The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/netinet/tcp_timer.c

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * SPDX-License-Identifier: BSD-3-Clause
    3  *
    4  * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
    5  *      The Regents of the University of California.  All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  * 3. Neither the name of the University nor the names of its contributors
   16  *    may be used to endorse or promote products derived from this software
   17  *    without specific prior written permission.
   18  *
   19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   29  * SUCH DAMAGE.
   30  *
   31  *      @(#)tcp_timer.c 8.2 (Berkeley) 5/24/95
   32  */
   33 
   34 #include <sys/cdefs.h>
   35 __FBSDID("$FreeBSD$");
   36 
   37 #include "opt_inet.h"
   38 #include "opt_inet6.h"
   39 #include "opt_tcpdebug.h"
   40 #include "opt_rss.h"
   41 
   42 #include <sys/param.h>
   43 #include <sys/kernel.h>
   44 #include <sys/lock.h>
   45 #include <sys/mbuf.h>
   46 #include <sys/mutex.h>
   47 #include <sys/protosw.h>
   48 #include <sys/smp.h>
   49 #include <sys/socket.h>
   50 #include <sys/socketvar.h>
   51 #include <sys/sysctl.h>
   52 #include <sys/systm.h>
   53 
   54 #include <net/if.h>
   55 #include <net/route.h>
   56 #include <net/rss_config.h>
   57 #include <net/vnet.h>
   58 #include <net/netisr.h>
   59 
   60 #include <netinet/in.h>
   61 #include <netinet/in_kdtrace.h>
   62 #include <netinet/in_pcb.h>
   63 #include <netinet/in_rss.h>
   64 #include <netinet/in_systm.h>
   65 #ifdef INET6
   66 #include <netinet6/in6_pcb.h>
   67 #endif
   68 #include <netinet/ip_var.h>
   69 #include <netinet/tcp.h>
   70 #include <netinet/tcp_fsm.h>
   71 #include <netinet/tcp_log_buf.h>
   72 #include <netinet/tcp_timer.h>
   73 #include <netinet/tcp_var.h>
   74 #include <netinet/tcp_seq.h>
   75 #include <netinet/cc/cc.h>
   76 #ifdef INET6
   77 #include <netinet6/tcp6_var.h>
   78 #endif
   79 #include <netinet/tcpip.h>
   80 #ifdef TCPDEBUG
   81 #include <netinet/tcp_debug.h>
   82 #endif
   83 
   84 int    tcp_persmin;
   85 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, persmin, CTLTYPE_INT|CTLFLAG_RW,
   86     &tcp_persmin, 0, sysctl_msec_to_ticks, "I", "minimum persistence interval");
   87 
   88 int    tcp_persmax;
   89 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, persmax, CTLTYPE_INT|CTLFLAG_RW,
   90     &tcp_persmax, 0, sysctl_msec_to_ticks, "I", "maximum persistence interval");
   91 
   92 int     tcp_keepinit;
   93 SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINIT, keepinit, CTLTYPE_INT|CTLFLAG_RW,
   94     &tcp_keepinit, 0, sysctl_msec_to_ticks, "I", "time to establish connection");
   95 
   96 int     tcp_keepidle;
   97 SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPIDLE, keepidle, CTLTYPE_INT|CTLFLAG_RW,
   98     &tcp_keepidle, 0, sysctl_msec_to_ticks, "I", "time before keepalive probes begin");
   99 
  100 int     tcp_keepintvl;
  101 SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINTVL, keepintvl, CTLTYPE_INT|CTLFLAG_RW,
  102     &tcp_keepintvl, 0, sysctl_msec_to_ticks, "I", "time between keepalive probes");
  103 
  104 int     tcp_delacktime;
  105 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DELACKTIME, delacktime, CTLTYPE_INT|CTLFLAG_RW,
  106     &tcp_delacktime, 0, sysctl_msec_to_ticks, "I",
  107     "Time before a delayed ACK is sent");
  108 
  109 int     tcp_msl;
  110 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, msl, CTLTYPE_INT|CTLFLAG_RW,
  111     &tcp_msl, 0, sysctl_msec_to_ticks, "I", "Maximum segment lifetime");
  112 
  113 int     tcp_rexmit_initial;
  114 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, rexmit_initial, CTLTYPE_INT|CTLFLAG_RW,
  115     &tcp_rexmit_initial, 0, sysctl_msec_to_ticks, "I",
  116     "Initial Retransmission Timeout");
  117 
  118 int     tcp_rexmit_min;
  119 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, rexmit_min, CTLTYPE_INT|CTLFLAG_RW,
  120     &tcp_rexmit_min, 0, sysctl_msec_to_ticks, "I",
  121     "Minimum Retransmission Timeout");
  122 
  123 int     tcp_rexmit_slop;
  124 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, rexmit_slop, CTLTYPE_INT|CTLFLAG_RW,
  125     &tcp_rexmit_slop, 0, sysctl_msec_to_ticks, "I",
  126     "Retransmission Timer Slop");
  127 
  128 VNET_DEFINE(int, tcp_always_keepalive) = 1;
  129 SYSCTL_INT(_net_inet_tcp, OID_AUTO, always_keepalive, CTLFLAG_VNET|CTLFLAG_RW,
  130     &VNET_NAME(tcp_always_keepalive) , 0,
  131     "Assume SO_KEEPALIVE on all TCP connections");
  132 
  133 int    tcp_fast_finwait2_recycle = 0;
  134 SYSCTL_INT(_net_inet_tcp, OID_AUTO, fast_finwait2_recycle, CTLFLAG_RW, 
  135     &tcp_fast_finwait2_recycle, 0,
  136     "Recycle closed FIN_WAIT_2 connections faster");
  137 
  138 int    tcp_finwait2_timeout;
  139 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, finwait2_timeout, CTLTYPE_INT|CTLFLAG_RW,
  140     &tcp_finwait2_timeout, 0, sysctl_msec_to_ticks, "I", "FIN-WAIT2 timeout");
  141 
  142 int     tcp_keepcnt = TCPTV_KEEPCNT;
  143 SYSCTL_INT(_net_inet_tcp, OID_AUTO, keepcnt, CTLFLAG_RW, &tcp_keepcnt, 0,
  144     "Number of keepalive probes to send");
  145 
  146         /* max idle probes */
  147 int     tcp_maxpersistidle;
  148 
  149 int     tcp_rexmit_drop_options = 0;
  150 SYSCTL_INT(_net_inet_tcp, OID_AUTO, rexmit_drop_options, CTLFLAG_RW,
  151     &tcp_rexmit_drop_options, 0,
  152     "Drop TCP options from 3rd and later retransmitted SYN");
  153 
  154 VNET_DEFINE(int, tcp_pmtud_blackhole_detect);
  155 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pmtud_blackhole_detection,
  156     CTLFLAG_RW|CTLFLAG_VNET,
  157     &VNET_NAME(tcp_pmtud_blackhole_detect), 0,
  158     "Path MTU Discovery Black Hole Detection Enabled");
  159 
  160 #ifdef INET
  161 VNET_DEFINE(int, tcp_pmtud_blackhole_mss) = 1200;
  162 SYSCTL_INT(_net_inet_tcp, OID_AUTO, pmtud_blackhole_mss,
  163     CTLFLAG_RW|CTLFLAG_VNET,
  164     &VNET_NAME(tcp_pmtud_blackhole_mss), 0,
  165     "Path MTU Discovery Black Hole Detection lowered MSS");
  166 #endif
  167 
  168 #ifdef INET6
  169 VNET_DEFINE(int, tcp_v6pmtud_blackhole_mss) = 1220;
  170 SYSCTL_INT(_net_inet_tcp, OID_AUTO, v6pmtud_blackhole_mss,
  171     CTLFLAG_RW|CTLFLAG_VNET,
  172     &VNET_NAME(tcp_v6pmtud_blackhole_mss), 0,
  173     "Path MTU Discovery IPv6 Black Hole Detection lowered MSS");
  174 #endif
  175 
  176 #ifdef  RSS
  177 static int      per_cpu_timers = 1;
  178 #else
  179 static int      per_cpu_timers = 0;
  180 #endif
  181 SYSCTL_INT(_net_inet_tcp, OID_AUTO, per_cpu_timers, CTLFLAG_RW,
  182     &per_cpu_timers , 0, "run tcp timers on all cpus");
  183 
  184 /*
  185  * Map the given inp to a CPU id.
  186  *
  187  * This queries RSS if it's compiled in, else it defaults to the current
  188  * CPU ID.
  189  */
  190 inline int
  191 inp_to_cpuid(struct inpcb *inp)
  192 {
  193         u_int cpuid;
  194 
  195 #ifdef  RSS
  196         if (per_cpu_timers) {
  197                 cpuid = rss_hash2cpuid(inp->inp_flowid, inp->inp_flowtype);
  198                 if (cpuid == NETISR_CPUID_NONE)
  199                         return (curcpu);        /* XXX */
  200                 else
  201                         return (cpuid);
  202         }
  203 #else
  204         /* Legacy, pre-RSS behaviour */
  205         if (per_cpu_timers) {
  206                 /*
  207                  * We don't have a flowid -> cpuid mapping, so cheat and
  208                  * just map unknown cpuids to curcpu.  Not the best, but
  209                  * apparently better than defaulting to swi 0.
  210                  */
  211                 cpuid = inp->inp_flowid % (mp_maxid + 1);
  212                 if (! CPU_ABSENT(cpuid))
  213                         return (cpuid);
  214                 return (curcpu);
  215         }
  216 #endif
  217         /* Default for RSS and non-RSS - cpuid 0 */
  218         else {
  219                 return (0);
  220         }
  221 }
  222 
  223 /*
  224  * Tcp protocol timeout routine called every 500 ms.
  225  * Updates timestamps used for TCP
  226  * causes finite state machine actions if timers expire.
  227  */
  228 void
  229 tcp_slowtimo(void)
  230 {
  231         VNET_ITERATOR_DECL(vnet_iter);
  232 
  233         VNET_LIST_RLOCK_NOSLEEP();
  234         VNET_FOREACH(vnet_iter) {
  235                 CURVNET_SET(vnet_iter);
  236                 (void) tcp_tw_2msl_scan(0);
  237                 CURVNET_RESTORE();
  238         }
  239         VNET_LIST_RUNLOCK_NOSLEEP();
  240 }
  241 
  242 int     tcp_backoff[TCP_MAXRXTSHIFT + 1] =
  243     { 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 512, 512, 512 };
  244 
  245 int tcp_totbackoff = 2559;      /* sum of tcp_backoff[] */
  246 
  247 /*
  248  * TCP timer processing.
  249  */
  250 
  251 void
  252 tcp_timer_delack(void *xtp)
  253 {
  254         struct tcpcb *tp = xtp;
  255         struct inpcb *inp;
  256         CURVNET_SET(tp->t_vnet);
  257 
  258         inp = tp->t_inpcb;
  259         KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
  260         INP_WLOCK(inp);
  261         if (callout_pending(&tp->t_timers->tt_delack) ||
  262             !callout_active(&tp->t_timers->tt_delack)) {
  263                 INP_WUNLOCK(inp);
  264                 CURVNET_RESTORE();
  265                 return;
  266         }
  267         callout_deactivate(&tp->t_timers->tt_delack);
  268         if ((inp->inp_flags & INP_DROPPED) != 0) {
  269                 INP_WUNLOCK(inp);
  270                 CURVNET_RESTORE();
  271                 return;
  272         }
  273         tp->t_flags |= TF_ACKNOW;
  274         TCPSTAT_INC(tcps_delack);
  275         (void) tp->t_fb->tfb_tcp_output(tp);
  276         INP_WUNLOCK(inp);
  277         CURVNET_RESTORE();
  278 }
  279 
  280 void
  281 tcp_inpinfo_lock_del(struct inpcb *inp, struct tcpcb *tp)
  282 {
  283         if (inp && tp != NULL)
  284                 INP_WUNLOCK(inp);
  285 }
  286 
  287 void
  288 tcp_timer_2msl(void *xtp)
  289 {
  290         struct tcpcb *tp = xtp;
  291         struct inpcb *inp;
  292         struct epoch_tracker et;
  293         CURVNET_SET(tp->t_vnet);
  294 #ifdef TCPDEBUG
  295         int ostate;
  296 
  297         ostate = tp->t_state;
  298 #endif
  299         inp = tp->t_inpcb;
  300         KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
  301         INP_WLOCK(inp);
  302         tcp_free_sackholes(tp);
  303         if (callout_pending(&tp->t_timers->tt_2msl) ||
  304             !callout_active(&tp->t_timers->tt_2msl)) {
  305                 INP_WUNLOCK(tp->t_inpcb);
  306                 CURVNET_RESTORE();
  307                 return;
  308         }
  309         callout_deactivate(&tp->t_timers->tt_2msl);
  310         if ((inp->inp_flags & INP_DROPPED) != 0) {
  311                 INP_WUNLOCK(inp);
  312                 CURVNET_RESTORE();
  313                 return;
  314         }
  315         KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0,
  316                 ("%s: tp %p tcpcb can't be stopped here", __func__, tp));
  317         /*
  318          * 2 MSL timeout in shutdown went off.  If we're closed but
  319          * still waiting for peer to close and connection has been idle
  320          * too long delete connection control block.  Otherwise, check
  321          * again in a bit.
  322          *
  323          * If in TIME_WAIT state just ignore as this timeout is handled in
  324          * tcp_tw_2msl_scan().
  325          *
  326          * If fastrecycle of FIN_WAIT_2, in FIN_WAIT_2 and receiver has closed, 
  327          * there's no point in hanging onto FIN_WAIT_2 socket. Just close it. 
  328          * Ignore fact that there were recent incoming segments.
  329          */
  330         if ((inp->inp_flags & INP_TIMEWAIT) != 0) {
  331                 INP_WUNLOCK(inp);
  332                 CURVNET_RESTORE();
  333                 return;
  334         }
  335         if (tcp_fast_finwait2_recycle && tp->t_state == TCPS_FIN_WAIT_2 &&
  336             tp->t_inpcb && tp->t_inpcb->inp_socket && 
  337             (tp->t_inpcb->inp_socket->so_rcv.sb_state & SBS_CANTRCVMORE)) {
  338                 TCPSTAT_INC(tcps_finwait2_drops);
  339                 if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
  340                         tcp_inpinfo_lock_del(inp, tp);
  341                         goto out;
  342                 }
  343                 INP_INFO_RLOCK_ET(&V_tcbinfo, et);
  344                 tp = tcp_close(tp);             
  345                 INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
  346                 tcp_inpinfo_lock_del(inp, tp);
  347                 goto out;
  348         } else {
  349                 if (ticks - tp->t_rcvtime <= TP_MAXIDLE(tp)) {
  350                         callout_reset(&tp->t_timers->tt_2msl,
  351                                       TP_KEEPINTVL(tp), tcp_timer_2msl, tp);
  352                 } else {
  353                         if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
  354                                 tcp_inpinfo_lock_del(inp, tp);
  355                                 goto out;
  356                         }
  357                         INP_INFO_RLOCK_ET(&V_tcbinfo, et);
  358                         tp = tcp_close(tp);
  359                         INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
  360                         tcp_inpinfo_lock_del(inp, tp);
  361                         goto out;
  362                 }
  363         }
  364 
  365 #ifdef TCPDEBUG
  366         if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
  367                 tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
  368                           PRU_SLOWTIMO);
  369 #endif
  370         TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO);
  371 
  372         if (tp != NULL)
  373                 INP_WUNLOCK(inp);
  374 out:
  375         CURVNET_RESTORE();
  376 }
  377 
  378 void
  379 tcp_timer_keep(void *xtp)
  380 {
  381         struct tcpcb *tp = xtp;
  382         struct tcptemp *t_template;
  383         struct inpcb *inp;
  384         struct epoch_tracker et;
  385         CURVNET_SET(tp->t_vnet);
  386 #ifdef TCPDEBUG
  387         int ostate;
  388 
  389         ostate = tp->t_state;
  390 #endif
  391         inp = tp->t_inpcb;
  392         KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
  393         INP_WLOCK(inp);
  394         if (callout_pending(&tp->t_timers->tt_keep) ||
  395             !callout_active(&tp->t_timers->tt_keep)) {
  396                 INP_WUNLOCK(inp);
  397                 CURVNET_RESTORE();
  398                 return;
  399         }
  400         callout_deactivate(&tp->t_timers->tt_keep);
  401         if ((inp->inp_flags & INP_DROPPED) != 0) {
  402                 INP_WUNLOCK(inp);
  403                 CURVNET_RESTORE();
  404                 return;
  405         }
  406         KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0,
  407                 ("%s: tp %p tcpcb can't be stopped here", __func__, tp));
  408 
  409         /*
  410          * Because we don't regularly reset the keepalive callout in
  411          * the ESTABLISHED state, it may be that we don't actually need
  412          * to send a keepalive yet. If that occurs, schedule another
  413          * call for the next time the keepalive timer might expire.
  414          */
  415         if (TCPS_HAVEESTABLISHED(tp->t_state)) {
  416                 u_int idletime;
  417 
  418                 idletime = ticks - tp->t_rcvtime;
  419                 if (idletime < TP_KEEPIDLE(tp)) {
  420                         callout_reset(&tp->t_timers->tt_keep,
  421                             TP_KEEPIDLE(tp) - idletime, tcp_timer_keep, tp);
  422                         INP_WUNLOCK(inp);
  423                         CURVNET_RESTORE();
  424                         return;
  425                 }
  426         }
  427 
  428         /*
  429          * Keep-alive timer went off; send something
  430          * or drop connection if idle for too long.
  431          */
  432         TCPSTAT_INC(tcps_keeptimeo);
  433         if (tp->t_state < TCPS_ESTABLISHED)
  434                 goto dropit;
  435         if ((V_tcp_always_keepalive ||
  436             inp->inp_socket->so_options & SO_KEEPALIVE) &&
  437             tp->t_state <= TCPS_CLOSING) {
  438                 if (ticks - tp->t_rcvtime >= TP_KEEPIDLE(tp) + TP_MAXIDLE(tp))
  439                         goto dropit;
  440                 /*
  441                  * Send a packet designed to force a response
  442                  * if the peer is up and reachable:
  443                  * either an ACK if the connection is still alive,
  444                  * or an RST if the peer has closed the connection
  445                  * due to timeout or reboot.
  446                  * Using sequence number tp->snd_una-1
  447                  * causes the transmitted zero-length segment
  448                  * to lie outside the receive window;
  449                  * by the protocol spec, this requires the
  450                  * correspondent TCP to respond.
  451                  */
  452                 TCPSTAT_INC(tcps_keepprobe);
  453                 t_template = tcpip_maketemplate(inp);
  454                 if (t_template) {
  455                         tcp_respond(tp, t_template->tt_ipgen,
  456                                     &t_template->tt_t, (struct mbuf *)NULL,
  457                                     tp->rcv_nxt, tp->snd_una - 1, 0);
  458                         free(t_template, M_TEMP);
  459                 }
  460                 callout_reset(&tp->t_timers->tt_keep, TP_KEEPINTVL(tp),
  461                               tcp_timer_keep, tp);
  462         } else
  463                 callout_reset(&tp->t_timers->tt_keep, TP_KEEPIDLE(tp),
  464                               tcp_timer_keep, tp);
  465 
  466 #ifdef TCPDEBUG
  467         if (inp->inp_socket->so_options & SO_DEBUG)
  468                 tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
  469                           PRU_SLOWTIMO);
  470 #endif
  471         TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO);
  472         INP_WUNLOCK(inp);
  473         CURVNET_RESTORE();
  474         return;
  475 
  476 dropit:
  477         TCPSTAT_INC(tcps_keepdrops);
  478         if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
  479                 tcp_inpinfo_lock_del(inp, tp);
  480                 goto out;
  481         }
  482         INP_INFO_RLOCK_ET(&V_tcbinfo, et);
  483         tp = tcp_drop(tp, ETIMEDOUT);
  484 
  485 #ifdef TCPDEBUG
  486         if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
  487                 tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
  488                           PRU_SLOWTIMO);
  489 #endif
  490         TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO);
  491         INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
  492         tcp_inpinfo_lock_del(inp, tp);
  493  out:
  494         CURVNET_RESTORE();
  495 }
  496 
  497 void
  498 tcp_timer_persist(void *xtp)
  499 {
  500         struct tcpcb *tp = xtp;
  501         struct inpcb *inp;
  502         struct epoch_tracker et;
  503         CURVNET_SET(tp->t_vnet);
  504 #ifdef TCPDEBUG
  505         int ostate;
  506 
  507         ostate = tp->t_state;
  508 #endif
  509         inp = tp->t_inpcb;
  510         KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
  511         INP_WLOCK(inp);
  512         if (callout_pending(&tp->t_timers->tt_persist) ||
  513             !callout_active(&tp->t_timers->tt_persist)) {
  514                 INP_WUNLOCK(inp);
  515                 CURVNET_RESTORE();
  516                 return;
  517         }
  518         callout_deactivate(&tp->t_timers->tt_persist);
  519         if ((inp->inp_flags & INP_DROPPED) != 0) {
  520                 INP_WUNLOCK(inp);
  521                 CURVNET_RESTORE();
  522                 return;
  523         }
  524         KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0,
  525                 ("%s: tp %p tcpcb can't be stopped here", __func__, tp));
  526         /*
  527          * Persistence timer into zero window.
  528          * Force a byte to be output, if possible.
  529          */
  530         TCPSTAT_INC(tcps_persisttimeo);
  531         /*
  532          * Hack: if the peer is dead/unreachable, we do not
  533          * time out if the window is closed.  After a full
  534          * backoff, drop the connection if the idle time
  535          * (no responses to probes) reaches the maximum
  536          * backoff that we would use if retransmitting.
  537          */
  538         if (tp->t_rxtshift == TCP_MAXRXTSHIFT &&
  539             (ticks - tp->t_rcvtime >= tcp_maxpersistidle ||
  540              ticks - tp->t_rcvtime >= TCP_REXMTVAL(tp) * tcp_totbackoff)) {
  541                 TCPSTAT_INC(tcps_persistdrop);
  542                 if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
  543                         tcp_inpinfo_lock_del(inp, tp);
  544                         goto out;
  545                 }
  546                 INP_INFO_RLOCK_ET(&V_tcbinfo, et);
  547                 tp = tcp_drop(tp, ETIMEDOUT);
  548                 INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
  549                 tcp_inpinfo_lock_del(inp, tp);
  550                 goto out;
  551         }
  552         /*
  553          * If the user has closed the socket then drop a persisting
  554          * connection after a much reduced timeout.
  555          */
  556         if (tp->t_state > TCPS_CLOSE_WAIT &&
  557             (ticks - tp->t_rcvtime) >= TCPTV_PERSMAX) {
  558                 TCPSTAT_INC(tcps_persistdrop);
  559                 if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
  560                         tcp_inpinfo_lock_del(inp, tp);
  561                         goto out;
  562                 }
  563                 INP_INFO_RLOCK_ET(&V_tcbinfo, et);
  564                 tp = tcp_drop(tp, ETIMEDOUT);
  565                 INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
  566                 tcp_inpinfo_lock_del(inp, tp);
  567                 goto out;
  568         }
  569         tcp_setpersist(tp);
  570         tp->t_flags |= TF_FORCEDATA;
  571         (void) tp->t_fb->tfb_tcp_output(tp);
  572         tp->t_flags &= ~TF_FORCEDATA;
  573 
  574 #ifdef TCPDEBUG
  575         if (tp != NULL && tp->t_inpcb->inp_socket->so_options & SO_DEBUG)
  576                 tcp_trace(TA_USER, ostate, tp, NULL, NULL, PRU_SLOWTIMO);
  577 #endif
  578         TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO);
  579         INP_WUNLOCK(inp);
  580 out:
  581         CURVNET_RESTORE();
  582 }
  583 
  584 void
  585 tcp_timer_rexmt(void * xtp)
  586 {
  587         struct tcpcb *tp = xtp;
  588         CURVNET_SET(tp->t_vnet);
  589         int rexmt;
  590         struct inpcb *inp;
  591         struct epoch_tracker et;
  592         bool isipv6;
  593 #ifdef TCPDEBUG
  594         int ostate;
  595 
  596         ostate = tp->t_state;
  597 #endif
  598         inp = tp->t_inpcb;
  599         KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
  600         INP_WLOCK(inp);
  601         if (callout_pending(&tp->t_timers->tt_rexmt) ||
  602             !callout_active(&tp->t_timers->tt_rexmt)) {
  603                 INP_WUNLOCK(inp);
  604                 CURVNET_RESTORE();
  605                 return;
  606         }
  607         callout_deactivate(&tp->t_timers->tt_rexmt);
  608         if ((inp->inp_flags & INP_DROPPED) != 0) {
  609                 INP_WUNLOCK(inp);
  610                 CURVNET_RESTORE();
  611                 return;
  612         }
  613         KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0,
  614                 ("%s: tp %p tcpcb can't be stopped here", __func__, tp));
  615         tcp_free_sackholes(tp);
  616         TCP_LOG_EVENT(tp, NULL, NULL, NULL, TCP_LOG_RTO, 0, 0, NULL, false);
  617         if (tp->t_fb->tfb_tcp_rexmit_tmr) {
  618                 /* The stack has a timer action too. */
  619                 (*tp->t_fb->tfb_tcp_rexmit_tmr)(tp);
  620         }
  621         /*
  622          * Retransmission timer went off.  Message has not
  623          * been acked within retransmit interval.  Back off
  624          * to a longer retransmit interval and retransmit one segment.
  625          */
  626         if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) {
  627                 tp->t_rxtshift = TCP_MAXRXTSHIFT;
  628                 TCPSTAT_INC(tcps_timeoutdrop);
  629                 if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
  630                         tcp_inpinfo_lock_del(inp, tp);
  631                         goto out;
  632                 }
  633                 INP_INFO_RLOCK_ET(&V_tcbinfo, et);
  634                 tp = tcp_drop(tp, ETIMEDOUT);
  635                 INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
  636                 tcp_inpinfo_lock_del(inp, tp);
  637                 goto out;
  638         }
  639         if (tp->t_state == TCPS_SYN_SENT) {
  640                 /*
  641                  * If the SYN was retransmitted, indicate CWND to be
  642                  * limited to 1 segment in cc_conn_init().
  643                  */
  644                 tp->snd_cwnd = 1;
  645         } else if (tp->t_rxtshift == 1) {
  646                 /*
  647                  * first retransmit; record ssthresh and cwnd so they can
  648                  * be recovered if this turns out to be a "bad" retransmit.
  649                  * A retransmit is considered "bad" if an ACK for this
  650                  * segment is received within RTT/2 interval; the assumption
  651                  * here is that the ACK was already in flight.  See
  652                  * "On Estimating End-to-End Network Path Properties" by
  653                  * Allman and Paxson for more details.
  654                  */
  655                 tp->snd_cwnd_prev = tp->snd_cwnd;
  656                 tp->snd_ssthresh_prev = tp->snd_ssthresh;
  657                 tp->snd_recover_prev = tp->snd_recover;
  658                 if (IN_FASTRECOVERY(tp->t_flags))
  659                         tp->t_flags |= TF_WASFRECOVERY;
  660                 else
  661                         tp->t_flags &= ~TF_WASFRECOVERY;
  662                 if (IN_CONGRECOVERY(tp->t_flags))
  663                         tp->t_flags |= TF_WASCRECOVERY;
  664                 else
  665                         tp->t_flags &= ~TF_WASCRECOVERY;
  666                 if ((tp->t_flags & TF_RCVD_TSTMP) == 0)
  667                         tp->t_badrxtwin = ticks + (tp->t_srtt >> (TCP_RTT_SHIFT + 1));
  668                 /* In the event that we've negotiated timestamps
  669                  * badrxtwin will be set to the value that we set
  670                  * the retransmitted packet's to_tsval to by tcp_output
  671                  */
  672                 tp->t_flags |= TF_PREVVALID;
  673         } else
  674                 tp->t_flags &= ~TF_PREVVALID;
  675         TCPSTAT_INC(tcps_rexmttimeo);
  676         if ((tp->t_state == TCPS_SYN_SENT) ||
  677             (tp->t_state == TCPS_SYN_RECEIVED))
  678                 rexmt = tcp_rexmit_initial * tcp_backoff[tp->t_rxtshift];
  679         else
  680                 rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift];
  681         TCPT_RANGESET(tp->t_rxtcur, rexmt,
  682                       tp->t_rttmin, TCPTV_REXMTMAX);
  683 
  684         /*
  685          * We enter the path for PLMTUD if connection is established or, if
  686          * connection is FIN_WAIT_1 status, reason for the last is that if
  687          * amount of data we send is very small, we could send it in couple of
  688          * packets and process straight to FIN. In that case we won't catch
  689          * ESTABLISHED state.
  690          */
  691 #ifdef INET6
  692         isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) ? true : false;
  693 #else
  694         isipv6 = false;
  695 #endif
  696         if (((V_tcp_pmtud_blackhole_detect == 1) ||
  697             (V_tcp_pmtud_blackhole_detect == 2 && !isipv6) ||
  698             (V_tcp_pmtud_blackhole_detect == 3 && isipv6)) &&
  699             ((tp->t_state == TCPS_ESTABLISHED) ||
  700             (tp->t_state == TCPS_FIN_WAIT_1))) {
  701                 if (tp->t_rxtshift == 1) {
  702                         /*
  703                          * We enter blackhole detection after the first
  704                          * unsuccessful timer based retransmission.
  705                          * Then we reduce up to two times the MSS, each
  706                          * candidate giving two tries of retransmissions.
  707                          * But we give a candidate only two tries, if it
  708                          * actually reduces the MSS.
  709                          */
  710                         tp->t_blackhole_enter = 2;
  711                         tp->t_blackhole_exit = tp->t_blackhole_enter;
  712                         if (isipv6) {
  713 #ifdef INET6
  714                                 if (tp->t_maxseg > V_tcp_v6pmtud_blackhole_mss)
  715                                         tp->t_blackhole_exit += 2;
  716                                 if (tp->t_maxseg > V_tcp_v6mssdflt &&
  717                                     V_tcp_v6pmtud_blackhole_mss > V_tcp_v6mssdflt)
  718                                         tp->t_blackhole_exit += 2;
  719 #endif
  720                         } else {
  721 #ifdef INET
  722                                 if (tp->t_maxseg > V_tcp_pmtud_blackhole_mss)
  723                                         tp->t_blackhole_exit += 2;
  724                                 if (tp->t_maxseg > V_tcp_mssdflt &&
  725                                     V_tcp_pmtud_blackhole_mss > V_tcp_mssdflt)
  726                                         tp->t_blackhole_exit += 2;
  727 #endif
  728                         }
  729                 }
  730                 if (((tp->t_flags2 & (TF2_PLPMTU_PMTUD|TF2_PLPMTU_MAXSEGSNT)) ==
  731                     (TF2_PLPMTU_PMTUD|TF2_PLPMTU_MAXSEGSNT)) &&
  732                     (tp->t_rxtshift >= tp->t_blackhole_enter &&
  733                     tp->t_rxtshift < tp->t_blackhole_exit &&
  734                     (tp->t_rxtshift - tp->t_blackhole_enter) % 2 == 0)) {
  735                         /*
  736                          * Enter Path MTU Black-hole Detection mechanism:
  737                          * - Disable Path MTU Discovery (IP "DF" bit).
  738                          * - Reduce MTU to lower value than what we
  739                          *   negotiated with peer.
  740                          */
  741                         if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) == 0) {
  742                                 /* Record that we may have found a black hole. */
  743                                 tp->t_flags2 |= TF2_PLPMTU_BLACKHOLE;
  744                                 /* Keep track of previous MSS. */
  745                                 tp->t_pmtud_saved_maxseg = tp->t_maxseg;
  746                         }
  747 
  748                         /* 
  749                          * Reduce the MSS to blackhole value or to the default
  750                          * in an attempt to retransmit.
  751                          */
  752 #ifdef INET6
  753                         if (isipv6 &&
  754                             tp->t_maxseg > V_tcp_v6pmtud_blackhole_mss &&
  755                             V_tcp_v6pmtud_blackhole_mss > V_tcp_v6mssdflt) {
  756                                 /* Use the sysctl tuneable blackhole MSS. */
  757                                 tp->t_maxseg = V_tcp_v6pmtud_blackhole_mss;
  758                                 TCPSTAT_INC(tcps_pmtud_blackhole_activated);
  759                         } else if (isipv6) {
  760                                 /* Use the default MSS. */
  761                                 tp->t_maxseg = V_tcp_v6mssdflt;
  762                                 /*
  763                                  * Disable Path MTU Discovery when we switch to
  764                                  * minmss.
  765                                  */
  766                                 tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
  767                                 TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss);
  768                         }
  769 #endif
  770 #if defined(INET6) && defined(INET)
  771                         else
  772 #endif
  773 #ifdef INET
  774                         if (tp->t_maxseg > V_tcp_pmtud_blackhole_mss &&
  775                             V_tcp_pmtud_blackhole_mss > V_tcp_mssdflt) {
  776                                 /* Use the sysctl tuneable blackhole MSS. */
  777                                 tp->t_maxseg = V_tcp_pmtud_blackhole_mss;
  778                                 TCPSTAT_INC(tcps_pmtud_blackhole_activated);
  779                         } else {
  780                                 /* Use the default MSS. */
  781                                 tp->t_maxseg = V_tcp_mssdflt;
  782                                 /*
  783                                  * Disable Path MTU Discovery when we switch to
  784                                  * minmss.
  785                                  */
  786                                 tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
  787                                 TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss);
  788                         }
  789 #endif
  790                         /*
  791                          * Reset the slow-start flight size
  792                          * as it may depend on the new MSS.
  793                          */
  794                         if (CC_ALGO(tp)->conn_init != NULL)
  795                                 CC_ALGO(tp)->conn_init(tp->ccv);
  796                 } else {
  797                         /*
  798                          * If further retransmissions are still unsuccessful
  799                          * with a lowered MTU, maybe this isn't a blackhole and
  800                          * we restore the previous MSS and blackhole detection
  801                          * flags.
  802                          */
  803                         if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) &&
  804                             (tp->t_rxtshift >= tp->t_blackhole_exit)) {
  805                                 tp->t_flags2 |= TF2_PLPMTU_PMTUD;
  806                                 tp->t_flags2 &= ~TF2_PLPMTU_BLACKHOLE;
  807                                 tp->t_maxseg = tp->t_pmtud_saved_maxseg;
  808                                 TCPSTAT_INC(tcps_pmtud_blackhole_failed);
  809                                 /*
  810                                  * Reset the slow-start flight size as it
  811                                  * may depend on the new MSS.
  812                                  */
  813                                 if (CC_ALGO(tp)->conn_init != NULL)
  814                                         CC_ALGO(tp)->conn_init(tp->ccv);
  815                         }
  816                 }
  817         }
  818 
  819         /*
  820          * Disable RFC1323 and SACK if we haven't got any response to
  821          * our third SYN to work-around some broken terminal servers
  822          * (most of which have hopefully been retired) that have bad VJ
  823          * header compression code which trashes TCP segments containing
  824          * unknown-to-them TCP options.
  825          */
  826         if (tcp_rexmit_drop_options && (tp->t_state == TCPS_SYN_SENT) &&
  827             (tp->t_rxtshift == 3))
  828                 tp->t_flags &= ~(TF_REQ_SCALE|TF_REQ_TSTMP|TF_SACK_PERMIT);
  829         /*
  830          * If we backed off this far, notify the L3 protocol that we're having
  831          * connection problems.
  832          */
  833         if (tp->t_rxtshift > TCP_RTT_INVALIDATE) {
  834 #ifdef INET6
  835                 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0)
  836                         in6_losing(tp->t_inpcb);
  837                 else
  838 #endif
  839                         in_losing(tp->t_inpcb);
  840         }
  841         tp->snd_nxt = tp->snd_una;
  842         tp->snd_recover = tp->snd_max;
  843         /*
  844          * Force a segment to be sent.
  845          */
  846         tp->t_flags |= TF_ACKNOW;
  847         /*
  848          * If timing a segment in this window, stop the timer.
  849          */
  850         tp->t_rtttime = 0;
  851 
  852         cc_cong_signal(tp, NULL, CC_RTO);
  853 
  854         (void) tp->t_fb->tfb_tcp_output(tp);
  855 
  856 #ifdef TCPDEBUG
  857         if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
  858                 tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
  859                           PRU_SLOWTIMO);
  860 #endif
  861         TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO);
  862         INP_WUNLOCK(inp);
  863 out:
  864         CURVNET_RESTORE();
  865 }
  866 
  867 void
  868 tcp_timer_activate(struct tcpcb *tp, uint32_t timer_type, u_int delta)
  869 {
  870         struct callout *t_callout;
  871         timeout_t *f_callout;
  872         struct inpcb *inp = tp->t_inpcb;
  873         int cpu = inp_to_cpuid(inp);
  874 
  875 #ifdef TCP_OFFLOAD
  876         if (tp->t_flags & TF_TOE)
  877                 return;
  878 #endif
  879 
  880         if (tp->t_timers->tt_flags & TT_STOPPED)
  881                 return;
  882 
  883         switch (timer_type) {
  884                 case TT_DELACK:
  885                         t_callout = &tp->t_timers->tt_delack;
  886                         f_callout = tcp_timer_delack;
  887                         break;
  888                 case TT_REXMT:
  889                         t_callout = &tp->t_timers->tt_rexmt;
  890                         f_callout = tcp_timer_rexmt;
  891                         break;
  892                 case TT_PERSIST:
  893                         t_callout = &tp->t_timers->tt_persist;
  894                         f_callout = tcp_timer_persist;
  895                         break;
  896                 case TT_KEEP:
  897                         t_callout = &tp->t_timers->tt_keep;
  898                         f_callout = tcp_timer_keep;
  899                         break;
  900                 case TT_2MSL:
  901                         t_callout = &tp->t_timers->tt_2msl;
  902                         f_callout = tcp_timer_2msl;
  903                         break;
  904                 default:
  905                         if (tp->t_fb->tfb_tcp_timer_activate) {
  906                                 tp->t_fb->tfb_tcp_timer_activate(tp, timer_type, delta);
  907                                 return;
  908                         }
  909                         panic("tp %p bad timer_type %#x", tp, timer_type);
  910                 }
  911         if (delta == 0) {
  912                 callout_stop(t_callout);
  913         } else {
  914                 callout_reset_on(t_callout, delta, f_callout, tp, cpu);
  915         }
  916 }
  917 
  918 int
  919 tcp_timer_active(struct tcpcb *tp, uint32_t timer_type)
  920 {
  921         struct callout *t_callout;
  922 
  923         switch (timer_type) {
  924                 case TT_DELACK:
  925                         t_callout = &tp->t_timers->tt_delack;
  926                         break;
  927                 case TT_REXMT:
  928                         t_callout = &tp->t_timers->tt_rexmt;
  929                         break;
  930                 case TT_PERSIST:
  931                         t_callout = &tp->t_timers->tt_persist;
  932                         break;
  933                 case TT_KEEP:
  934                         t_callout = &tp->t_timers->tt_keep;
  935                         break;
  936                 case TT_2MSL:
  937                         t_callout = &tp->t_timers->tt_2msl;
  938                         break;
  939                 default:
  940                         if (tp->t_fb->tfb_tcp_timer_active) {
  941                                 return(tp->t_fb->tfb_tcp_timer_active(tp, timer_type));
  942                         }
  943                         panic("tp %p bad timer_type %#x", tp, timer_type);
  944                 }
  945         return callout_active(t_callout);
  946 }
  947 
  948 /*
  949  * Stop the timer from running, and apply a flag
  950  * against the timer_flags that will force the
  951  * timer never to run. The flag is needed to assure
  952  * a race does not leave it running and cause
  953  * the timer to possibly restart itself (keep and persist
  954  * especially do this). 
  955  */
  956 int
  957 tcp_timer_suspend(struct tcpcb *tp, uint32_t timer_type)
  958 {
  959         struct callout *t_callout;
  960         uint32_t t_flags;
  961 
  962         switch (timer_type) {
  963                 case TT_DELACK:
  964                         t_flags = TT_DELACK_SUS;
  965                         t_callout = &tp->t_timers->tt_delack;
  966                         break;
  967                 case TT_REXMT:
  968                         t_flags = TT_REXMT_SUS;
  969                         t_callout = &tp->t_timers->tt_rexmt;
  970                         break;
  971                 case TT_PERSIST:
  972                         t_flags = TT_PERSIST_SUS;
  973                         t_callout = &tp->t_timers->tt_persist;
  974                         break;
  975                 case TT_KEEP:
  976                         t_flags = TT_KEEP_SUS;
  977                         t_callout = &tp->t_timers->tt_keep;
  978                         break;
  979                 case TT_2MSL:
  980                         t_flags = TT_2MSL_SUS;
  981                         t_callout = &tp->t_timers->tt_2msl;
  982                         break;
  983                 default:
  984                         panic("tp:%p bad timer_type 0x%x", tp, timer_type);
  985         }
  986         tp->t_timers->tt_flags |= t_flags;
  987         return (callout_stop(t_callout));
  988 }
  989 
  990 void
  991 tcp_timers_unsuspend(struct tcpcb *tp, uint32_t timer_type)
  992 {
  993         switch (timer_type) {
  994                 case TT_DELACK:
  995                         if (tp->t_timers->tt_flags & TT_DELACK_SUS) {
  996                                 tp->t_timers->tt_flags &= ~TT_DELACK_SUS;
  997                                 if (tp->t_flags & TF_DELACK) {
  998                                         /* Delayed ack timer should be up activate a timer */
  999                                         tp->t_flags &= ~TF_DELACK;
 1000                                         tcp_timer_activate(tp, TT_DELACK,
 1001                                             tcp_delacktime);
 1002                                 }
 1003                         }
 1004                         break;
 1005                 case TT_REXMT:
 1006                         if (tp->t_timers->tt_flags & TT_REXMT_SUS) {
 1007                                 tp->t_timers->tt_flags &= ~TT_REXMT_SUS;
 1008                                 if (SEQ_GT(tp->snd_max, tp->snd_una) &&
 1009                                     (tcp_timer_active((tp), TT_PERSIST) == 0) &&
 1010                                     tp->snd_wnd) {
 1011                                         /* We have outstanding data activate a timer */
 1012                                         tcp_timer_activate(tp, TT_REXMT, 
 1013                                             tp->t_rxtcur);
 1014                                 }
 1015                         }
 1016                         break;
 1017                 case TT_PERSIST:
 1018                         if (tp->t_timers->tt_flags & TT_PERSIST_SUS) {
 1019                                 tp->t_timers->tt_flags &= ~TT_PERSIST_SUS;
 1020                                 if (tp->snd_wnd == 0) {
 1021                                         /* Activate the persists timer */
 1022                                         tp->t_rxtshift = 0;
 1023                                         tcp_setpersist(tp);
 1024                                 }
 1025                         }
 1026                         break;
 1027                 case TT_KEEP:
 1028                         if (tp->t_timers->tt_flags & TT_KEEP_SUS) {
 1029                                 tp->t_timers->tt_flags &= ~TT_KEEP_SUS;
 1030                                 tcp_timer_activate(tp, TT_KEEP,
 1031                                             TCPS_HAVEESTABLISHED(tp->t_state) ?
 1032                                             TP_KEEPIDLE(tp) : TP_KEEPINIT(tp));
 1033                         }
 1034                         break;
 1035                 case TT_2MSL:
 1036                         if (tp->t_timers->tt_flags &= TT_2MSL_SUS) {
 1037                                 tp->t_timers->tt_flags &= ~TT_2MSL_SUS;
 1038                                 if ((tp->t_state == TCPS_FIN_WAIT_2) &&
 1039                                     ((tp->t_inpcb->inp_socket == NULL) ||
 1040                                      (tp->t_inpcb->inp_socket->so_rcv.sb_state & SBS_CANTRCVMORE))) {
 1041                                         /* Star the 2MSL timer */
 1042                                         tcp_timer_activate(tp, TT_2MSL,
 1043                                             (tcp_fast_finwait2_recycle) ?
 1044                                             tcp_finwait2_timeout : TP_MAXIDLE(tp));
 1045                                 }
 1046                         }
 1047                         break;
 1048                 default:
 1049                         panic("tp:%p bad timer_type 0x%x", tp, timer_type);
 1050         }
 1051 }
 1052 
 1053 void
 1054 tcp_timer_stop(struct tcpcb *tp, uint32_t timer_type)
 1055 {
 1056         struct callout *t_callout;
 1057 
 1058         tp->t_timers->tt_flags |= TT_STOPPED;
 1059         switch (timer_type) {
 1060                 case TT_DELACK:
 1061                         t_callout = &tp->t_timers->tt_delack;
 1062                         break;
 1063                 case TT_REXMT:
 1064                         t_callout = &tp->t_timers->tt_rexmt;
 1065                         break;
 1066                 case TT_PERSIST:
 1067                         t_callout = &tp->t_timers->tt_persist;
 1068                         break;
 1069                 case TT_KEEP:
 1070                         t_callout = &tp->t_timers->tt_keep;
 1071                         break;
 1072                 case TT_2MSL:
 1073                         t_callout = &tp->t_timers->tt_2msl;
 1074                         break;
 1075                 default:
 1076                         if (tp->t_fb->tfb_tcp_timer_stop) {
 1077                                 /* 
 1078                                  * XXXrrs we need to look at this with the
 1079                                  * stop case below (flags).
 1080                                  */
 1081                                 tp->t_fb->tfb_tcp_timer_stop(tp, timer_type);
 1082                                 return;
 1083                         }
 1084                         panic("tp %p bad timer_type %#x", tp, timer_type);
 1085                 }
 1086 
 1087         if (callout_async_drain(t_callout, tcp_timer_discard) == 0) {
 1088                 /*
 1089                  * Can't stop the callout, defer tcpcb actual deletion
 1090                  * to the last one. We do this using the async drain
 1091                  * function and incrementing the count in 
 1092                  */
 1093                 tp->t_timers->tt_draincnt++;
 1094         }
 1095 }

Cache object: 665d2bdb25f5ad32453b8105bb6fe9c4


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.