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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 #if defined(__FreeBSD__) && !defined(__Userspace__)
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD: head/sys/netinet/sctp_header.h 309682 2016-12-07 19:30:59Z tuexen $");
38 #endif
39 
40 #ifndef _NETINET_SCTP_HEADER_H_
41 #define _NETINET_SCTP_HEADER_H_
42 
43 #if defined(_WIN32) && !defined(__Userspace__)
44 #include <packon.h>
45 #endif
46 #if !defined(_WIN32)
47 #include <sys/time.h>
48 #endif
49 #include <netinet/sctp.h>
50 #include <netinet/sctp_constants.h>
51 
52 #if !defined(_WIN32)
53 #define SCTP_PACKED __attribute__((packed))
54 #else
55 #pragma pack (push, 1)
56 #define SCTP_PACKED
57 #endif
58 
59 /*
60  * Parameter structures
61  */
62 struct sctp_ipv4addr_param {
63 	struct sctp_paramhdr ph;/* type=SCTP_IPV4_PARAM_TYPE, len=8 */
64 	uint32_t addr;		/* IPV4 address */
65 } SCTP_PACKED;
66 
67 #define SCTP_V6_ADDR_BYTES 16
68 
69 
70 struct sctp_ipv6addr_param {
71 	struct sctp_paramhdr ph;/* type=SCTP_IPV6_PARAM_TYPE, len=20 */
72 	uint8_t addr[SCTP_V6_ADDR_BYTES];	/* IPV6 address */
73 } SCTP_PACKED;
74 
75 /* Cookie Preservative */
76 struct sctp_cookie_perserve_param {
77 	struct sctp_paramhdr ph;/* type=SCTP_COOKIE_PRESERVE, len=8 */
78 	uint32_t time;		/* time in ms to extend cookie */
79 } SCTP_PACKED;
80 
81 #define SCTP_ARRAY_MIN_LEN 1
82 /* Host Name Address */
83 struct sctp_host_name_param {
84 	struct sctp_paramhdr ph;/* type=SCTP_HOSTNAME_ADDRESS */
85 	char name[SCTP_ARRAY_MIN_LEN];		/* host name */
86 } SCTP_PACKED;
87 
88 /*
89  * This is the maximum padded size of a s-a-p
90  * so paramheadr + 3 address types (6 bytes) + 2 byte pad = 12
91  */
92 #define SCTP_MAX_ADDR_PARAMS_SIZE 12
93 /* supported address type */
94 struct sctp_supported_addr_param {
95 	struct sctp_paramhdr ph;/* type=SCTP_SUPPORTED_ADDRTYPE */
96 	uint16_t addr_type[2];	/* array of supported address types */
97 } SCTP_PACKED;
98 
99 /* heartbeat info parameter */
100 struct sctp_heartbeat_info_param {
101 	struct sctp_paramhdr ph;
102 	uint32_t time_value_1;
103 	uint32_t time_value_2;
104 	uint32_t random_value1;
105 	uint32_t random_value2;
106 	uint8_t addr_family;
107 	uint8_t addr_len;
108 	/* make sure that this structure is 4 byte aligned */
109 	uint8_t padding[2];
110 	char address[SCTP_ADDRMAX];
111 } SCTP_PACKED;
112 
113 
114 /* draft-ietf-tsvwg-prsctp */
115 /* PR-SCTP supported parameter */
116 struct sctp_prsctp_supported_param {
117 	struct sctp_paramhdr ph;
118 } SCTP_PACKED;
119 
120 
121 /* draft-ietf-tsvwg-addip-sctp */
122 struct sctp_asconf_paramhdr {	/* an ASCONF "parameter" */
123 	struct sctp_paramhdr ph;/* a SCTP parameter header */
124 	uint32_t correlation_id;/* correlation id for this param */
125 } SCTP_PACKED;
126 
127 struct sctp_asconf_addr_param {	/* an ASCONF address parameter */
128 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
129 	struct sctp_ipv6addr_param addrp;	/* max storage size */
130 } SCTP_PACKED;
131 
132 
133 struct sctp_asconf_tag_param {	/* an ASCONF NAT-Vtag parameter */
134 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
135         uint32_t local_vtag;
136         uint32_t remote_vtag;
137 } SCTP_PACKED;
138 
139 
140 struct sctp_asconf_addrv4_param {	/* an ASCONF address (v4) parameter */
141 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
142 	struct sctp_ipv4addr_param addrp;	/* max storage size */
143 } SCTP_PACKED;
144 
145 #define SCTP_MAX_SUPPORTED_EXT 256
146 
147 struct sctp_supported_chunk_types_param {
148 	struct sctp_paramhdr ph;/* type = 0x8008  len = x */
149 	uint8_t chunk_types[];
150 } SCTP_PACKED;
151 
152 
153 /*
154  * Structures for DATA chunks
155  */
156 struct sctp_data {
157 	uint32_t tsn;
158 	uint16_t sid;
159 	uint16_t ssn;
160 	uint32_t ppid;
161 	/* user data follows */
162 } SCTP_PACKED;
163 
164 struct sctp_data_chunk {
165 	struct sctp_chunkhdr ch;
166 	struct sctp_data dp;
167 } SCTP_PACKED;
168 
169 struct sctp_idata {
170 	uint32_t tsn;
171 	uint16_t sid;
172 	uint16_t reserved;	/* Where does the SSN go? */
173 	uint32_t mid;
174 	union {
175 		uint32_t ppid;
176 		uint32_t fsn;	/* Fragment Sequence Number */
177 	} ppid_fsn;
178 	/* user data follows */
179 } SCTP_PACKED;
180 
181 struct sctp_idata_chunk {
182 	struct sctp_chunkhdr ch;
183 	struct sctp_idata dp;
184 } SCTP_PACKED;
185 
186 /*
187  * Structures for the control chunks
188  */
189 
190 /* Initiate (INIT)/Initiate Ack (INIT ACK) */
191 struct sctp_init {
192 	uint32_t initiate_tag;	/* initiate tag */
193 	uint32_t a_rwnd;	/* a_rwnd */
194 	uint16_t num_outbound_streams;	/* OS */
195 	uint16_t num_inbound_streams;	/* MIS */
196 	uint32_t initial_tsn;	/* I-TSN */
197 	/* optional param's follow */
198 } SCTP_PACKED;
199 #define SCTP_IDENTIFICATION_SIZE 16
200 #define SCTP_ADDRESS_SIZE 4
201 #if defined(__Userspace__)
202 #define SCTP_RESERVE_SPACE 5
203 #else
204 #define SCTP_RESERVE_SPACE 6
205 #endif
206 /* state cookie header */
207 struct sctp_state_cookie {	/* this is our definition... */
208 	uint8_t identification[SCTP_IDENTIFICATION_SIZE];/* id of who we are */
209 	struct timeval time_entered;	/* the time I built cookie */
210 	uint32_t cookie_life;	/* life I will award this cookie */
211 	uint32_t tie_tag_my_vtag;	/* my tag in old association */
212 
213 	uint32_t tie_tag_peer_vtag;	/* peers tag in old association */
214 	uint32_t peers_vtag;	/* peers tag in INIT (for quick ref) */
215 
216 	uint32_t my_vtag;	/* my tag in INIT-ACK (for quick ref) */
217 	uint32_t address[SCTP_ADDRESS_SIZE];	/* 4 ints/128 bits */
218 	uint32_t addr_type;	/* address type */
219 	uint32_t laddress[SCTP_ADDRESS_SIZE];	/* my local from address */
220 	uint32_t laddr_type;	/* my local from address type */
221 	uint32_t scope_id;	/* v6 scope id for link-locals */
222 
223 	uint16_t peerport;	/* port address of the peer in the INIT */
224 	uint16_t myport;	/* my port address used in the INIT */
225 	uint8_t ipv4_addr_legal;/* Are V4 addr legal? */
226 	uint8_t ipv6_addr_legal;/* Are V6 addr legal? */
227 #if defined(__Userspace__)
228 	uint8_t conn_addr_legal;
229 #endif
230 	uint8_t local_scope;	/* IPv6 local scope flag */
231 	uint8_t site_scope;	/* IPv6 site scope flag */
232 
233 	uint8_t ipv4_scope;	/* IPv4 private addr scope */
234 	uint8_t loopback_scope;	/* loopback scope information */
235 	uint8_t reserved[SCTP_RESERVE_SPACE];    /* Align to 64 bits */
236 	/*
237 	 * at the end is tacked on the INIT chunk and the INIT-ACK chunk
238 	 * (minus the cookie).
239 	 */
240 } SCTP_PACKED;
241 
242 /* state cookie parameter */
243 struct sctp_state_cookie_param {
244 	struct sctp_paramhdr ph;
245 	struct sctp_state_cookie cookie;
246 } SCTP_PACKED;
247 
248 struct sctp_init_chunk {
249 	struct sctp_chunkhdr ch;
250 	struct sctp_init init;
251 } SCTP_PACKED;
252 
253 struct sctp_init_msg {
254 	struct sctphdr sh;
255 	struct sctp_init_chunk msg;
256 } SCTP_PACKED;
257 
258 /* ... used for both INIT and INIT ACK */
259 #define sctp_init_ack		sctp_init
260 #define sctp_init_ack_chunk	sctp_init_chunk
261 #define sctp_init_ack_msg	sctp_init_msg
262 
263 
264 /* Selective Ack (SACK) */
265 struct sctp_gap_ack_block {
266 	uint16_t start;		/* Gap Ack block start */
267 	uint16_t end;		/* Gap Ack block end */
268 } SCTP_PACKED;
269 
270 struct sctp_sack {
271 	uint32_t cum_tsn_ack;	/* cumulative TSN Ack */
272 	uint32_t a_rwnd;	/* updated a_rwnd of sender */
273 	uint16_t num_gap_ack_blks;	/* number of Gap Ack blocks */
274 	uint16_t num_dup_tsns;	/* number of duplicate TSNs */
275 	/* struct sctp_gap_ack_block's follow */
276 	/* uint32_t duplicate_tsn's follow */
277 } SCTP_PACKED;
278 
279 struct sctp_sack_chunk {
280 	struct sctp_chunkhdr ch;
281 	struct sctp_sack sack;
282 } SCTP_PACKED;
283 
284 struct sctp_nr_sack {
285 	uint32_t cum_tsn_ack;	/* cumulative TSN Ack */
286 	uint32_t a_rwnd;	/* updated a_rwnd of sender */
287 	uint16_t num_gap_ack_blks;	/* number of Gap Ack blocks */
288 	uint16_t num_nr_gap_ack_blks;	/* number of NR Gap Ack blocks */
289 	uint16_t num_dup_tsns;	/* number of duplicate TSNs */
290 	uint16_t reserved;	/* not currently used*/
291 	/* struct sctp_gap_ack_block's follow */
292 	/* uint32_t duplicate_tsn's follow */
293 } SCTP_PACKED;
294 
295 struct sctp_nr_sack_chunk {
296 	struct sctp_chunkhdr ch;
297 	struct sctp_nr_sack nr_sack;
298 } SCTP_PACKED;
299 
300 
301 /* Heartbeat Request (HEARTBEAT) */
302 struct sctp_heartbeat {
303 	struct sctp_heartbeat_info_param hb_info;
304 } SCTP_PACKED;
305 
306 struct sctp_heartbeat_chunk {
307 	struct sctp_chunkhdr ch;
308 	struct sctp_heartbeat heartbeat;
309 } SCTP_PACKED;
310 
311 /* ... used for Heartbeat Ack (HEARTBEAT ACK) */
312 #define sctp_heartbeat_ack		sctp_heartbeat
313 #define sctp_heartbeat_ack_chunk	sctp_heartbeat_chunk
314 
315 
316 /* Abort Asssociation (ABORT) */
317 struct sctp_abort_chunk {
318 	struct sctp_chunkhdr ch;
319 	/* optional error cause may follow */
320 } SCTP_PACKED;
321 
322 struct sctp_abort_msg {
323 	struct sctphdr sh;
324 	struct sctp_abort_chunk msg;
325 } SCTP_PACKED;
326 
327 
328 /* Shutdown Association (SHUTDOWN) */
329 struct sctp_shutdown_chunk {
330 	struct sctp_chunkhdr ch;
331 	uint32_t cumulative_tsn_ack;
332 } SCTP_PACKED;
333 
334 
335 /* Shutdown Acknowledgment (SHUTDOWN ACK) */
336 struct sctp_shutdown_ack_chunk {
337 	struct sctp_chunkhdr ch;
338 } SCTP_PACKED;
339 
340 
341 /* Operation Error (ERROR) */
342 struct sctp_error_chunk {
343 	struct sctp_chunkhdr ch;
344 	/* optional error causes follow */
345 } SCTP_PACKED;
346 
347 
348 /* Cookie Echo (COOKIE ECHO) */
349 struct sctp_cookie_echo_chunk {
350 	struct sctp_chunkhdr ch;
351 	struct sctp_state_cookie cookie;
352 } SCTP_PACKED;
353 
354 /* Cookie Acknowledgment (COOKIE ACK) */
355 struct sctp_cookie_ack_chunk {
356 	struct sctp_chunkhdr ch;
357 } SCTP_PACKED;
358 
359 /* Explicit Congestion Notification Echo (ECNE) */
360 struct old_sctp_ecne_chunk {
361 	struct sctp_chunkhdr ch;
362 	uint32_t tsn;
363 } SCTP_PACKED;
364 
365 struct sctp_ecne_chunk {
366 	struct sctp_chunkhdr ch;
367 	uint32_t tsn;
368 	uint32_t num_pkts_since_cwr;
369 } SCTP_PACKED;
370 
371 /* Congestion Window Reduced (CWR) */
372 struct sctp_cwr_chunk {
373 	struct sctp_chunkhdr ch;
374 	uint32_t tsn;
375 } SCTP_PACKED;
376 
377 /* Shutdown Complete (SHUTDOWN COMPLETE) */
378 struct sctp_shutdown_complete_chunk {
379 	struct sctp_chunkhdr ch;
380 } SCTP_PACKED;
381 
382 struct sctp_adaptation_layer_indication {
383 	struct sctp_paramhdr ph;
384 	uint32_t indication;
385 } SCTP_PACKED;
386 
387 /*
388  * draft-ietf-tsvwg-addip-sctp
389  */
390 /* Address/Stream Configuration Change (ASCONF) */
391 struct sctp_asconf_chunk {
392 	struct sctp_chunkhdr ch;
393 	uint32_t serial_number;
394 	/* lookup address parameter (mandatory) */
395 	/* asconf parameters follow */
396 } SCTP_PACKED;
397 
398 /* Address/Stream Configuration Acknowledge (ASCONF ACK) */
399 struct sctp_asconf_ack_chunk {
400 	struct sctp_chunkhdr ch;
401 	uint32_t serial_number;
402 	/* asconf parameters follow */
403 } SCTP_PACKED;
404 
405 /* draft-ietf-tsvwg-prsctp */
406 /* Forward Cumulative TSN (FORWARD TSN) */
407 struct sctp_forward_tsn_chunk {
408 	struct sctp_chunkhdr ch;
409 	uint32_t new_cumulative_tsn;
410 	/* stream/sequence pairs (sctp_strseq) follow */
411 } SCTP_PACKED;
412 
413 struct sctp_strseq {
414 	uint16_t sid;
415 	uint16_t ssn;
416 } SCTP_PACKED;
417 
418 struct sctp_strseq_mid {
419 	uint16_t sid;
420 	uint16_t flags;
421 	uint32_t mid;
422 };
423 
424 struct sctp_forward_tsn_msg {
425 	struct sctphdr sh;
426 	struct sctp_forward_tsn_chunk msg;
427 } SCTP_PACKED;
428 
429 /* should be a multiple of 4 - 1 aka 3/7/11 etc. */
430 
431 #define SCTP_NUM_DB_TO_VERIFY 31
432 
433 struct sctp_chunk_desc {
434 	uint8_t chunk_type;
435 	uint8_t data_bytes[SCTP_NUM_DB_TO_VERIFY];
436 	uint32_t tsn_ifany;
437 } SCTP_PACKED;
438 
439 
440 struct sctp_pktdrop_chunk {
441 	struct sctp_chunkhdr ch;
442 	uint32_t bottle_bw;
443 	uint32_t current_onq;
444 	uint16_t trunc_len;
445 	uint16_t reserved;
446 	uint8_t data[];
447 } SCTP_PACKED;
448 
449 /**********STREAM RESET STUFF ******************/
450 
451 struct sctp_stream_reset_request {
452 	struct sctp_paramhdr ph;
453 	uint32_t request_seq;
454 } SCTP_PACKED;
455 
456 struct sctp_stream_reset_out_request {
457 	struct sctp_paramhdr ph;
458 	uint32_t request_seq;	/* monotonically increasing seq no */
459 	uint32_t response_seq;	/* if a response, the resp seq no */
460 	uint32_t send_reset_at_tsn;	/* last TSN I assigned outbound */
461 	uint16_t list_of_streams[];	/* if not all list of streams */
462 } SCTP_PACKED;
463 
464 struct sctp_stream_reset_in_request {
465 	struct sctp_paramhdr ph;
466 	uint32_t request_seq;
467 	uint16_t list_of_streams[];	/* if not all list of streams */
468 } SCTP_PACKED;
469 
470 struct sctp_stream_reset_tsn_request {
471 	struct sctp_paramhdr ph;
472 	uint32_t request_seq;
473 } SCTP_PACKED;
474 
475 struct sctp_stream_reset_response {
476 	struct sctp_paramhdr ph;
477 	uint32_t response_seq;	/* if a response, the resp seq no */
478 	uint32_t result;
479 } SCTP_PACKED;
480 
481 struct sctp_stream_reset_response_tsn {
482 	struct sctp_paramhdr ph;
483 	uint32_t response_seq;	/* if a response, the resp seq no */
484 	uint32_t result;
485 	uint32_t senders_next_tsn;
486 	uint32_t receivers_next_tsn;
487 } SCTP_PACKED;
488 
489 struct sctp_stream_reset_add_strm {
490   struct sctp_paramhdr ph;
491   uint32_t request_seq;
492   uint16_t number_of_streams;
493   uint16_t reserved;
494 } SCTP_PACKED;
495 
496 #define SCTP_STREAM_RESET_RESULT_NOTHING_TO_DO   0x00000000 /* XXX: unused */
497 #define SCTP_STREAM_RESET_RESULT_PERFORMED       0x00000001
498 #define SCTP_STREAM_RESET_RESULT_DENIED          0x00000002
499 #define SCTP_STREAM_RESET_RESULT_ERR__WRONG_SSN  0x00000003 /* XXX: unused */
500 #define SCTP_STREAM_RESET_RESULT_ERR_IN_PROGRESS 0x00000004
501 #define SCTP_STREAM_RESET_RESULT_ERR_BAD_SEQNO   0x00000005
502 #define SCTP_STREAM_RESET_RESULT_IN_PROGRESS     0x00000006 /* XXX: unused */
503 
504 /*
505  * convience structures, note that if you are making a request for specific
506  * streams then the request will need to be an overlay structure.
507  */
508 
509 struct sctp_stream_reset_tsn_req {
510 	struct sctp_chunkhdr ch;
511 	struct sctp_stream_reset_tsn_request sr_req;
512 } SCTP_PACKED;
513 
514 struct sctp_stream_reset_resp {
515 	struct sctp_chunkhdr ch;
516 	struct sctp_stream_reset_response sr_resp;
517 } SCTP_PACKED;
518 
519 /* respone only valid with a TSN request */
520 struct sctp_stream_reset_resp_tsn {
521 	struct sctp_chunkhdr ch;
522 	struct sctp_stream_reset_response_tsn sr_resp;
523 } SCTP_PACKED;
524 
525 /****************************************************/
526 
527 /*
528  * Authenticated chunks support draft-ietf-tsvwg-sctp-auth
529  */
530 
531 /* Should we make the max be 32? */
532 #define SCTP_RANDOM_MAX_SIZE 256
533 struct sctp_auth_random {
534 	struct sctp_paramhdr ph;/* type = 0x8002 */
535 	uint8_t random_data[];
536 } SCTP_PACKED;
537 
538 struct sctp_auth_chunk_list {
539 	struct sctp_paramhdr ph;/* type = 0x8003 */
540 	uint8_t chunk_types[];
541 } SCTP_PACKED;
542 
543 struct sctp_auth_hmac_algo {
544 	struct sctp_paramhdr ph;/* type = 0x8004 */
545 	uint16_t hmac_ids[];
546 } SCTP_PACKED;
547 
548 struct sctp_auth_chunk {
549 	struct sctp_chunkhdr ch;
550 	uint16_t shared_key_id;
551 	uint16_t hmac_id;
552 	uint8_t hmac[];
553 } SCTP_PACKED;
554 
555 /*
556  * we pre-reserve enough room for a ECNE or CWR AND a SACK with no missing
557  * pieces. If ENCE is missing we could have a couple of blocks. This way we
558  * optimize so we MOST likely can bundle a SACK/ECN with the smallest size
559  * data chunk I will split into. We could increase throughput slightly by
560  * taking out these two but the  24-sack/8-CWR i.e. 32 bytes I pre-reserve I
561  * feel is worth it for now.
562  */
563 #ifndef SCTP_MAX_OVERHEAD
564 #ifdef INET6
565 #define SCTP_MAX_OVERHEAD (sizeof(struct sctp_data_chunk) + \
566 			   sizeof(struct sctphdr) + \
567 			   sizeof(struct sctp_ecne_chunk) + \
568 			   sizeof(struct sctp_sack_chunk) + \
569 			   sizeof(struct ip6_hdr))
570 
571 #define SCTP_MED_OVERHEAD (sizeof(struct sctp_data_chunk) + \
572 			   sizeof(struct sctphdr) + \
573 			   sizeof(struct ip6_hdr))
574 
575 
576 #define SCTP_MIN_OVERHEAD (sizeof(struct ip6_hdr) + \
577 			   sizeof(struct sctphdr))
578 
579 #else
580 #define SCTP_MAX_OVERHEAD (sizeof(struct sctp_data_chunk) + \
581 			   sizeof(struct sctphdr) + \
582 			   sizeof(struct sctp_ecne_chunk) + \
583 			   sizeof(struct sctp_sack_chunk) + \
584 			   sizeof(struct ip))
585 
586 #define SCTP_MED_OVERHEAD (sizeof(struct sctp_data_chunk) + \
587 			   sizeof(struct sctphdr) + \
588 			   sizeof(struct ip))
589 
590 
591 #define SCTP_MIN_OVERHEAD (sizeof(struct ip) + \
592 			   sizeof(struct sctphdr))
593 
594 #endif /* INET6 */
595 #endif /* !SCTP_MAX_OVERHEAD */
596 
597 #define SCTP_MED_V4_OVERHEAD (sizeof(struct sctp_data_chunk) + \
598 			      sizeof(struct sctphdr) + \
599 			      sizeof(struct ip))
600 
601 #define SCTP_MIN_V4_OVERHEAD (sizeof(struct ip) + \
602 			      sizeof(struct sctphdr))
603 
604 #if defined(_WIN32) && !defined(__Userspace__)
605 #include <packoff.h>
606 #endif
607 #if defined(_WIN32) && defined(__Userspace__)
608 #pragma pack(pop)
609 #endif
610 #undef SCTP_PACKED
611 #endif				/* !__sctp_header_h__ */
612