xref: /freebsd/sys/netinet/sctp_header.h (revision b67716dd58b93f373523cf35373c56fcfad44b12)
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 #ifndef _NETINET_SCTP_HEADER_H_
36 #define _NETINET_SCTP_HEADER_H_
37 
38 #include <sys/time.h>
39 #include <netinet/sctp.h>
40 #include <netinet/sctp_constants.h>
41 
42 #define SCTP_PACKED __attribute__((packed))
43 
44 /*
45  * Parameter structures
46  */
47 struct sctp_ipv4addr_param {
48 	struct sctp_paramhdr ph;	/* type=SCTP_IPV4_PARAM_TYPE, len=8 */
49 	uint32_t addr;		/* IPV4 address */
50 }                   SCTP_PACKED;
51 
52 #define SCTP_V6_ADDR_BYTES 16
53 
54 struct sctp_ipv6addr_param {
55 	struct sctp_paramhdr ph;	/* type=SCTP_IPV6_PARAM_TYPE, len=20 */
56 	uint8_t addr[SCTP_V6_ADDR_BYTES];	/* IPV6 address */
57 }                   SCTP_PACKED;
58 
59 /* Cookie Preservative */
60 struct sctp_cookie_perserve_param {
61 	struct sctp_paramhdr ph;	/* type=SCTP_COOKIE_PRESERVE, len=8 */
62 	uint32_t time;		/* time in ms to extend cookie */
63 }                          SCTP_PACKED;
64 
65 #define SCTP_ARRAY_MIN_LEN 1
66 /* Host Name Address */
67 struct sctp_host_name_param {
68 	struct sctp_paramhdr ph;	/* type=SCTP_HOSTNAME_ADDRESS */
69 	char name[SCTP_ARRAY_MIN_LEN];	/* host name */
70 }                    SCTP_PACKED;
71 
72 /*
73  * This is the maximum padded size of a s-a-p
74  * so paramheadr + 3 address types (6 bytes) + 2 byte pad = 12
75  */
76 #define SCTP_MAX_ADDR_PARAMS_SIZE 12
77 /* supported address type */
78 struct sctp_supported_addr_param {
79 	struct sctp_paramhdr ph;	/* type=SCTP_SUPPORTED_ADDRTYPE */
80 	uint16_t addr_type[2];	/* array of supported address types */
81 }                         SCTP_PACKED;
82 
83 /* heartbeat info parameter */
84 struct sctp_heartbeat_info_param {
85 	struct sctp_paramhdr ph;
86 	time_t time_value_1;
87 	uint32_t time_value_2;
88 	uint32_t random_value1;
89 	uint32_t random_value2;
90 	uint8_t addr_family;
91 	uint8_t addr_len;
92 	/* make sure that this structure is 4 byte aligned */
93 	uint8_t padding[2];
94 	char address[SCTP_ADDRMAX];
95 }                         SCTP_PACKED;
96 
97 /* draft-ietf-tsvwg-prsctp */
98 /* PR-SCTP supported parameter */
99 struct sctp_prsctp_supported_param {
100 	struct sctp_paramhdr ph;
101 }                           SCTP_PACKED;
102 
103 /* draft-ietf-tsvwg-addip-sctp */
104 struct sctp_asconf_paramhdr {	/* an ASCONF "parameter" */
105 	struct sctp_paramhdr ph;	/* a SCTP parameter header */
106 	uint32_t correlation_id;	/* correlation id for this param */
107 }                    SCTP_PACKED;
108 
109 struct sctp_asconf_addr_param {	/* an ASCONF address parameter */
110 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
111 	struct sctp_ipv6addr_param addrp;	/* max storage size */
112 }                      SCTP_PACKED;
113 
114 struct sctp_asconf_tag_param {	/* an ASCONF NAT-Vtag parameter */
115 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
116 	uint32_t local_vtag;
117 	uint32_t remote_vtag;
118 }                     SCTP_PACKED;
119 
120 struct sctp_asconf_addrv4_param {	/* an ASCONF address (v4) parameter */
121 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
122 	struct sctp_ipv4addr_param addrp;	/* max storage size */
123 }                        SCTP_PACKED;
124 
125 #define SCTP_MAX_SUPPORTED_EXT 256
126 
127 struct sctp_supported_chunk_types_param {
128 	struct sctp_paramhdr ph;	/* type = 0x8008  len = x */
129 	uint8_t chunk_types[];
130 }                                SCTP_PACKED;
131 
132 /*
133  * Structures for DATA chunks
134  */
135 struct sctp_data {
136 	uint32_t tsn;
137 	uint16_t sid;
138 	uint16_t ssn;
139 	uint32_t ppid;
140 	/* user data follows */
141 }         SCTP_PACKED;
142 
143 struct sctp_data_chunk {
144 	struct sctp_chunkhdr ch;
145 	struct sctp_data dp;
146 }               SCTP_PACKED;
147 
148 struct sctp_idata {
149 	uint32_t tsn;
150 	uint16_t sid;
151 	uint16_t reserved;	/* Where does the SSN go? */
152 	uint32_t mid;
153 	union {
154 		uint32_t ppid;
155 		uint32_t fsn;	/* Fragment Sequence Number */
156 	}     ppid_fsn;
157 	/* user data follows */
158 }          SCTP_PACKED;
159 
160 struct sctp_idata_chunk {
161 	struct sctp_chunkhdr ch;
162 	struct sctp_idata dp;
163 }                SCTP_PACKED;
164 
165 /*
166  * Structures for the control chunks
167  */
168 
169 /* Initiate (INIT)/Initiate Ack (INIT ACK) */
170 struct sctp_init {
171 	uint32_t initiate_tag;	/* initiate tag */
172 	uint32_t a_rwnd;	/* a_rwnd */
173 	uint16_t num_outbound_streams;	/* OS */
174 	uint16_t num_inbound_streams;	/* MIS */
175 	uint32_t initial_tsn;	/* I-TSN */
176 	/* optional param's follow */
177 }         SCTP_PACKED;
178 #define SCTP_IDENTIFICATION_SIZE 16
179 #define SCTP_ADDRESS_SIZE 4
180 #define SCTP_RESERVE_SPACE 5
181 /* state cookie header */
182 struct sctp_state_cookie {	/* this is our definition... */
183 	uint8_t identification[SCTP_IDENTIFICATION_SIZE];	/* id of who we are */
184 	struct timeval time_entered;	/* the time I built cookie */
185 	uint32_t cookie_life;	/* life I will award this cookie */
186 	uint32_t tie_tag_my_vtag;	/* my tag in old association */
187 
188 	uint32_t tie_tag_peer_vtag;	/* peers tag in old association */
189 	uint32_t peers_vtag;	/* peers tag in INIT (for quick ref) */
190 
191 	uint32_t my_vtag;	/* my tag in INIT-ACK (for quick ref) */
192 	uint32_t address[SCTP_ADDRESS_SIZE];	/* 4 ints/128 bits */
193 	uint32_t addr_type;	/* address type */
194 	uint32_t laddress[SCTP_ADDRESS_SIZE];	/* my local from address */
195 	uint32_t laddr_type;	/* my local from address type */
196 	uint32_t scope_id;	/* v6 scope id for link-locals */
197 
198 	uint16_t peerport;	/* port address of the peer in the INIT */
199 	uint16_t myport;	/* my port address used in the INIT */
200 	uint8_t ipv4_addr_legal;	/* Are V4 addr legal? */
201 	uint8_t ipv6_addr_legal;	/* Are V6 addr legal? */
202 	uint8_t local_scope;	/* IPv6 local scope flag */
203 	uint8_t site_scope;	/* IPv6 site scope flag */
204 
205 	uint8_t ipv4_scope;	/* IPv4 private addr scope */
206 	uint8_t loopback_scope;	/* loopback scope information */
207 	uint8_t rcv_edmid;	/* copy of the inp value */
208 	uint8_t reserved[SCTP_RESERVE_SPACE];	/* Align to 64 bits */
209 	/*
210 	 * at the end is tacked on the INIT chunk and the INIT-ACK chunk
211 	 * (minus the cookie).
212 	 */
213 }                 SCTP_PACKED;
214 
215 /* state cookie parameter */
216 struct sctp_state_cookie_param {
217 	struct sctp_paramhdr ph;
218 	struct sctp_state_cookie cookie;
219 }                       SCTP_PACKED;
220 
221 struct sctp_init_chunk {
222 	struct sctp_chunkhdr ch;
223 	struct sctp_init init;
224 }               SCTP_PACKED;
225 
226 struct sctp_init_msg {
227 	struct sctphdr sh;
228 	struct sctp_init_chunk msg;
229 }             SCTP_PACKED;
230 
231 /* ... used for both INIT and INIT ACK */
232 #define sctp_init_ack		sctp_init
233 #define sctp_init_ack_chunk	sctp_init_chunk
234 #define sctp_init_ack_msg	sctp_init_msg
235 
236 /* Selective Ack (SACK) */
237 struct sctp_gap_ack_block {
238 	uint16_t start;		/* Gap Ack block start */
239 	uint16_t end;		/* Gap Ack block end */
240 }                  SCTP_PACKED;
241 
242 struct sctp_sack {
243 	uint32_t cum_tsn_ack;	/* cumulative TSN Ack */
244 	uint32_t a_rwnd;	/* updated a_rwnd of sender */
245 	uint16_t num_gap_ack_blks;	/* number of Gap Ack blocks */
246 	uint16_t num_dup_tsns;	/* number of duplicate TSNs */
247 	/* struct sctp_gap_ack_block's follow */
248 	/* uint32_t duplicate_tsn's follow */
249 }         SCTP_PACKED;
250 
251 struct sctp_sack_chunk {
252 	struct sctp_chunkhdr ch;
253 	struct sctp_sack sack;
254 }               SCTP_PACKED;
255 
256 struct sctp_nr_sack {
257 	uint32_t cum_tsn_ack;	/* cumulative TSN Ack */
258 	uint32_t a_rwnd;	/* updated a_rwnd of sender */
259 	uint16_t num_gap_ack_blks;	/* number of Gap Ack blocks */
260 	uint16_t num_nr_gap_ack_blks;	/* number of NR Gap Ack blocks */
261 	uint16_t num_dup_tsns;	/* number of duplicate TSNs */
262 	uint16_t reserved;	/* not currently used */
263 	/* struct sctp_gap_ack_block's follow */
264 	/* uint32_t duplicate_tsn's follow */
265 }            SCTP_PACKED;
266 
267 struct sctp_nr_sack_chunk {
268 	struct sctp_chunkhdr ch;
269 	struct sctp_nr_sack nr_sack;
270 }                  SCTP_PACKED;
271 
272 /* Heartbeat Request (HEARTBEAT) */
273 struct sctp_heartbeat {
274 	struct sctp_heartbeat_info_param hb_info;
275 }              SCTP_PACKED;
276 
277 struct sctp_heartbeat_chunk {
278 	struct sctp_chunkhdr ch;
279 	struct sctp_heartbeat heartbeat;
280 }                    SCTP_PACKED;
281 
282 /* ... used for Heartbeat Ack (HEARTBEAT ACK) */
283 #define sctp_heartbeat_ack		sctp_heartbeat
284 #define sctp_heartbeat_ack_chunk	sctp_heartbeat_chunk
285 
286 /* Abort Asssociation (ABORT) */
287 struct sctp_abort_chunk {
288 	struct sctp_chunkhdr ch;
289 	/* optional error cause may follow */
290 }                SCTP_PACKED;
291 
292 struct sctp_abort_msg {
293 	struct sctphdr sh;
294 	struct sctp_abort_chunk msg;
295 }              SCTP_PACKED;
296 
297 /* Shutdown Association (SHUTDOWN) */
298 struct sctp_shutdown_chunk {
299 	struct sctp_chunkhdr ch;
300 	uint32_t cumulative_tsn_ack;
301 }                   SCTP_PACKED;
302 
303 /* Shutdown Acknowledgment (SHUTDOWN ACK) */
304 struct sctp_shutdown_ack_chunk {
305 	struct sctp_chunkhdr ch;
306 }                       SCTP_PACKED;
307 
308 /* Operation Error (ERROR) */
309 struct sctp_error_chunk {
310 	struct sctp_chunkhdr ch;
311 	/* optional error causes follow */
312 }                SCTP_PACKED;
313 
314 /* Cookie Echo (COOKIE ECHO) */
315 struct sctp_cookie_echo_chunk {
316 	struct sctp_chunkhdr ch;
317 	struct sctp_state_cookie cookie;
318 }                      SCTP_PACKED;
319 
320 /* Cookie Acknowledgment (COOKIE ACK) */
321 struct sctp_cookie_ack_chunk {
322 	struct sctp_chunkhdr ch;
323 }                     SCTP_PACKED;
324 
325 /* Explicit Congestion Notification Echo (ECNE) */
326 struct old_sctp_ecne_chunk {
327 	struct sctp_chunkhdr ch;
328 	uint32_t tsn;
329 }                   SCTP_PACKED;
330 
331 struct sctp_ecne_chunk {
332 	struct sctp_chunkhdr ch;
333 	uint32_t tsn;
334 	uint32_t num_pkts_since_cwr;
335 }               SCTP_PACKED;
336 
337 /* Congestion Window Reduced (CWR) */
338 struct sctp_cwr_chunk {
339 	struct sctp_chunkhdr ch;
340 	uint32_t tsn;
341 }              SCTP_PACKED;
342 
343 /* Shutdown Complete (SHUTDOWN COMPLETE) */
344 struct sctp_shutdown_complete_chunk {
345 	struct sctp_chunkhdr ch;
346 }                            SCTP_PACKED;
347 
348 struct sctp_adaptation_layer_indication {
349 	struct sctp_paramhdr ph;
350 	uint32_t indication;
351 }                                SCTP_PACKED;
352 
353 /*
354  * draft-ietf-tsvwg-addip-sctp
355  */
356 /* Address/Stream Configuration Change (ASCONF) */
357 struct sctp_asconf_chunk {
358 	struct sctp_chunkhdr ch;
359 	uint32_t serial_number;
360 	/* lookup address parameter (mandatory) */
361 	/* asconf parameters follow */
362 }                 SCTP_PACKED;
363 
364 /* Address/Stream Configuration Acknowledge (ASCONF ACK) */
365 struct sctp_asconf_ack_chunk {
366 	struct sctp_chunkhdr ch;
367 	uint32_t serial_number;
368 	/* asconf parameters follow */
369 }                     SCTP_PACKED;
370 
371 /* draft-ietf-tsvwg-prsctp */
372 /* Forward Cumulative TSN (FORWARD TSN) */
373 struct sctp_forward_tsn_chunk {
374 	struct sctp_chunkhdr ch;
375 	uint32_t new_cumulative_tsn;
376 	/* stream/sequence pairs (sctp_strseq) follow */
377 }                      SCTP_PACKED;
378 
379 struct sctp_strseq {
380 	uint16_t sid;
381 	uint16_t ssn;
382 }           SCTP_PACKED;
383 
384 struct sctp_strseq_mid {
385 	uint16_t sid;
386 	uint16_t flags;
387 	uint32_t mid;
388 };
389 
390 struct sctp_forward_tsn_msg {
391 	struct sctphdr sh;
392 	struct sctp_forward_tsn_chunk msg;
393 }                    SCTP_PACKED;
394 
395 /* should be a multiple of 4 - 1 aka 3/7/11 etc. */
396 
397 #define SCTP_NUM_DB_TO_VERIFY 31
398 
399 struct sctp_chunk_desc {
400 	uint8_t chunk_type;
401 	uint8_t data_bytes[SCTP_NUM_DB_TO_VERIFY];
402 	uint32_t tsn_ifany;
403 }               SCTP_PACKED;
404 
405 struct sctp_pktdrop_chunk {
406 	struct sctp_chunkhdr ch;
407 	uint32_t bottle_bw;
408 	uint32_t current_onq;
409 	uint16_t trunc_len;
410 	uint16_t reserved;
411 	uint8_t data[];
412 }                  SCTP_PACKED;
413 
414 /**********STREAM RESET STUFF ******************/
415 
416 struct sctp_stream_reset_request {
417 	struct sctp_paramhdr ph;
418 	uint32_t request_seq;
419 }                         SCTP_PACKED;
420 
421 struct sctp_stream_reset_out_request {
422 	struct sctp_paramhdr ph;
423 	uint32_t request_seq;	/* monotonically increasing seq no */
424 	uint32_t response_seq;	/* if a response, the resp seq no */
425 	uint32_t send_reset_at_tsn;	/* last TSN I assigned outbound */
426 	uint16_t list_of_streams[];	/* if not all list of streams */
427 }                             SCTP_PACKED;
428 
429 struct sctp_stream_reset_in_request {
430 	struct sctp_paramhdr ph;
431 	uint32_t request_seq;
432 	uint16_t list_of_streams[];	/* if not all list of streams */
433 }                            SCTP_PACKED;
434 
435 struct sctp_stream_reset_tsn_request {
436 	struct sctp_paramhdr ph;
437 	uint32_t request_seq;
438 }                             SCTP_PACKED;
439 
440 struct sctp_stream_reset_response {
441 	struct sctp_paramhdr ph;
442 	uint32_t response_seq;	/* if a response, the resp seq no */
443 	uint32_t result;
444 }                          SCTP_PACKED;
445 
446 struct sctp_stream_reset_response_tsn {
447 	struct sctp_paramhdr ph;
448 	uint32_t response_seq;	/* if a response, the resp seq no */
449 	uint32_t result;
450 	uint32_t senders_next_tsn;
451 	uint32_t receivers_next_tsn;
452 }                              SCTP_PACKED;
453 
454 struct sctp_stream_reset_add_strm {
455 	struct sctp_paramhdr ph;
456 	uint32_t request_seq;
457 	uint16_t number_of_streams;
458 	uint16_t reserved;
459 }                          SCTP_PACKED;
460 
461 #define SCTP_STREAM_RESET_RESULT_NOTHING_TO_DO   0x00000000	/* XXX: unused */
462 #define SCTP_STREAM_RESET_RESULT_PERFORMED       0x00000001
463 #define SCTP_STREAM_RESET_RESULT_DENIED          0x00000002
464 #define SCTP_STREAM_RESET_RESULT_ERR__WRONG_SSN  0x00000003	/* XXX: unused */
465 #define SCTP_STREAM_RESET_RESULT_ERR_IN_PROGRESS 0x00000004
466 #define SCTP_STREAM_RESET_RESULT_ERR_BAD_SEQNO   0x00000005
467 #define SCTP_STREAM_RESET_RESULT_IN_PROGRESS     0x00000006	/* XXX: unused */
468 
469 /*
470  * convience structures, note that if you are making a request for specific
471  * streams then the request will need to be an overlay structure.
472  */
473 
474 struct sctp_stream_reset_tsn_req {
475 	struct sctp_chunkhdr ch;
476 	struct sctp_stream_reset_tsn_request sr_req;
477 }                         SCTP_PACKED;
478 
479 struct sctp_stream_reset_resp {
480 	struct sctp_chunkhdr ch;
481 	struct sctp_stream_reset_response sr_resp;
482 }                      SCTP_PACKED;
483 
484 /* respone only valid with a TSN request */
485 struct sctp_stream_reset_resp_tsn {
486 	struct sctp_chunkhdr ch;
487 	struct sctp_stream_reset_response_tsn sr_resp;
488 }                          SCTP_PACKED;
489 
490 /****************************************************/
491 
492 /*
493  * Authenticated chunks support draft-ietf-tsvwg-sctp-auth
494  */
495 
496 /* Should we make the max be 32? */
497 #define SCTP_RANDOM_MAX_SIZE 256
498 struct sctp_auth_random {
499 	struct sctp_paramhdr ph;	/* type = 0x8002 */
500 	uint8_t random_data[];
501 }                SCTP_PACKED;
502 
503 struct sctp_auth_chunk_list {
504 	struct sctp_paramhdr ph;	/* type = 0x8003 */
505 	uint8_t chunk_types[];
506 }                    SCTP_PACKED;
507 
508 struct sctp_auth_hmac_algo {
509 	struct sctp_paramhdr ph;	/* type = 0x8004 */
510 	uint16_t hmac_ids[];
511 }                   SCTP_PACKED;
512 
513 struct sctp_auth_chunk {
514 	struct sctp_chunkhdr ch;
515 	uint16_t shared_key_id;
516 	uint16_t hmac_id;
517 	uint8_t hmac[];
518 }               SCTP_PACKED;
519 
520 /* Zero checksum support draft-ietf-tsvwg-sctp-zero-checksum */
521 
522 struct sctp_zero_checksum_acceptable {
523 	struct sctp_paramhdr ph;
524 	uint32_t edmid;
525 }                             SCTP_PACKED;
526 
527 /*
528  * we pre-reserve enough room for a ECNE or CWR AND a SACK with no missing
529  * pieces. If ENCE is missing we could have a couple of blocks. This way we
530  * optimize so we MOST likely can bundle a SACK/ECN with the smallest size
531  * data chunk I will split into. We could increase throughput slightly by
532  * taking out these two but the  24-sack/8-CWR i.e. 32 bytes I pre-reserve I
533  * feel is worth it for now.
534  */
535 #ifndef SCTP_MAX_OVERHEAD
536 #ifdef INET6
537 #define SCTP_MAX_OVERHEAD (sizeof(struct sctp_data_chunk) + \
538                            sizeof(struct sctphdr) + \
539                            sizeof(struct sctp_ecne_chunk) + \
540                            sizeof(struct sctp_sack_chunk) + \
541                            sizeof(struct ip6_hdr))
542 
543 #define SCTP_MED_OVERHEAD (sizeof(struct sctp_data_chunk) + \
544                            sizeof(struct sctphdr) + \
545                            sizeof(struct ip6_hdr))
546 
547 #define SCTP_MIN_OVERHEAD (sizeof(struct ip6_hdr) + \
548                            sizeof(struct sctphdr))
549 
550 #else
551 #define SCTP_MAX_OVERHEAD (sizeof(struct sctp_data_chunk) + \
552                            sizeof(struct sctphdr) + \
553                            sizeof(struct sctp_ecne_chunk) + \
554                            sizeof(struct sctp_sack_chunk) + \
555                            sizeof(struct ip))
556 
557 #define SCTP_MED_OVERHEAD (sizeof(struct sctp_data_chunk) + \
558                            sizeof(struct sctphdr) + \
559                            sizeof(struct ip))
560 
561 #define SCTP_MIN_OVERHEAD (sizeof(struct ip) + \
562                            sizeof(struct sctphdr))
563 
564 #endif				/* INET6 */
565 #endif				/* !SCTP_MAX_OVERHEAD */
566 
567 #define SCTP_MED_V4_OVERHEAD (sizeof(struct sctp_data_chunk) + \
568                               sizeof(struct sctphdr) + \
569                               sizeof(struct ip))
570 
571 #define SCTP_MIN_V4_OVERHEAD (sizeof(struct ip) + \
572                               sizeof(struct sctphdr))
573 
574 #undef SCTP_PACKED
575 #endif				/* !__sctp_header_h__ */
576