call completion service offered by the
	 * endpoint. This data is not crucial to the machinations of the CC core,
	 * but it is helpful for debugging purposes.
	 */
	enum ast_cc_service_type service;
	/*!
	 * \brief Configuration parameters used by this endpoint
	 *
	 * \details
	 * Each time an endpoint offers call completion, it must provide its call
	 * completion configuration parameters. This is because settings may be different
	 * depending on the circumstances.
	 */
	struct ast_cc_config_params config_params;
	/*!
	 * \brief ID of parent extension
	 *
	 * \details
	 * This is the only datum that the CC core derives on its own and is not
	 * provided by the offerer of CC. This provides the core with information on
	 * which extension monitor is the most immediate parent of this device.
	 */
	int parent_interface_id;
	/*!
	 * \brief Name of device to be monitored
	 *
	 * \details
	 * The device name by which this monitored endpoint will be referred in the
	 * CC core. It is highly recommended that this device name is derived by using
	 * the function ast_channel_get_device_name.
	 */
	char device_name[AST_CHANNEL_NAME];
	/*!
	 * \brief Recall dialstring
	 *
	 * \details
	 * Certain channel drivers (DAHDI in particular) will require that a special
	 * dialstring be used to indicate that the outgoing call is to interpreted as
	 * a CC recall. If the channel driver has such a requirement, then this is
	 * where that special recall dialstring is placed. If no special dialstring
	 * is to be used, then the channel driver must provide the original dialstring
	 * used to call this endpoint.
	 */
	char dialstring[AST_CHANNEL_NAME];
};

/*!
 * \brief The "tree" of interfaces that is dialed.
 *
 * \details
 * Though this is a linked list, it is logically treated
 * as a tree of monitors. Each monitor has an id and a parent_id
 * associated with it. The id is a unique ID for that monitor, and
 * the parent_id is the unique ID of the monitor's parent in the
 * tree. The tree is structured such that all of a parent's children
 * will appear after the parent in the tree. However, it cannot be
 * guaranteed exactly where after the parent the children are.
 *
 * The tree is reference counted since several threads may need
 * to use it, and it may last beyond the lifetime of a single
 * thread.
 */
AST_LIST_HEAD(cc_monitor_tree, ast_cc_monitor);

static const int CC_CORE_INSTANCES_BUCKETS = 17;
static struct ao2_container *cc_core_instances;

struct cc_core_instance {
	/*!
	 * Unique identifier for this instance of the CC core.
	 */
	int core_id;
	/*!
	 * The current state for this instance of the CC core.
	 */
	enum cc_state current_state;
	/*!
	 * The CC agent in use for this call
	 */
	struct ast_cc_agent *agent;
	/*!
	 * Reference to the monitor tree formed during the initial call
	 */
	struct cc_monitor_tree *monitors;
};

/*!
 * \internal
 * \brief Request that the core change states
 * \param state The state to which we wish to change
 * \param core_id The unique identifier for this instance of the CCSS core state machine
 * \param debug Optional message explaining the reason for the state change
 * \param ap varargs list
 * \retval 0 State change successfully queued
 * \retval -1 Unable to queue state change request
 */
static int __attribute__((format(printf, 3, 0))) cc_request_state_change(enum cc_state state, const int core_id, const char *debug, va_list ap);

/*!
 * \internal
 * \brief create a new instance of the CC core and an agent for the calling channel
 *
 * This function will check to make sure that the incoming channel
 * is allowed to request CC by making sure that the incoming channel
 * has not exceeded its maximum number of allowed agents.
 *
 * Should that check pass, the core instance is created, and then the
 * agent for the channel.
 *
 * \param caller_chan The incoming channel for this particular call
 * \param called_tree A reference to the tree of called devices. The agent
 * will gain a reference to this tree as well
 * \param core_id The core_id that this core_instance will assume
 * \retval NULL Failed to create the core instance either due to memory allocation
 * errors or due to the agent count for the caller being too high
 * \retval non-NULL A reference to the newly created cc_core_instance
 */
static struct cc_core_instance *cc_core_init_instance(struct ast_channel *caller_chan,
		struct cc_monitor_tree *called_tree, const int core_id, struct cc_control_payload *cc_data);

static const struct {
	enum ast_cc_service_type service;
	const char *service_string;
} cc_service_to_string_map[] = {
	{AST_CC_NONE, "NONE"},
	{AST_CC_CCBS, "CCBS"},
	{AST_CC_CCNR, "CCNR"},
	{AST_CC_CCNL, "CCNL"},
};

static const struct {
	enum cc_state state;
	const char *state_string;
} cc_state_to_string_map[] = {
	{CC_AVAILABLE,          "CC is available"},
	{CC_CALLER_OFFERED,     "CC offered to caller"},
	{CC_CALLER_REQUESTED,   "CC requested by caller"},
	{CC_ACTIVE,             "CC accepted by callee"},
	{CC_CALLEE_READY,       "Callee has become available"},
	{CC_CALLER_BUSY,        "Callee was ready, but caller is now unavailable"},
	{CC_RECALLING,          "Caller is attempting to recall"},
	{CC_COMPLETE,           "Recall complete"},
	{CC_FAILED,             "CC has failed"},
};

static const char *cc_state_to_string(enum cc_state state)
{
	return cc_state_to_string_map[state].state_string;
}

static const char *cc_service_to_string(enum ast_cc_service_type service)
{
	return cc_service_to_string_map[service].service_string;
}

static int cc_core_instance_hash_fn(const void *obj, const int flags)
{
	const struct cc_core_instance *core_instance = obj;
	return core_instance->core_id;
}

static int cc_core_instance_cmp_fn(void *obj, void *arg, int flags)
{
	struct cc_core_instance *core_instance1 = obj;
	struct cc_core_instance *core_instance2 = arg;

	return core_instance1->core_id == core_instance2->core_id ? CMP_MATCH | CMP_STOP : 0;
}

static struct cc_core_instance *find_cc_core_instance(const int core_id)
{
	struct cc_core_instance finder = {.core_id = core_id,};

	return ao2_t_find(cc_core_instances, &finder, OBJ_POINTER, "Finding a core_instance");
}

struct cc_callback_helper {
	ao2_callback_fn *function;
	void *args;
	const char *type;
};

static int cc_agent_callback_helper(void *obj, void *args, int flags)
{
	struct cc_core_instance *core_instance = obj;
	struct cc_callback_helper *helper = args;

	if (strcmp(core_instance->agent->callbacks->type, helper->type)) {
		return 0;
	}

	return helper->function(core_instance->agent, helper->args, flags);
}

struct ast_cc_agent *ast_cc_agent_callback(int flags, ao2_callback_fn *function, void *args, const char * const type)
{
	struct cc_callback_helper helper = {.function = function, .args = args, .type = type};
	struct cc_core_instance *core_instance;
	if ((core_instance = ao2_t_callback(cc_core_instances, flags, cc_agent_callback_helper, &helper,
					"Calling provided agent callback function"))) {
		struct ast_cc_agent *agent = cc_ref(core_instance->agent, "An outside entity needs the agent");
		cc_unref(core_instance, "agent callback done with the core_instance");
		return agent;
	}
	return NULL;
}

enum match_flags {
	/* Only match agents that have not yet
	 * made a CC request
	 */
	MATCH_NO_REQUEST = (1 << 0),
	/* Only match agents that have made
	 * a CC request
	 */
	MATCH_REQUEST = (1 << 1),
};

/* ao2_callbacks for cc_core_instances */

/*!
 * \internal
 * \brief find a core instance based on its agent
 *
 * The match flags tell whether we wish to find core instances
 * that have a monitor or core instances that do not. Core instances
 * with no monitor are core instances for which a caller has not yet
 * requested CC. Core instances with a monitor are ones for which the
 * caller has requested CC.
 */
static int match_agent(void *obj, void *arg, void *data, int flags)
{
	struct cc_core_instance *core_instance = obj;
	const char *name = arg;
	unsigned long match_flags = *(unsigned long *)data;
	int possible_match = 0;

	if ((match_flags & MATCH_NO_REQUEST) && core_instance->current_state < CC_CALLER_REQUESTED) {
		possible_match = 1;
	}

	if ((match_flags & MATCH_REQUEST) && core_instance->current_state >= CC_CALLER_REQUESTED) {
		possible_match = 1;
	}

	if (!possible_match) {
		return 0;
	}

	if (!strcmp(core_instance->agent->device_name, name)) {
		return CMP_MATCH | CMP_STOP;
	}
	return 0;
}

struct count_agents_cb_data {
	int count;
	int core_id_exception;
};

/*!
 * \internal
 * \brief Count the number of agents a specific interface is using
 *
 * We're only concerned with the number of agents that have requested
 * CC, so we restrict our search to core instances which have a non-NULL
 * monitor pointer
 */
static int count_agents_cb(void *obj, void *arg, void *data, int flags)
{
	struct cc_core_instance *core_instance = obj;
	const char *name = arg;
	struct count_agents_cb_data *cb_data = data;

	if (cb_data->core_id_exception == core_instance->core_id) {
		ast_log_dynamic_level(cc_logger_level, "Found agent with core_id %d but not counting it toward total\n", core_instance->core_id);
		return 0;
	}

	if (core_instance->current_state >= CC_CALLER_REQUESTED && !strcmp(core_instance->agent->device_name, name)) {
		cb_data->count++;
	}
	return 0;
}

/* default values mapping from cc_state to ast_dev_state */

#define CC_AVAILABLE_DEVSTATE_DEFAULT        AST_DEVICE_NOT_INUSE
#define CC_CALLER_OFFERED_DEVSTATE_DEFAULT   AST_DEVICE_NOT_INUSE
#define CC_CALLER_REQUESTED_DEVSTATE_DEFAULT AST_DEVICE_NOT_INUSE
#define CC_ACTIVE_DEVSTATE_DEFAULT           AST_DEVICE_INUSE
#define CC_CALLEE_READY_DEVSTATE_DEFAULT     AST_DEVICE_RINGING
#define CC_CALLER_BUSY_DEVSTATE_DEFAULT      AST_DEVICE_ONHOLD
#define CC_RECALLING_DEVSTATE_DEFAULT        AST_DEVICE_RINGING
#define CC_COMPLETE_DEVSTATE_DEFAULT         AST_DEVICE_NOT_INUSE
#define CC_FAILED_DEVSTATE_DEFAULT           AST_DEVICE_NOT_INUSE

/*!
 * \internal
 * \brief initialization of defaults for CC_STATE to DEVICE_STATE map
 */
static enum ast_device_state cc_state_to_devstate_map[] = {
	[CC_AVAILABLE] =        CC_AVAILABLE_DEVSTATE_DEFAULT,
	[CC_CALLER_OFFERED] =   CC_CALLER_OFFERED_DEVSTATE_DEFAULT,
	[CC_CALLER_REQUESTED] = CC_CALLER_REQUESTED_DEVSTATE_DEFAULT,
	[CC_ACTIVE] =           CC_ACTIVE_DEVSTATE_DEFAULT,
	[CC_CALLEE_READY] =     CC_CALLEE_READY_DEVSTATE_DEFAULT,
	[CC_CALLER_BUSY] =      CC_CALLER_BUSY_DEVSTATE_DEFAULT,
	[CC_RECALLING] =        CC_RECALLING_DEVSTATE_DEFAULT,
	[CC_COMPLETE] =         CC_COMPLETE_DEVSTATE_DEFAULT,
	[CC_FAILED] =           CC_FAILED_DEVSTATE_DEFAULT,
};

/*!
 * \internal
 * \brief lookup the ast_device_state mapped to cc_state
 *
 * \param state
 *
 * \return the correponding DEVICE STATE from the cc_state_to_devstate_map
 * when passed an internal state.
 */
static enum ast_device_state cc_state_to_devstate(enum cc_state state)
{
	return cc_state_to_devstate_map[state];
}

/*!
 * \internal
 * \brief Callback for devicestate providers
 *
 * \details
 * Initialize with ast_devstate_prov_add() and returns the corresponding
 * DEVICE STATE based on the current CC_STATE state machine if the requested
 * device is found and is a generic device. Returns the equivalent of
 * CC_FAILED, which defaults to NOT_INUSE, if no device is found.  NOT_INUSE would
 * indicate that there is no presence of any pending call back.
 */
static enum ast_device_state ccss_device_state(const char *device_name)
{
	struct cc_core_instance *core_instance;
	unsigned long match_flags;
	enum ast_device_state cc_current_state;

	match_flags = MATCH_NO_REQUEST;
	core_instance = ao2_t_callback_data(cc_core_instances, 0, match_agent,
		(char *) device_name, &match_flags,
		"Find Core Instance for ccss_device_state reqeust.");
	if (!core_instance) {
		ast_log_dynamic_level(cc_logger_level,
			"Couldn't find a core instance for caller %s\n", device_name);
		return cc_state_to_devstate(CC_FAILED);
	}

	ast_log_dynamic_level(cc_logger_level,
		"Core %d: Found core_instance for caller %s in state %s\n",
		core_instance->core_id, device_name, cc_state_to_string(core_instance->current_state));

	if (strcmp(core_instance->agent->callbacks->type, "generic")) {
		ast_log_dynamic_level(cc_logger_level,
			"Core %d: Device State is only for generic agent types.\n",
			core_instance->core_id);
		cc_unref(core_instance, "Unref core_instance since ccss_device_state was called with native agent");
		return cc_state_to_devstate(CC_FAILED);
	}
	cc_current_state = cc_state_to_devstate(core_instance->current_state);
	cc_unref(core_instance, "Unref core_instance done with ccss_device_state");
	return cc_current_state;
}

/*!
 * \internal
 * \brief Notify Device State Changes from CC STATE MACHINE
 *
 * \details
 * Any time a state is changed, we call this function to notify the DEVICE STATE
 * subsystem of the change so that subscribed phones to any corresponding hints that
 * are using that state are updated.
 */
static void ccss_notify_device_state_change(const char *device, enum cc_state state)
{
	enum ast_device_state devstate;

	devstate = cc_state_to_devstate(state);

	ast_log_dynamic_level(cc_logger_level,
		"Notification of CCSS state change to '%s', device state '%s' for device '%s'\n",
		cc_state_to_string(state), ast_devstate2str(devstate), device);

	ast_devstate_changed(devstate, AST_DEVSTATE_CACHABLE, "ccss:%s", device);
}

#define CC_OFFER_TIMER_DEFAULT			20		/* Seconds */
#define CCNR_AVAILABLE_TIMER_DEFAULT	7200	/* Seconds */
#define CCBS_AVAILABLE_TIMER_DEFAULT	4800	/* Seconds */
#define CC_RECALL_TIMER_DEFAULT			20		/* Seconds */
#define CC_MAX_AGENTS_DEFAULT			5
#define CC_MAX_MONITORS_DEFAULT			5
#define GLOBAL_CC_MAX_REQUESTS_DEFAULT	20

static const struct ast_cc_config_params cc_default_params = {
	.cc_agent_policy = AST_CC_AGENT_NEVER,
	.cc_monitor_policy = AST_CC_MONITOR_NEVER,
	.cc_offer_timer = CC_OFFER_TIMER_DEFAULT,
	.ccnr_available_timer = CCNR_AVAILABLE_TIMER_DEFAULT,
	.ccbs_available_timer = CCBS_AVAILABLE_TIMER_DEFAULT,
	.cc_recall_timer = CC_RECALL_TIMER_DEFAULT,
	.cc_max_agents = CC_MAX_AGENTS_DEFAULT,
	.cc_max_monitors = CC_MAX_MONITORS_DEFAULT,
	.cc_callback_macro = "",
	.cc_callback_sub = "",
	.cc_agent_dialstring = "",
};

void ast_cc_default_config_params(struct ast_cc_config_params *params)
{
	*params = cc_default_params;
}

struct ast_cc_config_params *__ast_cc_config_params_init(const char *file, int line, const char *function)
{
	struct ast_cc_config_params *params = __ast_malloc(sizeof(*params), file, line, function);

	if (!params) {
		return NULL;
	}

	ast_cc_default_config_params(params);
	return params;
}

void ast_cc_config_params_destroy(struct ast_cc_config_params *params)
{
	ast_free(params);
}

static enum ast_cc_agent_policies str_to_agent_policy(const char * const value)
{
	if (!strcasecmp(value, "never")) {
		return AST_CC_AGENT_NEVER;
	} else if (!strcasecmp(value, "native")) {
		return AST_CC_AGENT_NATIVE;
	} else if (!strcasecmp(value, "generic")) {
		return AST_CC_AGENT_GENERIC;
	} else {
		ast_log(LOG_WARNING, "%s is an invalid value for cc_agent_policy. Switching to 'never'\n", value);
		return AST_CC_AGENT_NEVER;
	}
}

static enum ast_cc_monitor_policies str_to_monitor_policy(const char * const value)
{
	if (!strcasecmp(value, "never")) {
		return AST_CC_MONITOR_NEVER;
	} else if (!strcasecmp(value, "native")) {
		return AST_CC_MONITOR_NATIVE;
	} else if (!strcasecmp(value, "generic")) {
		return AST_CC_MONITOR_GENERIC;
	} else if (!strcasecmp(value, "always")) {
		return AST_CC_MONITOR_ALWAYS;
	} else {
		ast_log(LOG_WARNING, "%s is an invalid value for cc_monitor_policy. Switching to 'never'\n", value);
		return AST_CC_MONITOR_NEVER;
	}
}

static const char *agent_policy_to_str(enum ast_cc_agent_policies policy)
{
	switch (policy) {
	case AST_CC_AGENT_NEVER:
		return "never";
	case AST_CC_AGENT_NATIVE:
		return "native";
	case AST_CC_AGENT_GENERIC:
		return "generic";
	default:
		/* This should never happen... */
		return "";
	}
}

static const char *monitor_policy_to_str(enum ast_cc_monitor_policies policy)
{
	switch (policy) {
	case AST_CC_MONITOR_NEVER:
		return "never";
	case AST_CC_MONITOR_NATIVE:
		return "native";
	case AST_CC_MONITOR_GENERIC:
		return "generic";
	case AST_CC_MONITOR_ALWAYS:
		return "always";
	default:
		/* This should never happen... */
		return "";
	}
}
int ast_cc_get_param(struct ast_cc_config_params *params, const char * const name,
		char *buf, size_t buf_len)
{
	const char *value = NULL;

	if (!strcasecmp(name, "cc_callback_macro")) {
		value = ast_get_cc_callback_macro(params);
	} else if (!strcasecmp(name, "cc_callback_sub")) {
		value = ast_get_cc_callback_sub(params);
	} else if (!strcasecmp(name, "cc_agent_policy")) {
		value = agent_policy_to_str(ast_get_cc_agent_policy(params));
	} else if (!strcasecmp(name, "cc_monitor_policy")) {
		value = monitor_policy_to_str(ast_get_cc_monitor_policy(params));
	} else if (!strcasecmp(name, "cc_agent_dialstring")) {
		value = ast_get_cc_agent_dialstring(params);
	}
	if (value) {
		ast_copy_string(buf, value, buf_len);
		return 0;
	}

	/* The rest of these are all ints of some sort and require some
	 * snprintf-itude
	 */

	if (!strcasecmp(name, "cc_offer_timer")) {
		snprintf(buf, buf_len, "%u", ast_get_cc_offer_timer(params));
	} else if (!strcasecmp(name, "ccnr_available_timer")) {
		snprintf(buf, buf_len, "%u", ast_get_ccnr_available_timer(params));
	} else if (!strcasecmp(name, "ccbs_available_timer")) {
		snprintf(buf, buf_len, "%u", ast_get_ccbs_available_timer(params));
	} else if (!strcasecmp(name, "cc_max_agents")) {
		snprintf(buf, buf_len, "%u", ast_get_cc_max_agents(params));
	} else if (!strcasecmp(name, "cc_max_monitors")) {
		snprintf(buf, buf_len, "%u", ast_get_cc_max_monitors(params));
	} else if (!strcasecmp(name, "cc_recall_timer")) {
		snprintf(buf, buf_len, "%u", ast_get_cc_recall_timer(params));
	} else {
		ast_log(LOG_WARNING, "%s is not a valid CC parameter. Ignoring.\n", name);
		return -1;
	}

	return 0;
}

int ast_cc_set_param(struct ast_cc_config_params *params, const char * const name,
		const char * const value)
{
	unsigned int value_as_uint;
	if (!strcasecmp(name, "cc_agent_policy")) {
		return ast_set_cc_agent_policy(params, str_to_agent_policy(value));
	} else if (!strcasecmp(name, "cc_monitor_policy")) {
		return ast_set_cc_monitor_policy(params, str_to_monitor_policy(value));
	} else if (!strcasecmp(name, "cc_agent_dialstring")) {
		ast_set_cc_agent_dialstring(params, value);
	} else if (!strcasecmp(name, "cc_callback_macro")) {
		ast_set_cc_callback_macro(params, value);
		return 0;
	} else if (!strcasecmp(name, "cc_callback_sub")) {
		ast_set_cc_callback_sub(params, value);
		return 0;
	}

	if (sscanf(value, "%30u", &value_as_uint) != 1) {
		return -1;
	}

	if (!strcasecmp(name, "cc_offer_timer")) {
		ast_set_cc_offer_timer(params, value_as_uint);
	} else if (!strcasecmp(name, "ccnr_available_timer")) {
		ast_set_ccnr_available_timer(params, value_as_uint);
	} else if (!strcasecmp(name, "ccbs_available_timer")) {
		ast_set_ccbs_available_timer(params, value_as_uint);
	} else if (!strcasecmp(name, "cc_max_agents")) {
		ast_set_cc_max_agents(params, value_as_uint);
	} else if (!strcasecmp(name, "cc_max_monitors")) {
		ast_set_cc_max_monitors(params, value_as_uint);
	} else if (!strcasecmp(name, "cc_recall_timer")) {
		ast_set_cc_recall_timer(params, value_as_uint);
	} else {
		ast_log(LOG_WARNING, "%s is not a valid CC parameter. Ignoring.\n", name);
		return -1;
	}

	return 0;
}

int ast_cc_is_config_param(const char * const name)
{
	return (!strcasecmp(name, "cc_agent_policy") ||
				!strcasecmp(name, "cc_monitor_policy") ||
				!strcasecmp(name, "cc_offer_timer") ||
				!strcasecmp(name, "ccnr_available_timer") ||
				!strcasecmp(name, "ccbs_available_timer") ||
				!strcasecmp(name, "cc_max_agents") ||
				!strcasecmp(name, "cc_max_monitors") ||
				!strcasecmp(name, "cc_callback_macro") ||
				!strcasecmp(name, "cc_callback_sub") ||
				!strcasecmp(name, "cc_agent_dialstring") ||
				!strcasecmp(name, "cc_recall_timer"));
}

void ast_cc_copy_config_params(struct ast_cc_config_params *dest, const struct ast_cc_config_params *src)
{
	*dest = *src;
}

enum ast_cc_agent_policies ast_get_cc_agent_policy(struct ast_cc_config_params *config)
{
	return config->cc_agent_policy;
}

int ast_set_cc_agent_policy(struct ast_cc_config_params *config, enum ast_cc_agent_policies value)
{
	/* Screw C and its weak type checking for making me have to do this
	 * validation at runtime.
	 */
	if (value < AST_CC_AGENT_NEVER || value > AST_CC_AGENT_GENERIC) {
		return -1;
	}
	config->cc_agent_policy = value;
	return 0;
}

enum ast_cc_monitor_policies ast_get_cc_monitor_policy(struct ast_cc_config_params *config)
{
	return config->cc_monitor_policy;
}

int ast_set_cc_monitor_policy(struct ast_cc_config_params *config, enum ast_cc_monitor_policies value)
{
	/* Screw C and its weak type checking for making me have to do this
	 * validation at runtime.
	 */
	if (value < AST_CC_MONITOR_NEVER || value > AST_CC_MONITOR_ALWAYS) {
		return -1;
	}
	config->cc_monitor_policy = value;
	return 0;
}

unsigned int ast_get_cc_offer_timer(struct ast_cc_config_params *config)
{
	return config->cc_offer_timer;
}

void ast_set_cc_offer_timer(struct ast_cc_config_params *config, unsigned int value)
{
	/* 0 is an unreasonable value for any timer. Stick with the default */
	if (value == 0) {
		ast_log(LOG_WARNING, "0 is an invalid value for cc_offer_timer. Retaining value as %u\n", config->cc_offer_timer);
		return;
	}
	config->cc_offer_timer = value;
}

unsigned int ast_get_ccnr_available_timer(struct ast_cc_config_params *config)
{
	return config->ccnr_available_timer;
}

void ast_set_ccnr_available_timer(struct ast_cc_config_params *config, unsigned int value)
{
	/* 0 is an unreasonable value for any timer. Stick with the default */
	if (value == 0) {
		ast_log(LOG_WARNING, "0 is an invalid value for ccnr_available_timer. Retaining value as %u\n", config->ccnr_available_timer);
		return;
	}
	config->ccnr_available_timer = value;
}

unsigned int ast_get_cc_recall_timer(struct ast_cc_config_params *config)
{
	return config->cc_recall_timer;
}

void ast_set_cc_recall_timer(struct ast_cc_config_params *config, unsigned int value)
{
	/* 0 is an unreasonable value for any timer. Stick with the default */
	if (value == 0) {
		ast_log(LOG_WARNING, "0 is an invalid value for ccnr_available_timer. Retaining value as %u\n", config->cc_recall_timer);
		return;
	}
	config->cc_recall_timer = value;
}

unsigned int ast_get_ccbs_available_timer(struct ast_cc_config_params *config)
{
	return config->ccbs_available_timer;
}

void ast_set_ccbs_available_timer(struct ast_cc_config_params *config, unsigned int value)
{
	/* 0 is an unreasonable value for any timer. Stick with the default */
	if (value == 0) {
		ast_log(LOG_WARNING, "0 is an invalid value for ccbs_available_timer. Retaining value as %u\n", config->ccbs_available_timer);
		return;
	}
	config->ccbs_available_timer = value;
}

const char *ast_get_cc_agent_dialstring(struct ast_cc_config_params *config)
{
	return config->cc_agent_dialstring;
}

void ast_set_cc_agent_dialstring(struct ast_cc_config_params *config, const char *const value)
{
	if (ast_strlen_zero(value)) {
		config->cc_agent_dialstring[0] = '\0';
	} else {
		ast_copy_string(config->cc_agent_dialstring, value, sizeof(config->cc_agent_dialstring));
	}
}

unsigned int ast_get_cc_max_agents(struct ast_cc_config_params *config)
{
	return config->cc_max_agents;
}

void ast_set_cc_max_agents(struct ast_cc_config_params *config, unsigned int value)
{
	config->cc_max_agents = value;
}

unsigned int ast_get_cc_max_monitors(struct ast_cc_config_params *config)
{
	return config->cc_max_monitors;
}

void ast_set_cc_max_monitors(struct ast_cc_config_params *config, unsigned int value)
{
	config->cc_max_monitors = value;
}

const char *ast_get_cc_callback_macro(struct ast_cc_config_params *config)
{
	return config->cc_callback_macro;
}

const char *ast_get_cc_callback_sub(struct ast_cc_config_params *config)
{
	return config->cc_callback_sub;
}

void ast_set_cc_callback_macro(struct ast_cc_config_params *config, const char * const value)
{
	ast_log(LOG_WARNING, "Usage of cc_callback_macro is deprecated.  Please use cc_callback_sub instead.\n");
	if (ast_strlen_zero(value)) {
		config->cc_callback_macro[0] = '\0';
	} else {
		ast_copy_string(config->cc_callback_macro, value, sizeof(config->cc_callback_macro));
	}
}

void ast_set_cc_callback_sub(struct ast_cc_config_params *config, const char * const value)
{
	if (ast_strlen_zero(value)) {
		config->cc_callback_sub[0] = '\0';
	} else {
		ast_copy_string(config->cc_callback_sub, value, sizeof(config->cc_callback_sub));
	}
}

static int cc_publish(struct stasis_message_type *message_type, int core_id, struct ast_json *extras)
{
	struct ast_json *blob;
	struct ast_json_payload *payload;
	struct stasis_message *message;

	if (!message_type) {
		return -1;
	}

	blob = ast_json_pack("{s: i}",
		"core_id", core_id);
	if (!blob) {
		return -1;
	}

	if (extras) {
		ast_json_object_update(blob, extras);
	}

	payload = ast_json_payload_create(blob);
	ast_json_unref(blob);

	if (!payload) {
		return -1;
	}

	message = stasis_message_create(message_type, payload);
	ao2_ref(payload, -1);

	if (!message) {
		return -1;
	}

	stasis_publish(ast_system_topic(), message);
	ao2_ref(message, -1);

	return 0;
}

static void cc_publish_available(int core_id, const char *callee, const char *service)
{
	struct ast_json *extras;

	extras = ast_json_pack("{s: s, s: s}",
		"callee", callee,
		"service", service);

	cc_publish(ast_cc_available_type(), core_id, extras);
	ast_json_unref(extras);
}

static void cc_publish_offertimerstart(int core_id, const char *caller, unsigned int expires)
{
	struct ast_json *extras;

	extras = ast_json_pack("{s: s, s: i}",
		"caller", caller,
		"expires", expires);

	cc_publish(ast_cc_offertimerstart_type(), core_id, extras);
	ast_json_unref(extras);
}

static void cc_publish_requested(int core_id, const char *caller, const char *callee)
{
	struct ast_json *extras;

	extras = ast_json_pack("{s: s, s: s}",
		"caller", caller,
		"callee", callee);

	cc_publish(ast_cc_requested_type(), core_id, extras);
	ast_json_unref(extras);
}

static void cc_publish_requestacknowledged(int core_id, const char *caller)
{
	struct ast_json *extras;

	extras = ast_json_pack("{s: s}",
		"caller", caller);

	cc_publish(ast_cc_requestacknowledged_type(), core_id, extras);
	ast_json_unref(extras);
}

static void cc_publish_callerstopmonitoring(int core_id, const char *caller)
{
	struct ast_json *extras;

	extras = ast_json_pack("{s: s}",
		"caller", caller);

	cc_publish(ast_cc_callerstopmonitoring_type(), core_id, extras);
	ast_json_unref(extras);
}

static void cc_publish_callerstartmonitoring(int core_id, const char *caller)
{
	struct ast_json *extras;

	extras = ast_json_pack("{s: s}",
		"caller", caller);

	cc_publish(ast_cc_callerstartmonitoring_type(), core_id, extras);
	ast_json_unref(extras);
}

static void cc_publish_callerrecalling(int core_id, const char *caller)
{
	struct ast_json *extras;

	extras = ast_json_pack("{s: s}",
		"caller", caller);

	cc_publish(ast_cc_callerrecalling_type(), core_id, extras);
	ast_json_unref(extras);
}

static void cc_publish_recallcomplete(int core_id, const char *caller)
{
	struct ast_json *extras;

	extras = ast_json_pack("{s: s}",
		"caller", caller);

	cc_publish(ast_cc_recallcomplete_type(), core_id, extras);
	ast_json_unref(extras);
}

static void cc_publish_failure(int core_id, const char *caller, const char *reason)
{
	struct ast_json *extras;

	extras = ast_json_pack("{s: s, s: s}",
		"caller", caller,
		"reason", reason);

	cc_publish(ast_cc_failure_type(), core_id, extras);
	ast_json_unref(extras);
}

static void cc_publish_monitorfailed(int core_id, const char *callee)
{
	struct ast_json *extras;

	extras = ast_json_pack("{s: s}",
		"callee", callee);

	cc_publish(ast_cc_monitorfailed_type(), core_id, extras);
	ast_json_unref(extras);
}

struct cc_monitor_backend {
	AST_LIST_ENTRY(cc_monitor_backend) next;
	const struct ast_cc_monitor_callbacks *callbacks;
};

AST_RWLIST_HEAD_STATIC(cc_monitor_backends, cc_monitor_backend);

int ast_cc_monitor_register(const struct ast_cc_monitor_callbacks *callbacks)
{
	struct cc_monitor_backend *backend = ast_calloc(1, sizeof(*backend));

	if (!backend) {
		return -1;
	}

	backend->callbacks = callbacks;

	AST_RWLIST_WRLOCK(&cc_monitor_backends);
	AST_RWLIST_INSERT_TAIL(&cc_monitor_backends, backend, next);
	AST_RWLIST_UNLOCK(&cc_monitor_backends);
	return 0;
}

static const struct ast_cc_monitor_callbacks *find_monitor_callbacks(const char * const type)
{
	struct cc_monitor_backend *backend;
	const struct ast_cc_monitor_callbacks *callbacks = NULL;

	AST_RWLIST_RDLOCK(&cc_monitor_backends);
	AST_RWLIST_TRAVERSE(&cc_monitor_backends, backend, next) {
		if (!strcmp(backend->callbacks->type, type)) {
			ast_log_dynamic_level(cc_logger_level, "Returning monitor backend %s\n", backend->callbacks->type);
			callbacks = backend->callbacks;
			break;
		}
	}
	AST_RWLIST_UNLOCK(&cc_monitor_backends);
	return callbacks;
}

void ast_cc_monitor_unregister(const struct ast_cc_monitor_callbacks *callbacks)
{
	struct cc_monitor_backend *backend;
	AST_RWLIST_WRLOCK(&cc_monitor_backends);
	AST_RWLIST_TRAVERSE_SAFE_BEGIN(&cc_monitor_backends, backend, next) {
		if (backend->callbacks == callbacks) {
			AST_RWLIST_REMOVE_CURRENT(next);
			ast_free(backend);
			break;
		}
	}
	AST_RWLIST_TRAVERSE_SAFE_END;
	AST_RWLIST_UNLOCK(&cc_monitor_backends);
}

struct cc_agent_backend {
	AST_LIST_ENTRY(cc_agent_backend) next;
	const struct ast_cc_agent_callbacks *callbacks;
};

AST_RWLIST_HEAD_STATIC(cc_agent_backends, cc_agent_backend);

int ast_cc_agent_register(const struct ast_cc_agent_callbacks *callbacks)
{
	struct cc_agent_backend *backend = ast_calloc(1, sizeof(*backend));

	if (!backend) {
		return -1;
	}

	backend->callbacks = callbacks;
	AST_RWLIST_WRLOCK(&cc_agent_backends);
	AST_RWLIST_INSERT_TAIL(&cc_agent_backends, backend, next);
	AST_RWLIST_UNLOCK(&cc_agent_backends);
	return 0;
}

void ast_cc_agent_unregister(const struct ast_cc_agent_callbacks *callbacks)
{
	struct cc_agent_backend *backend;
	AST_RWLIST_WRLOCK(&cc_agent_backends);
	AST_RWLIST_TRAVERSE_SAFE_BEGIN(&cc_agent_backends, backend, next) {
		if (backend->callbacks == callbacks) {
			AST_RWLIST_REMOVE_CURRENT(next);
			ast_free(backend);
			break;
		}
	}
	AST_RWLIST_TRAVERSE_SAFE_END;
	AST_RWLIST_UNLOCK(&cc_agent_backends);
}

static const struct ast_cc_agent_callbacks *find_agent_callbacks(struct ast_channel *chan)
{
	struct cc_agent_backend *backend;
	const struct ast_cc_agent_callbacks *callbacks = NULL;
	struct ast_cc_config_params *cc_params;
	char type[32];

	cc_params = ast_channel_get_cc_config_params(chan);
	if (!cc_params) {
		return NULL;
	}
	switch (ast_get_cc_agent_policy(cc_params)) {
	case AST_CC_AGENT_GENERIC:
		ast_copy_string(type, "generic", sizeof(type));
		break;
	case AST_CC_AGENT_NATIVE:
		ast_channel_get_cc_agent_type(chan, type, sizeof(type));
		break;
	default:
		ast_log_dynamic_level(cc_logger_level, "Not returning agent callbacks since this channel is configured not to have a CC agent\n");
		return NULL;
	}

	AST_RWLIST_RDLOCK(&cc_agent_backends);
	AST_RWLIST_TRAVERSE(&cc_agent_backends, backend, next) {
		if (!strcmp(backend->callbacks->type, type)) {
			ast_log_dynamic_level(cc_logger_level, "Returning agent backend %s\n", backend->callbacks->type);
			callbacks = backend->callbacks;
			break;
		}
	}
	AST_RWLIST_UNLOCK(&cc_agent_backends);
	return callbacks;
}

/*!
 * \internal
 * \brief Determine if the given device state is considered available by generic CCSS.
 * \since 1.8
 *
 * \param state Device state to test.
 *
 * \return TRUE if the given device state is considered available by generic CCSS.
 */
static int cc_generic_is_device_available(enum ast_device_state state)
{
	return state == AST_DEVICE_NOT_INUSE || state == AST_DEVICE_UNKNOWN;
}

static int cc_generic_monitor_request_cc(struct ast_cc_monitor *monitor, int *available_timer_id);
static int cc_generic_monitor_suspend(struct ast_cc_monitor *monitor);
static int cc_generic_monitor_unsuspend(struct ast_cc_monitor *monitor);
static int cc_generic_monitor_cancel_available_timer(struct ast_cc_monitor *monitor, int *sched_id);
static void cc_generic_monitor_destructor(void *private_data);

static struct ast_cc_monitor_callbacks generic_monitor_cbs = {
	.type = "generic",
	.request_cc = cc_generic_monitor_request_cc,
	.suspend = cc_generic_monitor_suspend,
	.unsuspend = cc_generic_monitor_unsuspend,
	.cancel_available_timer = cc_generic_monitor_cancel_available_timer,
	.destructor = cc_generic_monitor_destructor,
};

struct ao2_container *generic_monitors;

struct generic_monitor_instance {
	int core_id;
	int is_suspended;
	int monitoring;
	AST_LIST_ENTRY(generic_monitor_instance) next;
};

struct generic_monitor_instance_list {
	const char *device_name;
	enum ast_device_state current_state;
	/* If there are multiple instances monitoring the
	 * same device and one should fail, we need to know
	 * whether to signal that the device can be recalled.
	 * The problem is that the device state is not enough
	 * to check. If a caller has requested CCNR, then the
	 * fact that the device is available does not indicate
	 * that the device is ready to be recalled. Instead, as
	 * soon as one instance of the monitor becomes available
	 * for a recall, we mark the entire list as being fit
	 * for recall. If a CCNR request comes in, then we will
	 * have to mark the list as unfit for recall since this
	 * is a clear indicator that the person at the monitored
	 * device has gone away and is actuall not fit to be
	 * recalled
	 */
	int fit_for_recall;
	struct stasis_subscription *sub;
	AST_LIST_HEAD_NOLOCK(, generic_monitor_instance) list;
};

/*!
 * \brief private data for generic device monitor
 */
struct generic_monitor_pvt {
	/*!
	 * We need the device name during destruction so we
	 * can find the appropriate item to destroy.
	 */
	const char *device_name;
	/*!
	 * We need the core ID for similar reasons. Once we
	 * find the appropriate item in our ao2_container, we
	 * need to remove the appropriate cc_monitor from the
	 * list of monitors.
	 */
	int core_id;
};

AO2_STRING_FIELD_HASH_FN(generic_monitor_instance_list, device_name)
AO2_STRING_FIELD_CMP_FN(generic_monitor_instance_list, device_name)

static struct generic_monitor_instance_list *find_generic_monitor_instance_list(const char * const device_name)
{
	struct generic_monitor_instance_list finder = {0};
	char *uppertech = ast_strdupa(device_name);
	ast_tech_to_upper(uppertech);
	finder.device_name = uppertech;

	return ao2_t_find(generic_monitors, &finder, OBJ_POINTER, "Finding generic monitor instance list");
}

static void generic_monitor_instance_list_destructor(void *obj)
{
	struct generic_monitor_instance_list *generic_list = obj;
	struct generic_monitor_instance *generic_instance;

	generic_list->sub = stasis_unsubscribe(generic_list->sub);
	while ((generic_instance = AST_LIST_REMOVE_HEAD(&generic_list->list, next))) {
		ast_free(generic_instance);
	}
	ast_free((char *)generic_list->device_name);
}

static void generic_monitor_devstate_cb(void *userdata, struct stasis_subscription *sub, struct stasis_message *msg);
static struct generic_monitor_instance_list *create_new_generic_list(struct ast_cc_monitor *monitor)
{
	struct generic_monitor_instance_list *generic_list = ao2_t_alloc(sizeof(*generic_list),
			generic_monitor_instance_list_destructor, "allocate generic monitor instance list");
	char * device_name;
	struct stasis_topic *device_specific_topic;

	if (!generic_list) {
		return NULL;
	}

	if (!(device_name = ast_strdup(monitor->interface->device_name))) {
		cc_unref(generic_list, "Failed to strdup the monitor's device name");
		return NULL;
	}
	ast_tech_to_upper(device_name);
	generic_list->device_name = device_name;

	device_specific_topic = ast_device_state_topic(device_name);
	if (!device_specific_topic) {
		return NULL;
	}

	if (!(generic_list->sub = stasis_subscribe(device_specific_topic, generic_monitor_devstate_cb, NULL))) {
		cc_unref(generic_list, "Failed to subscribe to device state");
		return NULL;
	}
	stasis_subscription_accept_message_type(generic_list->sub, ast_device_state_message_type());
	stasis_subscription_set_filter(generic_list->sub, STASIS_SUBSCRIPTION_FILTER_SELECTIVE);
	generic_list->current_state = ast_device_state(monitor->interface->device_name);
	ao2_t_link(generic_monitors, generic_list, "linking new generic monitor instance list");
	return generic_list;
}

static int generic_monitor_devstate_tp_cb(void *data)
{
	RAII_VAR(struct ast_device_state_message *, dev_state, data, ao2_cleanup);
	enum ast_device_state new_state = dev_state->state;
	enum ast_device_state previous_state;
	struct generic_monitor_instance_list *generic_list;
	struct generic_monitor_instance *generic_instance;

	if (!(generic_list = find_generic_monitor_instance_list(dev_state->device))) {
		/* The most likely cause for this is that we destroyed the monitor in the
		 * time between subscribing to its device state and the time this executes.
		 * Not really a big deal.
		 */
		return 0;
	}

	if (generic_list->current_state == new_state) {
		/* The device state hasn't actually changed, so we don't really care */
		cc_unref(generic_list, "Kill reference of generic list in devstate taskprocessor callback");
		return 0;
	}

	previous_state = generic_list->current_state;
	generic_list->current_state = new_state;

	if (cc_generic_is_device_available(new_state) &&
			(previous_state == AST_DEVICE_INUSE || previous_state == AST_DEVICE_UNAVAILABLE ||
			 previous_state == AST_DEVICE_BUSY)) {
		AST_LIST_TRAVERSE(&generic_list->list, generic_instance, next) {
			if (!generic_instance->is_suspended && generic_instance->monitoring) {
				generic_instance->monitoring = 0;
				generic_list->fit_for_recall = 1;
				ast_cc_monitor_callee_available(generic_instance->core_id, "Generic monitored party has become available");
				break;
			}
		}
	}
	cc_unref(generic_list, "Kill reference of generic list in devstate taskprocessor callback");
	return 0;
}

static void generic_monitor_devstate_cb(void *userdata, struct stasis_subscription *sub, struct stasis_message *msg)
{
	/* Wow, it's cool that we've picked up on a state change, but we really want
	 * the actual work to be done in the core's taskprocessor execution thread
	 * so that all monitor operations can be serialized. Locks?! We don't need
	 * no steenkin' locks!
	 */
	struct ast_device_state_message *dev_state;
	if (ast_device_state_message_type() != stasis_message_type(msg)) {
		return;
	}

	dev_state = stasis_message_data(msg);
	if (dev_state->eid) {
		/* ignore non-aggregate states */
		return;
	}

	ao2_t_ref(dev_state, +1, "Bumping dev_state ref for cc_core_taskprocessor");
	if (ast_taskprocessor_push(cc_core_taskprocessor, generic_monitor_devstate_tp_cb, dev_state)) {
		ao2_cleanup(dev_state);
		return;
	}
}

int ast_cc_available_timer_expire(const void *data)
{
	struct ast_cc_monitor *monitor = (struct ast_cc_monitor *) data;
	int res;
	monitor->available_timer_id = -1;
	res = ast_cc_monitor_failed(monitor->core_id, monitor->interface->device_name, "Available timer expired for monitor");
	cc_unref(monitor, "Unref reference from scheduler\n");
	return res;
}

static int cc_generic_monitor_request_cc(struct ast_cc_monitor *monitor, int *available_timer_id)
{
	struct generic_monitor_instance_list *generic_list;
	struct generic_monitor_instance *generic_instance;
	struct generic_monitor_pvt *gen_mon_pvt;
	enum ast_cc_service_type service = monitor->service_offered;
	int when;

	/* First things first. Native channel drivers will have their private data allocated
	 * at the time that they tell the core that they can offer CC. Generic is quite a bit
	 * different, and we wait until this point to allocate our private data.
	 */
	if (!(gen_mon_pvt = ast_calloc(1, sizeof(*gen_mon_pvt)))) {
		return -1;
	}

	if (!(gen_mon_pvt->device_name = ast_strdup(monitor->interface->device_name))) {
		ast_free(gen_mon_pvt);
		return -1;
	}

	gen_mon_pvt->core_id = monitor->core_id;

	monitor->private_data = gen_mon_pvt;

	if (!(generic_list = find_generic_monitor_instance_list(monitor->interface->device_name))) {
		if (!(generic_list = create_new_generic_list(monitor))) {
			return -1;
		}
	}

	if (!(generic_instance = ast_calloc(1, sizeof(*generic_instance)))) {
		/* The generic monitor destructor will take care of the appropriate
		 * deallocations
		 */
		cc_unref(generic_list, "Generic monitor instance failed to allocate");
		return -1;
	}
	generic_instance->core_id = monitor->core_id;
	generic_instance->monitoring = 1;
	AST_LIST_INSERT_TAIL(&generic_list->list, generic_instance, next);
	when = service == AST_CC_CCBS ? ast_get_ccbs_available_timer(monitor->interface->config_params) :
		ast_get_ccnr_available_timer(monitor->interface->config_params);

	*available_timer_id = ast_sched_add(cc_sched_context, when * 1000,
			ast_cc_available_timer_expire, cc_ref(monitor, "Give the scheduler a monitor reference"));
	if (*available_timer_id == -1) {
		cc_unref(monitor, "Failed to schedule available timer. (monitor)");
		cc_unref(generic_list, "Failed to schedule available timer. (generic_list)");
		return -1;
	}
	/* If the new instance was created as CCNR, then that means this device is not currently
	 * fit for recall even if it previously was.
	 */
	if (service == AST_CC_CCNR || service == AST_CC_CCNL) {
		generic_list->fit_for_recall = 0;
	}
	ast_cc_monitor_request_acked(monitor->core_id, "Generic monitor for %s subscribed to device state.",
			monitor->interface->device_name);
	cc_unref(generic_list, "Finished with monitor instance reference in request cc callback");
	return 0;
}

static int cc_generic_monitor_suspend(struct ast_cc_monitor *monitor)
{
	struct generic_monitor_instance_list *generic_list;
	struct generic_monitor_instance *generic_instance;
	enum ast_device_state state = ast_device_state(monitor->interface->device_name);

	if (!(generic_list = find_generic_monitor_instance_list(monitor->interface->device_name))) {
		return -1;
	}

	/* First we need to mark this particular monitor as being suspended. */
	AST_LIST_TRAVERSE(&generic_list->list, generic_instance, next) {
		if (generic_instance->core_id == monitor->core_id) {
			generic_instance->is_suspended = 1;
			break;
		}
	}

	/* If the device being suspended is currently in use, then we don't need to
	 * take any further actions
	 */
	if (!cc_generic_is_device_available(state)) {
		cc_unref(generic_list, "Device is in use. Nothing to do. Unref generic list.");
		return 0;
	}

	/* If the device is not in use, though, then it may be possible to report the
	 * device's availability using a different monitor which is monitoring the
	 * same device
	 */

	AST_LIST_TRAVERSE(&generic_list->list, generic_instance, next) {
		if (!generic_instance->is_suspended) {
			ast_cc_monitor_callee_available(generic_instance->core_id, "Generic monitored party has become available");
			break;
		}
	}
	cc_unref(generic_list, "Done with generic list in suspend callback");
	return 0;
}

static int cc_generic_monitor_unsuspend(struct ast_cc_monitor *monitor)
{
	struct generic_monitor_instance *generic_instance;
	struct generic_monitor_instance_list *generic_list = find_generic_monitor_instance_list(monitor->interface->device_name);
	enum ast_device_state state = ast_device_state(monitor->interface->device_name);

	if (!generic_list) {
		return -1;
	}
	/* If the device is currently available, we can immediately announce
	 * its availability
	 */
	if (cc_generic_is_device_available(state)) {
		ast_cc_monitor_callee_available(monitor->core_id, "Generic monitored party has become available");
	}

	/* In addition, we need to mark this generic_monitor_instance as not being suspended anymore */
	AST_LIST_TRAVERSE(&generic_list->list, generic_instance, next) {
		if (generic_instance->core_id == monitor->core_id) {
			generic_instance->is_suspended = 0;
			generic_instance->monitoring = 1;
			break;
		}
	}
	cc_unref(generic_list, "Done with generic list in cc_generic_monitor_unsuspend");
	return 0;
}

static int cc_generic_monitor_cancel_available_timer(struct ast_cc_monitor *monitor, int *sched_id)
{
	ast_assert(sched_id != NULL);

	if (*sched_id == -1) {
		return 0;
	}

	ast_log_dynamic_level(cc_logger_level, "Core %d: Canceling generic monitor available timer for monitor %s\n",
			monitor->core_id, monitor->interface->device_name);
	if (!ast_sched_del(cc_sched_context, *sched_id)) {
		cc_unref(monitor, "Remove scheduler's reference to the monitor");
	}
	*sched_id = -1;
	return 0;
}

static void cc_generic_monitor_destructor(void *private_data)
{
	struct generic_monitor_pvt *gen_mon_pvt = private_data;
	struct generic_monitor_instance_list *generic_list;
	struct generic_monitor_instance *generic_instance;

	if (!private_data) {
		/* If the private data is NULL, that means that the monitor hasn't even
		 * been created yet, but that the destructor was called. While this sort
		 * of behavior is useful for native monitors, with a generic one, there is
		 * nothing in particular to do.
		 */
		return;
	}

	ast_log_dynamic_level(cc_logger_level, "Core %d: Destroying generic monitor %s\n",
			gen_mon_pvt->core_id, gen_mon_pvt->device_name);

	if (!(generic_list = find_generic_monitor_instance_list(gen_mon_pvt->device_name))) {
		/* If there's no generic list, that means that the monitor is being destroyed
		 * before we actually got to request CC. Not a biggie. Same in the situation
		 * below if the list traversal should complete without finding an entry.
		 */
		ast_free((char *)gen_mon_pvt->device_name);
		ast_free(gen_mon_pvt);
		return;
	}

	AST_LIST_TRAVERSE_SAFE_BEGIN(&generic_list->list, generic_instance, next) {
		if (generic_instance->core_id == gen_mon_pvt->core_id) {
			AST_LIST_REMOVE_CURRENT(next);
			ast_free(generic_instance);
			break;
		}
	}
	AST_LIST_TRAVERSE_SAFE_END;

	if (AST_LIST_EMPTY(&generic_list->list)) {
		/* No more monitors with this device name exist. Time to unlink this
		 * list from the container
		 */
		ao2_t_unlink(generic_monitors, generic_list, "Generic list is empty. Unlink it from the container");
	} else {
		/* There are still instances for this particular device. The situation
		 * may be that we were attempting a CC recall and a failure occurred, perhaps
		 * on the agent side. If a failure happens here and the device being monitored
		 * is available, then we need to signal on the first unsuspended instance that
		 * the device is available for recall.
		 */

		/* First things first. We don't even want to consider this action if
		 * the device in question isn't available right now.
		 */
		if (generic_list->fit_for_recall
			&& cc_generic_is_device_available(generic_list->current_state)) {
			AST_LIST_TRAVERSE(&generic_list->list, generic_instance, next) {
				if (!generic_instance->is_suspended && generic_instance->monitoring) {
					ast_cc_monitor_callee_available(generic_instance->core_id, "Signaling generic monitor "
							"availability due to other instance's failure.");
					break;
				}
			}
		}
	}
	cc_unref(generic_list, "Done with generic list in generic monitor destructor");
	ast_free((char *)gen_mon_pvt->device_name);
	ast_free(gen_mon_pvt);
}

static void cc_interface_destroy(void *data)
{
	struct ast_cc_interface *interface = data;
	ast_log_dynamic_level(cc_logger_level, "Destroying cc interface %s\n", interface->device_name);
	ast_cc_config_params_destroy(interface->config_params);
}

/*!
 * \brief Data regarding an extension monitor's child's dialstrings
 *
 * \details
 * In developing CCSS, we had most aspects of its operation finished,
 * but there was one looming problem that we had failed to get right.
 * In our design document, we stated that when a CC recall occurs, all
 * endpoints that had been dialed originally would be called back.
 * Unfortunately, our implementation only allowed for devices which had
 * active monitors to inhabit the CC_INTERFACES channel variable, thus
 * making the automated recall only call monitored devices.
 *
 * Devices that were not CC-capable, or devices which failed CC at some
 * point during the process would not make it into the CC_INTERFACES
 * channel variable. This struct is meant as a remedy for the problem.
 */
struct extension_child_dialstring {
	/*!
	 * \brief the original dialstring used to call a particular device
	 *
	 * \details
	 * When someone dials a particular endpoint, the dialstring used in
	 * the dialplan is copied into this buffer. What's important here is
	 * that this is the ORIGINAL dialstring, not the dialstring saved on
	 * a device monitor. The dialstring on a device monitor is what should
	 * be used when recalling that device. The two dialstrings may not be
	 * the same.
	 *
	 * By keeping a copy of the original dialstring used, we can fall back
	 * to using it if the device either does not ever offer CC or if the
	 * device at some point fails for some reason, such as a timer expiration.
	 */
	char original_dialstring[AST_CHANNEL_NAME];
	/*!
	 * \brief The name of the device being dialed
	 *
	 * \details
	 * This serves mainly as a key when searching for a particular dialstring.
	 * For instance, let's say that we have called device SIP/400\@somepeer. This
	 * device offers call completion, but then due to some unforeseen circumstance,
	 * this device backs out and makes CC unavailable. When that happens, we need
	 * to find the dialstring that corresponds to that device, and we use the
	 * stored device name as a way to find it.
	 *
	 * \note There is one particular case where the device name stored here
	 * will be empty. This is the case where we fail to request a channel, but we
	 * still can make use of generic call completion. In such a case, since we never
	 * were able to request the channel, we can't find what its device name is. In
	 * this case, however, it is not important because the dialstring is guaranteed
	 * to be the same both here and in the device monitor.
	 */
	char device_name[AST_CHANNEL_NAME];
	/*!
	 * \brief Is this structure valid for use in CC_INTERFACES?
	 *
	 * \details
	 * When this structure is first created, all information stored here is planned
	 * to be used, so we set the is_valid flag. However, if a device offers call
	 * completion, it will potentially have its own dialstring to use for the recall,
	 * so we find this structure and clear the is_valid flag. By clearing the is_valid
	 * flag, we won't try to populate the CC_INTERFACES variable with the dialstring
	 * stored in this struct. Now, if later, the device which had offered CC should fail,
	 * perhaps due to a timer expiration, then we need to re-set the is_valid flag. This
	 * way, we still will end up placing a call to the device again, and the dialstring
	 * used will be the same as was originally used.
	 */
	int is_valid;
	AST_LIST_ENTRY(extension_child_dialstring) next;
};

/*!
 * \brief Private data for an extension monitor
 */
struct extension_monitor_pvt {
	AST_LIST_HEAD_NOLOCK(, extension_child_dialstring) child_dialstrings;
};

static void cc_extension_monitor_destructor(void *private_data)
{
	struct extension_monitor_pvt *extension_pvt = private_data;
	struct extension_child_dialstring *child_dialstring;

	/* This shouldn't be possible, but I'm paranoid */
	if (!extension_pvt) {
		return;
	}

	while ((child_dialstring = AST_LIST_REMOVE_HEAD(&extension_pvt->child_dialstrings, next))) {
		ast_free(child_dialstring);
	}
	ast_free(extension_pvt);
}

static void cc_monitor_destroy(void *data)
{
	struct ast_cc_monitor *monitor = data;
	/* During the monitor creation process, it is possible for this
	 * function to be called prior to when callbacks are assigned
	 * to the monitor. Also, extension monitors do not have callbacks
	 * assigned to them, so we wouldn't want to segfault when we try
	 * to destroy one of them.
	 */
	ast_log_dynamic_level(cc_logger_level, "Core %d: Calling destructor for monitor %s\n",
			monitor->core_id, monitor->interface->device_name);
	if (monitor->interface->monitor_class == AST_CC_EXTENSION_MONITOR) {
		cc_extension_monitor_destructor(monitor->private_data);
	}
	if (monitor->callbacks) {
		monitor->callbacks->destructor(monitor->private_data);
	}
	cc_unref(monitor->interface, "Unreffing tree's reference to interface");
	ast_free(monitor->dialstring);
}

static void cc_interface_tree_destroy(void *data)
{
	struct cc_monitor_tree *cc_interface_tree = data;
	struct ast_cc_monitor *monitor;
	while ((monitor = AST_LIST_REMOVE_HEAD(cc_interface_tree, next))) {
		if (monitor->callbacks) {
			monitor->callbacks->cancel_available_timer(monitor, &monitor->available_timer_id);
		}
		cc_unref(monitor, "Destroying all monitors");
	}
	AST_LIST_HEAD_DESTROY(cc_interface_tree);
}

/*!
 * This counter is used for assigning unique ids
 * to CC-enabled dialed interfaces.
 */
static int dialed_cc_interface_counter;

/*!
 * \internal
 * \brief data stored in CC datastore
 *
 * The datastore creates a list of interfaces that were
 * dialed, including both extensions and devices. In addition
 * to the intrinsic data of the tree, some extra information
 * is needed for use by app_dial.
 */
struct dialed_cc_interfaces {
	/*!
	 * This value serves a dual-purpose. When dial starts, if the
	 * dialed_cc_interfaces datastore currently exists on the calling
	 * channel, then the dial_parent_id will serve as a means of
	 * letting the new extension cc_monitor we create know
	 * who his parent is. This value will be the extension
	 * cc_monitor that dialed the local channel that resulted
	 * in the new Dial app being called.
	 *
	 * In addition, once an extension cc_monitor is created,
	 * the dial_parent_id will be changed to the id of that newly
	 * created interface. This way, device interfaces created from
	 * receiving AST_CONTROL_CC frames can use this field to determine
	 * who their parent extension interface should be.
	 */
	unsigned int dial_parent_id;
	/*!
	 * Identifier for the potential CC request that may be made
	 * based on this call. Even though an instance of the core may
	 * not be made (since the caller may not request CC), we allocate
	 * a new core_id at the beginning of the call so that recipient
	 * channel drivers can have the information handy just in case
	 * the caller does end up requesting CC.
	 */
	int core_id;
	/*!
	 * When a new Dial application is started, and the datastore
	 * already exists on the channel, we can determine if we
	 * should be adding any new interface information to tree.
	 */
	char ignore;
	/*!
	 * When it comes time to offer CC to the caller, we only want to offer
	 * it to the original incoming channel. For nested Dials and outbound
	 * channels, it is incorrect to attempt such a thing. This flag indicates
	 * if the channel to which this datastore is attached may be legally
	 * offered CC when the call is finished.
	 */
	char is_original_caller;
	/*!
	 * Reference-counted "tree" of interfaces.
	 */
	struct cc_monitor_tree *interface_tree;
};

/*!
 * \internal
 * \brief Destructor function for cc_interfaces datastore
 *
 * This function will free the actual datastore and drop
 * the refcount for the monitor tree by one. In cases
 * where CC can actually be used, this unref will not
 * result in the destruction of the monitor tree, because
 * the CC core will still have a reference.
 *
 * \param data The dialed_cc_interfaces struct to destroy
 */
static void dialed_cc_interfaces_destroy(void *data)
{
	struct dialed_cc_interfaces *cc_interfaces = data;
	cc_unref(cc_interfaces->interface_tree, "Unref dial's ref to monitor tree");
	ast_free(cc_interfaces);
}

/*!
 * \internal
 * \brief Duplicate callback for cc_interfaces datastore
 *
 * Integers are copied by value, but the monitor tree
 * is done via a shallow copy and a bump of the refcount.
 * This way, sub-Dials will be appending interfaces onto
 * the same list as this call to Dial.
 *
 * \param data The old dialed_cc_interfaces we want to copy
 * \retval NULL Could not allocate memory for new dialed_cc_interfaces
 * \retval non-NULL The new copy of the dialed_cc_interfaces
 */
static void *dialed_cc_interfaces_duplicate(void *data)
{
	struct dialed_cc_interfaces *old_cc_interfaces = data;
	struct dialed_cc_interfaces *new_cc_interfaces = ast_calloc(1, sizeof(*new_cc_interfaces));
	if (!new_cc_interfaces) {
		return NULL;
	}
	new_cc_interfaces->ignore = old_cc_interfaces->ignore;
	new_cc_interfaces->dial_parent_id = old_cc_interfaces->dial_parent_id;
	new_cc_interfaces->is_original_caller = 0;
	cc_ref(old_cc_interfaces->interface_tree, "New ref due to duplication of monitor tree");
	new_cc_interfaces->core_id = old_cc_interfaces->core_id;
	new_cc_interfaces->interface_tree = old_cc_interfaces->interface_tree;
	return new_cc_interfaces;
}

/*!
 * \internal
 * \brief information regarding the dialed_cc_interfaces datastore
 *
 * The dialed_cc_interfaces datastore is responsible for keeping track
 * of what CC-enabled interfaces have been dialed by the caller. For
 * more information regarding the actual structure of the tree, see
 * the documentation provided in include/asterisk/ccss.h
 */
static const struct ast_datastore_info dialed_cc_interfaces_info = {
	.type = "Dial CC Interfaces",
	.duplicate = dialed_cc_interfaces_duplicate,
	.destroy = dialed_cc_interfaces_destroy,
};

static struct extension_monitor_pvt *extension_monitor_pvt_init(void)
{
	struct extension_monitor_pvt *ext_pvt = ast_calloc(1, sizeof(*ext_pvt));
	if (!ext_pvt) {
		return NULL;
	}
	AST_LIST_HEAD_INIT_NOLOCK(&ext_pvt->child_dialstrings);
	return ext_pvt;
}

void ast_cc_extension_monitor_add_dialstring(struct ast_channel *incoming, const char * const dialstring, const char * const device_name)
{
	struct ast_datastore *cc_datastore;
	struct dialed_cc_interfaces *cc_interfaces;
	struct ast_cc_monitor *monitor;
	struct extension_monitor_pvt *extension_pvt;
	struct extension_child_dialstring *child_dialstring;
	struct cc_monitor_tree *interface_tree;
	int id;

	ast_channel_lock(incoming);
	if (!(cc_datastore = ast_channel_datastore_find(incoming, &dialed_cc_interfaces_info, NULL))) {
		ast_channel_unlock(incoming);
		return;
	}

	cc_interfaces = cc_datastore->data;
	interface_tree = cc_interfaces->interface_tree;
	id = cc_interfaces->dial_parent_id;
	ast_channel_unlock(incoming);

	AST_LIST_LOCK(interface_tree);
	AST_LIST_TRAVERSE(interface_tree, monitor, next) {
		if (monitor->id == id) {
			break;
		}
	}

	if (!monitor) {
		AST_LIST_UNLOCK(interface_tree);
		return;
	}

	extension_pvt = monitor->private_data;
	if (!(child_dialstring = ast_calloc(1, sizeof(*child_dialstring)))) {
		AST_LIST_UNLOCK(interface_tree);
		return;
	}
	ast_copy_string(child_dialstring->original_dialstring, dialstring, sizeof(child_dialstring->original_dialstring));
	ast_copy_string(child_dialstring->device_name, device_name, sizeof(child_dialstring->device_name));
	child_dialstring->is_valid = 1;
	AST_LIST_INSERT_TAIL(&extension_pvt->child_dialstrings, child_dialstring, next);
	AST_LIST_UNLOCK(interface_tree);
}

static void cc_extension_monitor_change_is_valid(struct cc_core_instance *core_instance, unsigned int parent_id, const char * const device_name, int is_valid)
{
	struct ast_cc_monitor *monitor_iter;
	struct extension_monitor_pvt *extension_pvt;
	struct extension_child_dialstring *child_dialstring;

	AST_LIST_TRAVERSE(core_instance->monitors, monitor_iter, next) {
		if (monitor_iter->id == parent_id) {
			break;
		}
	}

	if (!monitor_iter) {
		return;
	}
	extension_pvt = monitor_iter->private_data;

	AST_LIST_TRAVERSE(&extension_pvt->child_dialstrings, child_dialstring, next) {
		if (!strcmp(child_dialstring->device_name, device_name)) {
			child_dialstring->is_valid = is_valid;
			break;
		}
	}
}

/*!
 * \internal
 * \brief Allocate and initialize an "extension" interface for CC purposes
 *
 * When app_dial starts, this function is called in order to set up the
 * information about the extension in which this Dial is occurring. Any
 * devices dialed will have this particular cc_monitor as a parent.
 *
 * \param exten Extension from which Dial is occurring
 * \param context Context to which exten belongs
 * \param parent_id What should we set the parent_id of this interface to?
 * \retval NULL Memory allocation failure
 * \retval non-NULL The newly-created cc_monitor for the extension
 */
static struct ast_cc_monitor *cc_extension_monitor_init(const char * const exten, const char * const context, const unsigned int parent_id)
{
	struct ast_str *str = ast_str_alloca(2 * AST_MAX_EXTENSION);
	struct ast_cc_interface *cc_interface;
	struct ast_cc_monitor *monitor;

	ast_str_set(&str, 0, "%s@%s", exten, context);

	if (!(cc_interface = ao2_t_alloc(sizeof(*cc_interface) + ast_str_strlen(str), cc_interface_destroy,
					"Allocating new ast_cc_interface"))) {
		return NULL;
	}

	if (!(monitor = ao2_t_alloc(sizeof(*monitor), cc_monitor_destroy, "Allocating new ast_cc_monitor"))) {
		cc_unref(cc_interface, "failed to allocate the monitor, so unref the interface");
		return NULL;
	}

	if (!(monitor->private_data = extension_monitor_pvt_init())) {
		cc_unref(monitor, "Failed to initialize extension monitor private data. uref monitor");
		cc_unref(cc_interface, "Failed to initialize extension monitor private data. unref cc_interface");
	}

	monitor->id = ast_atomic_fetchadd_int(&dialed_cc_interface_counter, +1);
	monitor->parent_id = parent_id;
	cc_interface->monitor_type = "extension";
	cc_interface->monitor_class = AST_CC_EXTENSION_MONITOR;
	strcpy(cc_interface->device_name, ast_str_buffer(str));
	monitor->interface = cc_interface;
	ast_log_dynamic_level(cc_logger_level, "Created an extension cc interface for '%s' with id %u and parent %u\n", cc_interface->device_name, monitor->id, monitor->parent_id);
	return monitor;
}

/*!
 * \internal
 * \brief allocate dialed_cc_interfaces datastore and initialize fields
 *
 * This function is called when Situation 1 occurs in ast_cc_call_init.
 * See that function for more information on what Situation 1 is.
 *
 * In this particular case, we have to do a lot of memory allocation in order
 * to create the datastore, the data for the datastore, the tree of interfaces
 * that we'll be adding to, and the initial extension interface for this Dial
 * attempt.
 *
 * \param chan The channel onto which the datastore should be added.
 * \retval -1 An error occurred
 * \retval 0 Success
 */
static int cc_interfaces_datastore_init(struct ast_channel *chan) {
	struct dialed_cc_interfaces *interfaces;
	struct ast_cc_monitor *monitor;
	struct ast_datastore *dial_cc_datastore;

	/*XXX This may be a bit controversial. In an attempt to not allocate
	 * extra resources, I make sure that a future request will be within
	 * limits. The problem here is that it is reasonable to think that
	 * even if we're not within the limits at this point, we may be by
	 * the time the requestor will have made his request. This may be
	 * deleted at some point.
	 */
	if (!ast_cc_request_is_within_limits()) {
		return 0;
	}

	if (!(interfaces = ast_calloc(1, sizeof(*interfaces)))) {
		return -1;
	}

	if (!(monitor = cc_extension_monitor_init(S_OR(ast_channel_macroexten(chan), ast_channel_exten(chan)), S_OR(ast_channel_macrocontext(chan), ast_channel_context(chan)), 0))) {
		ast_free(interfaces);
		return -1;
	}

	if (!(dial_cc_datastore = ast_datastore_alloc(&dialed_cc_interfaces_info, NULL))) {
		cc_unref(monitor, "Could not allocate the dialed interfaces datastore. Unreffing monitor");
		ast_free(interfaces);
		return -1;
	}

	if (!(interfaces->interface_tree = ao2_t_alloc(sizeof(*interfaces->interface_tree), cc_interface_tree_destroy,
					"Allocate monitor tree"))) {
		ast_datastore_free(dial_cc_datastore);
		cc_unref(monitor, "Could not allocate monitor tree on dialed interfaces datastore. Unreffing monitor");
		ast_free(interfaces);
		return -1;
	}

	/* Finally, all that allocation is done... */
	AST_LIST_HEAD_INIT(interfaces->interface_tree);
	AST_LIST_INSERT_TAIL(interfaces->interface_tree, monitor, next);
	cc_ref(monitor, "List's reference to extension monitor");
	dial_cc_datastore->data = interfaces;
	dial_cc_datastore->inheritance = DATASTORE_INHERIT_FOREVER;
	interfaces->dial_parent_id = monitor->id;
	interfaces->core_id = monitor->core_id = ast_atomic_fetchadd_int(&core_id_counter, +1);
	interfaces->is_original_caller = 1;
	ast_channel_lock(chan);
	ast_channel_datastore_add(chan, dial_cc_datastore);
	ast_channel_unlock(chan);
	cc_unref(monitor, "Unreffing allocation's reference");
	return 0;
}

/*!
 * \internal
 * \brief  Call a monitor's destructor before the monitor has been allocated
 * \since 1.8
 *
 * \param monitor_type The type of monitor callbacks to use when calling the destructor
 * \param private_data Data allocated by a channel driver that must be freed
 *
 * \details
 * I'll admit, this is a bit evil.
 *
 * When a channel driver determines that it can offer a call completion service to
 * a caller, it is very likely that the channel driver will need to allocate some
 * data so that when the time comes to request CC, the channel driver will have the
 * necessary data at hand.
 *
 * The problem is that there are many places where failures may occur before the monitor
 * has been properly allocated and had its callbacks assigned to it. If one of these
 * failures should occur, then we still need to let the channel driver know that it
 * must destroy the data that it allocated.
 *
 * \return Nothing
 */
static void call_destructor_with_no_monitor(const char * const monitor_type, void *private_data)
{
	const struct ast_cc_monitor_callbacks *monitor_callbacks = find_monitor_callbacks(monitor_type);

	if (!monitor_callbacks) {
		return;
	}

	monitor_callbacks->destructor(private_data);
}

/*!
 * \internal
 * \brief Allocate and intitialize a device cc_monitor
 *
 * For all intents and purposes, this is the same as
 * cc_extension_monitor_init, except that there is only
 * a single parameter used for naming the interface.
 *
 * This function is called when handling AST_CONTROL_CC frames.
 * The device has reported that CC is possible, so we add it
 * to the interface_tree.
 *
 * Note that it is not necessarily erroneous to add the same
 * device to the tree twice. If the same device is called by
 * two different extension during the same call, then
 * that is a legitimate situation.
 *
 * \param device_name The name of the device being added to the tree
 * \param dialstring The dialstring used to dial the device being added
 * \param parent_id The parent of this new tree node.
 * \retval NULL Memory allocation failure
 * \retval non-NULL The new ast_cc_interface created.
 */
static struct ast_cc_monitor *cc_device_monitor_init(const char * const device_name, const char * const dialstring, const struct cc_control_payload *cc_data, int core_id)
{
	struct ast_cc_interface *cc_interface;
	struct ast_cc_monitor *monitor;
	size_t device_name_len = strlen(device_name);
	int parent_id = cc_data->parent_interface_id;

	if (!(cc_interface = ao2_t_alloc(sizeof(*cc_interface) + device_name_len, cc_interface_destroy,
					"Allocating new ast_cc_interface"))) {
		return NULL;
	}

	if (!(cc_interface->config_params = ast_cc_config_params_init())) {
		cc_unref(cc_interface, "Failed to allocate config params, unref interface");
		return NULL;
	}

	if (!(monitor = ao2_t_alloc(sizeof(*monitor), cc_monitor_destroy, "Allocating new ast_cc_monitor"))) {
		cc_unref(cc_interface, "Failed to allocate monitor, unref interface");
		return NULL;
	}

	if (!(monitor->dialstring = ast_strdup(dialstring))) {
		cc_unref(monitor, "Failed to copy dialable name. Unref monitor");
		cc_unref(cc_interface, "Failed to copy dialable name");
		return NULL;
	}

	if (!(monitor->callbacks = find_monitor_callbacks(cc_data->monitor_type))) {
		cc_unref(monitor, "Failed to find monitor callbacks. Unref monitor");
		cc_unref(cc_interface, "Failed to find monitor callbacks");
		return NULL;
	}

	strcpy(cc_interface->device_name, device_name);
	monitor->id = ast_atomic_fetchadd_int(&dialed_cc_interface_counter, +1);
	monitor->parent_id = parent_id;
	monitor->core_id = core_id;
	monitor->service_offered = cc_data->service;
	monitor->private_data = cc_data->private_data;
	cc_interface->monitor_type = cc_data->monitor_type;
	cc_interface->monitor_class = AST_CC_DEVICE_MONITOR;
	monitor->interface = cc_interface;
	monitor->available_timer_id = -1;
	ast_cc_copy_config_params(cc_interface->config_params, &cc_data->config_params);
	ast_log_dynamic_level(cc_logger_level, "Core %d: Created a device cc interface for '%s' with id %u and parent %u\n",
			monitor->core_id, cc_interface->device_name, monitor->id, monitor->parent_id);
	return monitor;
}

/*!
 * \details
 * Unless we are ignoring CC for some reason, we will always
 * call this function when we read an AST_CONTROL_CC frame
 * from an outbound channel.
 *
 * This function will call cc_device_monitor_init to
 * create the new cc_monitor for the device from which
 * we read the frame. In addition, the new device will be added
 * to the monitor tree on the dialed_cc_interfaces datastore
 * on the inbound channel.
 *
 * If this is the first AST_CONTROL_CC frame that we have handled
 * for this call, then we will also initialize the CC core for
 * this call.
 */
void ast_handle_cc_control_frame(struct ast_channel *inbound, struct ast_channel *outbound, void *frame_data)
{
	char *device_name;
	char *dialstring;
	struct ast_cc_monitor *monitor;
	struct ast_datastore *cc_datastore;
	struct dialed_cc_interfaces *cc_interfaces;
	struct cc_control_payload *cc_data = frame_data;
	struct cc_core_instance *core_instance;

	device_name = cc_data->device_name;
	dialstring = cc_data->dialstring;

	ast_channel_lock(inbound);
	if (!(cc_datastore = ast_channel_datastore_find(inbound, &dialed_cc_interfaces_info, NULL))) {
		ast_log(LOG_WARNING, "Unable to retrieve CC datastore while processing CC frame from '%s'. CC services will be unavailable.\n", device_name);
		ast_channel_unlock(inbound);
		call_destructor_with_no_monitor(cc_data->monitor_type, cc_data->private_data);
		return;
	}

	cc_interfaces = cc_datastore->data;

	if (cc_interfaces->ignore) {
		ast_channel_unlock(inbound);
		call_destructor_with_no_monitor(cc_data->monitor_type, cc_data->private_data);
		return;
	}

	if (!cc_interfaces->is_original_caller) {
		/* If the is_original_caller is not set on the *inbound* channel, then
		 * it must be a local channel. As such, we do not want to create a core instance
		 * or an agent for the local channel. Instead, we want to pass this along to the
		 * other side of the local channel so that the original caller can benefit.
		 */
		ast_channel_unlock(inbound);
		ast_indicate_data(inbound, AST_CONTROL_CC, cc_data, sizeof(*cc_data));
		return;
	}

	core_instance = find_cc_core_instance(cc_interfaces->core_id);
	if (!core_instance) {
		core_instance = cc_core_init_instance(inbound, cc_interfaces->interface_tree,
			cc_interfaces->core_id, cc_data);
		if (!core_instance) {
			cc_interfaces->ignore = 1;
			ast_channel_unlock(inbound);
			call_destructor_with_no_monitor(cc_data->monitor_type, cc_data->private_data);
			return;
		}
	}

	ast_channel_unlock(inbound);

	/* Yeah this kind of sucks, but luckily most people
	 * aren't dialing thousands of interfaces on every call
	 *
	 * This traversal helps us to not create duplicate monitors in
	 * case a device queues multiple CC control frames.
	 */
	AST_LIST_LOCK(cc_interfaces->interface_tree);
	AST_LIST_TRAVERSE(cc_interfaces->interface_tree, monitor, next) {
		if (!strcmp(monitor->interface->device_name, device_name)) {
			ast_log_dynamic_level(cc_logger_level, "Core %d: Device %s sent us multiple CC control frames. Ignoring those beyond the first.\n",
					core_instance->core_id, device_name);
			AST_LIST_UNLOCK(cc_interfaces->interface_tree);
			cc_unref(core_instance, "Returning early from ast_handle_cc_control_frame. Unref core_instance");
			call_destructor_with_no_monitor(cc_data->monitor_type, cc_data->private_data);
			return;
		}
	}
	AST_LIST_UNLOCK(cc_interfaces->interface_tree);

	if (!(monitor = cc_device_monitor_init(device_name, dialstring, cc_data, core_instance->core_id))) {
		ast_log(LOG_WARNING, "Unable to create CC device interface for '%s'. CC services will be unavailable on this interface.\n", device_name);
		cc_unref(core_instance, "Returning early from ast_handle_cc_control_frame. Unref core_instance");
		call_destructor_with_no_monitor(cc_data->monitor_type, cc_data->private_data);
		return;
	}

	AST_LIST_LOCK(cc_interfaces->interface_tree);
	cc_ref(monitor, "monitor tree's reference to the monitor");
	AST_LIST_INSERT_TAIL(cc_interfaces->interface_tree, monitor, next);
	AST_LIST_UNLOCK(cc_interfaces->interface_tree);

	cc_extension_monitor_change_is_valid(core_instance, monitor->parent_id, monitor->interface->device_name, 0);

	cc_publish_available(cc_interfaces->core_id, device_name, cc_service_to_string(cc_data->service));

	cc_unref(core_instance, "Done with core_instance after handling CC control frame");
	cc_unref(monitor, "Unref reference from allocating monitor");
}

int ast_cc_call_init(struct ast_channel *chan, int *ignore_cc)
{
	/* There are three situations to deal with here:
	 *
	 * 1. The channel does not have a dialed_cc_interfaces datastore on
	 * it. This means that this is the first time that Dial has
	 * been called. We need to create/initialize the datastore.
	 *
	 * 2. The channel does have a cc_interface datastore on it and
	 * the "ignore" indicator is 0. This means that a Local channel
	 * was called by a "parent" dial. We can check the datastore's
	 * parent field to see who the root of this particular dial tree
	 * is.
	 *
	 * 3. The channel does have a cc_interface datastore on it and
	 * the "ignore" indicator is 1. This means that a second Dial call
	 * is being made from an extension. In this case, we do not
	 * want to make any additions/modifications to the datastore. We
	 * will instead set a flag to indicate that CCSS is completely
	 * disabled for this Dial attempt.
	 */

	struct ast_datastore *cc_interfaces_datastore;
	struct dialed_cc_interfaces *interfaces;
	struct ast_cc_monitor *monitor;
	struct ast_cc_config_params *cc_params;

	ast_channel_lock(chan);

	cc_params = ast_channel_get_cc_config_params(chan);
	if (!cc_params) {
		ast_channel_unlock(chan);
		return -1;
	}
	if (ast_get_cc_agent_policy(cc_params) == AST_CC_AGENT_NEVER) {
		/* We can't offer CC to this caller anyway, so don't bother with CC on this call
		 */
		*ignore_cc = 1;
		ast_channel_unlock(chan);
		ast_log_dynamic_level(cc_logger_level, "Agent policy for %s is 'never'. CC not possible\n", ast_channel_name(chan));
		return 0;
	}

	if (!(cc_interfaces_datastore = ast_channel_datastore_find(chan, &dialed_cc_interfaces_info, NULL))) {
		/* Situation 1 has occurred */
		ast_channel_unlock(chan);
		return cc_interfaces_datastore_init(chan);
	}
	interfaces = cc_interfaces_datastore->data;
	ast_channel_unlock(chan);

	if (interfaces->ignore) {
		/* Situation 3 has occurred */
		*ignore_cc = 1;
		ast_log_dynamic_level(cc_logger_level, "Datastore is present with ignore flag set. Ignoring CC offers on this call\n");
		return 0;
	}

	/* Situation 2 has occurred */
	if (!(monitor = cc_extension_monitor_init(S_OR(ast_channel_macroexten(chan), ast_channel_exten(chan)),
			S_OR(ast_channel_macrocontext(chan), ast_channel_context(chan)), interfaces->dial_parent_id))) {
		return -1;
	}
	monitor->core_id = interfaces->core_id;
	AST_LIST_LOCK(interfaces->interface_tree);
	cc_ref(monitor, "monitor tree's reference to the monitor");
	AST_LIST_INSERT_TAIL(interfaces->interface_tree, monitor, next);
	AST_LIST_UNLOCK(interfaces->interface_tree);
	interfaces->dial_parent_id = monitor->id;
	cc_unref(monitor, "Unref monitor's allocation reference");
	return 0;
}

int ast_cc_request_is_within_limits(void)
{
	return cc_request_count < global_cc_max_requests;
}

int ast_cc_get_current_core_id(struct ast_channel *chan)
{
	struct ast_datastore *datastore;
	struct dialed_cc_interfaces *cc_interfaces;
	int core_id_return;

	ast_channel_lock(chan);
	if (!(datastore = ast_channel_datastore_find(chan, &dialed_cc_interfaces_info, NULL))) {
		ast_channel_unlock(chan);
		return -1;
	}

	cc_interfaces = datastore->data;
	core_id_return = cc_interfaces->ignore ? -1 : cc_interfaces->core_id;
	ast_channel_unlock(chan);
	return core_id_return;

}

static long count_agents(const char * const caller, const int core_id_exception)
{
	struct count_agents_cb_data data = {.core_id_exception = core_id_exception,};

	ao2_t_callback_data(cc_core_instances, OBJ_NODATA, count_agents_cb, (char *)caller, &data, "Counting agents");
	ast_log_dynamic_level(cc_logger_level, "Counted %d agents\n", data.count);
	return data.count;
}

static void kill_duplicate_offers(char *caller)
{
	unsigned long match_flags = MATCH_NO_REQUEST;
	struct ao2_iterator *dups_iter;

	/*
	 * Must remove the ref that was in cc_core_instances outside of
	 * the container lock to prevent deadlock.
	 */
	dups_iter = ao2_t_callback_data(cc_core_instances, OBJ_MULTIPLE | OBJ_UNLINK,
		match_agent, caller, &match_flags, "Killing duplicate offers");
	if (dups_iter) {
		/* Now actually unref any duplicate offers by simply destroying the iterator. */
		ao2_iterator_destroy(dups_iter);
	}
}

static void check_callback_sanity(const struct ast_cc_agent_callbacks *callbacks)
{
	ast_assert(callbacks->init != NULL);
	ast_assert(callbacks->start_offer_timer != NULL);
	ast_assert(callbacks->stop_offer_timer != NULL);
	ast_assert(callbacks->respond != NULL);
	ast_assert(callbacks->status_request != NULL);
	ast_assert(callbacks->start_monitoring != NULL);
	ast_assert(callbacks->callee_available != NULL);
	ast_assert(callbacks->destructor != NULL);
}

static void agent_destroy(void *data)
{
	struct ast_cc_agent *agent = data;

	if (agent->callbacks) {
		agent->callbacks->destructor(agent);
	}
	ast_cc_config_params_destroy(agent->cc_params);
}

static struct ast_cc_agent *cc_agent_init(struct ast_channel *caller_chan,
		const char * const caller_name, const int core_id,
		struct cc_monitor_tree *interface_tree)
{
	struct ast_cc_agent *agent;
	struct ast_cc_config_params *cc_params;

	if (!(agent = ao2_t_alloc(sizeof(*agent) + strlen(caller_name), agent_destroy,
					"Allocating new ast_cc_agent"))) {
		return NULL;
	}

	agent->core_id = core_id;
	strcpy(agent->device_name, caller_name);

	cc_params = ast_channel_get_cc_config_params(caller_chan);
	if (!cc_params) {
		cc_unref(agent, "Could not get channel config params.");
		return NULL;
	}
	if (!(agent->cc_params = ast_cc_config_params_init())) {
		cc_unref(agent, "Could not init agent config params.");
		return NULL;
	}
	ast_cc_copy_config_params(agent->cc_params, cc_params);

	if (!(agent->callbacks = find_agent_callbacks(caller_chan))) {
		cc_unref(agent, "Could not find agent callbacks.");
		return NULL;
	}
	check_callback_sanity(agent->callbacks);

	if (agent->callbacks->init(agent, caller_chan)) {
		cc_unref(agent, "Agent init callback failed.");
		return NULL;
	}
	ast_log_dynamic_level(cc_logger_level, "Core %u: Created an agent for caller %s\n",
			agent->core_id, agent->device_name);
	return agent;
}

/* Generic agent callbacks */
static int cc_generic_agent_init(struct ast_cc_agent *agent, struct ast_channel *chan);
static int cc_generic_agent_start_offer_timer(struct ast_cc_agent *agent);
static int cc_generic_agent_stop_offer_timer(struct ast_cc_agent *agent);
static void cc_generic_agent_respond(struct ast_cc_agent *agent, enum ast_cc_agent_response_reason reason);
static int cc_generic_agent_status_request(struct ast_cc_agent *agent);
static int cc_generic_agent_stop_ringing(struct ast_cc_agent *agent);
static int cc_generic_agent_start_monitoring(struct ast_cc_agent *agent);
static int cc_generic_agent_recall(struct ast_cc_agent *agent);
static void cc_generic_agent_destructor(struct ast_cc_agent *agent);

static struct ast_cc_agent_callbacks generic_agent_callbacks = {
	.type = "generic",
	.init = cc_generic_agent_init,
	.start_offer_timer = cc_generic_agent_start_offer_timer,
	.stop_offer_timer = cc_generic_agent_stop_offer_timer,
	.respond = cc_generic_agent_respond,
	.status_request = cc_generic_agent_status_request,
	.stop_ringing = cc_generic_agent_stop_ringing,
	.start_monitoring = cc_generic_agent_start_monitoring,
	.callee_available = cc_generic_agent_recall,
	.destructor = cc_generic_agent_destructor,
};

struct cc_generic_agent_pvt {
	/*!
	 * Subscription to device state
	 *
	 * Used in the CC_CALLER_BUSY state. The
	 * generic agent will subscribe to the
	 * device state of the caller in order to
	 * determine when we may move on
	 */
	struct stasis_subscription *sub;
	/*!
	 * Scheduler id of offer timer.
	 */
	int offer_timer_id;
	/*!
	 * Caller ID number
	 *
	 * When we re-call the caller, we need
	 * to provide this information to
	 * ast_request_and_dial so that the
	 * information will be present in the
	 * call to the callee
	 */
	char cid_num[AST_CHANNEL_NAME];
	/*!
	 * Caller ID name
	 *
	 * See the description of cid_num.
	 * The same applies here, except this
	 * is the caller's name.
	 */
	char cid_name[AST_CHANNEL_NAME];
	/*!
	 * Extension dialed
	 *
	 * The original extension dialed. This is used
	 * so that when performing a recall, we can
	 * call the proper extension.
	 */
	char exten[AST_CHANNEL_NAME];
	/*!
	 * Context dialed
	 *
	 * The original context dialed. This is used
	 * so that when performaing a recall, we can
	 * call into the proper context
	 */
	char context[AST_CHANNEL_NAME];
};

static int cc_generic_agent_init(struct ast_cc_agent *agent, struct ast_channel *chan)
{
	struct cc_generic_agent_pvt *generic_pvt = ast_calloc(1, sizeof(*generic_pvt));

	if (!generic_pvt) {
		return -1;
	}

	generic_pvt->offer_timer_id = -1;
	if (ast_channel_caller(chan)->id.number.valid && ast_channel_caller(chan)->id.number.str) {
		ast_copy_string(generic_pvt->cid_num, ast_channel_caller(chan)->id.number.str, sizeof(generic_pvt->cid_num));
	}
	if (ast_channel_caller(chan)->id.name.valid && ast_channel_caller(chan)->id.name.str) {
		ast_copy_string(generic_pvt->cid_name, ast_channel_caller(chan)->id.name.str, sizeof(generic_pvt->cid_name));
	}
	ast_copy_string(generic_pvt->exten, S_OR(ast_channel_macroexten(chan), ast_channel_exten(chan)), sizeof(generic_pvt->exten));
	ast_copy_string(generic_pvt->context, S_OR(ast_channel_macrocontext(chan), ast_channel_context(chan)), sizeof(generic_pvt->context));
	agent->private_data = generic_pvt;
	ast_set_flag(agent, AST_CC_AGENT_SKIP_OFFER);
	return 0;
}

static int offer_timer_expire(const void *data)
{
	struct ast_cc_agent *agent = (struct ast_cc_agent *) data;
	struct cc_generic_agent_pvt *agent_pvt = agent->private_data;
	ast_log_dynamic_level(cc_logger_level, "Core %u: Queuing change request because offer timer has expired.\n",
			agent->core_id);
	agent_pvt->offer_timer_id = -1;
	ast_cc_failed(agent->core_id, "Generic agent %s offer timer expired", agent->device_name);
	cc_unref(agent, "Remove scheduler's reference to the agent");
	return 0;
}

static int cc_generic_agent_start_offer_timer(struct ast_cc_agent *agent)
{
	int when;
	int sched_id;
	struct cc_generic_agent_pvt *generic_pvt = agent->private_data;

	ast_assert(cc_sched_context != NULL);
	ast_assert(agent->cc_params != NULL);

	when = ast_get_cc_offer_timer(agent->cc_params) * 1000;
	ast_log_dynamic_level(cc_logger_level, "Core %u: About to schedule offer timer expiration for %d ms\n",
			agent->core_id, when);
	if ((sched_id = ast_sched_add(cc_sched_context, when, offer_timer_expire, cc_ref(agent, "Give scheduler an agent ref"))) == -1) {
		return -1;
	}
	generic_pvt->offer_timer_id = sched_id;
	return 0;
}

static int cc_generic_agent_stop_offer_timer(struct ast_cc_agent *agent)
{
	struct cc_generic_agent_pvt *generic_pvt = agent->private_data;

	if (generic_pvt->offer_timer_id != -1) {
		if (!ast_sched_del(cc_sched_context, generic_pvt->offer_timer_id)) {
			cc_unref(agent, "Remove scheduler's reference to the agent");
		}
		generic_pvt->offer_timer_id = -1;
	}
	return 0;
}

static void cc_generic_agent_respond(struct ast_cc_agent *agent, enum ast_cc_agent_response_reason reason)
{
	/* The generic agent doesn't have to do anything special to
	 * acknowledge a CC request. Just return.
	 */
	return;
}

static int cc_generic_agent_status_request(struct ast_cc_agent *agent)
{
	ast_cc_agent_status_response(agent->core_id, ast_device_state(agent->device_name));
	return 0;
}

static int cc_generic_agent_stop_ringing(struct ast_cc_agent *agent)
{
	struct ast_channel *recall_chan = ast_channel_get_by_name_prefix(agent->device_name, strlen(agent->device_name));

	if (!recall_chan) {
		return 0;
	}

	ast_softhangup(recall_chan, AST_SOFTHANGUP_EXPLICIT);
	return 0;
}

static void generic_agent_devstate_cb(void *userdata, struct stasis_subscription *sub, struct stasis_message *msg)
{
	struct ast_cc_agent *agent = userdata;
	enum ast_device_state new_state;
	struct ast_device_state_message *dev_state;
	struct cc_generic_agent_pvt *generic_pvt = agent->private_data;

	if (stasis_subscription_final_message(sub, msg)) {
		cc_unref(agent, "Done holding ref for subscription");
		return;
	} else if (ast_device_state_message_type() != stasis_message_type(msg)) {
		return;
	}

	dev_state = stasis_message_data(msg);
	if (dev_state->eid) {
		/* ignore non-aggregate states */
		return;
	}

	new_state = dev_state->state;
	if (!cc_generic_is_device_available(new_state)) {
		/* Not interested in this new state of the device.  It is still busy. */
		return;
	}

	generic_pvt->sub = stasis_unsubscribe(sub);
	ast_cc_agent_caller_available(agent->core_id, "%s is no longer busy", agent->device_name);
}

static int cc_generic_agent_start_monitoring(struct ast_cc_agent *agent)
{
	struct cc_generic_agent_pvt *generic_pvt = agent->private_data;
	struct ast_str *str = ast_str_alloca(128);
	struct stasis_topic *device_specific_topic;

	ast_assert(generic_pvt->sub == NULL);
	ast_str_set(&str, 0, "Agent monitoring %s device state since it is busy\n",
		agent->device_name);

	device_specific_topic = ast_device_state_topic(agent->device_name);
	if (!device_specific_topic) {
		return -1;
	}

	if (!(generic_pvt->sub = stasis_subscribe(device_specific_topic, generic_agent_devstate_cb, agent))) {
		return -1;
	}
	stasis_subscription_accept_message_type(generic_pvt->sub, ast_device_state_message_type());
	stasis_subscription_accept_message_type(generic_pvt->sub, stasis_subscription_change_type());
	stasis_subscription_set_filter(generic_pvt->sub, STASIS_SUBSCRIPTION_FILTER_SELECTIVE);
	cc_ref(agent, "Ref agent for subscription");
	return 0;
}

static void *generic_recall(void *data)
{
	struct ast_cc_agent *agent = data;
	struct cc_generic_agent_pvt *generic_pvt = agent->private_data;
	const char *interface = S_OR(ast_get_cc_agent_dialstring(agent->cc_params), ast_strdupa(agent->device_name));
	const char *tech;
	char *target;
	int reason;
	struct ast_channel *chan;
	const char *callback_macro = ast_get_cc_callback_macro(agent->cc_params);
	const char *callback_sub = ast_get_cc_callback_sub(agent->cc_params);
	unsigned int recall_timer = ast_get_cc_recall_timer(agent->cc_params) * 1000;
	struct ast_format_cap *tmp_cap = ast_format_cap_alloc(AST_FORMAT_CAP_FLAG_DEFAULT);

	if (!tmp_cap) {
		return NULL;
	}

	tech = interface;
	if ((target = strchr(interface, '/'))) {
		*target++ = '\0';
	}

	ast_format_cap_append(tmp_cap, ast_format_slin, 0);
	if (!(chan = ast_request_and_dial(tech, tmp_cap, NULL, NULL, target, recall_timer, &reason, generic_pvt->cid_num, generic_pvt->cid_name))) {
		/* Hmm, no channel. Sucks for you, bud.
		 */
		ast_log_dynamic_level(cc_logger_level, "Core %u: Failed to call back %s for reason %d\n",
				agent->core_id, agent->device_name, reason);
		ast_cc_failed(agent->core_id, "Failed to call back device %s/%s", tech, target);
		ao2_ref(tmp_cap, -1);
		return NULL;
	}
	ao2_ref(tmp_cap, -1);

	/* We have a channel. It's time now to set up the datastore of recalled CC interfaces.
	 * This will be a common task for all recall functions. If it were possible, I'd have
	 * the core do it automatically, but alas I cannot. Instead, I will provide a public
	 * function to do so.
	 */
	ast_setup_cc_recall_datastore(chan, agent->core_id);
	ast_cc_agent_set_interfaces_chanvar(chan);

	ast_channel_exten_set(chan, generic_pvt->exten);
	ast_channel_context_set(chan, generic_pvt->context);
	ast_channel_priority_set(chan, 1);

	pbx_builtin_setvar_helper(chan, "CC_EXTEN", generic_pvt->exten);
	pbx_builtin_setvar_helper(chan, "CC_CONTEXT", generic_pvt->context);

	if (!ast_strlen_zero(callback_macro)) {
		ast_log_dynamic_level(cc_logger_level, "Core %u: There's a callback macro configured for agent %s\n",
				agent->core_id, agent->device_name);
		if (ast_app_exec_macro(NULL, chan, callback_macro)) {
			ast_cc_failed(agent->core_id, "Callback macro to %s failed. Maybe a hangup?", agent->device_name);
			ast_hangup(chan);
			return NULL;
		}
	}

	if (!ast_strlen_zero(callback_sub)) {
		ast_log_dynamic_level(cc_logger_level, "Core %u: There's a callback subroutine configured for agent %s\n",
				agent->core_id, agent->device_name);
		if (ast_app_exec_sub(NULL, chan, callback_sub, 0)) {
			ast_cc_failed(agent->core_id, "Callback subroutine to %s failed. Maybe a hangup?", agent->device_name);
			ast_hangup(chan);
			return NULL;
		}
	}
	if (ast_pbx_start(chan)) {
		ast_cc_failed(agent->core_id, "PBX failed to start for %s.", agent->device_name);
		ast_hangup(chan);
		return NULL;
	}
	ast_cc_agent_recalling(agent->core_id, "Generic agent %s is recalling",
		agent->device_name);
	return NULL;
}

static int cc_generic_agent_recall(struct ast_cc_agent *agent)
{
	pthread_t clotho;
	enum ast_device_state current_state = ast_device_state(agent->device_name);

	if (!cc_generic_is_device_available(current_state)) {
		/* We can't try to contact the device right now because he's not available
		 * Let the core know he's busy.
		 */
		ast_cc_agent_caller_busy(agent->core_id, "Generic agent caller %s is busy", agent->device_name);
		return 0;
	}
	ast_pthread_create_detached_background(&clotho, NULL, generic_recall, agent);
	return 0;
}

static void cc_generic_agent_destructor(struct ast_cc_agent *agent)
{
	struct cc_generic_agent_pvt *agent_pvt = agent->private_data;

	if (!agent_pvt) {
		/* The agent constructor probably failed. */
		return;
	}

	cc_generic_agent_stop_offer_timer(agent);
	if (agent_pvt->sub) {
		agent_pvt->sub = stasis_unsubscribe(agent_pvt->sub);
	}

	ast_free(agent_pvt);
}

static void cc_core_instance_destructor(void *data)
{
	struct cc_core_instance *core_instance = data;
	ast_log_dynamic_level(cc_logger_level, "Core %d: Destroying core instance\n", core_instance->core_id);
	if (core_instance->agent) {
		cc_unref(core_instance->agent, "Core instance is done with the agent now");
	}
	if (core_instance->monitors) {
		core_instance->monitors = cc_unref(core_instance->monitors, "Core instance is done with interface list");
	}
}

static struct cc_core_instance *cc_core_init_instance(struct ast_channel *caller_chan,
		struct cc_monitor_tree *called_tree, const int core_id, struct cc_control_payload *cc_data)
{
	char caller[AST_CHANNEL_NAME];
	struct cc_core_instance *core_instance;
	struct ast_cc_config_params *cc_params;
	long agent_count;
	int recall_core_id;

	ast_channel_get_device_name(caller_chan, caller, sizeof(caller));
	cc_params = ast_channel_get_cc_config_params(caller_chan);
	if (!cc_params) {
		ast_log_dynamic_level(cc_logger_level, "Could not get CC parameters for %s\n",
			caller);
		return NULL;
	}
	/* First, we need to kill off other pending CC offers from caller. If the caller is going
	 * to request a CC service, it may only be for the latest call he made.
	 */
	if (ast_get_cc_agent_policy(cc_params) == AST_CC_AGENT_GENERIC) {
		kill_duplicate_offers(caller);
	}

	ast_cc_is_recall(caller_chan, &recall_core_id, NULL);
	agent_count = count_agents(caller, recall_core_id);
	if (agent_count >= ast_get_cc_max_agents(cc_params)) {
		ast_log_dynamic_level(cc_logger_level, "Caller %s already has the maximum number of agents configured\n", caller);
		return NULL;
	}

	/* Generic agents can only have a single outstanding CC request per caller. */
	if (agent_count > 0 && ast_get_cc_agent_policy(cc_params) == AST_CC_AGENT_GENERIC) {
		ast_log_dynamic_level(cc_logger_level, "Generic agents can only have a single outstanding request\n");
		return NULL;
	}

	/* Next, we need to create the core instance for this call */
	if (!(core_instance = ao2_t_alloc(sizeof(*core_instance), cc_core_instance_destructor, "Creating core instance for CC"))) {
		return NULL;
	}

	core_instance->core_id = core_id;
	if (!(core_instance->agent = cc_agent_init(caller_chan, caller, core_instance->core_id, called_tree))) {
		cc_unref(core_instance, "Couldn't allocate agent, unref core_instance");
		return NULL;
	}

	core_instance->monitors = cc_ref(called_tree, "Core instance getting ref to monitor tree");

	ao2_t_link(cc_core_instances, core_instance, "Link core instance into container");

	return core_instance;
}

struct cc_state_change_args {
	struct cc_core_instance *core_instance;/*!< Holds reference to core instance. */
	enum cc_state state;
	int core_id;
	char debug[1];
};

static int is_state_change_valid(enum cc_state current_state, const enum cc_state new_state, struct ast_cc_agent *agent)
{
	int is_valid = 0;
	switch (new_state) {
	case CC_AVAILABLE:
		ast_log_dynamic_level(cc_logger_level, "Core %u: Asked to change to state %u? That should never happen.\n",
				agent->core_id, new_state);
		break;
	case CC_CALLER_OFFERED:
		if (current_state == CC_AVAILABLE) {
			is_valid = 1;
		}
		break;
	case CC_CALLER_REQUESTED:
		if (current_state == CC_CALLER_OFFERED ||
				(current_state == CC_AVAILABLE && ast_test_flag(agent, AST_CC_AGENT_SKIP_OFFER))) {
			is_valid = 1;
		}
		break;
	case CC_ACTIVE:
		if (current_state == CC_CALLER_REQUESTED || current_state == CC_CALLER_BUSY) {
			is_valid = 1;
		}
		break;
	case CC_CALLEE_READY:
		if (current_state == CC_ACTIVE) {
			is_valid = 1;
		}
		break;
	case CC_CALLER_BUSY:
		if (current_state == CC_CALLEE_READY) {
			is_valid = 1;
		}
		break;
	case CC_RECALLING:
		if (current_state == CC_CALLEE_READY) {
			is_valid = 1;
		}
		break;
	case CC_COMPLETE:
		if (current_state == CC_RECALLING) {
			is_valid = 1;
		}
		break;
	case CC_FAILED:
		is_valid = 1;
		break;
	default:
		ast_log_dynamic_level(cc_logger_level, "Core %u: Asked to change to unknown state %u\n",
				agent->core_id, new_state);
		break;
	}

	return is_valid;
}

static int cc_available(struct cc_core_instance *core_instance, struct cc_state_change_args *args, enum cc_state previous_state)
{
	/* This should never happen... */
	ast_log(LOG_WARNING, "Someone requested to change to CC_AVAILABLE? Ignoring.\n");
	return -1;
}

static int cc_caller_offered(struct cc_core_instance *core_instance, struct cc_state_change_args *args, enum cc_state previous_state)
{
	if (core_instance->agent->callbacks->start_offer_timer(core_instance->agent)) {
		ast_cc_failed(core_instance->core_id, "Failed to start the offer timer for %s\n",
				core_instance->agent->device_name);
		return -1;
	}
	cc_publish_offertimerstart(core_instance->core_id, core_instance->agent->device_name, core_instance->agent->cc_params->cc_offer_timer);
	ast_log_dynamic_level(cc_logger_level, "Core %d: Started the offer timer for the agent %s!\n",
			core_instance->core_id, core_instance->agent->device_name);
	return 0;
}

/*!
 * \brief check if the core instance has any device monitors
 *
 * In any case where we end up removing a device monitor from the
 * list of device monitors, it is important to see what the state
 * of the list is afterwards. If we find that we only have extension
 * monitors left, then no devices are actually being monitored.
 * In such a case, we need to declare that CC has failed for this
 * call. This function helps those cases to determine if they should
 * declare failure.
 *
 * \param core_instance The core instance we are checking for the existence
 * of device monitors
 * \retval 0 No device monitors exist on this core_instance
 * \retval 1 There is still at least 1 device monitor remaining
 */
static int has_device_monitors(struct cc_core_instance *core_instance)
{
	struct ast_cc_monitor *iter;
	int res = 0;

	AST_LIST_TRAVERSE(core_instance->monitors, iter, next) {
		if (iter->interface->monitor_class == AST_CC_DEVICE_MONITOR) {
			res = 1;
			break;
		}
	}

	return res;
}

static void request_cc(struct cc_core_instance *core_instance)
{
	struct ast_cc_monitor *monitor_iter;
	AST_LIST_LOCK(core_instance->monitors);
	AST_LIST_TRAVERSE_SAFE_BEGIN(core_instance->monitors, monitor_iter, next) {
		if (monitor_iter->interface->monitor_class == AST_CC_DEVICE_MONITOR) {
			if (monitor_iter->callbacks->request_cc(monitor_iter, &monitor_iter->available_timer_id)) {
				AST_LIST_REMOVE_CURRENT(next);
				cc_extension_monitor_change_is_valid(core_instance, monitor_iter->parent_id,
						monitor_iter->interface->device_name, 1);
				cc_unref(monitor_iter, "request_cc failed. Unref list's reference to monitor");
			} else {
				cc_publish_requested(core_instance->core_id, core_instance->agent->device_name, monitor_iter->interface->device_name);
			}
		}
	}
	AST_LIST_TRAVERSE_SAFE_END;

	if (!has_device_monitors(core_instance)) {
		ast_cc_failed(core_instance->core_id, "All device monitors failed to request CC");
	}
	AST_LIST_UNLOCK(core_instance->monitors);
}

static int cc_caller_requested(struct cc_core_instance *core_instance, struct cc_state_change_args *args, enum cc_state previous_state)
{
	if (!ast_cc_request_is_within_limits()) {
		ast_log(LOG_WARNING, "Cannot request CC since there is no more room for requests\n");
		core_instance->agent->callbacks->respond(core_instance->agent,
			AST_CC_AGENT_RESPONSE_FAILURE_TOO_MANY);
		ast_cc_failed(core_instance->core_id, "Too many requests in the system");
		return -1;
	}
	core_instance->agent->callbacks->stop_offer_timer(core_instance->agent);
	request_cc(core_instance);
	return 0;
}

static void unsuspend(struct cc_core_instance *core_instance)
{
	struct ast_cc_monitor *monitor_iter;
	AST_LIST_LOCK(core_instance->monitors);
	AST_LIST_TRAVERSE_SAFE_BEGIN(core_instance->monitors, monitor_iter, next) {
		if (monitor_iter->interface->monitor_class == AST_CC_DEVICE_MONITOR) {
			if (monitor_iter->callbacks->unsuspend(monitor_iter)) {
				AST_LIST_REMOVE_CURRENT(next);
				cc_extension_monitor_change_is_valid(core_instance, monitor_iter->parent_id,
						monitor_iter->interface->device_name, 1);
				cc_unref(monitor_iter, "unsuspend failed. Unref list's reference to monitor");
			}
		}
	}
	AST_LIST_TRAVERSE_SAFE_END;

	if (!has_device_monitors(core_instance)) {
		ast_cc_failed(core_instance->core_id, "All device monitors failed to unsuspend CC");
	}
	AST_LIST_UNLOCK(core_instance->monitors);
}

static int cc_active(struct cc_core_instance *core_instance, struct cc_state_change_args *args, enum cc_state previous_state)
{
	/* Either
	 * 1. Callee accepted CC request, call agent's ack callback.
	 * 2. Caller became available, call agent's stop_monitoring callback and
	 *    call monitor's unsuspend callback.
	 */
	if (previous_state == CC_CALLER_REQUESTED) {
		core_instance->agent->callbacks->respond(core_instance->agent,
			AST_CC_AGENT_RESPONSE_SUCCESS);
		cc_publish_requestacknowledged(core_instance->core_id, core_instance->agent->device_name);
	} else if (previous_state == CC_CALLER_BUSY) {
		cc_publish_callerstopmonitoring(core_instance->core_id, core_instance->agent->device_name);
		unsuspend(core_instance);
	}
	/* Not possible for previous_state to be anything else due to the is_state_change_valid check at the beginning */
	return 0;
}

static int cc_callee_ready(struct cc_core_instance *core_instance, struct cc_state_change_args *args, enum cc_state previous_state)
{
	core_instance->agent->callbacks->callee_available(core_instance->agent);
	return 0;
}

static void suspend(struct cc_core_instance *core_instance)
{
	struct ast_cc_monitor *monitor_iter;
	AST_LIST_LOCK(core_instance->monitors);
	AST_LIST_TRAVERSE_SAFE_BEGIN(core_instance->monitors, monitor_iter, next) {
		if (monitor_iter->interface->monitor_class == AST_CC_DEVICE_MONITOR) {
			if (monitor_iter->callbacks->suspend(monitor_iter)) {
				AST_LIST_REMOVE_CURRENT(next);
				cc_extension_monitor_change_is_valid(core_instance, monitor_iter->parent_id,
						monitor_iter->interface->device_name, 1);
				cc_unref(monitor_iter, "suspend failed. Unref list's reference to monitor");
			}
		}
	}
	AST_LIST_TRAVERSE_SAFE_END;

	if (!has_device_monitors(core_instance)) {
		ast_cc_failed(core_instance->core_id, "All device monitors failed to suspend CC");
	}
	AST_LIST_UNLOCK(core_instance->monitors);
}

static int cc_caller_busy(struct cc_core_instance *core_instance, struct cc_state_change_args *args, enum cc_state previous_state)
{
	/* Callee was available, but caller was busy, call agent's begin_monitoring callback
	 * and call monitor's suspend callback.
	 */
	suspend(core_instance);
	core_instance->agent->callbacks->start_monitoring(core_instance->agent);
	cc_publish_callerstartmonitoring(core_instance->core_id, core_instance->agent->device_name);
	return 0;
}

static void cancel_available_timer(struct cc_core_instance *core_instance)
{
	struct ast_cc_monitor *monitor_iter;
	AST_LIST_LOCK(core_instance->monitors);
	AST_LIST_TRAVERSE_SAFE_BEGIN(core_instance->monitors, monitor_iter, next) {
		if (monitor_iter->interface->monitor_class == AST_CC_DEVICE_MONITOR) {
			if (monitor_iter->callbacks->cancel_available_timer(monitor_iter, &monitor_iter->available_timer_id)) {
				AST_LIST_REMOVE_CURRENT(next);
				cc_extension_monitor_change_is_valid(core_instance, monitor_iter->parent_id,
						monitor_iter->interface->device_name, 1);
				cc_unref(monitor_iter, "cancel_available_timer failed. Unref list's reference to monitor");
			}
		}
	}
	AST_LIST_TRAVERSE_SAFE_END;

	if (!has_device_monitors(core_instance)) {
		ast_cc_failed(core_instance->core_id, "All device monitors failed to cancel their available timers");
	}
	AST_LIST_UNLOCK(core_instance->monitors);
}

static int cc_recalling(struct cc_core_instance *core_instance, struct cc_state_change_args *args, enum cc_state previous_state)
{
	/* Both caller and callee are available, call agent's recall callback
	 */
	cancel_available_timer(core_instance);
	cc_publish_callerrecalling(core_instance->core_id, core_instance->agent->device_name);
	return 0;
}

static int cc_complete(struct cc_core_instance *core_instance, struct cc_state_change_args *args, enum cc_state previous_state)
{
	/* Recall has made progress, call agent and monitor destructor functions
	 */
	cc_publish_recallcomplete(core_instance->core_id, core_instance->agent->device_name);
	ao2_t_unlink(cc_core_instances, core_instance, "Unlink core instance since CC recall has completed");
	return 0;
}

static int cc_failed(struct cc_core_instance *core_instance, struct cc_state_change_args *args, enum cc_state previous_state)
{
	cc_publish_failure(core_instance->core_id, core_instance->agent->device_name, args->debug);
	ao2_t_unlink(cc_core_instances, core_instance, "Unlink core instance since CC failed");
	return 0;
}

static int (* const state_change_funcs [])(struct cc_core_instance *, struct cc_state_change_args *, enum cc_state previous_state) = {
	[CC_AVAILABLE] = cc_available,
	[CC_CALLER_OFFERED] = cc_caller_offered,
	[CC_CALLER_REQUESTED] = cc_caller_requested,
	[CC_ACTIVE] = cc_active,
	[CC_CALLEE_READY] = cc_callee_ready,
	[CC_CALLER_BUSY] = cc_caller_busy,
	[CC_RECALLING] = cc_recalling,
	[CC_COMPLETE] = cc_complete,
	[CC_FAILED] = cc_failed,
};

static int cc_do_state_change(void *datap)
{
	struct cc_state_change_args *args = datap;
	struct cc_core_instance *core_instance;
	enum cc_state previous_state;
	int res;

	ast_log_dynamic_level(cc_logger_level, "Core %d: State change to %u requested. Reason: %s\n",
			args->core_id, args->state, args->debug);

	core_instance = args->core_instance;

	if (!is_state_change_valid(core_instance->current_state, args->state, core_instance->agent)) {
		ast_log_dynamic_level(cc_logger_level, "Core %d: Invalid state change requested. Cannot go from %s to %s\n",
				args->core_id, cc_state_to_string(core_instance->current_state), cc_state_to_string(args->state));
		if (args->state == CC_CALLER_REQUESTED) {
			/*
			 * For out-of-order requests, we need to let the requester know that
			 * we can't handle the request now.
			 */
			core_instance->agent->callbacks->respond(core_instance->agent,
				AST_CC_AGENT_RESPONSE_FAILURE_INVALID);
		}
		ast_free(args);
		cc_unref(core_instance, "Unref core instance from when it was found earlier");
		return -1;
	}

	/* We can change to the new state now. */
	previous_state = core_instance->current_state;
	core_instance->current_state = args->state;
	res = state_change_funcs[core_instance->current_state](core_instance, args, previous_state);

	/* If state change successful then notify any device state watchers of the change */
	if (!res && !strcmp(core_instance->agent->callbacks->type, "generic")) {
		ccss_notify_device_state_change(core_instance->agent->device_name, core_instance->current_state);
	}

	ast_free(args);
	cc_unref(core_instance, "Unref since state change has completed"); /* From ao2_find */
	return res;
}

static int cc_request_state_change(enum cc_state state, const int core_id, const char *debug, va_list ap)
{
	int res;
	int debuglen;
	char dummy[1];
	va_list aq;
	struct cc_core_instance *core_instance;
	struct cc_state_change_args *args;
	/* This initial call to vsnprintf is simply to find what the
	 * size of the string needs to be
	 */
	va_copy(aq, ap);
	/* We add 1 to the result since vsnprintf's return does not
	 * include the terminating null byte
	 */
	debuglen = vsnprintf(dummy, sizeof(dummy), debug, aq) + 1;
	va_end(aq);

	if (!(args = ast_calloc(1, sizeof(*args) + debuglen))) {
		return -1;
	}

	core_instance = find_cc_core_instance(core_id);
	if (!core_instance) {
		ast_log_dynamic_level(cc_logger_level, "Core %d: Unable to find core instance.\n",
			core_id);
		ast_free(args);
		return -1;
	}

	args->core_instance = core_instance;
	args->state = state;
	args->core_id = core_id;
	vsnprintf(args->debug, debuglen, debug, ap);

	res = ast_taskprocessor_push(cc_core_taskprocessor, cc_do_state_change, args);
	if (res) {
		cc_unref(core_instance, "Unref core instance. ast_taskprocessor_push failed");
		ast_free(args);
	}
	return res;
}

struct cc_recall_ds_data {
	int core_id;
	char ignore;
	char nested;
	struct cc_monitor_tree *interface_tree;
};

static void *cc_recall_ds_duplicate(void *data)
{
	struct cc_recall_ds_data *old_data = data;
	struct cc_recall_ds_data *new_data = ast_calloc(1, sizeof(*new_data));

	if (!new_data) {
		return NULL;
	}
	new_data->interface_tree = cc_ref(old_data->interface_tree, "Bump refcount of monitor tree for recall datastore duplicate");
	new_data->core_id = old_data->core_id;
	new_data->nested = 1;
	return new_data;
}

static void cc_recall_ds_destroy(void *data)
{
	struct cc_recall_ds_data *recall_data = data;
	recall_data->interface_tree = cc_unref(recall_data->interface_tree, "Unref recall monitor tree");
	ast_free(recall_data);
}

static const struct ast_datastore_info recall_ds_info = {
	.type = "cc_recall",
	.duplicate = cc_recall_ds_duplicate,
	.destroy = cc_recall_ds_destroy,
};

int ast_setup_cc_recall_datastore(struct ast_channel *chan, const int core_id)
{
	struct ast_datastore *recall_datastore = ast_datastore_alloc(&recall_ds_info, NULL);
	struct cc_recall_ds_data *recall_data;
	struct cc_core_instance *core_instance;

	if (!recall_datastore) {
		return -1;
	}

	if (!(recall_data = ast_calloc(1, sizeof(*recall_data)))) {
		ast_datastore_free(recall_datastore);
		return -1;
	}

	if (!(core_instance = find_cc_core_instance(core_id))) {
		ast_free(recall_data);
		ast_datastore_free(recall_datastore);
		return -1;
	}

	recall_data->interface_tree = cc_ref(core_instance->monitors,
			"Bump refcount for monitor tree for recall datastore");
	recall_data->core_id = core_id;
	recall_datastore->data = recall_data;
	recall_datastore->inheritance = DATASTORE_INHERIT_FOREVER;
	ast_channel_lock(chan);
	ast_channel_datastore_add(chan, recall_datastore);
	ast_channel_unlock(chan);
	cc_unref(core_instance, "Recall datastore set up. No need for core_instance ref");
	return 0;
}

int ast_cc_is_recall(struct ast_channel *chan, int *core_id, const char * const monitor_type)
{
	struct ast_datastore *recall_datastore;
	struct cc_recall_ds_data *recall_data;
	struct cc_monitor_tree *interface_tree;
	char device_name[AST_CHANNEL_NAME];
	struct ast_cc_monitor *device_monitor;
	int core_id_candidate;

	ast_assert(core_id != NULL);

	*core_id = -1;

	ast_channel_lock(chan);
	if (!(recall_datastore = ast_channel_datastore_find(chan, &recall_ds_info, NULL))) {
		/* Obviously not a recall if the datastore isn't present */
		ast_channel_unlock(chan);
		return 0;
	}

	recall_data = recall_datastore->data;

	if (recall_data->ignore) {
		/* Though this is a recall, the call to this particular interface is not part of the
		 * recall either because this is a call forward or because this is not the first
		 * invocation of Dial during this call
		 */
		ast_channel_unlock(chan);
		return 0;
	}

	if (!recall_data->nested) {
		/* If the nested flag is not set, then this means that
		 * the channel passed to this function is the caller making
		 * the recall. This means that we shouldn't look through
		 * the monitor tree for the channel because it shouldn't be
		 * there. However, this is a recall though, so return true.
		 */
		*core_id = recall_data->core_id;
		ast_channel_unlock(chan);
		return 1;
	}

	if (ast_strlen_zero(monitor_type)) {
		/* If someone passed a NULL or empty monitor type, then it is clear
		 * the channel they passed in was an incoming channel, and so searching
		 * the list of dialed interfaces is not going to be helpful. Just return
		 * false immediately.
		 */
		ast_channel_unlock(chan);
		return 0;
	}

	interface_tree = recall_data->interface_tree;
	ast_channel_get_device_name(chan, device_name, sizeof(device_name));
	/* We grab the value of the recall_data->core_id so that we
	 * can unlock the channel before we start looking through the
	 * interface list. That way we don't have to worry about a possible
	 * clash between the channel lock and the monitor tree lock.
	 */
	core_id_candidate = recall_data->core_id;
	ast_channel_unlock(chan);

	/*
	 * Now we need to find out if the channel device name
	 * is in the list of interfaces in the called tree.
	 */
	AST_LIST_LOCK(interface_tree);
	AST_LIST_TRAVERSE(interface_tree, device_monitor, next) {
		if (!strcmp(device_monitor->interface->device_name, device_name) &&
				!strcmp(device_monitor->interface->monitor_type, monitor_type)) {
			/* BOOM! Device is in the tree! We have a winner! */
			*core_id = core_id_candidate;
			AST_LIST_UNLOCK(interface_tree);
			return 1;
		}
	}
	AST_LIST_UNLOCK(interface_tree);
	return 0;
}

struct ast_cc_monitor *ast_cc_get_monitor_by_recall_core_id(const int core_id, const char * const device_name)
{
	struct cc_core_instance *core_instance = find_cc_core_instance(core_id);
	struct ast_cc_monitor *monitor_iter;

	if (!core_instance) {
		return NULL;
	}

	AST_LIST_LOCK(core_instance->monitors);
	AST_LIST_TRAVERSE(core_instance->monitors, monitor_iter, next) {
		if (!strcmp(monitor_iter->interface->device_name, device_name)) {
			/* Found a monitor. */
			cc_ref(monitor_iter, "Hand the requester of the monitor a reference");
			break;
		}
	}
	AST_LIST_UNLOCK(core_instance->monitors);
	cc_unref(core_instance, "Done with core instance ref in ast_cc_get_monitor_by_recall_core_id");
	return monitor_iter;
}

/*!
 * \internal
 * \brief uniquely append a dialstring to our CC_INTERFACES chanvar string.
 *
 * We will only append a string if it has not already appeared in our channel
 * variable earlier. We ensure that we don't erroneously match substrings by
 * adding an ampersand to the end of our potential dialstring and searching for
 * it plus the ampersand in our variable.
 *
 * It's important to note that once we have built the full CC_INTERFACES string,
 * there will be an extra ampersand at the end which must be stripped off by
 * the caller of this function.
 *
 * \param str An ast_str holding what we will add to CC_INTERFACES
 * \param dialstring A new dialstring to add
 * \retval void
 */
static void cc_unique_append(struct ast_str **str, const char *dialstring)
{
	char dialstring_search[AST_CHANNEL_NAME + 1];

	if (ast_strlen_zero(dialstring)) {
		/* No dialstring to append. */
		return;
	}
	snprintf(dialstring_search, sizeof(dialstring_search), "%s%c", dialstring, '&');
	if (strstr(ast_str_buffer(*str), dialstring_search)) {
		return;
	}
	ast_str_append(str, 0, "%s", dialstring_search);
}

/*!
 * \internal
 * \brief Build the CC_INTERFACES channel variable
 *
 * The method used is to traverse the child dialstrings in the
 * passed-in extension monitor, adding any that have the is_valid
 * flag set. Then, traverse the monitors, finding all children
 * of the starting extension monitor and adding their dialstrings
 * as well.
 *
 * \param starting_point The extension monitor that is the parent to all
 * monitors whose dialstrings should be added to CC_INTERFACES
 * \param str Where we will store CC_INTERFACES
 * \retval void
 */
static void build_cc_interfaces_chanvar(struct ast_cc_monitor *starting_point, struct ast_str **str)
{
	struct extension_monitor_pvt *extension_pvt;
	struct extension_child_dialstring *child_dialstring;
	struct ast_cc_monitor *monitor_iter = starting_point;
	int top_level_id = starting_point->id;
	size_t length;

	/* Init to an empty string. */
	ast_str_truncate(*str, 0);

	/* First we need to take all of the is_valid child_dialstrings from
	 * the extension monitor we found and add them to the CC_INTERFACES
	 * chanvar
	 */
	extension_pvt = starting_point->private_data;
	AST_LIST_TRAVERSE(&extension_pvt->child_dialstrings, child_dialstring, next) {
		if (child_dialstring->is_valid) {
			cc_unique_append(str, child_dialstring->original_dialstring);
		}
	}

	/* And now we get the dialstrings from each of the device monitors */
	while ((monitor_iter = AST_LIST_NEXT(monitor_iter, next))) {
		if (monitor_iter->parent_id == top_level_id) {
			cc_unique_append(str, monitor_iter->dialstring);
		}
	}

	/* str will have an extra '&' tacked onto the end of it, so we need
	 * to get rid of that.
	 */
	length = ast_str_strlen(*str);
	if (length) {
		ast_str_truncate(*str, length - 1);
	}
	if (length <= 1) {
		/* Nothing to recall?  This should not happen. */
		ast_log(LOG_ERROR, "CC_INTERFACES is empty. starting device_name:'%s'\n",
			starting_point->interface->device_name);
	}
}

int ast_cc_agent_set_interfaces_chanvar(struct ast_channel *chan)
{
	struct ast_datastore *recall_datastore;
	struct cc_monitor_tree *interface_tree;
	struct ast_cc_monitor *monitor;
	struct cc_recall_ds_data *recall_data;
	struct ast_str *str = ast_str_create(64);
	int core_id;

	if (!str) {
		return -1;
	}

	ast_channel_lock(chan);
	if (!(recall_datastore = ast_channel_datastore_find(chan, &recall_ds_info, NULL))) {
		ast_channel_unlock(chan);
		ast_free(str);
		return -1;
	}
	recall_data = recall_datastore->data;
	interface_tree = recall_data->interface_tree;
	core_id = recall_data->core_id;
	ast_channel_unlock(chan);

	AST_LIST_LOCK(interface_tree);
	monitor = AST_LIST_FIRST(interface_tree);
	build_cc_interfaces_chanvar(monitor, &str);
	AST_LIST_UNLOCK(interface_tree);

	pbx_builtin_setvar_helper(chan, "CC_INTERFACES", ast_str_buffer(str));
	ast_log_dynamic_level(cc_logger_level, "Core %d: CC_INTERFACES set to %s\n",
			core_id, ast_str_buffer(str));

	ast_free(str);
	return 0;
}

int ast_set_cc_interfaces_chanvar(struct ast_channel *chan, const char * const extension)
{
	struct ast_datastore *recall_datastore;
	struct cc_monitor_tree *interface_tree;
	struct ast_cc_monitor *monitor_iter;
	struct cc_recall_ds_data *recall_data;
	struct ast_str *str = ast_str_create(64);
	int core_id;

	if (!str) {
		return -1;
	}

	ast_channel_lock(chan);
	if (!(recall_datastore = ast_channel_datastore_find(chan, &recall_ds_info, NULL))) {
		ast_channel_unlock(chan);
		ast_free(str);
		return -1;
	}
	recall_data = recall_datastore->data;
	interface_tree = recall_data->interface_tree;
	core_id = recall_data->core_id;
	ast_channel_unlock(chan);

	AST_LIST_LOCK(interface_tree);
	AST_LIST_TRAVERSE(interface_tree, monitor_iter, next) {
		if (!strcmp(monitor_iter->interface->device_name, extension)) {
			break;
		}
	}

	if (!monitor_iter) {
		/* We couldn't find this extension. This may be because
		 * we have been directed into an unexpected extension because
		 * the admin has changed a CC_INTERFACES variable at some point.
		 */
		AST_LIST_UNLOCK(interface_tree);
		ast_free(str);
		return -1;
	}

	build_cc_interfaces_chanvar(monitor_iter, &str);
	AST_LIST_UNLOCK(interface_tree);

	pbx_builtin_setvar_helper(chan, "CC_INTERFACES", ast_str_buffer(str));
	ast_log_dynamic_level(cc_logger_level, "Core %d: CC_INTERFACES set to %s\n",
			core_id, ast_str_buffer(str));

	ast_free(str);
	return 0;
}

void ast_ignore_cc(struct ast_channel *chan)
{
	struct ast_datastore *cc_datastore;
	struct ast_datastore *cc_recall_datastore;
	struct dialed_cc_interfaces *cc_interfaces;
	struct cc_recall_ds_data *recall_cc_data;

	ast_channel_lock(chan);
	if ((cc_datastore = ast_channel_datastore_find(chan, &dialed_cc_interfaces_info, NULL))) {
		cc_interfaces = cc_datastore->data;
		cc_interfaces->ignore = 1;
	}

	if ((cc_recall_datastore = ast_channel_datastore_find(chan, &recall_ds_info, NULL))) {
		recall_cc_data = cc_recall_datastore->data;
		recall_cc_data->ignore = 1;
	}
	ast_channel_unlock(chan);
}

static __attribute__((format(printf, 2, 3))) int cc_offer(const int core_id, const char * const debug, ...)
{
	va_list ap;
	int res;

	va_start(ap, debug);
	res = cc_request_state_change(CC_CALLER_OFFERED, core_id, debug, ap);
	va_end(ap);
	return res;
}

int ast_cc_offer(struct ast_channel *caller_chan)
{
	int core_id;
	int res = -1;
	struct ast_datastore *datastore;
	struct dialed_cc_interfaces *cc_interfaces;
	char cc_is_offerable;

	ast_channel_lock(caller_chan);
	if (!(datastore = ast_channel_datastore_find(caller_chan, &dialed_cc_interfaces_info, NULL))) {
		ast_channel_unlock(caller_chan);
		return res;
	}

	cc_interfaces = datastore->data;
	cc_is_offerable = cc_interfaces->is_original_caller;
	core_id = cc_interfaces->core_id;
	ast_channel_unlock(caller_chan);

	if (cc_is_offerable) {
		res = cc_offer(core_id, "CC offered to caller %s", ast_channel_name(caller_chan));
	}
	return res;
}

int ast_cc_agent_accept_request(int core_id, const char * const debug, ...)
{
	va_list ap;
	int res;

	va_start(ap, debug);
	res = cc_request_state_change(CC_CALLER_REQUESTED, core_id, debug, ap);
	va_end(ap);
	return res;
}

int ast_cc_monitor_request_acked(int core_id, const char * const debug, ...)
{
	va_list ap;
	int res;

	va_start(ap, debug);
	res = cc_request_state_change(CC_ACTIVE, core_id, debug, ap);
	va_end(ap);
	return res;
}

int ast_cc_monitor_callee_available(const int core_id, const char * const debug, ...)
{
	va_list ap;
	int res;

	va_start(ap, debug);
	res = cc_request_state_change(CC_CALLEE_READY, core_id, debug, ap);
	va_end(ap);
	return res;
}

int ast_cc_agent_caller_busy(int core_id, const char * debug, ...)
{
	va_list ap;
	int res;

	va_start(ap, debug);
	res = cc_request_state_change(CC_CALLER_BUSY, core_id, debug, ap);
	va_end(ap);
	return res;
}

int ast_cc_agent_caller_available(int core_id, const char * const debug, ...)
{
	va_list ap;
	int res;

	va_start(ap, debug);
	res = cc_request_state_change(CC_ACTIVE, core_id, debug, ap);
	va_end(ap);
	return res;
}

int ast_cc_agent_recalling(int core_id, const char * const debug, ...)
{
	va_list ap;
	int res;

	va_start(ap, debug);
	res = cc_request_state_change(CC_RECALLING, core_id, debug, ap);
	va_end(ap);
	return res;
}

int ast_cc_completed(struct ast_channel *chan, const char * const debug, ...)
{
	struct ast_datastore *recall_datastore;
	struct cc_recall_ds_data *recall_data;
	int core_id;
	va_list ap;
	int res;

	ast_channel_lock(chan);
	if (!(recall_datastore = ast_channel_datastore_find(chan, &recall_ds_info, NULL))) {
		/* Silly! Why did you call this function if there's no recall DS? */
		ast_channel_unlock(chan);
		return -1;
	}
	recall_data = recall_datastore->data;
	if (recall_data->nested || recall_data->ignore) {
		/* If this is being called from a nested Dial, it is too
		 * early to determine if the recall has actually completed.
		 * The outermost dial is the only one with the authority to
		 * declare the recall to be complete.
		 *
		 * Similarly, if this function has been called when the
		 * recall has progressed beyond the first dial, this is not
		 * a legitimate time to declare the recall to be done. In fact,
		 * that should have been done already.
		 */
		ast_channel_unlock(chan);
		return -1;
	}
	core_id = recall_data->core_id;
	ast_channel_unlock(chan);
	va_start(ap, debug);
	res = cc_request_state_change(CC_COMPLETE, core_id, debug, ap);
	va_end(ap);
	return res;
}

int ast_cc_failed(int core_id, const char * const debug, ...)
{
	va_list ap;
	int res;

	va_start(ap, debug);
	res = cc_request_state_change(CC_FAILED, core_id, debug, ap);
	va_end(ap);
	return res;
}

struct ast_cc_monitor_failure_data {
	const char *device_name;
	char *debug;
	int core_id;
};

static int cc_monitor_failed(void *data)
{
	struct ast_cc_monitor_failure_data *failure_data = data;
	struct cc_core_instance *core_instance;
	struct ast_cc_monitor *monitor_iter;

	core_instance = find_cc_core_instance(failure_data->core_id);
	if (!core_instance) {
		/* Core instance no longer exists or invalid core_id. */
		ast_log_dynamic_level(cc_logger_level,
			"Core %d: Could not find core instance for device %s '%s'\n",
			failure_data->core_id, failure_data->device_name, failure_data->debug);
		ast_free((char *) failure_data->device_name);
		ast_free((char *) failure_data->debug);
		ast_free(failure_data);
		return -1;
	}

	AST_LIST_LOCK(core_instance->monitors);
	AST_LIST_TRAVERSE_SAFE_BEGIN(core_instance->monitors, monitor_iter, next) {
		if (monitor_iter->interface->monitor_class == AST_CC_DEVICE_MONITOR) {
			if (!strcmp(monitor_iter->interface->device_name, failure_data->device_name)) {
				AST_LIST_REMOVE_CURRENT(next);
				cc_extension_monitor_change_is_valid(core_instance, monitor_iter->parent_id,
						monitor_iter->interface->device_name, 1);
				monitor_iter->callbacks->cancel_available_timer(monitor_iter, &monitor_iter->available_timer_id);
				cc_publish_monitorfailed(monitor_iter->core_id, monitor_iter->interface->device_name);
				cc_unref(monitor_iter, "Monitor reported failure. Unref list's reference.");
			}
		}
	}
	AST_LIST_TRAVERSE_SAFE_END;

	if (!has_device_monitors(core_instance)) {
		ast_cc_failed(core_instance->core_id, "All monitors have failed\n");
	}
	AST_LIST_UNLOCK(core_instance->monitors);
	cc_unref(core_instance, "Finished with core_instance in cc_monitor_failed\n");

	ast_free((char *) failure_data->device_name);
	ast_free((char *) failure_data->debug);
	ast_free(failure_data);
	return 0;
}

int ast_cc_monitor_failed(int core_id, const char *const monitor_name, const char * const debug, ...)
{
	struct ast_cc_monitor_failure_data *failure_data;
	int res;
	va_list ap;

	if (!(failure_data = ast_calloc(1, sizeof(*failure_data)))) {
		return -1;
	}

	if (!(failure_data->device_name = ast_strdup(monitor_name))) {
		ast_free(failure_data);
		return -1;
	}

	va_start(ap, debug);
	if (ast_vasprintf(&failure_data->debug, debug, ap) == -1) {
		va_end(ap);
		ast_free((char *)failure_data->device_name);
		ast_free(failure_data);
		return -1;
	}
	va_end(ap);

	failure_data->core_id = core_id;

	res = ast_taskprocessor_push(cc_core_taskprocessor, cc_monitor_failed, failure_data);
	if (res) {
		ast_free((char *)failure_data->device_name);
		ast_free((char *)failure_data->debug);
		ast_free(failure_data);
	}
	return res;
}

static int cc_status_request(void *data)
{
	struct cc_core_instance *core_instance= data;
	int res;

	res = core_instance->agent->callbacks->status_request(core_instance->agent);
	cc_unref(core_instance, "Status request finished. Unref core instance");
	return res;
}

int ast_cc_monitor_status_request(int core_id)
{
	int res;
	struct cc_core_instance *core_instance = find_cc_core_instance(core_id);

	if (!core_instance) {
		return -1;
	}

	res = ast_taskprocessor_push(cc_core_taskprocessor, cc_status_request, core_instance);
	if (res) {
		cc_unref(core_instance, "Unref core instance. ast_taskprocessor_push failed");
	}
	return res;
}

static int cc_stop_ringing(void *data)
{
	struct cc_core_instance *core_instance = data;
	int res = 0;

	if (core_instance->agent->callbacks->stop_ringing) {
		res = core_instance->agent->callbacks->stop_ringing(core_instance->agent);
	}
	/* If an agent is being asked to stop ringing, then he needs to be prepared if for
	 * whatever reason he needs to be called back again. The proper state to be in to
	 * detect such a circumstance is the CC_ACTIVE state.
	 *
	 * We get to this state using the slightly unintuitive method of calling
	 * ast_cc_monitor_request_acked because it gets us to the proper state.
	 */
	ast_cc_monitor_request_acked(core_instance->core_id, "Agent %s asked to stop ringing. Be prepared to be recalled again.",
			core_instance->agent->device_name);
	cc_unref(core_instance, "Stop ringing finished. Unref core_instance");
	return res;
}

int ast_cc_monitor_stop_ringing(int core_id)
{
	int res;
	struct cc_core_instance *core_instance = find_cc_core_instance(core_id);

	if (!core_instance) {
		return -1;
	}

	res = ast_taskprocessor_push(cc_core_taskprocessor, cc_stop_ringing, core_instance);
	if (res) {
		cc_unref(core_instance, "Unref core instance. ast_taskprocessor_push failed");
	}
	return res;
}

static int cc_party_b_free(void *data)
{
	struct cc_core_instance *core_instance = data;
	int res = 0;

	if (core_instance->agent->callbacks->party_b_free) {
		res = core_instance->agent->callbacks->party_b_free(core_instance->agent);
	}
	cc_unref(core_instance, "Party B free finished. Unref core_instance");
	return res;
}

int ast_cc_monitor_party_b_free(int core_id)
{
	int res;
	struct cc_core_instance *core_instance = find_cc_core_instance(core_id);

	if (!core_instance) {
		return -1;
	}

	res = ast_taskprocessor_push(cc_core_taskprocessor, cc_party_b_free, core_instance);
	if (res) {
		cc_unref(core_instance, "Unref core instance. ast_taskprocessor_push failed");
	}
	return res;
}

struct cc_status_response_args {
	struct cc_core_instance *core_instance;
	enum ast_device_state devstate;
};

static int cc_status_response(void *data)
{
	struct cc_status_response_args *args = data;
	struct cc_core_instance *core_instance = args->core_instance;
	struct ast_cc_monitor *monitor_iter;
	enum ast_device_state devstate = args->devstate;

	ast_free(args);

	AST_LIST_LOCK(core_instance->monitors);
	AST_LIST_TRAVERSE(core_instance->monitors, monitor_iter, next) {
		if (monitor_iter->interface->monitor_class == AST_CC_DEVICE_MONITOR &&
				monitor_iter->callbacks->status_response) {
			monitor_iter->callbacks->status_response(monitor_iter, devstate);
		}
	}
	AST_LIST_UNLOCK(core_instance->monitors);
	cc_unref(core_instance, "Status response finished. Unref core instance");
	return 0;
}

int ast_cc_agent_status_response(int core_id, enum ast_device_state devstate)
{
	struct cc_status_response_args *args;
	struct cc_core_instance *core_instance;
	int res;

	args = ast_calloc(1, sizeof(*args));
	if (!args) {
		return -1;
	}

	core_instance = find_cc_core_instance(core_id);
	if (!core_instance) {
		ast_free(args);
		return -1;
	}

	args->core_instance = core_instance;
	args->devstate = devstate;

	res = ast_taskprocessor_push(cc_core_taskprocessor, cc_status_response, args);
	if (res) {
		cc_unref(core_instance, "Unref core instance. ast_taskprocessor_push failed");
		ast_free(args);
	}
	return res;
}

static int cc_build_payload(struct ast_channel *chan, struct ast_cc_config_params *cc_params,
	const char *monitor_type, const char * const device_name, const char * dialstring,
	enum ast_cc_service_type service, void *private_data, struct cc_control_payload *payload)
{
	struct ast_datastore *datastore;
	struct dialed_cc_interfaces *cc_interfaces;
	int dial_parent_id;

	ast_channel_lock(chan);
	datastore = ast_channel_datastore_find(chan, &dialed_cc_interfaces_info, NULL);
	if (!datastore) {
		ast_channel_unlock(chan);
		return -1;
	}
	cc_interfaces = datastore->data;
	dial_parent_id = cc_interfaces->dial_parent_id;
	ast_channel_unlock(chan);

	payload->monitor_type = monitor_type;
	payload->private_data = private_data;
	payload->service = service;
	ast_cc_copy_config_params(&payload->config_params, cc_params);
	payload->parent_interface_id = dial_parent_id;
	ast_copy_string(payload->device_name, device_name, sizeof(payload->device_name));
	ast_copy_string(payload->dialstring, dialstring, sizeof(payload->dialstring));
	return 0;
}

int ast_queue_cc_frame(struct ast_channel *chan, const char *monitor_type,
		const char * const dialstring, enum ast_cc_service_type service, void *private_data)
{
	struct ast_frame frame = {0,};
	char device_name[AST_CHANNEL_NAME];
	int retval;
	struct ast_cc_config_params *cc_params;

	cc_params = ast_channel_get_cc_config_params(chan);
	if (!cc_params) {
		return -1;
	}
	ast_channel_get_device_name(chan, device_name, sizeof(device_name));
	if (ast_cc_monitor_count(device_name, monitor_type) >= ast_get_cc_max_monitors(cc_params)) {
		ast_log(LOG_NOTICE, "Not queuing a CC frame for device %s since it already has its maximum monitors allocated\n", device_name);
		return -1;
	}

	if (ast_cc_build_frame(chan, cc_params, monitor_type, device_name, dialstring, service, private_data, &frame)) {
		/* Frame building failed. We can't use this. */
		return -1;
	}
	retval = ast_queue_frame(chan, &frame);
	ast_frfree(&frame);
	return retval;
}

int ast_cc_build_frame(struct ast_channel *chan, struct ast_cc_config_params *cc_params,
	const char *monitor_type, const char * const device_name,
	const char * const dialstring, enum ast_cc_service_type service, void *private_data,
	struct ast_frame *frame)
{
	struct cc_control_payload *payload = ast_calloc(1, sizeof(*payload));

	if (!payload) {
		return -1;
	}
	if (cc_build_payload(chan, cc_params, monitor_type, device_name, dialstring, service, private_data, payload)) {
		/* Something screwed up, we can't make a frame with this */
		ast_free(payload);
		return -1;
	}
	frame->frametype = AST_FRAME_CONTROL;
	frame->subclass.integer = AST_CONTROL_CC;
	frame->data.ptr = payload;
	frame->datalen = sizeof(*payload);
	frame->mallocd = AST_MALLOCD_DATA;
	return 0;
}

void ast_cc_call_failed(struct ast_channel *incoming, struct ast_channel *outgoing, const char * const dialstring)
{
	char device_name[AST_CHANNEL_NAME];
	struct cc_control_payload payload;
	struct ast_cc_config_params *cc_params;

	if (ast_channel_hangupcause(outgoing) != AST_CAUSE_BUSY && ast_channel_hangupcause(outgoing) != AST_CAUSE_CONGESTION) {
		/* It doesn't make sense to try to offer CCBS to the caller if the reason for ast_call
		 * failing is something other than busy or congestion
		 */
		return;
	}

	cc_params = ast_channel_get_cc_config_params(outgoing);
	if (!cc_params) {
		return;
	}
	if (ast_get_cc_monitor_policy(cc_params) != AST_CC_MONITOR_GENERIC) {
		/* This sort of CCBS only works if using generic CC. For native, we would end up sending
		 * a CC request for a non-existent call. The far end will reject this every time
		 */
		return;
	}

	ast_channel_get_device_name(outgoing, device_name, sizeof(device_name));
	if (cc_build_payload(outgoing, cc_params, AST_CC_GENERIC_MONITOR_TYPE, device_name,
		dialstring, AST_CC_CCBS, NULL, &payload)) {
		/* Something screwed up, we can't make a frame with this */
		return;
	}
	ast_handle_cc_control_frame(incoming, outgoing, &payload);
}

void ast_cc_busy_interface(struct ast_channel *inbound, struct ast_cc_config_params *cc_params,
	const char *monitor_type, const char * const device_name, const char * const dialstring, void *private_data)
{
	struct cc_control_payload payload;
	if (cc_build_payload(inbound, cc_params, monitor_type, device_name, dialstring, AST_CC_CCBS, private_data, &payload)) {
		/* Something screwed up. Don't try to handle this payload */
		call_destructor_with_no_monitor(monitor_type, private_data);
		return;
	}
	ast_handle_cc_control_frame(inbound, NULL, &payload);
}

int ast_cc_callback(struct ast_channel *inbound, const char * const tech, const char * const dest, ast_cc_callback_fn callback)
{
	const struct ast_channel_tech *chantech = ast_get_channel_tech(tech);

	if (chantech && chantech->cc_callback) {
		chantech->cc_callback(inbound, dest, callback);
	}

	return 0;
}

static const char *ccreq_app = "CallCompletionRequest";

static int ccreq_exec(struct ast_channel *chan, const char *data)
{
	struct cc_core_instance *core_instance;
	char device_name[AST_CHANNEL_NAME];
	unsigned long match_flags;
	int res;

	ast_channel_get_device_name(chan, device_name, sizeof(device_name));

	match_flags = MATCH_NO_REQUEST;
	if (!(core_instance = ao2_t_callback_data(cc_core_instances, 0, match_agent, device_name, &match_flags, "Find core instance for CallCompletionRequest"))) {
		ast_log_dynamic_level(cc_logger_level, "Couldn't find a core instance for caller %s\n", device_name);
		pbx_builtin_setvar_helper(chan, "CC_REQUEST_RESULT", "FAIL");
		pbx_builtin_setvar_helper(chan, "CC_REQUEST_REASON", "NO_CORE_INSTANCE");
		return 0;
	}

	ast_log_dynamic_level(cc_logger_level, "Core %d: Found core_instance for caller %s\n",
			core_instance->core_id, device_name);

	if (strcmp(core_instance->agent->callbacks->type, "generic")) {
		ast_log_dynamic_level(cc_logger_level, "Core %d: CallCompletionRequest is only for generic agent types.\n",
				core_instance->core_id);
		pbx_builtin_setvar_helper(chan, "CC_REQUEST_RESULT", "FAIL");
		pbx_builtin_setvar_helper(chan, "CC_REQUEST_REASON", "NOT_GENERIC");
		cc_unref(core_instance, "Unref core_instance since CallCompletionRequest was called with native agent");
		return 0;
	}

	if (!ast_cc_request_is_within_limits()) {
		ast_log_dynamic_level(cc_logger_level, "Core %d: CallCompletionRequest failed. Too many requests in the system\n",
				core_instance->core_id);
		ast_cc_failed(core_instance->core_id, "Too many CC requests\n");
		pbx_builtin_setvar_helper(chan, "CC_REQUEST_RESULT", "FAIL");
		pbx_builtin_setvar_helper(chan, "CC_REQUEST_REASON", "TOO_MANY_REQUESTS");
		cc_unref(core_instance, "Unref core_instance since too many CC requests");
		return 0;
	}

	res = ast_cc_agent_accept_request(core_instance->core_id, "CallCompletionRequest called by caller %s for core_id %d", device_name, core_instance->core_id);
	pbx_builtin_setvar_helper(chan, "CC_REQUEST_RESULT", res ? "FAIL" : "SUCCESS");
	if (res) {
		pbx_builtin_setvar_helper(chan, "CC_REQUEST_REASON", "UNSPECIFIED");
	}

	cc_unref(core_instance, "Done with CallCompletionRequest");
	return 0;
}

static const char *cccancel_app = "CallCompletionCancel";

static int cccancel_exec(struct ast_channel *chan, const char *data)
{
	struct cc_core_instance *core_instance;
	char device_name[AST_CHANNEL_NAME];
	unsigned long match_flags;
	int res;

	ast_channel_get_device_name(chan, device_name, sizeof(device_name));

	match_flags = MATCH_REQUEST;
	if (!(core_instance = ao2_t_callback_data(cc_core_instances, 0, match_agent, device_name, &match_flags, "Find core instance for CallCompletionCancel"))) {
		ast_log_dynamic_level(cc_logger_level, "Cannot find CC transaction to cancel for caller %s\n", device_name);
		pbx_builtin_setvar_helper(chan, "CC_CANCEL_RESULT", "FAIL");
		pbx_builtin_setvar_helper(chan, "CC_CANCEL_REASON", "NO_CORE_INSTANCE");
		return 0;
	}

	if (strcmp(core_instance->agent->callbacks->type, "generic")) {
		ast_log(LOG_WARNING, "CallCompletionCancel may only be used for calles with a generic agent\n");
		cc_unref(core_instance, "Unref core instance found during CallCompletionCancel");
		pbx_builtin_setvar_helper(chan, "CC_CANCEL_RESULT", "FAIL");
		pbx_builtin_setvar_helper(chan, "CC_CANCEL_REASON", "NOT_GENERIC");
		return 0;
	}
	res = ast_cc_failed(core_instance->core_id, "Call completion request Cancelled for core ID %d by caller %s",
			core_instance->core_id, device_name);
	cc_unref(core_instance, "Unref core instance found during CallCompletionCancel");
	pbx_builtin_setvar_helper(chan, "CC_CANCEL_RESULT", res ? "FAIL" : "SUCCESS");
	if (res) {
		pbx_builtin_setvar_helper(chan, "CC_CANCEL_REASON", "UNSPECIFIED");
	}
	return 0;
}

struct count_monitors_cb_data {
	const char *device_name;
	const char *monitor_type;
	int count;
};

static int count_monitors_cb(void *obj, void *arg, int flags)
{
	struct cc_core_instance *core_instance = obj;
	struct count_monitors_cb_data *cb_data = arg;
	const char *device_name = cb_data->device_name;
	const char *monitor_type = cb_data->monitor_type;
	struct ast_cc_monitor *monitor_iter;

	AST_LIST_LOCK(core_instance->monitors);
	AST_LIST_TRAVERSE(core_instance->monitors, monitor_iter, next) {
		if (!strcmp(monitor_iter->interface->device_name, device_name) &&
				!strcmp(monitor_iter->interface->monitor_type, monitor_type)) {
			cb_data->count++;
			break;
		}
	}
	AST_LIST_UNLOCK(core_instance->monitors);
	return 0;
}

int ast_cc_monitor_count(const char * const name, const char * const type)
{
	struct count_monitors_cb_data data = {.device_name = name, .monitor_type = type,};

	ao2_t_callback(cc_core_instances, OBJ_NODATA, count_monitors_cb, &data, "Counting agents");
	ast_log_dynamic_level(cc_logger_level, "Counted %d monitors\n", data.count);
	return data.count;
}

static void initialize_cc_max_requests(void)
{
	struct ast_config *cc_config;
	const char *cc_max_requests_str;
	struct ast_flags config_flags = {0,};
	char *endptr;

	cc_config = ast_config_load2("ccss.conf", "ccss", config_flags);
	if (!cc_config || cc_config == CONFIG_STATUS_FILEINVALID) {
		ast_log(LOG_WARNING, "Could not find valid ccss.conf file. Using cc_max_requests default\n");
		global_cc_max_requests = GLOBAL_CC_MAX_REQUESTS_DEFAULT;
		return;
	}

	if (!(cc_max_requests_str = ast_variable_retrieve(cc_config, "general", "cc_max_requests"))) {
		ast_config_destroy(cc_config);
		global_cc_max_requests = GLOBAL_CC_MAX_REQUESTS_DEFAULT;
		return;
	}

	global_cc_max_requests = strtol(cc_max_requests_str, &endptr, 10);

	if (!ast_strlen_zero(endptr)) {
		ast_log(LOG_WARNING, "Invalid input given for cc_max_requests. Using default\n");
		global_cc_max_requests = GLOBAL_CC_MAX_REQUESTS_DEFAULT;
	}

	ast_config_destroy(cc_config);
	return;
}

/*!
 * \internal
 * \brief helper function to parse and configure each devstate map
 */
static void initialize_cc_devstate_map_helper(struct ast_config *cc_config, enum cc_state state, const char *cc_setting)
{
	const char *cc_devstate_str;
	enum ast_device_state this_devstate;

	if ((cc_devstate_str = ast_variable_retrieve(cc_config, "general", cc_setting))) {
		this_devstate = ast_devstate_val(cc_devstate_str);
		if (this_devstate != AST_DEVICE_UNKNOWN) {
			cc_state_to_devstate_map[state] = this_devstate;
		}
	}
}

/*!
 * \internal
 * \brief initializes cc_state_to_devstate_map from ccss.conf
 *
 * \details
 * The cc_state_to_devstate_map[] is already initialized with all the
 * default values. This will update that structure with any changes
 * from the ccss.conf file. The configuration parameters in ccss.conf
 * should use any valid device state form that is recognized by
 * ast_devstate_val() function.
 */
static void initialize_cc_devstate_map(void)
{
	struct ast_config *cc_config;
	struct ast_flags config_flags = { 0, };

	cc_config = ast_config_load2("ccss.conf", "ccss", config_flags);
	if (!cc_config || cc_config == CONFIG_STATUS_FILEINVALID) {
		ast_log(LOG_WARNING,
			"Could not find valid ccss.conf file. Using cc_[state]_devstate defaults\n");
		return;
	}

	initialize_cc_devstate_map_helper(cc_config, CC_AVAILABLE, "cc_available_devstate");
	initialize_cc_devstate_map_helper(cc_config, CC_CALLER_OFFERED, "cc_caller_offered_devstate");
	initialize_cc_devstate_map_helper(cc_config, CC_CALLER_REQUESTED, "cc_caller_requested_devstate");
	initialize_cc_devstate_map_helper(cc_config, CC_ACTIVE, "cc_active_devstate");
	initialize_cc_devstate_map_helper(cc_config, CC_CALLEE_READY, "cc_callee_ready_devstate");
	initialize_cc_devstate_map_helper(cc_config, CC_CALLER_BUSY, "cc_caller_busy_devstate");
	initialize_cc_devstate_map_helper(cc_config, CC_RECALLING, "cc_recalling_devstate");
	initialize_cc_devstate_map_helper(cc_config, CC_COMPLETE, "cc_complete_devstate");
	initialize_cc_devstate_map_helper(cc_config, CC_FAILED, "cc_failed_devstate");

	ast_config_destroy(cc_config);
}

static void cc_cli_print_monitor_stats(struct ast_cc_monitor *monitor, int fd, int parent_id)
{
	struct ast_cc_monitor *child_monitor_iter = monitor;
	if (!monitor) {
		return;
	}

	ast_cli(fd, "\t\t|-->%s", monitor->interface->device_name);
	if (monitor->interface->monitor_class == AST_CC_DEVICE_MONITOR) {
		ast_cli(fd, "(%s)", cc_service_to_string(monitor->service_offered));
	}
	ast_cli(fd, "\n");

	while ((child_monitor_iter = AST_LIST_NEXT(child_monitor_iter, next))) {
		if (child_monitor_iter->parent_id == monitor->id) {
			cc_cli_print_monitor_stats(child_monitor_iter, fd, child_monitor_iter->id);
		}
	}
}

static int print_stats_cb(void *obj, void *arg, int flags)
{
	int *cli_fd = arg;
	struct cc_core_instance *core_instance = obj;

	ast_cli(*cli_fd, "%d\t\t%s\t\t%s\n", core_instance->core_id, core_instance->agent->device_name,
			cc_state_to_string(core_instance->current_state));
	AST_LIST_LOCK(core_instance->monitors);
	cc_cli_print_monitor_stats(AST_LIST_FIRST(core_instance->monitors), *cli_fd, 0);
	AST_LIST_UNLOCK(core_instance->monitors);
	return 0;
}

static int cc_cli_output_status(void *data)
{
	int *cli_fd = data;
	int count = ao2_container_count(cc_core_instances);

	if (!count) {
		ast_cli(*cli_fd, "There are currently no active call completion transactions\n");
	} else {
		ast_cli(*cli_fd, "%d Call completion transactions\n", count);
		ast_cli(*cli_fd, "Core ID\t\tCaller\t\t\t\tStatus\n");
		ast_cli(*cli_fd, "----------------------------------------------------------------------------\n");
		ao2_t_callback(cc_core_instances, OBJ_NODATA, print_stats_cb, cli_fd, "Printing stats to CLI");
	}
	ast_free(cli_fd);
	return 0;
}

static char *handle_cc_status(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
	int *cli_fd;

	switch (cmd) {
	case CLI_INIT:
		e->command = "cc report status";
		e->usage =
			"Usage: cc report status\n"
			"       Report the current status of any ongoing CC transactions\n";
		return NULL;
	case CLI_GENERATE:
		return NULL;
	}

	if (a->argc != 3) {
		return CLI_SHOWUSAGE;
	}

	cli_fd = ast_malloc(sizeof(*cli_fd));
	if (!cli_fd) {
		return CLI_FAILURE;
	}

	*cli_fd = a->fd;

	if (ast_taskprocessor_push(cc_core_taskprocessor, cc_cli_output_status, cli_fd)) {
		ast_free(cli_fd);
		return CLI_FAILURE;
	}
	return CLI_SUCCESS;
}

static int kill_cores(void *obj, void *arg, int flags)
{
	int *core_id = arg;
	struct cc_core_instance *core_instance = obj;

	if (!core_id || (core_instance->core_id == *core_id)) {
		ast_cc_failed(core_instance->core_id, "CC transaction canceled administratively\n");
	}
	return 0;
}

static char *complete_core_id(const char *word)
{
	int wordlen = strlen(word);
	struct ao2_iterator core_iter = ao2_iterator_init(cc_core_instances, 0);
	struct cc_core_instance *core_instance;

	for (; (core_instance = ao2_t_iterator_next(&core_iter, "Next core instance"));
			cc_unref(core_instance, "CLI tab completion iteration")) {
		char core_id_str[20];
		snprintf(core_id_str, sizeof(core_id_str), "%d", core_instance->core_id);
		if (!strncmp(word, core_id_str, wordlen)) {
			if (ast_cli_completion_add(ast_strdup(core_id_str))) {
				cc_unref(core_instance, "Found a matching core ID for CLI tab-completion");
				break;
			}
		}
	}
	ao2_iterator_destroy(&core_iter);

	return NULL;
}

static char *handle_cc_kill(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
	switch (cmd) {
	case CLI_INIT:
		e->command = "cc cancel [core|all]";
		e->usage =
			"Usage: cc cancel can be used in two ways.\n"
			"       1. 'cc cancel core [core ID]' will cancel the CC transaction with\n"
			"          core ID equal to the specified core ID.\n"
			"       2. 'cc cancel all' will cancel all active CC transactions.\n";
		return NULL;
	case CLI_GENERATE:
		if (a->pos == 3 && !strcasecmp(a->argv[2], "core")) {
			return complete_core_id(a->word);
		}
		return NULL;
	}

	if (a->argc == 4) {
		int core_id;
		char *endptr;
		if (strcasecmp(a->argv[2], "core")) {
			return CLI_SHOWUSAGE;
		}
		core_id = strtol(a->argv[3], &endptr, 10);
		if ((errno != 0 && core_id == 0) || (endptr == a->argv[3])) {
			return CLI_SHOWUSAGE;
		}
		ao2_t_callback(cc_core_instances, OBJ_NODATA, kill_cores, &core_id, "CLI Killing Core Id");
	} else if (a->argc == 3) {
		if (strcasecmp(a->argv[2], "all")) {
			return CLI_SHOWUSAGE;
		}
		ao2_t_callback(cc_core_instances, OBJ_NODATA, kill_cores, NULL, "CLI Killing all CC cores");
	} else {
		return CLI_SHOWUSAGE;
	}

	return CLI_SUCCESS;
}

static struct ast_cli_entry cc_cli[] = {
	AST_CLI_DEFINE(handle_cc_status, "Reports CC stats"),
	AST_CLI_DEFINE(handle_cc_kill, "Kill a CC transaction"),
};

static int unload_module(void)
{
	ast_devstate_prov_del("ccss");
	ast_cc_agent_unregister(&generic_agent_callbacks);
	ast_cc_monitor_unregister(&generic_monitor_cbs);
	ast_unregister_application(cccancel_app);
	ast_unregister_application(ccreq_app);
	ast_logger_unregister_level(CC_LOGGER_LEVEL_NAME);
	ast_cli_unregister_multiple(cc_cli, ARRAY_LEN(cc_cli));

	if (cc_sched_context) {
		ast_sched_context_destroy(cc_sched_context);
		cc_sched_context = NULL;
	}
	if (cc_core_taskprocessor) {
		cc_core_taskprocessor = ast_taskprocessor_unreference(cc_core_taskprocessor);
	}
	/* Note that core instances must be destroyed prior to the generic_monitors */
	if (cc_core_instances) {
		ao2_t_ref(cc_core_instances, -1, "Unref cc_core_instances container in cc_shutdown");
		cc_core_instances = NULL;
	}
	if (generic_monitors) {
		ao2_t_ref(generic_monitors, -1, "Unref generic_monitor container in cc_shutdown");
		generic_monitors = NULL;
	}

	return 0;
}

static int load_module(void)
{
	int res;

	cc_core_instances = ao2_t_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0,
		CC_CORE_INSTANCES_BUCKETS,
		cc_core_instance_hash_fn, NULL, cc_core_instance_cmp_fn,
		"Create core instance container");
	if (!cc_core_instances) {
		return AST_MODULE_LOAD_FAILURE;
	}

	generic_monitors = ao2_t_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0,
		CC_CORE_INSTANCES_BUCKETS,
		generic_monitor_instance_list_hash_fn, NULL, generic_monitor_instance_list_cmp_fn,
		"Create generic monitor container");
	if (!generic_monitors) {
		return AST_MODULE_LOAD_FAILURE;
	}
	if (!(cc_core_taskprocessor = ast_taskprocessor_get("CCSS_core", TPS_REF_DEFAULT))) {
		return AST_MODULE_LOAD_FAILURE;
	}
	if (!(cc_sched_context = ast_sched_context_create())) {
		return AST_MODULE_LOAD_FAILURE;
	}
	if (ast_sched_start_thread(cc_sched_context)) {
		return AST_MODULE_LOAD_FAILURE;
	}
	res = ast_register_application2(ccreq_app, ccreq_exec, NULL, NULL, NULL);
	res |= ast_register_application2(cccancel_app, cccancel_exec, NULL, NULL, NULL);
	res |= ast_cc_monitor_register(&generic_monitor_cbs);
	res |= ast_cc_agent_register(&generic_agent_callbacks);

	ast_cli_register_multiple(cc_cli, ARRAY_LEN(cc_cli));
	cc_logger_level = ast_logger_register_level(CC_LOGGER_LEVEL_NAME);
	dialed_cc_interface_counter = 1;
	initialize_cc_max_requests();

	/* Read the map and register the device state callback for generic agents */
	initialize_cc_devstate_map();
	res |= ast_devstate_prov_add("ccss", ccss_device_state);

	return res ? AST_MODULE_LOAD_FAILURE : AST_MODULE_LOAD_SUCCESS;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_GLOBAL_SYMBOLS | AST_MODFLAG_LOAD_ORDER, "Call Completion Supplementary Services",
	.support_level = AST_MODULE_SUPPORT_CORE,
	.load = load_module,
	.unload = unload_module,
	.load_pri = AST_MODPRI_CORE,
);