linux/net/sctp/sm_statefuns.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 * Copyright (c) 2002      Nokia Corp.
   7 *
   8 * This is part of the SCTP Linux Kernel Implementation.
   9 *
  10 * These are the state functions for the state machine.
  11 *
  12 * This SCTP implementation is free software;
  13 * you can redistribute it and/or modify it under the terms of
  14 * the GNU General Public License as published by
  15 * the Free Software Foundation; either version 2, or (at your option)
  16 * any later version.
  17 *
  18 * This SCTP implementation is distributed in the hope that it
  19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  20 *                 ************************
  21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  22 * See the GNU General Public License for more details.
  23 *
  24 * You should have received a copy of the GNU General Public License
  25 * along with GNU CC; see the file COPYING.  If not, write to
  26 * the Free Software Foundation, 59 Temple Place - Suite 330,
  27 * Boston, MA 02111-1307, USA.
  28 *
  29 * Please send any bug reports or fixes you make to the
  30 * email address(es):
  31 *    lksctp developers <lksctp-developers@lists.sourceforge.net>
  32 *
  33 * Or submit a bug report through the following website:
  34 *    http://www.sf.net/projects/lksctp
  35 *
  36 * Written or modified by:
  37 *    La Monte H.P. Yarroll <piggy@acm.org>
  38 *    Karl Knutson          <karl@athena.chicago.il.us>
  39 *    Mathew Kotowsky       <kotowsky@sctp.org>
  40 *    Sridhar Samudrala     <samudrala@us.ibm.com>
  41 *    Jon Grimm             <jgrimm@us.ibm.com>
  42 *    Hui Huang             <hui.huang@nokia.com>
  43 *    Dajiang Zhang         <dajiang.zhang@nokia.com>
  44 *    Daisy Chang           <daisyc@us.ibm.com>
  45 *    Ardelle Fan           <ardelle.fan@intel.com>
  46 *    Ryan Layer            <rmlayer@us.ibm.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/slab.h>
  62#include <net/sock.h>
  63#include <net/inet_ecn.h>
  64#include <linux/skbuff.h>
  65#include <net/sctp/sctp.h>
  66#include <net/sctp/sm.h>
  67#include <net/sctp/structs.h>
  68
  69static struct sctp_packet *sctp_abort_pkt_new(struct net *net,
  70                                  const struct sctp_endpoint *ep,
  71                                  const struct sctp_association *asoc,
  72                                  struct sctp_chunk *chunk,
  73                                  const void *payload,
  74                                  size_t paylen);
  75static int sctp_eat_data(const struct sctp_association *asoc,
  76                         struct sctp_chunk *chunk,
  77                         sctp_cmd_seq_t *commands);
  78static struct sctp_packet *sctp_ootb_pkt_new(struct net *net,
  79                                             const struct sctp_association *asoc,
  80                                             const struct sctp_chunk *chunk);
  81static void sctp_send_stale_cookie_err(struct net *net,
  82                                       const struct sctp_endpoint *ep,
  83                                       const struct sctp_association *asoc,
  84                                       const struct sctp_chunk *chunk,
  85                                       sctp_cmd_seq_t *commands,
  86                                       struct sctp_chunk *err_chunk);
  87static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net,
  88                                                 const struct sctp_endpoint *ep,
  89                                                 const struct sctp_association *asoc,
  90                                                 const sctp_subtype_t type,
  91                                                 void *arg,
  92                                                 sctp_cmd_seq_t *commands);
  93static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net,
  94                                             const struct sctp_endpoint *ep,
  95                                             const struct sctp_association *asoc,
  96                                             const sctp_subtype_t type,
  97                                             void *arg,
  98                                             sctp_cmd_seq_t *commands);
  99static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net,
 100                                        const struct sctp_endpoint *ep,
 101                                        const struct sctp_association *asoc,
 102                                        const sctp_subtype_t type,
 103                                        void *arg,
 104                                        sctp_cmd_seq_t *commands);
 105static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);
 106
 107static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net,
 108                                           sctp_cmd_seq_t *commands,
 109                                           __be16 error, int sk_err,
 110                                           const struct sctp_association *asoc,
 111                                           struct sctp_transport *transport);
 112
 113static sctp_disposition_t sctp_sf_abort_violation(
 114                                     struct net *net,
 115                                     const struct sctp_endpoint *ep,
 116                                     const struct sctp_association *asoc,
 117                                     void *arg,
 118                                     sctp_cmd_seq_t *commands,
 119                                     const __u8 *payload,
 120                                     const size_t paylen);
 121
 122static sctp_disposition_t sctp_sf_violation_chunklen(
 123                                     struct net *net,
 124                                     const struct sctp_endpoint *ep,
 125                                     const struct sctp_association *asoc,
 126                                     const sctp_subtype_t type,
 127                                     void *arg,
 128                                     sctp_cmd_seq_t *commands);
 129
 130static sctp_disposition_t sctp_sf_violation_paramlen(
 131                                     struct net *net,
 132                                     const struct sctp_endpoint *ep,
 133                                     const struct sctp_association *asoc,
 134                                     const sctp_subtype_t type,
 135                                     void *arg, void *ext,
 136                                     sctp_cmd_seq_t *commands);
 137
 138static sctp_disposition_t sctp_sf_violation_ctsn(
 139                                     struct net *net,
 140                                     const struct sctp_endpoint *ep,
 141                                     const struct sctp_association *asoc,
 142                                     const sctp_subtype_t type,
 143                                     void *arg,
 144                                     sctp_cmd_seq_t *commands);
 145
 146static sctp_disposition_t sctp_sf_violation_chunk(
 147                                     struct net *net,
 148                                     const struct sctp_endpoint *ep,
 149                                     const struct sctp_association *asoc,
 150                                     const sctp_subtype_t type,
 151                                     void *arg,
 152                                     sctp_cmd_seq_t *commands);
 153
 154static sctp_ierror_t sctp_sf_authenticate(struct net *net,
 155                                    const struct sctp_endpoint *ep,
 156                                    const struct sctp_association *asoc,
 157                                    const sctp_subtype_t type,
 158                                    struct sctp_chunk *chunk);
 159
 160static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net,
 161                                        const struct sctp_endpoint *ep,
 162                                        const struct sctp_association *asoc,
 163                                        const sctp_subtype_t type,
 164                                        void *arg,
 165                                        sctp_cmd_seq_t *commands);
 166
 167/* Small helper function that checks if the chunk length
 168 * is of the appropriate length.  The 'required_length' argument
 169 * is set to be the size of a specific chunk we are testing.
 170 * Return Values:  1 = Valid length
 171 *                 0 = Invalid length
 172 *
 173 */
 174static inline int
 175sctp_chunk_length_valid(struct sctp_chunk *chunk,
 176                           __u16 required_length)
 177{
 178        __u16 chunk_length = ntohs(chunk->chunk_hdr->length);
 179
 180        if (unlikely(chunk_length < required_length))
 181                return 0;
 182
 183        return 1;
 184}
 185
 186/**********************************************************
 187 * These are the state functions for handling chunk events.
 188 **********************************************************/
 189
 190/*
 191 * Process the final SHUTDOWN COMPLETE.
 192 *
 193 * Section: 4 (C) (diagram), 9.2
 194 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
 195 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
 196 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
 197 * should stop the T2-shutdown timer and remove all knowledge of the
 198 * association (and thus the association enters the CLOSED state).
 199 *
 200 * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
 201 * C) Rules for packet carrying SHUTDOWN COMPLETE:
 202 * ...
 203 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
 204 *   if the Verification Tag field of the packet matches its own tag and
 205 *   the T bit is not set
 206 *   OR
 207 *   it is set to its peer's tag and the T bit is set in the Chunk
 208 *   Flags.
 209 *   Otherwise, the receiver MUST silently discard the packet
 210 *   and take no further action.  An endpoint MUST ignore the
 211 *   SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
 212 *
 213 * Inputs
 214 * (endpoint, asoc, chunk)
 215 *
 216 * Outputs
 217 * (asoc, reply_msg, msg_up, timers, counters)
 218 *
 219 * The return value is the disposition of the chunk.
 220 */
 221sctp_disposition_t sctp_sf_do_4_C(struct net *net,
 222                                  const struct sctp_endpoint *ep,
 223                                  const struct sctp_association *asoc,
 224                                  const sctp_subtype_t type,
 225                                  void *arg,
 226                                  sctp_cmd_seq_t *commands)
 227{
 228        struct sctp_chunk *chunk = arg;
 229        struct sctp_ulpevent *ev;
 230
 231        if (!sctp_vtag_verify_either(chunk, asoc))
 232                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 233
 234        /* RFC 2960 6.10 Bundling
 235         *
 236         * An endpoint MUST NOT bundle INIT, INIT ACK or
 237         * SHUTDOWN COMPLETE with any other chunks.
 238         */
 239        if (!chunk->singleton)
 240                return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
 241
 242        /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */
 243        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
 244                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
 245                                                  commands);
 246
 247        /* RFC 2960 10.2 SCTP-to-ULP
 248         *
 249         * H) SHUTDOWN COMPLETE notification
 250         *
 251         * When SCTP completes the shutdown procedures (section 9.2) this
 252         * notification is passed to the upper layer.
 253         */
 254        ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
 255                                             0, 0, 0, NULL, GFP_ATOMIC);
 256        if (ev)
 257                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 258                                SCTP_ULPEVENT(ev));
 259
 260        /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
 261         * will verify that it is in SHUTDOWN-ACK-SENT state, if it is
 262         * not the chunk should be discarded. If the endpoint is in
 263         * the SHUTDOWN-ACK-SENT state the endpoint should stop the
 264         * T2-shutdown timer and remove all knowledge of the
 265         * association (and thus the association enters the CLOSED
 266         * state).
 267         */
 268        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 269                        SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
 270
 271        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 272                        SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
 273
 274        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 275                        SCTP_STATE(SCTP_STATE_CLOSED));
 276
 277        SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
 278        SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
 279
 280        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 281
 282        return SCTP_DISPOSITION_DELETE_TCB;
 283}
 284
 285/*
 286 * Respond to a normal INIT chunk.
 287 * We are the side that is being asked for an association.
 288 *
 289 * Section: 5.1 Normal Establishment of an Association, B
 290 * B) "Z" shall respond immediately with an INIT ACK chunk.  The
 291 *    destination IP address of the INIT ACK MUST be set to the source
 292 *    IP address of the INIT to which this INIT ACK is responding.  In
 293 *    the response, besides filling in other parameters, "Z" must set the
 294 *    Verification Tag field to Tag_A, and also provide its own
 295 *    Verification Tag (Tag_Z) in the Initiate Tag field.
 296 *
 297 * Verification Tag: Must be 0.
 298 *
 299 * Inputs
 300 * (endpoint, asoc, chunk)
 301 *
 302 * Outputs
 303 * (asoc, reply_msg, msg_up, timers, counters)
 304 *
 305 * The return value is the disposition of the chunk.
 306 */
 307sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net,
 308                                        const struct sctp_endpoint *ep,
 309                                        const struct sctp_association *asoc,
 310                                        const sctp_subtype_t type,
 311                                        void *arg,
 312                                        sctp_cmd_seq_t *commands)
 313{
 314        struct sctp_chunk *chunk = arg;
 315        struct sctp_chunk *repl;
 316        struct sctp_association *new_asoc;
 317        struct sctp_chunk *err_chunk;
 318        struct sctp_packet *packet;
 319        sctp_unrecognized_param_t *unk_param;
 320        int len;
 321
 322        /* 6.10 Bundling
 323         * An endpoint MUST NOT bundle INIT, INIT ACK or
 324         * SHUTDOWN COMPLETE with any other chunks.
 325         *
 326         * IG Section 2.11.2
 327         * Furthermore, we require that the receiver of an INIT chunk MUST
 328         * enforce these rules by silently discarding an arriving packet
 329         * with an INIT chunk that is bundled with other chunks.
 330         */
 331        if (!chunk->singleton)
 332                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 333
 334        /* If the packet is an OOTB packet which is temporarily on the
 335         * control endpoint, respond with an ABORT.
 336         */
 337        if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
 338                SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
 339                return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
 340        }
 341
 342        /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
 343         * Tag.
 344         */
 345        if (chunk->sctp_hdr->vtag != 0)
 346                return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
 347
 348        /* Make sure that the INIT chunk has a valid length.
 349         * Normally, this would cause an ABORT with a Protocol Violation
 350         * error, but since we don't have an association, we'll
 351         * just discard the packet.
 352         */
 353        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
 354                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 355
 356        /* If the INIT is coming toward a closing socket, we'll send back
 357         * and ABORT.  Essentially, this catches the race of INIT being
 358         * backloged to the socket at the same time as the user isses close().
 359         * Since the socket and all its associations are going away, we
 360         * can treat this OOTB
 361         */
 362        if (sctp_sstate(ep->base.sk, CLOSING))
 363                return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
 364
 365        /* Verify the INIT chunk before processing it. */
 366        err_chunk = NULL;
 367        if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type,
 368                              (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
 369                              &err_chunk)) {
 370                /* This chunk contains fatal error. It is to be discarded.
 371                 * Send an ABORT, with causes if there is any.
 372                 */
 373                if (err_chunk) {
 374                        packet = sctp_abort_pkt_new(net, ep, asoc, arg,
 375                                        (__u8 *)(err_chunk->chunk_hdr) +
 376                                        sizeof(sctp_chunkhdr_t),
 377                                        ntohs(err_chunk->chunk_hdr->length) -
 378                                        sizeof(sctp_chunkhdr_t));
 379
 380                        sctp_chunk_free(err_chunk);
 381
 382                        if (packet) {
 383                                sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
 384                                                SCTP_PACKET(packet));
 385                                SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
 386                                return SCTP_DISPOSITION_CONSUME;
 387                        } else {
 388                                return SCTP_DISPOSITION_NOMEM;
 389                        }
 390                } else {
 391                        return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
 392                                                    commands);
 393                }
 394        }
 395
 396        /* Grab the INIT header.  */
 397        chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data;
 398
 399        /* Tag the variable length parameters.  */
 400        chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
 401
 402        new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
 403        if (!new_asoc)
 404                goto nomem;
 405
 406        if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
 407                                             sctp_scope(sctp_source(chunk)),
 408                                             GFP_ATOMIC) < 0)
 409                goto nomem_init;
 410
 411        /* The call, sctp_process_init(), can fail on memory allocation.  */
 412        if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
 413                               (sctp_init_chunk_t *)chunk->chunk_hdr,
 414                               GFP_ATOMIC))
 415                goto nomem_init;
 416
 417        /* B) "Z" shall respond immediately with an INIT ACK chunk.  */
 418
 419        /* If there are errors need to be reported for unknown parameters,
 420         * make sure to reserve enough room in the INIT ACK for them.
 421         */
 422        len = 0;
 423        if (err_chunk)
 424                len = ntohs(err_chunk->chunk_hdr->length) -
 425                        sizeof(sctp_chunkhdr_t);
 426
 427        repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
 428        if (!repl)
 429                goto nomem_init;
 430
 431        /* If there are errors need to be reported for unknown parameters,
 432         * include them in the outgoing INIT ACK as "Unrecognized parameter"
 433         * parameter.
 434         */
 435        if (err_chunk) {
 436                /* Get the "Unrecognized parameter" parameter(s) out of the
 437                 * ERROR chunk generated by sctp_verify_init(). Since the
 438                 * error cause code for "unknown parameter" and the
 439                 * "Unrecognized parameter" type is the same, we can
 440                 * construct the parameters in INIT ACK by copying the
 441                 * ERROR causes over.
 442                 */
 443                unk_param = (sctp_unrecognized_param_t *)
 444                            ((__u8 *)(err_chunk->chunk_hdr) +
 445                            sizeof(sctp_chunkhdr_t));
 446                /* Replace the cause code with the "Unrecognized parameter"
 447                 * parameter type.
 448                 */
 449                sctp_addto_chunk(repl, len, unk_param);
 450                sctp_chunk_free(err_chunk);
 451        }
 452
 453        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
 454
 455        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
 456
 457        /*
 458         * Note:  After sending out INIT ACK with the State Cookie parameter,
 459         * "Z" MUST NOT allocate any resources, nor keep any states for the
 460         * new association.  Otherwise, "Z" will be vulnerable to resource
 461         * attacks.
 462         */
 463        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
 464
 465        return SCTP_DISPOSITION_DELETE_TCB;
 466
 467nomem_init:
 468        sctp_association_free(new_asoc);
 469nomem:
 470        if (err_chunk)
 471                sctp_chunk_free(err_chunk);
 472        return SCTP_DISPOSITION_NOMEM;
 473}
 474
 475/*
 476 * Respond to a normal INIT ACK chunk.
 477 * We are the side that is initiating the association.
 478 *
 479 * Section: 5.1 Normal Establishment of an Association, C
 480 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
 481 *    timer and leave COOKIE-WAIT state. "A" shall then send the State
 482 *    Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
 483 *    the T1-cookie timer, and enter the COOKIE-ECHOED state.
 484 *
 485 *    Note: The COOKIE ECHO chunk can be bundled with any pending outbound
 486 *    DATA chunks, but it MUST be the first chunk in the packet and
 487 *    until the COOKIE ACK is returned the sender MUST NOT send any
 488 *    other packets to the peer.
 489 *
 490 * Verification Tag: 3.3.3
 491 *   If the value of the Initiate Tag in a received INIT ACK chunk is
 492 *   found to be 0, the receiver MUST treat it as an error and close the
 493 *   association by transmitting an ABORT.
 494 *
 495 * Inputs
 496 * (endpoint, asoc, chunk)
 497 *
 498 * Outputs
 499 * (asoc, reply_msg, msg_up, timers, counters)
 500 *
 501 * The return value is the disposition of the chunk.
 502 */
 503sctp_disposition_t sctp_sf_do_5_1C_ack(struct net *net,
 504                                       const struct sctp_endpoint *ep,
 505                                       const struct sctp_association *asoc,
 506                                       const sctp_subtype_t type,
 507                                       void *arg,
 508                                       sctp_cmd_seq_t *commands)
 509{
 510        struct sctp_chunk *chunk = arg;
 511        sctp_init_chunk_t *initchunk;
 512        struct sctp_chunk *err_chunk;
 513        struct sctp_packet *packet;
 514
 515        if (!sctp_vtag_verify(chunk, asoc))
 516                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 517
 518        /* 6.10 Bundling
 519         * An endpoint MUST NOT bundle INIT, INIT ACK or
 520         * SHUTDOWN COMPLETE with any other chunks.
 521         */
 522        if (!chunk->singleton)
 523                return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
 524
 525        /* Make sure that the INIT-ACK chunk has a valid length */
 526        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t)))
 527                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
 528                                                  commands);
 529        /* Grab the INIT header.  */
 530        chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
 531
 532        /* Verify the INIT chunk before processing it. */
 533        err_chunk = NULL;
 534        if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type,
 535                              (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
 536                              &err_chunk)) {
 537
 538                sctp_error_t error = SCTP_ERROR_NO_RESOURCE;
 539
 540                /* This chunk contains fatal error. It is to be discarded.
 541                 * Send an ABORT, with causes.  If there are no causes,
 542                 * then there wasn't enough memory.  Just terminate
 543                 * the association.
 544                 */
 545                if (err_chunk) {
 546                        packet = sctp_abort_pkt_new(net, ep, asoc, arg,
 547                                        (__u8 *)(err_chunk->chunk_hdr) +
 548                                        sizeof(sctp_chunkhdr_t),
 549                                        ntohs(err_chunk->chunk_hdr->length) -
 550                                        sizeof(sctp_chunkhdr_t));
 551
 552                        sctp_chunk_free(err_chunk);
 553
 554                        if (packet) {
 555                                sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
 556                                                SCTP_PACKET(packet));
 557                                SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
 558                                error = SCTP_ERROR_INV_PARAM;
 559                        }
 560                }
 561
 562                /* SCTP-AUTH, Section 6.3:
 563                 *    It should be noted that if the receiver wants to tear
 564                 *    down an association in an authenticated way only, the
 565                 *    handling of malformed packets should not result in
 566                 *    tearing down the association.
 567                 *
 568                 * This means that if we only want to abort associations
 569                 * in an authenticated way (i.e AUTH+ABORT), then we
 570                 * can't destroy this association just because the packet
 571                 * was malformed.
 572                 */
 573                if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
 574                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 575
 576                SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
 577                return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED,
 578                                                asoc, chunk->transport);
 579        }
 580
 581        /* Tag the variable length parameters.  Note that we never
 582         * convert the parameters in an INIT chunk.
 583         */
 584        chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
 585
 586        initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr;
 587
 588        sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
 589                        SCTP_PEER_INIT(initchunk));
 590
 591        /* Reset init error count upon receipt of INIT-ACK.  */
 592        sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
 593
 594        /* 5.1 C) "A" shall stop the T1-init timer and leave
 595         * COOKIE-WAIT state.  "A" shall then ... start the T1-cookie
 596         * timer, and enter the COOKIE-ECHOED state.
 597         */
 598        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 599                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
 600        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
 601                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
 602        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 603                        SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
 604
 605        /* SCTP-AUTH: genereate the assocition shared keys so that
 606         * we can potentially signe the COOKIE-ECHO.
 607         */
 608        sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
 609
 610        /* 5.1 C) "A" shall then send the State Cookie received in the
 611         * INIT ACK chunk in a COOKIE ECHO chunk, ...
 612         */
 613        /* If there is any errors to report, send the ERROR chunk generated
 614         * for unknown parameters as well.
 615         */
 616        sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
 617                        SCTP_CHUNK(err_chunk));
 618
 619        return SCTP_DISPOSITION_CONSUME;
 620}
 621
 622/*
 623 * Respond to a normal COOKIE ECHO chunk.
 624 * We are the side that is being asked for an association.
 625 *
 626 * Section: 5.1 Normal Establishment of an Association, D
 627 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
 628 *    with a COOKIE ACK chunk after building a TCB and moving to
 629 *    the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
 630 *    any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
 631 *    chunk MUST be the first chunk in the packet.
 632 *
 633 *   IMPLEMENTATION NOTE: An implementation may choose to send the
 634 *   Communication Up notification to the SCTP user upon reception
 635 *   of a valid COOKIE ECHO chunk.
 636 *
 637 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
 638 * D) Rules for packet carrying a COOKIE ECHO
 639 *
 640 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
 641 *   Initial Tag received in the INIT ACK.
 642 *
 643 * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
 644 *
 645 * Inputs
 646 * (endpoint, asoc, chunk)
 647 *
 648 * Outputs
 649 * (asoc, reply_msg, msg_up, timers, counters)
 650 *
 651 * The return value is the disposition of the chunk.
 652 */
 653sctp_disposition_t sctp_sf_do_5_1D_ce(struct net *net,
 654                                      const struct sctp_endpoint *ep,
 655                                      const struct sctp_association *asoc,
 656                                      const sctp_subtype_t type, void *arg,
 657                                      sctp_cmd_seq_t *commands)
 658{
 659        struct sctp_chunk *chunk = arg;
 660        struct sctp_association *new_asoc;
 661        sctp_init_chunk_t *peer_init;
 662        struct sctp_chunk *repl;
 663        struct sctp_ulpevent *ev, *ai_ev = NULL;
 664        int error = 0;
 665        struct sctp_chunk *err_chk_p;
 666        struct sock *sk;
 667
 668        /* If the packet is an OOTB packet which is temporarily on the
 669         * control endpoint, respond with an ABORT.
 670         */
 671        if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
 672                SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
 673                return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
 674        }
 675
 676        /* Make sure that the COOKIE_ECHO chunk has a valid length.
 677         * In this case, we check that we have enough for at least a
 678         * chunk header.  More detailed verification is done
 679         * in sctp_unpack_cookie().
 680         */
 681        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
 682                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 683
 684        /* If the endpoint is not listening or if the number of associations
 685         * on the TCP-style socket exceed the max backlog, respond with an
 686         * ABORT.
 687         */
 688        sk = ep->base.sk;
 689        if (!sctp_sstate(sk, LISTENING) ||
 690            (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
 691                return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
 692
 693        /* "Decode" the chunk.  We have no optional parameters so we
 694         * are in good shape.
 695         */
 696        chunk->subh.cookie_hdr =
 697                (struct sctp_signed_cookie *)chunk->skb->data;
 698        if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
 699                                         sizeof(sctp_chunkhdr_t)))
 700                goto nomem;
 701
 702        /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
 703         * "Z" will reply with a COOKIE ACK chunk after building a TCB
 704         * and moving to the ESTABLISHED state.
 705         */
 706        new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
 707                                      &err_chk_p);
 708
 709        /* FIXME:
 710         * If the re-build failed, what is the proper error path
 711         * from here?
 712         *
 713         * [We should abort the association. --piggy]
 714         */
 715        if (!new_asoc) {
 716                /* FIXME: Several errors are possible.  A bad cookie should
 717                 * be silently discarded, but think about logging it too.
 718                 */
 719                switch (error) {
 720                case -SCTP_IERROR_NOMEM:
 721                        goto nomem;
 722
 723                case -SCTP_IERROR_STALE_COOKIE:
 724                        sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
 725                                                   err_chk_p);
 726                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 727
 728                case -SCTP_IERROR_BAD_SIG:
 729                default:
 730                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 731                }
 732        }
 733
 734
 735        /* Delay state machine commands until later.
 736         *
 737         * Re-build the bind address for the association is done in
 738         * the sctp_unpack_cookie() already.
 739         */
 740        /* This is a brand-new association, so these are not yet side
 741         * effects--it is safe to run them here.
 742         */
 743        peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
 744
 745        if (!sctp_process_init(new_asoc, chunk,
 746                               &chunk->subh.cookie_hdr->c.peer_addr,
 747                               peer_init, GFP_ATOMIC))
 748                goto nomem_init;
 749
 750        /* SCTP-AUTH:  Now that we've populate required fields in
 751         * sctp_process_init, set up the assocaition shared keys as
 752         * necessary so that we can potentially authenticate the ACK
 753         */
 754        error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
 755        if (error)
 756                goto nomem_init;
 757
 758        /* SCTP-AUTH:  auth_chunk pointer is only set when the cookie-echo
 759         * is supposed to be authenticated and we have to do delayed
 760         * authentication.  We've just recreated the association using
 761         * the information in the cookie and now it's much easier to
 762         * do the authentication.
 763         */
 764        if (chunk->auth_chunk) {
 765                struct sctp_chunk auth;
 766                sctp_ierror_t ret;
 767
 768                /* set-up our fake chunk so that we can process it */
 769                auth.skb = chunk->auth_chunk;
 770                auth.asoc = chunk->asoc;
 771                auth.sctp_hdr = chunk->sctp_hdr;
 772                auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk,
 773                                            sizeof(sctp_chunkhdr_t));
 774                skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t));
 775                auth.transport = chunk->transport;
 776
 777                ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth);
 778
 779                /* We can now safely free the auth_chunk clone */
 780                kfree_skb(chunk->auth_chunk);
 781
 782                if (ret != SCTP_IERROR_NO_ERROR) {
 783                        sctp_association_free(new_asoc);
 784                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 785                }
 786        }
 787
 788        repl = sctp_make_cookie_ack(new_asoc, chunk);
 789        if (!repl)
 790                goto nomem_init;
 791
 792        /* RFC 2960 5.1 Normal Establishment of an Association
 793         *
 794         * D) IMPLEMENTATION NOTE: An implementation may choose to
 795         * send the Communication Up notification to the SCTP user
 796         * upon reception of a valid COOKIE ECHO chunk.
 797         */
 798        ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
 799                                             new_asoc->c.sinit_num_ostreams,
 800                                             new_asoc->c.sinit_max_instreams,
 801                                             NULL, GFP_ATOMIC);
 802        if (!ev)
 803                goto nomem_ev;
 804
 805        /* Sockets API Draft Section 5.3.1.6
 806         * When a peer sends a Adaptation Layer Indication parameter , SCTP
 807         * delivers this notification to inform the application that of the
 808         * peers requested adaptation layer.
 809         */
 810        if (new_asoc->peer.adaptation_ind) {
 811                ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
 812                                                            GFP_ATOMIC);
 813                if (!ai_ev)
 814                        goto nomem_aiev;
 815        }
 816
 817        /* Add all the state machine commands now since we've created
 818         * everything.  This way we don't introduce memory corruptions
 819         * during side-effect processing and correclty count established
 820         * associations.
 821         */
 822        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
 823        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 824                        SCTP_STATE(SCTP_STATE_ESTABLISHED));
 825        SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
 826        SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS);
 827        sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
 828
 829        if (new_asoc->autoclose)
 830                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
 831                                SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
 832
 833        /* This will send the COOKIE ACK */
 834        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
 835
 836        /* Queue the ASSOC_CHANGE event */
 837        sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
 838
 839        /* Send up the Adaptation Layer Indication event */
 840        if (ai_ev)
 841                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 842                                SCTP_ULPEVENT(ai_ev));
 843
 844        return SCTP_DISPOSITION_CONSUME;
 845
 846nomem_aiev:
 847        sctp_ulpevent_free(ev);
 848nomem_ev:
 849        sctp_chunk_free(repl);
 850nomem_init:
 851        sctp_association_free(new_asoc);
 852nomem:
 853        return SCTP_DISPOSITION_NOMEM;
 854}
 855
 856/*
 857 * Respond to a normal COOKIE ACK chunk.
 858 * We are the side that is being asked for an association.
 859 *
 860 * RFC 2960 5.1 Normal Establishment of an Association
 861 *
 862 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
 863 *    COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
 864 *    timer. It may also notify its ULP about the successful
 865 *    establishment of the association with a Communication Up
 866 *    notification (see Section 10).
 867 *
 868 * Verification Tag:
 869 * Inputs
 870 * (endpoint, asoc, chunk)
 871 *
 872 * Outputs
 873 * (asoc, reply_msg, msg_up, timers, counters)
 874 *
 875 * The return value is the disposition of the chunk.
 876 */
 877sctp_disposition_t sctp_sf_do_5_1E_ca(struct net *net,
 878                                      const struct sctp_endpoint *ep,
 879                                      const struct sctp_association *asoc,
 880                                      const sctp_subtype_t type, void *arg,
 881                                      sctp_cmd_seq_t *commands)
 882{
 883        struct sctp_chunk *chunk = arg;
 884        struct sctp_ulpevent *ev;
 885
 886        if (!sctp_vtag_verify(chunk, asoc))
 887                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 888
 889        /* Verify that the chunk length for the COOKIE-ACK is OK.
 890         * If we don't do this, any bundled chunks may be junked.
 891         */
 892        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
 893                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
 894                                                  commands);
 895
 896        /* Reset init error count upon receipt of COOKIE-ACK,
 897         * to avoid problems with the managemement of this
 898         * counter in stale cookie situations when a transition back
 899         * from the COOKIE-ECHOED state to the COOKIE-WAIT
 900         * state is performed.
 901         */
 902        sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
 903
 904        /* RFC 2960 5.1 Normal Establishment of an Association
 905         *
 906         * E) Upon reception of the COOKIE ACK, endpoint "A" will move
 907         * from the COOKIE-ECHOED state to the ESTABLISHED state,
 908         * stopping the T1-cookie timer.
 909         */
 910        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 911                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
 912        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
 913                        SCTP_STATE(SCTP_STATE_ESTABLISHED));
 914        SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
 915        SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS);
 916        sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
 917        if (asoc->autoclose)
 918                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
 919                                SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
 920
 921        /* It may also notify its ULP about the successful
 922         * establishment of the association with a Communication Up
 923         * notification (see Section 10).
 924         */
 925        ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
 926                                             0, asoc->c.sinit_num_ostreams,
 927                                             asoc->c.sinit_max_instreams,
 928                                             NULL, GFP_ATOMIC);
 929
 930        if (!ev)
 931                goto nomem;
 932
 933        sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
 934
 935        /* Sockets API Draft Section 5.3.1.6
 936         * When a peer sends a Adaptation Layer Indication parameter , SCTP
 937         * delivers this notification to inform the application that of the
 938         * peers requested adaptation layer.
 939         */
 940        if (asoc->peer.adaptation_ind) {
 941                ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
 942                if (!ev)
 943                        goto nomem;
 944
 945                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
 946                                SCTP_ULPEVENT(ev));
 947        }
 948
 949        return SCTP_DISPOSITION_CONSUME;
 950nomem:
 951        return SCTP_DISPOSITION_NOMEM;
 952}
 953
 954/* Generate and sendout a heartbeat packet.  */
 955static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep,
 956                                            const struct sctp_association *asoc,
 957                                            const sctp_subtype_t type,
 958                                            void *arg,
 959                                            sctp_cmd_seq_t *commands)
 960{
 961        struct sctp_transport *transport = (struct sctp_transport *) arg;
 962        struct sctp_chunk *reply;
 963
 964        /* Send a heartbeat to our peer.  */
 965        reply = sctp_make_heartbeat(asoc, transport);
 966        if (!reply)
 967                return SCTP_DISPOSITION_NOMEM;
 968
 969        /* Set rto_pending indicating that an RTT measurement
 970         * is started with this heartbeat chunk.
 971         */
 972        sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
 973                        SCTP_TRANSPORT(transport));
 974
 975        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
 976        return SCTP_DISPOSITION_CONSUME;
 977}
 978
 979/* Generate a HEARTBEAT packet on the given transport.  */
 980sctp_disposition_t sctp_sf_sendbeat_8_3(struct net *net,
 981                                        const struct sctp_endpoint *ep,
 982                                        const struct sctp_association *asoc,
 983                                        const sctp_subtype_t type,
 984                                        void *arg,
 985                                        sctp_cmd_seq_t *commands)
 986{
 987        struct sctp_transport *transport = (struct sctp_transport *) arg;
 988
 989        if (asoc->overall_error_count >= asoc->max_retrans) {
 990                sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
 991                                SCTP_ERROR(ETIMEDOUT));
 992                /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
 993                sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
 994                                SCTP_PERR(SCTP_ERROR_NO_ERROR));
 995                SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
 996                SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
 997                return SCTP_DISPOSITION_DELETE_TCB;
 998        }
 999
1000        /* Section 3.3.5.
1001         * The Sender-specific Heartbeat Info field should normally include
1002         * information about the sender's current time when this HEARTBEAT
1003         * chunk is sent and the destination transport address to which this
1004         * HEARTBEAT is sent (see Section 8.3).
1005         */
1006
1007        if (transport->param_flags & SPP_HB_ENABLE) {
1008                if (SCTP_DISPOSITION_NOMEM ==
1009                                sctp_sf_heartbeat(ep, asoc, type, arg,
1010                                                  commands))
1011                        return SCTP_DISPOSITION_NOMEM;
1012
1013                /* Set transport error counter and association error counter
1014                 * when sending heartbeat.
1015                 */
1016                sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
1017                                SCTP_TRANSPORT(transport));
1018        }
1019        sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE,
1020                        SCTP_TRANSPORT(transport));
1021        sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
1022                        SCTP_TRANSPORT(transport));
1023
1024        return SCTP_DISPOSITION_CONSUME;
1025}
1026
1027/*
1028 * Process an heartbeat request.
1029 *
1030 * Section: 8.3 Path Heartbeat
1031 * The receiver of the HEARTBEAT should immediately respond with a
1032 * HEARTBEAT ACK that contains the Heartbeat Information field copied
1033 * from the received HEARTBEAT chunk.
1034 *
1035 * Verification Tag:  8.5 Verification Tag [Normal verification]
1036 * When receiving an SCTP packet, the endpoint MUST ensure that the
1037 * value in the Verification Tag field of the received SCTP packet
1038 * matches its own Tag. If the received Verification Tag value does not
1039 * match the receiver's own tag value, the receiver shall silently
1040 * discard the packet and shall not process it any further except for
1041 * those cases listed in Section 8.5.1 below.
1042 *
1043 * Inputs
1044 * (endpoint, asoc, chunk)
1045 *
1046 * Outputs
1047 * (asoc, reply_msg, msg_up, timers, counters)
1048 *
1049 * The return value is the disposition of the chunk.
1050 */
1051sctp_disposition_t sctp_sf_beat_8_3(struct net *net,
1052                                    const struct sctp_endpoint *ep,
1053                                    const struct sctp_association *asoc,
1054                                    const sctp_subtype_t type,
1055                                    void *arg,
1056                                    sctp_cmd_seq_t *commands)
1057{
1058        struct sctp_chunk *chunk = arg;
1059        struct sctp_chunk *reply;
1060        size_t paylen = 0;
1061
1062        if (!sctp_vtag_verify(chunk, asoc))
1063                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1064
1065        /* Make sure that the HEARTBEAT chunk has a valid length. */
1066        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t)))
1067                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1068                                                  commands);
1069
1070        /* 8.3 The receiver of the HEARTBEAT should immediately
1071         * respond with a HEARTBEAT ACK that contains the Heartbeat
1072         * Information field copied from the received HEARTBEAT chunk.
1073         */
1074        chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data;
1075        paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
1076        if (!pskb_pull(chunk->skb, paylen))
1077                goto nomem;
1078
1079        reply = sctp_make_heartbeat_ack(asoc, chunk,
1080                                        chunk->subh.hb_hdr, paylen);
1081        if (!reply)
1082                goto nomem;
1083
1084        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1085        return SCTP_DISPOSITION_CONSUME;
1086
1087nomem:
1088        return SCTP_DISPOSITION_NOMEM;
1089}
1090
1091/*
1092 * Process the returning HEARTBEAT ACK.
1093 *
1094 * Section: 8.3 Path Heartbeat
1095 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
1096 * should clear the error counter of the destination transport
1097 * address to which the HEARTBEAT was sent, and mark the destination
1098 * transport address as active if it is not so marked. The endpoint may
1099 * optionally report to the upper layer when an inactive destination
1100 * address is marked as active due to the reception of the latest
1101 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
1102 * clear the association overall error count as well (as defined
1103 * in section 8.1).
1104 *
1105 * The receiver of the HEARTBEAT ACK should also perform an RTT
1106 * measurement for that destination transport address using the time
1107 * value carried in the HEARTBEAT ACK chunk.
1108 *
1109 * Verification Tag:  8.5 Verification Tag [Normal verification]
1110 *
1111 * Inputs
1112 * (endpoint, asoc, chunk)
1113 *
1114 * Outputs
1115 * (asoc, reply_msg, msg_up, timers, counters)
1116 *
1117 * The return value is the disposition of the chunk.
1118 */
1119sctp_disposition_t sctp_sf_backbeat_8_3(struct net *net,
1120                                        const struct sctp_endpoint *ep,
1121                                        const struct sctp_association *asoc,
1122                                        const sctp_subtype_t type,
1123                                        void *arg,
1124                                        sctp_cmd_seq_t *commands)
1125{
1126        struct sctp_chunk *chunk = arg;
1127        union sctp_addr from_addr;
1128        struct sctp_transport *link;
1129        sctp_sender_hb_info_t *hbinfo;
1130        unsigned long max_interval;
1131
1132        if (!sctp_vtag_verify(chunk, asoc))
1133                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1134
1135        /* Make sure that the HEARTBEAT-ACK chunk has a valid length.  */
1136        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) +
1137                                            sizeof(sctp_sender_hb_info_t)))
1138                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1139                                                  commands);
1140
1141        hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
1142        /* Make sure that the length of the parameter is what we expect */
1143        if (ntohs(hbinfo->param_hdr.length) !=
1144                                    sizeof(sctp_sender_hb_info_t)) {
1145                return SCTP_DISPOSITION_DISCARD;
1146        }
1147
1148        from_addr = hbinfo->daddr;
1149        link = sctp_assoc_lookup_paddr(asoc, &from_addr);
1150
1151        /* This should never happen, but lets log it if so.  */
1152        if (unlikely(!link)) {
1153                if (from_addr.sa.sa_family == AF_INET6) {
1154                        net_warn_ratelimited("%s association %p could not find address %pI6\n",
1155                                             __func__,
1156                                             asoc,
1157                                             &from_addr.v6.sin6_addr);
1158                } else {
1159                        net_warn_ratelimited("%s association %p could not find address %pI4\n",
1160                                             __func__,
1161                                             asoc,
1162                                             &from_addr.v4.sin_addr.s_addr);
1163                }
1164                return SCTP_DISPOSITION_DISCARD;
1165        }
1166
1167        /* Validate the 64-bit random nonce. */
1168        if (hbinfo->hb_nonce != link->hb_nonce)
1169                return SCTP_DISPOSITION_DISCARD;
1170
1171        max_interval = link->hbinterval + link->rto;
1172
1173        /* Check if the timestamp looks valid.  */
1174        if (time_after(hbinfo->sent_at, jiffies) ||
1175            time_after(jiffies, hbinfo->sent_at + max_interval)) {
1176                SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp "
1177                                  "received for transport: %p\n",
1178                                   __func__, link);
1179                return SCTP_DISPOSITION_DISCARD;
1180        }
1181
1182        /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
1183         * the HEARTBEAT should clear the error counter of the
1184         * destination transport address to which the HEARTBEAT was
1185         * sent and mark the destination transport address as active if
1186         * it is not so marked.
1187         */
1188        sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
1189
1190        return SCTP_DISPOSITION_CONSUME;
1191}
1192
1193/* Helper function to send out an abort for the restart
1194 * condition.
1195 */
1196static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa,
1197                                      struct sctp_chunk *init,
1198                                      sctp_cmd_seq_t *commands)
1199{
1200        int len;
1201        struct sctp_packet *pkt;
1202        union sctp_addr_param *addrparm;
1203        struct sctp_errhdr *errhdr;
1204        struct sctp_endpoint *ep;
1205        char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)];
1206        struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
1207
1208        /* Build the error on the stack.   We are way to malloc crazy
1209         * throughout the code today.
1210         */
1211        errhdr = (struct sctp_errhdr *)buffer;
1212        addrparm = (union sctp_addr_param *)errhdr->variable;
1213
1214        /* Copy into a parm format. */
1215        len = af->to_addr_param(ssa, addrparm);
1216        len += sizeof(sctp_errhdr_t);
1217
1218        errhdr->cause = SCTP_ERROR_RESTART;
1219        errhdr->length = htons(len);
1220
1221        /* Assign to the control socket. */
1222        ep = sctp_sk(net->sctp.ctl_sock)->ep;
1223
1224        /* Association is NULL since this may be a restart attack and we
1225         * want to send back the attacker's vtag.
1226         */
1227        pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len);
1228
1229        if (!pkt)
1230                goto out;
1231        sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
1232
1233        SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1234
1235        /* Discard the rest of the inbound packet. */
1236        sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
1237
1238out:
1239        /* Even if there is no memory, treat as a failure so
1240         * the packet will get dropped.
1241         */
1242        return 0;
1243}
1244
1245static bool list_has_sctp_addr(const struct list_head *list,
1246                               union sctp_addr *ipaddr)
1247{
1248        struct sctp_transport *addr;
1249
1250        list_for_each_entry(addr, list, transports) {
1251                if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr))
1252                        return true;
1253        }
1254
1255        return false;
1256}
1257/* A restart is occurring, check to make sure no new addresses
1258 * are being added as we may be under a takeover attack.
1259 */
1260static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
1261                                       const struct sctp_association *asoc,
1262                                       struct sctp_chunk *init,
1263                                       sctp_cmd_seq_t *commands)
1264{
1265        struct net *net = sock_net(new_asoc->base.sk);
1266        struct sctp_transport *new_addr;
1267        int ret = 1;
1268
1269        /* Implementor's Guide - Section 5.2.2
1270         * ...
1271         * Before responding the endpoint MUST check to see if the
1272         * unexpected INIT adds new addresses to the association. If new
1273         * addresses are added to the association, the endpoint MUST respond
1274         * with an ABORT..
1275         */
1276
1277        /* Search through all current addresses and make sure
1278         * we aren't adding any new ones.
1279         */
1280        list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
1281                            transports) {
1282                if (!list_has_sctp_addr(&asoc->peer.transport_addr_list,
1283                                        &new_addr->ipaddr)) {
1284                        sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init,
1285                                                   commands);
1286                        ret = 0;
1287                        break;
1288                }
1289        }
1290
1291        /* Return success if all addresses were found. */
1292        return ret;
1293}
1294
1295/* Populate the verification/tie tags based on overlapping INIT
1296 * scenario.
1297 *
1298 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1299 */
1300static void sctp_tietags_populate(struct sctp_association *new_asoc,
1301                                  const struct sctp_association *asoc)
1302{
1303        switch (asoc->state) {
1304
1305        /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1306
1307        case SCTP_STATE_COOKIE_WAIT:
1308                new_asoc->c.my_vtag     = asoc->c.my_vtag;
1309                new_asoc->c.my_ttag     = asoc->c.my_vtag;
1310                new_asoc->c.peer_ttag   = 0;
1311                break;
1312
1313        case SCTP_STATE_COOKIE_ECHOED:
1314                new_asoc->c.my_vtag     = asoc->c.my_vtag;
1315                new_asoc->c.my_ttag     = asoc->c.my_vtag;
1316                new_asoc->c.peer_ttag   = asoc->c.peer_vtag;
1317                break;
1318
1319        /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1320         * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1321         */
1322        default:
1323                new_asoc->c.my_ttag   = asoc->c.my_vtag;
1324                new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1325                break;
1326        }
1327
1328        /* Other parameters for the endpoint SHOULD be copied from the
1329         * existing parameters of the association (e.g. number of
1330         * outbound streams) into the INIT ACK and cookie.
1331         */
1332        new_asoc->rwnd                  = asoc->rwnd;
1333        new_asoc->c.sinit_num_ostreams  = asoc->c.sinit_num_ostreams;
1334        new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
1335        new_asoc->c.initial_tsn         = asoc->c.initial_tsn;
1336}
1337
1338/*
1339 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1340 * handling action.
1341 *
1342 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1343 *
1344 * Returns value representing action to be taken.   These action values
1345 * correspond to Action/Description values in RFC 2960, Table 2.
1346 */
1347static char sctp_tietags_compare(struct sctp_association *new_asoc,
1348                                 const struct sctp_association *asoc)
1349{
1350        /* In this case, the peer may have restarted.  */
1351        if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1352            (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
1353            (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
1354            (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
1355                return 'A';
1356
1357        /* Collision case B. */
1358        if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1359            ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
1360             (0 == asoc->c.peer_vtag))) {
1361                return 'B';
1362        }
1363
1364        /* Collision case D. */
1365        if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1366            (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
1367                return 'D';
1368
1369        /* Collision case C. */
1370        if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1371            (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
1372            (0 == new_asoc->c.my_ttag) &&
1373            (0 == new_asoc->c.peer_ttag))
1374                return 'C';
1375
1376        /* No match to any of the special cases; discard this packet. */
1377        return 'E';
1378}
1379
1380/* Common helper routine for both duplicate and simulataneous INIT
1381 * chunk handling.
1382 */
1383static sctp_disposition_t sctp_sf_do_unexpected_init(
1384        struct net *net,
1385        const struct sctp_endpoint *ep,
1386        const struct sctp_association *asoc,
1387        const sctp_subtype_t type,
1388        void *arg, sctp_cmd_seq_t *commands)
1389{
1390        sctp_disposition_t retval;
1391        struct sctp_chunk *chunk = arg;
1392        struct sctp_chunk *repl;
1393        struct sctp_association *new_asoc;
1394        struct sctp_chunk *err_chunk;
1395        struct sctp_packet *packet;
1396        sctp_unrecognized_param_t *unk_param;
1397        int len;
1398
1399        /* 6.10 Bundling
1400         * An endpoint MUST NOT bundle INIT, INIT ACK or
1401         * SHUTDOWN COMPLETE with any other chunks.
1402         *
1403         * IG Section 2.11.2
1404         * Furthermore, we require that the receiver of an INIT chunk MUST
1405         * enforce these rules by silently discarding an arriving packet
1406         * with an INIT chunk that is bundled with other chunks.
1407         */
1408        if (!chunk->singleton)
1409                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1410
1411        /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1412         * Tag.
1413         */
1414        if (chunk->sctp_hdr->vtag != 0)
1415                return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
1416
1417        /* Make sure that the INIT chunk has a valid length.
1418         * In this case, we generate a protocol violation since we have
1419         * an association established.
1420         */
1421        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
1422                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1423                                                  commands);
1424        /* Grab the INIT header.  */
1425        chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
1426
1427        /* Tag the variable length parameters.  */
1428        chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
1429
1430        /* Verify the INIT chunk before processing it. */
1431        err_chunk = NULL;
1432        if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type,
1433                              (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
1434                              &err_chunk)) {
1435                /* This chunk contains fatal error. It is to be discarded.
1436                 * Send an ABORT, with causes if there is any.
1437                 */
1438                if (err_chunk) {
1439                        packet = sctp_abort_pkt_new(net, ep, asoc, arg,
1440                                        (__u8 *)(err_chunk->chunk_hdr) +
1441                                        sizeof(sctp_chunkhdr_t),
1442                                        ntohs(err_chunk->chunk_hdr->length) -
1443                                        sizeof(sctp_chunkhdr_t));
1444
1445                        if (packet) {
1446                                sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
1447                                                SCTP_PACKET(packet));
1448                                SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1449                                retval = SCTP_DISPOSITION_CONSUME;
1450                        } else {
1451                                retval = SCTP_DISPOSITION_NOMEM;
1452                        }
1453                        goto cleanup;
1454                } else {
1455                        return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
1456                                                    commands);
1457                }
1458        }
1459
1460        /*
1461         * Other parameters for the endpoint SHOULD be copied from the
1462         * existing parameters of the association (e.g. number of
1463         * outbound streams) into the INIT ACK and cookie.
1464         * FIXME:  We are copying parameters from the endpoint not the
1465         * association.
1466         */
1467        new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
1468        if (!new_asoc)
1469                goto nomem;
1470
1471        if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
1472                                sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0)
1473                goto nomem;
1474
1475        /* In the outbound INIT ACK the endpoint MUST copy its current
1476         * Verification Tag and Peers Verification tag into a reserved
1477         * place (local tie-tag and per tie-tag) within the state cookie.
1478         */
1479        if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
1480                               (sctp_init_chunk_t *)chunk->chunk_hdr,
1481                               GFP_ATOMIC))
1482                goto nomem;
1483
1484        /* Make sure no new addresses are being added during the
1485         * restart.   Do not do this check for COOKIE-WAIT state,
1486         * since there are no peer addresses to check against.
1487         * Upon return an ABORT will have been sent if needed.
1488         */
1489        if (!sctp_state(asoc, COOKIE_WAIT)) {
1490                if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
1491                                                 commands)) {
1492                        retval = SCTP_DISPOSITION_CONSUME;
1493                        goto nomem_retval;
1494                }
1495        }
1496
1497        sctp_tietags_populate(new_asoc, asoc);
1498
1499        /* B) "Z" shall respond immediately with an INIT ACK chunk.  */
1500
1501        /* If there are errors need to be reported for unknown parameters,
1502         * make sure to reserve enough room in the INIT ACK for them.
1503         */
1504        len = 0;
1505        if (err_chunk) {
1506                len = ntohs(err_chunk->chunk_hdr->length) -
1507                        sizeof(sctp_chunkhdr_t);
1508        }
1509
1510        repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
1511        if (!repl)
1512                goto nomem;
1513
1514        /* If there are errors need to be reported for unknown parameters,
1515         * include them in the outgoing INIT ACK as "Unrecognized parameter"
1516         * parameter.
1517         */
1518        if (err_chunk) {
1519                /* Get the "Unrecognized parameter" parameter(s) out of the
1520                 * ERROR chunk generated by sctp_verify_init(). Since the
1521                 * error cause code for "unknown parameter" and the
1522                 * "Unrecognized parameter" type is the same, we can
1523                 * construct the parameters in INIT ACK by copying the
1524                 * ERROR causes over.
1525                 */
1526                unk_param = (sctp_unrecognized_param_t *)
1527                            ((__u8 *)(err_chunk->chunk_hdr) +
1528                            sizeof(sctp_chunkhdr_t));
1529                /* Replace the cause code with the "Unrecognized parameter"
1530                 * parameter type.
1531                 */
1532                sctp_addto_chunk(repl, len, unk_param);
1533        }
1534
1535        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
1536        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1537
1538        /*
1539         * Note: After sending out INIT ACK with the State Cookie parameter,
1540         * "Z" MUST NOT allocate any resources for this new association.
1541         * Otherwise, "Z" will be vulnerable to resource attacks.
1542         */
1543        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1544        retval = SCTP_DISPOSITION_CONSUME;
1545
1546        return retval;
1547
1548nomem:
1549        retval = SCTP_DISPOSITION_NOMEM;
1550nomem_retval:
1551        if (new_asoc)
1552                sctp_association_free(new_asoc);
1553cleanup:
1554        if (err_chunk)
1555                sctp_chunk_free(err_chunk);
1556        return retval;
1557}
1558
1559/*
1560 * Handle simultaneous INIT.
1561 * This means we started an INIT and then we got an INIT request from
1562 * our peer.
1563 *
1564 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
1565 * This usually indicates an initialization collision, i.e., each
1566 * endpoint is attempting, at about the same time, to establish an
1567 * association with the other endpoint.
1568 *
1569 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
1570 * endpoint MUST respond with an INIT ACK using the same parameters it
1571 * sent in its original INIT chunk (including its Verification Tag,
1572 * unchanged). These original parameters are combined with those from the
1573 * newly received INIT chunk. The endpoint shall also generate a State
1574 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
1575 * INIT to calculate the State Cookie.
1576 *
1577 * After that, the endpoint MUST NOT change its state, the T1-init
1578 * timer shall be left running and the corresponding TCB MUST NOT be
1579 * destroyed. The normal procedures for handling State Cookies when
1580 * a TCB exists will resolve the duplicate INITs to a single association.
1581 *
1582 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
1583 * its Tie-Tags with the Tag information of itself and its peer (see
1584 * section 5.2.2 for a description of the Tie-Tags).
1585 *
1586 * Verification Tag: Not explicit, but an INIT can not have a valid
1587 * verification tag, so we skip the check.
1588 *
1589 * Inputs
1590 * (endpoint, asoc, chunk)
1591 *
1592 * Outputs
1593 * (asoc, reply_msg, msg_up, timers, counters)
1594 *
1595 * The return value is the disposition of the chunk.
1596 */
1597sctp_disposition_t sctp_sf_do_5_2_1_siminit(struct net *net,
1598                                    const struct sctp_endpoint *ep,
1599                                    const struct sctp_association *asoc,
1600                                    const sctp_subtype_t type,
1601                                    void *arg,
1602                                    sctp_cmd_seq_t *commands)
1603{
1604        /* Call helper to do the real work for both simulataneous and
1605         * duplicate INIT chunk handling.
1606         */
1607        return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1608}
1609
1610/*
1611 * Handle duplicated INIT messages.  These are usually delayed
1612 * restransmissions.
1613 *
1614 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
1615 * COOKIE-ECHOED and COOKIE-WAIT
1616 *
1617 * Unless otherwise stated, upon reception of an unexpected INIT for
1618 * this association, the endpoint shall generate an INIT ACK with a
1619 * State Cookie.  In the outbound INIT ACK the endpoint MUST copy its
1620 * current Verification Tag and peer's Verification Tag into a reserved
1621 * place within the state cookie.  We shall refer to these locations as
1622 * the Peer's-Tie-Tag and the Local-Tie-Tag.  The outbound SCTP packet
1623 * containing this INIT ACK MUST carry a Verification Tag value equal to
1624 * the Initiation Tag found in the unexpected INIT.  And the INIT ACK
1625 * MUST contain a new Initiation Tag (randomly generated see Section
1626 * 5.3.1).  Other parameters for the endpoint SHOULD be copied from the
1627 * existing parameters of the association (e.g. number of outbound
1628 * streams) into the INIT ACK and cookie.
1629 *
1630 * After sending out the INIT ACK, the endpoint shall take no further
1631 * actions, i.e., the existing association, including its current state,
1632 * and the corresponding TCB MUST NOT be changed.
1633 *
1634 * Note: Only when a TCB exists and the association is not in a COOKIE-
1635 * WAIT state are the Tie-Tags populated.  For a normal association INIT
1636 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
1637 * set to 0 (indicating that no previous TCB existed).  The INIT ACK and
1638 * State Cookie are populated as specified in section 5.2.1.
1639 *
1640 * Verification Tag: Not specified, but an INIT has no way of knowing
1641 * what the verification tag could be, so we ignore it.
1642 *
1643 * Inputs
1644 * (endpoint, asoc, chunk)
1645 *
1646 * Outputs
1647 * (asoc, reply_msg, msg_up, timers, counters)
1648 *
1649 * The return value is the disposition of the chunk.
1650 */
1651sctp_disposition_t sctp_sf_do_5_2_2_dupinit(struct net *net,
1652                                        const struct sctp_endpoint *ep,
1653                                        const struct sctp_association *asoc,
1654                                        const sctp_subtype_t type,
1655                                        void *arg,
1656                                        sctp_cmd_seq_t *commands)
1657{
1658        /* Call helper to do the real work for both simulataneous and
1659         * duplicate INIT chunk handling.
1660         */
1661        return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1662}
1663
1664
1665/*
1666 * Unexpected INIT-ACK handler.
1667 *
1668 * Section 5.2.3
1669 * If an INIT ACK received by an endpoint in any state other than the
1670 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
1671 * An unexpected INIT ACK usually indicates the processing of an old or
1672 * duplicated INIT chunk.
1673*/
1674sctp_disposition_t sctp_sf_do_5_2_3_initack(struct net *net,
1675                                            const struct sctp_endpoint *ep,
1676                                            const struct sctp_association *asoc,
1677                                            const sctp_subtype_t type,
1678                                            void *arg, sctp_cmd_seq_t *commands)
1679{
1680        /* Per the above section, we'll discard the chunk if we have an
1681         * endpoint.  If this is an OOTB INIT-ACK, treat it as such.
1682         */
1683        if (ep == sctp_sk(net->sctp.ctl_sock)->ep)
1684                return sctp_sf_ootb(net, ep, asoc, type, arg, commands);
1685        else
1686                return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
1687}
1688
1689/* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1690 *
1691 * Section 5.2.4
1692 *  A)  In this case, the peer may have restarted.
1693 */
1694static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net,
1695                                        const struct sctp_endpoint *ep,
1696                                        const struct sctp_association *asoc,
1697                                        struct sctp_chunk *chunk,
1698                                        sctp_cmd_seq_t *commands,
1699                                        struct sctp_association *new_asoc)
1700{
1701        sctp_init_chunk_t *peer_init;
1702        struct sctp_ulpevent *ev;
1703        struct sctp_chunk *repl;
1704        struct sctp_chunk *err;
1705        sctp_disposition_t disposition;
1706
1707        /* new_asoc is a brand-new association, so these are not yet
1708         * side effects--it is safe to run them here.
1709         */
1710        peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1711
1712        if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1713                               GFP_ATOMIC))
1714                goto nomem;
1715
1716        /* Make sure no new addresses are being added during the
1717         * restart.  Though this is a pretty complicated attack
1718         * since you'd have to get inside the cookie.
1719         */
1720        if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) {
1721                return SCTP_DISPOSITION_CONSUME;
1722        }
1723
1724        /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1725         * the peer has restarted (Action A), it MUST NOT setup a new
1726         * association but instead resend the SHUTDOWN ACK and send an ERROR
1727         * chunk with a "Cookie Received while Shutting Down" error cause to
1728         * its peer.
1729        */
1730        if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1731                disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc,
1732                                SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1733                                chunk, commands);
1734                if (SCTP_DISPOSITION_NOMEM == disposition)
1735                        goto nomem;
1736
1737                err = sctp_make_op_error(asoc, chunk,
1738                                         SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1739                                         NULL, 0, 0);
1740                if (err)
1741                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1742                                        SCTP_CHUNK(err));
1743
1744                return SCTP_DISPOSITION_CONSUME;
1745        }
1746
1747        /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked
1748         * data. Consider the optional choice of resending of this data.
1749         */
1750        sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
1751        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1752                        SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
1753        sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1754
1755        /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
1756         * and ASCONF-ACK cache.
1757         */
1758        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1759                        SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
1760        sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
1761
1762        repl = sctp_make_cookie_ack(new_asoc, chunk);
1763        if (!repl)
1764                goto nomem;
1765
1766        /* Report association restart to upper layer. */
1767        ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1768                                             new_asoc->c.sinit_num_ostreams,
1769                                             new_asoc->c.sinit_max_instreams,
1770                                             NULL, GFP_ATOMIC);
1771        if (!ev)
1772                goto nomem_ev;
1773
1774        /* Update the content of current association. */
1775        sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1776        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1777        sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1778        return SCTP_DISPOSITION_CONSUME;
1779
1780nomem_ev:
1781        sctp_chunk_free(repl);
1782nomem:
1783        return SCTP_DISPOSITION_NOMEM;
1784}
1785
1786/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
1787 *
1788 * Section 5.2.4
1789 *   B) In this case, both sides may be attempting to start an association
1790 *      at about the same time but the peer endpoint started its INIT
1791 *      after responding to the local endpoint's INIT
1792 */
1793/* This case represents an initialization collision.  */
1794static sctp_disposition_t sctp_sf_do_dupcook_b(struct net *net,
1795                                        const struct sctp_endpoint *ep,
1796                                        const struct sctp_association *asoc,
1797                                        struct sctp_chunk *chunk,
1798                                        sctp_cmd_seq_t *commands,
1799                                        struct sctp_association *new_asoc)
1800{
1801        sctp_init_chunk_t *peer_init;
1802        struct sctp_chunk *repl;
1803
1804        /* new_asoc is a brand-new association, so these are not yet
1805         * side effects--it is safe to run them here.
1806         */
1807        peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1808        if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1809                               GFP_ATOMIC))
1810                goto nomem;
1811
1812        /* Update the content of current association.  */
1813        sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1814        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1815                        SCTP_STATE(SCTP_STATE_ESTABLISHED));
1816        SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
1817        sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
1818
1819        repl = sctp_make_cookie_ack(new_asoc, chunk);
1820        if (!repl)
1821                goto nomem;
1822
1823        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1824
1825        /* RFC 2960 5.1 Normal Establishment of an Association
1826         *
1827         * D) IMPLEMENTATION NOTE: An implementation may choose to
1828         * send the Communication Up notification to the SCTP user
1829         * upon reception of a valid COOKIE ECHO chunk.
1830         *
1831         * Sadly, this needs to be implemented as a side-effect, because
1832         * we are not guaranteed to have set the association id of the real
1833         * association and so these notifications need to be delayed until
1834         * the association id is allocated.
1835         */
1836
1837        sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
1838
1839        /* Sockets API Draft Section 5.3.1.6
1840         * When a peer sends a Adaptation Layer Indication parameter , SCTP
1841         * delivers this notification to inform the application that of the
1842         * peers requested adaptation layer.
1843         *
1844         * This also needs to be done as a side effect for the same reason as
1845         * above.
1846         */
1847        if (asoc->peer.adaptation_ind)
1848                sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
1849
1850        return SCTP_DISPOSITION_CONSUME;
1851
1852nomem:
1853        return SCTP_DISPOSITION_NOMEM;
1854}
1855
1856/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
1857 *
1858 * Section 5.2.4
1859 *  C) In this case, the local endpoint's cookie has arrived late.
1860 *     Before it arrived, the local endpoint sent an INIT and received an
1861 *     INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
1862 *     but a new tag of its own.
1863 */
1864/* This case represents an initialization collision.  */
1865static sctp_disposition_t sctp_sf_do_dupcook_c(struct net *net,
1866                                        const struct sctp_endpoint *ep,
1867                                        const struct sctp_association *asoc,
1868                                        struct sctp_chunk *chunk,
1869                                        sctp_cmd_seq_t *commands,
1870                                        struct sctp_association *new_asoc)
1871{
1872        /* The cookie should be silently discarded.
1873         * The endpoint SHOULD NOT change states and should leave
1874         * any timers running.
1875         */
1876        return SCTP_DISPOSITION_DISCARD;
1877}
1878
1879/* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
1880 *
1881 * Section 5.2.4
1882 *
1883 * D) When both local and remote tags match the endpoint should always
1884 *    enter the ESTABLISHED state, if it has not already done so.
1885 */
1886/* This case represents an initialization collision.  */
1887static sctp_disposition_t sctp_sf_do_dupcook_d(struct net *net,
1888                                        const struct sctp_endpoint *ep,
1889                                        const struct sctp_association *asoc,
1890                                        struct sctp_chunk *chunk,
1891                                        sctp_cmd_seq_t *commands,
1892                                        struct sctp_association *new_asoc)
1893{
1894        struct sctp_ulpevent *ev = NULL, *ai_ev = NULL;
1895        struct sctp_chunk *repl;
1896
1897        /* Clarification from Implementor's Guide:
1898         * D) When both local and remote tags match the endpoint should
1899         * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
1900         * It should stop any cookie timer that may be running and send
1901         * a COOKIE ACK.
1902         */
1903
1904        /* Don't accidentally move back into established state. */
1905        if (asoc->state < SCTP_STATE_ESTABLISHED) {
1906                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1907                                SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1908                sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1909                                SCTP_STATE(SCTP_STATE_ESTABLISHED));
1910                SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
1911                sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
1912                                SCTP_NULL());
1913
1914                /* RFC 2960 5.1 Normal Establishment of an Association
1915                 *
1916                 * D) IMPLEMENTATION NOTE: An implementation may choose
1917                 * to send the Communication Up notification to the
1918                 * SCTP user upon reception of a valid COOKIE
1919                 * ECHO chunk.
1920                 */
1921                ev = sctp_ulpevent_make_assoc_change(asoc, 0,
1922                                             SCTP_COMM_UP, 0,
1923                                             asoc->c.sinit_num_ostreams,
1924                                             asoc->c.sinit_max_instreams,
1925                                             NULL, GFP_ATOMIC);
1926                if (!ev)
1927                        goto nomem;
1928
1929                /* Sockets API Draft Section 5.3.1.6
1930                 * When a peer sends a Adaptation Layer Indication parameter,
1931                 * SCTP delivers this notification to inform the application
1932                 * that of the peers requested adaptation layer.
1933                 */
1934                if (asoc->peer.adaptation_ind) {
1935                        ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
1936                                                                 GFP_ATOMIC);
1937                        if (!ai_ev)
1938                                goto nomem;
1939
1940                }
1941        }
1942
1943        repl = sctp_make_cookie_ack(new_asoc, chunk);
1944        if (!repl)
1945                goto nomem;
1946
1947        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1948
1949        if (ev)
1950                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1951                                SCTP_ULPEVENT(ev));
1952        if (ai_ev)
1953                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1954                                        SCTP_ULPEVENT(ai_ev));
1955
1956        return SCTP_DISPOSITION_CONSUME;
1957
1958nomem:
1959        if (ai_ev)
1960                sctp_ulpevent_free(ai_ev);
1961        if (ev)
1962                sctp_ulpevent_free(ev);
1963        return SCTP_DISPOSITION_NOMEM;
1964}
1965
1966/*
1967 * Handle a duplicate COOKIE-ECHO.  This usually means a cookie-carrying
1968 * chunk was retransmitted and then delayed in the network.
1969 *
1970 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
1971 *
1972 * Verification Tag: None.  Do cookie validation.
1973 *
1974 * Inputs
1975 * (endpoint, asoc, chunk)
1976 *
1977 * Outputs
1978 * (asoc, reply_msg, msg_up, timers, counters)
1979 *
1980 * The return value is the disposition of the chunk.
1981 */
1982sctp_disposition_t sctp_sf_do_5_2_4_dupcook(struct net *net,
1983                                        const struct sctp_endpoint *ep,
1984                                        const struct sctp_association *asoc,
1985                                        const sctp_subtype_t type,
1986                                        void *arg,
1987                                        sctp_cmd_seq_t *commands)
1988{
1989        sctp_disposition_t retval;
1990        struct sctp_chunk *chunk = arg;
1991        struct sctp_association *new_asoc;
1992        int error = 0;
1993        char action;
1994        struct sctp_chunk *err_chk_p;
1995
1996        /* Make sure that the chunk has a valid length from the protocol
1997         * perspective.  In this case check to make sure we have at least
1998         * enough for the chunk header.  Cookie length verification is
1999         * done later.
2000         */
2001        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
2002                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2003                                                  commands);
2004
2005        /* "Decode" the chunk.  We have no optional parameters so we
2006         * are in good shape.
2007         */
2008        chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
2009        if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
2010                                        sizeof(sctp_chunkhdr_t)))
2011                goto nomem;
2012
2013        /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
2014         * of a duplicate COOKIE ECHO match the Verification Tags of the
2015         * current association, consider the State Cookie valid even if
2016         * the lifespan is exceeded.
2017         */
2018        new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
2019                                      &err_chk_p);
2020
2021        /* FIXME:
2022         * If the re-build failed, what is the proper error path
2023         * from here?
2024         *
2025         * [We should abort the association. --piggy]
2026         */
2027        if (!new_asoc) {
2028                /* FIXME: Several errors are possible.  A bad cookie should
2029                 * be silently discarded, but think about logging it too.
2030                 */
2031                switch (error) {
2032                case -SCTP_IERROR_NOMEM:
2033                        goto nomem;
2034
2035                case -SCTP_IERROR_STALE_COOKIE:
2036                        sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
2037                                                   err_chk_p);
2038                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2039                case -SCTP_IERROR_BAD_SIG:
2040                default:
2041                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2042                }
2043        }
2044
2045        /* Compare the tie_tag in cookie with the verification tag of
2046         * current association.
2047         */
2048        action = sctp_tietags_compare(new_asoc, asoc);
2049
2050        switch (action) {
2051        case 'A': /* Association restart. */
2052                retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands,
2053                                              new_asoc);
2054                break;
2055
2056        case 'B': /* Collision case B. */
2057                retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands,
2058                                              new_asoc);
2059                break;
2060
2061        case 'C': /* Collision case C. */
2062                retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands,
2063                                              new_asoc);
2064                break;
2065
2066        case 'D': /* Collision case D. */
2067                retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands,
2068                                              new_asoc);
2069                break;
2070
2071        default: /* Discard packet for all others. */
2072                retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2073                break;
2074        }
2075
2076        /* Delete the tempory new association. */
2077        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
2078        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
2079
2080        /* Restore association pointer to provide SCTP command interpeter
2081         * with a valid context in case it needs to manipulate
2082         * the queues */
2083        sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
2084                         SCTP_ASOC((struct sctp_association *)asoc));
2085
2086        return retval;
2087
2088nomem:
2089        return SCTP_DISPOSITION_NOMEM;
2090}
2091
2092/*
2093 * Process an ABORT.  (SHUTDOWN-PENDING state)
2094 *
2095 * See sctp_sf_do_9_1_abort().
2096 */
2097sctp_disposition_t sctp_sf_shutdown_pending_abort(
2098        struct net *net,
2099        const struct sctp_endpoint *ep,
2100        const struct sctp_association *asoc,
2101        const sctp_subtype_t type,
2102        void *arg,
2103        sctp_cmd_seq_t *commands)
2104{
2105        struct sctp_chunk *chunk = arg;
2106
2107        if (!sctp_vtag_verify_either(chunk, asoc))
2108                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2109
2110        /* Make sure that the ABORT chunk has a valid length.
2111         * Since this is an ABORT chunk, we have to discard it
2112         * because of the following text:
2113         * RFC 2960, Section 3.3.7
2114         *    If an endpoint receives an ABORT with a format error or for an
2115         *    association that doesn't exist, it MUST silently discard it.
2116         * Because the length is "invalid", we can't really discard just
2117         * as we do not know its true length.  So, to be safe, discard the
2118         * packet.
2119         */
2120        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2121                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2122
2123        /* ADD-IP: Special case for ABORT chunks
2124         * F4)  One special consideration is that ABORT Chunks arriving
2125         * destined to the IP address being deleted MUST be
2126         * ignored (see Section 5.3.1 for further details).
2127         */
2128        if (SCTP_ADDR_DEL ==
2129                    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2130                return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2131
2132        return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2133}
2134
2135/*
2136 * Process an ABORT.  (SHUTDOWN-SENT state)
2137 *
2138 * See sctp_sf_do_9_1_abort().
2139 */
2140sctp_disposition_t sctp_sf_shutdown_sent_abort(struct net *net,
2141                                        const struct sctp_endpoint *ep,
2142                                        const struct sctp_association *asoc,
2143                                        const sctp_subtype_t type,
2144                                        void *arg,
2145                                        sctp_cmd_seq_t *commands)
2146{
2147        struct sctp_chunk *chunk = arg;
2148
2149        if (!sctp_vtag_verify_either(chunk, asoc))
2150                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2151
2152        /* Make sure that the ABORT chunk has a valid length.
2153         * Since this is an ABORT chunk, we have to discard it
2154         * because of the following text:
2155         * RFC 2960, Section 3.3.7
2156         *    If an endpoint receives an ABORT with a format error or for an
2157         *    association that doesn't exist, it MUST silently discard it.
2158         * Because the length is "invalid", we can't really discard just
2159         * as we do not know its true length.  So, to be safe, discard the
2160         * packet.
2161         */
2162        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2163                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2164
2165        /* ADD-IP: Special case for ABORT chunks
2166         * F4)  One special consideration is that ABORT Chunks arriving
2167         * destined to the IP address being deleted MUST be
2168         * ignored (see Section 5.3.1 for further details).
2169         */
2170        if (SCTP_ADDR_DEL ==
2171                    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2172                return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2173
2174        /* Stop the T2-shutdown timer. */
2175        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2176                        SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2177
2178        /* Stop the T5-shutdown guard timer.  */
2179        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2180                        SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
2181
2182        return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2183}
2184
2185/*
2186 * Process an ABORT.  (SHUTDOWN-ACK-SENT state)
2187 *
2188 * See sctp_sf_do_9_1_abort().
2189 */
2190sctp_disposition_t sctp_sf_shutdown_ack_sent_abort(
2191        struct net *net,
2192        const struct sctp_endpoint *ep,
2193        const struct sctp_association *asoc,
2194        const sctp_subtype_t type,
2195        void *arg,
2196        sctp_cmd_seq_t *commands)
2197{
2198        /* The same T2 timer, so we should be able to use
2199         * common function with the SHUTDOWN-SENT state.
2200         */
2201        return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands);
2202}
2203
2204/*
2205 * Handle an Error received in COOKIE_ECHOED state.
2206 *
2207 * Only handle the error type of stale COOKIE Error, the other errors will
2208 * be ignored.
2209 *
2210 * Inputs
2211 * (endpoint, asoc, chunk)
2212 *
2213 * Outputs
2214 * (asoc, reply_msg, msg_up, timers, counters)
2215 *
2216 * The return value is the disposition of the chunk.
2217 */
2218sctp_disposition_t sctp_sf_cookie_echoed_err(struct net *net,
2219                                        const struct sctp_endpoint *ep,
2220                                        const struct sctp_association *asoc,
2221                                        const sctp_subtype_t type,
2222                                        void *arg,
2223                                        sctp_cmd_seq_t *commands)
2224{
2225        struct sctp_chunk *chunk = arg;
2226        sctp_errhdr_t *err;
2227
2228        if (!sctp_vtag_verify(chunk, asoc))
2229                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2230
2231        /* Make sure that the ERROR chunk has a valid length.
2232         * The parameter walking depends on this as well.
2233         */
2234        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
2235                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2236                                                  commands);
2237
2238        /* Process the error here */
2239        /* FUTURE FIXME:  When PR-SCTP related and other optional
2240         * parms are emitted, this will have to change to handle multiple
2241         * errors.
2242         */
2243        sctp_walk_errors(err, chunk->chunk_hdr) {
2244                if (SCTP_ERROR_STALE_COOKIE == err->cause)
2245                        return sctp_sf_do_5_2_6_stale(net, ep, asoc, type,
2246                                                        arg, commands);
2247        }
2248
2249        /* It is possible to have malformed error causes, and that
2250         * will cause us to end the walk early.  However, since
2251         * we are discarding the packet, there should be no adverse
2252         * affects.
2253         */
2254        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2255}
2256
2257/*
2258 * Handle a Stale COOKIE Error
2259 *
2260 * Section: 5.2.6 Handle Stale COOKIE Error
2261 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2262 * one of the following three alternatives.
2263 * ...
2264 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2265 *    Preservative parameter requesting an extension to the lifetime of
2266 *    the State Cookie. When calculating the time extension, an
2267 *    implementation SHOULD use the RTT information measured based on the
2268 *    previous COOKIE ECHO / ERROR exchange, and should add no more
2269 *    than 1 second beyond the measured RTT, due to long State Cookie
2270 *    lifetimes making the endpoint more subject to a replay attack.
2271 *
2272 * Verification Tag:  Not explicit, but safe to ignore.
2273 *
2274 * Inputs
2275 * (endpoint, asoc, chunk)
2276 *
2277 * Outputs
2278 * (asoc, reply_msg, msg_up, timers, counters)
2279 *
2280 * The return value is the disposition of the chunk.
2281 */
2282static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net,
2283                                                 const struct sctp_endpoint *ep,
2284                                                 const struct sctp_association *asoc,
2285                                                 const sctp_subtype_t type,
2286                                                 void *arg,
2287                                                 sctp_cmd_seq_t *commands)
2288{
2289        struct sctp_chunk *chunk = arg;
2290        time_t stale;
2291        sctp_cookie_preserve_param_t bht;
2292        sctp_errhdr_t *err;
2293        struct sctp_chunk *reply;
2294        struct sctp_bind_addr *bp;
2295        int attempts = asoc->init_err_counter + 1;
2296
2297        if (attempts > asoc->max_init_attempts) {
2298                sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2299                                SCTP_ERROR(ETIMEDOUT));
2300                sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2301                                SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2302                return SCTP_DISPOSITION_DELETE_TCB;
2303        }
2304
2305        err = (sctp_errhdr_t *)(chunk->skb->data);
2306
2307        /* When calculating the time extension, an implementation
2308         * SHOULD use the RTT information measured based on the
2309         * previous COOKIE ECHO / ERROR exchange, and should add no
2310         * more than 1 second beyond the measured RTT, due to long
2311         * State Cookie lifetimes making the endpoint more subject to
2312         * a replay attack.
2313         * Measure of Staleness's unit is usec. (1/1000000 sec)
2314         * Suggested Cookie Life-span Increment's unit is msec.
2315         * (1/1000 sec)
2316         * In general, if you use the suggested cookie life, the value
2317         * found in the field of measure of staleness should be doubled
2318         * to give ample time to retransmit the new cookie and thus
2319         * yield a higher probability of success on the reattempt.
2320         */
2321        stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t)));
2322        stale = (stale * 2) / 1000;
2323
2324        bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2325        bht.param_hdr.length = htons(sizeof(bht));
2326        bht.lifespan_increment = htonl(stale);
2327
2328        /* Build that new INIT chunk.  */
2329        bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2330        reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2331        if (!reply)
2332                goto nomem;
2333
2334        sctp_addto_chunk(reply, sizeof(bht), &bht);
2335
2336        /* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2337        sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2338
2339        /* Stop pending T3-rtx and heartbeat timers */
2340        sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2341        sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2342
2343        /* Delete non-primary peer ip addresses since we are transitioning
2344         * back to the COOKIE-WAIT state
2345         */
2346        sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2347
2348        /* If we've sent any data bundled with COOKIE-ECHO we will need to
2349         * resend
2350         */
2351        sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
2352                        SCTP_TRANSPORT(asoc->peer.primary_path));
2353
2354        /* Cast away the const modifier, as we want to just
2355         * rerun it through as a sideffect.
2356         */
2357        sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2358
2359        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2360                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2361        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2362                        SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2363        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2364                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2365
2366        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2367
2368        return SCTP_DISPOSITION_CONSUME;
2369
2370nomem:
2371        return SCTP_DISPOSITION_NOMEM;
2372}
2373
2374/*
2375 * Process an ABORT.
2376 *
2377 * Section: 9.1
2378 * After checking the Verification Tag, the receiving endpoint shall
2379 * remove the association from its record, and shall report the
2380 * termination to its upper layer.
2381 *
2382 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
2383 * B) Rules for packet carrying ABORT:
2384 *
2385 *  - The endpoint shall always fill in the Verification Tag field of the
2386 *    outbound packet with the destination endpoint's tag value if it
2387 *    is known.
2388 *
2389 *  - If the ABORT is sent in response to an OOTB packet, the endpoint
2390 *    MUST follow the procedure described in Section 8.4.
2391 *
2392 *  - The receiver MUST accept the packet if the Verification Tag
2393 *    matches either its own tag, OR the tag of its peer. Otherwise, the
2394 *    receiver MUST silently discard the packet and take no further
2395 *    action.
2396 *
2397 * Inputs
2398 * (endpoint, asoc, chunk)
2399 *
2400 * Outputs
2401 * (asoc, reply_msg, msg_up, timers, counters)
2402 *
2403 * The return value is the disposition of the chunk.
2404 */
2405sctp_disposition_t sctp_sf_do_9_1_abort(struct net *net,
2406                                        const struct sctp_endpoint *ep,
2407                                        const struct sctp_association *asoc,
2408                                        const sctp_subtype_t type,
2409                                        void *arg,
2410                                        sctp_cmd_seq_t *commands)
2411{
2412        struct sctp_chunk *chunk = arg;
2413
2414        if (!sctp_vtag_verify_either(chunk, asoc))
2415                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2416
2417        /* Make sure that the ABORT chunk has a valid length.
2418         * Since this is an ABORT chunk, we have to discard it
2419         * because of the following text:
2420         * RFC 2960, Section 3.3.7
2421         *    If an endpoint receives an ABORT with a format error or for an
2422         *    association that doesn't exist, it MUST silently discard it.
2423         * Because the length is "invalid", we can't really discard just
2424         * as we do not know its true length.  So, to be safe, discard the
2425         * packet.
2426         */
2427        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2428                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2429
2430        /* ADD-IP: Special case for ABORT chunks
2431         * F4)  One special consideration is that ABORT Chunks arriving
2432         * destined to the IP address being deleted MUST be
2433         * ignored (see Section 5.3.1 for further details).
2434         */
2435        if (SCTP_ADDR_DEL ==
2436                    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2437                return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2438
2439        return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2440}
2441
2442static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net,
2443                                        const struct sctp_endpoint *ep,
2444                                        const struct sctp_association *asoc,
2445                                        const sctp_subtype_t type,
2446                                        void *arg,
2447                                        sctp_cmd_seq_t *commands)
2448{
2449        struct sctp_chunk *chunk = arg;
2450        unsigned int len;
2451        __be16 error = SCTP_ERROR_NO_ERROR;
2452
2453        /* See if we have an error cause code in the chunk.  */
2454        len = ntohs(chunk->chunk_hdr->length);
2455        if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) {
2456
2457                sctp_errhdr_t *err;
2458                sctp_walk_errors(err, chunk->chunk_hdr);
2459                if ((void *)err != (void *)chunk->chunk_end)
2460                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2461
2462                error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2463        }
2464
2465        sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
2466        /* ASSOC_FAILED will DELETE_TCB. */
2467        sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
2468        SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2469        SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
2470
2471        return SCTP_DISPOSITION_ABORT;
2472}
2473
2474/*
2475 * Process an ABORT.  (COOKIE-WAIT state)
2476 *
2477 * See sctp_sf_do_9_1_abort() above.
2478 */
2479sctp_disposition_t sctp_sf_cookie_wait_abort(struct net *net,
2480                                     const struct sctp_endpoint *ep,
2481                                     const struct sctp_association *asoc,
2482                                     const sctp_subtype_t type,
2483                                     void *arg,
2484                                     sctp_cmd_seq_t *commands)
2485{
2486        struct sctp_chunk *chunk = arg;
2487        unsigned int len;
2488        __be16 error = SCTP_ERROR_NO_ERROR;
2489
2490        if (!sctp_vtag_verify_either(chunk, asoc))
2491                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2492
2493        /* Make sure that the ABORT chunk has a valid length.
2494         * Since this is an ABORT chunk, we have to discard it
2495         * because of the following text:
2496         * RFC 2960, Section 3.3.7
2497         *    If an endpoint receives an ABORT with a format error or for an
2498         *    association that doesn't exist, it MUST silently discard it.
2499         * Because the length is "invalid", we can't really discard just
2500         * as we do not know its true length.  So, to be safe, discard the
2501         * packet.
2502         */
2503        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2504                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2505
2506        /* See if we have an error cause code in the chunk.  */
2507        len = ntohs(chunk->chunk_hdr->length);
2508        if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2509                error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2510
2511        return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc,
2512                                      chunk->transport);
2513}
2514
2515/*
2516 * Process an incoming ICMP as an ABORT.  (COOKIE-WAIT state)
2517 */
2518sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(struct net *net,
2519                                        const struct sctp_endpoint *ep,
2520                                        const struct sctp_association *asoc,
2521                                        const sctp_subtype_t type,
2522                                        void *arg,
2523                                        sctp_cmd_seq_t *commands)
2524{
2525        return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR,
2526                                      ENOPROTOOPT, asoc,
2527                                      (struct sctp_transport *)arg);
2528}
2529
2530/*
2531 * Process an ABORT.  (COOKIE-ECHOED state)
2532 */
2533sctp_disposition_t sctp_sf_cookie_echoed_abort(struct net *net,
2534                                               const struct sctp_endpoint *ep,
2535                                               const struct sctp_association *asoc,
2536                                               const sctp_subtype_t type,
2537                                               void *arg,
2538                                               sctp_cmd_seq_t *commands)
2539{
2540        /* There is a single T1 timer, so we should be able to use
2541         * common function with the COOKIE-WAIT state.
2542         */
2543        return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands);
2544}
2545
2546/*
2547 * Stop T1 timer and abort association with "INIT failed".
2548 *
2549 * This is common code called by several sctp_sf_*_abort() functions above.
2550 */
2551static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net,
2552                                           sctp_cmd_seq_t *commands,
2553                                           __be16 error, int sk_err,
2554                                           const struct sctp_association *asoc,
2555                                           struct sctp_transport *transport)
2556{
2557        SCTP_DEBUG_PRINTK("ABORT received (INIT).\n");
2558        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2559                        SCTP_STATE(SCTP_STATE_CLOSED));
2560        SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2561        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2562                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2563        sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
2564        /* CMD_INIT_FAILED will DELETE_TCB. */
2565        sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2566                        SCTP_PERR(error));
2567        return SCTP_DISPOSITION_ABORT;
2568}
2569
2570/*
2571 * sctp_sf_do_9_2_shut
2572 *
2573 * Section: 9.2
2574 * Upon the reception of the SHUTDOWN, the peer endpoint shall
2575 *  - enter the SHUTDOWN-RECEIVED state,
2576 *
2577 *  - stop accepting new data from its SCTP user
2578 *
2579 *  - verify, by checking the Cumulative TSN Ack field of the chunk,
2580 *    that all its outstanding DATA chunks have been received by the
2581 *    SHUTDOWN sender.
2582 *
2583 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
2584 * send a SHUTDOWN in response to a ULP request. And should discard
2585 * subsequent SHUTDOWN chunks.
2586 *
2587 * If there are still outstanding DATA chunks left, the SHUTDOWN
2588 * receiver shall continue to follow normal data transmission
2589 * procedures defined in Section 6 until all outstanding DATA chunks
2590 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
2591 * new data from its SCTP user.
2592 *
2593 * Verification Tag:  8.5 Verification Tag [Normal verification]
2594 *
2595 * Inputs
2596 * (endpoint, asoc, chunk)
2597 *
2598 * Outputs
2599 * (asoc, reply_msg, msg_up, timers, counters)
2600 *
2601 * The return value is the disposition of the chunk.
2602 */
2603sctp_disposition_t sctp_sf_do_9_2_shutdown(struct net *net,
2604                                           const struct sctp_endpoint *ep,
2605                                           const struct sctp_association *asoc,
2606                                           const sctp_subtype_t type,
2607                                           void *arg,
2608                                           sctp_cmd_seq_t *commands)
2609{
2610        struct sctp_chunk *chunk = arg;
2611        sctp_shutdownhdr_t *sdh;
2612        sctp_disposition_t disposition;
2613        struct sctp_ulpevent *ev;
2614        __u32 ctsn;
2615
2616        if (!sctp_vtag_verify(chunk, asoc))
2617                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2618
2619        /* Make sure that the SHUTDOWN chunk has a valid length. */
2620        if (!sctp_chunk_length_valid(chunk,
2621                                      sizeof(struct sctp_shutdown_chunk_t)))
2622                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2623                                                  commands);
2624
2625        /* Convert the elaborate header.  */
2626        sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
2627        skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t));
2628        chunk->subh.shutdown_hdr = sdh;
2629        ctsn = ntohl(sdh->cum_tsn_ack);
2630
2631        if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2632                SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
2633                SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
2634                return SCTP_DISPOSITION_DISCARD;
2635        }
2636
2637        /* If Cumulative TSN Ack beyond the max tsn currently
2638         * send, terminating the association and respond to the
2639         * sender with an ABORT.
2640         */
2641        if (!TSN_lt(ctsn, asoc->next_tsn))
2642                return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2643
2644        /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
2645         * When a peer sends a SHUTDOWN, SCTP delivers this notification to
2646         * inform the application that it should cease sending data.
2647         */
2648        ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2649        if (!ev) {
2650                disposition = SCTP_DISPOSITION_NOMEM;
2651                goto out;
2652        }
2653        sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2654
2655        /* Upon the reception of the SHUTDOWN, the peer endpoint shall
2656         *  - enter the SHUTDOWN-RECEIVED state,
2657         *  - stop accepting new data from its SCTP user
2658         *
2659         * [This is implicit in the new state.]
2660         */
2661        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2662                        SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2663        disposition = SCTP_DISPOSITION_CONSUME;
2664
2665        if (sctp_outq_is_empty(&asoc->outqueue)) {
2666                disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type,
2667                                                          arg, commands);
2668        }
2669
2670        if (SCTP_DISPOSITION_NOMEM == disposition)
2671                goto out;
2672
2673        /*  - verify, by checking the Cumulative TSN Ack field of the
2674         *    chunk, that all its outstanding DATA chunks have been
2675         *    received by the SHUTDOWN sender.
2676         */
2677        sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2678                        SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2679
2680out:
2681        return disposition;
2682}
2683
2684/*
2685 * sctp_sf_do_9_2_shut_ctsn
2686 *
2687 * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
2688 * it MUST NOT send a SHUTDOWN in response to a ULP request.
2689 * The Cumulative TSN Ack of the received SHUTDOWN chunk
2690 * MUST be processed.
2691 */
2692sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(struct net *net,
2693                                           const struct sctp_endpoint *ep,
2694                                           const struct sctp_association *asoc,
2695                                           const sctp_subtype_t type,
2696                                           void *arg,
2697                                           sctp_cmd_seq_t *commands)
2698{
2699        struct sctp_chunk *chunk = arg;
2700        sctp_shutdownhdr_t *sdh;
2701        __u32 ctsn;
2702
2703        if (!sctp_vtag_verify(chunk, asoc))
2704                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2705
2706        /* Make sure that the SHUTDOWN chunk has a valid length. */
2707        if (!sctp_chunk_length_valid(chunk,
2708                                      sizeof(struct sctp_shutdown_chunk_t)))
2709                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2710                                                  commands);
2711
2712        sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
2713        ctsn = ntohl(sdh->cum_tsn_ack);
2714
2715        if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2716                SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
2717                SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
2718                return SCTP_DISPOSITION_DISCARD;
2719        }
2720
2721        /* If Cumulative TSN Ack beyond the max tsn currently
2722         * send, terminating the association and respond to the
2723         * sender with an ABORT.
2724         */
2725        if (!TSN_lt(ctsn, asoc->next_tsn))
2726                return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2727
2728        /* verify, by checking the Cumulative TSN Ack field of the
2729         * chunk, that all its outstanding DATA chunks have been
2730         * received by the SHUTDOWN sender.
2731         */
2732        sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2733                        SCTP_BE32(sdh->cum_tsn_ack));
2734
2735        return SCTP_DISPOSITION_CONSUME;
2736}
2737
2738/* RFC 2960 9.2
2739 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
2740 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
2741 * transport addresses (either in the IP addresses or in the INIT chunk)
2742 * that belong to this association, it should discard the INIT chunk and
2743 * retransmit the SHUTDOWN ACK chunk.
2744 */
2745sctp_disposition_t sctp_sf_do_9_2_reshutack(struct net *net,
2746                                    const struct sctp_endpoint *ep,
2747                                    const struct sctp_association *asoc,
2748                                    const sctp_subtype_t type,
2749                                    void *arg,
2750                                    sctp_cmd_seq_t *commands)
2751{
2752        struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
2753        struct sctp_chunk *reply;
2754
2755        /* Make sure that the chunk has a valid length */
2756        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
2757                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2758                                                  commands);
2759
2760        /* Since we are not going to really process this INIT, there
2761         * is no point in verifying chunk boundries.  Just generate
2762         * the SHUTDOWN ACK.
2763         */
2764        reply = sctp_make_shutdown_ack(asoc, chunk);
2765        if (NULL == reply)
2766                goto nomem;
2767
2768        /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
2769         * the T2-SHUTDOWN timer.
2770         */
2771        sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
2772
2773        /* and restart the T2-shutdown timer. */
2774        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2775                        SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2776
2777        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2778
2779        return SCTP_DISPOSITION_CONSUME;
2780nomem:
2781        return SCTP_DISPOSITION_NOMEM;
2782}
2783
2784/*
2785 * sctp_sf_do_ecn_cwr
2786 *
2787 * Section:  Appendix A: Explicit Congestion Notification
2788 *
2789 * CWR:
2790 *
2791 * RFC 2481 details a specific bit for a sender to send in the header of
2792 * its next outbound TCP segment to indicate to its peer that it has
2793 * reduced its congestion window.  This is termed the CWR bit.  For
2794 * SCTP the same indication is made by including the CWR chunk.
2795 * This chunk contains one data element, i.e. the TSN number that
2796 * was sent in the ECNE chunk.  This element represents the lowest
2797 * TSN number in the datagram that was originally marked with the
2798 * CE bit.
2799 *
2800 * Verification Tag: 8.5 Verification Tag [Normal verification]
2801 * Inputs
2802 * (endpoint, asoc, chunk)
2803 *
2804 * Outputs
2805 * (asoc, reply_msg, msg_up, timers, counters)
2806 *
2807 * The return value is the disposition of the chunk.
2808 */
2809sctp_disposition_t sctp_sf_do_ecn_cwr(struct net *net,
2810                                      const struct sctp_endpoint *ep,
2811                                      const struct sctp_association *asoc,
2812                                      const sctp_subtype_t type,
2813                                      void *arg,
2814                                      sctp_cmd_seq_t *commands)
2815{
2816        sctp_cwrhdr_t *cwr;
2817        struct sctp_chunk *chunk = arg;
2818        u32 lowest_tsn;
2819
2820        if (!sctp_vtag_verify(chunk, asoc))
2821                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2822
2823        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2824                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2825                                                  commands);
2826
2827        cwr = (sctp_cwrhdr_t *) chunk->skb->data;
2828        skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t));
2829
2830        lowest_tsn = ntohl(cwr->lowest_tsn);
2831
2832        /* Does this CWR ack the last sent congestion notification? */
2833        if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
2834                /* Stop sending ECNE. */
2835                sctp_add_cmd_sf(commands,
2836                                SCTP_CMD_ECN_CWR,
2837                                SCTP_U32(lowest_tsn));
2838        }
2839        return SCTP_DISPOSITION_CONSUME;
2840}
2841
2842/*
2843 * sctp_sf_do_ecne
2844 *
2845 * Section:  Appendix A: Explicit Congestion Notification
2846 *
2847 * ECN-Echo
2848 *
2849 * RFC 2481 details a specific bit for a receiver to send back in its
2850 * TCP acknowledgements to notify the sender of the Congestion
2851 * Experienced (CE) bit having arrived from the network.  For SCTP this
2852 * same indication is made by including the ECNE chunk.  This chunk
2853 * contains one data element, i.e. the lowest TSN associated with the IP
2854 * datagram marked with the CE bit.....
2855 *
2856 * Verification Tag: 8.5 Verification Tag [Normal verification]
2857 * Inputs
2858 * (endpoint, asoc, chunk)
2859 *
2860 * Outputs
2861 * (asoc, reply_msg, msg_up, timers, counters)
2862 *
2863 * The return value is the disposition of the chunk.
2864 */
2865sctp_disposition_t sctp_sf_do_ecne(struct net *net,
2866                                   const struct sctp_endpoint *ep,
2867                                   const struct sctp_association *asoc,
2868                                   const sctp_subtype_t type,
2869                                   void *arg,
2870                                   sctp_cmd_seq_t *commands)
2871{
2872        sctp_ecnehdr_t *ecne;
2873        struct sctp_chunk *chunk = arg;
2874
2875        if (!sctp_vtag_verify(chunk, asoc))
2876                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2877
2878        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2879                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2880                                                  commands);
2881
2882        ecne = (sctp_ecnehdr_t *) chunk->skb->data;
2883        skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t));
2884
2885        /* If this is a newer ECNE than the last CWR packet we sent out */
2886        sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
2887                        SCTP_U32(ntohl(ecne->lowest_tsn)));
2888
2889        return SCTP_DISPOSITION_CONSUME;
2890}
2891
2892/*
2893 * Section: 6.2  Acknowledgement on Reception of DATA Chunks
2894 *
2895 * The SCTP endpoint MUST always acknowledge the reception of each valid
2896 * DATA chunk.
2897 *
2898 * The guidelines on delayed acknowledgement algorithm specified in
2899 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
2900 * acknowledgement SHOULD be generated for at least every second packet
2901 * (not every second DATA chunk) received, and SHOULD be generated within
2902 * 200 ms of the arrival of any unacknowledged DATA chunk. In some
2903 * situations it may be beneficial for an SCTP transmitter to be more
2904 * conservative than the algorithms detailed in this document allow.
2905 * However, an SCTP transmitter MUST NOT be more aggressive than the
2906 * following algorithms allow.
2907 *
2908 * A SCTP receiver MUST NOT generate more than one SACK for every
2909 * incoming packet, other than to update the offered window as the
2910 * receiving application consumes new data.
2911 *
2912 * Verification Tag:  8.5 Verification Tag [Normal verification]
2913 *
2914 * Inputs
2915 * (endpoint, asoc, chunk)
2916 *
2917 * Outputs
2918 * (asoc, reply_msg, msg_up, timers, counters)
2919 *
2920 * The return value is the disposition of the chunk.
2921 */
2922sctp_disposition_t sctp_sf_eat_data_6_2(struct net *net,
2923                                        const struct sctp_endpoint *ep,
2924                                        const struct sctp_association *asoc,
2925                                        const sctp_subtype_t type,
2926                                        void *arg,
2927                                        sctp_cmd_seq_t *commands)
2928{
2929        struct sctp_chunk *chunk = arg;
2930        sctp_arg_t force = SCTP_NOFORCE();
2931        int error;
2932
2933        if (!sctp_vtag_verify(chunk, asoc)) {
2934                sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
2935                                SCTP_NULL());
2936                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2937        }
2938
2939        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
2940                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2941                                                  commands);
2942
2943        error = sctp_eat_data(asoc, chunk, commands );
2944        switch (error) {
2945        case SCTP_IERROR_NO_ERROR:
2946                break;
2947        case SCTP_IERROR_HIGH_TSN:
2948        case SCTP_IERROR_BAD_STREAM:
2949                SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2950                goto discard_noforce;
2951        case SCTP_IERROR_DUP_TSN:
2952        case SCTP_IERROR_IGNORE_TSN:
2953                SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2954                goto discard_force;
2955        case SCTP_IERROR_NO_DATA:
2956                goto consume;
2957        case SCTP_IERROR_PROTO_VIOLATION:
2958                return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
2959                        (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t));
2960        default:
2961                BUG();
2962        }
2963
2964        if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM)
2965                force = SCTP_FORCE();
2966
2967        if (asoc->autoclose) {
2968                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2969                                SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
2970        }
2971
2972        /* If this is the last chunk in a packet, we need to count it
2973         * toward sack generation.  Note that we need to SACK every
2974         * OTHER packet containing data chunks, EVEN IF WE DISCARD
2975         * THEM.  We elect to NOT generate SACK's if the chunk fails
2976         * the verification tag test.
2977         *
2978         * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
2979         *
2980         * The SCTP endpoint MUST always acknowledge the reception of
2981         * each valid DATA chunk.
2982         *
2983         * The guidelines on delayed acknowledgement algorithm
2984         * specified in  Section 4.2 of [RFC2581] SHOULD be followed.
2985         * Specifically, an acknowledgement SHOULD be generated for at
2986         * least every second packet (not every second DATA chunk)
2987         * received, and SHOULD be generated within 200 ms of the
2988         * arrival of any unacknowledged DATA chunk.  In some
2989         * situations it may be beneficial for an SCTP transmitter to
2990         * be more conservative than the algorithms detailed in this
2991         * document allow. However, an SCTP transmitter MUST NOT be
2992         * more aggressive than the following algorithms allow.
2993         */
2994        if (chunk->end_of_packet)
2995                sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
2996
2997        return SCTP_DISPOSITION_CONSUME;
2998
2999discard_force:
3000        /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3001         *
3002         * When a packet arrives with duplicate DATA chunk(s) and with
3003         * no new DATA chunk(s), the endpoint MUST immediately send a
3004         * SACK with no delay.  If a packet arrives with duplicate
3005         * DATA chunk(s) bundled with new DATA chunks, the endpoint
3006         * MAY immediately send a SACK.  Normally receipt of duplicate
3007         * DATA chunks will occur when the original SACK chunk was lost
3008         * and the peer's RTO has expired.  The duplicate TSN number(s)
3009         * SHOULD be reported in the SACK as duplicate.
3010         */
3011        /* In our case, we split the MAY SACK advice up whether or not
3012         * the last chunk is a duplicate.'
3013         */
3014        if (chunk->end_of_packet)
3015                sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3016        return SCTP_DISPOSITION_DISCARD;
3017
3018discard_noforce:
3019        if (chunk->end_of_packet)
3020                sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3021
3022        return SCTP_DISPOSITION_DISCARD;
3023consume:
3024        return SCTP_DISPOSITION_CONSUME;
3025
3026}
3027
3028/*
3029 * sctp_sf_eat_data_fast_4_4
3030 *
3031 * Section: 4 (4)
3032 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
3033 *    DATA chunks without delay.
3034 *
3035 * Verification Tag:  8.5 Verification Tag [Normal verification]
3036 * Inputs
3037 * (endpoint, asoc, chunk)
3038 *
3039 * Outputs
3040 * (asoc, reply_msg, msg_up, timers, counters)
3041 *
3042 * The return value is the disposition of the chunk.
3043 */
3044sctp_disposition_t sctp_sf_eat_data_fast_4_4(struct net *net,
3045                                     const struct sctp_endpoint *ep,
3046                                     const struct sctp_association *asoc,
3047                                     const sctp_subtype_t type,
3048                                     void *arg,
3049                                     sctp_cmd_seq_t *commands)
3050{
3051        struct sctp_chunk *chunk = arg;
3052        int error;
3053
3054        if (!sctp_vtag_verify(chunk, asoc)) {
3055                sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3056                                SCTP_NULL());
3057                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3058        }
3059
3060        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
3061                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3062                                                  commands);
3063
3064        error = sctp_eat_data(asoc, chunk, commands );
3065        switch (error) {
3066        case SCTP_IERROR_NO_ERROR:
3067        case SCTP_IERROR_HIGH_TSN:
3068        case SCTP_IERROR_DUP_TSN:
3069        case SCTP_IERROR_IGNORE_TSN:
3070        case SCTP_IERROR_BAD_STREAM:
3071                break;
3072        case SCTP_IERROR_NO_DATA:
3073                goto consume;
3074        case SCTP_IERROR_PROTO_VIOLATION:
3075                return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3076                        (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t));
3077        default:
3078                BUG();
3079        }
3080
3081        /* Go a head and force a SACK, since we are shutting down. */
3082
3083        /* Implementor's Guide.
3084         *
3085         * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3086         * respond to each received packet containing one or more DATA chunk(s)
3087         * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3088         */
3089        if (chunk->end_of_packet) {
3090                /* We must delay the chunk creation since the cumulative
3091                 * TSN has not been updated yet.
3092                 */
3093                sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3094                sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3095                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3096                                SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3097        }
3098
3099consume:
3100        return SCTP_DISPOSITION_CONSUME;
3101}
3102
3103/*
3104 * Section: 6.2  Processing a Received SACK
3105 * D) Any time a SACK arrives, the endpoint performs the following:
3106 *
3107 *     i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
3108 *     then drop the SACK.   Since Cumulative TSN Ack is monotonically
3109 *     increasing, a SACK whose Cumulative TSN Ack is less than the
3110 *     Cumulative TSN Ack Point indicates an out-of-order SACK.
3111 *
3112 *     ii) Set rwnd equal to the newly received a_rwnd minus the number
3113 *     of bytes still outstanding after processing the Cumulative TSN Ack
3114 *     and the Gap Ack Blocks.
3115 *
3116 *     iii) If the SACK is missing a TSN that was previously
3117 *     acknowledged via a Gap Ack Block (e.g., the data receiver
3118 *     reneged on the data), then mark the corresponding DATA chunk
3119 *     as available for retransmit:  Mark it as missing for fast
3120 *     retransmit as described in Section 7.2.4 and if no retransmit
3121 *     timer is running for the destination address to which the DATA
3122 *     chunk was originally transmitted, then T3-rtx is started for
3123 *     that destination address.
3124 *
3125 * Verification Tag:  8.5 Verification Tag [Normal verification]
3126 *
3127 * Inputs
3128 * (endpoint, asoc, chunk)
3129 *
3130 * Outputs
3131 * (asoc, reply_msg, msg_up, timers, counters)
3132 *
3133 * The return value is the disposition of the chunk.
3134 */
3135sctp_disposition_t sctp_sf_eat_sack_6_2(struct net *net,
3136                                        const struct sctp_endpoint *ep,
3137                                        const struct sctp_association *asoc,
3138                                        const sctp_subtype_t type,
3139                                        void *arg,
3140                                        sctp_cmd_seq_t *commands)
3141{
3142        struct sctp_chunk *chunk = arg;
3143        sctp_sackhdr_t *sackh;
3144        __u32 ctsn;
3145
3146        if (!sctp_vtag_verify(chunk, asoc))
3147                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3148
3149        /* Make sure that the SACK chunk has a valid length. */
3150        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t)))
3151                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3152                                                  commands);
3153
3154        /* Pull the SACK chunk from the data buffer */
3155        sackh = sctp_sm_pull_sack(chunk);
3156        /* Was this a bogus SACK? */
3157        if (!sackh)
3158                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3159        chunk->subh.sack_hdr = sackh;
3160        ctsn = ntohl(sackh->cum_tsn_ack);
3161
3162        /* i) If Cumulative TSN Ack is less than the Cumulative TSN
3163         *     Ack Point, then drop the SACK.  Since Cumulative TSN
3164         *     Ack is monotonically increasing, a SACK whose
3165         *     Cumulative TSN Ack is less than the Cumulative TSN Ack
3166         *     Point indicates an out-of-order SACK.
3167         */
3168        if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
3169                SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
3170                SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
3171                return SCTP_DISPOSITION_DISCARD;
3172        }
3173
3174        /* If Cumulative TSN Ack beyond the max tsn currently
3175         * send, terminating the association and respond to the
3176         * sender with an ABORT.
3177         */
3178        if (!TSN_lt(ctsn, asoc->next_tsn))
3179                return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
3180
3181        /* Return this SACK for further processing.  */
3182        sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk));
3183
3184        /* Note: We do the rest of the work on the PROCESS_SACK
3185         * sideeffect.
3186         */
3187        return SCTP_DISPOSITION_CONSUME;
3188}
3189
3190/*
3191 * Generate an ABORT in response to a packet.
3192 *
3193 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
3194 *
3195 * 8) The receiver should respond to the sender of the OOTB packet with
3196 *    an ABORT.  When sending the ABORT, the receiver of the OOTB packet
3197 *    MUST fill in the Verification Tag field of the outbound packet
3198 *    with the value found in the Verification Tag field of the OOTB
3199 *    packet and set the T-bit in the Chunk Flags to indicate that the
3200 *    Verification Tag is reflected.  After sending this ABORT, the
3201 *    receiver of the OOTB packet shall discard the OOTB packet and take
3202 *    no further action.
3203 *
3204 * Verification Tag:
3205 *
3206 * The return value is the disposition of the chunk.
3207*/
3208static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net,
3209                                        const struct sctp_endpoint *ep,
3210                                        const struct sctp_association *asoc,
3211                                        const sctp_subtype_t type,
3212                                        void *arg,
3213                                        sctp_cmd_seq_t *commands)
3214{
3215        struct sctp_packet *packet = NULL;
3216        struct sctp_chunk *chunk = arg;
3217        struct sctp_chunk *abort;
3218
3219        packet = sctp_ootb_pkt_new(net, asoc, chunk);
3220
3221        if (packet) {
3222                /* Make an ABORT. The T bit will be set if the asoc
3223                 * is NULL.
3224                 */
3225                abort = sctp_make_abort(asoc, chunk, 0);
3226                if (!abort) {
3227                        sctp_ootb_pkt_free(packet);
3228                        return SCTP_DISPOSITION_NOMEM;
3229                }
3230
3231                /* Reflect vtag if T-Bit is set */
3232                if (sctp_test_T_bit(abort))
3233                        packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3234
3235                /* Set the skb to the belonging sock for accounting.  */
3236                abort->skb->sk = ep->base.sk;
3237
3238                sctp_packet_append_chunk(packet, abort);
3239
3240                sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3241                                SCTP_PACKET(packet));
3242
3243                SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3244
3245                sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3246                return SCTP_DISPOSITION_CONSUME;
3247        }
3248
3249        return SCTP_DISPOSITION_NOMEM;
3250}
3251
3252/*
3253 * Received an ERROR chunk from peer.  Generate SCTP_REMOTE_ERROR
3254 * event as ULP notification for each cause included in the chunk.
3255 *
3256 * API 5.3.1.3 - SCTP_REMOTE_ERROR
3257 *
3258 * The return value is the disposition of the chunk.
3259*/
3260sctp_disposition_t sctp_sf_operr_notify(struct net *net,
3261                                        const struct sctp_endpoint *ep,
3262                                        const struct sctp_association *asoc,
3263                                        const sctp_subtype_t type,
3264                                        void *arg,
3265                                        sctp_cmd_seq_t *commands)
3266{
3267        struct sctp_chunk *chunk = arg;
3268        sctp_errhdr_t *err;
3269
3270        if (!sctp_vtag_verify(chunk, asoc))
3271                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3272
3273        /* Make sure that the ERROR chunk has a valid length. */
3274        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
3275                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3276                                                  commands);
3277        sctp_walk_errors(err, chunk->chunk_hdr);
3278        if ((void *)err != (void *)chunk->chunk_end)
3279                return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3280                                                  (void *)err, commands);
3281
3282        sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
3283                        SCTP_CHUNK(chunk));
3284
3285        return SCTP_DISPOSITION_CONSUME;
3286}
3287
3288/*
3289 * Process an inbound SHUTDOWN ACK.
3290 *
3291 * From Section 9.2:
3292 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3293 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
3294 * peer, and remove all record of the association.
3295 *
3296 * The return value is the disposition.
3297 */
3298sctp_disposition_t sctp_sf_do_9_2_final(struct net *net,
3299                                        const struct sctp_endpoint *ep,
3300                                        const struct sctp_association *asoc,
3301                                        const sctp_subtype_t type,
3302                                        void *arg,
3303                                        sctp_cmd_seq_t *commands)
3304{
3305        struct sctp_chunk *chunk = arg;
3306        struct sctp_chunk *reply;
3307        struct sctp_ulpevent *ev;
3308
3309        if (!sctp_vtag_verify(chunk, asoc))
3310                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3311
3312        /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3313        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3314                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3315                                                  commands);
3316        /* 10.2 H) SHUTDOWN COMPLETE notification
3317         *
3318         * When SCTP completes the shutdown procedures (section 9.2) this
3319         * notification is passed to the upper layer.
3320         */
3321        ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3322                                             0, 0, 0, NULL, GFP_ATOMIC);
3323        if (!ev)
3324                goto nomem;
3325
3326        /* ...send a SHUTDOWN COMPLETE chunk to its peer, */
3327        reply = sctp_make_shutdown_complete(asoc, chunk);
3328        if (!reply)
3329                goto nomem_chunk;
3330
3331        /* Do all the commands now (after allocation), so that we
3332         * have consistent state if memory allocation failes
3333         */
3334        sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
3335
3336        /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3337         * stop the T2-shutdown timer,
3338         */
3339        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3340                        SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3341
3342        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3343                        SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3344
3345        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3346                        SCTP_STATE(SCTP_STATE_CLOSED));
3347        SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
3348        SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3349        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3350
3351        /* ...and remove all record of the association. */
3352        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
3353        return SCTP_DISPOSITION_DELETE_TCB;
3354
3355nomem_chunk:
3356        sctp_ulpevent_free(ev);
3357nomem:
3358        return SCTP_DISPOSITION_NOMEM;
3359}
3360
3361/*
3362 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
3363 *
3364 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3365 *    respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3366 *    When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3367 *    packet must fill in the Verification Tag field of the outbound
3368 *    packet with the Verification Tag received in the SHUTDOWN ACK and
3369 *    set the T-bit in the Chunk Flags to indicate that the Verification
3370 *    Tag is reflected.
3371 *
3372 * 8) The receiver should respond to the sender of the OOTB packet with
3373 *    an ABORT.  When sending the ABORT, the receiver of the OOTB packet
3374 *    MUST fill in the Verification Tag field of the outbound packet
3375 *    with the value found in the Verification Tag field of the OOTB
3376 *    packet and set the T-bit in the Chunk Flags to indicate that the
3377 *    Verification Tag is reflected.  After sending this ABORT, the
3378 *    receiver of the OOTB packet shall discard the OOTB packet and take
3379 *    no further action.
3380 */
3381sctp_disposition_t sctp_sf_ootb(struct net *net,
3382                                const struct sctp_endpoint *ep,
3383                                const struct sctp_association *asoc,
3384                                const sctp_subtype_t type,
3385                                void *arg,
3386                                sctp_cmd_seq_t *commands)
3387{
3388        struct sctp_chunk *chunk = arg;
3389        struct sk_buff *skb = chunk->skb;
3390        sctp_chunkhdr_t *ch;
3391        sctp_errhdr_t *err;
3392        __u8 *ch_end;
3393        int ootb_shut_ack = 0;
3394        int ootb_cookie_ack = 0;
3395
3396        SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3397
3398        ch = (sctp_chunkhdr_t *) chunk->chunk_hdr;
3399        do {
3400                /* Report violation if the chunk is less then minimal */
3401                if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
3402                        return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3403                                                  commands);
3404
3405                /* Now that we know we at least have a chunk header,
3406                 * do things that are type appropriate.
3407                 */
3408                if (SCTP_CID_SHUTDOWN_ACK == ch->type)
3409                        ootb_shut_ack = 1;
3410
3411                /* RFC 2960, Section 3.3.7
3412                 *   Moreover, under any circumstances, an endpoint that
3413                 *   receives an ABORT  MUST NOT respond to that ABORT by
3414                 *   sending an ABORT of its own.
3415                 */
3416                if (SCTP_CID_ABORT == ch->type)
3417                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3418
3419                /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
3420                 * or a COOKIE ACK the SCTP Packet should be silently
3421                 * discarded.
3422                 */
3423
3424                if (SCTP_CID_COOKIE_ACK == ch->type)
3425                        ootb_cookie_ack = 1;
3426
3427                if (SCTP_CID_ERROR == ch->type) {
3428                        sctp_walk_errors(err, ch) {
3429                                if (SCTP_ERROR_STALE_COOKIE == err->cause) {
3430                                        ootb_cookie_ack = 1;
3431                                        break;
3432                                }
3433                        }
3434                }
3435
3436                /* Report violation if chunk len overflows */
3437                ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
3438                if (ch_end > skb_tail_pointer(skb))
3439                        return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3440                                                  commands);
3441
3442                ch = (sctp_chunkhdr_t *) ch_end;
3443        } while (ch_end < skb_tail_pointer(skb));
3444
3445        if (ootb_shut_ack)
3446                return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands);
3447        else if (ootb_cookie_ack)
3448                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3449        else
3450                return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
3451}
3452
3453/*
3454 * Handle an "Out of the blue" SHUTDOWN ACK.
3455 *
3456 * Section: 8.4 5, sctpimpguide 2.41.
3457 *
3458 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3459 *    respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3460 *    When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3461 *    packet must fill in the Verification Tag field of the outbound
3462 *    packet with the Verification Tag received in the SHUTDOWN ACK and
3463 *    set the T-bit in the Chunk Flags to indicate that the Verification
3464 *    Tag is reflected.
3465 *
3466 * Inputs
3467 * (endpoint, asoc, type, arg, commands)
3468 *
3469 * Outputs
3470 * (sctp_disposition_t)
3471 *
3472 * The return value is the disposition of the chunk.
3473 */
3474static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net,
3475                                             const struct sctp_endpoint *ep,
3476                                             const struct sctp_association *asoc,
3477                                             const sctp_subtype_t type,
3478                                             void *arg,
3479                                             sctp_cmd_seq_t *commands)
3480{
3481        struct sctp_packet *packet = NULL;
3482        struct sctp_chunk *chunk = arg;
3483        struct sctp_chunk *shut;
3484
3485        packet = sctp_ootb_pkt_new(net, asoc, chunk);
3486
3487        if (packet) {
3488                /* Make an SHUTDOWN_COMPLETE.
3489                 * The T bit will be set if the asoc is NULL.
3490                 */
3491                shut = sctp_make_shutdown_complete(asoc, chunk);
3492                if (!shut) {
3493                        sctp_ootb_pkt_free(packet);
3494                        return SCTP_DISPOSITION_NOMEM;
3495                }
3496
3497                /* Reflect vtag if T-Bit is set */
3498                if (sctp_test_T_bit(shut))
3499                        packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3500
3501                /* Set the skb to the belonging sock for accounting.  */
3502                shut->skb->sk = ep->base.sk;
3503
3504                sctp_packet_append_chunk(packet, shut);
3505
3506                sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3507                                SCTP_PACKET(packet));
3508
3509                SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3510
3511                /* If the chunk length is invalid, we don't want to process
3512                 * the reset of the packet.
3513                 */
3514                if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3515                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3516
3517                /* We need to discard the rest of the packet to prevent
3518                 * potential bomming attacks from additional bundled chunks.
3519                 * This is documented in SCTP Threats ID.
3520                 */
3521                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3522        }
3523
3524        return SCTP_DISPOSITION_NOMEM;
3525}
3526
3527/*
3528 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
3529 *
3530 * Verification Tag:  8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
3531 *   If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
3532 *   procedures in section 8.4 SHOULD be followed, in other words it
3533 *   should be treated as an Out Of The Blue packet.
3534 *   [This means that we do NOT check the Verification Tag on these
3535 *   chunks. --piggy ]
3536 *
3537 */
3538sctp_disposition_t sctp_sf_do_8_5_1_E_sa(struct net *net,
3539                                      const struct sctp_endpoint *ep,
3540                                      const struct sctp_association *asoc,
3541                                      const sctp_subtype_t type,
3542                                      void *arg,
3543                                      sctp_cmd_seq_t *commands)
3544{
3545        struct sctp_chunk *chunk = arg;
3546
3547        /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3548        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3549                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3550                                                  commands);
3551
3552        /* Although we do have an association in this case, it corresponds
3553         * to a restarted association. So the packet is treated as an OOTB
3554         * packet and the state function that handles OOTB SHUTDOWN_ACK is
3555         * called with a NULL association.
3556         */
3557        SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3558
3559        return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands);
3560}
3561
3562/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.  */
3563sctp_disposition_t sctp_sf_do_asconf(struct net *net,
3564                                     const struct sctp_endpoint *ep,
3565                                     const struct sctp_association *asoc,
3566                                     const sctp_subtype_t type, void *arg,
3567                                     sctp_cmd_seq_t *commands)
3568{
3569        struct sctp_chunk       *chunk = arg;
3570        struct sctp_chunk       *asconf_ack = NULL;
3571        struct sctp_paramhdr    *err_param = NULL;
3572        sctp_addiphdr_t         *hdr;
3573        union sctp_addr_param   *addr_param;
3574        __u32                   serial;
3575        int                     length;
3576
3577        if (!sctp_vtag_verify(chunk, asoc)) {
3578                sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3579                                SCTP_NULL());
3580                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3581        }
3582
3583        /* ADD-IP: Section 4.1.1
3584         * This chunk MUST be sent in an authenticated way by using
3585         * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3586         * is received unauthenticated it MUST be silently discarded as
3587         * described in [I-D.ietf-tsvwg-sctp-auth].
3588         */
3589        if (!net->sctp.addip_noauth && !chunk->auth)
3590                return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
3591
3592        /* Make sure that the ASCONF ADDIP chunk has a valid length.  */
3593        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t)))
3594                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3595                                                  commands);
3596
3597        hdr = (sctp_addiphdr_t *)chunk->skb->data;
3598        serial = ntohl(hdr->serial);
3599
3600        addr_param = (union sctp_addr_param *)hdr->params;
3601        length = ntohs(addr_param->p.length);
3602        if (length < sizeof(sctp_paramhdr_t))
3603                return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3604                           (void *)addr_param, commands);
3605
3606        /* Verify the ASCONF chunk before processing it. */
3607        if (!sctp_verify_asconf(asoc,
3608                            (sctp_paramhdr_t *)((void *)addr_param + length),
3609                            (void *)chunk->chunk_end,
3610                            &err_param))
3611                return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3612                                                  (void *)err_param, commands);
3613
3614        /* ADDIP 5.2 E1) Compare the value of the serial number to the value
3615         * the endpoint stored in a new association variable
3616         * 'Peer-Serial-Number'.
3617         */
3618        if (serial == asoc->peer.addip_serial + 1) {
3619                /* If this is the first instance of ASCONF in the packet,
3620                 * we can clean our old ASCONF-ACKs.
3621                 */
3622                if (!chunk->has_asconf)
3623                        sctp_assoc_clean_asconf_ack_cache(asoc);
3624
3625                /* ADDIP 5.2 E4) When the Sequence Number matches the next one
3626                 * expected, process the ASCONF as described below and after
3627                 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
3628                 * the response packet and cache a copy of it (in the event it
3629                 * later needs to be retransmitted).
3630                 *
3631                 * Essentially, do V1-V5.
3632                 */
3633                asconf_ack = sctp_process_asconf((struct sctp_association *)
3634                                                 asoc, chunk);
3635                if (!asconf_ack)
3636                        return SCTP_DISPOSITION_NOMEM;
3637        } else if (serial < asoc->peer.addip_serial + 1) {
3638                /* ADDIP 5.2 E2)
3639                 * If the value found in the Sequence Number is less than the
3640                 * ('Peer- Sequence-Number' + 1), simply skip to the next
3641                 * ASCONF, and include in the outbound response packet
3642                 * any previously cached ASCONF-ACK response that was
3643                 * sent and saved that matches the Sequence Number of the
3644                 * ASCONF.  Note: It is possible that no cached ASCONF-ACK
3645                 * Chunk exists.  This will occur when an older ASCONF
3646                 * arrives out of order.  In such a case, the receiver
3647                 * should skip the ASCONF Chunk and not include ASCONF-ACK
3648                 * Chunk for that chunk.
3649                 */
3650                asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
3651                if (!asconf_ack)
3652                        return SCTP_DISPOSITION_DISCARD;
3653
3654                /* Reset the transport so that we select the correct one
3655                 * this time around.  This is to make sure that we don't
3656                 * accidentally use a stale transport that's been removed.
3657                 */
3658                asconf_ack->transport = NULL;
3659        } else {
3660                /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
3661                 * it must be either a stale packet or from an attacker.
3662                 */
3663                return SCTP_DISPOSITION_DISCARD;
3664        }
3665
3666        /* ADDIP 5.2 E6)  The destination address of the SCTP packet
3667         * containing the ASCONF-ACK Chunks MUST be the source address of
3668         * the SCTP packet that held the ASCONF Chunks.
3669         *
3670         * To do this properly, we'll set the destination address of the chunk
3671         * and at the transmit time, will try look up the transport to use.
3672         * Since ASCONFs may be bundled, the correct transport may not be
3673         * created until we process the entire packet, thus this workaround.
3674         */
3675        asconf_ack->dest = chunk->source;
3676        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
3677        if (asoc->new_transport) {
3678                sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport,
3679                    commands);
3680                ((struct sctp_association *)asoc)->new_transport = NULL;
3681        }
3682
3683        return SCTP_DISPOSITION_CONSUME;
3684}
3685
3686/*
3687 * ADDIP Section 4.3 General rules for address manipulation
3688 * When building TLV parameters for the ASCONF Chunk that will add or
3689 * delete IP addresses the D0 to D13 rules should be applied:
3690 */
3691sctp_disposition_t sctp_sf_do_asconf_ack(struct net *net,
3692                                         const struct sctp_endpoint *ep,
3693                                         const struct sctp_association *asoc,
3694                                         const sctp_subtype_t type, void *arg,
3695                                         sctp_cmd_seq_t *commands)
3696{
3697        struct sctp_chunk       *asconf_ack = arg;
3698        struct sctp_chunk       *last_asconf = asoc->addip_last_asconf;
3699        struct sctp_chunk       *abort;
3700        struct sctp_paramhdr    *err_param = NULL;
3701        sctp_addiphdr_t         *addip_hdr;
3702        __u32                   sent_serial, rcvd_serial;
3703
3704        if (!sctp_vtag_verify(asconf_ack, asoc)) {
3705                sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3706                                SCTP_NULL());
3707                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3708        }
3709
3710        /* ADD-IP, Section 4.1.2:
3711         * This chunk MUST be sent in an authenticated way by using
3712         * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3713         * is received unauthenticated it MUST be silently discarded as
3714         * described in [I-D.ietf-tsvwg-sctp-auth].
3715         */
3716        if (!net->sctp.addip_noauth && !asconf_ack->auth)
3717                return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
3718
3719        /* Make sure that the ADDIP chunk has a valid length.  */
3720        if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t)))
3721                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3722                                                  commands);
3723
3724        addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data;
3725        rcvd_serial = ntohl(addip_hdr->serial);
3726
3727        /* Verify the ASCONF-ACK chunk before processing it. */
3728        if (!sctp_verify_asconf(asoc,
3729            (sctp_paramhdr_t *)addip_hdr->params,
3730            (void *)asconf_ack->chunk_end,
3731            &err_param))
3732                return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3733                           (void *)err_param, commands);
3734
3735        if (last_asconf) {
3736                addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr;
3737                sent_serial = ntohl(addip_hdr->serial);
3738        } else {
3739                sent_serial = asoc->addip_serial - 1;
3740        }
3741
3742        /* D0) If an endpoint receives an ASCONF-ACK that is greater than or
3743         * equal to the next serial number to be used but no ASCONF chunk is
3744         * outstanding the endpoint MUST ABORT the association. Note that a
3745         * sequence number is greater than if it is no more than 2^^31-1
3746         * larger than the current sequence number (using serial arithmetic).
3747         */
3748        if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
3749            !(asoc->addip_last_asconf)) {
3750                abort = sctp_make_abort(asoc, asconf_ack,
3751                                        sizeof(sctp_errhdr_t));
3752                if (abort) {
3753                        sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
3754                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3755                                        SCTP_CHUNK(abort));
3756                }
3757                /* We are going to ABORT, so we might as well stop
3758                 * processing the rest of the chunks in the packet.
3759                 */
3760                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3761                                SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3762                sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
3763                sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3764                                SCTP_ERROR(ECONNABORTED));
3765                sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3766                                SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3767                SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
3768                SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3769                return SCTP_DISPOSITION_ABORT;
3770        }
3771
3772        if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
3773                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3774                                SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3775
3776                if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
3777                                             asconf_ack)) {
3778                        /* Successfully processed ASCONF_ACK.  We can
3779                         * release the next asconf if we have one.
3780                         */
3781                        sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF,
3782                                        SCTP_NULL());
3783                        return SCTP_DISPOSITION_CONSUME;
3784                }
3785
3786                abort = sctp_make_abort(asoc, asconf_ack,
3787                                        sizeof(sctp_errhdr_t));
3788                if (abort) {
3789                        sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
3790                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3791                                        SCTP_CHUNK(abort));
3792                }
3793                /* We are going to ABORT, so we might as well stop
3794                 * processing the rest of the chunks in the packet.
3795                 */
3796                sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL());
3797                sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3798                                SCTP_ERROR(ECONNABORTED));
3799                sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3800                                SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3801                SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
3802                SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3803                return SCTP_DISPOSITION_ABORT;
3804        }
3805
3806        return SCTP_DISPOSITION_DISCARD;
3807}
3808
3809/*
3810 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
3811 *
3812 * When a FORWARD TSN chunk arrives, the data receiver MUST first update
3813 * its cumulative TSN point to the value carried in the FORWARD TSN
3814 * chunk, and then MUST further advance its cumulative TSN point locally
3815 * if possible.
3816 * After the above processing, the data receiver MUST stop reporting any
3817 * missing TSNs earlier than or equal to the new cumulative TSN point.
3818 *
3819 * Verification Tag:  8.5 Verification Tag [Normal verification]
3820 *
3821 * The return value is the disposition of the chunk.
3822 */
3823sctp_disposition_t sctp_sf_eat_fwd_tsn(struct net *net,
3824                                       const struct sctp_endpoint *ep,
3825                                       const struct sctp_association *asoc,
3826                                       const sctp_subtype_t type,
3827                                       void *arg,
3828                                       sctp_cmd_seq_t *commands)
3829{
3830        struct sctp_chunk *chunk = arg;
3831        struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3832        struct sctp_fwdtsn_skip *skip;
3833        __u16 len;
3834        __u32 tsn;
3835
3836        if (!sctp_vtag_verify(chunk, asoc)) {
3837                sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3838                                SCTP_NULL());
3839                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3840        }
3841
3842        /* Make sure that the FORWARD_TSN chunk has valid length.  */
3843        if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3844                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3845                                                  commands);
3846
3847        fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
3848        chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
3849        len = ntohs(chunk->chunk_hdr->length);
3850        len -= sizeof(struct sctp_chunkhdr);
3851        skb_pull(chunk->skb, len);
3852
3853        tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3854        SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn);
3855
3856        /* The TSN is too high--silently discard the chunk and count on it
3857         * getting retransmitted later.
3858         */
3859        if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
3860                goto discard_noforce;
3861
3862        /* Silently discard the chunk if stream-id is not valid */
3863        sctp_walk_fwdtsn(skip, chunk) {
3864                if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams)
3865                        goto discard_noforce;
3866        }
3867
3868        sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
3869        if (len > sizeof(struct sctp_fwdtsn_hdr))
3870                sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
3871                                SCTP_CHUNK(chunk));
3872
3873        /* Count this as receiving DATA. */
3874        if (asoc->autoclose) {
3875                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3876                                SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
3877        }
3878
3879        /* FIXME: For now send a SACK, but DATA processing may
3880         * send another.
3881         */
3882        sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
3883
3884        return SCTP_DISPOSITION_CONSUME;
3885
3886discard_noforce:
3887        return SCTP_DISPOSITION_DISCARD;
3888}
3889
3890sctp_disposition_t sctp_sf_eat_fwd_tsn_fast(
3891        struct net *net,
3892        const struct sctp_endpoint *ep,
3893        const struct sctp_association *asoc,
3894        const sctp_subtype_t type,
3895        void *arg,
3896        sctp_cmd_seq_t *commands)
3897{
3898        struct sctp_chunk *chunk = arg;
3899        struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3900        struct sctp_fwdtsn_skip *skip;
3901        __u16 len;
3902        __u32 tsn;
3903
3904        if (!sctp_vtag_verify(chunk, asoc)) {
3905                sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3906                                SCTP_NULL());
3907                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3908        }
3909
3910        /* Make sure that the FORWARD_TSN chunk has a valid length.  */
3911        if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3912                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3913                                                  commands);
3914
3915        fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
3916        chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
3917        len = ntohs(chunk->chunk_hdr->length);
3918        len -= sizeof(struct sctp_chunkhdr);
3919        skb_pull(chunk->skb, len);
3920
3921        tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3922        SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn);
3923
3924        /* The TSN is too high--silently discard the chunk and count on it
3925         * getting retransmitted later.
3926         */
3927        if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
3928                goto gen_shutdown;
3929
3930        /* Silently discard the chunk if stream-id is not valid */
3931        sctp_walk_fwdtsn(skip, chunk) {
3932                if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams)
3933                        goto gen_shutdown;
3934        }
3935
3936        sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
3937        if (len > sizeof(struct sctp_fwdtsn_hdr))
3938                sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
3939                                SCTP_CHUNK(chunk));
3940
3941        /* Go a head and force a SACK, since we are shutting down. */
3942gen_shutdown:
3943        /* Implementor's Guide.
3944         *
3945         * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3946         * respond to each received packet containing one or more DATA chunk(s)
3947         * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3948         */
3949        sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3950        sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3951        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3952                        SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3953
3954        return SCTP_DISPOSITION_CONSUME;
3955}
3956
3957/*
3958 * SCTP-AUTH Section 6.3 Receiving authenticated chukns
3959 *
3960 *    The receiver MUST use the HMAC algorithm indicated in the HMAC
3961 *    Identifier field.  If this algorithm was not specified by the
3962 *    receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk
3963 *    during association setup, the AUTH chunk and all chunks after it MUST
3964 *    be discarded and an ERROR chunk SHOULD be sent with the error cause
3965 *    defined in Section 4.1.
3966 *
3967 *    If an endpoint with no shared key receives a Shared Key Identifier
3968 *    other than 0, it MUST silently discard all authenticated chunks.  If
3969 *    the endpoint has at least one endpoint pair shared key for the peer,
3970 *    it MUST use the key specified by the Shared Key Identifier if a
3971 *    key has been configured for that Shared Key Identifier.  If no
3972 *    endpoint pair shared key has been configured for that Shared Key
3973 *    Identifier, all authenticated chunks MUST be silently discarded.
3974 *
3975 * Verification Tag:  8.5 Verification Tag [Normal verification]
3976 *
3977 * The return value is the disposition of the chunk.
3978 */
3979static sctp_ierror_t sctp_sf_authenticate(struct net *net,
3980                                    const struct sctp_endpoint *ep,
3981                                    const struct sctp_association *asoc,
3982                                    const sctp_subtype_t type,
3983                                    struct sctp_chunk *chunk)
3984{
3985        struct sctp_authhdr *auth_hdr;
3986        struct sctp_hmac *hmac;
3987        unsigned int sig_len;
3988        __u16 key_id;
3989        __u8 *save_digest;
3990        __u8 *digest;
3991
3992        /* Pull in the auth header, so we can do some more verification */
3993        auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
3994        chunk->subh.auth_hdr = auth_hdr;
3995        skb_pull(chunk->skb, sizeof(struct sctp_authhdr));
3996
3997        /* Make sure that we suport the HMAC algorithm from the auth
3998         * chunk.
3999         */
4000        if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
4001                return SCTP_IERROR_AUTH_BAD_HMAC;
4002
4003        /* Make sure that the provided shared key identifier has been
4004         * configured
4005         */
4006        key_id = ntohs(auth_hdr->shkey_id);
4007        if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id))
4008                return SCTP_IERROR_AUTH_BAD_KEYID;
4009
4010
4011        /* Make sure that the length of the signature matches what
4012         * we expect.
4013         */
4014        sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t);
4015        hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id));
4016        if (sig_len != hmac->hmac_len)
4017                return SCTP_IERROR_PROTO_VIOLATION;
4018
4019        /* Now that we've done validation checks, we can compute and
4020         * verify the hmac.  The steps involved are:
4021         *  1. Save the digest from the chunk.
4022         *  2. Zero out the digest in the chunk.
4023         *  3. Compute the new digest
4024         *  4. Compare saved and new digests.
4025         */
4026        digest = auth_hdr->hmac;
4027        skb_pull(chunk->skb, sig_len);
4028
4029        save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
4030        if (!save_digest)
4031                goto nomem;
4032
4033        memset(digest, 0, sig_len);
4034
4035        sctp_auth_calculate_hmac(asoc, chunk->skb,
4036                                (struct sctp_auth_chunk *)chunk->chunk_hdr,
4037                                GFP_ATOMIC);
4038
4039        /* Discard the packet if the digests do not match */
4040        if (memcmp(save_digest, digest, sig_len)) {
4041                kfree(save_digest);
4042                return SCTP_IERROR_BAD_SIG;
4043        }
4044
4045        kfree(save_digest);
4046        chunk->auth = 1;
4047
4048        return SCTP_IERROR_NO_ERROR;
4049nomem:
4050        return SCTP_IERROR_NOMEM;
4051}
4052
4053sctp_disposition_t sctp_sf_eat_auth(struct net *net,
4054                                    const struct sctp_endpoint *ep,
4055                                    const struct sctp_association *asoc,
4056                                    const sctp_subtype_t type,
4057                                    void *arg,
4058                                    sctp_cmd_seq_t *commands)
4059{
4060        struct sctp_authhdr *auth_hdr;
4061        struct sctp_chunk *chunk = arg;
4062        struct sctp_chunk *err_chunk;
4063        sctp_ierror_t error;
4064
4065        /* Make sure that the peer has AUTH capable */
4066        if (!asoc->peer.auth_capable)
4067                return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4068
4069        if (!sctp_vtag_verify(chunk, asoc)) {
4070                sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4071                                SCTP_NULL());
4072                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4073        }
4074
4075        /* Make sure that the AUTH chunk has valid length.  */
4076        if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk)))
4077                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4078                                                  commands);
4079
4080        auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4081        error = sctp_sf_authenticate(net, ep, asoc, type, chunk);
4082        switch (error) {
4083        case SCTP_IERROR_AUTH_BAD_HMAC:
4084                /* Generate the ERROR chunk and discard the rest
4085                 * of the packet
4086                 */
4087                err_chunk = sctp_make_op_error(asoc, chunk,
4088                                               SCTP_ERROR_UNSUP_HMAC,
4089                                               &auth_hdr->hmac_id,
4090                                               sizeof(__u16), 0);
4091                if (err_chunk) {
4092                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4093                                        SCTP_CHUNK(err_chunk));
4094                }
4095                /* Fall Through */
4096        case SCTP_IERROR_AUTH_BAD_KEYID:
4097        case SCTP_IERROR_BAD_SIG:
4098                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4099
4100        case SCTP_IERROR_PROTO_VIOLATION:
4101                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4102                                                  commands);
4103
4104        case SCTP_IERROR_NOMEM:
4105                return SCTP_DISPOSITION_NOMEM;
4106
4107        default:                        /* Prevent gcc warnings */
4108                break;
4109        }
4110
4111        if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
4112                struct sctp_ulpevent *ev;
4113
4114                ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
4115                                    SCTP_AUTH_NEWKEY, GFP_ATOMIC);
4116
4117                if (!ev)
4118                        return -ENOMEM;
4119
4120                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4121                                SCTP_ULPEVENT(ev));
4122        }
4123
4124        return SCTP_DISPOSITION_CONSUME;
4125}
4126
4127/*
4128 * Process an unknown chunk.
4129 *
4130 * Section: 3.2. Also, 2.1 in the implementor's guide.
4131 *
4132 * Chunk Types are encoded such that the highest-order two bits specify
4133 * the action that must be taken if the processing endpoint does not
4134 * recognize the Chunk Type.
4135 *
4136 * 00 - Stop processing this SCTP packet and discard it, do not process
4137 *      any further chunks within it.
4138 *
4139 * 01 - Stop processing this SCTP packet and discard it, do not process
4140 *      any further chunks within it, and report the unrecognized
4141 *      chunk in an 'Unrecognized Chunk Type'.
4142 *
4143 * 10 - Skip this chunk and continue processing.
4144 *
4145 * 11 - Skip this chunk and continue processing, but report in an ERROR
4146 *      Chunk using the 'Unrecognized Chunk Type' cause of error.
4147 *
4148 * The return value is the disposition of the chunk.
4149 */
4150sctp_disposition_t sctp_sf_unk_chunk(struct net *net,
4151                                     const struct sctp_endpoint *ep,
4152                                     const struct sctp_association *asoc,
4153                                     const sctp_subtype_t type,
4154                                     void *arg,
4155                                     sctp_cmd_seq_t *commands)
4156{
4157        struct sctp_chunk *unk_chunk = arg;
4158        struct sctp_chunk *err_chunk;
4159        sctp_chunkhdr_t *hdr;
4160
4161        SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk);
4162
4163        if (!sctp_vtag_verify(unk_chunk, asoc))
4164                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4165
4166        /* Make sure that the chunk has a valid length.
4167         * Since we don't know the chunk type, we use a general
4168         * chunkhdr structure to make a comparison.
4169         */
4170        if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t)))
4171                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4172                                                  commands);
4173
4174        switch (type.chunk & SCTP_CID_ACTION_MASK) {
4175        case SCTP_CID_ACTION_DISCARD:
4176                /* Discard the packet.  */
4177                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4178                break;
4179        case SCTP_CID_ACTION_DISCARD_ERR:
4180                /* Generate an ERROR chunk as response. */
4181                hdr = unk_chunk->chunk_hdr;
4182                err_chunk = sctp_make_op_error(asoc, unk_chunk,
4183                                               SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4184                                               WORD_ROUND(ntohs(hdr->length)),
4185                                               0);
4186                if (err_chunk) {
4187                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4188                                        SCTP_CHUNK(err_chunk));
4189                }
4190
4191                /* Discard the packet.  */
4192                sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4193                return SCTP_DISPOSITION_CONSUME;
4194                break;
4195        case SCTP_CID_ACTION_SKIP:
4196                /* Skip the chunk.  */
4197                return SCTP_DISPOSITION_DISCARD;
4198                break;
4199        case SCTP_CID_ACTION_SKIP_ERR:
4200                /* Generate an ERROR chunk as response. */
4201                hdr = unk_chunk->chunk_hdr;
4202                err_chunk = sctp_make_op_error(asoc, unk_chunk,
4203                                               SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4204                                               WORD_ROUND(ntohs(hdr->length)),
4205                                               0);
4206                if (err_chunk) {
4207                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4208                                        SCTP_CHUNK(err_chunk));
4209                }
4210                /* Skip the chunk.  */
4211                return SCTP_DISPOSITION_CONSUME;
4212                break;
4213        default:
4214                break;
4215        }
4216
4217        return SCTP_DISPOSITION_DISCARD;
4218}
4219
4220/*
4221 * Discard the chunk.
4222 *
4223 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
4224 * [Too numerous to mention...]
4225 * Verification Tag: No verification needed.
4226 * Inputs
4227 * (endpoint, asoc, chunk)
4228 *
4229 * Outputs
4230 * (asoc, reply_msg, msg_up, timers, counters)
4231 *
4232 * The return value is the disposition of the chunk.
4233 */
4234sctp_disposition_t sctp_sf_discard_chunk(struct net *net,
4235                                         const struct sctp_endpoint *ep,
4236                                         const struct sctp_association *asoc,
4237                                         const sctp_subtype_t type,
4238                                         void *arg,
4239                                         sctp_cmd_seq_t *commands)
4240{
4241        struct sctp_chunk *chunk = arg;
4242
4243        /* Make sure that the chunk has a valid length.
4244         * Since we don't know the chunk type, we use a general
4245         * chunkhdr structure to make a comparison.
4246         */
4247        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
4248                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4249                                                  commands);
4250
4251        SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk);
4252        return SCTP_DISPOSITION_DISCARD;
4253}
4254
4255/*
4256 * Discard the whole packet.
4257 *
4258 * Section: 8.4 2)
4259 *
4260 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
4261 *    silently discard the OOTB packet and take no further action.
4262 *
4263 * Verification Tag: No verification necessary
4264 *
4265 * Inputs
4266 * (endpoint, asoc, chunk)
4267 *
4268 * Outputs
4269 * (asoc, reply_msg, msg_up, timers, counters)
4270 *
4271 * The return value is the disposition of the chunk.
4272 */
4273sctp_disposition_t sctp_sf_pdiscard(struct net *net,
4274                                    const struct sctp_endpoint *ep,
4275                                    const struct sctp_association *asoc,
4276                                    const sctp_subtype_t type,
4277                                    void *arg,
4278                                    sctp_cmd_seq_t *commands)
4279{
4280        SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
4281        sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4282
4283        return SCTP_DISPOSITION_CONSUME;
4284}
4285
4286
4287/*
4288 * The other end is violating protocol.
4289 *
4290 * Section: Not specified
4291 * Verification Tag: Not specified
4292 * Inputs
4293 * (endpoint, asoc, chunk)
4294 *
4295 * Outputs
4296 * (asoc, reply_msg, msg_up, timers, counters)
4297 *
4298 * We simply tag the chunk as a violation.  The state machine will log
4299 * the violation and continue.
4300 */
4301sctp_disposition_t sctp_sf_violation(struct net *net,
4302                                     const struct sctp_endpoint *ep,
4303                                     const struct sctp_association *asoc,
4304                                     const sctp_subtype_t type,
4305                                     void *arg,
4306                                     sctp_cmd_seq_t *commands)
4307{
4308        struct sctp_chunk *chunk = arg;
4309
4310        /* Make sure that the chunk has a valid length. */
4311        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
4312                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4313                                                  commands);
4314
4315        return SCTP_DISPOSITION_VIOLATION;
4316}
4317
4318/*
4319 * Common function to handle a protocol violation.
4320 */
4321static sctp_disposition_t sctp_sf_abort_violation(
4322                                     struct net *net,
4323                                     const struct sctp_endpoint *ep,
4324                                     const struct sctp_association *asoc,
4325                                     void *arg,
4326                                     sctp_cmd_seq_t *commands,
4327                                     const __u8 *payload,
4328                                     const size_t paylen)
4329{
4330        struct sctp_packet *packet = NULL;
4331        struct sctp_chunk *chunk =  arg;
4332        struct sctp_chunk *abort = NULL;
4333
4334        /* SCTP-AUTH, Section 6.3:
4335         *    It should be noted that if the receiver wants to tear
4336         *    down an association in an authenticated way only, the
4337         *    handling of malformed packets should not result in
4338         *    tearing down the association.
4339         *
4340         * This means that if we only want to abort associations
4341         * in an authenticated way (i.e AUTH+ABORT), then we
4342         * can't destroy this association just because the packet
4343         * was malformed.
4344         */
4345        if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4346                goto discard;
4347
4348        /* Make the abort chunk. */
4349        abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
4350        if (!abort)
4351                goto nomem;
4352
4353        if (asoc) {
4354                /* Treat INIT-ACK as a special case during COOKIE-WAIT. */
4355                if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK &&
4356                    !asoc->peer.i.init_tag) {
4357                        sctp_initack_chunk_t *initack;
4358
4359                        initack = (sctp_initack_chunk_t *)chunk->chunk_hdr;
4360                        if (!sctp_chunk_length_valid(chunk,
4361                                                     sizeof(sctp_initack_chunk_t)))
4362                                abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T;
4363                        else {
4364                                unsigned int inittag;
4365
4366                                inittag = ntohl(initack->init_hdr.init_tag);
4367                                sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
4368                                                SCTP_U32(inittag));
4369                        }
4370                }
4371
4372                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4373                SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4374
4375                if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
4376                        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4377                                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4378                        sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4379                                        SCTP_ERROR(ECONNREFUSED));
4380                        sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4381                                        SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4382                } else {
4383                        sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4384                                        SCTP_ERROR(ECONNABORTED));
4385                        sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4386                                        SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4387                        SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4388                }
4389        } else {
4390                packet = sctp_ootb_pkt_new(net, asoc, chunk);
4391
4392                if (!packet)
4393                        goto nomem_pkt;
4394
4395                if (sctp_test_T_bit(abort))
4396                        packet->vtag = ntohl(chunk->sctp_hdr->vtag);
4397
4398                abort->skb->sk = ep->base.sk;
4399
4400                sctp_packet_append_chunk(packet, abort);
4401
4402                sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
4403                        SCTP_PACKET(packet));
4404
4405                SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4406        }
4407
4408        SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4409
4410discard:
4411        sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4412        return SCTP_DISPOSITION_ABORT;
4413
4414nomem_pkt:
4415        sctp_chunk_free(abort);
4416nomem:
4417        return SCTP_DISPOSITION_NOMEM;
4418}
4419
4420/*
4421 * Handle a protocol violation when the chunk length is invalid.
4422 * "Invalid" length is identified as smaller than the minimal length a
4423 * given chunk can be.  For example, a SACK chunk has invalid length
4424 * if its length is set to be smaller than the size of sctp_sack_chunk_t.
4425 *
4426 * We inform the other end by sending an ABORT with a Protocol Violation
4427 * error code.
4428 *
4429 * Section: Not specified
4430 * Verification Tag:  Nothing to do
4431 * Inputs
4432 * (endpoint, asoc, chunk)
4433 *
4434 * Outputs
4435 * (reply_msg, msg_up, counters)
4436 *
4437 * Generate an  ABORT chunk and terminate the association.
4438 */
4439static sctp_disposition_t sctp_sf_violation_chunklen(
4440                                     struct net *net,
4441                                     const struct sctp_endpoint *ep,
4442                                     const struct sctp_association *asoc,
4443                                     const sctp_subtype_t type,
4444                                     void *arg,
4445                                     sctp_cmd_seq_t *commands)
4446{
4447        static const char err_str[]="The following chunk had invalid length:";
4448
4449        return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4450                                        sizeof(err_str));
4451}
4452
4453/*
4454 * Handle a protocol violation when the parameter length is invalid.
4455 * If the length is smaller than the minimum length of a given parameter,
4456 * or accumulated length in multi parameters exceeds the end of the chunk,
4457 * the length is considered as invalid.
4458 */
4459static sctp_disposition_t sctp_sf_violation_paramlen(
4460                                     struct net *net,
4461                                     const struct sctp_endpoint *ep,
4462                                     const struct sctp_association *asoc,
4463                                     const sctp_subtype_t type,
4464                                     void *arg, void *ext,
4465                                     sctp_cmd_seq_t *commands)
4466{
4467        struct sctp_chunk *chunk =  arg;
4468        struct sctp_paramhdr *param = ext;
4469        struct sctp_chunk *abort = NULL;
4470
4471        if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4472                goto discard;
4473
4474        /* Make the abort chunk. */
4475        abort = sctp_make_violation_paramlen(asoc, chunk, param);
4476        if (!abort)
4477                goto nomem;
4478
4479        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4480        SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4481
4482        sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4483                        SCTP_ERROR(ECONNABORTED));
4484        sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4485                        SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4486        SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4487        SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4488
4489discard:
4490        sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4491        return SCTP_DISPOSITION_ABORT;
4492nomem:
4493        return SCTP_DISPOSITION_NOMEM;
4494}
4495
4496/* Handle a protocol violation when the peer trying to advance the
4497 * cumulative tsn ack to a point beyond the max tsn currently sent.
4498 *
4499 * We inform the other end by sending an ABORT with a Protocol Violation
4500 * error code.
4501 */
4502static sctp_disposition_t sctp_sf_violation_ctsn(
4503                                     struct net *net,
4504                                     const struct sctp_endpoint *ep,
4505                                     const struct sctp_association *asoc,
4506                                     const sctp_subtype_t type,
4507                                     void *arg,
4508                                     sctp_cmd_seq_t *commands)
4509{
4510        static const char err_str[]="The cumulative tsn ack beyond the max tsn currently sent:";
4511
4512        return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4513                                        sizeof(err_str));
4514}
4515
4516/* Handle protocol violation of an invalid chunk bundling.  For example,
4517 * when we have an association and we receive bundled INIT-ACK, or
4518 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle"
4519 * statement from the specs.  Additionally, there might be an attacker
4520 * on the path and we may not want to continue this communication.
4521 */
4522static sctp_disposition_t sctp_sf_violation_chunk(
4523                                     struct net *net,
4524                                     const struct sctp_endpoint *ep,
4525                                     const struct sctp_association *asoc,
4526                                     const sctp_subtype_t type,
4527                                     void *arg,
4528                                     sctp_cmd_seq_t *commands)
4529{
4530        static const char err_str[]="The following chunk violates protocol:";
4531
4532        if (!asoc)
4533                return sctp_sf_violation(net, ep, asoc, type, arg, commands);
4534
4535        return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4536                                        sizeof(err_str));
4537}
4538/***************************************************************************
4539 * These are the state functions for handling primitive (Section 10) events.
4540 ***************************************************************************/
4541/*
4542 * sctp_sf_do_prm_asoc
4543 *
4544 * Section: 10.1 ULP-to-SCTP
4545 * B) Associate
4546 *
4547 * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
4548 * outbound stream count)
4549 * -> association id [,destination transport addr list] [,outbound stream
4550 * count]
4551 *
4552 * This primitive allows the upper layer to initiate an association to a
4553 * specific peer endpoint.
4554 *
4555 * The peer endpoint shall be specified by one of the transport addresses
4556 * which defines the endpoint (see Section 1.4).  If the local SCTP
4557 * instance has not been initialized, the ASSOCIATE is considered an
4558 * error.
4559 * [This is not relevant for the kernel implementation since we do all
4560 * initialization at boot time.  It we hadn't initialized we wouldn't
4561 * get anywhere near this code.]
4562 *
4563 * An association id, which is a local handle to the SCTP association,
4564 * will be returned on successful establishment of the association. If
4565 * SCTP is not able to open an SCTP association with the peer endpoint,
4566 * an error is returned.
4567 * [In the kernel implementation, the struct sctp_association needs to
4568 * be created BEFORE causing this primitive to run.]
4569 *
4570 * Other association parameters may be returned, including the
4571 * complete destination transport addresses of the peer as well as the
4572 * outbound stream count of the local endpoint. One of the transport
4573 * address from the returned destination addresses will be selected by
4574 * the local endpoint as default primary path for sending SCTP packets
4575 * to this peer.  The returned "destination transport addr list" can
4576 * be used by the ULP to change the default primary path or to force
4577 * sending a packet to a specific transport address.  [All of this
4578 * stuff happens when the INIT ACK arrives.  This is a NON-BLOCKING
4579 * function.]
4580 *
4581 * Mandatory attributes:
4582 *
4583 * o local SCTP instance name - obtained from the INITIALIZE operation.
4584 *   [This is the argument asoc.]
4585 * o destination transport addr - specified as one of the transport
4586 * addresses of the peer endpoint with which the association is to be
4587 * established.
4588 *  [This is asoc->peer.active_path.]
4589 * o outbound stream count - the number of outbound streams the ULP
4590 * would like to open towards this peer endpoint.
4591 * [BUG: This is not currently implemented.]
4592 * Optional attributes:
4593 *
4594 * None.
4595 *
4596 * The return value is a disposition.
4597 */
4598sctp_disposition_t sctp_sf_do_prm_asoc(struct net *net,
4599                                       const struct sctp_endpoint *ep,
4600                                       const struct sctp_association *asoc,
4601                                       const sctp_subtype_t type,
4602                                       void *arg,
4603                                       sctp_cmd_seq_t *commands)
4604{
4605        struct sctp_chunk *repl;
4606        struct sctp_association* my_asoc;
4607
4608        /* The comment below says that we enter COOKIE-WAIT AFTER
4609         * sending the INIT, but that doesn't actually work in our
4610         * implementation...
4611         */
4612        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4613                        SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
4614
4615        /* RFC 2960 5.1 Normal Establishment of an Association
4616         *
4617         * A) "A" first sends an INIT chunk to "Z".  In the INIT, "A"
4618         * must provide its Verification Tag (Tag_A) in the Initiate
4619         * Tag field.  Tag_A SHOULD be a random number in the range of
4620         * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
4621         */
4622
4623        repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
4624        if (!repl)
4625                goto nomem;
4626
4627        /* Cast away the const modifier, as we want to just
4628         * rerun it through as a sideffect.
4629         */
4630        my_asoc = (struct sctp_association *)asoc;
4631        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
4632
4633        /* Choose transport for INIT. */
4634        sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
4635                        SCTP_CHUNK(repl));
4636
4637        /* After sending the INIT, "A" starts the T1-init timer and
4638         * enters the COOKIE-WAIT state.
4639         */
4640        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
4641                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4642        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
4643        return SCTP_DISPOSITION_CONSUME;
4644
4645nomem:
4646        return SCTP_DISPOSITION_NOMEM;
4647}
4648
4649/*
4650 * Process the SEND primitive.
4651 *
4652 * Section: 10.1 ULP-to-SCTP
4653 * E) Send
4654 *
4655 * Format: SEND(association id, buffer address, byte count [,context]
4656 *         [,stream id] [,life time] [,destination transport address]
4657 *         [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
4658 * -> result
4659 *
4660 * This is the main method to send user data via SCTP.
4661 *
4662 * Mandatory attributes:
4663 *
4664 *  o association id - local handle to the SCTP association
4665 *
4666 *  o buffer address - the location where the user message to be
4667 *    transmitted is stored;
4668 *
4669 *  o byte count - The size of the user data in number of bytes;
4670 *
4671 * Optional attributes:
4672 *
4673 *  o context - an optional 32 bit integer that will be carried in the
4674 *    sending failure notification to the ULP if the transportation of
4675 *    this User Message fails.
4676 *
4677 *  o stream id - to indicate which stream to send the data on. If not
4678 *    specified, stream 0 will be used.
4679 *
4680 *  o life time - specifies the life time of the user data. The user data
4681 *    will not be sent by SCTP after the life time expires. This
4682 *    parameter can be used to avoid efforts to transmit stale
4683 *    user messages. SCTP notifies the ULP if the data cannot be
4684 *    initiated to transport (i.e. sent to the destination via SCTP's
4685 *    send primitive) within the life time variable. However, the
4686 *    user data will be transmitted if SCTP has attempted to transmit a
4687 *    chunk before the life time expired.
4688 *
4689 *  o destination transport address - specified as one of the destination
4690 *    transport addresses of the peer endpoint to which this packet
4691 *    should be sent. Whenever possible, SCTP should use this destination
4692 *    transport address for sending the packets, instead of the current
4693 *    primary path.
4694 *
4695 *  o unorder flag - this flag, if present, indicates that the user
4696 *    would like the data delivered in an unordered fashion to the peer
4697 *    (i.e., the U flag is set to 1 on all DATA chunks carrying this
4698 *    message).
4699 *
4700 *  o no-bundle flag - instructs SCTP not to bundle this user data with
4701 *    other outbound DATA chunks. SCTP MAY still bundle even when
4702 *    this flag is present, when faced with network congestion.
4703 *
4704 *  o payload protocol-id - A 32 bit unsigned integer that is to be
4705 *    passed to the peer indicating the type of payload protocol data
4706 *    being transmitted. This value is passed as opaque data by SCTP.
4707 *
4708 * The return value is the disposition.
4709 */
4710sctp_disposition_t sctp_sf_do_prm_send(struct net *net,
4711                                       const struct sctp_endpoint *ep,
4712                                       const struct sctp_association *asoc,
4713                                       const sctp_subtype_t type,
4714                                       void *arg,
4715                                       sctp_cmd_seq_t *commands)
4716{
4717        struct sctp_datamsg *msg = arg;
4718
4719        sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg));
4720        return SCTP_DISPOSITION_CONSUME;
4721}
4722
4723/*
4724 * Process the SHUTDOWN primitive.
4725 *
4726 * Section: 10.1:
4727 * C) Shutdown
4728 *
4729 * Format: SHUTDOWN(association id)
4730 * -> result
4731 *
4732 * Gracefully closes an association. Any locally queued user data
4733 * will be delivered to the peer. The association will be terminated only
4734 * after the peer acknowledges all the SCTP packets sent.  A success code
4735 * will be returned on successful termination of the association. If
4736 * attempting to terminate the association results in a failure, an error
4737 * code shall be returned.
4738 *
4739 * Mandatory attributes:
4740 *
4741 *  o association id - local handle to the SCTP association
4742 *
4743 * Optional attributes:
4744 *
4745 * None.
4746 *
4747 * The return value is the disposition.
4748 */
4749sctp_disposition_t sctp_sf_do_9_2_prm_shutdown(
4750        struct net *net,
4751        const struct sctp_endpoint *ep,
4752        const struct sctp_association *asoc,
4753        const sctp_subtype_t type,
4754        void *arg,
4755        sctp_cmd_seq_t *commands)
4756{
4757        int disposition;
4758
4759        /* From 9.2 Shutdown of an Association
4760         * Upon receipt of the SHUTDOWN primitive from its upper
4761         * layer, the endpoint enters SHUTDOWN-PENDING state and
4762         * remains there until all outstanding data has been
4763         * acknowledged by its peer. The endpoint accepts no new data
4764         * from its upper layer, but retransmits data to the far end
4765         * if necessary to fill gaps.
4766         */
4767        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4768                        SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
4769
4770        disposition = SCTP_DISPOSITION_CONSUME;
4771        if (sctp_outq_is_empty(&asoc->outqueue)) {
4772                disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
4773                                                            arg, commands);
4774        }
4775        return disposition;
4776}
4777
4778/*
4779 * Process the ABORT primitive.
4780 *
4781 * Section: 10.1:
4782 * C) Abort
4783 *
4784 * Format: Abort(association id [, cause code])
4785 * -> result
4786 *
4787 * Ungracefully closes an association. Any locally queued user data
4788 * will be discarded and an ABORT chunk is sent to the peer.  A success code
4789 * will be returned on successful abortion of the association. If
4790 * attempting to abort the association results in a failure, an error
4791 * code shall be returned.
4792 *
4793 * Mandatory attributes:
4794 *
4795 *  o association id - local handle to the SCTP association
4796 *
4797 * Optional attributes:
4798 *
4799 *  o cause code - reason of the abort to be passed to the peer
4800 *
4801 * None.
4802 *
4803 * The return value is the disposition.
4804 */
4805sctp_disposition_t sctp_sf_do_9_1_prm_abort(
4806        struct net *net,
4807        const struct sctp_endpoint *ep,
4808        const struct sctp_association *asoc,
4809        const sctp_subtype_t type,
4810        void *arg,
4811        sctp_cmd_seq_t *commands)
4812{
4813        /* From 9.1 Abort of an Association
4814         * Upon receipt of the ABORT primitive from its upper
4815         * layer, the endpoint enters CLOSED state and
4816         * discard all outstanding data has been
4817         * acknowledged by its peer. The endpoint accepts no new data
4818         * from its upper layer, but retransmits data to the far end
4819         * if necessary to fill gaps.
4820         */
4821        struct sctp_chunk *abort = arg;
4822        sctp_disposition_t retval;
4823
4824        retval = SCTP_DISPOSITION_CONSUME;
4825
4826        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4827
4828        /* Even if we can't send the ABORT due to low memory delete the
4829         * TCB.  This is a departure from our typical NOMEM handling.
4830         */
4831
4832        sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4833                        SCTP_ERROR(ECONNABORTED));
4834        /* Delete the established association. */
4835        sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4836                        SCTP_PERR(SCTP_ERROR_USER_ABORT));
4837
4838        SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4839        SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4840
4841        return retval;
4842}
4843
4844/* We tried an illegal operation on an association which is closed.  */
4845sctp_disposition_t sctp_sf_error_closed(struct net *net,
4846                                        const struct sctp_endpoint *ep,
4847                                        const struct sctp_association *asoc,
4848                                        const sctp_subtype_t type,
4849                                        void *arg,
4850                                        sctp_cmd_seq_t *commands)
4851{
4852        sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
4853        return SCTP_DISPOSITION_CONSUME;
4854}
4855
4856/* We tried an illegal operation on an association which is shutting
4857 * down.
4858 */
4859sctp_disposition_t sctp_sf_error_shutdown(struct net *net,
4860                                          const struct sctp_endpoint *ep,
4861                                          const struct sctp_association *asoc,
4862                                          const sctp_subtype_t type,
4863                                          void *arg,
4864                                          sctp_cmd_seq_t *commands)
4865{
4866        sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
4867                        SCTP_ERROR(-ESHUTDOWN));
4868        return SCTP_DISPOSITION_CONSUME;
4869}
4870
4871/*
4872 * sctp_cookie_wait_prm_shutdown
4873 *
4874 * Section: 4 Note: 2
4875 * Verification Tag:
4876 * Inputs
4877 * (endpoint, asoc)
4878 *
4879 * The RFC does not explicitly address this issue, but is the route through the
4880 * state table when someone issues a shutdown while in COOKIE_WAIT state.
4881 *
4882 * Outputs
4883 * (timers)
4884 */
4885sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown(
4886        struct net *net,
4887        const struct sctp_endpoint *ep,
4888        const struct sctp_association *asoc,
4889        const sctp_subtype_t type,
4890        void *arg,
4891        sctp_cmd_seq_t *commands)
4892{
4893        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4894                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4895
4896        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4897                        SCTP_STATE(SCTP_STATE_CLOSED));
4898
4899        SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
4900
4901        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
4902
4903        return SCTP_DISPOSITION_DELETE_TCB;
4904}
4905
4906/*
4907 * sctp_cookie_echoed_prm_shutdown
4908 *
4909 * Section: 4 Note: 2
4910 * Verification Tag:
4911 * Inputs
4912 * (endpoint, asoc)
4913 *
4914 * The RFC does not explcitly address this issue, but is the route through the
4915 * state table when someone issues a shutdown while in COOKIE_ECHOED state.
4916 *
4917 * Outputs
4918 * (timers)
4919 */
4920sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown(
4921        struct net *net,
4922        const struct sctp_endpoint *ep,
4923        const struct sctp_association *asoc,
4924        const sctp_subtype_t type,
4925        void *arg, sctp_cmd_seq_t *commands)
4926{
4927        /* There is a single T1 timer, so we should be able to use
4928         * common function with the COOKIE-WAIT state.
4929         */
4930        return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands);
4931}
4932
4933/*
4934 * sctp_sf_cookie_wait_prm_abort
4935 *
4936 * Section: 4 Note: 2
4937 * Verification Tag:
4938 * Inputs
4939 * (endpoint, asoc)
4940 *
4941 * The RFC does not explicitly address this issue, but is the route through the
4942 * state table when someone issues an abort while in COOKIE_WAIT state.
4943 *
4944 * Outputs
4945 * (timers)
4946 */
4947sctp_disposition_t sctp_sf_cookie_wait_prm_abort(
4948        struct net *net,
4949        const struct sctp_endpoint *ep,
4950        const struct sctp_association *asoc,
4951        const sctp_subtype_t type,
4952        void *arg,
4953        sctp_cmd_seq_t *commands)
4954{
4955        struct sctp_chunk *abort = arg;
4956        sctp_disposition_t retval;
4957
4958        /* Stop T1-init timer */
4959        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4960                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4961        retval = SCTP_DISPOSITION_CONSUME;
4962
4963        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4964
4965        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4966                        SCTP_STATE(SCTP_STATE_CLOSED));
4967
4968        SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4969
4970        /* Even if we can't send the ABORT due to low memory delete the
4971         * TCB.  This is a departure from our typical NOMEM handling.
4972         */
4973
4974        sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4975                        SCTP_ERROR(ECONNREFUSED));
4976        /* Delete the established association. */
4977        sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4978                        SCTP_PERR(SCTP_ERROR_USER_ABORT));
4979
4980        return retval;
4981}
4982
4983/*
4984 * sctp_sf_cookie_echoed_prm_abort
4985 *
4986 * Section: 4 Note: 3
4987 * Verification Tag:
4988 * Inputs
4989 * (endpoint, asoc)
4990 *
4991 * The RFC does not explcitly address this issue, but is the route through the
4992 * state table when someone issues an abort while in COOKIE_ECHOED state.
4993 *
4994 * Outputs
4995 * (timers)
4996 */
4997sctp_disposition_t sctp_sf_cookie_echoed_prm_abort(
4998        struct net *net,
4999        const struct sctp_endpoint *ep,
5000        const struct sctp_association *asoc,
5001        const sctp_subtype_t type,
5002        void *arg,
5003        sctp_cmd_seq_t *commands)
5004{
5005        /* There is a single T1 timer, so we should be able to use
5006         * common function with the COOKIE-WAIT state.
5007         */
5008        return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands);
5009}
5010
5011/*
5012 * sctp_sf_shutdown_pending_prm_abort
5013 *
5014 * Inputs
5015 * (endpoint, asoc)
5016 *
5017 * The RFC does not explicitly address this issue, but is the route through the
5018 * state table when someone issues an abort while in SHUTDOWN-PENDING state.
5019 *
5020 * Outputs
5021 * (timers)
5022 */
5023sctp_disposition_t sctp_sf_shutdown_pending_prm_abort(
5024        struct net *net,
5025        const struct sctp_endpoint *ep,
5026        const struct sctp_association *asoc,
5027        const sctp_subtype_t type,
5028        void *arg,
5029        sctp_cmd_seq_t *commands)
5030{
5031        /* Stop the T5-shutdown guard timer.  */
5032        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5033                        SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5034
5035        return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5036}
5037
5038/*
5039 * sctp_sf_shutdown_sent_prm_abort
5040 *
5041 * Inputs
5042 * (endpoint, asoc)
5043 *
5044 * The RFC does not explicitly address this issue, but is the route through the
5045 * state table when someone issues an abort while in SHUTDOWN-SENT state.
5046 *
5047 * Outputs
5048 * (timers)
5049 */
5050sctp_disposition_t sctp_sf_shutdown_sent_prm_abort(
5051        struct net *net,
5052        const struct sctp_endpoint *ep,
5053        const struct sctp_association *asoc,
5054        const sctp_subtype_t type,
5055        void *arg,
5056        sctp_cmd_seq_t *commands)
5057{
5058        /* Stop the T2-shutdown timer.  */
5059        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5060                        SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5061
5062        /* Stop the T5-shutdown guard timer.  */
5063        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5064                        SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5065
5066        return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5067}
5068
5069/*
5070 * sctp_sf_cookie_echoed_prm_abort
5071 *
5072 * Inputs
5073 * (endpoint, asoc)
5074 *
5075 * The RFC does not explcitly address this issue, but is the route through the
5076 * state table when someone issues an abort while in COOKIE_ECHOED state.
5077 *
5078 * Outputs
5079 * (timers)
5080 */
5081sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort(
5082        struct net *net,
5083        const struct sctp_endpoint *ep,
5084        const struct sctp_association *asoc,
5085        const sctp_subtype_t type,
5086        void *arg,
5087        sctp_cmd_seq_t *commands)
5088{
5089        /* The same T2 timer, so we should be able to use
5090         * common function with the SHUTDOWN-SENT state.
5091         */
5092        return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands);
5093}
5094
5095/*
5096 * Process the REQUESTHEARTBEAT primitive
5097 *
5098 * 10.1 ULP-to-SCTP
5099 * J) Request Heartbeat
5100 *
5101 * Format: REQUESTHEARTBEAT(association id, destination transport address)
5102 *
5103 * -> result
5104 *
5105 * Instructs the local endpoint to perform a HeartBeat on the specified
5106 * destination transport address of the given association. The returned
5107 * result should indicate whether the transmission of the HEARTBEAT
5108 * chunk to the destination address is successful.
5109 *
5110 * Mandatory attributes:
5111 *
5112 * o association id - local handle to the SCTP association
5113 *
5114 * o destination transport address - the transport address of the
5115 *   association on which a heartbeat should be issued.
5116 */
5117sctp_disposition_t sctp_sf_do_prm_requestheartbeat(
5118                                        struct net *net,
5119                                        const struct sctp_endpoint *ep,
5120                                        const struct sctp_association *asoc,
5121                                        const sctp_subtype_t type,
5122                                        void *arg,
5123                                        sctp_cmd_seq_t *commands)
5124{
5125        if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
5126                                      (struct sctp_transport *)arg, commands))
5127                return SCTP_DISPOSITION_NOMEM;
5128
5129        /*
5130         * RFC 2960 (bis), section 8.3
5131         *
5132         *    D) Request an on-demand HEARTBEAT on a specific destination
5133         *    transport address of a given association.
5134         *
5135         *    The endpoint should increment the respective error  counter of
5136         *    the destination transport address each time a HEARTBEAT is sent
5137         *    to that address and not acknowledged within one RTO.
5138         *
5139         */
5140        sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
5141                        SCTP_TRANSPORT(arg));
5142        return SCTP_DISPOSITION_CONSUME;
5143}
5144
5145/*
5146 * ADDIP Section 4.1 ASCONF Chunk Procedures
5147 * When an endpoint has an ASCONF signaled change to be sent to the
5148 * remote endpoint it should do A1 to A9
5149 */
5150sctp_disposition_t sctp_sf_do_prm_asconf(struct net *net,
5151                                        const struct sctp_endpoint *ep,
5152                                        const struct sctp_association *asoc,
5153                                        const sctp_subtype_t type,
5154                                        void *arg,
5155                                        sctp_cmd_seq_t *commands)
5156{
5157        struct sctp_chunk *chunk = arg;
5158
5159        sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5160        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5161                        SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5162        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5163        return SCTP_DISPOSITION_CONSUME;
5164}
5165
5166/*
5167 * Ignore the primitive event
5168 *
5169 * The return value is the disposition of the primitive.
5170 */
5171sctp_disposition_t sctp_sf_ignore_primitive(
5172        struct net *net,
5173        const struct sctp_endpoint *ep,
5174        const struct sctp_association *asoc,
5175        const sctp_subtype_t type,
5176        void *arg,
5177        sctp_cmd_seq_t *commands)
5178{
5179        SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive);
5180        return SCTP_DISPOSITION_DISCARD;
5181}
5182
5183/***************************************************************************
5184 * These are the state functions for the OTHER events.
5185 ***************************************************************************/
5186
5187/*
5188 * When the SCTP stack has no more user data to send or retransmit, this
5189 * notification is given to the user. Also, at the time when a user app
5190 * subscribes to this event, if there is no data to be sent or
5191 * retransmit, the stack will immediately send up this notification.
5192 */
5193sctp_disposition_t sctp_sf_do_no_pending_tsn(
5194        struct net *net,
5195        const struct sctp_endpoint *ep,
5196        const struct sctp_association *asoc,
5197        const sctp_subtype_t type,
5198        void *arg,
5199        sctp_cmd_seq_t *commands)
5200{
5201        struct sctp_ulpevent *event;
5202
5203        event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC);
5204        if (!event)
5205                return SCTP_DISPOSITION_NOMEM;
5206
5207        sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event));
5208
5209        return SCTP_DISPOSITION_CONSUME;
5210}
5211
5212/*
5213 * Start the shutdown negotiation.
5214 *
5215 * From Section 9.2:
5216 * Once all its outstanding data has been acknowledged, the endpoint
5217 * shall send a SHUTDOWN chunk to its peer including in the Cumulative
5218 * TSN Ack field the last sequential TSN it has received from the peer.
5219 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
5220 * state. If the timer expires, the endpoint must re-send the SHUTDOWN
5221 * with the updated last sequential TSN received from its peer.
5222 *
5223 * The return value is the disposition.
5224 */
5225sctp_disposition_t sctp_sf_do_9_2_start_shutdown(
5226        struct net *net,
5227        const struct sctp_endpoint *ep,
5228        const struct sctp_association *asoc,
5229        const sctp_subtype_t type,
5230        void *arg,
5231        sctp_cmd_seq_t *commands)
5232{
5233        struct sctp_chunk *reply;
5234
5235        /* Once all its outstanding data has been acknowledged, the
5236         * endpoint shall send a SHUTDOWN chunk to its peer including
5237         * in the Cumulative TSN Ack field the last sequential TSN it
5238         * has received from the peer.
5239         */
5240        reply = sctp_make_shutdown(asoc, NULL);
5241        if (!reply)
5242                goto nomem;
5243
5244        /* Set the transport for the SHUTDOWN chunk and the timeout for the
5245         * T2-shutdown timer.
5246         */
5247        sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5248
5249        /* It shall then start the T2-shutdown timer */
5250        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5251                        SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5252
5253        /* RFC 4960 Section 9.2
5254         * The sender of the SHUTDOWN MAY also start an overall guard timer
5255         * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5256         */
5257        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5258                        SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5259
5260        if (asoc->autoclose)
5261                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5262                                SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5263
5264        /* and enter the SHUTDOWN-SENT state.  */
5265        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5266                        SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
5267
5268        /* sctp-implguide 2.10 Issues with Heartbeating and failover