include/linux/sctp.h

   1 /* SCTP kernel reference Implementation
   2  * (C) Copyright IBM Corp. 2001, 2004
   3  * Copyright (c) 1999-2000 Cisco, Inc.
   4  * Copyright (c) 1999-2001 Motorola, Inc.
   5  * Copyright (c) 2001 Intel Corp.
   6  * Copyright (c) 2001 Nokia, Inc.
   7  * Copyright (c) 2001 La Monte H.P. Yarroll
   8  *
   9  * This file is part of the SCTP kernel reference Implementation
  10  *
  11  * Various protocol defined structures.
  12  *
  13  * This SCTP implementation is free software;
  14  * you can redistribute it and/or modify it under the terms of
  15  * the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2, or (at your option)
  17  * any later version.
  18  *
  19  * This SCTP implementation is distributed in the hope that it
  20  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  21  *                 ************************
  22  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  23  * See the GNU General Public License for more details.
  24  *
  25  * You should have received a copy of the GNU General Public License
  26  * along with GNU CC; see the file COPYING.  If not, see
  27  * <http://www.gnu.org/licenses/>.
  28  *
  29  * Please send any bug reports or fixes you make to the
  30  * email address(es):
  31  *    lksctp developers <linux-sctp@vger.kernel.org>
  32  *
  33  * Or submit a bug report through the following website:
  34  *    http://www.sf.net/projects/lksctp
  35  *
  36  * Written or modified by:
  37  *    La Monte H.P. Yarroll <piggy@acm.org>
  38  *    Karl Knutson <karl@athena.chicago.il.us>
  39  *    Jon Grimm <jgrimm@us.ibm.com>
  40  *    Xingang Guo <xingang.guo@intel.com>
  41  *    randall@sctp.chicago.il.us
  42  *    kmorneau@cisco.com
  43  *    qxie1@email.mot.com
  44  *    Sridhar Samudrala <sri@us.ibm.com>
  45  *    Kevin Gao <kevin.gao@intel.com>
  46  *
  47  * Any bugs reported given to us we will try to fix... any fixes shared will
  48  * be incorporated into the next SCTP release.
  49  */
  50 #ifndef __LINUX_SCTP_H__
  51 #define __LINUX_SCTP_H__
  52
  53 #include <linux/in.h>           /* We need in_addr.  */
  54 #include <linux/in6.h>          /* We need in6_addr.  */
  55 #include <linux/skbuff.h>
  56
  57 #include <uapi/linux/sctp.h>
  58
  59 /* Section 3.1.  SCTP Common Header Format */
  60 typedef struct sctphdr {
  61         __be16 source;
  62         __be16 dest;
  63         __be32 vtag;
  64         __le32 checksum;
  65 } __packed sctp_sctphdr_t;
  66
  67 static inline struct sctphdr *sctp_hdr(const struct sk_buff *skb)
  68 {
  69         return (struct sctphdr *)skb_transport_header(skb);
  70 }
  71
  72 /* Section 3.2.  Chunk Field Descriptions. */
  73 typedef struct sctp_chunkhdr {
  74         __u8 type;
  75         __u8 flags;
  76         __be16 length;
  77 } __packed sctp_chunkhdr_t;
  78
  79
  80 /* Section 3.2.  Chunk Type Values.
  81  * [Chunk Type] identifies the type of information contained in the Chunk
  82  * Value field. It takes a value from 0 to 254. The value of 255 is
  83  * reserved for future use as an extension field.
  84  */
  85 typedef enum {
  86         SCTP_CID_DATA                   = 0,
  87         SCTP_CID_INIT                   = 1,
  88         SCTP_CID_INIT_ACK               = 2,
  89         SCTP_CID_SACK                   = 3,
  90         SCTP_CID_HEARTBEAT              = 4,
  91         SCTP_CID_HEARTBEAT_ACK          = 5,
  92         SCTP_CID_ABORT                  = 6,
  93         SCTP_CID_SHUTDOWN               = 7,
  94         SCTP_CID_SHUTDOWN_ACK           = 8,
  95         SCTP_CID_ERROR                  = 9,
  96         SCTP_CID_COOKIE_ECHO            = 10,
  97         SCTP_CID_COOKIE_ACK             = 11,
  98         SCTP_CID_ECN_ECNE               = 12,
  99         SCTP_CID_ECN_CWR                = 13,
 100         SCTP_CID_SHUTDOWN_COMPLETE      = 14,
 101
 102         /* AUTH Extension Section 4.1 */
 103         SCTP_CID_AUTH                   = 0x0F,
 104
 105         /* PR-SCTP Sec 3.2 */
 106         SCTP_CID_FWD_TSN                = 0xC0,
 107
 108         /* Use hex, as defined in ADDIP sec. 3.1 */
 109         SCTP_CID_ASCONF                 = 0xC1,
 110         SCTP_CID_ASCONF_ACK             = 0x80,
 111 } sctp_cid_t; /* enum */
 112
 113
 114 /* Section 3.2
 115  *  Chunk Types are encoded such that the highest-order two bits specify
 116  *  the action that must be taken if the processing endpoint does not
 117  *  recognize the Chunk Type.
 118  */
 119 typedef enum {
 120         SCTP_CID_ACTION_DISCARD     = 0x00,
 121         SCTP_CID_ACTION_DISCARD_ERR = 0x40,
 122         SCTP_CID_ACTION_SKIP        = 0x80,
 123         SCTP_CID_ACTION_SKIP_ERR    = 0xc0,
 124 } sctp_cid_action_t;
 125
 126 enum { SCTP_CID_ACTION_MASK = 0xc0, };
 127
 128 /* This flag is used in Chunk Flags for ABORT and SHUTDOWN COMPLETE.
 129  *
 130  * 3.3.7 Abort Association (ABORT) (6):
 131  *    The T bit is set to 0 if the sender had a TCB that it destroyed.
 132  *    If the sender did not have a TCB it should set this bit to 1.
 133  */
 134 enum { SCTP_CHUNK_FLAG_T = 0x01 };
 135
 136 /*
 137  *  Set the T bit
 138  *
 139  *      0                   1                   2                   3
 140  *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 141  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 142  *     |   Type = 14   |Reserved     |T|      Length = 4               |
 143  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 144  *
 145  * Chunk Flags: 8 bits
 146  *
 147  *   Reserved:  7 bits
 148  *     Set to 0 on transmit and ignored on receipt.
 149  *
 150  *   T bit:  1 bit
 151  *     The T bit is set to 0 if the sender had a TCB that it destroyed. If
 152  *     the sender did NOT have a TCB it should set this bit to 1.
 153  *
 154  * Note: Special rules apply to this chunk for verification, please
 155  * see Section 8.5.1 for details.
 156  */
 157
 158 #define sctp_test_T_bit(c)    ((c)->chunk_hdr->flags & SCTP_CHUNK_FLAG_T)
 159
 160 /* RFC 2960
 161  * Section 3.2.1 Optional/Variable-length Parmaeter Format.
 162  */
 163
 164 typedef struct sctp_paramhdr {
 165         __be16 type;
 166         __be16 length;
 167 } __packed sctp_paramhdr_t;
 168
 169 typedef enum {
 170
 171         /* RFC 2960 Section 3.3.5 */
 172         SCTP_PARAM_HEARTBEAT_INFO               = cpu_to_be16(1),
 173         /* RFC 2960 Section 3.3.2.1 */
 174         SCTP_PARAM_IPV4_ADDRESS                 = cpu_to_be16(5),
 175         SCTP_PARAM_IPV6_ADDRESS                 = cpu_to_be16(6),
 176         SCTP_PARAM_STATE_COOKIE                 = cpu_to_be16(7),
 177         SCTP_PARAM_UNRECOGNIZED_PARAMETERS      = cpu_to_be16(8),
 178         SCTP_PARAM_COOKIE_PRESERVATIVE          = cpu_to_be16(9),
 179         SCTP_PARAM_HOST_NAME_ADDRESS            = cpu_to_be16(11),
 180         SCTP_PARAM_SUPPORTED_ADDRESS_TYPES      = cpu_to_be16(12),
 181         SCTP_PARAM_ECN_CAPABLE                  = cpu_to_be16(0x8000),
 182
 183         /* AUTH Extension Section 3 */
 184         SCTP_PARAM_RANDOM                       = cpu_to_be16(0x8002),
 185         SCTP_PARAM_CHUNKS                       = cpu_to_be16(0x8003),
 186         SCTP_PARAM_HMAC_ALGO                    = cpu_to_be16(0x8004),
 187
 188         /* Add-IP: Supported Extensions, Section 4.2 */
 189         SCTP_PARAM_SUPPORTED_EXT        = cpu_to_be16(0x8008),
 190
 191         /* PR-SCTP Sec 3.1 */
 192         SCTP_PARAM_FWD_TSN_SUPPORT      = cpu_to_be16(0xc000),
 193
 194         /* Add-IP Extension. Section 3.2 */
 195         SCTP_PARAM_ADD_IP               = cpu_to_be16(0xc001),
 196         SCTP_PARAM_DEL_IP               = cpu_to_be16(0xc002),
 197         SCTP_PARAM_ERR_CAUSE            = cpu_to_be16(0xc003),
 198         SCTP_PARAM_SET_PRIMARY          = cpu_to_be16(0xc004),
 199         SCTP_PARAM_SUCCESS_REPORT       = cpu_to_be16(0xc005),
 200         SCTP_PARAM_ADAPTATION_LAYER_IND = cpu_to_be16(0xc006),
 201
 202 } sctp_param_t; /* enum */
 203
 204
 205 /* RFC 2960 Section 3.2.1
 206  *  The Parameter Types are encoded such that the highest-order two bits
 207  *  specify the action that must be taken if the processing endpoint does
 208  *  not recognize the Parameter Type.
 209  *
 210  */
 211 typedef enum {
 212         SCTP_PARAM_ACTION_DISCARD     = cpu_to_be16(0x0000),
 213         SCTP_PARAM_ACTION_DISCARD_ERR = cpu_to_be16(0x4000),
 214         SCTP_PARAM_ACTION_SKIP        = cpu_to_be16(0x8000),
 215         SCTP_PARAM_ACTION_SKIP_ERR    = cpu_to_be16(0xc000),
 216 } sctp_param_action_t;
 217
 218 enum { SCTP_PARAM_ACTION_MASK = cpu_to_be16(0xc000), };
 219
 220 /* RFC 2960 Section 3.3.1 Payload Data (DATA) (0) */
 221
 222 typedef struct sctp_datahdr {
 223         __be32 tsn;
 224         __be16 stream;
 225         __be16 ssn;
 226         __be32 ppid;
 227         __u8  payload[0];
 228 } __packed sctp_datahdr_t;
 229
 230 typedef struct sctp_data_chunk {
 231         sctp_chunkhdr_t chunk_hdr;
 232         sctp_datahdr_t  data_hdr;
 233 } __packed sctp_data_chunk_t;
 234
 235 /* DATA Chuck Specific Flags */
 236 enum {
 237         SCTP_DATA_MIDDLE_FRAG   = 0x00,
 238         SCTP_DATA_LAST_FRAG     = 0x01,
 239         SCTP_DATA_FIRST_FRAG    = 0x02,
 240         SCTP_DATA_NOT_FRAG      = 0x03,
 241         SCTP_DATA_UNORDERED     = 0x04,
 242         SCTP_DATA_SACK_IMM      = 0x08,
 243 };
 244 enum { SCTP_DATA_FRAG_MASK = 0x03, };
 245
 246
 247 /* RFC 2960 Section 3.3.2 Initiation (INIT) (1)
 248  *
 249  *  This chunk is used to initiate a SCTP association between two
 250  *  endpoints.
 251  */
 252 typedef struct sctp_inithdr {
 253         __be32 init_tag;
 254         __be32 a_rwnd;
 255         __be16 num_outbound_streams;
 256         __be16 num_inbound_streams;
 257         __be32 initial_tsn;
 258         __u8  params[0];
 259 } __packed sctp_inithdr_t;
 260
 261 typedef struct sctp_init_chunk {
 262         sctp_chunkhdr_t chunk_hdr;
 263         sctp_inithdr_t init_hdr;
 264 } __packed sctp_init_chunk_t;
 265
 266
 267 /* Section 3.3.2.1. IPv4 Address Parameter (5) */
 268 typedef struct sctp_ipv4addr_param {
 269         sctp_paramhdr_t param_hdr;
 270         struct in_addr  addr;
 271 } __packed sctp_ipv4addr_param_t;
 272
 273 /* Section 3.3.2.1. IPv6 Address Parameter (6) */
 274 typedef struct sctp_ipv6addr_param {
 275         sctp_paramhdr_t param_hdr;
 276         struct in6_addr addr;
 277 } __packed sctp_ipv6addr_param_t;
 278
 279 /* Section 3.3.2.1 Cookie Preservative (9) */
 280 typedef struct sctp_cookie_preserve_param {
 281         sctp_paramhdr_t param_hdr;
 282         __be32          lifespan_increment;
 283 } __packed sctp_cookie_preserve_param_t;
 284
 285 /* Section 3.3.2.1 Host Name Address (11) */
 286 typedef struct sctp_hostname_param {
 287         sctp_paramhdr_t param_hdr;
 288         uint8_t hostname[0];
 289 } __packed sctp_hostname_param_t;
 290
 291 /* Section 3.3.2.1 Supported Address Types (12) */
 292 typedef struct sctp_supported_addrs_param {
 293         sctp_paramhdr_t param_hdr;
 294         __be16 types[0];
 295 } __packed sctp_supported_addrs_param_t;
 296
 297 /* Appendix A. ECN Capable (32768) */
 298 typedef struct sctp_ecn_capable_param {
 299         sctp_paramhdr_t param_hdr;
 300 } __packed sctp_ecn_capable_param_t;
 301
 302 /* ADDIP Section 3.2.6 Adaptation Layer Indication */
 303 typedef struct sctp_adaptation_ind_param {
 304         struct sctp_paramhdr param_hdr;
 305         __be32 adaptation_ind;
 306 } __packed sctp_adaptation_ind_param_t;
 307
 308 /* ADDIP Section 4.2.7 Supported Extensions Parameter */
 309 typedef struct sctp_supported_ext_param {
 310         struct sctp_paramhdr param_hdr;
 311         __u8 chunks[0];
 312 } __packed sctp_supported_ext_param_t;
 313
 314 /* AUTH Section 3.1 Random */
 315 typedef struct sctp_random_param {
 316         sctp_paramhdr_t param_hdr;
 317         __u8 random_val[0];
 318 } __packed sctp_random_param_t;
 319
 320 /* AUTH Section 3.2 Chunk List */
 321 typedef struct sctp_chunks_param {
 322         sctp_paramhdr_t param_hdr;
 323         __u8 chunks[0];
 324 } __packed sctp_chunks_param_t;
 325
 326 /* AUTH Section 3.3 HMAC Algorithm */
 327 typedef struct sctp_hmac_algo_param {
 328         sctp_paramhdr_t param_hdr;
 329         __be16 hmac_ids[0];
 330 } __packed sctp_hmac_algo_param_t;
 331
 332 /* RFC 2960.  Section 3.3.3 Initiation Acknowledgement (INIT ACK) (2):
 333  *   The INIT ACK chunk is used to acknowledge the initiation of an SCTP
 334  *   association.
 335  */
 336 typedef sctp_init_chunk_t sctp_initack_chunk_t;
 337
 338 /* Section 3.3.3.1 State Cookie (7) */
 339 typedef struct sctp_cookie_param {
 340         sctp_paramhdr_t p;
 341         __u8 body[0];
 342 } __packed sctp_cookie_param_t;
 343
 344 /* Section 3.3.3.1 Unrecognized Parameters (8) */
 345 typedef struct sctp_unrecognized_param {
 346         sctp_paramhdr_t param_hdr;
 347         sctp_paramhdr_t unrecognized;
 348 } __packed sctp_unrecognized_param_t;
 349
 350
 351
 352 /*
 353  * 3.3.4 Selective Acknowledgement (SACK) (3):
 354  *
 355  *  This chunk is sent to the peer endpoint to acknowledge received DATA
 356  *  chunks and to inform the peer endpoint of gaps in the received
 357  *  subsequences of DATA chunks as represented by their TSNs.
 358  */
 359
 360 typedef struct sctp_gap_ack_block {
 361         __be16 start;
 362         __be16 end;
 363 } __packed sctp_gap_ack_block_t;
 364
 365 typedef __be32 sctp_dup_tsn_t;
 366
 367 typedef union {
 368         sctp_gap_ack_block_t    gab;
 369         sctp_dup_tsn_t          dup;
 370 } sctp_sack_variable_t;
 371
 372 typedef struct sctp_sackhdr {
 373         __be32 cum_tsn_ack;
 374         __be32 a_rwnd;
 375         __be16 num_gap_ack_blocks;
 376         __be16 num_dup_tsns;
 377         sctp_sack_variable_t variable[0];
 378 } __packed sctp_sackhdr_t;
 379
 380 typedef struct sctp_sack_chunk {
 381         sctp_chunkhdr_t chunk_hdr;
 382         sctp_sackhdr_t sack_hdr;
 383 } __packed sctp_sack_chunk_t;
 384
 385
 386 /* RFC 2960.  Section 3.3.5 Heartbeat Request (HEARTBEAT) (4):
 387  *
 388  *  An endpoint should send this chunk to its peer endpoint to probe the
 389  *  reachability of a particular destination transport address defined in
 390  *  the present association.
 391  */
 392
 393 typedef struct sctp_heartbeathdr {
 394         sctp_paramhdr_t info;
 395 } __packed sctp_heartbeathdr_t;
 396
 397 typedef struct sctp_heartbeat_chunk {
 398         sctp_chunkhdr_t chunk_hdr;
 399         sctp_heartbeathdr_t hb_hdr;
 400 } __packed sctp_heartbeat_chunk_t;
 401
 402
 403 /* For the abort and shutdown ACK we must carry the init tag in the
 404  * common header. Just the common header is all that is needed with a
 405  * chunk descriptor.
 406  */
 407 typedef struct sctp_abort_chunk {
 408         sctp_chunkhdr_t uh;
 409 } __packed sctp_abort_chunk_t;
 410
 411
 412 /* For the graceful shutdown we must carry the tag (in common header)
 413  * and the highest consecutive acking value.
 414  */
 415 typedef struct sctp_shutdownhdr {
 416         __be32 cum_tsn_ack;
 417 } __packed sctp_shutdownhdr_t;
 418
 419 struct sctp_shutdown_chunk_t {
 420         sctp_chunkhdr_t    chunk_hdr;
 421         sctp_shutdownhdr_t shutdown_hdr;
 422 } __packed;
 423
 424 /* RFC 2960.  Section 3.3.10 Operation Error (ERROR) (9) */
 425
 426 typedef struct sctp_errhdr {
 427         __be16 cause;
 428         __be16 length;
 429         __u8  variable[0];
 430 } __packed sctp_errhdr_t;
 431
 432 typedef struct sctp_operr_chunk {
 433         sctp_chunkhdr_t chunk_hdr;
 434         sctp_errhdr_t   err_hdr;
 435 } __packed sctp_operr_chunk_t;
 436
 437 /* RFC 2960 3.3.10 - Operation Error
 438  *
 439  * Cause Code: 16 bits (unsigned integer)
 440  *
 441  *     Defines the type of error conditions being reported.
 442  *    Cause Code
 443  *     Value           Cause Code
 444  *     ---------      ----------------
 445  *      1              Invalid Stream Identifier
 446  *      2              Missing Mandatory Parameter
 447  *      3              Stale Cookie Error
 448  *      4              Out of Resource
 449  *      5              Unresolvable Address
 450  *      6              Unrecognized Chunk Type
 451  *      7              Invalid Mandatory Parameter
 452  *      8              Unrecognized Parameters
 453  *      9              No User Data
 454  *     10              Cookie Received While Shutting Down
 455  */
 456 typedef enum {
 457
 458         SCTP_ERROR_NO_ERROR        = cpu_to_be16(0x00),
 459         SCTP_ERROR_INV_STRM        = cpu_to_be16(0x01),
 460         SCTP_ERROR_MISS_PARAM      = cpu_to_be16(0x02),
 461         SCTP_ERROR_STALE_COOKIE    = cpu_to_be16(0x03),
 462         SCTP_ERROR_NO_RESOURCE     = cpu_to_be16(0x04),
 463         SCTP_ERROR_DNS_FAILED      = cpu_to_be16(0x05),
 464         SCTP_ERROR_UNKNOWN_CHUNK   = cpu_to_be16(0x06),
 465         SCTP_ERROR_INV_PARAM       = cpu_to_be16(0x07),
 466         SCTP_ERROR_UNKNOWN_PARAM   = cpu_to_be16(0x08),
 467         SCTP_ERROR_NO_DATA         = cpu_to_be16(0x09),
 468         SCTP_ERROR_COOKIE_IN_SHUTDOWN = cpu_to_be16(0x0a),
 469
 470
 471         /* SCTP Implementation Guide:
 472          *  11  Restart of an association with new addresses
 473          *  12  User Initiated Abort
 474          *  13  Protocol Violation
 475          */
 476
 477         SCTP_ERROR_RESTART         = cpu_to_be16(0x0b),
 478         SCTP_ERROR_USER_ABORT      = cpu_to_be16(0x0c),
 479         SCTP_ERROR_PROTO_VIOLATION = cpu_to_be16(0x0d),
 480
 481         /* ADDIP Section 3.3  New Error Causes
 482          *
 483          * Four new Error Causes are added to the SCTP Operational Errors,
 484          * primarily for use in the ASCONF-ACK chunk.
 485          *
 486          * Value          Cause Code
 487          * ---------      ----------------
 488          * 0x00A0          Request to Delete Last Remaining IP Address.
 489          * 0x00A1          Operation Refused Due to Resource Shortage.
 490          * 0x00A2          Request to Delete Source IP Address.
 491          * 0x00A3          Association Aborted due to illegal ASCONF-ACK
 492          * 0x00A4          Request refused - no authorization.
 493          */
 494         SCTP_ERROR_DEL_LAST_IP  = cpu_to_be16(0x00A0),
 495         SCTP_ERROR_RSRC_LOW     = cpu_to_be16(0x00A1),
 496         SCTP_ERROR_DEL_SRC_IP   = cpu_to_be16(0x00A2),
 497         SCTP_ERROR_ASCONF_ACK   = cpu_to_be16(0x00A3),
 498         SCTP_ERROR_REQ_REFUSED  = cpu_to_be16(0x00A4),
 499
 500         /* AUTH Section 4.  New Error Cause
 501          *
 502          * This section defines a new error cause that will be sent if an AUTH
 503          * chunk is received with an unsupported HMAC identifier.
 504          * illustrates the new error cause.
 505          *
 506          * Cause Code      Error Cause Name
 507          * --------------------------------------------------------------
 508          * 0x0105          Unsupported HMAC Identifier
 509          */
 510          SCTP_ERROR_UNSUP_HMAC  = cpu_to_be16(0x0105)
 511 } sctp_error_t;
 512
 513
 514
 515 /* RFC 2960.  Appendix A.  Explicit Congestion Notification.
 516  *   Explicit Congestion Notification Echo (ECNE) (12)
 517  */
 518 typedef struct sctp_ecnehdr {
 519         __be32 lowest_tsn;
 520 } sctp_ecnehdr_t;
 521
 522 typedef struct sctp_ecne_chunk {
 523         sctp_chunkhdr_t chunk_hdr;
 524         sctp_ecnehdr_t ence_hdr;
 525 } __packed sctp_ecne_chunk_t;
 526
 527 /* RFC 2960.  Appendix A.  Explicit Congestion Notification.
 528  *   Congestion Window Reduced (CWR) (13)
 529  */
 530 typedef struct sctp_cwrhdr {
 531         __be32 lowest_tsn;
 532 } sctp_cwrhdr_t;
 533
 534 typedef struct sctp_cwr_chunk {
 535         sctp_chunkhdr_t chunk_hdr;
 536         sctp_cwrhdr_t cwr_hdr;
 537 } __packed sctp_cwr_chunk_t;
 538
 539 /* PR-SCTP
 540  * 3.2 Forward Cumulative TSN Chunk Definition (FORWARD TSN)
 541  *
 542  * Forward Cumulative TSN chunk has the following format:
 543  *
 544  *        0                   1                   2                   3
 545  *        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 546  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 547  *      |   Type = 192  |  Flags = 0x00 |        Length = Variable      |
 548  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 549  *      |                      New Cumulative TSN                       |
 550  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 551  *      |         Stream-1              |       Stream Sequence-1       |
 552  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 553  *      \                                                               /
 554  *      /                                                               \
 555  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 556  *      |         Stream-N              |       Stream Sequence-N       |
 557  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 558  *
 559  *      Chunk Flags:
 560  *
 561  *        Set to all zeros on transmit and ignored on receipt.
 562  *
 563  *      New Cumulative TSN: 32 bit u_int
 564  *
 565  *       This indicates the new cumulative TSN to the data receiver. Upon
 566  *       the reception of this value, the data receiver MUST consider
 567  *       any missing TSNs earlier than or equal to this value as received
 568  *       and stop reporting them as gaps in any subsequent SACKs.
 569  *
 570  *      Stream-N: 16 bit u_int
 571  *
 572  *       This field holds a stream number that was skipped by this
 573  *       FWD-TSN.
 574  *
 575  *      Stream Sequence-N: 16 bit u_int
 576  *       This field holds the sequence number associated with the stream
 577  *       that was skipped. The stream sequence field holds the largest stream
 578  *       sequence number in this stream being skipped.  The receiver of
 579  *       the FWD-TSN's can use the Stream-N and Stream Sequence-N fields
 580  *       to enable delivery of any stranded TSN's that remain on the stream
 581  *       re-ordering queues. This field MUST NOT report TSN's corresponding
 582  *       to DATA chunk that are marked as unordered. For ordered DATA
 583  *       chunks this field MUST be filled in.
 584  */
 585 struct sctp_fwdtsn_skip {
 586         __be16 stream;
 587         __be16 ssn;
 588 } __packed;
 589
 590 struct sctp_fwdtsn_hdr {
 591         __be32 new_cum_tsn;
 592         struct sctp_fwdtsn_skip skip[0];
 593 } __packed;
 594
 595 struct sctp_fwdtsn_chunk {
 596         struct sctp_chunkhdr chunk_hdr;
 597         struct sctp_fwdtsn_hdr fwdtsn_hdr;
 598 } __packed;
 599
 600
 601 /* ADDIP
 602  * Section 3.1.1 Address Configuration Change Chunk (ASCONF)
 603  *
 604  *      Serial Number: 32 bits (unsigned integer)
 605  *      This value represents a Serial Number for the ASCONF Chunk. The
 606  *      valid range of Serial Number is from 0 to 2^32-1.
 607  *      Serial Numbers wrap back to 0 after reaching 2^32 -1.
 608  *
 609  *      Address Parameter: 8 or 20 bytes (depending on type)
 610  *      The address is an address of the sender of the ASCONF chunk,
 611  *      the address MUST be considered part of the association by the
 612  *      peer endpoint. This field may be used by the receiver of the
 613  *      ASCONF to help in finding the association. This parameter MUST
 614  *      be present in every ASCONF message i.e. it is a mandatory TLV
 615  *      parameter.
 616  *
 617  *      ASCONF Parameter: TLV format
 618  *      Each Address configuration change is represented by a TLV
 619  *      parameter as defined in Section 3.2. One or more requests may
 620  *      be present in an ASCONF Chunk.
 621  *
 622  * Section 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
 623  *
 624  *      Serial Number: 32 bits (unsigned integer)
 625  *      This value represents the Serial Number for the received ASCONF
 626  *      Chunk that is acknowledged by this chunk. This value is copied
 627  *      from the received ASCONF Chunk.
 628  *
 629  *      ASCONF Parameter Response: TLV format
 630  *      The ASCONF Parameter Response is used in the ASCONF-ACK to
 631  *      report status of ASCONF processing.
 632  */
 633 typedef struct sctp_addip_param {
 634         sctp_paramhdr_t param_hdr;
 635         __be32          crr_id;
 636 } __packed sctp_addip_param_t;
 637
 638 typedef struct sctp_addiphdr {
 639         __be32  serial;
 640         __u8    params[0];
 641 } __packed sctp_addiphdr_t;
 642
 643 typedef struct sctp_addip_chunk {
 644         sctp_chunkhdr_t chunk_hdr;
 645         sctp_addiphdr_t addip_hdr;
 646 } __packed sctp_addip_chunk_t;
 647
 648 /* AUTH
 649  * Section 4.1  Authentication Chunk (AUTH)
 650  *
 651  *   This chunk is used to hold the result of the HMAC calculation.
 652  *
 653  *    0                   1                   2                   3
 654  *    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 655  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 656  *   | Type = 0x0F   |   Flags=0     |             Length            |
 657  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 658  *   |     Shared Key Identifier     |   HMAC Identifier             |
 659  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 660  *   |                                                               |
 661  *   \                             HMAC                              /
 662  *   /                                                               \
 663  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 664  *
 665  *   Type: 1 byte (unsigned integer)
 666  *      This value MUST be set to 0x0F for  all AUTH-chunks.
 667  *
 668  *   Flags: 1 byte (unsigned integer)
 669  *      Set to zero on transmit and ignored on receipt.
 670  *
 671  *   Length: 2 bytes (unsigned integer)
 672  *      This value holds the length of the HMAC in bytes plus 8.
 673  *
 674  *  Shared Key Identifier: 2 bytes (unsigned integer)
 675  *      This value describes which endpoint pair shared key is used.
 676  *
 677  *   HMAC Identifier: 2 bytes (unsigned integer)
 678  *      This value describes which message digest is being used.  Table 2
 679  *      shows the currently defined values.
 680  *
 681  *    The following Table 2 shows the currently defined values for HMAC
 682  *       identifiers.
 683  *
 684  *       +-----------------+--------------------------+
 685  *       | HMAC Identifier | Message Digest Algorithm |
 686  *       +-----------------+--------------------------+
 687  *       | 0               | Reserved                 |
 688  *       | 1               | SHA-1 defined in [8]     |
 689  *       | 2               | Reserved                 |
 690  *       | 3               | SHA-256 defined in [8]   |
 691  *       +-----------------+--------------------------+
 692  *
 693  *
 694  *   HMAC: n bytes (unsigned integer) This hold the result of the HMAC
 695  *      calculation.
 696  */
 697 typedef struct sctp_authhdr {
 698         __be16 shkey_id;
 699         __be16 hmac_id;
 700         __u8   hmac[0];
 701 } __packed sctp_authhdr_t;
 702
 703 typedef struct sctp_auth_chunk {
 704         sctp_chunkhdr_t chunk_hdr;
 705         sctp_authhdr_t auth_hdr;
 706 } __packed sctp_auth_chunk_t;
 707
 708 #endif /* __LINUX_SCTP_H__ */