- Modular congestion control, with RFC2581 being the default.

- CMT_PF states added (w/sysctl to turn the PF version on)
- sctp_input.c had a missing incr of cookie case when the
  auth was bad. This meant a free was called without an
  increment to refcnt, added increment like rest of code.
- There was a case, unlikely, when the scope of the destination
  changed (this is a TSNH case). In that case, it would not free
  the alloc'ed asoc (in sctp_input.c).
- When listed addresses found a colliding cookie/Init, then
  the collided upon tcb was not unlocked in sctp_pcb.c
- Add error checking on arguments of sctp_sendx(3) to prevent it from
  referencing a NULL pointer.
- Fix an error return of sctp_sendx(3), it was returing
  ENOMEM not -1.
- Get assoc id was changed to use the sanctified socket api
  method for getting a assoc id (PEER_ADDR_INFO instead of
  PEER_ADDR_PARAMS).
- Fix it so a peeled off socket will get a proper error return
  if it trys to send to a different address then it is connected to.
- Fix so that select_a_stream can avoid an endless loop that
  could hang a caller.
- time_entered (state set time) was not being set in all cases
  to the time we went established.
Approved by:	re(ken smith)

1 files changed, 1631 insertions, 0 deletions

diff --git a/sys/netinet/sctp_cc_functions.c b/sys/netinet/sctp_cc_functions.c
new file mode 100644
index 0000000..3bc3b10
--- /dev/null
+++ b/sys/netinet/sctp_cc_functions.c
@@ -0,0 +1,1631 @@
+/*-
+ * Copyright (c) 2001-2007, by Cisco Systems, Inc. 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_cc_functions.h>
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+void
+sctp_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));
+	/* we always get at LEAST 2 MTU's */
+	if (net->cwnd < (2 * net->mtu)) {
+		net->cwnd = 2 * net->mtu;
+	}
+	net->ssthresh = stcb->asoc.peers_rwnd;
+
+	if (sctp_logging_level & (SCTP_CWND_MONITOR_ENABLE | SCTP_CWND_LOGGING_ENABLE)) {
+		sctp_log_cwnd(stcb, net, 0, SCTP_CWND_INITIALIZATION);
+	}
+}
+
+void
+sctp_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 == 1) &&
+	 * (net->fast_retran_loss_recovery == 0)))
+	 */
+	TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
+		if ((asoc->fast_retran_loss_recovery == 0) || (sctp_cmt_on_off == 1)) {
+			/* 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;
+
+				net->ssthresh = net->cwnd / 2;
+				if (net->ssthresh < (net->mtu * 2)) {
+					net->ssthresh = 2 * net->mtu;
+				}
+				net->cwnd = net->ssthresh;
+				if (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;
+				}
+
+				/*
+				 * Disable Nonce Sum Checking and store the
+				 * resync tsn
+				 */
+				asoc->nonce_sum_check = 0;
+				asoc->nonce_resync_tsn = asoc->fast_recovery_tsn + 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);
+		}
+	}
+}
+
+void
+sctp_cwnd_update_after_sack(struct sctp_tcb *stcb,
+    struct sctp_association *asoc,
+    int accum_moved, int reneged_all, 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 (compare_with_wrap(asoc->last_acked_seq,
+			    net->fast_recovery_tsn, MAX_TSN) ||
+			    (asoc->last_acked_seq == net->fast_recovery_tsn) ||
+			    compare_with_wrap(net->pseudo_cumack, net->fast_recovery_tsn, MAX_TSN) ||
+			    (net->pseudo_cumack == net->fast_recovery_tsn)) {
+				net->will_exit_fast_recovery = 1;
+			}
+		}
+#endif
+		if (sctp_early_fr) {
+			/*
+			 * So, first of all do we need to have a Early FR
+			 * timer running?
+			 */
+			if (((TAILQ_FIRST(&asoc->sent_queue)) &&
+			    (net->ref_count > 1) &&
+			    (net->flight_size < net->cwnd)) ||
+			    (reneged_all)) {
+				/*
+				 * yes, so in this case stop it if its
+				 * running, and then restart it. Reneging
+				 * all is a special case where we want to
+				 * run the Early FR timer and then force the
+				 * last few unacked to be sent, causing us
+				 * to illicit a sack with gaps to force out
+				 * the others.
+				 */
+				if (SCTP_OS_TIMER_PENDING(&net->fr_timer.timer)) {
+					SCTP_STAT_INCR(sctps_earlyfrstpidsck2);
+					sctp_timer_stop(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net,
+					    SCTP_FROM_SCTP_INDATA + SCTP_LOC_20);
+				}
+				SCTP_STAT_INCR(sctps_earlyfrstrid);
+				sctp_timer_start(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net);
+			} else {
+				/* No, stop it if its running */
+				if (SCTP_OS_TIMER_PENDING(&net->fr_timer.timer)) {
+					SCTP_STAT_INCR(sctps_earlyfrstpidsck3);
+					sctp_timer_stop(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net,
+					    SCTP_FROM_SCTP_INDATA + SCTP_LOC_21);
+				}
+			}
+		}
+		/* if nothing was acked on this destination skip it */
+		if (net->net_ack == 0) {
+			if (sctp_logging_level & SCTP_CWND_LOGGING_ENABLE) {
+				sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
+			}
+			continue;
+		}
+		if (net->net_ack2 > 0) {
+			/*
+			 * Karn's rule applies to clearing error count, this
+			 * is optional.
+			 */
+			net->error_count = 0;
+			if ((net->dest_state & SCTP_ADDR_NOT_REACHABLE) ==
+			    SCTP_ADDR_NOT_REACHABLE) {
+				/* addr came good */
+				net->dest_state &= ~SCTP_ADDR_NOT_REACHABLE;
+				net->dest_state |= SCTP_ADDR_REACHABLE;
+				sctp_ulp_notify(SCTP_NOTIFY_INTERFACE_UP, stcb,
+				    SCTP_RECEIVED_SACK, (void *)net);
+				/* now was it the primary? if so restore */
+				if (net->dest_state & SCTP_ADDR_WAS_PRIMARY) {
+					(void)sctp_set_primary_addr(stcb, (struct sockaddr *)NULL, net);
+				}
+			}
+			/*
+			 * JRS 5/14/07 - If CMT PF is on and the destination
+			 * is in PF state, set the destination to active
+			 * state and set the cwnd to one or two MTU's based
+			 * on whether PF1 or PF2 is being used.
+			 * 
+			 * Should we stop any running T3 timer here?
+			 */
+			if (sctp_cmt_pf && ((net->dest_state & SCTP_ADDR_PF) ==
+			    SCTP_ADDR_PF)) {
+				net->dest_state &= ~SCTP_ADDR_PF;
+				net->cwnd = net->mtu * sctp_cmt_pf;
+				SCTPDBG(SCTP_DEBUG_INDATA1, "Destination %p moved from PF to reachable with cwnd %d.\n",
+				    net, net->cwnd);
+				/*
+				 * Since the cwnd value is explicitly set,
+				 * skip the code that updates the cwnd
+				 * value.
+				 */
+				goto skip_cwnd_update;
+			}
+		}
+#ifdef JANA_CMT_FAST_RECOVERY
+		/*
+		 * CMT fast recovery code
+		 */
+		/*
+		 * if (sctp_cmt_on_off == 1 &&
+		 * 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 && sctp_cmt_on_off == 0) {
+			/*
+			 * If we are in loss recovery we skip any cwnd
+			 * update
+			 */
+			goto skip_cwnd_update;
+		}
+		/*
+		 * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
+		 * moved.
+		 */
+		if (accum_moved || (sctp_cmt_on_off && 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) {
+					if (net->net_ack > (net->mtu * sctp_L2_abc_variable)) {
+						net->cwnd += (net->mtu * sctp_L2_abc_variable);
+						if (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_logging_level & SCTP_CWND_MONITOR_ENABLE) {
+							sctp_log_cwnd(stcb, net, net->net_ack,
+							    SCTP_CWND_LOG_FROM_SS);
+						}
+					}
+				} else {
+					unsigned int dif;
+
+					dif = net->cwnd - (net->flight_size +
+					    net->net_ack);
+					if (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 */
+				if (net->flight_size + net->net_ack >=
+				    net->cwnd) {
+					/*
+					 * add to pba only if we had a
+					 * cwnd's worth (or so) in flight OR
+					 * the burst limit was applied.
+					 */
+					net->partial_bytes_acked +=
+					    net->net_ack;
+
+					/*
+					 * Do we need to increase (if pba is
+					 * > cwnd)?
+					 */
+					if (net->partial_bytes_acked >=
+					    net->cwnd) {
+						if (net->cwnd <
+						    net->partial_bytes_acked) {
+							net->partial_bytes_acked -=
+							    net->cwnd;
+						} else {
+							net->partial_bytes_acked =
+							    0;
+						}
+						net->cwnd += net->mtu;
+						if (sctp_logging_level & SCTP_CWND_MONITOR_ENABLE) {
+							sctp_log_cwnd(stcb, net, net->mtu,
+							    SCTP_CWND_LOG_FROM_CA);
+						}
+					} else {
+						if (sctp_logging_level & SCTP_CWND_LOGGING_ENABLE) {
+							sctp_log_cwnd(stcb, net, net->net_ack,
+							    SCTP_CWND_LOG_NOADV_CA);
+						}
+					}
+				} else {
+					unsigned int dif;
+
+					if (sctp_logging_level & SCTP_CWND_LOGGING_ENABLE) {
+						sctp_log_cwnd(stcb, net, net->net_ack,
+						    SCTP_CWND_LOG_NOADV_CA);
+					}
+					dif = net->cwnd - (net->flight_size +
+					    net->net_ack);
+				}
+			}
+		} else {
+			if (sctp_logging_level & SCTP_CWND_LOGGING_ENABLE) {
+				sctp_log_cwnd(stcb, net, net->mtu,
+				    SCTP_CWND_LOG_NO_CUMACK);
+			}
+		}
+skip_cwnd_update:
+		/*
+		 * NOW, according to Karn's rule do we need to restore the
+		 * RTO timer back? Check our net_ack2. If not set then we
+		 * have a ambiguity.. i.e. all data ack'd was sent to more
+		 * than one place.
+		 */
+		if (net->net_ack2) {
+			/* restore any doubled timers */
+			net->RTO = ((net->lastsa >> 2) + net->lastsv) >> 1;
+			if (net->RTO < stcb->asoc.minrto) {
+				net->RTO = stcb->asoc.minrto;
+			}
+			if (net->RTO > stcb->asoc.maxrto) {
+				net->RTO = stcb->asoc.maxrto;
+			}
+		}
+	}
+}
+
+void
+sctp_cwnd_update_after_timeout(struct sctp_tcb *stcb,
+    struct sctp_nets *net)
+{
+	int old_cwnd = net->cwnd;
+
+	net->ssthresh = net->cwnd >> 1;
+	if (net->ssthresh < (net->mtu << 1)) {
+		net->ssthresh = (net->mtu << 1);
+	}
+	net->cwnd = net->mtu;
+	/* floor of 1 mtu */
+	if (net->cwnd < net->mtu)
+		net->cwnd = net->mtu;
+	if (sctp_logging_level & SCTP_CWND_MONITOR_ENABLE) {
+		sctp_log_cwnd(stcb, net, net->cwnd - old_cwnd, SCTP_CWND_LOG_FROM_RTX);
+	}
+	net->partial_bytes_acked = 0;
+}
+
+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;
+
+	cur_val = net->cwnd >> 10;
+	indx = SCTP_HS_TABLE_SIZE - 1;
+#ifdef SCTP_DEBUG
+	printf("HS CC CAlled.\n");
+#endif
+	if (cur_val < sctp_cwnd_adjust[0].cwnd) {
+		/* normal mode */
+		if (net->net_ack > net->mtu) {
+			net->cwnd += net->mtu;
+			if (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_logging_level & SCTP_CWND_MONITOR_ENABLE) {
+				sctp_log_cwnd(stcb, net, net->net_ack, SCTP_CWND_LOG_FROM_SS);
+			}
+		}
+	} 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;
+		if (sctp_logging_level & SCTP_CWND_MONITOR_ENABLE) {
+			sctp_log_cwnd(stcb, net, incr, 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;
+	indx = net->last_hs_used;
+	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;
+		}
+	}
+	if (sctp_logging_level & SCTP_CWND_MONITOR_ENABLE) {
+		sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_FR);
+	}
+}
+
+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 == 1) &&
+	 * (net->fast_retran_loss_recovery == 0)))
+	 */
+	TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
+		if ((asoc->fast_retran_loss_recovery == 0) || (sctp_cmt_on_off == 1)) {
+			/* 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;
+				}
+
+				/*
+				 * Disable Nonce Sum Checking and store the
+				 * resync tsn
+				 */
+				asoc->nonce_sum_check = 0;
+				asoc->nonce_resync_tsn = asoc->fast_recovery_tsn + 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);
+		}
+	}
+}
+
+void
+sctp_hs_cwnd_update_after_sack(struct sctp_tcb *stcb,
+    struct sctp_association *asoc,
+    int accum_moved, int reneged_all, 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 (compare_with_wrap(asoc->last_acked_seq,
+			    net->fast_recovery_tsn, MAX_TSN) ||
+			    (asoc->last_acked_seq == net->fast_recovery_tsn) ||
+			    compare_with_wrap(net->pseudo_cumack, net->fast_recovery_tsn, MAX_TSN) ||
+			    (net->pseudo_cumack == net->fast_recovery_tsn)) {
+				net->will_exit_fast_recovery = 1;
+			}
+		}
+#endif
+		if (sctp_early_fr) {
+			/*
+			 * So, first of all do we need to have a Early FR
+			 * timer running?
+			 */
+			if (((TAILQ_FIRST(&asoc->sent_queue)) &&
+			    (net->ref_count > 1) &&
+			    (net->flight_size < net->cwnd)) ||
+			    (reneged_all)) {
+				/*
+				 * yes, so in this case stop it if its
+				 * running, and then restart it. Reneging
+				 * all is a special case where we want to
+				 * run the Early FR timer and then force the
+				 * last few unacked to be sent, causing us
+				 * to illicit a sack with gaps to force out
+				 * the others.
+				 */
+				if (SCTP_OS_TIMER_PENDING(&net->fr_timer.timer)) {
+					SCTP_STAT_INCR(sctps_earlyfrstpidsck2);
+					sctp_timer_stop(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net,
+					    SCTP_FROM_SCTP_INDATA + SCTP_LOC_20);
+				}
+				SCTP_STAT_INCR(sctps_earlyfrstrid);
+				sctp_timer_start(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net);
+			} else {
+				/* No, stop it if its running */
+				if (SCTP_OS_TIMER_PENDING(&net->fr_timer.timer)) {
+					SCTP_STAT_INCR(sctps_earlyfrstpidsck3);
+					sctp_timer_stop(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net,
+					    SCTP_FROM_SCTP_INDATA + SCTP_LOC_21);
+				}
+			}
+		}
+		/* if nothing was acked on this destination skip it */
+		if (net->net_ack == 0) {
+			if (sctp_logging_level & SCTP_CWND_LOGGING_ENABLE) {
+				sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
+			}
+			continue;
+		}
+		if (net->net_ack2 > 0) {
+			/*
+			 * Karn's rule applies to clearing error count, this
+			 * is optional.
+			 */
+			net->error_count = 0;
+			if ((net->dest_state & SCTP_ADDR_NOT_REACHABLE) ==
+			    SCTP_ADDR_NOT_REACHABLE) {
+				/* addr came good */
+				net->dest_state &= ~SCTP_ADDR_NOT_REACHABLE;
+				net->dest_state |= SCTP_ADDR_REACHABLE;
+				sctp_ulp_notify(SCTP_NOTIFY_INTERFACE_UP, stcb,
+				    SCTP_RECEIVED_SACK, (void *)net);
+				/* now was it the primary? if so restore */
+				if (net->dest_state & SCTP_ADDR_WAS_PRIMARY) {
+					(void)sctp_set_primary_addr(stcb, (struct sockaddr *)NULL, net);
+				}
+			}
+			/*
+			 * JRS 5/14/07 - If CMT PF is on and the destination
+			 * is in PF state, set the destination to active
+			 * state and set the cwnd to one or two MTU's based
+			 * on whether PF1 or PF2 is being used.
+			 * 
+			 * Should we stop any running T3 timer here?
+			 */
+			if (sctp_cmt_pf && ((net->dest_state & SCTP_ADDR_PF) ==
+			    SCTP_ADDR_PF)) {
+				net->dest_state &= ~SCTP_ADDR_PF;
+				net->cwnd = net->mtu * sctp_cmt_pf;
+				SCTPDBG(SCTP_DEBUG_INDATA1, "Destination %p moved from PF to reachable with cwnd %d.\n",
+				    net, net->cwnd);
+				/*
+				 * Since the cwnd value is explicitly set,
+				 * skip the code that updates the cwnd
+				 * value.
+				 */
+				goto skip_cwnd_update;
+			}
+		}
+#ifdef JANA_CMT_FAST_RECOVERY
+		/*
+		 * CMT fast recovery code
+		 */
+		/*
+		 * if (sctp_cmt_on_off == 1 &&
+		 * 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 && sctp_cmt_on_off == 0) {
+			/*
+			 * If we are in loss recovery we skip any cwnd
+			 * update
+			 */
+			goto skip_cwnd_update;
+		}
+		/*
+		 * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
+		 * moved.
+		 */
+		if (accum_moved || (sctp_cmt_on_off && 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 {
+					unsigned int dif;
+
+					dif = net->cwnd - (net->flight_size +
+					    net->net_ack);
+					if (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 */
+				if (net->flight_size + net->net_ack >=
+				    net->cwnd) {
+					/*
+					 * add to pba only if we had a
+					 * cwnd's worth (or so) in flight OR
+					 * the burst limit was applied.
+					 */
+					net->partial_bytes_acked +=
+					    net->net_ack;
+
+					/*
+					 * Do we need to increase (if pba is
+					 * > cwnd)?
+					 */
+					if (net->partial_bytes_acked >=
+					    net->cwnd) {
+						if (net->cwnd <
+						    net->partial_bytes_acked) {
+							net->partial_bytes_acked -=
+							    net->cwnd;
+						} else {
+							net->partial_bytes_acked =
+							    0;
+						}
+						net->cwnd += net->mtu;
+						if (sctp_logging_level & SCTP_CWND_MONITOR_ENABLE) {
+							sctp_log_cwnd(stcb, net, net->mtu,
+							    SCTP_CWND_LOG_FROM_CA);
+						}
+					} else {
+						if (sctp_logging_level & SCTP_CWND_LOGGING_ENABLE) {
+							sctp_log_cwnd(stcb, net, net->net_ack,
+							    SCTP_CWND_LOG_NOADV_CA);
+						}
+					}
+				} else {
+					unsigned int dif;
+
+					if (sctp_logging_level & SCTP_CWND_LOGGING_ENABLE) {
+						sctp_log_cwnd(stcb, net, net->net_ack,
+						    SCTP_CWND_LOG_NOADV_CA);
+					}
+					dif = net->cwnd - (net->flight_size +
+					    net->net_ack);
+				}
+			}
+		} else {
+			if (sctp_logging_level & SCTP_CWND_LOGGING_ENABLE) {
+				sctp_log_cwnd(stcb, net, net->mtu,
+				    SCTP_CWND_LOG_NO_CUMACK);
+			}
+		}
+skip_cwnd_update:
+		/*
+		 * NOW, according to Karn's rule do we need to restore the
+		 * RTO timer back? Check our net_ack2. If not set then we
+		 * have a ambiguity.. i.e. all data ack'd was sent to more
+		 * than one place.
+		 */
+		if (net->net_ack2) {
+			/* restore any doubled timers */
+			net->RTO = ((net->lastsa >> 2) + net->lastsv) >> 1;
+			if (net->RTO < stcb->asoc.minrto) {
+				net->RTO = stcb->asoc.minrto;
+			}
+			if (net->RTO > stcb->asoc.maxrto) {
+				net->RTO = stcb->asoc.maxrto;
+			}
+		}
+	}
+}
+
+void
+sctp_cwnd_update_after_ecn_echo(struct sctp_tcb *stcb,
+    struct sctp_nets *net)
+{
+	int old_cwnd;
+
+	old_cwnd = net->cwnd;
+
+	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 (sctp_logging_level & SCTP_CWND_MONITOR_ENABLE) {
+		sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
+	}
+}
+
+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;
+	int rtt, incr;
+	int old_cwnd = net->cwnd;
+
+	/* need real RTT for this calc */
+	rtt = ((net->lastsa >> 2) + net->lastsv) >> 1;
+	/* 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;
+	/* calculate the available space */
+	bw_avail = (*bottle_bw * rtt) / 1000;
+	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 = min((bw_avail - *on_queue) >> 2,
+		    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;
+	}
+	if (net->cwnd - old_cwnd != 0) {
+		/* log only changes */
+		if (sctp_logging_level & SCTP_CWND_MONITOR_ENABLE) {
+			sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd),
+			    SCTP_CWND_LOG_FROM_SAT);
+		}
+	}
+}
+
+void
+sctp_cwnd_update_after_output(struct sctp_tcb *stcb,
+    struct sctp_nets *net, int burst_limit)
+{
+	int old_cwnd;
+
+	if (net->ssthresh < net->cwnd)
+		net->ssthresh = net->cwnd;
+	old_cwnd = net->cwnd;
+	net->cwnd = (net->flight_size + (burst_limit * net->mtu));
+
+	if (sctp_logging_level & SCTP_CWND_MONITOR_ENABLE) {
+		sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_BRST);
+	}
+}
+
+void
+sctp_cwnd_update_after_fr_timer(struct sctp_inpcb *inp,
+    struct sctp_tcb *stcb, struct sctp_nets *net)
+{
+	int old_cwnd;
+
+	old_cwnd = net->cwnd;
+
+	sctp_chunk_output(inp, stcb, SCTP_OUTPUT_FROM_EARLY_FR_TMR);
+	/*
+	 * make a small adjustment to cwnd and force to CA.
+	 */
+	if (net->cwnd > net->mtu)
+		/* drop down one MTU after sending */
+		net->cwnd -= net->mtu;
+	if (net->cwnd < net->ssthresh)
+		/* still in SS move to CA */
+		net->ssthresh = net->cwnd - 1;
+	if (sctp_logging_level & SCTP_CWND_MONITOR_ENABLE) {
+		sctp_log_cwnd(stcb, net, (old_cwnd - net->cwnd), SCTP_CWND_LOG_FROM_FR);
+	}
+}
+
+/*
+ * 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 ticks - 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 = ticks;
+}
+
+#ifdef SCTP_NOT_USED
+
+static uint32_t
+htcp_cwnd_undo(struct sctp_tcb *stcb, struct sctp_nets *net)
+{
+	net->htcp_ca.last_cong = net->htcp_ca.undo_last_cong;
+	net->htcp_ca.maxRTT = net->htcp_ca.undo_maxRTT;
+	net->htcp_ca.old_maxB = net->htcp_ca.undo_old_maxB;
+	return max(net->cwnd, ((net->ssthresh / net->mtu << 7) / net->htcp_ca.beta) * net->mtu);
+}
+
+#endif
+
+static inline void
+measure_rtt(struct sctp_tcb *stcb, struct sctp_nets *net)
+{
+	uint32_t srtt = net->lastsa >> 3;
+
+	/* keep track of minimum RTT seen so far, minRTT is zero at first */
+	if (net->htcp_ca.minRTT > srtt || !net->htcp_ca.minRTT)
+		net->htcp_ca.minRTT = srtt;
+
+	/* max RTT */
+	if (net->fast_retran_ip == 0 && net->ssthresh < 0xFFFF && htcp_ccount(&net->htcp_ca) > 3) {
+		if (net->htcp_ca.maxRTT < net->htcp_ca.minRTT)
+			net->htcp_ca.maxRTT = net->htcp_ca.minRTT;
+		if (net->htcp_ca.maxRTT < srtt && srtt <= net->htcp_ca.maxRTT + MSEC_TO_TICKS(20))
+			net->htcp_ca.maxRTT = srtt;
+	}
+}
+
+static void
+measure_achieved_throughput(struct sctp_tcb *stcb, struct sctp_nets *net)
+{
+	uint32_t now = ticks;
+
+	if (net->fast_retran_ip == 0)
+		net->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->htcp_ca.bytecount = 0;
+		net->htcp_ca.lasttime = now;
+		return;
+	}
+	net->htcp_ca.bytecount += net->net_ack;
+
+	if (net->htcp_ca.bytecount >= net->cwnd - ((net->htcp_ca.alpha >> 7 ? : 1) * net->mtu)
+	    && now - net->htcp_ca.lasttime >= net->htcp_ca.minRTT
+	    && net->htcp_ca.minRTT > 0) {
+		uint32_t cur_Bi = net->htcp_ca.bytecount / net->mtu * hz / (now - net->htcp_ca.lasttime);
+
+		if (htcp_ccount(&net->htcp_ca) <= 3) {
+			/* just after backoff */
+			net->htcp_ca.minB = net->htcp_ca.maxB = net->htcp_ca.Bi = cur_Bi;
+		} else {
+			net->htcp_ca.Bi = (3 * net->htcp_ca.Bi + cur_Bi) / 4;
+			if (net->htcp_ca.Bi > net->htcp_ca.maxB)
+				net->htcp_ca.maxB = net->htcp_ca.Bi;
+			if (net->htcp_ca.minB > net->htcp_ca.maxB)
+				net->htcp_ca.minB = net->htcp_ca.maxB;
+		}
+		net->htcp_ca.bytecount = 0;
+		net->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_tcb *stcb, struct sctp_nets *net)
+{
+	uint32_t minRTT = net->htcp_ca.minRTT;
+	uint32_t maxRTT = net->htcp_ca.maxRTT;
+
+	htcp_beta_update(&net->htcp_ca, minRTT, maxRTT);
+	htcp_alpha_update(&net->htcp_ca);
+
+	/*
+	 * add slowly fading memory for maxRTT to accommodate routing
+	 * changes etc
+	 */
+	if (minRTT > 0 && maxRTT > minRTT)
+		net->htcp_ca.maxRTT = minRTT + ((maxRTT - minRTT) * 95) / 100;
+}
+
+static uint32_t
+htcp_recalc_ssthresh(struct sctp_tcb *stcb, struct sctp_nets *net)
+{
+	htcp_param_update(stcb, net);
+	return max(((net->cwnd / net->mtu * net->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_L2_abc_variable)) {
+				net->cwnd += (net->mtu * sctp_L2_abc_variable);
+				if (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_logging_level & SCTP_CWND_MONITOR_ENABLE) {
+					sctp_log_cwnd(stcb, net, net->net_ack,
+					    SCTP_CWND_LOG_FROM_SS);
+				}
+			}
+		} else {
+			unsigned int dif;
+
+			dif = net->cwnd - (net->flight_size +
+			    net->net_ack);
+			if (sctp_logging_level & SCTP_CWND_LOGGING_ENABLE) {
+				sctp_log_cwnd(stcb, net, net->net_ack,
+				    SCTP_CWND_LOG_NOADV_SS);
+			}
+		}
+	} else {
+		measure_rtt(stcb, 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->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;
+			htcp_alpha_update(&net->htcp_ca);
+			if (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_logging_level & SCTP_CWND_LOGGING_ENABLE) {
+				sctp_log_cwnd(stcb, net, net->net_ack,
+				    SCTP_CWND_LOG_NOADV_CA);
+			}
+		}
+
+		net->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_tcb *stcb, struct sctp_nets *net)
+{
+	memset(&net->htcp_ca, 0, sizeof(struct htcp));
+	net->htcp_ca.alpha = ALPHA_BASE;
+	net->htcp_ca.beta = BETA_MIN;
+	net->htcp_ca.bytes_acked = net->mtu;
+	net->htcp_ca.last_cong = ticks;
+}
+
+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));
+	/* we always get at LEAST 2 MTU's */
+	if (net->cwnd < (2 * net->mtu)) {
+		net->cwnd = 2 * net->mtu;
+	}
+	net->ssthresh = stcb->asoc.peers_rwnd;
+	htcp_init(stcb, net);
+
+	if (sctp_logging_level & (SCTP_CWND_MONITOR_ENABLE | SCTP_CWND_LOGGING_ENABLE)) {
+		sctp_log_cwnd(stcb, net, 0, SCTP_CWND_INITIALIZATION);
+	}
+}
+
+void
+sctp_htcp_cwnd_update_after_sack(struct sctp_tcb *stcb,
+    struct sctp_association *asoc,
+    int accum_moved, int reneged_all, 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 (compare_with_wrap(asoc->last_acked_seq,
+			    net->fast_recovery_tsn, MAX_TSN) ||
+			    (asoc->last_acked_seq == net->fast_recovery_tsn) ||
+			    compare_with_wrap(net->pseudo_cumack, net->fast_recovery_tsn, MAX_TSN) ||
+			    (net->pseudo_cumack == net->fast_recovery_tsn)) {
+				net->will_exit_fast_recovery = 1;
+			}
+		}
+#endif
+		if (sctp_early_fr) {
+			/*
+			 * So, first of all do we need to have a Early FR
+			 * timer running?
+			 */
+			if (((TAILQ_FIRST(&asoc->sent_queue)) &&
+			    (net->ref_count > 1) &&
+			    (net->flight_size < net->cwnd)) ||
+			    (reneged_all)) {
+				/*
+				 * yes, so in this case stop it if its
+				 * running, and then restart it. Reneging
+				 * all is a special case where we want to
+				 * run the Early FR timer and then force the
+				 * last few unacked to be sent, causing us
+				 * to illicit a sack with gaps to force out
+				 * the others.
+				 */
+				if (SCTP_OS_TIMER_PENDING(&net->fr_timer.timer)) {
+					SCTP_STAT_INCR(sctps_earlyfrstpidsck2);
+					sctp_timer_stop(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net,
+					    SCTP_FROM_SCTP_INDATA + SCTP_LOC_20);
+				}
+				SCTP_STAT_INCR(sctps_earlyfrstrid);
+				sctp_timer_start(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net);
+			} else {
+				/* No, stop it if its running */
+				if (SCTP_OS_TIMER_PENDING(&net->fr_timer.timer)) {
+					SCTP_STAT_INCR(sctps_earlyfrstpidsck3);
+					sctp_timer_stop(SCTP_TIMER_TYPE_EARLYFR, stcb->sctp_ep, stcb, net,
+					    SCTP_FROM_SCTP_INDATA + SCTP_LOC_21);
+				}
+			}
+		}
+		/* if nothing was acked on this destination skip it */
+		if (net->net_ack == 0) {
+			if (sctp_logging_level & SCTP_CWND_LOGGING_ENABLE) {
+				sctp_log_cwnd(stcb, net, 0, SCTP_CWND_LOG_FROM_SACK);
+			}
+			continue;
+		}
+		if (net->net_ack2 > 0) {
+			/*
+			 * Karn's rule applies to clearing error count, this
+			 * is optional.
+			 */
+			net->error_count = 0;
+			if ((net->dest_state & SCTP_ADDR_NOT_REACHABLE) ==
+			    SCTP_ADDR_NOT_REACHABLE) {
+				/* addr came good */
+				net->dest_state &= ~SCTP_ADDR_NOT_REACHABLE;
+				net->dest_state |= SCTP_ADDR_REACHABLE;
+				sctp_ulp_notify(SCTP_NOTIFY_INTERFACE_UP, stcb,
+				    SCTP_RECEIVED_SACK, (void *)net);
+				/* now was it the primary? if so restore */
+				if (net->dest_state & SCTP_ADDR_WAS_PRIMARY) {
+					(void)sctp_set_primary_addr(stcb, (struct sockaddr *)NULL, net);
+				}
+			}
+			/*
+			 * JRS 5/14/07 - If CMT PF is on and the destination
+			 * is in PF state, set the destination to active
+			 * state and set the cwnd to one or two MTU's based
+			 * on whether PF1 or PF2 is being used.
+			 * 
+			 * Should we stop any running T3 timer here?
+			 */
+			if (sctp_cmt_pf && ((net->dest_state & SCTP_ADDR_PF) ==
+			    SCTP_ADDR_PF)) {
+				net->dest_state &= ~SCTP_ADDR_PF;
+				net->cwnd = net->mtu * sctp_cmt_pf;
+				SCTPDBG(SCTP_DEBUG_INDATA1, "Destination %p moved from PF to reachable with cwnd %d.\n",
+				    net, net->cwnd);
+				/*
+				 * Since the cwnd value is explicitly set,
+				 * skip the code that updates the cwnd
+				 * value.
+				 */
+				goto skip_cwnd_update;
+			}
+		}
+#ifdef JANA_CMT_FAST_RECOVERY
+		/*
+		 * CMT fast recovery code
+		 */
+		/*
+		 * if (sctp_cmt_on_off == 1 &&
+		 * 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 && sctp_cmt_on_off == 0) {
+			/*
+			 * If we are in loss recovery we skip any cwnd
+			 * update
+			 */
+			goto skip_cwnd_update;
+		}
+		/*
+		 * CMT: CUC algorithm. Update cwnd if pseudo-cumack has
+		 * moved.
+		 */
+		if (accum_moved || (sctp_cmt_on_off && net->new_pseudo_cumack)) {
+			htcp_cong_avoid(stcb, net);
+			measure_achieved_throughput(stcb, net);
+		} else {
+			if (sctp_logging_level & SCTP_CWND_LOGGING_ENABLE) {
+				sctp_log_cwnd(stcb, net, net->mtu,
+				    SCTP_CWND_LOG_NO_CUMACK);
+			}
+		}
+skip_cwnd_update:
+		/*
+		 * NOW, according to Karn's rule do we need to restore the
+		 * RTO timer back? Check our net_ack2. If not set then we
+		 * have a ambiguity.. i.e. all data ack'd was sent to more
+		 * than one place.
+		 */
+		if (net->net_ack2) {
+			/* restore any doubled timers */
+			net->RTO = ((net->lastsa >> 2) + net->lastsv) >> 1;
+			if (net->RTO < stcb->asoc.minrto) {
+				net->RTO = stcb->asoc.minrto;
+			}
+			if (net->RTO > stcb->asoc.maxrto) {
+				net->RTO = stcb->asoc.maxrto;
+			}
+		}
+	}
+}
+
+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 == 1) &&
+	 * (net->fast_retran_loss_recovery == 0)))
+	 */
+	TAILQ_FOREACH(net, &asoc->nets, sctp_next) {
+		if ((asoc->fast_retran_loss_recovery == 0) || (sctp_cmt_on_off == 1)) {
+			/* 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->htcp_ca);
+				net->ssthresh = htcp_recalc_ssthresh(stcb, net);
+				net->cwnd = net->ssthresh;
+				if (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;
+				}
+
+				/*
+				 * Disable Nonce Sum Checking and store the
+				 * resync tsn
+				 */
+				asoc->nonce_sum_check = 0;
+				asoc->nonce_resync_tsn = asoc->fast_recovery_tsn + 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);
+		}
+	}
+}
+
+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->htcp_ca);
+	net->ssthresh = htcp_recalc_ssthresh(stcb, net);
+	net->cwnd = net->mtu;
+	/* floor of 1 mtu */
+	if (net->cwnd < net->mtu)
+		net->cwnd = net->mtu;
+	if (sctp_logging_level & SCTP_CWND_MONITOR_ENABLE) {
+		sctp_log_cwnd(stcb, net, net->cwnd - old_cwnd, SCTP_CWND_LOG_FROM_RTX);
+	}
+	net->partial_bytes_acked = 0;
+}
+
+void
+sctp_htcp_cwnd_update_after_fr_timer(struct sctp_inpcb *inp,
+    struct sctp_tcb *stcb, struct sctp_nets *net)
+{
+	int old_cwnd;
+
+	old_cwnd = net->cwnd;
+
+	sctp_chunk_output(inp, stcb, SCTP_OUTPUT_FROM_EARLY_FR_TMR);
+	net->htcp_ca.last_cong = ticks;
+	/*
+	 * make a small adjustment to cwnd and force to CA.
+	 */
+	if (net->cwnd > net->mtu)
+		/* drop down one MTU after sending */
+		net->cwnd -= net->mtu;
+	if (net->cwnd < net->ssthresh)
+		/* still in SS move to CA */
+		net->ssthresh = net->cwnd - 1;
+	if (sctp_logging_level & SCTP_CWND_MONITOR_ENABLE) {
+		sctp_log_cwnd(stcb, net, (old_cwnd - net->cwnd), SCTP_CWND_LOG_FROM_FR);
+	}
+}
+
+void
+sctp_htcp_cwnd_update_after_ecn_echo(struct sctp_tcb *stcb,
+    struct sctp_nets *net)
+{
+	int old_cwnd;
+
+	old_cwnd = net->cwnd;
+
+	/* JRS - reset hctp as if state changed */
+	htcp_reset(&net->htcp_ca);
+	SCTP_STAT_INCR(sctps_ecnereducedcwnd);
+	net->ssthresh = htcp_recalc_ssthresh(stcb, 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;
+	if (sctp_logging_level & SCTP_CWND_MONITOR_ENABLE) {
+		sctp_log_cwnd(stcb, net, (net->cwnd - old_cwnd), SCTP_CWND_LOG_FROM_SAT);
+	}
+}