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        sctp_inithdr_t init;
 202        union sctp_params addrs;
 203        size_t chunksize;
 204        struct sctp_chunk *retval = NULL;
 205        int num_types, addrs_len = 0;
 206        struct sctp_sock *sp;
 207        sctp_supported_addrs_param_t sat;
 208        __be16 types[2];
 209        sctp_adaptation_ind_param_t aiparam;
 210        sctp_supported_ext_param_t ext_param;
 211        int num_ext = 0;
 212        __u8 extensions[3];
 213        sctp_paramhdr_t *auth_chunks = NULL,
 214                        *auth_hmacs = NULL;
 215
 216        /* RFC 2960 3.3.2 Initiation (INIT) (1)
 217         *
 218         * Note 1: The INIT chunks can contain multiple addresses that
 219         * can be IPv4 and/or IPv6 in any combination.
 220         */
 221        retval = NULL;
 222
 223        /* Convert the provided bind address list to raw format. */
 224        addrs = sctp_bind_addrs_to_raw(bp, &addrs_len, gfp);
 225
 226        init.init_tag              = htonl(asoc->c.my_vtag);
 227        init.a_rwnd                = htonl(asoc->rwnd);
 228        init.num_outbound_streams  = htons(asoc->c.sinit_num_ostreams);
 229        init.num_inbound_streams   = htons(asoc->c.sinit_max_instreams);
 230        init.initial_tsn           = htonl(asoc->c.initial_tsn);
 231
 232        /* How many address types are needed? */
 233        sp = sctp_sk(asoc->base.sk);
 234        num_types = sp->pf->supported_addrs(sp, types);
 235
 236        chunksize = sizeof(init) + addrs_len;
 237        chunksize += WORD_ROUND(SCTP_SAT_LEN(num_types));
 238        chunksize += sizeof(ecap_param);
 239
 240        if (sctp_prsctp_enable)
 241                chunksize += sizeof(prsctp_param);
 242
 243        /* ADDIP: Section 4.2.7:
 244         *  An implementation supporting this extension [ADDIP] MUST list
 245         *  the ASCONF,the ASCONF-ACK, and the AUTH  chunks in its INIT and
 246         *  INIT-ACK parameters.
 247         */
 248        if (sctp_addip_enable) {
 249                extensions[num_ext] = SCTP_CID_ASCONF;
 250                extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
 251                num_ext += 2;
 252        }
 253
 254        if (sp->adaptation_ind)
 255                chunksize += sizeof(aiparam);
 256
 257        chunksize += vparam_len;
 258
 259        /* Account for AUTH related parameters */
 260        if (sctp_auth_enable) {
 261                /* Add random parameter length*/
 262                chunksize += sizeof(asoc->c.auth_random);
 263
 264                /* Add HMACS parameter length if any were defined */
 265                auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
 266                if (auth_hmacs->length)
 267                        chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
 268                else
 269                        auth_hmacs = NULL;
 270
 271                /* Add CHUNKS parameter length */
 272                auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
 273                if (auth_chunks->length)
 274                        chunksize += WORD_ROUND(ntohs(auth_chunks->length));
 275                else
 276                        auth_chunks = NULL;
 277
 278                extensions[num_ext] = SCTP_CID_AUTH;
 279                num_ext += 1;
 280        }
 281
 282        /* If we have any extensions to report, account for that */
 283        if (num_ext)
 284                chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) +
 285                                        num_ext);
 286
 287        /* RFC 2960 3.3.2 Initiation (INIT) (1)
 288         *
 289         * Note 3: An INIT chunk MUST NOT contain more than one Host
 290         * Name address parameter. Moreover, the sender of the INIT
 291         * MUST NOT combine any other address types with the Host Name
 292         * address in the INIT. The receiver of INIT MUST ignore any
 293         * other address types if the Host Name address parameter is
 294         * present in the received INIT chunk.
 295         *
 296         * PLEASE DO NOT FIXME [This version does not support Host Name.]
 297         */
 298
 299        retval = sctp_make_chunk(asoc, SCTP_CID_INIT, 0, chunksize);
 300        if (!retval)
 301                goto nodata;
 302
 303        retval->subh.init_hdr =
 304                sctp_addto_chunk(retval, sizeof(init), &init);
 305        retval->param_hdr.v =
 306                sctp_addto_chunk(retval, addrs_len, addrs.v);
 307
 308        /* RFC 2960 3.3.2 Initiation (INIT) (1)
 309         *
 310         * Note 4: This parameter, when present, specifies all the
 311         * address types the sending endpoint can support. The absence
 312         * of this parameter indicates that the sending endpoint can
 313         * support any address type.
 314         */
 315        sat.param_hdr.type = SCTP_PARAM_SUPPORTED_ADDRESS_TYPES;
 316        sat.param_hdr.length = htons(SCTP_SAT_LEN(num_types));
 317        sctp_addto_chunk(retval, sizeof(sat), &sat);
 318        sctp_addto_chunk(retval, num_types * sizeof(__u16), &types);
 319
 320        sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
 321
 322        /* Add the supported extensions parameter.  Be nice and add this
 323         * fist before addiding the parameters for the extensions themselves
 324         */
 325        if (num_ext) {
 326                ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
 327                ext_param.param_hdr.length =
 328                            htons(sizeof(sctp_supported_ext_param_t) + num_ext);
 329                sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
 330                                &ext_param);
 331                sctp_addto_param(retval, num_ext, extensions);
 332        }
 333
 334        if (sctp_prsctp_enable)
 335                sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
 336
 337        if (sp->adaptation_ind) {
 338                aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
 339                aiparam.param_hdr.length = htons(sizeof(aiparam));
 340                aiparam.adaptation_ind = htonl(sp->adaptation_ind);
 341                sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
 342        }
 343
 344        /* Add SCTP-AUTH chunks to the parameter list */
 345        if (sctp_auth_enable) {
 346                sctp_addto_chunk(retval, sizeof(asoc->c.auth_random),
 347                                 asoc->c.auth_random);
 348                if (auth_hmacs)
 349                        sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
 350                                        auth_hmacs);
 351                if (auth_chunks)
 352                        sctp_addto_chunk(retval, ntohs(auth_chunks->length),
 353                                        auth_chunks);
 354        }
 355nodata:
 356        kfree(addrs.v);
 357        return retval;
 358}
 359
 360struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc,
 361                                 const struct sctp_chunk *chunk,
 362                                 gfp_t gfp, int unkparam_len)
 363{
 364        sctp_inithdr_t initack;
 365        struct sctp_chunk *retval;
 366        union sctp_params addrs;
 367        struct sctp_sock *sp;
 368        int addrs_len;
 369        sctp_cookie_param_t *cookie;
 370        int cookie_len;
 371        size_t chunksize;
 372        sctp_adaptation_ind_param_t aiparam;
 373        sctp_supported_ext_param_t ext_param;
 374        int num_ext = 0;
 375        __u8 extensions[3];
 376        sctp_paramhdr_t *auth_chunks = NULL,
 377                        *auth_hmacs = NULL,
 378                        *auth_random = NULL;
 379
 380        retval = NULL;
 381
 382        /* Note: there may be no addresses to embed. */
 383        addrs = sctp_bind_addrs_to_raw(&asoc->base.bind_addr, &addrs_len, gfp);
 384
 385        initack.init_tag                = htonl(asoc->c.my_vtag);
 386        initack.a_rwnd                  = htonl(asoc->rwnd);
 387        initack.num_outbound_streams    = htons(asoc->c.sinit_num_ostreams);
 388        initack.num_inbound_streams     = htons(asoc->c.sinit_max_instreams);
 389        initack.initial_tsn             = htonl(asoc->c.initial_tsn);
 390
 391        /* FIXME:  We really ought to build the cookie right
 392         * into the packet instead of allocating more fresh memory.
 393         */
 394        cookie = sctp_pack_cookie(asoc->ep, asoc, chunk, &cookie_len,
 395                                  addrs.v, addrs_len);
 396        if (!cookie)
 397                goto nomem_cookie;
 398
 399        /* Calculate the total size of allocation, include the reserved
 400         * space for reporting unknown parameters if it is specified.
 401         */
 402        sp = sctp_sk(asoc->base.sk);
 403        chunksize = sizeof(initack) + addrs_len + cookie_len + unkparam_len;
 404
 405        /* Tell peer that we'll do ECN only if peer advertised such cap.  */
 406        if (asoc->peer.ecn_capable)
 407                chunksize += sizeof(ecap_param);
 408
 409        if (asoc->peer.prsctp_capable)
 410                chunksize += sizeof(prsctp_param);
 411
 412        if (asoc->peer.asconf_capable) {
 413                extensions[num_ext] = SCTP_CID_ASCONF;
 414                extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
 415                num_ext += 2;
 416        }
 417
 418        if (sp->adaptation_ind)
 419                chunksize += sizeof(aiparam);
 420
 421        if (asoc->peer.auth_capable) {
 422                auth_random = (sctp_paramhdr_t *)asoc->c.auth_random;
 423                chunksize += ntohs(auth_random->length);
 424
 425                auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
 426                if (auth_hmacs->length)
 427                        chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
 428                else
 429                        auth_hmacs = NULL;
 430
 431                auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
 432                if (auth_chunks->length)
 433                        chunksize += WORD_ROUND(ntohs(auth_chunks->length));
 434                else
 435                        auth_chunks = NULL;
 436
 437                extensions[num_ext] = SCTP_CID_AUTH;
 438                num_ext += 1;
 439        }
 440
 441        if (num_ext)
 442                chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) +
 443                                        num_ext);
 444
 445        /* Now allocate and fill out the chunk.  */
 446        retval = sctp_make_chunk(asoc, SCTP_CID_INIT_ACK, 0, chunksize);
 447        if (!retval)
 448                goto nomem_chunk;
 449
 450        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
 451         *
 452         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 453         * HEARTBEAT ACK, * etc.) to the same destination transport
 454         * address from which it received the DATA or control chunk
 455         * to which it is replying.
 456         *
 457         * [INIT ACK back to where the INIT came from.]
 458         */
 459        retval->transport = chunk->transport;
 460
 461        retval->subh.init_hdr =
 462                sctp_addto_chunk(retval, sizeof(initack), &initack);
 463        retval->param_hdr.v = sctp_addto_chunk(retval, addrs_len, addrs.v);
 464        sctp_addto_chunk(retval, cookie_len, cookie);
 465        if (asoc->peer.ecn_capable)
 466                sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
 467        if (num_ext) {
 468                ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
 469                ext_param.param_hdr.length =
 470                            htons(sizeof(sctp_supported_ext_param_t) + num_ext);
 471                sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
 472                                 &ext_param);
 473                sctp_addto_param(retval, num_ext, extensions);
 474        }
 475        if (asoc->peer.prsctp_capable)
 476                sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
 477
 478        if (sp->adaptation_ind) {
 479                aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
 480                aiparam.param_hdr.length = htons(sizeof(aiparam));
 481                aiparam.adaptation_ind = htonl(sp->adaptation_ind);
 482                sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
 483        }
 484
 485        if (asoc->peer.auth_capable) {
 486                sctp_addto_chunk(retval, ntohs(auth_random->length),
 487                                 auth_random);
 488                if (auth_hmacs)
 489                        sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
 490                                        auth_hmacs);
 491                if (auth_chunks)
 492                        sctp_addto_chunk(retval, ntohs(auth_chunks->length),
 493                                        auth_chunks);
 494        }
 495
 496        /* We need to remove the const qualifier at this point.  */
 497        retval->asoc = (struct sctp_association *) asoc;
 498
 499nomem_chunk:
 500        kfree(cookie);
 501nomem_cookie:
 502        kfree(addrs.v);
 503        return retval;
 504}
 505
 506/* 3.3.11 Cookie Echo (COOKIE ECHO) (10):
 507 *
 508 * This chunk is used only during the initialization of an association.
 509 * It is sent by the initiator of an association to its peer to complete
 510 * the initialization process. This chunk MUST precede any DATA chunk
 511 * sent within the association, but MAY be bundled with one or more DATA
 512 * chunks in the same packet.
 513 *
 514 *      0                   1                   2                   3
 515 *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 516 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 517 *     |   Type = 10   |Chunk  Flags   |         Length                |
 518 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 519 *     /                     Cookie                                    /
 520 *     \                                                               \
 521 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 522 *
 523 * Chunk Flags: 8 bit
 524 *
 525 *   Set to zero on transmit and ignored on receipt.
 526 *
 527 * Length: 16 bits (unsigned integer)
 528 *
 529 *   Set to the size of the chunk in bytes, including the 4 bytes of
 530 *   the chunk header and the size of the Cookie.
 531 *
 532 * Cookie: variable size
 533 *
 534 *   This field must contain the exact cookie received in the
 535 *   State Cookie parameter from the previous INIT ACK.
 536 *
 537 *   An implementation SHOULD make the cookie as small as possible
 538 *   to insure interoperability.
 539 */
 540struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *asoc,
 541                                    const struct sctp_chunk *chunk)
 542{
 543        struct sctp_chunk *retval;
 544        void *cookie;
 545        int cookie_len;
 546
 547        cookie = asoc->peer.cookie;
 548        cookie_len = asoc->peer.cookie_len;
 549
 550        /* Build a cookie echo chunk.  */
 551        retval = sctp_make_chunk(asoc, SCTP_CID_COOKIE_ECHO, 0, cookie_len);
 552        if (!retval)
 553                goto nodata;
 554        retval->subh.cookie_hdr =
 555                sctp_addto_chunk(retval, cookie_len, cookie);
 556
 557        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
 558         *
 559         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 560         * HEARTBEAT ACK, * etc.) to the same destination transport
 561         * address from which it * received the DATA or control chunk
 562         * to which it is replying.
 563         *
 564         * [COOKIE ECHO back to where the INIT ACK came from.]
 565         */
 566        if (chunk)
 567                retval->transport = chunk->transport;
 568
 569nodata:
 570        return retval;
 571}
 572
 573/* 3.3.12 Cookie Acknowledgement (COOKIE ACK) (11):
 574 *
 575 * This chunk is used only during the initialization of an
 576 * association.  It is used to acknowledge the receipt of a COOKIE
 577 * ECHO chunk.  This chunk MUST precede any DATA or SACK chunk sent
 578 * within the association, but MAY be bundled with one or more DATA
 579 * chunks or SACK chunk in the same SCTP packet.
 580 *
 581 *      0                   1                   2                   3
 582 *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 583 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 584 *     |   Type = 11   |Chunk  Flags   |     Length = 4                |
 585 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 586 *
 587 * Chunk Flags: 8 bits
 588 *
 589 *   Set to zero on transmit and ignored on receipt.
 590 */
 591struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *asoc,
 592                                   const struct sctp_chunk *chunk)
 593{
 594        struct sctp_chunk *retval;
 595
 596        retval = sctp_make_chunk(asoc, SCTP_CID_COOKIE_ACK, 0, 0);
 597
 598        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
 599         *
 600         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 601         * HEARTBEAT ACK, * etc.) to the same destination transport
 602         * address from which it * received the DATA or control chunk
 603         * to which it is replying.
 604         *
 605         * [COOKIE ACK back to where the COOKIE ECHO came from.]
 606         */
 607        if (retval && chunk)
 608                retval->transport = chunk->transport;
 609
 610        return retval;
 611}
 612
 613/*
 614 *  Appendix A: Explicit Congestion Notification:
 615 *  CWR:
 616 *
 617 *  RFC 2481 details a specific bit for a sender to send in the header of
 618 *  its next outbound TCP segment to indicate to its peer that it has
 619 *  reduced its congestion window.  This is termed the CWR bit.  For
 620 *  SCTP the same indication is made by including the CWR chunk.
 621 *  This chunk contains one data element, i.e. the TSN number that
 622 *  was sent in the ECNE chunk.  This element represents the lowest
 623 *  TSN number in the datagram that was originally marked with the
 624 *  CE bit.
 625 *
 626 *     0                   1                   2                   3
 627 *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 628 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 629 *    | Chunk Type=13 | Flags=00000000|    Chunk Length = 8           |
 630 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 631 *    |                      Lowest TSN Number                        |
 632 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 633 *
 634 *     Note: The CWR is considered a Control chunk.
 635 */
 636struct sctp_chunk *sctp_make_cwr(const struct sctp_association *asoc,
 637                            const __u32 lowest_tsn,
 638                            const struct sctp_chunk *chunk)
 639{
 640        struct sctp_chunk *retval;
 641        sctp_cwrhdr_t cwr;
 642
 643        cwr.lowest_tsn = htonl(lowest_tsn);
 644        retval = sctp_make_chunk(asoc, SCTP_CID_ECN_CWR, 0,
 645                                 sizeof(sctp_cwrhdr_t));
 646
 647        if (!retval)
 648                goto nodata;
 649
 650        retval->subh.ecn_cwr_hdr =
 651                sctp_addto_chunk(retval, sizeof(cwr), &cwr);
 652
 653        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
 654         *
 655         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 656         * HEARTBEAT ACK, * etc.) to the same destination transport
 657         * address from which it * received the DATA or control chunk
 658         * to which it is replying.
 659         *
 660         * [Report a reduced congestion window back to where the ECNE
 661         * came from.]
 662         */
 663        if (chunk)
 664                retval->transport = chunk->transport;
 665
 666nodata:
 667        return retval;
 668}
 669
 670/* Make an ECNE chunk.  This is a congestion experienced report.  */
 671struct sctp_chunk *sctp_make_ecne(const struct sctp_association *asoc,
 672                             const __u32 lowest_tsn)
 673{
 674        struct sctp_chunk *retval;
 675        sctp_ecnehdr_t ecne;
 676
 677        ecne.lowest_tsn = htonl(lowest_tsn);
 678        retval = sctp_make_chunk(asoc, SCTP_CID_ECN_ECNE, 0,
 679                                 sizeof(sctp_ecnehdr_t));
 680        if (!retval)
 681                goto nodata;
 682        retval->subh.ecne_hdr =
 683                sctp_addto_chunk(retval, sizeof(ecne), &ecne);
 684
 685nodata:
 686        return retval;
 687}
 688
 689/* Make a DATA chunk for the given association from the provided
 690 * parameters.  However, do not populate the data payload.
 691 */
 692struct sctp_chunk *sctp_make_datafrag_empty(struct sctp_association *asoc,
 693                                       const struct sctp_sndrcvinfo *sinfo,
 694                                       int data_len, __u8 flags, __u16 ssn)
 695{
 696        struct sctp_chunk *retval;
 697        struct sctp_datahdr dp;
 698        int chunk_len;
 699
 700        /* We assign the TSN as LATE as possible, not here when
 701         * creating the chunk.
 702         */
 703        dp.tsn = 0;
 704        dp.stream = htons(sinfo->sinfo_stream);
 705        dp.ppid   = sinfo->sinfo_ppid;
 706
 707        /* Set the flags for an unordered send.  */
 708        if (sinfo->sinfo_flags & SCTP_UNORDERED) {
 709                flags |= SCTP_DATA_UNORDERED;
 710                dp.ssn = 0;
 711        } else
 712                dp.ssn = htons(ssn);
 713
 714        chunk_len = sizeof(dp) + data_len;
 715        retval = sctp_make_chunk(asoc, SCTP_CID_DATA, flags, chunk_len);
 716        if (!retval)
 717                goto nodata;
 718
 719        retval->subh.data_hdr = sctp_addto_chunk(retval, sizeof(dp), &dp);
 720        memcpy(&retval->sinfo, sinfo, sizeof(struct sctp_sndrcvinfo));
 721
 722nodata:
 723        return retval;
 724}
 725
 726/* Create a selective ackowledgement (SACK) for the given
 727 * association.  This reports on which TSN's we've seen to date,
 728 * including duplicates and gaps.
 729 */
 730struct sctp_chunk *sctp_make_sack(const struct sctp_association *asoc)
 731{
 732        struct sctp_chunk *retval;
 733        struct sctp_sackhdr sack;
 734        int len;
 735        __u32 ctsn;
 736        __u16 num_gabs, num_dup_tsns;
 737        struct sctp_association *aptr = (struct sctp_association *)asoc;
 738        struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
 739        struct sctp_gap_ack_block gabs[SCTP_MAX_GABS];
 740        struct sctp_transport *trans;
 741
 742        memset(gabs, 0, sizeof(gabs));
 743        ctsn = sctp_tsnmap_get_ctsn(map);
 744        SCTP_DEBUG_PRINTK("sackCTSNAck sent:  0x%x.\n", ctsn);
 745
 746        /* How much room is needed in the chunk? */
 747        num_gabs = sctp_tsnmap_num_gabs(map, gabs);
 748        num_dup_tsns = sctp_tsnmap_num_dups(map);
 749
 750        /* Initialize the SACK header.  */
 751        sack.cum_tsn_ack            = htonl(ctsn);
 752        sack.a_rwnd                 = htonl(asoc->a_rwnd);
 753        sack.num_gap_ack_blocks     = htons(num_gabs);
 754        sack.num_dup_tsns           = htons(num_dup_tsns);
 755
 756        len = sizeof(sack)
 757                + sizeof(struct sctp_gap_ack_block) * num_gabs
 758                + sizeof(__u32) * num_dup_tsns;
 759
 760        /* Create the chunk.  */
 761        retval = sctp_make_chunk(asoc, SCTP_CID_SACK, 0, len);
 762        if (!retval)
 763                goto nodata;
 764
 765        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
 766         *
 767         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 768         * HEARTBEAT ACK, etc.) to the same destination transport
 769         * address from which it received the DATA or control chunk to
 770         * which it is replying.  This rule should also be followed if
 771         * the endpoint is bundling DATA chunks together with the
 772         * reply chunk.
 773         *
 774         * However, when acknowledging multiple DATA chunks received
 775         * in packets from different source addresses in a single
 776         * SACK, the SACK chunk may be transmitted to one of the
 777         * destination transport addresses from which the DATA or
 778         * control chunks being acknowledged were received.
 779         *
 780         * [BUG:  We do not implement the following paragraph.
 781         * Perhaps we should remember the last transport we used for a
 782         * SACK and avoid that (if possible) if we have seen any
 783         * duplicates. --piggy]
 784         *
 785         * When a receiver of a duplicate DATA chunk sends a SACK to a
 786         * multi- homed endpoint it MAY be beneficial to vary the
 787         * destination address and not use the source address of the
 788         * DATA chunk.  The reason being that receiving a duplicate
 789         * from a multi-homed endpoint might indicate that the return
 790         * path (as specified in the source address of the DATA chunk)
 791         * for the SACK is broken.
 792         *
 793         * [Send to the address from which we last received a DATA chunk.]
 794         */
 795        retval->transport = asoc->peer.last_data_from;
 796
 797        retval->subh.sack_hdr =
 798                sctp_addto_chunk(retval, sizeof(sack), &sack);
 799
 800        /* Add the gap ack block information.   */
 801        if (num_gabs)
 802                sctp_addto_chunk(retval, sizeof(__u32) * num_gabs,
 803                                 gabs);
 804
 805        /* Add the duplicate TSN information.  */
 806        if (num_dup_tsns)
 807                sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns,
 808                                 sctp_tsnmap_get_dups(map));
 809
 810        /* Once we have a sack generated, check to see what our sack
 811         * generation is, if its 0, reset the transports to 0, and reset
 812         * the association generation to 1
 813         *
 814         * The idea is that zero is never used as a valid generation for the
 815         * association so no transport will match after a wrap event like this,
 816         * Until the next sack
 817         */
 818        if (++aptr->peer.sack_generation == 0) {
 819                list_for_each_entry(trans, &asoc->peer.transport_addr_list,
 820                                    transports)
 821                        trans->sack_generation = 0;
 822                aptr->peer.sack_generation = 1;
 823        }
 824nodata:
 825        return retval;
 826}
 827
 828/* Make a SHUTDOWN chunk. */
 829struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
 830                                      const struct sctp_chunk *chunk)
 831{
 832        struct sctp_chunk *retval;
 833        sctp_shutdownhdr_t shut;
 834        __u32 ctsn;
 835
 836        ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
 837        shut.cum_tsn_ack = htonl(ctsn);
 838
 839        retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN, 0,
 840                                 sizeof(sctp_shutdownhdr_t));
 841        if (!retval)
 842                goto nodata;
 843
 844        retval->subh.shutdown_hdr =
 845                sctp_addto_chunk(retval, sizeof(shut), &shut);
 846
 847        if (chunk)
 848                retval->transport = chunk->transport;
 849nodata:
 850        return retval;
 851}
 852
 853struct sctp_chunk *sctp_make_shutdown_ack(const struct sctp_association *asoc,
 854                                     const struct sctp_chunk *chunk)
 855{
 856        struct sctp_chunk *retval;
 857
 858        retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN_ACK, 0, 0);
 859
 860        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
 861         *
 862         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 863         * HEARTBEAT ACK, * etc.) to the same destination transport
 864         * address from which it * received the DATA or control chunk
 865         * to which it is replying.
 866         *
 867         * [ACK back to where the SHUTDOWN came from.]
 868         */
 869        if (retval && chunk)
 870                retval->transport = chunk->transport;
 871
 872        return retval;
 873}
 874
 875struct sctp_chunk *sctp_make_shutdown_complete(
 876        const struct sctp_association *asoc,
 877        const struct sctp_chunk *chunk)
 878{
 879        struct sctp_chunk *retval;
 880        __u8 flags = 0;
 881
 882        /* Set the T-bit if we have no association (vtag will be
 883         * reflected)
 884         */
 885        flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;
 886
 887        retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags, 0);
 888
 889        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
 890         *
 891         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 892         * HEARTBEAT ACK, * etc.) to the same destination transport
 893         * address from which it * received the DATA or control chunk
 894         * to which it is replying.
 895         *
 896         * [Report SHUTDOWN COMPLETE back to where the SHUTDOWN ACK
 897         * came from.]
 898         */
 899        if (retval && chunk)
 900                retval->transport = chunk->transport;
 901
 902        return retval;
 903}
 904
 905/* Create an ABORT.  Note that we set the T bit if we have no
 906 * association, except when responding to an INIT (sctpimpguide 2.41).
 907 */
 908struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc,
 909                              const struct sctp_chunk *chunk,
 910                              const size_t hint)
 911{
 912        struct sctp_chunk *retval;
 913        __u8 flags = 0;
 914
 915        /* Set the T-bit if we have no association and 'chunk' is not
 916         * an INIT (vtag will be reflected).
 917         */
 918        if (!asoc) {
 919                if (chunk && chunk->chunk_hdr &&
 920                    chunk->chunk_hdr->type == SCTP_CID_INIT)
 921                        flags = 0;
 922                else
 923                        flags = SCTP_CHUNK_FLAG_T;
 924        }
 925
 926        retval = sctp_make_chunk(asoc, SCTP_CID_ABORT, flags, hint);
 927
 928        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
 929         *
 930         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 931         * HEARTBEAT ACK, * etc.) to the same destination transport
 932         * address from which it * received the DATA or control chunk
 933         * to which it is replying.
 934         *
 935         * [ABORT back to where the offender came from.]
 936         */
 937        if (retval && chunk)
 938                retval->transport = chunk->transport;
 939
 940        return retval;
 941}
 942
 943/* Helper to create ABORT with a NO_USER_DATA error.  */
 944struct sctp_chunk *sctp_make_abort_no_data(
 945        const struct sctp_association *asoc,
 946        const struct sctp_chunk *chunk, __u32 tsn)
 947{
 948        struct sctp_chunk *retval;
 949        __be32 payload;
 950
 951        retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t)
 952                                 + sizeof(tsn));
 953
 954        if (!retval)
 955                goto no_mem;
 956
 957        /* Put the tsn back into network byte order.  */
 958        payload = htonl(tsn);
 959        sctp_init_cause(retval, SCTP_ERROR_NO_DATA, sizeof(payload));
 960        sctp_addto_chunk(retval, sizeof(payload), (const void *)&payload);
 961
 962        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
 963         *
 964         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
 965         * HEARTBEAT ACK, * etc.) to the same destination transport
 966         * address from which it * received the DATA or control chunk
 967         * to which it is replying.
 968         *
 969         * [ABORT back to where the offender came from.]
 970         */
 971        if (chunk)
 972                retval->transport = chunk->transport;
 973
 974no_mem:
 975        return retval;
 976}
 977
 978/* Helper to create ABORT with a SCTP_ERROR_USER_ABORT error.  */
 979struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *asoc,
 980                                        const struct msghdr *msg,
 981                                        size_t paylen)
 982{
 983        struct sctp_chunk *retval;
 984        void *payload = NULL;
 985        int err;
 986
 987        retval = sctp_make_abort(asoc, NULL, sizeof(sctp_errhdr_t) + paylen);
 988        if (!retval)
 989                goto err_chunk;
 990
 991        if (paylen) {
 992                /* Put the msg_iov together into payload.  */
 993                payload = kmalloc(paylen, GFP_KERNEL);
 994                if (!payload)
 995                        goto err_payload;
 996
 997                err = memcpy_fromiovec(payload, msg->msg_iov, paylen);
 998                if (err < 0)
 999                        goto err_copy;
1000        }
1001
1002        sctp_init_cause(retval, SCTP_ERROR_USER_ABORT, paylen);
1003        sctp_addto_chunk(retval, paylen, payload);
1004
1005        if (paylen)
1006                kfree(payload);
1007
1008        return retval;
1009
1010err_copy:
1011        kfree(payload);
1012err_payload:
1013        sctp_chunk_free(retval);
1014        retval = NULL;
1015err_chunk:
1016        return retval;
1017}
1018
1019/* Append bytes to the end of a parameter.  Will panic if chunk is not big
1020 * enough.
1021 */
1022static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
1023                              const void *data)
1024{
1025        void *target;
1026        int chunklen = ntohs(chunk->chunk_hdr->length);
1027
1028        target = skb_put(chunk->skb, len);
1029
1030        if (data)
1031                memcpy(target, data, len);
1032        else
1033                memset(target, 0, len);
1034
1035        /* Adjust the chunk length field.  */
1036        chunk->chunk_hdr->length = htons(chunklen + len);
1037        chunk->chunk_end = skb_tail_pointer(chunk->skb);
1038
1039        return target;
1040}
1041
1042/* Make an ABORT chunk with a PROTOCOL VIOLATION cause code. */
1043struct sctp_chunk *sctp_make_abort_violation(
1044        const struct sctp_association *asoc,
1045        const struct sctp_chunk *chunk,
1046        const __u8   *payload,
1047        const size_t paylen)
1048{
1049        struct sctp_chunk  *retval;
1050        struct sctp_paramhdr phdr;
1051
1052        retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t) + paylen
1053                                        + sizeof(sctp_paramhdr_t));
1054        if (!retval)
1055                goto end;
1056
1057        sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, paylen
1058                                        + sizeof(sctp_paramhdr_t));
1059
1060        phdr.type = htons(chunk->chunk_hdr->type);
1061        phdr.length = chunk->chunk_hdr->length;
1062        sctp_addto_chunk(retval, paylen, payload);
1063        sctp_addto_param(retval, sizeof(sctp_paramhdr_t), &phdr);
1064
1065end:
1066        return retval;
1067}
1068
1069struct sctp_chunk *sctp_make_violation_paramlen(
1070        const struct sctp_association *asoc,
1071        const struct sctp_chunk *chunk,
1072        struct sctp_paramhdr *param)
1073{
1074        struct sctp_chunk *retval;
1075        static const char error[] = "The following parameter had invalid length:";
1076        size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t) +
1077                                sizeof(sctp_paramhdr_t);
1078
1079        retval = sctp_make_abort(asoc, chunk, payload_len);
1080        if (!retval)
1081                goto nodata;
1082
1083        sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION,
1084                        sizeof(error) + sizeof(sctp_paramhdr_t));
1085        sctp_addto_chunk(retval, sizeof(error), error);
1086        sctp_addto_param(retval, sizeof(sctp_paramhdr_t), param);
1087
1088nodata:
1089        return retval;
1090}
1091
1092/* Make a HEARTBEAT chunk.  */
1093struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
1094                                  const struct sctp_transport *transport)
1095{
1096        struct sctp_chunk *retval;
1097        sctp_sender_hb_info_t hbinfo;
1098
1099        retval = sctp_make_chunk(asoc, SCTP_CID_HEARTBEAT, 0, sizeof(hbinfo));
1100
1101        if (!retval)
1102                goto nodata;
1103
1104        hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO;
1105        hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t));
1106        hbinfo.daddr = transport->ipaddr;
1107        hbinfo.sent_at = jiffies;
1108        hbinfo.hb_nonce = transport->hb_nonce;
1109
1110        /* Cast away the 'const', as this is just telling the chunk
1111         * what transport it belongs to.
1112         */
1113        retval->transport = (struct sctp_transport *) transport;
1114        retval->subh.hbs_hdr = sctp_addto_chunk(retval, sizeof(hbinfo),
1115                                                &hbinfo);
1116
1117nodata:
1118        return retval;
1119}
1120
1121struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc,
1122                                      const struct sctp_chunk *chunk,
1123                                      const void *payload, const size_t paylen)
1124{
1125        struct sctp_chunk *retval;
1126
1127        retval  = sctp_make_chunk(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen);
1128        if (!retval)
1129                goto nodata;
1130
1131        retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);
1132
1133        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
1134         *
1135         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1136         * HEARTBEAT ACK, * etc.) to the same destination transport
1137         * address from which it * received the DATA or control chunk
1138         * to which it is replying.
1139         *
1140         * [HBACK back to where the HEARTBEAT came from.]
1141         */
1142        if (chunk)
1143                retval->transport = chunk->transport;
1144
1145nodata:
1146        return retval;
1147}
1148
1149/* Create an Operation Error chunk with the specified space reserved.
1150 * This routine can be used for containing multiple causes in the chunk.
1151 */
1152static struct sctp_chunk *sctp_make_op_error_space(
1153        const struct sctp_association *asoc,
1154        const struct sctp_chunk *chunk,
1155        size_t size)
1156{
1157        struct sctp_chunk *retval;
1158
1159        retval = sctp_make_chunk(asoc, SCTP_CID_ERROR, 0,
1160                                 sizeof(sctp_errhdr_t) + size);
1161        if (!retval)
1162                goto nodata;
1163
1164        /* RFC 2960 6.4 Multi-homed SCTP Endpoints
1165         *
1166         * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1167         * HEARTBEAT ACK, etc.) to the same destination transport
1168         * address from which it received the DATA or control chunk
1169         * to which it is replying.
1170         *
1171         */
1172        if (chunk)
1173                retval->transport = chunk->transport;
1174
1175nodata:
1176        return retval;
1177}
1178
1179/* Create an Operation Error chunk of a fixed size,
1180 * specifically, max(asoc->pathmtu, SCTP_DEFAULT_MAXSEGMENT)
1181 * This is a helper function to allocate an error chunk for
1182 * for those invalid parameter codes in which we may not want
1183 * to report all the errors, if the incomming chunk is large
1184 */
1185static inline struct sctp_chunk *sctp_make_op_error_fixed(
1186        const struct sctp_association *asoc,
1187        const struct sctp_chunk *chunk)
1188{
1189        size_t size = asoc ? asoc->pathmtu : 0;
1190
1191        if (!size)
1192                size = SCTP_DEFAULT_MAXSEGMENT;
1193
1194        return sctp_make_op_error_space(asoc, chunk, size);
1195}
1196
1197/* Create an Operation Error chunk.  */
1198struct sctp_chunk *sctp_make_op_error(const struct sctp_association *asoc,
1199                                 const struct sctp_chunk *chunk,
1200                                 __be16 cause_code, const void *payload,
1201                                 size_t paylen, size_t reserve_tail)
1202{
1203        struct sctp_chunk *retval;
1204
1205        retval = sctp_make_op_error_space(asoc, chunk, paylen + reserve_tail);
1206        if (!retval)
1207                goto nodata;
1208
1209        sctp_init_cause(retval, cause_code, paylen + reserve_tail);
1210        sctp_addto_chunk(retval, paylen, payload);
1211        if (reserve_tail)
1212                sctp_addto_param(retval, reserve_tail, NULL);
1213
1214nodata:
1215        return retval;
1216}
1217
1218struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc)
1219{
1220        struct sctp_chunk *retval;
1221        struct sctp_hmac *hmac_desc;
1222        struct sctp_authhdr auth_hdr;
1223        __u8 *hmac;
1224
1225        /* Get the first hmac that the peer told us to use */
1226        hmac_desc = sctp_auth_asoc_get_hmac(asoc);
1227        if (unlikely(!hmac_desc))
1228                return NULL;
1229
1230        retval = sctp_make_chunk(asoc, SCTP_CID_AUTH, 0,
1231                        hmac_desc->hmac_len + sizeof(sctp_authhdr_t));
1232        if (!retval)
1233                return NULL;
1234
1235        auth_hdr.hmac_id = htons(hmac_desc->hmac_id);
1236        auth_hdr.shkey_id = htons(asoc->active_key_id);
1237
1238        retval->subh.auth_hdr = sctp_addto_chunk(retval, sizeof(sctp_authhdr_t),
1239                                                &auth_hdr);
1240
1241        hmac = skb_put(retval->skb, hmac_desc->hmac_len);
1242        memset(hmac, 0, hmac_desc->hmac_len);
1243
1244        /* Adjust the chunk header to include the empty MAC */
1245        retval->chunk_hdr->length =
1246                htons(ntohs(retval->chunk_hdr->length) + hmac_desc->hmac_len);
1247        retval->chunk_end = skb_tail_pointer(retval->skb);
1248
1249        return retval;
1250}
1251
1252
1253/********************************************************************
1254 * 2nd Level Abstractions
1255 ********************************************************************/
1256
1257/* Turn an skb into a chunk.
1258 * FIXME: Eventually move the structure directly inside the skb->cb[].
1259 */
1260struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
1261                            const struct sctp_association *asoc,
1262                            struct sock *sk)
1263{
1264        struct sctp_chunk *retval;
1265
1266        retval = kmem_cache_zalloc(sctp_chunk_cachep, GFP_ATOMIC);
1267
1268        if (!retval)
1269                goto nodata;
1270
1271        if (!sk) {
1272                SCTP_DEBUG_PRINTK("chunkifying skb %p w/o an sk\n", skb);
1273        }
1274
1275        INIT_LIST_HEAD(&retval->list);
1276        retval->skb             = skb;
1277        retval->asoc            = (struct sctp_association *)asoc;
1278        retval->has_tsn         = 0;
1279        retval->has_ssn         = 0;
1280        retval->rtt_in_progress = 0;
1281        retval->sent_at         = 0;
1282        retval->singleton       = 1;
1283        retval->end_of_packet   = 0;
1284        retval->ecn_ce_done     = 0;
1285        retval->pdiscard        = 0;
1286
1287        /* sctpimpguide-05.txt Section 2.8.2
1288         * M1) Each time a new DATA chunk is transmitted
1289         * set the 'TSN.Missing.Report' count for that TSN to 0. The
1290         * 'TSN.Missing.Report' count will be used to determine missing chunks
1291         * and when to fast retransmit.
1292         */
1293        retval->tsn_missing_report = 0;
1294        retval->tsn_gap_acked = 0;
1295        retval->fast_retransmit = SCTP_CAN_FRTX;
1296
1297        /* If this is a fragmented message, track all fragments
1298         * of the message (for SEND_FAILED).
1299         */
1300        retval->msg = NULL;
1301
1302        /* Polish the bead hole.  */
1303        INIT_LIST_HEAD(&retval->transmitted_list);
1304        INIT_LIST_HEAD(&retval->frag_list);
1305        SCTP_DBG_OBJCNT_INC(chunk);
1306        atomic_set(&retval->refcnt, 1);
1307
1308nodata:
1309        return retval;
1310}
1311
1312/* Set chunk->source and dest based on the IP header in chunk->skb.  */
1313void sctp_init_addrs(struct sctp_chunk *chunk, union sctp_addr *src,
1314                     union sctp_addr *dest)
1315{
1316        memcpy(&chunk->source, src, sizeof(union sctp_addr));
1317        memcpy(&chunk->dest, dest, sizeof(union sctp_addr));
1318}
1319
1320/* Extract the source address from a chunk.  */
1321const union sctp_addr *sctp_source(const struct sctp_chunk *chunk)
1322{
1323        /* If we have a known transport, use that.  */
1324        if (chunk->transport) {
1325                return &chunk->transport->ipaddr;
1326        } else {
1327                /* Otherwise, extract it from the IP header.  */
1328                return &chunk->source;
1329        }
1330}
1331
1332/* Create a new chunk, setting the type and flags headers from the
1333 * arguments, reserving enough space for a 'paylen' byte payload.
1334 */
1335SCTP_STATIC
1336struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc,
1337                                   __u8 type, __u8 flags, int paylen)
1338{
1339        struct sctp_chunk *retval;
1340        sctp_chunkhdr_t *chunk_hdr;
1341        struct sk_buff *skb;
1342        struct sock *sk;
1343
1344        /* No need to allocate LL here, as this is only a chunk. */
1345        skb = alloc_skb(WORD_ROUND(sizeof(sctp_chunkhdr_t) + paylen),
1346                        GFP_ATOMIC);
1347        if (!skb)
1348                goto nodata;
1349
1350        /* Make room for the chunk header.  */
1351        chunk_hdr = (sctp_chunkhdr_t *)skb_put(skb, sizeof(sctp_chunkhdr_t));
1352        chunk_hdr->type   = type;
1353        chunk_hdr->flags  = flags;
1354        chunk_hdr->length = htons(sizeof(sctp_chunkhdr_t));
1355
1356        sk = asoc ? asoc->base.sk : NULL;
1357        retval = sctp_chunkify(skb, asoc, sk);
1358        if (!retval) {
1359                kfree_skb(skb);
1360                goto nodata;
1361        }
1362
1363        retval->chunk_hdr = chunk_hdr;
1364        retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(struct sctp_chunkhdr);
1365
1366        /* Determine if the chunk needs to be authenticated */
1367        if (sctp_auth_send_cid(type, asoc))
1368                retval->auth = 1;
1369
1370        /* Set the skb to the belonging sock for accounting.  */
1371        skb->sk = sk;
1372
1373        return retval;
1374nodata:
1375        return NULL;
1376}
1377
1378
1379/* Release the memory occupied by a chunk.  */
1380static void sctp_chunk_destroy(struct sctp_chunk *chunk)
1381{
1382        BUG_ON(!list_empty(&chunk->list));
1383        list_del_init(&chunk->transmitted_list);
1384
1385        /* Free the chunk skb data and the SCTP_chunk stub itself. */
1386        dev_kfree_skb(chunk->skb);
1387
1388        SCTP_DBG_OBJCNT_DEC(chunk);
1389        kmem_cache_free(sctp_chunk_cachep, chunk);
1390}
1391
1392/* Possibly, free the chunk.  */
1393void sctp_chunk_free(struct sctp_chunk *chunk)
1394{
1395        /* Release our reference on the message tracker. */
1396        if (chunk->msg)
1397                sctp_datamsg_put(chunk->msg);
1398
1399        sctp_chunk_put(chunk);
1400}
1401
1402/* Grab a reference to the chunk. */
1403void sctp_chunk_hold(struct sctp_chunk *ch)
1404{
1405        atomic_inc(&ch->refcnt);
1406}
1407
1408/* Release a reference to the chunk. */
1409void sctp_chunk_put(struct sctp_chunk *ch)
1410{
1411        if (atomic_dec_and_test(&ch->refcnt))
1412                sctp_chunk_destroy(ch);
1413}
1414
1415/* Append bytes to the end of a chunk.  Will panic if chunk is not big
1416 * enough.
1417 */
1418void *sctp_addto_chunk(struct sctp_chunk *chunk, int len, const void *data)
1419{
1420        void *target;
1421        void *padding;
1422        int chunklen = ntohs(chunk->chunk_hdr->length);
1423        int padlen = WORD_ROUND(chunklen) - chunklen;
1424
1425        padding = skb_put(chunk->skb, padlen);
1426        target = skb_put(chunk->skb, len);
1427
1428        memset(padding, 0, padlen);
1429        memcpy(target, data, len);
1430
1431        /* Adjust the chunk length field.  */
1432        chunk->chunk_hdr->length = htons(chunklen + padlen + len);
1433        chunk->chunk_end = skb_tail_pointer(chunk->skb);
1434
1435        return target;
1436}
1437
1438/* Append bytes to the end of a chunk. Returns NULL if there isn't sufficient
1439 * space in the chunk
1440 */
1441void *sctp_addto_chunk_fixed(struct sctp_chunk *chunk,
1442                             int len, const void *data)
1443{
1444        if (skb_tailroom(chunk->skb) >= len)
1445                return sctp_addto_chunk(chunk, len, data);
1446        else
1447                return NULL;
1448}
1449
1450/* Append bytes from user space to the end of a chunk.  Will panic if
1451 * chunk is not big enough.
1452 * Returns a kernel err value.
1453 */
1454int sctp_user_addto_chunk(struct sctp_chunk *chunk, int off, int len,
1455                          struct iovec *data)
1456{
1457        __u8 *target;
1458        int err = 0;
1459
1460        /* Make room in chunk for data.  */
1461        target = skb_put(chunk->skb, len);
1462
1463        /* Copy data (whole iovec) into chunk */
1464        if ((err = memcpy_fromiovecend(target, data, off, len)))
1465                goto out;
1466
1467        /* Adjust the chunk length field.  */
1468        chunk->chunk_hdr->length =
1469                htons(ntohs(chunk->chunk_hdr->length) + len);
1470        chunk->chunk_end = skb_tail_pointer(chunk->skb);
1471
1472out:
1473        return err;
1474}
1475
1476/* Helper function to assign a TSN if needed.  This assumes that both
1477 * the data_hdr and association have already been assigned.
1478 */
1479void sctp_chunk_assign_ssn(struct sctp_chunk *chunk)
1480{
1481        struct sctp_datamsg *msg;
1482        struct sctp_chunk *lchunk;
1483        struct sctp_stream *stream;
1484        __u16 ssn;
1485        __u16 sid;
1486
1487        if (chunk->has_ssn)
1488                return;
1489
1490        /* All fragments will be on the same stream */
1491        sid = ntohs(chunk->subh.data_hdr->stream);
1492        stream = &chunk->asoc->ssnmap->out;
1493
1494        /* Now assign the sequence number to the entire message.
1495         * All fragments must have the same stream sequence number.
1496         */
1497        msg = chunk->msg;
1498        list_for_each_entry(lchunk, &msg->chunks, frag_list) {
1499                if (lchunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
1500                        ssn = 0;
1501                } else {
1502                        if (lchunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG)
1503                                ssn = sctp_ssn_next(stream, sid);
1504                        else
1505                                ssn = sctp_ssn_peek(stream, sid);
1506                }
1507
1508                lchunk->subh.data_hdr->ssn = htons(ssn);
1509                lchunk->has_ssn = 1;
1510        }
1511}
1512
1513/* Helper function to assign a TSN if needed.  This assumes that both
1514 * the data_hdr and association have already been assigned.
1515 */
1516void sctp_chunk_assign_tsn(struct sctp_chunk *chunk)
1517{
1518        if (!chunk->has_tsn) {
1519                /* This is the last possible instant to
1520                 * assign a TSN.
1521                 */
1522                chunk->subh.data_hdr->tsn =
1523                        htonl(sctp_association_get_next_tsn(chunk->asoc));
1524                chunk->has_tsn = 1;
1525        }
1526}
1527
1528/* Create a CLOSED association to use with an incoming packet.  */
1529struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *ep,
1530                                        struct sctp_chunk *chunk,
1531                                        gfp_t gfp)
1532{
1533        struct sctp_association *asoc;
1534        struct sk_buff *skb;
1535        sctp_scope_t scope;
1536        struct sctp_af *af;
1537
1538        /* Create the bare association.  */
1539        scope = sctp_scope(sctp_source(chunk));
1540        asoc = sctp_association_new(ep, ep->base.sk, scope, gfp);
1541        if (!asoc)
1542                goto nodata;
1543        asoc->temp = 1;
1544        skb = chunk->skb;
1545        /* Create an entry for the source address of the packet.  */
1546        af = sctp_get_af_specific(ipver2af(ip_hdr(skb)->version));
1547        if (unlikely(!af))
1548                goto fail;
1549        af->from_skb(&asoc->c.peer_addr, skb, 1);
1550nodata:
1551        return asoc;
1552
1553fail:
1554        sctp_association_free(asoc);
1555        return NULL;
1556}
1557
1558/* Build a cookie representing asoc.
1559 * This INCLUDES the param header needed to put the cookie in the INIT ACK.
1560 */
1561static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
1562                                      const struct sctp_association *asoc,
1563                                      const struct sctp_chunk *init_chunk,
1564                                      int *cookie_len,
1565                                      const __u8 *raw_addrs, int addrs_len)
1566{
1567        sctp_cookie_param_t *retval;
1568        struct sctp_signed_cookie *cookie;
1569        struct scatterlist sg;
1570        int headersize, bodysize;
1571        unsigned int keylen;
1572        char *key;
1573
1574        /* Header size is static data prior to the actual cookie, including
1575         * any padding.
1576         */
1577        headersize = sizeof(sctp_paramhdr_t) +
1578                     (sizeof(struct sctp_signed_cookie) -
1579                      sizeof(struct sctp_cookie));
1580        bodysize = sizeof(struct sctp_cookie)
1581                + ntohs(init_chunk->chunk_hdr->length) + addrs_len;
1582
1583        /* Pad out the cookie to a multiple to make the signature
1584         * functions simpler to write.
1585         */
1586        if (bodysize % SCTP_COOKIE_MULTIPLE)
1587                bodysize += SCTP_COOKIE_MULTIPLE
1588                        - (bodysize % SCTP_COOKIE_MULTIPLE);
1589        *cookie_len = headersize + bodysize;
1590
1591        /* Clear this memory since we are sending this data structure
1592         * out on the network.
1593         */
1594        retval = kzalloc(*cookie_len, GFP_ATOMIC);
1595        if (!retval)
1596                goto nodata;
1597
1598        cookie = (struct sctp_signed_cookie *) retval->body;
1599
1600        /* Set up the parameter header.  */
1601        retval->p.type = SCTP_PARAM_STATE_COOKIE;
1602        retval->p.length = htons(*cookie_len);
1603
1604        /* Copy the cookie part of the association itself.  */
1605        cookie->c = asoc->c;
1606        /* Save the raw address list length in the cookie. */
1607        cookie->c.raw_addr_list_len = addrs_len;
1608
1609        /* Remember PR-SCTP capability. */
1610        cookie->c.prsctp_capable = asoc->peer.prsctp_capable;
1611
1612        /* Save adaptation indication in the cookie. */
1613        cookie->c.adaptation_ind = asoc->peer.adaptation_ind;
1614
1615        /* Set an expiration time for the cookie.  */
1616        do_gettimeofday(&cookie->c.expiration);
1617        TIMEVAL_ADD(asoc->cookie_life, cookie->c.expiration);
1618
1619        /* Copy the peer's init packet.  */
1620        memcpy(&cookie->c.peer_init[0], init_chunk->chunk_hdr,
1621               ntohs(init_chunk->chunk_hdr->length));
1622
1623        /* Copy the raw local address list of the association. */
1624        memcpy((__u8 *)&cookie->c.peer_init[0] +
1625               ntohs(init_chunk->chunk_hdr->length), raw_addrs, addrs_len);
1626
1627        if (sctp_sk(ep->base.sk)->hmac) {
1628                struct hash_desc desc;
1629
1630                /* Sign the message.  */
1631                sg_init_one(&sg, &cookie->c, bodysize);
1632                keylen = SCTP_SECRET_SIZE;
1633                key = (char *)ep->secret_key[ep->current_key];
1634                desc.tfm = sctp_sk(ep->base.sk)->hmac;
1635                desc.flags = 0;
1636
1637                if (crypto_hash_setkey(desc.tfm, key, keylen) ||
1638                    crypto_hash_digest(&desc, &sg, bodysize, cookie->signature))
1639                        goto free_cookie;
1640        }
1641
1642        return retval;
1643
1644free_cookie:
1645        kfree(retval);
1646nodata:
1647        *cookie_len = 0;
1648        return NULL;
1649}
1650
1651/* Unpack the cookie from COOKIE ECHO chunk, recreating the association.  */
1652struct sctp_association *sctp_unpack_cookie(
1653        const struct sctp_endpoint *ep,
1654        const struct sctp_association *asoc,
1655        struct sctp_chunk *chunk, gfp_t gfp,
1656        int *error, struct sctp_chunk **errp)
1657{
1658        struct sctp_association *retval = NULL;
1659        struct sctp_signed_cookie *cookie;
1660        struct sctp_cookie *bear_cookie;
1661        int headersize, bodysize, fixed_size;
1662        __u8 *digest = ep->digest;
1663        struct scatterlist sg;
1664        unsigned int keylen, len;
1665        char *key;
1666        sctp_scope_t scope;
1667        struct sk_buff *skb = chunk->skb;
1668        struct timeval tv;
1669        struct hash_desc desc;
1670
1671        /* Header size is static data prior to the actual cookie, including
1672         * any padding.
1673         */
1674        headersize = sizeof(sctp_chunkhdr_t) +
1675                     (sizeof(struct sctp_signed_cookie) -
1676                      sizeof(struct sctp_cookie));
1677        bodysize = ntohs(chunk->chunk_hdr->length) - headersize;
1678        fixed_size = headersize + sizeof(struct sctp_cookie);
1679
1680        /* Verify that the chunk looks like it even has a cookie.
1681         * There must be enough room for our cookie and our peer's
1682         * INIT chunk.
1683         */
1684        len = ntohs(chunk->chunk_hdr->length);
1685        if (len < fixed_size + sizeof(struct sctp_chunkhdr))
1686                goto malformed;
1687
1688        /* Verify that the cookie has been padded out. */
1689        if (bodysize % SCTP_COOKIE_MULTIPLE)
1690                goto malformed;
1691
1692        /* Process the cookie.  */
1693        cookie = chunk->subh.cookie_hdr;
1694        bear_cookie = &cookie->c;
1695
1696        if (!sctp_sk(ep->base.sk)->hmac)
1697                goto no_hmac;
1698
1699        /* Check the signature.  */
1700        keylen = SCTP_SECRET_SIZE;
1701        sg_init_one(&sg, bear_cookie, bodysize);
1702        key = (char *)ep->secret_key[ep->current_key];
1703        desc.tfm = sctp_sk(ep->base.sk)->hmac;
1704        desc.flags = 0;
1705
1706        memset(digest, 0x00, SCTP_SIGNATURE_SIZE);
1707        if (crypto_hash_setkey(desc.tfm, key, keylen) ||
1708            crypto_hash_digest(&desc, &sg, bodysize, digest)) {
1709                *error = -SCTP_IERROR_NOMEM;
1710                goto fail;
1711        }
1712
1713        if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
1714                /* Try the previous key. */
1715                key = (char *)ep->secret_key[ep->last_key];
1716                memset(digest, 0x00, SCTP_SIGNATURE_SIZE);
1717                if (crypto_hash_setkey(desc.tfm, key, keylen) ||
1718                    crypto_hash_digest(&desc, &sg, bodysize, digest)) {
1719                        *error = -SCTP_IERROR_NOMEM;
1720                        goto fail;
1721                }
1722
1723                if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
1724                        /* Yikes!  Still bad signature! */
1725                        *error = -SCTP_IERROR_BAD_SIG;
1726                        goto fail;
1727                }
1728        }
1729
1730no_hmac:
1731        /* IG Section 2.35.2:
1732         *  3) Compare the port numbers and the verification tag contained
1733         *     within the COOKIE ECHO chunk to the actual port numbers and the
1734         *     verification tag within the SCTP common header of the received
1735         *     packet. If these values do not match the packet MUST be silently
1736         *     discarded,
1737         */
1738        if (ntohl(chunk->sctp_hdr->vtag) != bear_cookie->my_vtag) {
1739                *error = -SCTP_IERROR_BAD_TAG;
1740                goto fail;
1741        }
1742
1743        if (chunk->sctp_hdr->source != bear_cookie->peer_addr.v4.sin_port ||
1744            ntohs(chunk->sctp_hdr->dest) != bear_cookie->my_port) {
1745                *error = -SCTP_IERROR_BAD_PORTS;
1746                goto fail;
1747        }
1748
1749        /* Check to see if the cookie is stale.  If there is already
1750         * an association, there is no need to check cookie's expiration
1751         * for init collision case of lost COOKIE ACK.
1752         * If skb has been timestamped, then use the stamp, otherwise
1753         * use current time.  This introduces a small possibility that
1754         * that a cookie may be considered expired, but his would only slow
1755         * down the new association establishment instead of every packet.
1756         */
1757        if (sock_flag(ep->base.sk, SOCK_TIMESTAMP))
1758                skb_get_timestamp(skb, &tv);
1759        else
1760                do_gettimeofday(&tv);
1761
1762        if (!asoc && tv_lt(bear_cookie->expiration, tv)) {
1763                /*
1764                 * Section 3.3.10.3 Stale Cookie Error (3)
1765                 *
1766                 * Cause of error
1767                 * ---------------
1768                 * Stale Cookie Error:  Indicates the receipt of a valid State
1769                 * Cookie that has expired.
1770                 */
1771                len = ntohs(chunk->chunk_hdr->length);
1772                *errp = sctp_make_op_error_space(asoc, chunk, len);
1773                if (*errp) {
1774                        suseconds_t usecs = (tv.tv_sec -
1775                                bear_cookie->expiration.tv_sec) * 1000000L +
1776                                tv.tv_usec - bear_cookie->expiration.tv_usec;
1777                        __be32 n = htonl(usecs);
1778
1779                        sctp_init_cause(*errp, SCTP_ERROR_STALE_COOKIE,
1780                                        sizeof(n));
1781                        sctp_addto_chunk(*errp, sizeof(n), &n);
1782                        *error = -SCTP_IERROR_STALE_COOKIE;
1783                } else
1784                        *error = -SCTP_IERROR_NOMEM;
1785
1786                goto fail;
1787        }
1788
1789        /* Make a new base association.  */
1790        scope = sctp_scope(sctp_source(chunk));
1791        retval = sctp_association_new(ep, ep->base.sk, scope, gfp);
1792        if (!retval) {
1793                *error = -SCTP_IERROR_NOMEM;
1794                goto fail;
1795        }
1796
1797        /* Set up our peer's port number.  */
1798        retval->peer.port = ntohs(chunk->sctp_hdr->source);
1799
1800        /* Populate the association from the cookie.  */
1801        memcpy(&retval->c, bear_cookie, sizeof(*bear_cookie));
1802
1803        if (sctp_assoc_set_bind_addr_from_cookie(retval, bear_cookie,
1804                                                 GFP_ATOMIC) < 0) {
1805                *error = -SCTP_IERROR_NOMEM;
1806                goto fail;
1807        }
1808
1809        /* Also, add the destination address. */
1810        if (list_empty(&retval->base.bind_addr.address_list)) {
1811                sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest,
1812                                SCTP_ADDR_SRC, GFP_ATOMIC);
1813        }
1814
1815        retval->next_tsn = retval->c.initial_tsn;
1816        retval->ctsn_ack_point = retval->next_tsn - 1;
1817        retval->addip_serial = retval->c.initial_tsn;
1818        retval->adv_peer_ack_point = retval->ctsn_ack_point;
1819        retval->peer.prsctp_capable = retval->c.prsctp_capable;
1820        retval->peer.adaptation_ind = retval->c.adaptation_ind;
1821
1822        /* The INIT stuff will be done by the side effects.  */
1823        return retval;
1824
1825fail:
1826        if (retval)
1827                sctp_association_free(retval);
1828
1829        return NULL;
1830
1831malformed:
1832        /* Yikes!  The packet is either corrupt or deliberately
1833         * malformed.
1834         */
1835        *error = -SCTP_IERROR_MALFORMED;
1836        goto fail;
1837}
1838
1839/********************************************************************
1840 * 3rd Level Abstractions
1841 ********************************************************************/
1842
1843struct __sctp_missing {
1844        __be32 num_missing;
1845        __be16 type;
1846}  __packed;
1847
1848/*
1849 * Report a missing mandatory parameter.
1850 */
1851static int sctp_process_missing_param(const struct sctp_association *asoc,
1852                                      sctp_param_t paramtype,
1853                                      struct sctp_chunk *chunk,
1854                                      struct sctp_chunk **errp)
1855{
1856        struct __sctp_missing report;
1857        __u16 len;
1858
1859        len = WORD_ROUND(sizeof(report));
1860
1861        /* Make an ERROR chunk, preparing enough room for
1862         * returning multiple unknown parameters.
1863         */
1864        if (!*errp)
1865                *errp = sctp_make_op_error_space(asoc, chunk, len);
1866
1867        if (*errp) {
1868                report.num_missing = htonl(1);
1869                report.type = paramtype;
1870                sctp_init_cause(*errp, SCTP_ERROR_MISS_PARAM,
1871                                sizeof(report));
1872                sctp_addto_chunk(*errp, sizeof(report), &report);
1873        }
1874
1875        /* Stop processing this chunk. */
1876        return 0;
1877}
1878
1879/* Report an Invalid Mandatory Parameter.  */
1880static int sctp_process_inv_mandatory(const struct sctp_association *asoc,
1881                                      struct sctp_chunk *chunk,
1882                                      struct sctp_chunk **errp)
1883{
1884        /* Invalid Mandatory Parameter Error has no payload. */
1885
1886        if (!*errp)
1887                *errp = sctp_make_op_error_space(asoc, chunk, 0);
1888
1889        if (*errp)
1890                sctp_init_cause(*errp, SCTP_ERROR_INV_PARAM, 0);
1891
1892        /* Stop processing this chunk. */
1893        return 0;
1894}
1895
1896static int sctp_process_inv_paramlength(const struct sctp_association *asoc,
1897                                        struct sctp_paramhdr *param,
1898                                        const struct sctp_chunk *chunk,
1899                                        struct sctp_chunk **errp)
1900{
1901        /* This is a fatal error.  Any accumulated non-fatal errors are
1902         * not reported.
1903         */
1904        if (*errp)
1905                sctp_chunk_free(*errp);
1906
1907        /* Create an error chunk and fill it in with our payload. */
1908        *errp = sctp_make_violation_paramlen(asoc, chunk, param);
1909
1910        return 0;
1911}
1912
1913
1914/* Do not attempt to handle the HOST_NAME parm.  However, do
1915 * send back an indicator to the peer.
1916 */
1917static int sctp_process_hn_param(const struct sctp_association *asoc,
1918                                 union sctp_params param,
1919                                 struct sctp_chunk *chunk,
1920                                 struct sctp_chunk **errp)
1921{
1922        __u16 len = ntohs(param.p->length);
1923
1924        /* Processing of the HOST_NAME parameter will generate an
1925         * ABORT.  If we've accumulated any non-fatal errors, they
1926         * would be unrecognized parameters and we should not include
1927         * them in the ABORT.
1928         */
1929        if (*errp)
1930                sctp_chunk_free(*errp);
1931
1932        *errp = sctp_make_op_error_space(asoc, chunk, len);
1933
1934        if (*errp) {
1935                sctp_init_cause(*errp, SCTP_ERROR_DNS_FAILED, len);
1936                sctp_addto_chunk(*errp, len, param.v);
1937        }
1938
1939        /* Stop processing this chunk. */
1940        return 0;
1941}
1942
1943static int sctp_verify_ext_param(union sctp_params param)
1944{
1945        __u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
1946        int have_auth = 0;
1947        int have_asconf = 0;
1948        int i;
1949
1950        for (i = 0; i < num_ext; i++) {
1951                switch (param.ext->chunks[i]) {
1952                    case SCTP_CID_AUTH:
1953                            have_auth = 1;
1954                            break;
1955                    case SCTP_CID_ASCONF:
1956                    case SCTP_CID_ASCONF_ACK:
1957                            have_asconf = 1;
1958                            break;
1959                }
1960        }
1961
1962        /* ADD-IP Security: The draft requires us to ABORT or ignore the
1963         * INIT/INIT-ACK if ADD-IP is listed, but AUTH is not.  Do this
1964         * only if ADD-IP is turned on and we are not backward-compatible
1965         * mode.
1966         */
1967        if (sctp_addip_noauth)
1968                return 1;
1969
1970        if (sctp_addip_enable && !have_auth && have_asconf)
1971                return 0;
1972
1973        return 1;
1974}
1975
1976static void sctp_process_ext_param(struct sctp_association *asoc,
1977                                    union sctp_params param)
1978{
1979        __u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
1980        int i;
1981
1982        for (i = 0; i < num_ext; i++) {
1983                switch (param.ext->chunks[i]) {
1984                    case SCTP_CID_FWD_TSN:
1985                            if (sctp_prsctp_enable &&
1986                                !asoc->peer.prsctp_capable)
1987                                    asoc->peer.prsctp_capable = 1;
1988                            break;
1989                    case SCTP_CID_AUTH:
1990                            /* if the peer reports AUTH, assume that he
1991                             * supports AUTH.
1992                             */
1993                            if (sctp_auth_enable)
1994                                    asoc->peer.auth_capable = 1;
1995                            break;
1996                    case SCTP_CID_ASCONF:
1997                    case SCTP_CID_ASCONF_ACK:
1998                            if (sctp_addip_enable)
1999                                    asoc->peer.asconf_capable = 1;
2000                            break;
2001                    default:
2002                            break;
2003                }
2004        }
2005}
2006
2007/* RFC 3.2.1 & the Implementers Guide 2.2.
2008 *
2009 * The Parameter Types are encoded such that the
2010 * highest-order two bits specify the action that must be
2011 * taken if the processing endpoint does not recognize the
2012 * Parameter Type.
2013 *
2014 * 00 - Stop processing this parameter; do not process any further
2015 *      parameters within this chunk
2016 *
2017 * 01 - Stop processing this parameter, do not process any further
2018 *      parameters within this chunk, and report the unrecognized
2019 *      parameter in an 'Unrecognized Parameter' ERROR chunk.
2020 *
2021 * 10 - Skip this parameter and continue processing.
2022 *
2023 * 11 - Skip this parameter and continue processing but
2024 *      report the unrecognized parameter in an
2025 *      'Unrecognized Parameter' ERROR chunk.
2026 *
2027 * Return value:
2028 *      SCTP_IERROR_NO_ERROR - continue with the chunk
2029 *      SCTP_IERROR_ERROR    - stop and report an error.
2030 *      SCTP_IERROR_NOMEME   - out of memory.
2031 */
2032static sctp_ierror_t sctp_process_unk_param(const struct sctp_association *asoc,
2033                                            union sctp_params param,
2034                                            struct sctp_chunk *chunk,
2035                                            struct sctp_chunk **errp)
2036{
2037        int retval = SCTP_IERROR_NO_ERROR;
2038
2039        switch (param.p->type & SCTP_PARAM_ACTION_MASK) {
2040        case SCTP_PARAM_ACTION_DISCARD:
2041                retval =  SCTP_IERROR_ERROR;
2042                break;
2043        case SCTP_PARAM_ACTION_SKIP:
2044                break;
2045        case SCTP_PARAM_ACTION_DISCARD_ERR:
2046                retval =  SCTP_IERROR_ERROR;
2047                /* Fall through */
2048        case SCTP_PARAM_ACTION_SKIP_ERR:
2049                /* Make an ERROR chunk, preparing enough room for
2050                 * returning multiple unknown parameters.
2051                 */
2052                if (NULL == *errp)
2053                        *errp = sctp_make_op_error_fixed(asoc, chunk);
2054
2055                if (*errp) {
2056                        if (!sctp_init_cause_fixed(*errp, SCTP_ERROR_UNKNOWN_PARAM,
2057                                        WORD_ROUND(ntohs(param.p->length))))
2058                                sctp_addto_chunk_fixed(*errp,
2059                                                WORD_ROUND(ntohs(param.p->length)),
2060                                                param.v);
2061                } else {
2062                        /* If there is no memory for generating the ERROR
2063                         * report as specified, an ABORT will be triggered
2064                         * to the peer and the association won't be
2065                         * established.
2066                         */
2067                        retval = SCTP_IERROR_NOMEM;
2068                }
2069                break;
2070        default:
2071                break;
2072        }
2073
2074        return retval;
2075}
2076
2077/* Verify variable length parameters
2078 * Return values:
2079 *      SCTP_IERROR_ABORT - trigger an ABORT
2080 *      SCTP_IERROR_NOMEM - out of memory (abort)
2081 *      SCTP_IERROR_ERROR - stop processing, trigger an ERROR
2082 *      SCTP_IERROR_NO_ERROR - continue with the chunk
2083 */
2084static sctp_ierror_t sctp_verify_param(const struct sctp_association *asoc,
2085                                        union sctp_params param,
2086                                        sctp_cid_t cid,
2087                                        struct sctp_chunk *chunk,
2088                                        struct sctp_chunk **err_chunk)
2089{
2090        struct sctp_hmac_algo_param *hmacs;
2091        int retval = SCTP_IERROR_NO_ERROR;
2092        __u16 n_elt, id = 0;
2093        int i;
2094
2095        /* FIXME - This routine is not looking at each parameter per the
2096         * chunk type, i.e., unrecognized parameters should be further
2097         * identified based on the chunk id.
2098         */
2099
2100        switch (param.p->type) {
2101        case SCTP_PARAM_IPV4_ADDRESS:
2102        case SCTP_PARAM_IPV6_ADDRESS:
2103        case SCTP_PARAM_COOKIE_PRESERVATIVE:
2104        case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2105        case SCTP_PARAM_STATE_COOKIE:
2106        case SCTP_PARAM_HEARTBEAT_INFO:
2107        case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2108        case SCTP_PARAM_ECN_CAPABLE:
2109        case SCTP_PARAM_ADAPTATION_LAYER_IND:
2110                break;
2111
2112        case SCTP_PARAM_SUPPORTED_EXT:
2113                if (!sctp_verify_ext_param(param))
2114                        return SCTP_IERROR_ABORT;
2115                break;
2116
2117        case SCTP_PARAM_SET_PRIMARY:
2118                if (sctp_addip_enable)
2119                        break;
2120                goto fallthrough;
2121
2122        case SCTP_PARAM_HOST_NAME_ADDRESS:
2123                /* Tell the peer, we won't support this param.  */
2124                sctp_process_hn_param(asoc, param, chunk, err_chunk);
2125                retval = SCTP_IERROR_ABORT;
2126                break;
2127
2128        case SCTP_PARAM_FWD_TSN_SUPPORT:
2129                if (sctp_prsctp_enable)
2130                        break;
2131                goto fallthrough;
2132
2133        case SCTP_PARAM_RANDOM:
2134                if (!sctp_auth_enable)
2135                        goto fallthrough;
2136
2137                /* SCTP-AUTH: Secion 6.1
2138                 * If the random number is not 32 byte long the association
2139                 * MUST be aborted.  The ABORT chunk SHOULD contain the error
2140                 * cause 'Protocol Violation'.
2141                 */
2142                if (SCTP_AUTH_RANDOM_LENGTH !=
2143                        ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) {
2144                        sctp_process_inv_paramlength(asoc, param.p,
2145                                                        chunk, err_chunk);
2146                        retval = SCTP_IERROR_ABORT;
2147                }
2148                break;
2149
2150        case SCTP_PARAM_CHUNKS:
2151                if (!sctp_auth_enable)
2152                        goto fallthrough;
2153
2154                /* SCTP-AUTH: Section 3.2
2155                 * The CHUNKS parameter MUST be included once in the INIT or
2156                 *  INIT-ACK chunk if the sender wants to receive authenticated
2157                 *  chunks.  Its maximum length is 260 bytes.
2158                 */
2159                if (260 < ntohs(param.p->length)) {
2160                        sctp_process_inv_paramlength(asoc, param.p,
2161                                                     chunk, err_chunk);
2162                        retval = SCTP_IERROR_ABORT;
2163                }
2164                break;
2165
2166        case SCTP_PARAM_HMAC_ALGO:
2167                if (!sctp_auth_enable)
2168                        goto fallthrough;
2169
2170                hmacs = (struct sctp_hmac_algo_param *)param.p;
2171                n_elt = (ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) >> 1;
2172
2173                /* SCTP-AUTH: Section 6.1
2174                 * The HMAC algorithm based on SHA-1 MUST be supported and
2175                 * included in the HMAC-ALGO parameter.
2176                 */
2177                for (i = 0; i < n_elt; i++) {
2178                        id = ntohs(hmacs->hmac_ids[i]);
2179
2180                        if (id == SCTP_AUTH_HMAC_ID_SHA1)
2181                                break;
2182                }
2183
2184                if (id != SCTP_AUTH_HMAC_ID_SHA1) {
2185                        sctp_process_inv_paramlength(asoc, param.p, chunk,
2186                                                     err_chunk);
2187                        retval = SCTP_IERROR_ABORT;
2188                }
2189                break;
2190fallthrough:
2191        default:
2192                SCTP_DEBUG_PRINTK("Unrecognized param: %d for chunk %d.\n",
2193                                ntohs(param.p->type), cid);
2194                retval = sctp_process_unk_param(asoc, param, chunk, err_chunk);
2195                break;
2196        }
2197        return retval;
2198}
2199
2200/* Verify the INIT packet before we process it.  */
2201int sctp_verify_init(const struct sctp_association *asoc,
2202                     sctp_cid_t cid,
2203                     sctp_init_chunk_t *peer_init,
2204                     struct sctp_chunk *chunk,
2205                     struct sctp_chunk **errp)
2206{
2207        union sctp_params param;
2208        int has_cookie = 0;
2209        int result;
2210
2211        /* Verify stream values are non-zero. */
2212        if ((0 == peer_init->init_hdr.num_outbound_streams) ||
2213            (0 == peer_init->init_hdr.num_inbound_streams) ||
2214            (0 == peer_init->init_hdr.init_tag) ||
2215            (SCTP_DEFAULT_MINWINDOW > ntohl(peer_init->init_hdr.a_rwnd))) {
2216
2217                return sctp_process_inv_mandatory(asoc, chunk, errp);
2218        }
2219
2220        /* Check for missing mandatory parameters.  */
2221        sctp_walk_params(param, peer_init, init_hdr.params) {
2222
2223                if (SCTP_PARAM_STATE_COOKIE == param.p->type)
2224                        has_cookie = 1;
2225
2226        } /* for (loop through all parameters) */
2227
2228        /* There is a possibility that a parameter length was bad and
2229         * in that case we would have stoped walking the parameters.
2230         * The current param.p would point at the bad one.
2231         * Current consensus on the mailing list is to generate a PROTOCOL
2232         * VIOLATION error.  We build the ERROR chunk here and let the normal
2233         * error handling code build and send the packet.
2234         */
2235        if (param.v != (void*)chunk->chunk_end)
2236                return sctp_process_inv_paramlength(asoc, param.p, chunk, errp);
2237
2238        /* The only missing mandatory param possible today is
2239         * the state cookie for an INIT-ACK chunk.
2240         */
2241        if ((SCTP_CID_INIT_ACK == cid) && !has_cookie)
2242                return sctp_process_missing_param(asoc, SCTP_PARAM_STATE_COOKIE,
2243                                                  chunk, errp);
2244
2245        /* Verify all the variable length parameters */
2246        sctp_walk_params(param, peer_init, init_hdr.params) {
2247
2248                result = sctp_verify_param(asoc, param, cid, chunk, errp);
2249                switch (result) {
2250                    case SCTP_IERROR_ABORT:
2251                    case SCTP_IERROR_NOMEM:
2252                                return 0;
2253                    case SCTP_IERROR_ERROR:
2254                                return 1;
2255                    case SCTP_IERROR_NO_ERROR:
2256                    default:
2257                                break;
2258                }
2259
2260        } /* for (loop through all parameters) */
2261
2262        return 1;
2263}
2264
2265/* Unpack the parameters in an INIT packet into an association.
2266 * Returns 0 on failure, else success.
2267 * FIXME:  This is an association method.
2268 */
2269int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,
2270                      const union sctp_addr *peer_addr,
2271                      sctp_init_chunk_t *peer_init, gfp_t gfp)
2272{
2273        union sctp_params param;
2274        struct sctp_transport *transport;
2275        struct list_head *pos, *temp;
2276        struct sctp_af *af;
2277        union sctp_addr addr;
2278        char *cookie;
2279        int src_match = 0;
2280
2281        /* We must include the address that the INIT packet came from.
2282         * This is the only address that matters for an INIT packet.
2283         * When processing a COOKIE ECHO, we retrieve the from address
2284         * of the INIT from the cookie.
2285         */
2286
2287        /* This implementation defaults to making the first transport
2288         * added as the primary transport.  The source address seems to
2289         * be a a better choice than any of the embedded addresses.
2290         */
2291        if(!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
2292                goto nomem;
2293
2294        if (sctp_cmp_addr_exact(sctp_source(chunk), peer_addr))
2295                src_match = 1;
2296
2297        /* Process the initialization parameters.  */
2298        sctp_walk_params(param, peer_init, init_hdr.params) {
2299                if (!src_match && (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
2300                    param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
2301                        af = sctp_get_af_specific(param_type2af(param.p->type));
2302                        af->from_addr_param(&addr, param.addr,
2303                                            chunk->sctp_hdr->source, 0);
2304                        if (sctp_cmp_addr_exact(sctp_source(chunk), &addr))
2305                                src_match = 1;
2306                }
2307
2308                if (!sctp_process_param(asoc, param, peer_addr, gfp))
2309                        goto clean_up;
2310        }
2311
2312        /* source address of chunk may not match any valid address */
2313        if (!src_match)
2314                goto clean_up;
2315
2316        /* AUTH: After processing the parameters, make sure that we
2317         * have all the required info to potentially do authentications.
2318         */
2319        if (asoc->peer.auth_capable && (!asoc->peer.peer_random ||
2320                                        !asoc->peer.peer_hmacs))
2321                asoc->peer.auth_capable = 0;
2322
2323        /* In a non-backward compatible mode, if the peer claims
2324         * support for ADD-IP but not AUTH,  the ADD-IP spec states
2325         * that we MUST ABORT the association. Section 6.  The section
2326         * also give us an option to silently ignore the packet, which
2327         * is what we'll do here.
2328         */
2329        if (!sctp_addip_noauth &&
2330             (asoc->peer.asconf_capable && !asoc->peer.auth_capable)) {
2331                asoc->peer.addip_disabled_mask |= (SCTP_PARAM_ADD_IP |
2332                                                  SCTP_PARAM_DEL_IP |
2333                                                  SCTP_PARAM_SET_PRIMARY);
2334                asoc->peer.asconf_capable = 0;
2335                goto clean_up;
2336        }
2337
2338        /* Walk list of transports, removing transports in the UNKNOWN state. */
2339        list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2340                transport = list_entry(pos, struct sctp_transport, transports);
2341                if (transport->state == SCTP_UNKNOWN) {
2342                        sctp_assoc_rm_peer(asoc, transport);
2343                }
2344        }
2345
2346        /* The fixed INIT headers are always in network byte
2347         * order.
2348         */
2349        asoc->peer.i.init_tag =
2350                ntohl(peer_init->init_hdr.init_tag);
2351        asoc->peer.i.a_rwnd =
2352                ntohl(peer_init->init_hdr.a_rwnd);
2353        asoc->peer.i.num_outbound_streams =
2354                ntohs(peer_init->init_hdr.num_outbound_streams);
2355        asoc->peer.i.num_inbound_streams =
2356                ntohs(peer_init->init_hdr.num_inbound_streams);
2357        asoc->peer.i.initial_tsn =
2358                ntohl(peer_init->init_hdr.initial_tsn);
2359
2360        /* Apply the upper bounds for output streams based on peer's
2361         * number of inbound streams.
2362         */
2363        if (asoc->c.sinit_num_ostreams  >
2364            ntohs(peer_init->init_hdr.num_inbound_streams)) {
2365                asoc->c.sinit_num_ostreams =
2366                        ntohs(peer_init->init_hdr.num_inbound_streams);
2367        }
2368
2369        if (asoc->c.sinit_max_instreams >
2370            ntohs(peer_init->init_hdr.num_outbound_streams)) {
2371                asoc->c.sinit_max_instreams =
2372                        ntohs(peer_init->init_hdr.num_outbound_streams);
2373        }
2374
2375        /* Copy Initiation tag from INIT to VT_peer in cookie.   */
2376        asoc->c.peer_vtag = asoc->peer.i.init_tag;
2377
2378        /* Peer Rwnd   : Current calculated value of the peer's rwnd.  */
2379        asoc->peer.rwnd = asoc->peer.i.a_rwnd;
2380
2381        /* Copy cookie in case we need to resend COOKIE-ECHO. */
2382        cookie = asoc->peer.cookie;
2383        if (cookie) {
2384                asoc->peer.cookie = kmemdup(cookie, asoc->peer.cookie_len, gfp);
2385                if (!asoc->peer.cookie)
2386                        goto clean_up;
2387        }
2388
2389        /* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily
2390         * high (for example, implementations MAY use the size of the receiver
2391         * advertised window).
2392         */
2393        list_for_each_entry(transport, &asoc->peer.transport_addr_list,
2394                        transports) {
2395                transport->ssthresh = asoc->peer.i.a_rwnd;
2396        }
2397
2398        /* Set up the TSN tracking pieces.  */
2399        if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
2400                                asoc->peer.i.initial_tsn, gfp))
2401                goto clean_up;
2402
2403        /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
2404         *
2405         * The stream sequence number in all the streams shall start
2406         * from 0 when the association is established.  Also, when the
2407         * stream sequence number reaches the value 65535 the next
2408         * stream sequence number shall be set to 0.
2409         */
2410
2411        /* Allocate storage for the negotiated streams if it is not a temporary
2412         * association.
2413         */
2414        if (!asoc->temp) {
2415                int error;
2416
2417                asoc->ssnmap = sctp_ssnmap_new(asoc->c.sinit_max_instreams,
2418                                               asoc->c.sinit_num_ostreams, gfp);
2419                if (!asoc->ssnmap)
2420                        goto clean_up;
2421
2422                error = sctp_assoc_set_id(asoc, gfp);
2423                if (error)
2424                        goto clean_up;
2425        }
2426
2427        /* ADDIP Section 4.1 ASCONF Chunk Procedures
2428         *
2429         * When an endpoint has an ASCONF signaled change to be sent to the
2430         * remote endpoint it should do the following:
2431         * ...
2432         * A2) A serial number should be assigned to the Chunk. The serial
2433         * number should be a monotonically increasing number. All serial
2434         * numbers are defined to be initialized at the start of the
2435         * association to the same value as the Initial TSN.
2436         */
2437        asoc->peer.addip_serial = asoc->peer.i.initial_tsn - 1;
2438        return 1;
2439
2440clean_up:
2441        /* Release the transport structures. */
2442        list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2443                transport = list_entry(pos, struct sctp_transport, transports);
2444                if (transport->state != SCTP_ACTIVE)
2445                        sctp_assoc_rm_peer(asoc, transport);
2446        }
2447
2448nomem:
2449        return 0;
2450}
2451
2452
2453/* Update asoc with the option described in param.
2454 *
2455 * RFC2960 3.3.2.1 Optional/Variable Length Parameters in INIT
2456 *
2457 * asoc is the association to update.
2458 * param is the variable length parameter to use for update.
2459 * cid tells us if this is an INIT, INIT ACK or COOKIE ECHO.
2460 * If the current packet is an INIT we want to minimize the amount of
2461 * work we do.  In particular, we should not build transport
2462 * structures for the addresses.
2463 */
2464static int sctp_process_param(struct sctp_association *asoc,
2465                              union sctp_params param,
2466                              const union sctp_addr *peer_addr,
2467                              gfp_t gfp)
2468{
2469        union sctp_addr addr;
2470        int i;
2471        __u16 sat;
2472        int retval = 1;
2473        sctp_scope_t scope;
2474        time_t stale;
2475        struct sctp_af *af;
2476        union sctp_addr_param *addr_param;
2477        struct sctp_transport *t;
2478
2479        /* We maintain all INIT parameters in network byte order all the
2480         * time.  This allows us to not worry about whether the parameters
2481         * came from a fresh INIT, and INIT ACK, or were stored in a cookie.
2482         */
2483        switch (param.p->type) {
2484        case SCTP_PARAM_IPV6_ADDRESS:
2485                if (PF_INET6 != asoc->base.sk->sk_family)
2486                        break;
2487                goto do_addr_param;
2488
2489        case SCTP_PARAM_IPV4_ADDRESS:
2490                /* v4 addresses are not allowed on v6-only socket */
2491                if (ipv6_only_sock(asoc->base.sk))
2492                        break;
2493do_addr_param:
2494                af = sctp_get_af_specific(param_type2af(param.p->type));
2495                af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
2496                scope = sctp_scope(peer_addr);
2497                if (sctp_in_scope(&addr, scope))
2498                        if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
2499                                return 0;
2500                break;
2501
2502        case SCTP_PARAM_COOKIE_PRESERVATIVE:
2503                if (!sctp_cookie_preserve_enable)
2504                        break;
2505
2506                stale = ntohl(param.life->lifespan_increment);
2507
2508                /* Suggested Cookie Life span increment's unit is msec,
2509                 * (1/1000sec).
2510                 */
2511                asoc->cookie_life.tv_sec += stale / 1000;
2512                asoc->cookie_life.tv_usec += (stale % 1000) * 1000;
2513                break;
2514
2515        case SCTP_PARAM_HOST_NAME_ADDRESS:
2516                SCTP_DEBUG_PRINTK("unimplemented SCTP_HOST_NAME_ADDRESS\n");
2517                break;
2518
2519        case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2520                /* Turn off the default values first so we'll know which
2521                 * ones are really set by the peer.
2522                 */
2523                asoc->peer.ipv4_address = 0;
2524                asoc->peer.ipv6_address = 0;
2525
2526                /* Assume that peer supports the address family
2527                 * by which it sends a packet.
2528                 */
2529                if (peer_addr->sa.sa_family == AF_INET6)
2530                        asoc->peer.ipv6_address = 1;
2531                else if (peer_addr->sa.sa_family == AF_INET)
2532                        asoc->peer.ipv4_address = 1;
2533
2534                /* Cycle through address types; avoid divide by 0. */
2535                sat = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2536                if (sat)
2537                        sat /= sizeof(__u16);
2538
2539                for (i = 0; i < sat; ++i) {
2540                        switch (param.sat->types[i]) {
2541                        case SCTP_PARAM_IPV4_ADDRESS:
2542                                asoc->peer.ipv4_address = 1;
2543                                break;
2544
2545                        case SCTP_PARAM_IPV6_ADDRESS:
2546                                if (PF_INET6 == asoc->base.sk->sk_family)
2547                                        asoc->peer.ipv6_address = 1;
2548                                break;
2549
2550                        case SCTP_PARAM_HOST_NAME_ADDRESS:
2551                                asoc->peer.hostname_address = 1;
2552                                break;
2553
2554                        default: /* Just ignore anything else.  */
2555                                break;
2556                        }
2557                }
2558                break;
2559
2560        case SCTP_PARAM_STATE_COOKIE:
2561                asoc->peer.cookie_len =
2562                        ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
2563                asoc->peer.cookie = param.cookie->body;
2564                break;
2565
2566        case SCTP_PARAM_HEARTBEAT_INFO:
2567                /* Would be odd to receive, but it causes no problems. */
2568                break;
2569
2570        case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2571                /* Rejected during verify stage. */
2572                break;
2573
2574        case SCTP_PARAM_ECN_CAPABLE:
2575                asoc->peer.ecn_capable = 1;
2576                break;
2577
2578        case SCTP_PARAM_ADAPTATION_LAYER_IND:
2579                asoc->peer.adaptation_ind = ntohl(param.aind->adaptation_ind);
2580                break;
2581
2582        case SCTP_PARAM_SET_PRIMARY:
2583                if (!sctp_addip_enable)
2584                        goto fall_through;
2585
2586                addr_param = param.v + sizeof(sctp_addip_param_t);
2587
2588                af = sctp_get_af_specific(param_type2af(param.p->type));
2589                af->from_addr_param(&addr, addr_param,
2590                                    htons(asoc->peer.port), 0);
2591
2592                /* if the address is invalid, we can't process it.
2593                 * XXX: see spec for what to do.
2594                 */
2595                if (!af->addr_valid(&addr, NULL, NULL))
2596                        break;
2597
2598                t = sctp_assoc_lookup_paddr(asoc, &addr);
2599                if (!t)
2600                        break;
2601
2602                sctp_assoc_set_primary(asoc, t);
2603                break;
2604
2605        case SCTP_PARAM_SUPPORTED_EXT:
2606                sctp_process_ext_param(asoc, param);
2607                break;
2608
2609        case SCTP_PARAM_FWD_TSN_SUPPORT:
2610                if (sctp_prsctp_enable) {
2611                        asoc->peer.prsctp_capable = 1;
2612                        break;
2613                }
2614                /* Fall Through */
2615                goto fall_through;
2616
2617        case SCTP_PARAM_RANDOM:
2618                if (!sctp_auth_enable)
2619                        goto fall_through;
2620
2621                /* Save peer's random parameter */
2622                asoc->peer.peer_random = kmemdup(param.p,
2623                                            ntohs(param.p->length), gfp);
2624                if (!asoc->peer.peer_random) {
2625                        retval = 0;
2626                        break;
2627                }
2628                break;
2629
2630        case SCTP_PARAM_HMAC_ALGO:
2631                if (!sctp_auth_enable)
2632                        goto fall_through;
2633
2634                /* Save peer's HMAC list */
2635                asoc->peer.peer_hmacs = kmemdup(param.p,
2636                                            ntohs(param.p->length), gfp);
2637                if (!asoc->peer.peer_hmacs) {
2638                        retval = 0;
2639                        break;
2640                }
2641
2642                /* Set the default HMAC the peer requested*/
2643                sctp_auth_asoc_set_default_hmac(asoc, param.hmac_algo);
2644                break;
2645
2646        case SCTP_PARAM_CHUNKS:
2647                if (!sctp_auth_enable)
2648                        goto fall_through;
2649
2650                asoc->peer.peer_chunks = kmemdup(param.p,
2651                                            ntohs(param.p->length), gfp);
2652                if (!asoc->peer.peer_chunks)
2653                        retval = 0;
2654                break;
2655fall_through:
2656        default:
2657                /* Any unrecognized parameters should have been caught
2658                 * and handled by sctp_verify_param() which should be
2659                 * called prior to this routine.  Simply log the error
2660                 * here.
2661                 */
2662                SCTP_DEBUG_PRINTK("Ignoring param: %d for association %p.\n",
2663                                  ntohs(param.p->type), asoc);
2664                break;
2665        }
2666
2667        return retval;
2668}
2669
2670/* Select a new verification tag.  */
2671__u32 sctp_generate_tag(const struct sctp_endpoint *ep)
2672{
2673        /* I believe that this random number generator complies with RFC1750.
2674         * A tag of 0 is reserved for special cases (e.g. INIT).
2675         */
2676        __u32 x;
2677
2678        do {
2679                get_random_bytes(&x, sizeof(__u32));
2680        } while (x == 0);
2681
2682        return x;
2683}
2684
2685/* Select an initial TSN to send during startup.  */
2686__u32 sctp_generate_tsn(const struct sctp_endpoint *ep)
2687{
2688        __u32 retval;
2689
2690        get_random_bytes(&retval, sizeof(__u32));
2691        return retval;
2692}
2693
2694/*
2695 * ADDIP 3.1.1 Address Configuration Change Chunk (ASCONF)
2696 *      0                   1                   2                   3
2697 *      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
2698 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2699 *     | Type = 0xC1   |  Chunk Flags  |      Chunk Length             |
2700 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2701 *     |                       Serial Number                           |
2702 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2703 *     |                    Address Parameter                          |
2704 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2705 *     |                     ASCONF Parameter #1                       |
2706 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2707 *     \                                                               \
2708 *     /                             ....                              /
2709 *     \                                                               \
2710 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2711 *     |                     ASCONF Parameter #N                       |
2712 *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2713 *
2714 * Address Parameter and other parameter will not be wrapped in this function
2715 */
2716static struct sctp_chunk *sctp_make_asconf(struct sctp_association *asoc,
2717                                           union sctp_addr *addr,
2718                                           int vparam_len)
2719{
2720        sctp_addiphdr_t asconf;
2721        struct sctp_chunk *retval;
2722        int length = sizeof(asconf) + vparam_len;
2723        union sctp_addr_param addrparam;
2724        int addrlen;
2725        struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
2726
2727        addrlen = af->to_addr_param(addr, &addrparam);
2728        if (!addrlen)
2729                return NULL;
2730        length += addrlen;
2731
2732        /* Create the chunk.  */
2733        retval = sctp_make_chunk(asoc, SCTP_CID_ASCONF, 0, length);
2734        if (!retval)
2735                return NULL;
2736
2737        asconf.serial = htonl(asoc->addip_serial++);
2738
2739        retval->subh.addip_hdr =
2740                sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2741        retval->param_hdr.v =
2742                sctp_addto_chunk(retval, addrlen, &addrparam);
2743
2744        return retval;
2745}
2746
2747/* ADDIP
2748 * 3.2.1 Add IP Address
2749 *      0                   1                   2                   3
2750 *      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
2751 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2752 *     |        Type = 0xC001          |    Length = Variable          |
2753 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2754 *     |               ASCONF-Request Correlation ID                   |
2755 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2756 *     |                       Address Parameter                       |
2757 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2758 *
2759 * 3.2.2 Delete IP Address
2760 *      0                   1                   2                   3
2761 *      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
2762 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2763 *     |        Type = 0xC002          |    Length = Variable          |
2764 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2765 *     |               ASCONF-Request Correlation ID                   |
2766 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2767 *     |                       Address Parameter                       |
2768 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2769 *
2770 */
2771struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *asoc,
2772                                              union sctp_addr         *laddr,
2773                                              struct sockaddr         *addrs,
2774                                              int                     addrcnt,
2775                                              __be16                  flags)
2776{
2777        sctp_addip_param_t      param;
2778        struct sctp_chunk       *retval;
2779        union sctp_addr_param   addr_param;
2780        union sctp_addr         *addr;
2781        void                    *addr_buf;
2782        struct sctp_af          *af;
2783        int                     paramlen = sizeof(param);
2784        int                     addr_param_len = 0;
2785        int                     totallen = 0;
2786        int                     i;
2787        int                     del_pickup = 0;
2788
2789        /* Get total length of all the address parameters. */
2790        addr_buf = addrs;
2791        for (i = 0; i < addrcnt; i++) {
2792                addr = addr_buf;
2793                af = sctp_get_af_specific(addr->v4.sin_family);
2794                addr_param_len = af->to_addr_param(addr, &addr_param);
2795
2796                totallen += paramlen;
2797                totallen += addr_param_len;
2798
2799                addr_buf += af->sockaddr_len;
2800                if (asoc->asconf_addr_del_pending && !del_pickup) {
2801                        /* reuse the parameter length from the same scope one */
2802                        totallen += paramlen;
2803                        totallen += addr_param_len;
2804                        del_pickup = 1;
2805                        SCTP_DEBUG_PRINTK("mkasconf_update_ip: picked same-scope del_pending addr, totallen for all addresses is %d\n", totallen);
2806                }
2807        }
2808
2809        /* Create an asconf chunk with the required length. */
2810        retval = sctp_make_asconf(asoc, laddr, totallen);
2811        if (!retval)
2812                return NULL;
2813
2814        /* Add the address parameters to the asconf chunk. */
2815        addr_buf = addrs;
2816        for (i = 0; i < addrcnt; i++) {
2817                addr = addr_buf;
2818                af = sctp_get_af_specific(addr->v4.sin_family);
2819                addr_param_len = af->to_addr_param(addr, &addr_param);
2820                param.param_hdr.type = flags;
2821                param.param_hdr.length = htons(paramlen + addr_param_len);
2822                param.crr_id = i;
2823
2824                sctp_addto_chunk(retval, paramlen, &param);
2825                sctp_addto_chunk(retval, addr_param_len, &addr_param);
2826
2827                addr_buf += af->sockaddr_len;
2828        }
2829        if (flags == SCTP_PARAM_ADD_IP && del_pickup) {
2830                addr = asoc->asconf_addr_del_pending;
2831                af = sctp_get_af_specific(addr->v4.sin_family);
2832                addr_param_len = af->to_addr_param(addr, &addr_param);
2833                param.param_hdr.type = SCTP_PARAM_DEL_IP;
2834                param.param_hdr.length = htons(paramlen + addr_param_len);
2835                param.crr_id = i;
2836
2837                sctp_addto_chunk(retval, paramlen, &param);
2838                sctp_addto_chunk(retval, addr_param_len, &addr_param);
2839        }
2840        return retval;
2841}
2842
2843/* ADDIP
2844 * 3.2.4 Set Primary IP Address
2845 *      0                   1                   2                   3
2846 *      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
2847 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2848 *     |        Type =0xC004           |    Length = Variable          |
2849 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2850 *     |               ASCONF-Request Correlation ID                   |
2851 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2852 *     |                       Address Parameter                       |
2853 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2854 *
2855 * Create an ASCONF chunk with Set Primary IP address parameter.
2856 */
2857struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
2858                                             union sctp_addr *addr)
2859{
2860        sctp_addip_param_t      param;
2861        struct sctp_chunk       *retval;
2862        int                     len = sizeof(param);
2863        union sctp_addr_param   addrparam;
2864        int                     addrlen;
2865        struct sctp_af          *af = sctp_get_af_specific(addr->v4.sin_family);
2866
2867        addrlen = af->to_addr_param(addr, &addrparam);
2868        if (!addrlen)
2869                return NULL;
2870        len += addrlen;
2871
2872        /* Create the chunk and make asconf header. */
2873        retval = sctp_make_asconf(asoc, addr, len);
2874        if (!retval)
2875                return NULL;
2876
2877        param.param_hdr.type = SCTP_PARAM_SET_PRIMARY;
2878        param.param_hdr.length = htons(len);
2879        param.crr_id = 0;
2880
2881        sctp_addto_chunk(retval, sizeof(param), &param);
2882        sctp_addto_chunk(retval, addrlen, &addrparam);
2883
2884        return retval;
2885}
2886
2887/* ADDIP 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
2888 *      0                   1                   2                   3
2889 *      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
2890 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2891 *     | Type = 0x80   |  Chunk Flags  |      Chunk Length             |
2892 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2893 *     |                       Serial Number                           |
2894 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2895 *     |                 ASCONF Parameter Response#1                   |
2896 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2897 *     \                                                               \
2898 *     /                             ....                              /
2899 *     \                                                               \
2900 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2901 *     |                 ASCONF Parameter Response#N                   |
2902 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2903 *
2904 * Create an ASCONF_ACK chunk with enough space for the parameter responses.
2905 */
2906static struct sctp_chunk *sctp_make_asconf_ack(const struct sctp_association *asoc,
2907                                               __u32 serial, int vparam_len)
2908{
2909        sctp_addiphdr_t         asconf;
2910        struct sctp_chunk       *retval;
2911        int                     length = sizeof(asconf) + vparam_len;
2912
2913        /* Create the chunk.  */
2914        retval = sctp_make_chunk(asoc, SCTP_CID_ASCONF_ACK, 0, length);
2915        if (!retval)
2916                return NULL;
2917
2918        asconf.serial = htonl(serial);
2919
2920        retval->subh.addip_hdr =
2921                sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2922
2923        return retval;
2924}
2925
2926/* Add response parameters to an ASCONF_ACK chunk. */
2927static void sctp_add_asconf_response(struct sctp_chunk *chunk, __be32 crr_id,
2928                              __be16 err_code, sctp_addip_param_t *asconf_param)
2929{
2930        sctp_addip_param_t      ack_param;
2931        sctp_errhdr_t           err_param;
2932        int                     asconf_param_len = 0;
2933        int                     err_param_len = 0;
2934        __be16                  response_type;
2935
2936        if (SCTP_ERROR_NO_ERROR == err_code) {
2937                response_type = SCTP_PARAM_SUCCESS_REPORT;
2938        } else {
2939                response_type = SCTP_PARAM_ERR_CAUSE;
2940                err_param_len = sizeof(err_param);
2941                if (asconf_param)
2942                        asconf_param_len =
2943                                 ntohs(asconf_param->param_hdr.length);
2944        }
2945
2946        /* Add Success Indication or Error Cause Indication parameter. */
2947        ack_param.param_hdr.type = response_type;
2948        ack_param.param_hdr.length = htons(sizeof(ack_param) +
2949                                           err_param_len +
2950                                           asconf_param_len);
2951        ack_param.crr_id = crr_id;
2952        sctp_addto_chunk(chunk, sizeof(ack_param), &ack_param);
2953
2954        if (SCTP_ERROR_NO_ERROR == err_code)
2955                return;
2956
2957        /* Add Error Cause parameter. */
2958        err_param.cause = err_code;
2959        err_param.length = htons(err_param_len + asconf_param_len);
2960        sctp_addto_chunk(chunk, err_param_len, &err_param);
2961
2962        /* Add the failed TLV copied from ASCONF chunk. */
2963        if (asconf_param)
2964                sctp_addto_chunk(chunk, asconf_param_len, asconf_param);
2965}
2966
2967/* Process a asconf parameter. */
2968static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
2969                                       struct sctp_chunk *asconf,
2970                                       sctp_addip_param_t *asconf_param)
2971{
2972        struct sctp_transport *peer;
2973        struct sctp_af *af;
2974        union sctp_addr addr;
2975        union sctp_addr_param *addr_param;
2976
2977        addr_param = (void *)asconf_param + sizeof(sctp_addip_param_t);
2978
2979        if (asconf_param->param_hdr.type != SCTP_PARAM_ADD_IP &&
2980            asconf_param->param_hdr.type != SCTP_PARAM_DEL_IP &&
2981            asconf_param->param_hdr.type != SCTP_PARAM_SET_PRIMARY)
2982                return SCTP_ERROR_UNKNOWN_PARAM;
2983
2984        switch (addr_param->p.type) {
2985        case SCTP_PARAM_IPV6_ADDRESS:
2986                if (!asoc->peer.ipv6_address)
2987                        return SCTP_ERROR_DNS_FAILED;
2988                break;
2989        case SCTP_PARAM_IPV4_ADDRESS:
2990                if (!asoc->peer.ipv4_address)
2991                        return SCTP_ERROR_DNS_FAILED;
2992                break;
2993        default:
2994                return SCTP_ERROR_DNS_FAILED;
2995        }
2996
2997        af = sctp_get_af_specific(param_type2af(addr_param->p.type));
2998        if (unlikely(!af))
2999                return SCTP_ERROR_DNS_FAILED;
3000
3001        af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);
3002
3003        /* ADDIP 4.2.1  This parameter MUST NOT contain a broadcast
3004         * or multicast address.
3005         * (note: wildcard is permitted and requires special handling so
3006         *  make sure we check for that)
3007         */
3008        if (!af->is_any(&addr) && !af->addr_valid(&addr, NULL, asconf->skb))
3009                return SCTP_ERROR_DNS_FAILED;
3010
3011        switch (asconf_param->param_hdr.type) {
3012        case SCTP_PARAM_ADD_IP:
3013                /* Section 4.2.1:
3014                 * If the address 0.0.0.0 or ::0 is provided, the source
3015                 * address of the packet MUST be added.
3016                 */
3017                if (af->is_any(&addr))
3018                        memcpy(&addr, &asconf->source, sizeof(addr));
3019
3020                /* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
3021                 * request and does not have the local resources to add this
3022                 * new address to the association, it MUST return an Error
3023                 * Cause TLV set to the new error code 'Operation Refused
3024                 * Due to Resource Shortage'.
3025                 */
3026
3027                peer = sctp_assoc_add_peer(asoc, &addr, GFP_ATOMIC, SCTP_UNCONFIRMED);
3028                if (!peer)
3029                        return SCTP_ERROR_RSRC_LOW;
3030
3031                /* Start the heartbeat timer. */
3032                if (!mod_timer(&peer->hb_timer, sctp_transport_timeout(peer)))
3033                        sctp_transport_hold(peer);
3034                asoc->new_transport = peer;
3035                break;
3036        case SCTP_PARAM_DEL_IP:
3037                /* ADDIP 4.3 D7) If a request is received to delete the
3038                 * last remaining IP address of a peer endpoint, the receiver
3039                 * MUST send an Error Cause TLV with the error cause set to the
3040                 * new error code 'Request to Delete Last Remaining IP Address'.
3041                 */
3042                if (asoc->peer.transport_count == 1)
3043                        return SCTP_ERROR_DEL_LAST_IP;
3044
3045                /* ADDIP 4.3 D8) If a request is received to delete an IP
3046                 * address which is also the source address of the IP packet
3047                 * which contained the ASCONF chunk, the receiver MUST reject
3048                 * this request. To reject the request the receiver MUST send
3049                 * an Error Cause TLV set to the new error code 'Request to
3050                 * Delete Source IP Address'
3051                 */
3052                if (sctp_cmp_addr_exact(&asconf->source, &addr))
3053                        return SCTP_ERROR_DEL_SRC_IP;
3054
3055                /* Section 4.2.2
3056                 * If the address 0.0.0.0 or ::0 is provided, all
3057                 * addresses of the peer except the source address of the
3058                 * packet MUST be deleted.
3059                 */
3060                if (af->is_any(&addr)) {
3061                        sctp_assoc_set_primary(asoc, asconf->transport);
3062                        sctp_assoc_del_nonprimary_peers(asoc,
3063                                                        asconf->transport);
3064                } else
3065                        sctp_assoc_del_peer(asoc, &addr);
3066                break;
3067        case SCTP_PARAM_SET_PRIMARY:
3068                /* ADDIP Section 4.2.4
3069                 * If the address 0.0.0.0 or ::0 is provided, the receiver
3070                 * MAY mark the source address of the packet as its
3071                 * primary.
3072                 */
3073                if (af->is_any(&addr))
3074                        memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));
3075
3076                peer = sctp_assoc_lookup_paddr(asoc, &addr);
3077                if (!peer)
3078                        return SCTP_ERROR_DNS_FAILED;
3079
3080                sctp_assoc_set_primary(asoc, peer);
3081                break;
3082        }
3083
3084        return SCTP_ERROR_NO_ERROR;
3085}
3086
3087/* Verify the ASCONF packet before we process it.  */
3088int sctp_verify_asconf(const struct sctp_association *asoc,
3089                       struct sctp_paramhdr *param_hdr, void *chunk_end,
3090                       struct sctp_paramhdr **errp) {
3091        sctp_addip_param_t *asconf_param;
3092        union sctp_params param;
3093        int length, plen;
3094
3095        param.v = (sctp_paramhdr_t *) param_hdr;
3096        while (param.v <= chunk_end - sizeof(sctp_paramhdr_t)) {
3097                length = ntohs(param.p->length);
3098                *errp = param.p;
3099
3100                if (param.v > chunk_end - length ||
3101                    length < sizeof(sctp_paramhdr_t))
3102                        return 0;
3103
3104                switch (param.p->type) {
3105                case SCTP_PARAM_ADD_IP:
3106                case SCTP_PARAM_DEL_IP:
3107                case SCTP_PARAM_SET_PRIMARY:
3108                        asconf_param = (sctp_addip_param_t *)param.v;
3109                        plen = ntohs(asconf_param->param_hdr.length);
3110                        if (plen < sizeof(sctp_addip_param_t) +
3111                            sizeof(sctp_paramhdr_t))
3112                                return 0;
3113                        break;
3114                case SCTP_PARAM_SUCCESS_REPORT:
3115                case SCTP_PARAM_ADAPTATION_LAYER_IND:
3116                        if (length != sizeof(sctp_addip_param_t))
3117                                return 0;
3118
3119                        break;
3120                default:
3121                        break;
3122                }
3123
3124                param.v += WORD_ROUND(length);
3125        }
3126
3127        if (param.v != chunk_end)
3128                return 0;
3129
3130        return 1;
3131}
3132
3133/* Process an incoming ASCONF chunk with the next expected serial no. and
3134 * return an ASCONF_ACK chunk to be sent in response.
3135 */
3136struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
3137                                       struct sctp_chunk *asconf)
3138{
3139        sctp_addiphdr_t         *hdr;
3140        union sctp_addr_param   *addr_param;
3141        sctp_addip_param_t      *asconf_param;
3142        struct sctp_chunk       *asconf_ack;
3143
3144        __be16  err_code;
3145        int     length = 0;
3146        int     chunk_len;
3147        __u32   serial;
3148        int     all_param_pass = 1;
3149
3150        chunk_len = ntohs(asconf->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
3151        hdr = (sctp_addiphdr_t *)asconf->skb->data;
3152        serial = ntohl(hdr->serial);
3153
3154        /* Skip the addiphdr and store a pointer to address parameter.  */
3155        length = sizeof(sctp_addiphdr_t);
3156        addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3157        chunk_len -= length;
3158
3159        /* Skip the address parameter and store a pointer to the first
3160         * asconf parameter.
3161         */
3162        length = ntohs(addr_param->p.length);
3163        asconf_param = (void *)addr_param + length;
3164        chunk_len -= length;
3165
3166        /* create an ASCONF_ACK chunk.
3167         * Based on the definitions of parameters, we know that the size of
3168         * ASCONF_ACK parameters are less than or equal to the fourfold of ASCONF
3169         * parameters.
3170         */
3171        asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 4);
3172        if (!asconf_ack)
3173                goto done;
3174
3175        /* Process the TLVs contained within the ASCONF chunk. */
3176        while (chunk_len > 0) {
3177                err_code = sctp_process_asconf_param(asoc, asconf,
3178                                                     asconf_param);
3179                /* ADDIP 4.1 A7)
3180                 * If an error response is received for a TLV parameter,
3181                 * all TLVs with no response before the failed TLV are
3182                 * considered successful if not reported.  All TLVs after
3183                 * the failed response are considered unsuccessful unless
3184                 * a specific success indication is present for the parameter.
3185                 */
3186                if (SCTP_ERROR_NO_ERROR != err_code)
3187                        all_param_pass = 0;
3188
3189                if (!all_param_pass)
3190                        sctp_add_asconf_response(asconf_ack,
3191                                                 asconf_param->crr_id, err_code,
3192                                                 asconf_param);
3193
3194                /* ADDIP 4.3 D11) When an endpoint receiving an ASCONF to add
3195                 * an IP address sends an 'Out of Resource' in its response, it
3196                 * MUST also fail any subsequent add or delete requests bundled
3197                 * in the ASCONF.
3198                 */
3199                if (SCTP_ERROR_RSRC_LOW == err_code)
3200                        goto done;
3201
3202                /* Move to the next ASCONF param. */
3203                length = ntohs(asconf_param->param_hdr.length);
3204                asconf_param = (void *)asconf_param + length;
3205                chunk_len -= length;
3206        }
3207
3208done:
3209        asoc->peer.addip_serial++;
3210
3211        /* If we are sending a new ASCONF_ACK hold a reference to it in assoc
3212         * after freeing the reference to old asconf ack if any.
3213         */
3214        if (asconf_ack) {
3215                sctp_chunk_hold(asconf_ack);
3216                list_add_tail(&asconf_ack->transmitted_list,
3217                              &asoc->asconf_ack_list);
3218        }
3219
3220        return asconf_ack;
3221}
3222
3223/* Process a asconf parameter that is successfully acked. */
3224static void sctp_asconf_param_success(struct sctp_association *asoc,
3225                                     sctp_addip_param_t *asconf_param)
3226{
3227        struct sctp_af *af;
3228        union sctp_addr addr;
3229        struct sctp_bind_addr *bp = &asoc->base.bind_addr;
3230        union sctp_addr_param *addr_param;
3231        struct sctp_transport *transport;
3232        struct sctp_sockaddr_entry *saddr;
3233
3234        addr_param = (void *)asconf_param + sizeof(sctp_addip_param_t);
3235
3236        /* We have checked the packet before, so we do not check again. */
3237        af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3238        af->from_addr_param(&addr, addr_param, htons(bp->port), 0);
3239
3240        switch (asconf_param->param_hdr.type) {
3241        case SCTP_PARAM_ADD_IP:
3242                /* This is always done in BH context with a socket lock
3243                 * held, so the list can not change.
3244                 */
3245                local_bh_disable();
3246                list_for_each_entry(saddr, &bp->address_list, list) {
3247                        if (sctp_cmp_addr_exact(&saddr->a, &addr))
3248                                saddr->state = SCTP_ADDR_SRC;
3249                }
3250                local_bh_enable();
3251                list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3252                                transports) {
3253                        dst_release(transport->dst);
3254                        transport->dst = NULL;
3255                }
3256                break;
3257        case SCTP_PARAM_DEL_IP:
3258                local_bh_disable();
3259                sctp_del_bind_addr(bp, &addr);
3260                if (asoc->asconf_addr_del_pending != NULL &&
3261                    sctp_cmp_addr_exact(asoc->asconf_addr_del_pending, &addr)) {
3262                        kfree(asoc->asconf_addr_del_pending);
3263                        asoc->asconf_addr_del_pending = NULL;
3264                }
3265                local_bh_enable();
3266                list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3267                                transports) {
3268                        dst_release(transport->dst);
3269                        transport->dst = NULL;
3270                }
3271                break;
3272        default:
3273                break;
3274        }
3275}
3276
3277/* Get the corresponding ASCONF response error code from the ASCONF_ACK chunk
3278 * for the given asconf parameter.  If there is no response for this parameter,
3279 * return the error code based on the third argument 'no_err'.
3280 * ADDIP 4.1
3281 * A7) If an error response is received for a TLV parameter, all TLVs with no
3282 * response before the failed TLV are considered successful if not reported.
3283 * All TLVs after the failed response are considered unsuccessful unless a
3284 * specific success indication is present for the parameter.
3285 */
3286static __be16 sctp_get_asconf_response(struct sctp_chunk *asconf_ack,
3287                                      sctp_addip_param_t *asconf_param,
3288                                      int no_err)
3289{
3290        sctp_addip_param_t      *asconf_ack_param;
3291        sctp_errhdr_t           *err_param;
3292        int                     length;
3293        int                     asconf_ack_len;
3294        __be16                  err_code;
3295
3296        if (no_err)
3297                err_code = SCTP_ERROR_NO_ERROR;
3298        else
3299                err_code = SCTP_ERROR_REQ_REFUSED;
3300
3301        asconf_ack_len = ntohs(asconf_ack->chunk_hdr->length) -
3302                             sizeof(sctp_chunkhdr_t);
3303
3304        /* Skip the addiphdr from the asconf_ack chunk and store a pointer to
3305         * the first asconf_ack parameter.
3306         */
3307        length = sizeof(sctp_addiphdr_t);
3308        asconf_ack_param = (sctp_addip_param_t *)(asconf_ack->skb->data +
3309                                                  length);
3310        asconf_ack_len -= length;
3311
3312        while (asconf_ack_len > 0) {
3313                if (asconf_ack_param->crr_id == asconf_param->crr_id) {
3314                        switch(asconf_ack_param->param_hdr.type) {
3315                        case SCTP_PARAM_SUCCESS_REPORT:
3316                                return SCTP_ERROR_NO_ERROR;
3317                        case SCTP_PARAM_ERR_CAUSE:
3318                                length = sizeof(sctp_addip_param_t);
3319                                err_param = (void *)asconf_ack_param + length;
3320                                asconf_ack_len -= length;
3321                                if (asconf_ack_len > 0)
3322                                        return err_param->cause;
3323                                else
3324                                        return SCTP_ERROR_INV_PARAM;
3325                                break;
3326                        default:
3327                                return SCTP_ERROR_INV_PARAM;
3328                        }
3329                }
3330
3331                length = ntohs(asconf_ack_param->param_hdr.length);
3332                asconf_ack_param = (void *)asconf_ack_param + length;
3333                asconf_ack_len -= length;
3334        }
3335
3336        return err_code;
3337}
3338
3339/* Process an incoming ASCONF_ACK chunk against the cached last ASCONF chunk. */
3340int sctp_process_asconf_ack(struct sctp_association *asoc,
3341                            struct sctp_chunk *asconf_ack)
3342{
3343        struct sctp_chunk       *asconf = asoc->addip_last_asconf;
3344        union sctp_addr_param   *addr_param;
3345        sctp_addip_param_t      *asconf_param;
3346        int     length = 0;
3347        int     asconf_len = asconf->skb->len;
3348        int     all_param_pass = 0;
3349        int     no_err = 1;
3350        int     retval = 0;
3351        __be16  err_code = SCTP_ERROR_NO_ERROR;
3352
3353        /* Skip the chunkhdr and addiphdr from the last asconf sent and store
3354         * a pointer to address parameter.
3355         */
3356        length = sizeof(sctp_addip_chunk_t);
3357        addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3358        asconf_len -= length;
3359
3360        /* Skip the address parameter in the last asconf sent and store a
3361         * pointer to the first asconf parameter.
3362         */
3363        length = ntohs(addr_param->p.length);
3364        asconf_param = (void *)addr_param + length;
3365        asconf_len -= length;
3366
3367        /* ADDIP 4.1
3368         * A8) If there is no response(s) to specific TLV parameter(s), and no
3369         * failures are indicated, then all request(s) are considered
3370         * successful.
3371         */
3372        if (asconf_ack->skb->len == sizeof(sctp_addiphdr_t))
3373                all_param_pass = 1;
3374
3375        /* Process the TLVs contained in the last sent ASCONF chunk. */
3376        while (asconf_len > 0) {
3377                if (all_param_pass)
3378                        err_code = SCTP_ERROR_NO_ERROR;
3379                else {
3380                        err_code = sctp_get_asconf_response(asconf_ack,
3381                                                            asconf_param,
3382                                                            no_err);
3383                        if (no_err && (SCTP_ERROR_NO_ERROR != err_code))
3384                                no_err = 0;
3385                }
3386
3387                switch (err_code) {
3388                case SCTP_ERROR_NO_ERROR:
3389                        sctp_asconf_param_success(asoc, asconf_param);
3390                        break;
3391
3392                case SCTP_ERROR_RSRC_LOW:
3393                        retval = 1;
3394                        break;
3395
3396                case SCTP_ERROR_UNKNOWN_PARAM:
3397                        /* Disable sending this type of asconf parameter in
3398                         * future.
3399                         */
3400                        asoc->peer.addip_disabled_mask |=
3401                                asconf_param->param_hdr.type;
3402                        break;
3403
3404                case SCTP_ERROR_REQ_REFUSED:
3405                case SCTP_ERROR_DEL_LAST_IP:
3406                case SCTP_ERROR_DEL_SRC_IP:
3407                default:
3408                         break;
3409                }
3410
3411                /* Skip the processed asconf parameter and move to the next
3412                 * one.
3413                 */
3414                length = ntohs(asconf_param->param_hdr.length);
3415                asconf_param = (void *)asconf_param + length;
3416                asconf_len -= length;
3417        }
3418
3419        if (no_err && asoc->src_out_of_asoc_ok) {
3420                asoc->src_out_of_asoc_ok = 0;
3421                sctp_transport_immediate_rtx(asoc->peer.primary_path);
3422        }
3423
3424        /* Free the cached last sent asconf chunk. */
3425        list_del_init(&asconf->transmitted_list);
3426        sctp_chunk_free(asconf);
3427        asoc->addip_last_asconf = NULL;
3428
3429        return retval;
3430}
3431
3432/* Make a FWD TSN chunk. */
3433struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
3434                                    __u32 new_cum_tsn, size_t nstreams,
3435                                    struct sctp_fwdtsn_skip *skiplist)
3436{
3437        struct sctp_chunk *retval = NULL;
3438        struct sctp_fwdtsn_hdr ftsn_hdr;
3439        struct sctp_fwdtsn_skip skip;
3440        size_t hint;
3441        int i;
3442
3443        hint = (nstreams + 1) * sizeof(__u32);
3444
3445        retval = sctp_make_chunk(asoc, SCTP_CID_FWD_TSN, 0, hint);
3446
3447        if (!retval)
3448                return NULL;
3449
3450        ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
3451        retval->subh.fwdtsn_hdr =
3452                sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
3453
3454        for (i = 0; i < nstreams; i++) {
3455                skip.stream = skiplist[i].stream;
3456                skip.ssn = skiplist[i].ssn;
3457                sctp_addto_chunk(retval, sizeof(skip), &skip);
3458        }
3459
3460        return retval;
3461}
3462
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