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