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