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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, see
 27  * <http://www.gnu.org/licenses/>.
 28  *
 29  * Please send any bug reports or fixes you make to the
 30  * email address(es):
 31  *    lksctp developers <linux-sctp@vger.kernel.org>
 32  *
 33  * Written or modified by:
 34  *    La Monte H.P. Yarroll <piggy@acm.org>
 35  *    Karl Knutson          <karl@athena.chicago.il.us>
 36  *    C. Robin              <chris@hundredacre.ac.uk>
 37  *    Jon Grimm             <jgrimm@us.ibm.com>
 38  *    Xingang Guo           <xingang.guo@intel.com>
 39  *    Dajiang Zhang         <dajiang.zhang@nokia.com>
 40  *    Sridhar Samudrala     <sri@us.ibm.com>
 41  *    Daisy Chang           <daisyc@us.ibm.com>
 42  *    Ardelle Fan           <ardelle.fan@intel.com>
 43  *    Kevin Gao             <kevin.gao@intel.com>
 44  */
 45 
 46 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 47 
 48 #include <linux/types.h>
 49 #include <linux/kernel.h>
 50 #include <linux/ip.h>
 51 #include <linux/ipv6.h>
 52 #include <linux/net.h>
 53 #include <linux/inet.h>
 54 #include <linux/scatterlist.h>
 55 #include <linux/crypto.h>
 56 #include <linux/slab.h>
 57 #include <net/sock.h>
 58 
 59 #include <linux/skbuff.h>
 60 #include <linux/random.h>       /* for get_random_bytes */
 61 #include <net/sctp/sctp.h>
 62 #include <net/sctp/sm.h>
 63 
 64 static struct sctp_chunk *sctp_make_control(const struct sctp_association *asoc,
 65                                             __u8 type, __u8 flags, int paylen);
 66 static struct sctp_chunk *sctp_make_data(const struct sctp_association *asoc,
 67                                          __u8 flags, int paylen);
 68 static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc,
 69                                            __u8 type, __u8 flags, int paylen);
 70 static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
 71                                         const struct sctp_association *asoc,
 72                                         const struct sctp_chunk *init_chunk,
 73                                         int *cookie_len,
 74                                         const __u8 *raw_addrs, int addrs_len);
 75 static int sctp_process_param(struct sctp_association *asoc,
 76                               union sctp_params param,
 77                               const union sctp_addr *peer_addr,
 78                               gfp_t gfp);
 79 static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
 80                               const void *data);
 81 static void  *sctp_addto_chunk_fixed(struct sctp_chunk *, int len,
 82                                      const void *data);
 83 
 84 /* Control chunk destructor */
 85 static void sctp_control_release_owner(struct sk_buff *skb)
 86 {
 87         /*TODO: do memory release */
 88 }
 89 
 90 static void sctp_control_set_owner_w(struct sctp_chunk *chunk)
 91 {
 92         struct sctp_association *asoc = chunk->asoc;
 93         struct sk_buff *skb = chunk->skb;
 94 
 95         /* TODO: properly account for control chunks.
 96          * To do it right we'll need:
 97          *  1) endpoint if association isn't known.
 98          *  2) proper memory accounting.
 99          *
100          *  For now don't do anything for now.
101          */
102         skb->sk = asoc ? asoc->base.sk : NULL;
103         skb->destructor = sctp_control_release_owner;
104 }
105 
106 /* What was the inbound interface for this chunk? */
107 int sctp_chunk_iif(const struct sctp_chunk *chunk)
108 {
109         struct sctp_af *af;
110         int iif = 0;
111 
112         af = sctp_get_af_specific(ipver2af(ip_hdr(chunk->skb)->version));
113         if (af)
114                 iif = af->skb_iif(chunk->skb);
115 
116         return iif;
117 }
118 
119 /* RFC 2960 3.3.2 Initiation (INIT) (1)
120  *
121  * Note 2: The ECN capable field is reserved for future use of
122  * Explicit Congestion Notification.
123  */
124 static const struct sctp_paramhdr ecap_param = {
125         SCTP_PARAM_ECN_CAPABLE,
126         cpu_to_be16(sizeof(struct sctp_paramhdr)),
127 };
128 static const struct sctp_paramhdr prsctp_param = {
129         SCTP_PARAM_FWD_TSN_SUPPORT,
130         cpu_to_be16(sizeof(struct sctp_paramhdr)),
131 };
132 
133 /* A helper to initialize an op error inside a
134  * provided chunk, as most cause codes will be embedded inside an
135  * abort chunk.
136  */
137 void  sctp_init_cause(struct sctp_chunk *chunk, __be16 cause_code,
138                       size_t paylen)
139 {
140         sctp_errhdr_t err;
141         __u16 len;
142 
143         /* Cause code constants are now defined in network order.  */
144         err.cause = cause_code;
145         len = sizeof(sctp_errhdr_t) + paylen;
146         err.length  = htons(len);
147         chunk->subh.err_hdr = sctp_addto_chunk(chunk, sizeof(sctp_errhdr_t), &err);
148 }
149 
150 /* A helper to initialize an op error inside a
151  * provided chunk, as most cause codes will be embedded inside an
152  * abort chunk.  Differs from sctp_init_cause in that it won't oops
153  * if there isn't enough space in the op error chunk
154  */
155 static int sctp_init_cause_fixed(struct sctp_chunk *chunk, __be16 cause_code,
156                       size_t paylen)
157 {
158         sctp_errhdr_t err;
159         __u16 len;
160 
161         /* Cause code constants are now defined in network order.  */
162         err.cause = cause_code;
163         len = sizeof(sctp_errhdr_t) + paylen;
164         err.length  = htons(len);
165 
166         if (skb_tailroom(chunk->skb) < len)
167                 return -ENOSPC;
168         chunk->subh.err_hdr = sctp_addto_chunk_fixed(chunk,
169                                                      sizeof(sctp_errhdr_t),
170                                                      &err);
171         return 0;
172 }
173 /* 3.3.2 Initiation (INIT) (1)
174  *
175  * This chunk is used to initiate a SCTP association between two
176  * endpoints. The format of the INIT chunk is shown below:
177  *
178  *     0                   1                   2                   3
179  *     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
180  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
181  *    |   Type = 1    |  Chunk Flags  |      Chunk Length             |
182  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
183  *    |                         Initiate Tag                          |
184  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
185  *    |           Advertised Receiver Window Credit (a_rwnd)          |
186  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
187  *    |  Number of Outbound Streams   |  Number of Inbound Streams    |
188  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
189  *    |                          Initial TSN                          |
190  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
191  *    \                                                               \
192  *    /              Optional/Variable-Length Parameters              /
193  *    \                                                               \
194  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
195  *
196  *
197  * The INIT chunk contains the following parameters. Unless otherwise
198  * noted, each parameter MUST only be included once in the INIT chunk.
199  *
200  * Fixed Parameters                     Status
201  * ----------------------------------------------
202  * Initiate Tag                        Mandatory
203  * Advertised Receiver Window Credit   Mandatory
204  * Number of Outbound Streams          Mandatory
205  * Number of Inbound Streams           Mandatory
206  * Initial TSN                         Mandatory
207  *
208  * Variable Parameters                  Status     Type Value
209  * -------------------------------------------------------------
210  * IPv4 Address (Note 1)               Optional    5
211  * IPv6 Address (Note 1)               Optional    6
212  * Cookie Preservative                 Optional    9
213  * Reserved for ECN Capable (Note 2)   Optional    32768 (0x8000)
214  * Host Name Address (Note 3)          Optional    11
215  * Supported Address Types (Note 4)    Optional    12
216  */
217 struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc,
218                              const struct sctp_bind_addr *bp,
219                              gfp_t gfp, int vparam_len)
220 {
221         struct net *net = sock_net(asoc->base.sk);
222         struct sctp_endpoint *ep = asoc->ep;
223         sctp_inithdr_t init;
224         union sctp_params addrs;
225         size_t chunksize;
226         struct sctp_chunk *retval = NULL;
227         int num_types, addrs_len = 0;
228         struct sctp_sock *sp;
229         sctp_supported_addrs_param_t sat;
230         __be16 types[2];
231         sctp_adaptation_ind_param_t aiparam;
232         sctp_supported_ext_param_t ext_param;
233         int num_ext = 0;
234         __u8 extensions[3];
235         sctp_paramhdr_t *auth_chunks = NULL,
236                         *auth_hmacs = NULL;
237 
238         /* RFC 2960 3.3.2 Initiation (INIT) (1)
239          *
240          * Note 1: The INIT chunks can contain multiple addresses that
241          * can be IPv4 and/or IPv6 in any combination.
242          */
243         retval = NULL;
244 
245         /* Convert the provided bind address list to raw format. */
246         addrs = sctp_bind_addrs_to_raw(bp, &addrs_len, gfp);
247 
248         init.init_tag              = htonl(asoc->c.my_vtag);
249         init.a_rwnd                = htonl(asoc->rwnd);
250         init.num_outbound_streams  = htons(asoc->c.sinit_num_ostreams);
251         init.num_inbound_streams   = htons(asoc->c.sinit_max_instreams);
252         init.initial_tsn           = htonl(asoc->c.initial_tsn);
253 
254         /* How many address types are needed? */
255         sp = sctp_sk(asoc->base.sk);
256         num_types = sp->pf->supported_addrs(sp, types);
257 
258         chunksize = sizeof(init) + addrs_len;
259         chunksize += WORD_ROUND(SCTP_SAT_LEN(num_types));
260         chunksize += sizeof(ecap_param);
261 
262         if (net->sctp.prsctp_enable)
263                 chunksize += sizeof(prsctp_param);
264 
265         /* ADDIP: Section 4.2.7:
266          *  An implementation supporting this extension [ADDIP] MUST list
267          *  the ASCONF,the ASCONF-ACK, and the AUTH  chunks in its INIT and
268          *  INIT-ACK parameters.
269          */
270         if (net->sctp.addip_enable) {
271                 extensions[num_ext] = SCTP_CID_ASCONF;
272                 extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
273                 num_ext += 2;
274         }
275 
276         if (sp->adaptation_ind)
277                 chunksize += sizeof(aiparam);
278 
279         chunksize += vparam_len;
280 
281         /* Account for AUTH related parameters */
282         if (ep->auth_enable) {
283                 /* Add random parameter length*/
284                 chunksize += sizeof(asoc->c.auth_random);
285 
286                 /* Add HMACS parameter length if any were defined */
287                 auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
288                 if (auth_hmacs->length)
289                         chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
290                 else
291                         auth_hmacs = NULL;
292 
293                 /* Add CHUNKS parameter length */
294                 auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
295                 if (auth_chunks->length)
296                         chunksize += WORD_ROUND(ntohs(auth_chunks->length));
297                 else
298                         auth_chunks = NULL;
299 
300                 extensions[num_ext] = SCTP_CID_AUTH;
301                 num_ext += 1;
302         }
303 
304         /* If we have any extensions to report, account for that */
305         if (num_ext)
306                 chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) +
307                                         num_ext);
308 
309         /* RFC 2960 3.3.2 Initiation (INIT) (1)
310          *
311          * Note 3: An INIT chunk MUST NOT contain more than one Host
312          * Name address parameter. Moreover, the sender of the INIT
313          * MUST NOT combine any other address types with the Host Name
314          * address in the INIT. The receiver of INIT MUST ignore any
315          * other address types if the Host Name address parameter is
316          * present in the received INIT chunk.
317          *
318          * PLEASE DO NOT FIXME [This version does not support Host Name.]
319          */
320 
321         retval = sctp_make_control(asoc, SCTP_CID_INIT, 0, chunksize);
322         if (!retval)
323                 goto nodata;
324 
325         retval->subh.init_hdr =
326                 sctp_addto_chunk(retval, sizeof(init), &init);
327         retval->param_hdr.v =
328                 sctp_addto_chunk(retval, addrs_len, addrs.v);
329 
330         /* RFC 2960 3.3.2 Initiation (INIT) (1)
331          *
332          * Note 4: This parameter, when present, specifies all the
333          * address types the sending endpoint can support. The absence
334          * of this parameter indicates that the sending endpoint can
335          * support any address type.
336          */
337         sat.param_hdr.type = SCTP_PARAM_SUPPORTED_ADDRESS_TYPES;
338         sat.param_hdr.length = htons(SCTP_SAT_LEN(num_types));
339         sctp_addto_chunk(retval, sizeof(sat), &sat);
340         sctp_addto_chunk(retval, num_types * sizeof(__u16), &types);
341 
342         sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
343 
344         /* Add the supported extensions parameter.  Be nice and add this
345          * fist before addiding the parameters for the extensions themselves
346          */
347         if (num_ext) {
348                 ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
349                 ext_param.param_hdr.length =
350                             htons(sizeof(sctp_supported_ext_param_t) + num_ext);
351                 sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
352                                 &ext_param);
353                 sctp_addto_param(retval, num_ext, extensions);
354         }
355 
356         if (net->sctp.prsctp_enable)
357                 sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
358 
359         if (sp->adaptation_ind) {
360                 aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
361                 aiparam.param_hdr.length = htons(sizeof(aiparam));
362                 aiparam.adaptation_ind = htonl(sp->adaptation_ind);
363                 sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
364         }
365 
366         /* Add SCTP-AUTH chunks to the parameter list */
367         if (ep->auth_enable) {
368                 sctp_addto_chunk(retval, sizeof(asoc->c.auth_random),
369                                  asoc->c.auth_random);
370                 if (auth_hmacs)
371                         sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
372                                         auth_hmacs);
373                 if (auth_chunks)
374                         sctp_addto_chunk(retval, ntohs(auth_chunks->length),
375                                         auth_chunks);
376         }
377 nodata:
378         kfree(addrs.v);
379         return retval;
380 }
381 
382 struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc,
383                                  const struct sctp_chunk *chunk,
384                                  gfp_t gfp, int unkparam_len)
385 {
386         sctp_inithdr_t initack;
387         struct sctp_chunk *retval;
388         union sctp_params addrs;
389         struct sctp_sock *sp;
390         int addrs_len;
391         sctp_cookie_param_t *cookie;
392         int cookie_len;
393         size_t chunksize;
394         sctp_adaptation_ind_param_t aiparam;
395         sctp_supported_ext_param_t ext_param;
396         int num_ext = 0;
397         __u8 extensions[3];
398         sctp_paramhdr_t *auth_chunks = NULL,
399                         *auth_hmacs = NULL,
400                         *auth_random = NULL;
401 
402         retval = NULL;
403 
404         /* Note: there may be no addresses to embed. */
405         addrs = sctp_bind_addrs_to_raw(&asoc->base.bind_addr, &addrs_len, gfp);
406 
407         initack.init_tag                = htonl(asoc->c.my_vtag);
408         initack.a_rwnd                  = htonl(asoc->rwnd);
409         initack.num_outbound_streams    = htons(asoc->c.sinit_num_ostreams);
410         initack.num_inbound_streams     = htons(asoc->c.sinit_max_instreams);
411         initack.initial_tsn             = htonl(asoc->c.initial_tsn);
412 
413         /* FIXME:  We really ought to build the cookie right
414          * into the packet instead of allocating more fresh memory.
415          */
416         cookie = sctp_pack_cookie(asoc->ep, asoc, chunk, &cookie_len,
417                                   addrs.v, addrs_len);
418         if (!cookie)
419                 goto nomem_cookie;
420 
421         /* Calculate the total size of allocation, include the reserved
422          * space for reporting unknown parameters if it is specified.
423          */
424         sp = sctp_sk(asoc->base.sk);
425         chunksize = sizeof(initack) + addrs_len + cookie_len + unkparam_len;
426 
427         /* Tell peer that we'll do ECN only if peer advertised such cap.  */
428         if (asoc->peer.ecn_capable)
429                 chunksize += sizeof(ecap_param);
430 
431         if (asoc->peer.prsctp_capable)
432                 chunksize += sizeof(prsctp_param);
433 
434         if (asoc->peer.asconf_capable) {
435                 extensions[num_ext] = SCTP_CID_ASCONF;
436                 extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
437                 num_ext += 2;
438         }
439 
440         if (sp->adaptation_ind)
441                 chunksize += sizeof(aiparam);
442 
443         if (asoc->peer.auth_capable) {
444                 auth_random = (sctp_paramhdr_t *)asoc->c.auth_random;
445                 chunksize += ntohs(auth_random->length);
446 
447                 auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
448                 if (auth_hmacs->length)
449                         chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
450                 else
451                         auth_hmacs = NULL;
452 
453                 auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
454                 if (auth_chunks->length)
455                         chunksize += WORD_ROUND(ntohs(auth_chunks->length));
456                 else
457                         auth_chunks = NULL;
458 
459                 extensions[num_ext] = SCTP_CID_AUTH;
460                 num_ext += 1;
461         }
462 
463         if (num_ext)
464                 chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) +
465                                         num_ext);
466 
467         /* Now allocate and fill out the chunk.  */
468         retval = sctp_make_control(asoc, SCTP_CID_INIT_ACK, 0, chunksize);
469         if (!retval)
470                 goto nomem_chunk;
471 
472         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
473          *
474          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
475          * HEARTBEAT ACK, * etc.) to the same destination transport
476          * address from which it received the DATA or control chunk
477          * to which it is replying.
478          *
479          * [INIT ACK back to where the INIT came from.]
480          */
481         retval->transport = chunk->transport;
482 
483         retval->subh.init_hdr =
484                 sctp_addto_chunk(retval, sizeof(initack), &initack);
485         retval->param_hdr.v = sctp_addto_chunk(retval, addrs_len, addrs.v);
486         sctp_addto_chunk(retval, cookie_len, cookie);
487         if (asoc->peer.ecn_capable)
488                 sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
489         if (num_ext) {
490                 ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
491                 ext_param.param_hdr.length =
492                             htons(sizeof(sctp_supported_ext_param_t) + num_ext);
493                 sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
494                                  &ext_param);
495                 sctp_addto_param(retval, num_ext, extensions);
496         }
497         if (asoc->peer.prsctp_capable)
498                 sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
499 
500         if (sp->adaptation_ind) {
501                 aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
502                 aiparam.param_hdr.length = htons(sizeof(aiparam));
503                 aiparam.adaptation_ind = htonl(sp->adaptation_ind);
504                 sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
505         }
506 
507         if (asoc->peer.auth_capable) {
508                 sctp_addto_chunk(retval, ntohs(auth_random->length),
509                                  auth_random);
510                 if (auth_hmacs)
511                         sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
512                                         auth_hmacs);
513                 if (auth_chunks)
514                         sctp_addto_chunk(retval, ntohs(auth_chunks->length),
515                                         auth_chunks);
516         }
517 
518         /* We need to remove the const qualifier at this point.  */
519         retval->asoc = (struct sctp_association *) asoc;
520 
521 nomem_chunk:
522         kfree(cookie);
523 nomem_cookie:
524         kfree(addrs.v);
525         return retval;
526 }
527 
528 /* 3.3.11 Cookie Echo (COOKIE ECHO) (10):
529  *
530  * This chunk is used only during the initialization of an association.
531  * It is sent by the initiator of an association to its peer to complete
532  * the initialization process. This chunk MUST precede any DATA chunk
533  * sent within the association, but MAY be bundled with one or more DATA
534  * chunks in the same packet.
535  *
536  *      0                   1                   2                   3
537  *      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
538  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
539  *     |   Type = 10   |Chunk  Flags   |         Length                |
540  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
541  *     /                     Cookie                                    /
542  *     \                                                               \
543  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
544  *
545  * Chunk Flags: 8 bit
546  *
547  *   Set to zero on transmit and ignored on receipt.
548  *
549  * Length: 16 bits (unsigned integer)
550  *
551  *   Set to the size of the chunk in bytes, including the 4 bytes of
552  *   the chunk header and the size of the Cookie.
553  *
554  * Cookie: variable size
555  *
556  *   This field must contain the exact cookie received in the
557  *   State Cookie parameter from the previous INIT ACK.
558  *
559  *   An implementation SHOULD make the cookie as small as possible
560  *   to insure interoperability.
561  */
562 struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *asoc,
563                                     const struct sctp_chunk *chunk)
564 {
565         struct sctp_chunk *retval;
566         void *cookie;
567         int cookie_len;
568 
569         cookie = asoc->peer.cookie;
570         cookie_len = asoc->peer.cookie_len;
571 
572         /* Build a cookie echo chunk.  */
573         retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ECHO, 0, cookie_len);
574         if (!retval)
575                 goto nodata;
576         retval->subh.cookie_hdr =
577                 sctp_addto_chunk(retval, cookie_len, cookie);
578 
579         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
580          *
581          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
582          * HEARTBEAT ACK, * etc.) to the same destination transport
583          * address from which it * received the DATA or control chunk
584          * to which it is replying.
585          *
586          * [COOKIE ECHO back to where the INIT ACK came from.]
587          */
588         if (chunk)
589                 retval->transport = chunk->transport;
590 
591 nodata:
592         return retval;
593 }
594 
595 /* 3.3.12 Cookie Acknowledgement (COOKIE ACK) (11):
596  *
597  * This chunk is used only during the initialization of an
598  * association.  It is used to acknowledge the receipt of a COOKIE
599  * ECHO chunk.  This chunk MUST precede any DATA or SACK chunk sent
600  * within the association, but MAY be bundled with one or more DATA
601  * chunks or SACK chunk in the same SCTP packet.
602  *
603  *      0                   1                   2                   3
604  *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
605  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
606  *     |   Type = 11   |Chunk  Flags   |     Length = 4                |
607  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
608  *
609  * Chunk Flags: 8 bits
610  *
611  *   Set to zero on transmit and ignored on receipt.
612  */
613 struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *asoc,
614                                    const struct sctp_chunk *chunk)
615 {
616         struct sctp_chunk *retval;
617 
618         retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ACK, 0, 0);
619 
620         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
621          *
622          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
623          * HEARTBEAT ACK, * etc.) to the same destination transport
624          * address from which it * received the DATA or control chunk
625          * to which it is replying.
626          *
627          * [COOKIE ACK back to where the COOKIE ECHO came from.]
628          */
629         if (retval && chunk)
630                 retval->transport = chunk->transport;
631 
632         return retval;
633 }
634 
635 /*
636  *  Appendix A: Explicit Congestion Notification:
637  *  CWR:
638  *
639  *  RFC 2481 details a specific bit for a sender to send in the header of
640  *  its next outbound TCP segment to indicate to its peer that it has
641  *  reduced its congestion window.  This is termed the CWR bit.  For
642  *  SCTP the same indication is made by including the CWR chunk.
643  *  This chunk contains one data element, i.e. the TSN number that
644  *  was sent in the ECNE chunk.  This element represents the lowest
645  *  TSN number in the datagram that was originally marked with the
646  *  CE bit.
647  *
648  *     0                   1                   2                   3
649  *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
650  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
651  *    | Chunk Type=13 | Flags=00000000|    Chunk Length = 8           |
652  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
653  *    |                      Lowest TSN Number                        |
654  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
655  *
656  *     Note: The CWR is considered a Control chunk.
657  */
658 struct sctp_chunk *sctp_make_cwr(const struct sctp_association *asoc,
659                             const __u32 lowest_tsn,
660                             const struct sctp_chunk *chunk)
661 {
662         struct sctp_chunk *retval;
663         sctp_cwrhdr_t cwr;
664 
665         cwr.lowest_tsn = htonl(lowest_tsn);
666         retval = sctp_make_control(asoc, SCTP_CID_ECN_CWR, 0,
667                                    sizeof(sctp_cwrhdr_t));
668 
669         if (!retval)
670                 goto nodata;
671 
672         retval->subh.ecn_cwr_hdr =
673                 sctp_addto_chunk(retval, sizeof(cwr), &cwr);
674 
675         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
676          *
677          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
678          * HEARTBEAT ACK, * etc.) to the same destination transport
679          * address from which it * received the DATA or control chunk
680          * to which it is replying.
681          *
682          * [Report a reduced congestion window back to where the ECNE
683          * came from.]
684          */
685         if (chunk)
686                 retval->transport = chunk->transport;
687 
688 nodata:
689         return retval;
690 }
691 
692 /* Make an ECNE chunk.  This is a congestion experienced report.  */
693 struct sctp_chunk *sctp_make_ecne(const struct sctp_association *asoc,
694                              const __u32 lowest_tsn)
695 {
696         struct sctp_chunk *retval;
697         sctp_ecnehdr_t ecne;
698 
699         ecne.lowest_tsn = htonl(lowest_tsn);
700         retval = sctp_make_control(asoc, SCTP_CID_ECN_ECNE, 0,
701                                    sizeof(sctp_ecnehdr_t));
702         if (!retval)
703                 goto nodata;
704         retval->subh.ecne_hdr =
705                 sctp_addto_chunk(retval, sizeof(ecne), &ecne);
706 
707 nodata:
708         return retval;
709 }
710 
711 /* Make a DATA chunk for the given association from the provided
712  * parameters.  However, do not populate the data payload.
713  */
714 struct sctp_chunk *sctp_make_datafrag_empty(struct sctp_association *asoc,
715                                        const struct sctp_sndrcvinfo *sinfo,
716                                        int data_len, __u8 flags, __u16 ssn)
717 {
718         struct sctp_chunk *retval;
719         struct sctp_datahdr dp;
720         int chunk_len;
721 
722         /* We assign the TSN as LATE as possible, not here when
723          * creating the chunk.
724          */
725         dp.tsn = 0;
726         dp.stream = htons(sinfo->sinfo_stream);
727         dp.ppid   = sinfo->sinfo_ppid;
728 
729         /* Set the flags for an unordered send.  */
730         if (sinfo->sinfo_flags & SCTP_UNORDERED) {
731                 flags |= SCTP_DATA_UNORDERED;
732                 dp.ssn = 0;
733         } else
734                 dp.ssn = htons(ssn);
735 
736         chunk_len = sizeof(dp) + data_len;
737         retval = sctp_make_data(asoc, flags, chunk_len);
738         if (!retval)
739                 goto nodata;
740 
741         retval->subh.data_hdr = sctp_addto_chunk(retval, sizeof(dp), &dp);
742         memcpy(&retval->sinfo, sinfo, sizeof(struct sctp_sndrcvinfo));
743 
744 nodata:
745         return retval;
746 }
747 
748 /* Create a selective ackowledgement (SACK) for the given
749  * association.  This reports on which TSN's we've seen to date,
750  * including duplicates and gaps.
751  */
752 struct sctp_chunk *sctp_make_sack(const struct sctp_association *asoc)
753 {
754         struct sctp_chunk *retval;
755         struct sctp_sackhdr sack;
756         int len;
757         __u32 ctsn;
758         __u16 num_gabs, num_dup_tsns;
759         struct sctp_association *aptr = (struct sctp_association *)asoc;
760         struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
761         struct sctp_gap_ack_block gabs[SCTP_MAX_GABS];
762         struct sctp_transport *trans;
763 
764         memset(gabs, 0, sizeof(gabs));
765         ctsn = sctp_tsnmap_get_ctsn(map);
766 
767         pr_debug("%s: sackCTSNAck sent:0x%x\n", __func__, ctsn);
768 
769         /* How much room is needed in the chunk? */
770         num_gabs = sctp_tsnmap_num_gabs(map, gabs);
771         num_dup_tsns = sctp_tsnmap_num_dups(map);
772 
773         /* Initialize the SACK header.  */
774         sack.cum_tsn_ack            = htonl(ctsn);
775         sack.a_rwnd                 = htonl(asoc->a_rwnd);
776         sack.num_gap_ack_blocks     = htons(num_gabs);
777         sack.num_dup_tsns           = htons(num_dup_tsns);
778 
779         len = sizeof(sack)
780                 + sizeof(struct sctp_gap_ack_block) * num_gabs
781                 + sizeof(__u32) * num_dup_tsns;
782 
783         /* Create the chunk.  */
784         retval = sctp_make_control(asoc, SCTP_CID_SACK, 0, len);
785         if (!retval)
786                 goto nodata;
787 
788         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
789          *
790          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
791          * HEARTBEAT ACK, etc.) to the same destination transport
792          * address from which it received the DATA or control chunk to
793          * which it is replying.  This rule should also be followed if
794          * the endpoint is bundling DATA chunks together with the
795          * reply chunk.
796          *
797          * However, when acknowledging multiple DATA chunks received
798          * in packets from different source addresses in a single
799          * SACK, the SACK chunk may be transmitted to one of the
800          * destination transport addresses from which the DATA or
801          * control chunks being acknowledged were received.
802          *
803          * [BUG:  We do not implement the following paragraph.
804          * Perhaps we should remember the last transport we used for a
805          * SACK and avoid that (if possible) if we have seen any
806          * duplicates. --piggy]
807          *
808          * When a receiver of a duplicate DATA chunk sends a SACK to a
809          * multi- homed endpoint it MAY be beneficial to vary the
810          * destination address and not use the source address of the
811          * DATA chunk.  The reason being that receiving a duplicate
812          * from a multi-homed endpoint might indicate that the return
813          * path (as specified in the source address of the DATA chunk)
814          * for the SACK is broken.
815          *
816          * [Send to the address from which we last received a DATA chunk.]
817          */
818         retval->transport = asoc->peer.last_data_from;
819 
820         retval->subh.sack_hdr =
821                 sctp_addto_chunk(retval, sizeof(sack), &sack);
822 
823         /* Add the gap ack block information.   */
824         if (num_gabs)
825                 sctp_addto_chunk(retval, sizeof(__u32) * num_gabs,
826                                  gabs);
827 
828         /* Add the duplicate TSN information.  */
829         if (num_dup_tsns) {
830                 aptr->stats.idupchunks += num_dup_tsns;
831                 sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns,
832                                  sctp_tsnmap_get_dups(map));
833         }
834         /* Once we have a sack generated, check to see what our sack
835          * generation is, if its 0, reset the transports to 0, and reset
836          * the association generation to 1
837          *
838          * The idea is that zero is never used as a valid generation for the
839          * association so no transport will match after a wrap event like this,
840          * Until the next sack
841          */
842         if (++aptr->peer.sack_generation == 0) {
843                 list_for_each_entry(trans, &asoc->peer.transport_addr_list,
844                                     transports)
845                         trans->sack_generation = 0;
846                 aptr->peer.sack_generation = 1;
847         }
848 nodata:
849         return retval;
850 }
851 
852 /* Make a SHUTDOWN chunk. */
853 struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
854                                       const struct sctp_chunk *chunk)
855 {
856         struct sctp_chunk *retval;
857         sctp_shutdownhdr_t shut;
858         __u32 ctsn;
859 
860         ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
861         shut.cum_tsn_ack = htonl(ctsn);
862 
863         retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN, 0,
864                                    sizeof(sctp_shutdownhdr_t));
865         if (!retval)
866                 goto nodata;
867 
868         retval->subh.shutdown_hdr =
869                 sctp_addto_chunk(retval, sizeof(shut), &shut);
870 
871         if (chunk)
872                 retval->transport = chunk->transport;
873 nodata:
874         return retval;
875 }
876 
877 struct sctp_chunk *sctp_make_shutdown_ack(const struct sctp_association *asoc,
878                                      const struct sctp_chunk *chunk)
879 {
880         struct sctp_chunk *retval;
881 
882         retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_ACK, 0, 0);
883 
884         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
885          *
886          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
887          * HEARTBEAT ACK, * etc.) to the same destination transport
888          * address from which it * received the DATA or control chunk
889          * to which it is replying.
890          *
891          * [ACK back to where the SHUTDOWN came from.]
892          */
893         if (retval && chunk)
894                 retval->transport = chunk->transport;
895 
896         return retval;
897 }
898 
899 struct sctp_chunk *sctp_make_shutdown_complete(
900         const struct sctp_association *asoc,
901         const struct sctp_chunk *chunk)
902 {
903         struct sctp_chunk *retval;
904         __u8 flags = 0;
905 
906         /* Set the T-bit if we have no association (vtag will be
907          * reflected)
908          */
909         flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;
910 
911         retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags, 0);
912 
913         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
914          *
915          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
916          * HEARTBEAT ACK, * etc.) to the same destination transport
917          * address from which it * received the DATA or control chunk
918          * to which it is replying.
919          *
920          * [Report SHUTDOWN COMPLETE back to where the SHUTDOWN ACK
921          * came from.]
922          */
923         if (retval && chunk)
924                 retval->transport = chunk->transport;
925 
926         return retval;
927 }
928 
929 /* Create an ABORT.  Note that we set the T bit if we have no
930  * association, except when responding to an INIT (sctpimpguide 2.41).
931  */
932 struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc,
933                               const struct sctp_chunk *chunk,
934                               const size_t hint)
935 {
936         struct sctp_chunk *retval;
937         __u8 flags = 0;
938 
939         /* Set the T-bit if we have no association and 'chunk' is not
940          * an INIT (vtag will be reflected).
941          */
942         if (!asoc) {
943                 if (chunk && chunk->chunk_hdr &&
944                     chunk->chunk_hdr->type == SCTP_CID_INIT)
945                         flags = 0;
946                 else
947                         flags = SCTP_CHUNK_FLAG_T;
948         }
949 
950         retval = sctp_make_control(asoc, SCTP_CID_ABORT, flags, hint);
951 
952         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
953          *
954          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
955          * HEARTBEAT ACK, * etc.) to the same destination transport
956          * address from which it * received the DATA or control chunk
957          * to which it is replying.
958          *
959          * [ABORT back to where the offender came from.]
960          */
961         if (retval && chunk)
962                 retval->transport = chunk->transport;
963 
964         return retval;
965 }
966 
967 /* Helper to create ABORT with a NO_USER_DATA error.  */
968 struct sctp_chunk *sctp_make_abort_no_data(
969         const struct sctp_association *asoc,
970         const struct sctp_chunk *chunk, __u32 tsn)
971 {
972         struct sctp_chunk *retval;
973         __be32 payload;
974 
975         retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t)
976                                  + sizeof(tsn));
977 
978         if (!retval)
979                 goto no_mem;
980 
981         /* Put the tsn back into network byte order.  */
982         payload = htonl(tsn);
983         sctp_init_cause(retval, SCTP_ERROR_NO_DATA, sizeof(payload));
984         sctp_addto_chunk(retval, sizeof(payload), (const void *)&payload);
985 
986         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
987          *
988          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
989          * HEARTBEAT ACK, * etc.) to the same destination transport
990          * address from which it * received the DATA or control chunk
991          * to which it is replying.
992          *
993          * [ABORT back to where the offender came from.]
994          */
995         if (chunk)
996                 retval->transport = chunk->transport;
997 
998 no_mem:
999         return retval;
1000 }
1001 
1002 /* Helper to create ABORT with a SCTP_ERROR_USER_ABORT error.  */
1003 struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *asoc,
1004                                         const struct msghdr *msg,
1005                                         size_t paylen)
1006 {
1007         struct sctp_chunk *retval;
1008         void *payload = NULL;
1009         int err;
1010 
1011         retval = sctp_make_abort(asoc, NULL, sizeof(sctp_errhdr_t) + paylen);
1012         if (!retval)
1013                 goto err_chunk;
1014 
1015         if (paylen) {
1016                 /* Put the msg_iov together into payload.  */
1017                 payload = kmalloc(paylen, GFP_KERNEL);
1018                 if (!payload)
1019                         goto err_payload;
1020 
1021                 err = memcpy_fromiovec(payload, msg->msg_iov, paylen);
1022                 if (err < 0)
1023                         goto err_copy;
1024         }
1025 
1026         sctp_init_cause(retval, SCTP_ERROR_USER_ABORT, paylen);
1027         sctp_addto_chunk(retval, paylen, payload);
1028 
1029         if (paylen)
1030                 kfree(payload);
1031 
1032         return retval;
1033 
1034 err_copy:
1035         kfree(payload);
1036 err_payload:
1037         sctp_chunk_free(retval);
1038         retval = NULL;
1039 err_chunk:
1040         return retval;
1041 }
1042 
1043 /* Append bytes to the end of a parameter.  Will panic if chunk is not big
1044  * enough.
1045  */
1046 static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
1047                               const void *data)
1048 {
1049         void *target;
1050         int chunklen = ntohs(chunk->chunk_hdr->length);
1051 
1052         target = skb_put(chunk->skb, len);
1053 
1054         if (data)
1055                 memcpy(target, data, len);
1056         else
1057                 memset(target, 0, len);
1058 
1059         /* Adjust the chunk length field.  */
1060         chunk->chunk_hdr->length = htons(chunklen + len);
1061         chunk->chunk_end = skb_tail_pointer(chunk->skb);
1062 
1063         return target;
1064 }
1065 
1066 /* Make an ABORT chunk with a PROTOCOL VIOLATION cause code. */
1067 struct sctp_chunk *sctp_make_abort_violation(
1068         const struct sctp_association *asoc,
1069         const struct sctp_chunk *chunk,
1070         const __u8   *payload,
1071         const size_t paylen)
1072 {
1073         struct sctp_chunk  *retval;
1074         struct sctp_paramhdr phdr;
1075 
1076         retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t) + paylen
1077                                         + sizeof(sctp_paramhdr_t));
1078         if (!retval)
1079                 goto end;
1080 
1081         sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, paylen
1082                                         + sizeof(sctp_paramhdr_t));
1083 
1084         phdr.type = htons(chunk->chunk_hdr->type);
1085         phdr.length = chunk->chunk_hdr->length;
1086         sctp_addto_chunk(retval, paylen, payload);
1087         sctp_addto_param(retval, sizeof(sctp_paramhdr_t), &phdr);
1088 
1089 end:
1090         return retval;
1091 }
1092 
1093 struct sctp_chunk *sctp_make_violation_paramlen(
1094         const struct sctp_association *asoc,
1095         const struct sctp_chunk *chunk,
1096         struct sctp_paramhdr *param)
1097 {
1098         struct sctp_chunk *retval;
1099         static const char error[] = "The following parameter had invalid length:";
1100         size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t) +
1101                                 sizeof(sctp_paramhdr_t);
1102 
1103         retval = sctp_make_abort(asoc, chunk, payload_len);
1104         if (!retval)
1105                 goto nodata;
1106 
1107         sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION,
1108                         sizeof(error) + sizeof(sctp_paramhdr_t));
1109         sctp_addto_chunk(retval, sizeof(error), error);
1110         sctp_addto_param(retval, sizeof(sctp_paramhdr_t), param);
1111 
1112 nodata:
1113         return retval;
1114 }
1115 
1116 struct sctp_chunk *sctp_make_violation_max_retrans(
1117         const struct sctp_association *asoc,
1118         const struct sctp_chunk *chunk)
1119 {
1120         struct sctp_chunk *retval;
1121         static const char error[] = "Association exceeded its max_retans count";
1122         size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t);
1123 
1124         retval = sctp_make_abort(asoc, chunk, payload_len);
1125         if (!retval)
1126                 goto nodata;
1127 
1128         sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, sizeof(error));
1129         sctp_addto_chunk(retval, sizeof(error), error);
1130 
1131 nodata:
1132         return retval;
1133 }
1134 
1135 /* Make a HEARTBEAT chunk.  */
1136 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
1137                                   const struct sctp_transport *transport)
1138 {
1139         struct sctp_chunk *retval;
1140         sctp_sender_hb_info_t hbinfo;
1141 
1142         retval = sctp_make_control(asoc, SCTP_CID_HEARTBEAT, 0, sizeof(hbinfo));
1143 
1144         if (!retval)
1145                 goto nodata;
1146 
1147         hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO;
1148         hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t));
1149         hbinfo.daddr = transport->ipaddr;
1150         hbinfo.sent_at = jiffies;
1151         hbinfo.hb_nonce = transport->hb_nonce;
1152 
1153         /* Cast away the 'const', as this is just telling the chunk
1154          * what transport it belongs to.
1155          */
1156         retval->transport = (struct sctp_transport *) transport;
1157         retval->subh.hbs_hdr = sctp_addto_chunk(retval, sizeof(hbinfo),
1158                                                 &hbinfo);
1159 
1160 nodata:
1161         return retval;
1162 }
1163 
1164 struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc,
1165                                       const struct sctp_chunk *chunk,
1166                                       const void *payload, const size_t paylen)
1167 {
1168         struct sctp_chunk *retval;
1169 
1170         retval  = sctp_make_control(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen);
1171         if (!retval)
1172                 goto nodata;
1173 
1174         retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);
1175 
1176         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
1177          *
1178          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1179          * HEARTBEAT ACK, * etc.) to the same destination transport
1180          * address from which it * received the DATA or control chunk
1181          * to which it is replying.
1182          *
1183          * [HBACK back to where the HEARTBEAT came from.]
1184          */
1185         if (chunk)
1186                 retval->transport = chunk->transport;
1187 
1188 nodata:
1189         return retval;
1190 }
1191 
1192 /* Create an Operation Error chunk with the specified space reserved.
1193  * This routine can be used for containing multiple causes in the chunk.
1194  */
1195 static struct sctp_chunk *sctp_make_op_error_space(
1196         const struct sctp_association *asoc,
1197         const struct sctp_chunk *chunk,
1198         size_t size)
1199 {
1200         struct sctp_chunk *retval;
1201 
1202         retval = sctp_make_control(asoc, SCTP_CID_ERROR, 0,
1203                                    sizeof(sctp_errhdr_t) + size);
1204         if (!retval)
1205                 goto nodata;
1206 
1207         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
1208          *
1209          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1210          * HEARTBEAT ACK, etc.) to the same destination transport
1211          * address from which it received the DATA or control chunk
1212          * to which it is replying.
1213          *
1214          */
1215         if (chunk)
1216                 retval->transport = chunk->transport;
1217 
1218 nodata:
1219         return retval;
1220 }
1221 
1222 /* Create an Operation Error chunk of a fixed size,
1223  * specifically, max(asoc->pathmtu, SCTP_DEFAULT_MAXSEGMENT)
1224  * This is a helper function to allocate an error chunk for
1225  * for those invalid parameter codes in which we may not want
1226  * to report all the errors, if the incoming chunk is large
1227  */
1228 static inline struct sctp_chunk *sctp_make_op_error_fixed(
1229         const struct sctp_association *asoc,
1230         const struct sctp_chunk *chunk)
1231 {
1232         size_t size = asoc ? asoc->pathmtu : 0;
1233 
1234         if (!size)
1235                 size = SCTP_DEFAULT_MAXSEGMENT;
1236 
1237         return sctp_make_op_error_space(asoc, chunk, size);
1238 }
1239 
1240 /* Create an Operation Error chunk.  */
1241 struct sctp_chunk *sctp_make_op_error(const struct sctp_association *asoc,
1242                                  const struct sctp_chunk *chunk,
1243                                  __be16 cause_code, const void *payload,
1244                                  size_t paylen, size_t reserve_tail)
1245 {
1246         struct sctp_chunk *retval;
1247 
1248         retval = sctp_make_op_error_space(asoc, chunk, paylen + reserve_tail);
1249         if (!retval)
1250                 goto nodata;
1251 
1252         sctp_init_cause(retval, cause_code, paylen + reserve_tail);
1253         sctp_addto_chunk(retval, paylen, payload);
1254         if (reserve_tail)
1255                 sctp_addto_param(retval, reserve_tail, NULL);
1256 
1257 nodata:
1258         return retval;
1259 }
1260 
1261 struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc)
1262 {
1263         struct sctp_chunk *retval;
1264         struct sctp_hmac *hmac_desc;
1265         struct sctp_authhdr auth_hdr;
1266         __u8 *hmac;
1267 
1268         /* Get the first hmac that the peer told us to use */
1269         hmac_desc = sctp_auth_asoc_get_hmac(asoc);
1270         if (unlikely(!hmac_desc))
1271                 return NULL;
1272 
1273         retval = sctp_make_control(asoc, SCTP_CID_AUTH, 0,
1274                         hmac_desc->hmac_len + sizeof(sctp_authhdr_t));
1275         if (!retval)
1276                 return NULL;
1277 
1278         auth_hdr.hmac_id = htons(hmac_desc->hmac_id);
1279         auth_hdr.shkey_id = htons(asoc->active_key_id);
1280 
1281         retval->subh.auth_hdr = sctp_addto_chunk(retval, sizeof(sctp_authhdr_t),
1282                                                 &auth_hdr);
1283 
1284         hmac = skb_put(retval->skb, hmac_desc->hmac_len);
1285         memset(hmac, 0, hmac_desc->hmac_len);
1286 
1287         /* Adjust the chunk header to include the empty MAC */
1288         retval->chunk_hdr->length =
1289                 htons(ntohs(retval->chunk_hdr->length) + hmac_desc->hmac_len);
1290         retval->chunk_end = skb_tail_pointer(retval->skb);
1291 
1292         return retval;
1293 }
1294 
1295 
1296 /********************************************************************
1297  * 2nd Level Abstractions
1298  ********************************************************************/
1299 
1300 /* Turn an skb into a chunk.
1301  * FIXME: Eventually move the structure directly inside the skb->cb[].
1302  *
1303  * sctpimpguide-05.txt Section 2.8.2
1304  * M1) Each time a new DATA chunk is transmitted
1305  * set the 'TSN.Missing.Report' count for that TSN to 0. The
1306  * 'TSN.Missing.Report' count will be used to determine missing chunks
1307  * and when to fast retransmit.
1308  *
1309  */
1310 struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
1311                             const struct sctp_association *asoc,
1312                             struct sock *sk)
1313 {
1314         struct sctp_chunk *retval;
1315 
1316         retval = kmem_cache_zalloc(sctp_chunk_cachep, GFP_ATOMIC);
1317 
1318         if (!retval)
1319                 goto nodata;
1320         if (!sk)
1321                 pr_debug("%s: chunkifying skb:%p w/o an sk\n", __func__, skb);
1322 
1323         INIT_LIST_HEAD(&retval->list);
1324         retval->skb             = skb;
1325         retval->asoc            = (struct sctp_association *)asoc;
1326         retval->singleton       = 1;
1327 
1328         retval->fast_retransmit = SCTP_CAN_FRTX;
1329 
1330         /* Polish the bead hole.  */
1331         INIT_LIST_HEAD(&retval->transmitted_list);
1332         INIT_LIST_HEAD(&retval->frag_list);
1333         SCTP_DBG_OBJCNT_INC(chunk);
1334         atomic_set(&retval->refcnt, 1);
1335 
1336 nodata:
1337         return retval;
1338 }
1339 
1340 /* Set chunk->source and dest based on the IP header in chunk->skb.  */
1341 void sctp_init_addrs(struct sctp_chunk *chunk, union sctp_addr *src,
1342                      union sctp_addr *dest)
1343 {
1344         memcpy(&chunk->source, src, sizeof(union sctp_addr));
1345         memcpy(&chunk->dest, dest, sizeof(union sctp_addr));
1346 }
1347 
1348 /* Extract the source address from a chunk.  */
1349 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk)
1350 {
1351         /* If we have a known transport, use that.  */
1352         if (chunk->transport) {
1353                 return &chunk->transport->ipaddr;
1354         } else {
1355                 /* Otherwise, extract it from the IP header.  */
1356                 return &chunk->source;
1357         }
1358 }
1359 
1360 /* Create a new chunk, setting the type and flags headers from the
1361  * arguments, reserving enough space for a 'paylen' byte payload.
1362  */
1363 static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc,
1364                                             __u8 type, __u8 flags, int paylen)
1365 {
1366         struct sctp_chunk *retval;
1367         sctp_chunkhdr_t *chunk_hdr;
1368         struct sk_buff *skb;
1369         struct sock *sk;
1370 
1371         /* No need to allocate LL here, as this is only a chunk. */
1372         skb = alloc_skb(WORD_ROUND(sizeof(sctp_chunkhdr_t) + paylen),
1373                         GFP_ATOMIC);
1374         if (!skb)
1375                 goto nodata;
1376 
1377         /* Make room for the chunk header.  */
1378         chunk_hdr = (sctp_chunkhdr_t *)skb_put(skb, sizeof(sctp_chunkhdr_t));
1379         chunk_hdr->type   = type;
1380         chunk_hdr->flags  = flags;
1381         chunk_hdr->length = htons(sizeof(sctp_chunkhdr_t));
1382 
1383         sk = asoc ? asoc->base.sk : NULL;
1384         retval = sctp_chunkify(skb, asoc, sk);
1385         if (!retval) {
1386                 kfree_skb(skb);
1387                 goto nodata;
1388         }
1389 
1390         retval->chunk_hdr = chunk_hdr;
1391         retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(struct sctp_chunkhdr);
1392 
1393         /* Determine if the chunk needs to be authenticated */
1394         if (sctp_auth_send_cid(type, asoc))
1395                 retval->auth = 1;
1396 
1397         return retval;
1398 nodata:
1399         return NULL;
1400 }
1401 
1402 static struct sctp_chunk *sctp_make_data(const struct sctp_association *asoc,
1403                                          __u8 flags, int paylen)
1404 {
1405         return _sctp_make_chunk(asoc, SCTP_CID_DATA, flags, paylen);
1406 }
1407 
1408 static struct sctp_chunk *sctp_make_control(const struct sctp_association *asoc,
1409                                             __u8 type, __u8 flags, int paylen)
1410 {
1411         struct sctp_chunk *chunk = _sctp_make_chunk(asoc, type, flags, paylen);
1412 
1413         if (chunk)
1414                 sctp_control_set_owner_w(chunk);
1415 
1416         return chunk;
1417 }
1418 
1419 /* Release the memory occupied by a chunk.  */
1420 static void sctp_chunk_destroy(struct sctp_chunk *chunk)
1421 {
1422         BUG_ON(!list_empty(&chunk->list));
1423         list_del_init(&chunk->transmitted_list);
1424 
1425         consume_skb(chunk->skb);
1426         consume_skb(chunk->auth_chunk);
1427 
1428         SCTP_DBG_OBJCNT_DEC(chunk);
1429         kmem_cache_free(sctp_chunk_cachep, chunk);
1430 }
1431 
1432 /* Possibly, free the chunk.  */
1433 void sctp_chunk_free(struct sctp_chunk *chunk)
1434 {
1435         /* Release our reference on the message tracker. */
1436         if (chunk->msg)
1437                 sctp_datamsg_put(chunk->msg);
1438 
1439         sctp_chunk_put(chunk);
1440 }
1441 
1442 /* Grab a reference to the chunk. */
1443 void sctp_chunk_hold(struct sctp_chunk *ch)
1444 {
1445         atomic_inc(&ch->refcnt);
1446 }
1447 
1448 /* Release a reference to the chunk. */
1449 void sctp_chunk_put(struct sctp_chunk *ch)
1450 {
1451         if (atomic_dec_and_test(&ch->refcnt))
1452                 sctp_chunk_destroy(ch);
1453 }
1454 
1455 /* Append bytes to the end of a chunk.  Will panic if chunk is not big
1456  * enough.
1457  */
1458 void *sctp_addto_chunk(struct sctp_chunk *chunk, int len, const void *data)
1459 {
1460         void *target;
1461         void *padding;
1462         int chunklen = ntohs(chunk->chunk_hdr->length);
1463         int padlen = WORD_ROUND(chunklen) - chunklen;
1464 
1465         padding = skb_put(chunk->skb, padlen);
1466         target = skb_put(chunk->skb, len);
1467 
1468         memset(padding, 0, padlen);
1469         memcpy(target, data, len);
1470 
1471         /* Adjust the chunk length field.  */
1472         chunk->chunk_hdr->length = htons(chunklen + padlen + len);
1473         chunk->chunk_end = skb_tail_pointer(chunk->skb);
1474 
1475         return target;
1476 }
1477 
1478 /* Append bytes to the end of a chunk. Returns NULL if there isn't sufficient
1479  * space in the chunk
1480  */
1481 static void *sctp_addto_chunk_fixed(struct sctp_chunk *chunk,
1482                                     int len, const void *data)
1483 {
1484         if (skb_tailroom(chunk->skb) >= len)
1485                 return sctp_addto_chunk(chunk, len, data);
1486         else
1487                 return NULL;
1488 }
1489 
1490 /* Append bytes from user space to the end of a chunk.  Will panic if
1491  * chunk is not big enough.
1492  * Returns a kernel err value.
1493  */
1494 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int off, int len,
1495                           struct iovec *data)
1496 {
1497         __u8 *target;
1498         int err = 0;
1499 
1500         /* Make room in chunk for data.  */
1501         target = skb_put(chunk->skb, len);
1502 
1503         /* Copy data (whole iovec) into chunk */
1504         if ((err = memcpy_fromiovecend(target, data, off, len)))
1505                 goto out;
1506 
1507         /* Adjust the chunk length field.  */
1508         chunk->chunk_hdr->length =
1509                 htons(ntohs(chunk->chunk_hdr->length) + len);
1510         chunk->chunk_end = skb_tail_pointer(chunk->skb);
1511 
1512 out:
1513         return err;
1514 }
1515 
1516 /* Helper function to assign a TSN if needed.  This assumes that both
1517  * the data_hdr and association have already been assigned.
1518  */
1519 void sctp_chunk_assign_ssn(struct sctp_chunk *chunk)
1520 {
1521         struct sctp_datamsg *msg;
1522         struct sctp_chunk *lchunk;
1523         struct sctp_stream *stream;
1524         __u16 ssn;
1525         __u16 sid;
1526 
1527         if (chunk->has_ssn)
1528                 return;
1529 
1530         /* All fragments will be on the same stream */
1531         sid = ntohs(chunk->subh.data_hdr->stream);
1532         stream = &chunk->asoc->ssnmap->out;
1533 
1534         /* Now assign the sequence number to the entire message.
1535          * All fragments must have the same stream sequence number.
1536          */
1537         msg = chunk->msg;
1538         list_for_each_entry(lchunk, &msg->chunks, frag_list) {
1539                 if (lchunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
1540                         ssn = 0;
1541                 } else {
1542                         if (lchunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG)
1543                                 ssn = sctp_ssn_next(stream, sid);
1544                         else
1545                                 ssn = sctp_ssn_peek(stream, sid);
1546                 }
1547 
1548                 lchunk->subh.data_hdr->ssn = htons(ssn);
1549                 lchunk->has_ssn = 1;
1550         }
1551 }
1552 
1553 /* Helper function to assign a TSN if needed.  This assumes that both
1554  * the data_hdr and association have already been assigned.
1555  */
1556 void sctp_chunk_assign_tsn(struct sctp_chunk *chunk)
1557 {
1558         if (!chunk->has_tsn) {
1559                 /* This is the last possible instant to
1560                  * assign a TSN.
1561                  */
1562                 chunk->subh.data_hdr->tsn =
1563                         htonl(sctp_association_get_next_tsn(chunk->asoc));
1564                 chunk->has_tsn = 1;
1565         }
1566 }
1567 
1568 /* Create a CLOSED association to use with an incoming packet.  */
1569 struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *ep,
1570                                         struct sctp_chunk *chunk,
1571                                         gfp_t gfp)
1572 {
1573         struct sctp_association *asoc;
1574         struct sk_buff *skb;
1575         sctp_scope_t scope;
1576         struct sctp_af *af;
1577 
1578         /* Create the bare association.  */
1579         scope = sctp_scope(sctp_source(chunk));
1580         asoc = sctp_association_new(ep, ep->base.sk, scope, gfp);
1581         if (!asoc)
1582                 goto nodata;
1583         asoc->temp = 1;
1584         skb = chunk->skb;
1585         /* Create an entry for the source address of the packet.  */
1586         af = sctp_get_af_specific(ipver2af(ip_hdr(skb)->version));
1587         if (unlikely(!af))
1588                 goto fail;
1589         af->from_skb(&asoc->c.peer_addr, skb, 1);
1590 nodata:
1591         return asoc;
1592 
1593 fail:
1594         sctp_association_free(asoc);
1595         return NULL;
1596 }
1597 
1598 /* Build a cookie representing asoc.
1599  * This INCLUDES the param header needed to put the cookie in the INIT ACK.
1600  */
1601 static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
1602                                       const struct sctp_association *asoc,
1603                                       const struct sctp_chunk *init_chunk,
1604                                       int *cookie_len,
1605                                       const __u8 *raw_addrs, int addrs_len)
1606 {
1607         sctp_cookie_param_t *retval;
1608         struct sctp_signed_cookie *cookie;
1609         struct scatterlist sg;
1610         int headersize, bodysize;
1611 
1612         /* Header size is static data prior to the actual cookie, including
1613          * any padding.
1614          */
1615         headersize = sizeof(sctp_paramhdr_t) +
1616                      (sizeof(struct sctp_signed_cookie) -
1617                       sizeof(struct sctp_cookie));
1618         bodysize = sizeof(struct sctp_cookie)
1619                 + ntohs(init_chunk->chunk_hdr->length) + addrs_len;
1620 
1621         /* Pad out the cookie to a multiple to make the signature
1622          * functions simpler to write.
1623          */
1624         if (bodysize % SCTP_COOKIE_MULTIPLE)
1625                 bodysize += SCTP_COOKIE_MULTIPLE
1626                         - (bodysize % SCTP_COOKIE_MULTIPLE);
1627         *cookie_len = headersize + bodysize;
1628 
1629         /* Clear this memory since we are sending this data structure
1630          * out on the network.
1631          */
1632         retval = kzalloc(*cookie_len, GFP_ATOMIC);
1633         if (!retval)
1634                 goto nodata;
1635 
1636         cookie = (struct sctp_signed_cookie *) retval->body;
1637 
1638         /* Set up the parameter header.  */
1639         retval->p.type = SCTP_PARAM_STATE_COOKIE;
1640         retval->p.length = htons(*cookie_len);
1641 
1642         /* Copy the cookie part of the association itself.  */
1643         cookie->c = asoc->c;
1644         /* Save the raw address list length in the cookie. */
1645         cookie->c.raw_addr_list_len = addrs_len;
1646 
1647         /* Remember PR-SCTP capability. */
1648         cookie->c.prsctp_capable = asoc->peer.prsctp_capable;
1649 
1650         /* Save adaptation indication in the cookie. */
1651         cookie->c.adaptation_ind = asoc->peer.adaptation_ind;
1652 
1653         /* Set an expiration time for the cookie.  */
1654         cookie->c.expiration = ktime_add(asoc->cookie_life,
1655                                          ktime_get_real());
1656 
1657         /* Copy the peer's init packet.  */
1658         memcpy(&cookie->c.peer_init[0], init_chunk->chunk_hdr,
1659                ntohs(init_chunk->chunk_hdr->length));
1660 
1661         /* Copy the raw local address list of the association. */
1662         memcpy((__u8 *)&cookie->c.peer_init[0] +
1663                ntohs(init_chunk->chunk_hdr->length), raw_addrs, addrs_len);
1664 
1665         if (sctp_sk(ep->base.sk)->hmac) {
1666                 struct hash_desc desc;
1667 
1668                 /* Sign the message.  */
1669                 sg_init_one(&sg, &cookie->c, bodysize);
1670                 desc.tfm = sctp_sk(ep->base.sk)->hmac;
1671                 desc.flags = 0;
1672 
1673                 if (crypto_hash_setkey(desc.tfm, ep->secret_key,
1674                                        sizeof(ep->secret_key)) ||
1675                     crypto_hash_digest(&desc, &sg, bodysize, cookie->signature))
1676                         goto free_cookie;
1677         }
1678 
1679         return retval;
1680 
1681 free_cookie:
1682         kfree(retval);
1683 nodata:
1684         *cookie_len = 0;
1685         return NULL;
1686 }
1687 
1688 /* Unpack the cookie from COOKIE ECHO chunk, recreating the association.  */
1689 struct sctp_association *sctp_unpack_cookie(
1690         const struct sctp_endpoint *ep,
1691         const struct sctp_association *asoc,
1692         struct sctp_chunk *chunk, gfp_t gfp,
1693         int *error, struct sctp_chunk **errp)
1694 {
1695         struct sctp_association *retval = NULL;
1696         struct sctp_signed_cookie *cookie;
1697         struct sctp_cookie *bear_cookie;
1698         int headersize, bodysize, fixed_size;
1699         __u8 *digest = ep->digest;
1700         struct scatterlist sg;
1701         unsigned int len;
1702         sctp_scope_t scope;
1703         struct sk_buff *skb = chunk->skb;
1704         ktime_t kt;
1705         struct hash_desc desc;
1706 
1707         /* Header size is static data prior to the actual cookie, including
1708          * any padding.
1709          */
1710         headersize = sizeof(sctp_chunkhdr_t) +
1711                      (sizeof(struct sctp_signed_cookie) -
1712                       sizeof(struct sctp_cookie));
1713         bodysize = ntohs(chunk->chunk_hdr->length) - headersize;
1714         fixed_size = headersize + sizeof(struct sctp_cookie);
1715 
1716         /* Verify that the chunk looks like it even has a cookie.
1717          * There must be enough room for our cookie and our peer's
1718          * INIT chunk.
1719          */
1720         len = ntohs(chunk->chunk_hdr->length);
1721         if (len < fixed_size + sizeof(struct sctp_chunkhdr))
1722                 goto malformed;
1723 
1724         /* Verify that the cookie has been padded out. */
1725         if (bodysize % SCTP_COOKIE_MULTIPLE)
1726                 goto malformed;
1727 
1728         /* Process the cookie.  */
1729         cookie = chunk->subh.cookie_hdr;
1730         bear_cookie = &cookie->c;
1731 
1732         if (!sctp_sk(ep->base.sk)->hmac)
1733                 goto no_hmac;
1734 
1735         /* Check the signature.  */
1736         sg_init_one(&sg, bear_cookie, bodysize);
1737         desc.tfm = sctp_sk(ep->base.sk)->hmac;
1738         desc.flags = 0;
1739 
1740         memset(digest, 0x00, SCTP_SIGNATURE_SIZE);
1741         if (crypto_hash_setkey(desc.tfm, ep->secret_key,
1742                                sizeof(ep->secret_key)) ||
1743             crypto_hash_digest(&desc, &sg, bodysize, digest)) {
1744                 *error = -SCTP_IERROR_NOMEM;
1745                 goto fail;
1746         }
1747 
1748         if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
1749                 *error = -SCTP_IERROR_BAD_SIG;
1750                 goto fail;
1751         }
1752 
1753 no_hmac:
1754         /* IG Section 2.35.2:
1755          *  3) Compare the port numbers and the verification tag contained
1756          *     within the COOKIE ECHO chunk to the actual port numbers and the
1757          *     verification tag within the SCTP common header of the received
1758          *     packet. If these values do not match the packet MUST be silently
1759          *     discarded,
1760          */
1761         if (ntohl(chunk->sctp_hdr->vtag) != bear_cookie->my_vtag) {
1762                 *error = -SCTP_IERROR_BAD_TAG;
1763                 goto fail;
1764         }
1765 
1766         if (chunk->sctp_hdr->source != bear_cookie->peer_addr.v4.sin_port ||
1767             ntohs(chunk->sctp_hdr->dest) != bear_cookie->my_port) {
1768                 *error = -SCTP_IERROR_BAD_PORTS;
1769                 goto fail;
1770         }
1771 
1772         /* Check to see if the cookie is stale.  If there is already
1773          * an association, there is no need to check cookie's expiration
1774          * for init collision case of lost COOKIE ACK.
1775          * If skb has been timestamped, then use the stamp, otherwise
1776          * use current time.  This introduces a small possibility that
1777          * that a cookie may be considered expired, but his would only slow
1778          * down the new association establishment instead of every packet.
1779          */
1780         if (sock_flag(ep->base.sk, SOCK_TIMESTAMP))
1781                 kt = skb_get_ktime(skb);
1782         else
1783                 kt = ktime_get_real();
1784 
1785         if (!asoc && ktime_compare(bear_cookie->expiration, kt) < 0) {
1786                 /*
1787                  * Section 3.3.10.3 Stale Cookie Error (3)
1788                  *
1789                  * Cause of error
1790                  * ---------------
1791                  * Stale Cookie Error:  Indicates the receipt of a valid State
1792                  * Cookie that has expired.
1793                  */
1794                 len = ntohs(chunk->chunk_hdr->length);
1795                 *errp = sctp_make_op_error_space(asoc, chunk, len);
1796                 if (*errp) {
1797                         suseconds_t usecs = ktime_to_us(ktime_sub(kt, bear_cookie->expiration));
1798                         __be32 n = htonl(usecs);
1799 
1800                         sctp_init_cause(*errp, SCTP_ERROR_STALE_COOKIE,
1801                                         sizeof(n));
1802                         sctp_addto_chunk(*errp, sizeof(n), &n);
1803                         *error = -SCTP_IERROR_STALE_COOKIE;
1804                 } else
1805                         *error = -SCTP_IERROR_NOMEM;
1806 
1807                 goto fail;
1808         }
1809 
1810         /* Make a new base association.  */
1811         scope = sctp_scope(sctp_source(chunk));
1812         retval = sctp_association_new(ep, ep->base.sk, scope, gfp);
1813         if (!retval) {
1814                 *error = -SCTP_IERROR_NOMEM;
1815                 goto fail;
1816         }
1817 
1818         /* Set up our peer's port number.  */
1819         retval->peer.port = ntohs(chunk->sctp_hdr->source);
1820 
1821         /* Populate the association from the cookie.  */
1822         memcpy(&retval->c, bear_cookie, sizeof(*bear_cookie));
1823 
1824         if (sctp_assoc_set_bind_addr_from_cookie(retval, bear_cookie,
1825                                                  GFP_ATOMIC) < 0) {
1826                 *error = -SCTP_IERROR_NOMEM;
1827                 goto fail;
1828         }
1829 
1830         /* Also, add the destination address. */
1831         if (list_empty(&retval->base.bind_addr.address_list)) {
1832                 sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest,
1833                                 SCTP_ADDR_SRC, GFP_ATOMIC);
1834         }
1835 
1836         retval->next_tsn = retval->c.initial_tsn;
1837         retval->ctsn_ack_point = retval->next_tsn - 1;
1838         retval->addip_serial = retval->c.initial_tsn;
1839         retval->adv_peer_ack_point = retval->ctsn_ack_point;
1840         retval->peer.prsctp_capable = retval->c.prsctp_capable;
1841         retval->peer.adaptation_ind = retval->c.adaptation_ind;
1842 
1843         /* The INIT stuff will be done by the side effects.  */
1844         return retval;
1845 
1846 fail:
1847         if (retval)
1848                 sctp_association_free(retval);
1849 
1850         return NULL;
1851 
1852 malformed:
1853         /* Yikes!  The packet is either corrupt or deliberately
1854          * malformed.
1855          */
1856         *error = -SCTP_IERROR_MALFORMED;
1857         goto fail;
1858 }
1859 
1860 /********************************************************************
1861  * 3rd Level Abstractions
1862  ********************************************************************/
1863 
1864 struct __sctp_missing {
1865         __be32 num_missing;
1866         __be16 type;
1867 }  __packed;
1868 
1869 /*
1870  * Report a missing mandatory parameter.
1871  */
1872 static int sctp_process_missing_param(const struct sctp_association *asoc,
1873                                       sctp_param_t paramtype,
1874                                       struct sctp_chunk *chunk,
1875                                       struct sctp_chunk **errp)
1876 {
1877         struct __sctp_missing report;
1878         __u16 len;
1879 
1880         len = WORD_ROUND(sizeof(report));
1881 
1882         /* Make an ERROR chunk, preparing enough room for
1883          * returning multiple unknown parameters.
1884          */
1885         if (!*errp)
1886                 *errp = sctp_make_op_error_space(asoc, chunk, len);
1887 
1888         if (*errp) {
1889                 report.num_missing = htonl(1);
1890                 report.type = paramtype;
1891                 sctp_init_cause(*errp, SCTP_ERROR_MISS_PARAM,
1892                                 sizeof(report));
1893                 sctp_addto_chunk(*errp, sizeof(report), &report);
1894         }
1895 
1896         /* Stop processing this chunk. */
1897         return 0;
1898 }
1899 
1900 /* Report an Invalid Mandatory Parameter.  */
1901 static int sctp_process_inv_mandatory(const struct sctp_association *asoc,
1902                                       struct sctp_chunk *chunk,
1903                                       struct sctp_chunk **errp)
1904 {
1905         /* Invalid Mandatory Parameter Error has no payload. */
1906 
1907         if (!*errp)
1908                 *errp = sctp_make_op_error_space(asoc, chunk, 0);
1909 
1910         if (*errp)
1911                 sctp_init_cause(*errp, SCTP_ERROR_INV_PARAM, 0);
1912 
1913         /* Stop processing this chunk. */
1914         return 0;
1915 }
1916 
1917 static int sctp_process_inv_paramlength(const struct sctp_association *asoc,
1918                                         struct sctp_paramhdr *param,
1919                                         const struct sctp_chunk *chunk,
1920                                         struct sctp_chunk **errp)
1921 {
1922         /* This is a fatal error.  Any accumulated non-fatal errors are
1923          * not reported.
1924          */
1925         if (*errp)
1926                 sctp_chunk_free(*errp);
1927 
1928         /* Create an error chunk and fill it in with our payload. */
1929         *errp = sctp_make_violation_paramlen(asoc, chunk, param);
1930 
1931         return 0;
1932 }
1933 
1934 
1935 /* Do not attempt to handle the HOST_NAME parm.  However, do
1936  * send back an indicator to the peer.
1937  */
1938 static int sctp_process_hn_param(const struct sctp_association *asoc,
1939                                  union sctp_params param,
1940                                  struct sctp_chunk *chunk,
1941                                  struct sctp_chunk **errp)
1942 {
1943         __u16 len = ntohs(param.p->length);
1944 
1945         /* Processing of the HOST_NAME parameter will generate an
1946          * ABORT.  If we've accumulated any non-fatal errors, they
1947          * would be unrecognized parameters and we should not include
1948          * them in the ABORT.
1949          */
1950         if (*errp)
1951                 sctp_chunk_free(*errp);
1952 
1953         *errp = sctp_make_op_error_space(asoc, chunk, len);
1954 
1955         if (*errp) {
1956                 sctp_init_cause(*errp, SCTP_ERROR_DNS_FAILED, len);
1957                 sctp_addto_chunk(*errp, len, param.v);
1958         }
1959 
1960         /* Stop processing this chunk. */
1961         return 0;
1962 }
1963 
1964 static int sctp_verify_ext_param(struct net *net, union sctp_params param)
1965 {
1966         __u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
1967         int have_auth = 0;
1968         int have_asconf = 0;
1969         int i;
1970 
1971         for (i = 0; i < num_ext; i++) {
1972                 switch (param.ext->chunks[i]) {
1973                 case SCTP_CID_AUTH:
1974                         have_auth = 1;
1975                         break;
1976                 case SCTP_CID_ASCONF:
1977                 case SCTP_CID_ASCONF_ACK:
1978                         have_asconf = 1;
1979                         break;
1980                 }
1981         }
1982 
1983         /* ADD-IP Security: The draft requires us to ABORT or ignore the
1984          * INIT/INIT-ACK if ADD-IP is listed, but AUTH is not.  Do this
1985          * only if ADD-IP is turned on and we are not backward-compatible
1986          * mode.
1987          */
1988         if (net->sctp.addip_noauth)
1989                 return 1;
1990 
1991         if (net->sctp.addip_enable && !have_auth && have_asconf)
1992                 return 0;
1993 
1994         return 1;
1995 }
1996 
1997 static void sctp_process_ext_param(struct sctp_association *asoc,
1998                                     union sctp_params param)
1999 {
2000         struct net *net = sock_net(asoc->base.sk);
2001         __u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2002         int i;
2003 
2004         for (i = 0; i < num_ext; i++) {
2005                 switch (param.ext->chunks[i]) {
2006                 case SCTP_CID_FWD_TSN:
2007                         if (net->sctp.prsctp_enable && !asoc->peer.prsctp_capable)
2008                                     asoc->peer.prsctp_capable = 1;
2009                         break;
2010                 case SCTP_CID_AUTH:
2011                         /* if the peer reports AUTH, assume that he
2012                          * supports AUTH.
2013                          */
2014                         if (asoc->ep->auth_enable)
2015                                 asoc->peer.auth_capable = 1;
2016                         break;
2017                 case SCTP_CID_ASCONF:
2018                 case SCTP_CID_ASCONF_ACK:
2019                         if (net->sctp.addip_enable)
2020                                 asoc->peer.asconf_capable = 1;
2021                         break;
2022                 default:
2023                         break;
2024                 }
2025         }
2026 }
2027 
2028 /* RFC 3.2.1 & the Implementers Guide 2.2.
2029  *
2030  * The Parameter Types are encoded such that the
2031  * highest-order two bits specify the action that must be
2032  * taken if the processing endpoint does not recognize the
2033  * Parameter Type.
2034  *
2035  * 00 - Stop processing this parameter; do not process any further
2036  *      parameters within this chunk
2037  *
2038  * 01 - Stop processing this parameter, do not process any further
2039  *      parameters within this chunk, and report the unrecognized
2040  *      parameter in an 'Unrecognized Parameter' ERROR chunk.
2041  *
2042  * 10 - Skip this parameter and continue processing.
2043  *
2044  * 11 - Skip this parameter and continue processing but
2045  *      report the unrecognized parameter in an
2046  *      'Unrecognized Parameter' ERROR chunk.
2047  *
2048  * Return value:
2049  *      SCTP_IERROR_NO_ERROR - continue with the chunk
2050  *      SCTP_IERROR_ERROR    - stop and report an error.
2051  *      SCTP_IERROR_NOMEME   - out of memory.
2052  */
2053 static sctp_ierror_t sctp_process_unk_param(const struct sctp_association *asoc,
2054                                             union sctp_params param,
2055                                             struct sctp_chunk *chunk,
2056                                             struct sctp_chunk **errp)
2057 {
2058         int retval = SCTP_IERROR_NO_ERROR;
2059 
2060         switch (param.p->type & SCTP_PARAM_ACTION_MASK) {
2061         case SCTP_PARAM_ACTION_DISCARD:
2062                 retval =  SCTP_IERROR_ERROR;
2063                 break;
2064         case SCTP_PARAM_ACTION_SKIP:
2065                 break;
2066         case SCTP_PARAM_ACTION_DISCARD_ERR:
2067                 retval =  SCTP_IERROR_ERROR;
2068                 /* Fall through */
2069         case SCTP_PARAM_ACTION_SKIP_ERR:
2070                 /* Make an ERROR chunk, preparing enough room for
2071                  * returning multiple unknown parameters.
2072                  */
2073                 if (NULL == *errp)
2074                         *errp = sctp_make_op_error_fixed(asoc, chunk);
2075 
2076                 if (*errp) {
2077                         if (!sctp_init_cause_fixed(*errp, SCTP_ERROR_UNKNOWN_PARAM,
2078                                         WORD_ROUND(ntohs(param.p->length))))
2079                                 sctp_addto_chunk_fixed(*errp,
2080                                                 WORD_ROUND(ntohs(param.p->length)),
2081                                                 param.v);
2082                 } else {
2083                         /* If there is no memory for generating the ERROR
2084                          * report as specified, an ABORT will be triggered
2085                          * to the peer and the association won't be
2086                          * established.
2087                          */
2088                         retval = SCTP_IERROR_NOMEM;
2089                 }
2090                 break;
2091         default:
2092                 break;
2093         }
2094 
2095         return retval;
2096 }
2097 
2098 /* Verify variable length parameters
2099  * Return values:
2100  *      SCTP_IERROR_ABORT - trigger an ABORT
2101  *      SCTP_IERROR_NOMEM - out of memory (abort)
2102  *      SCTP_IERROR_ERROR - stop processing, trigger an ERROR
2103  *      SCTP_IERROR_NO_ERROR - continue with the chunk
2104  */
2105 static sctp_ierror_t sctp_verify_param(struct net *net,
2106                                         const struct sctp_endpoint *ep,
2107                                         const struct sctp_association *asoc,
2108                                         union sctp_params param,
2109                                         sctp_cid_t cid,
2110                                         struct sctp_chunk *chunk,
2111                                         struct sctp_chunk **err_chunk)
2112 {
2113         struct sctp_hmac_algo_param *hmacs;
2114         int retval = SCTP_IERROR_NO_ERROR;
2115         __u16 n_elt, id = 0;
2116         int i;
2117 
2118         /* FIXME - This routine is not looking at each parameter per the
2119          * chunk type, i.e., unrecognized parameters should be further
2120          * identified based on the chunk id.
2121          */
2122 
2123         switch (param.p->type) {
2124         case SCTP_PARAM_IPV4_ADDRESS:
2125         case SCTP_PARAM_IPV6_ADDRESS:
2126         case SCTP_PARAM_COOKIE_PRESERVATIVE:
2127         case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2128         case SCTP_PARAM_STATE_COOKIE:
2129         case SCTP_PARAM_HEARTBEAT_INFO:
2130         case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2131         case SCTP_PARAM_ECN_CAPABLE:
2132         case SCTP_PARAM_ADAPTATION_LAYER_IND:
2133                 break;
2134 
2135         case SCTP_PARAM_SUPPORTED_EXT:
2136                 if (!sctp_verify_ext_param(net, param))
2137                         return SCTP_IERROR_ABORT;
2138                 break;
2139 
2140         case SCTP_PARAM_SET_PRIMARY:
2141                 if (net->sctp.addip_enable)
2142                         break;
2143                 goto fallthrough;
2144 
2145         case SCTP_PARAM_HOST_NAME_ADDRESS:
2146                 /* Tell the peer, we won't support this param.  */
2147                 sctp_process_hn_param(asoc, param, chunk, err_chunk);
2148                 retval = SCTP_IERROR_ABORT;
2149                 break;
2150 
2151         case SCTP_PARAM_FWD_TSN_SUPPORT:
2152                 if (net->sctp.prsctp_enable)
2153                         break;
2154                 goto fallthrough;
2155 
2156         case SCTP_PARAM_RANDOM:
2157                 if (!ep->auth_enable)
2158                         goto fallthrough;
2159 
2160                 /* SCTP-AUTH: Secion 6.1
2161                  * If the random number is not 32 byte long the association
2162                  * MUST be aborted.  The ABORT chunk SHOULD contain the error
2163                  * cause 'Protocol Violation'.
2164                  */
2165                 if (SCTP_AUTH_RANDOM_LENGTH !=
2166                         ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) {
2167                         sctp_process_inv_paramlength(asoc, param.p,
2168                                                         chunk, err_chunk);
2169                         retval = SCTP_IERROR_ABORT;
2170                 }
2171                 break;
2172 
2173         case SCTP_PARAM_CHUNKS:
2174                 if (!ep->auth_enable)
2175                         goto fallthrough;
2176 
2177                 /* SCTP-AUTH: Section 3.2
2178                  * The CHUNKS parameter MUST be included once in the INIT or
2179                  *  INIT-ACK chunk if the sender wants to receive authenticated
2180                  *  chunks.  Its maximum length is 260 bytes.
2181                  */
2182                 if (260 < ntohs(param.p->length)) {
2183                         sctp_process_inv_paramlength(asoc, param.p,
2184                                                      chunk, err_chunk);
2185                         retval = SCTP_IERROR_ABORT;
2186                 }
2187                 break;
2188 
2189         case SCTP_PARAM_HMAC_ALGO:
2190                 if (!ep->auth_enable)
2191                         goto fallthrough;
2192 
2193                 hmacs = (struct sctp_hmac_algo_param *)param.p;
2194                 n_elt = (ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) >> 1;
2195 
2196                 /* SCTP-AUTH: Section 6.1
2197                  * The HMAC algorithm based on SHA-1 MUST be supported and
2198                  * included in the HMAC-ALGO parameter.
2199                  */
2200                 for (i = 0; i < n_elt; i++) {
2201                         id = ntohs(hmacs->hmac_ids[i]);
2202 
2203                         if (id == SCTP_AUTH_HMAC_ID_SHA1)
2204                                 break;
2205                 }
2206 
2207                 if (id != SCTP_AUTH_HMAC_ID_SHA1) {
2208                         sctp_process_inv_paramlength(asoc, param.p, chunk,
2209                                                      err_chunk);
2210                         retval = SCTP_IERROR_ABORT;
2211                 }
2212                 break;
2213 fallthrough:
2214         default:
2215                 pr_debug("%s: unrecognized param:%d for chunk:%d\n",
2216                          __func__, ntohs(param.p->type), cid);
2217 
2218                 retval = sctp_process_unk_param(asoc, param, chunk, err_chunk);
2219                 break;
2220         }
2221         return retval;
2222 }
2223 
2224 /* Verify the INIT packet before we process it.  */
2225 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
2226                      const struct sctp_association *asoc, sctp_cid_t cid,
2227                      sctp_init_chunk_t *peer_init, struct sctp_chunk *chunk,
2228                      struct sctp_chunk **errp)
2229 {
2230         union sctp_params param;
2231         bool has_cookie = false;
2232         int result;
2233 
2234         /* Check for missing mandatory parameters. Note: Initial TSN is
2235          * also mandatory, but is not checked here since the valid range
2236          * is 0..2**32-1. RFC4960, section 3.3.3.
2237          */
2238         if (peer_init->init_hdr.num_outbound_streams == 0 ||
2239             peer_init->init_hdr.num_inbound_streams == 0 ||
2240             peer_init->init_hdr.init_tag == 0 ||
2241             ntohl(peer_init->init_hdr.a_rwnd) < SCTP_DEFAULT_MINWINDOW)
2242                 return sctp_process_inv_mandatory(asoc, chunk, errp);
2243 
2244         sctp_walk_params(param, peer_init, init_hdr.params) {
2245                 if (param.p->type == SCTP_PARAM_STATE_COOKIE)
2246                         has_cookie = true;
2247         }
2248 
2249         /* There is a possibility that a parameter length was bad and
2250          * in that case we would have stoped walking the parameters.
2251          * The current param.p would point at the bad one.
2252          * Current consensus on the mailing list is to generate a PROTOCOL
2253          * VIOLATION error.  We build the ERROR chunk here and let the normal
2254          * error handling code build and send the packet.
2255          */
2256         if (param.v != (void *)chunk->chunk_end)
2257                 return sctp_process_inv_paramlength(asoc, param.p, chunk, errp);
2258 
2259         /* The only missing mandatory param possible today is
2260          * the state cookie for an INIT-ACK chunk.
2261          */
2262         if ((SCTP_CID_INIT_ACK == cid) && !has_cookie)
2263                 return sctp_process_missing_param(asoc, SCTP_PARAM_STATE_COOKIE,
2264                                                   chunk, errp);
2265 
2266         /* Verify all the variable length parameters */
2267         sctp_walk_params(param, peer_init, init_hdr.params) {
2268                 result = sctp_verify_param(net, ep, asoc, param, cid,
2269                                            chunk, errp);
2270                 switch (result) {
2271                 case SCTP_IERROR_ABORT:
2272                 case SCTP_IERROR_NOMEM:
2273                         return 0;
2274                 case SCTP_IERROR_ERROR:
2275                         return 1;
2276                 case SCTP_IERROR_NO_ERROR:
2277                 default:
2278                         break;
2279                 }
2280 
2281         } /* for (loop through all parameters) */
2282 
2283         return 1;
2284 }
2285 
2286 /* Unpack the parameters in an INIT packet into an association.
2287  * Returns 0 on failure, else success.
2288  * FIXME:  This is an association method.
2289  */
2290 int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,
2291                       const union sctp_addr *peer_addr,
2292                       sctp_init_chunk_t *peer_init, gfp_t gfp)
2293 {
2294         struct net *net = sock_net(asoc->base.sk);
2295         union sctp_params param;
2296         struct sctp_transport *transport;
2297         struct list_head *pos, *temp;
2298         struct sctp_af *af;
2299         union sctp_addr addr;
2300         char *cookie;
2301         int src_match = 0;
2302 
2303         /* We must include the address that the INIT packet came from.
2304          * This is the only address that matters for an INIT packet.
2305          * When processing a COOKIE ECHO, we retrieve the from address
2306          * of the INIT from the cookie.
2307          */
2308 
2309         /* This implementation defaults to making the first transport
2310          * added as the primary transport.  The source address seems to
2311          * be a a better choice than any of the embedded addresses.
2312          */
2313         if (!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
2314                 goto nomem;
2315 
2316         if (sctp_cmp_addr_exact(sctp_source(chunk), peer_addr))
2317                 src_match = 1;
2318 
2319         /* Process the initialization parameters.  */
2320         sctp_walk_params(param, peer_init, init_hdr.params) {
2321                 if (!src_match && (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
2322                     param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
2323                         af = sctp_get_af_specific(param_type2af(param.p->type));
2324                         af->from_addr_param(&addr, param.addr,
2325                                             chunk->sctp_hdr->source, 0);
2326                         if (sctp_cmp_addr_exact(sctp_source(chunk), &addr))
2327                                 src_match = 1;
2328                 }
2329 
2330                 if (!sctp_process_param(asoc, param, peer_addr, gfp))
2331                         goto clean_up;
2332         }
2333 
2334         /* source address of chunk may not match any valid address */
2335         if (!src_match)
2336                 goto clean_up;
2337 
2338         /* AUTH: After processing the parameters, make sure that we
2339          * have all the required info to potentially do authentications.
2340          */
2341         if (asoc->peer.auth_capable && (!asoc->peer.peer_random ||
2342                                         !asoc->peer.peer_hmacs))
2343                 asoc->peer.auth_capable = 0;
2344 
2345         /* In a non-backward compatible mode, if the peer claims
2346          * support for ADD-IP but not AUTH,  the ADD-IP spec states
2347          * that we MUST ABORT the association. Section 6.  The section
2348          * also give us an option to silently ignore the packet, which
2349          * is what we'll do here.
2350          */
2351         if (!net->sctp.addip_noauth &&
2352              (asoc->peer.asconf_capable && !asoc->peer.auth_capable)) {
2353                 asoc->peer.addip_disabled_mask |= (SCTP_PARAM_ADD_IP |
2354                                                   SCTP_PARAM_DEL_IP |
2355                                                   SCTP_PARAM_SET_PRIMARY);
2356                 asoc->peer.asconf_capable = 0;
2357                 goto clean_up;
2358         }
2359 
2360         /* Walk list of transports, removing transports in the UNKNOWN state. */
2361         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2362                 transport = list_entry(pos, struct sctp_transport, transports);
2363                 if (transport->state == SCTP_UNKNOWN) {
2364                         sctp_assoc_rm_peer(asoc, transport);
2365                 }
2366         }
2367 
2368         /* The fixed INIT headers are always in network byte
2369          * order.
2370          */
2371         asoc->peer.i.init_tag =
2372                 ntohl(peer_init->init_hdr.init_tag);
2373         asoc->peer.i.a_rwnd =
2374                 ntohl(peer_init->init_hdr.a_rwnd);
2375         asoc->peer.i.num_outbound_streams =
2376                 ntohs(peer_init->init_hdr.num_outbound_streams);
2377         asoc->peer.i.num_inbound_streams =
2378                 ntohs(peer_init->init_hdr.num_inbound_streams);
2379         asoc->peer.i.initial_tsn =
2380                 ntohl(peer_init->init_hdr.initial_tsn);
2381 
2382         /* Apply the upper bounds for output streams based on peer's
2383          * number of inbound streams.
2384          */
2385         if (asoc->c.sinit_num_ostreams  >
2386             ntohs(peer_init->init_hdr.num_inbound_streams)) {
2387                 asoc->c.sinit_num_ostreams =
2388                         ntohs(peer_init->init_hdr.num_inbound_streams);
2389         }
2390 
2391         if (asoc->c.sinit_max_instreams >
2392             ntohs(peer_init->init_hdr.num_outbound_streams)) {
2393                 asoc->c.sinit_max_instreams =
2394                         ntohs(peer_init->init_hdr.num_outbound_streams);
2395         }
2396 
2397         /* Copy Initiation tag from INIT to VT_peer in cookie.   */
2398         asoc->c.peer_vtag = asoc->peer.i.init_tag;
2399 
2400         /* Peer Rwnd   : Current calculated value of the peer's rwnd.  */
2401         asoc->peer.rwnd = asoc->peer.i.a_rwnd;
2402 
2403         /* Copy cookie in case we need to resend COOKIE-ECHO. */
2404         cookie = asoc->peer.cookie;
2405         if (cookie) {
2406                 asoc->peer.cookie = kmemdup(cookie, asoc->peer.cookie_len, gfp);
2407                 if (!asoc->peer.cookie)
2408                         goto clean_up;
2409         }
2410 
2411         /* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily
2412          * high (for example, implementations MAY use the size of the receiver
2413          * advertised window).
2414          */
2415         list_for_each_entry(transport, &asoc->peer.transport_addr_list,
2416                         transports) {
2417                 transport->ssthresh = asoc->peer.i.a_rwnd;
2418         }
2419 
2420         /* Set up the TSN tracking pieces.  */
2421         if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
2422                                 asoc->peer.i.initial_tsn, gfp))
2423                 goto clean_up;
2424 
2425         /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
2426          *
2427          * The stream sequence number in all the streams shall start
2428          * from 0 when the association is established.  Also, when the
2429          * stream sequence number reaches the value 65535 the next
2430          * stream sequence number shall be set to 0.
2431          */
2432 
2433         /* Allocate storage for the negotiated streams if it is not a temporary
2434          * association.
2435          */
2436         if (!asoc->temp) {
2437                 int error;
2438 
2439                 asoc->ssnmap = sctp_ssnmap_new(asoc->c.sinit_max_instreams,
2440                                                asoc->c.sinit_num_ostreams, gfp);
2441                 if (!asoc->ssnmap)
2442                         goto clean_up;
2443 
2444                 error = sctp_assoc_set_id(asoc, gfp);
2445                 if (error)
2446                         goto clean_up;
2447         }
2448 
2449         /* ADDIP Section 4.1 ASCONF Chunk Procedures
2450          *
2451          * When an endpoint has an ASCONF signaled change to be sent to the
2452          * remote endpoint it should do the following:
2453          * ...
2454          * A2) A serial number should be assigned to the Chunk. The serial
2455          * number should be a monotonically increasing number. All serial
2456          * numbers are defined to be initialized at the start of the
2457          * association to the same value as the Initial TSN.
2458          */
2459         asoc->peer.addip_serial = asoc->peer.i.initial_tsn - 1;
2460         return 1;
2461 
2462 clean_up:
2463         /* Release the transport structures. */
2464         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2465                 transport = list_entry(pos, struct sctp_transport, transports);
2466                 if (transport->state != SCTP_ACTIVE)
2467                         sctp_assoc_rm_peer(asoc, transport);
2468         }
2469 
2470 nomem:
2471         return 0;
2472 }
2473 
2474 
2475 /* Update asoc with the option described in param.
2476  *
2477  * RFC2960 3.3.2.1 Optional/Variable Length Parameters in INIT
2478  *
2479  * asoc is the association to update.
2480  * param is the variable length parameter to use for update.
2481  * cid tells us if this is an INIT, INIT ACK or COOKIE ECHO.
2482  * If the current packet is an INIT we want to minimize the amount of
2483  * work we do.  In particular, we should not build transport
2484  * structures for the addresses.
2485  */
2486 static int sctp_process_param(struct sctp_association *asoc,
2487                               union sctp_params param,
2488                               const union sctp_addr *peer_addr,
2489                               gfp_t gfp)
2490 {
2491         struct net *net = sock_net(asoc->base.sk);
2492         union sctp_addr addr;
2493         int i;
2494         __u16 sat;
2495         int retval = 1;
2496         sctp_scope_t scope;
2497         time_t stale;
2498         struct sctp_af *af;
2499         union sctp_addr_param *addr_param;
2500         struct sctp_transport *t;
2501         struct sctp_endpoint *ep = asoc->ep;
2502 
2503         /* We maintain all INIT parameters in network byte order all the
2504          * time.  This allows us to not worry about whether the parameters
2505          * came from a fresh INIT, and INIT ACK, or were stored in a cookie.
2506          */
2507         switch (param.p->type) {
2508         case SCTP_PARAM_IPV6_ADDRESS:
2509                 if (PF_INET6 != asoc->base.sk->sk_family)
2510                         break;
2511                 goto do_addr_param;
2512 
2513         case SCTP_PARAM_IPV4_ADDRESS:
2514                 /* v4 addresses are not allowed on v6-only socket */
2515                 if (ipv6_only_sock(asoc->base.sk))
2516                         break;
2517 do_addr_param:
2518                 af = sctp_get_af_specific(param_type2af(param.p->type));
2519                 af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
2520                 scope = sctp_scope(peer_addr);
2521                 if (sctp_in_scope(net, &addr, scope))
2522                         if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
2523                                 return 0;
2524                 break;
2525 
2526         case SCTP_PARAM_COOKIE_PRESERVATIVE:
2527                 if (!net->sctp.cookie_preserve_enable)
2528                         break;
2529 
2530                 stale = ntohl(param.life->lifespan_increment);
2531 
2532                 /* Suggested Cookie Life span increment's unit is msec,
2533                  * (1/1000sec).
2534                  */
2535                 asoc->cookie_life = ktime_add_ms(asoc->cookie_life, stale);
2536                 break;
2537 
2538         case SCTP_PARAM_HOST_NAME_ADDRESS:
2539                 pr_debug("%s: unimplemented SCTP_HOST_NAME_ADDRESS\n", __func__);
2540                 break;
2541 
2542         case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2543                 /* Turn off the default values first so we'll know which
2544                  * ones are really set by the peer.
2545                  */
2546                 asoc->peer.ipv4_address = 0;
2547                 asoc->peer.ipv6_address = 0;
2548 
2549                 /* Assume that peer supports the address family
2550                  * by which it sends a packet.
2551                  */
2552                 if (peer_addr->sa.sa_family == AF_INET6)
2553                         asoc->peer.ipv6_address = 1;
2554                 else if (peer_addr->sa.sa_family == AF_INET)
2555                         asoc->peer.ipv4_address = 1;
2556 
2557                 /* Cycle through address types; avoid divide by 0. */
2558                 sat = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2559                 if (sat)
2560                         sat /= sizeof(__u16);
2561 
2562                 for (i = 0; i < sat; ++i) {
2563                         switch (param.sat->types[i]) {
2564                         case SCTP_PARAM_IPV4_ADDRESS:
2565                                 asoc->peer.ipv4_address = 1;
2566                                 break;
2567 
2568                         case SCTP_PARAM_IPV6_ADDRESS:
2569                                 if (PF_INET6 == asoc->base.sk->sk_family)
2570                                         asoc->peer.ipv6_address = 1;
2571                                 break;
2572 
2573                         case SCTP_PARAM_HOST_NAME_ADDRESS:
2574                                 asoc->peer.hostname_address = 1;
2575                                 break;
2576 
2577                         default: /* Just ignore anything else.  */
2578                                 break;
2579                         }
2580                 }
2581                 break;
2582 
2583         case SCTP_PARAM_STATE_COOKIE:
2584                 asoc->peer.cookie_len =
2585                         ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2586                 asoc->peer.cookie = param.cookie->body;
2587                 break;
2588 
2589         case SCTP_PARAM_HEARTBEAT_INFO:
2590                 /* Would be odd to receive, but it causes no problems. */
2591                 break;
2592 
2593         case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2594                 /* Rejected during verify stage. */
2595                 break;
2596 
2597         case SCTP_PARAM_ECN_CAPABLE:
2598                 asoc->peer.ecn_capable = 1;
2599                 break;
2600 
2601         case SCTP_PARAM_ADAPTATION_LAYER_IND:
2602                 asoc->peer.adaptation_ind = ntohl(param.aind->adaptation_ind);
2603                 break;
2604 
2605         case SCTP_PARAM_SET_PRIMARY:
2606                 if (!net->sctp.addip_enable)
2607                         goto fall_through;
2608 
2609                 addr_param = param.v + sizeof(sctp_addip_param_t);
2610 
2611                 af = sctp_get_af_specific(param_type2af(addr_param->p.type));
2612                 if (af == NULL)
2613                         break;
2614 
2615                 af->from_addr_param(&addr, addr_param,
2616                                     htons(asoc->peer.port), 0);
2617 
2618                 /* if the address is invalid, we can't process it.
2619                  * XXX: see spec for what to do.
2620                  */
2621                 if (!af->addr_valid(&addr, NULL, NULL))
2622                         break;
2623 
2624                 t = sctp_assoc_lookup_paddr(asoc, &addr);
2625                 if (!t)
2626                         break;
2627 
2628                 sctp_assoc_set_primary(asoc, t);
2629                 break;
2630 
2631         case SCTP_PARAM_SUPPORTED_EXT:
2632                 sctp_process_ext_param(asoc, param);
2633                 break;
2634 
2635         case SCTP_PARAM_FWD_TSN_SUPPORT:
2636                 if (net->sctp.prsctp_enable) {
2637                         asoc->peer.prsctp_capable = 1;
2638                         break;
2639                 }
2640                 /* Fall Through */
2641                 goto fall_through;
2642 
2643         case SCTP_PARAM_RANDOM:
2644                 if (!ep->auth_enable)
2645                         goto fall_through;
2646 
2647                 /* Save peer's random parameter */
2648                 asoc->peer.peer_random = kmemdup(param.p,
2649                                             ntohs(param.p->length), gfp);
2650                 if (!asoc->peer.peer_random) {
2651                         retval = 0;
2652                         break;
2653                 }
2654                 break;
2655 
2656         case SCTP_PARAM_HMAC_ALGO:
2657                 if (!ep->auth_enable)
2658                         goto fall_through;
2659 
2660                 /* Save peer's HMAC list */
2661                 asoc->peer.peer_hmacs = kmemdup(param.p,
2662                                             ntohs(param.p->length), gfp);
2663                 if (!asoc->peer.peer_hmacs) {
2664                         retval = 0;
2665                         break;
2666                 }
2667 
2668                 /* Set the default HMAC the peer requested*/
2669                 sctp_auth_asoc_set_default_hmac(asoc, param.hmac_algo);
2670                 break;
2671 
2672         case SCTP_PARAM_CHUNKS:
2673                 if (!ep->auth_enable)
2674                         goto fall_through;
2675 
2676                 asoc->peer.peer_chunks = kmemdup(param.p,
2677                                             ntohs(param.p->length), gfp);
2678                 if (!asoc->peer.peer_chunks)
2679                         retval = 0;
2680                 break;
2681 fall_through:
2682         default:
2683                 /* Any unrecognized parameters should have been caught
2684                  * and handled by sctp_verify_param() which should be
2685                  * called prior to this routine.  Simply log the error
2686                  * here.
2687                  */
2688                 pr_debug("%s: ignoring param:%d for association:%p.\n",
2689                          __func__, ntohs(param.p->type), asoc);
2690                 break;
2691         }
2692 
2693         return retval;
2694 }
2695 
2696 /* Select a new verification tag.  */
2697 __u32 sctp_generate_tag(const struct sctp_endpoint *ep)
2698 {
2699         /* I believe that this random number generator complies with RFC1750.
2700          * A tag of 0 is reserved for special cases (e.g. INIT).
2701          */
2702         __u32 x;
2703 
2704         do {
2705                 get_random_bytes(&x, sizeof(__u32));
2706         } while (x == 0);
2707 
2708         return x;
2709 }
2710 
2711 /* Select an initial TSN to send during startup.  */
2712 __u32 sctp_generate_tsn(const struct sctp_endpoint *ep)
2713 {
2714         __u32 retval;
2715 
2716         get_random_bytes(&retval, sizeof(__u32));
2717         return retval;
2718 }
2719 
2720 /*
2721  * ADDIP 3.1.1 Address Configuration Change Chunk (ASCONF)
2722  *      0                   1                   2                   3
2723  *      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
2724  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2725  *     | Type = 0xC1   |  Chunk Flags  |      Chunk Length             |
2726  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2727  *     |                       Serial Number                           |
2728  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2729  *     |                    Address Parameter                          |
2730  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2731  *     |                     ASCONF Parameter #1                       |
2732  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2733  *     \                                                               \
2734  *     /                             ....                              /
2735  *     \                                                               \
2736  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2737  *     |                     ASCONF Parameter #N                       |
2738  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2739  *
2740  * Address Parameter and other parameter will not be wrapped in this function
2741  */
2742 static struct sctp_chunk *sctp_make_asconf(struct sctp_association *asoc,
2743                                            union sctp_addr *addr,
2744                                            int vparam_len)
2745 {
2746         sctp_addiphdr_t asconf;
2747         struct sctp_chunk *retval;
2748         int length = sizeof(asconf) + vparam_len;
2749         union sctp_addr_param addrparam;
2750         int addrlen;
2751         struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
2752 
2753         addrlen = af->to_addr_param(addr, &addrparam);
2754         if (!addrlen)
2755                 return NULL;
2756         length += addrlen;
2757 
2758         /* Create the chunk.  */
2759         retval = sctp_make_control(asoc, SCTP_CID_ASCONF, 0, length);
2760         if (!retval)
2761                 return NULL;
2762 
2763         asconf.serial = htonl(asoc->addip_serial++);
2764 
2765         retval->subh.addip_hdr =
2766                 sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2767         retval->param_hdr.v =
2768                 sctp_addto_chunk(retval, addrlen, &addrparam);
2769 
2770         return retval;
2771 }
2772 
2773 /* ADDIP
2774  * 3.2.1 Add IP Address
2775  *      0                   1                   2                   3
2776  *      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
2777  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2778  *     |        Type = 0xC001          |    Length = Variable          |
2779  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2780  *     |               ASCONF-Request Correlation ID                   |
2781  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2782  *     |                       Address Parameter                       |
2783  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2784  *
2785  * 3.2.2 Delete IP Address
2786  *      0                   1                   2                   3
2787  *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
2788  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2789  *     |        Type = 0xC002          |    Length = Variable          |
2790  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2791  *     |               ASCONF-Request Correlation ID                   |
2792  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2793  *     |                       Address Parameter                       |
2794  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2795  *
2796  */
2797 struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *asoc,
2798                                               union sctp_addr         *laddr,
2799                                               struct sockaddr         *addrs,
2800                                               int                     addrcnt,
2801                                               __be16                  flags)
2802 {
2803         sctp_addip_param_t      param;
2804         struct sctp_chunk       *retval;
2805         union sctp_addr_param   addr_param;
2806         union sctp_addr         *addr;
2807         void                    *addr_buf;
2808         struct sctp_af          *af;
2809         int                     paramlen = sizeof(param);
2810         int                     addr_param_len = 0;
2811         int                     totallen = 0;
2812         int                     i;
2813         int                     del_pickup = 0;
2814 
2815         /* Get total length of all the address parameters. */
2816         addr_buf = addrs;
2817         for (i = 0; i < addrcnt; i++) {
2818                 addr = addr_buf;
2819                 af = sctp_get_af_specific(addr->v4.sin_family);
2820                 addr_param_len = af->to_addr_param(addr, &addr_param);
2821 
2822                 totallen += paramlen;
2823                 totallen += addr_param_len;
2824 
2825                 addr_buf += af->sockaddr_len;
2826                 if (asoc->asconf_addr_del_pending && !del_pickup) {
2827                         /* reuse the parameter length from the same scope one */
2828                         totallen += paramlen;
2829                         totallen += addr_param_len;
2830                         del_pickup = 1;
2831 
2832                         pr_debug("%s: picked same-scope del_pending addr, "
2833                                  "totallen for all addresses is %d\n",
2834                                  __func__, totallen);
2835                 }
2836         }
2837 
2838         /* Create an asconf chunk with the required length. */
2839         retval = sctp_make_asconf(asoc, laddr, totallen);
2840         if (!retval)
2841                 return NULL;
2842 
2843         /* Add the address parameters to the asconf chunk. */
2844         addr_buf = addrs;
2845         for (i = 0; i < addrcnt; i++) {
2846                 addr = addr_buf;
2847                 af = sctp_get_af_specific(addr->v4.sin_family);
2848                 addr_param_len = af->to_addr_param(addr, &addr_param);
2849                 param.param_hdr.type = flags;
2850                 param.param_hdr.length = htons(paramlen + addr_param_len);
2851                 param.crr_id = i;
2852 
2853                 sctp_addto_chunk(retval, paramlen, &param);
2854                 sctp_addto_chunk(retval, addr_param_len, &addr_param);
2855 
2856                 addr_buf += af->sockaddr_len;
2857         }
2858         if (flags == SCTP_PARAM_ADD_IP && del_pickup) {
2859                 addr = asoc->asconf_addr_del_pending;
2860                 af = sctp_get_af_specific(addr->v4.sin_family);
2861                 addr_param_len = af->to_addr_param(addr, &addr_param);
2862                 param.param_hdr.type = SCTP_PARAM_DEL_IP;
2863                 param.param_hdr.length = htons(paramlen + addr_param_len);
2864                 param.crr_id = i;
2865 
2866                 sctp_addto_chunk(retval, paramlen, &param);
2867                 sctp_addto_chunk(retval, addr_param_len, &addr_param);
2868         }
2869         return retval;
2870 }
2871 
2872 /* ADDIP
2873  * 3.2.4 Set Primary IP Address
2874  *      0                   1                   2                   3
2875  *      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
2876  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2877  *     |        Type =0xC004           |    Length = Variable          |
2878  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2879  *     |               ASCONF-Request Correlation ID                   |
2880  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2881  *     |                       Address Parameter                       |
2882  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2883  *
2884  * Create an ASCONF chunk with Set Primary IP address parameter.
2885  */
2886 struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
2887                                              union sctp_addr *addr)
2888 {
2889         sctp_addip_param_t      param;
2890         struct sctp_chunk       *retval;
2891         int                     len = sizeof(param);
2892         union sctp_addr_param   addrparam;
2893         int                     addrlen;
2894         struct sctp_af          *af = sctp_get_af_specific(addr->v4.sin_family);
2895 
2896         addrlen = af->to_addr_param(addr, &addrparam);
2897         if (!addrlen)
2898                 return NULL;
2899         len += addrlen;
2900 
2901         /* Create the chunk and make asconf header. */
2902         retval = sctp_make_asconf(asoc, addr, len);
2903         if (!retval)
2904                 return NULL;
2905 
2906         param.param_hdr.type = SCTP_PARAM_SET_PRIMARY;
2907         param.param_hdr.length = htons(len);
2908         param.crr_id = 0;
2909 
2910         sctp_addto_chunk(retval, sizeof(param), &param);
2911         sctp_addto_chunk(retval, addrlen, &addrparam);
2912 
2913         return retval;
2914 }
2915 
2916 /* ADDIP 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
2917  *      0                   1                   2                   3
2918  *      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
2919  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2920  *     | Type = 0x80   |  Chunk Flags  |      Chunk Length             |
2921  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2922  *     |                       Serial Number                           |
2923  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2924  *     |                 ASCONF Parameter Response#1                   |
2925  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2926  *     \                                                               \
2927  *     /                             ....                              /
2928  *     \                                                               \
2929  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2930  *     |                 ASCONF Parameter Response#N                   |
2931  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2932  *
2933  * Create an ASCONF_ACK chunk with enough space for the parameter responses.
2934  */
2935 static struct sctp_chunk *sctp_make_asconf_ack(const struct sctp_association *asoc,
2936                                                __u32 serial, int vparam_len)
2937 {
2938         sctp_addiphdr_t         asconf;
2939         struct sctp_chunk       *retval;
2940         int                     length = sizeof(asconf) + vparam_len;
2941 
2942         /* Create the chunk.  */
2943         retval = sctp_make_control(asoc, SCTP_CID_ASCONF_ACK, 0, length);
2944         if (!retval)
2945                 return NULL;
2946 
2947         asconf.serial = htonl(serial);
2948 
2949         retval->subh.addip_hdr =
2950                 sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2951 
2952         return retval;
2953 }
2954 
2955 /* Add response parameters to an ASCONF_ACK chunk. */
2956 static void sctp_add_asconf_response(struct sctp_chunk *chunk, __be32 crr_id,
2957                               __be16 err_code, sctp_addip_param_t *asconf_param)
2958 {
2959         sctp_addip_param_t      ack_param;
2960         sctp_errhdr_t           err_param;
2961         int                     asconf_param_len = 0;
2962         int                     err_param_len = 0;
2963         __be16                  response_type;
2964 
2965         if (SCTP_ERROR_NO_ERROR == err_code) {
2966                 response_type = SCTP_PARAM_SUCCESS_REPORT;
2967         } else {
2968                 response_type = SCTP_PARAM_ERR_CAUSE;
2969                 err_param_len = sizeof(err_param);
2970                 if (asconf_param)
2971                         asconf_param_len =
2972                                  ntohs(asconf_param->param_hdr.length);
2973         }
2974 
2975         /* Add Success Indication or Error Cause Indication parameter. */
2976         ack_param.param_hdr.type = response_type;
2977         ack_param.param_hdr.length = htons(sizeof(ack_param) +
2978                                            err_param_len +
2979                                            asconf_param_len);
2980         ack_param.crr_id = crr_id;
2981         sctp_addto_chunk(chunk, sizeof(ack_param), &ack_param);
2982 
2983         if (SCTP_ERROR_NO_ERROR == err_code)
2984                 return;
2985 
2986         /* Add Error Cause parameter. */
2987         err_param.cause = err_code;
2988         err_param.length = htons(err_param_len + asconf_param_len);
2989         sctp_addto_chunk(chunk, err_param_len, &err_param);
2990 
2991         /* Add the failed TLV copied from ASCONF chunk. */
2992         if (asconf_param)
2993                 sctp_addto_chunk(chunk, asconf_param_len, asconf_param);
2994 }
2995 
2996 /* Process a asconf parameter. */
2997 static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
2998                                        struct sctp_chunk *asconf,
2999                                        sctp_addip_param_t *asconf_param)
3000 {
3001         struct sctp_transport *peer;
3002         struct sctp_af *af;
3003         union sctp_addr addr;
3004         union sctp_addr_param *addr_param;
3005 
3006         addr_param = (void *)asconf_param + sizeof(sctp_addip_param_t);
3007 
3008         if (asconf_param->param_hdr.type != SCTP_PARAM_ADD_IP &&
3009             asconf_param->param_hdr.type != SCTP_PARAM_DEL_IP &&
3010             asconf_param->param_hdr.type != SCTP_PARAM_SET_PRIMARY)
3011                 return SCTP_ERROR_UNKNOWN_PARAM;
3012 
3013         switch (addr_param->p.type) {
3014         case SCTP_PARAM_IPV6_ADDRESS:
3015                 if (!asoc->peer.ipv6_address)
3016                         return SCTP_ERROR_DNS_FAILED;
3017                 break;
3018         case SCTP_PARAM_IPV4_ADDRESS:
3019                 if (!asoc->peer.ipv4_address)
3020                         return SCTP_ERROR_DNS_FAILED;
3021                 break;
3022         default:
3023                 return SCTP_ERROR_DNS_FAILED;
3024         }
3025 
3026         af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3027         if (unlikely(!af))
3028                 return SCTP_ERROR_DNS_FAILED;
3029 
3030         af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);
3031 
3032         /* ADDIP 4.2.1  This parameter MUST NOT contain a broadcast
3033          * or multicast address.
3034          * (note: wildcard is permitted and requires special handling so
3035          *  make sure we check for that)
3036          */
3037         if (!af->is_any(&addr) && !af->addr_valid(&addr, NULL, asconf->skb))
3038                 return SCTP_ERROR_DNS_FAILED;
3039 
3040         switch (asconf_param->param_hdr.type) {
3041         case SCTP_PARAM_ADD_IP:
3042                 /* Section 4.2.1:
3043                  * If the address 0.0.0.0 or ::0 is provided, the source
3044                  * address of the packet MUST be added.
3045                  */
3046                 if (af->is_any(&addr))
3047                         memcpy(&addr, &asconf->source, sizeof(addr));
3048 
3049                 /* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
3050                  * request and does not have the local resources to add this
3051                  * new address to the association, it MUST return an Error
3052                  * Cause TLV set to the new error code 'Operation Refused
3053                  * Due to Resource Shortage'.
3054                  */
3055 
3056                 peer = sctp_assoc_add_peer(asoc, &addr, GFP_ATOMIC, SCTP_UNCONFIRMED);
3057                 if (!peer)
3058                         return SCTP_ERROR_RSRC_LOW;
3059 
3060                 /* Start the heartbeat timer. */
3061                 if (!mod_timer(&peer->hb_timer, sctp_transport_timeout(peer)))
3062                         sctp_transport_hold(peer);
3063                 asoc->new_transport = peer;
3064                 break;
3065         case SCTP_PARAM_DEL_IP:
3066                 /* ADDIP 4.3 D7) If a request is received to delete the
3067                  * last remaining IP address of a peer endpoint, the receiver
3068                  * MUST send an Error Cause TLV with the error cause set to the
3069                  * new error code 'Request to Delete Last Remaining IP Address'.
3070                  */
3071                 if (asoc->peer.transport_count == 1)
3072                         return SCTP_ERROR_DEL_LAST_IP;
3073 
3074                 /* ADDIP 4.3 D8) If a request is received to delete an IP
3075                  * address which is also the source address of the IP packet
3076                  * which contained the ASCONF chunk, the receiver MUST reject
3077                  * this request. To reject the request the receiver MUST send
3078                  * an Error Cause TLV set to the new error code 'Request to
3079                  * Delete Source IP Address'
3080                  */
3081                 if (sctp_cmp_addr_exact(&asconf->source, &addr))
3082                         return SCTP_ERROR_DEL_SRC_IP;
3083 
3084                 /* Section 4.2.2
3085                  * If the address 0.0.0.0 or ::0 is provided, all
3086                  * addresses of the peer except the source address of the
3087                  * packet MUST be deleted.
3088                  */
3089                 if (af->is_any(&addr)) {
3090                         sctp_assoc_set_primary(asoc, asconf->transport);
3091                         sctp_assoc_del_nonprimary_peers(asoc,
3092                                                         asconf->transport);
3093                 } else
3094                         sctp_assoc_del_peer(asoc, &addr);
3095                 break;
3096         case SCTP_PARAM_SET_PRIMARY:
3097                 /* ADDIP Section 4.2.4
3098                  * If the address 0.0.0.0 or ::0 is provided, the receiver
3099                  * MAY mark the source address of the packet as its
3100                  * primary.
3101                  */
3102                 if (af->is_any(&addr))
3103                         memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));
3104 
3105                 peer = sctp_assoc_lookup_paddr(asoc, &addr);
3106                 if (!peer)
3107                         return SCTP_ERROR_DNS_FAILED;
3108 
3109                 sctp_assoc_set_primary(asoc, peer);
3110                 break;
3111         }
3112 
3113         return SCTP_ERROR_NO_ERROR;
3114 }
3115 
3116 /* Verify the ASCONF packet before we process it. */
3117 bool sctp_verify_asconf(const struct sctp_association *asoc,
3118                         struct sctp_chunk *chunk, bool addr_param_needed,
3119                         struct sctp_paramhdr **errp)
3120 {
3121         sctp_addip_chunk_t *addip = (sctp_addip_chunk_t *) chunk->chunk_hdr;
3122         union sctp_params param;
3123         bool addr_param_seen = false;
3124 
3125         sctp_walk_params(param, addip, addip_hdr.params) {
3126                 size_t length = ntohs(param.p->length);
3127 
3128                 *errp = param.p;
3129                 switch (param.p->type) {
3130                 case SCTP_PARAM_ERR_CAUSE:
3131                         break;
3132                 case SCTP_PARAM_IPV4_ADDRESS:
3133                         if (length != sizeof(sctp_ipv4addr_param_t))
3134                                 return false;
3135                         addr_param_seen = true;
3136                         break;
3137                 case SCTP_PARAM_IPV6_ADDRESS:
3138                         if (length != sizeof(sctp_ipv6addr_param_t))
3139                                 return false;
3140                         addr_param_seen = true;
3141                         break;
3142                 case SCTP_PARAM_ADD_IP:
3143                 case SCTP_PARAM_DEL_IP:
3144                 case SCTP_PARAM_SET_PRIMARY:
3145                         /* In ASCONF chunks, these need to be first. */
3146                         if (addr_param_needed && !addr_param_seen)
3147                                 return false;
3148                         length = ntohs(param.addip->param_hdr.length);
3149                         if (length < sizeof(sctp_addip_param_t) +
3150                                      sizeof(sctp_paramhdr_t))
3151                                 return false;
3152                         break;
3153                 case SCTP_PARAM_SUCCESS_REPORT:
3154                 case SCTP_PARAM_ADAPTATION_LAYER_IND:
3155                         if (length != sizeof(sctp_addip_param_t))
3156                                 return false;
3157                         break;
3158                 default:
3159                         /* This is unkown to us, reject! */
3160                         return false;
3161                 }
3162         }
3163 
3164         /* Remaining sanity checks. */
3165         if (addr_param_needed && !addr_param_seen)
3166                 return false;
3167         if (!addr_param_needed && addr_param_seen)
3168                 return false;
3169         if (param.v != chunk->chunk_end)
3170                 return false;
3171 
3172         return true;
3173 }
3174 
3175 /* Process an incoming ASCONF chunk with the next expected serial no. and
3176  * return an ASCONF_ACK chunk to be sent in response.
3177  */
3178 struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
3179                                        struct sctp_chunk *asconf)
3180 {
3181         sctp_addip_chunk_t *addip = (sctp_addip_chunk_t *) asconf->chunk_hdr;
3182         bool all_param_pass = true;
3183         union sctp_params param;
3184         sctp_addiphdr_t         *hdr;
3185         union sctp_addr_param   *addr_param;
3186         sctp_addip_param_t      *asconf_param;
3187         struct sctp_chunk       *asconf_ack;
3188         __be16  err_code;
3189         int     length = 0;
3190         int     chunk_len;
3191         __u32   serial;
3192 
3193         chunk_len = ntohs(asconf->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
3194         hdr = (sctp_addiphdr_t *)asconf->skb->data;
3195         serial = ntohl(hdr->serial);
3196 
3197         /* Skip the addiphdr and store a pointer to address parameter.  */
3198         length = sizeof(sctp_addiphdr_t);
3199         addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3200         chunk_len -= length;
3201 
3202         /* Skip the address parameter and store a pointer to the first
3203          * asconf parameter.
3204          */
3205         length = ntohs(addr_param->p.length);
3206         asconf_param = (void *)addr_param + length;
3207         chunk_len -= length;
3208 
3209         /* create an ASCONF_ACK chunk.
3210          * Based on the definitions of parameters, we know that the size of
3211          * ASCONF_ACK parameters are less than or equal to the fourfold of ASCONF
3212          * parameters.
3213          */
3214         asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 4);
3215         if (!asconf_ack)
3216                 goto done;
3217 
3218         /* Process the TLVs contained within the ASCONF chunk. */
3219         sctp_walk_params(param, addip, addip_hdr.params) {
3220                 /* Skip preceeding address parameters. */
3221                 if (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
3222                     param.p->type == SCTP_PARAM_IPV6_ADDRESS)
3223                         continue;
3224 
3225                 err_code = sctp_process_asconf_param(asoc, asconf,
3226                                                      param.addip);
3227                 /* ADDIP 4.1 A7)
3228                  * If an error response is received for a TLV parameter,
3229                  * all TLVs with no response before the failed TLV are
3230                  * considered successful if not reported.  All TLVs after
3231                  * the failed response are considered unsuccessful unless
3232                  * a specific success indication is present for the parameter.
3233                  */
3234                 if (err_code != SCTP_ERROR_NO_ERROR)
3235                         all_param_pass = false;
3236                 if (!all_param_pass)
3237                         sctp_add_asconf_response(asconf_ack, param.addip->crr_id,
3238                                                  err_code, param.addip);
3239 
3240                 /* ADDIP 4.3 D11) When an endpoint receiving an ASCONF to add
3241                  * an IP address sends an 'Out of Resource' in its response, it
3242                  * MUST also fail any subsequent add or delete requests bundled
3243                  * in the ASCONF.
3244                  */
3245                 if (err_code == SCTP_ERROR_RSRC_LOW)
3246                         goto done;
3247         }
3248 done:
3249         asoc->peer.addip_serial++;
3250 
3251         /* If we are sending a new ASCONF_ACK hold a reference to it in assoc
3252          * after freeing the reference to old asconf ack if any.
3253          */
3254         if (asconf_ack) {
3255                 sctp_chunk_hold(asconf_ack);
3256                 list_add_tail(&asconf_ack->transmitted_list,
3257                               &asoc->asconf_ack_list);
3258         }
3259 
3260         return asconf_ack;
3261 }
3262 
3263 /* Process a asconf parameter that is successfully acked. */
3264 static void sctp_asconf_param_success(struct sctp_association *asoc,
3265                                      sctp_addip_param_t *asconf_param)
3266 {
3267         struct sctp_af *af;
3268         union sctp_addr addr;
3269         struct sctp_bind_addr *bp = &asoc->base.bind_addr;
3270         union sctp_addr_param *addr_param;
3271         struct sctp_transport *transport;
3272         struct sctp_sockaddr_entry *saddr;
3273 
3274         addr_param = (void *)asconf_param + sizeof(sctp_addip_param_t);
3275 
3276         /* We have checked the packet before, so we do not check again. */
3277         af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3278         af->from_addr_param(&addr, addr_param, htons(bp->port), 0);
3279 
3280         switch (asconf_param->param_hdr.type) {
3281         case SCTP_PARAM_ADD_IP:
3282                 /* This is always done in BH context with a socket lock
3283                  * held, so the list can not change.
3284                  */
3285                 local_bh_disable();
3286                 list_for_each_entry(saddr, &bp->address_list, list) {
3287                         if (sctp_cmp_addr_exact(&saddr->a, &addr))
3288                                 saddr->state = SCTP_ADDR_SRC;
3289                 }
3290                 local_bh_enable();
3291                 list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3292                                 transports) {
3293                         dst_release(transport->dst);
3294                         transport->dst = NULL;
3295                 }
3296                 break;
3297         case SCTP_PARAM_DEL_IP:
3298                 local_bh_disable();
3299                 sctp_del_bind_addr(bp, &addr);
3300                 if (asoc->asconf_addr_del_pending != NULL &&
3301                     sctp_cmp_addr_exact(asoc->asconf_addr_del_pending, &addr)) {
3302                         kfree(asoc->asconf_addr_del_pending);
3303                         asoc->asconf_addr_del_pending = NULL;
3304                 }
3305                 local_bh_enable();
3306                 list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3307                                 transports) {
3308                         dst_release(transport->dst);
3309                         transport->dst = NULL;
3310                 }
3311                 break;
3312         default:
3313                 break;
3314         }
3315 }
3316 
3317 /* Get the corresponding ASCONF response error code from the ASCONF_ACK chunk
3318  * for the given asconf parameter.  If there is no response for this parameter,
3319  * return the error code based on the third argument 'no_err'.
3320  * ADDIP 4.1
3321  * A7) If an error response is received for a TLV parameter, all TLVs with no
3322  * response before the failed TLV are considered successful if not reported.
3323  * All TLVs after the failed response are considered unsuccessful unless a
3324  * specific success indication is present for the parameter.
3325  */
3326 static __be16 sctp_get_asconf_response(struct sctp_chunk *asconf_ack,
3327                                       sctp_addip_param_t *asconf_param,
3328                                       int no_err)
3329 {
3330         sctp_addip_param_t      *asconf_ack_param;
3331         sctp_errhdr_t           *err_param;
3332         int                     length;
3333         int                     asconf_ack_len;
3334         __be16                  err_code;
3335 
3336         if (no_err)
3337                 err_code = SCTP_ERROR_NO_ERROR;
3338         else
3339                 err_code = SCTP_ERROR_REQ_REFUSED;
3340 
3341         asconf_ack_len = ntohs(asconf_ack->chunk_hdr->length) -
3342                              sizeof(sctp_chunkhdr_t);
3343 
3344         /* Skip the addiphdr from the asconf_ack chunk and store a pointer to
3345          * the first asconf_ack parameter.
3346          */
3347         length = sizeof(sctp_addiphdr_t);
3348         asconf_ack_param = (sctp_addip_param_t *)(asconf_ack->skb->data +
3349                                                   length);
3350         asconf_ack_len -= length;
3351 
3352         while (asconf_ack_len > 0) {
3353                 if (asconf_ack_param->crr_id == asconf_param->crr_id) {
3354                         switch (asconf_ack_param->param_hdr.type) {
3355                         case SCTP_PARAM_SUCCESS_REPORT:
3356                                 return SCTP_ERROR_NO_ERROR;
3357                         case SCTP_PARAM_ERR_CAUSE:
3358                                 length = sizeof(sctp_addip_param_t);
3359                                 err_param = (void *)asconf_ack_param + length;
3360                                 asconf_ack_len -= length;
3361                                 if (asconf_ack_len > 0)
3362                                         return err_param->cause;
3363                                 else
3364                                         return SCTP_ERROR_INV_PARAM;
3365                                 break;
3366                         default:
3367                                 return SCTP_ERROR_INV_PARAM;
3368                         }
3369                 }
3370 
3371                 length = ntohs(asconf_ack_param->param_hdr.length);
3372                 asconf_ack_param = (void *)asconf_ack_param + length;
3373                 asconf_ack_len -= length;
3374         }
3375 
3376         return err_code;
3377 }
3378 
3379 /* Process an incoming ASCONF_ACK chunk against the cached last ASCONF chunk. */
3380 int sctp_process_asconf_ack(struct sctp_association *asoc,
3381                             struct sctp_chunk *asconf_ack)
3382 {
3383         struct sctp_chunk       *asconf = asoc->addip_last_asconf;
3384         union sctp_addr_param   *addr_param;
3385         sctp_addip_param_t      *asconf_param;
3386         int     length = 0;
3387         int     asconf_len = asconf->skb->len;
3388         int     all_param_pass = 0;
3389         int     no_err = 1;
3390         int     retval = 0;
3391         __be16  err_code = SCTP_ERROR_NO_ERROR;
3392 
3393         /* Skip the chunkhdr and addiphdr from the last asconf sent and store
3394          * a pointer to address parameter.
3395          */
3396         length = sizeof(sctp_addip_chunk_t);
3397         addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3398         asconf_len -= length;
3399 
3400         /* Skip the address parameter in the last asconf sent and store a
3401          * pointer to the first asconf parameter.
3402          */
3403         length = ntohs(addr_param->p.length);
3404         asconf_param = (void *)addr_param + length;
3405         asconf_len -= length;
3406 
3407         /* ADDIP 4.1
3408          * A8) If there is no response(s) to specific TLV parameter(s), and no
3409          * failures are indicated, then all request(s) are considered
3410          * successful.
3411          */
3412         if (asconf_ack->skb->len == sizeof(sctp_addiphdr_t))
3413                 all_param_pass = 1;
3414 
3415         /* Process the TLVs contained in the last sent ASCONF chunk. */
3416         while (asconf_len > 0) {
3417                 if (all_param_pass)
3418                         err_code = SCTP_ERROR_NO_ERROR;
3419                 else {
3420                         err_code = sctp_get_asconf_response(asconf_ack,
3421                                                             asconf_param,
3422                                                             no_err);
3423                         if (no_err && (SCTP_ERROR_NO_ERROR != err_code))
3424                                 no_err = 0;
3425                 }
3426 
3427                 switch (err_code) {
3428                 case SCTP_ERROR_NO_ERROR:
3429                         sctp_asconf_param_success(asoc, asconf_param);
3430                         break;
3431 
3432                 case SCTP_ERROR_RSRC_LOW:
3433                         retval = 1;
3434                         break;
3435 
3436                 case SCTP_ERROR_UNKNOWN_PARAM:
3437                         /* Disable sending this type of asconf parameter in
3438                          * future.
3439                          */
3440                         asoc->peer.addip_disabled_mask |=
3441                                 asconf_param->param_hdr.type;
3442                         break;
3443 
3444                 case SCTP_ERROR_REQ_REFUSED:
3445                 case SCTP_ERROR_DEL_LAST_IP:
3446                 case SCTP_ERROR_DEL_SRC_IP:
3447                 default:
3448                          break;
3449                 }
3450 
3451                 /* Skip the processed asconf parameter and move to the next
3452                  * one.
3453                  */
3454                 length = ntohs(asconf_param->param_hdr.length);
3455                 asconf_param = (void *)asconf_param + length;
3456                 asconf_len -= length;
3457         }
3458 
3459         if (no_err && asoc->src_out_of_asoc_ok) {
3460                 asoc->src_out_of_asoc_ok = 0;
3461                 sctp_transport_immediate_rtx(asoc->peer.primary_path);
3462         }
3463 
3464         /* Free the cached last sent asconf chunk. */
3465         list_del_init(&asconf->transmitted_list);
3466         sctp_chunk_free(asconf);
3467         asoc->addip_last_asconf = NULL;
3468 
3469         return retval;
3470 }
3471 
3472 /* Make a FWD TSN chunk. */
3473 struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
3474                                     __u32 new_cum_tsn, size_t nstreams,
3475                                     struct sctp_fwdtsn_skip *skiplist)
3476 {
3477         struct sctp_chunk *retval = NULL;
3478         struct sctp_fwdtsn_hdr ftsn_hdr;
3479         struct sctp_fwdtsn_skip skip;
3480         size_t hint;
3481         int i;
3482 
3483         hint = (nstreams + 1) * sizeof(__u32);
3484 
3485         retval = sctp_make_control(asoc, SCTP_CID_FWD_TSN, 0, hint);
3486 
3487         if (!retval)
3488                 return NULL;
3489 
3490         ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
3491         retval->subh.fwdtsn_hdr =
3492                 sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
3493 
3494         for (i = 0; i < nstreams; i++) {
3495                 skip.stream = skiplist[i].stream;
3496                 skip.ssn = skiplist[i].ssn;
3497                 sctp_addto_chunk(retval, sizeof(skip), &skip);
3498         }
3499 
3500         return retval;
3501 }
3502 

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