text: /*-
   * 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.
   */
  
  #ifdef __FreeBSD__
  #include <sys/cdefs.h>
  __FBSDID("$FreeBSD: head/sys/netinet/sctp_cc_functions.c 279859 2015-03-10 19:49:25Z tuexen $");
  #endif
  
  #include <netinet/sctp_os.h>
  #include <netinet/sctp_var.h>
  #include <netinet/sctp_sysctl.h>
  #include <netinet/sctp_pcb.h>
  #include <netinet/sctp_header.h>
  #include <netinet/sctputil.h>
  #include <netinet/sctp_output.h>
  #include <netinet/sctp_input.h>
  #include <netinet/sctp_indata.h>
  #include <netinet/sctp_uio.h>
  #include <netinet/sctp_timer.h>
  #include <netinet/sctp_auth.h>
  #include <netinet/sctp_asconf.h>
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  #include <netinet/sctp_dtrace_declare.h>
  #endif
  
  #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;
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	SDT_PROBE(sctp, cwnd, net, init,
  	          stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
  	          0, net->cwnd);
  #endif
  	if (SCTP_BASE_SYSCTL(sctp_logging_level) &
  	    (SCTP_CWND_MONITOR_ENABLE|SCTP_CWND_LOGGING_ENABLE)) {
  		sctp_log_cwnd(stcb, net, 0, SCTP_CWND_INITIALIZATION);
  	}
  }
  
  static void
  sctp_cwnd_update_after_fr(struct sctp_tcb *stcb,
                            struct sctp_association *asoc)
  {
  	struct sctp_nets *net;
  	uint32_t t_ssthresh, t_cwnd;
  	uint64_t t_ucwnd_sbw;
  
  	/* MT FIXME: Don't compute this over and over again */
  	t_ssthresh = 0;
  	t_cwnd = 0;
  	t_ucwnd_sbw = 0;
  	if ((asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) ||
  	    (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2)) {
  		TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
  			t_ssthresh += net->ssthresh;
  			t_cwnd += net->cwnd;
  			if (net->lastsa > 0) {
  				t_ucwnd_sbw += (uint64_t)net->cwnd / (uint64_t)net->lastsa;
  			}
  		}
  		if (t_ucwnd_sbw == 0) {
  			t_ucwnd_sbw = 1;
  		}
  	}
  
  	/*-
  	 * CMT fast recovery code. Need to debug. ((sctp_cmt_on_off > 0) &&
  	 * (net->fast_retran_loss_recovery == 0)))
  	 */
  	TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
  		if ((asoc->fast_retran_loss_recovery == 0) ||
  		    (asoc->sctp_cmt_on_off > 0)) {
  			/* out of a RFC2582 Fast recovery window? */
  			if (net->net_ack > 0) {
  				/*
  				 * per section 7.2.3, are there any
  				 * destinations that had a fast retransmit
  				 * to them. If so what we need to do is
  				 * adjust ssthresh and cwnd.
  				 */
  				struct sctp_tmit_chunk *lchk;
  				int old_cwnd = net->cwnd;
  
  				if ((asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) ||
  				    (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2)) {
  					if (asoc->sctp_cmt_on_off == SCTP_CMT_RPV1) {
  						net->ssthresh = (uint32_t)(((uint64_t)4 *
  					                                    (uint64_t)net->mtu *
  					                                    (uint64_t)net->ssthresh) /
  						                           (uint64_t)t_ssthresh);
  
  					}
  					if (asoc->sctp_cmt_on_off == SCTP_CMT_RPV2) {
  						uint32_t srtt;
  
  						srtt = net->lastsa;
  						/* lastsa>>3;  we don't need to devide ...*/
  						if (srtt == 0) {
  							srtt = 1;
  						}
  						/* Short Version => Equal to Contel Version MBe */
  						net->ssthresh = (uint32_t) (((uint64_t)4 *
  						                             (uint64_t)net->mtu *
  						                             (uint64_t)net->cwnd) /
  						                            ((uint64_t)srtt *
  						                             t_ucwnd_sbw));
  									     /* INCREASE FACTOR */;
  					}
  					if ((net->cwnd > t_cwnd / 2) &&
  					    (net->ssthresh < net->cwnd - t_cwnd / 2)) {
  						net->ssthresh = net->cwnd - t_cwnd / 2;
  					}
  					if (net->ssthresh < net->mtu) {
  						net->ssthresh = net->mtu;
  					}
  				} else {
  					net->ssthresh = net->cwnd / 2;
  					if (net->ssthresh < (net->mtu * 2)) {
  						net->ssthresh = 2 * net->mtu;
  					}
  				}
  				net->cwnd = net->ssthresh;
  				sctp_enforce_cwnd_limit(asoc, net);
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  				SDT_PROBE(sctp, cwnd, net, fr,
  					  stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
  					  old_cwnd, net->cwnd);
  #endif
  				if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
  					sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
  						SCTP_CWND_LOG_FROM_FR);
  				}
  				lchk = TAILQ_FIRST(&asoc->send_queue);
  
  				net->partial_bytes_acked = 0;
  				/* Turn on fast recovery window */
  				asoc->fast_retran_loss_recovery = 1;
  				if (lchk == NULL) {
  					/* Mark end of the window */
  					asoc->fast_recovery_tsn = asoc->sending_seq - 1;
  				} else {
  					asoc->fast_recovery_tsn = lchk->rec.data.TSN_seq - 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_seq - 1;
  				}
  
  				sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
  						stcb->sctp_ep, stcb, net, SCTP_FROM_SCTP_INDATA+SCTP_LOC_32 );
  				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 /* Loosing to other flows */
  #define SCTP_INST_NEUTRAL 2 /* Neutral, no indication */
  #define SCTP_INST_GAINING 3 /* Gaining, step down possible */
  
  
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  static int
  cc_bw_same(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw,
  	   uint64_t rtt_offset, uint64_t vtag, uint8_t inst_ind)
  #else
  static int
  cc_bw_same(struct sctp_tcb *stcb SCTP_UNUSED, struct sctp_nets *net, uint64_t nbw,
  	   uint64_t rtt_offset, uint8_t inst_ind)
  #endif
  {
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	uint64_t oth, probepoint;
  #endif
  
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	probepoint = (((uint64_t)net->cwnd) << 32);
  #endif
  	if (net->rtt > net->cc_mod.rtcc.lbw_rtt + rtt_offset) {
  		/*
  		 * rtt increased
  		 * we don't update bw.. so we don't
  		 * update the rtt either.
  		 */
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  		/* Probe point 5 */
  		probepoint |=  ((5 << 16) | 1);
  		SDT_PROBE(sctp, cwnd, net, rttvar,
  			  vtag,
  			  ((net->cc_mod.rtcc.lbw << 32) | nbw),
  			  ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
  			  net->flight_size,
  			  probepoint);
  #endif
  		if ((net->cc_mod.rtcc.steady_step) && (inst_ind != SCTP_INST_LOOSING)) {
  			if (net->cc_mod.rtcc.last_step_state == 5)
  				net->cc_mod.rtcc.step_cnt++;
  			else
  				net->cc_mod.rtcc.step_cnt = 1;
  			net->cc_mod.rtcc.last_step_state = 5;
  			if ((net->cc_mod.rtcc.step_cnt == net->cc_mod.rtcc.steady_step) ||
  			    ((net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step) &&
  			     ((net->cc_mod.rtcc.step_cnt % net->cc_mod.rtcc.steady_step) == 0))) {
  				/* Try a step down */
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  				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_PROBE(sctp, cwnd, net, rttstep,
  					  vtag,
  					  ((net->cc_mod.rtcc.lbw << 32) | nbw),
  					  ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
  					  oth,
  					  probepoint);
  #endif
  				if (net->cwnd > (4 * net->mtu)) {
  					net->cwnd -= net->mtu;
  					net->cc_mod.rtcc.vol_reduce++;
  				} else {
  					net->cc_mod.rtcc.step_cnt = 0;
  				}
  			}
  		}
  		return (1);
  	}
  	if (net->rtt < net->cc_mod.rtcc.lbw_rtt-rtt_offset) {
  		/*
  		 * rtt decreased, there could be more room.
  		 * we update both the bw and the rtt here to
  		 * lock this in as a good step down.
  		 */
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  		/* Probe point 6 */
  		probepoint |=  ((6 << 16) | 0);
  		SDT_PROBE(sctp, cwnd, net, rttvar,
  			  vtag,
  			  ((net->cc_mod.rtcc.lbw << 32) | nbw),
  			  ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
  			  net->flight_size,
  			  probepoint);
  #endif
  		if (net->cc_mod.rtcc.steady_step) {
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  			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_PROBE(sctp, cwnd, net, rttstep,
  				  vtag,
  				  ((net->cc_mod.rtcc.lbw << 32) | nbw),
  				  ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
  				  oth,
  				  probepoint);
  #endif
  			if ((net->cc_mod.rtcc.last_step_state == 5) &&
  			    (net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step)) {
  				/* Step down worked */
  				net->cc_mod.rtcc.step_cnt = 0;
  				return (1);
  			} else {
  				net->cc_mod.rtcc.last_step_state = 6;
  				net->cc_mod.rtcc.step_cnt = 0;
  			}
  		}
  		net->cc_mod.rtcc.lbw = nbw;
  		net->cc_mod.rtcc.lbw_rtt = net->rtt;
  		net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
  		if (inst_ind == SCTP_INST_GAINING)
  			return (1);
  		else if (inst_ind == SCTP_INST_NEUTRAL)
  			return (1);
  		else
  			return (0);
  	}
  	/* Ok bw and rtt remained the same .. no update to any
  	 */
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	/* Probe point 7 */
  	probepoint |=  ((7 << 16) | net->cc_mod.rtcc.ret_from_eq);
  	SDT_PROBE(sctp, cwnd, net, rttvar,
  		  vtag,
  		  ((net->cc_mod.rtcc.lbw << 32) | nbw),
  		  ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
  		  net->flight_size,
  		  probepoint);
  #endif
  	if ((net->cc_mod.rtcc.steady_step) && (inst_ind != SCTP_INST_LOOSING)) {
  		if (net->cc_mod.rtcc.last_step_state == 5)
  			net->cc_mod.rtcc.step_cnt++;
  		else
  			net->cc_mod.rtcc.step_cnt = 1;
  		net->cc_mod.rtcc.last_step_state = 5;
  		if ((net->cc_mod.rtcc.step_cnt == net->cc_mod.rtcc.steady_step) ||
  		    ((net->cc_mod.rtcc.step_cnt > net->cc_mod.rtcc.steady_step) &&
  		     ((net->cc_mod.rtcc.step_cnt % net->cc_mod.rtcc.steady_step) == 0))) {
  			/* Try a step down */
  			if (net->cwnd > (4 * net->mtu)) {
  				net->cwnd -= net->mtu;
  				net->cc_mod.rtcc.vol_reduce++;
  				return (1);
  			} else {
  				net->cc_mod.rtcc.step_cnt = 0;
  			}
  		}
  	}
  	if (inst_ind == SCTP_INST_GAINING)
  		return (1);
  	else if (inst_ind == SCTP_INST_NEUTRAL)
  		return (1);
  	else
  		return ((int)net->cc_mod.rtcc.ret_from_eq);
  }
  
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  static int
  cc_bw_decrease(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw, uint64_t rtt_offset,
  	       uint64_t vtag, uint8_t inst_ind)
  #else
  static int
  cc_bw_decrease(struct sctp_tcb *stcb SCTP_UNUSED, struct sctp_nets *net, uint64_t nbw, uint64_t rtt_offset,
  	       uint8_t inst_ind)
  #endif
  {
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	uint64_t oth, probepoint;
  #endif
  
  	/* Bandwidth decreased.*/
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	probepoint = (((uint64_t)net->cwnd) << 32);
  #endif
  	if (net->rtt  > net->cc_mod.rtcc.lbw_rtt+rtt_offset) {
  		/* rtt increased */
  		/* Did we add more */
  		if ((net->cwnd > net->cc_mod.rtcc.cwnd_at_bw_set) &&
  		    (inst_ind != SCTP_INST_LOOSING)) {
  			/* We caused it maybe.. back off? */
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  			/* PROBE POINT 1 */
  			probepoint |=  ((1 << 16) | 1);
  			SDT_PROBE(sctp, cwnd, net, rttvar,
  				  vtag,
  				  ((net->cc_mod.rtcc.lbw << 32) | nbw),
  				  ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
  				  net->flight_size,
  				  probepoint);
  #endif
  			if (net->cc_mod.rtcc.ret_from_eq) {
  				/* Switch over to CA if we are less aggressive */
  				net->ssthresh = net->cwnd-1;
  				net->partial_bytes_acked = 0;
  			}
  			return (1);
  		}
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  		/* Probe point 2 */
  		probepoint |=  ((2 << 16) | 0);
  		SDT_PROBE(sctp, cwnd, net, rttvar,
  			  vtag,
  			  ((net->cc_mod.rtcc.lbw << 32) | nbw),
  			  ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
  			  net->flight_size,
  			  probepoint);
  #endif
  		/* Someone else - fight for more? */
  		if (net->cc_mod.rtcc.steady_step) {
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  			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_PROBE(sctp, cwnd, net, rttstep,
  				  vtag,
  				  ((net->cc_mod.rtcc.lbw << 32) | nbw),
  				  ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
  				  oth,
  				  probepoint);
  #endif
  			/* Did we voluntarily give up some? if so take
  			 * one back please
  			 */
  			if ((net->cc_mod.rtcc.vol_reduce) &&
  			    (inst_ind != SCTP_INST_GAINING)) {
  				net->cwnd += net->mtu;
  				sctp_enforce_cwnd_limit(&stcb->asoc, net);
  				net->cc_mod.rtcc.vol_reduce--;
  			}
  			net->cc_mod.rtcc.last_step_state = 2;
  			net->cc_mod.rtcc.step_cnt = 0;
  		}
  		goto out_decision;
  	} else  if (net->rtt  < net->cc_mod.rtcc.lbw_rtt-rtt_offset) {
  		/* bw & rtt decreased */
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  		/* Probe point 3 */
  		probepoint |=  ((3 << 16) | 0);
  		SDT_PROBE(sctp, cwnd, net, rttvar,
  			  vtag,
  			  ((net->cc_mod.rtcc.lbw << 32) | nbw),
  			  ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
  			  net->flight_size,
  			  probepoint);
  #endif
  		if (net->cc_mod.rtcc.steady_step) {
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  			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_PROBE(sctp, cwnd, net, rttstep,
  				  vtag,
  				  ((net->cc_mod.rtcc.lbw << 32) | nbw),
  				  ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
  				  oth,
  				  probepoint);
  #endif
  			if ((net->cc_mod.rtcc.vol_reduce) &&
  			    (inst_ind != SCTP_INST_GAINING)) {
  				net->cwnd += net->mtu;
  				sctp_enforce_cwnd_limit(&stcb->asoc, net);
  				net->cc_mod.rtcc.vol_reduce--;
  			}
  			net->cc_mod.rtcc.last_step_state = 3;
  			net->cc_mod.rtcc.step_cnt = 0;
  		}
  		goto out_decision;
  	}
  	/* The bw decreased but rtt stayed the same */
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	/* Probe point 4 */
  	probepoint |=  ((4 << 16) | 0);
  	SDT_PROBE(sctp, cwnd, net, rttvar,
  		  vtag,
  		  ((net->cc_mod.rtcc.lbw << 32) | nbw),
  		  ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
  		  net->flight_size,
  		  probepoint);
  #endif
  	if (net->cc_mod.rtcc.steady_step) {
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  		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_PROBE(sctp, cwnd, net, rttstep,
  			  vtag,
  			  ((net->cc_mod.rtcc.lbw << 32) | nbw),
  			  ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
  			  oth,
  			  probepoint);
  #endif
  		if ((net->cc_mod.rtcc.vol_reduce) &&
  		    (inst_ind != SCTP_INST_GAINING)) {
  			net->cwnd += net->mtu;
  			sctp_enforce_cwnd_limit(&stcb->asoc, net);
  			net->cc_mod.rtcc.vol_reduce--;
  		}
  		net->cc_mod.rtcc.last_step_state = 4;
  		net->cc_mod.rtcc.step_cnt = 0;
  	}
  out_decision:
  	net->cc_mod.rtcc.lbw = nbw;
  	net->cc_mod.rtcc.lbw_rtt = net->rtt;
  	net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
  	if (inst_ind == SCTP_INST_GAINING) {
  		return (1);
  	} else {
  		return (0);
  	}
  }
  
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  static int
  cc_bw_increase(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw, uint64_t vtag)
  #else
  static int
  cc_bw_increase(struct sctp_tcb *stcb SCTP_UNUSED, struct sctp_nets *net, uint64_t nbw)
  #endif
  {
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	uint64_t oth, probepoint;
  
  #endif
  	/* BW increased, so update and
  	 * return 0, since all actions in
  	 * our table say to do the normal CC
  	 * update. Note that we pay no attention to
  	 * the inst_ind since our overall sum is increasing.
  	 */
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	/* PROBE POINT 0 */
  	probepoint = (((uint64_t)net->cwnd) << 32);
  	SDT_PROBE(sctp, cwnd, net, rttvar,
  		  vtag,
  		  ((net->cc_mod.rtcc.lbw << 32) | nbw),
  		  ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
  		  net->flight_size,
  		  probepoint);
  #endif
  	if (net->cc_mod.rtcc.steady_step) {
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  		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_PROBE(sctp, cwnd, net, rttstep,
  			  vtag,
  			  ((net->cc_mod.rtcc.lbw << 32) | nbw),
  			  ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
  			  oth,
  			  probepoint);
  #endif
  		net->cc_mod.rtcc.last_step_state = 0;
  		net->cc_mod.rtcc.step_cnt = 0;
  		net->cc_mod.rtcc.vol_reduce = 0;
  	}
  	net->cc_mod.rtcc.lbw = nbw;
  	net->cc_mod.rtcc.lbw_rtt = net->rtt;
  	net->cc_mod.rtcc.cwnd_at_bw_set = net->cwnd;
  	return (0);
  }
  
  /* RTCC Algoritm to limit growth of cwnd, return
   * true if you want to NOT allow cwnd growth
   */
  static int
  cc_bw_limit(struct sctp_tcb *stcb, struct sctp_nets *net, uint64_t nbw)
  {
  	uint64_t bw_offset, rtt_offset;
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	uint64_t probepoint, rtt, vtag;
  #endif
  	uint64_t bytes_for_this_rtt, inst_bw;
  	uint64_t div, inst_off;
  	int bw_shift;
  	uint8_t inst_ind;
  	int ret;
  	/*-
  	 * Here we need to see if we want
  	 * to limit cwnd growth due to increase
  	 * in overall rtt but no increase in bw.
  	 * We use the following table to figure
  	 * out what we should do. When we return
  	 * 0, cc update goes on as planned. If we
  	 * return 1, then no cc update happens and cwnd
  	 * stays where it is at.
  	 * ----------------------------------
  	 *   BW    |    RTT   | Action
  	 * *********************************
  	 *   INC   |    INC   | return 0
  	 * ----------------------------------
  	 *   INC   |    SAME  | return 0
  	 * ----------------------------------
  	 *   INC   |    DECR  | return 0
  	 * ----------------------------------
  	 *   SAME  |    INC   | return 1
  	 * ----------------------------------
  	 *   SAME  |    SAME  | return 1
  	 * ----------------------------------
  	 *   SAME  |    DECR  | return 0
  	 * ----------------------------------
  	 *   DECR  |    INC   | return 0 or 1 based on if we caused.
  	 * ----------------------------------
  	 *   DECR  |    SAME  | return 0
  	 * ----------------------------------
  	 *   DECR  |    DECR  | return 0
  	 * ----------------------------------
  	 *
  	 * We are a bit fuzz on what an increase or
  	 * decrease is. For BW it is the same if
  	 * it did not change within 1/64th. For
  	 * RTT it stayed the same if it did not
  	 * change within 1/32nd
  	 */
  	bw_shift = SCTP_BASE_SYSCTL(sctp_rttvar_bw);
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	rtt = stcb->asoc.my_vtag;
  	vtag = (rtt << 32) | (((uint32_t)(stcb->sctp_ep->sctp_lport)) << 16) | (stcb->rport);
  	probepoint = (((uint64_t)net->cwnd) << 32);
  	rtt = net->rtt;
  #endif
  	if (net->cc_mod.rtcc.rtt_set_this_sack) {
  		net->cc_mod.rtcc.rtt_set_this_sack = 0;
  		bytes_for_this_rtt = net->cc_mod.rtcc.bw_bytes - net->cc_mod.rtcc.bw_bytes_at_last_rttc;
  		net->cc_mod.rtcc.bw_bytes_at_last_rttc = net->cc_mod.rtcc.bw_bytes;
  		if (net->rtt) {
  			div = net->rtt / 1000;
  			if (div) {
  				inst_bw = bytes_for_this_rtt / div;
  				inst_off = inst_bw >> bw_shift;
  				if (inst_bw > nbw)
  					inst_ind = SCTP_INST_GAINING;
  				else if ((inst_bw+inst_off) < nbw)
  					inst_ind = SCTP_INST_LOOSING;
  				else
  					inst_ind = SCTP_INST_NEUTRAL;
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  				probepoint |=  ((0xb << 16) | inst_ind);
  #endif
  			} else {
  				inst_ind = net->cc_mod.rtcc.last_inst_ind;
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  				inst_bw = bytes_for_this_rtt / (uint64_t)(net->rtt);
  				/* Can't determine do not change */
  				probepoint |=  ((0xc << 16) | inst_ind);
  #endif
  			}
  		} else {
  			inst_ind = net->cc_mod.rtcc.last_inst_ind;
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  			inst_bw = bytes_for_this_rtt;
  			/* Can't determine do not change */
  			probepoint |=  ((0xd << 16) | inst_ind);
  #endif
  		}
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  		SDT_PROBE(sctp, cwnd, net, rttvar,
  			  vtag,
  			  ((nbw << 32) | inst_bw),
  			  ((net->cc_mod.rtcc.lbw_rtt << 32) | rtt),
  			  net->flight_size,
  			  probepoint);
  #endif
  	} else {
  		/* No rtt measurement, use last one */
  		inst_ind = net->cc_mod.rtcc.last_inst_ind;
  	}
  	bw_offset = net->cc_mod.rtcc.lbw >> bw_shift;
  	if (nbw > net->cc_mod.rtcc.lbw + bw_offset) {
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  		ret = cc_bw_increase(stcb, net, nbw, vtag);
  #else
  		ret = cc_bw_increase(stcb, net, nbw);
  #endif
  		goto out;
  	}
  	rtt_offset = net->cc_mod.rtcc.lbw_rtt >> SCTP_BASE_SYSCTL(sctp_rttvar_rtt);
  	if (nbw < net->cc_mod.rtcc.lbw - bw_offset) {
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  		ret = cc_bw_decrease(stcb, net, nbw, rtt_offset, vtag, inst_ind);
  #else
  		ret = cc_bw_decrease(stcb, net, nbw, rtt_offset, inst_ind);
  #endif
  		goto out;
  	}
  	/* If we reach here then
  	 * we are in a situation where
  	 * the bw stayed the same.
  	 */
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	ret = cc_bw_same(stcb, net, nbw, rtt_offset, vtag, inst_ind);
  #else
  	ret = cc_bw_same(stcb, net, nbw, rtt_offset, inst_ind);
  #endif
  out:
  	net->cc_mod.rtcc.last_inst_ind = inst_ind;
  	return (ret);
  }
  
  static void
  sctp_cwnd_update_after_sack_common(struct sctp_tcb *stcb,
  				   struct sctp_association *asoc,
  				   int accum_moved, int reneged_all SCTP_UNUSED, int will_exit, int use_rtcc)
  {
  	struct sctp_nets *net;
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	int old_cwnd;
  #endif
  	uint32_t t_ssthresh, t_cwnd, 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_cwnd = 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;
  			t_cwnd += net->cwnd;
  			/* lastsa>>3;  we don't need to devide ...*/
  			srtt = net->lastsa;
  			if (srtt > 0) {
  				uint64_t tmp;
  
  				t_ucwnd_sbw += (uint64_t)net->cwnd / (uint64_t)srtt;
  				t_path_mptcp += (((uint64_t)net->cwnd) << SHIFT_MPTCP_MULTI_Z) /
  				                (((uint64_t)net->mtu) * (uint64_t)srtt);
  				tmp = (((uint64_t)net->cwnd) << SHIFT_MPTCP_MULTI_N) /
  				      ((uint64_t)net->mtu * (uint64_t)(srtt * srtt));
  				if (tmp > max_path) {
  					max_path = tmp;
  				}
  			}
  		}
  		if (t_path_mptcp > 0) {
  			mptcp_like_alpha = max_path / (t_path_mptcp * t_path_mptcp);
  		} else {
  			mptcp_like_alpha = 1;
  		}
  	}
  	if (t_ssthresh == 0) {
  		t_ssthresh = 1;
  	}
  	if (t_ucwnd_sbw == 0) {
  		t_ucwnd_sbw = 1;
  	}
  	/******************************/
  	/* update cwnd and Early FR   */
  	/******************************/
  	TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
  
  #ifdef JANA_CMT_FAST_RECOVERY
  		/*
  		 * CMT fast recovery code. Need to debug.
  		 */
  		if (net->fast_retran_loss_recovery && net->new_pseudo_cumack) {
  			if (SCTP_TSN_GE(asoc->last_acked_seq, net->fast_recovery_tsn) ||
  			    SCTP_TSN_GE(net->pseudo_cumack,net->fast_recovery_tsn)) {
  				net->will_exit_fast_recovery = 1;
  			}
  		}
  #endif
  		/* if nothing was acked on this destination skip it */
  		if (net->net_ack == 0) {
  			if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
  				sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
  			}
  			continue;
  		}
  #ifdef JANA_CMT_FAST_RECOVERY
                  /* CMT fast recovery code
  		 */
  		/*
  		  if (sctp_cmt_on_off > 0 && net->fast_retran_loss_recovery && net->will_exit_fast_recovery == 0) {
  		  @@@ Do something
  		  }
  		  else if (sctp_cmt_on_off == 0 && asoc->fast_retran_loss_recovery && will_exit == 0) {
  		*/
  #endif
  
  		if (asoc->fast_retran_loss_recovery &&
  		    (will_exit == 0) &&
  		    (asoc->sctp_cmt_on_off == 0)) {
  			/*
  			 * If we are in loss recovery we skip any cwnd
  			 * update
  			 */
  			return;
  		}
  		/*
  		 * Did any measurements go on for this network?
  		 */
  		if (use_rtcc && (net->cc_mod.rtcc.tls_needs_set > 0)) {
  			uint64_t nbw;
  			/*
  			 * At this point our bw_bytes has been updated
  			 * by incoming sack information.
  			 *
  			 * But our bw may not yet be set.
  			 *
  			 */
  			if ((net->cc_mod.rtcc.new_tot_time/1000) > 0) {
  				nbw = net->cc_mod.rtcc.bw_bytes/(net->cc_mod.rtcc.new_tot_time/1000);
  			} else {
  				nbw = net->cc_mod.rtcc.bw_bytes;
  			}
  			if (net->cc_mod.rtcc.lbw) {
  				if (cc_bw_limit(stcb, net, nbw)) {
  					/* Hold here, no update */
  					continue;
  				}
  			} else {
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  				uint64_t vtag, probepoint;
  
  				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_PROBE(sctp, cwnd, net, rttvar,
  					  vtag,
  					  nbw,
  					  ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
  					  net->flight_size,
  					  probepoint);
  #endif
  				net->cc_mod.rtcc.lbw = nbw;
  				net->cc_mod.rtcc.lbw_rtt = net->rtt;
  				if (net->cc_mod.rtcc.rtt_set_this_sack) {
  					net->cc_mod.rtcc.rtt_set_this_sack = 0;
  					net->cc_mod.rtcc.bw_bytes_at_last_rttc = net->cc_mod.rtcc.bw_bytes;
  				}
  			}
  		}
  		/*
  		 * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
  		 * moved.
  		 */
  		if (accum_moved ||
  		    ((asoc->sctp_cmt_on_off > 0) && net->new_pseudo_cumack)) {
  			/* If the cumulative ack moved we can proceed */
  			if (net->cwnd <= net->ssthresh) {
  				/* We are in slow start */
  				if (net->flight_size + net->net_ack >= net->cwnd) {
  					uint32_t limit;
  
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  					old_cwnd = net->cwnd;
  #endif
  					switch (asoc->sctp_cmt_on_off) {
  					case SCTP_CMT_RPV1:
  						limit = (uint32_t)(((uint64_t)net->mtu *
  						                    (uint64_t)SCTP_BASE_SYSCTL(sctp_L2_abc_variable) *
  						                    (uint64_t)net->ssthresh) /
  						                   (uint64_t)t_ssthresh);
  						incr = (uint32_t)(((uint64_t)net->net_ack *
  						                   (uint64_t)net->ssthresh) /
  						                  (uint64_t)t_ssthresh);
  						if (incr > limit) {
  							incr = limit;
  						}
  						if (incr == 0) {
  							incr = 1;
  						}
  						break;
  					case SCTP_CMT_RPV2:
  						/* lastsa>>3;  we don't need to divide ...*/
  						srtt = net->lastsa;
  						if (srtt == 0) {
  							srtt = 1;
  						}
  						limit = (uint32_t)(((uint64_t)net->mtu *
  						                    (uint64_t)SCTP_BASE_SYSCTL(sctp_L2_abc_variable) *
  						                    (uint64_t)net->cwnd) /
  						                   ((uint64_t)srtt * t_ucwnd_sbw));
  						                   /* INCREASE FACTOR */
  						incr = (uint32_t)(((uint64_t)net->net_ack *
  						                   (uint64_t)net->cwnd) /
  						                  ((uint64_t)srtt * t_ucwnd_sbw));
  						                  /* INCREASE FACTOR */
  						if (incr > limit) {
  							incr = limit;
  						}
  						if (incr == 0) {
  							incr = 1;
  						}
  						break;
  					case SCTP_CMT_MPTCP:
  						limit = (uint32_t)(((uint64_t)net->mtu *
  						                    mptcp_like_alpha *
  						                    (uint64_t)SCTP_BASE_SYSCTL(sctp_L2_abc_variable)) >>
  						                   SHIFT_MPTCP_MULTI);
  						incr  = (uint32_t)(((uint64_t)net->net_ack *
  						                    mptcp_like_alpha) >>
  						                   SHIFT_MPTCP_MULTI);
  						if (incr > limit) {
  							incr = limit;
  						}
  						if (incr > net->net_ack) {
  							incr = net->net_ack;
  						}
  						if (incr > net->mtu) {
  							incr = net->mtu;
  						}
  						break;
  					default:
  						incr = net->net_ack;
  						if (incr > net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable)) {
  							incr = net->mtu * SCTP_BASE_SYSCTL(sctp_L2_abc_variable);
  						}
  						break;
  					}
  					net->cwnd += incr;
  					sctp_enforce_cwnd_limit(asoc, net);
  					if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
  						sctp_log_cwnd(stcb, net, incr,
  						              SCTP_CWND_LOG_FROM_SS);
  					}
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  					SDT_PROBE(sctp, cwnd, net, ack,
  					          stcb->asoc.my_vtag,
  					          ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
  					          net,
  					          old_cwnd, net->cwnd);
  #endif
  				} else {
  					if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
  						sctp_log_cwnd(stcb, net, net->net_ack,
  							      SCTP_CWND_LOG_NOADV_SS);
  					}
  				}
  			} else {
  				/* We are in congestion avoidance */
  				/*
  				 * Add to pba
  				 */
  			        net->partial_bytes_acked += net->net_ack;
  
  				if ((net->flight_size + net->net_ack >= net->cwnd) &&
                                      (net->partial_bytes_acked >= net->cwnd)) {
  					net->partial_bytes_acked -= net->cwnd;
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  					old_cwnd = net->cwnd;
  #endif
  					switch (asoc->sctp_cmt_on_off) {
  					case SCTP_CMT_RPV1:
  						incr = (uint32_t)(((uint64_t)net->mtu *
  						                   (uint64_t)net->ssthresh) /
  						                  (uint64_t)t_ssthresh);
  						if (incr == 0) {
  							incr = 1;
  						}
  						break;
  					case SCTP_CMT_RPV2:
  						/* lastsa>>3;  we don't need to divide ... */
  						srtt = net->lastsa;
  						if (srtt == 0) {
  							srtt = 1;
  						}
  						incr = (uint32_t)((uint64_t)net->mtu *
  						                  (uint64_t)net->cwnd /
  						                  ((uint64_t)srtt *
  						                   t_ucwnd_sbw));
  						                  /* INCREASE FACTOR */
  						if (incr == 0) {
  							incr = 1;
  						}
  						break;
  					case SCTP_CMT_MPTCP:
  						incr = (uint32_t)((mptcp_like_alpha *
  						                   (uint64_t) net->cwnd) >>
  						                  SHIFT_MPTCP_MULTI);
  						if (incr > net->mtu) {
  							incr = net->mtu;
  						}
  						break;
  					default:
  						incr = net->mtu;
  						break;
  					}
  					net->cwnd += incr;
  					sctp_enforce_cwnd_limit(asoc, net);
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  					SDT_PROBE(sctp, cwnd, net, ack,
  						  stcb->asoc.my_vtag,
  						  ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
  						  net,
  						  old_cwnd, net->cwnd);
  #endif
  					if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
  						sctp_log_cwnd(stcb, net, net->mtu,
  							      SCTP_CWND_LOG_FROM_CA);
  					}
  				} else {
  					if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
  						sctp_log_cwnd(stcb, net, net->net_ack,
  							      SCTP_CWND_LOG_NOADV_CA);
  					}
  				}
  			}
  		} else {
  			if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_LOGGING_ENABLE) {
  				sctp_log_cwnd(stcb, net, net->mtu,
  					      SCTP_CWND_LOG_NO_CUMACK);
  			}
  		}
  	}
  }
  
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  static void
  sctp_cwnd_update_exit_pf_common(struct sctp_tcb *stcb, struct sctp_nets *net)
  #else
  static void
  sctp_cwnd_update_exit_pf_common(struct sctp_tcb *stcb SCTP_UNUSED, struct sctp_nets *net)
  #endif
  {
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	int old_cwnd;
  
  	old_cwnd = net->cwnd;
  #endif
  	net->cwnd = net->mtu;
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	SDT_PROBE(sctp, cwnd, net, ack,
  	          stcb->asoc.my_vtag, ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)), net,
  	          old_cwnd, net->cwnd);
  #endif
  	SCTPDBG(SCTP_DEBUG_INDATA1, "Destination %p moved from PF to reachable with cwnd %d.\n",
  	        (void *)net, net->cwnd);
  }
  
  
  static void
  sctp_cwnd_update_after_timeout(struct sctp_tcb *stcb, struct sctp_nets *net)
  {
  	int old_cwnd = net->cwnd;
  	uint32_t t_ssthresh, t_cwnd;
  	uint64_t t_ucwnd_sbw;
  
  	/* MT FIXME: Don't compute this over and over again */
  	t_ssthresh = 0;
  	t_cwnd = 0;
  	if ((stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) ||
  	    (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV2)) {
  		struct sctp_nets *lnet;
  		uint32_t srtt;
  
  		t_ucwnd_sbw = 0;
  		TAILQ_FOREACH(lnet, &stcb->asoc.nets, sctp_next) {
  			t_ssthresh += lnet->ssthresh;
  			t_cwnd += lnet->cwnd;
  			srtt = lnet->lastsa;
  			/* lastsa>>3;  we don't need to divide ... */
  			if (srtt > 0) {
  				t_ucwnd_sbw += (uint64_t)lnet->cwnd / (uint64_t)srtt;
  			}
  		}
  		if (t_ssthresh < 1) {
  			t_ssthresh = 1;
  		}
  		if (t_ucwnd_sbw < 1) {
  			t_ucwnd_sbw = 1;
  		}
  		if (stcb->asoc.sctp_cmt_on_off == SCTP_CMT_RPV1) {
  			net->ssthresh = (uint32_t)(((uint64_t)4 *
  			                            (uint64_t)net->mtu *
  			                            (uint64_t)net->ssthresh) /
  			                           (uint64_t)t_ssthresh);
  		} else {
  			uint64_t cc_delta;
  
  			srtt = net->lastsa;
  			/* lastsa>>3;  we don't need to divide ... */
  			if (srtt == 0) {
  				srtt = 1;
  			}
  			cc_delta = t_ucwnd_sbw * (uint64_t)srtt / 2;
  			if (cc_delta < t_cwnd) {
  				net->ssthresh = (uint32_t)((uint64_t)t_cwnd - cc_delta);
  			} else {
  				net->ssthresh  = net->mtu;
  			}
  		}
  		if ((net->cwnd > t_cwnd / 2) &&
  		    (net->ssthresh < net->cwnd - t_cwnd / 2)) {
  			net->ssthresh = net->cwnd - t_cwnd / 2;
  		}
  		if (net->ssthresh < net->mtu) {
  			net->ssthresh = net->mtu;
  		}
  	} else {
  		net->ssthresh = max(net->cwnd / 2, 4 * net->mtu);
  	}
  	net->cwnd = net->mtu;
  	net->partial_bytes_acked = 0;
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	SDT_PROBE(sctp, cwnd, net, to,
  		  stcb->asoc.my_vtag,
  		  ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
  		  net,
  		  old_cwnd, net->cwnd);
  #endif
  	if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
  		sctp_log_cwnd(stcb, net, net->cwnd - old_cwnd, SCTP_CWND_LOG_FROM_RTX);
  	}
  }
  
  static void
  sctp_cwnd_update_after_ecn_echo_common(struct sctp_tcb *stcb, struct sctp_nets *net,
  					    int in_window, int num_pkt_lost, int use_rtcc)
  {
  	int old_cwnd = net->cwnd;
  	if ((use_rtcc) && (net->lan_type == SCTP_LAN_LOCAL) && (net->cc_mod.rtcc.use_dccc_ecn)) {
  		/* Data center Congestion Control */
  		if (in_window == 0) {
  			/* Go to CA with the cwnd at the point we sent
  			 * the TSN that was marked with a CE.
  			 */
  			if (net->ecn_prev_cwnd < net->cwnd) {
  				/* Restore to prev cwnd */
  				net->cwnd = net->ecn_prev_cwnd - (net->mtu * num_pkt_lost);
  			} else {
  				/* Just cut in 1/2 */
  				net->cwnd /= 2;
  			}
  			/* Drop to CA */
  			net->ssthresh = net->cwnd - (num_pkt_lost * net->mtu);
  			if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
  				sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
  			}
  		} else {
  			/* Further tuning down required over the drastic orginal cut */
  			net->ssthresh -= (net->mtu * num_pkt_lost);
  			net->cwnd -= (net->mtu * num_pkt_lost);
  			if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
  				sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
  			}
  
  		}
  		SCTP_STAT_INCR(sctps_ecnereducedcwnd);
  	}  else {
  		if (in_window == 0) {
  			SCTP_STAT_INCR(sctps_ecnereducedcwnd);
  			net->ssthresh = net->cwnd / 2;
  			if (net->ssthresh < net->mtu) {
  				net->ssthresh = net->mtu;
  				/* here back off the timer as well, to slow us down */
  				net->RTO <<= 1;
  			}
  			net->cwnd = net->ssthresh;
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  			SDT_PROBE(sctp, cwnd, net, ecn,
  				  stcb->asoc.my_vtag,
  				  ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
  				  net,
  				  old_cwnd, net->cwnd);
  #endif
  			if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
  				sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
  			}
  		}
  	}
  
  }
  
  static void
  sctp_cwnd_update_after_packet_dropped(struct sctp_tcb *stcb,
  	struct sctp_nets *net, struct sctp_pktdrop_chunk *cp,
  	uint32_t *bottle_bw, uint32_t *on_queue)
  {
  	uint32_t bw_avail;
  	unsigned int incr;
  	int old_cwnd = net->cwnd;
  
  	/* get bottle neck bw */
  	*bottle_bw = ntohl(cp->bottle_bw);
  	/* and whats on queue */
  	*on_queue = ntohl(cp->current_onq);
  	/*
  	 * adjust the on-queue if our flight is more it could be
  	 * that the router has not yet gotten data "in-flight" to it
  	 */
  	if (*on_queue < net->flight_size) {
  		*on_queue = net->flight_size;
  	}
  	/* rtt is measured in micro seconds, bottle_bw in bytes per second */
  	bw_avail = (uint32_t)(((uint64_t)(*bottle_bw) * net->rtt) / (uint64_t)1000000);
  	if (bw_avail > *bottle_bw) {
  		/*
  		 * Cap the growth to no more than the bottle neck.
  		 * This can happen as RTT slides up due to queues.
  		 * It also means if you have more than a 1 second
  		 * RTT with a empty queue you will be limited to the
  		 * bottle_bw per second no matter if other points
  		 * have 1/2 the RTT and you could get more out...
  		 */
  		bw_avail = *bottle_bw;
  	}
  	if (*on_queue > bw_avail) {
  		/*
  		 * No room for anything else don't allow anything
  		 * else to be "added to the fire".
  		 */
  		int seg_inflight, seg_onqueue, my_portion;
  
  		net->partial_bytes_acked = 0;
  		/* how much are we over queue size? */
  		incr = *on_queue - bw_avail;
  		if (stcb->asoc.seen_a_sack_this_pkt) {
  			/*
  			 * undo any cwnd adjustment that the sack
  			 * might have made
  			 */
  			net->cwnd = net->prev_cwnd;
  		}
  		/* Now how much of that is mine? */
  		seg_inflight = net->flight_size / net->mtu;
  		seg_onqueue = *on_queue / net->mtu;
  		my_portion = (incr * seg_inflight) / seg_onqueue;
  
  		/* Have I made an adjustment already */
  		if (net->cwnd > net->flight_size) {
  			/*
  			 * for this flight I made an adjustment we
  			 * need to decrease the portion by a share
  			 * our previous adjustment.
  			 */
  			int diff_adj;
  
  			diff_adj = net->cwnd - net->flight_size;
  			if (diff_adj > my_portion)
  				my_portion = 0;
  			else
  				my_portion -= diff_adj;
  		}
  		/*
  		 * back down to the previous cwnd (assume we have
  		 * had a sack before this packet). minus what ever
  		 * portion of the overage is my fault.
  		 */
  		net->cwnd -= my_portion;
  
  		/* we will NOT back down more than 1 MTU */
  		if (net->cwnd <= net->mtu) {
  			net->cwnd = net->mtu;
  		}
  		/* force into CA */
  		net->ssthresh = net->cwnd - 1;
  	} else {
  		/*
  		 * Take 1/4 of the space left or max burst up ..
  		 * whichever is less.
  		 */
  		incr = (bw_avail - *on_queue) >> 2;
  		if ((stcb->asoc.max_burst > 0) &&
  		    (stcb->asoc.max_burst * net->mtu < incr)) {
  			incr = stcb->asoc.max_burst * net->mtu;
  		}
  		net->cwnd += incr;
  	}
  	if (net->cwnd > bw_avail) {
  		/* We can't exceed the pipe size */
  		net->cwnd = bw_avail;
  	}
  	if (net->cwnd < net->mtu) {
  		/* We always have 1 MTU */
  		net->cwnd = net->mtu;
  	}
  	sctp_enforce_cwnd_limit(&stcb->asoc, net);
  	if (net->cwnd - old_cwnd != 0) {
  		/* log only changes */
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  		SDT_PROBE(sctp, cwnd, net, pd,
  			  stcb->asoc.my_vtag,
  			  ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
  			  net,
  			  old_cwnd, net->cwnd);
  #endif
  		if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
  			sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
  				SCTP_CWND_LOG_FROM_SAT);
  		}
  	}
  }
  
  static void
  sctp_cwnd_update_after_output(struct sctp_tcb *stcb,
  			      struct sctp_nets *net, int burst_limit)
  {
  	int old_cwnd = net->cwnd;
  
  	if (net->ssthresh < net->cwnd)
  		net->ssthresh = net->cwnd;
  	if (burst_limit) {
  		net->cwnd = (net->flight_size + (burst_limit * net->mtu));
  		sctp_enforce_cwnd_limit(&stcb->asoc, net);
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  		SDT_PROBE(sctp, cwnd, net, bl,
  			  stcb->asoc.my_vtag,
  			  ((stcb->sctp_ep->sctp_lport << 16) | (stcb->rport)),
  			  net,
  			  old_cwnd, net->cwnd);
  #endif
  		if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_CWND_MONITOR_ENABLE) {
  			sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_BRST);
  		}
  	}
  }
  
  static void
  sctp_cwnd_update_after_sack(struct sctp_tcb *stcb,
  			    struct sctp_association *asoc,
  			    int accum_moved, int reneged_all, int will_exit)
  {
  	/* Passing a zero argument in last disables the rtcc algoritm */
  	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 algoritm */
  	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 algoritms 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 measurment going on */
  		struct timeval ltls;
  		SCTP_GETPTIME_TIMEVAL(&ltls);
  		timevalsub(&ltls, &net->cc_mod.rtcc.tls);
  		net->cc_mod.rtcc.new_tot_time = (ltls.tv_sec * 1000000) + ltls.tv_usec;
  	}
  }
  
  static void
  sctp_cwnd_new_rtcc_transmission_begins(struct sctp_tcb *stcb,
  				       struct sctp_nets *net)
  {
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	uint64_t vtag, probepoint;
  
  #endif
  	if (net->cc_mod.rtcc.lbw) {
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  		/* 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_PROBE(sctp, cwnd, net, rttvar,
  			  vtag,
  			  ((net->cc_mod.rtcc.lbw << 32) | 0),
  			  ((net->cc_mod.rtcc.lbw_rtt << 32) | net->rtt),
  			  net->flight_size,
  			  probepoint);
  #endif
  		net->cc_mod.rtcc.lbw_rtt = 0;
  		net->cc_mod.rtcc.cwnd_at_bw_set = 0;
  		net->cc_mod.rtcc.lbw = 0;
  		net->cc_mod.rtcc.bw_bytes_at_last_rttc = 0;
  		net->cc_mod.rtcc.vol_reduce = 0;
  		net->cc_mod.rtcc.bw_tot_time = 0;
  		net->cc_mod.rtcc.bw_bytes = 0;
  		net->cc_mod.rtcc.tls_needs_set = 0;
  		if (net->cc_mod.rtcc.steady_step) {
  			net->cc_mod.rtcc.vol_reduce = 0;
  			net->cc_mod.rtcc.step_cnt = 0;
  			net->cc_mod.rtcc.last_step_state = 0;
  		}
  		if (net->cc_mod.rtcc.ret_from_eq) {
  			/* less aggressive one - reset cwnd too */
  			uint32_t cwnd_in_mtu, cwnd;
  
  			cwnd_in_mtu = SCTP_BASE_SYSCTL(sctp_initial_cwnd);
  			if (cwnd_in_mtu == 0) {
  				/* Using 0 means that the value of RFC 4960 is used. */
  				cwnd = min((net->mtu * 4), max((2 * net->mtu), SCTP_INITIAL_CWND));
  			} else {
  				/*
  				 * We take the minimum of the burst limit and the
  				 * initial congestion window.
  				 */
  				if ((stcb->asoc.max_burst > 0) && (cwnd_in_mtu > stcb->asoc.max_burst))
  					cwnd_in_mtu = stcb->asoc.max_burst;
  				cwnd = (net->mtu - sizeof(struct sctphdr)) * cwnd_in_mtu;
  			}
  			if (net->cwnd > cwnd) {
  				/* Only set if we are not a timeout (i.e. down to 1 mtu) */
  				net->cwnd = cwnd;
  			}
  		}
  	}
  }
  
  static void
  sctp_set_rtcc_initial_cc_param(struct sctp_tcb *stcb,
  			       struct sctp_nets *net)
  {
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	uint64_t vtag, probepoint;
  
  #endif
  	sctp_set_initial_cc_param(stcb, net);
  	stcb->asoc.use_precise_time = 1;
  #if defined(__FreeBSD__) && __FreeBSD_version >= 1000000
  	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_PROBE(sctp, cwnd, net, rttvar,
  		  vtag,
  		  0,
  		  0,
  		  0,
  		  probepoint);
  #endif
  	net->cc_mod.rtcc.lbw_rtt = 0;
  	net->cc_mod.rtcc.cwnd_at_bw_set = 0;
  	net->cc_mod.rtcc.vol_reduce = 0;
  	net->cc_mod.rtcc.lbw = 0;
  	net->cc_mod.rtcc.vol_reduce = 0;
  	net->cc_mod.rtcc.bw_bytes_at_last_rttc = 0;
  	net->cc_mod.rtcc.bw_tot_time = 0;
  	net->cc_mod.rtcc.bw_bytes = 0;
  	net->cc_mod.rtcc.tls_needs_set = 0;
  	net->cc_mod.rtcc.ret_from_eq = SCTP_BASE_SYSCTL(sctp_rttvar_eqret);
  	net->cc_mod.rtcc.steady_step = SCTP_BASE_SYSCTL(sctp_steady_step);
  	net->cc_mod.rtcc.use_dccc_ecn = SCTP_BASE_SYSCTL(sctp_use_dccc_ecn);
  	net->cc_mod.rtcc.step_cnt = 0;
  	net->cc_mod.rtcc.last_step_state = 0;
  
  
  }
  
  static int
  sctp_cwnd_rtcc_socket_option(struct sctp_tcb *stcb, int setorget,
  			     struct sctp_cc_option *cc_opt)
  {
  	struct sctp_nets *net;
  	if (setorget == 1) {
  		/* a set */
  		if (cc_opt->option == SCTP_CC_OPT_RTCC_SETMODE) {
  			if ((cc_opt->aid_value.assoc_value != 0) &&
  			    (cc_opt->aid_value.assoc_value != 1)) {
  				return (EINVAL);
  			}
  			TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
  				net->cc_mod.rtcc.ret_from_eq = cc_opt->aid_value.assoc_value;
  			}
  		} else if (cc_opt->option == SCTP_CC_OPT_USE_DCCC_ECN) {
  			if ((cc_opt->aid_value.assoc_value != 0) &&
  			    (cc_opt->aid_value.assoc_value != 1)) {
  				return (EINVAL);
  			}
  			TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
  				net->cc_mod.rtcc.use_dccc_ecn = cc_opt->aid_value.assoc_value;
  			}
  		} else if (cc_opt->option == SCTP_CC_OPT_STEADY_STEP) {
  			TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
  				net->cc_mod.rtcc.steady_step = cc_opt->aid_value.assoc_value;
  			}
  		} else {
  			return (EINVAL);
  		}
  	} else {
  		/* a get */
  		if (cc_opt->option == SCTP_CC_OPT_RTCC_SETMODE) {
  			net = TAILQ_FIRST(&stcb->asoc.nets);
  			if (net == NULL) {
  				return (EFAULT);
  			}
  			cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.ret_from_eq;
  		} else if (cc_opt->option == SCTP_CC_OPT_USE_DCCC_ECN) {
  			net = TAILQ_FIRST(&stcb->asoc.nets);
  			if (net == NULL) {
  				return (EFAULT);
  			}
  			cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.use_dccc_ecn;
  		} else if (cc_opt->option == SCTP_CC_OPT_STEADY_STEP) {
  			net = TAILQ_FIRST(&stcb->asoc.nets);
  			if (net == NULL) {
  				return (EFAULT);
  			}
  			cc_opt->aid_value.assoc_value = net->cc_mod.rtcc.steady_step;
  		} else {
  			return (EINVAL);
  		}
  	}
  	return (0);
  }
  
  static void
  sctp_cwnd_update_rtcc_packet_transmitted(struct sctp_tcb *stcb SCTP_UNUSED,
                                           struct sctp_nets *net)
  {
  	if (net->cc_mod.rtcc.tls_needs_set == 0) {
  		SCTP_GETPTIME_TIMEVAL(&net->cc_mod.rtcc.tls);
  		net->cc_mod.rtcc.tls_needs_set = 2;
  	}
  }
  
  static void
  sctp_cwnd_update_rtcc_after_sack(struct sctp_tcb *stcb,
  				 struct sctp_association *asoc,
  				 int accum_moved, int reneged_all, int will_exit)
  {
  	/* Passing a one argument at the last enables the rtcc algoritm */
  	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;
  	int32_t increase;
  	int32_t drop_percent;
  };
  
  #define SCTP_HS_TABLE_SIZE 73
  
  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 = ((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) *
  		    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_seq - 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_seq - 1;
  				}
  
  				sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
  						stcb->sctp_ep, stcb, net, SCTP_FROM_SCTP_INDATA+SCTP_LOC_32);
  				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 (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+MSEC_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 > (uint32_t)MSEC_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)
  			factor = 1;
  	}
  
  	ca->alpha = 2*factor*((1<<7)-ca->beta);
  	if (!ca->alpha)
  		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_seq - 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_seq - 1;
  				}
  
  				sctp_timer_stop(SCTP_TIMER_TYPE_SEND,
  						stcb->sctp_ep, stcb, net, SCTP_FROM_SCTP_INDATA+SCTP_LOC_32);
  				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);
  		}
  	}
  }
  
  struct sctp_cc_functions sctp_cc_functions[] = {
  {
  #if defined(__Windows__) || defined(__Userspace_os_Windows)
  	sctp_set_initial_cc_param,
  	sctp_cwnd_update_after_sack,
  	sctp_cwnd_update_exit_pf_common,
  	sctp_cwnd_update_after_fr,
  	sctp_cwnd_update_after_timeout,
  	sctp_cwnd_update_after_ecn_echo,
  	sctp_cwnd_update_after_packet_dropped,
  	sctp_cwnd_update_after_output,
  #else
  	.sctp_set_initial_cc_param = sctp_set_initial_cc_param,
  	.sctp_cwnd_update_after_sack = sctp_cwnd_update_after_sack,
  	.sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
  	.sctp_cwnd_update_after_fr = sctp_cwnd_update_after_fr,
  	.sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
  	.sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_after_ecn_echo,
  	.sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
  	.sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
  #endif
  },
  {
  #if defined(__Windows__) || defined(__Userspace_os_Windows)
  	sctp_set_initial_cc_param,
  	sctp_hs_cwnd_update_after_sack,
  	sctp_cwnd_update_exit_pf_common,
  	sctp_hs_cwnd_update_after_fr,
  	sctp_cwnd_update_after_timeout,
  	sctp_cwnd_update_after_ecn_echo,
  	sctp_cwnd_update_after_packet_dropped,
  	sctp_cwnd_update_after_output,
  #else
  	.sctp_set_initial_cc_param = sctp_set_initial_cc_param,
  	.sctp_cwnd_update_after_sack = sctp_hs_cwnd_update_after_sack,
  	.sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
  	.sctp_cwnd_update_after_fr = sctp_hs_cwnd_update_after_fr,
  	.sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
  	.sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_after_ecn_echo,
  	.sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
  	.sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
  #endif
  },
  {
  #if defined(__Windows__) || defined(__Userspace_os_Windows)
  	sctp_htcp_set_initial_cc_param,
  	sctp_htcp_cwnd_update_after_sack,
  	sctp_cwnd_update_exit_pf_common,
  	sctp_htcp_cwnd_update_after_fr,
  	sctp_htcp_cwnd_update_after_timeout,
  	sctp_htcp_cwnd_update_after_ecn_echo,
  	sctp_cwnd_update_after_packet_dropped,
  	sctp_cwnd_update_after_output,
  #else
  	.sctp_set_initial_cc_param = sctp_htcp_set_initial_cc_param,
  	.sctp_cwnd_update_after_sack = sctp_htcp_cwnd_update_after_sack,
  	.sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
  	.sctp_cwnd_update_after_fr = sctp_htcp_cwnd_update_after_fr,
  	.sctp_cwnd_update_after_timeout = sctp_htcp_cwnd_update_after_timeout,
  	.sctp_cwnd_update_after_ecn_echo = sctp_htcp_cwnd_update_after_ecn_echo,
  	.sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
  	.sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
  #endif
  },
  {
  #if defined(__Windows__) || defined(__Userspace_os_Windows)
  	sctp_set_rtcc_initial_cc_param,
  	sctp_cwnd_update_rtcc_after_sack,
  	sctp_cwnd_update_exit_pf_common,
  	sctp_cwnd_update_after_fr,
  	sctp_cwnd_update_after_timeout,
  	sctp_cwnd_update_rtcc_after_ecn_echo,
  	sctp_cwnd_update_after_packet_dropped,
  	sctp_cwnd_update_after_output,
  	sctp_cwnd_update_rtcc_packet_transmitted,
  	sctp_cwnd_update_rtcc_tsn_acknowledged,
  	sctp_cwnd_new_rtcc_transmission_begins,
  	sctp_cwnd_prepare_rtcc_net_for_sack,
  	sctp_cwnd_rtcc_socket_option,
  	sctp_rtt_rtcc_calculated
  #else
  	.sctp_set_initial_cc_param = sctp_set_rtcc_initial_cc_param,
  	.sctp_cwnd_update_after_sack = sctp_cwnd_update_rtcc_after_sack,
  	.sctp_cwnd_update_exit_pf = sctp_cwnd_update_exit_pf_common,
  	.sctp_cwnd_update_after_fr = sctp_cwnd_update_after_fr,
  	.sctp_cwnd_update_after_timeout = sctp_cwnd_update_after_timeout,
  	.sctp_cwnd_update_after_ecn_echo = sctp_cwnd_update_rtcc_after_ecn_echo,
  	.sctp_cwnd_update_after_packet_dropped = sctp_cwnd_update_after_packet_dropped,
  	.sctp_cwnd_update_after_output = sctp_cwnd_update_after_output,
  	.sctp_cwnd_update_packet_transmitted = sctp_cwnd_update_rtcc_packet_transmitted,
  	.sctp_cwnd_update_tsn_acknowledged = sctp_cwnd_update_rtcc_tsn_acknowledged,
  	.sctp_cwnd_new_transmission_begins = sctp_cwnd_new_rtcc_transmission_begins,
  	.sctp_cwnd_prepare_net_for_sack = sctp_cwnd_prepare_rtcc_net_for_sack,
  	.sctp_cwnd_socket_option = sctp_cwnd_rtcc_socket_option,
  	.sctp_rtt_calculated = sctp_rtt_rtcc_calculated
  #endif
  }
  };
  