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? */
sctp_chunk_iif(const struct sctp_chunk * 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  */
sctp_init_cause(struct sctp_chunk * chunk,__be16 cause_code,size_t paylen)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  */
sctp_init_cause_fixed(struct sctp_chunk * chunk,__be16 cause_code,size_t paylen)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  */
sctp_make_init(const struct sctp_association * asoc,const struct sctp_bind_addr * bp,gfp_t gfp,int vparam_len)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 
sctp_make_init_ack(const struct sctp_association * asoc,const struct sctp_chunk * chunk,gfp_t gfp,int unkparam_len)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  */
sctp_make_cookie_echo(const struct sctp_association * asoc,const struct sctp_chunk * chunk)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  */
sctp_make_cookie_ack(const struct sctp_association * asoc,const struct sctp_chunk * chunk)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  */
sctp_make_cwr(const struct sctp_association * asoc,const __u32 lowest_tsn,const struct sctp_chunk * chunk)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.  */
sctp_make_ecne(const struct sctp_association * asoc,const __u32 lowest_tsn)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  */
sctp_make_datafrag_empty(struct sctp_association * asoc,const struct sctp_sndrcvinfo * sinfo,int data_len,__u8 flags,__u16 ssn)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  */
sctp_make_sack(const struct sctp_association * asoc)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. */
sctp_make_shutdown(const struct sctp_association * asoc,const struct sctp_chunk * 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 
sctp_make_shutdown_ack(const struct sctp_association * asoc,const struct sctp_chunk * chunk)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 
sctp_make_shutdown_complete(const struct sctp_association * asoc,const struct sctp_chunk * chunk)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  */
sctp_make_abort(const struct sctp_association * asoc,const struct sctp_chunk * chunk,const size_t hint)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.  */
sctp_make_abort_no_data(const struct sctp_association * asoc,const struct sctp_chunk * chunk,__u32 tsn)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.  */
sctp_make_abort_user(const struct sctp_association * asoc,const struct msghdr * msg,size_t paylen)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  */
sctp_addto_param(struct sctp_chunk * chunk,int len,const void * data)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. */
sctp_make_abort_violation(const struct sctp_association * asoc,const struct sctp_chunk * chunk,const __u8 * payload,const size_t paylen)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 
sctp_make_violation_paramlen(const struct sctp_association * asoc,const struct sctp_chunk * chunk,struct sctp_paramhdr * param)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.  */
sctp_make_heartbeat(const struct sctp_association * asoc,const struct sctp_transport * transport)1077 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
1078 				  const struct sctp_transport *transport)
1079 {
1080 	struct sctp_chunk *retval;
1081 	sctp_sender_hb_info_t hbinfo;
1082 
1083 	retval = sctp_make_chunk(asoc, SCTP_CID_HEARTBEAT, 0, sizeof(hbinfo));
1084 
1085 	if (!retval)
1086 		goto nodata;
1087 
1088 	hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO;
1089 	hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t));
1090 	hbinfo.daddr = transport->ipaddr;
1091 	hbinfo.sent_at = jiffies;
1092 	hbinfo.hb_nonce = transport->hb_nonce;
1093 
1094 	/* Cast away the 'const', as this is just telling the chunk
1095 	 * what transport it belongs to.
1096 	 */
1097 	retval->transport = (struct sctp_transport *) transport;
1098 	retval->subh.hbs_hdr = sctp_addto_chunk(retval, sizeof(hbinfo),
1099 						&hbinfo);
1100 
1101 nodata:
1102 	return retval;
1103 }
1104 
sctp_make_heartbeat_ack(const struct sctp_association * asoc,const struct sctp_chunk * chunk,const void * payload,const size_t paylen)1105 struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc,
1106 				      const struct sctp_chunk *chunk,
1107 				      const void *payload, const size_t paylen)
1108 {
1109 	struct sctp_chunk *retval;
1110 
1111 	retval  = sctp_make_chunk(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen);
1112 	if (!retval)
1113 		goto nodata;
1114 
1115 	retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);
1116 
1117 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
1118 	 *
1119 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1120 	 * HEARTBEAT ACK, * etc.) to the same destination transport
1121 	 * address from which it * received the DATA or control chunk
1122 	 * to which it is replying.
1123 	 *
1124 	 * [HBACK back to where the HEARTBEAT came from.]
1125 	 */
1126 	if (chunk)
1127 		retval->transport = chunk->transport;
1128 
1129 nodata:
1130 	return retval;
1131 }
1132 
1133 /* Create an Operation Error chunk with the specified space reserved.
1134  * This routine can be used for containing multiple causes in the chunk.
1135  */
sctp_make_op_error_space(const struct sctp_association * asoc,const struct sctp_chunk * chunk,size_t size)1136 static struct sctp_chunk *sctp_make_op_error_space(
1137 	const struct sctp_association *asoc,
1138 	const struct sctp_chunk *chunk,
1139 	size_t size)
1140 {
1141 	struct sctp_chunk *retval;
1142 
1143 	retval = sctp_make_chunk(asoc, SCTP_CID_ERROR, 0,
1144 				 sizeof(sctp_errhdr_t) + size);
1145 	if (!retval)
1146 		goto nodata;
1147 
1148 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
1149 	 *
1150 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1151 	 * HEARTBEAT ACK, etc.) to the same destination transport
1152 	 * address from which it received the DATA or control chunk
1153 	 * to which it is replying.
1154 	 *
1155 	 */
1156 	if (chunk)
1157 		retval->transport = chunk->transport;
1158 
1159 nodata:
1160 	return retval;
1161 }
1162 
1163 /* Create an Operation Error chunk of a fixed size,
1164  * specifically, max(asoc->pathmtu, SCTP_DEFAULT_MAXSEGMENT)
1165  * This is a helper function to allocate an error chunk for
1166  * for those invalid parameter codes in which we may not want
1167  * to report all the errors, if the incomming chunk is large
1168  */
sctp_make_op_error_fixed(const struct sctp_association * asoc,const struct sctp_chunk * chunk)1169 static inline struct sctp_chunk *sctp_make_op_error_fixed(
1170 	const struct sctp_association *asoc,
1171 	const struct sctp_chunk *chunk)
1172 {
1173 	size_t size = asoc ? asoc->pathmtu : 0;
1174 
1175 	if (!size)
1176 		size = SCTP_DEFAULT_MAXSEGMENT;
1177 
1178 	return sctp_make_op_error_space(asoc, chunk, size);
1179 }
1180 
1181 /* Create an Operation Error chunk.  */
sctp_make_op_error(const struct sctp_association * asoc,const struct sctp_chunk * chunk,__be16 cause_code,const void * payload,size_t paylen,size_t reserve_tail)1182 struct sctp_chunk *sctp_make_op_error(const struct sctp_association *asoc,
1183 				 const struct sctp_chunk *chunk,
1184 				 __be16 cause_code, const void *payload,
1185 				 size_t paylen, size_t reserve_tail)
1186 {
1187 	struct sctp_chunk *retval;
1188 
1189 	retval = sctp_make_op_error_space(asoc, chunk, paylen + reserve_tail);
1190 	if (!retval)
1191 		goto nodata;
1192 
1193 	sctp_init_cause(retval, cause_code, paylen + reserve_tail);
1194 	sctp_addto_chunk(retval, paylen, payload);
1195 	if (reserve_tail)
1196 		sctp_addto_param(retval, reserve_tail, NULL);
1197 
1198 nodata:
1199 	return retval;
1200 }
1201 
sctp_make_auth(const struct sctp_association * asoc)1202 struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc)
1203 {
1204 	struct sctp_chunk *retval;
1205 	struct sctp_hmac *hmac_desc;
1206 	struct sctp_authhdr auth_hdr;
1207 	__u8 *hmac;
1208 
1209 	/* Get the first hmac that the peer told us to use */
1210 	hmac_desc = sctp_auth_asoc_get_hmac(asoc);
1211 	if (unlikely(!hmac_desc))
1212 		return NULL;
1213 
1214 	retval = sctp_make_chunk(asoc, SCTP_CID_AUTH, 0,
1215 			hmac_desc->hmac_len + sizeof(sctp_authhdr_t));
1216 	if (!retval)
1217 		return NULL;
1218 
1219 	auth_hdr.hmac_id = htons(hmac_desc->hmac_id);
1220 	auth_hdr.shkey_id = htons(asoc->active_key_id);
1221 
1222 	retval->subh.auth_hdr = sctp_addto_chunk(retval, sizeof(sctp_authhdr_t),
1223 						&auth_hdr);
1224 
1225 	hmac = skb_put(retval->skb, hmac_desc->hmac_len);
1226 	memset(hmac, 0, hmac_desc->hmac_len);
1227 
1228 	/* Adjust the chunk header to include the empty MAC */
1229 	retval->chunk_hdr->length =
1230 		htons(ntohs(retval->chunk_hdr->length) + hmac_desc->hmac_len);
1231 	retval->chunk_end = skb_tail_pointer(retval->skb);
1232 
1233 	return retval;
1234 }
1235 
1236 
1237 /********************************************************************
1238  * 2nd Level Abstractions
1239  ********************************************************************/
1240 
1241 /* Turn an skb into a chunk.
1242  * FIXME: Eventually move the structure directly inside the skb->cb[].
1243  */
sctp_chunkify(struct sk_buff * skb,const struct sctp_association * asoc,struct sock * sk)1244 struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
1245 			    const struct sctp_association *asoc,
1246 			    struct sock *sk)
1247 {
1248 	struct sctp_chunk *retval;
1249 
1250 	retval = kmem_cache_zalloc(sctp_chunk_cachep, GFP_ATOMIC);
1251 
1252 	if (!retval)
1253 		goto nodata;
1254 
1255 	if (!sk) {
1256 		SCTP_DEBUG_PRINTK("chunkifying skb %p w/o an sk\n", skb);
1257 	}
1258 
1259 	INIT_LIST_HEAD(&retval->list);
1260 	retval->skb		= skb;
1261 	retval->asoc		= (struct sctp_association *)asoc;
1262 	retval->has_tsn		= 0;
1263 	retval->has_ssn         = 0;
1264 	retval->rtt_in_progress	= 0;
1265 	retval->sent_at		= 0;
1266 	retval->singleton	= 1;
1267 	retval->end_of_packet	= 0;
1268 	retval->ecn_ce_done	= 0;
1269 	retval->pdiscard	= 0;
1270 
1271 	/* sctpimpguide-05.txt Section 2.8.2
1272 	 * M1) Each time a new DATA chunk is transmitted
1273 	 * set the 'TSN.Missing.Report' count for that TSN to 0. The
1274 	 * 'TSN.Missing.Report' count will be used to determine missing chunks
1275 	 * and when to fast retransmit.
1276 	 */
1277 	retval->tsn_missing_report = 0;
1278 	retval->tsn_gap_acked = 0;
1279 	retval->fast_retransmit = SCTP_CAN_FRTX;
1280 
1281 	/* If this is a fragmented message, track all fragments
1282 	 * of the message (for SEND_FAILED).
1283 	 */
1284 	retval->msg = NULL;
1285 
1286 	/* Polish the bead hole.  */
1287 	INIT_LIST_HEAD(&retval->transmitted_list);
1288 	INIT_LIST_HEAD(&retval->frag_list);
1289 	SCTP_DBG_OBJCNT_INC(chunk);
1290 	atomic_set(&retval->refcnt, 1);
1291 
1292 nodata:
1293 	return retval;
1294 }
1295 
1296 /* Set chunk->source and dest based on the IP header in chunk->skb.  */
sctp_init_addrs(struct sctp_chunk * chunk,union sctp_addr * src,union sctp_addr * dest)1297 void sctp_init_addrs(struct sctp_chunk *chunk, union sctp_addr *src,
1298 		     union sctp_addr *dest)
1299 {
1300 	memcpy(&chunk->source, src, sizeof(union sctp_addr));
1301 	memcpy(&chunk->dest, dest, sizeof(union sctp_addr));
1302 }
1303 
1304 /* Extract the source address from a chunk.  */
sctp_source(const struct sctp_chunk * chunk)1305 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk)
1306 {
1307 	/* If we have a known transport, use that.  */
1308 	if (chunk->transport) {
1309 		return &chunk->transport->ipaddr;
1310 	} else {
1311 		/* Otherwise, extract it from the IP header.  */
1312 		return &chunk->source;
1313 	}
1314 }
1315 
1316 /* Create a new chunk, setting the type and flags headers from the
1317  * arguments, reserving enough space for a 'paylen' byte payload.
1318  */
1319 SCTP_STATIC
sctp_make_chunk(const struct sctp_association * asoc,__u8 type,__u8 flags,int paylen)1320 struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc,
1321 				   __u8 type, __u8 flags, int paylen)
1322 {
1323 	struct sctp_chunk *retval;
1324 	sctp_chunkhdr_t *chunk_hdr;
1325 	struct sk_buff *skb;
1326 	struct sock *sk;
1327 
1328 	/* No need to allocate LL here, as this is only a chunk. */
1329 	skb = alloc_skb(WORD_ROUND(sizeof(sctp_chunkhdr_t) + paylen),
1330 			GFP_ATOMIC);
1331 	if (!skb)
1332 		goto nodata;
1333 
1334 	/* Make room for the chunk header.  */
1335 	chunk_hdr = (sctp_chunkhdr_t *)skb_put(skb, sizeof(sctp_chunkhdr_t));
1336 	chunk_hdr->type	  = type;
1337 	chunk_hdr->flags  = flags;
1338 	chunk_hdr->length = htons(sizeof(sctp_chunkhdr_t));
1339 
1340 	sk = asoc ? asoc->base.sk : NULL;
1341 	retval = sctp_chunkify(skb, asoc, sk);
1342 	if (!retval) {
1343 		kfree_skb(skb);
1344 		goto nodata;
1345 	}
1346 
1347 	retval->chunk_hdr = chunk_hdr;
1348 	retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(struct sctp_chunkhdr);
1349 
1350 	/* Determine if the chunk needs to be authenticated */
1351 	if (sctp_auth_send_cid(type, asoc))
1352 		retval->auth = 1;
1353 
1354 	/* Set the skb to the belonging sock for accounting.  */
1355 	skb->sk = sk;
1356 
1357 	return retval;
1358 nodata:
1359 	return NULL;
1360 }
1361 
1362 
1363 /* Release the memory occupied by a chunk.  */
sctp_chunk_destroy(struct sctp_chunk * chunk)1364 static void sctp_chunk_destroy(struct sctp_chunk *chunk)
1365 {
1366 	BUG_ON(!list_empty(&chunk->list));
1367 	list_del_init(&chunk->transmitted_list);
1368 
1369 	consume_skb(chunk->skb);
1370 	consume_skb(chunk->auth_chunk);
1371 
1372 	SCTP_DBG_OBJCNT_DEC(chunk);
1373 	kmem_cache_free(sctp_chunk_cachep, chunk);
1374 }
1375 
1376 /* Possibly, free the chunk.  */
sctp_chunk_free(struct sctp_chunk * chunk)1377 void sctp_chunk_free(struct sctp_chunk *chunk)
1378 {
1379 	/* Release our reference on the message tracker. */
1380 	if (chunk->msg)
1381 		sctp_datamsg_put(chunk->msg);
1382 
1383 	sctp_chunk_put(chunk);
1384 }
1385 
1386 /* Grab a reference to the chunk. */
sctp_chunk_hold(struct sctp_chunk * ch)1387 void sctp_chunk_hold(struct sctp_chunk *ch)
1388 {
1389 	atomic_inc(&ch->refcnt);
1390 }
1391 
1392 /* Release a reference to the chunk. */
sctp_chunk_put(struct sctp_chunk * ch)1393 void sctp_chunk_put(struct sctp_chunk *ch)
1394 {
1395 	if (atomic_dec_and_test(&ch->refcnt))
1396 		sctp_chunk_destroy(ch);
1397 }
1398 
1399 /* Append bytes to the end of a chunk.  Will panic if chunk is not big
1400  * enough.
1401  */
sctp_addto_chunk(struct sctp_chunk * chunk,int len,const void * data)1402 void *sctp_addto_chunk(struct sctp_chunk *chunk, int len, const void *data)
1403 {
1404 	void *target;
1405 	void *padding;
1406 	int chunklen = ntohs(chunk->chunk_hdr->length);
1407 	int padlen = WORD_ROUND(chunklen) - chunklen;
1408 
1409 	padding = skb_put(chunk->skb, padlen);
1410 	target = skb_put(chunk->skb, len);
1411 
1412 	memset(padding, 0, padlen);
1413 	memcpy(target, data, len);
1414 
1415 	/* Adjust the chunk length field.  */
1416 	chunk->chunk_hdr->length = htons(chunklen + padlen + len);
1417 	chunk->chunk_end = skb_tail_pointer(chunk->skb);
1418 
1419 	return target;
1420 }
1421 
1422 /* Append bytes to the end of a chunk. Returns NULL if there isn't sufficient
1423  * space in the chunk
1424  */
sctp_addto_chunk_fixed(struct sctp_chunk * chunk,int len,const void * data)1425 void *sctp_addto_chunk_fixed(struct sctp_chunk *chunk,
1426 			     int len, const void *data)
1427 {
1428 	if (skb_tailroom(chunk->skb) >= len)
1429 		return sctp_addto_chunk(chunk, len, data);
1430 	else
1431 		return NULL;
1432 }
1433 
1434 /* Append bytes from user space to the end of a chunk.  Will panic if
1435  * chunk is not big enough.
1436  * Returns a kernel err value.
1437  */
sctp_user_addto_chunk(struct sctp_chunk * chunk,int off,int len,struct iovec * data)1438 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int off, int len,
1439 			  struct iovec *data)
1440 {
1441 	__u8 *target;
1442 	int err = 0;
1443 
1444 	/* Make room in chunk for data.  */
1445 	target = skb_put(chunk->skb, len);
1446 
1447 	/* Copy data (whole iovec) into chunk */
1448 	if ((err = memcpy_fromiovecend(target, data, off, len)))
1449 		goto out;
1450 
1451 	/* Adjust the chunk length field.  */
1452 	chunk->chunk_hdr->length =
1453 		htons(ntohs(chunk->chunk_hdr->length) + len);
1454 	chunk->chunk_end = skb_tail_pointer(chunk->skb);
1455 
1456 out:
1457 	return err;
1458 }
1459 
1460 /* Helper function to assign a TSN if needed.  This assumes that both
1461  * the data_hdr and association have already been assigned.
1462  */
sctp_chunk_assign_ssn(struct sctp_chunk * chunk)1463 void sctp_chunk_assign_ssn(struct sctp_chunk *chunk)
1464 {
1465 	struct sctp_datamsg *msg;
1466 	struct sctp_chunk *lchunk;
1467 	struct sctp_stream *stream;
1468 	__u16 ssn;
1469 	__u16 sid;
1470 
1471 	if (chunk->has_ssn)
1472 		return;
1473 
1474 	/* All fragments will be on the same stream */
1475 	sid = ntohs(chunk->subh.data_hdr->stream);
1476 	stream = &chunk->asoc->ssnmap->out;
1477 
1478 	/* Now assign the sequence number to the entire message.
1479 	 * All fragments must have the same stream sequence number.
1480 	 */
1481 	msg = chunk->msg;
1482 	list_for_each_entry(lchunk, &msg->chunks, frag_list) {
1483 		if (lchunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
1484 			ssn = 0;
1485 		} else {
1486 			if (lchunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG)
1487 				ssn = sctp_ssn_next(stream, sid);
1488 			else
1489 				ssn = sctp_ssn_peek(stream, sid);
1490 		}
1491 
1492 		lchunk->subh.data_hdr->ssn = htons(ssn);
1493 		lchunk->has_ssn = 1;
1494 	}
1495 }
1496 
1497 /* Helper function to assign a TSN if needed.  This assumes that both
1498  * the data_hdr and association have already been assigned.
1499  */
sctp_chunk_assign_tsn(struct sctp_chunk * chunk)1500 void sctp_chunk_assign_tsn(struct sctp_chunk *chunk)
1501 {
1502 	if (!chunk->has_tsn) {
1503 		/* This is the last possible instant to
1504 		 * assign a TSN.
1505 		 */
1506 		chunk->subh.data_hdr->tsn =
1507 			htonl(sctp_association_get_next_tsn(chunk->asoc));
1508 		chunk->has_tsn = 1;
1509 	}
1510 }
1511 
1512 /* Create a CLOSED association to use with an incoming packet.  */
sctp_make_temp_asoc(const struct sctp_endpoint * ep,struct sctp_chunk * chunk,gfp_t gfp)1513 struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *ep,
1514 					struct sctp_chunk *chunk,
1515 					gfp_t gfp)
1516 {
1517 	struct sctp_association *asoc;
1518 	struct sk_buff *skb;
1519 	sctp_scope_t scope;
1520 	struct sctp_af *af;
1521 
1522 	/* Create the bare association.  */
1523 	scope = sctp_scope(sctp_source(chunk));
1524 	asoc = sctp_association_new(ep, ep->base.sk, scope, gfp);
1525 	if (!asoc)
1526 		goto nodata;
1527 	asoc->temp = 1;
1528 	skb = chunk->skb;
1529 	/* Create an entry for the source address of the packet.  */
1530 	af = sctp_get_af_specific(ipver2af(ip_hdr(skb)->version));
1531 	if (unlikely(!af))
1532 		goto fail;
1533 	af->from_skb(&asoc->c.peer_addr, skb, 1);
1534 nodata:
1535 	return asoc;
1536 
1537 fail:
1538 	sctp_association_free(asoc);
1539 	return NULL;
1540 }
1541 
1542 /* Build a cookie representing asoc.
1543  * This INCLUDES the param header needed to put the cookie in the INIT ACK.
1544  */
sctp_pack_cookie(const struct sctp_endpoint * ep,const struct sctp_association * asoc,const struct sctp_chunk * init_chunk,int * cookie_len,const __u8 * raw_addrs,int addrs_len)1545 static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
1546 				      const struct sctp_association *asoc,
1547 				      const struct sctp_chunk *init_chunk,
1548 				      int *cookie_len,
1549 				      const __u8 *raw_addrs, int addrs_len)
1550 {
1551 	sctp_cookie_param_t *retval;
1552 	struct sctp_signed_cookie *cookie;
1553 	struct scatterlist sg;
1554 	int headersize, bodysize;
1555 	unsigned int keylen;
1556 	char *key;
1557 
1558 	/* Header size is static data prior to the actual cookie, including
1559 	 * any padding.
1560 	 */
1561 	headersize = sizeof(sctp_paramhdr_t) +
1562 		     (sizeof(struct sctp_signed_cookie) -
1563 		      sizeof(struct sctp_cookie));
1564 	bodysize = sizeof(struct sctp_cookie)
1565 		+ ntohs(init_chunk->chunk_hdr->length) + addrs_len;
1566 
1567 	/* Pad out the cookie to a multiple to make the signature
1568 	 * functions simpler to write.
1569 	 */
1570 	if (bodysize % SCTP_COOKIE_MULTIPLE)
1571 		bodysize += SCTP_COOKIE_MULTIPLE
1572 			- (bodysize % SCTP_COOKIE_MULTIPLE);
1573 	*cookie_len = headersize + bodysize;
1574 
1575 	/* Clear this memory since we are sending this data structure
1576 	 * out on the network.
1577 	 */
1578 	retval = kzalloc(*cookie_len, GFP_ATOMIC);
1579 	if (!retval)
1580 		goto nodata;
1581 
1582 	cookie = (struct sctp_signed_cookie *) retval->body;
1583 
1584 	/* Set up the parameter header.  */
1585 	retval->p.type = SCTP_PARAM_STATE_COOKIE;
1586 	retval->p.length = htons(*cookie_len);
1587 
1588 	/* Copy the cookie part of the association itself.  */
1589 	cookie->c = asoc->c;
1590 	/* Save the raw address list length in the cookie. */
1591 	cookie->c.raw_addr_list_len = addrs_len;
1592 
1593 	/* Remember PR-SCTP capability. */
1594 	cookie->c.prsctp_capable = asoc->peer.prsctp_capable;
1595 
1596 	/* Save adaptation indication in the cookie. */
1597 	cookie->c.adaptation_ind = asoc->peer.adaptation_ind;
1598 
1599 	/* Set an expiration time for the cookie.  */
1600 	do_gettimeofday(&cookie->c.expiration);
1601 	TIMEVAL_ADD(asoc->cookie_life, cookie->c.expiration);
1602 
1603 	/* Copy the peer's init packet.  */
1604 	memcpy(&cookie->c.peer_init[0], init_chunk->chunk_hdr,
1605 	       ntohs(init_chunk->chunk_hdr->length));
1606 
1607 	/* Copy the raw local address list of the association. */
1608 	memcpy((__u8 *)&cookie->c.peer_init[0] +
1609 	       ntohs(init_chunk->chunk_hdr->length), raw_addrs, addrs_len);
1610 
1611 	if (sctp_sk(ep->base.sk)->hmac) {
1612 		struct hash_desc desc;
1613 
1614 		/* Sign the message.  */
1615 		sg_init_one(&sg, &cookie->c, bodysize);
1616 		keylen = SCTP_SECRET_SIZE;
1617 		key = (char *)ep->secret_key[ep->current_key];
1618 		desc.tfm = sctp_sk(ep->base.sk)->hmac;
1619 		desc.flags = 0;
1620 
1621 		if (crypto_hash_setkey(desc.tfm, key, keylen) ||
1622 		    crypto_hash_digest(&desc, &sg, bodysize, cookie->signature))
1623 			goto free_cookie;
1624 	}
1625 
1626 	return retval;
1627 
1628 free_cookie:
1629 	kfree(retval);
1630 nodata:
1631 	*cookie_len = 0;
1632 	return NULL;
1633 }
1634 
1635 /* Unpack the cookie from COOKIE ECHO chunk, recreating the association.  */
sctp_unpack_cookie(const struct sctp_endpoint * ep,const struct sctp_association * asoc,struct sctp_chunk * chunk,gfp_t gfp,int * error,struct sctp_chunk ** errp)1636 struct sctp_association *sctp_unpack_cookie(
1637 	const struct sctp_endpoint *ep,
1638 	const struct sctp_association *asoc,
1639 	struct sctp_chunk *chunk, gfp_t gfp,
1640 	int *error, struct sctp_chunk **errp)
1641 {
1642 	struct sctp_association *retval = NULL;
1643 	struct sctp_signed_cookie *cookie;
1644 	struct sctp_cookie *bear_cookie;
1645 	int headersize, bodysize, fixed_size;
1646 	__u8 *digest = ep->digest;
1647 	struct scatterlist sg;
1648 	unsigned int keylen, len;
1649 	char *key;
1650 	sctp_scope_t scope;
1651 	struct sk_buff *skb = chunk->skb;
1652 	struct timeval tv;
1653 	struct hash_desc desc;
1654 
1655 	/* Header size is static data prior to the actual cookie, including
1656 	 * any padding.
1657 	 */
1658 	headersize = sizeof(sctp_chunkhdr_t) +
1659 		     (sizeof(struct sctp_signed_cookie) -
1660 		      sizeof(struct sctp_cookie));
1661 	bodysize = ntohs(chunk->chunk_hdr->length) - headersize;
1662 	fixed_size = headersize + sizeof(struct sctp_cookie);
1663 
1664 	/* Verify that the chunk looks like it even has a cookie.
1665 	 * There must be enough room for our cookie and our peer's
1666 	 * INIT chunk.
1667 	 */
1668 	len = ntohs(chunk->chunk_hdr->length);
1669 	if (len < fixed_size + sizeof(struct sctp_chunkhdr))
1670 		goto malformed;
1671 
1672 	/* Verify that the cookie has been padded out. */
1673 	if (bodysize % SCTP_COOKIE_MULTIPLE)
1674 		goto malformed;
1675 
1676 	/* Process the cookie.  */
1677 	cookie = chunk->subh.cookie_hdr;
1678 	bear_cookie = &cookie->c;
1679 
1680 	if (!sctp_sk(ep->base.sk)->hmac)
1681 		goto no_hmac;
1682 
1683 	/* Check the signature.  */
1684 	keylen = SCTP_SECRET_SIZE;
1685 	sg_init_one(&sg, bear_cookie, bodysize);
1686 	key = (char *)ep->secret_key[ep->current_key];
1687 	desc.tfm = sctp_sk(ep->base.sk)->hmac;
1688 	desc.flags = 0;
1689 
1690 	memset(digest, 0x00, SCTP_SIGNATURE_SIZE);
1691 	if (crypto_hash_setkey(desc.tfm, key, keylen) ||
1692 	    crypto_hash_digest(&desc, &sg, bodysize, digest)) {
1693 		*error = -SCTP_IERROR_NOMEM;
1694 		goto fail;
1695 	}
1696 
1697 	if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
1698 		/* Try the previous key. */
1699 		key = (char *)ep->secret_key[ep->last_key];
1700 		memset(digest, 0x00, SCTP_SIGNATURE_SIZE);
1701 		if (crypto_hash_setkey(desc.tfm, key, keylen) ||
1702 		    crypto_hash_digest(&desc, &sg, bodysize, digest)) {
1703 			*error = -SCTP_IERROR_NOMEM;
1704 			goto fail;
1705 		}
1706 
1707 		if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
1708 			/* Yikes!  Still bad signature! */
1709 			*error = -SCTP_IERROR_BAD_SIG;
1710 			goto fail;
1711 		}
1712 	}
1713 
1714 no_hmac:
1715 	/* IG Section 2.35.2:
1716 	 *  3) Compare the port numbers and the verification tag contained
1717 	 *     within the COOKIE ECHO chunk to the actual port numbers and the
1718 	 *     verification tag within the SCTP common header of the received
1719 	 *     packet. If these values do not match the packet MUST be silently
1720 	 *     discarded,
1721 	 */
1722 	if (ntohl(chunk->sctp_hdr->vtag) != bear_cookie->my_vtag) {
1723 		*error = -SCTP_IERROR_BAD_TAG;
1724 		goto fail;
1725 	}
1726 
1727 	if (chunk->sctp_hdr->source != bear_cookie->peer_addr.v4.sin_port ||
1728 	    ntohs(chunk->sctp_hdr->dest) != bear_cookie->my_port) {
1729 		*error = -SCTP_IERROR_BAD_PORTS;
1730 		goto fail;
1731 	}
1732 
1733 	/* Check to see if the cookie is stale.  If there is already
1734 	 * an association, there is no need to check cookie's expiration
1735 	 * for init collision case of lost COOKIE ACK.
1736 	 * If skb has been timestamped, then use the stamp, otherwise
1737 	 * use current time.  This introduces a small possibility that
1738 	 * that a cookie may be considered expired, but his would only slow
1739 	 * down the new association establishment instead of every packet.
1740 	 */
1741 	if (sock_flag(ep->base.sk, SOCK_TIMESTAMP))
1742 		skb_get_timestamp(skb, &tv);
1743 	else
1744 		do_gettimeofday(&tv);
1745 
1746 	if (!asoc && tv_lt(bear_cookie->expiration, tv)) {
1747 		/*
1748 		 * Section 3.3.10.3 Stale Cookie Error (3)
1749 		 *
1750 		 * Cause of error
1751 		 * ---------------
1752 		 * Stale Cookie Error:  Indicates the receipt of a valid State
1753 		 * Cookie that has expired.
1754 		 */
1755 		len = ntohs(chunk->chunk_hdr->length);
1756 		*errp = sctp_make_op_error_space(asoc, chunk, len);
1757 		if (*errp) {
1758 			suseconds_t usecs = (tv.tv_sec -
1759 				bear_cookie->expiration.tv_sec) * 1000000L +
1760 				tv.tv_usec - bear_cookie->expiration.tv_usec;
1761 			__be32 n = htonl(usecs);
1762 
1763 			sctp_init_cause(*errp, SCTP_ERROR_STALE_COOKIE,
1764 					sizeof(n));
1765 			sctp_addto_chunk(*errp, sizeof(n), &n);
1766 			*error = -SCTP_IERROR_STALE_COOKIE;
1767 		} else
1768 			*error = -SCTP_IERROR_NOMEM;
1769 
1770 		goto fail;
1771 	}
1772 
1773 	/* Make a new base association.  */
1774 	scope = sctp_scope(sctp_source(chunk));
1775 	retval = sctp_association_new(ep, ep->base.sk, scope, gfp);
1776 	if (!retval) {
1777 		*error = -SCTP_IERROR_NOMEM;
1778 		goto fail;
1779 	}
1780 
1781 	/* Set up our peer's port number.  */
1782 	retval->peer.port = ntohs(chunk->sctp_hdr->source);
1783 
1784 	/* Populate the association from the cookie.  */
1785 	memcpy(&retval->c, bear_cookie, sizeof(*bear_cookie));
1786 
1787 	if (sctp_assoc_set_bind_addr_from_cookie(retval, bear_cookie,
1788 						 GFP_ATOMIC) < 0) {
1789 		*error = -SCTP_IERROR_NOMEM;
1790 		goto fail;
1791 	}
1792 
1793 	/* Also, add the destination address. */
1794 	if (list_empty(&retval->base.bind_addr.address_list)) {
1795 		sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest,
1796 				SCTP_ADDR_SRC, GFP_ATOMIC);
1797 	}
1798 
1799 	retval->next_tsn = retval->c.initial_tsn;
1800 	retval->ctsn_ack_point = retval->next_tsn - 1;
1801 	retval->addip_serial = retval->c.initial_tsn;
1802 	retval->adv_peer_ack_point = retval->ctsn_ack_point;
1803 	retval->peer.prsctp_capable = retval->c.prsctp_capable;
1804 	retval->peer.adaptation_ind = retval->c.adaptation_ind;
1805 
1806 	/* The INIT stuff will be done by the side effects.  */
1807 	return retval;
1808 
1809 fail:
1810 	if (retval)
1811 		sctp_association_free(retval);
1812 
1813 	return NULL;
1814 
1815 malformed:
1816 	/* Yikes!  The packet is either corrupt or deliberately
1817 	 * malformed.
1818 	 */
1819 	*error = -SCTP_IERROR_MALFORMED;
1820 	goto fail;
1821 }
1822 
1823 /********************************************************************
1824  * 3rd Level Abstractions
1825  ********************************************************************/
1826 
1827 struct __sctp_missing {
1828 	__be32 num_missing;
1829 	__be16 type;
1830 }  __packed;
1831 
1832 /*
1833  * Report a missing mandatory parameter.
1834  */
sctp_process_missing_param(const struct sctp_association * asoc,sctp_param_t paramtype,struct sctp_chunk * chunk,struct sctp_chunk ** errp)1835 static int sctp_process_missing_param(const struct sctp_association *asoc,
1836 				      sctp_param_t paramtype,
1837 				      struct sctp_chunk *chunk,
1838 				      struct sctp_chunk **errp)
1839 {
1840 	struct __sctp_missing report;
1841 	__u16 len;
1842 
1843 	len = WORD_ROUND(sizeof(report));
1844 
1845 	/* Make an ERROR chunk, preparing enough room for
1846 	 * returning multiple unknown parameters.
1847 	 */
1848 	if (!*errp)
1849 		*errp = sctp_make_op_error_space(asoc, chunk, len);
1850 
1851 	if (*errp) {
1852 		report.num_missing = htonl(1);
1853 		report.type = paramtype;
1854 		sctp_init_cause(*errp, SCTP_ERROR_MISS_PARAM,
1855 				sizeof(report));
1856 		sctp_addto_chunk(*errp, sizeof(report), &report);
1857 	}
1858 
1859 	/* Stop processing this chunk. */
1860 	return 0;
1861 }
1862 
1863 /* Report an Invalid Mandatory Parameter.  */
sctp_process_inv_mandatory(const struct sctp_association * asoc,struct sctp_chunk * chunk,struct sctp_chunk ** errp)1864 static int sctp_process_inv_mandatory(const struct sctp_association *asoc,
1865 				      struct sctp_chunk *chunk,
1866 				      struct sctp_chunk **errp)
1867 {
1868 	/* Invalid Mandatory Parameter Error has no payload. */
1869 
1870 	if (!*errp)
1871 		*errp = sctp_make_op_error_space(asoc, chunk, 0);
1872 
1873 	if (*errp)
1874 		sctp_init_cause(*errp, SCTP_ERROR_INV_PARAM, 0);
1875 
1876 	/* Stop processing this chunk. */
1877 	return 0;
1878 }
1879 
sctp_process_inv_paramlength(const struct sctp_association * asoc,struct sctp_paramhdr * param,const struct sctp_chunk * chunk,struct sctp_chunk ** errp)1880 static int sctp_process_inv_paramlength(const struct sctp_association *asoc,
1881 					struct sctp_paramhdr *param,
1882 					const struct sctp_chunk *chunk,
1883 					struct sctp_chunk **errp)
1884 {
1885 	/* This is a fatal error.  Any accumulated non-fatal errors are
1886 	 * not reported.
1887 	 */
1888 	if (*errp)
1889 		sctp_chunk_free(*errp);
1890 
1891 	/* Create an error chunk and fill it in with our payload. */
1892 	*errp = sctp_make_violation_paramlen(asoc, chunk, param);
1893 
1894 	return 0;
1895 }
1896 
1897 
1898 /* Do not attempt to handle the HOST_NAME parm.  However, do
1899  * send back an indicator to the peer.
1900  */
sctp_process_hn_param(const struct sctp_association * asoc,union sctp_params param,struct sctp_chunk * chunk,struct sctp_chunk ** errp)1901 static int sctp_process_hn_param(const struct sctp_association *asoc,
1902 				 union sctp_params param,
1903 				 struct sctp_chunk *chunk,
1904 				 struct sctp_chunk **errp)
1905 {
1906 	__u16 len = ntohs(param.p->length);
1907 
1908 	/* Processing of the HOST_NAME parameter will generate an
1909 	 * ABORT.  If we've accumulated any non-fatal errors, they
1910 	 * would be unrecognized parameters and we should not include
1911 	 * them in the ABORT.
1912 	 */
1913 	if (*errp)
1914 		sctp_chunk_free(*errp);
1915 
1916 	*errp = sctp_make_op_error_space(asoc, chunk, len);
1917 
1918 	if (*errp) {
1919 		sctp_init_cause(*errp, SCTP_ERROR_DNS_FAILED, len);
1920 		sctp_addto_chunk(*errp, len, param.v);
1921 	}
1922 
1923 	/* Stop processing this chunk. */
1924 	return 0;
1925 }
1926 
sctp_verify_ext_param(union sctp_params param)1927 static int sctp_verify_ext_param(union sctp_params param)
1928 {
1929 	__u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
1930 	int have_auth = 0;
1931 	int have_asconf = 0;
1932 	int i;
1933 
1934 	for (i = 0; i < num_ext; i++) {
1935 		switch (param.ext->chunks[i]) {
1936 		    case SCTP_CID_AUTH:
1937 			    have_auth = 1;
1938 			    break;
1939 		    case SCTP_CID_ASCONF:
1940 		    case SCTP_CID_ASCONF_ACK:
1941 			    have_asconf = 1;
1942 			    break;
1943 		}
1944 	}
1945 
1946 	/* ADD-IP Security: The draft requires us to ABORT or ignore the
1947 	 * INIT/INIT-ACK if ADD-IP is listed, but AUTH is not.  Do this
1948 	 * only if ADD-IP is turned on and we are not backward-compatible
1949 	 * mode.
1950 	 */
1951 	if (sctp_addip_noauth)
1952 		return 1;
1953 
1954 	if (sctp_addip_enable && !have_auth && have_asconf)
1955 		return 0;
1956 
1957 	return 1;
1958 }
1959 
sctp_process_ext_param(struct sctp_association * asoc,union sctp_params param)1960 static void sctp_process_ext_param(struct sctp_association *asoc,
1961 				    union sctp_params param)
1962 {
1963 	__u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
1964 	int i;
1965 
1966 	for (i = 0; i < num_ext; i++) {
1967 		switch (param.ext->chunks[i]) {
1968 		    case SCTP_CID_FWD_TSN:
1969 			    if (sctp_prsctp_enable &&
1970 				!asoc->peer.prsctp_capable)
1971 				    asoc->peer.prsctp_capable = 1;
1972 			    break;
1973 		    case SCTP_CID_AUTH:
1974 			    /* if the peer reports AUTH, assume that he
1975 			     * supports AUTH.
1976 			     */
1977 			    if (sctp_auth_enable)
1978 				    asoc->peer.auth_capable = 1;
1979 			    break;
1980 		    case SCTP_CID_ASCONF:
1981 		    case SCTP_CID_ASCONF_ACK:
1982 			    if (sctp_addip_enable)
1983 				    asoc->peer.asconf_capable = 1;
1984 			    break;
1985 		    default:
1986 			    break;
1987 		}
1988 	}
1989 }
1990 
1991 /* RFC 3.2.1 & the Implementers Guide 2.2.
1992  *
1993  * The Parameter Types are encoded such that the
1994  * highest-order two bits specify the action that must be
1995  * taken if the processing endpoint does not recognize the
1996  * Parameter Type.
1997  *
1998  * 00 - Stop processing this parameter; do not process any further
1999  * 	parameters within this chunk
2000  *
2001  * 01 - Stop processing this parameter, do not process any further
2002  *	parameters within this chunk, and report the unrecognized
2003  *	parameter in an 'Unrecognized Parameter' ERROR chunk.
2004  *
2005  * 10 - Skip this parameter and continue processing.
2006  *
2007  * 11 - Skip this parameter and continue processing but
2008  *	report the unrecognized parameter in an
2009  *	'Unrecognized Parameter' ERROR chunk.
2010  *
2011  * Return value:
2012  * 	SCTP_IERROR_NO_ERROR - continue with the chunk
2013  * 	SCTP_IERROR_ERROR    - stop and report an error.
2014  * 	SCTP_IERROR_NOMEME   - out of memory.
2015  */
sctp_process_unk_param(const struct sctp_association * asoc,union sctp_params param,struct sctp_chunk * chunk,struct sctp_chunk ** errp)2016 static sctp_ierror_t sctp_process_unk_param(const struct sctp_association *asoc,
2017 					    union sctp_params param,
2018 					    struct sctp_chunk *chunk,
2019 					    struct sctp_chunk **errp)
2020 {
2021 	int retval = SCTP_IERROR_NO_ERROR;
2022 
2023 	switch (param.p->type & SCTP_PARAM_ACTION_MASK) {
2024 	case SCTP_PARAM_ACTION_DISCARD:
2025 		retval =  SCTP_IERROR_ERROR;
2026 		break;
2027 	case SCTP_PARAM_ACTION_SKIP:
2028 		break;
2029 	case SCTP_PARAM_ACTION_DISCARD_ERR:
2030 		retval =  SCTP_IERROR_ERROR;
2031 		/* Fall through */
2032 	case SCTP_PARAM_ACTION_SKIP_ERR:
2033 		/* Make an ERROR chunk, preparing enough room for
2034 		 * returning multiple unknown parameters.
2035 		 */
2036 		if (NULL == *errp)
2037 			*errp = sctp_make_op_error_fixed(asoc, chunk);
2038 
2039 		if (*errp) {
2040 			if (!sctp_init_cause_fixed(*errp, SCTP_ERROR_UNKNOWN_PARAM,
2041 					WORD_ROUND(ntohs(param.p->length))))
2042 				sctp_addto_chunk_fixed(*errp,
2043 						WORD_ROUND(ntohs(param.p->length)),
2044 						param.v);
2045 		} else {
2046 			/* If there is no memory for generating the ERROR
2047 			 * report as specified, an ABORT will be triggered
2048 			 * to the peer and the association won't be
2049 			 * established.
2050 			 */
2051 			retval = SCTP_IERROR_NOMEM;
2052 		}
2053 		break;
2054 	default:
2055 		break;
2056 	}
2057 
2058 	return retval;
2059 }
2060 
2061 /* Verify variable length parameters
2062  * Return values:
2063  * 	SCTP_IERROR_ABORT - trigger an ABORT
2064  * 	SCTP_IERROR_NOMEM - out of memory (abort)
2065  *	SCTP_IERROR_ERROR - stop processing, trigger an ERROR
2066  * 	SCTP_IERROR_NO_ERROR - continue with the chunk
2067  */
sctp_verify_param(const struct sctp_association * asoc,union sctp_params param,sctp_cid_t cid,struct sctp_chunk * chunk,struct sctp_chunk ** err_chunk)2068 static sctp_ierror_t sctp_verify_param(const struct sctp_association *asoc,
2069 					union sctp_params param,
2070 					sctp_cid_t cid,
2071 					struct sctp_chunk *chunk,
2072 					struct sctp_chunk **err_chunk)
2073 {
2074 	struct sctp_hmac_algo_param *hmacs;
2075 	int retval = SCTP_IERROR_NO_ERROR;
2076 	__u16 n_elt, id = 0;
2077 	int i;
2078 
2079 	/* FIXME - This routine is not looking at each parameter per the
2080 	 * chunk type, i.e., unrecognized parameters should be further
2081 	 * identified based on the chunk id.
2082 	 */
2083 
2084 	switch (param.p->type) {
2085 	case SCTP_PARAM_IPV4_ADDRESS:
2086 	case SCTP_PARAM_IPV6_ADDRESS:
2087 	case SCTP_PARAM_COOKIE_PRESERVATIVE:
2088 	case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2089 	case SCTP_PARAM_STATE_COOKIE:
2090 	case SCTP_PARAM_HEARTBEAT_INFO:
2091 	case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2092 	case SCTP_PARAM_ECN_CAPABLE:
2093 	case SCTP_PARAM_ADAPTATION_LAYER_IND:
2094 		break;
2095 
2096 	case SCTP_PARAM_SUPPORTED_EXT:
2097 		if (!sctp_verify_ext_param(param))
2098 			return SCTP_IERROR_ABORT;
2099 		break;
2100 
2101 	case SCTP_PARAM_SET_PRIMARY:
2102 		if (sctp_addip_enable)
2103 			break;
2104 		goto fallthrough;
2105 
2106 	case SCTP_PARAM_HOST_NAME_ADDRESS:
2107 		/* Tell the peer, we won't support this param.  */
2108 		sctp_process_hn_param(asoc, param, chunk, err_chunk);
2109 		retval = SCTP_IERROR_ABORT;
2110 		break;
2111 
2112 	case SCTP_PARAM_FWD_TSN_SUPPORT:
2113 		if (sctp_prsctp_enable)
2114 			break;
2115 		goto fallthrough;
2116 
2117 	case SCTP_PARAM_RANDOM:
2118 		if (!sctp_auth_enable)
2119 			goto fallthrough;
2120 
2121 		/* SCTP-AUTH: Secion 6.1
2122 		 * If the random number is not 32 byte long the association
2123 		 * MUST be aborted.  The ABORT chunk SHOULD contain the error
2124 		 * cause 'Protocol Violation'.
2125 		 */
2126 		if (SCTP_AUTH_RANDOM_LENGTH !=
2127 			ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) {
2128 			sctp_process_inv_paramlength(asoc, param.p,
2129 							chunk, err_chunk);
2130 			retval = SCTP_IERROR_ABORT;
2131 		}
2132 		break;
2133 
2134 	case SCTP_PARAM_CHUNKS:
2135 		if (!sctp_auth_enable)
2136 			goto fallthrough;
2137 
2138 		/* SCTP-AUTH: Section 3.2
2139 		 * The CHUNKS parameter MUST be included once in the INIT or
2140 		 *  INIT-ACK chunk if the sender wants to receive authenticated
2141 		 *  chunks.  Its maximum length is 260 bytes.
2142 		 */
2143 		if (260 < ntohs(param.p->length)) {
2144 			sctp_process_inv_paramlength(asoc, param.p,
2145 						     chunk, err_chunk);
2146 			retval = SCTP_IERROR_ABORT;
2147 		}
2148 		break;
2149 
2150 	case SCTP_PARAM_HMAC_ALGO:
2151 		if (!sctp_auth_enable)
2152 			goto fallthrough;
2153 
2154 		hmacs = (struct sctp_hmac_algo_param *)param.p;
2155 		n_elt = (ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) >> 1;
2156 
2157 		/* SCTP-AUTH: Section 6.1
2158 		 * The HMAC algorithm based on SHA-1 MUST be supported and
2159 		 * included in the HMAC-ALGO parameter.
2160 		 */
2161 		for (i = 0; i < n_elt; i++) {
2162 			id = ntohs(hmacs->hmac_ids[i]);
2163 
2164 			if (id == SCTP_AUTH_HMAC_ID_SHA1)
2165 				break;
2166 		}
2167 
2168 		if (id != SCTP_AUTH_HMAC_ID_SHA1) {
2169 			sctp_process_inv_paramlength(asoc, param.p, chunk,
2170 						     err_chunk);
2171 			retval = SCTP_IERROR_ABORT;
2172 		}
2173 		break;
2174 fallthrough:
2175 	default:
2176 		SCTP_DEBUG_PRINTK("Unrecognized param: %d for chunk %d.\n",
2177 				ntohs(param.p->type), cid);
2178 		retval = sctp_process_unk_param(asoc, param, chunk, err_chunk);
2179 		break;
2180 	}
2181 	return retval;
2182 }
2183 
2184 /* Verify the INIT packet before we process it.  */
sctp_verify_init(const struct sctp_association * asoc,sctp_cid_t cid,sctp_init_chunk_t * peer_init,struct sctp_chunk * chunk,struct sctp_chunk ** errp)2185 int sctp_verify_init(const struct sctp_association *asoc,
2186 		     sctp_cid_t cid,
2187 		     sctp_init_chunk_t *peer_init,
2188 		     struct sctp_chunk *chunk,
2189 		     struct sctp_chunk **errp)
2190 {
2191 	union sctp_params param;
2192 	int has_cookie = 0;
2193 	int result;
2194 
2195 	/* Verify stream values are non-zero. */
2196 	if ((0 == peer_init->init_hdr.num_outbound_streams) ||
2197 	    (0 == peer_init->init_hdr.num_inbound_streams) ||
2198 	    (0 == peer_init->init_hdr.init_tag) ||
2199 	    (SCTP_DEFAULT_MINWINDOW > ntohl(peer_init->init_hdr.a_rwnd))) {
2200 
2201 		return sctp_process_inv_mandatory(asoc, chunk, errp);
2202 	}
2203 
2204 	/* Check for missing mandatory parameters.  */
2205 	sctp_walk_params(param, peer_init, init_hdr.params) {
2206 
2207 		if (SCTP_PARAM_STATE_COOKIE == param.p->type)
2208 			has_cookie = 1;
2209 
2210 	} /* for (loop through all parameters) */
2211 
2212 	/* There is a possibility that a parameter length was bad and
2213 	 * in that case we would have stoped walking the parameters.
2214 	 * The current param.p would point at the bad one.
2215 	 * Current consensus on the mailing list is to generate a PROTOCOL
2216 	 * VIOLATION error.  We build the ERROR chunk here and let the normal
2217 	 * error handling code build and send the packet.
2218 	 */
2219 	if (param.v != (void*)chunk->chunk_end)
2220 		return sctp_process_inv_paramlength(asoc, param.p, chunk, errp);
2221 
2222 	/* The only missing mandatory param possible today is
2223 	 * the state cookie for an INIT-ACK chunk.
2224 	 */
2225 	if ((SCTP_CID_INIT_ACK == cid) && !has_cookie)
2226 		return sctp_process_missing_param(asoc, SCTP_PARAM_STATE_COOKIE,
2227 						  chunk, errp);
2228 
2229 	/* Verify all the variable length parameters */
2230 	sctp_walk_params(param, peer_init, init_hdr.params) {
2231 
2232 		result = sctp_verify_param(asoc, param, cid, chunk, errp);
2233 		switch (result) {
2234 		    case SCTP_IERROR_ABORT:
2235 		    case SCTP_IERROR_NOMEM:
2236 				return 0;
2237 		    case SCTP_IERROR_ERROR:
2238 				return 1;
2239 		    case SCTP_IERROR_NO_ERROR:
2240 		    default:
2241 				break;
2242 		}
2243 
2244 	} /* for (loop through all parameters) */
2245 
2246 	return 1;
2247 }
2248 
2249 /* Unpack the parameters in an INIT packet into an association.
2250  * Returns 0 on failure, else success.
2251  * FIXME:  This is an association method.
2252  */
sctp_process_init(struct sctp_association * asoc,struct sctp_chunk * chunk,const union sctp_addr * peer_addr,sctp_init_chunk_t * peer_init,gfp_t gfp)2253 int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,
2254 		      const union sctp_addr *peer_addr,
2255 		      sctp_init_chunk_t *peer_init, gfp_t gfp)
2256 {
2257 	union sctp_params param;
2258 	struct sctp_transport *transport;
2259 	struct list_head *pos, *temp;
2260 	struct sctp_af *af;
2261 	union sctp_addr addr;
2262 	char *cookie;
2263 	int src_match = 0;
2264 
2265 	/* We must include the address that the INIT packet came from.
2266 	 * This is the only address that matters for an INIT packet.
2267 	 * When processing a COOKIE ECHO, we retrieve the from address
2268 	 * of the INIT from the cookie.
2269 	 */
2270 
2271 	/* This implementation defaults to making the first transport
2272 	 * added as the primary transport.  The source address seems to
2273 	 * be a a better choice than any of the embedded addresses.
2274 	 */
2275 	if(!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
2276 		goto nomem;
2277 
2278 	if (sctp_cmp_addr_exact(sctp_source(chunk), peer_addr))
2279 		src_match = 1;
2280 
2281 	/* Process the initialization parameters.  */
2282 	sctp_walk_params(param, peer_init, init_hdr.params) {
2283 		if (!src_match && (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
2284 		    param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
2285 			af = sctp_get_af_specific(param_type2af(param.p->type));
2286 			af->from_addr_param(&addr, param.addr,
2287 					    chunk->sctp_hdr->source, 0);
2288 			if (sctp_cmp_addr_exact(sctp_source(chunk), &addr))
2289 				src_match = 1;
2290 		}
2291 
2292 		if (!sctp_process_param(asoc, param, peer_addr, gfp))
2293 			goto clean_up;
2294 	}
2295 
2296 	/* source address of chunk may not match any valid address */
2297 	if (!src_match)
2298 		goto clean_up;
2299 
2300 	/* AUTH: After processing the parameters, make sure that we
2301 	 * have all the required info to potentially do authentications.
2302 	 */
2303 	if (asoc->peer.auth_capable && (!asoc->peer.peer_random ||
2304 					!asoc->peer.peer_hmacs))
2305 		asoc->peer.auth_capable = 0;
2306 
2307 	/* In a non-backward compatible mode, if the peer claims
2308 	 * support for ADD-IP but not AUTH,  the ADD-IP spec states
2309 	 * that we MUST ABORT the association. Section 6.  The section
2310 	 * also give us an option to silently ignore the packet, which
2311 	 * is what we'll do here.
2312 	 */
2313 	if (!sctp_addip_noauth &&
2314 	     (asoc->peer.asconf_capable && !asoc->peer.auth_capable)) {
2315 		asoc->peer.addip_disabled_mask |= (SCTP_PARAM_ADD_IP |
2316 						  SCTP_PARAM_DEL_IP |
2317 						  SCTP_PARAM_SET_PRIMARY);
2318 		asoc->peer.asconf_capable = 0;
2319 		goto clean_up;
2320 	}
2321 
2322 	/* Walk list of transports, removing transports in the UNKNOWN state. */
2323 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2324 		transport = list_entry(pos, struct sctp_transport, transports);
2325 		if (transport->state == SCTP_UNKNOWN) {
2326 			sctp_assoc_rm_peer(asoc, transport);
2327 		}
2328 	}
2329 
2330 	/* The fixed INIT headers are always in network byte
2331 	 * order.
2332 	 */
2333 	asoc->peer.i.init_tag =
2334 		ntohl(peer_init->init_hdr.init_tag);
2335 	asoc->peer.i.a_rwnd =
2336 		ntohl(peer_init->init_hdr.a_rwnd);
2337 	asoc->peer.i.num_outbound_streams =
2338 		ntohs(peer_init->init_hdr.num_outbound_streams);
2339 	asoc->peer.i.num_inbound_streams =
2340 		ntohs(peer_init->init_hdr.num_inbound_streams);
2341 	asoc->peer.i.initial_tsn =
2342 		ntohl(peer_init->init_hdr.initial_tsn);
2343 
2344 	/* Apply the upper bounds for output streams based on peer's
2345 	 * number of inbound streams.
2346 	 */
2347 	if (asoc->c.sinit_num_ostreams  >
2348 	    ntohs(peer_init->init_hdr.num_inbound_streams)) {
2349 		asoc->c.sinit_num_ostreams =
2350 			ntohs(peer_init->init_hdr.num_inbound_streams);
2351 	}
2352 
2353 	if (asoc->c.sinit_max_instreams >
2354 	    ntohs(peer_init->init_hdr.num_outbound_streams)) {
2355 		asoc->c.sinit_max_instreams =
2356 			ntohs(peer_init->init_hdr.num_outbound_streams);
2357 	}
2358 
2359 	/* Copy Initiation tag from INIT to VT_peer in cookie.   */
2360 	asoc->c.peer_vtag = asoc->peer.i.init_tag;
2361 
2362 	/* Peer Rwnd   : Current calculated value of the peer's rwnd.  */
2363 	asoc->peer.rwnd = asoc->peer.i.a_rwnd;
2364 
2365 	/* Copy cookie in case we need to resend COOKIE-ECHO. */
2366 	cookie = asoc->peer.cookie;
2367 	if (cookie) {
2368 		asoc->peer.cookie = kmemdup(cookie, asoc->peer.cookie_len, gfp);
2369 		if (!asoc->peer.cookie)
2370 			goto clean_up;
2371 	}
2372 
2373 	/* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily
2374 	 * high (for example, implementations MAY use the size of the receiver
2375 	 * advertised window).
2376 	 */
2377 	list_for_each_entry(transport, &asoc->peer.transport_addr_list,
2378 			transports) {
2379 		transport->ssthresh = asoc->peer.i.a_rwnd;
2380 	}
2381 
2382 	/* Set up the TSN tracking pieces.  */
2383 	if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
2384 				asoc->peer.i.initial_tsn, gfp))
2385 		goto clean_up;
2386 
2387 	/* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
2388 	 *
2389 	 * The stream sequence number in all the streams shall start
2390 	 * from 0 when the association is established.  Also, when the
2391 	 * stream sequence number reaches the value 65535 the next
2392 	 * stream sequence number shall be set to 0.
2393 	 */
2394 
2395 	/* Allocate storage for the negotiated streams if it is not a temporary
2396 	 * association.
2397 	 */
2398 	if (!asoc->temp) {
2399 		int error;
2400 
2401 		asoc->ssnmap = sctp_ssnmap_new(asoc->c.sinit_max_instreams,
2402 					       asoc->c.sinit_num_ostreams, gfp);
2403 		if (!asoc->ssnmap)
2404 			goto clean_up;
2405 
2406 		error = sctp_assoc_set_id(asoc, gfp);
2407 		if (error)
2408 			goto clean_up;
2409 	}
2410 
2411 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
2412 	 *
2413 	 * When an endpoint has an ASCONF signaled change to be sent to the
2414 	 * remote endpoint it should do the following:
2415 	 * ...
2416 	 * A2) A serial number should be assigned to the Chunk. The serial
2417 	 * number should be a monotonically increasing number. All serial
2418 	 * numbers are defined to be initialized at the start of the
2419 	 * association to the same value as the Initial TSN.
2420 	 */
2421 	asoc->peer.addip_serial = asoc->peer.i.initial_tsn - 1;
2422 	return 1;
2423 
2424 clean_up:
2425 	/* Release the transport structures. */
2426 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2427 		transport = list_entry(pos, struct sctp_transport, transports);
2428 		if (transport->state != SCTP_ACTIVE)
2429 			sctp_assoc_rm_peer(asoc, transport);
2430 	}
2431 
2432 nomem:
2433 	return 0;
2434 }
2435 
2436 
2437 /* Update asoc with the option described in param.
2438  *
2439  * RFC2960 3.3.2.1 Optional/Variable Length Parameters in INIT
2440  *
2441  * asoc is the association to update.
2442  * param is the variable length parameter to use for update.
2443  * cid tells us if this is an INIT, INIT ACK or COOKIE ECHO.
2444  * If the current packet is an INIT we want to minimize the amount of
2445  * work we do.  In particular, we should not build transport
2446  * structures for the addresses.
2447  */
sctp_process_param(struct sctp_association * asoc,union sctp_params param,const union sctp_addr * peer_addr,gfp_t gfp)2448 static int sctp_process_param(struct sctp_association *asoc,
2449 			      union sctp_params param,
2450 			      const union sctp_addr *peer_addr,
2451 			      gfp_t gfp)
2452 {
2453 	union sctp_addr addr;
2454 	int i;
2455 	__u16 sat;
2456 	int retval = 1;
2457 	sctp_scope_t scope;
2458 	time_t stale;
2459 	struct sctp_af *af;
2460 	union sctp_addr_param *addr_param;
2461 	struct sctp_transport *t;
2462 
2463 	/* We maintain all INIT parameters in network byte order all the
2464 	 * time.  This allows us to not worry about whether the parameters
2465 	 * came from a fresh INIT, and INIT ACK, or were stored in a cookie.
2466 	 */
2467 	switch (param.p->type) {
2468 	case SCTP_PARAM_IPV6_ADDRESS:
2469 		if (PF_INET6 != asoc->base.sk->sk_family)
2470 			break;
2471 		goto do_addr_param;
2472 
2473 	case SCTP_PARAM_IPV4_ADDRESS:
2474 		/* v4 addresses are not allowed on v6-only socket */
2475 		if (ipv6_only_sock(asoc->base.sk))
2476 			break;
2477 do_addr_param:
2478 		af = sctp_get_af_specific(param_type2af(param.p->type));
2479 		af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
2480 		scope = sctp_scope(peer_addr);
2481 		if (sctp_in_scope(&addr, scope))
2482 			if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
2483 				return 0;
2484 		break;
2485 
2486 	case SCTP_PARAM_COOKIE_PRESERVATIVE:
2487 		if (!sctp_cookie_preserve_enable)
2488 			break;
2489 
2490 		stale = ntohl(param.life->lifespan_increment);
2491 
2492 		/* Suggested Cookie Life span increment's unit is msec,
2493 		 * (1/1000sec).
2494 		 */
2495 		asoc->cookie_life.tv_sec += stale / 1000;
2496 		asoc->cookie_life.tv_usec += (stale % 1000) * 1000;
2497 		break;
2498 
2499 	case SCTP_PARAM_HOST_NAME_ADDRESS:
2500 		SCTP_DEBUG_PRINTK("unimplemented SCTP_HOST_NAME_ADDRESS\n");
2501 		break;
2502 
2503 	case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2504 		/* Turn off the default values first so we'll know which
2505 		 * ones are really set by the peer.
2506 		 */
2507 		asoc->peer.ipv4_address = 0;
2508 		asoc->peer.ipv6_address = 0;
2509 
2510 		/* Assume that peer supports the address family
2511 		 * by which it sends a packet.
2512 		 */
2513 		if (peer_addr->sa.sa_family == AF_INET6)
2514 			asoc->peer.ipv6_address = 1;
2515 		else if (peer_addr->sa.sa_family == AF_INET)
2516 			asoc->peer.ipv4_address = 1;
2517 
2518 		/* Cycle through address types; avoid divide by 0. */
2519 		sat = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2520 		if (sat)
2521 			sat /= sizeof(__u16);
2522 
2523 		for (i = 0; i < sat; ++i) {
2524 			switch (param.sat->types[i]) {
2525 			case SCTP_PARAM_IPV4_ADDRESS:
2526 				asoc->peer.ipv4_address = 1;
2527 				break;
2528 
2529 			case SCTP_PARAM_IPV6_ADDRESS:
2530 				if (PF_INET6 == asoc->base.sk->sk_family)
2531 					asoc->peer.ipv6_address = 1;
2532 				break;
2533 
2534 			case SCTP_PARAM_HOST_NAME_ADDRESS:
2535 				asoc->peer.hostname_address = 1;
2536 				break;
2537 
2538 			default: /* Just ignore anything else.  */
2539 				break;
2540 			}
2541 		}
2542 		break;
2543 
2544 	case SCTP_PARAM_STATE_COOKIE:
2545 		asoc->peer.cookie_len =
2546 			ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2547 		asoc->peer.cookie = param.cookie->body;
2548 		break;
2549 
2550 	case SCTP_PARAM_HEARTBEAT_INFO:
2551 		/* Would be odd to receive, but it causes no problems. */
2552 		break;
2553 
2554 	case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2555 		/* Rejected during verify stage. */
2556 		break;
2557 
2558 	case SCTP_PARAM_ECN_CAPABLE:
2559 		asoc->peer.ecn_capable = 1;
2560 		break;
2561 
2562 	case SCTP_PARAM_ADAPTATION_LAYER_IND:
2563 		asoc->peer.adaptation_ind = ntohl(param.aind->adaptation_ind);
2564 		break;
2565 
2566 	case SCTP_PARAM_SET_PRIMARY:
2567 		if (!sctp_addip_enable)
2568 			goto fall_through;
2569 
2570 		addr_param = param.v + sizeof(sctp_addip_param_t);
2571 
2572 		af = sctp_get_af_specific(param_type2af(param.p->type));
2573 		af->from_addr_param(&addr, addr_param,
2574 				    htons(asoc->peer.port), 0);
2575 
2576 		/* if the address is invalid, we can't process it.
2577 		 * XXX: see spec for what to do.
2578 		 */
2579 		if (!af->addr_valid(&addr, NULL, NULL))
2580 			break;
2581 
2582 		t = sctp_assoc_lookup_paddr(asoc, &addr);
2583 		if (!t)
2584 			break;
2585 
2586 		sctp_assoc_set_primary(asoc, t);
2587 		break;
2588 
2589 	case SCTP_PARAM_SUPPORTED_EXT:
2590 		sctp_process_ext_param(asoc, param);
2591 		break;
2592 
2593 	case SCTP_PARAM_FWD_TSN_SUPPORT:
2594 		if (sctp_prsctp_enable) {
2595 			asoc->peer.prsctp_capable = 1;
2596 			break;
2597 		}
2598 		/* Fall Through */
2599 		goto fall_through;
2600 
2601 	case SCTP_PARAM_RANDOM:
2602 		if (!sctp_auth_enable)
2603 			goto fall_through;
2604 
2605 		/* Save peer's random parameter */
2606 		asoc->peer.peer_random = kmemdup(param.p,
2607 					    ntohs(param.p->length), gfp);
2608 		if (!asoc->peer.peer_random) {
2609 			retval = 0;
2610 			break;
2611 		}
2612 		break;
2613 
2614 	case SCTP_PARAM_HMAC_ALGO:
2615 		if (!sctp_auth_enable)
2616 			goto fall_through;
2617 
2618 		/* Save peer's HMAC list */
2619 		asoc->peer.peer_hmacs = kmemdup(param.p,
2620 					    ntohs(param.p->length), gfp);
2621 		if (!asoc->peer.peer_hmacs) {
2622 			retval = 0;
2623 			break;
2624 		}
2625 
2626 		/* Set the default HMAC the peer requested*/
2627 		sctp_auth_asoc_set_default_hmac(asoc, param.hmac_algo);
2628 		break;
2629 
2630 	case SCTP_PARAM_CHUNKS:
2631 		if (!sctp_auth_enable)
2632 			goto fall_through;
2633 
2634 		asoc->peer.peer_chunks = kmemdup(param.p,
2635 					    ntohs(param.p->length), gfp);
2636 		if (!asoc->peer.peer_chunks)
2637 			retval = 0;
2638 		break;
2639 fall_through:
2640 	default:
2641 		/* Any unrecognized parameters should have been caught
2642 		 * and handled by sctp_verify_param() which should be
2643 		 * called prior to this routine.  Simply log the error
2644 		 * here.
2645 		 */
2646 		SCTP_DEBUG_PRINTK("Ignoring param: %d for association %p.\n",
2647 				  ntohs(param.p->type), asoc);
2648 		break;
2649 	}
2650 
2651 	return retval;
2652 }
2653 
2654 /* Select a new verification tag.  */
sctp_generate_tag(const struct sctp_endpoint * ep)2655 __u32 sctp_generate_tag(const struct sctp_endpoint *ep)
2656 {
2657 	/* I believe that this random number generator complies with RFC1750.
2658 	 * A tag of 0 is reserved for special cases (e.g. INIT).
2659 	 */
2660 	__u32 x;
2661 
2662 	do {
2663 		get_random_bytes(&x, sizeof(__u32));
2664 	} while (x == 0);
2665 
2666 	return x;
2667 }
2668 
2669 /* Select an initial TSN to send during startup.  */
sctp_generate_tsn(const struct sctp_endpoint * ep)2670 __u32 sctp_generate_tsn(const struct sctp_endpoint *ep)
2671 {
2672 	__u32 retval;
2673 
2674 	get_random_bytes(&retval, sizeof(__u32));
2675 	return retval;
2676 }
2677 
2678 /*
2679  * ADDIP 3.1.1 Address Configuration Change Chunk (ASCONF)
2680  *      0                   1                   2                   3
2681  *      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
2682  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2683  *     | Type = 0xC1   |  Chunk Flags  |      Chunk Length             |
2684  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2685  *     |                       Serial Number                           |
2686  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2687  *     |                    Address Parameter                          |
2688  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2689  *     |                     ASCONF Parameter #1                       |
2690  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2691  *     \                                                               \
2692  *     /                             ....                              /
2693  *     \                                                               \
2694  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2695  *     |                     ASCONF Parameter #N                       |
2696  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2697  *
2698  * Address Parameter and other parameter will not be wrapped in this function
2699  */
sctp_make_asconf(struct sctp_association * asoc,union sctp_addr * addr,int vparam_len)2700 static struct sctp_chunk *sctp_make_asconf(struct sctp_association *asoc,
2701 					   union sctp_addr *addr,
2702 					   int vparam_len)
2703 {
2704 	sctp_addiphdr_t asconf;
2705 	struct sctp_chunk *retval;
2706 	int length = sizeof(asconf) + vparam_len;
2707 	union sctp_addr_param addrparam;
2708 	int addrlen;
2709 	struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
2710 
2711 	addrlen = af->to_addr_param(addr, &addrparam);
2712 	if (!addrlen)
2713 		return NULL;
2714 	length += addrlen;
2715 
2716 	/* Create the chunk.  */
2717 	retval = sctp_make_chunk(asoc, SCTP_CID_ASCONF, 0, length);
2718 	if (!retval)
2719 		return NULL;
2720 
2721 	asconf.serial = htonl(asoc->addip_serial++);
2722 
2723 	retval->subh.addip_hdr =
2724 		sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2725 	retval->param_hdr.v =
2726 		sctp_addto_chunk(retval, addrlen, &addrparam);
2727 
2728 	return retval;
2729 }
2730 
2731 /* ADDIP
2732  * 3.2.1 Add IP Address
2733  * 	0                   1                   2                   3
2734  * 	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
2735  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2736  *     |        Type = 0xC001          |    Length = Variable          |
2737  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2738  *     |               ASCONF-Request Correlation ID                   |
2739  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2740  *     |                       Address Parameter                       |
2741  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2742  *
2743  * 3.2.2 Delete IP Address
2744  * 	0                   1                   2                   3
2745  * 	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
2746  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2747  *     |        Type = 0xC002          |    Length = Variable          |
2748  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2749  *     |               ASCONF-Request Correlation ID                   |
2750  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2751  *     |                       Address Parameter                       |
2752  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2753  *
2754  */
sctp_make_asconf_update_ip(struct sctp_association * asoc,union sctp_addr * laddr,struct sockaddr * addrs,int addrcnt,__be16 flags)2755 struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *asoc,
2756 					      union sctp_addr	      *laddr,
2757 					      struct sockaddr	      *addrs,
2758 					      int		      addrcnt,
2759 					      __be16		      flags)
2760 {
2761 	sctp_addip_param_t	param;
2762 	struct sctp_chunk	*retval;
2763 	union sctp_addr_param	addr_param;
2764 	union sctp_addr		*addr;
2765 	void			*addr_buf;
2766 	struct sctp_af		*af;
2767 	int			paramlen = sizeof(param);
2768 	int			addr_param_len = 0;
2769 	int 			totallen = 0;
2770 	int 			i;
2771 	int			del_pickup = 0;
2772 
2773 	/* Get total length of all the address parameters. */
2774 	addr_buf = addrs;
2775 	for (i = 0; i < addrcnt; i++) {
2776 		addr = addr_buf;
2777 		af = sctp_get_af_specific(addr->v4.sin_family);
2778 		addr_param_len = af->to_addr_param(addr, &addr_param);
2779 
2780 		totallen += paramlen;
2781 		totallen += addr_param_len;
2782 
2783 		addr_buf += af->sockaddr_len;
2784 		if (asoc->asconf_addr_del_pending && !del_pickup) {
2785 			/* reuse the parameter length from the same scope one */
2786 			totallen += paramlen;
2787 			totallen += addr_param_len;
2788 			del_pickup = 1;
2789 			SCTP_DEBUG_PRINTK("mkasconf_update_ip: picked same-scope del_pending addr, totallen for all addresses is %d\n", totallen);
2790 		}
2791 	}
2792 
2793 	/* Create an asconf chunk with the required length. */
2794 	retval = sctp_make_asconf(asoc, laddr, totallen);
2795 	if (!retval)
2796 		return NULL;
2797 
2798 	/* Add the address parameters to the asconf chunk. */
2799 	addr_buf = addrs;
2800 	for (i = 0; i < addrcnt; i++) {
2801 		addr = addr_buf;
2802 		af = sctp_get_af_specific(addr->v4.sin_family);
2803 		addr_param_len = af->to_addr_param(addr, &addr_param);
2804 		param.param_hdr.type = flags;
2805 		param.param_hdr.length = htons(paramlen + addr_param_len);
2806 		param.crr_id = i;
2807 
2808 		sctp_addto_chunk(retval, paramlen, &param);
2809 		sctp_addto_chunk(retval, addr_param_len, &addr_param);
2810 
2811 		addr_buf += af->sockaddr_len;
2812 	}
2813 	if (flags == SCTP_PARAM_ADD_IP && del_pickup) {
2814 		addr = asoc->asconf_addr_del_pending;
2815 		af = sctp_get_af_specific(addr->v4.sin_family);
2816 		addr_param_len = af->to_addr_param(addr, &addr_param);
2817 		param.param_hdr.type = SCTP_PARAM_DEL_IP;
2818 		param.param_hdr.length = htons(paramlen + addr_param_len);
2819 		param.crr_id = i;
2820 
2821 		sctp_addto_chunk(retval, paramlen, &param);
2822 		sctp_addto_chunk(retval, addr_param_len, &addr_param);
2823 	}
2824 	return retval;
2825 }
2826 
2827 /* ADDIP
2828  * 3.2.4 Set Primary IP Address
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 =0xC004           |    Length = Variable          |
2833  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2834  *     |               ASCONF-Request Correlation ID                   |
2835  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2836  *     |                       Address Parameter                       |
2837  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2838  *
2839  * Create an ASCONF chunk with Set Primary IP address parameter.
2840  */
sctp_make_asconf_set_prim(struct sctp_association * asoc,union sctp_addr * addr)2841 struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
2842 					     union sctp_addr *addr)
2843 {
2844 	sctp_addip_param_t	param;
2845 	struct sctp_chunk 	*retval;
2846 	int 			len = sizeof(param);
2847 	union sctp_addr_param	addrparam;
2848 	int			addrlen;
2849 	struct sctp_af		*af = sctp_get_af_specific(addr->v4.sin_family);
2850 
2851 	addrlen = af->to_addr_param(addr, &addrparam);
2852 	if (!addrlen)
2853 		return NULL;
2854 	len += addrlen;
2855 
2856 	/* Create the chunk and make asconf header. */
2857 	retval = sctp_make_asconf(asoc, addr, len);
2858 	if (!retval)
2859 		return NULL;
2860 
2861 	param.param_hdr.type = SCTP_PARAM_SET_PRIMARY;
2862 	param.param_hdr.length = htons(len);
2863 	param.crr_id = 0;
2864 
2865 	sctp_addto_chunk(retval, sizeof(param), &param);
2866 	sctp_addto_chunk(retval, addrlen, &addrparam);
2867 
2868 	return retval;
2869 }
2870 
2871 /* ADDIP 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
2872  *      0                   1                   2                   3
2873  *      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
2874  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2875  *     | Type = 0x80   |  Chunk Flags  |      Chunk Length             |
2876  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2877  *     |                       Serial Number                           |
2878  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2879  *     |                 ASCONF Parameter Response#1                   |
2880  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2881  *     \                                                               \
2882  *     /                             ....                              /
2883  *     \                                                               \
2884  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2885  *     |                 ASCONF Parameter Response#N                   |
2886  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2887  *
2888  * Create an ASCONF_ACK chunk with enough space for the parameter responses.
2889  */
sctp_make_asconf_ack(const struct sctp_association * asoc,__u32 serial,int vparam_len)2890 static struct sctp_chunk *sctp_make_asconf_ack(const struct sctp_association *asoc,
2891 					       __u32 serial, int vparam_len)
2892 {
2893 	sctp_addiphdr_t		asconf;
2894 	struct sctp_chunk	*retval;
2895 	int			length = sizeof(asconf) + vparam_len;
2896 
2897 	/* Create the chunk.  */
2898 	retval = sctp_make_chunk(asoc, SCTP_CID_ASCONF_ACK, 0, length);
2899 	if (!retval)
2900 		return NULL;
2901 
2902 	asconf.serial = htonl(serial);
2903 
2904 	retval->subh.addip_hdr =
2905 		sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2906 
2907 	return retval;
2908 }
2909 
2910 /* Add response parameters to an ASCONF_ACK chunk. */
sctp_add_asconf_response(struct sctp_chunk * chunk,__be32 crr_id,__be16 err_code,sctp_addip_param_t * asconf_param)2911 static void sctp_add_asconf_response(struct sctp_chunk *chunk, __be32 crr_id,
2912 			      __be16 err_code, sctp_addip_param_t *asconf_param)
2913 {
2914 	sctp_addip_param_t 	ack_param;
2915 	sctp_errhdr_t		err_param;
2916 	int			asconf_param_len = 0;
2917 	int			err_param_len = 0;
2918 	__be16			response_type;
2919 
2920 	if (SCTP_ERROR_NO_ERROR == err_code) {
2921 		response_type = SCTP_PARAM_SUCCESS_REPORT;
2922 	} else {
2923 		response_type = SCTP_PARAM_ERR_CAUSE;
2924 		err_param_len = sizeof(err_param);
2925 		if (asconf_param)
2926 			asconf_param_len =
2927 				 ntohs(asconf_param->param_hdr.length);
2928 	}
2929 
2930 	/* Add Success Indication or Error Cause Indication parameter. */
2931 	ack_param.param_hdr.type = response_type;
2932 	ack_param.param_hdr.length = htons(sizeof(ack_param) +
2933 					   err_param_len +
2934 					   asconf_param_len);
2935 	ack_param.crr_id = crr_id;
2936 	sctp_addto_chunk(chunk, sizeof(ack_param), &ack_param);
2937 
2938 	if (SCTP_ERROR_NO_ERROR == err_code)
2939 		return;
2940 
2941 	/* Add Error Cause parameter. */
2942 	err_param.cause = err_code;
2943 	err_param.length = htons(err_param_len + asconf_param_len);
2944 	sctp_addto_chunk(chunk, err_param_len, &err_param);
2945 
2946 	/* Add the failed TLV copied from ASCONF chunk. */
2947 	if (asconf_param)
2948 		sctp_addto_chunk(chunk, asconf_param_len, asconf_param);
2949 }
2950 
2951 /* Process a asconf parameter. */
sctp_process_asconf_param(struct sctp_association * asoc,struct sctp_chunk * asconf,sctp_addip_param_t * asconf_param)2952 static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
2953 				       struct sctp_chunk *asconf,
2954 				       sctp_addip_param_t *asconf_param)
2955 {
2956 	struct sctp_transport *peer;
2957 	struct sctp_af *af;
2958 	union sctp_addr	addr;
2959 	union sctp_addr_param *addr_param;
2960 
2961 	addr_param = (void *)asconf_param + sizeof(sctp_addip_param_t);
2962 
2963 	if (asconf_param->param_hdr.type != SCTP_PARAM_ADD_IP &&
2964 	    asconf_param->param_hdr.type != SCTP_PARAM_DEL_IP &&
2965 	    asconf_param->param_hdr.type != SCTP_PARAM_SET_PRIMARY)
2966 		return SCTP_ERROR_UNKNOWN_PARAM;
2967 
2968 	switch (addr_param->p.type) {
2969 	case SCTP_PARAM_IPV6_ADDRESS:
2970 		if (!asoc->peer.ipv6_address)
2971 			return SCTP_ERROR_DNS_FAILED;
2972 		break;
2973 	case SCTP_PARAM_IPV4_ADDRESS:
2974 		if (!asoc->peer.ipv4_address)
2975 			return SCTP_ERROR_DNS_FAILED;
2976 		break;
2977 	default:
2978 		return SCTP_ERROR_DNS_FAILED;
2979 	}
2980 
2981 	af = sctp_get_af_specific(param_type2af(addr_param->p.type));
2982 	if (unlikely(!af))
2983 		return SCTP_ERROR_DNS_FAILED;
2984 
2985 	af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);
2986 
2987 	/* ADDIP 4.2.1  This parameter MUST NOT contain a broadcast
2988 	 * or multicast address.
2989 	 * (note: wildcard is permitted and requires special handling so
2990 	 *  make sure we check for that)
2991 	 */
2992 	if (!af->is_any(&addr) && !af->addr_valid(&addr, NULL, asconf->skb))
2993 		return SCTP_ERROR_DNS_FAILED;
2994 
2995 	switch (asconf_param->param_hdr.type) {
2996 	case SCTP_PARAM_ADD_IP:
2997 		/* Section 4.2.1:
2998 		 * If the address 0.0.0.0 or ::0 is provided, the source
2999 		 * address of the packet MUST be added.
3000 		 */
3001 		if (af->is_any(&addr))
3002 			memcpy(&addr, &asconf->source, sizeof(addr));
3003 
3004 		/* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
3005 		 * request and does not have the local resources to add this
3006 		 * new address to the association, it MUST return an Error
3007 		 * Cause TLV set to the new error code 'Operation Refused
3008 		 * Due to Resource Shortage'.
3009 		 */
3010 
3011 		peer = sctp_assoc_add_peer(asoc, &addr, GFP_ATOMIC, SCTP_UNCONFIRMED);
3012 		if (!peer)
3013 			return SCTP_ERROR_RSRC_LOW;
3014 
3015 		/* Start the heartbeat timer. */
3016 		if (!mod_timer(&peer->hb_timer, sctp_transport_timeout(peer)))
3017 			sctp_transport_hold(peer);
3018 		asoc->new_transport = peer;
3019 		break;
3020 	case SCTP_PARAM_DEL_IP:
3021 		/* ADDIP 4.3 D7) If a request is received to delete the
3022 		 * last remaining IP address of a peer endpoint, the receiver
3023 		 * MUST send an Error Cause TLV with the error cause set to the
3024 		 * new error code 'Request to Delete Last Remaining IP Address'.
3025 		 */
3026 		if (asoc->peer.transport_count == 1)
3027 			return SCTP_ERROR_DEL_LAST_IP;
3028 
3029 		/* ADDIP 4.3 D8) If a request is received to delete an IP
3030 		 * address which is also the source address of the IP packet
3031 		 * which contained the ASCONF chunk, the receiver MUST reject
3032 		 * this request. To reject the request the receiver MUST send
3033 		 * an Error Cause TLV set to the new error code 'Request to
3034 		 * Delete Source IP Address'
3035 		 */
3036 		if (sctp_cmp_addr_exact(&asconf->source, &addr))
3037 			return SCTP_ERROR_DEL_SRC_IP;
3038 
3039 		/* Section 4.2.2
3040 		 * If the address 0.0.0.0 or ::0 is provided, all
3041 		 * addresses of the peer except	the source address of the
3042 		 * packet MUST be deleted.
3043 		 */
3044 		if (af->is_any(&addr)) {
3045 			sctp_assoc_set_primary(asoc, asconf->transport);
3046 			sctp_assoc_del_nonprimary_peers(asoc,
3047 							asconf->transport);
3048 		} else
3049 			sctp_assoc_del_peer(asoc, &addr);
3050 		break;
3051 	case SCTP_PARAM_SET_PRIMARY:
3052 		/* ADDIP Section 4.2.4
3053 		 * If the address 0.0.0.0 or ::0 is provided, the receiver
3054 		 * MAY mark the source address of the packet as its
3055 		 * primary.
3056 		 */
3057 		if (af->is_any(&addr))
3058 			memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));
3059 
3060 		peer = sctp_assoc_lookup_paddr(asoc, &addr);
3061 		if (!peer)
3062 			return SCTP_ERROR_DNS_FAILED;
3063 
3064 		sctp_assoc_set_primary(asoc, peer);
3065 		break;
3066 	}
3067 
3068 	return SCTP_ERROR_NO_ERROR;
3069 }
3070 
3071 /* Verify the ASCONF packet before we process it.  */
sctp_verify_asconf(const struct sctp_association * asoc,struct sctp_paramhdr * param_hdr,void * chunk_end,struct sctp_paramhdr ** errp)3072 int sctp_verify_asconf(const struct sctp_association *asoc,
3073 		       struct sctp_paramhdr *param_hdr, void *chunk_end,
3074 		       struct sctp_paramhdr **errp) {
3075 	sctp_addip_param_t *asconf_param;
3076 	union sctp_params param;
3077 	int length, plen;
3078 
3079 	param.v = (sctp_paramhdr_t *) param_hdr;
3080 	while (param.v <= chunk_end - sizeof(sctp_paramhdr_t)) {
3081 		length = ntohs(param.p->length);
3082 		*errp = param.p;
3083 
3084 		if (param.v > chunk_end - length ||
3085 		    length < sizeof(sctp_paramhdr_t))
3086 			return 0;
3087 
3088 		switch (param.p->type) {
3089 		case SCTP_PARAM_ADD_IP:
3090 		case SCTP_PARAM_DEL_IP:
3091 		case SCTP_PARAM_SET_PRIMARY:
3092 			asconf_param = (sctp_addip_param_t *)param.v;
3093 			plen = ntohs(asconf_param->param_hdr.length);
3094 			if (plen < sizeof(sctp_addip_param_t) +
3095 			    sizeof(sctp_paramhdr_t))
3096 				return 0;
3097 			break;
3098 		case SCTP_PARAM_SUCCESS_REPORT:
3099 		case SCTP_PARAM_ADAPTATION_LAYER_IND:
3100 			if (length != sizeof(sctp_addip_param_t))
3101 				return 0;
3102 
3103 			break;
3104 		default:
3105 			break;
3106 		}
3107 
3108 		param.v += WORD_ROUND(length);
3109 	}
3110 
3111 	if (param.v != chunk_end)
3112 		return 0;
3113 
3114 	return 1;
3115 }
3116 
3117 /* Process an incoming ASCONF chunk with the next expected serial no. and
3118  * return an ASCONF_ACK chunk to be sent in response.
3119  */
sctp_process_asconf(struct sctp_association * asoc,struct sctp_chunk * asconf)3120 struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
3121 				       struct sctp_chunk *asconf)
3122 {
3123 	sctp_addiphdr_t		*hdr;
3124 	union sctp_addr_param	*addr_param;
3125 	sctp_addip_param_t	*asconf_param;
3126 	struct sctp_chunk	*asconf_ack;
3127 
3128 	__be16	err_code;
3129 	int	length = 0;
3130 	int	chunk_len;
3131 	__u32	serial;
3132 	int	all_param_pass = 1;
3133 
3134 	chunk_len = ntohs(asconf->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
3135 	hdr = (sctp_addiphdr_t *)asconf->skb->data;
3136 	serial = ntohl(hdr->serial);
3137 
3138 	/* Skip the addiphdr and store a pointer to address parameter.  */
3139 	length = sizeof(sctp_addiphdr_t);
3140 	addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3141 	chunk_len -= length;
3142 
3143 	/* Skip the address parameter and store a pointer to the first
3144 	 * asconf parameter.
3145 	 */
3146 	length = ntohs(addr_param->p.length);
3147 	asconf_param = (void *)addr_param + length;
3148 	chunk_len -= length;
3149 
3150 	/* create an ASCONF_ACK chunk.
3151 	 * Based on the definitions of parameters, we know that the size of
3152 	 * ASCONF_ACK parameters are less than or equal to the fourfold of ASCONF
3153 	 * parameters.
3154 	 */
3155 	asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 4);
3156 	if (!asconf_ack)
3157 		goto done;
3158 
3159 	/* Process the TLVs contained within the ASCONF chunk. */
3160 	while (chunk_len > 0) {
3161 		err_code = sctp_process_asconf_param(asoc, asconf,
3162 						     asconf_param);
3163 		/* ADDIP 4.1 A7)
3164 		 * If an error response is received for a TLV parameter,
3165 		 * all TLVs with no response before the failed TLV are
3166 		 * considered successful if not reported.  All TLVs after
3167 		 * the failed response are considered unsuccessful unless
3168 		 * a specific success indication is present for the parameter.
3169 		 */
3170 		if (SCTP_ERROR_NO_ERROR != err_code)
3171 			all_param_pass = 0;
3172 
3173 		if (!all_param_pass)
3174 			sctp_add_asconf_response(asconf_ack,
3175 						 asconf_param->crr_id, err_code,
3176 						 asconf_param);
3177 
3178 		/* ADDIP 4.3 D11) When an endpoint receiving an ASCONF to add
3179 		 * an IP address sends an 'Out of Resource' in its response, it
3180 		 * MUST also fail any subsequent add or delete requests bundled
3181 		 * in the ASCONF.
3182 		 */
3183 		if (SCTP_ERROR_RSRC_LOW == err_code)
3184 			goto done;
3185 
3186 		/* Move to the next ASCONF param. */
3187 		length = ntohs(asconf_param->param_hdr.length);
3188 		asconf_param = (void *)asconf_param + length;
3189 		chunk_len -= length;
3190 	}
3191 
3192 done:
3193 	asoc->peer.addip_serial++;
3194 
3195 	/* If we are sending a new ASCONF_ACK hold a reference to it in assoc
3196 	 * after freeing the reference to old asconf ack if any.
3197 	 */
3198 	if (asconf_ack) {
3199 		sctp_chunk_hold(asconf_ack);
3200 		list_add_tail(&asconf_ack->transmitted_list,
3201 			      &asoc->asconf_ack_list);
3202 	}
3203 
3204 	return asconf_ack;
3205 }
3206 
3207 /* Process a asconf parameter that is successfully acked. */
sctp_asconf_param_success(struct sctp_association * asoc,sctp_addip_param_t * asconf_param)3208 static void sctp_asconf_param_success(struct sctp_association *asoc,
3209 				     sctp_addip_param_t *asconf_param)
3210 {
3211 	struct sctp_af *af;
3212 	union sctp_addr	addr;
3213 	struct sctp_bind_addr *bp = &asoc->base.bind_addr;
3214 	union sctp_addr_param *addr_param;
3215 	struct sctp_transport *transport;
3216 	struct sctp_sockaddr_entry *saddr;
3217 
3218 	addr_param = (void *)asconf_param + sizeof(sctp_addip_param_t);
3219 
3220 	/* We have checked the packet before, so we do not check again.	*/
3221 	af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3222 	af->from_addr_param(&addr, addr_param, htons(bp->port), 0);
3223 
3224 	switch (asconf_param->param_hdr.type) {
3225 	case SCTP_PARAM_ADD_IP:
3226 		/* This is always done in BH context with a socket lock
3227 		 * held, so the list can not change.
3228 		 */
3229 		local_bh_disable();
3230 		list_for_each_entry(saddr, &bp->address_list, list) {
3231 			if (sctp_cmp_addr_exact(&saddr->a, &addr))
3232 				saddr->state = SCTP_ADDR_SRC;
3233 		}
3234 		local_bh_enable();
3235 		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3236 				transports) {
3237 			dst_release(transport->dst);
3238 			transport->dst = NULL;
3239 		}
3240 		break;
3241 	case SCTP_PARAM_DEL_IP:
3242 		local_bh_disable();
3243 		sctp_del_bind_addr(bp, &addr);
3244 		if (asoc->asconf_addr_del_pending != NULL &&
3245 		    sctp_cmp_addr_exact(asoc->asconf_addr_del_pending, &addr)) {
3246 			kfree(asoc->asconf_addr_del_pending);
3247 			asoc->asconf_addr_del_pending = NULL;
3248 		}
3249 		local_bh_enable();
3250 		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3251 				transports) {
3252 			dst_release(transport->dst);
3253 			transport->dst = NULL;
3254 		}
3255 		break;
3256 	default:
3257 		break;
3258 	}
3259 }
3260 
3261 /* Get the corresponding ASCONF response error code from the ASCONF_ACK chunk
3262  * for the given asconf parameter.  If there is no response for this parameter,
3263  * return the error code based on the third argument 'no_err'.
3264  * ADDIP 4.1
3265  * A7) If an error response is received for a TLV parameter, all TLVs with no
3266  * response before the failed TLV are considered successful if not reported.
3267  * All TLVs after the failed response are considered unsuccessful unless a
3268  * specific success indication is present for the parameter.
3269  */
sctp_get_asconf_response(struct sctp_chunk * asconf_ack,sctp_addip_param_t * asconf_param,int no_err)3270 static __be16 sctp_get_asconf_response(struct sctp_chunk *asconf_ack,
3271 				      sctp_addip_param_t *asconf_param,
3272 				      int no_err)
3273 {
3274 	sctp_addip_param_t	*asconf_ack_param;
3275 	sctp_errhdr_t		*err_param;
3276 	int			length;
3277 	int			asconf_ack_len;
3278 	__be16			err_code;
3279 
3280 	if (no_err)
3281 		err_code = SCTP_ERROR_NO_ERROR;
3282 	else
3283 		err_code = SCTP_ERROR_REQ_REFUSED;
3284 
3285 	asconf_ack_len = ntohs(asconf_ack->chunk_hdr->length) -
3286 			     sizeof(sctp_chunkhdr_t);
3287 
3288 	/* Skip the addiphdr from the asconf_ack chunk and store a pointer to
3289 	 * the first asconf_ack parameter.
3290 	 */
3291 	length = sizeof(sctp_addiphdr_t);
3292 	asconf_ack_param = (sctp_addip_param_t *)(asconf_ack->skb->data +
3293 						  length);
3294 	asconf_ack_len -= length;
3295 
3296 	while (asconf_ack_len > 0) {
3297 		if (asconf_ack_param->crr_id == asconf_param->crr_id) {
3298 			switch(asconf_ack_param->param_hdr.type) {
3299 			case SCTP_PARAM_SUCCESS_REPORT:
3300 				return SCTP_ERROR_NO_ERROR;
3301 			case SCTP_PARAM_ERR_CAUSE:
3302 				length = sizeof(sctp_addip_param_t);
3303 				err_param = (void *)asconf_ack_param + length;
3304 				asconf_ack_len -= length;
3305 				if (asconf_ack_len > 0)
3306 					return err_param->cause;
3307 				else
3308 					return SCTP_ERROR_INV_PARAM;
3309 				break;
3310 			default:
3311 				return SCTP_ERROR_INV_PARAM;
3312 			}
3313 		}
3314 
3315 		length = ntohs(asconf_ack_param->param_hdr.length);
3316 		asconf_ack_param = (void *)asconf_ack_param + length;
3317 		asconf_ack_len -= length;
3318 	}
3319 
3320 	return err_code;
3321 }
3322 
3323 /* Process an incoming ASCONF_ACK chunk against the cached last ASCONF chunk. */
sctp_process_asconf_ack(struct sctp_association * asoc,struct sctp_chunk * asconf_ack)3324 int sctp_process_asconf_ack(struct sctp_association *asoc,
3325 			    struct sctp_chunk *asconf_ack)
3326 {
3327 	struct sctp_chunk	*asconf = asoc->addip_last_asconf;
3328 	union sctp_addr_param	*addr_param;
3329 	sctp_addip_param_t	*asconf_param;
3330 	int	length = 0;
3331 	int	asconf_len = asconf->skb->len;
3332 	int	all_param_pass = 0;
3333 	int	no_err = 1;
3334 	int	retval = 0;
3335 	__be16	err_code = SCTP_ERROR_NO_ERROR;
3336 
3337 	/* Skip the chunkhdr and addiphdr from the last asconf sent and store
3338 	 * a pointer to address parameter.
3339 	 */
3340 	length = sizeof(sctp_addip_chunk_t);
3341 	addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3342 	asconf_len -= length;
3343 
3344 	/* Skip the address parameter in the last asconf sent and store a
3345 	 * pointer to the first asconf parameter.
3346 	 */
3347 	length = ntohs(addr_param->p.length);
3348 	asconf_param = (void *)addr_param + length;
3349 	asconf_len -= length;
3350 
3351 	/* ADDIP 4.1
3352 	 * A8) If there is no response(s) to specific TLV parameter(s), and no
3353 	 * failures are indicated, then all request(s) are considered
3354 	 * successful.
3355 	 */
3356 	if (asconf_ack->skb->len == sizeof(sctp_addiphdr_t))
3357 		all_param_pass = 1;
3358 
3359 	/* Process the TLVs contained in the last sent ASCONF chunk. */
3360 	while (asconf_len > 0) {
3361 		if (all_param_pass)
3362 			err_code = SCTP_ERROR_NO_ERROR;
3363 		else {
3364 			err_code = sctp_get_asconf_response(asconf_ack,
3365 							    asconf_param,
3366 							    no_err);
3367 			if (no_err && (SCTP_ERROR_NO_ERROR != err_code))
3368 				no_err = 0;
3369 		}
3370 
3371 		switch (err_code) {
3372 		case SCTP_ERROR_NO_ERROR:
3373 			sctp_asconf_param_success(asoc, asconf_param);
3374 			break;
3375 
3376 		case SCTP_ERROR_RSRC_LOW:
3377 			retval = 1;
3378 			break;
3379 
3380 		case SCTP_ERROR_UNKNOWN_PARAM:
3381 			/* Disable sending this type of asconf parameter in
3382 			 * future.
3383 			 */
3384 			asoc->peer.addip_disabled_mask |=
3385 				asconf_param->param_hdr.type;
3386 			break;
3387 
3388 		case SCTP_ERROR_REQ_REFUSED:
3389 		case SCTP_ERROR_DEL_LAST_IP:
3390 		case SCTP_ERROR_DEL_SRC_IP:
3391 		default:
3392 			 break;
3393 		}
3394 
3395 		/* Skip the processed asconf parameter and move to the next
3396 		 * one.
3397 		 */
3398 		length = ntohs(asconf_param->param_hdr.length);
3399 		asconf_param = (void *)asconf_param + length;
3400 		asconf_len -= length;
3401 	}
3402 
3403 	if (no_err && asoc->src_out_of_asoc_ok) {
3404 		asoc->src_out_of_asoc_ok = 0;
3405 		sctp_transport_immediate_rtx(asoc->peer.primary_path);
3406 	}
3407 
3408 	/* Free the cached last sent asconf chunk. */
3409 	list_del_init(&asconf->transmitted_list);
3410 	sctp_chunk_free(asconf);
3411 	asoc->addip_last_asconf = NULL;
3412 
3413 	return retval;
3414 }
3415 
3416 /* Make a FWD TSN chunk. */
sctp_make_fwdtsn(const struct sctp_association * asoc,__u32 new_cum_tsn,size_t nstreams,struct sctp_fwdtsn_skip * skiplist)3417 struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
3418 				    __u32 new_cum_tsn, size_t nstreams,
3419 				    struct sctp_fwdtsn_skip *skiplist)
3420 {
3421 	struct sctp_chunk *retval = NULL;
3422 	struct sctp_fwdtsn_hdr ftsn_hdr;
3423 	struct sctp_fwdtsn_skip skip;
3424 	size_t hint;
3425 	int i;
3426 
3427 	hint = (nstreams + 1) * sizeof(__u32);
3428 
3429 	retval = sctp_make_chunk(asoc, SCTP_CID_FWD_TSN, 0, hint);
3430 
3431 	if (!retval)
3432 		return NULL;
3433 
3434 	ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
3435 	retval->subh.fwdtsn_hdr =
3436 		sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
3437 
3438 	for (i = 0; i < nstreams; i++) {
3439 		skip.stream = skiplist[i].stream;
3440 		skip.ssn = skiplist[i].ssn;
3441 		sctp_addto_chunk(retval, sizeof(skip), &skip);
3442 	}
3443 
3444 	return retval;
3445 }
3446