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1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* SCTP kernel reference Implementation
3  * (C) Copyright IBM Corp. 2001, 2004
4  * Copyright (c) 1999-2000 Cisco, Inc.
5  * Copyright (c) 1999-2001 Motorola, Inc.
6  * Copyright (c) 2001 Intel Corp.
7  * Copyright (c) 2001 Nokia, Inc.
8  * Copyright (c) 2001 La Monte H.P. Yarroll
9  *
10  * This file is part of the SCTP kernel reference Implementation
11  *
12  * Various protocol defined structures.
13  *
14  * Please send any bug reports or fixes you make to the
15  * email address(es):
16  *    lksctp developers <linux-sctp@vger.kernel.org>
17  *
18  * Or submit a bug report through the following website:
19  *    http://www.sf.net/projects/lksctp
20  *
21  * Written or modified by:
22  *    La Monte H.P. Yarroll <piggy@acm.org>
23  *    Karl Knutson <karl@athena.chicago.il.us>
24  *    Jon Grimm <jgrimm@us.ibm.com>
25  *    Xingang Guo <xingang.guo@intel.com>
26  *    randall@sctp.chicago.il.us
27  *    kmorneau@cisco.com
28  *    qxie1@email.mot.com
29  *    Sridhar Samudrala <sri@us.ibm.com>
30  *    Kevin Gao <kevin.gao@intel.com>
31  *
32  * Any bugs reported given to us we will try to fix... any fixes shared will
33  * be incorporated into the next SCTP release.
34  */
35 #ifndef __LINUX_SCTP_H__
36 #define __LINUX_SCTP_H__
37 
38 #include <linux/in.h>		/* We need in_addr.  */
39 #include <linux/in6.h>		/* We need in6_addr.  */
40 #include <linux/skbuff.h>
41 
42 #include <uapi/linux/sctp.h>
43 
44 /* Section 3.1.  SCTP Common Header Format */
45 struct sctphdr {
46 	__be16 source;
47 	__be16 dest;
48 	__be32 vtag;
49 	__le32 checksum;
50 };
51 
sctp_hdr(const struct sk_buff * skb)52 static inline struct sctphdr *sctp_hdr(const struct sk_buff *skb)
53 {
54 	return (struct sctphdr *)skb_transport_header(skb);
55 }
56 
57 /* Section 3.2.  Chunk Field Descriptions. */
58 struct sctp_chunkhdr {
59 	__u8 type;
60 	__u8 flags;
61 	__be16 length;
62 };
63 
64 
65 /* Section 3.2.  Chunk Type Values.
66  * [Chunk Type] identifies the type of information contained in the Chunk
67  * Value field. It takes a value from 0 to 254. The value of 255 is
68  * reserved for future use as an extension field.
69  */
70 enum sctp_cid {
71 	SCTP_CID_DATA			= 0,
72         SCTP_CID_INIT			= 1,
73         SCTP_CID_INIT_ACK		= 2,
74         SCTP_CID_SACK			= 3,
75         SCTP_CID_HEARTBEAT		= 4,
76         SCTP_CID_HEARTBEAT_ACK		= 5,
77         SCTP_CID_ABORT			= 6,
78         SCTP_CID_SHUTDOWN		= 7,
79         SCTP_CID_SHUTDOWN_ACK		= 8,
80         SCTP_CID_ERROR			= 9,
81         SCTP_CID_COOKIE_ECHO		= 10,
82         SCTP_CID_COOKIE_ACK	        = 11,
83         SCTP_CID_ECN_ECNE		= 12,
84         SCTP_CID_ECN_CWR		= 13,
85         SCTP_CID_SHUTDOWN_COMPLETE	= 14,
86 
87 	/* AUTH Extension Section 4.1 */
88 	SCTP_CID_AUTH			= 0x0F,
89 
90 	/* sctp ndata 5.1. I-DATA */
91 	SCTP_CID_I_DATA			= 0x40,
92 
93 	/* PR-SCTP Sec 3.2 */
94 	SCTP_CID_FWD_TSN		= 0xC0,
95 
96 	/* Use hex, as defined in ADDIP sec. 3.1 */
97 	SCTP_CID_ASCONF			= 0xC1,
98 	SCTP_CID_I_FWD_TSN		= 0xC2,
99 	SCTP_CID_ASCONF_ACK		= 0x80,
100 	SCTP_CID_RECONF			= 0x82,
101 }; /* enum */
102 
103 
104 /* Section 3.2
105  *  Chunk Types are encoded such that the highest-order two bits specify
106  *  the action that must be taken if the processing endpoint does not
107  *  recognize the Chunk Type.
108  */
109 enum {
110 	SCTP_CID_ACTION_DISCARD     = 0x00,
111 	SCTP_CID_ACTION_DISCARD_ERR = 0x40,
112 	SCTP_CID_ACTION_SKIP        = 0x80,
113 	SCTP_CID_ACTION_SKIP_ERR    = 0xc0,
114 };
115 
116 enum { SCTP_CID_ACTION_MASK = 0xc0, };
117 
118 /* This flag is used in Chunk Flags for ABORT and SHUTDOWN COMPLETE.
119  *
120  * 3.3.7 Abort Association (ABORT) (6):
121  *    The T bit is set to 0 if the sender had a TCB that it destroyed.
122  *    If the sender did not have a TCB it should set this bit to 1.
123  */
124 enum { SCTP_CHUNK_FLAG_T = 0x01 };
125 
126 /*
127  *  Set the T bit
128  *
129  *      0                   1                   2                   3
130  *      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
131  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
132  *     |   Type = 14   |Reserved     |T|      Length = 4               |
133  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
134  *
135  * Chunk Flags: 8 bits
136  *
137  *   Reserved:  7 bits
138  *     Set to 0 on transmit and ignored on receipt.
139  *
140  *   T bit:  1 bit
141  *     The T bit is set to 0 if the sender had a TCB that it destroyed. If
142  *     the sender did NOT have a TCB it should set this bit to 1.
143  *
144  * Note: Special rules apply to this chunk for verification, please
145  * see Section 8.5.1 for details.
146  */
147 
148 #define sctp_test_T_bit(c)    ((c)->chunk_hdr->flags & SCTP_CHUNK_FLAG_T)
149 
150 /* RFC 2960
151  * Section 3.2.1 Optional/Variable-length Parmaeter Format.
152  */
153 
154 struct sctp_paramhdr {
155 	__be16 type;
156 	__be16 length;
157 };
158 
159 enum sctp_param {
160 
161 	/* RFC 2960 Section 3.3.5 */
162 	SCTP_PARAM_HEARTBEAT_INFO		= cpu_to_be16(1),
163 	/* RFC 2960 Section 3.3.2.1 */
164 	SCTP_PARAM_IPV4_ADDRESS			= cpu_to_be16(5),
165 	SCTP_PARAM_IPV6_ADDRESS			= cpu_to_be16(6),
166 	SCTP_PARAM_STATE_COOKIE			= cpu_to_be16(7),
167 	SCTP_PARAM_UNRECOGNIZED_PARAMETERS	= cpu_to_be16(8),
168 	SCTP_PARAM_COOKIE_PRESERVATIVE		= cpu_to_be16(9),
169 	SCTP_PARAM_HOST_NAME_ADDRESS		= cpu_to_be16(11),
170 	SCTP_PARAM_SUPPORTED_ADDRESS_TYPES	= cpu_to_be16(12),
171 	SCTP_PARAM_ECN_CAPABLE			= cpu_to_be16(0x8000),
172 
173 	/* AUTH Extension Section 3 */
174 	SCTP_PARAM_RANDOM			= cpu_to_be16(0x8002),
175 	SCTP_PARAM_CHUNKS			= cpu_to_be16(0x8003),
176 	SCTP_PARAM_HMAC_ALGO			= cpu_to_be16(0x8004),
177 
178 	/* Add-IP: Supported Extensions, Section 4.2 */
179 	SCTP_PARAM_SUPPORTED_EXT	= cpu_to_be16(0x8008),
180 
181 	/* PR-SCTP Sec 3.1 */
182 	SCTP_PARAM_FWD_TSN_SUPPORT	= cpu_to_be16(0xc000),
183 
184 	/* Add-IP Extension. Section 3.2 */
185 	SCTP_PARAM_ADD_IP		= cpu_to_be16(0xc001),
186 	SCTP_PARAM_DEL_IP		= cpu_to_be16(0xc002),
187 	SCTP_PARAM_ERR_CAUSE		= cpu_to_be16(0xc003),
188 	SCTP_PARAM_SET_PRIMARY		= cpu_to_be16(0xc004),
189 	SCTP_PARAM_SUCCESS_REPORT	= cpu_to_be16(0xc005),
190 	SCTP_PARAM_ADAPTATION_LAYER_IND = cpu_to_be16(0xc006),
191 
192 	/* RE-CONFIG. Section 4 */
193 	SCTP_PARAM_RESET_OUT_REQUEST		= cpu_to_be16(0x000d),
194 	SCTP_PARAM_RESET_IN_REQUEST		= cpu_to_be16(0x000e),
195 	SCTP_PARAM_RESET_TSN_REQUEST		= cpu_to_be16(0x000f),
196 	SCTP_PARAM_RESET_RESPONSE		= cpu_to_be16(0x0010),
197 	SCTP_PARAM_RESET_ADD_OUT_STREAMS	= cpu_to_be16(0x0011),
198 	SCTP_PARAM_RESET_ADD_IN_STREAMS		= cpu_to_be16(0x0012),
199 }; /* enum */
200 
201 
202 /* RFC 2960 Section 3.2.1
203  *  The Parameter Types are encoded such that the highest-order two bits
204  *  specify the action that must be taken if the processing endpoint does
205  *  not recognize the Parameter Type.
206  *
207  */
208 enum {
209 	SCTP_PARAM_ACTION_DISCARD     = cpu_to_be16(0x0000),
210 	SCTP_PARAM_ACTION_DISCARD_ERR = cpu_to_be16(0x4000),
211 	SCTP_PARAM_ACTION_SKIP        = cpu_to_be16(0x8000),
212 	SCTP_PARAM_ACTION_SKIP_ERR    = cpu_to_be16(0xc000),
213 };
214 
215 enum { SCTP_PARAM_ACTION_MASK = cpu_to_be16(0xc000), };
216 
217 /* RFC 2960 Section 3.3.1 Payload Data (DATA) (0) */
218 
219 struct sctp_datahdr {
220 	__be32 tsn;
221 	__be16 stream;
222 	__be16 ssn;
223 	__u32 ppid;
224 	__u8  payload[];
225 };
226 
227 struct sctp_data_chunk {
228 	struct sctp_chunkhdr chunk_hdr;
229 	struct sctp_datahdr data_hdr;
230 };
231 
232 struct sctp_idatahdr {
233 	__be32 tsn;
234 	__be16 stream;
235 	__be16 reserved;
236 	__be32 mid;
237 	union {
238 		__u32 ppid;
239 		__be32 fsn;
240 	};
241 	__u8 payload[0];
242 };
243 
244 struct sctp_idata_chunk {
245 	struct sctp_chunkhdr chunk_hdr;
246 	struct sctp_idatahdr data_hdr;
247 };
248 
249 /* DATA Chuck Specific Flags */
250 enum {
251 	SCTP_DATA_MIDDLE_FRAG	= 0x00,
252 	SCTP_DATA_LAST_FRAG	= 0x01,
253 	SCTP_DATA_FIRST_FRAG	= 0x02,
254 	SCTP_DATA_NOT_FRAG	= 0x03,
255 	SCTP_DATA_UNORDERED	= 0x04,
256 	SCTP_DATA_SACK_IMM	= 0x08,
257 };
258 enum { SCTP_DATA_FRAG_MASK = 0x03, };
259 
260 
261 /* RFC 2960 Section 3.3.2 Initiation (INIT) (1)
262  *
263  *  This chunk is used to initiate a SCTP association between two
264  *  endpoints.
265  */
266 struct sctp_inithdr {
267 	__be32 init_tag;
268 	__be32 a_rwnd;
269 	__be16 num_outbound_streams;
270 	__be16 num_inbound_streams;
271 	__be32 initial_tsn;
272 	__u8  params[];
273 };
274 
275 struct sctp_init_chunk {
276 	struct sctp_chunkhdr chunk_hdr;
277 	struct sctp_inithdr init_hdr;
278 };
279 
280 
281 /* Section 3.3.2.1. IPv4 Address Parameter (5) */
282 struct sctp_ipv4addr_param {
283 	struct sctp_paramhdr param_hdr;
284 	struct in_addr addr;
285 };
286 
287 /* Section 3.3.2.1. IPv6 Address Parameter (6) */
288 struct sctp_ipv6addr_param {
289 	struct sctp_paramhdr param_hdr;
290 	struct in6_addr addr;
291 };
292 
293 /* Section 3.3.2.1 Cookie Preservative (9) */
294 struct sctp_cookie_preserve_param {
295 	struct sctp_paramhdr param_hdr;
296 	__be32 lifespan_increment;
297 };
298 
299 /* Section 3.3.2.1 Host Name Address (11) */
300 struct sctp_hostname_param {
301 	struct sctp_paramhdr param_hdr;
302 	uint8_t hostname[];
303 };
304 
305 /* Section 3.3.2.1 Supported Address Types (12) */
306 struct sctp_supported_addrs_param {
307 	struct sctp_paramhdr param_hdr;
308 	__be16 types[];
309 };
310 
311 /* ADDIP Section 3.2.6 Adaptation Layer Indication */
312 struct sctp_adaptation_ind_param {
313 	struct sctp_paramhdr param_hdr;
314 	__be32 adaptation_ind;
315 };
316 
317 /* ADDIP Section 4.2.7 Supported Extensions Parameter */
318 struct sctp_supported_ext_param {
319 	struct sctp_paramhdr param_hdr;
320 	__u8 chunks[];
321 };
322 
323 /* AUTH Section 3.1 Random */
324 struct sctp_random_param {
325 	struct sctp_paramhdr param_hdr;
326 	__u8 random_val[];
327 };
328 
329 /* AUTH Section 3.2 Chunk List */
330 struct sctp_chunks_param {
331 	struct sctp_paramhdr param_hdr;
332 	__u8 chunks[];
333 };
334 
335 /* AUTH Section 3.3 HMAC Algorithm */
336 struct sctp_hmac_algo_param {
337 	struct sctp_paramhdr param_hdr;
338 	__be16 hmac_ids[];
339 };
340 
341 /* RFC 2960.  Section 3.3.3 Initiation Acknowledgement (INIT ACK) (2):
342  *   The INIT ACK chunk is used to acknowledge the initiation of an SCTP
343  *   association.
344  */
345 struct sctp_initack_chunk {
346 	struct sctp_chunkhdr chunk_hdr;
347 	struct sctp_inithdr init_hdr;
348 };
349 
350 /* Section 3.3.3.1 State Cookie (7) */
351 struct sctp_cookie_param {
352 	struct sctp_paramhdr p;
353 	__u8 body[];
354 };
355 
356 /* Section 3.3.3.1 Unrecognized Parameters (8) */
357 struct sctp_unrecognized_param {
358 	struct sctp_paramhdr param_hdr;
359 	struct sctp_paramhdr unrecognized;
360 };
361 
362 
363 
364 /*
365  * 3.3.4 Selective Acknowledgement (SACK) (3):
366  *
367  *  This chunk is sent to the peer endpoint to acknowledge received DATA
368  *  chunks and to inform the peer endpoint of gaps in the received
369  *  subsequences of DATA chunks as represented by their TSNs.
370  */
371 
372 struct sctp_gap_ack_block {
373 	__be16 start;
374 	__be16 end;
375 };
376 
377 union sctp_sack_variable {
378 	struct sctp_gap_ack_block gab;
379 	__be32 dup;
380 };
381 
382 struct sctp_sackhdr {
383 	__be32 cum_tsn_ack;
384 	__be32 a_rwnd;
385 	__be16 num_gap_ack_blocks;
386 	__be16 num_dup_tsns;
387 	union sctp_sack_variable variable[];
388 };
389 
390 struct sctp_sack_chunk {
391 	struct sctp_chunkhdr chunk_hdr;
392 	struct sctp_sackhdr sack_hdr;
393 };
394 
395 
396 /* RFC 2960.  Section 3.3.5 Heartbeat Request (HEARTBEAT) (4):
397  *
398  *  An endpoint should send this chunk to its peer endpoint to probe the
399  *  reachability of a particular destination transport address defined in
400  *  the present association.
401  */
402 
403 struct sctp_heartbeathdr {
404 	struct sctp_paramhdr info;
405 };
406 
407 struct sctp_heartbeat_chunk {
408 	struct sctp_chunkhdr chunk_hdr;
409 	struct sctp_heartbeathdr hb_hdr;
410 };
411 
412 
413 /* For the abort and shutdown ACK we must carry the init tag in the
414  * common header. Just the common header is all that is needed with a
415  * chunk descriptor.
416  */
417 struct sctp_abort_chunk {
418 	struct sctp_chunkhdr uh;
419 };
420 
421 
422 /* For the graceful shutdown we must carry the tag (in common header)
423  * and the highest consecutive acking value.
424  */
425 struct sctp_shutdownhdr {
426 	__be32 cum_tsn_ack;
427 };
428 
429 struct sctp_shutdown_chunk {
430 	struct sctp_chunkhdr chunk_hdr;
431 	struct sctp_shutdownhdr shutdown_hdr;
432 };
433 
434 /* RFC 2960.  Section 3.3.10 Operation Error (ERROR) (9) */
435 
436 struct sctp_errhdr {
437 	__be16 cause;
438 	__be16 length;
439 	__u8  variable[];
440 };
441 
442 struct sctp_operr_chunk {
443 	struct sctp_chunkhdr chunk_hdr;
444 	struct sctp_errhdr err_hdr;
445 };
446 
447 /* RFC 2960 3.3.10 - Operation Error
448  *
449  * Cause Code: 16 bits (unsigned integer)
450  *
451  *     Defines the type of error conditions being reported.
452  *    Cause Code
453  *     Value           Cause Code
454  *     ---------      ----------------
455  *      1              Invalid Stream Identifier
456  *      2              Missing Mandatory Parameter
457  *      3              Stale Cookie Error
458  *      4              Out of Resource
459  *      5              Unresolvable Address
460  *      6              Unrecognized Chunk Type
461  *      7              Invalid Mandatory Parameter
462  *      8              Unrecognized Parameters
463  *      9              No User Data
464  *     10              Cookie Received While Shutting Down
465  */
466 enum sctp_error {
467 
468 	SCTP_ERROR_NO_ERROR	   = cpu_to_be16(0x00),
469 	SCTP_ERROR_INV_STRM	   = cpu_to_be16(0x01),
470 	SCTP_ERROR_MISS_PARAM 	   = cpu_to_be16(0x02),
471 	SCTP_ERROR_STALE_COOKIE	   = cpu_to_be16(0x03),
472 	SCTP_ERROR_NO_RESOURCE 	   = cpu_to_be16(0x04),
473 	SCTP_ERROR_DNS_FAILED      = cpu_to_be16(0x05),
474 	SCTP_ERROR_UNKNOWN_CHUNK   = cpu_to_be16(0x06),
475 	SCTP_ERROR_INV_PARAM       = cpu_to_be16(0x07),
476 	SCTP_ERROR_UNKNOWN_PARAM   = cpu_to_be16(0x08),
477 	SCTP_ERROR_NO_DATA         = cpu_to_be16(0x09),
478 	SCTP_ERROR_COOKIE_IN_SHUTDOWN = cpu_to_be16(0x0a),
479 
480 
481 	/* SCTP Implementation Guide:
482 	 *  11  Restart of an association with new addresses
483 	 *  12  User Initiated Abort
484 	 *  13  Protocol Violation
485 	 */
486 
487 	SCTP_ERROR_RESTART         = cpu_to_be16(0x0b),
488 	SCTP_ERROR_USER_ABORT      = cpu_to_be16(0x0c),
489 	SCTP_ERROR_PROTO_VIOLATION = cpu_to_be16(0x0d),
490 
491 	/* ADDIP Section 3.3  New Error Causes
492 	 *
493 	 * Four new Error Causes are added to the SCTP Operational Errors,
494 	 * primarily for use in the ASCONF-ACK chunk.
495 	 *
496 	 * Value          Cause Code
497 	 * ---------      ----------------
498 	 * 0x00A0          Request to Delete Last Remaining IP Address.
499 	 * 0x00A1          Operation Refused Due to Resource Shortage.
500 	 * 0x00A2          Request to Delete Source IP Address.
501 	 * 0x00A3          Association Aborted due to illegal ASCONF-ACK
502 	 * 0x00A4          Request refused - no authorization.
503 	 */
504 	SCTP_ERROR_DEL_LAST_IP	= cpu_to_be16(0x00A0),
505 	SCTP_ERROR_RSRC_LOW	= cpu_to_be16(0x00A1),
506 	SCTP_ERROR_DEL_SRC_IP	= cpu_to_be16(0x00A2),
507 	SCTP_ERROR_ASCONF_ACK   = cpu_to_be16(0x00A3),
508 	SCTP_ERROR_REQ_REFUSED	= cpu_to_be16(0x00A4),
509 
510 	/* AUTH Section 4.  New Error Cause
511 	 *
512 	 * This section defines a new error cause that will be sent if an AUTH
513 	 * chunk is received with an unsupported HMAC identifier.
514 	 * illustrates the new error cause.
515 	 *
516 	 * Cause Code      Error Cause Name
517 	 * --------------------------------------------------------------
518 	 * 0x0105          Unsupported HMAC Identifier
519 	 */
520 	 SCTP_ERROR_UNSUP_HMAC	= cpu_to_be16(0x0105)
521 };
522 
523 
524 
525 /* RFC 2960.  Appendix A.  Explicit Congestion Notification.
526  *   Explicit Congestion Notification Echo (ECNE) (12)
527  */
528 struct sctp_ecnehdr {
529 	__be32 lowest_tsn;
530 };
531 
532 struct sctp_ecne_chunk {
533 	struct sctp_chunkhdr chunk_hdr;
534 	struct sctp_ecnehdr ence_hdr;
535 };
536 
537 /* RFC 2960.  Appendix A.  Explicit Congestion Notification.
538  *   Congestion Window Reduced (CWR) (13)
539  */
540 struct sctp_cwrhdr {
541 	__be32 lowest_tsn;
542 };
543 
544 /* PR-SCTP
545  * 3.2 Forward Cumulative TSN Chunk Definition (FORWARD TSN)
546  *
547  * Forward Cumulative TSN chunk has the following format:
548  *
549  *        0                   1                   2                   3
550  *        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
551  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
552  *      |   Type = 192  |  Flags = 0x00 |        Length = Variable      |
553  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
554  *      |                      New Cumulative TSN                       |
555  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
556  *      |         Stream-1              |       Stream Sequence-1       |
557  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
558  *      \                                                               /
559  *      /                                                               \
560  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
561  *      |         Stream-N              |       Stream Sequence-N       |
562  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
563  *
564  *      Chunk Flags:
565  *
566  *        Set to all zeros on transmit and ignored on receipt.
567  *
568  *      New Cumulative TSN: 32 bit u_int
569  *
570  *       This indicates the new cumulative TSN to the data receiver. Upon
571  *       the reception of this value, the data receiver MUST consider
572  *       any missing TSNs earlier than or equal to this value as received
573  *       and stop reporting them as gaps in any subsequent SACKs.
574  *
575  *      Stream-N: 16 bit u_int
576  *
577  *       This field holds a stream number that was skipped by this
578  *       FWD-TSN.
579  *
580  *      Stream Sequence-N: 16 bit u_int
581  *       This field holds the sequence number associated with the stream
582  *       that was skipped. The stream sequence field holds the largest stream
583  *       sequence number in this stream being skipped.  The receiver of
584  *       the FWD-TSN's can use the Stream-N and Stream Sequence-N fields
585  *       to enable delivery of any stranded TSN's that remain on the stream
586  *       re-ordering queues. This field MUST NOT report TSN's corresponding
587  *       to DATA chunk that are marked as unordered. For ordered DATA
588  *       chunks this field MUST be filled in.
589  */
590 struct sctp_fwdtsn_skip {
591 	__be16 stream;
592 	__be16 ssn;
593 };
594 
595 struct sctp_fwdtsn_hdr {
596 	__be32 new_cum_tsn;
597 	struct sctp_fwdtsn_skip skip[];
598 };
599 
600 struct sctp_fwdtsn_chunk {
601 	struct sctp_chunkhdr chunk_hdr;
602 	struct sctp_fwdtsn_hdr fwdtsn_hdr;
603 };
604 
605 struct sctp_ifwdtsn_skip {
606 	__be16 stream;
607 	__u8 reserved;
608 	__u8 flags;
609 	__be32 mid;
610 };
611 
612 struct sctp_ifwdtsn_hdr {
613 	__be32 new_cum_tsn;
614 	struct sctp_ifwdtsn_skip skip[];
615 };
616 
617 struct sctp_ifwdtsn_chunk {
618 	struct sctp_chunkhdr chunk_hdr;
619 	struct sctp_ifwdtsn_hdr fwdtsn_hdr;
620 };
621 
622 /* ADDIP
623  * Section 3.1.1 Address Configuration Change Chunk (ASCONF)
624  *
625  * 	Serial Number: 32 bits (unsigned integer)
626  *	This value represents a Serial Number for the ASCONF Chunk. The
627  *	valid range of Serial Number is from 0 to 2^32-1.
628  *	Serial Numbers wrap back to 0 after reaching 2^32 -1.
629  *
630  *	Address Parameter: 8 or 20 bytes (depending on type)
631  *	The address is an address of the sender of the ASCONF chunk,
632  *	the address MUST be considered part of the association by the
633  *	peer endpoint. This field may be used by the receiver of the
634  *	ASCONF to help in finding the association. This parameter MUST
635  *	be present in every ASCONF message i.e. it is a mandatory TLV
636  *	parameter.
637  *
638  *	ASCONF Parameter: TLV format
639  *	Each Address configuration change is represented by a TLV
640  *	parameter as defined in Section 3.2. One or more requests may
641  *	be present in an ASCONF Chunk.
642  *
643  * Section 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
644  *
645  *	Serial Number: 32 bits (unsigned integer)
646  *	This value represents the Serial Number for the received ASCONF
647  *	Chunk that is acknowledged by this chunk. This value is copied
648  *	from the received ASCONF Chunk.
649  *
650  *	ASCONF Parameter Response: TLV format
651  *	The ASCONF Parameter Response is used in the ASCONF-ACK to
652  *	report status of ASCONF processing.
653  */
654 struct sctp_addip_param {
655 	struct sctp_paramhdr param_hdr;
656 	__be32 crr_id;
657 };
658 
659 struct sctp_addiphdr {
660 	__be32	serial;
661 	__u8	params[];
662 };
663 
664 struct sctp_addip_chunk {
665 	struct sctp_chunkhdr chunk_hdr;
666 	struct sctp_addiphdr addip_hdr;
667 };
668 
669 /* AUTH
670  * Section 4.1  Authentication Chunk (AUTH)
671  *
672  *   This chunk is used to hold the result of the HMAC calculation.
673  *
674  *    0                   1                   2                   3
675  *    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
676  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
677  *   | Type = 0x0F   |   Flags=0     |             Length            |
678  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
679  *   |     Shared Key Identifier     |   HMAC Identifier             |
680  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
681  *   |                                                               |
682  *   \                             HMAC                              /
683  *   /                                                               \
684  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
685  *
686  *   Type: 1 byte (unsigned integer)
687  *   	This value MUST be set to 0x0F for  all AUTH-chunks.
688  *
689  *   Flags: 1 byte (unsigned integer)
690  *	Set to zero on transmit and ignored on receipt.
691  *
692  *   Length: 2 bytes (unsigned integer)
693  *   	This value holds the length of the HMAC in bytes plus 8.
694  *
695  *  Shared Key Identifier: 2 bytes (unsigned integer)
696  *	This value describes which endpoint pair shared key is used.
697  *
698  *   HMAC Identifier: 2 bytes (unsigned integer)
699  *   	This value describes which message digest is being used.  Table 2
700  *	shows the currently defined values.
701  *
702  *    The following Table 2 shows the currently defined values for HMAC
703  *       identifiers.
704  *
705  *	 +-----------------+--------------------------+
706  *	 | HMAC Identifier | Message Digest Algorithm |
707  *	 +-----------------+--------------------------+
708  *	 | 0               | Reserved                 |
709  *	 | 1               | SHA-1 defined in [8]     |
710  *	 | 2               | Reserved                 |
711  *	 | 3               | SHA-256 defined in [8]   |
712  *	 +-----------------+--------------------------+
713  *
714  *
715  *   HMAC: n bytes (unsigned integer) This hold the result of the HMAC
716  *      calculation.
717  */
718 struct sctp_authhdr {
719 	__be16 shkey_id;
720 	__be16 hmac_id;
721 	__u8   hmac[];
722 };
723 
724 struct sctp_auth_chunk {
725 	struct sctp_chunkhdr chunk_hdr;
726 	struct sctp_authhdr auth_hdr;
727 };
728 
729 struct sctp_infox {
730 	struct sctp_info *sctpinfo;
731 	struct sctp_association *asoc;
732 };
733 
734 struct sctp_reconf_chunk {
735 	struct sctp_chunkhdr chunk_hdr;
736 	__u8 params[];
737 };
738 
739 struct sctp_strreset_outreq {
740 	struct sctp_paramhdr param_hdr;
741 	__be32 request_seq;
742 	__be32 response_seq;
743 	__be32 send_reset_at_tsn;
744 	__be16 list_of_streams[];
745 };
746 
747 struct sctp_strreset_inreq {
748 	struct sctp_paramhdr param_hdr;
749 	__be32 request_seq;
750 	__be16 list_of_streams[];
751 };
752 
753 struct sctp_strreset_tsnreq {
754 	struct sctp_paramhdr param_hdr;
755 	__be32 request_seq;
756 };
757 
758 struct sctp_strreset_addstrm {
759 	struct sctp_paramhdr param_hdr;
760 	__be32 request_seq;
761 	__be16 number_of_streams;
762 	__be16 reserved;
763 };
764 
765 enum {
766 	SCTP_STRRESET_NOTHING_TO_DO	= 0x00,
767 	SCTP_STRRESET_PERFORMED		= 0x01,
768 	SCTP_STRRESET_DENIED		= 0x02,
769 	SCTP_STRRESET_ERR_WRONG_SSN	= 0x03,
770 	SCTP_STRRESET_ERR_IN_PROGRESS	= 0x04,
771 	SCTP_STRRESET_ERR_BAD_SEQNO	= 0x05,
772 	SCTP_STRRESET_IN_PROGRESS	= 0x06,
773 };
774 
775 struct sctp_strreset_resp {
776 	struct sctp_paramhdr param_hdr;
777 	__be32 response_seq;
778 	__be32 result;
779 };
780 
781 struct sctp_strreset_resptsn {
782 	struct sctp_paramhdr param_hdr;
783 	__be32 response_seq;
784 	__be32 result;
785 	__be32 senders_next_tsn;
786 	__be32 receivers_next_tsn;
787 };
788 
789 enum {
790 	SCTP_DSCP_SET_MASK = 0x1,
791 	SCTP_DSCP_VAL_MASK = 0xfc,
792 	SCTP_FLOWLABEL_SET_MASK = 0x100000,
793 	SCTP_FLOWLABEL_VAL_MASK = 0xfffff
794 };
795 
796 #endif /* __LINUX_SCTP_H__ */
797