xref: /openbmc/linux/net/sctp/sm_make_chunk.c (revision 9a8f3203)
1 /* SCTP kernel implementation
2  * (C) Copyright IBM Corp. 2001, 2004
3  * Copyright (c) 1999-2000 Cisco, Inc.
4  * Copyright (c) 1999-2001 Motorola, Inc.
5  * Copyright (c) 2001-2002 Intel Corp.
6  *
7  * This file is part of the SCTP kernel implementation
8  *
9  * These functions work with the state functions in sctp_sm_statefuns.c
10  * to implement the state operations.  These functions implement the
11  * steps which require modifying existing data structures.
12  *
13  * This SCTP implementation is free software;
14  * you can redistribute it and/or modify it under the terms of
15  * the GNU General Public License as published by
16  * the Free Software Foundation; either version 2, or (at your option)
17  * any later version.
18  *
19  * This SCTP implementation is distributed in the hope that it
20  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
21  *                 ************************
22  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
23  * See the GNU General Public License for more details.
24  *
25  * You should have received a copy of the GNU General Public License
26  * along with GNU CC; see the file COPYING.  If not, see
27  * <http://www.gnu.org/licenses/>.
28  *
29  * Please send any bug reports or fixes you make to the
30  * email address(es):
31  *    lksctp developers <linux-sctp@vger.kernel.org>
32  *
33  * Written or modified by:
34  *    La Monte H.P. Yarroll <piggy@acm.org>
35  *    Karl Knutson          <karl@athena.chicago.il.us>
36  *    C. Robin              <chris@hundredacre.ac.uk>
37  *    Jon Grimm             <jgrimm@us.ibm.com>
38  *    Xingang Guo           <xingang.guo@intel.com>
39  *    Dajiang Zhang	    <dajiang.zhang@nokia.com>
40  *    Sridhar Samudrala	    <sri@us.ibm.com>
41  *    Daisy Chang	    <daisyc@us.ibm.com>
42  *    Ardelle Fan	    <ardelle.fan@intel.com>
43  *    Kevin Gao             <kevin.gao@intel.com>
44  */
45 
46 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
47 
48 #include <crypto/hash.h>
49 #include <linux/types.h>
50 #include <linux/kernel.h>
51 #include <linux/ip.h>
52 #include <linux/ipv6.h>
53 #include <linux/net.h>
54 #include <linux/inet.h>
55 #include <linux/scatterlist.h>
56 #include <linux/slab.h>
57 #include <net/sock.h>
58 
59 #include <linux/skbuff.h>
60 #include <linux/random.h>	/* for get_random_bytes */
61 #include <net/sctp/sctp.h>
62 #include <net/sctp/sm.h>
63 
64 static struct sctp_chunk *sctp_make_control(const struct sctp_association *asoc,
65 					    __u8 type, __u8 flags, int paylen,
66 					    gfp_t gfp);
67 static struct sctp_chunk *sctp_make_data(const struct sctp_association *asoc,
68 					 __u8 flags, int paylen, gfp_t gfp);
69 static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc,
70 					   __u8 type, __u8 flags, int paylen,
71 					   gfp_t gfp);
72 static struct sctp_cookie_param *sctp_pack_cookie(
73 					const struct sctp_endpoint *ep,
74 					const struct sctp_association *asoc,
75 					const struct sctp_chunk *init_chunk,
76 					int *cookie_len,
77 					const __u8 *raw_addrs, int addrs_len);
78 static int sctp_process_param(struct sctp_association *asoc,
79 			      union sctp_params param,
80 			      const union sctp_addr *peer_addr,
81 			      gfp_t gfp);
82 static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
83 			      const void *data);
84 
85 /* Control chunk destructor */
86 static void sctp_control_release_owner(struct sk_buff *skb)
87 {
88 	struct sctp_chunk *chunk = skb_shinfo(skb)->destructor_arg;
89 
90 	if (chunk->shkey) {
91 		struct sctp_shared_key *shkey = chunk->shkey;
92 		struct sctp_association *asoc = chunk->asoc;
93 
94 		/* refcnt == 2 and !list_empty mean after this release, it's
95 		 * not being used anywhere, and it's time to notify userland
96 		 * that this shkey can be freed if it's been deactivated.
97 		 */
98 		if (shkey->deactivated && !list_empty(&shkey->key_list) &&
99 		    refcount_read(&shkey->refcnt) == 2) {
100 			struct sctp_ulpevent *ev;
101 
102 			ev = sctp_ulpevent_make_authkey(asoc, shkey->key_id,
103 							SCTP_AUTH_FREE_KEY,
104 							GFP_KERNEL);
105 			if (ev)
106 				asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
107 		}
108 		sctp_auth_shkey_release(chunk->shkey);
109 	}
110 }
111 
112 static void sctp_control_set_owner_w(struct sctp_chunk *chunk)
113 {
114 	struct sctp_association *asoc = chunk->asoc;
115 	struct sk_buff *skb = chunk->skb;
116 
117 	/* TODO: properly account for control chunks.
118 	 * To do it right we'll need:
119 	 *  1) endpoint if association isn't known.
120 	 *  2) proper memory accounting.
121 	 *
122 	 *  For now don't do anything for now.
123 	 */
124 	if (chunk->auth) {
125 		chunk->shkey = asoc->shkey;
126 		sctp_auth_shkey_hold(chunk->shkey);
127 	}
128 	skb->sk = asoc ? asoc->base.sk : NULL;
129 	skb_shinfo(skb)->destructor_arg = chunk;
130 	skb->destructor = sctp_control_release_owner;
131 }
132 
133 /* What was the inbound interface for this chunk? */
134 int sctp_chunk_iif(const struct sctp_chunk *chunk)
135 {
136 	struct sk_buff *skb = chunk->skb;
137 
138 	return SCTP_INPUT_CB(skb)->af->skb_iif(skb);
139 }
140 
141 /* RFC 2960 3.3.2 Initiation (INIT) (1)
142  *
143  * Note 2: The ECN capable field is reserved for future use of
144  * Explicit Congestion Notification.
145  */
146 static const struct sctp_paramhdr ecap_param = {
147 	SCTP_PARAM_ECN_CAPABLE,
148 	cpu_to_be16(sizeof(struct sctp_paramhdr)),
149 };
150 static const struct sctp_paramhdr prsctp_param = {
151 	SCTP_PARAM_FWD_TSN_SUPPORT,
152 	cpu_to_be16(sizeof(struct sctp_paramhdr)),
153 };
154 
155 /* A helper to initialize an op error inside a provided chunk, as most
156  * cause codes will be embedded inside an abort chunk.
157  */
158 int sctp_init_cause(struct sctp_chunk *chunk, __be16 cause_code,
159 		    size_t paylen)
160 {
161 	struct sctp_errhdr err;
162 	__u16 len;
163 
164 	/* Cause code constants are now defined in network order.  */
165 	err.cause = cause_code;
166 	len = sizeof(err) + paylen;
167 	err.length = htons(len);
168 
169 	if (skb_tailroom(chunk->skb) < len)
170 		return -ENOSPC;
171 
172 	chunk->subh.err_hdr = sctp_addto_chunk(chunk, sizeof(err), &err);
173 
174 	return 0;
175 }
176 
177 /* 3.3.2 Initiation (INIT) (1)
178  *
179  * This chunk is used to initiate a SCTP association between two
180  * endpoints. The format of the INIT chunk is shown below:
181  *
182  *     0                   1                   2                   3
183  *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
184  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
185  *    |   Type = 1    |  Chunk Flags  |      Chunk Length             |
186  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
187  *    |                         Initiate Tag                          |
188  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
189  *    |           Advertised Receiver Window Credit (a_rwnd)          |
190  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
191  *    |  Number of Outbound Streams   |  Number of Inbound Streams    |
192  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
193  *    |                          Initial TSN                          |
194  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
195  *    \                                                               \
196  *    /              Optional/Variable-Length Parameters              /
197  *    \                                                               \
198  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
199  *
200  *
201  * The INIT chunk contains the following parameters. Unless otherwise
202  * noted, each parameter MUST only be included once in the INIT chunk.
203  *
204  * Fixed Parameters                     Status
205  * ----------------------------------------------
206  * Initiate Tag                        Mandatory
207  * Advertised Receiver Window Credit   Mandatory
208  * Number of Outbound Streams          Mandatory
209  * Number of Inbound Streams           Mandatory
210  * Initial TSN                         Mandatory
211  *
212  * Variable Parameters                  Status     Type Value
213  * -------------------------------------------------------------
214  * IPv4 Address (Note 1)               Optional    5
215  * IPv6 Address (Note 1)               Optional    6
216  * Cookie Preservative                 Optional    9
217  * Reserved for ECN Capable (Note 2)   Optional    32768 (0x8000)
218  * Host Name Address (Note 3)          Optional    11
219  * Supported Address Types (Note 4)    Optional    12
220  */
221 struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc,
222 				  const struct sctp_bind_addr *bp,
223 				  gfp_t gfp, int vparam_len)
224 {
225 	struct net *net = sock_net(asoc->base.sk);
226 	struct sctp_supported_ext_param ext_param;
227 	struct sctp_adaptation_ind_param aiparam;
228 	struct sctp_paramhdr *auth_chunks = NULL;
229 	struct sctp_paramhdr *auth_hmacs = NULL;
230 	struct sctp_supported_addrs_param sat;
231 	struct sctp_endpoint *ep = asoc->ep;
232 	struct sctp_chunk *retval = NULL;
233 	int num_types, addrs_len = 0;
234 	struct sctp_inithdr init;
235 	union sctp_params addrs;
236 	struct sctp_sock *sp;
237 	__u8 extensions[5];
238 	size_t chunksize;
239 	__be16 types[2];
240 	int num_ext = 0;
241 
242 	/* RFC 2960 3.3.2 Initiation (INIT) (1)
243 	 *
244 	 * Note 1: The INIT chunks can contain multiple addresses that
245 	 * can be IPv4 and/or IPv6 in any combination.
246 	 */
247 
248 	/* Convert the provided bind address list to raw format. */
249 	addrs = sctp_bind_addrs_to_raw(bp, &addrs_len, gfp);
250 
251 	init.init_tag		   = htonl(asoc->c.my_vtag);
252 	init.a_rwnd		   = htonl(asoc->rwnd);
253 	init.num_outbound_streams  = htons(asoc->c.sinit_num_ostreams);
254 	init.num_inbound_streams   = htons(asoc->c.sinit_max_instreams);
255 	init.initial_tsn	   = htonl(asoc->c.initial_tsn);
256 
257 	/* How many address types are needed? */
258 	sp = sctp_sk(asoc->base.sk);
259 	num_types = sp->pf->supported_addrs(sp, types);
260 
261 	chunksize = sizeof(init) + addrs_len;
262 	chunksize += SCTP_PAD4(SCTP_SAT_LEN(num_types));
263 	chunksize += sizeof(ecap_param);
264 
265 	if (asoc->prsctp_enable)
266 		chunksize += sizeof(prsctp_param);
267 
268 	/* ADDIP: Section 4.2.7:
269 	 *  An implementation supporting this extension [ADDIP] MUST list
270 	 *  the ASCONF,the ASCONF-ACK, and the AUTH  chunks in its INIT and
271 	 *  INIT-ACK parameters.
272 	 */
273 	if (net->sctp.addip_enable) {
274 		extensions[num_ext] = SCTP_CID_ASCONF;
275 		extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
276 		num_ext += 2;
277 	}
278 
279 	if (asoc->reconf_enable) {
280 		extensions[num_ext] = SCTP_CID_RECONF;
281 		num_ext += 1;
282 	}
283 
284 	if (sp->adaptation_ind)
285 		chunksize += sizeof(aiparam);
286 
287 	if (sp->strm_interleave) {
288 		extensions[num_ext] = SCTP_CID_I_DATA;
289 		num_ext += 1;
290 	}
291 
292 	chunksize += vparam_len;
293 
294 	/* Account for AUTH related parameters */
295 	if (ep->auth_enable) {
296 		/* Add random parameter length*/
297 		chunksize += sizeof(asoc->c.auth_random);
298 
299 		/* Add HMACS parameter length if any were defined */
300 		auth_hmacs = (struct sctp_paramhdr *)asoc->c.auth_hmacs;
301 		if (auth_hmacs->length)
302 			chunksize += SCTP_PAD4(ntohs(auth_hmacs->length));
303 		else
304 			auth_hmacs = NULL;
305 
306 		/* Add CHUNKS parameter length */
307 		auth_chunks = (struct sctp_paramhdr *)asoc->c.auth_chunks;
308 		if (auth_chunks->length)
309 			chunksize += SCTP_PAD4(ntohs(auth_chunks->length));
310 		else
311 			auth_chunks = NULL;
312 
313 		extensions[num_ext] = SCTP_CID_AUTH;
314 		num_ext += 1;
315 	}
316 
317 	/* If we have any extensions to report, account for that */
318 	if (num_ext)
319 		chunksize += SCTP_PAD4(sizeof(ext_param) + num_ext);
320 
321 	/* RFC 2960 3.3.2 Initiation (INIT) (1)
322 	 *
323 	 * Note 3: An INIT chunk MUST NOT contain more than one Host
324 	 * Name address parameter. Moreover, the sender of the INIT
325 	 * MUST NOT combine any other address types with the Host Name
326 	 * address in the INIT. The receiver of INIT MUST ignore any
327 	 * other address types if the Host Name address parameter is
328 	 * present in the received INIT chunk.
329 	 *
330 	 * PLEASE DO NOT FIXME [This version does not support Host Name.]
331 	 */
332 
333 	retval = sctp_make_control(asoc, SCTP_CID_INIT, 0, chunksize, gfp);
334 	if (!retval)
335 		goto nodata;
336 
337 	retval->subh.init_hdr =
338 		sctp_addto_chunk(retval, sizeof(init), &init);
339 	retval->param_hdr.v =
340 		sctp_addto_chunk(retval, addrs_len, addrs.v);
341 
342 	/* RFC 2960 3.3.2 Initiation (INIT) (1)
343 	 *
344 	 * Note 4: This parameter, when present, specifies all the
345 	 * address types the sending endpoint can support. The absence
346 	 * of this parameter indicates that the sending endpoint can
347 	 * support any address type.
348 	 */
349 	sat.param_hdr.type = SCTP_PARAM_SUPPORTED_ADDRESS_TYPES;
350 	sat.param_hdr.length = htons(SCTP_SAT_LEN(num_types));
351 	sctp_addto_chunk(retval, sizeof(sat), &sat);
352 	sctp_addto_chunk(retval, num_types * sizeof(__u16), &types);
353 
354 	sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
355 
356 	/* Add the supported extensions parameter.  Be nice and add this
357 	 * fist before addiding the parameters for the extensions themselves
358 	 */
359 	if (num_ext) {
360 		ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
361 		ext_param.param_hdr.length = htons(sizeof(ext_param) + num_ext);
362 		sctp_addto_chunk(retval, sizeof(ext_param), &ext_param);
363 		sctp_addto_param(retval, num_ext, extensions);
364 	}
365 
366 	if (asoc->prsctp_enable)
367 		sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
368 
369 	if (sp->adaptation_ind) {
370 		aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
371 		aiparam.param_hdr.length = htons(sizeof(aiparam));
372 		aiparam.adaptation_ind = htonl(sp->adaptation_ind);
373 		sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
374 	}
375 
376 	/* Add SCTP-AUTH chunks to the parameter list */
377 	if (ep->auth_enable) {
378 		sctp_addto_chunk(retval, sizeof(asoc->c.auth_random),
379 				 asoc->c.auth_random);
380 		if (auth_hmacs)
381 			sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
382 					auth_hmacs);
383 		if (auth_chunks)
384 			sctp_addto_chunk(retval, ntohs(auth_chunks->length),
385 					auth_chunks);
386 	}
387 nodata:
388 	kfree(addrs.v);
389 	return retval;
390 }
391 
392 struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc,
393 				      const struct sctp_chunk *chunk,
394 				      gfp_t gfp, int unkparam_len)
395 {
396 	struct sctp_supported_ext_param ext_param;
397 	struct sctp_adaptation_ind_param aiparam;
398 	struct sctp_paramhdr *auth_chunks = NULL;
399 	struct sctp_paramhdr *auth_random = NULL;
400 	struct sctp_paramhdr *auth_hmacs = NULL;
401 	struct sctp_chunk *retval = NULL;
402 	struct sctp_cookie_param *cookie;
403 	struct sctp_inithdr initack;
404 	union sctp_params addrs;
405 	struct sctp_sock *sp;
406 	__u8 extensions[5];
407 	size_t chunksize;
408 	int num_ext = 0;
409 	int cookie_len;
410 	int addrs_len;
411 
412 	/* Note: there may be no addresses to embed. */
413 	addrs = sctp_bind_addrs_to_raw(&asoc->base.bind_addr, &addrs_len, gfp);
414 
415 	initack.init_tag	        = htonl(asoc->c.my_vtag);
416 	initack.a_rwnd			= htonl(asoc->rwnd);
417 	initack.num_outbound_streams	= htons(asoc->c.sinit_num_ostreams);
418 	initack.num_inbound_streams	= htons(asoc->c.sinit_max_instreams);
419 	initack.initial_tsn		= htonl(asoc->c.initial_tsn);
420 
421 	/* FIXME:  We really ought to build the cookie right
422 	 * into the packet instead of allocating more fresh memory.
423 	 */
424 	cookie = sctp_pack_cookie(asoc->ep, asoc, chunk, &cookie_len,
425 				  addrs.v, addrs_len);
426 	if (!cookie)
427 		goto nomem_cookie;
428 
429 	/* Calculate the total size of allocation, include the reserved
430 	 * space for reporting unknown parameters if it is specified.
431 	 */
432 	sp = sctp_sk(asoc->base.sk);
433 	chunksize = sizeof(initack) + addrs_len + cookie_len + unkparam_len;
434 
435 	/* Tell peer that we'll do ECN only if peer advertised such cap.  */
436 	if (asoc->peer.ecn_capable)
437 		chunksize += sizeof(ecap_param);
438 
439 	if (asoc->peer.prsctp_capable)
440 		chunksize += sizeof(prsctp_param);
441 
442 	if (asoc->peer.asconf_capable) {
443 		extensions[num_ext] = SCTP_CID_ASCONF;
444 		extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
445 		num_ext += 2;
446 	}
447 
448 	if (asoc->peer.reconf_capable) {
449 		extensions[num_ext] = SCTP_CID_RECONF;
450 		num_ext += 1;
451 	}
452 
453 	if (sp->adaptation_ind)
454 		chunksize += sizeof(aiparam);
455 
456 	if (asoc->intl_enable) {
457 		extensions[num_ext] = SCTP_CID_I_DATA;
458 		num_ext += 1;
459 	}
460 
461 	if (asoc->peer.auth_capable) {
462 		auth_random = (struct sctp_paramhdr *)asoc->c.auth_random;
463 		chunksize += ntohs(auth_random->length);
464 
465 		auth_hmacs = (struct sctp_paramhdr *)asoc->c.auth_hmacs;
466 		if (auth_hmacs->length)
467 			chunksize += SCTP_PAD4(ntohs(auth_hmacs->length));
468 		else
469 			auth_hmacs = NULL;
470 
471 		auth_chunks = (struct sctp_paramhdr *)asoc->c.auth_chunks;
472 		if (auth_chunks->length)
473 			chunksize += SCTP_PAD4(ntohs(auth_chunks->length));
474 		else
475 			auth_chunks = NULL;
476 
477 		extensions[num_ext] = SCTP_CID_AUTH;
478 		num_ext += 1;
479 	}
480 
481 	if (num_ext)
482 		chunksize += SCTP_PAD4(sizeof(ext_param) + num_ext);
483 
484 	/* Now allocate and fill out the chunk.  */
485 	retval = sctp_make_control(asoc, SCTP_CID_INIT_ACK, 0, chunksize, gfp);
486 	if (!retval)
487 		goto nomem_chunk;
488 
489 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
490 	 *
491 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
492 	 * HEARTBEAT ACK, * etc.) to the same destination transport
493 	 * address from which it received the DATA or control chunk
494 	 * to which it is replying.
495 	 *
496 	 * [INIT ACK back to where the INIT came from.]
497 	 */
498 	if (chunk->transport)
499 		retval->transport =
500 			sctp_assoc_lookup_paddr(asoc,
501 						&chunk->transport->ipaddr);
502 
503 	retval->subh.init_hdr =
504 		sctp_addto_chunk(retval, sizeof(initack), &initack);
505 	retval->param_hdr.v = sctp_addto_chunk(retval, addrs_len, addrs.v);
506 	sctp_addto_chunk(retval, cookie_len, cookie);
507 	if (asoc->peer.ecn_capable)
508 		sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
509 	if (num_ext) {
510 		ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
511 		ext_param.param_hdr.length = htons(sizeof(ext_param) + num_ext);
512 		sctp_addto_chunk(retval, sizeof(ext_param), &ext_param);
513 		sctp_addto_param(retval, num_ext, extensions);
514 	}
515 	if (asoc->peer.prsctp_capable)
516 		sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
517 
518 	if (sp->adaptation_ind) {
519 		aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
520 		aiparam.param_hdr.length = htons(sizeof(aiparam));
521 		aiparam.adaptation_ind = htonl(sp->adaptation_ind);
522 		sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
523 	}
524 
525 	if (asoc->peer.auth_capable) {
526 		sctp_addto_chunk(retval, ntohs(auth_random->length),
527 				 auth_random);
528 		if (auth_hmacs)
529 			sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
530 					auth_hmacs);
531 		if (auth_chunks)
532 			sctp_addto_chunk(retval, ntohs(auth_chunks->length),
533 					auth_chunks);
534 	}
535 
536 	/* We need to remove the const qualifier at this point.  */
537 	retval->asoc = (struct sctp_association *) asoc;
538 
539 nomem_chunk:
540 	kfree(cookie);
541 nomem_cookie:
542 	kfree(addrs.v);
543 	return retval;
544 }
545 
546 /* 3.3.11 Cookie Echo (COOKIE ECHO) (10):
547  *
548  * This chunk is used only during the initialization of an association.
549  * It is sent by the initiator of an association to its peer to complete
550  * the initialization process. This chunk MUST precede any DATA chunk
551  * sent within the association, but MAY be bundled with one or more DATA
552  * chunks in the same packet.
553  *
554  *      0                   1                   2                   3
555  *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
556  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
557  *     |   Type = 10   |Chunk  Flags   |         Length                |
558  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
559  *     /                     Cookie                                    /
560  *     \                                                               \
561  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
562  *
563  * Chunk Flags: 8 bit
564  *
565  *   Set to zero on transmit and ignored on receipt.
566  *
567  * Length: 16 bits (unsigned integer)
568  *
569  *   Set to the size of the chunk in bytes, including the 4 bytes of
570  *   the chunk header and the size of the Cookie.
571  *
572  * Cookie: variable size
573  *
574  *   This field must contain the exact cookie received in the
575  *   State Cookie parameter from the previous INIT ACK.
576  *
577  *   An implementation SHOULD make the cookie as small as possible
578  *   to insure interoperability.
579  */
580 struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *asoc,
581 					 const struct sctp_chunk *chunk)
582 {
583 	struct sctp_chunk *retval;
584 	int cookie_len;
585 	void *cookie;
586 
587 	cookie = asoc->peer.cookie;
588 	cookie_len = asoc->peer.cookie_len;
589 
590 	/* Build a cookie echo chunk.  */
591 	retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ECHO, 0,
592 				   cookie_len, GFP_ATOMIC);
593 	if (!retval)
594 		goto nodata;
595 	retval->subh.cookie_hdr =
596 		sctp_addto_chunk(retval, cookie_len, cookie);
597 
598 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
599 	 *
600 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
601 	 * HEARTBEAT ACK, * etc.) to the same destination transport
602 	 * address from which it * received the DATA or control chunk
603 	 * to which it is replying.
604 	 *
605 	 * [COOKIE ECHO back to where the INIT ACK came from.]
606 	 */
607 	if (chunk)
608 		retval->transport = chunk->transport;
609 
610 nodata:
611 	return retval;
612 }
613 
614 /* 3.3.12 Cookie Acknowledgement (COOKIE ACK) (11):
615  *
616  * This chunk is used only during the initialization of an
617  * association.  It is used to acknowledge the receipt of a COOKIE
618  * ECHO chunk.  This chunk MUST precede any DATA or SACK chunk sent
619  * within the association, but MAY be bundled with one or more DATA
620  * chunks or SACK chunk in the same SCTP packet.
621  *
622  *      0                   1                   2                   3
623  *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
624  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
625  *     |   Type = 11   |Chunk  Flags   |     Length = 4                |
626  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
627  *
628  * Chunk Flags: 8 bits
629  *
630  *   Set to zero on transmit and ignored on receipt.
631  */
632 struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *asoc,
633 					const struct sctp_chunk *chunk)
634 {
635 	struct sctp_chunk *retval;
636 
637 	retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ACK, 0, 0, GFP_ATOMIC);
638 
639 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
640 	 *
641 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
642 	 * HEARTBEAT ACK, * etc.) to the same destination transport
643 	 * address from which it * received the DATA or control chunk
644 	 * to which it is replying.
645 	 *
646 	 * [COOKIE ACK back to where the COOKIE ECHO came from.]
647 	 */
648 	if (retval && chunk && chunk->transport)
649 		retval->transport =
650 			sctp_assoc_lookup_paddr(asoc,
651 						&chunk->transport->ipaddr);
652 
653 	return retval;
654 }
655 
656 /*
657  *  Appendix A: Explicit Congestion Notification:
658  *  CWR:
659  *
660  *  RFC 2481 details a specific bit for a sender to send in the header of
661  *  its next outbound TCP segment to indicate to its peer that it has
662  *  reduced its congestion window.  This is termed the CWR bit.  For
663  *  SCTP the same indication is made by including the CWR chunk.
664  *  This chunk contains one data element, i.e. the TSN number that
665  *  was sent in the ECNE chunk.  This element represents the lowest
666  *  TSN number in the datagram that was originally marked with the
667  *  CE bit.
668  *
669  *     0                   1                   2                   3
670  *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
671  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
672  *    | Chunk Type=13 | Flags=00000000|    Chunk Length = 8           |
673  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
674  *    |                      Lowest TSN Number                        |
675  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
676  *
677  *     Note: The CWR is considered a Control chunk.
678  */
679 struct sctp_chunk *sctp_make_cwr(const struct sctp_association *asoc,
680 				 const __u32 lowest_tsn,
681 				 const struct sctp_chunk *chunk)
682 {
683 	struct sctp_chunk *retval;
684 	struct sctp_cwrhdr cwr;
685 
686 	cwr.lowest_tsn = htonl(lowest_tsn);
687 	retval = sctp_make_control(asoc, SCTP_CID_ECN_CWR, 0,
688 				   sizeof(cwr), GFP_ATOMIC);
689 
690 	if (!retval)
691 		goto nodata;
692 
693 	retval->subh.ecn_cwr_hdr =
694 		sctp_addto_chunk(retval, sizeof(cwr), &cwr);
695 
696 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
697 	 *
698 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
699 	 * HEARTBEAT ACK, * etc.) to the same destination transport
700 	 * address from which it * received the DATA or control chunk
701 	 * to which it is replying.
702 	 *
703 	 * [Report a reduced congestion window back to where the ECNE
704 	 * came from.]
705 	 */
706 	if (chunk)
707 		retval->transport = chunk->transport;
708 
709 nodata:
710 	return retval;
711 }
712 
713 /* Make an ECNE chunk.  This is a congestion experienced report.  */
714 struct sctp_chunk *sctp_make_ecne(const struct sctp_association *asoc,
715 				  const __u32 lowest_tsn)
716 {
717 	struct sctp_chunk *retval;
718 	struct sctp_ecnehdr ecne;
719 
720 	ecne.lowest_tsn = htonl(lowest_tsn);
721 	retval = sctp_make_control(asoc, SCTP_CID_ECN_ECNE, 0,
722 				   sizeof(ecne), GFP_ATOMIC);
723 	if (!retval)
724 		goto nodata;
725 	retval->subh.ecne_hdr =
726 		sctp_addto_chunk(retval, sizeof(ecne), &ecne);
727 
728 nodata:
729 	return retval;
730 }
731 
732 /* Make a DATA chunk for the given association from the provided
733  * parameters.  However, do not populate the data payload.
734  */
735 struct sctp_chunk *sctp_make_datafrag_empty(const struct sctp_association *asoc,
736 					    const struct sctp_sndrcvinfo *sinfo,
737 					    int len, __u8 flags, gfp_t gfp)
738 {
739 	struct sctp_chunk *retval;
740 	struct sctp_datahdr dp;
741 
742 	/* We assign the TSN as LATE as possible, not here when
743 	 * creating the chunk.
744 	 */
745 	memset(&dp, 0, sizeof(dp));
746 	dp.ppid = sinfo->sinfo_ppid;
747 	dp.stream = htons(sinfo->sinfo_stream);
748 
749 	/* Set the flags for an unordered send.  */
750 	if (sinfo->sinfo_flags & SCTP_UNORDERED)
751 		flags |= SCTP_DATA_UNORDERED;
752 
753 	retval = sctp_make_data(asoc, flags, sizeof(dp) + len, gfp);
754 	if (!retval)
755 		return NULL;
756 
757 	retval->subh.data_hdr = sctp_addto_chunk(retval, sizeof(dp), &dp);
758 	memcpy(&retval->sinfo, sinfo, sizeof(struct sctp_sndrcvinfo));
759 
760 	return retval;
761 }
762 
763 /* Create a selective ackowledgement (SACK) for the given
764  * association.  This reports on which TSN's we've seen to date,
765  * including duplicates and gaps.
766  */
767 struct sctp_chunk *sctp_make_sack(struct sctp_association *asoc)
768 {
769 	struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
770 	struct sctp_gap_ack_block gabs[SCTP_MAX_GABS];
771 	__u16 num_gabs, num_dup_tsns;
772 	struct sctp_transport *trans;
773 	struct sctp_chunk *retval;
774 	struct sctp_sackhdr sack;
775 	__u32 ctsn;
776 	int len;
777 
778 	memset(gabs, 0, sizeof(gabs));
779 	ctsn = sctp_tsnmap_get_ctsn(map);
780 
781 	pr_debug("%s: sackCTSNAck sent:0x%x\n", __func__, ctsn);
782 
783 	/* How much room is needed in the chunk? */
784 	num_gabs = sctp_tsnmap_num_gabs(map, gabs);
785 	num_dup_tsns = sctp_tsnmap_num_dups(map);
786 
787 	/* Initialize the SACK header.  */
788 	sack.cum_tsn_ack	    = htonl(ctsn);
789 	sack.a_rwnd 		    = htonl(asoc->a_rwnd);
790 	sack.num_gap_ack_blocks     = htons(num_gabs);
791 	sack.num_dup_tsns           = htons(num_dup_tsns);
792 
793 	len = sizeof(sack)
794 		+ sizeof(struct sctp_gap_ack_block) * num_gabs
795 		+ sizeof(__u32) * num_dup_tsns;
796 
797 	/* Create the chunk.  */
798 	retval = sctp_make_control(asoc, SCTP_CID_SACK, 0, len, GFP_ATOMIC);
799 	if (!retval)
800 		goto nodata;
801 
802 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
803 	 *
804 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
805 	 * HEARTBEAT ACK, etc.) to the same destination transport
806 	 * address from which it received the DATA or control chunk to
807 	 * which it is replying.  This rule should also be followed if
808 	 * the endpoint is bundling DATA chunks together with the
809 	 * reply chunk.
810 	 *
811 	 * However, when acknowledging multiple DATA chunks received
812 	 * in packets from different source addresses in a single
813 	 * SACK, the SACK chunk may be transmitted to one of the
814 	 * destination transport addresses from which the DATA or
815 	 * control chunks being acknowledged were received.
816 	 *
817 	 * [BUG:  We do not implement the following paragraph.
818 	 * Perhaps we should remember the last transport we used for a
819 	 * SACK and avoid that (if possible) if we have seen any
820 	 * duplicates. --piggy]
821 	 *
822 	 * When a receiver of a duplicate DATA chunk sends a SACK to a
823 	 * multi- homed endpoint it MAY be beneficial to vary the
824 	 * destination address and not use the source address of the
825 	 * DATA chunk.  The reason being that receiving a duplicate
826 	 * from a multi-homed endpoint might indicate that the return
827 	 * path (as specified in the source address of the DATA chunk)
828 	 * for the SACK is broken.
829 	 *
830 	 * [Send to the address from which we last received a DATA chunk.]
831 	 */
832 	retval->transport = asoc->peer.last_data_from;
833 
834 	retval->subh.sack_hdr =
835 		sctp_addto_chunk(retval, sizeof(sack), &sack);
836 
837 	/* Add the gap ack block information.   */
838 	if (num_gabs)
839 		sctp_addto_chunk(retval, sizeof(__u32) * num_gabs,
840 				 gabs);
841 
842 	/* Add the duplicate TSN information.  */
843 	if (num_dup_tsns) {
844 		asoc->stats.idupchunks += num_dup_tsns;
845 		sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns,
846 				 sctp_tsnmap_get_dups(map));
847 	}
848 	/* Once we have a sack generated, check to see what our sack
849 	 * generation is, if its 0, reset the transports to 0, and reset
850 	 * the association generation to 1
851 	 *
852 	 * The idea is that zero is never used as a valid generation for the
853 	 * association so no transport will match after a wrap event like this,
854 	 * Until the next sack
855 	 */
856 	if (++asoc->peer.sack_generation == 0) {
857 		list_for_each_entry(trans, &asoc->peer.transport_addr_list,
858 				    transports)
859 			trans->sack_generation = 0;
860 		asoc->peer.sack_generation = 1;
861 	}
862 nodata:
863 	return retval;
864 }
865 
866 /* Make a SHUTDOWN chunk. */
867 struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
868 				      const struct sctp_chunk *chunk)
869 {
870 	struct sctp_shutdownhdr shut;
871 	struct sctp_chunk *retval;
872 	__u32 ctsn;
873 
874 	ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
875 	shut.cum_tsn_ack = htonl(ctsn);
876 
877 	retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN, 0,
878 				   sizeof(shut), GFP_ATOMIC);
879 	if (!retval)
880 		goto nodata;
881 
882 	retval->subh.shutdown_hdr =
883 		sctp_addto_chunk(retval, sizeof(shut), &shut);
884 
885 	if (chunk)
886 		retval->transport = chunk->transport;
887 nodata:
888 	return retval;
889 }
890 
891 struct sctp_chunk *sctp_make_shutdown_ack(const struct sctp_association *asoc,
892 					  const struct sctp_chunk *chunk)
893 {
894 	struct sctp_chunk *retval;
895 
896 	retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_ACK, 0, 0,
897 				   GFP_ATOMIC);
898 
899 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
900 	 *
901 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
902 	 * HEARTBEAT ACK, * etc.) to the same destination transport
903 	 * address from which it * received the DATA or control chunk
904 	 * to which it is replying.
905 	 *
906 	 * [ACK back to where the SHUTDOWN came from.]
907 	 */
908 	if (retval && chunk)
909 		retval->transport = chunk->transport;
910 
911 	return retval;
912 }
913 
914 struct sctp_chunk *sctp_make_shutdown_complete(
915 					const struct sctp_association *asoc,
916 					const struct sctp_chunk *chunk)
917 {
918 	struct sctp_chunk *retval;
919 	__u8 flags = 0;
920 
921 	/* Set the T-bit if we have no association (vtag will be
922 	 * reflected)
923 	 */
924 	flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;
925 
926 	retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags,
927 				   0, GFP_ATOMIC);
928 
929 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
930 	 *
931 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
932 	 * HEARTBEAT ACK, * etc.) to the same destination transport
933 	 * address from which it * received the DATA or control chunk
934 	 * to which it is replying.
935 	 *
936 	 * [Report SHUTDOWN COMPLETE back to where the SHUTDOWN ACK
937 	 * came from.]
938 	 */
939 	if (retval && chunk)
940 		retval->transport = chunk->transport;
941 
942 	return retval;
943 }
944 
945 /* Create an ABORT.  Note that we set the T bit if we have no
946  * association, except when responding to an INIT (sctpimpguide 2.41).
947  */
948 struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc,
949 				   const struct sctp_chunk *chunk,
950 				   const size_t hint)
951 {
952 	struct sctp_chunk *retval;
953 	__u8 flags = 0;
954 
955 	/* Set the T-bit if we have no association and 'chunk' is not
956 	 * an INIT (vtag will be reflected).
957 	 */
958 	if (!asoc) {
959 		if (chunk && chunk->chunk_hdr &&
960 		    chunk->chunk_hdr->type == SCTP_CID_INIT)
961 			flags = 0;
962 		else
963 			flags = SCTP_CHUNK_FLAG_T;
964 	}
965 
966 	retval = sctp_make_control(asoc, SCTP_CID_ABORT, flags, hint,
967 				   GFP_ATOMIC);
968 
969 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
970 	 *
971 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
972 	 * HEARTBEAT ACK, * etc.) to the same destination transport
973 	 * address from which it * received the DATA or control chunk
974 	 * to which it is replying.
975 	 *
976 	 * [ABORT back to where the offender came from.]
977 	 */
978 	if (retval && chunk)
979 		retval->transport = chunk->transport;
980 
981 	return retval;
982 }
983 
984 /* Helper to create ABORT with a NO_USER_DATA error.  */
985 struct sctp_chunk *sctp_make_abort_no_data(
986 					const struct sctp_association *asoc,
987 					const struct sctp_chunk *chunk,
988 					__u32 tsn)
989 {
990 	struct sctp_chunk *retval;
991 	__be32 payload;
992 
993 	retval = sctp_make_abort(asoc, chunk,
994 				 sizeof(struct sctp_errhdr) + sizeof(tsn));
995 
996 	if (!retval)
997 		goto no_mem;
998 
999 	/* Put the tsn back into network byte order.  */
1000 	payload = htonl(tsn);
1001 	sctp_init_cause(retval, SCTP_ERROR_NO_DATA, sizeof(payload));
1002 	sctp_addto_chunk(retval, sizeof(payload), (const void *)&payload);
1003 
1004 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
1005 	 *
1006 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1007 	 * HEARTBEAT ACK, * etc.) to the same destination transport
1008 	 * address from which it * received the DATA or control chunk
1009 	 * to which it is replying.
1010 	 *
1011 	 * [ABORT back to where the offender came from.]
1012 	 */
1013 	if (chunk)
1014 		retval->transport = chunk->transport;
1015 
1016 no_mem:
1017 	return retval;
1018 }
1019 
1020 /* Helper to create ABORT with a SCTP_ERROR_USER_ABORT error.  */
1021 struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *asoc,
1022 					struct msghdr *msg,
1023 					size_t paylen)
1024 {
1025 	struct sctp_chunk *retval;
1026 	void *payload = NULL;
1027 	int err;
1028 
1029 	retval = sctp_make_abort(asoc, NULL,
1030 				 sizeof(struct sctp_errhdr) + paylen);
1031 	if (!retval)
1032 		goto err_chunk;
1033 
1034 	if (paylen) {
1035 		/* Put the msg_iov together into payload.  */
1036 		payload = kmalloc(paylen, GFP_KERNEL);
1037 		if (!payload)
1038 			goto err_payload;
1039 
1040 		err = memcpy_from_msg(payload, msg, paylen);
1041 		if (err < 0)
1042 			goto err_copy;
1043 	}
1044 
1045 	sctp_init_cause(retval, SCTP_ERROR_USER_ABORT, paylen);
1046 	sctp_addto_chunk(retval, paylen, payload);
1047 
1048 	if (paylen)
1049 		kfree(payload);
1050 
1051 	return retval;
1052 
1053 err_copy:
1054 	kfree(payload);
1055 err_payload:
1056 	sctp_chunk_free(retval);
1057 	retval = NULL;
1058 err_chunk:
1059 	return retval;
1060 }
1061 
1062 /* Append bytes to the end of a parameter.  Will panic if chunk is not big
1063  * enough.
1064  */
1065 static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
1066 			      const void *data)
1067 {
1068 	int chunklen = ntohs(chunk->chunk_hdr->length);
1069 	void *target;
1070 
1071 	target = skb_put(chunk->skb, len);
1072 
1073 	if (data)
1074 		memcpy(target, data, len);
1075 	else
1076 		memset(target, 0, len);
1077 
1078 	/* Adjust the chunk length field.  */
1079 	chunk->chunk_hdr->length = htons(chunklen + len);
1080 	chunk->chunk_end = skb_tail_pointer(chunk->skb);
1081 
1082 	return target;
1083 }
1084 
1085 /* Make an ABORT chunk with a PROTOCOL VIOLATION cause code. */
1086 struct sctp_chunk *sctp_make_abort_violation(
1087 					const struct sctp_association *asoc,
1088 					const struct sctp_chunk *chunk,
1089 					const __u8 *payload,
1090 					const size_t paylen)
1091 {
1092 	struct sctp_chunk  *retval;
1093 	struct sctp_paramhdr phdr;
1094 
1095 	retval = sctp_make_abort(asoc, chunk, sizeof(struct sctp_errhdr) +
1096 					      paylen + sizeof(phdr));
1097 	if (!retval)
1098 		goto end;
1099 
1100 	sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, paylen +
1101 							    sizeof(phdr));
1102 
1103 	phdr.type = htons(chunk->chunk_hdr->type);
1104 	phdr.length = chunk->chunk_hdr->length;
1105 	sctp_addto_chunk(retval, paylen, payload);
1106 	sctp_addto_param(retval, sizeof(phdr), &phdr);
1107 
1108 end:
1109 	return retval;
1110 }
1111 
1112 struct sctp_chunk *sctp_make_violation_paramlen(
1113 					const struct sctp_association *asoc,
1114 					const struct sctp_chunk *chunk,
1115 					struct sctp_paramhdr *param)
1116 {
1117 	static const char error[] = "The following parameter had invalid length:";
1118 	size_t payload_len = sizeof(error) + sizeof(struct sctp_errhdr) +
1119 			     sizeof(*param);
1120 	struct sctp_chunk *retval;
1121 
1122 	retval = sctp_make_abort(asoc, chunk, payload_len);
1123 	if (!retval)
1124 		goto nodata;
1125 
1126 	sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION,
1127 			sizeof(error) + sizeof(*param));
1128 	sctp_addto_chunk(retval, sizeof(error), error);
1129 	sctp_addto_param(retval, sizeof(*param), param);
1130 
1131 nodata:
1132 	return retval;
1133 }
1134 
1135 struct sctp_chunk *sctp_make_violation_max_retrans(
1136 					const struct sctp_association *asoc,
1137 					const struct sctp_chunk *chunk)
1138 {
1139 	static const char error[] = "Association exceeded its max_retrans count";
1140 	size_t payload_len = sizeof(error) + sizeof(struct sctp_errhdr);
1141 	struct sctp_chunk *retval;
1142 
1143 	retval = sctp_make_abort(asoc, chunk, payload_len);
1144 	if (!retval)
1145 		goto nodata;
1146 
1147 	sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, sizeof(error));
1148 	sctp_addto_chunk(retval, sizeof(error), error);
1149 
1150 nodata:
1151 	return retval;
1152 }
1153 
1154 /* Make a HEARTBEAT chunk.  */
1155 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
1156 				       const struct sctp_transport *transport)
1157 {
1158 	struct sctp_sender_hb_info hbinfo;
1159 	struct sctp_chunk *retval;
1160 
1161 	retval = sctp_make_control(asoc, SCTP_CID_HEARTBEAT, 0,
1162 				   sizeof(hbinfo), GFP_ATOMIC);
1163 
1164 	if (!retval)
1165 		goto nodata;
1166 
1167 	hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO;
1168 	hbinfo.param_hdr.length = htons(sizeof(hbinfo));
1169 	hbinfo.daddr = transport->ipaddr;
1170 	hbinfo.sent_at = jiffies;
1171 	hbinfo.hb_nonce = transport->hb_nonce;
1172 
1173 	/* Cast away the 'const', as this is just telling the chunk
1174 	 * what transport it belongs to.
1175 	 */
1176 	retval->transport = (struct sctp_transport *) transport;
1177 	retval->subh.hbs_hdr = sctp_addto_chunk(retval, sizeof(hbinfo),
1178 						&hbinfo);
1179 
1180 nodata:
1181 	return retval;
1182 }
1183 
1184 struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc,
1185 					   const struct sctp_chunk *chunk,
1186 					   const void *payload,
1187 					   const size_t paylen)
1188 {
1189 	struct sctp_chunk *retval;
1190 
1191 	retval  = sctp_make_control(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen,
1192 				    GFP_ATOMIC);
1193 	if (!retval)
1194 		goto nodata;
1195 
1196 	retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);
1197 
1198 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
1199 	 *
1200 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1201 	 * HEARTBEAT ACK, * etc.) to the same destination transport
1202 	 * address from which it * received the DATA or control chunk
1203 	 * to which it is replying.
1204 	 *
1205 	 * [HBACK back to where the HEARTBEAT came from.]
1206 	 */
1207 	if (chunk)
1208 		retval->transport = chunk->transport;
1209 
1210 nodata:
1211 	return retval;
1212 }
1213 
1214 /* Create an Operation Error chunk with the specified space reserved.
1215  * This routine can be used for containing multiple causes in the chunk.
1216  */
1217 static struct sctp_chunk *sctp_make_op_error_space(
1218 					const struct sctp_association *asoc,
1219 					const struct sctp_chunk *chunk,
1220 					size_t size)
1221 {
1222 	struct sctp_chunk *retval;
1223 
1224 	retval = sctp_make_control(asoc, SCTP_CID_ERROR, 0,
1225 				   sizeof(struct sctp_errhdr) + size,
1226 				   GFP_ATOMIC);
1227 	if (!retval)
1228 		goto nodata;
1229 
1230 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
1231 	 *
1232 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1233 	 * HEARTBEAT ACK, etc.) to the same destination transport
1234 	 * address from which it received the DATA or control chunk
1235 	 * to which it is replying.
1236 	 *
1237 	 */
1238 	if (chunk)
1239 		retval->transport = chunk->transport;
1240 
1241 nodata:
1242 	return retval;
1243 }
1244 
1245 /* Create an Operation Error chunk of a fixed size, specifically,
1246  * min(asoc->pathmtu, SCTP_DEFAULT_MAXSEGMENT) - overheads.
1247  * This is a helper function to allocate an error chunk for for those
1248  * invalid parameter codes in which we may not want to report all the
1249  * errors, if the incoming chunk is large. If it can't fit in a single
1250  * packet, we ignore it.
1251  */
1252 static inline struct sctp_chunk *sctp_make_op_error_limited(
1253 					const struct sctp_association *asoc,
1254 					const struct sctp_chunk *chunk)
1255 {
1256 	size_t size = SCTP_DEFAULT_MAXSEGMENT;
1257 	struct sctp_sock *sp = NULL;
1258 
1259 	if (asoc) {
1260 		size = min_t(size_t, size, asoc->pathmtu);
1261 		sp = sctp_sk(asoc->base.sk);
1262 	}
1263 
1264 	size = sctp_mtu_payload(sp, size, sizeof(struct sctp_errhdr));
1265 
1266 	return sctp_make_op_error_space(asoc, chunk, size);
1267 }
1268 
1269 /* Create an Operation Error chunk.  */
1270 struct sctp_chunk *sctp_make_op_error(const struct sctp_association *asoc,
1271 				      const struct sctp_chunk *chunk,
1272 				      __be16 cause_code, const void *payload,
1273 				      size_t paylen, size_t reserve_tail)
1274 {
1275 	struct sctp_chunk *retval;
1276 
1277 	retval = sctp_make_op_error_space(asoc, chunk, paylen + reserve_tail);
1278 	if (!retval)
1279 		goto nodata;
1280 
1281 	sctp_init_cause(retval, cause_code, paylen + reserve_tail);
1282 	sctp_addto_chunk(retval, paylen, payload);
1283 	if (reserve_tail)
1284 		sctp_addto_param(retval, reserve_tail, NULL);
1285 
1286 nodata:
1287 	return retval;
1288 }
1289 
1290 struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc,
1291 				  __u16 key_id)
1292 {
1293 	struct sctp_authhdr auth_hdr;
1294 	struct sctp_hmac *hmac_desc;
1295 	struct sctp_chunk *retval;
1296 
1297 	/* Get the first hmac that the peer told us to use */
1298 	hmac_desc = sctp_auth_asoc_get_hmac(asoc);
1299 	if (unlikely(!hmac_desc))
1300 		return NULL;
1301 
1302 	retval = sctp_make_control(asoc, SCTP_CID_AUTH, 0,
1303 				   hmac_desc->hmac_len + sizeof(auth_hdr),
1304 				   GFP_ATOMIC);
1305 	if (!retval)
1306 		return NULL;
1307 
1308 	auth_hdr.hmac_id = htons(hmac_desc->hmac_id);
1309 	auth_hdr.shkey_id = htons(key_id);
1310 
1311 	retval->subh.auth_hdr = sctp_addto_chunk(retval, sizeof(auth_hdr),
1312 						 &auth_hdr);
1313 
1314 	skb_put_zero(retval->skb, hmac_desc->hmac_len);
1315 
1316 	/* Adjust the chunk header to include the empty MAC */
1317 	retval->chunk_hdr->length =
1318 		htons(ntohs(retval->chunk_hdr->length) + hmac_desc->hmac_len);
1319 	retval->chunk_end = skb_tail_pointer(retval->skb);
1320 
1321 	return retval;
1322 }
1323 
1324 
1325 /********************************************************************
1326  * 2nd Level Abstractions
1327  ********************************************************************/
1328 
1329 /* Turn an skb into a chunk.
1330  * FIXME: Eventually move the structure directly inside the skb->cb[].
1331  *
1332  * sctpimpguide-05.txt Section 2.8.2
1333  * M1) Each time a new DATA chunk is transmitted
1334  * set the 'TSN.Missing.Report' count for that TSN to 0. The
1335  * 'TSN.Missing.Report' count will be used to determine missing chunks
1336  * and when to fast retransmit.
1337  *
1338  */
1339 struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
1340 				 const struct sctp_association *asoc,
1341 				 struct sock *sk, gfp_t gfp)
1342 {
1343 	struct sctp_chunk *retval;
1344 
1345 	retval = kmem_cache_zalloc(sctp_chunk_cachep, gfp);
1346 
1347 	if (!retval)
1348 		goto nodata;
1349 	if (!sk)
1350 		pr_debug("%s: chunkifying skb:%p w/o an sk\n", __func__, skb);
1351 
1352 	INIT_LIST_HEAD(&retval->list);
1353 	retval->skb		= skb;
1354 	retval->asoc		= (struct sctp_association *)asoc;
1355 	retval->singleton	= 1;
1356 
1357 	retval->fast_retransmit = SCTP_CAN_FRTX;
1358 
1359 	/* Polish the bead hole.  */
1360 	INIT_LIST_HEAD(&retval->transmitted_list);
1361 	INIT_LIST_HEAD(&retval->frag_list);
1362 	SCTP_DBG_OBJCNT_INC(chunk);
1363 	refcount_set(&retval->refcnt, 1);
1364 
1365 nodata:
1366 	return retval;
1367 }
1368 
1369 /* Set chunk->source and dest based on the IP header in chunk->skb.  */
1370 void sctp_init_addrs(struct sctp_chunk *chunk, union sctp_addr *src,
1371 		     union sctp_addr *dest)
1372 {
1373 	memcpy(&chunk->source, src, sizeof(union sctp_addr));
1374 	memcpy(&chunk->dest, dest, sizeof(union sctp_addr));
1375 }
1376 
1377 /* Extract the source address from a chunk.  */
1378 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk)
1379 {
1380 	/* If we have a known transport, use that.  */
1381 	if (chunk->transport) {
1382 		return &chunk->transport->ipaddr;
1383 	} else {
1384 		/* Otherwise, extract it from the IP header.  */
1385 		return &chunk->source;
1386 	}
1387 }
1388 
1389 /* Create a new chunk, setting the type and flags headers from the
1390  * arguments, reserving enough space for a 'paylen' byte payload.
1391  */
1392 static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc,
1393 					   __u8 type, __u8 flags, int paylen,
1394 					   gfp_t gfp)
1395 {
1396 	struct sctp_chunkhdr *chunk_hdr;
1397 	struct sctp_chunk *retval;
1398 	struct sk_buff *skb;
1399 	struct sock *sk;
1400 	int chunklen;
1401 
1402 	chunklen = SCTP_PAD4(sizeof(*chunk_hdr) + paylen);
1403 	if (chunklen > SCTP_MAX_CHUNK_LEN)
1404 		goto nodata;
1405 
1406 	/* No need to allocate LL here, as this is only a chunk. */
1407 	skb = alloc_skb(chunklen, gfp);
1408 	if (!skb)
1409 		goto nodata;
1410 
1411 	/* Make room for the chunk header.  */
1412 	chunk_hdr = (struct sctp_chunkhdr *)skb_put(skb, sizeof(*chunk_hdr));
1413 	chunk_hdr->type	  = type;
1414 	chunk_hdr->flags  = flags;
1415 	chunk_hdr->length = htons(sizeof(*chunk_hdr));
1416 
1417 	sk = asoc ? asoc->base.sk : NULL;
1418 	retval = sctp_chunkify(skb, asoc, sk, gfp);
1419 	if (!retval) {
1420 		kfree_skb(skb);
1421 		goto nodata;
1422 	}
1423 
1424 	retval->chunk_hdr = chunk_hdr;
1425 	retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(*chunk_hdr);
1426 
1427 	/* Determine if the chunk needs to be authenticated */
1428 	if (sctp_auth_send_cid(type, asoc))
1429 		retval->auth = 1;
1430 
1431 	return retval;
1432 nodata:
1433 	return NULL;
1434 }
1435 
1436 static struct sctp_chunk *sctp_make_data(const struct sctp_association *asoc,
1437 					 __u8 flags, int paylen, gfp_t gfp)
1438 {
1439 	return _sctp_make_chunk(asoc, SCTP_CID_DATA, flags, paylen, gfp);
1440 }
1441 
1442 struct sctp_chunk *sctp_make_idata(const struct sctp_association *asoc,
1443 				   __u8 flags, int paylen, gfp_t gfp)
1444 {
1445 	return _sctp_make_chunk(asoc, SCTP_CID_I_DATA, flags, paylen, gfp);
1446 }
1447 
1448 static struct sctp_chunk *sctp_make_control(const struct sctp_association *asoc,
1449 					    __u8 type, __u8 flags, int paylen,
1450 					    gfp_t gfp)
1451 {
1452 	struct sctp_chunk *chunk;
1453 
1454 	chunk = _sctp_make_chunk(asoc, type, flags, paylen, gfp);
1455 	if (chunk)
1456 		sctp_control_set_owner_w(chunk);
1457 
1458 	return chunk;
1459 }
1460 
1461 /* Release the memory occupied by a chunk.  */
1462 static void sctp_chunk_destroy(struct sctp_chunk *chunk)
1463 {
1464 	BUG_ON(!list_empty(&chunk->list));
1465 	list_del_init(&chunk->transmitted_list);
1466 
1467 	consume_skb(chunk->skb);
1468 	consume_skb(chunk->auth_chunk);
1469 
1470 	SCTP_DBG_OBJCNT_DEC(chunk);
1471 	kmem_cache_free(sctp_chunk_cachep, chunk);
1472 }
1473 
1474 /* Possibly, free the chunk.  */
1475 void sctp_chunk_free(struct sctp_chunk *chunk)
1476 {
1477 	/* Release our reference on the message tracker. */
1478 	if (chunk->msg)
1479 		sctp_datamsg_put(chunk->msg);
1480 
1481 	sctp_chunk_put(chunk);
1482 }
1483 
1484 /* Grab a reference to the chunk. */
1485 void sctp_chunk_hold(struct sctp_chunk *ch)
1486 {
1487 	refcount_inc(&ch->refcnt);
1488 }
1489 
1490 /* Release a reference to the chunk. */
1491 void sctp_chunk_put(struct sctp_chunk *ch)
1492 {
1493 	if (refcount_dec_and_test(&ch->refcnt))
1494 		sctp_chunk_destroy(ch);
1495 }
1496 
1497 /* Append bytes to the end of a chunk.  Will panic if chunk is not big
1498  * enough.
1499  */
1500 void *sctp_addto_chunk(struct sctp_chunk *chunk, int len, const void *data)
1501 {
1502 	int chunklen = ntohs(chunk->chunk_hdr->length);
1503 	int padlen = SCTP_PAD4(chunklen) - chunklen;
1504 	void *target;
1505 
1506 	skb_put_zero(chunk->skb, padlen);
1507 	target = skb_put_data(chunk->skb, data, len);
1508 
1509 	/* Adjust the chunk length field.  */
1510 	chunk->chunk_hdr->length = htons(chunklen + padlen + len);
1511 	chunk->chunk_end = skb_tail_pointer(chunk->skb);
1512 
1513 	return target;
1514 }
1515 
1516 /* Append bytes from user space to the end of a chunk.  Will panic if
1517  * chunk is not big enough.
1518  * Returns a kernel err value.
1519  */
1520 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
1521 			  struct iov_iter *from)
1522 {
1523 	void *target;
1524 
1525 	/* Make room in chunk for data.  */
1526 	target = skb_put(chunk->skb, len);
1527 
1528 	/* Copy data (whole iovec) into chunk */
1529 	if (!copy_from_iter_full(target, len, from))
1530 		return -EFAULT;
1531 
1532 	/* Adjust the chunk length field.  */
1533 	chunk->chunk_hdr->length =
1534 		htons(ntohs(chunk->chunk_hdr->length) + len);
1535 	chunk->chunk_end = skb_tail_pointer(chunk->skb);
1536 
1537 	return 0;
1538 }
1539 
1540 /* Helper function to assign a TSN if needed.  This assumes that both
1541  * the data_hdr and association have already been assigned.
1542  */
1543 void sctp_chunk_assign_ssn(struct sctp_chunk *chunk)
1544 {
1545 	struct sctp_stream *stream;
1546 	struct sctp_chunk *lchunk;
1547 	struct sctp_datamsg *msg;
1548 	__u16 ssn, sid;
1549 
1550 	if (chunk->has_ssn)
1551 		return;
1552 
1553 	/* All fragments will be on the same stream */
1554 	sid = ntohs(chunk->subh.data_hdr->stream);
1555 	stream = &chunk->asoc->stream;
1556 
1557 	/* Now assign the sequence number to the entire message.
1558 	 * All fragments must have the same stream sequence number.
1559 	 */
1560 	msg = chunk->msg;
1561 	list_for_each_entry(lchunk, &msg->chunks, frag_list) {
1562 		if (lchunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
1563 			ssn = 0;
1564 		} else {
1565 			if (lchunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG)
1566 				ssn = sctp_ssn_next(stream, out, sid);
1567 			else
1568 				ssn = sctp_ssn_peek(stream, out, sid);
1569 		}
1570 
1571 		lchunk->subh.data_hdr->ssn = htons(ssn);
1572 		lchunk->has_ssn = 1;
1573 	}
1574 }
1575 
1576 /* Helper function to assign a TSN if needed.  This assumes that both
1577  * the data_hdr and association have already been assigned.
1578  */
1579 void sctp_chunk_assign_tsn(struct sctp_chunk *chunk)
1580 {
1581 	if (!chunk->has_tsn) {
1582 		/* This is the last possible instant to
1583 		 * assign a TSN.
1584 		 */
1585 		chunk->subh.data_hdr->tsn =
1586 			htonl(sctp_association_get_next_tsn(chunk->asoc));
1587 		chunk->has_tsn = 1;
1588 	}
1589 }
1590 
1591 /* Create a CLOSED association to use with an incoming packet.  */
1592 struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *ep,
1593 					     struct sctp_chunk *chunk,
1594 					     gfp_t gfp)
1595 {
1596 	struct sctp_association *asoc;
1597 	enum sctp_scope scope;
1598 	struct sk_buff *skb;
1599 
1600 	/* Create the bare association.  */
1601 	scope = sctp_scope(sctp_source(chunk));
1602 	asoc = sctp_association_new(ep, ep->base.sk, scope, gfp);
1603 	if (!asoc)
1604 		goto nodata;
1605 	asoc->temp = 1;
1606 	skb = chunk->skb;
1607 	/* Create an entry for the source address of the packet.  */
1608 	SCTP_INPUT_CB(skb)->af->from_skb(&asoc->c.peer_addr, skb, 1);
1609 
1610 nodata:
1611 	return asoc;
1612 }
1613 
1614 /* Build a cookie representing asoc.
1615  * This INCLUDES the param header needed to put the cookie in the INIT ACK.
1616  */
1617 static struct sctp_cookie_param *sctp_pack_cookie(
1618 					const struct sctp_endpoint *ep,
1619 					const struct sctp_association *asoc,
1620 					const struct sctp_chunk *init_chunk,
1621 					int *cookie_len, const __u8 *raw_addrs,
1622 					int addrs_len)
1623 {
1624 	struct sctp_signed_cookie *cookie;
1625 	struct sctp_cookie_param *retval;
1626 	int headersize, bodysize;
1627 
1628 	/* Header size is static data prior to the actual cookie, including
1629 	 * any padding.
1630 	 */
1631 	headersize = sizeof(struct sctp_paramhdr) +
1632 		     (sizeof(struct sctp_signed_cookie) -
1633 		      sizeof(struct sctp_cookie));
1634 	bodysize = sizeof(struct sctp_cookie)
1635 		+ ntohs(init_chunk->chunk_hdr->length) + addrs_len;
1636 
1637 	/* Pad out the cookie to a multiple to make the signature
1638 	 * functions simpler to write.
1639 	 */
1640 	if (bodysize % SCTP_COOKIE_MULTIPLE)
1641 		bodysize += SCTP_COOKIE_MULTIPLE
1642 			- (bodysize % SCTP_COOKIE_MULTIPLE);
1643 	*cookie_len = headersize + bodysize;
1644 
1645 	/* Clear this memory since we are sending this data structure
1646 	 * out on the network.
1647 	 */
1648 	retval = kzalloc(*cookie_len, GFP_ATOMIC);
1649 	if (!retval)
1650 		goto nodata;
1651 
1652 	cookie = (struct sctp_signed_cookie *) retval->body;
1653 
1654 	/* Set up the parameter header.  */
1655 	retval->p.type = SCTP_PARAM_STATE_COOKIE;
1656 	retval->p.length = htons(*cookie_len);
1657 
1658 	/* Copy the cookie part of the association itself.  */
1659 	cookie->c = asoc->c;
1660 	/* Save the raw address list length in the cookie. */
1661 	cookie->c.raw_addr_list_len = addrs_len;
1662 
1663 	/* Remember PR-SCTP capability. */
1664 	cookie->c.prsctp_capable = asoc->peer.prsctp_capable;
1665 
1666 	/* Save adaptation indication in the cookie. */
1667 	cookie->c.adaptation_ind = asoc->peer.adaptation_ind;
1668 
1669 	/* Set an expiration time for the cookie.  */
1670 	cookie->c.expiration = ktime_add(asoc->cookie_life,
1671 					 ktime_get_real());
1672 
1673 	/* Copy the peer's init packet.  */
1674 	memcpy(&cookie->c.peer_init[0], init_chunk->chunk_hdr,
1675 	       ntohs(init_chunk->chunk_hdr->length));
1676 
1677 	/* Copy the raw local address list of the association. */
1678 	memcpy((__u8 *)&cookie->c.peer_init[0] +
1679 	       ntohs(init_chunk->chunk_hdr->length), raw_addrs, addrs_len);
1680 
1681 	if (sctp_sk(ep->base.sk)->hmac) {
1682 		SHASH_DESC_ON_STACK(desc, sctp_sk(ep->base.sk)->hmac);
1683 		int err;
1684 
1685 		/* Sign the message.  */
1686 		desc->tfm = sctp_sk(ep->base.sk)->hmac;
1687 		desc->flags = 0;
1688 
1689 		err = crypto_shash_setkey(desc->tfm, ep->secret_key,
1690 					  sizeof(ep->secret_key)) ?:
1691 		      crypto_shash_digest(desc, (u8 *)&cookie->c, bodysize,
1692 					  cookie->signature);
1693 		shash_desc_zero(desc);
1694 		if (err)
1695 			goto free_cookie;
1696 	}
1697 
1698 	return retval;
1699 
1700 free_cookie:
1701 	kfree(retval);
1702 nodata:
1703 	*cookie_len = 0;
1704 	return NULL;
1705 }
1706 
1707 /* Unpack the cookie from COOKIE ECHO chunk, recreating the association.  */
1708 struct sctp_association *sctp_unpack_cookie(
1709 					const struct sctp_endpoint *ep,
1710 					const struct sctp_association *asoc,
1711 					struct sctp_chunk *chunk, gfp_t gfp,
1712 					int *error, struct sctp_chunk **errp)
1713 {
1714 	struct sctp_association *retval = NULL;
1715 	int headersize, bodysize, fixed_size;
1716 	struct sctp_signed_cookie *cookie;
1717 	struct sk_buff *skb = chunk->skb;
1718 	struct sctp_cookie *bear_cookie;
1719 	__u8 *digest = ep->digest;
1720 	enum sctp_scope scope;
1721 	unsigned int len;
1722 	ktime_t kt;
1723 
1724 	/* Header size is static data prior to the actual cookie, including
1725 	 * any padding.
1726 	 */
1727 	headersize = sizeof(struct sctp_chunkhdr) +
1728 		     (sizeof(struct sctp_signed_cookie) -
1729 		      sizeof(struct sctp_cookie));
1730 	bodysize = ntohs(chunk->chunk_hdr->length) - headersize;
1731 	fixed_size = headersize + sizeof(struct sctp_cookie);
1732 
1733 	/* Verify that the chunk looks like it even has a cookie.
1734 	 * There must be enough room for our cookie and our peer's
1735 	 * INIT chunk.
1736 	 */
1737 	len = ntohs(chunk->chunk_hdr->length);
1738 	if (len < fixed_size + sizeof(struct sctp_chunkhdr))
1739 		goto malformed;
1740 
1741 	/* Verify that the cookie has been padded out. */
1742 	if (bodysize % SCTP_COOKIE_MULTIPLE)
1743 		goto malformed;
1744 
1745 	/* Process the cookie.  */
1746 	cookie = chunk->subh.cookie_hdr;
1747 	bear_cookie = &cookie->c;
1748 
1749 	if (!sctp_sk(ep->base.sk)->hmac)
1750 		goto no_hmac;
1751 
1752 	/* Check the signature.  */
1753 	{
1754 		SHASH_DESC_ON_STACK(desc, sctp_sk(ep->base.sk)->hmac);
1755 		int err;
1756 
1757 		desc->tfm = sctp_sk(ep->base.sk)->hmac;
1758 		desc->flags = 0;
1759 
1760 		err = crypto_shash_setkey(desc->tfm, ep->secret_key,
1761 					  sizeof(ep->secret_key)) ?:
1762 		      crypto_shash_digest(desc, (u8 *)bear_cookie, bodysize,
1763 					  digest);
1764 		shash_desc_zero(desc);
1765 
1766 		if (err) {
1767 			*error = -SCTP_IERROR_NOMEM;
1768 			goto fail;
1769 		}
1770 	}
1771 
1772 	if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
1773 		*error = -SCTP_IERROR_BAD_SIG;
1774 		goto fail;
1775 	}
1776 
1777 no_hmac:
1778 	/* IG Section 2.35.2:
1779 	 *  3) Compare the port numbers and the verification tag contained
1780 	 *     within the COOKIE ECHO chunk to the actual port numbers and the
1781 	 *     verification tag within the SCTP common header of the received
1782 	 *     packet. If these values do not match the packet MUST be silently
1783 	 *     discarded,
1784 	 */
1785 	if (ntohl(chunk->sctp_hdr->vtag) != bear_cookie->my_vtag) {
1786 		*error = -SCTP_IERROR_BAD_TAG;
1787 		goto fail;
1788 	}
1789 
1790 	if (chunk->sctp_hdr->source != bear_cookie->peer_addr.v4.sin_port ||
1791 	    ntohs(chunk->sctp_hdr->dest) != bear_cookie->my_port) {
1792 		*error = -SCTP_IERROR_BAD_PORTS;
1793 		goto fail;
1794 	}
1795 
1796 	/* Check to see if the cookie is stale.  If there is already
1797 	 * an association, there is no need to check cookie's expiration
1798 	 * for init collision case of lost COOKIE ACK.
1799 	 * If skb has been timestamped, then use the stamp, otherwise
1800 	 * use current time.  This introduces a small possibility that
1801 	 * that a cookie may be considered expired, but his would only slow
1802 	 * down the new association establishment instead of every packet.
1803 	 */
1804 	if (sock_flag(ep->base.sk, SOCK_TIMESTAMP))
1805 		kt = skb_get_ktime(skb);
1806 	else
1807 		kt = ktime_get_real();
1808 
1809 	if (!asoc && ktime_before(bear_cookie->expiration, kt)) {
1810 		suseconds_t usecs = ktime_to_us(ktime_sub(kt, bear_cookie->expiration));
1811 		__be32 n = htonl(usecs);
1812 
1813 		/*
1814 		 * Section 3.3.10.3 Stale Cookie Error (3)
1815 		 *
1816 		 * Cause of error
1817 		 * ---------------
1818 		 * Stale Cookie Error:  Indicates the receipt of a valid State
1819 		 * Cookie that has expired.
1820 		 */
1821 		*errp = sctp_make_op_error(asoc, chunk,
1822 					   SCTP_ERROR_STALE_COOKIE, &n,
1823 					   sizeof(n), 0);
1824 		if (*errp)
1825 			*error = -SCTP_IERROR_STALE_COOKIE;
1826 		else
1827 			*error = -SCTP_IERROR_NOMEM;
1828 
1829 		goto fail;
1830 	}
1831 
1832 	/* Make a new base association.  */
1833 	scope = sctp_scope(sctp_source(chunk));
1834 	retval = sctp_association_new(ep, ep->base.sk, scope, gfp);
1835 	if (!retval) {
1836 		*error = -SCTP_IERROR_NOMEM;
1837 		goto fail;
1838 	}
1839 
1840 	/* Set up our peer's port number.  */
1841 	retval->peer.port = ntohs(chunk->sctp_hdr->source);
1842 
1843 	/* Populate the association from the cookie.  */
1844 	memcpy(&retval->c, bear_cookie, sizeof(*bear_cookie));
1845 
1846 	if (sctp_assoc_set_bind_addr_from_cookie(retval, bear_cookie,
1847 						 GFP_ATOMIC) < 0) {
1848 		*error = -SCTP_IERROR_NOMEM;
1849 		goto fail;
1850 	}
1851 
1852 	/* Also, add the destination address. */
1853 	if (list_empty(&retval->base.bind_addr.address_list)) {
1854 		sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest,
1855 				   sizeof(chunk->dest), SCTP_ADDR_SRC,
1856 				   GFP_ATOMIC);
1857 	}
1858 
1859 	retval->next_tsn = retval->c.initial_tsn;
1860 	retval->ctsn_ack_point = retval->next_tsn - 1;
1861 	retval->addip_serial = retval->c.initial_tsn;
1862 	retval->strreset_outseq = retval->c.initial_tsn;
1863 	retval->adv_peer_ack_point = retval->ctsn_ack_point;
1864 	retval->peer.prsctp_capable = retval->c.prsctp_capable;
1865 	retval->peer.adaptation_ind = retval->c.adaptation_ind;
1866 
1867 	/* The INIT stuff will be done by the side effects.  */
1868 	return retval;
1869 
1870 fail:
1871 	if (retval)
1872 		sctp_association_free(retval);
1873 
1874 	return NULL;
1875 
1876 malformed:
1877 	/* Yikes!  The packet is either corrupt or deliberately
1878 	 * malformed.
1879 	 */
1880 	*error = -SCTP_IERROR_MALFORMED;
1881 	goto fail;
1882 }
1883 
1884 /********************************************************************
1885  * 3rd Level Abstractions
1886  ********************************************************************/
1887 
1888 struct __sctp_missing {
1889 	__be32 num_missing;
1890 	__be16 type;
1891 }  __packed;
1892 
1893 /*
1894  * Report a missing mandatory parameter.
1895  */
1896 static int sctp_process_missing_param(const struct sctp_association *asoc,
1897 				      enum sctp_param paramtype,
1898 				      struct sctp_chunk *chunk,
1899 				      struct sctp_chunk **errp)
1900 {
1901 	struct __sctp_missing report;
1902 	__u16 len;
1903 
1904 	len = SCTP_PAD4(sizeof(report));
1905 
1906 	/* Make an ERROR chunk, preparing enough room for
1907 	 * returning multiple unknown parameters.
1908 	 */
1909 	if (!*errp)
1910 		*errp = sctp_make_op_error_space(asoc, chunk, len);
1911 
1912 	if (*errp) {
1913 		report.num_missing = htonl(1);
1914 		report.type = paramtype;
1915 		sctp_init_cause(*errp, SCTP_ERROR_MISS_PARAM,
1916 				sizeof(report));
1917 		sctp_addto_chunk(*errp, sizeof(report), &report);
1918 	}
1919 
1920 	/* Stop processing this chunk. */
1921 	return 0;
1922 }
1923 
1924 /* Report an Invalid Mandatory Parameter.  */
1925 static int sctp_process_inv_mandatory(const struct sctp_association *asoc,
1926 				      struct sctp_chunk *chunk,
1927 				      struct sctp_chunk **errp)
1928 {
1929 	/* Invalid Mandatory Parameter Error has no payload. */
1930 
1931 	if (!*errp)
1932 		*errp = sctp_make_op_error_space(asoc, chunk, 0);
1933 
1934 	if (*errp)
1935 		sctp_init_cause(*errp, SCTP_ERROR_INV_PARAM, 0);
1936 
1937 	/* Stop processing this chunk. */
1938 	return 0;
1939 }
1940 
1941 static int sctp_process_inv_paramlength(const struct sctp_association *asoc,
1942 					struct sctp_paramhdr *param,
1943 					const struct sctp_chunk *chunk,
1944 					struct sctp_chunk **errp)
1945 {
1946 	/* This is a fatal error.  Any accumulated non-fatal errors are
1947 	 * not reported.
1948 	 */
1949 	if (*errp)
1950 		sctp_chunk_free(*errp);
1951 
1952 	/* Create an error chunk and fill it in with our payload. */
1953 	*errp = sctp_make_violation_paramlen(asoc, chunk, param);
1954 
1955 	return 0;
1956 }
1957 
1958 
1959 /* Do not attempt to handle the HOST_NAME parm.  However, do
1960  * send back an indicator to the peer.
1961  */
1962 static int sctp_process_hn_param(const struct sctp_association *asoc,
1963 				 union sctp_params param,
1964 				 struct sctp_chunk *chunk,
1965 				 struct sctp_chunk **errp)
1966 {
1967 	__u16 len = ntohs(param.p->length);
1968 
1969 	/* Processing of the HOST_NAME parameter will generate an
1970 	 * ABORT.  If we've accumulated any non-fatal errors, they
1971 	 * would be unrecognized parameters and we should not include
1972 	 * them in the ABORT.
1973 	 */
1974 	if (*errp)
1975 		sctp_chunk_free(*errp);
1976 
1977 	*errp = sctp_make_op_error(asoc, chunk, SCTP_ERROR_DNS_FAILED,
1978 				   param.v, len, 0);
1979 
1980 	/* Stop processing this chunk. */
1981 	return 0;
1982 }
1983 
1984 static int sctp_verify_ext_param(struct net *net, union sctp_params param)
1985 {
1986 	__u16 num_ext = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
1987 	int have_asconf = 0;
1988 	int have_auth = 0;
1989 	int i;
1990 
1991 	for (i = 0; i < num_ext; i++) {
1992 		switch (param.ext->chunks[i]) {
1993 		case SCTP_CID_AUTH:
1994 			have_auth = 1;
1995 			break;
1996 		case SCTP_CID_ASCONF:
1997 		case SCTP_CID_ASCONF_ACK:
1998 			have_asconf = 1;
1999 			break;
2000 		}
2001 	}
2002 
2003 	/* ADD-IP Security: The draft requires us to ABORT or ignore the
2004 	 * INIT/INIT-ACK if ADD-IP is listed, but AUTH is not.  Do this
2005 	 * only if ADD-IP is turned on and we are not backward-compatible
2006 	 * mode.
2007 	 */
2008 	if (net->sctp.addip_noauth)
2009 		return 1;
2010 
2011 	if (net->sctp.addip_enable && !have_auth && have_asconf)
2012 		return 0;
2013 
2014 	return 1;
2015 }
2016 
2017 static void sctp_process_ext_param(struct sctp_association *asoc,
2018 				   union sctp_params param)
2019 {
2020 	__u16 num_ext = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
2021 	struct net *net = sock_net(asoc->base.sk);
2022 	int i;
2023 
2024 	for (i = 0; i < num_ext; i++) {
2025 		switch (param.ext->chunks[i]) {
2026 		case SCTP_CID_RECONF:
2027 			if (asoc->reconf_enable &&
2028 			    !asoc->peer.reconf_capable)
2029 				asoc->peer.reconf_capable = 1;
2030 			break;
2031 		case SCTP_CID_FWD_TSN:
2032 			if (asoc->prsctp_enable && !asoc->peer.prsctp_capable)
2033 				asoc->peer.prsctp_capable = 1;
2034 			break;
2035 		case SCTP_CID_AUTH:
2036 			/* if the peer reports AUTH, assume that he
2037 			 * supports AUTH.
2038 			 */
2039 			if (asoc->ep->auth_enable)
2040 				asoc->peer.auth_capable = 1;
2041 			break;
2042 		case SCTP_CID_ASCONF:
2043 		case SCTP_CID_ASCONF_ACK:
2044 			if (net->sctp.addip_enable)
2045 				asoc->peer.asconf_capable = 1;
2046 			break;
2047 		case SCTP_CID_I_DATA:
2048 			if (sctp_sk(asoc->base.sk)->strm_interleave)
2049 				asoc->intl_enable = 1;
2050 			break;
2051 		default:
2052 			break;
2053 		}
2054 	}
2055 }
2056 
2057 /* RFC 3.2.1 & the Implementers Guide 2.2.
2058  *
2059  * The Parameter Types are encoded such that the
2060  * highest-order two bits specify the action that must be
2061  * taken if the processing endpoint does not recognize the
2062  * Parameter Type.
2063  *
2064  * 00 - Stop processing this parameter; do not process any further
2065  * 	parameters within this chunk
2066  *
2067  * 01 - Stop processing this parameter, do not process any further
2068  *	parameters within this chunk, and report the unrecognized
2069  *	parameter in an 'Unrecognized Parameter' ERROR chunk.
2070  *
2071  * 10 - Skip this parameter and continue processing.
2072  *
2073  * 11 - Skip this parameter and continue processing but
2074  *	report the unrecognized parameter in an
2075  *	'Unrecognized Parameter' ERROR chunk.
2076  *
2077  * Return value:
2078  * 	SCTP_IERROR_NO_ERROR - continue with the chunk
2079  * 	SCTP_IERROR_ERROR    - stop and report an error.
2080  * 	SCTP_IERROR_NOMEME   - out of memory.
2081  */
2082 static enum sctp_ierror sctp_process_unk_param(
2083 					const struct sctp_association *asoc,
2084 					union sctp_params param,
2085 					struct sctp_chunk *chunk,
2086 					struct sctp_chunk **errp)
2087 {
2088 	int retval = SCTP_IERROR_NO_ERROR;
2089 
2090 	switch (param.p->type & SCTP_PARAM_ACTION_MASK) {
2091 	case SCTP_PARAM_ACTION_DISCARD:
2092 		retval =  SCTP_IERROR_ERROR;
2093 		break;
2094 	case SCTP_PARAM_ACTION_SKIP:
2095 		break;
2096 	case SCTP_PARAM_ACTION_DISCARD_ERR:
2097 		retval =  SCTP_IERROR_ERROR;
2098 		/* Fall through */
2099 	case SCTP_PARAM_ACTION_SKIP_ERR:
2100 		/* Make an ERROR chunk, preparing enough room for
2101 		 * returning multiple unknown parameters.
2102 		 */
2103 		if (!*errp) {
2104 			*errp = sctp_make_op_error_limited(asoc, chunk);
2105 			if (!*errp) {
2106 				/* If there is no memory for generating the
2107 				 * ERROR report as specified, an ABORT will be
2108 				 * triggered to the peer and the association
2109 				 * won't be established.
2110 				 */
2111 				retval = SCTP_IERROR_NOMEM;
2112 				break;
2113 			}
2114 		}
2115 
2116 		if (!sctp_init_cause(*errp, SCTP_ERROR_UNKNOWN_PARAM,
2117 				     ntohs(param.p->length)))
2118 			sctp_addto_chunk(*errp, ntohs(param.p->length),
2119 					 param.v);
2120 		break;
2121 	default:
2122 		break;
2123 	}
2124 
2125 	return retval;
2126 }
2127 
2128 /* Verify variable length parameters
2129  * Return values:
2130  * 	SCTP_IERROR_ABORT - trigger an ABORT
2131  * 	SCTP_IERROR_NOMEM - out of memory (abort)
2132  *	SCTP_IERROR_ERROR - stop processing, trigger an ERROR
2133  * 	SCTP_IERROR_NO_ERROR - continue with the chunk
2134  */
2135 static enum sctp_ierror sctp_verify_param(struct net *net,
2136 					  const struct sctp_endpoint *ep,
2137 					  const struct sctp_association *asoc,
2138 					  union sctp_params param,
2139 					  enum sctp_cid cid,
2140 					  struct sctp_chunk *chunk,
2141 					  struct sctp_chunk **err_chunk)
2142 {
2143 	struct sctp_hmac_algo_param *hmacs;
2144 	int retval = SCTP_IERROR_NO_ERROR;
2145 	__u16 n_elt, id = 0;
2146 	int i;
2147 
2148 	/* FIXME - This routine is not looking at each parameter per the
2149 	 * chunk type, i.e., unrecognized parameters should be further
2150 	 * identified based on the chunk id.
2151 	 */
2152 
2153 	switch (param.p->type) {
2154 	case SCTP_PARAM_IPV4_ADDRESS:
2155 	case SCTP_PARAM_IPV6_ADDRESS:
2156 	case SCTP_PARAM_COOKIE_PRESERVATIVE:
2157 	case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2158 	case SCTP_PARAM_STATE_COOKIE:
2159 	case SCTP_PARAM_HEARTBEAT_INFO:
2160 	case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2161 	case SCTP_PARAM_ECN_CAPABLE:
2162 	case SCTP_PARAM_ADAPTATION_LAYER_IND:
2163 		break;
2164 
2165 	case SCTP_PARAM_SUPPORTED_EXT:
2166 		if (!sctp_verify_ext_param(net, param))
2167 			return SCTP_IERROR_ABORT;
2168 		break;
2169 
2170 	case SCTP_PARAM_SET_PRIMARY:
2171 		if (net->sctp.addip_enable)
2172 			break;
2173 		goto fallthrough;
2174 
2175 	case SCTP_PARAM_HOST_NAME_ADDRESS:
2176 		/* Tell the peer, we won't support this param.  */
2177 		sctp_process_hn_param(asoc, param, chunk, err_chunk);
2178 		retval = SCTP_IERROR_ABORT;
2179 		break;
2180 
2181 	case SCTP_PARAM_FWD_TSN_SUPPORT:
2182 		if (ep->prsctp_enable)
2183 			break;
2184 		goto fallthrough;
2185 
2186 	case SCTP_PARAM_RANDOM:
2187 		if (!ep->auth_enable)
2188 			goto fallthrough;
2189 
2190 		/* SCTP-AUTH: Secion 6.1
2191 		 * If the random number is not 32 byte long the association
2192 		 * MUST be aborted.  The ABORT chunk SHOULD contain the error
2193 		 * cause 'Protocol Violation'.
2194 		 */
2195 		if (SCTP_AUTH_RANDOM_LENGTH != ntohs(param.p->length) -
2196 					       sizeof(struct sctp_paramhdr)) {
2197 			sctp_process_inv_paramlength(asoc, param.p,
2198 						     chunk, err_chunk);
2199 			retval = SCTP_IERROR_ABORT;
2200 		}
2201 		break;
2202 
2203 	case SCTP_PARAM_CHUNKS:
2204 		if (!ep->auth_enable)
2205 			goto fallthrough;
2206 
2207 		/* SCTP-AUTH: Section 3.2
2208 		 * The CHUNKS parameter MUST be included once in the INIT or
2209 		 *  INIT-ACK chunk if the sender wants to receive authenticated
2210 		 *  chunks.  Its maximum length is 260 bytes.
2211 		 */
2212 		if (260 < ntohs(param.p->length)) {
2213 			sctp_process_inv_paramlength(asoc, param.p,
2214 						     chunk, err_chunk);
2215 			retval = SCTP_IERROR_ABORT;
2216 		}
2217 		break;
2218 
2219 	case SCTP_PARAM_HMAC_ALGO:
2220 		if (!ep->auth_enable)
2221 			goto fallthrough;
2222 
2223 		hmacs = (struct sctp_hmac_algo_param *)param.p;
2224 		n_elt = (ntohs(param.p->length) -
2225 			 sizeof(struct sctp_paramhdr)) >> 1;
2226 
2227 		/* SCTP-AUTH: Section 6.1
2228 		 * The HMAC algorithm based on SHA-1 MUST be supported and
2229 		 * included in the HMAC-ALGO parameter.
2230 		 */
2231 		for (i = 0; i < n_elt; i++) {
2232 			id = ntohs(hmacs->hmac_ids[i]);
2233 
2234 			if (id == SCTP_AUTH_HMAC_ID_SHA1)
2235 				break;
2236 		}
2237 
2238 		if (id != SCTP_AUTH_HMAC_ID_SHA1) {
2239 			sctp_process_inv_paramlength(asoc, param.p, chunk,
2240 						     err_chunk);
2241 			retval = SCTP_IERROR_ABORT;
2242 		}
2243 		break;
2244 fallthrough:
2245 	default:
2246 		pr_debug("%s: unrecognized param:%d for chunk:%d\n",
2247 			 __func__, ntohs(param.p->type), cid);
2248 
2249 		retval = sctp_process_unk_param(asoc, param, chunk, err_chunk);
2250 		break;
2251 	}
2252 	return retval;
2253 }
2254 
2255 /* Verify the INIT packet before we process it.  */
2256 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
2257 		     const struct sctp_association *asoc, enum sctp_cid cid,
2258 		     struct sctp_init_chunk *peer_init,
2259 		     struct sctp_chunk *chunk, struct sctp_chunk **errp)
2260 {
2261 	union sctp_params param;
2262 	bool has_cookie = false;
2263 	int result;
2264 
2265 	/* Check for missing mandatory parameters. Note: Initial TSN is
2266 	 * also mandatory, but is not checked here since the valid range
2267 	 * is 0..2**32-1. RFC4960, section 3.3.3.
2268 	 */
2269 	if (peer_init->init_hdr.num_outbound_streams == 0 ||
2270 	    peer_init->init_hdr.num_inbound_streams == 0 ||
2271 	    peer_init->init_hdr.init_tag == 0 ||
2272 	    ntohl(peer_init->init_hdr.a_rwnd) < SCTP_DEFAULT_MINWINDOW)
2273 		return sctp_process_inv_mandatory(asoc, chunk, errp);
2274 
2275 	sctp_walk_params(param, peer_init, init_hdr.params) {
2276 		if (param.p->type == SCTP_PARAM_STATE_COOKIE)
2277 			has_cookie = true;
2278 	}
2279 
2280 	/* There is a possibility that a parameter length was bad and
2281 	 * in that case we would have stoped walking the parameters.
2282 	 * The current param.p would point at the bad one.
2283 	 * Current consensus on the mailing list is to generate a PROTOCOL
2284 	 * VIOLATION error.  We build the ERROR chunk here and let the normal
2285 	 * error handling code build and send the packet.
2286 	 */
2287 	if (param.v != (void *)chunk->chunk_end)
2288 		return sctp_process_inv_paramlength(asoc, param.p, chunk, errp);
2289 
2290 	/* The only missing mandatory param possible today is
2291 	 * the state cookie for an INIT-ACK chunk.
2292 	 */
2293 	if ((SCTP_CID_INIT_ACK == cid) && !has_cookie)
2294 		return sctp_process_missing_param(asoc, SCTP_PARAM_STATE_COOKIE,
2295 						  chunk, errp);
2296 
2297 	/* Verify all the variable length parameters */
2298 	sctp_walk_params(param, peer_init, init_hdr.params) {
2299 		result = sctp_verify_param(net, ep, asoc, param, cid,
2300 					   chunk, errp);
2301 		switch (result) {
2302 		case SCTP_IERROR_ABORT:
2303 		case SCTP_IERROR_NOMEM:
2304 			return 0;
2305 		case SCTP_IERROR_ERROR:
2306 			return 1;
2307 		case SCTP_IERROR_NO_ERROR:
2308 		default:
2309 			break;
2310 		}
2311 
2312 	} /* for (loop through all parameters) */
2313 
2314 	return 1;
2315 }
2316 
2317 /* Unpack the parameters in an INIT packet into an association.
2318  * Returns 0 on failure, else success.
2319  * FIXME:  This is an association method.
2320  */
2321 int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,
2322 		      const union sctp_addr *peer_addr,
2323 		      struct sctp_init_chunk *peer_init, gfp_t gfp)
2324 {
2325 	struct net *net = sock_net(asoc->base.sk);
2326 	struct sctp_transport *transport;
2327 	struct list_head *pos, *temp;
2328 	union sctp_params param;
2329 	union sctp_addr addr;
2330 	struct sctp_af *af;
2331 	int src_match = 0;
2332 	char *cookie;
2333 
2334 	/* We must include the address that the INIT packet came from.
2335 	 * This is the only address that matters for an INIT packet.
2336 	 * When processing a COOKIE ECHO, we retrieve the from address
2337 	 * of the INIT from the cookie.
2338 	 */
2339 
2340 	/* This implementation defaults to making the first transport
2341 	 * added as the primary transport.  The source address seems to
2342 	 * be a a better choice than any of the embedded addresses.
2343 	 */
2344 	if (!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
2345 		goto nomem;
2346 
2347 	if (sctp_cmp_addr_exact(sctp_source(chunk), peer_addr))
2348 		src_match = 1;
2349 
2350 	/* Process the initialization parameters.  */
2351 	sctp_walk_params(param, peer_init, init_hdr.params) {
2352 		if (!src_match && (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
2353 		    param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
2354 			af = sctp_get_af_specific(param_type2af(param.p->type));
2355 			af->from_addr_param(&addr, param.addr,
2356 					    chunk->sctp_hdr->source, 0);
2357 			if (sctp_cmp_addr_exact(sctp_source(chunk), &addr))
2358 				src_match = 1;
2359 		}
2360 
2361 		if (!sctp_process_param(asoc, param, peer_addr, gfp))
2362 			goto clean_up;
2363 	}
2364 
2365 	/* source address of chunk may not match any valid address */
2366 	if (!src_match)
2367 		goto clean_up;
2368 
2369 	/* AUTH: After processing the parameters, make sure that we
2370 	 * have all the required info to potentially do authentications.
2371 	 */
2372 	if (asoc->peer.auth_capable && (!asoc->peer.peer_random ||
2373 					!asoc->peer.peer_hmacs))
2374 		asoc->peer.auth_capable = 0;
2375 
2376 	/* In a non-backward compatible mode, if the peer claims
2377 	 * support for ADD-IP but not AUTH,  the ADD-IP spec states
2378 	 * that we MUST ABORT the association. Section 6.  The section
2379 	 * also give us an option to silently ignore the packet, which
2380 	 * is what we'll do here.
2381 	 */
2382 	if (!net->sctp.addip_noauth &&
2383 	     (asoc->peer.asconf_capable && !asoc->peer.auth_capable)) {
2384 		asoc->peer.addip_disabled_mask |= (SCTP_PARAM_ADD_IP |
2385 						  SCTP_PARAM_DEL_IP |
2386 						  SCTP_PARAM_SET_PRIMARY);
2387 		asoc->peer.asconf_capable = 0;
2388 		goto clean_up;
2389 	}
2390 
2391 	/* Walk list of transports, removing transports in the UNKNOWN state. */
2392 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2393 		transport = list_entry(pos, struct sctp_transport, transports);
2394 		if (transport->state == SCTP_UNKNOWN) {
2395 			sctp_assoc_rm_peer(asoc, transport);
2396 		}
2397 	}
2398 
2399 	/* The fixed INIT headers are always in network byte
2400 	 * order.
2401 	 */
2402 	asoc->peer.i.init_tag =
2403 		ntohl(peer_init->init_hdr.init_tag);
2404 	asoc->peer.i.a_rwnd =
2405 		ntohl(peer_init->init_hdr.a_rwnd);
2406 	asoc->peer.i.num_outbound_streams =
2407 		ntohs(peer_init->init_hdr.num_outbound_streams);
2408 	asoc->peer.i.num_inbound_streams =
2409 		ntohs(peer_init->init_hdr.num_inbound_streams);
2410 	asoc->peer.i.initial_tsn =
2411 		ntohl(peer_init->init_hdr.initial_tsn);
2412 
2413 	asoc->strreset_inseq = asoc->peer.i.initial_tsn;
2414 
2415 	/* Apply the upper bounds for output streams based on peer's
2416 	 * number of inbound streams.
2417 	 */
2418 	if (asoc->c.sinit_num_ostreams  >
2419 	    ntohs(peer_init->init_hdr.num_inbound_streams)) {
2420 		asoc->c.sinit_num_ostreams =
2421 			ntohs(peer_init->init_hdr.num_inbound_streams);
2422 	}
2423 
2424 	if (asoc->c.sinit_max_instreams >
2425 	    ntohs(peer_init->init_hdr.num_outbound_streams)) {
2426 		asoc->c.sinit_max_instreams =
2427 			ntohs(peer_init->init_hdr.num_outbound_streams);
2428 	}
2429 
2430 	/* Copy Initiation tag from INIT to VT_peer in cookie.   */
2431 	asoc->c.peer_vtag = asoc->peer.i.init_tag;
2432 
2433 	/* Peer Rwnd   : Current calculated value of the peer's rwnd.  */
2434 	asoc->peer.rwnd = asoc->peer.i.a_rwnd;
2435 
2436 	/* Copy cookie in case we need to resend COOKIE-ECHO. */
2437 	cookie = asoc->peer.cookie;
2438 	if (cookie) {
2439 		asoc->peer.cookie = kmemdup(cookie, asoc->peer.cookie_len, gfp);
2440 		if (!asoc->peer.cookie)
2441 			goto clean_up;
2442 	}
2443 
2444 	/* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily
2445 	 * high (for example, implementations MAY use the size of the receiver
2446 	 * advertised window).
2447 	 */
2448 	list_for_each_entry(transport, &asoc->peer.transport_addr_list,
2449 			transports) {
2450 		transport->ssthresh = asoc->peer.i.a_rwnd;
2451 	}
2452 
2453 	/* Set up the TSN tracking pieces.  */
2454 	if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
2455 				asoc->peer.i.initial_tsn, gfp))
2456 		goto clean_up;
2457 
2458 	/* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
2459 	 *
2460 	 * The stream sequence number in all the streams shall start
2461 	 * from 0 when the association is established.  Also, when the
2462 	 * stream sequence number reaches the value 65535 the next
2463 	 * stream sequence number shall be set to 0.
2464 	 */
2465 
2466 	if (sctp_stream_init(&asoc->stream, asoc->c.sinit_num_ostreams,
2467 			     asoc->c.sinit_max_instreams, gfp))
2468 		goto clean_up;
2469 
2470 	/* Update frag_point when stream_interleave may get changed. */
2471 	sctp_assoc_update_frag_point(asoc);
2472 
2473 	if (!asoc->temp && sctp_assoc_set_id(asoc, gfp))
2474 		goto clean_up;
2475 
2476 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
2477 	 *
2478 	 * When an endpoint has an ASCONF signaled change to be sent to the
2479 	 * remote endpoint it should do the following:
2480 	 * ...
2481 	 * A2) A serial number should be assigned to the Chunk. The serial
2482 	 * number should be a monotonically increasing number. All serial
2483 	 * numbers are defined to be initialized at the start of the
2484 	 * association to the same value as the Initial TSN.
2485 	 */
2486 	asoc->peer.addip_serial = asoc->peer.i.initial_tsn - 1;
2487 	return 1;
2488 
2489 clean_up:
2490 	/* Release the transport structures. */
2491 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2492 		transport = list_entry(pos, struct sctp_transport, transports);
2493 		if (transport->state != SCTP_ACTIVE)
2494 			sctp_assoc_rm_peer(asoc, transport);
2495 	}
2496 
2497 nomem:
2498 	return 0;
2499 }
2500 
2501 
2502 /* Update asoc with the option described in param.
2503  *
2504  * RFC2960 3.3.2.1 Optional/Variable Length Parameters in INIT
2505  *
2506  * asoc is the association to update.
2507  * param is the variable length parameter to use for update.
2508  * cid tells us if this is an INIT, INIT ACK or COOKIE ECHO.
2509  * If the current packet is an INIT we want to minimize the amount of
2510  * work we do.  In particular, we should not build transport
2511  * structures for the addresses.
2512  */
2513 static int sctp_process_param(struct sctp_association *asoc,
2514 			      union sctp_params param,
2515 			      const union sctp_addr *peer_addr,
2516 			      gfp_t gfp)
2517 {
2518 	struct net *net = sock_net(asoc->base.sk);
2519 	struct sctp_endpoint *ep = asoc->ep;
2520 	union sctp_addr_param *addr_param;
2521 	struct sctp_transport *t;
2522 	enum sctp_scope scope;
2523 	union sctp_addr addr;
2524 	struct sctp_af *af;
2525 	int retval = 1, i;
2526 	u32 stale;
2527 	__u16 sat;
2528 
2529 	/* We maintain all INIT parameters in network byte order all the
2530 	 * time.  This allows us to not worry about whether the parameters
2531 	 * came from a fresh INIT, and INIT ACK, or were stored in a cookie.
2532 	 */
2533 	switch (param.p->type) {
2534 	case SCTP_PARAM_IPV6_ADDRESS:
2535 		if (PF_INET6 != asoc->base.sk->sk_family)
2536 			break;
2537 		goto do_addr_param;
2538 
2539 	case SCTP_PARAM_IPV4_ADDRESS:
2540 		/* v4 addresses are not allowed on v6-only socket */
2541 		if (ipv6_only_sock(asoc->base.sk))
2542 			break;
2543 do_addr_param:
2544 		af = sctp_get_af_specific(param_type2af(param.p->type));
2545 		af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
2546 		scope = sctp_scope(peer_addr);
2547 		if (sctp_in_scope(net, &addr, scope))
2548 			if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
2549 				return 0;
2550 		break;
2551 
2552 	case SCTP_PARAM_COOKIE_PRESERVATIVE:
2553 		if (!net->sctp.cookie_preserve_enable)
2554 			break;
2555 
2556 		stale = ntohl(param.life->lifespan_increment);
2557 
2558 		/* Suggested Cookie Life span increment's unit is msec,
2559 		 * (1/1000sec).
2560 		 */
2561 		asoc->cookie_life = ktime_add_ms(asoc->cookie_life, stale);
2562 		break;
2563 
2564 	case SCTP_PARAM_HOST_NAME_ADDRESS:
2565 		pr_debug("%s: unimplemented SCTP_HOST_NAME_ADDRESS\n", __func__);
2566 		break;
2567 
2568 	case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2569 		/* Turn off the default values first so we'll know which
2570 		 * ones are really set by the peer.
2571 		 */
2572 		asoc->peer.ipv4_address = 0;
2573 		asoc->peer.ipv6_address = 0;
2574 
2575 		/* Assume that peer supports the address family
2576 		 * by which it sends a packet.
2577 		 */
2578 		if (peer_addr->sa.sa_family == AF_INET6)
2579 			asoc->peer.ipv6_address = 1;
2580 		else if (peer_addr->sa.sa_family == AF_INET)
2581 			asoc->peer.ipv4_address = 1;
2582 
2583 		/* Cycle through address types; avoid divide by 0. */
2584 		sat = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
2585 		if (sat)
2586 			sat /= sizeof(__u16);
2587 
2588 		for (i = 0; i < sat; ++i) {
2589 			switch (param.sat->types[i]) {
2590 			case SCTP_PARAM_IPV4_ADDRESS:
2591 				asoc->peer.ipv4_address = 1;
2592 				break;
2593 
2594 			case SCTP_PARAM_IPV6_ADDRESS:
2595 				if (PF_INET6 == asoc->base.sk->sk_family)
2596 					asoc->peer.ipv6_address = 1;
2597 				break;
2598 
2599 			case SCTP_PARAM_HOST_NAME_ADDRESS:
2600 				asoc->peer.hostname_address = 1;
2601 				break;
2602 
2603 			default: /* Just ignore anything else.  */
2604 				break;
2605 			}
2606 		}
2607 		break;
2608 
2609 	case SCTP_PARAM_STATE_COOKIE:
2610 		asoc->peer.cookie_len =
2611 			ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
2612 		asoc->peer.cookie = param.cookie->body;
2613 		break;
2614 
2615 	case SCTP_PARAM_HEARTBEAT_INFO:
2616 		/* Would be odd to receive, but it causes no problems. */
2617 		break;
2618 
2619 	case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2620 		/* Rejected during verify stage. */
2621 		break;
2622 
2623 	case SCTP_PARAM_ECN_CAPABLE:
2624 		asoc->peer.ecn_capable = 1;
2625 		break;
2626 
2627 	case SCTP_PARAM_ADAPTATION_LAYER_IND:
2628 		asoc->peer.adaptation_ind = ntohl(param.aind->adaptation_ind);
2629 		break;
2630 
2631 	case SCTP_PARAM_SET_PRIMARY:
2632 		if (!net->sctp.addip_enable)
2633 			goto fall_through;
2634 
2635 		addr_param = param.v + sizeof(struct sctp_addip_param);
2636 
2637 		af = sctp_get_af_specific(param_type2af(addr_param->p.type));
2638 		if (af == NULL)
2639 			break;
2640 
2641 		af->from_addr_param(&addr, addr_param,
2642 				    htons(asoc->peer.port), 0);
2643 
2644 		/* if the address is invalid, we can't process it.
2645 		 * XXX: see spec for what to do.
2646 		 */
2647 		if (!af->addr_valid(&addr, NULL, NULL))
2648 			break;
2649 
2650 		t = sctp_assoc_lookup_paddr(asoc, &addr);
2651 		if (!t)
2652 			break;
2653 
2654 		sctp_assoc_set_primary(asoc, t);
2655 		break;
2656 
2657 	case SCTP_PARAM_SUPPORTED_EXT:
2658 		sctp_process_ext_param(asoc, param);
2659 		break;
2660 
2661 	case SCTP_PARAM_FWD_TSN_SUPPORT:
2662 		if (asoc->prsctp_enable) {
2663 			asoc->peer.prsctp_capable = 1;
2664 			break;
2665 		}
2666 		/* Fall Through */
2667 		goto fall_through;
2668 
2669 	case SCTP_PARAM_RANDOM:
2670 		if (!ep->auth_enable)
2671 			goto fall_through;
2672 
2673 		/* Save peer's random parameter */
2674 		asoc->peer.peer_random = kmemdup(param.p,
2675 					    ntohs(param.p->length), gfp);
2676 		if (!asoc->peer.peer_random) {
2677 			retval = 0;
2678 			break;
2679 		}
2680 		break;
2681 
2682 	case SCTP_PARAM_HMAC_ALGO:
2683 		if (!ep->auth_enable)
2684 			goto fall_through;
2685 
2686 		/* Save peer's HMAC list */
2687 		asoc->peer.peer_hmacs = kmemdup(param.p,
2688 					    ntohs(param.p->length), gfp);
2689 		if (!asoc->peer.peer_hmacs) {
2690 			retval = 0;
2691 			break;
2692 		}
2693 
2694 		/* Set the default HMAC the peer requested*/
2695 		sctp_auth_asoc_set_default_hmac(asoc, param.hmac_algo);
2696 		break;
2697 
2698 	case SCTP_PARAM_CHUNKS:
2699 		if (!ep->auth_enable)
2700 			goto fall_through;
2701 
2702 		asoc->peer.peer_chunks = kmemdup(param.p,
2703 					    ntohs(param.p->length), gfp);
2704 		if (!asoc->peer.peer_chunks)
2705 			retval = 0;
2706 		break;
2707 fall_through:
2708 	default:
2709 		/* Any unrecognized parameters should have been caught
2710 		 * and handled by sctp_verify_param() which should be
2711 		 * called prior to this routine.  Simply log the error
2712 		 * here.
2713 		 */
2714 		pr_debug("%s: ignoring param:%d for association:%p.\n",
2715 			 __func__, ntohs(param.p->type), asoc);
2716 		break;
2717 	}
2718 
2719 	return retval;
2720 }
2721 
2722 /* Select a new verification tag.  */
2723 __u32 sctp_generate_tag(const struct sctp_endpoint *ep)
2724 {
2725 	/* I believe that this random number generator complies with RFC1750.
2726 	 * A tag of 0 is reserved for special cases (e.g. INIT).
2727 	 */
2728 	__u32 x;
2729 
2730 	do {
2731 		get_random_bytes(&x, sizeof(__u32));
2732 	} while (x == 0);
2733 
2734 	return x;
2735 }
2736 
2737 /* Select an initial TSN to send during startup.  */
2738 __u32 sctp_generate_tsn(const struct sctp_endpoint *ep)
2739 {
2740 	__u32 retval;
2741 
2742 	get_random_bytes(&retval, sizeof(__u32));
2743 	return retval;
2744 }
2745 
2746 /*
2747  * ADDIP 3.1.1 Address Configuration Change Chunk (ASCONF)
2748  *      0                   1                   2                   3
2749  *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
2750  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2751  *     | Type = 0xC1   |  Chunk Flags  |      Chunk Length             |
2752  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2753  *     |                       Serial Number                           |
2754  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2755  *     |                    Address Parameter                          |
2756  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2757  *     |                     ASCONF Parameter #1                       |
2758  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2759  *     \                                                               \
2760  *     /                             ....                              /
2761  *     \                                                               \
2762  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2763  *     |                     ASCONF Parameter #N                       |
2764  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2765  *
2766  * Address Parameter and other parameter will not be wrapped in this function
2767  */
2768 static struct sctp_chunk *sctp_make_asconf(struct sctp_association *asoc,
2769 					   union sctp_addr *addr,
2770 					   int vparam_len)
2771 {
2772 	struct sctp_addiphdr asconf;
2773 	struct sctp_chunk *retval;
2774 	int length = sizeof(asconf) + vparam_len;
2775 	union sctp_addr_param addrparam;
2776 	int addrlen;
2777 	struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
2778 
2779 	addrlen = af->to_addr_param(addr, &addrparam);
2780 	if (!addrlen)
2781 		return NULL;
2782 	length += addrlen;
2783 
2784 	/* Create the chunk.  */
2785 	retval = sctp_make_control(asoc, SCTP_CID_ASCONF, 0, length,
2786 				   GFP_ATOMIC);
2787 	if (!retval)
2788 		return NULL;
2789 
2790 	asconf.serial = htonl(asoc->addip_serial++);
2791 
2792 	retval->subh.addip_hdr =
2793 		sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2794 	retval->param_hdr.v =
2795 		sctp_addto_chunk(retval, addrlen, &addrparam);
2796 
2797 	return retval;
2798 }
2799 
2800 /* ADDIP
2801  * 3.2.1 Add IP Address
2802  * 	0                   1                   2                   3
2803  * 	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
2804  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2805  *     |        Type = 0xC001          |    Length = Variable          |
2806  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2807  *     |               ASCONF-Request Correlation ID                   |
2808  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2809  *     |                       Address Parameter                       |
2810  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2811  *
2812  * 3.2.2 Delete IP Address
2813  * 	0                   1                   2                   3
2814  * 	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
2815  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2816  *     |        Type = 0xC002          |    Length = Variable          |
2817  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2818  *     |               ASCONF-Request Correlation ID                   |
2819  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2820  *     |                       Address Parameter                       |
2821  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2822  *
2823  */
2824 struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *asoc,
2825 					      union sctp_addr *laddr,
2826 					      struct sockaddr *addrs,
2827 					      int addrcnt, __be16 flags)
2828 {
2829 	union sctp_addr_param addr_param;
2830 	struct sctp_addip_param	param;
2831 	int paramlen = sizeof(param);
2832 	struct sctp_chunk *retval;
2833 	int addr_param_len = 0;
2834 	union sctp_addr *addr;
2835 	int totallen = 0, i;
2836 	int del_pickup = 0;
2837 	struct sctp_af *af;
2838 	void *addr_buf;
2839 
2840 	/* Get total length of all the address parameters. */
2841 	addr_buf = addrs;
2842 	for (i = 0; i < addrcnt; i++) {
2843 		addr = addr_buf;
2844 		af = sctp_get_af_specific(addr->v4.sin_family);
2845 		addr_param_len = af->to_addr_param(addr, &addr_param);
2846 
2847 		totallen += paramlen;
2848 		totallen += addr_param_len;
2849 
2850 		addr_buf += af->sockaddr_len;
2851 		if (asoc->asconf_addr_del_pending && !del_pickup) {
2852 			/* reuse the parameter length from the same scope one */
2853 			totallen += paramlen;
2854 			totallen += addr_param_len;
2855 			del_pickup = 1;
2856 
2857 			pr_debug("%s: picked same-scope del_pending addr, "
2858 				 "totallen for all addresses is %d\n",
2859 				 __func__, totallen);
2860 		}
2861 	}
2862 
2863 	/* Create an asconf chunk with the required length. */
2864 	retval = sctp_make_asconf(asoc, laddr, totallen);
2865 	if (!retval)
2866 		return NULL;
2867 
2868 	/* Add the address parameters to the asconf chunk. */
2869 	addr_buf = addrs;
2870 	for (i = 0; i < addrcnt; i++) {
2871 		addr = addr_buf;
2872 		af = sctp_get_af_specific(addr->v4.sin_family);
2873 		addr_param_len = af->to_addr_param(addr, &addr_param);
2874 		param.param_hdr.type = flags;
2875 		param.param_hdr.length = htons(paramlen + addr_param_len);
2876 		param.crr_id = htonl(i);
2877 
2878 		sctp_addto_chunk(retval, paramlen, &param);
2879 		sctp_addto_chunk(retval, addr_param_len, &addr_param);
2880 
2881 		addr_buf += af->sockaddr_len;
2882 	}
2883 	if (flags == SCTP_PARAM_ADD_IP && del_pickup) {
2884 		addr = asoc->asconf_addr_del_pending;
2885 		af = sctp_get_af_specific(addr->v4.sin_family);
2886 		addr_param_len = af->to_addr_param(addr, &addr_param);
2887 		param.param_hdr.type = SCTP_PARAM_DEL_IP;
2888 		param.param_hdr.length = htons(paramlen + addr_param_len);
2889 		param.crr_id = htonl(i);
2890 
2891 		sctp_addto_chunk(retval, paramlen, &param);
2892 		sctp_addto_chunk(retval, addr_param_len, &addr_param);
2893 	}
2894 	return retval;
2895 }
2896 
2897 /* ADDIP
2898  * 3.2.4 Set Primary IP Address
2899  *	0                   1                   2                   3
2900  *	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
2901  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2902  *     |        Type =0xC004           |    Length = Variable          |
2903  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2904  *     |               ASCONF-Request Correlation ID                   |
2905  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2906  *     |                       Address Parameter                       |
2907  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2908  *
2909  * Create an ASCONF chunk with Set Primary IP address parameter.
2910  */
2911 struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
2912 					     union sctp_addr *addr)
2913 {
2914 	struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
2915 	union sctp_addr_param addrparam;
2916 	struct sctp_addip_param	param;
2917 	struct sctp_chunk *retval;
2918 	int len = sizeof(param);
2919 	int addrlen;
2920 
2921 	addrlen = af->to_addr_param(addr, &addrparam);
2922 	if (!addrlen)
2923 		return NULL;
2924 	len += addrlen;
2925 
2926 	/* Create the chunk and make asconf header. */
2927 	retval = sctp_make_asconf(asoc, addr, len);
2928 	if (!retval)
2929 		return NULL;
2930 
2931 	param.param_hdr.type = SCTP_PARAM_SET_PRIMARY;
2932 	param.param_hdr.length = htons(len);
2933 	param.crr_id = 0;
2934 
2935 	sctp_addto_chunk(retval, sizeof(param), &param);
2936 	sctp_addto_chunk(retval, addrlen, &addrparam);
2937 
2938 	return retval;
2939 }
2940 
2941 /* ADDIP 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
2942  *      0                   1                   2                   3
2943  *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
2944  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2945  *     | Type = 0x80   |  Chunk Flags  |      Chunk Length             |
2946  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2947  *     |                       Serial Number                           |
2948  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2949  *     |                 ASCONF Parameter Response#1                   |
2950  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2951  *     \                                                               \
2952  *     /                             ....                              /
2953  *     \                                                               \
2954  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2955  *     |                 ASCONF Parameter Response#N                   |
2956  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2957  *
2958  * Create an ASCONF_ACK chunk with enough space for the parameter responses.
2959  */
2960 static struct sctp_chunk *sctp_make_asconf_ack(const struct sctp_association *asoc,
2961 					       __u32 serial, int vparam_len)
2962 {
2963 	struct sctp_addiphdr asconf;
2964 	struct sctp_chunk *retval;
2965 	int length = sizeof(asconf) + vparam_len;
2966 
2967 	/* Create the chunk.  */
2968 	retval = sctp_make_control(asoc, SCTP_CID_ASCONF_ACK, 0, length,
2969 				   GFP_ATOMIC);
2970 	if (!retval)
2971 		return NULL;
2972 
2973 	asconf.serial = htonl(serial);
2974 
2975 	retval->subh.addip_hdr =
2976 		sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2977 
2978 	return retval;
2979 }
2980 
2981 /* Add response parameters to an ASCONF_ACK chunk. */
2982 static void sctp_add_asconf_response(struct sctp_chunk *chunk, __be32 crr_id,
2983 				     __be16 err_code,
2984 				     struct sctp_addip_param *asconf_param)
2985 {
2986 	struct sctp_addip_param ack_param;
2987 	struct sctp_errhdr err_param;
2988 	int asconf_param_len = 0;
2989 	int err_param_len = 0;
2990 	__be16 response_type;
2991 
2992 	if (SCTP_ERROR_NO_ERROR == err_code) {
2993 		response_type = SCTP_PARAM_SUCCESS_REPORT;
2994 	} else {
2995 		response_type = SCTP_PARAM_ERR_CAUSE;
2996 		err_param_len = sizeof(err_param);
2997 		if (asconf_param)
2998 			asconf_param_len =
2999 				 ntohs(asconf_param->param_hdr.length);
3000 	}
3001 
3002 	/* Add Success Indication or Error Cause Indication parameter. */
3003 	ack_param.param_hdr.type = response_type;
3004 	ack_param.param_hdr.length = htons(sizeof(ack_param) +
3005 					   err_param_len +
3006 					   asconf_param_len);
3007 	ack_param.crr_id = crr_id;
3008 	sctp_addto_chunk(chunk, sizeof(ack_param), &ack_param);
3009 
3010 	if (SCTP_ERROR_NO_ERROR == err_code)
3011 		return;
3012 
3013 	/* Add Error Cause parameter. */
3014 	err_param.cause = err_code;
3015 	err_param.length = htons(err_param_len + asconf_param_len);
3016 	sctp_addto_chunk(chunk, err_param_len, &err_param);
3017 
3018 	/* Add the failed TLV copied from ASCONF chunk. */
3019 	if (asconf_param)
3020 		sctp_addto_chunk(chunk, asconf_param_len, asconf_param);
3021 }
3022 
3023 /* Process a asconf parameter. */
3024 static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
3025 					struct sctp_chunk *asconf,
3026 					struct sctp_addip_param *asconf_param)
3027 {
3028 	union sctp_addr_param *addr_param;
3029 	struct sctp_transport *peer;
3030 	union sctp_addr	addr;
3031 	struct sctp_af *af;
3032 
3033 	addr_param = (void *)asconf_param + sizeof(*asconf_param);
3034 
3035 	if (asconf_param->param_hdr.type != SCTP_PARAM_ADD_IP &&
3036 	    asconf_param->param_hdr.type != SCTP_PARAM_DEL_IP &&
3037 	    asconf_param->param_hdr.type != SCTP_PARAM_SET_PRIMARY)
3038 		return SCTP_ERROR_UNKNOWN_PARAM;
3039 
3040 	switch (addr_param->p.type) {
3041 	case SCTP_PARAM_IPV6_ADDRESS:
3042 		if (!asoc->peer.ipv6_address)
3043 			return SCTP_ERROR_DNS_FAILED;
3044 		break;
3045 	case SCTP_PARAM_IPV4_ADDRESS:
3046 		if (!asoc->peer.ipv4_address)
3047 			return SCTP_ERROR_DNS_FAILED;
3048 		break;
3049 	default:
3050 		return SCTP_ERROR_DNS_FAILED;
3051 	}
3052 
3053 	af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3054 	if (unlikely(!af))
3055 		return SCTP_ERROR_DNS_FAILED;
3056 
3057 	af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);
3058 
3059 	/* ADDIP 4.2.1  This parameter MUST NOT contain a broadcast
3060 	 * or multicast address.
3061 	 * (note: wildcard is permitted and requires special handling so
3062 	 *  make sure we check for that)
3063 	 */
3064 	if (!af->is_any(&addr) && !af->addr_valid(&addr, NULL, asconf->skb))
3065 		return SCTP_ERROR_DNS_FAILED;
3066 
3067 	switch (asconf_param->param_hdr.type) {
3068 	case SCTP_PARAM_ADD_IP:
3069 		/* Section 4.2.1:
3070 		 * If the address 0.0.0.0 or ::0 is provided, the source
3071 		 * address of the packet MUST be added.
3072 		 */
3073 		if (af->is_any(&addr))
3074 			memcpy(&addr, &asconf->source, sizeof(addr));
3075 
3076 		if (security_sctp_bind_connect(asoc->ep->base.sk,
3077 					       SCTP_PARAM_ADD_IP,
3078 					       (struct sockaddr *)&addr,
3079 					       af->sockaddr_len))
3080 			return SCTP_ERROR_REQ_REFUSED;
3081 
3082 		/* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
3083 		 * request and does not have the local resources to add this
3084 		 * new address to the association, it MUST return an Error
3085 		 * Cause TLV set to the new error code 'Operation Refused
3086 		 * Due to Resource Shortage'.
3087 		 */
3088 
3089 		peer = sctp_assoc_add_peer(asoc, &addr, GFP_ATOMIC, SCTP_UNCONFIRMED);
3090 		if (!peer)
3091 			return SCTP_ERROR_RSRC_LOW;
3092 
3093 		/* Start the heartbeat timer. */
3094 		sctp_transport_reset_hb_timer(peer);
3095 		asoc->new_transport = peer;
3096 		break;
3097 	case SCTP_PARAM_DEL_IP:
3098 		/* ADDIP 4.3 D7) If a request is received to delete the
3099 		 * last remaining IP address of a peer endpoint, the receiver
3100 		 * MUST send an Error Cause TLV with the error cause set to the
3101 		 * new error code 'Request to Delete Last Remaining IP Address'.
3102 		 */
3103 		if (asoc->peer.transport_count == 1)
3104 			return SCTP_ERROR_DEL_LAST_IP;
3105 
3106 		/* ADDIP 4.3 D8) If a request is received to delete an IP
3107 		 * address which is also the source address of the IP packet
3108 		 * which contained the ASCONF chunk, the receiver MUST reject
3109 		 * this request. To reject the request the receiver MUST send
3110 		 * an Error Cause TLV set to the new error code 'Request to
3111 		 * Delete Source IP Address'
3112 		 */
3113 		if (sctp_cmp_addr_exact(&asconf->source, &addr))
3114 			return SCTP_ERROR_DEL_SRC_IP;
3115 
3116 		/* Section 4.2.2
3117 		 * If the address 0.0.0.0 or ::0 is provided, all
3118 		 * addresses of the peer except	the source address of the
3119 		 * packet MUST be deleted.
3120 		 */
3121 		if (af->is_any(&addr)) {
3122 			sctp_assoc_set_primary(asoc, asconf->transport);
3123 			sctp_assoc_del_nonprimary_peers(asoc,
3124 							asconf->transport);
3125 			return SCTP_ERROR_NO_ERROR;
3126 		}
3127 
3128 		/* If the address is not part of the association, the
3129 		 * ASCONF-ACK with Error Cause Indication Parameter
3130 		 * which including cause of Unresolvable Address should
3131 		 * be sent.
3132 		 */
3133 		peer = sctp_assoc_lookup_paddr(asoc, &addr);
3134 		if (!peer)
3135 			return SCTP_ERROR_DNS_FAILED;
3136 
3137 		sctp_assoc_rm_peer(asoc, peer);
3138 		break;
3139 	case SCTP_PARAM_SET_PRIMARY:
3140 		/* ADDIP Section 4.2.4
3141 		 * If the address 0.0.0.0 or ::0 is provided, the receiver
3142 		 * MAY mark the source address of the packet as its
3143 		 * primary.
3144 		 */
3145 		if (af->is_any(&addr))
3146 			memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));
3147 
3148 		if (security_sctp_bind_connect(asoc->ep->base.sk,
3149 					       SCTP_PARAM_SET_PRIMARY,
3150 					       (struct sockaddr *)&addr,
3151 					       af->sockaddr_len))
3152 			return SCTP_ERROR_REQ_REFUSED;
3153 
3154 		peer = sctp_assoc_lookup_paddr(asoc, &addr);
3155 		if (!peer)
3156 			return SCTP_ERROR_DNS_FAILED;
3157 
3158 		sctp_assoc_set_primary(asoc, peer);
3159 		break;
3160 	}
3161 
3162 	return SCTP_ERROR_NO_ERROR;
3163 }
3164 
3165 /* Verify the ASCONF packet before we process it. */
3166 bool sctp_verify_asconf(const struct sctp_association *asoc,
3167 			struct sctp_chunk *chunk, bool addr_param_needed,
3168 			struct sctp_paramhdr **errp)
3169 {
3170 	struct sctp_addip_chunk *addip;
3171 	bool addr_param_seen = false;
3172 	union sctp_params param;
3173 
3174 	addip = (struct sctp_addip_chunk *)chunk->chunk_hdr;
3175 	sctp_walk_params(param, addip, addip_hdr.params) {
3176 		size_t length = ntohs(param.p->length);
3177 
3178 		*errp = param.p;
3179 		switch (param.p->type) {
3180 		case SCTP_PARAM_ERR_CAUSE:
3181 			break;
3182 		case SCTP_PARAM_IPV4_ADDRESS:
3183 			if (length != sizeof(struct sctp_ipv4addr_param))
3184 				return false;
3185 			/* ensure there is only one addr param and it's in the
3186 			 * beginning of addip_hdr params, or we reject it.
3187 			 */
3188 			if (param.v != addip->addip_hdr.params)
3189 				return false;
3190 			addr_param_seen = true;
3191 			break;
3192 		case SCTP_PARAM_IPV6_ADDRESS:
3193 			if (length != sizeof(struct sctp_ipv6addr_param))
3194 				return false;
3195 			if (param.v != addip->addip_hdr.params)
3196 				return false;
3197 			addr_param_seen = true;
3198 			break;
3199 		case SCTP_PARAM_ADD_IP:
3200 		case SCTP_PARAM_DEL_IP:
3201 		case SCTP_PARAM_SET_PRIMARY:
3202 			/* In ASCONF chunks, these need to be first. */
3203 			if (addr_param_needed && !addr_param_seen)
3204 				return false;
3205 			length = ntohs(param.addip->param_hdr.length);
3206 			if (length < sizeof(struct sctp_addip_param) +
3207 				     sizeof(**errp))
3208 				return false;
3209 			break;
3210 		case SCTP_PARAM_SUCCESS_REPORT:
3211 		case SCTP_PARAM_ADAPTATION_LAYER_IND:
3212 			if (length != sizeof(struct sctp_addip_param))
3213 				return false;
3214 			break;
3215 		default:
3216 			/* This is unkown to us, reject! */
3217 			return false;
3218 		}
3219 	}
3220 
3221 	/* Remaining sanity checks. */
3222 	if (addr_param_needed && !addr_param_seen)
3223 		return false;
3224 	if (!addr_param_needed && addr_param_seen)
3225 		return false;
3226 	if (param.v != chunk->chunk_end)
3227 		return false;
3228 
3229 	return true;
3230 }
3231 
3232 /* Process an incoming ASCONF chunk with the next expected serial no. and
3233  * return an ASCONF_ACK chunk to be sent in response.
3234  */
3235 struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
3236 				       struct sctp_chunk *asconf)
3237 {
3238 	union sctp_addr_param *addr_param;
3239 	struct sctp_addip_chunk *addip;
3240 	struct sctp_chunk *asconf_ack;
3241 	bool all_param_pass = true;
3242 	struct sctp_addiphdr *hdr;
3243 	int length = 0, chunk_len;
3244 	union sctp_params param;
3245 	__be16 err_code;
3246 	__u32 serial;
3247 
3248 	addip = (struct sctp_addip_chunk *)asconf->chunk_hdr;
3249 	chunk_len = ntohs(asconf->chunk_hdr->length) -
3250 		    sizeof(struct sctp_chunkhdr);
3251 	hdr = (struct sctp_addiphdr *)asconf->skb->data;
3252 	serial = ntohl(hdr->serial);
3253 
3254 	/* Skip the addiphdr and store a pointer to address parameter.  */
3255 	length = sizeof(*hdr);
3256 	addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3257 	chunk_len -= length;
3258 
3259 	/* Skip the address parameter and store a pointer to the first
3260 	 * asconf parameter.
3261 	 */
3262 	length = ntohs(addr_param->p.length);
3263 	chunk_len -= length;
3264 
3265 	/* create an ASCONF_ACK chunk.
3266 	 * Based on the definitions of parameters, we know that the size of
3267 	 * ASCONF_ACK parameters are less than or equal to the fourfold of ASCONF
3268 	 * parameters.
3269 	 */
3270 	asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 4);
3271 	if (!asconf_ack)
3272 		goto done;
3273 
3274 	/* Process the TLVs contained within the ASCONF chunk. */
3275 	sctp_walk_params(param, addip, addip_hdr.params) {
3276 		/* Skip preceeding address parameters. */
3277 		if (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
3278 		    param.p->type == SCTP_PARAM_IPV6_ADDRESS)
3279 			continue;
3280 
3281 		err_code = sctp_process_asconf_param(asoc, asconf,
3282 						     param.addip);
3283 		/* ADDIP 4.1 A7)
3284 		 * If an error response is received for a TLV parameter,
3285 		 * all TLVs with no response before the failed TLV are
3286 		 * considered successful if not reported.  All TLVs after
3287 		 * the failed response are considered unsuccessful unless
3288 		 * a specific success indication is present for the parameter.
3289 		 */
3290 		if (err_code != SCTP_ERROR_NO_ERROR)
3291 			all_param_pass = false;
3292 		if (!all_param_pass)
3293 			sctp_add_asconf_response(asconf_ack, param.addip->crr_id,
3294 						 err_code, param.addip);
3295 
3296 		/* ADDIP 4.3 D11) When an endpoint receiving an ASCONF to add
3297 		 * an IP address sends an 'Out of Resource' in its response, it
3298 		 * MUST also fail any subsequent add or delete requests bundled
3299 		 * in the ASCONF.
3300 		 */
3301 		if (err_code == SCTP_ERROR_RSRC_LOW)
3302 			goto done;
3303 	}
3304 done:
3305 	asoc->peer.addip_serial++;
3306 
3307 	/* If we are sending a new ASCONF_ACK hold a reference to it in assoc
3308 	 * after freeing the reference to old asconf ack if any.
3309 	 */
3310 	if (asconf_ack) {
3311 		sctp_chunk_hold(asconf_ack);
3312 		list_add_tail(&asconf_ack->transmitted_list,
3313 			      &asoc->asconf_ack_list);
3314 	}
3315 
3316 	return asconf_ack;
3317 }
3318 
3319 /* Process a asconf parameter that is successfully acked. */
3320 static void sctp_asconf_param_success(struct sctp_association *asoc,
3321 				      struct sctp_addip_param *asconf_param)
3322 {
3323 	struct sctp_bind_addr *bp = &asoc->base.bind_addr;
3324 	union sctp_addr_param *addr_param;
3325 	struct sctp_sockaddr_entry *saddr;
3326 	struct sctp_transport *transport;
3327 	union sctp_addr	addr;
3328 	struct sctp_af *af;
3329 
3330 	addr_param = (void *)asconf_param + sizeof(*asconf_param);
3331 
3332 	/* We have checked the packet before, so we do not check again.	*/
3333 	af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3334 	af->from_addr_param(&addr, addr_param, htons(bp->port), 0);
3335 
3336 	switch (asconf_param->param_hdr.type) {
3337 	case SCTP_PARAM_ADD_IP:
3338 		/* This is always done in BH context with a socket lock
3339 		 * held, so the list can not change.
3340 		 */
3341 		local_bh_disable();
3342 		list_for_each_entry(saddr, &bp->address_list, list) {
3343 			if (sctp_cmp_addr_exact(&saddr->a, &addr))
3344 				saddr->state = SCTP_ADDR_SRC;
3345 		}
3346 		local_bh_enable();
3347 		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3348 				transports) {
3349 			sctp_transport_dst_release(transport);
3350 		}
3351 		break;
3352 	case SCTP_PARAM_DEL_IP:
3353 		local_bh_disable();
3354 		sctp_del_bind_addr(bp, &addr);
3355 		if (asoc->asconf_addr_del_pending != NULL &&
3356 		    sctp_cmp_addr_exact(asoc->asconf_addr_del_pending, &addr)) {
3357 			kfree(asoc->asconf_addr_del_pending);
3358 			asoc->asconf_addr_del_pending = NULL;
3359 		}
3360 		local_bh_enable();
3361 		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3362 				transports) {
3363 			sctp_transport_dst_release(transport);
3364 		}
3365 		break;
3366 	default:
3367 		break;
3368 	}
3369 }
3370 
3371 /* Get the corresponding ASCONF response error code from the ASCONF_ACK chunk
3372  * for the given asconf parameter.  If there is no response for this parameter,
3373  * return the error code based on the third argument 'no_err'.
3374  * ADDIP 4.1
3375  * A7) If an error response is received for a TLV parameter, all TLVs with no
3376  * response before the failed TLV are considered successful if not reported.
3377  * All TLVs after the failed response are considered unsuccessful unless a
3378  * specific success indication is present for the parameter.
3379  */
3380 static __be16 sctp_get_asconf_response(struct sctp_chunk *asconf_ack,
3381 				       struct sctp_addip_param *asconf_param,
3382 				       int no_err)
3383 {
3384 	struct sctp_addip_param	*asconf_ack_param;
3385 	struct sctp_errhdr *err_param;
3386 	int asconf_ack_len;
3387 	__be16 err_code;
3388 	int length;
3389 
3390 	if (no_err)
3391 		err_code = SCTP_ERROR_NO_ERROR;
3392 	else
3393 		err_code = SCTP_ERROR_REQ_REFUSED;
3394 
3395 	asconf_ack_len = ntohs(asconf_ack->chunk_hdr->length) -
3396 			 sizeof(struct sctp_chunkhdr);
3397 
3398 	/* Skip the addiphdr from the asconf_ack chunk and store a pointer to
3399 	 * the first asconf_ack parameter.
3400 	 */
3401 	length = sizeof(struct sctp_addiphdr);
3402 	asconf_ack_param = (struct sctp_addip_param *)(asconf_ack->skb->data +
3403 						       length);
3404 	asconf_ack_len -= length;
3405 
3406 	while (asconf_ack_len > 0) {
3407 		if (asconf_ack_param->crr_id == asconf_param->crr_id) {
3408 			switch (asconf_ack_param->param_hdr.type) {
3409 			case SCTP_PARAM_SUCCESS_REPORT:
3410 				return SCTP_ERROR_NO_ERROR;
3411 			case SCTP_PARAM_ERR_CAUSE:
3412 				length = sizeof(*asconf_ack_param);
3413 				err_param = (void *)asconf_ack_param + length;
3414 				asconf_ack_len -= length;
3415 				if (asconf_ack_len > 0)
3416 					return err_param->cause;
3417 				else
3418 					return SCTP_ERROR_INV_PARAM;
3419 				break;
3420 			default:
3421 				return SCTP_ERROR_INV_PARAM;
3422 			}
3423 		}
3424 
3425 		length = ntohs(asconf_ack_param->param_hdr.length);
3426 		asconf_ack_param = (void *)asconf_ack_param + length;
3427 		asconf_ack_len -= length;
3428 	}
3429 
3430 	return err_code;
3431 }
3432 
3433 /* Process an incoming ASCONF_ACK chunk against the cached last ASCONF chunk. */
3434 int sctp_process_asconf_ack(struct sctp_association *asoc,
3435 			    struct sctp_chunk *asconf_ack)
3436 {
3437 	struct sctp_chunk *asconf = asoc->addip_last_asconf;
3438 	struct sctp_addip_param *asconf_param;
3439 	__be16 err_code = SCTP_ERROR_NO_ERROR;
3440 	union sctp_addr_param *addr_param;
3441 	int asconf_len = asconf->skb->len;
3442 	int all_param_pass = 0;
3443 	int length = 0;
3444 	int no_err = 1;
3445 	int retval = 0;
3446 
3447 	/* Skip the chunkhdr and addiphdr from the last asconf sent and store
3448 	 * a pointer to address parameter.
3449 	 */
3450 	length = sizeof(struct sctp_addip_chunk);
3451 	addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3452 	asconf_len -= length;
3453 
3454 	/* Skip the address parameter in the last asconf sent and store a
3455 	 * pointer to the first asconf parameter.
3456 	 */
3457 	length = ntohs(addr_param->p.length);
3458 	asconf_param = (void *)addr_param + length;
3459 	asconf_len -= length;
3460 
3461 	/* ADDIP 4.1
3462 	 * A8) If there is no response(s) to specific TLV parameter(s), and no
3463 	 * failures are indicated, then all request(s) are considered
3464 	 * successful.
3465 	 */
3466 	if (asconf_ack->skb->len == sizeof(struct sctp_addiphdr))
3467 		all_param_pass = 1;
3468 
3469 	/* Process the TLVs contained in the last sent ASCONF chunk. */
3470 	while (asconf_len > 0) {
3471 		if (all_param_pass)
3472 			err_code = SCTP_ERROR_NO_ERROR;
3473 		else {
3474 			err_code = sctp_get_asconf_response(asconf_ack,
3475 							    asconf_param,
3476 							    no_err);
3477 			if (no_err && (SCTP_ERROR_NO_ERROR != err_code))
3478 				no_err = 0;
3479 		}
3480 
3481 		switch (err_code) {
3482 		case SCTP_ERROR_NO_ERROR:
3483 			sctp_asconf_param_success(asoc, asconf_param);
3484 			break;
3485 
3486 		case SCTP_ERROR_RSRC_LOW:
3487 			retval = 1;
3488 			break;
3489 
3490 		case SCTP_ERROR_UNKNOWN_PARAM:
3491 			/* Disable sending this type of asconf parameter in
3492 			 * future.
3493 			 */
3494 			asoc->peer.addip_disabled_mask |=
3495 				asconf_param->param_hdr.type;
3496 			break;
3497 
3498 		case SCTP_ERROR_REQ_REFUSED:
3499 		case SCTP_ERROR_DEL_LAST_IP:
3500 		case SCTP_ERROR_DEL_SRC_IP:
3501 		default:
3502 			 break;
3503 		}
3504 
3505 		/* Skip the processed asconf parameter and move to the next
3506 		 * one.
3507 		 */
3508 		length = ntohs(asconf_param->param_hdr.length);
3509 		asconf_param = (void *)asconf_param + length;
3510 		asconf_len -= length;
3511 	}
3512 
3513 	if (no_err && asoc->src_out_of_asoc_ok) {
3514 		asoc->src_out_of_asoc_ok = 0;
3515 		sctp_transport_immediate_rtx(asoc->peer.primary_path);
3516 	}
3517 
3518 	/* Free the cached last sent asconf chunk. */
3519 	list_del_init(&asconf->transmitted_list);
3520 	sctp_chunk_free(asconf);
3521 	asoc->addip_last_asconf = NULL;
3522 
3523 	return retval;
3524 }
3525 
3526 /* Make a FWD TSN chunk. */
3527 struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
3528 				    __u32 new_cum_tsn, size_t nstreams,
3529 				    struct sctp_fwdtsn_skip *skiplist)
3530 {
3531 	struct sctp_chunk *retval = NULL;
3532 	struct sctp_fwdtsn_hdr ftsn_hdr;
3533 	struct sctp_fwdtsn_skip skip;
3534 	size_t hint;
3535 	int i;
3536 
3537 	hint = (nstreams + 1) * sizeof(__u32);
3538 
3539 	retval = sctp_make_control(asoc, SCTP_CID_FWD_TSN, 0, hint, GFP_ATOMIC);
3540 
3541 	if (!retval)
3542 		return NULL;
3543 
3544 	ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
3545 	retval->subh.fwdtsn_hdr =
3546 		sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
3547 
3548 	for (i = 0; i < nstreams; i++) {
3549 		skip.stream = skiplist[i].stream;
3550 		skip.ssn = skiplist[i].ssn;
3551 		sctp_addto_chunk(retval, sizeof(skip), &skip);
3552 	}
3553 
3554 	return retval;
3555 }
3556 
3557 struct sctp_chunk *sctp_make_ifwdtsn(const struct sctp_association *asoc,
3558 				     __u32 new_cum_tsn, size_t nstreams,
3559 				     struct sctp_ifwdtsn_skip *skiplist)
3560 {
3561 	struct sctp_chunk *retval = NULL;
3562 	struct sctp_ifwdtsn_hdr ftsn_hdr;
3563 	size_t hint;
3564 
3565 	hint = (nstreams + 1) * sizeof(__u32);
3566 
3567 	retval = sctp_make_control(asoc, SCTP_CID_I_FWD_TSN, 0, hint,
3568 				   GFP_ATOMIC);
3569 	if (!retval)
3570 		return NULL;
3571 
3572 	ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
3573 	retval->subh.ifwdtsn_hdr =
3574 		sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
3575 
3576 	sctp_addto_chunk(retval, nstreams * sizeof(skiplist[0]), skiplist);
3577 
3578 	return retval;
3579 }
3580 
3581 /* RE-CONFIG 3.1 (RE-CONFIG chunk)
3582  *   0                   1                   2                   3
3583  *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
3584  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3585  *  | Type = 130    |  Chunk Flags  |      Chunk Length             |
3586  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3587  *  \                                                               \
3588  *  /                  Re-configuration Parameter                   /
3589  *  \                                                               \
3590  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3591  *  \                                                               \
3592  *  /             Re-configuration Parameter (optional)             /
3593  *  \                                                               \
3594  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3595  */
3596 static struct sctp_chunk *sctp_make_reconf(const struct sctp_association *asoc,
3597 					   int length)
3598 {
3599 	struct sctp_reconf_chunk *reconf;
3600 	struct sctp_chunk *retval;
3601 
3602 	retval = sctp_make_control(asoc, SCTP_CID_RECONF, 0, length,
3603 				   GFP_ATOMIC);
3604 	if (!retval)
3605 		return NULL;
3606 
3607 	reconf = (struct sctp_reconf_chunk *)retval->chunk_hdr;
3608 	retval->param_hdr.v = reconf->params;
3609 
3610 	return retval;
3611 }
3612 
3613 /* RE-CONFIG 4.1 (STREAM OUT RESET)
3614  *   0                   1                   2                   3
3615  *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
3616  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3617  *  |     Parameter Type = 13       | Parameter Length = 16 + 2 * N |
3618  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3619  *  |           Re-configuration Request Sequence Number            |
3620  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3621  *  |           Re-configuration Response Sequence Number           |
3622  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3623  *  |                Sender's Last Assigned TSN                     |
3624  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3625  *  |  Stream Number 1 (optional)   |    Stream Number 2 (optional) |
3626  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3627  *  /                            ......                             /
3628  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3629  *  |  Stream Number N-1 (optional) |    Stream Number N (optional) |
3630  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3631  *
3632  * RE-CONFIG 4.2 (STREAM IN RESET)
3633  *   0                   1                   2                   3
3634  *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
3635  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3636  *  |     Parameter Type = 14       |  Parameter Length = 8 + 2 * N |
3637  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3638  *  |          Re-configuration Request Sequence Number             |
3639  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3640  *  |  Stream Number 1 (optional)   |    Stream Number 2 (optional) |
3641  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3642  *  /                            ......                             /
3643  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3644  *  |  Stream Number N-1 (optional) |    Stream Number N (optional) |
3645  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3646  */
3647 struct sctp_chunk *sctp_make_strreset_req(
3648 					const struct sctp_association *asoc,
3649 					__u16 stream_num, __be16 *stream_list,
3650 					bool out, bool in)
3651 {
3652 	__u16 stream_len = stream_num * sizeof(__u16);
3653 	struct sctp_strreset_outreq outreq;
3654 	struct sctp_strreset_inreq inreq;
3655 	struct sctp_chunk *retval;
3656 	__u16 outlen, inlen;
3657 
3658 	outlen = (sizeof(outreq) + stream_len) * out;
3659 	inlen = (sizeof(inreq) + stream_len) * in;
3660 
3661 	retval = sctp_make_reconf(asoc, outlen + inlen);
3662 	if (!retval)
3663 		return NULL;
3664 
3665 	if (outlen) {
3666 		outreq.param_hdr.type = SCTP_PARAM_RESET_OUT_REQUEST;
3667 		outreq.param_hdr.length = htons(outlen);
3668 		outreq.request_seq = htonl(asoc->strreset_outseq);
3669 		outreq.response_seq = htonl(asoc->strreset_inseq - 1);
3670 		outreq.send_reset_at_tsn = htonl(asoc->next_tsn - 1);
3671 
3672 		sctp_addto_chunk(retval, sizeof(outreq), &outreq);
3673 
3674 		if (stream_len)
3675 			sctp_addto_chunk(retval, stream_len, stream_list);
3676 	}
3677 
3678 	if (inlen) {
3679 		inreq.param_hdr.type = SCTP_PARAM_RESET_IN_REQUEST;
3680 		inreq.param_hdr.length = htons(inlen);
3681 		inreq.request_seq = htonl(asoc->strreset_outseq + out);
3682 
3683 		sctp_addto_chunk(retval, sizeof(inreq), &inreq);
3684 
3685 		if (stream_len)
3686 			sctp_addto_chunk(retval, stream_len, stream_list);
3687 	}
3688 
3689 	return retval;
3690 }
3691 
3692 /* RE-CONFIG 4.3 (SSN/TSN RESET ALL)
3693  *   0                   1                   2                   3
3694  *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
3695  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3696  *  |     Parameter Type = 15       |      Parameter Length = 8     |
3697  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3698  *  |         Re-configuration Request Sequence Number              |
3699  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3700  */
3701 struct sctp_chunk *sctp_make_strreset_tsnreq(
3702 					const struct sctp_association *asoc)
3703 {
3704 	struct sctp_strreset_tsnreq tsnreq;
3705 	__u16 length = sizeof(tsnreq);
3706 	struct sctp_chunk *retval;
3707 
3708 	retval = sctp_make_reconf(asoc, length);
3709 	if (!retval)
3710 		return NULL;
3711 
3712 	tsnreq.param_hdr.type = SCTP_PARAM_RESET_TSN_REQUEST;
3713 	tsnreq.param_hdr.length = htons(length);
3714 	tsnreq.request_seq = htonl(asoc->strreset_outseq);
3715 
3716 	sctp_addto_chunk(retval, sizeof(tsnreq), &tsnreq);
3717 
3718 	return retval;
3719 }
3720 
3721 /* RE-CONFIG 4.5/4.6 (ADD STREAM)
3722  *   0                   1                   2                   3
3723  *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
3724  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3725  *  |     Parameter Type = 17       |      Parameter Length = 12    |
3726  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3727  *  |          Re-configuration Request Sequence Number             |
3728  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3729  *  |      Number of new streams    |         Reserved              |
3730  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3731  */
3732 struct sctp_chunk *sctp_make_strreset_addstrm(
3733 					const struct sctp_association *asoc,
3734 					__u16 out, __u16 in)
3735 {
3736 	struct sctp_strreset_addstrm addstrm;
3737 	__u16 size = sizeof(addstrm);
3738 	struct sctp_chunk *retval;
3739 
3740 	retval = sctp_make_reconf(asoc, (!!out + !!in) * size);
3741 	if (!retval)
3742 		return NULL;
3743 
3744 	if (out) {
3745 		addstrm.param_hdr.type = SCTP_PARAM_RESET_ADD_OUT_STREAMS;
3746 		addstrm.param_hdr.length = htons(size);
3747 		addstrm.number_of_streams = htons(out);
3748 		addstrm.request_seq = htonl(asoc->strreset_outseq);
3749 		addstrm.reserved = 0;
3750 
3751 		sctp_addto_chunk(retval, size, &addstrm);
3752 	}
3753 
3754 	if (in) {
3755 		addstrm.param_hdr.type = SCTP_PARAM_RESET_ADD_IN_STREAMS;
3756 		addstrm.param_hdr.length = htons(size);
3757 		addstrm.number_of_streams = htons(in);
3758 		addstrm.request_seq = htonl(asoc->strreset_outseq + !!out);
3759 		addstrm.reserved = 0;
3760 
3761 		sctp_addto_chunk(retval, size, &addstrm);
3762 	}
3763 
3764 	return retval;
3765 }
3766 
3767 /* RE-CONFIG 4.4 (RESP)
3768  *   0                   1                   2                   3
3769  *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
3770  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3771  *  |     Parameter Type = 16       |      Parameter Length         |
3772  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3773  *  |         Re-configuration Response Sequence Number             |
3774  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3775  *  |                            Result                             |
3776  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3777  */
3778 struct sctp_chunk *sctp_make_strreset_resp(const struct sctp_association *asoc,
3779 					   __u32 result, __u32 sn)
3780 {
3781 	struct sctp_strreset_resp resp;
3782 	__u16 length = sizeof(resp);
3783 	struct sctp_chunk *retval;
3784 
3785 	retval = sctp_make_reconf(asoc, length);
3786 	if (!retval)
3787 		return NULL;
3788 
3789 	resp.param_hdr.type = SCTP_PARAM_RESET_RESPONSE;
3790 	resp.param_hdr.length = htons(length);
3791 	resp.response_seq = htonl(sn);
3792 	resp.result = htonl(result);
3793 
3794 	sctp_addto_chunk(retval, sizeof(resp), &resp);
3795 
3796 	return retval;
3797 }
3798 
3799 /* RE-CONFIG 4.4 OPTIONAL (TSNRESP)
3800  *   0                   1                   2                   3
3801  *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
3802  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3803  *  |     Parameter Type = 16       |      Parameter Length         |
3804  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3805  *  |         Re-configuration Response Sequence Number             |
3806  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3807  *  |                            Result                             |
3808  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3809  *  |                   Sender's Next TSN (optional)                |
3810  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3811  *  |                  Receiver's Next TSN (optional)               |
3812  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3813  */
3814 struct sctp_chunk *sctp_make_strreset_tsnresp(struct sctp_association *asoc,
3815 					      __u32 result, __u32 sn,
3816 					      __u32 sender_tsn,
3817 					      __u32 receiver_tsn)
3818 {
3819 	struct sctp_strreset_resptsn tsnresp;
3820 	__u16 length = sizeof(tsnresp);
3821 	struct sctp_chunk *retval;
3822 
3823 	retval = sctp_make_reconf(asoc, length);
3824 	if (!retval)
3825 		return NULL;
3826 
3827 	tsnresp.param_hdr.type = SCTP_PARAM_RESET_RESPONSE;
3828 	tsnresp.param_hdr.length = htons(length);
3829 
3830 	tsnresp.response_seq = htonl(sn);
3831 	tsnresp.result = htonl(result);
3832 	tsnresp.senders_next_tsn = htonl(sender_tsn);
3833 	tsnresp.receivers_next_tsn = htonl(receiver_tsn);
3834 
3835 	sctp_addto_chunk(retval, sizeof(tsnresp), &tsnresp);
3836 
3837 	return retval;
3838 }
3839 
3840 bool sctp_verify_reconf(const struct sctp_association *asoc,
3841 			struct sctp_chunk *chunk,
3842 			struct sctp_paramhdr **errp)
3843 {
3844 	struct sctp_reconf_chunk *hdr;
3845 	union sctp_params param;
3846 	__be16 last = 0;
3847 	__u16 cnt = 0;
3848 
3849 	hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
3850 	sctp_walk_params(param, hdr, params) {
3851 		__u16 length = ntohs(param.p->length);
3852 
3853 		*errp = param.p;
3854 		if (cnt++ > 2)
3855 			return false;
3856 		switch (param.p->type) {
3857 		case SCTP_PARAM_RESET_OUT_REQUEST:
3858 			if (length < sizeof(struct sctp_strreset_outreq) ||
3859 			    (last && last != SCTP_PARAM_RESET_RESPONSE &&
3860 			     last != SCTP_PARAM_RESET_IN_REQUEST))
3861 				return false;
3862 			break;
3863 		case SCTP_PARAM_RESET_IN_REQUEST:
3864 			if (length < sizeof(struct sctp_strreset_inreq) ||
3865 			    (last && last != SCTP_PARAM_RESET_OUT_REQUEST))
3866 				return false;
3867 			break;
3868 		case SCTP_PARAM_RESET_RESPONSE:
3869 			if ((length != sizeof(struct sctp_strreset_resp) &&
3870 			     length != sizeof(struct sctp_strreset_resptsn)) ||
3871 			    (last && last != SCTP_PARAM_RESET_RESPONSE &&
3872 			     last != SCTP_PARAM_RESET_OUT_REQUEST))
3873 				return false;
3874 			break;
3875 		case SCTP_PARAM_RESET_TSN_REQUEST:
3876 			if (length !=
3877 			    sizeof(struct sctp_strreset_tsnreq) || last)
3878 				return false;
3879 			break;
3880 		case SCTP_PARAM_RESET_ADD_IN_STREAMS:
3881 			if (length != sizeof(struct sctp_strreset_addstrm) ||
3882 			    (last && last != SCTP_PARAM_RESET_ADD_OUT_STREAMS))
3883 				return false;
3884 			break;
3885 		case SCTP_PARAM_RESET_ADD_OUT_STREAMS:
3886 			if (length != sizeof(struct sctp_strreset_addstrm) ||
3887 			    (last && last != SCTP_PARAM_RESET_ADD_IN_STREAMS))
3888 				return false;
3889 			break;
3890 		default:
3891 			return false;
3892 		}
3893 
3894 		last = param.p->type;
3895 	}
3896 
3897 	return true;
3898 }
3899