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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 <crypto/hash.h>
 49 #include <linux/types.h>
 50 #include <linux/kernel.h>
 51 #include <linux/ip.h>
 52 #include <linux/ipv6.h>
 53 #include <linux/net.h>
 54 #include <linux/inet.h>
 55 #include <linux/scatterlist.h>
 56 #include <linux/slab.h>
 57 #include <net/sock.h>
 58 
 59 #include <linux/skbuff.h>
 60 #include <linux/random.h>       /* for get_random_bytes */
 61 #include <net/sctp/sctp.h>
 62 #include <net/sctp/sm.h>
 63 
 64 static struct sctp_chunk *sctp_make_control(const struct sctp_association *asoc,
 65                                             __u8 type, __u8 flags, int paylen,
 66                                             gfp_t gfp);
 67 static struct sctp_chunk *sctp_make_data(const struct sctp_association *asoc,
 68                                          __u8 flags, int paylen, gfp_t gfp);
 69 static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc,
 70                                            __u8 type, __u8 flags, int paylen,
 71                                            gfp_t gfp);
 72 static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
 73                                         const struct sctp_association *asoc,
 74                                         const struct sctp_chunk *init_chunk,
 75                                         int *cookie_len,
 76                                         const __u8 *raw_addrs, int addrs_len);
 77 static int sctp_process_param(struct sctp_association *asoc,
 78                               union sctp_params param,
 79                               const union sctp_addr *peer_addr,
 80                               gfp_t gfp);
 81 static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
 82                               const void *data);
 83 static void  *sctp_addto_chunk_fixed(struct sctp_chunk *, int len,
 84                                      const void *data);
 85 
 86 /* Control chunk destructor */
 87 static void sctp_control_release_owner(struct sk_buff *skb)
 88 {
 89         /*TODO: do memory release */
 90 }
 91 
 92 static void sctp_control_set_owner_w(struct sctp_chunk *chunk)
 93 {
 94         struct sctp_association *asoc = chunk->asoc;
 95         struct sk_buff *skb = chunk->skb;
 96 
 97         /* TODO: properly account for control chunks.
 98          * To do it right we'll need:
 99          *  1) endpoint if association isn't known.
100          *  2) proper memory accounting.
101          *
102          *  For now don't do anything for now.
103          */
104         skb->sk = asoc ? asoc->base.sk : NULL;
105         skb->destructor = sctp_control_release_owner;
106 }
107 
108 /* What was the inbound interface for this chunk? */
109 int sctp_chunk_iif(const struct sctp_chunk *chunk)
110 {
111         struct sk_buff *skb = chunk->skb;
112 
113         return SCTP_INPUT_CB(skb)->af->skb_iif(skb);
114 }
115 
116 /* RFC 2960 3.3.2 Initiation (INIT) (1)
117  *
118  * Note 2: The ECN capable field is reserved for future use of
119  * Explicit Congestion Notification.
120  */
121 static const struct sctp_paramhdr ecap_param = {
122         SCTP_PARAM_ECN_CAPABLE,
123         cpu_to_be16(sizeof(struct sctp_paramhdr)),
124 };
125 static const struct sctp_paramhdr prsctp_param = {
126         SCTP_PARAM_FWD_TSN_SUPPORT,
127         cpu_to_be16(sizeof(struct sctp_paramhdr)),
128 };
129 
130 /* A helper to initialize an op error inside a
131  * provided chunk, as most cause codes will be embedded inside an
132  * abort chunk.
133  */
134 void  sctp_init_cause(struct sctp_chunk *chunk, __be16 cause_code,
135                       size_t paylen)
136 {
137         sctp_errhdr_t err;
138         __u16 len;
139 
140         /* Cause code constants are now defined in network order.  */
141         err.cause = cause_code;
142         len = sizeof(sctp_errhdr_t) + paylen;
143         err.length  = htons(len);
144         chunk->subh.err_hdr = sctp_addto_chunk(chunk, sizeof(sctp_errhdr_t), &err);
145 }
146 
147 /* A helper to initialize an op error inside a
148  * provided chunk, as most cause codes will be embedded inside an
149  * abort chunk.  Differs from sctp_init_cause in that it won't oops
150  * if there isn't enough space in the op error chunk
151  */
152 static int sctp_init_cause_fixed(struct sctp_chunk *chunk, __be16 cause_code,
153                       size_t paylen)
154 {
155         sctp_errhdr_t err;
156         __u16 len;
157 
158         /* Cause code constants are now defined in network order.  */
159         err.cause = cause_code;
160         len = sizeof(sctp_errhdr_t) + paylen;
161         err.length  = htons(len);
162 
163         if (skb_tailroom(chunk->skb) < len)
164                 return -ENOSPC;
165         chunk->subh.err_hdr = sctp_addto_chunk_fixed(chunk,
166                                                      sizeof(sctp_errhdr_t),
167                                                      &err);
168         return 0;
169 }
170 /* 3.3.2 Initiation (INIT) (1)
171  *
172  * This chunk is used to initiate a SCTP association between two
173  * endpoints. The format of the INIT chunk is shown below:
174  *
175  *     0                   1                   2                   3
176  *     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
177  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
178  *    |   Type = 1    |  Chunk Flags  |      Chunk Length             |
179  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
180  *    |                         Initiate Tag                          |
181  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
182  *    |           Advertised Receiver Window Credit (a_rwnd)          |
183  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
184  *    |  Number of Outbound Streams   |  Number of Inbound Streams    |
185  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
186  *    |                          Initial TSN                          |
187  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
188  *    \                                                               \
189  *    /              Optional/Variable-Length Parameters              /
190  *    \                                                               \
191  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
192  *
193  *
194  * The INIT chunk contains the following parameters. Unless otherwise
195  * noted, each parameter MUST only be included once in the INIT chunk.
196  *
197  * Fixed Parameters                     Status
198  * ----------------------------------------------
199  * Initiate Tag                        Mandatory
200  * Advertised Receiver Window Credit   Mandatory
201  * Number of Outbound Streams          Mandatory
202  * Number of Inbound Streams           Mandatory
203  * Initial TSN                         Mandatory
204  *
205  * Variable Parameters                  Status     Type Value
206  * -------------------------------------------------------------
207  * IPv4 Address (Note 1)               Optional    5
208  * IPv6 Address (Note 1)               Optional    6
209  * Cookie Preservative                 Optional    9
210  * Reserved for ECN Capable (Note 2)   Optional    32768 (0x8000)
211  * Host Name Address (Note 3)          Optional    11
212  * Supported Address Types (Note 4)    Optional    12
213  */
214 struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc,
215                              const struct sctp_bind_addr *bp,
216                              gfp_t gfp, int vparam_len)
217 {
218         struct net *net = sock_net(asoc->base.sk);
219         struct sctp_endpoint *ep = asoc->ep;
220         struct sctp_inithdr init;
221         union sctp_params addrs;
222         size_t chunksize;
223         struct sctp_chunk *retval = NULL;
224         int num_types, addrs_len = 0;
225         struct sctp_sock *sp;
226         sctp_supported_addrs_param_t sat;
227         __be16 types[2];
228         sctp_adaptation_ind_param_t aiparam;
229         sctp_supported_ext_param_t ext_param;
230         int num_ext = 0;
231         __u8 extensions[4];
232         struct sctp_paramhdr *auth_chunks = NULL,
233                         *auth_hmacs = NULL;
234 
235         /* RFC 2960 3.3.2 Initiation (INIT) (1)
236          *
237          * Note 1: The INIT chunks can contain multiple addresses that
238          * can be IPv4 and/or IPv6 in any combination.
239          */
240         retval = NULL;
241 
242         /* Convert the provided bind address list to raw format. */
243         addrs = sctp_bind_addrs_to_raw(bp, &addrs_len, gfp);
244 
245         init.init_tag              = htonl(asoc->c.my_vtag);
246         init.a_rwnd                = htonl(asoc->rwnd);
247         init.num_outbound_streams  = htons(asoc->c.sinit_num_ostreams);
248         init.num_inbound_streams   = htons(asoc->c.sinit_max_instreams);
249         init.initial_tsn           = htonl(asoc->c.initial_tsn);
250 
251         /* How many address types are needed? */
252         sp = sctp_sk(asoc->base.sk);
253         num_types = sp->pf->supported_addrs(sp, types);
254 
255         chunksize = sizeof(init) + addrs_len;
256         chunksize += SCTP_PAD4(SCTP_SAT_LEN(num_types));
257         chunksize += sizeof(ecap_param);
258 
259         if (asoc->prsctp_enable)
260                 chunksize += sizeof(prsctp_param);
261 
262         /* ADDIP: Section 4.2.7:
263          *  An implementation supporting this extension [ADDIP] MUST list
264          *  the ASCONF,the ASCONF-ACK, and the AUTH  chunks in its INIT and
265          *  INIT-ACK parameters.
266          */
267         if (net->sctp.addip_enable) {
268                 extensions[num_ext] = SCTP_CID_ASCONF;
269                 extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
270                 num_ext += 2;
271         }
272 
273         if (asoc->reconf_enable) {
274                 extensions[num_ext] = SCTP_CID_RECONF;
275                 num_ext += 1;
276         }
277 
278         if (sp->adaptation_ind)
279                 chunksize += sizeof(aiparam);
280 
281         chunksize += vparam_len;
282 
283         /* Account for AUTH related parameters */
284         if (ep->auth_enable) {
285                 /* Add random parameter length*/
286                 chunksize += sizeof(asoc->c.auth_random);
287 
288                 /* Add HMACS parameter length if any were defined */
289                 auth_hmacs = (struct sctp_paramhdr *)asoc->c.auth_hmacs;
290                 if (auth_hmacs->length)
291                         chunksize += SCTP_PAD4(ntohs(auth_hmacs->length));
292                 else
293                         auth_hmacs = NULL;
294 
295                 /* Add CHUNKS parameter length */
296                 auth_chunks = (struct sctp_paramhdr *)asoc->c.auth_chunks;
297                 if (auth_chunks->length)
298                         chunksize += SCTP_PAD4(ntohs(auth_chunks->length));
299                 else
300                         auth_chunks = NULL;
301 
302                 extensions[num_ext] = SCTP_CID_AUTH;
303                 num_ext += 1;
304         }
305 
306         /* If we have any extensions to report, account for that */
307         if (num_ext)
308                 chunksize += SCTP_PAD4(sizeof(sctp_supported_ext_param_t) +
309                                        num_ext);
310 
311         /* RFC 2960 3.3.2 Initiation (INIT) (1)
312          *
313          * Note 3: An INIT chunk MUST NOT contain more than one Host
314          * Name address parameter. Moreover, the sender of the INIT
315          * MUST NOT combine any other address types with the Host Name
316          * address in the INIT. The receiver of INIT MUST ignore any
317          * other address types if the Host Name address parameter is
318          * present in the received INIT chunk.
319          *
320          * PLEASE DO NOT FIXME [This version does not support Host Name.]
321          */
322 
323         retval = sctp_make_control(asoc, SCTP_CID_INIT, 0, chunksize, gfp);
324         if (!retval)
325                 goto nodata;
326 
327         retval->subh.init_hdr =
328                 sctp_addto_chunk(retval, sizeof(init), &init);
329         retval->param_hdr.v =
330                 sctp_addto_chunk(retval, addrs_len, addrs.v);
331 
332         /* RFC 2960 3.3.2 Initiation (INIT) (1)
333          *
334          * Note 4: This parameter, when present, specifies all the
335          * address types the sending endpoint can support. The absence
336          * of this parameter indicates that the sending endpoint can
337          * support any address type.
338          */
339         sat.param_hdr.type = SCTP_PARAM_SUPPORTED_ADDRESS_TYPES;
340         sat.param_hdr.length = htons(SCTP_SAT_LEN(num_types));
341         sctp_addto_chunk(retval, sizeof(sat), &sat);
342         sctp_addto_chunk(retval, num_types * sizeof(__u16), &types);
343 
344         sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
345 
346         /* Add the supported extensions parameter.  Be nice and add this
347          * fist before addiding the parameters for the extensions themselves
348          */
349         if (num_ext) {
350                 ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
351                 ext_param.param_hdr.length =
352                             htons(sizeof(sctp_supported_ext_param_t) + num_ext);
353                 sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
354                                 &ext_param);
355                 sctp_addto_param(retval, num_ext, extensions);
356         }
357 
358         if (asoc->prsctp_enable)
359                 sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
360 
361         if (sp->adaptation_ind) {
362                 aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
363                 aiparam.param_hdr.length = htons(sizeof(aiparam));
364                 aiparam.adaptation_ind = htonl(sp->adaptation_ind);
365                 sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
366         }
367 
368         /* Add SCTP-AUTH chunks to the parameter list */
369         if (ep->auth_enable) {
370                 sctp_addto_chunk(retval, sizeof(asoc->c.auth_random),
371                                  asoc->c.auth_random);
372                 if (auth_hmacs)
373                         sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
374                                         auth_hmacs);
375                 if (auth_chunks)
376                         sctp_addto_chunk(retval, ntohs(auth_chunks->length),
377                                         auth_chunks);
378         }
379 nodata:
380         kfree(addrs.v);
381         return retval;
382 }
383 
384 struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc,
385                                  const struct sctp_chunk *chunk,
386                                  gfp_t gfp, int unkparam_len)
387 {
388         struct sctp_inithdr initack;
389         struct sctp_chunk *retval;
390         union sctp_params addrs;
391         struct sctp_sock *sp;
392         int addrs_len;
393         sctp_cookie_param_t *cookie;
394         int cookie_len;
395         size_t chunksize;
396         sctp_adaptation_ind_param_t aiparam;
397         sctp_supported_ext_param_t ext_param;
398         int num_ext = 0;
399         __u8 extensions[4];
400         struct sctp_paramhdr *auth_chunks = NULL,
401                         *auth_hmacs = NULL,
402                         *auth_random = NULL;
403 
404         retval = NULL;
405 
406         /* Note: there may be no addresses to embed. */
407         addrs = sctp_bind_addrs_to_raw(&asoc->base.bind_addr, &addrs_len, gfp);
408 
409         initack.init_tag                = htonl(asoc->c.my_vtag);
410         initack.a_rwnd                  = htonl(asoc->rwnd);
411         initack.num_outbound_streams    = htons(asoc->c.sinit_num_ostreams);
412         initack.num_inbound_streams     = htons(asoc->c.sinit_max_instreams);
413         initack.initial_tsn             = htonl(asoc->c.initial_tsn);
414 
415         /* FIXME:  We really ought to build the cookie right
416          * into the packet instead of allocating more fresh memory.
417          */
418         cookie = sctp_pack_cookie(asoc->ep, asoc, chunk, &cookie_len,
419                                   addrs.v, addrs_len);
420         if (!cookie)
421                 goto nomem_cookie;
422 
423         /* Calculate the total size of allocation, include the reserved
424          * space for reporting unknown parameters if it is specified.
425          */
426         sp = sctp_sk(asoc->base.sk);
427         chunksize = sizeof(initack) + addrs_len + cookie_len + unkparam_len;
428 
429         /* Tell peer that we'll do ECN only if peer advertised such cap.  */
430         if (asoc->peer.ecn_capable)
431                 chunksize += sizeof(ecap_param);
432 
433         if (asoc->peer.prsctp_capable)
434                 chunksize += sizeof(prsctp_param);
435 
436         if (asoc->peer.asconf_capable) {
437                 extensions[num_ext] = SCTP_CID_ASCONF;
438                 extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
439                 num_ext += 2;
440         }
441 
442         if (asoc->peer.reconf_capable) {
443                 extensions[num_ext] = SCTP_CID_RECONF;
444                 num_ext += 1;
445         }
446 
447         if (sp->adaptation_ind)
448                 chunksize += sizeof(aiparam);
449 
450         if (asoc->peer.auth_capable) {
451                 auth_random = (struct sctp_paramhdr *)asoc->c.auth_random;
452                 chunksize += ntohs(auth_random->length);
453 
454                 auth_hmacs = (struct sctp_paramhdr *)asoc->c.auth_hmacs;
455                 if (auth_hmacs->length)
456                         chunksize += SCTP_PAD4(ntohs(auth_hmacs->length));
457                 else
458                         auth_hmacs = NULL;
459 
460                 auth_chunks = (struct sctp_paramhdr *)asoc->c.auth_chunks;
461                 if (auth_chunks->length)
462                         chunksize += SCTP_PAD4(ntohs(auth_chunks->length));
463                 else
464                         auth_chunks = NULL;
465 
466                 extensions[num_ext] = SCTP_CID_AUTH;
467                 num_ext += 1;
468         }
469 
470         if (num_ext)
471                 chunksize += SCTP_PAD4(sizeof(sctp_supported_ext_param_t) +
472                                        num_ext);
473 
474         /* Now allocate and fill out the chunk.  */
475         retval = sctp_make_control(asoc, SCTP_CID_INIT_ACK, 0, chunksize, gfp);
476         if (!retval)
477                 goto nomem_chunk;
478 
479         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
480          *
481          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
482          * HEARTBEAT ACK, * etc.) to the same destination transport
483          * address from which it received the DATA or control chunk
484          * to which it is replying.
485          *
486          * [INIT ACK back to where the INIT came from.]
487          */
488         retval->transport = chunk->transport;
489 
490         retval->subh.init_hdr =
491                 sctp_addto_chunk(retval, sizeof(initack), &initack);
492         retval->param_hdr.v = sctp_addto_chunk(retval, addrs_len, addrs.v);
493         sctp_addto_chunk(retval, cookie_len, cookie);
494         if (asoc->peer.ecn_capable)
495                 sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
496         if (num_ext) {
497                 ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
498                 ext_param.param_hdr.length =
499                             htons(sizeof(sctp_supported_ext_param_t) + num_ext);
500                 sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
501                                  &ext_param);
502                 sctp_addto_param(retval, num_ext, extensions);
503         }
504         if (asoc->peer.prsctp_capable)
505                 sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
506 
507         if (sp->adaptation_ind) {
508                 aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
509                 aiparam.param_hdr.length = htons(sizeof(aiparam));
510                 aiparam.adaptation_ind = htonl(sp->adaptation_ind);
511                 sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
512         }
513 
514         if (asoc->peer.auth_capable) {
515                 sctp_addto_chunk(retval, ntohs(auth_random->length),
516                                  auth_random);
517                 if (auth_hmacs)
518                         sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
519                                         auth_hmacs);
520                 if (auth_chunks)
521                         sctp_addto_chunk(retval, ntohs(auth_chunks->length),
522                                         auth_chunks);
523         }
524 
525         /* We need to remove the const qualifier at this point.  */
526         retval->asoc = (struct sctp_association *) asoc;
527 
528 nomem_chunk:
529         kfree(cookie);
530 nomem_cookie:
531         kfree(addrs.v);
532         return retval;
533 }
534 
535 /* 3.3.11 Cookie Echo (COOKIE ECHO) (10):
536  *
537  * This chunk is used only during the initialization of an association.
538  * It is sent by the initiator of an association to its peer to complete
539  * the initialization process. This chunk MUST precede any DATA chunk
540  * sent within the association, but MAY be bundled with one or more DATA
541  * chunks in the same packet.
542  *
543  *      0                   1                   2                   3
544  *      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
545  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
546  *     |   Type = 10   |Chunk  Flags   |         Length                |
547  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
548  *     /                     Cookie                                    /
549  *     \                                                               \
550  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
551  *
552  * Chunk Flags: 8 bit
553  *
554  *   Set to zero on transmit and ignored on receipt.
555  *
556  * Length: 16 bits (unsigned integer)
557  *
558  *   Set to the size of the chunk in bytes, including the 4 bytes of
559  *   the chunk header and the size of the Cookie.
560  *
561  * Cookie: variable size
562  *
563  *   This field must contain the exact cookie received in the
564  *   State Cookie parameter from the previous INIT ACK.
565  *
566  *   An implementation SHOULD make the cookie as small as possible
567  *   to insure interoperability.
568  */
569 struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *asoc,
570                                     const struct sctp_chunk *chunk)
571 {
572         struct sctp_chunk *retval;
573         void *cookie;
574         int cookie_len;
575 
576         cookie = asoc->peer.cookie;
577         cookie_len = asoc->peer.cookie_len;
578 
579         /* Build a cookie echo chunk.  */
580         retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ECHO, 0,
581                                    cookie_len, GFP_ATOMIC);
582         if (!retval)
583                 goto nodata;
584         retval->subh.cookie_hdr =
585                 sctp_addto_chunk(retval, cookie_len, cookie);
586 
587         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
588          *
589          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
590          * HEARTBEAT ACK, * etc.) to the same destination transport
591          * address from which it * received the DATA or control chunk
592          * to which it is replying.
593          *
594          * [COOKIE ECHO back to where the INIT ACK came from.]
595          */
596         if (chunk)
597                 retval->transport = chunk->transport;
598 
599 nodata:
600         return retval;
601 }
602 
603 /* 3.3.12 Cookie Acknowledgement (COOKIE ACK) (11):
604  *
605  * This chunk is used only during the initialization of an
606  * association.  It is used to acknowledge the receipt of a COOKIE
607  * ECHO chunk.  This chunk MUST precede any DATA or SACK chunk sent
608  * within the association, but MAY be bundled with one or more DATA
609  * chunks or SACK chunk in the same SCTP packet.
610  *
611  *      0                   1                   2                   3
612  *      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
613  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
614  *     |   Type = 11   |Chunk  Flags   |     Length = 4                |
615  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
616  *
617  * Chunk Flags: 8 bits
618  *
619  *   Set to zero on transmit and ignored on receipt.
620  */
621 struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *asoc,
622                                    const struct sctp_chunk *chunk)
623 {
624         struct sctp_chunk *retval;
625 
626         retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ACK, 0, 0, GFP_ATOMIC);
627 
628         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
629          *
630          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
631          * HEARTBEAT ACK, * etc.) to the same destination transport
632          * address from which it * received the DATA or control chunk
633          * to which it is replying.
634          *
635          * [COOKIE ACK back to where the COOKIE ECHO came from.]
636          */
637         if (retval && chunk)
638                 retval->transport = chunk->transport;
639 
640         return retval;
641 }
642 
643 /*
644  *  Appendix A: Explicit Congestion Notification:
645  *  CWR:
646  *
647  *  RFC 2481 details a specific bit for a sender to send in the header of
648  *  its next outbound TCP segment to indicate to its peer that it has
649  *  reduced its congestion window.  This is termed the CWR bit.  For
650  *  SCTP the same indication is made by including the CWR chunk.
651  *  This chunk contains one data element, i.e. the TSN number that
652  *  was sent in the ECNE chunk.  This element represents the lowest
653  *  TSN number in the datagram that was originally marked with the
654  *  CE bit.
655  *
656  *     0                   1                   2                   3
657  *     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
658  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
659  *    | Chunk Type=13 | Flags=00000000|    Chunk Length = 8           |
660  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
661  *    |                      Lowest TSN Number                        |
662  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
663  *
664  *     Note: The CWR is considered a Control chunk.
665  */
666 struct sctp_chunk *sctp_make_cwr(const struct sctp_association *asoc,
667                             const __u32 lowest_tsn,
668                             const struct sctp_chunk *chunk)
669 {
670         struct sctp_chunk *retval;
671         sctp_cwrhdr_t cwr;
672 
673         cwr.lowest_tsn = htonl(lowest_tsn);
674         retval = sctp_make_control(asoc, SCTP_CID_ECN_CWR, 0,
675                                    sizeof(sctp_cwrhdr_t), GFP_ATOMIC);
676 
677         if (!retval)
678                 goto nodata;
679 
680         retval->subh.ecn_cwr_hdr =
681                 sctp_addto_chunk(retval, sizeof(cwr), &cwr);
682 
683         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
684          *
685          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
686          * HEARTBEAT ACK, * etc.) to the same destination transport
687          * address from which it * received the DATA or control chunk
688          * to which it is replying.
689          *
690          * [Report a reduced congestion window back to where the ECNE
691          * came from.]
692          */
693         if (chunk)
694                 retval->transport = chunk->transport;
695 
696 nodata:
697         return retval;
698 }
699 
700 /* Make an ECNE chunk.  This is a congestion experienced report.  */
701 struct sctp_chunk *sctp_make_ecne(const struct sctp_association *asoc,
702                              const __u32 lowest_tsn)
703 {
704         struct sctp_chunk *retval;
705         sctp_ecnehdr_t ecne;
706 
707         ecne.lowest_tsn = htonl(lowest_tsn);
708         retval = sctp_make_control(asoc, SCTP_CID_ECN_ECNE, 0,
709                                    sizeof(sctp_ecnehdr_t), GFP_ATOMIC);
710         if (!retval)
711                 goto nodata;
712         retval->subh.ecne_hdr =
713                 sctp_addto_chunk(retval, sizeof(ecne), &ecne);
714 
715 nodata:
716         return retval;
717 }
718 
719 /* Make a DATA chunk for the given association from the provided
720  * parameters.  However, do not populate the data payload.
721  */
722 struct sctp_chunk *sctp_make_datafrag_empty(struct sctp_association *asoc,
723                                        const struct sctp_sndrcvinfo *sinfo,
724                                        int data_len, __u8 flags, __u16 ssn,
725                                        gfp_t gfp)
726 {
727         struct sctp_chunk *retval;
728         struct sctp_datahdr dp;
729         int chunk_len;
730 
731         /* We assign the TSN as LATE as possible, not here when
732          * creating the chunk.
733          */
734         dp.tsn = 0;
735         dp.stream = htons(sinfo->sinfo_stream);
736         dp.ppid   = sinfo->sinfo_ppid;
737 
738         /* Set the flags for an unordered send.  */
739         if (sinfo->sinfo_flags & SCTP_UNORDERED) {
740                 flags |= SCTP_DATA_UNORDERED;
741                 dp.ssn = 0;
742         } else
743                 dp.ssn = htons(ssn);
744 
745         chunk_len = sizeof(dp) + data_len;
746         retval = sctp_make_data(asoc, flags, chunk_len, gfp);
747         if (!retval)
748                 goto nodata;
749 
750         retval->subh.data_hdr = sctp_addto_chunk(retval, sizeof(dp), &dp);
751         memcpy(&retval->sinfo, sinfo, sizeof(struct sctp_sndrcvinfo));
752 
753 nodata:
754         return retval;
755 }
756 
757 /* Create a selective ackowledgement (SACK) for the given
758  * association.  This reports on which TSN's we've seen to date,
759  * including duplicates and gaps.
760  */
761 struct sctp_chunk *sctp_make_sack(const struct sctp_association *asoc)
762 {
763         struct sctp_chunk *retval;
764         struct sctp_sackhdr sack;
765         int len;
766         __u32 ctsn;
767         __u16 num_gabs, num_dup_tsns;
768         struct sctp_association *aptr = (struct sctp_association *)asoc;
769         struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
770         struct sctp_gap_ack_block gabs[SCTP_MAX_GABS];
771         struct sctp_transport *trans;
772 
773         memset(gabs, 0, sizeof(gabs));
774         ctsn = sctp_tsnmap_get_ctsn(map);
775 
776         pr_debug("%s: sackCTSNAck sent:0x%x\n", __func__, ctsn);
777 
778         /* How much room is needed in the chunk? */
779         num_gabs = sctp_tsnmap_num_gabs(map, gabs);
780         num_dup_tsns = sctp_tsnmap_num_dups(map);
781 
782         /* Initialize the SACK header.  */
783         sack.cum_tsn_ack            = htonl(ctsn);
784         sack.a_rwnd                 = htonl(asoc->a_rwnd);
785         sack.num_gap_ack_blocks     = htons(num_gabs);
786         sack.num_dup_tsns           = htons(num_dup_tsns);
787 
788         len = sizeof(sack)
789                 + sizeof(struct sctp_gap_ack_block) * num_gabs
790                 + sizeof(__u32) * num_dup_tsns;
791 
792         /* Create the chunk.  */
793         retval = sctp_make_control(asoc, SCTP_CID_SACK, 0, len, GFP_ATOMIC);
794         if (!retval)
795                 goto nodata;
796 
797         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
798          *
799          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
800          * HEARTBEAT ACK, etc.) to the same destination transport
801          * address from which it received the DATA or control chunk to
802          * which it is replying.  This rule should also be followed if
803          * the endpoint is bundling DATA chunks together with the
804          * reply chunk.
805          *
806          * However, when acknowledging multiple DATA chunks received
807          * in packets from different source addresses in a single
808          * SACK, the SACK chunk may be transmitted to one of the
809          * destination transport addresses from which the DATA or
810          * control chunks being acknowledged were received.
811          *
812          * [BUG:  We do not implement the following paragraph.
813          * Perhaps we should remember the last transport we used for a
814          * SACK and avoid that (if possible) if we have seen any
815          * duplicates. --piggy]
816          *
817          * When a receiver of a duplicate DATA chunk sends a SACK to a
818          * multi- homed endpoint it MAY be beneficial to vary the
819          * destination address and not use the source address of the
820          * DATA chunk.  The reason being that receiving a duplicate
821          * from a multi-homed endpoint might indicate that the return
822          * path (as specified in the source address of the DATA chunk)
823          * for the SACK is broken.
824          *
825          * [Send to the address from which we last received a DATA chunk.]
826          */
827         retval->transport = asoc->peer.last_data_from;
828 
829         retval->subh.sack_hdr =
830                 sctp_addto_chunk(retval, sizeof(sack), &sack);
831 
832         /* Add the gap ack block information.   */
833         if (num_gabs)
834                 sctp_addto_chunk(retval, sizeof(__u32) * num_gabs,
835                                  gabs);
836 
837         /* Add the duplicate TSN information.  */
838         if (num_dup_tsns) {
839                 aptr->stats.idupchunks += num_dup_tsns;
840                 sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns,
841                                  sctp_tsnmap_get_dups(map));
842         }
843         /* Once we have a sack generated, check to see what our sack
844          * generation is, if its 0, reset the transports to 0, and reset
845          * the association generation to 1
846          *
847          * The idea is that zero is never used as a valid generation for the
848          * association so no transport will match after a wrap event like this,
849          * Until the next sack
850          */
851         if (++aptr->peer.sack_generation == 0) {
852                 list_for_each_entry(trans, &asoc->peer.transport_addr_list,
853                                     transports)
854                         trans->sack_generation = 0;
855                 aptr->peer.sack_generation = 1;
856         }
857 nodata:
858         return retval;
859 }
860 
861 /* Make a SHUTDOWN chunk. */
862 struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
863                                       const struct sctp_chunk *chunk)
864 {
865         struct sctp_chunk *retval;
866         sctp_shutdownhdr_t shut;
867         __u32 ctsn;
868 
869         ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
870         shut.cum_tsn_ack = htonl(ctsn);
871 
872         retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN, 0,
873                                    sizeof(sctp_shutdownhdr_t), GFP_ATOMIC);
874         if (!retval)
875                 goto nodata;
876 
877         retval->subh.shutdown_hdr =
878                 sctp_addto_chunk(retval, sizeof(shut), &shut);
879 
880         if (chunk)
881                 retval->transport = chunk->transport;
882 nodata:
883         return retval;
884 }
885 
886 struct sctp_chunk *sctp_make_shutdown_ack(const struct sctp_association *asoc,
887                                      const struct sctp_chunk *chunk)
888 {
889         struct sctp_chunk *retval;
890 
891         retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_ACK, 0, 0,
892                                    GFP_ATOMIC);
893 
894         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
895          *
896          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
897          * HEARTBEAT ACK, * etc.) to the same destination transport
898          * address from which it * received the DATA or control chunk
899          * to which it is replying.
900          *
901          * [ACK back to where the SHUTDOWN came from.]
902          */
903         if (retval && chunk)
904                 retval->transport = chunk->transport;
905 
906         return retval;
907 }
908 
909 struct sctp_chunk *sctp_make_shutdown_complete(
910         const struct sctp_association *asoc,
911         const struct sctp_chunk *chunk)
912 {
913         struct sctp_chunk *retval;
914         __u8 flags = 0;
915 
916         /* Set the T-bit if we have no association (vtag will be
917          * reflected)
918          */
919         flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;
920 
921         retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags,
922                                    0, GFP_ATOMIC);
923 
924         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
925          *
926          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
927          * HEARTBEAT ACK, * etc.) to the same destination transport
928          * address from which it * received the DATA or control chunk
929          * to which it is replying.
930          *
931          * [Report SHUTDOWN COMPLETE back to where the SHUTDOWN ACK
932          * came from.]
933          */
934         if (retval && chunk)
935                 retval->transport = chunk->transport;
936 
937         return retval;
938 }
939 
940 /* Create an ABORT.  Note that we set the T bit if we have no
941  * association, except when responding to an INIT (sctpimpguide 2.41).
942  */
943 struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc,
944                               const struct sctp_chunk *chunk,
945                               const size_t hint)
946 {
947         struct sctp_chunk *retval;
948         __u8 flags = 0;
949 
950         /* Set the T-bit if we have no association and 'chunk' is not
951          * an INIT (vtag will be reflected).
952          */
953         if (!asoc) {
954                 if (chunk && chunk->chunk_hdr &&
955                     chunk->chunk_hdr->type == SCTP_CID_INIT)
956                         flags = 0;
957                 else
958                         flags = SCTP_CHUNK_FLAG_T;
959         }
960 
961         retval = sctp_make_control(asoc, SCTP_CID_ABORT, flags, hint,
962                                    GFP_ATOMIC);
963 
964         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
965          *
966          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
967          * HEARTBEAT ACK, * etc.) to the same destination transport
968          * address from which it * received the DATA or control chunk
969          * to which it is replying.
970          *
971          * [ABORT back to where the offender came from.]
972          */
973         if (retval && chunk)
974                 retval->transport = chunk->transport;
975 
976         return retval;
977 }
978 
979 /* Helper to create ABORT with a NO_USER_DATA error.  */
980 struct sctp_chunk *sctp_make_abort_no_data(
981         const struct sctp_association *asoc,
982         const struct sctp_chunk *chunk, __u32 tsn)
983 {
984         struct sctp_chunk *retval;
985         __be32 payload;
986 
987         retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t)
988                                  + sizeof(tsn));
989 
990         if (!retval)
991                 goto no_mem;
992 
993         /* Put the tsn back into network byte order.  */
994         payload = htonl(tsn);
995         sctp_init_cause(retval, SCTP_ERROR_NO_DATA, sizeof(payload));
996         sctp_addto_chunk(retval, sizeof(payload), (const void *)&payload);
997 
998         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
999          *
1000          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1001          * HEARTBEAT ACK, * etc.) to the same destination transport
1002          * address from which it * received the DATA or control chunk
1003          * to which it is replying.
1004          *
1005          * [ABORT back to where the offender came from.]
1006          */
1007         if (chunk)
1008                 retval->transport = chunk->transport;
1009 
1010 no_mem:
1011         return retval;
1012 }
1013 
1014 /* Helper to create ABORT with a SCTP_ERROR_USER_ABORT error.  */
1015 struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *asoc,
1016                                         struct msghdr *msg,
1017                                         size_t paylen)
1018 {
1019         struct sctp_chunk *retval;
1020         void *payload = NULL;
1021         int err;
1022 
1023         retval = sctp_make_abort(asoc, NULL, sizeof(sctp_errhdr_t) + paylen);
1024         if (!retval)
1025                 goto err_chunk;
1026 
1027         if (paylen) {
1028                 /* Put the msg_iov together into payload.  */
1029                 payload = kmalloc(paylen, GFP_KERNEL);
1030                 if (!payload)
1031                         goto err_payload;
1032 
1033                 err = memcpy_from_msg(payload, msg, paylen);
1034                 if (err < 0)
1035                         goto err_copy;
1036         }
1037 
1038         sctp_init_cause(retval, SCTP_ERROR_USER_ABORT, paylen);
1039         sctp_addto_chunk(retval, paylen, payload);
1040 
1041         if (paylen)
1042                 kfree(payload);
1043 
1044         return retval;
1045 
1046 err_copy:
1047         kfree(payload);
1048 err_payload:
1049         sctp_chunk_free(retval);
1050         retval = NULL;
1051 err_chunk:
1052         return retval;
1053 }
1054 
1055 /* Append bytes to the end of a parameter.  Will panic if chunk is not big
1056  * enough.
1057  */
1058 static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
1059                               const void *data)
1060 {
1061         void *target;
1062         int chunklen = ntohs(chunk->chunk_hdr->length);
1063 
1064         target = skb_put(chunk->skb, len);
1065 
1066         if (data)
1067                 memcpy(target, data, len);
1068         else
1069                 memset(target, 0, len);
1070 
1071         /* Adjust the chunk length field.  */
1072         chunk->chunk_hdr->length = htons(chunklen + len);
1073         chunk->chunk_end = skb_tail_pointer(chunk->skb);
1074 
1075         return target;
1076 }
1077 
1078 /* Make an ABORT chunk with a PROTOCOL VIOLATION cause code. */
1079 struct sctp_chunk *sctp_make_abort_violation(
1080         const struct sctp_association *asoc,
1081         const struct sctp_chunk *chunk,
1082         const __u8   *payload,
1083         const size_t paylen)
1084 {
1085         struct sctp_chunk  *retval;
1086         struct sctp_paramhdr phdr;
1087 
1088         retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t) + paylen +
1089                                               sizeof(phdr));
1090         if (!retval)
1091                 goto end;
1092 
1093         sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, paylen +
1094                                                             sizeof(phdr));
1095 
1096         phdr.type = htons(chunk->chunk_hdr->type);
1097         phdr.length = chunk->chunk_hdr->length;
1098         sctp_addto_chunk(retval, paylen, payload);
1099         sctp_addto_param(retval, sizeof(phdr), &phdr);
1100 
1101 end:
1102         return retval;
1103 }
1104 
1105 struct sctp_chunk *sctp_make_violation_paramlen(
1106         const struct sctp_association *asoc,
1107         const struct sctp_chunk *chunk,
1108         struct sctp_paramhdr *param)
1109 {
1110         struct sctp_chunk *retval;
1111         static const char error[] = "The following parameter had invalid length:";
1112         size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t) +
1113                              sizeof(*param);
1114 
1115         retval = sctp_make_abort(asoc, chunk, payload_len);
1116         if (!retval)
1117                 goto nodata;
1118 
1119         sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION,
1120                         sizeof(error) + sizeof(*param));
1121         sctp_addto_chunk(retval, sizeof(error), error);
1122         sctp_addto_param(retval, sizeof(*param), param);
1123 
1124 nodata:
1125         return retval;
1126 }
1127 
1128 struct sctp_chunk *sctp_make_violation_max_retrans(
1129         const struct sctp_association *asoc,
1130         const struct sctp_chunk *chunk)
1131 {
1132         struct sctp_chunk *retval;
1133         static const char error[] = "Association exceeded its max_retans count";
1134         size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t);
1135 
1136         retval = sctp_make_abort(asoc, chunk, payload_len);
1137         if (!retval)
1138                 goto nodata;
1139 
1140         sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, sizeof(error));
1141         sctp_addto_chunk(retval, sizeof(error), error);
1142 
1143 nodata:
1144         return retval;
1145 }
1146 
1147 /* Make a HEARTBEAT chunk.  */
1148 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
1149                                   const struct sctp_transport *transport)
1150 {
1151         struct sctp_chunk *retval;
1152         sctp_sender_hb_info_t hbinfo;
1153 
1154         retval = sctp_make_control(asoc, SCTP_CID_HEARTBEAT, 0,
1155                                    sizeof(hbinfo), GFP_ATOMIC);
1156 
1157         if (!retval)
1158                 goto nodata;
1159 
1160         hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO;
1161         hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t));
1162         hbinfo.daddr = transport->ipaddr;
1163         hbinfo.sent_at = jiffies;
1164         hbinfo.hb_nonce = transport->hb_nonce;
1165 
1166         /* Cast away the 'const', as this is just telling the chunk
1167          * what transport it belongs to.
1168          */
1169         retval->transport = (struct sctp_transport *) transport;
1170         retval->subh.hbs_hdr = sctp_addto_chunk(retval, sizeof(hbinfo),
1171                                                 &hbinfo);
1172 
1173 nodata:
1174         return retval;
1175 }
1176 
1177 struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc,
1178                                       const struct sctp_chunk *chunk,
1179                                       const void *payload, const size_t paylen)
1180 {
1181         struct sctp_chunk *retval;
1182 
1183         retval  = sctp_make_control(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen,
1184                                     GFP_ATOMIC);
1185         if (!retval)
1186                 goto nodata;
1187 
1188         retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);
1189 
1190         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
1191          *
1192          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1193          * HEARTBEAT ACK, * etc.) to the same destination transport
1194          * address from which it * received the DATA or control chunk
1195          * to which it is replying.
1196          *
1197          * [HBACK back to where the HEARTBEAT came from.]
1198          */
1199         if (chunk)
1200                 retval->transport = chunk->transport;
1201 
1202 nodata:
1203         return retval;
1204 }
1205 
1206 /* Create an Operation Error chunk with the specified space reserved.
1207  * This routine can be used for containing multiple causes in the chunk.
1208  */
1209 static struct sctp_chunk *sctp_make_op_error_space(
1210         const struct sctp_association *asoc,
1211         const struct sctp_chunk *chunk,
1212         size_t size)
1213 {
1214         struct sctp_chunk *retval;
1215 
1216         retval = sctp_make_control(asoc, SCTP_CID_ERROR, 0,
1217                                    sizeof(sctp_errhdr_t) + size, GFP_ATOMIC);
1218         if (!retval)
1219                 goto nodata;
1220 
1221         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
1222          *
1223          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1224          * HEARTBEAT ACK, etc.) to the same destination transport
1225          * address from which it received the DATA or control chunk
1226          * to which it is replying.
1227          *
1228          */
1229         if (chunk)
1230                 retval->transport = chunk->transport;
1231 
1232 nodata:
1233         return retval;
1234 }
1235 
1236 /* Create an Operation Error chunk of a fixed size,
1237  * specifically, max(asoc->pathmtu, SCTP_DEFAULT_MAXSEGMENT)
1238  * This is a helper function to allocate an error chunk for
1239  * for those invalid parameter codes in which we may not want
1240  * to report all the errors, if the incoming chunk is large
1241  */
1242 static inline struct sctp_chunk *sctp_make_op_error_fixed(
1243         const struct sctp_association *asoc,
1244         const struct sctp_chunk *chunk)
1245 {
1246         size_t size = asoc ? asoc->pathmtu : 0;
1247 
1248         if (!size)
1249                 size = SCTP_DEFAULT_MAXSEGMENT;
1250 
1251         return sctp_make_op_error_space(asoc, chunk, size);
1252 }
1253 
1254 /* Create an Operation Error chunk.  */
1255 struct sctp_chunk *sctp_make_op_error(const struct sctp_association *asoc,
1256                                  const struct sctp_chunk *chunk,
1257                                  __be16 cause_code, const void *payload,
1258                                  size_t paylen, size_t reserve_tail)
1259 {
1260         struct sctp_chunk *retval;
1261 
1262         retval = sctp_make_op_error_space(asoc, chunk, paylen + reserve_tail);
1263         if (!retval)
1264                 goto nodata;
1265 
1266         sctp_init_cause(retval, cause_code, paylen + reserve_tail);
1267         sctp_addto_chunk(retval, paylen, payload);
1268         if (reserve_tail)
1269                 sctp_addto_param(retval, reserve_tail, NULL);
1270 
1271 nodata:
1272         return retval;
1273 }
1274 
1275 struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc)
1276 {
1277         struct sctp_chunk *retval;
1278         struct sctp_hmac *hmac_desc;
1279         struct sctp_authhdr auth_hdr;
1280         __u8 *hmac;
1281 
1282         /* Get the first hmac that the peer told us to use */
1283         hmac_desc = sctp_auth_asoc_get_hmac(asoc);
1284         if (unlikely(!hmac_desc))
1285                 return NULL;
1286 
1287         retval = sctp_make_control(asoc, SCTP_CID_AUTH, 0,
1288                         hmac_desc->hmac_len + sizeof(sctp_authhdr_t),
1289                         GFP_ATOMIC);
1290         if (!retval)
1291                 return NULL;
1292 
1293         auth_hdr.hmac_id = htons(hmac_desc->hmac_id);
1294         auth_hdr.shkey_id = htons(asoc->active_key_id);
1295 
1296         retval->subh.auth_hdr = sctp_addto_chunk(retval, sizeof(sctp_authhdr_t),
1297                                                 &auth_hdr);
1298 
1299         hmac = skb_put_zero(retval->skb, hmac_desc->hmac_len);
1300 
1301         /* Adjust the chunk header to include the empty MAC */
1302         retval->chunk_hdr->length =
1303                 htons(ntohs(retval->chunk_hdr->length) + hmac_desc->hmac_len);
1304         retval->chunk_end = skb_tail_pointer(retval->skb);
1305 
1306         return retval;
1307 }
1308 
1309 
1310 /********************************************************************
1311  * 2nd Level Abstractions
1312  ********************************************************************/
1313 
1314 /* Turn an skb into a chunk.
1315  * FIXME: Eventually move the structure directly inside the skb->cb[].
1316  *
1317  * sctpimpguide-05.txt Section 2.8.2
1318  * M1) Each time a new DATA chunk is transmitted
1319  * set the 'TSN.Missing.Report' count for that TSN to 0. The
1320  * 'TSN.Missing.Report' count will be used to determine missing chunks
1321  * and when to fast retransmit.
1322  *
1323  */
1324 struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
1325                             const struct sctp_association *asoc,
1326                             struct sock *sk, gfp_t gfp)
1327 {
1328         struct sctp_chunk *retval;
1329 
1330         retval = kmem_cache_zalloc(sctp_chunk_cachep, gfp);
1331 
1332         if (!retval)
1333                 goto nodata;
1334         if (!sk)
1335                 pr_debug("%s: chunkifying skb:%p w/o an sk\n", __func__, skb);
1336 
1337         INIT_LIST_HEAD(&retval->list);
1338         retval->skb             = skb;
1339         retval->asoc            = (struct sctp_association *)asoc;
1340         retval->singleton       = 1;
1341 
1342         retval->fast_retransmit = SCTP_CAN_FRTX;
1343 
1344         /* Polish the bead hole.  */
1345         INIT_LIST_HEAD(&retval->transmitted_list);
1346         INIT_LIST_HEAD(&retval->frag_list);
1347         SCTP_DBG_OBJCNT_INC(chunk);
1348         refcount_set(&retval->refcnt, 1);
1349 
1350 nodata:
1351         return retval;
1352 }
1353 
1354 /* Set chunk->source and dest based on the IP header in chunk->skb.  */
1355 void sctp_init_addrs(struct sctp_chunk *chunk, union sctp_addr *src,
1356                      union sctp_addr *dest)
1357 {
1358         memcpy(&chunk->source, src, sizeof(union sctp_addr));
1359         memcpy(&chunk->dest, dest, sizeof(union sctp_addr));
1360 }
1361 
1362 /* Extract the source address from a chunk.  */
1363 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk)
1364 {
1365         /* If we have a known transport, use that.  */
1366         if (chunk->transport) {
1367                 return &chunk->transport->ipaddr;
1368         } else {
1369                 /* Otherwise, extract it from the IP header.  */
1370                 return &chunk->source;
1371         }
1372 }
1373 
1374 /* Create a new chunk, setting the type and flags headers from the
1375  * arguments, reserving enough space for a 'paylen' byte payload.
1376  */
1377 static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc,
1378                                             __u8 type, __u8 flags, int paylen,
1379                                             gfp_t gfp)
1380 {
1381         struct sctp_chunk *retval;
1382         struct sctp_chunkhdr *chunk_hdr;
1383         struct sk_buff *skb;
1384         struct sock *sk;
1385 
1386         /* No need to allocate LL here, as this is only a chunk. */
1387         skb = alloc_skb(SCTP_PAD4(sizeof(*chunk_hdr) + paylen), gfp);
1388         if (!skb)
1389                 goto nodata;
1390 
1391         /* Make room for the chunk header.  */
1392         chunk_hdr = (struct sctp_chunkhdr *)skb_put(skb, sizeof(*chunk_hdr));
1393         chunk_hdr->type   = type;
1394         chunk_hdr->flags  = flags;
1395         chunk_hdr->length = htons(sizeof(*chunk_hdr));
1396 
1397         sk = asoc ? asoc->base.sk : NULL;
1398         retval = sctp_chunkify(skb, asoc, sk, gfp);
1399         if (!retval) {
1400                 kfree_skb(skb);
1401                 goto nodata;
1402         }
1403 
1404         retval->chunk_hdr = chunk_hdr;
1405         retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(*chunk_hdr);
1406 
1407         /* Determine if the chunk needs to be authenticated */
1408         if (sctp_auth_send_cid(type, asoc))
1409                 retval->auth = 1;
1410 
1411         return retval;
1412 nodata:
1413         return NULL;
1414 }
1415 
1416 static struct sctp_chunk *sctp_make_data(const struct sctp_association *asoc,
1417                                          __u8 flags, int paylen, gfp_t gfp)
1418 {
1419         return _sctp_make_chunk(asoc, SCTP_CID_DATA, flags, paylen, gfp);
1420 }
1421 
1422 static struct sctp_chunk *sctp_make_control(const struct sctp_association *asoc,
1423                                             __u8 type, __u8 flags, int paylen,
1424                                             gfp_t gfp)
1425 {
1426         struct sctp_chunk *chunk;
1427 
1428         chunk = _sctp_make_chunk(asoc, type, flags, paylen, gfp);
1429         if (chunk)
1430                 sctp_control_set_owner_w(chunk);
1431 
1432         return chunk;
1433 }
1434 
1435 /* Release the memory occupied by a chunk.  */
1436 static void sctp_chunk_destroy(struct sctp_chunk *chunk)
1437 {
1438         BUG_ON(!list_empty(&chunk->list));
1439         list_del_init(&chunk->transmitted_list);
1440 
1441         consume_skb(chunk->skb);
1442         consume_skb(chunk->auth_chunk);
1443 
1444         SCTP_DBG_OBJCNT_DEC(chunk);
1445         kmem_cache_free(sctp_chunk_cachep, chunk);
1446 }
1447 
1448 /* Possibly, free the chunk.  */
1449 void sctp_chunk_free(struct sctp_chunk *chunk)
1450 {
1451         /* Release our reference on the message tracker. */
1452         if (chunk->msg)
1453                 sctp_datamsg_put(chunk->msg);
1454 
1455         sctp_chunk_put(chunk);
1456 }
1457 
1458 /* Grab a reference to the chunk. */
1459 void sctp_chunk_hold(struct sctp_chunk *ch)
1460 {
1461         refcount_inc(&ch->refcnt);
1462 }
1463 
1464 /* Release a reference to the chunk. */
1465 void sctp_chunk_put(struct sctp_chunk *ch)
1466 {
1467         if (refcount_dec_and_test(&ch->refcnt))
1468                 sctp_chunk_destroy(ch);
1469 }
1470 
1471 /* Append bytes to the end of a chunk.  Will panic if chunk is not big
1472  * enough.
1473  */
1474 void *sctp_addto_chunk(struct sctp_chunk *chunk, int len, const void *data)
1475 {
1476         void *target;
1477         int chunklen = ntohs(chunk->chunk_hdr->length);
1478         int padlen = SCTP_PAD4(chunklen) - chunklen;
1479 
1480         skb_put_zero(chunk->skb, padlen);
1481         target = skb_put_data(chunk->skb, data, len);
1482 
1483         /* Adjust the chunk length field.  */
1484         chunk->chunk_hdr->length = htons(chunklen + padlen + len);
1485         chunk->chunk_end = skb_tail_pointer(chunk->skb);
1486 
1487         return target;
1488 }
1489 
1490 /* Append bytes to the end of a chunk. Returns NULL if there isn't sufficient
1491  * space in the chunk
1492  */
1493 static void *sctp_addto_chunk_fixed(struct sctp_chunk *chunk,
1494                                     int len, const void *data)
1495 {
1496         if (skb_tailroom(chunk->skb) >= len)
1497                 return sctp_addto_chunk(chunk, len, data);
1498         else
1499                 return NULL;
1500 }
1501 
1502 /* Append bytes from user space to the end of a chunk.  Will panic if
1503  * chunk is not big enough.
1504  * Returns a kernel err value.
1505  */
1506 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
1507                           struct iov_iter *from)
1508 {
1509         void *target;
1510 
1511         /* Make room in chunk for data.  */
1512         target = skb_put(chunk->skb, len);
1513 
1514         /* Copy data (whole iovec) into chunk */
1515         if (!copy_from_iter_full(target, len, from))
1516                 return -EFAULT;
1517 
1518         /* Adjust the chunk length field.  */
1519         chunk->chunk_hdr->length =
1520                 htons(ntohs(chunk->chunk_hdr->length) + len);
1521         chunk->chunk_end = skb_tail_pointer(chunk->skb);
1522 
1523         return 0;
1524 }
1525 
1526 /* Helper function to assign a TSN if needed.  This assumes that both
1527  * the data_hdr and association have already been assigned.
1528  */
1529 void sctp_chunk_assign_ssn(struct sctp_chunk *chunk)
1530 {
1531         struct sctp_datamsg *msg;
1532         struct sctp_chunk *lchunk;
1533         struct sctp_stream *stream;
1534         __u16 ssn;
1535         __u16 sid;
1536 
1537         if (chunk->has_ssn)
1538                 return;
1539 
1540         /* All fragments will be on the same stream */
1541         sid = ntohs(chunk->subh.data_hdr->stream);
1542         stream = &chunk->asoc->stream;
1543 
1544         /* Now assign the sequence number to the entire message.
1545          * All fragments must have the same stream sequence number.
1546          */
1547         msg = chunk->msg;
1548         list_for_each_entry(lchunk, &msg->chunks, frag_list) {
1549                 if (lchunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
1550                         ssn = 0;
1551                 } else {
1552                         if (lchunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG)
1553                                 ssn = sctp_ssn_next(stream, out, sid);
1554                         else
1555                                 ssn = sctp_ssn_peek(stream, out, sid);
1556                 }
1557 
1558                 lchunk->subh.data_hdr->ssn = htons(ssn);
1559                 lchunk->has_ssn = 1;
1560         }
1561 }
1562 
1563 /* Helper function to assign a TSN if needed.  This assumes that both
1564  * the data_hdr and association have already been assigned.
1565  */
1566 void sctp_chunk_assign_tsn(struct sctp_chunk *chunk)
1567 {
1568         if (!chunk->has_tsn) {
1569                 /* This is the last possible instant to
1570                  * assign a TSN.
1571                  */
1572                 chunk->subh.data_hdr->tsn =
1573                         htonl(sctp_association_get_next_tsn(chunk->asoc));
1574                 chunk->has_tsn = 1;
1575         }
1576 }
1577 
1578 /* Create a CLOSED association to use with an incoming packet.  */
1579 struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *ep,
1580                                         struct sctp_chunk *chunk,
1581                                         gfp_t gfp)
1582 {
1583         struct sctp_association *asoc;
1584         struct sk_buff *skb;
1585         sctp_scope_t scope;
1586 
1587         /* Create the bare association.  */
1588         scope = sctp_scope(sctp_source(chunk));
1589         asoc = sctp_association_new(ep, ep->base.sk, scope, gfp);
1590         if (!asoc)
1591                 goto nodata;
1592         asoc->temp = 1;
1593         skb = chunk->skb;
1594         /* Create an entry for the source address of the packet.  */
1595         SCTP_INPUT_CB(skb)->af->from_skb(&asoc->c.peer_addr, skb, 1);
1596 
1597 nodata:
1598         return asoc;
1599 }
1600 
1601 /* Build a cookie representing asoc.
1602  * This INCLUDES the param header needed to put the cookie in the INIT ACK.
1603  */
1604 static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
1605                                       const struct sctp_association *asoc,
1606                                       const struct sctp_chunk *init_chunk,
1607                                       int *cookie_len,
1608                                       const __u8 *raw_addrs, int addrs_len)
1609 {
1610         sctp_cookie_param_t *retval;
1611         struct sctp_signed_cookie *cookie;
1612         int headersize, bodysize;
1613 
1614         /* Header size is static data prior to the actual cookie, including
1615          * any padding.
1616          */
1617         headersize = sizeof(struct sctp_paramhdr) +
1618                      (sizeof(struct sctp_signed_cookie) -
1619                       sizeof(struct sctp_cookie));
1620         bodysize = sizeof(struct sctp_cookie)
1621                 + ntohs(init_chunk->chunk_hdr->length) + addrs_len;
1622 
1623         /* Pad out the cookie to a multiple to make the signature
1624          * functions simpler to write.
1625          */
1626         if (bodysize % SCTP_COOKIE_MULTIPLE)
1627                 bodysize += SCTP_COOKIE_MULTIPLE
1628                         - (bodysize % SCTP_COOKIE_MULTIPLE);
1629         *cookie_len = headersize + bodysize;
1630 
1631         /* Clear this memory since we are sending this data structure
1632          * out on the network.
1633          */
1634         retval = kzalloc(*cookie_len, GFP_ATOMIC);
1635         if (!retval)
1636                 goto nodata;
1637 
1638         cookie = (struct sctp_signed_cookie *) retval->body;
1639 
1640         /* Set up the parameter header.  */
1641         retval->p.type = SCTP_PARAM_STATE_COOKIE;
1642         retval->p.length = htons(*cookie_len);
1643 
1644         /* Copy the cookie part of the association itself.  */
1645         cookie->c = asoc->c;
1646         /* Save the raw address list length in the cookie. */
1647         cookie->c.raw_addr_list_len = addrs_len;
1648 
1649         /* Remember PR-SCTP capability. */
1650         cookie->c.prsctp_capable = asoc->peer.prsctp_capable;
1651 
1652         /* Save adaptation indication in the cookie. */
1653         cookie->c.adaptation_ind = asoc->peer.adaptation_ind;
1654 
1655         /* Set an expiration time for the cookie.  */
1656         cookie->c.expiration = ktime_add(asoc->cookie_life,
1657                                          ktime_get_real());
1658 
1659         /* Copy the peer's init packet.  */
1660         memcpy(&cookie->c.peer_init[0], init_chunk->chunk_hdr,
1661                ntohs(init_chunk->chunk_hdr->length));
1662 
1663         /* Copy the raw local address list of the association. */
1664         memcpy((__u8 *)&cookie->c.peer_init[0] +
1665                ntohs(init_chunk->chunk_hdr->length), raw_addrs, addrs_len);
1666 
1667         if (sctp_sk(ep->base.sk)->hmac) {
1668                 SHASH_DESC_ON_STACK(desc, sctp_sk(ep->base.sk)->hmac);
1669                 int err;
1670 
1671                 /* Sign the message.  */
1672                 desc->tfm = sctp_sk(ep->base.sk)->hmac;
1673                 desc->flags = 0;
1674 
1675                 err = crypto_shash_setkey(desc->tfm, ep->secret_key,
1676                                           sizeof(ep->secret_key)) ?:
1677                       crypto_shash_digest(desc, (u8 *)&cookie->c, bodysize,
1678                                           cookie->signature);
1679                 shash_desc_zero(desc);
1680                 if (err)
1681                         goto free_cookie;
1682         }
1683 
1684         return retval;
1685 
1686 free_cookie:
1687         kfree(retval);
1688 nodata:
1689         *cookie_len = 0;
1690         return NULL;
1691 }
1692 
1693 /* Unpack the cookie from COOKIE ECHO chunk, recreating the association.  */
1694 struct sctp_association *sctp_unpack_cookie(
1695         const struct sctp_endpoint *ep,
1696         const struct sctp_association *asoc,
1697         struct sctp_chunk *chunk, gfp_t gfp,
1698         int *error, struct sctp_chunk **errp)
1699 {
1700         struct sctp_association *retval = NULL;
1701         struct sctp_signed_cookie *cookie;
1702         struct sctp_cookie *bear_cookie;
1703         int headersize, bodysize, fixed_size;
1704         __u8 *digest = ep->digest;
1705         unsigned int len;
1706         sctp_scope_t scope;
1707         struct sk_buff *skb = chunk->skb;
1708         ktime_t kt;
1709 
1710         /* Header size is static data prior to the actual cookie, including
1711          * any padding.
1712          */
1713         headersize = sizeof(struct sctp_chunkhdr) +
1714                      (sizeof(struct sctp_signed_cookie) -
1715                       sizeof(struct sctp_cookie));
1716         bodysize = ntohs(chunk->chunk_hdr->length) - headersize;
1717         fixed_size = headersize + sizeof(struct sctp_cookie);
1718 
1719         /* Verify that the chunk looks like it even has a cookie.
1720          * There must be enough room for our cookie and our peer's
1721          * INIT chunk.
1722          */
1723         len = ntohs(chunk->chunk_hdr->length);
1724         if (len < fixed_size + sizeof(struct sctp_chunkhdr))
1725                 goto malformed;
1726 
1727         /* Verify that the cookie has been padded out. */
1728         if (bodysize % SCTP_COOKIE_MULTIPLE)
1729                 goto malformed;
1730 
1731         /* Process the cookie.  */
1732         cookie = chunk->subh.cookie_hdr;
1733         bear_cookie = &cookie->c;
1734 
1735         if (!sctp_sk(ep->base.sk)->hmac)
1736                 goto no_hmac;
1737 
1738         /* Check the signature.  */
1739         {
1740                 SHASH_DESC_ON_STACK(desc, sctp_sk(ep->base.sk)->hmac);
1741                 int err;
1742 
1743                 desc->tfm = sctp_sk(ep->base.sk)->hmac;
1744                 desc->flags = 0;
1745 
1746                 err = crypto_shash_setkey(desc->tfm, ep->secret_key,
1747                                           sizeof(ep->secret_key)) ?:
1748                       crypto_shash_digest(desc, (u8 *)bear_cookie, bodysize,
1749                                           digest);
1750                 shash_desc_zero(desc);
1751 
1752                 if (err) {
1753                         *error = -SCTP_IERROR_NOMEM;
1754                         goto fail;
1755                 }
1756         }
1757 
1758         if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
1759                 *error = -SCTP_IERROR_BAD_SIG;
1760                 goto fail;
1761         }
1762 
1763 no_hmac:
1764         /* IG Section 2.35.2:
1765          *  3) Compare the port numbers and the verification tag contained
1766          *     within the COOKIE ECHO chunk to the actual port numbers and the
1767          *     verification tag within the SCTP common header of the received
1768          *     packet. If these values do not match the packet MUST be silently
1769          *     discarded,
1770          */
1771         if (ntohl(chunk->sctp_hdr->vtag) != bear_cookie->my_vtag) {
1772                 *error = -SCTP_IERROR_BAD_TAG;
1773                 goto fail;
1774         }
1775 
1776         if (chunk->sctp_hdr->source != bear_cookie->peer_addr.v4.sin_port ||
1777             ntohs(chunk->sctp_hdr->dest) != bear_cookie->my_port) {
1778                 *error = -SCTP_IERROR_BAD_PORTS;
1779                 goto fail;
1780         }
1781 
1782         /* Check to see if the cookie is stale.  If there is already
1783          * an association, there is no need to check cookie's expiration
1784          * for init collision case of lost COOKIE ACK.
1785          * If skb has been timestamped, then use the stamp, otherwise
1786          * use current time.  This introduces a small possibility that
1787          * that a cookie may be considered expired, but his would only slow
1788          * down the new association establishment instead of every packet.
1789          */
1790         if (sock_flag(ep->base.sk, SOCK_TIMESTAMP))
1791                 kt = skb_get_ktime(skb);
1792         else
1793                 kt = ktime_get_real();
1794 
1795         if (!asoc && ktime_before(bear_cookie->expiration, kt)) {
1796                 /*
1797                  * Section 3.3.10.3 Stale Cookie Error (3)
1798                  *
1799                  * Cause of error
1800                  * ---------------
1801                  * Stale Cookie Error:  Indicates the receipt of a valid State
1802                  * Cookie that has expired.
1803                  */
1804                 len = ntohs(chunk->chunk_hdr->length);
1805                 *errp = sctp_make_op_error_space(asoc, chunk, len);
1806                 if (*errp) {
1807                         suseconds_t usecs = ktime_to_us(ktime_sub(kt, bear_cookie->expiration));
1808                         __be32 n = htonl(usecs);
1809 
1810                         sctp_init_cause(*errp, SCTP_ERROR_STALE_COOKIE,
1811                                         sizeof(n));
1812                         sctp_addto_chunk(*errp, sizeof(n), &n);
1813                         *error = -SCTP_IERROR_STALE_COOKIE;
1814                 } else
1815                         *error = -SCTP_IERROR_NOMEM;
1816 
1817                 goto fail;
1818         }
1819 
1820         /* Make a new base association.  */
1821         scope = sctp_scope(sctp_source(chunk));
1822         retval = sctp_association_new(ep, ep->base.sk, scope, gfp);
1823         if (!retval) {
1824                 *error = -SCTP_IERROR_NOMEM;
1825                 goto fail;
1826         }
1827 
1828         /* Set up our peer's port number.  */
1829         retval->peer.port = ntohs(chunk->sctp_hdr->source);
1830 
1831         /* Populate the association from the cookie.  */
1832         memcpy(&retval->c, bear_cookie, sizeof(*bear_cookie));
1833 
1834         if (sctp_assoc_set_bind_addr_from_cookie(retval, bear_cookie,
1835                                                  GFP_ATOMIC) < 0) {
1836                 *error = -SCTP_IERROR_NOMEM;
1837                 goto fail;
1838         }
1839 
1840         /* Also, add the destination address. */
1841         if (list_empty(&retval->base.bind_addr.address_list)) {
1842                 sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest,
1843                                    sizeof(chunk->dest), SCTP_ADDR_SRC,
1844                                    GFP_ATOMIC);
1845         }
1846 
1847         retval->next_tsn = retval->c.initial_tsn;
1848         retval->ctsn_ack_point = retval->next_tsn - 1;
1849         retval->addip_serial = retval->c.initial_tsn;
1850         retval->strreset_outseq = retval->c.initial_tsn;
1851         retval->adv_peer_ack_point = retval->ctsn_ack_point;
1852         retval->peer.prsctp_capable = retval->c.prsctp_capable;
1853         retval->peer.adaptation_ind = retval->c.adaptation_ind;
1854 
1855         /* The INIT stuff will be done by the side effects.  */
1856         return retval;
1857 
1858 fail:
1859         if (retval)
1860                 sctp_association_free(retval);
1861 
1862         return NULL;
1863 
1864 malformed:
1865         /* Yikes!  The packet is either corrupt or deliberately
1866          * malformed.
1867          */
1868         *error = -SCTP_IERROR_MALFORMED;
1869         goto fail;
1870 }
1871 
1872 /********************************************************************
1873  * 3rd Level Abstractions
1874  ********************************************************************/
1875 
1876 struct __sctp_missing {
1877         __be32 num_missing;
1878         __be16 type;
1879 }  __packed;
1880 
1881 /*
1882  * Report a missing mandatory parameter.
1883  */
1884 static int sctp_process_missing_param(const struct sctp_association *asoc,
1885                                       enum sctp_param paramtype,
1886                                       struct sctp_chunk *chunk,
1887                                       struct sctp_chunk **errp)
1888 {
1889         struct __sctp_missing report;
1890         __u16 len;
1891 
1892         len = SCTP_PAD4(sizeof(report));
1893 
1894         /* Make an ERROR chunk, preparing enough room for
1895          * returning multiple unknown parameters.
1896          */
1897         if (!*errp)
1898                 *errp = sctp_make_op_error_space(asoc, chunk, len);
1899 
1900         if (*errp) {
1901                 report.num_missing = htonl(1);
1902                 report.type = paramtype;
1903                 sctp_init_cause(*errp, SCTP_ERROR_MISS_PARAM,
1904                                 sizeof(report));
1905                 sctp_addto_chunk(*errp, sizeof(report), &report);
1906         }
1907 
1908         /* Stop processing this chunk. */
1909         return 0;
1910 }
1911 
1912 /* Report an Invalid Mandatory Parameter.  */
1913 static int sctp_process_inv_mandatory(const struct sctp_association *asoc,
1914                                       struct sctp_chunk *chunk,
1915                                       struct sctp_chunk **errp)
1916 {
1917         /* Invalid Mandatory Parameter Error has no payload. */
1918 
1919         if (!*errp)
1920                 *errp = sctp_make_op_error_space(asoc, chunk, 0);
1921 
1922         if (*errp)
1923                 sctp_init_cause(*errp, SCTP_ERROR_INV_PARAM, 0);
1924 
1925         /* Stop processing this chunk. */
1926         return 0;
1927 }
1928 
1929 static int sctp_process_inv_paramlength(const struct sctp_association *asoc,
1930                                         struct sctp_paramhdr *param,
1931                                         const struct sctp_chunk *chunk,
1932                                         struct sctp_chunk **errp)
1933 {
1934         /* This is a fatal error.  Any accumulated non-fatal errors are
1935          * not reported.
1936          */
1937         if (*errp)
1938                 sctp_chunk_free(*errp);
1939 
1940         /* Create an error chunk and fill it in with our payload. */
1941         *errp = sctp_make_violation_paramlen(asoc, chunk, param);
1942 
1943         return 0;
1944 }
1945 
1946 
1947 /* Do not attempt to handle the HOST_NAME parm.  However, do
1948  * send back an indicator to the peer.
1949  */
1950 static int sctp_process_hn_param(const struct sctp_association *asoc,
1951                                  union sctp_params param,
1952                                  struct sctp_chunk *chunk,
1953                                  struct sctp_chunk **errp)
1954 {
1955         __u16 len = ntohs(param.p->length);
1956 
1957         /* Processing of the HOST_NAME parameter will generate an
1958          * ABORT.  If we've accumulated any non-fatal errors, they
1959          * would be unrecognized parameters and we should not include
1960          * them in the ABORT.
1961          */
1962         if (*errp)
1963                 sctp_chunk_free(*errp);
1964 
1965         *errp = sctp_make_op_error_space(asoc, chunk, len);
1966 
1967         if (*errp) {
1968                 sctp_init_cause(*errp, SCTP_ERROR_DNS_FAILED, len);
1969                 sctp_addto_chunk(*errp, len, param.v);
1970         }
1971 
1972         /* Stop processing this chunk. */
1973         return 0;
1974 }
1975 
1976 static int sctp_verify_ext_param(struct net *net, union sctp_params param)
1977 {
1978         __u16 num_ext = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
1979         int have_auth = 0;
1980         int have_asconf = 0;
1981         int i;
1982 
1983         for (i = 0; i < num_ext; i++) {
1984                 switch (param.ext->chunks[i]) {
1985                 case SCTP_CID_AUTH:
1986                         have_auth = 1;
1987                         break;
1988                 case SCTP_CID_ASCONF:
1989                 case SCTP_CID_ASCONF_ACK:
1990                         have_asconf = 1;
1991                         break;
1992                 }
1993         }
1994 
1995         /* ADD-IP Security: The draft requires us to ABORT or ignore the
1996          * INIT/INIT-ACK if ADD-IP is listed, but AUTH is not.  Do this
1997          * only if ADD-IP is turned on and we are not backward-compatible
1998          * mode.
1999          */
2000         if (net->sctp.addip_noauth)
2001                 return 1;
2002 
2003         if (net->sctp.addip_enable && !have_auth && have_asconf)
2004                 return 0;
2005 
2006         return 1;
2007 }
2008 
2009 static void sctp_process_ext_param(struct sctp_association *asoc,
2010                                     union sctp_params param)
2011 {
2012         struct net *net = sock_net(asoc->base.sk);
2013         __u16 num_ext = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
2014         int i;
2015 
2016         for (i = 0; i < num_ext; i++) {
2017                 switch (param.ext->chunks[i]) {
2018                 case SCTP_CID_RECONF:
2019                         if (asoc->reconf_enable &&
2020                             !asoc->peer.reconf_capable)
2021                                 asoc->peer.reconf_capable = 1;
2022                         break;
2023                 case SCTP_CID_FWD_TSN:
2024                         if (asoc->prsctp_enable && !asoc->peer.prsctp_capable)
2025                                 asoc->peer.prsctp_capable = 1;
2026                         break;
2027                 case SCTP_CID_AUTH:
2028                         /* if the peer reports AUTH, assume that he
2029                          * supports AUTH.
2030                          */
2031                         if (asoc->ep->auth_enable)
2032                                 asoc->peer.auth_capable = 1;
2033                         break;
2034                 case SCTP_CID_ASCONF:
2035                 case SCTP_CID_ASCONF_ACK:
2036                         if (net->sctp.addip_enable)
2037                                 asoc->peer.asconf_capable = 1;
2038                         break;
2039                 default:
2040                         break;
2041                 }
2042         }
2043 }
2044 
2045 /* RFC 3.2.1 & the Implementers Guide 2.2.
2046  *
2047  * The Parameter Types are encoded such that the
2048  * highest-order two bits specify the action that must be
2049  * taken if the processing endpoint does not recognize the
2050  * Parameter Type.
2051  *
2052  * 00 - Stop processing this parameter; do not process any further
2053  *      parameters within this chunk
2054  *
2055  * 01 - Stop processing this parameter, do not process any further
2056  *      parameters within this chunk, and report the unrecognized
2057  *      parameter in an 'Unrecognized Parameter' ERROR chunk.
2058  *
2059  * 10 - Skip this parameter and continue processing.
2060  *
2061  * 11 - Skip this parameter and continue processing but
2062  *      report the unrecognized parameter in an
2063  *      'Unrecognized Parameter' ERROR chunk.
2064  *
2065  * Return value:
2066  *      SCTP_IERROR_NO_ERROR - continue with the chunk
2067  *      SCTP_IERROR_ERROR    - stop and report an error.
2068  *      SCTP_IERROR_NOMEME   - out of memory.
2069  */
2070 static sctp_ierror_t sctp_process_unk_param(const struct sctp_association *asoc,
2071                                             union sctp_params param,
2072                                             struct sctp_chunk *chunk,
2073                                             struct sctp_chunk **errp)
2074 {
2075         int retval = SCTP_IERROR_NO_ERROR;
2076 
2077         switch (param.p->type & SCTP_PARAM_ACTION_MASK) {
2078         case SCTP_PARAM_ACTION_DISCARD:
2079                 retval =  SCTP_IERROR_ERROR;
2080                 break;
2081         case SCTP_PARAM_ACTION_SKIP:
2082                 break;
2083         case SCTP_PARAM_ACTION_DISCARD_ERR:
2084                 retval =  SCTP_IERROR_ERROR;
2085                 /* Fall through */
2086         case SCTP_PARAM_ACTION_SKIP_ERR:
2087                 /* Make an ERROR chunk, preparing enough room for
2088                  * returning multiple unknown parameters.
2089                  */
2090                 if (NULL == *errp)
2091                         *errp = sctp_make_op_error_fixed(asoc, chunk);
2092 
2093                 if (*errp) {
2094                         if (!sctp_init_cause_fixed(*errp, SCTP_ERROR_UNKNOWN_PARAM,
2095                                         SCTP_PAD4(ntohs(param.p->length))))
2096                                 sctp_addto_chunk_fixed(*errp,
2097                                                 SCTP_PAD4(ntohs(param.p->length)),
2098                                                 param.v);
2099                 } else {
2100                         /* If there is no memory for generating the ERROR
2101                          * report as specified, an ABORT will be triggered
2102                          * to the peer and the association won't be
2103                          * established.
2104                          */
2105                         retval = SCTP_IERROR_NOMEM;
2106                 }
2107                 break;
2108         default:
2109                 break;
2110         }
2111 
2112         return retval;
2113 }
2114 
2115 /* Verify variable length parameters
2116  * Return values:
2117  *      SCTP_IERROR_ABORT - trigger an ABORT
2118  *      SCTP_IERROR_NOMEM - out of memory (abort)
2119  *      SCTP_IERROR_ERROR - stop processing, trigger an ERROR
2120  *      SCTP_IERROR_NO_ERROR - continue with the chunk
2121  */
2122 static sctp_ierror_t sctp_verify_param(struct net *net,
2123                                         const struct sctp_endpoint *ep,
2124                                         const struct sctp_association *asoc,
2125                                         union sctp_params param,
2126                                         enum sctp_cid cid,
2127                                         struct sctp_chunk *chunk,
2128                                         struct sctp_chunk **err_chunk)
2129 {
2130         struct sctp_hmac_algo_param *hmacs;
2131         int retval = SCTP_IERROR_NO_ERROR;
2132         __u16 n_elt, id = 0;
2133         int i;
2134 
2135         /* FIXME - This routine is not looking at each parameter per the
2136          * chunk type, i.e., unrecognized parameters should be further
2137          * identified based on the chunk id.
2138          */
2139 
2140         switch (param.p->type) {
2141         case SCTP_PARAM_IPV4_ADDRESS:
2142         case SCTP_PARAM_IPV6_ADDRESS:
2143         case SCTP_PARAM_COOKIE_PRESERVATIVE:
2144         case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2145         case SCTP_PARAM_STATE_COOKIE:
2146         case SCTP_PARAM_HEARTBEAT_INFO:
2147         case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2148         case SCTP_PARAM_ECN_CAPABLE:
2149         case SCTP_PARAM_ADAPTATION_LAYER_IND:
2150                 break;
2151 
2152         case SCTP_PARAM_SUPPORTED_EXT:
2153                 if (!sctp_verify_ext_param(net, param))
2154                         return SCTP_IERROR_ABORT;
2155                 break;
2156 
2157         case SCTP_PARAM_SET_PRIMARY:
2158                 if (net->sctp.addip_enable)
2159                         break;
2160                 goto fallthrough;
2161 
2162         case SCTP_PARAM_HOST_NAME_ADDRESS:
2163                 /* Tell the peer, we won't support this param.  */
2164                 sctp_process_hn_param(asoc, param, chunk, err_chunk);
2165                 retval = SCTP_IERROR_ABORT;
2166                 break;
2167 
2168         case SCTP_PARAM_FWD_TSN_SUPPORT:
2169                 if (ep->prsctp_enable)
2170                         break;
2171                 goto fallthrough;
2172 
2173         case SCTP_PARAM_RANDOM:
2174                 if (!ep->auth_enable)
2175                         goto fallthrough;
2176 
2177                 /* SCTP-AUTH: Secion 6.1
2178                  * If the random number is not 32 byte long the association
2179                  * MUST be aborted.  The ABORT chunk SHOULD contain the error
2180                  * cause 'Protocol Violation'.
2181                  */
2182                 if (SCTP_AUTH_RANDOM_LENGTH !=
2183                         ntohs(param.p->length) - sizeof(struct sctp_paramhdr)) {
2184                         sctp_process_inv_paramlength(asoc, param.p,
2185                                                         chunk, err_chunk);
2186                         retval = SCTP_IERROR_ABORT;
2187                 }
2188                 break;
2189 
2190         case SCTP_PARAM_CHUNKS:
2191                 if (!ep->auth_enable)
2192                         goto fallthrough;
2193 
2194                 /* SCTP-AUTH: Section 3.2
2195                  * The CHUNKS parameter MUST be included once in the INIT or
2196                  *  INIT-ACK chunk if the sender wants to receive authenticated
2197                  *  chunks.  Its maximum length is 260 bytes.
2198                  */
2199                 if (260 < ntohs(param.p->length)) {
2200                         sctp_process_inv_paramlength(asoc, param.p,
2201                                                      chunk, err_chunk);
2202                         retval = SCTP_IERROR_ABORT;
2203                 }
2204                 break;
2205 
2206         case SCTP_PARAM_HMAC_ALGO:
2207                 if (!ep->auth_enable)
2208                         goto fallthrough;
2209 
2210                 hmacs = (struct sctp_hmac_algo_param *)param.p;
2211                 n_elt = (ntohs(param.p->length) -
2212                          sizeof(struct sctp_paramhdr)) >> 1;
2213 
2214                 /* SCTP-AUTH: Section 6.1
2215                  * The HMAC algorithm based on SHA-1 MUST be supported and
2216                  * included in the HMAC-ALGO parameter.
2217                  */
2218                 for (i = 0; i < n_elt; i++) {
2219                         id = ntohs(hmacs->hmac_ids[i]);
2220 
2221                         if (id == SCTP_AUTH_HMAC_ID_SHA1)
2222                                 break;
2223                 }
2224 
2225                 if (id != SCTP_AUTH_HMAC_ID_SHA1) {
2226                         sctp_process_inv_paramlength(asoc, param.p, chunk,
2227                                                      err_chunk);
2228                         retval = SCTP_IERROR_ABORT;
2229                 }
2230                 break;
2231 fallthrough:
2232         default:
2233                 pr_debug("%s: unrecognized param:%d for chunk:%d\n",
2234                          __func__, ntohs(param.p->type), cid);
2235 
2236                 retval = sctp_process_unk_param(asoc, param, chunk, err_chunk);
2237                 break;
2238         }
2239         return retval;
2240 }
2241 
2242 /* Verify the INIT packet before we process it.  */
2243 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
2244                      const struct sctp_association *asoc, enum sctp_cid cid,
2245                      struct sctp_init_chunk *peer_init,
2246                      struct sctp_chunk *chunk, struct sctp_chunk **errp)
2247 {
2248         union sctp_params param;
2249         bool has_cookie = false;
2250         int result;
2251 
2252         /* Check for missing mandatory parameters. Note: Initial TSN is
2253          * also mandatory, but is not checked here since the valid range
2254          * is 0..2**32-1. RFC4960, section 3.3.3.
2255          */
2256         if (peer_init->init_hdr.num_outbound_streams == 0 ||
2257             peer_init->init_hdr.num_inbound_streams == 0 ||
2258             peer_init->init_hdr.init_tag == 0 ||
2259             ntohl(peer_init->init_hdr.a_rwnd) < SCTP_DEFAULT_MINWINDOW)
2260                 return sctp_process_inv_mandatory(asoc, chunk, errp);
2261 
2262         sctp_walk_params(param, peer_init, init_hdr.params) {
2263                 if (param.p->type == SCTP_PARAM_STATE_COOKIE)
2264                         has_cookie = true;
2265         }
2266 
2267         /* There is a possibility that a parameter length was bad and
2268          * in that case we would have stoped walking the parameters.
2269          * The current param.p would point at the bad one.
2270          * Current consensus on the mailing list is to generate a PROTOCOL
2271          * VIOLATION error.  We build the ERROR chunk here and let the normal
2272          * error handling code build and send the packet.
2273          */
2274         if (param.v != (void *)chunk->chunk_end)
2275                 return sctp_process_inv_paramlength(asoc, param.p, chunk, errp);
2276 
2277         /* The only missing mandatory param possible today is
2278          * the state cookie for an INIT-ACK chunk.
2279          */
2280         if ((SCTP_CID_INIT_ACK == cid) && !has_cookie)
2281                 return sctp_process_missing_param(asoc, SCTP_PARAM_STATE_COOKIE,
2282                                                   chunk, errp);
2283 
2284         /* Verify all the variable length parameters */
2285         sctp_walk_params(param, peer_init, init_hdr.params) {
2286                 result = sctp_verify_param(net, ep, asoc, param, cid,
2287                                            chunk, errp);
2288                 switch (result) {
2289                 case SCTP_IERROR_ABORT:
2290                 case SCTP_IERROR_NOMEM:
2291                         return 0;
2292                 case SCTP_IERROR_ERROR:
2293                         return 1;
2294                 case SCTP_IERROR_NO_ERROR:
2295                 default:
2296                         break;
2297                 }
2298 
2299         } /* for (loop through all parameters) */
2300 
2301         return 1;
2302 }
2303 
2304 /* Unpack the parameters in an INIT packet into an association.
2305  * Returns 0 on failure, else success.
2306  * FIXME:  This is an association method.
2307  */
2308 int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,
2309                       const union sctp_addr *peer_addr,
2310                       struct sctp_init_chunk *peer_init, gfp_t gfp)
2311 {
2312         struct net *net = sock_net(asoc->base.sk);
2313         union sctp_params param;
2314         struct sctp_transport *transport;
2315         struct list_head *pos, *temp;
2316         struct sctp_af *af;
2317         union sctp_addr addr;
2318         char *cookie;
2319         int src_match = 0;
2320 
2321         /* We must include the address that the INIT packet came from.
2322          * This is the only address that matters for an INIT packet.
2323          * When processing a COOKIE ECHO, we retrieve the from address
2324          * of the INIT from the cookie.
2325          */
2326 
2327         /* This implementation defaults to making the first transport
2328          * added as the primary transport.  The source address seems to
2329          * be a a better choice than any of the embedded addresses.
2330          */
2331         if (!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
2332                 goto nomem;
2333 
2334         if (sctp_cmp_addr_exact(sctp_source(chunk), peer_addr))
2335                 src_match = 1;
2336 
2337         /* Process the initialization parameters.  */
2338         sctp_walk_params(param, peer_init, init_hdr.params) {
2339                 if (!src_match && (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
2340                     param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
2341                         af = sctp_get_af_specific(param_type2af(param.p->type));
2342                         af->from_addr_param(&addr, param.addr,
2343                                             chunk->sctp_hdr->source, 0);
2344                         if (sctp_cmp_addr_exact(sctp_source(chunk), &addr))
2345                                 src_match = 1;
2346                 }
2347 
2348                 if (!sctp_process_param(asoc, param, peer_addr, gfp))
2349                         goto clean_up;
2350         }
2351 
2352         /* source address of chunk may not match any valid address */
2353         if (!src_match)
2354                 goto clean_up;
2355 
2356         /* AUTH: After processing the parameters, make sure that we
2357          * have all the required info to potentially do authentications.
2358          */
2359         if (asoc->peer.auth_capable && (!asoc->peer.peer_random ||
2360                                         !asoc->peer.peer_hmacs))
2361                 asoc->peer.auth_capable = 0;
2362 
2363         /* In a non-backward compatible mode, if the peer claims
2364          * support for ADD-IP but not AUTH,  the ADD-IP spec states
2365          * that we MUST ABORT the association. Section 6.  The section
2366          * also give us an option to silently ignore the packet, which
2367          * is what we'll do here.
2368          */
2369         if (!net->sctp.addip_noauth &&
2370              (asoc->peer.asconf_capable && !asoc->peer.auth_capable)) {
2371                 asoc->peer.addip_disabled_mask |= (SCTP_PARAM_ADD_IP |
2372                                                   SCTP_PARAM_DEL_IP |
2373                                                   SCTP_PARAM_SET_PRIMARY);
2374                 asoc->peer.asconf_capable = 0;
2375                 goto clean_up;
2376         }
2377 
2378         /* Walk list of transports, removing transports in the UNKNOWN state. */
2379         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2380                 transport = list_entry(pos, struct sctp_transport, transports);
2381                 if (transport->state == SCTP_UNKNOWN) {
2382                         sctp_assoc_rm_peer(asoc, transport);
2383                 }
2384         }
2385 
2386         /* The fixed INIT headers are always in network byte
2387          * order.
2388          */
2389         asoc->peer.i.init_tag =
2390                 ntohl(peer_init->init_hdr.init_tag);
2391         asoc->peer.i.a_rwnd =
2392                 ntohl(peer_init->init_hdr.a_rwnd);
2393         asoc->peer.i.num_outbound_streams =
2394                 ntohs(peer_init->init_hdr.num_outbound_streams);
2395         asoc->peer.i.num_inbound_streams =
2396                 ntohs(peer_init->init_hdr.num_inbound_streams);
2397         asoc->peer.i.initial_tsn =
2398                 ntohl(peer_init->init_hdr.initial_tsn);
2399 
2400         asoc->strreset_inseq = asoc->peer.i.initial_tsn;
2401 
2402         /* Apply the upper bounds for output streams based on peer's
2403          * number of inbound streams.
2404          */
2405         if (asoc->c.sinit_num_ostreams  >
2406             ntohs(peer_init->init_hdr.num_inbound_streams)) {
2407                 asoc->c.sinit_num_ostreams =
2408                         ntohs(peer_init->init_hdr.num_inbound_streams);
2409         }
2410 
2411         if (asoc->c.sinit_max_instreams >
2412             ntohs(peer_init->init_hdr.num_outbound_streams)) {
2413                 asoc->c.sinit_max_instreams =
2414                         ntohs(peer_init->init_hdr.num_outbound_streams);
2415         }
2416 
2417         /* Copy Initiation tag from INIT to VT_peer in cookie.   */
2418         asoc->c.peer_vtag = asoc->peer.i.init_tag;
2419 
2420         /* Peer Rwnd   : Current calculated value of the peer's rwnd.  */
2421         asoc->peer.rwnd = asoc->peer.i.a_rwnd;
2422 
2423         /* Copy cookie in case we need to resend COOKIE-ECHO. */
2424         cookie = asoc->peer.cookie;
2425         if (cookie) {
2426                 asoc->peer.cookie = kmemdup(cookie, asoc->peer.cookie_len, gfp);
2427                 if (!asoc->peer.cookie)
2428                         goto clean_up;
2429         }
2430 
2431         /* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily
2432          * high (for example, implementations MAY use the size of the receiver
2433          * advertised window).
2434          */
2435         list_for_each_entry(transport, &asoc->peer.transport_addr_list,
2436                         transports) {
2437                 transport->ssthresh = asoc->peer.i.a_rwnd;
2438         }
2439 
2440         /* Set up the TSN tracking pieces.  */
2441         if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
2442                                 asoc->peer.i.initial_tsn, gfp))
2443                 goto clean_up;
2444 
2445         /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
2446          *
2447          * The stream sequence number in all the streams shall start
2448          * from 0 when the association is established.  Also, when the
2449          * stream sequence number reaches the value 65535 the next
2450          * stream sequence number shall be set to 0.
2451          */
2452 
2453         if (sctp_stream_init(&asoc->stream, asoc->c.sinit_num_ostreams,
2454                              asoc->c.sinit_max_instreams, gfp))
2455                 goto clean_up;
2456 
2457         if (!asoc->temp && sctp_assoc_set_id(asoc, gfp))
2458                 goto clean_up;
2459 
2460         /* ADDIP Section 4.1 ASCONF Chunk Procedures
2461          *
2462          * When an endpoint has an ASCONF signaled change to be sent to the
2463          * remote endpoint it should do the following:
2464          * ...
2465          * A2) A serial number should be assigned to the Chunk. The serial
2466          * number should be a monotonically increasing number. All serial
2467          * numbers are defined to be initialized at the start of the
2468          * association to the same value as the Initial TSN.
2469          */
2470         asoc->peer.addip_serial = asoc->peer.i.initial_tsn - 1;
2471         return 1;
2472 
2473 clean_up:
2474         /* Release the transport structures. */
2475         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2476                 transport = list_entry(pos, struct sctp_transport, transports);
2477                 if (transport->state != SCTP_ACTIVE)
2478                         sctp_assoc_rm_peer(asoc, transport);
2479         }
2480 
2481 nomem:
2482         return 0;
2483 }
2484 
2485 
2486 /* Update asoc with the option described in param.
2487  *
2488  * RFC2960 3.3.2.1 Optional/Variable Length Parameters in INIT
2489  *
2490  * asoc is the association to update.
2491  * param is the variable length parameter to use for update.
2492  * cid tells us if this is an INIT, INIT ACK or COOKIE ECHO.
2493  * If the current packet is an INIT we want to minimize the amount of
2494  * work we do.  In particular, we should not build transport
2495  * structures for the addresses.
2496  */
2497 static int sctp_process_param(struct sctp_association *asoc,
2498                               union sctp_params param,
2499                               const union sctp_addr *peer_addr,
2500                               gfp_t gfp)
2501 {
2502         struct net *net = sock_net(asoc->base.sk);
2503         union sctp_addr addr;
2504         int i;
2505         __u16 sat;
2506         int retval = 1;
2507         sctp_scope_t scope;
2508         u32 stale;
2509         struct sctp_af *af;
2510         union sctp_addr_param *addr_param;
2511         struct sctp_transport *t;
2512         struct sctp_endpoint *ep = asoc->ep;
2513 
2514         /* We maintain all INIT parameters in network byte order all the
2515          * time.  This allows us to not worry about whether the parameters
2516          * came from a fresh INIT, and INIT ACK, or were stored in a cookie.
2517          */
2518         switch (param.p->type) {
2519         case SCTP_PARAM_IPV6_ADDRESS:
2520                 if (PF_INET6 != asoc->base.sk->sk_family)
2521                         break;
2522                 goto do_addr_param;
2523 
2524         case SCTP_PARAM_IPV4_ADDRESS:
2525                 /* v4 addresses are not allowed on v6-only socket */
2526                 if (ipv6_only_sock(asoc->base.sk))
2527                         break;
2528 do_addr_param:
2529                 af = sctp_get_af_specific(param_type2af(param.p->type));
2530                 af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
2531                 scope = sctp_scope(peer_addr);
2532                 if (sctp_in_scope(net, &addr, scope))
2533                         if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
2534                                 return 0;
2535                 break;
2536 
2537         case SCTP_PARAM_COOKIE_PRESERVATIVE:
2538                 if (!net->sctp.cookie_preserve_enable)
2539                         break;
2540 
2541                 stale = ntohl(param.life->lifespan_increment);
2542 
2543                 /* Suggested Cookie Life span increment's unit is msec,
2544                  * (1/1000sec).
2545                  */
2546                 asoc->cookie_life = ktime_add_ms(asoc->cookie_life, stale);
2547                 break;
2548 
2549         case SCTP_PARAM_HOST_NAME_ADDRESS:
2550                 pr_debug("%s: unimplemented SCTP_HOST_NAME_ADDRESS\n", __func__);
2551                 break;
2552 
2553         case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2554                 /* Turn off the default values first so we'll know which
2555                  * ones are really set by the peer.
2556                  */
2557                 asoc->peer.ipv4_address = 0;
2558                 asoc->peer.ipv6_address = 0;
2559 
2560                 /* Assume that peer supports the address family
2561                  * by which it sends a packet.
2562                  */
2563                 if (peer_addr->sa.sa_family == AF_INET6)
2564                         asoc->peer.ipv6_address = 1;
2565                 else if (peer_addr->sa.sa_family == AF_INET)
2566                         asoc->peer.ipv4_address = 1;
2567 
2568                 /* Cycle through address types; avoid divide by 0. */
2569                 sat = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
2570                 if (sat)
2571                         sat /= sizeof(__u16);
2572 
2573                 for (i = 0; i < sat; ++i) {
2574                         switch (param.sat->types[i]) {
2575                         case SCTP_PARAM_IPV4_ADDRESS:
2576                                 asoc->peer.ipv4_address = 1;
2577                                 break;
2578 
2579                         case SCTP_PARAM_IPV6_ADDRESS:
2580                                 if (PF_INET6 == asoc->base.sk->sk_family)
2581                                         asoc->peer.ipv6_address = 1;
2582                                 break;
2583 
2584                         case SCTP_PARAM_HOST_NAME_ADDRESS:
2585                                 asoc->peer.hostname_address = 1;
2586                                 break;
2587 
2588                         default: /* Just ignore anything else.  */
2589                                 break;
2590                         }
2591                 }
2592                 break;
2593 
2594         case SCTP_PARAM_STATE_COOKIE:
2595                 asoc->peer.cookie_len =
2596                         ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
2597                 asoc->peer.cookie = param.cookie->body;
2598                 break;
2599 
2600         case SCTP_PARAM_HEARTBEAT_INFO:
2601                 /* Would be odd to receive, but it causes no problems. */
2602                 break;
2603 
2604         case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2605                 /* Rejected during verify stage. */
2606                 break;
2607 
2608         case SCTP_PARAM_ECN_CAPABLE:
2609                 asoc->peer.ecn_capable = 1;
2610                 break;
2611 
2612         case SCTP_PARAM_ADAPTATION_LAYER_IND:
2613                 asoc->peer.adaptation_ind = ntohl(param.aind->adaptation_ind);
2614                 break;
2615 
2616         case SCTP_PARAM_SET_PRIMARY:
2617                 if (!net->sctp.addip_enable)
2618                         goto fall_through;
2619 
2620                 addr_param = param.v + sizeof(sctp_addip_param_t);
2621 
2622                 af = sctp_get_af_specific(param_type2af(addr_param->p.type));
2623                 if (af == NULL)
2624                         break;
2625 
2626                 af->from_addr_param(&addr, addr_param,
2627                                     htons(asoc->peer.port), 0);
2628 
2629                 /* if the address is invalid, we can't process it.
2630                  * XXX: see spec for what to do.
2631                  */
2632                 if (!af->addr_valid(&addr, NULL, NULL))
2633                         break;
2634 
2635                 t = sctp_assoc_lookup_paddr(asoc, &addr);
2636                 if (!t)
2637                         break;
2638 
2639                 sctp_assoc_set_primary(asoc, t);
2640                 break;
2641 
2642         case SCTP_PARAM_SUPPORTED_EXT:
2643                 sctp_process_ext_param(asoc, param);
2644                 break;
2645 
2646         case SCTP_PARAM_FWD_TSN_SUPPORT:
2647                 if (asoc->prsctp_enable) {
2648                         asoc->peer.prsctp_capable = 1;
2649                         break;
2650                 }
2651                 /* Fall Through */
2652                 goto fall_through;
2653 
2654         case SCTP_PARAM_RANDOM:
2655                 if (!ep->auth_enable)
2656                         goto fall_through;
2657 
2658                 /* Save peer's random parameter */
2659                 asoc->peer.peer_random = kmemdup(param.p,
2660                                             ntohs(param.p->length), gfp);
2661                 if (!asoc->peer.peer_random) {
2662                         retval = 0;
2663                         break;
2664                 }
2665                 break;
2666 
2667         case SCTP_PARAM_HMAC_ALGO:
2668                 if (!ep->auth_enable)
2669                         goto fall_through;
2670 
2671                 /* Save peer's HMAC list */
2672                 asoc->peer.peer_hmacs = kmemdup(param.p,
2673                                             ntohs(param.p->length), gfp);
2674                 if (!asoc->peer.peer_hmacs) {
2675                         retval = 0;
2676                         break;
2677                 }
2678 
2679                 /* Set the default HMAC the peer requested*/
2680                 sctp_auth_asoc_set_default_hmac(asoc, param.hmac_algo);
2681                 break;
2682 
2683         case SCTP_PARAM_CHUNKS:
2684                 if (!ep->auth_enable)
2685                         goto fall_through;
2686 
2687                 asoc->peer.peer_chunks = kmemdup(param.p,
2688                                             ntohs(param.p->length), gfp);
2689                 if (!asoc->peer.peer_chunks)
2690                         retval = 0;
2691                 break;
2692 fall_through:
2693         default:
2694                 /* Any unrecognized parameters should have been caught
2695                  * and handled by sctp_verify_param() which should be
2696                  * called prior to this routine.  Simply log the error
2697                  * here.
2698                  */
2699                 pr_debug("%s: ignoring param:%d for association:%p.\n",
2700                          __func__, ntohs(param.p->type), asoc);
2701                 break;
2702         }
2703 
2704         return retval;
2705 }
2706 
2707 /* Select a new verification tag.  */
2708 __u32 sctp_generate_tag(const struct sctp_endpoint *ep)
2709 {
2710         /* I believe that this random number generator complies with RFC1750.
2711          * A tag of 0 is reserved for special cases (e.g. INIT).
2712          */
2713         __u32 x;
2714 
2715         do {
2716                 get_random_bytes(&x, sizeof(__u32));
2717         } while (x == 0);
2718 
2719         return x;
2720 }
2721 
2722 /* Select an initial TSN to send during startup.  */
2723 __u32 sctp_generate_tsn(const struct sctp_endpoint *ep)
2724 {
2725         __u32 retval;
2726 
2727         get_random_bytes(&retval, sizeof(__u32));
2728         return retval;
2729 }
2730 
2731 /*
2732  * ADDIP 3.1.1 Address Configuration Change Chunk (ASCONF)
2733  *      0                   1                   2                   3
2734  *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
2735  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2736  *     | Type = 0xC1   |  Chunk Flags  |      Chunk Length             |
2737  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2738  *     |                       Serial Number                           |
2739  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2740  *     |                    Address Parameter                          |
2741  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2742  *     |                     ASCONF Parameter #1                       |
2743  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2744  *     \                                                               \
2745  *     /                             ....                              /
2746  *     \                                                               \
2747  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2748  *     |                     ASCONF Parameter #N                       |
2749  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2750  *
2751  * Address Parameter and other parameter will not be wrapped in this function
2752  */
2753 static struct sctp_chunk *sctp_make_asconf(struct sctp_association *asoc,
2754                                            union sctp_addr *addr,
2755                                            int vparam_len)
2756 {
2757         sctp_addiphdr_t asconf;
2758         struct sctp_chunk *retval;
2759         int length = sizeof(asconf) + vparam_len;
2760         union sctp_addr_param addrparam;
2761         int addrlen;
2762         struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
2763 
2764         addrlen = af->to_addr_param(addr, &addrparam);
2765         if (!addrlen)
2766                 return NULL;
2767         length += addrlen;
2768 
2769         /* Create the chunk.  */
2770         retval = sctp_make_control(asoc, SCTP_CID_ASCONF, 0, length,
2771                                    GFP_ATOMIC);
2772         if (!retval)
2773                 return NULL;
2774 
2775         asconf.serial = htonl(asoc->addip_serial++);
2776 
2777         retval->subh.addip_hdr =
2778                 sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2779         retval->param_hdr.v =
2780                 sctp_addto_chunk(retval, addrlen, &addrparam);
2781 
2782         return retval;
2783 }
2784 
2785 /* ADDIP
2786  * 3.2.1 Add IP Address
2787  *      0                   1                   2                   3
2788  *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
2789  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2790  *     |        Type = 0xC001          |    Length = Variable          |
2791  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2792  *     |               ASCONF-Request Correlation ID                   |
2793  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2794  *     |                       Address Parameter                       |
2795  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2796  *
2797  * 3.2.2 Delete IP Address
2798  *      0                   1                   2                   3
2799  *      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
2800  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2801  *     |        Type = 0xC002          |    Length = Variable          |
2802  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2803  *     |               ASCONF-Request Correlation ID                   |
2804  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2805  *     |                       Address Parameter                       |
2806  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2807  *
2808  */
2809 struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *asoc,
2810                                               union sctp_addr         *laddr,
2811                                               struct sockaddr         *addrs,
2812                                               int                     addrcnt,
2813                                               __be16                  flags)
2814 {
2815         sctp_addip_param_t      param;
2816         struct sctp_chunk       *retval;
2817         union sctp_addr_param   addr_param;
2818         union sctp_addr         *addr;
2819         void                    *addr_buf;
2820         struct sctp_af          *af;
2821         int                     paramlen = sizeof(param);
2822         int                     addr_param_len = 0;
2823         int                     totallen = 0;
2824         int                     i;
2825         int                     del_pickup = 0;
2826 
2827         /* Get total length of all the address parameters. */
2828         addr_buf = addrs;
2829         for (i = 0; i < addrcnt; i++) {
2830                 addr = addr_buf;
2831                 af = sctp_get_af_specific(addr->v4.sin_family);
2832                 addr_param_len = af->to_addr_param(addr, &addr_param);
2833 
2834                 totallen += paramlen;
2835                 totallen += addr_param_len;
2836 
2837                 addr_buf += af->sockaddr_len;
2838                 if (asoc->asconf_addr_del_pending && !del_pickup) {
2839                         /* reuse the parameter length from the same scope one */
2840                         totallen += paramlen;
2841                         totallen += addr_param_len;
2842                         del_pickup = 1;
2843 
2844                         pr_debug("%s: picked same-scope del_pending addr, "
2845                                  "totallen for all addresses is %d\n",
2846                                  __func__, totallen);
2847                 }
2848         }
2849 
2850         /* Create an asconf chunk with the required length. */
2851         retval = sctp_make_asconf(asoc, laddr, totallen);
2852         if (!retval)
2853                 return NULL;
2854 
2855         /* Add the address parameters to the asconf chunk. */
2856         addr_buf = addrs;
2857         for (i = 0; i < addrcnt; i++) {
2858                 addr = addr_buf;
2859                 af = sctp_get_af_specific(addr->v4.sin_family);
2860                 addr_param_len = af->to_addr_param(addr, &addr_param);
2861                 param.param_hdr.type = flags;
2862                 param.param_hdr.length = htons(paramlen + addr_param_len);
2863                 param.crr_id = i;
2864 
2865                 sctp_addto_chunk(retval, paramlen, &param);
2866                 sctp_addto_chunk(retval, addr_param_len, &addr_param);
2867 
2868                 addr_buf += af->sockaddr_len;
2869         }
2870         if (flags == SCTP_PARAM_ADD_IP && del_pickup) {
2871                 addr = asoc->asconf_addr_del_pending;
2872                 af = sctp_get_af_specific(addr->v4.sin_family);
2873                 addr_param_len = af->to_addr_param(addr, &addr_param);
2874                 param.param_hdr.type = SCTP_PARAM_DEL_IP;
2875                 param.param_hdr.length = htons(paramlen + addr_param_len);
2876                 param.crr_id = i;
2877 
2878                 sctp_addto_chunk(retval, paramlen, &param);
2879                 sctp_addto_chunk(retval, addr_param_len, &addr_param);
2880         }
2881         return retval;
2882 }
2883 
2884 /* ADDIP
2885  * 3.2.4 Set Primary IP Address
2886  *      0                   1                   2                   3
2887  *      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
2888  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2889  *     |        Type =0xC004           |    Length = Variable          |
2890  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2891  *     |               ASCONF-Request Correlation ID                   |
2892  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2893  *     |                       Address Parameter                       |
2894  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2895  *
2896  * Create an ASCONF chunk with Set Primary IP address parameter.
2897  */
2898 struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
2899                                              union sctp_addr *addr)
2900 {
2901         sctp_addip_param_t      param;
2902         struct sctp_chunk       *retval;
2903         int                     len = sizeof(param);
2904         union sctp_addr_param   addrparam;
2905         int                     addrlen;
2906         struct sctp_af          *af = sctp_get_af_specific(addr->v4.sin_family);
2907 
2908         addrlen = af->to_addr_param(addr, &addrparam);
2909         if (!addrlen)
2910                 return NULL;
2911         len += addrlen;
2912 
2913         /* Create the chunk and make asconf header. */
2914         retval = sctp_make_asconf(asoc, addr, len);
2915         if (!retval)
2916                 return NULL;
2917 
2918         param.param_hdr.type = SCTP_PARAM_SET_PRIMARY;
2919         param.param_hdr.length = htons(len);
2920         param.crr_id = 0;
2921 
2922         sctp_addto_chunk(retval, sizeof(param), &param);
2923         sctp_addto_chunk(retval, addrlen, &addrparam);
2924 
2925         return retval;
2926 }
2927 
2928 /* ADDIP 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
2929  *      0                   1                   2                   3
2930  *      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
2931  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2932  *     | Type = 0x80   |  Chunk Flags  |      Chunk Length             |
2933  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2934  *     |                       Serial Number                           |
2935  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2936  *     |                 ASCONF Parameter Response#1                   |
2937  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2938  *     \                                                               \
2939  *     /                             ....                              /
2940  *     \                                                               \
2941  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2942  *     |                 ASCONF Parameter Response#N                   |
2943  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2944  *
2945  * Create an ASCONF_ACK chunk with enough space for the parameter responses.
2946  */
2947 static struct sctp_chunk *sctp_make_asconf_ack(const struct sctp_association *asoc,
2948                                                __u32 serial, int vparam_len)
2949 {
2950         sctp_addiphdr_t         asconf;
2951         struct sctp_chunk       *retval;
2952         int                     length = sizeof(asconf) + vparam_len;
2953 
2954         /* Create the chunk.  */
2955         retval = sctp_make_control(asoc, SCTP_CID_ASCONF_ACK, 0, length,
2956                                    GFP_ATOMIC);
2957         if (!retval)
2958                 return NULL;
2959 
2960         asconf.serial = htonl(serial);
2961 
2962         retval->subh.addip_hdr =
2963                 sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2964 
2965         return retval;
2966 }
2967 
2968 /* Add response parameters to an ASCONF_ACK chunk. */
2969 static void sctp_add_asconf_response(struct sctp_chunk *chunk, __be32 crr_id,
2970                               __be16 err_code, sctp_addip_param_t *asconf_param)
2971 {
2972         sctp_addip_param_t      ack_param;
2973         sctp_errhdr_t           err_param;
2974         int                     asconf_param_len = 0;
2975         int                     err_param_len = 0;
2976         __be16                  response_type;
2977 
2978         if (SCTP_ERROR_NO_ERROR == err_code) {
2979                 response_type = SCTP_PARAM_SUCCESS_REPORT;
2980         } else {
2981                 response_type = SCTP_PARAM_ERR_CAUSE;
2982                 err_param_len = sizeof(err_param);
2983                 if (asconf_param)
2984                         asconf_param_len =
2985                                  ntohs(asconf_param->param_hdr.length);
2986         }
2987 
2988         /* Add Success Indication or Error Cause Indication parameter. */
2989         ack_param.param_hdr.type = response_type;
2990         ack_param.param_hdr.length = htons(sizeof(ack_param) +
2991                                            err_param_len +
2992                                            asconf_param_len);
2993         ack_param.crr_id = crr_id;
2994         sctp_addto_chunk(chunk, sizeof(ack_param), &ack_param);
2995 
2996         if (SCTP_ERROR_NO_ERROR == err_code)
2997                 return;
2998 
2999         /* Add Error Cause parameter. */
3000         err_param.cause = err_code;
3001         err_param.length = htons(err_param_len + asconf_param_len);
3002         sctp_addto_chunk(chunk, err_param_len, &err_param);
3003 
3004         /* Add the failed TLV copied from ASCONF chunk. */
3005         if (asconf_param)
3006                 sctp_addto_chunk(chunk, asconf_param_len, asconf_param);
3007 }
3008 
3009 /* Process a asconf parameter. */
3010 static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
3011                                        struct sctp_chunk *asconf,
3012                                        sctp_addip_param_t *asconf_param)
3013 {
3014         struct sctp_transport *peer;
3015         struct sctp_af *af;
3016         union sctp_addr addr;
3017         union sctp_addr_param *addr_param;
3018 
3019         addr_param = (void *)asconf_param + sizeof(sctp_addip_param_t);
3020 
3021         if (asconf_param->param_hdr.type != SCTP_PARAM_ADD_IP &&
3022             asconf_param->param_hdr.type != SCTP_PARAM_DEL_IP &&
3023             asconf_param->param_hdr.type != SCTP_PARAM_SET_PRIMARY)
3024                 return SCTP_ERROR_UNKNOWN_PARAM;
3025 
3026         switch (addr_param->p.type) {
3027         case SCTP_PARAM_IPV6_ADDRESS:
3028                 if (!asoc->peer.ipv6_address)
3029                         return SCTP_ERROR_DNS_FAILED;
3030                 break;
3031         case SCTP_PARAM_IPV4_ADDRESS:
3032                 if (!asoc->peer.ipv4_address)
3033                         return SCTP_ERROR_DNS_FAILED;
3034                 break;
3035         default:
3036                 return SCTP_ERROR_DNS_FAILED;
3037         }
3038 
3039         af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3040         if (unlikely(!af))
3041                 return SCTP_ERROR_DNS_FAILED;
3042 
3043         af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);
3044 
3045         /* ADDIP 4.2.1  This parameter MUST NOT contain a broadcast
3046          * or multicast address.
3047          * (note: wildcard is permitted and requires special handling so
3048          *  make sure we check for that)
3049          */
3050         if (!af->is_any(&addr) && !af->addr_valid(&addr, NULL, asconf->skb))
3051                 return SCTP_ERROR_DNS_FAILED;
3052 
3053         switch (asconf_param->param_hdr.type) {
3054         case SCTP_PARAM_ADD_IP:
3055                 /* Section 4.2.1:
3056                  * If the address 0.0.0.0 or ::0 is provided, the source
3057                  * address of the packet MUST be added.
3058                  */
3059                 if (af->is_any(&addr))
3060                         memcpy(&addr, &asconf->source, sizeof(addr));
3061 
3062                 /* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
3063                  * request and does not have the local resources to add this
3064                  * new address to the association, it MUST return an Error
3065                  * Cause TLV set to the new error code 'Operation Refused
3066                  * Due to Resource Shortage'.
3067                  */
3068 
3069                 peer = sctp_assoc_add_peer(asoc, &addr, GFP_ATOMIC, SCTP_UNCONFIRMED);
3070                 if (!peer)
3071                         return SCTP_ERROR_RSRC_LOW;
3072 
3073                 /* Start the heartbeat timer. */
3074                 sctp_transport_reset_hb_timer(peer);
3075                 asoc->new_transport = peer;
3076                 break;
3077         case SCTP_PARAM_DEL_IP:
3078                 /* ADDIP 4.3 D7) If a request is received to delete the
3079                  * last remaining IP address of a peer endpoint, the receiver
3080                  * MUST send an Error Cause TLV with the error cause set to the
3081                  * new error code 'Request to Delete Last Remaining IP Address'.
3082                  */
3083                 if (asoc->peer.transport_count == 1)
3084                         return SCTP_ERROR_DEL_LAST_IP;
3085 
3086                 /* ADDIP 4.3 D8) If a request is received to delete an IP
3087                  * address which is also the source address of the IP packet
3088                  * which contained the ASCONF chunk, the receiver MUST reject
3089                  * this request. To reject the request the receiver MUST send
3090                  * an Error Cause TLV set to the new error code 'Request to
3091                  * Delete Source IP Address'
3092                  */
3093                 if (sctp_cmp_addr_exact(&asconf->source, &addr))
3094                         return SCTP_ERROR_DEL_SRC_IP;
3095 
3096                 /* Section 4.2.2
3097                  * If the address 0.0.0.0 or ::0 is provided, all
3098                  * addresses of the peer except the source address of the
3099                  * packet MUST be deleted.
3100                  */
3101                 if (af->is_any(&addr)) {
3102                         sctp_assoc_set_primary(asoc, asconf->transport);
3103                         sctp_assoc_del_nonprimary_peers(asoc,
3104                                                         asconf->transport);
3105                         return SCTP_ERROR_NO_ERROR;
3106                 }
3107 
3108                 /* If the address is not part of the association, the
3109                  * ASCONF-ACK with Error Cause Indication Parameter
3110                  * which including cause of Unresolvable Address should
3111                  * be sent.
3112                  */
3113                 peer = sctp_assoc_lookup_paddr(asoc, &addr);
3114                 if (!peer)
3115                         return SCTP_ERROR_DNS_FAILED;
3116 
3117                 sctp_assoc_rm_peer(asoc, peer);
3118                 break;
3119         case SCTP_PARAM_SET_PRIMARY:
3120                 /* ADDIP Section 4.2.4
3121                  * If the address 0.0.0.0 or ::0 is provided, the receiver
3122                  * MAY mark the source address of the packet as its
3123                  * primary.
3124                  */
3125                 if (af->is_any(&addr))
3126                         memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));
3127 
3128                 peer = sctp_assoc_lookup_paddr(asoc, &addr);
3129                 if (!peer)
3130                         return SCTP_ERROR_DNS_FAILED;
3131 
3132                 sctp_assoc_set_primary(asoc, peer);
3133                 break;
3134         }
3135 
3136         return SCTP_ERROR_NO_ERROR;
3137 }
3138 
3139 /* Verify the ASCONF packet before we process it. */
3140 bool sctp_verify_asconf(const struct sctp_association *asoc,
3141                         struct sctp_chunk *chunk, bool addr_param_needed,
3142                         struct sctp_paramhdr **errp)
3143 {
3144         sctp_addip_chunk_t *addip = (sctp_addip_chunk_t *) chunk->chunk_hdr;
3145         union sctp_params param;
3146         bool addr_param_seen = false;
3147 
3148         sctp_walk_params(param, addip, addip_hdr.params) {
3149                 size_t length = ntohs(param.p->length);
3150 
3151                 *errp = param.p;
3152                 switch (param.p->type) {
3153                 case SCTP_PARAM_ERR_CAUSE:
3154                         break;
3155                 case SCTP_PARAM_IPV4_ADDRESS:
3156                         if (length != sizeof(sctp_ipv4addr_param_t))
3157                                 return false;
3158                         /* ensure there is only one addr param and it's in the
3159                          * beginning of addip_hdr params, or we reject it.
3160                          */
3161                         if (param.v != addip->addip_hdr.params)
3162                                 return false;
3163                         addr_param_seen = true;
3164                         break;
3165                 case SCTP_PARAM_IPV6_ADDRESS:
3166                         if (length != sizeof(sctp_ipv6addr_param_t))
3167                                 return false;
3168                         if (param.v != addip->addip_hdr.params)
3169                                 return false;
3170                         addr_param_seen = true;
3171                         break;
3172                 case SCTP_PARAM_ADD_IP:
3173                 case SCTP_PARAM_DEL_IP:
3174                 case SCTP_PARAM_SET_PRIMARY:
3175                         /* In ASCONF chunks, these need to be first. */
3176                         if (addr_param_needed && !addr_param_seen)
3177                                 return false;
3178                         length = ntohs(param.addip->param_hdr.length);
3179                         if (length < sizeof(sctp_addip_param_t) +
3180                                      sizeof(**errp))
3181                                 return false;
3182                         break;
3183                 case SCTP_PARAM_SUCCESS_REPORT:
3184                 case SCTP_PARAM_ADAPTATION_LAYER_IND:
3185                         if (length != sizeof(sctp_addip_param_t))
3186                                 return false;
3187                         break;
3188                 default:
3189                         /* This is unkown to us, reject! */
3190                         return false;
3191                 }
3192         }
3193 
3194         /* Remaining sanity checks. */
3195         if (addr_param_needed && !addr_param_seen)
3196                 return false;
3197         if (!addr_param_needed && addr_param_seen)
3198                 return false;
3199         if (param.v != chunk->chunk_end)
3200                 return false;
3201 
3202         return true;
3203 }
3204 
3205 /* Process an incoming ASCONF chunk with the next expected serial no. and
3206  * return an ASCONF_ACK chunk to be sent in response.
3207  */
3208 struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
3209                                        struct sctp_chunk *asconf)
3210 {
3211         sctp_addip_chunk_t *addip = (sctp_addip_chunk_t *) asconf->chunk_hdr;
3212         bool all_param_pass = true;
3213         union sctp_params param;
3214         sctp_addiphdr_t         *hdr;
3215         union sctp_addr_param   *addr_param;
3216         struct sctp_chunk       *asconf_ack;
3217         __be16  err_code;
3218         int     length = 0;
3219         int     chunk_len;
3220         __u32   serial;
3221 
3222         chunk_len = ntohs(asconf->chunk_hdr->length) -
3223                     sizeof(struct sctp_chunkhdr);
3224         hdr = (sctp_addiphdr_t *)asconf->skb->data;
3225         serial = ntohl(hdr->serial);
3226 
3227         /* Skip the addiphdr and store a pointer to address parameter.  */
3228         length = sizeof(sctp_addiphdr_t);
3229         addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3230         chunk_len -= length;
3231 
3232         /* Skip the address parameter and store a pointer to the first
3233          * asconf parameter.
3234          */
3235         length = ntohs(addr_param->p.length);
3236         chunk_len -= length;
3237 
3238         /* create an ASCONF_ACK chunk.
3239          * Based on the definitions of parameters, we know that the size of
3240          * ASCONF_ACK parameters are less than or equal to the fourfold of ASCONF
3241          * parameters.
3242          */
3243         asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 4);
3244         if (!asconf_ack)
3245                 goto done;
3246 
3247         /* Process the TLVs contained within the ASCONF chunk. */
3248         sctp_walk_params(param, addip, addip_hdr.params) {
3249                 /* Skip preceeding address parameters. */
3250                 if (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
3251                     param.p->type == SCTP_PARAM_IPV6_ADDRESS)
3252                         continue;
3253 
3254                 err_code = sctp_process_asconf_param(asoc, asconf,
3255                                                      param.addip);
3256                 /* ADDIP 4.1 A7)
3257                  * If an error response is received for a TLV parameter,
3258                  * all TLVs with no response before the failed TLV are
3259                  * considered successful if not reported.  All TLVs after
3260                  * the failed response are considered unsuccessful unless
3261                  * a specific success indication is present for the parameter.
3262                  */
3263                 if (err_code != SCTP_ERROR_NO_ERROR)
3264                         all_param_pass = false;
3265                 if (!all_param_pass)
3266                         sctp_add_asconf_response(asconf_ack, param.addip->crr_id,
3267                                                  err_code, param.addip);
3268 
3269                 /* ADDIP 4.3 D11) When an endpoint receiving an ASCONF to add
3270                  * an IP address sends an 'Out of Resource' in its response, it
3271                  * MUST also fail any subsequent add or delete requests bundled
3272                  * in the ASCONF.
3273                  */
3274                 if (err_code == SCTP_ERROR_RSRC_LOW)
3275                         goto done;
3276         }
3277 done:
3278         asoc->peer.addip_serial++;
3279 
3280         /* If we are sending a new ASCONF_ACK hold a reference to it in assoc
3281          * after freeing the reference to old asconf ack if any.
3282          */
3283         if (asconf_ack) {
3284                 sctp_chunk_hold(asconf_ack);
3285                 list_add_tail(&asconf_ack->transmitted_list,
3286                               &asoc->asconf_ack_list);
3287         }
3288 
3289         return asconf_ack;
3290 }
3291 
3292 /* Process a asconf parameter that is successfully acked. */
3293 static void sctp_asconf_param_success(struct sctp_association *asoc,
3294                                      sctp_addip_param_t *asconf_param)
3295 {
3296         struct sctp_af *af;
3297         union sctp_addr addr;
3298         struct sctp_bind_addr *bp = &asoc->base.bind_addr;
3299         union sctp_addr_param *addr_param;
3300         struct sctp_transport *transport;
3301         struct sctp_sockaddr_entry *saddr;
3302 
3303         addr_param = (void *)asconf_param + sizeof(sctp_addip_param_t);
3304 
3305         /* We have checked the packet before, so we do not check again. */
3306         af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3307         af->from_addr_param(&addr, addr_param, htons(bp->port), 0);
3308 
3309         switch (asconf_param->param_hdr.type) {
3310         case SCTP_PARAM_ADD_IP:
3311                 /* This is always done in BH context with a socket lock
3312                  * held, so the list can not change.
3313                  */
3314                 local_bh_disable();
3315                 list_for_each_entry(saddr, &bp->address_list, list) {
3316                         if (sctp_cmp_addr_exact(&saddr->a, &addr))
3317                                 saddr->state = SCTP_ADDR_SRC;
3318                 }
3319                 local_bh_enable();
3320                 list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3321                                 transports) {
3322                         sctp_transport_dst_release(transport);
3323                 }
3324                 break;
3325         case SCTP_PARAM_DEL_IP:
3326                 local_bh_disable();
3327                 sctp_del_bind_addr(bp, &addr);
3328                 if (asoc->asconf_addr_del_pending != NULL &&
3329                     sctp_cmp_addr_exact(asoc->asconf_addr_del_pending, &addr)) {
3330                         kfree(asoc->asconf_addr_del_pending);
3331                         asoc->asconf_addr_del_pending = NULL;
3332                 }
3333                 local_bh_enable();
3334                 list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3335                                 transports) {
3336                         sctp_transport_dst_release(transport);
3337                 }
3338                 break;
3339         default:
3340                 break;
3341         }
3342 }
3343 
3344 /* Get the corresponding ASCONF response error code from the ASCONF_ACK chunk
3345  * for the given asconf parameter.  If there is no response for this parameter,
3346  * return the error code based on the third argument 'no_err'.
3347  * ADDIP 4.1
3348  * A7) If an error response is received for a TLV parameter, all TLVs with no
3349  * response before the failed TLV are considered successful if not reported.
3350  * All TLVs after the failed response are considered unsuccessful unless a
3351  * specific success indication is present for the parameter.
3352  */
3353 static __be16 sctp_get_asconf_response(struct sctp_chunk *asconf_ack,
3354                                       sctp_addip_param_t *asconf_param,
3355                                       int no_err)
3356 {
3357         sctp_addip_param_t      *asconf_ack_param;
3358         sctp_errhdr_t           *err_param;
3359         int                     length;
3360         int                     asconf_ack_len;
3361         __be16                  err_code;
3362 
3363         if (no_err)
3364                 err_code = SCTP_ERROR_NO_ERROR;
3365         else
3366                 err_code = SCTP_ERROR_REQ_REFUSED;
3367 
3368         asconf_ack_len = ntohs(asconf_ack->chunk_hdr->length) -
3369                          sizeof(struct sctp_chunkhdr);
3370 
3371         /* Skip the addiphdr from the asconf_ack chunk and store a pointer to
3372          * the first asconf_ack parameter.
3373          */
3374         length = sizeof(sctp_addiphdr_t);
3375         asconf_ack_param = (sctp_addip_param_t *)(asconf_ack->skb->data +
3376                                                   length);
3377         asconf_ack_len -= length;
3378 
3379         while (asconf_ack_len > 0) {
3380                 if (asconf_ack_param->crr_id == asconf_param->crr_id) {
3381                         switch (asconf_ack_param->param_hdr.type) {
3382                         case SCTP_PARAM_SUCCESS_REPORT:
3383                                 return SCTP_ERROR_NO_ERROR;
3384                         case SCTP_PARAM_ERR_CAUSE:
3385                                 length = sizeof(sctp_addip_param_t);
3386                                 err_param = (void *)asconf_ack_param + length;
3387                                 asconf_ack_len -= length;
3388                                 if (asconf_ack_len > 0)
3389                                         return err_param->cause;
3390                                 else
3391                                         return SCTP_ERROR_INV_PARAM;
3392                                 break;
3393                         default:
3394                                 return SCTP_ERROR_INV_PARAM;
3395                         }
3396                 }
3397 
3398                 length = ntohs(asconf_ack_param->param_hdr.length);
3399                 asconf_ack_param = (void *)asconf_ack_param + length;
3400                 asconf_ack_len -= length;
3401         }
3402 
3403         return err_code;
3404 }
3405 
3406 /* Process an incoming ASCONF_ACK chunk against the cached last ASCONF chunk. */
3407 int sctp_process_asconf_ack(struct sctp_association *asoc,
3408                             struct sctp_chunk *asconf_ack)
3409 {
3410         struct sctp_chunk       *asconf = asoc->addip_last_asconf;
3411         union sctp_addr_param   *addr_param;
3412         sctp_addip_param_t      *asconf_param;
3413         int     length = 0;
3414         int     asconf_len = asconf->skb->len;
3415         int     all_param_pass = 0;
3416         int     no_err = 1;
3417         int     retval = 0;
3418         __be16  err_code = SCTP_ERROR_NO_ERROR;
3419 
3420         /* Skip the chunkhdr and addiphdr from the last asconf sent and store
3421          * a pointer to address parameter.
3422          */
3423         length = sizeof(sctp_addip_chunk_t);
3424         addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3425         asconf_len -= length;
3426 
3427         /* Skip the address parameter in the last asconf sent and store a
3428          * pointer to the first asconf parameter.
3429          */
3430         length = ntohs(addr_param->p.length);
3431         asconf_param = (void *)addr_param + length;
3432         asconf_len -= length;
3433 
3434         /* ADDIP 4.1
3435          * A8) If there is no response(s) to specific TLV parameter(s), and no
3436          * failures are indicated, then all request(s) are considered
3437          * successful.
3438          */
3439         if (asconf_ack->skb->len == sizeof(sctp_addiphdr_t))
3440                 all_param_pass = 1;
3441 
3442         /* Process the TLVs contained in the last sent ASCONF chunk. */
3443         while (asconf_len > 0) {
3444                 if (all_param_pass)
3445                         err_code = SCTP_ERROR_NO_ERROR;
3446                 else {
3447                         err_code = sctp_get_asconf_response(asconf_ack,
3448                                                             asconf_param,
3449                                                             no_err);
3450                         if (no_err && (SCTP_ERROR_NO_ERROR != err_code))
3451                                 no_err = 0;
3452                 }
3453 
3454                 switch (err_code) {
3455                 case SCTP_ERROR_NO_ERROR:
3456                         sctp_asconf_param_success(asoc, asconf_param);
3457                         break;
3458 
3459                 case SCTP_ERROR_RSRC_LOW:
3460                         retval = 1;
3461                         break;
3462 
3463                 case SCTP_ERROR_UNKNOWN_PARAM:
3464                         /* Disable sending this type of asconf parameter in
3465                          * future.
3466                          */
3467                         asoc->peer.addip_disabled_mask |=
3468                                 asconf_param->param_hdr.type;
3469                         break;
3470 
3471                 case SCTP_ERROR_REQ_REFUSED:
3472                 case SCTP_ERROR_DEL_LAST_IP:
3473                 case SCTP_ERROR_DEL_SRC_IP:
3474                 default:
3475                          break;
3476                 }
3477 
3478                 /* Skip the processed asconf parameter and move to the next
3479                  * one.
3480                  */
3481                 length = ntohs(asconf_param->param_hdr.length);
3482                 asconf_param = (void *)asconf_param + length;
3483                 asconf_len -= length;
3484         }
3485 
3486         if (no_err && asoc->src_out_of_asoc_ok) {
3487                 asoc->src_out_of_asoc_ok = 0;
3488                 sctp_transport_immediate_rtx(asoc->peer.primary_path);
3489         }
3490 
3491         /* Free the cached last sent asconf chunk. */
3492         list_del_init(&asconf->transmitted_list);
3493         sctp_chunk_free(asconf);
3494         asoc->addip_last_asconf = NULL;
3495 
3496         return retval;
3497 }
3498 
3499 /* Make a FWD TSN chunk. */
3500 struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
3501                                     __u32 new_cum_tsn, size_t nstreams,
3502                                     struct sctp_fwdtsn_skip *skiplist)
3503 {
3504         struct sctp_chunk *retval = NULL;
3505         struct sctp_fwdtsn_hdr ftsn_hdr;
3506         struct sctp_fwdtsn_skip skip;
3507         size_t hint;
3508         int i;
3509 
3510         hint = (nstreams + 1) * sizeof(__u32);
3511 
3512         retval = sctp_make_control(asoc, SCTP_CID_FWD_TSN, 0, hint, GFP_ATOMIC);
3513 
3514         if (!retval)
3515                 return NULL;
3516 
3517         ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
3518         retval->subh.fwdtsn_hdr =
3519                 sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
3520 
3521         for (i = 0; i < nstreams; i++) {
3522                 skip.stream = skiplist[i].stream;
3523                 skip.ssn = skiplist[i].ssn;
3524                 sctp_addto_chunk(retval, sizeof(skip), &skip);
3525         }
3526 
3527         return retval;
3528 }
3529 
3530 /* RE-CONFIG 3.1 (RE-CONFIG chunk)
3531  *   0                   1                   2                   3
3532  *   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
3533  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3534  *  | Type = 130    |  Chunk Flags  |      Chunk Length             |
3535  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3536  *  \                                                               \
3537  *  /                  Re-configuration Parameter                   /
3538  *  \                                                               \
3539  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3540  *  \                                                               \
3541  *  /             Re-configuration Parameter (optional)             /
3542  *  \                                                               \
3543  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3544  */
3545 static struct sctp_chunk *sctp_make_reconf(
3546                                 const struct sctp_association *asoc,
3547                                 int length)
3548 {
3549         struct sctp_reconf_chunk *reconf;
3550         struct sctp_chunk *retval;
3551 
3552         retval = sctp_make_control(asoc, SCTP_CID_RECONF, 0, length,
3553                                    GFP_ATOMIC);
3554         if (!retval)
3555                 return NULL;
3556 
3557         reconf = (struct sctp_reconf_chunk *)retval->chunk_hdr;
3558         retval->param_hdr.v = reconf->params;
3559 
3560         return retval;
3561 }
3562 
3563 /* RE-CONFIG 4.1 (STREAM OUT RESET)
3564  *   0                   1                   2                   3
3565  *   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
3566  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3567  *  |     Parameter Type = 13       | Parameter Length = 16 + 2 * N |
3568  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3569  *  |           Re-configuration Request Sequence Number            |
3570  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3571  *  |           Re-configuration Response Sequence Number           |
3572  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3573  *  |                Sender's Last Assigned TSN                     |
3574  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3575  *  |  Stream Number 1 (optional)   |    Stream Number 2 (optional) |
3576  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3577  *  /                            ......                             /
3578  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3579  *  |  Stream Number N-1 (optional) |    Stream Number N (optional) |
3580  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3581  *
3582  * RE-CONFIG 4.2 (STREAM IN RESET)
3583  *   0                   1                   2                   3
3584  *   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
3585  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3586  *  |     Parameter Type = 14       |  Parameter Length = 8 + 2 * N |
3587  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3588  *  |          Re-configuration Request Sequence Number             |
3589  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3590  *  |  Stream Number 1 (optional)   |    Stream Number 2 (optional) |
3591  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3592  *  /                            ......                             /
3593  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3594  *  |  Stream Number N-1 (optional) |    Stream Number N (optional) |
3595  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3596  */
3597 struct sctp_chunk *sctp_make_strreset_req(
3598                                 const struct sctp_association *asoc,
3599                                 __u16 stream_num, __u16 *stream_list,
3600                                 bool out, bool in)
3601 {
3602         struct sctp_strreset_outreq outreq;
3603         __u16 stream_len = stream_num * 2;
3604         struct sctp_strreset_inreq inreq;
3605         struct sctp_chunk *retval;
3606         __u16 outlen, inlen;
3607 
3608         outlen = (sizeof(outreq) + stream_len) * out;
3609         inlen = (sizeof(inreq) + stream_len) * in;
3610 
3611         retval = sctp_make_reconf(asoc, outlen + inlen);
3612         if (!retval)
3613                 return NULL;
3614 
3615         if (outlen) {
3616                 outreq.param_hdr.type = SCTP_PARAM_RESET_OUT_REQUEST;
3617                 outreq.param_hdr.length = htons(outlen);
3618                 outreq.request_seq = htonl(asoc->strreset_outseq);
3619                 outreq.response_seq = htonl(asoc->strreset_inseq - 1);
3620                 outreq.send_reset_at_tsn = htonl(asoc->next_tsn - 1);
3621 
3622                 sctp_addto_chunk(retval, sizeof(outreq), &outreq);
3623 
3624                 if (stream_len)
3625                         sctp_addto_chunk(retval, stream_len, stream_list);
3626         }
3627 
3628         if (inlen) {
3629                 inreq.param_hdr.type = SCTP_PARAM_RESET_IN_REQUEST;
3630                 inreq.param_hdr.length = htons(inlen);
3631                 inreq.request_seq = htonl(asoc->strreset_outseq + out);
3632 
3633                 sctp_addto_chunk(retval, sizeof(inreq), &inreq);
3634 
3635                 if (stream_len)
3636                         sctp_addto_chunk(retval, stream_len, stream_list);
3637         }
3638 
3639         return retval;
3640 }
3641 
3642 /* RE-CONFIG 4.3 (SSN/TSN RESET ALL)
3643  *   0                   1                   2                   3
3644  *   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
3645  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3646  *  |     Parameter Type = 15       |      Parameter Length = 8     |
3647  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3648  *  |         Re-configuration Request Sequence Number              |
3649  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3650  */
3651 struct sctp_chunk *sctp_make_strreset_tsnreq(
3652                                 const struct sctp_association *asoc)
3653 {
3654         struct sctp_strreset_tsnreq tsnreq;
3655         __u16 length = sizeof(tsnreq);
3656         struct sctp_chunk *retval;
3657 
3658         retval = sctp_make_reconf(asoc, length);
3659         if (!retval)
3660                 return NULL;
3661 
3662         tsnreq.param_hdr.type = SCTP_PARAM_RESET_TSN_REQUEST;
3663         tsnreq.param_hdr.length = htons(length);
3664         tsnreq.request_seq = htonl(asoc->strreset_outseq);
3665 
3666         sctp_addto_chunk(retval, sizeof(tsnreq), &tsnreq);
3667 
3668         return retval;
3669 }
3670 
3671 /* RE-CONFIG 4.5/4.6 (ADD STREAM)
3672  *   0                   1                   2                   3
3673  *   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
3674  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3675  *  |     Parameter Type = 17       |      Parameter Length = 12    |
3676  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3677  *  |          Re-configuration Request Sequence Number             |
3678  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3679  *  |      Number of new streams    |         Reserved              |
3680  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3681  */
3682 struct sctp_chunk *sctp_make_strreset_addstrm(
3683                                 const struct sctp_association *asoc,
3684                                 __u16 out, __u16 in)
3685 {
3686         struct sctp_strreset_addstrm addstrm;
3687         __u16 size = sizeof(addstrm);
3688         struct sctp_chunk *retval;
3689 
3690         retval = sctp_make_reconf(asoc, (!!out + !!in) * size);
3691         if (!retval)
3692                 return NULL;
3693 
3694         if (out) {
3695                 addstrm.param_hdr.type = SCTP_PARAM_RESET_ADD_OUT_STREAMS;
3696                 addstrm.param_hdr.length = htons(size);
3697                 addstrm.number_of_streams = htons(out);
3698                 addstrm.request_seq = htonl(asoc->strreset_outseq);
3699                 addstrm.reserved = 0;
3700 
3701                 sctp_addto_chunk(retval, size, &addstrm);
3702         }
3703 
3704         if (in) {
3705                 addstrm.param_hdr.type = SCTP_PARAM_RESET_ADD_IN_STREAMS;
3706                 addstrm.param_hdr.length = htons(size);
3707                 addstrm.number_of_streams = htons(in);
3708                 addstrm.request_seq = htonl(asoc->strreset_outseq + !!out);
3709                 addstrm.reserved = 0;
3710 
3711                 sctp_addto_chunk(retval, size, &addstrm);
3712         }
3713 
3714         return retval;
3715 }
3716 
3717 /* RE-CONFIG 4.4 (RESP)
3718  *   0                   1                   2                   3
3719  *   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
3720  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3721  *  |     Parameter Type = 16       |      Parameter Length         |
3722  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3723  *  |         Re-configuration Response Sequence Number             |
3724  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3725  *  |                            Result                             |
3726  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3727  */
3728 struct sctp_chunk *sctp_make_strreset_resp(
3729                                 const struct sctp_association *asoc,
3730                                 __u32 result, __u32 sn)
3731 {
3732         struct sctp_strreset_resp resp;
3733         __u16 length = sizeof(resp);
3734         struct sctp_chunk *retval;
3735 
3736         retval = sctp_make_reconf(asoc, length);
3737         if (!retval)
3738                 return NULL;
3739 
3740         resp.param_hdr.type = SCTP_PARAM_RESET_RESPONSE;
3741         resp.param_hdr.length = htons(length);
3742         resp.response_seq = htonl(sn);
3743         resp.result = htonl(result);
3744 
3745         sctp_addto_chunk(retval, sizeof(resp), &resp);
3746 
3747         return retval;
3748 }
3749 
3750 /* RE-CONFIG 4.4 OPTIONAL (TSNRESP)
3751  *   0                   1                   2                   3
3752  *   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
3753  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3754  *  |     Parameter Type = 16       |      Parameter Length         |
3755  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3756  *  |         Re-configuration Response Sequence Number             |
3757  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3758  *  |                            Result                             |
3759  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3760  *  |                   Sender's Next TSN (optional)                |
3761  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3762  *  |                  Receiver's Next TSN (optional)               |
3763  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3764  */
3765 struct sctp_chunk *sctp_make_strreset_tsnresp(
3766                                         struct sctp_association *asoc,
3767                                         __u32 result, __u32 sn,
3768                                         __u32 sender_tsn, __u32 receiver_tsn)
3769 {
3770         struct sctp_strreset_resptsn tsnresp;
3771         __u16 length = sizeof(tsnresp);
3772         struct sctp_chunk *retval;
3773 
3774         retval = sctp_make_reconf(asoc, length);
3775         if (!retval)
3776                 return NULL;
3777 
3778         tsnresp.param_hdr.type = SCTP_PARAM_RESET_RESPONSE;
3779         tsnresp.param_hdr.length = htons(length);
3780 
3781         tsnresp.response_seq = htonl(sn);
3782         tsnresp.result = htonl(result);
3783         tsnresp.senders_next_tsn = htonl(sender_tsn);
3784         tsnresp.receivers_next_tsn = htonl(receiver_tsn);
3785 
3786         sctp_addto_chunk(retval, sizeof(tsnresp), &tsnresp);
3787 
3788         return retval;
3789 }
3790 
3791 bool sctp_verify_reconf(const struct sctp_association *asoc,
3792                         struct sctp_chunk *chunk,
3793                         struct sctp_paramhdr **errp)
3794 {
3795         struct sctp_reconf_chunk *hdr;
3796         union sctp_params param;
3797         __u16 last = 0, cnt = 0;
3798 
3799         hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
3800         sctp_walk_params(param, hdr, params) {
3801                 __u16 length = ntohs(param.p->length);
3802 
3803                 *errp = param.p;
3804                 if (cnt++ > 2)
3805                         return false;
3806                 switch (param.p->type) {
3807                 case SCTP_PARAM_RESET_OUT_REQUEST:
3808                         if (length < sizeof(struct sctp_strreset_outreq) ||
3809                             (last && last != SCTP_PARAM_RESET_RESPONSE &&
3810                              last != SCTP_PARAM_RESET_IN_REQUEST))
3811                                 return false;
3812                         break;
3813                 case SCTP_PARAM_RESET_IN_REQUEST:
3814                         if (length < sizeof(struct sctp_strreset_inreq) ||
3815                             (last && last != SCTP_PARAM_RESET_OUT_REQUEST))
3816                                 return false;
3817                         break;
3818                 case SCTP_PARAM_RESET_RESPONSE:
3819                         if ((length != sizeof(struct sctp_strreset_resp) &&
3820                              length != sizeof(struct sctp_strreset_resptsn)) ||
3821                             (last && last != SCTP_PARAM_RESET_RESPONSE &&
3822                              last != SCTP_PARAM_RESET_OUT_REQUEST))
3823                                 return false;
3824                         break;
3825                 case SCTP_PARAM_RESET_TSN_REQUEST:
3826                         if (length !=
3827                             sizeof(struct sctp_strreset_tsnreq) || last)
3828                                 return false;
3829                         break;
3830                 case SCTP_PARAM_RESET_ADD_IN_STREAMS:
3831                         if (length != sizeof(struct sctp_strreset_addstrm) ||
3832                             (last && last != SCTP_PARAM_RESET_ADD_OUT_STREAMS))
3833                                 return false;
3834                         break;
3835                 case SCTP_PARAM_RESET_ADD_OUT_STREAMS:
3836                         if (length != sizeof(struct sctp_strreset_addstrm) ||
3837                             (last && last != SCTP_PARAM_RESET_ADD_IN_STREAMS))
3838                                 return false;
3839                         break;
3840                 default:
3841                         return false;
3842                 }
3843 
3844                 last = param.p->type;
3845         }
3846 
3847         return true;
3848 }
3849 

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