xref: /freebsd/sys/netinet/sctp_header.h (revision 7ef62cebc2f965b0f640263e179276928885e33d)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 2001-2007, by Cisco Systems, Inc. All rights reserved.
5  * Copyright (c) 2008-2012, by Randall Stewart. All rights reserved.
6  * Copyright (c) 2008-2012, by Michael Tuexen. All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions are met:
10  *
11  * a) Redistributions of source code must retain the above copyright notice,
12  *    this list of conditions and the following disclaimer.
13  *
14  * b) Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in
16  *    the documentation and/or other materials provided with the distribution.
17  *
18  * c) Neither the name of Cisco Systems, Inc. nor the names of its
19  *    contributors may be used to endorse or promote products derived
20  *    from this software without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
24  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
26  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
27  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
28  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
29  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
30  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
31  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
32  * THE POSSIBILITY OF SUCH DAMAGE.
33  */
34 
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 #ifndef _NETINET_SCTP_HEADER_H_
39 #define _NETINET_SCTP_HEADER_H_
40 
41 #include <sys/time.h>
42 #include <netinet/sctp.h>
43 #include <netinet/sctp_constants.h>
44 
45 #define SCTP_PACKED __attribute__((packed))
46 
47 /*
48  * Parameter structures
49  */
50 struct sctp_ipv4addr_param {
51 	struct sctp_paramhdr ph;	/* type=SCTP_IPV4_PARAM_TYPE, len=8 */
52 	uint32_t addr;		/* IPV4 address */
53 }                   SCTP_PACKED;
54 
55 #define SCTP_V6_ADDR_BYTES 16
56 
57 struct sctp_ipv6addr_param {
58 	struct sctp_paramhdr ph;	/* type=SCTP_IPV6_PARAM_TYPE, len=20 */
59 	uint8_t addr[SCTP_V6_ADDR_BYTES];	/* IPV6 address */
60 }                   SCTP_PACKED;
61 
62 /* Cookie Preservative */
63 struct sctp_cookie_perserve_param {
64 	struct sctp_paramhdr ph;	/* type=SCTP_COOKIE_PRESERVE, len=8 */
65 	uint32_t time;		/* time in ms to extend cookie */
66 }                          SCTP_PACKED;
67 
68 #define SCTP_ARRAY_MIN_LEN 1
69 /* Host Name Address */
70 struct sctp_host_name_param {
71 	struct sctp_paramhdr ph;	/* type=SCTP_HOSTNAME_ADDRESS */
72 	char name[SCTP_ARRAY_MIN_LEN];	/* host name */
73 }                    SCTP_PACKED;
74 
75 /*
76  * This is the maximum padded size of a s-a-p
77  * so paramheadr + 3 address types (6 bytes) + 2 byte pad = 12
78  */
79 #define SCTP_MAX_ADDR_PARAMS_SIZE 12
80 /* supported address type */
81 struct sctp_supported_addr_param {
82 	struct sctp_paramhdr ph;	/* type=SCTP_SUPPORTED_ADDRTYPE */
83 	uint16_t addr_type[2];	/* array of supported address types */
84 }                         SCTP_PACKED;
85 
86 /* heartbeat info parameter */
87 struct sctp_heartbeat_info_param {
88 	struct sctp_paramhdr ph;
89 	uint32_t time_value_1;
90 	uint32_t time_value_2;
91 	uint32_t random_value1;
92 	uint32_t random_value2;
93 	uint8_t addr_family;
94 	uint8_t addr_len;
95 	/* make sure that this structure is 4 byte aligned */
96 	uint8_t padding[2];
97 	char address[SCTP_ADDRMAX];
98 }                         SCTP_PACKED;
99 
100 /* draft-ietf-tsvwg-prsctp */
101 /* PR-SCTP supported parameter */
102 struct sctp_prsctp_supported_param {
103 	struct sctp_paramhdr ph;
104 }                           SCTP_PACKED;
105 
106 /* draft-ietf-tsvwg-addip-sctp */
107 struct sctp_asconf_paramhdr {	/* an ASCONF "parameter" */
108 	struct sctp_paramhdr ph;	/* a SCTP parameter header */
109 	uint32_t correlation_id;	/* correlation id for this param */
110 }                    SCTP_PACKED;
111 
112 struct sctp_asconf_addr_param {	/* an ASCONF address parameter */
113 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
114 	struct sctp_ipv6addr_param addrp;	/* max storage size */
115 }                      SCTP_PACKED;
116 
117 struct sctp_asconf_tag_param {	/* an ASCONF NAT-Vtag parameter */
118 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
119 	uint32_t local_vtag;
120 	uint32_t remote_vtag;
121 }                     SCTP_PACKED;
122 
123 struct sctp_asconf_addrv4_param {	/* an ASCONF address (v4) parameter */
124 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
125 	struct sctp_ipv4addr_param addrp;	/* max storage size */
126 }                        SCTP_PACKED;
127 
128 #define SCTP_MAX_SUPPORTED_EXT 256
129 
130 struct sctp_supported_chunk_types_param {
131 	struct sctp_paramhdr ph;	/* type = 0x8008  len = x */
132 	uint8_t chunk_types[];
133 }                                SCTP_PACKED;
134 
135 /*
136  * Structures for DATA chunks
137  */
138 struct sctp_data {
139 	uint32_t tsn;
140 	uint16_t sid;
141 	uint16_t ssn;
142 	uint32_t ppid;
143 	/* user data follows */
144 }         SCTP_PACKED;
145 
146 struct sctp_data_chunk {
147 	struct sctp_chunkhdr ch;
148 	struct sctp_data dp;
149 }               SCTP_PACKED;
150 
151 struct sctp_idata {
152 	uint32_t tsn;
153 	uint16_t sid;
154 	uint16_t reserved;	/* Where does the SSN go? */
155 	uint32_t mid;
156 	union {
157 		uint32_t ppid;
158 		uint32_t fsn;	/* Fragment Sequence Number */
159 	}     ppid_fsn;
160 	/* user data follows */
161 }          SCTP_PACKED;
162 
163 struct sctp_idata_chunk {
164 	struct sctp_chunkhdr ch;
165 	struct sctp_idata dp;
166 }                SCTP_PACKED;
167 
168 /*
169  * Structures for the control chunks
170  */
171 
172 /* Initiate (INIT)/Initiate Ack (INIT ACK) */
173 struct sctp_init {
174 	uint32_t initiate_tag;	/* initiate tag */
175 	uint32_t a_rwnd;	/* a_rwnd */
176 	uint16_t num_outbound_streams;	/* OS */
177 	uint16_t num_inbound_streams;	/* MIS */
178 	uint32_t initial_tsn;	/* I-TSN */
179 	/* optional param's follow */
180 }         SCTP_PACKED;
181 #define SCTP_IDENTIFICATION_SIZE 16
182 #define SCTP_ADDRESS_SIZE 4
183 #define SCTP_RESERVE_SPACE 5
184 /* state cookie header */
185 struct sctp_state_cookie {	/* this is our definition... */
186 	uint8_t identification[SCTP_IDENTIFICATION_SIZE];	/* id of who we are */
187 	struct timeval time_entered;	/* the time I built cookie */
188 	uint32_t cookie_life;	/* life I will award this cookie */
189 	uint32_t tie_tag_my_vtag;	/* my tag in old association */
190 
191 	uint32_t tie_tag_peer_vtag;	/* peers tag in old association */
192 	uint32_t peers_vtag;	/* peers tag in INIT (for quick ref) */
193 
194 	uint32_t my_vtag;	/* my tag in INIT-ACK (for quick ref) */
195 	uint32_t address[SCTP_ADDRESS_SIZE];	/* 4 ints/128 bits */
196 	uint32_t addr_type;	/* address type */
197 	uint32_t laddress[SCTP_ADDRESS_SIZE];	/* my local from address */
198 	uint32_t laddr_type;	/* my local from address type */
199 	uint32_t scope_id;	/* v6 scope id for link-locals */
200 
201 	uint16_t peerport;	/* port address of the peer in the INIT */
202 	uint16_t myport;	/* my port address used in the INIT */
203 	uint8_t ipv4_addr_legal;	/* Are V4 addr legal? */
204 	uint8_t ipv6_addr_legal;	/* Are V6 addr legal? */
205 	uint8_t local_scope;	/* IPv6 local scope flag */
206 	uint8_t site_scope;	/* IPv6 site scope flag */
207 
208 	uint8_t ipv4_scope;	/* IPv4 private addr scope */
209 	uint8_t loopback_scope;	/* loopback scope information */
210 	uint8_t rcv_edmid;	/* copy of the inp value */
211 	uint8_t reserved[SCTP_RESERVE_SPACE];	/* Align to 64 bits */
212 	/*
213 	 * at the end is tacked on the INIT chunk and the INIT-ACK chunk
214 	 * (minus the cookie).
215 	 */
216 }                 SCTP_PACKED;
217 
218 /* state cookie parameter */
219 struct sctp_state_cookie_param {
220 	struct sctp_paramhdr ph;
221 	struct sctp_state_cookie cookie;
222 }                       SCTP_PACKED;
223 
224 struct sctp_init_chunk {
225 	struct sctp_chunkhdr ch;
226 	struct sctp_init init;
227 }               SCTP_PACKED;
228 
229 struct sctp_init_msg {
230 	struct sctphdr sh;
231 	struct sctp_init_chunk msg;
232 }             SCTP_PACKED;
233 
234 /* ... used for both INIT and INIT ACK */
235 #define sctp_init_ack		sctp_init
236 #define sctp_init_ack_chunk	sctp_init_chunk
237 #define sctp_init_ack_msg	sctp_init_msg
238 
239 /* Selective Ack (SACK) */
240 struct sctp_gap_ack_block {
241 	uint16_t start;		/* Gap Ack block start */
242 	uint16_t end;		/* Gap Ack block end */
243 }                  SCTP_PACKED;
244 
245 struct sctp_sack {
246 	uint32_t cum_tsn_ack;	/* cumulative TSN Ack */
247 	uint32_t a_rwnd;	/* updated a_rwnd of sender */
248 	uint16_t num_gap_ack_blks;	/* number of Gap Ack blocks */
249 	uint16_t num_dup_tsns;	/* number of duplicate TSNs */
250 	/* struct sctp_gap_ack_block's follow */
251 	/* uint32_t duplicate_tsn's follow */
252 }         SCTP_PACKED;
253 
254 struct sctp_sack_chunk {
255 	struct sctp_chunkhdr ch;
256 	struct sctp_sack sack;
257 }               SCTP_PACKED;
258 
259 struct sctp_nr_sack {
260 	uint32_t cum_tsn_ack;	/* cumulative TSN Ack */
261 	uint32_t a_rwnd;	/* updated a_rwnd of sender */
262 	uint16_t num_gap_ack_blks;	/* number of Gap Ack blocks */
263 	uint16_t num_nr_gap_ack_blks;	/* number of NR Gap Ack blocks */
264 	uint16_t num_dup_tsns;	/* number of duplicate TSNs */
265 	uint16_t reserved;	/* not currently used */
266 	/* struct sctp_gap_ack_block's follow */
267 	/* uint32_t duplicate_tsn's follow */
268 }            SCTP_PACKED;
269 
270 struct sctp_nr_sack_chunk {
271 	struct sctp_chunkhdr ch;
272 	struct sctp_nr_sack nr_sack;
273 }                  SCTP_PACKED;
274 
275 /* Heartbeat Request (HEARTBEAT) */
276 struct sctp_heartbeat {
277 	struct sctp_heartbeat_info_param hb_info;
278 }              SCTP_PACKED;
279 
280 struct sctp_heartbeat_chunk {
281 	struct sctp_chunkhdr ch;
282 	struct sctp_heartbeat heartbeat;
283 }                    SCTP_PACKED;
284 
285 /* ... used for Heartbeat Ack (HEARTBEAT ACK) */
286 #define sctp_heartbeat_ack		sctp_heartbeat
287 #define sctp_heartbeat_ack_chunk	sctp_heartbeat_chunk
288 
289 /* Abort Asssociation (ABORT) */
290 struct sctp_abort_chunk {
291 	struct sctp_chunkhdr ch;
292 	/* optional error cause may follow */
293 }                SCTP_PACKED;
294 
295 struct sctp_abort_msg {
296 	struct sctphdr sh;
297 	struct sctp_abort_chunk msg;
298 }              SCTP_PACKED;
299 
300 /* Shutdown Association (SHUTDOWN) */
301 struct sctp_shutdown_chunk {
302 	struct sctp_chunkhdr ch;
303 	uint32_t cumulative_tsn_ack;
304 }                   SCTP_PACKED;
305 
306 /* Shutdown Acknowledgment (SHUTDOWN ACK) */
307 struct sctp_shutdown_ack_chunk {
308 	struct sctp_chunkhdr ch;
309 }                       SCTP_PACKED;
310 
311 /* Operation Error (ERROR) */
312 struct sctp_error_chunk {
313 	struct sctp_chunkhdr ch;
314 	/* optional error causes follow */
315 }                SCTP_PACKED;
316 
317 /* Cookie Echo (COOKIE ECHO) */
318 struct sctp_cookie_echo_chunk {
319 	struct sctp_chunkhdr ch;
320 	struct sctp_state_cookie cookie;
321 }                      SCTP_PACKED;
322 
323 /* Cookie Acknowledgment (COOKIE ACK) */
324 struct sctp_cookie_ack_chunk {
325 	struct sctp_chunkhdr ch;
326 }                     SCTP_PACKED;
327 
328 /* Explicit Congestion Notification Echo (ECNE) */
329 struct old_sctp_ecne_chunk {
330 	struct sctp_chunkhdr ch;
331 	uint32_t tsn;
332 }                   SCTP_PACKED;
333 
334 struct sctp_ecne_chunk {
335 	struct sctp_chunkhdr ch;
336 	uint32_t tsn;
337 	uint32_t num_pkts_since_cwr;
338 }               SCTP_PACKED;
339 
340 /* Congestion Window Reduced (CWR) */
341 struct sctp_cwr_chunk {
342 	struct sctp_chunkhdr ch;
343 	uint32_t tsn;
344 }              SCTP_PACKED;
345 
346 /* Shutdown Complete (SHUTDOWN COMPLETE) */
347 struct sctp_shutdown_complete_chunk {
348 	struct sctp_chunkhdr ch;
349 }                            SCTP_PACKED;
350 
351 struct sctp_adaptation_layer_indication {
352 	struct sctp_paramhdr ph;
353 	uint32_t indication;
354 }                                SCTP_PACKED;
355 
356 /*
357  * draft-ietf-tsvwg-addip-sctp
358  */
359 /* Address/Stream Configuration Change (ASCONF) */
360 struct sctp_asconf_chunk {
361 	struct sctp_chunkhdr ch;
362 	uint32_t serial_number;
363 	/* lookup address parameter (mandatory) */
364 	/* asconf parameters follow */
365 }                 SCTP_PACKED;
366 
367 /* Address/Stream Configuration Acknowledge (ASCONF ACK) */
368 struct sctp_asconf_ack_chunk {
369 	struct sctp_chunkhdr ch;
370 	uint32_t serial_number;
371 	/* asconf parameters follow */
372 }                     SCTP_PACKED;
373 
374 /* draft-ietf-tsvwg-prsctp */
375 /* Forward Cumulative TSN (FORWARD TSN) */
376 struct sctp_forward_tsn_chunk {
377 	struct sctp_chunkhdr ch;
378 	uint32_t new_cumulative_tsn;
379 	/* stream/sequence pairs (sctp_strseq) follow */
380 }                      SCTP_PACKED;
381 
382 struct sctp_strseq {
383 	uint16_t sid;
384 	uint16_t ssn;
385 }           SCTP_PACKED;
386 
387 struct sctp_strseq_mid {
388 	uint16_t sid;
389 	uint16_t flags;
390 	uint32_t mid;
391 };
392 
393 struct sctp_forward_tsn_msg {
394 	struct sctphdr sh;
395 	struct sctp_forward_tsn_chunk msg;
396 }                    SCTP_PACKED;
397 
398 /* should be a multiple of 4 - 1 aka 3/7/11 etc. */
399 
400 #define SCTP_NUM_DB_TO_VERIFY 31
401 
402 struct sctp_chunk_desc {
403 	uint8_t chunk_type;
404 	uint8_t data_bytes[SCTP_NUM_DB_TO_VERIFY];
405 	uint32_t tsn_ifany;
406 }               SCTP_PACKED;
407 
408 struct sctp_pktdrop_chunk {
409 	struct sctp_chunkhdr ch;
410 	uint32_t bottle_bw;
411 	uint32_t current_onq;
412 	uint16_t trunc_len;
413 	uint16_t reserved;
414 	uint8_t data[];
415 }                  SCTP_PACKED;
416 
417 /**********STREAM RESET STUFF ******************/
418 
419 struct sctp_stream_reset_request {
420 	struct sctp_paramhdr ph;
421 	uint32_t request_seq;
422 }                         SCTP_PACKED;
423 
424 struct sctp_stream_reset_out_request {
425 	struct sctp_paramhdr ph;
426 	uint32_t request_seq;	/* monotonically increasing seq no */
427 	uint32_t response_seq;	/* if a response, the resp seq no */
428 	uint32_t send_reset_at_tsn;	/* last TSN I assigned outbound */
429 	uint16_t list_of_streams[];	/* if not all list of streams */
430 }                             SCTP_PACKED;
431 
432 struct sctp_stream_reset_in_request {
433 	struct sctp_paramhdr ph;
434 	uint32_t request_seq;
435 	uint16_t list_of_streams[];	/* if not all list of streams */
436 }                            SCTP_PACKED;
437 
438 struct sctp_stream_reset_tsn_request {
439 	struct sctp_paramhdr ph;
440 	uint32_t request_seq;
441 }                             SCTP_PACKED;
442 
443 struct sctp_stream_reset_response {
444 	struct sctp_paramhdr ph;
445 	uint32_t response_seq;	/* if a response, the resp seq no */
446 	uint32_t result;
447 }                          SCTP_PACKED;
448 
449 struct sctp_stream_reset_response_tsn {
450 	struct sctp_paramhdr ph;
451 	uint32_t response_seq;	/* if a response, the resp seq no */
452 	uint32_t result;
453 	uint32_t senders_next_tsn;
454 	uint32_t receivers_next_tsn;
455 }                              SCTP_PACKED;
456 
457 struct sctp_stream_reset_add_strm {
458 	struct sctp_paramhdr ph;
459 	uint32_t request_seq;
460 	uint16_t number_of_streams;
461 	uint16_t reserved;
462 }                          SCTP_PACKED;
463 
464 #define SCTP_STREAM_RESET_RESULT_NOTHING_TO_DO   0x00000000	/* XXX: unused */
465 #define SCTP_STREAM_RESET_RESULT_PERFORMED       0x00000001
466 #define SCTP_STREAM_RESET_RESULT_DENIED          0x00000002
467 #define SCTP_STREAM_RESET_RESULT_ERR__WRONG_SSN  0x00000003	/* XXX: unused */
468 #define SCTP_STREAM_RESET_RESULT_ERR_IN_PROGRESS 0x00000004
469 #define SCTP_STREAM_RESET_RESULT_ERR_BAD_SEQNO   0x00000005
470 #define SCTP_STREAM_RESET_RESULT_IN_PROGRESS     0x00000006	/* XXX: unused */
471 
472 /*
473  * convience structures, note that if you are making a request for specific
474  * streams then the request will need to be an overlay structure.
475  */
476 
477 struct sctp_stream_reset_tsn_req {
478 	struct sctp_chunkhdr ch;
479 	struct sctp_stream_reset_tsn_request sr_req;
480 }                         SCTP_PACKED;
481 
482 struct sctp_stream_reset_resp {
483 	struct sctp_chunkhdr ch;
484 	struct sctp_stream_reset_response sr_resp;
485 }                      SCTP_PACKED;
486 
487 /* respone only valid with a TSN request */
488 struct sctp_stream_reset_resp_tsn {
489 	struct sctp_chunkhdr ch;
490 	struct sctp_stream_reset_response_tsn sr_resp;
491 }                          SCTP_PACKED;
492 
493 /****************************************************/
494 
495 /*
496  * Authenticated chunks support draft-ietf-tsvwg-sctp-auth
497  */
498 
499 /* Should we make the max be 32? */
500 #define SCTP_RANDOM_MAX_SIZE 256
501 struct sctp_auth_random {
502 	struct sctp_paramhdr ph;	/* type = 0x8002 */
503 	uint8_t random_data[];
504 }                SCTP_PACKED;
505 
506 struct sctp_auth_chunk_list {
507 	struct sctp_paramhdr ph;	/* type = 0x8003 */
508 	uint8_t chunk_types[];
509 }                    SCTP_PACKED;
510 
511 struct sctp_auth_hmac_algo {
512 	struct sctp_paramhdr ph;	/* type = 0x8004 */
513 	uint16_t hmac_ids[];
514 }                   SCTP_PACKED;
515 
516 struct sctp_auth_chunk {
517 	struct sctp_chunkhdr ch;
518 	uint16_t shared_key_id;
519 	uint16_t hmac_id;
520 	uint8_t hmac[];
521 }               SCTP_PACKED;
522 
523 /* Zero checksum support draft-ietf-tsvwg-sctp-zero-checksum */
524 
525 struct sctp_zero_checksum_acceptable {
526 	struct sctp_paramhdr ph;
527 	uint32_t edmid;
528 }                             SCTP_PACKED;
529 
530 /*
531  * we pre-reserve enough room for a ECNE or CWR AND a SACK with no missing
532  * pieces. If ENCE is missing we could have a couple of blocks. This way we
533  * optimize so we MOST likely can bundle a SACK/ECN with the smallest size
534  * data chunk I will split into. We could increase throughput slightly by
535  * taking out these two but the  24-sack/8-CWR i.e. 32 bytes I pre-reserve I
536  * feel is worth it for now.
537  */
538 #ifndef SCTP_MAX_OVERHEAD
539 #ifdef INET6
540 #define SCTP_MAX_OVERHEAD (sizeof(struct sctp_data_chunk) + \
541                            sizeof(struct sctphdr) + \
542                            sizeof(struct sctp_ecne_chunk) + \
543                            sizeof(struct sctp_sack_chunk) + \
544                            sizeof(struct ip6_hdr))
545 
546 #define SCTP_MED_OVERHEAD (sizeof(struct sctp_data_chunk) + \
547                            sizeof(struct sctphdr) + \
548                            sizeof(struct ip6_hdr))
549 
550 #define SCTP_MIN_OVERHEAD (sizeof(struct ip6_hdr) + \
551                            sizeof(struct sctphdr))
552 
553 #else
554 #define SCTP_MAX_OVERHEAD (sizeof(struct sctp_data_chunk) + \
555                            sizeof(struct sctphdr) + \
556                            sizeof(struct sctp_ecne_chunk) + \
557                            sizeof(struct sctp_sack_chunk) + \
558                            sizeof(struct ip))
559 
560 #define SCTP_MED_OVERHEAD (sizeof(struct sctp_data_chunk) + \
561                            sizeof(struct sctphdr) + \
562                            sizeof(struct ip))
563 
564 #define SCTP_MIN_OVERHEAD (sizeof(struct ip) + \
565                            sizeof(struct sctphdr))
566 
567 #endif				/* INET6 */
568 #endif				/* !SCTP_MAX_OVERHEAD */
569 
570 #define SCTP_MED_V4_OVERHEAD (sizeof(struct sctp_data_chunk) + \
571                               sizeof(struct sctphdr) + \
572                               sizeof(struct ip))
573 
574 #define SCTP_MIN_V4_OVERHEAD (sizeof(struct ip) + \
575                               sizeof(struct sctphdr))
576 
577 #undef SCTP_PACKED
578 #endif				/* !__sctp_header_h__ */
579