xref: /linux-6.15/include/linux/sctp.h (revision f5e4e7fd)
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, write to
27  * the Free Software Foundation, 59 Temple Place - Suite 330,
28  * Boston, MA 02111-1307, USA.
29  *
30  * Please send any bug reports or fixes you make to the
31  * email address(es):
32  *    lksctp developers <[email protected]>
33  *
34  * Or submit a bug report through the following website:
35  *    http://www.sf.net/projects/lksctp
36  *
37  * Written or modified by:
38  *    La Monte H.P. Yarroll <[email protected]>
39  *    Karl Knutson <[email protected]>
40  *    Jon Grimm <[email protected]>
41  *    Xingang Guo <[email protected]>
42  *    [email protected]
43  *    [email protected]
44  *    [email protected]
45  *    Sridhar Samudrala <[email protected]>
46  *    Kevin Gao <[email protected]>
47  *
48  * Any bugs reported given to us we will try to fix... any fixes shared will
49  * be incorporated into the next SCTP release.
50  */
51 #ifndef __LINUX_SCTP_H__
52 #define __LINUX_SCTP_H__
53 
54 #include <linux/in.h>		/* We need in_addr.  */
55 #include <linux/in6.h>		/* We need in6_addr.  */
56 #include <linux/skbuff.h>
57 
58 #include <uapi/linux/sctp.h>
59 
60 /* Section 3.1.  SCTP Common Header Format */
61 typedef struct sctphdr {
62 	__be16 source;
63 	__be16 dest;
64 	__be32 vtag;
65 	__le32 checksum;
66 } __packed sctp_sctphdr_t;
67 
68 static inline struct sctphdr *sctp_hdr(const struct sk_buff *skb)
69 {
70 	return (struct sctphdr *)skb_transport_header(skb);
71 }
72 
73 /* Section 3.2.  Chunk Field Descriptions. */
74 typedef struct sctp_chunkhdr {
75 	__u8 type;
76 	__u8 flags;
77 	__be16 length;
78 } __packed sctp_chunkhdr_t;
79 
80 
81 /* Section 3.2.  Chunk Type Values.
82  * [Chunk Type] identifies the type of information contained in the Chunk
83  * Value field. It takes a value from 0 to 254. The value of 255 is
84  * reserved for future use as an extension field.
85  */
86 typedef enum {
87 	SCTP_CID_DATA			= 0,
88         SCTP_CID_INIT			= 1,
89         SCTP_CID_INIT_ACK		= 2,
90         SCTP_CID_SACK			= 3,
91         SCTP_CID_HEARTBEAT		= 4,
92         SCTP_CID_HEARTBEAT_ACK		= 5,
93         SCTP_CID_ABORT			= 6,
94         SCTP_CID_SHUTDOWN		= 7,
95         SCTP_CID_SHUTDOWN_ACK		= 8,
96         SCTP_CID_ERROR			= 9,
97         SCTP_CID_COOKIE_ECHO		= 10,
98         SCTP_CID_COOKIE_ACK	        = 11,
99         SCTP_CID_ECN_ECNE		= 12,
100         SCTP_CID_ECN_CWR		= 13,
101         SCTP_CID_SHUTDOWN_COMPLETE	= 14,
102 
103 	/* AUTH Extension Section 4.1 */
104 	SCTP_CID_AUTH			= 0x0F,
105 
106 	/* PR-SCTP Sec 3.2 */
107 	SCTP_CID_FWD_TSN		= 0xC0,
108 
109 	/* Use hex, as defined in ADDIP sec. 3.1 */
110 	SCTP_CID_ASCONF			= 0xC1,
111 	SCTP_CID_ASCONF_ACK		= 0x80,
112 } sctp_cid_t; /* enum */
113 
114 
115 /* Section 3.2
116  *  Chunk Types are encoded such that the highest-order two bits specify
117  *  the action that must be taken if the processing endpoint does not
118  *  recognize the Chunk Type.
119  */
120 typedef enum {
121 	SCTP_CID_ACTION_DISCARD     = 0x00,
122 	SCTP_CID_ACTION_DISCARD_ERR = 0x40,
123 	SCTP_CID_ACTION_SKIP        = 0x80,
124 	SCTP_CID_ACTION_SKIP_ERR    = 0xc0,
125 } sctp_cid_action_t;
126 
127 enum { SCTP_CID_ACTION_MASK = 0xc0, };
128 
129 /* This flag is used in Chunk Flags for ABORT and SHUTDOWN COMPLETE.
130  *
131  * 3.3.7 Abort Association (ABORT) (6):
132  *    The T bit is set to 0 if the sender had a TCB that it destroyed.
133  *    If the sender did not have a TCB it should set this bit to 1.
134  */
135 enum { SCTP_CHUNK_FLAG_T = 0x01 };
136 
137 /*
138  *  Set the T bit
139  *
140  *      0                   1                   2                   3
141  *      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
142  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
143  *     |   Type = 14   |Reserved     |T|      Length = 4               |
144  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
145  *
146  * Chunk Flags: 8 bits
147  *
148  *   Reserved:  7 bits
149  *     Set to 0 on transmit and ignored on receipt.
150  *
151  *   T bit:  1 bit
152  *     The T bit is set to 0 if the sender had a TCB that it destroyed. If
153  *     the sender did NOT have a TCB it should set this bit to 1.
154  *
155  * Note: Special rules apply to this chunk for verification, please
156  * see Section 8.5.1 for details.
157  */
158 
159 #define sctp_test_T_bit(c)    ((c)->chunk_hdr->flags & SCTP_CHUNK_FLAG_T)
160 
161 /* RFC 2960
162  * Section 3.2.1 Optional/Variable-length Parmaeter Format.
163  */
164 
165 typedef struct sctp_paramhdr {
166 	__be16 type;
167 	__be16 length;
168 } __packed sctp_paramhdr_t;
169 
170 typedef enum {
171 
172 	/* RFC 2960 Section 3.3.5 */
173 	SCTP_PARAM_HEARTBEAT_INFO		= cpu_to_be16(1),
174 	/* RFC 2960 Section 3.3.2.1 */
175 	SCTP_PARAM_IPV4_ADDRESS			= cpu_to_be16(5),
176 	SCTP_PARAM_IPV6_ADDRESS			= cpu_to_be16(6),
177 	SCTP_PARAM_STATE_COOKIE			= cpu_to_be16(7),
178 	SCTP_PARAM_UNRECOGNIZED_PARAMETERS	= cpu_to_be16(8),
179 	SCTP_PARAM_COOKIE_PRESERVATIVE		= cpu_to_be16(9),
180 	SCTP_PARAM_HOST_NAME_ADDRESS		= cpu_to_be16(11),
181 	SCTP_PARAM_SUPPORTED_ADDRESS_TYPES	= cpu_to_be16(12),
182 	SCTP_PARAM_ECN_CAPABLE			= cpu_to_be16(0x8000),
183 
184 	/* AUTH Extension Section 3 */
185 	SCTP_PARAM_RANDOM			= cpu_to_be16(0x8002),
186 	SCTP_PARAM_CHUNKS			= cpu_to_be16(0x8003),
187 	SCTP_PARAM_HMAC_ALGO			= cpu_to_be16(0x8004),
188 
189 	/* Add-IP: Supported Extensions, Section 4.2 */
190 	SCTP_PARAM_SUPPORTED_EXT	= cpu_to_be16(0x8008),
191 
192 	/* PR-SCTP Sec 3.1 */
193 	SCTP_PARAM_FWD_TSN_SUPPORT	= cpu_to_be16(0xc000),
194 
195 	/* Add-IP Extension. Section 3.2 */
196 	SCTP_PARAM_ADD_IP		= cpu_to_be16(0xc001),
197 	SCTP_PARAM_DEL_IP		= cpu_to_be16(0xc002),
198 	SCTP_PARAM_ERR_CAUSE		= cpu_to_be16(0xc003),
199 	SCTP_PARAM_SET_PRIMARY		= cpu_to_be16(0xc004),
200 	SCTP_PARAM_SUCCESS_REPORT	= cpu_to_be16(0xc005),
201 	SCTP_PARAM_ADAPTATION_LAYER_IND = cpu_to_be16(0xc006),
202 
203 } sctp_param_t; /* enum */
204 
205 
206 /* RFC 2960 Section 3.2.1
207  *  The Parameter Types are encoded such that the highest-order two bits
208  *  specify the action that must be taken if the processing endpoint does
209  *  not recognize the Parameter Type.
210  *
211  */
212 typedef enum {
213 	SCTP_PARAM_ACTION_DISCARD     = cpu_to_be16(0x0000),
214 	SCTP_PARAM_ACTION_DISCARD_ERR = cpu_to_be16(0x4000),
215 	SCTP_PARAM_ACTION_SKIP        = cpu_to_be16(0x8000),
216 	SCTP_PARAM_ACTION_SKIP_ERR    = cpu_to_be16(0xc000),
217 } sctp_param_action_t;
218 
219 enum { SCTP_PARAM_ACTION_MASK = cpu_to_be16(0xc000), };
220 
221 /* RFC 2960 Section 3.3.1 Payload Data (DATA) (0) */
222 
223 typedef struct sctp_datahdr {
224 	__be32 tsn;
225 	__be16 stream;
226 	__be16 ssn;
227 	__be32 ppid;
228 	__u8  payload[0];
229 } __packed sctp_datahdr_t;
230 
231 typedef struct sctp_data_chunk {
232         sctp_chunkhdr_t chunk_hdr;
233         sctp_datahdr_t  data_hdr;
234 } __packed sctp_data_chunk_t;
235 
236 /* DATA Chuck Specific Flags */
237 enum {
238 	SCTP_DATA_MIDDLE_FRAG	= 0x00,
239 	SCTP_DATA_LAST_FRAG	= 0x01,
240 	SCTP_DATA_FIRST_FRAG	= 0x02,
241 	SCTP_DATA_NOT_FRAG	= 0x03,
242 	SCTP_DATA_UNORDERED	= 0x04,
243 	SCTP_DATA_SACK_IMM	= 0x08,
244 };
245 enum { SCTP_DATA_FRAG_MASK = 0x03, };
246 
247 
248 /* RFC 2960 Section 3.3.2 Initiation (INIT) (1)
249  *
250  *  This chunk is used to initiate a SCTP association between two
251  *  endpoints.
252  */
253 typedef struct sctp_inithdr {
254 	__be32 init_tag;
255 	__be32 a_rwnd;
256 	__be16 num_outbound_streams;
257 	__be16 num_inbound_streams;
258 	__be32 initial_tsn;
259 	__u8  params[0];
260 } __packed sctp_inithdr_t;
261 
262 typedef struct sctp_init_chunk {
263 	sctp_chunkhdr_t chunk_hdr;
264 	sctp_inithdr_t init_hdr;
265 } __packed sctp_init_chunk_t;
266 
267 
268 /* Section 3.3.2.1. IPv4 Address Parameter (5) */
269 typedef struct sctp_ipv4addr_param {
270 	sctp_paramhdr_t param_hdr;
271 	struct in_addr  addr;
272 } __packed sctp_ipv4addr_param_t;
273 
274 /* Section 3.3.2.1. IPv6 Address Parameter (6) */
275 typedef struct sctp_ipv6addr_param {
276 	sctp_paramhdr_t param_hdr;
277 	struct in6_addr addr;
278 } __packed sctp_ipv6addr_param_t;
279 
280 /* Section 3.3.2.1 Cookie Preservative (9) */
281 typedef struct sctp_cookie_preserve_param {
282 	sctp_paramhdr_t param_hdr;
283 	__be32          lifespan_increment;
284 } __packed sctp_cookie_preserve_param_t;
285 
286 /* Section 3.3.2.1 Host Name Address (11) */
287 typedef struct sctp_hostname_param {
288 	sctp_paramhdr_t param_hdr;
289 	uint8_t hostname[0];
290 } __packed sctp_hostname_param_t;
291 
292 /* Section 3.3.2.1 Supported Address Types (12) */
293 typedef struct sctp_supported_addrs_param {
294 	sctp_paramhdr_t param_hdr;
295 	__be16 types[0];
296 } __packed sctp_supported_addrs_param_t;
297 
298 /* Appendix A. ECN Capable (32768) */
299 typedef struct sctp_ecn_capable_param {
300 	sctp_paramhdr_t param_hdr;
301 } __packed sctp_ecn_capable_param_t;
302 
303 /* ADDIP Section 3.2.6 Adaptation Layer Indication */
304 typedef struct sctp_adaptation_ind_param {
305 	struct sctp_paramhdr param_hdr;
306 	__be32 adaptation_ind;
307 } __packed sctp_adaptation_ind_param_t;
308 
309 /* ADDIP Section 4.2.7 Supported Extensions Parameter */
310 typedef struct sctp_supported_ext_param {
311 	struct sctp_paramhdr param_hdr;
312 	__u8 chunks[0];
313 } __packed sctp_supported_ext_param_t;
314 
315 /* AUTH Section 3.1 Random */
316 typedef struct sctp_random_param {
317 	sctp_paramhdr_t param_hdr;
318 	__u8 random_val[0];
319 } __packed sctp_random_param_t;
320 
321 /* AUTH Section 3.2 Chunk List */
322 typedef struct sctp_chunks_param {
323 	sctp_paramhdr_t param_hdr;
324 	__u8 chunks[0];
325 } __packed sctp_chunks_param_t;
326 
327 /* AUTH Section 3.3 HMAC Algorithm */
328 typedef struct sctp_hmac_algo_param {
329 	sctp_paramhdr_t param_hdr;
330 	__be16 hmac_ids[0];
331 } __packed sctp_hmac_algo_param_t;
332 
333 /* RFC 2960.  Section 3.3.3 Initiation Acknowledgement (INIT ACK) (2):
334  *   The INIT ACK chunk is used to acknowledge the initiation of an SCTP
335  *   association.
336  */
337 typedef sctp_init_chunk_t sctp_initack_chunk_t;
338 
339 /* Section 3.3.3.1 State Cookie (7) */
340 typedef struct sctp_cookie_param {
341 	sctp_paramhdr_t p;
342 	__u8 body[0];
343 } __packed sctp_cookie_param_t;
344 
345 /* Section 3.3.3.1 Unrecognized Parameters (8) */
346 typedef struct sctp_unrecognized_param {
347 	sctp_paramhdr_t param_hdr;
348 	sctp_paramhdr_t unrecognized;
349 } __packed sctp_unrecognized_param_t;
350 
351 
352 
353 /*
354  * 3.3.4 Selective Acknowledgement (SACK) (3):
355  *
356  *  This chunk is sent to the peer endpoint to acknowledge received DATA
357  *  chunks and to inform the peer endpoint of gaps in the received
358  *  subsequences of DATA chunks as represented by their TSNs.
359  */
360 
361 typedef struct sctp_gap_ack_block {
362 	__be16 start;
363 	__be16 end;
364 } __packed sctp_gap_ack_block_t;
365 
366 typedef __be32 sctp_dup_tsn_t;
367 
368 typedef union {
369 	sctp_gap_ack_block_t	gab;
370         sctp_dup_tsn_t		dup;
371 } sctp_sack_variable_t;
372 
373 typedef struct sctp_sackhdr {
374 	__be32 cum_tsn_ack;
375 	__be32 a_rwnd;
376 	__be16 num_gap_ack_blocks;
377 	__be16 num_dup_tsns;
378 	sctp_sack_variable_t variable[0];
379 } __packed sctp_sackhdr_t;
380 
381 typedef struct sctp_sack_chunk {
382 	sctp_chunkhdr_t chunk_hdr;
383 	sctp_sackhdr_t sack_hdr;
384 } __packed sctp_sack_chunk_t;
385 
386 
387 /* RFC 2960.  Section 3.3.5 Heartbeat Request (HEARTBEAT) (4):
388  *
389  *  An endpoint should send this chunk to its peer endpoint to probe the
390  *  reachability of a particular destination transport address defined in
391  *  the present association.
392  */
393 
394 typedef struct sctp_heartbeathdr {
395 	sctp_paramhdr_t info;
396 } __packed sctp_heartbeathdr_t;
397 
398 typedef struct sctp_heartbeat_chunk {
399 	sctp_chunkhdr_t chunk_hdr;
400 	sctp_heartbeathdr_t hb_hdr;
401 } __packed sctp_heartbeat_chunk_t;
402 
403 
404 /* For the abort and shutdown ACK we must carry the init tag in the
405  * common header. Just the common header is all that is needed with a
406  * chunk descriptor.
407  */
408 typedef struct sctp_abort_chunk {
409         sctp_chunkhdr_t uh;
410 } __packed sctp_abort_chunk_t;
411 
412 
413 /* For the graceful shutdown we must carry the tag (in common header)
414  * and the highest consecutive acking value.
415  */
416 typedef struct sctp_shutdownhdr {
417 	__be32 cum_tsn_ack;
418 } __packed sctp_shutdownhdr_t;
419 
420 struct sctp_shutdown_chunk_t {
421         sctp_chunkhdr_t    chunk_hdr;
422         sctp_shutdownhdr_t shutdown_hdr;
423 } __packed;
424 
425 /* RFC 2960.  Section 3.3.10 Operation Error (ERROR) (9) */
426 
427 typedef struct sctp_errhdr {
428 	__be16 cause;
429 	__be16 length;
430 	__u8  variable[0];
431 } __packed sctp_errhdr_t;
432 
433 typedef struct sctp_operr_chunk {
434         sctp_chunkhdr_t chunk_hdr;
435 	sctp_errhdr_t   err_hdr;
436 } __packed sctp_operr_chunk_t;
437 
438 /* RFC 2960 3.3.10 - Operation Error
439  *
440  * Cause Code: 16 bits (unsigned integer)
441  *
442  *     Defines the type of error conditions being reported.
443  *    Cause Code
444  *     Value           Cause Code
445  *     ---------      ----------------
446  *      1              Invalid Stream Identifier
447  *      2              Missing Mandatory Parameter
448  *      3              Stale Cookie Error
449  *      4              Out of Resource
450  *      5              Unresolvable Address
451  *      6              Unrecognized Chunk Type
452  *      7              Invalid Mandatory Parameter
453  *      8              Unrecognized Parameters
454  *      9              No User Data
455  *     10              Cookie Received While Shutting Down
456  */
457 typedef enum {
458 
459 	SCTP_ERROR_NO_ERROR	   = cpu_to_be16(0x00),
460 	SCTP_ERROR_INV_STRM	   = cpu_to_be16(0x01),
461 	SCTP_ERROR_MISS_PARAM 	   = cpu_to_be16(0x02),
462 	SCTP_ERROR_STALE_COOKIE	   = cpu_to_be16(0x03),
463 	SCTP_ERROR_NO_RESOURCE 	   = cpu_to_be16(0x04),
464 	SCTP_ERROR_DNS_FAILED      = cpu_to_be16(0x05),
465 	SCTP_ERROR_UNKNOWN_CHUNK   = cpu_to_be16(0x06),
466 	SCTP_ERROR_INV_PARAM       = cpu_to_be16(0x07),
467 	SCTP_ERROR_UNKNOWN_PARAM   = cpu_to_be16(0x08),
468 	SCTP_ERROR_NO_DATA         = cpu_to_be16(0x09),
469 	SCTP_ERROR_COOKIE_IN_SHUTDOWN = cpu_to_be16(0x0a),
470 
471 
472 	/* SCTP Implementation Guide:
473 	 *  11  Restart of an association with new addresses
474 	 *  12  User Initiated Abort
475 	 *  13  Protocol Violation
476 	 */
477 
478 	SCTP_ERROR_RESTART         = cpu_to_be16(0x0b),
479 	SCTP_ERROR_USER_ABORT      = cpu_to_be16(0x0c),
480 	SCTP_ERROR_PROTO_VIOLATION = cpu_to_be16(0x0d),
481 
482 	/* ADDIP Section 3.3  New Error Causes
483 	 *
484 	 * Four new Error Causes are added to the SCTP Operational Errors,
485 	 * primarily for use in the ASCONF-ACK chunk.
486 	 *
487 	 * Value          Cause Code
488 	 * ---------      ----------------
489 	 * 0x00A0          Request to Delete Last Remaining IP Address.
490 	 * 0x00A1          Operation Refused Due to Resource Shortage.
491 	 * 0x00A2          Request to Delete Source IP Address.
492 	 * 0x00A3          Association Aborted due to illegal ASCONF-ACK
493 	 * 0x00A4          Request refused - no authorization.
494 	 */
495 	SCTP_ERROR_DEL_LAST_IP	= cpu_to_be16(0x00A0),
496 	SCTP_ERROR_RSRC_LOW	= cpu_to_be16(0x00A1),
497 	SCTP_ERROR_DEL_SRC_IP	= cpu_to_be16(0x00A2),
498 	SCTP_ERROR_ASCONF_ACK   = cpu_to_be16(0x00A3),
499 	SCTP_ERROR_REQ_REFUSED	= cpu_to_be16(0x00A4),
500 
501 	/* AUTH Section 4.  New Error Cause
502 	 *
503 	 * This section defines a new error cause that will be sent if an AUTH
504 	 * chunk is received with an unsupported HMAC identifier.
505 	 * illustrates the new error cause.
506 	 *
507 	 * Cause Code      Error Cause Name
508 	 * --------------------------------------------------------------
509 	 * 0x0105          Unsupported HMAC Identifier
510 	 */
511 	 SCTP_ERROR_UNSUP_HMAC	= cpu_to_be16(0x0105)
512 } sctp_error_t;
513 
514 
515 
516 /* RFC 2960.  Appendix A.  Explicit Congestion Notification.
517  *   Explicit Congestion Notification Echo (ECNE) (12)
518  */
519 typedef struct sctp_ecnehdr {
520 	__be32 lowest_tsn;
521 } sctp_ecnehdr_t;
522 
523 typedef struct sctp_ecne_chunk {
524 	sctp_chunkhdr_t chunk_hdr;
525 	sctp_ecnehdr_t ence_hdr;
526 } __packed sctp_ecne_chunk_t;
527 
528 /* RFC 2960.  Appendix A.  Explicit Congestion Notification.
529  *   Congestion Window Reduced (CWR) (13)
530  */
531 typedef struct sctp_cwrhdr {
532 	__be32 lowest_tsn;
533 } sctp_cwrhdr_t;
534 
535 typedef struct sctp_cwr_chunk {
536 	sctp_chunkhdr_t chunk_hdr;
537 	sctp_cwrhdr_t cwr_hdr;
538 } __packed sctp_cwr_chunk_t;
539 
540 /* PR-SCTP
541  * 3.2 Forward Cumulative TSN Chunk Definition (FORWARD TSN)
542  *
543  * Forward Cumulative TSN chunk has the following format:
544  *
545  *        0                   1                   2                   3
546  *        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
547  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
548  *      |   Type = 192  |  Flags = 0x00 |        Length = Variable      |
549  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
550  *      |                      New Cumulative TSN                       |
551  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
552  *      |         Stream-1              |       Stream Sequence-1       |
553  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
554  *      \                                                               /
555  *      /                                                               \
556  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
557  *      |         Stream-N              |       Stream Sequence-N       |
558  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
559  *
560  *      Chunk Flags:
561  *
562  *        Set to all zeros on transmit and ignored on receipt.
563  *
564  *      New Cumulative TSN: 32 bit u_int
565  *
566  *       This indicates the new cumulative TSN to the data receiver. Upon
567  *       the reception of this value, the data receiver MUST consider
568  *       any missing TSNs earlier than or equal to this value as received
569  *       and stop reporting them as gaps in any subsequent SACKs.
570  *
571  *      Stream-N: 16 bit u_int
572  *
573  *       This field holds a stream number that was skipped by this
574  *       FWD-TSN.
575  *
576  *      Stream Sequence-N: 16 bit u_int
577  *       This field holds the sequence number associated with the stream
578  *       that was skipped. The stream sequence field holds the largest stream
579  *       sequence number in this stream being skipped.  The receiver of
580  *       the FWD-TSN's can use the Stream-N and Stream Sequence-N fields
581  *       to enable delivery of any stranded TSN's that remain on the stream
582  *       re-ordering queues. This field MUST NOT report TSN's corresponding
583  *       to DATA chunk that are marked as unordered. For ordered DATA
584  *       chunks this field MUST be filled in.
585  */
586 struct sctp_fwdtsn_skip {
587 	__be16 stream;
588 	__be16 ssn;
589 } __packed;
590 
591 struct sctp_fwdtsn_hdr {
592 	__be32 new_cum_tsn;
593 	struct sctp_fwdtsn_skip skip[0];
594 } __packed;
595 
596 struct sctp_fwdtsn_chunk {
597 	struct sctp_chunkhdr chunk_hdr;
598 	struct sctp_fwdtsn_hdr fwdtsn_hdr;
599 } __packed;
600 
601 
602 /* ADDIP
603  * Section 3.1.1 Address Configuration Change Chunk (ASCONF)
604  *
605  * 	Serial Number: 32 bits (unsigned integer)
606  *	This value represents a Serial Number for the ASCONF Chunk. The
607  *	valid range of Serial Number is from 0 to 2^32-1.
608  *	Serial Numbers wrap back to 0 after reaching 2^32 -1.
609  *
610  *	Address Parameter: 8 or 20 bytes (depending on type)
611  *	The address is an address of the sender of the ASCONF chunk,
612  *	the address MUST be considered part of the association by the
613  *	peer endpoint. This field may be used by the receiver of the
614  *	ASCONF to help in finding the association. This parameter MUST
615  *	be present in every ASCONF message i.e. it is a mandatory TLV
616  *	parameter.
617  *
618  *	ASCONF Parameter: TLV format
619  *	Each Address configuration change is represented by a TLV
620  *	parameter as defined in Section 3.2. One or more requests may
621  *	be present in an ASCONF Chunk.
622  *
623  * Section 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
624  *
625  *	Serial Number: 32 bits (unsigned integer)
626  *	This value represents the Serial Number for the received ASCONF
627  *	Chunk that is acknowledged by this chunk. This value is copied
628  *	from the received ASCONF Chunk.
629  *
630  *	ASCONF Parameter Response: TLV format
631  *	The ASCONF Parameter Response is used in the ASCONF-ACK to
632  *	report status of ASCONF processing.
633  */
634 typedef struct sctp_addip_param {
635 	sctp_paramhdr_t	param_hdr;
636 	__be32		crr_id;
637 } __packed sctp_addip_param_t;
638 
639 typedef struct sctp_addiphdr {
640 	__be32	serial;
641 	__u8	params[0];
642 } __packed sctp_addiphdr_t;
643 
644 typedef struct sctp_addip_chunk {
645 	sctp_chunkhdr_t chunk_hdr;
646 	sctp_addiphdr_t addip_hdr;
647 } __packed sctp_addip_chunk_t;
648 
649 /* AUTH
650  * Section 4.1  Authentication Chunk (AUTH)
651  *
652  *   This chunk is used to hold the result of the HMAC calculation.
653  *
654  *    0                   1                   2                   3
655  *    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
656  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
657  *   | Type = 0x0F   |   Flags=0     |             Length            |
658  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
659  *   |     Shared Key Identifier     |   HMAC Identifier             |
660  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
661  *   |                                                               |
662  *   \                             HMAC                              /
663  *   /                                                               \
664  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
665  *
666  *   Type: 1 byte (unsigned integer)
667  *   	This value MUST be set to 0x0F for  all AUTH-chunks.
668  *
669  *   Flags: 1 byte (unsigned integer)
670  *	Set to zero on transmit and ignored on receipt.
671  *
672  *   Length: 2 bytes (unsigned integer)
673  *   	This value holds the length of the HMAC in bytes plus 8.
674  *
675  *  Shared Key Identifier: 2 bytes (unsigned integer)
676  *	This value describes which endpoint pair shared key is used.
677  *
678  *   HMAC Identifier: 2 bytes (unsigned integer)
679  *   	This value describes which message digest is being used.  Table 2
680  *	shows the currently defined values.
681  *
682  *    The following Table 2 shows the currently defined values for HMAC
683  *       identifiers.
684  *
685  *	 +-----------------+--------------------------+
686  *	 | HMAC Identifier | Message Digest Algorithm |
687  *	 +-----------------+--------------------------+
688  *	 | 0               | Reserved                 |
689  *	 | 1               | SHA-1 defined in [8]     |
690  *	 | 2               | Reserved                 |
691  *	 | 3               | SHA-256 defined in [8]   |
692  *	 +-----------------+--------------------------+
693  *
694  *
695  *   HMAC: n bytes (unsigned integer) This hold the result of the HMAC
696  *      calculation.
697  */
698 typedef struct sctp_authhdr {
699 	__be16 shkey_id;
700 	__be16 hmac_id;
701 	__u8   hmac[0];
702 } __packed sctp_authhdr_t;
703 
704 typedef struct sctp_auth_chunk {
705 	sctp_chunkhdr_t chunk_hdr;
706 	sctp_authhdr_t auth_hdr;
707 } __packed sctp_auth_chunk_t;
708 
709 #endif /* __LINUX_SCTP_H__ */
710