tcp_timer.c

eCos/RedBoot for勤研ARM AnywhereII(4510) 含全部源代码

//==========================================================================
//
//      src/sys/netinet/tcp_timer.c
//
//==========================================================================
//####BSDCOPYRIGHTBEGIN####
//
// -------------------------------------------
//
// Portions of this software may have been derived from OpenBSD, 
// FreeBSD or other sources, and are covered by the appropriate
// copyright disclaimers included herein.
//
// Portions created by Red Hat are
// Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
//
// -------------------------------------------
//
//####BSDCOPYRIGHTEND####
//==========================================================================

/*
 * 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
 * $FreeBSD: src/sys/netinet/tcp_timer.c,v 1.34.2.11 2001/08/22 00:59:12 silby Exp $
 */

#include <sys/param.h>
#include <sys/sysctl.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/protosw.h>

#include <net/route.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_pcb.h>
#ifdef INET6
#include <netinet6/in6_pcb.h>
#endif
#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

#ifdef CYGPKG_NET_FREEBSD_SYSCTL
static int
sysctl_msec_to_ticks(SYSCTL_HANDLER_ARGS)
{
	int error, s, tt;

	tt = *(int *)oidp->oid_arg1;
	s = tt * 1000 / hz;

	error = sysctl_handle_int(oidp, &s, 0, req);
	if (error || !req->newptr)
		return (error);

	tt = s * hz / 1000;
	if (tt < 1)
		return (EINVAL);

	*(int *)oidp->oid_arg1 = tt;
        return (0);
}
static int
sysctl_rexmitmax_rangecheck(SYSCTL_HANDLER_ARGS)
{
	int error, tt;

	tt = *(int *)oidp->oid_arg1;

	error = sysctl_handle_int(oidp, &tt, 0, req);
	if (error || !req->newptr)
		return (error);
		
	if (tt > TCP_MAXRXTSHIFT)
		return (EINVAL);
		
	if (tt < 2)
		return (EINVAL);

	*(int *)oidp->oid_arg1 = tt;
        return (0);
}
#endif
int	tcp_keepinit;
SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINIT, keepinit, CTLTYPE_INT|CTLFLAG_RW,
    &tcp_keepinit, 0, sysctl_msec_to_ticks, "I", "");

int	tcp_keepidle;
SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPIDLE, keepidle, CTLTYPE_INT|CTLFLAG_RW,
    &tcp_keepidle, 0, sysctl_msec_to_ticks, "I", "");

int	tcp_keepintvl;
SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINTVL, keepintvl, CTLTYPE_INT|CTLFLAG_RW,
    &tcp_keepintvl, 0, sysctl_msec_to_ticks, "I", "");

int	tcp_delacktime;
SYSCTL_PROC(_net_inet_tcp, TCPCTL_DELACKTIME, delacktime,
    CTLTYPE_INT|CTLFLAG_RW, &tcp_delacktime, 0, sysctl_msec_to_ticks, "I",
    "Time before a delayed ACK is sent");
 
int	tcp_msl;
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, msl, CTLTYPE_INT|CTLFLAG_RW,
    &tcp_msl, 0, sysctl_msec_to_ticks, "I", "Maximum segment lifetime");

static int	always_keepalive = 0;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, always_keepalive, CTLFLAG_RW, 
    &always_keepalive , 0, "Assume SO_KEEPALIVE on all TCP connections");
    
int	tcp_rexmit_min;
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, rexmit_min, CTLTYPE_INT|CTLFLAG_RW,
    &tcp_rexmit_min, 0, sysctl_msec_to_ticks, "I", "Minimum retransmission timeout");
    
int	tcp_rexmit_shift_max = TCP_MAXRXTSHIFT;
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, rexmit_shift_max, CTLTYPE_INT|CTLFLAG_RW,
    &tcp_rexmit_shift_max, 0, sysctl_rexmitmax_rangecheck, "I", "Maximum TCP retransmissions");    

static int	tcp_keepcnt = TCPTV_KEEPCNT;
	/* max idle probes */
int	tcp_maxpersistidle;
	/* max idle time in persist */
int	tcp_maxidle;

/*
 * Tcp protocol timeout routine called every 500 ms.
 * Updates timestamps used for TCP
 * causes finite state machine actions if timers expire.
 */
void
tcp_slowtimo()
{
	int s;

	s = splnet();

	tcp_maxidle = tcp_keepcnt * tcp_keepintvl;

	splx(s);
}

/*
 * Cancel all timers for TCP tp.
 */
void
tcp_canceltimers(tp)
	struct tcpcb *tp;
{
	callout_stop(tp->tt_2msl);
	callout_stop(tp->tt_persist);
	callout_stop(tp->tt_keep);
	callout_stop(tp->tt_rexmt);
}

int	tcp_syn_backoff[TCP_MAXRXTSHIFT + 1] =
    { 1, 1, 1, 1, 1, 2, 4, 8, 16, 32, 64, 64, 64 };

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.
 */
void
tcp_timer_delack(xtp)
	void *xtp;
{
	struct tcpcb *tp = xtp;
	int s;

	s = splnet();
	if (callout_pending(tp->tt_delack) || !callout_active(tp->tt_delack)) {
		splx(s);
		return;
	}
	callout_deactivate(tp->tt_delack);

	tp->t_flags |= TF_ACKNOW;
	tcpstat.tcps_delack++;
	(void) tcp_output(tp);
	splx(s);
}

void
tcp_timer_2msl(xtp)
	void *xtp;
{
	struct tcpcb *tp = xtp;
	int s;
#ifdef TCPDEBUG
	int ostate;

	ostate = tp->t_state;
#endif
	s = splnet();
	if (callout_pending(tp->tt_2msl) || !callout_active(tp->tt_2msl)) {
		splx(s);
		return;
	}
	callout_deactivate(tp->tt_2msl);
	/*
	 * 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.
	 */
	if (tp->t_state != TCPS_TIME_WAIT &&
	    (ticks - tp->t_rcvtime) <= tcp_maxidle) {
		callout_reset(tp->tt_2msl, tcp_keepintvl,
			      tcp_timer_2msl, tp);
        }
	else {
		tp = tcp_close(tp);
        }

#ifdef TCPDEBUG
	if (tp && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
		tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
			  PRU_SLOWTIMO);
#endif
	splx(s);