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

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  1 /* SCTP kernel implementation
  2  * (C) Copyright IBM Corp. 2001, 2004
  3  * Copyright (c) 1999-2000 Cisco, Inc.
  4  * Copyright (c) 1999-2001 Motorola, Inc.
  5  * Copyright (c) 2001-2002 Intel Corp.
  6  *
  7  * This file is part of the SCTP kernel implementation
  8  *
  9  * These functions work with the state functions in sctp_sm_statefuns.c
 10  * to implement the state operations.  These functions implement the
 11  * steps which require modifying existing data structures.
 12  *
 13  * This SCTP implementation is free software;
 14  * you can redistribute it and/or modify it under the terms of
 15  * the GNU General Public License as published by
 16  * the Free Software Foundation; either version 2, or (at your option)
 17  * any later version.
 18  *
 19  * This SCTP implementation is distributed in the hope that it
 20  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
 21  *                 ************************
 22  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 23  * See the GNU General Public License for more details.
 24  *
 25  * You should have received a copy of the GNU General Public License
 26  * along with GNU CC; see the file COPYING.  If not, write to
 27  * the Free Software Foundation, 59 Temple Place - Suite 330,
 28  * Boston, MA 02111-1307, USA.
 29  *
 30  * Please send any bug reports or fixes you make to the
 31  * email address(es):
 32  *    lksctp developers <lksctp-developers@lists.sourceforge.net>
 33  *
 34  * Or submit a bug report through the following website:
 35  *    http://www.sf.net/projects/lksctp
 36  *
 37  * Written or modified by:
 38  *    La Monte H.P. Yarroll <piggy@acm.org>
 39  *    Karl Knutson          <karl@athena.chicago.il.us>
 40  *    C. Robin              <chris@hundredacre.ac.uk>
 41  *    Jon Grimm             <jgrimm@us.ibm.com>
 42  *    Xingang Guo           <xingang.guo@intel.com>
 43  *    Dajiang Zhang         <dajiang.zhang@nokia.com>
 44  *    Sridhar Samudrala     <sri@us.ibm.com>
 45  *    Daisy Chang           <daisyc@us.ibm.com>
 46  *    Ardelle Fan           <ardelle.fan@intel.com>
 47  *    Kevin Gao             <kevin.gao@intel.com>
 48  *
 49  * Any bugs reported given to us we will try to fix... any fixes shared will
 50  * be incorporated into the next SCTP release.
 51  */
 52 
 53 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 54 
 55 #include <linux/types.h>
 56 #include <linux/kernel.h>
 57 #include <linux/ip.h>
 58 #include <linux/ipv6.h>
 59 #include <linux/net.h>
 60 #include <linux/inet.h>
 61 #include <linux/scatterlist.h>
 62 #include <linux/crypto.h>
 63 #include <linux/slab.h>
 64 #include <net/sock.h>
 65 
 66 #include <linux/skbuff.h>
 67 #include <linux/random.h>       /* for get_random_bytes */
 68 #include <net/sctp/sctp.h>
 69 #include <net/sctp/sm.h>
 70 
 71 static struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc,
 72                                           __u8 type, __u8 flags, int paylen);
 73 static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
 74                                         const struct sctp_association *asoc,
 75                                         const struct sctp_chunk *init_chunk,
 76                                         int *cookie_len,
 77                                         const __u8 *raw_addrs, int addrs_len);
 78 static int sctp_process_param(struct sctp_association *asoc,
 79                               union sctp_params param,
 80                               const union sctp_addr *peer_addr,
 81                               gfp_t gfp);
 82 static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
 83                               const void *data);
 84 
 85 /* What was the inbound interface for this chunk? */
 86 int sctp_chunk_iif(const struct sctp_chunk *chunk)
 87 {
 88         struct sctp_af *af;
 89         int iif = 0;
 90 
 91         af = sctp_get_af_specific(ipver2af(ip_hdr(chunk->skb)->version));
 92         if (af)
 93                 iif = af->skb_iif(chunk->skb);
 94 
 95         return iif;
 96 }
 97 
 98 /* RFC 2960 3.3.2 Initiation (INIT) (1)
 99  *
100  * Note 2: The ECN capable field is reserved for future use of
101  * Explicit Congestion Notification.
102  */
103 static const struct sctp_paramhdr ecap_param = {
104         SCTP_PARAM_ECN_CAPABLE,
105         cpu_to_be16(sizeof(struct sctp_paramhdr)),
106 };
107 static const struct sctp_paramhdr prsctp_param = {
108         SCTP_PARAM_FWD_TSN_SUPPORT,
109         cpu_to_be16(sizeof(struct sctp_paramhdr)),
110 };
111 
112 /* A helper to initialize an op error inside a
113  * provided chunk, as most cause codes will be embedded inside an
114  * abort chunk.
115  */
116 void  sctp_init_cause(struct sctp_chunk *chunk, __be16 cause_code,
117                       size_t paylen)
118 {
119         sctp_errhdr_t err;
120         __u16 len;
121 
122         /* Cause code constants are now defined in network order.  */
123         err.cause = cause_code;
124         len = sizeof(sctp_errhdr_t) + paylen;
125         err.length  = htons(len);
126         chunk->subh.err_hdr = sctp_addto_chunk(chunk, sizeof(sctp_errhdr_t), &err);
127 }
128 
129 /* A helper to initialize an op error inside a
130  * provided chunk, as most cause codes will be embedded inside an
131  * abort chunk.  Differs from sctp_init_cause in that it won't oops
132  * if there isn't enough space in the op error chunk
133  */
134 static int sctp_init_cause_fixed(struct sctp_chunk *chunk, __be16 cause_code,
135                       size_t paylen)
136 {
137         sctp_errhdr_t err;
138         __u16 len;
139 
140         /* Cause code constants are now defined in network order.  */
141         err.cause = cause_code;
142         len = sizeof(sctp_errhdr_t) + paylen;
143         err.length  = htons(len);
144 
145         if (skb_tailroom(chunk->skb) < len)
146                 return -ENOSPC;
147         chunk->subh.err_hdr = sctp_addto_chunk_fixed(chunk,
148                                                      sizeof(sctp_errhdr_t),
149                                                      &err);
150         return 0;
151 }
152 /* 3.3.2 Initiation (INIT) (1)
153  *
154  * This chunk is used to initiate a SCTP association between two
155  * endpoints. The format of the INIT chunk is shown below:
156  *
157  *     0                   1                   2                   3
158  *     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
159  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
160  *    |   Type = 1    |  Chunk Flags  |      Chunk Length             |
161  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
162  *    |                         Initiate Tag                          |
163  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
164  *    |           Advertised Receiver Window Credit (a_rwnd)          |
165  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
166  *    |  Number of Outbound Streams   |  Number of Inbound Streams    |
167  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
168  *    |                          Initial TSN                          |
169  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
170  *    \                                                               \
171  *    /              Optional/Variable-Length Parameters              /
172  *    \                                                               \
173  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
174  *
175  *
176  * The INIT chunk contains the following parameters. Unless otherwise
177  * noted, each parameter MUST only be included once in the INIT chunk.
178  *
179  * Fixed Parameters                     Status
180  * ----------------------------------------------
181  * Initiate Tag                        Mandatory
182  * Advertised Receiver Window Credit   Mandatory
183  * Number of Outbound Streams          Mandatory
184  * Number of Inbound Streams           Mandatory
185  * Initial TSN                         Mandatory
186  *
187  * Variable Parameters                  Status     Type Value
188  * -------------------------------------------------------------
189  * IPv4 Address (Note 1)               Optional    5
190  * IPv6 Address (Note 1)               Optional    6
191  * Cookie Preservative                 Optional    9
192  * Reserved for ECN Capable (Note 2)   Optional    32768 (0x8000)
193  * Host Name Address (Note 3)          Optional    11
194  * Supported Address Types (Note 4)    Optional    12
195  */
196 struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc,
197                              const struct sctp_bind_addr *bp,
198                              gfp_t gfp, int vparam_len)
199 {
200         struct net *net = sock_net(asoc->base.sk);
201         sctp_inithdr_t init;
202         union sctp_params addrs;
203         size_t chunksize;
204         struct sctp_chunk *retval = NULL;
205         int num_types, addrs_len = 0;
206         struct sctp_sock *sp;
207         sctp_supported_addrs_param_t sat;
208         __be16 types[2];
209         sctp_adaptation_ind_param_t aiparam;
210         sctp_supported_ext_param_t ext_param;
211         int num_ext = 0;
212         __u8 extensions[3];
213         sctp_paramhdr_t *auth_chunks = NULL,
214                         *auth_hmacs = NULL;
215 
216         /* RFC 2960 3.3.2 Initiation (INIT) (1)
217          *
218          * Note 1: The INIT chunks can contain multiple addresses that
219          * can be IPv4 and/or IPv6 in any combination.
220          */
221         retval = NULL;
222 
223         /* Convert the provided bind address list to raw format. */
224         addrs = sctp_bind_addrs_to_raw(bp, &addrs_len, gfp);
225 
226         init.init_tag              = htonl(asoc->c.my_vtag);
227         init.a_rwnd                = htonl(asoc->rwnd);
228         init.num_outbound_streams  = htons(asoc->c.sinit_num_ostreams);
229         init.num_inbound_streams   = htons(asoc->c.sinit_max_instreams);
230         init.initial_tsn           = htonl(asoc->c.initial_tsn);
231 
232         /* How many address types are needed? */
233         sp = sctp_sk(asoc->base.sk);
234         num_types = sp->pf->supported_addrs(sp, types);
235 
236         chunksize = sizeof(init) + addrs_len;
237         chunksize += WORD_ROUND(SCTP_SAT_LEN(num_types));
238         chunksize += sizeof(ecap_param);
239 
240         if (net->sctp.prsctp_enable)
241                 chunksize += sizeof(prsctp_param);
242 
243         /* ADDIP: Section 4.2.7:
244          *  An implementation supporting this extension [ADDIP] MUST list
245          *  the ASCONF,the ASCONF-ACK, and the AUTH  chunks in its INIT and
246          *  INIT-ACK parameters.
247          */
248         if (net->sctp.addip_enable) {
249                 extensions[num_ext] = SCTP_CID_ASCONF;
250                 extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
251                 num_ext += 2;
252         }
253 
254         if (sp->adaptation_ind)
255                 chunksize += sizeof(aiparam);
256 
257         chunksize += vparam_len;
258 
259         /* Account for AUTH related parameters */
260         if (net->sctp.auth_enable) {
261                 /* Add random parameter length*/
262                 chunksize += sizeof(asoc->c.auth_random);
263 
264                 /* Add HMACS parameter length if any were defined */
265                 auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
266                 if (auth_hmacs->length)
267                         chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
268                 else
269                         auth_hmacs = NULL;
270 
271                 /* Add CHUNKS parameter length */
272                 auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
273                 if (auth_chunks->length)
274                         chunksize += WORD_ROUND(ntohs(auth_chunks->length));
275                 else
276                         auth_chunks = NULL;
277 
278                 extensions[num_ext] = SCTP_CID_AUTH;
279                 num_ext += 1;
280         }
281 
282         /* If we have any extensions to report, account for that */
283         if (num_ext)
284                 chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) +
285                                         num_ext);
286 
287         /* RFC 2960 3.3.2 Initiation (INIT) (1)
288          *
289          * Note 3: An INIT chunk MUST NOT contain more than one Host
290          * Name address parameter. Moreover, the sender of the INIT
291          * MUST NOT combine any other address types with the Host Name
292          * address in the INIT. The receiver of INIT MUST ignore any
293          * other address types if the Host Name address parameter is
294          * present in the received INIT chunk.
295          *
296          * PLEASE DO NOT FIXME [This version does not support Host Name.]
297          */
298 
299         retval = sctp_make_chunk(asoc, SCTP_CID_INIT, 0, chunksize);
300         if (!retval)
301                 goto nodata;
302 
303         retval->subh.init_hdr =
304                 sctp_addto_chunk(retval, sizeof(init), &init);
305         retval->param_hdr.v =
306                 sctp_addto_chunk(retval, addrs_len, addrs.v);
307 
308         /* RFC 2960 3.3.2 Initiation (INIT) (1)
309          *
310          * Note 4: This parameter, when present, specifies all the
311          * address types the sending endpoint can support. The absence
312          * of this parameter indicates that the sending endpoint can
313          * support any address type.
314          */
315         sat.param_hdr.type = SCTP_PARAM_SUPPORTED_ADDRESS_TYPES;
316         sat.param_hdr.length = htons(SCTP_SAT_LEN(num_types));
317         sctp_addto_chunk(retval, sizeof(sat), &sat);
318         sctp_addto_chunk(retval, num_types * sizeof(__u16), &types);
319 
320         sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
321 
322         /* Add the supported extensions parameter.  Be nice and add this
323          * fist before addiding the parameters for the extensions themselves
324          */
325         if (num_ext) {
326                 ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
327                 ext_param.param_hdr.length =
328                             htons(sizeof(sctp_supported_ext_param_t) + num_ext);
329                 sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
330                                 &ext_param);
331                 sctp_addto_param(retval, num_ext, extensions);
332         }
333 
334         if (net->sctp.prsctp_enable)
335                 sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
336 
337         if (sp->adaptation_ind) {
338                 aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
339                 aiparam.param_hdr.length = htons(sizeof(aiparam));
340                 aiparam.adaptation_ind = htonl(sp->adaptation_ind);
341                 sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
342         }
343 
344         /* Add SCTP-AUTH chunks to the parameter list */
345         if (net->sctp.auth_enable) {
346                 sctp_addto_chunk(retval, sizeof(asoc->c.auth_random),
347                                  asoc->c.auth_random);
348                 if (auth_hmacs)
349                         sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
350                                         auth_hmacs);
351                 if (auth_chunks)
352                         sctp_addto_chunk(retval, ntohs(auth_chunks->length),
353                                         auth_chunks);
354         }
355 nodata:
356         kfree(addrs.v);
357         return retval;
358 }
359 
360 struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc,
361                                  const struct sctp_chunk *chunk,
362                                  gfp_t gfp, int unkparam_len)
363 {
364         sctp_inithdr_t initack;
365         struct sctp_chunk *retval;
366         union sctp_params addrs;
367         struct sctp_sock *sp;
368         int addrs_len;
369         sctp_cookie_param_t *cookie;
370         int cookie_len;
371         size_t chunksize;
372         sctp_adaptation_ind_param_t aiparam;
373         sctp_supported_ext_param_t ext_param;
374         int num_ext = 0;
375         __u8 extensions[3];
376         sctp_paramhdr_t *auth_chunks = NULL,
377                         *auth_hmacs = NULL,
378                         *auth_random = NULL;
379 
380         retval = NULL;
381 
382         /* Note: there may be no addresses to embed. */
383         addrs = sctp_bind_addrs_to_raw(&asoc->base.bind_addr, &addrs_len, gfp);
384 
385         initack.init_tag                = htonl(asoc->c.my_vtag);
386         initack.a_rwnd                  = htonl(asoc->rwnd);
387         initack.num_outbound_streams    = htons(asoc->c.sinit_num_ostreams);
388         initack.num_inbound_streams     = htons(asoc->c.sinit_max_instreams);
389         initack.initial_tsn             = htonl(asoc->c.initial_tsn);
390 
391         /* FIXME:  We really ought to build the cookie right
392          * into the packet instead of allocating more fresh memory.
393          */
394         cookie = sctp_pack_cookie(asoc->ep, asoc, chunk, &cookie_len,
395                                   addrs.v, addrs_len);
396         if (!cookie)
397                 goto nomem_cookie;
398 
399         /* Calculate the total size of allocation, include the reserved
400          * space for reporting unknown parameters if it is specified.
401          */
402         sp = sctp_sk(asoc->base.sk);
403         chunksize = sizeof(initack) + addrs_len + cookie_len + unkparam_len;
404 
405         /* Tell peer that we'll do ECN only if peer advertised such cap.  */
406         if (asoc->peer.ecn_capable)
407                 chunksize += sizeof(ecap_param);
408 
409         if (asoc->peer.prsctp_capable)
410                 chunksize += sizeof(prsctp_param);
411 
412         if (asoc->peer.asconf_capable) {
413                 extensions[num_ext] = SCTP_CID_ASCONF;
414                 extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
415                 num_ext += 2;
416         }
417 
418         if (sp->adaptation_ind)
419                 chunksize += sizeof(aiparam);
420 
421         if (asoc->peer.auth_capable) {
422                 auth_random = (sctp_paramhdr_t *)asoc->c.auth_random;
423                 chunksize += ntohs(auth_random->length);
424 
425                 auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
426                 if (auth_hmacs->length)
427                         chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
428                 else
429                         auth_hmacs = NULL;
430 
431                 auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
432                 if (auth_chunks->length)
433                         chunksize += WORD_ROUND(ntohs(auth_chunks->length));
434                 else
435                         auth_chunks = NULL;
436 
437                 extensions[num_ext] = SCTP_CID_AUTH;
438                 num_ext += 1;
439         }
440 
441         if (num_ext)
442                 chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) +
443                                         num_ext);
444 
445         /* Now allocate and fill out the chunk.  */
446         retval = sctp_make_chunk(asoc, SCTP_CID_INIT_ACK, 0, chunksize);
447         if (!retval)
448                 goto nomem_chunk;
449 
450         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
451          *
452          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
453          * HEARTBEAT ACK, * etc.) to the same destination transport
454          * address from which it received the DATA or control chunk
455          * to which it is replying.
456          *
457          * [INIT ACK back to where the INIT came from.]
458          */
459         retval->transport = chunk->transport;
460 
461         retval->subh.init_hdr =
462                 sctp_addto_chunk(retval, sizeof(initack), &initack);
463         retval->param_hdr.v = sctp_addto_chunk(retval, addrs_len, addrs.v);
464         sctp_addto_chunk(retval, cookie_len, cookie);
465         if (asoc->peer.ecn_capable)
466                 sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
467         if (num_ext) {
468                 ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
469                 ext_param.param_hdr.length =
470                             htons(sizeof(sctp_supported_ext_param_t) + num_ext);
471                 sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
472                                  &ext_param);
473                 sctp_addto_param(retval, num_ext, extensions);
474         }
475         if (asoc->peer.prsctp_capable)
476                 sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
477 
478         if (sp->adaptation_ind) {
479                 aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
480                 aiparam.param_hdr.length = htons(sizeof(aiparam));
481                 aiparam.adaptation_ind = htonl(sp->adaptation_ind);
482                 sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
483         }
484 
485         if (asoc->peer.auth_capable) {
486                 sctp_addto_chunk(retval, ntohs(auth_random->length),
487                                  auth_random);
488                 if (auth_hmacs)
489                         sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
490                                         auth_hmacs);
491                 if (auth_chunks)
492                         sctp_addto_chunk(retval, ntohs(auth_chunks->length),
493                                         auth_chunks);
494         }
495 
496         /* We need to remove the const qualifier at this point.  */
497         retval->asoc = (struct sctp_association *) asoc;
498 
499 nomem_chunk:
500         kfree(cookie);
501 nomem_cookie:
502         kfree(addrs.v);
503         return retval;
504 }
505 
506 /* 3.3.11 Cookie Echo (COOKIE ECHO) (10):
507  *
508  * This chunk is used only during the initialization of an association.
509  * It is sent by the initiator of an association to its peer to complete
510  * the initialization process. This chunk MUST precede any DATA chunk
511  * sent within the association, but MAY be bundled with one or more DATA
512  * chunks in the same packet.
513  *
514  *      0                   1                   2                   3
515  *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
516  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
517  *     |   Type = 10   |Chunk  Flags   |         Length                |
518  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
519  *     /                     Cookie                                    /
520  *     \                                                               \
521  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
522  *
523  * Chunk Flags: 8 bit
524  *
525  *   Set to zero on transmit and ignored on receipt.
526  *
527  * Length: 16 bits (unsigned integer)
528  *
529  *   Set to the size of the chunk in bytes, including the 4 bytes of
530  *   the chunk header and the size of the Cookie.
531  *
532  * Cookie: variable size
533  *
534  *   This field must contain the exact cookie received in the
535  *   State Cookie parameter from the previous INIT ACK.
536  *
537  *   An implementation SHOULD make the cookie as small as possible
538  *   to insure interoperability.
539  */
540 struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *asoc,
541                                     const struct sctp_chunk *chunk)
542 {
543         struct sctp_chunk *retval;
544         void *cookie;
545         int cookie_len;
546 
547         cookie = asoc->peer.cookie;
548         cookie_len = asoc->peer.cookie_len;
549 
550         /* Build a cookie echo chunk.  */
551         retval = sctp_make_chunk(asoc, SCTP_CID_COOKIE_ECHO, 0, cookie_len);
552         if (!retval)
553                 goto nodata;
554         retval->subh.cookie_hdr =
555                 sctp_addto_chunk(retval, cookie_len, cookie);
556 
557         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
558          *
559          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
560          * HEARTBEAT ACK, * etc.) to the same destination transport
561          * address from which it * received the DATA or control chunk
562          * to which it is replying.
563          *
564          * [COOKIE ECHO back to where the INIT ACK came from.]
565          */
566         if (chunk)
567                 retval->transport = chunk->transport;
568 
569 nodata:
570         return retval;
571 }
572 
573 /* 3.3.12 Cookie Acknowledgement (COOKIE ACK) (11):
574  *
575  * This chunk is used only during the initialization of an
576  * association.  It is used to acknowledge the receipt of a COOKIE
577  * ECHO chunk.  This chunk MUST precede any DATA or SACK chunk sent
578  * within the association, but MAY be bundled with one or more DATA
579  * chunks or SACK chunk in the same SCTP packet.
580  *
581  *      0                   1                   2                   3
582  *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
583  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
584  *     |   Type = 11   |Chunk  Flags   |     Length = 4                |
585  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
586  *
587  * Chunk Flags: 8 bits
588  *
589  *   Set to zero on transmit and ignored on receipt.
590  */
591 struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *asoc,
592                                    const struct sctp_chunk *chunk)
593 {
594         struct sctp_chunk *retval;
595 
596         retval = sctp_make_chunk(asoc, SCTP_CID_COOKIE_ACK, 0, 0);
597 
598         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
599          *
600          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
601          * HEARTBEAT ACK, * etc.) to the same destination transport
602          * address from which it * received the DATA or control chunk
603          * to which it is replying.
604          *
605          * [COOKIE ACK back to where the COOKIE ECHO came from.]
606          */
607         if (retval && chunk)
608                 retval->transport = chunk->transport;
609 
610         return retval;
611 }
612 
613 /*
614  *  Appendix A: Explicit Congestion Notification:
615  *  CWR:
616  *
617  *  RFC 2481 details a specific bit for a sender to send in the header of
618  *  its next outbound TCP segment to indicate to its peer that it has
619  *  reduced its congestion window.  This is termed the CWR bit.  For
620  *  SCTP the same indication is made by including the CWR chunk.
621  *  This chunk contains one data element, i.e. the TSN number that
622  *  was sent in the ECNE chunk.  This element represents the lowest
623  *  TSN number in the datagram that was originally marked with the
624  *  CE bit.
625  *
626  *     0                   1                   2                   3
627  *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
628  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
629  *    | Chunk Type=13 | Flags=00000000|    Chunk Length = 8           |
630  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
631  *    |                      Lowest TSN Number                        |
632  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
633  *
634  *     Note: The CWR is considered a Control chunk.
635  */
636 struct sctp_chunk *sctp_make_cwr(const struct sctp_association *asoc,
637                             const __u32 lowest_tsn,
638                             const struct sctp_chunk *chunk)
639 {
640         struct sctp_chunk *retval;
641         sctp_cwrhdr_t cwr;
642 
643         cwr.lowest_tsn = htonl(lowest_tsn);
644         retval = sctp_make_chunk(asoc, SCTP_CID_ECN_CWR, 0,
645                                  sizeof(sctp_cwrhdr_t));
646 
647         if (!retval)
648                 goto nodata;
649 
650         retval->subh.ecn_cwr_hdr =
651                 sctp_addto_chunk(retval, sizeof(cwr), &cwr);
652 
653         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
654          *
655          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
656          * HEARTBEAT ACK, * etc.) to the same destination transport
657          * address from which it * received the DATA or control chunk
658          * to which it is replying.
659          *
660          * [Report a reduced congestion window back to where the ECNE
661          * came from.]
662          */
663         if (chunk)
664                 retval->transport = chunk->transport;
665 
666 nodata:
667         return retval;
668 }
669 
670 /* Make an ECNE chunk.  This is a congestion experienced report.  */
671 struct sctp_chunk *sctp_make_ecne(const struct sctp_association *asoc,
672                              const __u32 lowest_tsn)
673 {
674         struct sctp_chunk *retval;
675         sctp_ecnehdr_t ecne;
676 
677         ecne.lowest_tsn = htonl(lowest_tsn);
678         retval = sctp_make_chunk(asoc, SCTP_CID_ECN_ECNE, 0,
679                                  sizeof(sctp_ecnehdr_t));
680         if (!retval)
681                 goto nodata;
682         retval->subh.ecne_hdr =
683                 sctp_addto_chunk(retval, sizeof(ecne), &ecne);
684 
685 nodata:
686         return retval;
687 }
688 
689 /* Make a DATA chunk for the given association from the provided
690  * parameters.  However, do not populate the data payload.
691  */
692 struct sctp_chunk *sctp_make_datafrag_empty(struct sctp_association *asoc,
693                                        const struct sctp_sndrcvinfo *sinfo,
694                                        int data_len, __u8 flags, __u16 ssn)
695 {
696         struct sctp_chunk *retval;
697         struct sctp_datahdr dp;
698         int chunk_len;
699 
700         /* We assign the TSN as LATE as possible, not here when
701          * creating the chunk.
702          */
703         dp.tsn = 0;
704         dp.stream = htons(sinfo->sinfo_stream);
705         dp.ppid   = sinfo->sinfo_ppid;
706 
707         /* Set the flags for an unordered send.  */
708         if (sinfo->sinfo_flags & SCTP_UNORDERED) {
709                 flags |= SCTP_DATA_UNORDERED;
710                 dp.ssn = 0;
711         } else
712                 dp.ssn = htons(ssn);
713 
714         chunk_len = sizeof(dp) + data_len;
715         retval = sctp_make_chunk(asoc, SCTP_CID_DATA, flags, chunk_len);
716         if (!retval)
717                 goto nodata;
718 
719         retval->subh.data_hdr = sctp_addto_chunk(retval, sizeof(dp), &dp);
720         memcpy(&retval->sinfo, sinfo, sizeof(struct sctp_sndrcvinfo));
721 
722 nodata:
723         return retval;
724 }
725 
726 /* Create a selective ackowledgement (SACK) for the given
727  * association.  This reports on which TSN's we've seen to date,
728  * including duplicates and gaps.
729  */
730 struct sctp_chunk *sctp_make_sack(const struct sctp_association *asoc)
731 {
732         struct sctp_chunk *retval;
733         struct sctp_sackhdr sack;
734         int len;
735         __u32 ctsn;
736         __u16 num_gabs, num_dup_tsns;
737         struct sctp_association *aptr = (struct sctp_association *)asoc;
738         struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
739         struct sctp_gap_ack_block gabs[SCTP_MAX_GABS];
740         struct sctp_transport *trans;
741 
742         memset(gabs, 0, sizeof(gabs));
743         ctsn = sctp_tsnmap_get_ctsn(map);
744 
745         pr_debug("%s: sackCTSNAck sent:0x%x\n", __func__, ctsn);
746 
747         /* How much room is needed in the chunk? */
748         num_gabs = sctp_tsnmap_num_gabs(map, gabs);
749         num_dup_tsns = sctp_tsnmap_num_dups(map);
750 
751         /* Initialize the SACK header.  */
752         sack.cum_tsn_ack            = htonl(ctsn);
753         sack.a_rwnd                 = htonl(asoc->a_rwnd);
754         sack.num_gap_ack_blocks     = htons(num_gabs);
755         sack.num_dup_tsns           = htons(num_dup_tsns);
756 
757         len = sizeof(sack)
758                 + sizeof(struct sctp_gap_ack_block) * num_gabs
759                 + sizeof(__u32) * num_dup_tsns;
760 
761         /* Create the chunk.  */
762         retval = sctp_make_chunk(asoc, SCTP_CID_SACK, 0, len);
763         if (!retval)
764                 goto nodata;
765 
766         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
767          *
768          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
769          * HEARTBEAT ACK, etc.) to the same destination transport
770          * address from which it received the DATA or control chunk to
771          * which it is replying.  This rule should also be followed if
772          * the endpoint is bundling DATA chunks together with the
773          * reply chunk.
774          *
775          * However, when acknowledging multiple DATA chunks received
776          * in packets from different source addresses in a single
777          * SACK, the SACK chunk may be transmitted to one of the
778          * destination transport addresses from which the DATA or
779          * control chunks being acknowledged were received.
780          *
781          * [BUG:  We do not implement the following paragraph.
782          * Perhaps we should remember the last transport we used for a
783          * SACK and avoid that (if possible) if we have seen any
784          * duplicates. --piggy]
785          *
786          * When a receiver of a duplicate DATA chunk sends a SACK to a
787          * multi- homed endpoint it MAY be beneficial to vary the
788          * destination address and not use the source address of the
789          * DATA chunk.  The reason being that receiving a duplicate
790          * from a multi-homed endpoint might indicate that the return
791          * path (as specified in the source address of the DATA chunk)
792          * for the SACK is broken.
793          *
794          * [Send to the address from which we last received a DATA chunk.]
795          */
796         retval->transport = asoc->peer.last_data_from;
797 
798         retval->subh.sack_hdr =
799                 sctp_addto_chunk(retval, sizeof(sack), &sack);
800 
801         /* Add the gap ack block information.   */
802         if (num_gabs)
803                 sctp_addto_chunk(retval, sizeof(__u32) * num_gabs,
804                                  gabs);
805 
806         /* Add the duplicate TSN information.  */
807         if (num_dup_tsns) {
808                 aptr->stats.idupchunks += num_dup_tsns;
809                 sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns,
810                                  sctp_tsnmap_get_dups(map));
811         }
812         /* Once we have a sack generated, check to see what our sack
813          * generation is, if its 0, reset the transports to 0, and reset
814          * the association generation to 1
815          *
816          * The idea is that zero is never used as a valid generation for the
817          * association so no transport will match after a wrap event like this,
818          * Until the next sack
819          */
820         if (++aptr->peer.sack_generation == 0) {
821                 list_for_each_entry(trans, &asoc->peer.transport_addr_list,
822                                     transports)
823                         trans->sack_generation = 0;
824                 aptr->peer.sack_generation = 1;
825         }
826 nodata:
827         return retval;
828 }
829 
830 /* Make a SHUTDOWN chunk. */
831 struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
832                                       const struct sctp_chunk *chunk)
833 {
834         struct sctp_chunk *retval;
835         sctp_shutdownhdr_t shut;
836         __u32 ctsn;
837 
838         ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
839         shut.cum_tsn_ack = htonl(ctsn);
840 
841         retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN, 0,
842                                  sizeof(sctp_shutdownhdr_t));
843         if (!retval)
844                 goto nodata;
845 
846         retval->subh.shutdown_hdr =
847                 sctp_addto_chunk(retval, sizeof(shut), &shut);
848 
849         if (chunk)
850                 retval->transport = chunk->transport;
851 nodata:
852         return retval;
853 }
854 
855 struct sctp_chunk *sctp_make_shutdown_ack(const struct sctp_association *asoc,
856                                      const struct sctp_chunk *chunk)
857 {
858         struct sctp_chunk *retval;
859 
860         retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN_ACK, 0, 0);
861 
862         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
863          *
864          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
865          * HEARTBEAT ACK, * etc.) to the same destination transport
866          * address from which it * received the DATA or control chunk
867          * to which it is replying.
868          *
869          * [ACK back to where the SHUTDOWN came from.]
870          */
871         if (retval && chunk)
872                 retval->transport = chunk->transport;
873 
874         return retval;
875 }
876 
877 struct sctp_chunk *sctp_make_shutdown_complete(
878         const struct sctp_association *asoc,
879         const struct sctp_chunk *chunk)
880 {
881         struct sctp_chunk *retval;
882         __u8 flags = 0;
883 
884         /* Set the T-bit if we have no association (vtag will be
885          * reflected)
886          */
887         flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;
888 
889         retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags, 0);
890 
891         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
892          *
893          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
894          * HEARTBEAT ACK, * etc.) to the same destination transport
895          * address from which it * received the DATA or control chunk
896          * to which it is replying.
897          *
898          * [Report SHUTDOWN COMPLETE back to where the SHUTDOWN ACK
899          * came from.]
900          */
901         if (retval && chunk)
902                 retval->transport = chunk->transport;
903 
904         return retval;
905 }
906 
907 /* Create an ABORT.  Note that we set the T bit if we have no
908  * association, except when responding to an INIT (sctpimpguide 2.41).
909  */
910 struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc,
911                               const struct sctp_chunk *chunk,
912                               const size_t hint)
913 {
914         struct sctp_chunk *retval;
915         __u8 flags = 0;
916 
917         /* Set the T-bit if we have no association and 'chunk' is not
918          * an INIT (vtag will be reflected).
919          */
920         if (!asoc) {
921                 if (chunk && chunk->chunk_hdr &&
922                     chunk->chunk_hdr->type == SCTP_CID_INIT)
923                         flags = 0;
924                 else
925                         flags = SCTP_CHUNK_FLAG_T;
926         }
927 
928         retval = sctp_make_chunk(asoc, SCTP_CID_ABORT, flags, hint);
929 
930         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
931          *
932          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
933          * HEARTBEAT ACK, * etc.) to the same destination transport
934          * address from which it * received the DATA or control chunk
935          * to which it is replying.
936          *
937          * [ABORT back to where the offender came from.]
938          */
939         if (retval && chunk)
940                 retval->transport = chunk->transport;
941 
942         return retval;
943 }
944 
945 /* Helper to create ABORT with a NO_USER_DATA error.  */
946 struct sctp_chunk *sctp_make_abort_no_data(
947         const struct sctp_association *asoc,
948         const struct sctp_chunk *chunk, __u32 tsn)
949 {
950         struct sctp_chunk *retval;
951         __be32 payload;
952 
953         retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t)
954                                  + sizeof(tsn));
955 
956         if (!retval)
957                 goto no_mem;
958 
959         /* Put the tsn back into network byte order.  */
960         payload = htonl(tsn);
961         sctp_init_cause(retval, SCTP_ERROR_NO_DATA, sizeof(payload));
962         sctp_addto_chunk(retval, sizeof(payload), (const void *)&payload);
963 
964         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
965          *
966          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
967          * HEARTBEAT ACK, * etc.) to the same destination transport
968          * address from which it * received the DATA or control chunk
969          * to which it is replying.
970          *
971          * [ABORT back to where the offender came from.]
972          */
973         if (chunk)
974                 retval->transport = chunk->transport;
975 
976 no_mem:
977         return retval;
978 }
979 
980 /* Helper to create ABORT with a SCTP_ERROR_USER_ABORT error.  */
981 struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *asoc,
982                                         const struct msghdr *msg,
983                                         size_t paylen)
984 {
985         struct sctp_chunk *retval;
986         void *payload = NULL;
987         int err;
988 
989         retval = sctp_make_abort(asoc, NULL, sizeof(sctp_errhdr_t) + paylen);
990         if (!retval)
991                 goto err_chunk;
992 
993         if (paylen) {
994                 /* Put the msg_iov together into payload.  */
995                 payload = kmalloc(paylen, GFP_KERNEL);
996                 if (!payload)
997                         goto err_payload;
998 
999                 err = memcpy_fromiovec(payload, msg->msg_iov, paylen);
1000                 if (err < 0)
1001                         goto err_copy;
1002         }
1003 
1004         sctp_init_cause(retval, SCTP_ERROR_USER_ABORT, paylen);
1005         sctp_addto_chunk(retval, paylen, payload);
1006 
1007         if (paylen)
1008                 kfree(payload);
1009 
1010         return retval;
1011 
1012 err_copy:
1013         kfree(payload);
1014 err_payload:
1015         sctp_chunk_free(retval);
1016         retval = NULL;
1017 err_chunk:
1018         return retval;
1019 }
1020 
1021 /* Append bytes to the end of a parameter.  Will panic if chunk is not big
1022  * enough.
1023  */
1024 static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
1025                               const void *data)
1026 {
1027         void *target;
1028         int chunklen = ntohs(chunk->chunk_hdr->length);
1029 
1030         target = skb_put(chunk->skb, len);
1031 
1032         if (data)
1033                 memcpy(target, data, len);
1034         else
1035                 memset(target, 0, len);
1036 
1037         /* Adjust the chunk length field.  */
1038         chunk->chunk_hdr->length = htons(chunklen + len);
1039         chunk->chunk_end = skb_tail_pointer(chunk->skb);
1040 
1041         return target;
1042 }
1043 
1044 /* Make an ABORT chunk with a PROTOCOL VIOLATION cause code. */
1045 struct sctp_chunk *sctp_make_abort_violation(
1046         const struct sctp_association *asoc,
1047         const struct sctp_chunk *chunk,
1048         const __u8   *payload,
1049         const size_t paylen)
1050 {
1051         struct sctp_chunk  *retval;
1052         struct sctp_paramhdr phdr;
1053 
1054         retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t) + paylen
1055                                         + sizeof(sctp_paramhdr_t));
1056         if (!retval)
1057                 goto end;
1058 
1059         sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, paylen
1060                                         + sizeof(sctp_paramhdr_t));
1061 
1062         phdr.type = htons(chunk->chunk_hdr->type);
1063         phdr.length = chunk->chunk_hdr->length;
1064         sctp_addto_chunk(retval, paylen, payload);
1065         sctp_addto_param(retval, sizeof(sctp_paramhdr_t), &phdr);
1066 
1067 end:
1068         return retval;
1069 }
1070 
1071 struct sctp_chunk *sctp_make_violation_paramlen(
1072         const struct sctp_association *asoc,
1073         const struct sctp_chunk *chunk,
1074         struct sctp_paramhdr *param)
1075 {
1076         struct sctp_chunk *retval;
1077         static const char error[] = "The following parameter had invalid length:";
1078         size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t) +
1079                                 sizeof(sctp_paramhdr_t);
1080 
1081         retval = sctp_make_abort(asoc, chunk, payload_len);
1082         if (!retval)
1083                 goto nodata;
1084 
1085         sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION,
1086                         sizeof(error) + sizeof(sctp_paramhdr_t));
1087         sctp_addto_chunk(retval, sizeof(error), error);
1088         sctp_addto_param(retval, sizeof(sctp_paramhdr_t), param);
1089 
1090 nodata:
1091         return retval;
1092 }
1093 
1094 struct sctp_chunk *sctp_make_violation_max_retrans(
1095         const struct sctp_association *asoc,
1096         const struct sctp_chunk *chunk)
1097 {
1098         struct sctp_chunk *retval;
1099         static const char error[] = "Association exceeded its max_retans count";
1100         size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t);
1101 
1102         retval = sctp_make_abort(asoc, chunk, payload_len);
1103         if (!retval)
1104                 goto nodata;
1105 
1106         sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, sizeof(error));
1107         sctp_addto_chunk(retval, sizeof(error), error);
1108 
1109 nodata:
1110         return retval;
1111 }
1112 
1113 /* Make a HEARTBEAT chunk.  */
1114 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
1115                                   const struct sctp_transport *transport)
1116 {
1117         struct sctp_chunk *retval;
1118         sctp_sender_hb_info_t hbinfo;
1119 
1120         retval = sctp_make_chunk(asoc, SCTP_CID_HEARTBEAT, 0, sizeof(hbinfo));
1121 
1122         if (!retval)
1123                 goto nodata;
1124 
1125         hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO;
1126         hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t));
1127         hbinfo.daddr = transport->ipaddr;
1128         hbinfo.sent_at = jiffies;
1129         hbinfo.hb_nonce = transport->hb_nonce;
1130 
1131         /* Cast away the 'const', as this is just telling the chunk
1132          * what transport it belongs to.
1133          */
1134         retval->transport = (struct sctp_transport *) transport;
1135         retval->subh.hbs_hdr = sctp_addto_chunk(retval, sizeof(hbinfo),
1136                                                 &hbinfo);
1137 
1138 nodata:
1139         return retval;
1140 }
1141 
1142 struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc,
1143                                       const struct sctp_chunk *chunk,
1144                                       const void *payload, const size_t paylen)
1145 {
1146         struct sctp_chunk *retval;
1147 
1148         retval  = sctp_make_chunk(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen);
1149         if (!retval)
1150                 goto nodata;
1151 
1152         retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);
1153 
1154         /* RFC 2960 6.4 Multi-homed SCTP Endpoints
1155          *
1156          * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1157          * HEARTBEAT ACK, * etc.) to the same destination transport
1158          * address from which it * received the DATA or control chunk
1159          * to which it is replying.
1160          *
1161          * [HBACK back to where the HEARTBEAT came from.]
1162          */
1163         if (chunk)
1164                 retval->transport = chunk->transport;
1165 
1166 nodata:
1167         return retval;
1168 }
1169 
1170 /* Create an Operation Error chunk with the specified space reserved.
1171  * This routine can be used for containing multiple causes in the chunk.
1172  */
1173 static struct sctp_chunk *sctp_make_op_error_space(
1174         const struct sctp_association *asoc,
1175         const struct sctp_chunk *chunk,
1176         size_t size)
1177 {
1178         struct sctp_chunk *retval;
1179 
1180         retval = sctp_make_chunk(asoc, SCTP_CID_ERROR, 0,
1181                                  sizeof(sctp_errhdr_t) + size);
1182         if (!retval)
1183                 goto nodata;
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          */
1193         if (chunk)
1194                 retval->transport = chunk->transport;
1195 
1196 nodata:
1197         return retval;
1198 }
1199 
1200 /* Create an Operation Error chunk of a fixed size,
1201  * specifically, max(asoc->pathmtu, SCTP_DEFAULT_MAXSEGMENT)
1202  * This is a helper function to allocate an error chunk for
1203  * for those invalid parameter codes in which we may not want
1204  * to report all the errors, if the incoming chunk is large
1205  */
1206 static inline struct sctp_chunk *sctp_make_op_error_fixed(
1207         const struct sctp_association *asoc,
1208         const struct sctp_chunk *chunk)
1209 {
1210         size_t size = asoc ? asoc->pathmtu : 0;
1211 
1212         if (!size)
1213                 size = SCTP_DEFAULT_MAXSEGMENT;
1214 
1215         return sctp_make_op_error_space(asoc, chunk, size);
1216 }
1217 
1218 /* Create an Operation Error chunk.  */
1219 struct sctp_chunk *sctp_make_op_error(const struct sctp_association *asoc,
1220                                  const struct sctp_chunk *chunk,
1221                                  __be16 cause_code, const void *payload,
1222                                  size_t paylen, size_t reserve_tail)
1223 {
1224         struct sctp_chunk *retval;
1225 
1226         retval = sctp_make_op_error_space(asoc, chunk, paylen + reserve_tail);
1227         if (!retval)
1228                 goto nodata;
1229 
1230         sctp_init_cause(retval, cause_code, paylen + reserve_tail);
1231         sctp_addto_chunk(retval, paylen, payload);
1232         if (reserve_tail)
1233                 sctp_addto_param(retval, reserve_tail, NULL);
1234 
1235 nodata:
1236         return retval;
1237 }
1238 
1239 struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc)
1240 {
1241         struct sctp_chunk *retval;
1242         struct sctp_hmac *hmac_desc;
1243         struct sctp_authhdr auth_hdr;
1244         __u8 *hmac;
1245 
1246         /* Get the first hmac that the peer told us to use */
1247         hmac_desc = sctp_auth_asoc_get_hmac(asoc);
1248         if (unlikely(!hmac_desc))
1249                 return NULL;
1250 
1251         retval = sctp_make_chunk(asoc, SCTP_CID_AUTH, 0,
1252                         hmac_desc->hmac_len + sizeof(sctp_authhdr_t));
1253         if (!retval)
1254                 return NULL;
1255 
1256         auth_hdr.hmac_id = htons(hmac_desc->hmac_id);
1257         auth_hdr.shkey_id = htons(asoc->active_key_id);
1258 
1259         retval->subh.auth_hdr = sctp_addto_chunk(retval, sizeof(sctp_authhdr_t),
1260                                                 &auth_hdr);
1261 
1262         hmac = skb_put(retval->skb, hmac_desc->hmac_len);
1263         memset(hmac, 0, hmac_desc->hmac_len);
1264 
1265         /* Adjust the chunk header to include the empty MAC */
1266         retval->chunk_hdr->length =
1267                 htons(ntohs(retval->chunk_hdr->length) + hmac_desc->hmac_len);
1268         retval->chunk_end = skb_tail_pointer(retval->skb);
1269 
1270         return retval;
1271 }
1272 
1273 
1274 /********************************************************************
1275  * 2nd Level Abstractions
1276  ********************************************************************/
1277 
1278 /* Turn an skb into a chunk.
1279  * FIXME: Eventually move the structure directly inside the skb->cb[].
1280  */
1281 struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
1282                             const struct sctp_association *asoc,
1283                             struct sock *sk)
1284 {
1285         struct sctp_chunk *retval;
1286 
1287         retval = kmem_cache_zalloc(sctp_chunk_cachep, GFP_ATOMIC);
1288 
1289         if (!retval)
1290                 goto nodata;
1291         if (!sk)
1292                 pr_debug("%s: chunkifying skb:%p w/o an sk\n", __func__, skb);
1293 
1294         INIT_LIST_HEAD(&retval->list);
1295         retval->skb             = skb;
1296         retval->asoc            = (struct sctp_association *)asoc;
1297         retval->has_tsn         = 0;
1298         retval->has_ssn         = 0;
1299         retval->rtt_in_progress = 0;
1300         retval->sent_at         = 0;
1301         retval->singleton       = 1;
1302         retval->end_of_packet   = 0;
1303         retval->ecn_ce_done     = 0;
1304         retval->pdiscard        = 0;
1305 
1306         /* sctpimpguide-05.txt Section 2.8.2
1307          * M1) Each time a new DATA chunk is transmitted
1308          * set the 'TSN.Missing.Report' count for that TSN to 0. The
1309          * 'TSN.Missing.Report' count will be used to determine missing chunks
1310          * and when to fast retransmit.
1311          */
1312         retval->tsn_missing_report = 0;
1313         retval->tsn_gap_acked = 0;
1314         retval->fast_retransmit = SCTP_CAN_FRTX;
1315 
1316         /* If this is a fragmented message, track all fragments
1317          * of the message (for SEND_FAILED).
1318          */
1319         retval->msg = NULL;
1320 
1321         /* Polish the bead hole.  */
1322         INIT_LIST_HEAD(&retval->transmitted_list);
1323         INIT_LIST_HEAD(&retval->frag_list);
1324         SCTP_DBG_OBJCNT_INC(chunk);
1325         atomic_set(&retval->refcnt, 1);
1326 
1327 nodata:
1328         return retval;
1329 }
1330 
1331 /* Set chunk->source and dest based on the IP header in chunk->skb.  */
1332 void sctp_init_addrs(struct sctp_chunk *chunk, union sctp_addr *src,
1333                      union sctp_addr *dest)
1334 {
1335         memcpy(&chunk->source, src, sizeof(union sctp_addr));
1336         memcpy(&chunk->dest, dest, sizeof(union sctp_addr));
1337 }
1338 
1339 /* Extract the source address from a chunk.  */
1340 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk)
1341 {
1342         /* If we have a known transport, use that.  */
1343         if (chunk->transport) {
1344                 return &chunk->transport->ipaddr;
1345         } else {
1346                 /* Otherwise, extract it from the IP header.  */
1347                 return &chunk->source;
1348         }
1349 }
1350 
1351 /* Create a new chunk, setting the type and flags headers from the
1352  * arguments, reserving enough space for a 'paylen' byte payload.
1353  */
1354 static struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc,
1355                                           __u8 type, __u8 flags, int paylen)
1356 {
1357         struct sctp_chunk *retval;
1358         sctp_chunkhdr_t *chunk_hdr;
1359         struct sk_buff *skb;
1360         struct sock *sk;
1361 
1362         /* No need to allocate LL here, as this is only a chunk. */
1363         skb = alloc_skb(WORD_ROUND(sizeof(sctp_chunkhdr_t) + paylen),
1364                         GFP_ATOMIC);
1365         if (!skb)
1366                 goto nodata;
1367 
1368         /* Make room for the chunk header.  */
1369         chunk_hdr = (sctp_chunkhdr_t *)skb_put(skb, sizeof(sctp_chunkhdr_t));
1370         chunk_hdr->type   = type;
1371         chunk_hdr->flags  = flags;
1372         chunk_hdr->length = htons(sizeof(sctp_chunkhdr_t));
1373 
1374         sk = asoc ? asoc->base.sk : NULL;
1375         retval = sctp_chunkify(skb, asoc, sk);
1376         if (!retval) {
1377                 kfree_skb(skb);
1378                 goto nodata;
1379         }
1380 
1381         retval->chunk_hdr = chunk_hdr;
1382         retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(struct sctp_chunkhdr);
1383 
1384         /* Determine if the chunk needs to be authenticated */
1385         if (sctp_auth_send_cid(type, asoc))
1386                 retval->auth = 1;
1387 
1388         /* Set the skb to the belonging sock for accounting.  */
1389         skb->sk = sk;
1390 
1391         return retval;
1392 nodata:
1393         return NULL;
1394 }
1395 
1396 
1397 /* Release the memory occupied by a chunk.  */
1398 static void sctp_chunk_destroy(struct sctp_chunk *chunk)
1399 {
1400         BUG_ON(!list_empty(&chunk->list));
1401         list_del_init(&chunk->transmitted_list);
1402 
1403         /* Free the chunk skb data and the SCTP_chunk stub itself. */
1404         dev_kfree_skb(chunk->skb);
1405 
1406         SCTP_DBG_OBJCNT_DEC(chunk);
1407         kmem_cache_free(sctp_chunk_cachep, chunk);
1408 }
1409 
1410 /* Possibly, free the chunk.  */
1411 void sctp_chunk_free(struct sctp_chunk *chunk)
1412 {
1413         /* Release our reference on the message tracker. */
1414         if (chunk->msg)
1415                 sctp_datamsg_put(chunk->msg);
1416 
1417         sctp_chunk_put(chunk);
1418 }
1419 
1420 /* Grab a reference to the chunk. */
1421 void sctp_chunk_hold(struct sctp_chunk *ch)
1422 {
1423         atomic_inc(&ch->refcnt);
1424 }
1425 
1426 /* Release a reference to the chunk. */
1427 void sctp_chunk_put(struct sctp_chunk *ch)
1428 {
1429         if (atomic_dec_and_test(&ch->refcnt))
1430                 sctp_chunk_destroy(ch);
1431 }
1432 
1433 /* Append bytes to the end of a chunk.  Will panic if chunk is not big
1434  * enough.
1435  */
1436 void *sctp_addto_chunk(struct sctp_chunk *chunk, int len, const void *data)
1437 {
1438         void *target;
1439         void *padding;
1440         int chunklen = ntohs(chunk->chunk_hdr->length);
1441         int padlen = WORD_ROUND(chunklen) - chunklen;
1442 
1443         padding = skb_put(chunk->skb, padlen);
1444         target = skb_put(chunk->skb, len);
1445 
1446         memset(padding, 0, padlen);
1447         memcpy(target, data, len);
1448 
1449         /* Adjust the chunk length field.  */
1450         chunk->chunk_hdr->length = htons(chunklen + padlen + len);
1451         chunk->chunk_end = skb_tail_pointer(chunk->skb);
1452 
1453         return target;
1454 }
1455 
1456 /* Append bytes to the end of a chunk. Returns NULL if there isn't sufficient
1457  * space in the chunk
1458  */
1459 void *sctp_addto_chunk_fixed(struct sctp_chunk *chunk,
1460                              int len, const void *data)
1461 {
1462         if (skb_tailroom(chunk->skb) >= len)
1463                 return sctp_addto_chunk(chunk, len, data);
1464         else
1465                 return NULL;
1466 }
1467 
1468 /* Append bytes from user space to the end of a chunk.  Will panic if
1469  * chunk is not big enough.
1470  * Returns a kernel err value.
1471  */
1472 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int off, int len,
1473                           struct iovec *data)
1474 {
1475         __u8 *target;
1476         int err = 0;
1477 
1478         /* Make room in chunk for data.  */
1479         target = skb_put(chunk->skb, len);
1480 
1481         /* Copy data (whole iovec) into chunk */
1482         if ((err = memcpy_fromiovecend(target, data, off, len)))
1483                 goto out;
1484 
1485         /* Adjust the chunk length field.  */
1486         chunk->chunk_hdr->length =
1487                 htons(ntohs(chunk->chunk_hdr->length) + len);
1488         chunk->chunk_end = skb_tail_pointer(chunk->skb);
1489 
1490 out:
1491         return err;
1492 }
1493 
1494 /* Helper function to assign a TSN if needed.  This assumes that both
1495  * the data_hdr and association have already been assigned.
1496  */
1497 void sctp_chunk_assign_ssn(struct sctp_chunk *chunk)
1498 {
1499         struct sctp_datamsg *msg;
1500         struct sctp_chunk *lchunk;
1501         struct sctp_stream *stream;
1502         __u16 ssn;
1503         __u16 sid;
1504 
1505         if (chunk->has_ssn)
1506                 return;
1507 
1508         /* All fragments will be on the same stream */
1509         sid = ntohs(chunk->subh.data_hdr->stream);
1510         stream = &chunk->asoc->ssnmap->out;
1511 
1512         /* Now assign the sequence number to the entire message.
1513          * All fragments must have the same stream sequence number.
1514          */
1515         msg = chunk->msg;
1516         list_for_each_entry(lchunk, &msg->chunks, frag_list) {
1517                 if (lchunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
1518                         ssn = 0;
1519                 } else {
1520                         if (lchunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG)
1521                                 ssn = sctp_ssn_next(stream, sid);
1522                         else
1523                                 ssn = sctp_ssn_peek(stream, sid);
1524                 }
1525 
1526                 lchunk->subh.data_hdr->ssn = htons(ssn);
1527                 lchunk->has_ssn = 1;
1528         }
1529 }
1530 
1531 /* Helper function to assign a TSN if needed.  This assumes that both
1532  * the data_hdr and association have already been assigned.
1533  */
1534 void sctp_chunk_assign_tsn(struct sctp_chunk *chunk)
1535 {
1536         if (!chunk->has_tsn) {
1537                 /* This is the last possible instant to
1538                  * assign a TSN.
1539                  */
1540                 chunk->subh.data_hdr->tsn =
1541                         htonl(sctp_association_get_next_tsn(chunk->asoc));
1542                 chunk->has_tsn = 1;
1543         }
1544 }
1545 
1546 /* Create a CLOSED association to use with an incoming packet.  */
1547 struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *ep,
1548                                         struct sctp_chunk *chunk,
1549                                         gfp_t gfp)
1550 {
1551         struct sctp_association *asoc;
1552         struct sk_buff *skb;
1553         sctp_scope_t scope;
1554         struct sctp_af *af;
1555 
1556         /* Create the bare association.  */
1557         scope = sctp_scope(sctp_source(chunk));
1558         asoc = sctp_association_new(ep, ep->base.sk, scope, gfp);
1559         if (!asoc)
1560                 goto nodata;
1561         asoc->temp = 1;
1562         skb = chunk->skb;
1563         /* Create an entry for the source address of the packet.  */
1564         af = sctp_get_af_specific(ipver2af(ip_hdr(skb)->version));
1565         if (unlikely(!af))
1566                 goto fail;
1567         af->from_skb(&asoc->c.peer_addr, skb, 1);
1568 nodata:
1569         return asoc;
1570 
1571 fail:
1572         sctp_association_free(asoc);
1573         return NULL;
1574 }
1575 
1576 /* Build a cookie representing asoc.
1577  * This INCLUDES the param header needed to put the cookie in the INIT ACK.
1578  */
1579 static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
1580                                       const struct sctp_association *asoc,
1581                                       const struct sctp_chunk *init_chunk,
1582                                       int *cookie_len,
1583                                       const __u8 *raw_addrs, int addrs_len)
1584 {
1585         sctp_cookie_param_t *retval;
1586         struct sctp_signed_cookie *cookie;
1587         struct scatterlist sg;
1588         int headersize, bodysize;
1589 
1590         /* Header size is static data prior to the actual cookie, including
1591          * any padding.
1592          */
1593         headersize = sizeof(sctp_paramhdr_t) +
1594                      (sizeof(struct sctp_signed_cookie) -
1595                       sizeof(struct sctp_cookie));
1596         bodysize = sizeof(struct sctp_cookie)
1597                 + ntohs(init_chunk->chunk_hdr->length) + addrs_len;
1598 
1599         /* Pad out the cookie to a multiple to make the signature
1600          * functions simpler to write.
1601          */
1602         if (bodysize % SCTP_COOKIE_MULTIPLE)
1603                 bodysize += SCTP_COOKIE_MULTIPLE
1604                         - (bodysize % SCTP_COOKIE_MULTIPLE);
1605         *cookie_len = headersize + bodysize;
1606 
1607         /* Clear this memory since we are sending this data structure
1608          * out on the network.
1609          */
1610         retval = kzalloc(*cookie_len, GFP_ATOMIC);
1611         if (!retval)
1612                 goto nodata;
1613 
1614         cookie = (struct sctp_signed_cookie *) retval->body;
1615 
1616         /* Set up the parameter header.  */
1617         retval->p.type = SCTP_PARAM_STATE_COOKIE;
1618         retval->p.length = htons(*cookie_len);
1619 
1620         /* Copy the cookie part of the association itself.  */
1621         cookie->c = asoc->c;
1622         /* Save the raw address list length in the cookie. */
1623         cookie->c.raw_addr_list_len = addrs_len;
1624 
1625         /* Remember PR-SCTP capability. */
1626         cookie->c.prsctp_capable = asoc->peer.prsctp_capable;
1627 
1628         /* Save adaptation indication in the cookie. */
1629         cookie->c.adaptation_ind = asoc->peer.adaptation_ind;
1630 
1631         /* Set an expiration time for the cookie.  */
1632         cookie->c.expiration = ktime_add(asoc->cookie_life,
1633                                          ktime_get());
1634 
1635         /* Copy the peer's init packet.  */
1636         memcpy(&cookie->c.peer_init[0], init_chunk->chunk_hdr,
1637                ntohs(init_chunk->chunk_hdr->length));
1638 
1639         /* Copy the raw local address list of the association. */
1640         memcpy((__u8 *)&cookie->c.peer_init[0] +
1641                ntohs(init_chunk->chunk_hdr->length), raw_addrs, addrs_len);
1642 
1643         if (sctp_sk(ep->base.sk)->hmac) {
1644                 struct hash_desc desc;
1645 
1646                 /* Sign the message.  */
1647                 sg_init_one(&sg, &cookie->c, bodysize);
1648                 desc.tfm = sctp_sk(ep->base.sk)->hmac;
1649                 desc.flags = 0;
1650 
1651                 if (crypto_hash_setkey(desc.tfm, ep->secret_key,
1652                                        sizeof(ep->secret_key)) ||
1653                     crypto_hash_digest(&desc, &sg, bodysize, cookie->signature))
1654                         goto free_cookie;
1655         }
1656 
1657         return retval;
1658 
1659 free_cookie:
1660         kfree(retval);
1661 nodata:
1662         *cookie_len = 0;
1663         return NULL;
1664 }
1665 
1666 /* Unpack the cookie from COOKIE ECHO chunk, recreating the association.  */
1667 struct sctp_association *sctp_unpack_cookie(
1668         const struct sctp_endpoint *ep,
1669         const struct sctp_association *asoc,
1670         struct sctp_chunk *chunk, gfp_t gfp,
1671         int *error, struct sctp_chunk **errp)
1672 {
1673         struct sctp_association *retval = NULL;
1674         struct sctp_signed_cookie *cookie;
1675         struct sctp_cookie *bear_cookie;
1676         int headersize, bodysize, fixed_size;
1677         __u8 *digest = ep->digest;
1678         struct scatterlist sg;
1679         unsigned int len;
1680         sctp_scope_t scope;
1681         struct sk_buff *skb = chunk->skb;
1682         ktime_t kt;
1683         struct hash_desc desc;
1684 
1685         /* Header size is static data prior to the actual cookie, including
1686          * any padding.
1687          */
1688         headersize = sizeof(sctp_chunkhdr_t) +
1689                      (sizeof(struct sctp_signed_cookie) -
1690                       sizeof(struct sctp_cookie));
1691         bodysize = ntohs(chunk->chunk_hdr->length) - headersize;
1692         fixed_size = headersize + sizeof(struct sctp_cookie);
1693 
1694         /* Verify that the chunk looks like it even has a cookie.
1695          * There must be enough room for our cookie and our peer's
1696          * INIT chunk.
1697          */
1698         len = ntohs(chunk->chunk_hdr->length);
1699         if (len < fixed_size + sizeof(struct sctp_chunkhdr))
1700                 goto malformed;
1701 
1702         /* Verify that the cookie has been padded out. */
1703         if (bodysize % SCTP_COOKIE_MULTIPLE)
1704                 goto malformed;
1705 
1706         /* Process the cookie.  */
1707         cookie = chunk->subh.cookie_hdr;
1708         bear_cookie = &cookie->c;
1709 
1710         if (!sctp_sk(ep->base.sk)->hmac)
1711                 goto no_hmac;
1712 
1713         /* Check the signature.  */
1714         sg_init_one(&sg, bear_cookie, bodysize);
1715         desc.tfm = sctp_sk(ep->base.sk)->hmac;
1716         desc.flags = 0;
1717 
1718         memset(digest, 0x00, SCTP_SIGNATURE_SIZE);
1719         if (crypto_hash_setkey(desc.tfm, ep->secret_key,
1720                                sizeof(ep->secret_key)) ||
1721             crypto_hash_digest(&desc, &sg, bodysize, digest)) {
1722                 *error = -SCTP_IERROR_NOMEM;
1723                 goto fail;
1724         }
1725 
1726         if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
1727                 *error = -SCTP_IERROR_BAD_SIG;
1728                 goto fail;
1729         }
1730 
1731 no_hmac:
1732         /* IG Section 2.35.2:
1733          *  3) Compare the port numbers and the verification tag contained
1734          *     within the COOKIE ECHO chunk to the actual port numbers and the
1735          *     verification tag within the SCTP common header of the received
1736          *     packet. If these values do not match the packet MUST be silently
1737          *     discarded,
1738          */
1739         if (ntohl(chunk->sctp_hdr->vtag) != bear_cookie->my_vtag) {
1740                 *error = -SCTP_IERROR_BAD_TAG;
1741                 goto fail;
1742         }
1743 
1744         if (chunk->sctp_hdr->source != bear_cookie->peer_addr.v4.sin_port ||
1745             ntohs(chunk->sctp_hdr->dest) != bear_cookie->my_port) {
1746                 *error = -SCTP_IERROR_BAD_PORTS;
1747                 goto fail;
1748         }
1749 
1750         /* Check to see if the cookie is stale.  If there is already
1751          * an association, there is no need to check cookie's expiration
1752          * for init collision case of lost COOKIE ACK.
1753          * If skb has been timestamped, then use the stamp, otherwise
1754          * use current time.  This introduces a small possibility that
1755          * that a cookie may be considered expired, but his would only slow
1756          * down the new association establishment instead of every packet.
1757          */
1758         if (sock_flag(ep->base.sk, SOCK_TIMESTAMP))
1759                 kt = skb_get_ktime(skb);
1760         else
1761                 kt = ktime_get();
1762 
1763         if (!asoc && ktime_compare(bear_cookie->expiration, kt) < 0) {
1764                 /*
1765                  * Section 3.3.10.3 Stale Cookie Error (3)
1766                  *
1767                  * Cause of error
1768                  * ---------------
1769                  * Stale Cookie Error:  Indicates the receipt of a valid State
1770                  * Cookie that has expired.
1771                  */
1772                 len = ntohs(chunk->chunk_hdr->length);
1773                 *errp = sctp_make_op_error_space(asoc, chunk, len);
1774                 if (*errp) {
1775                         suseconds_t usecs = ktime_to_us(ktime_sub(kt, bear_cookie->expiration));
1776                         __be32 n = htonl(usecs);
1777 
1778                         sctp_init_cause(*errp, SCTP_ERROR_STALE_COOKIE,
1779                                         sizeof(n));
1780                         sctp_addto_chunk(*errp, sizeof(n), &n);
1781                         *error = -SCTP_IERROR_STALE_COOKIE;
1782                 } else
1783                         *error = -SCTP_IERROR_NOMEM;
1784 
1785                 goto fail;
1786         }
1787 
1788         /* Make a new base association.  */
1789         scope = sctp_scope(sctp_source(chunk));
1790         retval = sctp_association_new(ep, ep->base.sk, scope, gfp);
1791         if (!retval) {
1792                 *error = -SCTP_IERROR_NOMEM;
1793                 goto fail;
1794         }
1795 
1796         /* Set up our peer's port number.  */
1797         retval->peer.port = ntohs(chunk->sctp_hdr->source);
1798 
1799         /* Populate the association from the cookie.  */
1800         memcpy(&retval->c, bear_cookie, sizeof(*bear_cookie));
1801 
1802         if (sctp_assoc_set_bind_addr_from_cookie(retval, bear_cookie,
1803                                                  GFP_ATOMIC) < 0) {
1804                 *error = -SCTP_IERROR_NOMEM;
1805                 goto fail;
1806         }
1807 
1808         /* Also, add the destination address. */
1809         if (list_empty(&retval->base.bind_addr.address_list)) {
1810                 sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest,
1811                                 SCTP_ADDR_SRC, GFP_ATOMIC);
1812         }
1813 
1814         retval->next_tsn = retval->c.initial_tsn;
1815         retval->ctsn_ack_point = retval->next_tsn - 1;
1816         retval->addip_serial = retval->c.initial_tsn;
1817         retval->adv_peer_ack_point = retval->ctsn_ack_point;
1818         retval->peer.prsctp_capable = retval->c.prsctp_capable;
1819         retval->peer.adaptation_ind = retval->c.adaptation_ind;
1820 
1821         /* The INIT stuff will be done by the side effects.  */
1822         return retval;
1823 
1824 fail:
1825         if (retval)
1826                 sctp_association_free(retval);
1827 
1828         return NULL;
1829 
1830 malformed:
1831         /* Yikes!  The packet is either corrupt or deliberately
1832          * malformed.
1833          */
1834         *error = -SCTP_IERROR_MALFORMED;
1835         goto fail;
1836 }
1837 
1838 /********************************************************************
1839  * 3rd Level Abstractions
1840  ********************************************************************/
1841 
1842 struct __sctp_missing {
1843         __be32 num_missing;
1844         __be16 type;
1845 }  __packed;
1846 
1847 /*
1848  * Report a missing mandatory parameter.
1849  */
1850 static int sctp_process_missing_param(const struct sctp_association *asoc,
1851                                       sctp_param_t paramtype,
1852                                       struct sctp_chunk *chunk,
1853                                       struct sctp_chunk **errp)
1854 {
1855         struct __sctp_missing report;
1856         __u16 len;
1857 
1858         len = WORD_ROUND(sizeof(report));
1859 
1860         /* Make an ERROR chunk, preparing enough room for
1861          * returning multiple unknown parameters.
1862          */
1863         if (!*errp)
1864                 *errp = sctp_make_op_error_space(asoc, chunk, len);
1865 
1866         if (*errp) {
1867                 report.num_missing = htonl(1);
1868                 report.type = paramtype;
1869                 sctp_init_cause(*errp, SCTP_ERROR_MISS_PARAM,
1870                                 sizeof(report));
1871                 sctp_addto_chunk(*errp, sizeof(report), &report);
1872         }
1873 
1874         /* Stop processing this chunk. */
1875         return 0;
1876 }
1877 
1878 /* Report an Invalid Mandatory Parameter.  */
1879 static int sctp_process_inv_mandatory(const struct sctp_association *asoc,
1880                                       struct sctp_chunk *chunk,
1881                                       struct sctp_chunk **errp)
1882 {
1883         /* Invalid Mandatory Parameter Error has no payload. */
1884 
1885         if (!*errp)
1886                 *errp = sctp_make_op_error_space(asoc, chunk, 0);
1887 
1888         if (*errp)
1889                 sctp_init_cause(*errp, SCTP_ERROR_INV_PARAM, 0);
1890 
1891         /* Stop processing this chunk. */
1892         return 0;
1893 }
1894 
1895 static int sctp_process_inv_paramlength(const struct sctp_association *asoc,
1896                                         struct sctp_paramhdr *param,
1897                                         const struct sctp_chunk *chunk,
1898                                         struct sctp_chunk **errp)
1899 {
1900         /* This is a fatal error.  Any accumulated non-fatal errors are
1901          * not reported.
1902          */
1903         if (*errp)
1904                 sctp_chunk_free(*errp);
1905 
1906         /* Create an error chunk and fill it in with our payload. */
1907         *errp = sctp_make_violation_paramlen(asoc, chunk, param);
1908 
1909         return 0;
1910 }
1911 
1912 
1913 /* Do not attempt to handle the HOST_NAME parm.  However, do
1914  * send back an indicator to the peer.
1915  */
1916 static int sctp_process_hn_param(const struct sctp_association *asoc,
1917                                  union sctp_params param,
1918                                  struct sctp_chunk *chunk,
1919                                  struct sctp_chunk **errp)
1920 {
1921         __u16 len = ntohs(param.p->length);
1922 
1923         /* Processing of the HOST_NAME parameter will generate an
1924          * ABORT.  If we've accumulated any non-fatal errors, they
1925          * would be unrecognized parameters and we should not include
1926          * them in the ABORT.
1927          */
1928         if (*errp)
1929                 sctp_chunk_free(*errp);
1930 
1931         *errp = sctp_make_op_error_space(asoc, chunk, len);
1932 
1933         if (*errp) {
1934                 sctp_init_cause(*errp, SCTP_ERROR_DNS_FAILED, len);
1935                 sctp_addto_chunk(*errp, len, param.v);
1936         }
1937 
1938         /* Stop processing this chunk. */
1939         return 0;
1940 }
1941 
1942 static int sctp_verify_ext_param(struct net *net, union sctp_params param)
1943 {
1944         __u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
1945         int have_auth = 0;
1946         int have_asconf = 0;
1947         int i;
1948 
1949         for (i = 0; i < num_ext; i++) {
1950                 switch (param.ext->chunks[i]) {
1951                     case SCTP_CID_AUTH:
1952                             have_auth = 1;
1953                             break;
1954                     case SCTP_CID_ASCONF:
1955                     case SCTP_CID_ASCONF_ACK:
1956                             have_asconf = 1;
1957                             break;
1958                 }
1959         }
1960 
1961         /* ADD-IP Security: The draft requires us to ABORT or ignore the
1962          * INIT/INIT-ACK if ADD-IP is listed, but AUTH is not.  Do this
1963          * only if ADD-IP is turned on and we are not backward-compatible
1964          * mode.
1965          */
1966         if (net->sctp.addip_noauth)
1967                 return 1;
1968 
1969         if (net->sctp.addip_enable && !have_auth && have_asconf)
1970                 return 0;
1971 
1972         return 1;
1973 }
1974 
1975 static void sctp_process_ext_param(struct sctp_association *asoc,
1976                                     union sctp_params param)
1977 {
1978         struct net *net = sock_net(asoc->base.sk);
1979         __u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
1980         int i;
1981 
1982         for (i = 0; i < num_ext; i++) {
1983                 switch (param.ext->chunks[i]) {
1984                     case SCTP_CID_FWD_TSN:
1985                             if (net->sctp.prsctp_enable &&
1986                                 !asoc->peer.prsctp_capable)
1987                                     asoc->peer.prsctp_capable = 1;
1988                             break;
1989                     case SCTP_CID_AUTH:
1990                             /* if the peer reports AUTH, assume that he
1991                              * supports AUTH.
1992                              */
1993                             if (net->sctp.auth_enable)
1994                                     asoc->peer.auth_capable = 1;
1995                             break;
1996                     case SCTP_CID_ASCONF:
1997                     case SCTP_CID_ASCONF_ACK:
1998                             if (net->sctp.addip_enable)
1999                                     asoc->peer.asconf_capable = 1;
2000                             break;
2001                     default:
2002                             break;
2003                 }
2004         }
2005 }
2006 
2007 /* RFC 3.2.1 & the Implementers Guide 2.2.
2008  *
2009  * The Parameter Types are encoded such that the
2010  * highest-order two bits specify the action that must be
2011  * taken if the processing endpoint does not recognize the
2012  * Parameter Type.
2013  *
2014  * 00 - Stop processing this parameter; do not process any further
2015  *      parameters within this chunk
2016  *
2017  * 01 - Stop processing this parameter, do not process any further
2018  *      parameters within this chunk, and report the unrecognized
2019  *      parameter in an 'Unrecognized Parameter' ERROR chunk.
2020  *
2021  * 10 - Skip this parameter and continue processing.
2022  *
2023  * 11 - Skip this parameter and continue processing but
2024  *      report the unrecognized parameter in an
2025  *      'Unrecognized Parameter' ERROR chunk.
2026  *
2027  * Return value:
2028  *      SCTP_IERROR_NO_ERROR - continue with the chunk
2029  *      SCTP_IERROR_ERROR    - stop and report an error.
2030  *      SCTP_IERROR_NOMEME   - out of memory.
2031  */
2032 static sctp_ierror_t sctp_process_unk_param(const struct sctp_association *asoc,
2033                                             union sctp_params param,
2034                                             struct sctp_chunk *chunk,
2035                                             struct sctp_chunk **errp)
2036 {
2037         int retval = SCTP_IERROR_NO_ERROR;
2038 
2039         switch (param.p->type & SCTP_PARAM_ACTION_MASK) {
2040         case SCTP_PARAM_ACTION_DISCARD:
2041                 retval =  SCTP_IERROR_ERROR;
2042                 break;
2043         case SCTP_PARAM_ACTION_SKIP:
2044                 break;
2045         case SCTP_PARAM_ACTION_DISCARD_ERR:
2046                 retval =  SCTP_IERROR_ERROR;
2047                 /* Fall through */
2048         case SCTP_PARAM_ACTION_SKIP_ERR:
2049                 /* Make an ERROR chunk, preparing enough room for
2050                  * returning multiple unknown parameters.
2051                  */
2052                 if (NULL == *errp)
2053                         *errp = sctp_make_op_error_fixed(asoc, chunk);
2054 
2055                 if (*errp) {
2056                         if (!sctp_init_cause_fixed(*errp, SCTP_ERROR_UNKNOWN_PARAM,
2057                                         WORD_ROUND(ntohs(param.p->length))))
2058                                 sctp_addto_chunk_fixed(*errp,
2059                                                 WORD_ROUND(ntohs(param.p->length)),
2060                                                 param.v);
2061                 } else {
2062                         /* If there is no memory for generating the ERROR
2063                          * report as specified, an ABORT will be triggered
2064                          * to the peer and the association won't be
2065                          * established.
2066                          */
2067                         retval = SCTP_IERROR_NOMEM;
2068                 }
2069                 break;
2070         default:
2071                 break;
2072         }
2073 
2074         return retval;
2075 }
2076 
2077 /* Verify variable length parameters
2078  * Return values:
2079  *      SCTP_IERROR_ABORT - trigger an ABORT
2080  *      SCTP_IERROR_NOMEM - out of memory (abort)
2081  *      SCTP_IERROR_ERROR - stop processing, trigger an ERROR
2082  *      SCTP_IERROR_NO_ERROR - continue with the chunk
2083  */
2084 static sctp_ierror_t sctp_verify_param(struct net *net,
2085                                         const struct sctp_association *asoc,
2086                                         union sctp_params param,
2087                                         sctp_cid_t cid,
2088                                         struct sctp_chunk *chunk,
2089                                         struct sctp_chunk **err_chunk)
2090 {
2091         struct sctp_hmac_algo_param *hmacs;
2092         int retval = SCTP_IERROR_NO_ERROR;
2093         __u16 n_elt, id = 0;
2094         int i;
2095 
2096         /* FIXME - This routine is not looking at each parameter per the
2097          * chunk type, i.e., unrecognized parameters should be further
2098          * identified based on the chunk id.
2099          */
2100 
2101         switch (param.p->type) {
2102         case SCTP_PARAM_IPV4_ADDRESS:
2103         case SCTP_PARAM_IPV6_ADDRESS:
2104         case SCTP_PARAM_COOKIE_PRESERVATIVE:
2105         case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2106         case SCTP_PARAM_STATE_COOKIE:
2107         case SCTP_PARAM_HEARTBEAT_INFO:
2108         case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2109         case SCTP_PARAM_ECN_CAPABLE:
2110         case SCTP_PARAM_ADAPTATION_LAYER_IND:
2111                 break;
2112 
2113         case SCTP_PARAM_SUPPORTED_EXT:
2114                 if (!sctp_verify_ext_param(net, param))
2115                         return SCTP_IERROR_ABORT;
2116                 break;
2117 
2118         case SCTP_PARAM_SET_PRIMARY:
2119                 if (net->sctp.addip_enable)
2120                         break;
2121                 goto fallthrough;
2122 
2123         case SCTP_PARAM_HOST_NAME_ADDRESS:
2124                 /* Tell the peer, we won't support this param.  */
2125                 sctp_process_hn_param(asoc, param, chunk, err_chunk);
2126                 retval = SCTP_IERROR_ABORT;
2127                 break;
2128 
2129         case SCTP_PARAM_FWD_TSN_SUPPORT:
2130                 if (net->sctp.prsctp_enable)
2131                         break;
2132                 goto fallthrough;
2133 
2134         case SCTP_PARAM_RANDOM:
2135                 if (!net->sctp.auth_enable)
2136                         goto fallthrough;
2137 
2138                 /* SCTP-AUTH: Secion 6.1
2139                  * If the random number is not 32 byte long the association
2140                  * MUST be aborted.  The ABORT chunk SHOULD contain the error
2141                  * cause 'Protocol Violation'.
2142                  */
2143                 if (SCTP_AUTH_RANDOM_LENGTH !=
2144                         ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) {
2145                         sctp_process_inv_paramlength(asoc, param.p,
2146                                                         chunk, err_chunk);
2147                         retval = SCTP_IERROR_ABORT;
2148                 }
2149                 break;
2150 
2151         case SCTP_PARAM_CHUNKS:
2152                 if (!net->sctp.auth_enable)
2153                         goto fallthrough;
2154 
2155                 /* SCTP-AUTH: Section 3.2
2156                  * The CHUNKS parameter MUST be included once in the INIT or
2157                  *  INIT-ACK chunk if the sender wants to receive authenticated
2158                  *  chunks.  Its maximum length is 260 bytes.
2159                  */
2160                 if (260 < ntohs(param.p->length)) {
2161                         sctp_process_inv_paramlength(asoc, param.p,
2162                                                      chunk, err_chunk);
2163                         retval = SCTP_IERROR_ABORT;
2164                 }
2165                 break;
2166 
2167         case SCTP_PARAM_HMAC_ALGO:
2168                 if (!net->sctp.auth_enable)
2169                         goto fallthrough;
2170 
2171                 hmacs = (struct sctp_hmac_algo_param *)param.p;
2172                 n_elt = (ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) >> 1;
2173 
2174                 /* SCTP-AUTH: Section 6.1
2175                  * The HMAC algorithm based on SHA-1 MUST be supported and
2176                  * included in the HMAC-ALGO parameter.
2177                  */
2178                 for (i = 0; i < n_elt; i++) {
2179                         id = ntohs(hmacs->hmac_ids[i]);
2180 
2181                         if (id == SCTP_AUTH_HMAC_ID_SHA1)
2182                                 break;
2183                 }
2184 
2185                 if (id != SCTP_AUTH_HMAC_ID_SHA1) {
2186                         sctp_process_inv_paramlength(asoc, param.p, chunk,
2187                                                      err_chunk);
2188                         retval = SCTP_IERROR_ABORT;
2189                 }
2190                 break;
2191 fallthrough:
2192         default:
2193                 pr_debug("%s: unrecognized param:%d for chunk:%d\n",
2194                          __func__, ntohs(param.p->type), cid);
2195 
2196                 retval = sctp_process_unk_param(asoc, param, chunk, err_chunk);
2197                 break;
2198         }
2199         return retval;
2200 }
2201 
2202 /* Verify the INIT packet before we process it.  */
2203 int sctp_verify_init(struct net *net, const struct sctp_association *asoc,
2204                      sctp_cid_t cid,
2205                      sctp_init_chunk_t *peer_init,
2206                      struct sctp_chunk *chunk,
2207                      struct sctp_chunk **errp)
2208 {
2209         union sctp_params param;
2210         int has_cookie = 0;
2211         int result;
2212 
2213         /* Verify stream values are non-zero. */
2214         if ((0 == peer_init->init_hdr.num_outbound_streams) ||
2215             (0 == peer_init->init_hdr.num_inbound_streams) ||
2216             (0 == peer_init->init_hdr.init_tag) ||
2217             (SCTP_DEFAULT_MINWINDOW > ntohl(peer_init->init_hdr.a_rwnd))) {
2218 
2219                 return sctp_process_inv_mandatory(asoc, chunk, errp);
2220         }
2221 
2222         /* Check for missing mandatory parameters.  */
2223         sctp_walk_params(param, peer_init, init_hdr.params) {
2224 
2225                 if (SCTP_PARAM_STATE_COOKIE == param.p->type)
2226                         has_cookie = 1;
2227 
2228         } /* for (loop through all parameters) */
2229 
2230         /* There is a possibility that a parameter length was bad and
2231          * in that case we would have stoped walking the parameters.
2232          * The current param.p would point at the bad one.
2233          * Current consensus on the mailing list is to generate a PROTOCOL
2234          * VIOLATION error.  We build the ERROR chunk here and let the normal
2235          * error handling code build and send the packet.
2236          */
2237         if (param.v != (void*)chunk->chunk_end)
2238                 return sctp_process_inv_paramlength(asoc, param.p, chunk, errp);
2239 
2240         /* The only missing mandatory param possible today is
2241          * the state cookie for an INIT-ACK chunk.
2242          */
2243         if ((SCTP_CID_INIT_ACK == cid) && !has_cookie)
2244                 return sctp_process_missing_param(asoc, SCTP_PARAM_STATE_COOKIE,
2245                                                   chunk, errp);
2246 
2247         /* Verify all the variable length parameters */
2248         sctp_walk_params(param, peer_init, init_hdr.params) {
2249 
2250                 result = sctp_verify_param(net, asoc, param, cid, chunk, errp);
2251                 switch (result) {
2252                     case SCTP_IERROR_ABORT:
2253                     case SCTP_IERROR_NOMEM:
2254                                 return 0;
2255                     case SCTP_IERROR_ERROR:
2256                                 return 1;
2257                     case SCTP_IERROR_NO_ERROR:
2258                     default:
2259                                 break;
2260                 }
2261 
2262         } /* for (loop through all parameters) */
2263 
2264         return 1;
2265 }
2266 
2267 /* Unpack the parameters in an INIT packet into an association.
2268  * Returns 0 on failure, else success.
2269  * FIXME:  This is an association method.
2270  */
2271 int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,
2272                       const union sctp_addr *peer_addr,
2273                       sctp_init_chunk_t *peer_init, gfp_t gfp)
2274 {
2275         struct net *net = sock_net(asoc->base.sk);
2276         union sctp_params param;
2277         struct sctp_transport *transport;
2278         struct list_head *pos, *temp;
2279         struct sctp_af *af;
2280         union sctp_addr addr;
2281         char *cookie;
2282         int src_match = 0;
2283 
2284         /* We must include the address that the INIT packet came from.
2285          * This is the only address that matters for an INIT packet.
2286          * When processing a COOKIE ECHO, we retrieve the from address
2287          * of the INIT from the cookie.
2288          */
2289 
2290         /* This implementation defaults to making the first transport
2291          * added as the primary transport.  The source address seems to
2292          * be a a better choice than any of the embedded addresses.
2293          */
2294         if(!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
2295                 goto nomem;
2296 
2297         if (sctp_cmp_addr_exact(sctp_source(chunk), peer_addr))
2298                 src_match = 1;
2299 
2300         /* Process the initialization parameters.  */
2301         sctp_walk_params(param, peer_init, init_hdr.params) {
2302                 if (!src_match && (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
2303                     param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
2304                         af = sctp_get_af_specific(param_type2af(param.p->type));
2305                         af->from_addr_param(&addr, param.addr,
2306                                             chunk->sctp_hdr->source, 0);
2307                         if (sctp_cmp_addr_exact(sctp_source(chunk), &addr))
2308                                 src_match = 1;
2309                 }
2310 
2311                 if (!sctp_process_param(asoc, param, peer_addr, gfp))
2312                         goto clean_up;
2313         }
2314 
2315         /* source address of chunk may not match any valid address */
2316         if (!src_match)
2317                 goto clean_up;
2318 
2319         /* AUTH: After processing the parameters, make sure that we
2320          * have all the required info to potentially do authentications.
2321          */
2322         if (asoc->peer.auth_capable && (!asoc->peer.peer_random ||
2323                                         !asoc->peer.peer_hmacs))
2324                 asoc->peer.auth_capable = 0;
2325 
2326         /* In a non-backward compatible mode, if the peer claims
2327          * support for ADD-IP but not AUTH,  the ADD-IP spec states
2328          * that we MUST ABORT the association. Section 6.  The section
2329          * also give us an option to silently ignore the packet, which
2330          * is what we'll do here.
2331          */
2332         if (!net->sctp.addip_noauth &&
2333              (asoc->peer.asconf_capable && !asoc->peer.auth_capable)) {
2334                 asoc->peer.addip_disabled_mask |= (SCTP_PARAM_ADD_IP |
2335                                                   SCTP_PARAM_DEL_IP |
2336                                                   SCTP_PARAM_SET_PRIMARY);
2337                 asoc->peer.asconf_capable = 0;
2338                 goto clean_up;
2339         }
2340 
2341         /* Walk list of transports, removing transports in the UNKNOWN state. */
2342         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2343                 transport = list_entry(pos, struct sctp_transport, transports);
2344                 if (transport->state == SCTP_UNKNOWN) {
2345                         sctp_assoc_rm_peer(asoc, transport);
2346                 }
2347         }
2348 
2349         /* The fixed INIT headers are always in network byte
2350          * order.
2351          */
2352         asoc->peer.i.init_tag =
2353                 ntohl(peer_init->init_hdr.init_tag);
2354         asoc->peer.i.a_rwnd =
2355                 ntohl(peer_init->init_hdr.a_rwnd);
2356         asoc->peer.i.num_outbound_streams =
2357                 ntohs(peer_init->init_hdr.num_outbound_streams);
2358         asoc->peer.i.num_inbound_streams =
2359                 ntohs(peer_init->init_hdr.num_inbound_streams);
2360         asoc->peer.i.initial_tsn =
2361                 ntohl(peer_init->init_hdr.initial_tsn);
2362 
2363         /* Apply the upper bounds for output streams based on peer's
2364          * number of inbound streams.
2365          */
2366         if (asoc->c.sinit_num_ostreams  >
2367             ntohs(peer_init->init_hdr.num_inbound_streams)) {
2368                 asoc->c.sinit_num_ostreams =
2369                         ntohs(peer_init->init_hdr.num_inbound_streams);
2370         }
2371 
2372         if (asoc->c.sinit_max_instreams >
2373             ntohs(peer_init->init_hdr.num_outbound_streams)) {
2374                 asoc->c.sinit_max_instreams =
2375                         ntohs(peer_init->init_hdr.num_outbound_streams);
2376         }
2377 
2378         /* Copy Initiation tag from INIT to VT_peer in cookie.   */
2379         asoc->c.peer_vtag = asoc->peer.i.init_tag;
2380 
2381         /* Peer Rwnd   : Current calculated value of the peer's rwnd.  */
2382         asoc->peer.rwnd = asoc->peer.i.a_rwnd;
2383 
2384         /* Copy cookie in case we need to resend COOKIE-ECHO. */
2385         cookie = asoc->peer.cookie;
2386         if (cookie) {
2387                 asoc->peer.cookie = kmemdup(cookie, asoc->peer.cookie_len, gfp);
2388                 if (!asoc->peer.cookie)
2389                         goto clean_up;
2390         }
2391 
2392         /* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily
2393          * high (for example, implementations MAY use the size of the receiver
2394          * advertised window).
2395          */
2396         list_for_each_entry(transport, &asoc->peer.transport_addr_list,
2397                         transports) {
2398                 transport->ssthresh = asoc->peer.i.a_rwnd;
2399         }
2400 
2401         /* Set up the TSN tracking pieces.  */
2402         if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
2403                                 asoc->peer.i.initial_tsn, gfp))
2404                 goto clean_up;
2405 
2406         /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
2407          *
2408          * The stream sequence number in all the streams shall start
2409          * from 0 when the association is established.  Also, when the
2410          * stream sequence number reaches the value 65535 the next
2411          * stream sequence number shall be set to 0.
2412          */
2413 
2414         /* Allocate storage for the negotiated streams if it is not a temporary
2415          * association.
2416          */
2417         if (!asoc->temp) {
2418                 int error;
2419 
2420                 asoc->ssnmap = sctp_ssnmap_new(asoc->c.sinit_max_instreams,
2421                                                asoc->c.sinit_num_ostreams, gfp);
2422                 if (!asoc->ssnmap)
2423                         goto clean_up;
2424 
2425                 error = sctp_assoc_set_id(asoc, gfp);
2426                 if (error)
2427                         goto clean_up;
2428         }
2429 
2430         /* ADDIP Section 4.1 ASCONF Chunk Procedures
2431          *
2432          * When an endpoint has an ASCONF signaled change to be sent to the
2433          * remote endpoint it should do the following:
2434          * ...
2435          * A2) A serial number should be assigned to the Chunk. The serial
2436          * number should be a monotonically increasing number. All serial
2437          * numbers are defined to be initialized at the start of the
2438          * association to the same value as the Initial TSN.
2439          */
2440         asoc->peer.addip_serial = asoc->peer.i.initial_tsn - 1;
2441         return 1;
2442 
2443 clean_up:
2444         /* Release the transport structures. */
2445         list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2446                 transport = list_entry(pos, struct sctp_transport, transports);
2447                 if (transport->state != SCTP_ACTIVE)
2448                         sctp_assoc_rm_peer(asoc, transport);
2449         }
2450 
2451 nomem:
2452         return 0;
2453 }
2454 
2455 
2456 /* Update asoc with the option described in param.
2457  *
2458  * RFC2960 3.3.2.1 Optional/Variable Length Parameters in INIT
2459  *
2460  * asoc is the association to update.
2461  * param is the variable length parameter to use for update.
2462  * cid tells us if this is an INIT, INIT ACK or COOKIE ECHO.
2463  * If the current packet is an INIT we want to minimize the amount of
2464  * work we do.  In particular, we should not build transport
2465  * structures for the addresses.
2466  */
2467 static int sctp_process_param(struct sctp_association *asoc,
2468                               union sctp_params param,
2469                               const union sctp_addr *peer_addr,
2470                               gfp_t gfp)
2471 {
2472         struct net *net = sock_net(asoc->base.sk);
2473         union sctp_addr addr;
2474         int i;
2475         __u16 sat;
2476         int retval = 1;
2477         sctp_scope_t scope;
2478         time_t stale;
2479         struct sctp_af *af;
2480         union sctp_addr_param *addr_param;
2481         struct sctp_transport *t;
2482 
2483         /* We maintain all INIT parameters in network byte order all the
2484          * time.  This allows us to not worry about whether the parameters
2485          * came from a fresh INIT, and INIT ACK, or were stored in a cookie.
2486          */
2487         switch (param.p->type) {
2488         case SCTP_PARAM_IPV6_ADDRESS:
2489                 if (PF_INET6 != asoc->base.sk->sk_family)
2490                         break;
2491                 goto do_addr_param;
2492 
2493         case SCTP_PARAM_IPV4_ADDRESS:
2494                 /* v4 addresses are not allowed on v6-only socket */
2495                 if (ipv6_only_sock(asoc->base.sk))
2496                         break;
2497 do_addr_param:
2498                 af = sctp_get_af_specific(param_type2af(param.p->type));
2499                 af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
2500                 scope = sctp_scope(peer_addr);
2501                 if (sctp_in_scope(net, &addr, scope))
2502                         if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
2503                                 return 0;
2504                 break;
2505 
2506         case SCTP_PARAM_COOKIE_PRESERVATIVE:
2507                 if (!net->sctp.cookie_preserve_enable)
2508                         break;
2509 
2510                 stale = ntohl(param.life->lifespan_increment);
2511 
2512                 /* Suggested Cookie Life span increment's unit is msec,
2513                  * (1/1000sec).
2514                  */
2515                 asoc->cookie_life = ktime_add_ms(asoc->cookie_life, stale);
2516                 break;
2517 
2518         case SCTP_PARAM_HOST_NAME_ADDRESS:
2519                 pr_debug("%s: unimplemented SCTP_HOST_NAME_ADDRESS\n", __func__);
2520                 break;
2521 
2522         case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2523                 /* Turn off the default values first so we'll know which
2524                  * ones are really set by the peer.
2525                  */
2526                 asoc->peer.ipv4_address = 0;
2527                 asoc->peer.ipv6_address = 0;
2528 
2529                 /* Assume that peer supports the address family
2530                  * by which it sends a packet.
2531                  */
2532                 if (peer_addr->sa.sa_family == AF_INET6)
2533                         asoc->peer.ipv6_address = 1;
2534                 else if (peer_addr->sa.sa_family == AF_INET)
2535                         asoc->peer.ipv4_address = 1;
2536 
2537                 /* Cycle through address types; avoid divide by 0. */
2538                 sat = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2539                 if (sat)
2540                         sat /= sizeof(__u16);
2541 
2542                 for (i = 0; i < sat; ++i) {
2543                         switch (param.sat->types[i]) {
2544                         case SCTP_PARAM_IPV4_ADDRESS:
2545                                 asoc->peer.ipv4_address = 1;
2546                                 break;
2547 
2548                         case SCTP_PARAM_IPV6_ADDRESS:
2549                                 if (PF_INET6 == asoc->base.sk->sk_family)
2550                                         asoc->peer.ipv6_address = 1;
2551                                 break;
2552 
2553                         case SCTP_PARAM_HOST_NAME_ADDRESS:
2554                                 asoc->peer.hostname_address = 1;
2555                                 break;
2556 
2557                         default: /* Just ignore anything else.  */
2558                                 break;
2559                         }
2560                 }
2561                 break;
2562 
2563         case SCTP_PARAM_STATE_COOKIE:
2564                 asoc->peer.cookie_len =
2565                         ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2566                 asoc->peer.cookie = param.cookie->body;
2567                 break;
2568 
2569         case SCTP_PARAM_HEARTBEAT_INFO:
2570                 /* Would be odd to receive, but it causes no problems. */
2571                 break;
2572 
2573         case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2574                 /* Rejected during verify stage. */
2575                 break;
2576 
2577         case SCTP_PARAM_ECN_CAPABLE:
2578                 asoc->peer.ecn_capable = 1;
2579                 break;
2580 
2581         case SCTP_PARAM_ADAPTATION_LAYER_IND:
2582                 asoc->peer.adaptation_ind = ntohl(param.aind->adaptation_ind);
2583                 break;
2584 
2585         case SCTP_PARAM_SET_PRIMARY:
2586                 if (!net->sctp.addip_enable)
2587                         goto fall_through;
2588 
2589                 addr_param = param.v + sizeof(sctp_addip_param_t);
2590 
2591                 af = sctp_get_af_specific(param_type2af(param.p->type));
2592                 af->from_addr_param(&addr, addr_param,
2593                                     htons(asoc->peer.port), 0);
2594 
2595                 /* if the address is invalid, we can't process it.
2596                  * XXX: see spec for what to do.
2597                  */
2598                 if (!af->addr_valid(&addr, NULL, NULL))
2599                         break;
2600 
2601                 t = sctp_assoc_lookup_paddr(asoc, &addr);
2602                 if (!t)
2603                         break;
2604 
2605                 sctp_assoc_set_primary(asoc, t);
2606                 break;
2607 
2608         case SCTP_PARAM_SUPPORTED_EXT:
2609                 sctp_process_ext_param(asoc, param);
2610                 break;
2611 
2612         case SCTP_PARAM_FWD_TSN_SUPPORT:
2613                 if (net->sctp.prsctp_enable) {
2614                         asoc->peer.prsctp_capable = 1;
2615                         break;
2616                 }
2617                 /* Fall Through */
2618                 goto fall_through;
2619 
2620         case SCTP_PARAM_RANDOM:
2621                 if (!net->sctp.auth_enable)
2622                         goto fall_through;
2623 
2624                 /* Save peer's random parameter */
2625                 asoc->peer.peer_random = kmemdup(param.p,
2626                                             ntohs(param.p->length), gfp);
2627                 if (!asoc->peer.peer_random) {
2628                         retval = 0;
2629                         break;
2630                 }
2631                 break;
2632 
2633         case SCTP_PARAM_HMAC_ALGO:
2634                 if (!net->sctp.auth_enable)
2635                         goto fall_through;
2636 
2637                 /* Save peer's HMAC list */
2638                 asoc->peer.peer_hmacs = kmemdup(param.p,
2639                                             ntohs(param.p->length), gfp);
2640                 if (!asoc->peer.peer_hmacs) {
2641                         retval = 0;
2642                         break;
2643                 }
2644 
2645                 /* Set the default HMAC the peer requested*/
2646                 sctp_auth_asoc_set_default_hmac(asoc, param.hmac_algo);
2647                 break;
2648 
2649         case SCTP_PARAM_CHUNKS:
2650                 if (!net->sctp.auth_enable)
2651                         goto fall_through;
2652 
2653                 asoc->peer.peer_chunks = kmemdup(param.p,
2654                                             ntohs(param.p->length), gfp);
2655                 if (!asoc->peer.peer_chunks)
2656                         retval = 0;
2657                 break;
2658 fall_through:
2659         default:
2660                 /* Any unrecognized parameters should have been caught
2661                  * and handled by sctp_verify_param() which should be
2662                  * called prior to this routine.  Simply log the error
2663                  * here.
2664                  */
2665                 pr_debug("%s: ignoring param:%d for association:%p.\n",
2666                          __func__, ntohs(param.p->type), asoc);
2667                 break;
2668         }
2669 
2670         return retval;
2671 }
2672 
2673 /* Select a new verification tag.  */
2674 __u32 sctp_generate_tag(const struct sctp_endpoint *ep)
2675 {
2676         /* I believe that this random number generator complies with RFC1750.
2677          * A tag of 0 is reserved for special cases (e.g. INIT).
2678          */
2679         __u32 x;
2680 
2681         do {
2682                 get_random_bytes(&x, sizeof(__u32));
2683         } while (x == 0);
2684 
2685         return x;
2686 }
2687 
2688 /* Select an initial TSN to send during startup.  */
2689 __u32 sctp_generate_tsn(const struct sctp_endpoint *ep)
2690 {
2691         __u32 retval;
2692 
2693         get_random_bytes(&retval, sizeof(__u32));
2694         return retval;
2695 }
2696 
2697 /*
2698  * ADDIP 3.1.1 Address Configuration Change Chunk (ASCONF)
2699  *      0                   1                   2                   3
2700  *      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
2701  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2702  *     | Type = 0xC1   |  Chunk Flags  |      Chunk Length             |
2703  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2704  *     |                       Serial Number                           |
2705  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2706  *     |                    Address Parameter                          |
2707  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2708  *     |                     ASCONF Parameter #1                       |
2709  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2710  *     \                                                               \
2711  *     /                             ....                              /
2712  *     \                                                               \
2713  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2714  *     |                     ASCONF Parameter #N                       |
2715  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2716  *
2717  * Address Parameter and other parameter will not be wrapped in this function
2718  */
2719 static struct sctp_chunk *sctp_make_asconf(struct sctp_association *asoc,
2720                                            union sctp_addr *addr,
2721                                            int vparam_len)
2722 {
2723         sctp_addiphdr_t asconf;
2724         struct sctp_chunk *retval;
2725         int length = sizeof(asconf) + vparam_len;
2726         union sctp_addr_param addrparam;
2727         int addrlen;
2728         struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
2729 
2730         addrlen = af->to_addr_param(addr, &addrparam);
2731         if (!addrlen)
2732                 return NULL;
2733         length += addrlen;
2734 
2735         /* Create the chunk.  */
2736         retval = sctp_make_chunk(asoc, SCTP_CID_ASCONF, 0, length);
2737         if (!retval)
2738                 return NULL;
2739 
2740         asconf.serial = htonl(asoc->addip_serial++);
2741 
2742         retval->subh.addip_hdr =
2743                 sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2744         retval->param_hdr.v =
2745                 sctp_addto_chunk(retval, addrlen, &addrparam);
2746 
2747         return retval;
2748 }
2749 
2750 /* ADDIP
2751  * 3.2.1 Add IP Address
2752  *      0                   1                   2                   3
2753  *      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
2754  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2755  *     |        Type = 0xC001          |    Length = Variable          |
2756  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2757  *     |               ASCONF-Request Correlation ID                   |
2758  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2759  *     |                       Address Parameter                       |
2760  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2761  *
2762  * 3.2.2 Delete IP Address
2763  *      0                   1                   2                   3
2764  *      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
2765  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2766  *     |        Type = 0xC002          |    Length = Variable          |
2767  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2768  *     |               ASCONF-Request Correlation ID                   |
2769  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2770  *     |                       Address Parameter                       |
2771  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2772  *
2773  */
2774 struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *asoc,
2775                                               union sctp_addr         *laddr,
2776                                               struct sockaddr         *addrs,
2777                                               int                     addrcnt,
2778                                               __be16                  flags)
2779 {
2780         sctp_addip_param_t      param;
2781         struct sctp_chunk       *retval;
2782         union sctp_addr_param   addr_param;
2783         union sctp_addr         *addr;
2784         void                    *addr_buf;
2785         struct sctp_af          *af;
2786         int                     paramlen = sizeof(param);
2787         int                     addr_param_len = 0;
2788         int                     totallen = 0;
2789         int                     i;
2790         int                     del_pickup = 0;
2791 
2792         /* Get total length of all the address parameters. */
2793         addr_buf = addrs;
2794         for (i = 0; i < addrcnt; i++) {
2795                 addr = addr_buf;
2796                 af = sctp_get_af_specific(addr->v4.sin_family);
2797                 addr_param_len = af->to_addr_param(addr, &addr_param);
2798 
2799                 totallen += paramlen;
2800                 totallen += addr_param_len;
2801 
2802                 addr_buf += af->sockaddr_len;
2803                 if (asoc->asconf_addr_del_pending && !del_pickup) {
2804                         /* reuse the parameter length from the same scope one */
2805                         totallen += paramlen;
2806                         totallen += addr_param_len;
2807                         del_pickup = 1;
2808 
2809                         pr_debug("%s: picked same-scope del_pending addr, "
2810                                  "totallen for all addresses is %d\n",
2811                                  __func__, totallen);
2812                 }
2813         }
2814 
2815         /* Create an asconf chunk with the required length. */
2816         retval = sctp_make_asconf(asoc, laddr, totallen);
2817         if (!retval)
2818                 return NULL;
2819 
2820         /* Add the address parameters to the asconf chunk. */
2821         addr_buf = addrs;
2822         for (i = 0; i < addrcnt; i++) {
2823                 addr = addr_buf;
2824                 af = sctp_get_af_specific(addr->v4.sin_family);
2825                 addr_param_len = af->to_addr_param(addr, &addr_param);
2826                 param.param_hdr.type = flags;
2827                 param.param_hdr.length = htons(paramlen + addr_param_len);
2828                 param.crr_id = i;
2829 
2830                 sctp_addto_chunk(retval, paramlen, &param);
2831                 sctp_addto_chunk(retval, addr_param_len, &addr_param);
2832 
2833                 addr_buf += af->sockaddr_len;
2834         }
2835         if (flags == SCTP_PARAM_ADD_IP && del_pickup) {
2836                 addr = asoc->asconf_addr_del_pending;
2837                 af = sctp_get_af_specific(addr->v4.sin_family);
2838                 addr_param_len = af->to_addr_param(addr, &addr_param);
2839                 param.param_hdr.type = SCTP_PARAM_DEL_IP;
2840                 param.param_hdr.length = htons(paramlen + addr_param_len);
2841                 param.crr_id = i;
2842 
2843                 sctp_addto_chunk(retval, paramlen, &param);
2844                 sctp_addto_chunk(retval, addr_param_len, &addr_param);
2845         }
2846         return retval;
2847 }
2848 
2849 /* ADDIP
2850  * 3.2.4 Set Primary IP Address
2851  *      0                   1                   2                   3
2852  *      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
2853  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2854  *     |        Type =0xC004           |    Length = Variable          |
2855  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2856  *     |               ASCONF-Request Correlation ID                   |
2857  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2858  *     |                       Address Parameter                       |
2859  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2860  *
2861  * Create an ASCONF chunk with Set Primary IP address parameter.
2862  */
2863 struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
2864                                              union sctp_addr *addr)
2865 {
2866         sctp_addip_param_t      param;
2867         struct sctp_chunk       *retval;
2868         int                     len = sizeof(param);
2869         union sctp_addr_param   addrparam;
2870         int                     addrlen;
2871         struct sctp_af          *af = sctp_get_af_specific(addr->v4.sin_family);
2872 
2873         addrlen = af->to_addr_param(addr, &addrparam);
2874         if (!addrlen)
2875                 return NULL;
2876         len += addrlen;
2877 
2878         /* Create the chunk and make asconf header. */
2879         retval = sctp_make_asconf(asoc, addr, len);
2880         if (!retval)
2881                 return NULL;
2882 
2883         param.param_hdr.type = SCTP_PARAM_SET_PRIMARY;
2884         param.param_hdr.length = htons(len);
2885         param.crr_id = 0;
2886 
2887         sctp_addto_chunk(retval, sizeof(param), &param);
2888         sctp_addto_chunk(retval, addrlen, &addrparam);
2889 
2890         return retval;
2891 }
2892 
2893 /* ADDIP 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
2894  *      0                   1                   2                   3
2895  *      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
2896  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2897  *     | Type = 0x80   |  Chunk Flags  |      Chunk Length             |
2898  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2899  *     |                       Serial Number                           |
2900  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2901  *     |                 ASCONF Parameter Response#1                   |
2902  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2903  *     \                                                               \
2904  *     /                             ....                              /
2905  *     \                                                               \
2906  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2907  *     |                 ASCONF Parameter Response#N                   |
2908  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2909  *
2910  * Create an ASCONF_ACK chunk with enough space for the parameter responses.
2911  */
2912 static struct sctp_chunk *sctp_make_asconf_ack(const struct sctp_association *asoc,
2913                                                __u32 serial, int vparam_len)
2914 {
2915         sctp_addiphdr_t         asconf;
2916         struct sctp_chunk       *retval;
2917         int                     length = sizeof(asconf) + vparam_len;
2918 
2919         /* Create the chunk.  */
2920         retval = sctp_make_chunk(asoc, SCTP_CID_ASCONF_ACK, 0, length);
2921         if (!retval)
2922                 return NULL;
2923 
2924         asconf.serial = htonl(serial);
2925 
2926         retval->subh.addip_hdr =
2927                 sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2928 
2929         return retval;
2930 }
2931 
2932 /* Add response parameters to an ASCONF_ACK chunk. */
2933 static void sctp_add_asconf_response(struct sctp_chunk *chunk, __be32 crr_id,
2934                               __be16 err_code, sctp_addip_param_t *asconf_param)
2935 {
2936         sctp_addip_param_t      ack_param;
2937         sctp_errhdr_t           err_param;
2938         int                     asconf_param_len = 0;
2939         int                     err_param_len = 0;
2940         __be16                  response_type;
2941 
2942         if (SCTP_ERROR_NO_ERROR == err_code) {
2943                 response_type = SCTP_PARAM_SUCCESS_REPORT;
2944         } else {
2945                 response_type = SCTP_PARAM_ERR_CAUSE;
2946                 err_param_len = sizeof(err_param);
2947                 if (asconf_param)
2948                         asconf_param_len =
2949                                  ntohs(asconf_param->param_hdr.length);
2950         }
2951 
2952         /* Add Success Indication or Error Cause Indication parameter. */
2953         ack_param.param_hdr.type = response_type;
2954         ack_param.param_hdr.length = htons(sizeof(ack_param) +
2955                                            err_param_len +
2956                                            asconf_param_len);
2957         ack_param.crr_id = crr_id;
2958         sctp_addto_chunk(chunk, sizeof(ack_param), &ack_param);
2959 
2960         if (SCTP_ERROR_NO_ERROR == err_code)
2961                 return;
2962 
2963         /* Add Error Cause parameter. */
2964         err_param.cause = err_code;
2965         err_param.length = htons(err_param_len + asconf_param_len);
2966         sctp_addto_chunk(chunk, err_param_len, &err_param);
2967 
2968         /* Add the failed TLV copied from ASCONF chunk. */
2969         if (asconf_param)
2970                 sctp_addto_chunk(chunk, asconf_param_len, asconf_param);
2971 }
2972 
2973 /* Process a asconf parameter. */
2974 static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
2975                                        struct sctp_chunk *asconf,
2976                                        sctp_addip_param_t *asconf_param)
2977 {
2978         struct sctp_transport *peer;
2979         struct sctp_af *af;
2980         union sctp_addr addr;
2981         union sctp_addr_param *addr_param;
2982 
2983         addr_param = (void *)asconf_param + sizeof(sctp_addip_param_t);
2984 
2985         if (asconf_param->param_hdr.type != SCTP_PARAM_ADD_IP &&
2986             asconf_param->param_hdr.type != SCTP_PARAM_DEL_IP &&
2987             asconf_param->param_hdr.type != SCTP_PARAM_SET_PRIMARY)
2988                 return SCTP_ERROR_UNKNOWN_PARAM;
2989 
2990         switch (addr_param->p.type) {
2991         case SCTP_PARAM_IPV6_ADDRESS:
2992                 if (!asoc->peer.ipv6_address)
2993                         return SCTP_ERROR_DNS_FAILED;
2994                 break;
2995         case SCTP_PARAM_IPV4_ADDRESS:
2996                 if (!asoc->peer.ipv4_address)
2997                         return SCTP_ERROR_DNS_FAILED;
2998                 break;
2999         default:
3000                 return SCTP_ERROR_DNS_FAILED;
3001         }
3002 
3003         af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3004         if (unlikely(!af))
3005                 return SCTP_ERROR_DNS_FAILED;
3006 
3007         af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);
3008 
3009         /* ADDIP 4.2.1  This parameter MUST NOT contain a broadcast
3010          * or multicast address.
3011          * (note: wildcard is permitted and requires special handling so
3012          *  make sure we check for that)
3013          */
3014         if (!af->is_any(&addr) && !af->addr_valid(&addr, NULL, asconf->skb))
3015                 return SCTP_ERROR_DNS_FAILED;
3016 
3017         switch (asconf_param->param_hdr.type) {
3018         case SCTP_PARAM_ADD_IP:
3019                 /* Section 4.2.1:
3020                  * If the address 0.0.0.0 or ::0 is provided, the source
3021                  * address of the packet MUST be added.
3022                  */
3023                 if (af->is_any(&addr))
3024                         memcpy(&addr, &asconf->source, sizeof(addr));
3025 
3026                 /* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
3027                  * request and does not have the local resources to add this
3028                  * new address to the association, it MUST return an Error
3029                  * Cause TLV set to the new error code 'Operation Refused
3030                  * Due to Resource Shortage'.
3031                  */
3032 
3033                 peer = sctp_assoc_add_peer(asoc, &addr, GFP_ATOMIC, SCTP_UNCONFIRMED);
3034                 if (!peer)
3035                         return SCTP_ERROR_RSRC_LOW;
3036 
3037                 /* Start the heartbeat timer. */
3038                 if (!mod_timer(&peer->hb_timer, sctp_transport_timeout(peer)))
3039                         sctp_transport_hold(peer);
3040                 asoc->new_transport = peer;
3041                 break;
3042         case SCTP_PARAM_DEL_IP:
3043                 /* ADDIP 4.3 D7) If a request is received to delete the
3044                  * last remaining IP address of a peer endpoint, the receiver
3045                  * MUST send an Error Cause TLV with the error cause set to the
3046                  * new error code 'Request to Delete Last Remaining IP Address'.
3047                  */
3048                 if (asoc->peer.transport_count == 1)
3049                         return SCTP_ERROR_DEL_LAST_IP;
3050 
3051                 /* ADDIP 4.3 D8) If a request is received to delete an IP
3052                  * address which is also the source address of the IP packet
3053                  * which contained the ASCONF chunk, the receiver MUST reject
3054                  * this request. To reject the request the receiver MUST send
3055                  * an Error Cause TLV set to the new error code 'Request to
3056                  * Delete Source IP Address'
3057                  */
3058                 if (sctp_cmp_addr_exact(&asconf->source, &addr))
3059                         return SCTP_ERROR_DEL_SRC_IP;
3060 
3061                 /* Section 4.2.2
3062                  * If the address 0.0.0.0 or ::0 is provided, all
3063                  * addresses of the peer except the source address of the
3064                  * packet MUST be deleted.
3065                  */
3066                 if (af->is_any(&addr)) {
3067                         sctp_assoc_set_primary(asoc, asconf->transport);
3068                         sctp_assoc_del_nonprimary_peers(asoc,
3069                                                         asconf->transport);
3070                 } else
3071                         sctp_assoc_del_peer(asoc, &addr);
3072                 break;
3073         case SCTP_PARAM_SET_PRIMARY:
3074                 /* ADDIP Section 4.2.4
3075                  * If the address 0.0.0.0 or ::0 is provided, the receiver
3076                  * MAY mark the source address of the packet as its
3077                  * primary.
3078                  */
3079                 if (af->is_any(&addr))
3080                         memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));
3081 
3082                 peer = sctp_assoc_lookup_paddr(asoc, &addr);
3083                 if (!peer)
3084                         return SCTP_ERROR_DNS_FAILED;
3085 
3086                 sctp_assoc_set_primary(asoc, peer);
3087                 break;
3088         }
3089 
3090         return SCTP_ERROR_NO_ERROR;
3091 }
3092 
3093 /* Verify the ASCONF packet before we process it.  */
3094 int sctp_verify_asconf(const struct sctp_association *asoc,
3095                        struct sctp_paramhdr *param_hdr, void *chunk_end,
3096                        struct sctp_paramhdr **errp) {
3097         sctp_addip_param_t *asconf_param;
3098         union sctp_params param;
3099         int length, plen;
3100 
3101         param.v = (sctp_paramhdr_t *) param_hdr;
3102         while (param.v <= chunk_end - sizeof(sctp_paramhdr_t)) {
3103                 length = ntohs(param.p->length);
3104                 *errp = param.p;
3105 
3106                 if (param.v > chunk_end - length ||
3107                     length < sizeof(sctp_paramhdr_t))
3108                         return 0;
3109 
3110                 switch (param.p->type) {
3111                 case SCTP_PARAM_ADD_IP:
3112                 case SCTP_PARAM_DEL_IP:
3113                 case SCTP_PARAM_SET_PRIMARY:
3114                         asconf_param = (sctp_addip_param_t *)param.v;
3115                         plen = ntohs(asconf_param->param_hdr.length);
3116                         if (plen < sizeof(sctp_addip_param_t) +
3117                             sizeof(sctp_paramhdr_t))
3118                                 return 0;
3119                         break;
3120                 case SCTP_PARAM_SUCCESS_REPORT:
3121                 case SCTP_PARAM_ADAPTATION_LAYER_IND:
3122                         if (length != sizeof(sctp_addip_param_t))
3123                                 return 0;
3124 
3125                         break;
3126                 default:
3127                         break;
3128                 }
3129 
3130                 param.v += WORD_ROUND(length);
3131         }
3132 
3133         if (param.v != chunk_end)
3134                 return 0;
3135 
3136         return 1;
3137 }
3138 
3139 /* Process an incoming ASCONF chunk with the next expected serial no. and
3140  * return an ASCONF_ACK chunk to be sent in response.
3141  */
3142 struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
3143                                        struct sctp_chunk *asconf)
3144 {
3145         sctp_addiphdr_t         *hdr;
3146         union sctp_addr_param   *addr_param;
3147         sctp_addip_param_t      *asconf_param;
3148         struct sctp_chunk       *asconf_ack;
3149 
3150         __be16  err_code;
3151         int     length = 0;
3152         int     chunk_len;
3153         __u32   serial;
3154         int     all_param_pass = 1;
3155 
3156         chunk_len = ntohs(asconf->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
3157         hdr = (sctp_addiphdr_t *)asconf->skb->data;
3158         serial = ntohl(hdr->serial);
3159 
3160         /* Skip the addiphdr and store a pointer to address parameter.  */
3161         length = sizeof(sctp_addiphdr_t);
3162         addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3163         chunk_len -= length;
3164 
3165         /* Skip the address parameter and store a pointer to the first
3166          * asconf parameter.
3167          */
3168         length = ntohs(addr_param->p.length);
3169         asconf_param = (void *)addr_param + length;
3170         chunk_len -= length;
3171 
3172         /* create an ASCONF_ACK chunk.
3173          * Based on the definitions of parameters, we know that the size of
3174          * ASCONF_ACK parameters are less than or equal to the fourfold of ASCONF
3175          * parameters.
3176          */
3177         asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 4);
3178         if (!asconf_ack)
3179                 goto done;
3180 
3181         /* Process the TLVs contained within the ASCONF chunk. */
3182         while (chunk_len > 0) {
3183                 err_code = sctp_process_asconf_param(asoc, asconf,
3184                                                      asconf_param);
3185                 /* ADDIP 4.1 A7)
3186                  * If an error response is received for a TLV parameter,
3187                  * all TLVs with no response before the failed TLV are
3188                  * considered successful if not reported.  All TLVs after
3189                  * the failed response are considered unsuccessful unless
3190                  * a specific success indication is present for the parameter.
3191                  */
3192                 if (SCTP_ERROR_NO_ERROR != err_code)
3193                         all_param_pass = 0;
3194 
3195                 if (!all_param_pass)
3196                         sctp_add_asconf_response(asconf_ack,
3197                                                  asconf_param->crr_id, err_code,
3198                                                  asconf_param);
3199 
3200                 /* ADDIP 4.3 D11) When an endpoint receiving an ASCONF to add
3201                  * an IP address sends an 'Out of Resource' in its response, it
3202                  * MUST also fail any subsequent add or delete requests bundled
3203                  * in the ASCONF.
3204                  */
3205                 if (SCTP_ERROR_RSRC_LOW == err_code)
3206                         goto done;
3207 
3208                 /* Move to the next ASCONF param. */
3209                 length = ntohs(asconf_param->param_hdr.length);
3210                 asconf_param = (void *)asconf_param + length;
3211                 chunk_len -= length;
3212         }
3213 
3214 done:
3215         asoc->peer.addip_serial++;
3216 
3217         /* If we are sending a new ASCONF_ACK hold a reference to it in assoc
3218          * after freeing the reference to old asconf ack if any.
3219          */
3220         if (asconf_ack) {
3221                 sctp_chunk_hold(asconf_ack);
3222                 list_add_tail(&asconf_ack->transmitted_list,
3223                               &asoc->asconf_ack_list);
3224         }
3225 
3226         return asconf_ack;
3227 }
3228 
3229 /* Process a asconf parameter that is successfully acked. */
3230 static void sctp_asconf_param_success(struct sctp_association *asoc,
3231                                      sctp_addip_param_t *asconf_param)
3232 {
3233         struct sctp_af *af;
3234         union sctp_addr addr;
3235         struct sctp_bind_addr *bp = &asoc->base.bind_addr;
3236         union sctp_addr_param *addr_param;
3237         struct sctp_transport *transport;
3238         struct sctp_sockaddr_entry *saddr;
3239 
3240         addr_param = (void *)asconf_param + sizeof(sctp_addip_param_t);
3241 
3242         /* We have checked the packet before, so we do not check again. */
3243         af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3244         af->from_addr_param(&addr, addr_param, htons(bp->port), 0);
3245 
3246         switch (asconf_param->param_hdr.type) {
3247         case SCTP_PARAM_ADD_IP:
3248                 /* This is always done in BH context with a socket lock
3249                  * held, so the list can not change.
3250                  */
3251                 local_bh_disable();
3252                 list_for_each_entry(saddr, &bp->address_list, list) {
3253                         if (sctp_cmp_addr_exact(&saddr->a, &addr))
3254                                 saddr->state = SCTP_ADDR_SRC;
3255                 }
3256                 local_bh_enable();
3257                 list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3258                                 transports) {
3259                         dst_release(transport->dst);
3260                         transport->dst = NULL;
3261                 }
3262                 break;
3263         case SCTP_PARAM_DEL_IP:
3264                 local_bh_disable();
3265                 sctp_del_bind_addr(bp, &addr);
3266                 if (asoc->asconf_addr_del_pending != NULL &&
3267                     sctp_cmp_addr_exact(asoc->asconf_addr_del_pending, &addr)) {
3268                         kfree(asoc->asconf_addr_del_pending);
3269                         asoc->asconf_addr_del_pending = NULL;
3270                 }
3271                 local_bh_enable();
3272                 list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3273                                 transports) {
3274                         dst_release(transport->dst);
3275                         transport->dst = NULL;
3276                 }
3277                 break;
3278         default:
3279                 break;
3280         }
3281 }
3282 
3283 /* Get the corresponding ASCONF response error code from the ASCONF_ACK chunk
3284  * for the given asconf parameter.  If there is no response for this parameter,
3285  * return the error code based on the third argument 'no_err'.
3286  * ADDIP 4.1
3287  * A7) If an error response is received for a TLV parameter, all TLVs with no
3288  * response before the failed TLV are considered successful if not reported.
3289  * All TLVs after the failed response are considered unsuccessful unless a
3290  * specific success indication is present for the parameter.
3291  */
3292 static __be16 sctp_get_asconf_response(struct sctp_chunk *asconf_ack,
3293                                       sctp_addip_param_t *asconf_param,
3294                                       int no_err)
3295 {
3296         sctp_addip_param_t      *asconf_ack_param;
3297         sctp_errhdr_t           *err_param;
3298         int                     length;
3299         int                     asconf_ack_len;
3300         __be16                  err_code;
3301 
3302         if (no_err)
3303                 err_code = SCTP_ERROR_NO_ERROR;
3304         else
3305                 err_code = SCTP_ERROR_REQ_REFUSED;
3306 
3307         asconf_ack_len = ntohs(asconf_ack->chunk_hdr->length) -
3308                              sizeof(sctp_chunkhdr_t);
3309 
3310         /* Skip the addiphdr from the asconf_ack chunk and store a pointer to
3311          * the first asconf_ack parameter.
3312          */
3313         length = sizeof(sctp_addiphdr_t);
3314         asconf_ack_param = (sctp_addip_param_t *)(asconf_ack->skb->data +
3315                                                   length);
3316         asconf_ack_len -= length;
3317 
3318         while (asconf_ack_len > 0) {
3319                 if (asconf_ack_param->crr_id == asconf_param->crr_id) {
3320                         switch(asconf_ack_param->param_hdr.type) {
3321                         case SCTP_PARAM_SUCCESS_REPORT:
3322                                 return SCTP_ERROR_NO_ERROR;
3323                         case SCTP_PARAM_ERR_CAUSE:
3324                                 length = sizeof(sctp_addip_param_t);
3325                                 err_param = (void *)asconf_ack_param + length;
3326                                 asconf_ack_len -= length;
3327                                 if (asconf_ack_len > 0)
3328                                         return err_param->cause;
3329                                 else
3330                                         return SCTP_ERROR_INV_PARAM;
3331                                 break;
3332                         default:
3333                                 return SCTP_ERROR_INV_PARAM;
3334                         }
3335                 }
3336 
3337                 length = ntohs(asconf_ack_param->param_hdr.length);
3338                 asconf_ack_param = (void *)asconf_ack_param + length;
3339                 asconf_ack_len -= length;
3340         }
3341 
3342         return err_code;
3343 }
3344 
3345 /* Process an incoming ASCONF_ACK chunk against the cached last ASCONF chunk. */
3346 int sctp_process_asconf_ack(struct sctp_association *asoc,
3347                             struct sctp_chunk *asconf_ack)
3348 {
3349         struct sctp_chunk       *asconf = asoc->addip_last_asconf;
3350         union sctp_addr_param   *addr_param;
3351         sctp_addip_param_t      *asconf_param;
3352         int     length = 0;
3353         int     asconf_len = asconf->skb->len;
3354         int     all_param_pass = 0;
3355         int     no_err = 1;
3356         int     retval = 0;
3357         __be16  err_code = SCTP_ERROR_NO_ERROR;
3358 
3359         /* Skip the chunkhdr and addiphdr from the last asconf sent and store
3360          * a pointer to address parameter.
3361          */
3362         length = sizeof(sctp_addip_chunk_t);
3363         addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3364         asconf_len -= length;
3365 
3366         /* Skip the address parameter in the last asconf sent and store a
3367          * pointer to the first asconf parameter.
3368          */
3369         length = ntohs(addr_param->p.length);
3370         asconf_param = (void *)addr_param + length;
3371         asconf_len -= length;
3372 
3373         /* ADDIP 4.1
3374          * A8) If there is no response(s) to specific TLV parameter(s), and no
3375          * failures are indicated, then all request(s) are considered
3376          * successful.
3377          */
3378         if (asconf_ack->skb->len == sizeof(sctp_addiphdr_t))
3379                 all_param_pass = 1;
3380 
3381         /* Process the TLVs contained in the last sent ASCONF chunk. */
3382         while (asconf_len > 0) {
3383                 if (all_param_pass)
3384                         err_code = SCTP_ERROR_NO_ERROR;
3385                 else {
3386                         err_code = sctp_get_asconf_response(asconf_ack,
3387                                                             asconf_param,
3388                                                             no_err);
3389                         if (no_err && (SCTP_ERROR_NO_ERROR != err_code))
3390                                 no_err = 0;
3391                 }
3392 
3393                 switch (err_code) {
3394                 case SCTP_ERROR_NO_ERROR:
3395                         sctp_asconf_param_success(asoc, asconf_param);
3396                         break;
3397 
3398                 case SCTP_ERROR_RSRC_LOW:
3399                         retval = 1;
3400                         break;
3401 
3402                 case SCTP_ERROR_UNKNOWN_PARAM:
3403                         /* Disable sending this type of asconf parameter in
3404                          * future.
3405                          */
3406                         asoc->peer.addip_disabled_mask |=
3407                                 asconf_param->param_hdr.type;
3408                         break;
3409 
3410                 case SCTP_ERROR_REQ_REFUSED:
3411                 case SCTP_ERROR_DEL_LAST_IP:
3412                 case SCTP_ERROR_DEL_SRC_IP:
3413                 default:
3414                          break;
3415                 }
3416 
3417                 /* Skip the processed asconf parameter and move to the next
3418                  * one.
3419                  */
3420                 length = ntohs(asconf_param->param_hdr.length);
3421                 asconf_param = (void *)asconf_param + length;
3422                 asconf_len -= length;
3423         }
3424 
3425         if (no_err && asoc->src_out_of_asoc_ok) {
3426                 asoc->src_out_of_asoc_ok = 0;
3427                 sctp_transport_immediate_rtx(asoc->peer.primary_path);
3428         }
3429 
3430         /* Free the cached last sent asconf chunk. */
3431         list_del_init(&asconf->transmitted_list);
3432         sctp_chunk_free(asconf);
3433         asoc->addip_last_asconf = NULL;
3434 
3435         return retval;
3436 }
3437 
3438 /* Make a FWD TSN chunk. */
3439 struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
3440                                     __u32 new_cum_tsn, size_t nstreams,
3441                                     struct sctp_fwdtsn_skip *skiplist)
3442 {
3443         struct sctp_chunk *retval = NULL;
3444         struct sctp_fwdtsn_hdr ftsn_hdr;
3445         struct sctp_fwdtsn_skip skip;
3446         size_t hint;
3447         int i;
3448 
3449         hint = (nstreams + 1) * sizeof(__u32);
3450 
3451         retval = sctp_make_chunk(asoc, SCTP_CID_FWD_TSN, 0, hint);
3452 
3453         if (!retval)
3454                 return NULL;
3455 
3456         ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
3457         retval->subh.fwdtsn_hdr =
3458                 sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
3459 
3460         for (i = 0; i < nstreams; i++) {
3461                 skip.stream = skiplist[i].stream;
3462                 skip.ssn = skiplist[i].ssn;
3463                 sctp_addto_chunk(retval, sizeof(skip), &skip);
3464         }
3465 
3466         return retval;
3467 }
3468 

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