xref: /openbmc/linux/net/sctp/sm_make_chunk.c (revision 68198dca)
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 static void  *sctp_addto_chunk_fixed(struct sctp_chunk *, int len,
85 				     const void *data);
86 
87 /* Control chunk destructor */
88 static void sctp_control_release_owner(struct sk_buff *skb)
89 {
90 	/*TODO: do memory release */
91 }
92 
93 static void sctp_control_set_owner_w(struct sctp_chunk *chunk)
94 {
95 	struct sctp_association *asoc = chunk->asoc;
96 	struct sk_buff *skb = chunk->skb;
97 
98 	/* TODO: properly account for control chunks.
99 	 * To do it right we'll need:
100 	 *  1) endpoint if association isn't known.
101 	 *  2) proper memory accounting.
102 	 *
103 	 *  For now don't do anything for now.
104 	 */
105 	skb->sk = asoc ? asoc->base.sk : NULL;
106 	skb->destructor = sctp_control_release_owner;
107 }
108 
109 /* What was the inbound interface for this chunk? */
110 int sctp_chunk_iif(const struct sctp_chunk *chunk)
111 {
112 	struct sk_buff *skb = chunk->skb;
113 
114 	return SCTP_INPUT_CB(skb)->af->skb_iif(skb);
115 }
116 
117 /* RFC 2960 3.3.2 Initiation (INIT) (1)
118  *
119  * Note 2: The ECN capable field is reserved for future use of
120  * Explicit Congestion Notification.
121  */
122 static const struct sctp_paramhdr ecap_param = {
123 	SCTP_PARAM_ECN_CAPABLE,
124 	cpu_to_be16(sizeof(struct sctp_paramhdr)),
125 };
126 static const struct sctp_paramhdr prsctp_param = {
127 	SCTP_PARAM_FWD_TSN_SUPPORT,
128 	cpu_to_be16(sizeof(struct sctp_paramhdr)),
129 };
130 
131 /* A helper to initialize an op error inside a
132  * provided chunk, as most cause codes will be embedded inside an
133  * abort chunk.
134  */
135 void sctp_init_cause(struct sctp_chunk *chunk, __be16 cause_code,
136 		     size_t paylen)
137 {
138 	struct sctp_errhdr err;
139 	__u16 len;
140 
141 	/* Cause code constants are now defined in network order.  */
142 	err.cause = cause_code;
143 	len = sizeof(err) + paylen;
144 	err.length  = htons(len);
145 	chunk->subh.err_hdr = sctp_addto_chunk(chunk, sizeof(err), &err);
146 }
147 
148 /* A helper to initialize an op error inside a
149  * provided chunk, as most cause codes will be embedded inside an
150  * abort chunk.  Differs from sctp_init_cause in that it won't oops
151  * if there isn't enough space in the op error chunk
152  */
153 static int sctp_init_cause_fixed(struct sctp_chunk *chunk, __be16 cause_code,
154 				 size_t paylen)
155 {
156 	struct sctp_errhdr err;
157 	__u16 len;
158 
159 	/* Cause code constants are now defined in network order.  */
160 	err.cause = cause_code;
161 	len = sizeof(err) + paylen;
162 	err.length  = htons(len);
163 
164 	if (skb_tailroom(chunk->skb) < len)
165 		return -ENOSPC;
166 
167 	chunk->subh.err_hdr = sctp_addto_chunk_fixed(chunk, sizeof(err), &err);
168 
169 	return 0;
170 }
171 /* 3.3.2 Initiation (INIT) (1)
172  *
173  * This chunk is used to initiate a SCTP association between two
174  * endpoints. The format of the INIT chunk is shown below:
175  *
176  *     0                   1                   2                   3
177  *     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
178  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
179  *    |   Type = 1    |  Chunk Flags  |      Chunk Length             |
180  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
181  *    |                         Initiate Tag                          |
182  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
183  *    |           Advertised Receiver Window Credit (a_rwnd)          |
184  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
185  *    |  Number of Outbound Streams   |  Number of Inbound Streams    |
186  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
187  *    |                          Initial TSN                          |
188  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
189  *    \                                                               \
190  *    /              Optional/Variable-Length Parameters              /
191  *    \                                                               \
192  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
193  *
194  *
195  * The INIT chunk contains the following parameters. Unless otherwise
196  * noted, each parameter MUST only be included once in the INIT chunk.
197  *
198  * Fixed Parameters                     Status
199  * ----------------------------------------------
200  * Initiate Tag                        Mandatory
201  * Advertised Receiver Window Credit   Mandatory
202  * Number of Outbound Streams          Mandatory
203  * Number of Inbound Streams           Mandatory
204  * Initial TSN                         Mandatory
205  *
206  * Variable Parameters                  Status     Type Value
207  * -------------------------------------------------------------
208  * IPv4 Address (Note 1)               Optional    5
209  * IPv6 Address (Note 1)               Optional    6
210  * Cookie Preservative                 Optional    9
211  * Reserved for ECN Capable (Note 2)   Optional    32768 (0x8000)
212  * Host Name Address (Note 3)          Optional    11
213  * Supported Address Types (Note 4)    Optional    12
214  */
215 struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc,
216 				  const struct sctp_bind_addr *bp,
217 				  gfp_t gfp, int vparam_len)
218 {
219 	struct net *net = sock_net(asoc->base.sk);
220 	struct sctp_supported_ext_param ext_param;
221 	struct sctp_adaptation_ind_param aiparam;
222 	struct sctp_paramhdr *auth_chunks = NULL;
223 	struct sctp_paramhdr *auth_hmacs = NULL;
224 	struct sctp_supported_addrs_param sat;
225 	struct sctp_endpoint *ep = asoc->ep;
226 	struct sctp_chunk *retval = NULL;
227 	int num_types, addrs_len = 0;
228 	struct sctp_inithdr init;
229 	union sctp_params addrs;
230 	struct sctp_sock *sp;
231 	__u8 extensions[4];
232 	size_t chunksize;
233 	__be16 types[2];
234 	int num_ext = 0;
235 
236 	/* RFC 2960 3.3.2 Initiation (INIT) (1)
237 	 *
238 	 * Note 1: The INIT chunks can contain multiple addresses that
239 	 * can be IPv4 and/or IPv6 in any combination.
240 	 */
241 
242 	/* Convert the provided bind address list to raw format. */
243 	addrs = sctp_bind_addrs_to_raw(bp, &addrs_len, gfp);
244 
245 	init.init_tag		   = htonl(asoc->c.my_vtag);
246 	init.a_rwnd		   = htonl(asoc->rwnd);
247 	init.num_outbound_streams  = htons(asoc->c.sinit_num_ostreams);
248 	init.num_inbound_streams   = htons(asoc->c.sinit_max_instreams);
249 	init.initial_tsn	   = htonl(asoc->c.initial_tsn);
250 
251 	/* How many address types are needed? */
252 	sp = sctp_sk(asoc->base.sk);
253 	num_types = sp->pf->supported_addrs(sp, types);
254 
255 	chunksize = sizeof(init) + addrs_len;
256 	chunksize += SCTP_PAD4(SCTP_SAT_LEN(num_types));
257 	chunksize += sizeof(ecap_param);
258 
259 	if (asoc->prsctp_enable)
260 		chunksize += sizeof(prsctp_param);
261 
262 	/* ADDIP: Section 4.2.7:
263 	 *  An implementation supporting this extension [ADDIP] MUST list
264 	 *  the ASCONF,the ASCONF-ACK, and the AUTH  chunks in its INIT and
265 	 *  INIT-ACK parameters.
266 	 */
267 	if (net->sctp.addip_enable) {
268 		extensions[num_ext] = SCTP_CID_ASCONF;
269 		extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
270 		num_ext += 2;
271 	}
272 
273 	if (asoc->reconf_enable) {
274 		extensions[num_ext] = SCTP_CID_RECONF;
275 		num_ext += 1;
276 	}
277 
278 	if (sp->adaptation_ind)
279 		chunksize += sizeof(aiparam);
280 
281 	chunksize += vparam_len;
282 
283 	/* Account for AUTH related parameters */
284 	if (ep->auth_enable) {
285 		/* Add random parameter length*/
286 		chunksize += sizeof(asoc->c.auth_random);
287 
288 		/* Add HMACS parameter length if any were defined */
289 		auth_hmacs = (struct sctp_paramhdr *)asoc->c.auth_hmacs;
290 		if (auth_hmacs->length)
291 			chunksize += SCTP_PAD4(ntohs(auth_hmacs->length));
292 		else
293 			auth_hmacs = NULL;
294 
295 		/* Add CHUNKS parameter length */
296 		auth_chunks = (struct sctp_paramhdr *)asoc->c.auth_chunks;
297 		if (auth_chunks->length)
298 			chunksize += SCTP_PAD4(ntohs(auth_chunks->length));
299 		else
300 			auth_chunks = NULL;
301 
302 		extensions[num_ext] = SCTP_CID_AUTH;
303 		num_ext += 1;
304 	}
305 
306 	/* If we have any extensions to report, account for that */
307 	if (num_ext)
308 		chunksize += SCTP_PAD4(sizeof(ext_param) + num_ext);
309 
310 	/* RFC 2960 3.3.2 Initiation (INIT) (1)
311 	 *
312 	 * Note 3: An INIT chunk MUST NOT contain more than one Host
313 	 * Name address parameter. Moreover, the sender of the INIT
314 	 * MUST NOT combine any other address types with the Host Name
315 	 * address in the INIT. The receiver of INIT MUST ignore any
316 	 * other address types if the Host Name address parameter is
317 	 * present in the received INIT chunk.
318 	 *
319 	 * PLEASE DO NOT FIXME [This version does not support Host Name.]
320 	 */
321 
322 	retval = sctp_make_control(asoc, SCTP_CID_INIT, 0, chunksize, gfp);
323 	if (!retval)
324 		goto nodata;
325 
326 	retval->subh.init_hdr =
327 		sctp_addto_chunk(retval, sizeof(init), &init);
328 	retval->param_hdr.v =
329 		sctp_addto_chunk(retval, addrs_len, addrs.v);
330 
331 	/* RFC 2960 3.3.2 Initiation (INIT) (1)
332 	 *
333 	 * Note 4: This parameter, when present, specifies all the
334 	 * address types the sending endpoint can support. The absence
335 	 * of this parameter indicates that the sending endpoint can
336 	 * support any address type.
337 	 */
338 	sat.param_hdr.type = SCTP_PARAM_SUPPORTED_ADDRESS_TYPES;
339 	sat.param_hdr.length = htons(SCTP_SAT_LEN(num_types));
340 	sctp_addto_chunk(retval, sizeof(sat), &sat);
341 	sctp_addto_chunk(retval, num_types * sizeof(__u16), &types);
342 
343 	sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
344 
345 	/* Add the supported extensions parameter.  Be nice and add this
346 	 * fist before addiding the parameters for the extensions themselves
347 	 */
348 	if (num_ext) {
349 		ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
350 		ext_param.param_hdr.length = htons(sizeof(ext_param) + num_ext);
351 		sctp_addto_chunk(retval, sizeof(ext_param), &ext_param);
352 		sctp_addto_param(retval, num_ext, extensions);
353 	}
354 
355 	if (asoc->prsctp_enable)
356 		sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
357 
358 	if (sp->adaptation_ind) {
359 		aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
360 		aiparam.param_hdr.length = htons(sizeof(aiparam));
361 		aiparam.adaptation_ind = htonl(sp->adaptation_ind);
362 		sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
363 	}
364 
365 	/* Add SCTP-AUTH chunks to the parameter list */
366 	if (ep->auth_enable) {
367 		sctp_addto_chunk(retval, sizeof(asoc->c.auth_random),
368 				 asoc->c.auth_random);
369 		if (auth_hmacs)
370 			sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
371 					auth_hmacs);
372 		if (auth_chunks)
373 			sctp_addto_chunk(retval, ntohs(auth_chunks->length),
374 					auth_chunks);
375 	}
376 nodata:
377 	kfree(addrs.v);
378 	return retval;
379 }
380 
381 struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc,
382 				      const struct sctp_chunk *chunk,
383 				      gfp_t gfp, int unkparam_len)
384 {
385 	struct sctp_supported_ext_param ext_param;
386 	struct sctp_adaptation_ind_param aiparam;
387 	struct sctp_paramhdr *auth_chunks = NULL;
388 	struct sctp_paramhdr *auth_random = NULL;
389 	struct sctp_paramhdr *auth_hmacs = NULL;
390 	struct sctp_chunk *retval = NULL;
391 	struct sctp_cookie_param *cookie;
392 	struct sctp_inithdr initack;
393 	union sctp_params addrs;
394 	struct sctp_sock *sp;
395 	__u8 extensions[4];
396 	size_t chunksize;
397 	int num_ext = 0;
398 	int cookie_len;
399 	int addrs_len;
400 
401 	/* Note: there may be no addresses to embed. */
402 	addrs = sctp_bind_addrs_to_raw(&asoc->base.bind_addr, &addrs_len, gfp);
403 
404 	initack.init_tag	        = htonl(asoc->c.my_vtag);
405 	initack.a_rwnd			= htonl(asoc->rwnd);
406 	initack.num_outbound_streams	= htons(asoc->c.sinit_num_ostreams);
407 	initack.num_inbound_streams	= htons(asoc->c.sinit_max_instreams);
408 	initack.initial_tsn		= htonl(asoc->c.initial_tsn);
409 
410 	/* FIXME:  We really ought to build the cookie right
411 	 * into the packet instead of allocating more fresh memory.
412 	 */
413 	cookie = sctp_pack_cookie(asoc->ep, asoc, chunk, &cookie_len,
414 				  addrs.v, addrs_len);
415 	if (!cookie)
416 		goto nomem_cookie;
417 
418 	/* Calculate the total size of allocation, include the reserved
419 	 * space for reporting unknown parameters if it is specified.
420 	 */
421 	sp = sctp_sk(asoc->base.sk);
422 	chunksize = sizeof(initack) + addrs_len + cookie_len + unkparam_len;
423 
424 	/* Tell peer that we'll do ECN only if peer advertised such cap.  */
425 	if (asoc->peer.ecn_capable)
426 		chunksize += sizeof(ecap_param);
427 
428 	if (asoc->peer.prsctp_capable)
429 		chunksize += sizeof(prsctp_param);
430 
431 	if (asoc->peer.asconf_capable) {
432 		extensions[num_ext] = SCTP_CID_ASCONF;
433 		extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
434 		num_ext += 2;
435 	}
436 
437 	if (asoc->peer.reconf_capable) {
438 		extensions[num_ext] = SCTP_CID_RECONF;
439 		num_ext += 1;
440 	}
441 
442 	if (sp->adaptation_ind)
443 		chunksize += sizeof(aiparam);
444 
445 	if (asoc->peer.auth_capable) {
446 		auth_random = (struct sctp_paramhdr *)asoc->c.auth_random;
447 		chunksize += ntohs(auth_random->length);
448 
449 		auth_hmacs = (struct sctp_paramhdr *)asoc->c.auth_hmacs;
450 		if (auth_hmacs->length)
451 			chunksize += SCTP_PAD4(ntohs(auth_hmacs->length));
452 		else
453 			auth_hmacs = NULL;
454 
455 		auth_chunks = (struct sctp_paramhdr *)asoc->c.auth_chunks;
456 		if (auth_chunks->length)
457 			chunksize += SCTP_PAD4(ntohs(auth_chunks->length));
458 		else
459 			auth_chunks = NULL;
460 
461 		extensions[num_ext] = SCTP_CID_AUTH;
462 		num_ext += 1;
463 	}
464 
465 	if (num_ext)
466 		chunksize += SCTP_PAD4(sizeof(ext_param) + num_ext);
467 
468 	/* Now allocate and fill out the chunk.  */
469 	retval = sctp_make_control(asoc, SCTP_CID_INIT_ACK, 0, chunksize, gfp);
470 	if (!retval)
471 		goto nomem_chunk;
472 
473 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
474 	 *
475 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
476 	 * HEARTBEAT ACK, * etc.) to the same destination transport
477 	 * address from which it received the DATA or control chunk
478 	 * to which it is replying.
479 	 *
480 	 * [INIT ACK back to where the INIT came from.]
481 	 */
482 	retval->transport = chunk->transport;
483 
484 	retval->subh.init_hdr =
485 		sctp_addto_chunk(retval, sizeof(initack), &initack);
486 	retval->param_hdr.v = sctp_addto_chunk(retval, addrs_len, addrs.v);
487 	sctp_addto_chunk(retval, cookie_len, cookie);
488 	if (asoc->peer.ecn_capable)
489 		sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
490 	if (num_ext) {
491 		ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
492 		ext_param.param_hdr.length = htons(sizeof(ext_param) + num_ext);
493 		sctp_addto_chunk(retval, sizeof(ext_param), &ext_param);
494 		sctp_addto_param(retval, num_ext, extensions);
495 	}
496 	if (asoc->peer.prsctp_capable)
497 		sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
498 
499 	if (sp->adaptation_ind) {
500 		aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
501 		aiparam.param_hdr.length = htons(sizeof(aiparam));
502 		aiparam.adaptation_ind = htonl(sp->adaptation_ind);
503 		sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
504 	}
505 
506 	if (asoc->peer.auth_capable) {
507 		sctp_addto_chunk(retval, ntohs(auth_random->length),
508 				 auth_random);
509 		if (auth_hmacs)
510 			sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
511 					auth_hmacs);
512 		if (auth_chunks)
513 			sctp_addto_chunk(retval, ntohs(auth_chunks->length),
514 					auth_chunks);
515 	}
516 
517 	/* We need to remove the const qualifier at this point.  */
518 	retval->asoc = (struct sctp_association *) asoc;
519 
520 nomem_chunk:
521 	kfree(cookie);
522 nomem_cookie:
523 	kfree(addrs.v);
524 	return retval;
525 }
526 
527 /* 3.3.11 Cookie Echo (COOKIE ECHO) (10):
528  *
529  * This chunk is used only during the initialization of an association.
530  * It is sent by the initiator of an association to its peer to complete
531  * the initialization process. This chunk MUST precede any DATA chunk
532  * sent within the association, but MAY be bundled with one or more DATA
533  * chunks in the same packet.
534  *
535  *      0                   1                   2                   3
536  *      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
537  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
538  *     |   Type = 10   |Chunk  Flags   |         Length                |
539  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
540  *     /                     Cookie                                    /
541  *     \                                                               \
542  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
543  *
544  * Chunk Flags: 8 bit
545  *
546  *   Set to zero on transmit and ignored on receipt.
547  *
548  * Length: 16 bits (unsigned integer)
549  *
550  *   Set to the size of the chunk in bytes, including the 4 bytes of
551  *   the chunk header and the size of the Cookie.
552  *
553  * Cookie: variable size
554  *
555  *   This field must contain the exact cookie received in the
556  *   State Cookie parameter from the previous INIT ACK.
557  *
558  *   An implementation SHOULD make the cookie as small as possible
559  *   to insure interoperability.
560  */
561 struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *asoc,
562 					 const struct sctp_chunk *chunk)
563 {
564 	struct sctp_chunk *retval;
565 	int cookie_len;
566 	void *cookie;
567 
568 	cookie = asoc->peer.cookie;
569 	cookie_len = asoc->peer.cookie_len;
570 
571 	/* Build a cookie echo chunk.  */
572 	retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ECHO, 0,
573 				   cookie_len, GFP_ATOMIC);
574 	if (!retval)
575 		goto nodata;
576 	retval->subh.cookie_hdr =
577 		sctp_addto_chunk(retval, cookie_len, cookie);
578 
579 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
580 	 *
581 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
582 	 * HEARTBEAT ACK, * etc.) to the same destination transport
583 	 * address from which it * received the DATA or control chunk
584 	 * to which it is replying.
585 	 *
586 	 * [COOKIE ECHO back to where the INIT ACK came from.]
587 	 */
588 	if (chunk)
589 		retval->transport = chunk->transport;
590 
591 nodata:
592 	return retval;
593 }
594 
595 /* 3.3.12 Cookie Acknowledgement (COOKIE ACK) (11):
596  *
597  * This chunk is used only during the initialization of an
598  * association.  It is used to acknowledge the receipt of a COOKIE
599  * ECHO chunk.  This chunk MUST precede any DATA or SACK chunk sent
600  * within the association, but MAY be bundled with one or more DATA
601  * chunks or SACK chunk in the same SCTP packet.
602  *
603  *      0                   1                   2                   3
604  *      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
605  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
606  *     |   Type = 11   |Chunk  Flags   |     Length = 4                |
607  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
608  *
609  * Chunk Flags: 8 bits
610  *
611  *   Set to zero on transmit and ignored on receipt.
612  */
613 struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *asoc,
614 					const struct sctp_chunk *chunk)
615 {
616 	struct sctp_chunk *retval;
617 
618 	retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ACK, 0, 0, GFP_ATOMIC);
619 
620 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
621 	 *
622 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
623 	 * HEARTBEAT ACK, * etc.) to the same destination transport
624 	 * address from which it * received the DATA or control chunk
625 	 * to which it is replying.
626 	 *
627 	 * [COOKIE ACK back to where the COOKIE ECHO came from.]
628 	 */
629 	if (retval && chunk)
630 		retval->transport = chunk->transport;
631 
632 	return retval;
633 }
634 
635 /*
636  *  Appendix A: Explicit Congestion Notification:
637  *  CWR:
638  *
639  *  RFC 2481 details a specific bit for a sender to send in the header of
640  *  its next outbound TCP segment to indicate to its peer that it has
641  *  reduced its congestion window.  This is termed the CWR bit.  For
642  *  SCTP the same indication is made by including the CWR chunk.
643  *  This chunk contains one data element, i.e. the TSN number that
644  *  was sent in the ECNE chunk.  This element represents the lowest
645  *  TSN number in the datagram that was originally marked with the
646  *  CE bit.
647  *
648  *     0                   1                   2                   3
649  *     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
650  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
651  *    | Chunk Type=13 | Flags=00000000|    Chunk Length = 8           |
652  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
653  *    |                      Lowest TSN Number                        |
654  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
655  *
656  *     Note: The CWR is considered a Control chunk.
657  */
658 struct sctp_chunk *sctp_make_cwr(const struct sctp_association *asoc,
659 				 const __u32 lowest_tsn,
660 				 const struct sctp_chunk *chunk)
661 {
662 	struct sctp_chunk *retval;
663 	struct sctp_cwrhdr cwr;
664 
665 	cwr.lowest_tsn = htonl(lowest_tsn);
666 	retval = sctp_make_control(asoc, SCTP_CID_ECN_CWR, 0,
667 				   sizeof(cwr), GFP_ATOMIC);
668 
669 	if (!retval)
670 		goto nodata;
671 
672 	retval->subh.ecn_cwr_hdr =
673 		sctp_addto_chunk(retval, sizeof(cwr), &cwr);
674 
675 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
676 	 *
677 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
678 	 * HEARTBEAT ACK, * etc.) to the same destination transport
679 	 * address from which it * received the DATA or control chunk
680 	 * to which it is replying.
681 	 *
682 	 * [Report a reduced congestion window back to where the ECNE
683 	 * came from.]
684 	 */
685 	if (chunk)
686 		retval->transport = chunk->transport;
687 
688 nodata:
689 	return retval;
690 }
691 
692 /* Make an ECNE chunk.  This is a congestion experienced report.  */
693 struct sctp_chunk *sctp_make_ecne(const struct sctp_association *asoc,
694 				  const __u32 lowest_tsn)
695 {
696 	struct sctp_chunk *retval;
697 	struct sctp_ecnehdr ecne;
698 
699 	ecne.lowest_tsn = htonl(lowest_tsn);
700 	retval = sctp_make_control(asoc, SCTP_CID_ECN_ECNE, 0,
701 				   sizeof(ecne), GFP_ATOMIC);
702 	if (!retval)
703 		goto nodata;
704 	retval->subh.ecne_hdr =
705 		sctp_addto_chunk(retval, sizeof(ecne), &ecne);
706 
707 nodata:
708 	return retval;
709 }
710 
711 /* Make a DATA chunk for the given association from the provided
712  * parameters.  However, do not populate the data payload.
713  */
714 struct sctp_chunk *sctp_make_datafrag_empty(struct sctp_association *asoc,
715 					    const struct sctp_sndrcvinfo *sinfo,
716 					    int data_len, __u8 flags, __u16 ssn,
717 					    gfp_t gfp)
718 {
719 	struct sctp_chunk *retval;
720 	struct sctp_datahdr dp;
721 	int chunk_len;
722 
723 	/* We assign the TSN as LATE as possible, not here when
724 	 * creating the chunk.
725 	 */
726 	dp.tsn = 0;
727 	dp.stream = htons(sinfo->sinfo_stream);
728 	dp.ppid   = sinfo->sinfo_ppid;
729 
730 	/* Set the flags for an unordered send.  */
731 	if (sinfo->sinfo_flags & SCTP_UNORDERED) {
732 		flags |= SCTP_DATA_UNORDERED;
733 		dp.ssn = 0;
734 	} else
735 		dp.ssn = htons(ssn);
736 
737 	chunk_len = sizeof(dp) + data_len;
738 	retval = sctp_make_data(asoc, flags, chunk_len, gfp);
739 	if (!retval)
740 		goto nodata;
741 
742 	retval->subh.data_hdr = sctp_addto_chunk(retval, sizeof(dp), &dp);
743 	memcpy(&retval->sinfo, sinfo, sizeof(struct sctp_sndrcvinfo));
744 
745 nodata:
746 	return retval;
747 }
748 
749 /* Create a selective ackowledgement (SACK) for the given
750  * association.  This reports on which TSN's we've seen to date,
751  * including duplicates and gaps.
752  */
753 struct sctp_chunk *sctp_make_sack(const struct sctp_association *asoc)
754 {
755 	struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
756 	struct sctp_association *aptr = (struct sctp_association *)asoc;
757 	struct sctp_gap_ack_block gabs[SCTP_MAX_GABS];
758 	__u16 num_gabs, num_dup_tsns;
759 	struct sctp_transport *trans;
760 	struct sctp_chunk *retval;
761 	struct sctp_sackhdr sack;
762 	__u32 ctsn;
763 	int len;
764 
765 	memset(gabs, 0, sizeof(gabs));
766 	ctsn = sctp_tsnmap_get_ctsn(map);
767 
768 	pr_debug("%s: sackCTSNAck sent:0x%x\n", __func__, ctsn);
769 
770 	/* How much room is needed in the chunk? */
771 	num_gabs = sctp_tsnmap_num_gabs(map, gabs);
772 	num_dup_tsns = sctp_tsnmap_num_dups(map);
773 
774 	/* Initialize the SACK header.  */
775 	sack.cum_tsn_ack	    = htonl(ctsn);
776 	sack.a_rwnd 		    = htonl(asoc->a_rwnd);
777 	sack.num_gap_ack_blocks     = htons(num_gabs);
778 	sack.num_dup_tsns           = htons(num_dup_tsns);
779 
780 	len = sizeof(sack)
781 		+ sizeof(struct sctp_gap_ack_block) * num_gabs
782 		+ sizeof(__u32) * num_dup_tsns;
783 
784 	/* Create the chunk.  */
785 	retval = sctp_make_control(asoc, SCTP_CID_SACK, 0, len, GFP_ATOMIC);
786 	if (!retval)
787 		goto nodata;
788 
789 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
790 	 *
791 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
792 	 * HEARTBEAT ACK, etc.) to the same destination transport
793 	 * address from which it received the DATA or control chunk to
794 	 * which it is replying.  This rule should also be followed if
795 	 * the endpoint is bundling DATA chunks together with the
796 	 * reply chunk.
797 	 *
798 	 * However, when acknowledging multiple DATA chunks received
799 	 * in packets from different source addresses in a single
800 	 * SACK, the SACK chunk may be transmitted to one of the
801 	 * destination transport addresses from which the DATA or
802 	 * control chunks being acknowledged were received.
803 	 *
804 	 * [BUG:  We do not implement the following paragraph.
805 	 * Perhaps we should remember the last transport we used for a
806 	 * SACK and avoid that (if possible) if we have seen any
807 	 * duplicates. --piggy]
808 	 *
809 	 * When a receiver of a duplicate DATA chunk sends a SACK to a
810 	 * multi- homed endpoint it MAY be beneficial to vary the
811 	 * destination address and not use the source address of the
812 	 * DATA chunk.  The reason being that receiving a duplicate
813 	 * from a multi-homed endpoint might indicate that the return
814 	 * path (as specified in the source address of the DATA chunk)
815 	 * for the SACK is broken.
816 	 *
817 	 * [Send to the address from which we last received a DATA chunk.]
818 	 */
819 	retval->transport = asoc->peer.last_data_from;
820 
821 	retval->subh.sack_hdr =
822 		sctp_addto_chunk(retval, sizeof(sack), &sack);
823 
824 	/* Add the gap ack block information.   */
825 	if (num_gabs)
826 		sctp_addto_chunk(retval, sizeof(__u32) * num_gabs,
827 				 gabs);
828 
829 	/* Add the duplicate TSN information.  */
830 	if (num_dup_tsns) {
831 		aptr->stats.idupchunks += num_dup_tsns;
832 		sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns,
833 				 sctp_tsnmap_get_dups(map));
834 	}
835 	/* Once we have a sack generated, check to see what our sack
836 	 * generation is, if its 0, reset the transports to 0, and reset
837 	 * the association generation to 1
838 	 *
839 	 * The idea is that zero is never used as a valid generation for the
840 	 * association so no transport will match after a wrap event like this,
841 	 * Until the next sack
842 	 */
843 	if (++aptr->peer.sack_generation == 0) {
844 		list_for_each_entry(trans, &asoc->peer.transport_addr_list,
845 				    transports)
846 			trans->sack_generation = 0;
847 		aptr->peer.sack_generation = 1;
848 	}
849 nodata:
850 	return retval;
851 }
852 
853 /* Make a SHUTDOWN chunk. */
854 struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
855 				      const struct sctp_chunk *chunk)
856 {
857 	struct sctp_shutdownhdr shut;
858 	struct sctp_chunk *retval;
859 	__u32 ctsn;
860 
861 	ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
862 	shut.cum_tsn_ack = htonl(ctsn);
863 
864 	retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN, 0,
865 				   sizeof(shut), GFP_ATOMIC);
866 	if (!retval)
867 		goto nodata;
868 
869 	retval->subh.shutdown_hdr =
870 		sctp_addto_chunk(retval, sizeof(shut), &shut);
871 
872 	if (chunk)
873 		retval->transport = chunk->transport;
874 nodata:
875 	return retval;
876 }
877 
878 struct sctp_chunk *sctp_make_shutdown_ack(const struct sctp_association *asoc,
879 					  const struct sctp_chunk *chunk)
880 {
881 	struct sctp_chunk *retval;
882 
883 	retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_ACK, 0, 0,
884 				   GFP_ATOMIC);
885 
886 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
887 	 *
888 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
889 	 * HEARTBEAT ACK, * etc.) to the same destination transport
890 	 * address from which it * received the DATA or control chunk
891 	 * to which it is replying.
892 	 *
893 	 * [ACK back to where the SHUTDOWN came from.]
894 	 */
895 	if (retval && chunk)
896 		retval->transport = chunk->transport;
897 
898 	return retval;
899 }
900 
901 struct sctp_chunk *sctp_make_shutdown_complete(
902 					const struct sctp_association *asoc,
903 					const struct sctp_chunk *chunk)
904 {
905 	struct sctp_chunk *retval;
906 	__u8 flags = 0;
907 
908 	/* Set the T-bit if we have no association (vtag will be
909 	 * reflected)
910 	 */
911 	flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;
912 
913 	retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags,
914 				   0, GFP_ATOMIC);
915 
916 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
917 	 *
918 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
919 	 * HEARTBEAT ACK, * etc.) to the same destination transport
920 	 * address from which it * received the DATA or control chunk
921 	 * to which it is replying.
922 	 *
923 	 * [Report SHUTDOWN COMPLETE back to where the SHUTDOWN ACK
924 	 * came from.]
925 	 */
926 	if (retval && chunk)
927 		retval->transport = chunk->transport;
928 
929 	return retval;
930 }
931 
932 /* Create an ABORT.  Note that we set the T bit if we have no
933  * association, except when responding to an INIT (sctpimpguide 2.41).
934  */
935 struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc,
936 				   const struct sctp_chunk *chunk,
937 				   const size_t hint)
938 {
939 	struct sctp_chunk *retval;
940 	__u8 flags = 0;
941 
942 	/* Set the T-bit if we have no association and 'chunk' is not
943 	 * an INIT (vtag will be reflected).
944 	 */
945 	if (!asoc) {
946 		if (chunk && chunk->chunk_hdr &&
947 		    chunk->chunk_hdr->type == SCTP_CID_INIT)
948 			flags = 0;
949 		else
950 			flags = SCTP_CHUNK_FLAG_T;
951 	}
952 
953 	retval = sctp_make_control(asoc, SCTP_CID_ABORT, flags, hint,
954 				   GFP_ATOMIC);
955 
956 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
957 	 *
958 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
959 	 * HEARTBEAT ACK, * etc.) to the same destination transport
960 	 * address from which it * received the DATA or control chunk
961 	 * to which it is replying.
962 	 *
963 	 * [ABORT back to where the offender came from.]
964 	 */
965 	if (retval && chunk)
966 		retval->transport = chunk->transport;
967 
968 	return retval;
969 }
970 
971 /* Helper to create ABORT with a NO_USER_DATA error.  */
972 struct sctp_chunk *sctp_make_abort_no_data(
973 					const struct sctp_association *asoc,
974 					const struct sctp_chunk *chunk,
975 					__u32 tsn)
976 {
977 	struct sctp_chunk *retval;
978 	__be32 payload;
979 
980 	retval = sctp_make_abort(asoc, chunk,
981 				 sizeof(struct sctp_errhdr) + sizeof(tsn));
982 
983 	if (!retval)
984 		goto no_mem;
985 
986 	/* Put the tsn back into network byte order.  */
987 	payload = htonl(tsn);
988 	sctp_init_cause(retval, SCTP_ERROR_NO_DATA, sizeof(payload));
989 	sctp_addto_chunk(retval, sizeof(payload), (const void *)&payload);
990 
991 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
992 	 *
993 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
994 	 * HEARTBEAT ACK, * etc.) to the same destination transport
995 	 * address from which it * received the DATA or control chunk
996 	 * to which it is replying.
997 	 *
998 	 * [ABORT back to where the offender came from.]
999 	 */
1000 	if (chunk)
1001 		retval->transport = chunk->transport;
1002 
1003 no_mem:
1004 	return retval;
1005 }
1006 
1007 /* Helper to create ABORT with a SCTP_ERROR_USER_ABORT error.  */
1008 struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *asoc,
1009 					struct msghdr *msg,
1010 					size_t paylen)
1011 {
1012 	struct sctp_chunk *retval;
1013 	void *payload = NULL;
1014 	int err;
1015 
1016 	retval = sctp_make_abort(asoc, NULL,
1017 				 sizeof(struct sctp_errhdr) + paylen);
1018 	if (!retval)
1019 		goto err_chunk;
1020 
1021 	if (paylen) {
1022 		/* Put the msg_iov together into payload.  */
1023 		payload = kmalloc(paylen, GFP_KERNEL);
1024 		if (!payload)
1025 			goto err_payload;
1026 
1027 		err = memcpy_from_msg(payload, msg, paylen);
1028 		if (err < 0)
1029 			goto err_copy;
1030 	}
1031 
1032 	sctp_init_cause(retval, SCTP_ERROR_USER_ABORT, paylen);
1033 	sctp_addto_chunk(retval, paylen, payload);
1034 
1035 	if (paylen)
1036 		kfree(payload);
1037 
1038 	return retval;
1039 
1040 err_copy:
1041 	kfree(payload);
1042 err_payload:
1043 	sctp_chunk_free(retval);
1044 	retval = NULL;
1045 err_chunk:
1046 	return retval;
1047 }
1048 
1049 /* Append bytes to the end of a parameter.  Will panic if chunk is not big
1050  * enough.
1051  */
1052 static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
1053 			      const void *data)
1054 {
1055 	int chunklen = ntohs(chunk->chunk_hdr->length);
1056 	void *target;
1057 
1058 	target = skb_put(chunk->skb, len);
1059 
1060 	if (data)
1061 		memcpy(target, data, len);
1062 	else
1063 		memset(target, 0, len);
1064 
1065 	/* Adjust the chunk length field.  */
1066 	chunk->chunk_hdr->length = htons(chunklen + len);
1067 	chunk->chunk_end = skb_tail_pointer(chunk->skb);
1068 
1069 	return target;
1070 }
1071 
1072 /* Make an ABORT chunk with a PROTOCOL VIOLATION cause code. */
1073 struct sctp_chunk *sctp_make_abort_violation(
1074 					const struct sctp_association *asoc,
1075 					const struct sctp_chunk *chunk,
1076 					const __u8 *payload,
1077 					const size_t paylen)
1078 {
1079 	struct sctp_chunk  *retval;
1080 	struct sctp_paramhdr phdr;
1081 
1082 	retval = sctp_make_abort(asoc, chunk, sizeof(struct sctp_errhdr) +
1083 					      paylen + sizeof(phdr));
1084 	if (!retval)
1085 		goto end;
1086 
1087 	sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, paylen +
1088 							    sizeof(phdr));
1089 
1090 	phdr.type = htons(chunk->chunk_hdr->type);
1091 	phdr.length = chunk->chunk_hdr->length;
1092 	sctp_addto_chunk(retval, paylen, payload);
1093 	sctp_addto_param(retval, sizeof(phdr), &phdr);
1094 
1095 end:
1096 	return retval;
1097 }
1098 
1099 struct sctp_chunk *sctp_make_violation_paramlen(
1100 					const struct sctp_association *asoc,
1101 					const struct sctp_chunk *chunk,
1102 					struct sctp_paramhdr *param)
1103 {
1104 	static const char error[] = "The following parameter had invalid length:";
1105 	size_t payload_len = sizeof(error) + sizeof(struct sctp_errhdr) +
1106 			     sizeof(*param);
1107 	struct sctp_chunk *retval;
1108 
1109 	retval = sctp_make_abort(asoc, chunk, payload_len);
1110 	if (!retval)
1111 		goto nodata;
1112 
1113 	sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION,
1114 			sizeof(error) + sizeof(*param));
1115 	sctp_addto_chunk(retval, sizeof(error), error);
1116 	sctp_addto_param(retval, sizeof(*param), param);
1117 
1118 nodata:
1119 	return retval;
1120 }
1121 
1122 struct sctp_chunk *sctp_make_violation_max_retrans(
1123 					const struct sctp_association *asoc,
1124 					const struct sctp_chunk *chunk)
1125 {
1126 	static const char error[] = "Association exceeded its max_retans count";
1127 	size_t payload_len = sizeof(error) + sizeof(struct sctp_errhdr);
1128 	struct sctp_chunk *retval;
1129 
1130 	retval = sctp_make_abort(asoc, chunk, payload_len);
1131 	if (!retval)
1132 		goto nodata;
1133 
1134 	sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, sizeof(error));
1135 	sctp_addto_chunk(retval, sizeof(error), error);
1136 
1137 nodata:
1138 	return retval;
1139 }
1140 
1141 /* Make a HEARTBEAT chunk.  */
1142 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
1143 				       const struct sctp_transport *transport)
1144 {
1145 	struct sctp_sender_hb_info hbinfo;
1146 	struct sctp_chunk *retval;
1147 
1148 	retval = sctp_make_control(asoc, SCTP_CID_HEARTBEAT, 0,
1149 				   sizeof(hbinfo), GFP_ATOMIC);
1150 
1151 	if (!retval)
1152 		goto nodata;
1153 
1154 	hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO;
1155 	hbinfo.param_hdr.length = htons(sizeof(hbinfo));
1156 	hbinfo.daddr = transport->ipaddr;
1157 	hbinfo.sent_at = jiffies;
1158 	hbinfo.hb_nonce = transport->hb_nonce;
1159 
1160 	/* Cast away the 'const', as this is just telling the chunk
1161 	 * what transport it belongs to.
1162 	 */
1163 	retval->transport = (struct sctp_transport *) transport;
1164 	retval->subh.hbs_hdr = sctp_addto_chunk(retval, sizeof(hbinfo),
1165 						&hbinfo);
1166 
1167 nodata:
1168 	return retval;
1169 }
1170 
1171 struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc,
1172 					   const struct sctp_chunk *chunk,
1173 					   const void *payload,
1174 					   const size_t paylen)
1175 {
1176 	struct sctp_chunk *retval;
1177 
1178 	retval  = sctp_make_control(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen,
1179 				    GFP_ATOMIC);
1180 	if (!retval)
1181 		goto nodata;
1182 
1183 	retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);
1184 
1185 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
1186 	 *
1187 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1188 	 * HEARTBEAT ACK, * etc.) to the same destination transport
1189 	 * address from which it * received the DATA or control chunk
1190 	 * to which it is replying.
1191 	 *
1192 	 * [HBACK back to where the HEARTBEAT came from.]
1193 	 */
1194 	if (chunk)
1195 		retval->transport = chunk->transport;
1196 
1197 nodata:
1198 	return retval;
1199 }
1200 
1201 /* Create an Operation Error chunk with the specified space reserved.
1202  * This routine can be used for containing multiple causes in the chunk.
1203  */
1204 static struct sctp_chunk *sctp_make_op_error_space(
1205 					const struct sctp_association *asoc,
1206 					const struct sctp_chunk *chunk,
1207 					size_t size)
1208 {
1209 	struct sctp_chunk *retval;
1210 
1211 	retval = sctp_make_control(asoc, SCTP_CID_ERROR, 0,
1212 				   sizeof(struct sctp_errhdr) + size,
1213 				   GFP_ATOMIC);
1214 	if (!retval)
1215 		goto nodata;
1216 
1217 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
1218 	 *
1219 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1220 	 * HEARTBEAT ACK, etc.) to the same destination transport
1221 	 * address from which it received the DATA or control chunk
1222 	 * to which it is replying.
1223 	 *
1224 	 */
1225 	if (chunk)
1226 		retval->transport = chunk->transport;
1227 
1228 nodata:
1229 	return retval;
1230 }
1231 
1232 /* Create an Operation Error chunk of a fixed size,
1233  * specifically, max(asoc->pathmtu, SCTP_DEFAULT_MAXSEGMENT)
1234  * This is a helper function to allocate an error chunk for
1235  * for those invalid parameter codes in which we may not want
1236  * to report all the errors, if the incoming chunk is large
1237  */
1238 static inline struct sctp_chunk *sctp_make_op_error_fixed(
1239 					const struct sctp_association *asoc,
1240 					const struct sctp_chunk *chunk)
1241 {
1242 	size_t size = asoc ? asoc->pathmtu : 0;
1243 
1244 	if (!size)
1245 		size = SCTP_DEFAULT_MAXSEGMENT;
1246 
1247 	return sctp_make_op_error_space(asoc, chunk, size);
1248 }
1249 
1250 /* Create an Operation Error chunk.  */
1251 struct sctp_chunk *sctp_make_op_error(const struct sctp_association *asoc,
1252 				      const struct sctp_chunk *chunk,
1253 				      __be16 cause_code, const void *payload,
1254 				      size_t paylen, size_t reserve_tail)
1255 {
1256 	struct sctp_chunk *retval;
1257 
1258 	retval = sctp_make_op_error_space(asoc, chunk, paylen + reserve_tail);
1259 	if (!retval)
1260 		goto nodata;
1261 
1262 	sctp_init_cause(retval, cause_code, paylen + reserve_tail);
1263 	sctp_addto_chunk(retval, paylen, payload);
1264 	if (reserve_tail)
1265 		sctp_addto_param(retval, reserve_tail, NULL);
1266 
1267 nodata:
1268 	return retval;
1269 }
1270 
1271 struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc)
1272 {
1273 	struct sctp_authhdr auth_hdr;
1274 	struct sctp_hmac *hmac_desc;
1275 	struct sctp_chunk *retval;
1276 	__u8 *hmac;
1277 
1278 	/* Get the first hmac that the peer told us to use */
1279 	hmac_desc = sctp_auth_asoc_get_hmac(asoc);
1280 	if (unlikely(!hmac_desc))
1281 		return NULL;
1282 
1283 	retval = sctp_make_control(asoc, SCTP_CID_AUTH, 0,
1284 				   hmac_desc->hmac_len + sizeof(auth_hdr),
1285 				   GFP_ATOMIC);
1286 	if (!retval)
1287 		return NULL;
1288 
1289 	auth_hdr.hmac_id = htons(hmac_desc->hmac_id);
1290 	auth_hdr.shkey_id = htons(asoc->active_key_id);
1291 
1292 	retval->subh.auth_hdr = sctp_addto_chunk(retval, sizeof(auth_hdr),
1293 						 &auth_hdr);
1294 
1295 	hmac = skb_put_zero(retval->skb, hmac_desc->hmac_len);
1296 
1297 	/* Adjust the chunk header to include the empty MAC */
1298 	retval->chunk_hdr->length =
1299 		htons(ntohs(retval->chunk_hdr->length) + hmac_desc->hmac_len);
1300 	retval->chunk_end = skb_tail_pointer(retval->skb);
1301 
1302 	return retval;
1303 }
1304 
1305 
1306 /********************************************************************
1307  * 2nd Level Abstractions
1308  ********************************************************************/
1309 
1310 /* Turn an skb into a chunk.
1311  * FIXME: Eventually move the structure directly inside the skb->cb[].
1312  *
1313  * sctpimpguide-05.txt Section 2.8.2
1314  * M1) Each time a new DATA chunk is transmitted
1315  * set the 'TSN.Missing.Report' count for that TSN to 0. The
1316  * 'TSN.Missing.Report' count will be used to determine missing chunks
1317  * and when to fast retransmit.
1318  *
1319  */
1320 struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
1321 				 const struct sctp_association *asoc,
1322 				 struct sock *sk, gfp_t gfp)
1323 {
1324 	struct sctp_chunk *retval;
1325 
1326 	retval = kmem_cache_zalloc(sctp_chunk_cachep, gfp);
1327 
1328 	if (!retval)
1329 		goto nodata;
1330 	if (!sk)
1331 		pr_debug("%s: chunkifying skb:%p w/o an sk\n", __func__, skb);
1332 
1333 	INIT_LIST_HEAD(&retval->list);
1334 	retval->skb		= skb;
1335 	retval->asoc		= (struct sctp_association *)asoc;
1336 	retval->singleton	= 1;
1337 
1338 	retval->fast_retransmit = SCTP_CAN_FRTX;
1339 
1340 	/* Polish the bead hole.  */
1341 	INIT_LIST_HEAD(&retval->transmitted_list);
1342 	INIT_LIST_HEAD(&retval->frag_list);
1343 	SCTP_DBG_OBJCNT_INC(chunk);
1344 	refcount_set(&retval->refcnt, 1);
1345 
1346 nodata:
1347 	return retval;
1348 }
1349 
1350 /* Set chunk->source and dest based on the IP header in chunk->skb.  */
1351 void sctp_init_addrs(struct sctp_chunk *chunk, union sctp_addr *src,
1352 		     union sctp_addr *dest)
1353 {
1354 	memcpy(&chunk->source, src, sizeof(union sctp_addr));
1355 	memcpy(&chunk->dest, dest, sizeof(union sctp_addr));
1356 }
1357 
1358 /* Extract the source address from a chunk.  */
1359 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk)
1360 {
1361 	/* If we have a known transport, use that.  */
1362 	if (chunk->transport) {
1363 		return &chunk->transport->ipaddr;
1364 	} else {
1365 		/* Otherwise, extract it from the IP header.  */
1366 		return &chunk->source;
1367 	}
1368 }
1369 
1370 /* Create a new chunk, setting the type and flags headers from the
1371  * arguments, reserving enough space for a 'paylen' byte payload.
1372  */
1373 static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc,
1374 					   __u8 type, __u8 flags, int paylen,
1375 					   gfp_t gfp)
1376 {
1377 	struct sctp_chunkhdr *chunk_hdr;
1378 	struct sctp_chunk *retval;
1379 	struct sk_buff *skb;
1380 	struct sock *sk;
1381 
1382 	/* No need to allocate LL here, as this is only a chunk. */
1383 	skb = alloc_skb(SCTP_PAD4(sizeof(*chunk_hdr) + paylen), gfp);
1384 	if (!skb)
1385 		goto nodata;
1386 
1387 	/* Make room for the chunk header.  */
1388 	chunk_hdr = (struct sctp_chunkhdr *)skb_put(skb, sizeof(*chunk_hdr));
1389 	chunk_hdr->type	  = type;
1390 	chunk_hdr->flags  = flags;
1391 	chunk_hdr->length = htons(sizeof(*chunk_hdr));
1392 
1393 	sk = asoc ? asoc->base.sk : NULL;
1394 	retval = sctp_chunkify(skb, asoc, sk, gfp);
1395 	if (!retval) {
1396 		kfree_skb(skb);
1397 		goto nodata;
1398 	}
1399 
1400 	retval->chunk_hdr = chunk_hdr;
1401 	retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(*chunk_hdr);
1402 
1403 	/* Determine if the chunk needs to be authenticated */
1404 	if (sctp_auth_send_cid(type, asoc))
1405 		retval->auth = 1;
1406 
1407 	return retval;
1408 nodata:
1409 	return NULL;
1410 }
1411 
1412 static struct sctp_chunk *sctp_make_data(const struct sctp_association *asoc,
1413 					 __u8 flags, int paylen, gfp_t gfp)
1414 {
1415 	return _sctp_make_chunk(asoc, SCTP_CID_DATA, flags, paylen, gfp);
1416 }
1417 
1418 static struct sctp_chunk *sctp_make_control(const struct sctp_association *asoc,
1419 					    __u8 type, __u8 flags, int paylen,
1420 					    gfp_t gfp)
1421 {
1422 	struct sctp_chunk *chunk;
1423 
1424 	chunk = _sctp_make_chunk(asoc, type, flags, paylen, gfp);
1425 	if (chunk)
1426 		sctp_control_set_owner_w(chunk);
1427 
1428 	return chunk;
1429 }
1430 
1431 /* Release the memory occupied by a chunk.  */
1432 static void sctp_chunk_destroy(struct sctp_chunk *chunk)
1433 {
1434 	BUG_ON(!list_empty(&chunk->list));
1435 	list_del_init(&chunk->transmitted_list);
1436 
1437 	consume_skb(chunk->skb);
1438 	consume_skb(chunk->auth_chunk);
1439 
1440 	SCTP_DBG_OBJCNT_DEC(chunk);
1441 	kmem_cache_free(sctp_chunk_cachep, chunk);
1442 }
1443 
1444 /* Possibly, free the chunk.  */
1445 void sctp_chunk_free(struct sctp_chunk *chunk)
1446 {
1447 	/* Release our reference on the message tracker. */
1448 	if (chunk->msg)
1449 		sctp_datamsg_put(chunk->msg);
1450 
1451 	sctp_chunk_put(chunk);
1452 }
1453 
1454 /* Grab a reference to the chunk. */
1455 void sctp_chunk_hold(struct sctp_chunk *ch)
1456 {
1457 	refcount_inc(&ch->refcnt);
1458 }
1459 
1460 /* Release a reference to the chunk. */
1461 void sctp_chunk_put(struct sctp_chunk *ch)
1462 {
1463 	if (refcount_dec_and_test(&ch->refcnt))
1464 		sctp_chunk_destroy(ch);
1465 }
1466 
1467 /* Append bytes to the end of a chunk.  Will panic if chunk is not big
1468  * enough.
1469  */
1470 void *sctp_addto_chunk(struct sctp_chunk *chunk, int len, const void *data)
1471 {
1472 	int chunklen = ntohs(chunk->chunk_hdr->length);
1473 	int padlen = SCTP_PAD4(chunklen) - chunklen;
1474 	void *target;
1475 
1476 	skb_put_zero(chunk->skb, padlen);
1477 	target = skb_put_data(chunk->skb, data, len);
1478 
1479 	/* Adjust the chunk length field.  */
1480 	chunk->chunk_hdr->length = htons(chunklen + padlen + len);
1481 	chunk->chunk_end = skb_tail_pointer(chunk->skb);
1482 
1483 	return target;
1484 }
1485 
1486 /* Append bytes to the end of a chunk. Returns NULL if there isn't sufficient
1487  * space in the chunk
1488  */
1489 static void *sctp_addto_chunk_fixed(struct sctp_chunk *chunk,
1490 				    int len, const void *data)
1491 {
1492 	if (skb_tailroom(chunk->skb) >= len)
1493 		return sctp_addto_chunk(chunk, len, data);
1494 	else
1495 		return NULL;
1496 }
1497 
1498 /* Append bytes from user space to the end of a chunk.  Will panic if
1499  * chunk is not big enough.
1500  * Returns a kernel err value.
1501  */
1502 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
1503 			  struct iov_iter *from)
1504 {
1505 	void *target;
1506 
1507 	/* Make room in chunk for data.  */
1508 	target = skb_put(chunk->skb, len);
1509 
1510 	/* Copy data (whole iovec) into chunk */
1511 	if (!copy_from_iter_full(target, len, from))
1512 		return -EFAULT;
1513 
1514 	/* Adjust the chunk length field.  */
1515 	chunk->chunk_hdr->length =
1516 		htons(ntohs(chunk->chunk_hdr->length) + len);
1517 	chunk->chunk_end = skb_tail_pointer(chunk->skb);
1518 
1519 	return 0;
1520 }
1521 
1522 /* Helper function to assign a TSN if needed.  This assumes that both
1523  * the data_hdr and association have already been assigned.
1524  */
1525 void sctp_chunk_assign_ssn(struct sctp_chunk *chunk)
1526 {
1527 	struct sctp_stream *stream;
1528 	struct sctp_chunk *lchunk;
1529 	struct sctp_datamsg *msg;
1530 	__u16 ssn, sid;
1531 
1532 	if (chunk->has_ssn)
1533 		return;
1534 
1535 	/* All fragments will be on the same stream */
1536 	sid = ntohs(chunk->subh.data_hdr->stream);
1537 	stream = &chunk->asoc->stream;
1538 
1539 	/* Now assign the sequence number to the entire message.
1540 	 * All fragments must have the same stream sequence number.
1541 	 */
1542 	msg = chunk->msg;
1543 	list_for_each_entry(lchunk, &msg->chunks, frag_list) {
1544 		if (lchunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
1545 			ssn = 0;
1546 		} else {
1547 			if (lchunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG)
1548 				ssn = sctp_ssn_next(stream, out, sid);
1549 			else
1550 				ssn = sctp_ssn_peek(stream, out, sid);
1551 		}
1552 
1553 		lchunk->subh.data_hdr->ssn = htons(ssn);
1554 		lchunk->has_ssn = 1;
1555 	}
1556 }
1557 
1558 /* Helper function to assign a TSN if needed.  This assumes that both
1559  * the data_hdr and association have already been assigned.
1560  */
1561 void sctp_chunk_assign_tsn(struct sctp_chunk *chunk)
1562 {
1563 	if (!chunk->has_tsn) {
1564 		/* This is the last possible instant to
1565 		 * assign a TSN.
1566 		 */
1567 		chunk->subh.data_hdr->tsn =
1568 			htonl(sctp_association_get_next_tsn(chunk->asoc));
1569 		chunk->has_tsn = 1;
1570 	}
1571 }
1572 
1573 /* Create a CLOSED association to use with an incoming packet.  */
1574 struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *ep,
1575 					     struct sctp_chunk *chunk,
1576 					     gfp_t gfp)
1577 {
1578 	struct sctp_association *asoc;
1579 	enum sctp_scope scope;
1580 	struct sk_buff *skb;
1581 
1582 	/* Create the bare association.  */
1583 	scope = sctp_scope(sctp_source(chunk));
1584 	asoc = sctp_association_new(ep, ep->base.sk, scope, gfp);
1585 	if (!asoc)
1586 		goto nodata;
1587 	asoc->temp = 1;
1588 	skb = chunk->skb;
1589 	/* Create an entry for the source address of the packet.  */
1590 	SCTP_INPUT_CB(skb)->af->from_skb(&asoc->c.peer_addr, skb, 1);
1591 
1592 nodata:
1593 	return asoc;
1594 }
1595 
1596 /* Build a cookie representing asoc.
1597  * This INCLUDES the param header needed to put the cookie in the INIT ACK.
1598  */
1599 static struct sctp_cookie_param *sctp_pack_cookie(
1600 					const struct sctp_endpoint *ep,
1601 					const struct sctp_association *asoc,
1602 					const struct sctp_chunk *init_chunk,
1603 					int *cookie_len, const __u8 *raw_addrs,
1604 					int addrs_len)
1605 {
1606 	struct sctp_signed_cookie *cookie;
1607 	struct sctp_cookie_param *retval;
1608 	int headersize, bodysize;
1609 
1610 	/* Header size is static data prior to the actual cookie, including
1611 	 * any padding.
1612 	 */
1613 	headersize = sizeof(struct sctp_paramhdr) +
1614 		     (sizeof(struct sctp_signed_cookie) -
1615 		      sizeof(struct sctp_cookie));
1616 	bodysize = sizeof(struct sctp_cookie)
1617 		+ ntohs(init_chunk->chunk_hdr->length) + addrs_len;
1618 
1619 	/* Pad out the cookie to a multiple to make the signature
1620 	 * functions simpler to write.
1621 	 */
1622 	if (bodysize % SCTP_COOKIE_MULTIPLE)
1623 		bodysize += SCTP_COOKIE_MULTIPLE
1624 			- (bodysize % SCTP_COOKIE_MULTIPLE);
1625 	*cookie_len = headersize + bodysize;
1626 
1627 	/* Clear this memory since we are sending this data structure
1628 	 * out on the network.
1629 	 */
1630 	retval = kzalloc(*cookie_len, GFP_ATOMIC);
1631 	if (!retval)
1632 		goto nodata;
1633 
1634 	cookie = (struct sctp_signed_cookie *) retval->body;
1635 
1636 	/* Set up the parameter header.  */
1637 	retval->p.type = SCTP_PARAM_STATE_COOKIE;
1638 	retval->p.length = htons(*cookie_len);
1639 
1640 	/* Copy the cookie part of the association itself.  */
1641 	cookie->c = asoc->c;
1642 	/* Save the raw address list length in the cookie. */
1643 	cookie->c.raw_addr_list_len = addrs_len;
1644 
1645 	/* Remember PR-SCTP capability. */
1646 	cookie->c.prsctp_capable = asoc->peer.prsctp_capable;
1647 
1648 	/* Save adaptation indication in the cookie. */
1649 	cookie->c.adaptation_ind = asoc->peer.adaptation_ind;
1650 
1651 	/* Set an expiration time for the cookie.  */
1652 	cookie->c.expiration = ktime_add(asoc->cookie_life,
1653 					 ktime_get_real());
1654 
1655 	/* Copy the peer's init packet.  */
1656 	memcpy(&cookie->c.peer_init[0], init_chunk->chunk_hdr,
1657 	       ntohs(init_chunk->chunk_hdr->length));
1658 
1659 	/* Copy the raw local address list of the association. */
1660 	memcpy((__u8 *)&cookie->c.peer_init[0] +
1661 	       ntohs(init_chunk->chunk_hdr->length), raw_addrs, addrs_len);
1662 
1663 	if (sctp_sk(ep->base.sk)->hmac) {
1664 		SHASH_DESC_ON_STACK(desc, sctp_sk(ep->base.sk)->hmac);
1665 		int err;
1666 
1667 		/* Sign the message.  */
1668 		desc->tfm = sctp_sk(ep->base.sk)->hmac;
1669 		desc->flags = 0;
1670 
1671 		err = crypto_shash_setkey(desc->tfm, ep->secret_key,
1672 					  sizeof(ep->secret_key)) ?:
1673 		      crypto_shash_digest(desc, (u8 *)&cookie->c, bodysize,
1674 					  cookie->signature);
1675 		shash_desc_zero(desc);
1676 		if (err)
1677 			goto free_cookie;
1678 	}
1679 
1680 	return retval;
1681 
1682 free_cookie:
1683 	kfree(retval);
1684 nodata:
1685 	*cookie_len = 0;
1686 	return NULL;
1687 }
1688 
1689 /* Unpack the cookie from COOKIE ECHO chunk, recreating the association.  */
1690 struct sctp_association *sctp_unpack_cookie(
1691 					const struct sctp_endpoint *ep,
1692 					const struct sctp_association *asoc,
1693 					struct sctp_chunk *chunk, gfp_t gfp,
1694 					int *error, struct sctp_chunk **errp)
1695 {
1696 	struct sctp_association *retval = NULL;
1697 	int headersize, bodysize, fixed_size;
1698 	struct sctp_signed_cookie *cookie;
1699 	struct sk_buff *skb = chunk->skb;
1700 	struct sctp_cookie *bear_cookie;
1701 	__u8 *digest = ep->digest;
1702 	enum sctp_scope scope;
1703 	unsigned int len;
1704 	ktime_t kt;
1705 
1706 	/* Header size is static data prior to the actual cookie, including
1707 	 * any padding.
1708 	 */
1709 	headersize = sizeof(struct sctp_chunkhdr) +
1710 		     (sizeof(struct sctp_signed_cookie) -
1711 		      sizeof(struct sctp_cookie));
1712 	bodysize = ntohs(chunk->chunk_hdr->length) - headersize;
1713 	fixed_size = headersize + sizeof(struct sctp_cookie);
1714 
1715 	/* Verify that the chunk looks like it even has a cookie.
1716 	 * There must be enough room for our cookie and our peer's
1717 	 * INIT chunk.
1718 	 */
1719 	len = ntohs(chunk->chunk_hdr->length);
1720 	if (len < fixed_size + sizeof(struct sctp_chunkhdr))
1721 		goto malformed;
1722 
1723 	/* Verify that the cookie has been padded out. */
1724 	if (bodysize % SCTP_COOKIE_MULTIPLE)
1725 		goto malformed;
1726 
1727 	/* Process the cookie.  */
1728 	cookie = chunk->subh.cookie_hdr;
1729 	bear_cookie = &cookie->c;
1730 
1731 	if (!sctp_sk(ep->base.sk)->hmac)
1732 		goto no_hmac;
1733 
1734 	/* Check the signature.  */
1735 	{
1736 		SHASH_DESC_ON_STACK(desc, sctp_sk(ep->base.sk)->hmac);
1737 		int err;
1738 
1739 		desc->tfm = sctp_sk(ep->base.sk)->hmac;
1740 		desc->flags = 0;
1741 
1742 		err = crypto_shash_setkey(desc->tfm, ep->secret_key,
1743 					  sizeof(ep->secret_key)) ?:
1744 		      crypto_shash_digest(desc, (u8 *)bear_cookie, bodysize,
1745 					  digest);
1746 		shash_desc_zero(desc);
1747 
1748 		if (err) {
1749 			*error = -SCTP_IERROR_NOMEM;
1750 			goto fail;
1751 		}
1752 	}
1753 
1754 	if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
1755 		*error = -SCTP_IERROR_BAD_SIG;
1756 		goto fail;
1757 	}
1758 
1759 no_hmac:
1760 	/* IG Section 2.35.2:
1761 	 *  3) Compare the port numbers and the verification tag contained
1762 	 *     within the COOKIE ECHO chunk to the actual port numbers and the
1763 	 *     verification tag within the SCTP common header of the received
1764 	 *     packet. If these values do not match the packet MUST be silently
1765 	 *     discarded,
1766 	 */
1767 	if (ntohl(chunk->sctp_hdr->vtag) != bear_cookie->my_vtag) {
1768 		*error = -SCTP_IERROR_BAD_TAG;
1769 		goto fail;
1770 	}
1771 
1772 	if (chunk->sctp_hdr->source != bear_cookie->peer_addr.v4.sin_port ||
1773 	    ntohs(chunk->sctp_hdr->dest) != bear_cookie->my_port) {
1774 		*error = -SCTP_IERROR_BAD_PORTS;
1775 		goto fail;
1776 	}
1777 
1778 	/* Check to see if the cookie is stale.  If there is already
1779 	 * an association, there is no need to check cookie's expiration
1780 	 * for init collision case of lost COOKIE ACK.
1781 	 * If skb has been timestamped, then use the stamp, otherwise
1782 	 * use current time.  This introduces a small possibility that
1783 	 * that a cookie may be considered expired, but his would only slow
1784 	 * down the new association establishment instead of every packet.
1785 	 */
1786 	if (sock_flag(ep->base.sk, SOCK_TIMESTAMP))
1787 		kt = skb_get_ktime(skb);
1788 	else
1789 		kt = ktime_get_real();
1790 
1791 	if (!asoc && ktime_before(bear_cookie->expiration, kt)) {
1792 		/*
1793 		 * Section 3.3.10.3 Stale Cookie Error (3)
1794 		 *
1795 		 * Cause of error
1796 		 * ---------------
1797 		 * Stale Cookie Error:  Indicates the receipt of a valid State
1798 		 * Cookie that has expired.
1799 		 */
1800 		len = ntohs(chunk->chunk_hdr->length);
1801 		*errp = sctp_make_op_error_space(asoc, chunk, len);
1802 		if (*errp) {
1803 			suseconds_t usecs = ktime_to_us(ktime_sub(kt, bear_cookie->expiration));
1804 			__be32 n = htonl(usecs);
1805 
1806 			sctp_init_cause(*errp, SCTP_ERROR_STALE_COOKIE,
1807 					sizeof(n));
1808 			sctp_addto_chunk(*errp, sizeof(n), &n);
1809 			*error = -SCTP_IERROR_STALE_COOKIE;
1810 		} else
1811 			*error = -SCTP_IERROR_NOMEM;
1812 
1813 		goto fail;
1814 	}
1815 
1816 	/* Make a new base association.  */
1817 	scope = sctp_scope(sctp_source(chunk));
1818 	retval = sctp_association_new(ep, ep->base.sk, scope, gfp);
1819 	if (!retval) {
1820 		*error = -SCTP_IERROR_NOMEM;
1821 		goto fail;
1822 	}
1823 
1824 	/* Set up our peer's port number.  */
1825 	retval->peer.port = ntohs(chunk->sctp_hdr->source);
1826 
1827 	/* Populate the association from the cookie.  */
1828 	memcpy(&retval->c, bear_cookie, sizeof(*bear_cookie));
1829 
1830 	if (sctp_assoc_set_bind_addr_from_cookie(retval, bear_cookie,
1831 						 GFP_ATOMIC) < 0) {
1832 		*error = -SCTP_IERROR_NOMEM;
1833 		goto fail;
1834 	}
1835 
1836 	/* Also, add the destination address. */
1837 	if (list_empty(&retval->base.bind_addr.address_list)) {
1838 		sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest,
1839 				   sizeof(chunk->dest), SCTP_ADDR_SRC,
1840 				   GFP_ATOMIC);
1841 	}
1842 
1843 	retval->next_tsn = retval->c.initial_tsn;
1844 	retval->ctsn_ack_point = retval->next_tsn - 1;
1845 	retval->addip_serial = retval->c.initial_tsn;
1846 	retval->strreset_outseq = retval->c.initial_tsn;
1847 	retval->adv_peer_ack_point = retval->ctsn_ack_point;
1848 	retval->peer.prsctp_capable = retval->c.prsctp_capable;
1849 	retval->peer.adaptation_ind = retval->c.adaptation_ind;
1850 
1851 	/* The INIT stuff will be done by the side effects.  */
1852 	return retval;
1853 
1854 fail:
1855 	if (retval)
1856 		sctp_association_free(retval);
1857 
1858 	return NULL;
1859 
1860 malformed:
1861 	/* Yikes!  The packet is either corrupt or deliberately
1862 	 * malformed.
1863 	 */
1864 	*error = -SCTP_IERROR_MALFORMED;
1865 	goto fail;
1866 }
1867 
1868 /********************************************************************
1869  * 3rd Level Abstractions
1870  ********************************************************************/
1871 
1872 struct __sctp_missing {
1873 	__be32 num_missing;
1874 	__be16 type;
1875 }  __packed;
1876 
1877 /*
1878  * Report a missing mandatory parameter.
1879  */
1880 static int sctp_process_missing_param(const struct sctp_association *asoc,
1881 				      enum sctp_param paramtype,
1882 				      struct sctp_chunk *chunk,
1883 				      struct sctp_chunk **errp)
1884 {
1885 	struct __sctp_missing report;
1886 	__u16 len;
1887 
1888 	len = SCTP_PAD4(sizeof(report));
1889 
1890 	/* Make an ERROR chunk, preparing enough room for
1891 	 * returning multiple unknown parameters.
1892 	 */
1893 	if (!*errp)
1894 		*errp = sctp_make_op_error_space(asoc, chunk, len);
1895 
1896 	if (*errp) {
1897 		report.num_missing = htonl(1);
1898 		report.type = paramtype;
1899 		sctp_init_cause(*errp, SCTP_ERROR_MISS_PARAM,
1900 				sizeof(report));
1901 		sctp_addto_chunk(*errp, sizeof(report), &report);
1902 	}
1903 
1904 	/* Stop processing this chunk. */
1905 	return 0;
1906 }
1907 
1908 /* Report an Invalid Mandatory Parameter.  */
1909 static int sctp_process_inv_mandatory(const struct sctp_association *asoc,
1910 				      struct sctp_chunk *chunk,
1911 				      struct sctp_chunk **errp)
1912 {
1913 	/* Invalid Mandatory Parameter Error has no payload. */
1914 
1915 	if (!*errp)
1916 		*errp = sctp_make_op_error_space(asoc, chunk, 0);
1917 
1918 	if (*errp)
1919 		sctp_init_cause(*errp, SCTP_ERROR_INV_PARAM, 0);
1920 
1921 	/* Stop processing this chunk. */
1922 	return 0;
1923 }
1924 
1925 static int sctp_process_inv_paramlength(const struct sctp_association *asoc,
1926 					struct sctp_paramhdr *param,
1927 					const struct sctp_chunk *chunk,
1928 					struct sctp_chunk **errp)
1929 {
1930 	/* This is a fatal error.  Any accumulated non-fatal errors are
1931 	 * not reported.
1932 	 */
1933 	if (*errp)
1934 		sctp_chunk_free(*errp);
1935 
1936 	/* Create an error chunk and fill it in with our payload. */
1937 	*errp = sctp_make_violation_paramlen(asoc, chunk, param);
1938 
1939 	return 0;
1940 }
1941 
1942 
1943 /* Do not attempt to handle the HOST_NAME parm.  However, do
1944  * send back an indicator to the peer.
1945  */
1946 static int sctp_process_hn_param(const struct sctp_association *asoc,
1947 				 union sctp_params param,
1948 				 struct sctp_chunk *chunk,
1949 				 struct sctp_chunk **errp)
1950 {
1951 	__u16 len = ntohs(param.p->length);
1952 
1953 	/* Processing of the HOST_NAME parameter will generate an
1954 	 * ABORT.  If we've accumulated any non-fatal errors, they
1955 	 * would be unrecognized parameters and we should not include
1956 	 * them in the ABORT.
1957 	 */
1958 	if (*errp)
1959 		sctp_chunk_free(*errp);
1960 
1961 	*errp = sctp_make_op_error_space(asoc, chunk, len);
1962 
1963 	if (*errp) {
1964 		sctp_init_cause(*errp, SCTP_ERROR_DNS_FAILED, len);
1965 		sctp_addto_chunk(*errp, len, param.v);
1966 	}
1967 
1968 	/* Stop processing this chunk. */
1969 	return 0;
1970 }
1971 
1972 static int sctp_verify_ext_param(struct net *net, union sctp_params param)
1973 {
1974 	__u16 num_ext = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
1975 	int have_asconf = 0;
1976 	int have_auth = 0;
1977 	int i;
1978 
1979 	for (i = 0; i < num_ext; i++) {
1980 		switch (param.ext->chunks[i]) {
1981 		case SCTP_CID_AUTH:
1982 			have_auth = 1;
1983 			break;
1984 		case SCTP_CID_ASCONF:
1985 		case SCTP_CID_ASCONF_ACK:
1986 			have_asconf = 1;
1987 			break;
1988 		}
1989 	}
1990 
1991 	/* ADD-IP Security: The draft requires us to ABORT or ignore the
1992 	 * INIT/INIT-ACK if ADD-IP is listed, but AUTH is not.  Do this
1993 	 * only if ADD-IP is turned on and we are not backward-compatible
1994 	 * mode.
1995 	 */
1996 	if (net->sctp.addip_noauth)
1997 		return 1;
1998 
1999 	if (net->sctp.addip_enable && !have_auth && have_asconf)
2000 		return 0;
2001 
2002 	return 1;
2003 }
2004 
2005 static void sctp_process_ext_param(struct sctp_association *asoc,
2006 				   union sctp_params param)
2007 {
2008 	__u16 num_ext = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
2009 	struct net *net = sock_net(asoc->base.sk);
2010 	int i;
2011 
2012 	for (i = 0; i < num_ext; i++) {
2013 		switch (param.ext->chunks[i]) {
2014 		case SCTP_CID_RECONF:
2015 			if (asoc->reconf_enable &&
2016 			    !asoc->peer.reconf_capable)
2017 				asoc->peer.reconf_capable = 1;
2018 			break;
2019 		case SCTP_CID_FWD_TSN:
2020 			if (asoc->prsctp_enable && !asoc->peer.prsctp_capable)
2021 				asoc->peer.prsctp_capable = 1;
2022 			break;
2023 		case SCTP_CID_AUTH:
2024 			/* if the peer reports AUTH, assume that he
2025 			 * supports AUTH.
2026 			 */
2027 			if (asoc->ep->auth_enable)
2028 				asoc->peer.auth_capable = 1;
2029 			break;
2030 		case SCTP_CID_ASCONF:
2031 		case SCTP_CID_ASCONF_ACK:
2032 			if (net->sctp.addip_enable)
2033 				asoc->peer.asconf_capable = 1;
2034 			break;
2035 		default:
2036 			break;
2037 		}
2038 	}
2039 }
2040 
2041 /* RFC 3.2.1 & the Implementers Guide 2.2.
2042  *
2043  * The Parameter Types are encoded such that the
2044  * highest-order two bits specify the action that must be
2045  * taken if the processing endpoint does not recognize the
2046  * Parameter Type.
2047  *
2048  * 00 - Stop processing this parameter; do not process any further
2049  * 	parameters within this chunk
2050  *
2051  * 01 - Stop processing this parameter, do not process any further
2052  *	parameters within this chunk, and report the unrecognized
2053  *	parameter in an 'Unrecognized Parameter' ERROR chunk.
2054  *
2055  * 10 - Skip this parameter and continue processing.
2056  *
2057  * 11 - Skip this parameter and continue processing but
2058  *	report the unrecognized parameter in an
2059  *	'Unrecognized Parameter' ERROR chunk.
2060  *
2061  * Return value:
2062  * 	SCTP_IERROR_NO_ERROR - continue with the chunk
2063  * 	SCTP_IERROR_ERROR    - stop and report an error.
2064  * 	SCTP_IERROR_NOMEME   - out of memory.
2065  */
2066 static enum sctp_ierror sctp_process_unk_param(
2067 					const struct sctp_association *asoc,
2068 					union sctp_params param,
2069 					struct sctp_chunk *chunk,
2070 					struct sctp_chunk **errp)
2071 {
2072 	int retval = SCTP_IERROR_NO_ERROR;
2073 
2074 	switch (param.p->type & SCTP_PARAM_ACTION_MASK) {
2075 	case SCTP_PARAM_ACTION_DISCARD:
2076 		retval =  SCTP_IERROR_ERROR;
2077 		break;
2078 	case SCTP_PARAM_ACTION_SKIP:
2079 		break;
2080 	case SCTP_PARAM_ACTION_DISCARD_ERR:
2081 		retval =  SCTP_IERROR_ERROR;
2082 		/* Fall through */
2083 	case SCTP_PARAM_ACTION_SKIP_ERR:
2084 		/* Make an ERROR chunk, preparing enough room for
2085 		 * returning multiple unknown parameters.
2086 		 */
2087 		if (NULL == *errp)
2088 			*errp = sctp_make_op_error_fixed(asoc, chunk);
2089 
2090 		if (*errp) {
2091 			if (!sctp_init_cause_fixed(*errp, SCTP_ERROR_UNKNOWN_PARAM,
2092 					SCTP_PAD4(ntohs(param.p->length))))
2093 				sctp_addto_chunk_fixed(*errp,
2094 						SCTP_PAD4(ntohs(param.p->length)),
2095 						param.v);
2096 		} else {
2097 			/* If there is no memory for generating the ERROR
2098 			 * report as specified, an ABORT will be triggered
2099 			 * to the peer and the association won't be
2100 			 * established.
2101 			 */
2102 			retval = SCTP_IERROR_NOMEM;
2103 		}
2104 		break;
2105 	default:
2106 		break;
2107 	}
2108 
2109 	return retval;
2110 }
2111 
2112 /* Verify variable length parameters
2113  * Return values:
2114  * 	SCTP_IERROR_ABORT - trigger an ABORT
2115  * 	SCTP_IERROR_NOMEM - out of memory (abort)
2116  *	SCTP_IERROR_ERROR - stop processing, trigger an ERROR
2117  * 	SCTP_IERROR_NO_ERROR - continue with the chunk
2118  */
2119 static enum sctp_ierror sctp_verify_param(struct net *net,
2120 					  const struct sctp_endpoint *ep,
2121 					  const struct sctp_association *asoc,
2122 					  union sctp_params param,
2123 					  enum sctp_cid cid,
2124 					  struct sctp_chunk *chunk,
2125 					  struct sctp_chunk **err_chunk)
2126 {
2127 	struct sctp_hmac_algo_param *hmacs;
2128 	int retval = SCTP_IERROR_NO_ERROR;
2129 	__u16 n_elt, id = 0;
2130 	int i;
2131 
2132 	/* FIXME - This routine is not looking at each parameter per the
2133 	 * chunk type, i.e., unrecognized parameters should be further
2134 	 * identified based on the chunk id.
2135 	 */
2136 
2137 	switch (param.p->type) {
2138 	case SCTP_PARAM_IPV4_ADDRESS:
2139 	case SCTP_PARAM_IPV6_ADDRESS:
2140 	case SCTP_PARAM_COOKIE_PRESERVATIVE:
2141 	case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2142 	case SCTP_PARAM_STATE_COOKIE:
2143 	case SCTP_PARAM_HEARTBEAT_INFO:
2144 	case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2145 	case SCTP_PARAM_ECN_CAPABLE:
2146 	case SCTP_PARAM_ADAPTATION_LAYER_IND:
2147 		break;
2148 
2149 	case SCTP_PARAM_SUPPORTED_EXT:
2150 		if (!sctp_verify_ext_param(net, param))
2151 			return SCTP_IERROR_ABORT;
2152 		break;
2153 
2154 	case SCTP_PARAM_SET_PRIMARY:
2155 		if (net->sctp.addip_enable)
2156 			break;
2157 		goto fallthrough;
2158 
2159 	case SCTP_PARAM_HOST_NAME_ADDRESS:
2160 		/* Tell the peer, we won't support this param.  */
2161 		sctp_process_hn_param(asoc, param, chunk, err_chunk);
2162 		retval = SCTP_IERROR_ABORT;
2163 		break;
2164 
2165 	case SCTP_PARAM_FWD_TSN_SUPPORT:
2166 		if (ep->prsctp_enable)
2167 			break;
2168 		goto fallthrough;
2169 
2170 	case SCTP_PARAM_RANDOM:
2171 		if (!ep->auth_enable)
2172 			goto fallthrough;
2173 
2174 		/* SCTP-AUTH: Secion 6.1
2175 		 * If the random number is not 32 byte long the association
2176 		 * MUST be aborted.  The ABORT chunk SHOULD contain the error
2177 		 * cause 'Protocol Violation'.
2178 		 */
2179 		if (SCTP_AUTH_RANDOM_LENGTH !=
2180 			ntohs(param.p->length) - sizeof(struct sctp_paramhdr)) {
2181 			sctp_process_inv_paramlength(asoc, param.p,
2182 							chunk, err_chunk);
2183 			retval = SCTP_IERROR_ABORT;
2184 		}
2185 		break;
2186 
2187 	case SCTP_PARAM_CHUNKS:
2188 		if (!ep->auth_enable)
2189 			goto fallthrough;
2190 
2191 		/* SCTP-AUTH: Section 3.2
2192 		 * The CHUNKS parameter MUST be included once in the INIT or
2193 		 *  INIT-ACK chunk if the sender wants to receive authenticated
2194 		 *  chunks.  Its maximum length is 260 bytes.
2195 		 */
2196 		if (260 < ntohs(param.p->length)) {
2197 			sctp_process_inv_paramlength(asoc, param.p,
2198 						     chunk, err_chunk);
2199 			retval = SCTP_IERROR_ABORT;
2200 		}
2201 		break;
2202 
2203 	case SCTP_PARAM_HMAC_ALGO:
2204 		if (!ep->auth_enable)
2205 			goto fallthrough;
2206 
2207 		hmacs = (struct sctp_hmac_algo_param *)param.p;
2208 		n_elt = (ntohs(param.p->length) -
2209 			 sizeof(struct sctp_paramhdr)) >> 1;
2210 
2211 		/* SCTP-AUTH: Section 6.1
2212 		 * The HMAC algorithm based on SHA-1 MUST be supported and
2213 		 * included in the HMAC-ALGO parameter.
2214 		 */
2215 		for (i = 0; i < n_elt; i++) {
2216 			id = ntohs(hmacs->hmac_ids[i]);
2217 
2218 			if (id == SCTP_AUTH_HMAC_ID_SHA1)
2219 				break;
2220 		}
2221 
2222 		if (id != SCTP_AUTH_HMAC_ID_SHA1) {
2223 			sctp_process_inv_paramlength(asoc, param.p, chunk,
2224 						     err_chunk);
2225 			retval = SCTP_IERROR_ABORT;
2226 		}
2227 		break;
2228 fallthrough:
2229 	default:
2230 		pr_debug("%s: unrecognized param:%d for chunk:%d\n",
2231 			 __func__, ntohs(param.p->type), cid);
2232 
2233 		retval = sctp_process_unk_param(asoc, param, chunk, err_chunk);
2234 		break;
2235 	}
2236 	return retval;
2237 }
2238 
2239 /* Verify the INIT packet before we process it.  */
2240 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
2241 		     const struct sctp_association *asoc, enum sctp_cid cid,
2242 		     struct sctp_init_chunk *peer_init,
2243 		     struct sctp_chunk *chunk, struct sctp_chunk **errp)
2244 {
2245 	union sctp_params param;
2246 	bool has_cookie = false;
2247 	int result;
2248 
2249 	/* Check for missing mandatory parameters. Note: Initial TSN is
2250 	 * also mandatory, but is not checked here since the valid range
2251 	 * is 0..2**32-1. RFC4960, section 3.3.3.
2252 	 */
2253 	if (peer_init->init_hdr.num_outbound_streams == 0 ||
2254 	    peer_init->init_hdr.num_inbound_streams == 0 ||
2255 	    peer_init->init_hdr.init_tag == 0 ||
2256 	    ntohl(peer_init->init_hdr.a_rwnd) < SCTP_DEFAULT_MINWINDOW)
2257 		return sctp_process_inv_mandatory(asoc, chunk, errp);
2258 
2259 	sctp_walk_params(param, peer_init, init_hdr.params) {
2260 		if (param.p->type == SCTP_PARAM_STATE_COOKIE)
2261 			has_cookie = true;
2262 	}
2263 
2264 	/* There is a possibility that a parameter length was bad and
2265 	 * in that case we would have stoped walking the parameters.
2266 	 * The current param.p would point at the bad one.
2267 	 * Current consensus on the mailing list is to generate a PROTOCOL
2268 	 * VIOLATION error.  We build the ERROR chunk here and let the normal
2269 	 * error handling code build and send the packet.
2270 	 */
2271 	if (param.v != (void *)chunk->chunk_end)
2272 		return sctp_process_inv_paramlength(asoc, param.p, chunk, errp);
2273 
2274 	/* The only missing mandatory param possible today is
2275 	 * the state cookie for an INIT-ACK chunk.
2276 	 */
2277 	if ((SCTP_CID_INIT_ACK == cid) && !has_cookie)
2278 		return sctp_process_missing_param(asoc, SCTP_PARAM_STATE_COOKIE,
2279 						  chunk, errp);
2280 
2281 	/* Verify all the variable length parameters */
2282 	sctp_walk_params(param, peer_init, init_hdr.params) {
2283 		result = sctp_verify_param(net, ep, asoc, param, cid,
2284 					   chunk, errp);
2285 		switch (result) {
2286 		case SCTP_IERROR_ABORT:
2287 		case SCTP_IERROR_NOMEM:
2288 			return 0;
2289 		case SCTP_IERROR_ERROR:
2290 			return 1;
2291 		case SCTP_IERROR_NO_ERROR:
2292 		default:
2293 			break;
2294 		}
2295 
2296 	} /* for (loop through all parameters) */
2297 
2298 	return 1;
2299 }
2300 
2301 /* Unpack the parameters in an INIT packet into an association.
2302  * Returns 0 on failure, else success.
2303  * FIXME:  This is an association method.
2304  */
2305 int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,
2306 		      const union sctp_addr *peer_addr,
2307 		      struct sctp_init_chunk *peer_init, gfp_t gfp)
2308 {
2309 	struct net *net = sock_net(asoc->base.sk);
2310 	struct sctp_transport *transport;
2311 	struct list_head *pos, *temp;
2312 	union sctp_params param;
2313 	union sctp_addr addr;
2314 	struct sctp_af *af;
2315 	int src_match = 0;
2316 	char *cookie;
2317 
2318 	/* We must include the address that the INIT packet came from.
2319 	 * This is the only address that matters for an INIT packet.
2320 	 * When processing a COOKIE ECHO, we retrieve the from address
2321 	 * of the INIT from the cookie.
2322 	 */
2323 
2324 	/* This implementation defaults to making the first transport
2325 	 * added as the primary transport.  The source address seems to
2326 	 * be a a better choice than any of the embedded addresses.
2327 	 */
2328 	if (!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
2329 		goto nomem;
2330 
2331 	if (sctp_cmp_addr_exact(sctp_source(chunk), peer_addr))
2332 		src_match = 1;
2333 
2334 	/* Process the initialization parameters.  */
2335 	sctp_walk_params(param, peer_init, init_hdr.params) {
2336 		if (!src_match && (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
2337 		    param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
2338 			af = sctp_get_af_specific(param_type2af(param.p->type));
2339 			af->from_addr_param(&addr, param.addr,
2340 					    chunk->sctp_hdr->source, 0);
2341 			if (sctp_cmp_addr_exact(sctp_source(chunk), &addr))
2342 				src_match = 1;
2343 		}
2344 
2345 		if (!sctp_process_param(asoc, param, peer_addr, gfp))
2346 			goto clean_up;
2347 	}
2348 
2349 	/* source address of chunk may not match any valid address */
2350 	if (!src_match)
2351 		goto clean_up;
2352 
2353 	/* AUTH: After processing the parameters, make sure that we
2354 	 * have all the required info to potentially do authentications.
2355 	 */
2356 	if (asoc->peer.auth_capable && (!asoc->peer.peer_random ||
2357 					!asoc->peer.peer_hmacs))
2358 		asoc->peer.auth_capable = 0;
2359 
2360 	/* In a non-backward compatible mode, if the peer claims
2361 	 * support for ADD-IP but not AUTH,  the ADD-IP spec states
2362 	 * that we MUST ABORT the association. Section 6.  The section
2363 	 * also give us an option to silently ignore the packet, which
2364 	 * is what we'll do here.
2365 	 */
2366 	if (!net->sctp.addip_noauth &&
2367 	     (asoc->peer.asconf_capable && !asoc->peer.auth_capable)) {
2368 		asoc->peer.addip_disabled_mask |= (SCTP_PARAM_ADD_IP |
2369 						  SCTP_PARAM_DEL_IP |
2370 						  SCTP_PARAM_SET_PRIMARY);
2371 		asoc->peer.asconf_capable = 0;
2372 		goto clean_up;
2373 	}
2374 
2375 	/* Walk list of transports, removing transports in the UNKNOWN state. */
2376 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2377 		transport = list_entry(pos, struct sctp_transport, transports);
2378 		if (transport->state == SCTP_UNKNOWN) {
2379 			sctp_assoc_rm_peer(asoc, transport);
2380 		}
2381 	}
2382 
2383 	/* The fixed INIT headers are always in network byte
2384 	 * order.
2385 	 */
2386 	asoc->peer.i.init_tag =
2387 		ntohl(peer_init->init_hdr.init_tag);
2388 	asoc->peer.i.a_rwnd =
2389 		ntohl(peer_init->init_hdr.a_rwnd);
2390 	asoc->peer.i.num_outbound_streams =
2391 		ntohs(peer_init->init_hdr.num_outbound_streams);
2392 	asoc->peer.i.num_inbound_streams =
2393 		ntohs(peer_init->init_hdr.num_inbound_streams);
2394 	asoc->peer.i.initial_tsn =
2395 		ntohl(peer_init->init_hdr.initial_tsn);
2396 
2397 	asoc->strreset_inseq = asoc->peer.i.initial_tsn;
2398 
2399 	/* Apply the upper bounds for output streams based on peer's
2400 	 * number of inbound streams.
2401 	 */
2402 	if (asoc->c.sinit_num_ostreams  >
2403 	    ntohs(peer_init->init_hdr.num_inbound_streams)) {
2404 		asoc->c.sinit_num_ostreams =
2405 			ntohs(peer_init->init_hdr.num_inbound_streams);
2406 	}
2407 
2408 	if (asoc->c.sinit_max_instreams >
2409 	    ntohs(peer_init->init_hdr.num_outbound_streams)) {
2410 		asoc->c.sinit_max_instreams =
2411 			ntohs(peer_init->init_hdr.num_outbound_streams);
2412 	}
2413 
2414 	/* Copy Initiation tag from INIT to VT_peer in cookie.   */
2415 	asoc->c.peer_vtag = asoc->peer.i.init_tag;
2416 
2417 	/* Peer Rwnd   : Current calculated value of the peer's rwnd.  */
2418 	asoc->peer.rwnd = asoc->peer.i.a_rwnd;
2419 
2420 	/* Copy cookie in case we need to resend COOKIE-ECHO. */
2421 	cookie = asoc->peer.cookie;
2422 	if (cookie) {
2423 		asoc->peer.cookie = kmemdup(cookie, asoc->peer.cookie_len, gfp);
2424 		if (!asoc->peer.cookie)
2425 			goto clean_up;
2426 	}
2427 
2428 	/* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily
2429 	 * high (for example, implementations MAY use the size of the receiver
2430 	 * advertised window).
2431 	 */
2432 	list_for_each_entry(transport, &asoc->peer.transport_addr_list,
2433 			transports) {
2434 		transport->ssthresh = asoc->peer.i.a_rwnd;
2435 	}
2436 
2437 	/* Set up the TSN tracking pieces.  */
2438 	if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
2439 				asoc->peer.i.initial_tsn, gfp))
2440 		goto clean_up;
2441 
2442 	/* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
2443 	 *
2444 	 * The stream sequence number in all the streams shall start
2445 	 * from 0 when the association is established.  Also, when the
2446 	 * stream sequence number reaches the value 65535 the next
2447 	 * stream sequence number shall be set to 0.
2448 	 */
2449 
2450 	if (sctp_stream_init(&asoc->stream, asoc->c.sinit_num_ostreams,
2451 			     asoc->c.sinit_max_instreams, gfp))
2452 		goto clean_up;
2453 
2454 	if (!asoc->temp && sctp_assoc_set_id(asoc, gfp))
2455 		goto clean_up;
2456 
2457 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
2458 	 *
2459 	 * When an endpoint has an ASCONF signaled change to be sent to the
2460 	 * remote endpoint it should do the following:
2461 	 * ...
2462 	 * A2) A serial number should be assigned to the Chunk. The serial
2463 	 * number should be a monotonically increasing number. All serial
2464 	 * numbers are defined to be initialized at the start of the
2465 	 * association to the same value as the Initial TSN.
2466 	 */
2467 	asoc->peer.addip_serial = asoc->peer.i.initial_tsn - 1;
2468 	return 1;
2469 
2470 clean_up:
2471 	/* Release the transport structures. */
2472 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2473 		transport = list_entry(pos, struct sctp_transport, transports);
2474 		if (transport->state != SCTP_ACTIVE)
2475 			sctp_assoc_rm_peer(asoc, transport);
2476 	}
2477 
2478 nomem:
2479 	return 0;
2480 }
2481 
2482 
2483 /* Update asoc with the option described in param.
2484  *
2485  * RFC2960 3.3.2.1 Optional/Variable Length Parameters in INIT
2486  *
2487  * asoc is the association to update.
2488  * param is the variable length parameter to use for update.
2489  * cid tells us if this is an INIT, INIT ACK or COOKIE ECHO.
2490  * If the current packet is an INIT we want to minimize the amount of
2491  * work we do.  In particular, we should not build transport
2492  * structures for the addresses.
2493  */
2494 static int sctp_process_param(struct sctp_association *asoc,
2495 			      union sctp_params param,
2496 			      const union sctp_addr *peer_addr,
2497 			      gfp_t gfp)
2498 {
2499 	struct net *net = sock_net(asoc->base.sk);
2500 	struct sctp_endpoint *ep = asoc->ep;
2501 	union sctp_addr_param *addr_param;
2502 	struct sctp_transport *t;
2503 	enum sctp_scope scope;
2504 	union sctp_addr addr;
2505 	struct sctp_af *af;
2506 	int retval = 1, i;
2507 	u32 stale;
2508 	__u16 sat;
2509 
2510 	/* We maintain all INIT parameters in network byte order all the
2511 	 * time.  This allows us to not worry about whether the parameters
2512 	 * came from a fresh INIT, and INIT ACK, or were stored in a cookie.
2513 	 */
2514 	switch (param.p->type) {
2515 	case SCTP_PARAM_IPV6_ADDRESS:
2516 		if (PF_INET6 != asoc->base.sk->sk_family)
2517 			break;
2518 		goto do_addr_param;
2519 
2520 	case SCTP_PARAM_IPV4_ADDRESS:
2521 		/* v4 addresses are not allowed on v6-only socket */
2522 		if (ipv6_only_sock(asoc->base.sk))
2523 			break;
2524 do_addr_param:
2525 		af = sctp_get_af_specific(param_type2af(param.p->type));
2526 		af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
2527 		scope = sctp_scope(peer_addr);
2528 		if (sctp_in_scope(net, &addr, scope))
2529 			if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
2530 				return 0;
2531 		break;
2532 
2533 	case SCTP_PARAM_COOKIE_PRESERVATIVE:
2534 		if (!net->sctp.cookie_preserve_enable)
2535 			break;
2536 
2537 		stale = ntohl(param.life->lifespan_increment);
2538 
2539 		/* Suggested Cookie Life span increment's unit is msec,
2540 		 * (1/1000sec).
2541 		 */
2542 		asoc->cookie_life = ktime_add_ms(asoc->cookie_life, stale);
2543 		break;
2544 
2545 	case SCTP_PARAM_HOST_NAME_ADDRESS:
2546 		pr_debug("%s: unimplemented SCTP_HOST_NAME_ADDRESS\n", __func__);
2547 		break;
2548 
2549 	case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2550 		/* Turn off the default values first so we'll know which
2551 		 * ones are really set by the peer.
2552 		 */
2553 		asoc->peer.ipv4_address = 0;
2554 		asoc->peer.ipv6_address = 0;
2555 
2556 		/* Assume that peer supports the address family
2557 		 * by which it sends a packet.
2558 		 */
2559 		if (peer_addr->sa.sa_family == AF_INET6)
2560 			asoc->peer.ipv6_address = 1;
2561 		else if (peer_addr->sa.sa_family == AF_INET)
2562 			asoc->peer.ipv4_address = 1;
2563 
2564 		/* Cycle through address types; avoid divide by 0. */
2565 		sat = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
2566 		if (sat)
2567 			sat /= sizeof(__u16);
2568 
2569 		for (i = 0; i < sat; ++i) {
2570 			switch (param.sat->types[i]) {
2571 			case SCTP_PARAM_IPV4_ADDRESS:
2572 				asoc->peer.ipv4_address = 1;
2573 				break;
2574 
2575 			case SCTP_PARAM_IPV6_ADDRESS:
2576 				if (PF_INET6 == asoc->base.sk->sk_family)
2577 					asoc->peer.ipv6_address = 1;
2578 				break;
2579 
2580 			case SCTP_PARAM_HOST_NAME_ADDRESS:
2581 				asoc->peer.hostname_address = 1;
2582 				break;
2583 
2584 			default: /* Just ignore anything else.  */
2585 				break;
2586 			}
2587 		}
2588 		break;
2589 
2590 	case SCTP_PARAM_STATE_COOKIE:
2591 		asoc->peer.cookie_len =
2592 			ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
2593 		asoc->peer.cookie = param.cookie->body;
2594 		break;
2595 
2596 	case SCTP_PARAM_HEARTBEAT_INFO:
2597 		/* Would be odd to receive, but it causes no problems. */
2598 		break;
2599 
2600 	case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2601 		/* Rejected during verify stage. */
2602 		break;
2603 
2604 	case SCTP_PARAM_ECN_CAPABLE:
2605 		asoc->peer.ecn_capable = 1;
2606 		break;
2607 
2608 	case SCTP_PARAM_ADAPTATION_LAYER_IND:
2609 		asoc->peer.adaptation_ind = ntohl(param.aind->adaptation_ind);
2610 		break;
2611 
2612 	case SCTP_PARAM_SET_PRIMARY:
2613 		if (!net->sctp.addip_enable)
2614 			goto fall_through;
2615 
2616 		addr_param = param.v + sizeof(struct sctp_addip_param);
2617 
2618 		af = sctp_get_af_specific(param_type2af(addr_param->p.type));
2619 		if (af == NULL)
2620 			break;
2621 
2622 		af->from_addr_param(&addr, addr_param,
2623 				    htons(asoc->peer.port), 0);
2624 
2625 		/* if the address is invalid, we can't process it.
2626 		 * XXX: see spec for what to do.
2627 		 */
2628 		if (!af->addr_valid(&addr, NULL, NULL))
2629 			break;
2630 
2631 		t = sctp_assoc_lookup_paddr(asoc, &addr);
2632 		if (!t)
2633 			break;
2634 
2635 		sctp_assoc_set_primary(asoc, t);
2636 		break;
2637 
2638 	case SCTP_PARAM_SUPPORTED_EXT:
2639 		sctp_process_ext_param(asoc, param);
2640 		break;
2641 
2642 	case SCTP_PARAM_FWD_TSN_SUPPORT:
2643 		if (asoc->prsctp_enable) {
2644 			asoc->peer.prsctp_capable = 1;
2645 			break;
2646 		}
2647 		/* Fall Through */
2648 		goto fall_through;
2649 
2650 	case SCTP_PARAM_RANDOM:
2651 		if (!ep->auth_enable)
2652 			goto fall_through;
2653 
2654 		/* Save peer's random parameter */
2655 		asoc->peer.peer_random = kmemdup(param.p,
2656 					    ntohs(param.p->length), gfp);
2657 		if (!asoc->peer.peer_random) {
2658 			retval = 0;
2659 			break;
2660 		}
2661 		break;
2662 
2663 	case SCTP_PARAM_HMAC_ALGO:
2664 		if (!ep->auth_enable)
2665 			goto fall_through;
2666 
2667 		/* Save peer's HMAC list */
2668 		asoc->peer.peer_hmacs = kmemdup(param.p,
2669 					    ntohs(param.p->length), gfp);
2670 		if (!asoc->peer.peer_hmacs) {
2671 			retval = 0;
2672 			break;
2673 		}
2674 
2675 		/* Set the default HMAC the peer requested*/
2676 		sctp_auth_asoc_set_default_hmac(asoc, param.hmac_algo);
2677 		break;
2678 
2679 	case SCTP_PARAM_CHUNKS:
2680 		if (!ep->auth_enable)
2681 			goto fall_through;
2682 
2683 		asoc->peer.peer_chunks = kmemdup(param.p,
2684 					    ntohs(param.p->length), gfp);
2685 		if (!asoc->peer.peer_chunks)
2686 			retval = 0;
2687 		break;
2688 fall_through:
2689 	default:
2690 		/* Any unrecognized parameters should have been caught
2691 		 * and handled by sctp_verify_param() which should be
2692 		 * called prior to this routine.  Simply log the error
2693 		 * here.
2694 		 */
2695 		pr_debug("%s: ignoring param:%d for association:%p.\n",
2696 			 __func__, ntohs(param.p->type), asoc);
2697 		break;
2698 	}
2699 
2700 	return retval;
2701 }
2702 
2703 /* Select a new verification tag.  */
2704 __u32 sctp_generate_tag(const struct sctp_endpoint *ep)
2705 {
2706 	/* I believe that this random number generator complies with RFC1750.
2707 	 * A tag of 0 is reserved for special cases (e.g. INIT).
2708 	 */
2709 	__u32 x;
2710 
2711 	do {
2712 		get_random_bytes(&x, sizeof(__u32));
2713 	} while (x == 0);
2714 
2715 	return x;
2716 }
2717 
2718 /* Select an initial TSN to send during startup.  */
2719 __u32 sctp_generate_tsn(const struct sctp_endpoint *ep)
2720 {
2721 	__u32 retval;
2722 
2723 	get_random_bytes(&retval, sizeof(__u32));
2724 	return retval;
2725 }
2726 
2727 /*
2728  * ADDIP 3.1.1 Address Configuration Change Chunk (ASCONF)
2729  *      0                   1                   2                   3
2730  *      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
2731  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2732  *     | Type = 0xC1   |  Chunk Flags  |      Chunk Length             |
2733  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2734  *     |                       Serial Number                           |
2735  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2736  *     |                    Address Parameter                          |
2737  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2738  *     |                     ASCONF Parameter #1                       |
2739  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2740  *     \                                                               \
2741  *     /                             ....                              /
2742  *     \                                                               \
2743  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2744  *     |                     ASCONF Parameter #N                       |
2745  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2746  *
2747  * Address Parameter and other parameter will not be wrapped in this function
2748  */
2749 static struct sctp_chunk *sctp_make_asconf(struct sctp_association *asoc,
2750 					   union sctp_addr *addr,
2751 					   int vparam_len)
2752 {
2753 	struct sctp_addiphdr asconf;
2754 	struct sctp_chunk *retval;
2755 	int length = sizeof(asconf) + vparam_len;
2756 	union sctp_addr_param addrparam;
2757 	int addrlen;
2758 	struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
2759 
2760 	addrlen = af->to_addr_param(addr, &addrparam);
2761 	if (!addrlen)
2762 		return NULL;
2763 	length += addrlen;
2764 
2765 	/* Create the chunk.  */
2766 	retval = sctp_make_control(asoc, SCTP_CID_ASCONF, 0, length,
2767 				   GFP_ATOMIC);
2768 	if (!retval)
2769 		return NULL;
2770 
2771 	asconf.serial = htonl(asoc->addip_serial++);
2772 
2773 	retval->subh.addip_hdr =
2774 		sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2775 	retval->param_hdr.v =
2776 		sctp_addto_chunk(retval, addrlen, &addrparam);
2777 
2778 	return retval;
2779 }
2780 
2781 /* ADDIP
2782  * 3.2.1 Add IP Address
2783  * 	0                   1                   2                   3
2784  * 	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
2785  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2786  *     |        Type = 0xC001          |    Length = Variable          |
2787  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2788  *     |               ASCONF-Request Correlation ID                   |
2789  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2790  *     |                       Address Parameter                       |
2791  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2792  *
2793  * 3.2.2 Delete IP Address
2794  * 	0                   1                   2                   3
2795  * 	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
2796  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2797  *     |        Type = 0xC002          |    Length = Variable          |
2798  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2799  *     |               ASCONF-Request Correlation ID                   |
2800  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2801  *     |                       Address Parameter                       |
2802  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2803  *
2804  */
2805 struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *asoc,
2806 					      union sctp_addr *laddr,
2807 					      struct sockaddr *addrs,
2808 					      int addrcnt, __be16 flags)
2809 {
2810 	union sctp_addr_param addr_param;
2811 	struct sctp_addip_param	param;
2812 	int paramlen = sizeof(param);
2813 	struct sctp_chunk *retval;
2814 	int addr_param_len = 0;
2815 	union sctp_addr *addr;
2816 	int totallen = 0, i;
2817 	int del_pickup = 0;
2818 	struct sctp_af *af;
2819 	void *addr_buf;
2820 
2821 	/* Get total length of all the address parameters. */
2822 	addr_buf = addrs;
2823 	for (i = 0; i < addrcnt; i++) {
2824 		addr = addr_buf;
2825 		af = sctp_get_af_specific(addr->v4.sin_family);
2826 		addr_param_len = af->to_addr_param(addr, &addr_param);
2827 
2828 		totallen += paramlen;
2829 		totallen += addr_param_len;
2830 
2831 		addr_buf += af->sockaddr_len;
2832 		if (asoc->asconf_addr_del_pending && !del_pickup) {
2833 			/* reuse the parameter length from the same scope one */
2834 			totallen += paramlen;
2835 			totallen += addr_param_len;
2836 			del_pickup = 1;
2837 
2838 			pr_debug("%s: picked same-scope del_pending addr, "
2839 				 "totallen for all addresses is %d\n",
2840 				 __func__, totallen);
2841 		}
2842 	}
2843 
2844 	/* Create an asconf chunk with the required length. */
2845 	retval = sctp_make_asconf(asoc, laddr, totallen);
2846 	if (!retval)
2847 		return NULL;
2848 
2849 	/* Add the address parameters to the asconf chunk. */
2850 	addr_buf = addrs;
2851 	for (i = 0; i < addrcnt; i++) {
2852 		addr = addr_buf;
2853 		af = sctp_get_af_specific(addr->v4.sin_family);
2854 		addr_param_len = af->to_addr_param(addr, &addr_param);
2855 		param.param_hdr.type = flags;
2856 		param.param_hdr.length = htons(paramlen + addr_param_len);
2857 		param.crr_id = htonl(i);
2858 
2859 		sctp_addto_chunk(retval, paramlen, &param);
2860 		sctp_addto_chunk(retval, addr_param_len, &addr_param);
2861 
2862 		addr_buf += af->sockaddr_len;
2863 	}
2864 	if (flags == SCTP_PARAM_ADD_IP && del_pickup) {
2865 		addr = asoc->asconf_addr_del_pending;
2866 		af = sctp_get_af_specific(addr->v4.sin_family);
2867 		addr_param_len = af->to_addr_param(addr, &addr_param);
2868 		param.param_hdr.type = SCTP_PARAM_DEL_IP;
2869 		param.param_hdr.length = htons(paramlen + addr_param_len);
2870 		param.crr_id = htonl(i);
2871 
2872 		sctp_addto_chunk(retval, paramlen, &param);
2873 		sctp_addto_chunk(retval, addr_param_len, &addr_param);
2874 	}
2875 	return retval;
2876 }
2877 
2878 /* ADDIP
2879  * 3.2.4 Set Primary IP Address
2880  *	0                   1                   2                   3
2881  *	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
2882  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2883  *     |        Type =0xC004           |    Length = Variable          |
2884  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2885  *     |               ASCONF-Request Correlation ID                   |
2886  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2887  *     |                       Address Parameter                       |
2888  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2889  *
2890  * Create an ASCONF chunk with Set Primary IP address parameter.
2891  */
2892 struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
2893 					     union sctp_addr *addr)
2894 {
2895 	struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
2896 	union sctp_addr_param addrparam;
2897 	struct sctp_addip_param	param;
2898 	struct sctp_chunk *retval;
2899 	int len = sizeof(param);
2900 	int addrlen;
2901 
2902 	addrlen = af->to_addr_param(addr, &addrparam);
2903 	if (!addrlen)
2904 		return NULL;
2905 	len += addrlen;
2906 
2907 	/* Create the chunk and make asconf header. */
2908 	retval = sctp_make_asconf(asoc, addr, len);
2909 	if (!retval)
2910 		return NULL;
2911 
2912 	param.param_hdr.type = SCTP_PARAM_SET_PRIMARY;
2913 	param.param_hdr.length = htons(len);
2914 	param.crr_id = 0;
2915 
2916 	sctp_addto_chunk(retval, sizeof(param), &param);
2917 	sctp_addto_chunk(retval, addrlen, &addrparam);
2918 
2919 	return retval;
2920 }
2921 
2922 /* ADDIP 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
2923  *      0                   1                   2                   3
2924  *      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
2925  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2926  *     | Type = 0x80   |  Chunk Flags  |      Chunk Length             |
2927  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2928  *     |                       Serial Number                           |
2929  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2930  *     |                 ASCONF Parameter Response#1                   |
2931  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2932  *     \                                                               \
2933  *     /                             ....                              /
2934  *     \                                                               \
2935  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2936  *     |                 ASCONF Parameter Response#N                   |
2937  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2938  *
2939  * Create an ASCONF_ACK chunk with enough space for the parameter responses.
2940  */
2941 static struct sctp_chunk *sctp_make_asconf_ack(const struct sctp_association *asoc,
2942 					       __u32 serial, int vparam_len)
2943 {
2944 	struct sctp_addiphdr asconf;
2945 	struct sctp_chunk *retval;
2946 	int length = sizeof(asconf) + vparam_len;
2947 
2948 	/* Create the chunk.  */
2949 	retval = sctp_make_control(asoc, SCTP_CID_ASCONF_ACK, 0, length,
2950 				   GFP_ATOMIC);
2951 	if (!retval)
2952 		return NULL;
2953 
2954 	asconf.serial = htonl(serial);
2955 
2956 	retval->subh.addip_hdr =
2957 		sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2958 
2959 	return retval;
2960 }
2961 
2962 /* Add response parameters to an ASCONF_ACK chunk. */
2963 static void sctp_add_asconf_response(struct sctp_chunk *chunk, __be32 crr_id,
2964 				     __be16 err_code,
2965 				     struct sctp_addip_param *asconf_param)
2966 {
2967 	struct sctp_addip_param ack_param;
2968 	struct sctp_errhdr err_param;
2969 	int asconf_param_len = 0;
2970 	int err_param_len = 0;
2971 	__be16 response_type;
2972 
2973 	if (SCTP_ERROR_NO_ERROR == err_code) {
2974 		response_type = SCTP_PARAM_SUCCESS_REPORT;
2975 	} else {
2976 		response_type = SCTP_PARAM_ERR_CAUSE;
2977 		err_param_len = sizeof(err_param);
2978 		if (asconf_param)
2979 			asconf_param_len =
2980 				 ntohs(asconf_param->param_hdr.length);
2981 	}
2982 
2983 	/* Add Success Indication or Error Cause Indication parameter. */
2984 	ack_param.param_hdr.type = response_type;
2985 	ack_param.param_hdr.length = htons(sizeof(ack_param) +
2986 					   err_param_len +
2987 					   asconf_param_len);
2988 	ack_param.crr_id = crr_id;
2989 	sctp_addto_chunk(chunk, sizeof(ack_param), &ack_param);
2990 
2991 	if (SCTP_ERROR_NO_ERROR == err_code)
2992 		return;
2993 
2994 	/* Add Error Cause parameter. */
2995 	err_param.cause = err_code;
2996 	err_param.length = htons(err_param_len + asconf_param_len);
2997 	sctp_addto_chunk(chunk, err_param_len, &err_param);
2998 
2999 	/* Add the failed TLV copied from ASCONF chunk. */
3000 	if (asconf_param)
3001 		sctp_addto_chunk(chunk, asconf_param_len, asconf_param);
3002 }
3003 
3004 /* Process a asconf parameter. */
3005 static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
3006 					struct sctp_chunk *asconf,
3007 					struct sctp_addip_param *asconf_param)
3008 {
3009 	union sctp_addr_param *addr_param;
3010 	struct sctp_transport *peer;
3011 	union sctp_addr	addr;
3012 	struct sctp_af *af;
3013 
3014 	addr_param = (void *)asconf_param + sizeof(*asconf_param);
3015 
3016 	if (asconf_param->param_hdr.type != SCTP_PARAM_ADD_IP &&
3017 	    asconf_param->param_hdr.type != SCTP_PARAM_DEL_IP &&
3018 	    asconf_param->param_hdr.type != SCTP_PARAM_SET_PRIMARY)
3019 		return SCTP_ERROR_UNKNOWN_PARAM;
3020 
3021 	switch (addr_param->p.type) {
3022 	case SCTP_PARAM_IPV6_ADDRESS:
3023 		if (!asoc->peer.ipv6_address)
3024 			return SCTP_ERROR_DNS_FAILED;
3025 		break;
3026 	case SCTP_PARAM_IPV4_ADDRESS:
3027 		if (!asoc->peer.ipv4_address)
3028 			return SCTP_ERROR_DNS_FAILED;
3029 		break;
3030 	default:
3031 		return SCTP_ERROR_DNS_FAILED;
3032 	}
3033 
3034 	af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3035 	if (unlikely(!af))
3036 		return SCTP_ERROR_DNS_FAILED;
3037 
3038 	af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);
3039 
3040 	/* ADDIP 4.2.1  This parameter MUST NOT contain a broadcast
3041 	 * or multicast address.
3042 	 * (note: wildcard is permitted and requires special handling so
3043 	 *  make sure we check for that)
3044 	 */
3045 	if (!af->is_any(&addr) && !af->addr_valid(&addr, NULL, asconf->skb))
3046 		return SCTP_ERROR_DNS_FAILED;
3047 
3048 	switch (asconf_param->param_hdr.type) {
3049 	case SCTP_PARAM_ADD_IP:
3050 		/* Section 4.2.1:
3051 		 * If the address 0.0.0.0 or ::0 is provided, the source
3052 		 * address of the packet MUST be added.
3053 		 */
3054 		if (af->is_any(&addr))
3055 			memcpy(&addr, &asconf->source, sizeof(addr));
3056 
3057 		/* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
3058 		 * request and does not have the local resources to add this
3059 		 * new address to the association, it MUST return an Error
3060 		 * Cause TLV set to the new error code 'Operation Refused
3061 		 * Due to Resource Shortage'.
3062 		 */
3063 
3064 		peer = sctp_assoc_add_peer(asoc, &addr, GFP_ATOMIC, SCTP_UNCONFIRMED);
3065 		if (!peer)
3066 			return SCTP_ERROR_RSRC_LOW;
3067 
3068 		/* Start the heartbeat timer. */
3069 		sctp_transport_reset_hb_timer(peer);
3070 		asoc->new_transport = peer;
3071 		break;
3072 	case SCTP_PARAM_DEL_IP:
3073 		/* ADDIP 4.3 D7) If a request is received to delete the
3074 		 * last remaining IP address of a peer endpoint, the receiver
3075 		 * MUST send an Error Cause TLV with the error cause set to the
3076 		 * new error code 'Request to Delete Last Remaining IP Address'.
3077 		 */
3078 		if (asoc->peer.transport_count == 1)
3079 			return SCTP_ERROR_DEL_LAST_IP;
3080 
3081 		/* ADDIP 4.3 D8) If a request is received to delete an IP
3082 		 * address which is also the source address of the IP packet
3083 		 * which contained the ASCONF chunk, the receiver MUST reject
3084 		 * this request. To reject the request the receiver MUST send
3085 		 * an Error Cause TLV set to the new error code 'Request to
3086 		 * Delete Source IP Address'
3087 		 */
3088 		if (sctp_cmp_addr_exact(&asconf->source, &addr))
3089 			return SCTP_ERROR_DEL_SRC_IP;
3090 
3091 		/* Section 4.2.2
3092 		 * If the address 0.0.0.0 or ::0 is provided, all
3093 		 * addresses of the peer except	the source address of the
3094 		 * packet MUST be deleted.
3095 		 */
3096 		if (af->is_any(&addr)) {
3097 			sctp_assoc_set_primary(asoc, asconf->transport);
3098 			sctp_assoc_del_nonprimary_peers(asoc,
3099 							asconf->transport);
3100 			return SCTP_ERROR_NO_ERROR;
3101 		}
3102 
3103 		/* If the address is not part of the association, the
3104 		 * ASCONF-ACK with Error Cause Indication Parameter
3105 		 * which including cause of Unresolvable Address should
3106 		 * be sent.
3107 		 */
3108 		peer = sctp_assoc_lookup_paddr(asoc, &addr);
3109 		if (!peer)
3110 			return SCTP_ERROR_DNS_FAILED;
3111 
3112 		sctp_assoc_rm_peer(asoc, peer);
3113 		break;
3114 	case SCTP_PARAM_SET_PRIMARY:
3115 		/* ADDIP Section 4.2.4
3116 		 * If the address 0.0.0.0 or ::0 is provided, the receiver
3117 		 * MAY mark the source address of the packet as its
3118 		 * primary.
3119 		 */
3120 		if (af->is_any(&addr))
3121 			memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));
3122 
3123 		peer = sctp_assoc_lookup_paddr(asoc, &addr);
3124 		if (!peer)
3125 			return SCTP_ERROR_DNS_FAILED;
3126 
3127 		sctp_assoc_set_primary(asoc, peer);
3128 		break;
3129 	}
3130 
3131 	return SCTP_ERROR_NO_ERROR;
3132 }
3133 
3134 /* Verify the ASCONF packet before we process it. */
3135 bool sctp_verify_asconf(const struct sctp_association *asoc,
3136 			struct sctp_chunk *chunk, bool addr_param_needed,
3137 			struct sctp_paramhdr **errp)
3138 {
3139 	struct sctp_addip_chunk *addip;
3140 	bool addr_param_seen = false;
3141 	union sctp_params param;
3142 
3143 	addip = (struct sctp_addip_chunk *)chunk->chunk_hdr;
3144 	sctp_walk_params(param, addip, addip_hdr.params) {
3145 		size_t length = ntohs(param.p->length);
3146 
3147 		*errp = param.p;
3148 		switch (param.p->type) {
3149 		case SCTP_PARAM_ERR_CAUSE:
3150 			break;
3151 		case SCTP_PARAM_IPV4_ADDRESS:
3152 			if (length != sizeof(struct sctp_ipv4addr_param))
3153 				return false;
3154 			/* ensure there is only one addr param and it's in the
3155 			 * beginning of addip_hdr params, or we reject it.
3156 			 */
3157 			if (param.v != addip->addip_hdr.params)
3158 				return false;
3159 			addr_param_seen = true;
3160 			break;
3161 		case SCTP_PARAM_IPV6_ADDRESS:
3162 			if (length != sizeof(struct sctp_ipv6addr_param))
3163 				return false;
3164 			if (param.v != addip->addip_hdr.params)
3165 				return false;
3166 			addr_param_seen = true;
3167 			break;
3168 		case SCTP_PARAM_ADD_IP:
3169 		case SCTP_PARAM_DEL_IP:
3170 		case SCTP_PARAM_SET_PRIMARY:
3171 			/* In ASCONF chunks, these need to be first. */
3172 			if (addr_param_needed && !addr_param_seen)
3173 				return false;
3174 			length = ntohs(param.addip->param_hdr.length);
3175 			if (length < sizeof(struct sctp_addip_param) +
3176 				     sizeof(**errp))
3177 				return false;
3178 			break;
3179 		case SCTP_PARAM_SUCCESS_REPORT:
3180 		case SCTP_PARAM_ADAPTATION_LAYER_IND:
3181 			if (length != sizeof(struct sctp_addip_param))
3182 				return false;
3183 			break;
3184 		default:
3185 			/* This is unkown to us, reject! */
3186 			return false;
3187 		}
3188 	}
3189 
3190 	/* Remaining sanity checks. */
3191 	if (addr_param_needed && !addr_param_seen)
3192 		return false;
3193 	if (!addr_param_needed && addr_param_seen)
3194 		return false;
3195 	if (param.v != chunk->chunk_end)
3196 		return false;
3197 
3198 	return true;
3199 }
3200 
3201 /* Process an incoming ASCONF chunk with the next expected serial no. and
3202  * return an ASCONF_ACK chunk to be sent in response.
3203  */
3204 struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
3205 				       struct sctp_chunk *asconf)
3206 {
3207 	union sctp_addr_param *addr_param;
3208 	struct sctp_addip_chunk *addip;
3209 	struct sctp_chunk *asconf_ack;
3210 	bool all_param_pass = true;
3211 	struct sctp_addiphdr *hdr;
3212 	int length = 0, chunk_len;
3213 	union sctp_params param;
3214 	__be16 err_code;
3215 	__u32 serial;
3216 
3217 	addip = (struct sctp_addip_chunk *)asconf->chunk_hdr;
3218 	chunk_len = ntohs(asconf->chunk_hdr->length) -
3219 		    sizeof(struct sctp_chunkhdr);
3220 	hdr = (struct sctp_addiphdr *)asconf->skb->data;
3221 	serial = ntohl(hdr->serial);
3222 
3223 	/* Skip the addiphdr and store a pointer to address parameter.  */
3224 	length = sizeof(*hdr);
3225 	addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3226 	chunk_len -= length;
3227 
3228 	/* Skip the address parameter and store a pointer to the first
3229 	 * asconf parameter.
3230 	 */
3231 	length = ntohs(addr_param->p.length);
3232 	chunk_len -= length;
3233 
3234 	/* create an ASCONF_ACK chunk.
3235 	 * Based on the definitions of parameters, we know that the size of
3236 	 * ASCONF_ACK parameters are less than or equal to the fourfold of ASCONF
3237 	 * parameters.
3238 	 */
3239 	asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 4);
3240 	if (!asconf_ack)
3241 		goto done;
3242 
3243 	/* Process the TLVs contained within the ASCONF chunk. */
3244 	sctp_walk_params(param, addip, addip_hdr.params) {
3245 		/* Skip preceeding address parameters. */
3246 		if (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
3247 		    param.p->type == SCTP_PARAM_IPV6_ADDRESS)
3248 			continue;
3249 
3250 		err_code = sctp_process_asconf_param(asoc, asconf,
3251 						     param.addip);
3252 		/* ADDIP 4.1 A7)
3253 		 * If an error response is received for a TLV parameter,
3254 		 * all TLVs with no response before the failed TLV are
3255 		 * considered successful if not reported.  All TLVs after
3256 		 * the failed response are considered unsuccessful unless
3257 		 * a specific success indication is present for the parameter.
3258 		 */
3259 		if (err_code != SCTP_ERROR_NO_ERROR)
3260 			all_param_pass = false;
3261 		if (!all_param_pass)
3262 			sctp_add_asconf_response(asconf_ack, param.addip->crr_id,
3263 						 err_code, param.addip);
3264 
3265 		/* ADDIP 4.3 D11) When an endpoint receiving an ASCONF to add
3266 		 * an IP address sends an 'Out of Resource' in its response, it
3267 		 * MUST also fail any subsequent add or delete requests bundled
3268 		 * in the ASCONF.
3269 		 */
3270 		if (err_code == SCTP_ERROR_RSRC_LOW)
3271 			goto done;
3272 	}
3273 done:
3274 	asoc->peer.addip_serial++;
3275 
3276 	/* If we are sending a new ASCONF_ACK hold a reference to it in assoc
3277 	 * after freeing the reference to old asconf ack if any.
3278 	 */
3279 	if (asconf_ack) {
3280 		sctp_chunk_hold(asconf_ack);
3281 		list_add_tail(&asconf_ack->transmitted_list,
3282 			      &asoc->asconf_ack_list);
3283 	}
3284 
3285 	return asconf_ack;
3286 }
3287 
3288 /* Process a asconf parameter that is successfully acked. */
3289 static void sctp_asconf_param_success(struct sctp_association *asoc,
3290 				      struct sctp_addip_param *asconf_param)
3291 {
3292 	struct sctp_bind_addr *bp = &asoc->base.bind_addr;
3293 	union sctp_addr_param *addr_param;
3294 	struct sctp_sockaddr_entry *saddr;
3295 	struct sctp_transport *transport;
3296 	union sctp_addr	addr;
3297 	struct sctp_af *af;
3298 
3299 	addr_param = (void *)asconf_param + sizeof(*asconf_param);
3300 
3301 	/* We have checked the packet before, so we do not check again.	*/
3302 	af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3303 	af->from_addr_param(&addr, addr_param, htons(bp->port), 0);
3304 
3305 	switch (asconf_param->param_hdr.type) {
3306 	case SCTP_PARAM_ADD_IP:
3307 		/* This is always done in BH context with a socket lock
3308 		 * held, so the list can not change.
3309 		 */
3310 		local_bh_disable();
3311 		list_for_each_entry(saddr, &bp->address_list, list) {
3312 			if (sctp_cmp_addr_exact(&saddr->a, &addr))
3313 				saddr->state = SCTP_ADDR_SRC;
3314 		}
3315 		local_bh_enable();
3316 		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3317 				transports) {
3318 			sctp_transport_dst_release(transport);
3319 		}
3320 		break;
3321 	case SCTP_PARAM_DEL_IP:
3322 		local_bh_disable();
3323 		sctp_del_bind_addr(bp, &addr);
3324 		if (asoc->asconf_addr_del_pending != NULL &&
3325 		    sctp_cmp_addr_exact(asoc->asconf_addr_del_pending, &addr)) {
3326 			kfree(asoc->asconf_addr_del_pending);
3327 			asoc->asconf_addr_del_pending = NULL;
3328 		}
3329 		local_bh_enable();
3330 		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3331 				transports) {
3332 			sctp_transport_dst_release(transport);
3333 		}
3334 		break;
3335 	default:
3336 		break;
3337 	}
3338 }
3339 
3340 /* Get the corresponding ASCONF response error code from the ASCONF_ACK chunk
3341  * for the given asconf parameter.  If there is no response for this parameter,
3342  * return the error code based on the third argument 'no_err'.
3343  * ADDIP 4.1
3344  * A7) If an error response is received for a TLV parameter, all TLVs with no
3345  * response before the failed TLV are considered successful if not reported.
3346  * All TLVs after the failed response are considered unsuccessful unless a
3347  * specific success indication is present for the parameter.
3348  */
3349 static __be16 sctp_get_asconf_response(struct sctp_chunk *asconf_ack,
3350 				       struct sctp_addip_param *asconf_param,
3351 				       int no_err)
3352 {
3353 	struct sctp_addip_param	*asconf_ack_param;
3354 	struct sctp_errhdr *err_param;
3355 	int asconf_ack_len;
3356 	__be16 err_code;
3357 	int length;
3358 
3359 	if (no_err)
3360 		err_code = SCTP_ERROR_NO_ERROR;
3361 	else
3362 		err_code = SCTP_ERROR_REQ_REFUSED;
3363 
3364 	asconf_ack_len = ntohs(asconf_ack->chunk_hdr->length) -
3365 			 sizeof(struct sctp_chunkhdr);
3366 
3367 	/* Skip the addiphdr from the asconf_ack chunk and store a pointer to
3368 	 * the first asconf_ack parameter.
3369 	 */
3370 	length = sizeof(struct sctp_addiphdr);
3371 	asconf_ack_param = (struct sctp_addip_param *)(asconf_ack->skb->data +
3372 						       length);
3373 	asconf_ack_len -= length;
3374 
3375 	while (asconf_ack_len > 0) {
3376 		if (asconf_ack_param->crr_id == asconf_param->crr_id) {
3377 			switch (asconf_ack_param->param_hdr.type) {
3378 			case SCTP_PARAM_SUCCESS_REPORT:
3379 				return SCTP_ERROR_NO_ERROR;
3380 			case SCTP_PARAM_ERR_CAUSE:
3381 				length = sizeof(*asconf_ack_param);
3382 				err_param = (void *)asconf_ack_param + length;
3383 				asconf_ack_len -= length;
3384 				if (asconf_ack_len > 0)
3385 					return err_param->cause;
3386 				else
3387 					return SCTP_ERROR_INV_PARAM;
3388 				break;
3389 			default:
3390 				return SCTP_ERROR_INV_PARAM;
3391 			}
3392 		}
3393 
3394 		length = ntohs(asconf_ack_param->param_hdr.length);
3395 		asconf_ack_param = (void *)asconf_ack_param + length;
3396 		asconf_ack_len -= length;
3397 	}
3398 
3399 	return err_code;
3400 }
3401 
3402 /* Process an incoming ASCONF_ACK chunk against the cached last ASCONF chunk. */
3403 int sctp_process_asconf_ack(struct sctp_association *asoc,
3404 			    struct sctp_chunk *asconf_ack)
3405 {
3406 	struct sctp_chunk *asconf = asoc->addip_last_asconf;
3407 	struct sctp_addip_param *asconf_param;
3408 	__be16 err_code = SCTP_ERROR_NO_ERROR;
3409 	union sctp_addr_param *addr_param;
3410 	int asconf_len = asconf->skb->len;
3411 	int all_param_pass = 0;
3412 	int length = 0;
3413 	int no_err = 1;
3414 	int retval = 0;
3415 
3416 	/* Skip the chunkhdr and addiphdr from the last asconf sent and store
3417 	 * a pointer to address parameter.
3418 	 */
3419 	length = sizeof(struct sctp_addip_chunk);
3420 	addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3421 	asconf_len -= length;
3422 
3423 	/* Skip the address parameter in the last asconf sent and store a
3424 	 * pointer to the first asconf parameter.
3425 	 */
3426 	length = ntohs(addr_param->p.length);
3427 	asconf_param = (void *)addr_param + length;
3428 	asconf_len -= length;
3429 
3430 	/* ADDIP 4.1
3431 	 * A8) If there is no response(s) to specific TLV parameter(s), and no
3432 	 * failures are indicated, then all request(s) are considered
3433 	 * successful.
3434 	 */
3435 	if (asconf_ack->skb->len == sizeof(struct sctp_addiphdr))
3436 		all_param_pass = 1;
3437 
3438 	/* Process the TLVs contained in the last sent ASCONF chunk. */
3439 	while (asconf_len > 0) {
3440 		if (all_param_pass)
3441 			err_code = SCTP_ERROR_NO_ERROR;
3442 		else {
3443 			err_code = sctp_get_asconf_response(asconf_ack,
3444 							    asconf_param,
3445 							    no_err);
3446 			if (no_err && (SCTP_ERROR_NO_ERROR != err_code))
3447 				no_err = 0;
3448 		}
3449 
3450 		switch (err_code) {
3451 		case SCTP_ERROR_NO_ERROR:
3452 			sctp_asconf_param_success(asoc, asconf_param);
3453 			break;
3454 
3455 		case SCTP_ERROR_RSRC_LOW:
3456 			retval = 1;
3457 			break;
3458 
3459 		case SCTP_ERROR_UNKNOWN_PARAM:
3460 			/* Disable sending this type of asconf parameter in
3461 			 * future.
3462 			 */
3463 			asoc->peer.addip_disabled_mask |=
3464 				asconf_param->param_hdr.type;
3465 			break;
3466 
3467 		case SCTP_ERROR_REQ_REFUSED:
3468 		case SCTP_ERROR_DEL_LAST_IP:
3469 		case SCTP_ERROR_DEL_SRC_IP:
3470 		default:
3471 			 break;
3472 		}
3473 
3474 		/* Skip the processed asconf parameter and move to the next
3475 		 * one.
3476 		 */
3477 		length = ntohs(asconf_param->param_hdr.length);
3478 		asconf_param = (void *)asconf_param + length;
3479 		asconf_len -= length;
3480 	}
3481 
3482 	if (no_err && asoc->src_out_of_asoc_ok) {
3483 		asoc->src_out_of_asoc_ok = 0;
3484 		sctp_transport_immediate_rtx(asoc->peer.primary_path);
3485 	}
3486 
3487 	/* Free the cached last sent asconf chunk. */
3488 	list_del_init(&asconf->transmitted_list);
3489 	sctp_chunk_free(asconf);
3490 	asoc->addip_last_asconf = NULL;
3491 
3492 	return retval;
3493 }
3494 
3495 /* Make a FWD TSN chunk. */
3496 struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
3497 				    __u32 new_cum_tsn, size_t nstreams,
3498 				    struct sctp_fwdtsn_skip *skiplist)
3499 {
3500 	struct sctp_chunk *retval = NULL;
3501 	struct sctp_fwdtsn_hdr ftsn_hdr;
3502 	struct sctp_fwdtsn_skip skip;
3503 	size_t hint;
3504 	int i;
3505 
3506 	hint = (nstreams + 1) * sizeof(__u32);
3507 
3508 	retval = sctp_make_control(asoc, SCTP_CID_FWD_TSN, 0, hint, GFP_ATOMIC);
3509 
3510 	if (!retval)
3511 		return NULL;
3512 
3513 	ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
3514 	retval->subh.fwdtsn_hdr =
3515 		sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
3516 
3517 	for (i = 0; i < nstreams; i++) {
3518 		skip.stream = skiplist[i].stream;
3519 		skip.ssn = skiplist[i].ssn;
3520 		sctp_addto_chunk(retval, sizeof(skip), &skip);
3521 	}
3522 
3523 	return retval;
3524 }
3525 
3526 /* RE-CONFIG 3.1 (RE-CONFIG chunk)
3527  *   0                   1                   2                   3
3528  *   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
3529  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3530  *  | Type = 130    |  Chunk Flags  |      Chunk Length             |
3531  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3532  *  \                                                               \
3533  *  /                  Re-configuration Parameter                   /
3534  *  \                                                               \
3535  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3536  *  \                                                               \
3537  *  /             Re-configuration Parameter (optional)             /
3538  *  \                                                               \
3539  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3540  */
3541 static struct sctp_chunk *sctp_make_reconf(const struct sctp_association *asoc,
3542 					   int length)
3543 {
3544 	struct sctp_reconf_chunk *reconf;
3545 	struct sctp_chunk *retval;
3546 
3547 	retval = sctp_make_control(asoc, SCTP_CID_RECONF, 0, length,
3548 				   GFP_ATOMIC);
3549 	if (!retval)
3550 		return NULL;
3551 
3552 	reconf = (struct sctp_reconf_chunk *)retval->chunk_hdr;
3553 	retval->param_hdr.v = reconf->params;
3554 
3555 	return retval;
3556 }
3557 
3558 /* RE-CONFIG 4.1 (STREAM OUT RESET)
3559  *   0                   1                   2                   3
3560  *   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
3561  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3562  *  |     Parameter Type = 13       | Parameter Length = 16 + 2 * N |
3563  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3564  *  |           Re-configuration Request Sequence Number            |
3565  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3566  *  |           Re-configuration Response Sequence Number           |
3567  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3568  *  |                Sender's Last Assigned TSN                     |
3569  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3570  *  |  Stream Number 1 (optional)   |    Stream Number 2 (optional) |
3571  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3572  *  /                            ......                             /
3573  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3574  *  |  Stream Number N-1 (optional) |    Stream Number N (optional) |
3575  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3576  *
3577  * RE-CONFIG 4.2 (STREAM IN RESET)
3578  *   0                   1                   2                   3
3579  *   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
3580  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3581  *  |     Parameter Type = 14       |  Parameter Length = 8 + 2 * N |
3582  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3583  *  |          Re-configuration Request Sequence Number             |
3584  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3585  *  |  Stream Number 1 (optional)   |    Stream Number 2 (optional) |
3586  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3587  *  /                            ......                             /
3588  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3589  *  |  Stream Number N-1 (optional) |    Stream Number N (optional) |
3590  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3591  */
3592 struct sctp_chunk *sctp_make_strreset_req(
3593 					const struct sctp_association *asoc,
3594 					__u16 stream_num, __be16 *stream_list,
3595 					bool out, bool in)
3596 {
3597 	__u16 stream_len = stream_num * sizeof(__u16);
3598 	struct sctp_strreset_outreq outreq;
3599 	struct sctp_strreset_inreq inreq;
3600 	struct sctp_chunk *retval;
3601 	__u16 outlen, inlen;
3602 
3603 	outlen = (sizeof(outreq) + stream_len) * out;
3604 	inlen = (sizeof(inreq) + stream_len) * in;
3605 
3606 	retval = sctp_make_reconf(asoc, outlen + inlen);
3607 	if (!retval)
3608 		return NULL;
3609 
3610 	if (outlen) {
3611 		outreq.param_hdr.type = SCTP_PARAM_RESET_OUT_REQUEST;
3612 		outreq.param_hdr.length = htons(outlen);
3613 		outreq.request_seq = htonl(asoc->strreset_outseq);
3614 		outreq.response_seq = htonl(asoc->strreset_inseq - 1);
3615 		outreq.send_reset_at_tsn = htonl(asoc->next_tsn - 1);
3616 
3617 		sctp_addto_chunk(retval, sizeof(outreq), &outreq);
3618 
3619 		if (stream_len)
3620 			sctp_addto_chunk(retval, stream_len, stream_list);
3621 	}
3622 
3623 	if (inlen) {
3624 		inreq.param_hdr.type = SCTP_PARAM_RESET_IN_REQUEST;
3625 		inreq.param_hdr.length = htons(inlen);
3626 		inreq.request_seq = htonl(asoc->strreset_outseq + out);
3627 
3628 		sctp_addto_chunk(retval, sizeof(inreq), &inreq);
3629 
3630 		if (stream_len)
3631 			sctp_addto_chunk(retval, stream_len, stream_list);
3632 	}
3633 
3634 	return retval;
3635 }
3636 
3637 /* RE-CONFIG 4.3 (SSN/TSN RESET ALL)
3638  *   0                   1                   2                   3
3639  *   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
3640  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3641  *  |     Parameter Type = 15       |      Parameter Length = 8     |
3642  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3643  *  |         Re-configuration Request Sequence Number              |
3644  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3645  */
3646 struct sctp_chunk *sctp_make_strreset_tsnreq(
3647 					const struct sctp_association *asoc)
3648 {
3649 	struct sctp_strreset_tsnreq tsnreq;
3650 	__u16 length = sizeof(tsnreq);
3651 	struct sctp_chunk *retval;
3652 
3653 	retval = sctp_make_reconf(asoc, length);
3654 	if (!retval)
3655 		return NULL;
3656 
3657 	tsnreq.param_hdr.type = SCTP_PARAM_RESET_TSN_REQUEST;
3658 	tsnreq.param_hdr.length = htons(length);
3659 	tsnreq.request_seq = htonl(asoc->strreset_outseq);
3660 
3661 	sctp_addto_chunk(retval, sizeof(tsnreq), &tsnreq);
3662 
3663 	return retval;
3664 }
3665 
3666 /* RE-CONFIG 4.5/4.6 (ADD STREAM)
3667  *   0                   1                   2                   3
3668  *   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
3669  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3670  *  |     Parameter Type = 17       |      Parameter Length = 12    |
3671  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3672  *  |          Re-configuration Request Sequence Number             |
3673  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3674  *  |      Number of new streams    |         Reserved              |
3675  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3676  */
3677 struct sctp_chunk *sctp_make_strreset_addstrm(
3678 					const struct sctp_association *asoc,
3679 					__u16 out, __u16 in)
3680 {
3681 	struct sctp_strreset_addstrm addstrm;
3682 	__u16 size = sizeof(addstrm);
3683 	struct sctp_chunk *retval;
3684 
3685 	retval = sctp_make_reconf(asoc, (!!out + !!in) * size);
3686 	if (!retval)
3687 		return NULL;
3688 
3689 	if (out) {
3690 		addstrm.param_hdr.type = SCTP_PARAM_RESET_ADD_OUT_STREAMS;
3691 		addstrm.param_hdr.length = htons(size);
3692 		addstrm.number_of_streams = htons(out);
3693 		addstrm.request_seq = htonl(asoc->strreset_outseq);
3694 		addstrm.reserved = 0;
3695 
3696 		sctp_addto_chunk(retval, size, &addstrm);
3697 	}
3698 
3699 	if (in) {
3700 		addstrm.param_hdr.type = SCTP_PARAM_RESET_ADD_IN_STREAMS;
3701 		addstrm.param_hdr.length = htons(size);
3702 		addstrm.number_of_streams = htons(in);
3703 		addstrm.request_seq = htonl(asoc->strreset_outseq + !!out);
3704 		addstrm.reserved = 0;
3705 
3706 		sctp_addto_chunk(retval, size, &addstrm);
3707 	}
3708 
3709 	return retval;
3710 }
3711 
3712 /* RE-CONFIG 4.4 (RESP)
3713  *   0                   1                   2                   3
3714  *   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
3715  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3716  *  |     Parameter Type = 16       |      Parameter Length         |
3717  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3718  *  |         Re-configuration Response Sequence Number             |
3719  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3720  *  |                            Result                             |
3721  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3722  */
3723 struct sctp_chunk *sctp_make_strreset_resp(const struct sctp_association *asoc,
3724 					   __u32 result, __u32 sn)
3725 {
3726 	struct sctp_strreset_resp resp;
3727 	__u16 length = sizeof(resp);
3728 	struct sctp_chunk *retval;
3729 
3730 	retval = sctp_make_reconf(asoc, length);
3731 	if (!retval)
3732 		return NULL;
3733 
3734 	resp.param_hdr.type = SCTP_PARAM_RESET_RESPONSE;
3735 	resp.param_hdr.length = htons(length);
3736 	resp.response_seq = htonl(sn);
3737 	resp.result = htonl(result);
3738 
3739 	sctp_addto_chunk(retval, sizeof(resp), &resp);
3740 
3741 	return retval;
3742 }
3743 
3744 /* RE-CONFIG 4.4 OPTIONAL (TSNRESP)
3745  *   0                   1                   2                   3
3746  *   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
3747  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3748  *  |     Parameter Type = 16       |      Parameter Length         |
3749  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3750  *  |         Re-configuration Response Sequence Number             |
3751  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3752  *  |                            Result                             |
3753  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3754  *  |                   Sender's Next TSN (optional)                |
3755  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3756  *  |                  Receiver's Next TSN (optional)               |
3757  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3758  */
3759 struct sctp_chunk *sctp_make_strreset_tsnresp(struct sctp_association *asoc,
3760 					      __u32 result, __u32 sn,
3761 					      __u32 sender_tsn,
3762 					      __u32 receiver_tsn)
3763 {
3764 	struct sctp_strreset_resptsn tsnresp;
3765 	__u16 length = sizeof(tsnresp);
3766 	struct sctp_chunk *retval;
3767 
3768 	retval = sctp_make_reconf(asoc, length);
3769 	if (!retval)
3770 		return NULL;
3771 
3772 	tsnresp.param_hdr.type = SCTP_PARAM_RESET_RESPONSE;
3773 	tsnresp.param_hdr.length = htons(length);
3774 
3775 	tsnresp.response_seq = htonl(sn);
3776 	tsnresp.result = htonl(result);
3777 	tsnresp.senders_next_tsn = htonl(sender_tsn);
3778 	tsnresp.receivers_next_tsn = htonl(receiver_tsn);
3779 
3780 	sctp_addto_chunk(retval, sizeof(tsnresp), &tsnresp);
3781 
3782 	return retval;
3783 }
3784 
3785 bool sctp_verify_reconf(const struct sctp_association *asoc,
3786 			struct sctp_chunk *chunk,
3787 			struct sctp_paramhdr **errp)
3788 {
3789 	struct sctp_reconf_chunk *hdr;
3790 	union sctp_params param;
3791 	__be16 last = 0;
3792 	__u16 cnt = 0;
3793 
3794 	hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
3795 	sctp_walk_params(param, hdr, params) {
3796 		__u16 length = ntohs(param.p->length);
3797 
3798 		*errp = param.p;
3799 		if (cnt++ > 2)
3800 			return false;
3801 		switch (param.p->type) {
3802 		case SCTP_PARAM_RESET_OUT_REQUEST:
3803 			if (length < sizeof(struct sctp_strreset_outreq) ||
3804 			    (last && last != SCTP_PARAM_RESET_RESPONSE &&
3805 			     last != SCTP_PARAM_RESET_IN_REQUEST))
3806 				return false;
3807 			break;
3808 		case SCTP_PARAM_RESET_IN_REQUEST:
3809 			if (length < sizeof(struct sctp_strreset_inreq) ||
3810 			    (last && last != SCTP_PARAM_RESET_OUT_REQUEST))
3811 				return false;
3812 			break;
3813 		case SCTP_PARAM_RESET_RESPONSE:
3814 			if ((length != sizeof(struct sctp_strreset_resp) &&
3815 			     length != sizeof(struct sctp_strreset_resptsn)) ||
3816 			    (last && last != SCTP_PARAM_RESET_RESPONSE &&
3817 			     last != SCTP_PARAM_RESET_OUT_REQUEST))
3818 				return false;
3819 			break;
3820 		case SCTP_PARAM_RESET_TSN_REQUEST:
3821 			if (length !=
3822 			    sizeof(struct sctp_strreset_tsnreq) || last)
3823 				return false;
3824 			break;
3825 		case SCTP_PARAM_RESET_ADD_IN_STREAMS:
3826 			if (length != sizeof(struct sctp_strreset_addstrm) ||
3827 			    (last && last != SCTP_PARAM_RESET_ADD_OUT_STREAMS))
3828 				return false;
3829 			break;
3830 		case SCTP_PARAM_RESET_ADD_OUT_STREAMS:
3831 			if (length != sizeof(struct sctp_strreset_addstrm) ||
3832 			    (last && last != SCTP_PARAM_RESET_ADD_IN_STREAMS))
3833 				return false;
3834 			break;
3835 		default:
3836 			return false;
3837 		}
3838 
3839 		last = param.p->type;
3840 	}
3841 
3842 	return true;
3843 }
3844