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TOMOYO Linux Cross Reference
Linux/net/sctp/sm_make_chunk.c

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  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 #include <linux/types.h>
 54 #include <linux/kernel.h>
 55 #include <linux/ip.h>
 56 #include <linux/ipv6.h>
 57 #include <linux/net.h>
 58 #include <linux/inet.h>
 59 #include <linux/scatterlist.h>
 60 #include <linux/crypto.h>
 61 #include <net/sock.h>
 62 
 63 #include <linux/skbuff.h>
 64 #include <linux/random.h>       /* for get_random_bytes */
 65 #include <net/sctp/sctp.h>
 66 #include <net/sctp/sm.h>
 67 
 68 SCTP_STATIC
 69 struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc,
 70                                    __u8 type, __u8 flags, int paylen);
 71 static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
 72                                         const struct sctp_association *asoc,
 73                                         const struct sctp_chunk *init_chunk,
 74                                         int *cookie_len,
 75                                         const __u8 *raw_addrs, int addrs_len);
 76 static int sctp_process_param(struct sctp_association *asoc,
 77                               union sctp_params param,
 78                               const union sctp_addr *peer_addr,
 79                               gfp_t gfp);
 80 static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
 81                               const void *data);
 82 
 83 /* What was the inbound interface for this chunk? */
 84 int sctp_chunk_iif(const struct sctp_chunk *chunk)
 85 {
 86         struct sctp_af *af;
 87         int iif = 0;
 88 
 89         af = sctp_get_af_specific(ipver2af(ip_hdr(chunk->skb)->version));
 90         if (af)
 91                 iif = af->skb_iif(chunk->skb);
 92 
 93         return iif;
 94 }
 95 
 96 /* RFC 2960 3.3.2 Initiation (INIT) (1)
 97  *
 98  * Note 2: The ECN capable field is reserved for future use of
 99  * Explicit Congestion Notification.
100  */
101 static const struct sctp_paramhdr ecap_param = {
102         SCTP_PARAM_ECN_CAPABLE,
103         cpu_to_be16(sizeof(struct sctp_paramhdr)),
104 };
105 static const struct sctp_paramhdr prsctp_param = {
106         SCTP_PARAM_FWD_TSN_SUPPORT,
107         cpu_to_be16(sizeof(struct sctp_paramhdr)),
108 };
109 
110 /* A helper to initialize an op error inside a
111  * provided chunk, as most cause codes will be embedded inside an
112  * abort chunk.
113  */
114 void  sctp_init_cause(struct sctp_chunk *chunk, __be16 cause_code,
115                       size_t paylen)
116 {
117         sctp_errhdr_t err;
118         __u16 len;
119 
120         /* Cause code constants are now defined in network order.  */
121         err.cause = cause_code;
122         len = sizeof(sctp_errhdr_t) + paylen;
123         err.length  = htons(len);
124         chunk->subh.err_hdr = sctp_addto_chunk(chunk, sizeof(sctp_errhdr_t), &err);
125 }
126 
127 /* A helper to initialize an op error inside a
128  * provided chunk, as most cause codes will be embedded inside an
129  * abort chunk.  Differs from sctp_init_cause in that it won't oops
130  * if there isn't enough space in the op error chunk
131  */
132 int sctp_init_cause_fixed(struct sctp_chunk *chunk, __be16 cause_code,
133                       size_t paylen)
134 {
135         sctp_errhdr_t err;
136         __u16 len;
137 
138         /* Cause code constants are now defined in network order.  */
139         err.cause = cause_code;
140         len = sizeof(sctp_errhdr_t) + paylen;
141         err.length  = htons(len);
142 
143         if (skb_tailroom(chunk->skb) < len)
144                 return -ENOSPC;
145         chunk->subh.err_hdr = sctp_addto_chunk_fixed(chunk,
146                                                      sizeof(sctp_errhdr_t),
147                                                      &err);
148         return 0;
149 }
150 /* 3.3.2 Initiation (INIT) (1)
151  *
152  * This chunk is used to initiate a SCTP association between two
153  * endpoints. The format of the INIT chunk is shown below:
154  *
155  *     0                   1                   2                   3
156  *     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
157  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
158  *    |   Type = 1    |  Chunk Flags  |      Chunk Length             |
159  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
160  *    |                         Initiate Tag                          |
161  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
162  *    |           Advertised Receiver Window Credit (a_rwnd)          |
163  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
164  *    |  Number of Outbound Streams   |  Number of Inbound Streams    |
165  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
166  *    |                          Initial TSN                          |
167  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
168  *    \                                                               \
169  *    /              Optional/Variable-Length Parameters              /
170  *    \                                                               \
171  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
172  *
173  *
174  * The INIT chunk contains the following parameters. Unless otherwise
175  * noted, each parameter MUST only be included once in the INIT chunk.
176  *
177  * Fixed Parameters                     Status
178  * ----------------------------------------------
179  * Initiate Tag                        Mandatory
180  * Advertised Receiver Window Credit   Mandatory
181  * Number of Outbound Streams          Mandatory
182  * Number of Inbound Streams           Mandatory
183  * Initial TSN                         Mandatory
184  *
185  * Variable Parameters                  Status     Type Value
186  * -------------------------------------------------------------
187  * IPv4 Address (Note 1)               Optional    5
188  * IPv6 Address (Note 1)               Optional    6
189  * Cookie Preservative                 Optional    9
190  * Reserved for ECN Capable (Note 2)   Optional    32768 (0x8000)
191  * Host Name Address (Note 3)          Optional    11
192  * Supported Address Types (Note 4)    Optional    12
193  */
194 struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc,
195                              const struct sctp_bind_addr *bp,
196                              gfp_t gfp, int vparam_len)
197 {
198         sctp_inithdr_t init;
199         union sctp_params addrs;
200         size_t chunksize;
201         struct sctp_chunk *retval = NULL;
202         int num_types, addrs_len = 0;
203         struct sctp_sock *sp;
204         sctp_supported_addrs_param_t sat;
205         __be16 types[2];
206         sctp_adaptation_ind_param_t aiparam;
207         sctp_supported_ext_param_t ext_param;
208         int num_ext = 0;
209         __u8 extensions[3];
210         sctp_paramhdr_t *auth_chunks = NULL,
211                         *auth_hmacs = NULL;
212 
213         /* RFC 2960 3.3.2 Initiation (INIT) (1)
214          *
215          * Note 1: The INIT chunks can contain multiple addresses that
216          * can be IPv4 and/or IPv6 in any combination.
217          */
218         retval = NULL;
219 
220         /* Convert the provided bind address list to raw format. */
221         addrs = sctp_bind_addrs_to_raw(bp, &addrs_len, gfp);
222 
223         init.init_tag              = htonl(asoc->c.my_vtag);
224         init.a_rwnd                = htonl(asoc->rwnd);
225         init.num_outbound_streams  = htons(asoc->c.sinit_num_ostreams);
226         init.num_inbound_streams   = htons(asoc->c.sinit_max_instreams);
227         init.initial_tsn           = htonl(asoc->c.initial_tsn);
228 
229         /* How many address types are needed? */
230         sp = sctp_sk(asoc->base.sk);
231         num_types = sp->pf->supported_addrs(sp, types);
232 
233         chunksize = sizeof(init) + addrs_len;
234         chunksize += WORD_ROUND(SCTP_SAT_LEN(num_types));
235         chunksize += sizeof(ecap_param);
236 
237         if (sctp_prsctp_enable)
238                 chunksize += sizeof(prsctp_param);
239 
240         /* ADDIP: Section 4.2.7:
241          *  An implementation supporting this extension [ADDIP] MUST list
242          *  the ASCONF,the ASCONF-ACK, and the AUTH  chunks in its INIT and
243          *  INIT-ACK parameters.
244          */
245         if (sctp_addip_enable) {
246                 extensions[num_ext] = SCTP_CID_ASCONF;
247                 extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
248                 num_ext += 2;
249         }
250 
251         if (sp->adaptation_ind)
252                 chunksize += sizeof(aiparam);
253 
254         chunksize += vparam_len;
255 
256         /* Account for AUTH related parameters */
257         if (sctp_auth_enable) {
258                 /* Add random parameter length*/
259                 chunksize += sizeof(asoc->c.auth_random);
260 
261                 /* Add HMACS parameter length if any were defined */
262                 auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
263                 if (auth_hmacs->length)
264                         chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
265                 else
266                         auth_hmacs = NULL;
267 
268                 /* Add CHUNKS parameter length */
269                 auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
270                 if (auth_chunks->length)
271                         chunksize += WORD_ROUND(ntohs(auth_chunks->length));
272                 else
273                         auth_chunks = NULL;
274 
275                 extensions[num_ext] = SCTP_CID_AUTH;
276                 num_ext += 1;
277         }
278 
279         /* If we have any extensions to report, account for that */
280         if (num_ext)
281                 chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) +
282                                         num_ext);
283 
284         /* RFC 2960 3.3.2 Initiation (INIT) (1)
285          *
286          * Note 3: An INIT chunk MUST NOT contain more than one Host
287          * Name address parameter. Moreover, the sender of the INIT
288          * MUST NOT combine any other address types with the Host Name
289          * address in the INIT. The receiver of INIT MUST ignore any
290          * other address types if the Host Name address parameter is
291          * present in the received INIT chunk.
292          *
293          * PLEASE DO NOT FIXME [This version does not support Host Name.]
294          */
295 
296         retval = sctp_make_chunk(asoc, SCTP_CID_INIT, 0, chunksize);
297         if (!retval)
298                 goto nodata;
299 
300         retval->subh.init_hdr =
301                 sctp_addto_chunk(retval, sizeof(init), &init);
302         retval->param_hdr.v =
303                 sctp_addto_chunk(retval, addrs_len, addrs.v);
304 
305         /* RFC 2960 3.3.2 Initiation (INIT) (1)
306          *
307          * Note 4: This parameter, when present, specifies all the
308          * address types the sending endpoint can support. The absence
309          * of this parameter indicates that the sending endpoint can
310          * support any address type.
311          */
312         sat.param_hdr.type = SCTP_PARAM_SUPPORTED_ADDRESS_TYPES;
313         sat.param_hdr.length = htons(SCTP_SAT_LEN(num_types));
314         sctp_addto_chunk(retval, sizeof(sat), &sat);
315         sctp_addto_chunk(retval, num_types * sizeof(__u16), &types);
316 
317         sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
318 
319         /* Add the supported extensions parameter.  Be nice and add this
320          * fist before addiding the parameters for the extensions themselves
321          */
322         if (num_ext) {
323                 ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
324                 ext_param.param_hdr.length =
325                             htons(sizeof(sctp_supported_ext_param_t) + num_ext);
326                 sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
327                                 &ext_param);
328                 sctp_addto_param(retval, num_ext, extensions);
329         }
330 
331         if (sctp_prsctp_enable)
332                 sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
333 
334         if (sp->adaptation_ind) {
335                 aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
336                 aiparam.param_hdr.length = htons(sizeof(aiparam));
337                 aiparam.adaptation_ind = htonl(sp->adaptation_ind);
338                 sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
339         }
340 
341         /* Add SCTP-AUTH chunks to the parameter list */
342         if (sctp_auth_enable) {
343                 sctp_addto_chunk(retval, sizeof(asoc->c.auth_random),
344                                  asoc->c.auth_random);
345                 if (auth_hmacs)
346                         sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
347                                         auth_hmacs);
348                 if (auth_chunks)
349                         sctp_addto_chunk(retval, ntohs(auth_chunks->length),
350                                         auth_chunks);
351         }
352 nodata:
353         kfree(addrs.v);
354         return retval;
355 }
356 
357 struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc,
358                                  const struct sctp_chunk *chunk,
359                                  gfp_t gfp, int unkparam_len)
360 {
361         sctp_inithdr_t initack;
362         struct sctp_chunk *retval;
363         union sctp_params addrs;
364         struct sctp_sock *sp;
365         int addrs_len;
366         sctp_cookie_param_t *cookie;
367         int cookie_len;
368         size_t chunksize;
369         sctp_adaptation_ind_param_t aiparam;
370         sctp_supported_ext_param_t ext_param;
371         int num_ext = 0;
372         __u8 extensions[3];
373         sctp_paramhdr_t *auth_chunks = NULL,
374                         *auth_hmacs = NULL,
375                         *auth_random = NULL;
376 
377         retval = NULL;
378 
379         /* Note: there may be no addresses to embed. */
380         addrs = sctp_bind_addrs_to_raw(&asoc->base.bind_addr, &addrs_len, gfp);
381 
382         initack.init_tag                = htonl(asoc->c.my_vtag);
383         initack.a_rwnd                  = htonl(asoc->rwnd);
384         initack.num_outbound_streams    = htons(asoc->c.sinit_num_ostreams);
385         initack.num_inbound_streams     = htons(asoc->c.sinit_max_instreams);
386         initack.initial_tsn             = htonl(asoc->c.initial_tsn);
387 
388         /* FIXME:  We really ought to build the cookie right
389          * into the packet instead of allocating more fresh memory.
390          */
391         cookie = sctp_pack_cookie(asoc->ep, asoc, chunk, &cookie_len,
392                                   addrs.v, addrs_len);
393         if (!cookie)
394                 goto nomem_cookie;
395 
396         /* Calculate the total size of allocation, include the reserved
397          * space for reporting unknown parameters if it is specified.
398          */
399         sp = sctp_sk(asoc->base.sk);
400         chunksize = sizeof(initack) + addrs_len + cookie_len + unkparam_len;
401 
402         /* Tell peer that we'll do ECN only if peer advertised such cap.  */
403         if (asoc->peer.ecn_capable)
404                 chunksize += sizeof(ecap_param);
405 
406         if (asoc->peer.prsctp_capable)
407                 chunksize += sizeof(prsctp_param);
408 
409         if (asoc->peer.asconf_capable) {
410                 extensions[num_ext] = SCTP_CID_ASCONF;
411                 extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
412                 num_ext += 2;
413         }
414 
415         if (sp->adaptation_ind)
416                 chunksize += sizeof(aiparam);
417 
418         if (asoc->peer.auth_capable) {
419                 auth_random = (sctp_paramhdr_t *)asoc->c.auth_random;
420                 chunksize += ntohs(auth_random->length);
421 
422                 auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
423                 if (auth_hmacs->length)
424                         chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
425                 else
426                         auth_hmacs = NULL;
427 
428                 auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
429                 if (auth_chunks->length)
430                         chunksize += WORD_ROUND(ntohs(auth_chunks->length));
431                 else
432                         auth_chunks = NULL;
433 
434                 extensions[num_ext] = SCTP_CID_AUTH;
435                 num_ext += 1;
436         }
437 
438         if (num_ext)
439                 chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) +
440                                         num_ext);
441 
442         /* Now allocate and fill out the chunk.  */
443         retval = sctp_make_chunk(asoc, SCTP_CID_INIT_ACK, 0, chunksize);
444         if (!retval)
445                 goto nomem_chunk;
446 
447         /* Per the advice in RFC 2960 6.4, send this reply to
448          * the source of the INIT packet.
449          */
450         retval->transport = chunk->transport;
451         retval->subh.init_hdr =
452                 sctp_addto_chunk(retval, sizeof(initack), &initack);
453         retval->param_hdr.v = sctp_addto_chunk(retval, addrs_len, addrs.v);
454         sctp_addto_chunk(retval, cookie_len, cookie);
455         if (asoc->peer.ecn_capable)
456                 sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
457         if (num_ext) {
458                 ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
459                 ext_param.param_hdr.length =
460                             htons(sizeof(sctp_supported_ext_param_t) + num_ext);
461                 sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
462                                  &ext_param);
463                 sctp_addto_param(retval, num_ext, extensions);
464         }
465         if (asoc->peer.prsctp_capable)
466                 sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
467 
468         if (sp->adaptation_ind) {
469                 aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
470                 aiparam.param_hdr.length = htons(sizeof(aiparam));
471                 aiparam.adaptation_ind = htonl(sp->adaptation_ind);
472                 sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
473         }
474 
475         if (asoc->peer.auth_capable) {
476                 sctp_addto_chunk(retval, ntohs(auth_random->length),
477                                  auth_random);
478                 if (auth_hmacs)
479                         sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
480                                         auth_hmacs);
481                 if (auth_chunks)
482                         sctp_addto_chunk(retval, ntohs(auth_chunks->length),
483                                         auth_chunks);
484         }
485 
486         /* We need to remove the const qualifier at this point.  */
487         retval->asoc = (struct sctp_association *) asoc;
488 
489         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
490          *
491          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
492          * HEARTBEAT ACK, * etc.) to the same destination transport
493          * address from which it received the DATA or control chunk
494          * to which it is replying.
495          *
496          * [INIT ACK back to where the INIT came from.]
497          */
498         if (chunk)
499                 retval->transport = chunk->transport;
500 
501 nomem_chunk:
502         kfree(cookie);
503 nomem_cookie:
504         kfree(addrs.v);
505         return retval;
506 }
507 
508 /* 3.3.11 Cookie Echo (COOKIE ECHO) (10):
509  *
510  * This chunk is used only during the initialization of an association.
511  * It is sent by the initiator of an association to its peer to complete
512  * the initialization process. This chunk MUST precede any DATA chunk
513  * sent within the association, but MAY be bundled with one or more DATA
514  * chunks in the same packet.
515  *
516  *      0                   1                   2                   3
517  *      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
518  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
519  *     |   Type = 10   |Chunk  Flags   |         Length                |
520  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
521  *     /                     Cookie                                    /
522  *     \                                                               \
523  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
524  *
525  * Chunk Flags: 8 bit
526  *
527  *   Set to zero on transmit and ignored on receipt.
528  *
529  * Length: 16 bits (unsigned integer)
530  *
531  *   Set to the size of the chunk in bytes, including the 4 bytes of
532  *   the chunk header and the size of the Cookie.
533  *
534  * Cookie: variable size
535  *
536  *   This field must contain the exact cookie received in the
537  *   State Cookie parameter from the previous INIT ACK.
538  *
539  *   An implementation SHOULD make the cookie as small as possible
540  *   to insure interoperability.
541  */
542 struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *asoc,
543                                     const struct sctp_chunk *chunk)
544 {
545         struct sctp_chunk *retval;
546         void *cookie;
547         int cookie_len;
548 
549         cookie = asoc->peer.cookie;
550         cookie_len = asoc->peer.cookie_len;
551 
552         /* Build a cookie echo chunk.  */
553         retval = sctp_make_chunk(asoc, SCTP_CID_COOKIE_ECHO, 0, cookie_len);
554         if (!retval)
555                 goto nodata;
556         retval->subh.cookie_hdr =
557                 sctp_addto_chunk(retval, cookie_len, cookie);
558 
559         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
560          *
561          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
562          * HEARTBEAT ACK, * etc.) to the same destination transport
563          * address from which it * received the DATA or control chunk
564          * to which it is replying.
565          *
566          * [COOKIE ECHO back to where the INIT ACK came from.]
567          */
568         if (chunk)
569                 retval->transport = chunk->transport;
570 
571 nodata:
572         return retval;
573 }
574 
575 /* 3.3.12 Cookie Acknowledgement (COOKIE ACK) (11):
576  *
577  * This chunk is used only during the initialization of an
578  * association.  It is used to acknowledge the receipt of a COOKIE
579  * ECHO chunk.  This chunk MUST precede any DATA or SACK chunk sent
580  * within the association, but MAY be bundled with one or more DATA
581  * chunks or SACK chunk in the same SCTP packet.
582  *
583  *      0                   1                   2                   3
584  *      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
585  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
586  *     |   Type = 11   |Chunk  Flags   |     Length = 4                |
587  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
588  *
589  * Chunk Flags: 8 bits
590  *
591  *   Set to zero on transmit and ignored on receipt.
592  */
593 struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *asoc,
594                                    const struct sctp_chunk *chunk)
595 {
596         struct sctp_chunk *retval;
597 
598         retval = sctp_make_chunk(asoc, SCTP_CID_COOKIE_ACK, 0, 0);
599 
600         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
601          *
602          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
603          * HEARTBEAT ACK, * etc.) to the same destination transport
604          * address from which it * received the DATA or control chunk
605          * to which it is replying.
606          *
607          * [COOKIE ACK back to where the COOKIE ECHO came from.]
608          */
609         if (retval && chunk)
610                 retval->transport = chunk->transport;
611 
612         return retval;
613 }
614 
615 /*
616  *  Appendix A: Explicit Congestion Notification:
617  *  CWR:
618  *
619  *  RFC 2481 details a specific bit for a sender to send in the header of
620  *  its next outbound TCP segment to indicate to its peer that it has
621  *  reduced its congestion window.  This is termed the CWR bit.  For
622  *  SCTP the same indication is made by including the CWR chunk.
623  *  This chunk contains one data element, i.e. the TSN number that
624  *  was sent in the ECNE chunk.  This element represents the lowest
625  *  TSN number in the datagram that was originally marked with the
626  *  CE bit.
627  *
628  *     0                   1                   2                   3
629  *     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
630  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
631  *    | Chunk Type=13 | Flags=00000000|    Chunk Length = 8           |
632  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
633  *    |                      Lowest TSN Number                        |
634  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
635  *
636  *     Note: The CWR is considered a Control chunk.
637  */
638 struct sctp_chunk *sctp_make_cwr(const struct sctp_association *asoc,
639                             const __u32 lowest_tsn,
640                             const struct sctp_chunk *chunk)
641 {
642         struct sctp_chunk *retval;
643         sctp_cwrhdr_t cwr;
644 
645         cwr.lowest_tsn = htonl(lowest_tsn);
646         retval = sctp_make_chunk(asoc, SCTP_CID_ECN_CWR, 0,
647                                  sizeof(sctp_cwrhdr_t));
648 
649         if (!retval)
650                 goto nodata;
651 
652         retval->subh.ecn_cwr_hdr =
653                 sctp_addto_chunk(retval, sizeof(cwr), &cwr);
654 
655         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
656          *
657          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
658          * HEARTBEAT ACK, * etc.) to the same destination transport
659          * address from which it * received the DATA or control chunk
660          * to which it is replying.
661          *
662          * [Report a reduced congestion window back to where the ECNE
663          * came from.]
664          */
665         if (chunk)
666                 retval->transport = chunk->transport;
667 
668 nodata:
669         return retval;
670 }
671 
672 /* Make an ECNE chunk.  This is a congestion experienced report.  */
673 struct sctp_chunk *sctp_make_ecne(const struct sctp_association *asoc,
674                              const __u32 lowest_tsn)
675 {
676         struct sctp_chunk *retval;
677         sctp_ecnehdr_t ecne;
678 
679         ecne.lowest_tsn = htonl(lowest_tsn);
680         retval = sctp_make_chunk(asoc, SCTP_CID_ECN_ECNE, 0,
681                                  sizeof(sctp_ecnehdr_t));
682         if (!retval)
683                 goto nodata;
684         retval->subh.ecne_hdr =
685                 sctp_addto_chunk(retval, sizeof(ecne), &ecne);
686 
687 nodata:
688         return retval;
689 }
690 
691 /* Make a DATA chunk for the given association from the provided
692  * parameters.  However, do not populate the data payload.
693  */
694 struct sctp_chunk *sctp_make_datafrag_empty(struct sctp_association *asoc,
695                                        const struct sctp_sndrcvinfo *sinfo,
696                                        int data_len, __u8 flags, __u16 ssn)
697 {
698         struct sctp_chunk *retval;
699         struct sctp_datahdr dp;
700         int chunk_len;
701 
702         /* We assign the TSN as LATE as possible, not here when
703          * creating the chunk.
704          */
705         dp.tsn = 0;
706         dp.stream = htons(sinfo->sinfo_stream);
707         dp.ppid   = sinfo->sinfo_ppid;
708 
709         /* Set the flags for an unordered send.  */
710         if (sinfo->sinfo_flags & SCTP_UNORDERED) {
711                 flags |= SCTP_DATA_UNORDERED;
712                 dp.ssn = 0;
713         } else
714                 dp.ssn = htons(ssn);
715 
716         chunk_len = sizeof(dp) + data_len;
717         retval = sctp_make_chunk(asoc, SCTP_CID_DATA, flags, chunk_len);
718         if (!retval)
719                 goto nodata;
720 
721         retval->subh.data_hdr = sctp_addto_chunk(retval, sizeof(dp), &dp);
722         memcpy(&retval->sinfo, sinfo, sizeof(struct sctp_sndrcvinfo));
723 
724 nodata:
725         return retval;
726 }
727 
728 /* Create a selective ackowledgement (SACK) for the given
729  * association.  This reports on which TSN's we've seen to date,
730  * including duplicates and gaps.
731  */
732 struct sctp_chunk *sctp_make_sack(const struct sctp_association *asoc)
733 {
734         struct sctp_chunk *retval;
735         struct sctp_sackhdr sack;
736         int len;
737         __u32 ctsn;
738         __u16 num_gabs, num_dup_tsns;
739         struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
740         struct sctp_gap_ack_block gabs[SCTP_MAX_GABS];
741 
742         memset(gabs, 0, sizeof(gabs));
743         ctsn = sctp_tsnmap_get_ctsn(map);
744         SCTP_DEBUG_PRINTK("sackCTSNAck sent:  0x%x.\n", ctsn);
745 
746         /* How much room is needed in the chunk? */
747         num_gabs = sctp_tsnmap_num_gabs(map, gabs);
748         num_dup_tsns = sctp_tsnmap_num_dups(map);
749 
750         /* Initialize the SACK header.  */
751         sack.cum_tsn_ack            = htonl(ctsn);
752         sack.a_rwnd                 = htonl(asoc->a_rwnd);
753         sack.num_gap_ack_blocks     = htons(num_gabs);
754         sack.num_dup_tsns           = htons(num_dup_tsns);
755 
756         len = sizeof(sack)
757                 + sizeof(struct sctp_gap_ack_block) * num_gabs
758                 + sizeof(__u32) * num_dup_tsns;
759 
760         /* Create the chunk.  */
761         retval = sctp_make_chunk(asoc, SCTP_CID_SACK, 0, len);
762         if (!retval)
763                 goto nodata;
764 
765         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
766          *
767          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
768          * HEARTBEAT ACK, etc.) to the same destination transport
769          * address from which it received the DATA or control chunk to
770          * which it is replying.  This rule should also be followed if
771          * the endpoint is bundling DATA chunks together with the
772          * reply chunk.
773          *
774          * However, when acknowledging multiple DATA chunks received
775          * in packets from different source addresses in a single
776          * SACK, the SACK chunk may be transmitted to one of the
777          * destination transport addresses from which the DATA or
778          * control chunks being acknowledged were received.
779          *
780          * [BUG:  We do not implement the following paragraph.
781          * Perhaps we should remember the last transport we used for a
782          * SACK and avoid that (if possible) if we have seen any
783          * duplicates. --piggy]
784          *
785          * When a receiver of a duplicate DATA chunk sends a SACK to a
786          * multi- homed endpoint it MAY be beneficial to vary the
787          * destination address and not use the source address of the
788          * DATA chunk.  The reason being that receiving a duplicate
789          * from a multi-homed endpoint might indicate that the return
790          * path (as specified in the source address of the DATA chunk)
791          * for the SACK is broken.
792          *
793          * [Send to the address from which we last received a DATA chunk.]
794          */
795         retval->transport = asoc->peer.last_data_from;
796 
797         retval->subh.sack_hdr =
798                 sctp_addto_chunk(retval, sizeof(sack), &sack);
799 
800         /* Add the gap ack block information.   */
801         if (num_gabs)
802                 sctp_addto_chunk(retval, sizeof(__u32) * num_gabs,
803                                  gabs);
804 
805         /* Add the duplicate TSN information.  */
806         if (num_dup_tsns)
807                 sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns,
808                                  sctp_tsnmap_get_dups(map));
809 
810 nodata:
811         return retval;
812 }
813 
814 /* Make a SHUTDOWN chunk. */
815 struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
816                                       const struct sctp_chunk *chunk)
817 {
818         struct sctp_chunk *retval;
819         sctp_shutdownhdr_t shut;
820         __u32 ctsn;
821 
822         ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
823         shut.cum_tsn_ack = htonl(ctsn);
824 
825         retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN, 0,
826                                  sizeof(sctp_shutdownhdr_t));
827         if (!retval)
828                 goto nodata;
829 
830         retval->subh.shutdown_hdr =
831                 sctp_addto_chunk(retval, sizeof(shut), &shut);
832 
833         if (chunk)
834                 retval->transport = chunk->transport;
835 nodata:
836         return retval;
837 }
838 
839 struct sctp_chunk *sctp_make_shutdown_ack(const struct sctp_association *asoc,
840                                      const struct sctp_chunk *chunk)
841 {
842         struct sctp_chunk *retval;
843 
844         retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN_ACK, 0, 0);
845 
846         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
847          *
848          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
849          * HEARTBEAT ACK, * etc.) to the same destination transport
850          * address from which it * received the DATA or control chunk
851          * to which it is replying.
852          *
853          * [ACK back to where the SHUTDOWN came from.]
854          */
855         if (retval && chunk)
856                 retval->transport = chunk->transport;
857 
858         return retval;
859 }
860 
861 struct sctp_chunk *sctp_make_shutdown_complete(
862         const struct sctp_association *asoc,
863         const struct sctp_chunk *chunk)
864 {
865         struct sctp_chunk *retval;
866         __u8 flags = 0;
867 
868         /* Set the T-bit if we have no association (vtag will be
869          * reflected)
870          */
871         flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;
872 
873         retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags, 0);
874 
875         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
876          *
877          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
878          * HEARTBEAT ACK, * etc.) to the same destination transport
879          * address from which it * received the DATA or control chunk
880          * to which it is replying.
881          *
882          * [Report SHUTDOWN COMPLETE back to where the SHUTDOWN ACK
883          * came from.]
884          */
885         if (retval && chunk)
886                 retval->transport = chunk->transport;
887 
888         return retval;
889 }
890 
891 /* Create an ABORT.  Note that we set the T bit if we have no
892  * association, except when responding to an INIT (sctpimpguide 2.41).
893  */
894 struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc,
895                               const struct sctp_chunk *chunk,
896                               const size_t hint)
897 {
898         struct sctp_chunk *retval;
899         __u8 flags = 0;
900 
901         /* Set the T-bit if we have no association and 'chunk' is not
902          * an INIT (vtag will be reflected).
903          */
904         if (!asoc) {
905                 if (chunk && chunk->chunk_hdr &&
906                     chunk->chunk_hdr->type == SCTP_CID_INIT)
907                         flags = 0;
908                 else
909                         flags = SCTP_CHUNK_FLAG_T;
910         }
911 
912         retval = sctp_make_chunk(asoc, SCTP_CID_ABORT, flags, hint);
913 
914         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
915          *
916          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
917          * HEARTBEAT ACK, * etc.) to the same destination transport
918          * address from which it * received the DATA or control chunk
919          * to which it is replying.
920          *
921          * [ABORT back to where the offender came from.]
922          */
923         if (retval && chunk)
924                 retval->transport = chunk->transport;
925 
926         return retval;
927 }
928 
929 /* Helper to create ABORT with a NO_USER_DATA error.  */
930 struct sctp_chunk *sctp_make_abort_no_data(
931         const struct sctp_association *asoc,
932         const struct sctp_chunk *chunk, __u32 tsn)
933 {
934         struct sctp_chunk *retval;
935         __be32 payload;
936 
937         retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t)
938                                  + sizeof(tsn));
939 
940         if (!retval)
941                 goto no_mem;
942 
943         /* Put the tsn back into network byte order.  */
944         payload = htonl(tsn);
945         sctp_init_cause(retval, SCTP_ERROR_NO_DATA, sizeof(payload));
946         sctp_addto_chunk(retval, sizeof(payload), (const void *)&payload);
947 
948         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
949          *
950          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
951          * HEARTBEAT ACK, * etc.) to the same destination transport
952          * address from which it * received the DATA or control chunk
953          * to which it is replying.
954          *
955          * [ABORT back to where the offender came from.]
956          */
957         if (chunk)
958                 retval->transport = chunk->transport;
959 
960 no_mem:
961         return retval;
962 }
963 
964 /* Helper to create ABORT with a SCTP_ERROR_USER_ABORT error.  */
965 struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *asoc,
966                                         const struct msghdr *msg,
967                                         size_t paylen)
968 {
969         struct sctp_chunk *retval;
970         void *payload = NULL;
971         int err;
972 
973         retval = sctp_make_abort(asoc, NULL, sizeof(sctp_errhdr_t) + paylen);
974         if (!retval)
975                 goto err_chunk;
976 
977         if (paylen) {
978                 /* Put the msg_iov together into payload.  */
979                 payload = kmalloc(paylen, GFP_KERNEL);
980                 if (!payload)
981                         goto err_payload;
982 
983                 err = memcpy_fromiovec(payload, msg->msg_iov, paylen);
984                 if (err < 0)
985                         goto err_copy;
986         }
987 
988         sctp_init_cause(retval, SCTP_ERROR_USER_ABORT, paylen);
989         sctp_addto_chunk(retval, paylen, payload);
990 
991         if (paylen)
992                 kfree(payload);
993 
994         return retval;
995 
996 err_copy:
997         kfree(payload);
998 err_payload:
999         sctp_chunk_free(retval);
1000         retval = NULL;
1001 err_chunk:
1002         return retval;
1003 }
1004 
1005 /* Append bytes to the end of a parameter.  Will panic if chunk is not big
1006  * enough.
1007  */
1008 static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
1009                               const void *data)
1010 {
1011         void *target;
1012         int chunklen = ntohs(chunk->chunk_hdr->length);
1013 
1014         target = skb_put(chunk->skb, len);
1015 
1016         memcpy(target, data, len);
1017 
1018         /* Adjust the chunk length field.  */
1019         chunk->chunk_hdr->length = htons(chunklen + len);
1020         chunk->chunk_end = skb_tail_pointer(chunk->skb);
1021 
1022         return target;
1023 }
1024 
1025 /* Make an ABORT chunk with a PROTOCOL VIOLATION cause code. */
1026 struct sctp_chunk *sctp_make_abort_violation(
1027         const struct sctp_association *asoc,
1028         const struct sctp_chunk *chunk,
1029         const __u8   *payload,
1030         const size_t paylen)
1031 {
1032         struct sctp_chunk  *retval;
1033         struct sctp_paramhdr phdr;
1034 
1035         retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t) + paylen
1036                                         + sizeof(sctp_paramhdr_t));
1037         if (!retval)
1038                 goto end;
1039 
1040         sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, paylen
1041                                         + sizeof(sctp_paramhdr_t));
1042 
1043         phdr.type = htons(chunk->chunk_hdr->type);
1044         phdr.length = chunk->chunk_hdr->length;
1045         sctp_addto_chunk(retval, paylen, payload);
1046         sctp_addto_param(retval, sizeof(sctp_paramhdr_t), &phdr);
1047 
1048 end:
1049         return retval;
1050 }
1051 
1052 struct sctp_chunk *sctp_make_violation_paramlen(
1053         const struct sctp_association *asoc,
1054         const struct sctp_chunk *chunk,
1055         struct sctp_paramhdr *param)
1056 {
1057         struct sctp_chunk *retval;
1058         static const char error[] = "The following parameter had invalid length:";
1059         size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t) +
1060                                 sizeof(sctp_paramhdr_t);
1061 
1062         retval = sctp_make_abort(asoc, chunk, payload_len);
1063         if (!retval)
1064                 goto nodata;
1065 
1066         sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION,
1067                         sizeof(error) + sizeof(sctp_paramhdr_t));
1068         sctp_addto_chunk(retval, sizeof(error), error);
1069         sctp_addto_param(retval, sizeof(sctp_paramhdr_t), param);
1070 
1071 nodata:
1072         return retval;
1073 }
1074 
1075 /* Make a HEARTBEAT chunk.  */
1076 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
1077                                   const struct sctp_transport *transport,
1078                                   const void *payload, const size_t paylen)
1079 {
1080         struct sctp_chunk *retval = sctp_make_chunk(asoc, SCTP_CID_HEARTBEAT,
1081                                                     0, paylen);
1082 
1083         if (!retval)
1084                 goto nodata;
1085 
1086         /* Cast away the 'const', as this is just telling the chunk
1087          * what transport it belongs to.
1088          */
1089         retval->transport = (struct sctp_transport *) transport;
1090         retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);
1091 
1092 nodata:
1093         return retval;
1094 }
1095 
1096 struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc,
1097                                       const struct sctp_chunk *chunk,
1098                                       const void *payload, const size_t paylen)
1099 {
1100         struct sctp_chunk *retval;
1101 
1102         retval  = sctp_make_chunk(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen);
1103         if (!retval)
1104                 goto nodata;
1105 
1106         retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);
1107 
1108         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
1109          *
1110          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1111          * HEARTBEAT ACK, * etc.) to the same destination transport
1112          * address from which it * received the DATA or control chunk
1113          * to which it is replying.
1114          *
1115          * [HBACK back to where the HEARTBEAT came from.]
1116          */
1117         if (chunk)
1118                 retval->transport = chunk->transport;
1119 
1120 nodata:
1121         return retval;
1122 }
1123 
1124 /* Create an Operation Error chunk with the specified space reserved.
1125  * This routine can be used for containing multiple causes in the chunk.
1126  */
1127 static struct sctp_chunk *sctp_make_op_error_space(
1128         const struct sctp_association *asoc,
1129         const struct sctp_chunk *chunk,
1130         size_t size)
1131 {
1132         struct sctp_chunk *retval;
1133 
1134         retval = sctp_make_chunk(asoc, SCTP_CID_ERROR, 0,
1135                                  sizeof(sctp_errhdr_t) + size);
1136         if (!retval)
1137                 goto nodata;
1138 
1139         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
1140          *
1141          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1142          * HEARTBEAT ACK, etc.) to the same destination transport
1143          * address from which it received the DATA or control chunk
1144          * to which it is replying.
1145          *
1146          */
1147         if (chunk)
1148                 retval->transport = chunk->transport;
1149 
1150 nodata:
1151         return retval;
1152 }
1153 
1154 /* Create an Operation Error chunk of a fixed size,
1155  * specifically, max(asoc->pathmtu, SCTP_DEFAULT_MAXSEGMENT)
1156  * This is a helper function to allocate an error chunk for
1157  * for those invalid parameter codes in which we may not want
1158  * to report all the errors, if the incomming chunk is large
1159  */
1160 static inline struct sctp_chunk *sctp_make_op_error_fixed(
1161         const struct sctp_association *asoc,
1162         const struct sctp_chunk *chunk)
1163 {
1164         size_t size = asoc ? asoc->pathmtu : 0;
1165 
1166         if (!size)
1167                 size = SCTP_DEFAULT_MAXSEGMENT;
1168 
1169         return sctp_make_op_error_space(asoc, chunk, size);
1170 }
1171 
1172 /* Create an Operation Error chunk.  */
1173 struct sctp_chunk *sctp_make_op_error(const struct sctp_association *asoc,
1174                                  const struct sctp_chunk *chunk,
1175                                  __be16 cause_code, const void *payload,
1176                                  size_t paylen)
1177 {
1178         struct sctp_chunk *retval;
1179 
1180         retval = sctp_make_op_error_space(asoc, chunk, paylen);
1181         if (!retval)
1182                 goto nodata;
1183 
1184         sctp_init_cause(retval, cause_code, paylen);
1185         sctp_addto_chunk(retval, paylen, payload);
1186 
1187 nodata:
1188         return retval;
1189 }
1190 
1191 struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc)
1192 {
1193         struct sctp_chunk *retval;
1194         struct sctp_hmac *hmac_desc;
1195         struct sctp_authhdr auth_hdr;
1196         __u8 *hmac;
1197 
1198         /* Get the first hmac that the peer told us to use */
1199         hmac_desc = sctp_auth_asoc_get_hmac(asoc);
1200         if (unlikely(!hmac_desc))
1201                 return NULL;
1202 
1203         retval = sctp_make_chunk(asoc, SCTP_CID_AUTH, 0,
1204                         hmac_desc->hmac_len + sizeof(sctp_authhdr_t));
1205         if (!retval)
1206                 return NULL;
1207 
1208         auth_hdr.hmac_id = htons(hmac_desc->hmac_id);
1209         auth_hdr.shkey_id = htons(asoc->active_key_id);
1210 
1211         retval->subh.auth_hdr = sctp_addto_chunk(retval, sizeof(sctp_authhdr_t),
1212                                                 &auth_hdr);
1213 
1214         hmac = skb_put(retval->skb, hmac_desc->hmac_len);
1215         memset(hmac, 0, hmac_desc->hmac_len);
1216 
1217         /* Adjust the chunk header to include the empty MAC */
1218         retval->chunk_hdr->length =
1219                 htons(ntohs(retval->chunk_hdr->length) + hmac_desc->hmac_len);
1220         retval->chunk_end = skb_tail_pointer(retval->skb);
1221 
1222         return retval;
1223 }
1224 
1225 
1226 /********************************************************************
1227  * 2nd Level Abstractions
1228  ********************************************************************/
1229 
1230 /* Turn an skb into a chunk.
1231  * FIXME: Eventually move the structure directly inside the skb->cb[].
1232  */
1233 struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
1234                             const struct sctp_association *asoc,
1235                             struct sock *sk)
1236 {
1237         struct sctp_chunk *retval;
1238 
1239         retval = kmem_cache_zalloc(sctp_chunk_cachep, GFP_ATOMIC);
1240 
1241         if (!retval)
1242                 goto nodata;
1243 
1244         if (!sk) {
1245                 SCTP_DEBUG_PRINTK("chunkifying skb %p w/o an sk\n", skb);
1246         }
1247 
1248         INIT_LIST_HEAD(&retval->list);
1249         retval->skb             = skb;
1250         retval->asoc            = (struct sctp_association *)asoc;
1251         retval->resent          = 0;
1252         retval->has_tsn         = 0;
1253         retval->has_ssn         = 0;
1254         retval->rtt_in_progress = 0;
1255         retval->sent_at         = 0;
1256         retval->singleton       = 1;
1257         retval->end_of_packet   = 0;
1258         retval->ecn_ce_done     = 0;
1259         retval->pdiscard        = 0;
1260 
1261         /* sctpimpguide-05.txt Section 2.8.2
1262          * M1) Each time a new DATA chunk is transmitted
1263          * set the 'TSN.Missing.Report' count for that TSN to 0. The
1264          * 'TSN.Missing.Report' count will be used to determine missing chunks
1265          * and when to fast retransmit.
1266          */
1267         retval->tsn_missing_report = 0;
1268         retval->tsn_gap_acked = 0;
1269         retval->fast_retransmit = SCTP_CAN_FRTX;
1270 
1271         /* If this is a fragmented message, track all fragments
1272          * of the message (for SEND_FAILED).
1273          */
1274         retval->msg = NULL;
1275 
1276         /* Polish the bead hole.  */
1277         INIT_LIST_HEAD(&retval->transmitted_list);
1278         INIT_LIST_HEAD(&retval->frag_list);
1279         SCTP_DBG_OBJCNT_INC(chunk);
1280         atomic_set(&retval->refcnt, 1);
1281 
1282 nodata:
1283         return retval;
1284 }
1285 
1286 /* Set chunk->source and dest based on the IP header in chunk->skb.  */
1287 void sctp_init_addrs(struct sctp_chunk *chunk, union sctp_addr *src,
1288                      union sctp_addr *dest)
1289 {
1290         memcpy(&chunk->source, src, sizeof(union sctp_addr));
1291         memcpy(&chunk->dest, dest, sizeof(union sctp_addr));
1292 }
1293 
1294 /* Extract the source address from a chunk.  */
1295 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk)
1296 {
1297         /* If we have a known transport, use that.  */
1298         if (chunk->transport) {
1299                 return &chunk->transport->ipaddr;
1300         } else {
1301                 /* Otherwise, extract it from the IP header.  */
1302                 return &chunk->source;
1303         }
1304 }
1305 
1306 /* Create a new chunk, setting the type and flags headers from the
1307  * arguments, reserving enough space for a 'paylen' byte payload.
1308  */
1309 SCTP_STATIC
1310 struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc,
1311                                    __u8 type, __u8 flags, int paylen)
1312 {
1313         struct sctp_chunk *retval;
1314         sctp_chunkhdr_t *chunk_hdr;
1315         struct sk_buff *skb;
1316         struct sock *sk;
1317 
1318         /* No need to allocate LL here, as this is only a chunk. */
1319         skb = alloc_skb(WORD_ROUND(sizeof(sctp_chunkhdr_t) + paylen),
1320                         GFP_ATOMIC);
1321         if (!skb)
1322                 goto nodata;
1323 
1324         /* Make room for the chunk header.  */
1325         chunk_hdr = (sctp_chunkhdr_t *)skb_put(skb, sizeof(sctp_chunkhdr_t));
1326         chunk_hdr->type   = type;
1327         chunk_hdr->flags  = flags;
1328         chunk_hdr->length = htons(sizeof(sctp_chunkhdr_t));
1329 
1330         sk = asoc ? asoc->base.sk : NULL;
1331         retval = sctp_chunkify(skb, asoc, sk);
1332         if (!retval) {
1333                 kfree_skb(skb);
1334                 goto nodata;
1335         }
1336 
1337         retval->chunk_hdr = chunk_hdr;
1338         retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(struct sctp_chunkhdr);
1339 
1340         /* Determine if the chunk needs to be authenticated */
1341         if (sctp_auth_send_cid(type, asoc))
1342                 retval->auth = 1;
1343 
1344         /* Set the skb to the belonging sock for accounting.  */
1345         skb->sk = sk;
1346 
1347         return retval;
1348 nodata:
1349         return NULL;
1350 }
1351 
1352 
1353 /* Release the memory occupied by a chunk.  */
1354 static void sctp_chunk_destroy(struct sctp_chunk *chunk)
1355 {
1356         BUG_ON(!list_empty(&chunk->list));
1357         list_del_init(&chunk->transmitted_list);
1358 
1359         consume_skb(chunk->skb);
1360         consume_skb(chunk->auth_chunk);
1361 
1362         SCTP_DBG_OBJCNT_DEC(chunk);
1363         kmem_cache_free(sctp_chunk_cachep, chunk);
1364 }
1365 
1366 /* Possibly, free the chunk.  */
1367 void sctp_chunk_free(struct sctp_chunk *chunk)
1368 {
1369         /* Release our reference on the message tracker. */
1370         if (chunk->msg)
1371                 sctp_datamsg_put(chunk->msg);
1372 
1373         sctp_chunk_put(chunk);
1374 }
1375 
1376 /* Grab a reference to the chunk. */
1377 void sctp_chunk_hold(struct sctp_chunk *ch)
1378 {
1379         atomic_inc(&ch->refcnt);
1380 }
1381 
1382 /* Release a reference to the chunk. */
1383 void sctp_chunk_put(struct sctp_chunk *ch)
1384 {
1385         if (atomic_dec_and_test(&ch->refcnt))
1386                 sctp_chunk_destroy(ch);
1387 }
1388 
1389 /* Append bytes to the end of a chunk.  Will panic if chunk is not big
1390  * enough.
1391  */
1392 void *sctp_addto_chunk(struct sctp_chunk *chunk, int len, const void *data)
1393 {
1394         void *target;
1395         void *padding;
1396         int chunklen = ntohs(chunk->chunk_hdr->length);
1397         int padlen = WORD_ROUND(chunklen) - chunklen;
1398 
1399         padding = skb_put(chunk->skb, padlen);
1400         target = skb_put(chunk->skb, len);
1401 
1402         memset(padding, 0, padlen);
1403         memcpy(target, data, len);
1404 
1405         /* Adjust the chunk length field.  */
1406         chunk->chunk_hdr->length = htons(chunklen + padlen + len);
1407         chunk->chunk_end = skb_tail_pointer(chunk->skb);
1408 
1409         return target;
1410 }
1411 
1412 /* Append bytes to the end of a chunk. Returns NULL if there isn't sufficient
1413  * space in the chunk
1414  */
1415 void *sctp_addto_chunk_fixed(struct sctp_chunk *chunk,
1416                              int len, const void *data)
1417 {
1418         if (skb_tailroom(chunk->skb) >= len)
1419                 return sctp_addto_chunk(chunk, len, data);
1420         else
1421                 return NULL;
1422 }
1423 
1424 /* Append bytes from user space to the end of a chunk.  Will panic if
1425  * chunk is not big enough.
1426  * Returns a kernel err value.
1427  */
1428 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int off, int len,
1429                           struct iovec *data)
1430 {
1431         __u8 *target;
1432         int err = 0;
1433 
1434         /* Make room in chunk for data.  */
1435         target = skb_put(chunk->skb, len);
1436 
1437         /* Copy data (whole iovec) into chunk */
1438         if ((err = memcpy_fromiovecend(target, data, off, len)))
1439                 goto out;
1440 
1441         /* Adjust the chunk length field.  */
1442         chunk->chunk_hdr->length =
1443                 htons(ntohs(chunk->chunk_hdr->length) + len);
1444         chunk->chunk_end = skb_tail_pointer(chunk->skb);
1445 
1446 out:
1447         return err;
1448 }
1449 
1450 /* Helper function to assign a TSN if needed.  This assumes that both
1451  * the data_hdr and association have already been assigned.
1452  */
1453 void sctp_chunk_assign_ssn(struct sctp_chunk *chunk)
1454 {
1455         struct sctp_datamsg *msg;
1456         struct sctp_chunk *lchunk;
1457         struct sctp_stream *stream;
1458         __u16 ssn;
1459         __u16 sid;
1460 
1461         if (chunk->has_ssn)
1462                 return;
1463 
1464         /* All fragments will be on the same stream */
1465         sid = ntohs(chunk->subh.data_hdr->stream);
1466         stream = &chunk->asoc->ssnmap->out;
1467 
1468         /* Now assign the sequence number to the entire message.
1469          * All fragments must have the same stream sequence number.
1470          */
1471         msg = chunk->msg;
1472         list_for_each_entry(lchunk, &msg->chunks, frag_list) {
1473                 if (lchunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
1474                         ssn = 0;
1475                 } else {
1476                         if (lchunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG)
1477                                 ssn = sctp_ssn_next(stream, sid);
1478                         else
1479                                 ssn = sctp_ssn_peek(stream, sid);
1480                 }
1481 
1482                 lchunk->subh.data_hdr->ssn = htons(ssn);
1483                 lchunk->has_ssn = 1;
1484         }
1485 }
1486 
1487 /* Helper function to assign a TSN if needed.  This assumes that both
1488  * the data_hdr and association have already been assigned.
1489  */
1490 void sctp_chunk_assign_tsn(struct sctp_chunk *chunk)
1491 {
1492         if (!chunk->has_tsn) {
1493                 /* This is the last possible instant to
1494                  * assign a TSN.
1495                  */
1496                 chunk->subh.data_hdr->tsn =
1497                         htonl(sctp_association_get_next_tsn(chunk->asoc));
1498                 chunk->has_tsn = 1;
1499         }
1500 }
1501 
1502 /* Create a CLOSED association to use with an incoming packet.  */
1503 struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *ep,
1504                                         struct sctp_chunk *chunk,
1505                                         gfp_t gfp)
1506 {
1507         struct sctp_association *asoc;
1508         struct sk_buff *skb;
1509         sctp_scope_t scope;
1510         struct sctp_af *af;
1511 
1512         /* Create the bare association.  */
1513         scope = sctp_scope(sctp_source(chunk));
1514         asoc = sctp_association_new(ep, ep->base.sk, scope, gfp);
1515         if (!asoc)
1516                 goto nodata;
1517         asoc->temp = 1;
1518         skb = chunk->skb;
1519         /* Create an entry for the source address of the packet.  */
1520         af = sctp_get_af_specific(ipver2af(ip_hdr(skb)->version));
1521         if (unlikely(!af))
1522                 goto fail;
1523         af->from_skb(&asoc->c.peer_addr, skb, 1);
1524 nodata:
1525         return asoc;
1526 
1527 fail:
1528         sctp_association_free(asoc);
1529         return NULL;
1530 }
1531 
1532 /* Build a cookie representing asoc.
1533  * This INCLUDES the param header needed to put the cookie in the INIT ACK.
1534  */
1535 static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
1536                                       const struct sctp_association *asoc,
1537                                       const struct sctp_chunk *init_chunk,
1538                                       int *cookie_len,
1539                                       const __u8 *raw_addrs, int addrs_len)
1540 {
1541         sctp_cookie_param_t *retval;
1542         struct sctp_signed_cookie *cookie;
1543         struct scatterlist sg;
1544         int headersize, bodysize;
1545         unsigned int keylen;
1546         char *key;
1547 
1548         /* Header size is static data prior to the actual cookie, including
1549          * any padding.
1550          */
1551         headersize = sizeof(sctp_paramhdr_t) +
1552                      (sizeof(struct sctp_signed_cookie) -
1553                       sizeof(struct sctp_cookie));
1554         bodysize = sizeof(struct sctp_cookie)
1555                 + ntohs(init_chunk->chunk_hdr->length) + addrs_len;
1556 
1557         /* Pad out the cookie to a multiple to make the signature
1558          * functions simpler to write.
1559          */
1560         if (bodysize % SCTP_COOKIE_MULTIPLE)
1561                 bodysize += SCTP_COOKIE_MULTIPLE
1562                         - (bodysize % SCTP_COOKIE_MULTIPLE);
1563         *cookie_len = headersize + bodysize;
1564 
1565         /* Clear this memory since we are sending this data structure
1566          * out on the network.
1567          */
1568         retval = kzalloc(*cookie_len, GFP_ATOMIC);
1569         if (!retval)
1570                 goto nodata;
1571 
1572         cookie = (struct sctp_signed_cookie *) retval->body;
1573 
1574         /* Set up the parameter header.  */
1575         retval->p.type = SCTP_PARAM_STATE_COOKIE;
1576         retval->p.length = htons(*cookie_len);
1577 
1578         /* Copy the cookie part of the association itself.  */
1579         cookie->c = asoc->c;
1580         /* Save the raw address list length in the cookie. */
1581         cookie->c.raw_addr_list_len = addrs_len;
1582 
1583         /* Remember PR-SCTP capability. */
1584         cookie->c.prsctp_capable = asoc->peer.prsctp_capable;
1585 
1586         /* Save adaptation indication in the cookie. */
1587         cookie->c.adaptation_ind = asoc->peer.adaptation_ind;
1588 
1589         /* Set an expiration time for the cookie.  */
1590         do_gettimeofday(&cookie->c.expiration);
1591         TIMEVAL_ADD(asoc->cookie_life, cookie->c.expiration);
1592 
1593         /* Copy the peer's init packet.  */
1594         memcpy(&cookie->c.peer_init[0], init_chunk->chunk_hdr,
1595                ntohs(init_chunk->chunk_hdr->length));
1596 
1597         /* Copy the raw local address list of the association. */
1598         memcpy((__u8 *)&cookie->c.peer_init[0] +
1599                ntohs(init_chunk->chunk_hdr->length), raw_addrs, addrs_len);
1600 
1601         if (sctp_sk(ep->base.sk)->hmac) {
1602                 struct hash_desc desc;
1603 
1604                 /* Sign the message.  */
1605                 sg_init_one(&sg, &cookie->c, bodysize);
1606                 keylen = SCTP_SECRET_SIZE;
1607                 key = (char *)ep->secret_key[ep->current_key];
1608                 desc.tfm = sctp_sk(ep->base.sk)->hmac;
1609                 desc.flags = 0;
1610 
1611                 if (crypto_hash_setkey(desc.tfm, key, keylen) ||
1612                     crypto_hash_digest(&desc, &sg, bodysize, cookie->signature))
1613                         goto free_cookie;
1614         }
1615 
1616         return retval;
1617 
1618 free_cookie:
1619         kfree(retval);
1620 nodata:
1621         *cookie_len = 0;
1622         return NULL;
1623 }
1624 
1625 /* Unpack the cookie from COOKIE ECHO chunk, recreating the association.  */
1626 struct sctp_association *sctp_unpack_cookie(
1627         const struct sctp_endpoint *ep,
1628         const struct sctp_association *asoc,
1629         struct sctp_chunk *chunk, gfp_t gfp,
1630         int *error, struct sctp_chunk **errp)
1631 {
1632         struct sctp_association *retval = NULL;
1633         struct sctp_signed_cookie *cookie;
1634         struct sctp_cookie *bear_cookie;
1635         int headersize, bodysize, fixed_size;
1636         __u8 *digest = ep->digest;
1637         struct scatterlist sg;
1638         unsigned int keylen, len;
1639         char *key;
1640         sctp_scope_t scope;
1641         struct sk_buff *skb = chunk->skb;
1642         struct timeval tv;
1643         struct hash_desc desc;
1644 
1645         /* Header size is static data prior to the actual cookie, including
1646          * any padding.
1647          */
1648         headersize = sizeof(sctp_chunkhdr_t) +
1649                      (sizeof(struct sctp_signed_cookie) -
1650                       sizeof(struct sctp_cookie));
1651         bodysize = ntohs(chunk->chunk_hdr->length) - headersize;
1652         fixed_size = headersize + sizeof(struct sctp_cookie);
1653 
1654         /* Verify that the chunk looks like it even has a cookie.
1655          * There must be enough room for our cookie and our peer's
1656          * INIT chunk.
1657          */
1658         len = ntohs(chunk->chunk_hdr->length);
1659         if (len < fixed_size + sizeof(struct sctp_chunkhdr))
1660                 goto malformed;
1661 
1662         /* Verify that the cookie has been padded out. */
1663         if (bodysize % SCTP_COOKIE_MULTIPLE)
1664                 goto malformed;
1665 
1666         /* Process the cookie.  */
1667         cookie = chunk->subh.cookie_hdr;
1668         bear_cookie = &cookie->c;
1669 
1670         if (!sctp_sk(ep->base.sk)->hmac)
1671                 goto no_hmac;
1672 
1673         /* Check the signature.  */
1674         keylen = SCTP_SECRET_SIZE;
1675         sg_init_one(&sg, bear_cookie, bodysize);
1676         key = (char *)ep->secret_key[ep->current_key];
1677         desc.tfm = sctp_sk(ep->base.sk)->hmac;
1678         desc.flags = 0;
1679 
1680         memset(digest, 0x00, SCTP_SIGNATURE_SIZE);
1681         if (crypto_hash_setkey(desc.tfm, key, keylen) ||
1682             crypto_hash_digest(&desc, &sg, bodysize, digest)) {
1683                 *error = -SCTP_IERROR_NOMEM;
1684                 goto fail;
1685         }
1686 
1687         if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
1688                 /* Try the previous key. */
1689                 key = (char *)ep->secret_key[ep->last_key];
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                         /* Yikes!  Still bad signature! */
1699                         *error = -SCTP_IERROR_BAD_SIG;
1700                         goto fail;
1701                 }
1702         }
1703 
1704 no_hmac:
1705         /* IG Section 2.35.2:
1706          *  3) Compare the port numbers and the verification tag contained
1707          *     within the COOKIE ECHO chunk to the actual port numbers and the
1708          *     verification tag within the SCTP common header of the received
1709          *     packet. If these values do not match the packet MUST be silently
1710          *     discarded,
1711          */
1712         if (ntohl(chunk->sctp_hdr->vtag) != bear_cookie->my_vtag) {
1713                 *error = -SCTP_IERROR_BAD_TAG;
1714                 goto fail;
1715         }
1716 
1717         if (chunk->sctp_hdr->source != bear_cookie->peer_addr.v4.sin_port ||
1718             ntohs(chunk->sctp_hdr->dest) != bear_cookie->my_port) {
1719                 *error = -SCTP_IERROR_BAD_PORTS;
1720                 goto fail;
1721         }
1722 
1723         /* Check to see if the cookie is stale.  If there is already
1724          * an association, there is no need to check cookie's expiration
1725          * for init collision case of lost COOKIE ACK.
1726          * If skb has been timestamped, then use the stamp, otherwise
1727          * use current time.  This introduces a small possibility that
1728          * that a cookie may be considered expired, but his would only slow
1729          * down the new association establishment instead of every packet.
1730          */
1731         if (sock_flag(ep->base.sk, SOCK_TIMESTAMP))
1732                 skb_get_timestamp(skb, &tv);
1733         else
1734                 do_gettimeofday(&tv);
1735 
1736         if (!asoc && tv_lt(bear_cookie->expiration, tv)) {
1737                 /*
1738                  * Section 3.3.10.3 Stale Cookie Error (3)
1739                  *
1740                  * Cause of error
1741                  * ---------------
1742                  * Stale Cookie Error:  Indicates the receipt of a valid State
1743                  * Cookie that has expired.
1744                  */
1745                 len = ntohs(chunk->chunk_hdr->length);
1746                 *errp = sctp_make_op_error_space(asoc, chunk, len);
1747                 if (*errp) {
1748                         suseconds_t usecs = (tv.tv_sec -
1749                                 bear_cookie->expiration.tv_sec) * 1000000L +
1750                                 tv.tv_usec - bear_cookie->expiration.tv_usec;
1751                         __be32 n = htonl(usecs);
1752 
1753                         sctp_init_cause(*errp, SCTP_ERROR_STALE_COOKIE,
1754                                         sizeof(n));
1755                         sctp_addto_chunk(*errp, sizeof(n), &n);
1756                         *error = -SCTP_IERROR_STALE_COOKIE;
1757                 } else
1758                         *error = -SCTP_IERROR_NOMEM;
1759 
1760                 goto fail;
1761         }
1762 
1763         /* Make a new base association.  */
1764         scope = sctp_scope(sctp_source(chunk));
1765         retval = sctp_association_new(ep, ep->base.sk, scope, gfp);
1766         if (!retval) {
1767                 *error = -SCTP_IERROR_NOMEM;
1768                 goto fail;
1769         }
1770 
1771         /* Set up our peer's port number.  */
1772         retval->peer.port = ntohs(chunk->sctp_hdr->source);
1773 
1774         /* Populate the association from the cookie.  */
1775         memcpy(&retval->c, bear_cookie, sizeof(*bear_cookie));
1776 
1777         if (sctp_assoc_set_bind_addr_from_cookie(retval, bear_cookie,
1778                                                  GFP_ATOMIC) < 0) {
1779                 *error = -SCTP_IERROR_NOMEM;
1780                 goto fail;
1781         }
1782 
1783         /* Also, add the destination address. */
1784         if (list_empty(&retval->base.bind_addr.address_list)) {
1785                 sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest,
1786                                 SCTP_ADDR_SRC, GFP_ATOMIC);
1787         }
1788 
1789         retval->next_tsn = retval->c.initial_tsn;
1790         retval->ctsn_ack_point = retval->next_tsn - 1;
1791         retval->addip_serial = retval->c.initial_tsn;
1792         retval->adv_peer_ack_point = retval->ctsn_ack_point;
1793         retval->peer.prsctp_capable = retval->c.prsctp_capable;
1794         retval->peer.adaptation_ind = retval->c.adaptation_ind;
1795 
1796         /* The INIT stuff will be done by the side effects.  */
1797         return retval;
1798 
1799 fail:
1800         if (retval)
1801                 sctp_association_free(retval);
1802 
1803         return NULL;
1804 
1805 malformed:
1806         /* Yikes!  The packet is either corrupt or deliberately
1807          * malformed.
1808          */
1809         *error = -SCTP_IERROR_MALFORMED;
1810         goto fail;
1811 }
1812 
1813 /********************************************************************
1814  * 3rd Level Abstractions
1815  ********************************************************************/
1816 
1817 struct __sctp_missing {
1818         __be32 num_missing;
1819         __be16 type;
1820 }  __attribute__((packed));
1821 
1822 /*
1823  * Report a missing mandatory parameter.
1824  */
1825 static int sctp_process_missing_param(const struct sctp_association *asoc,
1826                                       sctp_param_t paramtype,
1827                                       struct sctp_chunk *chunk,
1828                                       struct sctp_chunk **errp)
1829 {
1830         struct __sctp_missing report;
1831         __u16 len;
1832 
1833         len = WORD_ROUND(sizeof(report));
1834 
1835         /* Make an ERROR chunk, preparing enough room for
1836          * returning multiple unknown parameters.
1837          */
1838         if (!*errp)
1839                 *errp = sctp_make_op_error_space(asoc, chunk, len);
1840 
1841         if (*errp) {
1842                 report.num_missing = htonl(1);
1843                 report.type = paramtype;
1844                 sctp_init_cause(*errp, SCTP_ERROR_MISS_PARAM,
1845                                 sizeof(report));
1846                 sctp_addto_chunk(*errp, sizeof(report), &report);
1847         }
1848 
1849         /* Stop processing this chunk. */
1850         return 0;
1851 }
1852 
1853 /* Report an Invalid Mandatory Parameter.  */
1854 static int sctp_process_inv_mandatory(const struct sctp_association *asoc,
1855                                       struct sctp_chunk *chunk,
1856                                       struct sctp_chunk **errp)
1857 {
1858         /* Invalid Mandatory Parameter Error has no payload. */
1859 
1860         if (!*errp)
1861                 *errp = sctp_make_op_error_space(asoc, chunk, 0);
1862 
1863         if (*errp)
1864                 sctp_init_cause(*errp, SCTP_ERROR_INV_PARAM, 0);
1865 
1866         /* Stop processing this chunk. */
1867         return 0;
1868 }
1869 
1870 static int sctp_process_inv_paramlength(const struct sctp_association *asoc,
1871                                         struct sctp_paramhdr *param,
1872                                         const struct sctp_chunk *chunk,
1873                                         struct sctp_chunk **errp)
1874 {
1875         /* This is a fatal error.  Any accumulated non-fatal errors are
1876          * not reported.
1877          */
1878         if (*errp)
1879                 sctp_chunk_free(*errp);
1880 
1881         /* Create an error chunk and fill it in with our payload. */
1882         *errp = sctp_make_violation_paramlen(asoc, chunk, param);
1883 
1884         return 0;
1885 }
1886 
1887 
1888 /* Do not attempt to handle the HOST_NAME parm.  However, do
1889  * send back an indicator to the peer.
1890  */
1891 static int sctp_process_hn_param(const struct sctp_association *asoc,
1892                                  union sctp_params param,
1893                                  struct sctp_chunk *chunk,
1894                                  struct sctp_chunk **errp)
1895 {
1896         __u16 len = ntohs(param.p->length);
1897 
1898         /* Processing of the HOST_NAME parameter will generate an
1899          * ABORT.  If we've accumulated any non-fatal errors, they
1900          * would be unrecognized parameters and we should not include
1901          * them in the ABORT.
1902          */
1903         if (*errp)
1904                 sctp_chunk_free(*errp);
1905 
1906         *errp = sctp_make_op_error_space(asoc, chunk, len);
1907 
1908         if (*errp) {
1909                 sctp_init_cause(*errp, SCTP_ERROR_DNS_FAILED, len);
1910                 sctp_addto_chunk(*errp, len, param.v);
1911         }
1912 
1913         /* Stop processing this chunk. */
1914         return 0;
1915 }
1916 
1917 static int sctp_verify_ext_param(union sctp_params param)
1918 {
1919         __u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
1920         int have_auth = 0;
1921         int have_asconf = 0;
1922         int i;
1923 
1924         for (i = 0; i < num_ext; i++) {
1925                 switch (param.ext->chunks[i]) {
1926                     case SCTP_CID_AUTH:
1927                             have_auth = 1;
1928                             break;
1929                     case SCTP_CID_ASCONF:
1930                     case SCTP_CID_ASCONF_ACK:
1931                             have_asconf = 1;
1932                             break;
1933                 }
1934         }
1935 
1936         /* ADD-IP Security: The draft requires us to ABORT or ignore the
1937          * INIT/INIT-ACK if ADD-IP is listed, but AUTH is not.  Do this
1938          * only if ADD-IP is turned on and we are not backward-compatible
1939          * mode.
1940          */
1941         if (sctp_addip_noauth)
1942                 return 1;
1943 
1944         if (sctp_addip_enable && !have_auth && have_asconf)
1945                 return 0;
1946 
1947         return 1;
1948 }
1949 
1950 static void sctp_process_ext_param(struct sctp_association *asoc,
1951                                     union sctp_params param)
1952 {
1953         __u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
1954         int i;
1955 
1956         for (i = 0; i < num_ext; i++) {
1957                 switch (param.ext->chunks[i]) {
1958                     case SCTP_CID_FWD_TSN:
1959                             if (sctp_prsctp_enable &&
1960                                 !asoc->peer.prsctp_capable)
1961                                     asoc->peer.prsctp_capable = 1;
1962                             break;
1963                     case SCTP_CID_AUTH:
1964                             /* if the peer reports AUTH, assume that he
1965                              * supports AUTH.
1966                              */
1967                             if (sctp_auth_enable)
1968                                     asoc->peer.auth_capable = 1;
1969                             break;
1970                     case SCTP_CID_ASCONF:
1971                     case SCTP_CID_ASCONF_ACK:
1972                             if (sctp_addip_enable)
1973                                     asoc->peer.asconf_capable = 1;
1974                             break;
1975                     default:
1976                             break;
1977                 }
1978         }
1979 }
1980 
1981 /* RFC 3.2.1 & the Implementers Guide 2.2.
1982  *
1983  * The Parameter Types are encoded such that the
1984  * highest-order two bits specify the action that must be
1985  * taken if the processing endpoint does not recognize the
1986  * Parameter Type.
1987  *
1988  * 00 - Stop processing this parameter; do not process any further
1989  *      parameters within this chunk
1990  *
1991  * 01 - Stop processing this parameter, do not process any further
1992  *      parameters within this chunk, and report the unrecognized
1993  *      parameter in an 'Unrecognized Parameter' ERROR chunk.
1994  *
1995  * 10 - Skip this parameter and continue processing.
1996  *
1997  * 11 - Skip this parameter and continue processing but
1998  *      report the unrecognized parameter in an
1999  *      'Unrecognized Parameter' ERROR chunk.
2000  *
2001  * Return value:
2002  *      SCTP_IERROR_NO_ERROR - continue with the chunk
2003  *      SCTP_IERROR_ERROR    - stop and report an error.
2004  *      SCTP_IERROR_NOMEME   - out of memory.
2005  */
2006 static sctp_ierror_t sctp_process_unk_param(const struct sctp_association *asoc,
2007                                             union sctp_params param,
2008                                             struct sctp_chunk *chunk,
2009                                             struct sctp_chunk **errp)
2010 {
2011         int retval = SCTP_IERROR_NO_ERROR;
2012 
2013         switch (param.p->type & SCTP_PARAM_ACTION_MASK) {
2014         case SCTP_PARAM_ACTION_DISCARD:
2015                 retval =  SCTP_IERROR_ERROR;
2016                 break;
2017         case SCTP_PARAM_ACTION_SKIP:
2018                 break;
2019         case SCTP_PARAM_ACTION_DISCARD_ERR:
2020                 retval =  SCTP_IERROR_ERROR;
2021                 /* Fall through */
2022         case SCTP_PARAM_ACTION_SKIP_ERR:
2023                 /* Make an ERROR chunk, preparing enough room for
2024                  * returning multiple unknown parameters.
2025                  */
2026                 if (NULL == *errp)
2027                         *errp = sctp_make_op_error_fixed(asoc, chunk);
2028 
2029                 if (*errp) {
2030                         sctp_init_cause_fixed(*errp, SCTP_ERROR_UNKNOWN_PARAM,
2031                                         WORD_ROUND(ntohs(param.p->length)));
2032                         sctp_addto_chunk_fixed(*errp,
2033                                         WORD_ROUND(ntohs(param.p->length)),
2034                                         param.v);
2035                 } else {
2036                         /* If there is no memory for generating the ERROR
2037                          * report as specified, an ABORT will be triggered
2038                          * to the peer and the association won't be
2039                          * established.
2040                          */
2041                         retval = SCTP_IERROR_NOMEM;
2042                 }
2043                 break;
2044         default:
2045                 break;
2046         }
2047 
2048         return retval;
2049 }
2050 
2051 /* Verify variable length parameters
2052  * Return values:
2053  *      SCTP_IERROR_ABORT - trigger an ABORT
2054  *      SCTP_IERROR_NOMEM - out of memory (abort)
2055  *      SCTP_IERROR_ERROR - stop processing, trigger an ERROR
2056  *      SCTP_IERROR_NO_ERROR - continue with the chunk
2057  */
2058 static sctp_ierror_t sctp_verify_param(const struct sctp_association *asoc,
2059                                         union sctp_params param,
2060                                         sctp_cid_t cid,
2061                                         struct sctp_chunk *chunk,
2062                                         struct sctp_chunk **err_chunk)
2063 {
2064         struct sctp_hmac_algo_param *hmacs;
2065         int retval = SCTP_IERROR_NO_ERROR;
2066         __u16 n_elt, id = 0;
2067         int i;
2068 
2069         /* FIXME - This routine is not looking at each parameter per the
2070          * chunk type, i.e., unrecognized parameters should be further
2071          * identified based on the chunk id.
2072          */
2073 
2074         switch (param.p->type) {
2075         case SCTP_PARAM_IPV4_ADDRESS:
2076         case SCTP_PARAM_IPV6_ADDRESS:
2077         case SCTP_PARAM_COOKIE_PRESERVATIVE:
2078         case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2079         case SCTP_PARAM_STATE_COOKIE:
2080         case SCTP_PARAM_HEARTBEAT_INFO:
2081         case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2082         case SCTP_PARAM_ECN_CAPABLE:
2083         case SCTP_PARAM_ADAPTATION_LAYER_IND:
2084                 break;
2085 
2086         case SCTP_PARAM_SUPPORTED_EXT:
2087                 if (!sctp_verify_ext_param(param))
2088                         return SCTP_IERROR_ABORT;
2089                 break;
2090 
2091         case SCTP_PARAM_SET_PRIMARY:
2092                 if (sctp_addip_enable)
2093                         break;
2094                 goto fallthrough;
2095 
2096         case SCTP_PARAM_HOST_NAME_ADDRESS:
2097                 /* Tell the peer, we won't support this param.  */
2098                 sctp_process_hn_param(asoc, param, chunk, err_chunk);
2099                 retval = SCTP_IERROR_ABORT;
2100                 break;
2101 
2102         case SCTP_PARAM_FWD_TSN_SUPPORT:
2103                 if (sctp_prsctp_enable)
2104                         break;
2105                 goto fallthrough;
2106 
2107         case SCTP_PARAM_RANDOM:
2108                 if (!sctp_auth_enable)
2109                         goto fallthrough;
2110 
2111                 /* SCTP-AUTH: Secion 6.1
2112                  * If the random number is not 32 byte long the association
2113                  * MUST be aborted.  The ABORT chunk SHOULD contain the error
2114                  * cause 'Protocol Violation'.
2115                  */
2116                 if (SCTP_AUTH_RANDOM_LENGTH !=
2117                         ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) {
2118                         sctp_process_inv_paramlength(asoc, param.p,
2119                                                         chunk, err_chunk);
2120                         retval = SCTP_IERROR_ABORT;
2121                 }
2122                 break;
2123 
2124         case SCTP_PARAM_CHUNKS:
2125                 if (!sctp_auth_enable)
2126                         goto fallthrough;
2127 
2128                 /* SCTP-AUTH: Section 3.2
2129                  * The CHUNKS parameter MUST be included once in the INIT or
2130                  *  INIT-ACK chunk if the sender wants to receive authenticated
2131                  *  chunks.  Its maximum length is 260 bytes.
2132                  */
2133                 if (260 < ntohs(param.p->length)) {
2134                         sctp_process_inv_paramlength(asoc, param.p,
2135                                                      chunk, err_chunk);
2136                         retval = SCTP_IERROR_ABORT;
2137                 }
2138                 break;
2139 
2140         case SCTP_PARAM_HMAC_ALGO:
2141                 if (!sctp_auth_enable)
2142                         goto fallthrough;
2143 
2144                 hmacs = (struct sctp_hmac_algo_param *)param.p;
2145                 n_elt = (ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) >> 1;
2146 
2147                 /* SCTP-AUTH: Section 6.1
2148                  * The HMAC algorithm based on SHA-1 MUST be supported and
2149                  * included in the HMAC-ALGO parameter.
2150                  */
2151                 for (i = 0; i < n_elt; i++) {
2152                         id = ntohs(hmacs->hmac_ids[i]);
2153 
2154                         if (id == SCTP_AUTH_HMAC_ID_SHA1)
2155                                 break;
2156                 }
2157 
2158                 if (id != SCTP_AUTH_HMAC_ID_SHA1) {
2159                         sctp_process_inv_paramlength(asoc, param.p, chunk,
2160                                                      err_chunk);
2161                         retval = SCTP_IERROR_ABORT;
2162                 }
2163                 break;
2164 fallthrough:
2165         default:
2166                 SCTP_DEBUG_PRINTK("Unrecognized param: %d for chunk %d.\n",
2167                                 ntohs(param.p->type), cid);
2168                 retval = sctp_process_unk_param(asoc, param, chunk, err_chunk);
2169                 break;
2170         }
2171         return retval;
2172 }
2173 
2174 /* Verify the INIT packet before we process it.  */
2175 int sctp_verify_init(const struct sctp_association *asoc,
2176                      sctp_cid_t cid,
2177                      sctp_init_chunk_t *peer_init,
2178                      struct sctp_chunk *chunk,
2179                      struct sctp_chunk **errp)
2180 {
2181         union sctp_params param;
2182         int has_cookie = 0;
2183         int result;
2184 
2185         /* Verify stream values are non-zero. */
2186         if ((0 == peer_init->init_hdr.num_outbound_streams) ||
2187             (0 == peer_init->init_hdr.num_inbound_streams) ||
2188             (0 == peer_init->init_hdr.init_tag) ||
2189             (SCTP_DEFAULT_MINWINDOW > ntohl(peer_init->init_hdr.a_rwnd))) {
2190 
2191                 return sctp_process_inv_mandatory(asoc, chunk, errp);
2192         }
2193 
2194         /* Check for missing mandatory parameters.  */
2195         sctp_walk_params(param, peer_init, init_hdr.params) {
2196 
2197                 if (SCTP_PARAM_STATE_COOKIE == param.p->type)
2198                         has_cookie = 1;
2199 
2200         } /* for (loop through all parameters) */
2201 
2202         /* There is a possibility that a parameter length was bad and
2203          * in that case we would have stoped walking the parameters.
2204          * The current param.p would point at the bad one.
2205          * Current consensus on the mailing list is to generate a PROTOCOL
2206          * VIOLATION error.  We build the ERROR chunk here and let the normal
2207          * error handling code build and send the packet.
2208          */
2209         if (param.v != (void*)chunk->chunk_end)
2210                 return sctp_process_inv_paramlength(asoc, param.p, chunk, errp);
2211 
2212         /* The only missing mandatory param possible today is
2213          * the state cookie for an INIT-ACK chunk.
2214          */
2215         if ((SCTP_CID_INIT_ACK == cid) && !has_cookie)
2216                 return sctp_process_missing_param(asoc, SCTP_PARAM_STATE_COOKIE,
2217                                                   chunk, errp);
2218 
2219         /* Verify all the variable length parameters */
2220         sctp_walk_params(param, peer_init, init_hdr.params) {
2221 
2222                 result = sctp_verify_param(asoc, param, cid, chunk, errp);
2223                 switch (result) {
2224                     case SCTP_IERROR_ABORT:
2225                     case SCTP_IERROR_NOMEM:
2226                                 return 0;
2227                     case SCTP_IERROR_ERROR:
2228                                 return 1;
2229                     case SCTP_IERROR_NO_ERROR:
2230                     default:
2231                                 break;
2232                 }
2233 
2234         } /* for (loop through all parameters) */
2235 
2236         return 1;
2237 }
2238 
2239 /* Unpack the parameters in an INIT packet into an association.
2240  * Returns 0 on failure, else success.
2241  * FIXME:  This is an association method.
2242  */
2243 int sctp_process_init(struct sctp_association *asoc, sctp_cid_t cid,
2244                       const union sctp_addr *peer_addr,
2245                       sctp_init_chunk_t *peer_init, gfp_t gfp)
2246 {
2247         union sctp_params param;
2248         struct sctp_transport *transport;
2249         struct list_head *pos, *temp;
2250         char *cookie;
2251 
2252         /* We must include the address that the INIT packet came from.
2253          * This is the only address that matters for an INIT packet.
2254          * When processing a COOKIE ECHO, we retrieve the from address
2255          * of the INIT from the cookie.
2256          */
2257 
2258         /* This implementation defaults to making the first transport
2259          * added as the primary transport.  The source address seems to
2260          * be a a better choice than any of the embedded addresses.
2261          */
2262         if (peer_addr) {
2263                 if(!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
2264                         goto nomem;
2265         }
2266 
2267         /* Process the initialization parameters.  */
2268         sctp_walk_params(param, peer_init, init_hdr.params) {
2269 
2270                 if (!sctp_process_param(asoc, param, peer_addr, gfp))
2271                         goto clean_up;
2272         }
2273 
2274         /* AUTH: After processing the parameters, make sure that we
2275          * have all the required info to potentially do authentications.
2276          */
2277         if (asoc->peer.auth_capable && (!asoc->peer.peer_random ||
2278                                         !asoc->peer.peer_hmacs))
2279                 asoc->peer.auth_capable = 0;
2280 
2281         /* In a non-backward compatible mode, if the peer claims
2282          * support for ADD-IP but not AUTH,  the ADD-IP spec states
2283          * that we MUST ABORT the association. Section 6.  The section
2284          * also give us an option to silently ignore the packet, which
2285          * is what we'll do here.
2286          */
2287         if (!sctp_addip_noauth &&
2288              (asoc->peer.asconf_capable && !asoc->peer.auth_capable)) {
2289                 asoc->peer.addip_disabled_mask |= (SCTP_PARAM_ADD_IP |
2290                                                   SCTP_PARAM_DEL_IP |
2291                                                   SCTP_PARAM_SET_PRIMARY);
2292                 asoc->peer.asconf_capable = 0;
2293                 goto clean_up;
2294         }
2295 
2296         /* Walk list of transports, removing transports in the UNKNOWN state. */
2297         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2298                 transport = list_entry(pos, struct sctp_transport, transports);
2299                 if (transport->state == SCTP_UNKNOWN) {
2300                         sctp_assoc_rm_peer(asoc, transport);
2301                 }
2302         }
2303 
2304         /* The fixed INIT headers are always in network byte
2305          * order.
2306          */
2307         asoc->peer.i.init_tag =
2308                 ntohl(peer_init->init_hdr.init_tag);
2309         asoc->peer.i.a_rwnd =
2310                 ntohl(peer_init->init_hdr.a_rwnd);
2311         asoc->peer.i.num_outbound_streams =
2312                 ntohs(peer_init->init_hdr.num_outbound_streams);
2313         asoc->peer.i.num_inbound_streams =
2314                 ntohs(peer_init->init_hdr.num_inbound_streams);
2315         asoc->peer.i.initial_tsn =
2316                 ntohl(peer_init->init_hdr.initial_tsn);
2317 
2318         /* Apply the upper bounds for output streams based on peer's
2319          * number of inbound streams.
2320          */
2321         if (asoc->c.sinit_num_ostreams  >
2322             ntohs(peer_init->init_hdr.num_inbound_streams)) {
2323                 asoc->c.sinit_num_ostreams =
2324                         ntohs(peer_init->init_hdr.num_inbound_streams);
2325         }
2326 
2327         if (asoc->c.sinit_max_instreams >
2328             ntohs(peer_init->init_hdr.num_outbound_streams)) {
2329                 asoc->c.sinit_max_instreams =
2330                         ntohs(peer_init->init_hdr.num_outbound_streams);
2331         }
2332 
2333         /* Copy Initiation tag from INIT to VT_peer in cookie.   */
2334         asoc->c.peer_vtag = asoc->peer.i.init_tag;
2335 
2336         /* Peer Rwnd   : Current calculated value of the peer's rwnd.  */
2337         asoc->peer.rwnd = asoc->peer.i.a_rwnd;
2338 
2339         /* Copy cookie in case we need to resend COOKIE-ECHO. */
2340         cookie = asoc->peer.cookie;
2341         if (cookie) {
2342                 asoc->peer.cookie = kmemdup(cookie, asoc->peer.cookie_len, gfp);
2343                 if (!asoc->peer.cookie)
2344                         goto clean_up;
2345         }
2346 
2347         /* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily
2348          * high (for example, implementations MAY use the size of the receiver
2349          * advertised window).
2350          */
2351         list_for_each_entry(transport, &asoc->peer.transport_addr_list,
2352                         transports) {
2353                 transport->ssthresh = asoc->peer.i.a_rwnd;
2354         }
2355 
2356         /* Set up the TSN tracking pieces.  */
2357         if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
2358                                 asoc->peer.i.initial_tsn, gfp))
2359                 goto clean_up;
2360 
2361         /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
2362          *
2363          * The stream sequence number in all the streams shall start
2364          * from 0 when the association is established.  Also, when the
2365          * stream sequence number reaches the value 65535 the next
2366          * stream sequence number shall be set to 0.
2367          */
2368 
2369         /* Allocate storage for the negotiated streams if it is not a temporary
2370          * association.
2371          */
2372         if (!asoc->temp) {
2373                 int error;
2374 
2375                 asoc->ssnmap = sctp_ssnmap_new(asoc->c.sinit_max_instreams,
2376                                                asoc->c.sinit_num_ostreams, gfp);
2377                 if (!asoc->ssnmap)
2378                         goto clean_up;
2379 
2380                 error = sctp_assoc_set_id(asoc, gfp);
2381                 if (error)
2382                         goto clean_up;
2383         }
2384 
2385         /* ADDIP Section 4.1 ASCONF Chunk Procedures
2386          *
2387          * When an endpoint has an ASCONF signaled change to be sent to the
2388          * remote endpoint it should do the following:
2389          * ...
2390          * A2) A serial number should be assigned to the Chunk. The serial
2391          * number should be a monotonically increasing number. All serial
2392          * numbers are defined to be initialized at the start of the
2393          * association to the same value as the Initial TSN.
2394          */
2395         asoc->peer.addip_serial = asoc->peer.i.initial_tsn - 1;
2396         return 1;
2397 
2398 clean_up:
2399         /* Release the transport structures. */
2400         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2401                 transport = list_entry(pos, struct sctp_transport, transports);
2402                 if (transport->state != SCTP_ACTIVE)
2403                         sctp_assoc_rm_peer(asoc, transport);
2404         }
2405 
2406 nomem:
2407         return 0;
2408 }
2409 
2410 
2411 /* Update asoc with the option described in param.
2412  *
2413  * RFC2960 3.3.2.1 Optional/Variable Length Parameters in INIT
2414  *
2415  * asoc is the association to update.
2416  * param is the variable length parameter to use for update.
2417  * cid tells us if this is an INIT, INIT ACK or COOKIE ECHO.
2418  * If the current packet is an INIT we want to minimize the amount of
2419  * work we do.  In particular, we should not build transport
2420  * structures for the addresses.
2421  */
2422 static int sctp_process_param(struct sctp_association *asoc,
2423                               union sctp_params param,
2424                               const union sctp_addr *peer_addr,
2425                               gfp_t gfp)
2426 {
2427         union sctp_addr addr;
2428         int i;
2429         __u16 sat;
2430         int retval = 1;
2431         sctp_scope_t scope;
2432         time_t stale;
2433         struct sctp_af *af;
2434         union sctp_addr_param *addr_param;
2435         struct sctp_transport *t;
2436 
2437         /* We maintain all INIT parameters in network byte order all the
2438          * time.  This allows us to not worry about whether the parameters
2439          * came from a fresh INIT, and INIT ACK, or were stored in a cookie.
2440          */
2441         switch (param.p->type) {
2442         case SCTP_PARAM_IPV6_ADDRESS:
2443                 if (PF_INET6 != asoc->base.sk->sk_family)
2444                         break;
2445                 goto do_addr_param;
2446 
2447         case SCTP_PARAM_IPV4_ADDRESS:
2448                 /* v4 addresses are not allowed on v6-only socket */
2449                 if (ipv6_only_sock(asoc->base.sk))
2450                         break;
2451 do_addr_param:
2452                 af = sctp_get_af_specific(param_type2af(param.p->type));
2453                 af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
2454                 scope = sctp_scope(peer_addr);
2455                 if (sctp_in_scope(&addr, scope))
2456                         if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
2457                                 return 0;
2458                 break;
2459 
2460         case SCTP_PARAM_COOKIE_PRESERVATIVE:
2461                 if (!sctp_cookie_preserve_enable)
2462                         break;
2463 
2464                 stale = ntohl(param.life->lifespan_increment);
2465 
2466                 /* Suggested Cookie Life span increment's unit is msec,
2467                  * (1/1000sec).
2468                  */
2469                 asoc->cookie_life.tv_sec += stale / 1000;
2470                 asoc->cookie_life.tv_usec += (stale % 1000) * 1000;
2471                 break;
2472 
2473         case SCTP_PARAM_HOST_NAME_ADDRESS:
2474                 SCTP_DEBUG_PRINTK("unimplemented SCTP_HOST_NAME_ADDRESS\n");
2475                 break;
2476 
2477         case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2478                 /* Turn off the default values first so we'll know which
2479                  * ones are really set by the peer.
2480                  */
2481                 asoc->peer.ipv4_address = 0;
2482                 asoc->peer.ipv6_address = 0;
2483 
2484                 /* Assume that peer supports the address family
2485                  * by which it sends a packet.
2486                  */
2487                 if (peer_addr->sa.sa_family == AF_INET6)
2488                         asoc->peer.ipv6_address = 1;
2489                 else if (peer_addr->sa.sa_family == AF_INET)
2490                         asoc->peer.ipv4_address = 1;
2491 
2492                 /* Cycle through address types; avoid divide by 0. */
2493                 sat = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2494                 if (sat)
2495                         sat /= sizeof(__u16);
2496 
2497                 for (i = 0; i < sat; ++i) {
2498                         switch (param.sat->types[i]) {
2499                         case SCTP_PARAM_IPV4_ADDRESS:
2500                                 asoc->peer.ipv4_address = 1;
2501                                 break;
2502 
2503                         case SCTP_PARAM_IPV6_ADDRESS:
2504                                 if (PF_INET6 == asoc->base.sk->sk_family)
2505                                         asoc->peer.ipv6_address = 1;
2506                                 break;
2507 
2508                         case SCTP_PARAM_HOST_NAME_ADDRESS:
2509                                 asoc->peer.hostname_address = 1;
2510                                 break;
2511 
2512                         default: /* Just ignore anything else.  */
2513                                 break;
2514                         }
2515                 }
2516                 break;
2517 
2518         case SCTP_PARAM_STATE_COOKIE:
2519                 asoc->peer.cookie_len =
2520                         ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2521                 asoc->peer.cookie = param.cookie->body;
2522                 break;
2523 
2524         case SCTP_PARAM_HEARTBEAT_INFO:
2525                 /* Would be odd to receive, but it causes no problems. */
2526                 break;
2527 
2528         case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2529                 /* Rejected during verify stage. */
2530                 break;
2531 
2532         case SCTP_PARAM_ECN_CAPABLE:
2533                 asoc->peer.ecn_capable = 1;
2534                 break;
2535 
2536         case SCTP_PARAM_ADAPTATION_LAYER_IND:
2537                 asoc->peer.adaptation_ind = ntohl(param.aind->adaptation_ind);
2538                 break;
2539 
2540         case SCTP_PARAM_SET_PRIMARY:
2541                 if (!sctp_addip_enable)
2542                         goto fall_through;
2543 
2544                 addr_param = param.v + sizeof(sctp_addip_param_t);
2545 
2546                 af = sctp_get_af_specific(param_type2af(param.p->type));
2547                 if (af == NULL)
2548                         break;
2549 
2550                 af->from_addr_param(&addr, addr_param,
2551                                     htons(asoc->peer.port), 0);
2552 
2553                 /* if the address is invalid, we can't process it.
2554                  * XXX: see spec for what to do.
2555                  */
2556                 if (!af->addr_valid(&addr, NULL, NULL))
2557                         break;
2558 
2559                 t = sctp_assoc_lookup_paddr(asoc, &addr);
2560                 if (!t)
2561                         break;
2562 
2563                 sctp_assoc_set_primary(asoc, t);
2564                 break;
2565 
2566         case SCTP_PARAM_SUPPORTED_EXT:
2567                 sctp_process_ext_param(asoc, param);
2568                 break;
2569 
2570         case SCTP_PARAM_FWD_TSN_SUPPORT:
2571                 if (sctp_prsctp_enable) {
2572                         asoc->peer.prsctp_capable = 1;
2573                         break;
2574                 }
2575                 /* Fall Through */
2576                 goto fall_through;
2577 
2578         case SCTP_PARAM_RANDOM:
2579                 if (!sctp_auth_enable)
2580                         goto fall_through;
2581 
2582                 /* Save peer's random parameter */
2583                 asoc->peer.peer_random = kmemdup(param.p,
2584                                             ntohs(param.p->length), gfp);
2585                 if (!asoc->peer.peer_random) {
2586                         retval = 0;
2587                         break;
2588                 }
2589                 break;
2590 
2591         case SCTP_PARAM_HMAC_ALGO:
2592                 if (!sctp_auth_enable)
2593                         goto fall_through;
2594 
2595                 /* Save peer's HMAC list */
2596                 asoc->peer.peer_hmacs = kmemdup(param.p,
2597                                             ntohs(param.p->length), gfp);
2598                 if (!asoc->peer.peer_hmacs) {
2599                         retval = 0;
2600                         break;
2601                 }
2602 
2603                 /* Set the default HMAC the peer requested*/
2604                 sctp_auth_asoc_set_default_hmac(asoc, param.hmac_algo);
2605                 break;
2606 
2607         case SCTP_PARAM_CHUNKS:
2608                 if (!sctp_auth_enable)
2609                         goto fall_through;
2610 
2611                 asoc->peer.peer_chunks = kmemdup(param.p,
2612                                             ntohs(param.p->length), gfp);
2613                 if (!asoc->peer.peer_chunks)
2614                         retval = 0;
2615                 break;
2616 fall_through:
2617         default:
2618                 /* Any unrecognized parameters should have been caught
2619                  * and handled by sctp_verify_param() which should be
2620                  * called prior to this routine.  Simply log the error
2621                  * here.
2622                  */
2623                 SCTP_DEBUG_PRINTK("Ignoring param: %d for association %p.\n",
2624                                   ntohs(param.p->type), asoc);
2625                 break;
2626         }
2627 
2628         return retval;
2629 }
2630 
2631 /* Select a new verification tag.  */
2632 __u32 sctp_generate_tag(const struct sctp_endpoint *ep)
2633 {
2634         /* I believe that this random number generator complies with RFC1750.
2635          * A tag of 0 is reserved for special cases (e.g. INIT).
2636          */
2637         __u32 x;
2638 
2639         do {
2640                 get_random_bytes(&x, sizeof(__u32));
2641         } while (x == 0);
2642 
2643         return x;
2644 }
2645 
2646 /* Select an initial TSN to send during startup.  */
2647 __u32 sctp_generate_tsn(const struct sctp_endpoint *ep)
2648 {
2649         __u32 retval;
2650 
2651         get_random_bytes(&retval, sizeof(__u32));
2652         return retval;
2653 }
2654 
2655 /*
2656  * ADDIP 3.1.1 Address Configuration Change Chunk (ASCONF)
2657  *      0                   1                   2                   3
2658  *      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
2659  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2660  *     | Type = 0xC1   |  Chunk Flags  |      Chunk Length             |
2661  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2662  *     |                       Serial Number                           |
2663  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2664  *     |                    Address Parameter                          |
2665  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2666  *     |                     ASCONF Parameter #1                       |
2667  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2668  *     \                                                               \
2669  *     /                             ....                              /
2670  *     \                                                               \
2671  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2672  *     |                     ASCONF Parameter #N                       |
2673  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2674  *
2675  * Address Parameter and other parameter will not be wrapped in this function
2676  */
2677 static struct sctp_chunk *sctp_make_asconf(struct sctp_association *asoc,
2678                                            union sctp_addr *addr,
2679                                            int vparam_len)
2680 {
2681         sctp_addiphdr_t asconf;
2682         struct sctp_chunk *retval;
2683         int length = sizeof(asconf) + vparam_len;
2684         union sctp_addr_param addrparam;
2685         int addrlen;
2686         struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
2687 
2688         addrlen = af->to_addr_param(addr, &addrparam);
2689         if (!addrlen)
2690                 return NULL;
2691         length += addrlen;
2692 
2693         /* Create the chunk.  */
2694         retval = sctp_make_chunk(asoc, SCTP_CID_ASCONF, 0, length);
2695         if (!retval)
2696                 return NULL;
2697 
2698         asconf.serial = htonl(asoc->addip_serial++);
2699 
2700         retval->subh.addip_hdr =
2701                 sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2702         retval->param_hdr.v =
2703                 sctp_addto_chunk(retval, addrlen, &addrparam);
2704 
2705         return retval;
2706 }
2707 
2708 /* ADDIP
2709  * 3.2.1 Add IP Address
2710  *      0                   1                   2                   3
2711  *      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
2712  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2713  *     |        Type = 0xC001          |    Length = Variable          |
2714  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2715  *     |               ASCONF-Request Correlation ID                   |
2716  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2717  *     |                       Address Parameter                       |
2718  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2719  *
2720  * 3.2.2 Delete IP Address
2721  *      0                   1                   2                   3
2722  *      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
2723  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2724  *     |        Type = 0xC002          |    Length = Variable          |
2725  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2726  *     |               ASCONF-Request Correlation ID                   |
2727  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2728  *     |                       Address Parameter                       |
2729  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2730  *
2731  */
2732 struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *asoc,
2733                                               union sctp_addr         *laddr,
2734                                               struct sockaddr         *addrs,
2735                                               int                     addrcnt,
2736                                               __be16                  flags)
2737 {
2738         sctp_addip_param_t      param;
2739         struct sctp_chunk       *retval;
2740         union sctp_addr_param   addr_param;
2741         union sctp_addr         *addr;
2742         void                    *addr_buf;
2743         struct sctp_af          *af;
2744         int                     paramlen = sizeof(param);
2745         int                     addr_param_len = 0;
2746         int                     totallen = 0;
2747         int                     i;
2748 
2749         /* Get total length of all the address parameters. */
2750         addr_buf = addrs;
2751         for (i = 0; i < addrcnt; i++) {
2752                 addr = (union sctp_addr *)addr_buf;
2753                 af = sctp_get_af_specific(addr->v4.sin_family);
2754                 addr_param_len = af->to_addr_param(addr, &addr_param);
2755 
2756                 totallen += paramlen;
2757                 totallen += addr_param_len;
2758 
2759                 addr_buf += af->sockaddr_len;
2760         }
2761 
2762         /* Create an asconf chunk with the required length. */
2763         retval = sctp_make_asconf(asoc, laddr, totallen);
2764         if (!retval)
2765                 return NULL;
2766 
2767         /* Add the address parameters to the asconf chunk. */
2768         addr_buf = addrs;
2769         for (i = 0; i < addrcnt; i++) {
2770                 addr = (union sctp_addr *)addr_buf;
2771                 af = sctp_get_af_specific(addr->v4.sin_family);
2772                 addr_param_len = af->to_addr_param(addr, &addr_param);
2773                 param.param_hdr.type = flags;
2774                 param.param_hdr.length = htons(paramlen + addr_param_len);
2775                 param.crr_id = i;
2776 
2777                 sctp_addto_chunk(retval, paramlen, &param);
2778                 sctp_addto_chunk(retval, addr_param_len, &addr_param);
2779 
2780                 addr_buf += af->sockaddr_len;
2781         }
2782         return retval;
2783 }
2784 
2785 /* ADDIP
2786  * 3.2.4 Set Primary IP Address
2787  *      0                   1                   2                   3
2788  *      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
2789  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2790  *     |        Type =0xC004           |    Length = Variable          |
2791  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2792  *     |               ASCONF-Request Correlation ID                   |
2793  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2794  *     |                       Address Parameter                       |
2795  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2796  *
2797  * Create an ASCONF chunk with Set Primary IP address parameter.
2798  */
2799 struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
2800                                              union sctp_addr *addr)
2801 {
2802         sctp_addip_param_t      param;
2803         struct sctp_chunk       *retval;
2804         int                     len = sizeof(param);
2805         union sctp_addr_param   addrparam;
2806         int                     addrlen;
2807         struct sctp_af          *af = sctp_get_af_specific(addr->v4.sin_family);
2808 
2809         addrlen = af->to_addr_param(addr, &addrparam);
2810         if (!addrlen)
2811                 return NULL;
2812         len += addrlen;
2813 
2814         /* Create the chunk and make asconf header. */
2815         retval = sctp_make_asconf(asoc, addr, len);
2816         if (!retval)
2817                 return NULL;
2818 
2819         param.param_hdr.type = SCTP_PARAM_SET_PRIMARY;
2820         param.param_hdr.length = htons(len);
2821         param.crr_id = 0;
2822 
2823         sctp_addto_chunk(retval, sizeof(param), &param);
2824         sctp_addto_chunk(retval, addrlen, &addrparam);
2825 
2826         return retval;
2827 }
2828 
2829 /* ADDIP 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
2830  *      0                   1                   2                   3
2831  *      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
2832  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2833  *     | Type = 0x80   |  Chunk Flags  |      Chunk Length             |
2834  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2835  *     |                       Serial Number                           |
2836  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2837  *     |                 ASCONF Parameter Response#1                   |
2838  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2839  *     \                                                               \
2840  *     /                             ....                              /
2841  *     \                                                               \
2842  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2843  *     |                 ASCONF Parameter Response#N                   |
2844  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2845  *
2846  * Create an ASCONF_ACK chunk with enough space for the parameter responses.
2847  */
2848 static struct sctp_chunk *sctp_make_asconf_ack(const struct sctp_association *asoc,
2849                                                __u32 serial, int vparam_len)
2850 {
2851         sctp_addiphdr_t         asconf;
2852         struct sctp_chunk       *retval;
2853         int                     length = sizeof(asconf) + vparam_len;
2854 
2855         /* Create the chunk.  */
2856         retval = sctp_make_chunk(asoc, SCTP_CID_ASCONF_ACK, 0, length);
2857         if (!retval)
2858                 return NULL;
2859 
2860         asconf.serial = htonl(serial);
2861 
2862         retval->subh.addip_hdr =
2863                 sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2864 
2865         return retval;
2866 }
2867 
2868 /* Add response parameters to an ASCONF_ACK chunk. */
2869 static void sctp_add_asconf_response(struct sctp_chunk *chunk, __be32 crr_id,
2870                               __be16 err_code, sctp_addip_param_t *asconf_param)
2871 {
2872         sctp_addip_param_t      ack_param;
2873         sctp_errhdr_t           err_param;
2874         int                     asconf_param_len = 0;
2875         int                     err_param_len = 0;
2876         __be16                  response_type;
2877 
2878         if (SCTP_ERROR_NO_ERROR == err_code) {
2879                 response_type = SCTP_PARAM_SUCCESS_REPORT;
2880         } else {
2881                 response_type = SCTP_PARAM_ERR_CAUSE;
2882                 err_param_len = sizeof(err_param);
2883                 if (asconf_param)
2884                         asconf_param_len =
2885                                  ntohs(asconf_param->param_hdr.length);
2886         }
2887 
2888         /* Add Success Indication or Error Cause Indication parameter. */
2889         ack_param.param_hdr.type = response_type;
2890         ack_param.param_hdr.length = htons(sizeof(ack_param) +
2891                                            err_param_len +
2892                                            asconf_param_len);
2893         ack_param.crr_id = crr_id;
2894         sctp_addto_chunk(chunk, sizeof(ack_param), &ack_param);
2895 
2896         if (SCTP_ERROR_NO_ERROR == err_code)
2897                 return;
2898 
2899         /* Add Error Cause parameter. */
2900         err_param.cause = err_code;
2901         err_param.length = htons(err_param_len + asconf_param_len);
2902         sctp_addto_chunk(chunk, err_param_len, &err_param);
2903 
2904         /* Add the failed TLV copied from ASCONF chunk. */
2905         if (asconf_param)
2906                 sctp_addto_chunk(chunk, asconf_param_len, asconf_param);
2907 }
2908 
2909 /* Process a asconf parameter. */
2910 static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
2911                                        struct sctp_chunk *asconf,
2912                                        sctp_addip_param_t *asconf_param)
2913 {
2914         struct sctp_transport *peer;
2915         struct sctp_af *af;
2916         union sctp_addr addr;
2917         union sctp_addr_param *addr_param;
2918 
2919         addr_param = (union sctp_addr_param *)
2920                         ((void *)asconf_param + sizeof(sctp_addip_param_t));
2921 
2922         if (asconf_param->param_hdr.type != SCTP_PARAM_ADD_IP &&
2923             asconf_param->param_hdr.type != SCTP_PARAM_DEL_IP &&
2924             asconf_param->param_hdr.type != SCTP_PARAM_SET_PRIMARY)
2925                 return SCTP_ERROR_UNKNOWN_PARAM;
2926 
2927         switch (addr_param->v4.param_hdr.type) {
2928         case SCTP_PARAM_IPV6_ADDRESS:
2929                 if (!asoc->peer.ipv6_address)
2930                         return SCTP_ERROR_DNS_FAILED;
2931                 break;
2932         case SCTP_PARAM_IPV4_ADDRESS:
2933                 if (!asoc->peer.ipv4_address)
2934                         return SCTP_ERROR_DNS_FAILED;
2935                 break;
2936         default:
2937                 return SCTP_ERROR_DNS_FAILED;
2938         }
2939 
2940         af = sctp_get_af_specific(param_type2af(addr_param->v4.param_hdr.type));
2941         if (unlikely(!af))
2942                 return SCTP_ERROR_DNS_FAILED;
2943 
2944         af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);
2945 
2946         /* ADDIP 4.2.1  This parameter MUST NOT contain a broadcast
2947          * or multicast address.
2948          * (note: wildcard is permitted and requires special handling so
2949          *  make sure we check for that)
2950          */
2951         if (!af->is_any(&addr) && !af->addr_valid(&addr, NULL, asconf->skb))
2952                 return SCTP_ERROR_DNS_FAILED;
2953 
2954         switch (asconf_param->param_hdr.type) {
2955         case SCTP_PARAM_ADD_IP:
2956                 /* Section 4.2.1:
2957                  * If the address 0.0.0.0 or ::0 is provided, the source
2958                  * address of the packet MUST be added.
2959                  */
2960                 if (af->is_any(&addr))
2961                         memcpy(&addr, &asconf->source, sizeof(addr));
2962 
2963                 /* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
2964                  * request and does not have the local resources to add this
2965                  * new address to the association, it MUST return an Error
2966                  * Cause TLV set to the new error code 'Operation Refused
2967                  * Due to Resource Shortage'.
2968                  */
2969 
2970                 peer = sctp_assoc_add_peer(asoc, &addr, GFP_ATOMIC, SCTP_UNCONFIRMED);
2971                 if (!peer)
2972                         return SCTP_ERROR_RSRC_LOW;
2973 
2974                 /* Start the heartbeat timer. */
2975                 if (!mod_timer(&peer->hb_timer, sctp_transport_timeout(peer)))
2976                         sctp_transport_hold(peer);
2977                 break;
2978         case SCTP_PARAM_DEL_IP:
2979                 /* ADDIP 4.3 D7) If a request is received to delete the
2980                  * last remaining IP address of a peer endpoint, the receiver
2981                  * MUST send an Error Cause TLV with the error cause set to the
2982                  * new error code 'Request to Delete Last Remaining IP Address'.
2983                  */
2984                 if (asoc->peer.transport_count == 1)
2985                         return SCTP_ERROR_DEL_LAST_IP;
2986 
2987                 /* ADDIP 4.3 D8) If a request is received to delete an IP
2988                  * address which is also the source address of the IP packet
2989                  * which contained the ASCONF chunk, the receiver MUST reject
2990                  * this request. To reject the request the receiver MUST send
2991                  * an Error Cause TLV set to the new error code 'Request to
2992                  * Delete Source IP Address'
2993                  */
2994                 if (sctp_cmp_addr_exact(sctp_source(asconf), &addr))
2995                         return SCTP_ERROR_DEL_SRC_IP;
2996 
2997                 /* Section 4.2.2
2998                  * If the address 0.0.0.0 or ::0 is provided, all
2999                  * addresses of the peer except the source address of the
3000                  * packet MUST be deleted.
3001                  */
3002                 if (af->is_any(&addr)) {
3003                         sctp_assoc_set_primary(asoc, asconf->transport);
3004                         sctp_assoc_del_nonprimary_peers(asoc,
3005                                                         asconf->transport);
3006                 } else
3007                         sctp_assoc_del_peer(asoc, &addr);
3008                 break;
3009         case SCTP_PARAM_SET_PRIMARY:
3010                 /* ADDIP Section 4.2.4
3011                  * If the address 0.0.0.0 or ::0 is provided, the receiver
3012                  * MAY mark the source address of the packet as its
3013                  * primary.
3014                  */
3015                 if (af->is_any(&addr))
3016                         memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));
3017 
3018                 peer = sctp_assoc_lookup_paddr(asoc, &addr);
3019                 if (!peer)
3020                         return SCTP_ERROR_DNS_FAILED;
3021 
3022                 sctp_assoc_set_primary(asoc, peer);
3023                 break;
3024         }
3025 
3026         return SCTP_ERROR_NO_ERROR;
3027 }
3028 
3029 /* Verify the ASCONF packet before we process it. */
3030 bool sctp_verify_asconf(const struct sctp_association *asoc,
3031                         struct sctp_chunk *chunk, bool addr_param_needed,
3032                         struct sctp_paramhdr **errp)
3033 {
3034         sctp_addip_chunk_t *addip = (sctp_addip_chunk_t *) chunk->chunk_hdr;
3035         union sctp_params param;
3036         bool addr_param_seen = false;
3037 
3038         sctp_walk_params(param, addip, addip_hdr.params) {
3039                 size_t length = ntohs(param.p->length);
3040 
3041                 *errp = param.p;
3042                 switch (param.p->type) {
3043                 case SCTP_PARAM_ERR_CAUSE:
3044                         break;
3045                 case SCTP_PARAM_IPV4_ADDRESS:
3046                         if (length != sizeof(sctp_ipv4addr_param_t))
3047                                 return false;
3048                         addr_param_seen = true;
3049                         break;
3050                 case SCTP_PARAM_IPV6_ADDRESS:
3051                         if (length != sizeof(sctp_ipv6addr_param_t))
3052                                 return false;
3053                         addr_param_seen = true;
3054                         break;
3055                 case SCTP_PARAM_ADD_IP:
3056                 case SCTP_PARAM_DEL_IP:
3057                 case SCTP_PARAM_SET_PRIMARY:
3058                         /* In ASCONF chunks, these need to be first. */
3059                         if (addr_param_needed && !addr_param_seen)
3060                                 return false;
3061                         length = ntohs(param.addip->param_hdr.length);
3062                         if (length < sizeof(sctp_addip_param_t) +
3063                                      sizeof(sctp_paramhdr_t))
3064                                 return false;
3065                         break;
3066                 case SCTP_PARAM_SUCCESS_REPORT:
3067                 case SCTP_PARAM_ADAPTATION_LAYER_IND:
3068                         if (length != sizeof(sctp_addip_param_t))
3069                                 return false;
3070                         break;
3071                 default:
3072                         /* This is unkown to us, reject! */
3073                         return false;
3074                 }
3075         }
3076 
3077         /* Remaining sanity checks. */
3078         if (addr_param_needed && !addr_param_seen)
3079                 return false;
3080         if (!addr_param_needed && addr_param_seen)
3081                 return false;
3082         if (param.v != chunk->chunk_end)
3083                 return false;
3084 
3085         return true;
3086 }
3087 
3088 /* Process an incoming ASCONF chunk with the next expected serial no. and
3089  * return an ASCONF_ACK chunk to be sent in response.
3090  */
3091 struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
3092                                        struct sctp_chunk *asconf)
3093 {
3094         sctp_addip_chunk_t *addip = (sctp_addip_chunk_t *) asconf->chunk_hdr;
3095         bool all_param_pass = true;
3096         union sctp_params param;
3097         sctp_addiphdr_t         *hdr;
3098         union sctp_addr_param   *addr_param;
3099         sctp_addip_param_t      *asconf_param;
3100         struct sctp_chunk       *asconf_ack;
3101         __be16  err_code;
3102         int     length = 0;
3103         int     chunk_len;
3104         __u32   serial;
3105 
3106         chunk_len = ntohs(asconf->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
3107         hdr = (sctp_addiphdr_t *)asconf->skb->data;
3108         serial = ntohl(hdr->serial);
3109 
3110         /* Skip the addiphdr and store a pointer to address parameter.  */
3111         length = sizeof(sctp_addiphdr_t);
3112         addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3113         chunk_len -= length;
3114 
3115         /* Skip the address parameter and store a pointer to the first
3116          * asconf parameter.
3117          */
3118         length = ntohs(addr_param->v4.param_hdr.length);
3119         asconf_param = (sctp_addip_param_t *)((void *)addr_param + length);
3120         chunk_len -= length;
3121 
3122         /* create an ASCONF_ACK chunk.
3123          * Based on the definitions of parameters, we know that the size of
3124          * ASCONF_ACK parameters are less than or equal to the twice of ASCONF
3125          * parameters.
3126          */
3127         asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 2);
3128         if (!asconf_ack)
3129                 goto done;
3130 
3131         /* Process the TLVs contained within the ASCONF chunk. */
3132         sctp_walk_params(param, addip, addip_hdr.params) {
3133                 /* Skip preceeding address parameters. */
3134                 if (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
3135                     param.p->type == SCTP_PARAM_IPV6_ADDRESS)
3136                         continue;
3137 
3138                 err_code = sctp_process_asconf_param(asoc, asconf,
3139                                                      param.addip);
3140                 /* ADDIP 4.1 A7)
3141                  * If an error response is received for a TLV parameter,
3142                  * all TLVs with no response before the failed TLV are
3143                  * considered successful if not reported.  All TLVs after
3144                  * the failed response are considered unsuccessful unless
3145                  * a specific success indication is present for the parameter.
3146                  */
3147                 if (err_code != SCTP_ERROR_NO_ERROR)
3148                         all_param_pass = false;
3149                 if (!all_param_pass)
3150                         sctp_add_asconf_response(asconf_ack, param.addip->crr_id,
3151                                                  err_code, param.addip);
3152 
3153                 /* ADDIP 4.3 D11) When an endpoint receiving an ASCONF to add
3154                  * an IP address sends an 'Out of Resource' in its response, it
3155                  * MUST also fail any subsequent add or delete requests bundled
3156                  * in the ASCONF.
3157                  */
3158                 if (err_code == SCTP_ERROR_RSRC_LOW)
3159                         goto done;
3160         }
3161 done:
3162         asoc->peer.addip_serial++;
3163 
3164         /* If we are sending a new ASCONF_ACK hold a reference to it in assoc
3165          * after freeing the reference to old asconf ack if any.
3166          */
3167         if (asconf_ack) {
3168                 sctp_chunk_hold(asconf_ack);
3169                 list_add_tail(&asconf_ack->transmitted_list,
3170                               &asoc->asconf_ack_list);
3171         }
3172 
3173         return asconf_ack;
3174 }
3175 
3176 /* Process a asconf parameter that is successfully acked. */
3177 static void sctp_asconf_param_success(struct sctp_association *asoc,
3178                                      sctp_addip_param_t *asconf_param)
3179 {
3180         struct sctp_af *af;
3181         union sctp_addr addr;
3182         struct sctp_bind_addr *bp = &asoc->base.bind_addr;
3183         union sctp_addr_param *addr_param;
3184         struct sctp_transport *transport;
3185         struct sctp_sockaddr_entry *saddr;
3186 
3187         addr_param = (union sctp_addr_param *)
3188                         ((void *)asconf_param + sizeof(sctp_addip_param_t));
3189 
3190         /* We have checked the packet before, so we do not check again. */
3191         af = sctp_get_af_specific(param_type2af(addr_param->v4.param_hdr.type));
3192         af->from_addr_param(&addr, addr_param, htons(bp->port), 0);
3193 
3194         switch (asconf_param->param_hdr.type) {
3195         case SCTP_PARAM_ADD_IP:
3196                 /* This is always done in BH context with a socket lock
3197                  * held, so the list can not change.
3198                  */
3199                 local_bh_disable();
3200                 list_for_each_entry(saddr, &bp->address_list, list) {
3201                         if (sctp_cmp_addr_exact(&saddr->a, &addr))
3202                                 saddr->state = SCTP_ADDR_SRC;
3203                 }
3204                 local_bh_enable();
3205                 list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3206                                 transports) {
3207                         if (transport->state == SCTP_ACTIVE)
3208                                 continue;
3209                         dst_release(transport->dst);
3210                         sctp_transport_route(transport, NULL,
3211                                              sctp_sk(asoc->base.sk));
3212                 }
3213                 break;
3214         case SCTP_PARAM_DEL_IP:
3215                 local_bh_disable();
3216                 sctp_del_bind_addr(bp, &addr);
3217                 local_bh_enable();
3218                 list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3219                                 transports) {
3220                         dst_release(transport->dst);
3221                         sctp_transport_route(transport, NULL,
3222                                              sctp_sk(asoc->base.sk));
3223                 }
3224                 break;
3225         default:
3226                 break;
3227         }
3228 }
3229 
3230 /* Get the corresponding ASCONF response error code from the ASCONF_ACK chunk
3231  * for the given asconf parameter.  If there is no response for this parameter,
3232  * return the error code based on the third argument 'no_err'.
3233  * ADDIP 4.1
3234  * A7) If an error response is received for a TLV parameter, all TLVs with no
3235  * response before the failed TLV are considered successful if not reported.
3236  * All TLVs after the failed response are considered unsuccessful unless a
3237  * specific success indication is present for the parameter.
3238  */
3239 static __be16 sctp_get_asconf_response(struct sctp_chunk *asconf_ack,
3240                                       sctp_addip_param_t *asconf_param,
3241                                       int no_err)
3242 {
3243         sctp_addip_param_t      *asconf_ack_param;
3244         sctp_errhdr_t           *err_param;
3245         int                     length;
3246         int                     asconf_ack_len;
3247         __be16                  err_code;
3248 
3249         if (no_err)
3250                 err_code = SCTP_ERROR_NO_ERROR;
3251         else
3252                 err_code = SCTP_ERROR_REQ_REFUSED;
3253 
3254         asconf_ack_len = ntohs(asconf_ack->chunk_hdr->length) -
3255                              sizeof(sctp_chunkhdr_t);
3256 
3257         /* Skip the addiphdr from the asconf_ack chunk and store a pointer to
3258          * the first asconf_ack parameter.
3259          */
3260         length = sizeof(sctp_addiphdr_t);
3261         asconf_ack_param = (sctp_addip_param_t *)(asconf_ack->skb->data +
3262                                                   length);
3263         asconf_ack_len -= length;
3264 
3265         while (asconf_ack_len > 0) {
3266                 if (asconf_ack_param->crr_id == asconf_param->crr_id) {
3267                         switch(asconf_ack_param->param_hdr.type) {
3268                         case SCTP_PARAM_SUCCESS_REPORT:
3269                                 return SCTP_ERROR_NO_ERROR;
3270                         case SCTP_PARAM_ERR_CAUSE:
3271                                 length = sizeof(sctp_addip_param_t);
3272                                 err_param = (sctp_errhdr_t *)
3273                                            ((void *)asconf_ack_param + length);
3274                                 asconf_ack_len -= length;
3275                                 if (asconf_ack_len > 0)
3276                                         return err_param->cause;
3277                                 else
3278                                         return SCTP_ERROR_INV_PARAM;
3279                                 break;
3280                         default:
3281                                 return SCTP_ERROR_INV_PARAM;
3282                         }
3283                 }
3284 
3285                 length = ntohs(asconf_ack_param->param_hdr.length);
3286                 asconf_ack_param = (sctp_addip_param_t *)
3287                                         ((void *)asconf_ack_param + length);
3288                 asconf_ack_len -= length;
3289         }
3290 
3291         return err_code;
3292 }
3293 
3294 /* Process an incoming ASCONF_ACK chunk against the cached last ASCONF chunk. */
3295 int sctp_process_asconf_ack(struct sctp_association *asoc,
3296                             struct sctp_chunk *asconf_ack)
3297 {
3298         struct sctp_chunk       *asconf = asoc->addip_last_asconf;
3299         union sctp_addr_param   *addr_param;
3300         sctp_addip_param_t      *asconf_param;
3301         int     length = 0;
3302         int     asconf_len = asconf->skb->len;
3303         int     all_param_pass = 0;
3304         int     no_err = 1;
3305         int     retval = 0;
3306         __be16  err_code = SCTP_ERROR_NO_ERROR;
3307 
3308         /* Skip the chunkhdr and addiphdr from the last asconf sent and store
3309          * a pointer to address parameter.
3310          */
3311         length = sizeof(sctp_addip_chunk_t);
3312         addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3313         asconf_len -= length;
3314 
3315         /* Skip the address parameter in the last asconf sent and store a
3316          * pointer to the first asconf parameter.
3317          */
3318         length = ntohs(addr_param->v4.param_hdr.length);
3319         asconf_param = (sctp_addip_param_t *)((void *)addr_param + length);
3320         asconf_len -= length;
3321 
3322         /* ADDIP 4.1
3323          * A8) If there is no response(s) to specific TLV parameter(s), and no
3324          * failures are indicated, then all request(s) are considered
3325          * successful.
3326          */
3327         if (asconf_ack->skb->len == sizeof(sctp_addiphdr_t))
3328                 all_param_pass = 1;
3329 
3330         /* Process the TLVs contained in the last sent ASCONF chunk. */
3331         while (asconf_len > 0) {
3332                 if (all_param_pass)
3333                         err_code = SCTP_ERROR_NO_ERROR;
3334                 else {
3335                         err_code = sctp_get_asconf_response(asconf_ack,
3336                                                             asconf_param,
3337                                                             no_err);
3338                         if (no_err && (SCTP_ERROR_NO_ERROR != err_code))
3339                                 no_err = 0;
3340                 }
3341 
3342                 switch (err_code) {
3343                 case SCTP_ERROR_NO_ERROR:
3344                         sctp_asconf_param_success(asoc, asconf_param);
3345                         break;
3346 
3347                 case SCTP_ERROR_RSRC_LOW:
3348                         retval = 1;
3349                         break;
3350 
3351                 case SCTP_ERROR_UNKNOWN_PARAM:
3352                         /* Disable sending this type of asconf parameter in
3353                          * future.
3354                          */
3355                         asoc->peer.addip_disabled_mask |=
3356                                 asconf_param->param_hdr.type;
3357                         break;
3358 
3359                 case SCTP_ERROR_REQ_REFUSED:
3360                 case SCTP_ERROR_DEL_LAST_IP:
3361                 case SCTP_ERROR_DEL_SRC_IP:
3362                 default:
3363                          break;
3364                 }
3365 
3366                 /* Skip the processed asconf parameter and move to the next
3367                  * one.
3368                  */
3369                 length = ntohs(asconf_param->param_hdr.length);
3370                 asconf_param = (sctp_addip_param_t *)((void *)asconf_param +
3371                                                       length);
3372                 asconf_len -= length;
3373         }
3374 
3375         /* Free the cached last sent asconf chunk. */
3376         list_del_init(&asconf->transmitted_list);
3377         sctp_chunk_free(asconf);
3378         asoc->addip_last_asconf = NULL;
3379 
3380         return retval;
3381 }
3382 
3383 /* Make a FWD TSN chunk. */
3384 struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
3385                                     __u32 new_cum_tsn, size_t nstreams,
3386                                     struct sctp_fwdtsn_skip *skiplist)
3387 {
3388         struct sctp_chunk *retval = NULL;
3389         struct sctp_fwdtsn_chunk *ftsn_chunk;
3390         struct sctp_fwdtsn_hdr ftsn_hdr;
3391         struct sctp_fwdtsn_skip skip;
3392         size_t hint;
3393         int i;
3394 
3395         hint = (nstreams + 1) * sizeof(__u32);
3396 
3397         retval = sctp_make_chunk(asoc, SCTP_CID_FWD_TSN, 0, hint);
3398 
3399         if (!retval)
3400                 return NULL;
3401 
3402         ftsn_chunk = (struct sctp_fwdtsn_chunk *)retval->subh.fwdtsn_hdr;
3403 
3404         ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
3405         retval->subh.fwdtsn_hdr =
3406                 sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
3407 
3408         for (i = 0; i < nstreams; i++) {
3409                 skip.stream = skiplist[i].stream;
3410                 skip.ssn = skiplist[i].ssn;
3411                 sctp_addto_chunk(retval, sizeof(skip), &skip);
3412         }
3413 
3414         return retval;
3415 }
3416 

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