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_timewait.c

Version: -  FREEBSD  -  FREEBSD11  -  FREEBSD10  -  FREEBSD9  -  FREEBSD92  -  FREEBSD91  -  FREEBSD90  -  FREEBSD8  -  FREEBSD82  -  FREEBSD81  -  FREEBSD80  -  FREEBSD7  -  FREEBSD74  -  FREEBSD73  -  FREEBSD72  -  FREEBSD71  -  FREEBSD70  -  FREEBSD6  -  FREEBSD64  -  FREEBSD63  -  FREEBSD62  -  FREEBSD61  -  FREEBSD60  -  FREEBSD5  -  FREEBSD55  -  FREEBSD54  -  FREEBSD53  -  FREEBSD52  -  FREEBSD51  -  FREEBSD50  -  FREEBSD4  -  FREEBSD3  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
    3  *      The Regents of the University of California.  All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 4. Neither the name of the University nor the names of its contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  *
   29  *      @(#)tcp_subr.c  8.2 (Berkeley) 5/24/95
   30  */
   31 
   32 #include <sys/cdefs.h>
   33 __FBSDID("$FreeBSD: stable/7/sys/netinet/tcp_timewait.c 235659 2012-05-19 18:33:28Z bz $");
   34 
   35 #include "opt_inet.h"
   36 #include "opt_inet6.h"
   37 #include "opt_mac.h"
   38 #include "opt_tcpdebug.h"
   39 
   40 #include <sys/param.h>
   41 #include <sys/systm.h>
   42 #include <sys/callout.h>
   43 #include <sys/kernel.h>
   44 #include <sys/sysctl.h>
   45 #include <sys/malloc.h>
   46 #include <sys/mbuf.h>
   47 #include <sys/priv.h>
   48 #include <sys/proc.h>
   49 #include <sys/socket.h>
   50 #include <sys/socketvar.h>
   51 #include <sys/protosw.h>
   52 #include <sys/random.h>
   53 
   54 #include <vm/uma.h>
   55 
   56 #include <net/route.h>
   57 #include <net/if.h>
   58 
   59 #include <netinet/in.h>
   60 #include <netinet/in_systm.h>
   61 #include <netinet/ip.h>
   62 #ifdef INET6
   63 #include <netinet/ip6.h>
   64 #endif
   65 #include <netinet/in_pcb.h>
   66 #ifdef INET6
   67 #include <netinet6/in6_pcb.h>
   68 #endif
   69 #include <netinet/in_var.h>
   70 #include <netinet/ip_var.h>
   71 #ifdef INET6
   72 #include <netinet6/ip6_var.h>
   73 #include <netinet6/scope6_var.h>
   74 #include <netinet6/nd6.h>
   75 #endif
   76 #include <netinet/ip_icmp.h>
   77 #include <netinet/tcp.h>
   78 #include <netinet/tcp_fsm.h>
   79 #include <netinet/tcp_seq.h>
   80 #include <netinet/tcp_timer.h>
   81 #include <netinet/tcp_var.h>
   82 #ifdef INET6
   83 #include <netinet6/tcp6_var.h>
   84 #endif
   85 #include <netinet/tcpip.h>
   86 #ifdef TCPDEBUG
   87 #include <netinet/tcp_debug.h>
   88 #endif
   89 #include <netinet6/ip6protosw.h>
   90 
   91 #include <machine/in_cksum.h>
   92 
   93 #include <security/mac/mac_framework.h>
   94 
   95 static uma_zone_t tcptw_zone;
   96 static int      maxtcptw;
   97 
   98 /*
   99  * The timed wait queue contains references to each of the TCP sessions
  100  * currently in the TIME_WAIT state.  The queue pointers, including the
  101  * queue pointers in each tcptw structure, are protected using the global
  102  * tcbinfo lock, which must be held over queue iteration and modification.
  103  */
  104 static TAILQ_HEAD(, tcptw)      twq_2msl;
  105 
  106 static void     tcp_tw_2msl_reset(struct tcptw *, int);
  107 static void     tcp_tw_2msl_stop(struct tcptw *);
  108 
  109 static int
  110 tcptw_auto_size(void)
  111 {
  112         int halfrange;
  113 
  114         /*
  115          * Max out at half the ephemeral port range so that TIME_WAIT
  116          * sockets don't tie up too many ephemeral ports.
  117          */
  118         if (ipport_lastauto > ipport_firstauto)
  119                 halfrange = (ipport_lastauto - ipport_firstauto) / 2;
  120         else
  121                 halfrange = (ipport_firstauto - ipport_lastauto) / 2;
  122         /* Protect against goofy port ranges smaller than 32. */
  123         return (imin(imax(halfrange, 32), maxsockets / 5));
  124 }
  125 
  126 static int
  127 sysctl_maxtcptw(SYSCTL_HANDLER_ARGS)
  128 {
  129         int error, new;
  130 
  131         if (maxtcptw == 0)
  132                 new = tcptw_auto_size();
  133         else
  134                 new = maxtcptw;
  135         error = sysctl_handle_int(oidp, &new, 0, req);
  136         if (error == 0 && req->newptr)
  137                 if (new >= 32) {
  138                         maxtcptw = new;
  139                         uma_zone_set_max(tcptw_zone, maxtcptw);
  140                 }
  141         return (error);
  142 }
  143 
  144 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, maxtcptw, CTLTYPE_INT|CTLFLAG_RW,
  145     &maxtcptw, 0, sysctl_maxtcptw, "IU",
  146     "Maximum number of compressed TCP TIME_WAIT entries");
  147 
  148 static int      nolocaltimewait = 0;
  149 SYSCTL_INT(_net_inet_tcp, OID_AUTO, nolocaltimewait, CTLFLAG_RW,
  150     &nolocaltimewait, 0,
  151     "Do not create compressed TCP TIME_WAIT entries for local connections");
  152 
  153 void
  154 tcp_tw_zone_change(void)
  155 {
  156 
  157         if (maxtcptw == 0)
  158                 uma_zone_set_max(tcptw_zone, tcptw_auto_size());
  159 }
  160 
  161 void
  162 tcp_tw_init(void)
  163 {
  164 
  165         tcptw_zone = uma_zcreate("tcptw", sizeof(struct tcptw),
  166             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
  167         TUNABLE_INT_FETCH("net.inet.tcp.maxtcptw", &maxtcptw);
  168         if (maxtcptw == 0)
  169                 uma_zone_set_max(tcptw_zone, tcptw_auto_size());
  170         else
  171                 uma_zone_set_max(tcptw_zone, maxtcptw);
  172         TAILQ_INIT(&twq_2msl);
  173 }
  174 
  175 /*
  176  * Move a TCP connection into TIME_WAIT state.
  177  *    tcbinfo is locked.
  178  *    inp is locked, and is unlocked before returning.
  179  */
  180 void
  181 tcp_twstart(struct tcpcb *tp)
  182 {
  183         struct tcptw *tw;
  184         struct inpcb *inp = tp->t_inpcb;
  185         int acknow;
  186         struct socket *so;
  187 
  188         INP_INFO_WLOCK_ASSERT(&tcbinfo);        /* tcp_tw_2msl_reset(). */
  189         INP_WLOCK_ASSERT(inp);
  190 
  191         if (nolocaltimewait && in_localip(inp->inp_faddr)) {
  192                 tp = tcp_close(tp);
  193                 if (tp != NULL)
  194                         INP_WUNLOCK(inp);
  195                 return;
  196         }
  197 
  198         tw = uma_zalloc(tcptw_zone, M_NOWAIT);
  199         if (tw == NULL) {
  200                 tw = tcp_tw_2msl_scan(1);
  201                 if (tw == NULL) {
  202                         tp = tcp_close(tp);
  203                         if (tp != NULL)
  204                                 INP_WUNLOCK(inp);
  205                         return;
  206                 }
  207         }
  208         tw->tw_inpcb = inp;
  209 
  210         /*
  211          * Recover last window size sent.
  212          */
  213         KASSERT(SEQ_GEQ(tp->rcv_adv, tp->rcv_nxt),
  214             ("tcp_twstart negative window: tp %p rcv_nxt %u rcv_adv %u", tp,
  215             tp->rcv_adv, tp->rcv_nxt));
  216         tw->last_win = (tp->rcv_adv - tp->rcv_nxt) >> tp->rcv_scale;
  217 
  218         /*
  219          * Set t_recent if timestamps are used on the connection.
  220          */
  221         if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) ==
  222             (TF_REQ_TSTMP|TF_RCVD_TSTMP)) {
  223                 tw->t_recent = tp->ts_recent;
  224                 tw->ts_offset = tp->ts_offset;
  225         } else {
  226                 tw->t_recent = 0;
  227                 tw->ts_offset = 0;
  228         }
  229 
  230         tw->snd_nxt = tp->snd_nxt;
  231         tw->rcv_nxt = tp->rcv_nxt;
  232         tw->iss     = tp->iss;
  233         tw->irs     = tp->irs;
  234         tw->t_starttime = tp->t_starttime;
  235         tw->tw_time = 0;
  236 
  237 /* XXX
  238  * If this code will
  239  * be used for fin-wait-2 state also, then we may need
  240  * a ts_recent from the last segment.
  241  */
  242         acknow = tp->t_flags & TF_ACKNOW;
  243 
  244         /*
  245          * First, discard tcpcb state, which includes stopping its timers and
  246          * freeing it.  tcp_discardcb() used to also release the inpcb, but
  247          * that work is now done in the caller.
  248          *
  249          * Note: soisdisconnected() call used to be made in tcp_discardcb(),
  250          * and might not be needed here any longer.
  251          */
  252         tcp_discardcb(tp);
  253         so = inp->inp_socket;
  254         soisdisconnected(so);
  255         tw->tw_cred = crhold(so->so_cred);
  256         SOCK_LOCK(so);
  257         tw->tw_so_options = so->so_options;
  258         SOCK_UNLOCK(so);
  259         if (acknow)
  260                 tcp_twrespond(tw, TH_ACK);
  261         inp->inp_ppcb = tw;
  262         inp->inp_flags |= INP_TIMEWAIT;
  263         tcp_tw_2msl_reset(tw, 0);
  264 
  265         /*
  266          * If the inpcb owns the sole reference to the socket, then we can
  267          * detach and free the socket as it is not needed in time wait.
  268          */
  269         if (inp->inp_flags & INP_SOCKREF) {
  270                 KASSERT(so->so_state & SS_PROTOREF,
  271                     ("tcp_twstart: !SS_PROTOREF"));
  272                 inp->inp_flags &= ~INP_SOCKREF;
  273                 INP_WUNLOCK(inp);
  274                 ACCEPT_LOCK();
  275                 SOCK_LOCK(so);
  276                 so->so_state &= ~SS_PROTOREF;
  277                 sofree(so);
  278         } else
  279                 INP_WUNLOCK(inp);
  280 }
  281 
  282 #if 0
  283 /*
  284  * The appromixate rate of ISN increase of Microsoft TCP stacks;
  285  * the actual rate is slightly higher due to the addition of
  286  * random positive increments.
  287  *
  288  * Most other new OSes use semi-randomized ISN values, so we
  289  * do not need to worry about them.
  290  */
  291 #define MS_ISN_BYTES_PER_SECOND         250000
  292 
  293 /*
  294  * Determine if the ISN we will generate has advanced beyond the last
  295  * sequence number used by the previous connection.  If so, indicate
  296  * that it is safe to recycle this tw socket by returning 1.
  297  */
  298 int
  299 tcp_twrecycleable(struct tcptw *tw)
  300 {
  301         tcp_seq new_iss = tw->iss;
  302         tcp_seq new_irs = tw->irs;
  303 
  304         INP_INFO_WLOCK_ASSERT(&tcbinfo);
  305         new_iss += (ticks - tw->t_starttime) * (ISN_BYTES_PER_SECOND / hz);
  306         new_irs += (ticks - tw->t_starttime) * (MS_ISN_BYTES_PER_SECOND / hz);
  307 
  308         if (SEQ_GT(new_iss, tw->snd_nxt) && SEQ_GT(new_irs, tw->rcv_nxt))
  309                 return (1);
  310         else
  311                 return (0);
  312 }
  313 #endif
  314 
  315 /*
  316  * Returns 1 if the TIME_WAIT state was killed and we should start over,
  317  * looking for a pcb in the listen state.  Returns 0 otherwise.
  318  */
  319 int
  320 tcp_twcheck(struct inpcb *inp, struct tcpopt *to, struct tcphdr *th,
  321     struct mbuf *m, int tlen)
  322 {
  323         struct tcptw *tw;
  324         int thflags;
  325         tcp_seq seq;
  326 
  327         /* tcbinfo lock required for tcp_twclose(), tcp_tw_2msl_reset(). */
  328         INP_INFO_WLOCK_ASSERT(&tcbinfo);
  329         INP_WLOCK_ASSERT(inp);
  330 
  331         /*
  332          * XXXRW: Time wait state for inpcb has been recycled, but inpcb is
  333          * still present.  This is undesirable, but temporarily necessary
  334          * until we work out how to handle inpcb's who's timewait state has
  335          * been removed.
  336          */
  337         tw = intotw(inp);
  338         if (tw == NULL)
  339                 goto drop;
  340 
  341         thflags = th->th_flags;
  342 
  343         /*
  344          * NOTE: for FIN_WAIT_2 (to be added later),
  345          * must validate sequence number before accepting RST
  346          */
  347 
  348         /*
  349          * If the segment contains RST:
  350          *      Drop the segment - see Stevens, vol. 2, p. 964 and
  351          *      RFC 1337.
  352          */
  353         if (thflags & TH_RST)
  354                 goto drop;
  355 
  356 #if 0
  357 /* PAWS not needed at the moment */
  358         /*
  359          * RFC 1323 PAWS: If we have a timestamp reply on this segment
  360          * and it's less than ts_recent, drop it.
  361          */
  362         if ((to.to_flags & TOF_TS) != 0 && tp->ts_recent &&
  363             TSTMP_LT(to.to_tsval, tp->ts_recent)) {
  364                 if ((thflags & TH_ACK) == 0)
  365                         goto drop;
  366                 goto ack;
  367         }
  368         /*
  369          * ts_recent is never updated because we never accept new segments.
  370          */
  371 #endif
  372 
  373         /*
  374          * If a new connection request is received
  375          * while in TIME_WAIT, drop the old connection
  376          * and start over if the sequence numbers
  377          * are above the previous ones.
  378          */
  379         if ((thflags & TH_SYN) && SEQ_GT(th->th_seq, tw->rcv_nxt)) {
  380                 tcp_twclose(tw, 0);
  381                 return (1);
  382         }
  383 
  384         /*
  385          * Drop the segment if it does not contain an ACK.
  386          */
  387         if ((thflags & TH_ACK) == 0)
  388                 goto drop;
  389 
  390         /*
  391          * Reset the 2MSL timer if this is a duplicate FIN.
  392          */
  393         if (thflags & TH_FIN) {
  394                 seq = th->th_seq + tlen + (thflags & TH_SYN ? 1 : 0);
  395                 if (seq + 1 == tw->rcv_nxt)
  396                         tcp_tw_2msl_reset(tw, 1);
  397         }
  398 
  399         /*
  400          * Acknowledge the segment if it has data or is not a duplicate ACK.
  401          */
  402         if (thflags != TH_ACK || tlen != 0 ||
  403             th->th_seq != tw->rcv_nxt || th->th_ack != tw->snd_nxt)
  404                 tcp_twrespond(tw, TH_ACK);
  405 drop:
  406         INP_WUNLOCK(inp);
  407         m_freem(m);
  408         return (0);
  409 }
  410 
  411 void
  412 tcp_twclose(struct tcptw *tw, int reuse)
  413 {
  414         struct socket *so;
  415         struct inpcb *inp;
  416 
  417         /*
  418          * At this point, we are in one of two situations:
  419          *
  420          * (1) We have no socket, just an inpcb<->twtcp pair.  We can free
  421          *     all state.
  422          *
  423          * (2) We have a socket -- if we own a reference, release it and
  424          *     notify the socket layer.
  425          */
  426         inp = tw->tw_inpcb;
  427         KASSERT((inp->inp_flags & INP_TIMEWAIT), ("tcp_twclose: !timewait"));
  428         KASSERT(intotw(inp) == tw, ("tcp_twclose: inp_ppcb != tw"));
  429         INP_INFO_WLOCK_ASSERT(&tcbinfo);        /* tcp_tw_2msl_stop(). */
  430         INP_WLOCK_ASSERT(inp);
  431 
  432         tw->tw_inpcb = NULL;
  433         tcp_tw_2msl_stop(tw);
  434         inp->inp_ppcb = NULL;
  435         in_pcbdrop(inp);
  436 
  437         so = inp->inp_socket;
  438         if (so != NULL) {
  439                 /*
  440                  * If there's a socket, handle two cases: first, we own a
  441                  * strong reference, which we will now release, or we don't
  442                  * in which case another reference exists (XXXRW: think
  443                  * about this more), and we don't need to take action.
  444                  */
  445                 if (inp->inp_flags & INP_SOCKREF) {
  446                         inp->inp_flags &= ~INP_SOCKREF;
  447                         INP_WUNLOCK(inp);
  448                         ACCEPT_LOCK();
  449                         SOCK_LOCK(so);
  450                         KASSERT(so->so_state & SS_PROTOREF,
  451                             ("tcp_twclose: INP_SOCKREF && !SS_PROTOREF"));
  452                         so->so_state &= ~SS_PROTOREF;
  453                         sofree(so);
  454                 } else {
  455                         /*
  456                          * If we don't own the only reference, the socket and
  457                          * inpcb need to be left around to be handled by
  458                          * tcp_usr_detach() later.
  459                          */
  460                         INP_WUNLOCK(inp);
  461                 }
  462         } else
  463                 in_pcbfree(inp);
  464         tcpstat.tcps_closed++;
  465         crfree(tw->tw_cred);
  466         tw->tw_cred = NULL;
  467         if (reuse)
  468                 return;
  469         uma_zfree(tcptw_zone, tw);
  470 }
  471 
  472 int
  473 tcp_twrespond(struct tcptw *tw, int flags)
  474 {
  475         struct inpcb *inp = tw->tw_inpcb;
  476         struct tcphdr *th;
  477         struct mbuf *m;
  478         struct ip *ip = NULL;
  479         u_int hdrlen, optlen;
  480         int error;
  481         struct tcpopt to;
  482 #ifdef INET6
  483         struct ip6_hdr *ip6 = NULL;
  484         int isipv6 = inp->inp_inc.inc_flags & INC_ISIPV6;
  485 #endif
  486 
  487         INP_WLOCK_ASSERT(inp);
  488 
  489         m = m_gethdr(M_DONTWAIT, MT_DATA);
  490         if (m == NULL)
  491                 return (ENOBUFS);
  492         m->m_data += max_linkhdr;
  493 
  494 #ifdef MAC
  495         mac_create_mbuf_from_inpcb(inp, m);
  496 #endif
  497 
  498 #ifdef INET6
  499         if (isipv6) {
  500                 hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
  501                 ip6 = mtod(m, struct ip6_hdr *);
  502                 th = (struct tcphdr *)(ip6 + 1);
  503                 tcpip_fillheaders(inp, ip6, th);
  504         } else
  505 #endif
  506         {
  507                 hdrlen = sizeof(struct tcpiphdr);
  508                 ip = mtod(m, struct ip *);
  509                 th = (struct tcphdr *)(ip + 1);
  510                 tcpip_fillheaders(inp, ip, th);
  511         }
  512         to.to_flags = 0;
  513 
  514         /*
  515          * Send a timestamp and echo-reply if both our side and our peer
  516          * have sent timestamps in our SYN's and this is not a RST.
  517          */
  518         if (tw->t_recent && flags == TH_ACK) {
  519                 to.to_flags |= TOF_TS;
  520                 to.to_tsval = tcp_ts_getticks() + tw->ts_offset;
  521                 to.to_tsecr = tw->t_recent;
  522         }
  523         optlen = tcp_addoptions(&to, (u_char *)(th + 1));
  524 
  525         m->m_len = hdrlen + optlen;
  526         m->m_pkthdr.len = m->m_len;
  527 
  528         KASSERT(max_linkhdr + m->m_len <= MHLEN, ("tcptw: mbuf too small"));
  529 
  530         th->th_seq = htonl(tw->snd_nxt);
  531         th->th_ack = htonl(tw->rcv_nxt);
  532         th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
  533         th->th_flags = flags;
  534         th->th_win = htons(tw->last_win);
  535 
  536 #ifdef INET6
  537         if (isipv6) {
  538                 th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(struct ip6_hdr),
  539                     sizeof(struct tcphdr) + optlen);
  540                 ip6->ip6_hlim = in6_selecthlim(inp, NULL);
  541                 error = ip6_output(m, inp->in6p_outputopts, NULL,
  542                     (tw->tw_so_options & SO_DONTROUTE), NULL, NULL, inp);
  543         } else
  544 #endif
  545         {
  546                 th->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
  547                     htons(sizeof(struct tcphdr) + optlen + IPPROTO_TCP));
  548                 m->m_pkthdr.csum_flags = CSUM_TCP;
  549                 m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
  550                 ip->ip_len = m->m_pkthdr.len;
  551                 if (path_mtu_discovery)
  552                         ip->ip_off |= IP_DF;
  553                 error = ip_output(m, inp->inp_options, NULL,
  554                     ((tw->tw_so_options & SO_DONTROUTE) ? IP_ROUTETOIF : 0),
  555                     NULL, inp);
  556         }
  557         if (flags & TH_ACK)
  558                 tcpstat.tcps_sndacks++;
  559         else
  560                 tcpstat.tcps_sndctrl++;
  561         tcpstat.tcps_sndtotal++;
  562         return (error);
  563 }
  564 
  565 static void
  566 tcp_tw_2msl_reset(struct tcptw *tw, int rearm)
  567 {
  568 
  569         INP_INFO_WLOCK_ASSERT(&tcbinfo);
  570         INP_WLOCK_ASSERT(tw->tw_inpcb);
  571         if (rearm)
  572                 TAILQ_REMOVE(&twq_2msl, tw, tw_2msl);
  573         tw->tw_time = ticks + 2 * tcp_msl;
  574         TAILQ_INSERT_TAIL(&twq_2msl, tw, tw_2msl);
  575 }
  576 
  577 static void
  578 tcp_tw_2msl_stop(struct tcptw *tw)
  579 {
  580 
  581         INP_INFO_WLOCK_ASSERT(&tcbinfo);
  582         TAILQ_REMOVE(&twq_2msl, tw, tw_2msl);
  583 }
  584 
  585 struct tcptw *
  586 tcp_tw_2msl_scan(int reuse)
  587 {
  588         struct tcptw *tw;
  589 
  590         INP_INFO_WLOCK_ASSERT(&tcbinfo);
  591         for (;;) {
  592                 tw = TAILQ_FIRST(&twq_2msl);
  593                 if (tw == NULL || (!reuse && (tw->tw_time - ticks) > 0))
  594                         break;
  595                 INP_WLOCK(tw->tw_inpcb);
  596                 tcp_twclose(tw, reuse);
  597                 if (reuse)
  598                         return (tw);
  599         }
  600         return (NULL);
  601 }

Cache object: 21c266e7bbf1fb7bd677db0ce9b3ece6


[ 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.