603724d3ab
virtualization work done by Marko Zec (zec@). This is the first in a series of commits over the course of the next few weeks. Mark all uses of global variables to be virtualized with a V_ prefix. Use macros to map them back to their global names for now, so this is a NOP change only. We hope to have caught at least 85-90% of what is needed so we do not invalidate a lot of outstanding patches again. Obtained from: //depot/projects/vimage-commit2/... Reviewed by: brooks, des, ed, mav, julian, jamie, kris, rwatson, zec, ... (various people I forgot, different versions) md5 (with a bit of help) Sponsored by: NLnet Foundation, The FreeBSD Foundation X-MFC after: never V_Commit_Message_Reviewed_By: more people than the patch
632 lines
18 KiB
C
632 lines
18 KiB
C
/*-
|
|
* 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.
|
|
* 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
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include "opt_inet6.h"
|
|
#include "opt_tcpdebug.h"
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/lock.h>
|
|
#include <sys/mbuf.h>
|
|
#include <sys/mutex.h>
|
|
#include <sys/protosw.h>
|
|
#include <sys/socket.h>
|
|
#include <sys/socketvar.h>
|
|
#include <sys/sysctl.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/vimage.h>
|
|
|
|
#include <net/route.h>
|
|
|
|
#include <netinet/in.h>
|
|
#include <netinet/in_pcb.h>
|
|
#include <netinet/in_systm.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_timer.h>
|
|
#include <netinet/tcp_var.h>
|
|
#include <netinet/tcpip.h>
|
|
#ifdef TCPDEBUG
|
|
#include <netinet/tcp_debug.h>
|
|
#endif
|
|
|
|
int tcp_keepinit;
|
|
SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINIT, keepinit, CTLTYPE_INT|CTLFLAG_RW,
|
|
&tcp_keepinit, 0, sysctl_msec_to_ticks, "I", "time to establish connection");
|
|
|
|
int tcp_keepidle;
|
|
SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPIDLE, keepidle, CTLTYPE_INT|CTLFLAG_RW,
|
|
&tcp_keepidle, 0, sysctl_msec_to_ticks, "I", "time before keepalive probes begin");
|
|
|
|
int tcp_keepintvl;
|
|
SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINTVL, keepintvl, CTLTYPE_INT|CTLFLAG_RW,
|
|
&tcp_keepintvl, 0, sysctl_msec_to_ticks, "I", "time between keepalive probes");
|
|
|
|
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");
|
|
|
|
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_slop;
|
|
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, rexmit_slop, CTLTYPE_INT|CTLFLAG_RW,
|
|
&tcp_rexmit_slop, 0, sysctl_msec_to_ticks, "I",
|
|
"Retransmission Timer Slop");
|
|
|
|
static int always_keepalive = 1;
|
|
SYSCTL_INT(_net_inet_tcp, OID_AUTO, always_keepalive, CTLFLAG_RW,
|
|
&always_keepalive , 0, "Assume SO_KEEPALIVE on all TCP connections");
|
|
|
|
int tcp_fast_finwait2_recycle = 0;
|
|
SYSCTL_INT(_net_inet_tcp, OID_AUTO, fast_finwait2_recycle, CTLFLAG_RW,
|
|
&tcp_fast_finwait2_recycle, 0,
|
|
"Recycle closed FIN_WAIT_2 connections faster");
|
|
|
|
int tcp_finwait2_timeout;
|
|
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, finwait2_timeout, CTLTYPE_INT|CTLFLAG_RW,
|
|
&tcp_finwait2_timeout, 0, sysctl_msec_to_ticks, "I", "FIN-WAIT2 timeout");
|
|
|
|
|
|
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(void)
|
|
{
|
|
|
|
tcp_maxidle = tcp_keepcnt * tcp_keepintvl;
|
|
INP_INFO_WLOCK(&V_tcbinfo);
|
|
(void) tcp_tw_2msl_scan(0);
|
|
INP_INFO_WUNLOCK(&V_tcbinfo);
|
|
}
|
|
|
|
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, 128, 256, 512, 512, 512, 512 };
|
|
|
|
static int tcp_totbackoff = 2559; /* sum of tcp_backoff[] */
|
|
|
|
static int tcp_timer_race;
|
|
SYSCTL_INT(_net_inet_tcp, OID_AUTO, timer_race, CTLFLAG_RD, &tcp_timer_race,
|
|
0, "Count of t_inpcb races on tcp_discardcb");
|
|
|
|
/*
|
|
* TCP timer processing.
|
|
*/
|
|
|
|
void
|
|
tcp_timer_delack(void *xtp)
|
|
{
|
|
struct tcpcb *tp = xtp;
|
|
struct inpcb *inp;
|
|
|
|
INP_INFO_RLOCK(&V_tcbinfo);
|
|
inp = tp->t_inpcb;
|
|
/*
|
|
* XXXRW: While this assert is in fact correct, bugs in the tcpcb
|
|
* tear-down mean we need it as a work-around for races between
|
|
* timers and tcp_discardcb().
|
|
*
|
|
* KASSERT(inp != NULL, ("tcp_timer_delack: inp == NULL"));
|
|
*/
|
|
if (inp == NULL) {
|
|
tcp_timer_race++;
|
|
INP_INFO_RUNLOCK(&V_tcbinfo);
|
|
return;
|
|
}
|
|
INP_WLOCK(inp);
|
|
INP_INFO_RUNLOCK(&V_tcbinfo);
|
|
if ((inp->inp_vflag & INP_DROPPED) || callout_pending(&tp->t_timers->tt_delack)
|
|
|| !callout_active(&tp->t_timers->tt_delack)) {
|
|
INP_WUNLOCK(inp);
|
|
return;
|
|
}
|
|
callout_deactivate(&tp->t_timers->tt_delack);
|
|
|
|
tp->t_flags |= TF_ACKNOW;
|
|
V_tcpstat.tcps_delack++;
|
|
(void) tcp_output(tp);
|
|
INP_WUNLOCK(inp);
|
|
}
|
|
|
|
void
|
|
tcp_timer_2msl(void *xtp)
|
|
{
|
|
struct tcpcb *tp = xtp;
|
|
struct inpcb *inp;
|
|
#ifdef TCPDEBUG
|
|
int ostate;
|
|
|
|
ostate = tp->t_state;
|
|
#endif
|
|
/*
|
|
* XXXRW: Does this actually happen?
|
|
*/
|
|
INP_INFO_WLOCK(&V_tcbinfo);
|
|
inp = tp->t_inpcb;
|
|
/*
|
|
* XXXRW: While this assert is in fact correct, bugs in the tcpcb
|
|
* tear-down mean we need it as a work-around for races between
|
|
* timers and tcp_discardcb().
|
|
*
|
|
* KASSERT(inp != NULL, ("tcp_timer_2msl: inp == NULL"));
|
|
*/
|
|
if (inp == NULL) {
|
|
tcp_timer_race++;
|
|
INP_INFO_WUNLOCK(&V_tcbinfo);
|
|
return;
|
|
}
|
|
INP_WLOCK(inp);
|
|
tcp_free_sackholes(tp);
|
|
if ((inp->inp_vflag & INP_DROPPED) || callout_pending(&tp->t_timers->tt_2msl) ||
|
|
!callout_active(&tp->t_timers->tt_2msl)) {
|
|
INP_WUNLOCK(tp->t_inpcb);
|
|
INP_INFO_WUNLOCK(&V_tcbinfo);
|
|
return;
|
|
}
|
|
callout_deactivate(&tp->t_timers->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 fastrecycle of FIN_WAIT_2, in FIN_WAIT_2 and receiver has closed,
|
|
* there's no point in hanging onto FIN_WAIT_2 socket. Just close it.
|
|
* Ignore fact that there were recent incoming segments.
|
|
*/
|
|
if (tcp_fast_finwait2_recycle && tp->t_state == TCPS_FIN_WAIT_2 &&
|
|
tp->t_inpcb && tp->t_inpcb->inp_socket &&
|
|
(tp->t_inpcb->inp_socket->so_rcv.sb_state & SBS_CANTRCVMORE)) {
|
|
V_tcpstat.tcps_finwait2_drops++;
|
|
tp = tcp_close(tp);
|
|
} else {
|
|
if (tp->t_state != TCPS_TIME_WAIT &&
|
|
(ticks - tp->t_rcvtime) <= tcp_maxidle)
|
|
callout_reset(&tp->t_timers->tt_2msl, tcp_keepintvl,
|
|
tcp_timer_2msl, tp);
|
|
else
|
|
tp = tcp_close(tp);
|
|
}
|
|
|
|
#ifdef TCPDEBUG
|
|
if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
|
|
tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
|
|
PRU_SLOWTIMO);
|
|
#endif
|
|
if (tp != NULL)
|
|
INP_WUNLOCK(inp);
|
|
INP_INFO_WUNLOCK(&V_tcbinfo);
|
|
}
|
|
|
|
void
|
|
tcp_timer_keep(void *xtp)
|
|
{
|
|
struct tcpcb *tp = xtp;
|
|
struct tcptemp *t_template;
|
|
struct inpcb *inp;
|
|
#ifdef TCPDEBUG
|
|
int ostate;
|
|
|
|
ostate = tp->t_state;
|
|
#endif
|
|
INP_INFO_WLOCK(&V_tcbinfo);
|
|
inp = tp->t_inpcb;
|
|
/*
|
|
* XXXRW: While this assert is in fact correct, bugs in the tcpcb
|
|
* tear-down mean we need it as a work-around for races between
|
|
* timers and tcp_discardcb().
|
|
*
|
|
* KASSERT(inp != NULL, ("tcp_timer_keep: inp == NULL"));
|
|
*/
|
|
if (inp == NULL) {
|
|
tcp_timer_race++;
|
|
INP_INFO_WUNLOCK(&V_tcbinfo);
|
|
return;
|
|
}
|
|
INP_WLOCK(inp);
|
|
if ((inp->inp_vflag & INP_DROPPED) || callout_pending(&tp->t_timers->tt_keep)
|
|
|| !callout_active(&tp->t_timers->tt_keep)) {
|
|
INP_WUNLOCK(inp);
|
|
INP_INFO_WUNLOCK(&V_tcbinfo);
|
|
return;
|
|
}
|
|
callout_deactivate(&tp->t_timers->tt_keep);
|
|
/*
|
|
* Keep-alive timer went off; send something
|
|
* or drop connection if idle for too long.
|
|
*/
|
|
V_tcpstat.tcps_keeptimeo++;
|
|
if (tp->t_state < TCPS_ESTABLISHED)
|
|
goto dropit;
|
|
if ((always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) &&
|
|
tp->t_state <= TCPS_CLOSING) {
|
|
if ((ticks - 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.
|
|
*/
|
|
V_tcpstat.tcps_keepprobe++;
|
|
t_template = tcpip_maketemplate(inp);
|
|
if (t_template) {
|
|
tcp_respond(tp, t_template->tt_ipgen,
|
|
&t_template->tt_t, (struct mbuf *)NULL,
|
|
tp->rcv_nxt, tp->snd_una - 1, 0);
|
|
free(t_template, M_TEMP);
|
|
}
|
|
callout_reset(&tp->t_timers->tt_keep, tcp_keepintvl, tcp_timer_keep, tp);
|
|
} else
|
|
callout_reset(&tp->t_timers->tt_keep, tcp_keepidle, tcp_timer_keep, tp);
|
|
|
|
#ifdef TCPDEBUG
|
|
if (inp->inp_socket->so_options & SO_DEBUG)
|
|
tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
|
|
PRU_SLOWTIMO);
|
|
#endif
|
|
INP_WUNLOCK(inp);
|
|
INP_INFO_WUNLOCK(&V_tcbinfo);
|
|
return;
|
|
|
|
dropit:
|
|
V_tcpstat.tcps_keepdrops++;
|
|
tp = tcp_drop(tp, ETIMEDOUT);
|
|
|
|
#ifdef TCPDEBUG
|
|
if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
|
|
tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
|
|
PRU_SLOWTIMO);
|
|
#endif
|
|
if (tp != NULL)
|
|
INP_WUNLOCK(tp->t_inpcb);
|
|
INP_INFO_WUNLOCK(&V_tcbinfo);
|
|
}
|
|
|
|
void
|
|
tcp_timer_persist(void *xtp)
|
|
{
|
|
struct tcpcb *tp = xtp;
|
|
struct inpcb *inp;
|
|
#ifdef TCPDEBUG
|
|
int ostate;
|
|
|
|
ostate = tp->t_state;
|
|
#endif
|
|
INP_INFO_WLOCK(&V_tcbinfo);
|
|
inp = tp->t_inpcb;
|
|
/*
|
|
* XXXRW: While this assert is in fact correct, bugs in the tcpcb
|
|
* tear-down mean we need it as a work-around for races between
|
|
* timers and tcp_discardcb().
|
|
*
|
|
* KASSERT(inp != NULL, ("tcp_timer_persist: inp == NULL"));
|
|
*/
|
|
if (inp == NULL) {
|
|
tcp_timer_race++;
|
|
INP_INFO_WUNLOCK(&V_tcbinfo);
|
|
return;
|
|
}
|
|
INP_WLOCK(inp);
|
|
if ((inp->inp_vflag & INP_DROPPED) || callout_pending(&tp->t_timers->tt_persist)
|
|
|| !callout_active(&tp->t_timers->tt_persist)) {
|
|
INP_WUNLOCK(inp);
|
|
INP_INFO_WUNLOCK(&V_tcbinfo);
|
|
return;
|
|
}
|
|
callout_deactivate(&tp->t_timers->tt_persist);
|
|
/*
|
|
* Persistance timer into zero window.
|
|
* Force a byte to be output, if possible.
|
|
*/
|
|
V_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 &&
|
|
((ticks - tp->t_rcvtime) >= tcp_maxpersistidle ||
|
|
(ticks - tp->t_rcvtime) >= TCP_REXMTVAL(tp) * tcp_totbackoff)) {
|
|
V_tcpstat.tcps_persistdrop++;
|
|
tp = tcp_drop(tp, ETIMEDOUT);
|
|
goto out;
|
|
}
|
|
tcp_setpersist(tp);
|
|
tp->t_flags |= TF_FORCEDATA;
|
|
(void) tcp_output(tp);
|
|
tp->t_flags &= ~TF_FORCEDATA;
|
|
|
|
out:
|
|
#ifdef TCPDEBUG
|
|
if (tp != NULL && tp->t_inpcb->inp_socket->so_options & SO_DEBUG)
|
|
tcp_trace(TA_USER, ostate, tp, NULL, NULL, PRU_SLOWTIMO);
|
|
#endif
|
|
if (tp != NULL)
|
|
INP_WUNLOCK(inp);
|
|
INP_INFO_WUNLOCK(&V_tcbinfo);
|
|
}
|
|
|
|
void
|
|
tcp_timer_rexmt(void * xtp)
|
|
{
|
|
struct tcpcb *tp = xtp;
|
|
int rexmt;
|
|
int headlocked;
|
|
struct inpcb *inp;
|
|
#ifdef TCPDEBUG
|
|
int ostate;
|
|
|
|
ostate = tp->t_state;
|
|
#endif
|
|
INP_INFO_WLOCK(&V_tcbinfo);
|
|
headlocked = 1;
|
|
inp = tp->t_inpcb;
|
|
/*
|
|
* XXXRW: While this assert is in fact correct, bugs in the tcpcb
|
|
* tear-down mean we need it as a work-around for races between
|
|
* timers and tcp_discardcb().
|
|
*
|
|
* KASSERT(inp != NULL, ("tcp_timer_rexmt: inp == NULL"));
|
|
*/
|
|
if (inp == NULL) {
|
|
tcp_timer_race++;
|
|
INP_INFO_WUNLOCK(&V_tcbinfo);
|
|
return;
|
|
}
|
|
INP_WLOCK(inp);
|
|
if ((inp->inp_vflag & INP_DROPPED) || callout_pending(&tp->t_timers->tt_rexmt)
|
|
|| !callout_active(&tp->t_timers->tt_rexmt)) {
|
|
INP_WUNLOCK(inp);
|
|
INP_INFO_WUNLOCK(&V_tcbinfo);
|
|
return;
|
|
}
|
|
callout_deactivate(&tp->t_timers->tt_rexmt);
|
|
tcp_free_sackholes(tp);
|
|
/*
|
|
* Retransmission timer went off. Message has not
|
|
* been acked within retransmit interval. Back off
|
|
* to a longer retransmit interval and retransmit one segment.
|
|
*/
|
|
if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) {
|
|
tp->t_rxtshift = TCP_MAXRXTSHIFT;
|
|
V_tcpstat.tcps_timeoutdrop++;
|
|
tp = tcp_drop(tp, tp->t_softerror ?
|
|
tp->t_softerror : ETIMEDOUT);
|
|
goto out;
|
|
}
|
|
INP_INFO_WUNLOCK(&V_tcbinfo);
|
|
headlocked = 0;
|
|
if (tp->t_rxtshift == 1) {
|
|
/*
|
|
* first retransmit; record ssthresh and cwnd so they can
|
|
* be recovered if this turns out to be a "bad" retransmit.
|
|
* A retransmit is considered "bad" if an ACK for this
|
|
* segment is received within RTT/2 interval; the assumption
|
|
* here is that the ACK was already in flight. See
|
|
* "On Estimating End-to-End Network Path Properties" by
|
|
* Allman and Paxson for more details.
|
|
*/
|
|
tp->snd_cwnd_prev = tp->snd_cwnd;
|
|
tp->snd_ssthresh_prev = tp->snd_ssthresh;
|
|
tp->snd_recover_prev = tp->snd_recover;
|
|
if (IN_FASTRECOVERY(tp))
|
|
tp->t_flags |= TF_WASFRECOVERY;
|
|
else
|
|
tp->t_flags &= ~TF_WASFRECOVERY;
|
|
tp->t_badrxtwin = ticks + (tp->t_srtt >> (TCP_RTT_SHIFT + 1));
|
|
}
|
|
V_tcpstat.tcps_rexmttimeo++;
|
|
if (tp->t_state == TCPS_SYN_SENT)
|
|
rexmt = TCP_REXMTVAL(tp) * tcp_syn_backoff[tp->t_rxtshift];
|
|
else
|
|
rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift];
|
|
TCPT_RANGESET(tp->t_rxtcur, rexmt,
|
|
tp->t_rttmin, TCPTV_REXMTMAX);
|
|
/*
|
|
* Disable rfc1323 if we havn't got any response to
|
|
* our third SYN to work-around some broken terminal servers
|
|
* (most of which have hopefully been retired) that have bad VJ
|
|
* header compression code which trashes TCP segments containing
|
|
* unknown-to-them TCP options.
|
|
*/
|
|
if ((tp->t_state == TCPS_SYN_SENT) && (tp->t_rxtshift == 3))
|
|
tp->t_flags &= ~(TF_REQ_SCALE|TF_REQ_TSTMP);
|
|
/*
|
|
* 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) {
|
|
#ifdef INET6
|
|
if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0)
|
|
in6_losing(tp->t_inpcb);
|
|
else
|
|
#endif
|
|
tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT);
|
|
tp->t_srtt = 0;
|
|
}
|
|
tp->snd_nxt = tp->snd_una;
|
|
tp->snd_recover = tp->snd_max;
|
|
/*
|
|
* Force a segment to be sent.
|
|
*/
|
|
tp->t_flags |= TF_ACKNOW;
|
|
/*
|
|
* If timing a segment in this window, stop the timer.
|
|
*/
|
|
tp->t_rtttime = 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;
|
|
}
|
|
EXIT_FASTRECOVERY(tp);
|
|
(void) tcp_output(tp);
|
|
|
|
out:
|
|
#ifdef TCPDEBUG
|
|
if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
|
|
tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
|
|
PRU_SLOWTIMO);
|
|
#endif
|
|
if (tp != NULL)
|
|
INP_WUNLOCK(inp);
|
|
if (headlocked)
|
|
INP_INFO_WUNLOCK(&V_tcbinfo);
|
|
}
|
|
|
|
void
|
|
tcp_timer_activate(struct tcpcb *tp, int timer_type, u_int delta)
|
|
{
|
|
struct callout *t_callout;
|
|
void *f_callout;
|
|
|
|
switch (timer_type) {
|
|
case TT_DELACK:
|
|
t_callout = &tp->t_timers->tt_delack;
|
|
f_callout = tcp_timer_delack;
|
|
break;
|
|
case TT_REXMT:
|
|
t_callout = &tp->t_timers->tt_rexmt;
|
|
f_callout = tcp_timer_rexmt;
|
|
break;
|
|
case TT_PERSIST:
|
|
t_callout = &tp->t_timers->tt_persist;
|
|
f_callout = tcp_timer_persist;
|
|
break;
|
|
case TT_KEEP:
|
|
t_callout = &tp->t_timers->tt_keep;
|
|
f_callout = tcp_timer_keep;
|
|
break;
|
|
case TT_2MSL:
|
|
t_callout = &tp->t_timers->tt_2msl;
|
|
f_callout = tcp_timer_2msl;
|
|
break;
|
|
default:
|
|
panic("bad timer_type");
|
|
}
|
|
if (delta == 0) {
|
|
callout_stop(t_callout);
|
|
} else {
|
|
callout_reset(t_callout, delta, f_callout, tp);
|
|
}
|
|
}
|
|
|
|
int
|
|
tcp_timer_active(struct tcpcb *tp, int timer_type)
|
|
{
|
|
struct callout *t_callout;
|
|
|
|
switch (timer_type) {
|
|
case TT_DELACK:
|
|
t_callout = &tp->t_timers->tt_delack;
|
|
break;
|
|
case TT_REXMT:
|
|
t_callout = &tp->t_timers->tt_rexmt;
|
|
break;
|
|
case TT_PERSIST:
|
|
t_callout = &tp->t_timers->tt_persist;
|
|
break;
|
|
case TT_KEEP:
|
|
t_callout = &tp->t_timers->tt_keep;
|
|
break;
|
|
case TT_2MSL:
|
|
t_callout = &tp->t_timers->tt_2msl;
|
|
break;
|
|
default:
|
|
panic("bad timer_type");
|
|
}
|
|
return callout_active(t_callout);
|
|
}
|