linux/net/sctp/outqueue.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) 2001-2003 Intel Corp.
   6 *
   7 * This file is part of the SCTP kernel implementation
   8 *
   9 * These functions implement the sctp_outq class.   The outqueue handles
  10 * bundling and queueing of outgoing SCTP chunks.
  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 *    Perry Melange         <pmelange@null.cc.uic.edu>
  40 *    Xingang Guo           <xingang.guo@intel.com>
  41 *    Hui Huang             <hui.huang@nokia.com>
  42 *    Sridhar Samudrala     <sri@us.ibm.com>
  43 *    Jon Grimm             <jgrimm@us.ibm.com>
  44 *
  45 * Any bugs reported given to us we will try to fix... any fixes shared will
  46 * be incorporated into the next SCTP release.
  47 */
  48
  49#include <linux/types.h>
  50#include <linux/list.h>   /* For struct list_head */
  51#include <linux/socket.h>
  52#include <linux/ip.h>
  53#include <net/sock.h>     /* For skb_set_owner_w */
  54
  55#include <net/sctp/sctp.h>
  56#include <net/sctp/sm.h>
  57
  58/* Declare internal functions here.  */
  59static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn);
  60static void sctp_check_transmitted(struct sctp_outq *q,
  61                                   struct list_head *transmitted_queue,
  62                                   struct sctp_transport *transport,
  63                                   struct sctp_sackhdr *sack,
  64                                   __u32 highest_new_tsn);
  65
  66static void sctp_mark_missing(struct sctp_outq *q,
  67                              struct list_head *transmitted_queue,
  68                              struct sctp_transport *transport,
  69                              __u32 highest_new_tsn,
  70                              int count_of_newacks);
  71
  72static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn);
  73
  74static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout);
  75
  76/* Add data to the front of the queue. */
  77static inline void sctp_outq_head_data(struct sctp_outq *q,
  78                                        struct sctp_chunk *ch)
  79{
  80        list_add(&ch->list, &q->out_chunk_list);
  81        q->out_qlen += ch->skb->len;
  82        return;
  83}
  84
  85/* Take data from the front of the queue. */
  86static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q)
  87{
  88        struct sctp_chunk *ch = NULL;
  89
  90        if (!list_empty(&q->out_chunk_list)) {
  91                struct list_head *entry = q->out_chunk_list.next;
  92
  93                ch = list_entry(entry, struct sctp_chunk, list);
  94                list_del_init(entry);
  95                q->out_qlen -= ch->skb->len;
  96        }
  97        return ch;
  98}
  99/* Add data chunk to the end of the queue. */
 100static inline void sctp_outq_tail_data(struct sctp_outq *q,
 101                                       struct sctp_chunk *ch)
 102{
 103        list_add_tail(&ch->list, &q->out_chunk_list);
 104        q->out_qlen += ch->skb->len;
 105        return;
 106}
 107
 108/*
 109 * SFR-CACC algorithm:
 110 * D) If count_of_newacks is greater than or equal to 2
 111 * and t was not sent to the current primary then the
 112 * sender MUST NOT increment missing report count for t.
 113 */
 114static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary,
 115                                       struct sctp_transport *transport,
 116                                       int count_of_newacks)
 117{
 118        if (count_of_newacks >=2 && transport != primary)
 119                return 1;
 120        return 0;
 121}
 122
 123/*
 124 * SFR-CACC algorithm:
 125 * F) If count_of_newacks is less than 2, let d be the
 126 * destination to which t was sent. If cacc_saw_newack
 127 * is 0 for destination d, then the sender MUST NOT
 128 * increment missing report count for t.
 129 */
 130static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport,
 131                                       int count_of_newacks)
 132{
 133        if (count_of_newacks < 2 && !transport->cacc.cacc_saw_newack)
 134                return 1;
 135        return 0;
 136}
 137
 138/*
 139 * SFR-CACC algorithm:
 140 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD
 141 * execute steps C, D, F.
 142 *
 143 * C has been implemented in sctp_outq_sack
 144 */
 145static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary,
 146                                     struct sctp_transport *transport,
 147                                     int count_of_newacks)
 148{
 149        if (!primary->cacc.cycling_changeover) {
 150                if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks))
 151                        return 1;
 152                if (sctp_cacc_skip_3_1_f(transport, count_of_newacks))
 153                        return 1;
 154                return 0;
 155        }
 156        return 0;
 157}
 158
 159/*
 160 * SFR-CACC algorithm:
 161 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less
 162 * than next_tsn_at_change of the current primary, then
 163 * the sender MUST NOT increment missing report count
 164 * for t.
 165 */
 166static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn)
 167{
 168        if (primary->cacc.cycling_changeover &&
 169            TSN_lt(tsn, primary->cacc.next_tsn_at_change))
 170                return 1;
 171        return 0;
 172}
 173
 174/*
 175 * SFR-CACC algorithm:
 176 * 3) If the missing report count for TSN t is to be
 177 * incremented according to [RFC2960] and
 178 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set,
 179 * then the sender MUST futher execute steps 3.1 and
 180 * 3.2 to determine if the missing report count for
 181 * TSN t SHOULD NOT be incremented.
 182 *
 183 * 3.3) If 3.1 and 3.2 do not dictate that the missing
 184 * report count for t should not be incremented, then
 185 * the sender SOULD increment missing report count for
 186 * t (according to [RFC2960] and [SCTP_STEWART_2002]).
 187 */
 188static inline int sctp_cacc_skip(struct sctp_transport *primary,
 189                                 struct sctp_transport *transport,
 190                                 int count_of_newacks,
 191                                 __u32 tsn)
 192{
 193        if (primary->cacc.changeover_active &&
 194            (sctp_cacc_skip_3_1(primary, transport, count_of_newacks)
 195             || sctp_cacc_skip_3_2(primary, tsn)))
 196                return 1;
 197        return 0;
 198}
 199
 200/* Initialize an existing sctp_outq.  This does the boring stuff.
 201 * You still need to define handlers if you really want to DO
 202 * something with this structure...
 203 */
 204void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q)
 205{
 206        q->asoc = asoc;
 207        INIT_LIST_HEAD(&q->out_chunk_list);
 208        INIT_LIST_HEAD(&q->control_chunk_list);
 209        INIT_LIST_HEAD(&q->retransmit);
 210        INIT_LIST_HEAD(&q->sacked);
 211        INIT_LIST_HEAD(&q->abandoned);
 212
 213        q->fast_rtx = 0;
 214        q->outstanding_bytes = 0;
 215        q->empty = 1;
 216        q->cork  = 0;
 217
 218        q->malloced = 0;
 219        q->out_qlen = 0;
 220}
 221
 222/* Free the outqueue structure and any related pending chunks.
 223 */
 224void sctp_outq_teardown(struct sctp_outq *q)
 225{
 226        struct sctp_transport *transport;
 227        struct list_head *lchunk, *temp;
 228        struct sctp_chunk *chunk, *tmp;
 229
 230        /* Throw away unacknowledged chunks. */
 231        list_for_each_entry(transport, &q->asoc->peer.transport_addr_list,
 232                        transports) {
 233                while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) {
 234                        chunk = list_entry(lchunk, struct sctp_chunk,
 235                                           transmitted_list);
 236                        /* Mark as part of a failed message. */
 237                        sctp_chunk_fail(chunk, q->error);
 238                        sctp_chunk_free(chunk);
 239                }
 240        }
 241
 242        /* Throw away chunks that have been gap ACKed.  */
 243        list_for_each_safe(lchunk, temp, &q->sacked) {
 244                list_del_init(lchunk);
 245                chunk = list_entry(lchunk, struct sctp_chunk,
 246                                   transmitted_list);
 247                sctp_chunk_fail(chunk, q->error);
 248                sctp_chunk_free(chunk);
 249        }
 250
 251        /* Throw away any chunks in the retransmit queue. */
 252        list_for_each_safe(lchunk, temp, &q->retransmit) {
 253                list_del_init(lchunk);
 254                chunk = list_entry(lchunk, struct sctp_chunk,
 255                                   transmitted_list);
 256                sctp_chunk_fail(chunk, q->error);
 257                sctp_chunk_free(chunk);
 258        }
 259
 260        /* Throw away any chunks that are in the abandoned queue. */
 261        list_for_each_safe(lchunk, temp, &q->abandoned) {
 262                list_del_init(lchunk);
 263                chunk = list_entry(lchunk, struct sctp_chunk,
 264                                   transmitted_list);
 265                sctp_chunk_fail(chunk, q->error);
 266                sctp_chunk_free(chunk);
 267        }
 268
 269        /* Throw away any leftover data chunks. */
 270        while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
 271
 272                /* Mark as send failure. */
 273                sctp_chunk_fail(chunk, q->error);
 274                sctp_chunk_free(chunk);
 275        }
 276
 277        q->error = 0;
 278
 279        /* Throw away any leftover control chunks. */
 280        list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
 281                list_del_init(&chunk->list);
 282                sctp_chunk_free(chunk);
 283        }
 284}
 285
 286/* Free the outqueue structure and any related pending chunks.  */
 287void sctp_outq_free(struct sctp_outq *q)
 288{
 289        /* Throw away leftover chunks. */
 290        sctp_outq_teardown(q);
 291
 292        /* If we were kmalloc()'d, free the memory.  */
 293        if (q->malloced)
 294                kfree(q);
 295}
 296
 297/* Put a new chunk in an sctp_outq.  */
 298int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk)
 299{
 300        int error = 0;
 301
 302        SCTP_DEBUG_PRINTK("sctp_outq_tail(%p, %p[%s])\n",
 303                          q, chunk, chunk && chunk->chunk_hdr ?
 304                          sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type))
 305                          : "Illegal Chunk");
 306
 307        /* If it is data, queue it up, otherwise, send it
 308         * immediately.
 309         */
 310        if (SCTP_CID_DATA == chunk->chunk_hdr->type) {
 311                /* Is it OK to queue data chunks?  */
 312                /* From 9. Termination of Association
 313                 *
 314                 * When either endpoint performs a shutdown, the
 315                 * association on each peer will stop accepting new
 316                 * data from its user and only deliver data in queue
 317                 * at the time of sending or receiving the SHUTDOWN
 318                 * chunk.
 319                 */
 320                switch (q->asoc->state) {
 321                case SCTP_STATE_EMPTY:
 322                case SCTP_STATE_CLOSED:
 323                case SCTP_STATE_SHUTDOWN_PENDING:
 324                case SCTP_STATE_SHUTDOWN_SENT:
 325                case SCTP_STATE_SHUTDOWN_RECEIVED:
 326                case SCTP_STATE_SHUTDOWN_ACK_SENT:
 327                        /* Cannot send after transport endpoint shutdown */
 328                        error = -ESHUTDOWN;
 329                        break;
 330
 331                default:
 332                        SCTP_DEBUG_PRINTK("outqueueing (%p, %p[%s])\n",
 333                          q, chunk, chunk && chunk->chunk_hdr ?
 334                          sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type))
 335                          : "Illegal Chunk");
 336
 337                        sctp_outq_tail_data(q, chunk);
 338                        if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
 339                                SCTP_INC_STATS(SCTP_MIB_OUTUNORDERCHUNKS);
 340                        else
 341                                SCTP_INC_STATS(SCTP_MIB_OUTORDERCHUNKS);
 342                        q->empty = 0;
 343                        break;
 344                }
 345        } else {
 346                list_add_tail(&chunk->list, &q->control_chunk_list);
 347                SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
 348        }
 349
 350        if (error < 0)
 351                return error;
 352
 353        if (!q->cork)
 354                error = sctp_outq_flush(q, 0);
 355
 356        return error;
 357}
 358
 359/* Insert a chunk into the sorted list based on the TSNs.  The retransmit list
 360 * and the abandoned list are in ascending order.
 361 */
 362static void sctp_insert_list(struct list_head *head, struct list_head *new)
 363{
 364        struct list_head *pos;
 365        struct sctp_chunk *nchunk, *lchunk;
 366        __u32 ntsn, ltsn;
 367        int done = 0;
 368
 369        nchunk = list_entry(new, struct sctp_chunk, transmitted_list);
 370        ntsn = ntohl(nchunk->subh.data_hdr->tsn);
 371
 372        list_for_each(pos, head) {
 373                lchunk = list_entry(pos, struct sctp_chunk, transmitted_list);
 374                ltsn = ntohl(lchunk->subh.data_hdr->tsn);
 375                if (TSN_lt(ntsn, ltsn)) {
 376                        list_add(new, pos->prev);
 377                        done = 1;
 378                        break;
 379                }
 380        }
 381        if (!done)
 382                list_add_tail(new, head);
 383}
 384
 385/* Mark all the eligible packets on a transport for retransmission.  */
 386void sctp_retransmit_mark(struct sctp_outq *q,
 387                          struct sctp_transport *transport,
 388                          __u8 reason)
 389{
 390        struct list_head *lchunk, *ltemp;
 391        struct sctp_chunk *chunk;
 392
 393        /* Walk through the specified transmitted queue.  */
 394        list_for_each_safe(lchunk, ltemp, &transport->transmitted) {
 395                chunk = list_entry(lchunk, struct sctp_chunk,
 396                                   transmitted_list);
 397
 398                /* If the chunk is abandoned, move it to abandoned list. */
 399                if (sctp_chunk_abandoned(chunk)) {
 400                        list_del_init(lchunk);
 401                        sctp_insert_list(&q->abandoned, lchunk);
 402
 403                        /* If this chunk has not been previousely acked,
 404                         * stop considering it 'outstanding'.  Our peer
 405                         * will most likely never see it since it will
 406                         * not be retransmitted
 407                         */
 408                        if (!chunk->tsn_gap_acked) {
 409                                chunk->transport->flight_size -=
 410                                                sctp_data_size(chunk);
 411                                q->outstanding_bytes -= sctp_data_size(chunk);
 412                                q->asoc->peer.rwnd += (sctp_data_size(chunk) +
 413                                                        sizeof(struct sk_buff));
 414                        }
 415                        continue;
 416                }
 417
 418                /* If we are doing  retransmission due to a timeout or pmtu
 419                 * discovery, only the  chunks that are not yet acked should
 420                 * be added to the retransmit queue.
 421                 */
 422                if ((reason == SCTP_RTXR_FAST_RTX  &&
 423                            (chunk->fast_retransmit == SCTP_NEED_FRTX)) ||
 424                    (reason != SCTP_RTXR_FAST_RTX  && !chunk->tsn_gap_acked)) {
 425                        /* If this chunk was sent less then 1 rto ago, do not
 426                         * retransmit this chunk, but give the peer time
 427                         * to acknowlege it.  Do this only when
 428                         * retransmitting due to T3 timeout.
 429                         */
 430                        if (reason == SCTP_RTXR_T3_RTX &&
 431                            time_before(jiffies, chunk->sent_at +
 432                                                 transport->last_rto))
 433                                continue;
 434
 435                        /* RFC 2960 6.2.1 Processing a Received SACK
 436                         *
 437                         * C) Any time a DATA chunk is marked for
 438                         * retransmission (via either T3-rtx timer expiration
 439                         * (Section 6.3.3) or via fast retransmit
 440                         * (Section 7.2.4)), add the data size of those
 441                         * chunks to the rwnd.
 442                         */
 443                        q->asoc->peer.rwnd += (sctp_data_size(chunk) +
 444                                                sizeof(struct sk_buff));
 445                        q->outstanding_bytes -= sctp_data_size(chunk);
 446                        transport->flight_size -= sctp_data_size(chunk);
 447
 448                        /* sctpimpguide-05 Section 2.8.2
 449                         * M5) If a T3-rtx timer expires, the
 450                         * 'TSN.Missing.Report' of all affected TSNs is set
 451                         * to 0.
 452                         */
 453                        chunk->tsn_missing_report = 0;
 454
 455                        /* If a chunk that is being used for RTT measurement
 456                         * has to be retransmitted, we cannot use this chunk
 457                         * anymore for RTT measurements. Reset rto_pending so
 458                         * that a new RTT measurement is started when a new
 459                         * data chunk is sent.
 460                         */
 461                        if (chunk->rtt_in_progress) {
 462                                chunk->rtt_in_progress = 0;
 463                                transport->rto_pending = 0;
 464                        }
 465
 466                        /* Move the chunk to the retransmit queue. The chunks
 467                         * on the retransmit queue are always kept in order.
 468                         */
 469                        list_del_init(lchunk);
 470                        sctp_insert_list(&q->retransmit, lchunk);
 471                }
 472        }
 473
 474        SCTP_DEBUG_PRINTK("%s: transport: %p, reason: %d, "
 475                          "cwnd: %d, ssthresh: %d, flight_size: %d, "
 476                          "pba: %d\n", __func__,
 477                          transport, reason,
 478                          transport->cwnd, transport->ssthresh,
 479                          transport->flight_size,
 480                          transport->partial_bytes_acked);
 481
 482}
 483
 484/* Mark all the eligible packets on a transport for retransmission and force
 485 * one packet out.
 486 */
 487void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
 488                     sctp_retransmit_reason_t reason)
 489{
 490        int error = 0;
 491
 492        switch(reason) {
 493        case SCTP_RTXR_T3_RTX:
 494                SCTP_INC_STATS(SCTP_MIB_T3_RETRANSMITS);
 495                sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX);
 496                /* Update the retran path if the T3-rtx timer has expired for
 497                 * the current retran path.
 498                 */
 499                if (transport == transport->asoc->peer.retran_path)
 500                        sctp_assoc_update_retran_path(transport->asoc);
 501                transport->asoc->rtx_data_chunks +=
 502                        transport->asoc->unack_data;
 503                break;
 504        case SCTP_RTXR_FAST_RTX:
 505                SCTP_INC_STATS(SCTP_MIB_FAST_RETRANSMITS);
 506                sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX);
 507                q->fast_rtx = 1;
 508                break;
 509        case SCTP_RTXR_PMTUD:
 510                SCTP_INC_STATS(SCTP_MIB_PMTUD_RETRANSMITS);
 511                break;
 512        case SCTP_RTXR_T1_RTX:
 513                SCTP_INC_STATS(SCTP_MIB_T1_RETRANSMITS);
 514                transport->asoc->init_retries++;
 515                break;
 516        default:
 517                BUG();
 518        }
 519
 520        sctp_retransmit_mark(q, transport, reason);
 521
 522        /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
 523         * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
 524         * following the procedures outlined in C1 - C5.
 525         */
 526        if (reason == SCTP_RTXR_T3_RTX)
 527                sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point);
 528
 529        /* Flush the queues only on timeout, since fast_rtx is only
 530         * triggered during sack processing and the queue
 531         * will be flushed at the end.
 532         */
 533        if (reason != SCTP_RTXR_FAST_RTX)
 534                error = sctp_outq_flush(q, /* rtx_timeout */ 1);
 535
 536        if (error)
 537                q->asoc->base.sk->sk_err = -error;
 538}
 539
 540/*
 541 * Transmit DATA chunks on the retransmit queue.  Upon return from
 542 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
 543 * need to be transmitted by the caller.
 544 * We assume that pkt->transport has already been set.
 545 *
 546 * The return value is a normal kernel error return value.
 547 */
 548static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
 549                               int rtx_timeout, int *start_timer)
 550{
 551        struct list_head *lqueue;
 552        struct sctp_transport *transport = pkt->transport;
 553        sctp_xmit_t status;
 554        struct sctp_chunk *chunk, *chunk1;
 555        struct sctp_association *asoc;
 556        int fast_rtx;
 557        int error = 0;
 558        int timer = 0;
 559        int done = 0;
 560
 561        asoc = q->asoc;
 562        lqueue = &q->retransmit;
 563        fast_rtx = q->fast_rtx;
 564
 565        /* This loop handles time-out retransmissions, fast retransmissions,
 566         * and retransmissions due to opening of whindow.
 567         *
 568         * RFC 2960 6.3.3 Handle T3-rtx Expiration
 569         *
 570         * E3) Determine how many of the earliest (i.e., lowest TSN)
 571         * outstanding DATA chunks for the address for which the
 572         * T3-rtx has expired will fit into a single packet, subject
 573         * to the MTU constraint for the path corresponding to the
 574         * destination transport address to which the retransmission
 575         * is being sent (this may be different from the address for
 576         * which the timer expires [see Section 6.4]). Call this value
 577         * K. Bundle and retransmit those K DATA chunks in a single
 578         * packet to the destination endpoint.
 579         *
 580         * [Just to be painfully clear, if we are retransmitting
 581         * because a timeout just happened, we should send only ONE
 582         * packet of retransmitted data.]
 583         *
 584         * For fast retransmissions we also send only ONE packet.  However,
 585         * if we are just flushing the queue due to open window, we'll
 586         * try to send as much as possible.
 587         */
 588        list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) {
 589
 590                /* Make sure that Gap Acked TSNs are not retransmitted.  A
 591                 * simple approach is just to move such TSNs out of the
 592                 * way and into a 'transmitted' queue and skip to the
 593                 * next chunk.
 594                 */
 595                if (chunk->tsn_gap_acked) {
 596                        list_del(&chunk->transmitted_list);
 597                        list_add_tail(&chunk->transmitted_list,
 598                                        &transport->transmitted);
 599                        continue;
 600                }
 601
 602                /* If we are doing fast retransmit, ignore non-fast_rtransmit
 603                 * chunks
 604                 */
 605                if (fast_rtx && !chunk->fast_retransmit)
 606                        continue;
 607
 608                /* Attempt to append this chunk to the packet. */
 609                status = sctp_packet_append_chunk(pkt, chunk);
 610
 611                switch (status) {
 612                case SCTP_XMIT_PMTU_FULL:
 613                        /* Send this packet.  */
 614                        error = sctp_packet_transmit(pkt);
 615
 616                        /* If we are retransmitting, we should only
 617                         * send a single packet.
 618                         */
 619                        if (rtx_timeout || fast_rtx)
 620                                done = 1;
 621
 622                        /* Bundle next chunk in the next round.  */
 623                        break;
 624
 625                case SCTP_XMIT_RWND_FULL:
 626                        /* Send this packet. */
 627                        error = sctp_packet_transmit(pkt);
 628
 629                        /* Stop sending DATA as there is no more room
 630                         * at the receiver.
 631                         */
 632                        done = 1;
 633                        break;
 634
 635                case SCTP_XMIT_NAGLE_DELAY:
 636                        /* Send this packet. */
 637                        error = sctp_packet_transmit(pkt);
 638
 639                        /* Stop sending DATA because of nagle delay. */
 640                        done = 1;
 641                        break;
 642
 643                default:
 644                        /* The append was successful, so add this chunk to
 645                         * the transmitted list.
 646                         */
 647                        list_del(&chunk->transmitted_list);
 648                        list_add_tail(&chunk->transmitted_list,
 649                                        &transport->transmitted);
 650
 651                        /* Mark the chunk as ineligible for fast retransmit
 652                         * after it is retransmitted.
 653                         */
 654                        if (chunk->fast_retransmit == SCTP_NEED_FRTX)
 655                                chunk->fast_retransmit = SCTP_DONT_FRTX;
 656
 657                        /* Force start T3-rtx timer when fast retransmitting
 658                         * the earliest outstanding TSN
 659                         */
 660                        if (!timer && fast_rtx &&
 661                            ntohl(chunk->subh.data_hdr->tsn) ==
 662                                             asoc->ctsn_ack_point + 1)
 663                                timer = 2;
 664
 665                        q->empty = 0;
 666                        break;
 667                }
 668
 669                /* Set the timer if there were no errors */
 670                if (!error && !timer)
 671                        timer = 1;
 672
 673                if (done)
 674                        break;
 675        }
 676
 677        /* If we are here due to a retransmit timeout or a fast
 678         * retransmit and if there are any chunks left in the retransmit
 679         * queue that could not fit in the PMTU sized packet, they need
 680         * to be marked as ineligible for a subsequent fast retransmit.
 681         */
 682        if (rtx_timeout || fast_rtx) {
 683                list_for_each_entry(chunk1, lqueue, transmitted_list) {
 684                        if (chunk1->fast_retransmit == SCTP_NEED_FRTX)
 685                                chunk1->fast_retransmit = SCTP_DONT_FRTX;
 686                }
 687        }
 688
 689        *start_timer = timer;
 690
 691        /* Clear fast retransmit hint */
 692        if (fast_rtx)
 693                q->fast_rtx = 0;
 694
 695        return error;
 696}
 697
 698/* Cork the outqueue so queued chunks are really queued. */
 699int sctp_outq_uncork(struct sctp_outq *q)
 700{
 701        int error = 0;
 702        if (q->cork)
 703                q->cork = 0;
 704        error = sctp_outq_flush(q, 0);
 705        return error;
 706}
 707
 708
 709/*
 710 * Try to flush an outqueue.
 711 *
 712 * Description: Send everything in q which we legally can, subject to
 713 * congestion limitations.
 714 * * Note: This function can be called from multiple contexts so appropriate
 715 * locking concerns must be made.  Today we use the sock lock to protect
 716 * this function.
 717 */
 718static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
 719{
 720        struct sctp_packet *packet;
 721        struct sctp_packet singleton;
 722        struct sctp_association *asoc = q->asoc;
 723        __u16 sport = asoc->base.bind_addr.port;
 724        __u16 dport = asoc->peer.port;
 725        __u32 vtag = asoc->peer.i.init_tag;
 726        struct sctp_transport *transport = NULL;
 727        struct sctp_transport *new_transport;
 728        struct sctp_chunk *chunk, *tmp;
 729        sctp_xmit_t status;
 730        int error = 0;
 731        int start_timer = 0;
 732        int one_packet = 0;
 733
 734        /* These transports have chunks to send. */
 735        struct list_head transport_list;
 736        struct list_head *ltransport;
 737
 738        INIT_LIST_HEAD(&transport_list);
 739        packet = NULL;
 740
 741        /*
 742         * 6.10 Bundling
 743         *   ...
 744         *   When bundling control chunks with DATA chunks, an
 745         *   endpoint MUST place control chunks first in the outbound
 746         *   SCTP packet.  The transmitter MUST transmit DATA chunks
 747         *   within a SCTP packet in increasing order of TSN.
 748         *   ...
 749         */
 750
 751        list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
 752                list_del_init(&chunk->list);
 753
 754                /* Pick the right transport to use. */
 755                new_transport = chunk->transport;
 756
 757                if (!new_transport) {
 758                        /*
 759                         * If we have a prior transport pointer, see if
 760                         * the destination address of the chunk
 761                         * matches the destination address of the
 762                         * current transport.  If not a match, then
 763                         * try to look up the transport with a given
 764                         * destination address.  We do this because
 765                         * after processing ASCONFs, we may have new
 766                         * transports created.
 767                         */
 768                        if (transport &&
 769                            sctp_cmp_addr_exact(&chunk->dest,
 770                                                &transport->ipaddr))
 771                                        new_transport = transport;
 772                        else
 773                                new_transport = sctp_assoc_lookup_paddr(asoc,
 774                                                                &chunk->dest);
 775
 776                        /* if we still don't have a new transport, then
 777                         * use the current active path.
 778                         */
 779                        if (!new_transport)
 780                                new_transport = asoc->peer.active_path;
 781                } else if ((new_transport->state == SCTP_INACTIVE) ||
 782                           (new_transport->state == SCTP_UNCONFIRMED)) {
 783                        /* If the chunk is Heartbeat or Heartbeat Ack,
 784                         * send it to chunk->transport, even if it's
 785                         * inactive.
 786                         *
 787                         * 3.3.6 Heartbeat Acknowledgement:
 788                         * ...
 789                         * A HEARTBEAT ACK is always sent to the source IP
 790                         * address of the IP datagram containing the
 791                         * HEARTBEAT chunk to which this ack is responding.
 792                         * ...
 793                         *
 794                         * ASCONF_ACKs also must be sent to the source.
 795                         */
 796                        if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT &&
 797                            chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK &&
 798                            chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK)
 799                                new_transport = asoc->peer.active_path;
 800                }
 801
 802                /* Are we switching transports?
 803                 * Take care of transport locks.
 804                 */
 805                if (new_transport != transport) {
 806                        transport = new_transport;
 807                        if (list_empty(&transport->send_ready)) {
 808                                list_add_tail(&transport->send_ready,
 809                                              &transport_list);
 810                        }
 811                        packet = &transport->packet;
 812                        sctp_packet_config(packet, vtag,
 813                                           asoc->peer.ecn_capable);
 814                }
 815
 816                switch (chunk->chunk_hdr->type) {
 817                /*
 818                 * 6.10 Bundling
 819                 *   ...
 820                 *   An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
 821                 *   COMPLETE with any other chunks.  [Send them immediately.]
 822                 */
 823                case SCTP_CID_INIT:
 824                case SCTP_CID_INIT_ACK:
 825                case SCTP_CID_SHUTDOWN_COMPLETE:
 826                        sctp_packet_init(&singleton, transport, sport, dport);
 827                        sctp_packet_config(&singleton, vtag, 0);
 828                        sctp_packet_append_chunk(&singleton, chunk);
 829                        error = sctp_packet_transmit(&singleton);
 830                        if (error < 0)
 831                                return error;
 832                        break;
 833
 834                case SCTP_CID_ABORT:
 835                        if (sctp_test_T_bit(chunk)) {
 836                                packet->vtag = asoc->c.my_vtag;
 837                        }
 838                /* The following chunks are "response" chunks, i.e.
 839                 * they are generated in response to something we
 840                 * received.  If we are sending these, then we can
 841                 * send only 1 packet containing these chunks.
 842                 */
 843                case SCTP_CID_HEARTBEAT_ACK:
 844                case SCTP_CID_SHUTDOWN_ACK:
 845                case SCTP_CID_COOKIE_ACK:
 846                case SCTP_CID_COOKIE_ECHO:
 847                case SCTP_CID_ERROR:
 848                case SCTP_CID_ECN_CWR:
 849                case SCTP_CID_ASCONF_ACK:
 850                        one_packet = 1;
 851                        /* Fall throught */
 852
 853                case SCTP_CID_SACK:
 854                case SCTP_CID_HEARTBEAT:
 855                case SCTP_CID_SHUTDOWN:
 856                case SCTP_CID_ECN_ECNE:
 857                case SCTP_CID_ASCONF:
 858                case SCTP_CID_FWD_TSN:
 859                        status = sctp_packet_transmit_chunk(packet, chunk,
 860                                                            one_packet);
 861                        if (status  != SCTP_XMIT_OK) {
 862                                /* put the chunk back */
 863                                list_add(&chunk->list, &q->control_chunk_list);
 864                        }
 865                        break;
 866
 867                default:
 868                        /* We built a chunk with an illegal type! */
 869                        BUG();
 870                }
 871        }
 872
 873        /* Is it OK to send data chunks?  */
 874        switch (asoc->state) {
 875        case SCTP_STATE_COOKIE_ECHOED:
 876                /* Only allow bundling when this packet has a COOKIE-ECHO
 877                 * chunk.
 878                 */
 879                if (!packet || !packet->has_cookie_echo)
 880                        break;
 881
 882                /* fallthru */
 883        case SCTP_STATE_ESTABLISHED:
 884        case SCTP_STATE_SHUTDOWN_PENDING:
 885        case SCTP_STATE_SHUTDOWN_RECEIVED:
 886                /*
 887                 * RFC 2960 6.1  Transmission of DATA Chunks
 888                 *
 889                 * C) When the time comes for the sender to transmit,
 890                 * before sending new DATA chunks, the sender MUST
 891                 * first transmit any outstanding DATA chunks which
 892                 * are marked for retransmission (limited by the
 893                 * current cwnd).
 894                 */
 895                if (!list_empty(&q->retransmit)) {
 896                        if (transport == asoc->peer.retran_path)
 897                                goto retran;
 898
 899                        /* Switch transports & prepare the packet.  */
 900
 901                        transport = asoc->peer.retran_path;
 902
 903                        if (list_empty(&transport->send_ready)) {
 904                                list_add_tail(&transport->send_ready,
 905                                              &transport_list);
 906                        }
 907
 908                        packet = &transport->packet;
 909                        sctp_packet_config(packet, vtag,
 910                                           asoc->peer.ecn_capable);
 911                retran:
 912                        error = sctp_outq_flush_rtx(q, packet,
 913                                                    rtx_timeout, &start_timer);
 914
 915                        if (start_timer)
 916                                sctp_transport_reset_timers(transport,
 917                                                            start_timer-1);
 918
 919                        /* This can happen on COOKIE-ECHO resend.  Only
 920                         * one chunk can get bundled with a COOKIE-ECHO.
 921                         */
 922                        if (packet->has_cookie_echo)
 923                                goto sctp_flush_out;
 924
 925                        /* Don't send new data if there is still data
 926                         * waiting to retransmit.
 927                         */
 928                        if (!list_empty(&q->retransmit))
 929                                goto sctp_flush_out;
 930                }
 931
 932                /* Finally, transmit new packets.  */
 933                while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
 934                        /* RFC 2960 6.5 Every DATA chunk MUST carry a valid
 935                         * stream identifier.
 936                         */
 937                        if (chunk->sinfo.sinfo_stream >=
 938                            asoc->c.sinit_num_ostreams) {
 939
 940                                /* Mark as failed send. */
 941                                sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM);
 942                                sctp_chunk_free(chunk);
 943                                continue;
 944                        }
 945
 946                        /* Has this chunk expired? */
 947                        if (sctp_chunk_abandoned(chunk)) {
 948                                sctp_chunk_fail(chunk, 0);
 949                                sctp_chunk_free(chunk);
 950                                continue;
 951                        }
 952
 953                        /* If there is a specified transport, use it.
 954                         * Otherwise, we want to use the active path.
 955                         */
 956                        new_transport = chunk->transport;
 957                        if (!new_transport ||
 958                            ((new_transport->state == SCTP_INACTIVE) ||
 959                             (new_transport->state == SCTP_UNCONFIRMED)))
 960                                new_transport = asoc->peer.active_path;
 961
 962                        /* Change packets if necessary.  */
 963                        if (new_transport != transport) {
 964                                transport = new_transport;
 965
 966                                /* Schedule to have this transport's
 967                                 * packet flushed.
 968                                 */
 969                                if (list_empty(&transport->send_ready)) {
 970                                        list_add_tail(&transport->send_ready,
 971                                                      &transport_list);
 972                                }
 973
 974                                packet = &transport->packet;
 975                                sctp_packet_config(packet, vtag,
 976                                                   asoc->peer.ecn_capable);
 977                        }
 978
 979                        SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ",
 980                                          q, chunk,
 981                                          chunk && chunk->chunk_hdr ?
 982                                          sctp_cname(SCTP_ST_CHUNK(
 983                                                  chunk->chunk_hdr->type))
 984                                          : "Illegal Chunk");
 985
 986                        SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head "
 987                                        "%p skb->users %d.\n",
 988                                        ntohl(chunk->subh.data_hdr->tsn),
 989                                        chunk->skb ?chunk->skb->head : NULL,
 990                                        chunk->skb ?
 991                                        atomic_read(&chunk->skb->users) : -1);
 992
 993                        /* Add the chunk to the packet.  */
 994                        status = sctp_packet_transmit_chunk(packet, chunk, 0);
 995
 996                        switch (status) {
 997                        case SCTP_XMIT_PMTU_FULL:
 998                        case SCTP_XMIT_RWND_FULL:
 999                        case SCTP_XMIT_NAGLE_DELAY:
1000                                /* We could not append this chunk, so put
1001                                 * the chunk back on the output queue.
1002                                 */
1003                                SCTP_DEBUG_PRINTK("sctp_outq_flush: could "
1004                                        "not transmit TSN: 0x%x, status: %d\n",
1005                                        ntohl(chunk->subh.data_hdr->tsn),
1006                                        status);
1007                                sctp_outq_head_data(q, chunk);
1008                                goto sctp_flush_out;
1009                                break;
1010
1011                        case SCTP_XMIT_OK:
1012                                break;
1013
1014                        default:
1015                                BUG();
1016                        }
1017
1018                        /* BUG: We assume that the sctp_packet_transmit()
1019                         * call below will succeed all the time and add the
1020                         * chunk to the transmitted list and restart the
1021                         * timers.
1022                         * It is possible that the call can fail under OOM
1023                         * conditions.
1024                         *
1025                         * Is this really a problem?  Won't this behave
1026                         * like a lost TSN?
1027                         */
1028                        list_add_tail(&chunk->transmitted_list,
1029                                      &transport->transmitted);
1030
1031                        sctp_transport_reset_timers(transport, 0);
1032
1033                        q->empty = 0;
1034
1035                        /* Only let one DATA chunk get bundled with a
1036                         * COOKIE-ECHO chunk.
1037                         */
1038                        if (packet->has_cookie_echo)
1039                                goto sctp_flush_out;
1040                }
1041                break;
1042
1043        default:
1044                /* Do nothing.  */
1045                break;
1046        }
1047
1048sctp_flush_out:
1049
1050        /* Before returning, examine all the transports touched in
1051         * this call.  Right now, we bluntly force clear all the
1052         * transports.  Things might change after we implement Nagle.
1053         * But such an examination is still required.
1054         *
1055         * --xguo
1056         */
1057        while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) {
1058                struct sctp_transport *t = list_entry(ltransport,
1059                                                      struct sctp_transport,
1060                                                      send_ready);
1061                packet = &t->packet;
1062                if (!sctp_packet_empty(packet))
1063                        error = sctp_packet_transmit(packet);
1064        }
1065
1066        return error;
1067}
1068
1069/* Update unack_data based on the incoming SACK chunk */
1070static void sctp_sack_update_unack_data(struct sctp_association *assoc,
1071                                        struct sctp_sackhdr *sack)
1072{
1073        sctp_sack_variable_t *frags;
1074        __u16 unack_data;
1075        int i;
1076
1077        unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1;
1078
1079        frags = sack->variable;
1080        for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) {
1081                unack_data -= ((ntohs(frags[i].gab.end) -
1082                                ntohs(frags[i].gab.start) + 1));
1083        }
1084
1085        assoc->unack_data = unack_data;
1086}
1087
1088/* Return the highest new tsn that is acknowledged by the given SACK chunk. */
1089static __u32 sctp_highest_new_tsn(struct sctp_sackhdr *sack,
1090                                  struct sctp_association *asoc)
1091{
1092        struct sctp_transport *transport;
1093        struct sctp_chunk *chunk;
1094        __u32 highest_new_tsn, tsn;
1095        struct list_head *transport_list = &asoc->peer.transport_addr_list;
1096
1097        highest_new_tsn = ntohl(sack->cum_tsn_ack);
1098
1099        list_for_each_entry(transport, transport_list, transports) {
1100                list_for_each_entry(chunk, &transport->transmitted,
1101                                transmitted_list) {
1102                        tsn = ntohl(chunk->subh.data_hdr->tsn);
1103
1104                        if (!chunk->tsn_gap_acked &&
1105                            TSN_lt(highest_new_tsn, tsn) &&
1106                            sctp_acked(sack, tsn))
1107                                highest_new_tsn = tsn;
1108                }
1109        }
1110
1111        return highest_new_tsn;
1112}
1113
1114/* This is where we REALLY process a SACK.
1115 *
1116 * Process the SACK against the outqueue.  Mostly, this just frees
1117 * things off the transmitted queue.
1118 */
1119int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack)
1120{
1121        struct sctp_association *asoc = q->asoc;
1122        struct sctp_transport *transport;
1123        struct sctp_chunk *tchunk = NULL;
1124        struct list_head *lchunk, *transport_list, *temp;
1125        sctp_sack_variable_t *frags = sack->variable;
1126        __u32 sack_ctsn, ctsn, tsn;
1127        __u32 highest_tsn, highest_new_tsn;
1128        __u32 sack_a_rwnd;
1129        unsigned outstanding;
1130        struct sctp_transport *primary = asoc->peer.primary_path;
1131        int count_of_newacks = 0;
1132        int gap_ack_blocks;
1133
1134        /* Grab the association's destination address list. */
1135        transport_list = &asoc->peer.transport_addr_list;
1136
1137        sack_ctsn = ntohl(sack->cum_tsn_ack);
1138        gap_ack_blocks = ntohs(sack->num_gap_ack_blocks);
1139        /*
1140         * SFR-CACC algorithm:
1141         * On receipt of a SACK the sender SHOULD execute the
1142         * following statements.
1143         *
1144         * 1) If the cumulative ack in the SACK passes next tsn_at_change
1145         * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1146         * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1147         * all destinations.
1148         * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1149         * is set the receiver of the SACK MUST take the following actions:
1150         *
1151         * A) Initialize the cacc_saw_newack to 0 for all destination
1152         * addresses.
1153         *
1154         * Only bother if changeover_active is set. Otherwise, this is
1155         * totally suboptimal to do on every SACK.
1156         */
1157        if (primary->cacc.changeover_active) {
1158                u8 clear_cycling = 0;
1159
1160                if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) {
1161                        primary->cacc.changeover_active = 0;
1162                        clear_cycling = 1;
1163                }
1164
1165                if (clear_cycling || gap_ack_blocks) {
1166                        list_for_each_entry(transport, transport_list,
1167                                        transports) {
1168                                if (clear_cycling)
1169                                        transport->cacc.cycling_changeover = 0;
1170                                if (gap_ack_blocks)
1171                                        transport->cacc.cacc_saw_newack = 0;
1172                        }
1173                }
1174        }
1175
1176        /* Get the highest TSN in the sack. */
1177        highest_tsn = sack_ctsn;
1178        if (gap_ack_blocks)
1179                highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end);
1180
1181        if (TSN_lt(asoc->highest_sacked, highest_tsn)) {
1182                highest_new_tsn = highest_tsn;
1183                asoc->highest_sacked = highest_tsn;
1184        } else {
1185                highest_new_tsn = sctp_highest_new_tsn(sack, asoc);
1186        }
1187
1188
1189        /* Run through the retransmit queue.  Credit bytes received
1190         * and free those chunks that we can.
1191         */
1192        sctp_check_transmitted(q, &q->retransmit, NULL, sack, highest_new_tsn);
1193
1194        /* Run through the transmitted queue.
1195         * Credit bytes received and free those chunks which we can.
1196         *
1197         * This is a MASSIVE candidate for optimization.
1198         */
1199        list_for_each_entry(transport, transport_list, transports) {
1200                sctp_check_transmitted(q, &transport->transmitted,
1201                                       transport, sack, highest_new_tsn);
1202                /*
1203                 * SFR-CACC algorithm:
1204                 * C) Let count_of_newacks be the number of
1205                 * destinations for which cacc_saw_newack is set.
1206                 */
1207                if (transport->cacc.cacc_saw_newack)
1208                        count_of_newacks ++;
1209        }
1210
1211        if (gap_ack_blocks) {
1212                list_for_each_entry(transport, transport_list, transports)
1213                        sctp_mark_missing(q, &transport->transmitted, transport,
1214                                          highest_new_tsn, count_of_newacks);
1215        }
1216
1217        /* Move the Cumulative TSN Ack Point if appropriate.  */
1218        if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn))
1219                asoc->ctsn_ack_point = sack_ctsn;
1220
1221        /* Update unack_data field in the assoc. */
1222        sctp_sack_update_unack_data(asoc, sack);
1223
1224        ctsn = asoc->ctsn_ack_point;
1225
1226        /* Throw away stuff rotting on the sack queue.  */
1227        list_for_each_safe(lchunk, temp, &q->sacked) {
1228                tchunk = list_entry(lchunk, struct sctp_chunk,
1229                                    transmitted_list);
1230                tsn = ntohl(tchunk->subh.data_hdr->tsn);
1231                if (TSN_lte(tsn, ctsn)) {
1232                        list_del_init(&tchunk->transmitted_list);
1233                        sctp_chunk_free(tchunk);
1234                }
1235        }
1236
1237        /* ii) Set rwnd equal to the newly received a_rwnd minus the
1238         *     number of bytes still outstanding after processing the
1239         *     Cumulative TSN Ack and the Gap Ack Blocks.
1240         */
1241
1242        sack_a_rwnd = ntohl(sack->a_rwnd);
1243        outstanding = q->outstanding_bytes;
1244
1245        if (outstanding < sack_a_rwnd)
1246                sack_a_rwnd -= outstanding;
1247        else
1248                sack_a_rwnd = 0;
1249
1250        asoc->peer.rwnd = sack_a_rwnd;
1251
1252        sctp_generate_fwdtsn(q, sack_ctsn);
1253
1254        SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n",
1255                          __func__, sack_ctsn);
1256        SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, "
1257                          "%p is 0x%x. Adv peer ack point: 0x%x\n",
1258                          __func__, asoc, ctsn, asoc->adv_peer_ack_point);
1259
1260        /* See if all chunks are acked.
1261         * Make sure the empty queue handler will get run later.
1262         */
1263        q->empty = (list_empty(&q->out_chunk_list) &&
1264                    list_empty(&q->retransmit));
1265        if (!q->empty)
1266                goto finish;
1267
1268        list_for_each_entry(transport, transport_list, transports) {
1269                q->empty = q->empty && list_empty(&transport->transmitted);
1270                if (!q->empty)
1271                        goto finish;
1272        }
1273
1274        SCTP_DEBUG_PRINTK("sack queue is empty.\n");
1275finish:
1276        return q->empty;
1277}
1278
1279/* Is the outqueue empty?  */
1280int sctp_outq_is_empty(const struct sctp_outq *q)
1281{
1282        return q->empty;
1283}
1284
1285/********************************************************************
1286 * 2nd Level Abstractions
1287 ********************************************************************/
1288
1289/* Go through a transport's transmitted list or the association's retransmit
1290 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1291 * The retransmit list will not have an associated transport.
1292 *
1293 * I added coherent debug information output.   --xguo
1294 *
1295 * Instead of printing 'sacked' or 'kept' for each TSN on the
1296 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1297 * KEPT TSN6-TSN7, etc.
1298 */
1299static void sctp_check_transmitted(struct sctp_outq *q,
1300                                   struct list_head *transmitted_queue,
1301                                   struct sctp_transport *transport,
1302                                   struct sctp_sackhdr *sack,
1303                                   __u32 highest_new_tsn_in_sack)
1304{
1305        struct list_head *lchunk;
1306        struct sctp_chunk *tchunk;
1307        struct list_head tlist;
1308        __u32 tsn;
1309        __u32 sack_ctsn;
1310        __u32 rtt;
1311        __u8 restart_timer = 0;
1312        int bytes_acked = 0;
1313
1314        /* These state variables are for coherent debug output. --xguo */
1315
1316#if SCTP_DEBUG
1317        __u32 dbg_ack_tsn = 0;  /* An ACKed TSN range starts here... */
1318        __u32 dbg_last_ack_tsn = 0;  /* ...and finishes here.        */
1319        __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here...  */
1320        __u32 dbg_last_kept_tsn = 0; /* ...and finishes here.        */
1321
1322        /* 0 : The last TSN was ACKed.
1323         * 1 : The last TSN was NOT ACKed (i.e. KEPT).
1324         * -1: We need to initialize.
1325         */
1326        int dbg_prt_state = -1;
1327#endif /* SCTP_DEBUG */
1328
1329        sack_ctsn = ntohl(sack->cum_tsn_ack);
1330
1331        INIT_LIST_HEAD(&tlist);
1332
1333        /* The while loop will skip empty transmitted queues. */
1334        while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) {
1335                tchunk = list_entry(lchunk, struct sctp_chunk,
1336                                    transmitted_list);
1337
1338                if (sctp_chunk_abandoned(tchunk)) {
1339                        /* Move the chunk to abandoned list. */
1340                        sctp_insert_list(&q->abandoned, lchunk);
1341
1342                        /* If this chunk has not been acked, stop
1343                         * considering it as 'outstanding'.
1344                         */
1345                        if (!tchunk->tsn_gap_acked) {
1346                                tchunk->transport->flight_size -=
1347                                                sctp_data_size(tchunk);
1348                                q->outstanding_bytes -= sctp_data_size(tchunk);
1349                        }
1350                        continue;
1351                }
1352
1353                tsn = ntohl(tchunk->subh.data_hdr->tsn);
1354                if (sctp_acked(sack, tsn)) {
1355                        /* If this queue is the retransmit queue, the
1356                         * retransmit timer has already reclaimed
1357                         * the outstanding bytes for this chunk, so only
1358                         * count bytes associated with a transport.
1359                         */
1360                        if (transport) {
1361                                /* If this chunk is being used for RTT
1362                                 * measurement, calculate the RTT and update
1363                                 * the RTO using this value.
1364                                 *
1365                                 * 6.3.1 C5) Karn's algorithm: RTT measurements
1366                                 * MUST NOT be made using packets that were
1367                                 * retransmitted (and thus for which it is
1368                                 * ambiguous whether the reply was for the
1369                                 * first instance of the packet or a later
1370                                 * instance).
1371                                 */
1372                                if (!tchunk->tsn_gap_acked &&
1373                                    !tchunk->resent &&
1374                                    tchunk->rtt_in_progress) {
1375                                        tchunk->rtt_in_progress = 0;
1376                                        rtt = jiffies - tchunk->sent_at;
1377                                        sctp_transport_update_rto(transport,
1378                                                                  rtt);
1379                                }
1380                        }
1381                        if (TSN_lte(tsn, sack_ctsn)) {
1382                                /* RFC 2960  6.3.2 Retransmission Timer Rules
1383                                 *
1384                                 * R3) Whenever a SACK is received
1385                                 * that acknowledges the DATA chunk
1386                                 * with the earliest outstanding TSN
1387                                 * for that address, restart T3-rtx
1388                                 * timer for that address with its
1389                                 * current RTO.
1390                                 */
1391                                restart_timer = 1;
1392
1393                                if (!tchunk->tsn_gap_acked) {
1394                                        tchunk->tsn_gap_acked = 1;
1395                                        bytes_acked += sctp_data_size(tchunk);
1396                                        /*
1397                                         * SFR-CACC algorithm:
1398                                         * 2) If the SACK contains gap acks
1399                                         * and the flag CHANGEOVER_ACTIVE is
1400                                         * set the receiver of the SACK MUST
1401                                         * take the following action:
1402                                         *
1403                                         * B) For each TSN t being acked that
1404                                         * has not been acked in any SACK so
1405                                         * far, set cacc_saw_newack to 1 for
1406                                         * the destination that the TSN was
1407                                         * sent to.
1408                                         */
1409                                        if (transport &&
1410                                            sack->num_gap_ack_blocks &&
1411                                            q->asoc->peer.primary_path->cacc.
1412                                            changeover_active)
1413                                                transport->cacc.cacc_saw_newack
1414                                                        = 1;
1415                                }
1416
1417                                list_add_tail(&tchunk->transmitted_list,
1418                                              &q->sacked);
1419                        } else {
1420                                /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1421                                 * M2) Each time a SACK arrives reporting
1422                                 * 'Stray DATA chunk(s)' record the highest TSN
1423                                 * reported as newly acknowledged, call this
1424                                 * value 'HighestTSNinSack'. A newly
1425                                 * acknowledged DATA chunk is one not
1426                                 * previously acknowledged in a SACK.
1427                                 *
1428                                 * When the SCTP sender of data receives a SACK
1429                                 * chunk that acknowledges, for the first time,
1430                                 * the receipt of a DATA chunk, all the still
1431                                 * unacknowledged DATA chunks whose TSN is
1432                                 * older than that newly acknowledged DATA
1433                                 * chunk, are qualified as 'Stray DATA chunks'.
1434                                 */
1435                                if (!tchunk->tsn_gap_acked) {
1436                                        tchunk->tsn_gap_acked = 1;
1437                                        bytes_acked += sctp_data_size(tchunk);
1438                                }
1439                                list_add_tail(lchunk, &tlist);
1440                        }
1441
1442#if SCTP_DEBUG
1443                        switch (dbg_prt_state) {
1444                        case 0: /* last TSN was ACKed */
1445                                if (dbg_last_ack_tsn + 1 == tsn) {
1446                                        /* This TSN belongs to the
1447                                         * current ACK range.
1448                                         */
1449                                        break;
1450                                }
1451
1452                                if (dbg_last_ack_tsn != dbg_ack_tsn) {
1453                                        /* Display the end of the
1454                                         * current range.
1455                                         */
1456                                        SCTP_DEBUG_PRINTK("-%08x",
1457                                                          dbg_last_ack_tsn);
1458                                }
1459
1460                                /* Start a new range.  */
1461                                SCTP_DEBUG_PRINTK(",%08x", tsn);
1462                                dbg_ack_tsn = tsn;
1463                                break;
1464
1465                        case 1: /* The last TSN was NOT ACKed. */
1466                                if (dbg_last_kept_tsn != dbg_kept_tsn) {
1467                                        /* Display the end of current range. */
1468                                        SCTP_DEBUG_PRINTK("-%08x",
1469                                                          dbg_last_kept_tsn);
1470                                }
1471
1472                                SCTP_DEBUG_PRINTK("\n");
1473
1474                                /* FALL THROUGH... */
1475                        default:
1476                                /* This is the first-ever TSN we examined.  */
1477                                /* Start a new range of ACK-ed TSNs.  */
1478                                SCTP_DEBUG_PRINTK("ACKed: %08x", tsn);
1479                                dbg_prt_state = 0;
1480                                dbg_ack_tsn = tsn;
1481                        }
1482
1483                        dbg_last_ack_tsn = tsn;
1484#endif /* SCTP_DEBUG */
1485
1486                } else {
1487                        if (tchunk->tsn_gap_acked) {
1488                                SCTP_DEBUG_PRINTK("%s: Receiver reneged on "
1489                                                  "data TSN: 0x%x\n",
1490                                                  __func__,
1491                                                  tsn);
1492                                tchunk->tsn_gap_acked = 0;
1493
1494                                bytes_acked -= sctp_data_size(tchunk);
1495
1496                                /* RFC 2960 6.3.2 Retransmission Timer Rules
1497                                 *
1498                                 * R4) Whenever a SACK is received missing a
1499                                 * TSN that was previously acknowledged via a
1500                                 * Gap Ack Block, start T3-rtx for the
1501                                 * destination address to which the DATA
1502                                 * chunk was originally
1503                                 * transmitted if it is not already running.
1504                                 */
1505                                restart_timer = 1;
1506                        }
1507
1508                        list_add_tail(lchunk, &tlist);
1509
1510#if SCTP_DEBUG
1511                        /* See the above comments on ACK-ed TSNs. */
1512                        switch (dbg_prt_state) {
1513                        case 1:
1514                                if (dbg_last_kept_tsn + 1 == tsn)
1515                                        break;
1516
1517                                if (dbg_last_kept_tsn != dbg_kept_tsn)
1518                                        SCTP_DEBUG_PRINTK("-%08x",
1519                                                          dbg_last_kept_tsn);
1520
1521                                SCTP_DEBUG_PRINTK(",%08x", tsn);
1522                                dbg_kept_tsn = tsn;
1523                                break;
1524
1525                        case 0:
1526                                if (dbg_last_ack_tsn != dbg_ack_tsn)
1527                                        SCTP_DEBUG_PRINTK("-%08x",
1528                                                          dbg_last_ack_tsn);
1529                                SCTP_DEBUG_PRINTK("\n");
1530
1531                                /* FALL THROUGH... */
1532                        default:
1533                                SCTP_DEBUG_PRINTK("KEPT: %08x",tsn);
1534                                dbg_prt_state = 1;
1535                                dbg_kept_tsn = tsn;
1536                        }
1537
1538                        dbg_last_kept_tsn = tsn;
1539#endif /* SCTP_DEBUG */
1540                }
1541        }
1542
1543#if SCTP_DEBUG
1544        /* Finish off the last range, displaying its ending TSN.  */
1545        switch (dbg_prt_state) {
1546        case 0:
1547                if (dbg_last_ack_tsn != dbg_ack_tsn) {
1548                        SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn);
1549                } else {
1550                        SCTP_DEBUG_PRINTK("\n");
1551                }
1552        break;
1553
1554        case 1:
1555                if (dbg_last_kept_tsn != dbg_kept_tsn) {
1556                        SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn);
1557                } else {
1558                        SCTP_DEBUG_PRINTK("\n");
1559                }
1560        }
1561#endif /* SCTP_DEBUG */
1562        if (transport) {
1563                if (bytes_acked) {
1564                        /* 8.2. When an outstanding TSN is acknowledged,
1565                         * the endpoint shall clear the error counter of
1566                         * the destination transport address to which the
1567                         * DATA chunk was last sent.
1568                         * The association's overall error counter is
1569                         * also cleared.
1570                         */
1571                        transport->error_count = 0;
1572                        transport->asoc->overall_error_count = 0;
1573
1574                        /* Mark the destination transport address as
1575                         * active if it is not so marked.
1576                         */
1577                        if ((transport->state == SCTP_INACTIVE) ||
1578                            (transport->state == SCTP_UNCONFIRMED)) {
1579                                sctp_assoc_control_transport(
1580                                        transport->asoc,
1581                                        transport,
1582                                        SCTP_TRANSPORT_UP,
1583                                        SCTP_RECEIVED_SACK);
1584                        }
1585
1586                        sctp_transport_raise_cwnd(transport, sack_ctsn,
1587                                                  bytes_acked);
1588
1589                        transport->flight_size -= bytes_acked;
1590                        if (transport->flight_size == 0)
1591                                transport->partial_bytes_acked = 0;
1592                        q->outstanding_bytes -= bytes_acked;
1593                } else {
1594                        /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1595                         * When a sender is doing zero window probing, it
1596                         * should not timeout the association if it continues
1597                         * to receive new packets from the receiver. The
1598                         * reason is that the receiver MAY keep its window
1599                         * closed for an indefinite time.
1600                         * A sender is doing zero window probing when the
1601                         * receiver's advertised window is zero, and there is
1602                         * only one data chunk in flight to the receiver.
1603                         */
1604                        if (!q->asoc->peer.rwnd &&
1605                            !list_empty(&tlist) &&
1606                            (sack_ctsn+2 == q->asoc->next_tsn)) {
1607                                SCTP_DEBUG_PRINTK("%s: SACK received for zero "
1608                                                  "window probe: %u\n",
1609                                                  __func__, sack_ctsn);
1610                                q->asoc->overall_error_count = 0;
1611                                transport->error_count = 0;
1612                        }
1613                }
1614
1615                /* RFC 2960 6.3.2 Retransmission Timer Rules
1616                 *
1617                 * R2) Whenever all outstanding data sent to an address have
1618                 * been acknowledged, turn off the T3-rtx timer of that
1619                 * address.
1620                 */
1621                if (!transport->flight_size) {
1622                        if (timer_pending(&transport->T3_rtx_timer) &&
1623                            del_timer(&transport->T3_rtx_timer)) {
1624                                sctp_transport_put(transport);
1625                        }
1626                } else if (restart_timer) {
1627                        if (!mod_timer(&transport->T3_rtx_timer,
1628                                       jiffies + transport->rto))
1629                                sctp_transport_hold(transport);
1630                }
1631        }
1632
1633        list_splice(&tlist, transmitted_queue);
1634}
1635
1636/* Mark chunks as missing and consequently may get retransmitted. */
1637static void sctp_mark_missing(struct sctp_outq *q,
1638                              struct list_head *transmitted_queue,
1639                              struct sctp_transport *transport,
1640                              __u32 highest_new_tsn_in_sack,
1641                              int count_of_newacks)
1642{
1643        struct sctp_chunk *chunk;
1644        __u32 tsn;
1645        char do_fast_retransmit = 0;
1646        struct sctp_transport *primary = q->asoc->peer.primary_path;
1647
1648        list_for_each_entry(chunk, transmitted_queue, transmitted_list) {
1649
1650                tsn = ntohl(chunk->subh.data_hdr->tsn);
1651
1652                /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1653                 * 'Unacknowledged TSN's', if the TSN number of an
1654                 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1655                 * value, increment the 'TSN.Missing.Report' count on that
1656                 * chunk if it has NOT been fast retransmitted or marked for
1657                 * fast retransmit already.
1658                 */
1659                if (chunk->fast_retransmit == SCTP_CAN_FRTX &&
1660                    !chunk->tsn_gap_acked &&
1661                    TSN_lt(tsn, highest_new_tsn_in_sack)) {
1662
1663                        /* SFR-CACC may require us to skip marking
1664                         * this chunk as missing.
1665                         */
1666                        if (!transport || !sctp_cacc_skip(primary, transport,
1667                                            count_of_newacks, tsn)) {
1668                                chunk->tsn_missing_report++;
1669
1670                                SCTP_DEBUG_PRINTK(
1671                                        "%s: TSN 0x%x missing counter: %d\n",
1672                                        __func__, tsn,
1673                                        chunk->tsn_missing_report);
1674                        }
1675                }
1676                /*
1677                 * M4) If any DATA chunk is found to have a
1678                 * 'TSN.Missing.Report'
1679                 * value larger than or equal to 3, mark that chunk for
1680                 * retransmission and start the fast retransmit procedure.
1681                 */
1682
1683                if (chunk->tsn_missing_report >= 3) {
1684                        chunk->fast_retransmit = SCTP_NEED_FRTX;
1685                        do_fast_retransmit = 1;
1686                }
1687        }
1688
1689        if (transport) {
1690                if (do_fast_retransmit)
1691                        sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX);
1692
1693                SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, "
1694                                  "ssthresh: %d, flight_size: %d, pba: %d\n",
1695                                  __func__, transport, transport->cwnd,
1696                                  transport->ssthresh, transport->flight_size,
1697                                  transport->partial_bytes_acked);
1698        }
1699}
1700
1701/* Is the given TSN acked by this packet?  */
1702static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
1703{
1704        int i;
1705        sctp_sack_variable_t *frags;
1706        __u16 gap;
1707        __u32 ctsn = ntohl(sack->cum_tsn_ack);
1708
1709        if (TSN_lte(tsn, ctsn))
1710                goto pass;
1711
1712        /* 3.3.4 Selective Acknowledgement (SACK) (3):
1713         *
1714         * Gap Ack Blocks:
1715         *  These fields contain the Gap Ack Blocks. They are repeated
1716         *  for each Gap Ack Block up to the number of Gap Ack Blocks
1717         *  defined in the Number of Gap Ack Blocks field. All DATA
1718         *  chunks with TSNs greater than or equal to (Cumulative TSN
1719         *  Ack + Gap Ack Block Start) and less than or equal to
1720         *  (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1721         *  Block are assumed to have been received correctly.
1722         */
1723
1724        frags = sack->variable;
1725        gap = tsn - ctsn;
1726        for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) {
1727                if (TSN_lte(ntohs(frags[i].gab.start), gap) &&
1728                    TSN_lte(gap, ntohs(frags[i].gab.end)))
1729                        goto pass;
1730        }
1731
1732        return 0;
1733pass:
1734        return 1;
1735}
1736
1737static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist,
1738                                    int nskips, __be16 stream)
1739{
1740        int i;
1741
1742        for (i = 0; i < nskips; i++) {
1743                if (skiplist[i].stream == stream)
1744                        return i;
1745        }
1746        return i;
1747}
1748
1749/* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1750static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn)
1751{
1752        struct sctp_association *asoc = q->asoc;
1753        struct sctp_chunk *ftsn_chunk = NULL;
1754        struct sctp_fwdtsn_skip ftsn_skip_arr[10];
1755        int nskips = 0;
1756        int skip_pos = 0;
1757        __u32 tsn;
1758        struct sctp_chunk *chunk;
1759        struct list_head *lchunk, *temp;
1760
1761        if (!asoc->peer.prsctp_capable)
1762                return;
1763
1764        /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1765         * received SACK.
1766         *
1767         * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1768         * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1769         */
1770        if (TSN_lt(asoc->adv_peer_ack_point, ctsn))
1771                asoc->adv_peer_ack_point = ctsn;
1772
1773        /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1774         * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1775         * the chunk next in the out-queue space is marked as "abandoned" as
1776         * shown in the following example:
1777         *
1778         * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1779         * and the Advanced.Peer.Ack.Point is updated to this value:
1780         *
1781         *   out-queue at the end of  ==>   out-queue after Adv.Ack.Point
1782         *   normal SACK processing           local advancement
1783         *                ...                           ...
1784         *   Adv.Ack.Pt-> 102 acked                     102 acked
1785         *                103 abandoned                 103 abandoned
1786         *                104 abandoned     Adv.Ack.P-> 104 abandoned
1787         *                105                           105
1788         *                106 acked                     106 acked
1789         *                ...                           ...
1790         *
1791         * In this example, the data sender successfully advanced the
1792         * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1793         */
1794        list_for_each_safe(lchunk, temp, &q->abandoned) {
1795                chunk = list_entry(lchunk, struct sctp_chunk,
1796                                        transmitted_list);
1797                tsn = ntohl(chunk->subh.data_hdr->tsn);
1798
1799                /* Remove any chunks in the abandoned queue that are acked by
1800                 * the ctsn.
1801                 */
1802                if (TSN_lte(tsn, ctsn)) {
1803                        list_del_init(lchunk);
1804                        sctp_chunk_free(chunk);
1805                } else {
1806                        if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) {
1807                                asoc->adv_peer_ack_point = tsn;
1808                                if (chunk->chunk_hdr->flags &
1809                                         SCTP_DATA_UNORDERED)
1810                                        continue;
1811                                skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0],
1812                                                nskips,
1813                                                chunk->subh.data_hdr->stream);
1814                                ftsn_skip_arr[skip_pos].stream =
1815                                        chunk->subh.data_hdr->stream;
1816                                ftsn_skip_arr[skip_pos].ssn =
1817                                         chunk->subh.data_hdr->ssn;
1818                                if (skip_pos == nskips)
1819                                        nskips++;
1820                                if (nskips == 10)
1821                                        break;
1822                        } else
1823                                break;
1824                }
1825        }
1826
1827        /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1828         * is greater than the Cumulative TSN ACK carried in the received
1829         * SACK, the data sender MUST send the data receiver a FORWARD TSN
1830         * chunk containing the latest value of the
1831         * "Advanced.Peer.Ack.Point".
1832         *
1833         * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1834         * list each stream and sequence number in the forwarded TSN. This
1835         * information will enable the receiver to easily find any
1836         * stranded TSN's waiting on stream reorder queues. Each stream
1837         * SHOULD only be reported once; this means that if multiple
1838         * abandoned messages occur in the same stream then only the
1839         * highest abandoned stream sequence number is reported. If the
1840         * total size of the FORWARD TSN does NOT fit in a single MTU then
1841         * the sender of the FORWARD TSN SHOULD lower the
1842         * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1843         * single MTU.
1844         */
1845        if (asoc->adv_peer_ack_point > ctsn)
1846                ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point,
1847                                              nskips, &ftsn_skip_arr[0]);
1848
1849        if (ftsn_chunk) {
1850                list_add_tail(&ftsn_chunk->list, &q->control_chunk_list);
1851                SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
1852        }
1853}
1854