xref: /freebsd/sys/netinet/sctp_header.h (revision 39beb93c)
1 /*-
2  * Copyright (c) 2001-2007, by Cisco Systems, Inc. All rights reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions are met:
6  *
7  * a) Redistributions of source code must retain the above copyright notice,
8  *   this list of conditions and the following disclaimer.
9  *
10  * b) Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in
12  *   the documentation and/or other materials provided with the distribution.
13  *
14  * c) Neither the name of Cisco Systems, Inc. nor the names of its
15  *    contributors may be used to endorse or promote products derived
16  *    from this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
20  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
22  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
28  * THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 /* $KAME: sctp_header.h,v 1.14 2005/03/06 16:04:17 itojun Exp $	 */
32 
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35 
36 #ifndef __sctp_header_h__
37 #define __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 
56 struct sctp_ipv6addr_param {
57 	struct sctp_paramhdr ph;/* type=SCTP_IPV6_PARAM_TYPE, len=20 */
58 	uint8_t addr[SCTP_V6_ADDR_BYTES];	/* IPV6 address */
59 }                   SCTP_PACKED;
60 
61 /* Cookie Preservative */
62 struct sctp_cookie_perserve_param {
63 	struct sctp_paramhdr ph;/* type=SCTP_COOKIE_PRESERVE, len=8 */
64 	uint32_t time;		/* time in ms to extend cookie */
65 };
66 
67 #define SCTP_ARRAY_MIN_LEN 1
68 /* Host Name Address */
69 struct sctp_host_name_param {
70 	struct sctp_paramhdr ph;/* type=SCTP_HOSTNAME_ADDRESS */
71 	char name[SCTP_ARRAY_MIN_LEN];	/* host name */
72 }                    SCTP_PACKED;
73 
74 /*
75  * This is the maximum padded size of a s-a-p
76  * so paramheadr + 3 address types (6 bytes) + 2 byte pad = 12
77  */
78 #define SCTP_MAX_ADDR_PARAMS_SIZE 12
79 /* supported address type */
80 struct sctp_supported_addr_param {
81 	struct sctp_paramhdr ph;/* type=SCTP_SUPPORTED_ADDRTYPE */
82 	uint16_t addr_type[SCTP_ARRAY_MIN_LEN];	/* array of supported address
83 						 * types */
84 }                         SCTP_PACKED;
85 
86 /* ECN parameter */
87 struct sctp_ecn_supported_param {
88 	struct sctp_paramhdr ph;/* type=SCTP_ECN_CAPABLE */
89 }                        SCTP_PACKED;
90 
91 
92 /* heartbeat info parameter */
93 struct sctp_heartbeat_info_param {
94 	struct sctp_paramhdr ph;
95 	uint32_t time_value_1;
96 	uint32_t time_value_2;
97 	uint32_t random_value1;
98 	uint32_t random_value2;
99 	uint16_t user_req;
100 	uint8_t addr_family;
101 	uint8_t addr_len;
102 	char address[SCTP_ADDRMAX];
103 }                         SCTP_PACKED;
104 
105 
106 /* draft-ietf-tsvwg-prsctp */
107 /* PR-SCTP supported parameter */
108 struct sctp_prsctp_supported_param {
109 	struct sctp_paramhdr ph;
110 }                           SCTP_PACKED;
111 
112 
113 /* draft-ietf-tsvwg-addip-sctp */
114 struct sctp_asconf_paramhdr {	/* an ASCONF "parameter" */
115 	struct sctp_paramhdr ph;/* a SCTP parameter header */
116 	uint32_t correlation_id;/* correlation id for this param */
117 }                    SCTP_PACKED;
118 
119 struct sctp_asconf_addr_param {	/* an ASCONF address parameter */
120 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
121 	struct sctp_ipv6addr_param addrp;	/* max storage size */
122 }                      SCTP_PACKED;
123 
124 
125 struct sctp_asconf_tag_param {	/* an ASCONF NAT-Vtag parameter */
126 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
127 	uint32_t local_vtag;
128 	uint32_t remote_vtag;
129 }                     SCTP_PACKED;
130 
131 
132 struct sctp_asconf_addrv4_param {	/* an ASCONF address (v4) parameter */
133 	struct sctp_asconf_paramhdr aph;	/* asconf "parameter" */
134 	struct sctp_ipv4addr_param addrp;	/* max storage size */
135 }                        SCTP_PACKED;
136 
137 #define SCTP_MAX_SUPPORTED_EXT 256
138 
139 struct sctp_supported_chunk_types_param {
140 	struct sctp_paramhdr ph;/* type = 0x8008  len = x */
141 	uint8_t chunk_types[0];
142 }                                SCTP_PACKED;
143 
144 
145 /* ECN Nonce: draft-ladha-sctp-ecn-nonce */
146 struct sctp_ecn_nonce_supported_param {
147 	struct sctp_paramhdr ph;/* type = 0x8001  len = 4 */
148 }                              SCTP_PACKED;
149 
150 
151 /*
152  * Structures for DATA chunks
153  */
154 struct sctp_data {
155 	uint32_t tsn;
156 	uint16_t stream_id;
157 	uint16_t stream_sequence;
158 	uint32_t protocol_id;
159 	/* user data follows */
160 }         SCTP_PACKED;
161 
162 struct sctp_data_chunk {
163 	struct sctp_chunkhdr ch;
164 	struct sctp_data dp;
165 }               SCTP_PACKED;
166 
167 /*
168  * Structures for the control chunks
169  */
170 
171 /* Initiate (INIT)/Initiate Ack (INIT ACK) */
172 struct sctp_init {
173 	uint32_t initiate_tag;	/* initiate tag */
174 	uint32_t a_rwnd;	/* a_rwnd */
175 	uint16_t num_outbound_streams;	/* OS */
176 	uint16_t num_inbound_streams;	/* MIS */
177 	uint32_t initial_tsn;	/* I-TSN */
178 	/* optional param's follow */
179 }         SCTP_PACKED;
180 
181 #define SCTP_IDENTIFICATION_SIZE 16
182 #define SCTP_ADDRESS_SIZE 4
183 #define SCTP_RESERVE_SPACE 6
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 reserved[SCTP_RESERVE_SPACE];	/* Align to 64 bits */
211 	/*
212 	 * at the end is tacked on the INIT chunk and the INIT-ACK chunk
213 	 * (minus the cookie).
214 	 */
215 }                 SCTP_PACKED;
216 
217 
218 /* Used for NAT state error cause */
219 struct sctp_missing_nat_state {
220 	uint16_t cause;
221 	uint16_t length;
222 	uint8_t data[0];
223 }                      SCTP_PACKED;
224 
225 
226 struct sctp_inv_mandatory_param {
227 	uint16_t cause;
228 	uint16_t length;
229 	uint32_t num_param;
230 	uint16_t param;
231 	/*
232 	 * We include this to 0 it since only a missing cookie will cause
233 	 * this error.
234 	 */
235 	uint16_t resv;
236 }                        SCTP_PACKED;
237 
238 struct sctp_unresolv_addr {
239 	uint16_t cause;
240 	uint16_t length;
241 	uint16_t addr_type;
242 	uint16_t reserved;	/* Only one invalid addr type */
243 }                  SCTP_PACKED;
244 
245 /* state cookie parameter */
246 struct sctp_state_cookie_param {
247 	struct sctp_paramhdr ph;
248 	struct sctp_state_cookie cookie;
249 }                       SCTP_PACKED;
250 
251 struct sctp_init_chunk {
252 	struct sctp_chunkhdr ch;
253 	struct sctp_init init;
254 }               SCTP_PACKED;
255 
256 struct sctp_init_msg {
257 	struct sctphdr sh;
258 	struct sctp_init_chunk msg;
259 }             SCTP_PACKED;
260 
261 /* ... used for both INIT and INIT ACK */
262 #define sctp_init_ack		sctp_init
263 #define sctp_init_ack_chunk	sctp_init_chunk
264 #define sctp_init_ack_msg	sctp_init_msg
265 
266 
267 /* Selective Ack (SACK) */
268 struct sctp_gap_ack_block {
269 	uint16_t start;		/* Gap Ack block start */
270 	uint16_t end;		/* Gap Ack block end */
271 }                  SCTP_PACKED;
272 
273 struct sctp_sack {
274 	uint32_t cum_tsn_ack;	/* cumulative TSN Ack */
275 	uint32_t a_rwnd;	/* updated a_rwnd of sender */
276 	uint16_t num_gap_ack_blks;	/* number of Gap Ack blocks */
277 	uint16_t num_dup_tsns;	/* number of duplicate TSNs */
278 	/* struct sctp_gap_ack_block's follow */
279 	/* uint32_t duplicate_tsn's follow */
280 }         SCTP_PACKED;
281 
282 struct sctp_sack_chunk {
283 	struct sctp_chunkhdr ch;
284 	struct sctp_sack sack;
285 }               SCTP_PACKED;
286 
287 
288 /* EY Following 3 structs define NR Selective Ack (NR_SACK) chunk */
289 struct sctp_nr_gap_ack_block {
290 	uint16_t start;		/* NR Gap Ack block start */
291 	uint16_t end;		/* NR Gap Ack block end */
292 }                     SCTP_PACKED;
293 
294 struct sctp_nr_sack {
295 	uint32_t cum_tsn_ack;	/* cumulative TSN Ack */
296 	uint32_t a_rwnd;	/* updated a_rwnd of sender */
297 	uint16_t num_gap_ack_blks;	/* number of Gap Ack blocks */
298 	uint16_t num_nr_gap_ack_blks;	/* number of NR Gap Ack blocks */
299 	uint16_t num_dup_tsns;	/* number of duplicate TSNs */
300 	uint16_t reserved;	/* not currently used */
301 	/* struct sctp_gap_ack_block's follow */
302 	/* struct sctp_nr_gap_ack_block's follow */
303 	/* uint32_t duplicate_tsn's follow */
304 }            SCTP_PACKED;
305 
306 struct sctp_nr_sack_chunk {
307 	struct sctp_chunkhdr ch;
308 	struct sctp_nr_sack nr_sack;
309 }                  SCTP_PACKED;
310 
311 
312 /* Heartbeat Request (HEARTBEAT) */
313 struct sctp_heartbeat {
314 	struct sctp_heartbeat_info_param hb_info;
315 }              SCTP_PACKED;
316 
317 struct sctp_heartbeat_chunk {
318 	struct sctp_chunkhdr ch;
319 	struct sctp_heartbeat heartbeat;
320 }                    SCTP_PACKED;
321 
322 /* ... used for Heartbeat Ack (HEARTBEAT ACK) */
323 #define sctp_heartbeat_ack		sctp_heartbeat
324 #define sctp_heartbeat_ack_chunk	sctp_heartbeat_chunk
325 
326 
327 /* Abort Asssociation (ABORT) */
328 struct sctp_abort_chunk {
329 	struct sctp_chunkhdr ch;
330 	/* optional error cause may follow */
331 }                SCTP_PACKED;
332 
333 struct sctp_abort_msg {
334 	struct sctphdr sh;
335 	struct sctp_abort_chunk msg;
336 }              SCTP_PACKED;
337 
338 
339 /* Shutdown Association (SHUTDOWN) */
340 struct sctp_shutdown_chunk {
341 	struct sctp_chunkhdr ch;
342 	uint32_t cumulative_tsn_ack;
343 }                   SCTP_PACKED;
344 
345 
346 /* Shutdown Acknowledgment (SHUTDOWN ACK) */
347 struct sctp_shutdown_ack_chunk {
348 	struct sctp_chunkhdr ch;
349 }                       SCTP_PACKED;
350 
351 
352 /* Operation Error (ERROR) */
353 struct sctp_error_chunk {
354 	struct sctp_chunkhdr ch;
355 	/* optional error causes follow */
356 }                SCTP_PACKED;
357 
358 
359 /* Cookie Echo (COOKIE ECHO) */
360 struct sctp_cookie_echo_chunk {
361 	struct sctp_chunkhdr ch;
362 	struct sctp_state_cookie cookie;
363 }                      SCTP_PACKED;
364 
365 /* Cookie Acknowledgment (COOKIE ACK) */
366 struct sctp_cookie_ack_chunk {
367 	struct sctp_chunkhdr ch;
368 }                     SCTP_PACKED;
369 
370 /* Explicit Congestion Notification Echo (ECNE) */
371 struct sctp_ecne_chunk {
372 	struct sctp_chunkhdr ch;
373 	uint32_t tsn;
374 }               SCTP_PACKED;
375 
376 /* Congestion Window Reduced (CWR) */
377 struct sctp_cwr_chunk {
378 	struct sctp_chunkhdr ch;
379 	uint32_t tsn;
380 }              SCTP_PACKED;
381 
382 /* Shutdown Complete (SHUTDOWN COMPLETE) */
383 struct sctp_shutdown_complete_chunk {
384 	struct sctp_chunkhdr ch;
385 }                            SCTP_PACKED;
386 
387 /* Oper error holding a stale cookie */
388 struct sctp_stale_cookie_msg {
389 	struct sctp_paramhdr ph;/* really an error cause */
390 	uint32_t time_usec;
391 }                     SCTP_PACKED;
392 
393 struct sctp_adaptation_layer_indication {
394 	struct sctp_paramhdr ph;
395 	uint32_t indication;
396 }                                SCTP_PACKED;
397 
398 struct sctp_cookie_while_shutting_down {
399 	struct sctphdr sh;
400 	struct sctp_chunkhdr ch;
401 	struct sctp_paramhdr ph;/* really an error cause */
402 }                               SCTP_PACKED;
403 
404 struct sctp_shutdown_complete_msg {
405 	struct sctphdr sh;
406 	struct sctp_shutdown_complete_chunk shut_cmp;
407 }                          SCTP_PACKED;
408 
409 /*
410  * draft-ietf-tsvwg-addip-sctp
411  */
412 /* Address/Stream Configuration Change (ASCONF) */
413 struct sctp_asconf_chunk {
414 	struct sctp_chunkhdr ch;
415 	uint32_t serial_number;
416 	/* lookup address parameter (mandatory) */
417 	/* asconf parameters follow */
418 }                 SCTP_PACKED;
419 
420 /* Address/Stream Configuration Acknowledge (ASCONF ACK) */
421 struct sctp_asconf_ack_chunk {
422 	struct sctp_chunkhdr ch;
423 	uint32_t serial_number;
424 	/* asconf parameters follow */
425 }                     SCTP_PACKED;
426 
427 /* draft-ietf-tsvwg-prsctp */
428 /* Forward Cumulative TSN (FORWARD TSN) */
429 struct sctp_forward_tsn_chunk {
430 	struct sctp_chunkhdr ch;
431 	uint32_t new_cumulative_tsn;
432 	/* stream/sequence pairs (sctp_strseq) follow */
433 }                      SCTP_PACKED;
434 
435 struct sctp_strseq {
436 	uint16_t stream;
437 	uint16_t sequence;
438 }           SCTP_PACKED;
439 
440 struct sctp_forward_tsn_msg {
441 	struct sctphdr sh;
442 	struct sctp_forward_tsn_chunk msg;
443 }                    SCTP_PACKED;
444 
445 /* should be a multiple of 4 - 1 aka 3/7/11 etc. */
446 
447 #define SCTP_NUM_DB_TO_VERIFY 31
448 
449 struct sctp_chunk_desc {
450 	uint8_t chunk_type;
451 	uint8_t data_bytes[SCTP_NUM_DB_TO_VERIFY];
452 	uint32_t tsn_ifany;
453 }               SCTP_PACKED;
454 
455 
456 struct sctp_pktdrop_chunk {
457 	struct sctp_chunkhdr ch;
458 	uint32_t bottle_bw;
459 	uint32_t current_onq;
460 	uint16_t trunc_len;
461 	uint16_t reserved;
462 	uint8_t data[0];
463 }                  SCTP_PACKED;
464 
465 /**********STREAM RESET STUFF ******************/
466 
467 struct sctp_stream_reset_out_request {
468 	struct sctp_paramhdr ph;
469 	uint32_t request_seq;	/* monotonically increasing seq no */
470 	uint32_t response_seq;	/* if a response, the resp seq no */
471 	uint32_t send_reset_at_tsn;	/* last TSN I assigned outbound */
472 	uint16_t list_of_streams[0];	/* if not all list of streams */
473 }                             SCTP_PACKED;
474 
475 struct sctp_stream_reset_in_request {
476 	struct sctp_paramhdr ph;
477 	uint32_t request_seq;
478 	uint16_t list_of_streams[0];	/* if not all list of streams */
479 }                            SCTP_PACKED;
480 
481 
482 struct sctp_stream_reset_tsn_request {
483 	struct sctp_paramhdr ph;
484 	uint32_t request_seq;
485 }                             SCTP_PACKED;
486 
487 struct sctp_stream_reset_response {
488 	struct sctp_paramhdr ph;
489 	uint32_t response_seq;	/* if a response, the resp seq no */
490 	uint32_t result;
491 }                          SCTP_PACKED;
492 
493 struct sctp_stream_reset_response_tsn {
494 	struct sctp_paramhdr ph;
495 	uint32_t response_seq;	/* if a response, the resp seq no */
496 	uint32_t result;
497 	uint32_t senders_next_tsn;
498 	uint32_t receivers_next_tsn;
499 }                              SCTP_PACKED;
500 
501 struct sctp_stream_reset_add_strm {
502 	struct sctp_paramhdr ph;
503 	uint32_t request_seq;
504 	uint16_t number_of_streams;
505 	uint16_t reserved;
506 };
507 
508 #define SCTP_STREAM_RESET_NOTHING   0x00000000	/* Nothing for me to do */
509 #define SCTP_STREAM_RESET_PERFORMED 0x00000001	/* Did it */
510 #define SCTP_STREAM_RESET_DENIED    0x00000002	/* refused to do it */
511 #define SCTP_STREAM_RESET_ERROR_STR 0x00000003	/* bad Stream no */
512 #define SCTP_STREAM_RESET_TRY_LATER 0x00000004	/* collision, try again */
513 #define SCTP_STREAM_RESET_BAD_SEQNO 0x00000005	/* bad str-reset seq no */
514 
515 /*
516  * convience structures, note that if you are making a request for specific
517  * streams then the request will need to be an overlay structure.
518  */
519 
520 struct sctp_stream_reset_out_req {
521 	struct sctp_chunkhdr ch;
522 	struct sctp_stream_reset_out_request sr_req;
523 }                         SCTP_PACKED;
524 
525 struct sctp_stream_reset_in_req {
526 	struct sctp_chunkhdr ch;
527 	struct sctp_stream_reset_in_request sr_req;
528 }                        SCTP_PACKED;
529 
530 struct sctp_stream_reset_tsn_req {
531 	struct sctp_chunkhdr ch;
532 	struct sctp_stream_reset_tsn_request sr_req;
533 }                         SCTP_PACKED;
534 
535 struct sctp_stream_reset_resp {
536 	struct sctp_chunkhdr ch;
537 	struct sctp_stream_reset_response sr_resp;
538 }                      SCTP_PACKED;
539 
540 /* respone only valid with a TSN request */
541 struct sctp_stream_reset_resp_tsn {
542 	struct sctp_chunkhdr ch;
543 	struct sctp_stream_reset_response_tsn sr_resp;
544 }                          SCTP_PACKED;
545 
546 /****************************************************/
547 
548 /*
549  * Authenticated chunks support draft-ietf-tsvwg-sctp-auth
550  */
551 
552 /* Should we make the max be 32? */
553 #define SCTP_RANDOM_MAX_SIZE 256
554 struct sctp_auth_random {
555 	struct sctp_paramhdr ph;/* type = 0x8002 */
556 	uint8_t random_data[0];
557 }                SCTP_PACKED;
558 
559 struct sctp_auth_chunk_list {
560 	struct sctp_paramhdr ph;/* type = 0x8003 */
561 	uint8_t chunk_types[0];
562 }                    SCTP_PACKED;
563 
564 struct sctp_auth_hmac_algo {
565 	struct sctp_paramhdr ph;/* type = 0x8004 */
566 	uint16_t hmac_ids[0];
567 }                   SCTP_PACKED;
568 
569 struct sctp_auth_chunk {
570 	struct sctp_chunkhdr ch;
571 	uint16_t shared_key_id;
572 	uint16_t hmac_id;
573 	uint8_t hmac[0];
574 }               SCTP_PACKED;
575 
576 struct sctp_auth_invalid_hmac {
577 	struct sctp_paramhdr ph;
578 	uint16_t hmac_id;
579 	uint16_t padding;
580 }                      SCTP_PACKED;
581 
582 /*
583  * we pre-reserve enough room for a ECNE or CWR AND a SACK with no missing
584  * pieces. If ENCE is missing we could have a couple of blocks. This way we
585  * optimize so we MOST likely can bundle a SACK/ECN with the smallest size
586  * data chunk I will split into. We could increase throughput slightly by
587  * taking out these two but the  24-sack/8-CWR i.e. 32 bytes I pre-reserve I
588  * feel is worth it for now.
589  */
590 #ifndef SCTP_MAX_OVERHEAD
591 #ifdef INET6
592 #define SCTP_MAX_OVERHEAD (sizeof(struct sctp_data_chunk) + \
593 			   sizeof(struct sctphdr) + \
594 			   sizeof(struct sctp_ecne_chunk) + \
595 			   sizeof(struct sctp_sack_chunk) + \
596 			   sizeof(struct ip6_hdr))
597 
598 #define SCTP_MED_OVERHEAD (sizeof(struct sctp_data_chunk) + \
599 			   sizeof(struct sctphdr) + \
600 			   sizeof(struct ip6_hdr))
601 
602 
603 #define SCTP_MIN_OVERHEAD (sizeof(struct ip6_hdr) + \
604 			   sizeof(struct sctphdr))
605 
606 #else
607 #define SCTP_MAX_OVERHEAD (sizeof(struct sctp_data_chunk) + \
608 			   sizeof(struct sctphdr) + \
609 			   sizeof(struct sctp_ecne_chunk) + \
610 			   sizeof(struct sctp_sack_chunk) + \
611 			   sizeof(struct ip))
612 
613 #define SCTP_MED_OVERHEAD (sizeof(struct sctp_data_chunk) + \
614 			   sizeof(struct sctphdr) + \
615 			   sizeof(struct ip))
616 
617 
618 #define SCTP_MIN_OVERHEAD (sizeof(struct ip) + \
619 			   sizeof(struct sctphdr))
620 
621 #endif				/* INET6 */
622 #endif				/* !SCTP_MAX_OVERHEAD */
623 
624 #define SCTP_MED_V4_OVERHEAD (sizeof(struct sctp_data_chunk) + \
625 			      sizeof(struct sctphdr) + \
626 			      sizeof(struct ip))
627 
628 #define SCTP_MIN_V4_OVERHEAD (sizeof(struct ip) + \
629 			      sizeof(struct sctphdr))
630 
631 #undef SCTP_PACKED
632 #endif				/* !__sctp_header_h__ */
633