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_set_initial_cc_param(struct sctp_tcb *stcb, struct sctp_nets *net)
  57 {
  58         struct sctp_association *assoc;
  59         uint32_t cwnd_in_mtu;
  60
  61         assoc = &stcb->asoc;
  62         cwnd_in_mtu = SCTP_BASE_SYSCTL(sctp_initial_cwnd);
  63         if (cwnd_in_mtu == 0) {
  64                 /* Using 0 means that the value of RFC 4960 is used. */
  65                 net->cwnd = min((net->mtu * 4), max((2 * net->mtu), SCTP_INITIAL_CWND));
  66         } else {
  67                 /*
  68                  * We take the minimum of the burst limit and the initial
  69                  * congestion window.
  70                  */
  71                 if ((assoc->max_burst > 0) && (cwnd_in_mtu > assoc->max_burst))
  72                         cwnd_in_mtu = assoc->max_burst;
  73                 net->cwnd = (net->mtu - sizeof(struct sctphdr)) * cwnd_in_mtu;
  74         }
  75         if ((stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) ||
  76             (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV2)) {
  77                 /* In case of resource pooling initialize appropriately */
  78                 net->cwnd /= assoc->numnets;
  79                 if (net->cwnd < (net->mtu - sizeof(struct sctphdr))) {
  80                         net->cwnd = net->mtu - sizeof(struct sctphdr);
  81                 }
  82         }
  83         net->ssthresh = assoc->peers_rwnd;
  84         SDT_PROBE(sctp, cwnd, net, init,
  85             stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
  86             0, net->cwnd);
  87         if (SCTP_BASE_SYSCTL(sctp_logging_level) &
  88             (SCTP_CWND_MONITOR_ENABLE | SCTP_CWND_LOGGING_ENABLE)) {
  89                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_INITIALIZATION);
  90         }
  91 }
  92
  93 static void
  94 sctp_cwnd_update_after_fr(struct sctp_tcb *stcb,
  95     struct sctp_association *asoc)
  96 {
  97         struct sctp_nets *net;
  98         uint32_t t_ssthresh, t_cwnd;
  99         uint64_t t_ucwnd_sbw;
 100
 101         /* MT FIXME: Don't compute this over and over again */
 102         t_ssthresh = 0;
 103         t_cwnd = 0;
 104         t_ucwnd_sbw = 0;
 105         if ((asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) ||
 106             (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2)) {
 107                 TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
 108                         t_ssthresh += net->ssthresh;
 109                         t_cwnd += net->cwnd;
 110                         if (net->lastsa > 0) {
 111                                 t_ucwnd_sbw += (uint64_t) net->cwnd / (uint64_t) net->lastsa;
 112                         }
 113                 }
 114                 if (t_ucwnd_sbw == 0) {
 115                         t_ucwnd_sbw = 1;
 116                 }
 117         }
 118         /*-
 119          * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off > 0) &&
 120          * (net->fast_retran_loss_recovery == 0)))
 121          */
 122         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
 123                 if ((asoc->fast_retran_loss_recovery == 0) ||
 124                     (asoc->sctp_cmt_on_off > 0)) {
 125                         /* out of a RFC2582 Fast recovery window? */
 126                         if (net->net_ack > 0) {
 127                                 /*
 128                                  * per section 7.2.3, are there any
 129                                  * destinations that had a fast retransmit
 130                                  * to them. If so what we need to do is
 131                                  * adjust ssthresh and cwnd.
 132                                  */
 133                                 struct sctp_tmit_chunk *lchk;
 134                                 int old_cwnd = net->cwnd;
 135
 136                                 if ((asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) ||
 137                                     (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2)) {
 138                                         if (asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) {
 139                                                 net->ssthresh = (uint32_t) (((uint64_t) 4 *
 140                                                     (uint64_t) net->mtu *
 141                                                     (uint64_t) net->ssthresh) /
 142                                                     (uint64_t) t_ssthresh);
 143
 144                                         }
 145                                         if (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2) {
 146                                                 uint32_t srtt;
 147
 148                                                 srtt = net->lastsa;
 149                                                 /*
 150                                                  * lastsa>>3;  we don't need
 151                                                  * to devide ...
 152                                                  */
 153                                                 if (srtt == 0) {
 154                                                         srtt = 1;
 155                                                 }
 156                                                 /*
 157                                                  * Short Version => Equal to
 158                                                  * Contel Version MBe
 159                                                  */
 160                                                 net->ssthresh = (uint32_t) (((uint64_t) 4 *
 161                                                     (uint64_t) net->mtu *
 162                                                     (uint64_t) net->cwnd) /
 163                                                     ((uint64_t) srtt *
 164                                                     t_ucwnd_sbw));
 165                                                  /* INCREASE FACTOR */ ;
 166                                         }
 167                                         if ((net->cwnd > t_cwnd / 2) &&
 168                                             (net->ssthresh < net->cwnd - t_cwnd / 2)) {
 169                                                 net->ssthresh = net->cwnd - t_cwnd / 2;
 170                                         }
 171                                         if (net->ssthresh < net->mtu) {
 172                                                 net->ssthresh = net->mtu;
 173                                         }
 174                                 } else {
 175                                         net->ssthresh = net->cwnd / 2;
 176                                         if (net->ssthresh < (net->mtu * 2)) {
 177                                                 net->ssthresh = 2 * net->mtu;
 178                                         }
 179                                 }
 180                                 net->cwnd = net->ssthresh;
 181                                 SDT_PROBE(sctp, cwnd, net, fr,
 182                                     stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
 183                                     old_cwnd, net->cwnd);
 184                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 185                                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
 186                                             SCTP_CWND_LOG_FROM_FR);
 187                                 }
 188                                 lchk = TAILQ_FIRST(&asoc->send_queue);
 189
 190                                 net->partial_bytes_acked = 0;
 191                                 /* Turn on fast recovery window */
 192                                 asoc->fast_retran_loss_recovery = 1;
 193                                 if (lchk == NULL) {
 194                                         /* Mark end of the window */
 195                                         asoc->fast_recovery_tsn = asoc->sending_seq - 1;
 196                                 } else {
 197                                         asoc->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
 198                                 }
 199
 200                                 /*
 201                                  * CMT fast recovery -- per destination
 202                                  * recovery variable.
 203                                  */
 204                                 net->fast_retran_loss_recovery = 1;
 205
 206                                 if (lchk == NULL) {
 207                                         /* Mark end of the window */
 208                                         net->fast_recovery_tsn = asoc->sending_seq - 1;
 209                                 } else {
 210                                         net->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
 211                                 }
 212
 213                                 sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
 214                                     stcb->sctp_ep, stcb, net, SCTP_FROM_SCTP_INDATA + SCTP_LOC_32);
 215                                 sctp_timer_start(SCTP_TIMER_TYPE_SEND,
 216                                     stcb->sctp_ep, stcb, net);
 217                         }
 218                 } else if (net->net_ack > 0) {
 219                         /*
 220                          * Mark a peg that we WOULD have done a cwnd
 221                          * reduction but RFC2582 prevented this action.
 222                          */
 223                         SCTP_STAT_INCR(sctps_fastretransinrtt);
 224                 }
 225         }
 226 }
 227
 228 /* Defines for instantaneous bw decisions */
 229 #define SCTP_INST_LOOSING 1     /* Loosing to other flows */
 230 #define SCTP_INST_NEUTRAL 2     /* Neutral, no indication */
 231 #define SCTP_INST_GAINING 3     /* Gaining, step down possible */
 232
 233
 234 static int
 235 cc_bw_same(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw,
 236     uint64_t rtt_offset, uint64_t vtag, uint8_t inst_ind)
 237 {
 238         uint64_t oth, probepoint;
 239
 240         probepoint = (((uint64_t) net->cwnd) << 32);
 241         if (net->rtt > net->cc_mod.rtcc.lbw_rtt + rtt_offset) {
 242                 /*
 243                  * rtt increased we don't update bw.. so we don't update the
 244                  * rtt either.
 245                  */
 246                 /* Probe point 5 */
 247                 probepoint |= ((5 << 16) | 1);
 248                 SDT_PROBE(sctp, cwnd, net, rttvar,
 249                     vtag,
 250                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 251                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 252                     net->flight_size,
 253                     probepoint);
 254                 if ((net->cc_mod.rtcc.steady_step) && (inst_ind != SCTP_INST_LOOSING)) {
 255                         if (net->cc_mod.rtcc.last_step_state == 5)
 256                                 net->cc_mod.rtcc.step_cnt++;
 257                         else
 258                                 net->cc_mod.rtcc.step_cnt = 1;
 259                         net->cc_mod.rtcc.last_step_state = 5;
 260                         if ((net->cc_mod.rtcc.step_cnt == net->cc_mod.rtcc.steady_step) ||
 261                             ((net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step) &&
 262                             ((net->cc_mod.rtcc.step_cnt % net->cc_mod.rtcc.steady_step) == 0))) {
 263                                 /* Try a step down */
 264                                 oth = net->cc_mod.rtcc.vol_reduce;
 265                                 oth <<= 16;
 266                                 oth |= net->cc_mod.rtcc.step_cnt;
 267                                 oth <<= 16;
 268                                 oth |= net->cc_mod.rtcc.last_step_state;
 269                                 SDT_PROBE(sctp, cwnd, net, rttstep,
 270                                     vtag,
 271                                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 272                                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 273                                     oth,
 274                                     probepoint);
 275                                 if (net->cwnd > (4 * net->mtu)) {
 276                                         net->cwnd -= net->mtu;
 277                                         net->cc_mod.rtcc.vol_reduce++;
 278                                 } else {
 279                                         net->cc_mod.rtcc.step_cnt = 0;
 280                                 }
 281                         }
 282                 }
 283                 return (1);
 284         }
 285         if (net->rtt < net->cc_mod.rtcc.lbw_rtt - rtt_offset) {
 286                 /*
 287                  * rtt decreased, there could be more room. we update both
 288                  * the bw and the rtt here to lock this in as a good step
 289                  * down.
 290                  */
 291                 /* Probe point 6 */
 292                 probepoint |= ((6 << 16) | 0);
 293                 SDT_PROBE(sctp, cwnd, net, rttvar,
 294                     vtag,
 295                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 296                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 297                     net->flight_size,
 298                     probepoint);
 299                 if (net->cc_mod.rtcc.steady_step) {
 300                         oth = net->cc_mod.rtcc.vol_reduce;
 301                         oth <<= 16;
 302                         oth |= net->cc_mod.rtcc.step_cnt;
 303                         oth <<= 16;
 304                         oth |= net->cc_mod.rtcc.last_step_state;
 305                         SDT_PROBE(sctp, cwnd, net, rttstep,
 306                             vtag,
 307                             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 308                             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 309                             oth,
 310                             probepoint);
 311                         if ((net->cc_mod.rtcc.last_step_state == 5) &&
 312                             (net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step)) {
 313                                 /* Step down worked */
 314                                 net->cc_mod.rtcc.step_cnt = 0;
 315                                 return (1);
 316                         } else {
 317                                 net->cc_mod.rtcc.last_step_state = 6;
 318                                 net->cc_mod.rtcc.step_cnt = 0;
 319                         }
 320                 }
 321                 net->cc_mod.rtcc.lbw = nbw;
 322                 net->cc_mod.rtcc.lbw_rtt = net->rtt;
 323                 net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
 324                 if (inst_ind == SCTP_INST_GAINING)
 325                         return (1);
 326                 else if (inst_ind == SCTP_INST_NEUTRAL)
 327                         return (1);
 328                 else
 329                         return (0);
 330         }
 331         /*
 332          * Ok bw and rtt remained the same .. no update to any
 333          */
 334         /* Probe point 7 */
 335         probepoint |= ((7 << 16) | net->cc_mod.rtcc.ret_from_eq);
 336         SDT_PROBE(sctp, cwnd, net, rttvar,
 337             vtag,
 338             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 339             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 340             net->flight_size,
 341             probepoint);
 342         if ((net->cc_mod.rtcc.steady_step) && (inst_ind != SCTP_INST_LOOSING)) {
 343                 if (net->cc_mod.rtcc.last_step_state == 5)
 344                         net->cc_mod.rtcc.step_cnt++;
 345                 else
 346                         net->cc_mod.rtcc.step_cnt = 1;
 347                 net->cc_mod.rtcc.last_step_state = 5;
 348                 if ((net->cc_mod.rtcc.step_cnt == net->cc_mod.rtcc.steady_step) ||
 349                     ((net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step) &&
 350                     ((net->cc_mod.rtcc.step_cnt % net->cc_mod.rtcc.steady_step) == 0))) {
 351                         /* Try a step down */
 352                         if (net->cwnd > (4 * net->mtu)) {
 353                                 net->cwnd -= net->mtu;
 354                                 net->cc_mod.rtcc.vol_reduce++;
 355                                 return (1);
 356                         } else {
 357                                 net->cc_mod.rtcc.step_cnt = 0;
 358                         }
 359                 }
 360         }
 361         if (inst_ind == SCTP_INST_GAINING)
 362                 return (1);
 363         else if (inst_ind == SCTP_INST_NEUTRAL)
 364                 return (1);
 365         else
 366                 return ((int)net->cc_mod.rtcc.ret_from_eq);
 367 }
 368
 369 static int
 370 cc_bw_decrease(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw, uint64_t rtt_offset,
 371     uint64_t vtag, uint8_t inst_ind)
 372 {
 373         uint64_t oth, probepoint;
 374
 375         /* Bandwidth decreased. */
 376         probepoint = (((uint64_t) net->cwnd) << 32);
 377         if (net->rtt > net->cc_mod.rtcc.lbw_rtt + rtt_offset) {
 378                 /* rtt increased */
 379                 /* Did we add more */
 380                 if ((net->cwnd > net->cc_mod.rtcc.cwnd_at_bw_set) &&
 381                     (inst_ind != SCTP_INST_LOOSING)) {
 382                         /* We caused it maybe.. back off? */
 383                         /* PROBE POINT 1 */
 384                         probepoint |= ((1 << 16) | 1);
 385                         SDT_PROBE(sctp, cwnd, net, rttvar,
 386                             vtag,
 387                             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 388                             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 389                             net->flight_size,
 390                             probepoint);
 391                         if (net->cc_mod.rtcc.ret_from_eq) {
 392                                 /*
 393                                  * Switch over to CA if we are less
 394                                  * aggressive
 395                                  */
 396                                 net->ssthresh = net->cwnd - 1;
 397                                 net->partial_bytes_acked = 0;
 398                         }
 399                         return (1);
 400                 }
 401                 /* Probe point 2 */
 402                 probepoint |= ((2 << 16) | 0);
 403                 SDT_PROBE(sctp, cwnd, net, rttvar,
 404                     vtag,
 405                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 406                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 407                     net->flight_size,
 408                     probepoint);
 409                 /* Someone else - fight for more? */
 410                 if (net->cc_mod.rtcc.steady_step) {
 411                         oth = net->cc_mod.rtcc.vol_reduce;
 412                         oth <<= 16;
 413                         oth |= net->cc_mod.rtcc.step_cnt;
 414                         oth <<= 16;
 415                         oth |= net->cc_mod.rtcc.last_step_state;
 416                         SDT_PROBE(sctp, cwnd, net, rttstep,
 417                             vtag,
 418                             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 419                             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 420                             oth,
 421                             probepoint);
 422                         /*
 423                          * Did we voluntarily give up some? if so take one
 424                          * back please
 425                          */
 426                         if ((net->cc_mod.rtcc.vol_reduce) &&
 427                             (inst_ind != SCTP_INST_GAINING)) {
 428                                 net->cwnd += net->mtu;
 429                                 net->cc_mod.rtcc.vol_reduce--;
 430                         }
 431                         net->cc_mod.rtcc.last_step_state = 2;
 432                         net->cc_mod.rtcc.step_cnt = 0;
 433                 }
 434                 goto out_decision;
 435         } else if (net->rtt < net->cc_mod.rtcc.lbw_rtt - rtt_offset) {
 436                 /* bw & rtt decreased */
 437                 /* Probe point 3 */
 438                 probepoint |= ((3 << 16) | 0);
 439                 SDT_PROBE(sctp, cwnd, net, rttvar,
 440                     vtag,
 441                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 442                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 443                     net->flight_size,
 444                     probepoint);
 445                 if (net->cc_mod.rtcc.steady_step) {
 446                         oth = net->cc_mod.rtcc.vol_reduce;
 447                         oth <<= 16;
 448                         oth |= net->cc_mod.rtcc.step_cnt;
 449                         oth <<= 16;
 450                         oth |= net->cc_mod.rtcc.last_step_state;
 451                         SDT_PROBE(sctp, cwnd, net, rttstep,
 452                             vtag,
 453                             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 454                             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 455                             oth,
 456                             probepoint);
 457                         if ((net->cc_mod.rtcc.vol_reduce) &&
 458                             (inst_ind != SCTP_INST_GAINING)) {
 459                                 net->cwnd += net->mtu;
 460                                 net->cc_mod.rtcc.vol_reduce--;
 461                         }
 462                         net->cc_mod.rtcc.last_step_state = 3;
 463                         net->cc_mod.rtcc.step_cnt = 0;
 464                 }
 465                 goto out_decision;
 466         }
 467         /* The bw decreased but rtt stayed the same */
 468         /* Probe point 4 */
 469         probepoint |= ((4 << 16) | 0);
 470         SDT_PROBE(sctp, cwnd, net, rttvar,
 471             vtag,
 472             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 473             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 474             net->flight_size,
 475             probepoint);
 476         if (net->cc_mod.rtcc.steady_step) {
 477                 oth = net->cc_mod.rtcc.vol_reduce;
 478                 oth <<= 16;
 479                 oth |= net->cc_mod.rtcc.step_cnt;
 480                 oth <<= 16;
 481                 oth |= net->cc_mod.rtcc.last_step_state;
 482                 SDT_PROBE(sctp, cwnd, net, rttstep,
 483                     vtag,
 484                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 485                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 486                     oth,
 487                     probepoint);
 488                 if ((net->cc_mod.rtcc.vol_reduce) &&
 489                     (inst_ind != SCTP_INST_GAINING)) {
 490                         net->cwnd += net->mtu;
 491                         net->cc_mod.rtcc.vol_reduce--;
 492                 }
 493                 net->cc_mod.rtcc.last_step_state = 4;
 494                 net->cc_mod.rtcc.step_cnt = 0;
 495         }
 496 out_decision:
 497         net->cc_mod.rtcc.lbw = nbw;
 498         net->cc_mod.rtcc.lbw_rtt = net->rtt;
 499         net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
 500         if (inst_ind == SCTP_INST_GAINING) {
 501                 return (1);
 502         } else {
 503                 return (0);
 504         }
 505 }
 506
 507 static int
 508 cc_bw_increase(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw, uint64_t vtag)
 509 {
 510         uint64_t oth, probepoint;
 511
 512         /*
 513          * BW increased, so update and return 0, since all actions in our
 514          * table say to do the normal CC update. Note that we pay no
 515          * attention to the inst_ind since our overall sum is increasing.
 516          */
 517         /* PROBE POINT 0 */
 518         probepoint = (((uint64_t) net->cwnd) << 32);
 519         SDT_PROBE(sctp, cwnd, net, rttvar,
 520             vtag,
 521             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 522             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 523             net->flight_size,
 524             probepoint);
 525         if (net->cc_mod.rtcc.steady_step) {
 526                 oth = net->cc_mod.rtcc.vol_reduce;
 527                 oth <<= 16;
 528                 oth |= net->cc_mod.rtcc.step_cnt;
 529                 oth <<= 16;
 530                 oth |= net->cc_mod.rtcc.last_step_state;
 531                 SDT_PROBE(sctp, cwnd, net, rttstep,
 532                     vtag,
 533                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 534                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 535                     oth,
 536                     probepoint);
 537                 net->cc_mod.rtcc.last_step_state = 0;
 538                 net->cc_mod.rtcc.step_cnt = 0;
 539                 net->cc_mod.rtcc.vol_reduce = 0;
 540         }
 541         net->cc_mod.rtcc.lbw = nbw;
 542         net->cc_mod.rtcc.lbw_rtt = net->rtt;
 543         net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
 544         return (0);
 545 }
 546
 547 /* RTCC Algoritm to limit growth of cwnd, return
 548  * true if you want to NOT allow cwnd growth
 549  */
 550 static int
 551 cc_bw_limit(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw)
 552 {
 553         uint64_t bw_offset, rtt_offset;
 554         uint64_t probepoint, rtt, vtag;
 555         uint64_t bytes_for_this_rtt, inst_bw;
 556         uint64_t div, inst_off;
 557         int bw_shift;
 558         uint8_t inst_ind;
 559         int ret;
 560
 561         /*-
 562          * Here we need to see if we want
 563          * to limit cwnd growth due to increase
 564          * in overall rtt but no increase in bw.
 565          * We use the following table to figure
 566          * out what we should do. When we return
 567          * 0, cc update goes on as planned. If we
 568          * return 1, then no cc update happens and cwnd
 569          * stays where it is at.
 570          * ----------------------------------
 571          *   BW    |    RTT   | Action
 572          * *********************************
 573          *   INC   |    INC   | return 0
 574          * ----------------------------------
 575          *   INC   |    SAME  | return 0
 576          * ----------------------------------
 577          *   INC   |    DECR  | return 0
 578          * ----------------------------------
 579          *   SAME  |    INC   | return 1
 580          * ----------------------------------
 581          *   SAME  |    SAME  | return 1
 582          * ----------------------------------
 583          *   SAME  |    DECR  | return 0
 584          * ----------------------------------
 585          *   DECR  |    INC   | return 0 or 1 based on if we caused.
 586          * ----------------------------------
 587          *   DECR  |    SAME  | return 0
 588          * ----------------------------------
 589          *   DECR  |    DECR  | return 0
 590          * ----------------------------------
 591          *
 592          * We are a bit fuzz on what an increase or
 593          * decrease is. For BW it is the same if
 594          * it did not change within 1/64th. For
 595          * RTT it stayed the same if it did not
 596          * change within 1/32nd
 597          */
 598         bw_shift = SCTP_BASE_SYSCTL(sctp_rttvar_bw);
 599         rtt = stcb->asoc.my_vtag;
 600         vtag = (rtt << 32) | (((uint32_t) (stcb->sctp_ep->sctp_lport)) << 16) | (stcb->rport);
 601         probepoint = (((uint64_t) net->cwnd) << 32);
 602         rtt = net->rtt;
 603         if (net->cc_mod.rtcc.rtt_set_this_sack) {
 604                 net->cc_mod.rtcc.rtt_set_this_sack = 0;
 605                 bytes_for_this_rtt = net->cc_mod.rtcc.bw_bytes - net->cc_mod.rtcc.bw_bytes_at_last_rttc;
 606                 net->cc_mod.rtcc.bw_bytes_at_last_rttc = net->cc_mod.rtcc.bw_bytes;
 607                 if (net->rtt) {
 608                         div = net->rtt / 1000;
 609                         if (div) {
 610                                 inst_bw = bytes_for_this_rtt / div;
 611                                 inst_off = inst_bw >> bw_shift;
 612                                 if (inst_bw > nbw)
 613                                         inst_ind = SCTP_INST_GAINING;
 614                                 else if ((inst_bw + inst_off) < nbw)
 615                                         inst_ind = SCTP_INST_LOOSING;
 616                                 else
 617                                         inst_ind = SCTP_INST_NEUTRAL;
 618                                 probepoint |= ((0xb << 16) | inst_ind);
 619                         } else {
 620                                 inst_ind = net->cc_mod.rtcc.last_inst_ind;
 621                                 inst_bw = bytes_for_this_rtt / (uint64_t) (net->rtt);
 622                                 /* Can't determine do not change */
 623                                 probepoint |= ((0xc << 16) | inst_ind);
 624                         }
 625                 } else {
 626                         inst_ind = net->cc_mod.rtcc.last_inst_ind;
 627                         inst_bw = bytes_for_this_rtt;
 628                         /* Can't determine do not change */
 629                         probepoint |= ((0xd << 16) | inst_ind);
 630                 }
 631                 SDT_PROBE(sctp, cwnd, net, rttvar,
 632                     vtag,
 633                     ((nbw << 32) | inst_bw),
 634                     ((net->cc_mod.rtcc.lbw_rtt << 32) | rtt),
 635                     net->flight_size,
 636                     probepoint);
 637         } else {
 638                 /* No rtt measurement, use last one */
 639                 inst_ind = net->cc_mod.rtcc.last_inst_ind;
 640         }
 641         bw_offset = net->cc_mod.rtcc.lbw >> bw_shift;
 642         if (nbw > net->cc_mod.rtcc.lbw + bw_offset) {
 643                 ret = cc_bw_increase(stcb, net, nbw, vtag);
 644                 goto out;
 645         }
 646         rtt_offset = net->cc_mod.rtcc.lbw_rtt >> SCTP_BASE_SYSCTL(sctp_rttvar_rtt);
 647         if (nbw < net->cc_mod.rtcc.lbw - bw_offset) {
 648                 ret = cc_bw_decrease(stcb, net, nbw, rtt_offset, vtag, inst_ind);
 649                 goto out;
 650         }
 651         /*
 652          * If we reach here then we are in a situation where the bw stayed
 653          * the same.
 654          */
 655         ret = cc_bw_same(stcb, net, nbw, rtt_offset, vtag, inst_ind);
 656 out:
 657         net->cc_mod.rtcc.last_inst_ind = inst_ind;
 658         return (ret);
 659 }
 660
 661 static void
 662 sctp_cwnd_update_after_sack_common(struct sctp_tcb *stcb,
 663     struct sctp_association *asoc,
 664     int accum_moved, int reneged_all SCTP_UNUSED, int will_exit, int use_rtcc)
 665 {
 666         struct sctp_nets *net;
 667         int old_cwnd;
 668         uint32_t t_ssthresh, t_cwnd, incr;
 669         uint64_t t_ucwnd_sbw;
 670         uint64_t t_path_mptcp;
 671         uint64_t mptcp_like_alpha;
 672         uint32_t srtt;
 673         uint64_t max_path;
 674
 675         /* MT FIXME: Don't compute this over and over again */
 676         t_ssthresh = 0;
 677         t_cwnd = 0;
 678         t_ucwnd_sbw = 0;
 679         t_path_mptcp = 0;
 680         mptcp_like_alpha = 1;
 681         if ((stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) ||
 682             (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV2) ||
 683             (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_MPTCP)) {
 684                 max_path = 0;
 685                 TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
 686                         t_ssthresh += net->ssthresh;
 687                         t_cwnd += net->cwnd;
 688                         /* lastsa>>3;  we don't need to devide ... */
 689                         srtt = net->lastsa;
 690                         if (srtt > 0) {
 691                                 uint64_t tmp;
 692
 693                                 t_ucwnd_sbw += (uint64_t) net->cwnd / (uint64_t) srtt;
 694                                 t_path_mptcp += (((uint64_t) net->cwnd) << SHIFT_MPTCP_MULTI_Z) /
 695                                     (((uint64_t) net->mtu) * (uint64_t) srtt);
 696                                 tmp = (((uint64_t) net->cwnd) << SHIFT_MPTCP_MULTI_N) /
 697                                     ((uint64_t) net->mtu * (uint64_t) (srtt * srtt));
 698                                 if (tmp > max_path) {
 699                                         max_path = tmp;
 700                                 }
 701                         }
 702                 }
 703                 if (t_path_mptcp > 0) {
 704                         mptcp_like_alpha = max_path / (t_path_mptcp * t_path_mptcp);
 705                 } else {
 706                         mptcp_like_alpha = 1;
 707                 }
 708         }
 709         if (t_ssthresh == 0) {
 710                 t_ssthresh = 1;
 711         }
 712         if (t_ucwnd_sbw == 0) {
 713                 t_ucwnd_sbw = 1;
 714         }
 715         /******************************/
 716         /* update cwnd and Early FR   */
 717         /******************************/
 718         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
 719
 720 #ifdef JANA_CMT_FAST_RECOVERY
 721                 /*
 722                  * CMT fast recovery code. Need to debug.
 723                  */
 724                 if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
 725                         if (SCTP_TSN_GE(asoc->last_acked_seq, net->fast_recovery_tsn) ||
 726                             SCTP_TSN_GE(net->pseudo_cumack, net->fast_recovery_tsn)) {
 727                                 net->will_exit_fast_recovery = 1;
 728                         }
 729                 }
 730 #endif
 731                 /* if nothing was acked on this destination skip it */
 732                 if (net->net_ack == 0) {
 733                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 734                                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
 735                         }
 736                         continue;
 737                 }
 738 #ifdef JANA_CMT_FAST_RECOVERY
 739                 /*
 740                  * CMT fast recovery code
 741                  */
 742                 /*
 743                  * if (sctp_cmt_on_off > 0 && net->fast_retran_loss_recovery
 744                  * && net->will_exit_fast_recovery == 0) { @@@ Do something
 745                  * } else if (sctp_cmt_on_off == 0 &&
 746                  * asoc->fast_retran_loss_recovery && will_exit == 0) {
 747                  */
 748 #endif
 749
 750                 if (asoc->fast_retran_loss_recovery &&
 751                     (will_exit == 0) &&
 752                     (asoc->sctp_cmt_on_off == 0)) {
 753                         /*
 754                          * If we are in loss recovery we skip any cwnd
 755                          * update
 756                          */
 757                         return;
 758                 }
 759                 /*
 760                  * Did any measurements go on for this network?
 761                  */
 762                 if (use_rtcc && (net->cc_mod.rtcc.tls_needs_set > 0)) {
 763                         uint64_t nbw;
 764
 765                         /*
 766                          * At this point our bw_bytes has been updated by
 767                          * incoming sack information.
 768                          *
 769                          * But our bw may not yet be set.
 770                          *
 771                          */
 772                         if ((net->cc_mod.rtcc.new_tot_time / 1000) > 0) {
 773                                 nbw = net->cc_mod.rtcc.bw_bytes / (net->cc_mod.rtcc.new_tot_time / 1000);
 774                         } else {
 775                                 nbw = net->cc_mod.rtcc.bw_bytes;
 776                         }
 777                         if (net->cc_mod.rtcc.lbw) {
 778                                 if (cc_bw_limit(stcb, net, nbw)) {
 779                                         /* Hold here, no update */
 780                                         continue;
 781                                 }
 782                         } else {
 783                                 uint64_t vtag, probepoint;
 784
 785                                 probepoint = (((uint64_t) net->cwnd) << 32);
 786                                 probepoint |= ((0xa << 16) | 0);
 787                                 vtag = (net->rtt << 32) |
 788                                     (((uint32_t) (stcb->sctp_ep->sctp_lport)) << 16) |
 789                                     (stcb->rport);
 790
 791                                 SDT_PROBE(sctp, cwnd, net, rttvar,
 792                                     vtag,
 793                                     nbw,
 794                                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 795                                     net->flight_size,
 796                                     probepoint);
 797                                 net->cc_mod.rtcc.lbw = nbw;
 798                                 net->cc_mod.rtcc.lbw_rtt = net->rtt;
 799                                 if (net->cc_mod.rtcc.rtt_set_this_sack) {
 800                                         net->cc_mod.rtcc.rtt_set_this_sack = 0;
 801                                         net->cc_mod.rtcc.bw_bytes_at_last_rttc = net->cc_mod.rtcc.bw_bytes;
 802                                 }
 803                         }
 804                 }
 805                 /*
 806                  * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
 807                  * moved.
 808                  */
 809                 if (accum_moved ||
 810                     ((asoc->sctp_cmt_on_off > 0) && net->new_pseudo_cumack)) {
 811                         /* If the cumulative ack moved we can proceed */
 812                         if (net->cwnd <= net->ssthresh) {
 813                                 /* We are in slow start */
 814                                 if (net->flight_size + net->net_ack >= net->cwnd) {
 815                                         uint32_t limit;
 816
 817                                         old_cwnd = net->cwnd;
 818                                         switch (asoc->sctp_cmt_on_off) {
 819                                         case SCTP_CMT_RPV1:
 820                                                 limit = (uint32_t) (((uint64_t) net->mtu *
 821                                                     (uint64_t) SCTP_BASE_SYSCTL(sctp_L2_abc_variable) *
 822                                                     (uint64_t) net->ssthresh) /
 823                                                     (uint64_t) t_ssthresh);
 824                                                 incr = (uint32_t) (((uint64_t) net->net_ack *
 825                                                     (uint64_t) net->ssthresh) /
 826                                                     (uint64_t) t_ssthresh);
 827                                                 if (incr > limit) {
 828                                                         incr = limit;
 829                                                 }
 830                                                 if (incr == 0) {
 831                                                         incr = 1;
 832                                                 }
 833                                                 break;
 834                                         case SCTP_CMT_RPV2:
 835                                                 /*
 836                                                  * lastsa>>3;  we don't need
 837                                                  * to divide ...
 838                                                  */
 839                                                 srtt = net->lastsa;
 840                                                 if (srtt == 0) {
 841                                                         srtt = 1;
 842                                                 }
 843                                                 limit = (uint32_t) (((uint64_t) net->mtu *
 844                                                     (uint64_t) SCTP_BASE_SYSCTL(sctp_L2_abc_variable) *
 845                                                     (uint64_t) net->cwnd) /
 846                                                     ((uint64_t) srtt * t_ucwnd_sbw));
 847                                                 /* INCREASE FACTOR */
 848                                                 incr = (uint32_t) (((uint64_t) net->net_ack *
 849                                                     (uint64_t) net->cwnd) /
 850                                                     ((uint64_t) srtt * t_ucwnd_sbw));
 851                                                 /* INCREASE FACTOR */
 852                                                 if (incr > limit) {
 853                                                         incr = limit;
 854                                                 }
 855                                                 if (incr == 0) {
 856                                                         incr = 1;
 857                                                 }
 858                                                 break;
 859                                         case SCTP_CMT_MPTCP:
 860                                                 limit = (uint32_t) (((uint64_t) net->mtu *
 861                                                     mptcp_like_alpha *
 862                                                     (uint64_t) SCTP_BASE_SYSCTL(sctp_L2_abc_variable)) >>
 863                                                     SHIFT_MPTCP_MULTI);
 864                                                 incr = (uint32_t) (((uint64_t) net->net_ack *
 865                                                     mptcp_like_alpha) >>
 866                                                     SHIFT_MPTCP_MULTI);
 867                                                 if (incr > limit) {
 868                                                         incr = limit;
 869                                                 }
 870                                                 if (incr > net->net_ack) {
 871                                                         incr = net->net_ack;
 872                                                 }
 873                                                 if (incr > net->mtu) {
 874                                                         incr = net->mtu;
 875                                                 }
 876                                                 break;
 877                                         default:
 878                                                 incr = net->net_ack;
 879                                                 if (incr > net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable)) {
 880                                                         incr = net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable);
 881                                                 }
 882                                                 break;
 883                                         }
 884                                         net->cwnd += incr;
 885                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 886                                                 sctp_log_cwnd(stcb, net, incr,
 887                                                     SCTP_CWND_LOG_FROM_SS);
 888                                         }
 889                                         SDT_PROBE(sctp, cwnd, net, ack,
 890                                             stcb->asoc.my_vtag,
 891                                             ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
 892                                             net,
 893                                             old_cwnd, net->cwnd);
 894                                 } else {
 895                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 896                                                 sctp_log_cwnd(stcb, net, net->net_ack,
 897                                                     SCTP_CWND_LOG_NOADV_SS);
 898                                         }
 899                                 }
 900                         } else {
 901                                 /* We are in congestion avoidance */
 902                                 /*
 903                                  * Add to pba
 904                                  */
 905                                 net->partial_bytes_acked += net->net_ack;
 906
 907                                 if ((net->flight_size + net->net_ack >= net->cwnd) &&
 908                                     (net->partial_bytes_acked >= net->cwnd)) {
 909                                         net->partial_bytes_acked -= net->cwnd;
 910                                         old_cwnd = net->cwnd;
 911                                         switch (asoc->sctp_cmt_on_off) {
 912                                         case SCTP_CMT_RPV1:
 913                                                 incr = (uint32_t) (((uint64_t) net->mtu *
 914                                                     (uint64_t) net->ssthresh) /
 915                                                     (uint64_t) t_ssthresh);
 916                                                 if (incr == 0) {
 917                                                         incr = 1;
 918                                                 }
 919                                                 break;
 920                                         case SCTP_CMT_RPV2:
 921                                                 /*
 922                                                  * lastsa>>3;  we don't need
 923                                                  * to divide ...
 924                                                  */
 925                                                 srtt = net->lastsa;
 926                                                 if (srtt == 0) {
 927                                                         srtt = 1;
 928                                                 }
 929                                                 incr = (uint32_t) ((uint64_t) net->mtu *
 930                                                     (uint64_t) net->cwnd /
 931                                                     ((uint64_t) srtt *
 932                                                     t_ucwnd_sbw));
 933                                                 /* INCREASE FACTOR */
 934                                                 if (incr == 0) {
 935                                                         incr = 1;
 936                                                 }
 937                                                 break;
 938                                         case SCTP_CMT_MPTCP:
 939                                                 incr = (uint32_t) ((mptcp_like_alpha *
 940                                                     (uint64_t) net->cwnd) >>
 941                                                     SHIFT_MPTCP_MULTI);
 942                                                 if (incr > net->mtu) {
 943                                                         incr = net->mtu;
 944                                                 }
 945                                                 break;
 946                                         default:
 947                                                 incr = net->mtu;
 948                                                 break;
 949                                         }
 950                                         net->cwnd += incr;
 951                                         SDT_PROBE(sctp, cwnd, net, ack,
 952                                             stcb->asoc.my_vtag,
 953                                             ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
 954                                             net,
 955                                             old_cwnd, net->cwnd);
 956                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 957                                                 sctp_log_cwnd(stcb, net, net->mtu,
 958                                                     SCTP_CWND_LOG_FROM_CA);
 959                                         }
 960                                 } else {
 961                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 962                                                 sctp_log_cwnd(stcb, net, net->net_ack,
 963                                                     SCTP_CWND_LOG_NOADV_CA);
 964                                         }
 965                                 }
 966                         }
 967                 } else {
 968                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 969                                 sctp_log_cwnd(stcb, net, net->mtu,
 970                                     SCTP_CWND_LOG_NO_CUMACK);
 971                         }
 972                 }
 973         }
 974 }
 975
 976 static void
 977 sctp_cwnd_update_exit_pf_common(struct sctp_tcb *stcb, struct sctp_nets *net)
 978 {
 979         int old_cwnd;
 980
 981         old_cwnd = net->cwnd;
 982         net->cwnd = net->mtu;
 983         SDT_PROBE(sctp, cwnd, net, ack,
 984             stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
 985             old_cwnd, net->cwnd);
 986         SCTPDBG(SCTP_DEBUG_INDATA1, "Destination %p moved from PF to reachable with cwnd %d.\n",
 987             (void *)net, net->cwnd);
 988 }
 989
 990
 991 static void
 992 sctp_cwnd_update_after_timeout(struct sctp_tcb *stcb, struct sctp_nets *net)
 993 {
 994         int old_cwnd = net->cwnd;
 995         uint32_t t_ssthresh, t_cwnd;
 996         uint64_t t_ucwnd_sbw;
 997
 998         /* MT FIXME: Don't compute this over and over again */
 999         t_ssthresh = 0;
1000         t_cwnd = 0;
1001         if ((stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) ||
1002             (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV2)) {
1003                 struct sctp_nets *lnet;
1004                 uint32_t srtt;
1005
1006                 t_ucwnd_sbw = 0;
1007                 TAILQ_FOREACH(lnet, &stcb->asoc.nets, sctp_next) {
1008                         t_ssthresh += lnet->ssthresh;
1009                         t_cwnd += lnet->cwnd;
1010                         srtt = lnet->lastsa;
1011                         /* lastsa>>3;  we don't need to divide ... */
1012                         if (srtt > 0) {
1013                                 t_ucwnd_sbw += (uint64_t) lnet->cwnd / (uint64_t) srtt;
1014                         }
1015                 }
1016                 if (t_ssthresh < 1) {
1017                         t_ssthresh = 1;
1018                 }
1019                 if (t_ucwnd_sbw < 1) {
1020                         t_ucwnd_sbw = 1;
1021                 }
1022                 if (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) {
1023                         net->ssthresh = (uint32_t) (((uint64_t) 4 *
1024                             (uint64_t) net->mtu *
1025                             (uint64_t) net->ssthresh) /
1026                             (uint64_t) t_ssthresh);
1027                 } else {
1028                         uint64_t cc_delta;
1029
1030                         srtt = net->lastsa;
1031                         /* lastsa>>3;  we don't need to divide ... */
1032                         if (srtt == 0) {
1033                                 srtt = 1;
1034                         }
1035                         cc_delta = t_ucwnd_sbw * (uint64_t) srtt / 2;
1036                         if (cc_delta < t_cwnd) {
1037                                 net->ssthresh = (uint32_t) ((uint64_t) t_cwnd - cc_delta);
1038                         } else {
1039                                 net->ssthresh = net->mtu;
1040                         }
1041                 }
1042                 if ((net->cwnd > t_cwnd / 2) &&
1043                     (net->ssthresh < net->cwnd - t_cwnd / 2)) {
1044                         net->ssthresh = net->cwnd - t_cwnd / 2;
1045                 }
1046                 if (net->ssthresh < net->mtu) {
1047                         net->ssthresh = net->mtu;
1048                 }
1049         } else {
1050                 net->ssthresh = max(net->cwnd / 2, 4 * net->mtu);
1051         }
1052         net->cwnd = net->mtu;
1053         net->partial_bytes_acked = 0;
1054         SDT_PROBE(sctp, cwnd, net, to,
1055             stcb->asoc.my_vtag,
1056             ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
1057             net,
1058             old_cwnd, net->cwnd);
1059         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1060                 sctp_log_cwnd(stcb, net, net->cwnd - old_cwnd, SCTP_CWND_LOG_FROM_RTX);
1061         }
1062 }
1063
1064 static void
1065 sctp_cwnd_update_after_ecn_echo_common(struct sctp_tcb *stcb, struct sctp_nets *net,
1066     int in_window, int num_pkt_lost, int use_rtcc)
1067 {
1068         int old_cwnd = net->cwnd;
1069
1070         if ((use_rtcc) && (net->lan_type == SCTP_LAN_LOCAL) && (net->cc_mod.rtcc.use_dccc_ecn)) {
1071                 /* Data center Congestion Control */
1072                 if (in_window == 0) {
1073                         /*
1074                          * Go to CA with the cwnd at the point we sent the
1075                          * TSN that was marked with a CE.
1076                          */
1077                         if (net->ecn_prev_cwnd < net->cwnd) {
1078                                 /* Restore to prev cwnd */
1079                                 net->cwnd = net->ecn_prev_cwnd - (net->mtu * num_pkt_lost);
1080                         } else {
1081                                 /* Just cut in 1/2 */
1082                                 net->cwnd /= 2;
1083                         }
1084                         /* Drop to CA */
1085                         net->ssthresh = net->cwnd - (num_pkt_lost * net->mtu);
1086                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1087                                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
1088                         }
1089                 } else {
1090                         /*
1091                          * Further tuning down required over the drastic
1092                          * orginal cut
1093                          */
1094                         net->ssthresh -= (net->mtu * num_pkt_lost);
1095                         net->cwnd -= (net->mtu * num_pkt_lost);
1096                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1097                                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
1098                         }
1099                 }
1100                 SCTP_STAT_INCR(sctps_ecnereducedcwnd);
1101         } else {
1102                 if (in_window == 0) {
1103                         SCTP_STAT_INCR(sctps_ecnereducedcwnd);
1104                         net->ssthresh = net->cwnd / 2;
1105                         if (net->ssthresh < net->mtu) {
1106                                 net->ssthresh = net->mtu;
1107                                 /*
1108                                  * here back off the timer as well, to slow
1109                                  * us down
1110                                  */
1111                                 net->RTO <<= 1;
1112                         }
1113                         net->cwnd = net->ssthresh;
1114                         SDT_PROBE(sctp, cwnd, net, ecn,
1115                             stcb->asoc.my_vtag,
1116                             ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
1117                             net,
1118                             old_cwnd, net->cwnd);
1119                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1120                                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
1121                         }
1122                 }
1123         }
1124
1125 }
1126
1127 static void
1128 sctp_cwnd_update_after_packet_dropped(struct sctp_tcb *stcb,
1129     struct sctp_nets *net, struct sctp_pktdrop_chunk *cp,
1130     uint32_t * bottle_bw, uint32_t * on_queue)
1131 {
1132         uint32_t bw_avail;
1133         int rtt;
1134         unsigned int incr;
1135         int old_cwnd = net->cwnd;
1136
1137         /* need real RTT in msd for this calc */
1138         rtt = net->rtt / 1000;
1139         /* get bottle neck bw */
1140         *bottle_bw = ntohl(cp->bottle_bw);
1141         /* and whats on queue */
1142         *on_queue = ntohl(cp->current_onq);
1143         /*
1144          * adjust the on-queue if our flight is more it could be that the
1145          * router has not yet gotten data "in-flight" to it
1146          */
1147         if (*on_queue < net->flight_size)
1148                 *on_queue = net->flight_size;
1149         /* calculate the available space */
1150         bw_avail = (*bottle_bw * rtt) / 1000;
1151         if (bw_avail > *bottle_bw) {
1152                 /*
1153                  * Cap the growth to no more than the bottle neck. This can
1154                  * happen as RTT slides up due to queues. It also means if
1155                  * you have more than a 1 second RTT with a empty queue you
1156                  * will be limited to the bottle_bw per second no matter if
1157                  * other points have 1/2 the RTT and you could get more
1158                  * out...
1159                  */
1160                 bw_avail = *bottle_bw;
1161         }
1162         if (*on_queue > bw_avail) {
1163                 /*
1164                  * No room for anything else don't allow anything else to be
1165                  * "added to the fire".
1166                  */
1167                 int seg_inflight, seg_onqueue, my_portion;
1168
1169                 net->partial_bytes_acked = 0;
1170
1171                 /* how much are we over queue size? */
1172                 incr = *on_queue - bw_avail;
1173                 if (stcb->asoc.seen_a_sack_this_pkt) {
1174                         /*
1175                          * undo any cwnd adjustment that the sack might have
1176                          * made
1177                          */
1178                         net->cwnd = net->prev_cwnd;
1179                 }
1180                 /* Now how much of that is mine? */
1181                 seg_inflight = net->flight_size / net->mtu;
1182                 seg_onqueue = *on_queue / net->mtu;
1183                 my_portion = (incr * seg_inflight) / seg_onqueue;
1184
1185                 /* Have I made an adjustment already */
1186                 if (net->cwnd > net->flight_size) {
1187                         /*
1188                          * for this flight I made an adjustment we need to
1189                          * decrease the portion by a share our previous
1190                          * adjustment.
1191                          */
1192                         int diff_adj;
1193
1194                         diff_adj = net->cwnd - net->flight_size;
1195                         if (diff_adj > my_portion)
1196                                 my_portion = 0;
1197                         else
1198                                 my_portion -= diff_adj;
1199                 }
1200                 /*
1201                  * back down to the previous cwnd (assume we have had a sack
1202                  * before this packet). minus what ever portion of the
1203                  * overage is my fault.
1204                  */
1205                 net->cwnd -= my_portion;
1206
1207                 /* we will NOT back down more than 1 MTU */
1208                 if (net->cwnd <= net->mtu) {
1209                         net->cwnd = net->mtu;
1210                 }
1211                 /* force into CA */
1212                 net->ssthresh = net->cwnd - 1;
1213         } else {
1214                 /*
1215                  * Take 1/4 of the space left or max burst up .. whichever
1216                  * is less.
1217                  */
1218                 incr = (bw_avail - *on_queue) >> 2;
1219                 if ((stcb->asoc.max_burst > 0) &&
1220                     (stcb->asoc.max_burst * net->mtu < incr)) {
1221                         incr = stcb->asoc.max_burst * net->mtu;
1222                 }
1223                 net->cwnd += incr;
1224         }
1225         if (net->cwnd > bw_avail) {
1226                 /* We can't exceed the pipe size */
1227                 net->cwnd = bw_avail;
1228         }
1229         if (net->cwnd < net->mtu) {
1230                 /* We always have 1 MTU */
1231                 net->cwnd = net->mtu;
1232         }
1233         if (net->cwnd - old_cwnd != 0) {
1234                 /* log only changes */
1235                 SDT_PROBE(sctp, cwnd, net, pd,
1236                     stcb->asoc.my_vtag,
1237                     ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
1238                     net,
1239                     old_cwnd, net->cwnd);
1240                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1241                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
1242                             SCTP_CWND_LOG_FROM_SAT);
1243                 }
1244         }
1245 }
1246
1247 static void
1248 sctp_cwnd_update_after_output(struct sctp_tcb *stcb,
1249     struct sctp_nets *net, int burst_limit)
1250 {
1251         int old_cwnd = net->cwnd;
1252
1253         if (net->ssthresh < net->cwnd)
1254                 net->ssthresh = net->cwnd;
1255         if (burst_limit) {
1256                 net->cwnd = (net->flight_size + (burst_limit * net->mtu));
1257                 SDT_PROBE(sctp, cwnd, net, bl,
1258                     stcb->asoc.my_vtag,
1259                     ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
1260                     net,
1261                     old_cwnd, net->cwnd);
1262                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1263                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_BRST);
1264                 }
1265         }
1266 }
1267
1268 static void
1269 sctp_cwnd_update_after_sack(struct sctp_tcb *stcb,
1270     struct sctp_association *asoc,
1271     int accum_moved, int reneged_all, int will_exit)
1272 {
1273         /* Passing a zero argument in last disables the rtcc algoritm */
1274         sctp_cwnd_update_after_sack_common(stcb, asoc, accum_moved, reneged_all, will_exit, 0);
1275 }
1276
1277 static void
1278 sctp_cwnd_update_after_ecn_echo(struct sctp_tcb *stcb, struct sctp_nets *net,
1279     int in_window, int num_pkt_lost)
1280 {
1281         /* Passing a zero argument in last disables the rtcc algoritm */
1282         sctp_cwnd_update_after_ecn_echo_common(stcb, net, in_window, num_pkt_lost, 0);
1283 }
1284
1285 /* Here starts the RTCCVAR type CC invented by RRS which
1286  * is a slight mod to RFC2581. We reuse a common routine or
1287  * two since these algoritms are so close and need to
1288  * remain the same.
1289  */
1290 static void
1291 sctp_cwnd_update_rtcc_after_ecn_echo(struct sctp_tcb *stcb, struct sctp_nets *net,
1292     int in_window, int num_pkt_lost)
1293 {
1294         sctp_cwnd_update_after_ecn_echo_common(stcb, net, in_window, num_pkt_lost, 1);
1295 }
1296
1297
1298 static
1299 void
1300 sctp_cwnd_update_rtcc_tsn_acknowledged(struct sctp_nets *net,
1301     struct sctp_tmit_chunk *tp1)
1302 {
1303         net->cc_mod.rtcc.bw_bytes += tp1->send_size;
1304 }
1305
1306 static void
1307 sctp_cwnd_prepare_rtcc_net_for_sack(struct sctp_tcb *stcb SCTP_UNUSED,
1308     struct sctp_nets *net)
1309 {
1310         if (net->cc_mod.rtcc.tls_needs_set > 0) {
1311                 /* We had a bw measurment going on */
1312                 struct timeval ltls;
1313
1314                 SCTP_GETPTIME_TIMEVAL(&ltls);
1315                 timevalsub(&ltls, &net->cc_mod.rtcc.tls);
1316                 net->cc_mod.rtcc.new_tot_time = (ltls.tv_sec * 1000000) + ltls.tv_usec;
1317         }
1318 }
1319
1320 static void
1321 sctp_cwnd_new_rtcc_transmission_begins(struct sctp_tcb *stcb,
1322     struct sctp_nets *net)
1323 {
1324         uint64_t vtag, probepoint;
1325
1326         if (net->cc_mod.rtcc.lbw) {
1327                 /* Clear the old bw.. we went to 0 in-flight */
1328                 vtag = (net->rtt << 32) | (((uint32_t) (stcb->sctp_ep->sctp_lport)) << 16) |
1329                     (stcb->rport);
1330                 probepoint = (((uint64_t) net->cwnd) << 32);
1331                 /* Probe point 8 */
1332                 probepoint |= ((8 << 16) | 0);
1333                 SDT_PROBE(sctp, cwnd, net, rttvar,
1334                     vtag,
1335                     ((net->cc_mod.rtcc.lbw << 32) | 0),
1336                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
1337                     net->flight_size,
1338                     probepoint);
1339                 net->cc_mod.rtcc.lbw_rtt = 0;
1340                 net->cc_mod.rtcc.cwnd_at_bw_set = 0;
1341                 net->cc_mod.rtcc.lbw = 0;
1342                 net->cc_mod.rtcc.bw_bytes_at_last_rttc = 0;
1343                 net->cc_mod.rtcc.vol_reduce = 0;
1344                 net->cc_mod.rtcc.bw_tot_time = 0;
1345                 net->cc_mod.rtcc.bw_bytes = 0;
1346                 net->cc_mod.rtcc.tls_needs_set = 0;
1347                 if (net->cc_mod.rtcc.steady_step) {
1348                         net->cc_mod.rtcc.vol_reduce = 0;
1349                         net->cc_mod.rtcc.step_cnt = 0;
1350                         net->cc_mod.rtcc.last_step_state = 0;
1351                 }
1352                 if (net->cc_mod.rtcc.ret_from_eq) {
1353                         /* less aggressive one - reset cwnd too */
1354                         uint32_t cwnd_in_mtu, cwnd;
1355
1356                         cwnd_in_mtu = SCTP_BASE_SYSCTL(sctp_initial_cwnd);
1357                         if (cwnd_in_mtu == 0) {
1358                                 /*
1359                                  * Using 0 means that the value of RFC 4960
1360                                  * is used.
1361                                  */
1362                                 cwnd = min((net->mtu * 4), max((2 * net->mtu), SCTP_INITIAL_CWND));
1363                         } else {
1364                                 /*
1365                                  * We take the minimum of the burst limit
1366                                  * and the initial congestion window.
1367                                  */
1368                                 if ((stcb->asoc.max_burst > 0) && (cwnd_in_mtu > stcb->asoc.max_burst))
1369                                         cwnd_in_mtu = stcb->asoc.max_burst;
1370                                 cwnd = (net->mtu - sizeof(struct sctphdr)) * cwnd_in_mtu;
1371                         }
1372                         if (net->cwnd > cwnd) {
1373                                 /*
1374                                  * Only set if we are not a timeout (i.e.
1375                                  * down to 1 mtu)
1376                                  */
1377                                 net->cwnd = cwnd;
1378                         }
1379                 }
1380         }
1381 }
1382
1383 static void
1384 sctp_set_rtcc_initial_cc_param(struct sctp_tcb *stcb,
1385     struct sctp_nets *net)
1386 {
1387         uint64_t vtag, probepoint;
1388
1389         sctp_set_initial_cc_param(stcb, net);
1390         stcb->asoc.use_precise_time = 1;
1391         probepoint = (((uint64_t) net->cwnd) << 32);
1392         probepoint |= ((9 << 16) | 0);
1393         vtag = (net->rtt << 32) |
1394             (((uint32_t) (stcb->sctp_ep->sctp_lport)) << 16) |
1395             (stcb->rport);
1396         SDT_PROBE(sctp, cwnd, net, rttvar,
1397             vtag,
1398             0,
1399             0,
1400             0,
1401             probepoint);
1402         net->cc_mod.rtcc.lbw_rtt = 0;
1403         net->cc_mod.rtcc.cwnd_at_bw_set = 0;
1404         net->cc_mod.rtcc.vol_reduce = 0;
1405         net->cc_mod.rtcc.lbw = 0;
1406         net->cc_mod.rtcc.vol_reduce = 0;
1407         net->cc_mod.rtcc.bw_bytes_at_last_rttc = 0;
1408         net->cc_mod.rtcc.bw_tot_time = 0;
1409         net->cc_mod.rtcc.bw_bytes = 0;
1410         net->cc_mod.rtcc.tls_needs_set = 0;
1411         net->cc_mod.rtcc.ret_from_eq = SCTP_BASE_SYSCTL(sctp_rttvar_eqret);
1412         net->cc_mod.rtcc.steady_step = SCTP_BASE_SYSCTL(sctp_steady_step);
1413         net->cc_mod.rtcc.use_dccc_ecn = SCTP_BASE_SYSCTL(sctp_use_dccc_ecn);
1414         net->cc_mod.rtcc.step_cnt = 0;
1415         net->cc_mod.rtcc.last_step_state = 0;
1416
1417
1418 }
1419
1420 static int
1421 sctp_cwnd_rtcc_socket_option(struct sctp_tcb *stcb, int setorget,
1422     struct sctp_cc_option *cc_opt)
1423 {
1424         struct sctp_nets *net;
1425
1426         if (setorget == 1) {
1427                 /* a set */
1428                 if (cc_opt->option == SCTP_CC_OPT_RTCC_SETMODE) {
1429                         if ((cc_opt->aid_value.assoc_value != 0) &&
1430                             (cc_opt->aid_value.assoc_value != 1)) {
1431                                 return (EINVAL);
1432                         }
1433                         TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
1434                                 net->cc_mod.rtcc.ret_from_eq = cc_opt->aid_value.assoc_value;
1435                         }
1436                 } else if (cc_opt->option == SCTP_CC_OPT_USE_DCCC_ECN) {
1437                         if ((cc_opt->aid_value.assoc_value != 0) &&
1438                             (cc_opt->aid_value.assoc_value != 1)) {
1439                                 return (EINVAL);
1440                         }
1441                         TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
1442                                 net->cc_mod.rtcc.use_dccc_ecn = cc_opt->aid_value.assoc_value;
1443                         }
1444                 } else if (cc_opt->option == SCTP_CC_OPT_STEADY_STEP) {
1445                         TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
1446                                 net->cc_mod.rtcc.steady_step = cc_opt->aid_value.assoc_value;
1447                         }
1448                 } else {
1449                         return (EINVAL);
1450                 }
1451         } else {
1452                 /* a get */
1453                 if (cc_opt->option == SCTP_CC_OPT_RTCC_SETMODE) {
1454                         net = TAILQ_FIRST(&stcb->asoc.nets);
1455                         if (net == NULL) {
1456                                 return (EFAULT);
1457                         }
1458                         cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.ret_from_eq;
1459                 } else if (cc_opt->option == SCTP_CC_OPT_USE_DCCC_ECN) {
1460                         net = TAILQ_FIRST(&stcb->asoc.nets);
1461                         if (net == NULL) {
1462                                 return (EFAULT);
1463                         }
1464                         cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.use_dccc_ecn;
1465                 } else if (cc_opt->option == SCTP_CC_OPT_STEADY_STEP) {
1466                         net = TAILQ_FIRST(&stcb->asoc.nets);
1467                         if (net == NULL) {
1468                                 return (EFAULT);
1469                         }
1470                         cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.steady_step;
1471                 } else {
1472                         return (EINVAL);
1473                 }
1474         }
1475         return (0);
1476 }
1477
1478 static void
1479 sctp_cwnd_update_rtcc_packet_transmitted(struct sctp_tcb *stcb SCTP_UNUSED,
1480     struct sctp_nets *net)
1481 {
1482         if (net->cc_mod.rtcc.tls_needs_set == 0) {
1483                 SCTP_GETPTIME_TIMEVAL(&net->cc_mod.rtcc.tls);
1484                 net->cc_mod.rtcc.tls_needs_set = 2;
1485         }
1486 }
1487
1488 static void
1489 sctp_cwnd_update_rtcc_after_sack(struct sctp_tcb *stcb,
1490     struct sctp_association *asoc,
1491     int accum_moved, int reneged_all, int will_exit)
1492 {
1493         /* Passing a one argument at the last enables the rtcc algoritm */
1494         sctp_cwnd_update_after_sack_common(stcb, asoc, accum_moved, reneged_all, will_exit, 1);
1495 }
1496
1497 static void
1498 sctp_rtt_rtcc_calculated(struct sctp_tcb *stcb SCTP_UNUSED,
1499     struct sctp_nets *net,
1500     struct timeval *now SCTP_UNUSED)
1501 {
1502         net->cc_mod.rtcc.rtt_set_this_sack = 1;
1503 }
1504
1505 /* Here starts Sally Floyds HS-TCP */
1506
1507 struct sctp_hs_raise_drop {
1508         int32_t cwnd;
1509         int32_t increase;
1510         int32_t drop_percent;
1511 };
1512
1513 #define SCTP_HS_TABLE_SIZE 73
1514
1515 struct sctp_hs_raise_drop sctp_cwnd_adjust[SCTP_HS_TABLE_SIZE] = {
1516         {38, 1, 50},            /* 0   */
1517         {118, 2, 44},           /* 1   */
1518         {221, 3, 41},           /* 2   */
1519         {347, 4, 38},           /* 3   */
1520         {495, 5, 37},           /* 4   */
1521         {663, 6, 35},           /* 5   */
1522         {851, 7, 34},           /* 6   */
1523         {1058, 8, 33},          /* 7   */
1524         {1284, 9, 32},          /* 8   */
1525         {1529, 10, 31},         /* 9   */
1526         {1793, 11, 30},         /* 10  */
1527         {2076, 12, 29},         /* 11  */
1528         {2378, 13, 28},         /* 12  */
1529         {2699, 14, 28},         /* 13  */
1530         {3039, 15, 27},         /* 14  */
1531         {3399, 16, 27},         /* 15  */
1532         {3778, 17, 26},         /* 16  */
1533         {4177, 18, 26},         /* 17  */
1534         {4596, 19, 25},         /* 18  */
1535         {5036, 20, 25},         /* 19  */
1536         {5497, 21, 24},         /* 20  */
1537         {5979, 22, 24},         /* 21  */
1538         {6483, 23, 23},         /* 22  */
1539         {7009, 24, 23},         /* 23  */
1540         {7558, 25, 22},         /* 24  */
1541         {8130, 26, 22},         /* 25  */
1542         {8726, 27, 22},         /* 26  */
1543         {9346, 28, 21},         /* 27  */
1544         {9991, 29, 21},         /* 28  */
1545         {10661, 30, 21},        /* 29  */
1546         {11358, 31, 20},        /* 30  */
1547         {12082, 32, 20},        /* 31  */
1548         {12834, 33, 20},        /* 32  */
1549         {13614, 34, 19},        /* 33  */
1550         {14424, 35, 19},        /* 34  */
1551         {15265, 36, 19},        /* 35  */
1552         {16137, 37, 19},        /* 36  */
1553         {17042, 38, 18},        /* 37  */
1554         {17981, 39, 18},        /* 38  */
1555         {18955, 40, 18},        /* 39  */
1556         {19965, 41, 17},        /* 40  */
1557         {21013, 42, 17},        /* 41  */
1558         {22101, 43, 17},        /* 42  */
1559         {23230, 44, 17},        /* 43  */
1560         {24402, 45, 16},        /* 44  */
1561         {25618, 46, 16},        /* 45  */
1562         {26881, 47, 16},        /* 46  */
1563         {28193, 48, 16},        /* 47  */
1564         {29557, 49, 15},        /* 48  */
1565         {30975, 50, 15},        /* 49  */
1566         {32450, 51, 15},        /* 50  */
1567         {33986, 52, 15},        /* 51  */
1568         {35586, 53, 14},        /* 52  */
1569         {37253, 54, 14},        /* 53  */
1570         {38992, 55, 14},        /* 54  */
1571         {40808, 56, 14},        /* 55  */
1572         {42707, 57, 13},        /* 56  */
1573         {44694, 58, 13},        /* 57  */
1574         {46776, 59, 13},        /* 58  */
1575         {48961, 60, 13},        /* 59  */
1576         {51258, 61, 13},        /* 60  */
1577         {53677, 62, 12},        /* 61  */
1578         {56230, 63, 12},        /* 62  */
1579         {58932, 64, 12},        /* 63  */
1580         {61799, 65, 12},        /* 64  */
1581         {64851, 66, 11},        /* 65  */
1582         {68113, 67, 11},        /* 66  */
1583         {71617, 68, 11},        /* 67  */
1584         {75401, 69, 10},        /* 68  */
1585         {79517, 70, 10},        /* 69  */
1586         {84035, 71, 10},        /* 70  */
1587         {89053, 72, 10},        /* 71  */
1588         {94717, 73, 9}          /* 72  */
1589 };
1590
1591 static void
1592 sctp_hs_cwnd_increase(struct sctp_tcb *stcb, struct sctp_nets *net)
1593 {
1594         int cur_val, i, indx, incr;
1595
1596         cur_val = net->cwnd >> 10;
1597         indx = SCTP_HS_TABLE_SIZE - 1;
1598
1599         if (cur_val < sctp_cwnd_adjust[0].cwnd) {
1600                 /* normal mode */
1601                 if (net->net_ack > net->mtu) {
1602                         net->cwnd += net->mtu;
1603                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1604                                 sctp_log_cwnd(stcb, net, net->mtu, SCTP_CWND_LOG_FROM_SS);
1605                         }
1606                 } else {
1607                         net->cwnd += net->net_ack;
1608                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1609                                 sctp_log_cwnd(stcb, net, net->net_ack, SCTP_CWND_LOG_FROM_SS);
1610                         }
1611                 }
1612         } else {
1613                 for (i = net->last_hs_used; i < SCTP_HS_TABLE_SIZE; i++) {
1614                         if (cur_val < sctp_cwnd_adjust[i].cwnd) {
1615                                 indx = i;
1616                                 break;
1617                         }
1618                 }
1619                 net->last_hs_used = indx;
1620                 incr = ((sctp_cwnd_adjust[indx].increase) << 10);
1621                 net->cwnd += incr;
1622                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1623                         sctp_log_cwnd(stcb, net, incr, SCTP_CWND_LOG_FROM_SS);
1624                 }
1625         }
1626 }
1627
1628 static void
1629 sctp_hs_cwnd_decrease(struct sctp_tcb *stcb, struct sctp_nets *net)
1630 {
1631         int cur_val, i, indx;
1632         int old_cwnd = net->cwnd;
1633
1634         cur_val = net->cwnd >> 10;
1635         if (cur_val < sctp_cwnd_adjust[0].cwnd) {
1636                 /* normal mode */
1637                 net->ssthresh = net->cwnd / 2;
1638                 if (net->ssthresh < (net->mtu * 2)) {
1639                         net->ssthresh = 2 * net->mtu;
1640                 }
1641                 net->cwnd = net->ssthresh;
1642         } else {
1643                 /* drop by the proper amount */
1644                 net->ssthresh = net->cwnd - (int)((net->cwnd / 100) *
1645                     sctp_cwnd_adjust[net->last_hs_used].drop_percent);
1646                 net->cwnd = net->ssthresh;
1647                 /* now where are we */
1648                 indx = net->last_hs_used;
1649                 cur_val = net->cwnd >> 10;
1650                 /* reset where we are in the table */
1651                 if (cur_val < sctp_cwnd_adjust[0].cwnd) {
1652                         /* feel out of hs */
1653                         net->last_hs_used = 0;
1654                 } else {
1655                         for (i = indx; i >= 1; i--) {
1656                                 if (cur_val > sctp_cwnd_adjust[i - 1].cwnd) {
1657                                         break;
1658                                 }
1659                         }
1660                         net->last_hs_used = indx;
1661                 }
1662         }
1663         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1664                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_FR);
1665         }
1666 }
1667
1668 static void
1669 sctp_hs_cwnd_update_after_fr(struct sctp_tcb *stcb,
1670     struct sctp_association *asoc)
1671 {
1672         struct sctp_nets *net;
1673
1674         /*
1675          * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off > 0) &&
1676          * (net->fast_retran_loss_recovery == 0)))
1677          */
1678         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
1679                 if ((asoc->fast_retran_loss_recovery == 0) ||
1680                     (asoc->sctp_cmt_on_off > 0)) {
1681                         /* out of a RFC2582 Fast recovery window? */
1682                         if (net->net_ack > 0) {
1683                                 /*
1684                                  * per section 7.2.3, are there any
1685                                  * destinations that had a fast retransmit
1686                                  * to them. If so what we need to do is
1687                                  * adjust ssthresh and cwnd.
1688                                  */
1689                                 struct sctp_tmit_chunk *lchk;
1690
1691                                 sctp_hs_cwnd_decrease(stcb, net);
1692
1693                                 lchk = TAILQ_FIRST(&asoc->send_queue);
1694
1695                                 net->partial_bytes_acked = 0;
1696                                 /* Turn on fast recovery window */
1697                                 asoc->fast_retran_loss_recovery = 1;
1698                                 if (lchk == NULL) {
1699                                         /* Mark end of the window */
1700                                         asoc->fast_recovery_tsn = asoc->sending_seq - 1;
1701                                 } else {
1702                                         asoc->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
1703                                 }
1704
1705                                 /*
1706                                  * CMT fast recovery -- per destination
1707                                  * recovery variable.
1708                                  */
1709                                 net->fast_retran_loss_recovery = 1;
1710
1711                                 if (lchk == NULL) {
1712                                         /* Mark end of the window */
1713                                         net->fast_recovery_tsn = asoc->sending_seq - 1;
1714                                 } else {
1715                                         net->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
1716                                 }
1717
1718                                 sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
1719                                     stcb->sctp_ep, stcb, net, SCTP_FROM_SCTP_INDATA + SCTP_LOC_32);
1720                                 sctp_timer_start(SCTP_TIMER_TYPE_SEND,
1721                                     stcb->sctp_ep, stcb, net);
1722                         }
1723                 } else if (net->net_ack > 0) {
1724                         /*
1725                          * Mark a peg that we WOULD have done a cwnd
1726                          * reduction but RFC2582 prevented this action.
1727                          */
1728                         SCTP_STAT_INCR(sctps_fastretransinrtt);
1729                 }
1730         }
1731 }
1732
1733 static void
1734 sctp_hs_cwnd_update_after_sack(struct sctp_tcb *stcb,
1735     struct sctp_association *asoc,
1736     int accum_moved, int reneged_all SCTP_UNUSED, int will_exit)
1737 {
1738         struct sctp_nets *net;
1739
1740         /******************************/
1741         /* update cwnd and Early FR   */
1742         /******************************/
1743         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
1744
1745 #ifdef JANA_CMT_FAST_RECOVERY
1746                 /*
1747                  * CMT fast recovery code. Need to debug.
1748                  */
1749                 if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
1750                         if (SCTP_TSN_GE(asoc->last_acked_seq, net->fast_recovery_tsn) ||
1751                             SCTP_TSN_GE(net->pseudo_cumack, net->fast_recovery_tsn)) {
1752                                 net->will_exit_fast_recovery = 1;
1753                         }
1754                 }
1755 #endif
1756                 /* if nothing was acked on this destination skip it */
1757                 if (net->net_ack == 0) {
1758                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1759                                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
1760                         }
1761                         continue;
1762                 }
1763 #ifdef JANA_CMT_FAST_RECOVERY
1764                 /*
1765                  * CMT fast recovery code
1766                  */
1767                 /*
1768                  * if (sctp_cmt_on_off > 0 && net->fast_retran_loss_recovery
1769                  * && net->will_exit_fast_recovery == 0) { @@@ Do something
1770                  * } else if (sctp_cmt_on_off == 0 &&
1771                  * asoc->fast_retran_loss_recovery && will_exit == 0) {
1772                  */
1773 #endif
1774
1775                 if (asoc->fast_retran_loss_recovery &&
1776                     (will_exit == 0) &&
1777                     (asoc->sctp_cmt_on_off == 0)) {
1778                         /*
1779                          * If we are in loss recovery we skip any cwnd
1780                          * update
1781                          */
1782                         return;
1783                 }
1784                 /*
1785                  * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
1786                  * moved.
1787                  */
1788                 if (accum_moved ||
1789                     ((asoc->sctp_cmt_on_off > 0) && net->new_pseudo_cumack)) {
1790                         /* If the cumulative ack moved we can proceed */
1791                         if (net->cwnd <= net->ssthresh) {
1792                                 /* We are in slow start */
1793                                 if (net->flight_size + net->net_ack >= net->cwnd) {
1794
1795                                         sctp_hs_cwnd_increase(stcb, net);
1796
1797                                 } else {
1798                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1799                                                 sctp_log_cwnd(stcb, net, net->net_ack,
1800                                                     SCTP_CWND_LOG_NOADV_SS);
1801                                         }
1802                                 }
1803                         } else {
1804                                 /* We are in congestion avoidance */
1805                                 net->partial_bytes_acked += net->net_ack;
1806                                 if ((net->flight_size + net->net_ack >= net->cwnd) &&
1807                                     (net->partial_bytes_acked >= net->cwnd)) {
1808                                         net->partial_bytes_acked -= net->cwnd;
1809                                         net->cwnd += net->mtu;
1810                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1811                                                 sctp_log_cwnd(stcb, net, net->mtu,
1812                                                     SCTP_CWND_LOG_FROM_CA);
1813                                         }
1814                                 } else {
1815                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1816                                                 sctp_log_cwnd(stcb, net, net->net_ack,
1817                                                     SCTP_CWND_LOG_NOADV_CA);
1818                                         }
1819                                 }
1820                         }
1821                 } else {
1822                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1823                                 sctp_log_cwnd(stcb, net, net->mtu,
1824                                     SCTP_CWND_LOG_NO_CUMACK);
1825                         }
1826                 }
1827         }
1828 }
1829
1830
1831 /*
1832  * H-TCP congestion control. The algorithm is detailed in:
1833  * R.N.Shorten, D.J.Leith:
1834  *   "H-TCP: TCP for high-speed and long-distance networks"
1835  *   Proc. PFLDnet, Argonne, 2004.
1836  * http://www.hamilton.ie/net/htcp3.pdf
1837  */
1838
1839
1840 static int use_rtt_scaling = 1;
1841 static int use_bandwidth_switch = 1;
1842
1843 static inline int
1844 between(uint32_t seq1, uint32_t seq2, uint32_t seq3)
1845 {
1846         return (seq3 - seq2 >= seq1 - seq2);
1847 }
1848
1849 static inline uint32_t
1850 htcp_cong_time(struct htcp *ca)
1851 {
1852         return (sctp_get_tick_count() - ca->last_cong);
1853 }
1854
1855 static inline uint32_t
1856 htcp_ccount(struct htcp *ca)
1857 {
1858         return (htcp_cong_time(ca) / ca->minRTT);
1859 }
1860
1861 static inline void
1862 htcp_reset(struct htcp *ca)
1863 {
1864         ca->undo_last_cong = ca->last_cong;
1865         ca->undo_maxRTT = ca->maxRTT;
1866         ca->undo_old_maxB = ca->old_maxB;
1867         ca->last_cong = sctp_get_tick_count();
1868 }
1869
1870 #ifdef SCTP_NOT_USED
1871
1872 static uint32_t
1873 htcp_cwnd_undo(struct sctp_tcb *stcb, struct sctp_nets *net)
1874 {
1875         net->cc_mod.htcp_ca.last_cong = net->cc_mod.htcp_ca.undo_last_cong;
1876         net->cc_mod.htcp_ca.maxRTT = net->cc_mod.htcp_ca.undo_maxRTT;
1877         net->cc_mod.htcp_ca.old_maxB = net->cc_mod.htcp_ca.undo_old_maxB;
1878         return (max(net->cwnd, ((net->ssthresh / net->mtu << 7) / net->cc_mod.htcp_ca.beta) * net->mtu));
1879 }
1880
1881 #endif
1882
1883 static inline void
1884 measure_rtt(struct sctp_nets *net)
1885 {
1886         uint32_t srtt = net->lastsa >> SCTP_RTT_SHIFT;
1887
1888         /* keep track of minimum RTT seen so far, minRTT is zero at first */
1889         if (net->cc_mod.htcp_ca.minRTT > srtt || !net->cc_mod.htcp_ca.minRTT)
1890                 net->cc_mod.htcp_ca.minRTT = srtt;
1891
1892         /* max RTT */
1893         if (net->fast_retran_ip == 0 && net->ssthresh < 0xFFFF && htcp_ccount(&net->cc_mod.htcp_ca) > 3) {
1894                 if (net->cc_mod.htcp_ca.maxRTT < net->cc_mod.htcp_ca.minRTT)
1895                         net->cc_mod.htcp_ca.maxRTT = net->cc_mod.htcp_ca.minRTT;
1896                 if (net->cc_mod.htcp_ca.maxRTT < srtt && srtt <= net->cc_mod.htcp_ca.maxRTT + MSEC_TO_TICKS(20))
1897                         net->cc_mod.htcp_ca.maxRTT = srtt;
1898         }
1899 }
1900
1901 static void
1902 measure_achieved_throughput(struct sctp_nets *net)
1903 {
1904         uint32_t now = sctp_get_tick_count();
1905
1906         if (net->fast_retran_ip == 0)
1907                 net->cc_mod.htcp_ca.bytes_acked = net->net_ack;
1908
1909         if (!use_bandwidth_switch)
1910                 return;
1911
1912         /* achieved throughput calculations */
1913         /* JRS - not 100% sure of this statement */
1914         if (net->fast_retran_ip == 1) {
1915                 net->cc_mod.htcp_ca.bytecount = 0;
1916                 net->cc_mod.htcp_ca.lasttime = now;
1917                 return;
1918         }
1919         net->cc_mod.htcp_ca.bytecount += net->net_ack;
1920         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)) &&
1921             (now - net->cc_mod.htcp_ca.lasttime >= net->cc_mod.htcp_ca.minRTT) &&
1922             (net->cc_mod.htcp_ca.minRTT > 0)) {
1923                 uint32_t cur_Bi = net->cc_mod.htcp_ca.bytecount / net->mtu * hz / (now - net->cc_mod.htcp_ca.lasttime);
1924
1925                 if (htcp_ccount(&net->cc_mod.htcp_ca) <= 3) {
1926                         /* just after backoff */
1927                         net->cc_mod.htcp_ca.minB = net->cc_mod.htcp_ca.maxB = net->cc_mod.htcp_ca.Bi = cur_Bi;
1928                 } else {
1929                         net->cc_mod.htcp_ca.Bi = (3 * net->cc_mod.htcp_ca.Bi + cur_Bi) / 4;
1930                         if (net->cc_mod.htcp_ca.Bi > net->cc_mod.htcp_ca.maxB)
1931                                 net->cc_mod.htcp_ca.maxB = net->cc_mod.htcp_ca.Bi;
1932                         if (net->cc_mod.htcp_ca.minB > net->cc_mod.htcp_ca.maxB)
1933                                 net->cc_mod.htcp_ca.minB = net->cc_mod.htcp_ca.maxB;
1934                 }
1935                 net->cc_mod.htcp_ca.bytecount = 0;
1936                 net->cc_mod.htcp_ca.lasttime = now;
1937         }
1938 }
1939
1940 static inline void
1941 htcp_beta_update(struct htcp *ca, uint32_t minRTT, uint32_t maxRTT)
1942 {
1943         if (use_bandwidth_switch) {
1944                 uint32_t maxB = ca->maxB;
1945                 uint32_t old_maxB = ca->old_maxB;
1946
1947                 ca->old_maxB = ca->maxB;
1948
1949                 if (!between(5 * maxB, 4 * old_maxB, 6 * old_maxB)) {
1950                         ca->beta = BETA_MIN;
1951                         ca->modeswitch = 0;
1952                         return;
1953                 }
1954         }
1955         if (ca->modeswitch && minRTT > (uint32_t) MSEC_TO_TICKS(10) && maxRTT) {
1956                 ca->beta = (minRTT << 7) / maxRTT;
1957                 if (ca->beta < BETA_MIN)
1958                         ca->beta = BETA_MIN;
1959                 else if (ca->beta > BETA_MAX)
1960                         ca->beta = BETA_MAX;
1961         } else {
1962                 ca->beta = BETA_MIN;
1963                 ca->modeswitch = 1;
1964         }
1965 }
1966
1967 static inline void
1968 htcp_alpha_update(struct htcp *ca)
1969 {
1970         uint32_t minRTT = ca->minRTT;
1971         uint32_t factor = 1;
1972         uint32_t diff = htcp_cong_time(ca);
1973
1974         if (diff > (uint32_t) hz) {
1975                 diff -= hz;
1976                 factor = 1 + (10 * diff + ((diff / 2) * (diff / 2) / hz)) / hz;
1977         }
1978         if (use_rtt_scaling && minRTT) {
1979                 uint32_t scale = (hz << 3) / (10 * minRTT);
1980
1981                 scale = min(max(scale, 1U << 2), 10U << 3);     /* clamping ratio to
1982                                                                  * interval [0.5,10]<<3 */
1983                 factor = (factor << 3) / scale;
1984                 if (!factor)
1985                         factor = 1;
1986         }
1987         ca->alpha = 2 * factor * ((1 << 7) - ca->beta);
1988         if (!ca->alpha)
1989                 ca->alpha = ALPHA_BASE;
1990 }
1991
1992 /* After we have the rtt data to calculate beta, we'd still prefer to wait one
1993  * rtt before we adjust our beta to ensure we are working from a consistent
1994  * data.
1995  *
1996  * This function should be called when we hit a congestion event since only at
1997  * that point do we really have a real sense of maxRTT (the queues en route
1998  * were getting just too full now).
1999  */
2000 static void
2001 htcp_param_update(struct sctp_nets *net)
2002 {
2003         uint32_t minRTT = net->cc_mod.htcp_ca.minRTT;
2004         uint32_t maxRTT = net->cc_mod.htcp_ca.maxRTT;
2005
2006         htcp_beta_update(&net->cc_mod.htcp_ca, minRTT, maxRTT);
2007         htcp_alpha_update(&net->cc_mod.htcp_ca);
2008
2009         /*
2010          * add slowly fading memory for maxRTT to accommodate routing
2011          * changes etc
2012          */
2013         if (minRTT > 0 && maxRTT > minRTT)
2014                 net->cc_mod.htcp_ca.maxRTT = minRTT + ((maxRTT - minRTT) * 95) / 100;
2015 }
2016
2017 static uint32_t
2018 htcp_recalc_ssthresh(struct sctp_nets *net)
2019 {
2020         htcp_param_update(net);
2021         return (max(((net->cwnd / net->mtu * net->cc_mod.htcp_ca.beta) >> 7) * net->mtu, 2U * net->mtu));
2022 }
2023
2024 static void
2025 htcp_cong_avoid(struct sctp_tcb *stcb, struct sctp_nets *net)
2026 {
2027         /*-
2028          * How to handle these functions?
2029          *      if (!tcp_is_cwnd_limited(sk, in_flight)) RRS - good question.
2030          *              return;
2031          */
2032         if (net->cwnd <= net->ssthresh) {
2033                 /* We are in slow start */
2034                 if (net->flight_size + net->net_ack >= net->cwnd) {
2035                         if (net->net_ack > (net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable))) {
2036                                 net->cwnd += (net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable));
2037                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2038                                         sctp_log_cwnd(stcb, net, net->mtu,
2039                                             SCTP_CWND_LOG_FROM_SS);
2040                                 }
2041                         } else {
2042                                 net->cwnd += net->net_ack;
2043                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2044                                         sctp_log_cwnd(stcb, net, net->net_ack,
2045                                             SCTP_CWND_LOG_FROM_SS);
2046                                 }
2047                         }
2048                 } else {
2049                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
2050                                 sctp_log_cwnd(stcb, net, net->net_ack,
2051                                     SCTP_CWND_LOG_NOADV_SS);
2052                         }
2053                 }
2054         } else {
2055                 measure_rtt(net);
2056
2057                 /*
2058                  * In dangerous area, increase slowly. In theory this is
2059                  * net->cwnd += alpha / net->cwnd
2060                  */
2061                 /* What is snd_cwnd_cnt?? */
2062                 if (((net->partial_bytes_acked / net->mtu * net->cc_mod.htcp_ca.alpha) >> 7) * net->mtu >= net->cwnd) {
2063                         /*-
2064                          * Does SCTP have a cwnd clamp?
2065                          * if (net->snd_cwnd < net->snd_cwnd_clamp) - Nope (RRS).
2066                          */
2067                         net->cwnd += net->mtu;
2068                         net->partial_bytes_acked = 0;
2069                         htcp_alpha_update(&net->cc_mod.htcp_ca);
2070                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2071                                 sctp_log_cwnd(stcb, net, net->mtu,
2072                                     SCTP_CWND_LOG_FROM_CA);
2073                         }
2074                 } else {
2075                         net->partial_bytes_acked += net->net_ack;
2076                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
2077                                 sctp_log_cwnd(stcb, net, net->net_ack,
2078                                     SCTP_CWND_LOG_NOADV_CA);
2079                         }
2080                 }
2081
2082                 net->cc_mod.htcp_ca.bytes_acked = net->mtu;
2083         }
2084 }
2085
2086 #ifdef SCTP_NOT_USED
2087 /* Lower bound on congestion window. */
2088 static uint32_t
2089 htcp_min_cwnd(struct sctp_tcb *stcb, struct sctp_nets *net)
2090 {
2091         return (net->ssthresh);
2092 }
2093
2094 #endif
2095
2096 static void
2097 htcp_init(struct sctp_nets *net)
2098 {
2099         memset(&net->cc_mod.htcp_ca, 0, sizeof(struct htcp));
2100         net->cc_mod.htcp_ca.alpha = ALPHA_BASE;
2101         net->cc_mod.htcp_ca.beta = BETA_MIN;
2102         net->cc_mod.htcp_ca.bytes_acked = net->mtu;
2103         net->cc_mod.htcp_ca.last_cong = sctp_get_tick_count();
2104 }
2105
2106 static void
2107 sctp_htcp_set_initial_cc_param(struct sctp_tcb *stcb, struct sctp_nets *net)
2108 {
2109         /*
2110          * We take the max of the burst limit times a MTU or the
2111          * INITIAL_CWND. We then limit this to 4 MTU's of sending.
2112          */
2113         net->cwnd = min((net->mtu * 4), max((2 * net->mtu), SCTP_INITIAL_CWND));
2114         net->ssthresh = stcb->asoc.peers_rwnd;
2115         htcp_init(net);
2116
2117         if (SCTP_BASE_SYSCTL(sctp_logging_level) & (SCTP_CWND_MONITOR_ENABLE | SCTP_CWND_LOGGING_ENABLE)) {
2118                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_INITIALIZATION);
2119         }
2120 }
2121
2122 static void
2123 sctp_htcp_cwnd_update_after_sack(struct sctp_tcb *stcb,
2124     struct sctp_association *asoc,
2125     int accum_moved, int reneged_all SCTP_UNUSED, int will_exit)
2126 {
2127         struct sctp_nets *net;
2128
2129         /******************************/
2130         /* update cwnd and Early FR   */
2131         /******************************/
2132         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
2133
2134 #ifdef JANA_CMT_FAST_RECOVERY
2135                 /*
2136                  * CMT fast recovery code. Need to debug.
2137                  */
2138                 if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
2139                         if (SCTP_TSN_GE(asoc->last_acked_seq, net->fast_recovery_tsn) ||
2140                             SCTP_TSN_GE(net->pseudo_cumack, net->fast_recovery_tsn)) {
2141                                 net->will_exit_fast_recovery = 1;
2142                         }
2143                 }
2144 #endif
2145                 /* if nothing was acked on this destination skip it */
2146                 if (net->net_ack == 0) {
2147                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
2148                                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
2149                         }
2150                         continue;
2151                 }
2152 #ifdef JANA_CMT_FAST_RECOVERY
2153                 /*
2154                  * CMT fast recovery code
2155                  */
2156                 /*
2157                  * if (sctp_cmt_on_off > 0 && net->fast_retran_loss_recovery
2158                  * && net->will_exit_fast_recovery == 0) { @@@ Do something
2159                  * } else if (sctp_cmt_on_off == 0 &&
2160                  * asoc->fast_retran_loss_recovery && will_exit == 0) {
2161                  */
2162 #endif
2163
2164                 if (asoc->fast_retran_loss_recovery &&
2165                     will_exit == 0 &&
2166                     (asoc->sctp_cmt_on_off == 0)) {
2167                         /*
2168                          * If we are in loss recovery we skip any cwnd
2169                          * update
2170                          */
2171                         return;
2172                 }
2173                 /*
2174                  * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
2175                  * moved.
2176                  */
2177                 if (accum_moved ||
2178                     ((asoc->sctp_cmt_on_off > 0) && net->new_pseudo_cumack)) {
2179                         htcp_cong_avoid(stcb, net);
2180                         measure_achieved_throughput(net);
2181                 } else {
2182                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
2183                                 sctp_log_cwnd(stcb, net, net->mtu,
2184                                     SCTP_CWND_LOG_NO_CUMACK);
2185                         }
2186                 }
2187         }
2188 }
2189
2190 static void
2191 sctp_htcp_cwnd_update_after_fr(struct sctp_tcb *stcb,
2192     struct sctp_association *asoc)
2193 {
2194         struct sctp_nets *net;
2195
2196         /*
2197          * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off > 0) &&
2198          * (net->fast_retran_loss_recovery == 0)))
2199          */
2200         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
2201                 if ((asoc->fast_retran_loss_recovery == 0) ||
2202                     (asoc->sctp_cmt_on_off > 0)) {
2203                         /* out of a RFC2582 Fast recovery window? */
2204                         if (net->net_ack > 0) {
2205                                 /*
2206                                  * per section 7.2.3, are there any
2207                                  * destinations that had a fast retransmit
2208                                  * to them. If so what we need to do is
2209                                  * adjust ssthresh and cwnd.
2210                                  */
2211                                 struct sctp_tmit_chunk *lchk;
2212                                 int old_cwnd = net->cwnd;
2213
2214                                 /* JRS - reset as if state were changed */
2215                                 htcp_reset(&net->cc_mod.htcp_ca);
2216                                 net->ssthresh = htcp_recalc_ssthresh(net);
2217                                 net->cwnd = net->ssthresh;
2218                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2219                                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
2220                                             SCTP_CWND_LOG_FROM_FR);
2221                                 }
2222                                 lchk = TAILQ_FIRST(&asoc->send_queue);
2223
2224                                 net->partial_bytes_acked = 0;
2225                                 /* Turn on fast recovery window */
2226                                 asoc->fast_retran_loss_recovery = 1;
2227                                 if (lchk == NULL) {
2228                                         /* Mark end of the window */
2229                                         asoc->fast_recovery_tsn = asoc->sending_seq - 1;
2230                                 } else {
2231                                         asoc->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
2232                                 }
2233
2234                                 /*
2235                                  * CMT fast recovery -- per destination
2236                                  * recovery variable.
2237                                  */
2238                                 net->fast_retran_loss_recovery = 1;
2239
2240                                 if (lchk == NULL) {
2241                                         /* Mark end of the window */
2242                                         net->fast_recovery_tsn = asoc->sending_seq - 1;
2243                                 } else {
2244                                         net->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
2245                                 }
2246
2247                                 sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
2248                                     stcb->sctp_ep, stcb, net, SCTP_FROM_SCTP_INDATA + SCTP_LOC_32);
2249                                 sctp_timer_start(SCTP_TIMER_TYPE_SEND,
2250                                     stcb->sctp_ep, stcb, net);
2251                         }
2252                 } else if (net->net_ack > 0) {
2253                         /*
2254                          * Mark a peg that we WOULD have done a cwnd
2255                          * reduction but RFC2582 prevented this action.
2256                          */
2257                         SCTP_STAT_INCR(sctps_fastretransinrtt);
2258                 }
2259         }
2260 }
2261
2262 static void
2263 sctp_htcp_cwnd_update_after_timeout(struct sctp_tcb *stcb,
2264     struct sctp_nets *net)
2265 {
2266         int old_cwnd = net->cwnd;
2267
2268         /* JRS - reset as if the state were being changed to timeout */
2269         htcp_reset(&net->cc_mod.htcp_ca);
2270         net->ssthresh = htcp_recalc_ssthresh(net);
2271         net->cwnd = net->mtu;
2272         net->partial_bytes_acked = 0;
2273         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2274                 sctp_log_cwnd(stcb, net, net->cwnd - old_cwnd, SCTP_CWND_LOG_FROM_RTX);
2275         }
2276 }
2277
2278 static void
2279 sctp_htcp_cwnd_update_after_ecn_echo(struct sctp_tcb *stcb,
2280     struct sctp_nets *net, int in_window, int num_pkt_lost SCTP_UNUSED)
2281 {
2282         int old_cwnd;
2283
2284         old_cwnd = net->cwnd;
2285
2286         /* JRS - reset hctp as if state changed */
2287         if (in_window == 0) {
2288                 htcp_reset(&net->cc_mod.htcp_ca);
2289                 SCTP_STAT_INCR(sctps_ecnereducedcwnd);
2290                 net->ssthresh = htcp_recalc_ssthresh(net);
2291                 if (net->ssthresh < net->mtu) {
2292                         net->ssthresh = net->mtu;
2293                         /* here back off the timer as well, to slow us down */
2294                         net->RTO <<= 1;
2295                 }
2296                 net->cwnd = net->ssthresh;
2297                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2298                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
2299                 }
2300         }
2301 }
2302
2303 struct sctp_cc_functions sctp_cc_functions[] = {
2304         {
2305                 .sctp_set_initial_cc_param = sctp_set_initial_cc_param,
2306                 .sctp_cwnd_update_after_sack = sctp_cwnd_update_after_sack,
2307                 .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
2308                 .sctp_cwnd_update_after_fr = sctp_cwnd_update_after_fr,
2309                 .sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
2310                 .sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_after_ecn_echo,
2311                 .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
2312                 .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
2313         },
2314         {
2315                 .sctp_set_initial_cc_param = sctp_set_initial_cc_param,
2316                 .sctp_cwnd_update_after_sack = sctp_hs_cwnd_update_after_sack,
2317                 .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
2318                 .sctp_cwnd_update_after_fr = sctp_hs_cwnd_update_after_fr,
2319                 .sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
2320                 .sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_after_ecn_echo,
2321                 .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
2322                 .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
2323         },
2324         {
2325                 .sctp_set_initial_cc_param = sctp_htcp_set_initial_cc_param,
2326                 .sctp_cwnd_update_after_sack = sctp_htcp_cwnd_update_after_sack,
2327                 .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
2328                 .sctp_cwnd_update_after_fr = sctp_htcp_cwnd_update_after_fr,
2329                 .sctp_cwnd_update_after_timeout = sctp_htcp_cwnd_update_after_timeout,
2330                 .sctp_cwnd_update_after_ecn_echo = sctp_htcp_cwnd_update_after_ecn_echo,
2331                 .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
2332                 .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
2333         },
2334         {
2335                 .sctp_set_initial_cc_param = sctp_set_rtcc_initial_cc_param,
2336                 .sctp_cwnd_update_after_sack = sctp_cwnd_update_rtcc_after_sack,
2337                 .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
2338                 .sctp_cwnd_update_after_fr = sctp_cwnd_update_after_fr,
2339                 .sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
2340                 .sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_rtcc_after_ecn_echo,
2341                 .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
2342                 .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
2343                 .sctp_cwnd_update_packet_transmitted = sctp_cwnd_update_rtcc_packet_transmitted,
2344                 .sctp_cwnd_update_tsn_acknowledged = sctp_cwnd_update_rtcc_tsn_acknowledged,
2345                 .sctp_cwnd_new_transmission_begins = sctp_cwnd_new_rtcc_transmission_begins,
2346                 .sctp_cwnd_prepare_net_for_sack = sctp_cwnd_prepare_rtcc_net_for_sack,
2347                 .sctp_cwnd_socket_option = sctp_cwnd_rtcc_socket_option,
2348                 .sctp_rtt_calculated = sctp_rtt_rtcc_calculated
2349         }
2350 };