xref: /freebsd/sys/netinet/sctp_header.h (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
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 #ifndef _NETINET_SCTP_HEADER_H_
37 #define _NETINET_SCTP_HEADER_H_
38 
39 #include <sys/time.h>
40 #include <netinet/sctp.h>
41 #include <netinet/sctp_constants.h>
42 
43 #define SCTP_PACKED __attribute__((packed))
44 
45 /*
46  * Parameter structures
47  */
48 struct sctp_ipv4addr_param {
49 	struct sctp_paramhdr ph;	/* type=SCTP_IPV4_PARAM_TYPE, len=8 */
50 	uint32_t addr;		/* IPV4 address */
51 }                   SCTP_PACKED;
52 
53 #define SCTP_V6_ADDR_BYTES 16
54 
55 struct sctp_ipv6addr_param {
56 	struct sctp_paramhdr ph;	/* type=SCTP_IPV6_PARAM_TYPE, len=20 */
57 	uint8_t addr[SCTP_V6_ADDR_BYTES];	/* IPV6 address */
58 }                   SCTP_PACKED;
59 
60 /* Cookie Preservative */
61 struct sctp_cookie_perserve_param {
62 	struct sctp_paramhdr ph;	/* type=SCTP_COOKIE_PRESERVE, len=8 */
63 	uint32_t time;		/* time in ms to extend cookie */
64 }                          SCTP_PACKED;
65 
66 #define SCTP_ARRAY_MIN_LEN 1
67 /* Host Name Address */
68 struct sctp_host_name_param {
69 	struct sctp_paramhdr ph;	/* type=SCTP_HOSTNAME_ADDRESS */
70 	char name[SCTP_ARRAY_MIN_LEN];	/* host name */
71 }                    SCTP_PACKED;
72 
73 /*
74  * This is the maximum padded size of a s-a-p
75  * so paramheadr + 3 address types (6 bytes) + 2 byte pad = 12
76  */
77 #define SCTP_MAX_ADDR_PARAMS_SIZE 12
78 /* supported address type */
79 struct sctp_supported_addr_param {
80 	struct sctp_paramhdr ph;	/* type=SCTP_SUPPORTED_ADDRTYPE */
81 	uint16_t addr_type[2];	/* array of supported address types */
82 }                         SCTP_PACKED;
83 
84 /* heartbeat info parameter */
85 struct sctp_heartbeat_info_param {
86 	struct sctp_paramhdr ph;
87 	uint32_t time_value_1;
88 	uint32_t time_value_2;
89 	uint32_t random_value1;
90 	uint32_t random_value2;
91 	uint8_t addr_family;
92 	uint8_t addr_len;
93 	/* make sure that this structure is 4 byte aligned */
94 	uint8_t padding[2];
95 	char address[SCTP_ADDRMAX];
96 }                         SCTP_PACKED;
97 
98 /* draft-ietf-tsvwg-prsctp */
99 /* PR-SCTP supported parameter */
100 struct sctp_prsctp_supported_param {
101 	struct sctp_paramhdr ph;
102 }                           SCTP_PACKED;
103 
104 /* draft-ietf-tsvwg-addip-sctp */
105 struct sctp_asconf_paramhdr {	/* an ASCONF "parameter" */
106 	struct sctp_paramhdr ph;	/* a SCTP parameter header */
107 	uint32_t correlation_id;	/* correlation id for this param */
108 }                    SCTP_PACKED;
109 
110 struct sctp_asconf_addr_param {	/* an ASCONF address parameter */
111 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
112 	struct sctp_ipv6addr_param addrp;	/* max storage size */
113 }                      SCTP_PACKED;
114 
115 struct sctp_asconf_tag_param {	/* an ASCONF NAT-Vtag parameter */
116 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
117 	uint32_t local_vtag;
118 	uint32_t remote_vtag;
119 }                     SCTP_PACKED;
120 
121 struct sctp_asconf_addrv4_param {	/* an ASCONF address (v4) parameter */
122 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
123 	struct sctp_ipv4addr_param addrp;	/* max storage size */
124 }                        SCTP_PACKED;
125 
126 #define SCTP_MAX_SUPPORTED_EXT 256
127 
128 struct sctp_supported_chunk_types_param {
129 	struct sctp_paramhdr ph;	/* type = 0x8008  len = x */
130 	uint8_t chunk_types[];
131 }                                SCTP_PACKED;
132 
133 /*
134  * Structures for DATA chunks
135  */
136 struct sctp_data {
137 	uint32_t tsn;
138 	uint16_t sid;
139 	uint16_t ssn;
140 	uint32_t ppid;
141 	/* user data follows */
142 }         SCTP_PACKED;
143 
144 struct sctp_data_chunk {
145 	struct sctp_chunkhdr ch;
146 	struct sctp_data dp;
147 }               SCTP_PACKED;
148 
149 struct sctp_idata {
150 	uint32_t tsn;
151 	uint16_t sid;
152 	uint16_t reserved;	/* Where does the SSN go? */
153 	uint32_t mid;
154 	union {
155 		uint32_t ppid;
156 		uint32_t fsn;	/* Fragment Sequence Number */
157 	}     ppid_fsn;
158 	/* user data follows */
159 }          SCTP_PACKED;
160 
161 struct sctp_idata_chunk {
162 	struct sctp_chunkhdr ch;
163 	struct sctp_idata dp;
164 }                SCTP_PACKED;
165 
166 /*
167  * Structures for the control chunks
168  */
169 
170 /* Initiate (INIT)/Initiate Ack (INIT ACK) */
171 struct sctp_init {
172 	uint32_t initiate_tag;	/* initiate tag */
173 	uint32_t a_rwnd;	/* a_rwnd */
174 	uint16_t num_outbound_streams;	/* OS */
175 	uint16_t num_inbound_streams;	/* MIS */
176 	uint32_t initial_tsn;	/* I-TSN */
177 	/* optional param's follow */
178 }         SCTP_PACKED;
179 #define SCTP_IDENTIFICATION_SIZE 16
180 #define SCTP_ADDRESS_SIZE 4
181 #define SCTP_RESERVE_SPACE 5
182 /* state cookie header */
183 struct sctp_state_cookie {	/* this is our definition... */
184 	uint8_t identification[SCTP_IDENTIFICATION_SIZE];	/* id of who we are */
185 	struct timeval time_entered;	/* the time I built cookie */
186 	uint32_t cookie_life;	/* life I will award this cookie */
187 	uint32_t tie_tag_my_vtag;	/* my tag in old association */
188 
189 	uint32_t tie_tag_peer_vtag;	/* peers tag in old association */
190 	uint32_t peers_vtag;	/* peers tag in INIT (for quick ref) */
191 
192 	uint32_t my_vtag;	/* my tag in INIT-ACK (for quick ref) */
193 	uint32_t address[SCTP_ADDRESS_SIZE];	/* 4 ints/128 bits */
194 	uint32_t addr_type;	/* address type */
195 	uint32_t laddress[SCTP_ADDRESS_SIZE];	/* my local from address */
196 	uint32_t laddr_type;	/* my local from address type */
197 	uint32_t scope_id;	/* v6 scope id for link-locals */
198 
199 	uint16_t peerport;	/* port address of the peer in the INIT */
200 	uint16_t myport;	/* my port address used in the INIT */
201 	uint8_t ipv4_addr_legal;	/* Are V4 addr legal? */
202 	uint8_t ipv6_addr_legal;	/* Are V6 addr legal? */
203 	uint8_t local_scope;	/* IPv6 local scope flag */
204 	uint8_t site_scope;	/* IPv6 site scope flag */
205 
206 	uint8_t ipv4_scope;	/* IPv4 private addr scope */
207 	uint8_t loopback_scope;	/* loopback scope information */
208 	uint8_t rcv_edmid;	/* copy of the inp value */
209 	uint8_t reserved[SCTP_RESERVE_SPACE];	/* Align to 64 bits */
210 	/*
211 	 * at the end is tacked on the INIT chunk and the INIT-ACK chunk
212 	 * (minus the cookie).
213 	 */
214 }                 SCTP_PACKED;
215 
216 /* state cookie parameter */
217 struct sctp_state_cookie_param {
218 	struct sctp_paramhdr ph;
219 	struct sctp_state_cookie cookie;
220 }                       SCTP_PACKED;
221 
222 struct sctp_init_chunk {
223 	struct sctp_chunkhdr ch;
224 	struct sctp_init init;
225 }               SCTP_PACKED;
226 
227 struct sctp_init_msg {
228 	struct sctphdr sh;
229 	struct sctp_init_chunk msg;
230 }             SCTP_PACKED;
231 
232 /* ... used for both INIT and INIT ACK */
233 #define sctp_init_ack		sctp_init
234 #define sctp_init_ack_chunk	sctp_init_chunk
235 #define sctp_init_ack_msg	sctp_init_msg
236 
237 /* Selective Ack (SACK) */
238 struct sctp_gap_ack_block {
239 	uint16_t start;		/* Gap Ack block start */
240 	uint16_t end;		/* Gap Ack block end */
241 }                  SCTP_PACKED;
242 
243 struct sctp_sack {
244 	uint32_t cum_tsn_ack;	/* cumulative TSN Ack */
245 	uint32_t a_rwnd;	/* updated a_rwnd of sender */
246 	uint16_t num_gap_ack_blks;	/* number of Gap Ack blocks */
247 	uint16_t num_dup_tsns;	/* number of duplicate TSNs */
248 	/* struct sctp_gap_ack_block's follow */
249 	/* uint32_t duplicate_tsn's follow */
250 }         SCTP_PACKED;
251 
252 struct sctp_sack_chunk {
253 	struct sctp_chunkhdr ch;
254 	struct sctp_sack sack;
255 }               SCTP_PACKED;
256 
257 struct sctp_nr_sack {
258 	uint32_t cum_tsn_ack;	/* cumulative TSN Ack */
259 	uint32_t a_rwnd;	/* updated a_rwnd of sender */
260 	uint16_t num_gap_ack_blks;	/* number of Gap Ack blocks */
261 	uint16_t num_nr_gap_ack_blks;	/* number of NR Gap Ack blocks */
262 	uint16_t num_dup_tsns;	/* number of duplicate TSNs */
263 	uint16_t reserved;	/* not currently used */
264 	/* struct sctp_gap_ack_block's follow */
265 	/* uint32_t duplicate_tsn's follow */
266 }            SCTP_PACKED;
267 
268 struct sctp_nr_sack_chunk {
269 	struct sctp_chunkhdr ch;
270 	struct sctp_nr_sack nr_sack;
271 }                  SCTP_PACKED;
272 
273 /* Heartbeat Request (HEARTBEAT) */
274 struct sctp_heartbeat {
275 	struct sctp_heartbeat_info_param hb_info;
276 }              SCTP_PACKED;
277 
278 struct sctp_heartbeat_chunk {
279 	struct sctp_chunkhdr ch;
280 	struct sctp_heartbeat heartbeat;
281 }                    SCTP_PACKED;
282 
283 /* ... used for Heartbeat Ack (HEARTBEAT ACK) */
284 #define sctp_heartbeat_ack		sctp_heartbeat
285 #define sctp_heartbeat_ack_chunk	sctp_heartbeat_chunk
286 
287 /* Abort Asssociation (ABORT) */
288 struct sctp_abort_chunk {
289 	struct sctp_chunkhdr ch;
290 	/* optional error cause may follow */
291 }                SCTP_PACKED;
292 
293 struct sctp_abort_msg {
294 	struct sctphdr sh;
295 	struct sctp_abort_chunk msg;
296 }              SCTP_PACKED;
297 
298 /* Shutdown Association (SHUTDOWN) */
299 struct sctp_shutdown_chunk {
300 	struct sctp_chunkhdr ch;
301 	uint32_t cumulative_tsn_ack;
302 }                   SCTP_PACKED;
303 
304 /* Shutdown Acknowledgment (SHUTDOWN ACK) */
305 struct sctp_shutdown_ack_chunk {
306 	struct sctp_chunkhdr ch;
307 }                       SCTP_PACKED;
308 
309 /* Operation Error (ERROR) */
310 struct sctp_error_chunk {
311 	struct sctp_chunkhdr ch;
312 	/* optional error causes follow */
313 }                SCTP_PACKED;
314 
315 /* Cookie Echo (COOKIE ECHO) */
316 struct sctp_cookie_echo_chunk {
317 	struct sctp_chunkhdr ch;
318 	struct sctp_state_cookie cookie;
319 }                      SCTP_PACKED;
320 
321 /* Cookie Acknowledgment (COOKIE ACK) */
322 struct sctp_cookie_ack_chunk {
323 	struct sctp_chunkhdr ch;
324 }                     SCTP_PACKED;
325 
326 /* Explicit Congestion Notification Echo (ECNE) */
327 struct old_sctp_ecne_chunk {
328 	struct sctp_chunkhdr ch;
329 	uint32_t tsn;
330 }                   SCTP_PACKED;
331 
332 struct sctp_ecne_chunk {
333 	struct sctp_chunkhdr ch;
334 	uint32_t tsn;
335 	uint32_t num_pkts_since_cwr;
336 }               SCTP_PACKED;
337 
338 /* Congestion Window Reduced (CWR) */
339 struct sctp_cwr_chunk {
340 	struct sctp_chunkhdr ch;
341 	uint32_t tsn;
342 }              SCTP_PACKED;
343 
344 /* Shutdown Complete (SHUTDOWN COMPLETE) */
345 struct sctp_shutdown_complete_chunk {
346 	struct sctp_chunkhdr ch;
347 }                            SCTP_PACKED;
348 
349 struct sctp_adaptation_layer_indication {
350 	struct sctp_paramhdr ph;
351 	uint32_t indication;
352 }                                SCTP_PACKED;
353 
354 /*
355  * draft-ietf-tsvwg-addip-sctp
356  */
357 /* Address/Stream Configuration Change (ASCONF) */
358 struct sctp_asconf_chunk {
359 	struct sctp_chunkhdr ch;
360 	uint32_t serial_number;
361 	/* lookup address parameter (mandatory) */
362 	/* asconf parameters follow */
363 }                 SCTP_PACKED;
364 
365 /* Address/Stream Configuration Acknowledge (ASCONF ACK) */
366 struct sctp_asconf_ack_chunk {
367 	struct sctp_chunkhdr ch;
368 	uint32_t serial_number;
369 	/* asconf parameters follow */
370 }                     SCTP_PACKED;
371 
372 /* draft-ietf-tsvwg-prsctp */
373 /* Forward Cumulative TSN (FORWARD TSN) */
374 struct sctp_forward_tsn_chunk {
375 	struct sctp_chunkhdr ch;
376 	uint32_t new_cumulative_tsn;
377 	/* stream/sequence pairs (sctp_strseq) follow */
378 }                      SCTP_PACKED;
379 
380 struct sctp_strseq {
381 	uint16_t sid;
382 	uint16_t ssn;
383 }           SCTP_PACKED;
384 
385 struct sctp_strseq_mid {
386 	uint16_t sid;
387 	uint16_t flags;
388 	uint32_t mid;
389 };
390 
391 struct sctp_forward_tsn_msg {
392 	struct sctphdr sh;
393 	struct sctp_forward_tsn_chunk msg;
394 }                    SCTP_PACKED;
395 
396 /* should be a multiple of 4 - 1 aka 3/7/11 etc. */
397 
398 #define SCTP_NUM_DB_TO_VERIFY 31
399 
400 struct sctp_chunk_desc {
401 	uint8_t chunk_type;
402 	uint8_t data_bytes[SCTP_NUM_DB_TO_VERIFY];
403 	uint32_t tsn_ifany;
404 }               SCTP_PACKED;
405 
406 struct sctp_pktdrop_chunk {
407 	struct sctp_chunkhdr ch;
408 	uint32_t bottle_bw;
409 	uint32_t current_onq;
410 	uint16_t trunc_len;
411 	uint16_t reserved;
412 	uint8_t data[];
413 }                  SCTP_PACKED;
414 
415 /**********STREAM RESET STUFF ******************/
416 
417 struct sctp_stream_reset_request {
418 	struct sctp_paramhdr ph;
419 	uint32_t request_seq;
420 }                         SCTP_PACKED;
421 
422 struct sctp_stream_reset_out_request {
423 	struct sctp_paramhdr ph;
424 	uint32_t request_seq;	/* monotonically increasing seq no */
425 	uint32_t response_seq;	/* if a response, the resp seq no */
426 	uint32_t send_reset_at_tsn;	/* last TSN I assigned outbound */
427 	uint16_t list_of_streams[];	/* if not all list of streams */
428 }                             SCTP_PACKED;
429 
430 struct sctp_stream_reset_in_request {
431 	struct sctp_paramhdr ph;
432 	uint32_t request_seq;
433 	uint16_t list_of_streams[];	/* if not all list of streams */
434 }                            SCTP_PACKED;
435 
436 struct sctp_stream_reset_tsn_request {
437 	struct sctp_paramhdr ph;
438 	uint32_t request_seq;
439 }                             SCTP_PACKED;
440 
441 struct sctp_stream_reset_response {
442 	struct sctp_paramhdr ph;
443 	uint32_t response_seq;	/* if a response, the resp seq no */
444 	uint32_t result;
445 }                          SCTP_PACKED;
446 
447 struct sctp_stream_reset_response_tsn {
448 	struct sctp_paramhdr ph;
449 	uint32_t response_seq;	/* if a response, the resp seq no */
450 	uint32_t result;
451 	uint32_t senders_next_tsn;
452 	uint32_t receivers_next_tsn;
453 }                              SCTP_PACKED;
454 
455 struct sctp_stream_reset_add_strm {
456 	struct sctp_paramhdr ph;
457 	uint32_t request_seq;
458 	uint16_t number_of_streams;
459 	uint16_t reserved;
460 }                          SCTP_PACKED;
461 
462 #define SCTP_STREAM_RESET_RESULT_NOTHING_TO_DO   0x00000000	/* XXX: unused */
463 #define SCTP_STREAM_RESET_RESULT_PERFORMED       0x00000001
464 #define SCTP_STREAM_RESET_RESULT_DENIED          0x00000002
465 #define SCTP_STREAM_RESET_RESULT_ERR__WRONG_SSN  0x00000003	/* XXX: unused */
466 #define SCTP_STREAM_RESET_RESULT_ERR_IN_PROGRESS 0x00000004
467 #define SCTP_STREAM_RESET_RESULT_ERR_BAD_SEQNO   0x00000005
468 #define SCTP_STREAM_RESET_RESULT_IN_PROGRESS     0x00000006	/* XXX: unused */
469 
470 /*
471  * convience structures, note that if you are making a request for specific
472  * streams then the request will need to be an overlay structure.
473  */
474 
475 struct sctp_stream_reset_tsn_req {
476 	struct sctp_chunkhdr ch;
477 	struct sctp_stream_reset_tsn_request sr_req;
478 }                         SCTP_PACKED;
479 
480 struct sctp_stream_reset_resp {
481 	struct sctp_chunkhdr ch;
482 	struct sctp_stream_reset_response sr_resp;
483 }                      SCTP_PACKED;
484 
485 /* respone only valid with a TSN request */
486 struct sctp_stream_reset_resp_tsn {
487 	struct sctp_chunkhdr ch;
488 	struct sctp_stream_reset_response_tsn sr_resp;
489 }                          SCTP_PACKED;
490 
491 /****************************************************/
492 
493 /*
494  * Authenticated chunks support draft-ietf-tsvwg-sctp-auth
495  */
496 
497 /* Should we make the max be 32? */
498 #define SCTP_RANDOM_MAX_SIZE 256
499 struct sctp_auth_random {
500 	struct sctp_paramhdr ph;	/* type = 0x8002 */
501 	uint8_t random_data[];
502 }                SCTP_PACKED;
503 
504 struct sctp_auth_chunk_list {
505 	struct sctp_paramhdr ph;	/* type = 0x8003 */
506 	uint8_t chunk_types[];
507 }                    SCTP_PACKED;
508 
509 struct sctp_auth_hmac_algo {
510 	struct sctp_paramhdr ph;	/* type = 0x8004 */
511 	uint16_t hmac_ids[];
512 }                   SCTP_PACKED;
513 
514 struct sctp_auth_chunk {
515 	struct sctp_chunkhdr ch;
516 	uint16_t shared_key_id;
517 	uint16_t hmac_id;
518 	uint8_t hmac[];
519 }               SCTP_PACKED;
520 
521 /* Zero checksum support draft-ietf-tsvwg-sctp-zero-checksum */
522 
523 struct sctp_zero_checksum_acceptable {
524 	struct sctp_paramhdr ph;
525 	uint32_t edmid;
526 }                             SCTP_PACKED;
527 
528 /*
529  * we pre-reserve enough room for a ECNE or CWR AND a SACK with no missing
530  * pieces. If ENCE is missing we could have a couple of blocks. This way we
531  * optimize so we MOST likely can bundle a SACK/ECN with the smallest size
532  * data chunk I will split into. We could increase throughput slightly by
533  * taking out these two but the  24-sack/8-CWR i.e. 32 bytes I pre-reserve I
534  * feel is worth it for now.
535  */
536 #ifndef SCTP_MAX_OVERHEAD
537 #ifdef INET6
538 #define SCTP_MAX_OVERHEAD (sizeof(struct sctp_data_chunk) + \
539                            sizeof(struct sctphdr) + \
540                            sizeof(struct sctp_ecne_chunk) + \
541                            sizeof(struct sctp_sack_chunk) + \
542                            sizeof(struct ip6_hdr))
543 
544 #define SCTP_MED_OVERHEAD (sizeof(struct sctp_data_chunk) + \
545                            sizeof(struct sctphdr) + \
546                            sizeof(struct ip6_hdr))
547 
548 #define SCTP_MIN_OVERHEAD (sizeof(struct ip6_hdr) + \
549                            sizeof(struct sctphdr))
550 
551 #else
552 #define SCTP_MAX_OVERHEAD (sizeof(struct sctp_data_chunk) + \
553                            sizeof(struct sctphdr) + \
554                            sizeof(struct sctp_ecne_chunk) + \
555                            sizeof(struct sctp_sack_chunk) + \
556                            sizeof(struct ip))
557 
558 #define SCTP_MED_OVERHEAD (sizeof(struct sctp_data_chunk) + \
559                            sizeof(struct sctphdr) + \
560                            sizeof(struct ip))
561 
562 #define SCTP_MIN_OVERHEAD (sizeof(struct ip) + \
563                            sizeof(struct sctphdr))
564 
565 #endif				/* INET6 */
566 #endif				/* !SCTP_MAX_OVERHEAD */
567 
568 #define SCTP_MED_V4_OVERHEAD (sizeof(struct sctp_data_chunk) + \
569                               sizeof(struct sctphdr) + \
570                               sizeof(struct ip))
571 
572 #define SCTP_MIN_V4_OVERHEAD (sizeof(struct ip) + \
573                               sizeof(struct sctphdr))
574 
575 #undef SCTP_PACKED
576 #endif				/* !__sctp_header_h__ */
577