The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/netinet/tcp_usrreq.c

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    1 /*-
    2  * Copyright (c) 1982, 1986, 1988, 1993
    3  *      The Regents of the University of California.
    4  * Copyright (c) 2006-2007 Robert N. M. Watson
    5  * Copyright (c) 2010-2011 Juniper Networks, Inc.
    6  * All rights reserved.
    7  *
    8  * Portions of this software were developed by Robert N. M. Watson under
    9  * contract to Juniper Networks, Inc.
   10  *
   11  * Redistribution and use in source and binary forms, with or without
   12  * modification, are permitted provided that the following conditions
   13  * are met:
   14  * 1. Redistributions of source code must retain the above copyright
   15  *    notice, this list of conditions and the following disclaimer.
   16  * 2. Redistributions in binary form must reproduce the above copyright
   17  *    notice, this list of conditions and the following disclaimer in the
   18  *    documentation and/or other materials provided with the distribution.
   19  * 4. Neither the name of the University nor the names of its contributors
   20  *    may be used to endorse or promote products derived from this software
   21  *    without specific prior written permission.
   22  *
   23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   33  * SUCH DAMAGE.
   34  *
   35  *      From: @(#)tcp_usrreq.c  8.2 (Berkeley) 1/3/94
   36  */
   37 
   38 #include <sys/cdefs.h>
   39 __FBSDID("$FreeBSD: releng/10.2/sys/netinet/tcp_usrreq.c 282968 2015-05-15 12:35:18Z jch $");
   40 
   41 #include "opt_ddb.h"
   42 #include "opt_inet.h"
   43 #include "opt_inet6.h"
   44 #include "opt_tcpdebug.h"
   45 
   46 #include <sys/param.h>
   47 #include <sys/systm.h>
   48 #include <sys/limits.h>
   49 #include <sys/malloc.h>
   50 #include <sys/kernel.h>
   51 #include <sys/sysctl.h>
   52 #include <sys/mbuf.h>
   53 #ifdef INET6
   54 #include <sys/domain.h>
   55 #endif /* INET6 */
   56 #include <sys/socket.h>
   57 #include <sys/socketvar.h>
   58 #include <sys/protosw.h>
   59 #include <sys/proc.h>
   60 #include <sys/jail.h>
   61 
   62 #ifdef DDB
   63 #include <ddb/ddb.h>
   64 #endif
   65 
   66 #include <net/if.h>
   67 #include <net/route.h>
   68 #include <net/vnet.h>
   69 
   70 #include <netinet/cc.h>
   71 #include <netinet/in.h>
   72 #include <netinet/in_pcb.h>
   73 #include <netinet/in_systm.h>
   74 #include <netinet/in_var.h>
   75 #include <netinet/ip_var.h>
   76 #ifdef INET6
   77 #include <netinet/ip6.h>
   78 #include <netinet6/in6_pcb.h>
   79 #include <netinet6/ip6_var.h>
   80 #include <netinet6/scope6_var.h>
   81 #endif
   82 #include <netinet/tcp_fsm.h>
   83 #include <netinet/tcp_seq.h>
   84 #include <netinet/tcp_timer.h>
   85 #include <netinet/tcp_var.h>
   86 #include <netinet/tcpip.h>
   87 #ifdef TCPDEBUG
   88 #include <netinet/tcp_debug.h>
   89 #endif
   90 #ifdef TCP_OFFLOAD
   91 #include <netinet/tcp_offload.h>
   92 #endif
   93 
   94 /*
   95  * TCP protocol interface to socket abstraction.
   96  */
   97 static int      tcp_attach(struct socket *);
   98 #ifdef INET
   99 static int      tcp_connect(struct tcpcb *, struct sockaddr *,
  100                     struct thread *td);
  101 #endif /* INET */
  102 #ifdef INET6
  103 static int      tcp6_connect(struct tcpcb *, struct sockaddr *,
  104                     struct thread *td);
  105 #endif /* INET6 */
  106 static void     tcp_disconnect(struct tcpcb *);
  107 static void     tcp_usrclosed(struct tcpcb *);
  108 static void     tcp_fill_info(struct tcpcb *, struct tcp_info *);
  109 
  110 #ifdef TCPDEBUG
  111 #define TCPDEBUG0       int ostate = 0
  112 #define TCPDEBUG1()     ostate = tp ? tp->t_state : 0
  113 #define TCPDEBUG2(req)  if (tp && (so->so_options & SO_DEBUG)) \
  114                                 tcp_trace(TA_USER, ostate, tp, 0, 0, req)
  115 #else
  116 #define TCPDEBUG0
  117 #define TCPDEBUG1()
  118 #define TCPDEBUG2(req)
  119 #endif
  120 
  121 /*
  122  * TCP attaches to socket via pru_attach(), reserving space,
  123  * and an internet control block.
  124  */
  125 static int
  126 tcp_usr_attach(struct socket *so, int proto, struct thread *td)
  127 {
  128         struct inpcb *inp;
  129         struct tcpcb *tp = NULL;
  130         int error;
  131         TCPDEBUG0;
  132 
  133         inp = sotoinpcb(so);
  134         KASSERT(inp == NULL, ("tcp_usr_attach: inp != NULL"));
  135         TCPDEBUG1();
  136 
  137         error = tcp_attach(so);
  138         if (error)
  139                 goto out;
  140 
  141         if ((so->so_options & SO_LINGER) && so->so_linger == 0)
  142                 so->so_linger = TCP_LINGERTIME;
  143 
  144         inp = sotoinpcb(so);
  145         tp = intotcpcb(inp);
  146 out:
  147         TCPDEBUG2(PRU_ATTACH);
  148         return error;
  149 }
  150 
  151 /*
  152  * tcp_detach is called when the socket layer loses its final reference
  153  * to the socket, be it a file descriptor reference, a reference from TCP,
  154  * etc.  At this point, there is only one case in which we will keep around
  155  * inpcb state: time wait.
  156  *
  157  * This function can probably be re-absorbed back into tcp_usr_detach() now
  158  * that there is a single detach path.
  159  */
  160 static void
  161 tcp_detach(struct socket *so, struct inpcb *inp)
  162 {
  163         struct tcpcb *tp;
  164 
  165         INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
  166         INP_WLOCK_ASSERT(inp);
  167 
  168         KASSERT(so->so_pcb == inp, ("tcp_detach: so_pcb != inp"));
  169         KASSERT(inp->inp_socket == so, ("tcp_detach: inp_socket != so"));
  170 
  171         tp = intotcpcb(inp);
  172 
  173         if (inp->inp_flags & INP_TIMEWAIT) {
  174                 /*
  175                  * There are two cases to handle: one in which the time wait
  176                  * state is being discarded (INP_DROPPED), and one in which
  177                  * this connection will remain in timewait.  In the former,
  178                  * it is time to discard all state (except tcptw, which has
  179                  * already been discarded by the timewait close code, which
  180                  * should be further up the call stack somewhere).  In the
  181                  * latter case, we detach from the socket, but leave the pcb
  182                  * present until timewait ends.
  183                  *
  184                  * XXXRW: Would it be cleaner to free the tcptw here?
  185                  *
  186                  * Astute question indeed, from twtcp perspective there are
  187                  * three cases to consider:
  188                  *
  189                  * #1 tcp_detach is called at tcptw creation time by
  190                  *  tcp_twstart, then do not discard the newly created tcptw
  191                  *  and leave inpcb present until timewait ends
  192                  * #2 tcp_detach is called at timewait end (or reuse) by
  193                  *  tcp_twclose, then the tcptw has already been discarded
  194                  *  and inpcb is freed here
  195                  * #3 tcp_detach is called() after timewait ends (or reuse)
  196                  *  (e.g. by soclose), then tcptw has already been discarded
  197                  *  and inpcb is freed here
  198                  *
  199                  *  In all three cases the tcptw should not be freed here.
  200                  */
  201                 if (inp->inp_flags & INP_DROPPED) {
  202                         KASSERT(tp == NULL, ("tcp_detach: INP_TIMEWAIT && "
  203                             "INP_DROPPED && tp != NULL"));
  204                         in_pcbdetach(inp);
  205                         in_pcbfree(inp);
  206                 } else {
  207                         in_pcbdetach(inp);
  208                         INP_WUNLOCK(inp);
  209                 }
  210         } else {
  211                 /*
  212                  * If the connection is not in timewait, we consider two
  213                  * two conditions: one in which no further processing is
  214                  * necessary (dropped || embryonic), and one in which TCP is
  215                  * not yet done, but no longer requires the socket, so the
  216                  * pcb will persist for the time being.
  217                  *
  218                  * XXXRW: Does the second case still occur?
  219                  */
  220                 if (inp->inp_flags & INP_DROPPED ||
  221                     tp->t_state < TCPS_SYN_SENT) {
  222                         tcp_discardcb(tp);
  223                         in_pcbdetach(inp);
  224                         in_pcbfree(inp);
  225                 } else {
  226                         in_pcbdetach(inp);
  227                         INP_WUNLOCK(inp);
  228                 }
  229         }
  230 }
  231 
  232 /*
  233  * pru_detach() detaches the TCP protocol from the socket.
  234  * If the protocol state is non-embryonic, then can't
  235  * do this directly: have to initiate a pru_disconnect(),
  236  * which may finish later; embryonic TCB's can just
  237  * be discarded here.
  238  */
  239 static void
  240 tcp_usr_detach(struct socket *so)
  241 {
  242         struct inpcb *inp;
  243 
  244         inp = sotoinpcb(so);
  245         KASSERT(inp != NULL, ("tcp_usr_detach: inp == NULL"));
  246         INP_INFO_WLOCK(&V_tcbinfo);
  247         INP_WLOCK(inp);
  248         KASSERT(inp->inp_socket != NULL,
  249             ("tcp_usr_detach: inp_socket == NULL"));
  250         tcp_detach(so, inp);
  251         INP_INFO_WUNLOCK(&V_tcbinfo);
  252 }
  253 
  254 #ifdef INET
  255 /*
  256  * Give the socket an address.
  257  */
  258 static int
  259 tcp_usr_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
  260 {
  261         int error = 0;
  262         struct inpcb *inp;
  263         struct tcpcb *tp = NULL;
  264         struct sockaddr_in *sinp;
  265 
  266         sinp = (struct sockaddr_in *)nam;
  267         if (nam->sa_len != sizeof (*sinp))
  268                 return (EINVAL);
  269         /*
  270          * Must check for multicast addresses and disallow binding
  271          * to them.
  272          */
  273         if (sinp->sin_family == AF_INET &&
  274             IN_MULTICAST(ntohl(sinp->sin_addr.s_addr)))
  275                 return (EAFNOSUPPORT);
  276 
  277         TCPDEBUG0;
  278         inp = sotoinpcb(so);
  279         KASSERT(inp != NULL, ("tcp_usr_bind: inp == NULL"));
  280         INP_WLOCK(inp);
  281         if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
  282                 error = EINVAL;
  283                 goto out;
  284         }
  285         tp = intotcpcb(inp);
  286         TCPDEBUG1();
  287         INP_HASH_WLOCK(&V_tcbinfo);
  288         error = in_pcbbind(inp, nam, td->td_ucred);
  289         INP_HASH_WUNLOCK(&V_tcbinfo);
  290 out:
  291         TCPDEBUG2(PRU_BIND);
  292         INP_WUNLOCK(inp);
  293 
  294         return (error);
  295 }
  296 #endif /* INET */
  297 
  298 #ifdef INET6
  299 static int
  300 tcp6_usr_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
  301 {
  302         int error = 0;
  303         struct inpcb *inp;
  304         struct tcpcb *tp = NULL;
  305         struct sockaddr_in6 *sin6p;
  306 
  307         sin6p = (struct sockaddr_in6 *)nam;
  308         if (nam->sa_len != sizeof (*sin6p))
  309                 return (EINVAL);
  310         /*
  311          * Must check for multicast addresses and disallow binding
  312          * to them.
  313          */
  314         if (sin6p->sin6_family == AF_INET6 &&
  315             IN6_IS_ADDR_MULTICAST(&sin6p->sin6_addr))
  316                 return (EAFNOSUPPORT);
  317 
  318         TCPDEBUG0;
  319         inp = sotoinpcb(so);
  320         KASSERT(inp != NULL, ("tcp6_usr_bind: inp == NULL"));
  321         INP_WLOCK(inp);
  322         if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
  323                 error = EINVAL;
  324                 goto out;
  325         }
  326         tp = intotcpcb(inp);
  327         TCPDEBUG1();
  328         INP_HASH_WLOCK(&V_tcbinfo);
  329         inp->inp_vflag &= ~INP_IPV4;
  330         inp->inp_vflag |= INP_IPV6;
  331 #ifdef INET
  332         if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
  333                 if (IN6_IS_ADDR_UNSPECIFIED(&sin6p->sin6_addr))
  334                         inp->inp_vflag |= INP_IPV4;
  335                 else if (IN6_IS_ADDR_V4MAPPED(&sin6p->sin6_addr)) {
  336                         struct sockaddr_in sin;
  337 
  338                         in6_sin6_2_sin(&sin, sin6p);
  339                         inp->inp_vflag |= INP_IPV4;
  340                         inp->inp_vflag &= ~INP_IPV6;
  341                         error = in_pcbbind(inp, (struct sockaddr *)&sin,
  342                             td->td_ucred);
  343                         INP_HASH_WUNLOCK(&V_tcbinfo);
  344                         goto out;
  345                 }
  346         }
  347 #endif
  348         error = in6_pcbbind(inp, nam, td->td_ucred);
  349         INP_HASH_WUNLOCK(&V_tcbinfo);
  350 out:
  351         TCPDEBUG2(PRU_BIND);
  352         INP_WUNLOCK(inp);
  353         return (error);
  354 }
  355 #endif /* INET6 */
  356 
  357 #ifdef INET
  358 /*
  359  * Prepare to accept connections.
  360  */
  361 static int
  362 tcp_usr_listen(struct socket *so, int backlog, struct thread *td)
  363 {
  364         int error = 0;
  365         struct inpcb *inp;
  366         struct tcpcb *tp = NULL;
  367 
  368         TCPDEBUG0;
  369         inp = sotoinpcb(so);
  370         KASSERT(inp != NULL, ("tcp_usr_listen: inp == NULL"));
  371         INP_WLOCK(inp);
  372         if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
  373                 error = EINVAL;
  374                 goto out;
  375         }
  376         tp = intotcpcb(inp);
  377         TCPDEBUG1();
  378         SOCK_LOCK(so);
  379         error = solisten_proto_check(so);
  380         INP_HASH_WLOCK(&V_tcbinfo);
  381         if (error == 0 && inp->inp_lport == 0)
  382                 error = in_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
  383         INP_HASH_WUNLOCK(&V_tcbinfo);
  384         if (error == 0) {
  385                 tcp_state_change(tp, TCPS_LISTEN);
  386                 solisten_proto(so, backlog);
  387 #ifdef TCP_OFFLOAD
  388                 if ((so->so_options & SO_NO_OFFLOAD) == 0)
  389                         tcp_offload_listen_start(tp);
  390 #endif
  391         }
  392         SOCK_UNLOCK(so);
  393 
  394 out:
  395         TCPDEBUG2(PRU_LISTEN);
  396         INP_WUNLOCK(inp);
  397         return (error);
  398 }
  399 #endif /* INET */
  400 
  401 #ifdef INET6
  402 static int
  403 tcp6_usr_listen(struct socket *so, int backlog, struct thread *td)
  404 {
  405         int error = 0;
  406         struct inpcb *inp;
  407         struct tcpcb *tp = NULL;
  408 
  409         TCPDEBUG0;
  410         inp = sotoinpcb(so);
  411         KASSERT(inp != NULL, ("tcp6_usr_listen: inp == NULL"));
  412         INP_WLOCK(inp);
  413         if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
  414                 error = EINVAL;
  415                 goto out;
  416         }
  417         tp = intotcpcb(inp);
  418         TCPDEBUG1();
  419         SOCK_LOCK(so);
  420         error = solisten_proto_check(so);
  421         INP_HASH_WLOCK(&V_tcbinfo);
  422         if (error == 0 && inp->inp_lport == 0) {
  423                 inp->inp_vflag &= ~INP_IPV4;
  424                 if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0)
  425                         inp->inp_vflag |= INP_IPV4;
  426                 error = in6_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
  427         }
  428         INP_HASH_WUNLOCK(&V_tcbinfo);
  429         if (error == 0) {
  430                 tcp_state_change(tp, TCPS_LISTEN);
  431                 solisten_proto(so, backlog);
  432 #ifdef TCP_OFFLOAD
  433                 if ((so->so_options & SO_NO_OFFLOAD) == 0)
  434                         tcp_offload_listen_start(tp);
  435 #endif
  436         }
  437         SOCK_UNLOCK(so);
  438 
  439 out:
  440         TCPDEBUG2(PRU_LISTEN);
  441         INP_WUNLOCK(inp);
  442         return (error);
  443 }
  444 #endif /* INET6 */
  445 
  446 #ifdef INET
  447 /*
  448  * Initiate connection to peer.
  449  * Create a template for use in transmissions on this connection.
  450  * Enter SYN_SENT state, and mark socket as connecting.
  451  * Start keep-alive timer, and seed output sequence space.
  452  * Send initial segment on connection.
  453  */
  454 static int
  455 tcp_usr_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
  456 {
  457         int error = 0;
  458         struct inpcb *inp;
  459         struct tcpcb *tp = NULL;
  460         struct sockaddr_in *sinp;
  461 
  462         sinp = (struct sockaddr_in *)nam;
  463         if (nam->sa_len != sizeof (*sinp))
  464                 return (EINVAL);
  465         /*
  466          * Must disallow TCP ``connections'' to multicast addresses.
  467          */
  468         if (sinp->sin_family == AF_INET
  469             && IN_MULTICAST(ntohl(sinp->sin_addr.s_addr)))
  470                 return (EAFNOSUPPORT);
  471         if ((error = prison_remote_ip4(td->td_ucred, &sinp->sin_addr)) != 0)
  472                 return (error);
  473 
  474         TCPDEBUG0;
  475         inp = sotoinpcb(so);
  476         KASSERT(inp != NULL, ("tcp_usr_connect: inp == NULL"));
  477         INP_WLOCK(inp);
  478         if (inp->inp_flags & INP_TIMEWAIT) {
  479                 error = EADDRINUSE;
  480                 goto out;
  481         }
  482         if (inp->inp_flags & INP_DROPPED) {
  483                 error = ECONNREFUSED;
  484                 goto out;
  485         }
  486         tp = intotcpcb(inp);
  487         TCPDEBUG1();
  488         if ((error = tcp_connect(tp, nam, td)) != 0)
  489                 goto out;
  490 #ifdef TCP_OFFLOAD
  491         if (registered_toedevs > 0 &&
  492             (so->so_options & SO_NO_OFFLOAD) == 0 &&
  493             (error = tcp_offload_connect(so, nam)) == 0)
  494                 goto out;
  495 #endif
  496         tcp_timer_activate(tp, TT_KEEP, TP_KEEPINIT(tp));
  497         error = tcp_output(tp);
  498 out:
  499         TCPDEBUG2(PRU_CONNECT);
  500         INP_WUNLOCK(inp);
  501         return (error);
  502 }
  503 #endif /* INET */
  504 
  505 #ifdef INET6
  506 static int
  507 tcp6_usr_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
  508 {
  509         int error = 0;
  510         struct inpcb *inp;
  511         struct tcpcb *tp = NULL;
  512         struct sockaddr_in6 *sin6p;
  513 
  514         TCPDEBUG0;
  515 
  516         sin6p = (struct sockaddr_in6 *)nam;
  517         if (nam->sa_len != sizeof (*sin6p))
  518                 return (EINVAL);
  519         /*
  520          * Must disallow TCP ``connections'' to multicast addresses.
  521          */
  522         if (sin6p->sin6_family == AF_INET6
  523             && IN6_IS_ADDR_MULTICAST(&sin6p->sin6_addr))
  524                 return (EAFNOSUPPORT);
  525 
  526         inp = sotoinpcb(so);
  527         KASSERT(inp != NULL, ("tcp6_usr_connect: inp == NULL"));
  528         INP_WLOCK(inp);
  529         if (inp->inp_flags & INP_TIMEWAIT) {
  530                 error = EADDRINUSE;
  531                 goto out;
  532         }
  533         if (inp->inp_flags & INP_DROPPED) {
  534                 error = ECONNREFUSED;
  535                 goto out;
  536         }
  537         tp = intotcpcb(inp);
  538         TCPDEBUG1();
  539 #ifdef INET
  540         /*
  541          * XXXRW: Some confusion: V4/V6 flags relate to binding, and
  542          * therefore probably require the hash lock, which isn't held here.
  543          * Is this a significant problem?
  544          */
  545         if (IN6_IS_ADDR_V4MAPPED(&sin6p->sin6_addr)) {
  546                 struct sockaddr_in sin;
  547 
  548                 if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0) {
  549                         error = EINVAL;
  550                         goto out;
  551                 }
  552 
  553                 in6_sin6_2_sin(&sin, sin6p);
  554                 inp->inp_vflag |= INP_IPV4;
  555                 inp->inp_vflag &= ~INP_IPV6;
  556                 if ((error = prison_remote_ip4(td->td_ucred,
  557                     &sin.sin_addr)) != 0)
  558                         goto out;
  559                 if ((error = tcp_connect(tp, (struct sockaddr *)&sin, td)) != 0)
  560                         goto out;
  561 #ifdef TCP_OFFLOAD
  562                 if (registered_toedevs > 0 &&
  563                     (so->so_options & SO_NO_OFFLOAD) == 0 &&
  564                     (error = tcp_offload_connect(so, nam)) == 0)
  565                         goto out;
  566 #endif
  567                 error = tcp_output(tp);
  568                 goto out;
  569         }
  570 #endif
  571         inp->inp_vflag &= ~INP_IPV4;
  572         inp->inp_vflag |= INP_IPV6;
  573         inp->inp_inc.inc_flags |= INC_ISIPV6;
  574         if ((error = prison_remote_ip6(td->td_ucred, &sin6p->sin6_addr)) != 0)
  575                 goto out;
  576         if ((error = tcp6_connect(tp, nam, td)) != 0)
  577                 goto out;
  578 #ifdef TCP_OFFLOAD
  579         if (registered_toedevs > 0 &&
  580             (so->so_options & SO_NO_OFFLOAD) == 0 &&
  581             (error = tcp_offload_connect(so, nam)) == 0)
  582                 goto out;
  583 #endif
  584         tcp_timer_activate(tp, TT_KEEP, TP_KEEPINIT(tp));
  585         error = tcp_output(tp);
  586 
  587 out:
  588         TCPDEBUG2(PRU_CONNECT);
  589         INP_WUNLOCK(inp);
  590         return (error);
  591 }
  592 #endif /* INET6 */
  593 
  594 /*
  595  * Initiate disconnect from peer.
  596  * If connection never passed embryonic stage, just drop;
  597  * else if don't need to let data drain, then can just drop anyways,
  598  * else have to begin TCP shutdown process: mark socket disconnecting,
  599  * drain unread data, state switch to reflect user close, and
  600  * send segment (e.g. FIN) to peer.  Socket will be really disconnected
  601  * when peer sends FIN and acks ours.
  602  *
  603  * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
  604  */
  605 static int
  606 tcp_usr_disconnect(struct socket *so)
  607 {
  608         struct inpcb *inp;
  609         struct tcpcb *tp = NULL;
  610         int error = 0;
  611 
  612         TCPDEBUG0;
  613         INP_INFO_WLOCK(&V_tcbinfo);
  614         inp = sotoinpcb(so);
  615         KASSERT(inp != NULL, ("tcp_usr_disconnect: inp == NULL"));
  616         INP_WLOCK(inp);
  617         if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
  618                 error = ECONNRESET;
  619                 goto out;
  620         }
  621         tp = intotcpcb(inp);
  622         TCPDEBUG1();
  623         tcp_disconnect(tp);
  624 out:
  625         TCPDEBUG2(PRU_DISCONNECT);
  626         INP_WUNLOCK(inp);
  627         INP_INFO_WUNLOCK(&V_tcbinfo);
  628         return (error);
  629 }
  630 
  631 #ifdef INET
  632 /*
  633  * Accept a connection.  Essentially all the work is done at higher levels;
  634  * just return the address of the peer, storing through addr.
  635  *
  636  * The rationale for acquiring the tcbinfo lock here is somewhat complicated,
  637  * and is described in detail in the commit log entry for r175612.  Acquiring
  638  * it delays an accept(2) racing with sonewconn(), which inserts the socket
  639  * before the inpcb address/port fields are initialized.  A better fix would
  640  * prevent the socket from being placed in the listen queue until all fields
  641  * are fully initialized.
  642  */
  643 static int
  644 tcp_usr_accept(struct socket *so, struct sockaddr **nam)
  645 {
  646         int error = 0;
  647         struct inpcb *inp = NULL;
  648         struct tcpcb *tp = NULL;
  649         struct in_addr addr;
  650         in_port_t port = 0;
  651         TCPDEBUG0;
  652 
  653         if (so->so_state & SS_ISDISCONNECTED)
  654                 return (ECONNABORTED);
  655 
  656         inp = sotoinpcb(so);
  657         KASSERT(inp != NULL, ("tcp_usr_accept: inp == NULL"));
  658         INP_INFO_RLOCK(&V_tcbinfo);
  659         INP_WLOCK(inp);
  660         if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
  661                 error = ECONNABORTED;
  662                 goto out;
  663         }
  664         tp = intotcpcb(inp);
  665         TCPDEBUG1();
  666 
  667         /*
  668          * We inline in_getpeeraddr and COMMON_END here, so that we can
  669          * copy the data of interest and defer the malloc until after we
  670          * release the lock.
  671          */
  672         port = inp->inp_fport;
  673         addr = inp->inp_faddr;
  674 
  675 out:
  676         TCPDEBUG2(PRU_ACCEPT);
  677         INP_WUNLOCK(inp);
  678         INP_INFO_RUNLOCK(&V_tcbinfo);
  679         if (error == 0)
  680                 *nam = in_sockaddr(port, &addr);
  681         return error;
  682 }
  683 #endif /* INET */
  684 
  685 #ifdef INET6
  686 static int
  687 tcp6_usr_accept(struct socket *so, struct sockaddr **nam)
  688 {
  689         struct inpcb *inp = NULL;
  690         int error = 0;
  691         struct tcpcb *tp = NULL;
  692         struct in_addr addr;
  693         struct in6_addr addr6;
  694         in_port_t port = 0;
  695         int v4 = 0;
  696         TCPDEBUG0;
  697 
  698         if (so->so_state & SS_ISDISCONNECTED)
  699                 return (ECONNABORTED);
  700 
  701         inp = sotoinpcb(so);
  702         KASSERT(inp != NULL, ("tcp6_usr_accept: inp == NULL"));
  703         INP_INFO_RLOCK(&V_tcbinfo);
  704         INP_WLOCK(inp);
  705         if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
  706                 error = ECONNABORTED;
  707                 goto out;
  708         }
  709         tp = intotcpcb(inp);
  710         TCPDEBUG1();
  711 
  712         /*
  713          * We inline in6_mapped_peeraddr and COMMON_END here, so that we can
  714          * copy the data of interest and defer the malloc until after we
  715          * release the lock.
  716          */
  717         if (inp->inp_vflag & INP_IPV4) {
  718                 v4 = 1;
  719                 port = inp->inp_fport;
  720                 addr = inp->inp_faddr;
  721         } else {
  722                 port = inp->inp_fport;
  723                 addr6 = inp->in6p_faddr;
  724         }
  725 
  726 out:
  727         TCPDEBUG2(PRU_ACCEPT);
  728         INP_WUNLOCK(inp);
  729         INP_INFO_RUNLOCK(&V_tcbinfo);
  730         if (error == 0) {
  731                 if (v4)
  732                         *nam = in6_v4mapsin6_sockaddr(port, &addr);
  733                 else
  734                         *nam = in6_sockaddr(port, &addr6);
  735         }
  736         return error;
  737 }
  738 #endif /* INET6 */
  739 
  740 /*
  741  * Mark the connection as being incapable of further output.
  742  */
  743 static int
  744 tcp_usr_shutdown(struct socket *so)
  745 {
  746         int error = 0;
  747         struct inpcb *inp;
  748         struct tcpcb *tp = NULL;
  749 
  750         TCPDEBUG0;
  751         INP_INFO_WLOCK(&V_tcbinfo);
  752         inp = sotoinpcb(so);
  753         KASSERT(inp != NULL, ("inp == NULL"));
  754         INP_WLOCK(inp);
  755         if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
  756                 error = ECONNRESET;
  757                 goto out;
  758         }
  759         tp = intotcpcb(inp);
  760         TCPDEBUG1();
  761         socantsendmore(so);
  762         tcp_usrclosed(tp);
  763         if (!(inp->inp_flags & INP_DROPPED))
  764                 error = tcp_output(tp);
  765 
  766 out:
  767         TCPDEBUG2(PRU_SHUTDOWN);
  768         INP_WUNLOCK(inp);
  769         INP_INFO_WUNLOCK(&V_tcbinfo);
  770 
  771         return (error);
  772 }
  773 
  774 /*
  775  * After a receive, possibly send window update to peer.
  776  */
  777 static int
  778 tcp_usr_rcvd(struct socket *so, int flags)
  779 {
  780         struct inpcb *inp;
  781         struct tcpcb *tp = NULL;
  782         int error = 0;
  783 
  784         TCPDEBUG0;
  785         inp = sotoinpcb(so);
  786         KASSERT(inp != NULL, ("tcp_usr_rcvd: inp == NULL"));
  787         INP_WLOCK(inp);
  788         if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
  789                 error = ECONNRESET;
  790                 goto out;
  791         }
  792         tp = intotcpcb(inp);
  793         TCPDEBUG1();
  794 #ifdef TCP_OFFLOAD
  795         if (tp->t_flags & TF_TOE)
  796                 tcp_offload_rcvd(tp);
  797         else
  798 #endif
  799         tcp_output(tp);
  800 
  801 out:
  802         TCPDEBUG2(PRU_RCVD);
  803         INP_WUNLOCK(inp);
  804         return (error);
  805 }
  806 
  807 /*
  808  * Do a send by putting data in output queue and updating urgent
  809  * marker if URG set.  Possibly send more data.  Unlike the other
  810  * pru_*() routines, the mbuf chains are our responsibility.  We
  811  * must either enqueue them or free them.  The other pru_* routines
  812  * generally are caller-frees.
  813  */
  814 static int
  815 tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
  816     struct sockaddr *nam, struct mbuf *control, struct thread *td)
  817 {
  818         int error = 0;
  819         struct inpcb *inp;
  820         struct tcpcb *tp = NULL;
  821 #ifdef INET6
  822         int isipv6;
  823 #endif
  824         TCPDEBUG0;
  825 
  826         /*
  827          * We require the pcbinfo lock if we will close the socket as part of
  828          * this call.
  829          */
  830         if (flags & PRUS_EOF)
  831                 INP_INFO_WLOCK(&V_tcbinfo);
  832         inp = sotoinpcb(so);
  833         KASSERT(inp != NULL, ("tcp_usr_send: inp == NULL"));
  834         INP_WLOCK(inp);
  835         if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
  836                 if (control)
  837                         m_freem(control);
  838                 if (m)
  839                         m_freem(m);
  840                 error = ECONNRESET;
  841                 goto out;
  842         }
  843 #ifdef INET6
  844         isipv6 = nam && nam->sa_family == AF_INET6;
  845 #endif /* INET6 */
  846         tp = intotcpcb(inp);
  847         TCPDEBUG1();
  848         if (control) {
  849                 /* TCP doesn't do control messages (rights, creds, etc) */
  850                 if (control->m_len) {
  851                         m_freem(control);
  852                         if (m)
  853                                 m_freem(m);
  854                         error = EINVAL;
  855                         goto out;
  856                 }
  857                 m_freem(control);       /* empty control, just free it */
  858         }
  859         if (!(flags & PRUS_OOB)) {
  860                 sbappendstream(&so->so_snd, m);
  861                 if (nam && tp->t_state < TCPS_SYN_SENT) {
  862                         /*
  863                          * Do implied connect if not yet connected,
  864                          * initialize window to default value, and
  865                          * initialize maxseg/maxopd using peer's cached
  866                          * MSS.
  867                          */
  868 #ifdef INET6
  869                         if (isipv6)
  870                                 error = tcp6_connect(tp, nam, td);
  871 #endif /* INET6 */
  872 #if defined(INET6) && defined(INET)
  873                         else
  874 #endif
  875 #ifdef INET
  876                                 error = tcp_connect(tp, nam, td);
  877 #endif
  878                         if (error)
  879                                 goto out;
  880                         tp->snd_wnd = TTCP_CLIENT_SND_WND;
  881                         tcp_mss(tp, -1);
  882                 }
  883                 if (flags & PRUS_EOF) {
  884                         /*
  885                          * Close the send side of the connection after
  886                          * the data is sent.
  887                          */
  888                         INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
  889                         socantsendmore(so);
  890                         tcp_usrclosed(tp);
  891                 }
  892                 if (!(inp->inp_flags & INP_DROPPED)) {
  893                         if (flags & PRUS_MORETOCOME)
  894                                 tp->t_flags |= TF_MORETOCOME;
  895                         error = tcp_output(tp);
  896                         if (flags & PRUS_MORETOCOME)
  897                                 tp->t_flags &= ~TF_MORETOCOME;
  898                 }
  899         } else {
  900                 /*
  901                  * XXXRW: PRUS_EOF not implemented with PRUS_OOB?
  902                  */
  903                 SOCKBUF_LOCK(&so->so_snd);
  904                 if (sbspace(&so->so_snd) < -512) {
  905                         SOCKBUF_UNLOCK(&so->so_snd);
  906                         m_freem(m);
  907                         error = ENOBUFS;
  908                         goto out;
  909                 }
  910                 /*
  911                  * According to RFC961 (Assigned Protocols),
  912                  * the urgent pointer points to the last octet
  913                  * of urgent data.  We continue, however,
  914                  * to consider it to indicate the first octet
  915                  * of data past the urgent section.
  916                  * Otherwise, snd_up should be one lower.
  917                  */
  918                 sbappendstream_locked(&so->so_snd, m);
  919                 SOCKBUF_UNLOCK(&so->so_snd);
  920                 if (nam && tp->t_state < TCPS_SYN_SENT) {
  921                         /*
  922                          * Do implied connect if not yet connected,
  923                          * initialize window to default value, and
  924                          * initialize maxseg/maxopd using peer's cached
  925                          * MSS.
  926                          */
  927 #ifdef INET6
  928                         if (isipv6)
  929                                 error = tcp6_connect(tp, nam, td);
  930 #endif /* INET6 */
  931 #if defined(INET6) && defined(INET)
  932                         else
  933 #endif
  934 #ifdef INET
  935                                 error = tcp_connect(tp, nam, td);
  936 #endif
  937                         if (error)
  938                                 goto out;
  939                         tp->snd_wnd = TTCP_CLIENT_SND_WND;
  940                         tcp_mss(tp, -1);
  941                 }
  942                 tp->snd_up = tp->snd_una + so->so_snd.sb_cc;
  943                 tp->t_flags |= TF_FORCEDATA;
  944                 error = tcp_output(tp);
  945                 tp->t_flags &= ~TF_FORCEDATA;
  946         }
  947 out:
  948         TCPDEBUG2((flags & PRUS_OOB) ? PRU_SENDOOB :
  949                   ((flags & PRUS_EOF) ? PRU_SEND_EOF : PRU_SEND));
  950         INP_WUNLOCK(inp);
  951         if (flags & PRUS_EOF)
  952                 INP_INFO_WUNLOCK(&V_tcbinfo);
  953         return (error);
  954 }
  955 
  956 /*
  957  * Abort the TCP.  Drop the connection abruptly.
  958  */
  959 static void
  960 tcp_usr_abort(struct socket *so)
  961 {
  962         struct inpcb *inp;
  963         struct tcpcb *tp = NULL;
  964         TCPDEBUG0;
  965 
  966         inp = sotoinpcb(so);
  967         KASSERT(inp != NULL, ("tcp_usr_abort: inp == NULL"));
  968 
  969         INP_INFO_WLOCK(&V_tcbinfo);
  970         INP_WLOCK(inp);
  971         KASSERT(inp->inp_socket != NULL,
  972             ("tcp_usr_abort: inp_socket == NULL"));
  973 
  974         /*
  975          * If we still have full TCP state, and we're not dropped, drop.
  976          */
  977         if (!(inp->inp_flags & INP_TIMEWAIT) &&
  978             !(inp->inp_flags & INP_DROPPED)) {
  979                 tp = intotcpcb(inp);
  980                 TCPDEBUG1();
  981                 tcp_drop(tp, ECONNABORTED);
  982                 TCPDEBUG2(PRU_ABORT);
  983         }
  984         if (!(inp->inp_flags & INP_DROPPED)) {
  985                 SOCK_LOCK(so);
  986                 so->so_state |= SS_PROTOREF;
  987                 SOCK_UNLOCK(so);
  988                 inp->inp_flags |= INP_SOCKREF;
  989         }
  990         INP_WUNLOCK(inp);
  991         INP_INFO_WUNLOCK(&V_tcbinfo);
  992 }
  993 
  994 /*
  995  * TCP socket is closed.  Start friendly disconnect.
  996  */
  997 static void
  998 tcp_usr_close(struct socket *so)
  999 {
 1000         struct inpcb *inp;
 1001         struct tcpcb *tp = NULL;
 1002         TCPDEBUG0;
 1003 
 1004         inp = sotoinpcb(so);
 1005         KASSERT(inp != NULL, ("tcp_usr_close: inp == NULL"));
 1006 
 1007         INP_INFO_WLOCK(&V_tcbinfo);
 1008         INP_WLOCK(inp);
 1009         KASSERT(inp->inp_socket != NULL,
 1010             ("tcp_usr_close: inp_socket == NULL"));
 1011 
 1012         /*
 1013          * If we still have full TCP state, and we're not dropped, initiate
 1014          * a disconnect.
 1015          */
 1016         if (!(inp->inp_flags & INP_TIMEWAIT) &&
 1017             !(inp->inp_flags & INP_DROPPED)) {
 1018                 tp = intotcpcb(inp);
 1019                 TCPDEBUG1();
 1020                 tcp_disconnect(tp);
 1021                 TCPDEBUG2(PRU_CLOSE);
 1022         }
 1023         if (!(inp->inp_flags & INP_DROPPED)) {
 1024                 SOCK_LOCK(so);
 1025                 so->so_state |= SS_PROTOREF;
 1026                 SOCK_UNLOCK(so);
 1027                 inp->inp_flags |= INP_SOCKREF;
 1028         }
 1029         INP_WUNLOCK(inp);
 1030         INP_INFO_WUNLOCK(&V_tcbinfo);
 1031 }
 1032 
 1033 /*
 1034  * Receive out-of-band data.
 1035  */
 1036 static int
 1037 tcp_usr_rcvoob(struct socket *so, struct mbuf *m, int flags)
 1038 {
 1039         int error = 0;
 1040         struct inpcb *inp;
 1041         struct tcpcb *tp = NULL;
 1042 
 1043         TCPDEBUG0;
 1044         inp = sotoinpcb(so);
 1045         KASSERT(inp != NULL, ("tcp_usr_rcvoob: inp == NULL"));
 1046         INP_WLOCK(inp);
 1047         if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
 1048                 error = ECONNRESET;
 1049                 goto out;
 1050         }
 1051         tp = intotcpcb(inp);
 1052         TCPDEBUG1();
 1053         if ((so->so_oobmark == 0 &&
 1054              (so->so_rcv.sb_state & SBS_RCVATMARK) == 0) ||
 1055             so->so_options & SO_OOBINLINE ||
 1056             tp->t_oobflags & TCPOOB_HADDATA) {
 1057                 error = EINVAL;
 1058                 goto out;
 1059         }
 1060         if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
 1061                 error = EWOULDBLOCK;
 1062                 goto out;
 1063         }
 1064         m->m_len = 1;
 1065         *mtod(m, caddr_t) = tp->t_iobc;
 1066         if ((flags & MSG_PEEK) == 0)
 1067                 tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA);
 1068 
 1069 out:
 1070         TCPDEBUG2(PRU_RCVOOB);
 1071         INP_WUNLOCK(inp);
 1072         return (error);
 1073 }
 1074 
 1075 #ifdef INET
 1076 struct pr_usrreqs tcp_usrreqs = {
 1077         .pru_abort =            tcp_usr_abort,
 1078         .pru_accept =           tcp_usr_accept,
 1079         .pru_attach =           tcp_usr_attach,
 1080         .pru_bind =             tcp_usr_bind,
 1081         .pru_connect =          tcp_usr_connect,
 1082         .pru_control =          in_control,
 1083         .pru_detach =           tcp_usr_detach,
 1084         .pru_disconnect =       tcp_usr_disconnect,
 1085         .pru_listen =           tcp_usr_listen,
 1086         .pru_peeraddr =         in_getpeeraddr,
 1087         .pru_rcvd =             tcp_usr_rcvd,
 1088         .pru_rcvoob =           tcp_usr_rcvoob,
 1089         .pru_send =             tcp_usr_send,
 1090         .pru_shutdown =         tcp_usr_shutdown,
 1091         .pru_sockaddr =         in_getsockaddr,
 1092         .pru_sosetlabel =       in_pcbsosetlabel,
 1093         .pru_close =            tcp_usr_close,
 1094 };
 1095 #endif /* INET */
 1096 
 1097 #ifdef INET6
 1098 struct pr_usrreqs tcp6_usrreqs = {
 1099         .pru_abort =            tcp_usr_abort,
 1100         .pru_accept =           tcp6_usr_accept,
 1101         .pru_attach =           tcp_usr_attach,
 1102         .pru_bind =             tcp6_usr_bind,
 1103         .pru_connect =          tcp6_usr_connect,
 1104         .pru_control =          in6_control,
 1105         .pru_detach =           tcp_usr_detach,
 1106         .pru_disconnect =       tcp_usr_disconnect,
 1107         .pru_listen =           tcp6_usr_listen,
 1108         .pru_peeraddr =         in6_mapped_peeraddr,
 1109         .pru_rcvd =             tcp_usr_rcvd,
 1110         .pru_rcvoob =           tcp_usr_rcvoob,
 1111         .pru_send =             tcp_usr_send,
 1112         .pru_shutdown =         tcp_usr_shutdown,
 1113         .pru_sockaddr =         in6_mapped_sockaddr,
 1114         .pru_sosetlabel =       in_pcbsosetlabel,
 1115         .pru_close =            tcp_usr_close,
 1116 };
 1117 #endif /* INET6 */
 1118 
 1119 #ifdef INET
 1120 /*
 1121  * Common subroutine to open a TCP connection to remote host specified
 1122  * by struct sockaddr_in in mbuf *nam.  Call in_pcbbind to assign a local
 1123  * port number if needed.  Call in_pcbconnect_setup to do the routing and
 1124  * to choose a local host address (interface).  If there is an existing
 1125  * incarnation of the same connection in TIME-WAIT state and if the remote
 1126  * host was sending CC options and if the connection duration was < MSL, then
 1127  * truncate the previous TIME-WAIT state and proceed.
 1128  * Initialize connection parameters and enter SYN-SENT state.
 1129  */
 1130 static int
 1131 tcp_connect(struct tcpcb *tp, struct sockaddr *nam, struct thread *td)
 1132 {
 1133         struct inpcb *inp = tp->t_inpcb, *oinp;
 1134         struct socket *so = inp->inp_socket;
 1135         struct in_addr laddr;
 1136         u_short lport;
 1137         int error;
 1138 
 1139         INP_WLOCK_ASSERT(inp);
 1140         INP_HASH_WLOCK(&V_tcbinfo);
 1141 
 1142         if (inp->inp_lport == 0) {
 1143                 error = in_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
 1144                 if (error)
 1145                         goto out;
 1146         }
 1147 
 1148         /*
 1149          * Cannot simply call in_pcbconnect, because there might be an
 1150          * earlier incarnation of this same connection still in
 1151          * TIME_WAIT state, creating an ADDRINUSE error.
 1152          */
 1153         laddr = inp->inp_laddr;
 1154         lport = inp->inp_lport;
 1155         error = in_pcbconnect_setup(inp, nam, &laddr.s_addr, &lport,
 1156             &inp->inp_faddr.s_addr, &inp->inp_fport, &oinp, td->td_ucred);
 1157         if (error && oinp == NULL)
 1158                 goto out;
 1159         if (oinp) {
 1160                 error = EADDRINUSE;
 1161                 goto out;
 1162         }
 1163         inp->inp_laddr = laddr;
 1164         in_pcbrehash(inp);
 1165         INP_HASH_WUNLOCK(&V_tcbinfo);
 1166 
 1167         /*
 1168          * Compute window scaling to request:
 1169          * Scale to fit into sweet spot.  See tcp_syncache.c.
 1170          * XXX: This should move to tcp_output().
 1171          */
 1172         while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
 1173             (TCP_MAXWIN << tp->request_r_scale) < sb_max)
 1174                 tp->request_r_scale++;
 1175 
 1176         soisconnecting(so);
 1177         TCPSTAT_INC(tcps_connattempt);
 1178         tcp_state_change(tp, TCPS_SYN_SENT);
 1179         tp->iss = tcp_new_isn(tp);
 1180         tcp_sendseqinit(tp);
 1181 
 1182         return 0;
 1183 
 1184 out:
 1185         INP_HASH_WUNLOCK(&V_tcbinfo);
 1186         return (error);
 1187 }
 1188 #endif /* INET */
 1189 
 1190 #ifdef INET6
 1191 static int
 1192 tcp6_connect(struct tcpcb *tp, struct sockaddr *nam, struct thread *td)
 1193 {
 1194         struct inpcb *inp = tp->t_inpcb, *oinp;
 1195         struct socket *so = inp->inp_socket;
 1196         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)nam;
 1197         struct in6_addr addr6;
 1198         int error;
 1199 
 1200         INP_WLOCK_ASSERT(inp);
 1201         INP_HASH_WLOCK(&V_tcbinfo);
 1202 
 1203         if (inp->inp_lport == 0) {
 1204                 error = in6_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
 1205                 if (error)
 1206                         goto out;
 1207         }
 1208 
 1209         /*
 1210          * Cannot simply call in_pcbconnect, because there might be an
 1211          * earlier incarnation of this same connection still in
 1212          * TIME_WAIT state, creating an ADDRINUSE error.
 1213          * in6_pcbladdr() also handles scope zone IDs.
 1214          *
 1215          * XXXRW: We wouldn't need to expose in6_pcblookup_hash_locked()
 1216          * outside of in6_pcb.c if there were an in6_pcbconnect_setup().
 1217          */
 1218         error = in6_pcbladdr(inp, nam, &addr6);
 1219         if (error)
 1220                 goto out;
 1221         oinp = in6_pcblookup_hash_locked(inp->inp_pcbinfo,
 1222                                   &sin6->sin6_addr, sin6->sin6_port,
 1223                                   IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)
 1224                                   ? &addr6
 1225                                   : &inp->in6p_laddr,
 1226                                   inp->inp_lport,  0, NULL);
 1227         if (oinp) {
 1228                 error = EADDRINUSE;
 1229                 goto out;
 1230         }
 1231         if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr))
 1232                 inp->in6p_laddr = addr6;
 1233         inp->in6p_faddr = sin6->sin6_addr;
 1234         inp->inp_fport = sin6->sin6_port;
 1235         /* update flowinfo - draft-itojun-ipv6-flowlabel-api-00 */
 1236         inp->inp_flow &= ~IPV6_FLOWLABEL_MASK;
 1237         if (inp->inp_flags & IN6P_AUTOFLOWLABEL)
 1238                 inp->inp_flow |=
 1239                     (htonl(ip6_randomflowlabel()) & IPV6_FLOWLABEL_MASK);
 1240         in_pcbrehash(inp);
 1241         INP_HASH_WUNLOCK(&V_tcbinfo);
 1242 
 1243         /* Compute window scaling to request.  */
 1244         while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
 1245             (TCP_MAXWIN << tp->request_r_scale) < sb_max)
 1246                 tp->request_r_scale++;
 1247 
 1248         soisconnecting(so);
 1249         TCPSTAT_INC(tcps_connattempt);
 1250         tcp_state_change(tp, TCPS_SYN_SENT);
 1251         tp->iss = tcp_new_isn(tp);
 1252         tcp_sendseqinit(tp);
 1253 
 1254         return 0;
 1255 
 1256 out:
 1257         INP_HASH_WUNLOCK(&V_tcbinfo);
 1258         return error;
 1259 }
 1260 #endif /* INET6 */
 1261 
 1262 /*
 1263  * Export TCP internal state information via a struct tcp_info, based on the
 1264  * Linux 2.6 API.  Not ABI compatible as our constants are mapped differently
 1265  * (TCP state machine, etc).  We export all information using FreeBSD-native
 1266  * constants -- for example, the numeric values for tcpi_state will differ
 1267  * from Linux.
 1268  */
 1269 static void
 1270 tcp_fill_info(struct tcpcb *tp, struct tcp_info *ti)
 1271 {
 1272 
 1273         INP_WLOCK_ASSERT(tp->t_inpcb);
 1274         bzero(ti, sizeof(*ti));
 1275 
 1276         ti->tcpi_state = tp->t_state;
 1277         if ((tp->t_flags & TF_REQ_TSTMP) && (tp->t_flags & TF_RCVD_TSTMP))
 1278                 ti->tcpi_options |= TCPI_OPT_TIMESTAMPS;
 1279         if (tp->t_flags & TF_SACK_PERMIT)
 1280                 ti->tcpi_options |= TCPI_OPT_SACK;
 1281         if ((tp->t_flags & TF_REQ_SCALE) && (tp->t_flags & TF_RCVD_SCALE)) {
 1282                 ti->tcpi_options |= TCPI_OPT_WSCALE;
 1283                 ti->tcpi_snd_wscale = tp->snd_scale;
 1284                 ti->tcpi_rcv_wscale = tp->rcv_scale;
 1285         }
 1286 
 1287         ti->tcpi_rto = tp->t_rxtcur * tick;
 1288         ti->tcpi_last_data_recv = (long)(ticks - (int)tp->t_rcvtime) * tick;
 1289         ti->tcpi_rtt = ((u_int64_t)tp->t_srtt * tick) >> TCP_RTT_SHIFT;
 1290         ti->tcpi_rttvar = ((u_int64_t)tp->t_rttvar * tick) >> TCP_RTTVAR_SHIFT;
 1291 
 1292         ti->tcpi_snd_ssthresh = tp->snd_ssthresh;
 1293         ti->tcpi_snd_cwnd = tp->snd_cwnd;
 1294 
 1295         /*
 1296          * FreeBSD-specific extension fields for tcp_info.
 1297          */
 1298         ti->tcpi_rcv_space = tp->rcv_wnd;
 1299         ti->tcpi_rcv_nxt = tp->rcv_nxt;
 1300         ti->tcpi_snd_wnd = tp->snd_wnd;
 1301         ti->tcpi_snd_bwnd = 0;          /* Unused, kept for compat. */
 1302         ti->tcpi_snd_nxt = tp->snd_nxt;
 1303         ti->tcpi_snd_mss = tp->t_maxseg;
 1304         ti->tcpi_rcv_mss = tp->t_maxseg;
 1305         if (tp->t_flags & TF_TOE)
 1306                 ti->tcpi_options |= TCPI_OPT_TOE;
 1307         ti->tcpi_snd_rexmitpack = tp->t_sndrexmitpack;
 1308         ti->tcpi_rcv_ooopack = tp->t_rcvoopack;
 1309         ti->tcpi_snd_zerowin = tp->t_sndzerowin;
 1310 }
 1311 
 1312 /*
 1313  * tcp_ctloutput() must drop the inpcb lock before performing copyin on
 1314  * socket option arguments.  When it re-acquires the lock after the copy, it
 1315  * has to revalidate that the connection is still valid for the socket
 1316  * option.
 1317  */
 1318 #define INP_WLOCK_RECHECK(inp) do {                                     \
 1319         INP_WLOCK(inp);                                                 \
 1320         if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {            \
 1321                 INP_WUNLOCK(inp);                                       \
 1322                 return (ECONNRESET);                                    \
 1323         }                                                               \
 1324         tp = intotcpcb(inp);                                            \
 1325 } while(0)
 1326 
 1327 int
 1328 tcp_ctloutput(struct socket *so, struct sockopt *sopt)
 1329 {
 1330         int     error, opt, optval;
 1331         u_int   ui;
 1332         struct  inpcb *inp;
 1333         struct  tcpcb *tp;
 1334         struct  tcp_info ti;
 1335         char buf[TCP_CA_NAME_MAX];
 1336         struct cc_algo *algo;
 1337 
 1338         error = 0;
 1339         inp = sotoinpcb(so);
 1340         KASSERT(inp != NULL, ("tcp_ctloutput: inp == NULL"));
 1341         INP_WLOCK(inp);
 1342         if (sopt->sopt_level != IPPROTO_TCP) {
 1343 #ifdef INET6
 1344                 if (inp->inp_vflag & INP_IPV6PROTO) {
 1345                         INP_WUNLOCK(inp);
 1346                         error = ip6_ctloutput(so, sopt);
 1347                 }
 1348 #endif /* INET6 */
 1349 #if defined(INET6) && defined(INET)
 1350                 else
 1351 #endif
 1352 #ifdef INET
 1353                 {
 1354                         INP_WUNLOCK(inp);
 1355                         error = ip_ctloutput(so, sopt);
 1356                 }
 1357 #endif
 1358                 return (error);
 1359         }
 1360         if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
 1361                 INP_WUNLOCK(inp);
 1362                 return (ECONNRESET);
 1363         }
 1364 
 1365         switch (sopt->sopt_dir) {
 1366         case SOPT_SET:
 1367                 switch (sopt->sopt_name) {
 1368 #ifdef TCP_SIGNATURE
 1369                 case TCP_MD5SIG:
 1370                         INP_WUNLOCK(inp);
 1371                         error = sooptcopyin(sopt, &optval, sizeof optval,
 1372                             sizeof optval);
 1373                         if (error)
 1374                                 return (error);
 1375 
 1376                         INP_WLOCK_RECHECK(inp);
 1377                         if (optval > 0)
 1378                                 tp->t_flags |= TF_SIGNATURE;
 1379                         else
 1380                                 tp->t_flags &= ~TF_SIGNATURE;
 1381                         goto unlock_and_done;
 1382 #endif /* TCP_SIGNATURE */
 1383 
 1384                 case TCP_NODELAY:
 1385                 case TCP_NOOPT:
 1386                         INP_WUNLOCK(inp);
 1387                         error = sooptcopyin(sopt, &optval, sizeof optval,
 1388                             sizeof optval);
 1389                         if (error)
 1390                                 return (error);
 1391 
 1392                         INP_WLOCK_RECHECK(inp);
 1393                         switch (sopt->sopt_name) {
 1394                         case TCP_NODELAY:
 1395                                 opt = TF_NODELAY;
 1396                                 break;
 1397                         case TCP_NOOPT:
 1398                                 opt = TF_NOOPT;
 1399                                 break;
 1400                         default:
 1401                                 opt = 0; /* dead code to fool gcc */
 1402                                 break;
 1403                         }
 1404 
 1405                         if (optval)
 1406                                 tp->t_flags |= opt;
 1407                         else
 1408                                 tp->t_flags &= ~opt;
 1409 unlock_and_done:
 1410 #ifdef TCP_OFFLOAD
 1411                         if (tp->t_flags & TF_TOE) {
 1412                                 tcp_offload_ctloutput(tp, sopt->sopt_dir,
 1413                                     sopt->sopt_name);
 1414                         }
 1415 #endif
 1416                         INP_WUNLOCK(inp);
 1417                         break;
 1418 
 1419                 case TCP_NOPUSH:
 1420                         INP_WUNLOCK(inp);
 1421                         error = sooptcopyin(sopt, &optval, sizeof optval,
 1422                             sizeof optval);
 1423                         if (error)
 1424                                 return (error);
 1425 
 1426                         INP_WLOCK_RECHECK(inp);
 1427                         if (optval)
 1428                                 tp->t_flags |= TF_NOPUSH;
 1429                         else if (tp->t_flags & TF_NOPUSH) {
 1430                                 tp->t_flags &= ~TF_NOPUSH;
 1431                                 if (TCPS_HAVEESTABLISHED(tp->t_state))
 1432                                         error = tcp_output(tp);
 1433                         }
 1434                         goto unlock_and_done;
 1435 
 1436                 case TCP_MAXSEG:
 1437                         INP_WUNLOCK(inp);
 1438                         error = sooptcopyin(sopt, &optval, sizeof optval,
 1439                             sizeof optval);
 1440                         if (error)
 1441                                 return (error);
 1442 
 1443                         INP_WLOCK_RECHECK(inp);
 1444                         if (optval > 0 && optval <= tp->t_maxseg &&
 1445                             optval + 40 >= V_tcp_minmss)
 1446                                 tp->t_maxseg = optval;
 1447                         else
 1448                                 error = EINVAL;
 1449                         goto unlock_and_done;
 1450 
 1451                 case TCP_INFO:
 1452                         INP_WUNLOCK(inp);
 1453                         error = EINVAL;
 1454                         break;
 1455 
 1456                 case TCP_CONGESTION:
 1457                         INP_WUNLOCK(inp);
 1458                         bzero(buf, sizeof(buf));
 1459                         error = sooptcopyin(sopt, &buf, sizeof(buf), 1);
 1460                         if (error)
 1461                                 break;
 1462                         INP_WLOCK_RECHECK(inp);
 1463                         /*
 1464                          * Return EINVAL if we can't find the requested cc algo.
 1465                          */
 1466                         error = EINVAL;
 1467                         CC_LIST_RLOCK();
 1468                         STAILQ_FOREACH(algo, &cc_list, entries) {
 1469                                 if (strncmp(buf, algo->name, TCP_CA_NAME_MAX)
 1470                                     == 0) {
 1471                                         /* We've found the requested algo. */
 1472                                         error = 0;
 1473                                         /*
 1474                                          * We hold a write lock over the tcb
 1475                                          * so it's safe to do these things
 1476                                          * without ordering concerns.
 1477                                          */
 1478                                         if (CC_ALGO(tp)->cb_destroy != NULL)
 1479                                                 CC_ALGO(tp)->cb_destroy(tp->ccv);
 1480                                         CC_ALGO(tp) = algo;
 1481                                         /*
 1482                                          * If something goes pear shaped
 1483                                          * initialising the new algo,
 1484                                          * fall back to newreno (which
 1485                                          * does not require initialisation).
 1486                                          */
 1487                                         if (algo->cb_init != NULL)
 1488                                                 if (algo->cb_init(tp->ccv) > 0) {
 1489                                                         CC_ALGO(tp) = &newreno_cc_algo;
 1490                                                         /*
 1491                                                          * The only reason init
 1492                                                          * should fail is
 1493                                                          * because of malloc.
 1494                                                          */
 1495                                                         error = ENOMEM;
 1496                                                 }
 1497                                         break; /* Break the STAILQ_FOREACH. */
 1498                                 }
 1499                         }
 1500                         CC_LIST_RUNLOCK();
 1501                         goto unlock_and_done;
 1502 
 1503                 case TCP_KEEPIDLE:
 1504                 case TCP_KEEPINTVL:
 1505                 case TCP_KEEPINIT:
 1506                         INP_WUNLOCK(inp);
 1507                         error = sooptcopyin(sopt, &ui, sizeof(ui), sizeof(ui));
 1508                         if (error)
 1509                                 return (error);
 1510 
 1511                         if (ui > (UINT_MAX / hz)) {
 1512                                 error = EINVAL;
 1513                                 break;
 1514                         }
 1515                         ui *= hz;
 1516 
 1517                         INP_WLOCK_RECHECK(inp);
 1518                         switch (sopt->sopt_name) {
 1519                         case TCP_KEEPIDLE:
 1520                                 tp->t_keepidle = ui;
 1521                                 /*
 1522                                  * XXX: better check current remaining
 1523                                  * timeout and "merge" it with new value.
 1524                                  */
 1525                                 if ((tp->t_state > TCPS_LISTEN) &&
 1526                                     (tp->t_state <= TCPS_CLOSING))
 1527                                         tcp_timer_activate(tp, TT_KEEP,
 1528                                             TP_KEEPIDLE(tp));
 1529                                 break;
 1530                         case TCP_KEEPINTVL:
 1531                                 tp->t_keepintvl = ui;
 1532                                 if ((tp->t_state == TCPS_FIN_WAIT_2) &&
 1533                                     (TP_MAXIDLE(tp) > 0))
 1534                                         tcp_timer_activate(tp, TT_2MSL,
 1535                                             TP_MAXIDLE(tp));
 1536                                 break;
 1537                         case TCP_KEEPINIT:
 1538                                 tp->t_keepinit = ui;
 1539                                 if (tp->t_state == TCPS_SYN_RECEIVED ||
 1540                                     tp->t_state == TCPS_SYN_SENT)
 1541                                         tcp_timer_activate(tp, TT_KEEP,
 1542                                             TP_KEEPINIT(tp));
 1543                                 break;
 1544                         }
 1545                         goto unlock_and_done;
 1546 
 1547                 case TCP_KEEPCNT:
 1548                         INP_WUNLOCK(inp);
 1549                         error = sooptcopyin(sopt, &ui, sizeof(ui), sizeof(ui));
 1550                         if (error)
 1551                                 return (error);
 1552 
 1553                         INP_WLOCK_RECHECK(inp);
 1554                         tp->t_keepcnt = ui;
 1555                         if ((tp->t_state == TCPS_FIN_WAIT_2) &&
 1556                             (TP_MAXIDLE(tp) > 0))
 1557                                 tcp_timer_activate(tp, TT_2MSL,
 1558                                     TP_MAXIDLE(tp));
 1559                         goto unlock_and_done;
 1560 
 1561                 default:
 1562                         INP_WUNLOCK(inp);
 1563                         error = ENOPROTOOPT;
 1564                         break;
 1565                 }
 1566                 break;
 1567 
 1568         case SOPT_GET:
 1569                 tp = intotcpcb(inp);
 1570                 switch (sopt->sopt_name) {
 1571 #ifdef TCP_SIGNATURE
 1572                 case TCP_MD5SIG:
 1573                         optval = (tp->t_flags & TF_SIGNATURE) ? 1 : 0;
 1574                         INP_WUNLOCK(inp);
 1575                         error = sooptcopyout(sopt, &optval, sizeof optval);
 1576                         break;
 1577 #endif
 1578 
 1579                 case TCP_NODELAY:
 1580                         optval = tp->t_flags & TF_NODELAY;
 1581                         INP_WUNLOCK(inp);
 1582                         error = sooptcopyout(sopt, &optval, sizeof optval);
 1583                         break;
 1584                 case TCP_MAXSEG:
 1585                         optval = tp->t_maxseg;
 1586                         INP_WUNLOCK(inp);
 1587                         error = sooptcopyout(sopt, &optval, sizeof optval);
 1588                         break;
 1589                 case TCP_NOOPT:
 1590                         optval = tp->t_flags & TF_NOOPT;
 1591                         INP_WUNLOCK(inp);
 1592                         error = sooptcopyout(sopt, &optval, sizeof optval);
 1593                         break;
 1594                 case TCP_NOPUSH:
 1595                         optval = tp->t_flags & TF_NOPUSH;
 1596                         INP_WUNLOCK(inp);
 1597                         error = sooptcopyout(sopt, &optval, sizeof optval);
 1598                         break;
 1599                 case TCP_INFO:
 1600                         tcp_fill_info(tp, &ti);
 1601                         INP_WUNLOCK(inp);
 1602                         error = sooptcopyout(sopt, &ti, sizeof ti);
 1603                         break;
 1604                 case TCP_CONGESTION:
 1605                         bzero(buf, sizeof(buf));
 1606                         strlcpy(buf, CC_ALGO(tp)->name, TCP_CA_NAME_MAX);
 1607                         INP_WUNLOCK(inp);
 1608                         error = sooptcopyout(sopt, buf, TCP_CA_NAME_MAX);
 1609                         break;
 1610                 case TCP_KEEPIDLE:
 1611                 case TCP_KEEPINTVL:
 1612                 case TCP_KEEPINIT:
 1613                 case TCP_KEEPCNT:
 1614                         switch (sopt->sopt_name) {
 1615                         case TCP_KEEPIDLE:
 1616                                 ui = tp->t_keepidle / hz;
 1617                                 break;
 1618                         case TCP_KEEPINTVL:
 1619                                 ui = tp->t_keepintvl / hz;
 1620                                 break;
 1621                         case TCP_KEEPINIT:
 1622                                 ui = tp->t_keepinit / hz;
 1623                                 break;
 1624                         case TCP_KEEPCNT:
 1625                                 ui = tp->t_keepcnt;
 1626                                 break;
 1627                         }
 1628                         INP_WUNLOCK(inp);
 1629                         error = sooptcopyout(sopt, &ui, sizeof(ui));
 1630                         break;
 1631                 default:
 1632                         INP_WUNLOCK(inp);
 1633                         error = ENOPROTOOPT;
 1634                         break;
 1635                 }
 1636                 break;
 1637         }
 1638         return (error);
 1639 }
 1640 #undef INP_WLOCK_RECHECK
 1641 
 1642 /*
 1643  * Attach TCP protocol to socket, allocating
 1644  * internet protocol control block, tcp control block,
 1645  * bufer space, and entering LISTEN state if to accept connections.
 1646  */
 1647 static int
 1648 tcp_attach(struct socket *so)
 1649 {
 1650         struct tcpcb *tp;
 1651         struct inpcb *inp;
 1652         int error;
 1653 
 1654         if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
 1655                 error = soreserve(so, V_tcp_sendspace, V_tcp_recvspace);
 1656                 if (error)
 1657                         return (error);
 1658         }
 1659         so->so_rcv.sb_flags |= SB_AUTOSIZE;
 1660         so->so_snd.sb_flags |= SB_AUTOSIZE;
 1661         INP_INFO_WLOCK(&V_tcbinfo);
 1662         error = in_pcballoc(so, &V_tcbinfo);
 1663         if (error) {
 1664                 INP_INFO_WUNLOCK(&V_tcbinfo);
 1665                 return (error);
 1666         }
 1667         inp = sotoinpcb(so);
 1668 #ifdef INET6
 1669         if (inp->inp_vflag & INP_IPV6PROTO) {
 1670                 inp->inp_vflag |= INP_IPV6;
 1671                 inp->in6p_hops = -1;    /* use kernel default */
 1672         }
 1673         else
 1674 #endif
 1675         inp->inp_vflag |= INP_IPV4;
 1676         tp = tcp_newtcpcb(inp);
 1677         if (tp == NULL) {
 1678                 in_pcbdetach(inp);
 1679                 in_pcbfree(inp);
 1680                 INP_INFO_WUNLOCK(&V_tcbinfo);
 1681                 return (ENOBUFS);
 1682         }
 1683         tp->t_state = TCPS_CLOSED;
 1684         INP_WUNLOCK(inp);
 1685         INP_INFO_WUNLOCK(&V_tcbinfo);
 1686         return (0);
 1687 }
 1688 
 1689 /*
 1690  * Initiate (or continue) disconnect.
 1691  * If embryonic state, just send reset (once).
 1692  * If in ``let data drain'' option and linger null, just drop.
 1693  * Otherwise (hard), mark socket disconnecting and drop
 1694  * current input data; switch states based on user close, and
 1695  * send segment to peer (with FIN).
 1696  */
 1697 static void
 1698 tcp_disconnect(struct tcpcb *tp)
 1699 {
 1700         struct inpcb *inp = tp->t_inpcb;
 1701         struct socket *so = inp->inp_socket;
 1702 
 1703         INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
 1704         INP_WLOCK_ASSERT(inp);
 1705 
 1706         /*
 1707          * Neither tcp_close() nor tcp_drop() should return NULL, as the
 1708          * socket is still open.
 1709          */
 1710         if (tp->t_state < TCPS_ESTABLISHED) {
 1711                 tp = tcp_close(tp);
 1712                 KASSERT(tp != NULL,
 1713                     ("tcp_disconnect: tcp_close() returned NULL"));
 1714         } else if ((so->so_options & SO_LINGER) && so->so_linger == 0) {
 1715                 tp = tcp_drop(tp, 0);
 1716                 KASSERT(tp != NULL,
 1717                     ("tcp_disconnect: tcp_drop() returned NULL"));
 1718         } else {
 1719                 soisdisconnecting(so);
 1720                 sbflush(&so->so_rcv);
 1721                 tcp_usrclosed(tp);
 1722                 if (!(inp->inp_flags & INP_DROPPED))
 1723                         tcp_output(tp);
 1724         }
 1725 }
 1726 
 1727 /*
 1728  * User issued close, and wish to trail through shutdown states:
 1729  * if never received SYN, just forget it.  If got a SYN from peer,
 1730  * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
 1731  * If already got a FIN from peer, then almost done; go to LAST_ACK
 1732  * state.  In all other cases, have already sent FIN to peer (e.g.
 1733  * after PRU_SHUTDOWN), and just have to play tedious game waiting
 1734  * for peer to send FIN or not respond to keep-alives, etc.
 1735  * We can let the user exit from the close as soon as the FIN is acked.
 1736  */
 1737 static void
 1738 tcp_usrclosed(struct tcpcb *tp)
 1739 {
 1740 
 1741         INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
 1742         INP_WLOCK_ASSERT(tp->t_inpcb);
 1743 
 1744         switch (tp->t_state) {
 1745         case TCPS_LISTEN:
 1746 #ifdef TCP_OFFLOAD
 1747                 tcp_offload_listen_stop(tp);
 1748 #endif
 1749                 /* FALLTHROUGH */
 1750         case TCPS_CLOSED:
 1751                 tcp_state_change(tp, TCPS_CLOSED);
 1752                 tp = tcp_close(tp);
 1753                 /*
 1754                  * tcp_close() should never return NULL here as the socket is
 1755                  * still open.
 1756                  */
 1757                 KASSERT(tp != NULL,
 1758                     ("tcp_usrclosed: tcp_close() returned NULL"));
 1759                 break;
 1760 
 1761         case TCPS_SYN_SENT:
 1762         case TCPS_SYN_RECEIVED:
 1763                 tp->t_flags |= TF_NEEDFIN;
 1764                 break;
 1765 
 1766         case TCPS_ESTABLISHED:
 1767                 tcp_state_change(tp, TCPS_FIN_WAIT_1);
 1768                 break;
 1769 
 1770         case TCPS_CLOSE_WAIT:
 1771                 tcp_state_change(tp, TCPS_LAST_ACK);
 1772                 break;
 1773         }
 1774         if (tp->t_state >= TCPS_FIN_WAIT_2) {
 1775                 soisdisconnected(tp->t_inpcb->inp_socket);
 1776                 /* Prevent the connection hanging in FIN_WAIT_2 forever. */
 1777                 if (tp->t_state == TCPS_FIN_WAIT_2) {
 1778                         int timeout;
 1779 
 1780                         timeout = (tcp_fast_finwait2_recycle) ? 
 1781                             tcp_finwait2_timeout : TP_MAXIDLE(tp);
 1782                         tcp_timer_activate(tp, TT_2MSL, timeout);
 1783                 }
 1784         }
 1785 }
 1786 
 1787 #ifdef DDB
 1788 static void
 1789 db_print_indent(int indent)
 1790 {
 1791         int i;
 1792 
 1793         for (i = 0; i < indent; i++)
 1794                 db_printf(" ");
 1795 }
 1796 
 1797 static void
 1798 db_print_tstate(int t_state)
 1799 {
 1800 
 1801         switch (t_state) {
 1802         case TCPS_CLOSED:
 1803                 db_printf("TCPS_CLOSED");
 1804                 return;
 1805 
 1806         case TCPS_LISTEN:
 1807                 db_printf("TCPS_LISTEN");
 1808                 return;
 1809 
 1810         case TCPS_SYN_SENT:
 1811                 db_printf("TCPS_SYN_SENT");
 1812                 return;
 1813 
 1814         case TCPS_SYN_RECEIVED:
 1815                 db_printf("TCPS_SYN_RECEIVED");
 1816                 return;
 1817 
 1818         case TCPS_ESTABLISHED:
 1819                 db_printf("TCPS_ESTABLISHED");
 1820                 return;
 1821 
 1822         case TCPS_CLOSE_WAIT:
 1823                 db_printf("TCPS_CLOSE_WAIT");
 1824                 return;
 1825 
 1826         case TCPS_FIN_WAIT_1:
 1827                 db_printf("TCPS_FIN_WAIT_1");
 1828                 return;
 1829 
 1830         case TCPS_CLOSING:
 1831                 db_printf("TCPS_CLOSING");
 1832                 return;
 1833 
 1834         case TCPS_LAST_ACK:
 1835                 db_printf("TCPS_LAST_ACK");
 1836                 return;
 1837 
 1838         case TCPS_FIN_WAIT_2:
 1839                 db_printf("TCPS_FIN_WAIT_2");
 1840                 return;
 1841 
 1842         case TCPS_TIME_WAIT:
 1843                 db_printf("TCPS_TIME_WAIT");
 1844                 return;
 1845 
 1846         default:
 1847                 db_printf("unknown");
 1848                 return;
 1849         }
 1850 }
 1851 
 1852 static void
 1853 db_print_tflags(u_int t_flags)
 1854 {
 1855         int comma;
 1856 
 1857         comma = 0;
 1858         if (t_flags & TF_ACKNOW) {
 1859                 db_printf("%sTF_ACKNOW", comma ? ", " : "");
 1860                 comma = 1;
 1861         }
 1862         if (t_flags & TF_DELACK) {
 1863                 db_printf("%sTF_DELACK", comma ? ", " : "");
 1864                 comma = 1;
 1865         }
 1866         if (t_flags & TF_NODELAY) {
 1867                 db_printf("%sTF_NODELAY", comma ? ", " : "");
 1868                 comma = 1;
 1869         }
 1870         if (t_flags & TF_NOOPT) {
 1871                 db_printf("%sTF_NOOPT", comma ? ", " : "");
 1872                 comma = 1;
 1873         }
 1874         if (t_flags & TF_SENTFIN) {
 1875                 db_printf("%sTF_SENTFIN", comma ? ", " : "");
 1876                 comma = 1;
 1877         }
 1878         if (t_flags & TF_REQ_SCALE) {
 1879                 db_printf("%sTF_REQ_SCALE", comma ? ", " : "");
 1880                 comma = 1;
 1881         }
 1882         if (t_flags & TF_RCVD_SCALE) {
 1883                 db_printf("%sTF_RECVD_SCALE", comma ? ", " : "");
 1884                 comma = 1;
 1885         }
 1886         if (t_flags & TF_REQ_TSTMP) {
 1887                 db_printf("%sTF_REQ_TSTMP", comma ? ", " : "");
 1888                 comma = 1;
 1889         }
 1890         if (t_flags & TF_RCVD_TSTMP) {
 1891                 db_printf("%sTF_RCVD_TSTMP", comma ? ", " : "");
 1892                 comma = 1;
 1893         }
 1894         if (t_flags & TF_SACK_PERMIT) {
 1895                 db_printf("%sTF_SACK_PERMIT", comma ? ", " : "");
 1896                 comma = 1;
 1897         }
 1898         if (t_flags & TF_NEEDSYN) {
 1899                 db_printf("%sTF_NEEDSYN", comma ? ", " : "");
 1900                 comma = 1;
 1901         }
 1902         if (t_flags & TF_NEEDFIN) {
 1903                 db_printf("%sTF_NEEDFIN", comma ? ", " : "");
 1904                 comma = 1;
 1905         }
 1906         if (t_flags & TF_NOPUSH) {
 1907                 db_printf("%sTF_NOPUSH", comma ? ", " : "");
 1908                 comma = 1;
 1909         }
 1910         if (t_flags & TF_MORETOCOME) {
 1911                 db_printf("%sTF_MORETOCOME", comma ? ", " : "");
 1912                 comma = 1;
 1913         }
 1914         if (t_flags & TF_LQ_OVERFLOW) {
 1915                 db_printf("%sTF_LQ_OVERFLOW", comma ? ", " : "");
 1916                 comma = 1;
 1917         }
 1918         if (t_flags & TF_LASTIDLE) {
 1919                 db_printf("%sTF_LASTIDLE", comma ? ", " : "");
 1920                 comma = 1;
 1921         }
 1922         if (t_flags & TF_RXWIN0SENT) {
 1923                 db_printf("%sTF_RXWIN0SENT", comma ? ", " : "");
 1924                 comma = 1;
 1925         }
 1926         if (t_flags & TF_FASTRECOVERY) {
 1927                 db_printf("%sTF_FASTRECOVERY", comma ? ", " : "");
 1928                 comma = 1;
 1929         }
 1930         if (t_flags & TF_CONGRECOVERY) {
 1931                 db_printf("%sTF_CONGRECOVERY", comma ? ", " : "");
 1932                 comma = 1;
 1933         }
 1934         if (t_flags & TF_WASFRECOVERY) {
 1935                 db_printf("%sTF_WASFRECOVERY", comma ? ", " : "");
 1936                 comma = 1;
 1937         }
 1938         if (t_flags & TF_SIGNATURE) {
 1939                 db_printf("%sTF_SIGNATURE", comma ? ", " : "");
 1940                 comma = 1;
 1941         }
 1942         if (t_flags & TF_FORCEDATA) {
 1943                 db_printf("%sTF_FORCEDATA", comma ? ", " : "");
 1944                 comma = 1;
 1945         }
 1946         if (t_flags & TF_TSO) {
 1947                 db_printf("%sTF_TSO", comma ? ", " : "");
 1948                 comma = 1;
 1949         }
 1950         if (t_flags & TF_ECN_PERMIT) {
 1951                 db_printf("%sTF_ECN_PERMIT", comma ? ", " : "");
 1952                 comma = 1;
 1953         }
 1954 }
 1955 
 1956 static void
 1957 db_print_toobflags(char t_oobflags)
 1958 {
 1959         int comma;
 1960 
 1961         comma = 0;
 1962         if (t_oobflags & TCPOOB_HAVEDATA) {
 1963                 db_printf("%sTCPOOB_HAVEDATA", comma ? ", " : "");
 1964                 comma = 1;
 1965         }
 1966         if (t_oobflags & TCPOOB_HADDATA) {
 1967                 db_printf("%sTCPOOB_HADDATA", comma ? ", " : "");
 1968                 comma = 1;
 1969         }
 1970 }
 1971 
 1972 static void
 1973 db_print_tcpcb(struct tcpcb *tp, const char *name, int indent)
 1974 {
 1975 
 1976         db_print_indent(indent);
 1977         db_printf("%s at %p\n", name, tp);
 1978 
 1979         indent += 2;
 1980 
 1981         db_print_indent(indent);
 1982         db_printf("t_segq first: %p   t_segqlen: %d   t_dupacks: %d\n",
 1983            LIST_FIRST(&tp->t_segq), tp->t_segqlen, tp->t_dupacks);
 1984 
 1985         db_print_indent(indent);
 1986         db_printf("tt_rexmt: %p   tt_persist: %p   tt_keep: %p\n",
 1987             &tp->t_timers->tt_rexmt, &tp->t_timers->tt_persist, &tp->t_timers->tt_keep);
 1988 
 1989         db_print_indent(indent);
 1990         db_printf("tt_2msl: %p   tt_delack: %p   t_inpcb: %p\n", &tp->t_timers->tt_2msl,
 1991             &tp->t_timers->tt_delack, tp->t_inpcb);
 1992 
 1993         db_print_indent(indent);
 1994         db_printf("t_state: %d (", tp->t_state);
 1995         db_print_tstate(tp->t_state);
 1996         db_printf(")\n");
 1997 
 1998         db_print_indent(indent);
 1999         db_printf("t_flags: 0x%x (", tp->t_flags);
 2000         db_print_tflags(tp->t_flags);
 2001         db_printf(")\n");
 2002 
 2003         db_print_indent(indent);
 2004         db_printf("snd_una: 0x%08x   snd_max: 0x%08x   snd_nxt: x0%08x\n",
 2005             tp->snd_una, tp->snd_max, tp->snd_nxt);
 2006 
 2007         db_print_indent(indent);
 2008         db_printf("snd_up: 0x%08x   snd_wl1: 0x%08x   snd_wl2: 0x%08x\n",
 2009            tp->snd_up, tp->snd_wl1, tp->snd_wl2);
 2010 
 2011         db_print_indent(indent);
 2012         db_printf("iss: 0x%08x   irs: 0x%08x   rcv_nxt: 0x%08x\n",
 2013             tp->iss, tp->irs, tp->rcv_nxt);
 2014 
 2015         db_print_indent(indent);
 2016         db_printf("rcv_adv: 0x%08x   rcv_wnd: %lu   rcv_up: 0x%08x\n",
 2017             tp->rcv_adv, tp->rcv_wnd, tp->rcv_up);
 2018 
 2019         db_print_indent(indent);
 2020         db_printf("snd_wnd: %lu   snd_cwnd: %lu\n",
 2021            tp->snd_wnd, tp->snd_cwnd);
 2022 
 2023         db_print_indent(indent);
 2024         db_printf("snd_ssthresh: %lu   snd_recover: "
 2025             "0x%08x\n", tp->snd_ssthresh, tp->snd_recover);
 2026 
 2027         db_print_indent(indent);
 2028         db_printf("t_maxopd: %u   t_rcvtime: %u   t_startime: %u\n",
 2029             tp->t_maxopd, tp->t_rcvtime, tp->t_starttime);
 2030 
 2031         db_print_indent(indent);
 2032         db_printf("t_rttime: %u   t_rtsq: 0x%08x\n",
 2033             tp->t_rtttime, tp->t_rtseq);
 2034 
 2035         db_print_indent(indent);
 2036         db_printf("t_rxtcur: %d   t_maxseg: %u   t_srtt: %d\n",
 2037             tp->t_rxtcur, tp->t_maxseg, tp->t_srtt);
 2038 
 2039         db_print_indent(indent);
 2040         db_printf("t_rttvar: %d   t_rxtshift: %d   t_rttmin: %u   "
 2041             "t_rttbest: %u\n", tp->t_rttvar, tp->t_rxtshift, tp->t_rttmin,
 2042             tp->t_rttbest);
 2043 
 2044         db_print_indent(indent);
 2045         db_printf("t_rttupdated: %lu   max_sndwnd: %lu   t_softerror: %d\n",
 2046             tp->t_rttupdated, tp->max_sndwnd, tp->t_softerror);
 2047 
 2048         db_print_indent(indent);
 2049         db_printf("t_oobflags: 0x%x (", tp->t_oobflags);
 2050         db_print_toobflags(tp->t_oobflags);
 2051         db_printf(")   t_iobc: 0x%02x\n", tp->t_iobc);
 2052 
 2053         db_print_indent(indent);
 2054         db_printf("snd_scale: %u   rcv_scale: %u   request_r_scale: %u\n",
 2055             tp->snd_scale, tp->rcv_scale, tp->request_r_scale);
 2056 
 2057         db_print_indent(indent);
 2058         db_printf("ts_recent: %u   ts_recent_age: %u\n",
 2059             tp->ts_recent, tp->ts_recent_age);
 2060 
 2061         db_print_indent(indent);
 2062         db_printf("ts_offset: %u   last_ack_sent: 0x%08x   snd_cwnd_prev: "
 2063             "%lu\n", tp->ts_offset, tp->last_ack_sent, tp->snd_cwnd_prev);
 2064 
 2065         db_print_indent(indent);
 2066         db_printf("snd_ssthresh_prev: %lu   snd_recover_prev: 0x%08x   "
 2067             "t_badrxtwin: %u\n", tp->snd_ssthresh_prev,
 2068             tp->snd_recover_prev, tp->t_badrxtwin);
 2069 
 2070         db_print_indent(indent);
 2071         db_printf("snd_numholes: %d  snd_holes first: %p\n",
 2072             tp->snd_numholes, TAILQ_FIRST(&tp->snd_holes));
 2073 
 2074         db_print_indent(indent);
 2075         db_printf("snd_fack: 0x%08x   rcv_numsacks: %d   sack_newdata: "
 2076             "0x%08x\n", tp->snd_fack, tp->rcv_numsacks, tp->sack_newdata);
 2077 
 2078         /* Skip sackblks, sackhint. */
 2079 
 2080         db_print_indent(indent);
 2081         db_printf("t_rttlow: %d   rfbuf_ts: %u   rfbuf_cnt: %d\n",
 2082             tp->t_rttlow, tp->rfbuf_ts, tp->rfbuf_cnt);
 2083 }
 2084 
 2085 DB_SHOW_COMMAND(tcpcb, db_show_tcpcb)
 2086 {
 2087         struct tcpcb *tp;
 2088 
 2089         if (!have_addr) {
 2090                 db_printf("usage: show tcpcb <addr>\n");
 2091                 return;
 2092         }
 2093         tp = (struct tcpcb *)addr;
 2094 
 2095         db_print_tcpcb(tp, "tcpcb", 0);
 2096 }
 2097 #endif

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