src/third_party/usrsctp/usrsctplib/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 #ifdef __FreeBSD__
  34 #include <sys/cdefs.h>
  35 __FBSDID("$FreeBSD: head/sys/netinet/sctp_cc_functions.c 271672 2014-09-16 13:48:46Z tuexen $");
  36 #endif
  37
  38 #include <netinet/sctp_os.h>
  39 #include <netinet/sctp_var.h>
  40 #include <netinet/sctp_sysctl.h>
  41 #include <netinet/sctp_pcb.h>
  42 #include <netinet/sctp_header.h>
  43 #include <netinet/sctputil.h>
  44 #include <netinet/sctp_output.h>
  45 #include <netinet/sctp_input.h>
  46 #include <netinet/sctp_indata.h>
  47 #include <netinet/sctp_uio.h>
  48 #include <netinet/sctp_timer.h>
  49 #include <netinet/sctp_auth.h>
  50 #include <netinet/sctp_asconf.h>
  51 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
  52 #include <netinet/sctp_dtrace_declare.h>
  53 #endif
  54
  55 #define SHIFT_MPTCP_MULTI_N 40
  56 #define SHIFT_MPTCP_MULTI_Z 16
  57 #define SHIFT_MPTCP_MULTI 8
  58
  59 static void
  60 sctp_set_initial_cc_param(struct sctp_tcb *stcb, struct sctp_nets *net)
  61 {
  62         struct sctp_association *assoc;
  63         uint32_t cwnd_in_mtu;
  64
  65         assoc = &stcb->asoc;
  66         cwnd_in_mtu = SCTP_BASE_SYSCTL(sctp_initial_cwnd);
  67         if (cwnd_in_mtu == 0) {
  68                 /* Using 0 means that the value of RFC 4960 is used. */
  69                 net->cwnd = min((net->mtu * 4), max((2 * net->mtu), SCTP_INITIAL_CWND));
  70         } else {
  71                 /*
  72                  * We take the minimum of the burst limit and the
  73                  * initial congestion window.
  74                  */
  75                 if ((assoc->max_burst > 0) && (cwnd_in_mtu > assoc->max_burst))
  76                         cwnd_in_mtu = assoc->max_burst;
  77                 net->cwnd = (net->mtu - sizeof(struct sctphdr)) * cwnd_in_mtu;
  78         }
  79         if ((stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) ||
  80             (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV2)) {
  81                 /* In case of resource pooling initialize appropriately */
  82                 net->cwnd /= assoc->numnets;
  83                 if (net->cwnd < (net->mtu - sizeof(struct sctphdr))) {
  84                         net->cwnd = net->mtu - sizeof(struct sctphdr);
  85                 }
  86         }
  87         net->ssthresh = assoc->peers_rwnd;
  88 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
  89         SDT_PROBE(sctp, cwnd, net, init,
  90                   stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
  91                   0, net->cwnd);
  92 #endif
  93         if (SCTP_BASE_SYSCTL(sctp_logging_level) &
  94             (SCTP_CWND_MONITOR_ENABLE|SCTP_CWND_LOGGING_ENABLE)) {
  95                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_INITIALIZATION);
  96         }
  97 }
  98
  99 static void
 100 sctp_cwnd_update_after_fr(struct sctp_tcb *stcb,
 101                           struct sctp_association *asoc)
 102 {
 103         struct sctp_nets *net;
 104         uint32_t t_ssthresh, t_cwnd;
 105         uint64_t t_ucwnd_sbw;
 106
 107         /* MT FIXME: Don't compute this over and over again */
 108         t_ssthresh = 0;
 109         t_cwnd = 0;
 110         t_ucwnd_sbw = 0;
 111         if ((asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) ||
 112             (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2)) {
 113                 TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
 114                         t_ssthresh += net->ssthresh;
 115                         t_cwnd += net->cwnd;
 116                         if (net->lastsa > 0) {
 117                                 t_ucwnd_sbw += (uint64_t)net->cwnd / (uint64_t)net->lastsa;
 118                         }
 119                 }
 120                 if (t_ucwnd_sbw == 0) {
 121                         t_ucwnd_sbw = 1;
 122                 }
 123         }
 124
 125         /*-
 126          * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off > 0) &&
 127          * (net->fast_retran_loss_recovery == 0)))
 128          */
 129         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
 130                 if ((asoc->fast_retran_loss_recovery == 0) ||
 131                     (asoc->sctp_cmt_on_off > 0)) {
 132                         /* out of a RFC2582 Fast recovery window? */
 133                         if (net->net_ack > 0) {
 134                                 /*
 135                                  * per section 7.2.3, are there any
 136                                  * destinations that had a fast retransmit
 137                                  * to them. If so what we need to do is
 138                                  * adjust ssthresh and cwnd.
 139                                  */
 140                                 struct sctp_tmit_chunk *lchk;
 141                                 int old_cwnd = net->cwnd;
 142
 143                                 if ((asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) ||
 144                                     (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2)) {
 145                                         if (asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) {
 146                                                 net->ssthresh = (uint32_t)(((uint64_t)4 *
 147                                                                             (uint64_t)net->mtu *
 148                                                                             (uint64_t)net->ssthresh) /
 149                                                                            (uint64_t)t_ssthresh);
 150
 151                                         }
 152                                         if (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2) {
 153                                                 uint32_t srtt;
 154
 155                                                 srtt = net->lastsa;
 156                                                 /* lastsa>>3;  we don't need to devide ...*/
 157                                                 if (srtt == 0) {
 158                                                         srtt = 1;
 159                                                 }
 160                                                 /* Short Version => Equal to Contel Version MBe */
 161                                                 net->ssthresh = (uint32_t) (((uint64_t)4 *
 162                                                                              (uint64_t)net->mtu *
 163                                                                              (uint64_t)net->cwnd) /
 164                                                                             ((uint64_t)srtt *
 165                                                                              t_ucwnd_sbw));
 166                                                                              /* INCREASE FACTOR */;
 167                                         }
 168                                         if ((net->cwnd > t_cwnd / 2) &&
 169                                             (net->ssthresh < net->cwnd - t_cwnd / 2)) {
 170                                                 net->ssthresh = net->cwnd - t_cwnd / 2;
 171                                         }
 172                                         if (net->ssthresh < net->mtu) {
 173                                                 net->ssthresh = net->mtu;
 174                                         }
 175                                 } else {
 176                                         net->ssthresh = net->cwnd / 2;
 177                                         if (net->ssthresh < (net->mtu * 2)) {
 178                                                 net->ssthresh = 2 * net->mtu;
 179                                         }
 180                                 }
 181                                 net->cwnd = net->ssthresh;
 182 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 183                                 SDT_PROBE(sctp, cwnd, net, fr,
 184                                           stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
 185                                           old_cwnd, net->cwnd);
 186 #endif
 187                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 188                                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
 189                                                 SCTP_CWND_LOG_FROM_FR);
 190                                 }
 191                                 lchk = TAILQ_FIRST(&asoc->send_queue);
 192
 193                                 net->partial_bytes_acked = 0;
 194                                 /* Turn on fast recovery window */
 195                                 asoc->fast_retran_loss_recovery = 1;
 196                                 if (lchk == NULL) {
 197                                         /* Mark end of the window */
 198                                         asoc->fast_recovery_tsn = asoc->sending_seq - 1;
 199                                 } else {
 200                                         asoc->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
 201                                 }
 202
 203                                 /*
 204                                  * CMT fast recovery -- per destination
 205                                  * recovery variable.
 206                                  */
 207                                 net->fast_retran_loss_recovery = 1;
 208
 209                                 if (lchk == NULL) {
 210                                         /* Mark end of the window */
 211                                         net->fast_recovery_tsn = asoc->sending_seq - 1;
 212                                 } else {
 213                                         net->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
 214                                 }
 215
 216                                 sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
 217                                                 stcb->sctp_ep, stcb, net, SCTP_FROM_SCTP_INDATA+SCTP_LOC_32 );
 218                                 sctp_timer_start(SCTP_TIMER_TYPE_SEND,
 219                                                  stcb->sctp_ep, stcb, net);
 220                         }
 221                 } else if (net->net_ack > 0) {
 222                         /*
 223                          * Mark a peg that we WOULD have done a cwnd
 224                          * reduction but RFC2582 prevented this action.
 225                          */
 226                         SCTP_STAT_INCR(sctps_fastretransinrtt);
 227                 }
 228         }
 229 }
 230
 231 /* Defines for instantaneous bw decisions */
 232 #define SCTP_INST_LOOSING 1 /* Loosing to other flows */
 233 #define SCTP_INST_NEUTRAL 2 /* Neutral, no indication */
 234 #define SCTP_INST_GAINING 3 /* Gaining, step down possible */
 235
 236
 237 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 238 static int
 239 cc_bw_same(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw,
 240            uint64_t rtt_offset, uint64_t vtag, uint8_t inst_ind)
 241 #else
 242 static int
 243 cc_bw_same(struct sctp_tcb *stcb SCTP_UNUSED, struct sctp_nets *net, uint64_t nbw,
 244            uint64_t rtt_offset, uint8_t inst_ind)
 245 #endif
 246 {
 247 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 248         uint64_t oth, probepoint;
 249 #endif
 250
 251 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 252         probepoint = (((uint64_t)net->cwnd) << 32);
 253 #endif
 254         if (net->rtt > net->cc_mod.rtcc.lbw_rtt + rtt_offset) {
 255                 /*
 256                  * rtt increased
 257                  * we don't update bw.. so we don't
 258                  * update the rtt either.
 259                  */
 260 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 261                 /* Probe point 5 */
 262                 probepoint |=  ((5 << 16) | 1);
 263                 SDT_PROBE(sctp, cwnd, net, rttvar,
 264                           vtag,
 265                           ((net->cc_mod.rtcc.lbw << 32) | nbw),
 266                           ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 267                           net->flight_size,
 268                           probepoint);
 269 #endif
 270                 if ((net->cc_mod.rtcc.steady_step) && (inst_ind != SCTP_INST_LOOSING)) {
 271                         if (net->cc_mod.rtcc.last_step_state == 5)
 272                                 net->cc_mod.rtcc.step_cnt++;
 273                         else
 274                                 net->cc_mod.rtcc.step_cnt = 1;
 275                         net->cc_mod.rtcc.last_step_state = 5;
 276                         if ((net->cc_mod.rtcc.step_cnt == net->cc_mod.rtcc.steady_step) ||
 277                             ((net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step) &&
 278                              ((net->cc_mod.rtcc.step_cnt % net->cc_mod.rtcc.steady_step) == 0))) {
 279                                 /* Try a step down */
 280 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 281                                 oth = net->cc_mod.rtcc.vol_reduce;
 282                                 oth <<= 16;
 283                                 oth |= net->cc_mod.rtcc.step_cnt;
 284                                 oth <<= 16;
 285                                 oth |= net->cc_mod.rtcc.last_step_state;
 286                                 SDT_PROBE(sctp, cwnd, net, rttstep,
 287                                           vtag,
 288                                           ((net->cc_mod.rtcc.lbw << 32) | nbw),
 289                                           ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 290                                           oth,
 291                                           probepoint);
 292 #endif
 293                                 if (net->cwnd > (4 * net->mtu)) {
 294                                         net->cwnd -= net->mtu;
 295                                         net->cc_mod.rtcc.vol_reduce++;
 296                                 } else {
 297                                         net->cc_mod.rtcc.step_cnt = 0;
 298                                 }
 299                         }
 300                 }
 301                 return (1);
 302         }
 303         if (net->rtt  < net->cc_mod.rtcc.lbw_rtt-rtt_offset) {
 304                 /*
 305                  * rtt decreased, there could be more room.
 306                  * we update both the bw and the rtt here to
 307                  * lock this in as a good step down.
 308                  */
 309 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 310                 /* Probe point 6 */
 311                 probepoint |=  ((6 << 16) | 0);
 312                 SDT_PROBE(sctp, cwnd, net, rttvar,
 313                           vtag,
 314                           ((net->cc_mod.rtcc.lbw << 32) | nbw),
 315                           ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 316                           net->flight_size,
 317                           probepoint);
 318 #endif
 319                 if (net->cc_mod.rtcc.steady_step) {
 320 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 321                         oth = net->cc_mod.rtcc.vol_reduce;
 322                         oth <<= 16;
 323                         oth |= net->cc_mod.rtcc.step_cnt;
 324                         oth <<= 16;
 325                         oth |= net->cc_mod.rtcc.last_step_state;
 326                         SDT_PROBE(sctp, cwnd, net, rttstep,
 327                                   vtag,
 328                                   ((net->cc_mod.rtcc.lbw << 32) | nbw),
 329                                   ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 330                                   oth,
 331                                   probepoint);
 332 #endif
 333                         if ((net->cc_mod.rtcc.last_step_state == 5) &&
 334                             (net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step)) {
 335                                 /* Step down worked */
 336                                 net->cc_mod.rtcc.step_cnt = 0;
 337                                 return (1);
 338                         } else {
 339                                 net->cc_mod.rtcc.last_step_state = 6;
 340                                 net->cc_mod.rtcc.step_cnt = 0;
 341                         }
 342                 }
 343                 net->cc_mod.rtcc.lbw = nbw;
 344                 net->cc_mod.rtcc.lbw_rtt = net->rtt;
 345                 net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
 346                 if (inst_ind == SCTP_INST_GAINING)
 347                         return (1);
 348                 else if (inst_ind == SCTP_INST_NEUTRAL)
 349                         return (1);
 350                 else
 351                         return (0);
 352         }
 353         /* Ok bw and rtt remained the same .. no update to any
 354          */
 355 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 356         /* Probe point 7 */
 357         probepoint |=  ((7 << 16) | net->cc_mod.rtcc.ret_from_eq);
 358         SDT_PROBE(sctp, cwnd, net, rttvar,
 359                   vtag,
 360                   ((net->cc_mod.rtcc.lbw << 32) | nbw),
 361                   ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 362                   net->flight_size,
 363                   probepoint);
 364 #endif
 365         if ((net->cc_mod.rtcc.steady_step) && (inst_ind != SCTP_INST_LOOSING)) {
 366                 if (net->cc_mod.rtcc.last_step_state == 5)
 367                         net->cc_mod.rtcc.step_cnt++;
 368                 else
 369                         net->cc_mod.rtcc.step_cnt = 1;
 370                 net->cc_mod.rtcc.last_step_state = 5;
 371                 if ((net->cc_mod.rtcc.step_cnt == net->cc_mod.rtcc.steady_step) ||
 372                     ((net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step) &&
 373                      ((net->cc_mod.rtcc.step_cnt % net->cc_mod.rtcc.steady_step) == 0))) {
 374                         /* Try a step down */
 375                         if (net->cwnd > (4 * net->mtu)) {
 376                                 net->cwnd -= net->mtu;
 377                                 net->cc_mod.rtcc.vol_reduce++;
 378                                 return (1);
 379                         } else {
 380                                 net->cc_mod.rtcc.step_cnt = 0;
 381                         }
 382                 }
 383         }
 384         if (inst_ind == SCTP_INST_GAINING)
 385                 return (1);
 386         else if (inst_ind == SCTP_INST_NEUTRAL)
 387                 return (1);
 388         else
 389                 return ((int)net->cc_mod.rtcc.ret_from_eq);
 390 }
 391
 392 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 393 static int
 394 cc_bw_decrease(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw, uint64_t rtt_offset,
 395                uint64_t vtag, uint8_t inst_ind)
 396 #else
 397 static int
 398 cc_bw_decrease(struct sctp_tcb *stcb SCTP_UNUSED, struct sctp_nets *net, uint64_t nbw, uint64_t rtt_offset,
 399                uint8_t inst_ind)
 400 #endif
 401 {
 402 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 403         uint64_t oth, probepoint;
 404 #endif
 405
 406         /* Bandwidth decreased.*/
 407 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 408         probepoint = (((uint64_t)net->cwnd) << 32);
 409 #endif
 410         if (net->rtt  > net->cc_mod.rtcc.lbw_rtt+rtt_offset) {
 411                 /* rtt increased */
 412                 /* Did we add more */
 413                 if ((net->cwnd > net->cc_mod.rtcc.cwnd_at_bw_set) &&
 414                     (inst_ind != SCTP_INST_LOOSING)) {
 415                         /* We caused it maybe.. back off? */
 416 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 417                         /* PROBE POINT 1 */
 418                         probepoint |=  ((1 << 16) | 1);
 419                         SDT_PROBE(sctp, cwnd, net, rttvar,
 420                                   vtag,
 421                                   ((net->cc_mod.rtcc.lbw << 32) | nbw),
 422                                   ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 423                                   net->flight_size,
 424                                   probepoint);
 425 #endif
 426                         if (net->cc_mod.rtcc.ret_from_eq) {
 427                                 /* Switch over to CA if we are less aggressive */
 428                                 net->ssthresh = net->cwnd-1;
 429                                 net->partial_bytes_acked = 0;
 430                         }
 431                         return (1);
 432                 }
 433 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 434                 /* Probe point 2 */
 435                 probepoint |=  ((2 << 16) | 0);
 436                 SDT_PROBE(sctp, cwnd, net, rttvar,
 437                           vtag,
 438                           ((net->cc_mod.rtcc.lbw << 32) | nbw),
 439                           ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 440                           net->flight_size,
 441                           probepoint);
 442 #endif
 443                 /* Someone else - fight for more? */
 444                 if (net->cc_mod.rtcc.steady_step) {
 445 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 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 #endif
 458                         /* Did we voluntarily give up some? if so take
 459                          * one back please
 460                          */
 461                         if ((net->cc_mod.rtcc.vol_reduce) &&
 462                             (inst_ind != SCTP_INST_GAINING)) {
 463                                 net->cwnd += net->mtu;
 464                                 net->cc_mod.rtcc.vol_reduce--;
 465                         }
 466                         net->cc_mod.rtcc.last_step_state = 2;
 467                         net->cc_mod.rtcc.step_cnt = 0;
 468                 }
 469                 goto out_decision;
 470         } else  if (net->rtt  < net->cc_mod.rtcc.lbw_rtt-rtt_offset) {
 471                 /* bw & rtt decreased */
 472 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 473                 /* Probe point 3 */
 474                 probepoint |=  ((3 << 16) | 0);
 475                 SDT_PROBE(sctp, cwnd, net, rttvar,
 476                           vtag,
 477                           ((net->cc_mod.rtcc.lbw << 32) | nbw),
 478                           ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 479                           net->flight_size,
 480                           probepoint);
 481 #endif
 482                 if (net->cc_mod.rtcc.steady_step) {
 483 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 484                         oth = net->cc_mod.rtcc.vol_reduce;
 485                         oth <<= 16;
 486                         oth |= net->cc_mod.rtcc.step_cnt;
 487                         oth <<= 16;
 488                         oth |= net->cc_mod.rtcc.last_step_state;
 489                         SDT_PROBE(sctp, cwnd, net, rttstep,
 490                                   vtag,
 491                                   ((net->cc_mod.rtcc.lbw << 32) | nbw),
 492                                   ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 493                                   oth,
 494                                   probepoint);
 495 #endif
 496                         if ((net->cc_mod.rtcc.vol_reduce) &&
 497                             (inst_ind != SCTP_INST_GAINING)) {
 498                                 net->cwnd += net->mtu;
 499                                 net->cc_mod.rtcc.vol_reduce--;
 500                         }
 501                         net->cc_mod.rtcc.last_step_state = 3;
 502                         net->cc_mod.rtcc.step_cnt = 0;
 503                 }
 504                 goto out_decision;
 505         }
 506         /* The bw decreased but rtt stayed the same */
 507 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 508         /* Probe point 4 */
 509         probepoint |=  ((4 << 16) | 0);
 510         SDT_PROBE(sctp, cwnd, net, rttvar,
 511                   vtag,
 512                   ((net->cc_mod.rtcc.lbw << 32) | nbw),
 513                   ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 514                   net->flight_size,
 515                   probepoint);
 516 #endif
 517         if (net->cc_mod.rtcc.steady_step) {
 518 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 519                 oth = net->cc_mod.rtcc.vol_reduce;
 520                 oth <<= 16;
 521                 oth |= net->cc_mod.rtcc.step_cnt;
 522                 oth <<= 16;
 523                 oth |= net->cc_mod.rtcc.last_step_state;
 524                 SDT_PROBE(sctp, cwnd, net, rttstep,
 525                           vtag,
 526                           ((net->cc_mod.rtcc.lbw << 32) | nbw),
 527                           ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 528                           oth,
 529                           probepoint);
 530 #endif
 531                 if ((net->cc_mod.rtcc.vol_reduce) &&
 532                     (inst_ind != SCTP_INST_GAINING)) {
 533                         net->cwnd += net->mtu;
 534                         net->cc_mod.rtcc.vol_reduce--;
 535                 }
 536                 net->cc_mod.rtcc.last_step_state = 4;
 537                 net->cc_mod.rtcc.step_cnt = 0;
 538         }
 539 out_decision:
 540         net->cc_mod.rtcc.lbw = nbw;
 541         net->cc_mod.rtcc.lbw_rtt = net->rtt;
 542         net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
 543         if (inst_ind == SCTP_INST_GAINING) {
 544                 return (1);
 545         } else {
 546                 return (0);
 547         }
 548 }
 549
 550 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 551 static int
 552 cc_bw_increase(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw, uint64_t vtag)
 553 #else
 554 static int
 555 cc_bw_increase(struct sctp_tcb *stcb SCTP_UNUSED, struct sctp_nets *net, uint64_t nbw)
 556 #endif
 557 {
 558 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 559         uint64_t oth, probepoint;
 560
 561 #endif
 562         /* BW increased, so update and
 563          * return 0, since all actions in
 564          * our table say to do the normal CC
 565          * update. Note that we pay no attention to
 566          * the inst_ind since our overall sum is increasing.
 567          */
 568 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 569         /* PROBE POINT 0 */
 570         probepoint = (((uint64_t)net->cwnd) << 32);
 571         SDT_PROBE(sctp, cwnd, net, rttvar,
 572                   vtag,
 573                   ((net->cc_mod.rtcc.lbw << 32) | nbw),
 574                   ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 575                   net->flight_size,
 576                   probepoint);
 577 #endif
 578         if (net->cc_mod.rtcc.steady_step) {
 579 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 580                 oth = net->cc_mod.rtcc.vol_reduce;
 581                 oth <<= 16;
 582                 oth |= net->cc_mod.rtcc.step_cnt;
 583                 oth <<= 16;
 584                 oth |= net->cc_mod.rtcc.last_step_state;
 585                 SDT_PROBE(sctp, cwnd, net, rttstep,
 586                           vtag,
 587                           ((net->cc_mod.rtcc.lbw << 32) | nbw),
 588                           ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 589                           oth,
 590                           probepoint);
 591 #endif
 592                 net->cc_mod.rtcc.last_step_state = 0;
 593                 net->cc_mod.rtcc.step_cnt = 0;
 594                 net->cc_mod.rtcc.vol_reduce = 0;
 595         }
 596         net->cc_mod.rtcc.lbw = nbw;
 597         net->cc_mod.rtcc.lbw_rtt = net->rtt;
 598         net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
 599         return (0);
 600 }
 601
 602 /* RTCC Algoritm to limit growth of cwnd, return
 603  * true if you want to NOT allow cwnd growth
 604  */
 605 static int
 606 cc_bw_limit(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw)
 607 {
 608         uint64_t bw_offset, rtt_offset;
 609 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 610         uint64_t probepoint, rtt, vtag;
 611 #endif
 612         uint64_t bytes_for_this_rtt, inst_bw;
 613         uint64_t div, inst_off;
 614         int bw_shift;
 615         uint8_t inst_ind;
 616         int ret;
 617         /*-
 618          * Here we need to see if we want
 619          * to limit cwnd growth due to increase
 620          * in overall rtt but no increase in bw.
 621          * We use the following table to figure
 622          * out what we should do. When we return
 623          * 0, cc update goes on as planned. If we
 624          * return 1, then no cc update happens and cwnd
 625          * stays where it is at.
 626          * ----------------------------------
 627          *   BW    |    RTT   | Action
 628          * *********************************
 629          *   INC   |    INC   | return 0
 630          * ----------------------------------
 631          *   INC   |    SAME  | return 0
 632          * ----------------------------------
 633          *   INC   |    DECR  | return 0
 634          * ----------------------------------
 635          *   SAME  |    INC   | return 1
 636          * ----------------------------------
 637          *   SAME  |    SAME  | return 1
 638          * ----------------------------------
 639          *   SAME  |    DECR  | return 0
 640          * ----------------------------------
 641          *   DECR  |    INC   | return 0 or 1 based on if we caused.
 642          * ----------------------------------
 643          *   DECR  |    SAME  | return 0
 644          * ----------------------------------
 645          *   DECR  |    DECR  | return 0
 646          * ----------------------------------
 647          *
 648          * We are a bit fuzz on what an increase or
 649          * decrease is. For BW it is the same if
 650          * it did not change within 1/64th. For
 651          * RTT it stayed the same if it did not
 652          * change within 1/32nd
 653          */
 654         bw_shift = SCTP_BASE_SYSCTL(sctp_rttvar_bw);
 655 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 656         rtt = stcb->asoc.my_vtag;
 657         vtag = (rtt << 32) | (((uint32_t)(stcb->sctp_ep->sctp_lport)) << 16) | (stcb->rport);
 658         probepoint = (((uint64_t)net->cwnd) << 32);
 659         rtt = net->rtt;
 660 #endif
 661         if (net->cc_mod.rtcc.rtt_set_this_sack) {
 662                 net->cc_mod.rtcc.rtt_set_this_sack = 0;
 663                 bytes_for_this_rtt = net->cc_mod.rtcc.bw_bytes - net->cc_mod.rtcc.bw_bytes_at_last_rttc;
 664                 net->cc_mod.rtcc.bw_bytes_at_last_rttc = net->cc_mod.rtcc.bw_bytes;
 665                 if (net->rtt) {
 666                         div = net->rtt / 1000;
 667                         if (div) {
 668                                 inst_bw = bytes_for_this_rtt / div;
 669                                 inst_off = inst_bw >> bw_shift;
 670                                 if (inst_bw > nbw)
 671                                         inst_ind = SCTP_INST_GAINING;
 672                                 else if ((inst_bw+inst_off) < nbw)
 673                                         inst_ind = SCTP_INST_LOOSING;
 674                                 else
 675                                         inst_ind = SCTP_INST_NEUTRAL;
 676 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 677                                 probepoint |=  ((0xb << 16) | inst_ind);
 678 #endif
 679                         } else {
 680                                 inst_ind = net->cc_mod.rtcc.last_inst_ind;
 681 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 682                                 inst_bw = bytes_for_this_rtt / (uint64_t)(net->rtt);
 683                                 /* Can't determine do not change */
 684                                 probepoint |=  ((0xc << 16) | inst_ind);
 685 #endif
 686                         }
 687                 } else {
 688                         inst_ind = net->cc_mod.rtcc.last_inst_ind;
 689 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 690                         inst_bw = bytes_for_this_rtt;
 691                         /* Can't determine do not change */
 692                         probepoint |=  ((0xd << 16) | inst_ind);
 693 #endif
 694                 }
 695 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 696                 SDT_PROBE(sctp, cwnd, net, rttvar,
 697                           vtag,
 698                           ((nbw << 32) | inst_bw),
 699                           ((net->cc_mod.rtcc.lbw_rtt << 32) | rtt),
 700                           net->flight_size,
 701                           probepoint);
 702 #endif
 703         } else {
 704                 /* No rtt measurement, use last one */
 705                 inst_ind = net->cc_mod.rtcc.last_inst_ind;
 706         }
 707         bw_offset = net->cc_mod.rtcc.lbw >> bw_shift;
 708         if (nbw > net->cc_mod.rtcc.lbw + bw_offset) {
 709 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 710                 ret = cc_bw_increase(stcb, net, nbw, vtag);
 711 #else
 712                 ret = cc_bw_increase(stcb, net, nbw);
 713 #endif
 714                 goto out;
 715         }
 716         rtt_offset = net->cc_mod.rtcc.lbw_rtt >> SCTP_BASE_SYSCTL(sctp_rttvar_rtt);
 717         if (nbw < net->cc_mod.rtcc.lbw - bw_offset) {
 718 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 719                 ret = cc_bw_decrease(stcb, net, nbw, rtt_offset, vtag, inst_ind);
 720 #else
 721                 ret = cc_bw_decrease(stcb, net, nbw, rtt_offset, inst_ind);
 722 #endif
 723                 goto out;
 724         }
 725         /* If we reach here then
 726          * we are in a situation where
 727          * the bw stayed the same.
 728          */
 729 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 730         ret = cc_bw_same(stcb, net, nbw, rtt_offset, vtag, inst_ind);
 731 #else
 732         ret = cc_bw_same(stcb, net, nbw, rtt_offset, inst_ind);
 733 #endif
 734 out:
 735         net->cc_mod.rtcc.last_inst_ind = inst_ind;
 736         return (ret);
 737 }
 738
 739 static void
 740 sctp_cwnd_update_after_sack_common(struct sctp_tcb *stcb,
 741                                    struct sctp_association *asoc,
 742                                    int accum_moved, int reneged_all SCTP_UNUSED, int will_exit, int use_rtcc)
 743 {
 744         struct sctp_nets *net;
 745 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 746         int old_cwnd;
 747 #endif
 748         uint32_t t_ssthresh, t_cwnd, incr;
 749         uint64_t t_ucwnd_sbw;
 750         uint64_t t_path_mptcp;
 751         uint64_t mptcp_like_alpha;
 752         uint32_t srtt;
 753         uint64_t max_path;
 754
 755         /* MT FIXME: Don't compute this over and over again */
 756         t_ssthresh = 0;
 757         t_cwnd = 0;
 758         t_ucwnd_sbw = 0;
 759         t_path_mptcp = 0;
 760         mptcp_like_alpha = 1;
 761         if ((stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) ||
 762             (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV2) ||
 763             (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_MPTCP)) {
 764                 max_path = 0;
 765                 TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
 766                         t_ssthresh += net->ssthresh;
 767                         t_cwnd += net->cwnd;
 768                         /* lastsa>>3;  we don't need to devide ...*/
 769                         srtt = net->lastsa;
 770                         if (srtt > 0) {
 771                                 uint64_t tmp;
 772
 773                                 t_ucwnd_sbw += (uint64_t)net->cwnd / (uint64_t)srtt;
 774                                 t_path_mptcp += (((uint64_t)net->cwnd) << SHIFT_MPTCP_MULTI_Z) /
 775                                                 (((uint64_t)net->mtu) * (uint64_t)srtt);
 776                                 tmp = (((uint64_t)net->cwnd) << SHIFT_MPTCP_MULTI_N) /
 777                                       ((uint64_t)net->mtu * (uint64_t)(srtt * srtt));
 778                                 if (tmp > max_path) {
 779                                         max_path = tmp;
 780                                 }
 781                         }
 782                 }
 783                 if (t_path_mptcp > 0) {
 784                         mptcp_like_alpha = max_path / (t_path_mptcp * t_path_mptcp);
 785                 } else {
 786                         mptcp_like_alpha = 1;
 787                 }
 788         }
 789         if (t_ssthresh == 0) {
 790                 t_ssthresh = 1;
 791         }
 792         if (t_ucwnd_sbw == 0) {
 793                 t_ucwnd_sbw = 1;
 794         }
 795         /******************************/
 796         /* update cwnd and Early FR   */
 797         /******************************/
 798         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
 799
 800 #ifdef JANA_CMT_FAST_RECOVERY
 801                 /*
 802                  * CMT fast recovery code. Need to debug.
 803                  */
 804                 if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
 805                         if (SCTP_TSN_GE(asoc->last_acked_seq, net->fast_recovery_tsn) ||
 806                             SCTP_TSN_GE(net->pseudo_cumack,net->fast_recovery_tsn)) {
 807                                 net->will_exit_fast_recovery = 1;
 808                         }
 809                 }
 810 #endif
 811                 /* if nothing was acked on this destination skip it */
 812                 if (net->net_ack == 0) {
 813                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 814                                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
 815                         }
 816                         continue;
 817                 }
 818 #ifdef JANA_CMT_FAST_RECOVERY
 819                 /* CMT fast recovery code
 820                  */
 821                 /*
 822                   if (sctp_cmt_on_off > 0 && net->fast_retran_loss_recovery && net->will_exit_fast_recovery == 0) {
 823                   @@@ Do something
 824                   }
 825                   else if (sctp_cmt_on_off == 0 && asoc->fast_retran_loss_recovery && will_exit == 0) {
 826                 */
 827 #endif
 828
 829                 if (asoc->fast_retran_loss_recovery &&
 830                     (will_exit == 0) &&
 831                     (asoc->sctp_cmt_on_off == 0)) {
 832                         /*
 833                          * If we are in loss recovery we skip any cwnd
 834                          * update
 835                          */
 836                         return;
 837                 }
 838                 /*
 839                  * Did any measurements go on for this network?
 840                  */
 841                 if (use_rtcc && (net->cc_mod.rtcc.tls_needs_set > 0)) {
 842                         uint64_t nbw;
 843                         /*
 844                          * At this point our bw_bytes has been updated
 845                          * by incoming sack information.
 846                          *
 847                          * But our bw may not yet be set.
 848                          *
 849                          */
 850                         if ((net->cc_mod.rtcc.new_tot_time/1000) > 0) {
 851                                 nbw = net->cc_mod.rtcc.bw_bytes/(net->cc_mod.rtcc.new_tot_time/1000);
 852                         } else {
 853                                 nbw = net->cc_mod.rtcc.bw_bytes;
 854                         }
 855                         if (net->cc_mod.rtcc.lbw) {
 856                                 if (cc_bw_limit(stcb, net, nbw)) {
 857                                         /* Hold here, no update */
 858                                         continue;
 859                                 }
 860                         } else {
 861 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 862                                 uint64_t vtag, probepoint;
 863
 864                                 probepoint = (((uint64_t)net->cwnd) << 32);
 865                                 probepoint |=  ((0xa << 16) | 0);
 866                                 vtag = (net->rtt << 32) |
 867                                         (((uint32_t)(stcb->sctp_ep->sctp_lport)) << 16) |
 868                                         (stcb->rport);
 869
 870                                 SDT_PROBE(sctp, cwnd, net, rttvar,
 871                                           vtag,
 872                                           nbw,
 873                                           ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 874                                           net->flight_size,
 875                                           probepoint);
 876 #endif
 877                                 net->cc_mod.rtcc.lbw = nbw;
 878                                 net->cc_mod.rtcc.lbw_rtt = net->rtt;
 879                                 if (net->cc_mod.rtcc.rtt_set_this_sack) {
 880                                         net->cc_mod.rtcc.rtt_set_this_sack = 0;
 881                                         net->cc_mod.rtcc.bw_bytes_at_last_rttc = net->cc_mod.rtcc.bw_bytes;
 882                                 }
 883                         }
 884                 }
 885                 /*
 886                  * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
 887                  * moved.
 888                  */
 889                 if (accum_moved ||
 890                     ((asoc->sctp_cmt_on_off > 0) && net->new_pseudo_cumack)) {
 891                         /* If the cumulative ack moved we can proceed */
 892                         if (net->cwnd <= net->ssthresh) {
 893                                 /* We are in slow start */
 894                                 if (net->flight_size + net->net_ack >= net->cwnd) {
 895                                         uint32_t limit;
 896
 897 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 898                                         old_cwnd = net->cwnd;
 899 #endif
 900                                         switch (asoc->sctp_cmt_on_off) {
 901                                         case SCTP_CMT_RPV1:
 902                                                 limit = (uint32_t)(((uint64_t)net->mtu *
 903                                                                     (uint64_t)SCTP_BASE_SYSCTL(sctp_L2_abc_variable) *
 904                                                                     (uint64_t)net->ssthresh) /
 905                                                                    (uint64_t)t_ssthresh);
 906                                                 incr = (uint32_t)(((uint64_t)net->net_ack *
 907                                                                    (uint64_t)net->ssthresh) /
 908                                                                   (uint64_t)t_ssthresh);
 909                                                 if (incr > limit) {
 910                                                         incr = limit;
 911                                                 }
 912                                                 if (incr == 0) {
 913                                                         incr = 1;
 914                                                 }
 915                                                 break;
 916                                         case SCTP_CMT_RPV2:
 917                                                 /* lastsa>>3;  we don't need to divide ...*/
 918                                                 srtt = net->lastsa;
 919                                                 if (srtt == 0) {
 920                                                         srtt = 1;
 921                                                 }
 922                                                 limit = (uint32_t)(((uint64_t)net->mtu *
 923                                                                     (uint64_t)SCTP_BASE_SYSCTL(sctp_L2_abc_variable) *
 924                                                                     (uint64_t)net->cwnd) /
 925                                                                    ((uint64_t)srtt * t_ucwnd_sbw));
 926                                                                    /* INCREASE FACTOR */
 927                                                 incr = (uint32_t)(((uint64_t)net->net_ack *
 928                                                                    (uint64_t)net->cwnd) /
 929                                                                   ((uint64_t)srtt * t_ucwnd_sbw));
 930                                                                   /* INCREASE FACTOR */
 931                                                 if (incr > limit) {
 932                                                         incr = limit;
 933                                                 }
 934                                                 if (incr == 0) {
 935                                                         incr = 1;
 936                                                 }
 937                                                 break;
 938                                         case SCTP_CMT_MPTCP:
 939                                                 limit = (uint32_t)(((uint64_t)net->mtu *
 940                                                                     mptcp_like_alpha *
 941                                                                     (uint64_t)SCTP_BASE_SYSCTL(sctp_L2_abc_variable)) >>
 942                                                                    SHIFT_MPTCP_MULTI);
 943                                                 incr  = (uint32_t)(((uint64_t)net->net_ack *
 944                                                                     mptcp_like_alpha) >>
 945                                                                    SHIFT_MPTCP_MULTI);
 946                                                 if (incr > limit) {
 947                                                         incr = limit;
 948                                                 }
 949                                                 if (incr > net->net_ack) {
 950                                                         incr = net->net_ack;
 951                                                 }
 952                                                 if (incr > net->mtu) {
 953                                                         incr = net->mtu;
 954                                                 }
 955                                                 break;
 956                                         default:
 957                                                 incr = net->net_ack;
 958                                                 if (incr > net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable)) {
 959                                                         incr = net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable);
 960                                                 }
 961                                                 break;
 962                                         }
 963                                         net->cwnd += incr;
 964                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 965                                                 sctp_log_cwnd(stcb, net, incr,
 966                                                               SCTP_CWND_LOG_FROM_SS);
 967                                         }
 968 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 969                                         SDT_PROBE(sctp, cwnd, net, ack,
 970                                                   stcb->asoc.my_vtag,
 971                                                   ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
 972                                                   net,
 973                                                   old_cwnd, net->cwnd);
 974 #endif
 975                                 } else {
 976                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 977                                                 sctp_log_cwnd(stcb, net, net->net_ack,
 978                                                               SCTP_CWND_LOG_NOADV_SS);
 979                                         }
 980                                 }
 981                         } else {
 982                                 /* We are in congestion avoidance */
 983                                 /*
 984                                  * Add to pba
 985                                  */
 986                                 net->partial_bytes_acked += net->net_ack;
 987
 988                                 if ((net->flight_size + net->net_ack >= net->cwnd) &&
 989                                     (net->partial_bytes_acked >= net->cwnd)) {
 990                                         net->partial_bytes_acked -= net->cwnd;
 991 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
 992                                         old_cwnd = net->cwnd;
 993 #endif
 994                                         switch (asoc->sctp_cmt_on_off) {
 995                                         case SCTP_CMT_RPV1:
 996                                                 incr = (uint32_t)(((uint64_t)net->mtu *
 997                                                                    (uint64_t)net->ssthresh) /
 998                                                                   (uint64_t)t_ssthresh);
 999                                                 if (incr == 0) {
1000                                                         incr = 1;
1001                                                 }
1002                                                 break;
1003                                         case SCTP_CMT_RPV2:
1004                                                 /* lastsa>>3;  we don't need to divide ... */
1005                                                 srtt = net->lastsa;
1006                                                 if (srtt == 0) {
1007                                                         srtt = 1;
1008                                                 }
1009                                                 incr = (uint32_t)((uint64_t)net->mtu *
1010                                                                   (uint64_t)net->cwnd /
1011                                                                   ((uint64_t)srtt *
1012                                                                    t_ucwnd_sbw));
1013                                                                   /* INCREASE FACTOR */
1014                                                 if (incr == 0) {
1015                                                         incr = 1;
1016                                                 }
1017                                                 break;
1018                                         case SCTP_CMT_MPTCP:
1019                                                 incr = (uint32_t)((mptcp_like_alpha *
1020                                                                    (uint64_t) net->cwnd) >>
1021                                                                   SHIFT_MPTCP_MULTI);
1022                                                 if (incr > net->mtu) {
1023                                                         incr = net->mtu;
1024                                                 }
1025                                                 break;
1026                                         default:
1027                                                 incr = net->mtu;
1028                                                 break;
1029                                         }
1030                                         net->cwnd += incr;
1031 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
1032                                         SDT_PROBE(sctp, cwnd, net, ack,
1033                                                   stcb->asoc.my_vtag,
1034                                                   ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
1035                                                   net,
1036                                                   old_cwnd, net->cwnd);
1037 #endif
1038                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1039                                                 sctp_log_cwnd(stcb, net, net->mtu,
1040                                                               SCTP_CWND_LOG_FROM_CA);
1041                                         }
1042                                 } else {
1043                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1044                                                 sctp_log_cwnd(stcb, net, net->net_ack,
1045                                                               SCTP_CWND_LOG_NOADV_CA);
1046                                         }
1047                                 }
1048                         }
1049                 } else {
1050                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1051                                 sctp_log_cwnd(stcb, net, net->mtu,
1052                                               SCTP_CWND_LOG_NO_CUMACK);
1053                         }
1054                 }
1055         }
1056 }
1057
1058 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
1059 static void
1060 sctp_cwnd_update_exit_pf_common(struct sctp_tcb *stcb, struct sctp_nets *net)
1061 #else
1062 static void
1063 sctp_cwnd_update_exit_pf_common(struct sctp_tcb *stcb SCTP_UNUSED, struct sctp_nets *net)
1064 #endif
1065 {
1066 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
1067         int old_cwnd;
1068
1069         old_cwnd = net->cwnd;
1070 #endif
1071         net->cwnd = net->mtu;
1072 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
1073         SDT_PROBE(sctp, cwnd, net, ack,
1074                   stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
1075                   old_cwnd, net->cwnd);
1076 #endif
1077         SCTPDBG(SCTP_DEBUG_INDATA1, "Destination %p moved from PF to reachable with cwnd %d.\n",
1078                 (void *)net, net->cwnd);
1079 }
1080
1081
1082 static void
1083 sctp_cwnd_update_after_timeout(struct sctp_tcb *stcb, struct sctp_nets *net)
1084 {
1085         int old_cwnd = net->cwnd;
1086         uint32_t t_ssthresh, t_cwnd;
1087         uint64_t t_ucwnd_sbw;
1088
1089         /* MT FIXME: Don't compute this over and over again */
1090         t_ssthresh = 0;
1091         t_cwnd = 0;
1092         if ((stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) ||
1093             (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV2)) {
1094                 struct sctp_nets *lnet;
1095                 uint32_t srtt;
1096
1097                 t_ucwnd_sbw = 0;
1098                 TAILQ_FOREACH(lnet, &stcb->asoc.nets, sctp_next) {
1099                         t_ssthresh += lnet->ssthresh;
1100                         t_cwnd += lnet->cwnd;
1101                         srtt = lnet->lastsa;
1102                         /* lastsa>>3;  we don't need to divide ... */
1103                         if (srtt > 0) {
1104                                 t_ucwnd_sbw += (uint64_t)lnet->cwnd / (uint64_t)srtt;
1105                         }
1106                 }
1107                 if (t_ssthresh < 1) {
1108                         t_ssthresh = 1;
1109                 }
1110                 if (t_ucwnd_sbw < 1) {
1111                         t_ucwnd_sbw = 1;
1112                 }
1113                 if (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) {
1114                         net->ssthresh = (uint32_t)(((uint64_t)4 *
1115                                                     (uint64_t)net->mtu *
1116                                                     (uint64_t)net->ssthresh) /
1117                                                    (uint64_t)t_ssthresh);
1118                 } else {
1119                         uint64_t cc_delta;
1120
1121                         srtt = net->lastsa;
1122                         /* lastsa>>3;  we don't need to divide ... */
1123                         if (srtt == 0) {
1124                                 srtt = 1;
1125                         }
1126                         cc_delta = t_ucwnd_sbw * (uint64_t)srtt / 2;
1127                         if (cc_delta < t_cwnd) {
1128                                 net->ssthresh = (uint32_t)((uint64_t)t_cwnd - cc_delta);
1129                         } else {
1130                                 net->ssthresh  = net->mtu;
1131                         }
1132                 }
1133                 if ((net->cwnd > t_cwnd / 2) &&
1134                     (net->ssthresh < net->cwnd - t_cwnd / 2)) {
1135                         net->ssthresh = net->cwnd - t_cwnd / 2;
1136                 }
1137                 if (net->ssthresh < net->mtu) {
1138                         net->ssthresh = net->mtu;
1139                 }
1140         } else {
1141                 net->ssthresh = max(net->cwnd / 2, 4 * net->mtu);
1142         }
1143         net->cwnd = net->mtu;
1144         net->partial_bytes_acked = 0;
1145 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
1146         SDT_PROBE(sctp, cwnd, net, to,
1147                   stcb->asoc.my_vtag,
1148                   ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
1149                   net,
1150                   old_cwnd, net->cwnd);
1151 #endif
1152         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1153                 sctp_log_cwnd(stcb, net, net->cwnd - old_cwnd, SCTP_CWND_LOG_FROM_RTX);
1154         }
1155 }
1156
1157 static void
1158 sctp_cwnd_update_after_ecn_echo_common(struct sctp_tcb *stcb, struct sctp_nets *net,
1159                                             int in_window, int num_pkt_lost, int use_rtcc)
1160 {
1161         int old_cwnd = net->cwnd;
1162         if ((use_rtcc) && (net->lan_type == SCTP_LAN_LOCAL) && (net->cc_mod.rtcc.use_dccc_ecn)) {
1163                 /* Data center Congestion Control */
1164                 if (in_window == 0) {
1165                         /* Go to CA with the cwnd at the point we sent
1166                          * the TSN that was marked with a CE.
1167                          */
1168                         if (net->ecn_prev_cwnd < net->cwnd) {
1169                                 /* Restore to prev cwnd */
1170                                 net->cwnd = net->ecn_prev_cwnd - (net->mtu * num_pkt_lost);
1171                         } else {
1172                                 /* Just cut in 1/2 */
1173                                 net->cwnd /= 2;
1174                         }
1175                         /* Drop to CA */
1176                         net->ssthresh = net->cwnd - (num_pkt_lost * net->mtu);
1177                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1178                                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
1179                         }
1180                 } else {
1181                         /* Further tuning down required over the drastic orginal cut */
1182                         net->ssthresh -= (net->mtu * num_pkt_lost);
1183                         net->cwnd -= (net->mtu * num_pkt_lost);
1184                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1185                                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
1186                         }
1187
1188                 }
1189                 SCTP_STAT_INCR(sctps_ecnereducedcwnd);
1190         }  else {
1191                 if (in_window == 0) {
1192                         SCTP_STAT_INCR(sctps_ecnereducedcwnd);
1193                         net->ssthresh = net->cwnd / 2;
1194                         if (net->ssthresh < net->mtu) {
1195                                 net->ssthresh = net->mtu;
1196                                 /* here back off the timer as well, to slow us down */
1197                                 net->RTO <<= 1;
1198                         }
1199                         net->cwnd = net->ssthresh;
1200 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
1201                         SDT_PROBE(sctp, cwnd, net, ecn,
1202                                   stcb->asoc.my_vtag,
1203                                   ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
1204                                   net,
1205                                   old_cwnd, net->cwnd);
1206 #endif
1207                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1208                                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
1209                         }
1210                 }
1211         }
1212
1213 }
1214
1215 static void
1216 sctp_cwnd_update_after_packet_dropped(struct sctp_tcb *stcb,
1217         struct sctp_nets *net, struct sctp_pktdrop_chunk *cp,
1218         uint32_t *bottle_bw, uint32_t *on_queue)
1219 {
1220         uint32_t bw_avail;
1221         unsigned int incr;
1222         int old_cwnd = net->cwnd;
1223
1224         /* get bottle neck bw */
1225         *bottle_bw = ntohl(cp->bottle_bw);
1226         /* and whats on queue */
1227         *on_queue = ntohl(cp->current_onq);
1228         /*
1229          * adjust the on-queue if our flight is more it could be
1230          * that the router has not yet gotten data "in-flight" to it
1231          */
1232         if (*on_queue < net->flight_size) {
1233                 *on_queue = net->flight_size;
1234         }
1235         /* rtt is measured in micro seconds, bottle_bw in bytes per second */
1236         bw_avail = (uint32_t)(((uint64_t)(*bottle_bw) * net->rtt) / (uint64_t)1000000);
1237         if (bw_avail > *bottle_bw) {
1238                 /*
1239                  * Cap the growth to no more than the bottle neck.
1240                  * This can happen as RTT slides up due to queues.
1241                  * It also means if you have more than a 1 second
1242                  * RTT with a empty queue you will be limited to the
1243                  * bottle_bw per second no matter if other points
1244                  * have 1/2 the RTT and you could get more out...
1245                  */
1246                 bw_avail = *bottle_bw;
1247         }
1248         if (*on_queue > bw_avail) {
1249                 /*
1250                  * No room for anything else don't allow anything
1251                  * else to be "added to the fire".
1252                  */
1253                 int seg_inflight, seg_onqueue, my_portion;
1254
1255                 net->partial_bytes_acked = 0;
1256                 /* how much are we over queue size? */
1257                 incr = *on_queue - bw_avail;
1258                 if (stcb->asoc.seen_a_sack_this_pkt) {
1259                         /*
1260                          * undo any cwnd adjustment that the sack
1261                          * might have made
1262                          */
1263                         net->cwnd = net->prev_cwnd;
1264                 }
1265                 /* Now how much of that is mine? */
1266                 seg_inflight = net->flight_size / net->mtu;
1267                 seg_onqueue = *on_queue / net->mtu;
1268                 my_portion = (incr * seg_inflight) / seg_onqueue;
1269
1270                 /* Have I made an adjustment already */
1271                 if (net->cwnd > net->flight_size) {
1272                         /*
1273                          * for this flight I made an adjustment we
1274                          * need to decrease the portion by a share
1275                          * our previous adjustment.
1276                          */
1277                         int diff_adj;
1278
1279                         diff_adj = net->cwnd - net->flight_size;
1280                         if (diff_adj > my_portion)
1281                                 my_portion = 0;
1282                         else
1283                                 my_portion -= diff_adj;
1284                 }
1285                 /*
1286                  * back down to the previous cwnd (assume we have
1287                  * had a sack before this packet). minus what ever
1288                  * portion of the overage is my fault.
1289                  */
1290                 net->cwnd -= my_portion;
1291
1292                 /* we will NOT back down more than 1 MTU */
1293                 if (net->cwnd <= net->mtu) {
1294                         net->cwnd = net->mtu;
1295                 }
1296                 /* force into CA */
1297                 net->ssthresh = net->cwnd - 1;
1298         } else {
1299                 /*
1300                  * Take 1/4 of the space left or max burst up ..
1301                  * whichever is less.
1302                  */
1303                 incr = (bw_avail - *on_queue) >> 2;
1304                 if ((stcb->asoc.max_burst > 0) &&
1305                     (stcb->asoc.max_burst * net->mtu < incr)) {
1306                         incr = stcb->asoc.max_burst * net->mtu;
1307                 }
1308                 net->cwnd += incr;
1309         }
1310         if (net->cwnd > bw_avail) {
1311                 /* We can't exceed the pipe size */
1312                 net->cwnd = bw_avail;
1313         }
1314         if (net->cwnd < net->mtu) {
1315                 /* We always have 1 MTU */
1316                 net->cwnd = net->mtu;
1317         }
1318
1319         if (net->cwnd - old_cwnd != 0) {
1320                 /* log only changes */
1321 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
1322                 SDT_PROBE(sctp, cwnd, net, pd,
1323                           stcb->asoc.my_vtag,
1324                           ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
1325                           net,
1326                           old_cwnd, net->cwnd);
1327 #endif
1328                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1329                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
1330                                 SCTP_CWND_LOG_FROM_SAT);
1331                 }
1332         }
1333 }
1334
1335 static void
1336 sctp_cwnd_update_after_output(struct sctp_tcb *stcb,
1337                               struct sctp_nets *net, int burst_limit)
1338 {
1339         int old_cwnd = net->cwnd;
1340
1341         if (net->ssthresh < net->cwnd)
1342                 net->ssthresh = net->cwnd;
1343         if (burst_limit) {
1344                 net->cwnd = (net->flight_size + (burst_limit * net->mtu));
1345 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
1346                 SDT_PROBE(sctp, cwnd, net, bl,
1347                           stcb->asoc.my_vtag,
1348                           ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
1349                           net,
1350                           old_cwnd, net->cwnd);
1351 #endif
1352                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1353                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_BRST);
1354                 }
1355         }
1356 }
1357
1358 static void
1359 sctp_cwnd_update_after_sack(struct sctp_tcb *stcb,
1360                             struct sctp_association *asoc,
1361                             int accum_moved, int reneged_all, int will_exit)
1362 {
1363         /* Passing a zero argument in last disables the rtcc algoritm */
1364         sctp_cwnd_update_after_sack_common(stcb, asoc, accum_moved, reneged_all, will_exit, 0);
1365 }
1366
1367 static void
1368 sctp_cwnd_update_after_ecn_echo(struct sctp_tcb *stcb, struct sctp_nets *net,
1369         int in_window, int num_pkt_lost)
1370 {
1371         /* Passing a zero argument in last disables the rtcc algoritm */
1372         sctp_cwnd_update_after_ecn_echo_common(stcb, net, in_window, num_pkt_lost, 0);
1373 }
1374
1375 /* Here starts the RTCCVAR type CC invented by RRS which
1376  * is a slight mod to RFC2581. We reuse a common routine or
1377  * two since these algoritms are so close and need to
1378  * remain the same.
1379  */
1380 static void
1381 sctp_cwnd_update_rtcc_after_ecn_echo(struct sctp_tcb *stcb, struct sctp_nets *net,
1382                                      int in_window, int num_pkt_lost)
1383 {
1384         sctp_cwnd_update_after_ecn_echo_common(stcb, net, in_window, num_pkt_lost, 1);
1385 }
1386
1387
1388 static
1389 void sctp_cwnd_update_rtcc_tsn_acknowledged(struct sctp_nets *net,
1390                                             struct sctp_tmit_chunk *tp1)
1391 {
1392         net->cc_mod.rtcc.bw_bytes += tp1->send_size;
1393 }
1394
1395 static void
1396 sctp_cwnd_prepare_rtcc_net_for_sack(struct sctp_tcb *stcb SCTP_UNUSED,
1397                                     struct sctp_nets *net)
1398 {
1399         if (net->cc_mod.rtcc.tls_needs_set > 0) {
1400                 /* We had a bw measurment going on */
1401                 struct timeval ltls;
1402                 SCTP_GETPTIME_TIMEVAL(&ltls);
1403                 timevalsub(&ltls, &net->cc_mod.rtcc.tls);
1404                 net->cc_mod.rtcc.new_tot_time = (ltls.tv_sec * 1000000) + ltls.tv_usec;
1405         }
1406 }
1407
1408 static void
1409 sctp_cwnd_new_rtcc_transmission_begins(struct sctp_tcb *stcb,
1410                                        struct sctp_nets *net)
1411 {
1412 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
1413         uint64_t vtag, probepoint;
1414
1415 #endif
1416         if (net->cc_mod.rtcc.lbw) {
1417 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
1418                 /* Clear the old bw.. we went to 0 in-flight */
1419                 vtag = (net->rtt << 32) | (((uint32_t)(stcb->sctp_ep->sctp_lport)) << 16) |
1420                         (stcb->rport);
1421                 probepoint = (((uint64_t)net->cwnd) << 32);
1422                 /* Probe point 8 */
1423                 probepoint |=  ((8 << 16) | 0);
1424                 SDT_PROBE(sctp, cwnd, net, rttvar,
1425                           vtag,
1426                           ((net->cc_mod.rtcc.lbw << 32) | 0),
1427                           ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
1428                           net->flight_size,
1429                           probepoint);
1430 #endif
1431                 net->cc_mod.rtcc.lbw_rtt = 0;
1432                 net->cc_mod.rtcc.cwnd_at_bw_set = 0;
1433                 net->cc_mod.rtcc.lbw = 0;
1434                 net->cc_mod.rtcc.bw_bytes_at_last_rttc = 0;
1435                 net->cc_mod.rtcc.vol_reduce = 0;
1436                 net->cc_mod.rtcc.bw_tot_time = 0;
1437                 net->cc_mod.rtcc.bw_bytes = 0;
1438                 net->cc_mod.rtcc.tls_needs_set = 0;
1439                 if (net->cc_mod.rtcc.steady_step) {
1440                         net->cc_mod.rtcc.vol_reduce = 0;
1441                         net->cc_mod.rtcc.step_cnt = 0;
1442                         net->cc_mod.rtcc.last_step_state = 0;
1443                 }
1444                 if (net->cc_mod.rtcc.ret_from_eq) {
1445                         /* less aggressive one - reset cwnd too */
1446                         uint32_t cwnd_in_mtu, cwnd;
1447
1448                         cwnd_in_mtu = SCTP_BASE_SYSCTL(sctp_initial_cwnd);
1449                         if (cwnd_in_mtu == 0) {
1450                                 /* Using 0 means that the value of RFC 4960 is used. */
1451                                 cwnd = min((net->mtu * 4), max((2 * net->mtu), SCTP_INITIAL_CWND));
1452                         } else {
1453                                 /*
1454                                  * We take the minimum of the burst limit and the
1455                                  * initial congestion window.
1456                                  */
1457                                 if ((stcb->asoc.max_burst > 0) && (cwnd_in_mtu > stcb->asoc.max_burst))
1458                                         cwnd_in_mtu = stcb->asoc.max_burst;
1459                                 cwnd = (net->mtu - sizeof(struct sctphdr)) * cwnd_in_mtu;
1460                         }
1461                         if (net->cwnd > cwnd) {
1462                                 /* Only set if we are not a timeout (i.e. down to 1 mtu) */
1463                                 net->cwnd = cwnd;
1464                         }
1465                 }
1466         }
1467 }
1468
1469 static void
1470 sctp_set_rtcc_initial_cc_param(struct sctp_tcb *stcb,
1471                                struct sctp_nets *net)
1472 {
1473 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
1474         uint64_t vtag, probepoint;
1475
1476 #endif
1477         sctp_set_initial_cc_param(stcb, net);
1478         stcb->asoc.use_precise_time = 1;
1479 #if defined(__FreeBSD__) && __FreeBSD_version >= 803000
1480         probepoint = (((uint64_t)net->cwnd) << 32);
1481         probepoint |=  ((9 << 16) | 0);
1482         vtag = (net->rtt << 32) |
1483                 (((uint32_t)(stcb->sctp_ep->sctp_lport)) << 16) |
1484                 (stcb->rport);
1485         SDT_PROBE(sctp, cwnd, net, rttvar,
1486                   vtag,
1487                   0,
1488                   0,
1489                   0,
1490                   probepoint);
1491 #endif
1492         net->cc_mod.rtcc.lbw_rtt = 0;
1493         net->cc_mod.rtcc.cwnd_at_bw_set = 0;
1494         net->cc_mod.rtcc.vol_reduce = 0;
1495         net->cc_mod.rtcc.lbw = 0;
1496         net->cc_mod.rtcc.vol_reduce = 0;
1497         net->cc_mod.rtcc.bw_bytes_at_last_rttc = 0;
1498         net->cc_mod.rtcc.bw_tot_time = 0;
1499         net->cc_mod.rtcc.bw_bytes = 0;
1500         net->cc_mod.rtcc.tls_needs_set = 0;
1501         net->cc_mod.rtcc.ret_from_eq = SCTP_BASE_SYSCTL(sctp_rttvar_eqret);
1502         net->cc_mod.rtcc.steady_step = SCTP_BASE_SYSCTL(sctp_steady_step);
1503         net->cc_mod.rtcc.use_dccc_ecn = SCTP_BASE_SYSCTL(sctp_use_dccc_ecn);
1504         net->cc_mod.rtcc.step_cnt = 0;
1505         net->cc_mod.rtcc.last_step_state = 0;
1506
1507
1508 }
1509
1510 static int
1511 sctp_cwnd_rtcc_socket_option(struct sctp_tcb *stcb, int setorget,
1512                              struct sctp_cc_option *cc_opt)
1513 {
1514         struct sctp_nets *net;
1515         if (setorget == 1) {
1516                 /* a set */
1517                 if (cc_opt->option == SCTP_CC_OPT_RTCC_SETMODE) {
1518                         if ((cc_opt->aid_value.assoc_value != 0) &&
1519                             (cc_opt->aid_value.assoc_value != 1)) {
1520                                 return (EINVAL);
1521                         }
1522                         TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
1523                                 net->cc_mod.rtcc.ret_from_eq = cc_opt->aid_value.assoc_value;
1524                         }
1525                 } else if (cc_opt->option == SCTP_CC_OPT_USE_DCCC_ECN) {
1526                         if ((cc_opt->aid_value.assoc_value != 0) &&
1527                             (cc_opt->aid_value.assoc_value != 1)) {
1528                                 return (EINVAL);
1529                         }
1530                         TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
1531                                 net->cc_mod.rtcc.use_dccc_ecn = cc_opt->aid_value.assoc_value;
1532                         }
1533                 } else if (cc_opt->option == SCTP_CC_OPT_STEADY_STEP) {
1534                         TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
1535                                 net->cc_mod.rtcc.steady_step = cc_opt->aid_value.assoc_value;
1536                         }
1537                 } else {
1538                         return (EINVAL);
1539                 }
1540         } else {
1541                 /* a get */
1542                 if (cc_opt->option == SCTP_CC_OPT_RTCC_SETMODE) {
1543                         net = TAILQ_FIRST(&stcb->asoc.nets);
1544                         if (net == NULL) {
1545                                 return (EFAULT);
1546                         }
1547                         cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.ret_from_eq;
1548                 } else if (cc_opt->option == SCTP_CC_OPT_USE_DCCC_ECN) {
1549                         net = TAILQ_FIRST(&stcb->asoc.nets);
1550                         if (net == NULL) {
1551                                 return (EFAULT);
1552                         }
1553                         cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.use_dccc_ecn;
1554                 } else if (cc_opt->option == SCTP_CC_OPT_STEADY_STEP) {
1555                         net = TAILQ_FIRST(&stcb->asoc.nets);
1556                         if (net == NULL) {
1557                                 return (EFAULT);
1558                         }
1559                         cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.steady_step;
1560                 } else {
1561                         return (EINVAL);
1562                 }
1563         }
1564         return (0);
1565 }
1566
1567 static void
1568 sctp_cwnd_update_rtcc_packet_transmitted(struct sctp_tcb *stcb SCTP_UNUSED,
1569                                          struct sctp_nets *net)
1570 {
1571         if (net->cc_mod.rtcc.tls_needs_set == 0) {
1572                 SCTP_GETPTIME_TIMEVAL(&net->cc_mod.rtcc.tls);
1573                 net->cc_mod.rtcc.tls_needs_set = 2;
1574         }
1575 }
1576
1577 static void
1578 sctp_cwnd_update_rtcc_after_sack(struct sctp_tcb *stcb,
1579                                  struct sctp_association *asoc,
1580                                  int accum_moved, int reneged_all, int will_exit)
1581 {
1582         /* Passing a one argument at the last enables the rtcc algoritm */
1583         sctp_cwnd_update_after_sack_common(stcb, asoc, accum_moved, reneged_all, will_exit, 1);
1584 }
1585
1586 static void
1587 sctp_rtt_rtcc_calculated(struct sctp_tcb *stcb SCTP_UNUSED,
1588                          struct sctp_nets *net,
1589                          struct timeval *now SCTP_UNUSED)
1590 {
1591         net->cc_mod.rtcc.rtt_set_this_sack = 1;
1592 }
1593
1594 /* Here starts Sally Floyds HS-TCP */
1595
1596 struct sctp_hs_raise_drop {
1597         int32_t cwnd;
1598         int32_t increase;
1599         int32_t drop_percent;
1600 };
1601
1602 #define SCTP_HS_TABLE_SIZE 73
1603
1604 struct sctp_hs_raise_drop sctp_cwnd_adjust[SCTP_HS_TABLE_SIZE] = {
1605         {38, 1, 50},            /* 0   */
1606         {118, 2, 44},           /* 1   */
1607         {221, 3, 41},           /* 2   */
1608         {347, 4, 38},           /* 3   */
1609         {495, 5, 37},           /* 4   */
1610         {663, 6, 35},           /* 5   */
1611         {851, 7, 34},           /* 6   */
1612         {1058, 8, 33},          /* 7   */
1613         {1284, 9, 32},          /* 8   */
1614         {1529, 10, 31},         /* 9   */
1615         {1793, 11, 30},         /* 10  */
1616         {2076, 12, 29},         /* 11  */
1617         {2378, 13, 28},         /* 12  */
1618         {2699, 14, 28},         /* 13  */
1619         {3039, 15, 27},         /* 14  */
1620         {3399, 16, 27},         /* 15  */
1621         {3778, 17, 26},         /* 16  */
1622         {4177, 18, 26},         /* 17  */
1623         {4596, 19, 25},         /* 18  */
1624         {5036, 20, 25},         /* 19  */
1625         {5497, 21, 24},         /* 20  */
1626         {5979, 22, 24},         /* 21  */
1627         {6483, 23, 23},         /* 22  */
1628         {7009, 24, 23},         /* 23  */
1629         {7558, 25, 22},         /* 24  */
1630         {8130, 26, 22},         /* 25  */
1631         {8726, 27, 22},         /* 26  */
1632         {9346, 28, 21},         /* 27  */
1633         {9991, 29, 21},         /* 28  */
1634         {10661, 30, 21},        /* 29  */
1635         {11358, 31, 20},        /* 30  */
1636         {12082, 32, 20},        /* 31  */
1637         {12834, 33, 20},        /* 32  */
1638         {13614, 34, 19},        /* 33  */
1639         {14424, 35, 19},        /* 34  */
1640         {15265, 36, 19},        /* 35  */
1641         {16137, 37, 19},        /* 36  */
1642         {17042, 38, 18},        /* 37  */
1643         {17981, 39, 18},        /* 38  */
1644         {18955, 40, 18},        /* 39  */
1645         {19965, 41, 17},        /* 40  */
1646         {21013, 42, 17},        /* 41  */
1647         {22101, 43, 17},        /* 42  */
1648         {23230, 44, 17},        /* 43  */
1649         {24402, 45, 16},        /* 44  */
1650         {25618, 46, 16},        /* 45  */
1651         {26881, 47, 16},        /* 46  */
1652         {28193, 48, 16},        /* 47  */
1653         {29557, 49, 15},        /* 48  */
1654         {30975, 50, 15},        /* 49  */
1655         {32450, 51, 15},        /* 50  */
1656         {33986, 52, 15},        /* 51  */
1657         {35586, 53, 14},        /* 52  */
1658         {37253, 54, 14},        /* 53  */
1659         {38992, 55, 14},        /* 54  */
1660         {40808, 56, 14},        /* 55  */
1661         {42707, 57, 13},        /* 56  */
1662         {44694, 58, 13},        /* 57  */
1663         {46776, 59, 13},        /* 58  */
1664         {48961, 60, 13},        /* 59  */
1665         {51258, 61, 13},        /* 60  */
1666         {53677, 62, 12},        /* 61  */
1667         {56230, 63, 12},        /* 62  */
1668         {58932, 64, 12},        /* 63  */
1669         {61799, 65, 12},        /* 64  */
1670         {64851, 66, 11},        /* 65  */
1671         {68113, 67, 11},        /* 66  */
1672         {71617, 68, 11},        /* 67  */
1673         {75401, 69, 10},        /* 68  */
1674         {79517, 70, 10},        /* 69  */
1675         {84035, 71, 10},        /* 70  */
1676         {89053, 72, 10},        /* 71  */
1677         {94717, 73, 9}          /* 72  */
1678 };
1679
1680 static void
1681 sctp_hs_cwnd_increase(struct sctp_tcb *stcb, struct sctp_nets *net)
1682 {
1683         int cur_val, i, indx, incr;
1684
1685         cur_val = net->cwnd >> 10;
1686         indx = SCTP_HS_TABLE_SIZE - 1;
1687
1688         if (cur_val < sctp_cwnd_adjust[0].cwnd) {
1689                 /* normal mode */
1690                 if (net->net_ack > net->mtu) {
1691                         net->cwnd += net->mtu;
1692                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1693                                 sctp_log_cwnd(stcb, net, net->mtu, SCTP_CWND_LOG_FROM_SS);
1694                         }
1695                 } else {
1696                         net->cwnd += net->net_ack;
1697                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1698                                 sctp_log_cwnd(stcb, net, net->net_ack, SCTP_CWND_LOG_FROM_SS);
1699                         }
1700                 }
1701         } else {
1702                 for (i = net->last_hs_used; i < SCTP_HS_TABLE_SIZE; i++) {
1703                         if (cur_val < sctp_cwnd_adjust[i].cwnd) {
1704                                 indx = i;
1705                                 break;
1706                         }
1707                 }
1708                 net->last_hs_used = indx;
1709                 incr = ((sctp_cwnd_adjust[indx].increase) << 10);
1710                 net->cwnd += incr;
1711                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1712                         sctp_log_cwnd(stcb, net, incr, SCTP_CWND_LOG_FROM_SS);
1713                 }
1714         }
1715 }
1716
1717 static void
1718 sctp_hs_cwnd_decrease(struct sctp_tcb *stcb, struct sctp_nets *net)
1719 {
1720         int cur_val, i, indx;
1721         int old_cwnd = net->cwnd;
1722
1723         cur_val = net->cwnd >> 10;
1724         if (cur_val < sctp_cwnd_adjust[0].cwnd) {
1725                 /* normal mode */
1726                 net->ssthresh = net->cwnd / 2;
1727                 if (net->ssthresh < (net->mtu * 2)) {
1728                         net->ssthresh = 2 * net->mtu;
1729                 }
1730                 net->cwnd = net->ssthresh;
1731         } else {
1732                 /* drop by the proper amount */
1733                 net->ssthresh = net->cwnd - (int)((net->cwnd / 100) *
1734                     sctp_cwnd_adjust[net->last_hs_used].drop_percent);
1735                 net->cwnd = net->ssthresh;
1736                 /* now where are we */
1737                 indx = net->last_hs_used;
1738                 cur_val = net->cwnd >> 10;
1739                 /* reset where we are in the table */
1740                 if (cur_val < sctp_cwnd_adjust[0].cwnd) {
1741                         /* feel out of hs */
1742                         net->last_hs_used = 0;
1743                 } else {
1744                         for (i = indx; i >= 1; i--) {
1745                                 if (cur_val > sctp_cwnd_adjust[i - 1].cwnd) {
1746                                         break;
1747                                 }
1748                         }
1749                         net->last_hs_used = indx;
1750                 }
1751         }
1752         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1753                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_FR);
1754         }
1755 }
1756
1757 static void
1758 sctp_hs_cwnd_update_after_fr(struct sctp_tcb *stcb,
1759                              struct sctp_association *asoc)
1760 {
1761         struct sctp_nets *net;
1762                 /*
1763          * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off > 0) &&
1764          * (net->fast_retran_loss_recovery == 0)))
1765          */
1766         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
1767                 if ((asoc->fast_retran_loss_recovery == 0) ||
1768                     (asoc->sctp_cmt_on_off > 0)) {
1769                         /* out of a RFC2582 Fast recovery window? */
1770                         if (net->net_ack > 0) {
1771                                 /*
1772                                  * per section 7.2.3, are there any
1773                                  * destinations that had a fast retransmit
1774                                  * to them. If so what we need to do is
1775                                  * adjust ssthresh and cwnd.
1776                                  */
1777                                 struct sctp_tmit_chunk *lchk;
1778
1779                                 sctp_hs_cwnd_decrease(stcb, net);
1780
1781                                 lchk = TAILQ_FIRST(&asoc->send_queue);
1782
1783                                 net->partial_bytes_acked = 0;
1784                                 /* Turn on fast recovery window */
1785                                 asoc->fast_retran_loss_recovery = 1;
1786                                 if (lchk == NULL) {
1787                                         /* Mark end of the window */
1788                                         asoc->fast_recovery_tsn = asoc->sending_seq - 1;
1789                                 } else {
1790                                         asoc->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
1791                                 }
1792
1793                                 /*
1794                                  * CMT fast recovery -- per destination
1795                                  * recovery variable.
1796                                  */
1797                                 net->fast_retran_loss_recovery = 1;
1798
1799                                 if (lchk == NULL) {
1800                                         /* Mark end of the window */
1801                                         net->fast_recovery_tsn = asoc->sending_seq - 1;
1802                                 } else {
1803                                         net->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
1804                                 }
1805
1806                                 sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
1807                                                 stcb->sctp_ep, stcb, net, SCTP_FROM_SCTP_INDATA+SCTP_LOC_32);
1808                                 sctp_timer_start(SCTP_TIMER_TYPE_SEND,
1809                                                  stcb->sctp_ep, stcb, net);
1810                         }
1811                 } else if (net->net_ack > 0) {
1812                         /*
1813                          * Mark a peg that we WOULD have done a cwnd
1814                          * reduction but RFC2582 prevented this action.
1815                          */
1816                         SCTP_STAT_INCR(sctps_fastretransinrtt);
1817                 }
1818         }
1819 }
1820
1821 static void
1822 sctp_hs_cwnd_update_after_sack(struct sctp_tcb *stcb,
1823                  struct sctp_association *asoc,
1824                  int accum_moved, int reneged_all SCTP_UNUSED, int will_exit)
1825 {
1826         struct sctp_nets *net;
1827         /******************************/
1828         /* update cwnd and Early FR   */
1829         /******************************/
1830         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
1831
1832 #ifdef JANA_CMT_FAST_RECOVERY
1833                 /*
1834                  * CMT fast recovery code. Need to debug.
1835                  */
1836                 if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
1837                         if (SCTP_TSN_GE(asoc->last_acked_seq, net->fast_recovery_tsn) ||
1838                             SCTP_TSN_GE(net->pseudo_cumack,net->fast_recovery_tsn)) {
1839                                 net->will_exit_fast_recovery = 1;
1840                         }
1841                 }
1842 #endif
1843                 /* if nothing was acked on this destination skip it */
1844                 if (net->net_ack == 0) {
1845                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1846                                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
1847                         }
1848                         continue;
1849                 }
1850 #ifdef JANA_CMT_FAST_RECOVERY
1851                 /* CMT fast recovery code
1852                  */
1853                 /*
1854                 if (sctp_cmt_on_off > 0 && net->fast_retran_loss_recovery && net->will_exit_fast_recovery == 0) {
1855                     @@@ Do something
1856                  }
1857                  else if (sctp_cmt_on_off == 0 && asoc->fast_retran_loss_recovery && will_exit == 0) {
1858                 */
1859 #endif
1860
1861                  if (asoc->fast_retran_loss_recovery &&
1862                      (will_exit == 0) &&
1863                      (asoc->sctp_cmt_on_off == 0)) {
1864                         /*
1865                          * If we are in loss recovery we skip any cwnd
1866                          * update
1867                          */
1868                         return;
1869                 }
1870                 /*
1871                  * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
1872                  * moved.
1873                  */
1874                 if (accum_moved ||
1875                     ((asoc->sctp_cmt_on_off > 0) && net->new_pseudo_cumack)) {
1876                         /* If the cumulative ack moved we can proceed */
1877                         if (net->cwnd <= net->ssthresh) {
1878                                 /* We are in slow start */
1879                                 if (net->flight_size + net->net_ack >= net->cwnd) {
1880
1881                                         sctp_hs_cwnd_increase(stcb, net);
1882
1883                                 } else {
1884                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1885                                                 sctp_log_cwnd(stcb, net, net->net_ack,
1886                                                         SCTP_CWND_LOG_NOADV_SS);
1887                                         }
1888                                 }
1889                         } else {
1890                                 /* We are in congestion avoidance */
1891                                 net->partial_bytes_acked += net->net_ack;
1892                                 if ((net->flight_size + net->net_ack >= net->cwnd) &&
1893                                     (net->partial_bytes_acked >= net->cwnd)) {
1894                                         net->partial_bytes_acked -= net->cwnd;
1895                                         net->cwnd += net->mtu;
1896                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1897                                                 sctp_log_cwnd(stcb, net, net->mtu,
1898                                                         SCTP_CWND_LOG_FROM_CA);
1899                                         }
1900                                 } else {
1901                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1902                                                 sctp_log_cwnd(stcb, net, net->net_ack,
1903                                                         SCTP_CWND_LOG_NOADV_CA);
1904                                         }
1905                                 }
1906                         }
1907                 } else {
1908                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1909                                 sctp_log_cwnd(stcb, net, net->mtu,
1910                                         SCTP_CWND_LOG_NO_CUMACK);
1911                         }
1912                 }
1913         }
1914 }
1915
1916
1917 /*
1918  * H-TCP congestion control. The algorithm is detailed in:
1919  * R.N.Shorten, D.J.Leith:
1920  *   "H-TCP: TCP for high-speed and long-distance networks"
1921  *   Proc. PFLDnet, Argonne, 2004.
1922  * http://www.hamilton.ie/net/htcp3.pdf
1923  */
1924
1925
1926 static int use_rtt_scaling = 1;
1927 static int use_bandwidth_switch = 1;
1928
1929 static inline int
1930 between(uint32_t seq1, uint32_t seq2, uint32_t seq3)
1931 {
1932         return (seq3 - seq2 >= seq1 - seq2);
1933 }
1934
1935 static inline uint32_t
1936 htcp_cong_time(struct htcp *ca)
1937 {
1938         return (sctp_get_tick_count() - ca->last_cong);
1939 }
1940
1941 static inline uint32_t
1942 htcp_ccount(struct htcp *ca)
1943 {
1944         return (htcp_cong_time(ca)/ca->minRTT);
1945 }
1946
1947 static inline void
1948 htcp_reset(struct htcp *ca)
1949 {
1950         ca->undo_last_cong = ca->last_cong;
1951         ca->undo_maxRTT = ca->maxRTT;
1952         ca->undo_old_maxB = ca->old_maxB;
1953         ca->last_cong = sctp_get_tick_count();
1954 }
1955
1956 #ifdef SCTP_NOT_USED
1957
1958 static uint32_t
1959 htcp_cwnd_undo(struct sctp_tcb *stcb, struct sctp_nets *net)
1960 {
1961         net->cc_mod.htcp_ca.last_cong = net->cc_mod.htcp_ca.undo_last_cong;
1962         net->cc_mod.htcp_ca.maxRTT = net->cc_mod.htcp_ca.undo_maxRTT;
1963         net->cc_mod.htcp_ca.old_maxB = net->cc_mod.htcp_ca.undo_old_maxB;
1964         return (max(net->cwnd, ((net->ssthresh/net->mtu<<7)/net->cc_mod.htcp_ca.beta)*net->mtu));
1965 }
1966
1967 #endif
1968
1969 static inline void
1970 measure_rtt(struct sctp_nets *net)
1971 {
1972         uint32_t srtt = net->lastsa>>SCTP_RTT_SHIFT;
1973
1974         /* keep track of minimum RTT seen so far, minRTT is zero at first */
1975         if (net->cc_mod.htcp_ca.minRTT > srtt || !net->cc_mod.htcp_ca.minRTT)
1976                 net->cc_mod.htcp_ca.minRTT = srtt;
1977
1978         /* max RTT */
1979         if (net->fast_retran_ip == 0 && net->ssthresh < 0xFFFF && htcp_ccount(&net->cc_mod.htcp_ca) > 3) {
1980                 if (net->cc_mod.htcp_ca.maxRTT < net->cc_mod.htcp_ca.minRTT)
1981                         net->cc_mod.htcp_ca.maxRTT = net->cc_mod.htcp_ca.minRTT;
1982                 if (net->cc_mod.htcp_ca.maxRTT < srtt && srtt <= net->cc_mod.htcp_ca.maxRTT+MSEC_TO_TICKS(20))
1983                         net->cc_mod.htcp_ca.maxRTT = srtt;
1984         }
1985 }
1986
1987 static void
1988 measure_achieved_throughput(struct sctp_nets *net)
1989 {
1990         uint32_t now = sctp_get_tick_count();
1991
1992         if (net->fast_retran_ip == 0)
1993                 net->cc_mod.htcp_ca.bytes_acked = net->net_ack;
1994
1995         if (!use_bandwidth_switch)
1996                 return;
1997
1998         /* achieved throughput calculations */
1999         /* JRS - not 100% sure of this statement */
2000         if (net->fast_retran_ip == 1) {
2001                 net->cc_mod.htcp_ca.bytecount = 0;
2002                 net->cc_mod.htcp_ca.lasttime = now;
2003                 return;
2004         }
2005
2006         net->cc_mod.htcp_ca.bytecount += net->net_ack;
2007         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)) &&
2008             (now - net->cc_mod.htcp_ca.lasttime >= net->cc_mod.htcp_ca.minRTT) &&
2009             (net->cc_mod.htcp_ca.minRTT > 0)) {
2010                 uint32_t cur_Bi = net->cc_mod.htcp_ca.bytecount/net->mtu*hz/(now - net->cc_mod.htcp_ca.lasttime);
2011
2012                 if (htcp_ccount(&net->cc_mod.htcp_ca) <= 3) {
2013                         /* just after backoff */
2014                         net->cc_mod.htcp_ca.minB = net->cc_mod.htcp_ca.maxB = net->cc_mod.htcp_ca.Bi = cur_Bi;
2015                 } else {
2016                         net->cc_mod.htcp_ca.Bi = (3*net->cc_mod.htcp_ca.Bi + cur_Bi)/4;
2017                         if (net->cc_mod.htcp_ca.Bi > net->cc_mod.htcp_ca.maxB)
2018                                 net->cc_mod.htcp_ca.maxB = net->cc_mod.htcp_ca.Bi;
2019                         if (net->cc_mod.htcp_ca.minB > net->cc_mod.htcp_ca.maxB)
2020                                 net->cc_mod.htcp_ca.minB = net->cc_mod.htcp_ca.maxB;
2021                 }
2022                 net->cc_mod.htcp_ca.bytecount = 0;
2023                 net->cc_mod.htcp_ca.lasttime = now;
2024         }
2025 }
2026
2027 static inline void
2028 htcp_beta_update(struct htcp *ca, uint32_t minRTT, uint32_t maxRTT)
2029 {
2030         if (use_bandwidth_switch) {
2031                 uint32_t maxB = ca->maxB;
2032                 uint32_t old_maxB = ca->old_maxB;
2033                 ca->old_maxB = ca->maxB;
2034
2035                 if (!between(5*maxB, 4*old_maxB, 6*old_maxB)) {
2036                         ca->beta = BETA_MIN;
2037                         ca->modeswitch = 0;
2038                         return;
2039                 }
2040         }
2041
2042         if (ca->modeswitch && minRTT > (uint32_t)MSEC_TO_TICKS(10) && maxRTT) {
2043                 ca->beta = (minRTT<<7)/maxRTT;
2044                 if (ca->beta < BETA_MIN)
2045                         ca->beta = BETA_MIN;
2046                 else if (ca->beta > BETA_MAX)
2047                         ca->beta = BETA_MAX;
2048         } else {
2049                 ca->beta = BETA_MIN;
2050                 ca->modeswitch = 1;
2051         }
2052 }
2053
2054 static inline void
2055 htcp_alpha_update(struct htcp *ca)
2056 {
2057         uint32_t minRTT = ca->minRTT;
2058         uint32_t factor = 1;
2059         uint32_t diff = htcp_cong_time(ca);
2060
2061         if (diff > (uint32_t)hz) {
2062                 diff -= hz;
2063                 factor = 1+ ( 10*diff + ((diff/2)*(diff/2)/hz))/hz;
2064         }
2065
2066         if (use_rtt_scaling && minRTT) {
2067                 uint32_t scale = (hz<<3)/(10*minRTT);
2068                 scale = min(max(scale, 1U<<2), 10U<<3); /* clamping ratio to interval [0.5,10]<<3 */
2069                 factor = (factor<<3)/scale;
2070                 if (!factor)
2071                         factor = 1;
2072         }
2073
2074         ca->alpha = 2*factor*((1<<7)-ca->beta);
2075         if (!ca->alpha)
2076                 ca->alpha = ALPHA_BASE;
2077 }
2078
2079 /* After we have the rtt data to calculate beta, we'd still prefer to wait one
2080  * rtt before we adjust our beta to ensure we are working from a consistent
2081  * data.
2082  *
2083  * This function should be called when we hit a congestion event since only at
2084  * that point do we really have a real sense of maxRTT (the queues en route
2085  * were getting just too full now).
2086  */
2087 static void
2088 htcp_param_update(struct sctp_nets *net)
2089 {
2090         uint32_t minRTT = net->cc_mod.htcp_ca.minRTT;
2091         uint32_t maxRTT = net->cc_mod.htcp_ca.maxRTT;
2092
2093         htcp_beta_update(&net->cc_mod.htcp_ca, minRTT, maxRTT);
2094         htcp_alpha_update(&net->cc_mod.htcp_ca);
2095
2096         /* add slowly fading memory for maxRTT to accommodate routing changes etc */
2097         if (minRTT > 0 && maxRTT > minRTT)
2098                 net->cc_mod.htcp_ca.maxRTT = minRTT + ((maxRTT-minRTT)*95)/100;
2099 }
2100
2101 static uint32_t
2102 htcp_recalc_ssthresh(struct sctp_nets *net)
2103 {
2104         htcp_param_update(net);
2105         return (max(((net->cwnd/net->mtu * net->cc_mod.htcp_ca.beta) >> 7)*net->mtu, 2U*net->mtu));
2106 }
2107
2108 static void
2109 htcp_cong_avoid(struct sctp_tcb *stcb, struct sctp_nets *net)
2110 {
2111         /*-
2112          * How to handle these functions?
2113          *      if (!tcp_is_cwnd_limited(sk, in_flight)) RRS - good question.
2114          *              return;
2115          */
2116         if (net->cwnd <= net->ssthresh) {
2117                 /* We are in slow start */
2118                 if (net->flight_size + net->net_ack >= net->cwnd) {
2119                         if (net->net_ack > (net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable))) {
2120                                 net->cwnd += (net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable));
2121                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2122                                         sctp_log_cwnd(stcb, net, net->mtu,
2123                                                 SCTP_CWND_LOG_FROM_SS);
2124                                 }
2125
2126                         } else {
2127                                 net->cwnd += net->net_ack;
2128                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2129                                         sctp_log_cwnd(stcb, net, net->net_ack,
2130                                                 SCTP_CWND_LOG_FROM_SS);
2131                                 }
2132
2133                         }
2134                 } else {
2135                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
2136                                 sctp_log_cwnd(stcb, net, net->net_ack,
2137                                         SCTP_CWND_LOG_NOADV_SS);
2138                         }
2139                 }
2140         } else {
2141                 measure_rtt(net);
2142
2143                 /* In dangerous area, increase slowly.
2144                  * In theory this is net->cwnd += alpha / net->cwnd
2145                  */
2146                 /* What is snd_cwnd_cnt?? */
2147                 if (((net->partial_bytes_acked/net->mtu * net->cc_mod.htcp_ca.alpha) >> 7)*net->mtu >= net->cwnd) {
2148                         /*-
2149                          * Does SCTP have a cwnd clamp?
2150                          * if (net->snd_cwnd < net->snd_cwnd_clamp) - Nope (RRS).
2151                          */
2152                         net->cwnd += net->mtu;
2153                         net->partial_bytes_acked = 0;
2154                         htcp_alpha_update(&net->cc_mod.htcp_ca);
2155                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2156                                 sctp_log_cwnd(stcb, net, net->mtu,
2157                                         SCTP_CWND_LOG_FROM_CA);
2158                         }
2159                 } else {
2160                         net->partial_bytes_acked += net->net_ack;
2161                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
2162                                 sctp_log_cwnd(stcb, net, net->net_ack,
2163                                         SCTP_CWND_LOG_NOADV_CA);
2164                         }
2165                 }
2166
2167                 net->cc_mod.htcp_ca.bytes_acked = net->mtu;
2168         }
2169 }
2170
2171 #ifdef SCTP_NOT_USED
2172 /* Lower bound on congestion window. */
2173 static uint32_t
2174 htcp_min_cwnd(struct sctp_tcb *stcb, struct sctp_nets *net)
2175 {
2176         return (net->ssthresh);
2177 }
2178 #endif
2179
2180 static void
2181 htcp_init(struct sctp_nets *net)
2182 {
2183         memset(&net->cc_mod.htcp_ca, 0, sizeof(struct htcp));
2184         net->cc_mod.htcp_ca.alpha = ALPHA_BASE;
2185         net->cc_mod.htcp_ca.beta = BETA_MIN;
2186         net->cc_mod.htcp_ca.bytes_acked = net->mtu;
2187         net->cc_mod.htcp_ca.last_cong = sctp_get_tick_count();
2188 }
2189
2190 static void
2191 sctp_htcp_set_initial_cc_param(struct sctp_tcb *stcb, struct sctp_nets *net)
2192 {
2193         /*
2194          * We take the max of the burst limit times a MTU or the
2195          * INITIAL_CWND. We then limit this to 4 MTU's of sending.
2196          */
2197         net->cwnd = min((net->mtu * 4), max((2 * net->mtu), SCTP_INITIAL_CWND));
2198         net->ssthresh = stcb->asoc.peers_rwnd;
2199         htcp_init(net);
2200
2201         if (SCTP_BASE_SYSCTL(sctp_logging_level) & (SCTP_CWND_MONITOR_ENABLE|SCTP_CWND_LOGGING_ENABLE)) {
2202                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_INITIALIZATION);
2203         }
2204 }
2205
2206 static void
2207 sctp_htcp_cwnd_update_after_sack(struct sctp_tcb *stcb,
2208                  struct sctp_association *asoc,
2209                  int accum_moved, int reneged_all SCTP_UNUSED, int will_exit)
2210 {
2211         struct sctp_nets *net;
2212
2213         /******************************/
2214         /* update cwnd and Early FR   */
2215         /******************************/
2216         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
2217
2218 #ifdef JANA_CMT_FAST_RECOVERY
2219                 /*
2220                  * CMT fast recovery code. Need to debug.
2221                  */
2222                 if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
2223                         if (SCTP_TSN_GE(asoc->last_acked_seq, net->fast_recovery_tsn) ||
2224                             SCTP_TSN_GE(net->pseudo_cumack,net->fast_recovery_tsn)) {
2225                                 net->will_exit_fast_recovery = 1;
2226                         }
2227                 }
2228 #endif
2229                 /* if nothing was acked on this destination skip it */
2230                 if (net->net_ack == 0) {
2231                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
2232                                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
2233                         }
2234                         continue;
2235                 }
2236 #ifdef JANA_CMT_FAST_RECOVERY
2237                 /* CMT fast recovery code
2238                  */
2239                 /*
2240                 if (sctp_cmt_on_off > 0 && net->fast_retran_loss_recovery && net->will_exit_fast_recovery == 0) {
2241                     @@@ Do something
2242                  }
2243                  else if (sctp_cmt_on_off == 0 && asoc->fast_retran_loss_recovery && will_exit == 0) {
2244                 */
2245 #endif
2246
2247                 if (asoc->fast_retran_loss_recovery &&
2248                     will_exit == 0 &&
2249                     (asoc->sctp_cmt_on_off == 0)) {
2250                         /*
2251                          * If we are in loss recovery we skip any cwnd
2252                          * update
2253                          */
2254                         return;
2255                 }
2256                 /*
2257                  * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
2258                  * moved.
2259                  */
2260                 if (accum_moved ||
2261                     ((asoc->sctp_cmt_on_off > 0) && net->new_pseudo_cumack)) {
2262                         htcp_cong_avoid(stcb, net);
2263                         measure_achieved_throughput(net);
2264                 } else {
2265                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
2266                                 sctp_log_cwnd(stcb, net, net->mtu,
2267                                         SCTP_CWND_LOG_NO_CUMACK);
2268                         }
2269                 }
2270         }
2271 }
2272
2273 static void
2274 sctp_htcp_cwnd_update_after_fr(struct sctp_tcb *stcb,
2275                 struct sctp_association *asoc)
2276 {
2277         struct sctp_nets *net;
2278                 /*
2279          * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off > 0) &&
2280          * (net->fast_retran_loss_recovery == 0)))
2281          */
2282         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
2283                 if ((asoc->fast_retran_loss_recovery == 0) ||
2284                     (asoc->sctp_cmt_on_off > 0)) {
2285                         /* out of a RFC2582 Fast recovery window? */
2286                         if (net->net_ack > 0) {
2287                                 /*
2288                                  * per section 7.2.3, are there any
2289                                  * destinations that had a fast retransmit
2290                                  * to them. If so what we need to do is
2291                                  * adjust ssthresh and cwnd.
2292                                  */
2293                                 struct sctp_tmit_chunk *lchk;
2294                                 int old_cwnd = net->cwnd;
2295
2296                                 /* JRS - reset as if state were changed */
2297                                 htcp_reset(&net->cc_mod.htcp_ca);
2298                                 net->ssthresh = htcp_recalc_ssthresh(net);
2299                                 net->cwnd = net->ssthresh;
2300                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2301                                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
2302                                                 SCTP_CWND_LOG_FROM_FR);
2303                                 }
2304                                 lchk = TAILQ_FIRST(&asoc->send_queue);
2305
2306                                 net->partial_bytes_acked = 0;
2307                                 /* Turn on fast recovery window */
2308                                 asoc->fast_retran_loss_recovery = 1;
2309                                 if (lchk == NULL) {
2310                                         /* Mark end of the window */
2311                                         asoc->fast_recovery_tsn = asoc->sending_seq - 1;
2312                                 } else {
2313                                         asoc->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
2314                                 }
2315
2316                                 /*
2317                                  * CMT fast recovery -- per destination
2318                                  * recovery variable.
2319                                  */
2320                                 net->fast_retran_loss_recovery = 1;
2321
2322                                 if (lchk == NULL) {
2323                                         /* Mark end of the window */
2324                                         net->fast_recovery_tsn = asoc->sending_seq - 1;
2325                                 } else {
2326                                         net->fast_recovery_tsn = lchk->rec.data.TSN_seq - 1;
2327                                 }
2328
2329                                 sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
2330                                                 stcb->sctp_ep, stcb, net, SCTP_FROM_SCTP_INDATA+SCTP_LOC_32);
2331                                 sctp_timer_start(SCTP_TIMER_TYPE_SEND,
2332                                                  stcb->sctp_ep, stcb, net);
2333                         }
2334                 } else if (net->net_ack > 0) {
2335                         /*
2336                          * Mark a peg that we WOULD have done a cwnd
2337                          * reduction but RFC2582 prevented this action.
2338                          */
2339                         SCTP_STAT_INCR(sctps_fastretransinrtt);
2340                 }
2341         }
2342 }
2343
2344 static void
2345 sctp_htcp_cwnd_update_after_timeout(struct sctp_tcb *stcb,
2346         struct sctp_nets *net)
2347 {
2348                 int old_cwnd = net->cwnd;
2349
2350                 /* JRS - reset as if the state were being changed to timeout */
2351                 htcp_reset(&net->cc_mod.htcp_ca);
2352                 net->ssthresh = htcp_recalc_ssthresh(net);
2353                 net->cwnd = net->mtu;
2354                 net->partial_bytes_acked = 0;
2355                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2356                         sctp_log_cwnd(stcb, net, net->cwnd - old_cwnd, SCTP_CWND_LOG_FROM_RTX);
2357                 }
2358 }
2359
2360 static void
2361 sctp_htcp_cwnd_update_after_ecn_echo(struct sctp_tcb *stcb,
2362                 struct sctp_nets *net, int in_window, int num_pkt_lost SCTP_UNUSED)
2363 {
2364         int old_cwnd;
2365         old_cwnd = net->cwnd;
2366
2367         /* JRS - reset hctp as if state changed */
2368         if (in_window == 0) {
2369                 htcp_reset(&net->cc_mod.htcp_ca);
2370                 SCTP_STAT_INCR(sctps_ecnereducedcwnd);
2371                 net->ssthresh = htcp_recalc_ssthresh(net);
2372                 if (net->ssthresh < net->mtu) {
2373                         net->ssthresh = net->mtu;
2374                         /* here back off the timer as well, to slow us down */
2375                         net->RTO <<= 1;
2376                 }
2377                 net->cwnd = net->ssthresh;
2378                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2379                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
2380                 }
2381         }
2382 }
2383
2384 struct sctp_cc_functions sctp_cc_functions[] = {
2385 {
2386 #if defined(__Windows__) || defined(__Userspace_os_Windows)
2387         sctp_set_initial_cc_param,
2388         sctp_cwnd_update_after_sack,
2389         sctp_cwnd_update_exit_pf_common,
2390         sctp_cwnd_update_after_fr,
2391         sctp_cwnd_update_after_timeout,
2392         sctp_cwnd_update_after_ecn_echo,
2393         sctp_cwnd_update_after_packet_dropped,
2394         sctp_cwnd_update_after_output,
2395 #else
2396         .sctp_set_initial_cc_param = sctp_set_initial_cc_param,
2397         .sctp_cwnd_update_after_sack = sctp_cwnd_update_after_sack,
2398         .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
2399         .sctp_cwnd_update_after_fr = sctp_cwnd_update_after_fr,
2400         .sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
2401         .sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_after_ecn_echo,
2402         .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
2403         .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
2404 #endif
2405 },
2406 {
2407 #if defined(__Windows__) || defined(__Userspace_os_Windows)
2408         sctp_set_initial_cc_param,
2409         sctp_hs_cwnd_update_after_sack,
2410         sctp_cwnd_update_exit_pf_common,
2411         sctp_hs_cwnd_update_after_fr,
2412         sctp_cwnd_update_after_timeout,
2413         sctp_cwnd_update_after_ecn_echo,
2414         sctp_cwnd_update_after_packet_dropped,
2415         sctp_cwnd_update_after_output,
2416 #else
2417         .sctp_set_initial_cc_param = sctp_set_initial_cc_param,
2418         .sctp_cwnd_update_after_sack = sctp_hs_cwnd_update_after_sack,
2419         .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
2420         .sctp_cwnd_update_after_fr = sctp_hs_cwnd_update_after_fr,
2421         .sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
2422         .sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_after_ecn_echo,
2423         .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
2424         .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
2425 #endif
2426 },
2427 {
2428 #if defined(__Windows__) || defined(__Userspace_os_Windows)
2429         sctp_htcp_set_initial_cc_param,
2430         sctp_htcp_cwnd_update_after_sack,
2431         sctp_cwnd_update_exit_pf_common,
2432         sctp_htcp_cwnd_update_after_fr,
2433         sctp_htcp_cwnd_update_after_timeout,
2434         sctp_htcp_cwnd_update_after_ecn_echo,
2435         sctp_cwnd_update_after_packet_dropped,
2436         sctp_cwnd_update_after_output,
2437 #else
2438         .sctp_set_initial_cc_param = sctp_htcp_set_initial_cc_param,
2439         .sctp_cwnd_update_after_sack = sctp_htcp_cwnd_update_after_sack,
2440         .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
2441         .sctp_cwnd_update_after_fr = sctp_htcp_cwnd_update_after_fr,
2442         .sctp_cwnd_update_after_timeout = sctp_htcp_cwnd_update_after_timeout,
2443         .sctp_cwnd_update_after_ecn_echo = sctp_htcp_cwnd_update_after_ecn_echo,
2444         .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
2445         .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
2446 #endif
2447 },
2448 {
2449 #if defined(__Windows__) || defined(__Userspace_os_Windows)
2450         sctp_set_rtcc_initial_cc_param,
2451         sctp_cwnd_update_rtcc_after_sack,
2452         sctp_cwnd_update_exit_pf_common,
2453         sctp_cwnd_update_after_fr,
2454         sctp_cwnd_update_after_timeout,
2455         sctp_cwnd_update_rtcc_after_ecn_echo,
2456         sctp_cwnd_update_after_packet_dropped,
2457         sctp_cwnd_update_after_output,
2458         sctp_cwnd_update_rtcc_packet_transmitted,
2459         sctp_cwnd_update_rtcc_tsn_acknowledged,
2460         sctp_cwnd_new_rtcc_transmission_begins,
2461         sctp_cwnd_prepare_rtcc_net_for_sack,
2462         sctp_cwnd_rtcc_socket_option,
2463         sctp_rtt_rtcc_calculated
2464 #else
2465         .sctp_set_initial_cc_param = sctp_set_rtcc_initial_cc_param,
2466         .sctp_cwnd_update_after_sack = sctp_cwnd_update_rtcc_after_sack,
2467         .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
2468         .sctp_cwnd_update_after_fr = sctp_cwnd_update_after_fr,
2469         .sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
2470         .sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_rtcc_after_ecn_echo,
2471         .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
2472         .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
2473         .sctp_cwnd_update_packet_transmitted = sctp_cwnd_update_rtcc_packet_transmitted,
2474         .sctp_cwnd_update_tsn_acknowledged = sctp_cwnd_update_rtcc_tsn_acknowledged,
2475         .sctp_cwnd_new_transmission_begins = sctp_cwnd_new_rtcc_transmission_begins,
2476         .sctp_cwnd_prepare_net_for_sack = sctp_cwnd_prepare_rtcc_net_for_sack,
2477         .sctp_cwnd_socket_option = sctp_cwnd_rtcc_socket_option,
2478         .sctp_rtt_calculated = sctp_rtt_rtcc_calculated
2479 #endif
2480 }
2481 };