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diff --git a/cpukit/libnetworking/netinet/tcp_timer.c b/cpukit/libnetworking/netinet/tcp_timer.c
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+/*
+ * Copyright (c) 1982, 1986, 1988, 1990, 1993, 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. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 4. 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_timer.c 8.2 (Berkeley) 5/24/95
+ * $Id$
+ */
+
+#include "opt_tcpdebug.h"
+
+#ifndef TUBA_INCLUDE
+#include <sys/param.h>
+#include <sys/queue.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/sysctl.h>
+#include <sys/malloc.h>
+#include <sys/mbuf.h>
+#include <sys/socket.h>
+#include <sys/socketvar.h>
+#include <sys/protosw.h>
+#include <sys/errno.h>
+
+#include <machine/cpu.h> /* before tcp_seq.h, for tcp_random18() */
+
+#include <net/if.h>
+#include <net/route.h>
+
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+#include <netinet/in_pcb.h>
+#include <netinet/ip_var.h>
+#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/tcpip.h>
+#ifdef TCPDEBUG
+#include <netinet/tcp_debug.h>
+#endif
+
+int tcp_keepinit = TCPTV_KEEP_INIT;
+SYSCTL_INT(_net_inet_tcp, TCPCTL_KEEPINIT, keepinit,
+ CTLFLAG_RW, &tcp_keepinit , 0, "");
+
+int tcp_keepidle = TCPTV_KEEP_IDLE;
+SYSCTL_INT(_net_inet_tcp, TCPCTL_KEEPIDLE, keepidle,
+ CTLFLAG_RW, &tcp_keepidle , 0, "");
+
+static int tcp_keepintvl = TCPTV_KEEPINTVL;
+SYSCTL_INT(_net_inet_tcp, TCPCTL_KEEPINTVL, keepintvl,
+ CTLFLAG_RW, &tcp_keepintvl , 0, "");
+
+static int always_keepalive = 0;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, always_keepalive,
+ CTLFLAG_RW, &always_keepalive , 0, "");
+
+static int tcp_keepcnt = TCPTV_KEEPCNT;
+ /* max idle probes */
+static int tcp_maxpersistidle = TCPTV_KEEP_IDLE;
+ /* max idle time in persist */
+int tcp_maxidle;
+#else /* TUBA_INCLUDE */
+
+static int tcp_maxpersistidle;
+#endif /* TUBA_INCLUDE */
+
+/*
+ * Fast timeout routine for processing delayed acks
+ */
+void
+tcp_fasttimo()
+{
+ register struct inpcb *inp;
+ register struct tcpcb *tp;
+ int s;
+
+ s = splnet();
+
+ for (inp = tcb.lh_first; inp != NULL; inp = inp->inp_list.le_next) {
+ if ((tp = (struct tcpcb *)inp->inp_ppcb) &&
+ (tp->t_flags & TF_DELACK)) {
+ tp->t_flags &= ~TF_DELACK;
+ tp->t_flags |= TF_ACKNOW;
+ tcpstat.tcps_delack++;
+ (void) tcp_output(tp);
+ }
+ }
+ splx(s);
+}
+
+/*
+ * Tcp protocol timeout routine called every 500 ms.
+ * Updates the timers in all active tcb's and
+ * causes finite state machine actions if timers expire.
+ */
+void
+tcp_slowtimo()
+{
+ register struct inpcb *ip, *ipnxt;
+ register struct tcpcb *tp;
+ register int i;
+ int s;
+#ifdef TCPDEBUG
+ int ostate;
+#endif
+
+ s = splnet();
+
+ tcp_maxidle = tcp_keepcnt * tcp_keepintvl;
+
+ ip = tcb.lh_first;
+ if (ip == NULL) {
+ splx(s);
+ return;
+ }
+ /*
+ * Search through tcb's and update active timers.
+ */
+ for (; ip != NULL; ip = ipnxt) {
+ ipnxt = ip->inp_list.le_next;
+ tp = intotcpcb(ip);
+ if (tp == 0 || tp->t_state == TCPS_LISTEN)
+ continue;
+ for (i = 0; i < TCPT_NTIMERS; i++) {
+ if (tp->t_timer[i] && --tp->t_timer[i] == 0) {
+#ifdef TCPDEBUG
+ ostate = tp->t_state;
+#endif
+ tp = tcp_timers(tp, i);
+ if (tp == NULL)
+ goto tpgone;
+#ifdef TCPDEBUG
+ if (tp->t_inpcb->inp_socket->so_options
+ & SO_DEBUG)
+ tcp_trace(TA_USER, ostate, tp,
+ (struct tcpiphdr *)0,
+ PRU_SLOWTIMO);
+#endif
+ }
+ }
+ tp->t_idle++;
+ tp->t_duration++;
+ if (tp->t_rtt)
+ tp->t_rtt++;
+tpgone:
+ ;
+ }
+ tcp_iss += TCP_ISSINCR/PR_SLOWHZ; /* increment iss */
+#ifdef TCP_COMPAT_42
+ if ((int)tcp_iss < 0)
+ tcp_iss = TCP_ISSINCR; /* XXX */
+#endif
+ tcp_now++; /* for timestamps */
+ splx(s);
+}
+#ifndef TUBA_INCLUDE
+
+/*
+ * Cancel all timers for TCP tp.
+ */
+void
+tcp_canceltimers(tp)
+ struct tcpcb *tp;
+{
+ register int i;
+
+ for (i = 0; i < TCPT_NTIMERS; i++)
+ tp->t_timer[i] = 0;
+}
+
+int tcp_backoff[TCP_MAXRXTSHIFT + 1] =
+ { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 };
+
+static int tcp_totbackoff = 511; /* sum of tcp_backoff[] */
+
+/*
+ * TCP timer processing.
+ */
+struct tcpcb *
+tcp_timers(tp, timer)
+ register struct tcpcb *tp;
+ int timer;
+{
+ register int rexmt;
+
+ switch (timer) {
+
+ /*
+ * 2 MSL timeout in shutdown went off. If we're closed but
+ * still waiting for peer to close and connection has been idle
+ * too long, or if 2MSL time is up from TIME_WAIT, delete connection
+ * control block. Otherwise, check again in a bit.
+ */
+ case TCPT_2MSL:
+ if (tp->t_state != TCPS_TIME_WAIT &&
+ tp->t_idle <= tcp_maxidle)
+ tp->t_timer[TCPT_2MSL] = tcp_keepintvl;
+ else
+ tp = tcp_close(tp);
+ break;
+
+ /*
+ * Retransmission timer went off. Message has not
+ * been acked within retransmit interval. Back off
+ * to a longer retransmit interval and retransmit one segment.
+ */
+ case TCPT_REXMT:
+ if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) {
+ tp->t_rxtshift = TCP_MAXRXTSHIFT;
+ tcpstat.tcps_timeoutdrop++;
+ tp = tcp_drop(tp, tp->t_softerror ?
+ tp->t_softerror : ETIMEDOUT);
+ break;
+ }
+ tcpstat.tcps_rexmttimeo++;
+ rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift];
+ TCPT_RANGESET(tp->t_rxtcur, rexmt,
+ tp->t_rttmin, TCPTV_REXMTMAX);
+ tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
+ /*
+ * If losing, let the lower level know and try for
+ * a better route. Also, if we backed off this far,
+ * our srtt estimate is probably bogus. Clobber it
+ * so we'll take the next rtt measurement as our srtt;
+ * move the current srtt into rttvar to keep the current
+ * retransmit times until then.
+ */
+ if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) {
+ in_losing(tp->t_inpcb);
+ tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT);
+ tp->t_srtt = 0;
+ }
+ tp->snd_nxt = tp->snd_una;
+ /*
+ * Force a segment to be sent.
+ */
+ tp->t_flags |= TF_ACKNOW;
+ /*
+ * If timing a segment in this window, stop the timer.
+ */
+ tp->t_rtt = 0;
+ /*
+ * 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.)
+ */
+ {
+ u_int win = min(tp->snd_wnd, tp->snd_cwnd) / 2 / tp->t_maxseg;
+ if (win < 2)
+ win = 2;
+ tp->snd_cwnd = tp->t_maxseg;
+ tp->snd_ssthresh = win * tp->t_maxseg;
+ tp->t_dupacks = 0;
+ }
+ (void) tcp_output(tp);
+ break;
+
+ /*
+ * Persistance timer into zero window.
+ * Force a byte to be output, if possible.
+ */
+ case TCPT_PERSIST:
+ tcpstat.tcps_persisttimeo++;
+ /*
+ * Hack: if the peer is dead/unreachable, we do not
+ * time out if the window is closed. After a full
+ * backoff, drop the connection if the idle time
+ * (no responses to probes) reaches the maximum
+ * backoff that we would use if retransmitting.
+ */
+ if (tp->t_rxtshift == TCP_MAXRXTSHIFT) {
+ u_long maxidle = TCP_REXMTVAL(tp);
+ if (maxidle < tp->t_rttmin)
+ maxidle = tp->t_rttmin;
+ maxidle *= tcp_totbackoff;
+ if (tp->t_idle >= tcp_maxpersistidle ||
+ tp->t_idle >= maxidle) {
+ tcpstat.tcps_persistdrop++;
+ tp = tcp_drop(tp, ETIMEDOUT);
+ break;
+ }
+ }
+ tcp_setpersist(tp);
+ tp->t_force = 1;
+ (void) tcp_output(tp);
+ tp->t_force = 0;
+ break;
+
+ /*
+ * Keep-alive timer went off; send something
+ * or drop connection if idle for too long.
+ */
+ case TCPT_KEEP:
+ tcpstat.tcps_keeptimeo++;
+ if (tp->t_state < TCPS_ESTABLISHED)
+ goto dropit;
+ if ((always_keepalive ||
+ tp->t_inpcb->inp_socket->so_options & SO_KEEPALIVE) &&
+ tp->t_state <= TCPS_CLOSING) {
+ if (tp->t_idle >= tcp_keepidle + tcp_maxidle)
+ goto dropit;
+ /*
+ * Send a packet designed to force a response
+ * if the peer is up and reachable:
+ * either an ACK if the connection is still alive,
+ * or an RST if the peer has closed the connection
+ * due to timeout or reboot.
+ * Using sequence number tp->snd_una-1
+ * causes the transmitted zero-length segment
+ * to lie outside the receive window;
+ * by the protocol spec, this requires the
+ * correspondent TCP to respond.
+ */
+ tcpstat.tcps_keepprobe++;
+#ifdef TCP_COMPAT_42
+ /*
+ * The keepalive packet must have nonzero length
+ * to get a 4.2 host to respond.
+ */
+ tcp_respond(tp, tp->t_template, (struct mbuf *)NULL,
+ tp->rcv_nxt - 1, tp->snd_una - 1, 0);
+#else
+ tcp_respond(tp, tp->t_template, (struct mbuf *)NULL,
+ tp->rcv_nxt, tp->snd_una - 1, 0);
+#endif
+ tp->t_timer[TCPT_KEEP] = tcp_keepintvl;
+ } else
+ tp->t_timer[TCPT_KEEP] = tcp_keepidle;
+ break;
+ dropit:
+ tcpstat.tcps_keepdrops++;
+ tp = tcp_drop(tp, ETIMEDOUT);
+ break;
+ }
+ return (tp);
+}
+#endif /* TUBA_INCLUDE */