sys/netinet/sctp_cc_functions.c

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