sys/netinet/sctp_cc_functions.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  *
   4  * Copyright (c) 2001-2007, by Cisco Systems, Inc. All rights reserved.
   5  * Copyright (c) 2008-2012, by Randall Stewart. All rights reserved.
   6  * Copyright (c) 2008-2012, by Michael Tuexen. All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions are met:
  10  *
  11  * a) Redistributions of source code must retain the above copyright notice,
  12  *    this list of conditions and the following disclaimer.
  13  *
  14  * b) Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the distribution.
  17  *
  18  * c) Neither the name of Cisco Systems, Inc. nor the names of its
  19  *    contributors may be used to endorse or promote products derived
  20  *    from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  23  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  24  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  26  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  27  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  28  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  29  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  30  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  31  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  32  * THE POSSIBILITY OF SUCH DAMAGE.
  33  */
  34
  35 #include <sys/cdefs.h>
  36 __FBSDID("$FreeBSD$");
  37
  38 #include <netinet/sctp_os.h>
  39 #include <netinet/sctp_var.h>
  40 #include <netinet/sctp_sysctl.h>
  41 #include <netinet/sctp_pcb.h>
  42 #include <netinet/sctp_header.h>
  43 #include <netinet/sctputil.h>
  44 #include <netinet/sctp_output.h>
  45 #include <netinet/sctp_input.h>
  46 #include <netinet/sctp_indata.h>
  47 #include <netinet/sctp_uio.h>
  48 #include <netinet/sctp_timer.h>
  49 #include <netinet/sctp_auth.h>
  50 #include <netinet/sctp_asconf.h>
  51 #include <netinet/sctp_kdtrace.h>
  52
  53 #define SHIFT_MPTCP_MULTI_N 40
  54 #define SHIFT_MPTCP_MULTI_Z 16
  55 #define SHIFT_MPTCP_MULTI 8
  56
  57 #ifdef KDTRACE_HOOOKS
  58 #define __dtrace
  59 #else
  60 #define __dtrace        __unused
  61 #endif
  62
  63 static void
  64 sctp_enforce_cwnd_limit(struct sctp_association *assoc, struct sctp_nets *net)
  65 {
  66         if ((assoc->max_cwnd > 0) &&
  67             (net->cwnd > assoc->max_cwnd) &&
  68             (net->cwnd > (net->mtu - sizeof(struct sctphdr)))) {
  69                 net->cwnd = assoc->max_cwnd;
  70                 if (net->cwnd < (net->mtu - sizeof(struct sctphdr))) {
  71                         net->cwnd = net->mtu - sizeof(struct sctphdr);
  72                 }
  73         }
  74 }
  75
  76 static void
  77 sctp_set_initial_cc_param(struct sctp_tcb *stcb, struct sctp_nets *net)
  78 {
  79         struct sctp_association *assoc;
  80         uint32_t cwnd_in_mtu;
  81
  82         assoc = &stcb->asoc;
  83         cwnd_in_mtu = SCTP_BASE_SYSCTL(sctp_initial_cwnd);
  84         if (cwnd_in_mtu == 0) {
  85                 /* Using 0 means that the value of RFC 4960 is used. */
  86                 net->cwnd = min((net->mtu * 4), max((2 * net->mtu), SCTP_INITIAL_CWND));
  87         } else {
  88                 /*
  89                  * We take the minimum of the burst limit and the initial
  90                  * congestion window.
  91                  */
  92                 if ((assoc->max_burst > 0) && (cwnd_in_mtu > assoc->max_burst))
  93                         cwnd_in_mtu = assoc->max_burst;
  94                 net->cwnd = (net->mtu - sizeof(struct sctphdr)) * cwnd_in_mtu;
  95         }
  96         if ((stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) ||
  97             (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV2)) {
  98                 /* In case of resource pooling initialize appropriately */
  99                 net->cwnd /= assoc->numnets;
 100                 if (net->cwnd < (net->mtu - sizeof(struct sctphdr))) {
 101                         net->cwnd = net->mtu - sizeof(struct sctphdr);
 102                 }
 103         }
 104         sctp_enforce_cwnd_limit(assoc, net);
 105         net->ssthresh = assoc->peers_rwnd;
 106         SDT_PROBE5(sctp, cwnd, net, init,
 107             stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
 108             0, net->cwnd);
 109         if (SCTP_BASE_SYSCTL(sctp_logging_level) &
 110             (SCTP_CWND_MONITOR_ENABLE | SCTP_CWND_LOGGING_ENABLE)) {
 111                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_INITIALIZATION);
 112         }
 113 }
 114
 115 static void
 116 sctp_cwnd_update_after_fr(struct sctp_tcb *stcb,
 117     struct sctp_association *asoc)
 118 {
 119         struct sctp_nets *net;
 120         uint32_t t_ssthresh, t_cwnd;
 121         uint64_t t_ucwnd_sbw;
 122
 123         /* MT FIXME: Don't compute this over and over again */
 124         t_ssthresh = 0;
 125         t_cwnd = 0;
 126         t_ucwnd_sbw = 0;
 127         if ((asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) ||
 128             (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2)) {
 129                 TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
 130                         t_ssthresh += net->ssthresh;
 131                         t_cwnd += net->cwnd;
 132                         if (net->lastsa > 0) {
 133                                 t_ucwnd_sbw += (uint64_t)net->cwnd / (uint64_t)net->lastsa;
 134                         }
 135                 }
 136                 if (t_ucwnd_sbw == 0) {
 137                         t_ucwnd_sbw = 1;
 138                 }
 139         }
 140
 141         /*-
 142          * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off > 0) &&
 143          * (net->fast_retran_loss_recovery == 0)))
 144          */
 145         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
 146                 if ((asoc->fast_retran_loss_recovery == 0) ||
 147                     (asoc->sctp_cmt_on_off > 0)) {
 148                         /* out of a RFC2582 Fast recovery window? */
 149                         if (net->net_ack > 0) {
 150                                 /*
 151                                  * per section 7.2.3, are there any
 152                                  * destinations that had a fast retransmit
 153                                  * to them. If so what we need to do is
 154                                  * adjust ssthresh and cwnd.
 155                                  */
 156                                 struct sctp_tmit_chunk *lchk;
 157                                 int old_cwnd = net->cwnd;
 158
 159                                 if ((asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) ||
 160                                     (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2)) {
 161                                         if (asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) {
 162                                                 net->ssthresh = (uint32_t)(((uint64_t)4 *
 163                                                     (uint64_t)net->mtu *
 164                                                     (uint64_t)net->ssthresh) /
 165                                                     (uint64_t)t_ssthresh);
 166                                         }
 167                                         if (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2) {
 168                                                 uint32_t srtt;
 169
 170                                                 srtt = net->lastsa;
 171                                                 /*
 172                                                  * lastsa>>3;  we don't need
 173                                                  * to devide ...
 174                                                  */
 175                                                 if (srtt == 0) {
 176                                                         srtt = 1;
 177                                                 }
 178                                                 /*
 179                                                  * Short Version => Equal to
 180                                                  * Contel Version MBe
 181                                                  */
 182                                                 net->ssthresh = (uint32_t)(((uint64_t)4 *
 183                                                     (uint64_t)net->mtu *
 184                                                     (uint64_t)net->cwnd) /
 185                                                     ((uint64_t)srtt *
 186                                                     t_ucwnd_sbw));
 187                                                  /* INCREASE FACTOR */ ;
 188                                         }
 189                                         if ((net->cwnd > t_cwnd / 2) &&
 190                                             (net->ssthresh < net->cwnd - t_cwnd / 2)) {
 191                                                 net->ssthresh = net->cwnd - t_cwnd / 2;
 192                                         }
 193                                         if (net->ssthresh < net->mtu) {
 194                                                 net->ssthresh = net->mtu;
 195                                         }
 196                                 } else {
 197                                         net->ssthresh = net->cwnd / 2;
 198                                         if (net->ssthresh < (net->mtu * 2)) {
 199                                                 net->ssthresh = 2 * net->mtu;
 200                                         }
 201                                 }
 202                                 net->cwnd = net->ssthresh;
 203                                 sctp_enforce_cwnd_limit(asoc, net);
 204                                 SDT_PROBE5(sctp, cwnd, net, fr,
 205                                     stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
 206                                     old_cwnd, net->cwnd);
 207                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 208                                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
 209                                             SCTP_CWND_LOG_FROM_FR);
 210                                 }
 211                                 lchk = TAILQ_FIRST(&asoc->send_queue);
 212
 213                                 net->partial_bytes_acked = 0;
 214                                 /* Turn on fast recovery window */
 215                                 asoc->fast_retran_loss_recovery = 1;
 216                                 if (lchk == NULL) {
 217                                         /* Mark end of the window */
 218                                         asoc->fast_recovery_tsn = asoc->sending_seq - 1;
 219                                 } else {
 220                                         asoc->fast_recovery_tsn = lchk->rec.data.tsn - 1;
 221                                 }
 222
 223                                 /*
 224                                  * CMT fast recovery -- per destination
 225                                  * recovery variable.
 226                                  */
 227                                 net->fast_retran_loss_recovery = 1;
 228
 229                                 if (lchk == NULL) {
 230                                         /* Mark end of the window */
 231                                         net->fast_recovery_tsn = asoc->sending_seq - 1;
 232                                 } else {
 233                                         net->fast_recovery_tsn = lchk->rec.data.tsn - 1;
 234                                 }
 235
 236                                 sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
 237                                     stcb->sctp_ep, stcb, net,
 238                                     SCTP_FROM_SCTP_CC_FUNCTIONS + SCTP_LOC_1);
 239                                 sctp_timer_start(SCTP_TIMER_TYPE_SEND,
 240                                     stcb->sctp_ep, stcb, net);
 241                         }
 242                 } else if (net->net_ack > 0) {
 243                         /*
 244                          * Mark a peg that we WOULD have done a cwnd
 245                          * reduction but RFC2582 prevented this action.
 246                          */
 247                         SCTP_STAT_INCR(sctps_fastretransinrtt);
 248                 }
 249         }
 250 }
 251
 252 /* Defines for instantaneous bw decisions */
 253 #define SCTP_INST_LOOSING 1     /* Losing to other flows */
 254 #define SCTP_INST_NEUTRAL 2     /* Neutral, no indication */
 255 #define SCTP_INST_GAINING 3     /* Gaining, step down possible */
 256
 257 static int
 258 cc_bw_same(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw,
 259     uint64_t rtt_offset, uint64_t vtag, uint8_t inst_ind)
 260 {
 261         uint64_t oth __dtrace, probepoint __dtrace;
 262
 263         probepoint = (((uint64_t)net->cwnd) << 32);
 264         if (net->rtt > net->cc_mod.rtcc.lbw_rtt + rtt_offset) {
 265                 /*
 266                  * rtt increased we don't update bw.. so we don't update the
 267                  * rtt either.
 268                  */
 269                 /* Probe point 5 */
 270                 probepoint |= ((5 << 16) | 1);
 271                 SDT_PROBE5(sctp, cwnd, net, rttvar,
 272                     vtag,
 273                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 274                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 275                     net->flight_size,
 276                     probepoint);
 277                 if ((net->cc_mod.rtcc.steady_step) && (inst_ind != SCTP_INST_LOOSING)) {
 278                         if (net->cc_mod.rtcc.last_step_state == 5)
 279                                 net->cc_mod.rtcc.step_cnt++;
 280                         else
 281                                 net->cc_mod.rtcc.step_cnt = 1;
 282                         net->cc_mod.rtcc.last_step_state = 5;
 283                         if ((net->cc_mod.rtcc.step_cnt == net->cc_mod.rtcc.steady_step) ||
 284                             ((net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step) &&
 285                             ((net->cc_mod.rtcc.step_cnt % net->cc_mod.rtcc.steady_step) == 0))) {
 286                                 /* Try a step down */
 287                                 oth = net->cc_mod.rtcc.vol_reduce;
 288                                 oth <<= 16;
 289                                 oth |= net->cc_mod.rtcc.step_cnt;
 290                                 oth <<= 16;
 291                                 oth |= net->cc_mod.rtcc.last_step_state;
 292                                 SDT_PROBE5(sctp, cwnd, net, rttstep,
 293                                     vtag,
 294                                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 295                                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 296                                     oth,
 297                                     probepoint);
 298                                 if (net->cwnd > (4 * net->mtu)) {
 299                                         net->cwnd -= net->mtu;
 300                                         net->cc_mod.rtcc.vol_reduce++;
 301                                 } else {
 302                                         net->cc_mod.rtcc.step_cnt = 0;
 303                                 }
 304                         }
 305                 }
 306                 return (1);
 307         }
 308         if (net->rtt < net->cc_mod.rtcc.lbw_rtt - rtt_offset) {
 309                 /*
 310                  * rtt decreased, there could be more room. we update both
 311                  * the bw and the rtt here to lock this in as a good step
 312                  * down.
 313                  */
 314                 /* Probe point 6 */
 315                 probepoint |= ((6 << 16) | 0);
 316                 SDT_PROBE5(sctp, cwnd, net, rttvar,
 317                     vtag,
 318                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 319                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 320                     net->flight_size,
 321                     probepoint);
 322                 if (net->cc_mod.rtcc.steady_step) {
 323                         oth = net->cc_mod.rtcc.vol_reduce;
 324                         oth <<= 16;
 325                         oth |= net->cc_mod.rtcc.step_cnt;
 326                         oth <<= 16;
 327                         oth |= net->cc_mod.rtcc.last_step_state;
 328                         SDT_PROBE5(sctp, cwnd, net, rttstep,
 329                             vtag,
 330                             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 331                             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 332                             oth,
 333                             probepoint);
 334                         if ((net->cc_mod.rtcc.last_step_state == 5) &&
 335                             (net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step)) {
 336                                 /* Step down worked */
 337                                 net->cc_mod.rtcc.step_cnt = 0;
 338                                 return (1);
 339                         } else {
 340                                 net->cc_mod.rtcc.last_step_state = 6;
 341                                 net->cc_mod.rtcc.step_cnt = 0;
 342                         }
 343                 }
 344                 net->cc_mod.rtcc.lbw = nbw;
 345                 net->cc_mod.rtcc.lbw_rtt = net->rtt;
 346                 net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
 347                 if (inst_ind == SCTP_INST_GAINING)
 348                         return (1);
 349                 else if (inst_ind == SCTP_INST_NEUTRAL)
 350                         return (1);
 351                 else
 352                         return (0);
 353         }
 354         /*
 355          * Ok bw and rtt remained the same .. no update to any
 356          */
 357         /* Probe point 7 */
 358         probepoint |= ((7 << 16) | net->cc_mod.rtcc.ret_from_eq);
 359         SDT_PROBE5(sctp, cwnd, net, rttvar,
 360             vtag,
 361             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 362             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 363             net->flight_size,
 364             probepoint);
 365         if ((net->cc_mod.rtcc.steady_step) && (inst_ind != SCTP_INST_LOOSING)) {
 366                 if (net->cc_mod.rtcc.last_step_state == 5)
 367                         net->cc_mod.rtcc.step_cnt++;
 368                 else
 369                         net->cc_mod.rtcc.step_cnt = 1;
 370                 net->cc_mod.rtcc.last_step_state = 5;
 371                 if ((net->cc_mod.rtcc.step_cnt == net->cc_mod.rtcc.steady_step) ||
 372                     ((net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step) &&
 373                     ((net->cc_mod.rtcc.step_cnt % net->cc_mod.rtcc.steady_step) == 0))) {
 374                         /* Try a step down */
 375                         if (net->cwnd > (4 * net->mtu)) {
 376                                 net->cwnd -= net->mtu;
 377                                 net->cc_mod.rtcc.vol_reduce++;
 378                                 return (1);
 379                         } else {
 380                                 net->cc_mod.rtcc.step_cnt = 0;
 381                         }
 382                 }
 383         }
 384         if (inst_ind == SCTP_INST_GAINING)
 385                 return (1);
 386         else if (inst_ind == SCTP_INST_NEUTRAL)
 387                 return (1);
 388         else
 389                 return ((int)net->cc_mod.rtcc.ret_from_eq);
 390 }
 391
 392 static int
 393 cc_bw_decrease(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw, uint64_t rtt_offset,
 394     uint64_t vtag, uint8_t inst_ind)
 395 {
 396         uint64_t oth __dtrace, probepoint __dtrace;
 397
 398         /* Bandwidth decreased. */
 399         probepoint = (((uint64_t)net->cwnd) << 32);
 400         if (net->rtt > net->cc_mod.rtcc.lbw_rtt + rtt_offset) {
 401                 /* rtt increased */
 402                 /* Did we add more */
 403                 if ((net->cwnd > net->cc_mod.rtcc.cwnd_at_bw_set) &&
 404                     (inst_ind != SCTP_INST_LOOSING)) {
 405                         /* We caused it maybe.. back off? */
 406                         /* PROBE POINT 1 */
 407                         probepoint |= ((1 << 16) | 1);
 408                         SDT_PROBE5(sctp, cwnd, net, rttvar,
 409                             vtag,
 410                             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 411                             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 412                             net->flight_size,
 413                             probepoint);
 414                         if (net->cc_mod.rtcc.ret_from_eq) {
 415                                 /*
 416                                  * Switch over to CA if we are less
 417                                  * aggressive
 418                                  */
 419                                 net->ssthresh = net->cwnd - 1;
 420                                 net->partial_bytes_acked = 0;
 421                         }
 422                         return (1);
 423                 }
 424                 /* Probe point 2 */
 425                 probepoint |= ((2 << 16) | 0);
 426                 SDT_PROBE5(sctp, cwnd, net, rttvar,
 427                     vtag,
 428                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 429                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 430                     net->flight_size,
 431                     probepoint);
 432                 /* Someone else - fight for more? */
 433                 if (net->cc_mod.rtcc.steady_step) {
 434                         oth = net->cc_mod.rtcc.vol_reduce;
 435                         oth <<= 16;
 436                         oth |= net->cc_mod.rtcc.step_cnt;
 437                         oth <<= 16;
 438                         oth |= net->cc_mod.rtcc.last_step_state;
 439                         SDT_PROBE5(sctp, cwnd, net, rttstep,
 440                             vtag,
 441                             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 442                             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 443                             oth,
 444                             probepoint);
 445                         /*
 446                          * Did we voluntarily give up some? if so take one
 447                          * back please
 448                          */
 449                         if ((net->cc_mod.rtcc.vol_reduce) &&
 450                             (inst_ind != SCTP_INST_GAINING)) {
 451                                 net->cwnd += net->mtu;
 452                                 sctp_enforce_cwnd_limit(&stcb->asoc, net);
 453                                 net->cc_mod.rtcc.vol_reduce--;
 454                         }
 455                         net->cc_mod.rtcc.last_step_state = 2;
 456                         net->cc_mod.rtcc.step_cnt = 0;
 457                 }
 458                 goto out_decision;
 459         } else if (net->rtt < net->cc_mod.rtcc.lbw_rtt - rtt_offset) {
 460                 /* bw & rtt decreased */
 461                 /* Probe point 3 */
 462                 probepoint |= ((3 << 16) | 0);
 463                 SDT_PROBE5(sctp, cwnd, net, rttvar,
 464                     vtag,
 465                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 466                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 467                     net->flight_size,
 468                     probepoint);
 469                 if (net->cc_mod.rtcc.steady_step) {
 470                         oth = net->cc_mod.rtcc.vol_reduce;
 471                         oth <<= 16;
 472                         oth |= net->cc_mod.rtcc.step_cnt;
 473                         oth <<= 16;
 474                         oth |= net->cc_mod.rtcc.last_step_state;
 475                         SDT_PROBE5(sctp, cwnd, net, rttstep,
 476                             vtag,
 477                             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 478                             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 479                             oth,
 480                             probepoint);
 481                         if ((net->cc_mod.rtcc.vol_reduce) &&
 482                             (inst_ind != SCTP_INST_GAINING)) {
 483                                 net->cwnd += net->mtu;
 484                                 sctp_enforce_cwnd_limit(&stcb->asoc, net);
 485                                 net->cc_mod.rtcc.vol_reduce--;
 486                         }
 487                         net->cc_mod.rtcc.last_step_state = 3;
 488                         net->cc_mod.rtcc.step_cnt = 0;
 489                 }
 490                 goto out_decision;
 491         }
 492         /* The bw decreased but rtt stayed the same */
 493         /* Probe point 4 */
 494         probepoint |= ((4 << 16) | 0);
 495         SDT_PROBE5(sctp, cwnd, net, rttvar,
 496             vtag,
 497             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 498             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 499             net->flight_size,
 500             probepoint);
 501         if (net->cc_mod.rtcc.steady_step) {
 502                 oth = net->cc_mod.rtcc.vol_reduce;
 503                 oth <<= 16;
 504                 oth |= net->cc_mod.rtcc.step_cnt;
 505                 oth <<= 16;
 506                 oth |= net->cc_mod.rtcc.last_step_state;
 507                 SDT_PROBE5(sctp, cwnd, net, rttstep,
 508                     vtag,
 509                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 510                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 511                     oth,
 512                     probepoint);
 513                 if ((net->cc_mod.rtcc.vol_reduce) &&
 514                     (inst_ind != SCTP_INST_GAINING)) {
 515                         net->cwnd += net->mtu;
 516                         sctp_enforce_cwnd_limit(&stcb->asoc, net);
 517                         net->cc_mod.rtcc.vol_reduce--;
 518                 }
 519                 net->cc_mod.rtcc.last_step_state = 4;
 520                 net->cc_mod.rtcc.step_cnt = 0;
 521         }
 522 out_decision:
 523         net->cc_mod.rtcc.lbw = nbw;
 524         net->cc_mod.rtcc.lbw_rtt = net->rtt;
 525         net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
 526         if (inst_ind == SCTP_INST_GAINING) {
 527                 return (1);
 528         } else {
 529                 return (0);
 530         }
 531 }
 532
 533 static int
 534 cc_bw_increase(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw, uint64_t vtag)
 535 {
 536         uint64_t oth __dtrace, probepoint __dtrace;
 537
 538         /*
 539          * BW increased, so update and return 0, since all actions in our
 540          * table say to do the normal CC update. Note that we pay no
 541          * attention to the inst_ind since our overall sum is increasing.
 542          */
 543         /* PROBE POINT 0 */
 544         probepoint = (((uint64_t)net->cwnd) << 32);
 545         SDT_PROBE5(sctp, cwnd, net, rttvar,
 546             vtag,
 547             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 548             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 549             net->flight_size,
 550             probepoint);
 551         if (net->cc_mod.rtcc.steady_step) {
 552                 oth = net->cc_mod.rtcc.vol_reduce;
 553                 oth <<= 16;
 554                 oth |= net->cc_mod.rtcc.step_cnt;
 555                 oth <<= 16;
 556                 oth |= net->cc_mod.rtcc.last_step_state;
 557                 SDT_PROBE5(sctp, cwnd, net, rttstep,
 558                     vtag,
 559                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 560                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 561                     oth,
 562                     probepoint);
 563                 net->cc_mod.rtcc.last_step_state = 0;
 564                 net->cc_mod.rtcc.step_cnt = 0;
 565                 net->cc_mod.rtcc.vol_reduce = 0;
 566         }
 567         net->cc_mod.rtcc.lbw = nbw;
 568         net->cc_mod.rtcc.lbw_rtt = net->rtt;
 569         net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
 570         return (0);
 571 }
 572
 573 /* RTCC Algorithm to limit growth of cwnd, return
 574  * true if you want to NOT allow cwnd growth
 575  */
 576 static int
 577 cc_bw_limit(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw)
 578 {
 579         uint64_t bw_offset, rtt_offset;
 580         uint64_t probepoint __dtrace, rtt, vtag;
 581         uint64_t bytes_for_this_rtt, inst_bw;
 582         uint64_t div, inst_off;
 583         int bw_shift;
 584         uint8_t inst_ind;
 585         int ret;
 586
 587         /*-
 588          * Here we need to see if we want
 589          * to limit cwnd growth due to increase
 590          * in overall rtt but no increase in bw.
 591          * We use the following table to figure
 592          * out what we should do. When we return
 593          * 0, cc update goes on as planned. If we
 594          * return 1, then no cc update happens and cwnd
 595          * stays where it is at.
 596          * ----------------------------------
 597          *   BW    |    RTT   | Action
 598          * *********************************
 599          *   INC   |    INC   | return 0
 600          * ----------------------------------
 601          *   INC   |    SAME  | return 0
 602          * ----------------------------------
 603          *   INC   |    DECR  | return 0
 604          * ----------------------------------
 605          *   SAME  |    INC   | return 1
 606          * ----------------------------------
 607          *   SAME  |    SAME  | return 1
 608          * ----------------------------------
 609          *   SAME  |    DECR  | return 0
 610          * ----------------------------------
 611          *   DECR  |    INC   | return 0 or 1 based on if we caused.
 612          * ----------------------------------
 613          *   DECR  |    SAME  | return 0
 614          * ----------------------------------
 615          *   DECR  |    DECR  | return 0
 616          * ----------------------------------
 617          *
 618          * We are a bit fuzz on what an increase or
 619          * decrease is. For BW it is the same if
 620          * it did not change within 1/64th. For
 621          * RTT it stayed the same if it did not
 622          * change within 1/32nd
 623          */
 624         bw_shift = SCTP_BASE_SYSCTL(sctp_rttvar_bw);
 625         rtt = stcb->asoc.my_vtag;
 626         vtag = (rtt << 32) | (((uint32_t)(stcb->sctp_ep->sctp_lport)) << 16) | (stcb->rport);
 627         probepoint = (((uint64_t)net->cwnd) << 32);
 628         rtt = net->rtt;
 629         if (net->cc_mod.rtcc.rtt_set_this_sack) {
 630                 net->cc_mod.rtcc.rtt_set_this_sack = 0;
 631                 bytes_for_this_rtt = net->cc_mod.rtcc.bw_bytes - net->cc_mod.rtcc.bw_bytes_at_last_rttc;
 632                 net->cc_mod.rtcc.bw_bytes_at_last_rttc = net->cc_mod.rtcc.bw_bytes;
 633                 if (net->rtt) {
 634                         div = net->rtt / 1000;
 635                         if (div) {
 636                                 inst_bw = bytes_for_this_rtt / div;
 637                                 inst_off = inst_bw >> bw_shift;
 638                                 if (inst_bw > nbw)
 639                                         inst_ind = SCTP_INST_GAINING;
 640                                 else if ((inst_bw + inst_off) < nbw)
 641                                         inst_ind = SCTP_INST_LOOSING;
 642                                 else
 643                                         inst_ind = SCTP_INST_NEUTRAL;
 644                                 probepoint |= ((0xb << 16) | inst_ind);
 645                         } else {
 646                                 inst_ind = net->cc_mod.rtcc.last_inst_ind;
 647                                 inst_bw = bytes_for_this_rtt / (uint64_t)(net->rtt);
 648                                 /* Can't determine do not change */
 649                                 probepoint |= ((0xc << 16) | inst_ind);
 650                         }
 651                 } else {
 652                         inst_ind = net->cc_mod.rtcc.last_inst_ind;
 653                         inst_bw = bytes_for_this_rtt;
 654                         /* Can't determine do not change */
 655                         probepoint |= ((0xd << 16) | inst_ind);
 656                 }
 657                 SDT_PROBE5(sctp, cwnd, net, rttvar,
 658                     vtag,
 659                     ((nbw << 32) | inst_bw),
 660                     ((net->cc_mod.rtcc.lbw_rtt << 32) | rtt),
 661                     net->flight_size,
 662                     probepoint);
 663         } else {
 664                 /* No rtt measurement, use last one */
 665                 inst_ind = net->cc_mod.rtcc.last_inst_ind;
 666         }
 667         bw_offset = net->cc_mod.rtcc.lbw >> bw_shift;
 668         if (nbw > net->cc_mod.rtcc.lbw + bw_offset) {
 669                 ret = cc_bw_increase(stcb, net, nbw, vtag);
 670                 goto out;
 671         }
 672         rtt_offset = net->cc_mod.rtcc.lbw_rtt >> SCTP_BASE_SYSCTL(sctp_rttvar_rtt);
 673         if (nbw < net->cc_mod.rtcc.lbw - bw_offset) {
 674                 ret = cc_bw_decrease(stcb, net, nbw, rtt_offset, vtag, inst_ind);
 675                 goto out;
 676         }
 677         /*
 678          * If we reach here then we are in a situation where the bw stayed
 679          * the same.
 680          */
 681         ret = cc_bw_same(stcb, net, nbw, rtt_offset, vtag, inst_ind);
 682 out:
 683         net->cc_mod.rtcc.last_inst_ind = inst_ind;
 684         return (ret);
 685 }
 686
 687 static void
 688 sctp_cwnd_update_after_sack_common(struct sctp_tcb *stcb,
 689     struct sctp_association *asoc,
 690     int accum_moved, int reneged_all SCTP_UNUSED, int will_exit, int use_rtcc)
 691 {
 692         struct sctp_nets *net;
 693         int old_cwnd __dtrace;
 694         uint32_t t_ssthresh, incr;
 695         uint64_t t_ucwnd_sbw;
 696         uint64_t t_path_mptcp;
 697         uint64_t mptcp_like_alpha;
 698         uint32_t srtt;
 699         uint64_t max_path;
 700
 701         /* MT FIXME: Don't compute this over and over again */
 702         t_ssthresh = 0;
 703         t_ucwnd_sbw = 0;
 704         t_path_mptcp = 0;
 705         mptcp_like_alpha = 1;
 706         if ((stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) ||
 707             (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV2) ||
 708             (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_MPTCP)) {
 709                 max_path = 0;
 710                 TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
 711                         t_ssthresh += net->ssthresh;
 712                         /* lastsa>>3;  we don't need to devide ... */
 713                         srtt = net->lastsa;
 714                         if (srtt > 0) {
 715                                 uint64_t tmp;
 716
 717                                 t_ucwnd_sbw += (uint64_t)net->cwnd / (uint64_t)srtt;
 718                                 t_path_mptcp += (((uint64_t)net->cwnd) << SHIFT_MPTCP_MULTI_Z) /
 719                                     (((uint64_t)net->mtu) * (uint64_t)srtt);
 720                                 tmp = (((uint64_t)net->cwnd) << SHIFT_MPTCP_MULTI_N) /
 721                                     ((uint64_t)net->mtu * (uint64_t)(srtt * srtt));
 722                                 if (tmp > max_path) {
 723                                         max_path = tmp;
 724                                 }
 725                         }
 726                 }
 727                 if (t_path_mptcp > 0) {
 728                         mptcp_like_alpha = max_path / (t_path_mptcp * t_path_mptcp);
 729                 } else {
 730                         mptcp_like_alpha = 1;
 731                 }
 732         }
 733         if (t_ssthresh == 0) {
 734                 t_ssthresh = 1;
 735         }
 736         if (t_ucwnd_sbw == 0) {
 737                 t_ucwnd_sbw = 1;
 738         }
 739         /******************************/
 740         /* update cwnd and Early FR   */
 741         /******************************/
 742         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
 743 #ifdef JANA_CMT_FAST_RECOVERY
 744                 /*
 745                  * CMT fast recovery code. Need to debug.
 746                  */
 747                 if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
 748                         if (SCTP_TSN_GE(asoc->last_acked_seq, net->fast_recovery_tsn) ||
 749                             SCTP_TSN_GE(net->pseudo_cumack, net->fast_recovery_tsn)) {
 750                                 net->will_exit_fast_recovery = 1;
 751                         }
 752                 }
 753 #endif
 754                 /* if nothing was acked on this destination skip it */
 755                 if (net->net_ack == 0) {
 756                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 757                                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
 758                         }
 759                         continue;
 760                 }
 761 #ifdef JANA_CMT_FAST_RECOVERY
 762                 /*
 763                  * CMT fast recovery code
 764                  */
 765                 /*
 766                  * if (sctp_cmt_on_off > 0 && net->fast_retran_loss_recovery
 767                  * && net->will_exit_fast_recovery == 0) { @@@ Do something
 768                  * } else if (sctp_cmt_on_off == 0 &&
 769                  * asoc->fast_retran_loss_recovery && will_exit == 0) {
 770                  */
 771 #endif
 772
 773                 if (asoc->fast_retran_loss_recovery &&
 774                     (will_exit == 0) &&
 775                     (asoc->sctp_cmt_on_off == 0)) {
 776                         /*
 777                          * If we are in loss recovery we skip any cwnd
 778                          * update
 779                          */
 780                         return;
 781                 }
 782                 /*
 783                  * Did any measurements go on for this network?
 784                  */
 785                 if (use_rtcc && (net->cc_mod.rtcc.tls_needs_set > 0)) {
 786                         uint64_t nbw;
 787
 788                         /*
 789                          * At this point our bw_bytes has been updated by
 790                          * incoming sack information.
 791                          *
 792                          * But our bw may not yet be set.
 793                          *
 794                          */
 795                         if ((net->cc_mod.rtcc.new_tot_time / 1000) > 0) {
 796                                 nbw = net->cc_mod.rtcc.bw_bytes / (net->cc_mod.rtcc.new_tot_time / 1000);
 797                         } else {
 798                                 nbw = net->cc_mod.rtcc.bw_bytes;
 799                         }
 800                         if (net->cc_mod.rtcc.lbw) {
 801                                 if (cc_bw_limit(stcb, net, nbw)) {
 802                                         /* Hold here, no update */
 803                                         continue;
 804                                 }
 805                         } else {
 806                                 uint64_t vtag __dtrace, probepoint __dtrace;
 807
 808                                 probepoint = (((uint64_t)net->cwnd) << 32);
 809                                 probepoint |= ((0xa << 16) | 0);
 810                                 vtag = (net->rtt << 32) |
 811                                     (((uint32_t)(stcb->sctp_ep->sctp_lport)) << 16) |
 812                                     (stcb->rport);
 813
 814                                 SDT_PROBE5(sctp, cwnd, net, rttvar,
 815                                     vtag,
 816                                     nbw,
 817                                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 818                                     net->flight_size,
 819                                     probepoint);
 820                                 net->cc_mod.rtcc.lbw = nbw;
 821                                 net->cc_mod.rtcc.lbw_rtt = net->rtt;
 822                                 if (net->cc_mod.rtcc.rtt_set_this_sack) {
 823                                         net->cc_mod.rtcc.rtt_set_this_sack = 0;
 824                                         net->cc_mod.rtcc.bw_bytes_at_last_rttc = net->cc_mod.rtcc.bw_bytes;
 825                                 }
 826                         }
 827                 }
 828                 /*
 829                  * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
 830                  * moved.
 831                  */
 832                 if (accum_moved ||
 833                     ((asoc->sctp_cmt_on_off > 0) && net->new_pseudo_cumack)) {
 834                         /* If the cumulative ack moved we can proceed */
 835                         if (net->cwnd <= net->ssthresh) {
 836                                 /* We are in slow start */
 837                                 if (net->flight_size + net->net_ack >= net->cwnd) {
 838                                         uint32_t limit;
 839
 840                                         old_cwnd = net->cwnd;
 841                                         switch (asoc->sctp_cmt_on_off) {
 842                                         case SCTP_CMT_RPV1:
 843                                                 limit = (uint32_t)(((uint64_t)net->mtu *
 844                                                     (uint64_t)SCTP_BASE_SYSCTL(sctp_L2_abc_variable) *
 845                                                     (uint64_t)net->ssthresh) /
 846                                                     (uint64_t)t_ssthresh);
 847                                                 incr = (uint32_t)(((uint64_t)net->net_ack *
 848                                                     (uint64_t)net->ssthresh) /
 849                                                     (uint64_t)t_ssthresh);
 850                                                 if (incr > limit) {
 851                                                         incr = limit;
 852                                                 }
 853                                                 if (incr == 0) {
 854                                                         incr = 1;
 855                                                 }
 856                                                 break;
 857                                         case SCTP_CMT_RPV2:
 858                                                 /*
 859                                                  * lastsa>>3;  we don't need
 860                                                  * to divide ...
 861                                                  */
 862                                                 srtt = net->lastsa;
 863                                                 if (srtt == 0) {
 864                                                         srtt = 1;
 865                                                 }
 866                                                 limit = (uint32_t)(((uint64_t)net->mtu *
 867                                                     (uint64_t)SCTP_BASE_SYSCTL(sctp_L2_abc_variable) *
 868                                                     (uint64_t)net->cwnd) /
 869                                                     ((uint64_t)srtt * t_ucwnd_sbw));
 870                                                 /* INCREASE FACTOR */
 871                                                 incr = (uint32_t)(((uint64_t)net->net_ack *
 872                                                     (uint64_t)net->cwnd) /
 873                                                     ((uint64_t)srtt * t_ucwnd_sbw));
 874                                                 /* INCREASE FACTOR */
 875                                                 if (incr > limit) {
 876                                                         incr = limit;
 877                                                 }
 878                                                 if (incr == 0) {
 879                                                         incr = 1;
 880                                                 }
 881                                                 break;
 882                                         case SCTP_CMT_MPTCP:
 883                                                 limit = (uint32_t)(((uint64_t)net->mtu *
 884                                                     mptcp_like_alpha *
 885                                                     (uint64_t)SCTP_BASE_SYSCTL(sctp_L2_abc_variable)) >>
 886                                                     SHIFT_MPTCP_MULTI);
 887                                                 incr = (uint32_t)(((uint64_t)net->net_ack *
 888                                                     mptcp_like_alpha) >>
 889                                                     SHIFT_MPTCP_MULTI);
 890                                                 if (incr > limit) {
 891                                                         incr = limit;
 892                                                 }
 893                                                 if (incr > net->net_ack) {
 894                                                         incr = net->net_ack;
 895                                                 }
 896                                                 if (incr > net->mtu) {
 897                                                         incr = net->mtu;
 898                                                 }
 899                                                 break;
 900                                         default:
 901                                                 incr = net->net_ack;
 902                                                 if (incr > net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable)) {
 903                                                         incr = net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable);
 904                                                 }
 905                                                 break;
 906                                         }
 907                                         net->cwnd += incr;
 908                                         sctp_enforce_cwnd_limit(asoc, net);
 909                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 910                                                 sctp_log_cwnd(stcb, net, incr,
 911                                                     SCTP_CWND_LOG_FROM_SS);
 912                                         }
 913                                         SDT_PROBE5(sctp, cwnd, net, ack,
 914                                             stcb->asoc.my_vtag,
 915                                             ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
 916                                             net,
 917                                             old_cwnd, net->cwnd);
 918                                 } else {
 919                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 920                                                 sctp_log_cwnd(stcb, net, net->net_ack,
 921                                                     SCTP_CWND_LOG_NOADV_SS);
 922                                         }
 923                                 }
 924                         } else {
 925                                 /* We are in congestion avoidance */
 926                                 /*
 927                                  * Add to pba
 928                                  */
 929                                 net->partial_bytes_acked += net->net_ack;
 930
 931                                 if ((net->flight_size + net->net_ack >= net->cwnd) &&
 932                                     (net->partial_bytes_acked >= net->cwnd)) {
 933                                         net->partial_bytes_acked -= net->cwnd;
 934                                         old_cwnd = net->cwnd;
 935                                         switch (asoc->sctp_cmt_on_off) {
 936                                         case SCTP_CMT_RPV1:
 937                                                 incr = (uint32_t)(((uint64_t)net->mtu *
 938                                                     (uint64_t)net->ssthresh) /
 939                                                     (uint64_t)t_ssthresh);
 940                                                 if (incr == 0) {
 941                                                         incr = 1;
 942                                                 }
 943                                                 break;
 944                                         case SCTP_CMT_RPV2:
 945                                                 /*
 946                                                  * lastsa>>3;  we don't need
 947                                                  * to divide ...
 948                                                  */
 949                                                 srtt = net->lastsa;
 950                                                 if (srtt == 0) {
 951                                                         srtt = 1;
 952                                                 }
 953                                                 incr = (uint32_t)((uint64_t)net->mtu *
 954                                                     (uint64_t)net->cwnd /
 955                                                     ((uint64_t)srtt *
 956                                                     t_ucwnd_sbw));
 957                                                 /* INCREASE FACTOR */
 958                                                 if (incr == 0) {
 959                                                         incr = 1;
 960                                                 }
 961                                                 break;
 962                                         case SCTP_CMT_MPTCP:
 963                                                 incr = (uint32_t)((mptcp_like_alpha *
 964                                                     (uint64_t)net->cwnd) >>
 965                                                     SHIFT_MPTCP_MULTI);
 966                                                 if (incr > net->mtu) {
 967                                                         incr = net->mtu;
 968                                                 }
 969                                                 break;
 970                                         default:
 971                                                 incr = net->mtu;
 972                                                 break;
 973                                         }
 974                                         net->cwnd += incr;
 975                                         sctp_enforce_cwnd_limit(asoc, net);
 976                                         SDT_PROBE5(sctp, cwnd, net, ack,
 977                                             stcb->asoc.my_vtag,
 978                                             ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
 979                                             net,
 980                                             old_cwnd, net->cwnd);
 981                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 982                                                 sctp_log_cwnd(stcb, net, net->mtu,
 983                                                     SCTP_CWND_LOG_FROM_CA);
 984                                         }
 985                                 } else {
 986                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 987                                                 sctp_log_cwnd(stcb, net, net->net_ack,
 988                                                     SCTP_CWND_LOG_NOADV_CA);
 989                                         }
 990                                 }
 991                         }
 992                 } else {
 993                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 994                                 sctp_log_cwnd(stcb, net, net->mtu,
 995                                     SCTP_CWND_LOG_NO_CUMACK);
 996                         }
 997                 }
 998         }
 999 }
1000
1001 static void
1002 sctp_cwnd_update_exit_pf_common(struct sctp_tcb *stcb, struct sctp_nets *net)
1003 {
1004         int old_cwnd __dtrace;
1005
1006         old_cwnd = net->cwnd;
1007         net->cwnd = net->mtu;
1008         SDT_PROBE5(sctp, cwnd, net, ack,
1009             stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
1010             old_cwnd, net->cwnd);
1011         SCTPDBG(SCTP_DEBUG_INDATA1, "Destination %p moved from PF to reachable with cwnd %d.\n",
1012             (void *)net, net->cwnd);
1013 }
1014
1015 static void
1016 sctp_cwnd_update_after_timeout(struct sctp_tcb *stcb, struct sctp_nets *net)
1017 {
1018         int old_cwnd = net->cwnd;
1019         uint32_t t_ssthresh, t_cwnd;
1020         uint64_t t_ucwnd_sbw;
1021
1022         /* MT FIXME: Don't compute this over and over again */
1023         t_ssthresh = 0;
1024         t_cwnd = 0;
1025         if ((stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) ||
1026             (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV2)) {
1027                 struct sctp_nets *lnet;
1028                 uint32_t srtt;
1029
1030                 t_ucwnd_sbw = 0;
1031                 TAILQ_FOREACH(lnet, &stcb->asoc.nets, sctp_next) {
1032                         t_ssthresh += lnet->ssthresh;
1033                         t_cwnd += lnet->cwnd;
1034                         srtt = lnet->lastsa;
1035                         /* lastsa>>3;  we don't need to divide ... */
1036                         if (srtt > 0) {
1037                                 t_ucwnd_sbw += (uint64_t)lnet->cwnd / (uint64_t)srtt;
1038                         }
1039                 }
1040                 if (t_ssthresh < 1) {
1041                         t_ssthresh = 1;
1042                 }
1043                 if (t_ucwnd_sbw < 1) {
1044                         t_ucwnd_sbw = 1;
1045                 }
1046                 if (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) {
1047                         net->ssthresh = (uint32_t)(((uint64_t)4 *
1048                             (uint64_t)net->mtu *
1049                             (uint64_t)net->ssthresh) /
1050                             (uint64_t)t_ssthresh);
1051                 } else {
1052                         uint64_t cc_delta;
1053
1054                         srtt = net->lastsa;
1055                         /* lastsa>>3;  we don't need to divide ... */
1056                         if (srtt == 0) {
1057                                 srtt = 1;
1058                         }
1059                         cc_delta = t_ucwnd_sbw * (uint64_t)srtt / 2;
1060                         if (cc_delta < t_cwnd) {
1061                                 net->ssthresh = (uint32_t)((uint64_t)t_cwnd - cc_delta);
1062                         } else {
1063                                 net->ssthresh = net->mtu;
1064                         }
1065                 }
1066                 if ((net->cwnd > t_cwnd / 2) &&
1067                     (net->ssthresh < net->cwnd - t_cwnd / 2)) {
1068                         net->ssthresh = net->cwnd - t_cwnd / 2;
1069                 }
1070                 if (net->ssthresh < net->mtu) {
1071                         net->ssthresh = net->mtu;
1072                 }
1073         } else {
1074                 net->ssthresh = max(net->cwnd / 2, 4 * net->mtu);
1075         }
1076         net->cwnd = net->mtu;
1077         net->partial_bytes_acked = 0;
1078         SDT_PROBE5(sctp, cwnd, net, to,
1079             stcb->asoc.my_vtag,
1080             ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
1081             net,
1082             old_cwnd, net->cwnd);
1083         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1084                 sctp_log_cwnd(stcb, net, net->cwnd - old_cwnd, SCTP_CWND_LOG_FROM_RTX);
1085         }
1086 }
1087
1088 static void
1089 sctp_cwnd_update_after_ecn_echo_common(struct sctp_tcb *stcb, struct sctp_nets *net,
1090     int in_window, int num_pkt_lost, int use_rtcc)
1091 {
1092         int old_cwnd = net->cwnd;
1093
1094         if ((use_rtcc) && (net->lan_type == SCTP_LAN_LOCAL) && (net->cc_mod.rtcc.use_dccc_ecn)) {
1095                 /* Data center Congestion Control */
1096                 if (in_window == 0) {
1097                         /*
1098                          * Go to CA with the cwnd at the point we sent the
1099                          * TSN that was marked with a CE.
1100                          */
1101                         if (net->ecn_prev_cwnd < net->cwnd) {
1102                                 /* Restore to prev cwnd */
1103                                 net->cwnd = net->ecn_prev_cwnd - (net->mtu * num_pkt_lost);
1104                         } else {
1105                                 /* Just cut in 1/2 */
1106                                 net->cwnd /= 2;
1107                         }
1108                         /* Drop to CA */
1109                         net->ssthresh = net->cwnd - (num_pkt_lost * net->mtu);
1110                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1111                                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
1112                         }
1113                 } else {
1114                         /*
1115                          * Further tuning down required over the drastic
1116                          * original cut
1117                          */
1118                         net->ssthresh -= (net->mtu * num_pkt_lost);
1119                         net->cwnd -= (net->mtu * num_pkt_lost);
1120                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1121                                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
1122                         }
1123                 }
1124                 SCTP_STAT_INCR(sctps_ecnereducedcwnd);
1125         } else {
1126                 if (in_window == 0) {
1127                         SCTP_STAT_INCR(sctps_ecnereducedcwnd);
1128                         net->ssthresh = net->cwnd / 2;
1129                         if (net->ssthresh < net->mtu) {
1130                                 net->ssthresh = net->mtu;
1131                                 /*
1132                                  * here back off the timer as well, to slow
1133                                  * us down
1134                                  */
1135                                 net->RTO <<= 1;
1136                         }
1137                         net->cwnd = net->ssthresh;
1138                         SDT_PROBE5(sctp, cwnd, net, ecn,
1139                             stcb->asoc.my_vtag,
1140                             ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
1141                             net,
1142                             old_cwnd, net->cwnd);
1143                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1144                                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
1145                         }
1146                 }
1147         }
1148
1149 }
1150
1151 static void
1152 sctp_cwnd_update_after_packet_dropped(struct sctp_tcb *stcb,
1153     struct sctp_nets *net, struct sctp_pktdrop_chunk *cp,
1154     uint32_t *bottle_bw, uint32_t *on_queue)
1155 {
1156         uint32_t bw_avail;
1157         unsigned int incr;
1158         int old_cwnd = net->cwnd;
1159
1160         /* get bottle neck bw */
1161         *bottle_bw = ntohl(cp->bottle_bw);
1162         /* and whats on queue */
1163         *on_queue = ntohl(cp->current_onq);
1164         /*
1165          * adjust the on-queue if our flight is more it could be that the
1166          * router has not yet gotten data "in-flight" to it
1167          */
1168         if (*on_queue < net->flight_size) {
1169                 *on_queue = net->flight_size;
1170         }
1171         /* rtt is measured in micro seconds, bottle_bw in bytes per second */
1172         bw_avail = (uint32_t)(((uint64_t)(*bottle_bw) * net->rtt) / (uint64_t)1000000);
1173         if (bw_avail > *bottle_bw) {
1174                 /*
1175                  * Cap the growth to no more than the bottle neck. This can
1176                  * happen as RTT slides up due to queues. It also means if
1177                  * you have more than a 1 second RTT with a empty queue you
1178                  * will be limited to the bottle_bw per second no matter if
1179                  * other points have 1/2 the RTT and you could get more
1180                  * out...
1181                  */
1182                 bw_avail = *bottle_bw;
1183         }
1184         if (*on_queue > bw_avail) {
1185                 /*
1186                  * No room for anything else don't allow anything else to be
1187                  * "added to the fire".
1188                  */
1189                 int seg_inflight, seg_onqueue, my_portion;
1190
1191                 net->partial_bytes_acked = 0;
1192                 /* how much are we over queue size? */
1193                 incr = *on_queue - bw_avail;
1194                 if (stcb->asoc.seen_a_sack_this_pkt) {
1195                         /*
1196                          * undo any cwnd adjustment that the sack might have
1197                          * made
1198                          */
1199                         net->cwnd = net->prev_cwnd;
1200                 }
1201                 /* Now how much of that is mine? */
1202                 seg_inflight = net->flight_size / net->mtu;
1203                 seg_onqueue = *on_queue / net->mtu;
1204                 my_portion = (incr * seg_inflight) / seg_onqueue;
1205
1206                 /* Have I made an adjustment already */
1207                 if (net->cwnd > net->flight_size) {
1208                         /*
1209                          * for this flight I made an adjustment we need to
1210                          * decrease the portion by a share our previous
1211                          * adjustment.
1212                          */
1213                         int diff_adj;
1214
1215                         diff_adj = net->cwnd - net->flight_size;
1216                         if (diff_adj > my_portion)
1217                                 my_portion = 0;
1218                         else
1219                                 my_portion -= diff_adj;
1220                 }
1221                 /*
1222                  * back down to the previous cwnd (assume we have had a sack
1223                  * before this packet). minus what ever portion of the
1224                  * overage is my fault.
1225                  */
1226                 net->cwnd -= my_portion;
1227
1228                 /* we will NOT back down more than 1 MTU */
1229                 if (net->cwnd <= net->mtu) {
1230                         net->cwnd = net->mtu;
1231                 }
1232                 /* force into CA */
1233                 net->ssthresh = net->cwnd - 1;
1234         } else {
1235                 /*
1236                  * Take 1/4 of the space left or max burst up .. whichever
1237                  * is less.
1238                  */
1239                 incr = (bw_avail - *on_queue) >> 2;
1240                 if ((stcb->asoc.max_burst > 0) &&
1241                     (stcb->asoc.max_burst * net->mtu < incr)) {
1242                         incr = stcb->asoc.max_burst * net->mtu;
1243                 }
1244                 net->cwnd += incr;
1245         }
1246         if (net->cwnd > bw_avail) {
1247                 /* We can't exceed the pipe size */
1248                 net->cwnd = bw_avail;
1249         }
1250         if (net->cwnd < net->mtu) {
1251                 /* We always have 1 MTU */
1252                 net->cwnd = net->mtu;
1253         }
1254         sctp_enforce_cwnd_limit(&stcb->asoc, net);
1255         if (net->cwnd - old_cwnd != 0) {
1256                 /* log only changes */
1257                 SDT_PROBE5(sctp, cwnd, net, pd,
1258                     stcb->asoc.my_vtag,
1259                     ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
1260                     net,
1261                     old_cwnd, net->cwnd);
1262                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1263                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
1264                             SCTP_CWND_LOG_FROM_SAT);
1265                 }
1266         }
1267 }
1268
1269 static void
1270 sctp_cwnd_update_after_output(struct sctp_tcb *stcb,
1271     struct sctp_nets *net, int burst_limit)
1272 {
1273         int old_cwnd = net->cwnd;
1274
1275         if (net->ssthresh < net->cwnd)
1276                 net->ssthresh = net->cwnd;
1277         if (burst_limit) {
1278                 net->cwnd = (net->flight_size + (burst_limit * net->mtu));
1279                 sctp_enforce_cwnd_limit(&stcb->asoc, net);
1280                 SDT_PROBE5(sctp, cwnd, net, bl,
1281                     stcb->asoc.my_vtag,
1282                     ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
1283                     net,
1284                     old_cwnd, net->cwnd);
1285                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1286                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_BRST);
1287                 }
1288         }
1289 }
1290
1291 static void
1292 sctp_cwnd_update_after_sack(struct sctp_tcb *stcb,
1293     struct sctp_association *asoc,
1294     int accum_moved, int reneged_all, int will_exit)
1295 {
1296         /* Passing a zero argument in last disables the rtcc algorithm */
1297         sctp_cwnd_update_after_sack_common(stcb, asoc, accum_moved, reneged_all, will_exit, 0);
1298 }
1299
1300 static void
1301 sctp_cwnd_update_after_ecn_echo(struct sctp_tcb *stcb, struct sctp_nets *net,
1302     int in_window, int num_pkt_lost)
1303 {
1304         /* Passing a zero argument in last disables the rtcc algorithm */
1305         sctp_cwnd_update_after_ecn_echo_common(stcb, net, in_window, num_pkt_lost, 0);
1306 }
1307
1308 /* Here starts the RTCCVAR type CC invented by RRS which
1309  * is a slight mod to RFC2581. We reuse a common routine or
1310  * two since these algorithms are so close and need to
1311  * remain the same.
1312  */
1313 static void
1314 sctp_cwnd_update_rtcc_after_ecn_echo(struct sctp_tcb *stcb, struct sctp_nets *net,
1315     int in_window, int num_pkt_lost)
1316 {
1317         sctp_cwnd_update_after_ecn_echo_common(stcb, net, in_window, num_pkt_lost, 1);
1318 }
1319
1320 static void
1321 sctp_cwnd_update_rtcc_tsn_acknowledged(struct sctp_nets *net,
1322     struct sctp_tmit_chunk *tp1)
1323 {
1324         net->cc_mod.rtcc.bw_bytes += tp1->send_size;
1325 }
1326
1327 static void
1328 sctp_cwnd_prepare_rtcc_net_for_sack(struct sctp_tcb *stcb SCTP_UNUSED,
1329     struct sctp_nets *net)
1330 {
1331         if (net->cc_mod.rtcc.tls_needs_set > 0) {
1332                 /* We had a bw measurement going on */
1333                 struct timeval ltls;
1334
1335                 SCTP_GETPTIME_TIMEVAL(&ltls);
1336                 timevalsub(&ltls, &net->cc_mod.rtcc.tls);
1337                 net->cc_mod.rtcc.new_tot_time = (ltls.tv_sec * 1000000) + ltls.tv_usec;
1338         }
1339 }
1340
1341 static void
1342 sctp_cwnd_new_rtcc_transmission_begins(struct sctp_tcb *stcb,
1343     struct sctp_nets *net)
1344 {
1345         uint64_t vtag __dtrace, probepoint __dtrace;
1346
1347         if (net->cc_mod.rtcc.lbw) {
1348                 /* Clear the old bw.. we went to 0 in-flight */
1349                 vtag = (net->rtt << 32) | (((uint32_t)(stcb->sctp_ep->sctp_lport)) << 16) |
1350                     (stcb->rport);
1351                 probepoint = (((uint64_t)net->cwnd) << 32);
1352                 /* Probe point 8 */
1353                 probepoint |= ((8 << 16) | 0);
1354                 SDT_PROBE5(sctp, cwnd, net, rttvar,
1355                     vtag,
1356                     ((net->cc_mod.rtcc.lbw << 32) | 0),
1357                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
1358                     net->flight_size,
1359                     probepoint);
1360                 net->cc_mod.rtcc.lbw_rtt = 0;
1361                 net->cc_mod.rtcc.cwnd_at_bw_set = 0;
1362                 net->cc_mod.rtcc.lbw = 0;
1363                 net->cc_mod.rtcc.bw_bytes_at_last_rttc = 0;
1364                 net->cc_mod.rtcc.vol_reduce = 0;
1365                 net->cc_mod.rtcc.bw_tot_time = 0;
1366                 net->cc_mod.rtcc.bw_bytes = 0;
1367                 net->cc_mod.rtcc.tls_needs_set = 0;
1368                 if (net->cc_mod.rtcc.steady_step) {
1369                         net->cc_mod.rtcc.vol_reduce = 0;
1370                         net->cc_mod.rtcc.step_cnt = 0;
1371                         net->cc_mod.rtcc.last_step_state = 0;
1372                 }
1373                 if (net->cc_mod.rtcc.ret_from_eq) {
1374                         /* less aggressive one - reset cwnd too */
1375                         uint32_t cwnd_in_mtu, cwnd;
1376
1377                         cwnd_in_mtu = SCTP_BASE_SYSCTL(sctp_initial_cwnd);
1378                         if (cwnd_in_mtu == 0) {
1379                                 /*
1380                                  * Using 0 means that the value of RFC 4960
1381                                  * is used.
1382                                  */
1383                                 cwnd = min((net->mtu * 4), max((2 * net->mtu), SCTP_INITIAL_CWND));
1384                         } else {
1385                                 /*
1386                                  * We take the minimum of the burst limit
1387                                  * and the initial congestion window.
1388                                  */
1389                                 if ((stcb->asoc.max_burst > 0) && (cwnd_in_mtu > stcb->asoc.max_burst))
1390                                         cwnd_in_mtu = stcb->asoc.max_burst;
1391                                 cwnd = (net->mtu - sizeof(struct sctphdr)) * cwnd_in_mtu;
1392                         }
1393                         if (net->cwnd > cwnd) {
1394                                 /*
1395                                  * Only set if we are not a timeout (i.e.
1396                                  * down to 1 mtu)
1397                                  */
1398                                 net->cwnd = cwnd;
1399                         }
1400                 }
1401         }
1402 }
1403
1404 static void
1405 sctp_set_rtcc_initial_cc_param(struct sctp_tcb *stcb,
1406     struct sctp_nets *net)
1407 {
1408 #ifdef KDTRACE_HOOOKS
1409         uint64_t vtag, probepoint;
1410 #else
1411         uint64_t vtag __unused, probepoint __unused;
1412 #endif
1413
1414         sctp_set_initial_cc_param(stcb, net);
1415         stcb->asoc.use_precise_time = 1;
1416         probepoint = (((uint64_t)net->cwnd) << 32);
1417         probepoint |= ((9 << 16) | 0);
1418         vtag = (net->rtt << 32) |
1419             (((uint32_t)(stcb->sctp_ep->sctp_lport)) << 16) |
1420             (stcb->rport);
1421         SDT_PROBE5(sctp, cwnd, net, rttvar,
1422             vtag,
1423             0,
1424             0,
1425             0,
1426             probepoint);
1427         net->cc_mod.rtcc.lbw_rtt = 0;
1428         net->cc_mod.rtcc.cwnd_at_bw_set = 0;
1429         net->cc_mod.rtcc.vol_reduce = 0;
1430         net->cc_mod.rtcc.lbw = 0;
1431         net->cc_mod.rtcc.vol_reduce = 0;
1432         net->cc_mod.rtcc.bw_bytes_at_last_rttc = 0;
1433         net->cc_mod.rtcc.bw_tot_time = 0;
1434         net->cc_mod.rtcc.bw_bytes = 0;
1435         net->cc_mod.rtcc.tls_needs_set = 0;
1436         net->cc_mod.rtcc.ret_from_eq = SCTP_BASE_SYSCTL(sctp_rttvar_eqret);
1437         net->cc_mod.rtcc.steady_step = SCTP_BASE_SYSCTL(sctp_steady_step);
1438         net->cc_mod.rtcc.use_dccc_ecn = SCTP_BASE_SYSCTL(sctp_use_dccc_ecn);
1439         net->cc_mod.rtcc.step_cnt = 0;
1440         net->cc_mod.rtcc.last_step_state = 0;
1441 }
1442
1443 static int
1444 sctp_cwnd_rtcc_socket_option(struct sctp_tcb *stcb, int setorget,
1445     struct sctp_cc_option *cc_opt)
1446 {
1447         struct sctp_nets *net;
1448
1449         if (setorget == 1) {
1450                 /* a set */
1451                 if (cc_opt->option == SCTP_CC_OPT_RTCC_SETMODE) {
1452                         if ((cc_opt->aid_value.assoc_value != 0) &&
1453                             (cc_opt->aid_value.assoc_value != 1)) {
1454                                 return (EINVAL);
1455                         }
1456                         TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
1457                                 net->cc_mod.rtcc.ret_from_eq = cc_opt->aid_value.assoc_value;
1458                         }
1459                 } else if (cc_opt->option == SCTP_CC_OPT_USE_DCCC_ECN) {
1460                         if ((cc_opt->aid_value.assoc_value != 0) &&
1461                             (cc_opt->aid_value.assoc_value != 1)) {
1462                                 return (EINVAL);
1463                         }
1464                         TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
1465                                 net->cc_mod.rtcc.use_dccc_ecn = cc_opt->aid_value.assoc_value;
1466                         }
1467                 } else if (cc_opt->option == SCTP_CC_OPT_STEADY_STEP) {
1468                         TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
1469                                 net->cc_mod.rtcc.steady_step = cc_opt->aid_value.assoc_value;
1470                         }
1471                 } else {
1472                         return (EINVAL);
1473                 }
1474         } else {
1475                 /* a get */
1476                 if (cc_opt->option == SCTP_CC_OPT_RTCC_SETMODE) {
1477                         net = TAILQ_FIRST(&stcb->asoc.nets);
1478                         if (net == NULL) {
1479                                 return (EFAULT);
1480                         }
1481                         cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.ret_from_eq;
1482                 } else if (cc_opt->option == SCTP_CC_OPT_USE_DCCC_ECN) {
1483                         net = TAILQ_FIRST(&stcb->asoc.nets);
1484                         if (net == NULL) {
1485                                 return (EFAULT);
1486                         }
1487                         cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.use_dccc_ecn;
1488                 } else if (cc_opt->option == SCTP_CC_OPT_STEADY_STEP) {
1489                         net = TAILQ_FIRST(&stcb->asoc.nets);
1490                         if (net == NULL) {
1491                                 return (EFAULT);
1492                         }
1493                         cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.steady_step;
1494                 } else {
1495                         return (EINVAL);
1496                 }
1497         }
1498         return (0);
1499 }
1500
1501 static void
1502 sctp_cwnd_update_rtcc_packet_transmitted(struct sctp_tcb *stcb SCTP_UNUSED,
1503     struct sctp_nets *net)
1504 {
1505         if (net->cc_mod.rtcc.tls_needs_set == 0) {
1506                 SCTP_GETPTIME_TIMEVAL(&net->cc_mod.rtcc.tls);
1507                 net->cc_mod.rtcc.tls_needs_set = 2;
1508         }
1509 }
1510
1511 static void
1512 sctp_cwnd_update_rtcc_after_sack(struct sctp_tcb *stcb,
1513     struct sctp_association *asoc,
1514     int accum_moved, int reneged_all, int will_exit)
1515 {
1516         /* Passing a one argument at the last enables the rtcc algorithm */
1517         sctp_cwnd_update_after_sack_common(stcb, asoc, accum_moved, reneged_all, will_exit, 1);
1518 }
1519
1520 static void
1521 sctp_rtt_rtcc_calculated(struct sctp_tcb *stcb SCTP_UNUSED,
1522     struct sctp_nets *net,
1523     struct timeval *now SCTP_UNUSED)
1524 {
1525         net->cc_mod.rtcc.rtt_set_this_sack = 1;
1526 }
1527
1528 /* Here starts Sally Floyds HS-TCP */
1529
1530 struct sctp_hs_raise_drop {
1531         int32_t cwnd;
1532         int8_t increase;
1533         int8_t drop_percent;
1534 };
1535
1536 #define SCTP_HS_TABLE_SIZE 73
1537
1538 static const struct sctp_hs_raise_drop sctp_cwnd_adjust[SCTP_HS_TABLE_SIZE] = {
1539         {38, 1, 50},            /* 0   */
1540         {118, 2, 44},           /* 1   */
1541         {221, 3, 41},           /* 2   */
1542         {347, 4, 38},           /* 3   */
1543         {495, 5, 37},           /* 4   */
1544         {663, 6, 35},           /* 5   */
1545         {851, 7, 34},           /* 6   */
1546         {1058, 8, 33},          /* 7   */
1547         {1284, 9, 32},          /* 8   */
1548         {1529, 10, 31},         /* 9   */
1549         {1793, 11, 30},         /* 10  */
1550         {2076, 12, 29},         /* 11  */
1551         {2378, 13, 28},         /* 12  */
1552         {2699, 14, 28},         /* 13  */
1553         {3039, 15, 27},         /* 14  */
1554         {3399, 16, 27},         /* 15  */
1555         {3778, 17, 26},         /* 16  */
1556         {4177, 18, 26},         /* 17  */
1557         {4596, 19, 25},         /* 18  */
1558         {5036, 20, 25},         /* 19  */
1559         {5497, 21, 24},         /* 20  */
1560         {5979, 22, 24},         /* 21  */
1561         {6483, 23, 23},         /* 22  */
1562         {7009, 24, 23},         /* 23  */
1563         {7558, 25, 22},         /* 24  */
1564         {8130, 26, 22},         /* 25  */
1565         {8726, 27, 22},         /* 26  */
1566         {9346, 28, 21},         /* 27  */
1567         {9991, 29, 21},         /* 28  */
1568         {10661, 30, 21},        /* 29  */
1569         {11358, 31, 20},        /* 30  */
1570         {12082, 32, 20},        /* 31  */
1571         {12834, 33, 20},        /* 32  */
1572         {13614, 34, 19},        /* 33  */
1573         {14424, 35, 19},        /* 34  */
1574         {15265, 36, 19},        /* 35  */
1575         {16137, 37, 19},        /* 36  */
1576         {17042, 38, 18},        /* 37  */
1577         {17981, 39, 18},        /* 38  */
1578         {18955, 40, 18},        /* 39  */
1579         {19965, 41, 17},        /* 40  */
1580         {21013, 42, 17},        /* 41  */
1581         {22101, 43, 17},        /* 42  */
1582         {23230, 44, 17},        /* 43  */
1583         {24402, 45, 16},        /* 44  */
1584         {25618, 46, 16},        /* 45  */
1585         {26881, 47, 16},        /* 46  */
1586         {28193, 48, 16},        /* 47  */
1587         {29557, 49, 15},        /* 48  */
1588         {30975, 50, 15},        /* 49  */
1589         {32450, 51, 15},        /* 50  */
1590         {33986, 52, 15},        /* 51  */
1591         {35586, 53, 14},        /* 52  */
1592         {37253, 54, 14},        /* 53  */
1593         {38992, 55, 14},        /* 54  */
1594         {40808, 56, 14},        /* 55  */
1595         {42707, 57, 13},        /* 56  */
1596         {44694, 58, 13},        /* 57  */
1597         {46776, 59, 13},        /* 58  */
1598         {48961, 60, 13},        /* 59  */
1599         {51258, 61, 13},        /* 60  */
1600         {53677, 62, 12},        /* 61  */
1601         {56230, 63, 12},        /* 62  */
1602         {58932, 64, 12},        /* 63  */
1603         {61799, 65, 12},        /* 64  */
1604         {64851, 66, 11},        /* 65  */
1605         {68113, 67, 11},        /* 66  */
1606         {71617, 68, 11},        /* 67  */
1607         {75401, 69, 10},        /* 68  */
1608         {79517, 70, 10},        /* 69  */
1609         {84035, 71, 10},        /* 70  */
1610         {89053, 72, 10},        /* 71  */
1611         {94717, 73, 9}          /* 72  */
1612 };
1613
1614 static void
1615 sctp_hs_cwnd_increase(struct sctp_tcb *stcb, struct sctp_nets *net)
1616 {
1617         int cur_val, i, indx, incr;
1618         int old_cwnd = net->cwnd;
1619
1620         cur_val = net->cwnd >> 10;
1621         indx = SCTP_HS_TABLE_SIZE - 1;
1622
1623         if (cur_val < sctp_cwnd_adjust[0].cwnd) {
1624                 /* normal mode */
1625                 if (net->net_ack > net->mtu) {
1626                         net->cwnd += net->mtu;
1627                 } else {
1628                         net->cwnd += net->net_ack;
1629                 }
1630         } else {
1631                 for (i = net->last_hs_used; i < SCTP_HS_TABLE_SIZE; i++) {
1632                         if (cur_val < sctp_cwnd_adjust[i].cwnd) {
1633                                 indx = i;
1634                                 break;
1635                         }
1636                 }
1637                 net->last_hs_used = indx;
1638                 incr = (((int32_t)sctp_cwnd_adjust[indx].increase) << 10);
1639                 net->cwnd += incr;
1640         }
1641         sctp_enforce_cwnd_limit(&stcb->asoc, net);
1642         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1643                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SS);
1644         }
1645 }
1646
1647 static void
1648 sctp_hs_cwnd_decrease(struct sctp_tcb *stcb, struct sctp_nets *net)
1649 {
1650         int cur_val, i, indx;
1651         int old_cwnd = net->cwnd;
1652
1653         cur_val = net->cwnd >> 10;
1654         if (cur_val < sctp_cwnd_adjust[0].cwnd) {
1655                 /* normal mode */
1656                 net->ssthresh = net->cwnd / 2;
1657                 if (net->ssthresh < (net->mtu * 2)) {
1658                         net->ssthresh = 2 * net->mtu;
1659                 }
1660                 net->cwnd = net->ssthresh;
1661         } else {
1662                 /* drop by the proper amount */
1663                 net->ssthresh = net->cwnd - (int)((net->cwnd / 100) *
1664                     (int32_t)sctp_cwnd_adjust[net->last_hs_used].drop_percent);
1665                 net->cwnd = net->ssthresh;
1666                 /* now where are we */
1667                 indx = net->last_hs_used;
1668                 cur_val = net->cwnd >> 10;
1669                 /* reset where we are in the table */
1670                 if (cur_val < sctp_cwnd_adjust[0].cwnd) {
1671                         /* feel out of hs */
1672                         net->last_hs_used = 0;
1673                 } else {
1674                         for (i = indx; i >= 1; i--) {
1675                                 if (cur_val > sctp_cwnd_adjust[i - 1].cwnd) {
1676                                         break;
1677                                 }
1678                         }
1679                         net->last_hs_used = indx;
1680                 }
1681         }
1682         sctp_enforce_cwnd_limit(&stcb->asoc, net);
1683         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1684                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_FR);
1685         }
1686 }
1687
1688 static void
1689 sctp_hs_cwnd_update_after_fr(struct sctp_tcb *stcb,
1690     struct sctp_association *asoc)
1691 {
1692         struct sctp_nets *net;
1693
1694         /*
1695          * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off > 0) &&
1696          * (net->fast_retran_loss_recovery == 0)))
1697          */
1698         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
1699                 if ((asoc->fast_retran_loss_recovery == 0) ||
1700                     (asoc->sctp_cmt_on_off > 0)) {
1701                         /* out of a RFC2582 Fast recovery window? */
1702                         if (net->net_ack > 0) {
1703                                 /*
1704                                  * per section 7.2.3, are there any
1705                                  * destinations that had a fast retransmit
1706                                  * to them. If so what we need to do is
1707                                  * adjust ssthresh and cwnd.
1708                                  */
1709                                 struct sctp_tmit_chunk *lchk;
1710
1711                                 sctp_hs_cwnd_decrease(stcb, net);
1712
1713                                 lchk = TAILQ_FIRST(&asoc->send_queue);
1714
1715                                 net->partial_bytes_acked = 0;
1716                                 /* Turn on fast recovery window */
1717                                 asoc->fast_retran_loss_recovery = 1;
1718                                 if (lchk == NULL) {
1719                                         /* Mark end of the window */
1720                                         asoc->fast_recovery_tsn = asoc->sending_seq - 1;
1721                                 } else {
1722                                         asoc->fast_recovery_tsn = lchk->rec.data.tsn - 1;
1723                                 }
1724
1725                                 /*
1726                                  * CMT fast recovery -- per destination
1727                                  * recovery variable.
1728                                  */
1729                                 net->fast_retran_loss_recovery = 1;
1730
1731                                 if (lchk == NULL) {
1732                                         /* Mark end of the window */
1733                                         net->fast_recovery_tsn = asoc->sending_seq - 1;
1734                                 } else {
1735                                         net->fast_recovery_tsn = lchk->rec.data.tsn - 1;
1736                                 }
1737
1738                                 sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
1739                                     stcb->sctp_ep, stcb, net,
1740                                     SCTP_FROM_SCTP_CC_FUNCTIONS + SCTP_LOC_2);
1741                                 sctp_timer_start(SCTP_TIMER_TYPE_SEND,
1742                                     stcb->sctp_ep, stcb, net);
1743                         }
1744                 } else if (net->net_ack > 0) {
1745                         /*
1746                          * Mark a peg that we WOULD have done a cwnd
1747                          * reduction but RFC2582 prevented this action.
1748                          */
1749                         SCTP_STAT_INCR(sctps_fastretransinrtt);
1750                 }
1751         }
1752 }
1753
1754 static void
1755 sctp_hs_cwnd_update_after_sack(struct sctp_tcb *stcb,
1756     struct sctp_association *asoc,
1757     int accum_moved, int reneged_all SCTP_UNUSED, int will_exit)
1758 {
1759         struct sctp_nets *net;
1760
1761         /******************************/
1762         /* update cwnd and Early FR   */
1763         /******************************/
1764         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
1765 #ifdef JANA_CMT_FAST_RECOVERY
1766                 /*
1767                  * CMT fast recovery code. Need to debug.
1768                  */
1769                 if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
1770                         if (SCTP_TSN_GE(asoc->last_acked_seq, net->fast_recovery_tsn) ||
1771                             SCTP_TSN_GE(net->pseudo_cumack, net->fast_recovery_tsn)) {
1772                                 net->will_exit_fast_recovery = 1;
1773                         }
1774                 }
1775 #endif
1776                 /* if nothing was acked on this destination skip it */
1777                 if (net->net_ack == 0) {
1778                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1779                                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
1780                         }
1781                         continue;
1782                 }
1783 #ifdef JANA_CMT_FAST_RECOVERY
1784                 /*
1785                  * CMT fast recovery code
1786                  */
1787                 /*
1788                  * if (sctp_cmt_on_off > 0 && net->fast_retran_loss_recovery
1789                  * && net->will_exit_fast_recovery == 0) { @@@ Do something
1790                  * } else if (sctp_cmt_on_off == 0 &&
1791                  * asoc->fast_retran_loss_recovery && will_exit == 0) {
1792                  */
1793 #endif
1794
1795                 if (asoc->fast_retran_loss_recovery &&
1796                     (will_exit == 0) &&
1797                     (asoc->sctp_cmt_on_off == 0)) {
1798                         /*
1799                          * If we are in loss recovery we skip any cwnd
1800                          * update
1801                          */
1802                         return;
1803                 }
1804                 /*
1805                  * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
1806                  * moved.
1807                  */
1808                 if (accum_moved ||
1809                     ((asoc->sctp_cmt_on_off > 0) && net->new_pseudo_cumack)) {
1810                         /* If the cumulative ack moved we can proceed */
1811                         if (net->cwnd <= net->ssthresh) {
1812                                 /* We are in slow start */
1813                                 if (net->flight_size + net->net_ack >= net->cwnd) {
1814                                         sctp_hs_cwnd_increase(stcb, net);
1815                                 } else {
1816                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1817                                                 sctp_log_cwnd(stcb, net, net->net_ack,
1818                                                     SCTP_CWND_LOG_NOADV_SS);
1819                                         }
1820                                 }
1821                         } else {
1822                                 /* We are in congestion avoidance */
1823                                 net->partial_bytes_acked += net->net_ack;
1824                                 if ((net->flight_size + net->net_ack >= net->cwnd) &&
1825                                     (net->partial_bytes_acked >= net->cwnd)) {
1826                                         net->partial_bytes_acked -= net->cwnd;
1827                                         net->cwnd += net->mtu;
1828                                         sctp_enforce_cwnd_limit(asoc, net);
1829                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1830                                                 sctp_log_cwnd(stcb, net, net->mtu,
1831                                                     SCTP_CWND_LOG_FROM_CA);
1832                                         }
1833                                 } else {
1834                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1835                                                 sctp_log_cwnd(stcb, net, net->net_ack,
1836                                                     SCTP_CWND_LOG_NOADV_CA);
1837                                         }
1838                                 }
1839                         }
1840                 } else {
1841                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1842                                 sctp_log_cwnd(stcb, net, net->mtu,
1843                                     SCTP_CWND_LOG_NO_CUMACK);
1844                         }
1845                 }
1846         }
1847 }
1848
1849 /*
1850  * H-TCP congestion control. The algorithm is detailed in:
1851  * R.N.Shorten, D.J.Leith:
1852  *   "H-TCP: TCP for high-speed and long-distance networks"
1853  *   Proc. PFLDnet, Argonne, 2004.
1854  * http://www.hamilton.ie/net/htcp3.pdf
1855  */
1856
1857 static int use_rtt_scaling = 1;
1858 static int use_bandwidth_switch = 1;
1859
1860 static inline int
1861 between(uint32_t seq1, uint32_t seq2, uint32_t seq3)
1862 {
1863         return (seq3 - seq2 >= seq1 - seq2);
1864 }
1865
1866 static inline uint32_t
1867 htcp_cong_time(struct htcp *ca)
1868 {
1869         return (sctp_get_tick_count() - ca->last_cong);
1870 }
1871
1872 static inline uint32_t
1873 htcp_ccount(struct htcp *ca)
1874 {
1875         return (ca->minRTT == 0 ? htcp_cong_time(ca) : htcp_cong_time(ca) / ca->minRTT);
1876 }
1877
1878 static inline void
1879 htcp_reset(struct htcp *ca)
1880 {
1881         ca->undo_last_cong = ca->last_cong;
1882         ca->undo_maxRTT = ca->maxRTT;
1883         ca->undo_old_maxB = ca->old_maxB;
1884         ca->last_cong = sctp_get_tick_count();
1885 }
1886
1887 #ifdef SCTP_NOT_USED
1888
1889 static uint32_t
1890 htcp_cwnd_undo(struct sctp_tcb *stcb, struct sctp_nets *net)
1891 {
1892         net->cc_mod.htcp_ca.last_cong = net->cc_mod.htcp_ca.undo_last_cong;
1893         net->cc_mod.htcp_ca.maxRTT = net->cc_mod.htcp_ca.undo_maxRTT;
1894         net->cc_mod.htcp_ca.old_maxB = net->cc_mod.htcp_ca.undo_old_maxB;
1895         return (max(net->cwnd, ((net->ssthresh / net->mtu << 7) / net->cc_mod.htcp_ca.beta) * net->mtu));
1896 }
1897
1898 #endif
1899
1900 static inline void
1901 measure_rtt(struct sctp_nets *net)
1902 {
1903         uint32_t srtt = net->lastsa >> SCTP_RTT_SHIFT;
1904
1905         /* keep track of minimum RTT seen so far, minRTT is zero at first */
1906         if (net->cc_mod.htcp_ca.minRTT > srtt || !net->cc_mod.htcp_ca.minRTT)
1907                 net->cc_mod.htcp_ca.minRTT = srtt;
1908
1909         /* max RTT */
1910         if (net->fast_retran_ip == 0 && net->ssthresh < 0xFFFF && htcp_ccount(&net->cc_mod.htcp_ca) > 3) {
1911                 if (net->cc_mod.htcp_ca.maxRTT < net->cc_mod.htcp_ca.minRTT)
1912                         net->cc_mod.htcp_ca.maxRTT = net->cc_mod.htcp_ca.minRTT;
1913                 if (net->cc_mod.htcp_ca.maxRTT < srtt && srtt <= net->cc_mod.htcp_ca.maxRTT + sctp_msecs_to_ticks(20))
1914                         net->cc_mod.htcp_ca.maxRTT = srtt;
1915         }
1916 }
1917
1918 static void
1919 measure_achieved_throughput(struct sctp_nets *net)
1920 {
1921         uint32_t now = sctp_get_tick_count();
1922
1923         if (net->fast_retran_ip == 0)
1924                 net->cc_mod.htcp_ca.bytes_acked = net->net_ack;
1925
1926         if (!use_bandwidth_switch)
1927                 return;
1928
1929         /* achieved throughput calculations */
1930         /* JRS - not 100% sure of this statement */
1931         if (net->fast_retran_ip == 1) {
1932                 net->cc_mod.htcp_ca.bytecount = 0;
1933                 net->cc_mod.htcp_ca.lasttime = now;
1934                 return;
1935         }
1936
1937         net->cc_mod.htcp_ca.bytecount += net->net_ack;
1938         if ((net->cc_mod.htcp_ca.bytecount >= net->cwnd - (((net->cc_mod.htcp_ca.alpha >> 7) ? (net->cc_mod.htcp_ca.alpha >> 7) : 1) * net->mtu)) &&
1939             (now - net->cc_mod.htcp_ca.lasttime >= net->cc_mod.htcp_ca.minRTT) &&
1940             (net->cc_mod.htcp_ca.minRTT > 0)) {
1941                 uint32_t cur_Bi = net->cc_mod.htcp_ca.bytecount / net->mtu * hz / (now - net->cc_mod.htcp_ca.lasttime);
1942
1943                 if (htcp_ccount(&net->cc_mod.htcp_ca) <= 3) {
1944                         /* just after backoff */
1945                         net->cc_mod.htcp_ca.minB = net->cc_mod.htcp_ca.maxB = net->cc_mod.htcp_ca.Bi = cur_Bi;
1946                 } else {
1947                         net->cc_mod.htcp_ca.Bi = (3 * net->cc_mod.htcp_ca.Bi + cur_Bi) / 4;
1948                         if (net->cc_mod.htcp_ca.Bi > net->cc_mod.htcp_ca.maxB)
1949                                 net->cc_mod.htcp_ca.maxB = net->cc_mod.htcp_ca.Bi;
1950                         if (net->cc_mod.htcp_ca.minB > net->cc_mod.htcp_ca.maxB)
1951                                 net->cc_mod.htcp_ca.minB = net->cc_mod.htcp_ca.maxB;
1952                 }
1953                 net->cc_mod.htcp_ca.bytecount = 0;
1954                 net->cc_mod.htcp_ca.lasttime = now;
1955         }
1956 }
1957
1958 static inline void
1959 htcp_beta_update(struct htcp *ca, uint32_t minRTT, uint32_t maxRTT)
1960 {
1961         if (use_bandwidth_switch) {
1962                 uint32_t maxB = ca->maxB;
1963                 uint32_t old_maxB = ca->old_maxB;
1964
1965                 ca->old_maxB = ca->maxB;
1966
1967                 if (!between(5 * maxB, 4 * old_maxB, 6 * old_maxB)) {
1968                         ca->beta = BETA_MIN;
1969                         ca->modeswitch = 0;
1970                         return;
1971                 }
1972         }
1973
1974         if (ca->modeswitch && minRTT > sctp_msecs_to_ticks(10) && maxRTT) {
1975                 ca->beta = (minRTT << 7) / maxRTT;
1976                 if (ca->beta < BETA_MIN)
1977                         ca->beta = BETA_MIN;
1978                 else if (ca->beta > BETA_MAX)
1979                         ca->beta = BETA_MAX;
1980         } else {
1981                 ca->beta = BETA_MIN;
1982                 ca->modeswitch = 1;
1983         }
1984 }
1985
1986 static inline void
1987 htcp_alpha_update(struct htcp *ca)
1988 {
1989         uint32_t minRTT = ca->minRTT;
1990         uint32_t factor = 1;
1991         uint32_t diff = htcp_cong_time(ca);
1992
1993         if (diff > (uint32_t)hz) {
1994                 diff -= hz;
1995                 factor = 1 + (10 * diff + ((diff / 2) * (diff / 2) / hz)) / hz;
1996         }
1997
1998         if (use_rtt_scaling && minRTT) {
1999                 uint32_t scale = (hz << 3) / (10 * minRTT);
2000
2001                 scale = min(max(scale, 1U << 2), 10U << 3);     /* clamping ratio to
2002                                                                  * interval [0.5,10]<<3 */
2003                 factor = (factor << 3) / scale;
2004                 if (factor != 0)
2005                         factor = 1;
2006         }
2007
2008         ca->alpha = 2 * factor * ((1 << 7) - ca->beta);
2009         if (ca->alpha != 0)
2010                 ca->alpha = ALPHA_BASE;
2011 }
2012
2013 /* After we have the rtt data to calculate beta, we'd still prefer to wait one
2014  * rtt before we adjust our beta to ensure we are working from a consistent
2015  * data.
2016  *
2017  * This function should be called when we hit a congestion event since only at
2018  * that point do we really have a real sense of maxRTT (the queues en route
2019  * were getting just too full now).
2020  */
2021 static void
2022 htcp_param_update(struct sctp_nets *net)
2023 {
2024         uint32_t minRTT = net->cc_mod.htcp_ca.minRTT;
2025         uint32_t maxRTT = net->cc_mod.htcp_ca.maxRTT;
2026
2027         htcp_beta_update(&net->cc_mod.htcp_ca, minRTT, maxRTT);
2028         htcp_alpha_update(&net->cc_mod.htcp_ca);
2029
2030         /*
2031          * add slowly fading memory for maxRTT to accommodate routing
2032          * changes etc
2033          */
2034         if (minRTT > 0 && maxRTT > minRTT)
2035                 net->cc_mod.htcp_ca.maxRTT = minRTT + ((maxRTT - minRTT) * 95) / 100;
2036 }
2037
2038 static uint32_t
2039 htcp_recalc_ssthresh(struct sctp_nets *net)
2040 {
2041         htcp_param_update(net);
2042         return (max(((net->cwnd / net->mtu * net->cc_mod.htcp_ca.beta) >> 7) * net->mtu, 2U * net->mtu));
2043 }
2044
2045 static void
2046 htcp_cong_avoid(struct sctp_tcb *stcb, struct sctp_nets *net)
2047 {
2048         /*-
2049          * How to handle these functions?
2050          *      if (!tcp_is_cwnd_limited(sk, in_flight)) RRS - good question.
2051          *              return;
2052          */
2053         if (net->cwnd <= net->ssthresh) {
2054                 /* We are in slow start */
2055                 if (net->flight_size + net->net_ack >= net->cwnd) {
2056                         if (net->net_ack > (net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable))) {
2057                                 net->cwnd += (net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable));
2058                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2059                                         sctp_log_cwnd(stcb, net, net->mtu,
2060                                             SCTP_CWND_LOG_FROM_SS);
2061                                 }
2062
2063                         } else {
2064                                 net->cwnd += net->net_ack;
2065                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2066                                         sctp_log_cwnd(stcb, net, net->net_ack,
2067                                             SCTP_CWND_LOG_FROM_SS);
2068                                 }
2069                         }
2070                         sctp_enforce_cwnd_limit(&stcb->asoc, net);
2071                 } else {
2072                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
2073                                 sctp_log_cwnd(stcb, net, net->net_ack,
2074                                     SCTP_CWND_LOG_NOADV_SS);
2075                         }
2076                 }
2077         } else {
2078                 measure_rtt(net);
2079
2080                 /*
2081                  * In dangerous area, increase slowly. In theory this is
2082                  * net->cwnd += alpha / net->cwnd
2083                  */
2084                 /* What is snd_cwnd_cnt?? */
2085                 if (((net->partial_bytes_acked / net->mtu * net->cc_mod.htcp_ca.alpha) >> 7) * net->mtu >= net->cwnd) {
2086                         /*-
2087                          * Does SCTP have a cwnd clamp?
2088                          * if (net->snd_cwnd < net->snd_cwnd_clamp) - Nope (RRS).
2089                          */
2090                         net->cwnd += net->mtu;
2091                         net->partial_bytes_acked = 0;
2092                         sctp_enforce_cwnd_limit(&stcb->asoc, net);
2093                         htcp_alpha_update(&net->cc_mod.htcp_ca);
2094                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2095                                 sctp_log_cwnd(stcb, net, net->mtu,
2096                                     SCTP_CWND_LOG_FROM_CA);
2097                         }
2098                 } else {
2099                         net->partial_bytes_acked += net->net_ack;
2100                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
2101                                 sctp_log_cwnd(stcb, net, net->net_ack,
2102                                     SCTP_CWND_LOG_NOADV_CA);
2103                         }
2104                 }
2105
2106                 net->cc_mod.htcp_ca.bytes_acked = net->mtu;
2107         }
2108 }
2109
2110 #ifdef SCTP_NOT_USED
2111 /* Lower bound on congestion window. */
2112 static uint32_t
2113 htcp_min_cwnd(struct sctp_tcb *stcb, struct sctp_nets *net)
2114 {
2115         return (net->ssthresh);
2116 }
2117 #endif
2118
2119 static void
2120 htcp_init(struct sctp_nets *net)
2121 {
2122         memset(&net->cc_mod.htcp_ca, 0, sizeof(struct htcp));
2123         net->cc_mod.htcp_ca.alpha = ALPHA_BASE;
2124         net->cc_mod.htcp_ca.beta = BETA_MIN;
2125         net->cc_mod.htcp_ca.bytes_acked = net->mtu;
2126         net->cc_mod.htcp_ca.last_cong = sctp_get_tick_count();
2127 }
2128
2129 static void
2130 sctp_htcp_set_initial_cc_param(struct sctp_tcb *stcb, struct sctp_nets *net)
2131 {
2132         /*
2133          * We take the max of the burst limit times a MTU or the
2134          * INITIAL_CWND. We then limit this to 4 MTU's of sending.
2135          */
2136         net->cwnd = min((net->mtu * 4), max((2 * net->mtu), SCTP_INITIAL_CWND));
2137         net->ssthresh = stcb->asoc.peers_rwnd;
2138         sctp_enforce_cwnd_limit(&stcb->asoc, net);
2139         htcp_init(net);
2140
2141         if (SCTP_BASE_SYSCTL(sctp_logging_level) & (SCTP_CWND_MONITOR_ENABLE | SCTP_CWND_LOGGING_ENABLE)) {
2142                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_INITIALIZATION);
2143         }
2144 }
2145
2146 static void
2147 sctp_htcp_cwnd_update_after_sack(struct sctp_tcb *stcb,
2148     struct sctp_association *asoc,
2149     int accum_moved, int reneged_all SCTP_UNUSED, int will_exit)
2150 {
2151         struct sctp_nets *net;
2152
2153         /******************************/
2154         /* update cwnd and Early FR   */
2155         /******************************/
2156         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
2157 #ifdef JANA_CMT_FAST_RECOVERY
2158                 /*
2159                  * CMT fast recovery code. Need to debug.
2160                  */
2161                 if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
2162                         if (SCTP_TSN_GE(asoc->last_acked_seq, net->fast_recovery_tsn) ||
2163                             SCTP_TSN_GE(net->pseudo_cumack, net->fast_recovery_tsn)) {
2164                                 net->will_exit_fast_recovery = 1;
2165                         }
2166                 }
2167 #endif
2168                 /* if nothing was acked on this destination skip it */
2169                 if (net->net_ack == 0) {
2170                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
2171                                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
2172                         }
2173                         continue;
2174                 }
2175 #ifdef JANA_CMT_FAST_RECOVERY
2176                 /*
2177                  * CMT fast recovery code
2178                  */
2179                 /*
2180                  * if (sctp_cmt_on_off > 0 && net->fast_retran_loss_recovery
2181                  * && net->will_exit_fast_recovery == 0) { @@@ Do something
2182                  * } else if (sctp_cmt_on_off == 0 &&
2183                  * asoc->fast_retran_loss_recovery && will_exit == 0) {
2184                  */
2185 #endif
2186
2187                 if (asoc->fast_retran_loss_recovery &&
2188                     will_exit == 0 &&
2189                     (asoc->sctp_cmt_on_off == 0)) {
2190                         /*
2191                          * If we are in loss recovery we skip any cwnd
2192                          * update
2193                          */
2194                         return;
2195                 }
2196                 /*
2197                  * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
2198                  * moved.
2199                  */
2200                 if (accum_moved ||
2201                     ((asoc->sctp_cmt_on_off > 0) && net->new_pseudo_cumack)) {
2202                         htcp_cong_avoid(stcb, net);
2203                         measure_achieved_throughput(net);
2204                 } else {
2205                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
2206                                 sctp_log_cwnd(stcb, net, net->mtu,
2207                                     SCTP_CWND_LOG_NO_CUMACK);
2208                         }
2209                 }
2210         }
2211 }
2212
2213 static void
2214 sctp_htcp_cwnd_update_after_fr(struct sctp_tcb *stcb,
2215     struct sctp_association *asoc)
2216 {
2217         struct sctp_nets *net;
2218
2219         /*
2220          * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off > 0) &&
2221          * (net->fast_retran_loss_recovery == 0)))
2222          */
2223         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
2224                 if ((asoc->fast_retran_loss_recovery == 0) ||
2225                     (asoc->sctp_cmt_on_off > 0)) {
2226                         /* out of a RFC2582 Fast recovery window? */
2227                         if (net->net_ack > 0) {
2228                                 /*
2229                                  * per section 7.2.3, are there any
2230                                  * destinations that had a fast retransmit
2231                                  * to them. If so what we need to do is
2232                                  * adjust ssthresh and cwnd.
2233                                  */
2234                                 struct sctp_tmit_chunk *lchk;
2235                                 int old_cwnd = net->cwnd;
2236
2237                                 /* JRS - reset as if state were changed */
2238                                 htcp_reset(&net->cc_mod.htcp_ca);
2239                                 net->ssthresh = htcp_recalc_ssthresh(net);
2240                                 net->cwnd = net->ssthresh;
2241                                 sctp_enforce_cwnd_limit(asoc, net);
2242                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2243                                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
2244                                             SCTP_CWND_LOG_FROM_FR);
2245                                 }
2246                                 lchk = TAILQ_FIRST(&asoc->send_queue);
2247
2248                                 net->partial_bytes_acked = 0;
2249                                 /* Turn on fast recovery window */
2250                                 asoc->fast_retran_loss_recovery = 1;
2251                                 if (lchk == NULL) {
2252                                         /* Mark end of the window */
2253                                         asoc->fast_recovery_tsn = asoc->sending_seq - 1;
2254                                 } else {
2255                                         asoc->fast_recovery_tsn = lchk->rec.data.tsn - 1;
2256                                 }
2257
2258                                 /*
2259                                  * CMT fast recovery -- per destination
2260                                  * recovery variable.
2261                                  */
2262                                 net->fast_retran_loss_recovery = 1;
2263
2264                                 if (lchk == NULL) {
2265                                         /* Mark end of the window */
2266                                         net->fast_recovery_tsn = asoc->sending_seq - 1;
2267                                 } else {
2268                                         net->fast_recovery_tsn = lchk->rec.data.tsn - 1;
2269                                 }
2270
2271                                 sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
2272                                     stcb->sctp_ep, stcb, net,
2273                                     SCTP_FROM_SCTP_CC_FUNCTIONS + SCTP_LOC_3);
2274                                 sctp_timer_start(SCTP_TIMER_TYPE_SEND,
2275                                     stcb->sctp_ep, stcb, net);
2276                         }
2277                 } else if (net->net_ack > 0) {
2278                         /*
2279                          * Mark a peg that we WOULD have done a cwnd
2280                          * reduction but RFC2582 prevented this action.
2281                          */
2282                         SCTP_STAT_INCR(sctps_fastretransinrtt);
2283                 }
2284         }
2285 }
2286
2287 static void
2288 sctp_htcp_cwnd_update_after_timeout(struct sctp_tcb *stcb,
2289     struct sctp_nets *net)
2290 {
2291         int old_cwnd = net->cwnd;
2292
2293         /* JRS - reset as if the state were being changed to timeout */
2294         htcp_reset(&net->cc_mod.htcp_ca);
2295         net->ssthresh = htcp_recalc_ssthresh(net);
2296         net->cwnd = net->mtu;
2297         net->partial_bytes_acked = 0;
2298         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2299                 sctp_log_cwnd(stcb, net, net->cwnd - old_cwnd, SCTP_CWND_LOG_FROM_RTX);
2300         }
2301 }
2302
2303 static void
2304 sctp_htcp_cwnd_update_after_ecn_echo(struct sctp_tcb *stcb,
2305     struct sctp_nets *net, int in_window, int num_pkt_lost SCTP_UNUSED)
2306 {
2307         int old_cwnd;
2308
2309         old_cwnd = net->cwnd;
2310
2311         /* JRS - reset hctp as if state changed */
2312         if (in_window == 0) {
2313                 htcp_reset(&net->cc_mod.htcp_ca);
2314                 SCTP_STAT_INCR(sctps_ecnereducedcwnd);
2315                 net->ssthresh = htcp_recalc_ssthresh(net);
2316                 if (net->ssthresh < net->mtu) {
2317                         net->ssthresh = net->mtu;
2318                         /* here back off the timer as well, to slow us down */
2319                         net->RTO <<= 1;
2320                 }
2321                 net->cwnd = net->ssthresh;
2322                 sctp_enforce_cwnd_limit(&stcb->asoc, net);
2323                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2324                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
2325                 }
2326         }
2327 }
2328
2329 const struct sctp_cc_functions sctp_cc_functions[] = {
2330         {
2331                 .sctp_set_initial_cc_param = sctp_set_initial_cc_param,
2332                 .sctp_cwnd_update_after_sack = sctp_cwnd_update_after_sack,
2333                 .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
2334                 .sctp_cwnd_update_after_fr = sctp_cwnd_update_after_fr,
2335                 .sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
2336                 .sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_after_ecn_echo,
2337                 .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
2338                 .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
2339         },
2340         {
2341                 .sctp_set_initial_cc_param = sctp_set_initial_cc_param,
2342                 .sctp_cwnd_update_after_sack = sctp_hs_cwnd_update_after_sack,
2343                 .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
2344                 .sctp_cwnd_update_after_fr = sctp_hs_cwnd_update_after_fr,
2345                 .sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
2346                 .sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_after_ecn_echo,
2347                 .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
2348                 .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
2349         },
2350         {
2351                 .sctp_set_initial_cc_param = sctp_htcp_set_initial_cc_param,
2352                 .sctp_cwnd_update_after_sack = sctp_htcp_cwnd_update_after_sack,
2353                 .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
2354                 .sctp_cwnd_update_after_fr = sctp_htcp_cwnd_update_after_fr,
2355                 .sctp_cwnd_update_after_timeout = sctp_htcp_cwnd_update_after_timeout,
2356                 .sctp_cwnd_update_after_ecn_echo = sctp_htcp_cwnd_update_after_ecn_echo,
2357                 .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
2358                 .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
2359         },
2360         {
2361                 .sctp_set_initial_cc_param = sctp_set_rtcc_initial_cc_param,
2362                 .sctp_cwnd_update_after_sack = sctp_cwnd_update_rtcc_after_sack,
2363                 .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
2364                 .sctp_cwnd_update_after_fr = sctp_cwnd_update_after_fr,
2365                 .sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
2366                 .sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_rtcc_after_ecn_echo,
2367                 .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
2368                 .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
2369                 .sctp_cwnd_update_packet_transmitted = sctp_cwnd_update_rtcc_packet_transmitted,
2370                 .sctp_cwnd_update_tsn_acknowledged = sctp_cwnd_update_rtcc_tsn_acknowledged,
2371                 .sctp_cwnd_new_transmission_begins = sctp_cwnd_new_rtcc_transmission_begins,
2372                 .sctp_cwnd_prepare_net_for_sack = sctp_cwnd_prepare_rtcc_net_for_sack,
2373                 .sctp_cwnd_socket_option = sctp_cwnd_rtcc_socket_option,
2374                 .sctp_rtt_calculated = sctp_rtt_rtcc_calculated
2375         }
2376 };