sys/netinet/sctp_cc_functions.c

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