sys/netinet/sctp_cc_functions.c

   1 /*-
   2  * Copyright (c) 2001-2007, by Cisco Systems, Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are met:
   6  *
   7  * a) Redistributions of source code must retain the above copyright notice,
   8  *   this list of conditions and the following disclaimer.
   9  *
  10  * b) Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in
  12  *   the documentation and/or other materials provided with the distribution.
  13  *
  14  * c) Neither the name of Cisco Systems, Inc. nor the names of its
  15  *    contributors may be used to endorse or promote products derived
  16  *    from this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  20  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  22  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  28  * THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #include <netinet/sctp_os.h>
  32 #include <netinet/sctp_var.h>
  33 #include <netinet/sctp_sysctl.h>
  34 #include <netinet/sctp_pcb.h>
  35 #include <netinet/sctp_header.h>
  36 #include <netinet/sctputil.h>
  37 #include <netinet/sctp_output.h>
  38 #include <netinet/sctp_input.h>
  39 #include <netinet/sctp_indata.h>
  40 #include <netinet/sctp_uio.h>
  41 #include <netinet/sctp_timer.h>
  42 #include <netinet/sctp_auth.h>
  43 #include <netinet/sctp_asconf.h>
  44 #include <netinet/sctp_cc_functions.h>
  45 #include <sys/cdefs.h>
  46 __FBSDID("$FreeBSD$");
  47
  48 void
  49 sctp_set_initial_cc_param(struct sctp_tcb *stcb, struct sctp_nets *net)
  50 {
  51         struct sctp_association *assoc;
  52         uint32_t cwnd_in_mtu;
  53
  54         assoc = &stcb->asoc;
  55         /*
  56          * We take the minimum of the burst limit and the initial congestion
  57          * window. The initial congestion window is at least two times the
  58          * MTU.
  59          */
  60         cwnd_in_mtu = SCTP_BASE_SYSCTL(sctp_initial_cwnd);
  61         if ((assoc->max_burst > 0) && (cwnd_in_mtu > assoc->max_burst))
  62                 cwnd_in_mtu = assoc->max_burst;
  63         net->cwnd = (net->mtu - sizeof(struct sctphdr)) * cwnd_in_mtu;
  64         net->ssthresh = assoc->peers_rwnd;
  65
  66         if (SCTP_BASE_SYSCTL(sctp_logging_level) &
  67             (SCTP_CWND_MONITOR_ENABLE | SCTP_CWND_LOGGING_ENABLE)) {
  68                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_INITIALIZATION);
  69         }
  70 }
  71
  72 void
  73 sctp_cwnd_update_after_fr(struct sctp_tcb *stcb,
  74     struct sctp_association *asoc)
  75 {
  76         struct sctp_nets *net;
  77
  78         /*-
  79          * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off == 1) &&
  80          * (net->fast_retran_loss_recovery == 0)))
  81          */
  82         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
  83                 if ((asoc->fast_retran_loss_recovery == 0) ||
  84                     (asoc->sctp_cmt_on_off == 1)) {
  85                         /* out of a RFC2582 Fast recovery window? */
  86                         if (net->net_ack > 0) {
  87                                 /*
  88                                  * per section 7.2.3, are there any
  89                                  * destinations that had a fast retransmit
  90                                  * to them. If so what we need to do is
  91                                  * adjust ssthresh and cwnd.
  92                                  */
  93                                 struct sctp_tmit_chunk *lchk;
  94                                 int old_cwnd = net->cwnd;
  95
  96                                 net->ssthresh = net->cwnd / 2;
  97                                 if (net->ssthresh < (net->mtu * 2)) {
  98                                         net->ssthresh = 2 * net->mtu;
  99                                 }
 100                                 net->cwnd = net->ssthresh;
 101                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 102                                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
 103                                             SCTP_CWND_LOG_FROM_FR);
 104                                 }
 105                                 lchk = TAILQ_FIRST(&asoc->send_queue);
 106
 107                                 net->partial_bytes_acked = 0;
 108                                 /* Turn on fast recovery window */
 109                                 asoc->fast_retran_loss_recovery = 1;
 110                                 if (lchk == NULL) {
 111                                         /* Mark end of the window */
 112                                         asoc->fast_recovery_tsn = asoc->sending_seq - 1;
 113                                 } else {
 114                                         asoc->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
 115                                 }
 116
 117                                 /*
 118                                  * CMT fast recovery -- per destination
 119                                  * recovery variable.
 120                                  */
 121                                 net->fast_retran_loss_recovery = 1;
 122
 123                                 if (lchk == NULL) {
 124                                         /* Mark end of the window */
 125                                         net->fast_recovery_tsn = asoc->sending_seq - 1;
 126                                 } else {
 127                                         net->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
 128                                 }
 129
 130                                 /*
 131                                  * Disable Nonce Sum Checking and store the
 132                                  * resync tsn
 133                                  */
 134                                 asoc->nonce_sum_check = 0;
 135                                 asoc->nonce_resync_tsn = asoc->fast_recovery_tsn + 1;
 136
 137                                 sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
 138                                     stcb->sctp_ep, stcb, net, SCTP_FROM_SCTP_INDATA + SCTP_LOC_32);
 139                                 sctp_timer_start(SCTP_TIMER_TYPE_SEND,
 140                                     stcb->sctp_ep, stcb, net);
 141                         }
 142                 } else if (net->net_ack > 0) {
 143                         /*
 144                          * Mark a peg that we WOULD have done a cwnd
 145                          * reduction but RFC2582 prevented this action.
 146                          */
 147                         SCTP_STAT_INCR(sctps_fastretransinrtt);
 148                 }
 149         }
 150 }
 151
 152 void
 153 sctp_cwnd_update_after_sack(struct sctp_tcb *stcb,
 154     struct sctp_association *asoc,
 155     int accum_moved, int reneged_all, int will_exit)
 156 {
 157         struct sctp_nets *net;
 158
 159         /******************************/
 160         /* update cwnd and Early FR   */
 161         /******************************/
 162         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
 163
 164 #ifdef JANA_CMT_FAST_RECOVERY
 165                 /*
 166                  * CMT fast recovery code. Need to debug.
 167                  */
 168                 if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
 169                         if (compare_with_wrap(asoc->last_acked_seq,
 170                             net->fast_recovery_tsn, MAX_TSN) ||
 171                             (asoc->last_acked_seq == net->fast_recovery_tsn) ||
 172                             compare_with_wrap(net->pseudo_cumack, net->fast_recovery_tsn, MAX_TSN) ||
 173                             (net->pseudo_cumack == net->fast_recovery_tsn)) {
 174                                 net->will_exit_fast_recovery = 1;
 175                         }
 176                 }
 177 #endif
 178                 if (SCTP_BASE_SYSCTL(sctp_early_fr)) {
 179                         /*
 180                          * So, first of all do we need to have a Early FR
 181                          * timer running?
 182                          */
 183                         if ((!TAILQ_EMPTY(&asoc->sent_queue) &&
 184                             (net->ref_count > 1) &&
 185                             (net->flight_size < net->cwnd)) ||
 186                             (reneged_all)) {
 187                                 /*
 188                                  * yes, so in this case stop it if its
 189                                  * running, and then restart it. Reneging
 190                                  * all is a special case where we want to
 191                                  * run the Early FR timer and then force the
 192                                  * last few unacked to be sent, causing us
 193                                  * to illicit a sack with gaps to force out
 194                                  * the others.
 195                                  */
 196                                 if (SCTP_OS_TIMER_PENDING(&net->fr_timer.timer)) {
 197                                         SCTP_STAT_INCR(sctps_earlyfrstpidsck2);
 198                                         sctp_timer_stop(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net,
 199                                             SCTP_FROM_SCTP_INDATA + SCTP_LOC_20);
 200                                 }
 201                                 SCTP_STAT_INCR(sctps_earlyfrstrid);
 202                                 sctp_timer_start(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net);
 203                         } else {
 204                                 /* No, stop it if its running */
 205                                 if (SCTP_OS_TIMER_PENDING(&net->fr_timer.timer)) {
 206                                         SCTP_STAT_INCR(sctps_earlyfrstpidsck3);
 207                                         sctp_timer_stop(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net,
 208                                             SCTP_FROM_SCTP_INDATA + SCTP_LOC_21);
 209                                 }
 210                         }
 211                 }
 212                 /* if nothing was acked on this destination skip it */
 213                 if (net->net_ack == 0) {
 214                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 215                                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
 216                         }
 217                         continue;
 218                 }
 219                 if (net->net_ack2 > 0) {
 220                         /*
 221                          * Karn's rule applies to clearing error count, this
 222                          * is optional.
 223                          */
 224                         net->error_count = 0;
 225                         if ((net->dest_state & SCTP_ADDR_NOT_REACHABLE) ==
 226                             SCTP_ADDR_NOT_REACHABLE) {
 227                                 /* addr came good */
 228                                 net->dest_state &= ~SCTP_ADDR_NOT_REACHABLE;
 229                                 net->dest_state |= SCTP_ADDR_REACHABLE;
 230                                 sctp_ulp_notify(SCTP_NOTIFY_INTERFACE_UP, stcb,
 231                                     SCTP_RECEIVED_SACK, (void *)net, SCTP_SO_NOT_LOCKED);
 232                                 /* now was it the primary? if so restore */
 233                                 if (net->dest_state & SCTP_ADDR_WAS_PRIMARY) {
 234                                         (void)sctp_set_primary_addr(stcb, (struct sockaddr *)NULL, net);
 235                                 }
 236                         }
 237                         /*
 238                          * JRS 5/14/07 - If CMT PF is on and the destination
 239                          * is in PF state, set the destination to active
 240                          * state and set the cwnd to one or two MTU's based
 241                          * on whether PF1 or PF2 is being used.
 242                          *
 243                          * Should we stop any running T3 timer here?
 244                          */
 245                         if ((asoc->sctp_cmt_on_off == 1) &&
 246                             (asoc->sctp_cmt_pf > 0) &&
 247                             ((net->dest_state & SCTP_ADDR_PF) == SCTP_ADDR_PF)) {
 248                                 net->dest_state &= ~SCTP_ADDR_PF;
 249                                 net->cwnd = net->mtu * asoc->sctp_cmt_pf;
 250                                 SCTPDBG(SCTP_DEBUG_INDATA1, "Destination %p moved from PF to reachable with cwnd %d.\n",
 251                                     net, net->cwnd);
 252                                 /*
 253                                  * Since the cwnd value is explicitly set,
 254                                  * skip the code that updates the cwnd
 255                                  * value.
 256                                  */
 257                                 goto skip_cwnd_update;
 258                         }
 259                 }
 260 #ifdef JANA_CMT_FAST_RECOVERY
 261                 /*
 262                  * CMT fast recovery code
 263                  */
 264                 /*
 265                  * if (sctp_cmt_on_off == 1 &&
 266                  * net->fast_retran_loss_recovery &&
 267                  * net->will_exit_fast_recovery == 0) { @@@ Do something }
 268                  * else if (sctp_cmt_on_off == 0 &&
 269                  * asoc->fast_retran_loss_recovery && will_exit == 0) {
 270                  */
 271 #endif
 272
 273                 if (asoc->fast_retran_loss_recovery &&
 274                     (will_exit == 0) &&
 275                     (asoc->sctp_cmt_on_off == 0)) {
 276                         /*
 277                          * If we are in loss recovery we skip any cwnd
 278                          * update
 279                          */
 280                         goto skip_cwnd_update;
 281                 }
 282                 /*
 283                  * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
 284                  * moved.
 285                  */
 286                 if (accum_moved ||
 287                     ((asoc->sctp_cmt_on_off == 1) && net->new_pseudo_cumack)) {
 288                         /* If the cumulative ack moved we can proceed */
 289                         if (net->cwnd <= net->ssthresh) {
 290                                 /* We are in slow start */
 291                                 if (net->flight_size + net->net_ack >= net->cwnd) {
 292                                         if (net->net_ack > (net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable))) {
 293                                                 net->cwnd += (net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable));
 294                                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 295                                                         sctp_log_cwnd(stcb, net, net->mtu,
 296                                                             SCTP_CWND_LOG_FROM_SS);
 297                                                 }
 298                                         } else {
 299                                                 net->cwnd += net->net_ack;
 300                                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 301                                                         sctp_log_cwnd(stcb, net, net->net_ack,
 302                                                             SCTP_CWND_LOG_FROM_SS);
 303                                                 }
 304                                         }
 305                                 } else {
 306                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 307                                                 sctp_log_cwnd(stcb, net, net->net_ack,
 308                                                     SCTP_CWND_LOG_NOADV_SS);
 309                                         }
 310                                 }
 311                         } else {
 312                                 /* We are in congestion avoidance */
 313                                 /*
 314                                  * Add to pba
 315                                  */
 316                                 net->partial_bytes_acked += net->net_ack;
 317
 318                                 if ((net->flight_size + net->net_ack >= net->cwnd) &&
 319                                     (net->partial_bytes_acked >= net->cwnd)) {
 320                                         net->partial_bytes_acked -= net->cwnd;
 321                                         net->cwnd += net->mtu;
 322                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 323                                                 sctp_log_cwnd(stcb, net, net->mtu,
 324                                                     SCTP_CWND_LOG_FROM_CA);
 325                                         }
 326                                 } else {
 327                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 328                                                 sctp_log_cwnd(stcb, net, net->net_ack,
 329                                                     SCTP_CWND_LOG_NOADV_CA);
 330                                         }
 331                                 }
 332                         }
 333                 } else {
 334                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 335                                 sctp_log_cwnd(stcb, net, net->mtu,
 336                                     SCTP_CWND_LOG_NO_CUMACK);
 337                         }
 338                 }
 339 skip_cwnd_update:
 340                 /*
 341                  * NOW, according to Karn's rule do we need to restore the
 342                  * RTO timer back? Check our net_ack2. If not set then we
 343                  * have a ambiguity.. i.e. all data ack'd was sent to more
 344                  * than one place.
 345                  */
 346                 if (net->net_ack2) {
 347                         /* restore any doubled timers */
 348                         net->RTO = ((net->lastsa >> 2) + net->lastsv) >> 1;
 349                         if (net->RTO < stcb->asoc.minrto) {
 350                                 net->RTO = stcb->asoc.minrto;
 351                         }
 352                         if (net->RTO > stcb->asoc.maxrto) {
 353                                 net->RTO = stcb->asoc.maxrto;
 354                         }
 355                 }
 356         }
 357 }
 358
 359 void
 360 sctp_cwnd_update_after_timeout(struct sctp_tcb *stcb, struct sctp_nets *net)
 361 {
 362         int old_cwnd = net->cwnd;
 363
 364         net->ssthresh = max(net->cwnd / 2, 4 * net->mtu);
 365         net->cwnd = net->mtu;
 366         net->partial_bytes_acked = 0;
 367
 368         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 369                 sctp_log_cwnd(stcb, net, net->cwnd - old_cwnd, SCTP_CWND_LOG_FROM_RTX);
 370         }
 371 }
 372
 373 void
 374 sctp_cwnd_update_after_ecn_echo(struct sctp_tcb *stcb, struct sctp_nets *net)
 375 {
 376         int old_cwnd = net->cwnd;
 377
 378         SCTP_STAT_INCR(sctps_ecnereducedcwnd);
 379         net->ssthresh = net->cwnd / 2;
 380         if (net->ssthresh < net->mtu) {
 381                 net->ssthresh = net->mtu;
 382                 /* here back off the timer as well, to slow us down */
 383                 net->RTO <<= 1;
 384         }
 385         net->cwnd = net->ssthresh;
 386         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 387                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
 388         }
 389 }
 390
 391 void
 392 sctp_cwnd_update_after_packet_dropped(struct sctp_tcb *stcb,
 393     struct sctp_nets *net, struct sctp_pktdrop_chunk *cp,
 394     uint32_t * bottle_bw, uint32_t * on_queue)
 395 {
 396         uint32_t bw_avail;
 397         int rtt, incr;
 398         int old_cwnd = net->cwnd;
 399
 400         /* need real RTT for this calc */
 401         rtt = ((net->lastsa >> 2) + net->lastsv) >> 1;
 402         /* get bottle neck bw */
 403         *bottle_bw = ntohl(cp->bottle_bw);
 404         /* and whats on queue */
 405         *on_queue = ntohl(cp->current_onq);
 406         /*
 407          * adjust the on-queue if our flight is more it could be that the
 408          * router has not yet gotten data "in-flight" to it
 409          */
 410         if (*on_queue < net->flight_size)
 411                 *on_queue = net->flight_size;
 412         /* calculate the available space */
 413         bw_avail = (*bottle_bw * rtt) / 1000;
 414         if (bw_avail > *bottle_bw) {
 415                 /*
 416                  * Cap the growth to no more than the bottle neck. This can
 417                  * happen as RTT slides up due to queues. It also means if
 418                  * you have more than a 1 second RTT with a empty queue you
 419                  * will be limited to the bottle_bw per second no matter if
 420                  * other points have 1/2 the RTT and you could get more
 421                  * out...
 422                  */
 423                 bw_avail = *bottle_bw;
 424         }
 425         if (*on_queue > bw_avail) {
 426                 /*
 427                  * No room for anything else don't allow anything else to be
 428                  * "added to the fire".
 429                  */
 430                 int seg_inflight, seg_onqueue, my_portion;
 431
 432                 net->partial_bytes_acked = 0;
 433
 434                 /* how much are we over queue size? */
 435                 incr = *on_queue - bw_avail;
 436                 if (stcb->asoc.seen_a_sack_this_pkt) {
 437                         /*
 438                          * undo any cwnd adjustment that the sack might have
 439                          * made
 440                          */
 441                         net->cwnd = net->prev_cwnd;
 442                 }
 443                 /* Now how much of that is mine? */
 444                 seg_inflight = net->flight_size / net->mtu;
 445                 seg_onqueue = *on_queue / net->mtu;
 446                 my_portion = (incr * seg_inflight) / seg_onqueue;
 447
 448                 /* Have I made an adjustment already */
 449                 if (net->cwnd > net->flight_size) {
 450                         /*
 451                          * for this flight I made an adjustment we need to
 452                          * decrease the portion by a share our previous
 453                          * adjustment.
 454                          */
 455                         int diff_adj;
 456
 457                         diff_adj = net->cwnd - net->flight_size;
 458                         if (diff_adj > my_portion)
 459                                 my_portion = 0;
 460                         else
 461                                 my_portion -= diff_adj;
 462                 }
 463                 /*
 464                  * back down to the previous cwnd (assume we have had a sack
 465                  * before this packet). minus what ever portion of the
 466                  * overage is my fault.
 467                  */
 468                 net->cwnd -= my_portion;
 469
 470                 /* we will NOT back down more than 1 MTU */
 471                 if (net->cwnd <= net->mtu) {
 472                         net->cwnd = net->mtu;
 473                 }
 474                 /* force into CA */
 475                 net->ssthresh = net->cwnd - 1;
 476         } else {
 477                 /*
 478                  * Take 1/4 of the space left or max burst up .. whichever
 479                  * is less.
 480                  */
 481                 incr = min((bw_avail - *on_queue) >> 2,
 482                     stcb->asoc.max_burst * net->mtu);
 483                 net->cwnd += incr;
 484         }
 485         if (net->cwnd > bw_avail) {
 486                 /* We can't exceed the pipe size */
 487                 net->cwnd = bw_avail;
 488         }
 489         if (net->cwnd < net->mtu) {
 490                 /* We always have 1 MTU */
 491                 net->cwnd = net->mtu;
 492         }
 493         if (net->cwnd - old_cwnd != 0) {
 494                 /* log only changes */
 495                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 496                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
 497                             SCTP_CWND_LOG_FROM_SAT);
 498                 }
 499         }
 500 }
 501
 502 void
 503 sctp_cwnd_update_after_output(struct sctp_tcb *stcb,
 504     struct sctp_nets *net, int burst_limit)
 505 {
 506         int old_cwnd = net->cwnd;
 507
 508         if (net->ssthresh < net->cwnd)
 509                 net->ssthresh = net->cwnd;
 510         net->cwnd = (net->flight_size + (burst_limit * net->mtu));
 511
 512         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 513                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_BRST);
 514         }
 515 }
 516
 517 void
 518 sctp_cwnd_update_after_fr_timer(struct sctp_inpcb *inp,
 519     struct sctp_tcb *stcb, struct sctp_nets *net)
 520 {
 521         int old_cwnd = net->cwnd;
 522
 523         sctp_chunk_output(inp, stcb, SCTP_OUTPUT_FROM_EARLY_FR_TMR, SCTP_SO_NOT_LOCKED);
 524         /*
 525          * make a small adjustment to cwnd and force to CA.
 526          */
 527         if (net->cwnd > net->mtu)
 528                 /* drop down one MTU after sending */
 529                 net->cwnd -= net->mtu;
 530         if (net->cwnd < net->ssthresh)
 531                 /* still in SS move to CA */
 532                 net->ssthresh = net->cwnd - 1;
 533         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 534                 sctp_log_cwnd(stcb, net, (old_cwnd - net->cwnd), SCTP_CWND_LOG_FROM_FR);
 535         }
 536 }
 537
 538 struct sctp_hs_raise_drop {
 539         int32_t cwnd;
 540         int32_t increase;
 541         int32_t drop_percent;
 542 };
 543
 544 #define SCTP_HS_TABLE_SIZE 73
 545
 546 struct sctp_hs_raise_drop sctp_cwnd_adjust[SCTP_HS_TABLE_SIZE] = {
 547         {38, 1, 50},            /* 0   */
 548         {118, 2, 44},           /* 1   */
 549         {221, 3, 41},           /* 2   */
 550         {347, 4, 38},           /* 3   */
 551         {495, 5, 37},           /* 4   */
 552         {663, 6, 35},           /* 5   */
 553         {851, 7, 34},           /* 6   */
 554         {1058, 8, 33},          /* 7   */
 555         {1284, 9, 32},          /* 8   */
 556         {1529, 10, 31},         /* 9   */
 557         {1793, 11, 30},         /* 10  */
 558         {2076, 12, 29},         /* 11  */
 559         {2378, 13, 28},         /* 12  */
 560         {2699, 14, 28},         /* 13  */
 561         {3039, 15, 27},         /* 14  */
 562         {3399, 16, 27},         /* 15  */
 563         {3778, 17, 26},         /* 16  */
 564         {4177, 18, 26},         /* 17  */
 565         {4596, 19, 25},         /* 18  */
 566         {5036, 20, 25},         /* 19  */
 567         {5497, 21, 24},         /* 20  */
 568         {5979, 22, 24},         /* 21  */
 569         {6483, 23, 23},         /* 22  */
 570         {7009, 24, 23},         /* 23  */
 571         {7558, 25, 22},         /* 24  */
 572         {8130, 26, 22},         /* 25  */
 573         {8726, 27, 22},         /* 26  */
 574         {9346, 28, 21},         /* 27  */
 575         {9991, 29, 21},         /* 28  */
 576         {10661, 30, 21},        /* 29  */
 577         {11358, 31, 20},        /* 30  */
 578         {12082, 32, 20},        /* 31  */
 579         {12834, 33, 20},        /* 32  */
 580         {13614, 34, 19},        /* 33  */
 581         {14424, 35, 19},        /* 34  */
 582         {15265, 36, 19},        /* 35  */
 583         {16137, 37, 19},        /* 36  */
 584         {17042, 38, 18},        /* 37  */
 585         {17981, 39, 18},        /* 38  */
 586         {18955, 40, 18},        /* 39  */
 587         {19965, 41, 17},        /* 40  */
 588         {21013, 42, 17},        /* 41  */
 589         {22101, 43, 17},        /* 42  */
 590         {23230, 44, 17},        /* 43  */
 591         {24402, 45, 16},        /* 44  */
 592         {25618, 46, 16},        /* 45  */
 593         {26881, 47, 16},        /* 46  */
 594         {28193, 48, 16},        /* 47  */
 595         {29557, 49, 15},        /* 48  */
 596         {30975, 50, 15},        /* 49  */
 597         {32450, 51, 15},        /* 50  */
 598         {33986, 52, 15},        /* 51  */
 599         {35586, 53, 14},        /* 52  */
 600         {37253, 54, 14},        /* 53  */
 601         {38992, 55, 14},        /* 54  */
 602         {40808, 56, 14},        /* 55  */
 603         {42707, 57, 13},        /* 56  */
 604         {44694, 58, 13},        /* 57  */
 605         {46776, 59, 13},        /* 58  */
 606         {48961, 60, 13},        /* 59  */
 607         {51258, 61, 13},        /* 60  */
 608         {53677, 62, 12},        /* 61  */
 609         {56230, 63, 12},        /* 62  */
 610         {58932, 64, 12},        /* 63  */
 611         {61799, 65, 12},        /* 64  */
 612         {64851, 66, 11},        /* 65  */
 613         {68113, 67, 11},        /* 66  */
 614         {71617, 68, 11},        /* 67  */
 615         {75401, 69, 10},        /* 68  */
 616         {79517, 70, 10},        /* 69  */
 617         {84035, 71, 10},        /* 70  */
 618         {89053, 72, 10},        /* 71  */
 619         {94717, 73, 9}          /* 72  */
 620 };
 621
 622 static void
 623 sctp_hs_cwnd_increase(struct sctp_tcb *stcb, struct sctp_nets *net)
 624 {
 625         int cur_val, i, indx, incr;
 626
 627         cur_val = net->cwnd >> 10;
 628         indx = SCTP_HS_TABLE_SIZE - 1;
 629 #ifdef SCTP_DEBUG
 630         printf("HS CC CAlled.\n");
 631 #endif
 632         if (cur_val < sctp_cwnd_adjust[0].cwnd) {
 633                 /* normal mode */
 634                 if (net->net_ack > net->mtu) {
 635                         net->cwnd += net->mtu;
 636                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 637                                 sctp_log_cwnd(stcb, net, net->mtu, SCTP_CWND_LOG_FROM_SS);
 638                         }
 639                 } else {
 640                         net->cwnd += net->net_ack;
 641                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 642                                 sctp_log_cwnd(stcb, net, net->net_ack, SCTP_CWND_LOG_FROM_SS);
 643                         }
 644                 }
 645         } else {
 646                 for (i = net->last_hs_used; i < SCTP_HS_TABLE_SIZE; i++) {
 647                         if (cur_val < sctp_cwnd_adjust[i].cwnd) {
 648                                 indx = i;
 649                                 break;
 650                         }
 651                 }
 652                 net->last_hs_used = indx;
 653                 incr = ((sctp_cwnd_adjust[indx].increase) << 10);
 654                 net->cwnd += incr;
 655                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 656                         sctp_log_cwnd(stcb, net, incr, SCTP_CWND_LOG_FROM_SS);
 657                 }
 658         }
 659 }
 660
 661 static void
 662 sctp_hs_cwnd_decrease(struct sctp_tcb *stcb, struct sctp_nets *net)
 663 {
 664         int cur_val, i, indx;
 665         int old_cwnd = net->cwnd;
 666
 667         cur_val = net->cwnd >> 10;
 668         if (cur_val < sctp_cwnd_adjust[0].cwnd) {
 669                 /* normal mode */
 670                 net->ssthresh = net->cwnd / 2;
 671                 if (net->ssthresh < (net->mtu * 2)) {
 672                         net->ssthresh = 2 * net->mtu;
 673                 }
 674                 net->cwnd = net->ssthresh;
 675         } else {
 676                 /* drop by the proper amount */
 677                 net->ssthresh = net->cwnd - (int)((net->cwnd / 100) *
 678                     sctp_cwnd_adjust[net->last_hs_used].drop_percent);
 679                 net->cwnd = net->ssthresh;
 680                 /* now where are we */
 681                 indx = net->last_hs_used;
 682                 cur_val = net->cwnd >> 10;
 683                 /* reset where we are in the table */
 684                 if (cur_val < sctp_cwnd_adjust[0].cwnd) {
 685                         /* feel out of hs */
 686                         net->last_hs_used = 0;
 687                 } else {
 688                         for (i = indx; i >= 1; i--) {
 689                                 if (cur_val > sctp_cwnd_adjust[i - 1].cwnd) {
 690                                         break;
 691                                 }
 692                         }
 693                         net->last_hs_used = indx;
 694                 }
 695         }
 696         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 697                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_FR);
 698         }
 699 }
 700
 701 void
 702 sctp_hs_cwnd_update_after_fr(struct sctp_tcb *stcb,
 703     struct sctp_association *asoc)
 704 {
 705         struct sctp_nets *net;
 706
 707         /*
 708          * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off == 1) &&
 709          * (net->fast_retran_loss_recovery == 0)))
 710          */
 711         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
 712                 if ((asoc->fast_retran_loss_recovery == 0) ||
 713                     (asoc->sctp_cmt_on_off == 1)) {
 714                         /* out of a RFC2582 Fast recovery window? */
 715                         if (net->net_ack > 0) {
 716                                 /*
 717                                  * per section 7.2.3, are there any
 718                                  * destinations that had a fast retransmit
 719                                  * to them. If so what we need to do is
 720                                  * adjust ssthresh and cwnd.
 721                                  */
 722                                 struct sctp_tmit_chunk *lchk;
 723
 724                                 sctp_hs_cwnd_decrease(stcb, net);
 725
 726                                 lchk = TAILQ_FIRST(&asoc->send_queue);
 727
 728                                 net->partial_bytes_acked = 0;
 729                                 /* Turn on fast recovery window */
 730                                 asoc->fast_retran_loss_recovery = 1;
 731                                 if (lchk == NULL) {
 732                                         /* Mark end of the window */
 733                                         asoc->fast_recovery_tsn = asoc->sending_seq - 1;
 734                                 } else {
 735                                         asoc->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
 736                                 }
 737
 738                                 /*
 739                                  * CMT fast recovery -- per destination
 740                                  * recovery variable.
 741                                  */
 742                                 net->fast_retran_loss_recovery = 1;
 743
 744                                 if (lchk == NULL) {
 745                                         /* Mark end of the window */
 746                                         net->fast_recovery_tsn = asoc->sending_seq - 1;
 747                                 } else {
 748                                         net->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
 749                                 }
 750
 751                                 /*
 752                                  * Disable Nonce Sum Checking and store the
 753                                  * resync tsn
 754                                  */
 755                                 asoc->nonce_sum_check = 0;
 756                                 asoc->nonce_resync_tsn = asoc->fast_recovery_tsn + 1;
 757
 758                                 sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
 759                                     stcb->sctp_ep, stcb, net, SCTP_FROM_SCTP_INDATA + SCTP_LOC_32);
 760                                 sctp_timer_start(SCTP_TIMER_TYPE_SEND,
 761                                     stcb->sctp_ep, stcb, net);
 762                         }
 763                 } else if (net->net_ack > 0) {
 764                         /*
 765                          * Mark a peg that we WOULD have done a cwnd
 766                          * reduction but RFC2582 prevented this action.
 767                          */
 768                         SCTP_STAT_INCR(sctps_fastretransinrtt);
 769                 }
 770         }
 771 }
 772
 773 void
 774 sctp_hs_cwnd_update_after_sack(struct sctp_tcb *stcb,
 775     struct sctp_association *asoc,
 776     int accum_moved, int reneged_all, int will_exit)
 777 {
 778         struct sctp_nets *net;
 779
 780         /******************************/
 781         /* update cwnd and Early FR   */
 782         /******************************/
 783         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
 784
 785 #ifdef JANA_CMT_FAST_RECOVERY
 786                 /*
 787                  * CMT fast recovery code. Need to debug.
 788                  */
 789                 if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
 790                         if (compare_with_wrap(asoc->last_acked_seq,
 791                             net->fast_recovery_tsn, MAX_TSN) ||
 792                             (asoc->last_acked_seq == net->fast_recovery_tsn) ||
 793                             compare_with_wrap(net->pseudo_cumack, net->fast_recovery_tsn, MAX_TSN) ||
 794                             (net->pseudo_cumack == net->fast_recovery_tsn)) {
 795                                 net->will_exit_fast_recovery = 1;
 796                         }
 797                 }
 798 #endif
 799                 if (SCTP_BASE_SYSCTL(sctp_early_fr)) {
 800                         /*
 801                          * So, first of all do we need to have a Early FR
 802                          * timer running?
 803                          */
 804                         if ((!TAILQ_EMPTY(&asoc->sent_queue) &&
 805                             (net->ref_count > 1) &&
 806                             (net->flight_size < net->cwnd)) ||
 807                             (reneged_all)) {
 808                                 /*
 809                                  * yes, so in this case stop it if its
 810                                  * running, and then restart it. Reneging
 811                                  * all is a special case where we want to
 812                                  * run the Early FR timer and then force the
 813                                  * last few unacked to be sent, causing us
 814                                  * to illicit a sack with gaps to force out
 815                                  * the others.
 816                                  */
 817                                 if (SCTP_OS_TIMER_PENDING(&net->fr_timer.timer)) {
 818                                         SCTP_STAT_INCR(sctps_earlyfrstpidsck2);
 819                                         sctp_timer_stop(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net,
 820                                             SCTP_FROM_SCTP_INDATA + SCTP_LOC_20);
 821                                 }
 822                                 SCTP_STAT_INCR(sctps_earlyfrstrid);
 823                                 sctp_timer_start(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net);
 824                         } else {
 825                                 /* No, stop it if its running */
 826                                 if (SCTP_OS_TIMER_PENDING(&net->fr_timer.timer)) {
 827                                         SCTP_STAT_INCR(sctps_earlyfrstpidsck3);
 828                                         sctp_timer_stop(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net,
 829                                             SCTP_FROM_SCTP_INDATA + SCTP_LOC_21);
 830                                 }
 831                         }
 832                 }
 833                 /* if nothing was acked on this destination skip it */
 834                 if (net->net_ack == 0) {
 835                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 836                                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
 837                         }
 838                         continue;
 839                 }
 840                 if (net->net_ack2 > 0) {
 841                         /*
 842                          * Karn's rule applies to clearing error count, this
 843                          * is optional.
 844                          */
 845                         net->error_count = 0;
 846                         if ((net->dest_state & SCTP_ADDR_NOT_REACHABLE) ==
 847                             SCTP_ADDR_NOT_REACHABLE) {
 848                                 /* addr came good */
 849                                 net->dest_state &= ~SCTP_ADDR_NOT_REACHABLE;
 850                                 net->dest_state |= SCTP_ADDR_REACHABLE;
 851                                 sctp_ulp_notify(SCTP_NOTIFY_INTERFACE_UP, stcb,
 852                                     SCTP_RECEIVED_SACK, (void *)net, SCTP_SO_NOT_LOCKED);
 853                                 /* now was it the primary? if so restore */
 854                                 if (net->dest_state & SCTP_ADDR_WAS_PRIMARY) {
 855                                         (void)sctp_set_primary_addr(stcb, (struct sockaddr *)NULL, net);
 856                                 }
 857                         }
 858                         /*
 859                          * JRS 5/14/07 - If CMT PF is on and the destination
 860                          * is in PF state, set the destination to active
 861                          * state and set the cwnd to one or two MTU's based
 862                          * on whether PF1 or PF2 is being used.
 863                          *
 864                          * Should we stop any running T3 timer here?
 865                          */
 866                         if ((asoc->sctp_cmt_on_off == 1) &&
 867                             (asoc->sctp_cmt_pf > 0) &&
 868                             ((net->dest_state & SCTP_ADDR_PF) == SCTP_ADDR_PF)) {
 869                                 net->dest_state &= ~SCTP_ADDR_PF;
 870                                 net->cwnd = net->mtu * asoc->sctp_cmt_pf;
 871                                 SCTPDBG(SCTP_DEBUG_INDATA1, "Destination %p moved from PF to reachable with cwnd %d.\n",
 872                                     net, net->cwnd);
 873                                 /*
 874                                  * Since the cwnd value is explicitly set,
 875                                  * skip the code that updates the cwnd
 876                                  * value.
 877                                  */
 878                                 goto skip_cwnd_update;
 879                         }
 880                 }
 881 #ifdef JANA_CMT_FAST_RECOVERY
 882                 /*
 883                  * CMT fast recovery code
 884                  */
 885                 /*
 886                  * if (sctp_cmt_on_off == 1 &&
 887                  * net->fast_retran_loss_recovery &&
 888                  * net->will_exit_fast_recovery == 0) { @@@ Do something }
 889                  * else if (sctp_cmt_on_off == 0 &&
 890                  * asoc->fast_retran_loss_recovery && will_exit == 0) {
 891                  */
 892 #endif
 893
 894                 if (asoc->fast_retran_loss_recovery &&
 895                     (will_exit == 0) &&
 896                     (asoc->sctp_cmt_on_off == 0)) {
 897                         /*
 898                          * If we are in loss recovery we skip any cwnd
 899                          * update
 900                          */
 901                         goto skip_cwnd_update;
 902                 }
 903                 /*
 904                  * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
 905                  * moved.
 906                  */
 907                 if (accum_moved ||
 908                     ((asoc->sctp_cmt_on_off == 1) && net->new_pseudo_cumack)) {
 909                         /* If the cumulative ack moved we can proceed */
 910                         if (net->cwnd <= net->ssthresh) {
 911                                 /* We are in slow start */
 912                                 if (net->flight_size + net->net_ack >= net->cwnd) {
 913
 914                                         sctp_hs_cwnd_increase(stcb, net);
 915
 916                                 } else {
 917                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 918                                                 sctp_log_cwnd(stcb, net, net->net_ack,
 919                                                     SCTP_CWND_LOG_NOADV_SS);
 920                                         }
 921                                 }
 922                         } else {
 923                                 /* We are in congestion avoidance */
 924                                 net->partial_bytes_acked += net->net_ack;
 925                                 if ((net->flight_size + net->net_ack >= net->cwnd) &&
 926                                     (net->partial_bytes_acked >= net->cwnd)) {
 927                                         net->partial_bytes_acked -= net->cwnd;
 928                                         net->cwnd += net->mtu;
 929                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 930                                                 sctp_log_cwnd(stcb, net, net->mtu,
 931                                                     SCTP_CWND_LOG_FROM_CA);
 932                                         }
 933                                 } else {
 934                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 935                                                 sctp_log_cwnd(stcb, net, net->net_ack,
 936                                                     SCTP_CWND_LOG_NOADV_CA);
 937                                         }
 938                                 }
 939                         }
 940                 } else {
 941                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 942                                 sctp_log_cwnd(stcb, net, net->mtu,
 943                                     SCTP_CWND_LOG_NO_CUMACK);
 944                         }
 945                 }
 946 skip_cwnd_update:
 947                 /*
 948                  * NOW, according to Karn's rule do we need to restore the
 949                  * RTO timer back? Check our net_ack2. If not set then we
 950                  * have a ambiguity.. i.e. all data ack'd was sent to more
 951                  * than one place.
 952                  */
 953                 if (net->net_ack2) {
 954                         /* restore any doubled timers */
 955                         net->RTO = ((net->lastsa >> 2) + net->lastsv) >> 1;
 956                         if (net->RTO < stcb->asoc.minrto) {
 957                                 net->RTO = stcb->asoc.minrto;
 958                         }
 959                         if (net->RTO > stcb->asoc.maxrto) {
 960                                 net->RTO = stcb->asoc.maxrto;
 961                         }
 962                 }
 963         }
 964 }
 965
 966
 967 /*
 968  * H-TCP congestion control. The algorithm is detailed in:
 969  * R.N.Shorten, D.J.Leith:
 970  *   "H-TCP: TCP for high-speed and long-distance networks"
 971  *   Proc. PFLDnet, Argonne, 2004.
 972  * http://www.hamilton.ie/net/htcp3.pdf
 973  */
 974
 975
 976 static int use_rtt_scaling = 1;
 977 static int use_bandwidth_switch = 1;
 978
 979 static inline int
 980 between(uint32_t seq1, uint32_t seq2, uint32_t seq3)
 981 {
 982         return seq3 - seq2 >= seq1 - seq2;
 983 }
 984
 985 static inline uint32_t
 986 htcp_cong_time(struct htcp *ca)
 987 {
 988         return sctp_get_tick_count() - ca->last_cong;
 989 }
 990
 991 static inline uint32_t
 992 htcp_ccount(struct htcp *ca)
 993 {
 994         return htcp_cong_time(ca) / ca->minRTT;
 995 }
 996
 997 static inline void
 998 htcp_reset(struct htcp *ca)
 999 {
1000         ca->undo_last_cong = ca->last_cong;
1001         ca->undo_maxRTT = ca->maxRTT;
1002         ca->undo_old_maxB = ca->old_maxB;
1003         ca->last_cong = sctp_get_tick_count();
1004 }
1005
1006 #ifdef SCTP_NOT_USED
1007
1008 static uint32_t
1009 htcp_cwnd_undo(struct sctp_tcb *stcb, struct sctp_nets *net)
1010 {
1011         net->htcp_ca.last_cong = net->htcp_ca.undo_last_cong;
1012         net->htcp_ca.maxRTT = net->htcp_ca.undo_maxRTT;
1013         net->htcp_ca.old_maxB = net->htcp_ca.undo_old_maxB;
1014         return max(net->cwnd, ((net->ssthresh / net->mtu << 7) / net->htcp_ca.beta) * net->mtu);
1015 }
1016
1017 #endif
1018
1019 static inline void
1020 measure_rtt(struct sctp_tcb *stcb, struct sctp_nets *net)
1021 {
1022         uint32_t srtt = net->lastsa >> 3;
1023
1024         /* keep track of minimum RTT seen so far, minRTT is zero at first */
1025         if (net->htcp_ca.minRTT > srtt || !net->htcp_ca.minRTT)
1026                 net->htcp_ca.minRTT = srtt;
1027
1028         /* max RTT */
1029         if (net->fast_retran_ip == 0 && net->ssthresh < 0xFFFF && htcp_ccount(&net->htcp_ca) > 3) {
1030                 if (net->htcp_ca.maxRTT < net->htcp_ca.minRTT)
1031                         net->htcp_ca.maxRTT = net->htcp_ca.minRTT;
1032                 if (net->htcp_ca.maxRTT < srtt && srtt <= net->htcp_ca.maxRTT + MSEC_TO_TICKS(20))
1033                         net->htcp_ca.maxRTT = srtt;
1034         }
1035 }
1036
1037 static void
1038 measure_achieved_throughput(struct sctp_tcb *stcb, struct sctp_nets *net)
1039 {
1040         uint32_t now = sctp_get_tick_count();
1041
1042         if (net->fast_retran_ip == 0)
1043                 net->htcp_ca.bytes_acked = net->net_ack;
1044
1045         if (!use_bandwidth_switch)
1046                 return;
1047
1048         /* achieved throughput calculations */
1049         /* JRS - not 100% sure of this statement */
1050         if (net->fast_retran_ip == 1) {
1051                 net->htcp_ca.bytecount = 0;
1052                 net->htcp_ca.lasttime = now;
1053                 return;
1054         }
1055         net->htcp_ca.bytecount += net->net_ack;
1056
1057         if (net->htcp_ca.bytecount >= net->cwnd - ((net->htcp_ca.alpha >> 7 ? : 1) * net->mtu)
1058             && now - net->htcp_ca.lasttime >= net->htcp_ca.minRTT
1059             && net->htcp_ca.minRTT > 0) {
1060                 uint32_t cur_Bi = net->htcp_ca.bytecount / net->mtu * hz / (now - net->htcp_ca.lasttime);
1061
1062                 if (htcp_ccount(&net->htcp_ca) <= 3) {
1063                         /* just after backoff */
1064                         net->htcp_ca.minB = net->htcp_ca.maxB = net->htcp_ca.Bi = cur_Bi;
1065                 } else {
1066                         net->htcp_ca.Bi = (3 * net->htcp_ca.Bi + cur_Bi) / 4;
1067                         if (net->htcp_ca.Bi > net->htcp_ca.maxB)
1068                                 net->htcp_ca.maxB = net->htcp_ca.Bi;
1069                         if (net->htcp_ca.minB > net->htcp_ca.maxB)
1070                                 net->htcp_ca.minB = net->htcp_ca.maxB;
1071                 }
1072                 net->htcp_ca.bytecount = 0;
1073                 net->htcp_ca.lasttime = now;
1074         }
1075 }
1076
1077 static inline void
1078 htcp_beta_update(struct htcp *ca, uint32_t minRTT, uint32_t maxRTT)
1079 {
1080         if (use_bandwidth_switch) {
1081                 uint32_t maxB = ca->maxB;
1082                 uint32_t old_maxB = ca->old_maxB;
1083
1084                 ca->old_maxB = ca->maxB;
1085
1086                 if (!between(5 * maxB, 4 * old_maxB, 6 * old_maxB)) {
1087                         ca->beta = BETA_MIN;
1088                         ca->modeswitch = 0;
1089                         return;
1090                 }
1091         }
1092         if (ca->modeswitch && minRTT > (uint32_t) MSEC_TO_TICKS(10) && maxRTT) {
1093                 ca->beta = (minRTT << 7) / maxRTT;
1094                 if (ca->beta < BETA_MIN)
1095                         ca->beta = BETA_MIN;
1096                 else if (ca->beta > BETA_MAX)
1097                         ca->beta = BETA_MAX;
1098         } else {
1099                 ca->beta = BETA_MIN;
1100                 ca->modeswitch = 1;
1101         }
1102 }
1103
1104 static inline void
1105 htcp_alpha_update(struct htcp *ca)
1106 {
1107         uint32_t minRTT = ca->minRTT;
1108         uint32_t factor = 1;
1109         uint32_t diff = htcp_cong_time(ca);
1110
1111         if (diff > (uint32_t) hz) {
1112                 diff -= hz;
1113                 factor = 1 + (10 * diff + ((diff / 2) * (diff / 2) / hz)) / hz;
1114         }
1115         if (use_rtt_scaling && minRTT) {
1116                 uint32_t scale = (hz << 3) / (10 * minRTT);
1117
1118                 scale = min(max(scale, 1U << 2), 10U << 3);     /* clamping ratio to
1119                                                                  * interval [0.5,10]<<3 */
1120                 factor = (factor << 3) / scale;
1121                 if (!factor)
1122                         factor = 1;
1123         }
1124         ca->alpha = 2 * factor * ((1 << 7) - ca->beta);
1125         if (!ca->alpha)
1126                 ca->alpha = ALPHA_BASE;
1127 }
1128
1129 /* After we have the rtt data to calculate beta, we'd still prefer to wait one
1130  * rtt before we adjust our beta to ensure we are working from a consistent
1131  * data.
1132  *
1133  * This function should be called when we hit a congestion event since only at
1134  * that point do we really have a real sense of maxRTT (the queues en route
1135  * were getting just too full now).
1136  */
1137 static void
1138 htcp_param_update(struct sctp_tcb *stcb, struct sctp_nets *net)
1139 {
1140         uint32_t minRTT = net->htcp_ca.minRTT;
1141         uint32_t maxRTT = net->htcp_ca.maxRTT;
1142
1143         htcp_beta_update(&net->htcp_ca, minRTT, maxRTT);
1144         htcp_alpha_update(&net->htcp_ca);
1145
1146         /*
1147          * add slowly fading memory for maxRTT to accommodate routing
1148          * changes etc
1149          */
1150         if (minRTT > 0 && maxRTT > minRTT)
1151                 net->htcp_ca.maxRTT = minRTT + ((maxRTT - minRTT) * 95) / 100;
1152 }
1153
1154 static uint32_t
1155 htcp_recalc_ssthresh(struct sctp_tcb *stcb, struct sctp_nets *net)
1156 {
1157         htcp_param_update(stcb, net);
1158         return max(((net->cwnd / net->mtu * net->htcp_ca.beta) >> 7) * net->mtu, 2U * net->mtu);
1159 }
1160
1161 static void
1162 htcp_cong_avoid(struct sctp_tcb *stcb, struct sctp_nets *net)
1163 {
1164         /*-
1165          * How to handle these functions?
1166          *      if (!tcp_is_cwnd_limited(sk, in_flight)) RRS - good question.
1167          *              return;
1168          */
1169         if (net->cwnd <= net->ssthresh) {
1170                 /* We are in slow start */
1171                 if (net->flight_size + net->net_ack >= net->cwnd) {
1172                         if (net->net_ack > (net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable))) {
1173                                 net->cwnd += (net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable));
1174                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1175                                         sctp_log_cwnd(stcb, net, net->mtu,
1176                                             SCTP_CWND_LOG_FROM_SS);
1177                                 }
1178                         } else {
1179                                 net->cwnd += net->net_ack;
1180                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1181                                         sctp_log_cwnd(stcb, net, net->net_ack,
1182                                             SCTP_CWND_LOG_FROM_SS);
1183                                 }
1184                         }
1185                 } else {
1186                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1187                                 sctp_log_cwnd(stcb, net, net->net_ack,
1188                                     SCTP_CWND_LOG_NOADV_SS);
1189                         }
1190                 }
1191         } else {
1192                 measure_rtt(stcb, net);
1193
1194                 /*
1195                  * In dangerous area, increase slowly. In theory this is
1196                  * net->cwnd += alpha / net->cwnd
1197                  */
1198                 /* What is snd_cwnd_cnt?? */
1199                 if (((net->partial_bytes_acked / net->mtu * net->htcp_ca.alpha) >> 7) * net->mtu >= net->cwnd) {
1200                         /*-
1201                          * Does SCTP have a cwnd clamp?
1202                          * if (net->snd_cwnd < net->snd_cwnd_clamp) - Nope (RRS).
1203                          */
1204                         net->cwnd += net->mtu;
1205                         net->partial_bytes_acked = 0;
1206                         htcp_alpha_update(&net->htcp_ca);
1207                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1208                                 sctp_log_cwnd(stcb, net, net->mtu,
1209                                     SCTP_CWND_LOG_FROM_CA);
1210                         }
1211                 } else {
1212                         net->partial_bytes_acked += net->net_ack;
1213                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1214                                 sctp_log_cwnd(stcb, net, net->net_ack,
1215                                     SCTP_CWND_LOG_NOADV_CA);
1216                         }
1217                 }
1218
1219                 net->htcp_ca.bytes_acked = net->mtu;
1220         }
1221 }
1222
1223 #ifdef SCTP_NOT_USED
1224 /* Lower bound on congestion window. */
1225 static uint32_t
1226 htcp_min_cwnd(struct sctp_tcb *stcb, struct sctp_nets *net)
1227 {
1228         return net->ssthresh;
1229 }
1230
1231 #endif
1232
1233 static void
1234 htcp_init(struct sctp_tcb *stcb, struct sctp_nets *net)
1235 {
1236         memset(&net->htcp_ca, 0, sizeof(struct htcp));
1237         net->htcp_ca.alpha = ALPHA_BASE;
1238         net->htcp_ca.beta = BETA_MIN;
1239         net->htcp_ca.bytes_acked = net->mtu;
1240         net->htcp_ca.last_cong = sctp_get_tick_count();
1241 }
1242
1243 void
1244 sctp_htcp_set_initial_cc_param(struct sctp_tcb *stcb, struct sctp_nets *net)
1245 {
1246         /*
1247          * We take the max of the burst limit times a MTU or the
1248          * INITIAL_CWND. We then limit this to 4 MTU's of sending.
1249          */
1250         net->cwnd = min((net->mtu * 4), max((2 * net->mtu), SCTP_INITIAL_CWND));
1251         net->ssthresh = stcb->asoc.peers_rwnd;
1252         htcp_init(stcb, net);
1253
1254         if (SCTP_BASE_SYSCTL(sctp_logging_level) & (SCTP_CWND_MONITOR_ENABLE | SCTP_CWND_LOGGING_ENABLE)) {
1255                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_INITIALIZATION);
1256         }
1257 }
1258
1259 void
1260 sctp_htcp_cwnd_update_after_sack(struct sctp_tcb *stcb,
1261     struct sctp_association *asoc,
1262     int accum_moved, int reneged_all, int will_exit)
1263 {
1264         struct sctp_nets *net;
1265
1266         /******************************/
1267         /* update cwnd and Early FR   */
1268         /******************************/
1269         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
1270
1271 #ifdef JANA_CMT_FAST_RECOVERY
1272                 /*
1273                  * CMT fast recovery code. Need to debug.
1274                  */
1275                 if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
1276                         if (compare_with_wrap(asoc->last_acked_seq,
1277                             net->fast_recovery_tsn, MAX_TSN) ||
1278                             (asoc->last_acked_seq == net->fast_recovery_tsn) ||
1279                             compare_with_wrap(net->pseudo_cumack, net->fast_recovery_tsn, MAX_TSN) ||
1280                             (net->pseudo_cumack == net->fast_recovery_tsn)) {
1281                                 net->will_exit_fast_recovery = 1;
1282                         }
1283                 }
1284 #endif
1285                 if (SCTP_BASE_SYSCTL(sctp_early_fr)) {
1286                         /*
1287                          * So, first of all do we need to have a Early FR
1288                          * timer running?
1289                          */
1290                         if ((!TAILQ_EMPTY(&asoc->sent_queue) &&
1291                             (net->ref_count > 1) &&
1292                             (net->flight_size < net->cwnd)) ||
1293                             (reneged_all)) {
1294                                 /*
1295                                  * yes, so in this case stop it if its
1296                                  * running, and then restart it. Reneging
1297                                  * all is a special case where we want to
1298                                  * run the Early FR timer and then force the
1299                                  * last few unacked to be sent, causing us
1300                                  * to illicit a sack with gaps to force out
1301                                  * the others.
1302                                  */
1303                                 if (SCTP_OS_TIMER_PENDING(&net->fr_timer.timer)) {
1304                                         SCTP_STAT_INCR(sctps_earlyfrstpidsck2);
1305                                         sctp_timer_stop(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net,
1306                                             SCTP_FROM_SCTP_INDATA + SCTP_LOC_20);
1307                                 }
1308                                 SCTP_STAT_INCR(sctps_earlyfrstrid);
1309                                 sctp_timer_start(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net);
1310                         } else {
1311                                 /* No, stop it if its running */
1312                                 if (SCTP_OS_TIMER_PENDING(&net->fr_timer.timer)) {
1313                                         SCTP_STAT_INCR(sctps_earlyfrstpidsck3);
1314                                         sctp_timer_stop(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net,
1315                                             SCTP_FROM_SCTP_INDATA + SCTP_LOC_21);
1316                                 }
1317                         }
1318                 }
1319                 /* if nothing was acked on this destination skip it */
1320                 if (net->net_ack == 0) {
1321                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1322                                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
1323                         }
1324                         continue;
1325                 }
1326                 if (net->net_ack2 > 0) {
1327                         /*
1328                          * Karn's rule applies to clearing error count, this
1329                          * is optional.
1330                          */
1331                         net->error_count = 0;
1332                         if ((net->dest_state & SCTP_ADDR_NOT_REACHABLE) ==
1333                             SCTP_ADDR_NOT_REACHABLE) {
1334                                 /* addr came good */
1335                                 net->dest_state &= ~SCTP_ADDR_NOT_REACHABLE;
1336                                 net->dest_state |= SCTP_ADDR_REACHABLE;
1337                                 sctp_ulp_notify(SCTP_NOTIFY_INTERFACE_UP, stcb,
1338                                     SCTP_RECEIVED_SACK, (void *)net, SCTP_SO_NOT_LOCKED);
1339                                 /* now was it the primary? if so restore */
1340                                 if (net->dest_state & SCTP_ADDR_WAS_PRIMARY) {
1341                                         (void)sctp_set_primary_addr(stcb, (struct sockaddr *)NULL, net);
1342                                 }
1343                         }
1344                         /*
1345                          * JRS 5/14/07 - If CMT PF is on and the destination
1346                          * is in PF state, set the destination to active
1347                          * state and set the cwnd to one or two MTU's based
1348                          * on whether PF1 or PF2 is being used.
1349                          *
1350                          * Should we stop any running T3 timer here?
1351                          */
1352                         if ((asoc->sctp_cmt_on_off == 1) &&
1353                             (asoc->sctp_cmt_pf > 0) &&
1354                             ((net->dest_state & SCTP_ADDR_PF) == SCTP_ADDR_PF)) {
1355                                 net->dest_state &= ~SCTP_ADDR_PF;
1356                                 net->cwnd = net->mtu * asoc->sctp_cmt_pf;
1357                                 SCTPDBG(SCTP_DEBUG_INDATA1, "Destination %p moved from PF to reachable with cwnd %d.\n",
1358                                     net, net->cwnd);
1359                                 /*
1360                                  * Since the cwnd value is explicitly set,
1361                                  * skip the code that updates the cwnd
1362                                  * value.
1363                                  */
1364                                 goto skip_cwnd_update;
1365                         }
1366                 }
1367 #ifdef JANA_CMT_FAST_RECOVERY
1368                 /*
1369                  * CMT fast recovery code
1370                  */
1371                 /*
1372                  * if (sctp_cmt_on_off == 1 &&
1373                  * net->fast_retran_loss_recovery &&
1374                  * net->will_exit_fast_recovery == 0) { @@@ Do something }
1375                  * else if (sctp_cmt_on_off == 0 &&
1376                  * asoc->fast_retran_loss_recovery && will_exit == 0) {
1377                  */
1378 #endif
1379
1380                 if (asoc->fast_retran_loss_recovery &&
1381                     will_exit == 0 &&
1382                     (asoc->sctp_cmt_on_off == 0)) {
1383                         /*
1384                          * If we are in loss recovery we skip any cwnd
1385                          * update
1386                          */
1387                         goto skip_cwnd_update;
1388                 }
1389                 /*
1390                  * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
1391                  * moved.
1392                  */
1393                 if (accum_moved ||
1394                     ((asoc->sctp_cmt_on_off == 1) && net->new_pseudo_cumack)) {
1395                         htcp_cong_avoid(stcb, net);
1396                         measure_achieved_throughput(stcb, net);
1397                 } else {
1398                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1399                                 sctp_log_cwnd(stcb, net, net->mtu,
1400                                     SCTP_CWND_LOG_NO_CUMACK);
1401                         }
1402                 }
1403 skip_cwnd_update:
1404                 /*
1405                  * NOW, according to Karn's rule do we need to restore the
1406                  * RTO timer back? Check our net_ack2. If not set then we
1407                  * have a ambiguity.. i.e. all data ack'd was sent to more
1408                  * than one place.
1409                  */
1410                 if (net->net_ack2) {
1411                         /* restore any doubled timers */
1412                         net->RTO = ((net->lastsa >> 2) + net->lastsv) >> 1;
1413                         if (net->RTO < stcb->asoc.minrto) {
1414                                 net->RTO = stcb->asoc.minrto;
1415                         }
1416                         if (net->RTO > stcb->asoc.maxrto) {
1417                                 net->RTO = stcb->asoc.maxrto;
1418                         }
1419                 }
1420         }
1421 }
1422
1423 void
1424 sctp_htcp_cwnd_update_after_fr(struct sctp_tcb *stcb,
1425     struct sctp_association *asoc)
1426 {
1427         struct sctp_nets *net;
1428
1429         /*
1430          * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off == 1) &&
1431          * (net->fast_retran_loss_recovery == 0)))
1432          */
1433         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
1434                 if ((asoc->fast_retran_loss_recovery == 0) ||
1435                     (asoc->sctp_cmt_on_off == 1)) {
1436                         /* out of a RFC2582 Fast recovery window? */
1437                         if (net->net_ack > 0) {
1438                                 /*
1439                                  * per section 7.2.3, are there any
1440                                  * destinations that had a fast retransmit
1441                                  * to them. If so what we need to do is
1442                                  * adjust ssthresh and cwnd.
1443                                  */
1444                                 struct sctp_tmit_chunk *lchk;
1445                                 int old_cwnd = net->cwnd;
1446
1447                                 /* JRS - reset as if state were changed */
1448                                 htcp_reset(&net->htcp_ca);
1449                                 net->ssthresh = htcp_recalc_ssthresh(stcb, net);
1450                                 net->cwnd = net->ssthresh;
1451                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1452                                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
1453                                             SCTP_CWND_LOG_FROM_FR);
1454                                 }
1455                                 lchk = TAILQ_FIRST(&asoc->send_queue);
1456
1457                                 net->partial_bytes_acked = 0;
1458                                 /* Turn on fast recovery window */
1459                                 asoc->fast_retran_loss_recovery = 1;
1460                                 if (lchk == NULL) {
1461                                         /* Mark end of the window */
1462                                         asoc->fast_recovery_tsn = asoc->sending_seq - 1;
1463                                 } else {
1464                                         asoc->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
1465                                 }
1466
1467                                 /*
1468                                  * CMT fast recovery -- per destination
1469                                  * recovery variable.
1470                                  */
1471                                 net->fast_retran_loss_recovery = 1;
1472
1473                                 if (lchk == NULL) {
1474                                         /* Mark end of the window */
1475                                         net->fast_recovery_tsn = asoc->sending_seq - 1;
1476                                 } else {
1477                                         net->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
1478                                 }
1479
1480                                 /*
1481                                  * Disable Nonce Sum Checking and store the
1482                                  * resync tsn
1483                                  */
1484                                 asoc->nonce_sum_check = 0;
1485                                 asoc->nonce_resync_tsn = asoc->fast_recovery_tsn + 1;
1486
1487                                 sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
1488                                     stcb->sctp_ep, stcb, net, SCTP_FROM_SCTP_INDATA + SCTP_LOC_32);
1489                                 sctp_timer_start(SCTP_TIMER_TYPE_SEND,
1490                                     stcb->sctp_ep, stcb, net);
1491                         }
1492                 } else if (net->net_ack > 0) {
1493                         /*
1494                          * Mark a peg that we WOULD have done a cwnd
1495                          * reduction but RFC2582 prevented this action.
1496                          */
1497                         SCTP_STAT_INCR(sctps_fastretransinrtt);
1498                 }
1499         }
1500 }
1501
1502 void
1503 sctp_htcp_cwnd_update_after_timeout(struct sctp_tcb *stcb,
1504     struct sctp_nets *net)
1505 {
1506         int old_cwnd = net->cwnd;
1507
1508         /* JRS - reset as if the state were being changed to timeout */
1509         htcp_reset(&net->htcp_ca);
1510         net->ssthresh = htcp_recalc_ssthresh(stcb, net);
1511         net->cwnd = net->mtu;
1512         net->partial_bytes_acked = 0;
1513         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1514                 sctp_log_cwnd(stcb, net, net->cwnd - old_cwnd, SCTP_CWND_LOG_FROM_RTX);
1515         }
1516 }
1517
1518 void
1519 sctp_htcp_cwnd_update_after_fr_timer(struct sctp_inpcb *inp,
1520     struct sctp_tcb *stcb, struct sctp_nets *net)
1521 {
1522         int old_cwnd;
1523
1524         old_cwnd = net->cwnd;
1525
1526         sctp_chunk_output(inp, stcb, SCTP_OUTPUT_FROM_EARLY_FR_TMR, SCTP_SO_NOT_LOCKED);
1527         net->htcp_ca.last_cong = sctp_get_tick_count();
1528         /*
1529          * make a small adjustment to cwnd and force to CA.
1530          */
1531         if (net->cwnd > net->mtu)
1532                 /* drop down one MTU after sending */
1533                 net->cwnd -= net->mtu;
1534         if (net->cwnd < net->ssthresh)
1535                 /* still in SS move to CA */
1536                 net->ssthresh = net->cwnd - 1;
1537         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1538                 sctp_log_cwnd(stcb, net, (old_cwnd - net->cwnd), SCTP_CWND_LOG_FROM_FR);
1539         }
1540 }
1541
1542 void
1543 sctp_htcp_cwnd_update_after_ecn_echo(struct sctp_tcb *stcb,
1544     struct sctp_nets *net)
1545 {
1546         int old_cwnd;
1547
1548         old_cwnd = net->cwnd;
1549
1550         /* JRS - reset hctp as if state changed */
1551         htcp_reset(&net->htcp_ca);
1552         SCTP_STAT_INCR(sctps_ecnereducedcwnd);
1553         net->ssthresh = htcp_recalc_ssthresh(stcb, net);
1554         if (net->ssthresh < net->mtu) {
1555                 net->ssthresh = net->mtu;
1556                 /* here back off the timer as well, to slow us down */
1557                 net->RTO <<= 1;
1558         }
1559         net->cwnd = net->ssthresh;
1560         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1561                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
1562         }
1563 }