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
  71SCTP_STATIC
  72struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc,
  73                                   __u8 type, __u8 flags, int paylen);
  74static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
  75                                        const struct sctp_association *asoc,
  76                                        const struct sctp_chunk *init_chunk,
  77                                        int *cookie_len,
  78                                        const __u8 *raw_addrs, int addrs_len);
  79static int sctp_process_param(struct sctp_association *asoc,
  80                              union sctp_params param,
  81                              const union sctp_addr *peer_addr,
  82                              gfp_t gfp);
  83static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
  84                              const void *data);
  85
  86/* What was the inbound interface for this chunk? */
  87int sctp_chunk_iif(const struct sctp_chunk *chunk)
  88{
  89        struct sctp_af *af;
  90        int iif = 0;
  91
  92        af = sctp_get_af_specific(ipver2af(ip_hdr(chunk->skb)->version));
  93        if (af)
  94                iif = af->skb_iif(chunk->skb);
  95
  96        return iif;
  97}
  98
  99/* RFC 2960 3.3.2 Initiation (INIT) (1)
 100 *
 101 * Note 2: The ECN capable field is reserved for future use of
 102 * Explicit Congestion Notification.
 103 */
 104static const struct sctp_paramhdr ecap_param = {
 105        SCTP_PARAM_ECN_CAPABLE,
 106        cpu_to_be16(sizeof(struct sctp_paramhdr)),
 107};
 108static const struct sctp_paramhdr prsctp_param = {
 109        SCTP_PARAM_FWD_TSN_SUPPORT,
 110        cpu_to_be16(sizeof(struct sctp_paramhdr)),
 111};
 112
 113/* A helper to initialize an op error inside a
 114 * provided chunk, as most cause codes will be embedded inside an
 115 * abort chunk.
 116 */
 117void  sctp_init_cause(struct sctp_chunk *chunk, __be16 cause_code,
 118                      size_t paylen)
 119{
 120        sctp_errhdr_t err;
 121        __u16 len;
 122
 123        /* Cause code constants are now defined in network order.  */
 124        err.cause = cause_code;
 125        len = sizeof(sctp_errhdr_t) + paylen;
 126        err.length  = htons(len);
 127        chunk->subh.err_hdr = sctp_addto_chunk(chunk, sizeof(sctp_errhdr_t), &err);
 128}
 129
 130/* A helper to initialize an op error inside a
 131 * provided chunk, as most cause codes will be embedded inside an
 132 * abort chunk.  Differs from sctp_init_cause in that it won't oops
 133 * if there isn't enough space in the op error chunk
 134 */
 135static int sctp_init_cause_fixed(struct sctp_chunk *chunk, __be16 cause_code,
 136                      size_t paylen)
 137{
 138        sctp_errhdr_t err;
 139        __u16 len;
 140
 141        /* Cause code constants are now defined in network order.  */
 142        err.cause = cause_code;
 143        len = sizeof(sctp_errhdr_t) + paylen;
 144        err.length  = htons(len);
 145
 146        if (skb_tailroom(chunk->skb) < len)
 147                return -ENOSPC;
 148        chunk->subh.err_hdr = sctp_addto_chunk_fixed(chunk,
 149                                                     sizeof(sctp_errhdr_t),
 150                                                     &err);
 151        return 0;
 152}
 153/* 3.3.2 Initiation (INIT) (1)
 154 *
 155 * This chunk is used to initiate a SCTP association between two
 156 * endpoints. The format of the INIT chunk is shown below:
 157 *
 158 *     0                   1                   2                   3
 159 *     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
 160 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 161 *    |   Type = 1    |  Chunk Flags  |      Chunk Length             |
 162 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 163 *    |                         Initiate Tag                          |
 164 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 165 *    |           Advertised Receiver Window Credit (a_rwnd)          |
 166 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 167 *    |  Number of Outbound Streams   |  Number of Inbound Streams    |
 168 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 169 *    |                          Initial TSN                          |
 170 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 171 *    \                                                               \
 172 *    /              Optional/Variable-Length Parameters              /
 173 *    \                                                               \
 174 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 175 *
 176 *
 177 * The INIT chunk contains the following parameters. Unless otherwise
 178 * noted, each parameter MUST only be included once in the INIT chunk.
 179 *
 180 * Fixed Parameters                     Status
 181 * ----------------------------------------------
 182 * Initiate Tag                        Mandatory
 183 * Advertised Receiver Window Credit   Mandatory
 184 * Number of Outbound Streams          Mandatory
 185 * Number of Inbound Streams           Mandatory
 186 * Initial TSN                         Mandatory
 187 *
 188 * Variable Parameters                  Status     Type Value
 189 * -------------------------------------------------------------
 190 * IPv4 Address (Note 1)               Optional    5
 191 * IPv6 Address (Note 1)               Optional    6
 192 * Cookie Preservative                 Optional    9
 193 * Reserved for ECN Capable (Note 2)   Optional    32768 (0x8000)
 194 * Host Name Address (Note 3)          Optional    11
 195 * Supported Address Types (Note 4)    Optional    12
 196 */
 197struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc,
 198                             const struct sctp_bind_addr *bp,
 199                             gfp_t gfp, int vparam_len)
 200{
 201        struct net *net = sock_net(asoc->base.sk);
 202        sctp_inithdr_t init;
 203        union sctp_params addrs;
 204        size_t chunksize;
 205        struct sctp_chunk *retval = NULL;
 206        int num_types, addrs_len = 0;
 207        struct sctp_sock *sp;
 208        sctp_supported_addrs_param_t sat;
 209        __be16 types[2];
 210        sctp_adaptation_ind_param_t aiparam;
 211        sctp_supported_ext_param_t ext_param;
 212        int num_ext = 0;
 213        __u8 extensions[3];
 214        sctp_paramhdr_t *auth_chunks = NULL,
 215                        *auth_hmacs = NULL;
 216
 217        /* RFC 2960 3.3.2 Initiation (INIT) (1)
 218         *
 219         * Note 1: The INIT chunks can contain multiple addresses that
 220         * can be IPv4 and/or IPv6 in any combination.
 221         */
 222        retval = NULL;
 223
 224        /* Convert the provided bind address list to raw format. */
 225        addrs = sctp_bind_addrs_to_raw(bp, &addrs_len, gfp);
 226
 227        init.init_tag              = htonl(asoc->c.my_vtag);
 228        init.a_rwnd                = htonl(asoc->rwnd);
 229        init.num_outbound_streams  = htons(asoc->c.sinit_num_ostreams);
 230        init.num_inbound_streams   = htons(asoc->c.sinit_max_instreams);
 231        init.initial_tsn           = htonl(asoc->c.initial_tsn);
 232
 233        /* How many address types are needed? */
 234        sp = sctp_sk(asoc->base.sk);
 235        num_types = sp->pf->supported_addrs(sp, types);
 236
 237        chunksize = sizeof(init) + addrs_len;
 238        chunksize += WORD_ROUND(SCTP_SAT_LEN(num_types));
 239        chunksize += sizeof(ecap_param);
 240
 241        if (net->sctp.prsctp_enable)
 242                chunksize += sizeof(prsctp_param);
 243
 244        /* ADDIP: Section 4.2.7:
 245         *  An implementation supporting this extension [ADDIP] MUST list
 246         *  the ASCONF,the ASCONF-ACK, and the AUTH  chunks in its INIT and
 247         *  INIT-ACK parameters.
 248         */
 249        if (net->sctp.addip_enable) {
 250                extensions[num_ext] = SCTP_CID_ASCONF;
 251                extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
 252                num_ext += 2;
 253        }
 254
 255        if (sp->adaptation_ind)
 256                chunksize += sizeof(aiparam);
 257
 258        chunksize += vparam_len;
 259
 260        /* Account for AUTH related parameters */
 261        if (net->sctp.auth_enable) {
 262                /* Add random parameter length*/
 263                chunksize += sizeof(asoc->c.auth_random);
 264
 265                /* Add HMACS parameter length if any were defined */
 266                auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
 267                if (auth_hmacs->length)
 268                        chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
 269                else
 270                        auth_hmacs = NULL;
 271
 272                /* Add CHUNKS parameter length */
 273                auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
 274                if (auth_chunks->length)
 275                        chunksize += WORD_ROUND(ntohs(auth_chunks->length));
 276                else
 277                        auth_chunks = NULL;
 278
 279                extensions[num_ext] = SCTP_CID_AUTH;
 280                num_ext += 1;
 281        }
 282
 283        /* If we have any extensions to report, account for that */
 284        if (num_ext)
 285                chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) +
 286                                        num_ext);
 287
 288        /* RFC 2960 3.3.2 Initiation (INIT) (1)
 289         *
 290         * Note 3: An INIT chunk MUST NOT contain more than one Host
 291         * Name address parameter. Moreover, the sender of the INIT
 292         * MUST NOT combine any other address types with the Host Name
 293         * address in the INIT. The receiver of INIT MUST ignore any
 294         * other address types if the Host Name address parameter is
 295         * present in the received INIT chunk.
 296         *
 297         * PLEASE DO NOT FIXME [This version does not support Host Name.]
 298         */
 299
 300        retval = sctp_make_chunk(asoc, SCTP_CID_INIT, 0, chunksize);
 301        if (!retval)
 302                goto nodata;
 303
 304        retval->subh.init_hdr =
 305                sctp_addto_chunk(retval, sizeof(init), &init);
 306        retval->param_hdr.v =
 307                sctp_addto_chunk(retval, addrs_len, addrs.v);
 308
 309        /* RFC 2960 3.3.2 Initiation (INIT) (1)
 310         *
 311         * Note 4: This parameter, when present, specifies all the
 312         * address types the sending endpoint can support. The absence
 313         * of this parameter indicates that the sending endpoint can
 314         * support any address type.
 315         */
 316        sat.param_hdr.type = SCTP_PARAM_SUPPORTED_ADDRESS_TYPES;
 317        sat.param_hdr.length = htons(SCTP_SAT_LEN(num_types));
 318        sctp_addto_chunk(retval, sizeof(sat), &sat);
 319        sctp_addto_chunk(retval, num_types * sizeof(__u16), &types);
 320
 321        sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
 322
 323        /* Add the supported extensions parameter.  Be nice and add this
 324         * fist before addiding the parameters for the extensions themselves
 325         */
 326        if (num_ext) {
 327                ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
 328                ext_param.param_hdr.length =
 329                            htons(sizeof(sctp_supported_ext_param_t) + num_ext);
 330                sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
 331                                &ext_param);
 332                sctp_addto_param(retval, num_ext, extensions);
 333        }
 334
 335        if (net->sctp.prsctp_enable)
 336                sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
 337
 338        if (sp->adaptation_ind) {
 339                aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
 340                aiparam.param_hdr.length = htons(sizeof(aiparam));
 341                aiparam.adaptation_ind = htonl(sp->adaptation_ind);
 342                sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
 343        }
 344
 345        /* Add SCTP-AUTH chunks to the parameter list */
 346        if (net->sctp.auth_enable) {
 347                sctp_addto_chunk(retval, sizeof(asoc->c.auth_random),
 348                                 asoc->c.auth_random);
 349                if (auth_hmacs)
 350                        sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
 351                                        auth_hmacs);
 352                if (auth_chunks)
 353                        sctp_addto_chunk(retval, ntohs(auth_chunks->length),
 354                                        auth_chunks);
 355        }
 356nodata:
 357        kfree(addrs.v);
 358        return retval;
 359}
 360
 361struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc,
 362                                 const struct sctp_chunk *chunk,
 363                                 gfp_t gfp, int unkparam_len)
 364{
 365        sctp_inithdr_t initack;
 366        struct sctp_chunk *retval;
 367        union sctp_params addrs;
 368        struct sctp_sock *sp;
 369        int addrs_len;
 370        sctp_cookie_param_t *cookie;
 371        int cookie_len;
 372        size_t chunksize;
 373        sctp_adaptation_ind_param_t aiparam;
 374        sctp_supported_ext_param_t ext_param;
 375        int num_ext = 0;
 376        __u8 extensions[3];
 377        sctp_paramhdr_t *auth_chunks = NULL,
 378                        *auth_hmacs = NULL,
 379                        *auth_random = NULL;
 380
 381        retval = NULL;
 382
 383        /* Note: there may be no addresses to embed. */
 384        addrs = sctp_bind_addrs_to_raw(&asoc->base.bind_addr, &addrs_len, gfp);
 385
 386        initack.init_tag                = htonl(asoc->c.my_vtag);
 387        initack.a_rwnd                  = htonl(asoc->rwnd);
 388        initack.num_outbound_streams    = htons(asoc->c.sinit_num_ostreams);
 389        initack.num_inbound_streams     = htons(asoc->c.sinit_max_instreams);
 390        initack.initial_tsn             = htonl(asoc->c.initial_tsn);
 391
 392        /* FIXME:  We really ought to build the cookie right
 393         * into the packet instead of allocating more fresh memory.
 394         */
 395        cookie = sctp_pack_cookie(asoc->ep, asoc, chunk, &cookie_len,
 396                                  addrs.v, addrs_len);
 397        if (!cookie)
 398                goto nomem_cookie;
 399
 400        /* Calculate the total size of allocation, include the reserved
 401         * space for reporting unknown parameters if it is specified.
 402         */
 403        sp = sctp_sk(asoc->base.sk);
 404        chunksize = sizeof(initack) + addrs_len + cookie_len + unkparam_len;
 405
 406        /* Tell peer that we'll do ECN only if peer advertised such cap.  */
 407        if (asoc->peer.ecn_capable)
 408                chunksize += sizeof(ecap_param);
 409
 410        if (asoc->peer.prsctp_capable)
 411                chunksize += sizeof(prsctp_param);
 412
 413        if (asoc->peer.asconf_capable) {
 414                extensions[num_ext] = SCTP_CID_ASCONF;
 415                extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
 416                num_ext += 2;
 417        }
 418
 419        if (sp->adaptation_ind)
 420                chunksize += sizeof(aiparam);
 421
 422        if (asoc->peer.auth_capable) {
 423                auth_random = (sctp_paramhdr_t *)asoc->c.auth_random;
 424                chunksize += ntohs(auth_random->length);
 425
 426                auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
 427                if (auth_hmacs->length)
 428                        chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
 429                else
 430                        auth_hmacs = NULL;
 431
 432                auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
 433                if (auth_chunks->length)
 434                        chunksize += WORD_ROUND(ntohs(auth_chunks->length));
 435                else
 436                        auth_chunks = NULL;
 437
 438                extensions[num_ext] = SCTP_CID_AUTH;
 439                num_ext += 1;
 440        }
 441
 442        if (num_ext)
 443                chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) +
 444                                        num_ext);
 445
 446        /* Now allocate and fill out the chunk.  */
 447        retval = sctp_make_chunk(asoc, SCTP_CID_INIT_ACK, 0, chunksize);
 448        if (!retval)
 449                goto nomem_chunk;
 450
 451        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
 452         *
 453         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 454         * HEARTBEAT ACK, * etc.) to the same destination transport
 455         * address from which it received the DATA or control chunk
 456         * to which it is replying.
 457         *
 458         * [INIT ACK back to where the INIT came from.]
 459         */
 460        retval->transport = chunk->transport;
 461
 462        retval->subh.init_hdr =
 463                sctp_addto_chunk(retval, sizeof(initack), &initack);
 464        retval->param_hdr.v = sctp_addto_chunk(retval, addrs_len, addrs.v);
 465        sctp_addto_chunk(retval, cookie_len, cookie);
 466        if (asoc->peer.ecn_capable)
 467                sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
 468        if (num_ext) {
 469                ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
 470                ext_param.param_hdr.length =
 471                            htons(sizeof(sctp_supported_ext_param_t) + num_ext);
 472                sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
 473                                 &ext_param);
 474                sctp_addto_param(retval, num_ext, extensions);
 475        }
 476        if (asoc->peer.prsctp_capable)
 477                sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
 478
 479        if (sp->adaptation_ind) {
 480                aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
 481                aiparam.param_hdr.length = htons(sizeof(aiparam));
 482                aiparam.adaptation_ind = htonl(sp->adaptation_ind);
 483                sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
 484        }
 485
 486        if (asoc->peer.auth_capable) {
 487                sctp_addto_chunk(retval, ntohs(auth_random->length),
 488                                 auth_random);
 489                if (auth_hmacs)
 490                        sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
 491                                        auth_hmacs);
 492                if (auth_chunks)
 493                        sctp_addto_chunk(retval, ntohs(auth_chunks->length),
 494                                        auth_chunks);
 495        }
 496
 497        /* We need to remove the const qualifier at this point.  */
 498        retval->asoc = (struct sctp_association *) asoc;
 499
 500nomem_chunk:
 501        kfree(cookie);
 502nomem_cookie:
 503        kfree(addrs.v);
 504        return retval;
 505}
 506
 507/* 3.3.11 Cookie Echo (COOKIE ECHO) (10):
 508 *
 509 * This chunk is used only during the initialization of an association.
 510 * It is sent by the initiator of an association to its peer to complete
 511 * the initialization process. This chunk MUST precede any DATA chunk
 512 * sent within the association, but MAY be bundled with one or more DATA
 513 * chunks in the same packet.
 514 *
 515 *      0                   1                   2                   3
 516 *      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
 517 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 518 *     |   Type = 10   |Chunk  Flags   |         Length                |
 519 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 520 *     /                     Cookie                                    /
 521 *     \                                                               \
 522 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 523 *
 524 * Chunk Flags: 8 bit
 525 *
 526 *   Set to zero on transmit and ignored on receipt.
 527 *
 528 * Length: 16 bits (unsigned integer)
 529 *
 530 *   Set to the size of the chunk in bytes, including the 4 bytes of
 531 *   the chunk header and the size of the Cookie.
 532 *
 533 * Cookie: variable size
 534 *
 535 *   This field must contain the exact cookie received in the
 536 *   State Cookie parameter from the previous INIT ACK.
 537 *
 538 *   An implementation SHOULD make the cookie as small as possible
 539 *   to insure interoperability.
 540 */
 541struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *asoc,
 542                                    const struct sctp_chunk *chunk)
 543{
 544        struct sctp_chunk *retval;
 545        void *cookie;
 546        int cookie_len;
 547
 548        cookie = asoc->peer.cookie;
 549        cookie_len = asoc->peer.cookie_len;
 550
 551        /* Build a cookie echo chunk.  */
 552        retval = sctp_make_chunk(asoc, SCTP_CID_COOKIE_ECHO, 0, cookie_len);
 553        if (!retval)
 554                goto nodata;
 555        retval->subh.cookie_hdr =
 556                sctp_addto_chunk(retval, cookie_len, cookie);
 557
 558        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
 559         *
 560         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 561         * HEARTBEAT ACK, * etc.) to the same destination transport
 562         * address from which it * received the DATA or control chunk
 563         * to which it is replying.
 564         *
 565         * [COOKIE ECHO back to where the INIT ACK came from.]
 566         */
 567        if (chunk)
 568                retval->transport = chunk->transport;
 569
 570nodata:
 571        return retval;
 572}
 573
 574/* 3.3.12 Cookie Acknowledgement (COOKIE ACK) (11):
 575 *
 576 * This chunk is used only during the initialization of an
 577 * association.  It is used to acknowledge the receipt of a COOKIE
 578 * ECHO chunk.  This chunk MUST precede any DATA or SACK chunk sent
 579 * within the association, but MAY be bundled with one or more DATA
 580 * chunks or SACK chunk in the same SCTP packet.
 581 *
 582 *      0                   1                   2                   3
 583 *      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
 584 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 585 *     |   Type = 11   |Chunk  Flags   |     Length = 4                |
 586 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 587 *
 588 * Chunk Flags: 8 bits
 589 *
 590 *   Set to zero on transmit and ignored on receipt.
 591 */
 592struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *asoc,
 593                                   const struct sctp_chunk *chunk)
 594{
 595        struct sctp_chunk *retval;
 596
 597        retval = sctp_make_chunk(asoc, SCTP_CID_COOKIE_ACK, 0, 0);
 598
 599        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
 600         *
 601         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 602         * HEARTBEAT ACK, * etc.) to the same destination transport
 603         * address from which it * received the DATA or control chunk
 604         * to which it is replying.
 605         *
 606         * [COOKIE ACK back to where the COOKIE ECHO came from.]
 607         */
 608        if (retval && chunk)
 609                retval->transport = chunk->transport;
 610
 611        return retval;
 612}
 613
 614/*
 615 *  Appendix A: Explicit Congestion Notification:
 616 *  CWR:
 617 *
 618 *  RFC 2481 details a specific bit for a sender to send in the header of
 619 *  its next outbound TCP segment to indicate to its peer that it has
 620 *  reduced its congestion window.  This is termed the CWR bit.  For
 621 *  SCTP the same indication is made by including the CWR chunk.
 622 *  This chunk contains one data element, i.e. the TSN number that
 623 *  was sent in the ECNE chunk.  This element represents the lowest
 624 *  TSN number in the datagram that was originally marked with the
 625 *  CE bit.
 626 *
 627 *     0                   1                   2                   3
 628 *     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
 629 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 630 *    | Chunk Type=13 | Flags=00000000|    Chunk Length = 8           |
 631 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 632 *    |                      Lowest TSN Number                        |
 633 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 634 *
 635 *     Note: The CWR is considered a Control chunk.
 636 */
 637struct sctp_chunk *sctp_make_cwr(const struct sctp_association *asoc,
 638                            const __u32 lowest_tsn,
 639                            const struct sctp_chunk *chunk)
 640{
 641        struct sctp_chunk *retval;
 642        sctp_cwrhdr_t cwr;
 643
 644        cwr.lowest_tsn = htonl(lowest_tsn);
 645        retval = sctp_make_chunk(asoc, SCTP_CID_ECN_CWR, 0,
 646                                 sizeof(sctp_cwrhdr_t));
 647
 648        if (!retval)
 649                goto nodata;
 650
 651        retval->subh.ecn_cwr_hdr =
 652                sctp_addto_chunk(retval, sizeof(cwr), &cwr);
 653
 654        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
 655         *
 656         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 657         * HEARTBEAT ACK, * etc.) to the same destination transport
 658         * address from which it * received the DATA or control chunk
 659         * to which it is replying.
 660         *
 661         * [Report a reduced congestion window back to where the ECNE
 662         * came from.]
 663         */
 664        if (chunk)
 665                retval->transport = chunk->transport;
 666
 667nodata:
 668        return retval;
 669}
 670
 671/* Make an ECNE chunk.  This is a congestion experienced report.  */
 672struct sctp_chunk *sctp_make_ecne(const struct sctp_association *asoc,
 673                             const __u32 lowest_tsn)
 674{
 675        struct sctp_chunk *retval;
 676        sctp_ecnehdr_t ecne;
 677
 678        ecne.lowest_tsn = htonl(lowest_tsn);
 679        retval = sctp_make_chunk(asoc, SCTP_CID_ECN_ECNE, 0,
 680                                 sizeof(sctp_ecnehdr_t));
 681        if (!retval)
 682                goto nodata;
 683        retval->subh.ecne_hdr =
 684                sctp_addto_chunk(retval, sizeof(ecne), &ecne);
 685
 686nodata:
 687        return retval;
 688}
 689
 690/* Make a DATA chunk for the given association from the provided
 691 * parameters.  However, do not populate the data payload.
 692 */
 693struct sctp_chunk *sctp_make_datafrag_empty(struct sctp_association *asoc,
 694                                       const struct sctp_sndrcvinfo *sinfo,
 695                                       int data_len, __u8 flags, __u16 ssn)
 696{
 697        struct sctp_chunk *retval;
 698        struct sctp_datahdr dp;
 699        int chunk_len;
 700
 701        /* We assign the TSN as LATE as possible, not here when
 702         * creating the chunk.
 703         */
 704        dp.tsn = 0;
 705        dp.stream = htons(sinfo->sinfo_stream);
 706        dp.ppid   = sinfo->sinfo_ppid;
 707
 708        /* Set the flags for an unordered send.  */
 709        if (sinfo->sinfo_flags & SCTP_UNORDERED) {
 710                flags |= SCTP_DATA_UNORDERED;
 711                dp.ssn = 0;
 712        } else
 713                dp.ssn = htons(ssn);
 714
 715        chunk_len = sizeof(dp) + data_len;
 716        retval = sctp_make_chunk(asoc, SCTP_CID_DATA, flags, chunk_len);
 717        if (!retval)
 718                goto nodata;
 719
 720        retval->subh.data_hdr = sctp_addto_chunk(retval, sizeof(dp), &dp);
 721        memcpy(&retval->sinfo, sinfo, sizeof(struct sctp_sndrcvinfo));
 722
 723nodata:
 724        return retval;
 725}
 726
 727/* Create a selective ackowledgement (SACK) for the given
 728 * association.  This reports on which TSN's we've seen to date,
 729 * including duplicates and gaps.
 730 */
 731struct sctp_chunk *sctp_make_sack(const struct sctp_association *asoc)
 732{
 733        struct sctp_chunk *retval;
 734        struct sctp_sackhdr sack;
 735        int len;
 736        __u32 ctsn;
 737        __u16 num_gabs, num_dup_tsns;
 738        struct sctp_association *aptr = (struct sctp_association *)asoc;
 739        struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
 740        struct sctp_gap_ack_block gabs[SCTP_MAX_GABS];
 741        struct sctp_transport *trans;
 742
 743        memset(gabs, 0, sizeof(gabs));
 744        ctsn = sctp_tsnmap_get_ctsn(map);
 745        SCTP_DEBUG_PRINTK("sackCTSNAck sent:  0x%x.\n", 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                sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns,
 809                                 sctp_tsnmap_get_dups(map));
 810
 811        /* Once we have a sack generated, check to see what our sack
 812         * generation is, if its 0, reset the transports to 0, and reset
 813         * the association generation to 1
 814         *
 815         * The idea is that zero is never used as a valid generation for the
 816         * association so no transport will match after a wrap event like this,
 817         * Until the next sack
 818         */
 819        if (++aptr->peer.sack_generation == 0) {
 820                list_for_each_entry(trans, &asoc->peer.transport_addr_list,
 821                                    transports)
 822                        trans->sack_generation = 0;
 823                aptr->peer.sack_generation = 1;
 824        }
 825nodata:
 826        return retval;
 827}
 828
 829/* Make a SHUTDOWN chunk. */
 830struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
 831                                      const struct sctp_chunk *chunk)
 832{
 833        struct sctp_chunk *retval;
 834        sctp_shutdownhdr_t shut;
 835        __u32 ctsn;
 836
 837        ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
 838        shut.cum_tsn_ack = htonl(ctsn);
 839
 840        retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN, 0,
 841                                 sizeof(sctp_shutdownhdr_t));
 842        if (!retval)
 843                goto nodata;
 844
 845        retval->subh.shutdown_hdr =
 846                sctp_addto_chunk(retval, sizeof(shut), &shut);
 847
 848        if (chunk)
 849                retval->transport = chunk->transport;
 850nodata:
 851        return retval;
 852}
 853
 854struct sctp_chunk *sctp_make_shutdown_ack(const struct sctp_association *asoc,
 855                                     const struct sctp_chunk *chunk)
 856{
 857        struct sctp_chunk *retval;
 858
 859        retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN_ACK, 0, 0);
 860
 861        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
 862         *
 863         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 864         * HEARTBEAT ACK, * etc.) to the same destination transport
 865         * address from which it * received the DATA or control chunk
 866         * to which it is replying.
 867         *
 868         * [ACK back to where the SHUTDOWN came from.]
 869         */
 870        if (retval && chunk)
 871                retval->transport = chunk->transport;
 872
 873        return retval;
 874}
 875
 876struct sctp_chunk *sctp_make_shutdown_complete(
 877        const struct sctp_association *asoc,
 878        const struct sctp_chunk *chunk)
 879{
 880        struct sctp_chunk *retval;
 881        __u8 flags = 0;
 882
 883        /* Set the T-bit if we have no association (vtag will be
 884         * reflected)
 885         */
 886        flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;
 887
 888        retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags, 0);
 889
 890        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
 891         *
 892         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 893         * HEARTBEAT ACK, * etc.) to the same destination transport
 894         * address from which it * received the DATA or control chunk
 895         * to which it is replying.
 896         *
 897         * [Report SHUTDOWN COMPLETE back to where the SHUTDOWN ACK
 898         * came from.]
 899         */
 900        if (retval && chunk)
 901                retval->transport = chunk->transport;
 902
 903        return retval;
 904}
 905
 906/* Create an ABORT.  Note that we set the T bit if we have no
 907 * association, except when responding to an INIT (sctpimpguide 2.41).
 908 */
 909struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc,
 910                              const struct sctp_chunk *chunk,
 911                              const size_t hint)
 912{
 913        struct sctp_chunk *retval;
 914        __u8 flags = 0;
 915
 916        /* Set the T-bit if we have no association and 'chunk' is not
 917         * an INIT (vtag will be reflected).
 918         */
 919        if (!asoc) {
 920                if (chunk && chunk->chunk_hdr &&
 921                    chunk->chunk_hdr->type == SCTP_CID_INIT)
 922                        flags = 0;
 923                else
 924                        flags = SCTP_CHUNK_FLAG_T;
 925        }
 926
 927        retval = sctp_make_chunk(asoc, SCTP_CID_ABORT, flags, hint);
 928
 929        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
 930         *
 931         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 932         * HEARTBEAT ACK, * etc.) to the same destination transport
 933         * address from which it * received the DATA or control chunk
 934         * to which it is replying.
 935         *
 936         * [ABORT back to where the offender came from.]
 937         */
 938        if (retval && chunk)
 939                retval->transport = chunk->transport;
 940
 941        return retval;
 942}
 943
 944/* Helper to create ABORT with a NO_USER_DATA error.  */
 945struct sctp_chunk *sctp_make_abort_no_data(
 946        const struct sctp_association *asoc,
 947        const struct sctp_chunk *chunk, __u32 tsn)
 948{
 949        struct sctp_chunk *retval;
 950        __be32 payload;
 951
 952        retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t)
 953                                 + sizeof(tsn));
 954
 955        if (!retval)
 956                goto no_mem;
 957
 958        /* Put the tsn back into network byte order.  */
 959        payload = htonl(tsn);
 960        sctp_init_cause(retval, SCTP_ERROR_NO_DATA, sizeof(payload));
 961        sctp_addto_chunk(retval, sizeof(payload), (const void *)&payload);
 962
 963        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
 964         *
 965         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 966         * HEARTBEAT ACK, * etc.) to the same destination transport
 967         * address from which it * received the DATA or control chunk
 968         * to which it is replying.
 969         *
 970         * [ABORT back to where the offender came from.]
 971         */
 972        if (chunk)
 973                retval->transport = chunk->transport;
 974
 975no_mem:
 976        return retval;
 977}
 978
 979/* Helper to create ABORT with a SCTP_ERROR_USER_ABORT error.  */
 980struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *asoc,
 981                                        const struct msghdr *msg,
 982                                        size_t paylen)
 983{
 984        struct sctp_chunk *retval;
 985        void *payload = NULL;
 986        int err;
 987
 988        retval = sctp_make_abort(asoc, NULL, sizeof(sctp_errhdr_t) + paylen);
 989        if (!retval)
 990                goto err_chunk;
 991
 992        if (paylen) {
 993                /* Put the msg_iov together into payload.  */
 994                payload = kmalloc(paylen, GFP_KERNEL);
 995                if (!payload)
 996                        goto err_payload;
 997
 998                err = memcpy_fromiovec(payload, msg->msg_iov, paylen);
 999                if (err < 0)
1000                        goto err_copy;
1001        }
1002
1003        sctp_init_cause(retval, SCTP_ERROR_USER_ABORT, paylen);
1004        sctp_addto_chunk(retval, paylen, payload);
1005
1006        if (paylen)
1007                kfree(payload);
1008
1009        return retval;
1010
1011err_copy:
1012        kfree(payload);
1013err_payload:
1014        sctp_chunk_free(retval);
1015        retval = NULL;
1016err_chunk:
1017        return retval;
1018}
1019
1020/* Append bytes to the end of a parameter.  Will panic if chunk is not big
1021 * enough.
1022 */
1023static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
1024                              const void *data)
1025{
1026        void *target;
1027        int chunklen = ntohs(chunk->chunk_hdr->length);
1028
1029        target = skb_put(chunk->skb, len);
1030
1031        if (data)
1032                memcpy(target, data, len);
1033        else
1034                memset(target, 0, len);
1035
1036        /* Adjust the chunk length field.  */
1037        chunk->chunk_hdr->length = htons(chunklen + len);
1038        chunk->chunk_end = skb_tail_pointer(chunk->skb);
1039
1040        return target;
1041}
1042
1043/* Make an ABORT chunk with a PROTOCOL VIOLATION cause code. */
1044struct sctp_chunk *sctp_make_abort_violation(
1045        const struct sctp_association *asoc,
1046        const struct sctp_chunk *chunk,
1047        const __u8   *payload,
1048        const size_t paylen)
1049{
1050        struct sctp_chunk  *retval;
1051        struct sctp_paramhdr phdr;
1052
1053        retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t) + paylen
1054                                        + sizeof(sctp_paramhdr_t));
1055        if (!retval)
1056                goto end;
1057
1058        sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, paylen
1059                                        + sizeof(sctp_paramhdr_t));
1060
1061        phdr.type = htons(chunk->chunk_hdr->type);
1062        phdr.length = chunk->chunk_hdr->length;
1063        sctp_addto_chunk(retval, paylen, payload);
1064        sctp_addto_param(retval, sizeof(sctp_paramhdr_t), &phdr);
1065
1066end:
1067        return retval;
1068}
1069
1070struct sctp_chunk *sctp_make_violation_paramlen(
1071        const struct sctp_association *asoc,
1072        const struct sctp_chunk *chunk,
1073        struct sctp_paramhdr *param)
1074{
1075        struct sctp_chunk *retval;
1076        static const char error[] = "The following parameter had invalid length:";
1077        size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t) +
1078                                sizeof(sctp_paramhdr_t);
1079
1080        retval = sctp_make_abort(asoc, chunk, payload_len);
1081        if (!retval)
1082                goto nodata;
1083
1084        sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION,
1085                        sizeof(error) + sizeof(sctp_paramhdr_t));
1086        sctp_addto_chunk(retval, sizeof(error), error);
1087        sctp_addto_param(retval, sizeof(sctp_paramhdr_t), param);
1088
1089nodata:
1090        return retval;
1091}
1092
1093/* Make a HEARTBEAT chunk.  */
1094struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
1095                                  const struct sctp_transport *transport)
1096{
1097        struct sctp_chunk *retval;
1098        sctp_sender_hb_info_t hbinfo;
1099
1100        retval = sctp_make_chunk(asoc, SCTP_CID_HEARTBEAT, 0, sizeof(hbinfo));
1101
1102        if (!retval)
1103                goto nodata;
1104
1105        hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO;
1106        hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t));
1107        hbinfo.daddr = transport->ipaddr;
1108        hbinfo.sent_at = jiffies;
1109        hbinfo.hb_nonce = transport->hb_nonce;
1110
1111        /* Cast away the 'const', as this is just telling the chunk
1112         * what transport it belongs to.
1113         */
1114        retval->transport = (struct sctp_transport *) transport;
1115        retval->subh.hbs_hdr = sctp_addto_chunk(retval, sizeof(hbinfo),
1116                                                &hbinfo);
1117
1118nodata:
1119        return retval;
1120}
1121
1122struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc,
1123                                      const struct sctp_chunk *chunk,
1124                                      const void *payload, const size_t paylen)
1125{
1126        struct sctp_chunk *retval;
1127
1128        retval  = sctp_make_chunk(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen);
1129        if (!retval)
1130                goto nodata;
1131
1132        retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);
1133
1134        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
1135         *
1136         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1137         * HEARTBEAT ACK, * etc.) to the same destination transport
1138         * address from which it * received the DATA or control chunk
1139         * to which it is replying.
1140         *
1141         * [HBACK back to where the HEARTBEAT came from.]
1142         */
1143        if (chunk)
1144                retval->transport = chunk->transport;
1145
1146nodata:
1147        return retval;
1148}
1149
1150/* Create an Operation Error chunk with the specified space reserved.
1151 * This routine can be used for containing multiple causes in the chunk.
1152 */
1153static struct sctp_chunk *sctp_make_op_error_space(
1154        const struct sctp_association *asoc,
1155        const struct sctp_chunk *chunk,
1156        size_t size)
1157{
1158        struct sctp_chunk *retval;
1159
1160        retval = sctp_make_chunk(asoc, SCTP_CID_ERROR, 0,
1161                                 sizeof(sctp_errhdr_t) + size);
1162        if (!retval)
1163                goto nodata;
1164
1165        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
1166         *
1167         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1168         * HEARTBEAT ACK, etc.) to the same destination transport
1169         * address from which it received the DATA or control chunk
1170         * to which it is replying.
1171         *
1172         */
1173        if (chunk)
1174                retval->transport = chunk->transport;
1175
1176nodata:
1177        return retval;
1178}
1179
1180/* Create an Operation Error chunk of a fixed size,
1181 * specifically, max(asoc->pathmtu, SCTP_DEFAULT_MAXSEGMENT)
1182 * This is a helper function to allocate an error chunk for
1183 * for those invalid parameter codes in which we may not want
1184 * to report all the errors, if the incomming chunk is large
1185 */
1186static inline struct sctp_chunk *sctp_make_op_error_fixed(
1187        const struct sctp_association *asoc,
1188        const struct sctp_chunk *chunk)
1189{
1190        size_t size = asoc ? asoc->pathmtu : 0;
1191
1192        if (!size)
1193                size = SCTP_DEFAULT_MAXSEGMENT;
1194
1195        return sctp_make_op_error_space(asoc, chunk, size);
1196}
1197
1198/* Create an Operation Error chunk.  */
1199struct sctp_chunk *sctp_make_op_error(const struct sctp_association *asoc,
1200                                 const struct sctp_chunk *chunk,
1201                                 __be16 cause_code, const void *payload,
1202                                 size_t paylen, size_t reserve_tail)
1203{
1204        struct sctp_chunk *retval;
1205
1206        retval = sctp_make_op_error_space(asoc, chunk, paylen + reserve_tail);
1207        if (!retval)
1208                goto nodata;
1209
1210        sctp_init_cause(retval, cause_code, paylen + reserve_tail);
1211        sctp_addto_chunk(retval, paylen, payload);
1212        if (reserve_tail)
1213                sctp_addto_param(retval, reserve_tail, NULL);
1214
1215nodata:
1216        return retval;
1217}
1218
1219struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc)
1220{
1221        struct sctp_chunk *retval;
1222        struct sctp_hmac *hmac_desc;
1223        struct sctp_authhdr auth_hdr;
1224        __u8 *hmac;
1225
1226        /* Get the first hmac that the peer told us to use */
1227        hmac_desc = sctp_auth_asoc_get_hmac(asoc);
1228        if (unlikely(!hmac_desc))
1229                return NULL;
1230
1231        retval = sctp_make_chunk(asoc, SCTP_CID_AUTH, 0,
1232                        hmac_desc->hmac_len + sizeof(sctp_authhdr_t));
1233        if (!retval)
1234                return NULL;
1235
1236        auth_hdr.hmac_id = htons(hmac_desc->hmac_id);
1237        auth_hdr.shkey_id = htons(asoc->active_key_id);
1238
1239        retval->subh.auth_hdr = sctp_addto_chunk(retval, sizeof(sctp_authhdr_t),
1240                                                &auth_hdr);
1241
1242        hmac = skb_put(retval->skb, hmac_desc->hmac_len);
1243        memset(hmac, 0, hmac_desc->hmac_len);
1244
1245        /* Adjust the chunk header to include the empty MAC */
1246        retval->chunk_hdr->length =
1247                htons(ntohs(retval->chunk_hdr->length) + hmac_desc->hmac_len);
1248        retval->chunk_end = skb_tail_pointer(retval->skb);
1249
1250        return retval;
1251}
1252
1253
1254/********************************************************************
1255 * 2nd Level Abstractions
1256 ********************************************************************/
1257
1258/* Turn an skb into a chunk.
1259 * FIXME: Eventually move the structure directly inside the skb->cb[].
1260 */
1261struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
1262                            const struct sctp_association *asoc,
1263                            struct sock *sk)
1264{
1265        struct sctp_chunk *retval;
1266
1267        retval = kmem_cache_zalloc(sctp_chunk_cachep, GFP_ATOMIC);
1268
1269        if (!retval)
1270                goto nodata;
1271
1272        if (!sk) {
1273                SCTP_DEBUG_PRINTK("chunkifying skb %p w/o an sk\n", skb);
1274        }
1275
1276        INIT_LIST_HEAD(&retval->list);
1277        retval->skb             = skb;
1278        retval->asoc            = (struct sctp_association *)asoc;
1279        retval->has_tsn         = 0;
1280        retval->has_ssn         = 0;
1281        retval->rtt_in_progress = 0;
1282        retval->sent_at         = 0;
1283        retval->singleton       = 1;
1284        retval->end_of_packet   = 0;
1285        retval->ecn_ce_done     = 0;
1286        retval->pdiscard        = 0;
1287
1288        /* sctpimpguide-05.txt Section 2.8.2
1289         * M1) Each time a new DATA chunk is transmitted
1290         * set the 'TSN.Missing.Report' count for that TSN to 0. The
1291         * 'TSN.Missing.Report' count will be used to determine missing chunks
1292         * and when to fast retransmit.
1293         */
1294        retval->tsn_missing_report = 0;
1295        retval->tsn_gap_acked = 0;
1296        retval->fast_retransmit = SCTP_CAN_FRTX;
1297
1298        /* If this is a fragmented message, track all fragments
1299         * of the message (for SEND_FAILED).
1300         */
1301        retval->msg = NULL;
1302
1303        /* Polish the bead hole.  */
1304        INIT_LIST_HEAD(&retval->transmitted_list);
1305        INIT_LIST_HEAD(&retval->frag_list);
1306        SCTP_DBG_OBJCNT_INC(chunk);
1307        atomic_set(&retval->refcnt, 1);
1308
1309nodata:
1310        return retval;
1311}
1312
1313/* Set chunk->source and dest based on the IP header in chunk->skb.  */
1314void sctp_init_addrs(struct sctp_chunk *chunk, union sctp_addr *src,
1315                     union sctp_addr *dest)
1316{
1317        memcpy(&chunk->source, src, sizeof(union sctp_addr));
1318        memcpy(&chunk->dest, dest, sizeof(union sctp_addr));
1319}
1320
1321/* Extract the source address from a chunk.  */
1322const union sctp_addr *sctp_source(const struct sctp_chunk *chunk)
1323{
1324        /* If we have a known transport, use that.  */
1325        if (chunk->transport) {
1326                return &chunk->transport->ipaddr;
1327        } else {
1328                /* Otherwise, extract it from the IP header.  */
1329                return &chunk->source;
1330        }
1331}
1332
1333/* Create a new chunk, setting the type and flags headers from the
1334 * arguments, reserving enough space for a 'paylen' byte payload.
1335 */
1336SCTP_STATIC
1337struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc,
1338                                   __u8 type, __u8 flags, int paylen)
1339{
1340        struct sctp_chunk *retval;
1341        sctp_chunkhdr_t *chunk_hdr;
1342        struct sk_buff *skb;
1343        struct sock *sk;
1344
1345        /* No need to allocate LL here, as this is only a chunk. */
1346        skb = alloc_skb(WORD_ROUND(sizeof(sctp_chunkhdr_t) + paylen),
1347                        GFP_ATOMIC);
1348        if (!skb)
1349                goto nodata;
1350
1351        /* Make room for the chunk header.  */
1352        chunk_hdr = (sctp_chunkhdr_t *)skb_put(skb, sizeof(sctp_chunkhdr_t));
1353        chunk_hdr->type   = type;
1354        chunk_hdr->flags  = flags;
1355        chunk_hdr->length = htons(sizeof(sctp_chunkhdr_t));
1356
1357        sk = asoc ? asoc->base.sk : NULL;
1358        retval = sctp_chunkify(skb, asoc, sk);
1359        if (!retval) {
1360                kfree_skb(skb);
1361                goto nodata;
1362        }
1363
1364        retval->chunk_hdr = chunk_hdr;
1365        retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(struct sctp_chunkhdr);
1366
1367        /* Determine if the chunk needs to be authenticated */
1368        if (sctp_auth_send_cid(type, asoc))
1369                retval->auth = 1;
1370
1371        /* Set the skb to the belonging sock for accounting.  */
1372        skb->sk = sk;
1373
1374        return retval;
1375nodata:
1376        return NULL;
1377}
1378
1379
1380/* Release the memory occupied by a chunk.  */
1381static void sctp_chunk_destroy(struct sctp_chunk *chunk)
1382{
1383        BUG_ON(!list_empty(&chunk->list));
1384        list_del_init(&chunk->transmitted_list);
1385
1386        /* Free the chunk skb data and the SCTP_chunk stub itself. */
1387        dev_kfree_skb(chunk->skb);
1388
1389        SCTP_DBG_OBJCNT_DEC(chunk);
1390        kmem_cache_free(sctp_chunk_cachep, chunk);
1391}
1392
1393/* Possibly, free the chunk.  */
1394void sctp_chunk_free(struct sctp_chunk *chunk)
1395{
1396        /* Release our reference on the message tracker. */
1397        if (chunk->msg)
1398                sctp_datamsg_put(chunk->msg);
1399
1400        sctp_chunk_put(chunk);
1401}
1402
1403/* Grab a reference to the chunk. */
1404void sctp_chunk_hold(struct sctp_chunk *ch)
1405{
1406        atomic_inc(&ch->refcnt);
1407}
1408
1409/* Release a reference to the chunk. */
1410void sctp_chunk_put(struct sctp_chunk *ch)
1411{
1412        if (atomic_dec_and_test(&ch->refcnt))
1413                sctp_chunk_destroy(ch);
1414}
1415
1416/* Append bytes to the end of a chunk.  Will panic if chunk is not big
1417 * enough.
1418 */
1419void *sctp_addto_chunk(struct sctp_chunk *chunk, int len, const void *data)
1420{
1421        void *target;
1422        void *padding;
1423        int chunklen = ntohs(chunk->chunk_hdr->length);
1424        int padlen = WORD_ROUND(chunklen) - chunklen;
1425
1426        padding = skb_put(chunk->skb, padlen);
1427        target = skb_put(chunk->skb, len);
1428
1429        memset(padding, 0, padlen);
1430        memcpy(target, data, len);
1431
1432        /* Adjust the chunk length field.  */
1433        chunk->chunk_hdr->length = htons(chunklen + padlen + len);
1434        chunk->chunk_end = skb_tail_pointer(chunk->skb);
1435
1436        return target;
1437}
1438
1439/* Append bytes to the end of a chunk. Returns NULL if there isn't sufficient
1440 * space in the chunk
1441 */
1442void *sctp_addto_chunk_fixed(struct sctp_chunk *chunk,
1443                             int len, const void *data)
1444{
1445        if (skb_tailroom(chunk->skb) >= len)
1446                return sctp_addto_chunk(chunk, len, data);
1447        else
1448                return NULL;
1449}
1450
1451/* Append bytes from user space to the end of a chunk.  Will panic if
1452 * chunk is not big enough.
1453 * Returns a kernel err value.
1454 */
1455int sctp_user_addto_chunk(struct sctp_chunk *chunk, int off, int len,
1456                          struct iovec *data)
1457{
1458        __u8 *target;
1459        int err = 0;
1460
1461        /* Make room in chunk for data.  */
1462        target = skb_put(chunk->skb, len);
1463
1464        /* Copy data (whole iovec) into chunk */
1465        if ((err = memcpy_fromiovecend(target, data, off, len)))
1466                goto out;
1467
1468        /* Adjust the chunk length field.  */
1469        chunk->chunk_hdr->length =
1470                htons(ntohs(chunk->chunk_hdr->length) + len);
1471        chunk->chunk_end = skb_tail_pointer(chunk->skb);
1472
1473out:
1474        return err;
1475}
1476
1477/* Helper function to assign a TSN if needed.  This assumes that both
1478 * the data_hdr and association have already been assigned.
1479 */
1480void sctp_chunk_assign_ssn(struct sctp_chunk *chunk)
1481{
1482        struct sctp_datamsg *msg;
1483        struct sctp_chunk *lchunk;
1484        struct sctp_stream *stream;
1485        __u16 ssn;
1486        __u16 sid;
1487
1488        if (chunk->has_ssn)
1489                return;
1490
1491        /* All fragments will be on the same stream */
1492        sid = ntohs(chunk->subh.data_hdr->stream);
1493        stream = &chunk->asoc->ssnmap->out;
1494
1495        /* Now assign the sequence number to the entire message.
1496         * All fragments must have the same stream sequence number.
1497         */
1498        msg = chunk->msg;
1499        list_for_each_entry(lchunk, &msg->chunks, frag_list) {
1500                if (lchunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
1501                        ssn = 0;
1502                } else {
1503                        if (lchunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG)
1504                                ssn = sctp_ssn_next(stream, sid);
1505                        else
1506                                ssn = sctp_ssn_peek(stream, sid);
1507                }
1508
1509                lchunk->subh.data_hdr->ssn = htons(ssn);
1510                lchunk->has_ssn = 1;
1511        }
1512}
1513
1514/* Helper function to assign a TSN if needed.  This assumes that both
1515 * the data_hdr and association have already been assigned.
1516 */
1517void sctp_chunk_assign_tsn(struct sctp_chunk *chunk)
1518{
1519        if (!chunk->has_tsn) {
1520                /* This is the last possible instant to
1521                 * assign a TSN.
1522                 */
1523                chunk->subh.data_hdr->tsn =
1524                        htonl(sctp_association_get_next_tsn(chunk->asoc));
1525                chunk->has_tsn = 1;
1526        }
1527}
1528
1529/* Create a CLOSED association to use with an incoming packet.  */
1530struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *ep,
1531                                        struct sctp_chunk *chunk,
1532                                        gfp_t gfp)
1533{
1534        struct sctp_association *asoc;
1535        struct sk_buff *skb;
1536        sctp_scope_t scope;
1537        struct sctp_af *af;
1538
1539        /* Create the bare association.  */
1540        scope = sctp_scope(sctp_source(chunk));
1541        asoc = sctp_association_new(ep, ep->base.sk, scope, gfp);
1542        if (!asoc)
1543                goto nodata;
1544        asoc->temp = 1;
1545        skb = chunk->skb;
1546        /* Create an entry for the source address of the packet.  */
1547        af = sctp_get_af_specific(ipver2af(ip_hdr(skb)->version));
1548        if (unlikely(!af))
1549                goto fail;
1550        af->from_skb(&asoc->c.peer_addr, skb, 1);
1551nodata:
1552        return asoc;
1553
1554fail:
1555        sctp_association_free(asoc);
1556        return NULL;
1557}
1558
1559/* Build a cookie representing asoc.
1560 * This INCLUDES the param header needed to put the cookie in the INIT ACK.
1561 */
1562static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
1563                                      const struct sctp_association *asoc,
1564                                      const struct sctp_chunk *init_chunk,
1565                                      int *cookie_len,
1566                                      const __u8 *raw_addrs, int addrs_len)
1567{
1568        sctp_cookie_param_t *retval;
1569        struct sctp_signed_cookie *cookie;
1570        struct scatterlist sg;
1571        int headersize, bodysize;
1572        unsigned int keylen;
1573        char *key;
1574
1575        /* Header size is static data prior to the actual cookie, including
1576         * any padding.
1577         */
1578        headersize = sizeof(sctp_paramhdr_t) +
1579                     (sizeof(struct sctp_signed_cookie) -
1580                      sizeof(struct sctp_cookie));
1581        bodysize = sizeof(struct sctp_cookie)
1582                + ntohs(init_chunk->chunk_hdr->length) + addrs_len;
1583
1584        /* Pad out the cookie to a multiple to make the signature
1585         * functions simpler to write.
1586         */
1587        if (bodysize % SCTP_COOKIE_MULTIPLE)
1588                bodysize += SCTP_COOKIE_MULTIPLE
1589                        - (bodysize % SCTP_COOKIE_MULTIPLE);
1590        *cookie_len = headersize + bodysize;
1591
1592        /* Clear this memory since we are sending this data structure
1593         * out on the network.
1594         */
1595        retval = kzalloc(*cookie_len, GFP_ATOMIC);
1596        if (!retval)
1597                goto nodata;
1598
1599        cookie = (struct sctp_signed_cookie *) retval->body;
1600
1601        /* Set up the parameter header.  */
1602        retval->p.type = SCTP_PARAM_STATE_COOKIE;
1603        retval->p.length = htons(*cookie_len);
1604
1605        /* Copy the cookie part of the association itself.  */
1606        cookie->c = asoc->c;
1607        /* Save the raw address list length in the cookie. */
1608        cookie->c.raw_addr_list_len = addrs_len;
1609
1610        /* Remember PR-SCTP capability. */
1611        cookie->c.prsctp_capable = asoc->peer.prsctp_capable;
1612
1613        /* Save adaptation indication in the cookie. */
1614        cookie->c.adaptation_ind = asoc->peer.adaptation_ind;
1615
1616        /* Set an expiration time for the cookie.  */
1617        do_gettimeofday(&cookie->c.expiration);
1618        TIMEVAL_ADD(asoc->cookie_life, cookie->c.expiration);
1619
1620        /* Copy the peer's init packet.  */
1621        memcpy(&cookie->c.peer_init[0], init_chunk->chunk_hdr,
1622               ntohs(init_chunk->chunk_hdr->length));
1623
1624        /* Copy the raw local address list of the association. */
1625        memcpy((__u8 *)&cookie->c.peer_init[0] +
1626               ntohs(init_chunk->chunk_hdr->length), raw_addrs, addrs_len);
1627
1628        if (sctp_sk(ep->base.sk)->hmac) {
1629                struct hash_desc desc;
1630
1631                /* Sign the message.  */
1632                sg_init_one(&sg, &cookie->c, bodysize);
1633                keylen = SCTP_SECRET_SIZE;
1634                key = (char *)ep->secret_key[ep->current_key];
1635                desc.tfm = sctp_sk(ep->base.sk)->hmac;
1636                desc.flags = 0;
1637
1638                if (crypto_hash_setkey(desc.tfm, key, keylen) ||
1639                    crypto_hash_digest(&desc, &sg, bodysize, cookie->signature))
1640                        goto free_cookie;
1641        }
1642
1643        return retval;
1644
1645free_cookie:
1646        kfree(retval);
1647nodata:
1648        *cookie_len = 0;
1649        return NULL;
1650}
1651
1652/* Unpack the cookie from COOKIE ECHO chunk, recreating the association.  */
1653struct sctp_association *sctp_unpack_cookie(
1654        const struct sctp_endpoint *ep,
1655        const struct sctp_association *asoc,
1656        struct sctp_chunk *chunk, gfp_t gfp,
1657        int *error, struct sctp_chunk **errp)
1658{
1659        struct sctp_association *retval = NULL;
1660        struct sctp_signed_cookie *cookie;
1661        struct sctp_cookie *bear_cookie;
1662        int headersize, bodysize, fixed_size;
1663        __u8 *digest = ep->digest;
1664        struct scatterlist sg;
1665        unsigned int keylen, len;
1666        char *key;
1667        sctp_scope_t scope;
1668        struct sk_buff *skb = chunk->skb;
1669        struct timeval tv;
1670        struct hash_desc desc;
1671
1672        /* Header size is static data prior to the actual cookie, including
1673         * any padding.
1674         */
1675        headersize = sizeof(sctp_chunkhdr_t) +
1676                     (sizeof(struct sctp_signed_cookie) -
1677                      sizeof(struct sctp_cookie));
1678        bodysize = ntohs(chunk->chunk_hdr->length) - headersize;
1679        fixed_size = headersize + sizeof(struct sctp_cookie);
1680
1681        /* Verify that the chunk looks like it even has a cookie.
1682         * There must be enough room for our cookie and our peer's
1683         * INIT chunk.
1684         */
1685        len = ntohs(chunk->chunk_hdr->length);
1686        if (len < fixed_size + sizeof(struct sctp_chunkhdr))
1687                goto malformed;
1688
1689        /* Verify that the cookie has been padded out. */
1690        if (bodysize % SCTP_COOKIE_MULTIPLE)
1691                goto malformed;
1692
1693        /* Process the cookie.  */
1694        cookie = chunk->subh.cookie_hdr;
1695        bear_cookie = &cookie->c;
1696
1697        if (!sctp_sk(ep->base.sk)->hmac)
1698                goto no_hmac;
1699
1700        /* Check the signature.  */
1701        keylen = SCTP_SECRET_SIZE;
1702        sg_init_one(&sg, bear_cookie, bodysize);
1703        key = (char *)ep->secret_key[ep->current_key];
1704        desc.tfm = sctp_sk(ep->base.sk)->hmac;
1705        desc.flags = 0;
1706
1707        memset(digest, 0x00, SCTP_SIGNATURE_SIZE);
1708        if (crypto_hash_setkey(desc.tfm, key, keylen) ||
1709            crypto_hash_digest(&desc, &sg, bodysize, digest)) {
1710                *error = -SCTP_IERROR_NOMEM;
1711                goto fail;
1712        }
1713
1714        if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
1715                /* Try the previous key. */
1716                key = (char *)ep->secret_key[ep->last_key];
1717                memset(digest, 0x00, SCTP_SIGNATURE_SIZE);
1718                if (crypto_hash_setkey(desc.tfm, key, keylen) ||
1719                    crypto_hash_digest(&desc, &sg, bodysize, digest)) {
1720                        *error = -SCTP_IERROR_NOMEM;
1721                        goto fail;
1722                }
1723
1724                if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
1725                        /* Yikes!  Still bad signature! */
1726                        *error = -SCTP_IERROR_BAD_SIG;
1727                        goto fail;
1728                }
1729        }
1730
1731no_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                skb_get_timestamp(skb, &tv);
1760        else
1761                do_gettimeofday(&tv);
1762
1763        if (!asoc && tv_lt(bear_cookie->expiration, tv)) {
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 = (tv.tv_sec -
1776                                bear_cookie->expiration.tv_sec) * 1000000L +
1777                                tv.tv_usec - bear_cookie->expiration.tv_usec;
1778                        __be32 n = htonl(usecs);
1779
1780                        sctp_init_cause(*errp, SCTP_ERROR_STALE_COOKIE,
1781                                        sizeof(n));
1782                        sctp_addto_chunk(*errp, sizeof(n), &n);
1783                        *error = -SCTP_IERROR_STALE_COOKIE;
1784                } else
1785                        *error = -SCTP_IERROR_NOMEM;
1786
1787                goto fail;
1788        }
1789
1790        /* Make a new base association.  */
1791        scope = sctp_scope(sctp_source(chunk));
1792        retval = sctp_association_new(ep, ep->base.sk, scope, gfp);
1793        if (!retval) {
1794                *error = -SCTP_IERROR_NOMEM;
1795                goto fail;
1796        }
1797
1798        /* Set up our peer's port number.  */
1799        retval->peer.port = ntohs(chunk->sctp_hdr->source);
1800
1801        /* Populate the association from the cookie.  */
1802        memcpy(&retval->c, bear_cookie, sizeof(*bear_cookie));
1803
1804        if (sctp_assoc_set_bind_addr_from_cookie(retval, bear_cookie,
1805                                                 GFP_ATOMIC) < 0) {
1806                *error = -SCTP_IERROR_NOMEM;
1807                goto fail;
1808        }
1809
1810        /* Also, add the destination address. */
1811        if (list_empty(&retval->base.bind_addr.address_list)) {
1812                sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest,
1813                                SCTP_ADDR_SRC, GFP_ATOMIC);
1814        }
1815
1816        retval->next_tsn = retval->c.initial_tsn;
1817        retval->ctsn_ack_point = retval->next_tsn - 1;
1818        retval->addip_serial = retval->c.initial_tsn;
1819        retval->adv_peer_ack_point = retval->ctsn_ack_point;
1820        retval->peer.prsctp_capable = retval->c.prsctp_capable;
1821        retval->peer.adaptation_ind = retval->c.adaptation_ind;
1822
1823        /* The INIT stuff will be done by the side effects.  */
1824        return retval;
1825
1826fail:
1827        if (retval)
1828                sctp_association_free(retval);
1829
1830        return NULL;
1831
1832malformed:
1833        /* Yikes!  The packet is either corrupt or deliberately
1834         * malformed.
1835         */
1836        *error = -SCTP_IERROR_MALFORMED;
1837        goto fail;
1838}
1839
1840/********************************************************************
1841 * 3rd Level Abstractions
1842 ********************************************************************/
1843
1844struct __sctp_missing {
1845        __be32 num_missing;
1846        __be16 type;
1847}  __packed;
1848
1849/*
1850 * Report a missing mandatory parameter.
1851 */
1852static int sctp_process_missing_param(const struct sctp_association *asoc,
1853                                      sctp_param_t paramtype,
1854                                      struct sctp_chunk *chunk,
1855                                      struct sctp_chunk **errp)
1856{
1857        struct __sctp_missing report;
1858        __u16 len;
1859
1860        len = WORD_ROUND(sizeof(report));
1861
1862        /* Make an ERROR chunk, preparing enough room for
1863         * returning multiple unknown parameters.
1864         */
1865        if (!*errp)
1866                *errp = sctp_make_op_error_space(asoc, chunk, len);
1867
1868        if (*errp) {
1869                report.num_missing = htonl(1);
1870                report.type = paramtype;
1871                sctp_init_cause(*errp, SCTP_ERROR_MISS_PARAM,
1872                                sizeof(report));
1873                sctp_addto_chunk(*errp, sizeof(report), &report);
1874        }
1875
1876        /* Stop processing this chunk. */
1877        return 0;
1878}
1879
1880/* Report an Invalid Mandatory Parameter.  */
1881static int sctp_process_inv_mandatory(const struct sctp_association *asoc,
1882                                      struct sctp_chunk *chunk,
1883                                      struct sctp_chunk **errp)
1884{
1885        /* Invalid Mandatory Parameter Error has no payload. */
1886
1887        if (!*errp)
1888                *errp = sctp_make_op_error_space(asoc, chunk, 0);
1889
1890        if (*errp)
1891                sctp_init_cause(*errp, SCTP_ERROR_INV_PARAM, 0);
1892
1893        /* Stop processing this chunk. */
1894        return 0;
1895}
1896
1897static int sctp_process_inv_paramlength(const struct sctp_association *asoc,
1898                                        struct sctp_paramhdr *param,
1899                                        const struct sctp_chunk *chunk,
1900                                        struct sctp_chunk **errp)
1901{
1902        /* This is a fatal error.  Any accumulated non-fatal errors are
1903         * not reported.
1904         */
1905        if (*errp)
1906                sctp_chunk_free(*errp);
1907
1908        /* Create an error chunk and fill it in with our payload. */
1909        *errp = sctp_make_violation_paramlen(asoc, chunk, param);
1910
1911        return 0;
1912}
1913
1914
1915/* Do not attempt to handle the HOST_NAME parm.  However, do
1916 * send back an indicator to the peer.
1917 */
1918static int sctp_process_hn_param(const struct sctp_association *asoc,
1919                                 union sctp_params param,
1920                                 struct sctp_chunk *chunk,
1921                                 struct sctp_chunk **errp)
1922{
1923        __u16 len = ntohs(param.p->length);
1924
1925        /* Processing of the HOST_NAME parameter will generate an
1926         * ABORT.  If we've accumulated any non-fatal errors, they
1927         * would be unrecognized parameters and we should not include
1928         * them in the ABORT.
1929         */
1930        if (*errp)
1931                sctp_chunk_free(*errp);
1932
1933        *errp = sctp_make_op_error_space(asoc, chunk, len);
1934
1935        if (*errp) {
1936                sctp_init_cause(*errp, SCTP_ERROR_DNS_FAILED, len);
1937                sctp_addto_chunk(*errp, len, param.v);
1938        }
1939
1940        /* Stop processing this chunk. */
1941        return 0;
1942}
1943
1944static int sctp_verify_ext_param(struct net *net, union sctp_params param)
1945{
1946        __u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
1947        int have_auth = 0;
1948        int have_asconf = 0;
1949        int i;
1950
1951        for (i = 0; i < num_ext; i++) {
1952                switch (param.ext->chunks[i]) {
1953                    case SCTP_CID_AUTH:
1954                            have_auth = 1;
1955                            break;
1956                    case SCTP_CID_ASCONF:
1957                    case SCTP_CID_ASCONF_ACK:
1958                            have_asconf = 1;
1959                            break;
1960                }
1961        }
1962
1963        /* ADD-IP Security: The draft requires us to ABORT or ignore the
1964         * INIT/INIT-ACK if ADD-IP is listed, but AUTH is not.  Do this
1965         * only if ADD-IP is turned on and we are not backward-compatible
1966         * mode.
1967         */
1968        if (net->sctp.addip_noauth)
1969                return 1;
1970
1971        if (net->sctp.addip_enable && !have_auth && have_asconf)
1972                return 0;
1973
1974        return 1;
1975}
1976
1977static void sctp_process_ext_param(struct sctp_association *asoc,
1978                                    union sctp_params param)
1979{
1980        struct net *net = sock_net(asoc->base.sk);
1981        __u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
1982        int i;
1983
1984        for (i = 0; i < num_ext; i++) {
1985                switch (param.ext->chunks[i]) {
1986                    case SCTP_CID_FWD_TSN:
1987                            if (net->sctp.prsctp_enable &&
1988                                !asoc->peer.prsctp_capable)
1989                                    asoc->peer.prsctp_capable = 1;
1990                            break;
1991                    case SCTP_CID_AUTH:
1992                            /* if the peer reports AUTH, assume that he
1993                             * supports AUTH.
1994                             */
1995                            if (net->sctp.auth_enable)
1996                                    asoc->peer.auth_capable = 1;
1997                            break;
1998                    case SCTP_CID_ASCONF:
1999                    case SCTP_CID_ASCONF_ACK:
2000                            if (net->sctp.addip_enable)
2001                                    asoc->peer.asconf_capable = 1;
2002                            break;
2003                    default:
2004                            break;
2005                }
2006        }
2007}
2008
2009/* RFC 3.2.1 & the Implementers Guide 2.2.
2010 *
2011 * The Parameter Types are encoded such that the
2012 * highest-order two bits specify the action that must be
2013 * taken if the processing endpoint does not recognize the
2014 * Parameter Type.
2015 *
2016 * 00 - Stop processing this parameter; do not process any further
2017 *      parameters within this chunk
2018 *
2019 * 01 - Stop processing this parameter, do not process any further
2020 *      parameters within this chunk, and report the unrecognized
2021 *      parameter in an 'Unrecognized Parameter' ERROR chunk.
2022 *
2023 * 10 - Skip this parameter and continue processing.
2024 *
2025 * 11 - Skip this parameter and continue processing but
2026 *      report the unrecognized parameter in an
2027 *      'Unrecognized Parameter' ERROR chunk.
2028 *
2029 * Return value:
2030 *      SCTP_IERROR_NO_ERROR - continue with the chunk
2031 *      SCTP_IERROR_ERROR    - stop and report an error.
2032 *      SCTP_IERROR_NOMEME   - out of memory.
2033 */
2034static sctp_ierror_t sctp_process_unk_param(const struct sctp_association *asoc,
2035                                            union sctp_params param,
2036                                            struct sctp_chunk *chunk,
2037                                            struct sctp_chunk **errp)
2038{
2039        int retval = SCTP_IERROR_NO_ERROR;
2040
2041        switch (param.p->type & SCTP_PARAM_ACTION_MASK) {
2042        case SCTP_PARAM_ACTION_DISCARD:
2043                retval =  SCTP_IERROR_ERROR;
2044                break;
2045        case SCTP_PARAM_ACTION_SKIP:
2046                break;
2047        case SCTP_PARAM_ACTION_DISCARD_ERR:
2048                retval =  SCTP_IERROR_ERROR;
2049                /* Fall through */
2050        case SCTP_PARAM_ACTION_SKIP_ERR:
2051                /* Make an ERROR chunk, preparing enough room for
2052                 * returning multiple unknown parameters.
2053                 */
2054                if (NULL == *errp)
2055                        *errp = sctp_make_op_error_fixed(asoc, chunk);
2056
2057                if (*errp) {
2058                        if (!sctp_init_cause_fixed(*errp, SCTP_ERROR_UNKNOWN_PARAM,
2059                                        WORD_ROUND(ntohs(param.p->length))))
2060                                sctp_addto_chunk_fixed(*errp,
2061                                                WORD_ROUND(ntohs(param.p->length)),
2062                                                param.v);
2063                } else {
2064                        /* If there is no memory for generating the ERROR
2065                         * report as specified, an ABORT will be triggered
2066                         * to the peer and the association won't be
2067                         * established.
2068                         */
2069                        retval = SCTP_IERROR_NOMEM;
2070                }
2071                break;
2072        default:
2073                break;
2074        }
2075
2076        return retval;
2077}
2078
2079/* Verify variable length parameters
2080 * Return values:
2081 *      SCTP_IERROR_ABORT - trigger an ABORT
2082 *      SCTP_IERROR_NOMEM - out of memory (abort)
2083 *      SCTP_IERROR_ERROR - stop processing, trigger an ERROR
2084 *      SCTP_IERROR_NO_ERROR - continue with the chunk
2085 */
2086static sctp_ierror_t sctp_verify_param(struct net *net,
2087                                        const struct sctp_association *asoc,
2088                                        union sctp_params param,
2089                                        sctp_cid_t cid,
2090                                        struct sctp_chunk *chunk,
2091                                        struct sctp_chunk **err_chunk)
2092{
2093        struct sctp_hmac_algo_param *hmacs;
2094        int retval = SCTP_IERROR_NO_ERROR;
2095        __u16 n_elt, id = 0;
2096        int i;
2097
2098        /* FIXME - This routine is not looking at each parameter per the
2099         * chunk type, i.e., unrecognized parameters should be further
2100         * identified based on the chunk id.
2101         */
2102
2103        switch (param.p->type) {
2104        case SCTP_PARAM_IPV4_ADDRESS:
2105        case SCTP_PARAM_IPV6_ADDRESS:
2106        case SCTP_PARAM_COOKIE_PRESERVATIVE:
2107        case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2108        case SCTP_PARAM_STATE_COOKIE:
2109        case SCTP_PARAM_HEARTBEAT_INFO:
2110        case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2111        case SCTP_PARAM_ECN_CAPABLE:
2112        case SCTP_PARAM_ADAPTATION_LAYER_IND:
2113                break;
2114
2115        case SCTP_PARAM_SUPPORTED_EXT:
2116                if (!sctp_verify_ext_param(net, param))
2117                        return SCTP_IERROR_ABORT;
2118                break;
2119
2120        case SCTP_PARAM_SET_PRIMARY:
2121                if (net->sctp.addip_enable)
2122                        break;
2123                goto fallthrough;
2124
2125        case SCTP_PARAM_HOST_NAME_ADDRESS:
2126                /* Tell the peer, we won't support this param.  */
2127                sctp_process_hn_param(asoc, param, chunk, err_chunk);
2128                retval = SCTP_IERROR_ABORT;
2129                break;
2130
2131        case SCTP_PARAM_FWD_TSN_SUPPORT:
2132                if (net->sctp.prsctp_enable)
2133                        break;
2134                goto fallthrough;
2135
2136        case SCTP_PARAM_RANDOM:
2137                if (!net->sctp.auth_enable)
2138                        goto fallthrough;
2139
2140                /* SCTP-AUTH: Secion 6.1
2141                 * If the random number is not 32 byte long the association
2142                 * MUST be aborted.  The ABORT chunk SHOULD contain the error
2143                 * cause 'Protocol Violation'.
2144                 */
2145                if (SCTP_AUTH_RANDOM_LENGTH !=
2146                        ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) {
2147                        sctp_process_inv_paramlength(asoc, param.p,
2148                                                        chunk, err_chunk);
2149                        retval = SCTP_IERROR_ABORT;
2150                }
2151                break;
2152
2153        case SCTP_PARAM_CHUNKS:
2154                if (!net->sctp.auth_enable)
2155                        goto fallthrough;
2156
2157                /* SCTP-AUTH: Section 3.2
2158                 * The CHUNKS parameter MUST be included once in the INIT or
2159                 *  INIT-ACK chunk if the sender wants to receive authenticated
2160                 *  chunks.  Its maximum length is 260 bytes.
2161                 */
2162                if (260 < ntohs(param.p->length)) {
2163                        sctp_process_inv_paramlength(asoc, param.p,
2164                                                     chunk, err_chunk);
2165                        retval = SCTP_IERROR_ABORT;
2166                }
2167                break;
2168
2169        case SCTP_PARAM_HMAC_ALGO:
2170                if (!net->sctp.auth_enable)
2171                        goto fallthrough;
2172
2173                hmacs = (struct sctp_hmac_algo_param *)param.p;
2174                n_elt = (ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) >> 1;
2175
2176                /* SCTP-AUTH: Section 6.1
2177                 * The HMAC algorithm based on SHA-1 MUST be supported and
2178                 * included in the HMAC-ALGO parameter.
2179                 */
2180                for (i = 0; i < n_elt; i++) {
2181                        id = ntohs(hmacs->hmac_ids[i]);
2182
2183                        if (id == SCTP_AUTH_HMAC_ID_SHA1)
2184                                break;
2185                }
2186
2187                if (id != SCTP_AUTH_HMAC_ID_SHA1) {
2188                        sctp_process_inv_paramlength(asoc, param.p, chunk,
2189                                                     err_chunk);
2190                        retval = SCTP_IERROR_ABORT;
2191                }
2192                break;
2193fallthrough:
2194        default:
2195                SCTP_DEBUG_PRINTK("Unrecognized param: %d for chunk %d.\n",
2196                                ntohs(param.p->type), cid);
2197                retval = sctp_process_unk_param(asoc, param, chunk, err_chunk);
2198                break;
2199        }
2200        return retval;
2201}
2202
2203/* Verify the INIT packet before we process it.  */
2204int sctp_verify_init(struct net *net, const struct sctp_association *asoc,
2205                     sctp_cid_t cid,
2206                     sctp_init_chunk_t *peer_init,
2207                     struct sctp_chunk *chunk,
2208                     struct sctp_chunk **errp)
2209{
2210        union sctp_params param;
2211        int has_cookie = 0;
2212        int result;
2213
2214        /* Verify stream values are non-zero. */
2215        if ((0 == peer_init->init_hdr.num_outbound_streams) ||
2216            (0 == peer_init->init_hdr.num_inbound_streams) ||
2217            (0 == peer_init->init_hdr.init_tag) ||
2218            (SCTP_DEFAULT_MINWINDOW > ntohl(peer_init->init_hdr.a_rwnd))) {
2219
2220                return sctp_process_inv_mandatory(asoc, chunk, errp);
2221        }
2222
2223        /* Check for missing mandatory parameters.  */
2224        sctp_walk_params(param, peer_init, init_hdr.params) {
2225
2226                if (SCTP_PARAM_STATE_COOKIE == param.p->type)
2227                        has_cookie = 1;
2228
2229        } /* for (loop through all parameters) */
2230
2231        /* There is a possibility that a parameter length was bad and
2232         * in that case we would have stoped walking the parameters.
2233         * The current param.p would point at the bad one.
2234         * Current consensus on the mailing list is to generate a PROTOCOL
2235         * VIOLATION error.  We build the ERROR chunk here and let the normal
2236         * error handling code build and send the packet.
2237         */
2238        if (param.v != (void*)chunk->chunk_end)
2239                return sctp_process_inv_paramlength(asoc, param.p, chunk, errp);
2240
2241        /* The only missing mandatory param possible today is
2242         * the state cookie for an INIT-ACK chunk.
2243         */
2244        if ((SCTP_CID_INIT_ACK == cid) && !has_cookie)
2245                return sctp_process_missing_param(asoc, SCTP_PARAM_STATE_COOKIE,
2246                                                  chunk, errp);
2247
2248        /* Verify all the variable length parameters */
2249        sctp_walk_params(param, peer_init, init_hdr.params) {
2250
2251                result = sctp_verify_param(net, asoc, param, cid, chunk, errp);
2252                switch (result) {
2253                    case SCTP_IERROR_ABORT:
2254                    case SCTP_IERROR_NOMEM:
2255                                return 0;
2256                    case SCTP_IERROR_ERROR:
2257                                return 1;
2258                    case SCTP_IERROR_NO_ERROR:
2259                    default:
2260                                break;
2261                }
2262
2263        } /* for (loop through all parameters) */
2264
2265        return 1;
2266}
2267
2268/* Unpack the parameters in an INIT packet into an association.
2269 * Returns 0 on failure, else success.
2270 * FIXME:  This is an association method.
2271 */
2272int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,
2273                      const union sctp_addr *peer_addr,
2274                      sctp_init_chunk_t *peer_init, gfp_t gfp)
2275{
2276        struct net *net = sock_net(asoc->base.sk);
2277        union sctp_params param;
2278        struct sctp_transport *transport;
2279        struct list_head *pos, *temp;
2280        struct sctp_af *af;
2281        union sctp_addr addr;
2282        char *cookie;
2283        int src_match = 0;
2284
2285        /* We must include the address that the INIT packet came from.
2286         * This is the only address that matters for an INIT packet.
2287         * When processing a COOKIE ECHO, we retrieve the from address
2288         * of the INIT from the cookie.
2289         */
2290
2291        /* This implementation defaults to making the first transport
2292         * added as the primary transport.  The source address seems to
2293         * be a a better choice than any of the embedded addresses.
2294         */
2295        if(!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
2296                goto nomem;
2297
2298        if (sctp_cmp_addr_exact(sctp_source(chunk), peer_addr))
2299                src_match = 1;
2300
2301        /* Process the initialization parameters.  */
2302        sctp_walk_params(param, peer_init, init_hdr.params) {
2303                if (!src_match && (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
2304                    param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
2305                        af = sctp_get_af_specific(param_type2af(param.p->type));
2306                        af->from_addr_param(&addr, param.addr,
2307                                            chunk->sctp_hdr->source, 0);
2308                        if (sctp_cmp_addr_exact(sctp_source(chunk), &addr))
2309                                src_match = 1;
2310                }
2311
2312                if (!sctp_process_param(asoc, param, peer_addr, gfp))
2313                        goto clean_up;
2314        }
2315
2316        /* source address of chunk may not match any valid address */
2317        if (!src_match)
2318                goto clean_up;
2319
2320        /* AUTH: After processing the parameters, make sure that we
2321         * have all the required info to potentially do authentications.
2322         */
2323        if (asoc->peer.auth_capable && (!asoc->peer.peer_random ||
2324                                        !asoc->peer.peer_hmacs))
2325                asoc->peer.auth_capable = 0;
2326
2327        /* In a non-backward compatible mode, if the peer claims
2328         * support for ADD-IP but not AUTH,  the ADD-IP spec states
2329         * that we MUST ABORT the association. Section 6.  The section
2330         * also give us an option to silently ignore the packet, which
2331         * is what we'll do here.
2332         */
2333        if (!net->sctp.addip_noauth &&
2334             (asoc->peer.asconf_capable && !asoc->peer.auth_capable)) {
2335                asoc->peer.addip_disabled_mask |= (SCTP_PARAM_ADD_IP |
2336                                                  SCTP_PARAM_DEL_IP |
2337                                                  SCTP_PARAM_SET_PRIMARY);
2338                asoc->peer.asconf_capable = 0;
2339                goto clean_up;
2340        }
2341
2342        /* Walk list of transports, removing transports in the UNKNOWN state. */
2343        list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2344                transport = list_entry(pos, struct sctp_transport, transports);
2345                if (transport->state == SCTP_UNKNOWN) {
2346                        sctp_assoc_rm_peer(asoc, transport);
2347                }
2348        }
2349
2350        /* The fixed INIT headers are always in network byte
2351         * order.
2352         */
2353        asoc->peer.i.init_tag =
2354                ntohl(peer_init->init_hdr.init_tag);
2355        asoc->peer.i.a_rwnd =
2356                ntohl(peer_init->init_hdr.a_rwnd);
2357        asoc->peer.i.num_outbound_streams =
2358                ntohs(peer_init->init_hdr.num_outbound_streams);
2359        asoc->peer.i.num_inbound_streams =
2360                ntohs(peer_init->init_hdr.num_inbound_streams);
2361        asoc->peer.i.initial_tsn =
2362                ntohl(peer_init->init_hdr.initial_tsn);
2363
2364        /* Apply the upper bounds for output streams based on peer's
2365         * number of inbound streams.
2366         */
2367        if (asoc->c.sinit_num_ostreams  >
2368            ntohs(peer_init->init_hdr.num_inbound_streams)) {
2369                asoc->c.sinit_num_ostreams =
2370                        ntohs(peer_init->init_hdr.num_inbound_streams);
2371        }
2372
2373        if (asoc->c.sinit_max_instreams >
2374            ntohs(peer_init->init_hdr.num_outbound_streams)) {
2375                asoc->c.sinit_max_instreams =
2376                        ntohs(peer_init->init_hdr.num_outbound_streams);
2377        }
2378
2379        /* Copy Initiation tag from INIT to VT_peer in cookie.   */
2380        asoc->c.peer_vtag = asoc->peer.i.init_tag;
2381
2382        /* Peer Rwnd   : Current calculated value of the peer's rwnd.  */
2383        asoc->peer.rwnd = asoc->peer.i.a_rwnd;
2384
2385        /* Copy cookie in case we need to resend COOKIE-ECHO. */
2386        cookie = asoc->peer.cookie;
2387        if (cookie) {
2388                asoc->peer.cookie = kmemdup(cookie, asoc->peer.cookie_len, gfp);
2389                if (!asoc->peer.cookie)
2390                        goto clean_up;
2391        }
2392
2393        /* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily
2394         * high (for example, implementations MAY use the size of the receiver
2395         * advertised window).
2396         */
2397        list_for_each_entry(transport, &asoc->peer.transport_addr_list,
2398                        transports) {
2399                transport->ssthresh = asoc->peer.i.a_rwnd;
2400        }
2401
2402        /* Set up the TSN tracking pieces.  */
2403        if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
2404                                asoc->peer.i.initial_tsn, gfp))
2405                goto clean_up;
2406
2407        /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
2408         *
2409         * The stream sequence number in all the streams shall start
2410         * from 0 when the association is established.  Also, when the
2411         * stream sequence number reaches the value 65535 the next
2412         * stream sequence number shall be set to 0.
2413         */
2414
2415        /* Allocate storage for the negotiated streams if it is not a temporary
2416         * association.
2417         */
2418        if (!asoc->temp) {
2419                int error;
2420
2421                asoc->ssnmap = sctp_ssnmap_new(asoc->c.sinit_max_instreams,
2422                                               asoc->c.sinit_num_ostreams, gfp);
2423                if (!asoc->ssnmap)
2424                        goto clean_up;
2425
2426                error = sctp_assoc_set_id(asoc, gfp);
2427                if (error)
2428                        goto clean_up;
2429        }
2430
2431        /* ADDIP Section 4.1 ASCONF Chunk Procedures
2432         *
2433         * When an endpoint has an ASCONF signaled change to be sent to the
2434         * remote endpoint it should do the following:
2435         * ...
2436         * A2) A serial number should be assigned to the Chunk. The serial
2437         * number should be a monotonically increasing number. All serial
2438         * numbers are defined to be initialized at the start of the
2439         * association to the same value as the Initial TSN.
2440         */
2441        asoc->peer.addip_serial = asoc->peer.i.initial_tsn - 1;
2442        return 1;
2443
2444clean_up:
2445        /* Release the transport structures. */
2446        list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2447                transport = list_entry(pos, struct sctp_transport, transports);
2448                if (transport->state != SCTP_ACTIVE)
2449                        sctp_assoc_rm_peer(asoc, transport);
2450        }
2451
2452nomem:
2453        return 0;
2454}
2455
2456
2457/* Update asoc with the option described in param.
2458 *
2459 * RFC2960 3.3.2.1 Optional/Variable Length Parameters in INIT
2460 *
2461 * asoc is the association to update.
2462 * param is the variable length parameter to use for update.
2463 * cid tells us if this is an INIT, INIT ACK or COOKIE ECHO.
2464 * If the current packet is an INIT we want to minimize the amount of
2465 * work we do.  In particular, we should not build transport
2466 * structures for the addresses.
2467 */
2468static int sctp_process_param(struct sctp_association *asoc,
2469                              union sctp_params param,
2470                              const union sctp_addr *peer_addr,
2471                              gfp_t gfp)
2472{
2473        struct net *net = sock_net(asoc->base.sk);
2474        union sctp_addr addr;
2475        int i;
2476        __u16 sat;
2477        int retval = 1;
2478        sctp_scope_t scope;
2479        time_t stale;
2480        struct sctp_af *af;
2481        union sctp_addr_param *addr_param;
2482        struct sctp_transport *t;
2483
2484        /* We maintain all INIT parameters in network byte order all the
2485         * time.  This allows us to not worry about whether the parameters
2486         * came from a fresh INIT, and INIT ACK, or were stored in a cookie.
2487         */
2488        switch (param.p->type) {
2489        case SCTP_PARAM_IPV6_ADDRESS:
2490                if (PF_INET6 != asoc->base.sk->sk_family)
2491                        break;
2492                goto do_addr_param;
2493
2494        case SCTP_PARAM_IPV4_ADDRESS:
2495                /* v4 addresses are not allowed on v6-only socket */
2496                if (ipv6_only_sock(asoc->base.sk))
2497                        break;
2498do_addr_param:
2499                af = sctp_get_af_specific(param_type2af(param.p->type));
2500                af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
2501                scope = sctp_scope(peer_addr);
2502                if (sctp_in_scope(net, &addr, scope))
2503                        if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
2504                                return 0;
2505                break;
2506
2507        case SCTP_PARAM_COOKIE_PRESERVATIVE:
2508                if (!net->sctp.cookie_preserve_enable)
2509                        break;
2510
2511                stale = ntohl(param.life->lifespan_increment);
2512
2513                /* Suggested Cookie Life span increment's unit is msec,
2514                 * (1/1000sec).
2515                 */
2516                asoc->cookie_life.tv_sec += stale / 1000;
2517                asoc->cookie_life.tv_usec += (stale % 1000) * 1000;
2518                break;
2519
2520        case SCTP_PARAM_HOST_NAME_ADDRESS:
2521                SCTP_DEBUG_PRINTK("unimplemented SCTP_HOST_NAME_ADDRESS\n");
2522                break;
2523
2524        case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2525                /* Turn off the default values first so we'll know which
2526                 * ones are really set by the peer.
2527                 */
2528                asoc->peer.ipv4_address = 0;
2529                asoc->peer.ipv6_address = 0;
2530
2531                /* Assume that peer supports the address family
2532                 * by which it sends a packet.
2533                 */
2534                if (peer_addr->sa.sa_family == AF_INET6)
2535                        asoc->peer.ipv6_address = 1;
2536                else if (peer_addr->sa.sa_family == AF_INET)
2537                        asoc->peer.ipv4_address = 1;
2538
2539                /* Cycle through address types; avoid divide by 0. */
2540                sat = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2541                if (sat)
2542                        sat /= sizeof(__u16);
2543
2544                for (i = 0; i < sat; ++i) {
2545                        switch (param.sat->types[i]) {
2546                        case SCTP_PARAM_IPV4_ADDRESS:
2547                                asoc->peer.ipv4_address = 1;
2548                                break;
2549
2550                        case SCTP_PARAM_IPV6_ADDRESS:
2551                                if (PF_INET6 == asoc->base.sk->sk_family)
2552                                        asoc->peer.ipv6_address = 1;
2553                                break;
2554
2555                        case SCTP_PARAM_HOST_NAME_ADDRESS:
2556                                asoc->peer.hostname_address = 1;
2557                                break;
2558
2559                        default: /* Just ignore anything else.  */
2560                                break;
2561                        }
2562                }
2563                break;
2564
2565        case SCTP_PARAM_STATE_COOKIE:
2566                asoc->peer.cookie_len =
2567                        ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2568                asoc->peer.cookie = param.cookie->body;
2569                break;
2570
2571        case SCTP_PARAM_HEARTBEAT_INFO:
2572                /* Would be odd to receive, but it causes no problems. */
2573                break;
2574
2575        case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2576                /* Rejected during verify stage. */
2577                break;
2578
2579        case SCTP_PARAM_ECN_CAPABLE:
2580                asoc->peer.ecn_capable = 1;
2581                break;
2582
2583        case SCTP_PARAM_ADAPTATION_LAYER_IND:
2584                asoc->peer.adaptation_ind = ntohl(param.aind->adaptation_ind);
2585                break;
2586
2587        case SCTP_PARAM_SET_PRIMARY:
2588                if (!net->sctp.addip_enable)
2589                        goto fall_through;
2590
2591                addr_param = param.v + sizeof(sctp_addip_param_t);
2592
2593                af = sctp_get_af_specific(param_type2af(param.p->type));
2594                af->from_addr_param(&addr, addr_param,
2595                                    htons(asoc->peer.port), 0);
2596
2597                /* if the address is invalid, we can't process it.
2598                 * XXX: see spec for what to do.
2599                 */
2600                if (!af->addr_valid(&addr, NULL, NULL))
2601                        break;
2602
2603                t = sctp_assoc_lookup_paddr(asoc, &addr);
2604                if (!t)
2605                        break;
2606
2607                sctp_assoc_set_primary(asoc, t);
2608                break;
2609
2610        case SCTP_PARAM_SUPPORTED_EXT:
2611                sctp_process_ext_param(asoc, param);
2612                break;
2613
2614        case SCTP_PARAM_FWD_TSN_SUPPORT:
2615                if (net->sctp.prsctp_enable) {
2616                        asoc->peer.prsctp_capable = 1;
2617                        break;
2618                }
2619                /* Fall Through */
2620                goto fall_through;
2621
2622        case SCTP_PARAM_RANDOM:
2623                if (!net->sctp.auth_enable)
2624                        goto fall_through;
2625
2626                /* Save peer's random parameter */
2627                asoc->peer.peer_random = kmemdup(param.p,
2628                                            ntohs(param.p->length), gfp);
2629                if (!asoc->peer.peer_random) {
2630                        retval = 0;
2631                        break;
2632                }
2633                break;
2634
2635        case SCTP_PARAM_HMAC_ALGO:
2636                if (!net->sctp.auth_enable)
2637                        goto fall_through;
2638
2639                /* Save peer's HMAC list */
2640                asoc->peer.peer_hmacs = kmemdup(param.p,
2641                                            ntohs(param.p->length), gfp);
2642                if (!asoc->peer.peer_hmacs) {
2643                        retval = 0;
2644                        break;
2645                }
2646
2647                /* Set the default HMAC the peer requested*/
2648                sctp_auth_asoc_set_default_hmac(asoc, param.hmac_algo);
2649                break;
2650
2651        case SCTP_PARAM_CHUNKS:
2652                if (!net->sctp.auth_enable)
2653                        goto fall_through;
2654
2655                asoc->peer.peer_chunks = kmemdup(param.p,
2656                                            ntohs(param.p->length), gfp);
2657                if (!asoc->peer.peer_chunks)
2658                        retval = 0;
2659                break;
2660fall_through:
2661        default:
2662                /* Any unrecognized parameters should have been caught
2663                 * and handled by sctp_verify_param() which should be
2664                 * called prior to this routine.  Simply log the error
2665                 * here.
2666                 */
2667                SCTP_DEBUG_PRINTK("Ignoring param: %d for association %p.\n",
2668                                  ntohs(param.p->type), asoc);
2669                break;
2670        }
2671
2672        return retval;
2673}
2674
2675/* Select a new verification tag.  */
2676__u32 sctp_generate_tag(const struct sctp_endpoint *ep)
2677{
2678        /* I believe that this random number generator complies with RFC1750.
2679         * A tag of 0 is reserved for special cases (e.g. INIT).
2680         */
2681        __u32 x;
2682
2683        do {
2684                get_random_bytes(&x, sizeof(__u32));
2685        } while (x == 0);
2686
2687        return x;
2688}
2689
2690/* Select an initial TSN to send during startup.  */
2691__u32 sctp_generate_tsn(const struct sctp_endpoint *ep)
2692{
2693        __u32 retval;
2694
2695        get_random_bytes(&retval, sizeof(__u32));
2696        return retval;
2697}
2698
2699/*
2700 * ADDIP 3.1.1 Address Configuration Change Chunk (ASCONF)
2701 *      0                   1                   2                   3
2702 *      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
2703 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2704 *     | Type = 0xC1   |  Chunk Flags  |      Chunk Length             |
2705 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2706 *     |                       Serial Number                           |
2707 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2708 *     |                    Address Parameter                          |
2709 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2710 *     |                     ASCONF Parameter #1                       |
2711 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2712 *     \                                                               \
2713 *     /                             ....                              /
2714 *     \                                                               \
2715 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2716 *     |                     ASCONF Parameter #N                       |
2717 *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2718 *
2719 * Address Parameter and other parameter will not be wrapped in this function
2720 */
2721static struct sctp_chunk *sctp_make_asconf(struct sctp_association *asoc,
2722                                           union sctp_addr *addr,
2723                                           int vparam_len)
2724{
2725        sctp_addiphdr_t asconf;
2726        struct sctp_chunk *retval;
2727        int length = sizeof(asconf) + vparam_len;
2728        union sctp_addr_param addrparam;
2729        int addrlen;
2730        struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
2731
2732        addrlen = af->to_addr_param(addr, &addrparam);
2733        if (!addrlen)
2734                return NULL;
2735        length += addrlen;
2736
2737        /* Create the chunk.  */
2738        retval = sctp_make_chunk(asoc, SCTP_CID_ASCONF, 0, length);
2739        if (!retval)
2740                return NULL;
2741
2742        asconf.serial = htonl(asoc->addip_serial++);
2743
2744        retval->subh.addip_hdr =
2745                sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2746        retval->param_hdr.v =
2747                sctp_addto_chunk(retval, addrlen, &addrparam);
2748
2749        return retval;
2750}
2751
2752/* ADDIP
2753 * 3.2.1 Add IP Address
2754 *      0                   1                   2                   3
2755 *      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
2756 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2757 *     |        Type = 0xC001          |    Length = Variable          |
2758 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2759 *     |               ASCONF-Request Correlation ID                   |
2760 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2761 *     |                       Address Parameter                       |
2762 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2763 *
2764 * 3.2.2 Delete IP Address
2765 *      0                   1                   2                   3
2766 *      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
2767 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2768 *     |        Type = 0xC002          |    Length = Variable          |
2769 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2770 *     |               ASCONF-Request Correlation ID                   |
2771 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2772 *     |                       Address Parameter                       |
2773 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2774 *
2775 */
2776struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *asoc,
2777                                              union sctp_addr         *laddr,
2778                                              struct sockaddr         *addrs,
2779                                              int                     addrcnt,
2780                                              __be16                  flags)
2781{
2782        sctp_addip_param_t      param;
2783        struct sctp_chunk       *retval;
2784        union sctp_addr_param   addr_param;
2785        union sctp_addr         *addr;
2786        void                    *addr_buf;
2787        struct sctp_af          *af;
2788        int                     paramlen = sizeof(param);
2789        int                     addr_param_len = 0;
2790        int                     totallen = 0;
2791        int                     i;
2792        int                     del_pickup = 0;
2793
2794        /* Get total length of all the address parameters. */
2795        addr_buf = addrs;
2796        for (i = 0; i < addrcnt; i++) {
2797                addr = addr_buf;
2798                af = sctp_get_af_specific(addr->v4.sin_family);
2799                addr_param_len = af->to_addr_param(addr, &addr_param);
2800
2801                totallen += paramlen;
2802                totallen += addr_param_len;
2803
2804                addr_buf += af->sockaddr_len;
2805                if (asoc->asconf_addr_del_pending && !del_pickup) {
2806                        /* reuse the parameter length from the same scope one */
2807                        totallen += paramlen;
2808                        totallen += addr_param_len;
2809                        del_pickup = 1;
2810                        SCTP_DEBUG_PRINTK("mkasconf_update_ip: picked same-scope del_pending addr, totallen for all addresses is %d\n", totallen);
2811                }
2812        }
2813
2814        /* Create an asconf chunk with the required length. */
2815        retval = sctp_make_asconf(asoc, laddr, totallen);
2816        if (!retval)
2817                return NULL;
2818
2819        /* Add the address parameters to the asconf chunk. */
2820        addr_buf = addrs;
2821        for (i = 0; i < addrcnt; i++) {
2822                addr = addr_buf;
2823                af = sctp_get_af_specific(addr->v4.sin_family);
2824                addr_param_len = af->to_addr_param(addr, &addr_param);
2825                param.param_hdr.type = flags;
2826                param.param_hdr.length = htons(paramlen + addr_param_len);
2827                param.crr_id = i;
2828
2829                sctp_addto_chunk(retval, paramlen, &param);
2830                sctp_addto_chunk(retval, addr_param_len, &addr_param);
2831
2832                addr_buf += af->sockaddr_len;
2833        }
2834        if (flags == SCTP_PARAM_ADD_IP && del_pickup) {
2835                addr = asoc->asconf_addr_del_pending;
2836                af = sctp_get_af_specific(addr->v4.sin_family);
2837                addr_param_len = af->to_addr_param(addr, &addr_param);
2838                param.param_hdr.type = SCTP_PARAM_DEL_IP;
2839                param.param_hdr.length = htons(paramlen + addr_param_len);
2840                param.crr_id = i;
2841
2842                sctp_addto_chunk(retval, paramlen, &param);
2843                sctp_addto_chunk(retval, addr_param_len, &addr_param);
2844        }
2845        return retval;
2846}
2847
2848/* ADDIP
2849 * 3.2.4 Set Primary IP Address
2850 *      0                   1                   2                   3
2851 *      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
2852 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2853 *     |        Type =0xC004           |    Length = Variable          |
2854 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2855 *     |               ASCONF-Request Correlation ID                   |
2856 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2857 *     |                       Address Parameter                       |
2858 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2859 *
2860 * Create an ASCONF chunk with Set Primary IP address parameter.
2861 */
2862struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
2863                                             union sctp_addr *addr)
2864{
2865        sctp_addip_param_t      param;
2866        struct sctp_chunk       *retval;
2867        int                     len = sizeof(param);
2868        union sctp_addr_param   addrparam;
2869        int                     addrlen;
2870        struct sctp_af          *af = sctp_get_af_specific(addr->v4.sin_family);
2871
2872        addrlen = af->to_addr_param(addr, &addrparam);
2873        if (!addrlen)
2874                return NULL;
2875        len += addrlen;
2876
2877        /* Create the chunk and make asconf header. */
2878        retval = sctp_make_asconf(asoc, addr, len);
2879        if (!retval)
2880                return NULL;
2881
2882        param.param_hdr.type = SCTP_PARAM_SET_PRIMARY;
2883        param.param_hdr.length = htons(len);
2884        param.crr_id = 0;
2885
2886        sctp_addto_chunk(retval, sizeof(param), &param);
2887        sctp_addto_chunk(retval, addrlen, &addrparam);
2888
2889        return retval;
2890}
2891
2892/* ADDIP 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
2893 *      0                   1                   2                   3
2894 *      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
2895 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2896 *     | Type = 0x80   |  Chunk Flags  |      Chunk Length             |
2897 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2898 *     |                       Serial Number                           |
2899 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2900 *     |                 ASCONF Parameter Response#1                   |
2901 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2902 *     \                                                               \
2903 *     /                             ....                              /
2904 *     \                                                               \
2905 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2906 *     |                 ASCONF Parameter Response#N                   |
2907 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2908 *
2909 * Create an ASCONF_ACK chunk with enough space for the parameter responses.
2910 */
2911static struct sctp_chunk *sctp_make_asconf_ack(const struct sctp_association *asoc,
2912                                               __u32 serial, int vparam_len)
2913{
2914        sctp_addiphdr_t         asconf;
2915        struct sctp_chunk       *retval;
2916        int                     length = sizeof(asconf) + vparam_len;
2917
2918        /* Create the chunk.  */
2919        retval = sctp_make_chunk(asoc, SCTP_CID_ASCONF_ACK, 0, length);
2920        if (!retval)
2921                return NULL;
2922
2923        asconf.serial = htonl(serial);
2924
2925        retval->subh.addip_hdr =
2926                sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2927
2928        return retval;
2929}
2930
2931/* Add response parameters to an ASCONF_ACK chunk. */
2932static void sctp_add_asconf_response(struct sctp_chunk *chunk, __be32 crr_id,
2933                              __be16 err_code, sctp_addip_param_t *asconf_param)
2934{
2935        sctp_addip_param_t      ack_param;
2936        sctp_errhdr_t           err_param;
2937        int                     asconf_param_len = 0;
2938        int                     err_param_len = 0;
2939        __be16                  response_type;
2940
2941        if (SCTP_ERROR_NO_ERROR == err_code) {
2942                response_type = SCTP_PARAM_SUCCESS_REPORT;
2943        } else {
2944                response_type = SCTP_PARAM_ERR_CAUSE;
2945                err_param_len = sizeof(err_param);
2946                if (asconf_param)
2947                        asconf_param_len =
2948                                 ntohs(asconf_param->param_hdr.length);
2949        }
2950
2951        /* Add Success Indication or Error Cause Indication parameter. */
2952        ack_param.param_hdr.type = response_type;
2953        ack_param.param_hdr.length = htons(sizeof(ack_param) +
2954                                           err_param_len +
2955                                           asconf_param_len);
2956        ack_param.crr_id = crr_id;
2957        sctp_addto_chunk(chunk, sizeof(ack_param), &ack_param);
2958
2959        if (SCTP_ERROR_NO_ERROR == err_code)
2960                return;
2961
2962        /* Add Error Cause parameter. */
2963        err_param.cause = err_code;
2964        err_param.length = htons(err_param_len + asconf_param_len);
2965        sctp_addto_chunk(chunk, err_param_len, &err_param);
2966
2967        /* Add the failed TLV copied from ASCONF chunk. */
2968        if (asconf_param)
2969                sctp_addto_chunk(chunk, asconf_param_len, asconf_param);
2970}
2971
2972/* Process a asconf parameter. */
2973static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
2974                                       struct sctp_chunk *asconf,
2975                                       sctp_addip_param_t *asconf_param)
2976{
2977        struct sctp_transport *peer;
2978        struct sctp_af *af;
2979        union sctp_addr addr;
2980        union sctp_addr_param *addr_param;
2981
2982        addr_param = (void *)asconf_param + sizeof(sctp_addip_param_t);
2983
2984        if (asconf_param->param_hdr.type != SCTP_PARAM_ADD_IP &&
2985            asconf_param->param_hdr.type != SCTP_PARAM_DEL_IP &&
2986            asconf_param->param_hdr.type != SCTP_PARAM_SET_PRIMARY)
2987                return SCTP_ERROR_UNKNOWN_PARAM;
2988
2989        switch (addr_param->p.type) {
2990        case SCTP_PARAM_IPV6_ADDRESS:
2991                if (!asoc->peer.ipv6_address)
2992                        return SCTP_ERROR_DNS_FAILED;
2993                break;
2994        case SCTP_PARAM_IPV4_ADDRESS:
2995                if (!asoc->peer.ipv4_address)
2996                        return SCTP_ERROR_DNS_FAILED;
2997                break;
2998        default:
2999                return SCTP_ERROR_DNS_FAILED;
3000        }
3001
3002        af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3003        if (unlikely(!af))
3004                return SCTP_ERROR_DNS_FAILED;
3005
3006        af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);
3007
3008        /* ADDIP 4.2.1  This parameter MUST NOT contain a broadcast
3009         * or multicast address.
3010         * (note: wildcard is permitted and requires special handling so
3011         *  make sure we check for that)
3012         */
3013        if (!af->is_any(&addr) && !af->addr_valid(&addr, NULL, asconf->skb))
3014                return SCTP_ERROR_DNS_FAILED;
3015
3016        switch (asconf_param->param_hdr.type) {
3017        case SCTP_PARAM_ADD_IP:
3018                /* Section 4.2.1:
3019                 * If the address 0.0.0.0 or ::0 is provided, the source
3020                 * address of the packet MUST be added.
3021                 */
3022                if (af->is_any(&addr))
3023                        memcpy(&addr, &asconf->source, sizeof(addr));
3024
3025                /* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
3026                 * request and does not have the local resources to add this
3027                 * new address to the association, it MUST return an Error
3028                 * Cause TLV set to the new error code 'Operation Refused
3029                 * Due to Resource Shortage'.
3030                 */
3031
3032                peer = sctp_assoc_add_peer(asoc, &addr, GFP_ATOMIC, SCTP_UNCONFIRMED);
3033                if (!peer)
3034                        return SCTP_ERROR_RSRC_LOW;
3035
3036                /* Start the heartbeat timer. */
3037                if (!mod_timer(&peer->hb_timer, sctp_transport_timeout(peer)))
3038                        sctp_transport_hold(peer);
3039                asoc->new_transport = peer;
3040                break;
3041        case SCTP_PARAM_DEL_IP:
3042                /* ADDIP 4.3 D7) If a request is received to delete the
3043                 * last remaining IP address of a peer endpoint, the receiver
3044                 * MUST send an Error Cause TLV with the error cause set to the
3045                 * new error code 'Request to Delete Last Remaining IP Address'.
3046                 */
3047                if (asoc->peer.transport_count == 1)
3048                        return SCTP_ERROR_DEL_LAST_IP;
3049
3050                /* ADDIP 4.3 D8) If a request is received to delete an IP
3051                 * address which is also the source address of the IP packet
3052                 * which contained the ASCONF chunk, the receiver MUST reject
3053                 * this request. To reject the request the receiver MUST send
3054                 * an Error Cause TLV set to the new error code 'Request to
3055                 * Delete Source IP Address'
3056                 */
3057                if (sctp_cmp_addr_exact(&asconf->source, &addr))
3058                        return SCTP_ERROR_DEL_SRC_IP;
3059
3060                /* Section 4.2.2
3061                 * If the address 0.0.0.0 or ::0 is provided, all
3062                 * addresses of the peer except the source address of the
3063                 * packet MUST be deleted.
3064                 */
3065                if (af->is_any(&addr)) {
3066                        sctp_assoc_set_primary(asoc, asconf->transport);
3067                        sctp_assoc_del_nonprimary_peers(asoc,
3068                                                        asconf->transport);
3069                } else
3070                        sctp_assoc_del_peer(asoc, &addr);
3071                break;
3072        case SCTP_PARAM_SET_PRIMARY:
3073                /* ADDIP Section 4.2.4
3074                 * If the address 0.0.0.0 or ::0 is provided, the receiver
3075                 * MAY mark the source address of the packet as its
3076                 * primary.
3077                 */
3078                if (af->is_any(&addr))
3079                        memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));
3080
3081                peer = sctp_assoc_lookup_paddr(asoc, &addr);
3082                if (!peer)
3083                        return SCTP_ERROR_DNS_FAILED;
3084
3085                sctp_assoc_set_primary(asoc, peer);
3086                break;
3087        }
3088
3089        return SCTP_ERROR_NO_ERROR;
3090}
3091
3092/* Verify the ASCONF packet before we process it.  */
3093int sctp_verify_asconf(const struct sctp_association *asoc,
3094                       struct sctp_paramhdr *param_hdr, void *chunk_end,
3095                       struct sctp_paramhdr **errp) {
3096        sctp_addip_param_t *asconf_param;
3097        union sctp_params param;
3098        int length, plen;
3099
3100        param.v = (sctp_paramhdr_t *) param_hdr;
3101        while (param.v <= chunk_end - sizeof(sctp_paramhdr_t)) {
3102                length = ntohs(param.p->length);
3103                *errp = param.p;
3104
3105                if (param.v > chunk_end - length ||
3106                    length < sizeof(sctp_paramhdr_t))
3107                        return 0;
3108
3109                switch (param.p->type) {
3110                case SCTP_PARAM_ADD_IP:
3111                case SCTP_PARAM_DEL_IP:
3112                case SCTP_PARAM_SET_PRIMARY:
3113                        asconf_param = (sctp_addip_param_t *)param.v;
3114                        plen = ntohs(asconf_param->param_hdr.length);
3115                        if (plen < sizeof(sctp_addip_param_t) +
3116                            sizeof(sctp_paramhdr_t))
3117                                return 0;
3118                        break;
3119                case SCTP_PARAM_SUCCESS_REPORT:
3120                case SCTP_PARAM_ADAPTATION_LAYER_IND:
3121                        if (length != sizeof(sctp_addip_param_t))
3122                                return 0;
3123
3124                        break;
3125                default:
3126                        break;
3127                }
3128
3129                param.v += WORD_ROUND(length);
3130        }
3131
3132        if (param.v != chunk_end)
3133                return 0;
3134
3135        return 1;
3136}
3137
3138/* Process an incoming ASCONF chunk with the next expected serial no. and
3139 * return an ASCONF_ACK chunk to be sent in response.
3140 */
3141struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
3142                                       struct sctp_chunk *asconf)
3143{
3144        sctp_addiphdr_t         *hdr;
3145        union sctp_addr_param   *addr_param;
3146        sctp_addip_param_t      *asconf_param;
3147        struct sctp_chunk       *asconf_ack;
3148
3149        __be16  err_code;
3150        int     length = 0;
3151        int     chunk_len;
3152        __u32   serial;
3153        int     all_param_pass = 1;
3154
3155        chunk_len = ntohs(asconf->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
3156        hdr = (sctp_addiphdr_t *)asconf->skb->data;
3157        serial = ntohl(hdr->serial);
3158
3159        /* Skip the addiphdr and store a pointer to address parameter.  */
3160        length = sizeof(sctp_addiphdr_t);
3161        addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3162        chunk_len -= length;
3163
3164        /* Skip the address parameter and store a pointer to the first
3165         * asconf parameter.
3166         */
3167        length = ntohs(addr_param->p.length);
3168        asconf_param = (void *)addr_param + length;
3169        chunk_len -= length;
3170
3171        /* create an ASCONF_ACK chunk.
3172         * Based on the definitions of parameters, we know that the size of
3173         * ASCONF_ACK parameters are less than or equal to the fourfold of ASCONF
3174         * parameters.
3175         */
3176        asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 4);
3177        if (!asconf_ack)
3178                goto done;
3179
3180        /* Process the TLVs contained within the ASCONF chunk. */
3181        while (chunk_len > 0) {
3182                err_code = sctp_process_asconf_param(asoc, asconf,
3183                                                     asconf_param);
3184                /* ADDIP 4.1 A7)
3185                 * If an error response is received for a TLV parameter,
3186                 * all TLVs with no response before the failed TLV are
3187                 * considered successful if not reported.  All TLVs after
3188                 * the failed response are considered unsuccessful unless
3189                 * a specific success indication is present for the parameter.
3190                 */
3191                if (SCTP_ERROR_NO_ERROR != err_code)
3192                        all_param_pass = 0;
3193
3194                if (!all_param_pass)
3195                        sctp_add_asconf_response(asconf_ack,
3196                                                 asconf_param->crr_id, err_code,
3197                                                 asconf_param);
3198
3199                /* ADDIP 4.3 D11) When an endpoint receiving an ASCONF to add
3200                 * an IP address sends an 'Out of Resource' in its response, it
3201                 * MUST also fail any subsequent add or delete requests bundled
3202                 * in the ASCONF.
3203                 */
3204                if (SCTP_ERROR_RSRC_LOW == err_code)
3205                        goto done;
3206
3207                /* Move to the next ASCONF param. */
3208                length = ntohs(asconf_param->param_hdr.length);
3209                asconf_param = (void *)asconf_param + length;
3210                chunk_len -= length;
3211        }
3212
3213done:
3214        asoc->peer.addip_serial++;
3215
3216        /* If we are sending a new ASCONF_ACK hold a reference to it in assoc
3217         * after freeing the reference to old asconf ack if any.
3218         */
3219        if (asconf_ack) {
3220                sctp_chunk_hold(asconf_ack);
3221                list_add_tail(&asconf_ack->transmitted_list,
3222                              &asoc->asconf_ack_list);
3223        }
3224
3225        return asconf_ack;
3226}
3227
3228/* Process a asconf parameter that is successfully acked. */
3229static void sctp_asconf_param_success(struct sctp_association *asoc,
3230                                     sctp_addip_param_t *asconf_param)
3231{
3232        struct sctp_af *af;
3233        union sctp_addr addr;
3234        struct sctp_bind_addr *bp = &asoc->base.bind_addr;
3235        union sctp_addr_param *addr_param;
3236        struct sctp_transport *transport;
3237        struct sctp_sockaddr_entry *saddr;
3238
3239        addr_param = (void *)asconf_param + sizeof(sctp_addip_param_t);
3240
3241        /* We have checked the packet before, so we do not check again. */
3242        af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3243        af->from_addr_param(&addr, addr_param, htons(bp->port), 0);
3244
3245        switch (asconf_param->param_hdr.type) {
3246        case SCTP_PARAM_ADD_IP:
3247                /* This is always done in BH context with a socket lock
3248                 * held, so the list can not change.
3249                 */
3250                local_bh_disable();
3251                list_for_each_entry(saddr, &bp->address_list, list) {
3252                        if (sctp_cmp_addr_exact(&saddr->a, &addr))
3253                                saddr->state = SCTP_ADDR_SRC;
3254                }
3255                local_bh_enable();
3256                list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3257                                transports) {
3258                        dst_release(transport->dst);
3259                        transport->dst = NULL;
3260                }
3261                break;
3262        case SCTP_PARAM_DEL_IP:
3263                local_bh_disable();
3264                sctp_del_bind_addr(bp, &addr);
3265                if (asoc->asconf_addr_del_pending != NULL &&
3266                    sctp_cmp_addr_exact(asoc->asconf_addr_del_pending, &addr)) {
3267                        kfree(asoc->asconf_addr_del_pending);
3268                        asoc->asconf_addr_del_pending = NULL;
3269                }
3270                local_bh_enable();
3271                list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3272                                transports) {
3273                        dst_release(transport->dst);
3274                        transport->dst = NULL;
3275                }
3276                break;
3277        default:
3278                break;
3279        }
3280}
3281
3282/* Get the corresponding ASCONF response error code from the ASCONF_ACK chunk
3283 * for the given asconf parameter.  If there is no response for this parameter,
3284 * return the error code based on the third argument 'no_err'.
3285 * ADDIP 4.1
3286 * A7) If an error response is received for a TLV parameter, all TLVs with no
3287 * response before the failed TLV are considered successful if not reported.
3288 * All TLVs after the failed response are considered unsuccessful unless a
3289 * specific success indication is present for the parameter.
3290 */
3291static __be16 sctp_get_asconf_response(struct sctp_chunk *asconf_ack,
3292                                      sctp_addip_param_t *asconf_param,
3293                                      int no_err)
3294{
3295        sctp_addip_param_t      *asconf_ack_param;
3296        sctp_errhdr_t           *err_param;
3297        int                     length;
3298        int                     asconf_ack_len;
3299        __be16                  err_code;
3300
3301        if (no_err)
3302                err_code = SCTP_ERROR_NO_ERROR;
3303        else
3304                err_code = SCTP_ERROR_REQ_REFUSED;
3305
3306        asconf_ack_len = ntohs(asconf_ack->chunk_hdr->length) -
3307                             sizeof(sctp_chunkhdr_t);
3308
3309        /* Skip the addiphdr from the asconf_ack chunk and store a pointer to
3310         * the first asconf_ack parameter.
3311         */
3312        length = sizeof(sctp_addiphdr_t);
3313        asconf_ack_param = (sctp_addip_param_t *)(asconf_ack->skb->data +
3314                                                  length);
3315        asconf_ack_len -= length;
3316
3317        while (asconf_ack_len > 0) {
3318                if (asconf_ack_param->crr_id == asconf_param->crr_id) {
3319                        switch(asconf_ack_param->param_hdr.type) {
3320                        case SCTP_PARAM_SUCCESS_REPORT:
3321                                return SCTP_ERROR_NO_ERROR;
3322                        case SCTP_PARAM_ERR_CAUSE:
3323                                length = sizeof(sctp_addip_param_t);
3324                                err_param = (void *)asconf_ack_param + length;
3325                                asconf_ack_len -= length;
3326                                if (asconf_ack_len > 0)
3327                                        return err_param->cause;
3328                                else
3329                                        return SCTP_ERROR_INV_PARAM;
3330                                break;
3331                        default:
3332                                return SCTP_ERROR_INV_PARAM;
3333                        }
3334                }
3335
3336                length = ntohs(asconf_ack_param->param_hdr.length);
3337                asconf_ack_param = (void *)asconf_ack_param + length;
3338                asconf_ack_len -= length;
3339        }
3340
3341        return err_code;
3342}
3343
3344/* Process an incoming ASCONF_ACK chunk against the cached last ASCONF chunk. */
3345int sctp_process_asconf_ack(struct sctp_association *asoc,
3346                            struct sctp_chunk *asconf_ack)
3347{
3348        struct sctp_chunk       *asconf = asoc->addip_last_asconf;
3349        union sctp_addr_param   *addr_param;
3350        sctp_addip_param_t      *asconf_param;
3351        int     length = 0;
3352        int     asconf_len = asconf->skb->len;
3353        int     all_param_pass = 0;
3354        int     no_err = 1;
3355        int     retval = 0;
3356        __be16  err_code = SCTP_ERROR_NO_ERROR;
3357
3358        /* Skip the chunkhdr and addiphdr from the last asconf sent and store
3359         * a pointer to address parameter.
3360         */
3361        length = sizeof(sctp_addip_chunk_t);
3362        addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3363        asconf_len -= length;
3364
3365        /* Skip the address parameter in the last asconf sent and store a
3366         * pointer to the first asconf parameter.
3367         */
3368        length = ntohs(addr_param->p.length);
3369        asconf_param = (void *)addr_param + length;
3370        asconf_len -= length;
3371
3372        /* ADDIP 4.1
3373         * A8) If there is no response(s) to specific TLV parameter(s), and no
3374         * failures are indicated, then all request(s) are considered
3375         * successful.
3376         */
3377        if (asconf_ack->skb->len == sizeof(sctp_addiphdr_t))
3378                all_param_pass = 1;
3379
3380        /* Process the TLVs contained in the last sent ASCONF chunk. */
3381        while (asconf_len > 0) {
3382                if (all_param_pass)
3383                        err_code = SCTP_ERROR_NO_ERROR;
3384                else {
3385                        err_code = sctp_get_asconf_response(asconf_ack,
3386                                                            asconf_param,
3387                                                            no_err);
3388                        if (no_err && (SCTP_ERROR_NO_ERROR != err_code))
3389                                no_err = 0;
3390                }
3391
3392                switch (err_code) {
3393                case SCTP_ERROR_NO_ERROR:
3394                        sctp_asconf_param_success(asoc, asconf_param);
3395                        break;
3396
3397                case SCTP_ERROR_RSRC_LOW:
3398                        retval = 1;
3399                        break;
3400
3401                case SCTP_ERROR_UNKNOWN_PARAM:
3402                        /* Disable sending this type of asconf parameter in
3403                         * future.
3404                         */
3405                        asoc->peer.addip_disabled_mask |=
3406                                asconf_param->param_hdr.type;
3407                        break;
3408
3409                case SCTP_ERROR_REQ_REFUSED:
3410                case SCTP_ERROR_DEL_LAST_IP:
3411                case SCTP_ERROR_DEL_SRC_IP:
3412                default:
3413                         break;
3414                }
3415
3416                /* Skip the processed asconf parameter and move to the next
3417                 * one.
3418                 */
3419                length = ntohs(asconf_param->param_hdr.length);
3420                asconf_param = (void *)asconf_param + length;
3421                asconf_len -= length;
3422        }
3423
3424        if (no_err && asoc->src_out_of_asoc_ok) {
3425                asoc->src_out_of_asoc_ok = 0;
3426                sctp_transport_immediate_rtx(asoc->peer.primary_path);
3427        }
3428
3429        /* Free the cached last sent asconf chunk. */
3430        list_del_init(&asconf->transmitted_list);
3431        sctp_chunk_free(asconf);
3432        asoc->addip_last_asconf = NULL;
3433
3434        return retval;
3435}
3436
3437/* Make a FWD TSN chunk. */
3438struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
3439                                    __u32 new_cum_tsn, size_t nstreams,
3440                                    struct sctp_fwdtsn_skip *skiplist)
3441{
3442        struct sctp_chunk *retval = NULL;
3443        struct sctp_fwdtsn_hdr ftsn_hdr;
3444        struct sctp_fwdtsn_skip skip;
3445        size_t hint;
3446        int i;
3447
3448        hint = (nstreams + 1) * sizeof(__u32);
3449
3450        retval = sctp_make_chunk(asoc, SCTP_CID_FWD_TSN, 0, hint);
3451
3452        if (!retval)
3453                return NULL;
3454
3455        ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
3456        retval->subh.fwdtsn_hdr =
3457                sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
3458
3459        for (i = 0; i < nstreams; i++) {
3460                skip.stream = skiplist[i].stream;
3461                skip.ssn = skiplist[i].ssn;
3462                sctp_addto_chunk(retval, sizeof(skip), &skip);
3463        }
3464
3465        return retval;
3466}
3467
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