summaryrefslogtreecommitdiffstats
path: root/netwerk/sctp/datachannel/DataChannel.cpp
blob: 19be43d1cda15dd93f40a33a1d7319245a1b7818 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
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
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#include <algorithm>
#include <stdio.h>
#include <stdlib.h>
#if !defined(__Userspace_os_Windows)
#include <arpa/inet.h>
#endif
// usrsctp.h expects to have errno definitions prior to its inclusion.
#include <errno.h>

#define SCTP_DEBUG 1
#define SCTP_STDINT_INCLUDE <stdint.h>

#ifdef _MSC_VER
// Disable "warning C4200: nonstandard extension used : zero-sized array in
//          struct/union"
// ...which the third-party file usrsctp.h runs afoul of.
#pragma warning(push)
#pragma warning(disable:4200)
#endif

#include "usrsctp.h"

#ifdef _MSC_VER
#pragma warning(pop)
#endif

#include "DataChannelLog.h"

#include "nsServiceManagerUtils.h"
#include "nsIObserverService.h"
#include "nsIObserver.h"
#include "mozilla/Services.h"
#include "mozilla/Sprintf.h"
#include "nsProxyRelease.h"
#include "nsThread.h"
#include "nsThreadUtils.h"
#include "nsAutoPtr.h"
#include "nsNetUtil.h"
#include "nsNetCID.h"
#include "mozilla/StaticPtr.h"
#include "mozilla/Unused.h"
#ifdef MOZ_PEERCONNECTION
#include "mtransport/runnable_utils.h"
#endif

#define DATACHANNEL_LOG(args) LOG(args)
#include "DataChannel.h"
#include "DataChannelProtocol.h"

// Let us turn on and off important assertions in non-debug builds
#ifdef DEBUG
#define ASSERT_WEBRTC(x) MOZ_ASSERT((x))
#elif defined(MOZ_WEBRTC_ASSERT_ALWAYS)
#define ASSERT_WEBRTC(x) do { if (!(x)) { MOZ_CRASH(); } } while (0)
#endif

static bool sctp_initialized;

namespace mozilla {

LazyLogModule gDataChannelLog("DataChannel");
static LazyLogModule gSCTPLog("SCTP");

class DataChannelShutdown : public nsIObserver
{
public:
  // This needs to be tied to some form object that is guaranteed to be
  // around (singleton likely) unless we want to shutdown sctp whenever
  // we're not using it (and in which case we'd keep a refcnt'd object
  // ref'd by each DataChannelConnection to release the SCTP usrlib via
  // sctp_finish). Right now, the single instance of this class is
  // owned by the observer service.

  NS_DECL_ISUPPORTS

  DataChannelShutdown() {}

  void Init()
    {
      nsCOMPtr<nsIObserverService> observerService =
        mozilla::services::GetObserverService();
      if (!observerService)
        return;

      nsresult rv = observerService->AddObserver(this,
                                                 "xpcom-will-shutdown",
                                                 false);
      MOZ_ASSERT(rv == NS_OK);
      (void) rv;
    }

private:
  // The only instance of DataChannelShutdown is owned by the observer
  // service, so there is no need to call RemoveObserver here.
  virtual ~DataChannelShutdown() = default;

public:
  NS_IMETHOD Observe(nsISupports* aSubject, const char* aTopic,
                     const char16_t* aData) override {
    if (strcmp(aTopic, "xpcom-will-shutdown") == 0) {
      LOG(("Shutting down SCTP"));
      if (sctp_initialized) {
        usrsctp_finish();
        sctp_initialized = false;
      }
      nsCOMPtr<nsIObserverService> observerService =
        mozilla::services::GetObserverService();
      if (!observerService)
        return NS_ERROR_FAILURE;

      nsresult rv = observerService->RemoveObserver(this,
                                                    "xpcom-will-shutdown");
      MOZ_ASSERT(rv == NS_OK);
      (void) rv;
    }
    return NS_OK;
  }
};

NS_IMPL_ISUPPORTS(DataChannelShutdown, nsIObserver);

BufferedMsg::BufferedMsg(struct sctp_sendv_spa &spa, const char *data,
                         size_t length) : mLength(length)
{
  mSpa = new sctp_sendv_spa;
  *mSpa = spa;
  auto *tmp = new char[length]; // infallible malloc!
  memcpy(tmp, data, length);
  mData = tmp;
}

BufferedMsg::~BufferedMsg()
{
  delete mSpa;
  delete mData;
}

static int
receive_cb(struct socket* sock, union sctp_sockstore addr,
           void *data, size_t datalen,
           struct sctp_rcvinfo rcv, int flags, void *ulp_info)
{
  DataChannelConnection *connection = static_cast<DataChannelConnection*>(ulp_info);
  return connection->ReceiveCallback(sock, data, datalen, rcv, flags);
}

static
DataChannelConnection *
GetConnectionFromSocket(struct socket* sock)
{
  struct sockaddr *addrs = nullptr;
  int naddrs = usrsctp_getladdrs(sock, 0, &addrs);
  if (naddrs <= 0 || addrs[0].sa_family != AF_CONN) {
    return nullptr;
  }
  // usrsctp_getladdrs() returns the addresses bound to this socket, which
  // contains the SctpDataMediaChannel* as sconn_addr.  Read the pointer,
  // then free the list of addresses once we have the pointer.  We only open
  // AF_CONN sockets, and they should all have the sconn_addr set to the
  // pointer that created them, so [0] is as good as any other.
  struct sockaddr_conn *sconn = reinterpret_cast<struct sockaddr_conn *>(&addrs[0]);
  DataChannelConnection *connection =
    reinterpret_cast<DataChannelConnection *>(sconn->sconn_addr);
  usrsctp_freeladdrs(addrs);

  return connection;
}

// called when the buffer empties to the threshold value
static int
threshold_event(struct socket* sock, uint32_t sb_free)
{
  DataChannelConnection *connection = GetConnectionFromSocket(sock);
  if (connection) {
    LOG(("SendDeferred()"));
    connection->SendDeferredMessages();
  } else {
    LOG(("Can't find connection for socket %p", sock));
  }
  return 0;
}

static void
debug_printf(const char *format, ...)
{
  va_list ap;
  char buffer[1024];

  if (MOZ_LOG_TEST(gSCTPLog, LogLevel::Debug)) {
    va_start(ap, format);
#ifdef _WIN32
    if (vsnprintf_s(buffer, sizeof(buffer), _TRUNCATE, format, ap) > 0) {
#else
    if (VsprintfLiteral(buffer, format, ap) > 0) {
#endif
      PR_LogPrint("%s", buffer);
    }
    va_end(ap);
  }
}

DataChannelConnection::DataChannelConnection(DataConnectionListener *listener) :
   mLock("netwerk::sctp::DataChannelConnection")
{
  mState = CLOSED;
  mSocket = nullptr;
  mMasterSocket = nullptr;
  mListener = listener;
  mLocalPort = 0;
  mRemotePort = 0;
  LOG(("Constructor DataChannelConnection=%p, listener=%p", this, mListener.get()));
  mInternalIOThread = nullptr;
}

DataChannelConnection::~DataChannelConnection()
{
  LOG(("Deleting DataChannelConnection %p", (void *) this));
  // This may die on the MainThread, or on the STS thread
  ASSERT_WEBRTC(mState == CLOSED);
  MOZ_ASSERT(!mMasterSocket);
  MOZ_ASSERT(mPending.GetSize() == 0);

  // Already disconnected from sigslot/mTransportFlow
  // TransportFlows must be released from the STS thread
  if (!IsSTSThread()) {
    ASSERT_WEBRTC(NS_IsMainThread());
    if (mTransportFlow) {
      ASSERT_WEBRTC(mSTS);
      NS_ProxyRelease(mSTS, mTransportFlow.forget());
    }

    if (mInternalIOThread) {
      // Avoid spinning the event thread from here (which if we're mainthread
      // is in the event loop already)
      NS_DispatchToMainThread(WrapRunnable(nsCOMPtr<nsIThread>(mInternalIOThread),
                                           &nsIThread::Shutdown),
                              NS_DISPATCH_NORMAL);
    }
  } else {
    // on STS, safe to call shutdown
    if (mInternalIOThread) {
      mInternalIOThread->Shutdown();
    }
  }
}

void
DataChannelConnection::Destroy()
{
  // Though it's probably ok to do this and close the sockets;
  // if we really want it to do true clean shutdowns it can
  // create a dependant Internal object that would remain around
  // until the network shut down the association or timed out.
  LOG(("Destroying DataChannelConnection %p", (void *) this));
  ASSERT_WEBRTC(NS_IsMainThread());
  CloseAll();

  MutexAutoLock lock(mLock);
  // If we had a pending reset, we aren't waiting for it - clear the list so
  // we can deregister this DataChannelConnection without leaking.
  ClearResets();

  MOZ_ASSERT(mSTS);
  ASSERT_WEBRTC(NS_IsMainThread());
  // Must do this in Destroy() since we may then delete this object.
  // Do this before dispatching to create a consistent ordering of calls to
  // the SCTP stack.
  if (mUsingDtls) {
    usrsctp_deregister_address(static_cast<void *>(this));
    LOG(("Deregistered %p from the SCTP stack.", static_cast<void *>(this)));
  }

  mListener = nullptr;
  // Finish Destroy on STS thread to avoid bug 876167 - once that's fixed,
  // the usrsctp_close() calls can move back here (and just proxy the
  // disconnect_all())
  RUN_ON_THREAD(mSTS, WrapRunnable(RefPtr<DataChannelConnection>(this),
                                   &DataChannelConnection::DestroyOnSTS,
                                   mSocket, mMasterSocket),
                NS_DISPATCH_NORMAL);

  // These will be released on STS
  mSocket = nullptr;
  mMasterSocket = nullptr; // also a flag that we've Destroyed this connection

  // We can't get any more new callbacks from the SCTP library
  // All existing callbacks have refs to DataChannelConnection

  // nsDOMDataChannel objects have refs to DataChannels that have refs to us
}

void DataChannelConnection::DestroyOnSTS(struct socket *aMasterSocket,
                                         struct socket *aSocket)
{
  if (aSocket && aSocket != aMasterSocket)
    usrsctp_close(aSocket);
  if (aMasterSocket)
    usrsctp_close(aMasterSocket);

  disconnect_all();
}

bool
DataChannelConnection::Init(unsigned short aPort, uint16_t aNumStreams, bool aUsingDtls)
{
  struct sctp_initmsg initmsg;
  struct sctp_udpencaps encaps;
  struct sctp_assoc_value av;
  struct sctp_event event;
  socklen_t len;

  uint16_t event_types[] = {SCTP_ASSOC_CHANGE,
                            SCTP_PEER_ADDR_CHANGE,
                            SCTP_REMOTE_ERROR,
                            SCTP_SHUTDOWN_EVENT,
                            SCTP_ADAPTATION_INDICATION,
                            SCTP_SEND_FAILED_EVENT,
                            SCTP_STREAM_RESET_EVENT,
                            SCTP_STREAM_CHANGE_EVENT};
  {
    ASSERT_WEBRTC(NS_IsMainThread());

    // MutexAutoLock lock(mLock); Not needed since we're on mainthread always
    if (!sctp_initialized) {
      if (aUsingDtls) {
        LOG(("sctp_init(DTLS)"));
#ifdef MOZ_PEERCONNECTION
        usrsctp_init(0,
                     DataChannelConnection::SctpDtlsOutput,
                     debug_printf
                    );
#else
        NS_ASSERTION(!aUsingDtls, "Trying to use SCTP/DTLS without mtransport");
#endif
      } else {
        LOG(("sctp_init(%u)", aPort));
        usrsctp_init(aPort,
                     nullptr,
                     debug_printf
                    );
      }

      // Set logging to SCTP:LogLevel::Debug to get SCTP debugs
      if (MOZ_LOG_TEST(gSCTPLog, LogLevel::Debug)) {
        usrsctp_sysctl_set_sctp_debug_on(SCTP_DEBUG_ALL);
      }

      usrsctp_sysctl_set_sctp_blackhole(2);
      // ECN is currently not supported by the Firefox code
      usrsctp_sysctl_set_sctp_ecn_enable(0);
      sctp_initialized = true;

      RefPtr<DataChannelShutdown> shutdown = new DataChannelShutdown();
      shutdown->Init();
    }
  }

  // XXX FIX! make this a global we get once
  // Find the STS thread
  nsresult rv;
  mSTS = do_GetService(NS_SOCKETTRANSPORTSERVICE_CONTRACTID, &rv);
  MOZ_ASSERT(NS_SUCCEEDED(rv));

  // Open sctp with a callback
  if ((mMasterSocket = usrsctp_socket(
         aUsingDtls ? AF_CONN : AF_INET,
         SOCK_STREAM, IPPROTO_SCTP, receive_cb, threshold_event,
         usrsctp_sysctl_get_sctp_sendspace() / 2, this)) == nullptr) {
    return false;
  }

  // Make non-blocking for bind/connect.  SCTP over UDP defaults to non-blocking
  // in associations for normal IO
  if (usrsctp_set_non_blocking(mMasterSocket, 1) < 0) {
    LOG(("Couldn't set non_blocking on SCTP socket"));
    // We can't handle connect() safely if it will block, not that this will
    // even happen.
    goto error_cleanup;
  }

  // Make sure when we close the socket, make sure it doesn't call us back again!
  // This would cause it try to use an invalid DataChannelConnection pointer
  struct linger l;
  l.l_onoff = 1;
  l.l_linger = 0;
  if (usrsctp_setsockopt(mMasterSocket, SOL_SOCKET, SO_LINGER,
                         (const void *)&l, (socklen_t)sizeof(struct linger)) < 0) {
    LOG(("Couldn't set SO_LINGER on SCTP socket"));
    // unsafe to allow it to continue if this fails
    goto error_cleanup;
  }

  // XXX Consider disabling this when we add proper SDP negotiation.
  // We may want to leave enabled for supporting 'cloning' of SDP offers, which
  // implies re-use of the same pseudo-port number, or forcing a renegotiation.
  {
    uint32_t on = 1;
    if (usrsctp_setsockopt(mMasterSocket, IPPROTO_SCTP, SCTP_REUSE_PORT,
                           (const void *)&on, (socklen_t)sizeof(on)) < 0) {
      LOG(("Couldn't set SCTP_REUSE_PORT on SCTP socket"));
    }
    if (usrsctp_setsockopt(mMasterSocket, IPPROTO_SCTP, SCTP_NODELAY,
                           (const void *)&on, (socklen_t)sizeof(on)) < 0) {
      LOG(("Couldn't set SCTP_NODELAY on SCTP socket"));
    }
  }

  if (!aUsingDtls) {
    memset(&encaps, 0, sizeof(encaps));
    encaps.sue_address.ss_family = AF_INET;
    encaps.sue_port = htons(aPort);
    if (usrsctp_setsockopt(mMasterSocket, IPPROTO_SCTP, SCTP_REMOTE_UDP_ENCAPS_PORT,
                           (const void*)&encaps,
                           (socklen_t)sizeof(struct sctp_udpencaps)) < 0) {
      LOG(("*** failed encaps errno %d", errno));
      goto error_cleanup;
    }
    LOG(("SCTP encapsulation local port %d", aPort));
  }

  av.assoc_id = SCTP_ALL_ASSOC;
  av.assoc_value = SCTP_ENABLE_RESET_STREAM_REQ | SCTP_ENABLE_CHANGE_ASSOC_REQ;
  if (usrsctp_setsockopt(mMasterSocket, IPPROTO_SCTP, SCTP_ENABLE_STREAM_RESET, &av,
                         (socklen_t)sizeof(struct sctp_assoc_value)) < 0) {
    LOG(("*** failed enable stream reset errno %d", errno));
    goto error_cleanup;
  }

  /* Enable the events of interest. */
  memset(&event, 0, sizeof(event));
  event.se_assoc_id = SCTP_ALL_ASSOC;
  event.se_on = 1;
  for (unsigned short event_type : event_types) {
    event.se_type = event_type;
    if (usrsctp_setsockopt(mMasterSocket, IPPROTO_SCTP, SCTP_EVENT, &event, sizeof(event)) < 0) {
      LOG(("*** failed setsockopt SCTP_EVENT errno %d", errno));
      goto error_cleanup;
    }
  }

  // Update number of streams
  mStreams.AppendElements(aNumStreams);
  for (uint32_t i = 0; i < aNumStreams; ++i) {
    mStreams[i] = nullptr;
  }
  memset(&initmsg, 0, sizeof(initmsg));
  len = sizeof(initmsg);
  if (usrsctp_getsockopt(mMasterSocket, IPPROTO_SCTP, SCTP_INITMSG, &initmsg, &len) < 0) {
    LOG(("*** failed getsockopt SCTP_INITMSG"));
    goto error_cleanup;
  }
  LOG(("Setting number of SCTP streams to %u, was %u/%u", aNumStreams,
       initmsg.sinit_num_ostreams, initmsg.sinit_max_instreams));
  initmsg.sinit_num_ostreams  = aNumStreams;
  initmsg.sinit_max_instreams = MAX_NUM_STREAMS;
  if (usrsctp_setsockopt(mMasterSocket, IPPROTO_SCTP, SCTP_INITMSG, &initmsg,
                         (socklen_t)sizeof(initmsg)) < 0) {
    LOG(("*** failed setsockopt SCTP_INITMSG, errno %d", errno));
    goto error_cleanup;
  }

  mSocket = nullptr;
  if (aUsingDtls) {
    mUsingDtls = true;
    usrsctp_register_address(static_cast<void *>(this));
    LOG(("Registered %p within the SCTP stack.", static_cast<void *>(this)));
  } else {
    mUsingDtls = false;
  }
  return true;

error_cleanup:
  usrsctp_close(mMasterSocket);
  mMasterSocket = nullptr;
  mUsingDtls = false;
  return false;
}

#ifdef MOZ_PEERCONNECTION
void
DataChannelConnection::SetEvenOdd()
{
  ASSERT_WEBRTC(IsSTSThread());

  TransportLayerDtls *dtls = static_cast<TransportLayerDtls *>(
      mTransportFlow->GetLayer(TransportLayerDtls::ID()));
  MOZ_ASSERT(dtls);  // DTLS is mandatory
  mAllocateEven = (dtls->role() == TransportLayerDtls::CLIENT);
}

bool
DataChannelConnection::ConnectViaTransportFlow(TransportFlow *aFlow, uint16_t localport, uint16_t remoteport)
{
  LOG(("Connect DTLS local %u, remote %u", localport, remoteport));

  NS_PRECONDITION(mMasterSocket, "SCTP wasn't initialized before ConnectViaTransportFlow!");
  NS_ENSURE_TRUE(aFlow, false);

  mTransportFlow = aFlow;
  mLocalPort = localport;
  mRemotePort = remoteport;
  mState = CONNECTING;

  RUN_ON_THREAD(mSTS, WrapRunnable(RefPtr<DataChannelConnection>(this),
                                   &DataChannelConnection::SetSignals),
                NS_DISPATCH_NORMAL);
  return true;
}

void
DataChannelConnection::SetSignals()
{
  ASSERT_WEBRTC(IsSTSThread());
  ASSERT_WEBRTC(mTransportFlow);
  LOG(("Setting transport signals, state: %d", mTransportFlow->state()));
  mTransportFlow->SignalPacketReceived.connect(this, &DataChannelConnection::SctpDtlsInput);
  // SignalStateChange() doesn't call you with the initial state
  mTransportFlow->SignalStateChange.connect(this, &DataChannelConnection::CompleteConnect);
  CompleteConnect(mTransportFlow, mTransportFlow->state());
}

void
DataChannelConnection::CompleteConnect(TransportFlow *flow, TransportLayer::State state)
{
  LOG(("Data transport state: %d", state));
  MutexAutoLock lock(mLock);
  ASSERT_WEBRTC(IsSTSThread());
  // We should abort connection on TS_ERROR.
  // Note however that the association will also fail (perhaps with a delay) and
  // notify us in that way
  if (state != TransportLayer::TS_OPEN || !mMasterSocket)
    return;

  struct sockaddr_conn addr;
  memset(&addr, 0, sizeof(addr));
  addr.sconn_family = AF_CONN;
#if defined(__Userspace_os_Darwin)
  addr.sconn_len = sizeof(addr);
#endif
  addr.sconn_port = htons(mLocalPort);
  addr.sconn_addr = static_cast<void *>(this);

  LOG(("Calling usrsctp_bind"));
  int r = usrsctp_bind(mMasterSocket, reinterpret_cast<struct sockaddr *>(&addr),
                       sizeof(addr));
  if (r < 0) {
    LOG(("usrsctp_bind failed: %d", r));
  } else {
    // This is the remote addr
    addr.sconn_port = htons(mRemotePort);
    LOG(("Calling usrsctp_connect"));
    r = usrsctp_connect(mMasterSocket, reinterpret_cast<struct sockaddr *>(&addr),
                        sizeof(addr));
    if (r >= 0 || errno == EINPROGRESS) {
      struct sctp_paddrparams paddrparams;
      socklen_t opt_len;

      memset(&paddrparams, 0, sizeof(struct sctp_paddrparams));
      memcpy(&paddrparams.spp_address, &addr, sizeof(struct sockaddr_conn));
      opt_len = (socklen_t)sizeof(struct sctp_paddrparams);
      r = usrsctp_getsockopt(mMasterSocket, IPPROTO_SCTP, SCTP_PEER_ADDR_PARAMS,
                             &paddrparams, &opt_len);
      if (r < 0) {
        LOG(("usrsctp_getsockopt failed: %d", r));
      } else {
        // draft-ietf-rtcweb-data-channel-13 section 5: max initial MTU IPV4 1200, IPV6 1280
        paddrparams.spp_pathmtu = 1200; // safe for either
        paddrparams.spp_flags &= ~SPP_PMTUD_ENABLE;
        paddrparams.spp_flags |= SPP_PMTUD_DISABLE;
        opt_len = (socklen_t)sizeof(struct sctp_paddrparams);
        r = usrsctp_setsockopt(mMasterSocket, IPPROTO_SCTP, SCTP_PEER_ADDR_PARAMS,
                               &paddrparams, opt_len);
        if (r < 0) {
          LOG(("usrsctp_getsockopt failed: %d", r));
        } else {
          LOG(("usrsctp: PMTUD disabled, MTU set to %u", paddrparams.spp_pathmtu));
        }
      }
    }
    if (r < 0) {
      if (errno == EINPROGRESS) {
        // non-blocking
        return;
      } else {
        LOG(("usrsctp_connect failed: %d", errno));
        mState = CLOSED;
      }
    } else {
      // We set Even/Odd and fire ON_CONNECTION via SCTP_COMM_UP when we get that
      // This also avoids issues with calling TransportFlow stuff on Mainthread
      return;
    }
  }
  // Note: currently this doesn't actually notify the application
  NS_DispatchToMainThread(do_AddRef(new DataChannelOnMessageAvailable(
                                      DataChannelOnMessageAvailable::ON_CONNECTION,
                                      this)));
  return;
}

// Process any pending Opens
void
DataChannelConnection::ProcessQueuedOpens()
{
  // The nsDeque holds channels with an AddRef applied.  Another reference
  // (may) be held by the DOMDataChannel, unless it's been GC'd.  No other
  // references should exist.

  // Can't copy nsDeque's.  Move into temp array since any that fail will
  // go back to mPending
  nsDeque temp;
  DataChannel *temp_channel; // really already_AddRefed<>
  while (nullptr != (temp_channel = static_cast<DataChannel *>(mPending.PopFront()))) {
    temp.Push(static_cast<void *>(temp_channel));
  }

  RefPtr<DataChannel> channel;
  // All these entries have an AddRef(); make that explicit now via the dont_AddRef()
  while (nullptr != (channel = dont_AddRef(static_cast<DataChannel *>(temp.PopFront())))) {
    if (channel->mFlags & DATA_CHANNEL_FLAGS_FINISH_OPEN) {
      LOG(("Processing queued open for %p (%u)", channel.get(), channel->mStream));
      channel->mFlags &= ~DATA_CHANNEL_FLAGS_FINISH_OPEN;
      // OpenFinish returns a reference itself, so we need to take it can Release it
      channel = OpenFinish(channel.forget()); // may reset the flag and re-push
    } else {
      NS_ASSERTION(false, "How did a DataChannel get queued without the FINISH_OPEN flag?");
    }
  }

}
void
DataChannelConnection::SctpDtlsInput(TransportFlow *flow,
                                     const unsigned char *data, size_t len)
{
  if (MOZ_LOG_TEST(gSCTPLog, LogLevel::Debug)) {
    char *buf;

    if ((buf = usrsctp_dumppacket((void *)data, len, SCTP_DUMP_INBOUND)) != nullptr) {
      PR_LogPrint("%s", buf);
      usrsctp_freedumpbuffer(buf);
    }
  }
  // Pass the data to SCTP
  MutexAutoLock lock(mLock);
  usrsctp_conninput(static_cast<void *>(this), data, len, 0);
}

int
DataChannelConnection::SendPacket(unsigned char data[], size_t len, bool release)
{
  //LOG(("%p: SCTP/DTLS sent %ld bytes", this, len));
  int res = 0;
  if (mTransportFlow) {
    res = mTransportFlow->SendPacket(data, len) < 0 ? 1 : 0;
  }
  if (release)
    delete [] data;
  return res;
}

/* static */
int
DataChannelConnection::SctpDtlsOutput(void *addr, void *buffer, size_t length,
                                      uint8_t tos, uint8_t set_df)
{
  DataChannelConnection *peer = static_cast<DataChannelConnection *>(addr);
  int res;

  if (MOZ_LOG_TEST(gSCTPLog, LogLevel::Debug)) {
    char *buf;

    if ((buf = usrsctp_dumppacket(buffer, length, SCTP_DUMP_OUTBOUND)) != nullptr) {
      PR_LogPrint("%s", buf);
      usrsctp_freedumpbuffer(buf);
    }
  }
  // We're async proxying even if on the STSThread because this is called
  // with internal SCTP locks held in some cases (such as in usrsctp_connect()).
  // SCTP has an option for Apple, on IP connections only, to release at least
  // one of the locks before calling a packet output routine; with changes to
  // the underlying SCTP stack this might remove the need to use an async proxy.
  if ((false /*peer->IsSTSThread()*/)) {
    res = peer->SendPacket(static_cast<unsigned char *>(buffer), length, false);
  } else {
    auto *data = new unsigned char[length];
    memcpy(data, buffer, length);
    // Commented out since we have to Dispatch SendPacket to avoid deadlock"
    // res = -1;

    // XXX It might be worthwhile to add an assertion against the thread
    // somehow getting into the DataChannel/SCTP code again, as
    // DISPATCH_SYNC is not fully blocking.  This may be tricky, as it
    // needs to be a per-thread check, not a global.
    peer->mSTS->Dispatch(WrapRunnable(
                           RefPtr<DataChannelConnection>(peer),
                           &DataChannelConnection::SendPacket, data, length, true),
                                   NS_DISPATCH_NORMAL);
    res = 0; // cheat!  Packets can always be dropped later anyways
  }
  return res;
}
#endif

#ifdef ALLOW_DIRECT_SCTP_LISTEN_CONNECT
// listen for incoming associations
// Blocks! - Don't call this from main thread!

#error This code will not work as-is since SetEvenOdd() runs on Mainthread

bool
DataChannelConnection::Listen(unsigned short port)
{
  struct sockaddr_in addr;
  socklen_t addr_len;

  NS_WARNING_ASSERTION(!NS_IsMainThread(),
                       "Blocks, do not call from main thread!!!");

  /* Acting as the 'server' */
  memset((void *)&addr, 0, sizeof(addr));
#ifdef HAVE_SIN_LEN
  addr.sin_len = sizeof(struct sockaddr_in);
#endif
  addr.sin_family = AF_INET;
  addr.sin_port = htons(port);
  addr.sin_addr.s_addr = htonl(INADDR_ANY);
  LOG(("Waiting for connections on port %u", ntohs(addr.sin_port)));
  mState = CONNECTING;
  if (usrsctp_bind(mMasterSocket, reinterpret_cast<struct sockaddr *>(&addr), sizeof(struct sockaddr_in)) < 0) {
    LOG(("***Failed userspace_bind"));
    return false;
  }
  if (usrsctp_listen(mMasterSocket, 1) < 0) {
    LOG(("***Failed userspace_listen"));
    return false;
  }

  LOG(("Accepting connection"));
  addr_len = 0;
  if ((mSocket = usrsctp_accept(mMasterSocket, nullptr, &addr_len)) == nullptr) {
    LOG(("***Failed accept"));
    return false;
  }
  mState = OPEN;

  struct linger l;
  l.l_onoff = 1;
  l.l_linger = 0;
  if (usrsctp_setsockopt(mSocket, SOL_SOCKET, SO_LINGER,
                         (const void *)&l, (socklen_t)sizeof(struct linger)) < 0) {
    LOG(("Couldn't set SO_LINGER on SCTP socket"));
  }

  SetEvenOdd();

  // Notify Connection open
  // XXX We need to make sure connection sticks around until the message is delivered
  LOG(("%s: sending ON_CONNECTION for %p", __FUNCTION__, this));
  NS_DispatchToMainThread(do_AddRef(new DataChannelOnMessageAvailable(
                            DataChannelOnMessageAvailable::ON_CONNECTION,
                            this, (DataChannel *) nullptr)));
  return true;
}

// Blocks! - Don't call this from main thread!
bool
DataChannelConnection::Connect(const char *addr, unsigned short port)
{
  struct sockaddr_in addr4;
  struct sockaddr_in6 addr6;

  NS_WARNING_ASSERTION(!NS_IsMainThread(),
                       "Blocks, do not call from main thread!!!");

  /* Acting as the connector */
  LOG(("Connecting to %s, port %u", addr, port));
  memset((void *)&addr4, 0, sizeof(struct sockaddr_in));
  memset((void *)&addr6, 0, sizeof(struct sockaddr_in6));
#ifdef HAVE_SIN_LEN
  addr4.sin_len = sizeof(struct sockaddr_in);
#endif
#ifdef HAVE_SIN6_LEN
  addr6.sin6_len = sizeof(struct sockaddr_in6);
#endif
  addr4.sin_family = AF_INET;
  addr6.sin6_family = AF_INET6;
  addr4.sin_port = htons(port);
  addr6.sin6_port = htons(port);
  mState = CONNECTING;

#if !defined(__Userspace_os_Windows)
  if (inet_pton(AF_INET6, addr, &addr6.sin6_addr) == 1) {
    if (usrsctp_connect(mMasterSocket, reinterpret_cast<struct sockaddr *>(&addr6), sizeof(struct sockaddr_in6)) < 0) {
      LOG(("*** Failed userspace_connect"));
      return false;
    }
  } else if (inet_pton(AF_INET, addr, &addr4.sin_addr) == 1) {
    if (usrsctp_connect(mMasterSocket, reinterpret_cast<struct sockaddr *>(&addr4), sizeof(struct sockaddr_in)) < 0) {
      LOG(("*** Failed userspace_connect"));
      return false;
    }
  } else {
    LOG(("*** Illegal destination address."));
  }
#else
  {
    struct sockaddr_storage ss;
    int sslen = sizeof(ss);

    if (!WSAStringToAddressA(const_cast<char *>(addr), AF_INET6, nullptr, (struct sockaddr*)&ss, &sslen)) {
      addr6.sin6_addr = (reinterpret_cast<struct sockaddr_in6 *>(&ss))->sin6_addr;
      if (usrsctp_connect(mMasterSocket, reinterpret_cast<struct sockaddr *>(&addr6), sizeof(struct sockaddr_in6)) < 0) {
        LOG(("*** Failed userspace_connect"));
        return false;
      }
    } else if (!WSAStringToAddressA(const_cast<char *>(addr), AF_INET, nullptr, (struct sockaddr*)&ss, &sslen)) {
      addr4.sin_addr = (reinterpret_cast<struct sockaddr_in *>(&ss))->sin_addr;
      if (usrsctp_connect(mMasterSocket, reinterpret_cast<struct sockaddr *>(&addr4), sizeof(struct sockaddr_in)) < 0) {
        LOG(("*** Failed userspace_connect"));
        return false;
      }
    } else {
      LOG(("*** Illegal destination address."));
    }
  }
#endif

  mSocket = mMasterSocket;

  LOG(("connect() succeeded!  Entering connected mode"));
  mState = OPEN;

  SetEvenOdd();

  // Notify Connection open
  // XXX We need to make sure connection sticks around until the message is delivered
  LOG(("%s: sending ON_CONNECTION for %p", __FUNCTION__, this));
  NS_DispatchToMainThread(do_AddRef(new DataChannelOnMessageAvailable(
                            DataChannelOnMessageAvailable::ON_CONNECTION,
                            this, (DataChannel *) nullptr)));
  return true;
}
#endif

DataChannel *
DataChannelConnection::FindChannelByStream(uint16_t stream)
{
  return mStreams.SafeElementAt(stream);
}

uint16_t
DataChannelConnection::FindFreeStream()
{
  uint32_t i, j, limit;

  limit = mStreams.Length();
  if (limit > MAX_NUM_STREAMS)
    limit = MAX_NUM_STREAMS;

  for (i = (mAllocateEven ? 0 : 1); i < limit; i += 2) {
    if (!mStreams[i]) {
      // Verify it's not still in the process of closing
      for (j = 0; j < mStreamsResetting.Length(); ++j) {
        if (mStreamsResetting[j] == i) {
          break;
        }
      }
      if (j == mStreamsResetting.Length())
        break;
    }
  }
  if (i >= limit) {
    return INVALID_STREAM;
  }
  return i;
}

bool
DataChannelConnection::RequestMoreStreams(int32_t aNeeded)
{
  struct sctp_status status;
  struct sctp_add_streams sas;
  uint32_t outStreamsNeeded;
  socklen_t len;

  if (aNeeded + mStreams.Length() > MAX_NUM_STREAMS) {
    aNeeded = MAX_NUM_STREAMS - mStreams.Length();
  }
  if (aNeeded <= 0) {
    return false;
  }

  len = (socklen_t)sizeof(struct sctp_status);
  if (usrsctp_getsockopt(mMasterSocket, IPPROTO_SCTP, SCTP_STATUS, &status, &len) < 0) {
    LOG(("***failed: getsockopt SCTP_STATUS"));
    return false;
  }
  outStreamsNeeded = aNeeded; // number to add

  // Note: if multiple channel opens happen when we don't have enough space,
  // we'll call RequestMoreStreams() multiple times
  memset(&sas, 0, sizeof(sas));
  sas.sas_instrms = 0;
  sas.sas_outstrms = (uint16_t)outStreamsNeeded; /* XXX error handling */
  // Doesn't block, we get an event when it succeeds or fails
  if (usrsctp_setsockopt(mMasterSocket, IPPROTO_SCTP, SCTP_ADD_STREAMS, &sas,
                         (socklen_t) sizeof(struct sctp_add_streams)) < 0) {
    if (errno == EALREADY) {
      LOG(("Already have %u output streams", outStreamsNeeded));
      return true;
    }

    LOG(("***failed: setsockopt ADD errno=%d", errno));
    return false;
  }
  LOG(("Requested %u more streams", outStreamsNeeded));
  // We add to mStreams when we get a SCTP_STREAM_CHANGE_EVENT and the
  // values are larger than mStreams.Length()
  return true;
}

int32_t
DataChannelConnection::SendControlMessage(void *msg, uint32_t len, uint16_t stream)
{
  struct sctp_sndinfo sndinfo;

  // Note: Main-thread IO, but doesn't block
  memset(&sndinfo, 0, sizeof(struct sctp_sndinfo));
  sndinfo.snd_sid = stream;
  sndinfo.snd_ppid = htonl(DATA_CHANNEL_PPID_CONTROL);
  if (usrsctp_sendv(mSocket, msg, len, nullptr, 0,
                    &sndinfo, (socklen_t)sizeof(struct sctp_sndinfo),
                    SCTP_SENDV_SNDINFO, 0) < 0) {
    //LOG(("***failed: sctp_sendv")); don't log because errno is a return!
    return (0);
  }
  return (1);
}

int32_t
DataChannelConnection::SendOpenAckMessage(uint16_t stream)
{
  struct rtcweb_datachannel_ack ack;

  memset(&ack, 0, sizeof(struct rtcweb_datachannel_ack));
  ack.msg_type = DATA_CHANNEL_ACK;

  return SendControlMessage(&ack, sizeof(ack), stream);
}

int32_t
DataChannelConnection::SendOpenRequestMessage(const nsACString& label,
                                              const nsACString& protocol,
                                              uint16_t stream, bool unordered,
                                              uint16_t prPolicy, uint32_t prValue)
{
  const int label_len = label.Length(); // not including nul
  const int proto_len = protocol.Length(); // not including nul
  // careful - request struct include one char for the label
  const int req_size = sizeof(struct rtcweb_datachannel_open_request) - 1 +
                        label_len + proto_len;
  struct rtcweb_datachannel_open_request *req =
    (struct rtcweb_datachannel_open_request*) moz_xmalloc(req_size);

  memset(req, 0, req_size);
  req->msg_type = DATA_CHANNEL_OPEN_REQUEST;
  switch (prPolicy) {
  case SCTP_PR_SCTP_NONE:
    req->channel_type = DATA_CHANNEL_RELIABLE;
    break;
  case SCTP_PR_SCTP_TTL:
    req->channel_type = DATA_CHANNEL_PARTIAL_RELIABLE_TIMED;
    break;
  case SCTP_PR_SCTP_RTX:
    req->channel_type = DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT;
    break;
  default:
    // FIX! need to set errno!  Or make all these SendXxxx() funcs return 0 or errno!
    free(req);
    return (0);
  }
  if (unordered) {
    // Per the current types, all differ by 0x80 between ordered and unordered
    req->channel_type |= 0x80; // NOTE: be careful if new types are added in the future
  }

  req->reliability_param = htonl(prValue);
  req->priority = htons(0); /* XXX: add support */
  req->label_length = htons(label_len);
  req->protocol_length = htons(proto_len);
  memcpy(&req->label[0], PromiseFlatCString(label).get(), label_len);
  memcpy(&req->label[label_len], PromiseFlatCString(protocol).get(), proto_len);

  int32_t result = SendControlMessage(req, req_size, stream);

  free(req);
  return result;
}

// XXX This should use a separate thread (outbound queue) which should
// select() to know when to *try* to send data to the socket again.
// Alternatively, it can use a timeout, but that's guaranteed to be wrong
// (just not sure in what direction).  We could re-implement NSPR's
// PR_POLL_WRITE/etc handling... with a lot of work.

// Better yet, use the SCTP stack's notifications on buffer state to avoid
// filling the SCTP's buffers.

// returns if we're still blocked or not
bool
DataChannelConnection::SendDeferredMessages()
{
  uint32_t i;
  RefPtr<DataChannel> channel; // we may null out the refs to this
  bool still_blocked = false;

  // This may block while something is modifying channels, but should not block for IO
  mLock.AssertCurrentThreadOwns();

  // XXX For total fairness, on a still_blocked we'd start next time at the
  // same index.  Sorry, not going to bother for now.
  for (i = 0; i < mStreams.Length(); ++i) {
    channel = mStreams[i];
    if (!channel)
      continue;

    // Only one of these should be set....
    if (channel->mFlags & DATA_CHANNEL_FLAGS_SEND_REQ) {
      if (SendOpenRequestMessage(channel->mLabel, channel->mProtocol,
                                 channel->mStream,
                                 channel->mFlags & DATA_CHANNEL_FLAGS_OUT_OF_ORDER_ALLOWED,
                                 channel->mPrPolicy, channel->mPrValue)) {
        channel->mFlags &= ~DATA_CHANNEL_FLAGS_SEND_REQ;

        channel->mState = OPEN;
        channel->mReady = true;
        LOG(("%s: sending ON_CHANNEL_OPEN for %p", __FUNCTION__, channel.get()));
        NS_DispatchToMainThread(do_AddRef(new DataChannelOnMessageAvailable(
                                  DataChannelOnMessageAvailable::ON_CHANNEL_OPEN, this,
                                  channel)));
      } else {
        if (errno == EAGAIN || errno == EWOULDBLOCK) {
          still_blocked = true;
        } else {
          // Close the channel, inform the user
          mStreams[channel->mStream] = nullptr;
          channel->mState = CLOSED;
          // Don't need to reset; we didn't open it
          NS_DispatchToMainThread(do_AddRef(new DataChannelOnMessageAvailable(
                                    DataChannelOnMessageAvailable::ON_CHANNEL_CLOSED, this,
                                    channel)));
        }
      }
    }
    if (still_blocked)
      break;

    if (channel->mFlags & DATA_CHANNEL_FLAGS_SEND_ACK) {
      if (SendOpenAckMessage(channel->mStream)) {
        channel->mFlags &= ~DATA_CHANNEL_FLAGS_SEND_ACK;
      } else {
        if (errno == EAGAIN || errno == EWOULDBLOCK) {
          still_blocked = true;
        } else {
          // Close the channel, inform the user
          CloseInt(channel);
          // XXX send error via DataChannelOnMessageAvailable (bug 843625)
        }
      }
    }
    if (still_blocked)
      break;

    if (channel->mFlags & DATA_CHANNEL_FLAGS_SEND_DATA) {
      bool failed_send = false;
      int32_t result;

      if (channel->mState == CLOSED || channel->mState == CLOSING) {
        channel->mBufferedData.Clear();
      }

      uint32_t buffered_amount = channel->GetBufferedAmountLocked();
      uint32_t threshold = channel->GetBufferedAmountLowThreshold();
      bool was_over_threshold = buffered_amount >= threshold;

      while (!channel->mBufferedData.IsEmpty() &&
             !failed_send) {
        struct sctp_sendv_spa *spa = channel->mBufferedData[0]->mSpa;
        const char *data           = channel->mBufferedData[0]->mData;
        size_t len                 = channel->mBufferedData[0]->mLength;

        // SCTP will return EMSGSIZE if the message is bigger than the buffer
        // size (or EAGAIN if there isn't space)
        if ((result = usrsctp_sendv(mSocket, data, len,
                                    nullptr, 0,
                                    (void *)spa, (socklen_t)sizeof(struct sctp_sendv_spa),
                                    SCTP_SENDV_SPA,
                                    0)) < 0) {
          if (errno == EAGAIN || errno == EWOULDBLOCK) {
            // leave queued for resend
            failed_send = true;
            LOG(("queue full again when resending %d bytes (%d)", len, result));
          } else {
            LOG(("error %d re-sending string", errno));
            failed_send = true;
          }
        } else {
          LOG(("Resent buffer of %d bytes (%d)", len, result));
          // In theory this could underflow if >4GB was buffered and re
          // truncated in GetBufferedAmount(), but this won't cause any problems.
          buffered_amount -= channel->mBufferedData[0]->mLength;
          channel->mBufferedData.RemoveElementAt(0);
          // can never fire with default threshold of 0
          if (was_over_threshold && buffered_amount < threshold) {
            LOG(("%s: sending BUFFER_LOW_THRESHOLD for %s/%s: %u", __FUNCTION__,
                 channel->mLabel.get(), channel->mProtocol.get(), channel->mStream));
            NS_DispatchToMainThread(do_AddRef(new DataChannelOnMessageAvailable(
                                                DataChannelOnMessageAvailable::BUFFER_LOW_THRESHOLD,
                                                this, channel)));
            was_over_threshold = false;
          }
          if (buffered_amount == 0) {
            // buffered-to-not-buffered transition; tell the DOM code in case this makes it
            // available for GC
            LOG(("%s: sending NO_LONGER_BUFFERED for %s/%s: %u", __FUNCTION__,
                 channel->mLabel.get(), channel->mProtocol.get(), channel->mStream));
            NS_DispatchToMainThread(do_AddRef(new DataChannelOnMessageAvailable(
                                                DataChannelOnMessageAvailable::NO_LONGER_BUFFERED,
                                                this, channel)));
          }
        }
      }
      if (channel->mBufferedData.IsEmpty())
        channel->mFlags &= ~DATA_CHANNEL_FLAGS_SEND_DATA;
      else
        still_blocked = true;
    }
    if (still_blocked)
      break;
  }

  return still_blocked;
}

void
DataChannelConnection::HandleOpenRequestMessage(const struct rtcweb_datachannel_open_request *req,
                                                size_t length,
                                                uint16_t stream)
{
  RefPtr<DataChannel> channel;
  uint32_t prValue;
  uint16_t prPolicy;
  uint32_t flags;

  mLock.AssertCurrentThreadOwns();

  if (length != (sizeof(*req) - 1) + ntohs(req->label_length) + ntohs(req->protocol_length)) {
    LOG(("%s: Inconsistent length: %u, should be %u", __FUNCTION__, length,
         (sizeof(*req) - 1) + ntohs(req->label_length) + ntohs(req->protocol_length)));
    if (length < (sizeof(*req) - 1) + ntohs(req->label_length) + ntohs(req->protocol_length))
      return;
  }

  LOG(("%s: length %u, sizeof(*req) = %u", __FUNCTION__, length, sizeof(*req)));

  switch (req->channel_type) {
    case DATA_CHANNEL_RELIABLE:
    case DATA_CHANNEL_RELIABLE_UNORDERED:
      prPolicy = SCTP_PR_SCTP_NONE;
      break;
    case DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT:
    case DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT_UNORDERED:
      prPolicy = SCTP_PR_SCTP_RTX;
      break;
    case DATA_CHANNEL_PARTIAL_RELIABLE_TIMED:
    case DATA_CHANNEL_PARTIAL_RELIABLE_TIMED_UNORDERED:
      prPolicy = SCTP_PR_SCTP_TTL;
      break;
    default:
      LOG(("Unknown channel type", req->channel_type));
      /* XXX error handling */
      return;
  }
  prValue = ntohl(req->reliability_param);
  flags = (req->channel_type & 0x80) ? DATA_CHANNEL_FLAGS_OUT_OF_ORDER_ALLOWED : 0;

  if ((channel = FindChannelByStream(stream))) {
    if (!(channel->mFlags & DATA_CHANNEL_FLAGS_EXTERNAL_NEGOTIATED)) {
      LOG(("ERROR: HandleOpenRequestMessage: channel for stream %u is in state %d instead of CLOSED.",
           stream, channel->mState));
     /* XXX: some error handling */
    } else {
      LOG(("Open for externally negotiated channel %u", stream));
      // XXX should also check protocol, maybe label
      if (prPolicy != channel->mPrPolicy ||
          prValue != channel->mPrValue ||
          flags != (channel->mFlags & DATA_CHANNEL_FLAGS_OUT_OF_ORDER_ALLOWED))
      {
        LOG(("WARNING: external negotiation mismatch with OpenRequest:"
             "channel %u, policy %u/%u, value %u/%u, flags %x/%x",
             stream, prPolicy, channel->mPrPolicy,
             prValue, channel->mPrValue, flags, channel->mFlags));
      }
    }
    return;
  }
  if (stream >= mStreams.Length()) {
    LOG(("%s: stream %u out of bounds (%u)", __FUNCTION__, stream, mStreams.Length()));
    return;
  }

  nsCString label(nsDependentCSubstring(&req->label[0], ntohs(req->label_length)));
  nsCString protocol(nsDependentCSubstring(&req->label[ntohs(req->label_length)],
                                           ntohs(req->protocol_length)));

  channel = new DataChannel(this,
                            stream,
                            DataChannel::CONNECTING,
                            label,
                            protocol,
                            prPolicy, prValue,
                            flags,
                            nullptr, nullptr);
  mStreams[stream] = channel;

  channel->mState = DataChannel::WAITING_TO_OPEN;

  LOG(("%s: sending ON_CHANNEL_CREATED for %s/%s: %u (state %u)", __FUNCTION__,
       channel->mLabel.get(), channel->mProtocol.get(), stream, channel->mState));
  NS_DispatchToMainThread(do_AddRef(new DataChannelOnMessageAvailable(
                            DataChannelOnMessageAvailable::ON_CHANNEL_CREATED,
                            this, channel)));

  LOG(("%s: deferring sending ON_CHANNEL_OPEN for %p", __FUNCTION__, channel.get()));

  if (!SendOpenAckMessage(stream)) {
    // XXX Only on EAGAIN!?  And if not, then close the channel??
    channel->mFlags |= DATA_CHANNEL_FLAGS_SEND_ACK;
    // Note: we're locked, so there's no danger of a race with the
    // buffer-threshold callback
  }

  // Now process any queued data messages for the channel (which will
  // themselves likely get queued until we leave WAITING_TO_OPEN, plus any
  // more that come in before that happens)
  DeliverQueuedData(stream);
}

// NOTE: the updated spec from the IETF says we should set in-order until we receive an ACK.
// That would make this code moot.  Keep it for now for backwards compatibility.
void
DataChannelConnection::DeliverQueuedData(uint16_t stream)
{
  mLock.AssertCurrentThreadOwns();

  uint32_t i = 0;
  while (i < mQueuedData.Length()) {
    // Careful! we may modify the array length from within the loop!
    if (mQueuedData[i]->mStream == stream) {
      LOG(("Delivering queued data for stream %u, length %u",
           stream, (unsigned int) mQueuedData[i]->mLength));
      // Deliver the queued data
      HandleDataMessage(mQueuedData[i]->mPpid,
                        mQueuedData[i]->mData, mQueuedData[i]->mLength,
                        mQueuedData[i]->mStream);
      mQueuedData.RemoveElementAt(i);
      continue; // don't bump index since we removed the element
    }
    i++;
  }
}

void
DataChannelConnection::HandleOpenAckMessage(const struct rtcweb_datachannel_ack *ack,
                                            size_t length, uint16_t stream)
{
  DataChannel *channel;

  mLock.AssertCurrentThreadOwns();

  channel = FindChannelByStream(stream);
  NS_ENSURE_TRUE_VOID(channel);

  LOG(("OpenAck received for stream %u, waiting=%d", stream,
       (channel->mFlags & DATA_CHANNEL_FLAGS_WAITING_ACK) ? 1 : 0));

  channel->mFlags &= ~DATA_CHANNEL_FLAGS_WAITING_ACK;
}

void
DataChannelConnection::HandleUnknownMessage(uint32_t ppid, size_t length, uint16_t stream)
{
  /* XXX: Send an error message? */
  LOG(("unknown DataChannel message received: %u, len %ld on stream %lu", ppid, length, stream));
  // XXX Log to JS error console if possible
}

void
DataChannelConnection::HandleDataMessage(uint32_t ppid,
                                         const void *data, size_t length,
                                         uint16_t stream)
{
  DataChannel *channel;
  const char *buffer = (const char *) data;

  mLock.AssertCurrentThreadOwns();

  channel = FindChannelByStream(stream);

  // XXX A closed channel may trip this... check
  // NOTE: the updated spec from the IETF says we should set in-order until we receive an ACK.
  // That would make this code moot.  Keep it for now for backwards compatibility.
  if (!channel) {
    // In the updated 0-RTT open case, the sender can send data immediately
    // after Open, and doesn't set the in-order bit (since we don't have a
    // response or ack).  Also, with external negotiation, data can come in
    // before we're told about the external negotiation.  We need to buffer
    // data until either a) Open comes in, if the ordering get messed up,
    // or b) the app tells us this channel was externally negotiated.  When
    // these occur, we deliver the data.

    // Since this is rare and non-performance, keep a single list of queued
    // data messages to deliver once the channel opens.
    LOG(("Queuing data for stream %u, length %u", stream, length));
    // Copies data
    mQueuedData.AppendElement(new QueuedDataMessage(stream, ppid, data, length));
    return;
  }

  // XXX should this be a simple if, no warnings/debugbreaks?
  NS_ENSURE_TRUE_VOID(channel->mState != CLOSED);

  {
    nsAutoCString recvData(buffer, length); // copies (<64) or allocates
    bool is_binary = true;

    if (ppid == DATA_CHANNEL_PPID_DOMSTRING ||
        ppid == DATA_CHANNEL_PPID_DOMSTRING_LAST) {
      is_binary = false;
    }
    if (is_binary != channel->mIsRecvBinary && !channel->mRecvBuffer.IsEmpty()) {
      NS_WARNING("DataChannel message aborted by fragment type change!");
      channel->mRecvBuffer.Truncate(0);
    }
    channel->mIsRecvBinary = is_binary;

    switch (ppid) {
      case DATA_CHANNEL_PPID_DOMSTRING:
      case DATA_CHANNEL_PPID_BINARY:
        channel->mRecvBuffer += recvData;
        LOG(("DataChannel: Partial %s message of length %lu (total %u) on channel id %u",
             is_binary ? "binary" : "string", length, channel->mRecvBuffer.Length(),
             channel->mStream));
        return; // Not ready to notify application

      case DATA_CHANNEL_PPID_DOMSTRING_LAST:
        LOG(("DataChannel: String message received of length %lu on channel %u",
             length, channel->mStream));
        if (!channel->mRecvBuffer.IsEmpty()) {
          channel->mRecvBuffer += recvData;
          LOG(("%s: sending ON_DATA (string fragmented) for %p", __FUNCTION__, channel));
          channel->SendOrQueue(new DataChannelOnMessageAvailable(
                                 DataChannelOnMessageAvailable::ON_DATA, this,
                                 channel, channel->mRecvBuffer, -1));
          channel->mRecvBuffer.Truncate(0);
          return;
        }
        // else send using recvData normally
        length = -1; // Flag for DOMString

        // WebSockets checks IsUTF8() here; we can try to deliver it
        break;

      case DATA_CHANNEL_PPID_BINARY_LAST:
        LOG(("DataChannel: Received binary message of length %lu on channel id %u",
             length, channel->mStream));
        if (!channel->mRecvBuffer.IsEmpty()) {
          channel->mRecvBuffer += recvData;
          LOG(("%s: sending ON_DATA (binary fragmented) for %p", __FUNCTION__, channel));
          channel->SendOrQueue(new DataChannelOnMessageAvailable(
                                 DataChannelOnMessageAvailable::ON_DATA, this,
                                 channel, channel->mRecvBuffer,
                                 channel->mRecvBuffer.Length()));
          channel->mRecvBuffer.Truncate(0);
          return;
        }
        // else send using recvData normally
        break;

      default:
        NS_ERROR("Unknown data PPID");
        return;
    }
    /* Notify onmessage */
    LOG(("%s: sending ON_DATA for %p", __FUNCTION__, channel));
    channel->SendOrQueue(new DataChannelOnMessageAvailable(
                           DataChannelOnMessageAvailable::ON_DATA, this,
                           channel, recvData, length));
  }
}

// Called with mLock locked!
void
DataChannelConnection::HandleMessage(const void *buffer, size_t length, uint32_t ppid, uint16_t stream)
{
  const struct rtcweb_datachannel_open_request *req;
  const struct rtcweb_datachannel_ack *ack;

  mLock.AssertCurrentThreadOwns();

  switch (ppid) {
    case DATA_CHANNEL_PPID_CONTROL:
      req = static_cast<const struct rtcweb_datachannel_open_request *>(buffer);

      NS_ENSURE_TRUE_VOID(length >= sizeof(*ack)); // smallest message
      switch (req->msg_type) {
        case DATA_CHANNEL_OPEN_REQUEST:
          // structure includes a possibly-unused char label[1] (in a packed structure)
          NS_ENSURE_TRUE_VOID(length >= sizeof(*req) - 1);

          HandleOpenRequestMessage(req, length, stream);
          break;
        case DATA_CHANNEL_ACK:
          // >= sizeof(*ack) checked above

          ack = static_cast<const struct rtcweb_datachannel_ack *>(buffer);
          HandleOpenAckMessage(ack, length, stream);
          break;
        default:
          HandleUnknownMessage(ppid, length, stream);
          break;
      }
      break;
    case DATA_CHANNEL_PPID_DOMSTRING:
    case DATA_CHANNEL_PPID_DOMSTRING_LAST:
    case DATA_CHANNEL_PPID_BINARY:
    case DATA_CHANNEL_PPID_BINARY_LAST:
      HandleDataMessage(ppid, buffer, length, stream);
      break;
    default:
      LOG(("Message of length %lu, PPID %u on stream %u received.",
           length, ppid, stream));
      break;
  }
}

void
DataChannelConnection::HandleAssociationChangeEvent(const struct sctp_assoc_change *sac)
{
  uint32_t i, n;

  switch (sac->sac_state) {
  case SCTP_COMM_UP:
    LOG(("Association change: SCTP_COMM_UP"));
    if (mState == CONNECTING) {
      mSocket = mMasterSocket;
      mState = OPEN;

      SetEvenOdd();

      NS_DispatchToMainThread(do_AddRef(new DataChannelOnMessageAvailable(
                                DataChannelOnMessageAvailable::ON_CONNECTION,
                                this)));
      LOG(("DTLS connect() succeeded!  Entering connected mode"));

      // Open any streams pending...
      ProcessQueuedOpens();

    } else if (mState == OPEN) {
      LOG(("DataConnection Already OPEN"));
    } else {
      LOG(("Unexpected state: %d", mState));
    }
    break;
  case SCTP_COMM_LOST:
    LOG(("Association change: SCTP_COMM_LOST"));
    // This association is toast, so also close all the channels -- from mainthread!
    NS_DispatchToMainThread(do_AddRef(new DataChannelOnMessageAvailable(
                              DataChannelOnMessageAvailable::ON_DISCONNECTED,
                              this)));
    break;
  case SCTP_RESTART:
    LOG(("Association change: SCTP_RESTART"));
    break;
  case SCTP_SHUTDOWN_COMP:
    LOG(("Association change: SCTP_SHUTDOWN_COMP"));
    NS_DispatchToMainThread(do_AddRef(new DataChannelOnMessageAvailable(
                              DataChannelOnMessageAvailable::ON_DISCONNECTED,
                              this)));
    break;
  case SCTP_CANT_STR_ASSOC:
    LOG(("Association change: SCTP_CANT_STR_ASSOC"));
    break;
  default:
    LOG(("Association change: UNKNOWN"));
    break;
  }
  LOG(("Association change: streams (in/out) = (%u/%u)",
       sac->sac_inbound_streams, sac->sac_outbound_streams));

  NS_ENSURE_TRUE_VOID(sac);
  n = sac->sac_length - sizeof(*sac);
  if (((sac->sac_state == SCTP_COMM_UP) ||
        (sac->sac_state == SCTP_RESTART)) && (n > 0)) {
    for (i = 0; i < n; ++i) {
      switch (sac->sac_info[i]) {
      case SCTP_ASSOC_SUPPORTS_PR:
        LOG(("Supports: PR"));
        break;
      case SCTP_ASSOC_SUPPORTS_AUTH:
        LOG(("Supports: AUTH"));
        break;
      case SCTP_ASSOC_SUPPORTS_ASCONF:
        LOG(("Supports: ASCONF"));
        break;
      case SCTP_ASSOC_SUPPORTS_MULTIBUF:
        LOG(("Supports: MULTIBUF"));
        break;
      case SCTP_ASSOC_SUPPORTS_RE_CONFIG:
        LOG(("Supports: RE-CONFIG"));
        break;
      default:
        LOG(("Supports: UNKNOWN(0x%02x)", sac->sac_info[i]));
        break;
      }
    }
  } else if (((sac->sac_state == SCTP_COMM_LOST) ||
              (sac->sac_state == SCTP_CANT_STR_ASSOC)) && (n > 0)) {
    LOG(("Association: ABORT ="));
    for (i = 0; i < n; ++i) {
      LOG((" 0x%02x", sac->sac_info[i]));
    }
  }
  if ((sac->sac_state == SCTP_CANT_STR_ASSOC) ||
      (sac->sac_state == SCTP_SHUTDOWN_COMP) ||
      (sac->sac_state == SCTP_COMM_LOST)) {
    return;
  }
}

void
DataChannelConnection::HandlePeerAddressChangeEvent(const struct sctp_paddr_change *spc)
{
  const char *addr = "";
#if !defined(__Userspace_os_Windows)
  char addr_buf[INET6_ADDRSTRLEN];
  struct sockaddr_in *sin;
  struct sockaddr_in6 *sin6;
#endif

  switch (spc->spc_aaddr.ss_family) {
  case AF_INET:
#if !defined(__Userspace_os_Windows)
    sin = (struct sockaddr_in *)&spc->spc_aaddr;
    addr = inet_ntop(AF_INET, &sin->sin_addr, addr_buf, INET6_ADDRSTRLEN);
#endif
    break;
  case AF_INET6:
#if !defined(__Userspace_os_Windows)
    sin6 = (struct sockaddr_in6 *)&spc->spc_aaddr;
    addr = inet_ntop(AF_INET6, &sin6->sin6_addr, addr_buf, INET6_ADDRSTRLEN);
#endif
    break;
  case AF_CONN:
    addr = "DTLS connection";
    break;
  default:
    break;
  }
  LOG(("Peer address %s is now ", addr));
  switch (spc->spc_state) {
  case SCTP_ADDR_AVAILABLE:
    LOG(("SCTP_ADDR_AVAILABLE"));
    break;
  case SCTP_ADDR_UNREACHABLE:
    LOG(("SCTP_ADDR_UNREACHABLE"));
    break;
  case SCTP_ADDR_REMOVED:
    LOG(("SCTP_ADDR_REMOVED"));
    break;
  case SCTP_ADDR_ADDED:
    LOG(("SCTP_ADDR_ADDED"));
    break;
  case SCTP_ADDR_MADE_PRIM:
    LOG(("SCTP_ADDR_MADE_PRIM"));
    break;
  case SCTP_ADDR_CONFIRMED:
    LOG(("SCTP_ADDR_CONFIRMED"));
    break;
  default:
    LOG(("UNKNOWN"));
    break;
  }
  LOG((" (error = 0x%08x).\n", spc->spc_error));
}

void
DataChannelConnection::HandleRemoteErrorEvent(const struct sctp_remote_error *sre)
{
  size_t i, n;

  n = sre->sre_length - sizeof(struct sctp_remote_error);
  LOG(("Remote Error (error = 0x%04x): ", sre->sre_error));
  for (i = 0; i < n; ++i) {
    LOG((" 0x%02x", sre-> sre_data[i]));
  }
}

void
DataChannelConnection::HandleShutdownEvent(const struct sctp_shutdown_event *sse)
{
  LOG(("Shutdown event."));
  /* XXX: notify all channels. */
  // Attempts to actually send anything will fail
}

void
DataChannelConnection::HandleAdaptationIndication(const struct sctp_adaptation_event *sai)
{
  LOG(("Adaptation indication: %x.", sai-> sai_adaptation_ind));
}

void
DataChannelConnection::HandleSendFailedEvent(const struct sctp_send_failed_event *ssfe)
{
  size_t i, n;

  if (ssfe->ssfe_flags & SCTP_DATA_UNSENT) {
    LOG(("Unsent "));
  }
   if (ssfe->ssfe_flags & SCTP_DATA_SENT) {
    LOG(("Sent "));
  }
  if (ssfe->ssfe_flags & ~(SCTP_DATA_SENT | SCTP_DATA_UNSENT)) {
    LOG(("(flags = %x) ", ssfe->ssfe_flags));
  }
  LOG(("message with PPID = %u, SID = %d, flags: 0x%04x due to error = 0x%08x",
       ntohl(ssfe->ssfe_info.snd_ppid), ssfe->ssfe_info.snd_sid,
       ssfe->ssfe_info.snd_flags, ssfe->ssfe_error));
  n = ssfe->ssfe_length - sizeof(struct sctp_send_failed_event);
  for (i = 0; i < n; ++i) {
    LOG((" 0x%02x", ssfe->ssfe_data[i]));
  }
}

void
DataChannelConnection::ClearResets()
{
  // Clear all pending resets
  if (!mStreamsResetting.IsEmpty()) {
    LOG(("Clearing resets for %d streams", mStreamsResetting.Length()));
  }

  for (uint32_t i = 0; i < mStreamsResetting.Length(); ++i) {
    RefPtr<DataChannel> channel;
    channel = FindChannelByStream(mStreamsResetting[i]);
    if (channel) {
      LOG(("Forgetting channel %u (%p) with pending reset",channel->mStream, channel.get()));
      mStreams[channel->mStream] = nullptr;
    }
  }
  mStreamsResetting.Clear();
}

void
DataChannelConnection::ResetOutgoingStream(uint16_t stream)
{
  uint32_t i;

  mLock.AssertCurrentThreadOwns();
  LOG(("Connection %p: Resetting outgoing stream %u",
       (void *) this, stream));
  // Rarely has more than a couple items and only for a short time
  for (i = 0; i < mStreamsResetting.Length(); ++i) {
    if (mStreamsResetting[i] == stream) {
      return;
    }
  }
  mStreamsResetting.AppendElement(stream);
}

void
DataChannelConnection::SendOutgoingStreamReset()
{
  struct sctp_reset_streams *srs;
  uint32_t i;
  size_t len;

  LOG(("Connection %p: Sending outgoing stream reset for %d streams",
       (void *) this, mStreamsResetting.Length()));
  mLock.AssertCurrentThreadOwns();
  if (mStreamsResetting.IsEmpty()) {
    LOG(("No streams to reset"));
    return;
  }
  len = sizeof(sctp_assoc_t) + (2 + mStreamsResetting.Length()) * sizeof(uint16_t);
  srs = static_cast<struct sctp_reset_streams *> (moz_xmalloc(len)); // infallible malloc
  memset(srs, 0, len);
  srs->srs_flags = SCTP_STREAM_RESET_OUTGOING;
  srs->srs_number_streams = mStreamsResetting.Length();
  for (i = 0; i < mStreamsResetting.Length(); ++i) {
    srs->srs_stream_list[i] = mStreamsResetting[i];
  }
  if (usrsctp_setsockopt(mMasterSocket, IPPROTO_SCTP, SCTP_RESET_STREAMS, srs, (socklen_t)len) < 0) {
    LOG(("***failed: setsockopt RESET, errno %d", errno));
    // if errno == EALREADY, this is normal - we can't send another reset
    // with one pending.
    // When we get an incoming reset (which may be a response to our
    // outstanding one), see if we have any pending outgoing resets and
    // send them
  } else {
    mStreamsResetting.Clear();
  }
  free(srs);
}

void
DataChannelConnection::HandleStreamResetEvent(const struct sctp_stream_reset_event *strrst)
{
  uint32_t n, i;
  RefPtr<DataChannel> channel; // since we may null out the ref to the channel

  if (!(strrst->strreset_flags & SCTP_STREAM_RESET_DENIED) &&
      !(strrst->strreset_flags & SCTP_STREAM_RESET_FAILED)) {
    n = (strrst->strreset_length - sizeof(struct sctp_stream_reset_event)) / sizeof(uint16_t);
    for (i = 0; i < n; ++i) {
      if (strrst->strreset_flags & SCTP_STREAM_RESET_INCOMING_SSN) {
        channel = FindChannelByStream(strrst->strreset_stream_list[i]);
        if (channel) {
          // The other side closed the channel
          // We could be in three states:
          // 1. Normal state (input and output streams (OPEN)
          //    Notify application, send a RESET in response on our
          //    outbound channel.  Go to CLOSED
          // 2. We sent our own reset (CLOSING); either they crossed on the
          //    wire, or this is a response to our Reset.
          //    Go to CLOSED
          // 3. We've sent a open but haven't gotten a response yet (CONNECTING)
          //    I believe this is impossible, as we don't have an input stream yet.

          LOG(("Incoming: Channel %u  closed, state %d",
               channel->mStream, channel->mState));
          ASSERT_WEBRTC(channel->mState == DataChannel::OPEN ||
                        channel->mState == DataChannel::CLOSING ||
                        channel->mState == DataChannel::CONNECTING ||
                        channel->mState == DataChannel::WAITING_TO_OPEN);
          if (channel->mState == DataChannel::OPEN ||
              channel->mState == DataChannel::WAITING_TO_OPEN) {
            // Mark the stream for reset (the reset is sent below)
            ResetOutgoingStream(channel->mStream);
          }
          mStreams[channel->mStream] = nullptr;

          LOG(("Disconnected DataChannel %p from connection %p",
               (void *) channel.get(), (void *) channel->mConnection.get()));
          // This sends ON_CHANNEL_CLOSED to mainthread
          channel->StreamClosedLocked();
        } else {
          LOG(("Can't find incoming channel %d",i));
        }
      }
    }
  }

  // Process any pending resets now:
  if (!mStreamsResetting.IsEmpty()) {
    LOG(("Sending %d pending resets", mStreamsResetting.Length()));
    SendOutgoingStreamReset();
  }
}

void
DataChannelConnection::HandleStreamChangeEvent(const struct sctp_stream_change_event *strchg)
{
  uint16_t stream;
  RefPtr<DataChannel> channel;

  if (strchg->strchange_flags == SCTP_STREAM_CHANGE_DENIED) {
    LOG(("*** Failed increasing number of streams from %u (%u/%u)",
         mStreams.Length(),
         strchg->strchange_instrms,
         strchg->strchange_outstrms));
    // XXX FIX! notify pending opens of failure
    return;
  } else {
    if (strchg->strchange_instrms > mStreams.Length()) {
      LOG(("Other side increased streams from %u to %u",
           mStreams.Length(), strchg->strchange_instrms));
    }
    if (strchg->strchange_outstrms > mStreams.Length() ||
        strchg->strchange_instrms > mStreams.Length()) {
      uint16_t old_len = mStreams.Length();
      uint16_t new_len = std::max(strchg->strchange_outstrms,
                                  strchg->strchange_instrms);
      LOG(("Increasing number of streams from %u to %u - adding %u (in: %u)",
           old_len, new_len, new_len - old_len,
           strchg->strchange_instrms));
      // make sure both are the same length
      mStreams.AppendElements(new_len - old_len);
      LOG(("New length = %d (was %d)", mStreams.Length(), old_len));
      for (size_t i = old_len; i < mStreams.Length(); ++i) {
        mStreams[i] = nullptr;
      }
      // Re-process any channels waiting for streams.
      // Linear search, but we don't increase channels often and
      // the array would only get long in case of an app error normally

      // Make sure we request enough streams if there's a big jump in streams
      // Could make a more complex API for OpenXxxFinish() and avoid this loop
      size_t num_needed = mPending.GetSize();
      LOG(("%d of %d new streams already needed", num_needed,
           new_len - old_len));
      num_needed -= (new_len - old_len); // number we added
      if (num_needed > 0) {
        if (num_needed < 16)
          num_needed = 16;
        LOG(("Not enough new streams, asking for %d more", num_needed));
        RequestMoreStreams(num_needed);
      } else if (strchg->strchange_outstrms < strchg->strchange_instrms) {
        LOG(("Requesting %d output streams to match partner",
             strchg->strchange_instrms - strchg->strchange_outstrms));
        RequestMoreStreams(strchg->strchange_instrms - strchg->strchange_outstrms);
      }

      ProcessQueuedOpens();
    }
    // else probably not a change in # of streams
  }

  for (uint32_t i = 0; i < mStreams.Length(); ++i) {
    channel = mStreams[i];
    if (!channel)
      continue;

    if ((channel->mState == CONNECTING) &&
        (channel->mStream == INVALID_STREAM)) {
      if ((strchg->strchange_flags & SCTP_STREAM_CHANGE_DENIED) ||
          (strchg->strchange_flags & SCTP_STREAM_CHANGE_FAILED)) {
        /* XXX: Signal to the other end. */
        channel->mState = CLOSED;
        NS_DispatchToMainThread(do_AddRef(new DataChannelOnMessageAvailable(
                                  DataChannelOnMessageAvailable::ON_CHANNEL_CLOSED, this,
                                  channel)));
        // maybe fire onError (bug 843625)
      } else {
        stream = FindFreeStream();
        if (stream != INVALID_STREAM) {
          channel->mStream = stream;
          mStreams[stream] = channel;
          channel->mFlags |= DATA_CHANNEL_FLAGS_SEND_REQ;
          // Note: we're locked, so there's no danger of a race with the
          // buffer-threshold callback
        } else {
          /* We will not find more ... */
          break;
        }
      }
    }
  }
}

// Called with mLock locked!
void
DataChannelConnection::HandleNotification(const union sctp_notification *notif, size_t n)
{
  mLock.AssertCurrentThreadOwns();
  if (notif->sn_header.sn_length != (uint32_t)n) {
    return;
  }
  switch (notif->sn_header.sn_type) {
  case SCTP_ASSOC_CHANGE:
    HandleAssociationChangeEvent(&(notif->sn_assoc_change));
    break;
  case SCTP_PEER_ADDR_CHANGE:
    HandlePeerAddressChangeEvent(&(notif->sn_paddr_change));
    break;
  case SCTP_REMOTE_ERROR:
    HandleRemoteErrorEvent(&(notif->sn_remote_error));
    break;
  case SCTP_SHUTDOWN_EVENT:
    HandleShutdownEvent(&(notif->sn_shutdown_event));
    break;
  case SCTP_ADAPTATION_INDICATION:
    HandleAdaptationIndication(&(notif->sn_adaptation_event));
    break;
  case SCTP_PARTIAL_DELIVERY_EVENT:
    LOG(("SCTP_PARTIAL_DELIVERY_EVENT"));
    break;
  case SCTP_AUTHENTICATION_EVENT:
    LOG(("SCTP_AUTHENTICATION_EVENT"));
    break;
  case SCTP_SENDER_DRY_EVENT:
    //LOG(("SCTP_SENDER_DRY_EVENT"));
    break;
  case SCTP_NOTIFICATIONS_STOPPED_EVENT:
    LOG(("SCTP_NOTIFICATIONS_STOPPED_EVENT"));
    break;
  case SCTP_SEND_FAILED_EVENT:
    HandleSendFailedEvent(&(notif->sn_send_failed_event));
    break;
  case SCTP_STREAM_RESET_EVENT:
    HandleStreamResetEvent(&(notif->sn_strreset_event));
    break;
  case SCTP_ASSOC_RESET_EVENT:
    LOG(("SCTP_ASSOC_RESET_EVENT"));
    break;
  case SCTP_STREAM_CHANGE_EVENT:
    HandleStreamChangeEvent(&(notif->sn_strchange_event));
    break;
  default:
    LOG(("unknown SCTP event: %u", (uint32_t)notif->sn_header.sn_type));
    break;
   }
 }

int
DataChannelConnection::ReceiveCallback(struct socket* sock, void *data, size_t datalen,
                                       struct sctp_rcvinfo rcv, int32_t flags)
{
  ASSERT_WEBRTC(!NS_IsMainThread());

  if (!data) {
    usrsctp_close(sock); // SCTP has finished shutting down
  } else {
    bool locked = false;
    if (!IsSTSThread()) {
      mLock.Lock();
      locked = true;
    } else {
      mLock.AssertCurrentThreadOwns();
    }
    if (flags & MSG_NOTIFICATION) {
      HandleNotification(static_cast<union sctp_notification *>(data), datalen);
    } else {
      HandleMessage(data, datalen, ntohl(rcv.rcv_ppid), rcv.rcv_sid);
    }
    if (locked) {
      mLock.Unlock();
    }
  }
  // sctp allocates 'data' with malloc(), and expects the receiver to free
  // it (presumably with free).
  // XXX future optimization: try to deliver messages without an internal
  // alloc/copy, and if so delay the free until later.
  free(data);
  // usrsctp defines the callback as returning an int, but doesn't use it
  return 1;
}

already_AddRefed<DataChannel>
DataChannelConnection::Open(const nsACString& label, const nsACString& protocol,
                            Type type, bool inOrder,
                            uint32_t prValue, DataChannelListener *aListener,
                            nsISupports *aContext, bool aExternalNegotiated,
                            uint16_t aStream)
{
  // aStream == INVALID_STREAM to have the protocol allocate
  uint16_t prPolicy = SCTP_PR_SCTP_NONE;
  uint32_t flags;

  LOG(("DC Open: label %s/%s, type %u, inorder %d, prValue %u, listener %p, context %p, external: %s, stream %u",
       PromiseFlatCString(label).get(), PromiseFlatCString(protocol).get(),
       type, inOrder, prValue, aListener, aContext,
       aExternalNegotiated ? "true" : "false", aStream));
  switch (type) {
    case DATA_CHANNEL_RELIABLE:
      prPolicy = SCTP_PR_SCTP_NONE;
      break;
    case DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT:
      prPolicy = SCTP_PR_SCTP_RTX;
      break;
    case DATA_CHANNEL_PARTIAL_RELIABLE_TIMED:
      prPolicy = SCTP_PR_SCTP_TTL;
      break;
  }
  if ((prPolicy == SCTP_PR_SCTP_NONE) && (prValue != 0)) {
    return nullptr;
  }

  // Don't look past currently-negotiated streams
  if (aStream != INVALID_STREAM && aStream < mStreams.Length() && mStreams[aStream]) {
    LOG(("ERROR: external negotiation of already-open channel %u", aStream));
    // XXX How do we indicate this up to the application?  Probably the
    // caller's job, but we may need to return an error code.
    return nullptr;
  }

  flags = !inOrder ? DATA_CHANNEL_FLAGS_OUT_OF_ORDER_ALLOWED : 0;
  RefPtr<DataChannel> channel(new DataChannel(this,
                                                aStream,
                                                DataChannel::CONNECTING,
                                                label, protocol,
                                                type, prValue,
                                                flags,
                                                aListener, aContext));
  if (aExternalNegotiated) {
    channel->mFlags |= DATA_CHANNEL_FLAGS_EXTERNAL_NEGOTIATED;
  }

  MutexAutoLock lock(mLock); // OpenFinish assumes this
  return OpenFinish(channel.forget());
}

// Separate routine so we can also call it to finish up from pending opens
already_AddRefed<DataChannel>
DataChannelConnection::OpenFinish(already_AddRefed<DataChannel>&& aChannel)
{
  RefPtr<DataChannel> channel(aChannel); // takes the reference passed in
  // Normally 1 reference if called from ::Open(), or 2 if called from
  // ProcessQueuedOpens() unless the DOMDataChannel was gc'd
  uint16_t stream = channel->mStream;
  bool queue = false;

  mLock.AssertCurrentThreadOwns();

  // Cases we care about:
  // Pre-negotiated:
  //    Not Open:
  //      Doesn't fit:
  //         -> change initial ask or renegotiate after open
  //      -> queue open
  //    Open:
  //      Doesn't fit:
  //         -> RequestMoreStreams && queue
  //      Does fit:
  //         -> open
  // Not negotiated:
  //    Not Open:
  //      -> queue open
  //    Open:
  //      -> Try to get a stream
  //      Doesn't fit:
  //         -> RequestMoreStreams && queue
  //      Does fit:
  //         -> open
  // So the Open cases are basically the same
  // Not Open cases are simply queue for non-negotiated, and
  // either change the initial ask or possibly renegotiate after open.

  if (mState == OPEN) {
    if (stream == INVALID_STREAM) {
      stream = FindFreeStream(); // may be INVALID_STREAM if we need more
    }
    if (stream == INVALID_STREAM || stream >= mStreams.Length()) {
      // RequestMoreStreams() limits to MAX_NUM_STREAMS -- allocate extra streams
      // to avoid going back immediately for more if the ask to N, N+1, etc
      int32_t more_needed = (stream == INVALID_STREAM) ? 16 :
                            (stream-((int32_t)mStreams.Length())) + 16;
      if (!RequestMoreStreams(more_needed)) {
        // Something bad happened... we're done
        goto request_error_cleanup;
      }
      queue = true;
    }
  } else {
    // not OPEN
    if (stream != INVALID_STREAM && stream >= mStreams.Length() &&
        mState == CLOSED) {
      // Update number of streams for init message
      struct sctp_initmsg initmsg;
      socklen_t len = sizeof(initmsg);
      int32_t total_needed = stream+16;

      memset(&initmsg, 0, sizeof(initmsg));
      if (usrsctp_getsockopt(mMasterSocket, IPPROTO_SCTP, SCTP_INITMSG, &initmsg, &len) < 0) {
        LOG(("*** failed getsockopt SCTP_INITMSG"));
        goto request_error_cleanup;
      }
      LOG(("Setting number of SCTP streams to %u, was %u/%u", total_needed,
           initmsg.sinit_num_ostreams, initmsg.sinit_max_instreams));
      initmsg.sinit_num_ostreams  = total_needed;
      initmsg.sinit_max_instreams = MAX_NUM_STREAMS;
      if (usrsctp_setsockopt(mMasterSocket, IPPROTO_SCTP, SCTP_INITMSG, &initmsg,
                             (socklen_t)sizeof(initmsg)) < 0) {
        LOG(("*** failed setsockopt SCTP_INITMSG, errno %d", errno));
        goto request_error_cleanup;
      }

      int32_t old_len = mStreams.Length();
      mStreams.AppendElements(total_needed - old_len);
      for (int32_t i = old_len; i < total_needed; ++i) {
        mStreams[i] = nullptr;
      }
    }
    // else if state is CONNECTING, we'll just re-negotiate when OpenFinish
    // is called, if needed
    queue = true;
  }
  if (queue) {
    LOG(("Queuing channel %p (%u) to finish open", channel.get(), stream));
    // Also serves to mark we told the app
    channel->mFlags |= DATA_CHANNEL_FLAGS_FINISH_OPEN;
    // we need a ref for the nsDeQue and one to return
    DataChannel* rawChannel = channel;
    rawChannel->AddRef();
    mPending.Push(rawChannel);
    return channel.forget();
  }

  MOZ_ASSERT(stream != INVALID_STREAM);
  // just allocated (& OPEN), or externally negotiated
  mStreams[stream] = channel; // holds a reference
  channel->mStream = stream;

#ifdef TEST_QUEUED_DATA
  // It's painful to write a test for this...
  channel->mState = OPEN;
  channel->mReady = true;
  SendMsgInternal(channel, "Help me!", 8, DATA_CHANNEL_PPID_DOMSTRING_LAST);
#endif

  if (channel->mFlags & DATA_CHANNEL_FLAGS_OUT_OF_ORDER_ALLOWED) {
    // Don't send unordered until this gets cleared
    channel->mFlags |= DATA_CHANNEL_FLAGS_WAITING_ACK;
  }

  if (!(channel->mFlags & DATA_CHANNEL_FLAGS_EXTERNAL_NEGOTIATED)) {
    if (!SendOpenRequestMessage(channel->mLabel, channel->mProtocol,
                                stream,
                                !!(channel->mFlags & DATA_CHANNEL_FLAGS_OUT_OF_ORDER_ALLOWED),
                                channel->mPrPolicy, channel->mPrValue)) {
      LOG(("SendOpenRequest failed, errno = %d", errno));
      if (errno == EAGAIN || errno == EWOULDBLOCK) {
        channel->mFlags |= DATA_CHANNEL_FLAGS_SEND_REQ;
        // Note: we're locked, so there's no danger of a race with the
        // buffer-threshold callback
        return channel.forget();
      } else {
        if (channel->mFlags & DATA_CHANNEL_FLAGS_FINISH_OPEN) {
          // We already returned the channel to the app.
          NS_ERROR("Failed to send open request");
          NS_DispatchToMainThread(do_AddRef(new DataChannelOnMessageAvailable(
                                    DataChannelOnMessageAvailable::ON_CHANNEL_CLOSED, this,
                                    channel)));
        }
        // If we haven't returned the channel yet, it will get destroyed when we exit
        // this function.
        mStreams[stream] = nullptr;
        channel->mStream = INVALID_STREAM;
        // we'll be destroying the channel
        channel->mState = CLOSED;
        return nullptr;
      }
      /* NOTREACHED */
    }
  }
  // Either externally negotiated or we sent Open
  channel->mState = OPEN;
  channel->mReady = true;
  // FIX?  Move into DOMDataChannel?  I don't think we can send it yet here
  LOG(("%s: sending ON_CHANNEL_OPEN for %p", __FUNCTION__, channel.get()));
  NS_DispatchToMainThread(do_AddRef(new DataChannelOnMessageAvailable(
                            DataChannelOnMessageAvailable::ON_CHANNEL_OPEN, this,
                            channel)));

  return channel.forget();

request_error_cleanup:
  channel->mState = CLOSED;
  if (channel->mFlags & DATA_CHANNEL_FLAGS_FINISH_OPEN) {
    // We already returned the channel to the app.
    NS_ERROR("Failed to request more streams");
    NS_DispatchToMainThread(do_AddRef(new DataChannelOnMessageAvailable(
                              DataChannelOnMessageAvailable::ON_CHANNEL_CLOSED, this,
                              channel)));
    return channel.forget();
  }
  // we'll be destroying the channel, but it never really got set up
  // Alternative would be to RUN_ON_THREAD(channel.forget(),::Destroy,...) and
  // Dispatch it to ourselves
  return nullptr;
}

int32_t
DataChannelConnection::SendMsgInternal(DataChannel *channel, const char *data,
                                       size_t length, uint32_t ppid)
{
  uint16_t flags;
  struct sctp_sendv_spa spa;
  int32_t result;

  NS_ENSURE_TRUE(channel->mState == OPEN || channel->mState == CONNECTING, 0);
  NS_WARNING_ASSERTION(length > 0, "Length is 0?!");

  // To avoid problems where an in-order OPEN is lost and an
  // out-of-order data message "beats" it, require data to be in-order
  // until we get an ACK.
  if ((channel->mFlags & DATA_CHANNEL_FLAGS_OUT_OF_ORDER_ALLOWED) &&
      !(channel->mFlags & DATA_CHANNEL_FLAGS_WAITING_ACK)) {
    flags = SCTP_UNORDERED;
  } else {
    flags = 0;
  }

  spa.sendv_sndinfo.snd_ppid = htonl(ppid);
  spa.sendv_sndinfo.snd_sid = channel->mStream;
  spa.sendv_sndinfo.snd_flags = flags;
  spa.sendv_sndinfo.snd_context = 0;
  spa.sendv_sndinfo.snd_assoc_id = 0;
  spa.sendv_flags = SCTP_SEND_SNDINFO_VALID;

  if (channel->mPrPolicy != SCTP_PR_SCTP_NONE) {
    spa.sendv_prinfo.pr_policy = channel->mPrPolicy;
    spa.sendv_prinfo.pr_value = channel->mPrValue;
    spa.sendv_flags |= SCTP_SEND_PRINFO_VALID;
  }

  // Note: Main-thread IO, but doesn't block!
  // XXX FIX!  to deal with heavy overruns of JS trying to pass data in
  // (more than the buffersize) queue data onto another thread to do the
  // actual sends.  See netwerk/protocol/websocket/WebSocketChannel.cpp

  // SCTP will return EMSGSIZE if the message is bigger than the buffer
  // size (or EAGAIN if there isn't space)

  // Avoid a race between buffer-full-failure (where we have to add the
  // packet to the buffered-data queue) and the buffer-now-only-half-full
  // callback, which happens on a different thread.  Otherwise we might
  // fail here, then before we add it to the queue get the half-full
  // callback, find nothing to do, then on this thread add it to the
  // queue - which would sit there.  Also, if we later send more data, it
  // would arrive ahead of the buffered message, but if the buffer ever
  // got to 1/2 full, the message would get sent - but at a semi-random
  // time, after other data it was supposed to be in front of.

  // Must lock before empty check for similar reasons!
  MutexAutoLock lock(mLock);
  if (channel->mBufferedData.IsEmpty()) {
    result = usrsctp_sendv(mSocket, data, length,
                           nullptr, 0,
                           (void *)&spa, (socklen_t)sizeof(struct sctp_sendv_spa),
                           SCTP_SENDV_SPA, 0);
    LOG(("Sent buffer (len=%u), result=%d", length, result));
  } else {
    // Fake EAGAIN if we're already buffering data
    result = -1;
    errno = EAGAIN;
  }
  if (result < 0) {
    if (errno == EAGAIN || errno == EWOULDBLOCK) {

      // queue data for resend!  And queue any further data for the stream until it is...
      auto *buffered = new BufferedMsg(spa, data, length); // infallible malloc
      channel->mBufferedData.AppendElement(buffered); // owned by mBufferedData array
      channel->mFlags |= DATA_CHANNEL_FLAGS_SEND_DATA;
      LOG(("Queued %u buffers (len=%u)", channel->mBufferedData.Length(), length));
      return 0;
    }
    LOG(("error %d sending string", errno));
  }
  return result;
}

// Handles fragmenting binary messages
int32_t
DataChannelConnection::SendBinary(DataChannel *channel, const char *data,
                                  size_t len,
                                  uint32_t ppid_partial, uint32_t ppid_final)
{
  // Since there's a limit on network buffer size and no limits on message
  // size, and we don't want to use EOR mode (multiple writes for a
  // message, but all other streams are blocked until you finish sending
  // this message), we need to add application-level fragmentation of large
  // messages.  On a reliable channel, these can be simply rebuilt into a
  // large message.  On an unreliable channel, we can't and don't know how
  // long to wait, and there are no retransmissions, and no easy way to
  // tell the user "this part is missing", so on unreliable channels we
  // need to return an error if sending more bytes than the network buffers
  // can hold, and perhaps a lower number.

  // We *really* don't want to do this from main thread! - and SendMsgInternal
  // avoids blocking.
  // This MUST be reliable and in-order for the reassembly to work
  if (len > DATA_CHANNEL_MAX_BINARY_FRAGMENT &&
      channel->mPrPolicy == DATA_CHANNEL_RELIABLE &&
      !(channel->mFlags & DATA_CHANNEL_FLAGS_OUT_OF_ORDER_ALLOWED)) {
    int32_t sent=0;
    uint32_t origlen = len;
    LOG(("Sending binary message length %u in chunks", len));
    // XXX check flags for out-of-order, or force in-order for large binary messages
    while (len > 0) {
      size_t sendlen = std::min<size_t>(len, DATA_CHANNEL_MAX_BINARY_FRAGMENT);
      uint32_t ppid;
      len -= sendlen;
      ppid = len > 0 ? ppid_partial : ppid_final;
      LOG(("Send chunk of %u bytes, ppid %u", sendlen, ppid));
      // Note that these might end up being deferred and queued.
      sent += SendMsgInternal(channel, data, sendlen, ppid);
      data += sendlen;
    }
    LOG(("Sent %d buffers for %u bytes, %d sent immediately, %d buffers queued",
         (origlen+DATA_CHANNEL_MAX_BINARY_FRAGMENT-1)/DATA_CHANNEL_MAX_BINARY_FRAGMENT,
         origlen, sent,
         channel->mBufferedData.Length()));
    return sent;
  }
  NS_WARNING_ASSERTION(len <= DATA_CHANNEL_MAX_BINARY_FRAGMENT,
                       "Sending too-large data on unreliable channel!");

  // This will fail if the message is too large (default 256K)
  return SendMsgInternal(channel, data, len, ppid_final);
}

class ReadBlobRunnable : public Runnable {
public:
  ReadBlobRunnable(DataChannelConnection* aConnection, uint16_t aStream,
    nsIInputStream* aBlob) :
    mConnection(aConnection),
    mStream(aStream),
    mBlob(aBlob)
  {}

  NS_IMETHOD Run() override {
    // ReadBlob() is responsible to releasing the reference
    DataChannelConnection *self = mConnection;
    self->ReadBlob(mConnection.forget(), mStream, mBlob);
    return NS_OK;
  }

private:
  // Make sure the Connection doesn't die while there are jobs outstanding.
  // Let it die (if released by PeerConnectionImpl while we're running)
  // when we send our runnable back to MainThread.  Then ~DataChannelConnection
  // can send the IOThread to MainThread to die in a runnable, avoiding
  // unsafe event loop recursion.  Evil.
  RefPtr<DataChannelConnection> mConnection;
  uint16_t mStream;
  // Use RefCount for preventing the object is deleted when SendBlob returns.
  RefPtr<nsIInputStream> mBlob;
};

int32_t
DataChannelConnection::SendBlob(uint16_t stream, nsIInputStream *aBlob)
{
  DataChannel *channel = mStreams[stream];
  NS_ENSURE_TRUE(channel, 0);
  // Spawn a thread to send the data
  if (!mInternalIOThread) {
    nsresult res = NS_NewThread(getter_AddRefs(mInternalIOThread));
    if (NS_FAILED(res)) {
      return -1;
    }
  }

  mInternalIOThread->Dispatch(do_AddRef(new ReadBlobRunnable(this, stream, aBlob)), NS_DISPATCH_NORMAL);
  return 0;
}

class DataChannelBlobSendRunnable : public Runnable
{
public:
  DataChannelBlobSendRunnable(already_AddRefed<DataChannelConnection>& aConnection,
                              uint16_t aStream)
    : mConnection(aConnection)
    , mStream(aStream) {}

  ~DataChannelBlobSendRunnable() override
  {
    if (!NS_IsMainThread() && mConnection) {
      MOZ_ASSERT(false);
      // explicitly leak the connection if destroyed off mainthread
      Unused << mConnection.forget().take();
    }
  }

  NS_IMETHOD Run() override
  {
    ASSERT_WEBRTC(NS_IsMainThread());

    mConnection->SendBinaryMsg(mStream, mData);
    mConnection = nullptr;
    return NS_OK;
  }

  // explicitly public so we can avoid allocating twice and copying
  nsCString mData;

private:
  // Note: we can be destroyed off the target thread, so be careful not to let this
  // get Released()ed on the temp thread!
  RefPtr<DataChannelConnection> mConnection;
  uint16_t mStream;
};

void
DataChannelConnection::ReadBlob(already_AddRefed<DataChannelConnection> aThis,
                                uint16_t aStream, nsIInputStream* aBlob)
{
  // NOTE: 'aThis' has been forgotten by the caller to avoid releasing
  // it off mainthread; if PeerConnectionImpl has released then we want
  // ~DataChannelConnection() to run on MainThread

  // XXX to do this safely, we must enqueue these atomically onto the
  // output socket.  We need a sender thread(s?) to enqueue data into the
  // socket and to avoid main-thread IO that might block.  Even on a
  // background thread, we may not want to block on one stream's data.
  // I.e. run non-blocking and service multiple channels.

  // For now as a hack, send as a single blast of queued packets which may
  // be deferred until buffer space is available.
  uint64_t len;
  nsCOMPtr<nsIThread> mainThread;
  NS_GetMainThread(getter_AddRefs(mainThread));

  // Must not let Dispatching it cause the DataChannelConnection to get
  // released on the wrong thread.  Using WrapRunnable(RefPtr<DataChannelConnection>(aThis),...
  // will occasionally cause aThis to get released on this thread.  Also, an explicit Runnable
  // lets us avoid copying the blob data an extra time.
  RefPtr<DataChannelBlobSendRunnable> runnable = new DataChannelBlobSendRunnable(aThis,
                                                                                   aStream);
  // avoid copying the blob data by passing the mData from the runnable
  if (NS_FAILED(aBlob->Available(&len)) ||
      NS_FAILED(NS_ReadInputStreamToString(aBlob, runnable->mData, len))) {
    // Bug 966602:  Doesn't return an error to the caller via onerror.
    // We must release DataChannelConnection on MainThread to avoid issues (bug 876167)
    // aThis is now owned by the runnable; release it there
    NS_ProxyRelease(mainThread, runnable.forget());
    return;
  }
  aBlob->Close();
  NS_DispatchToMainThread(runnable, NS_DISPATCH_NORMAL);
}

void
DataChannelConnection::GetStreamIds(std::vector<uint16_t>* aStreamList)
{
  ASSERT_WEBRTC(NS_IsMainThread());
  for (uint32_t i = 0; i < mStreams.Length(); ++i) {
    if (mStreams[i]) {
      aStreamList->push_back(mStreams[i]->mStream);
    }
  }
}

int32_t
DataChannelConnection::SendMsgCommon(uint16_t stream, const nsACString &aMsg,
                                     bool isBinary)
{
  ASSERT_WEBRTC(NS_IsMainThread());
  // We really could allow this from other threads, so long as we deal with
  // asynchronosity issues with channels closing, in particular access to
  // mStreams, and issues with the association closing (access to mSocket).

  const char *data = aMsg.BeginReading();
  uint32_t len     = aMsg.Length();
  DataChannel *channel;

  LOG(("Sending %sto stream %u: %u bytes", isBinary ? "binary " : "", stream, len));
  // XXX if we want more efficiency, translate flags once at open time
  channel = mStreams[stream];
  NS_ENSURE_TRUE(channel, 0);

  if (isBinary)
    return SendBinary(channel, data, len,
                      DATA_CHANNEL_PPID_BINARY, DATA_CHANNEL_PPID_BINARY_LAST);
  return SendBinary(channel, data, len,
                    DATA_CHANNEL_PPID_DOMSTRING, DATA_CHANNEL_PPID_DOMSTRING_LAST);
}

void
DataChannelConnection::Close(DataChannel *aChannel)
{
  MutexAutoLock lock(mLock);
  CloseInt(aChannel);
}

// So we can call Close() with the lock already held
// Called from someone who holds a ref via ::Close(), or from ~DataChannel
void
DataChannelConnection::CloseInt(DataChannel *aChannel)
{
  MOZ_ASSERT(aChannel);
  RefPtr<DataChannel> channel(aChannel); // make sure it doesn't go away on us

  mLock.AssertCurrentThreadOwns();
  LOG(("Connection %p/Channel %p: Closing stream %u",
       channel->mConnection.get(), channel.get(), channel->mStream));
  // re-test since it may have closed before the lock was grabbed
  if (aChannel->mState == CLOSED || aChannel->mState == CLOSING) {
    LOG(("Channel already closing/closed (%u)", aChannel->mState));
    if (mState == CLOSED && channel->mStream != INVALID_STREAM) {
      // called from CloseAll()
      // we're not going to hang around waiting any more
      mStreams[channel->mStream] = nullptr;
    }
    return;
  }
  aChannel->mBufferedData.Clear();
  if (channel->mStream != INVALID_STREAM) {
    ResetOutgoingStream(channel->mStream);
    if (mState == CLOSED) { // called from CloseAll()
      // Let resets accumulate then send all at once in CloseAll()
      // we're not going to hang around waiting
      mStreams[channel->mStream] = nullptr;
    } else {
      SendOutgoingStreamReset();
    }
  }
  aChannel->mState = CLOSING;
  if (mState == CLOSED) {
    // we're not going to hang around waiting
    channel->StreamClosedLocked();
  }
  // At this point when we leave here, the object is a zombie held alive only by the DOM object
}

void DataChannelConnection::CloseAll()
{
  LOG(("Closing all channels (connection %p)", (void*) this));
  // Don't need to lock here

  // Make sure no more channels will be opened
  {
    MutexAutoLock lock(mLock);
    mState = CLOSED;
  }

  // Close current channels
  // If there are runnables, they hold a strong ref and keep the channel
  // and/or connection alive (even if in a CLOSED state)
  bool closed_some = false;
  for (uint32_t i = 0; i < mStreams.Length(); ++i) {
    if (mStreams[i]) {
      mStreams[i]->Close();
      closed_some = true;
    }
  }

  // Clean up any pending opens for channels
  RefPtr<DataChannel> channel;
  while (nullptr != (channel = dont_AddRef(static_cast<DataChannel *>(mPending.PopFront())))) {
    LOG(("closing pending channel %p, stream %u", channel.get(), channel->mStream));
    channel->Close(); // also releases the ref on each iteration
    closed_some = true;
  }
  // It's more efficient to let the Resets queue in shutdown and then
  // SendOutgoingStreamReset() here.
  if (closed_some) {
    MutexAutoLock lock(mLock);
    SendOutgoingStreamReset();
  }
}

DataChannel::~DataChannel()
{
  // NS_ASSERTION since this is more "I think I caught all the cases that
  // can cause this" than a true kill-the-program assertion.  If this is
  // wrong, nothing bad happens.  A worst it's a leak.
  NS_ASSERTION(mState == CLOSED || mState == CLOSING, "unexpected state in ~DataChannel");
}

void
DataChannel::Close()
{
  if (mConnection) {
    // ensure we don't get deleted
    RefPtr<DataChannelConnection> connection(mConnection);
    connection->Close(this);
  }
}

// Used when disconnecting from the DataChannelConnection
void
DataChannel::StreamClosedLocked()
{
  mConnection->mLock.AssertCurrentThreadOwns();
  ENSURE_DATACONNECTION;

  LOG(("Destroying Data channel %u", mStream));
  MOZ_ASSERT_IF(mStream != INVALID_STREAM,
                !mConnection->FindChannelByStream(mStream));
  mStream = INVALID_STREAM;
  mState = CLOSED;
  NS_DispatchToMainThread(do_AddRef(new DataChannelOnMessageAvailable(
                                      DataChannelOnMessageAvailable::ON_CHANNEL_CLOSED,
                                      mConnection, this)));
  // We leave mConnection live until the DOM releases us, to avoid races
}

void
DataChannel::ReleaseConnection()
{
  ASSERT_WEBRTC(NS_IsMainThread());
  mConnection = nullptr;
}

void
DataChannel::SetListener(DataChannelListener *aListener, nsISupports *aContext)
{
  MutexAutoLock mLock(mListenerLock);
  mContext = aContext;
  mListener = aListener;
}

// May be called from another (i.e. Main) thread!
void
DataChannel::AppReady()
{
  ENSURE_DATACONNECTION;

  MutexAutoLock lock(mConnection->mLock);

  mReady = true;
  if (mState == WAITING_TO_OPEN) {
    mState = OPEN;
    NS_DispatchToMainThread(do_AddRef(new DataChannelOnMessageAvailable(
                              DataChannelOnMessageAvailable::ON_CHANNEL_OPEN, mConnection,
                              this)));
    for (uint32_t i = 0; i < mQueuedMessages.Length(); ++i) {
      nsCOMPtr<nsIRunnable> runnable = mQueuedMessages[i];
      MOZ_ASSERT(runnable);
      NS_DispatchToMainThread(runnable);
    }
  } else {
    NS_ASSERTION(mQueuedMessages.IsEmpty(), "Shouldn't have queued messages if not WAITING_TO_OPEN");
  }
  mQueuedMessages.Clear();
  mQueuedMessages.Compact();
  // We never use it again...  We could even allocate the array in the odd
  // cases we need it.
}

uint32_t
DataChannel::GetBufferedAmountLocked() const
{
  size_t buffered = 0;

  for (auto& buffer : mBufferedData) {
    buffered += buffer->mLength;
  }
  // XXX Note: per Michael Tuexen, there's no way to currently get the buffered
  // amount from the SCTP stack for a single stream.  It is on their to-do
  // list, and once we import a stack with support for that, we'll need to
  // add it to what we buffer.  Also we'll need to ask for notification of a per-
  // stream buffer-low event and merge that into the handling of buffer-low
  // (the equivalent to TCP_NOTSENT_LOWAT on TCP sockets)

  if (buffered > UINT32_MAX) { // paranoia - >4GB buffered is very very unlikely
    buffered = UINT32_MAX;
  }
  return buffered;
}

uint32_t
DataChannel::GetBufferedAmountLowThreshold()
{
  return mBufferedThreshold;
}

// Never fire immediately, as it's defined to fire on transitions, not state
void
DataChannel::SetBufferedAmountLowThreshold(uint32_t aThreshold)
{
  mBufferedThreshold = aThreshold;
}

// Called with mLock locked!
void
DataChannel::SendOrQueue(DataChannelOnMessageAvailable *aMessage)
{
  if (!mReady &&
      (mState == CONNECTING || mState == WAITING_TO_OPEN)) {
    mQueuedMessages.AppendElement(aMessage);
  } else {
    NS_DispatchToMainThread(aMessage);
  }
}

} // namespace mozilla