xref: /openbmc/linux/net/sctp/sm_make_chunk.c (revision 4800cd83)
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, write to
27  * the Free Software Foundation, 59 Temple Place - Suite 330,
28  * Boston, MA 02111-1307, USA.
29  *
30  * Please send any bug reports or fixes you make to the
31  * email address(es):
32  *    lksctp developers <lksctp-developers@lists.sourceforge.net>
33  *
34  * Or submit a bug report through the following website:
35  *    http://www.sf.net/projects/lksctp
36  *
37  * Written or modified by:
38  *    La Monte H.P. Yarroll <piggy@acm.org>
39  *    Karl Knutson          <karl@athena.chicago.il.us>
40  *    C. Robin              <chris@hundredacre.ac.uk>
41  *    Jon Grimm             <jgrimm@us.ibm.com>
42  *    Xingang Guo           <xingang.guo@intel.com>
43  *    Dajiang Zhang	    <dajiang.zhang@nokia.com>
44  *    Sridhar Samudrala	    <sri@us.ibm.com>
45  *    Daisy Chang	    <daisyc@us.ibm.com>
46  *    Ardelle Fan	    <ardelle.fan@intel.com>
47  *    Kevin Gao             <kevin.gao@intel.com>
48  *
49  * Any bugs reported given to us we will try to fix... any fixes shared will
50  * be incorporated into the next SCTP release.
51  */
52 
53 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
54 
55 #include <linux/types.h>
56 #include <linux/kernel.h>
57 #include <linux/ip.h>
58 #include <linux/ipv6.h>
59 #include <linux/net.h>
60 #include <linux/inet.h>
61 #include <linux/scatterlist.h>
62 #include <linux/crypto.h>
63 #include <linux/slab.h>
64 #include <net/sock.h>
65 
66 #include <linux/skbuff.h>
67 #include <linux/random.h>	/* for get_random_bytes */
68 #include <net/sctp/sctp.h>
69 #include <net/sctp/sm.h>
70 
71 SCTP_STATIC
72 struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc,
73 				   __u8 type, __u8 flags, int paylen);
74 static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
75 					const struct sctp_association *asoc,
76 					const struct sctp_chunk *init_chunk,
77 					int *cookie_len,
78 					const __u8 *raw_addrs, int addrs_len);
79 static int sctp_process_param(struct sctp_association *asoc,
80 			      union sctp_params param,
81 			      const union sctp_addr *peer_addr,
82 			      gfp_t gfp);
83 static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
84 			      const void *data);
85 
86 /* What was the inbound interface for this chunk? */
87 int sctp_chunk_iif(const struct sctp_chunk *chunk)
88 {
89 	struct sctp_af *af;
90 	int iif = 0;
91 
92 	af = sctp_get_af_specific(ipver2af(ip_hdr(chunk->skb)->version));
93 	if (af)
94 		iif = af->skb_iif(chunk->skb);
95 
96 	return iif;
97 }
98 
99 /* RFC 2960 3.3.2 Initiation (INIT) (1)
100  *
101  * Note 2: The ECN capable field is reserved for future use of
102  * Explicit Congestion Notification.
103  */
104 static const struct sctp_paramhdr ecap_param = {
105 	SCTP_PARAM_ECN_CAPABLE,
106 	cpu_to_be16(sizeof(struct sctp_paramhdr)),
107 };
108 static const struct sctp_paramhdr prsctp_param = {
109 	SCTP_PARAM_FWD_TSN_SUPPORT,
110 	cpu_to_be16(sizeof(struct sctp_paramhdr)),
111 };
112 
113 /* A helper to initialize an op error inside a
114  * provided chunk, as most cause codes will be embedded inside an
115  * abort chunk.
116  */
117 void  sctp_init_cause(struct sctp_chunk *chunk, __be16 cause_code,
118 		      size_t paylen)
119 {
120 	sctp_errhdr_t err;
121 	__u16 len;
122 
123 	/* Cause code constants are now defined in network order.  */
124 	err.cause = cause_code;
125 	len = sizeof(sctp_errhdr_t) + paylen;
126 	err.length  = htons(len);
127 	chunk->subh.err_hdr = sctp_addto_chunk(chunk, sizeof(sctp_errhdr_t), &err);
128 }
129 
130 /* A helper to initialize an op error inside a
131  * provided chunk, as most cause codes will be embedded inside an
132  * abort chunk.  Differs from sctp_init_cause in that it won't oops
133  * if there isn't enough space in the op error chunk
134  */
135 int sctp_init_cause_fixed(struct sctp_chunk *chunk, __be16 cause_code,
136 		      size_t paylen)
137 {
138 	sctp_errhdr_t err;
139 	__u16 len;
140 
141 	/* Cause code constants are now defined in network order.  */
142 	err.cause = cause_code;
143 	len = sizeof(sctp_errhdr_t) + paylen;
144 	err.length  = htons(len);
145 
146 	if (skb_tailroom(chunk->skb) < len)
147 		return -ENOSPC;
148 	chunk->subh.err_hdr = sctp_addto_chunk_fixed(chunk,
149 						     sizeof(sctp_errhdr_t),
150 						     &err);
151 	return 0;
152 }
153 /* 3.3.2 Initiation (INIT) (1)
154  *
155  * This chunk is used to initiate a SCTP association between two
156  * endpoints. The format of the INIT chunk is shown below:
157  *
158  *     0                   1                   2                   3
159  *     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
160  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
161  *    |   Type = 1    |  Chunk Flags  |      Chunk Length             |
162  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
163  *    |                         Initiate Tag                          |
164  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
165  *    |           Advertised Receiver Window Credit (a_rwnd)          |
166  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
167  *    |  Number of Outbound Streams   |  Number of Inbound Streams    |
168  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
169  *    |                          Initial TSN                          |
170  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
171  *    \                                                               \
172  *    /              Optional/Variable-Length Parameters              /
173  *    \                                                               \
174  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
175  *
176  *
177  * The INIT chunk contains the following parameters. Unless otherwise
178  * noted, each parameter MUST only be included once in the INIT chunk.
179  *
180  * Fixed Parameters                     Status
181  * ----------------------------------------------
182  * Initiate Tag                        Mandatory
183  * Advertised Receiver Window Credit   Mandatory
184  * Number of Outbound Streams          Mandatory
185  * Number of Inbound Streams           Mandatory
186  * Initial TSN                         Mandatory
187  *
188  * Variable Parameters                  Status     Type Value
189  * -------------------------------------------------------------
190  * IPv4 Address (Note 1)               Optional    5
191  * IPv6 Address (Note 1)               Optional    6
192  * Cookie Preservative                 Optional    9
193  * Reserved for ECN Capable (Note 2)   Optional    32768 (0x8000)
194  * Host Name Address (Note 3)          Optional    11
195  * Supported Address Types (Note 4)    Optional    12
196  */
197 struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc,
198 			     const struct sctp_bind_addr *bp,
199 			     gfp_t gfp, int vparam_len)
200 {
201 	sctp_inithdr_t init;
202 	union sctp_params addrs;
203 	size_t chunksize;
204 	struct sctp_chunk *retval = NULL;
205 	int num_types, addrs_len = 0;
206 	struct sctp_sock *sp;
207 	sctp_supported_addrs_param_t sat;
208 	__be16 types[2];
209 	sctp_adaptation_ind_param_t aiparam;
210 	sctp_supported_ext_param_t ext_param;
211 	int num_ext = 0;
212 	__u8 extensions[3];
213 	sctp_paramhdr_t *auth_chunks = NULL,
214 			*auth_hmacs = NULL;
215 
216 	/* RFC 2960 3.3.2 Initiation (INIT) (1)
217 	 *
218 	 * Note 1: The INIT chunks can contain multiple addresses that
219 	 * can be IPv4 and/or IPv6 in any combination.
220 	 */
221 	retval = NULL;
222 
223 	/* Convert the provided bind address list to raw format. */
224 	addrs = sctp_bind_addrs_to_raw(bp, &addrs_len, gfp);
225 
226 	init.init_tag		   = htonl(asoc->c.my_vtag);
227 	init.a_rwnd		   = htonl(asoc->rwnd);
228 	init.num_outbound_streams  = htons(asoc->c.sinit_num_ostreams);
229 	init.num_inbound_streams   = htons(asoc->c.sinit_max_instreams);
230 	init.initial_tsn	   = htonl(asoc->c.initial_tsn);
231 
232 	/* How many address types are needed? */
233 	sp = sctp_sk(asoc->base.sk);
234 	num_types = sp->pf->supported_addrs(sp, types);
235 
236 	chunksize = sizeof(init) + addrs_len;
237 	chunksize += WORD_ROUND(SCTP_SAT_LEN(num_types));
238 	chunksize += sizeof(ecap_param);
239 
240 	if (sctp_prsctp_enable)
241 		chunksize += sizeof(prsctp_param);
242 
243 	/* ADDIP: Section 4.2.7:
244 	 *  An implementation supporting this extension [ADDIP] MUST list
245 	 *  the ASCONF,the ASCONF-ACK, and the AUTH  chunks in its INIT and
246 	 *  INIT-ACK parameters.
247 	 */
248 	if (sctp_addip_enable) {
249 		extensions[num_ext] = SCTP_CID_ASCONF;
250 		extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
251 		num_ext += 2;
252 	}
253 
254 	if (sp->adaptation_ind)
255 		chunksize += sizeof(aiparam);
256 
257 	chunksize += vparam_len;
258 
259 	/* Account for AUTH related parameters */
260 	if (sctp_auth_enable) {
261 		/* Add random parameter length*/
262 		chunksize += sizeof(asoc->c.auth_random);
263 
264 		/* Add HMACS parameter length if any were defined */
265 		auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
266 		if (auth_hmacs->length)
267 			chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
268 		else
269 			auth_hmacs = NULL;
270 
271 		/* Add CHUNKS parameter length */
272 		auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
273 		if (auth_chunks->length)
274 			chunksize += WORD_ROUND(ntohs(auth_chunks->length));
275 		else
276 			auth_chunks = NULL;
277 
278 		extensions[num_ext] = SCTP_CID_AUTH;
279 		num_ext += 1;
280 	}
281 
282 	/* If we have any extensions to report, account for that */
283 	if (num_ext)
284 		chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) +
285 					num_ext);
286 
287 	/* RFC 2960 3.3.2 Initiation (INIT) (1)
288 	 *
289 	 * Note 3: An INIT chunk MUST NOT contain more than one Host
290 	 * Name address parameter. Moreover, the sender of the INIT
291 	 * MUST NOT combine any other address types with the Host Name
292 	 * address in the INIT. The receiver of INIT MUST ignore any
293 	 * other address types if the Host Name address parameter is
294 	 * present in the received INIT chunk.
295 	 *
296 	 * PLEASE DO NOT FIXME [This version does not support Host Name.]
297 	 */
298 
299 	retval = sctp_make_chunk(asoc, SCTP_CID_INIT, 0, chunksize);
300 	if (!retval)
301 		goto nodata;
302 
303 	retval->subh.init_hdr =
304 		sctp_addto_chunk(retval, sizeof(init), &init);
305 	retval->param_hdr.v =
306 		sctp_addto_chunk(retval, addrs_len, addrs.v);
307 
308 	/* RFC 2960 3.3.2 Initiation (INIT) (1)
309 	 *
310 	 * Note 4: This parameter, when present, specifies all the
311 	 * address types the sending endpoint can support. The absence
312 	 * of this parameter indicates that the sending endpoint can
313 	 * support any address type.
314 	 */
315 	sat.param_hdr.type = SCTP_PARAM_SUPPORTED_ADDRESS_TYPES;
316 	sat.param_hdr.length = htons(SCTP_SAT_LEN(num_types));
317 	sctp_addto_chunk(retval, sizeof(sat), &sat);
318 	sctp_addto_chunk(retval, num_types * sizeof(__u16), &types);
319 
320 	sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
321 
322 	/* Add the supported extensions parameter.  Be nice and add this
323 	 * fist before addiding the parameters for the extensions themselves
324 	 */
325 	if (num_ext) {
326 		ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
327 		ext_param.param_hdr.length =
328 			    htons(sizeof(sctp_supported_ext_param_t) + num_ext);
329 		sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
330 				&ext_param);
331 		sctp_addto_param(retval, num_ext, extensions);
332 	}
333 
334 	if (sctp_prsctp_enable)
335 		sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
336 
337 	if (sp->adaptation_ind) {
338 		aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
339 		aiparam.param_hdr.length = htons(sizeof(aiparam));
340 		aiparam.adaptation_ind = htonl(sp->adaptation_ind);
341 		sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
342 	}
343 
344 	/* Add SCTP-AUTH chunks to the parameter list */
345 	if (sctp_auth_enable) {
346 		sctp_addto_chunk(retval, sizeof(asoc->c.auth_random),
347 				 asoc->c.auth_random);
348 		if (auth_hmacs)
349 			sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
350 					auth_hmacs);
351 		if (auth_chunks)
352 			sctp_addto_chunk(retval, ntohs(auth_chunks->length),
353 					auth_chunks);
354 	}
355 nodata:
356 	kfree(addrs.v);
357 	return retval;
358 }
359 
360 struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc,
361 				 const struct sctp_chunk *chunk,
362 				 gfp_t gfp, int unkparam_len)
363 {
364 	sctp_inithdr_t initack;
365 	struct sctp_chunk *retval;
366 	union sctp_params addrs;
367 	struct sctp_sock *sp;
368 	int addrs_len;
369 	sctp_cookie_param_t *cookie;
370 	int cookie_len;
371 	size_t chunksize;
372 	sctp_adaptation_ind_param_t aiparam;
373 	sctp_supported_ext_param_t ext_param;
374 	int num_ext = 0;
375 	__u8 extensions[3];
376 	sctp_paramhdr_t *auth_chunks = NULL,
377 			*auth_hmacs = NULL,
378 			*auth_random = NULL;
379 
380 	retval = NULL;
381 
382 	/* Note: there may be no addresses to embed. */
383 	addrs = sctp_bind_addrs_to_raw(&asoc->base.bind_addr, &addrs_len, gfp);
384 
385 	initack.init_tag	        = htonl(asoc->c.my_vtag);
386 	initack.a_rwnd			= htonl(asoc->rwnd);
387 	initack.num_outbound_streams	= htons(asoc->c.sinit_num_ostreams);
388 	initack.num_inbound_streams	= htons(asoc->c.sinit_max_instreams);
389 	initack.initial_tsn		= htonl(asoc->c.initial_tsn);
390 
391 	/* FIXME:  We really ought to build the cookie right
392 	 * into the packet instead of allocating more fresh memory.
393 	 */
394 	cookie = sctp_pack_cookie(asoc->ep, asoc, chunk, &cookie_len,
395 				  addrs.v, addrs_len);
396 	if (!cookie)
397 		goto nomem_cookie;
398 
399 	/* Calculate the total size of allocation, include the reserved
400 	 * space for reporting unknown parameters if it is specified.
401 	 */
402 	sp = sctp_sk(asoc->base.sk);
403 	chunksize = sizeof(initack) + addrs_len + cookie_len + unkparam_len;
404 
405 	/* Tell peer that we'll do ECN only if peer advertised such cap.  */
406 	if (asoc->peer.ecn_capable)
407 		chunksize += sizeof(ecap_param);
408 
409 	if (asoc->peer.prsctp_capable)
410 		chunksize += sizeof(prsctp_param);
411 
412 	if (asoc->peer.asconf_capable) {
413 		extensions[num_ext] = SCTP_CID_ASCONF;
414 		extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
415 		num_ext += 2;
416 	}
417 
418 	if (sp->adaptation_ind)
419 		chunksize += sizeof(aiparam);
420 
421 	if (asoc->peer.auth_capable) {
422 		auth_random = (sctp_paramhdr_t *)asoc->c.auth_random;
423 		chunksize += ntohs(auth_random->length);
424 
425 		auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
426 		if (auth_hmacs->length)
427 			chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
428 		else
429 			auth_hmacs = NULL;
430 
431 		auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
432 		if (auth_chunks->length)
433 			chunksize += WORD_ROUND(ntohs(auth_chunks->length));
434 		else
435 			auth_chunks = NULL;
436 
437 		extensions[num_ext] = SCTP_CID_AUTH;
438 		num_ext += 1;
439 	}
440 
441 	if (num_ext)
442 		chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) +
443 					num_ext);
444 
445 	/* Now allocate and fill out the chunk.  */
446 	retval = sctp_make_chunk(asoc, SCTP_CID_INIT_ACK, 0, chunksize);
447 	if (!retval)
448 		goto nomem_chunk;
449 
450 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
451 	 *
452 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
453 	 * HEARTBEAT ACK, * etc.) to the same destination transport
454 	 * address from which it received the DATA or control chunk
455 	 * to which it is replying.
456 	 *
457 	 * [INIT ACK back to where the INIT came from.]
458 	 */
459 	retval->transport = chunk->transport;
460 
461 	retval->subh.init_hdr =
462 		sctp_addto_chunk(retval, sizeof(initack), &initack);
463 	retval->param_hdr.v = sctp_addto_chunk(retval, addrs_len, addrs.v);
464 	sctp_addto_chunk(retval, cookie_len, cookie);
465 	if (asoc->peer.ecn_capable)
466 		sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
467 	if (num_ext) {
468 		ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
469 		ext_param.param_hdr.length =
470 			    htons(sizeof(sctp_supported_ext_param_t) + num_ext);
471 		sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
472 				 &ext_param);
473 		sctp_addto_param(retval, num_ext, extensions);
474 	}
475 	if (asoc->peer.prsctp_capable)
476 		sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
477 
478 	if (sp->adaptation_ind) {
479 		aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
480 		aiparam.param_hdr.length = htons(sizeof(aiparam));
481 		aiparam.adaptation_ind = htonl(sp->adaptation_ind);
482 		sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
483 	}
484 
485 	if (asoc->peer.auth_capable) {
486 		sctp_addto_chunk(retval, ntohs(auth_random->length),
487 				 auth_random);
488 		if (auth_hmacs)
489 			sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
490 					auth_hmacs);
491 		if (auth_chunks)
492 			sctp_addto_chunk(retval, ntohs(auth_chunks->length),
493 					auth_chunks);
494 	}
495 
496 	/* We need to remove the const qualifier at this point.  */
497 	retval->asoc = (struct sctp_association *) asoc;
498 
499 nomem_chunk:
500 	kfree(cookie);
501 nomem_cookie:
502 	kfree(addrs.v);
503 	return retval;
504 }
505 
506 /* 3.3.11 Cookie Echo (COOKIE ECHO) (10):
507  *
508  * This chunk is used only during the initialization of an association.
509  * It is sent by the initiator of an association to its peer to complete
510  * the initialization process. This chunk MUST precede any DATA chunk
511  * sent within the association, but MAY be bundled with one or more DATA
512  * chunks in the same packet.
513  *
514  *      0                   1                   2                   3
515  *      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
516  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
517  *     |   Type = 10   |Chunk  Flags   |         Length                |
518  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
519  *     /                     Cookie                                    /
520  *     \                                                               \
521  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
522  *
523  * Chunk Flags: 8 bit
524  *
525  *   Set to zero on transmit and ignored on receipt.
526  *
527  * Length: 16 bits (unsigned integer)
528  *
529  *   Set to the size of the chunk in bytes, including the 4 bytes of
530  *   the chunk header and the size of the Cookie.
531  *
532  * Cookie: variable size
533  *
534  *   This field must contain the exact cookie received in the
535  *   State Cookie parameter from the previous INIT ACK.
536  *
537  *   An implementation SHOULD make the cookie as small as possible
538  *   to insure interoperability.
539  */
540 struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *asoc,
541 				    const struct sctp_chunk *chunk)
542 {
543 	struct sctp_chunk *retval;
544 	void *cookie;
545 	int cookie_len;
546 
547 	cookie = asoc->peer.cookie;
548 	cookie_len = asoc->peer.cookie_len;
549 
550 	/* Build a cookie echo chunk.  */
551 	retval = sctp_make_chunk(asoc, SCTP_CID_COOKIE_ECHO, 0, cookie_len);
552 	if (!retval)
553 		goto nodata;
554 	retval->subh.cookie_hdr =
555 		sctp_addto_chunk(retval, cookie_len, cookie);
556 
557 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
558 	 *
559 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
560 	 * HEARTBEAT ACK, * etc.) to the same destination transport
561 	 * address from which it * received the DATA or control chunk
562 	 * to which it is replying.
563 	 *
564 	 * [COOKIE ECHO back to where the INIT ACK came from.]
565 	 */
566 	if (chunk)
567 		retval->transport = chunk->transport;
568 
569 nodata:
570 	return retval;
571 }
572 
573 /* 3.3.12 Cookie Acknowledgement (COOKIE ACK) (11):
574  *
575  * This chunk is used only during the initialization of an
576  * association.  It is used to acknowledge the receipt of a COOKIE
577  * ECHO chunk.  This chunk MUST precede any DATA or SACK chunk sent
578  * within the association, but MAY be bundled with one or more DATA
579  * chunks or SACK chunk in the same SCTP packet.
580  *
581  *      0                   1                   2                   3
582  *      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
583  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
584  *     |   Type = 11   |Chunk  Flags   |     Length = 4                |
585  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
586  *
587  * Chunk Flags: 8 bits
588  *
589  *   Set to zero on transmit and ignored on receipt.
590  */
591 struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *asoc,
592 				   const struct sctp_chunk *chunk)
593 {
594 	struct sctp_chunk *retval;
595 
596 	retval = sctp_make_chunk(asoc, SCTP_CID_COOKIE_ACK, 0, 0);
597 
598 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
599 	 *
600 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
601 	 * HEARTBEAT ACK, * etc.) to the same destination transport
602 	 * address from which it * received the DATA or control chunk
603 	 * to which it is replying.
604 	 *
605 	 * [COOKIE ACK back to where the COOKIE ECHO came from.]
606 	 */
607 	if (retval && chunk)
608 		retval->transport = chunk->transport;
609 
610 	return retval;
611 }
612 
613 /*
614  *  Appendix A: Explicit Congestion Notification:
615  *  CWR:
616  *
617  *  RFC 2481 details a specific bit for a sender to send in the header of
618  *  its next outbound TCP segment to indicate to its peer that it has
619  *  reduced its congestion window.  This is termed the CWR bit.  For
620  *  SCTP the same indication is made by including the CWR chunk.
621  *  This chunk contains one data element, i.e. the TSN number that
622  *  was sent in the ECNE chunk.  This element represents the lowest
623  *  TSN number in the datagram that was originally marked with the
624  *  CE bit.
625  *
626  *     0                   1                   2                   3
627  *     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
628  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
629  *    | Chunk Type=13 | Flags=00000000|    Chunk Length = 8           |
630  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
631  *    |                      Lowest TSN Number                        |
632  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
633  *
634  *     Note: The CWR is considered a Control chunk.
635  */
636 struct sctp_chunk *sctp_make_cwr(const struct sctp_association *asoc,
637 			    const __u32 lowest_tsn,
638 			    const struct sctp_chunk *chunk)
639 {
640 	struct sctp_chunk *retval;
641 	sctp_cwrhdr_t cwr;
642 
643 	cwr.lowest_tsn = htonl(lowest_tsn);
644 	retval = sctp_make_chunk(asoc, SCTP_CID_ECN_CWR, 0,
645 				 sizeof(sctp_cwrhdr_t));
646 
647 	if (!retval)
648 		goto nodata;
649 
650 	retval->subh.ecn_cwr_hdr =
651 		sctp_addto_chunk(retval, sizeof(cwr), &cwr);
652 
653 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
654 	 *
655 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
656 	 * HEARTBEAT ACK, * etc.) to the same destination transport
657 	 * address from which it * received the DATA or control chunk
658 	 * to which it is replying.
659 	 *
660 	 * [Report a reduced congestion window back to where the ECNE
661 	 * came from.]
662 	 */
663 	if (chunk)
664 		retval->transport = chunk->transport;
665 
666 nodata:
667 	return retval;
668 }
669 
670 /* Make an ECNE chunk.  This is a congestion experienced report.  */
671 struct sctp_chunk *sctp_make_ecne(const struct sctp_association *asoc,
672 			     const __u32 lowest_tsn)
673 {
674 	struct sctp_chunk *retval;
675 	sctp_ecnehdr_t ecne;
676 
677 	ecne.lowest_tsn = htonl(lowest_tsn);
678 	retval = sctp_make_chunk(asoc, SCTP_CID_ECN_ECNE, 0,
679 				 sizeof(sctp_ecnehdr_t));
680 	if (!retval)
681 		goto nodata;
682 	retval->subh.ecne_hdr =
683 		sctp_addto_chunk(retval, sizeof(ecne), &ecne);
684 
685 nodata:
686 	return retval;
687 }
688 
689 /* Make a DATA chunk for the given association from the provided
690  * parameters.  However, do not populate the data payload.
691  */
692 struct sctp_chunk *sctp_make_datafrag_empty(struct sctp_association *asoc,
693 				       const struct sctp_sndrcvinfo *sinfo,
694 				       int data_len, __u8 flags, __u16 ssn)
695 {
696 	struct sctp_chunk *retval;
697 	struct sctp_datahdr dp;
698 	int chunk_len;
699 
700 	/* We assign the TSN as LATE as possible, not here when
701 	 * creating the chunk.
702 	 */
703 	dp.tsn = 0;
704 	dp.stream = htons(sinfo->sinfo_stream);
705 	dp.ppid   = sinfo->sinfo_ppid;
706 
707 	/* Set the flags for an unordered send.  */
708 	if (sinfo->sinfo_flags & SCTP_UNORDERED) {
709 		flags |= SCTP_DATA_UNORDERED;
710 		dp.ssn = 0;
711 	} else
712 		dp.ssn = htons(ssn);
713 
714 	chunk_len = sizeof(dp) + data_len;
715 	retval = sctp_make_chunk(asoc, SCTP_CID_DATA, flags, chunk_len);
716 	if (!retval)
717 		goto nodata;
718 
719 	retval->subh.data_hdr = sctp_addto_chunk(retval, sizeof(dp), &dp);
720 	memcpy(&retval->sinfo, sinfo, sizeof(struct sctp_sndrcvinfo));
721 
722 nodata:
723 	return retval;
724 }
725 
726 /* Create a selective ackowledgement (SACK) for the given
727  * association.  This reports on which TSN's we've seen to date,
728  * including duplicates and gaps.
729  */
730 struct sctp_chunk *sctp_make_sack(const struct sctp_association *asoc)
731 {
732 	struct sctp_chunk *retval;
733 	struct sctp_sackhdr sack;
734 	int len;
735 	__u32 ctsn;
736 	__u16 num_gabs, num_dup_tsns;
737 	struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
738 	struct sctp_gap_ack_block gabs[SCTP_MAX_GABS];
739 
740 	memset(gabs, 0, sizeof(gabs));
741 	ctsn = sctp_tsnmap_get_ctsn(map);
742 	SCTP_DEBUG_PRINTK("sackCTSNAck sent:  0x%x.\n", ctsn);
743 
744 	/* How much room is needed in the chunk? */
745 	num_gabs = sctp_tsnmap_num_gabs(map, gabs);
746 	num_dup_tsns = sctp_tsnmap_num_dups(map);
747 
748 	/* Initialize the SACK header.  */
749 	sack.cum_tsn_ack	    = htonl(ctsn);
750 	sack.a_rwnd 		    = htonl(asoc->a_rwnd);
751 	sack.num_gap_ack_blocks     = htons(num_gabs);
752 	sack.num_dup_tsns           = htons(num_dup_tsns);
753 
754 	len = sizeof(sack)
755 		+ sizeof(struct sctp_gap_ack_block) * num_gabs
756 		+ sizeof(__u32) * num_dup_tsns;
757 
758 	/* Create the chunk.  */
759 	retval = sctp_make_chunk(asoc, SCTP_CID_SACK, 0, len);
760 	if (!retval)
761 		goto nodata;
762 
763 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
764 	 *
765 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
766 	 * HEARTBEAT ACK, etc.) to the same destination transport
767 	 * address from which it received the DATA or control chunk to
768 	 * which it is replying.  This rule should also be followed if
769 	 * the endpoint is bundling DATA chunks together with the
770 	 * reply chunk.
771 	 *
772 	 * However, when acknowledging multiple DATA chunks received
773 	 * in packets from different source addresses in a single
774 	 * SACK, the SACK chunk may be transmitted to one of the
775 	 * destination transport addresses from which the DATA or
776 	 * control chunks being acknowledged were received.
777 	 *
778 	 * [BUG:  We do not implement the following paragraph.
779 	 * Perhaps we should remember the last transport we used for a
780 	 * SACK and avoid that (if possible) if we have seen any
781 	 * duplicates. --piggy]
782 	 *
783 	 * When a receiver of a duplicate DATA chunk sends a SACK to a
784 	 * multi- homed endpoint it MAY be beneficial to vary the
785 	 * destination address and not use the source address of the
786 	 * DATA chunk.  The reason being that receiving a duplicate
787 	 * from a multi-homed endpoint might indicate that the return
788 	 * path (as specified in the source address of the DATA chunk)
789 	 * for the SACK is broken.
790 	 *
791 	 * [Send to the address from which we last received a DATA chunk.]
792 	 */
793 	retval->transport = asoc->peer.last_data_from;
794 
795 	retval->subh.sack_hdr =
796 		sctp_addto_chunk(retval, sizeof(sack), &sack);
797 
798 	/* Add the gap ack block information.   */
799 	if (num_gabs)
800 		sctp_addto_chunk(retval, sizeof(__u32) * num_gabs,
801 				 gabs);
802 
803 	/* Add the duplicate TSN information.  */
804 	if (num_dup_tsns)
805 		sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns,
806 				 sctp_tsnmap_get_dups(map));
807 
808 nodata:
809 	return retval;
810 }
811 
812 /* Make a SHUTDOWN chunk. */
813 struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
814 				      const struct sctp_chunk *chunk)
815 {
816 	struct sctp_chunk *retval;
817 	sctp_shutdownhdr_t shut;
818 	__u32 ctsn;
819 
820 	ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
821 	shut.cum_tsn_ack = htonl(ctsn);
822 
823 	retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN, 0,
824 				 sizeof(sctp_shutdownhdr_t));
825 	if (!retval)
826 		goto nodata;
827 
828 	retval->subh.shutdown_hdr =
829 		sctp_addto_chunk(retval, sizeof(shut), &shut);
830 
831 	if (chunk)
832 		retval->transport = chunk->transport;
833 nodata:
834 	return retval;
835 }
836 
837 struct sctp_chunk *sctp_make_shutdown_ack(const struct sctp_association *asoc,
838 				     const struct sctp_chunk *chunk)
839 {
840 	struct sctp_chunk *retval;
841 
842 	retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN_ACK, 0, 0);
843 
844 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
845 	 *
846 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
847 	 * HEARTBEAT ACK, * etc.) to the same destination transport
848 	 * address from which it * received the DATA or control chunk
849 	 * to which it is replying.
850 	 *
851 	 * [ACK back to where the SHUTDOWN came from.]
852 	 */
853 	if (retval && chunk)
854 		retval->transport = chunk->transport;
855 
856 	return retval;
857 }
858 
859 struct sctp_chunk *sctp_make_shutdown_complete(
860 	const struct sctp_association *asoc,
861 	const struct sctp_chunk *chunk)
862 {
863 	struct sctp_chunk *retval;
864 	__u8 flags = 0;
865 
866 	/* Set the T-bit if we have no association (vtag will be
867 	 * reflected)
868 	 */
869 	flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;
870 
871 	retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags, 0);
872 
873 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
874 	 *
875 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
876 	 * HEARTBEAT ACK, * etc.) to the same destination transport
877 	 * address from which it * received the DATA or control chunk
878 	 * to which it is replying.
879 	 *
880 	 * [Report SHUTDOWN COMPLETE back to where the SHUTDOWN ACK
881 	 * came from.]
882 	 */
883 	if (retval && chunk)
884 		retval->transport = chunk->transport;
885 
886 	return retval;
887 }
888 
889 /* Create an ABORT.  Note that we set the T bit if we have no
890  * association, except when responding to an INIT (sctpimpguide 2.41).
891  */
892 struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc,
893 			      const struct sctp_chunk *chunk,
894 			      const size_t hint)
895 {
896 	struct sctp_chunk *retval;
897 	__u8 flags = 0;
898 
899 	/* Set the T-bit if we have no association and 'chunk' is not
900 	 * an INIT (vtag will be reflected).
901 	 */
902 	if (!asoc) {
903 		if (chunk && chunk->chunk_hdr &&
904 		    chunk->chunk_hdr->type == SCTP_CID_INIT)
905 			flags = 0;
906 		else
907 			flags = SCTP_CHUNK_FLAG_T;
908 	}
909 
910 	retval = sctp_make_chunk(asoc, SCTP_CID_ABORT, flags, hint);
911 
912 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
913 	 *
914 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
915 	 * HEARTBEAT ACK, * etc.) to the same destination transport
916 	 * address from which it * received the DATA or control chunk
917 	 * to which it is replying.
918 	 *
919 	 * [ABORT back to where the offender came from.]
920 	 */
921 	if (retval && chunk)
922 		retval->transport = chunk->transport;
923 
924 	return retval;
925 }
926 
927 /* Helper to create ABORT with a NO_USER_DATA error.  */
928 struct sctp_chunk *sctp_make_abort_no_data(
929 	const struct sctp_association *asoc,
930 	const struct sctp_chunk *chunk, __u32 tsn)
931 {
932 	struct sctp_chunk *retval;
933 	__be32 payload;
934 
935 	retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t)
936 				 + sizeof(tsn));
937 
938 	if (!retval)
939 		goto no_mem;
940 
941 	/* Put the tsn back into network byte order.  */
942 	payload = htonl(tsn);
943 	sctp_init_cause(retval, SCTP_ERROR_NO_DATA, sizeof(payload));
944 	sctp_addto_chunk(retval, sizeof(payload), (const void *)&payload);
945 
946 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
947 	 *
948 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
949 	 * HEARTBEAT ACK, * etc.) to the same destination transport
950 	 * address from which it * received the DATA or control chunk
951 	 * to which it is replying.
952 	 *
953 	 * [ABORT back to where the offender came from.]
954 	 */
955 	if (chunk)
956 		retval->transport = chunk->transport;
957 
958 no_mem:
959 	return retval;
960 }
961 
962 /* Helper to create ABORT with a SCTP_ERROR_USER_ABORT error.  */
963 struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *asoc,
964 					const struct msghdr *msg,
965 					size_t paylen)
966 {
967 	struct sctp_chunk *retval;
968 	void *payload = NULL;
969 	int err;
970 
971 	retval = sctp_make_abort(asoc, NULL, sizeof(sctp_errhdr_t) + paylen);
972 	if (!retval)
973 		goto err_chunk;
974 
975 	if (paylen) {
976 		/* Put the msg_iov together into payload.  */
977 		payload = kmalloc(paylen, GFP_KERNEL);
978 		if (!payload)
979 			goto err_payload;
980 
981 		err = memcpy_fromiovec(payload, msg->msg_iov, paylen);
982 		if (err < 0)
983 			goto err_copy;
984 	}
985 
986 	sctp_init_cause(retval, SCTP_ERROR_USER_ABORT, paylen);
987 	sctp_addto_chunk(retval, paylen, payload);
988 
989 	if (paylen)
990 		kfree(payload);
991 
992 	return retval;
993 
994 err_copy:
995 	kfree(payload);
996 err_payload:
997 	sctp_chunk_free(retval);
998 	retval = NULL;
999 err_chunk:
1000 	return retval;
1001 }
1002 
1003 /* Append bytes to the end of a parameter.  Will panic if chunk is not big
1004  * enough.
1005  */
1006 static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
1007 			      const void *data)
1008 {
1009 	void *target;
1010 	int chunklen = ntohs(chunk->chunk_hdr->length);
1011 
1012 	target = skb_put(chunk->skb, len);
1013 
1014 	if (data)
1015 		memcpy(target, data, len);
1016 	else
1017 		memset(target, 0, len);
1018 
1019 	/* Adjust the chunk length field.  */
1020 	chunk->chunk_hdr->length = htons(chunklen + len);
1021 	chunk->chunk_end = skb_tail_pointer(chunk->skb);
1022 
1023 	return target;
1024 }
1025 
1026 /* Make an ABORT chunk with a PROTOCOL VIOLATION cause code. */
1027 struct sctp_chunk *sctp_make_abort_violation(
1028 	const struct sctp_association *asoc,
1029 	const struct sctp_chunk *chunk,
1030 	const __u8   *payload,
1031 	const size_t paylen)
1032 {
1033 	struct sctp_chunk  *retval;
1034 	struct sctp_paramhdr phdr;
1035 
1036 	retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t) + paylen
1037 					+ sizeof(sctp_paramhdr_t));
1038 	if (!retval)
1039 		goto end;
1040 
1041 	sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, paylen
1042 					+ sizeof(sctp_paramhdr_t));
1043 
1044 	phdr.type = htons(chunk->chunk_hdr->type);
1045 	phdr.length = chunk->chunk_hdr->length;
1046 	sctp_addto_chunk(retval, paylen, payload);
1047 	sctp_addto_param(retval, sizeof(sctp_paramhdr_t), &phdr);
1048 
1049 end:
1050 	return retval;
1051 }
1052 
1053 struct sctp_chunk *sctp_make_violation_paramlen(
1054 	const struct sctp_association *asoc,
1055 	const struct sctp_chunk *chunk,
1056 	struct sctp_paramhdr *param)
1057 {
1058 	struct sctp_chunk *retval;
1059 	static const char error[] = "The following parameter had invalid length:";
1060 	size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t) +
1061 				sizeof(sctp_paramhdr_t);
1062 
1063 	retval = sctp_make_abort(asoc, chunk, payload_len);
1064 	if (!retval)
1065 		goto nodata;
1066 
1067 	sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION,
1068 			sizeof(error) + sizeof(sctp_paramhdr_t));
1069 	sctp_addto_chunk(retval, sizeof(error), error);
1070 	sctp_addto_param(retval, sizeof(sctp_paramhdr_t), param);
1071 
1072 nodata:
1073 	return retval;
1074 }
1075 
1076 /* Make a HEARTBEAT chunk.  */
1077 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
1078 				  const struct sctp_transport *transport,
1079 				  const void *payload, const size_t paylen)
1080 {
1081 	struct sctp_chunk *retval = sctp_make_chunk(asoc, SCTP_CID_HEARTBEAT,
1082 						    0, paylen);
1083 
1084 	if (!retval)
1085 		goto nodata;
1086 
1087 	/* Cast away the 'const', as this is just telling the chunk
1088 	 * what transport it belongs to.
1089 	 */
1090 	retval->transport = (struct sctp_transport *) transport;
1091 	retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);
1092 
1093 nodata:
1094 	return retval;
1095 }
1096 
1097 struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc,
1098 				      const struct sctp_chunk *chunk,
1099 				      const void *payload, const size_t paylen)
1100 {
1101 	struct sctp_chunk *retval;
1102 
1103 	retval  = sctp_make_chunk(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen);
1104 	if (!retval)
1105 		goto nodata;
1106 
1107 	retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);
1108 
1109 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
1110 	 *
1111 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1112 	 * HEARTBEAT ACK, * etc.) to the same destination transport
1113 	 * address from which it * received the DATA or control chunk
1114 	 * to which it is replying.
1115 	 *
1116 	 * [HBACK back to where the HEARTBEAT came from.]
1117 	 */
1118 	if (chunk)
1119 		retval->transport = chunk->transport;
1120 
1121 nodata:
1122 	return retval;
1123 }
1124 
1125 /* Create an Operation Error chunk with the specified space reserved.
1126  * This routine can be used for containing multiple causes in the chunk.
1127  */
1128 static struct sctp_chunk *sctp_make_op_error_space(
1129 	const struct sctp_association *asoc,
1130 	const struct sctp_chunk *chunk,
1131 	size_t size)
1132 {
1133 	struct sctp_chunk *retval;
1134 
1135 	retval = sctp_make_chunk(asoc, SCTP_CID_ERROR, 0,
1136 				 sizeof(sctp_errhdr_t) + size);
1137 	if (!retval)
1138 		goto nodata;
1139 
1140 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
1141 	 *
1142 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1143 	 * HEARTBEAT ACK, etc.) to the same destination transport
1144 	 * address from which it received the DATA or control chunk
1145 	 * to which it is replying.
1146 	 *
1147 	 */
1148 	if (chunk)
1149 		retval->transport = chunk->transport;
1150 
1151 nodata:
1152 	return retval;
1153 }
1154 
1155 /* Create an Operation Error chunk of a fixed size,
1156  * specifically, max(asoc->pathmtu, SCTP_DEFAULT_MAXSEGMENT)
1157  * This is a helper function to allocate an error chunk for
1158  * for those invalid parameter codes in which we may not want
1159  * to report all the errors, if the incomming chunk is large
1160  */
1161 static inline struct sctp_chunk *sctp_make_op_error_fixed(
1162 	const struct sctp_association *asoc,
1163 	const struct sctp_chunk *chunk)
1164 {
1165 	size_t size = asoc ? asoc->pathmtu : 0;
1166 
1167 	if (!size)
1168 		size = SCTP_DEFAULT_MAXSEGMENT;
1169 
1170 	return sctp_make_op_error_space(asoc, chunk, size);
1171 }
1172 
1173 /* Create an Operation Error chunk.  */
1174 struct sctp_chunk *sctp_make_op_error(const struct sctp_association *asoc,
1175 				 const struct sctp_chunk *chunk,
1176 				 __be16 cause_code, const void *payload,
1177 				 size_t paylen, size_t reserve_tail)
1178 {
1179 	struct sctp_chunk *retval;
1180 
1181 	retval = sctp_make_op_error_space(asoc, chunk, paylen + reserve_tail);
1182 	if (!retval)
1183 		goto nodata;
1184 
1185 	sctp_init_cause(retval, cause_code, paylen + reserve_tail);
1186 	sctp_addto_chunk(retval, paylen, payload);
1187 	if (reserve_tail)
1188 		sctp_addto_param(retval, reserve_tail, NULL);
1189 
1190 nodata:
1191 	return retval;
1192 }
1193 
1194 struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc)
1195 {
1196 	struct sctp_chunk *retval;
1197 	struct sctp_hmac *hmac_desc;
1198 	struct sctp_authhdr auth_hdr;
1199 	__u8 *hmac;
1200 
1201 	/* Get the first hmac that the peer told us to use */
1202 	hmac_desc = sctp_auth_asoc_get_hmac(asoc);
1203 	if (unlikely(!hmac_desc))
1204 		return NULL;
1205 
1206 	retval = sctp_make_chunk(asoc, SCTP_CID_AUTH, 0,
1207 			hmac_desc->hmac_len + sizeof(sctp_authhdr_t));
1208 	if (!retval)
1209 		return NULL;
1210 
1211 	auth_hdr.hmac_id = htons(hmac_desc->hmac_id);
1212 	auth_hdr.shkey_id = htons(asoc->active_key_id);
1213 
1214 	retval->subh.auth_hdr = sctp_addto_chunk(retval, sizeof(sctp_authhdr_t),
1215 						&auth_hdr);
1216 
1217 	hmac = skb_put(retval->skb, hmac_desc->hmac_len);
1218 	memset(hmac, 0, hmac_desc->hmac_len);
1219 
1220 	/* Adjust the chunk header to include the empty MAC */
1221 	retval->chunk_hdr->length =
1222 		htons(ntohs(retval->chunk_hdr->length) + hmac_desc->hmac_len);
1223 	retval->chunk_end = skb_tail_pointer(retval->skb);
1224 
1225 	return retval;
1226 }
1227 
1228 
1229 /********************************************************************
1230  * 2nd Level Abstractions
1231  ********************************************************************/
1232 
1233 /* Turn an skb into a chunk.
1234  * FIXME: Eventually move the structure directly inside the skb->cb[].
1235  */
1236 struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
1237 			    const struct sctp_association *asoc,
1238 			    struct sock *sk)
1239 {
1240 	struct sctp_chunk *retval;
1241 
1242 	retval = kmem_cache_zalloc(sctp_chunk_cachep, GFP_ATOMIC);
1243 
1244 	if (!retval)
1245 		goto nodata;
1246 
1247 	if (!sk) {
1248 		SCTP_DEBUG_PRINTK("chunkifying skb %p w/o an sk\n", skb);
1249 	}
1250 
1251 	INIT_LIST_HEAD(&retval->list);
1252 	retval->skb		= skb;
1253 	retval->asoc		= (struct sctp_association *)asoc;
1254 	retval->has_tsn		= 0;
1255 	retval->has_ssn         = 0;
1256 	retval->rtt_in_progress	= 0;
1257 	retval->sent_at		= 0;
1258 	retval->singleton	= 1;
1259 	retval->end_of_packet	= 0;
1260 	retval->ecn_ce_done	= 0;
1261 	retval->pdiscard	= 0;
1262 
1263 	/* sctpimpguide-05.txt Section 2.8.2
1264 	 * M1) Each time a new DATA chunk is transmitted
1265 	 * set the 'TSN.Missing.Report' count for that TSN to 0. The
1266 	 * 'TSN.Missing.Report' count will be used to determine missing chunks
1267 	 * and when to fast retransmit.
1268 	 */
1269 	retval->tsn_missing_report = 0;
1270 	retval->tsn_gap_acked = 0;
1271 	retval->fast_retransmit = SCTP_CAN_FRTX;
1272 
1273 	/* If this is a fragmented message, track all fragments
1274 	 * of the message (for SEND_FAILED).
1275 	 */
1276 	retval->msg = NULL;
1277 
1278 	/* Polish the bead hole.  */
1279 	INIT_LIST_HEAD(&retval->transmitted_list);
1280 	INIT_LIST_HEAD(&retval->frag_list);
1281 	SCTP_DBG_OBJCNT_INC(chunk);
1282 	atomic_set(&retval->refcnt, 1);
1283 
1284 nodata:
1285 	return retval;
1286 }
1287 
1288 /* Set chunk->source and dest based on the IP header in chunk->skb.  */
1289 void sctp_init_addrs(struct sctp_chunk *chunk, union sctp_addr *src,
1290 		     union sctp_addr *dest)
1291 {
1292 	memcpy(&chunk->source, src, sizeof(union sctp_addr));
1293 	memcpy(&chunk->dest, dest, sizeof(union sctp_addr));
1294 }
1295 
1296 /* Extract the source address from a chunk.  */
1297 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk)
1298 {
1299 	/* If we have a known transport, use that.  */
1300 	if (chunk->transport) {
1301 		return &chunk->transport->ipaddr;
1302 	} else {
1303 		/* Otherwise, extract it from the IP header.  */
1304 		return &chunk->source;
1305 	}
1306 }
1307 
1308 /* Create a new chunk, setting the type and flags headers from the
1309  * arguments, reserving enough space for a 'paylen' byte payload.
1310  */
1311 SCTP_STATIC
1312 struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc,
1313 				   __u8 type, __u8 flags, int paylen)
1314 {
1315 	struct sctp_chunk *retval;
1316 	sctp_chunkhdr_t *chunk_hdr;
1317 	struct sk_buff *skb;
1318 	struct sock *sk;
1319 
1320 	/* No need to allocate LL here, as this is only a chunk. */
1321 	skb = alloc_skb(WORD_ROUND(sizeof(sctp_chunkhdr_t) + paylen),
1322 			GFP_ATOMIC);
1323 	if (!skb)
1324 		goto nodata;
1325 
1326 	/* Make room for the chunk header.  */
1327 	chunk_hdr = (sctp_chunkhdr_t *)skb_put(skb, sizeof(sctp_chunkhdr_t));
1328 	chunk_hdr->type	  = type;
1329 	chunk_hdr->flags  = flags;
1330 	chunk_hdr->length = htons(sizeof(sctp_chunkhdr_t));
1331 
1332 	sk = asoc ? asoc->base.sk : NULL;
1333 	retval = sctp_chunkify(skb, asoc, sk);
1334 	if (!retval) {
1335 		kfree_skb(skb);
1336 		goto nodata;
1337 	}
1338 
1339 	retval->chunk_hdr = chunk_hdr;
1340 	retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(struct sctp_chunkhdr);
1341 
1342 	/* Determine if the chunk needs to be authenticated */
1343 	if (sctp_auth_send_cid(type, asoc))
1344 		retval->auth = 1;
1345 
1346 	/* Set the skb to the belonging sock for accounting.  */
1347 	skb->sk = sk;
1348 
1349 	return retval;
1350 nodata:
1351 	return NULL;
1352 }
1353 
1354 
1355 /* Release the memory occupied by a chunk.  */
1356 static void sctp_chunk_destroy(struct sctp_chunk *chunk)
1357 {
1358 	BUG_ON(!list_empty(&chunk->list));
1359 	list_del_init(&chunk->transmitted_list);
1360 
1361 	/* Free the chunk skb data and the SCTP_chunk stub itself. */
1362 	dev_kfree_skb(chunk->skb);
1363 
1364 	SCTP_DBG_OBJCNT_DEC(chunk);
1365 	kmem_cache_free(sctp_chunk_cachep, chunk);
1366 }
1367 
1368 /* Possibly, free the chunk.  */
1369 void sctp_chunk_free(struct sctp_chunk *chunk)
1370 {
1371 	/* Release our reference on the message tracker. */
1372 	if (chunk->msg)
1373 		sctp_datamsg_put(chunk->msg);
1374 
1375 	sctp_chunk_put(chunk);
1376 }
1377 
1378 /* Grab a reference to the chunk. */
1379 void sctp_chunk_hold(struct sctp_chunk *ch)
1380 {
1381 	atomic_inc(&ch->refcnt);
1382 }
1383 
1384 /* Release a reference to the chunk. */
1385 void sctp_chunk_put(struct sctp_chunk *ch)
1386 {
1387 	if (atomic_dec_and_test(&ch->refcnt))
1388 		sctp_chunk_destroy(ch);
1389 }
1390 
1391 /* Append bytes to the end of a chunk.  Will panic if chunk is not big
1392  * enough.
1393  */
1394 void *sctp_addto_chunk(struct sctp_chunk *chunk, int len, const void *data)
1395 {
1396 	void *target;
1397 	void *padding;
1398 	int chunklen = ntohs(chunk->chunk_hdr->length);
1399 	int padlen = WORD_ROUND(chunklen) - chunklen;
1400 
1401 	padding = skb_put(chunk->skb, padlen);
1402 	target = skb_put(chunk->skb, len);
1403 
1404 	memset(padding, 0, padlen);
1405 	memcpy(target, data, len);
1406 
1407 	/* Adjust the chunk length field.  */
1408 	chunk->chunk_hdr->length = htons(chunklen + padlen + len);
1409 	chunk->chunk_end = skb_tail_pointer(chunk->skb);
1410 
1411 	return target;
1412 }
1413 
1414 /* Append bytes to the end of a chunk. Returns NULL if there isn't sufficient
1415  * space in the chunk
1416  */
1417 void *sctp_addto_chunk_fixed(struct sctp_chunk *chunk,
1418 			     int len, const void *data)
1419 {
1420 	if (skb_tailroom(chunk->skb) >= len)
1421 		return sctp_addto_chunk(chunk, len, data);
1422 	else
1423 		return NULL;
1424 }
1425 
1426 /* Append bytes from user space to the end of a chunk.  Will panic if
1427  * chunk is not big enough.
1428  * Returns a kernel err value.
1429  */
1430 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int off, int len,
1431 			  struct iovec *data)
1432 {
1433 	__u8 *target;
1434 	int err = 0;
1435 
1436 	/* Make room in chunk for data.  */
1437 	target = skb_put(chunk->skb, len);
1438 
1439 	/* Copy data (whole iovec) into chunk */
1440 	if ((err = memcpy_fromiovecend(target, data, off, len)))
1441 		goto out;
1442 
1443 	/* Adjust the chunk length field.  */
1444 	chunk->chunk_hdr->length =
1445 		htons(ntohs(chunk->chunk_hdr->length) + len);
1446 	chunk->chunk_end = skb_tail_pointer(chunk->skb);
1447 
1448 out:
1449 	return err;
1450 }
1451 
1452 /* Helper function to assign a TSN if needed.  This assumes that both
1453  * the data_hdr and association have already been assigned.
1454  */
1455 void sctp_chunk_assign_ssn(struct sctp_chunk *chunk)
1456 {
1457 	struct sctp_datamsg *msg;
1458 	struct sctp_chunk *lchunk;
1459 	struct sctp_stream *stream;
1460 	__u16 ssn;
1461 	__u16 sid;
1462 
1463 	if (chunk->has_ssn)
1464 		return;
1465 
1466 	/* All fragments will be on the same stream */
1467 	sid = ntohs(chunk->subh.data_hdr->stream);
1468 	stream = &chunk->asoc->ssnmap->out;
1469 
1470 	/* Now assign the sequence number to the entire message.
1471 	 * All fragments must have the same stream sequence number.
1472 	 */
1473 	msg = chunk->msg;
1474 	list_for_each_entry(lchunk, &msg->chunks, frag_list) {
1475 		if (lchunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
1476 			ssn = 0;
1477 		} else {
1478 			if (lchunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG)
1479 				ssn = sctp_ssn_next(stream, sid);
1480 			else
1481 				ssn = sctp_ssn_peek(stream, sid);
1482 		}
1483 
1484 		lchunk->subh.data_hdr->ssn = htons(ssn);
1485 		lchunk->has_ssn = 1;
1486 	}
1487 }
1488 
1489 /* Helper function to assign a TSN if needed.  This assumes that both
1490  * the data_hdr and association have already been assigned.
1491  */
1492 void sctp_chunk_assign_tsn(struct sctp_chunk *chunk)
1493 {
1494 	if (!chunk->has_tsn) {
1495 		/* This is the last possible instant to
1496 		 * assign a TSN.
1497 		 */
1498 		chunk->subh.data_hdr->tsn =
1499 			htonl(sctp_association_get_next_tsn(chunk->asoc));
1500 		chunk->has_tsn = 1;
1501 	}
1502 }
1503 
1504 /* Create a CLOSED association to use with an incoming packet.  */
1505 struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *ep,
1506 					struct sctp_chunk *chunk,
1507 					gfp_t gfp)
1508 {
1509 	struct sctp_association *asoc;
1510 	struct sk_buff *skb;
1511 	sctp_scope_t scope;
1512 	struct sctp_af *af;
1513 
1514 	/* Create the bare association.  */
1515 	scope = sctp_scope(sctp_source(chunk));
1516 	asoc = sctp_association_new(ep, ep->base.sk, scope, gfp);
1517 	if (!asoc)
1518 		goto nodata;
1519 	asoc->temp = 1;
1520 	skb = chunk->skb;
1521 	/* Create an entry for the source address of the packet.  */
1522 	af = sctp_get_af_specific(ipver2af(ip_hdr(skb)->version));
1523 	if (unlikely(!af))
1524 		goto fail;
1525 	af->from_skb(&asoc->c.peer_addr, skb, 1);
1526 nodata:
1527 	return asoc;
1528 
1529 fail:
1530 	sctp_association_free(asoc);
1531 	return NULL;
1532 }
1533 
1534 /* Build a cookie representing asoc.
1535  * This INCLUDES the param header needed to put the cookie in the INIT ACK.
1536  */
1537 static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
1538 				      const struct sctp_association *asoc,
1539 				      const struct sctp_chunk *init_chunk,
1540 				      int *cookie_len,
1541 				      const __u8 *raw_addrs, int addrs_len)
1542 {
1543 	sctp_cookie_param_t *retval;
1544 	struct sctp_signed_cookie *cookie;
1545 	struct scatterlist sg;
1546 	int headersize, bodysize;
1547 	unsigned int keylen;
1548 	char *key;
1549 
1550 	/* Header size is static data prior to the actual cookie, including
1551 	 * any padding.
1552 	 */
1553 	headersize = sizeof(sctp_paramhdr_t) +
1554 		     (sizeof(struct sctp_signed_cookie) -
1555 		      sizeof(struct sctp_cookie));
1556 	bodysize = sizeof(struct sctp_cookie)
1557 		+ ntohs(init_chunk->chunk_hdr->length) + addrs_len;
1558 
1559 	/* Pad out the cookie to a multiple to make the signature
1560 	 * functions simpler to write.
1561 	 */
1562 	if (bodysize % SCTP_COOKIE_MULTIPLE)
1563 		bodysize += SCTP_COOKIE_MULTIPLE
1564 			- (bodysize % SCTP_COOKIE_MULTIPLE);
1565 	*cookie_len = headersize + bodysize;
1566 
1567 	/* Clear this memory since we are sending this data structure
1568 	 * out on the network.
1569 	 */
1570 	retval = kzalloc(*cookie_len, GFP_ATOMIC);
1571 	if (!retval)
1572 		goto nodata;
1573 
1574 	cookie = (struct sctp_signed_cookie *) retval->body;
1575 
1576 	/* Set up the parameter header.  */
1577 	retval->p.type = SCTP_PARAM_STATE_COOKIE;
1578 	retval->p.length = htons(*cookie_len);
1579 
1580 	/* Copy the cookie part of the association itself.  */
1581 	cookie->c = asoc->c;
1582 	/* Save the raw address list length in the cookie. */
1583 	cookie->c.raw_addr_list_len = addrs_len;
1584 
1585 	/* Remember PR-SCTP capability. */
1586 	cookie->c.prsctp_capable = asoc->peer.prsctp_capable;
1587 
1588 	/* Save adaptation indication in the cookie. */
1589 	cookie->c.adaptation_ind = asoc->peer.adaptation_ind;
1590 
1591 	/* Set an expiration time for the cookie.  */
1592 	do_gettimeofday(&cookie->c.expiration);
1593 	TIMEVAL_ADD(asoc->cookie_life, cookie->c.expiration);
1594 
1595 	/* Copy the peer's init packet.  */
1596 	memcpy(&cookie->c.peer_init[0], init_chunk->chunk_hdr,
1597 	       ntohs(init_chunk->chunk_hdr->length));
1598 
1599 	/* Copy the raw local address list of the association. */
1600 	memcpy((__u8 *)&cookie->c.peer_init[0] +
1601 	       ntohs(init_chunk->chunk_hdr->length), raw_addrs, addrs_len);
1602 
1603 	if (sctp_sk(ep->base.sk)->hmac) {
1604 		struct hash_desc desc;
1605 
1606 		/* Sign the message.  */
1607 		sg_init_one(&sg, &cookie->c, bodysize);
1608 		keylen = SCTP_SECRET_SIZE;
1609 		key = (char *)ep->secret_key[ep->current_key];
1610 		desc.tfm = sctp_sk(ep->base.sk)->hmac;
1611 		desc.flags = 0;
1612 
1613 		if (crypto_hash_setkey(desc.tfm, key, keylen) ||
1614 		    crypto_hash_digest(&desc, &sg, bodysize, cookie->signature))
1615 			goto free_cookie;
1616 	}
1617 
1618 	return retval;
1619 
1620 free_cookie:
1621 	kfree(retval);
1622 nodata:
1623 	*cookie_len = 0;
1624 	return NULL;
1625 }
1626 
1627 /* Unpack the cookie from COOKIE ECHO chunk, recreating the association.  */
1628 struct sctp_association *sctp_unpack_cookie(
1629 	const struct sctp_endpoint *ep,
1630 	const struct sctp_association *asoc,
1631 	struct sctp_chunk *chunk, gfp_t gfp,
1632 	int *error, struct sctp_chunk **errp)
1633 {
1634 	struct sctp_association *retval = NULL;
1635 	struct sctp_signed_cookie *cookie;
1636 	struct sctp_cookie *bear_cookie;
1637 	int headersize, bodysize, fixed_size;
1638 	__u8 *digest = ep->digest;
1639 	struct scatterlist sg;
1640 	unsigned int keylen, len;
1641 	char *key;
1642 	sctp_scope_t scope;
1643 	struct sk_buff *skb = chunk->skb;
1644 	struct timeval tv;
1645 	struct hash_desc desc;
1646 
1647 	/* Header size is static data prior to the actual cookie, including
1648 	 * any padding.
1649 	 */
1650 	headersize = sizeof(sctp_chunkhdr_t) +
1651 		     (sizeof(struct sctp_signed_cookie) -
1652 		      sizeof(struct sctp_cookie));
1653 	bodysize = ntohs(chunk->chunk_hdr->length) - headersize;
1654 	fixed_size = headersize + sizeof(struct sctp_cookie);
1655 
1656 	/* Verify that the chunk looks like it even has a cookie.
1657 	 * There must be enough room for our cookie and our peer's
1658 	 * INIT chunk.
1659 	 */
1660 	len = ntohs(chunk->chunk_hdr->length);
1661 	if (len < fixed_size + sizeof(struct sctp_chunkhdr))
1662 		goto malformed;
1663 
1664 	/* Verify that the cookie has been padded out. */
1665 	if (bodysize % SCTP_COOKIE_MULTIPLE)
1666 		goto malformed;
1667 
1668 	/* Process the cookie.  */
1669 	cookie = chunk->subh.cookie_hdr;
1670 	bear_cookie = &cookie->c;
1671 
1672 	if (!sctp_sk(ep->base.sk)->hmac)
1673 		goto no_hmac;
1674 
1675 	/* Check the signature.  */
1676 	keylen = SCTP_SECRET_SIZE;
1677 	sg_init_one(&sg, bear_cookie, bodysize);
1678 	key = (char *)ep->secret_key[ep->current_key];
1679 	desc.tfm = sctp_sk(ep->base.sk)->hmac;
1680 	desc.flags = 0;
1681 
1682 	memset(digest, 0x00, SCTP_SIGNATURE_SIZE);
1683 	if (crypto_hash_setkey(desc.tfm, key, keylen) ||
1684 	    crypto_hash_digest(&desc, &sg, bodysize, digest)) {
1685 		*error = -SCTP_IERROR_NOMEM;
1686 		goto fail;
1687 	}
1688 
1689 	if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
1690 		/* Try the previous key. */
1691 		key = (char *)ep->secret_key[ep->last_key];
1692 		memset(digest, 0x00, SCTP_SIGNATURE_SIZE);
1693 		if (crypto_hash_setkey(desc.tfm, key, keylen) ||
1694 		    crypto_hash_digest(&desc, &sg, bodysize, digest)) {
1695 			*error = -SCTP_IERROR_NOMEM;
1696 			goto fail;
1697 		}
1698 
1699 		if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
1700 			/* Yikes!  Still bad signature! */
1701 			*error = -SCTP_IERROR_BAD_SIG;
1702 			goto fail;
1703 		}
1704 	}
1705 
1706 no_hmac:
1707 	/* IG Section 2.35.2:
1708 	 *  3) Compare the port numbers and the verification tag contained
1709 	 *     within the COOKIE ECHO chunk to the actual port numbers and the
1710 	 *     verification tag within the SCTP common header of the received
1711 	 *     packet. If these values do not match the packet MUST be silently
1712 	 *     discarded,
1713 	 */
1714 	if (ntohl(chunk->sctp_hdr->vtag) != bear_cookie->my_vtag) {
1715 		*error = -SCTP_IERROR_BAD_TAG;
1716 		goto fail;
1717 	}
1718 
1719 	if (chunk->sctp_hdr->source != bear_cookie->peer_addr.v4.sin_port ||
1720 	    ntohs(chunk->sctp_hdr->dest) != bear_cookie->my_port) {
1721 		*error = -SCTP_IERROR_BAD_PORTS;
1722 		goto fail;
1723 	}
1724 
1725 	/* Check to see if the cookie is stale.  If there is already
1726 	 * an association, there is no need to check cookie's expiration
1727 	 * for init collision case of lost COOKIE ACK.
1728 	 * If skb has been timestamped, then use the stamp, otherwise
1729 	 * use current time.  This introduces a small possibility that
1730 	 * that a cookie may be considered expired, but his would only slow
1731 	 * down the new association establishment instead of every packet.
1732 	 */
1733 	if (sock_flag(ep->base.sk, SOCK_TIMESTAMP))
1734 		skb_get_timestamp(skb, &tv);
1735 	else
1736 		do_gettimeofday(&tv);
1737 
1738 	if (!asoc && tv_lt(bear_cookie->expiration, tv)) {
1739 		/*
1740 		 * Section 3.3.10.3 Stale Cookie Error (3)
1741 		 *
1742 		 * Cause of error
1743 		 * ---------------
1744 		 * Stale Cookie Error:  Indicates the receipt of a valid State
1745 		 * Cookie that has expired.
1746 		 */
1747 		len = ntohs(chunk->chunk_hdr->length);
1748 		*errp = sctp_make_op_error_space(asoc, chunk, len);
1749 		if (*errp) {
1750 			suseconds_t usecs = (tv.tv_sec -
1751 				bear_cookie->expiration.tv_sec) * 1000000L +
1752 				tv.tv_usec - bear_cookie->expiration.tv_usec;
1753 			__be32 n = htonl(usecs);
1754 
1755 			sctp_init_cause(*errp, SCTP_ERROR_STALE_COOKIE,
1756 					sizeof(n));
1757 			sctp_addto_chunk(*errp, sizeof(n), &n);
1758 			*error = -SCTP_IERROR_STALE_COOKIE;
1759 		} else
1760 			*error = -SCTP_IERROR_NOMEM;
1761 
1762 		goto fail;
1763 	}
1764 
1765 	/* Make a new base association.  */
1766 	scope = sctp_scope(sctp_source(chunk));
1767 	retval = sctp_association_new(ep, ep->base.sk, scope, gfp);
1768 	if (!retval) {
1769 		*error = -SCTP_IERROR_NOMEM;
1770 		goto fail;
1771 	}
1772 
1773 	/* Set up our peer's port number.  */
1774 	retval->peer.port = ntohs(chunk->sctp_hdr->source);
1775 
1776 	/* Populate the association from the cookie.  */
1777 	memcpy(&retval->c, bear_cookie, sizeof(*bear_cookie));
1778 
1779 	if (sctp_assoc_set_bind_addr_from_cookie(retval, bear_cookie,
1780 						 GFP_ATOMIC) < 0) {
1781 		*error = -SCTP_IERROR_NOMEM;
1782 		goto fail;
1783 	}
1784 
1785 	/* Also, add the destination address. */
1786 	if (list_empty(&retval->base.bind_addr.address_list)) {
1787 		sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest,
1788 				SCTP_ADDR_SRC, GFP_ATOMIC);
1789 	}
1790 
1791 	retval->next_tsn = retval->c.initial_tsn;
1792 	retval->ctsn_ack_point = retval->next_tsn - 1;
1793 	retval->addip_serial = retval->c.initial_tsn;
1794 	retval->adv_peer_ack_point = retval->ctsn_ack_point;
1795 	retval->peer.prsctp_capable = retval->c.prsctp_capable;
1796 	retval->peer.adaptation_ind = retval->c.adaptation_ind;
1797 
1798 	/* The INIT stuff will be done by the side effects.  */
1799 	return retval;
1800 
1801 fail:
1802 	if (retval)
1803 		sctp_association_free(retval);
1804 
1805 	return NULL;
1806 
1807 malformed:
1808 	/* Yikes!  The packet is either corrupt or deliberately
1809 	 * malformed.
1810 	 */
1811 	*error = -SCTP_IERROR_MALFORMED;
1812 	goto fail;
1813 }
1814 
1815 /********************************************************************
1816  * 3rd Level Abstractions
1817  ********************************************************************/
1818 
1819 struct __sctp_missing {
1820 	__be32 num_missing;
1821 	__be16 type;
1822 }  __packed;
1823 
1824 /*
1825  * Report a missing mandatory parameter.
1826  */
1827 static int sctp_process_missing_param(const struct sctp_association *asoc,
1828 				      sctp_param_t paramtype,
1829 				      struct sctp_chunk *chunk,
1830 				      struct sctp_chunk **errp)
1831 {
1832 	struct __sctp_missing report;
1833 	__u16 len;
1834 
1835 	len = WORD_ROUND(sizeof(report));
1836 
1837 	/* Make an ERROR chunk, preparing enough room for
1838 	 * returning multiple unknown parameters.
1839 	 */
1840 	if (!*errp)
1841 		*errp = sctp_make_op_error_space(asoc, chunk, len);
1842 
1843 	if (*errp) {
1844 		report.num_missing = htonl(1);
1845 		report.type = paramtype;
1846 		sctp_init_cause(*errp, SCTP_ERROR_MISS_PARAM,
1847 				sizeof(report));
1848 		sctp_addto_chunk(*errp, sizeof(report), &report);
1849 	}
1850 
1851 	/* Stop processing this chunk. */
1852 	return 0;
1853 }
1854 
1855 /* Report an Invalid Mandatory Parameter.  */
1856 static int sctp_process_inv_mandatory(const struct sctp_association *asoc,
1857 				      struct sctp_chunk *chunk,
1858 				      struct sctp_chunk **errp)
1859 {
1860 	/* Invalid Mandatory Parameter Error has no payload. */
1861 
1862 	if (!*errp)
1863 		*errp = sctp_make_op_error_space(asoc, chunk, 0);
1864 
1865 	if (*errp)
1866 		sctp_init_cause(*errp, SCTP_ERROR_INV_PARAM, 0);
1867 
1868 	/* Stop processing this chunk. */
1869 	return 0;
1870 }
1871 
1872 static int sctp_process_inv_paramlength(const struct sctp_association *asoc,
1873 					struct sctp_paramhdr *param,
1874 					const struct sctp_chunk *chunk,
1875 					struct sctp_chunk **errp)
1876 {
1877 	/* This is a fatal error.  Any accumulated non-fatal errors are
1878 	 * not reported.
1879 	 */
1880 	if (*errp)
1881 		sctp_chunk_free(*errp);
1882 
1883 	/* Create an error chunk and fill it in with our payload. */
1884 	*errp = sctp_make_violation_paramlen(asoc, chunk, param);
1885 
1886 	return 0;
1887 }
1888 
1889 
1890 /* Do not attempt to handle the HOST_NAME parm.  However, do
1891  * send back an indicator to the peer.
1892  */
1893 static int sctp_process_hn_param(const struct sctp_association *asoc,
1894 				 union sctp_params param,
1895 				 struct sctp_chunk *chunk,
1896 				 struct sctp_chunk **errp)
1897 {
1898 	__u16 len = ntohs(param.p->length);
1899 
1900 	/* Processing of the HOST_NAME parameter will generate an
1901 	 * ABORT.  If we've accumulated any non-fatal errors, they
1902 	 * would be unrecognized parameters and we should not include
1903 	 * them in the ABORT.
1904 	 */
1905 	if (*errp)
1906 		sctp_chunk_free(*errp);
1907 
1908 	*errp = sctp_make_op_error_space(asoc, chunk, len);
1909 
1910 	if (*errp) {
1911 		sctp_init_cause(*errp, SCTP_ERROR_DNS_FAILED, len);
1912 		sctp_addto_chunk(*errp, len, param.v);
1913 	}
1914 
1915 	/* Stop processing this chunk. */
1916 	return 0;
1917 }
1918 
1919 static int sctp_verify_ext_param(union sctp_params param)
1920 {
1921 	__u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
1922 	int have_auth = 0;
1923 	int have_asconf = 0;
1924 	int i;
1925 
1926 	for (i = 0; i < num_ext; i++) {
1927 		switch (param.ext->chunks[i]) {
1928 		    case SCTP_CID_AUTH:
1929 			    have_auth = 1;
1930 			    break;
1931 		    case SCTP_CID_ASCONF:
1932 		    case SCTP_CID_ASCONF_ACK:
1933 			    have_asconf = 1;
1934 			    break;
1935 		}
1936 	}
1937 
1938 	/* ADD-IP Security: The draft requires us to ABORT or ignore the
1939 	 * INIT/INIT-ACK if ADD-IP is listed, but AUTH is not.  Do this
1940 	 * only if ADD-IP is turned on and we are not backward-compatible
1941 	 * mode.
1942 	 */
1943 	if (sctp_addip_noauth)
1944 		return 1;
1945 
1946 	if (sctp_addip_enable && !have_auth && have_asconf)
1947 		return 0;
1948 
1949 	return 1;
1950 }
1951 
1952 static void sctp_process_ext_param(struct sctp_association *asoc,
1953 				    union sctp_params param)
1954 {
1955 	__u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
1956 	int i;
1957 
1958 	for (i = 0; i < num_ext; i++) {
1959 		switch (param.ext->chunks[i]) {
1960 		    case SCTP_CID_FWD_TSN:
1961 			    if (sctp_prsctp_enable &&
1962 				!asoc->peer.prsctp_capable)
1963 				    asoc->peer.prsctp_capable = 1;
1964 			    break;
1965 		    case SCTP_CID_AUTH:
1966 			    /* if the peer reports AUTH, assume that he
1967 			     * supports AUTH.
1968 			     */
1969 			    if (sctp_auth_enable)
1970 				    asoc->peer.auth_capable = 1;
1971 			    break;
1972 		    case SCTP_CID_ASCONF:
1973 		    case SCTP_CID_ASCONF_ACK:
1974 			    if (sctp_addip_enable)
1975 				    asoc->peer.asconf_capable = 1;
1976 			    break;
1977 		    default:
1978 			    break;
1979 		}
1980 	}
1981 }
1982 
1983 /* RFC 3.2.1 & the Implementers Guide 2.2.
1984  *
1985  * The Parameter Types are encoded such that the
1986  * highest-order two bits specify the action that must be
1987  * taken if the processing endpoint does not recognize the
1988  * Parameter Type.
1989  *
1990  * 00 - Stop processing this parameter; do not process any further
1991  * 	parameters within this chunk
1992  *
1993  * 01 - Stop processing this parameter, do not process any further
1994  *	parameters within this chunk, and report the unrecognized
1995  *	parameter in an 'Unrecognized Parameter' ERROR chunk.
1996  *
1997  * 10 - Skip this parameter and continue processing.
1998  *
1999  * 11 - Skip this parameter and continue processing but
2000  *	report the unrecognized parameter in an
2001  *	'Unrecognized Parameter' ERROR chunk.
2002  *
2003  * Return value:
2004  * 	SCTP_IERROR_NO_ERROR - continue with the chunk
2005  * 	SCTP_IERROR_ERROR    - stop and report an error.
2006  * 	SCTP_IERROR_NOMEME   - out of memory.
2007  */
2008 static sctp_ierror_t sctp_process_unk_param(const struct sctp_association *asoc,
2009 					    union sctp_params param,
2010 					    struct sctp_chunk *chunk,
2011 					    struct sctp_chunk **errp)
2012 {
2013 	int retval = SCTP_IERROR_NO_ERROR;
2014 
2015 	switch (param.p->type & SCTP_PARAM_ACTION_MASK) {
2016 	case SCTP_PARAM_ACTION_DISCARD:
2017 		retval =  SCTP_IERROR_ERROR;
2018 		break;
2019 	case SCTP_PARAM_ACTION_SKIP:
2020 		break;
2021 	case SCTP_PARAM_ACTION_DISCARD_ERR:
2022 		retval =  SCTP_IERROR_ERROR;
2023 		/* Fall through */
2024 	case SCTP_PARAM_ACTION_SKIP_ERR:
2025 		/* Make an ERROR chunk, preparing enough room for
2026 		 * returning multiple unknown parameters.
2027 		 */
2028 		if (NULL == *errp)
2029 			*errp = sctp_make_op_error_fixed(asoc, chunk);
2030 
2031 		if (*errp) {
2032 			if (!sctp_init_cause_fixed(*errp, SCTP_ERROR_UNKNOWN_PARAM,
2033 					WORD_ROUND(ntohs(param.p->length))))
2034 				sctp_addto_chunk_fixed(*errp,
2035 						WORD_ROUND(ntohs(param.p->length)),
2036 						param.v);
2037 		} else {
2038 			/* If there is no memory for generating the ERROR
2039 			 * report as specified, an ABORT will be triggered
2040 			 * to the peer and the association won't be
2041 			 * established.
2042 			 */
2043 			retval = SCTP_IERROR_NOMEM;
2044 		}
2045 		break;
2046 	default:
2047 		break;
2048 	}
2049 
2050 	return retval;
2051 }
2052 
2053 /* Verify variable length parameters
2054  * Return values:
2055  * 	SCTP_IERROR_ABORT - trigger an ABORT
2056  * 	SCTP_IERROR_NOMEM - out of memory (abort)
2057  *	SCTP_IERROR_ERROR - stop processing, trigger an ERROR
2058  * 	SCTP_IERROR_NO_ERROR - continue with the chunk
2059  */
2060 static sctp_ierror_t sctp_verify_param(const struct sctp_association *asoc,
2061 					union sctp_params param,
2062 					sctp_cid_t cid,
2063 					struct sctp_chunk *chunk,
2064 					struct sctp_chunk **err_chunk)
2065 {
2066 	struct sctp_hmac_algo_param *hmacs;
2067 	int retval = SCTP_IERROR_NO_ERROR;
2068 	__u16 n_elt, id = 0;
2069 	int i;
2070 
2071 	/* FIXME - This routine is not looking at each parameter per the
2072 	 * chunk type, i.e., unrecognized parameters should be further
2073 	 * identified based on the chunk id.
2074 	 */
2075 
2076 	switch (param.p->type) {
2077 	case SCTP_PARAM_IPV4_ADDRESS:
2078 	case SCTP_PARAM_IPV6_ADDRESS:
2079 	case SCTP_PARAM_COOKIE_PRESERVATIVE:
2080 	case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2081 	case SCTP_PARAM_STATE_COOKIE:
2082 	case SCTP_PARAM_HEARTBEAT_INFO:
2083 	case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2084 	case SCTP_PARAM_ECN_CAPABLE:
2085 	case SCTP_PARAM_ADAPTATION_LAYER_IND:
2086 		break;
2087 
2088 	case SCTP_PARAM_SUPPORTED_EXT:
2089 		if (!sctp_verify_ext_param(param))
2090 			return SCTP_IERROR_ABORT;
2091 		break;
2092 
2093 	case SCTP_PARAM_SET_PRIMARY:
2094 		if (sctp_addip_enable)
2095 			break;
2096 		goto fallthrough;
2097 
2098 	case SCTP_PARAM_HOST_NAME_ADDRESS:
2099 		/* Tell the peer, we won't support this param.  */
2100 		sctp_process_hn_param(asoc, param, chunk, err_chunk);
2101 		retval = SCTP_IERROR_ABORT;
2102 		break;
2103 
2104 	case SCTP_PARAM_FWD_TSN_SUPPORT:
2105 		if (sctp_prsctp_enable)
2106 			break;
2107 		goto fallthrough;
2108 
2109 	case SCTP_PARAM_RANDOM:
2110 		if (!sctp_auth_enable)
2111 			goto fallthrough;
2112 
2113 		/* SCTP-AUTH: Secion 6.1
2114 		 * If the random number is not 32 byte long the association
2115 		 * MUST be aborted.  The ABORT chunk SHOULD contain the error
2116 		 * cause 'Protocol Violation'.
2117 		 */
2118 		if (SCTP_AUTH_RANDOM_LENGTH !=
2119 			ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) {
2120 			sctp_process_inv_paramlength(asoc, param.p,
2121 							chunk, err_chunk);
2122 			retval = SCTP_IERROR_ABORT;
2123 		}
2124 		break;
2125 
2126 	case SCTP_PARAM_CHUNKS:
2127 		if (!sctp_auth_enable)
2128 			goto fallthrough;
2129 
2130 		/* SCTP-AUTH: Section 3.2
2131 		 * The CHUNKS parameter MUST be included once in the INIT or
2132 		 *  INIT-ACK chunk if the sender wants to receive authenticated
2133 		 *  chunks.  Its maximum length is 260 bytes.
2134 		 */
2135 		if (260 < ntohs(param.p->length)) {
2136 			sctp_process_inv_paramlength(asoc, param.p,
2137 						     chunk, err_chunk);
2138 			retval = SCTP_IERROR_ABORT;
2139 		}
2140 		break;
2141 
2142 	case SCTP_PARAM_HMAC_ALGO:
2143 		if (!sctp_auth_enable)
2144 			goto fallthrough;
2145 
2146 		hmacs = (struct sctp_hmac_algo_param *)param.p;
2147 		n_elt = (ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) >> 1;
2148 
2149 		/* SCTP-AUTH: Section 6.1
2150 		 * The HMAC algorithm based on SHA-1 MUST be supported and
2151 		 * included in the HMAC-ALGO parameter.
2152 		 */
2153 		for (i = 0; i < n_elt; i++) {
2154 			id = ntohs(hmacs->hmac_ids[i]);
2155 
2156 			if (id == SCTP_AUTH_HMAC_ID_SHA1)
2157 				break;
2158 		}
2159 
2160 		if (id != SCTP_AUTH_HMAC_ID_SHA1) {
2161 			sctp_process_inv_paramlength(asoc, param.p, chunk,
2162 						     err_chunk);
2163 			retval = SCTP_IERROR_ABORT;
2164 		}
2165 		break;
2166 fallthrough:
2167 	default:
2168 		SCTP_DEBUG_PRINTK("Unrecognized param: %d for chunk %d.\n",
2169 				ntohs(param.p->type), cid);
2170 		retval = sctp_process_unk_param(asoc, param, chunk, err_chunk);
2171 		break;
2172 	}
2173 	return retval;
2174 }
2175 
2176 /* Verify the INIT packet before we process it.  */
2177 int sctp_verify_init(const struct sctp_association *asoc,
2178 		     sctp_cid_t cid,
2179 		     sctp_init_chunk_t *peer_init,
2180 		     struct sctp_chunk *chunk,
2181 		     struct sctp_chunk **errp)
2182 {
2183 	union sctp_params param;
2184 	int has_cookie = 0;
2185 	int result;
2186 
2187 	/* Verify stream values are non-zero. */
2188 	if ((0 == peer_init->init_hdr.num_outbound_streams) ||
2189 	    (0 == peer_init->init_hdr.num_inbound_streams) ||
2190 	    (0 == peer_init->init_hdr.init_tag) ||
2191 	    (SCTP_DEFAULT_MINWINDOW > ntohl(peer_init->init_hdr.a_rwnd))) {
2192 
2193 		return sctp_process_inv_mandatory(asoc, chunk, errp);
2194 	}
2195 
2196 	/* Check for missing mandatory parameters.  */
2197 	sctp_walk_params(param, peer_init, init_hdr.params) {
2198 
2199 		if (SCTP_PARAM_STATE_COOKIE == param.p->type)
2200 			has_cookie = 1;
2201 
2202 	} /* for (loop through all parameters) */
2203 
2204 	/* There is a possibility that a parameter length was bad and
2205 	 * in that case we would have stoped walking the parameters.
2206 	 * The current param.p would point at the bad one.
2207 	 * Current consensus on the mailing list is to generate a PROTOCOL
2208 	 * VIOLATION error.  We build the ERROR chunk here and let the normal
2209 	 * error handling code build and send the packet.
2210 	 */
2211 	if (param.v != (void*)chunk->chunk_end)
2212 		return sctp_process_inv_paramlength(asoc, param.p, chunk, errp);
2213 
2214 	/* The only missing mandatory param possible today is
2215 	 * the state cookie for an INIT-ACK chunk.
2216 	 */
2217 	if ((SCTP_CID_INIT_ACK == cid) && !has_cookie)
2218 		return sctp_process_missing_param(asoc, SCTP_PARAM_STATE_COOKIE,
2219 						  chunk, errp);
2220 
2221 	/* Verify all the variable length parameters */
2222 	sctp_walk_params(param, peer_init, init_hdr.params) {
2223 
2224 		result = sctp_verify_param(asoc, param, cid, chunk, errp);
2225 		switch (result) {
2226 		    case SCTP_IERROR_ABORT:
2227 		    case SCTP_IERROR_NOMEM:
2228 				return 0;
2229 		    case SCTP_IERROR_ERROR:
2230 				return 1;
2231 		    case SCTP_IERROR_NO_ERROR:
2232 		    default:
2233 				break;
2234 		}
2235 
2236 	} /* for (loop through all parameters) */
2237 
2238 	return 1;
2239 }
2240 
2241 /* Unpack the parameters in an INIT packet into an association.
2242  * Returns 0 on failure, else success.
2243  * FIXME:  This is an association method.
2244  */
2245 int sctp_process_init(struct sctp_association *asoc, sctp_cid_t cid,
2246 		      const union sctp_addr *peer_addr,
2247 		      sctp_init_chunk_t *peer_init, gfp_t gfp)
2248 {
2249 	union sctp_params param;
2250 	struct sctp_transport *transport;
2251 	struct list_head *pos, *temp;
2252 	char *cookie;
2253 
2254 	/* We must include the address that the INIT packet came from.
2255 	 * This is the only address that matters for an INIT packet.
2256 	 * When processing a COOKIE ECHO, we retrieve the from address
2257 	 * of the INIT from the cookie.
2258 	 */
2259 
2260 	/* This implementation defaults to making the first transport
2261 	 * added as the primary transport.  The source address seems to
2262 	 * be a a better choice than any of the embedded addresses.
2263 	 */
2264 	if (peer_addr) {
2265 		if(!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
2266 			goto nomem;
2267 	}
2268 
2269 	/* Process the initialization parameters.  */
2270 	sctp_walk_params(param, peer_init, init_hdr.params) {
2271 
2272 		if (!sctp_process_param(asoc, param, peer_addr, gfp))
2273 			goto clean_up;
2274 	}
2275 
2276 	/* AUTH: After processing the parameters, make sure that we
2277 	 * have all the required info to potentially do authentications.
2278 	 */
2279 	if (asoc->peer.auth_capable && (!asoc->peer.peer_random ||
2280 					!asoc->peer.peer_hmacs))
2281 		asoc->peer.auth_capable = 0;
2282 
2283 	/* In a non-backward compatible mode, if the peer claims
2284 	 * support for ADD-IP but not AUTH,  the ADD-IP spec states
2285 	 * that we MUST ABORT the association. Section 6.  The section
2286 	 * also give us an option to silently ignore the packet, which
2287 	 * is what we'll do here.
2288 	 */
2289 	if (!sctp_addip_noauth &&
2290 	     (asoc->peer.asconf_capable && !asoc->peer.auth_capable)) {
2291 		asoc->peer.addip_disabled_mask |= (SCTP_PARAM_ADD_IP |
2292 						  SCTP_PARAM_DEL_IP |
2293 						  SCTP_PARAM_SET_PRIMARY);
2294 		asoc->peer.asconf_capable = 0;
2295 		goto clean_up;
2296 	}
2297 
2298 	/* Walk list of transports, removing transports in the UNKNOWN state. */
2299 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2300 		transport = list_entry(pos, struct sctp_transport, transports);
2301 		if (transport->state == SCTP_UNKNOWN) {
2302 			sctp_assoc_rm_peer(asoc, transport);
2303 		}
2304 	}
2305 
2306 	/* The fixed INIT headers are always in network byte
2307 	 * order.
2308 	 */
2309 	asoc->peer.i.init_tag =
2310 		ntohl(peer_init->init_hdr.init_tag);
2311 	asoc->peer.i.a_rwnd =
2312 		ntohl(peer_init->init_hdr.a_rwnd);
2313 	asoc->peer.i.num_outbound_streams =
2314 		ntohs(peer_init->init_hdr.num_outbound_streams);
2315 	asoc->peer.i.num_inbound_streams =
2316 		ntohs(peer_init->init_hdr.num_inbound_streams);
2317 	asoc->peer.i.initial_tsn =
2318 		ntohl(peer_init->init_hdr.initial_tsn);
2319 
2320 	/* Apply the upper bounds for output streams based on peer's
2321 	 * number of inbound streams.
2322 	 */
2323 	if (asoc->c.sinit_num_ostreams  >
2324 	    ntohs(peer_init->init_hdr.num_inbound_streams)) {
2325 		asoc->c.sinit_num_ostreams =
2326 			ntohs(peer_init->init_hdr.num_inbound_streams);
2327 	}
2328 
2329 	if (asoc->c.sinit_max_instreams >
2330 	    ntohs(peer_init->init_hdr.num_outbound_streams)) {
2331 		asoc->c.sinit_max_instreams =
2332 			ntohs(peer_init->init_hdr.num_outbound_streams);
2333 	}
2334 
2335 	/* Copy Initiation tag from INIT to VT_peer in cookie.   */
2336 	asoc->c.peer_vtag = asoc->peer.i.init_tag;
2337 
2338 	/* Peer Rwnd   : Current calculated value of the peer's rwnd.  */
2339 	asoc->peer.rwnd = asoc->peer.i.a_rwnd;
2340 
2341 	/* Copy cookie in case we need to resend COOKIE-ECHO. */
2342 	cookie = asoc->peer.cookie;
2343 	if (cookie) {
2344 		asoc->peer.cookie = kmemdup(cookie, asoc->peer.cookie_len, gfp);
2345 		if (!asoc->peer.cookie)
2346 			goto clean_up;
2347 	}
2348 
2349 	/* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily
2350 	 * high (for example, implementations MAY use the size of the receiver
2351 	 * advertised window).
2352 	 */
2353 	list_for_each_entry(transport, &asoc->peer.transport_addr_list,
2354 			transports) {
2355 		transport->ssthresh = asoc->peer.i.a_rwnd;
2356 	}
2357 
2358 	/* Set up the TSN tracking pieces.  */
2359 	if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
2360 				asoc->peer.i.initial_tsn, gfp))
2361 		goto clean_up;
2362 
2363 	/* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
2364 	 *
2365 	 * The stream sequence number in all the streams shall start
2366 	 * from 0 when the association is established.  Also, when the
2367 	 * stream sequence number reaches the value 65535 the next
2368 	 * stream sequence number shall be set to 0.
2369 	 */
2370 
2371 	/* Allocate storage for the negotiated streams if it is not a temporary
2372 	 * association.
2373 	 */
2374 	if (!asoc->temp) {
2375 		int error;
2376 
2377 		asoc->ssnmap = sctp_ssnmap_new(asoc->c.sinit_max_instreams,
2378 					       asoc->c.sinit_num_ostreams, gfp);
2379 		if (!asoc->ssnmap)
2380 			goto clean_up;
2381 
2382 		error = sctp_assoc_set_id(asoc, gfp);
2383 		if (error)
2384 			goto clean_up;
2385 	}
2386 
2387 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
2388 	 *
2389 	 * When an endpoint has an ASCONF signaled change to be sent to the
2390 	 * remote endpoint it should do the following:
2391 	 * ...
2392 	 * A2) A serial number should be assigned to the Chunk. The serial
2393 	 * number should be a monotonically increasing number. All serial
2394 	 * numbers are defined to be initialized at the start of the
2395 	 * association to the same value as the Initial TSN.
2396 	 */
2397 	asoc->peer.addip_serial = asoc->peer.i.initial_tsn - 1;
2398 	return 1;
2399 
2400 clean_up:
2401 	/* Release the transport structures. */
2402 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2403 		transport = list_entry(pos, struct sctp_transport, transports);
2404 		if (transport->state != SCTP_ACTIVE)
2405 			sctp_assoc_rm_peer(asoc, transport);
2406 	}
2407 
2408 nomem:
2409 	return 0;
2410 }
2411 
2412 
2413 /* Update asoc with the option described in param.
2414  *
2415  * RFC2960 3.3.2.1 Optional/Variable Length Parameters in INIT
2416  *
2417  * asoc is the association to update.
2418  * param is the variable length parameter to use for update.
2419  * cid tells us if this is an INIT, INIT ACK or COOKIE ECHO.
2420  * If the current packet is an INIT we want to minimize the amount of
2421  * work we do.  In particular, we should not build transport
2422  * structures for the addresses.
2423  */
2424 static int sctp_process_param(struct sctp_association *asoc,
2425 			      union sctp_params param,
2426 			      const union sctp_addr *peer_addr,
2427 			      gfp_t gfp)
2428 {
2429 	union sctp_addr addr;
2430 	int i;
2431 	__u16 sat;
2432 	int retval = 1;
2433 	sctp_scope_t scope;
2434 	time_t stale;
2435 	struct sctp_af *af;
2436 	union sctp_addr_param *addr_param;
2437 	struct sctp_transport *t;
2438 
2439 	/* We maintain all INIT parameters in network byte order all the
2440 	 * time.  This allows us to not worry about whether the parameters
2441 	 * came from a fresh INIT, and INIT ACK, or were stored in a cookie.
2442 	 */
2443 	switch (param.p->type) {
2444 	case SCTP_PARAM_IPV6_ADDRESS:
2445 		if (PF_INET6 != asoc->base.sk->sk_family)
2446 			break;
2447 		goto do_addr_param;
2448 
2449 	case SCTP_PARAM_IPV4_ADDRESS:
2450 		/* v4 addresses are not allowed on v6-only socket */
2451 		if (ipv6_only_sock(asoc->base.sk))
2452 			break;
2453 do_addr_param:
2454 		af = sctp_get_af_specific(param_type2af(param.p->type));
2455 		af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
2456 		scope = sctp_scope(peer_addr);
2457 		if (sctp_in_scope(&addr, scope))
2458 			if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
2459 				return 0;
2460 		break;
2461 
2462 	case SCTP_PARAM_COOKIE_PRESERVATIVE:
2463 		if (!sctp_cookie_preserve_enable)
2464 			break;
2465 
2466 		stale = ntohl(param.life->lifespan_increment);
2467 
2468 		/* Suggested Cookie Life span increment's unit is msec,
2469 		 * (1/1000sec).
2470 		 */
2471 		asoc->cookie_life.tv_sec += stale / 1000;
2472 		asoc->cookie_life.tv_usec += (stale % 1000) * 1000;
2473 		break;
2474 
2475 	case SCTP_PARAM_HOST_NAME_ADDRESS:
2476 		SCTP_DEBUG_PRINTK("unimplemented SCTP_HOST_NAME_ADDRESS\n");
2477 		break;
2478 
2479 	case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2480 		/* Turn off the default values first so we'll know which
2481 		 * ones are really set by the peer.
2482 		 */
2483 		asoc->peer.ipv4_address = 0;
2484 		asoc->peer.ipv6_address = 0;
2485 
2486 		/* Assume that peer supports the address family
2487 		 * by which it sends a packet.
2488 		 */
2489 		if (peer_addr->sa.sa_family == AF_INET6)
2490 			asoc->peer.ipv6_address = 1;
2491 		else if (peer_addr->sa.sa_family == AF_INET)
2492 			asoc->peer.ipv4_address = 1;
2493 
2494 		/* Cycle through address types; avoid divide by 0. */
2495 		sat = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2496 		if (sat)
2497 			sat /= sizeof(__u16);
2498 
2499 		for (i = 0; i < sat; ++i) {
2500 			switch (param.sat->types[i]) {
2501 			case SCTP_PARAM_IPV4_ADDRESS:
2502 				asoc->peer.ipv4_address = 1;
2503 				break;
2504 
2505 			case SCTP_PARAM_IPV6_ADDRESS:
2506 				if (PF_INET6 == asoc->base.sk->sk_family)
2507 					asoc->peer.ipv6_address = 1;
2508 				break;
2509 
2510 			case SCTP_PARAM_HOST_NAME_ADDRESS:
2511 				asoc->peer.hostname_address = 1;
2512 				break;
2513 
2514 			default: /* Just ignore anything else.  */
2515 				break;
2516 			}
2517 		}
2518 		break;
2519 
2520 	case SCTP_PARAM_STATE_COOKIE:
2521 		asoc->peer.cookie_len =
2522 			ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2523 		asoc->peer.cookie = param.cookie->body;
2524 		break;
2525 
2526 	case SCTP_PARAM_HEARTBEAT_INFO:
2527 		/* Would be odd to receive, but it causes no problems. */
2528 		break;
2529 
2530 	case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2531 		/* Rejected during verify stage. */
2532 		break;
2533 
2534 	case SCTP_PARAM_ECN_CAPABLE:
2535 		asoc->peer.ecn_capable = 1;
2536 		break;
2537 
2538 	case SCTP_PARAM_ADAPTATION_LAYER_IND:
2539 		asoc->peer.adaptation_ind = ntohl(param.aind->adaptation_ind);
2540 		break;
2541 
2542 	case SCTP_PARAM_SET_PRIMARY:
2543 		if (!sctp_addip_enable)
2544 			goto fall_through;
2545 
2546 		addr_param = param.v + sizeof(sctp_addip_param_t);
2547 
2548 		af = sctp_get_af_specific(param_type2af(param.p->type));
2549 		af->from_addr_param(&addr, addr_param,
2550 				    htons(asoc->peer.port), 0);
2551 
2552 		/* if the address is invalid, we can't process it.
2553 		 * XXX: see spec for what to do.
2554 		 */
2555 		if (!af->addr_valid(&addr, NULL, NULL))
2556 			break;
2557 
2558 		t = sctp_assoc_lookup_paddr(asoc, &addr);
2559 		if (!t)
2560 			break;
2561 
2562 		sctp_assoc_set_primary(asoc, t);
2563 		break;
2564 
2565 	case SCTP_PARAM_SUPPORTED_EXT:
2566 		sctp_process_ext_param(asoc, param);
2567 		break;
2568 
2569 	case SCTP_PARAM_FWD_TSN_SUPPORT:
2570 		if (sctp_prsctp_enable) {
2571 			asoc->peer.prsctp_capable = 1;
2572 			break;
2573 		}
2574 		/* Fall Through */
2575 		goto fall_through;
2576 
2577 	case SCTP_PARAM_RANDOM:
2578 		if (!sctp_auth_enable)
2579 			goto fall_through;
2580 
2581 		/* Save peer's random parameter */
2582 		asoc->peer.peer_random = kmemdup(param.p,
2583 					    ntohs(param.p->length), gfp);
2584 		if (!asoc->peer.peer_random) {
2585 			retval = 0;
2586 			break;
2587 		}
2588 		break;
2589 
2590 	case SCTP_PARAM_HMAC_ALGO:
2591 		if (!sctp_auth_enable)
2592 			goto fall_through;
2593 
2594 		/* Save peer's HMAC list */
2595 		asoc->peer.peer_hmacs = kmemdup(param.p,
2596 					    ntohs(param.p->length), gfp);
2597 		if (!asoc->peer.peer_hmacs) {
2598 			retval = 0;
2599 			break;
2600 		}
2601 
2602 		/* Set the default HMAC the peer requested*/
2603 		sctp_auth_asoc_set_default_hmac(asoc, param.hmac_algo);
2604 		break;
2605 
2606 	case SCTP_PARAM_CHUNKS:
2607 		if (!sctp_auth_enable)
2608 			goto fall_through;
2609 
2610 		asoc->peer.peer_chunks = kmemdup(param.p,
2611 					    ntohs(param.p->length), gfp);
2612 		if (!asoc->peer.peer_chunks)
2613 			retval = 0;
2614 		break;
2615 fall_through:
2616 	default:
2617 		/* Any unrecognized parameters should have been caught
2618 		 * and handled by sctp_verify_param() which should be
2619 		 * called prior to this routine.  Simply log the error
2620 		 * here.
2621 		 */
2622 		SCTP_DEBUG_PRINTK("Ignoring param: %d for association %p.\n",
2623 				  ntohs(param.p->type), asoc);
2624 		break;
2625 	}
2626 
2627 	return retval;
2628 }
2629 
2630 /* Select a new verification tag.  */
2631 __u32 sctp_generate_tag(const struct sctp_endpoint *ep)
2632 {
2633 	/* I believe that this random number generator complies with RFC1750.
2634 	 * A tag of 0 is reserved for special cases (e.g. INIT).
2635 	 */
2636 	__u32 x;
2637 
2638 	do {
2639 		get_random_bytes(&x, sizeof(__u32));
2640 	} while (x == 0);
2641 
2642 	return x;
2643 }
2644 
2645 /* Select an initial TSN to send during startup.  */
2646 __u32 sctp_generate_tsn(const struct sctp_endpoint *ep)
2647 {
2648 	__u32 retval;
2649 
2650 	get_random_bytes(&retval, sizeof(__u32));
2651 	return retval;
2652 }
2653 
2654 /*
2655  * ADDIP 3.1.1 Address Configuration Change Chunk (ASCONF)
2656  *      0                   1                   2                   3
2657  *      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
2658  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2659  *     | Type = 0xC1   |  Chunk Flags  |      Chunk Length             |
2660  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2661  *     |                       Serial Number                           |
2662  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2663  *     |                    Address Parameter                          |
2664  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2665  *     |                     ASCONF Parameter #1                       |
2666  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2667  *     \                                                               \
2668  *     /                             ....                              /
2669  *     \                                                               \
2670  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2671  *     |                     ASCONF Parameter #N                       |
2672  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2673  *
2674  * Address Parameter and other parameter will not be wrapped in this function
2675  */
2676 static struct sctp_chunk *sctp_make_asconf(struct sctp_association *asoc,
2677 					   union sctp_addr *addr,
2678 					   int vparam_len)
2679 {
2680 	sctp_addiphdr_t asconf;
2681 	struct sctp_chunk *retval;
2682 	int length = sizeof(asconf) + vparam_len;
2683 	union sctp_addr_param addrparam;
2684 	int addrlen;
2685 	struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
2686 
2687 	addrlen = af->to_addr_param(addr, &addrparam);
2688 	if (!addrlen)
2689 		return NULL;
2690 	length += addrlen;
2691 
2692 	/* Create the chunk.  */
2693 	retval = sctp_make_chunk(asoc, SCTP_CID_ASCONF, 0, length);
2694 	if (!retval)
2695 		return NULL;
2696 
2697 	asconf.serial = htonl(asoc->addip_serial++);
2698 
2699 	retval->subh.addip_hdr =
2700 		sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2701 	retval->param_hdr.v =
2702 		sctp_addto_chunk(retval, addrlen, &addrparam);
2703 
2704 	return retval;
2705 }
2706 
2707 /* ADDIP
2708  * 3.2.1 Add IP Address
2709  * 	0                   1                   2                   3
2710  * 	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
2711  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2712  *     |        Type = 0xC001          |    Length = Variable          |
2713  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2714  *     |               ASCONF-Request Correlation ID                   |
2715  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2716  *     |                       Address Parameter                       |
2717  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2718  *
2719  * 3.2.2 Delete IP Address
2720  * 	0                   1                   2                   3
2721  * 	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
2722  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2723  *     |        Type = 0xC002          |    Length = Variable          |
2724  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2725  *     |               ASCONF-Request Correlation ID                   |
2726  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2727  *     |                       Address Parameter                       |
2728  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2729  *
2730  */
2731 struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *asoc,
2732 					      union sctp_addr	      *laddr,
2733 					      struct sockaddr	      *addrs,
2734 					      int		      addrcnt,
2735 					      __be16		      flags)
2736 {
2737 	sctp_addip_param_t	param;
2738 	struct sctp_chunk	*retval;
2739 	union sctp_addr_param	addr_param;
2740 	union sctp_addr		*addr;
2741 	void			*addr_buf;
2742 	struct sctp_af		*af;
2743 	int			paramlen = sizeof(param);
2744 	int			addr_param_len = 0;
2745 	int 			totallen = 0;
2746 	int 			i;
2747 
2748 	/* Get total length of all the address parameters. */
2749 	addr_buf = addrs;
2750 	for (i = 0; i < addrcnt; i++) {
2751 		addr = (union sctp_addr *)addr_buf;
2752 		af = sctp_get_af_specific(addr->v4.sin_family);
2753 		addr_param_len = af->to_addr_param(addr, &addr_param);
2754 
2755 		totallen += paramlen;
2756 		totallen += addr_param_len;
2757 
2758 		addr_buf += af->sockaddr_len;
2759 	}
2760 
2761 	/* Create an asconf chunk with the required length. */
2762 	retval = sctp_make_asconf(asoc, laddr, totallen);
2763 	if (!retval)
2764 		return NULL;
2765 
2766 	/* Add the address parameters to the asconf chunk. */
2767 	addr_buf = addrs;
2768 	for (i = 0; i < addrcnt; i++) {
2769 		addr = (union sctp_addr *)addr_buf;
2770 		af = sctp_get_af_specific(addr->v4.sin_family);
2771 		addr_param_len = af->to_addr_param(addr, &addr_param);
2772 		param.param_hdr.type = flags;
2773 		param.param_hdr.length = htons(paramlen + addr_param_len);
2774 		param.crr_id = i;
2775 
2776 		sctp_addto_chunk(retval, paramlen, &param);
2777 		sctp_addto_chunk(retval, addr_param_len, &addr_param);
2778 
2779 		addr_buf += af->sockaddr_len;
2780 	}
2781 	return retval;
2782 }
2783 
2784 /* ADDIP
2785  * 3.2.4 Set Primary IP Address
2786  *	0                   1                   2                   3
2787  *	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
2788  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2789  *     |        Type =0xC004           |    Length = Variable          |
2790  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2791  *     |               ASCONF-Request Correlation ID                   |
2792  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2793  *     |                       Address Parameter                       |
2794  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2795  *
2796  * Create an ASCONF chunk with Set Primary IP address parameter.
2797  */
2798 struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
2799 					     union sctp_addr *addr)
2800 {
2801 	sctp_addip_param_t	param;
2802 	struct sctp_chunk 	*retval;
2803 	int 			len = sizeof(param);
2804 	union sctp_addr_param	addrparam;
2805 	int			addrlen;
2806 	struct sctp_af		*af = sctp_get_af_specific(addr->v4.sin_family);
2807 
2808 	addrlen = af->to_addr_param(addr, &addrparam);
2809 	if (!addrlen)
2810 		return NULL;
2811 	len += addrlen;
2812 
2813 	/* Create the chunk and make asconf header. */
2814 	retval = sctp_make_asconf(asoc, addr, len);
2815 	if (!retval)
2816 		return NULL;
2817 
2818 	param.param_hdr.type = SCTP_PARAM_SET_PRIMARY;
2819 	param.param_hdr.length = htons(len);
2820 	param.crr_id = 0;
2821 
2822 	sctp_addto_chunk(retval, sizeof(param), &param);
2823 	sctp_addto_chunk(retval, addrlen, &addrparam);
2824 
2825 	return retval;
2826 }
2827 
2828 /* ADDIP 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
2829  *      0                   1                   2                   3
2830  *      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
2831  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2832  *     | Type = 0x80   |  Chunk Flags  |      Chunk Length             |
2833  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2834  *     |                       Serial Number                           |
2835  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2836  *     |                 ASCONF Parameter Response#1                   |
2837  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2838  *     \                                                               \
2839  *     /                             ....                              /
2840  *     \                                                               \
2841  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2842  *     |                 ASCONF Parameter Response#N                   |
2843  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2844  *
2845  * Create an ASCONF_ACK chunk with enough space for the parameter responses.
2846  */
2847 static struct sctp_chunk *sctp_make_asconf_ack(const struct sctp_association *asoc,
2848 					       __u32 serial, int vparam_len)
2849 {
2850 	sctp_addiphdr_t		asconf;
2851 	struct sctp_chunk	*retval;
2852 	int			length = sizeof(asconf) + vparam_len;
2853 
2854 	/* Create the chunk.  */
2855 	retval = sctp_make_chunk(asoc, SCTP_CID_ASCONF_ACK, 0, length);
2856 	if (!retval)
2857 		return NULL;
2858 
2859 	asconf.serial = htonl(serial);
2860 
2861 	retval->subh.addip_hdr =
2862 		sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2863 
2864 	return retval;
2865 }
2866 
2867 /* Add response parameters to an ASCONF_ACK chunk. */
2868 static void sctp_add_asconf_response(struct sctp_chunk *chunk, __be32 crr_id,
2869 			      __be16 err_code, sctp_addip_param_t *asconf_param)
2870 {
2871 	sctp_addip_param_t 	ack_param;
2872 	sctp_errhdr_t		err_param;
2873 	int			asconf_param_len = 0;
2874 	int			err_param_len = 0;
2875 	__be16			response_type;
2876 
2877 	if (SCTP_ERROR_NO_ERROR == err_code) {
2878 		response_type = SCTP_PARAM_SUCCESS_REPORT;
2879 	} else {
2880 		response_type = SCTP_PARAM_ERR_CAUSE;
2881 		err_param_len = sizeof(err_param);
2882 		if (asconf_param)
2883 			asconf_param_len =
2884 				 ntohs(asconf_param->param_hdr.length);
2885 	}
2886 
2887 	/* Add Success Indication or Error Cause Indication parameter. */
2888 	ack_param.param_hdr.type = response_type;
2889 	ack_param.param_hdr.length = htons(sizeof(ack_param) +
2890 					   err_param_len +
2891 					   asconf_param_len);
2892 	ack_param.crr_id = crr_id;
2893 	sctp_addto_chunk(chunk, sizeof(ack_param), &ack_param);
2894 
2895 	if (SCTP_ERROR_NO_ERROR == err_code)
2896 		return;
2897 
2898 	/* Add Error Cause parameter. */
2899 	err_param.cause = err_code;
2900 	err_param.length = htons(err_param_len + asconf_param_len);
2901 	sctp_addto_chunk(chunk, err_param_len, &err_param);
2902 
2903 	/* Add the failed TLV copied from ASCONF chunk. */
2904 	if (asconf_param)
2905 		sctp_addto_chunk(chunk, asconf_param_len, asconf_param);
2906 }
2907 
2908 /* Process a asconf parameter. */
2909 static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
2910 				       struct sctp_chunk *asconf,
2911 				       sctp_addip_param_t *asconf_param)
2912 {
2913 	struct sctp_transport *peer;
2914 	struct sctp_af *af;
2915 	union sctp_addr	addr;
2916 	union sctp_addr_param *addr_param;
2917 
2918 	addr_param = (union sctp_addr_param *)
2919 			((void *)asconf_param + sizeof(sctp_addip_param_t));
2920 
2921 	if (asconf_param->param_hdr.type != SCTP_PARAM_ADD_IP &&
2922 	    asconf_param->param_hdr.type != SCTP_PARAM_DEL_IP &&
2923 	    asconf_param->param_hdr.type != SCTP_PARAM_SET_PRIMARY)
2924 		return SCTP_ERROR_UNKNOWN_PARAM;
2925 
2926 	switch (addr_param->v4.param_hdr.type) {
2927 	case SCTP_PARAM_IPV6_ADDRESS:
2928 		if (!asoc->peer.ipv6_address)
2929 			return SCTP_ERROR_DNS_FAILED;
2930 		break;
2931 	case SCTP_PARAM_IPV4_ADDRESS:
2932 		if (!asoc->peer.ipv4_address)
2933 			return SCTP_ERROR_DNS_FAILED;
2934 		break;
2935 	default:
2936 		return SCTP_ERROR_DNS_FAILED;
2937 	}
2938 
2939 	af = sctp_get_af_specific(param_type2af(addr_param->v4.param_hdr.type));
2940 	if (unlikely(!af))
2941 		return SCTP_ERROR_DNS_FAILED;
2942 
2943 	af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);
2944 
2945 	/* ADDIP 4.2.1  This parameter MUST NOT contain a broadcast
2946 	 * or multicast address.
2947 	 * (note: wildcard is permitted and requires special handling so
2948 	 *  make sure we check for that)
2949 	 */
2950 	if (!af->is_any(&addr) && !af->addr_valid(&addr, NULL, asconf->skb))
2951 		return SCTP_ERROR_DNS_FAILED;
2952 
2953 	switch (asconf_param->param_hdr.type) {
2954 	case SCTP_PARAM_ADD_IP:
2955 		/* Section 4.2.1:
2956 		 * If the address 0.0.0.0 or ::0 is provided, the source
2957 		 * address of the packet MUST be added.
2958 		 */
2959 		if (af->is_any(&addr))
2960 			memcpy(&addr, &asconf->source, sizeof(addr));
2961 
2962 		/* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
2963 		 * request and does not have the local resources to add this
2964 		 * new address to the association, it MUST return an Error
2965 		 * Cause TLV set to the new error code 'Operation Refused
2966 		 * Due to Resource Shortage'.
2967 		 */
2968 
2969 		peer = sctp_assoc_add_peer(asoc, &addr, GFP_ATOMIC, SCTP_UNCONFIRMED);
2970 		if (!peer)
2971 			return SCTP_ERROR_RSRC_LOW;
2972 
2973 		/* Start the heartbeat timer. */
2974 		if (!mod_timer(&peer->hb_timer, sctp_transport_timeout(peer)))
2975 			sctp_transport_hold(peer);
2976 		break;
2977 	case SCTP_PARAM_DEL_IP:
2978 		/* ADDIP 4.3 D7) If a request is received to delete the
2979 		 * last remaining IP address of a peer endpoint, the receiver
2980 		 * MUST send an Error Cause TLV with the error cause set to the
2981 		 * new error code 'Request to Delete Last Remaining IP Address'.
2982 		 */
2983 		if (asoc->peer.transport_count == 1)
2984 			return SCTP_ERROR_DEL_LAST_IP;
2985 
2986 		/* ADDIP 4.3 D8) If a request is received to delete an IP
2987 		 * address which is also the source address of the IP packet
2988 		 * which contained the ASCONF chunk, the receiver MUST reject
2989 		 * this request. To reject the request the receiver MUST send
2990 		 * an Error Cause TLV set to the new error code 'Request to
2991 		 * Delete Source IP Address'
2992 		 */
2993 		if (sctp_cmp_addr_exact(sctp_source(asconf), &addr))
2994 			return SCTP_ERROR_DEL_SRC_IP;
2995 
2996 		/* Section 4.2.2
2997 		 * If the address 0.0.0.0 or ::0 is provided, all
2998 		 * addresses of the peer except	the source address of the
2999 		 * packet MUST be deleted.
3000 		 */
3001 		if (af->is_any(&addr)) {
3002 			sctp_assoc_set_primary(asoc, asconf->transport);
3003 			sctp_assoc_del_nonprimary_peers(asoc,
3004 							asconf->transport);
3005 		} else
3006 			sctp_assoc_del_peer(asoc, &addr);
3007 		break;
3008 	case SCTP_PARAM_SET_PRIMARY:
3009 		/* ADDIP Section 4.2.4
3010 		 * If the address 0.0.0.0 or ::0 is provided, the receiver
3011 		 * MAY mark the source address of the packet as its
3012 		 * primary.
3013 		 */
3014 		if (af->is_any(&addr))
3015 			memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));
3016 
3017 		peer = sctp_assoc_lookup_paddr(asoc, &addr);
3018 		if (!peer)
3019 			return SCTP_ERROR_DNS_FAILED;
3020 
3021 		sctp_assoc_set_primary(asoc, peer);
3022 		break;
3023 	}
3024 
3025 	return SCTP_ERROR_NO_ERROR;
3026 }
3027 
3028 /* Verify the ASCONF packet before we process it.  */
3029 int sctp_verify_asconf(const struct sctp_association *asoc,
3030 		       struct sctp_paramhdr *param_hdr, void *chunk_end,
3031 		       struct sctp_paramhdr **errp) {
3032 	sctp_addip_param_t *asconf_param;
3033 	union sctp_params param;
3034 	int length, plen;
3035 
3036 	param.v = (sctp_paramhdr_t *) param_hdr;
3037 	while (param.v <= chunk_end - sizeof(sctp_paramhdr_t)) {
3038 		length = ntohs(param.p->length);
3039 		*errp = param.p;
3040 
3041 		if (param.v > chunk_end - length ||
3042 		    length < sizeof(sctp_paramhdr_t))
3043 			return 0;
3044 
3045 		switch (param.p->type) {
3046 		case SCTP_PARAM_ADD_IP:
3047 		case SCTP_PARAM_DEL_IP:
3048 		case SCTP_PARAM_SET_PRIMARY:
3049 			asconf_param = (sctp_addip_param_t *)param.v;
3050 			plen = ntohs(asconf_param->param_hdr.length);
3051 			if (plen < sizeof(sctp_addip_param_t) +
3052 			    sizeof(sctp_paramhdr_t))
3053 				return 0;
3054 			break;
3055 		case SCTP_PARAM_SUCCESS_REPORT:
3056 		case SCTP_PARAM_ADAPTATION_LAYER_IND:
3057 			if (length != sizeof(sctp_addip_param_t))
3058 				return 0;
3059 
3060 			break;
3061 		default:
3062 			break;
3063 		}
3064 
3065 		param.v += WORD_ROUND(length);
3066 	}
3067 
3068 	if (param.v != chunk_end)
3069 		return 0;
3070 
3071 	return 1;
3072 }
3073 
3074 /* Process an incoming ASCONF chunk with the next expected serial no. and
3075  * return an ASCONF_ACK chunk to be sent in response.
3076  */
3077 struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
3078 				       struct sctp_chunk *asconf)
3079 {
3080 	sctp_addiphdr_t		*hdr;
3081 	union sctp_addr_param	*addr_param;
3082 	sctp_addip_param_t	*asconf_param;
3083 	struct sctp_chunk	*asconf_ack;
3084 
3085 	__be16	err_code;
3086 	int	length = 0;
3087 	int	chunk_len;
3088 	__u32	serial;
3089 	int	all_param_pass = 1;
3090 
3091 	chunk_len = ntohs(asconf->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
3092 	hdr = (sctp_addiphdr_t *)asconf->skb->data;
3093 	serial = ntohl(hdr->serial);
3094 
3095 	/* Skip the addiphdr and store a pointer to address parameter.  */
3096 	length = sizeof(sctp_addiphdr_t);
3097 	addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3098 	chunk_len -= length;
3099 
3100 	/* Skip the address parameter and store a pointer to the first
3101 	 * asconf parameter.
3102 	 */
3103 	length = ntohs(addr_param->v4.param_hdr.length);
3104 	asconf_param = (sctp_addip_param_t *)((void *)addr_param + length);
3105 	chunk_len -= length;
3106 
3107 	/* create an ASCONF_ACK chunk.
3108 	 * Based on the definitions of parameters, we know that the size of
3109 	 * ASCONF_ACK parameters are less than or equal to the twice of ASCONF
3110 	 * parameters.
3111 	 */
3112 	asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 2);
3113 	if (!asconf_ack)
3114 		goto done;
3115 
3116 	/* Process the TLVs contained within the ASCONF chunk. */
3117 	while (chunk_len > 0) {
3118 		err_code = sctp_process_asconf_param(asoc, asconf,
3119 						     asconf_param);
3120 		/* ADDIP 4.1 A7)
3121 		 * If an error response is received for a TLV parameter,
3122 		 * all TLVs with no response before the failed TLV are
3123 		 * considered successful if not reported.  All TLVs after
3124 		 * the failed response are considered unsuccessful unless
3125 		 * a specific success indication is present for the parameter.
3126 		 */
3127 		if (SCTP_ERROR_NO_ERROR != err_code)
3128 			all_param_pass = 0;
3129 
3130 		if (!all_param_pass)
3131 			sctp_add_asconf_response(asconf_ack,
3132 						 asconf_param->crr_id, err_code,
3133 						 asconf_param);
3134 
3135 		/* ADDIP 4.3 D11) When an endpoint receiving an ASCONF to add
3136 		 * an IP address sends an 'Out of Resource' in its response, it
3137 		 * MUST also fail any subsequent add or delete requests bundled
3138 		 * in the ASCONF.
3139 		 */
3140 		if (SCTP_ERROR_RSRC_LOW == err_code)
3141 			goto done;
3142 
3143 		/* Move to the next ASCONF param. */
3144 		length = ntohs(asconf_param->param_hdr.length);
3145 		asconf_param = (sctp_addip_param_t *)((void *)asconf_param +
3146 						      length);
3147 		chunk_len -= length;
3148 	}
3149 
3150 done:
3151 	asoc->peer.addip_serial++;
3152 
3153 	/* If we are sending a new ASCONF_ACK hold a reference to it in assoc
3154 	 * after freeing the reference to old asconf ack if any.
3155 	 */
3156 	if (asconf_ack) {
3157 		sctp_chunk_hold(asconf_ack);
3158 		list_add_tail(&asconf_ack->transmitted_list,
3159 			      &asoc->asconf_ack_list);
3160 	}
3161 
3162 	return asconf_ack;
3163 }
3164 
3165 /* Process a asconf parameter that is successfully acked. */
3166 static void sctp_asconf_param_success(struct sctp_association *asoc,
3167 				     sctp_addip_param_t *asconf_param)
3168 {
3169 	struct sctp_af *af;
3170 	union sctp_addr	addr;
3171 	struct sctp_bind_addr *bp = &asoc->base.bind_addr;
3172 	union sctp_addr_param *addr_param;
3173 	struct sctp_transport *transport;
3174 	struct sctp_sockaddr_entry *saddr;
3175 
3176 	addr_param = (union sctp_addr_param *)
3177 			((void *)asconf_param + sizeof(sctp_addip_param_t));
3178 
3179 	/* We have checked the packet before, so we do not check again.	*/
3180 	af = sctp_get_af_specific(param_type2af(addr_param->v4.param_hdr.type));
3181 	af->from_addr_param(&addr, addr_param, htons(bp->port), 0);
3182 
3183 	switch (asconf_param->param_hdr.type) {
3184 	case SCTP_PARAM_ADD_IP:
3185 		/* This is always done in BH context with a socket lock
3186 		 * held, so the list can not change.
3187 		 */
3188 		local_bh_disable();
3189 		list_for_each_entry(saddr, &bp->address_list, list) {
3190 			if (sctp_cmp_addr_exact(&saddr->a, &addr))
3191 				saddr->state = SCTP_ADDR_SRC;
3192 		}
3193 		local_bh_enable();
3194 		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3195 				transports) {
3196 			if (transport->state == SCTP_ACTIVE)
3197 				continue;
3198 			dst_release(transport->dst);
3199 			sctp_transport_route(transport, NULL,
3200 					     sctp_sk(asoc->base.sk));
3201 		}
3202 		break;
3203 	case SCTP_PARAM_DEL_IP:
3204 		local_bh_disable();
3205 		sctp_del_bind_addr(bp, &addr);
3206 		local_bh_enable();
3207 		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3208 				transports) {
3209 			dst_release(transport->dst);
3210 			sctp_transport_route(transport, NULL,
3211 					     sctp_sk(asoc->base.sk));
3212 		}
3213 		break;
3214 	default:
3215 		break;
3216 	}
3217 }
3218 
3219 /* Get the corresponding ASCONF response error code from the ASCONF_ACK chunk
3220  * for the given asconf parameter.  If there is no response for this parameter,
3221  * return the error code based on the third argument 'no_err'.
3222  * ADDIP 4.1
3223  * A7) If an error response is received for a TLV parameter, all TLVs with no
3224  * response before the failed TLV are considered successful if not reported.
3225  * All TLVs after the failed response are considered unsuccessful unless a
3226  * specific success indication is present for the parameter.
3227  */
3228 static __be16 sctp_get_asconf_response(struct sctp_chunk *asconf_ack,
3229 				      sctp_addip_param_t *asconf_param,
3230 				      int no_err)
3231 {
3232 	sctp_addip_param_t	*asconf_ack_param;
3233 	sctp_errhdr_t		*err_param;
3234 	int			length;
3235 	int			asconf_ack_len;
3236 	__be16			err_code;
3237 
3238 	if (no_err)
3239 		err_code = SCTP_ERROR_NO_ERROR;
3240 	else
3241 		err_code = SCTP_ERROR_REQ_REFUSED;
3242 
3243 	asconf_ack_len = ntohs(asconf_ack->chunk_hdr->length) -
3244 			     sizeof(sctp_chunkhdr_t);
3245 
3246 	/* Skip the addiphdr from the asconf_ack chunk and store a pointer to
3247 	 * the first asconf_ack parameter.
3248 	 */
3249 	length = sizeof(sctp_addiphdr_t);
3250 	asconf_ack_param = (sctp_addip_param_t *)(asconf_ack->skb->data +
3251 						  length);
3252 	asconf_ack_len -= length;
3253 
3254 	while (asconf_ack_len > 0) {
3255 		if (asconf_ack_param->crr_id == asconf_param->crr_id) {
3256 			switch(asconf_ack_param->param_hdr.type) {
3257 			case SCTP_PARAM_SUCCESS_REPORT:
3258 				return SCTP_ERROR_NO_ERROR;
3259 			case SCTP_PARAM_ERR_CAUSE:
3260 				length = sizeof(sctp_addip_param_t);
3261 				err_param = (sctp_errhdr_t *)
3262 					   ((void *)asconf_ack_param + length);
3263 				asconf_ack_len -= length;
3264 				if (asconf_ack_len > 0)
3265 					return err_param->cause;
3266 				else
3267 					return SCTP_ERROR_INV_PARAM;
3268 				break;
3269 			default:
3270 				return SCTP_ERROR_INV_PARAM;
3271 			}
3272 		}
3273 
3274 		length = ntohs(asconf_ack_param->param_hdr.length);
3275 		asconf_ack_param = (sctp_addip_param_t *)
3276 					((void *)asconf_ack_param + length);
3277 		asconf_ack_len -= length;
3278 	}
3279 
3280 	return err_code;
3281 }
3282 
3283 /* Process an incoming ASCONF_ACK chunk against the cached last ASCONF chunk. */
3284 int sctp_process_asconf_ack(struct sctp_association *asoc,
3285 			    struct sctp_chunk *asconf_ack)
3286 {
3287 	struct sctp_chunk	*asconf = asoc->addip_last_asconf;
3288 	union sctp_addr_param	*addr_param;
3289 	sctp_addip_param_t	*asconf_param;
3290 	int	length = 0;
3291 	int	asconf_len = asconf->skb->len;
3292 	int	all_param_pass = 0;
3293 	int	no_err = 1;
3294 	int	retval = 0;
3295 	__be16	err_code = SCTP_ERROR_NO_ERROR;
3296 
3297 	/* Skip the chunkhdr and addiphdr from the last asconf sent and store
3298 	 * a pointer to address parameter.
3299 	 */
3300 	length = sizeof(sctp_addip_chunk_t);
3301 	addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3302 	asconf_len -= length;
3303 
3304 	/* Skip the address parameter in the last asconf sent and store a
3305 	 * pointer to the first asconf parameter.
3306 	 */
3307 	length = ntohs(addr_param->v4.param_hdr.length);
3308 	asconf_param = (sctp_addip_param_t *)((void *)addr_param + length);
3309 	asconf_len -= length;
3310 
3311 	/* ADDIP 4.1
3312 	 * A8) If there is no response(s) to specific TLV parameter(s), and no
3313 	 * failures are indicated, then all request(s) are considered
3314 	 * successful.
3315 	 */
3316 	if (asconf_ack->skb->len == sizeof(sctp_addiphdr_t))
3317 		all_param_pass = 1;
3318 
3319 	/* Process the TLVs contained in the last sent ASCONF chunk. */
3320 	while (asconf_len > 0) {
3321 		if (all_param_pass)
3322 			err_code = SCTP_ERROR_NO_ERROR;
3323 		else {
3324 			err_code = sctp_get_asconf_response(asconf_ack,
3325 							    asconf_param,
3326 							    no_err);
3327 			if (no_err && (SCTP_ERROR_NO_ERROR != err_code))
3328 				no_err = 0;
3329 		}
3330 
3331 		switch (err_code) {
3332 		case SCTP_ERROR_NO_ERROR:
3333 			sctp_asconf_param_success(asoc, asconf_param);
3334 			break;
3335 
3336 		case SCTP_ERROR_RSRC_LOW:
3337 			retval = 1;
3338 			break;
3339 
3340 		case SCTP_ERROR_UNKNOWN_PARAM:
3341 			/* Disable sending this type of asconf parameter in
3342 			 * future.
3343 			 */
3344 			asoc->peer.addip_disabled_mask |=
3345 				asconf_param->param_hdr.type;
3346 			break;
3347 
3348 		case SCTP_ERROR_REQ_REFUSED:
3349 		case SCTP_ERROR_DEL_LAST_IP:
3350 		case SCTP_ERROR_DEL_SRC_IP:
3351 		default:
3352 			 break;
3353 		}
3354 
3355 		/* Skip the processed asconf parameter and move to the next
3356 		 * one.
3357 		 */
3358 		length = ntohs(asconf_param->param_hdr.length);
3359 		asconf_param = (sctp_addip_param_t *)((void *)asconf_param +
3360 						      length);
3361 		asconf_len -= length;
3362 	}
3363 
3364 	/* Free the cached last sent asconf chunk. */
3365 	list_del_init(&asconf->transmitted_list);
3366 	sctp_chunk_free(asconf);
3367 	asoc->addip_last_asconf = NULL;
3368 
3369 	return retval;
3370 }
3371 
3372 /* Make a FWD TSN chunk. */
3373 struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
3374 				    __u32 new_cum_tsn, size_t nstreams,
3375 				    struct sctp_fwdtsn_skip *skiplist)
3376 {
3377 	struct sctp_chunk *retval = NULL;
3378 	struct sctp_fwdtsn_chunk *ftsn_chunk;
3379 	struct sctp_fwdtsn_hdr ftsn_hdr;
3380 	struct sctp_fwdtsn_skip skip;
3381 	size_t hint;
3382 	int i;
3383 
3384 	hint = (nstreams + 1) * sizeof(__u32);
3385 
3386 	retval = sctp_make_chunk(asoc, SCTP_CID_FWD_TSN, 0, hint);
3387 
3388 	if (!retval)
3389 		return NULL;
3390 
3391 	ftsn_chunk = (struct sctp_fwdtsn_chunk *)retval->subh.fwdtsn_hdr;
3392 
3393 	ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
3394 	retval->subh.fwdtsn_hdr =
3395 		sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
3396 
3397 	for (i = 0; i < nstreams; i++) {
3398 		skip.stream = skiplist[i].stream;
3399 		skip.ssn = skiplist[i].ssn;
3400 		sctp_addto_chunk(retval, sizeof(skip), &skip);
3401 	}
3402 
3403 	return retval;
3404 }
3405