xref: /openbmc/linux/net/sctp/sm_make_chunk.c (revision 151f4e2b)
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 
1688 		err = crypto_shash_setkey(desc->tfm, ep->secret_key,
1689 					  sizeof(ep->secret_key)) ?:
1690 		      crypto_shash_digest(desc, (u8 *)&cookie->c, bodysize,
1691 					  cookie->signature);
1692 		shash_desc_zero(desc);
1693 		if (err)
1694 			goto free_cookie;
1695 	}
1696 
1697 	return retval;
1698 
1699 free_cookie:
1700 	kfree(retval);
1701 nodata:
1702 	*cookie_len = 0;
1703 	return NULL;
1704 }
1705 
1706 /* Unpack the cookie from COOKIE ECHO chunk, recreating the association.  */
1707 struct sctp_association *sctp_unpack_cookie(
1708 					const struct sctp_endpoint *ep,
1709 					const struct sctp_association *asoc,
1710 					struct sctp_chunk *chunk, gfp_t gfp,
1711 					int *error, struct sctp_chunk **errp)
1712 {
1713 	struct sctp_association *retval = NULL;
1714 	int headersize, bodysize, fixed_size;
1715 	struct sctp_signed_cookie *cookie;
1716 	struct sk_buff *skb = chunk->skb;
1717 	struct sctp_cookie *bear_cookie;
1718 	__u8 *digest = ep->digest;
1719 	enum sctp_scope scope;
1720 	unsigned int len;
1721 	ktime_t kt;
1722 
1723 	/* Header size is static data prior to the actual cookie, including
1724 	 * any padding.
1725 	 */
1726 	headersize = sizeof(struct sctp_chunkhdr) +
1727 		     (sizeof(struct sctp_signed_cookie) -
1728 		      sizeof(struct sctp_cookie));
1729 	bodysize = ntohs(chunk->chunk_hdr->length) - headersize;
1730 	fixed_size = headersize + sizeof(struct sctp_cookie);
1731 
1732 	/* Verify that the chunk looks like it even has a cookie.
1733 	 * There must be enough room for our cookie and our peer's
1734 	 * INIT chunk.
1735 	 */
1736 	len = ntohs(chunk->chunk_hdr->length);
1737 	if (len < fixed_size + sizeof(struct sctp_chunkhdr))
1738 		goto malformed;
1739 
1740 	/* Verify that the cookie has been padded out. */
1741 	if (bodysize % SCTP_COOKIE_MULTIPLE)
1742 		goto malformed;
1743 
1744 	/* Process the cookie.  */
1745 	cookie = chunk->subh.cookie_hdr;
1746 	bear_cookie = &cookie->c;
1747 
1748 	if (!sctp_sk(ep->base.sk)->hmac)
1749 		goto no_hmac;
1750 
1751 	/* Check the signature.  */
1752 	{
1753 		SHASH_DESC_ON_STACK(desc, sctp_sk(ep->base.sk)->hmac);
1754 		int err;
1755 
1756 		desc->tfm = sctp_sk(ep->base.sk)->hmac;
1757 
1758 		err = crypto_shash_setkey(desc->tfm, ep->secret_key,
1759 					  sizeof(ep->secret_key)) ?:
1760 		      crypto_shash_digest(desc, (u8 *)bear_cookie, bodysize,
1761 					  digest);
1762 		shash_desc_zero(desc);
1763 
1764 		if (err) {
1765 			*error = -SCTP_IERROR_NOMEM;
1766 			goto fail;
1767 		}
1768 	}
1769 
1770 	if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
1771 		*error = -SCTP_IERROR_BAD_SIG;
1772 		goto fail;
1773 	}
1774 
1775 no_hmac:
1776 	/* IG Section 2.35.2:
1777 	 *  3) Compare the port numbers and the verification tag contained
1778 	 *     within the COOKIE ECHO chunk to the actual port numbers and the
1779 	 *     verification tag within the SCTP common header of the received
1780 	 *     packet. If these values do not match the packet MUST be silently
1781 	 *     discarded,
1782 	 */
1783 	if (ntohl(chunk->sctp_hdr->vtag) != bear_cookie->my_vtag) {
1784 		*error = -SCTP_IERROR_BAD_TAG;
1785 		goto fail;
1786 	}
1787 
1788 	if (chunk->sctp_hdr->source != bear_cookie->peer_addr.v4.sin_port ||
1789 	    ntohs(chunk->sctp_hdr->dest) != bear_cookie->my_port) {
1790 		*error = -SCTP_IERROR_BAD_PORTS;
1791 		goto fail;
1792 	}
1793 
1794 	/* Check to see if the cookie is stale.  If there is already
1795 	 * an association, there is no need to check cookie's expiration
1796 	 * for init collision case of lost COOKIE ACK.
1797 	 * If skb has been timestamped, then use the stamp, otherwise
1798 	 * use current time.  This introduces a small possibility that
1799 	 * that a cookie may be considered expired, but his would only slow
1800 	 * down the new association establishment instead of every packet.
1801 	 */
1802 	if (sock_flag(ep->base.sk, SOCK_TIMESTAMP))
1803 		kt = skb_get_ktime(skb);
1804 	else
1805 		kt = ktime_get_real();
1806 
1807 	if (!asoc && ktime_before(bear_cookie->expiration, kt)) {
1808 		suseconds_t usecs = ktime_to_us(ktime_sub(kt, bear_cookie->expiration));
1809 		__be32 n = htonl(usecs);
1810 
1811 		/*
1812 		 * Section 3.3.10.3 Stale Cookie Error (3)
1813 		 *
1814 		 * Cause of error
1815 		 * ---------------
1816 		 * Stale Cookie Error:  Indicates the receipt of a valid State
1817 		 * Cookie that has expired.
1818 		 */
1819 		*errp = sctp_make_op_error(asoc, chunk,
1820 					   SCTP_ERROR_STALE_COOKIE, &n,
1821 					   sizeof(n), 0);
1822 		if (*errp)
1823 			*error = -SCTP_IERROR_STALE_COOKIE;
1824 		else
1825 			*error = -SCTP_IERROR_NOMEM;
1826 
1827 		goto fail;
1828 	}
1829 
1830 	/* Make a new base association.  */
1831 	scope = sctp_scope(sctp_source(chunk));
1832 	retval = sctp_association_new(ep, ep->base.sk, scope, gfp);
1833 	if (!retval) {
1834 		*error = -SCTP_IERROR_NOMEM;
1835 		goto fail;
1836 	}
1837 
1838 	/* Set up our peer's port number.  */
1839 	retval->peer.port = ntohs(chunk->sctp_hdr->source);
1840 
1841 	/* Populate the association from the cookie.  */
1842 	memcpy(&retval->c, bear_cookie, sizeof(*bear_cookie));
1843 
1844 	if (sctp_assoc_set_bind_addr_from_cookie(retval, bear_cookie,
1845 						 GFP_ATOMIC) < 0) {
1846 		*error = -SCTP_IERROR_NOMEM;
1847 		goto fail;
1848 	}
1849 
1850 	/* Also, add the destination address. */
1851 	if (list_empty(&retval->base.bind_addr.address_list)) {
1852 		sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest,
1853 				   sizeof(chunk->dest), SCTP_ADDR_SRC,
1854 				   GFP_ATOMIC);
1855 	}
1856 
1857 	retval->next_tsn = retval->c.initial_tsn;
1858 	retval->ctsn_ack_point = retval->next_tsn - 1;
1859 	retval->addip_serial = retval->c.initial_tsn;
1860 	retval->strreset_outseq = retval->c.initial_tsn;
1861 	retval->adv_peer_ack_point = retval->ctsn_ack_point;
1862 	retval->peer.prsctp_capable = retval->c.prsctp_capable;
1863 	retval->peer.adaptation_ind = retval->c.adaptation_ind;
1864 
1865 	/* The INIT stuff will be done by the side effects.  */
1866 	return retval;
1867 
1868 fail:
1869 	if (retval)
1870 		sctp_association_free(retval);
1871 
1872 	return NULL;
1873 
1874 malformed:
1875 	/* Yikes!  The packet is either corrupt or deliberately
1876 	 * malformed.
1877 	 */
1878 	*error = -SCTP_IERROR_MALFORMED;
1879 	goto fail;
1880 }
1881 
1882 /********************************************************************
1883  * 3rd Level Abstractions
1884  ********************************************************************/
1885 
1886 struct __sctp_missing {
1887 	__be32 num_missing;
1888 	__be16 type;
1889 }  __packed;
1890 
1891 /*
1892  * Report a missing mandatory parameter.
1893  */
1894 static int sctp_process_missing_param(const struct sctp_association *asoc,
1895 				      enum sctp_param paramtype,
1896 				      struct sctp_chunk *chunk,
1897 				      struct sctp_chunk **errp)
1898 {
1899 	struct __sctp_missing report;
1900 	__u16 len;
1901 
1902 	len = SCTP_PAD4(sizeof(report));
1903 
1904 	/* Make an ERROR chunk, preparing enough room for
1905 	 * returning multiple unknown parameters.
1906 	 */
1907 	if (!*errp)
1908 		*errp = sctp_make_op_error_space(asoc, chunk, len);
1909 
1910 	if (*errp) {
1911 		report.num_missing = htonl(1);
1912 		report.type = paramtype;
1913 		sctp_init_cause(*errp, SCTP_ERROR_MISS_PARAM,
1914 				sizeof(report));
1915 		sctp_addto_chunk(*errp, sizeof(report), &report);
1916 	}
1917 
1918 	/* Stop processing this chunk. */
1919 	return 0;
1920 }
1921 
1922 /* Report an Invalid Mandatory Parameter.  */
1923 static int sctp_process_inv_mandatory(const struct sctp_association *asoc,
1924 				      struct sctp_chunk *chunk,
1925 				      struct sctp_chunk **errp)
1926 {
1927 	/* Invalid Mandatory Parameter Error has no payload. */
1928 
1929 	if (!*errp)
1930 		*errp = sctp_make_op_error_space(asoc, chunk, 0);
1931 
1932 	if (*errp)
1933 		sctp_init_cause(*errp, SCTP_ERROR_INV_PARAM, 0);
1934 
1935 	/* Stop processing this chunk. */
1936 	return 0;
1937 }
1938 
1939 static int sctp_process_inv_paramlength(const struct sctp_association *asoc,
1940 					struct sctp_paramhdr *param,
1941 					const struct sctp_chunk *chunk,
1942 					struct sctp_chunk **errp)
1943 {
1944 	/* This is a fatal error.  Any accumulated non-fatal errors are
1945 	 * not reported.
1946 	 */
1947 	if (*errp)
1948 		sctp_chunk_free(*errp);
1949 
1950 	/* Create an error chunk and fill it in with our payload. */
1951 	*errp = sctp_make_violation_paramlen(asoc, chunk, param);
1952 
1953 	return 0;
1954 }
1955 
1956 
1957 /* Do not attempt to handle the HOST_NAME parm.  However, do
1958  * send back an indicator to the peer.
1959  */
1960 static int sctp_process_hn_param(const struct sctp_association *asoc,
1961 				 union sctp_params param,
1962 				 struct sctp_chunk *chunk,
1963 				 struct sctp_chunk **errp)
1964 {
1965 	__u16 len = ntohs(param.p->length);
1966 
1967 	/* Processing of the HOST_NAME parameter will generate an
1968 	 * ABORT.  If we've accumulated any non-fatal errors, they
1969 	 * would be unrecognized parameters and we should not include
1970 	 * them in the ABORT.
1971 	 */
1972 	if (*errp)
1973 		sctp_chunk_free(*errp);
1974 
1975 	*errp = sctp_make_op_error(asoc, chunk, SCTP_ERROR_DNS_FAILED,
1976 				   param.v, len, 0);
1977 
1978 	/* Stop processing this chunk. */
1979 	return 0;
1980 }
1981 
1982 static int sctp_verify_ext_param(struct net *net, union sctp_params param)
1983 {
1984 	__u16 num_ext = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
1985 	int have_asconf = 0;
1986 	int have_auth = 0;
1987 	int i;
1988 
1989 	for (i = 0; i < num_ext; i++) {
1990 		switch (param.ext->chunks[i]) {
1991 		case SCTP_CID_AUTH:
1992 			have_auth = 1;
1993 			break;
1994 		case SCTP_CID_ASCONF:
1995 		case SCTP_CID_ASCONF_ACK:
1996 			have_asconf = 1;
1997 			break;
1998 		}
1999 	}
2000 
2001 	/* ADD-IP Security: The draft requires us to ABORT or ignore the
2002 	 * INIT/INIT-ACK if ADD-IP is listed, but AUTH is not.  Do this
2003 	 * only if ADD-IP is turned on and we are not backward-compatible
2004 	 * mode.
2005 	 */
2006 	if (net->sctp.addip_noauth)
2007 		return 1;
2008 
2009 	if (net->sctp.addip_enable && !have_auth && have_asconf)
2010 		return 0;
2011 
2012 	return 1;
2013 }
2014 
2015 static void sctp_process_ext_param(struct sctp_association *asoc,
2016 				   union sctp_params param)
2017 {
2018 	__u16 num_ext = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
2019 	struct net *net = sock_net(asoc->base.sk);
2020 	int i;
2021 
2022 	for (i = 0; i < num_ext; i++) {
2023 		switch (param.ext->chunks[i]) {
2024 		case SCTP_CID_RECONF:
2025 			if (asoc->reconf_enable &&
2026 			    !asoc->peer.reconf_capable)
2027 				asoc->peer.reconf_capable = 1;
2028 			break;
2029 		case SCTP_CID_FWD_TSN:
2030 			if (asoc->prsctp_enable && !asoc->peer.prsctp_capable)
2031 				asoc->peer.prsctp_capable = 1;
2032 			break;
2033 		case SCTP_CID_AUTH:
2034 			/* if the peer reports AUTH, assume that he
2035 			 * supports AUTH.
2036 			 */
2037 			if (asoc->ep->auth_enable)
2038 				asoc->peer.auth_capable = 1;
2039 			break;
2040 		case SCTP_CID_ASCONF:
2041 		case SCTP_CID_ASCONF_ACK:
2042 			if (net->sctp.addip_enable)
2043 				asoc->peer.asconf_capable = 1;
2044 			break;
2045 		case SCTP_CID_I_DATA:
2046 			if (sctp_sk(asoc->base.sk)->strm_interleave)
2047 				asoc->intl_enable = 1;
2048 			break;
2049 		default:
2050 			break;
2051 		}
2052 	}
2053 }
2054 
2055 /* RFC 3.2.1 & the Implementers Guide 2.2.
2056  *
2057  * The Parameter Types are encoded such that the
2058  * highest-order two bits specify the action that must be
2059  * taken if the processing endpoint does not recognize the
2060  * Parameter Type.
2061  *
2062  * 00 - Stop processing this parameter; do not process any further
2063  * 	parameters within this chunk
2064  *
2065  * 01 - Stop processing this parameter, do not process any further
2066  *	parameters within this chunk, and report the unrecognized
2067  *	parameter in an 'Unrecognized Parameter' ERROR chunk.
2068  *
2069  * 10 - Skip this parameter and continue processing.
2070  *
2071  * 11 - Skip this parameter and continue processing but
2072  *	report the unrecognized parameter in an
2073  *	'Unrecognized Parameter' ERROR chunk.
2074  *
2075  * Return value:
2076  * 	SCTP_IERROR_NO_ERROR - continue with the chunk
2077  * 	SCTP_IERROR_ERROR    - stop and report an error.
2078  * 	SCTP_IERROR_NOMEME   - out of memory.
2079  */
2080 static enum sctp_ierror sctp_process_unk_param(
2081 					const struct sctp_association *asoc,
2082 					union sctp_params param,
2083 					struct sctp_chunk *chunk,
2084 					struct sctp_chunk **errp)
2085 {
2086 	int retval = SCTP_IERROR_NO_ERROR;
2087 
2088 	switch (param.p->type & SCTP_PARAM_ACTION_MASK) {
2089 	case SCTP_PARAM_ACTION_DISCARD:
2090 		retval =  SCTP_IERROR_ERROR;
2091 		break;
2092 	case SCTP_PARAM_ACTION_SKIP:
2093 		break;
2094 	case SCTP_PARAM_ACTION_DISCARD_ERR:
2095 		retval =  SCTP_IERROR_ERROR;
2096 		/* Fall through */
2097 	case SCTP_PARAM_ACTION_SKIP_ERR:
2098 		/* Make an ERROR chunk, preparing enough room for
2099 		 * returning multiple unknown parameters.
2100 		 */
2101 		if (!*errp) {
2102 			*errp = sctp_make_op_error_limited(asoc, chunk);
2103 			if (!*errp) {
2104 				/* If there is no memory for generating the
2105 				 * ERROR report as specified, an ABORT will be
2106 				 * triggered to the peer and the association
2107 				 * won't be established.
2108 				 */
2109 				retval = SCTP_IERROR_NOMEM;
2110 				break;
2111 			}
2112 		}
2113 
2114 		if (!sctp_init_cause(*errp, SCTP_ERROR_UNKNOWN_PARAM,
2115 				     ntohs(param.p->length)))
2116 			sctp_addto_chunk(*errp, ntohs(param.p->length),
2117 					 param.v);
2118 		break;
2119 	default:
2120 		break;
2121 	}
2122 
2123 	return retval;
2124 }
2125 
2126 /* Verify variable length parameters
2127  * Return values:
2128  * 	SCTP_IERROR_ABORT - trigger an ABORT
2129  * 	SCTP_IERROR_NOMEM - out of memory (abort)
2130  *	SCTP_IERROR_ERROR - stop processing, trigger an ERROR
2131  * 	SCTP_IERROR_NO_ERROR - continue with the chunk
2132  */
2133 static enum sctp_ierror sctp_verify_param(struct net *net,
2134 					  const struct sctp_endpoint *ep,
2135 					  const struct sctp_association *asoc,
2136 					  union sctp_params param,
2137 					  enum sctp_cid cid,
2138 					  struct sctp_chunk *chunk,
2139 					  struct sctp_chunk **err_chunk)
2140 {
2141 	struct sctp_hmac_algo_param *hmacs;
2142 	int retval = SCTP_IERROR_NO_ERROR;
2143 	__u16 n_elt, id = 0;
2144 	int i;
2145 
2146 	/* FIXME - This routine is not looking at each parameter per the
2147 	 * chunk type, i.e., unrecognized parameters should be further
2148 	 * identified based on the chunk id.
2149 	 */
2150 
2151 	switch (param.p->type) {
2152 	case SCTP_PARAM_IPV4_ADDRESS:
2153 	case SCTP_PARAM_IPV6_ADDRESS:
2154 	case SCTP_PARAM_COOKIE_PRESERVATIVE:
2155 	case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2156 	case SCTP_PARAM_STATE_COOKIE:
2157 	case SCTP_PARAM_HEARTBEAT_INFO:
2158 	case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2159 	case SCTP_PARAM_ECN_CAPABLE:
2160 	case SCTP_PARAM_ADAPTATION_LAYER_IND:
2161 		break;
2162 
2163 	case SCTP_PARAM_SUPPORTED_EXT:
2164 		if (!sctp_verify_ext_param(net, param))
2165 			return SCTP_IERROR_ABORT;
2166 		break;
2167 
2168 	case SCTP_PARAM_SET_PRIMARY:
2169 		if (net->sctp.addip_enable)
2170 			break;
2171 		goto fallthrough;
2172 
2173 	case SCTP_PARAM_HOST_NAME_ADDRESS:
2174 		/* Tell the peer, we won't support this param.  */
2175 		sctp_process_hn_param(asoc, param, chunk, err_chunk);
2176 		retval = SCTP_IERROR_ABORT;
2177 		break;
2178 
2179 	case SCTP_PARAM_FWD_TSN_SUPPORT:
2180 		if (ep->prsctp_enable)
2181 			break;
2182 		goto fallthrough;
2183 
2184 	case SCTP_PARAM_RANDOM:
2185 		if (!ep->auth_enable)
2186 			goto fallthrough;
2187 
2188 		/* SCTP-AUTH: Secion 6.1
2189 		 * If the random number is not 32 byte long the association
2190 		 * MUST be aborted.  The ABORT chunk SHOULD contain the error
2191 		 * cause 'Protocol Violation'.
2192 		 */
2193 		if (SCTP_AUTH_RANDOM_LENGTH != ntohs(param.p->length) -
2194 					       sizeof(struct sctp_paramhdr)) {
2195 			sctp_process_inv_paramlength(asoc, param.p,
2196 						     chunk, err_chunk);
2197 			retval = SCTP_IERROR_ABORT;
2198 		}
2199 		break;
2200 
2201 	case SCTP_PARAM_CHUNKS:
2202 		if (!ep->auth_enable)
2203 			goto fallthrough;
2204 
2205 		/* SCTP-AUTH: Section 3.2
2206 		 * The CHUNKS parameter MUST be included once in the INIT or
2207 		 *  INIT-ACK chunk if the sender wants to receive authenticated
2208 		 *  chunks.  Its maximum length is 260 bytes.
2209 		 */
2210 		if (260 < ntohs(param.p->length)) {
2211 			sctp_process_inv_paramlength(asoc, param.p,
2212 						     chunk, err_chunk);
2213 			retval = SCTP_IERROR_ABORT;
2214 		}
2215 		break;
2216 
2217 	case SCTP_PARAM_HMAC_ALGO:
2218 		if (!ep->auth_enable)
2219 			goto fallthrough;
2220 
2221 		hmacs = (struct sctp_hmac_algo_param *)param.p;
2222 		n_elt = (ntohs(param.p->length) -
2223 			 sizeof(struct sctp_paramhdr)) >> 1;
2224 
2225 		/* SCTP-AUTH: Section 6.1
2226 		 * The HMAC algorithm based on SHA-1 MUST be supported and
2227 		 * included in the HMAC-ALGO parameter.
2228 		 */
2229 		for (i = 0; i < n_elt; i++) {
2230 			id = ntohs(hmacs->hmac_ids[i]);
2231 
2232 			if (id == SCTP_AUTH_HMAC_ID_SHA1)
2233 				break;
2234 		}
2235 
2236 		if (id != SCTP_AUTH_HMAC_ID_SHA1) {
2237 			sctp_process_inv_paramlength(asoc, param.p, chunk,
2238 						     err_chunk);
2239 			retval = SCTP_IERROR_ABORT;
2240 		}
2241 		break;
2242 fallthrough:
2243 	default:
2244 		pr_debug("%s: unrecognized param:%d for chunk:%d\n",
2245 			 __func__, ntohs(param.p->type), cid);
2246 
2247 		retval = sctp_process_unk_param(asoc, param, chunk, err_chunk);
2248 		break;
2249 	}
2250 	return retval;
2251 }
2252 
2253 /* Verify the INIT packet before we process it.  */
2254 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
2255 		     const struct sctp_association *asoc, enum sctp_cid cid,
2256 		     struct sctp_init_chunk *peer_init,
2257 		     struct sctp_chunk *chunk, struct sctp_chunk **errp)
2258 {
2259 	union sctp_params param;
2260 	bool has_cookie = false;
2261 	int result;
2262 
2263 	/* Check for missing mandatory parameters. Note: Initial TSN is
2264 	 * also mandatory, but is not checked here since the valid range
2265 	 * is 0..2**32-1. RFC4960, section 3.3.3.
2266 	 */
2267 	if (peer_init->init_hdr.num_outbound_streams == 0 ||
2268 	    peer_init->init_hdr.num_inbound_streams == 0 ||
2269 	    peer_init->init_hdr.init_tag == 0 ||
2270 	    ntohl(peer_init->init_hdr.a_rwnd) < SCTP_DEFAULT_MINWINDOW)
2271 		return sctp_process_inv_mandatory(asoc, chunk, errp);
2272 
2273 	sctp_walk_params(param, peer_init, init_hdr.params) {
2274 		if (param.p->type == SCTP_PARAM_STATE_COOKIE)
2275 			has_cookie = true;
2276 	}
2277 
2278 	/* There is a possibility that a parameter length was bad and
2279 	 * in that case we would have stoped walking the parameters.
2280 	 * The current param.p would point at the bad one.
2281 	 * Current consensus on the mailing list is to generate a PROTOCOL
2282 	 * VIOLATION error.  We build the ERROR chunk here and let the normal
2283 	 * error handling code build and send the packet.
2284 	 */
2285 	if (param.v != (void *)chunk->chunk_end)
2286 		return sctp_process_inv_paramlength(asoc, param.p, chunk, errp);
2287 
2288 	/* The only missing mandatory param possible today is
2289 	 * the state cookie for an INIT-ACK chunk.
2290 	 */
2291 	if ((SCTP_CID_INIT_ACK == cid) && !has_cookie)
2292 		return sctp_process_missing_param(asoc, SCTP_PARAM_STATE_COOKIE,
2293 						  chunk, errp);
2294 
2295 	/* Verify all the variable length parameters */
2296 	sctp_walk_params(param, peer_init, init_hdr.params) {
2297 		result = sctp_verify_param(net, ep, asoc, param, cid,
2298 					   chunk, errp);
2299 		switch (result) {
2300 		case SCTP_IERROR_ABORT:
2301 		case SCTP_IERROR_NOMEM:
2302 			return 0;
2303 		case SCTP_IERROR_ERROR:
2304 			return 1;
2305 		case SCTP_IERROR_NO_ERROR:
2306 		default:
2307 			break;
2308 		}
2309 
2310 	} /* for (loop through all parameters) */
2311 
2312 	return 1;
2313 }
2314 
2315 /* Unpack the parameters in an INIT packet into an association.
2316  * Returns 0 on failure, else success.
2317  * FIXME:  This is an association method.
2318  */
2319 int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,
2320 		      const union sctp_addr *peer_addr,
2321 		      struct sctp_init_chunk *peer_init, gfp_t gfp)
2322 {
2323 	struct net *net = sock_net(asoc->base.sk);
2324 	struct sctp_transport *transport;
2325 	struct list_head *pos, *temp;
2326 	union sctp_params param;
2327 	union sctp_addr addr;
2328 	struct sctp_af *af;
2329 	int src_match = 0;
2330 	char *cookie;
2331 
2332 	/* We must include the address that the INIT packet came from.
2333 	 * This is the only address that matters for an INIT packet.
2334 	 * When processing a COOKIE ECHO, we retrieve the from address
2335 	 * of the INIT from the cookie.
2336 	 */
2337 
2338 	/* This implementation defaults to making the first transport
2339 	 * added as the primary transport.  The source address seems to
2340 	 * be a a better choice than any of the embedded addresses.
2341 	 */
2342 	if (!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
2343 		goto nomem;
2344 
2345 	if (sctp_cmp_addr_exact(sctp_source(chunk), peer_addr))
2346 		src_match = 1;
2347 
2348 	/* Process the initialization parameters.  */
2349 	sctp_walk_params(param, peer_init, init_hdr.params) {
2350 		if (!src_match && (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
2351 		    param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
2352 			af = sctp_get_af_specific(param_type2af(param.p->type));
2353 			af->from_addr_param(&addr, param.addr,
2354 					    chunk->sctp_hdr->source, 0);
2355 			if (sctp_cmp_addr_exact(sctp_source(chunk), &addr))
2356 				src_match = 1;
2357 		}
2358 
2359 		if (!sctp_process_param(asoc, param, peer_addr, gfp))
2360 			goto clean_up;
2361 	}
2362 
2363 	/* source address of chunk may not match any valid address */
2364 	if (!src_match)
2365 		goto clean_up;
2366 
2367 	/* AUTH: After processing the parameters, make sure that we
2368 	 * have all the required info to potentially do authentications.
2369 	 */
2370 	if (asoc->peer.auth_capable && (!asoc->peer.peer_random ||
2371 					!asoc->peer.peer_hmacs))
2372 		asoc->peer.auth_capable = 0;
2373 
2374 	/* In a non-backward compatible mode, if the peer claims
2375 	 * support for ADD-IP but not AUTH,  the ADD-IP spec states
2376 	 * that we MUST ABORT the association. Section 6.  The section
2377 	 * also give us an option to silently ignore the packet, which
2378 	 * is what we'll do here.
2379 	 */
2380 	if (!net->sctp.addip_noauth &&
2381 	     (asoc->peer.asconf_capable && !asoc->peer.auth_capable)) {
2382 		asoc->peer.addip_disabled_mask |= (SCTP_PARAM_ADD_IP |
2383 						  SCTP_PARAM_DEL_IP |
2384 						  SCTP_PARAM_SET_PRIMARY);
2385 		asoc->peer.asconf_capable = 0;
2386 		goto clean_up;
2387 	}
2388 
2389 	/* Walk list of transports, removing transports in the UNKNOWN state. */
2390 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2391 		transport = list_entry(pos, struct sctp_transport, transports);
2392 		if (transport->state == SCTP_UNKNOWN) {
2393 			sctp_assoc_rm_peer(asoc, transport);
2394 		}
2395 	}
2396 
2397 	/* The fixed INIT headers are always in network byte
2398 	 * order.
2399 	 */
2400 	asoc->peer.i.init_tag =
2401 		ntohl(peer_init->init_hdr.init_tag);
2402 	asoc->peer.i.a_rwnd =
2403 		ntohl(peer_init->init_hdr.a_rwnd);
2404 	asoc->peer.i.num_outbound_streams =
2405 		ntohs(peer_init->init_hdr.num_outbound_streams);
2406 	asoc->peer.i.num_inbound_streams =
2407 		ntohs(peer_init->init_hdr.num_inbound_streams);
2408 	asoc->peer.i.initial_tsn =
2409 		ntohl(peer_init->init_hdr.initial_tsn);
2410 
2411 	asoc->strreset_inseq = asoc->peer.i.initial_tsn;
2412 
2413 	/* Apply the upper bounds for output streams based on peer's
2414 	 * number of inbound streams.
2415 	 */
2416 	if (asoc->c.sinit_num_ostreams  >
2417 	    ntohs(peer_init->init_hdr.num_inbound_streams)) {
2418 		asoc->c.sinit_num_ostreams =
2419 			ntohs(peer_init->init_hdr.num_inbound_streams);
2420 	}
2421 
2422 	if (asoc->c.sinit_max_instreams >
2423 	    ntohs(peer_init->init_hdr.num_outbound_streams)) {
2424 		asoc->c.sinit_max_instreams =
2425 			ntohs(peer_init->init_hdr.num_outbound_streams);
2426 	}
2427 
2428 	/* Copy Initiation tag from INIT to VT_peer in cookie.   */
2429 	asoc->c.peer_vtag = asoc->peer.i.init_tag;
2430 
2431 	/* Peer Rwnd   : Current calculated value of the peer's rwnd.  */
2432 	asoc->peer.rwnd = asoc->peer.i.a_rwnd;
2433 
2434 	/* Copy cookie in case we need to resend COOKIE-ECHO. */
2435 	cookie = asoc->peer.cookie;
2436 	if (cookie) {
2437 		asoc->peer.cookie = kmemdup(cookie, asoc->peer.cookie_len, gfp);
2438 		if (!asoc->peer.cookie)
2439 			goto clean_up;
2440 	}
2441 
2442 	/* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily
2443 	 * high (for example, implementations MAY use the size of the receiver
2444 	 * advertised window).
2445 	 */
2446 	list_for_each_entry(transport, &asoc->peer.transport_addr_list,
2447 			transports) {
2448 		transport->ssthresh = asoc->peer.i.a_rwnd;
2449 	}
2450 
2451 	/* Set up the TSN tracking pieces.  */
2452 	if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
2453 				asoc->peer.i.initial_tsn, gfp))
2454 		goto clean_up;
2455 
2456 	/* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
2457 	 *
2458 	 * The stream sequence number in all the streams shall start
2459 	 * from 0 when the association is established.  Also, when the
2460 	 * stream sequence number reaches the value 65535 the next
2461 	 * stream sequence number shall be set to 0.
2462 	 */
2463 
2464 	if (sctp_stream_init(&asoc->stream, asoc->c.sinit_num_ostreams,
2465 			     asoc->c.sinit_max_instreams, gfp))
2466 		goto clean_up;
2467 
2468 	/* Update frag_point when stream_interleave may get changed. */
2469 	sctp_assoc_update_frag_point(asoc);
2470 
2471 	if (!asoc->temp && sctp_assoc_set_id(asoc, gfp))
2472 		goto clean_up;
2473 
2474 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
2475 	 *
2476 	 * When an endpoint has an ASCONF signaled change to be sent to the
2477 	 * remote endpoint it should do the following:
2478 	 * ...
2479 	 * A2) A serial number should be assigned to the Chunk. The serial
2480 	 * number should be a monotonically increasing number. All serial
2481 	 * numbers are defined to be initialized at the start of the
2482 	 * association to the same value as the Initial TSN.
2483 	 */
2484 	asoc->peer.addip_serial = asoc->peer.i.initial_tsn - 1;
2485 	return 1;
2486 
2487 clean_up:
2488 	/* Release the transport structures. */
2489 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2490 		transport = list_entry(pos, struct sctp_transport, transports);
2491 		if (transport->state != SCTP_ACTIVE)
2492 			sctp_assoc_rm_peer(asoc, transport);
2493 	}
2494 
2495 nomem:
2496 	return 0;
2497 }
2498 
2499 
2500 /* Update asoc with the option described in param.
2501  *
2502  * RFC2960 3.3.2.1 Optional/Variable Length Parameters in INIT
2503  *
2504  * asoc is the association to update.
2505  * param is the variable length parameter to use for update.
2506  * cid tells us if this is an INIT, INIT ACK or COOKIE ECHO.
2507  * If the current packet is an INIT we want to minimize the amount of
2508  * work we do.  In particular, we should not build transport
2509  * structures for the addresses.
2510  */
2511 static int sctp_process_param(struct sctp_association *asoc,
2512 			      union sctp_params param,
2513 			      const union sctp_addr *peer_addr,
2514 			      gfp_t gfp)
2515 {
2516 	struct net *net = sock_net(asoc->base.sk);
2517 	struct sctp_endpoint *ep = asoc->ep;
2518 	union sctp_addr_param *addr_param;
2519 	struct sctp_transport *t;
2520 	enum sctp_scope scope;
2521 	union sctp_addr addr;
2522 	struct sctp_af *af;
2523 	int retval = 1, i;
2524 	u32 stale;
2525 	__u16 sat;
2526 
2527 	/* We maintain all INIT parameters in network byte order all the
2528 	 * time.  This allows us to not worry about whether the parameters
2529 	 * came from a fresh INIT, and INIT ACK, or were stored in a cookie.
2530 	 */
2531 	switch (param.p->type) {
2532 	case SCTP_PARAM_IPV6_ADDRESS:
2533 		if (PF_INET6 != asoc->base.sk->sk_family)
2534 			break;
2535 		goto do_addr_param;
2536 
2537 	case SCTP_PARAM_IPV4_ADDRESS:
2538 		/* v4 addresses are not allowed on v6-only socket */
2539 		if (ipv6_only_sock(asoc->base.sk))
2540 			break;
2541 do_addr_param:
2542 		af = sctp_get_af_specific(param_type2af(param.p->type));
2543 		af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
2544 		scope = sctp_scope(peer_addr);
2545 		if (sctp_in_scope(net, &addr, scope))
2546 			if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
2547 				return 0;
2548 		break;
2549 
2550 	case SCTP_PARAM_COOKIE_PRESERVATIVE:
2551 		if (!net->sctp.cookie_preserve_enable)
2552 			break;
2553 
2554 		stale = ntohl(param.life->lifespan_increment);
2555 
2556 		/* Suggested Cookie Life span increment's unit is msec,
2557 		 * (1/1000sec).
2558 		 */
2559 		asoc->cookie_life = ktime_add_ms(asoc->cookie_life, stale);
2560 		break;
2561 
2562 	case SCTP_PARAM_HOST_NAME_ADDRESS:
2563 		pr_debug("%s: unimplemented SCTP_HOST_NAME_ADDRESS\n", __func__);
2564 		break;
2565 
2566 	case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2567 		/* Turn off the default values first so we'll know which
2568 		 * ones are really set by the peer.
2569 		 */
2570 		asoc->peer.ipv4_address = 0;
2571 		asoc->peer.ipv6_address = 0;
2572 
2573 		/* Assume that peer supports the address family
2574 		 * by which it sends a packet.
2575 		 */
2576 		if (peer_addr->sa.sa_family == AF_INET6)
2577 			asoc->peer.ipv6_address = 1;
2578 		else if (peer_addr->sa.sa_family == AF_INET)
2579 			asoc->peer.ipv4_address = 1;
2580 
2581 		/* Cycle through address types; avoid divide by 0. */
2582 		sat = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
2583 		if (sat)
2584 			sat /= sizeof(__u16);
2585 
2586 		for (i = 0; i < sat; ++i) {
2587 			switch (param.sat->types[i]) {
2588 			case SCTP_PARAM_IPV4_ADDRESS:
2589 				asoc->peer.ipv4_address = 1;
2590 				break;
2591 
2592 			case SCTP_PARAM_IPV6_ADDRESS:
2593 				if (PF_INET6 == asoc->base.sk->sk_family)
2594 					asoc->peer.ipv6_address = 1;
2595 				break;
2596 
2597 			case SCTP_PARAM_HOST_NAME_ADDRESS:
2598 				asoc->peer.hostname_address = 1;
2599 				break;
2600 
2601 			default: /* Just ignore anything else.  */
2602 				break;
2603 			}
2604 		}
2605 		break;
2606 
2607 	case SCTP_PARAM_STATE_COOKIE:
2608 		asoc->peer.cookie_len =
2609 			ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
2610 		asoc->peer.cookie = param.cookie->body;
2611 		break;
2612 
2613 	case SCTP_PARAM_HEARTBEAT_INFO:
2614 		/* Would be odd to receive, but it causes no problems. */
2615 		break;
2616 
2617 	case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2618 		/* Rejected during verify stage. */
2619 		break;
2620 
2621 	case SCTP_PARAM_ECN_CAPABLE:
2622 		asoc->peer.ecn_capable = 1;
2623 		break;
2624 
2625 	case SCTP_PARAM_ADAPTATION_LAYER_IND:
2626 		asoc->peer.adaptation_ind = ntohl(param.aind->adaptation_ind);
2627 		break;
2628 
2629 	case SCTP_PARAM_SET_PRIMARY:
2630 		if (!net->sctp.addip_enable)
2631 			goto fall_through;
2632 
2633 		addr_param = param.v + sizeof(struct sctp_addip_param);
2634 
2635 		af = sctp_get_af_specific(param_type2af(addr_param->p.type));
2636 		if (af == NULL)
2637 			break;
2638 
2639 		af->from_addr_param(&addr, addr_param,
2640 				    htons(asoc->peer.port), 0);
2641 
2642 		/* if the address is invalid, we can't process it.
2643 		 * XXX: see spec for what to do.
2644 		 */
2645 		if (!af->addr_valid(&addr, NULL, NULL))
2646 			break;
2647 
2648 		t = sctp_assoc_lookup_paddr(asoc, &addr);
2649 		if (!t)
2650 			break;
2651 
2652 		sctp_assoc_set_primary(asoc, t);
2653 		break;
2654 
2655 	case SCTP_PARAM_SUPPORTED_EXT:
2656 		sctp_process_ext_param(asoc, param);
2657 		break;
2658 
2659 	case SCTP_PARAM_FWD_TSN_SUPPORT:
2660 		if (asoc->prsctp_enable) {
2661 			asoc->peer.prsctp_capable = 1;
2662 			break;
2663 		}
2664 		/* Fall Through */
2665 		goto fall_through;
2666 
2667 	case SCTP_PARAM_RANDOM:
2668 		if (!ep->auth_enable)
2669 			goto fall_through;
2670 
2671 		/* Save peer's random parameter */
2672 		asoc->peer.peer_random = kmemdup(param.p,
2673 					    ntohs(param.p->length), gfp);
2674 		if (!asoc->peer.peer_random) {
2675 			retval = 0;
2676 			break;
2677 		}
2678 		break;
2679 
2680 	case SCTP_PARAM_HMAC_ALGO:
2681 		if (!ep->auth_enable)
2682 			goto fall_through;
2683 
2684 		/* Save peer's HMAC list */
2685 		asoc->peer.peer_hmacs = kmemdup(param.p,
2686 					    ntohs(param.p->length), gfp);
2687 		if (!asoc->peer.peer_hmacs) {
2688 			retval = 0;
2689 			break;
2690 		}
2691 
2692 		/* Set the default HMAC the peer requested*/
2693 		sctp_auth_asoc_set_default_hmac(asoc, param.hmac_algo);
2694 		break;
2695 
2696 	case SCTP_PARAM_CHUNKS:
2697 		if (!ep->auth_enable)
2698 			goto fall_through;
2699 
2700 		asoc->peer.peer_chunks = kmemdup(param.p,
2701 					    ntohs(param.p->length), gfp);
2702 		if (!asoc->peer.peer_chunks)
2703 			retval = 0;
2704 		break;
2705 fall_through:
2706 	default:
2707 		/* Any unrecognized parameters should have been caught
2708 		 * and handled by sctp_verify_param() which should be
2709 		 * called prior to this routine.  Simply log the error
2710 		 * here.
2711 		 */
2712 		pr_debug("%s: ignoring param:%d for association:%p.\n",
2713 			 __func__, ntohs(param.p->type), asoc);
2714 		break;
2715 	}
2716 
2717 	return retval;
2718 }
2719 
2720 /* Select a new verification tag.  */
2721 __u32 sctp_generate_tag(const struct sctp_endpoint *ep)
2722 {
2723 	/* I believe that this random number generator complies with RFC1750.
2724 	 * A tag of 0 is reserved for special cases (e.g. INIT).
2725 	 */
2726 	__u32 x;
2727 
2728 	do {
2729 		get_random_bytes(&x, sizeof(__u32));
2730 	} while (x == 0);
2731 
2732 	return x;
2733 }
2734 
2735 /* Select an initial TSN to send during startup.  */
2736 __u32 sctp_generate_tsn(const struct sctp_endpoint *ep)
2737 {
2738 	__u32 retval;
2739 
2740 	get_random_bytes(&retval, sizeof(__u32));
2741 	return retval;
2742 }
2743 
2744 /*
2745  * ADDIP 3.1.1 Address Configuration Change Chunk (ASCONF)
2746  *      0                   1                   2                   3
2747  *      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
2748  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2749  *     | Type = 0xC1   |  Chunk Flags  |      Chunk Length             |
2750  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2751  *     |                       Serial Number                           |
2752  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2753  *     |                    Address Parameter                          |
2754  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2755  *     |                     ASCONF Parameter #1                       |
2756  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2757  *     \                                                               \
2758  *     /                             ....                              /
2759  *     \                                                               \
2760  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2761  *     |                     ASCONF Parameter #N                       |
2762  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2763  *
2764  * Address Parameter and other parameter will not be wrapped in this function
2765  */
2766 static struct sctp_chunk *sctp_make_asconf(struct sctp_association *asoc,
2767 					   union sctp_addr *addr,
2768 					   int vparam_len)
2769 {
2770 	struct sctp_addiphdr asconf;
2771 	struct sctp_chunk *retval;
2772 	int length = sizeof(asconf) + vparam_len;
2773 	union sctp_addr_param addrparam;
2774 	int addrlen;
2775 	struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
2776 
2777 	addrlen = af->to_addr_param(addr, &addrparam);
2778 	if (!addrlen)
2779 		return NULL;
2780 	length += addrlen;
2781 
2782 	/* Create the chunk.  */
2783 	retval = sctp_make_control(asoc, SCTP_CID_ASCONF, 0, length,
2784 				   GFP_ATOMIC);
2785 	if (!retval)
2786 		return NULL;
2787 
2788 	asconf.serial = htonl(asoc->addip_serial++);
2789 
2790 	retval->subh.addip_hdr =
2791 		sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2792 	retval->param_hdr.v =
2793 		sctp_addto_chunk(retval, addrlen, &addrparam);
2794 
2795 	return retval;
2796 }
2797 
2798 /* ADDIP
2799  * 3.2.1 Add IP Address
2800  * 	0                   1                   2                   3
2801  * 	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
2802  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2803  *     |        Type = 0xC001          |    Length = Variable          |
2804  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2805  *     |               ASCONF-Request Correlation ID                   |
2806  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2807  *     |                       Address Parameter                       |
2808  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2809  *
2810  * 3.2.2 Delete IP Address
2811  * 	0                   1                   2                   3
2812  * 	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
2813  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2814  *     |        Type = 0xC002          |    Length = Variable          |
2815  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2816  *     |               ASCONF-Request Correlation ID                   |
2817  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2818  *     |                       Address Parameter                       |
2819  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2820  *
2821  */
2822 struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *asoc,
2823 					      union sctp_addr *laddr,
2824 					      struct sockaddr *addrs,
2825 					      int addrcnt, __be16 flags)
2826 {
2827 	union sctp_addr_param addr_param;
2828 	struct sctp_addip_param	param;
2829 	int paramlen = sizeof(param);
2830 	struct sctp_chunk *retval;
2831 	int addr_param_len = 0;
2832 	union sctp_addr *addr;
2833 	int totallen = 0, i;
2834 	int del_pickup = 0;
2835 	struct sctp_af *af;
2836 	void *addr_buf;
2837 
2838 	/* Get total length of all the address parameters. */
2839 	addr_buf = addrs;
2840 	for (i = 0; i < addrcnt; i++) {
2841 		addr = addr_buf;
2842 		af = sctp_get_af_specific(addr->v4.sin_family);
2843 		addr_param_len = af->to_addr_param(addr, &addr_param);
2844 
2845 		totallen += paramlen;
2846 		totallen += addr_param_len;
2847 
2848 		addr_buf += af->sockaddr_len;
2849 		if (asoc->asconf_addr_del_pending && !del_pickup) {
2850 			/* reuse the parameter length from the same scope one */
2851 			totallen += paramlen;
2852 			totallen += addr_param_len;
2853 			del_pickup = 1;
2854 
2855 			pr_debug("%s: picked same-scope del_pending addr, "
2856 				 "totallen for all addresses is %d\n",
2857 				 __func__, totallen);
2858 		}
2859 	}
2860 
2861 	/* Create an asconf chunk with the required length. */
2862 	retval = sctp_make_asconf(asoc, laddr, totallen);
2863 	if (!retval)
2864 		return NULL;
2865 
2866 	/* Add the address parameters to the asconf chunk. */
2867 	addr_buf = addrs;
2868 	for (i = 0; i < addrcnt; i++) {
2869 		addr = addr_buf;
2870 		af = sctp_get_af_specific(addr->v4.sin_family);
2871 		addr_param_len = af->to_addr_param(addr, &addr_param);
2872 		param.param_hdr.type = flags;
2873 		param.param_hdr.length = htons(paramlen + addr_param_len);
2874 		param.crr_id = htonl(i);
2875 
2876 		sctp_addto_chunk(retval, paramlen, &param);
2877 		sctp_addto_chunk(retval, addr_param_len, &addr_param);
2878 
2879 		addr_buf += af->sockaddr_len;
2880 	}
2881 	if (flags == SCTP_PARAM_ADD_IP && del_pickup) {
2882 		addr = asoc->asconf_addr_del_pending;
2883 		af = sctp_get_af_specific(addr->v4.sin_family);
2884 		addr_param_len = af->to_addr_param(addr, &addr_param);
2885 		param.param_hdr.type = SCTP_PARAM_DEL_IP;
2886 		param.param_hdr.length = htons(paramlen + addr_param_len);
2887 		param.crr_id = htonl(i);
2888 
2889 		sctp_addto_chunk(retval, paramlen, &param);
2890 		sctp_addto_chunk(retval, addr_param_len, &addr_param);
2891 	}
2892 	return retval;
2893 }
2894 
2895 /* ADDIP
2896  * 3.2.4 Set Primary IP Address
2897  *	0                   1                   2                   3
2898  *	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
2899  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2900  *     |        Type =0xC004           |    Length = Variable          |
2901  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2902  *     |               ASCONF-Request Correlation ID                   |
2903  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2904  *     |                       Address Parameter                       |
2905  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2906  *
2907  * Create an ASCONF chunk with Set Primary IP address parameter.
2908  */
2909 struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
2910 					     union sctp_addr *addr)
2911 {
2912 	struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
2913 	union sctp_addr_param addrparam;
2914 	struct sctp_addip_param	param;
2915 	struct sctp_chunk *retval;
2916 	int len = sizeof(param);
2917 	int addrlen;
2918 
2919 	addrlen = af->to_addr_param(addr, &addrparam);
2920 	if (!addrlen)
2921 		return NULL;
2922 	len += addrlen;
2923 
2924 	/* Create the chunk and make asconf header. */
2925 	retval = sctp_make_asconf(asoc, addr, len);
2926 	if (!retval)
2927 		return NULL;
2928 
2929 	param.param_hdr.type = SCTP_PARAM_SET_PRIMARY;
2930 	param.param_hdr.length = htons(len);
2931 	param.crr_id = 0;
2932 
2933 	sctp_addto_chunk(retval, sizeof(param), &param);
2934 	sctp_addto_chunk(retval, addrlen, &addrparam);
2935 
2936 	return retval;
2937 }
2938 
2939 /* ADDIP 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
2940  *      0                   1                   2                   3
2941  *      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
2942  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2943  *     | Type = 0x80   |  Chunk Flags  |      Chunk Length             |
2944  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2945  *     |                       Serial Number                           |
2946  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2947  *     |                 ASCONF Parameter Response#1                   |
2948  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2949  *     \                                                               \
2950  *     /                             ....                              /
2951  *     \                                                               \
2952  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2953  *     |                 ASCONF Parameter Response#N                   |
2954  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2955  *
2956  * Create an ASCONF_ACK chunk with enough space for the parameter responses.
2957  */
2958 static struct sctp_chunk *sctp_make_asconf_ack(const struct sctp_association *asoc,
2959 					       __u32 serial, int vparam_len)
2960 {
2961 	struct sctp_addiphdr asconf;
2962 	struct sctp_chunk *retval;
2963 	int length = sizeof(asconf) + vparam_len;
2964 
2965 	/* Create the chunk.  */
2966 	retval = sctp_make_control(asoc, SCTP_CID_ASCONF_ACK, 0, length,
2967 				   GFP_ATOMIC);
2968 	if (!retval)
2969 		return NULL;
2970 
2971 	asconf.serial = htonl(serial);
2972 
2973 	retval->subh.addip_hdr =
2974 		sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2975 
2976 	return retval;
2977 }
2978 
2979 /* Add response parameters to an ASCONF_ACK chunk. */
2980 static void sctp_add_asconf_response(struct sctp_chunk *chunk, __be32 crr_id,
2981 				     __be16 err_code,
2982 				     struct sctp_addip_param *asconf_param)
2983 {
2984 	struct sctp_addip_param ack_param;
2985 	struct sctp_errhdr err_param;
2986 	int asconf_param_len = 0;
2987 	int err_param_len = 0;
2988 	__be16 response_type;
2989 
2990 	if (SCTP_ERROR_NO_ERROR == err_code) {
2991 		response_type = SCTP_PARAM_SUCCESS_REPORT;
2992 	} else {
2993 		response_type = SCTP_PARAM_ERR_CAUSE;
2994 		err_param_len = sizeof(err_param);
2995 		if (asconf_param)
2996 			asconf_param_len =
2997 				 ntohs(asconf_param->param_hdr.length);
2998 	}
2999 
3000 	/* Add Success Indication or Error Cause Indication parameter. */
3001 	ack_param.param_hdr.type = response_type;
3002 	ack_param.param_hdr.length = htons(sizeof(ack_param) +
3003 					   err_param_len +
3004 					   asconf_param_len);
3005 	ack_param.crr_id = crr_id;
3006 	sctp_addto_chunk(chunk, sizeof(ack_param), &ack_param);
3007 
3008 	if (SCTP_ERROR_NO_ERROR == err_code)
3009 		return;
3010 
3011 	/* Add Error Cause parameter. */
3012 	err_param.cause = err_code;
3013 	err_param.length = htons(err_param_len + asconf_param_len);
3014 	sctp_addto_chunk(chunk, err_param_len, &err_param);
3015 
3016 	/* Add the failed TLV copied from ASCONF chunk. */
3017 	if (asconf_param)
3018 		sctp_addto_chunk(chunk, asconf_param_len, asconf_param);
3019 }
3020 
3021 /* Process a asconf parameter. */
3022 static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
3023 					struct sctp_chunk *asconf,
3024 					struct sctp_addip_param *asconf_param)
3025 {
3026 	union sctp_addr_param *addr_param;
3027 	struct sctp_transport *peer;
3028 	union sctp_addr	addr;
3029 	struct sctp_af *af;
3030 
3031 	addr_param = (void *)asconf_param + sizeof(*asconf_param);
3032 
3033 	if (asconf_param->param_hdr.type != SCTP_PARAM_ADD_IP &&
3034 	    asconf_param->param_hdr.type != SCTP_PARAM_DEL_IP &&
3035 	    asconf_param->param_hdr.type != SCTP_PARAM_SET_PRIMARY)
3036 		return SCTP_ERROR_UNKNOWN_PARAM;
3037 
3038 	switch (addr_param->p.type) {
3039 	case SCTP_PARAM_IPV6_ADDRESS:
3040 		if (!asoc->peer.ipv6_address)
3041 			return SCTP_ERROR_DNS_FAILED;
3042 		break;
3043 	case SCTP_PARAM_IPV4_ADDRESS:
3044 		if (!asoc->peer.ipv4_address)
3045 			return SCTP_ERROR_DNS_FAILED;
3046 		break;
3047 	default:
3048 		return SCTP_ERROR_DNS_FAILED;
3049 	}
3050 
3051 	af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3052 	if (unlikely(!af))
3053 		return SCTP_ERROR_DNS_FAILED;
3054 
3055 	af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);
3056 
3057 	/* ADDIP 4.2.1  This parameter MUST NOT contain a broadcast
3058 	 * or multicast address.
3059 	 * (note: wildcard is permitted and requires special handling so
3060 	 *  make sure we check for that)
3061 	 */
3062 	if (!af->is_any(&addr) && !af->addr_valid(&addr, NULL, asconf->skb))
3063 		return SCTP_ERROR_DNS_FAILED;
3064 
3065 	switch (asconf_param->param_hdr.type) {
3066 	case SCTP_PARAM_ADD_IP:
3067 		/* Section 4.2.1:
3068 		 * If the address 0.0.0.0 or ::0 is provided, the source
3069 		 * address of the packet MUST be added.
3070 		 */
3071 		if (af->is_any(&addr))
3072 			memcpy(&addr, &asconf->source, sizeof(addr));
3073 
3074 		if (security_sctp_bind_connect(asoc->ep->base.sk,
3075 					       SCTP_PARAM_ADD_IP,
3076 					       (struct sockaddr *)&addr,
3077 					       af->sockaddr_len))
3078 			return SCTP_ERROR_REQ_REFUSED;
3079 
3080 		/* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
3081 		 * request and does not have the local resources to add this
3082 		 * new address to the association, it MUST return an Error
3083 		 * Cause TLV set to the new error code 'Operation Refused
3084 		 * Due to Resource Shortage'.
3085 		 */
3086 
3087 		peer = sctp_assoc_add_peer(asoc, &addr, GFP_ATOMIC, SCTP_UNCONFIRMED);
3088 		if (!peer)
3089 			return SCTP_ERROR_RSRC_LOW;
3090 
3091 		/* Start the heartbeat timer. */
3092 		sctp_transport_reset_hb_timer(peer);
3093 		asoc->new_transport = peer;
3094 		break;
3095 	case SCTP_PARAM_DEL_IP:
3096 		/* ADDIP 4.3 D7) If a request is received to delete the
3097 		 * last remaining IP address of a peer endpoint, the receiver
3098 		 * MUST send an Error Cause TLV with the error cause set to the
3099 		 * new error code 'Request to Delete Last Remaining IP Address'.
3100 		 */
3101 		if (asoc->peer.transport_count == 1)
3102 			return SCTP_ERROR_DEL_LAST_IP;
3103 
3104 		/* ADDIP 4.3 D8) If a request is received to delete an IP
3105 		 * address which is also the source address of the IP packet
3106 		 * which contained the ASCONF chunk, the receiver MUST reject
3107 		 * this request. To reject the request the receiver MUST send
3108 		 * an Error Cause TLV set to the new error code 'Request to
3109 		 * Delete Source IP Address'
3110 		 */
3111 		if (sctp_cmp_addr_exact(&asconf->source, &addr))
3112 			return SCTP_ERROR_DEL_SRC_IP;
3113 
3114 		/* Section 4.2.2
3115 		 * If the address 0.0.0.0 or ::0 is provided, all
3116 		 * addresses of the peer except	the source address of the
3117 		 * packet MUST be deleted.
3118 		 */
3119 		if (af->is_any(&addr)) {
3120 			sctp_assoc_set_primary(asoc, asconf->transport);
3121 			sctp_assoc_del_nonprimary_peers(asoc,
3122 							asconf->transport);
3123 			return SCTP_ERROR_NO_ERROR;
3124 		}
3125 
3126 		/* If the address is not part of the association, the
3127 		 * ASCONF-ACK with Error Cause Indication Parameter
3128 		 * which including cause of Unresolvable Address should
3129 		 * be sent.
3130 		 */
3131 		peer = sctp_assoc_lookup_paddr(asoc, &addr);
3132 		if (!peer)
3133 			return SCTP_ERROR_DNS_FAILED;
3134 
3135 		sctp_assoc_rm_peer(asoc, peer);
3136 		break;
3137 	case SCTP_PARAM_SET_PRIMARY:
3138 		/* ADDIP Section 4.2.4
3139 		 * If the address 0.0.0.0 or ::0 is provided, the receiver
3140 		 * MAY mark the source address of the packet as its
3141 		 * primary.
3142 		 */
3143 		if (af->is_any(&addr))
3144 			memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));
3145 
3146 		if (security_sctp_bind_connect(asoc->ep->base.sk,
3147 					       SCTP_PARAM_SET_PRIMARY,
3148 					       (struct sockaddr *)&addr,
3149 					       af->sockaddr_len))
3150 			return SCTP_ERROR_REQ_REFUSED;
3151 
3152 		peer = sctp_assoc_lookup_paddr(asoc, &addr);
3153 		if (!peer)
3154 			return SCTP_ERROR_DNS_FAILED;
3155 
3156 		sctp_assoc_set_primary(asoc, peer);
3157 		break;
3158 	}
3159 
3160 	return SCTP_ERROR_NO_ERROR;
3161 }
3162 
3163 /* Verify the ASCONF packet before we process it. */
3164 bool sctp_verify_asconf(const struct sctp_association *asoc,
3165 			struct sctp_chunk *chunk, bool addr_param_needed,
3166 			struct sctp_paramhdr **errp)
3167 {
3168 	struct sctp_addip_chunk *addip;
3169 	bool addr_param_seen = false;
3170 	union sctp_params param;
3171 
3172 	addip = (struct sctp_addip_chunk *)chunk->chunk_hdr;
3173 	sctp_walk_params(param, addip, addip_hdr.params) {
3174 		size_t length = ntohs(param.p->length);
3175 
3176 		*errp = param.p;
3177 		switch (param.p->type) {
3178 		case SCTP_PARAM_ERR_CAUSE:
3179 			break;
3180 		case SCTP_PARAM_IPV4_ADDRESS:
3181 			if (length != sizeof(struct sctp_ipv4addr_param))
3182 				return false;
3183 			/* ensure there is only one addr param and it's in the
3184 			 * beginning of addip_hdr params, or we reject it.
3185 			 */
3186 			if (param.v != addip->addip_hdr.params)
3187 				return false;
3188 			addr_param_seen = true;
3189 			break;
3190 		case SCTP_PARAM_IPV6_ADDRESS:
3191 			if (length != sizeof(struct sctp_ipv6addr_param))
3192 				return false;
3193 			if (param.v != addip->addip_hdr.params)
3194 				return false;
3195 			addr_param_seen = true;
3196 			break;
3197 		case SCTP_PARAM_ADD_IP:
3198 		case SCTP_PARAM_DEL_IP:
3199 		case SCTP_PARAM_SET_PRIMARY:
3200 			/* In ASCONF chunks, these need to be first. */
3201 			if (addr_param_needed && !addr_param_seen)
3202 				return false;
3203 			length = ntohs(param.addip->param_hdr.length);
3204 			if (length < sizeof(struct sctp_addip_param) +
3205 				     sizeof(**errp))
3206 				return false;
3207 			break;
3208 		case SCTP_PARAM_SUCCESS_REPORT:
3209 		case SCTP_PARAM_ADAPTATION_LAYER_IND:
3210 			if (length != sizeof(struct sctp_addip_param))
3211 				return false;
3212 			break;
3213 		default:
3214 			/* This is unkown to us, reject! */
3215 			return false;
3216 		}
3217 	}
3218 
3219 	/* Remaining sanity checks. */
3220 	if (addr_param_needed && !addr_param_seen)
3221 		return false;
3222 	if (!addr_param_needed && addr_param_seen)
3223 		return false;
3224 	if (param.v != chunk->chunk_end)
3225 		return false;
3226 
3227 	return true;
3228 }
3229 
3230 /* Process an incoming ASCONF chunk with the next expected serial no. and
3231  * return an ASCONF_ACK chunk to be sent in response.
3232  */
3233 struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
3234 				       struct sctp_chunk *asconf)
3235 {
3236 	union sctp_addr_param *addr_param;
3237 	struct sctp_addip_chunk *addip;
3238 	struct sctp_chunk *asconf_ack;
3239 	bool all_param_pass = true;
3240 	struct sctp_addiphdr *hdr;
3241 	int length = 0, chunk_len;
3242 	union sctp_params param;
3243 	__be16 err_code;
3244 	__u32 serial;
3245 
3246 	addip = (struct sctp_addip_chunk *)asconf->chunk_hdr;
3247 	chunk_len = ntohs(asconf->chunk_hdr->length) -
3248 		    sizeof(struct sctp_chunkhdr);
3249 	hdr = (struct sctp_addiphdr *)asconf->skb->data;
3250 	serial = ntohl(hdr->serial);
3251 
3252 	/* Skip the addiphdr and store a pointer to address parameter.  */
3253 	length = sizeof(*hdr);
3254 	addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3255 	chunk_len -= length;
3256 
3257 	/* Skip the address parameter and store a pointer to the first
3258 	 * asconf parameter.
3259 	 */
3260 	length = ntohs(addr_param->p.length);
3261 	chunk_len -= length;
3262 
3263 	/* create an ASCONF_ACK chunk.
3264 	 * Based on the definitions of parameters, we know that the size of
3265 	 * ASCONF_ACK parameters are less than or equal to the fourfold of ASCONF
3266 	 * parameters.
3267 	 */
3268 	asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 4);
3269 	if (!asconf_ack)
3270 		goto done;
3271 
3272 	/* Process the TLVs contained within the ASCONF chunk. */
3273 	sctp_walk_params(param, addip, addip_hdr.params) {
3274 		/* Skip preceeding address parameters. */
3275 		if (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
3276 		    param.p->type == SCTP_PARAM_IPV6_ADDRESS)
3277 			continue;
3278 
3279 		err_code = sctp_process_asconf_param(asoc, asconf,
3280 						     param.addip);
3281 		/* ADDIP 4.1 A7)
3282 		 * If an error response is received for a TLV parameter,
3283 		 * all TLVs with no response before the failed TLV are
3284 		 * considered successful if not reported.  All TLVs after
3285 		 * the failed response are considered unsuccessful unless
3286 		 * a specific success indication is present for the parameter.
3287 		 */
3288 		if (err_code != SCTP_ERROR_NO_ERROR)
3289 			all_param_pass = false;
3290 		if (!all_param_pass)
3291 			sctp_add_asconf_response(asconf_ack, param.addip->crr_id,
3292 						 err_code, param.addip);
3293 
3294 		/* ADDIP 4.3 D11) When an endpoint receiving an ASCONF to add
3295 		 * an IP address sends an 'Out of Resource' in its response, it
3296 		 * MUST also fail any subsequent add or delete requests bundled
3297 		 * in the ASCONF.
3298 		 */
3299 		if (err_code == SCTP_ERROR_RSRC_LOW)
3300 			goto done;
3301 	}
3302 done:
3303 	asoc->peer.addip_serial++;
3304 
3305 	/* If we are sending a new ASCONF_ACK hold a reference to it in assoc
3306 	 * after freeing the reference to old asconf ack if any.
3307 	 */
3308 	if (asconf_ack) {
3309 		sctp_chunk_hold(asconf_ack);
3310 		list_add_tail(&asconf_ack->transmitted_list,
3311 			      &asoc->asconf_ack_list);
3312 	}
3313 
3314 	return asconf_ack;
3315 }
3316 
3317 /* Process a asconf parameter that is successfully acked. */
3318 static void sctp_asconf_param_success(struct sctp_association *asoc,
3319 				      struct sctp_addip_param *asconf_param)
3320 {
3321 	struct sctp_bind_addr *bp = &asoc->base.bind_addr;
3322 	union sctp_addr_param *addr_param;
3323 	struct sctp_sockaddr_entry *saddr;
3324 	struct sctp_transport *transport;
3325 	union sctp_addr	addr;
3326 	struct sctp_af *af;
3327 
3328 	addr_param = (void *)asconf_param + sizeof(*asconf_param);
3329 
3330 	/* We have checked the packet before, so we do not check again.	*/
3331 	af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3332 	af->from_addr_param(&addr, addr_param, htons(bp->port), 0);
3333 
3334 	switch (asconf_param->param_hdr.type) {
3335 	case SCTP_PARAM_ADD_IP:
3336 		/* This is always done in BH context with a socket lock
3337 		 * held, so the list can not change.
3338 		 */
3339 		local_bh_disable();
3340 		list_for_each_entry(saddr, &bp->address_list, list) {
3341 			if (sctp_cmp_addr_exact(&saddr->a, &addr))
3342 				saddr->state = SCTP_ADDR_SRC;
3343 		}
3344 		local_bh_enable();
3345 		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3346 				transports) {
3347 			sctp_transport_dst_release(transport);
3348 		}
3349 		break;
3350 	case SCTP_PARAM_DEL_IP:
3351 		local_bh_disable();
3352 		sctp_del_bind_addr(bp, &addr);
3353 		if (asoc->asconf_addr_del_pending != NULL &&
3354 		    sctp_cmp_addr_exact(asoc->asconf_addr_del_pending, &addr)) {
3355 			kfree(asoc->asconf_addr_del_pending);
3356 			asoc->asconf_addr_del_pending = NULL;
3357 		}
3358 		local_bh_enable();
3359 		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3360 				transports) {
3361 			sctp_transport_dst_release(transport);
3362 		}
3363 		break;
3364 	default:
3365 		break;
3366 	}
3367 }
3368 
3369 /* Get the corresponding ASCONF response error code from the ASCONF_ACK chunk
3370  * for the given asconf parameter.  If there is no response for this parameter,
3371  * return the error code based on the third argument 'no_err'.
3372  * ADDIP 4.1
3373  * A7) If an error response is received for a TLV parameter, all TLVs with no
3374  * response before the failed TLV are considered successful if not reported.
3375  * All TLVs after the failed response are considered unsuccessful unless a
3376  * specific success indication is present for the parameter.
3377  */
3378 static __be16 sctp_get_asconf_response(struct sctp_chunk *asconf_ack,
3379 				       struct sctp_addip_param *asconf_param,
3380 				       int no_err)
3381 {
3382 	struct sctp_addip_param	*asconf_ack_param;
3383 	struct sctp_errhdr *err_param;
3384 	int asconf_ack_len;
3385 	__be16 err_code;
3386 	int length;
3387 
3388 	if (no_err)
3389 		err_code = SCTP_ERROR_NO_ERROR;
3390 	else
3391 		err_code = SCTP_ERROR_REQ_REFUSED;
3392 
3393 	asconf_ack_len = ntohs(asconf_ack->chunk_hdr->length) -
3394 			 sizeof(struct sctp_chunkhdr);
3395 
3396 	/* Skip the addiphdr from the asconf_ack chunk and store a pointer to
3397 	 * the first asconf_ack parameter.
3398 	 */
3399 	length = sizeof(struct sctp_addiphdr);
3400 	asconf_ack_param = (struct sctp_addip_param *)(asconf_ack->skb->data +
3401 						       length);
3402 	asconf_ack_len -= length;
3403 
3404 	while (asconf_ack_len > 0) {
3405 		if (asconf_ack_param->crr_id == asconf_param->crr_id) {
3406 			switch (asconf_ack_param->param_hdr.type) {
3407 			case SCTP_PARAM_SUCCESS_REPORT:
3408 				return SCTP_ERROR_NO_ERROR;
3409 			case SCTP_PARAM_ERR_CAUSE:
3410 				length = sizeof(*asconf_ack_param);
3411 				err_param = (void *)asconf_ack_param + length;
3412 				asconf_ack_len -= length;
3413 				if (asconf_ack_len > 0)
3414 					return err_param->cause;
3415 				else
3416 					return SCTP_ERROR_INV_PARAM;
3417 				break;
3418 			default:
3419 				return SCTP_ERROR_INV_PARAM;
3420 			}
3421 		}
3422 
3423 		length = ntohs(asconf_ack_param->param_hdr.length);
3424 		asconf_ack_param = (void *)asconf_ack_param + length;
3425 		asconf_ack_len -= length;
3426 	}
3427 
3428 	return err_code;
3429 }
3430 
3431 /* Process an incoming ASCONF_ACK chunk against the cached last ASCONF chunk. */
3432 int sctp_process_asconf_ack(struct sctp_association *asoc,
3433 			    struct sctp_chunk *asconf_ack)
3434 {
3435 	struct sctp_chunk *asconf = asoc->addip_last_asconf;
3436 	struct sctp_addip_param *asconf_param;
3437 	__be16 err_code = SCTP_ERROR_NO_ERROR;
3438 	union sctp_addr_param *addr_param;
3439 	int asconf_len = asconf->skb->len;
3440 	int all_param_pass = 0;
3441 	int length = 0;
3442 	int no_err = 1;
3443 	int retval = 0;
3444 
3445 	/* Skip the chunkhdr and addiphdr from the last asconf sent and store
3446 	 * a pointer to address parameter.
3447 	 */
3448 	length = sizeof(struct sctp_addip_chunk);
3449 	addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3450 	asconf_len -= length;
3451 
3452 	/* Skip the address parameter in the last asconf sent and store a
3453 	 * pointer to the first asconf parameter.
3454 	 */
3455 	length = ntohs(addr_param->p.length);
3456 	asconf_param = (void *)addr_param + length;
3457 	asconf_len -= length;
3458 
3459 	/* ADDIP 4.1
3460 	 * A8) If there is no response(s) to specific TLV parameter(s), and no
3461 	 * failures are indicated, then all request(s) are considered
3462 	 * successful.
3463 	 */
3464 	if (asconf_ack->skb->len == sizeof(struct sctp_addiphdr))
3465 		all_param_pass = 1;
3466 
3467 	/* Process the TLVs contained in the last sent ASCONF chunk. */
3468 	while (asconf_len > 0) {
3469 		if (all_param_pass)
3470 			err_code = SCTP_ERROR_NO_ERROR;
3471 		else {
3472 			err_code = sctp_get_asconf_response(asconf_ack,
3473 							    asconf_param,
3474 							    no_err);
3475 			if (no_err && (SCTP_ERROR_NO_ERROR != err_code))
3476 				no_err = 0;
3477 		}
3478 
3479 		switch (err_code) {
3480 		case SCTP_ERROR_NO_ERROR:
3481 			sctp_asconf_param_success(asoc, asconf_param);
3482 			break;
3483 
3484 		case SCTP_ERROR_RSRC_LOW:
3485 			retval = 1;
3486 			break;
3487 
3488 		case SCTP_ERROR_UNKNOWN_PARAM:
3489 			/* Disable sending this type of asconf parameter in
3490 			 * future.
3491 			 */
3492 			asoc->peer.addip_disabled_mask |=
3493 				asconf_param->param_hdr.type;
3494 			break;
3495 
3496 		case SCTP_ERROR_REQ_REFUSED:
3497 		case SCTP_ERROR_DEL_LAST_IP:
3498 		case SCTP_ERROR_DEL_SRC_IP:
3499 		default:
3500 			 break;
3501 		}
3502 
3503 		/* Skip the processed asconf parameter and move to the next
3504 		 * one.
3505 		 */
3506 		length = ntohs(asconf_param->param_hdr.length);
3507 		asconf_param = (void *)asconf_param + length;
3508 		asconf_len -= length;
3509 	}
3510 
3511 	if (no_err && asoc->src_out_of_asoc_ok) {
3512 		asoc->src_out_of_asoc_ok = 0;
3513 		sctp_transport_immediate_rtx(asoc->peer.primary_path);
3514 	}
3515 
3516 	/* Free the cached last sent asconf chunk. */
3517 	list_del_init(&asconf->transmitted_list);
3518 	sctp_chunk_free(asconf);
3519 	asoc->addip_last_asconf = NULL;
3520 
3521 	return retval;
3522 }
3523 
3524 /* Make a FWD TSN chunk. */
3525 struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
3526 				    __u32 new_cum_tsn, size_t nstreams,
3527 				    struct sctp_fwdtsn_skip *skiplist)
3528 {
3529 	struct sctp_chunk *retval = NULL;
3530 	struct sctp_fwdtsn_hdr ftsn_hdr;
3531 	struct sctp_fwdtsn_skip skip;
3532 	size_t hint;
3533 	int i;
3534 
3535 	hint = (nstreams + 1) * sizeof(__u32);
3536 
3537 	retval = sctp_make_control(asoc, SCTP_CID_FWD_TSN, 0, hint, GFP_ATOMIC);
3538 
3539 	if (!retval)
3540 		return NULL;
3541 
3542 	ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
3543 	retval->subh.fwdtsn_hdr =
3544 		sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
3545 
3546 	for (i = 0; i < nstreams; i++) {
3547 		skip.stream = skiplist[i].stream;
3548 		skip.ssn = skiplist[i].ssn;
3549 		sctp_addto_chunk(retval, sizeof(skip), &skip);
3550 	}
3551 
3552 	return retval;
3553 }
3554 
3555 struct sctp_chunk *sctp_make_ifwdtsn(const struct sctp_association *asoc,
3556 				     __u32 new_cum_tsn, size_t nstreams,
3557 				     struct sctp_ifwdtsn_skip *skiplist)
3558 {
3559 	struct sctp_chunk *retval = NULL;
3560 	struct sctp_ifwdtsn_hdr ftsn_hdr;
3561 	size_t hint;
3562 
3563 	hint = (nstreams + 1) * sizeof(__u32);
3564 
3565 	retval = sctp_make_control(asoc, SCTP_CID_I_FWD_TSN, 0, hint,
3566 				   GFP_ATOMIC);
3567 	if (!retval)
3568 		return NULL;
3569 
3570 	ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
3571 	retval->subh.ifwdtsn_hdr =
3572 		sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
3573 
3574 	sctp_addto_chunk(retval, nstreams * sizeof(skiplist[0]), skiplist);
3575 
3576 	return retval;
3577 }
3578 
3579 /* RE-CONFIG 3.1 (RE-CONFIG chunk)
3580  *   0                   1                   2                   3
3581  *   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
3582  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3583  *  | Type = 130    |  Chunk Flags  |      Chunk Length             |
3584  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3585  *  \                                                               \
3586  *  /                  Re-configuration Parameter                   /
3587  *  \                                                               \
3588  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3589  *  \                                                               \
3590  *  /             Re-configuration Parameter (optional)             /
3591  *  \                                                               \
3592  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3593  */
3594 static struct sctp_chunk *sctp_make_reconf(const struct sctp_association *asoc,
3595 					   int length)
3596 {
3597 	struct sctp_reconf_chunk *reconf;
3598 	struct sctp_chunk *retval;
3599 
3600 	retval = sctp_make_control(asoc, SCTP_CID_RECONF, 0, length,
3601 				   GFP_ATOMIC);
3602 	if (!retval)
3603 		return NULL;
3604 
3605 	reconf = (struct sctp_reconf_chunk *)retval->chunk_hdr;
3606 	retval->param_hdr.v = reconf->params;
3607 
3608 	return retval;
3609 }
3610 
3611 /* RE-CONFIG 4.1 (STREAM OUT RESET)
3612  *   0                   1                   2                   3
3613  *   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
3614  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3615  *  |     Parameter Type = 13       | Parameter Length = 16 + 2 * N |
3616  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3617  *  |           Re-configuration Request Sequence Number            |
3618  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3619  *  |           Re-configuration Response Sequence Number           |
3620  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3621  *  |                Sender's Last Assigned TSN                     |
3622  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3623  *  |  Stream Number 1 (optional)   |    Stream Number 2 (optional) |
3624  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3625  *  /                            ......                             /
3626  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3627  *  |  Stream Number N-1 (optional) |    Stream Number N (optional) |
3628  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3629  *
3630  * RE-CONFIG 4.2 (STREAM IN RESET)
3631  *   0                   1                   2                   3
3632  *   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
3633  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3634  *  |     Parameter Type = 14       |  Parameter Length = 8 + 2 * N |
3635  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3636  *  |          Re-configuration Request Sequence Number             |
3637  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3638  *  |  Stream Number 1 (optional)   |    Stream Number 2 (optional) |
3639  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3640  *  /                            ......                             /
3641  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3642  *  |  Stream Number N-1 (optional) |    Stream Number N (optional) |
3643  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3644  */
3645 struct sctp_chunk *sctp_make_strreset_req(
3646 					const struct sctp_association *asoc,
3647 					__u16 stream_num, __be16 *stream_list,
3648 					bool out, bool in)
3649 {
3650 	__u16 stream_len = stream_num * sizeof(__u16);
3651 	struct sctp_strreset_outreq outreq;
3652 	struct sctp_strreset_inreq inreq;
3653 	struct sctp_chunk *retval;
3654 	__u16 outlen, inlen;
3655 
3656 	outlen = (sizeof(outreq) + stream_len) * out;
3657 	inlen = (sizeof(inreq) + stream_len) * in;
3658 
3659 	retval = sctp_make_reconf(asoc, outlen + inlen);
3660 	if (!retval)
3661 		return NULL;
3662 
3663 	if (outlen) {
3664 		outreq.param_hdr.type = SCTP_PARAM_RESET_OUT_REQUEST;
3665 		outreq.param_hdr.length = htons(outlen);
3666 		outreq.request_seq = htonl(asoc->strreset_outseq);
3667 		outreq.response_seq = htonl(asoc->strreset_inseq - 1);
3668 		outreq.send_reset_at_tsn = htonl(asoc->next_tsn - 1);
3669 
3670 		sctp_addto_chunk(retval, sizeof(outreq), &outreq);
3671 
3672 		if (stream_len)
3673 			sctp_addto_chunk(retval, stream_len, stream_list);
3674 	}
3675 
3676 	if (inlen) {
3677 		inreq.param_hdr.type = SCTP_PARAM_RESET_IN_REQUEST;
3678 		inreq.param_hdr.length = htons(inlen);
3679 		inreq.request_seq = htonl(asoc->strreset_outseq + out);
3680 
3681 		sctp_addto_chunk(retval, sizeof(inreq), &inreq);
3682 
3683 		if (stream_len)
3684 			sctp_addto_chunk(retval, stream_len, stream_list);
3685 	}
3686 
3687 	return retval;
3688 }
3689 
3690 /* RE-CONFIG 4.3 (SSN/TSN RESET ALL)
3691  *   0                   1                   2                   3
3692  *   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
3693  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3694  *  |     Parameter Type = 15       |      Parameter Length = 8     |
3695  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3696  *  |         Re-configuration Request Sequence Number              |
3697  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3698  */
3699 struct sctp_chunk *sctp_make_strreset_tsnreq(
3700 					const struct sctp_association *asoc)
3701 {
3702 	struct sctp_strreset_tsnreq tsnreq;
3703 	__u16 length = sizeof(tsnreq);
3704 	struct sctp_chunk *retval;
3705 
3706 	retval = sctp_make_reconf(asoc, length);
3707 	if (!retval)
3708 		return NULL;
3709 
3710 	tsnreq.param_hdr.type = SCTP_PARAM_RESET_TSN_REQUEST;
3711 	tsnreq.param_hdr.length = htons(length);
3712 	tsnreq.request_seq = htonl(asoc->strreset_outseq);
3713 
3714 	sctp_addto_chunk(retval, sizeof(tsnreq), &tsnreq);
3715 
3716 	return retval;
3717 }
3718 
3719 /* RE-CONFIG 4.5/4.6 (ADD STREAM)
3720  *   0                   1                   2                   3
3721  *   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
3722  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3723  *  |     Parameter Type = 17       |      Parameter Length = 12    |
3724  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3725  *  |          Re-configuration Request Sequence Number             |
3726  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3727  *  |      Number of new streams    |         Reserved              |
3728  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3729  */
3730 struct sctp_chunk *sctp_make_strreset_addstrm(
3731 					const struct sctp_association *asoc,
3732 					__u16 out, __u16 in)
3733 {
3734 	struct sctp_strreset_addstrm addstrm;
3735 	__u16 size = sizeof(addstrm);
3736 	struct sctp_chunk *retval;
3737 
3738 	retval = sctp_make_reconf(asoc, (!!out + !!in) * size);
3739 	if (!retval)
3740 		return NULL;
3741 
3742 	if (out) {
3743 		addstrm.param_hdr.type = SCTP_PARAM_RESET_ADD_OUT_STREAMS;
3744 		addstrm.param_hdr.length = htons(size);
3745 		addstrm.number_of_streams = htons(out);
3746 		addstrm.request_seq = htonl(asoc->strreset_outseq);
3747 		addstrm.reserved = 0;
3748 
3749 		sctp_addto_chunk(retval, size, &addstrm);
3750 	}
3751 
3752 	if (in) {
3753 		addstrm.param_hdr.type = SCTP_PARAM_RESET_ADD_IN_STREAMS;
3754 		addstrm.param_hdr.length = htons(size);
3755 		addstrm.number_of_streams = htons(in);
3756 		addstrm.request_seq = htonl(asoc->strreset_outseq + !!out);
3757 		addstrm.reserved = 0;
3758 
3759 		sctp_addto_chunk(retval, size, &addstrm);
3760 	}
3761 
3762 	return retval;
3763 }
3764 
3765 /* RE-CONFIG 4.4 (RESP)
3766  *   0                   1                   2                   3
3767  *   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
3768  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3769  *  |     Parameter Type = 16       |      Parameter Length         |
3770  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3771  *  |         Re-configuration Response Sequence Number             |
3772  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3773  *  |                            Result                             |
3774  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3775  */
3776 struct sctp_chunk *sctp_make_strreset_resp(const struct sctp_association *asoc,
3777 					   __u32 result, __u32 sn)
3778 {
3779 	struct sctp_strreset_resp resp;
3780 	__u16 length = sizeof(resp);
3781 	struct sctp_chunk *retval;
3782 
3783 	retval = sctp_make_reconf(asoc, length);
3784 	if (!retval)
3785 		return NULL;
3786 
3787 	resp.param_hdr.type = SCTP_PARAM_RESET_RESPONSE;
3788 	resp.param_hdr.length = htons(length);
3789 	resp.response_seq = htonl(sn);
3790 	resp.result = htonl(result);
3791 
3792 	sctp_addto_chunk(retval, sizeof(resp), &resp);
3793 
3794 	return retval;
3795 }
3796 
3797 /* RE-CONFIG 4.4 OPTIONAL (TSNRESP)
3798  *   0                   1                   2                   3
3799  *   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
3800  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3801  *  |     Parameter Type = 16       |      Parameter Length         |
3802  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3803  *  |         Re-configuration Response Sequence Number             |
3804  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3805  *  |                            Result                             |
3806  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3807  *  |                   Sender's Next TSN (optional)                |
3808  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3809  *  |                  Receiver's Next TSN (optional)               |
3810  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3811  */
3812 struct sctp_chunk *sctp_make_strreset_tsnresp(struct sctp_association *asoc,
3813 					      __u32 result, __u32 sn,
3814 					      __u32 sender_tsn,
3815 					      __u32 receiver_tsn)
3816 {
3817 	struct sctp_strreset_resptsn tsnresp;
3818 	__u16 length = sizeof(tsnresp);
3819 	struct sctp_chunk *retval;
3820 
3821 	retval = sctp_make_reconf(asoc, length);
3822 	if (!retval)
3823 		return NULL;
3824 
3825 	tsnresp.param_hdr.type = SCTP_PARAM_RESET_RESPONSE;
3826 	tsnresp.param_hdr.length = htons(length);
3827 
3828 	tsnresp.response_seq = htonl(sn);
3829 	tsnresp.result = htonl(result);
3830 	tsnresp.senders_next_tsn = htonl(sender_tsn);
3831 	tsnresp.receivers_next_tsn = htonl(receiver_tsn);
3832 
3833 	sctp_addto_chunk(retval, sizeof(tsnresp), &tsnresp);
3834 
3835 	return retval;
3836 }
3837 
3838 bool sctp_verify_reconf(const struct sctp_association *asoc,
3839 			struct sctp_chunk *chunk,
3840 			struct sctp_paramhdr **errp)
3841 {
3842 	struct sctp_reconf_chunk *hdr;
3843 	union sctp_params param;
3844 	__be16 last = 0;
3845 	__u16 cnt = 0;
3846 
3847 	hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
3848 	sctp_walk_params(param, hdr, params) {
3849 		__u16 length = ntohs(param.p->length);
3850 
3851 		*errp = param.p;
3852 		if (cnt++ > 2)
3853 			return false;
3854 		switch (param.p->type) {
3855 		case SCTP_PARAM_RESET_OUT_REQUEST:
3856 			if (length < sizeof(struct sctp_strreset_outreq) ||
3857 			    (last && last != SCTP_PARAM_RESET_RESPONSE &&
3858 			     last != SCTP_PARAM_RESET_IN_REQUEST))
3859 				return false;
3860 			break;
3861 		case SCTP_PARAM_RESET_IN_REQUEST:
3862 			if (length < sizeof(struct sctp_strreset_inreq) ||
3863 			    (last && last != SCTP_PARAM_RESET_OUT_REQUEST))
3864 				return false;
3865 			break;
3866 		case SCTP_PARAM_RESET_RESPONSE:
3867 			if ((length != sizeof(struct sctp_strreset_resp) &&
3868 			     length != sizeof(struct sctp_strreset_resptsn)) ||
3869 			    (last && last != SCTP_PARAM_RESET_RESPONSE &&
3870 			     last != SCTP_PARAM_RESET_OUT_REQUEST))
3871 				return false;
3872 			break;
3873 		case SCTP_PARAM_RESET_TSN_REQUEST:
3874 			if (length !=
3875 			    sizeof(struct sctp_strreset_tsnreq) || last)
3876 				return false;
3877 			break;
3878 		case SCTP_PARAM_RESET_ADD_IN_STREAMS:
3879 			if (length != sizeof(struct sctp_strreset_addstrm) ||
3880 			    (last && last != SCTP_PARAM_RESET_ADD_OUT_STREAMS))
3881 				return false;
3882 			break;
3883 		case SCTP_PARAM_RESET_ADD_OUT_STREAMS:
3884 			if (length != sizeof(struct sctp_strreset_addstrm) ||
3885 			    (last && last != SCTP_PARAM_RESET_ADD_IN_STREAMS))
3886 				return false;
3887 			break;
3888 		default:
3889 			return false;
3890 		}
3891 
3892 		last = param.p->type;
3893 	}
3894 
3895 	return true;
3896 }
3897