f3330397f0
happen in the TCP stack, this interface calls the specified callback to
handle the situation according to the currently selected congestion
control algorithm.
A new sysctl node was created: net.inet.tcp.congctl.{available,selected}
with obvious meanings.
The old net.inet.tcp.newreno MIB was removed.
The API is discussed in tcp_congctl(9).
In the near future, it will be possible to selected a congestion control
algorithm on a per-socket basis.
Discussed on tech-net and reviewed by <yamt>.
649 lines
17 KiB
C
649 lines
17 KiB
C
/* $NetBSD: tcp_timer.c,v 1.76 2006/10/09 16:27:07 rpaulo Exp $ */
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/*
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* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
|
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
|
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* notice, this list of conditions and the following disclaimer in the
|
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the project nor the names of its contributors
|
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* may be used to endorse or promote products derived from this software
|
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* without specific prior written permission.
|
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*
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* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
|
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*-
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* Copyright (c) 1997, 1998, 2001, 2005 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe and Kevin M. Lahey of the Numerical Aerospace Simulation
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* Facility, NASA Ames Research Center.
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* This code is derived from software contributed to The NetBSD Foundation
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* by Charles M. Hannum.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
|
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
|
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
|
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* notice, this list of conditions and the following disclaimer.
|
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
|
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* documentation and/or other materials provided with the distribution.
|
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* 3. Neither the name of the University nor the names of its contributors
|
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* may be used to endorse or promote products derived from this software
|
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)tcp_timer.c 8.2 (Berkeley) 5/24/95
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: tcp_timer.c,v 1.76 2006/10/09 16:27:07 rpaulo Exp $");
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#include "opt_inet.h"
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#include "opt_tcp_debug.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/protosw.h>
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#include <sys/errno.h>
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#include <sys/kernel.h>
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#include <net/if.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <netinet/in_pcb.h>
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#include <netinet/ip_var.h>
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#include <netinet/ip_icmp.h>
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#ifdef INET6
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#ifndef INET
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#include <netinet/in.h>
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#endif
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#include <netinet/ip6.h>
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#include <netinet6/in6_pcb.h>
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#endif
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#include <netinet/tcp.h>
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#include <netinet/tcp_fsm.h>
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#include <netinet/tcp_seq.h>
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#include <netinet/tcp_timer.h>
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#include <netinet/tcp_var.h>
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#include <netinet/tcp_congctl.h>
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#include <netinet/tcpip.h>
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#ifdef TCP_DEBUG
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#include <netinet/tcp_debug.h>
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#endif
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/*
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* Various tunable timer parameters. These are initialized in tcp_init(),
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* unless they are patched.
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*/
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int tcp_keepidle = 0;
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int tcp_keepintvl = 0;
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int tcp_keepcnt = 0; /* max idle probes */
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int tcp_maxpersistidle = 0; /* max idle time in persist */
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int tcp_maxidle; /* computed in tcp_slowtimo() */
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/*
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* Time to delay the ACK. This is initialized in tcp_init(), unless
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* its patched.
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*/
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int tcp_delack_ticks = 0;
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void tcp_timer_rexmt(void *);
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void tcp_timer_persist(void *);
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void tcp_timer_keep(void *);
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void tcp_timer_2msl(void *);
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const tcp_timer_func_t tcp_timer_funcs[TCPT_NTIMERS] = {
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tcp_timer_rexmt,
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tcp_timer_persist,
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tcp_timer_keep,
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tcp_timer_2msl,
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};
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/*
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* Timer state initialization, called from tcp_init().
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*/
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void
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tcp_timer_init(void)
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{
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if (tcp_keepidle == 0)
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tcp_keepidle = TCPTV_KEEP_IDLE;
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if (tcp_keepintvl == 0)
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tcp_keepintvl = TCPTV_KEEPINTVL;
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if (tcp_keepcnt == 0)
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tcp_keepcnt = TCPTV_KEEPCNT;
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if (tcp_maxpersistidle == 0)
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tcp_maxpersistidle = TCPTV_KEEP_IDLE;
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if (tcp_delack_ticks == 0)
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tcp_delack_ticks = TCP_DELACK_TICKS;
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}
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/*
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* Return how many timers are currently being invoked.
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*/
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int
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tcp_timers_invoking(struct tcpcb *tp)
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{
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int i;
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int count = 0;
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for (i = 0; i < TCPT_NTIMERS; i++)
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if (callout_invoking(&tp->t_timer[i]))
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count++;
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if (callout_invoking(&tp->t_delack_ch))
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count++;
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return count;
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}
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/*
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* Callout to process delayed ACKs for a TCPCB.
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*/
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void
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tcp_delack(void *arg)
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{
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struct tcpcb *tp = arg;
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int s;
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/*
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* If tcp_output() wasn't able to transmit the ACK
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* for whatever reason, it will restart the delayed
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* ACK callout.
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*/
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s = splsoftnet();
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callout_ack(&tp->t_delack_ch);
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if (tcp_isdead(tp)) {
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splx(s);
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return;
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}
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tp->t_flags |= TF_ACKNOW;
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(void) tcp_output(tp);
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splx(s);
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}
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/*
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* Tcp protocol timeout routine called every 500 ms.
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* Updates the timers in all active tcb's and
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* causes finite state machine actions if timers expire.
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*/
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void
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tcp_slowtimo(void)
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{
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int s;
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s = splsoftnet();
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tcp_maxidle = tcp_keepcnt * tcp_keepintvl;
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tcp_iss_seq += TCP_ISSINCR; /* increment iss */
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tcp_now++; /* for timestamps */
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splx(s);
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}
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/*
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* Cancel all timers for TCP tp.
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*/
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void
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tcp_canceltimers(struct tcpcb *tp)
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{
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int i;
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for (i = 0; i < TCPT_NTIMERS; i++)
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TCP_TIMER_DISARM(tp, i);
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}
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const int tcp_backoff[TCP_MAXRXTSHIFT + 1] =
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{ 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 };
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const int tcp_totbackoff = 511; /* sum of tcp_backoff[] */
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/*
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* TCP timer processing.
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*/
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void
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tcp_timer_rexmt(void *arg)
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{
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struct tcpcb *tp = arg;
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uint32_t rto;
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int s;
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#ifdef TCP_DEBUG
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struct socket *so = NULL;
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short ostate;
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#endif
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s = splsoftnet();
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callout_ack(&tp->t_timer[TCPT_REXMT]);
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if (tcp_isdead(tp)) {
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splx(s);
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return;
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}
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if ((tp->t_flags & TF_PMTUD_PEND) && tp->t_inpcb &&
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SEQ_GEQ(tp->t_pmtud_th_seq, tp->snd_una) &&
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SEQ_LT(tp->t_pmtud_th_seq, (int)(tp->snd_una + tp->t_ourmss))) {
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extern struct sockaddr_in icmpsrc;
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struct icmp icmp;
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tp->t_flags &= ~TF_PMTUD_PEND;
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/* XXX create fake icmp message with relevant entries */
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icmp.icmp_nextmtu = tp->t_pmtud_nextmtu;
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icmp.icmp_ip.ip_len = tp->t_pmtud_ip_len;
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icmp.icmp_ip.ip_hl = tp->t_pmtud_ip_hl;
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icmpsrc.sin_addr = tp->t_inpcb->inp_faddr;
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icmp_mtudisc(&icmp, icmpsrc.sin_addr);
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/*
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* Notify all connections to the same peer about
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* new mss and trigger retransmit.
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*/
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in_pcbnotifyall(&tcbtable, icmpsrc.sin_addr, EMSGSIZE,
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tcp_mtudisc);
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splx(s);
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return;
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}
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#ifdef TCP_DEBUG
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#ifdef INET
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if (tp->t_inpcb)
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so = tp->t_inpcb->inp_socket;
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#endif
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#ifdef INET6
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if (tp->t_in6pcb)
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so = tp->t_in6pcb->in6p_socket;
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#endif
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ostate = tp->t_state;
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#endif /* TCP_DEBUG */
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/*
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* Clear the SACK scoreboard, reset FACK estimate.
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*/
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tcp_free_sackholes(tp);
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tp->snd_fack = tp->snd_una;
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/*
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* Retransmission timer went off. Message has not
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* been acked within retransmit interval. Back off
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* to a longer retransmit interval and retransmit one segment.
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*/
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if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) {
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tp->t_rxtshift = TCP_MAXRXTSHIFT;
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tcpstat.tcps_timeoutdrop++;
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tp = tcp_drop(tp, tp->t_softerror ?
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tp->t_softerror : ETIMEDOUT);
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goto out;
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}
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tcpstat.tcps_rexmttimeo++;
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rto = TCP_REXMTVAL(tp);
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if (rto < tp->t_rttmin)
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rto = tp->t_rttmin;
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TCPT_RANGESET(tp->t_rxtcur, rto * tcp_backoff[tp->t_rxtshift],
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tp->t_rttmin, TCPTV_REXMTMAX);
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TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur);
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/*
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* If we are losing and we are trying path MTU discovery,
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* try turning it off. This will avoid black holes in
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* the network which suppress or fail to send "packet
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* too big" ICMP messages. We should ideally do
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* lots more sophisticated searching to find the right
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* value here...
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*/
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if (tp->t_mtudisc && tp->t_rxtshift > TCP_MAXRXTSHIFT / 6) {
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tcpstat.tcps_pmtublackhole++;
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#ifdef INET
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/* try turning PMTUD off */
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if (tp->t_inpcb)
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tp->t_mtudisc = 0;
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#endif
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#ifdef INET6
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/* try using IPv6 minimum MTU */
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if (tp->t_in6pcb)
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tp->t_mtudisc = 0;
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#endif
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/* XXX: more sophisticated Black hole recovery code? */
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}
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/*
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* If losing, let the lower level know and try for
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* a better route. Also, if we backed off this far,
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* our srtt estimate is probably bogus. Clobber it
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* so we'll take the next rtt measurement as our srtt;
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* move the current srtt into rttvar to keep the current
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* retransmit times until then.
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*/
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if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) {
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#ifdef INET
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if (tp->t_inpcb)
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in_losing(tp->t_inpcb);
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#endif
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#ifdef INET6
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if (tp->t_in6pcb)
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in6_losing(tp->t_in6pcb);
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|
#endif
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tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT);
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tp->t_srtt = 0;
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}
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tp->snd_nxt = tp->snd_una;
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tp->snd_high = tp->snd_max;
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/*
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* If timing a segment in this window, stop the timer.
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*/
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tp->t_rtttime = 0;
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/*
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|
* Remember if we are retransmitting a SYN, because if
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* we do, set the initial congestion window must be set
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* to 1 segment.
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*/
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|
if (tp->t_state == TCPS_SYN_SENT)
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tp->t_flags |= TF_SYN_REXMT;
|
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|
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/*
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|
* Adjust congestion control parameters.
|
|
*/
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|
tp->t_congctl->slow_retransmit(tp);
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|
|
(void) tcp_output(tp);
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|
|
|
out:
|
|
#ifdef TCP_DEBUG
|
|
if (tp && so->so_options & SO_DEBUG)
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|
tcp_trace(TA_USER, ostate, tp, NULL,
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|
PRU_SLOWTIMO | (TCPT_REXMT << 8));
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|
#endif
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|
splx(s);
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|
}
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|
|
void
|
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tcp_timer_persist(void *arg)
|
|
{
|
|
struct tcpcb *tp = arg;
|
|
uint32_t rto;
|
|
int s;
|
|
#ifdef TCP_DEBUG
|
|
struct socket *so = NULL;
|
|
short ostate;
|
|
#endif
|
|
|
|
s = splsoftnet();
|
|
callout_ack(&tp->t_timer[TCPT_PERSIST]);
|
|
if (tcp_isdead(tp)) {
|
|
splx(s);
|
|
return;
|
|
}
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|
|
|
#ifdef TCP_DEBUG
|
|
#ifdef INET
|
|
if (tp->t_inpcb)
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|
so = tp->t_inpcb->inp_socket;
|
|
#endif
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|
#ifdef INET6
|
|
if (tp->t_in6pcb)
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|
so = tp->t_in6pcb->in6p_socket;
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|
#endif
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|
|
ostate = tp->t_state;
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|
#endif /* TCP_DEBUG */
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|
|
/*
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|
* Persistance timer into zero window.
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|
* Force a byte to be output, if possible.
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|
*/
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|
|
/*
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|
* 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.
|
|
*/
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|
rto = TCP_REXMTVAL(tp);
|
|
if (rto < tp->t_rttmin)
|
|
rto = tp->t_rttmin;
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|
if (tp->t_rxtshift == TCP_MAXRXTSHIFT &&
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((tcp_now - tp->t_rcvtime) >= tcp_maxpersistidle ||
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(tcp_now - tp->t_rcvtime) >= rto * tcp_totbackoff)) {
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|
tcpstat.tcps_persistdrops++;
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|
tp = tcp_drop(tp, ETIMEDOUT);
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|
goto out;
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|
}
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|
tcpstat.tcps_persisttimeo++;
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|
tcp_setpersist(tp);
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|
tp->t_force = 1;
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|
(void) tcp_output(tp);
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|
tp->t_force = 0;
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|
|
|
out:
|
|
#ifdef TCP_DEBUG
|
|
if (tp && so->so_options & SO_DEBUG)
|
|
tcp_trace(TA_USER, ostate, tp, NULL,
|
|
PRU_SLOWTIMO | (TCPT_PERSIST << 8));
|
|
#endif
|
|
splx(s);
|
|
}
|
|
|
|
void
|
|
tcp_timer_keep(void *arg)
|
|
{
|
|
struct tcpcb *tp = arg;
|
|
struct socket *so = NULL; /* Quell compiler warning */
|
|
int s;
|
|
#ifdef TCP_DEBUG
|
|
short ostate;
|
|
#endif
|
|
|
|
s = splsoftnet();
|
|
callout_ack(&tp->t_timer[TCPT_KEEP]);
|
|
if (tcp_isdead(tp)) {
|
|
splx(s);
|
|
return;
|
|
}
|
|
|
|
#ifdef TCP_DEBUG
|
|
ostate = tp->t_state;
|
|
#endif /* TCP_DEBUG */
|
|
|
|
/*
|
|
* Keep-alive timer went off; send something
|
|
* or drop connection if idle for too long.
|
|
*/
|
|
|
|
tcpstat.tcps_keeptimeo++;
|
|
if (TCPS_HAVEESTABLISHED(tp->t_state) == 0)
|
|
goto dropit;
|
|
#ifdef INET
|
|
if (tp->t_inpcb)
|
|
so = tp->t_inpcb->inp_socket;
|
|
#endif
|
|
#ifdef INET6
|
|
if (tp->t_in6pcb)
|
|
so = tp->t_in6pcb->in6p_socket;
|
|
#endif
|
|
KASSERT(so != NULL);
|
|
if (so->so_options & SO_KEEPALIVE &&
|
|
tp->t_state <= TCPS_CLOSE_WAIT) {
|
|
if ((tcp_maxidle > 0) &&
|
|
((tcp_now - tp->t_rcvtime) >=
|
|
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++;
|
|
if (tcp_compat_42) {
|
|
/*
|
|
* The keepalive packet must have nonzero
|
|
* length to get a 4.2 host to respond.
|
|
*/
|
|
(void)tcp_respond(tp, tp->t_template,
|
|
(struct mbuf *)NULL, NULL, tp->rcv_nxt - 1,
|
|
tp->snd_una - 1, 0);
|
|
} else {
|
|
(void)tcp_respond(tp, tp->t_template,
|
|
(struct mbuf *)NULL, NULL, tp->rcv_nxt,
|
|
tp->snd_una - 1, 0);
|
|
}
|
|
TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepintvl);
|
|
} else
|
|
TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepidle);
|
|
|
|
#ifdef TCP_DEBUG
|
|
if (tp && so->so_options & SO_DEBUG)
|
|
tcp_trace(TA_USER, ostate, tp, NULL,
|
|
PRU_SLOWTIMO | (TCPT_KEEP << 8));
|
|
#endif
|
|
splx(s);
|
|
return;
|
|
|
|
dropit:
|
|
tcpstat.tcps_keepdrops++;
|
|
(void) tcp_drop(tp, ETIMEDOUT);
|
|
splx(s);
|
|
}
|
|
|
|
void
|
|
tcp_timer_2msl(void *arg)
|
|
{
|
|
struct tcpcb *tp = arg;
|
|
int s;
|
|
#ifdef TCP_DEBUG
|
|
struct socket *so = NULL;
|
|
short ostate;
|
|
#endif
|
|
|
|
s = splsoftnet();
|
|
callout_ack(&tp->t_timer[TCPT_2MSL]);
|
|
if (tcp_isdead(tp)) {
|
|
splx(s);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* 2 MSL timeout went off, clear the SACK scoreboard, reset
|
|
* the FACK estimate.
|
|
*/
|
|
tcp_free_sackholes(tp);
|
|
tp->snd_fack = tp->snd_una;
|
|
|
|
#ifdef TCP_DEBUG
|
|
#ifdef INET
|
|
if (tp->t_inpcb)
|
|
so = tp->t_inpcb->inp_socket;
|
|
#endif
|
|
#ifdef INET6
|
|
if (tp->t_in6pcb)
|
|
so = tp->t_in6pcb->in6p_socket;
|
|
#endif
|
|
|
|
ostate = tp->t_state;
|
|
#endif /* TCP_DEBUG */
|
|
|
|
/*
|
|
* 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 &&
|
|
((tcp_maxidle == 0) || ((tcp_now - tp->t_rcvtime) <= tcp_maxidle)))
|
|
TCP_TIMER_ARM(tp, TCPT_2MSL, tcp_keepintvl);
|
|
else
|
|
tp = tcp_close(tp);
|
|
|
|
#ifdef TCP_DEBUG
|
|
if (tp && so->so_options & SO_DEBUG)
|
|
tcp_trace(TA_USER, ostate, tp, NULL,
|
|
PRU_SLOWTIMO | (TCPT_2MSL << 8));
|
|
#endif
|
|
splx(s);
|
|
}
|