xref: /freebsd/sys/netinet/sctp_header.h (revision 9a14aa017b21c292740c00ee098195cd46642730)
1 /*-
2  * Copyright (c) 2001-2007, by Cisco Systems, Inc. All rights reserved.
3  * Copyright (c) 2008-2011, by Randall Stewart. All rights reserved.
4  * Copyright (c) 2008-2011, by Michael Tuexen. All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions are met:
8  *
9  * a) Redistributions of source code must retain the above copyright notice,
10  *    this list of conditions and the following disclaimer.
11  *
12  * b) Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in
14  *    the documentation and/or other materials provided with the distribution.
15  *
16  * c) Neither the name of Cisco Systems, Inc. nor the names of its
17  *    contributors may be used to endorse or promote products derived
18  *    from this software without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
22  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
24  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
30  * THE POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 /* $KAME: sctp_header.h,v 1.14 2005/03/06 16:04:17 itojun Exp $	 */
34 
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 #ifndef __sctp_header_h__
39 #define __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 
58 struct sctp_ipv6addr_param {
59 	struct sctp_paramhdr ph;/* type=SCTP_IPV6_PARAM_TYPE, len=20 */
60 	uint8_t addr[SCTP_V6_ADDR_BYTES];	/* IPV6 address */
61 }                   SCTP_PACKED;
62 
63 /* Cookie Preservative */
64 struct sctp_cookie_perserve_param {
65 	struct sctp_paramhdr ph;/* type=SCTP_COOKIE_PRESERVE, len=8 */
66 	uint32_t time;		/* time in ms to extend cookie */
67 }                          SCTP_PACKED;
68 
69 #define SCTP_ARRAY_MIN_LEN 1
70 /* Host Name Address */
71 struct sctp_host_name_param {
72 	struct sctp_paramhdr ph;/* type=SCTP_HOSTNAME_ADDRESS */
73 	char name[SCTP_ARRAY_MIN_LEN];	/* host name */
74 }                    SCTP_PACKED;
75 
76 /*
77  * This is the maximum padded size of a s-a-p
78  * so paramheadr + 3 address types (6 bytes) + 2 byte pad = 12
79  */
80 #define SCTP_MAX_ADDR_PARAMS_SIZE 12
81 /* supported address type */
82 struct sctp_supported_addr_param {
83 	struct sctp_paramhdr ph;/* type=SCTP_SUPPORTED_ADDRTYPE */
84 	uint16_t addr_type[2];	/* array of supported address types */
85 }                         SCTP_PACKED;
86 
87 /* ECN parameter */
88 struct sctp_ecn_supported_param {
89 	struct sctp_paramhdr ph;/* type=SCTP_ECN_CAPABLE */
90 }                        SCTP_PACKED;
91 
92 
93 /* heartbeat info parameter */
94 struct sctp_heartbeat_info_param {
95 	struct sctp_paramhdr ph;
96 	uint32_t time_value_1;
97 	uint32_t time_value_2;
98 	uint32_t random_value1;
99 	uint32_t random_value2;
100 	uint8_t addr_family;
101 	uint8_t addr_len;
102 	/* make sure that this structure is 4 byte aligned */
103 	uint8_t padding[2];
104 	char address[SCTP_ADDRMAX];
105 }                         SCTP_PACKED;
106 
107 
108 /* draft-ietf-tsvwg-prsctp */
109 /* PR-SCTP supported parameter */
110 struct sctp_prsctp_supported_param {
111 	struct sctp_paramhdr ph;
112 }                           SCTP_PACKED;
113 
114 
115 /* draft-ietf-tsvwg-addip-sctp */
116 struct sctp_asconf_paramhdr {	/* an ASCONF "parameter" */
117 	struct sctp_paramhdr ph;/* a SCTP parameter header */
118 	uint32_t correlation_id;/* correlation id for this param */
119 }                    SCTP_PACKED;
120 
121 struct sctp_asconf_addr_param {	/* an ASCONF address parameter */
122 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
123 	struct sctp_ipv6addr_param addrp;	/* max storage size */
124 }                      SCTP_PACKED;
125 
126 
127 struct sctp_asconf_tag_param {	/* an ASCONF NAT-Vtag parameter */
128 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
129 	uint32_t local_vtag;
130 	uint32_t remote_vtag;
131 }                     SCTP_PACKED;
132 
133 
134 struct sctp_asconf_addrv4_param {	/* an ASCONF address (v4) parameter */
135 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
136 	struct sctp_ipv4addr_param addrp;	/* max storage size */
137 }                        SCTP_PACKED;
138 
139 #define SCTP_MAX_SUPPORTED_EXT 256
140 
141 struct sctp_supported_chunk_types_param {
142 	struct sctp_paramhdr ph;/* type = 0x8008  len = x */
143 	uint8_t chunk_types[];
144 }                                SCTP_PACKED;
145 
146 
147 /*
148  * Structures for DATA chunks
149  */
150 struct sctp_data {
151 	uint32_t tsn;
152 	uint16_t stream_id;
153 	uint16_t stream_sequence;
154 	uint32_t protocol_id;
155 	/* user data follows */
156 }         SCTP_PACKED;
157 
158 struct sctp_data_chunk {
159 	struct sctp_chunkhdr ch;
160 	struct sctp_data dp;
161 }               SCTP_PACKED;
162 
163 /*
164  * Structures for the control chunks
165  */
166 
167 /* Initiate (INIT)/Initiate Ack (INIT ACK) */
168 struct sctp_init {
169 	uint32_t initiate_tag;	/* initiate tag */
170 	uint32_t a_rwnd;	/* a_rwnd */
171 	uint16_t num_outbound_streams;	/* OS */
172 	uint16_t num_inbound_streams;	/* MIS */
173 	uint32_t initial_tsn;	/* I-TSN */
174 	/* optional param's follow */
175 }         SCTP_PACKED;
176 
177 #define SCTP_IDENTIFICATION_SIZE 16
178 #define SCTP_ADDRESS_SIZE 4
179 #define SCTP_RESERVE_SPACE 6
180 /* state cookie header */
181 struct sctp_state_cookie {	/* this is our definition... */
182 	uint8_t identification[SCTP_IDENTIFICATION_SIZE];	/* id of who we are */
183 	struct timeval time_entered;	/* the time I built cookie */
184 	uint32_t cookie_life;	/* life I will award this cookie */
185 	uint32_t tie_tag_my_vtag;	/* my tag in old association */
186 
187 	uint32_t tie_tag_peer_vtag;	/* peers tag in old association */
188 	uint32_t peers_vtag;	/* peers tag in INIT (for quick ref) */
189 
190 	uint32_t my_vtag;	/* my tag in INIT-ACK (for quick ref) */
191 	uint32_t address[SCTP_ADDRESS_SIZE];	/* 4 ints/128 bits */
192 	uint32_t addr_type;	/* address type */
193 	uint32_t laddress[SCTP_ADDRESS_SIZE];	/* my local from address */
194 	uint32_t laddr_type;	/* my local from address type */
195 	uint32_t scope_id;	/* v6 scope id for link-locals */
196 
197 	uint16_t peerport;	/* port address of the peer in the INIT */
198 	uint16_t myport;	/* my port address used in the INIT */
199 	uint8_t ipv4_addr_legal;/* Are V4 addr legal? */
200 	uint8_t ipv6_addr_legal;/* Are V6 addr legal? */
201 	uint8_t local_scope;	/* IPv6 local scope flag */
202 	uint8_t site_scope;	/* IPv6 site scope flag */
203 
204 	uint8_t ipv4_scope;	/* IPv4 private addr scope */
205 	uint8_t loopback_scope;	/* loopback scope information */
206 	uint8_t reserved[SCTP_RESERVE_SPACE];	/* Align to 64 bits */
207 	/*
208 	 * at the end is tacked on the INIT chunk and the INIT-ACK chunk
209 	 * (minus the cookie).
210 	 */
211 }                 SCTP_PACKED;
212 
213 
214 /* Used for NAT state error cause */
215 struct sctp_missing_nat_state {
216 	uint16_t cause;
217 	uint16_t length;
218 	uint8_t data[];
219 }                      SCTP_PACKED;
220 
221 
222 struct sctp_inv_mandatory_param {
223 	uint16_t cause;
224 	uint16_t length;
225 	uint32_t num_param;
226 	uint16_t param;
227 	/*
228 	 * We include this to 0 it since only a missing cookie will cause
229 	 * this error.
230 	 */
231 	uint16_t resv;
232 }                        SCTP_PACKED;
233 
234 struct sctp_unresolv_addr {
235 	uint16_t cause;
236 	uint16_t length;
237 	uint16_t addr_type;
238 	uint16_t reserved;	/* Only one invalid addr type */
239 }                  SCTP_PACKED;
240 
241 /* state cookie parameter */
242 struct sctp_state_cookie_param {
243 	struct sctp_paramhdr ph;
244 	struct sctp_state_cookie cookie;
245 }                       SCTP_PACKED;
246 
247 struct sctp_init_chunk {
248 	struct sctp_chunkhdr ch;
249 	struct sctp_init init;
250 }               SCTP_PACKED;
251 
252 struct sctp_init_msg {
253 	struct sctphdr sh;
254 	struct sctp_init_chunk msg;
255 }             SCTP_PACKED;
256 
257 /* ... used for both INIT and INIT ACK */
258 #define sctp_init_ack		sctp_init
259 #define sctp_init_ack_chunk	sctp_init_chunk
260 #define sctp_init_ack_msg	sctp_init_msg
261 
262 
263 /* Selective Ack (SACK) */
264 struct sctp_gap_ack_block {
265 	uint16_t start;		/* Gap Ack block start */
266 	uint16_t end;		/* Gap Ack block end */
267 }                  SCTP_PACKED;
268 
269 struct sctp_sack {
270 	uint32_t cum_tsn_ack;	/* cumulative TSN Ack */
271 	uint32_t a_rwnd;	/* updated a_rwnd of sender */
272 	uint16_t num_gap_ack_blks;	/* number of Gap Ack blocks */
273 	uint16_t num_dup_tsns;	/* number of duplicate TSNs */
274 	/* struct sctp_gap_ack_block's follow */
275 	/* uint32_t duplicate_tsn's follow */
276 }         SCTP_PACKED;
277 
278 struct sctp_sack_chunk {
279 	struct sctp_chunkhdr ch;
280 	struct sctp_sack sack;
281 }               SCTP_PACKED;
282 
283 struct sctp_nr_sack {
284 	uint32_t cum_tsn_ack;	/* cumulative TSN Ack */
285 	uint32_t a_rwnd;	/* updated a_rwnd of sender */
286 	uint16_t num_gap_ack_blks;	/* number of Gap Ack blocks */
287 	uint16_t num_nr_gap_ack_blks;	/* number of NR Gap Ack blocks */
288 	uint16_t num_dup_tsns;	/* number of duplicate TSNs */
289 	uint16_t reserved;	/* not currently used */
290 	/* struct sctp_gap_ack_block's follow */
291 	/* uint32_t duplicate_tsn's follow */
292 }            SCTP_PACKED;
293 
294 struct sctp_nr_sack_chunk {
295 	struct sctp_chunkhdr ch;
296 	struct sctp_nr_sack nr_sack;
297 }                  SCTP_PACKED;
298 
299 
300 /* Heartbeat Request (HEARTBEAT) */
301 struct sctp_heartbeat {
302 	struct sctp_heartbeat_info_param hb_info;
303 }              SCTP_PACKED;
304 
305 struct sctp_heartbeat_chunk {
306 	struct sctp_chunkhdr ch;
307 	struct sctp_heartbeat heartbeat;
308 }                    SCTP_PACKED;
309 
310 /* ... used for Heartbeat Ack (HEARTBEAT ACK) */
311 #define sctp_heartbeat_ack		sctp_heartbeat
312 #define sctp_heartbeat_ack_chunk	sctp_heartbeat_chunk
313 
314 
315 /* Abort Asssociation (ABORT) */
316 struct sctp_abort_chunk {
317 	struct sctp_chunkhdr ch;
318 	/* optional error cause may follow */
319 }                SCTP_PACKED;
320 
321 struct sctp_abort_msg {
322 	struct sctphdr sh;
323 	struct sctp_abort_chunk msg;
324 }              SCTP_PACKED;
325 
326 
327 /* Shutdown Association (SHUTDOWN) */
328 struct sctp_shutdown_chunk {
329 	struct sctp_chunkhdr ch;
330 	uint32_t cumulative_tsn_ack;
331 }                   SCTP_PACKED;
332 
333 
334 /* Shutdown Acknowledgment (SHUTDOWN ACK) */
335 struct sctp_shutdown_ack_chunk {
336 	struct sctp_chunkhdr ch;
337 }                       SCTP_PACKED;
338 
339 
340 /* Operation Error (ERROR) */
341 struct sctp_error_chunk {
342 	struct sctp_chunkhdr ch;
343 	/* optional error causes follow */
344 }                SCTP_PACKED;
345 
346 
347 /* Cookie Echo (COOKIE ECHO) */
348 struct sctp_cookie_echo_chunk {
349 	struct sctp_chunkhdr ch;
350 	struct sctp_state_cookie cookie;
351 }                      SCTP_PACKED;
352 
353 /* Cookie Acknowledgment (COOKIE ACK) */
354 struct sctp_cookie_ack_chunk {
355 	struct sctp_chunkhdr ch;
356 }                     SCTP_PACKED;
357 
358 /* Explicit Congestion Notification Echo (ECNE) */
359 struct old_sctp_ecne_chunk {
360 	struct sctp_chunkhdr ch;
361 	uint32_t tsn;
362 }                   SCTP_PACKED;
363 
364 struct sctp_ecne_chunk {
365 	struct sctp_chunkhdr ch;
366 	uint32_t tsn;
367 	uint32_t num_pkts_since_cwr;
368 }               SCTP_PACKED;
369 
370 /* Congestion Window Reduced (CWR) */
371 struct sctp_cwr_chunk {
372 	struct sctp_chunkhdr ch;
373 	uint32_t tsn;
374 }              SCTP_PACKED;
375 
376 /* Shutdown Complete (SHUTDOWN COMPLETE) */
377 struct sctp_shutdown_complete_chunk {
378 	struct sctp_chunkhdr ch;
379 }                            SCTP_PACKED;
380 
381 /* Oper error holding a stale cookie */
382 struct sctp_stale_cookie_msg {
383 	struct sctp_paramhdr ph;/* really an error cause */
384 	uint32_t time_usec;
385 }                     SCTP_PACKED;
386 
387 struct sctp_adaptation_layer_indication {
388 	struct sctp_paramhdr ph;
389 	uint32_t indication;
390 }                                SCTP_PACKED;
391 
392 struct sctp_cookie_while_shutting_down {
393 	struct sctphdr sh;
394 	struct sctp_chunkhdr ch;
395 	struct sctp_paramhdr ph;/* really an error cause */
396 }                               SCTP_PACKED;
397 
398 struct sctp_shutdown_complete_msg {
399 	struct sctphdr sh;
400 	struct sctp_shutdown_complete_chunk shut_cmp;
401 }                          SCTP_PACKED;
402 
403 /*
404  * draft-ietf-tsvwg-addip-sctp
405  */
406 /* Address/Stream Configuration Change (ASCONF) */
407 struct sctp_asconf_chunk {
408 	struct sctp_chunkhdr ch;
409 	uint32_t serial_number;
410 	/* lookup address parameter (mandatory) */
411 	/* asconf parameters follow */
412 }                 SCTP_PACKED;
413 
414 /* Address/Stream Configuration Acknowledge (ASCONF ACK) */
415 struct sctp_asconf_ack_chunk {
416 	struct sctp_chunkhdr ch;
417 	uint32_t serial_number;
418 	/* asconf parameters follow */
419 }                     SCTP_PACKED;
420 
421 /* draft-ietf-tsvwg-prsctp */
422 /* Forward Cumulative TSN (FORWARD TSN) */
423 struct sctp_forward_tsn_chunk {
424 	struct sctp_chunkhdr ch;
425 	uint32_t new_cumulative_tsn;
426 	/* stream/sequence pairs (sctp_strseq) follow */
427 }                      SCTP_PACKED;
428 
429 struct sctp_strseq {
430 	uint16_t stream;
431 	uint16_t sequence;
432 }           SCTP_PACKED;
433 
434 struct sctp_forward_tsn_msg {
435 	struct sctphdr sh;
436 	struct sctp_forward_tsn_chunk msg;
437 }                    SCTP_PACKED;
438 
439 /* should be a multiple of 4 - 1 aka 3/7/11 etc. */
440 
441 #define SCTP_NUM_DB_TO_VERIFY 31
442 
443 struct sctp_chunk_desc {
444 	uint8_t chunk_type;
445 	uint8_t data_bytes[SCTP_NUM_DB_TO_VERIFY];
446 	uint32_t tsn_ifany;
447 }               SCTP_PACKED;
448 
449 
450 struct sctp_pktdrop_chunk {
451 	struct sctp_chunkhdr ch;
452 	uint32_t bottle_bw;
453 	uint32_t current_onq;
454 	uint16_t trunc_len;
455 	uint16_t reserved;
456 	uint8_t data[];
457 }                  SCTP_PACKED;
458 
459 /**********STREAM RESET STUFF ******************/
460 
461 struct sctp_stream_reset_out_request {
462 	struct sctp_paramhdr ph;
463 	uint32_t request_seq;	/* monotonically increasing seq no */
464 	uint32_t response_seq;	/* if a response, the resp seq no */
465 	uint32_t send_reset_at_tsn;	/* last TSN I assigned outbound */
466 	uint16_t list_of_streams[];	/* if not all list of streams */
467 }                             SCTP_PACKED;
468 
469 struct sctp_stream_reset_in_request {
470 	struct sctp_paramhdr ph;
471 	uint32_t request_seq;
472 	uint16_t list_of_streams[];	/* if not all list of streams */
473 }                            SCTP_PACKED;
474 
475 
476 struct sctp_stream_reset_tsn_request {
477 	struct sctp_paramhdr ph;
478 	uint32_t request_seq;
479 }                             SCTP_PACKED;
480 
481 struct sctp_stream_reset_response {
482 	struct sctp_paramhdr ph;
483 	uint32_t response_seq;	/* if a response, the resp seq no */
484 	uint32_t result;
485 }                          SCTP_PACKED;
486 
487 struct sctp_stream_reset_response_tsn {
488 	struct sctp_paramhdr ph;
489 	uint32_t response_seq;	/* if a response, the resp seq no */
490 	uint32_t result;
491 	uint32_t senders_next_tsn;
492 	uint32_t receivers_next_tsn;
493 }                              SCTP_PACKED;
494 
495 struct sctp_stream_reset_add_strm {
496 	struct sctp_paramhdr ph;
497 	uint32_t request_seq;
498 	uint16_t number_of_streams;
499 	uint16_t reserved;
500 }                          SCTP_PACKED;
501 
502 #define SCTP_STREAM_RESET_NOTHING   0x00000000	/* Nothing for me to do */
503 #define SCTP_STREAM_RESET_PERFORMED 0x00000001	/* Did it */
504 #define SCTP_STREAM_RESET_DENIED    0x00000002	/* refused to do it */
505 #define SCTP_STREAM_RESET_ERROR_STR 0x00000003	/* bad Stream no */
506 #define SCTP_STREAM_RESET_TRY_LATER 0x00000004	/* collision, try again */
507 #define SCTP_STREAM_RESET_BAD_SEQNO 0x00000005	/* bad str-reset seq no */
508 
509 /*
510  * convience structures, note that if you are making a request for specific
511  * streams then the request will need to be an overlay structure.
512  */
513 
514 struct sctp_stream_reset_out_req {
515 	struct sctp_chunkhdr ch;
516 	struct sctp_stream_reset_out_request sr_req;
517 }                         SCTP_PACKED;
518 
519 struct sctp_stream_reset_in_req {
520 	struct sctp_chunkhdr ch;
521 	struct sctp_stream_reset_in_request sr_req;
522 }                        SCTP_PACKED;
523 
524 struct sctp_stream_reset_tsn_req {
525 	struct sctp_chunkhdr ch;
526 	struct sctp_stream_reset_tsn_request sr_req;
527 }                         SCTP_PACKED;
528 
529 struct sctp_stream_reset_resp {
530 	struct sctp_chunkhdr ch;
531 	struct sctp_stream_reset_response sr_resp;
532 }                      SCTP_PACKED;
533 
534 /* respone only valid with a TSN request */
535 struct sctp_stream_reset_resp_tsn {
536 	struct sctp_chunkhdr ch;
537 	struct sctp_stream_reset_response_tsn sr_resp;
538 }                          SCTP_PACKED;
539 
540 /****************************************************/
541 
542 /*
543  * Authenticated chunks support draft-ietf-tsvwg-sctp-auth
544  */
545 
546 /* Should we make the max be 32? */
547 #define SCTP_RANDOM_MAX_SIZE 256
548 struct sctp_auth_random {
549 	struct sctp_paramhdr ph;/* type = 0x8002 */
550 	uint8_t random_data[];
551 }                SCTP_PACKED;
552 
553 struct sctp_auth_chunk_list {
554 	struct sctp_paramhdr ph;/* type = 0x8003 */
555 	uint8_t chunk_types[];
556 }                    SCTP_PACKED;
557 
558 struct sctp_auth_hmac_algo {
559 	struct sctp_paramhdr ph;/* type = 0x8004 */
560 	uint16_t hmac_ids[];
561 }                   SCTP_PACKED;
562 
563 struct sctp_auth_chunk {
564 	struct sctp_chunkhdr ch;
565 	uint16_t shared_key_id;
566 	uint16_t hmac_id;
567 	uint8_t hmac[];
568 }               SCTP_PACKED;
569 
570 struct sctp_auth_invalid_hmac {
571 	struct sctp_paramhdr ph;
572 	uint16_t hmac_id;
573 	uint16_t padding;
574 }                      SCTP_PACKED;
575 
576 /*
577  * we pre-reserve enough room for a ECNE or CWR AND a SACK with no missing
578  * pieces. If ENCE is missing we could have a couple of blocks. This way we
579  * optimize so we MOST likely can bundle a SACK/ECN with the smallest size
580  * data chunk I will split into. We could increase throughput slightly by
581  * taking out these two but the  24-sack/8-CWR i.e. 32 bytes I pre-reserve I
582  * feel is worth it for now.
583  */
584 #ifndef SCTP_MAX_OVERHEAD
585 #ifdef INET6
586 #define SCTP_MAX_OVERHEAD (sizeof(struct sctp_data_chunk) + \
587 			   sizeof(struct sctphdr) + \
588 			   sizeof(struct sctp_ecne_chunk) + \
589 			   sizeof(struct sctp_sack_chunk) + \
590 			   sizeof(struct ip6_hdr))
591 
592 #define SCTP_MED_OVERHEAD (sizeof(struct sctp_data_chunk) + \
593 			   sizeof(struct sctphdr) + \
594 			   sizeof(struct ip6_hdr))
595 
596 
597 #define SCTP_MIN_OVERHEAD (sizeof(struct ip6_hdr) + \
598 			   sizeof(struct sctphdr))
599 
600 #else
601 #define SCTP_MAX_OVERHEAD (sizeof(struct sctp_data_chunk) + \
602 			   sizeof(struct sctphdr) + \
603 			   sizeof(struct sctp_ecne_chunk) + \
604 			   sizeof(struct sctp_sack_chunk) + \
605 			   sizeof(struct ip))
606 
607 #define SCTP_MED_OVERHEAD (sizeof(struct sctp_data_chunk) + \
608 			   sizeof(struct sctphdr) + \
609 			   sizeof(struct ip))
610 
611 
612 #define SCTP_MIN_OVERHEAD (sizeof(struct ip) + \
613 			   sizeof(struct sctphdr))
614 
615 #endif				/* INET6 */
616 #endif				/* !SCTP_MAX_OVERHEAD */
617 
618 #define SCTP_MED_V4_OVERHEAD (sizeof(struct sctp_data_chunk) + \
619 			      sizeof(struct sctphdr) + \
620 			      sizeof(struct ip))
621 
622 #define SCTP_MIN_V4_OVERHEAD (sizeof(struct ip) + \
623 			      sizeof(struct sctphdr))
624 
625 #undef SCTP_PACKED
626 #endif				/* !__sctp_header_h__ */
627