 @@ -1,985 +1,985 @@
-/*	$NetBSD: tcp_congctl.c,v 1.26 2018/09/03 16:29:36 riastradh Exp $	*/
+/*	$NetBSD: tcp_congctl.c,v 1.27 2019/10/09 05:29:18 msaitoh Exp $	*/
 /*-
  * Copyright (c) 1997, 1998, 1999, 2001, 2005, 2006 The NetBSD Foundation, Inc.
  * All rights reserved.
+ *
  * This code is derived from software contributed to The NetBSD Foundation
  * by Jason R. Thorpe and Kevin M. Lahey of the Numerical Aerospace Simulation
  * Facility, NASA Ames Research Center.
  * This code is derived from software contributed to The NetBSD Foundation
  * by Charles M. Hannum.
  * This code is derived from software contributed to The NetBSD Foundation
  * by Rui Paulo.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. 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.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
  */
 /*
  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. 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.
  * 3. Neither the name of the project 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 PROJECT 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 PROJECT 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.
  */
 /*
  *      @(#)COPYRIGHT   1.1 (NRL) 17 January 1995
+ *
  * NRL grants permission for redistribution and use in source and binary
  * forms, with or without modification, of the software and documentation
  * created at NRL provided that the following conditions are met:
+ *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. 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.
  * 3. All advertising materials mentioning features or use of this software
  *    must display the following acknowledgements:
  *      This product includes software developed by the University of
  *      California, Berkeley and its contributors.
  *      This product includes software developed at the Information
  *      Technology Division, US Naval Research Laboratory.
  * 4. Neither the name of the NRL nor the names of its contributors
  *    may be used to endorse or promote products derived from this software
  *    without specific prior written permission.
+ *
  * THE SOFTWARE PROVIDED BY NRL IS PROVIDED BY NRL 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 NRL 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.
+ *
  * The views and conclusions contained in the software and documentation
  * are those of the authors and should not be interpreted as representing
  * official policies, either expressed or implied, of the US Naval
  * Research Laboratory (NRL).
  */
 /*
  * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994, 1995
  *	The Regents of the University of California.  All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. 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.
  * 3. Neither the name of the University 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 REGENTS 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 REGENTS 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.
+ *
  *	@(#)tcp_input.c	8.12 (Berkeley) 5/24/95
  */
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: tcp_congctl.c,v 1.26 2018/09/03 16:29:36 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: tcp_congctl.c,v 1.27 2019/10/09 05:29:18 msaitoh Exp $");
 #ifdef _KERNEL_OPT
 #include "opt_inet.h"
 #include "opt_tcp_debug.h"
 #include "opt_tcp_congctl.h"
 #endif
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/malloc.h>
 #include <sys/mbuf.h>
 #include <sys/protosw.h>
 #include <sys/socket.h>
 #include <sys/socketvar.h>
 #include <sys/errno.h>
 #include <sys/syslog.h>
 #include <sys/pool.h>
 #include <sys/domain.h>
 #include <sys/kernel.h>
 #include <sys/mutex.h>
 #include <net/if.h>
 #include <netinet/in.h>
 #include <netinet/in_systm.h>
 #include <netinet/ip.h>
 #include <netinet/in_pcb.h>
 #include <netinet/in_var.h>
 #include <netinet/ip_var.h>
 #ifdef INET6
 #include <netinet/ip6.h>
 #include <netinet6/ip6_var.h>
 #include <netinet6/in6_pcb.h>
 #include <netinet6/ip6_var.h>
 #include <netinet6/in6_var.h>
 #include <netinet/icmp6.h>
 #endif
 #include <netinet/tcp.h>
 #include <netinet/tcp_fsm.h>
 #include <netinet/tcp_seq.h>
 #include <netinet/tcp_timer.h>
 #include <netinet/tcp_var.h>
 #include <netinet/tcp_congctl.h>
 #ifdef TCP_DEBUG
 #include <netinet/tcp_debug.h>
 #endif
 /*
  * TODO:
  *   consider separating the actual implementations in another file.
  */
 static void tcp_common_congestion_exp(struct tcpcb *, int, int);
 static int  tcp_reno_do_fast_retransmit(struct tcpcb *, const struct tcphdr *);
 static int  tcp_reno_fast_retransmit(struct tcpcb *, const struct tcphdr *);
 static void tcp_reno_slow_retransmit(struct tcpcb *);
 static void tcp_reno_fast_retransmit_newack(struct tcpcb *,
     const struct tcphdr *);
 static void tcp_reno_newack(struct tcpcb *, const struct tcphdr *);
 static void tcp_reno_congestion_exp(struct tcpcb *tp);
 static int  tcp_newreno_fast_retransmit(struct tcpcb *, const struct tcphdr *);
 static void tcp_newreno_fast_retransmit_newack(struct tcpcb *,
 	const struct tcphdr *);
 static void tcp_newreno_newack(struct tcpcb *, const struct tcphdr *);
 static int tcp_cubic_fast_retransmit(struct tcpcb *, const struct tcphdr *);
 static void tcp_cubic_slow_retransmit(struct tcpcb *tp);
 static void tcp_cubic_newack(struct tcpcb *, const struct tcphdr *);
 static void tcp_cubic_congestion_exp(struct tcpcb *);
 static void tcp_congctl_fillnames(void);
 extern int tcprexmtthresh;
 MALLOC_DEFINE(M_TCPCONGCTL, "tcpcongctl", "TCP congestion control structures");
 /* currently selected global congestion control */
 char tcp_congctl_global_name[TCPCC_MAXLEN];
 /* available global congestion control algorithms */
 char tcp_congctl_avail[10 * TCPCC_MAXLEN];
 /*
  * Used to list the available congestion control algorithms.
  */
 TAILQ_HEAD(, tcp_congctlent) tcp_congctlhd =
     TAILQ_HEAD_INITIALIZER(tcp_congctlhd);
 static struct tcp_congctlent * tcp_congctl_global;
 static kmutex_t tcp_congctl_mtx;
 void
 tcp_congctl_init(void)
+{
 	int r __diagused;
 	mutex_init(&tcp_congctl_mtx, MUTEX_DEFAULT, IPL_NONE);
 	/* Base algorithms. */
 	r = tcp_congctl_register("reno", &tcp_reno_ctl);
 	KASSERT(r == 0);
 	r = tcp_congctl_register("newreno", &tcp_newreno_ctl);
 	KASSERT(r == 0);
 	r = tcp_congctl_register("cubic", &tcp_cubic_ctl);
 	KASSERT(r == 0);
 	/* NewReno is the default. */
 #ifndef TCP_CONGCTL_DEFAULT
 #define TCP_CONGCTL_DEFAULT "newreno"
 #endif
 	r = tcp_congctl_select(NULL, TCP_CONGCTL_DEFAULT);
 	KASSERT(r == 0);
+}
 /*
  * Register a congestion algorithm and select it if we have none.
  */
 int
 tcp_congctl_register(const char *name, const struct tcp_congctl *tcc)
+{
 	struct tcp_congctlent *ntcc, *tccp;
 	TAILQ_FOREACH(tccp, &tcp_congctlhd, congctl_ent)
 		if (!strcmp(name, tccp->congctl_name)) {
 			/* name already registered */
 			return EEXIST;
+		}
 	ntcc = malloc(sizeof(*ntcc), M_TCPCONGCTL, M_WAITOK|M_ZERO);
 	strlcpy(ntcc->congctl_name, name, sizeof(ntcc->congctl_name) - 1);
 	ntcc->congctl_ctl = tcc;
 	TAILQ_INSERT_TAIL(&tcp_congctlhd, ntcc, congctl_ent);
 	tcp_congctl_fillnames();
 	if (TAILQ_FIRST(&tcp_congctlhd) == ntcc)
 		tcp_congctl_select(NULL, name);
 	return 0;
+}
 int
 tcp_congctl_unregister(const char *name)
+{
 	struct tcp_congctlent *tccp, *rtccp;
 	unsigned int size;
 	rtccp = NULL;
 	size = 0;
 	TAILQ_FOREACH(tccp, &tcp_congctlhd, congctl_ent) {
 		if (!strcmp(name, tccp->congctl_name))
 			rtccp = tccp;
 		size++;
+	}
 	if (!rtccp)
 		return ENOENT;
 	if (size <= 1 || tcp_congctl_global == rtccp || rtccp->congctl_refcnt)
 		return EBUSY;
 	TAILQ_REMOVE(&tcp_congctlhd, rtccp, congctl_ent);
 	free(rtccp, M_TCPCONGCTL);
 	tcp_congctl_fillnames();
 	return 0;
+}
 /*
  * Select a congestion algorithm by name.
  */
 int
 tcp_congctl_select(struct tcpcb *tp, const char *name)
+{
 	struct tcp_congctlent *tccp, *old_tccp, *new_tccp;
 	bool old_found, new_found;
 	KASSERT(name);
 	old_found = (tp == NULL || tp->t_congctl == NULL);
 	old_tccp = NULL;
 	new_found = false;
 	new_tccp = NULL;
 	TAILQ_FOREACH(tccp, &tcp_congctlhd, congctl_ent) {
 		if (!old_found && tccp->congctl_ctl == tp->t_congctl) {
 			old_tccp = tccp;
 			old_found = true;
+		}
 		if (!new_found && !strcmp(name, tccp->congctl_name)) {
 			new_tccp = tccp;
 			new_found = true;
+		}
 		if (new_found && old_found) {
 			if (tp) {
 				mutex_enter(&tcp_congctl_mtx);
 				if (old_tccp)
 					old_tccp->congctl_refcnt--;
 				tp->t_congctl = new_tccp->congctl_ctl;
 				new_tccp->congctl_refcnt++;
 				mutex_exit(&tcp_congctl_mtx);
 			} else {
 				tcp_congctl_global = new_tccp;
 				strlcpy(tcp_congctl_global_name,
 				    new_tccp->congctl_name,
 				    sizeof(tcp_congctl_global_name) - 1);
+			}
 			return 0;
+		}
+	}
 	return EINVAL;
+}
 void
 tcp_congctl_release(struct tcpcb *tp)
+{
 	struct tcp_congctlent *tccp;
 	KASSERT(tp->t_congctl);
 	TAILQ_FOREACH(tccp, &tcp_congctlhd, congctl_ent) {
 		if (tccp->congctl_ctl == tp->t_congctl) {
 			tccp->congctl_refcnt--;
 			return;
+		}
+	}
+}
 /*
  * Returns the name of a congestion algorithm.
  */
 const char *
 tcp_congctl_bystruct(const struct tcp_congctl *tcc)
+{
 	struct tcp_congctlent *tccp;
 	KASSERT(tcc);
 	TAILQ_FOREACH(tccp, &tcp_congctlhd, congctl_ent)
 		if (tccp->congctl_ctl == tcc)
 			return tccp->congctl_name;
 	return NULL;
+}
 static void
 tcp_congctl_fillnames(void)
+{
 	struct tcp_congctlent *tccp;
 	const char *delim = " ";
 	tcp_congctl_avail[0] = '\0';
 	TAILQ_FOREACH(tccp, &tcp_congctlhd, congctl_ent) {
 		strlcat(tcp_congctl_avail, tccp->congctl_name,
 		    sizeof(tcp_congctl_avail) - 1);
 		if (TAILQ_NEXT(tccp, congctl_ent))
 			strlcat(tcp_congctl_avail, delim,
 			    sizeof(tcp_congctl_avail) - 1);
+	}
+}
 /* ------------------------------------------------------------------------ */
 /*
  * Common stuff
  */
 /* Window reduction (1-beta) for [New]Reno: 0.5 */
 #define RENO_BETAA 1
 #define RENO_BETAB 2
 /* Window reduction (1-beta) for Cubic: 0.8 */
 #define CUBIC_BETAA 4
 #define CUBIC_BETAB 5
 /* Draft Rhee Section 4.1 */
 #define CUBIC_CA 4
 #define CUBIC_CB 10
 static void
 tcp_common_congestion_exp(struct tcpcb *tp, int betaa, int betab)
+{
-	u_int win;
+	u_long win;
 	/*
 	 * Reduce the congestion window and the slow start threshold.
 	 */
-	win = uimin(tp->snd_wnd, tp->snd_cwnd) * betaa / betab / tp->t_segsz;
+	win = ulmin(tp->snd_wnd, tp->snd_cwnd) * betaa / betab / tp->t_segsz;
 	if (win < 2)
 		win = 2;
 	tp->snd_ssthresh = win * tp->t_segsz;
 	tp->snd_recover = tp->snd_max;
 	tp->snd_cwnd = tp->snd_ssthresh;
 	/*
 	 * When using TCP ECN, notify the peer that
 	 * we reduced the cwnd.
 	 */
 	if (TCP_ECN_ALLOWED(tp))
 		tp->t_flags |= TF_ECN_SND_CWR;
+}
 /* ------------------------------------------------------------------------ */
 /*
  * TCP/Reno congestion control.
  */
 static void
 tcp_reno_congestion_exp(struct tcpcb *tp)
+{
 	tcp_common_congestion_exp(tp, RENO_BETAA, RENO_BETAB);
+}
 static int
 tcp_reno_do_fast_retransmit(struct tcpcb *tp, const struct tcphdr *th)
+{
 	/*
 	 * Dup acks mean that packets have left the
 	 * network (they're now cached at the receiver)
 	 * so bump cwnd by the amount in the receiver
 	 * to keep a constant cwnd packets in the
 	 * network.
+	 *
 	 * If we are using TCP/SACK, then enter
 	 * Fast Recovery if the receiver SACKs
 	 * data that is tcprexmtthresh * MSS
 	 * bytes past the last ACKed segment,
 	 * irrespective of the number of DupAcks.
 	 */
 	tcp_seq onxt = tp->snd_nxt;
 	tp->t_partialacks = 0;
 	TCP_TIMER_DISARM(tp, TCPT_REXMT);
 	tp->t_rtttime = 0;
 	if (TCP_SACK_ENABLED(tp)) {
 		tp->t_dupacks = tcprexmtthresh;
 		tp->sack_newdata = tp->snd_nxt;
 		tp->snd_cwnd = tp->t_segsz;
 		(void) tcp_output(tp);
 		return 0;
+	}
 	tp->snd_nxt = th->th_ack;
 	tp->snd_cwnd = tp->t_segsz;
 	(void) tcp_output(tp);
 	tp->snd_cwnd = tp->snd_ssthresh + tp->t_segsz * tp->t_dupacks;
 	if (SEQ_GT(onxt, tp->snd_nxt))
 		tp->snd_nxt = onxt;
 	return 0;
+}
 static int
 tcp_reno_fast_retransmit(struct tcpcb *tp, const struct tcphdr *th)
+{
 	/*
 	 * We know we're losing at the current
 	 * window size so do congestion avoidance
 	 * (set ssthresh to half the current window
 	 * and pull our congestion window back to
 	 * the new ssthresh).
 	 */
 	tcp_reno_congestion_exp(tp);
 	return tcp_reno_do_fast_retransmit(tp, th);
+}
 static void
 tcp_reno_slow_retransmit(struct tcpcb *tp)
+{
-	u_int win;
+	u_long win;
 	/*
 	 * Close the congestion window down to one segment
 	 * (we'll open it by one segment for each ack we get).
 	 * Since we probably have a window's worth of unacked
 	 * data accumulated, this "slow start" keeps us from
 	 * dumping all that data as back-to-back packets (which
 	 * might overwhelm an intermediate gateway).
+	 *
 	 * There are two phases to the opening: Initially we
 	 * open by one mss on each ack.  This makes the window
 	 * size increase exponentially with time.  If the
 	 * window is larger than the path can handle, this
 	 * exponential growth results in dropped packet(s)
 	 * almost immediately.  To get more time between
 	 * drops but still "push" the network to take advantage
 	 * of improving conditions, we switch from exponential
 	 * to linear window opening at some threshhold size.
 	 * For a threshhold, we use half the current window
 	 * size, truncated to a multiple of the mss.
+	 *
 	 * (the minimum cwnd that will give us exponential
 	 * growth is 2 mss.  We don't allow the threshhold
 	 * to go below this.)
 	 */
-	win = uimin(tp->snd_wnd, tp->snd_cwnd) / 2 / tp->t_segsz;
+	win = ulmin(tp->snd_wnd, tp->snd_cwnd) / 2 / tp->t_segsz;
 	if (win < 2)
 		win = 2;
 	/* Loss Window MUST be one segment. */
 	tp->snd_cwnd = tp->t_segsz;
 	tp->snd_ssthresh = win * tp->t_segsz;
 	tp->t_partialacks = -1;
 	tp->t_dupacks = 0;
 	tp->t_bytes_acked = 0;
 	if (TCP_ECN_ALLOWED(tp))
 		tp->t_flags |= TF_ECN_SND_CWR;
+}
 static void
 tcp_reno_fast_retransmit_newack(struct tcpcb *tp,
     const struct tcphdr *th)
+{
 	if (tp->t_partialacks < 0) {
 		/*
 		 * We were not in fast recovery.  Reset the duplicate ack
 		 * counter.
 		 */
 		tp->t_dupacks = 0;
 	} else {
 		/*
 		 * Clamp the congestion window to the crossover point and
 		 * exit fast recovery.
 		 */
 		if (tp->snd_cwnd > tp->snd_ssthresh)
 			tp->snd_cwnd = tp->snd_ssthresh;
 		tp->t_partialacks = -1;
 		tp->t_dupacks = 0;
 		tp->t_bytes_acked = 0;
 		if (TCP_SACK_ENABLED(tp) && SEQ_GT(th->th_ack, tp->snd_fack))
 			tp->snd_fack = th->th_ack;
+	}
+}
 static void
 tcp_reno_newack(struct tcpcb *tp, const struct tcphdr *th)
+{
 	/*
 	 * When new data is acked, open the congestion window.
 	 */
 	u_int cw = tp->snd_cwnd;
 	u_int incr = tp->t_segsz;
 	if (tcp_do_abc) {
 		/*
 		 * RFC 3465 Appropriate Byte Counting (ABC)
 		 */
 		int acked = th->th_ack - tp->snd_una;
 		if (cw >= tp->snd_ssthresh) {
 			tp->t_bytes_acked += acked;
 			if (tp->t_bytes_acked >= cw) {
 				/* Time to increase the window. */
 				tp->t_bytes_acked -= cw;
 			} else {
 				/* No need to increase yet. */
 				incr = 0;
+			}
 		} else {
 			/*
 			 * use 2*SMSS or 1*SMSS for the "L" param,
 			 * depending on sysctl setting.
+			 *
 			 * (See RFC 3465 2.3 Choosing the Limit)
 			 */
 			u_int abc_lim;
 			abc_lim = (tcp_abc_aggressive == 0 ||
 			    tp->snd_nxt != tp->snd_max) ? incr : incr * 2;
 			incr = uimin(acked, abc_lim);
+		}
 	} else {
 		/*
 		 * If the window gives us less than ssthresh packets
 		 * in flight, open exponentially (segsz per packet).
 		 * Otherwise open linearly: segsz per window
 		 * (segsz^2 / cwnd per packet).
 		 */
 		if (cw >= tp->snd_ssthresh) {
 			incr = incr * incr / cw;
+		}
+	}
 	tp->snd_cwnd = uimin(cw + incr, TCP_MAXWIN << tp->snd_scale);
+}
 const struct tcp_congctl tcp_reno_ctl = {
 	.fast_retransmit = tcp_reno_fast_retransmit,
 	.slow_retransmit = tcp_reno_slow_retransmit,
 	.fast_retransmit_newack = tcp_reno_fast_retransmit_newack,
 	.newack = tcp_reno_newack,
 	.cong_exp = tcp_reno_congestion_exp,
 };
 /*
  * TCP/NewReno Congestion control.
  */
 static int
 tcp_newreno_fast_retransmit(struct tcpcb *tp, const struct tcphdr *th)
+{
 	if (SEQ_LT(th->th_ack, tp->snd_high)) {
 		/*
 		 * False fast retransmit after timeout.
 		 * Do not enter fast recovery
 		 */
 		tp->t_dupacks = 0;
 		return 1;
+	}
 	/*
 	 * Fast retransmit is same as reno.
 	 */
 	return tcp_reno_fast_retransmit(tp, th);
+}
 /*
  * Implement the NewReno response to a new ack, checking for partial acks in
  * fast recovery.
  */
 static void
 tcp_newreno_fast_retransmit_newack(struct tcpcb *tp, const struct tcphdr *th)
+{
 	if (tp->t_partialacks < 0) {
 		/*
 		 * We were not in fast recovery.  Reset the duplicate ack
 		 * counter.
 		 */
 		tp->t_dupacks = 0;
 	} else if (SEQ_LT(th->th_ack, tp->snd_recover)) {
 		/*
 		 * This is a partial ack.  Retransmit the first unacknowledged
 		 * segment and deflate the congestion window by the amount of
 		 * acknowledged data.  Do not exit fast recovery.
 		 */
 		tcp_seq onxt = tp->snd_nxt;
 		u_long ocwnd = tp->snd_cwnd;
 		int sack_num_segs = 1, sack_bytes_rxmt = 0;
 		/*
 		 * snd_una has not yet been updated and the socket's send
 		 * buffer has not yet drained off the ACK'd data, so we
 		 * have to leave snd_una as it was to get the correct data
 		 * offset in tcp_output().
 		 */
 		tp->t_partialacks++;
 		TCP_TIMER_DISARM(tp, TCPT_REXMT);
 		tp->t_rtttime = 0;
 		if (TCP_SACK_ENABLED(tp)) {
 			/*
 			 * Partial ack handling within a sack recovery episode.
 			 * Keeping this very simple for now. When a partial ack
 			 * is received, force snd_cwnd to a value that will
 			 * allow the sender to transmit no more than 2 segments.
 			 * If necessary, a fancier scheme can be adopted at a
 			 * later point, but for now, the goal is to prevent the
 			 * sender from bursting a large amount of data in the
 			 * midst of sack recovery.
 		 	 */
 			/*
 			 * send one or 2 segments based on how much
 			 * new data was acked
 			 */
 			if (((th->th_ack - tp->snd_una) / tp->t_segsz) > 2)
 				sack_num_segs = 2;
 			(void)tcp_sack_output(tp, &sack_bytes_rxmt);
 			tp->snd_cwnd = sack_bytes_rxmt +
 			    (tp->snd_nxt - tp->sack_newdata) +
 			    sack_num_segs * tp->t_segsz;
 			tp->t_flags |= TF_ACKNOW;
 			(void) tcp_output(tp);
 		} else {
 			tp->snd_nxt = th->th_ack;
 			/*
 			 * Set snd_cwnd to one segment beyond ACK'd offset
 			 * snd_una is not yet updated when we're called
 			 */
 			tp->snd_cwnd = tp->t_segsz + (th->th_ack - tp->snd_una);
 			(void) tcp_output(tp);
 			tp->snd_cwnd = ocwnd;
 			if (SEQ_GT(onxt, tp->snd_nxt))
 				tp->snd_nxt = onxt;
 			/*
 			 * Partial window deflation.  Relies on fact that
 			 * tp->snd_una not updated yet.
 		 	 */
 			tp->snd_cwnd -= (th->th_ack - tp->snd_una -
 			    tp->t_segsz);
+		}
 	} else {
 		/*
 		 * Complete ack.  Inflate the congestion window to ssthresh
 		 * and exit fast recovery.
+		 *
 		 * Window inflation should have left us with approx.
 		 * snd_ssthresh outstanding data.  But in case we
 		 * would be inclined to send a burst, better to do
 		 * it via the slow start mechanism.
 		 */
 		if (SEQ_SUB(tp->snd_max, th->th_ack) < tp->snd_ssthresh)
 			tp->snd_cwnd = SEQ_SUB(tp->snd_max, th->th_ack)
 			    + tp->t_segsz;
 		else
 			tp->snd_cwnd = tp->snd_ssthresh;
 		tp->t_partialacks = -1;
 		tp->t_dupacks = 0;
 		tp->t_bytes_acked = 0;
 		if (TCP_SACK_ENABLED(tp) && SEQ_GT(th->th_ack, tp->snd_fack))
 			tp->snd_fack = th->th_ack;
+	}
+}
 static void
 tcp_newreno_newack(struct tcpcb *tp, const struct tcphdr *th)
+{
 	/*
 	 * If we are still in fast recovery (meaning we are using
 	 * NewReno and we have only received partial acks), do not
 	 * inflate the window yet.
 	 */
 	if (tp->t_partialacks < 0)
 		tcp_reno_newack(tp, th);
+}
 const struct tcp_congctl tcp_newreno_ctl = {
 	.fast_retransmit = tcp_newreno_fast_retransmit,
 	.slow_retransmit = tcp_reno_slow_retransmit,
 	.fast_retransmit_newack = tcp_newreno_fast_retransmit_newack,
 	.newack = tcp_newreno_newack,
 	.cong_exp = tcp_reno_congestion_exp,
 };
 /*
  * CUBIC - http://tools.ietf.org/html/draft-rhee-tcpm-cubic-02
  */
 /* Cubic prototypes */
 static void	tcp_cubic_update_ctime(struct tcpcb *tp);
 static uint32_t	tcp_cubic_diff_ctime(struct tcpcb *);
 static uint32_t	tcp_cubic_cbrt(uint32_t);
 static ulong	tcp_cubic_getW(struct tcpcb *, uint32_t, uint32_t);
 /* Cubic TIME functions - XXX I don't like using timevals and microuptime */
 /*
  * Set congestion timer to now
  */
 static void
 tcp_cubic_update_ctime(struct tcpcb *tp)
+{
 	struct timeval now_timeval;
 	getmicrouptime(&now_timeval);
 	tp->snd_cubic_ctime = now_timeval.tv_sec * 1000 +
 	    now_timeval.tv_usec / 1000;
+}
 /*
  * miliseconds from last congestion
  */
 static uint32_t
 tcp_cubic_diff_ctime(struct tcpcb *tp)
+{
 	struct timeval now_timeval;
 	getmicrouptime(&now_timeval);
 	return now_timeval.tv_sec * 1000 + now_timeval.tv_usec / 1000 -
 	    tp->snd_cubic_ctime;
+}
 /*
  * Approximate cubic root
  */
 #define CBRT_ROUNDS 30
 static uint32_t
 tcp_cubic_cbrt(uint32_t v)
+{
 	int i, rounds = CBRT_ROUNDS;
 	uint64_t x = v / 3;
 	/* We fail to calculate correct for small numbers */
 	if (v == 0)
 		return 0;
 	else if (v < 4)
 		return 1;
 	/*
 	 * largest x that 2*x^3+3*x fits 64bit
 	 * Avoid overflow for a time cost
 	 */
 	if (x > 2097151)
 		rounds += 10;
 	for (i = 0; i < rounds; i++)
 		if (rounds == CBRT_ROUNDS)
 			x = (v + 2 * x * x * x) / (3 * x * x);
 		else
 			/* Avoid overflow */
 			x = v / (3 * x * x) + 2 * x / 3;
 	return (uint32_t)x;
+}
 /* Draft Rhee Section 3.1 - get W(t+rtt) - Eq. 1 */
 static ulong
 tcp_cubic_getW(struct tcpcb *tp, uint32_t ms_elapsed, uint32_t rtt)
+{
 	uint32_t K;
 	long tK3;
 	/* Section 3.1 Eq. 2 */
 	K = tcp_cubic_cbrt(tp->snd_cubic_wmax / CUBIC_BETAB *
 	    CUBIC_CB / CUBIC_CA);
 	/*  (t-K)^3 - not clear why is the measure unit mattering */
 	tK3 = (long)(ms_elapsed + rtt) - (long)K;
 	tK3 = tK3 * tK3 * tK3;
 	return CUBIC_CA * tK3 / CUBIC_CB + tp->snd_cubic_wmax;
+}
 static void
 tcp_cubic_congestion_exp(struct tcpcb *tp)
+{
 	/*
 	 * Congestion - Set WMax and shrink cwnd
 	 */
 	tcp_cubic_update_ctime(tp);
 	/* Section 3.6 - Fast Convergence */
 	if (tp->snd_cubic_wmax < tp->snd_cubic_wmax_last) {
 		tp->snd_cubic_wmax_last = tp->snd_cubic_wmax;
 		tp->snd_cubic_wmax = tp->snd_cubic_wmax / 2 +
 		    tp->snd_cubic_wmax * CUBIC_BETAA / CUBIC_BETAB / 2;
 	} else {
 		tp->snd_cubic_wmax_last = tp->snd_cubic_wmax;
 		tp->snd_cubic_wmax = tp->snd_cwnd;
+	}
 	tp->snd_cubic_wmax = uimax(tp->t_segsz, tp->snd_cubic_wmax);
 	/* Shrink CWND */
 	tcp_common_congestion_exp(tp, CUBIC_BETAA, CUBIC_BETAB);
+}
 static int
 tcp_cubic_fast_retransmit(struct tcpcb *tp, const struct tcphdr *th)
+{
 	if (SEQ_LT(th->th_ack, tp->snd_high)) {
 		/* See newreno */
 		tp->t_dupacks = 0;
 		return 1;
+	}
 	/*
 	 * mark WMax
 	 */
 	tcp_cubic_congestion_exp(tp);
 	/* Do fast retransmit */
 	return tcp_reno_do_fast_retransmit(tp, th);
+}
 static void
 tcp_cubic_newack(struct tcpcb *tp, const struct tcphdr *th)
+{
 	uint32_t ms_elapsed, rtt;
 	u_long w_tcp;
 	/* Congestion avoidance and not in fast recovery and usable rtt */
 	if (tp->snd_cwnd > tp->snd_ssthresh && tp->t_partialacks < 0 &&
 	    /*
 	     * t_srtt is 1/32 units of slow ticks
 	     * converting it in ms would be equal to
 	     * (t_srtt >> 5) * 1000 / PR_SLOWHZ ~= (t_srtt << 5) / PR_SLOWHZ
 	     */
 	    (rtt = (tp->t_srtt << 5) / PR_SLOWHZ) > 0) {
 		ms_elapsed = tcp_cubic_diff_ctime(tp);
 		/* Compute W_tcp(t) */
 		w_tcp = tp->snd_cubic_wmax * CUBIC_BETAA / CUBIC_BETAB +
 		    ms_elapsed / rtt / 3;
 		if (tp->snd_cwnd > w_tcp) {
 			/* Not in TCP friendly mode */
 			tp->snd_cwnd += (tcp_cubic_getW(tp, ms_elapsed, rtt) -
 			    tp->snd_cwnd) / tp->snd_cwnd;
 		} else {
 			/* friendly TCP mode */
 			tp->snd_cwnd = w_tcp;
+		}
 		/* Make sure we are within limits */
 		tp->snd_cwnd = uimax(tp->snd_cwnd, tp->t_segsz);
 		tp->snd_cwnd = uimin(tp->snd_cwnd, TCP_MAXWIN << tp->snd_scale);
 	} else {
 		/* Use New Reno */
 		tcp_newreno_newack(tp, th);
+	}
+}
 static void
 tcp_cubic_slow_retransmit(struct tcpcb *tp)
+{
 	/* Timeout - Mark new congestion */
 	tcp_cubic_congestion_exp(tp);
 	/* Loss Window MUST be one segment. */
 	tp->snd_cwnd = tp->t_segsz;
 	tp->t_partialacks = -1;
 	tp->t_dupacks = 0;
 	tp->t_bytes_acked = 0;
 	if (TCP_ECN_ALLOWED(tp))
 		tp->t_flags |= TF_ECN_SND_CWR;
+}
 const struct tcp_congctl tcp_cubic_ctl = {
 	.fast_retransmit = tcp_cubic_fast_retransmit,
 	.slow_retransmit = tcp_cubic_slow_retransmit,
 	.fast_retransmit_newack = tcp_newreno_fast_retransmit_newack,
 	.newack = tcp_cubic_newack,
 	.cong_exp = tcp_cubic_congestion_exp,
 };