/*-
 * 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>
#include <netinet/sctp_kdtrace.h>

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

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;
        SDT_PROBE5(sctp, cwnd, net, init,
            stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
            0, net->cwnd);
        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);
                                SDT_PROBE5(sctp, cwnd, net, fr,
                                    stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
                                    old_cwnd, net->cwnd);
                                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 */

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)
{
        uint64_t oth __sdt_used, probepoint __sdt_used;

        probepoint = (((uint64_t)net->cwnd) << 32);
        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.
                 */
                /* 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);
                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 */
                                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);
                                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.
                 */
                /* 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);
                if (net->cc_mod.rtcc.steady_step) {
                        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);
                        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
         */
        /* 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);
        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);
}

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)
{
        uint64_t oth __sdt_used, probepoint __sdt_used;

        /* Bandwidth decreased. */
        probepoint = (((uint64_t)net->cwnd) << 32);
        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? */
                        /* 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);
                        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);
                }
                /* 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);
                /* Someone else - fight for more? */
                if (net->cc_mod.rtcc.steady_step) {
                        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);
                        /*
                         * 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 */
                /* 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);
                if (net->cc_mod.rtcc.steady_step) {
                        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);
                        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 */
        /* 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);
        if (net->cc_mod.rtcc.steady_step) {
                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);
                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);
        }
}

static int
cc_bw_increase(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw, uint64_t vtag)
{
        uint64_t oth __sdt_used, probepoint __sdt_used;

        /*
         * 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.
         */
        /* 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);
        if (net->cc_mod.rtcc.steady_step) {
                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);
                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;
        uint64_t probepoint __sdt_used, rtt, vtag;
        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);
        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;
        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;
                                probepoint |= ((0xb << 16) | inst_ind);
                        } else {
                                inst_ind = net->cc_mod.rtcc.last_inst_ind;
                                inst_bw = bytes_for_this_rtt / (uint64_t)(net->rtt);
                                /* Can't determine do not change */
                                probepoint |= ((0xc << 16) | inst_ind);
                        }
                } else {
                        inst_ind = net->cc_mod.rtcc.last_inst_ind;
                        inst_bw = bytes_for_this_rtt;
                        /* Can't determine do not change */
                        probepoint |= ((0xd << 16) | inst_ind);
                }
                SDT_PROBE5(sctp, cwnd, net, rttvar,
                    vtag,
                    ((nbw << 32) | inst_bw),
                    ((net->cc_mod.rtcc.lbw_rtt << 32) | rtt),
                    net->flight_size,
                    probepoint);
        } 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) {
                ret = cc_bw_increase(stcb, net, nbw, vtag);
                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) {
                ret = cc_bw_decrease(stcb, net, nbw, rtt_offset, vtag, inst_ind);
                goto out;
        }
        /*
         * If we reach here then we are in a situation where the bw stayed
         * the same.
         */
        ret = cc_bw_same(stcb, net, nbw, rtt_offset, vtag, inst_ind);
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;
        int old_cwnd __sdt_used;
        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 {
                                uint64_t vtag __sdt_used, probepoint __sdt_used;

                                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);
                                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;

                                        old_cwnd = net->cwnd;
                                        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);
                                        }
                                        SDT_PROBE5(sctp, cwnd, net, ack,
                                            stcb->asoc.my_vtag,
                                            ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
                                            net,
                                            old_cwnd, net->cwnd);
                                } 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;
                                        old_cwnd = net->cwnd;
                                        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);
                                        SDT_PROBE5(sctp, cwnd, net, ack,
                                            stcb->asoc.my_vtag,
                                            ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
                                            net,
                                            old_cwnd, net->cwnd);
                                        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);
                        }
                }
        }
}

static void
sctp_cwnd_update_exit_pf_common(struct sctp_tcb *stcb, struct sctp_nets *net)
{
        int old_cwnd __sdt_used;

        old_cwnd = net->cwnd;
        net->cwnd = net->mtu;
        SDT_PROBE5(sctp, cwnd, net, ack,
            stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
            old_cwnd, net->cwnd);
        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;
        SDT_PROBE5(sctp, cwnd, net, to,
            stcb->asoc.my_vtag,
            ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
            net,
            old_cwnd, net->cwnd);
        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;
                        SDT_PROBE5(sctp, cwnd, net, ecn,
                            stcb->asoc.my_vtag,
                            ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
                            net,
                            old_cwnd, net->cwnd);
                        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 */
                SDT_PROBE5(sctp, cwnd, net, pd,
                    stcb->asoc.my_vtag,
                    ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
                    net,
                    old_cwnd, net->cwnd);
                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);
                SDT_PROBE5(sctp, cwnd, net, bl,
                    stcb->asoc.my_vtag,
                    ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
                    net,
                    old_cwnd, net->cwnd);
                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)
{
        uint64_t vtag __sdt_used, probepoint __sdt_used;

        if (net->cc_mod.rtcc.lbw) {
                /* 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);
                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)
{
        uint64_t vtag __sdt_used, probepoint __sdt_used;

        sctp_set_initial_cc_param(stcb, net);
        stcb->asoc.use_precise_time = 1;
        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);
        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[] = {
        {
                .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,
        },
        {
                .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,
        },
        {
                .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,
        },
        {
                .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
        }
};