sys/netinet/sctp_cc_functions.c

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