sys/netinet/sctp_cc_functions.c

   1 /*-
   2  * Copyright (c) 2001-2007, by Cisco Systems, Inc. All rights reserved.
   3  * Copyright (c) 2008-2012, by Randall Stewart. All rights reserved.
   4  * Copyright (c) 2008-2012, by Michael Tuexen. All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions are met:
   8  *
   9  * a) Redistributions of source code must retain the above copyright notice,
  10  *    this list of conditions and the following disclaimer.
  11  *
  12  * b) Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in
  14  *    the documentation and/or other materials provided with the distribution.
  15  *
  16  * c) Neither the name of Cisco Systems, Inc. nor the names of its
  17  *    contributors may be used to endorse or promote products derived
  18  *    from this software without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  21  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  22  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  24  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  30  * THE POSSIBILITY OF SUCH DAMAGE.
  31  */
  32
  33 #include <sys/cdefs.h>
  34 __FBSDID("$FreeBSD$");
  35
  36 #include <netinet/sctp_os.h>
  37 #include <netinet/sctp_var.h>
  38 #include <netinet/sctp_sysctl.h>
  39 #include <netinet/sctp_pcb.h>
  40 #include <netinet/sctp_header.h>
  41 #include <netinet/sctputil.h>
  42 #include <netinet/sctp_output.h>
  43 #include <netinet/sctp_input.h>
  44 #include <netinet/sctp_indata.h>
  45 #include <netinet/sctp_uio.h>
  46 #include <netinet/sctp_timer.h>
  47 #include <netinet/sctp_auth.h>
  48 #include <netinet/sctp_asconf.h>
  49 #include <netinet/sctp_dtrace_declare.h>
  50
  51 #define SHIFT_MPTCP_MULTI_N 40
  52 #define SHIFT_MPTCP_MULTI_Z 16
  53 #define SHIFT_MPTCP_MULTI 8
  54
  55 static void
  56 sctp_enforce_cwnd_limit(struct sctp_association *assoc, struct sctp_nets *net)
  57 {
  58         if ((assoc->max_cwnd > 0) &&
  59             (net->cwnd > assoc->max_cwnd) &&
  60             (net->cwnd > (net->mtu - sizeof(struct sctphdr)))) {
  61                 net->cwnd = assoc->max_cwnd;
  62                 if (net->cwnd < (net->mtu - sizeof(struct sctphdr))) {
  63                         net->cwnd = net->mtu - sizeof(struct sctphdr);
  64                 }
  65         }
  66 }
  67
  68 static void
  69 sctp_set_initial_cc_param(struct sctp_tcb *stcb, struct sctp_nets *net)
  70 {
  71         struct sctp_association *assoc;
  72         uint32_t cwnd_in_mtu;
  73
  74         assoc = &stcb->asoc;
  75         cwnd_in_mtu = SCTP_BASE_SYSCTL(sctp_initial_cwnd);
  76         if (cwnd_in_mtu == 0) {
  77                 /* Using 0 means that the value of RFC 4960 is used. */
  78                 net->cwnd = min((net->mtu * 4), max((2 * net->mtu), SCTP_INITIAL_CWND));
  79         } else {
  80                 /*
  81                  * We take the minimum of the burst limit and the initial
  82                  * congestion window.
  83                  */
  84                 if ((assoc->max_burst > 0) && (cwnd_in_mtu > assoc->max_burst))
  85                         cwnd_in_mtu = assoc->max_burst;
  86                 net->cwnd = (net->mtu - sizeof(struct sctphdr)) * cwnd_in_mtu;
  87         }
  88         if ((stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) ||
  89             (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV2)) {
  90                 /* In case of resource pooling initialize appropriately */
  91                 net->cwnd /= assoc->numnets;
  92                 if (net->cwnd < (net->mtu - sizeof(struct sctphdr))) {
  93                         net->cwnd = net->mtu - sizeof(struct sctphdr);
  94                 }
  95         }
  96         sctp_enforce_cwnd_limit(assoc, net);
  97         net->ssthresh = assoc->peers_rwnd;
  98         SDT_PROBE5(sctp, cwnd, net, init,
  99             stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
 100             0, net->cwnd);
 101         if (SCTP_BASE_SYSCTL(sctp_logging_level) &
 102             (SCTP_CWND_MONITOR_ENABLE | SCTP_CWND_LOGGING_ENABLE)) {
 103                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_INITIALIZATION);
 104         }
 105 }
 106
 107 static void
 108 sctp_cwnd_update_after_fr(struct sctp_tcb *stcb,
 109     struct sctp_association *asoc)
 110 {
 111         struct sctp_nets *net;
 112         uint32_t t_ssthresh, t_cwnd;
 113         uint64_t t_ucwnd_sbw;
 114
 115         /* MT FIXME: Don't compute this over and over again */
 116         t_ssthresh = 0;
 117         t_cwnd = 0;
 118         t_ucwnd_sbw = 0;
 119         if ((asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) ||
 120             (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2)) {
 121                 TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
 122                         t_ssthresh += net->ssthresh;
 123                         t_cwnd += net->cwnd;
 124                         if (net->lastsa > 0) {
 125                                 t_ucwnd_sbw += (uint64_t)net->cwnd / (uint64_t)net->lastsa;
 126                         }
 127                 }
 128                 if (t_ucwnd_sbw == 0) {
 129                         t_ucwnd_sbw = 1;
 130                 }
 131         }
 132
 133         /*-
 134          * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off > 0) &&
 135          * (net->fast_retran_loss_recovery == 0)))
 136          */
 137         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
 138                 if ((asoc->fast_retran_loss_recovery == 0) ||
 139                     (asoc->sctp_cmt_on_off > 0)) {
 140                         /* out of a RFC2582 Fast recovery window? */
 141                         if (net->net_ack > 0) {
 142                                 /*
 143                                  * per section 7.2.3, are there any
 144                                  * destinations that had a fast retransmit
 145                                  * to them. If so what we need to do is
 146                                  * adjust ssthresh and cwnd.
 147                                  */
 148                                 struct sctp_tmit_chunk *lchk;
 149                                 int old_cwnd = net->cwnd;
 150
 151                                 if ((asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) ||
 152                                     (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2)) {
 153                                         if (asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) {
 154                                                 net->ssthresh = (uint32_t)(((uint64_t)4 *
 155                                                     (uint64_t)net->mtu *
 156                                                     (uint64_t)net->ssthresh) /
 157                                                     (uint64_t)t_ssthresh);
 158
 159                                         }
 160                                         if (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2) {
 161                                                 uint32_t srtt;
 162
 163                                                 srtt = net->lastsa;
 164                                                 /*
 165                                                  * lastsa>>3;  we don't need
 166                                                  * to devide ...
 167                                                  */
 168                                                 if (srtt == 0) {
 169                                                         srtt = 1;
 170                                                 }
 171                                                 /*
 172                                                  * Short Version => Equal to
 173                                                  * Contel Version MBe
 174                                                  */
 175                                                 net->ssthresh = (uint32_t)(((uint64_t)4 *
 176                                                     (uint64_t)net->mtu *
 177                                                     (uint64_t)net->cwnd) /
 178                                                     ((uint64_t)srtt *
 179                                                     t_ucwnd_sbw));
 180                                                  /* INCREASE FACTOR */ ;
 181                                         }
 182                                         if ((net->cwnd > t_cwnd / 2) &&
 183                                             (net->ssthresh < net->cwnd - t_cwnd / 2)) {
 184                                                 net->ssthresh = net->cwnd - t_cwnd / 2;
 185                                         }
 186                                         if (net->ssthresh < net->mtu) {
 187                                                 net->ssthresh = net->mtu;
 188                                         }
 189                                 } else {
 190                                         net->ssthresh = net->cwnd / 2;
 191                                         if (net->ssthresh < (net->mtu * 2)) {
 192                                                 net->ssthresh = 2 * net->mtu;
 193                                         }
 194                                 }
 195                                 net->cwnd = net->ssthresh;
 196                                 sctp_enforce_cwnd_limit(asoc, net);
 197                                 SDT_PROBE5(sctp, cwnd, net, fr,
 198                                     stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
 199                                     old_cwnd, net->cwnd);
 200                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 201                                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
 202                                             SCTP_CWND_LOG_FROM_FR);
 203                                 }
 204                                 lchk = TAILQ_FIRST(&asoc->send_queue);
 205
 206                                 net->partial_bytes_acked = 0;
 207                                 /* Turn on fast recovery window */
 208                                 asoc->fast_retran_loss_recovery = 1;
 209                                 if (lchk == NULL) {
 210                                         /* Mark end of the window */
 211                                         asoc->fast_recovery_tsn = asoc->sending_seq - 1;
 212                                 } else {
 213                                         asoc->fast_recovery_tsn = lchk->rec.data.tsn - 1;
 214                                 }
 215
 216                                 /*
 217                                  * CMT fast recovery -- per destination
 218                                  * recovery variable.
 219                                  */
 220                                 net->fast_retran_loss_recovery = 1;
 221
 222                                 if (lchk == NULL) {
 223                                         /* Mark end of the window */
 224                                         net->fast_recovery_tsn = asoc->sending_seq - 1;
 225                                 } else {
 226                                         net->fast_recovery_tsn = lchk->rec.data.tsn - 1;
 227                                 }
 228
 229                                 sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
 230                                     stcb->sctp_ep, stcb, net,
 231                                     SCTP_FROM_SCTP_CC_FUNCTIONS + SCTP_LOC_1);
 232                                 sctp_timer_start(SCTP_TIMER_TYPE_SEND,
 233                                     stcb->sctp_ep, stcb, net);
 234                         }
 235                 } else if (net->net_ack > 0) {
 236                         /*
 237                          * Mark a peg that we WOULD have done a cwnd
 238                          * reduction but RFC2582 prevented this action.
 239                          */
 240                         SCTP_STAT_INCR(sctps_fastretransinrtt);
 241                 }
 242         }
 243 }
 244
 245 /* Defines for instantaneous bw decisions */
 246 #define SCTP_INST_LOOSING 1     /* Losing to other flows */
 247 #define SCTP_INST_NEUTRAL 2     /* Neutral, no indication */
 248 #define SCTP_INST_GAINING 3     /* Gaining, step down possible */
 249
 250
 251 static int
 252 cc_bw_same(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw,
 253     uint64_t rtt_offset, uint64_t vtag, uint8_t inst_ind)
 254 {
 255         uint64_t oth, probepoint;
 256
 257         probepoint = (((uint64_t)net->cwnd) << 32);
 258         if (net->rtt > net->cc_mod.rtcc.lbw_rtt + rtt_offset) {
 259                 /*
 260                  * rtt increased we don't update bw.. so we don't update the
 261                  * rtt either.
 262                  */
 263                 /* Probe point 5 */
 264                 probepoint |= ((5 << 16) | 1);
 265                 SDT_PROBE5(sctp, cwnd, net, rttvar,
 266                     vtag,
 267                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 268                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 269                     net->flight_size,
 270                     probepoint);
 271                 if ((net->cc_mod.rtcc.steady_step) && (inst_ind != SCTP_INST_LOOSING)) {
 272                         if (net->cc_mod.rtcc.last_step_state == 5)
 273                                 net->cc_mod.rtcc.step_cnt++;
 274                         else
 275                                 net->cc_mod.rtcc.step_cnt = 1;
 276                         net->cc_mod.rtcc.last_step_state = 5;
 277                         if ((net->cc_mod.rtcc.step_cnt == net->cc_mod.rtcc.steady_step) ||
 278                             ((net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step) &&
 279                             ((net->cc_mod.rtcc.step_cnt % net->cc_mod.rtcc.steady_step) == 0))) {
 280                                 /* Try a step down */
 281                                 oth = net->cc_mod.rtcc.vol_reduce;
 282                                 oth <<= 16;
 283                                 oth |= net->cc_mod.rtcc.step_cnt;
 284                                 oth <<= 16;
 285                                 oth |= net->cc_mod.rtcc.last_step_state;
 286                                 SDT_PROBE5(sctp, cwnd, net, rttstep,
 287                                     vtag,
 288                                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 289                                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 290                                     oth,
 291                                     probepoint);
 292                                 if (net->cwnd > (4 * net->mtu)) {
 293                                         net->cwnd -= net->mtu;
 294                                         net->cc_mod.rtcc.vol_reduce++;
 295                                 } else {
 296                                         net->cc_mod.rtcc.step_cnt = 0;
 297                                 }
 298                         }
 299                 }
 300                 return (1);
 301         }
 302         if (net->rtt < net->cc_mod.rtcc.lbw_rtt - rtt_offset) {
 303                 /*
 304                  * rtt decreased, there could be more room. we update both
 305                  * the bw and the rtt here to lock this in as a good step
 306                  * down.
 307                  */
 308                 /* Probe point 6 */
 309                 probepoint |= ((6 << 16) | 0);
 310                 SDT_PROBE5(sctp, cwnd, net, rttvar,
 311                     vtag,
 312                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 313                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 314                     net->flight_size,
 315                     probepoint);
 316                 if (net->cc_mod.rtcc.steady_step) {
 317                         oth = net->cc_mod.rtcc.vol_reduce;
 318                         oth <<= 16;
 319                         oth |= net->cc_mod.rtcc.step_cnt;
 320                         oth <<= 16;
 321                         oth |= net->cc_mod.rtcc.last_step_state;
 322                         SDT_PROBE5(sctp, cwnd, net, rttstep,
 323                             vtag,
 324                             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 325                             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 326                             oth,
 327                             probepoint);
 328                         if ((net->cc_mod.rtcc.last_step_state == 5) &&
 329                             (net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step)) {
 330                                 /* Step down worked */
 331                                 net->cc_mod.rtcc.step_cnt = 0;
 332                                 return (1);
 333                         } else {
 334                                 net->cc_mod.rtcc.last_step_state = 6;
 335                                 net->cc_mod.rtcc.step_cnt = 0;
 336                         }
 337                 }
 338                 net->cc_mod.rtcc.lbw = nbw;
 339                 net->cc_mod.rtcc.lbw_rtt = net->rtt;
 340                 net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
 341                 if (inst_ind == SCTP_INST_GAINING)
 342                         return (1);
 343                 else if (inst_ind == SCTP_INST_NEUTRAL)
 344                         return (1);
 345                 else
 346                         return (0);
 347         }
 348         /*
 349          * Ok bw and rtt remained the same .. no update to any
 350          */
 351         /* Probe point 7 */
 352         probepoint |= ((7 << 16) | net->cc_mod.rtcc.ret_from_eq);
 353         SDT_PROBE5(sctp, cwnd, net, rttvar,
 354             vtag,
 355             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 356             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 357             net->flight_size,
 358             probepoint);
 359         if ((net->cc_mod.rtcc.steady_step) && (inst_ind != SCTP_INST_LOOSING)) {
 360                 if (net->cc_mod.rtcc.last_step_state == 5)
 361                         net->cc_mod.rtcc.step_cnt++;
 362                 else
 363                         net->cc_mod.rtcc.step_cnt = 1;
 364                 net->cc_mod.rtcc.last_step_state = 5;
 365                 if ((net->cc_mod.rtcc.step_cnt == net->cc_mod.rtcc.steady_step) ||
 366                     ((net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step) &&
 367                     ((net->cc_mod.rtcc.step_cnt % net->cc_mod.rtcc.steady_step) == 0))) {
 368                         /* Try a step down */
 369                         if (net->cwnd > (4 * net->mtu)) {
 370                                 net->cwnd -= net->mtu;
 371                                 net->cc_mod.rtcc.vol_reduce++;
 372                                 return (1);
 373                         } else {
 374                                 net->cc_mod.rtcc.step_cnt = 0;
 375                         }
 376                 }
 377         }
 378         if (inst_ind == SCTP_INST_GAINING)
 379                 return (1);
 380         else if (inst_ind == SCTP_INST_NEUTRAL)
 381                 return (1);
 382         else
 383                 return ((int)net->cc_mod.rtcc.ret_from_eq);
 384 }
 385
 386 static int
 387 cc_bw_decrease(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw, uint64_t rtt_offset,
 388     uint64_t vtag, uint8_t inst_ind)
 389 {
 390         uint64_t oth, probepoint;
 391
 392         /* Bandwidth decreased. */
 393         probepoint = (((uint64_t)net->cwnd) << 32);
 394         if (net->rtt > net->cc_mod.rtcc.lbw_rtt + rtt_offset) {
 395                 /* rtt increased */
 396                 /* Did we add more */
 397                 if ((net->cwnd > net->cc_mod.rtcc.cwnd_at_bw_set) &&
 398                     (inst_ind != SCTP_INST_LOOSING)) {
 399                         /* We caused it maybe.. back off? */
 400                         /* PROBE POINT 1 */
 401                         probepoint |= ((1 << 16) | 1);
 402                         SDT_PROBE5(sctp, cwnd, net, rttvar,
 403                             vtag,
 404                             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 405                             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 406                             net->flight_size,
 407                             probepoint);
 408                         if (net->cc_mod.rtcc.ret_from_eq) {
 409                                 /*
 410                                  * Switch over to CA if we are less
 411                                  * aggressive
 412                                  */
 413                                 net->ssthresh = net->cwnd - 1;
 414                                 net->partial_bytes_acked = 0;
 415                         }
 416                         return (1);
 417                 }
 418                 /* Probe point 2 */
 419                 probepoint |= ((2 << 16) | 0);
 420                 SDT_PROBE5(sctp, cwnd, net, rttvar,
 421                     vtag,
 422                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 423                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 424                     net->flight_size,
 425                     probepoint);
 426                 /* Someone else - fight for more? */
 427                 if (net->cc_mod.rtcc.steady_step) {
 428                         oth = net->cc_mod.rtcc.vol_reduce;
 429                         oth <<= 16;
 430                         oth |= net->cc_mod.rtcc.step_cnt;
 431                         oth <<= 16;
 432                         oth |= net->cc_mod.rtcc.last_step_state;
 433                         SDT_PROBE5(sctp, cwnd, net, rttstep,
 434                             vtag,
 435                             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 436                             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 437                             oth,
 438                             probepoint);
 439                         /*
 440                          * Did we voluntarily give up some? if so take one
 441                          * back please
 442                          */
 443                         if ((net->cc_mod.rtcc.vol_reduce) &&
 444                             (inst_ind != SCTP_INST_GAINING)) {
 445                                 net->cwnd += net->mtu;
 446                                 sctp_enforce_cwnd_limit(&stcb->asoc, net);
 447                                 net->cc_mod.rtcc.vol_reduce--;
 448                         }
 449                         net->cc_mod.rtcc.last_step_state = 2;
 450                         net->cc_mod.rtcc.step_cnt = 0;
 451                 }
 452                 goto out_decision;
 453         } else if (net->rtt < net->cc_mod.rtcc.lbw_rtt - rtt_offset) {
 454                 /* bw & rtt decreased */
 455                 /* Probe point 3 */
 456                 probepoint |= ((3 << 16) | 0);
 457                 SDT_PROBE5(sctp, cwnd, net, rttvar,
 458                     vtag,
 459                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 460                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 461                     net->flight_size,
 462                     probepoint);
 463                 if (net->cc_mod.rtcc.steady_step) {
 464                         oth = net->cc_mod.rtcc.vol_reduce;
 465                         oth <<= 16;
 466                         oth |= net->cc_mod.rtcc.step_cnt;
 467                         oth <<= 16;
 468                         oth |= net->cc_mod.rtcc.last_step_state;
 469                         SDT_PROBE5(sctp, cwnd, net, rttstep,
 470                             vtag,
 471                             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 472                             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 473                             oth,
 474                             probepoint);
 475                         if ((net->cc_mod.rtcc.vol_reduce) &&
 476                             (inst_ind != SCTP_INST_GAINING)) {
 477                                 net->cwnd += net->mtu;
 478                                 sctp_enforce_cwnd_limit(&stcb->asoc, net);
 479                                 net->cc_mod.rtcc.vol_reduce--;
 480                         }
 481                         net->cc_mod.rtcc.last_step_state = 3;
 482                         net->cc_mod.rtcc.step_cnt = 0;
 483                 }
 484                 goto out_decision;
 485         }
 486         /* The bw decreased but rtt stayed the same */
 487         /* Probe point 4 */
 488         probepoint |= ((4 << 16) | 0);
 489         SDT_PROBE5(sctp, cwnd, net, rttvar,
 490             vtag,
 491             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 492             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 493             net->flight_size,
 494             probepoint);
 495         if (net->cc_mod.rtcc.steady_step) {
 496                 oth = net->cc_mod.rtcc.vol_reduce;
 497                 oth <<= 16;
 498                 oth |= net->cc_mod.rtcc.step_cnt;
 499                 oth <<= 16;
 500                 oth |= net->cc_mod.rtcc.last_step_state;
 501                 SDT_PROBE5(sctp, cwnd, net, rttstep,
 502                     vtag,
 503                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 504                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 505                     oth,
 506                     probepoint);
 507                 if ((net->cc_mod.rtcc.vol_reduce) &&
 508                     (inst_ind != SCTP_INST_GAINING)) {
 509                         net->cwnd += net->mtu;
 510                         sctp_enforce_cwnd_limit(&stcb->asoc, net);
 511                         net->cc_mod.rtcc.vol_reduce--;
 512                 }
 513                 net->cc_mod.rtcc.last_step_state = 4;
 514                 net->cc_mod.rtcc.step_cnt = 0;
 515         }
 516 out_decision:
 517         net->cc_mod.rtcc.lbw = nbw;
 518         net->cc_mod.rtcc.lbw_rtt = net->rtt;
 519         net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
 520         if (inst_ind == SCTP_INST_GAINING) {
 521                 return (1);
 522         } else {
 523                 return (0);
 524         }
 525 }
 526
 527 static int
 528 cc_bw_increase(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw, uint64_t vtag)
 529 {
 530         uint64_t oth, probepoint;
 531
 532         /*
 533          * BW increased, so update and return 0, since all actions in our
 534          * table say to do the normal CC update. Note that we pay no
 535          * attention to the inst_ind since our overall sum is increasing.
 536          */
 537         /* PROBE POINT 0 */
 538         probepoint = (((uint64_t)net->cwnd) << 32);
 539         SDT_PROBE5(sctp, cwnd, net, rttvar,
 540             vtag,
 541             ((net->cc_mod.rtcc.lbw << 32) | nbw),
 542             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 543             net->flight_size,
 544             probepoint);
 545         if (net->cc_mod.rtcc.steady_step) {
 546                 oth = net->cc_mod.rtcc.vol_reduce;
 547                 oth <<= 16;
 548                 oth |= net->cc_mod.rtcc.step_cnt;
 549                 oth <<= 16;
 550                 oth |= net->cc_mod.rtcc.last_step_state;
 551                 SDT_PROBE5(sctp, cwnd, net, rttstep,
 552                     vtag,
 553                     ((net->cc_mod.rtcc.lbw << 32) | nbw),
 554                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 555                     oth,
 556                     probepoint);
 557                 net->cc_mod.rtcc.last_step_state = 0;
 558                 net->cc_mod.rtcc.step_cnt = 0;
 559                 net->cc_mod.rtcc.vol_reduce = 0;
 560         }
 561         net->cc_mod.rtcc.lbw = nbw;
 562         net->cc_mod.rtcc.lbw_rtt = net->rtt;
 563         net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
 564         return (0);
 565 }
 566
 567 /* RTCC Algorithm to limit growth of cwnd, return
 568  * true if you want to NOT allow cwnd growth
 569  */
 570 static int
 571 cc_bw_limit(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw)
 572 {
 573         uint64_t bw_offset, rtt_offset;
 574         uint64_t probepoint, rtt, vtag;
 575         uint64_t bytes_for_this_rtt, inst_bw;
 576         uint64_t div, inst_off;
 577         int bw_shift;
 578         uint8_t inst_ind;
 579         int ret;
 580
 581         /*-
 582          * Here we need to see if we want
 583          * to limit cwnd growth due to increase
 584          * in overall rtt but no increase in bw.
 585          * We use the following table to figure
 586          * out what we should do. When we return
 587          * 0, cc update goes on as planned. If we
 588          * return 1, then no cc update happens and cwnd
 589          * stays where it is at.
 590          * ----------------------------------
 591          *   BW    |    RTT   | Action
 592          * *********************************
 593          *   INC   |    INC   | return 0
 594          * ----------------------------------
 595          *   INC   |    SAME  | return 0
 596          * ----------------------------------
 597          *   INC   |    DECR  | return 0
 598          * ----------------------------------
 599          *   SAME  |    INC   | return 1
 600          * ----------------------------------
 601          *   SAME  |    SAME  | return 1
 602          * ----------------------------------
 603          *   SAME  |    DECR  | return 0
 604          * ----------------------------------
 605          *   DECR  |    INC   | return 0 or 1 based on if we caused.
 606          * ----------------------------------
 607          *   DECR  |    SAME  | return 0
 608          * ----------------------------------
 609          *   DECR  |    DECR  | return 0
 610          * ----------------------------------
 611          *
 612          * We are a bit fuzz on what an increase or
 613          * decrease is. For BW it is the same if
 614          * it did not change within 1/64th. For
 615          * RTT it stayed the same if it did not
 616          * change within 1/32nd
 617          */
 618         bw_shift = SCTP_BASE_SYSCTL(sctp_rttvar_bw);
 619         rtt = stcb->asoc.my_vtag;
 620         vtag = (rtt << 32) | (((uint32_t)(stcb->sctp_ep->sctp_lport)) << 16) | (stcb->rport);
 621         probepoint = (((uint64_t)net->cwnd) << 32);
 622         rtt = net->rtt;
 623         if (net->cc_mod.rtcc.rtt_set_this_sack) {
 624                 net->cc_mod.rtcc.rtt_set_this_sack = 0;
 625                 bytes_for_this_rtt = net->cc_mod.rtcc.bw_bytes - net->cc_mod.rtcc.bw_bytes_at_last_rttc;
 626                 net->cc_mod.rtcc.bw_bytes_at_last_rttc = net->cc_mod.rtcc.bw_bytes;
 627                 if (net->rtt) {
 628                         div = net->rtt / 1000;
 629                         if (div) {
 630                                 inst_bw = bytes_for_this_rtt / div;
 631                                 inst_off = inst_bw >> bw_shift;
 632                                 if (inst_bw > nbw)
 633                                         inst_ind = SCTP_INST_GAINING;
 634                                 else if ((inst_bw + inst_off) < nbw)
 635                                         inst_ind = SCTP_INST_LOOSING;
 636                                 else
 637                                         inst_ind = SCTP_INST_NEUTRAL;
 638                                 probepoint |= ((0xb << 16) | inst_ind);
 639                         } else {
 640                                 inst_ind = net->cc_mod.rtcc.last_inst_ind;
 641                                 inst_bw = bytes_for_this_rtt / (uint64_t)(net->rtt);
 642                                 /* Can't determine do not change */
 643                                 probepoint |= ((0xc << 16) | inst_ind);
 644                         }
 645                 } else {
 646                         inst_ind = net->cc_mod.rtcc.last_inst_ind;
 647                         inst_bw = bytes_for_this_rtt;
 648                         /* Can't determine do not change */
 649                         probepoint |= ((0xd << 16) | inst_ind);
 650                 }
 651                 SDT_PROBE5(sctp, cwnd, net, rttvar,
 652                     vtag,
 653                     ((nbw << 32) | inst_bw),
 654                     ((net->cc_mod.rtcc.lbw_rtt << 32) | rtt),
 655                     net->flight_size,
 656                     probepoint);
 657         } else {
 658                 /* No rtt measurement, use last one */
 659                 inst_ind = net->cc_mod.rtcc.last_inst_ind;
 660         }
 661         bw_offset = net->cc_mod.rtcc.lbw >> bw_shift;
 662         if (nbw > net->cc_mod.rtcc.lbw + bw_offset) {
 663                 ret = cc_bw_increase(stcb, net, nbw, vtag);
 664                 goto out;
 665         }
 666         rtt_offset = net->cc_mod.rtcc.lbw_rtt >> SCTP_BASE_SYSCTL(sctp_rttvar_rtt);
 667         if (nbw < net->cc_mod.rtcc.lbw - bw_offset) {
 668                 ret = cc_bw_decrease(stcb, net, nbw, rtt_offset, vtag, inst_ind);
 669                 goto out;
 670         }
 671         /*
 672          * If we reach here then we are in a situation where the bw stayed
 673          * the same.
 674          */
 675         ret = cc_bw_same(stcb, net, nbw, rtt_offset, vtag, inst_ind);
 676 out:
 677         net->cc_mod.rtcc.last_inst_ind = inst_ind;
 678         return (ret);
 679 }
 680
 681 static void
 682 sctp_cwnd_update_after_sack_common(struct sctp_tcb *stcb,
 683     struct sctp_association *asoc,
 684     int accum_moved, int reneged_all SCTP_UNUSED, int will_exit, int use_rtcc)
 685 {
 686         struct sctp_nets *net;
 687         int old_cwnd;
 688         uint32_t t_ssthresh, t_cwnd, incr;
 689         uint64_t t_ucwnd_sbw;
 690         uint64_t t_path_mptcp;
 691         uint64_t mptcp_like_alpha;
 692         uint32_t srtt;
 693         uint64_t max_path;
 694
 695         /* MT FIXME: Don't compute this over and over again */
 696         t_ssthresh = 0;
 697         t_cwnd = 0;
 698         t_ucwnd_sbw = 0;
 699         t_path_mptcp = 0;
 700         mptcp_like_alpha = 1;
 701         if ((stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) ||
 702             (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV2) ||
 703             (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_MPTCP)) {
 704                 max_path = 0;
 705                 TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
 706                         t_ssthresh += net->ssthresh;
 707                         t_cwnd += net->cwnd;
 708                         /* lastsa>>3;  we don't need to devide ... */
 709                         srtt = net->lastsa;
 710                         if (srtt > 0) {
 711                                 uint64_t tmp;
 712
 713                                 t_ucwnd_sbw += (uint64_t)net->cwnd / (uint64_t)srtt;
 714                                 t_path_mptcp += (((uint64_t)net->cwnd) << SHIFT_MPTCP_MULTI_Z) /
 715                                     (((uint64_t)net->mtu) * (uint64_t)srtt);
 716                                 tmp = (((uint64_t)net->cwnd) << SHIFT_MPTCP_MULTI_N) /
 717                                     ((uint64_t)net->mtu * (uint64_t)(srtt * srtt));
 718                                 if (tmp > max_path) {
 719                                         max_path = tmp;
 720                                 }
 721                         }
 722                 }
 723                 if (t_path_mptcp > 0) {
 724                         mptcp_like_alpha = max_path / (t_path_mptcp * t_path_mptcp);
 725                 } else {
 726                         mptcp_like_alpha = 1;
 727                 }
 728         }
 729         if (t_ssthresh == 0) {
 730                 t_ssthresh = 1;
 731         }
 732         if (t_ucwnd_sbw == 0) {
 733                 t_ucwnd_sbw = 1;
 734         }
 735         /******************************/
 736         /* update cwnd and Early FR   */
 737         /******************************/
 738         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
 739
 740 #ifdef JANA_CMT_FAST_RECOVERY
 741                 /*
 742                  * CMT fast recovery code. Need to debug.
 743                  */
 744                 if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
 745                         if (SCTP_TSN_GE(asoc->last_acked_seq, net->fast_recovery_tsn) ||
 746                             SCTP_TSN_GE(net->pseudo_cumack, net->fast_recovery_tsn)) {
 747                                 net->will_exit_fast_recovery = 1;
 748                         }
 749                 }
 750 #endif
 751                 /* if nothing was acked on this destination skip it */
 752                 if (net->net_ack == 0) {
 753                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 754                                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
 755                         }
 756                         continue;
 757                 }
 758 #ifdef JANA_CMT_FAST_RECOVERY
 759                 /*
 760                  * CMT fast recovery code
 761                  */
 762                 /*
 763                  * if (sctp_cmt_on_off > 0 && net->fast_retran_loss_recovery
 764                  * && net->will_exit_fast_recovery == 0) { @@@ Do something
 765                  * } else if (sctp_cmt_on_off == 0 &&
 766                  * asoc->fast_retran_loss_recovery && will_exit == 0) {
 767                  */
 768 #endif
 769
 770                 if (asoc->fast_retran_loss_recovery &&
 771                     (will_exit == 0) &&
 772                     (asoc->sctp_cmt_on_off == 0)) {
 773                         /*
 774                          * If we are in loss recovery we skip any cwnd
 775                          * update
 776                          */
 777                         return;
 778                 }
 779                 /*
 780                  * Did any measurements go on for this network?
 781                  */
 782                 if (use_rtcc && (net->cc_mod.rtcc.tls_needs_set > 0)) {
 783                         uint64_t nbw;
 784
 785                         /*
 786                          * At this point our bw_bytes has been updated by
 787                          * incoming sack information.
 788                          *
 789                          * But our bw may not yet be set.
 790                          *
 791                          */
 792                         if ((net->cc_mod.rtcc.new_tot_time / 1000) > 0) {
 793                                 nbw = net->cc_mod.rtcc.bw_bytes / (net->cc_mod.rtcc.new_tot_time / 1000);
 794                         } else {
 795                                 nbw = net->cc_mod.rtcc.bw_bytes;
 796                         }
 797                         if (net->cc_mod.rtcc.lbw) {
 798                                 if (cc_bw_limit(stcb, net, nbw)) {
 799                                         /* Hold here, no update */
 800                                         continue;
 801                                 }
 802                         } else {
 803                                 uint64_t vtag, probepoint;
 804
 805                                 probepoint = (((uint64_t)net->cwnd) << 32);
 806                                 probepoint |= ((0xa << 16) | 0);
 807                                 vtag = (net->rtt << 32) |
 808                                     (((uint32_t)(stcb->sctp_ep->sctp_lport)) << 16) |
 809                                     (stcb->rport);
 810
 811                                 SDT_PROBE5(sctp, cwnd, net, rttvar,
 812                                     vtag,
 813                                     nbw,
 814                                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
 815                                     net->flight_size,
 816                                     probepoint);
 817                                 net->cc_mod.rtcc.lbw = nbw;
 818                                 net->cc_mod.rtcc.lbw_rtt = net->rtt;
 819                                 if (net->cc_mod.rtcc.rtt_set_this_sack) {
 820                                         net->cc_mod.rtcc.rtt_set_this_sack = 0;
 821                                         net->cc_mod.rtcc.bw_bytes_at_last_rttc = net->cc_mod.rtcc.bw_bytes;
 822                                 }
 823                         }
 824                 }
 825                 /*
 826                  * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
 827                  * moved.
 828                  */
 829                 if (accum_moved ||
 830                     ((asoc->sctp_cmt_on_off > 0) && net->new_pseudo_cumack)) {
 831                         /* If the cumulative ack moved we can proceed */
 832                         if (net->cwnd <= net->ssthresh) {
 833                                 /* We are in slow start */
 834                                 if (net->flight_size + net->net_ack >= net->cwnd) {
 835                                         uint32_t limit;
 836
 837                                         old_cwnd = net->cwnd;
 838                                         switch (asoc->sctp_cmt_on_off) {
 839                                         case SCTP_CMT_RPV1:
 840                                                 limit = (uint32_t)(((uint64_t)net->mtu *
 841                                                     (uint64_t)SCTP_BASE_SYSCTL(sctp_L2_abc_variable) *
 842                                                     (uint64_t)net->ssthresh) /
 843                                                     (uint64_t)t_ssthresh);
 844                                                 incr = (uint32_t)(((uint64_t)net->net_ack *
 845                                                     (uint64_t)net->ssthresh) /
 846                                                     (uint64_t)t_ssthresh);
 847                                                 if (incr > limit) {
 848                                                         incr = limit;
 849                                                 }
 850                                                 if (incr == 0) {
 851                                                         incr = 1;
 852                                                 }
 853                                                 break;
 854                                         case SCTP_CMT_RPV2:
 855                                                 /*
 856                                                  * lastsa>>3;  we don't need
 857                                                  * to divide ...
 858                                                  */
 859                                                 srtt = net->lastsa;
 860                                                 if (srtt == 0) {
 861                                                         srtt = 1;
 862                                                 }
 863                                                 limit = (uint32_t)(((uint64_t)net->mtu *
 864                                                     (uint64_t)SCTP_BASE_SYSCTL(sctp_L2_abc_variable) *
 865                                                     (uint64_t)net->cwnd) /
 866                                                     ((uint64_t)srtt * t_ucwnd_sbw));
 867                                                 /* INCREASE FACTOR */
 868                                                 incr = (uint32_t)(((uint64_t)net->net_ack *
 869                                                     (uint64_t)net->cwnd) /
 870                                                     ((uint64_t)srtt * t_ucwnd_sbw));
 871                                                 /* INCREASE FACTOR */
 872                                                 if (incr > limit) {
 873                                                         incr = limit;
 874                                                 }
 875                                                 if (incr == 0) {
 876                                                         incr = 1;
 877                                                 }
 878                                                 break;
 879                                         case SCTP_CMT_MPTCP:
 880                                                 limit = (uint32_t)(((uint64_t)net->mtu *
 881                                                     mptcp_like_alpha *
 882                                                     (uint64_t)SCTP_BASE_SYSCTL(sctp_L2_abc_variable)) >>
 883                                                     SHIFT_MPTCP_MULTI);
 884                                                 incr = (uint32_t)(((uint64_t)net->net_ack *
 885                                                     mptcp_like_alpha) >>
 886                                                     SHIFT_MPTCP_MULTI);
 887                                                 if (incr > limit) {
 888                                                         incr = limit;
 889                                                 }
 890                                                 if (incr > net->net_ack) {
 891                                                         incr = net->net_ack;
 892                                                 }
 893                                                 if (incr > net->mtu) {
 894                                                         incr = net->mtu;
 895                                                 }
 896                                                 break;
 897                                         default:
 898                                                 incr = net->net_ack;
 899                                                 if (incr > net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable)) {
 900                                                         incr = net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable);
 901                                                 }
 902                                                 break;
 903                                         }
 904                                         net->cwnd += incr;
 905                                         sctp_enforce_cwnd_limit(asoc, net);
 906                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 907                                                 sctp_log_cwnd(stcb, net, incr,
 908                                                     SCTP_CWND_LOG_FROM_SS);
 909                                         }
 910                                         SDT_PROBE5(sctp, cwnd, net, ack,
 911                                             stcb->asoc.my_vtag,
 912                                             ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
 913                                             net,
 914                                             old_cwnd, net->cwnd);
 915                                 } else {
 916                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 917                                                 sctp_log_cwnd(stcb, net, net->net_ack,
 918                                                     SCTP_CWND_LOG_NOADV_SS);
 919                                         }
 920                                 }
 921                         } else {
 922                                 /* We are in congestion avoidance */
 923                                 /*
 924                                  * Add to pba
 925                                  */
 926                                 net->partial_bytes_acked += net->net_ack;
 927
 928                                 if ((net->flight_size + net->net_ack >= net->cwnd) &&
 929                                     (net->partial_bytes_acked >= net->cwnd)) {
 930                                         net->partial_bytes_acked -= net->cwnd;
 931                                         old_cwnd = net->cwnd;
 932                                         switch (asoc->sctp_cmt_on_off) {
 933                                         case SCTP_CMT_RPV1:
 934                                                 incr = (uint32_t)(((uint64_t)net->mtu *
 935                                                     (uint64_t)net->ssthresh) /
 936                                                     (uint64_t)t_ssthresh);
 937                                                 if (incr == 0) {
 938                                                         incr = 1;
 939                                                 }
 940                                                 break;
 941                                         case SCTP_CMT_RPV2:
 942                                                 /*
 943                                                  * lastsa>>3;  we don't need
 944                                                  * to divide ...
 945                                                  */
 946                                                 srtt = net->lastsa;
 947                                                 if (srtt == 0) {
 948                                                         srtt = 1;
 949                                                 }
 950                                                 incr = (uint32_t)((uint64_t)net->mtu *
 951                                                     (uint64_t)net->cwnd /
 952                                                     ((uint64_t)srtt *
 953                                                     t_ucwnd_sbw));
 954                                                 /* INCREASE FACTOR */
 955                                                 if (incr == 0) {
 956                                                         incr = 1;
 957                                                 }
 958                                                 break;
 959                                         case SCTP_CMT_MPTCP:
 960                                                 incr = (uint32_t)((mptcp_like_alpha *
 961                                                     (uint64_t)net->cwnd) >>
 962                                                     SHIFT_MPTCP_MULTI);
 963                                                 if (incr > net->mtu) {
 964                                                         incr = net->mtu;
 965                                                 }
 966                                                 break;
 967                                         default:
 968                                                 incr = net->mtu;
 969                                                 break;
 970                                         }
 971                                         net->cwnd += incr;
 972                                         sctp_enforce_cwnd_limit(asoc, net);
 973                                         SDT_PROBE5(sctp, cwnd, net, ack,
 974                                             stcb->asoc.my_vtag,
 975                                             ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
 976                                             net,
 977                                             old_cwnd, net->cwnd);
 978                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
 979                                                 sctp_log_cwnd(stcb, net, net->mtu,
 980                                                     SCTP_CWND_LOG_FROM_CA);
 981                                         }
 982                                 } else {
 983                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 984                                                 sctp_log_cwnd(stcb, net, net->net_ack,
 985                                                     SCTP_CWND_LOG_NOADV_CA);
 986                                         }
 987                                 }
 988                         }
 989                 } else {
 990                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
 991                                 sctp_log_cwnd(stcb, net, net->mtu,
 992                                     SCTP_CWND_LOG_NO_CUMACK);
 993                         }
 994                 }
 995         }
 996 }
 997
 998 static void
 999 sctp_cwnd_update_exit_pf_common(struct sctp_tcb *stcb, struct sctp_nets *net)
1000 {
1001         int old_cwnd;
1002
1003         old_cwnd = net->cwnd;
1004         net->cwnd = net->mtu;
1005         SDT_PROBE5(sctp, cwnd, net, ack,
1006             stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
1007             old_cwnd, net->cwnd);
1008         SCTPDBG(SCTP_DEBUG_INDATA1, "Destination %p moved from PF to reachable with cwnd %d.\n",
1009             (void *)net, net->cwnd);
1010 }
1011
1012
1013 static void
1014 sctp_cwnd_update_after_timeout(struct sctp_tcb *stcb, struct sctp_nets *net)
1015 {
1016         int old_cwnd = net->cwnd;
1017         uint32_t t_ssthresh, t_cwnd;
1018         uint64_t t_ucwnd_sbw;
1019
1020         /* MT FIXME: Don't compute this over and over again */
1021         t_ssthresh = 0;
1022         t_cwnd = 0;
1023         if ((stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) ||
1024             (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV2)) {
1025                 struct sctp_nets *lnet;
1026                 uint32_t srtt;
1027
1028                 t_ucwnd_sbw = 0;
1029                 TAILQ_FOREACH(lnet, &stcb->asoc.nets, sctp_next) {
1030                         t_ssthresh += lnet->ssthresh;
1031                         t_cwnd += lnet->cwnd;
1032                         srtt = lnet->lastsa;
1033                         /* lastsa>>3;  we don't need to divide ... */
1034                         if (srtt > 0) {
1035                                 t_ucwnd_sbw += (uint64_t)lnet->cwnd / (uint64_t)srtt;
1036                         }
1037                 }
1038                 if (t_ssthresh < 1) {
1039                         t_ssthresh = 1;
1040                 }
1041                 if (t_ucwnd_sbw < 1) {
1042                         t_ucwnd_sbw = 1;
1043                 }
1044                 if (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) {
1045                         net->ssthresh = (uint32_t)(((uint64_t)4 *
1046                             (uint64_t)net->mtu *
1047                             (uint64_t)net->ssthresh) /
1048                             (uint64_t)t_ssthresh);
1049                 } else {
1050                         uint64_t cc_delta;
1051
1052                         srtt = net->lastsa;
1053                         /* lastsa>>3;  we don't need to divide ... */
1054                         if (srtt == 0) {
1055                                 srtt = 1;
1056                         }
1057                         cc_delta = t_ucwnd_sbw * (uint64_t)srtt / 2;
1058                         if (cc_delta < t_cwnd) {
1059                                 net->ssthresh = (uint32_t)((uint64_t)t_cwnd - cc_delta);
1060                         } else {
1061                                 net->ssthresh = net->mtu;
1062                         }
1063                 }
1064                 if ((net->cwnd > t_cwnd / 2) &&
1065                     (net->ssthresh < net->cwnd - t_cwnd / 2)) {
1066                         net->ssthresh = net->cwnd - t_cwnd / 2;
1067                 }
1068                 if (net->ssthresh < net->mtu) {
1069                         net->ssthresh = net->mtu;
1070                 }
1071         } else {
1072                 net->ssthresh = max(net->cwnd / 2, 4 * net->mtu);
1073         }
1074         net->cwnd = net->mtu;
1075         net->partial_bytes_acked = 0;
1076         SDT_PROBE5(sctp, cwnd, net, to,
1077             stcb->asoc.my_vtag,
1078             ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
1079             net,
1080             old_cwnd, net->cwnd);
1081         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1082                 sctp_log_cwnd(stcb, net, net->cwnd - old_cwnd, SCTP_CWND_LOG_FROM_RTX);
1083         }
1084 }
1085
1086 static void
1087 sctp_cwnd_update_after_ecn_echo_common(struct sctp_tcb *stcb, struct sctp_nets *net,
1088     int in_window, int num_pkt_lost, int use_rtcc)
1089 {
1090         int old_cwnd = net->cwnd;
1091
1092         if ((use_rtcc) && (net->lan_type == SCTP_LAN_LOCAL) && (net->cc_mod.rtcc.use_dccc_ecn)) {
1093                 /* Data center Congestion Control */
1094                 if (in_window == 0) {
1095                         /*
1096                          * Go to CA with the cwnd at the point we sent the
1097                          * TSN that was marked with a CE.
1098                          */
1099                         if (net->ecn_prev_cwnd < net->cwnd) {
1100                                 /* Restore to prev cwnd */
1101                                 net->cwnd = net->ecn_prev_cwnd - (net->mtu * num_pkt_lost);
1102                         } else {
1103                                 /* Just cut in 1/2 */
1104                                 net->cwnd /= 2;
1105                         }
1106                         /* Drop to CA */
1107                         net->ssthresh = net->cwnd - (num_pkt_lost * net->mtu);
1108                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1109                                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
1110                         }
1111                 } else {
1112                         /*
1113                          * Further tuning down required over the drastic
1114                          * original cut
1115                          */
1116                         net->ssthresh -= (net->mtu * num_pkt_lost);
1117                         net->cwnd -= (net->mtu * num_pkt_lost);
1118                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1119                                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
1120                         }
1121
1122                 }
1123                 SCTP_STAT_INCR(sctps_ecnereducedcwnd);
1124         } else {
1125                 if (in_window == 0) {
1126                         SCTP_STAT_INCR(sctps_ecnereducedcwnd);
1127                         net->ssthresh = net->cwnd / 2;
1128                         if (net->ssthresh < net->mtu) {
1129                                 net->ssthresh = net->mtu;
1130                                 /*
1131                                  * here back off the timer as well, to slow
1132                                  * us down
1133                                  */
1134                                 net->RTO <<= 1;
1135                         }
1136                         net->cwnd = net->ssthresh;
1137                         SDT_PROBE5(sctp, cwnd, net, ecn,
1138                             stcb->asoc.my_vtag,
1139                             ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
1140                             net,
1141                             old_cwnd, net->cwnd);
1142                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1143                                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
1144                         }
1145                 }
1146         }
1147
1148 }
1149
1150 static void
1151 sctp_cwnd_update_after_packet_dropped(struct sctp_tcb *stcb,
1152     struct sctp_nets *net, struct sctp_pktdrop_chunk *cp,
1153     uint32_t *bottle_bw, uint32_t *on_queue)
1154 {
1155         uint32_t bw_avail;
1156         unsigned int incr;
1157         int old_cwnd = net->cwnd;
1158
1159         /* get bottle neck bw */
1160         *bottle_bw = ntohl(cp->bottle_bw);
1161         /* and whats on queue */
1162         *on_queue = ntohl(cp->current_onq);
1163         /*
1164          * adjust the on-queue if our flight is more it could be that the
1165          * router has not yet gotten data "in-flight" to it
1166          */
1167         if (*on_queue < net->flight_size) {
1168                 *on_queue = net->flight_size;
1169         }
1170         /* rtt is measured in micro seconds, bottle_bw in bytes per second */
1171         bw_avail = (uint32_t)(((uint64_t)(*bottle_bw) * net->rtt) / (uint64_t)1000000);
1172         if (bw_avail > *bottle_bw) {
1173                 /*
1174                  * Cap the growth to no more than the bottle neck. This can
1175                  * happen as RTT slides up due to queues. It also means if
1176                  * you have more than a 1 second RTT with a empty queue you
1177                  * will be limited to the bottle_bw per second no matter if
1178                  * other points have 1/2 the RTT and you could get more
1179                  * out...
1180                  */
1181                 bw_avail = *bottle_bw;
1182         }
1183         if (*on_queue > bw_avail) {
1184                 /*
1185                  * No room for anything else don't allow anything else to be
1186                  * "added to the fire".
1187                  */
1188                 int seg_inflight, seg_onqueue, my_portion;
1189
1190                 net->partial_bytes_acked = 0;
1191                 /* how much are we over queue size? */
1192                 incr = *on_queue - bw_avail;
1193                 if (stcb->asoc.seen_a_sack_this_pkt) {
1194                         /*
1195                          * undo any cwnd adjustment that the sack might have
1196                          * made
1197                          */
1198                         net->cwnd = net->prev_cwnd;
1199                 }
1200                 /* Now how much of that is mine? */
1201                 seg_inflight = net->flight_size / net->mtu;
1202                 seg_onqueue = *on_queue / net->mtu;
1203                 my_portion = (incr * seg_inflight) / seg_onqueue;
1204
1205                 /* Have I made an adjustment already */
1206                 if (net->cwnd > net->flight_size) {
1207                         /*
1208                          * for this flight I made an adjustment we need to
1209                          * decrease the portion by a share our previous
1210                          * adjustment.
1211                          */
1212                         int diff_adj;
1213
1214                         diff_adj = net->cwnd - net->flight_size;
1215                         if (diff_adj > my_portion)
1216                                 my_portion = 0;
1217                         else
1218                                 my_portion -= diff_adj;
1219                 }
1220                 /*
1221                  * back down to the previous cwnd (assume we have had a sack
1222                  * before this packet). minus what ever portion of the
1223                  * overage is my fault.
1224                  */
1225                 net->cwnd -= my_portion;
1226
1227                 /* we will NOT back down more than 1 MTU */
1228                 if (net->cwnd <= net->mtu) {
1229                         net->cwnd = net->mtu;
1230                 }
1231                 /* force into CA */
1232                 net->ssthresh = net->cwnd - 1;
1233         } else {
1234                 /*
1235                  * Take 1/4 of the space left or max burst up .. whichever
1236                  * is less.
1237                  */
1238                 incr = (bw_avail - *on_queue) >> 2;
1239                 if ((stcb->asoc.max_burst > 0) &&
1240                     (stcb->asoc.max_burst * net->mtu < incr)) {
1241                         incr = stcb->asoc.max_burst * net->mtu;
1242                 }
1243                 net->cwnd += incr;
1244         }
1245         if (net->cwnd > bw_avail) {
1246                 /* We can't exceed the pipe size */
1247                 net->cwnd = bw_avail;
1248         }
1249         if (net->cwnd < net->mtu) {
1250                 /* We always have 1 MTU */
1251                 net->cwnd = net->mtu;
1252         }
1253         sctp_enforce_cwnd_limit(&stcb->asoc, net);
1254         if (net->cwnd - old_cwnd != 0) {
1255                 /* log only changes */
1256                 SDT_PROBE5(sctp, cwnd, net, pd,
1257                     stcb->asoc.my_vtag,
1258                     ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
1259                     net,
1260                     old_cwnd, net->cwnd);
1261                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1262                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
1263                             SCTP_CWND_LOG_FROM_SAT);
1264                 }
1265         }
1266 }
1267
1268 static void
1269 sctp_cwnd_update_after_output(struct sctp_tcb *stcb,
1270     struct sctp_nets *net, int burst_limit)
1271 {
1272         int old_cwnd = net->cwnd;
1273
1274         if (net->ssthresh < net->cwnd)
1275                 net->ssthresh = net->cwnd;
1276         if (burst_limit) {
1277                 net->cwnd = (net->flight_size + (burst_limit * net->mtu));
1278                 sctp_enforce_cwnd_limit(&stcb->asoc, net);
1279                 SDT_PROBE5(sctp, cwnd, net, bl,
1280                     stcb->asoc.my_vtag,
1281                     ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
1282                     net,
1283                     old_cwnd, net->cwnd);
1284                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1285                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_BRST);
1286                 }
1287         }
1288 }
1289
1290 static void
1291 sctp_cwnd_update_after_sack(struct sctp_tcb *stcb,
1292     struct sctp_association *asoc,
1293     int accum_moved, int reneged_all, int will_exit)
1294 {
1295         /* Passing a zero argument in last disables the rtcc algorithm */
1296         sctp_cwnd_update_after_sack_common(stcb, asoc, accum_moved, reneged_all, will_exit, 0);
1297 }
1298
1299 static void
1300 sctp_cwnd_update_after_ecn_echo(struct sctp_tcb *stcb, struct sctp_nets *net,
1301     int in_window, int num_pkt_lost)
1302 {
1303         /* Passing a zero argument in last disables the rtcc algorithm */
1304         sctp_cwnd_update_after_ecn_echo_common(stcb, net, in_window, num_pkt_lost, 0);
1305 }
1306
1307 /* Here starts the RTCCVAR type CC invented by RRS which
1308  * is a slight mod to RFC2581. We reuse a common routine or
1309  * two since these algorithms are so close and need to
1310  * remain the same.
1311  */
1312 static void
1313 sctp_cwnd_update_rtcc_after_ecn_echo(struct sctp_tcb *stcb, struct sctp_nets *net,
1314     int in_window, int num_pkt_lost)
1315 {
1316         sctp_cwnd_update_after_ecn_echo_common(stcb, net, in_window, num_pkt_lost, 1);
1317 }
1318
1319
1320 static
1321 void
1322 sctp_cwnd_update_rtcc_tsn_acknowledged(struct sctp_nets *net,
1323     struct sctp_tmit_chunk *tp1)
1324 {
1325         net->cc_mod.rtcc.bw_bytes += tp1->send_size;
1326 }
1327
1328 static void
1329 sctp_cwnd_prepare_rtcc_net_for_sack(struct sctp_tcb *stcb SCTP_UNUSED,
1330     struct sctp_nets *net)
1331 {
1332         if (net->cc_mod.rtcc.tls_needs_set > 0) {
1333                 /* We had a bw measurment going on */
1334                 struct timeval ltls;
1335
1336                 SCTP_GETPTIME_TIMEVAL(&ltls);
1337                 timevalsub(&ltls, &net->cc_mod.rtcc.tls);
1338                 net->cc_mod.rtcc.new_tot_time = (ltls.tv_sec * 1000000) + ltls.tv_usec;
1339         }
1340 }
1341
1342 static void
1343 sctp_cwnd_new_rtcc_transmission_begins(struct sctp_tcb *stcb,
1344     struct sctp_nets *net)
1345 {
1346         uint64_t vtag, probepoint;
1347
1348         if (net->cc_mod.rtcc.lbw) {
1349                 /* Clear the old bw.. we went to 0 in-flight */
1350                 vtag = (net->rtt << 32) | (((uint32_t)(stcb->sctp_ep->sctp_lport)) << 16) |
1351                     (stcb->rport);
1352                 probepoint = (((uint64_t)net->cwnd) << 32);
1353                 /* Probe point 8 */
1354                 probepoint |= ((8 << 16) | 0);
1355                 SDT_PROBE5(sctp, cwnd, net, rttvar,
1356                     vtag,
1357                     ((net->cc_mod.rtcc.lbw << 32) | 0),
1358                     ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
1359                     net->flight_size,
1360                     probepoint);
1361                 net->cc_mod.rtcc.lbw_rtt = 0;
1362                 net->cc_mod.rtcc.cwnd_at_bw_set = 0;
1363                 net->cc_mod.rtcc.lbw = 0;
1364                 net->cc_mod.rtcc.bw_bytes_at_last_rttc = 0;
1365                 net->cc_mod.rtcc.vol_reduce = 0;
1366                 net->cc_mod.rtcc.bw_tot_time = 0;
1367                 net->cc_mod.rtcc.bw_bytes = 0;
1368                 net->cc_mod.rtcc.tls_needs_set = 0;
1369                 if (net->cc_mod.rtcc.steady_step) {
1370                         net->cc_mod.rtcc.vol_reduce = 0;
1371                         net->cc_mod.rtcc.step_cnt = 0;
1372                         net->cc_mod.rtcc.last_step_state = 0;
1373                 }
1374                 if (net->cc_mod.rtcc.ret_from_eq) {
1375                         /* less aggressive one - reset cwnd too */
1376                         uint32_t cwnd_in_mtu, cwnd;
1377
1378                         cwnd_in_mtu = SCTP_BASE_SYSCTL(sctp_initial_cwnd);
1379                         if (cwnd_in_mtu == 0) {
1380                                 /*
1381                                  * Using 0 means that the value of RFC 4960
1382                                  * is used.
1383                                  */
1384                                 cwnd = min((net->mtu * 4), max((2 * net->mtu), SCTP_INITIAL_CWND));
1385                         } else {
1386                                 /*
1387                                  * We take the minimum of the burst limit
1388                                  * and the initial congestion window.
1389                                  */
1390                                 if ((stcb->asoc.max_burst > 0) && (cwnd_in_mtu > stcb->asoc.max_burst))
1391                                         cwnd_in_mtu = stcb->asoc.max_burst;
1392                                 cwnd = (net->mtu - sizeof(struct sctphdr)) * cwnd_in_mtu;
1393                         }
1394                         if (net->cwnd > cwnd) {
1395                                 /*
1396                                  * Only set if we are not a timeout (i.e.
1397                                  * down to 1 mtu)
1398                                  */
1399                                 net->cwnd = cwnd;
1400                         }
1401                 }
1402         }
1403 }
1404
1405 static void
1406 sctp_set_rtcc_initial_cc_param(struct sctp_tcb *stcb,
1407     struct sctp_nets *net)
1408 {
1409         uint64_t vtag, probepoint;
1410
1411         sctp_set_initial_cc_param(stcb, net);
1412         stcb->asoc.use_precise_time = 1;
1413         probepoint = (((uint64_t)net->cwnd) << 32);
1414         probepoint |= ((9 << 16) | 0);
1415         vtag = (net->rtt << 32) |
1416             (((uint32_t)(stcb->sctp_ep->sctp_lport)) << 16) |
1417             (stcb->rport);
1418         SDT_PROBE5(sctp, cwnd, net, rttvar,
1419             vtag,
1420             0,
1421             0,
1422             0,
1423             probepoint);
1424         net->cc_mod.rtcc.lbw_rtt = 0;
1425         net->cc_mod.rtcc.cwnd_at_bw_set = 0;
1426         net->cc_mod.rtcc.vol_reduce = 0;
1427         net->cc_mod.rtcc.lbw = 0;
1428         net->cc_mod.rtcc.vol_reduce = 0;
1429         net->cc_mod.rtcc.bw_bytes_at_last_rttc = 0;
1430         net->cc_mod.rtcc.bw_tot_time = 0;
1431         net->cc_mod.rtcc.bw_bytes = 0;
1432         net->cc_mod.rtcc.tls_needs_set = 0;
1433         net->cc_mod.rtcc.ret_from_eq = SCTP_BASE_SYSCTL(sctp_rttvar_eqret);
1434         net->cc_mod.rtcc.steady_step = SCTP_BASE_SYSCTL(sctp_steady_step);
1435         net->cc_mod.rtcc.use_dccc_ecn = SCTP_BASE_SYSCTL(sctp_use_dccc_ecn);
1436         net->cc_mod.rtcc.step_cnt = 0;
1437         net->cc_mod.rtcc.last_step_state = 0;
1438
1439
1440 }
1441
1442 static int
1443 sctp_cwnd_rtcc_socket_option(struct sctp_tcb *stcb, int setorget,
1444     struct sctp_cc_option *cc_opt)
1445 {
1446         struct sctp_nets *net;
1447
1448         if (setorget == 1) {
1449                 /* a set */
1450                 if (cc_opt->option == SCTP_CC_OPT_RTCC_SETMODE) {
1451                         if ((cc_opt->aid_value.assoc_value != 0) &&
1452                             (cc_opt->aid_value.assoc_value != 1)) {
1453                                 return (EINVAL);
1454                         }
1455                         TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
1456                                 net->cc_mod.rtcc.ret_from_eq = cc_opt->aid_value.assoc_value;
1457                         }
1458                 } else if (cc_opt->option == SCTP_CC_OPT_USE_DCCC_ECN) {
1459                         if ((cc_opt->aid_value.assoc_value != 0) &&
1460                             (cc_opt->aid_value.assoc_value != 1)) {
1461                                 return (EINVAL);
1462                         }
1463                         TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
1464                                 net->cc_mod.rtcc.use_dccc_ecn = cc_opt->aid_value.assoc_value;
1465                         }
1466                 } else if (cc_opt->option == SCTP_CC_OPT_STEADY_STEP) {
1467                         TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
1468                                 net->cc_mod.rtcc.steady_step = cc_opt->aid_value.assoc_value;
1469                         }
1470                 } else {
1471                         return (EINVAL);
1472                 }
1473         } else {
1474                 /* a get */
1475                 if (cc_opt->option == SCTP_CC_OPT_RTCC_SETMODE) {
1476                         net = TAILQ_FIRST(&stcb->asoc.nets);
1477                         if (net == NULL) {
1478                                 return (EFAULT);
1479                         }
1480                         cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.ret_from_eq;
1481                 } else if (cc_opt->option == SCTP_CC_OPT_USE_DCCC_ECN) {
1482                         net = TAILQ_FIRST(&stcb->asoc.nets);
1483                         if (net == NULL) {
1484                                 return (EFAULT);
1485                         }
1486                         cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.use_dccc_ecn;
1487                 } else if (cc_opt->option == SCTP_CC_OPT_STEADY_STEP) {
1488                         net = TAILQ_FIRST(&stcb->asoc.nets);
1489                         if (net == NULL) {
1490                                 return (EFAULT);
1491                         }
1492                         cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.steady_step;
1493                 } else {
1494                         return (EINVAL);
1495                 }
1496         }
1497         return (0);
1498 }
1499
1500 static void
1501 sctp_cwnd_update_rtcc_packet_transmitted(struct sctp_tcb *stcb SCTP_UNUSED,
1502     struct sctp_nets *net)
1503 {
1504         if (net->cc_mod.rtcc.tls_needs_set == 0) {
1505                 SCTP_GETPTIME_TIMEVAL(&net->cc_mod.rtcc.tls);
1506                 net->cc_mod.rtcc.tls_needs_set = 2;
1507         }
1508 }
1509
1510 static void
1511 sctp_cwnd_update_rtcc_after_sack(struct sctp_tcb *stcb,
1512     struct sctp_association *asoc,
1513     int accum_moved, int reneged_all, int will_exit)
1514 {
1515         /* Passing a one argument at the last enables the rtcc algorithm */
1516         sctp_cwnd_update_after_sack_common(stcb, asoc, accum_moved, reneged_all, will_exit, 1);
1517 }
1518
1519 static void
1520 sctp_rtt_rtcc_calculated(struct sctp_tcb *stcb SCTP_UNUSED,
1521     struct sctp_nets *net,
1522     struct timeval *now SCTP_UNUSED)
1523 {
1524         net->cc_mod.rtcc.rtt_set_this_sack = 1;
1525 }
1526
1527 /* Here starts Sally Floyds HS-TCP */
1528
1529 struct sctp_hs_raise_drop {
1530         int32_t cwnd;
1531         int8_t increase;
1532         int8_t drop_percent;
1533 };
1534
1535 #define SCTP_HS_TABLE_SIZE 73
1536
1537 static const struct sctp_hs_raise_drop sctp_cwnd_adjust[SCTP_HS_TABLE_SIZE] = {
1538         {38, 1, 50},            /* 0   */
1539         {118, 2, 44},           /* 1   */
1540         {221, 3, 41},           /* 2   */
1541         {347, 4, 38},           /* 3   */
1542         {495, 5, 37},           /* 4   */
1543         {663, 6, 35},           /* 5   */
1544         {851, 7, 34},           /* 6   */
1545         {1058, 8, 33},          /* 7   */
1546         {1284, 9, 32},          /* 8   */
1547         {1529, 10, 31},         /* 9   */
1548         {1793, 11, 30},         /* 10  */
1549         {2076, 12, 29},         /* 11  */
1550         {2378, 13, 28},         /* 12  */
1551         {2699, 14, 28},         /* 13  */
1552         {3039, 15, 27},         /* 14  */
1553         {3399, 16, 27},         /* 15  */
1554         {3778, 17, 26},         /* 16  */
1555         {4177, 18, 26},         /* 17  */
1556         {4596, 19, 25},         /* 18  */
1557         {5036, 20, 25},         /* 19  */
1558         {5497, 21, 24},         /* 20  */
1559         {5979, 22, 24},         /* 21  */
1560         {6483, 23, 23},         /* 22  */
1561         {7009, 24, 23},         /* 23  */
1562         {7558, 25, 22},         /* 24  */
1563         {8130, 26, 22},         /* 25  */
1564         {8726, 27, 22},         /* 26  */
1565         {9346, 28, 21},         /* 27  */
1566         {9991, 29, 21},         /* 28  */
1567         {10661, 30, 21},        /* 29  */
1568         {11358, 31, 20},        /* 30  */
1569         {12082, 32, 20},        /* 31  */
1570         {12834, 33, 20},        /* 32  */
1571         {13614, 34, 19},        /* 33  */
1572         {14424, 35, 19},        /* 34  */
1573         {15265, 36, 19},        /* 35  */
1574         {16137, 37, 19},        /* 36  */
1575         {17042, 38, 18},        /* 37  */
1576         {17981, 39, 18},        /* 38  */
1577         {18955, 40, 18},        /* 39  */
1578         {19965, 41, 17},        /* 40  */
1579         {21013, 42, 17},        /* 41  */
1580         {22101, 43, 17},        /* 42  */
1581         {23230, 44, 17},        /* 43  */
1582         {24402, 45, 16},        /* 44  */
1583         {25618, 46, 16},        /* 45  */
1584         {26881, 47, 16},        /* 46  */
1585         {28193, 48, 16},        /* 47  */
1586         {29557, 49, 15},        /* 48  */
1587         {30975, 50, 15},        /* 49  */
1588         {32450, 51, 15},        /* 50  */
1589         {33986, 52, 15},        /* 51  */
1590         {35586, 53, 14},        /* 52  */
1591         {37253, 54, 14},        /* 53  */
1592         {38992, 55, 14},        /* 54  */
1593         {40808, 56, 14},        /* 55  */
1594         {42707, 57, 13},        /* 56  */
1595         {44694, 58, 13},        /* 57  */
1596         {46776, 59, 13},        /* 58  */
1597         {48961, 60, 13},        /* 59  */
1598         {51258, 61, 13},        /* 60  */
1599         {53677, 62, 12},        /* 61  */
1600         {56230, 63, 12},        /* 62  */
1601         {58932, 64, 12},        /* 63  */
1602         {61799, 65, 12},        /* 64  */
1603         {64851, 66, 11},        /* 65  */
1604         {68113, 67, 11},        /* 66  */
1605         {71617, 68, 11},        /* 67  */
1606         {75401, 69, 10},        /* 68  */
1607         {79517, 70, 10},        /* 69  */
1608         {84035, 71, 10},        /* 70  */
1609         {89053, 72, 10},        /* 71  */
1610         {94717, 73, 9}          /* 72  */
1611 };
1612
1613 static void
1614 sctp_hs_cwnd_increase(struct sctp_tcb *stcb, struct sctp_nets *net)
1615 {
1616         int cur_val, i, indx, incr;
1617         int old_cwnd = net->cwnd;
1618
1619         cur_val = net->cwnd >> 10;
1620         indx = SCTP_HS_TABLE_SIZE - 1;
1621
1622         if (cur_val < sctp_cwnd_adjust[0].cwnd) {
1623                 /* normal mode */
1624                 if (net->net_ack > net->mtu) {
1625                         net->cwnd += net->mtu;
1626                 } else {
1627                         net->cwnd += net->net_ack;
1628                 }
1629         } else {
1630                 for (i = net->last_hs_used; i < SCTP_HS_TABLE_SIZE; i++) {
1631                         if (cur_val < sctp_cwnd_adjust[i].cwnd) {
1632                                 indx = i;
1633                                 break;
1634                         }
1635                 }
1636                 net->last_hs_used = indx;
1637                 incr = (((int32_t)sctp_cwnd_adjust[indx].increase) << 10);
1638                 net->cwnd += incr;
1639         }
1640         sctp_enforce_cwnd_limit(&stcb->asoc, net);
1641         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1642                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SS);
1643         }
1644 }
1645
1646 static void
1647 sctp_hs_cwnd_decrease(struct sctp_tcb *stcb, struct sctp_nets *net)
1648 {
1649         int cur_val, i, indx;
1650         int old_cwnd = net->cwnd;
1651
1652         cur_val = net->cwnd >> 10;
1653         if (cur_val < sctp_cwnd_adjust[0].cwnd) {
1654                 /* normal mode */
1655                 net->ssthresh = net->cwnd / 2;
1656                 if (net->ssthresh < (net->mtu * 2)) {
1657                         net->ssthresh = 2 * net->mtu;
1658                 }
1659                 net->cwnd = net->ssthresh;
1660         } else {
1661                 /* drop by the proper amount */
1662                 net->ssthresh = net->cwnd - (int)((net->cwnd / 100) *
1663                     (int32_t)sctp_cwnd_adjust[net->last_hs_used].drop_percent);
1664                 net->cwnd = net->ssthresh;
1665                 /* now where are we */
1666                 indx = net->last_hs_used;
1667                 cur_val = net->cwnd >> 10;
1668                 /* reset where we are in the table */
1669                 if (cur_val < sctp_cwnd_adjust[0].cwnd) {
1670                         /* feel out of hs */
1671                         net->last_hs_used = 0;
1672                 } else {
1673                         for (i = indx; i >= 1; i--) {
1674                                 if (cur_val > sctp_cwnd_adjust[i - 1].cwnd) {
1675                                         break;
1676                                 }
1677                         }
1678                         net->last_hs_used = indx;
1679                 }
1680         }
1681         sctp_enforce_cwnd_limit(&stcb->asoc, net);
1682         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1683                 sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_FR);
1684         }
1685 }
1686
1687 static void
1688 sctp_hs_cwnd_update_after_fr(struct sctp_tcb *stcb,
1689     struct sctp_association *asoc)
1690 {
1691         struct sctp_nets *net;
1692
1693         /*
1694          * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off > 0) &&
1695          * (net->fast_retran_loss_recovery == 0)))
1696          */
1697         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
1698                 if ((asoc->fast_retran_loss_recovery == 0) ||
1699                     (asoc->sctp_cmt_on_off > 0)) {
1700                         /* out of a RFC2582 Fast recovery window? */
1701                         if (net->net_ack > 0) {
1702                                 /*
1703                                  * per section 7.2.3, are there any
1704                                  * destinations that had a fast retransmit
1705                                  * to them. If so what we need to do is
1706                                  * adjust ssthresh and cwnd.
1707                                  */
1708                                 struct sctp_tmit_chunk *lchk;
1709
1710                                 sctp_hs_cwnd_decrease(stcb, net);
1711
1712                                 lchk = TAILQ_FIRST(&asoc->send_queue);
1713
1714                                 net->partial_bytes_acked = 0;
1715                                 /* Turn on fast recovery window */
1716                                 asoc->fast_retran_loss_recovery = 1;
1717                                 if (lchk == NULL) {
1718                                         /* Mark end of the window */
1719                                         asoc->fast_recovery_tsn = asoc->sending_seq - 1;
1720                                 } else {
1721                                         asoc->fast_recovery_tsn = lchk->rec.data.tsn - 1;
1722                                 }
1723
1724                                 /*
1725                                  * CMT fast recovery -- per destination
1726                                  * recovery variable.
1727                                  */
1728                                 net->fast_retran_loss_recovery = 1;
1729
1730                                 if (lchk == NULL) {
1731                                         /* Mark end of the window */
1732                                         net->fast_recovery_tsn = asoc->sending_seq - 1;
1733                                 } else {
1734                                         net->fast_recovery_tsn = lchk->rec.data.tsn - 1;
1735                                 }
1736
1737                                 sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
1738                                     stcb->sctp_ep, stcb, net,
1739                                     SCTP_FROM_SCTP_CC_FUNCTIONS + SCTP_LOC_2);
1740                                 sctp_timer_start(SCTP_TIMER_TYPE_SEND,
1741                                     stcb->sctp_ep, stcb, net);
1742                         }
1743                 } else if (net->net_ack > 0) {
1744                         /*
1745                          * Mark a peg that we WOULD have done a cwnd
1746                          * reduction but RFC2582 prevented this action.
1747                          */
1748                         SCTP_STAT_INCR(sctps_fastretransinrtt);
1749                 }
1750         }
1751 }
1752
1753 static void
1754 sctp_hs_cwnd_update_after_sack(struct sctp_tcb *stcb,
1755     struct sctp_association *asoc,
1756     int accum_moved, int reneged_all SCTP_UNUSED, int will_exit)
1757 {
1758         struct sctp_nets *net;
1759
1760         /******************************/
1761         /* update cwnd and Early FR   */
1762         /******************************/
1763         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
1764
1765 #ifdef JANA_CMT_FAST_RECOVERY
1766                 /*
1767                  * CMT fast recovery code. Need to debug.
1768                  */
1769                 if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
1770                         if (SCTP_TSN_GE(asoc->last_acked_seq, net->fast_recovery_tsn) ||
1771                             SCTP_TSN_GE(net->pseudo_cumack, net->fast_recovery_tsn)) {
1772                                 net->will_exit_fast_recovery = 1;
1773                         }
1774                 }
1775 #endif
1776                 /* if nothing was acked on this destination skip it */
1777                 if (net->net_ack == 0) {
1778                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1779                                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
1780                         }
1781                         continue;
1782                 }
1783 #ifdef JANA_CMT_FAST_RECOVERY
1784                 /*
1785                  * CMT fast recovery code
1786                  */
1787                 /*
1788                  * if (sctp_cmt_on_off > 0 && net->fast_retran_loss_recovery
1789                  * && net->will_exit_fast_recovery == 0) { @@@ Do something
1790                  * } else if (sctp_cmt_on_off == 0 &&
1791                  * asoc->fast_retran_loss_recovery && will_exit == 0) {
1792                  */
1793 #endif
1794
1795                 if (asoc->fast_retran_loss_recovery &&
1796                     (will_exit == 0) &&
1797                     (asoc->sctp_cmt_on_off == 0)) {
1798                         /*
1799                          * If we are in loss recovery we skip any cwnd
1800                          * update
1801                          */
1802                         return;
1803                 }
1804                 /*
1805                  * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
1806                  * moved.
1807                  */
1808                 if (accum_moved ||
1809                     ((asoc->sctp_cmt_on_off > 0) && net->new_pseudo_cumack)) {
1810                         /* If the cumulative ack moved we can proceed */
1811                         if (net->cwnd <= net->ssthresh) {
1812                                 /* We are in slow start */
1813                                 if (net->flight_size + net->net_ack >= net->cwnd) {
1814                                         sctp_hs_cwnd_increase(stcb, net);
1815                                 } else {
1816                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1817                                                 sctp_log_cwnd(stcb, net, net->net_ack,
1818                                                     SCTP_CWND_LOG_NOADV_SS);
1819                                         }
1820                                 }
1821                         } else {
1822                                 /* We are in congestion avoidance */
1823                                 net->partial_bytes_acked += net->net_ack;
1824                                 if ((net->flight_size + net->net_ack >= net->cwnd) &&
1825                                     (net->partial_bytes_acked >= net->cwnd)) {
1826                                         net->partial_bytes_acked -= net->cwnd;
1827                                         net->cwnd += net->mtu;
1828                                         sctp_enforce_cwnd_limit(asoc, net);
1829                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
1830                                                 sctp_log_cwnd(stcb, net, net->mtu,
1831                                                     SCTP_CWND_LOG_FROM_CA);
1832                                         }
1833                                 } else {
1834                                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1835                                                 sctp_log_cwnd(stcb, net, net->net_ack,
1836                                                     SCTP_CWND_LOG_NOADV_CA);
1837                                         }
1838                                 }
1839                         }
1840                 } else {
1841                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
1842                                 sctp_log_cwnd(stcb, net, net->mtu,
1843                                     SCTP_CWND_LOG_NO_CUMACK);
1844                         }
1845                 }
1846         }
1847 }
1848
1849
1850 /*
1851  * H-TCP congestion control. The algorithm is detailed in:
1852  * R.N.Shorten, D.J.Leith:
1853  *   "H-TCP: TCP for high-speed and long-distance networks"
1854  *   Proc. PFLDnet, Argonne, 2004.
1855  * http://www.hamilton.ie/net/htcp3.pdf
1856  */
1857
1858
1859 static int use_rtt_scaling = 1;
1860 static int use_bandwidth_switch = 1;
1861
1862 static inline int
1863 between(uint32_t seq1, uint32_t seq2, uint32_t seq3)
1864 {
1865         return (seq3 - seq2 >= seq1 - seq2);
1866 }
1867
1868 static inline uint32_t
1869 htcp_cong_time(struct htcp *ca)
1870 {
1871         return (sctp_get_tick_count() - ca->last_cong);
1872 }
1873
1874 static inline uint32_t
1875 htcp_ccount(struct htcp *ca)
1876 {
1877         return (htcp_cong_time(ca) / ca->minRTT);
1878 }
1879
1880 static inline void
1881 htcp_reset(struct htcp *ca)
1882 {
1883         ca->undo_last_cong = ca->last_cong;
1884         ca->undo_maxRTT = ca->maxRTT;
1885         ca->undo_old_maxB = ca->old_maxB;
1886         ca->last_cong = sctp_get_tick_count();
1887 }
1888
1889 #ifdef SCTP_NOT_USED
1890
1891 static uint32_t
1892 htcp_cwnd_undo(struct sctp_tcb *stcb, struct sctp_nets *net)
1893 {
1894         net->cc_mod.htcp_ca.last_cong = net->cc_mod.htcp_ca.undo_last_cong;
1895         net->cc_mod.htcp_ca.maxRTT = net->cc_mod.htcp_ca.undo_maxRTT;
1896         net->cc_mod.htcp_ca.old_maxB = net->cc_mod.htcp_ca.undo_old_maxB;
1897         return (max(net->cwnd, ((net->ssthresh / net->mtu << 7) / net->cc_mod.htcp_ca.beta) * net->mtu));
1898 }
1899
1900 #endif
1901
1902 static inline void
1903 measure_rtt(struct sctp_nets *net)
1904 {
1905         uint32_t srtt = net->lastsa >> SCTP_RTT_SHIFT;
1906
1907         /* keep track of minimum RTT seen so far, minRTT is zero at first */
1908         if (net->cc_mod.htcp_ca.minRTT > srtt || !net->cc_mod.htcp_ca.minRTT)
1909                 net->cc_mod.htcp_ca.minRTT = srtt;
1910
1911         /* max RTT */
1912         if (net->fast_retran_ip == 0 && net->ssthresh < 0xFFFF && htcp_ccount(&net->cc_mod.htcp_ca) > 3) {
1913                 if (net->cc_mod.htcp_ca.maxRTT < net->cc_mod.htcp_ca.minRTT)
1914                         net->cc_mod.htcp_ca.maxRTT = net->cc_mod.htcp_ca.minRTT;
1915                 if (net->cc_mod.htcp_ca.maxRTT < srtt && srtt <= net->cc_mod.htcp_ca.maxRTT + MSEC_TO_TICKS(20))
1916                         net->cc_mod.htcp_ca.maxRTT = srtt;
1917         }
1918 }
1919
1920 static void
1921 measure_achieved_throughput(struct sctp_nets *net)
1922 {
1923         uint32_t now = sctp_get_tick_count();
1924
1925         if (net->fast_retran_ip == 0)
1926                 net->cc_mod.htcp_ca.bytes_acked = net->net_ack;
1927
1928         if (!use_bandwidth_switch)
1929                 return;
1930
1931         /* achieved throughput calculations */
1932         /* JRS - not 100% sure of this statement */
1933         if (net->fast_retran_ip == 1) {
1934                 net->cc_mod.htcp_ca.bytecount = 0;
1935                 net->cc_mod.htcp_ca.lasttime = now;
1936                 return;
1937         }
1938
1939         net->cc_mod.htcp_ca.bytecount += net->net_ack;
1940         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)) &&
1941             (now - net->cc_mod.htcp_ca.lasttime >= net->cc_mod.htcp_ca.minRTT) &&
1942             (net->cc_mod.htcp_ca.minRTT > 0)) {
1943                 uint32_t cur_Bi = net->cc_mod.htcp_ca.bytecount / net->mtu * hz / (now - net->cc_mod.htcp_ca.lasttime);
1944
1945                 if (htcp_ccount(&net->cc_mod.htcp_ca) <= 3) {
1946                         /* just after backoff */
1947                         net->cc_mod.htcp_ca.minB = net->cc_mod.htcp_ca.maxB = net->cc_mod.htcp_ca.Bi = cur_Bi;
1948                 } else {
1949                         net->cc_mod.htcp_ca.Bi = (3 * net->cc_mod.htcp_ca.Bi + cur_Bi) / 4;
1950                         if (net->cc_mod.htcp_ca.Bi > net->cc_mod.htcp_ca.maxB)
1951                                 net->cc_mod.htcp_ca.maxB = net->cc_mod.htcp_ca.Bi;
1952                         if (net->cc_mod.htcp_ca.minB > net->cc_mod.htcp_ca.maxB)
1953                                 net->cc_mod.htcp_ca.minB = net->cc_mod.htcp_ca.maxB;
1954                 }
1955                 net->cc_mod.htcp_ca.bytecount = 0;
1956                 net->cc_mod.htcp_ca.lasttime = now;
1957         }
1958 }
1959
1960 static inline void
1961 htcp_beta_update(struct htcp *ca, uint32_t minRTT, uint32_t maxRTT)
1962 {
1963         if (use_bandwidth_switch) {
1964                 uint32_t maxB = ca->maxB;
1965                 uint32_t old_maxB = ca->old_maxB;
1966
1967                 ca->old_maxB = ca->maxB;
1968
1969                 if (!between(5 * maxB, 4 * old_maxB, 6 * old_maxB)) {
1970                         ca->beta = BETA_MIN;
1971                         ca->modeswitch = 0;
1972                         return;
1973                 }
1974         }
1975
1976         if (ca->modeswitch && minRTT > (uint32_t)MSEC_TO_TICKS(10) && maxRTT) {
1977                 ca->beta = (minRTT << 7) / maxRTT;
1978                 if (ca->beta < BETA_MIN)
1979                         ca->beta = BETA_MIN;
1980                 else if (ca->beta > BETA_MAX)
1981                         ca->beta = BETA_MAX;
1982         } else {
1983                 ca->beta = BETA_MIN;
1984                 ca->modeswitch = 1;
1985         }
1986 }
1987
1988 static inline void
1989 htcp_alpha_update(struct htcp *ca)
1990 {
1991         uint32_t minRTT = ca->minRTT;
1992         uint32_t factor = 1;
1993         uint32_t diff = htcp_cong_time(ca);
1994
1995         if (diff > (uint32_t)hz) {
1996                 diff -= hz;
1997                 factor = 1 + (10 * diff + ((diff / 2) * (diff / 2) / hz)) / hz;
1998         }
1999
2000         if (use_rtt_scaling && minRTT) {
2001                 uint32_t scale = (hz << 3) / (10 * minRTT);
2002
2003                 scale = min(max(scale, 1U << 2), 10U << 3);     /* clamping ratio to
2004                                                                  * interval [0.5,10]<<3 */
2005                 factor = (factor << 3) / scale;
2006                 if (!factor)
2007                         factor = 1;
2008         }
2009
2010         ca->alpha = 2 * factor * ((1 << 7) - ca->beta);
2011         if (!ca->alpha)
2012                 ca->alpha = ALPHA_BASE;
2013 }
2014
2015 /* After we have the rtt data to calculate beta, we'd still prefer to wait one
2016  * rtt before we adjust our beta to ensure we are working from a consistent
2017  * data.
2018  *
2019  * This function should be called when we hit a congestion event since only at
2020  * that point do we really have a real sense of maxRTT (the queues en route
2021  * were getting just too full now).
2022  */
2023 static void
2024 htcp_param_update(struct sctp_nets *net)
2025 {
2026         uint32_t minRTT = net->cc_mod.htcp_ca.minRTT;
2027         uint32_t maxRTT = net->cc_mod.htcp_ca.maxRTT;
2028
2029         htcp_beta_update(&net->cc_mod.htcp_ca, minRTT, maxRTT);
2030         htcp_alpha_update(&net->cc_mod.htcp_ca);
2031
2032         /*
2033          * add slowly fading memory for maxRTT to accommodate routing
2034          * changes etc
2035          */
2036         if (minRTT > 0 && maxRTT > minRTT)
2037                 net->cc_mod.htcp_ca.maxRTT = minRTT + ((maxRTT - minRTT) * 95) / 100;
2038 }
2039
2040 static uint32_t
2041 htcp_recalc_ssthresh(struct sctp_nets *net)
2042 {
2043         htcp_param_update(net);
2044         return (max(((net->cwnd / net->mtu * net->cc_mod.htcp_ca.beta) >> 7) * net->mtu, 2U * net->mtu));
2045 }
2046
2047 static void
2048 htcp_cong_avoid(struct sctp_tcb *stcb, struct sctp_nets *net)
2049 {
2050         /*-
2051          * How to handle these functions?
2052          *      if (!tcp_is_cwnd_limited(sk, in_flight)) RRS - good question.
2053          *              return;
2054          */
2055         if (net->cwnd <= net->ssthresh) {
2056                 /* We are in slow start */
2057                 if (net->flight_size + net->net_ack >= net->cwnd) {
2058                         if (net->net_ack > (net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable))) {
2059                                 net->cwnd += (net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable));
2060                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2061                                         sctp_log_cwnd(stcb, net, net->mtu,
2062                                             SCTP_CWND_LOG_FROM_SS);
2063                                 }
2064
2065                         } else {
2066                                 net->cwnd += net->net_ack;
2067                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2068                                         sctp_log_cwnd(stcb, net, net->net_ack,
2069                                             SCTP_CWND_LOG_FROM_SS);
2070                                 }
2071
2072                         }
2073                         sctp_enforce_cwnd_limit(&stcb->asoc, net);
2074                 } else {
2075                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
2076                                 sctp_log_cwnd(stcb, net, net->net_ack,
2077                                     SCTP_CWND_LOG_NOADV_SS);
2078                         }
2079                 }
2080         } else {
2081                 measure_rtt(net);
2082
2083                 /*
2084                  * In dangerous area, increase slowly. In theory this is
2085                  * net->cwnd += alpha / net->cwnd
2086                  */
2087                 /* What is snd_cwnd_cnt?? */
2088                 if (((net->partial_bytes_acked / net->mtu * net->cc_mod.htcp_ca.alpha) >> 7) * net->mtu >= net->cwnd) {
2089                         /*-
2090                          * Does SCTP have a cwnd clamp?
2091                          * if (net->snd_cwnd < net->snd_cwnd_clamp) - Nope (RRS).
2092                          */
2093                         net->cwnd += net->mtu;
2094                         net->partial_bytes_acked = 0;
2095                         sctp_enforce_cwnd_limit(&stcb->asoc, net);
2096                         htcp_alpha_update(&net->cc_mod.htcp_ca);
2097                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2098                                 sctp_log_cwnd(stcb, net, net->mtu,
2099                                     SCTP_CWND_LOG_FROM_CA);
2100                         }
2101                 } else {
2102                         net->partial_bytes_acked += net->net_ack;
2103                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
2104                                 sctp_log_cwnd(stcb, net, net->net_ack,
2105                                     SCTP_CWND_LOG_NOADV_CA);
2106                         }
2107                 }
2108
2109                 net->cc_mod.htcp_ca.bytes_acked = net->mtu;
2110         }
2111 }
2112
2113 #ifdef SCTP_NOT_USED
2114 /* Lower bound on congestion window. */
2115 static uint32_t
2116 htcp_min_cwnd(struct sctp_tcb *stcb, struct sctp_nets *net)
2117 {
2118         return (net->ssthresh);
2119 }
2120 #endif
2121
2122 static void
2123 htcp_init(struct sctp_nets *net)
2124 {
2125         memset(&net->cc_mod.htcp_ca, 0, sizeof(struct htcp));
2126         net->cc_mod.htcp_ca.alpha = ALPHA_BASE;
2127         net->cc_mod.htcp_ca.beta = BETA_MIN;
2128         net->cc_mod.htcp_ca.bytes_acked = net->mtu;
2129         net->cc_mod.htcp_ca.last_cong = sctp_get_tick_count();
2130 }
2131
2132 static void
2133 sctp_htcp_set_initial_cc_param(struct sctp_tcb *stcb, struct sctp_nets *net)
2134 {
2135         /*
2136          * We take the max of the burst limit times a MTU or the
2137          * INITIAL_CWND. We then limit this to 4 MTU's of sending.
2138          */
2139         net->cwnd = min((net->mtu * 4), max((2 * net->mtu), SCTP_INITIAL_CWND));
2140         net->ssthresh = stcb->asoc.peers_rwnd;
2141         sctp_enforce_cwnd_limit(&stcb->asoc, net);
2142         htcp_init(net);
2143
2144         if (SCTP_BASE_SYSCTL(sctp_logging_level) & (SCTP_CWND_MONITOR_ENABLE | SCTP_CWND_LOGGING_ENABLE)) {
2145                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_INITIALIZATION);
2146         }
2147 }
2148
2149 static void
2150 sctp_htcp_cwnd_update_after_sack(struct sctp_tcb *stcb,
2151     struct sctp_association *asoc,
2152     int accum_moved, int reneged_all SCTP_UNUSED, int will_exit)
2153 {
2154         struct sctp_nets *net;
2155
2156         /******************************/
2157         /* update cwnd and Early FR   */
2158         /******************************/
2159         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
2160
2161 #ifdef JANA_CMT_FAST_RECOVERY
2162                 /*
2163                  * CMT fast recovery code. Need to debug.
2164                  */
2165                 if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
2166                         if (SCTP_TSN_GE(asoc->last_acked_seq, net->fast_recovery_tsn) ||
2167                             SCTP_TSN_GE(net->pseudo_cumack, net->fast_recovery_tsn)) {
2168                                 net->will_exit_fast_recovery = 1;
2169                         }
2170                 }
2171 #endif
2172                 /* if nothing was acked on this destination skip it */
2173                 if (net->net_ack == 0) {
2174                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
2175                                 sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
2176                         }
2177                         continue;
2178                 }
2179 #ifdef JANA_CMT_FAST_RECOVERY
2180                 /*
2181                  * CMT fast recovery code
2182                  */
2183                 /*
2184                  * if (sctp_cmt_on_off > 0 && net->fast_retran_loss_recovery
2185                  * && net->will_exit_fast_recovery == 0) { @@@ Do something
2186                  * } else if (sctp_cmt_on_off == 0 &&
2187                  * asoc->fast_retran_loss_recovery && will_exit == 0) {
2188                  */
2189 #endif
2190
2191                 if (asoc->fast_retran_loss_recovery &&
2192                     will_exit == 0 &&
2193                     (asoc->sctp_cmt_on_off == 0)) {
2194                         /*
2195                          * If we are in loss recovery we skip any cwnd
2196                          * update
2197                          */
2198                         return;
2199                 }
2200                 /*
2201                  * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
2202                  * moved.
2203                  */
2204                 if (accum_moved ||
2205                     ((asoc->sctp_cmt_on_off > 0) && net->new_pseudo_cumack)) {
2206                         htcp_cong_avoid(stcb, net);
2207                         measure_achieved_throughput(net);
2208                 } else {
2209                         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
2210                                 sctp_log_cwnd(stcb, net, net->mtu,
2211                                     SCTP_CWND_LOG_NO_CUMACK);
2212                         }
2213                 }
2214         }
2215 }
2216
2217 static void
2218 sctp_htcp_cwnd_update_after_fr(struct sctp_tcb *stcb,
2219     struct sctp_association *asoc)
2220 {
2221         struct sctp_nets *net;
2222
2223         /*
2224          * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off > 0) &&
2225          * (net->fast_retran_loss_recovery == 0)))
2226          */
2227         TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
2228                 if ((asoc->fast_retran_loss_recovery == 0) ||
2229                     (asoc->sctp_cmt_on_off > 0)) {
2230                         /* out of a RFC2582 Fast recovery window? */
2231                         if (net->net_ack > 0) {
2232                                 /*
2233                                  * per section 7.2.3, are there any
2234                                  * destinations that had a fast retransmit
2235                                  * to them. If so what we need to do is
2236                                  * adjust ssthresh and cwnd.
2237                                  */
2238                                 struct sctp_tmit_chunk *lchk;
2239                                 int old_cwnd = net->cwnd;
2240
2241                                 /* JRS - reset as if state were changed */
2242                                 htcp_reset(&net->cc_mod.htcp_ca);
2243                                 net->ssthresh = htcp_recalc_ssthresh(net);
2244                                 net->cwnd = net->ssthresh;
2245                                 sctp_enforce_cwnd_limit(asoc, net);
2246                                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2247                                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
2248                                             SCTP_CWND_LOG_FROM_FR);
2249                                 }
2250                                 lchk = TAILQ_FIRST(&asoc->send_queue);
2251
2252                                 net->partial_bytes_acked = 0;
2253                                 /* Turn on fast recovery window */
2254                                 asoc->fast_retran_loss_recovery = 1;
2255                                 if (lchk == NULL) {
2256                                         /* Mark end of the window */
2257                                         asoc->fast_recovery_tsn = asoc->sending_seq - 1;
2258                                 } else {
2259                                         asoc->fast_recovery_tsn = lchk->rec.data.tsn - 1;
2260                                 }
2261
2262                                 /*
2263                                  * CMT fast recovery -- per destination
2264                                  * recovery variable.
2265                                  */
2266                                 net->fast_retran_loss_recovery = 1;
2267
2268                                 if (lchk == NULL) {
2269                                         /* Mark end of the window */
2270                                         net->fast_recovery_tsn = asoc->sending_seq - 1;
2271                                 } else {
2272                                         net->fast_recovery_tsn = lchk->rec.data.tsn - 1;
2273                                 }
2274
2275                                 sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
2276                                     stcb->sctp_ep, stcb, net,
2277                                     SCTP_FROM_SCTP_CC_FUNCTIONS + SCTP_LOC_3);
2278                                 sctp_timer_start(SCTP_TIMER_TYPE_SEND,
2279                                     stcb->sctp_ep, stcb, net);
2280                         }
2281                 } else if (net->net_ack > 0) {
2282                         /*
2283                          * Mark a peg that we WOULD have done a cwnd
2284                          * reduction but RFC2582 prevented this action.
2285                          */
2286                         SCTP_STAT_INCR(sctps_fastretransinrtt);
2287                 }
2288         }
2289 }
2290
2291 static void
2292 sctp_htcp_cwnd_update_after_timeout(struct sctp_tcb *stcb,
2293     struct sctp_nets *net)
2294 {
2295         int old_cwnd = net->cwnd;
2296
2297         /* JRS - reset as if the state were being changed to timeout */
2298         htcp_reset(&net->cc_mod.htcp_ca);
2299         net->ssthresh = htcp_recalc_ssthresh(net);
2300         net->cwnd = net->mtu;
2301         net->partial_bytes_acked = 0;
2302         if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2303                 sctp_log_cwnd(stcb, net, net->cwnd - old_cwnd, SCTP_CWND_LOG_FROM_RTX);
2304         }
2305 }
2306
2307 static void
2308 sctp_htcp_cwnd_update_after_ecn_echo(struct sctp_tcb *stcb,
2309     struct sctp_nets *net, int in_window, int num_pkt_lost SCTP_UNUSED)
2310 {
2311         int old_cwnd;
2312
2313         old_cwnd = net->cwnd;
2314
2315         /* JRS - reset hctp as if state changed */
2316         if (in_window == 0) {
2317                 htcp_reset(&net->cc_mod.htcp_ca);
2318                 SCTP_STAT_INCR(sctps_ecnereducedcwnd);
2319                 net->ssthresh = htcp_recalc_ssthresh(net);
2320                 if (net->ssthresh < net->mtu) {
2321                         net->ssthresh = net->mtu;
2322                         /* here back off the timer as well, to slow us down */
2323                         net->RTO <<= 1;
2324                 }
2325                 net->cwnd = net->ssthresh;
2326                 sctp_enforce_cwnd_limit(&stcb->asoc, net);
2327                 if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
2328                         sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
2329                 }
2330         }
2331 }
2332
2333 const struct sctp_cc_functions sctp_cc_functions[] = {
2334         {
2335                 .sctp_set_initial_cc_param = sctp_set_initial_cc_param,
2336                 .sctp_cwnd_update_after_sack = sctp_cwnd_update_after_sack,
2337                 .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
2338                 .sctp_cwnd_update_after_fr = sctp_cwnd_update_after_fr,
2339                 .sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
2340                 .sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_after_ecn_echo,
2341                 .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
2342                 .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
2343         },
2344         {
2345                 .sctp_set_initial_cc_param = sctp_set_initial_cc_param,
2346                 .sctp_cwnd_update_after_sack = sctp_hs_cwnd_update_after_sack,
2347                 .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
2348                 .sctp_cwnd_update_after_fr = sctp_hs_cwnd_update_after_fr,
2349                 .sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
2350                 .sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_after_ecn_echo,
2351                 .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
2352                 .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
2353         },
2354         {
2355                 .sctp_set_initial_cc_param = sctp_htcp_set_initial_cc_param,
2356                 .sctp_cwnd_update_after_sack = sctp_htcp_cwnd_update_after_sack,
2357                 .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
2358                 .sctp_cwnd_update_after_fr = sctp_htcp_cwnd_update_after_fr,
2359                 .sctp_cwnd_update_after_timeout = sctp_htcp_cwnd_update_after_timeout,
2360                 .sctp_cwnd_update_after_ecn_echo = sctp_htcp_cwnd_update_after_ecn_echo,
2361                 .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
2362                 .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
2363         },
2364         {
2365                 .sctp_set_initial_cc_param = sctp_set_rtcc_initial_cc_param,
2366                 .sctp_cwnd_update_after_sack = sctp_cwnd_update_rtcc_after_sack,
2367                 .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
2368                 .sctp_cwnd_update_after_fr = sctp_cwnd_update_after_fr,
2369                 .sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
2370                 .sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_rtcc_after_ecn_echo,
2371                 .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
2372                 .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
2373                 .sctp_cwnd_update_packet_transmitted = sctp_cwnd_update_rtcc_packet_transmitted,
2374                 .sctp_cwnd_update_tsn_acknowledged = sctp_cwnd_update_rtcc_tsn_acknowledged,
2375                 .sctp_cwnd_new_transmission_begins = sctp_cwnd_new_rtcc_transmission_begins,
2376                 .sctp_cwnd_prepare_net_for_sack = sctp_cwnd_prepare_rtcc_net_for_sack,
2377                 .sctp_cwnd_socket_option = sctp_cwnd_rtcc_socket_option,
2378                 .sctp_rtt_calculated = sctp_rtt_rtcc_calculated
2379         }
2380 };