sys/netinet/sctp_cc_functions.c

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