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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 sctp_af *af;
112         int iif = 0;
113 
114         af = sctp_get_af_specific(ipver2af(ip_hdr(chunk->skb)->version));
115         if (af)
116                 iif = af->skb_iif(chunk->skb);
117 
118         return iif;
119 }
120 
121 /* RFC 2960 3.3.2 Initiation (INIT) (1)
122  *
123  * Note 2: The ECN capable field is reserved for future use of
124  * Explicit Congestion Notification.
125  */
126 static const struct sctp_paramhdr ecap_param = {
127         SCTP_PARAM_ECN_CAPABLE,
128         cpu_to_be16(sizeof(struct sctp_paramhdr)),
129 };
130 static const struct sctp_paramhdr prsctp_param = {
131         SCTP_PARAM_FWD_TSN_SUPPORT,
132         cpu_to_be16(sizeof(struct sctp_paramhdr)),
133 };
134 
135 /* A helper to initialize an op error inside a
136  * provided chunk, as most cause codes will be embedded inside an
137  * abort chunk.
138  */
139 void  sctp_init_cause(struct sctp_chunk *chunk, __be16 cause_code,
140                       size_t paylen)
141 {
142         sctp_errhdr_t err;
143         __u16 len;
144 
145         /* Cause code constants are now defined in network order.  */
146         err.cause = cause_code;
147         len = sizeof(sctp_errhdr_t) + paylen;
148         err.length  = htons(len);
149         chunk->subh.err_hdr = sctp_addto_chunk(chunk, sizeof(sctp_errhdr_t), &err);
150 }
151 
152 /* A helper to initialize an op error inside a
153  * provided chunk, as most cause codes will be embedded inside an
154  * abort chunk.  Differs from sctp_init_cause in that it won't oops
155  * if there isn't enough space in the op error chunk
156  */
157 static int sctp_init_cause_fixed(struct sctp_chunk *chunk, __be16 cause_code,
158                       size_t paylen)
159 {
160         sctp_errhdr_t err;
161         __u16 len;
162 
163         /* Cause code constants are now defined in network order.  */
164         err.cause = cause_code;
165         len = sizeof(sctp_errhdr_t) + paylen;
166         err.length  = htons(len);
167 
168         if (skb_tailroom(chunk->skb) < len)
169                 return -ENOSPC;
170         chunk->subh.err_hdr = sctp_addto_chunk_fixed(chunk,
171                                                      sizeof(sctp_errhdr_t),
172                                                      &err);
173         return 0;
174 }
175 /* 3.3.2 Initiation (INIT) (1)
176  *
177  * This chunk is used to initiate a SCTP association between two
178  * endpoints. The format of the INIT chunk is shown below:
179  *
180  *     0                   1                   2                   3
181  *     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
182  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
183  *    |   Type = 1    |  Chunk Flags  |      Chunk Length             |
184  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
185  *    |                         Initiate Tag                          |
186  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
187  *    |           Advertised Receiver Window Credit (a_rwnd)          |
188  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
189  *    |  Number of Outbound Streams   |  Number of Inbound Streams    |
190  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
191  *    |                          Initial TSN                          |
192  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
193  *    \                                                               \
194  *    /              Optional/Variable-Length Parameters              /
195  *    \                                                               \
196  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
197  *
198  *
199  * The INIT chunk contains the following parameters. Unless otherwise
200  * noted, each parameter MUST only be included once in the INIT chunk.
201  *
202  * Fixed Parameters                     Status
203  * ----------------------------------------------
204  * Initiate Tag                        Mandatory
205  * Advertised Receiver Window Credit   Mandatory
206  * Number of Outbound Streams          Mandatory
207  * Number of Inbound Streams           Mandatory
208  * Initial TSN                         Mandatory
209  *
210  * Variable Parameters                  Status     Type Value
211  * -------------------------------------------------------------
212  * IPv4 Address (Note 1)               Optional    5
213  * IPv6 Address (Note 1)               Optional    6
214  * Cookie Preservative                 Optional    9
215  * Reserved for ECN Capable (Note 2)   Optional    32768 (0x8000)
216  * Host Name Address (Note 3)          Optional    11
217  * Supported Address Types (Note 4)    Optional    12
218  */
219 struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc,
220                              const struct sctp_bind_addr *bp,
221                              gfp_t gfp, int vparam_len)
222 {
223         struct net *net = sock_net(asoc->base.sk);
224         struct sctp_endpoint *ep = asoc->ep;
225         sctp_inithdr_t init;
226         union sctp_params addrs;
227         size_t chunksize;
228         struct sctp_chunk *retval = NULL;
229         int num_types, addrs_len = 0;
230         struct sctp_sock *sp;
231         sctp_supported_addrs_param_t sat;
232         __be16 types[2];
233         sctp_adaptation_ind_param_t aiparam;
234         sctp_supported_ext_param_t ext_param;
235         int num_ext = 0;
236         __u8 extensions[3];
237         sctp_paramhdr_t *auth_chunks = NULL,
238                         *auth_hmacs = NULL;
239 
240         /* RFC 2960 3.3.2 Initiation (INIT) (1)
241          *
242          * Note 1: The INIT chunks can contain multiple addresses that
243          * can be IPv4 and/or IPv6 in any combination.
244          */
245         retval = NULL;
246 
247         /* Convert the provided bind address list to raw format. */
248         addrs = sctp_bind_addrs_to_raw(bp, &addrs_len, gfp);
249 
250         init.init_tag              = htonl(asoc->c.my_vtag);
251         init.a_rwnd                = htonl(asoc->rwnd);
252         init.num_outbound_streams  = htons(asoc->c.sinit_num_ostreams);
253         init.num_inbound_streams   = htons(asoc->c.sinit_max_instreams);
254         init.initial_tsn           = htonl(asoc->c.initial_tsn);
255 
256         /* How many address types are needed? */
257         sp = sctp_sk(asoc->base.sk);
258         num_types = sp->pf->supported_addrs(sp, types);
259 
260         chunksize = sizeof(init) + addrs_len;
261         chunksize += WORD_ROUND(SCTP_SAT_LEN(num_types));
262         chunksize += sizeof(ecap_param);
263 
264         if (net->sctp.prsctp_enable)
265                 chunksize += sizeof(prsctp_param);
266 
267         /* ADDIP: Section 4.2.7:
268          *  An implementation supporting this extension [ADDIP] MUST list
269          *  the ASCONF,the ASCONF-ACK, and the AUTH  chunks in its INIT and
270          *  INIT-ACK parameters.
271          */
272         if (net->sctp.addip_enable) {
273                 extensions[num_ext] = SCTP_CID_ASCONF;
274                 extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
275                 num_ext += 2;
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 = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
290                 if (auth_hmacs->length)
291                         chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
292                 else
293                         auth_hmacs = NULL;
294 
295                 /* Add CHUNKS parameter length */
296                 auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
297                 if (auth_chunks->length)
298                         chunksize += WORD_ROUND(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 += WORD_ROUND(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 (net->sctp.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         sctp_inithdr_t 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[3];
400         sctp_paramhdr_t *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 (sp->adaptation_ind)
443                 chunksize += sizeof(aiparam);
444 
445         if (asoc->peer.auth_capable) {
446                 auth_random = (sctp_paramhdr_t *)asoc->c.auth_random;
447                 chunksize += ntohs(auth_random->length);
448 
449                 auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
450                 if (auth_hmacs->length)
451                         chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
452                 else
453                         auth_hmacs = NULL;
454 
455                 auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
456                 if (auth_chunks->length)
457                         chunksize += WORD_ROUND(ntohs(auth_chunks->length));
458                 else
459                         auth_chunks = NULL;
460 
461                 extensions[num_ext] = SCTP_CID_AUTH;
462                 num_ext += 1;
463         }
464 
465         if (num_ext)
466                 chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) +
467                                         num_ext);
468 
469         /* Now allocate and fill out the chunk.  */
470         retval = sctp_make_control(asoc, SCTP_CID_INIT_ACK, 0, chunksize, gfp);
471         if (!retval)
472                 goto nomem_chunk;
473 
474         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
475          *
476          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
477          * HEARTBEAT ACK, * etc.) to the same destination transport
478          * address from which it received the DATA or control chunk
479          * to which it is replying.
480          *
481          * [INIT ACK back to where the INIT came from.]
482          */
483         retval->transport = chunk->transport;
484 
485         retval->subh.init_hdr =
486                 sctp_addto_chunk(retval, sizeof(initack), &initack);
487         retval->param_hdr.v = sctp_addto_chunk(retval, addrs_len, addrs.v);
488         sctp_addto_chunk(retval, cookie_len, cookie);
489         if (asoc->peer.ecn_capable)
490                 sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
491         if (num_ext) {
492                 ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
493                 ext_param.param_hdr.length =
494                             htons(sizeof(sctp_supported_ext_param_t) + num_ext);
495                 sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
496                                  &ext_param);
497                 sctp_addto_param(retval, num_ext, extensions);
498         }
499         if (asoc->peer.prsctp_capable)
500                 sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
501 
502         if (sp->adaptation_ind) {
503                 aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
504                 aiparam.param_hdr.length = htons(sizeof(aiparam));
505                 aiparam.adaptation_ind = htonl(sp->adaptation_ind);
506                 sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
507         }
508 
509         if (asoc->peer.auth_capable) {
510                 sctp_addto_chunk(retval, ntohs(auth_random->length),
511                                  auth_random);
512                 if (auth_hmacs)
513                         sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
514                                         auth_hmacs);
515                 if (auth_chunks)
516                         sctp_addto_chunk(retval, ntohs(auth_chunks->length),
517                                         auth_chunks);
518         }
519 
520         /* We need to remove the const qualifier at this point.  */
521         retval->asoc = (struct sctp_association *) asoc;
522 
523 nomem_chunk:
524         kfree(cookie);
525 nomem_cookie:
526         kfree(addrs.v);
527         return retval;
528 }
529 
530 /* 3.3.11 Cookie Echo (COOKIE ECHO) (10):
531  *
532  * This chunk is used only during the initialization of an association.
533  * It is sent by the initiator of an association to its peer to complete
534  * the initialization process. This chunk MUST precede any DATA chunk
535  * sent within the association, but MAY be bundled with one or more DATA
536  * chunks in the same packet.
537  *
538  *      0                   1                   2                   3
539  *      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
540  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
541  *     |   Type = 10   |Chunk  Flags   |         Length                |
542  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
543  *     /                     Cookie                                    /
544  *     \                                                               \
545  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
546  *
547  * Chunk Flags: 8 bit
548  *
549  *   Set to zero on transmit and ignored on receipt.
550  *
551  * Length: 16 bits (unsigned integer)
552  *
553  *   Set to the size of the chunk in bytes, including the 4 bytes of
554  *   the chunk header and the size of the Cookie.
555  *
556  * Cookie: variable size
557  *
558  *   This field must contain the exact cookie received in the
559  *   State Cookie parameter from the previous INIT ACK.
560  *
561  *   An implementation SHOULD make the cookie as small as possible
562  *   to insure interoperability.
563  */
564 struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *asoc,
565                                     const struct sctp_chunk *chunk)
566 {
567         struct sctp_chunk *retval;
568         void *cookie;
569         int cookie_len;
570 
571         cookie = asoc->peer.cookie;
572         cookie_len = asoc->peer.cookie_len;
573 
574         /* Build a cookie echo chunk.  */
575         retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ECHO, 0,
576                                    cookie_len, GFP_ATOMIC);
577         if (!retval)
578                 goto nodata;
579         retval->subh.cookie_hdr =
580                 sctp_addto_chunk(retval, cookie_len, cookie);
581 
582         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
583          *
584          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
585          * HEARTBEAT ACK, * etc.) to the same destination transport
586          * address from which it * received the DATA or control chunk
587          * to which it is replying.
588          *
589          * [COOKIE ECHO back to where the INIT ACK came from.]
590          */
591         if (chunk)
592                 retval->transport = chunk->transport;
593 
594 nodata:
595         return retval;
596 }
597 
598 /* 3.3.12 Cookie Acknowledgement (COOKIE ACK) (11):
599  *
600  * This chunk is used only during the initialization of an
601  * association.  It is used to acknowledge the receipt of a COOKIE
602  * ECHO chunk.  This chunk MUST precede any DATA or SACK chunk sent
603  * within the association, but MAY be bundled with one or more DATA
604  * chunks or SACK chunk in the same SCTP packet.
605  *
606  *      0                   1                   2                   3
607  *      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
608  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
609  *     |   Type = 11   |Chunk  Flags   |     Length = 4                |
610  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
611  *
612  * Chunk Flags: 8 bits
613  *
614  *   Set to zero on transmit and ignored on receipt.
615  */
616 struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *asoc,
617                                    const struct sctp_chunk *chunk)
618 {
619         struct sctp_chunk *retval;
620 
621         retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ACK, 0, 0, GFP_ATOMIC);
622 
623         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
624          *
625          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
626          * HEARTBEAT ACK, * etc.) to the same destination transport
627          * address from which it * received the DATA or control chunk
628          * to which it is replying.
629          *
630          * [COOKIE ACK back to where the COOKIE ECHO came from.]
631          */
632         if (retval && chunk)
633                 retval->transport = chunk->transport;
634 
635         return retval;
636 }
637 
638 /*
639  *  Appendix A: Explicit Congestion Notification:
640  *  CWR:
641  *
642  *  RFC 2481 details a specific bit for a sender to send in the header of
643  *  its next outbound TCP segment to indicate to its peer that it has
644  *  reduced its congestion window.  This is termed the CWR bit.  For
645  *  SCTP the same indication is made by including the CWR chunk.
646  *  This chunk contains one data element, i.e. the TSN number that
647  *  was sent in the ECNE chunk.  This element represents the lowest
648  *  TSN number in the datagram that was originally marked with the
649  *  CE bit.
650  *
651  *     0                   1                   2                   3
652  *     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
653  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
654  *    | Chunk Type=13 | Flags=00000000|    Chunk Length = 8           |
655  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
656  *    |                      Lowest TSN Number                        |
657  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
658  *
659  *     Note: The CWR is considered a Control chunk.
660  */
661 struct sctp_chunk *sctp_make_cwr(const struct sctp_association *asoc,
662                             const __u32 lowest_tsn,
663                             const struct sctp_chunk *chunk)
664 {
665         struct sctp_chunk *retval;
666         sctp_cwrhdr_t cwr;
667 
668         cwr.lowest_tsn = htonl(lowest_tsn);
669         retval = sctp_make_control(asoc, SCTP_CID_ECN_CWR, 0,
670                                    sizeof(sctp_cwrhdr_t), GFP_ATOMIC);
671 
672         if (!retval)
673                 goto nodata;
674 
675         retval->subh.ecn_cwr_hdr =
676                 sctp_addto_chunk(retval, sizeof(cwr), &cwr);
677 
678         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
679          *
680          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
681          * HEARTBEAT ACK, * etc.) to the same destination transport
682          * address from which it * received the DATA or control chunk
683          * to which it is replying.
684          *
685          * [Report a reduced congestion window back to where the ECNE
686          * came from.]
687          */
688         if (chunk)
689                 retval->transport = chunk->transport;
690 
691 nodata:
692         return retval;
693 }
694 
695 /* Make an ECNE chunk.  This is a congestion experienced report.  */
696 struct sctp_chunk *sctp_make_ecne(const struct sctp_association *asoc,
697                              const __u32 lowest_tsn)
698 {
699         struct sctp_chunk *retval;
700         sctp_ecnehdr_t ecne;
701 
702         ecne.lowest_tsn = htonl(lowest_tsn);
703         retval = sctp_make_control(asoc, SCTP_CID_ECN_ECNE, 0,
704                                    sizeof(sctp_ecnehdr_t), GFP_ATOMIC);
705         if (!retval)
706                 goto nodata;
707         retval->subh.ecne_hdr =
708                 sctp_addto_chunk(retval, sizeof(ecne), &ecne);
709 
710 nodata:
711         return retval;
712 }
713 
714 /* Make a DATA chunk for the given association from the provided
715  * parameters.  However, do not populate the data payload.
716  */
717 struct sctp_chunk *sctp_make_datafrag_empty(struct sctp_association *asoc,
718                                        const struct sctp_sndrcvinfo *sinfo,
719                                        int data_len, __u8 flags, __u16 ssn,
720                                        gfp_t gfp)
721 {
722         struct sctp_chunk *retval;
723         struct sctp_datahdr dp;
724         int chunk_len;
725 
726         /* We assign the TSN as LATE as possible, not here when
727          * creating the chunk.
728          */
729         dp.tsn = 0;
730         dp.stream = htons(sinfo->sinfo_stream);
731         dp.ppid   = sinfo->sinfo_ppid;
732 
733         /* Set the flags for an unordered send.  */
734         if (sinfo->sinfo_flags & SCTP_UNORDERED) {
735                 flags |= SCTP_DATA_UNORDERED;
736                 dp.ssn = 0;
737         } else
738                 dp.ssn = htons(ssn);
739 
740         chunk_len = sizeof(dp) + data_len;
741         retval = sctp_make_data(asoc, flags, chunk_len, gfp);
742         if (!retval)
743                 goto nodata;
744 
745         retval->subh.data_hdr = sctp_addto_chunk(retval, sizeof(dp), &dp);
746         memcpy(&retval->sinfo, sinfo, sizeof(struct sctp_sndrcvinfo));
747 
748 nodata:
749         return retval;
750 }
751 
752 /* Create a selective ackowledgement (SACK) for the given
753  * association.  This reports on which TSN's we've seen to date,
754  * including duplicates and gaps.
755  */
756 struct sctp_chunk *sctp_make_sack(const struct sctp_association *asoc)
757 {
758         struct sctp_chunk *retval;
759         struct sctp_sackhdr sack;
760         int len;
761         __u32 ctsn;
762         __u16 num_gabs, num_dup_tsns;
763         struct sctp_association *aptr = (struct sctp_association *)asoc;
764         struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
765         struct sctp_gap_ack_block gabs[SCTP_MAX_GABS];
766         struct sctp_transport *trans;
767 
768         memset(gabs, 0, sizeof(gabs));
769         ctsn = sctp_tsnmap_get_ctsn(map);
770 
771         pr_debug("%s: sackCTSNAck sent:0x%x\n", __func__, ctsn);
772 
773         /* How much room is needed in the chunk? */
774         num_gabs = sctp_tsnmap_num_gabs(map, gabs);
775         num_dup_tsns = sctp_tsnmap_num_dups(map);
776 
777         /* Initialize the SACK header.  */
778         sack.cum_tsn_ack            = htonl(ctsn);
779         sack.a_rwnd                 = htonl(asoc->a_rwnd);
780         sack.num_gap_ack_blocks     = htons(num_gabs);
781         sack.num_dup_tsns           = htons(num_dup_tsns);
782 
783         len = sizeof(sack)
784                 + sizeof(struct sctp_gap_ack_block) * num_gabs
785                 + sizeof(__u32) * num_dup_tsns;
786 
787         /* Create the chunk.  */
788         retval = sctp_make_control(asoc, SCTP_CID_SACK, 0, len, GFP_ATOMIC);
789         if (!retval)
790                 goto nodata;
791 
792         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
793          *
794          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
795          * HEARTBEAT ACK, etc.) to the same destination transport
796          * address from which it received the DATA or control chunk to
797          * which it is replying.  This rule should also be followed if
798          * the endpoint is bundling DATA chunks together with the
799          * reply chunk.
800          *
801          * However, when acknowledging multiple DATA chunks received
802          * in packets from different source addresses in a single
803          * SACK, the SACK chunk may be transmitted to one of the
804          * destination transport addresses from which the DATA or
805          * control chunks being acknowledged were received.
806          *
807          * [BUG:  We do not implement the following paragraph.
808          * Perhaps we should remember the last transport we used for a
809          * SACK and avoid that (if possible) if we have seen any
810          * duplicates. --piggy]
811          *
812          * When a receiver of a duplicate DATA chunk sends a SACK to a
813          * multi- homed endpoint it MAY be beneficial to vary the
814          * destination address and not use the source address of the
815          * DATA chunk.  The reason being that receiving a duplicate
816          * from a multi-homed endpoint might indicate that the return
817          * path (as specified in the source address of the DATA chunk)
818          * for the SACK is broken.
819          *
820          * [Send to the address from which we last received a DATA chunk.]
821          */
822         retval->transport = asoc->peer.last_data_from;
823 
824         retval->subh.sack_hdr =
825                 sctp_addto_chunk(retval, sizeof(sack), &sack);
826 
827         /* Add the gap ack block information.   */
828         if (num_gabs)
829                 sctp_addto_chunk(retval, sizeof(__u32) * num_gabs,
830                                  gabs);
831 
832         /* Add the duplicate TSN information.  */
833         if (num_dup_tsns) {
834                 aptr->stats.idupchunks += num_dup_tsns;
835                 sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns,
836                                  sctp_tsnmap_get_dups(map));
837         }
838         /* Once we have a sack generated, check to see what our sack
839          * generation is, if its 0, reset the transports to 0, and reset
840          * the association generation to 1
841          *
842          * The idea is that zero is never used as a valid generation for the
843          * association so no transport will match after a wrap event like this,
844          * Until the next sack
845          */
846         if (++aptr->peer.sack_generation == 0) {
847                 list_for_each_entry(trans, &asoc->peer.transport_addr_list,
848                                     transports)
849                         trans->sack_generation = 0;
850                 aptr->peer.sack_generation = 1;
851         }
852 nodata:
853         return retval;
854 }
855 
856 /* Make a SHUTDOWN chunk. */
857 struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
858                                       const struct sctp_chunk *chunk)
859 {
860         struct sctp_chunk *retval;
861         sctp_shutdownhdr_t shut;
862         __u32 ctsn;
863 
864         ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
865         shut.cum_tsn_ack = htonl(ctsn);
866 
867         retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN, 0,
868                                    sizeof(sctp_shutdownhdr_t), GFP_ATOMIC);
869         if (!retval)
870                 goto nodata;
871 
872         retval->subh.shutdown_hdr =
873                 sctp_addto_chunk(retval, sizeof(shut), &shut);
874 
875         if (chunk)
876                 retval->transport = chunk->transport;
877 nodata:
878         return retval;
879 }
880 
881 struct sctp_chunk *sctp_make_shutdown_ack(const struct sctp_association *asoc,
882                                      const struct sctp_chunk *chunk)
883 {
884         struct sctp_chunk *retval;
885 
886         retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_ACK, 0, 0,
887                                    GFP_ATOMIC);
888 
889         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
890          *
891          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
892          * HEARTBEAT ACK, * etc.) to the same destination transport
893          * address from which it * received the DATA or control chunk
894          * to which it is replying.
895          *
896          * [ACK back to where the SHUTDOWN came from.]
897          */
898         if (retval && chunk)
899                 retval->transport = chunk->transport;
900 
901         return retval;
902 }
903 
904 struct sctp_chunk *sctp_make_shutdown_complete(
905         const struct sctp_association *asoc,
906         const struct sctp_chunk *chunk)
907 {
908         struct sctp_chunk *retval;
909         __u8 flags = 0;
910 
911         /* Set the T-bit if we have no association (vtag will be
912          * reflected)
913          */
914         flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;
915 
916         retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags,
917                                    0, GFP_ATOMIC);
918 
919         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
920          *
921          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
922          * HEARTBEAT ACK, * etc.) to the same destination transport
923          * address from which it * received the DATA or control chunk
924          * to which it is replying.
925          *
926          * [Report SHUTDOWN COMPLETE back to where the SHUTDOWN ACK
927          * came from.]
928          */
929         if (retval && chunk)
930                 retval->transport = chunk->transport;
931 
932         return retval;
933 }
934 
935 /* Create an ABORT.  Note that we set the T bit if we have no
936  * association, except when responding to an INIT (sctpimpguide 2.41).
937  */
938 struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc,
939                               const struct sctp_chunk *chunk,
940                               const size_t hint)
941 {
942         struct sctp_chunk *retval;
943         __u8 flags = 0;
944 
945         /* Set the T-bit if we have no association and 'chunk' is not
946          * an INIT (vtag will be reflected).
947          */
948         if (!asoc) {
949                 if (chunk && chunk->chunk_hdr &&
950                     chunk->chunk_hdr->type == SCTP_CID_INIT)
951                         flags = 0;
952                 else
953                         flags = SCTP_CHUNK_FLAG_T;
954         }
955 
956         retval = sctp_make_control(asoc, SCTP_CID_ABORT, flags, hint,
957                                    GFP_ATOMIC);
958 
959         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
960          *
961          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
962          * HEARTBEAT ACK, * etc.) to the same destination transport
963          * address from which it * received the DATA or control chunk
964          * to which it is replying.
965          *
966          * [ABORT back to where the offender came from.]
967          */
968         if (retval && chunk)
969                 retval->transport = chunk->transport;
970 
971         return retval;
972 }
973 
974 /* Helper to create ABORT with a NO_USER_DATA error.  */
975 struct sctp_chunk *sctp_make_abort_no_data(
976         const struct sctp_association *asoc,
977         const struct sctp_chunk *chunk, __u32 tsn)
978 {
979         struct sctp_chunk *retval;
980         __be32 payload;
981 
982         retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t)
983                                  + sizeof(tsn));
984 
985         if (!retval)
986                 goto no_mem;
987 
988         /* Put the tsn back into network byte order.  */
989         payload = htonl(tsn);
990         sctp_init_cause(retval, SCTP_ERROR_NO_DATA, sizeof(payload));
991         sctp_addto_chunk(retval, sizeof(payload), (const void *)&payload);
992 
993         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
994          *
995          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
996          * HEARTBEAT ACK, * etc.) to the same destination transport
997          * address from which it * received the DATA or control chunk
998          * to which it is replying.
999          *
1000          * [ABORT back to where the offender came from.]
1001          */
1002         if (chunk)
1003                 retval->transport = chunk->transport;
1004 
1005 no_mem:
1006         return retval;
1007 }
1008 
1009 /* Helper to create ABORT with a SCTP_ERROR_USER_ABORT error.  */
1010 struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *asoc,
1011                                         struct msghdr *msg,
1012                                         size_t paylen)
1013 {
1014         struct sctp_chunk *retval;
1015         void *payload = NULL;
1016         int err;
1017 
1018         retval = sctp_make_abort(asoc, NULL, sizeof(sctp_errhdr_t) + paylen);
1019         if (!retval)
1020                 goto err_chunk;
1021 
1022         if (paylen) {
1023                 /* Put the msg_iov together into payload.  */
1024                 payload = kmalloc(paylen, GFP_KERNEL);
1025                 if (!payload)
1026                         goto err_payload;
1027 
1028                 err = memcpy_from_msg(payload, msg, paylen);
1029                 if (err < 0)
1030                         goto err_copy;
1031         }
1032 
1033         sctp_init_cause(retval, SCTP_ERROR_USER_ABORT, paylen);
1034         sctp_addto_chunk(retval, paylen, payload);
1035 
1036         if (paylen)
1037                 kfree(payload);
1038 
1039         return retval;
1040 
1041 err_copy:
1042         kfree(payload);
1043 err_payload:
1044         sctp_chunk_free(retval);
1045         retval = NULL;
1046 err_chunk:
1047         return retval;
1048 }
1049 
1050 /* Append bytes to the end of a parameter.  Will panic if chunk is not big
1051  * enough.
1052  */
1053 static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
1054                               const void *data)
1055 {
1056         void *target;
1057         int chunklen = ntohs(chunk->chunk_hdr->length);
1058 
1059         target = skb_put(chunk->skb, len);
1060 
1061         if (data)
1062                 memcpy(target, data, len);
1063         else
1064                 memset(target, 0, len);
1065 
1066         /* Adjust the chunk length field.  */
1067         chunk->chunk_hdr->length = htons(chunklen + len);
1068         chunk->chunk_end = skb_tail_pointer(chunk->skb);
1069 
1070         return target;
1071 }
1072 
1073 /* Make an ABORT chunk with a PROTOCOL VIOLATION cause code. */
1074 struct sctp_chunk *sctp_make_abort_violation(
1075         const struct sctp_association *asoc,
1076         const struct sctp_chunk *chunk,
1077         const __u8   *payload,
1078         const size_t paylen)
1079 {
1080         struct sctp_chunk  *retval;
1081         struct sctp_paramhdr phdr;
1082 
1083         retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t) + paylen
1084                                         + sizeof(sctp_paramhdr_t));
1085         if (!retval)
1086                 goto end;
1087 
1088         sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, paylen
1089                                         + sizeof(sctp_paramhdr_t));
1090 
1091         phdr.type = htons(chunk->chunk_hdr->type);
1092         phdr.length = chunk->chunk_hdr->length;
1093         sctp_addto_chunk(retval, paylen, payload);
1094         sctp_addto_param(retval, sizeof(sctp_paramhdr_t), &phdr);
1095 
1096 end:
1097         return retval;
1098 }
1099 
1100 struct sctp_chunk *sctp_make_violation_paramlen(
1101         const struct sctp_association *asoc,
1102         const struct sctp_chunk *chunk,
1103         struct sctp_paramhdr *param)
1104 {
1105         struct sctp_chunk *retval;
1106         static const char error[] = "The following parameter had invalid length:";
1107         size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t) +
1108                                 sizeof(sctp_paramhdr_t);
1109 
1110         retval = sctp_make_abort(asoc, chunk, payload_len);
1111         if (!retval)
1112                 goto nodata;
1113 
1114         sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION,
1115                         sizeof(error) + sizeof(sctp_paramhdr_t));
1116         sctp_addto_chunk(retval, sizeof(error), error);
1117         sctp_addto_param(retval, sizeof(sctp_paramhdr_t), param);
1118 
1119 nodata:
1120         return retval;
1121 }
1122 
1123 struct sctp_chunk *sctp_make_violation_max_retrans(
1124         const struct sctp_association *asoc,
1125         const struct sctp_chunk *chunk)
1126 {
1127         struct sctp_chunk *retval;
1128         static const char error[] = "Association exceeded its max_retans count";
1129         size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t);
1130 
1131         retval = sctp_make_abort(asoc, chunk, payload_len);
1132         if (!retval)
1133                 goto nodata;
1134 
1135         sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, sizeof(error));
1136         sctp_addto_chunk(retval, sizeof(error), error);
1137 
1138 nodata:
1139         return retval;
1140 }
1141 
1142 /* Make a HEARTBEAT chunk.  */
1143 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
1144                                   const struct sctp_transport *transport)
1145 {
1146         struct sctp_chunk *retval;
1147         sctp_sender_hb_info_t hbinfo;
1148 
1149         retval = sctp_make_control(asoc, SCTP_CID_HEARTBEAT, 0,
1150                                    sizeof(hbinfo), GFP_ATOMIC);
1151 
1152         if (!retval)
1153                 goto nodata;
1154 
1155         hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO;
1156         hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t));
1157         hbinfo.daddr = transport->ipaddr;
1158         hbinfo.sent_at = jiffies;
1159         hbinfo.hb_nonce = transport->hb_nonce;
1160 
1161         /* Cast away the 'const', as this is just telling the chunk
1162          * what transport it belongs to.
1163          */
1164         retval->transport = (struct sctp_transport *) transport;
1165         retval->subh.hbs_hdr = sctp_addto_chunk(retval, sizeof(hbinfo),
1166                                                 &hbinfo);
1167 
1168 nodata:
1169         return retval;
1170 }
1171 
1172 struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc,
1173                                       const struct sctp_chunk *chunk,
1174                                       const void *payload, const size_t paylen)
1175 {
1176         struct sctp_chunk *retval;
1177 
1178         retval  = sctp_make_control(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen,
1179                                     GFP_ATOMIC);
1180         if (!retval)
1181                 goto nodata;
1182 
1183         retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);
1184 
1185         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
1186          *
1187          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1188          * HEARTBEAT ACK, * etc.) to the same destination transport
1189          * address from which it * received the DATA or control chunk
1190          * to which it is replying.
1191          *
1192          * [HBACK back to where the HEARTBEAT came from.]
1193          */
1194         if (chunk)
1195                 retval->transport = chunk->transport;
1196 
1197 nodata:
1198         return retval;
1199 }
1200 
1201 /* Create an Operation Error chunk with the specified space reserved.
1202  * This routine can be used for containing multiple causes in the chunk.
1203  */
1204 static struct sctp_chunk *sctp_make_op_error_space(
1205         const struct sctp_association *asoc,
1206         const struct sctp_chunk *chunk,
1207         size_t size)
1208 {
1209         struct sctp_chunk *retval;
1210 
1211         retval = sctp_make_control(asoc, SCTP_CID_ERROR, 0,
1212                                    sizeof(sctp_errhdr_t) + size, GFP_ATOMIC);
1213         if (!retval)
1214                 goto nodata;
1215 
1216         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
1217          *
1218          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1219          * HEARTBEAT ACK, etc.) to the same destination transport
1220          * address from which it received the DATA or control chunk
1221          * to which it is replying.
1222          *
1223          */
1224         if (chunk)
1225                 retval->transport = chunk->transport;
1226 
1227 nodata:
1228         return retval;
1229 }
1230 
1231 /* Create an Operation Error chunk of a fixed size,
1232  * specifically, max(asoc->pathmtu, SCTP_DEFAULT_MAXSEGMENT)
1233  * This is a helper function to allocate an error chunk for
1234  * for those invalid parameter codes in which we may not want
1235  * to report all the errors, if the incoming chunk is large
1236  */
1237 static inline struct sctp_chunk *sctp_make_op_error_fixed(
1238         const struct sctp_association *asoc,
1239         const struct sctp_chunk *chunk)
1240 {
1241         size_t size = asoc ? asoc->pathmtu : 0;
1242 
1243         if (!size)
1244                 size = SCTP_DEFAULT_MAXSEGMENT;
1245 
1246         return sctp_make_op_error_space(asoc, chunk, size);
1247 }
1248 
1249 /* Create an Operation Error chunk.  */
1250 struct sctp_chunk *sctp_make_op_error(const struct sctp_association *asoc,
1251                                  const struct sctp_chunk *chunk,
1252                                  __be16 cause_code, const void *payload,
1253                                  size_t paylen, size_t reserve_tail)
1254 {
1255         struct sctp_chunk *retval;
1256 
1257         retval = sctp_make_op_error_space(asoc, chunk, paylen + reserve_tail);
1258         if (!retval)
1259                 goto nodata;
1260 
1261         sctp_init_cause(retval, cause_code, paylen + reserve_tail);
1262         sctp_addto_chunk(retval, paylen, payload);
1263         if (reserve_tail)
1264                 sctp_addto_param(retval, reserve_tail, NULL);
1265 
1266 nodata:
1267         return retval;
1268 }
1269 
1270 struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc)
1271 {
1272         struct sctp_chunk *retval;
1273         struct sctp_hmac *hmac_desc;
1274         struct sctp_authhdr auth_hdr;
1275         __u8 *hmac;
1276 
1277         /* Get the first hmac that the peer told us to use */
1278         hmac_desc = sctp_auth_asoc_get_hmac(asoc);
1279         if (unlikely(!hmac_desc))
1280                 return NULL;
1281 
1282         retval = sctp_make_control(asoc, SCTP_CID_AUTH, 0,
1283                         hmac_desc->hmac_len + sizeof(sctp_authhdr_t),
1284                         GFP_ATOMIC);
1285         if (!retval)
1286                 return NULL;
1287 
1288         auth_hdr.hmac_id = htons(hmac_desc->hmac_id);
1289         auth_hdr.shkey_id = htons(asoc->active_key_id);
1290 
1291         retval->subh.auth_hdr = sctp_addto_chunk(retval, sizeof(sctp_authhdr_t),
1292                                                 &auth_hdr);
1293 
1294         hmac = skb_put(retval->skb, hmac_desc->hmac_len);
1295         memset(hmac, 0, hmac_desc->hmac_len);
1296 
1297         /* Adjust the chunk header to include the empty MAC */
1298         retval->chunk_hdr->length =
1299                 htons(ntohs(retval->chunk_hdr->length) + hmac_desc->hmac_len);
1300         retval->chunk_end = skb_tail_pointer(retval->skb);
1301 
1302         return retval;
1303 }
1304 
1305 
1306 /********************************************************************
1307  * 2nd Level Abstractions
1308  ********************************************************************/
1309 
1310 /* Turn an skb into a chunk.
1311  * FIXME: Eventually move the structure directly inside the skb->cb[].
1312  *
1313  * sctpimpguide-05.txt Section 2.8.2
1314  * M1) Each time a new DATA chunk is transmitted
1315  * set the 'TSN.Missing.Report' count for that TSN to 0. The
1316  * 'TSN.Missing.Report' count will be used to determine missing chunks
1317  * and when to fast retransmit.
1318  *
1319  */
1320 struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
1321                             const struct sctp_association *asoc,
1322                             struct sock *sk, gfp_t gfp)
1323 {
1324         struct sctp_chunk *retval;
1325 
1326         retval = kmem_cache_zalloc(sctp_chunk_cachep, gfp);
1327 
1328         if (!retval)
1329                 goto nodata;
1330         if (!sk)
1331                 pr_debug("%s: chunkifying skb:%p w/o an sk\n", __func__, skb);
1332 
1333         INIT_LIST_HEAD(&retval->list);
1334         retval->skb             = skb;
1335         retval->asoc            = (struct sctp_association *)asoc;
1336         retval->singleton       = 1;
1337 
1338         retval->fast_retransmit = SCTP_CAN_FRTX;
1339 
1340         /* Polish the bead hole.  */
1341         INIT_LIST_HEAD(&retval->transmitted_list);
1342         INIT_LIST_HEAD(&retval->frag_list);
1343         SCTP_DBG_OBJCNT_INC(chunk);
1344         atomic_set(&retval->refcnt, 1);
1345 
1346 nodata:
1347         return retval;
1348 }
1349 
1350 /* Set chunk->source and dest based on the IP header in chunk->skb.  */
1351 void sctp_init_addrs(struct sctp_chunk *chunk, union sctp_addr *src,
1352                      union sctp_addr *dest)
1353 {
1354         memcpy(&chunk->source, src, sizeof(union sctp_addr));
1355         memcpy(&chunk->dest, dest, sizeof(union sctp_addr));
1356 }
1357 
1358 /* Extract the source address from a chunk.  */
1359 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk)
1360 {
1361         /* If we have a known transport, use that.  */
1362         if (chunk->transport) {
1363                 return &chunk->transport->ipaddr;
1364         } else {
1365                 /* Otherwise, extract it from the IP header.  */
1366                 return &chunk->source;
1367         }
1368 }
1369 
1370 /* Create a new chunk, setting the type and flags headers from the
1371  * arguments, reserving enough space for a 'paylen' byte payload.
1372  */
1373 static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc,
1374                                             __u8 type, __u8 flags, int paylen,
1375                                             gfp_t gfp)
1376 {
1377         struct sctp_chunk *retval;
1378         sctp_chunkhdr_t *chunk_hdr;
1379         struct sk_buff *skb;
1380         struct sock *sk;
1381 
1382         /* No need to allocate LL here, as this is only a chunk. */
1383         skb = alloc_skb(WORD_ROUND(sizeof(sctp_chunkhdr_t) + paylen), gfp);
1384         if (!skb)
1385                 goto nodata;
1386 
1387         /* Make room for the chunk header.  */
1388         chunk_hdr = (sctp_chunkhdr_t *)skb_put(skb, sizeof(sctp_chunkhdr_t));
1389         chunk_hdr->type   = type;
1390         chunk_hdr->flags  = flags;
1391         chunk_hdr->length = htons(sizeof(sctp_chunkhdr_t));
1392 
1393         sk = asoc ? asoc->base.sk : NULL;
1394         retval = sctp_chunkify(skb, asoc, sk, gfp);
1395         if (!retval) {
1396                 kfree_skb(skb);
1397                 goto nodata;
1398         }
1399 
1400         retval->chunk_hdr = chunk_hdr;
1401         retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(struct sctp_chunkhdr);
1402 
1403         /* Determine if the chunk needs to be authenticated */
1404         if (sctp_auth_send_cid(type, asoc))
1405                 retval->auth = 1;
1406 
1407         return retval;
1408 nodata:
1409         return NULL;
1410 }
1411 
1412 static struct sctp_chunk *sctp_make_data(const struct sctp_association *asoc,
1413                                          __u8 flags, int paylen, gfp_t gfp)
1414 {
1415         return _sctp_make_chunk(asoc, SCTP_CID_DATA, flags, paylen, gfp);
1416 }
1417 
1418 static struct sctp_chunk *sctp_make_control(const struct sctp_association *asoc,
1419                                             __u8 type, __u8 flags, int paylen,
1420                                             gfp_t gfp)
1421 {
1422         struct sctp_chunk *chunk;
1423 
1424         chunk = _sctp_make_chunk(asoc, type, flags, paylen, gfp);
1425         if (chunk)
1426                 sctp_control_set_owner_w(chunk);
1427 
1428         return chunk;
1429 }
1430 
1431 /* Release the memory occupied by a chunk.  */
1432 static void sctp_chunk_destroy(struct sctp_chunk *chunk)
1433 {
1434         BUG_ON(!list_empty(&chunk->list));
1435         list_del_init(&chunk->transmitted_list);
1436 
1437         consume_skb(chunk->skb);
1438         consume_skb(chunk->auth_chunk);
1439 
1440         SCTP_DBG_OBJCNT_DEC(chunk);
1441         kmem_cache_free(sctp_chunk_cachep, chunk);
1442 }
1443 
1444 /* Possibly, free the chunk.  */
1445 void sctp_chunk_free(struct sctp_chunk *chunk)
1446 {
1447         /* Release our reference on the message tracker. */
1448         if (chunk->msg)
1449                 sctp_datamsg_put(chunk->msg);
1450 
1451         sctp_chunk_put(chunk);
1452 }
1453 
1454 /* Grab a reference to the chunk. */
1455 void sctp_chunk_hold(struct sctp_chunk *ch)
1456 {
1457         atomic_inc(&ch->refcnt);
1458 }
1459 
1460 /* Release a reference to the chunk. */
1461 void sctp_chunk_put(struct sctp_chunk *ch)
1462 {
1463         if (atomic_dec_and_test(&ch->refcnt))
1464                 sctp_chunk_destroy(ch);
1465 }
1466 
1467 /* Append bytes to the end of a chunk.  Will panic if chunk is not big
1468  * enough.
1469  */
1470 void *sctp_addto_chunk(struct sctp_chunk *chunk, int len, const void *data)
1471 {
1472         void *target;
1473         void *padding;
1474         int chunklen = ntohs(chunk->chunk_hdr->length);
1475         int padlen = WORD_ROUND(chunklen) - chunklen;
1476 
1477         padding = skb_put(chunk->skb, padlen);
1478         target = skb_put(chunk->skb, len);
1479 
1480         memset(padding, 0, padlen);
1481         memcpy(target, 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         ssize_t copied;
1511 
1512         /* Make room in chunk for data.  */
1513         target = skb_put(chunk->skb, len);
1514 
1515         /* Copy data (whole iovec) into chunk */
1516         copied = copy_from_iter(target, len, from);
1517         if (copied != len)
1518                 return -EFAULT;
1519 
1520         /* Adjust the chunk length field.  */
1521         chunk->chunk_hdr->length =
1522                 htons(ntohs(chunk->chunk_hdr->length) + len);
1523         chunk->chunk_end = skb_tail_pointer(chunk->skb);
1524 
1525         return 0;
1526 }
1527 
1528 /* Helper function to assign a TSN if needed.  This assumes that both
1529  * the data_hdr and association have already been assigned.
1530  */
1531 void sctp_chunk_assign_ssn(struct sctp_chunk *chunk)
1532 {
1533         struct sctp_datamsg *msg;
1534         struct sctp_chunk *lchunk;
1535         struct sctp_stream *stream;
1536         __u16 ssn;
1537         __u16 sid;
1538 
1539         if (chunk->has_ssn)
1540                 return;
1541 
1542         /* All fragments will be on the same stream */
1543         sid = ntohs(chunk->subh.data_hdr->stream);
1544         stream = &chunk->asoc->ssnmap->out;
1545 
1546         /* Now assign the sequence number to the entire message.
1547          * All fragments must have the same stream sequence number.
1548          */
1549         msg = chunk->msg;
1550         list_for_each_entry(lchunk, &msg->chunks, frag_list) {
1551                 if (lchunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
1552                         ssn = 0;
1553                 } else {
1554                         if (lchunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG)
1555                                 ssn = sctp_ssn_next(stream, sid);
1556                         else
1557                                 ssn = sctp_ssn_peek(stream, sid);
1558                 }
1559 
1560                 lchunk->subh.data_hdr->ssn = htons(ssn);
1561                 lchunk->has_ssn = 1;
1562         }
1563 }
1564 
1565 /* Helper function to assign a TSN if needed.  This assumes that both
1566  * the data_hdr and association have already been assigned.
1567  */
1568 void sctp_chunk_assign_tsn(struct sctp_chunk *chunk)
1569 {
1570         if (!chunk->has_tsn) {
1571                 /* This is the last possible instant to
1572                  * assign a TSN.
1573                  */
1574                 chunk->subh.data_hdr->tsn =
1575                         htonl(sctp_association_get_next_tsn(chunk->asoc));
1576                 chunk->has_tsn = 1;
1577         }
1578 }
1579 
1580 /* Create a CLOSED association to use with an incoming packet.  */
1581 struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *ep,
1582                                         struct sctp_chunk *chunk,
1583                                         gfp_t gfp)
1584 {
1585         struct sctp_association *asoc;
1586         struct sk_buff *skb;
1587         sctp_scope_t scope;
1588         struct sctp_af *af;
1589 
1590         /* Create the bare association.  */
1591         scope = sctp_scope(sctp_source(chunk));
1592         asoc = sctp_association_new(ep, ep->base.sk, scope, gfp);
1593         if (!asoc)
1594                 goto nodata;
1595         asoc->temp = 1;
1596         skb = chunk->skb;
1597         /* Create an entry for the source address of the packet.  */
1598         af = sctp_get_af_specific(ipver2af(ip_hdr(skb)->version));
1599         if (unlikely(!af))
1600                 goto fail;
1601         af->from_skb(&asoc->c.peer_addr, skb, 1);
1602 nodata:
1603         return asoc;
1604 
1605 fail:
1606         sctp_association_free(asoc);
1607         return NULL;
1608 }
1609 
1610 /* Build a cookie representing asoc.
1611  * This INCLUDES the param header needed to put the cookie in the INIT ACK.
1612  */
1613 static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
1614                                       const struct sctp_association *asoc,
1615                                       const struct sctp_chunk *init_chunk,
1616                                       int *cookie_len,
1617                                       const __u8 *raw_addrs, int addrs_len)
1618 {
1619         sctp_cookie_param_t *retval;
1620         struct sctp_signed_cookie *cookie;
1621         int headersize, bodysize;
1622 
1623         /* Header size is static data prior to the actual cookie, including
1624          * any padding.
1625          */
1626         headersize = sizeof(sctp_paramhdr_t) +
1627                      (sizeof(struct sctp_signed_cookie) -
1628                       sizeof(struct sctp_cookie));
1629         bodysize = sizeof(struct sctp_cookie)
1630                 + ntohs(init_chunk->chunk_hdr->length) + addrs_len;
1631 
1632         /* Pad out the cookie to a multiple to make the signature
1633          * functions simpler to write.
1634          */
1635         if (bodysize % SCTP_COOKIE_MULTIPLE)
1636                 bodysize += SCTP_COOKIE_MULTIPLE
1637                         - (bodysize % SCTP_COOKIE_MULTIPLE);
1638         *cookie_len = headersize + bodysize;
1639 
1640         /* Clear this memory since we are sending this data structure
1641          * out on the network.
1642          */
1643         retval = kzalloc(*cookie_len, GFP_ATOMIC);
1644         if (!retval)
1645                 goto nodata;
1646 
1647         cookie = (struct sctp_signed_cookie *) retval->body;
1648 
1649         /* Set up the parameter header.  */
1650         retval->p.type = SCTP_PARAM_STATE_COOKIE;
1651         retval->p.length = htons(*cookie_len);
1652 
1653         /* Copy the cookie part of the association itself.  */
1654         cookie->c = asoc->c;
1655         /* Save the raw address list length in the cookie. */
1656         cookie->c.raw_addr_list_len = addrs_len;
1657 
1658         /* Remember PR-SCTP capability. */
1659         cookie->c.prsctp_capable = asoc->peer.prsctp_capable;
1660 
1661         /* Save adaptation indication in the cookie. */
1662         cookie->c.adaptation_ind = asoc->peer.adaptation_ind;
1663 
1664         /* Set an expiration time for the cookie.  */
1665         cookie->c.expiration = ktime_add(asoc->cookie_life,
1666                                          ktime_get_real());
1667 
1668         /* Copy the peer's init packet.  */
1669         memcpy(&cookie->c.peer_init[0], init_chunk->chunk_hdr,
1670                ntohs(init_chunk->chunk_hdr->length));
1671 
1672         /* Copy the raw local address list of the association. */
1673         memcpy((__u8 *)&cookie->c.peer_init[0] +
1674                ntohs(init_chunk->chunk_hdr->length), raw_addrs, addrs_len);
1675 
1676         if (sctp_sk(ep->base.sk)->hmac) {
1677                 SHASH_DESC_ON_STACK(desc, sctp_sk(ep->base.sk)->hmac);
1678                 int err;
1679 
1680                 /* Sign the message.  */
1681                 desc->tfm = sctp_sk(ep->base.sk)->hmac;
1682                 desc->flags = 0;
1683 
1684                 err = crypto_shash_setkey(desc->tfm, ep->secret_key,
1685                                           sizeof(ep->secret_key)) ?:
1686                       crypto_shash_digest(desc, (u8 *)&cookie->c, bodysize,
1687                                           cookie->signature);
1688                 shash_desc_zero(desc);
1689                 if (err)
1690                         goto free_cookie;
1691         }
1692 
1693         return retval;
1694 
1695 free_cookie:
1696         kfree(retval);
1697 nodata:
1698         *cookie_len = 0;
1699         return NULL;
1700 }
1701 
1702 /* Unpack the cookie from COOKIE ECHO chunk, recreating the association.  */
1703 struct sctp_association *sctp_unpack_cookie(
1704         const struct sctp_endpoint *ep,
1705         const struct sctp_association *asoc,
1706         struct sctp_chunk *chunk, gfp_t gfp,
1707         int *error, struct sctp_chunk **errp)
1708 {
1709         struct sctp_association *retval = NULL;
1710         struct sctp_signed_cookie *cookie;
1711         struct sctp_cookie *bear_cookie;
1712         int headersize, bodysize, fixed_size;
1713         __u8 *digest = ep->digest;
1714         unsigned int len;
1715         sctp_scope_t scope;
1716         struct sk_buff *skb = chunk->skb;
1717         ktime_t kt;
1718 
1719         /* Header size is static data prior to the actual cookie, including
1720          * any padding.
1721          */
1722         headersize = sizeof(sctp_chunkhdr_t) +
1723                      (sizeof(struct sctp_signed_cookie) -
1724                       sizeof(struct sctp_cookie));
1725         bodysize = ntohs(chunk->chunk_hdr->length) - headersize;
1726         fixed_size = headersize + sizeof(struct sctp_cookie);
1727 
1728         /* Verify that the chunk looks like it even has a cookie.
1729          * There must be enough room for our cookie and our peer's
1730          * INIT chunk.
1731          */
1732         len = ntohs(chunk->chunk_hdr->length);
1733         if (len < fixed_size + sizeof(struct sctp_chunkhdr))
1734                 goto malformed;
1735 
1736         /* Verify that the cookie has been padded out. */
1737         if (bodysize % SCTP_COOKIE_MULTIPLE)
1738                 goto malformed;
1739 
1740         /* Process the cookie.  */
1741         cookie = chunk->subh.cookie_hdr;
1742         bear_cookie = &cookie->c;
1743 
1744         if (!sctp_sk(ep->base.sk)->hmac)
1745                 goto no_hmac;
1746 
1747         /* Check the signature.  */
1748         {
1749                 SHASH_DESC_ON_STACK(desc, sctp_sk(ep->base.sk)->hmac);
1750                 int err;
1751 
1752                 desc->tfm = sctp_sk(ep->base.sk)->hmac;
1753                 desc->flags = 0;
1754 
1755                 err = crypto_shash_setkey(desc->tfm, ep->secret_key,
1756                                           sizeof(ep->secret_key)) ?:
1757                       crypto_shash_digest(desc, (u8 *)bear_cookie, bodysize,
1758                                           digest);
1759                 shash_desc_zero(desc);
1760 
1761                 if (err) {
1762                         *error = -SCTP_IERROR_NOMEM;
1763                         goto fail;
1764                 }
1765         }
1766 
1767         if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
1768                 *error = -SCTP_IERROR_BAD_SIG;
1769                 goto fail;
1770         }
1771 
1772 no_hmac:
1773         /* IG Section 2.35.2:
1774          *  3) Compare the port numbers and the verification tag contained
1775          *     within the COOKIE ECHO chunk to the actual port numbers and the
1776          *     verification tag within the SCTP common header of the received
1777          *     packet. If these values do not match the packet MUST be silently
1778          *     discarded,
1779          */
1780         if (ntohl(chunk->sctp_hdr->vtag) != bear_cookie->my_vtag) {
1781                 *error = -SCTP_IERROR_BAD_TAG;
1782                 goto fail;
1783         }
1784 
1785         if (chunk->sctp_hdr->source != bear_cookie->peer_addr.v4.sin_port ||
1786             ntohs(chunk->sctp_hdr->dest) != bear_cookie->my_port) {
1787                 *error = -SCTP_IERROR_BAD_PORTS;
1788                 goto fail;
1789         }
1790 
1791         /* Check to see if the cookie is stale.  If there is already
1792          * an association, there is no need to check cookie's expiration
1793          * for init collision case of lost COOKIE ACK.
1794          * If skb has been timestamped, then use the stamp, otherwise
1795          * use current time.  This introduces a small possibility that
1796          * that a cookie may be considered expired, but his would only slow
1797          * down the new association establishment instead of every packet.
1798          */
1799         if (sock_flag(ep->base.sk, SOCK_TIMESTAMP))
1800                 kt = skb_get_ktime(skb);
1801         else
1802                 kt = ktime_get_real();
1803 
1804         if (!asoc && ktime_before(bear_cookie->expiration, kt)) {
1805                 /*
1806                  * Section 3.3.10.3 Stale Cookie Error (3)
1807                  *
1808                  * Cause of error
1809                  * ---------------
1810                  * Stale Cookie Error:  Indicates the receipt of a valid State
1811                  * Cookie that has expired.
1812                  */
1813                 len = ntohs(chunk->chunk_hdr->length);
1814                 *errp = sctp_make_op_error_space(asoc, chunk, len);
1815                 if (*errp) {
1816                         suseconds_t usecs = ktime_to_us(ktime_sub(kt, bear_cookie->expiration));
1817                         __be32 n = htonl(usecs);
1818 
1819                         sctp_init_cause(*errp, SCTP_ERROR_STALE_COOKIE,
1820                                         sizeof(n));
1821                         sctp_addto_chunk(*errp, sizeof(n), &n);
1822                         *error = -SCTP_IERROR_STALE_COOKIE;
1823                 } else
1824                         *error = -SCTP_IERROR_NOMEM;
1825 
1826                 goto fail;
1827         }
1828 
1829         /* Make a new base association.  */
1830         scope = sctp_scope(sctp_source(chunk));
1831         retval = sctp_association_new(ep, ep->base.sk, scope, gfp);
1832         if (!retval) {
1833                 *error = -SCTP_IERROR_NOMEM;
1834                 goto fail;
1835         }
1836 
1837         /* Set up our peer's port number.  */
1838         retval->peer.port = ntohs(chunk->sctp_hdr->source);
1839 
1840         /* Populate the association from the cookie.  */
1841         memcpy(&retval->c, bear_cookie, sizeof(*bear_cookie));
1842 
1843         if (sctp_assoc_set_bind_addr_from_cookie(retval, bear_cookie,
1844                                                  GFP_ATOMIC) < 0) {
1845                 *error = -SCTP_IERROR_NOMEM;
1846                 goto fail;
1847         }
1848 
1849         /* Also, add the destination address. */
1850         if (list_empty(&retval->base.bind_addr.address_list)) {
1851                 sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest,
1852                                    sizeof(chunk->dest), SCTP_ADDR_SRC,
1853                                    GFP_ATOMIC);
1854         }
1855 
1856         retval->next_tsn = retval->c.initial_tsn;
1857         retval->ctsn_ack_point = retval->next_tsn - 1;
1858         retval->addip_serial = retval->c.initial_tsn;
1859         retval->adv_peer_ack_point = retval->ctsn_ack_point;
1860         retval->peer.prsctp_capable = retval->c.prsctp_capable;
1861         retval->peer.adaptation_ind = retval->c.adaptation_ind;
1862 
1863         /* The INIT stuff will be done by the side effects.  */
1864         return retval;
1865 
1866 fail:
1867         if (retval)
1868                 sctp_association_free(retval);
1869 
1870         return NULL;
1871 
1872 malformed:
1873         /* Yikes!  The packet is either corrupt or deliberately
1874          * malformed.
1875          */
1876         *error = -SCTP_IERROR_MALFORMED;
1877         goto fail;
1878 }
1879 
1880 /********************************************************************
1881  * 3rd Level Abstractions
1882  ********************************************************************/
1883 
1884 struct __sctp_missing {
1885         __be32 num_missing;
1886         __be16 type;
1887 }  __packed;
1888 
1889 /*
1890  * Report a missing mandatory parameter.
1891  */
1892 static int sctp_process_missing_param(const struct sctp_association *asoc,
1893                                       sctp_param_t paramtype,
1894                                       struct sctp_chunk *chunk,
1895                                       struct sctp_chunk **errp)
1896 {
1897         struct __sctp_missing report;
1898         __u16 len;
1899 
1900         len = WORD_ROUND(sizeof(report));
1901 
1902         /* Make an ERROR chunk, preparing enough room for
1903          * returning multiple unknown parameters.
1904          */
1905         if (!*errp)
1906                 *errp = sctp_make_op_error_space(asoc, chunk, len);
1907 
1908         if (*errp) {
1909                 report.num_missing = htonl(1);
1910                 report.type = paramtype;
1911                 sctp_init_cause(*errp, SCTP_ERROR_MISS_PARAM,
1912                                 sizeof(report));
1913                 sctp_addto_chunk(*errp, sizeof(report), &report);
1914         }
1915 
1916         /* Stop processing this chunk. */
1917         return 0;
1918 }
1919 
1920 /* Report an Invalid Mandatory Parameter.  */
1921 static int sctp_process_inv_mandatory(const struct sctp_association *asoc,
1922                                       struct sctp_chunk *chunk,
1923                                       struct sctp_chunk **errp)
1924 {
1925         /* Invalid Mandatory Parameter Error has no payload. */
1926 
1927         if (!*errp)
1928                 *errp = sctp_make_op_error_space(asoc, chunk, 0);
1929 
1930         if (*errp)
1931                 sctp_init_cause(*errp, SCTP_ERROR_INV_PARAM, 0);
1932 
1933         /* Stop processing this chunk. */
1934         return 0;
1935 }
1936 
1937 static int sctp_process_inv_paramlength(const struct sctp_association *asoc,
1938                                         struct sctp_paramhdr *param,
1939                                         const struct sctp_chunk *chunk,
1940                                         struct sctp_chunk **errp)
1941 {
1942         /* This is a fatal error.  Any accumulated non-fatal errors are
1943          * not reported.
1944          */
1945         if (*errp)
1946                 sctp_chunk_free(*errp);
1947 
1948         /* Create an error chunk and fill it in with our payload. */
1949         *errp = sctp_make_violation_paramlen(asoc, chunk, param);
1950 
1951         return 0;
1952 }
1953 
1954 
1955 /* Do not attempt to handle the HOST_NAME parm.  However, do
1956  * send back an indicator to the peer.
1957  */
1958 static int sctp_process_hn_param(const struct sctp_association *asoc,
1959                                  union sctp_params param,
1960                                  struct sctp_chunk *chunk,
1961                                  struct sctp_chunk **errp)
1962 {
1963         __u16 len = ntohs(param.p->length);
1964 
1965         /* Processing of the HOST_NAME parameter will generate an
1966          * ABORT.  If we've accumulated any non-fatal errors, they
1967          * would be unrecognized parameters and we should not include
1968          * them in the ABORT.
1969          */
1970         if (*errp)
1971                 sctp_chunk_free(*errp);
1972 
1973         *errp = sctp_make_op_error_space(asoc, chunk, len);
1974 
1975         if (*errp) {
1976                 sctp_init_cause(*errp, SCTP_ERROR_DNS_FAILED, len);
1977                 sctp_addto_chunk(*errp, len, param.v);
1978         }
1979 
1980         /* Stop processing this chunk. */
1981         return 0;
1982 }
1983 
1984 static int sctp_verify_ext_param(struct net *net, union sctp_params param)
1985 {
1986         __u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
1987         int have_auth = 0;
1988         int have_asconf = 0;
1989         int i;
1990 
1991         for (i = 0; i < num_ext; i++) {
1992                 switch (param.ext->chunks[i]) {
1993                 case SCTP_CID_AUTH:
1994                         have_auth = 1;
1995                         break;
1996                 case SCTP_CID_ASCONF:
1997                 case SCTP_CID_ASCONF_ACK:
1998                         have_asconf = 1;
1999                         break;
2000                 }
2001         }
2002 
2003         /* ADD-IP Security: The draft requires us to ABORT or ignore the
2004          * INIT/INIT-ACK if ADD-IP is listed, but AUTH is not.  Do this
2005          * only if ADD-IP is turned on and we are not backward-compatible
2006          * mode.
2007          */
2008         if (net->sctp.addip_noauth)
2009                 return 1;
2010 
2011         if (net->sctp.addip_enable && !have_auth && have_asconf)
2012                 return 0;
2013 
2014         return 1;
2015 }
2016 
2017 static void sctp_process_ext_param(struct sctp_association *asoc,
2018                                     union sctp_params param)
2019 {
2020         struct net *net = sock_net(asoc->base.sk);
2021         __u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2022         int i;
2023 
2024         for (i = 0; i < num_ext; i++) {
2025                 switch (param.ext->chunks[i]) {
2026                 case SCTP_CID_FWD_TSN:
2027                         if (net->sctp.prsctp_enable && !asoc->peer.prsctp_capable)
2028                                     asoc->peer.prsctp_capable = 1;
2029                         break;
2030                 case SCTP_CID_AUTH:
2031                         /* if the peer reports AUTH, assume that he
2032                          * supports AUTH.
2033                          */
2034                         if (asoc->ep->auth_enable)
2035                                 asoc->peer.auth_capable = 1;
2036                         break;
2037                 case SCTP_CID_ASCONF:
2038                 case SCTP_CID_ASCONF_ACK:
2039                         if (net->sctp.addip_enable)
2040                                 asoc->peer.asconf_capable = 1;
2041                         break;
2042                 default:
2043                         break;
2044                 }
2045         }
2046 }
2047 
2048 /* RFC 3.2.1 & the Implementers Guide 2.2.
2049  *
2050  * The Parameter Types are encoded such that the
2051  * highest-order two bits specify the action that must be
2052  * taken if the processing endpoint does not recognize the
2053  * Parameter Type.
2054  *
2055  * 00 - Stop processing this parameter; do not process any further
2056  *      parameters within this chunk
2057  *
2058  * 01 - Stop processing this parameter, do not process any further
2059  *      parameters within this chunk, and report the unrecognized
2060  *      parameter in an 'Unrecognized Parameter' ERROR chunk.
2061  *
2062  * 10 - Skip this parameter and continue processing.
2063  *
2064  * 11 - Skip this parameter and continue processing but
2065  *      report the unrecognized parameter in an
2066  *      'Unrecognized Parameter' ERROR chunk.
2067  *
2068  * Return value:
2069  *      SCTP_IERROR_NO_ERROR - continue with the chunk
2070  *      SCTP_IERROR_ERROR    - stop and report an error.
2071  *      SCTP_IERROR_NOMEME   - out of memory.
2072  */
2073 static sctp_ierror_t sctp_process_unk_param(const struct sctp_association *asoc,
2074                                             union sctp_params param,
2075                                             struct sctp_chunk *chunk,
2076                                             struct sctp_chunk **errp)
2077 {
2078         int retval = SCTP_IERROR_NO_ERROR;
2079 
2080         switch (param.p->type & SCTP_PARAM_ACTION_MASK) {
2081         case SCTP_PARAM_ACTION_DISCARD:
2082                 retval =  SCTP_IERROR_ERROR;
2083                 break;
2084         case SCTP_PARAM_ACTION_SKIP:
2085                 break;
2086         case SCTP_PARAM_ACTION_DISCARD_ERR:
2087                 retval =  SCTP_IERROR_ERROR;
2088                 /* Fall through */
2089         case SCTP_PARAM_ACTION_SKIP_ERR:
2090                 /* Make an ERROR chunk, preparing enough room for
2091                  * returning multiple unknown parameters.
2092                  */
2093                 if (NULL == *errp)
2094                         *errp = sctp_make_op_error_fixed(asoc, chunk);
2095 
2096                 if (*errp) {
2097                         if (!sctp_init_cause_fixed(*errp, SCTP_ERROR_UNKNOWN_PARAM,
2098                                         WORD_ROUND(ntohs(param.p->length))))
2099                                 sctp_addto_chunk_fixed(*errp,
2100                                                 WORD_ROUND(ntohs(param.p->length)),
2101                                                 param.v);
2102                 } else {
2103                         /* If there is no memory for generating the ERROR
2104                          * report as specified, an ABORT will be triggered
2105                          * to the peer and the association won't be
2106                          * established.
2107                          */
2108                         retval = SCTP_IERROR_NOMEM;
2109                 }
2110                 break;
2111         default:
2112                 break;
2113         }
2114 
2115         return retval;
2116 }
2117 
2118 /* Verify variable length parameters
2119  * Return values:
2120  *      SCTP_IERROR_ABORT - trigger an ABORT
2121  *      SCTP_IERROR_NOMEM - out of memory (abort)
2122  *      SCTP_IERROR_ERROR - stop processing, trigger an ERROR
2123  *      SCTP_IERROR_NO_ERROR - continue with the chunk
2124  */
2125 static sctp_ierror_t sctp_verify_param(struct net *net,
2126                                         const struct sctp_endpoint *ep,
2127                                         const struct sctp_association *asoc,
2128                                         union sctp_params param,
2129                                         sctp_cid_t cid,
2130                                         struct sctp_chunk *chunk,
2131                                         struct sctp_chunk **err_chunk)
2132 {
2133         struct sctp_hmac_algo_param *hmacs;
2134         int retval = SCTP_IERROR_NO_ERROR;
2135         __u16 n_elt, id = 0;
2136         int i;
2137 
2138         /* FIXME - This routine is not looking at each parameter per the
2139          * chunk type, i.e., unrecognized parameters should be further
2140          * identified based on the chunk id.
2141          */
2142 
2143         switch (param.p->type) {
2144         case SCTP_PARAM_IPV4_ADDRESS:
2145         case SCTP_PARAM_IPV6_ADDRESS:
2146         case SCTP_PARAM_COOKIE_PRESERVATIVE:
2147         case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2148         case SCTP_PARAM_STATE_COOKIE:
2149         case SCTP_PARAM_HEARTBEAT_INFO:
2150         case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2151         case SCTP_PARAM_ECN_CAPABLE:
2152         case SCTP_PARAM_ADAPTATION_LAYER_IND:
2153                 break;
2154 
2155         case SCTP_PARAM_SUPPORTED_EXT:
2156                 if (!sctp_verify_ext_param(net, param))
2157                         return SCTP_IERROR_ABORT;
2158                 break;
2159 
2160         case SCTP_PARAM_SET_PRIMARY:
2161                 if (net->sctp.addip_enable)
2162                         break;
2163                 goto fallthrough;
2164 
2165         case SCTP_PARAM_HOST_NAME_ADDRESS:
2166                 /* Tell the peer, we won't support this param.  */
2167                 sctp_process_hn_param(asoc, param, chunk, err_chunk);
2168                 retval = SCTP_IERROR_ABORT;
2169                 break;
2170 
2171         case SCTP_PARAM_FWD_TSN_SUPPORT:
2172                 if (net->sctp.prsctp_enable)
2173                         break;
2174                 goto fallthrough;
2175 
2176         case SCTP_PARAM_RANDOM:
2177                 if (!ep->auth_enable)
2178                         goto fallthrough;
2179 
2180                 /* SCTP-AUTH: Secion 6.1
2181                  * If the random number is not 32 byte long the association
2182                  * MUST be aborted.  The ABORT chunk SHOULD contain the error
2183                  * cause 'Protocol Violation'.
2184                  */
2185                 if (SCTP_AUTH_RANDOM_LENGTH !=
2186                         ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) {
2187                         sctp_process_inv_paramlength(asoc, param.p,
2188                                                         chunk, err_chunk);
2189                         retval = SCTP_IERROR_ABORT;
2190                 }
2191                 break;
2192 
2193         case SCTP_PARAM_CHUNKS:
2194                 if (!ep->auth_enable)
2195                         goto fallthrough;
2196 
2197                 /* SCTP-AUTH: Section 3.2
2198                  * The CHUNKS parameter MUST be included once in the INIT or
2199                  *  INIT-ACK chunk if the sender wants to receive authenticated
2200                  *  chunks.  Its maximum length is 260 bytes.
2201                  */
2202                 if (260 < ntohs(param.p->length)) {
2203                         sctp_process_inv_paramlength(asoc, param.p,
2204                                                      chunk, err_chunk);
2205                         retval = SCTP_IERROR_ABORT;
2206                 }
2207                 break;
2208 
2209         case SCTP_PARAM_HMAC_ALGO:
2210                 if (!ep->auth_enable)
2211                         goto fallthrough;
2212 
2213                 hmacs = (struct sctp_hmac_algo_param *)param.p;
2214                 n_elt = (ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) >> 1;
2215 
2216                 /* SCTP-AUTH: Section 6.1
2217                  * The HMAC algorithm based on SHA-1 MUST be supported and
2218                  * included in the HMAC-ALGO parameter.
2219                  */
2220                 for (i = 0; i < n_elt; i++) {
2221                         id = ntohs(hmacs->hmac_ids[i]);
2222 
2223                         if (id == SCTP_AUTH_HMAC_ID_SHA1)
2224                                 break;
2225                 }
2226 
2227                 if (id != SCTP_AUTH_HMAC_ID_SHA1) {
2228                         sctp_process_inv_paramlength(asoc, param.p, chunk,
2229                                                      err_chunk);
2230                         retval = SCTP_IERROR_ABORT;
2231                 }
2232                 break;
2233 fallthrough:
2234         default:
2235                 pr_debug("%s: unrecognized param:%d for chunk:%d\n",
2236                          __func__, ntohs(param.p->type), cid);
2237 
2238                 retval = sctp_process_unk_param(asoc, param, chunk, err_chunk);
2239                 break;
2240         }
2241         return retval;
2242 }
2243 
2244 /* Verify the INIT packet before we process it.  */
2245 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
2246                      const struct sctp_association *asoc, sctp_cid_t cid,
2247                      sctp_init_chunk_t *peer_init, struct sctp_chunk *chunk,
2248                      struct sctp_chunk **errp)
2249 {
2250         union sctp_params param;
2251         bool has_cookie = false;
2252         int result;
2253 
2254         /* Check for missing mandatory parameters. Note: Initial TSN is
2255          * also mandatory, but is not checked here since the valid range
2256          * is 0..2**32-1. RFC4960, section 3.3.3.
2257          */
2258         if (peer_init->init_hdr.num_outbound_streams == 0 ||
2259             peer_init->init_hdr.num_inbound_streams == 0 ||
2260             peer_init->init_hdr.init_tag == 0 ||
2261             ntohl(peer_init->init_hdr.a_rwnd) < SCTP_DEFAULT_MINWINDOW)
2262                 return sctp_process_inv_mandatory(asoc, chunk, errp);
2263 
2264         sctp_walk_params(param, peer_init, init_hdr.params) {
2265                 if (param.p->type == SCTP_PARAM_STATE_COOKIE)
2266                         has_cookie = true;
2267         }
2268 
2269         /* There is a possibility that a parameter length was bad and
2270          * in that case we would have stoped walking the parameters.
2271          * The current param.p would point at the bad one.
2272          * Current consensus on the mailing list is to generate a PROTOCOL
2273          * VIOLATION error.  We build the ERROR chunk here and let the normal
2274          * error handling code build and send the packet.
2275          */
2276         if (param.v != (void *)chunk->chunk_end)
2277                 return sctp_process_inv_paramlength(asoc, param.p, chunk, errp);
2278 
2279         /* The only missing mandatory param possible today is
2280          * the state cookie for an INIT-ACK chunk.
2281          */
2282         if ((SCTP_CID_INIT_ACK == cid) && !has_cookie)
2283                 return sctp_process_missing_param(asoc, SCTP_PARAM_STATE_COOKIE,
2284                                                   chunk, errp);
2285 
2286         /* Verify all the variable length parameters */
2287         sctp_walk_params(param, peer_init, init_hdr.params) {
2288                 result = sctp_verify_param(net, ep, asoc, param, cid,
2289                                            chunk, errp);
2290                 switch (result) {
2291                 case SCTP_IERROR_ABORT:
2292                 case SCTP_IERROR_NOMEM:
2293                         return 0;
2294                 case SCTP_IERROR_ERROR:
2295                         return 1;
2296                 case SCTP_IERROR_NO_ERROR:
2297                 default:
2298                         break;
2299                 }
2300 
2301         } /* for (loop through all parameters) */
2302 
2303         return 1;
2304 }
2305 
2306 /* Unpack the parameters in an INIT packet into an association.
2307  * Returns 0 on failure, else success.
2308  * FIXME:  This is an association method.
2309  */
2310 int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,
2311                       const union sctp_addr *peer_addr,
2312                       sctp_init_chunk_t *peer_init, gfp_t gfp)
2313 {
2314         struct net *net = sock_net(asoc->base.sk);
2315         union sctp_params param;
2316         struct sctp_transport *transport;
2317         struct list_head *pos, *temp;
2318         struct sctp_af *af;
2319         union sctp_addr addr;
2320         char *cookie;
2321         int src_match = 0;
2322 
2323         /* We must include the address that the INIT packet came from.
2324          * This is the only address that matters for an INIT packet.
2325          * When processing a COOKIE ECHO, we retrieve the from address
2326          * of the INIT from the cookie.
2327          */
2328 
2329         /* This implementation defaults to making the first transport
2330          * added as the primary transport.  The source address seems to
2331          * be a a better choice than any of the embedded addresses.
2332          */
2333         if (!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
2334                 goto nomem;
2335 
2336         if (sctp_cmp_addr_exact(sctp_source(chunk), peer_addr))
2337                 src_match = 1;
2338 
2339         /* Process the initialization parameters.  */
2340         sctp_walk_params(param, peer_init, init_hdr.params) {
2341                 if (!src_match && (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
2342                     param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
2343                         af = sctp_get_af_specific(param_type2af(param.p->type));
2344                         af->from_addr_param(&addr, param.addr,
2345                                             chunk->sctp_hdr->source, 0);
2346                         if (sctp_cmp_addr_exact(sctp_source(chunk), &addr))
2347                                 src_match = 1;
2348                 }
2349 
2350                 if (!sctp_process_param(asoc, param, peer_addr, gfp))
2351                         goto clean_up;
2352         }
2353 
2354         /* source address of chunk may not match any valid address */
2355         if (!src_match)
2356                 goto clean_up;
2357 
2358         /* AUTH: After processing the parameters, make sure that we
2359          * have all the required info to potentially do authentications.
2360          */
2361         if (asoc->peer.auth_capable && (!asoc->peer.peer_random ||
2362                                         !asoc->peer.peer_hmacs))
2363                 asoc->peer.auth_capable = 0;
2364 
2365         /* In a non-backward compatible mode, if the peer claims
2366          * support for ADD-IP but not AUTH,  the ADD-IP spec states
2367          * that we MUST ABORT the association. Section 6.  The section
2368          * also give us an option to silently ignore the packet, which
2369          * is what we'll do here.
2370          */
2371         if (!net->sctp.addip_noauth &&
2372              (asoc->peer.asconf_capable && !asoc->peer.auth_capable)) {
2373                 asoc->peer.addip_disabled_mask |= (SCTP_PARAM_ADD_IP |
2374                                                   SCTP_PARAM_DEL_IP |
2375                                                   SCTP_PARAM_SET_PRIMARY);
2376                 asoc->peer.asconf_capable = 0;
2377                 goto clean_up;
2378         }
2379 
2380         /* Walk list of transports, removing transports in the UNKNOWN state. */
2381         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2382                 transport = list_entry(pos, struct sctp_transport, transports);
2383                 if (transport->state == SCTP_UNKNOWN) {
2384                         sctp_assoc_rm_peer(asoc, transport);
2385                 }
2386         }
2387 
2388         /* The fixed INIT headers are always in network byte
2389          * order.
2390          */
2391         asoc->peer.i.init_tag =
2392                 ntohl(peer_init->init_hdr.init_tag);
2393         asoc->peer.i.a_rwnd =
2394                 ntohl(peer_init->init_hdr.a_rwnd);
2395         asoc->peer.i.num_outbound_streams =
2396                 ntohs(peer_init->init_hdr.num_outbound_streams);
2397         asoc->peer.i.num_inbound_streams =
2398                 ntohs(peer_init->init_hdr.num_inbound_streams);
2399         asoc->peer.i.initial_tsn =
2400                 ntohl(peer_init->init_hdr.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         /* Allocate storage for the negotiated streams if it is not a temporary
2454          * association.
2455          */
2456         if (!asoc->temp) {
2457                 int error;
2458 
2459                 asoc->ssnmap = sctp_ssnmap_new(asoc->c.sinit_max_instreams,
2460                                                asoc->c.sinit_num_ostreams, gfp);
2461                 if (!asoc->ssnmap)
2462                         goto clean_up;
2463 
2464                 error = sctp_assoc_set_id(asoc, gfp);
2465                 if (error)
2466                         goto clean_up;
2467         }
2468 
2469         /* ADDIP Section 4.1 ASCONF Chunk Procedures
2470          *
2471          * When an endpoint has an ASCONF signaled change to be sent to the
2472          * remote endpoint it should do the following:
2473          * ...
2474          * A2) A serial number should be assigned to the Chunk. The serial
2475          * number should be a monotonically increasing number. All serial
2476          * numbers are defined to be initialized at the start of the
2477          * association to the same value as the Initial TSN.
2478          */
2479         asoc->peer.addip_serial = asoc->peer.i.initial_tsn - 1;
2480         return 1;
2481 
2482 clean_up:
2483         /* Release the transport structures. */
2484         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2485                 transport = list_entry(pos, struct sctp_transport, transports);
2486                 if (transport->state != SCTP_ACTIVE)
2487                         sctp_assoc_rm_peer(asoc, transport);
2488         }
2489 
2490 nomem:
2491         return 0;
2492 }
2493 
2494 
2495 /* Update asoc with the option described in param.
2496  *
2497  * RFC2960 3.3.2.1 Optional/Variable Length Parameters in INIT
2498  *
2499  * asoc is the association to update.
2500  * param is the variable length parameter to use for update.
2501  * cid tells us if this is an INIT, INIT ACK or COOKIE ECHO.
2502  * If the current packet is an INIT we want to minimize the amount of
2503  * work we do.  In particular, we should not build transport
2504  * structures for the addresses.
2505  */
2506 static int sctp_process_param(struct sctp_association *asoc,
2507                               union sctp_params param,
2508                               const union sctp_addr *peer_addr,
2509                               gfp_t gfp)
2510 {
2511         struct net *net = sock_net(asoc->base.sk);
2512         union sctp_addr addr;
2513         int i;
2514         __u16 sat;
2515         int retval = 1;
2516         sctp_scope_t scope;
2517         u32 stale;
2518         struct sctp_af *af;
2519         union sctp_addr_param *addr_param;
2520         struct sctp_transport *t;
2521         struct sctp_endpoint *ep = asoc->ep;
2522 
2523         /* We maintain all INIT parameters in network byte order all the
2524          * time.  This allows us to not worry about whether the parameters
2525          * came from a fresh INIT, and INIT ACK, or were stored in a cookie.
2526          */
2527         switch (param.p->type) {
2528         case SCTP_PARAM_IPV6_ADDRESS:
2529                 if (PF_INET6 != asoc->base.sk->sk_family)
2530                         break;
2531                 goto do_addr_param;
2532 
2533         case SCTP_PARAM_IPV4_ADDRESS:
2534                 /* v4 addresses are not allowed on v6-only socket */
2535                 if (ipv6_only_sock(asoc->base.sk))
2536                         break;
2537 do_addr_param:
2538                 af = sctp_get_af_specific(param_type2af(param.p->type));
2539                 af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
2540                 scope = sctp_scope(peer_addr);
2541                 if (sctp_in_scope(net, &addr, scope))
2542                         if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
2543                                 return 0;
2544                 break;
2545 
2546         case SCTP_PARAM_COOKIE_PRESERVATIVE:
2547                 if (!net->sctp.cookie_preserve_enable)
2548                         break;
2549 
2550                 stale = ntohl(param.life->lifespan_increment);
2551 
2552                 /* Suggested Cookie Life span increment's unit is msec,
2553                  * (1/1000sec).
2554                  */
2555                 asoc->cookie_life = ktime_add_ms(asoc->cookie_life, stale);
2556                 break;
2557 
2558         case SCTP_PARAM_HOST_NAME_ADDRESS:
2559                 pr_debug("%s: unimplemented SCTP_HOST_NAME_ADDRESS\n", __func__);
2560                 break;
2561 
2562         case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2563                 /* Turn off the default values first so we'll know which
2564                  * ones are really set by the peer.
2565                  */
2566                 asoc->peer.ipv4_address = 0;
2567                 asoc->peer.ipv6_address = 0;
2568 
2569                 /* Assume that peer supports the address family
2570                  * by which it sends a packet.
2571                  */
2572                 if (peer_addr->sa.sa_family == AF_INET6)
2573                         asoc->peer.ipv6_address = 1;
2574                 else if (peer_addr->sa.sa_family == AF_INET)
2575                         asoc->peer.ipv4_address = 1;
2576 
2577                 /* Cycle through address types; avoid divide by 0. */
2578                 sat = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2579                 if (sat)
2580                         sat /= sizeof(__u16);
2581 
2582                 for (i = 0; i < sat; ++i) {
2583                         switch (param.sat->types[i]) {
2584                         case SCTP_PARAM_IPV4_ADDRESS:
2585                                 asoc->peer.ipv4_address = 1;
2586                                 break;
2587 
2588                         case SCTP_PARAM_IPV6_ADDRESS:
2589                                 if (PF_INET6 == asoc->base.sk->sk_family)
2590                                         asoc->peer.ipv6_address = 1;
2591                                 break;
2592 
2593                         case SCTP_PARAM_HOST_NAME_ADDRESS:
2594                                 asoc->peer.hostname_address = 1;
2595                                 break;
2596 
2597                         default: /* Just ignore anything else.  */
2598                                 break;
2599                         }
2600                 }
2601                 break;
2602 
2603         case SCTP_PARAM_STATE_COOKIE:
2604                 asoc->peer.cookie_len =
2605                         ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2606                 asoc->peer.cookie = param.cookie->body;
2607                 break;
2608 
2609         case SCTP_PARAM_HEARTBEAT_INFO:
2610                 /* Would be odd to receive, but it causes no problems. */
2611                 break;
2612 
2613         case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2614                 /* Rejected during verify stage. */
2615                 break;
2616 
2617         case SCTP_PARAM_ECN_CAPABLE:
2618                 asoc->peer.ecn_capable = 1;
2619                 break;
2620 
2621         case SCTP_PARAM_ADAPTATION_LAYER_IND:
2622                 asoc->peer.adaptation_ind = ntohl(param.aind->adaptation_ind);
2623                 break;
2624 
2625         case SCTP_PARAM_SET_PRIMARY:
2626                 if (!net->sctp.addip_enable)
2627                         goto fall_through;
2628 
2629                 addr_param = param.v + sizeof(sctp_addip_param_t);
2630 
2631                 af = sctp_get_af_specific(param_type2af(addr_param->p.type));
2632                 if (af == NULL)
2633                         break;
2634 
2635                 af->from_addr_param(&addr, addr_param,
2636                                     htons(asoc->peer.port), 0);
2637 
2638                 /* if the address is invalid, we can't process it.
2639                  * XXX: see spec for what to do.
2640                  */
2641                 if (!af->addr_valid(&addr, NULL, NULL))
2642                         break;
2643 
2644                 t = sctp_assoc_lookup_paddr(asoc, &addr);
2645                 if (!t)
2646                         break;
2647 
2648                 sctp_assoc_set_primary(asoc, t);
2649                 break;
2650 
2651         case SCTP_PARAM_SUPPORTED_EXT:
2652                 sctp_process_ext_param(asoc, param);
2653                 break;
2654 
2655         case SCTP_PARAM_FWD_TSN_SUPPORT:
2656                 if (net->sctp.prsctp_enable) {
2657                         asoc->peer.prsctp_capable = 1;
2658                         break;
2659                 }
2660                 /* Fall Through */
2661                 goto fall_through;
2662 
2663         case SCTP_PARAM_RANDOM:
2664                 if (!ep->auth_enable)
2665                         goto fall_through;
2666 
2667                 /* Save peer's random parameter */
2668                 asoc->peer.peer_random = kmemdup(param.p,
2669                                             ntohs(param.p->length), gfp);
2670                 if (!asoc->peer.peer_random) {
2671                         retval = 0;
2672                         break;
2673                 }
2674                 break;
2675 
2676         case SCTP_PARAM_HMAC_ALGO:
2677                 if (!ep->auth_enable)
2678                         goto fall_through;
2679 
2680                 /* Save peer's HMAC list */
2681                 asoc->peer.peer_hmacs = kmemdup(param.p,
2682                                             ntohs(param.p->length), gfp);
2683                 if (!asoc->peer.peer_hmacs) {
2684                         retval = 0;
2685                         break;
2686                 }
2687 
2688                 /* Set the default HMAC the peer requested*/
2689                 sctp_auth_asoc_set_default_hmac(asoc, param.hmac_algo);
2690                 break;
2691 
2692         case SCTP_PARAM_CHUNKS:
2693                 if (!ep->auth_enable)
2694                         goto fall_through;
2695 
2696                 asoc->peer.peer_chunks = kmemdup(param.p,
2697                                             ntohs(param.p->length), gfp);
2698                 if (!asoc->peer.peer_chunks)
2699                         retval = 0;
2700                 break;
2701 fall_through:
2702         default:
2703                 /* Any unrecognized parameters should have been caught
2704                  * and handled by sctp_verify_param() which should be
2705                  * called prior to this routine.  Simply log the error
2706                  * here.
2707                  */
2708                 pr_debug("%s: ignoring param:%d for association:%p.\n",
2709                          __func__, ntohs(param.p->type), asoc);
2710                 break;
2711         }
2712 
2713         return retval;
2714 }
2715 
2716 /* Select a new verification tag.  */
2717 __u32 sctp_generate_tag(const struct sctp_endpoint *ep)
2718 {
2719         /* I believe that this random number generator complies with RFC1750.
2720          * A tag of 0 is reserved for special cases (e.g. INIT).
2721          */
2722         __u32 x;
2723 
2724         do {
2725                 get_random_bytes(&x, sizeof(__u32));
2726         } while (x == 0);
2727 
2728         return x;
2729 }
2730 
2731 /* Select an initial TSN to send during startup.  */
2732 __u32 sctp_generate_tsn(const struct sctp_endpoint *ep)
2733 {
2734         __u32 retval;
2735 
2736         get_random_bytes(&retval, sizeof(__u32));
2737         return retval;
2738 }
2739 
2740 /*
2741  * ADDIP 3.1.1 Address Configuration Change Chunk (ASCONF)
2742  *      0                   1                   2                   3
2743  *      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
2744  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2745  *     | Type = 0xC1   |  Chunk Flags  |      Chunk Length             |
2746  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2747  *     |                       Serial Number                           |
2748  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2749  *     |                    Address Parameter                          |
2750  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2751  *     |                     ASCONF Parameter #1                       |
2752  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2753  *     \                                                               \
2754  *     /                             ....                              /
2755  *     \                                                               \
2756  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2757  *     |                     ASCONF Parameter #N                       |
2758  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2759  *
2760  * Address Parameter and other parameter will not be wrapped in this function
2761  */
2762 static struct sctp_chunk *sctp_make_asconf(struct sctp_association *asoc,
2763                                            union sctp_addr *addr,
2764                                            int vparam_len)
2765 {
2766         sctp_addiphdr_t asconf;
2767         struct sctp_chunk *retval;
2768         int length = sizeof(asconf) + vparam_len;
2769         union sctp_addr_param addrparam;
2770         int addrlen;
2771         struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
2772 
2773         addrlen = af->to_addr_param(addr, &addrparam);
2774         if (!addrlen)
2775                 return NULL;
2776         length += addrlen;
2777 
2778         /* Create the chunk.  */
2779         retval = sctp_make_control(asoc, SCTP_CID_ASCONF, 0, length,
2780                                    GFP_ATOMIC);
2781         if (!retval)
2782                 return NULL;
2783 
2784         asconf.serial = htonl(asoc->addip_serial++);
2785 
2786         retval->subh.addip_hdr =
2787                 sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2788         retval->param_hdr.v =
2789                 sctp_addto_chunk(retval, addrlen, &addrparam);
2790 
2791         return retval;
2792 }
2793 
2794 /* ADDIP
2795  * 3.2.1 Add IP Address
2796  *      0                   1                   2                   3
2797  *      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
2798  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2799  *     |        Type = 0xC001          |    Length = Variable          |
2800  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2801  *     |               ASCONF-Request Correlation ID                   |
2802  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2803  *     |                       Address Parameter                       |
2804  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2805  *
2806  * 3.2.2 Delete IP Address
2807  *      0                   1                   2                   3
2808  *      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
2809  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2810  *     |        Type = 0xC002          |    Length = Variable          |
2811  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2812  *     |               ASCONF-Request Correlation ID                   |
2813  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2814  *     |                       Address Parameter                       |
2815  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2816  *
2817  */
2818 struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *asoc,
2819                                               union sctp_addr         *laddr,
2820                                               struct sockaddr         *addrs,
2821                                               int                     addrcnt,
2822                                               __be16                  flags)
2823 {
2824         sctp_addip_param_t      param;
2825         struct sctp_chunk       *retval;
2826         union sctp_addr_param   addr_param;
2827         union sctp_addr         *addr;
2828         void                    *addr_buf;
2829         struct sctp_af          *af;
2830         int                     paramlen = sizeof(param);
2831         int                     addr_param_len = 0;
2832         int                     totallen = 0;
2833         int                     i;
2834         int                     del_pickup = 0;
2835 
2836         /* Get total length of all the address parameters. */
2837         addr_buf = addrs;
2838         for (i = 0; i < addrcnt; i++) {
2839                 addr = addr_buf;
2840                 af = sctp_get_af_specific(addr->v4.sin_family);
2841                 addr_param_len = af->to_addr_param(addr, &addr_param);
2842 
2843                 totallen += paramlen;
2844                 totallen += addr_param_len;
2845 
2846                 addr_buf += af->sockaddr_len;
2847                 if (asoc->asconf_addr_del_pending && !del_pickup) {
2848                         /* reuse the parameter length from the same scope one */
2849                         totallen += paramlen;
2850                         totallen += addr_param_len;
2851                         del_pickup = 1;
2852 
2853                         pr_debug("%s: picked same-scope del_pending addr, "
2854                                  "totallen for all addresses is %d\n",
2855                                  __func__, totallen);
2856                 }
2857         }
2858 
2859         /* Create an asconf chunk with the required length. */
2860         retval = sctp_make_asconf(asoc, laddr, totallen);
2861         if (!retval)
2862                 return NULL;
2863 
2864         /* Add the address parameters to the asconf chunk. */
2865         addr_buf = addrs;
2866         for (i = 0; i < addrcnt; i++) {
2867                 addr = addr_buf;
2868                 af = sctp_get_af_specific(addr->v4.sin_family);
2869                 addr_param_len = af->to_addr_param(addr, &addr_param);
2870                 param.param_hdr.type = flags;
2871                 param.param_hdr.length = htons(paramlen + addr_param_len);
2872                 param.crr_id = i;
2873 
2874                 sctp_addto_chunk(retval, paramlen, &param);
2875                 sctp_addto_chunk(retval, addr_param_len, &addr_param);
2876 
2877                 addr_buf += af->sockaddr_len;
2878         }
2879         if (flags == SCTP_PARAM_ADD_IP && del_pickup) {
2880                 addr = asoc->asconf_addr_del_pending;
2881                 af = sctp_get_af_specific(addr->v4.sin_family);
2882                 addr_param_len = af->to_addr_param(addr, &addr_param);
2883                 param.param_hdr.type = SCTP_PARAM_DEL_IP;
2884                 param.param_hdr.length = htons(paramlen + addr_param_len);
2885                 param.crr_id = i;
2886 
2887                 sctp_addto_chunk(retval, paramlen, &param);
2888                 sctp_addto_chunk(retval, addr_param_len, &addr_param);
2889         }
2890         return retval;
2891 }
2892 
2893 /* ADDIP
2894  * 3.2.4 Set Primary IP Address
2895  *      0                   1                   2                   3
2896  *      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
2897  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2898  *     |        Type =0xC004           |    Length = Variable          |
2899  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2900  *     |               ASCONF-Request Correlation ID                   |
2901  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2902  *     |                       Address Parameter                       |
2903  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2904  *
2905  * Create an ASCONF chunk with Set Primary IP address parameter.
2906  */
2907 struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
2908                                              union sctp_addr *addr)
2909 {
2910         sctp_addip_param_t      param;
2911         struct sctp_chunk       *retval;
2912         int                     len = sizeof(param);
2913         union sctp_addr_param   addrparam;
2914         int                     addrlen;
2915         struct sctp_af          *af = sctp_get_af_specific(addr->v4.sin_family);
2916 
2917         addrlen = af->to_addr_param(addr, &addrparam);
2918         if (!addrlen)
2919                 return NULL;
2920         len += addrlen;
2921 
2922         /* Create the chunk and make asconf header. */
2923         retval = sctp_make_asconf(asoc, addr, len);
2924         if (!retval)
2925                 return NULL;
2926 
2927         param.param_hdr.type = SCTP_PARAM_SET_PRIMARY;
2928         param.param_hdr.length = htons(len);
2929         param.crr_id = 0;
2930 
2931         sctp_addto_chunk(retval, sizeof(param), &param);
2932         sctp_addto_chunk(retval, addrlen, &addrparam);
2933 
2934         return retval;
2935 }
2936 
2937 /* ADDIP 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
2938  *      0                   1                   2                   3
2939  *      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
2940  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2941  *     | Type = 0x80   |  Chunk Flags  |      Chunk Length             |
2942  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2943  *     |                       Serial Number                           |
2944  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2945  *     |                 ASCONF Parameter Response#1                   |
2946  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2947  *     \                                                               \
2948  *     /                             ....                              /
2949  *     \                                                               \
2950  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2951  *     |                 ASCONF Parameter Response#N                   |
2952  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2953  *
2954  * Create an ASCONF_ACK chunk with enough space for the parameter responses.
2955  */
2956 static struct sctp_chunk *sctp_make_asconf_ack(const struct sctp_association *asoc,
2957                                                __u32 serial, int vparam_len)
2958 {
2959         sctp_addiphdr_t         asconf;
2960         struct sctp_chunk       *retval;
2961         int                     length = sizeof(asconf) + vparam_len;
2962 
2963         /* Create the chunk.  */
2964         retval = sctp_make_control(asoc, SCTP_CID_ASCONF_ACK, 0, length,
2965                                    GFP_ATOMIC);
2966         if (!retval)
2967                 return NULL;
2968 
2969         asconf.serial = htonl(serial);
2970 
2971         retval->subh.addip_hdr =
2972                 sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2973 
2974         return retval;
2975 }
2976 
2977 /* Add response parameters to an ASCONF_ACK chunk. */
2978 static void sctp_add_asconf_response(struct sctp_chunk *chunk, __be32 crr_id,
2979                               __be16 err_code, sctp_addip_param_t *asconf_param)
2980 {
2981         sctp_addip_param_t      ack_param;
2982         sctp_errhdr_t           err_param;
2983         int                     asconf_param_len = 0;
2984         int                     err_param_len = 0;
2985         __be16                  response_type;
2986 
2987         if (SCTP_ERROR_NO_ERROR == err_code) {
2988                 response_type = SCTP_PARAM_SUCCESS_REPORT;
2989         } else {
2990                 response_type = SCTP_PARAM_ERR_CAUSE;
2991                 err_param_len = sizeof(err_param);
2992                 if (asconf_param)
2993                         asconf_param_len =
2994                                  ntohs(asconf_param->param_hdr.length);
2995         }
2996 
2997         /* Add Success Indication or Error Cause Indication parameter. */
2998         ack_param.param_hdr.type = response_type;
2999         ack_param.param_hdr.length = htons(sizeof(ack_param) +
3000                                            err_param_len +
3001                                            asconf_param_len);
3002         ack_param.crr_id = crr_id;
3003         sctp_addto_chunk(chunk, sizeof(ack_param), &ack_param);
3004 
3005         if (SCTP_ERROR_NO_ERROR == err_code)
3006                 return;
3007 
3008         /* Add Error Cause parameter. */
3009         err_param.cause = err_code;
3010         err_param.length = htons(err_param_len + asconf_param_len);
3011         sctp_addto_chunk(chunk, err_param_len, &err_param);
3012 
3013         /* Add the failed TLV copied from ASCONF chunk. */
3014         if (asconf_param)
3015                 sctp_addto_chunk(chunk, asconf_param_len, asconf_param);
3016 }
3017 
3018 /* Process a asconf parameter. */
3019 static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
3020                                        struct sctp_chunk *asconf,
3021                                        sctp_addip_param_t *asconf_param)
3022 {
3023         struct sctp_transport *peer;
3024         struct sctp_af *af;
3025         union sctp_addr addr;
3026         union sctp_addr_param *addr_param;
3027 
3028         addr_param = (void *)asconf_param + sizeof(sctp_addip_param_t);
3029 
3030         if (asconf_param->param_hdr.type != SCTP_PARAM_ADD_IP &&
3031             asconf_param->param_hdr.type != SCTP_PARAM_DEL_IP &&
3032             asconf_param->param_hdr.type != SCTP_PARAM_SET_PRIMARY)
3033                 return SCTP_ERROR_UNKNOWN_PARAM;
3034 
3035         switch (addr_param->p.type) {
3036         case SCTP_PARAM_IPV6_ADDRESS:
3037                 if (!asoc->peer.ipv6_address)
3038                         return SCTP_ERROR_DNS_FAILED;
3039                 break;
3040         case SCTP_PARAM_IPV4_ADDRESS:
3041                 if (!asoc->peer.ipv4_address)
3042                         return SCTP_ERROR_DNS_FAILED;
3043                 break;
3044         default:
3045                 return SCTP_ERROR_DNS_FAILED;
3046         }
3047 
3048         af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3049         if (unlikely(!af))
3050                 return SCTP_ERROR_DNS_FAILED;
3051 
3052         af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);
3053 
3054         /* ADDIP 4.2.1  This parameter MUST NOT contain a broadcast
3055          * or multicast address.
3056          * (note: wildcard is permitted and requires special handling so
3057          *  make sure we check for that)
3058          */
3059         if (!af->is_any(&addr) && !af->addr_valid(&addr, NULL, asconf->skb))
3060                 return SCTP_ERROR_DNS_FAILED;
3061 
3062         switch (asconf_param->param_hdr.type) {
3063         case SCTP_PARAM_ADD_IP:
3064                 /* Section 4.2.1:
3065                  * If the address 0.0.0.0 or ::0 is provided, the source
3066                  * address of the packet MUST be added.
3067                  */
3068                 if (af->is_any(&addr))
3069                         memcpy(&addr, &asconf->source, sizeof(addr));
3070 
3071                 /* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
3072                  * request and does not have the local resources to add this
3073                  * new address to the association, it MUST return an Error
3074                  * Cause TLV set to the new error code 'Operation Refused
3075                  * Due to Resource Shortage'.
3076                  */
3077 
3078                 peer = sctp_assoc_add_peer(asoc, &addr, GFP_ATOMIC, SCTP_UNCONFIRMED);
3079                 if (!peer)
3080                         return SCTP_ERROR_RSRC_LOW;
3081 
3082                 /* Start the heartbeat timer. */
3083                 sctp_transport_reset_hb_timer(peer);
3084                 asoc->new_transport = peer;
3085                 break;
3086         case SCTP_PARAM_DEL_IP:
3087                 /* ADDIP 4.3 D7) If a request is received to delete the
3088                  * last remaining IP address of a peer endpoint, the receiver
3089                  * MUST send an Error Cause TLV with the error cause set to the
3090                  * new error code 'Request to Delete Last Remaining IP Address'.
3091                  */
3092                 if (asoc->peer.transport_count == 1)
3093                         return SCTP_ERROR_DEL_LAST_IP;
3094 
3095                 /* ADDIP 4.3 D8) If a request is received to delete an IP
3096                  * address which is also the source address of the IP packet
3097                  * which contained the ASCONF chunk, the receiver MUST reject
3098                  * this request. To reject the request the receiver MUST send
3099                  * an Error Cause TLV set to the new error code 'Request to
3100                  * Delete Source IP Address'
3101                  */
3102                 if (sctp_cmp_addr_exact(&asconf->source, &addr))
3103                         return SCTP_ERROR_DEL_SRC_IP;
3104 
3105                 /* Section 4.2.2
3106                  * If the address 0.0.0.0 or ::0 is provided, all
3107                  * addresses of the peer except the source address of the
3108                  * packet MUST be deleted.
3109                  */
3110                 if (af->is_any(&addr)) {
3111                         sctp_assoc_set_primary(asoc, asconf->transport);
3112                         sctp_assoc_del_nonprimary_peers(asoc,
3113                                                         asconf->transport);
3114                         return SCTP_ERROR_NO_ERROR;
3115                 }
3116 
3117                 /* If the address is not part of the association, the
3118                  * ASCONF-ACK with Error Cause Indication Parameter
3119                  * which including cause of Unresolvable Address should
3120                  * be sent.
3121                  */
3122                 peer = sctp_assoc_lookup_paddr(asoc, &addr);
3123                 if (!peer)
3124                         return SCTP_ERROR_DNS_FAILED;
3125 
3126                 sctp_assoc_rm_peer(asoc, peer);
3127                 break;
3128         case SCTP_PARAM_SET_PRIMARY:
3129                 /* ADDIP Section 4.2.4
3130                  * If the address 0.0.0.0 or ::0 is provided, the receiver
3131                  * MAY mark the source address of the packet as its
3132                  * primary.
3133                  */
3134                 if (af->is_any(&addr))
3135                         memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));
3136 
3137                 peer = sctp_assoc_lookup_paddr(asoc, &addr);
3138                 if (!peer)
3139                         return SCTP_ERROR_DNS_FAILED;
3140 
3141                 sctp_assoc_set_primary(asoc, peer);
3142                 break;
3143         }
3144 
3145         return SCTP_ERROR_NO_ERROR;
3146 }
3147 
3148 /* Verify the ASCONF packet before we process it. */
3149 bool sctp_verify_asconf(const struct sctp_association *asoc,
3150                         struct sctp_chunk *chunk, bool addr_param_needed,
3151                         struct sctp_paramhdr **errp)
3152 {
3153         sctp_addip_chunk_t *addip = (sctp_addip_chunk_t *) chunk->chunk_hdr;
3154         union sctp_params param;
3155         bool addr_param_seen = false;
3156 
3157         sctp_walk_params(param, addip, addip_hdr.params) {
3158                 size_t length = ntohs(param.p->length);
3159 
3160                 *errp = param.p;
3161                 switch (param.p->type) {
3162                 case SCTP_PARAM_ERR_CAUSE:
3163                         break;
3164                 case SCTP_PARAM_IPV4_ADDRESS:
3165                         if (length != sizeof(sctp_ipv4addr_param_t))
3166                                 return false;
3167                         /* ensure there is only one addr param and it's in the
3168                          * beginning of addip_hdr params, or we reject it.
3169                          */
3170                         if (param.v != addip->addip_hdr.params)
3171                                 return false;
3172                         addr_param_seen = true;
3173                         break;
3174                 case SCTP_PARAM_IPV6_ADDRESS:
3175                         if (length != sizeof(sctp_ipv6addr_param_t))
3176                                 return false;
3177                         if (param.v != addip->addip_hdr.params)
3178                                 return false;
3179                         addr_param_seen = true;
3180                         break;
3181                 case SCTP_PARAM_ADD_IP:
3182                 case SCTP_PARAM_DEL_IP:
3183                 case SCTP_PARAM_SET_PRIMARY:
3184                         /* In ASCONF chunks, these need to be first. */
3185                         if (addr_param_needed && !addr_param_seen)
3186                                 return false;
3187                         length = ntohs(param.addip->param_hdr.length);
3188                         if (length < sizeof(sctp_addip_param_t) +
3189                                      sizeof(sctp_paramhdr_t))
3190                                 return false;
3191                         break;
3192                 case SCTP_PARAM_SUCCESS_REPORT:
3193                 case SCTP_PARAM_ADAPTATION_LAYER_IND:
3194                         if (length != sizeof(sctp_addip_param_t))
3195                                 return false;
3196                         break;
3197                 default:
3198                         /* This is unkown to us, reject! */
3199                         return false;
3200                 }
3201         }
3202 
3203         /* Remaining sanity checks. */
3204         if (addr_param_needed && !addr_param_seen)
3205                 return false;
3206         if (!addr_param_needed && addr_param_seen)
3207                 return false;
3208         if (param.v != chunk->chunk_end)
3209                 return false;
3210 
3211         return true;
3212 }
3213 
3214 /* Process an incoming ASCONF chunk with the next expected serial no. and
3215  * return an ASCONF_ACK chunk to be sent in response.
3216  */
3217 struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
3218                                        struct sctp_chunk *asconf)
3219 {
3220         sctp_addip_chunk_t *addip = (sctp_addip_chunk_t *) asconf->chunk_hdr;
3221         bool all_param_pass = true;
3222         union sctp_params param;
3223         sctp_addiphdr_t         *hdr;
3224         union sctp_addr_param   *addr_param;
3225         sctp_addip_param_t      *asconf_param;
3226         struct sctp_chunk       *asconf_ack;
3227         __be16  err_code;
3228         int     length = 0;
3229         int     chunk_len;
3230         __u32   serial;
3231 
3232         chunk_len = ntohs(asconf->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
3233         hdr = (sctp_addiphdr_t *)asconf->skb->data;
3234         serial = ntohl(hdr->serial);
3235 
3236         /* Skip the addiphdr and store a pointer to address parameter.  */
3237         length = sizeof(sctp_addiphdr_t);
3238         addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3239         chunk_len -= length;
3240 
3241         /* Skip the address parameter and store a pointer to the first
3242          * asconf parameter.
3243          */
3244         length = ntohs(addr_param->p.length);
3245         asconf_param = (void *)addr_param + length;
3246         chunk_len -= length;
3247 
3248         /* create an ASCONF_ACK chunk.
3249          * Based on the definitions of parameters, we know that the size of
3250          * ASCONF_ACK parameters are less than or equal to the fourfold of ASCONF
3251          * parameters.
3252          */
3253         asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 4);
3254         if (!asconf_ack)
3255                 goto done;
3256 
3257         /* Process the TLVs contained within the ASCONF chunk. */
3258         sctp_walk_params(param, addip, addip_hdr.params) {
3259                 /* Skip preceeding address parameters. */
3260                 if (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
3261                     param.p->type == SCTP_PARAM_IPV6_ADDRESS)
3262                         continue;
3263 
3264                 err_code = sctp_process_asconf_param(asoc, asconf,
3265                                                      param.addip);
3266                 /* ADDIP 4.1 A7)
3267                  * If an error response is received for a TLV parameter,
3268                  * all TLVs with no response before the failed TLV are
3269                  * considered successful if not reported.  All TLVs after
3270                  * the failed response are considered unsuccessful unless
3271                  * a specific success indication is present for the parameter.
3272                  */
3273                 if (err_code != SCTP_ERROR_NO_ERROR)
3274                         all_param_pass = false;
3275                 if (!all_param_pass)
3276                         sctp_add_asconf_response(asconf_ack, param.addip->crr_id,
3277                                                  err_code, param.addip);
3278 
3279                 /* ADDIP 4.3 D11) When an endpoint receiving an ASCONF to add
3280                  * an IP address sends an 'Out of Resource' in its response, it
3281                  * MUST also fail any subsequent add or delete requests bundled
3282                  * in the ASCONF.
3283                  */
3284                 if (err_code == SCTP_ERROR_RSRC_LOW)
3285                         goto done;
3286         }
3287 done:
3288         asoc->peer.addip_serial++;
3289 
3290         /* If we are sending a new ASCONF_ACK hold a reference to it in assoc
3291          * after freeing the reference to old asconf ack if any.
3292          */
3293         if (asconf_ack) {
3294                 sctp_chunk_hold(asconf_ack);
3295                 list_add_tail(&asconf_ack->transmitted_list,
3296                               &asoc->asconf_ack_list);
3297         }
3298 
3299         return asconf_ack;
3300 }
3301 
3302 /* Process a asconf parameter that is successfully acked. */
3303 static void sctp_asconf_param_success(struct sctp_association *asoc,
3304                                      sctp_addip_param_t *asconf_param)
3305 {
3306         struct sctp_af *af;
3307         union sctp_addr addr;
3308         struct sctp_bind_addr *bp = &asoc->base.bind_addr;
3309         union sctp_addr_param *addr_param;
3310         struct sctp_transport *transport;
3311         struct sctp_sockaddr_entry *saddr;
3312 
3313         addr_param = (void *)asconf_param + sizeof(sctp_addip_param_t);
3314 
3315         /* We have checked the packet before, so we do not check again. */
3316         af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3317         af->from_addr_param(&addr, addr_param, htons(bp->port), 0);
3318 
3319         switch (asconf_param->param_hdr.type) {
3320         case SCTP_PARAM_ADD_IP:
3321                 /* This is always done in BH context with a socket lock
3322                  * held, so the list can not change.
3323                  */
3324                 local_bh_disable();
3325                 list_for_each_entry(saddr, &bp->address_list, list) {
3326                         if (sctp_cmp_addr_exact(&saddr->a, &addr))
3327                                 saddr->state = SCTP_ADDR_SRC;
3328                 }
3329                 local_bh_enable();
3330                 list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3331                                 transports) {
3332                         dst_release(transport->dst);
3333                         transport->dst = NULL;
3334                 }
3335                 break;
3336         case SCTP_PARAM_DEL_IP:
3337                 local_bh_disable();
3338                 sctp_del_bind_addr(bp, &addr);
3339                 if (asoc->asconf_addr_del_pending != NULL &&
3340                     sctp_cmp_addr_exact(asoc->asconf_addr_del_pending, &addr)) {
3341                         kfree(asoc->asconf_addr_del_pending);
3342                         asoc->asconf_addr_del_pending = NULL;
3343                 }
3344                 local_bh_enable();
3345                 list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3346                                 transports) {
3347                         dst_release(transport->dst);
3348                         transport->dst = NULL;
3349                 }
3350                 break;
3351         default:
3352                 break;
3353         }
3354 }
3355 
3356 /* Get the corresponding ASCONF response error code from the ASCONF_ACK chunk
3357  * for the given asconf parameter.  If there is no response for this parameter,
3358  * return the error code based on the third argument 'no_err'.
3359  * ADDIP 4.1
3360  * A7) If an error response is received for a TLV parameter, all TLVs with no
3361  * response before the failed TLV are considered successful if not reported.
3362  * All TLVs after the failed response are considered unsuccessful unless a
3363  * specific success indication is present for the parameter.
3364  */
3365 static __be16 sctp_get_asconf_response(struct sctp_chunk *asconf_ack,
3366                                       sctp_addip_param_t *asconf_param,
3367                                       int no_err)
3368 {
3369         sctp_addip_param_t      *asconf_ack_param;
3370         sctp_errhdr_t           *err_param;
3371         int                     length;
3372         int                     asconf_ack_len;
3373         __be16                  err_code;
3374 
3375         if (no_err)
3376                 err_code = SCTP_ERROR_NO_ERROR;
3377         else
3378                 err_code = SCTP_ERROR_REQ_REFUSED;
3379 
3380         asconf_ack_len = ntohs(asconf_ack->chunk_hdr->length) -
3381                              sizeof(sctp_chunkhdr_t);
3382 
3383         /* Skip the addiphdr from the asconf_ack chunk and store a pointer to
3384          * the first asconf_ack parameter.
3385          */
3386         length = sizeof(sctp_addiphdr_t);
3387         asconf_ack_param = (sctp_addip_param_t *)(asconf_ack->skb->data +
3388                                                   length);
3389         asconf_ack_len -= length;
3390 
3391         while (asconf_ack_len > 0) {
3392                 if (asconf_ack_param->crr_id == asconf_param->crr_id) {
3393                         switch (asconf_ack_param->param_hdr.type) {
3394                         case SCTP_PARAM_SUCCESS_REPORT:
3395                                 return SCTP_ERROR_NO_ERROR;
3396                         case SCTP_PARAM_ERR_CAUSE:
3397                                 length = sizeof(sctp_addip_param_t);
3398                                 err_param = (void *)asconf_ack_param + length;
3399                                 asconf_ack_len -= length;
3400                                 if (asconf_ack_len > 0)
3401                                         return err_param->cause;
3402                                 else
3403                                         return SCTP_ERROR_INV_PARAM;
3404                                 break;
3405                         default:
3406                                 return SCTP_ERROR_INV_PARAM;
3407                         }
3408                 }
3409 
3410                 length = ntohs(asconf_ack_param->param_hdr.length);
3411                 asconf_ack_param = (void *)asconf_ack_param + length;
3412                 asconf_ack_len -= length;
3413         }
3414 
3415         return err_code;
3416 }
3417 
3418 /* Process an incoming ASCONF_ACK chunk against the cached last ASCONF chunk. */
3419 int sctp_process_asconf_ack(struct sctp_association *asoc,
3420                             struct sctp_chunk *asconf_ack)
3421 {
3422         struct sctp_chunk       *asconf = asoc->addip_last_asconf;
3423         union sctp_addr_param   *addr_param;
3424         sctp_addip_param_t      *asconf_param;
3425         int     length = 0;
3426         int     asconf_len = asconf->skb->len;
3427         int     all_param_pass = 0;
3428         int     no_err = 1;
3429         int     retval = 0;
3430         __be16  err_code = SCTP_ERROR_NO_ERROR;
3431 
3432         /* Skip the chunkhdr and addiphdr from the last asconf sent and store
3433          * a pointer to address parameter.
3434          */
3435         length = sizeof(sctp_addip_chunk_t);
3436         addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3437         asconf_len -= length;
3438 
3439         /* Skip the address parameter in the last asconf sent and store a
3440          * pointer to the first asconf parameter.
3441          */
3442         length = ntohs(addr_param->p.length);
3443         asconf_param = (void *)addr_param + length;
3444         asconf_len -= length;
3445 
3446         /* ADDIP 4.1
3447          * A8) If there is no response(s) to specific TLV parameter(s), and no
3448          * failures are indicated, then all request(s) are considered
3449          * successful.
3450          */
3451         if (asconf_ack->skb->len == sizeof(sctp_addiphdr_t))
3452                 all_param_pass = 1;
3453 
3454         /* Process the TLVs contained in the last sent ASCONF chunk. */
3455         while (asconf_len > 0) {
3456                 if (all_param_pass)
3457                         err_code = SCTP_ERROR_NO_ERROR;
3458                 else {
3459                         err_code = sctp_get_asconf_response(asconf_ack,
3460                                                             asconf_param,
3461                                                             no_err);
3462                         if (no_err && (SCTP_ERROR_NO_ERROR != err_code))
3463                                 no_err = 0;
3464                 }
3465 
3466                 switch (err_code) {
3467                 case SCTP_ERROR_NO_ERROR:
3468                         sctp_asconf_param_success(asoc, asconf_param);
3469                         break;
3470 
3471                 case SCTP_ERROR_RSRC_LOW:
3472                         retval = 1;
3473                         break;
3474 
3475                 case SCTP_ERROR_UNKNOWN_PARAM:
3476                         /* Disable sending this type of asconf parameter in
3477                          * future.
3478                          */
3479                         asoc->peer.addip_disabled_mask |=
3480                                 asconf_param->param_hdr.type;
3481                         break;
3482 
3483                 case SCTP_ERROR_REQ_REFUSED:
3484                 case SCTP_ERROR_DEL_LAST_IP:
3485                 case SCTP_ERROR_DEL_SRC_IP:
3486                 default:
3487                          break;
3488                 }
3489 
3490                 /* Skip the processed asconf parameter and move to the next
3491                  * one.
3492                  */
3493                 length = ntohs(asconf_param->param_hdr.length);
3494                 asconf_param = (void *)asconf_param + length;
3495                 asconf_len -= length;
3496         }
3497 
3498         if (no_err && asoc->src_out_of_asoc_ok) {
3499                 asoc->src_out_of_asoc_ok = 0;
3500                 sctp_transport_immediate_rtx(asoc->peer.primary_path);
3501         }
3502 
3503         /* Free the cached last sent asconf chunk. */
3504         list_del_init(&asconf->transmitted_list);
3505         sctp_chunk_free(asconf);
3506         asoc->addip_last_asconf = NULL;
3507 
3508         return retval;
3509 }
3510 
3511 /* Make a FWD TSN chunk. */
3512 struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
3513                                     __u32 new_cum_tsn, size_t nstreams,
3514                                     struct sctp_fwdtsn_skip *skiplist)
3515 {
3516         struct sctp_chunk *retval = NULL;
3517         struct sctp_fwdtsn_hdr ftsn_hdr;
3518         struct sctp_fwdtsn_skip skip;
3519         size_t hint;
3520         int i;
3521 
3522         hint = (nstreams + 1) * sizeof(__u32);
3523 
3524         retval = sctp_make_control(asoc, SCTP_CID_FWD_TSN, 0, hint, GFP_ATOMIC);
3525 
3526         if (!retval)
3527                 return NULL;
3528 
3529         ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
3530         retval->subh.fwdtsn_hdr =
3531                 sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
3532 
3533         for (i = 0; i < nstreams; i++) {
3534                 skip.stream = skiplist[i].stream;
3535                 skip.ssn = skiplist[i].ssn;
3536                 sctp_addto_chunk(retval, sizeof(skip), &skip);
3537         }
3538 
3539         return retval;
3540 }
3541 

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