/src/usrsctp/usrsctplib/netinet/sctp_cc_functions.c

Source
/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2001-2007, by Cisco Systems, Inc. All rights reserved.
 * Copyright (c) 2008-2012, by Randall Stewart. All rights reserved.
 * Copyright (c) 2008-2012, by Michael Tuexen. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * a) Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * b) Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the distribution.
 *
 * c) Neither the name of Cisco Systems, Inc. nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <netinet/sctp_os.h>
#include <netinet/sctp_var.h>
#include <netinet/sctp_sysctl.h>
#include <netinet/sctp_pcb.h>
#include <netinet/sctp_header.h>
#include <netinet/sctputil.h>
#include <netinet/sctp_output.h>
#include <netinet/sctp_input.h>
#include <netinet/sctp_indata.h>
#include <netinet/sctp_uio.h>
#include <netinet/sctp_timer.h>
#include <netinet/sctp_auth.h>
#include <netinet/sctp_asconf.h>
#if defined(__FreeBSD__) && !defined(__Userspace__)
#include <netinet/sctp_kdtrace.h>
#endif

#if defined(_WIN32) && defined(__MINGW32__)
#include <minmax.h>
#endif

#define SHIFT_MPTCP_MULTI_N 40
#define SHIFT_MPTCP_MULTI_Z 16
#define SHIFT_MPTCP_MULTI 8

#ifdef KDTRACE_HOOKS
#define __dtrace
#else
#define __dtrace __unused
#endif

static void
sctp_enforce_cwnd_limit(struct sctp_association *assoc, struct sctp_nets *net)
{
  if ((assoc->max_cwnd > 0) &&
      (net->cwnd > assoc->max_cwnd) &&
      (net->cwnd > (net->mtu - sizeof(struct sctphdr)))) {
    net->cwnd = assoc->max_cwnd;
    if (net->cwnd < (net->mtu - sizeof(struct sctphdr))) {
      net->cwnd = net->mtu - sizeof(struct sctphdr);
    }
  }
}

static void
sctp_set_initial_cc_param(struct sctp_tcb *stcb, struct sctp_nets *net)
{
  struct sctp_association *assoc;
  uint32_t cwnd_in_mtu;

  assoc = &stcb->asoc;
  cwnd_in_mtu = SCTP_BASE_SYSCTL(sctp_initial_cwnd);
  if (cwnd_in_mtu == 0) {
    /* Using 0 means that the value of RFC 4960 is used. */
    net->cwnd = min((net->mtu * 4), max((2 * net->mtu), SCTP_INITIAL_CWND));
  } else {
    /*
     * We take the minimum of the burst limit and the
     * initial congestion window.
     */
    if ((assoc->max_burst > 0) && (cwnd_in_mtu > assoc->max_burst))
      cwnd_in_mtu = assoc->max_burst;
    net->cwnd = (net->mtu - sizeof(struct sctphdr)) * cwnd_in_mtu;
  }
  if ((stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) ||
      (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV2)) {
    /* In case of resource pooling initialize appropriately */
    net->cwnd /= assoc->numnets;
    if (net->cwnd < (net->mtu - sizeof(struct sctphdr))) {
      net->cwnd = net->mtu - sizeof(struct sctphdr);
    }
  }
  sctp_enforce_cwnd_limit(assoc, net);
  net->ssthresh = assoc->peers_rwnd;
#if defined(__FreeBSD__) && !defined(__Userspace__)
  SDT_PROBE5(sctp, cwnd, net, init,
             stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
             0, net->cwnd);
#endif
  if (SCTP_BASE_SYSCTL(sctp_logging_level) &
      (SCTP_CWND_MONITOR_ENABLE|SCTP_CWND_LOGGING_ENABLE)) {
    sctp_log_cwnd(stcb, net, 0, SCTP_CWND_INITIALIZATION);
  }
}

static void
sctp_cwnd_update_after_fr(struct sctp_tcb *stcb,
                          struct sctp_association *asoc)
{
  struct sctp_nets *net;
  uint32_t t_ssthresh, t_cwnd;
  uint64_t t_ucwnd_sbw;

  /* MT FIXME: Don't compute this over and over again */
  t_ssthresh = 0;
  t_cwnd = 0;
  t_ucwnd_sbw = 0;
  if ((asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) ||
      (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2)) {
    TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
      t_ssthresh += net->ssthresh;
      t_cwnd += net->cwnd;
      if (net->lastsa > 0) {
        t_ucwnd_sbw += (uint64_t)net->cwnd / (uint64_t)net->lastsa;
      }
    }
    if (t_ucwnd_sbw == 0) {
      t_ucwnd_sbw = 1;
    }
  }

  /*-
   * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off > 0) &&
   * (net->fast_retran_loss_recovery == 0)))
   */
  TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
    if ((asoc->fast_retran_loss_recovery == 0) ||
        (asoc->sctp_cmt_on_off > 0)) {
      /* out of a RFC2582 Fast recovery window? */
      if (net->net_ack > 0) {
        /*
         * per section 7.2.3, are there any
         * destinations that had a fast retransmit
         * to them. If so what we need to do is
         * adjust ssthresh and cwnd.
         */
        struct sctp_tmit_chunk *lchk;
        int old_cwnd = net->cwnd;

        if ((asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) ||
            (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2)) {
          if (asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) {
            net->ssthresh = (uint32_t)(((uint64_t)4 *
                                              (uint64_t)net->mtu *
                                              (uint64_t)net->ssthresh) /
                                       (uint64_t)t_ssthresh);
          }
          if (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2) {
            uint32_t srtt;

            srtt = net->lastsa;
            /* lastsa>>3;  we don't need to devide ...*/
            if (srtt == 0) {
              srtt = 1;
            }
            /* Short Version => Equal to Contel Version MBe */
            net->ssthresh = (uint32_t) (((uint64_t)4 *
                                         (uint64_t)net->mtu *
                                         (uint64_t)net->cwnd) /
                                        ((uint64_t)srtt *
                                         t_ucwnd_sbw));
                       /* INCREASE FACTOR */;
          }
          if ((net->cwnd > t_cwnd / 2) &&
              (net->ssthresh < net->cwnd - t_cwnd / 2)) {
            net->ssthresh = net->cwnd - t_cwnd / 2;
          }
          if (net->ssthresh < net->mtu) {
            net->ssthresh = net->mtu;
          }
        } else {
          net->ssthresh = net->cwnd / 2;
          if (net->ssthresh < (net->mtu * 2)) {
            net->ssthresh = 2 * net->mtu;
          }
        }
        net->cwnd = net->ssthresh;
        sctp_enforce_cwnd_limit(asoc, net);
#if defined(__FreeBSD__) && !defined(__Userspace__)
        SDT_PROBE5(sctp, cwnd, net, fr,
                   stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
                   old_cwnd, net->cwnd);
#endif
        if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
          sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
            SCTP_CWND_LOG_FROM_FR);
        }
        lchk = TAILQ_FIRST(&asoc->send_queue);

        net->partial_bytes_acked = 0;
        /* Turn on fast recovery window */
        asoc->fast_retran_loss_recovery = 1;
        if (lchk == NULL) {
          /* Mark end of the window */
          asoc->fast_recovery_tsn = asoc->sending_seq - 1;
        } else {
          asoc->fast_recovery_tsn = lchk->rec.data.tsn - 1;
        }

        /*
         * CMT fast recovery -- per destination
         * recovery variable.
         */
        net->fast_retran_loss_recovery = 1;

        if (lchk == NULL) {
          /* Mark end of the window */
          net->fast_recovery_tsn = asoc->sending_seq - 1;
        } else {
          net->fast_recovery_tsn = lchk->rec.data.tsn - 1;
        }

        sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
            stcb->sctp_ep, stcb, net,
                        SCTP_FROM_SCTP_CC_FUNCTIONS + SCTP_LOC_1);
        sctp_timer_start(SCTP_TIMER_TYPE_SEND,
             stcb->sctp_ep, stcb, net);
      }
    } else if (net->net_ack > 0) {
      /*
       * Mark a peg that we WOULD have done a cwnd
       * reduction but RFC2582 prevented this action.
       */
      SCTP_STAT_INCR(sctps_fastretransinrtt);
    }
  }
}

/* Defines for instantaneous bw decisions */
#define SCTP_INST_LOOSING 1 /* Losing to other flows */
#define SCTP_INST_NEUTRAL 2 /* Neutral, no indication */
#define SCTP_INST_GAINING 3 /* Gaining, step down possible */

#if defined(__FreeBSD__) && !defined(__Userspace__)
static int
cc_bw_same(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw,
           uint64_t rtt_offset, uint64_t vtag, uint8_t inst_ind)
#else
static int
cc_bw_same(struct sctp_tcb *stcb SCTP_UNUSED, struct sctp_nets *net, uint64_t nbw,
           uint64_t rtt_offset, uint8_t inst_ind)
#endif
{
#if defined(__FreeBSD__) && !defined(__Userspace__)
  uint64_t oth __dtrace, probepoint __dtrace;
#endif

#if defined(__FreeBSD__) && !defined(__Userspace__)
  probepoint = (((uint64_t)net->cwnd) << 32);
#endif
  if (net->rtt > net->cc_mod.rtcc.lbw_rtt + rtt_offset) {
    /*
     * rtt increased
     * we don't update bw.. so we don't
     * update the rtt either.
     */
#if defined(__FreeBSD__) && !defined(__Userspace__)
    /* Probe point 5 */
    probepoint |=  ((5 << 16) | 1);
    SDT_PROBE5(sctp, cwnd, net, rttvar,
               vtag,
               ((net->cc_mod.rtcc.lbw << 32) | nbw),
               ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
               net->flight_size,
               probepoint);
#endif
    if ((net->cc_mod.rtcc.steady_step) && (inst_ind != SCTP_INST_LOOSING)) {
      if (net->cc_mod.rtcc.last_step_state == 5)
        net->cc_mod.rtcc.step_cnt++;
      else
        net->cc_mod.rtcc.step_cnt = 1;
      net->cc_mod.rtcc.last_step_state = 5;
      if ((net->cc_mod.rtcc.step_cnt == net->cc_mod.rtcc.steady_step) ||
          ((net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step) &&
           ((net->cc_mod.rtcc.step_cnt % net->cc_mod.rtcc.steady_step) == 0))) {
        /* Try a step down */
#if defined(__FreeBSD__) && !defined(__Userspace__)
        oth = net->cc_mod.rtcc.vol_reduce;
        oth <<= 16;
        oth |= net->cc_mod.rtcc.step_cnt;
        oth <<= 16;
        oth |= net->cc_mod.rtcc.last_step_state;
        SDT_PROBE5(sctp, cwnd, net, rttstep,
                   vtag,
                   ((net->cc_mod.rtcc.lbw << 32) | nbw),
                   ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
                   oth,
                   probepoint);
#endif
        if (net->cwnd > (4 * net->mtu)) {
          net->cwnd -= net->mtu;
          net->cc_mod.rtcc.vol_reduce++;
        } else {
          net->cc_mod.rtcc.step_cnt = 0;
        }
      }
    }
    return (1);
  }
  if (net->rtt < net->cc_mod.rtcc.lbw_rtt-rtt_offset) {
    /*
     * rtt decreased, there could be more room.
     * we update both the bw and the rtt here to
     * lock this in as a good step down.
     */
#if defined(__FreeBSD__) && !defined(__Userspace__)
    /* Probe point 6 */
    probepoint |=  ((6 << 16) | 0);
    SDT_PROBE5(sctp, cwnd, net, rttvar,
               vtag,
               ((net->cc_mod.rtcc.lbw << 32) | nbw),
               ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
               net->flight_size,
               probepoint);
#endif
    if (net->cc_mod.rtcc.steady_step) {
#if defined(__FreeBSD__) && !defined(__Userspace__)
      oth = net->cc_mod.rtcc.vol_reduce;
      oth <<= 16;
      oth |= net->cc_mod.rtcc.step_cnt;
      oth <<= 16;
      oth |= net->cc_mod.rtcc.last_step_state;
      SDT_PROBE5(sctp, cwnd, net, rttstep,
                 vtag,
                 ((net->cc_mod.rtcc.lbw << 32) | nbw),
                 ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
                 oth,
                 probepoint);
#endif
      if ((net->cc_mod.rtcc.last_step_state == 5) &&
          (net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step)) {
        /* Step down worked */
        net->cc_mod.rtcc.step_cnt = 0;
        return (1);
      } else {
        net->cc_mod.rtcc.last_step_state = 6;
        net->cc_mod.rtcc.step_cnt = 0;
      }
    }
    net->cc_mod.rtcc.lbw = nbw;
    net->cc_mod.rtcc.lbw_rtt = net->rtt;
    net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
    if (inst_ind == SCTP_INST_GAINING)
      return (1);
    else if (inst_ind == SCTP_INST_NEUTRAL)
      return (1);
    else
      return (0);
  }
  /* Ok bw and rtt remained the same .. no update to any
   */
#if defined(__FreeBSD__) && !defined(__Userspace__)
  /* Probe point 7 */
  probepoint |=  ((7 << 16) | net->cc_mod.rtcc.ret_from_eq);
  SDT_PROBE5(sctp, cwnd, net, rttvar,
             vtag,
             ((net->cc_mod.rtcc.lbw << 32) | nbw),
             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
             net->flight_size,
             probepoint);
#endif
  if ((net->cc_mod.rtcc.steady_step) && (inst_ind != SCTP_INST_LOOSING)) {
    if (net->cc_mod.rtcc.last_step_state == 5)
      net->cc_mod.rtcc.step_cnt++;
    else
      net->cc_mod.rtcc.step_cnt = 1;
    net->cc_mod.rtcc.last_step_state = 5;
    if ((net->cc_mod.rtcc.step_cnt == net->cc_mod.rtcc.steady_step) ||
        ((net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step) &&
         ((net->cc_mod.rtcc.step_cnt % net->cc_mod.rtcc.steady_step) == 0))) {
      /* Try a step down */
      if (net->cwnd > (4 * net->mtu)) {
        net->cwnd -= net->mtu;
        net->cc_mod.rtcc.vol_reduce++;
        return (1);
      } else {
        net->cc_mod.rtcc.step_cnt = 0;
      }
    }
  }
  if (inst_ind == SCTP_INST_GAINING)
    return (1);
  else if (inst_ind == SCTP_INST_NEUTRAL)
    return (1);
  else
    return ((int)net->cc_mod.rtcc.ret_from_eq);
}

#if defined(__FreeBSD__) && !defined(__Userspace__)
static int
cc_bw_decrease(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw, uint64_t rtt_offset,
               uint64_t vtag, uint8_t inst_ind)
#else
static int
cc_bw_decrease(struct sctp_tcb *stcb SCTP_UNUSED, struct sctp_nets *net, uint64_t nbw, uint64_t rtt_offset,
               uint8_t inst_ind)
#endif
{
#if defined(__FreeBSD__) && !defined(__Userspace__)
  uint64_t oth __dtrace, probepoint __dtrace;
#endif

  /* Bandwidth decreased.*/
#if defined(__FreeBSD__) && !defined(__Userspace__)
  probepoint = (((uint64_t)net->cwnd) << 32);
#endif
  if (net->rtt  > net->cc_mod.rtcc.lbw_rtt+rtt_offset) {
    /* rtt increased */
    /* Did we add more */
    if ((net->cwnd > net->cc_mod.rtcc.cwnd_at_bw_set) &&
        (inst_ind != SCTP_INST_LOOSING)) {
      /* We caused it maybe.. back off? */
#if defined(__FreeBSD__) && !defined(__Userspace__)
      /* PROBE POINT 1 */
      probepoint |=  ((1 << 16) | 1);
      SDT_PROBE5(sctp, cwnd, net, rttvar,
                 vtag,
                 ((net->cc_mod.rtcc.lbw << 32) | nbw),
                 ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
                 net->flight_size,
                 probepoint);
#endif
      if (net->cc_mod.rtcc.ret_from_eq) {
        /* Switch over to CA if we are less aggressive */
        net->ssthresh = net->cwnd-1;
        net->partial_bytes_acked = 0;
      }
      return (1);
    }
#if defined(__FreeBSD__) && !defined(__Userspace__)
    /* Probe point 2 */
    probepoint |=  ((2 << 16) | 0);
    SDT_PROBE5(sctp, cwnd, net, rttvar,
               vtag,
               ((net->cc_mod.rtcc.lbw << 32) | nbw),
               ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
               net->flight_size,
               probepoint);
#endif
    /* Someone else - fight for more? */
    if (net->cc_mod.rtcc.steady_step) {
#if defined(__FreeBSD__) && !defined(__Userspace__)
      oth = net->cc_mod.rtcc.vol_reduce;
      oth <<= 16;
      oth |= net->cc_mod.rtcc.step_cnt;
      oth <<= 16;
      oth |= net->cc_mod.rtcc.last_step_state;
      SDT_PROBE5(sctp, cwnd, net, rttstep,
                 vtag,
                 ((net->cc_mod.rtcc.lbw << 32) | nbw),
                 ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
                 oth,
          probepoint);
#endif
      /* Did we voluntarily give up some? if so take
       * one back please
       */
      if ((net->cc_mod.rtcc.vol_reduce) &&
          (inst_ind != SCTP_INST_GAINING)) {
        net->cwnd += net->mtu;
        sctp_enforce_cwnd_limit(&stcb->asoc, net);
        net->cc_mod.rtcc.vol_reduce--;
      }
      net->cc_mod.rtcc.last_step_state = 2;
      net->cc_mod.rtcc.step_cnt = 0;
    }
    goto out_decision;
  } else  if (net->rtt  < net->cc_mod.rtcc.lbw_rtt-rtt_offset) {
    /* bw & rtt decreased */
#if defined(__FreeBSD__) && !defined(__Userspace__)
    /* Probe point 3 */
    probepoint |=  ((3 << 16) | 0);
    SDT_PROBE5(sctp, cwnd, net, rttvar,
               vtag,
               ((net->cc_mod.rtcc.lbw << 32) | nbw),
               ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
               net->flight_size,
               probepoint);
#endif
    if (net->cc_mod.rtcc.steady_step) {
#if defined(__FreeBSD__) && !defined(__Userspace__)
      oth = net->cc_mod.rtcc.vol_reduce;
      oth <<= 16;
      oth |= net->cc_mod.rtcc.step_cnt;
      oth <<= 16;
      oth |= net->cc_mod.rtcc.last_step_state;
      SDT_PROBE5(sctp, cwnd, net, rttstep,
                 vtag,
                 ((net->cc_mod.rtcc.lbw << 32) | nbw),
                 ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
                 oth,
                 probepoint);
#endif
      if ((net->cc_mod.rtcc.vol_reduce) &&
          (inst_ind != SCTP_INST_GAINING)) {
        net->cwnd += net->mtu;
        sctp_enforce_cwnd_limit(&stcb->asoc, net);
        net->cc_mod.rtcc.vol_reduce--;
      }
      net->cc_mod.rtcc.last_step_state = 3;
      net->cc_mod.rtcc.step_cnt = 0;
    }
    goto out_decision;
  }
  /* The bw decreased but rtt stayed the same */
#if defined(__FreeBSD__) && !defined(__Userspace__)
  /* Probe point 4 */
  probepoint |=  ((4 << 16) | 0);
  SDT_PROBE5(sctp, cwnd, net, rttvar,
             vtag,
             ((net->cc_mod.rtcc.lbw << 32) | nbw),
             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
             net->flight_size,
             probepoint);
#endif
  if (net->cc_mod.rtcc.steady_step) {
#if defined(__FreeBSD__) && !defined(__Userspace__)
    oth = net->cc_mod.rtcc.vol_reduce;
    oth <<= 16;
    oth |= net->cc_mod.rtcc.step_cnt;
    oth <<= 16;
    oth |= net->cc_mod.rtcc.last_step_state;
    SDT_PROBE5(sctp, cwnd, net, rttstep,
               vtag,
               ((net->cc_mod.rtcc.lbw << 32) | nbw),
               ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
               oth,
               probepoint);
#endif
    if ((net->cc_mod.rtcc.vol_reduce) &&
        (inst_ind != SCTP_INST_GAINING)) {
      net->cwnd += net->mtu;
      sctp_enforce_cwnd_limit(&stcb->asoc, net);
      net->cc_mod.rtcc.vol_reduce--;
    }
    net->cc_mod.rtcc.last_step_state = 4;
    net->cc_mod.rtcc.step_cnt = 0;
  }
out_decision:
  net->cc_mod.rtcc.lbw = nbw;
  net->cc_mod.rtcc.lbw_rtt = net->rtt;
  net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
  if (inst_ind == SCTP_INST_GAINING) {
    return (1);
  } else {
    return (0);
  }
}

#if defined(__FreeBSD__) && !defined(__Userspace__)
static int
cc_bw_increase(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw, uint64_t vtag)
#else
static int
cc_bw_increase(struct sctp_tcb *stcb SCTP_UNUSED, struct sctp_nets *net, uint64_t nbw)
#endif
{
#if defined(__FreeBSD__) && !defined(__Userspace__)
  uint64_t oth __dtrace, probepoint __dtrace;

#endif
  /* BW increased, so update and
   * return 0, since all actions in
   * our table say to do the normal CC
   * update. Note that we pay no attention to
   * the inst_ind since our overall sum is increasing.
   */
#if defined(__FreeBSD__) && !defined(__Userspace__)
  /* PROBE POINT 0 */
  probepoint = (((uint64_t)net->cwnd) << 32);
  SDT_PROBE5(sctp, cwnd, net, rttvar,
             vtag,
             ((net->cc_mod.rtcc.lbw << 32) | nbw),
             ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
             net->flight_size,
             probepoint);
#endif
  if (net->cc_mod.rtcc.steady_step) {
#if defined(__FreeBSD__) && !defined(__Userspace__)
    oth = net->cc_mod.rtcc.vol_reduce;
    oth <<= 16;
    oth |= net->cc_mod.rtcc.step_cnt;
    oth <<= 16;
    oth |= net->cc_mod.rtcc.last_step_state;
    SDT_PROBE5(sctp, cwnd, net, rttstep,
               vtag,
               ((net->cc_mod.rtcc.lbw << 32) | nbw),
               ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
               oth,
               probepoint);
#endif
    net->cc_mod.rtcc.last_step_state = 0;
    net->cc_mod.rtcc.step_cnt = 0;
    net->cc_mod.rtcc.vol_reduce = 0;
  }
  net->cc_mod.rtcc.lbw = nbw;
  net->cc_mod.rtcc.lbw_rtt = net->rtt;
  net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
  return (0);
}

/* RTCC Algorithm to limit growth of cwnd, return
 * true if you want to NOT allow cwnd growth
 */
static int
cc_bw_limit(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw)
{
  uint64_t bw_offset, rtt_offset;
#if defined(__FreeBSD__) && !defined(__Userspace__)
  uint64_t probepoint __dtrace, rtt, vtag;
#endif
  uint64_t bytes_for_this_rtt, inst_bw;
  uint64_t div, inst_off;
  int bw_shift;
  uint8_t inst_ind;
  int ret;
  /*-
   * Here we need to see if we want
   * to limit cwnd growth due to increase
   * in overall rtt but no increase in bw.
   * We use the following table to figure
   * out what we should do. When we return
   * 0, cc update goes on as planned. If we
   * return 1, then no cc update happens and cwnd
   * stays where it is at.
   * ----------------------------------
   *   BW    |    RTT   | Action
   * *********************************
   *   INC   |    INC   | return 0
   * ----------------------------------
   *   INC   |    SAME  | return 0
   * ----------------------------------
   *   INC   |    DECR  | return 0
   * ----------------------------------
   *   SAME  |    INC   | return 1
   * ----------------------------------
   *   SAME  |    SAME  | return 1
   * ----------------------------------
   *   SAME  |    DECR  | return 0
   * ----------------------------------
   *   DECR  |    INC   | return 0 or 1 based on if we caused.
   * ----------------------------------
   *   DECR  |    SAME  | return 0
   * ----------------------------------
   *   DECR  |    DECR  | return 0
   * ----------------------------------
   *
   * We are a bit fuzz on what an increase or
   * decrease is. For BW it is the same if
   * it did not change within 1/64th. For
   * RTT it stayed the same if it did not
   * change within 1/32nd
   */
  bw_shift = SCTP_BASE_SYSCTL(sctp_rttvar_bw);
#if defined(__FreeBSD__) && !defined(__Userspace__)
  rtt = stcb->asoc.my_vtag;
  vtag = (rtt << 32) | (((uint32_t)(stcb->sctp_ep->sctp_lport)) << 16) | (stcb->rport);
  probepoint = (((uint64_t)net->cwnd) << 32);
  rtt = net->rtt;
#endif
  if (net->cc_mod.rtcc.rtt_set_this_sack) {
    net->cc_mod.rtcc.rtt_set_this_sack = 0;
    bytes_for_this_rtt = net->cc_mod.rtcc.bw_bytes - net->cc_mod.rtcc.bw_bytes_at_last_rttc;
    net->cc_mod.rtcc.bw_bytes_at_last_rttc = net->cc_mod.rtcc.bw_bytes;
    if (net->rtt) {
      div = net->rtt / 1000;
      if (div) {
        inst_bw = bytes_for_this_rtt / div;
        inst_off = inst_bw >> bw_shift;
        if (inst_bw > nbw)
          inst_ind = SCTP_INST_GAINING;
        else if ((inst_bw+inst_off) < nbw)
          inst_ind = SCTP_INST_LOOSING;
        else
          inst_ind = SCTP_INST_NEUTRAL;
#if defined(__FreeBSD__) && !defined(__Userspace__)
        probepoint |=  ((0xb << 16) | inst_ind);
#endif
      } else {
        inst_ind = net->cc_mod.rtcc.last_inst_ind;
#if defined(__FreeBSD__) && !defined(__Userspace__)
        inst_bw = bytes_for_this_rtt / (uint64_t)(net->rtt);
        /* Can't determine do not change */
        probepoint |=  ((0xc << 16) | inst_ind);
#endif
      }
    } else {
      inst_ind = net->cc_mod.rtcc.last_inst_ind;
#if defined(__FreeBSD__) && !defined(__Userspace__)
      inst_bw = bytes_for_this_rtt;
      /* Can't determine do not change */
      probepoint |=  ((0xd << 16) | inst_ind);
#endif
    }
#if defined(__FreeBSD__) && !defined(__Userspace__)
    SDT_PROBE5(sctp, cwnd, net, rttvar,
               vtag,
               ((nbw << 32) | inst_bw),
               ((net->cc_mod.rtcc.lbw_rtt << 32) | rtt),
               net->flight_size,
               probepoint);
#endif
  } else {
    /* No rtt measurement, use last one */
    inst_ind = net->cc_mod.rtcc.last_inst_ind;
  }
  bw_offset = net->cc_mod.rtcc.lbw >> bw_shift;
  if (nbw > net->cc_mod.rtcc.lbw + bw_offset) {
#if defined(__FreeBSD__) && !defined(__Userspace__)
    ret = cc_bw_increase(stcb, net, nbw, vtag);
#else
    ret = cc_bw_increase(stcb, net, nbw);
#endif
    goto out;
  }
  rtt_offset = net->cc_mod.rtcc.lbw_rtt >> SCTP_BASE_SYSCTL(sctp_rttvar_rtt);
  if (nbw < net->cc_mod.rtcc.lbw - bw_offset) {
#if defined(__FreeBSD__) && !defined(__Userspace__)
    ret = cc_bw_decrease(stcb, net, nbw, rtt_offset, vtag, inst_ind);
#else
    ret = cc_bw_decrease(stcb, net, nbw, rtt_offset, inst_ind);
#endif
    goto out;
  }
  /* If we reach here then
   * we are in a situation where
   * the bw stayed the same.
   */
#if defined(__FreeBSD__) && !defined(__Userspace__)
  ret = cc_bw_same(stcb, net, nbw, rtt_offset, vtag, inst_ind);
#else
  ret = cc_bw_same(stcb, net, nbw, rtt_offset, inst_ind);
#endif
out:
  net->cc_mod.rtcc.last_inst_ind = inst_ind;
  return (ret);
}

static void
sctp_cwnd_update_after_sack_common(struct sctp_tcb *stcb,
           struct sctp_association *asoc,
           int accum_moved, int reneged_all SCTP_UNUSED, int will_exit, int use_rtcc)
{
  struct sctp_nets *net;
#if defined(__FreeBSD__) && !defined(__Userspace__)
  int old_cwnd __dtrace;
#endif
  uint32_t t_ssthresh, incr;
  uint64_t t_ucwnd_sbw;
  uint64_t t_path_mptcp;
  uint64_t mptcp_like_alpha;
  uint32_t srtt;
  uint64_t max_path;

  /* MT FIXME: Don't compute this over and over again */
  t_ssthresh = 0;
  t_ucwnd_sbw = 0;
  t_path_mptcp = 0;
  mptcp_like_alpha = 1;
  if ((stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) ||
      (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV2) ||
      (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_MPTCP)) {
    max_path = 0;
    TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
      t_ssthresh += net->ssthresh;
      /* lastsa>>3;  we don't need to devide ...*/
      srtt = net->lastsa;
      if (srtt > 0) {
        uint64_t tmp;

        t_ucwnd_sbw += (uint64_t)net->cwnd / (uint64_t)srtt;
        t_path_mptcp += (((uint64_t)net->cwnd) << SHIFT_MPTCP_MULTI_Z) /
                        (((uint64_t)net->mtu) * (uint64_t)srtt);
        tmp = (((uint64_t)net->cwnd) << SHIFT_MPTCP_MULTI_N) /
              ((uint64_t)net->mtu * (uint64_t)(srtt * srtt));
        if (tmp > max_path) {
          max_path = tmp;
        }
      }
    }
    if (t_path_mptcp > 0) {
      mptcp_like_alpha = max_path / (t_path_mptcp * t_path_mptcp);
    } else {
      mptcp_like_alpha = 1;
    }
  }
  if (t_ssthresh == 0) {
    t_ssthresh = 1;
  }
  if (t_ucwnd_sbw == 0) {
    t_ucwnd_sbw = 1;
  }
  /******************************/
  /* update cwnd and Early FR   */
  /******************************/
  TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
#ifdef JANA_CMT_FAST_RECOVERY
    /*
     * CMT fast recovery code. Need to debug.
     */
    if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
      if (SCTP_TSN_GE(asoc->last_acked_seq, net->fast_recovery_tsn) ||
          SCTP_TSN_GE(net->pseudo_cumack,net->fast_recovery_tsn)) {
        net->will_exit_fast_recovery = 1;
      }
    }
#endif
    /* if nothing was acked on this destination skip it */
    if (net->net_ack == 0) {
      if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
        sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
      }
      continue;
    }
#ifdef JANA_CMT_FAST_RECOVERY
    /* CMT fast recovery code
     */
    /*
      if (sctp_cmt_on_off > 0 && net->fast_retran_loss_recovery && net->will_exit_fast_recovery == 0) {
      @@@ Do something
      }
      else if (sctp_cmt_on_off == 0 && asoc->fast_retran_loss_recovery && will_exit == 0) {
    */
#endif

    if (asoc->fast_retran_loss_recovery &&
        (will_exit == 0) &&
        (asoc->sctp_cmt_on_off == 0)) {
      /*
       * If we are in loss recovery we skip any cwnd
       * update
       */
      return;
    }
    /*
     * Did any measurements go on for this network?
     */
    if (use_rtcc && (net->cc_mod.rtcc.tls_needs_set > 0)) {
      uint64_t nbw;
      /*
       * At this point our bw_bytes has been updated
       * by incoming sack information.
       *
       * But our bw may not yet be set.
       *
       */
      if ((net->cc_mod.rtcc.new_tot_time/1000) > 0) {
        nbw = net->cc_mod.rtcc.bw_bytes/(net->cc_mod.rtcc.new_tot_time/1000);
      } else {
        nbw = net->cc_mod.rtcc.bw_bytes;
      }
      if (net->cc_mod.rtcc.lbw) {
        if (cc_bw_limit(stcb, net, nbw)) {
          /* Hold here, no update */
          continue;
        }
      } else {
#if defined(__FreeBSD__) && !defined(__Userspace__)
        uint64_t vtag __dtrace, probepoint __dtrace;

        probepoint = (((uint64_t)net->cwnd) << 32);
        probepoint |=  ((0xa << 16) | 0);
        vtag = (net->rtt << 32) |
          (((uint32_t)(stcb->sctp_ep->sctp_lport)) << 16) |
          (stcb->rport);

        SDT_PROBE5(sctp, cwnd, net, rttvar,
                   vtag,
                   nbw,
                   ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
                   net->flight_size,
                   probepoint);
#endif
        net->cc_mod.rtcc.lbw = nbw;
        net->cc_mod.rtcc.lbw_rtt = net->rtt;
        if (net->cc_mod.rtcc.rtt_set_this_sack) {
          net->cc_mod.rtcc.rtt_set_this_sack = 0;
          net->cc_mod.rtcc.bw_bytes_at_last_rttc = net->cc_mod.rtcc.bw_bytes;
        }
      }
    }
    /*
     * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
     * moved.
     */
    if (accum_moved ||
        ((asoc->sctp_cmt_on_off > 0) && net->new_pseudo_cumack)) {
      /* If the cumulative ack moved we can proceed */
      if (net->cwnd <= net->ssthresh) {
        /* We are in slow start */
        if (net->flight_size + net->net_ack >= net->cwnd) {
          uint32_t limit;

#if defined(__FreeBSD__) && !defined(__Userspace__)
          old_cwnd = net->cwnd;
#endif
          switch (asoc->sctp_cmt_on_off) {
          case SCTP_CMT_RPV1:
            limit = (uint32_t)(((uint64_t)net->mtu *
                                (uint64_t)SCTP_BASE_SYSCTL(sctp_L2_abc_variable) *
                                (uint64_t)net->ssthresh) /
                               (uint64_t)t_ssthresh);
            incr = (uint32_t)(((uint64_t)net->net_ack *
                               (uint64_t)net->ssthresh) /
                              (uint64_t)t_ssthresh);
            if (incr > limit) {
              incr = limit;
            }
            if (incr == 0) {
              incr = 1;
            }
            break;
          case SCTP_CMT_RPV2:
            /* lastsa>>3;  we don't need to divide ...*/
            srtt = net->lastsa;
            if (srtt == 0) {
              srtt = 1;
            }
            limit = (uint32_t)(((uint64_t)net->mtu *
                                (uint64_t)SCTP_BASE_SYSCTL(sctp_L2_abc_variable) *
                                (uint64_t)net->cwnd) /
                               ((uint64_t)srtt * t_ucwnd_sbw));
                               /* INCREASE FACTOR */
            incr = (uint32_t)(((uint64_t)net->net_ack *
                               (uint64_t)net->cwnd) /
                              ((uint64_t)srtt * t_ucwnd_sbw));
                              /* INCREASE FACTOR */
            if (incr > limit) {
              incr = limit;
            }
            if (incr == 0) {
              incr = 1;
            }
            break;
          case SCTP_CMT_MPTCP:
            limit = (uint32_t)(((uint64_t)net->mtu *
                                mptcp_like_alpha *
                                (uint64_t)SCTP_BASE_SYSCTL(sctp_L2_abc_variable)) >>
                               SHIFT_MPTCP_MULTI);
            incr  = (uint32_t)(((uint64_t)net->net_ack *
                                mptcp_like_alpha) >>
                               SHIFT_MPTCP_MULTI);
            if (incr > limit) {
              incr = limit;
            }
            if (incr > net->net_ack) {
              incr = net->net_ack;
            }
            if (incr > net->mtu) {
              incr = net->mtu;
            }
            break;
          default:
            incr = net->net_ack;
            if (incr > net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable)) {
              incr = net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable);
            }
            break;
          }
          net->cwnd += incr;
          sctp_enforce_cwnd_limit(asoc, net);
          if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
            sctp_log_cwnd(stcb, net, incr,
                          SCTP_CWND_LOG_FROM_SS);
          }
#if defined(__FreeBSD__) && !defined(__Userspace__)
          SDT_PROBE5(sctp, cwnd, net, ack,
                     stcb->asoc.my_vtag,
                     ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
                     net,
                     old_cwnd, net->cwnd);
#endif
        } else {
          if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
            sctp_log_cwnd(stcb, net, net->net_ack,
                    SCTP_CWND_LOG_NOADV_SS);
          }
        }
      } else {
        /* We are in congestion avoidance */
        /*
         * Add to pba
         */
              net->partial_bytes_acked += net->net_ack;

        if ((net->flight_size + net->net_ack >= net->cwnd) &&
            (net->partial_bytes_acked >= net->cwnd)) {
          net->partial_bytes_acked -= net->cwnd;
#if defined(__FreeBSD__) && !defined(__Userspace__)
          old_cwnd = net->cwnd;
#endif
          switch (asoc->sctp_cmt_on_off) {
          case SCTP_CMT_RPV1:
            incr = (uint32_t)(((uint64_t)net->mtu *
                               (uint64_t)net->ssthresh) /
                              (uint64_t)t_ssthresh);
            if (incr == 0) {
              incr = 1;
            }
            break;
          case SCTP_CMT_RPV2:
            /* lastsa>>3;  we don't need to divide ... */
            srtt = net->lastsa;
            if (srtt == 0) {
              srtt = 1;
            }
            incr = (uint32_t)((uint64_t)net->mtu *
                              (uint64_t)net->cwnd /
                              ((uint64_t)srtt *
                               t_ucwnd_sbw));
                              /* INCREASE FACTOR */
            if (incr == 0) {
              incr = 1;
            }
            break;
          case SCTP_CMT_MPTCP:
            incr = (uint32_t)((mptcp_like_alpha *
                               (uint64_t) net->cwnd) >>
                              SHIFT_MPTCP_MULTI);
            if (incr > net->mtu) {
              incr = net->mtu;
            }
            break;
          default:
            incr = net->mtu;
            break;
          }
          net->cwnd += incr;
          sctp_enforce_cwnd_limit(asoc, net);
#if defined(__FreeBSD__) && !defined(__Userspace__)
          SDT_PROBE5(sctp, cwnd, net, ack,
                     stcb->asoc.my_vtag,
                     ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
                     net,
                     old_cwnd, net->cwnd);
#endif
          if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
            sctp_log_cwnd(stcb, net, net->mtu,
                    SCTP_CWND_LOG_FROM_CA);
          }
        } else {
          if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
            sctp_log_cwnd(stcb, net, net->net_ack,
                    SCTP_CWND_LOG_NOADV_CA);
          }
        }
      }
    } else {
      if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
        sctp_log_cwnd(stcb, net, net->mtu,
                SCTP_CWND_LOG_NO_CUMACK);
      }
    }
  }
}

#if defined(__FreeBSD__) && !defined(__Userspace__)
static void
sctp_cwnd_update_exit_pf_common(struct sctp_tcb *stcb, struct sctp_nets *net)
#else
static void
sctp_cwnd_update_exit_pf_common(struct sctp_tcb *stcb SCTP_UNUSED, struct sctp_nets *net)
#endif
{
#if defined(__FreeBSD__) && !defined(__Userspace__)
  int old_cwnd __dtrace;

  old_cwnd = net->cwnd;
#endif
  net->cwnd = net->mtu;
#if defined(__FreeBSD__) && !defined(__Userspace__)
  SDT_PROBE5(sctp, cwnd, net, ack,
             stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
             old_cwnd, net->cwnd);
#endif
  SCTPDBG(SCTP_DEBUG_INDATA1, "Destination %p moved from PF to reachable with cwnd %d.\n",
          (void *)net, net->cwnd);
}

static void
sctp_cwnd_update_after_timeout(struct sctp_tcb *stcb, struct sctp_nets *net)
{
  int old_cwnd = net->cwnd;
  uint32_t t_ssthresh, t_cwnd;
  uint64_t t_ucwnd_sbw;

  /* MT FIXME: Don't compute this over and over again */
  t_ssthresh = 0;
  t_cwnd = 0;
  if ((stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) ||
      (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV2)) {
    struct sctp_nets *lnet;
    uint32_t srtt;

    t_ucwnd_sbw = 0;
    TAILQ_FOREACH(lnet, &stcb->asoc.nets, sctp_next) {
      t_ssthresh += lnet->ssthresh;
      t_cwnd += lnet->cwnd;
      srtt = lnet->lastsa;
      /* lastsa>>3;  we don't need to divide ... */
      if (srtt > 0) {
        t_ucwnd_sbw += (uint64_t)lnet->cwnd / (uint64_t)srtt;
      }
    }
    if (t_ssthresh < 1) {
      t_ssthresh = 1;
    }
    if (t_ucwnd_sbw < 1) {
      t_ucwnd_sbw = 1;
    }
    if (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) {
      net->ssthresh = (uint32_t)(((uint64_t)4 *
                                  (uint64_t)net->mtu *
                                  (uint64_t)net->ssthresh) /
                                 (uint64_t)t_ssthresh);
    } else {
      uint64_t cc_delta;

      srtt = net->lastsa;
      /* lastsa>>3;  we don't need to divide ... */
      if (srtt == 0) {
        srtt = 1;
      }
      cc_delta = t_ucwnd_sbw * (uint64_t)srtt / 2;
      if (cc_delta < t_cwnd) {
        net->ssthresh = (uint32_t)((uint64_t)t_cwnd - cc_delta);
      } else {
        net->ssthresh  = net->mtu;
      }
    }
    if ((net->cwnd > t_cwnd / 2) &&
        (net->ssthresh < net->cwnd - t_cwnd / 2)) {
      net->ssthresh = net->cwnd - t_cwnd / 2;
    }
    if (net->ssthresh < net->mtu) {
      net->ssthresh = net->mtu;
    }
  } else {
    net->ssthresh = max(net->cwnd / 2, 4 * net->mtu);
  }
  net->cwnd = net->mtu;
  net->partial_bytes_acked = 0;
#if defined(__FreeBSD__) && !defined(__Userspace__)
  SDT_PROBE5(sctp, cwnd, net, to,
             stcb->asoc.my_vtag,
             ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
             net,
             old_cwnd, net->cwnd);
#endif
  if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
    sctp_log_cwnd(stcb, net, net->cwnd - old_cwnd, SCTP_CWND_LOG_FROM_RTX);
  }
}

static void
sctp_cwnd_update_after_ecn_echo_common(struct sctp_tcb *stcb, struct sctp_nets *net,
                                       int in_window, int num_pkt_lost, int use_rtcc)
{
  int old_cwnd = net->cwnd;
  if ((use_rtcc) && (net->lan_type == SCTP_LAN_LOCAL) && (net->cc_mod.rtcc.use_dccc_ecn)) {
    /* Data center Congestion Control */
    if (in_window == 0) {
      /* Go to CA with the cwnd at the point we sent
       * the TSN that was marked with a CE.
       */
      if (net->ecn_prev_cwnd < net->cwnd) {
        /* Restore to prev cwnd */
        net->cwnd = net->ecn_prev_cwnd - (net->mtu * num_pkt_lost);
      } else {
        /* Just cut in 1/2 */
        net->cwnd /= 2;
      }
      /* Drop to CA */
      net->ssthresh = net->cwnd - (num_pkt_lost * net->mtu);
      if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
        sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
      }
    } else {
      /* Further tuning down required over the drastic original cut */
      net->ssthresh -= (net->mtu * num_pkt_lost);
      net->cwnd -= (net->mtu * num_pkt_lost);
      if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
        sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
      }
    }
    SCTP_STAT_INCR(sctps_ecnereducedcwnd);
  } else {
    if (in_window == 0) {
      SCTP_STAT_INCR(sctps_ecnereducedcwnd);
      net->ssthresh = net->cwnd / 2;
      if (net->ssthresh < net->mtu) {
        net->ssthresh = net->mtu;
        /* here back off the timer as well, to slow us down */
        net->RTO <<= 1;
      }
      net->cwnd = net->ssthresh;
#if defined(__FreeBSD__) && !defined(__Userspace__)
      SDT_PROBE5(sctp, cwnd, net, ecn,
                 stcb->asoc.my_vtag,
                 ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
                 net,
                 old_cwnd, net->cwnd);
#endif
      if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
        sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
      }
    }
  }

}

static void
sctp_cwnd_update_after_packet_dropped(struct sctp_tcb *stcb,
  struct sctp_nets *net, struct sctp_pktdrop_chunk *cp,
  uint32_t *bottle_bw, uint32_t *on_queue)
{
  uint32_t bw_avail;
  unsigned int incr;
  int old_cwnd = net->cwnd;

  /* get bottle neck bw */
  *bottle_bw = ntohl(cp->bottle_bw);
  /* and whats on queue */
  *on_queue = ntohl(cp->current_onq);
  /*
   * adjust the on-queue if our flight is more it could be
   * that the router has not yet gotten data "in-flight" to it
   */
  if (*on_queue < net->flight_size) {
    *on_queue = net->flight_size;
  }
  /* rtt is measured in micro seconds, bottle_bw in bytes per second */
  bw_avail = (uint32_t)(((uint64_t)(*bottle_bw) * net->rtt) / (uint64_t)1000000);
  if (bw_avail > *bottle_bw) {
    /*
     * Cap the growth to no more than the bottle neck.
     * This can happen as RTT slides up due to queues.
     * It also means if you have more than a 1 second
     * RTT with a empty queue you will be limited to the
     * bottle_bw per second no matter if other points
     * have 1/2 the RTT and you could get more out...
     */
    bw_avail = *bottle_bw;
  }
  if (*on_queue > bw_avail) {
    /*
     * No room for anything else don't allow anything
     * else to be "added to the fire".
     */
    int seg_inflight, seg_onqueue, my_portion;

    net->partial_bytes_acked = 0;
    /* how much are we over queue size? */
    incr = *on_queue - bw_avail;
    if (stcb->asoc.seen_a_sack_this_pkt) {
      /*
       * undo any cwnd adjustment that the sack
       * might have made
       */
      net->cwnd = net->prev_cwnd;
    }
    /* Now how much of that is mine? */
    seg_inflight = net->flight_size / net->mtu;
    seg_onqueue = *on_queue / net->mtu;
    my_portion = (incr * seg_inflight) / seg_onqueue;

    /* Have I made an adjustment already */
    if (net->cwnd > net->flight_size) {
      /*
       * for this flight I made an adjustment we
       * need to decrease the portion by a share
       * our previous adjustment.
       */
      int diff_adj;

      diff_adj = net->cwnd - net->flight_size;
      if (diff_adj > my_portion)
        my_portion = 0;
      else
        my_portion -= diff_adj;
    }
    /*
     * back down to the previous cwnd (assume we have
     * had a sack before this packet). minus what ever
     * portion of the overage is my fault.
     */
    net->cwnd -= my_portion;

    /* we will NOT back down more than 1 MTU */
    if (net->cwnd <= net->mtu) {
      net->cwnd = net->mtu;
    }
    /* force into CA */
    net->ssthresh = net->cwnd - 1;
  } else {
    /*
     * Take 1/4 of the space left or max burst up ..
     * whichever is less.
     */
    incr = (bw_avail - *on_queue) >> 2;
    if ((stcb->asoc.max_burst > 0) &&
        (stcb->asoc.max_burst * net->mtu < incr)) {
      incr = stcb->asoc.max_burst * net->mtu;
    }
    net->cwnd += incr;
  }
  if (net->cwnd > bw_avail) {
    /* We can't exceed the pipe size */
    net->cwnd = bw_avail;
  }
  if (net->cwnd < net->mtu) {
    /* We always have 1 MTU */
    net->cwnd = net->mtu;
  }
  sctp_enforce_cwnd_limit(&stcb->asoc, net);
  if (net->cwnd - old_cwnd != 0) {
    /* log only changes */
#if defined(__FreeBSD__) && !defined(__Userspace__)
    SDT_PROBE5(sctp, cwnd, net, pd,
               stcb->asoc.my_vtag,
               ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
               net,
               old_cwnd, net->cwnd);
#endif
    if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
      sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
        SCTP_CWND_LOG_FROM_SAT);
    }
  }
}

static void
sctp_cwnd_update_after_output(struct sctp_tcb *stcb,
                              struct sctp_nets *net, int burst_limit)
{
  int old_cwnd = net->cwnd;

  if (net->ssthresh < net->cwnd)
    net->ssthresh = net->cwnd;
  if (burst_limit) {
    net->cwnd = (net->flight_size + (burst_limit * net->mtu));
    sctp_enforce_cwnd_limit(&stcb->asoc, net);
#if defined(__FreeBSD__) && !defined(__Userspace__)
    SDT_PROBE5(sctp, cwnd, net, bl,
               stcb->asoc.my_vtag,
               ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
               net,
               old_cwnd, net->cwnd);
#endif
    if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
      sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_BRST);
    }
  }
}

static void
sctp_cwnd_update_after_sack(struct sctp_tcb *stcb,
                            struct sctp_association *asoc,
                            int accum_moved, int reneged_all, int will_exit)
{
  /* Passing a zero argument in last disables the rtcc algorithm */
  sctp_cwnd_update_after_sack_common(stcb, asoc, accum_moved, reneged_all, will_exit, 0);
}

static void
sctp_cwnd_update_after_ecn_echo(struct sctp_tcb *stcb, struct sctp_nets *net,
                                int in_window, int num_pkt_lost)
{
  /* Passing a zero argument in last disables the rtcc algorithm */
  sctp_cwnd_update_after_ecn_echo_common(stcb, net, in_window, num_pkt_lost, 0);
}

/* Here starts the RTCCVAR type CC invented by RRS which
 * is a slight mod to RFC2581. We reuse a common routine or
 * two since these algorithms are so close and need to
 * remain the same.
 */
static void
sctp_cwnd_update_rtcc_after_ecn_echo(struct sctp_tcb *stcb, struct sctp_nets *net,
                                     int in_window, int num_pkt_lost)
{
  sctp_cwnd_update_after_ecn_echo_common(stcb, net, in_window, num_pkt_lost, 1);
}

static void sctp_cwnd_update_rtcc_tsn_acknowledged(struct sctp_nets *net,
                                                   struct sctp_tmit_chunk *tp1)
{
  net->cc_mod.rtcc.bw_bytes += tp1->send_size;
}

static void
sctp_cwnd_prepare_rtcc_net_for_sack(struct sctp_tcb *stcb SCTP_UNUSED,
                                    struct sctp_nets *net)
{
  if (net->cc_mod.rtcc.tls_needs_set > 0) {
    /* We had a bw measurement going on */
    struct timeval ltls;
    SCTP_GETPTIME_TIMEVAL(&ltls);
    timevalsub(&ltls, &net->cc_mod.rtcc.tls);
    net->cc_mod.rtcc.new_tot_time = (ltls.tv_sec * 1000000) + ltls.tv_usec;
  }
}

static void
sctp_cwnd_new_rtcc_transmission_begins(struct sctp_tcb *stcb,
                                       struct sctp_nets *net)
{
#if defined(__FreeBSD__) && !defined(__Userspace__)
  uint64_t vtag __dtrace, probepoint __dtrace;

#endif
  if (net->cc_mod.rtcc.lbw) {
#if defined(__FreeBSD__) && !defined(__Userspace__)
    /* Clear the old bw.. we went to 0 in-flight */
    vtag = (net->rtt << 32) | (((uint32_t)(stcb->sctp_ep->sctp_lport)) << 16) |
      (stcb->rport);
    probepoint = (((uint64_t)net->cwnd) << 32);
    /* Probe point 8 */
    probepoint |=  ((8 << 16) | 0);
    SDT_PROBE5(sctp, cwnd, net, rttvar,
               vtag,
               ((net->cc_mod.rtcc.lbw << 32) | 0),
               ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
               net->flight_size,
               probepoint);
#endif
    net->cc_mod.rtcc.lbw_rtt = 0;
    net->cc_mod.rtcc.cwnd_at_bw_set = 0;
    net->cc_mod.rtcc.lbw = 0;
    net->cc_mod.rtcc.bw_bytes_at_last_rttc = 0;
    net->cc_mod.rtcc.vol_reduce = 0;
    net->cc_mod.rtcc.bw_tot_time = 0;
    net->cc_mod.rtcc.bw_bytes = 0;
    net->cc_mod.rtcc.tls_needs_set = 0;
    if (net->cc_mod.rtcc.steady_step) {
      net->cc_mod.rtcc.vol_reduce = 0;
      net->cc_mod.rtcc.step_cnt = 0;
      net->cc_mod.rtcc.last_step_state = 0;
    }
    if (net->cc_mod.rtcc.ret_from_eq) {
      /* less aggressive one - reset cwnd too */
      uint32_t cwnd_in_mtu, cwnd;

      cwnd_in_mtu = SCTP_BASE_SYSCTL(sctp_initial_cwnd);
      if (cwnd_in_mtu == 0) {
        /* Using 0 means that the value of RFC 4960 is used. */
        cwnd = min((net->mtu * 4), max((2 * net->mtu), SCTP_INITIAL_CWND));
      } else {
        /*
         * We take the minimum of the burst limit and the
         * initial congestion window.
         */
        if ((stcb->asoc.max_burst > 0) && (cwnd_in_mtu > stcb->asoc.max_burst))
          cwnd_in_mtu = stcb->asoc.max_burst;
        cwnd = (net->mtu - sizeof(struct sctphdr)) * cwnd_in_mtu;
      }
      if (net->cwnd > cwnd) {
        /* Only set if we are not a timeout (i.e. down to 1 mtu) */
        net->cwnd = cwnd;
      }
    }
  }
}

static void
sctp_set_rtcc_initial_cc_param(struct sctp_tcb *stcb,
                               struct sctp_nets *net)
{
#if defined(__FreeBSD__) && !defined(__Userspace__)
  uint64_t vtag __dtrace, probepoint __dtrace;

#endif
  sctp_set_initial_cc_param(stcb, net);
  stcb->asoc.use_precise_time = 1;
#if defined(__FreeBSD__) && !defined(__Userspace__)
  probepoint = (((uint64_t)net->cwnd) << 32);
  probepoint |=  ((9 << 16) | 0);
  vtag = (net->rtt << 32) |
    (((uint32_t)(stcb->sctp_ep->sctp_lport)) << 16) |
    (stcb->rport);
  SDT_PROBE5(sctp, cwnd, net, rttvar,
             vtag,
             0,
             0,
             0,
             probepoint);
#endif
  net->cc_mod.rtcc.lbw_rtt = 0;
  net->cc_mod.rtcc.cwnd_at_bw_set = 0;
  net->cc_mod.rtcc.vol_reduce = 0;
  net->cc_mod.rtcc.lbw = 0;
  net->cc_mod.rtcc.vol_reduce = 0;
  net->cc_mod.rtcc.bw_bytes_at_last_rttc = 0;
  net->cc_mod.rtcc.bw_tot_time = 0;
  net->cc_mod.rtcc.bw_bytes = 0;
  net->cc_mod.rtcc.tls_needs_set = 0;
  net->cc_mod.rtcc.ret_from_eq = SCTP_BASE_SYSCTL(sctp_rttvar_eqret);
  net->cc_mod.rtcc.steady_step = SCTP_BASE_SYSCTL(sctp_steady_step);
  net->cc_mod.rtcc.use_dccc_ecn = SCTP_BASE_SYSCTL(sctp_use_dccc_ecn);
  net->cc_mod.rtcc.step_cnt = 0;
  net->cc_mod.rtcc.last_step_state = 0;
}

static int
sctp_cwnd_rtcc_socket_option(struct sctp_tcb *stcb, int setorget,
                             struct sctp_cc_option *cc_opt)
{
  struct sctp_nets *net;

  if (setorget == 1) {
    /* a set */
    if (cc_opt->option == SCTP_CC_OPT_RTCC_SETMODE) {
      if ((cc_opt->aid_value.assoc_value != 0) &&
          (cc_opt->aid_value.assoc_value != 1)) {
        return (EINVAL);
      }
      TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
        net->cc_mod.rtcc.ret_from_eq = cc_opt->aid_value.assoc_value;
      }
    } else if (cc_opt->option == SCTP_CC_OPT_USE_DCCC_ECN) {
      if ((cc_opt->aid_value.assoc_value != 0) &&
          (cc_opt->aid_value.assoc_value != 1)) {
        return (EINVAL);
      }
      TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
        net->cc_mod.rtcc.use_dccc_ecn = cc_opt->aid_value.assoc_value;
      }
    } else if (cc_opt->option == SCTP_CC_OPT_STEADY_STEP) {
      TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
        net->cc_mod.rtcc.steady_step = cc_opt->aid_value.assoc_value;
      }
    } else {
      return (EINVAL);
    }
  } else {
    /* a get */
    if (cc_opt->option == SCTP_CC_OPT_RTCC_SETMODE) {
      net = TAILQ_FIRST(&stcb->asoc.nets);
      if (net == NULL) {
        return (EFAULT);
      }
      cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.ret_from_eq;
    } else if (cc_opt->option == SCTP_CC_OPT_USE_DCCC_ECN) {
      net = TAILQ_FIRST(&stcb->asoc.nets);
      if (net == NULL) {
        return (EFAULT);
      }
      cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.use_dccc_ecn;
    } else if (cc_opt->option == SCTP_CC_OPT_STEADY_STEP) {
      net = TAILQ_FIRST(&stcb->asoc.nets);
      if (net == NULL) {
        return (EFAULT);
      }
      cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.steady_step;
    } else {
      return (EINVAL);
    }
  }
  return (0);
}

static void
sctp_cwnd_update_rtcc_packet_transmitted(struct sctp_tcb *stcb SCTP_UNUSED,
                                         struct sctp_nets *net)
{
  if (net->cc_mod.rtcc.tls_needs_set == 0) {
    SCTP_GETPTIME_TIMEVAL(&net->cc_mod.rtcc.tls);
    net->cc_mod.rtcc.tls_needs_set = 2;
  }
}

static void
sctp_cwnd_update_rtcc_after_sack(struct sctp_tcb *stcb,
                                 struct sctp_association *asoc,
                                 int accum_moved, int reneged_all, int will_exit)
{
  /* Passing a one argument at the last enables the rtcc algorithm */
  sctp_cwnd_update_after_sack_common(stcb, asoc, accum_moved, reneged_all, will_exit, 1);
}

static void
sctp_rtt_rtcc_calculated(struct sctp_tcb *stcb SCTP_UNUSED,
                         struct sctp_nets *net,
                         struct timeval *now SCTP_UNUSED)
{
  net->cc_mod.rtcc.rtt_set_this_sack = 1;
}

/* Here starts Sally Floyds HS-TCP */

struct sctp_hs_raise_drop {
  int32_t cwnd;
  int8_t increase;
  int8_t drop_percent;
};

#define SCTP_HS_TABLE_SIZE 73

static const struct sctp_hs_raise_drop sctp_cwnd_adjust[SCTP_HS_TABLE_SIZE] = {
  {38, 1, 50},    /* 0   */
  {118, 2, 44},   /* 1   */
  {221, 3, 41},   /* 2   */
  {347, 4, 38},   /* 3   */
  {495, 5, 37},   /* 4   */
  {663, 6, 35},   /* 5   */
  {851, 7, 34},   /* 6   */
  {1058, 8, 33},    /* 7   */
  {1284, 9, 32},    /* 8   */
  {1529, 10, 31},   /* 9   */
  {1793, 11, 30},   /* 10  */
  {2076, 12, 29},   /* 11  */
  {2378, 13, 28},   /* 12  */
  {2699, 14, 28},   /* 13  */
  {3039, 15, 27},   /* 14  */
  {3399, 16, 27},   /* 15  */
  {3778, 17, 26},   /* 16  */
  {4177, 18, 26},   /* 17  */
  {4596, 19, 25},   /* 18  */
  {5036, 20, 25},   /* 19  */
  {5497, 21, 24},   /* 20  */
  {5979, 22, 24},   /* 21  */
  {6483, 23, 23},   /* 22  */
  {7009, 24, 23},   /* 23  */
  {7558, 25, 22},   /* 24  */
  {8130, 26, 22},   /* 25  */
  {8726, 27, 22},   /* 26  */
  {9346, 28, 21},   /* 27  */
  {9991, 29, 21},   /* 28  */
  {10661, 30, 21},  /* 29  */
  {11358, 31, 20},  /* 30  */
  {12082, 32, 20},  /* 31  */
  {12834, 33, 20},  /* 32  */
  {13614, 34, 19},  /* 33  */
  {14424, 35, 19},  /* 34  */
  {15265, 36, 19},  /* 35  */
  {16137, 37, 19},  /* 36  */
  {17042, 38, 18},  /* 37  */
  {17981, 39, 18},  /* 38  */
  {18955, 40, 18},  /* 39  */
  {19965, 41, 17},  /* 40  */
  {21013, 42, 17},  /* 41  */
  {22101, 43, 17},  /* 42  */
  {23230, 44, 17},  /* 43  */
  {24402, 45, 16},  /* 44  */
  {25618, 46, 16},  /* 45  */
  {26881, 47, 16},  /* 46  */
  {28193, 48, 16},  /* 47  */
  {29557, 49, 15},  /* 48  */
  {30975, 50, 15},  /* 49  */
  {32450, 51, 15},  /* 50  */
  {33986, 52, 15},  /* 51  */
  {35586, 53, 14},  /* 52  */
  {37253, 54, 14},  /* 53  */
  {38992, 55, 14},  /* 54  */
  {40808, 56, 14},  /* 55  */
  {42707, 57, 13},  /* 56  */
  {44694, 58, 13},  /* 57  */
  {46776, 59, 13},  /* 58  */
  {48961, 60, 13},  /* 59  */
  {51258, 61, 13},  /* 60  */
  {53677, 62, 12},  /* 61  */
  {56230, 63, 12},  /* 62  */
  {58932, 64, 12},  /* 63  */
  {61799, 65, 12},  /* 64  */
  {64851, 66, 11},  /* 65  */
  {68113, 67, 11},  /* 66  */
  {71617, 68, 11},  /* 67  */
  {75401, 69, 10},  /* 68  */
  {79517, 70, 10},  /* 69  */
  {84035, 71, 10},  /* 70  */
  {89053, 72, 10},  /* 71  */
  {94717, 73, 9}    /* 72  */
};

static void
sctp_hs_cwnd_increase(struct sctp_tcb *stcb, struct sctp_nets *net)
{
  int cur_val, i, indx, incr;
  int old_cwnd = net->cwnd;

  cur_val = net->cwnd >> 10;
  indx = SCTP_HS_TABLE_SIZE - 1;

  if (cur_val < sctp_cwnd_adjust[0].cwnd) {
    /* normal mode */
    if (net->net_ack > net->mtu) {
      net->cwnd += net->mtu;
    } else {
      net->cwnd += net->net_ack;
    }
  } else {
    for (i = net->last_hs_used; i < SCTP_HS_TABLE_SIZE; i++) {
      if (cur_val < sctp_cwnd_adjust[i].cwnd) {
        indx = i;
        break;
      }
    }
    net->last_hs_used = indx;
    incr = (((int32_t)sctp_cwnd_adjust[indx].increase) << 10);
    net->cwnd += incr;
  }
  sctp_enforce_cwnd_limit(&stcb->asoc, net);
  if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
    sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SS);
  }
}

static void
sctp_hs_cwnd_decrease(struct sctp_tcb *stcb, struct sctp_nets *net)
{
  int cur_val, i, indx;
  int old_cwnd = net->cwnd;

  cur_val = net->cwnd >> 10;
  if (cur_val < sctp_cwnd_adjust[0].cwnd) {
    /* normal mode */
    net->ssthresh = net->cwnd / 2;
    if (net->ssthresh < (net->mtu * 2)) {
      net->ssthresh = 2 * net->mtu;
    }
    net->cwnd = net->ssthresh;
  } else {
    /* drop by the proper amount */
    net->ssthresh = net->cwnd - (int)((net->cwnd / 100) *
        (int32_t)sctp_cwnd_adjust[net->last_hs_used].drop_percent);
    net->cwnd = net->ssthresh;
    /* now where are we */
    indx = net->last_hs_used;
    cur_val = net->cwnd >> 10;
    /* reset where we are in the table */
    if (cur_val < sctp_cwnd_adjust[0].cwnd) {
      /* feel out of hs */
      net->last_hs_used = 0;
    } else {
      for (i = indx; i >= 1; i--) {
        if (cur_val > sctp_cwnd_adjust[i - 1].cwnd) {
          break;
        }
      }
      net->last_hs_used = indx;
    }
  }
  sctp_enforce_cwnd_limit(&stcb->asoc, net);
  if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
    sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_FR);
  }
}

static void
sctp_hs_cwnd_update_after_fr(struct sctp_tcb *stcb,
                             struct sctp_association *asoc)
{
  struct sctp_nets *net;
    /*
   * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off > 0) &&
   * (net->fast_retran_loss_recovery == 0)))
   */
  TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
    if ((asoc->fast_retran_loss_recovery == 0) ||
        (asoc->sctp_cmt_on_off > 0)) {
      /* out of a RFC2582 Fast recovery window? */
      if (net->net_ack > 0) {
        /*
         * per section 7.2.3, are there any
         * destinations that had a fast retransmit
         * to them. If so what we need to do is
         * adjust ssthresh and cwnd.
         */
        struct sctp_tmit_chunk *lchk;

        sctp_hs_cwnd_decrease(stcb, net);

        lchk = TAILQ_FIRST(&asoc->send_queue);

        net->partial_bytes_acked = 0;
        /* Turn on fast recovery window */
        asoc->fast_retran_loss_recovery = 1;
        if (lchk == NULL) {
          /* Mark end of the window */
          asoc->fast_recovery_tsn = asoc->sending_seq - 1;
        } else {
          asoc->fast_recovery_tsn = lchk->rec.data.tsn - 1;
        }

        /*
         * CMT fast recovery -- per destination
         * recovery variable.
         */
        net->fast_retran_loss_recovery = 1;

        if (lchk == NULL) {
          /* Mark end of the window */
          net->fast_recovery_tsn = asoc->sending_seq - 1;
        } else {
          net->fast_recovery_tsn = lchk->rec.data.tsn - 1;
        }

        sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
            stcb->sctp_ep, stcb, net,
                        SCTP_FROM_SCTP_CC_FUNCTIONS + SCTP_LOC_2);
        sctp_timer_start(SCTP_TIMER_TYPE_SEND,
             stcb->sctp_ep, stcb, net);
      }
    } else if (net->net_ack > 0) {
      /*
       * Mark a peg that we WOULD have done a cwnd
       * reduction but RFC2582 prevented this action.
       */
      SCTP_STAT_INCR(sctps_fastretransinrtt);
    }
  }
}

static void
sctp_hs_cwnd_update_after_sack(struct sctp_tcb *stcb,
                               struct sctp_association *asoc,
                               int accum_moved, int reneged_all SCTP_UNUSED, int will_exit)
{
  struct sctp_nets *net;
  /******************************/
  /* update cwnd and Early FR   */
  /******************************/
  TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
#ifdef JANA_CMT_FAST_RECOVERY
    /*
     * CMT fast recovery code. Need to debug.
     */
    if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
      if (SCTP_TSN_GE(asoc->last_acked_seq, net->fast_recovery_tsn) ||
          SCTP_TSN_GE(net->pseudo_cumack,net->fast_recovery_tsn)) {
        net->will_exit_fast_recovery = 1;
      }
    }
#endif
    /* if nothing was acked on this destination skip it */
    if (net->net_ack == 0) {
      if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
        sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
      }
      continue;
    }
#ifdef JANA_CMT_FAST_RECOVERY
    /* CMT fast recovery code
     */
    /*
    if (sctp_cmt_on_off > 0 && net->fast_retran_loss_recovery && net->will_exit_fast_recovery == 0) {
        @@@ Do something
     }
     else if (sctp_cmt_on_off == 0 && asoc->fast_retran_loss_recovery && will_exit == 0) {
    */
#endif

     if (asoc->fast_retran_loss_recovery &&
         (will_exit == 0) &&
         (asoc->sctp_cmt_on_off == 0)) {
      /*
       * If we are in loss recovery we skip any cwnd
       * update
       */
      return;
    }
    /*
     * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
     * moved.
     */
    if (accum_moved ||
        ((asoc->sctp_cmt_on_off > 0) && net->new_pseudo_cumack)) {
      /* If the cumulative ack moved we can proceed */
      if (net->cwnd <= net->ssthresh) {
        /* We are in slow start */
        if (net->flight_size + net->net_ack >= net->cwnd) {
          sctp_hs_cwnd_increase(stcb, net);
        } else {
          if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
            sctp_log_cwnd(stcb, net, net->net_ack,
              SCTP_CWND_LOG_NOADV_SS);
          }
        }
      } else {
        /* We are in congestion avoidance */
        net->partial_bytes_acked += net->net_ack;
        if ((net->flight_size + net->net_ack >= net->cwnd) &&
            (net->partial_bytes_acked >= net->cwnd)) {
          net->partial_bytes_acked -= net->cwnd;
          net->cwnd += net->mtu;
          sctp_enforce_cwnd_limit(asoc, net);
          if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
            sctp_log_cwnd(stcb, net, net->mtu,
              SCTP_CWND_LOG_FROM_CA);
          }
        } else {
          if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
            sctp_log_cwnd(stcb, net, net->net_ack,
              SCTP_CWND_LOG_NOADV_CA);
          }
        }
      }
    } else {
      if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
        sctp_log_cwnd(stcb, net, net->mtu,
          SCTP_CWND_LOG_NO_CUMACK);
      }
    }
  }
}

/*
 * H-TCP congestion control. The algorithm is detailed in:
 * R.N.Shorten, D.J.Leith:
 *   "H-TCP: TCP for high-speed and long-distance networks"
 *   Proc. PFLDnet, Argonne, 2004.
 * http://www.hamilton.ie/net/htcp3.pdf
 */

static int use_rtt_scaling = 1;
static int use_bandwidth_switch = 1;

static inline int
between(uint32_t seq1, uint32_t seq2, uint32_t seq3)
{
  return (seq3 - seq2 >= seq1 - seq2);
}

static inline uint32_t
htcp_cong_time(struct htcp *ca)
{
  return (sctp_get_tick_count() - ca->last_cong);
}

static inline uint32_t
htcp_ccount(struct htcp *ca)
{
  return (ca->minRTT == 0 ? htcp_cong_time(ca) : htcp_cong_time(ca)/ca->minRTT);
}

static inline void
htcp_reset(struct htcp *ca)
{
  ca->undo_last_cong = ca->last_cong;
  ca->undo_maxRTT = ca->maxRTT;
  ca->undo_old_maxB = ca->old_maxB;
  ca->last_cong = sctp_get_tick_count();
}

#ifdef SCTP_NOT_USED

static uint32_t
htcp_cwnd_undo(struct sctp_tcb *stcb, struct sctp_nets *net)
{
  net->cc_mod.htcp_ca.last_cong = net->cc_mod.htcp_ca.undo_last_cong;
  net->cc_mod.htcp_ca.maxRTT = net->cc_mod.htcp_ca.undo_maxRTT;
  net->cc_mod.htcp_ca.old_maxB = net->cc_mod.htcp_ca.undo_old_maxB;
  return (max(net->cwnd, ((net->ssthresh/net->mtu<<7)/net->cc_mod.htcp_ca.beta)*net->mtu));
}

#endif

static inline void
measure_rtt(struct sctp_nets *net)
{
  uint32_t srtt = net->lastsa>>SCTP_RTT_SHIFT;

  /* keep track of minimum RTT seen so far, minRTT is zero at first */
  if (net->cc_mod.htcp_ca.minRTT > srtt || !net->cc_mod.htcp_ca.minRTT)
    net->cc_mod.htcp_ca.minRTT = srtt;

  /* max RTT */
  if (net->fast_retran_ip == 0 && net->ssthresh < 0xFFFF && htcp_ccount(&net->cc_mod.htcp_ca) > 3) {
    if (net->cc_mod.htcp_ca.maxRTT < net->cc_mod.htcp_ca.minRTT)
      net->cc_mod.htcp_ca.maxRTT = net->cc_mod.htcp_ca.minRTT;
    if (net->cc_mod.htcp_ca.maxRTT < srtt && srtt <= net->cc_mod.htcp_ca.maxRTT+sctp_msecs_to_ticks(20))
      net->cc_mod.htcp_ca.maxRTT = srtt;
  }
}

static void
measure_achieved_throughput(struct sctp_nets *net)
{
  uint32_t now = sctp_get_tick_count();

  if (net->fast_retran_ip == 0)
    net->cc_mod.htcp_ca.bytes_acked = net->net_ack;

  if (!use_bandwidth_switch)
    return;

  /* achieved throughput calculations */
  /* JRS - not 100% sure of this statement */
  if (net->fast_retran_ip == 1) {
    net->cc_mod.htcp_ca.bytecount = 0;
    net->cc_mod.htcp_ca.lasttime = now;
    return;
  }

  net->cc_mod.htcp_ca.bytecount += net->net_ack;
  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)) &&
      (now - net->cc_mod.htcp_ca.lasttime >= net->cc_mod.htcp_ca.minRTT) &&
      (net->cc_mod.htcp_ca.minRTT > 0)) {
    uint32_t cur_Bi = net->cc_mod.htcp_ca.bytecount/net->mtu*hz/(now - net->cc_mod.htcp_ca.lasttime);

    if (htcp_ccount(&net->cc_mod.htcp_ca) <= 3) {
      /* just after backoff */
      net->cc_mod.htcp_ca.minB = net->cc_mod.htcp_ca.maxB = net->cc_mod.htcp_ca.Bi = cur_Bi;
    } else {
      net->cc_mod.htcp_ca.Bi = (3*net->cc_mod.htcp_ca.Bi + cur_Bi)/4;
      if (net->cc_mod.htcp_ca.Bi > net->cc_mod.htcp_ca.maxB)
        net->cc_mod.htcp_ca.maxB = net->cc_mod.htcp_ca.Bi;
      if (net->cc_mod.htcp_ca.minB > net->cc_mod.htcp_ca.maxB)
        net->cc_mod.htcp_ca.minB = net->cc_mod.htcp_ca.maxB;
    }
    net->cc_mod.htcp_ca.bytecount = 0;
    net->cc_mod.htcp_ca.lasttime = now;
  }
}

static inline void
htcp_beta_update(struct htcp *ca, uint32_t minRTT, uint32_t maxRTT)
{
  if (use_bandwidth_switch) {
    uint32_t maxB = ca->maxB;
    uint32_t old_maxB = ca->old_maxB;
    ca->old_maxB = ca->maxB;

    if (!between(5*maxB, 4*old_maxB, 6*old_maxB)) {
      ca->beta = BETA_MIN;
      ca->modeswitch = 0;
      return;
    }
  }

  if (ca->modeswitch && minRTT > sctp_msecs_to_ticks(10) && maxRTT) {
    ca->beta = (minRTT<<7)/maxRTT;
    if (ca->beta < BETA_MIN)
      ca->beta = BETA_MIN;
    else if (ca->beta > BETA_MAX)
      ca->beta = BETA_MAX;
  } else {
    ca->beta = BETA_MIN;
    ca->modeswitch = 1;
  }
}

static inline void
htcp_alpha_update(struct htcp *ca)
{
  uint32_t minRTT = ca->minRTT;
  uint32_t factor = 1;
  uint32_t diff = htcp_cong_time(ca);

  if (diff > (uint32_t)hz) {
    diff -= hz;
    factor = 1+ (10 * diff + ((diff / 2) * (diff / 2) / hz)) / hz;
  }

  if (use_rtt_scaling && minRTT) {
    uint32_t scale = (hz << 3) / (10 * minRTT);
    scale = min(max(scale, 1U << 2), 10U << 3); /* clamping ratio to interval [0.5,10]<<3 */
    factor = (factor << 3) / scale;
    if (factor != 0)
      factor = 1;
  }

  ca->alpha = 2 * factor * ((1 << 7) - ca->beta);
  if (ca->alpha != 0)
    ca->alpha = ALPHA_BASE;
}

/* After we have the rtt data to calculate beta, we'd still prefer to wait one
 * rtt before we adjust our beta to ensure we are working from a consistent
 * data.
 *
 * This function should be called when we hit a congestion event since only at
 * that point do we really have a real sense of maxRTT (the queues en route
 * were getting just too full now).
 */
static void
htcp_param_update(struct sctp_nets *net)
{
  uint32_t minRTT = net->cc_mod.htcp_ca.minRTT;
  uint32_t maxRTT = net->cc_mod.htcp_ca.maxRTT;

  htcp_beta_update(&net->cc_mod.htcp_ca, minRTT, maxRTT);
  htcp_alpha_update(&net->cc_mod.htcp_ca);

  /* add slowly fading memory for maxRTT to accommodate routing changes etc */
  if (minRTT > 0 && maxRTT > minRTT)
    net->cc_mod.htcp_ca.maxRTT = minRTT + ((maxRTT-minRTT)*95)/100;
}

static uint32_t
htcp_recalc_ssthresh(struct sctp_nets *net)
{
  htcp_param_update(net);
  return (max(((net->cwnd/net->mtu * net->cc_mod.htcp_ca.beta) >> 7)*net->mtu, 2U*net->mtu));
}

static void
htcp_cong_avoid(struct sctp_tcb *stcb, struct sctp_nets *net)
{
  /*-
   * How to handle these functions?
   *  if (!tcp_is_cwnd_limited(sk, in_flight)) RRS - good question.
   *    return;
   */
  if (net->cwnd <= net->ssthresh) {
    /* We are in slow start */
    if (net->flight_size + net->net_ack >= net->cwnd) {
      if (net->net_ack > (net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable))) {
        net->cwnd += (net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable));
        if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
          sctp_log_cwnd(stcb, net, net->mtu,
            SCTP_CWND_LOG_FROM_SS);
        }

      } else {
        net->cwnd += net->net_ack;
        if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
          sctp_log_cwnd(stcb, net, net->net_ack,
            SCTP_CWND_LOG_FROM_SS);
        }
      }
      sctp_enforce_cwnd_limit(&stcb->asoc, net);
    } else {
      if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
        sctp_log_cwnd(stcb, net, net->net_ack,
          SCTP_CWND_LOG_NOADV_SS);
      }
    }
  } else {
    measure_rtt(net);

    /* In dangerous area, increase slowly.
     * In theory this is net->cwnd += alpha / net->cwnd
     */
    /* What is snd_cwnd_cnt?? */
    if (((net->partial_bytes_acked/net->mtu * net->cc_mod.htcp_ca.alpha) >> 7)*net->mtu >= net->cwnd) {
      /*-
       * Does SCTP have a cwnd clamp?
       * if (net->snd_cwnd < net->snd_cwnd_clamp) - Nope (RRS).
       */
      net->cwnd += net->mtu;
      net->partial_bytes_acked = 0;
      sctp_enforce_cwnd_limit(&stcb->asoc, net);
      htcp_alpha_update(&net->cc_mod.htcp_ca);
      if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
        sctp_log_cwnd(stcb, net, net->mtu,
          SCTP_CWND_LOG_FROM_CA);
      }
    } else {
      net->partial_bytes_acked += net->net_ack;
      if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
        sctp_log_cwnd(stcb, net, net->net_ack,
          SCTP_CWND_LOG_NOADV_CA);
      }
    }

    net->cc_mod.htcp_ca.bytes_acked = net->mtu;
  }
}

#ifdef SCTP_NOT_USED
/* Lower bound on congestion window. */
static uint32_t
htcp_min_cwnd(struct sctp_tcb *stcb, struct sctp_nets *net)
{
  return (net->ssthresh);
}
#endif

static void
htcp_init(struct sctp_nets *net)
{
  memset(&net->cc_mod.htcp_ca, 0, sizeof(struct htcp));
  net->cc_mod.htcp_ca.alpha = ALPHA_BASE;
  net->cc_mod.htcp_ca.beta = BETA_MIN;
  net->cc_mod.htcp_ca.bytes_acked = net->mtu;
  net->cc_mod.htcp_ca.last_cong = sctp_get_tick_count();
}

static void
sctp_htcp_set_initial_cc_param(struct sctp_tcb *stcb, struct sctp_nets *net)
{
  /*
   * We take the max of the burst limit times a MTU or the
   * INITIAL_CWND. We then limit this to 4 MTU's of sending.
   */
  net->cwnd = min((net->mtu * 4), max((2 * net->mtu), SCTP_INITIAL_CWND));
  net->ssthresh = stcb->asoc.peers_rwnd;
  sctp_enforce_cwnd_limit(&stcb->asoc, net);
  htcp_init(net);

  if (SCTP_BASE_SYSCTL(sctp_logging_level) & (SCTP_CWND_MONITOR_ENABLE|SCTP_CWND_LOGGING_ENABLE)) {
    sctp_log_cwnd(stcb, net, 0, SCTP_CWND_INITIALIZATION);
  }
}

static void
sctp_htcp_cwnd_update_after_sack(struct sctp_tcb *stcb,
     struct sctp_association *asoc,
     int accum_moved, int reneged_all SCTP_UNUSED, int will_exit)
{
  struct sctp_nets *net;

  /******************************/
  /* update cwnd and Early FR   */
  /******************************/
  TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
#ifdef JANA_CMT_FAST_RECOVERY
    /*
     * CMT fast recovery code. Need to debug.
     */
    if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
      if (SCTP_TSN_GE(asoc->last_acked_seq, net->fast_recovery_tsn) ||
          SCTP_TSN_GE(net->pseudo_cumack,net->fast_recovery_tsn)) {
        net->will_exit_fast_recovery = 1;
      }
    }
#endif
    /* if nothing was acked on this destination skip it */
    if (net->net_ack == 0) {
      if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
        sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
      }
      continue;
    }
#ifdef JANA_CMT_FAST_RECOVERY
    /* CMT fast recovery code
     */
    /*
    if (sctp_cmt_on_off > 0 && net->fast_retran_loss_recovery && net->will_exit_fast_recovery == 0) {
        @@@ Do something
     }
     else if (sctp_cmt_on_off == 0 && asoc->fast_retran_loss_recovery && will_exit == 0) {
    */
#endif

    if (asoc->fast_retran_loss_recovery &&
        will_exit == 0 &&
        (asoc->sctp_cmt_on_off == 0)) {
      /*
       * If we are in loss recovery we skip any cwnd
       * update
       */
      return;
    }
    /*
     * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
     * moved.
     */
    if (accum_moved ||
        ((asoc->sctp_cmt_on_off > 0) && net->new_pseudo_cumack)) {
      htcp_cong_avoid(stcb, net);
      measure_achieved_throughput(net);
    } else {
      if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
        sctp_log_cwnd(stcb, net, net->mtu,
          SCTP_CWND_LOG_NO_CUMACK);
      }
    }
  }
}

static void
sctp_htcp_cwnd_update_after_fr(struct sctp_tcb *stcb,
    struct sctp_association *asoc)
{
  struct sctp_nets *net;
  /*
   * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off > 0) &&
   * (net->fast_retran_loss_recovery == 0)))
   */
  TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
    if ((asoc->fast_retran_loss_recovery == 0) ||
        (asoc->sctp_cmt_on_off > 0)) {
      /* out of a RFC2582 Fast recovery window? */
      if (net->net_ack > 0) {
        /*
         * per section 7.2.3, are there any
         * destinations that had a fast retransmit
         * to them. If so what we need to do is
         * adjust ssthresh and cwnd.
         */
        struct sctp_tmit_chunk *lchk;
        int old_cwnd = net->cwnd;

        /* JRS - reset as if state were changed */
        htcp_reset(&net->cc_mod.htcp_ca);
        net->ssthresh = htcp_recalc_ssthresh(net);
        net->cwnd = net->ssthresh;
        sctp_enforce_cwnd_limit(asoc, net);
        if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
          sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
            SCTP_CWND_LOG_FROM_FR);
        }
        lchk = TAILQ_FIRST(&asoc->send_queue);

        net->partial_bytes_acked = 0;
        /* Turn on fast recovery window */
        asoc->fast_retran_loss_recovery = 1;
        if (lchk == NULL) {
          /* Mark end of the window */
          asoc->fast_recovery_tsn = asoc->sending_seq - 1;
        } else {
          asoc->fast_recovery_tsn = lchk->rec.data.tsn - 1;
        }

        /*
         * CMT fast recovery -- per destination
         * recovery variable.
         */
        net->fast_retran_loss_recovery = 1;

        if (lchk == NULL) {
          /* Mark end of the window */
          net->fast_recovery_tsn = asoc->sending_seq - 1;
        } else {
          net->fast_recovery_tsn = lchk->rec.data.tsn - 1;
        }

        sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
            stcb->sctp_ep, stcb, net,
                        SCTP_FROM_SCTP_CC_FUNCTIONS + SCTP_LOC_3);
        sctp_timer_start(SCTP_TIMER_TYPE_SEND,
             stcb->sctp_ep, stcb, net);
      }
    } else if (net->net_ack > 0) {
      /*
       * Mark a peg that we WOULD have done a cwnd
       * reduction but RFC2582 prevented this action.
       */
      SCTP_STAT_INCR(sctps_fastretransinrtt);
    }
  }
}

static void
sctp_htcp_cwnd_update_after_timeout(struct sctp_tcb *stcb,
  struct sctp_nets *net)
{
    int old_cwnd = net->cwnd;

    /* JRS - reset as if the state were being changed to timeout */
    htcp_reset(&net->cc_mod.htcp_ca);
    net->ssthresh = htcp_recalc_ssthresh(net);
    net->cwnd = net->mtu;
    net->partial_bytes_acked = 0;
    if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
      sctp_log_cwnd(stcb, net, net->cwnd - old_cwnd, SCTP_CWND_LOG_FROM_RTX);
    }
}

static void
sctp_htcp_cwnd_update_after_ecn_echo(struct sctp_tcb *stcb,
    struct sctp_nets *net, int in_window, int num_pkt_lost SCTP_UNUSED)
{
  int old_cwnd;
  old_cwnd = net->cwnd;

  /* JRS - reset hctp as if state changed */
  if (in_window == 0) {
    htcp_reset(&net->cc_mod.htcp_ca);
    SCTP_STAT_INCR(sctps_ecnereducedcwnd);
    net->ssthresh = htcp_recalc_ssthresh(net);
    if (net->ssthresh < net->mtu) {
      net->ssthresh = net->mtu;
      /* here back off the timer as well, to slow us down */
      net->RTO <<= 1;
    }
    net->cwnd = net->ssthresh;
    sctp_enforce_cwnd_limit(&stcb->asoc, net);
    if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
      sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
    }
  }
}

const struct sctp_cc_functions sctp_cc_functions[] = {
{
#if defined(_WIN32) && !defined(__MINGW32__)
  sctp_set_initial_cc_param,
  sctp_cwnd_update_after_sack,
  sctp_cwnd_update_exit_pf_common,
  sctp_cwnd_update_after_fr,
  sctp_cwnd_update_after_timeout,
  sctp_cwnd_update_after_ecn_echo,
  sctp_cwnd_update_after_packet_dropped,
  sctp_cwnd_update_after_output,
#else
  .sctp_set_initial_cc_param = sctp_set_initial_cc_param,
  .sctp_cwnd_update_after_sack = sctp_cwnd_update_after_sack,
  .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
  .sctp_cwnd_update_after_fr = sctp_cwnd_update_after_fr,
  .sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
  .sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_after_ecn_echo,
  .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
  .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
#endif
},
{
#if defined(_WIN32) && !defined(__MINGW32__)
  sctp_set_initial_cc_param,
  sctp_hs_cwnd_update_after_sack,
  sctp_cwnd_update_exit_pf_common,
  sctp_hs_cwnd_update_after_fr,
  sctp_cwnd_update_after_timeout,
  sctp_cwnd_update_after_ecn_echo,
  sctp_cwnd_update_after_packet_dropped,
  sctp_cwnd_update_after_output,
#else
  .sctp_set_initial_cc_param = sctp_set_initial_cc_param,
  .sctp_cwnd_update_after_sack = sctp_hs_cwnd_update_after_sack,
  .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
  .sctp_cwnd_update_after_fr = sctp_hs_cwnd_update_after_fr,
  .sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
  .sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_after_ecn_echo,
  .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
  .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
#endif
},
{
#if defined(_WIN32) && !defined(__MINGW32__)
  sctp_htcp_set_initial_cc_param,
  sctp_htcp_cwnd_update_after_sack,
  sctp_cwnd_update_exit_pf_common,
  sctp_htcp_cwnd_update_after_fr,
  sctp_htcp_cwnd_update_after_timeout,
  sctp_htcp_cwnd_update_after_ecn_echo,
  sctp_cwnd_update_after_packet_dropped,
  sctp_cwnd_update_after_output,
#else
  .sctp_set_initial_cc_param = sctp_htcp_set_initial_cc_param,
  .sctp_cwnd_update_after_sack = sctp_htcp_cwnd_update_after_sack,
  .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
  .sctp_cwnd_update_after_fr = sctp_htcp_cwnd_update_after_fr,
  .sctp_cwnd_update_after_timeout = sctp_htcp_cwnd_update_after_timeout,
  .sctp_cwnd_update_after_ecn_echo = sctp_htcp_cwnd_update_after_ecn_echo,
  .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
  .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
#endif
},
{
#if defined(_WIN32) && !defined(__MINGW32__)
  sctp_set_rtcc_initial_cc_param,
  sctp_cwnd_update_rtcc_after_sack,
  sctp_cwnd_update_exit_pf_common,
  sctp_cwnd_update_after_fr,
  sctp_cwnd_update_after_timeout,
  sctp_cwnd_update_rtcc_after_ecn_echo,
  sctp_cwnd_update_after_packet_dropped,
  sctp_cwnd_update_after_output,
  sctp_cwnd_update_rtcc_packet_transmitted,
  sctp_cwnd_update_rtcc_tsn_acknowledged,
  sctp_cwnd_new_rtcc_transmission_begins,
  sctp_cwnd_prepare_rtcc_net_for_sack,
  sctp_cwnd_rtcc_socket_option,
  sctp_rtt_rtcc_calculated
#else
  .sctp_set_initial_cc_param = sctp_set_rtcc_initial_cc_param,
  .sctp_cwnd_update_after_sack = sctp_cwnd_update_rtcc_after_sack,
  .sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
  .sctp_cwnd_update_after_fr = sctp_cwnd_update_after_fr,
  .sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
  .sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_rtcc_after_ecn_echo,
  .sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
  .sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
  .sctp_cwnd_update_packet_transmitted = sctp_cwnd_update_rtcc_packet_transmitted,
  .sctp_cwnd_update_tsn_acknowledged = sctp_cwnd_update_rtcc_tsn_acknowledged,
  .sctp_cwnd_new_transmission_begins = sctp_cwnd_new_rtcc_transmission_begins,
  .sctp_cwnd_prepare_net_for_sack = sctp_cwnd_prepare_rtcc_net_for_sack,
  .sctp_cwnd_socket_option = sctp_cwnd_rtcc_socket_option,
  .sctp_rtt_calculated = sctp_rtt_rtcc_calculated
#endif
}
};

Coverage Report

Created: 2026-07-15 06:30