summaryrefslogtreecommitdiff
path: root/include/net/sctp/structs.h
blob: ce93c4b10d2620a3ac4c9efe39a86e5d231b51c2 (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
/* SCTP kernel implementation
 * (C) Copyright IBM Corp. 2001, 2004
 * Copyright (c) 1999-2000 Cisco, Inc.
 * Copyright (c) 1999-2001 Motorola, Inc.
 * Copyright (c) 2001 Intel Corp.
 *
 * This file is part of the SCTP kernel implementation
 *
 * This SCTP implementation is free software;
 * you can redistribute it and/or modify it under the terms of
 * the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This SCTP implementation is distributed in the hope that it
 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
 *		   ************************
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU CC; see the file COPYING.  If not, see
 * <http://www.gnu.org/licenses/>.
 *
 * Please send any bug reports or fixes you make to the
 * email addresses:
 *    lksctp developers <linux-sctp@vger.kernel.org>
 *
 * Written or modified by:
 *    Randall Stewart	    <randall@sctp.chicago.il.us>
 *    Ken Morneau	    <kmorneau@cisco.com>
 *    Qiaobing Xie	    <qxie1@email.mot.com>
 *    La Monte H.P. Yarroll <piggy@acm.org>
 *    Karl Knutson	    <karl@athena.chicago.il.us>
 *    Jon Grimm		    <jgrimm@us.ibm.com>
 *    Xingang Guo	    <xingang.guo@intel.com>
 *    Hui Huang		    <hui.huang@nokia.com>
 *    Sridhar Samudrala	    <sri@us.ibm.com>
 *    Daisy Chang	    <daisyc@us.ibm.com>
 *    Dajiang Zhang	    <dajiang.zhang@nokia.com>
 *    Ardelle Fan	    <ardelle.fan@intel.com>
 *    Ryan Layer	    <rmlayer@us.ibm.com>
 *    Anup Pemmaiah	    <pemmaiah@cc.usu.edu>
 *    Kevin Gao             <kevin.gao@intel.com>
 */

#ifndef __sctp_structs_h__
#define __sctp_structs_h__

#include <linux/ktime.h>
#include <linux/rhashtable.h>
#include <linux/socket.h>	/* linux/in.h needs this!!    */
#include <linux/in.h>		/* We get struct sockaddr_in. */
#include <linux/in6.h>		/* We get struct in6_addr     */
#include <linux/ipv6.h>
#include <asm/param.h>		/* We get MAXHOSTNAMELEN.     */
#include <linux/atomic.h>		/* This gets us atomic counters.  */
#include <linux/skbuff.h>	/* We need sk_buff_head. */
#include <linux/workqueue.h>	/* We need tq_struct.	 */
#include <linux/sctp.h>		/* We need sctp* header structs.  */
#include <net/sctp/auth.h>	/* We need auth specific structs */
#include <net/ip.h>		/* For inet_skb_parm */

/* A convenience structure for handling sockaddr structures.
 * We should wean ourselves off this.
 */
union sctp_addr {
	struct sockaddr_in v4;
	struct sockaddr_in6 v6;
	struct sockaddr sa;
};

/* Forward declarations for data structures. */
struct sctp_globals;
struct sctp_endpoint;
struct sctp_association;
struct sctp_transport;
struct sctp_packet;
struct sctp_chunk;
struct sctp_inq;
struct sctp_outq;
struct sctp_bind_addr;
struct sctp_ulpq;
struct sctp_ep_common;
struct sctp_ssnmap;
struct crypto_shash;


#include <net/sctp/tsnmap.h>
#include <net/sctp/ulpevent.h>
#include <net/sctp/ulpqueue.h>

/* Structures useful for managing bind/connect. */

struct sctp_bind_bucket {
	unsigned short	port;
	unsigned short	fastreuse;
	struct hlist_node	node;
	struct hlist_head	owner;
	struct net	*net;
};

struct sctp_bind_hashbucket {
	spinlock_t	lock;
	struct hlist_head	chain;
};

/* Used for hashing all associations.  */
struct sctp_hashbucket {
	rwlock_t	lock;
	struct hlist_head	chain;
} __attribute__((__aligned__(8)));


/* The SCTP globals structure. */
extern struct sctp_globals {
	/* This is a list of groups of functions for each address
	 * family that we support.
	 */
	struct list_head address_families;

	/* This is the hash of all endpoints. */
	struct sctp_hashbucket *ep_hashtable;
	/* This is the sctp port control hash.	*/
	struct sctp_bind_hashbucket *port_hashtable;
	/* This is the hash of all transports. */
	struct rhashtable transport_hashtable;

	/* Sizes of above hashtables. */
	int ep_hashsize;
	int port_hashsize;

	/* Default initialization values to be applied to new associations. */
	__u16 max_instreams;
	__u16 max_outstreams;

	/* Flag to indicate whether computing and verifying checksum
	 * is disabled. */
        bool checksum_disable;
} sctp_globals;

#define sctp_max_instreams		(sctp_globals.max_instreams)
#define sctp_max_outstreams		(sctp_globals.max_outstreams)
#define sctp_address_families		(sctp_globals.address_families)
#define sctp_ep_hashsize		(sctp_globals.ep_hashsize)
#define sctp_ep_hashtable		(sctp_globals.ep_hashtable)
#define sctp_port_hashsize		(sctp_globals.port_hashsize)
#define sctp_port_hashtable		(sctp_globals.port_hashtable)
#define sctp_transport_hashtable	(sctp_globals.transport_hashtable)
#define sctp_checksum_disable		(sctp_globals.checksum_disable)

/* SCTP Socket type: UDP or TCP style. */
typedef enum {
	SCTP_SOCKET_UDP = 0,
	SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
	SCTP_SOCKET_TCP
} sctp_socket_type_t;

/* Per socket SCTP information. */
struct sctp_sock {
	/* inet_sock has to be the first member of sctp_sock */
	struct inet_sock inet;
	/* What kind of a socket is this? */
	sctp_socket_type_t type;

	/* PF_ family specific functions.  */
	struct sctp_pf *pf;

	/* Access to HMAC transform. */
	struct crypto_shash *hmac;
	char *sctp_hmac_alg;

	/* What is our base endpointer? */
	struct sctp_endpoint *ep;

	struct sctp_bind_bucket *bind_hash;
	/* Various Socket Options.  */
	__u16 default_stream;
	__u32 default_ppid;
	__u16 default_flags;
	__u32 default_context;
	__u32 default_timetolive;
	__u32 default_rcv_context;
	int max_burst;

	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
	 * the destination address every heartbeat interval. This value
	 * will be inherited by all new associations.
	 */
	__u32 hbinterval;

	/* This is the max_retrans value for new associations. */
	__u16 pathmaxrxt;

	/* The initial Path MTU to use for new associations. */
	__u32 pathmtu;

	/* The default SACK delay timeout for new associations. */
	__u32 sackdelay;
	__u32 sackfreq;

	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
	__u32 param_flags;

	struct sctp_initmsg initmsg;
	struct sctp_rtoinfo rtoinfo;
	struct sctp_paddrparams paddrparam;
	struct sctp_event_subscribe subscribe;
	struct sctp_assocparams assocparams;

	int user_frag;

	__u32 autoclose;
	__u32 adaptation_ind;
	__u32 pd_point;
	__u16	nodelay:1,
		disable_fragments:1,
		v4mapped:1,
		frag_interleave:1,
		recvrcvinfo:1,
		recvnxtinfo:1,
		data_ready_signalled:1;

	atomic_t pd_mode;
	/* Receive to here while partial delivery is in effect. */
	struct sk_buff_head pd_lobby;

	/* These must be the last fields, as they will skipped on copies,
	 * like on accept and peeloff operations
	 */
	struct list_head auto_asconf_list;
	int do_auto_asconf;
};

static inline struct sctp_sock *sctp_sk(const struct sock *sk)
{
       return (struct sctp_sock *)sk;
}

static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
{
       return (struct sock *)sp;
}

#if IS_ENABLED(CONFIG_IPV6)
struct sctp6_sock {
       struct sctp_sock  sctp;
       struct ipv6_pinfo inet6;
};
#endif /* CONFIG_IPV6 */


/* This is our APPLICATION-SPECIFIC state cookie.
 * THIS IS NOT DICTATED BY THE SPECIFICATION.
 */
/* These are the parts of an association which we send in the cookie.
 * Most of these are straight out of:
 * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
 *
 */

struct sctp_cookie {

	/* My	       : Tag expected in every inbound packet and sent
	 * Verification: in the INIT or INIT ACK chunk.
	 * Tag	       :
	 */
	__u32 my_vtag;

	/* Peer's      : Tag expected in every outbound packet except
	 * Verification: in the INIT chunk.
	 * Tag	       :
	 */
	__u32 peer_vtag;

	/* The rest of these are not from the spec, but really need to
	 * be in the cookie.
	 */

	/* My Tie Tag  : Assist in discovering a restarting association. */
	__u32 my_ttag;

	/* Peer's Tie Tag: Assist in discovering a restarting association. */
	__u32 peer_ttag;

	/* When does this cookie expire? */
	ktime_t expiration;

	/* Number of inbound/outbound streams which are set
	 * and negotiated during the INIT process.
	 */
	__u16 sinit_num_ostreams;
	__u16 sinit_max_instreams;

	/* This is the first sequence number I used.  */
	__u32 initial_tsn;

	/* This holds the originating address of the INIT packet.  */
	union sctp_addr peer_addr;

	/* IG Section 2.35.3 
	 * Include the source port of the INIT-ACK
	 */
	__u16		my_port;

	__u8 prsctp_capable;

	/* Padding for future use */
	__u8 padding;  		

	__u32 adaptation_ind;

	__u8 auth_random[sizeof(sctp_paramhdr_t) + SCTP_AUTH_RANDOM_LENGTH];
	__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
	__u8 auth_chunks[sizeof(sctp_paramhdr_t) + SCTP_AUTH_MAX_CHUNKS];

	/* This is a shim for my peer's INIT packet, followed by
	 * a copy of the raw address list of the association.
	 * The length of the raw address list is saved in the
	 * raw_addr_list_len field, which will be used at the time when
	 * the association TCB is re-constructed from the cookie.
	 */
	__u32 raw_addr_list_len;
	struct sctp_init_chunk peer_init[0];
};


/* The format of our cookie that we send to our peer. */
struct sctp_signed_cookie {
	__u8 signature[SCTP_SECRET_SIZE];
	__u32 __pad;		/* force sctp_cookie alignment to 64 bits */
	struct sctp_cookie c;
} __packed;

/* This is another convenience type to allocate memory for address
 * params for the maximum size and pass such structures around
 * internally.
 */
union sctp_addr_param {
	struct sctp_paramhdr p;
	struct sctp_ipv4addr_param v4;
	struct sctp_ipv6addr_param v6;
};

/* A convenience type to allow walking through the various
 * parameters and avoid casting all over the place.
 */
union sctp_params {
	void *v;
	struct sctp_paramhdr *p;
	struct sctp_cookie_preserve_param *life;
	struct sctp_hostname_param *dns;
	struct sctp_cookie_param *cookie;
	struct sctp_supported_addrs_param *sat;
	struct sctp_ipv4addr_param *v4;
	struct sctp_ipv6addr_param *v6;
	union sctp_addr_param *addr;
	struct sctp_adaptation_ind_param *aind;
	struct sctp_supported_ext_param *ext;
	struct sctp_random_param *random;
	struct sctp_chunks_param *chunks;
	struct sctp_hmac_algo_param *hmac_algo;
	struct sctp_addip_param *addip;
};

/* RFC 2960.  Section 3.3.5 Heartbeat.
 *    Heartbeat Information: variable length
 *    The Sender-specific Heartbeat Info field should normally include
 *    information about the sender's current time when this HEARTBEAT
 *    chunk is sent and the destination transport address to which this
 *    HEARTBEAT is sent (see Section 8.3).
 */
typedef struct sctp_sender_hb_info {
	struct sctp_paramhdr param_hdr;
	union sctp_addr daddr;
	unsigned long sent_at;
	__u64 hb_nonce;
} __packed sctp_sender_hb_info_t;

/*
 *  RFC 2960 1.3.2 Sequenced Delivery within Streams
 *
 *  The term "stream" is used in SCTP to refer to a sequence of user
 *  messages that are to be delivered to the upper-layer protocol in
 *  order with respect to other messages within the same stream.  This is
 *  in contrast to its usage in TCP, where it refers to a sequence of
 *  bytes (in this document a byte is assumed to be eight bits).
 *  ...
 *
 *  This is the structure we use to track both our outbound and inbound
 *  SSN, or Stream Sequence Numbers.
 */

struct sctp_stream {
	__u16 *ssn;
	unsigned int len;
};

struct sctp_ssnmap {
	struct sctp_stream in;
	struct sctp_stream out;
};

struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out,
				    gfp_t gfp);
void sctp_ssnmap_free(struct sctp_ssnmap *map);
void sctp_ssnmap_clear(struct sctp_ssnmap *map);

/* What is the current SSN number for this stream? */
static inline __u16 sctp_ssn_peek(struct sctp_stream *stream, __u16 id)
{
	return stream->ssn[id];
}

/* Return the next SSN number for this stream.	*/
static inline __u16 sctp_ssn_next(struct sctp_stream *stream, __u16 id)
{
	return stream->ssn[id]++;
}

/* Skip over this ssn and all below. */
static inline void sctp_ssn_skip(struct sctp_stream *stream, __u16 id, 
				 __u16 ssn)
{
	stream->ssn[id] = ssn+1;
}
              
/*
 * Pointers to address related SCTP functions.
 * (i.e. things that depend on the address family.)
 */
struct sctp_af {
	int		(*sctp_xmit)	(struct sk_buff *skb,
					 struct sctp_transport *);
	int		(*setsockopt)	(struct sock *sk,
					 int level,
					 int optname,
					 char __user *optval,
					 unsigned int optlen);
	int		(*getsockopt)	(struct sock *sk,
					 int level,
					 int optname,
					 char __user *optval,
					 int __user *optlen);
	int		(*compat_setsockopt)	(struct sock *sk,
					 int level,
					 int optname,
					 char __user *optval,
					 unsigned int optlen);
	int		(*compat_getsockopt)	(struct sock *sk,
					 int level,
					 int optname,
					 char __user *optval,
					 int __user *optlen);
	void		(*get_dst)	(struct sctp_transport *t,
					 union sctp_addr *saddr,
					 struct flowi *fl,
					 struct sock *sk);
	void		(*get_saddr)	(struct sctp_sock *sk,
					 struct sctp_transport *t,
					 struct flowi *fl);
	void		(*copy_addrlist) (struct list_head *,
					  struct net_device *);
	int		(*cmp_addr)	(const union sctp_addr *addr1,
					 const union sctp_addr *addr2);
	void		(*addr_copy)	(union sctp_addr *dst,
					 union sctp_addr *src);
	void		(*from_skb)	(union sctp_addr *,
					 struct sk_buff *skb,
					 int saddr);
	void		(*from_sk)	(union sctp_addr *,
					 struct sock *sk);
	void		(*from_addr_param) (union sctp_addr *,
					    union sctp_addr_param *,
					    __be16 port, int iif);
	int		(*to_addr_param) (const union sctp_addr *,
					  union sctp_addr_param *); 
	int		(*addr_valid)	(union sctp_addr *,
					 struct sctp_sock *,
					 const struct sk_buff *);
	sctp_scope_t	(*scope) (union sctp_addr *);
	void		(*inaddr_any)	(union sctp_addr *, __be16);
	int		(*is_any)	(const union sctp_addr *);
	int		(*available)	(union sctp_addr *,
					 struct sctp_sock *);
	int		(*skb_iif)	(const struct sk_buff *sk);
	int		(*is_ce)	(const struct sk_buff *sk);
	void		(*seq_dump_addr)(struct seq_file *seq,
					 union sctp_addr *addr);
	void		(*ecn_capable)(struct sock *sk);
	__u16		net_header_len;
	int		sockaddr_len;
	sa_family_t	sa_family;
	struct list_head list;
};

struct sctp_af *sctp_get_af_specific(sa_family_t);
int sctp_register_af(struct sctp_af *);

/* Protocol family functions. */
struct sctp_pf {
	void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
	void (*skb_msgname)  (struct sk_buff *, char *, int *);
	int  (*af_supported) (sa_family_t, struct sctp_sock *);
	int  (*cmp_addr) (const union sctp_addr *,
			  const union sctp_addr *,
			  struct sctp_sock *);
	int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
	int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
	int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
	struct sock *(*create_accept_sk) (struct sock *sk,
					  struct sctp_association *asoc);
	int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
	void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
	void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
	struct sctp_af *af;
};


/* Structure to track chunk fragments that have been acked, but peer
 * fragments of the same message have not.
 */
struct sctp_datamsg {
	/* Chunks waiting to be submitted to lower layer. */
	struct list_head chunks;
	/* Reference counting. */
	atomic_t refcnt;
	/* When is this message no longer interesting to the peer? */
	unsigned long expires_at;
	/* Did the messenge fail to send? */
	int send_error;
	u8 send_failed:1,
	   can_abandon:1,   /* can chunks from this message can be abandoned. */
	   can_delay;	    /* should this message be Nagle delayed */
};

struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
					    struct sctp_sndrcvinfo *,
					    struct iov_iter *);
void sctp_datamsg_put(struct sctp_datamsg *);
void sctp_chunk_fail(struct sctp_chunk *, int error);
int sctp_chunk_abandoned(struct sctp_chunk *);

/* RFC2960 1.4 Key Terms
 *
 * o Chunk: A unit of information within an SCTP packet, consisting of
 * a chunk header and chunk-specific content.
 *
 * As a matter of convenience, we remember the SCTP common header for
 * each chunk as well as a few other header pointers...
 */
struct sctp_chunk {
	struct list_head list;

	atomic_t refcnt;

	/* This is our link to the per-transport transmitted list.  */
	struct list_head transmitted_list;

	/* This field is used by chunks that hold fragmented data.
	 * For the first fragment this is the list that holds the rest of
	 * fragments. For the remaining fragments, this is the link to the
	 * frag_list maintained in the first fragment.
	 */
	struct list_head frag_list;

	/* This points to the sk_buff containing the actual data.  */
	struct sk_buff *skb;

	/* In case of GSO packets, this will store the head one */
	struct sk_buff *head_skb;

	/* These are the SCTP headers by reverse order in a packet.
	 * Note that some of these may happen more than once.  In that
	 * case, we point at the "current" one, whatever that means
	 * for that level of header.
	 */

	/* We point this at the FIRST TLV parameter to chunk_hdr.  */
	union sctp_params param_hdr;
	union {
		__u8 *v;
		struct sctp_datahdr *data_hdr;
		struct sctp_inithdr *init_hdr;
		struct sctp_sackhdr *sack_hdr;
		struct sctp_heartbeathdr *hb_hdr;
		struct sctp_sender_hb_info *hbs_hdr;
		struct sctp_shutdownhdr *shutdown_hdr;
		struct sctp_signed_cookie *cookie_hdr;
		struct sctp_ecnehdr *ecne_hdr;
		struct sctp_cwrhdr *ecn_cwr_hdr;
		struct sctp_errhdr *err_hdr;
		struct sctp_addiphdr *addip_hdr;
		struct sctp_fwdtsn_hdr *fwdtsn_hdr;
		struct sctp_authhdr *auth_hdr;
	} subh;

	__u8 *chunk_end;

	struct sctp_chunkhdr *chunk_hdr;
	struct sctphdr *sctp_hdr;

	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
	struct sctp_sndrcvinfo sinfo;

	/* We use this field to record param for prsctp policies,
	 * for TTL policy, it is the time_to_drop of this chunk,
	 * for RTX policy, it is the max_sent_count of this chunk,
	 * for PRIO policy, it is the priority of this chunk.
	 */
	unsigned long prsctp_param;

	/* How many times this chunk have been sent, for prsctp RTX policy */
	int sent_count;

	/* Which association does this belong to?  */
	struct sctp_association *asoc;

	/* What endpoint received this chunk? */
	struct sctp_ep_common *rcvr;

	/* We fill this in if we are calculating RTT. */
	unsigned long sent_at;

	/* What is the origin IP address for this chunk?  */
	union sctp_addr source;
	/* Destination address for this chunk. */
	union sctp_addr dest;

	/* For outbound message, track all fragments for SEND_FAILED. */
	struct sctp_datamsg *msg;

	/* For an inbound chunk, this tells us where it came from.
	 * For an outbound chunk, it tells us where we'd like it to
	 * go.	It is NULL if we have no preference.
	 */
	struct sctp_transport *transport;

	/* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
	 * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
	 * spec violates the principle premis that all chunks are processed
	 * in order.
	 */
	struct sk_buff *auth_chunk;

#define SCTP_CAN_FRTX 0x0
#define SCTP_NEED_FRTX 0x1
#define SCTP_DONT_FRTX 0x2
	__u16	rtt_in_progress:1,	/* This chunk used for RTT calc? */
		resent:1,		/* Has this chunk ever been resent. */
		has_tsn:1,		/* Does this chunk have a TSN yet? */
		has_ssn:1,		/* Does this chunk have a SSN yet? */
		singleton:1,		/* Only chunk in the packet? */
		end_of_packet:1,	/* Last chunk in the packet? */
		ecn_ce_done:1,		/* Have we processed the ECN CE bit? */
		pdiscard:1,		/* Discard the whole packet now? */
		tsn_gap_acked:1,	/* Is this chunk acked by a GAP ACK? */
		data_accepted:1,	/* At least 1 chunk accepted */
		auth:1,			/* IN: was auth'ed | OUT: needs auth */
		has_asconf:1,		/* IN: have seen an asconf before */
		tsn_missing_report:2,	/* Data chunk missing counter. */
		fast_retransmit:2;	/* Is this chunk fast retransmitted? */
};

void sctp_chunk_hold(struct sctp_chunk *);
void sctp_chunk_put(struct sctp_chunk *);
int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
			  struct iov_iter *from);
void sctp_chunk_free(struct sctp_chunk *);
void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
struct sctp_chunk *sctp_chunkify(struct sk_buff *,
				 const struct sctp_association *,
				 struct sock *, gfp_t gfp);
void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
		     union sctp_addr *);
const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);

enum {
	SCTP_ADDR_NEW,		/* new address added to assoc/ep */
	SCTP_ADDR_SRC,		/* address can be used as source */
	SCTP_ADDR_DEL,		/* address about to be deleted */
};

/* This is a structure for holding either an IPv6 or an IPv4 address.  */
struct sctp_sockaddr_entry {
	struct list_head list;
	struct rcu_head	rcu;
	union sctp_addr a;
	__u8 state;
	__u8 valid;
};

#define SCTP_ADDRESS_TICK_DELAY	500

typedef struct sctp_chunk *(sctp_packet_phandler_t)(struct sctp_association *);

/* This structure holds lists of chunks as we are assembling for
 * transmission.
 */
struct sctp_packet {
	/* These are the SCTP header values (host order) for the packet. */
	__u16 source_port;
	__u16 destination_port;
	__u32 vtag;

	/* This contains the payload chunks.  */
	struct list_head chunk_list;

	/* This is the overhead of the sctp and ip headers. */
	size_t overhead;
	/* This is the total size of all chunks INCLUDING padding.  */
	size_t size;
	/* This is the maximum size this packet may have */
	size_t max_size;

	/* The packet is destined for this transport address.
	 * The function we finally use to pass down to the next lower
	 * layer lives in the transport structure.
	 */
	struct sctp_transport *transport;

	/* pointer to the auth chunk for this packet */
	struct sctp_chunk *auth;

	u8  has_cookie_echo:1,	/* This packet contains a COOKIE-ECHO chunk. */
	    has_sack:1,		/* This packet contains a SACK chunk. */
	    has_auth:1,		/* This packet contains an AUTH chunk */
	    has_data:1,		/* This packet contains at least 1 DATA chunk */
	    ipfragok:1;		/* So let ip fragment this packet */
};

struct sctp_packet *sctp_packet_init(struct sctp_packet *,
				     struct sctp_transport *,
				     __u16 sport, __u16 dport);
struct sctp_packet *sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
sctp_xmit_t sctp_packet_transmit_chunk(struct sctp_packet *,
				       struct sctp_chunk *, int, gfp_t);
sctp_xmit_t sctp_packet_append_chunk(struct sctp_packet *,
                                     struct sctp_chunk *);
int sctp_packet_transmit(struct sctp_packet *, gfp_t);
void sctp_packet_free(struct sctp_packet *);

static inline int sctp_packet_empty(struct sctp_packet *packet)
{
	return packet->size == packet->overhead;
}

/* This represents a remote transport address.
 * For local transport addresses, we just use union sctp_addr.
 *
 * RFC2960 Section 1.4 Key Terms
 *
 *   o	Transport address:  A Transport Address is traditionally defined
 *	by Network Layer address, Transport Layer protocol and Transport
 *	Layer port number.  In the case of SCTP running over IP, a
 *	transport address is defined by the combination of an IP address
 *	and an SCTP port number (where SCTP is the Transport protocol).
 *
 * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
 *
 *   o	The sender keeps a separate congestion control parameter set for
 *	each of the destination addresses it can send to (not each
 *	source-destination pair but for each destination).  The parameters
 *	should decay if the address is not used for a long enough time
 *	period.
 *
 */
struct sctp_transport {
	/* A list of transports. */
	struct list_head transports;
	struct rhash_head node;

	/* Reference counting. */
	atomic_t refcnt;
		/* RTO-Pending : A flag used to track if one of the DATA
		 *		chunks sent to this address is currently being
		 *		used to compute a RTT. If this flag is 0,
		 *		the next DATA chunk sent to this destination
		 *		should be used to compute a RTT and this flag
		 *		should be set. Every time the RTT
		 *		calculation completes (i.e. the DATA chunk
		 *		is SACK'd) clear this flag.
		 */
	__u32	rto_pending:1,

		/*
		 * hb_sent : a flag that signals that we have a pending
		 * heartbeat.
		 */
		hb_sent:1,

		/* Is the Path MTU update pending on this tranport */
		pmtu_pending:1,

		/* Has this transport moved the ctsn since we last sacked */
		sack_generation:1;
	u32 dst_cookie;

	struct flowi fl;

	/* This is the peer's IP address and port. */
	union sctp_addr ipaddr;

	/* These are the functions we call to handle LLP stuff.	 */
	struct sctp_af *af_specific;

	/* Which association do we belong to?  */
	struct sctp_association *asoc;

	/* RFC2960
	 *
	 * 12.3 Per Transport Address Data
	 *
	 * For each destination transport address in the peer's
	 * address list derived from the INIT or INIT ACK chunk, a
	 * number of data elements needs to be maintained including:
	 */
	/* RTO	       : The current retransmission timeout value.  */
	unsigned long rto;

	__u32 rtt;		/* This is the most recent RTT.	 */

	/* RTTVAR      : The current RTT variation.  */
	__u32 rttvar;

	/* SRTT	       : The current smoothed round trip time.	*/
	__u32 srtt;

	/*
	 * These are the congestion stats.
	 */
	/* cwnd	       : The current congestion window.	 */
	__u32 cwnd;		  /* This is the actual cwnd.  */

	/* ssthresh    : The current slow start threshold value.  */
	__u32 ssthresh;

	/* partial     : The tracking method for increase of cwnd when in
	 * bytes acked : congestion avoidance mode (see Section 6.2.2)
	 */
	__u32 partial_bytes_acked;

	/* Data that has been sent, but not acknowledged. */
	__u32 flight_size;

	__u32 burst_limited;	/* Holds old cwnd when max.burst is applied */

	/* Destination */
	struct dst_entry *dst;
	/* Source address. */
	union sctp_addr saddr;

	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
	 * the destination address every heartbeat interval.
	 */
	unsigned long hbinterval;

	/* SACK delay timeout */
	unsigned long sackdelay;
	__u32 sackfreq;

	/* When was the last time that we heard from this transport? We use
	 * this to pick new active and retran paths.
	 */
	ktime_t last_time_heard;

	/* When was the last time that we sent a chunk using this
	 * transport? We use this to check for idle transports
	 */
	unsigned long last_time_sent;

	/* Last time(in jiffies) when cwnd is reduced due to the congestion
	 * indication based on ECNE chunk.
	 */
	unsigned long last_time_ecne_reduced;

	/* This is the max_retrans value for the transport and will
	 * be initialized from the assocs value.  This can be changed
	 * using the SCTP_SET_PEER_ADDR_PARAMS socket option.
	 */
	__u16 pathmaxrxt;

	/* This is the partially failed retrans value for the transport
	 * and will be initialized from the assocs value.  This can be changed
	 * using the SCTP_PEER_ADDR_THLDS socket option
	 */
	int pf_retrans;
	/* PMTU	      : The current known path MTU.  */
	__u32 pathmtu;

	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
	__u32 param_flags;

	/* The number of times INIT has been sent on this transport. */
	int init_sent_count;

	/* state       : The current state of this destination,
	 *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
	 */
	int state;

	/* These are the error stats for this destination.  */

	/* Error count : The current error count for this destination.	*/
	unsigned short error_count;

	/* Per	       : A timer used by each destination.
	 * Destination :
	 * Timer       :
	 *
	 * [Everywhere else in the text this is called T3-rtx. -ed]
	 */
	struct timer_list T3_rtx_timer;

	/* Heartbeat timer is per destination. */
	struct timer_list hb_timer;

	/* Timer to handle ICMP proto unreachable envets */
	struct timer_list proto_unreach_timer;

	/* Since we're using per-destination retransmission timers
	 * (see above), we're also using per-destination "transmitted"
	 * queues.  This probably ought to be a private struct
	 * accessible only within the outqueue, but it's not, yet.
	 */
	struct list_head transmitted;

	/* We build bundle-able packets for this transport here.  */
	struct sctp_packet packet;

	/* This is the list of transports that have chunks to send.  */
	struct list_head send_ready;

	/* State information saved for SFR_CACC algorithm. The key
	 * idea in SFR_CACC is to maintain state at the sender on a
	 * per-destination basis when a changeover happens.
	 *	char changeover_active;
	 *	char cycling_changeover;
	 *	__u32 next_tsn_at_change;
	 *	char cacc_saw_newack;
	 */
	struct {
		/* An unsigned integer, which stores the next TSN to be
		 * used by the sender, at the moment of changeover.
		 */
		__u32 next_tsn_at_change;

		/* A flag which indicates the occurrence of a changeover */
		char changeover_active;

		/* A flag which indicates whether the change of primary is
		 * the first switch to this destination address during an
		 * active switch.
		 */
		char cycling_changeover;

		/* A temporary flag, which is used during the processing of
		 * a SACK to estimate the causative TSN(s)'s group.
		 */
		char cacc_saw_newack;
	} cacc;

	/* 64-bit random number sent with heartbeat. */
	__u64 hb_nonce;

	struct rcu_head rcu;
};

struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
					  gfp_t);
void sctp_transport_set_owner(struct sctp_transport *,
			      struct sctp_association *);
void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
			  struct sctp_sock *);
void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
void sctp_transport_free(struct sctp_transport *);
void sctp_transport_reset_t3_rtx(struct sctp_transport *);
void sctp_transport_reset_hb_timer(struct sctp_transport *);
int sctp_transport_hold(struct sctp_transport *);
void sctp_transport_put(struct sctp_transport *);
void sctp_transport_update_rto(struct sctp_transport *, __u32);
void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
void sctp_transport_lower_cwnd(struct sctp_transport *, sctp_lower_cwnd_t);
void sctp_transport_burst_limited(struct sctp_transport *);
void sctp_transport_burst_reset(struct sctp_transport *);
unsigned long sctp_transport_timeout(struct sctp_transport *);
void sctp_transport_reset(struct sctp_transport *);
void sctp_transport_update_pmtu(struct sock *, struct sctp_transport *, u32);
void sctp_transport_immediate_rtx(struct sctp_transport *);


/* This is the structure we use to queue packets as they come into
 * SCTP.  We write packets to it and read chunks from it.
 */
struct sctp_inq {
	/* This is actually a queue of sctp_chunk each
	 * containing a partially decoded packet.
	 */
	struct list_head in_chunk_list;
	/* This is the packet which is currently off the in queue and is
	 * being worked on through the inbound chunk processing.
	 */
	struct sctp_chunk *in_progress;

	/* This is the delayed task to finish delivering inbound
	 * messages.
	 */
	struct work_struct immediate;
};

void sctp_inq_init(struct sctp_inq *);
void sctp_inq_free(struct sctp_inq *);
void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);

/* This is the structure we use to hold outbound chunks.  You push
 * chunks in and they automatically pop out the other end as bundled
 * packets (it calls (*output_handler)()).
 *
 * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
 * and 8.2 of the v13 draft.
 *
 * It handles retransmissions.	The connection to the timeout portion
 * of the state machine is through sctp_..._timeout() and timeout_handler.
 *
 * If you feed it SACKs, it will eat them.
 *
 * If you give it big chunks, it will fragment them.
 *
 * It assigns TSN's to data chunks.  This happens at the last possible
 * instant before transmission.
 *
 * When free()'d, it empties itself out via output_handler().
 */
struct sctp_outq {
	struct sctp_association *asoc;

	/* Data pending that has never been transmitted.  */
	struct list_head out_chunk_list;

	unsigned int out_qlen;	/* Total length of queued data chunks. */

	/* Error of send failed, may used in SCTP_SEND_FAILED event. */
	unsigned int error;

	/* These are control chunks we want to send.  */
	struct list_head control_chunk_list;

	/* These are chunks that have been sacked but are above the
	 * CTSN, or cumulative tsn ack point.
	 */
	struct list_head sacked;

	/* Put chunks on this list to schedule them for
	 * retransmission.
	 */
	struct list_head retransmit;

	/* Put chunks on this list to save them for FWD TSN processing as
	 * they were abandoned.
	 */
	struct list_head abandoned;

	/* How many unackd bytes do we have in-flight?	*/
	__u32 outstanding_bytes;

	/* Are we doing fast-rtx on this queue */
	char fast_rtx;

	/* Corked? */
	char cork;
};

void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
void sctp_outq_teardown(struct sctp_outq *);
void sctp_outq_free(struct sctp_outq*);
int sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk, gfp_t);
int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
int sctp_outq_is_empty(const struct sctp_outq *);
void sctp_outq_restart(struct sctp_outq *);

void sctp_retransmit(struct sctp_outq *, struct sctp_transport *,
		     sctp_retransmit_reason_t);
void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
int sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
void sctp_prsctp_prune(struct sctp_association *asoc,
		       struct sctp_sndrcvinfo *sinfo, int msg_len);
/* Uncork and flush an outqueue.  */
static inline void sctp_outq_cork(struct sctp_outq *q)
{
	q->cork = 1;
}

/* SCTP skb control block.
 * sctp_input_cb is currently used on rx and sock rx queue
 */
struct sctp_input_cb {
	union {
		struct inet_skb_parm	h4;
#if IS_ENABLED(CONFIG_IPV6)
		struct inet6_skb_parm	h6;
#endif
	} header;
	struct sctp_chunk *chunk;
	struct sctp_af *af;
};
#define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))

static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
{
	const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;

	return chunk->head_skb ? : skb;
}

/* These bind address data fields common between endpoints and associations */
struct sctp_bind_addr {

	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
	 *
	 * SCTP Port:	The local SCTP port number the endpoint is
	 *		bound to.
	 */
	__u16 port;

	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
	 *
	 * Address List: The list of IP addresses that this instance
	 *	has bound.  This information is passed to one's
	 *	peer(s) in INIT and INIT ACK chunks.
	 */
	struct list_head address_list;
};

void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
void sctp_bind_addr_free(struct sctp_bind_addr *);
int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
			const struct sctp_bind_addr *src,
			sctp_scope_t scope, gfp_t gfp,
			int flags);
int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
			const struct sctp_bind_addr *src,
			gfp_t gfp);
int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
		       int new_size, __u8 addr_state, gfp_t gfp);
int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
			 struct sctp_sock *);
int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
			 struct sctp_sock *, struct sctp_sock *);
int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
			 const union sctp_addr *addr);
union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
					const union sctp_addr	*addrs,
					int			addrcnt,
					struct sctp_sock	*opt);
union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
					 int *addrs_len,
					 gfp_t gfp);
int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
			   __u16 port, gfp_t gfp);

sctp_scope_t sctp_scope(const union sctp_addr *);
int sctp_in_scope(struct net *net, const union sctp_addr *addr, const sctp_scope_t scope);
int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
int sctp_is_ep_boundall(struct sock *sk);


/* What type of endpoint?  */
typedef enum {
	SCTP_EP_TYPE_SOCKET,
	SCTP_EP_TYPE_ASSOCIATION,
} sctp_endpoint_type_t;

/*
 * A common base class to bridge the implmentation view of a
 * socket (usually listening) endpoint versus an association's
 * local endpoint.
 * This common structure is useful for several purposes:
 *   1) Common interface for lookup routines.
 *	a) Subfunctions work for either endpoint or association
 *	b) Single interface to lookup allows hiding the lookup lock rather
 *	   than acquiring it externally.
 *   2) Common interface for the inbound chunk handling/state machine.
 *   3) Common object handling routines for reference counting, etc.
 *   4) Disentangle association lookup from endpoint lookup, where we
 *	do not have to find our endpoint to find our association.
 *
 */

struct sctp_ep_common {
	/* Fields to help us manage our entries in the hash tables. */
	struct hlist_node node;
	int hashent;

	/* Runtime type information.  What kind of endpoint is this? */
	sctp_endpoint_type_t type;

	/* Some fields to help us manage this object.
	 *   refcnt   - Reference count access to this object.
	 *   dead     - Do not attempt to use this object.
	 */
	atomic_t    refcnt;
	bool	    dead;

	/* What socket does this endpoint belong to?  */
	struct sock *sk;

	/* This is where we receive inbound chunks.  */
	struct sctp_inq	  inqueue;

	/* This substructure includes the defining parameters of the
	 * endpoint:
	 * bind_addr.port is our shared port number.
	 * bind_addr.address_list is our set of local IP addresses.
	 */
	struct sctp_bind_addr bind_addr;
};


/* RFC Section 1.4 Key Terms
 *
 * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
 *   multi-homed host, an SCTP endpoint is represented to its peers as a
 *   combination of a set of eligible destination transport addresses to
 *   which SCTP packets can be sent and a set of eligible source
 *   transport addresses from which SCTP packets can be received.
 *   All transport addresses used by an SCTP endpoint must use the
 *   same port number, but can use multiple IP addresses. A transport
 *   address used by an SCTP endpoint must not be used by another
 *   SCTP endpoint. In other words, a transport address is unique
 *   to an SCTP endpoint.
 *
 * From an implementation perspective, each socket has one of these.
 * A TCP-style socket will have exactly one association on one of
 * these.  An UDP-style socket will have multiple associations hanging
 * off one of these.
 */

struct sctp_endpoint {
	/* Common substructure for endpoint and association. */
	struct sctp_ep_common base;

	/* Associations: A list of current associations and mappings
	 *	      to the data consumers for each association. This
	 *	      may be in the form of a hash table or other
	 *	      implementation dependent structure. The data
	 *	      consumers may be process identification
	 *	      information such as file descriptors, named pipe
	 *	      pointer, or table pointers dependent on how SCTP
	 *	      is implemented.
	 */
	/* This is really a list of struct sctp_association entries. */
	struct list_head asocs;

	/* Secret Key: A secret key used by this endpoint to compute
	 *	      the MAC.	This SHOULD be a cryptographic quality
	 *	      random number with a sufficient length.
	 *	      Discussion in [RFC1750] can be helpful in
	 *	      selection of the key.
	 */
	__u8 secret_key[SCTP_SECRET_SIZE];

 	/* digest:  This is a digest of the sctp cookie.  This field is
 	 * 	    only used on the receive path when we try to validate
 	 * 	    that the cookie has not been tampered with.  We put
 	 * 	    this here so we pre-allocate this once and can re-use
 	 * 	    on every receive.
 	 */
 	__u8 *digest;
 
	/* sendbuf acct. policy.	*/
	__u32 sndbuf_policy;

	/* rcvbuf acct. policy.	*/
	__u32 rcvbuf_policy;

	/* SCTP AUTH: array of the HMACs that will be allocated
	 * we need this per association so that we don't serialize
	 */
	struct crypto_shash **auth_hmacs;

	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
	 struct sctp_hmac_algo_param *auth_hmacs_list;

	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
	struct sctp_chunks_param *auth_chunk_list;

	/* SCTP-AUTH: endpoint shared keys */
	struct list_head endpoint_shared_keys;
	__u16 active_key_id;
	__u8  auth_enable:1,
	      prsctp_enable:1;
};

/* Recover the outter endpoint structure. */
static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
{
	struct sctp_endpoint *ep;

	ep = container_of(base, struct sctp_endpoint, base);
	return ep;
}

/* These are function signatures for manipulating endpoints.  */
struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
void sctp_endpoint_free(struct sctp_endpoint *);
void sctp_endpoint_put(struct sctp_endpoint *);
void sctp_endpoint_hold(struct sctp_endpoint *);
void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
struct sctp_association *sctp_endpoint_lookup_assoc(
	const struct sctp_endpoint *ep,
	const union sctp_addr *paddr,
	struct sctp_transport **);
int sctp_endpoint_is_peeled_off(struct sctp_endpoint *,
				const union sctp_addr *);
struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
					struct net *, const union sctp_addr *);
int sctp_has_association(struct net *net, const union sctp_addr *laddr,
			 const union sctp_addr *paddr);

int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
		     const struct sctp_association *asoc,
		     sctp_cid_t, sctp_init_chunk_t *peer_init,
		     struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
		      const union sctp_addr *peer,
		      sctp_init_chunk_t *init, gfp_t gfp);
__u32 sctp_generate_tag(const struct sctp_endpoint *);
__u32 sctp_generate_tsn(const struct sctp_endpoint *);

struct sctp_inithdr_host {
	__u32 init_tag;
	__u32 a_rwnd;
	__u16 num_outbound_streams;
	__u16 num_inbound_streams;
	__u32 initial_tsn;
};

/* SCTP_GET_ASSOC_STATS counters */
struct sctp_priv_assoc_stats {
	/* Maximum observed rto in the association during subsequent
	 * observations. Value is set to 0 if no RTO measurement took place
	 * The transport where the max_rto was observed is returned in
	 * obs_rto_ipaddr
	 */
	struct sockaddr_storage obs_rto_ipaddr;
	__u64 max_obs_rto;
	/* Total In and Out SACKs received and sent */
	__u64 isacks;
	__u64 osacks;
	/* Total In and Out packets received and sent */
	__u64 opackets;
	__u64 ipackets;
	/* Total retransmitted chunks */
	__u64 rtxchunks;
	/* TSN received > next expected */
	__u64 outofseqtsns;
	/* Duplicate Chunks received */
	__u64 idupchunks;
	/* Gap Ack Blocks received */
	__u64 gapcnt;
	/* Unordered data chunks sent and received */
	__u64 ouodchunks;
	__u64 iuodchunks;
	/* Ordered data chunks sent and received */
	__u64 oodchunks;
	__u64 iodchunks;
	/* Control chunks sent and received */
	__u64 octrlchunks;
	__u64 ictrlchunks;
};

/* RFC2960
 *
 * 12. Recommended Transmission Control Block (TCB) Parameters
 *
 * This section details a recommended set of parameters that should
 * be contained within the TCB for an implementation. This section is
 * for illustrative purposes and should not be deemed as requirements
 * on an implementation or as an exhaustive list of all parameters
 * inside an SCTP TCB. Each implementation may need its own additional
 * parameters for optimization.
 */


/* Here we have information about each individual association. */
struct sctp_association {

	/* A base structure common to endpoint and association.
	 * In this context, it represents the associations's view
	 * of the local endpoint of the association.
	 */
	struct sctp_ep_common base;

	/* Associations on the same socket. */
	struct list_head asocs;

	/* association id. */
	sctp_assoc_t assoc_id;

	/* This is our parent endpoint.	 */
	struct sctp_endpoint *ep;

	/* These are those association elements needed in the cookie.  */
	struct sctp_cookie c;

	/* This is all information about our peer.  */
	struct {
		/* transport_addr_list
		 *
		 * Peer	       : A list of SCTP transport addresses that the
		 * Transport   : peer is bound to. This information is derived
		 * Address     : from the INIT or INIT ACK and is used to
		 * List	       : associate an inbound packet with a given
		 *	       : association. Normally this information is
		 *	       : hashed or keyed for quick lookup and access
		 *	       : of the TCB.
		 *	       : The list is also initialized with the list
		 *	       : of addresses passed with the sctp_connectx()
		 *	       : call.
		 *
		 * It is a list of SCTP_transport's.
		 */
		struct list_head transport_addr_list;

		/* rwnd
		 *
		 * Peer Rwnd   : Current calculated value of the peer's rwnd.
		 */
		__u32 rwnd;

		/* transport_count
		 *
		 * Peer        : A count of the number of peer addresses
		 * Transport   : in the Peer Transport Address List.
		 * Address     :
		 * Count       :
		 */
		__u16 transport_count;

		/* port
		 *   The transport layer port number.
		 */
		__u16 port;

		/* primary_path
		 *
		 * Primary     : This is the current primary destination
		 * Path	       : transport address of the peer endpoint.  It
		 *	       : may also specify a source transport address
		 *	       : on this endpoint.
		 *
		 * All of these paths live on transport_addr_list.
		 *
		 * At the bakeoffs, we discovered that the intent of
		 * primaryPath is that it only changes when the ULP
		 * asks to have it changed.  We add the activePath to
		 * designate the connection we are currently using to
		 * transmit new data and most control chunks.
		 */
		struct sctp_transport *primary_path;

		/* Cache the primary path address here, when we
		 * need a an address for msg_name.
		 */
		union sctp_addr primary_addr;

		/* active_path
		 *   The path that we are currently using to
		 *   transmit new data and most control chunks.
		 */
		struct sctp_transport *active_path;

		/* retran_path
		 *
		 * RFC2960 6.4 Multi-homed SCTP Endpoints
		 * ...
		 * Furthermore, when its peer is multi-homed, an
		 * endpoint SHOULD try to retransmit a chunk to an
		 * active destination transport address that is
		 * different from the last destination address to
		 * which the DATA chunk was sent.
		 */
		struct sctp_transport *retran_path;

		/* Pointer to last transport I have sent on.  */
		struct sctp_transport *last_sent_to;

		/* This is the last transport I have received DATA on.	*/
		struct sctp_transport *last_data_from;

		/*
		 * Mapping  An array of bits or bytes indicating which out of
		 * Array    order TSN's have been received (relative to the
		 *	    Last Rcvd TSN). If no gaps exist, i.e. no out of
		 *	    order packets have been received, this array
		 *	    will be set to all zero. This structure may be
		 *	    in the form of a circular buffer or bit array.
		 *
		 * Last Rcvd   : This is the last TSN received in
		 * TSN	       : sequence. This value is set initially by
		 *	       : taking the peer's Initial TSN, received in
		 *	       : the INIT or INIT ACK chunk, and subtracting
		 *	       : one from it.
		 *
		 * Throughout most of the specification this is called the
		 * "Cumulative TSN ACK Point".	In this case, we
		 * ignore the advice in 12.2 in favour of the term
		 * used in the bulk of the text.  This value is hidden
		 * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
		 */
		struct sctp_tsnmap tsn_map;

		/* This mask is used to disable sending the ASCONF chunk
		 * with specified parameter to peer.
		 */
		__be16 addip_disabled_mask;

		/* These are capabilities which our peer advertised.  */
		__u8	ecn_capable:1,      /* Can peer do ECN? */
			ipv4_address:1,     /* Peer understands IPv4 addresses? */
			ipv6_address:1,     /* Peer understands IPv6 addresses? */
			hostname_address:1, /* Peer understands DNS addresses? */
			asconf_capable:1,   /* Does peer support ADDIP? */
			prsctp_capable:1,   /* Can peer do PR-SCTP? */
			auth_capable:1;     /* Is peer doing SCTP-AUTH? */

		/* sack_needed : This flag indicates if the next received
		 *             : packet is to be responded to with a
		 *             : SACK. This is initialized to 0.  When a packet
		 *             : is received sack_cnt is incremented. If this value
		 *             : reaches 2 or more, a SACK is sent and the
		 *             : value is reset to 0. Note: This is used only
		 *             : when no DATA chunks are received out of
		 *             : order.  When DATA chunks are out of order,
		 *             : SACK's are not delayed (see Section 6).
		 */
		__u8    sack_needed:1,     /* Do we need to sack the peer? */
			sack_generation:1,
			zero_window_announced:1;
		__u32	sack_cnt;

		__u32   adaptation_ind;	 /* Adaptation Code point. */

		struct sctp_inithdr_host i;
		void *cookie;
		int cookie_len;

		/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
		 * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
		 * Initial TSN Value minus 1
		 */
		__u32 addip_serial;

		/* SCTP-AUTH: We need to know pears random number, hmac list
		 * and authenticated chunk list.  All that is part of the
		 * cookie and these are just pointers to those locations
		 */
		sctp_random_param_t *peer_random;
		sctp_chunks_param_t *peer_chunks;
		sctp_hmac_algo_param_t *peer_hmacs;
	} peer;

	/* State       : A state variable indicating what state the
	 *	       : association is in, i.e. COOKIE-WAIT,
	 *	       : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
	 *	       : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
	 *
	 *		Note: No "CLOSED" state is illustrated since if a
	 *		association is "CLOSED" its TCB SHOULD be removed.
	 *
	 *		In this implementation we DO have a CLOSED
	 *		state which is used during initiation and shutdown.
	 *
	 *		State takes values from SCTP_STATE_*.
	 */
	sctp_state_t state;

	/* Overall     : The overall association error count.
	 * Error Count : [Clear this any time I get something.]
	 */
	int overall_error_count;

	/* The cookie life I award for any cookie.  */
	ktime_t cookie_life;

	/* These are the association's initial, max, and min RTO values.
	 * These values will be initialized by system defaults, but can
	 * be modified via the SCTP_RTOINFO socket option.
	 */
	unsigned long rto_initial;
	unsigned long rto_max;
	unsigned long rto_min;

	/* Maximum number of new data packets that can be sent in a burst.  */
	int max_burst;

	/* This is the max_retrans value for the association.  This value will
	 * be initialized initialized from system defaults, but can be
	 * modified by the SCTP_ASSOCINFO socket option.
	 */
	int max_retrans;

	/* This is the partially failed retrans value for the transport
	 * and will be initialized from the assocs value.  This can be
	 * changed using the SCTP_PEER_ADDR_THLDS socket option
	 */
	int pf_retrans;

	/* Maximum number of times the endpoint will retransmit INIT  */
	__u16 max_init_attempts;

	/* How many times have we resent an INIT? */
	__u16 init_retries;

	/* The largest timeout or RTO value to use in attempting an INIT */
	unsigned long max_init_timeo;

	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
	 * the destination address every heartbeat interval. This value
	 * will be inherited by all new transports.
	 */
	unsigned long hbinterval;

	/* This is the max_retrans value for new transports in the
	 * association.
	 */
	__u16 pathmaxrxt;

	/* Flag that path mtu update is pending */
	__u8   pmtu_pending;

	/* Association : The smallest PMTU discovered for all of the
	 * PMTU	       : peer's transport addresses.
	 */
	__u32 pathmtu;

	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
	__u32 param_flags;

	__u32 sackfreq;
	/* SACK delay timeout */
	unsigned long sackdelay;

	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];

	/* Transport to which SHUTDOWN chunk was last sent.  */
	struct sctp_transport *shutdown_last_sent_to;

	/* Transport to which INIT chunk was last sent.  */
	struct sctp_transport *init_last_sent_to;

	/* How many times have we resent a SHUTDOWN */
	int shutdown_retries;

	/* Next TSN    : The next TSN number to be assigned to a new
	 *	       : DATA chunk.  This is sent in the INIT or INIT
	 *	       : ACK chunk to the peer and incremented each
	 *	       : time a DATA chunk is assigned a TSN
	 *	       : (normally just prior to transmit or during
	 *	       : fragmentation).
	 */
	__u32 next_tsn;

	/*
	 * Last Rcvd   : This is the last TSN received in sequence.  This value
	 * TSN	       : is set initially by taking the peer's Initial TSN,
	 *	       : received in the INIT or INIT ACK chunk, and
	 *	       : subtracting one from it.
	 *
	 * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
	 */

	__u32 ctsn_ack_point;

	/* PR-SCTP Advanced.Peer.Ack.Point */
	__u32 adv_peer_ack_point;

	/* Highest TSN that is acknowledged by incoming SACKs. */
	__u32 highest_sacked;

	/* TSN marking the fast recovery exit point */
	__u32 fast_recovery_exit;

	/* Flag to track the current fast recovery state */
	__u8 fast_recovery;

	/* The number of unacknowledged data chunks.  Reported through
	 * the SCTP_STATUS sockopt.
	 */
	__u16 unack_data;

	/* The total number of data chunks that we've had to retransmit
	 * as the result of a T3 timer expiration
	 */
	__u32 rtx_data_chunks;

	/* This is the association's receive buffer space.  This value is used
	 * to set a_rwnd field in an INIT or a SACK chunk.
	 */
	__u32 rwnd;

	/* This is the last advertised value of rwnd over a SACK chunk. */
	__u32 a_rwnd;

	/* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
	 * to slop over a maximum of the association's frag_point.
	 */
	__u32 rwnd_over;

	/* Keeps treack of rwnd pressure.  This happens when we have
	 * a window, but not recevie buffer (i.e small packets).  This one
	 * is releases slowly (1 PMTU at a time ).
	 */
	__u32 rwnd_press;

	/* This is the sndbuf size in use for the association.
	 * This corresponds to the sndbuf size for the association,
	 * as specified in the sk->sndbuf.
	 */
	int sndbuf_used;

	/* This is the amount of memory that this association has allocated
	 * in the receive path at any given time.
	 */
	atomic_t rmem_alloc;

	/* This is the wait queue head for send requests waiting on
	 * the association sndbuf space.
	 */
	wait_queue_head_t	wait;

	/* The message size at which SCTP fragmentation will occur. */
	__u32 frag_point;
	__u32 user_frag;

	/* Counter used to count INIT errors. */
	int init_err_counter;

	/* Count the number of INIT cycles (for doubling timeout). */
	int init_cycle;

	/* Default send parameters. */
	__u16 default_stream;
	__u16 default_flags;
	__u32 default_ppid;
	__u32 default_context;
	__u32 default_timetolive;

	/* Default receive parameters */
	__u32 default_rcv_context;

	/* This tracks outbound ssn for a given stream.	 */
	struct sctp_ssnmap *ssnmap;

	/* All outbound chunks go through this structure.  */
	struct sctp_outq outqueue;

	/* A smart pipe that will handle reordering and fragmentation,
	 * as well as handle passing events up to the ULP.
	 */
	struct sctp_ulpq ulpq;

	/* Last TSN that caused an ECNE Chunk to be sent.  */
	__u32 last_ecne_tsn;

	/* Last TSN that caused a CWR Chunk to be sent.	 */
	__u32 last_cwr_tsn;

	/* How many duplicated TSNs have we seen?  */
	int numduptsns;

	/* These are to support
	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
	 *  and Enforcement of Flow and Message Limits"
	 * <draft-ietf-tsvwg-addip-sctp-02.txt>
	 * or "ADDIP" for short.
	 */



	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
	 *
	 * R1) One and only one ASCONF Chunk MAY be in transit and
	 * unacknowledged at any one time.  If a sender, after sending
	 * an ASCONF chunk, decides it needs to transfer another
	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
	 * returns from the previous ASCONF Chunk before sending a
	 * subsequent ASCONF. Note this restriction binds each side,
	 * so at any time two ASCONF may be in-transit on any given
	 * association (one sent from each endpoint).
	 *
	 * [This is our one-and-only-one ASCONF in flight.  If we do
	 * not have an ASCONF in flight, this is NULL.]
	 */
	struct sctp_chunk *addip_last_asconf;

	/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
	 *
	 * This is needed to implement itmes E1 - E4 of the updated
	 * spec.  Here is the justification:
	 *
	 * Since the peer may bundle multiple ASCONF chunks toward us,
	 * we now need the ability to cache multiple ACKs.  The section
	 * describes in detail how they are cached and cleaned up.
	 */
	struct list_head asconf_ack_list;

	/* These ASCONF chunks are waiting to be sent.
	 *
	 * These chunaks can't be pushed to outqueue until receiving
	 * ASCONF_ACK for the previous ASCONF indicated by
	 * addip_last_asconf, so as to guarantee that only one ASCONF
	 * is in flight at any time.
	 *
	 * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
	 *
	 * In defining the ASCONF Chunk transfer procedures, it is
	 * essential that these transfers MUST NOT cause congestion
	 * within the network.	To achieve this, we place these
	 * restrictions on the transfer of ASCONF Chunks:
	 *
	 * R1) One and only one ASCONF Chunk MAY be in transit and
	 * unacknowledged at any one time.  If a sender, after sending
	 * an ASCONF chunk, decides it needs to transfer another
	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
	 * returns from the previous ASCONF Chunk before sending a
	 * subsequent ASCONF. Note this restriction binds each side,
	 * so at any time two ASCONF may be in-transit on any given
	 * association (one sent from each endpoint).
	 *
	 *
	 * [I really think this is EXACTLY the sort of intelligence
	 *  which already resides in sctp_outq.	 Please move this
	 *  queue and its supporting logic down there.	--piggy]
	 */
	struct list_head addip_chunk_list;

	/* ADDIP Section 4.1 ASCONF Chunk Procedures
	 *
	 * A2) A serial number should be assigned to the Chunk. The
	 * serial number SHOULD be a monotonically increasing
	 * number. The serial number SHOULD be initialized at
	 * the start of the association to the same value as the
	 * Initial TSN and every time a new ASCONF chunk is created
	 * it is incremented by one after assigning the serial number
	 * to the newly created chunk.
	 *
	 * ADDIP
	 * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
	 *
	 * Serial Number : 32 bits (unsigned integer)
	 *
	 * This value represents a Serial Number for the ASCONF
	 * Chunk. The valid range of Serial Number is from 0 to
	 * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
	 * after reaching 4294967295.
	 */
	__u32 addip_serial;
	int src_out_of_asoc_ok;
	union sctp_addr *asconf_addr_del_pending;
	struct sctp_transport *new_transport;

	/* SCTP AUTH: list of the endpoint shared keys.  These
	 * keys are provided out of band by the user applicaton
	 * and can't change during the lifetime of the association
	 */
	struct list_head endpoint_shared_keys;

	/* SCTP AUTH:
	 * The current generated assocaition shared key (secret)
	 */
	struct sctp_auth_bytes *asoc_shared_key;

	/* SCTP AUTH: hmac id of the first peer requested algorithm
	 * that we support.
	 */
	__u16 default_hmac_id;

	__u16 active_key_id;

	__u8 need_ecne:1,	/* Need to send an ECNE Chunk? */
	     temp:1,		/* Is it a temporary association? */
	     prsctp_enable:1;

	struct sctp_priv_assoc_stats stats;

	int sent_cnt_removable;

	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
};


/* An eyecatcher for determining if we are really looking at an
 * association data structure.
 */
enum {
	SCTP_ASSOC_EYECATCHER = 0xa550c123,
};

/* Recover the outter association structure. */
static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
{
	struct sctp_association *asoc;

	asoc = container_of(base, struct sctp_association, base);
	return asoc;
}

/* These are function signatures for manipulating associations.	 */


struct sctp_association *
sctp_association_new(const struct sctp_endpoint *, const struct sock *,
		     sctp_scope_t scope, gfp_t gfp);
void sctp_association_free(struct sctp_association *);
void sctp_association_put(struct sctp_association *);
void sctp_association_hold(struct sctp_association *);

struct sctp_transport *sctp_assoc_choose_alter_transport(
	struct sctp_association *, struct sctp_transport *);
void sctp_assoc_update_retran_path(struct sctp_association *);
struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
					  const union sctp_addr *);
int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
			    const union sctp_addr *laddr);
struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
				     const union sctp_addr *address,
				     const gfp_t gfp,
				     const int peer_state);
void sctp_assoc_del_peer(struct sctp_association *asoc,
			 const union sctp_addr *addr);
void sctp_assoc_rm_peer(struct sctp_association *asoc,
			 struct sctp_transport *peer);
void sctp_assoc_control_transport(struct sctp_association *,
				  struct sctp_transport *,
				  sctp_transport_cmd_t, sctp_sn_error_t);
struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
struct sctp_transport *sctp_assoc_is_match(struct sctp_association *,
					   struct net *,
					   const union sctp_addr *,
					   const union sctp_addr *);
void sctp_assoc_migrate(struct sctp_association *, struct sock *);
void sctp_assoc_update(struct sctp_association *old,
		       struct sctp_association *new);

__u32 sctp_association_get_next_tsn(struct sctp_association *);

void sctp_assoc_sync_pmtu(struct sock *, struct sctp_association *);
void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
void sctp_assoc_set_primary(struct sctp_association *,
			    struct sctp_transport *);
void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
				    struct sctp_transport *);
int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *,
				     sctp_scope_t, gfp_t);
int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
					 struct sctp_cookie*,
					 gfp_t gfp);
int sctp_assoc_set_id(struct sctp_association *, gfp_t);
void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
					const struct sctp_association *asoc,
					__be32 serial);
void sctp_asconf_queue_teardown(struct sctp_association *asoc);

int sctp_cmp_addr_exact(const union sctp_addr *ss1,
			const union sctp_addr *ss2);
struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);

/* A convenience structure to parse out SCTP specific CMSGs. */
typedef struct sctp_cmsgs {
	struct sctp_initmsg *init;
	struct sctp_sndrcvinfo *srinfo;
	struct sctp_sndinfo *sinfo;
} sctp_cmsgs_t;

/* Structure for tracking memory objects */
typedef struct {
	char *label;
	atomic_t *counter;
} sctp_dbg_objcnt_entry_t;

#endif /* __sctp_structs_h__ */