sys/netinet/tcp_usrreq.c

   1 /*
   2  * Copyright (c) 2003, 2004 Jeffrey M. Hsu.  All rights reserved.
   3  * Copyright (c) 2003, 2004 The DragonFly Project.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to The DragonFly Project
   6  * by Jeffrey M. Hsu.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of The DragonFly Project nor the names of its
  17  *    contributors may be used to endorse or promote products derived
  18  *    from this software without specific, prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  23  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  24  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  25  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  27  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  30  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 /*
  35  * Copyright (c) 1982, 1986, 1988, 1993
  36  *      The Regents of the University of California.  All rights reserved.
  37  *
  38  * Redistribution and use in source and binary forms, with or without
  39  * modification, are permitted provided that the following conditions
  40  * are met:
  41  * 1. Redistributions of source code must retain the above copyright
  42  *    notice, this list of conditions and the following disclaimer.
  43  * 2. Redistributions in binary form must reproduce the above copyright
  44  *    notice, this list of conditions and the following disclaimer in the
  45  *    documentation and/or other materials provided with the distribution.
  46  * 3. Neither the name of the University nor the names of its contributors
  47  *    may be used to endorse or promote products derived from this software
  48  *    without specific prior written permission.
  49  *
  50  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  51  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  52  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  53  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  54  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  55  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  56  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  57  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  58  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  59  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  60  * SUCH DAMAGE.
  61  *
  62  *      From: @(#)tcp_usrreq.c  8.2 (Berkeley) 1/3/94
  63  * $FreeBSD: src/sys/netinet/tcp_usrreq.c,v 1.51.2.17 2002/10/11 11:46:44 ume Exp $
  64  */
  65
  66 #include "opt_ipsec.h"
  67 #include "opt_inet.h"
  68 #include "opt_inet6.h"
  69 #include "opt_tcpdebug.h"
  70
  71 #include <sys/param.h>
  72 #include <sys/systm.h>
  73 #include <sys/kernel.h>
  74 #include <sys/malloc.h>
  75 #include <sys/sysctl.h>
  76 #include <sys/globaldata.h>
  77 #include <sys/thread.h>
  78
  79 #include <sys/mbuf.h>
  80 #ifdef INET6
  81 #include <sys/domain.h>
  82 #endif /* INET6 */
  83 #include <sys/socket.h>
  84 #include <sys/socketvar.h>
  85 #include <sys/socketops.h>
  86 #include <sys/protosw.h>
  87
  88 #include <sys/thread2.h>
  89 #include <sys/msgport2.h>
  90 #include <sys/socketvar2.h>
  91
  92 #include <net/if.h>
  93 #include <net/netisr.h>
  94 #include <net/route.h>
  95
  96 #include <net/netmsg2.h>
  97 #include <net/netisr2.h>
  98
  99 #include <netinet/in.h>
 100 #include <netinet/in_systm.h>
 101 #ifdef INET6
 102 #include <netinet/ip6.h>
 103 #endif
 104 #include <netinet/in_pcb.h>
 105 #ifdef INET6
 106 #include <netinet6/in6_pcb.h>
 107 #endif
 108 #include <netinet/in_var.h>
 109 #include <netinet/ip_var.h>
 110 #ifdef INET6
 111 #include <netinet6/ip6_var.h>
 112 #include <netinet6/tcp6_var.h>
 113 #endif
 114 #include <netinet/tcp.h>
 115 #include <netinet/tcp_fsm.h>
 116 #include <netinet/tcp_seq.h>
 117 #include <netinet/tcp_timer.h>
 118 #include <netinet/tcp_timer2.h>
 119 #include <netinet/tcp_var.h>
 120 #include <netinet/tcpip.h>
 121 #ifdef TCPDEBUG
 122 #include <netinet/tcp_debug.h>
 123 #endif
 124
 125 #ifdef IPSEC
 126 #include <netinet6/ipsec.h>
 127 #endif /*IPSEC*/
 128
 129 /*
 130  * TCP protocol interface to socket abstraction.
 131  */
 132 extern  char *tcpstates[];      /* XXX ??? */
 133
 134 static int      tcp_attach (struct socket *, struct pru_attach_info *);
 135 static void     tcp_connect (netmsg_t msg);
 136 #ifdef INET6
 137 static void     tcp6_connect (netmsg_t msg);
 138 static int      tcp6_connect_oncpu(struct tcpcb *tp, int flags,
 139                                 struct mbuf **mp,
 140                                 struct sockaddr_in6 *sin6,
 141                                 struct in6_addr *addr6);
 142 #endif /* INET6 */
 143 static struct tcpcb *
 144                 tcp_disconnect (struct tcpcb *);
 145 static struct tcpcb *
 146                 tcp_usrclosed (struct tcpcb *);
 147
 148 #ifdef TCPDEBUG
 149 #define TCPDEBUG0       int ostate = 0
 150 #define TCPDEBUG1()     ostate = tp ? tp->t_state : 0
 151 #define TCPDEBUG2(req)  if (tp && (so->so_options & SO_DEBUG)) \
 152                                 tcp_trace(TA_USER, ostate, tp, 0, 0, req)
 153 #else
 154 #define TCPDEBUG0
 155 #define TCPDEBUG1()
 156 #define TCPDEBUG2(req)
 157 #endif
 158
 159 /*
 160  * For some ill optimized programs, which try to use TCP_NOPUSH
 161  * to improve performance, will have small amount of data sits
 162  * in the sending buffer.  These small amount of data will _not_
 163  * be pushed into the network until more data are written into
 164  * the socket or the socket write side is shutdown.
 165  */
 166 static int      tcp_disable_nopush = 1;
 167 SYSCTL_INT(_net_inet_tcp, OID_AUTO, disable_nopush, CTLFLAG_RW,
 168     &tcp_disable_nopush, 0, "TCP_NOPUSH socket option will have no effect");
 169
 170 /*
 171  * Allocate socket buffer space.
 172  */
 173 static int
 174 tcp_usr_preattach(struct socket *so, int proto __unused,
 175     struct pru_attach_info *ai)
 176 {
 177         int error;
 178
 179         if (so->so_snd.ssb_hiwat == 0 || so->so_rcv.ssb_hiwat == 0) {
 180                 error = soreserve(so, tcp_sendspace, tcp_recvspace,
 181                                   ai->sb_rlimit);
 182                 if (error)
 183                         return (error);
 184         }
 185         atomic_set_int(&so->so_rcv.ssb_flags, SSB_AUTOSIZE);
 186         atomic_set_int(&so->so_snd.ssb_flags, SSB_AUTOSIZE | SSB_PREALLOC);
 187
 188         return 0;
 189 }
 190
 191 /*
 192  * TCP attaches to socket via pru_attach(), reserving space,
 193  * and an internet control block.  This socket may move to
 194  * other CPU later when we bind/connect.
 195  */
 196 static void
 197 tcp_usr_attach(netmsg_t msg)
 198 {
 199         struct socket *so = msg->base.nm_so;
 200         struct pru_attach_info *ai = msg->attach.nm_ai;
 201         int error;
 202         struct inpcb *inp;
 203         struct tcpcb *tp = NULL;
 204         TCPDEBUG0;
 205
 206         inp = so->so_pcb;
 207         KASSERT(inp == NULL, ("tcp socket attached"));
 208         TCPDEBUG1();
 209
 210         error = tcp_attach(so, ai);
 211         if (error)
 212                 goto out;
 213
 214         if ((so->so_options & SO_LINGER) && so->so_linger == 0)
 215                 so->so_linger = TCP_LINGERTIME;
 216         tp = sototcpcb(so);
 217 out:
 218         TCPDEBUG2(PRU_ATTACH);
 219         lwkt_replymsg(&msg->lmsg, error);
 220 }
 221
 222 /*
 223  * pru_detach() detaches the TCP protocol from the socket.
 224  * If the protocol state is non-embryonic, then can't
 225  * do this directly: have to initiate a pru_disconnect(),
 226  * which may finish later; embryonic TCB's can just
 227  * be discarded here.
 228  */
 229 static void
 230 tcp_usr_detach(netmsg_t msg)
 231 {
 232         struct socket *so = msg->base.nm_so;
 233         int error = 0;
 234         struct inpcb *inp;
 235         struct tcpcb *tp;
 236         TCPDEBUG0;
 237
 238         inp = so->so_pcb;
 239
 240         /*
 241          * If the inp is already detached or never attached, it may have
 242          * been due to an async close or async attach failure.  Just return
 243          * as if no error occured.
 244          */
 245         if (inp) {
 246                 tp = intotcpcb(inp);
 247                 KASSERT(tp != NULL, ("tcp_usr_detach: tp is NULL"));
 248                 TCPDEBUG1();
 249                 tp = tcp_disconnect(tp);
 250                 TCPDEBUG2(PRU_DETACH);
 251         }
 252         lwkt_replymsg(&msg->lmsg, error);
 253 }
 254
 255 /*
 256  * NOTE: ignore_error is non-zero for certain disconnection races
 257  * which we want to silently allow, otherwise close() may return
 258  * an unexpected error.
 259  *
 260  * NOTE: The variables (msg) and (tp) are assumed.
 261  */
 262 #define COMMON_START(so, inp, ignore_error)                     \
 263         TCPDEBUG0;                                              \
 264                                                                 \
 265         inp = so->so_pcb;                                       \
 266         do {                                                    \
 267                 if (inp == NULL) {                              \
 268                         error = ignore_error ? 0 : EINVAL;      \
 269                         tp = NULL;                              \
 270                         goto out;                               \
 271                 }                                               \
 272                 tp = intotcpcb(inp);                            \
 273                 TCPDEBUG1();                                    \
 274         } while(0)
 275
 276 #define COMMON_END1(req, noreply)                               \
 277         out: do {                                               \
 278                 TCPDEBUG2(req);                                 \
 279                 if (!(noreply))                                 \
 280                         lwkt_replymsg(&msg->lmsg, error);       \
 281                 return;                                         \
 282         } while(0)
 283
 284 #define COMMON_END(req)         COMMON_END1((req), 0)
 285
 286 static void
 287 tcp_sosetport(struct lwkt_msg *msg, lwkt_port_t port)
 288 {
 289         sosetport(((struct netmsg_base *)msg)->nm_so, port);
 290 }
 291
 292 /*
 293  * Give the socket an address.
 294  */
 295 static void
 296 tcp_usr_bind(netmsg_t msg)
 297 {
 298         struct socket *so = msg->bind.base.nm_so;
 299         struct sockaddr *nam = msg->bind.nm_nam;
 300         struct thread *td = msg->bind.nm_td;
 301         int error = 0;
 302         struct inpcb *inp;
 303         struct tcpcb *tp;
 304         struct sockaddr_in *sinp;
 305         lwkt_port_t port0 = netisr_cpuport(0);
 306
 307         COMMON_START(so, inp, 0);
 308
 309         /*
 310          * Must check for multicast addresses and disallow binding
 311          * to them.
 312          */
 313         sinp = (struct sockaddr_in *)nam;
 314         if (sinp->sin_family == AF_INET &&
 315             IN_MULTICAST(ntohl(sinp->sin_addr.s_addr))) {
 316                 error = EAFNOSUPPORT;
 317                 goto out;
 318         }
 319
 320         /*
 321          * Check "already bound" here (in_pcbbind() does the same check
 322          * though), so we don't forward a connected socket to netisr0,
 323          * which would panic in the following in_pcbunlink().
 324          */
 325         if (inp->inp_lport != 0 || inp->inp_laddr.s_addr != INADDR_ANY) {
 326                 error = EINVAL; /* already bound */
 327                 goto out;
 328         }
 329
 330         /*
 331          * Use netisr0 to serialize in_pcbbind(), so that pru_detach and
 332          * pru_bind for different sockets on the same local port could be
 333          * properly ordered.  The original race is illustrated here for
 334          * reference.
 335          *
 336          * s1 = socket();
 337          * bind(s1, *.PORT);
 338          * close(s1);  <----- asynchronous
 339          * s2 = socket();
 340          * bind(s2, *.PORT);
 341          *
 342          * All will expect bind(s2, *.PORT) to succeed.  However, it will
 343          * fail, if following sequence happens due to random socket initial
 344          * msgport and asynchronous close(2):
 345          *
 346          *    netisrN                  netisrM
 347          *       :                        :
 348          *       :                    pru_bind(s2) [*.PORT is used by s1]
 349          *  pru_detach(s1)                :
 350          */
 351         if (&curthread->td_msgport != port0) {
 352                 lwkt_msg_t lmsg = &msg->bind.base.lmsg;
 353
 354                 KASSERT((msg->bind.nm_flags & PRUB_RELINK) == 0,
 355                     ("already asked to relink"));
 356
 357                 in_pcbunlink(so->so_pcb, &tcbinfo[mycpuid]);
 358                 msg->bind.nm_flags |= PRUB_RELINK;
 359
 360                 TCP_STATE_MIGRATE_START(tp);
 361
 362                 /* See the related comment in tcp_connect() */
 363                 lwkt_setmsg_receipt(lmsg, tcp_sosetport);
 364                 lwkt_forwardmsg(port0, lmsg);
 365                 /* msg invalid now */
 366                 return;
 367         }
 368         KASSERT(so->so_port == port0, ("so_port is not netisr0"));
 369
 370         if (msg->bind.nm_flags & PRUB_RELINK) {
 371                 msg->bind.nm_flags &= ~PRUB_RELINK;
 372                 TCP_STATE_MIGRATE_END(tp);
 373                 in_pcblink(so->so_pcb, &tcbinfo[mycpuid]);
 374         }
 375         KASSERT(inp->inp_pcbinfo == &tcbinfo[0], ("pcbinfo is not tcbinfo0"));
 376
 377         error = in_pcbbind(inp, nam, td);
 378         if (error)
 379                 goto out;
 380
 381         COMMON_END(PRU_BIND);
 382 }
 383
 384 #ifdef INET6
 385
 386 static void
 387 tcp6_usr_bind(netmsg_t msg)
 388 {
 389         struct socket *so = msg->bind.base.nm_so;
 390         struct sockaddr *nam = msg->bind.nm_nam;
 391         struct thread *td = msg->bind.nm_td;
 392         int error = 0;
 393         struct inpcb *inp;
 394         struct tcpcb *tp;
 395         struct sockaddr_in6 *sin6p;
 396
 397         COMMON_START(so, inp, 0);
 398
 399         /*
 400          * Must check for multicast addresses and disallow binding
 401          * to them.
 402          */
 403         sin6p = (struct sockaddr_in6 *)nam;
 404         if (sin6p->sin6_family == AF_INET6 &&
 405             IN6_IS_ADDR_MULTICAST(&sin6p->sin6_addr)) {
 406                 error = EAFNOSUPPORT;
 407                 goto out;
 408         }
 409         error = in6_pcbbind(inp, nam, td);
 410         if (error)
 411                 goto out;
 412         COMMON_END(PRU_BIND);
 413 }
 414 #endif /* INET6 */
 415
 416 struct netmsg_inswildcard {
 417         struct netmsg_base      base;
 418         struct inpcb            *nm_inp;
 419 };
 420
 421 static void
 422 in_pcbinswildcardhash_handler(netmsg_t msg)
 423 {
 424         struct netmsg_inswildcard *nm = (struct netmsg_inswildcard *)msg;
 425         int cpu = mycpuid, nextcpu;
 426
 427         in_pcbinswildcardhash_oncpu(nm->nm_inp, &tcbinfo[cpu]);
 428
 429         nextcpu = cpu + 1;
 430         if (nextcpu < netisr_ncpus)
 431                 lwkt_forwardmsg(netisr_cpuport(nextcpu), &nm->base.lmsg);
 432         else
 433                 lwkt_replymsg(&nm->base.lmsg, 0);
 434 }
 435
 436 /*
 437  * Prepare to accept connections.
 438  */
 439 static void
 440 tcp_usr_listen(netmsg_t msg)
 441 {
 442         struct socket *so = msg->listen.base.nm_so;
 443         struct thread *td = msg->listen.nm_td;
 444         int error = 0;
 445         struct inpcb *inp;
 446         struct tcpcb *tp;
 447         struct netmsg_inswildcard nm;
 448         lwkt_port_t port0 = netisr_cpuport(0);
 449
 450         COMMON_START(so, inp, 0);
 451
 452         if (&curthread->td_msgport != port0) {
 453                 lwkt_msg_t lmsg = &msg->listen.base.lmsg;
 454
 455                 KASSERT((msg->listen.nm_flags & PRUL_RELINK) == 0,
 456                     ("already asked to relink"));
 457
 458                 in_pcbunlink(so->so_pcb, &tcbinfo[mycpuid]);
 459                 msg->listen.nm_flags |= PRUL_RELINK;
 460
 461                 TCP_STATE_MIGRATE_START(tp);
 462
 463                 /* See the related comment in tcp_connect() */
 464                 lwkt_setmsg_receipt(lmsg, tcp_sosetport);
 465                 lwkt_forwardmsg(port0, lmsg);
 466                 /* msg invalid now */
 467                 return;
 468         }
 469         KASSERT(so->so_port == port0, ("so_port is not netisr0"));
 470
 471         if (msg->listen.nm_flags & PRUL_RELINK) {
 472                 msg->listen.nm_flags &= ~PRUL_RELINK;
 473                 TCP_STATE_MIGRATE_END(tp);
 474                 in_pcblink(so->so_pcb, &tcbinfo[mycpuid]);
 475         }
 476         KASSERT(inp->inp_pcbinfo == &tcbinfo[0], ("pcbinfo is not tcbinfo0"));
 477
 478         if (tp->t_flags & TF_LISTEN)
 479                 goto out;
 480
 481         if (inp->inp_lport == 0) {
 482                 error = in_pcbbind(inp, NULL, td);
 483                 if (error)
 484                         goto out;
 485         }
 486
 487         TCP_STATE_CHANGE(tp, TCPS_LISTEN);
 488         tp->t_flags |= TF_LISTEN;
 489         tp->tt_msg = NULL; /* Catch any invalid timer usage */
 490
 491         /*
 492          * Create tcpcb per-cpu port cache
 493          *
 494          * NOTE:
 495          * This _must_ be done before installing this inpcb into
 496          * wildcard hash.
 497          */
 498         tcp_pcbport_create(tp);
 499
 500         if (netisr_ncpus > 1) {
 501                 /*
 502                  * Put this inpcb into wildcard hash on other cpus.
 503                  */
 504                 ASSERT_INP_NOTINHASH(inp);
 505                 netmsg_init(&nm.base, NULL, &curthread->td_msgport,
 506                             MSGF_PRIORITY, in_pcbinswildcardhash_handler);
 507                 nm.nm_inp = inp;
 508                 lwkt_domsg(netisr_cpuport(1), &nm.base.lmsg, 0);
 509         }
 510         in_pcbinswildcardhash(inp);
 511         COMMON_END(PRU_LISTEN);
 512 }
 513
 514 #ifdef INET6
 515
 516 static void
 517 tcp6_usr_listen(netmsg_t msg)
 518 {
 519         struct socket *so = msg->listen.base.nm_so;
 520         struct thread *td = msg->listen.nm_td;
 521         int error = 0;
 522         struct inpcb *inp;
 523         struct tcpcb *tp;
 524         struct netmsg_inswildcard nm;
 525
 526         COMMON_START(so, inp, 0);
 527
 528         if (tp->t_flags & TF_LISTEN)
 529                 goto out;
 530
 531         if (inp->inp_lport == 0) {
 532                 error = in6_pcbbind(inp, NULL, td);
 533                 if (error)
 534                         goto out;
 535         }
 536
 537         TCP_STATE_CHANGE(tp, TCPS_LISTEN);
 538         tp->t_flags |= TF_LISTEN;
 539         tp->tt_msg = NULL; /* Catch any invalid timer usage */
 540
 541         /*
 542          * Create tcpcb per-cpu port cache
 543          *
 544          * NOTE:
 545          * This _must_ be done before installing this inpcb into
 546          * wildcard hash.
 547          */
 548         tcp_pcbport_create(tp);
 549
 550         if (netisr_ncpus > 1) {
 551                 /*
 552                  * Put this inpcb into wildcard hash on other cpus.
 553                  */
 554                 KKASSERT(so->so_port == netisr_cpuport(0));
 555                 ASSERT_NETISR0;
 556                 KKASSERT(inp->inp_pcbinfo == &tcbinfo[0]);
 557                 ASSERT_INP_NOTINHASH(inp);
 558
 559                 netmsg_init(&nm.base, NULL, &curthread->td_msgport,
 560                             MSGF_PRIORITY, in_pcbinswildcardhash_handler);
 561                 nm.nm_inp = inp;
 562                 lwkt_domsg(netisr_cpuport(1), &nm.base.lmsg, 0);
 563         }
 564         in_pcbinswildcardhash(inp);
 565         COMMON_END(PRU_LISTEN);
 566 }
 567 #endif /* INET6 */
 568
 569 /*
 570  * Initiate connection to peer.
 571  * Create a template for use in transmissions on this connection.
 572  * Enter SYN_SENT state, and mark socket as connecting.
 573  * Start keep-alive timer, and seed output sequence space.
 574  * Send initial segment on connection.
 575  */
 576 static void
 577 tcp_usr_connect(netmsg_t msg)
 578 {
 579         struct socket *so = msg->connect.base.nm_so;
 580         struct sockaddr *nam = msg->connect.nm_nam;
 581         struct thread *td = msg->connect.nm_td;
 582         int error = 0;
 583         struct inpcb *inp;
 584         struct tcpcb *tp;
 585         struct sockaddr_in *sinp;
 586
 587         ASSERT_NETISR_NCPUS(mycpuid);
 588
 589         COMMON_START(so, inp, 0);
 590
 591         /*
 592          * Must disallow TCP ``connections'' to multicast addresses.
 593          */
 594         sinp = (struct sockaddr_in *)nam;
 595         if (sinp->sin_family == AF_INET
 596             && IN_MULTICAST(ntohl(sinp->sin_addr.s_addr))) {
 597                 error = EAFNOSUPPORT;
 598                 goto out;
 599         }
 600
 601         if (!prison_remote_ip(td, (struct sockaddr*)sinp)) {
 602                 error = EAFNOSUPPORT; /* IPv6 only jail */
 603                 goto out;
 604         }
 605
 606         tcp_connect(msg);
 607         /* msg is invalid now */
 608         return;
 609 out:
 610         if (msg->connect.nm_m) {
 611                 m_freem(msg->connect.nm_m);
 612                 msg->connect.nm_m = NULL;
 613         }
 614         if (msg->connect.nm_flags & PRUC_HELDTD)
 615                 lwkt_rele(td);
 616         if (error && (msg->connect.nm_flags & PRUC_ASYNC)) {
 617                 so->so_error = error;
 618                 soisdisconnected(so);
 619         }
 620         lwkt_replymsg(&msg->lmsg, error);
 621 }
 622
 623 #ifdef INET6
 624
 625 static void
 626 tcp6_usr_connect(netmsg_t msg)
 627 {
 628         struct socket *so = msg->connect.base.nm_so;
 629         struct sockaddr *nam = msg->connect.nm_nam;
 630         struct thread *td = msg->connect.nm_td;
 631         int error = 0;
 632         struct inpcb *inp;
 633         struct tcpcb *tp;
 634         struct sockaddr_in6 *sin6p;
 635
 636         ASSERT_NETISR_NCPUS(mycpuid);
 637
 638         COMMON_START(so, inp, 0);
 639
 640         /*
 641          * Must disallow TCP ``connections'' to multicast addresses.
 642          */
 643         sin6p = (struct sockaddr_in6 *)nam;
 644         if (sin6p->sin6_family == AF_INET6
 645             && IN6_IS_ADDR_MULTICAST(&sin6p->sin6_addr)) {
 646                 error = EAFNOSUPPORT;
 647                 goto out;
 648         }
 649
 650         if (!prison_remote_ip(td, nam)) {
 651                 error = EAFNOSUPPORT; /* IPv4 only jail */
 652                 goto out;
 653         }
 654
 655         /* Reject v4-mapped address */
 656         if (IN6_IS_ADDR_V4MAPPED(&sin6p->sin6_addr)) {
 657                 error = EADDRNOTAVAIL;
 658                 goto out;
 659         }
 660
 661         inp->inp_inc.inc_isipv6 = 1;
 662         tcp6_connect(msg);
 663         /* msg is invalid now */
 664         return;
 665 out:
 666         if (msg->connect.nm_m) {
 667                 m_freem(msg->connect.nm_m);
 668                 msg->connect.nm_m = NULL;
 669         }
 670         lwkt_replymsg(&msg->lmsg, error);
 671 }
 672
 673 #endif /* INET6 */
 674
 675 /*
 676  * Initiate disconnect from peer.
 677  * If connection never passed embryonic stage, just drop;
 678  * else if don't need to let data drain, then can just drop anyways,
 679  * else have to begin TCP shutdown process: mark socket disconnecting,
 680  * drain unread data, state switch to reflect user close, and
 681  * send segment (e.g. FIN) to peer.  Socket will be really disconnected
 682  * when peer sends FIN and acks ours.
 683  *
 684  * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
 685  */
 686 static void
 687 tcp_usr_disconnect(netmsg_t msg)
 688 {
 689         struct socket *so = msg->disconnect.base.nm_so;
 690         int error = 0;
 691         struct inpcb *inp;
 692         struct tcpcb *tp;
 693
 694         COMMON_START(so, inp, 1);
 695         tp = tcp_disconnect(tp);
 696         COMMON_END(PRU_DISCONNECT);
 697 }
 698
 699 /*
 700  * Accept a connection.  Essentially all the work is
 701  * done at higher levels; just return the address
 702  * of the peer, storing through addr.
 703  */
 704 static void
 705 tcp_usr_accept(netmsg_t msg)
 706 {
 707         struct socket *so = msg->accept.base.nm_so;
 708         struct sockaddr **nam = msg->accept.nm_nam;
 709         int error = 0;
 710         struct inpcb *inp;
 711         struct tcpcb *tp = NULL;
 712         TCPDEBUG0;
 713
 714         inp = so->so_pcb;
 715         if (so->so_state & SS_ISDISCONNECTED) {
 716                 error = ECONNABORTED;
 717                 goto out;
 718         }
 719         if (inp == NULL) {
 720                 error = EINVAL;
 721                 goto out;
 722         }
 723
 724         tp = intotcpcb(inp);
 725         TCPDEBUG1();
 726         in_setpeeraddr(so, nam);
 727         COMMON_END(PRU_ACCEPT);
 728 }
 729
 730 #ifdef INET6
 731 static void
 732 tcp6_usr_accept(netmsg_t msg)
 733 {
 734         struct socket *so = msg->accept.base.nm_so;
 735         struct sockaddr **nam = msg->accept.nm_nam;
 736         int error = 0;
 737         struct inpcb *inp;
 738         struct tcpcb *tp = NULL;
 739         TCPDEBUG0;
 740
 741         inp = so->so_pcb;
 742
 743         if (so->so_state & SS_ISDISCONNECTED) {
 744                 error = ECONNABORTED;
 745                 goto out;
 746         }
 747         if (inp == NULL) {
 748                 error = EINVAL;
 749                 goto out;
 750         }
 751         tp = intotcpcb(inp);
 752         TCPDEBUG1();
 753         in6_setpeeraddr(so, nam);
 754         COMMON_END(PRU_ACCEPT);
 755 }
 756 #endif /* INET6 */
 757
 758 /*
 759  * Mark the connection as being incapable of further output.
 760  */
 761 static void
 762 tcp_usr_shutdown(netmsg_t msg)
 763 {
 764         struct socket *so = msg->shutdown.base.nm_so;
 765         int error = 0;
 766         struct inpcb *inp;
 767         struct tcpcb *tp;
 768
 769         COMMON_START(so, inp, 0);
 770         socantsendmore(so);
 771         tp = tcp_usrclosed(tp);
 772         if (tp)
 773                 error = tcp_output(tp);
 774         COMMON_END(PRU_SHUTDOWN);
 775 }
 776
 777 /*
 778  * After a receive, possibly send window update to peer.
 779  */
 780 static void
 781 tcp_usr_rcvd(netmsg_t msg)
 782 {
 783         struct socket *so = msg->rcvd.base.nm_so;
 784         int error = 0, noreply = 0;
 785         struct inpcb *inp;
 786         struct tcpcb *tp;
 787
 788         COMMON_START(so, inp, 0);
 789
 790         if (msg->rcvd.nm_pru_flags & PRUR_ASYNC) {
 791                 noreply = 1;
 792                 so_async_rcvd_reply(so);
 793         }
 794         tcp_output(tp);
 795
 796         COMMON_END1(PRU_RCVD, noreply);
 797 }
 798
 799 /*
 800  * Do a send by putting data in output queue and updating urgent
 801  * marker if URG set.  Possibly send more data.  Unlike the other
 802  * pru_*() routines, the mbuf chains are our responsibility.  We
 803  * must either enqueue them or free them.  The other pru_* routines
 804  * generally are caller-frees.
 805  */
 806 static void
 807 tcp_usr_send(netmsg_t msg)
 808 {
 809         struct socket *so = msg->send.base.nm_so;
 810         int flags = msg->send.nm_flags;
 811         struct mbuf *m = msg->send.nm_m;
 812         int error = 0;
 813         struct inpcb *inp;
 814         struct tcpcb *tp;
 815         TCPDEBUG0;
 816
 817         KKASSERT(msg->send.nm_control == NULL);
 818         KKASSERT(msg->send.nm_addr == NULL);
 819         KKASSERT((flags & PRUS_FREEADDR) == 0);
 820
 821         inp = so->so_pcb;
 822
 823         if (inp == NULL) {
 824                 /*
 825                  * OOPS! we lost a race, the TCP session got reset after
 826                  * we checked SS_CANTSENDMORE, eg: while doing uiomove or a
 827                  * network interrupt in the non-critical section of sosend().
 828                  */
 829                 m_freem(m);
 830                 error = ECONNRESET;     /* XXX EPIPE? */
 831                 tp = NULL;
 832                 TCPDEBUG1();
 833                 goto out;
 834         }
 835         tp = intotcpcb(inp);
 836         TCPDEBUG1();
 837
 838 #ifdef foo
 839         /*
 840          * This is no longer necessary, since:
 841          * - sosendtcp() has already checked it for us
 842          * - It does not work with asynchronized send
 843          */
 844
 845         /*
 846          * Don't let too much OOB data build up
 847          */
 848         if (flags & PRUS_OOB) {
 849                 if (ssb_space(&so->so_snd) < -512) {
 850                         m_freem(m);
 851                         error = ENOBUFS;
 852                         goto out;
 853                 }
 854         }
 855 #endif
 856
 857         /*
 858          * Pump the data into the socket.
 859          */
 860         if (m) {
 861                 ssb_appendstream(&so->so_snd, m);
 862                 sowwakeup(so);
 863         }
 864         if (flags & PRUS_OOB) {
 865                 /*
 866                  * According to RFC961 (Assigned Protocols),
 867                  * the urgent pointer points to the last octet
 868                  * of urgent data.  We continue, however,
 869                  * to consider it to indicate the first octet
 870                  * of data past the urgent section.
 871                  * Otherwise, snd_up should be one lower.
 872                  */
 873                 tp->snd_up = tp->snd_una + so->so_snd.ssb_cc;
 874                 tp->t_flags |= TF_FORCE;
 875                 error = tcp_output(tp);
 876                 tp->t_flags &= ~TF_FORCE;
 877         } else {
 878                 if (flags & PRUS_EOF) {
 879                         /*
 880                          * Close the send side of the connection after
 881                          * the data is sent.
 882                          */
 883                         socantsendmore(so);
 884                         tp = tcp_usrclosed(tp);
 885                 }
 886                 if (tp != NULL && !tcp_output_pending(tp)) {
 887                         if (flags & PRUS_MORETOCOME)
 888                                 tp->t_flags |= TF_MORETOCOME;
 889                         error = tcp_output_fair(tp);
 890                         if (flags & PRUS_MORETOCOME)
 891                                 tp->t_flags &= ~TF_MORETOCOME;
 892                 }
 893         }
 894         COMMON_END1((flags & PRUS_OOB) ? PRU_SENDOOB :
 895                    ((flags & PRUS_EOF) ? PRU_SEND_EOF : PRU_SEND),
 896                    (flags & PRUS_NOREPLY));
 897 }
 898
 899 /*
 900  * NOTE: (so) is referenced from soabort*() and netmsg_pru_abort()
 901  *       will sofree() it when we return.
 902  */
 903 static void
 904 tcp_usr_abort(netmsg_t msg)
 905 {
 906         struct socket *so = msg->abort.base.nm_so;
 907         int error = 0;
 908         struct inpcb *inp;
 909         struct tcpcb *tp;
 910
 911         COMMON_START(so, inp, 1);
 912         tp = tcp_drop(tp, ECONNABORTED);
 913         COMMON_END(PRU_ABORT);
 914 }
 915
 916 /*
 917  * Receive out-of-band data.
 918  */
 919 static void
 920 tcp_usr_rcvoob(netmsg_t msg)
 921 {
 922         struct socket *so = msg->rcvoob.base.nm_so;
 923         struct mbuf *m = msg->rcvoob.nm_m;
 924         int flags = msg->rcvoob.nm_flags;
 925         int error = 0;
 926         struct inpcb *inp;
 927         struct tcpcb *tp;
 928
 929         COMMON_START(so, inp, 0);
 930         if ((so->so_oobmark == 0 &&
 931              (so->so_state & SS_RCVATMARK) == 0) ||
 932             so->so_options & SO_OOBINLINE ||
 933             tp->t_oobflags & TCPOOB_HADDATA) {
 934                 error = EINVAL;
 935                 goto out;
 936         }
 937         if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
 938                 error = EWOULDBLOCK;
 939                 goto out;
 940         }
 941         m->m_len = 1;
 942         *mtod(m, caddr_t) = tp->t_iobc;
 943         if ((flags & MSG_PEEK) == 0)
 944                 tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA);
 945         COMMON_END(PRU_RCVOOB);
 946 }
 947
 948 static void
 949 tcp_usr_savefaddr(struct socket *so, const struct sockaddr *faddr)
 950 {
 951         in_savefaddr(so, faddr);
 952 }
 953
 954 #ifdef INET6
 955 static void
 956 tcp6_usr_savefaddr(struct socket *so, const struct sockaddr *faddr)
 957 {
 958         in6_savefaddr(so, faddr);
 959 }
 960 #endif
 961
 962 static int
 963 tcp_usr_preconnect(struct socket *so, const struct sockaddr *nam,
 964     struct thread *td __unused)
 965 {
 966         const struct sockaddr_in *sinp;
 967
 968         sinp = (const struct sockaddr_in *)nam;
 969         if (sinp->sin_family == AF_INET &&
 970             IN_MULTICAST(ntohl(sinp->sin_addr.s_addr)))
 971                 return EAFNOSUPPORT;
 972
 973         soisconnecting(so);
 974         return 0;
 975 }
 976
 977 /* xxx - should be const */
 978 struct pr_usrreqs tcp_usrreqs = {
 979         .pru_abort = tcp_usr_abort,
 980         .pru_accept = tcp_usr_accept,
 981         .pru_attach = tcp_usr_attach,
 982         .pru_bind = tcp_usr_bind,
 983         .pru_connect = tcp_usr_connect,
 984         .pru_connect2 = pr_generic_notsupp,
 985         .pru_control = in_control_dispatch,
 986         .pru_detach = tcp_usr_detach,
 987         .pru_disconnect = tcp_usr_disconnect,
 988         .pru_listen = tcp_usr_listen,
 989         .pru_peeraddr = in_setpeeraddr_dispatch,
 990         .pru_rcvd = tcp_usr_rcvd,
 991         .pru_rcvoob = tcp_usr_rcvoob,
 992         .pru_send = tcp_usr_send,
 993         .pru_sense = pru_sense_null,
 994         .pru_shutdown = tcp_usr_shutdown,
 995         .pru_sockaddr = in_setsockaddr_dispatch,
 996         .pru_sosend = sosendtcp,
 997         .pru_soreceive = sorecvtcp,
 998         .pru_savefaddr = tcp_usr_savefaddr,
 999         .pru_preconnect = tcp_usr_preconnect,
1000         .pru_preattach = tcp_usr_preattach
1001 };
1002
1003 #ifdef INET6
1004 struct pr_usrreqs tcp6_usrreqs = {
1005         .pru_abort = tcp_usr_abort,
1006         .pru_accept = tcp6_usr_accept,
1007         .pru_attach = tcp_usr_attach,
1008         .pru_bind = tcp6_usr_bind,
1009         .pru_connect = tcp6_usr_connect,
1010         .pru_connect2 = pr_generic_notsupp,
1011         .pru_control = in6_control_dispatch,
1012         .pru_detach = tcp_usr_detach,
1013         .pru_disconnect = tcp_usr_disconnect,
1014         .pru_listen = tcp6_usr_listen,
1015         .pru_peeraddr = in6_setpeeraddr_dispatch,
1016         .pru_rcvd = tcp_usr_rcvd,
1017         .pru_rcvoob = tcp_usr_rcvoob,
1018         .pru_send = tcp_usr_send,
1019         .pru_sense = pru_sense_null,
1020         .pru_shutdown = tcp_usr_shutdown,
1021         .pru_sockaddr = in6_setsockaddr_dispatch,
1022         .pru_sosend = sosendtcp,
1023         .pru_soreceive = sorecvtcp,
1024         .pru_savefaddr = tcp6_usr_savefaddr
1025 };
1026 #endif /* INET6 */
1027
1028 static int
1029 tcp_connect_oncpu(struct tcpcb *tp, int flags, struct mbuf *m,
1030                   const struct sockaddr_in *sin, struct sockaddr_in *if_sin,
1031                   uint16_t hash)
1032 {
1033         struct inpcb *inp = tp->t_inpcb, *oinp;
1034         struct socket *so = inp->inp_socket;
1035         struct route *ro = &inp->inp_route;
1036
1037         KASSERT(inp->inp_pcbinfo == &tcbinfo[mycpu->gd_cpuid],
1038             ("pcbinfo mismatch"));
1039
1040         oinp = in_pcblookup_hash(inp->inp_pcbinfo,
1041                                  sin->sin_addr, sin->sin_port,
1042                                  (inp->inp_laddr.s_addr != INADDR_ANY ?
1043                                   inp->inp_laddr : if_sin->sin_addr),
1044                                 inp->inp_lport, 0, NULL);
1045         if (oinp != NULL) {
1046                 m_freem(m);
1047                 return (EADDRINUSE);
1048         }
1049         if (inp->inp_laddr.s_addr == INADDR_ANY)
1050                 inp->inp_laddr = if_sin->sin_addr;
1051         KASSERT(inp->inp_faddr.s_addr == sin->sin_addr.s_addr,
1052             ("faddr mismatch for reconnect"));
1053         KASSERT(inp->inp_fport == sin->sin_port,
1054             ("fport mismatch for reconnect"));
1055         in_pcbinsconnhash(inp);
1056
1057         inp->inp_flags |= INP_HASH;
1058         inp->inp_hashval = hash;
1059
1060         /*
1061          * We are now on the inpcb's owner CPU, if the cached route was
1062          * freed because the rtentry's owner CPU is not the current CPU
1063          * (e.g. in tcp_connect()), then we try to reallocate it here with
1064          * the hope that a rtentry may be cloned from a RTF_PRCLONING
1065          * rtentry.
1066          */
1067         if (!(inp->inp_socket->so_options & SO_DONTROUTE) && /*XXX*/
1068             ro->ro_rt == NULL) {
1069                 bzero(&ro->ro_dst, sizeof(struct sockaddr_in));
1070                 ro->ro_dst.sa_family = AF_INET;
1071                 ro->ro_dst.sa_len = sizeof(struct sockaddr_in);
1072                 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr =
1073                         sin->sin_addr;
1074                 rtalloc(ro);
1075         }
1076
1077         /*
1078          * Now that no more errors can occur, change the protocol processing
1079          * port to the current thread (which is the correct thread).
1080          *
1081          * Create TCP timer message now; we are on the tcpcb's owner
1082          * CPU/thread.
1083          */
1084         tcp_create_timermsg(tp, &curthread->td_msgport);
1085
1086         /*
1087          * Compute window scaling to request.  Use a larger scaling then
1088          * needed for the initial receive buffer in case the receive buffer
1089          * gets expanded.
1090          */
1091         if (tp->request_r_scale < TCP_MIN_WINSHIFT)
1092                 tp->request_r_scale = TCP_MIN_WINSHIFT;
1093         while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
1094                (TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.ssb_hiwat
1095         ) {
1096                 tp->request_r_scale++;
1097         }
1098
1099         soisconnecting(so);
1100         tcpstat.tcps_connattempt++;
1101         TCP_STATE_CHANGE(tp, TCPS_SYN_SENT);
1102         tcp_callout_reset(tp, tp->tt_keep, tp->t_keepinit, tcp_timer_keep);
1103         tp->iss = tcp_new_isn(tp);
1104         tcp_sendseqinit(tp);
1105         if (m) {
1106                 ssb_appendstream(&so->so_snd, m);
1107                 m = NULL;
1108                 if (flags & PRUS_OOB)
1109                         tp->snd_up = tp->snd_una + so->so_snd.ssb_cc;
1110         }
1111
1112         /*
1113          * Close the send side of the connection after
1114          * the data is sent if flagged.
1115          */
1116         if ((flags & (PRUS_OOB|PRUS_EOF)) == PRUS_EOF) {
1117                 socantsendmore(so);
1118                 tp = tcp_usrclosed(tp);
1119         }
1120         return (tcp_output(tp));
1121 }
1122
1123 /*
1124  * Common subroutine to open a TCP connection to remote host specified
1125  * by struct sockaddr_in in mbuf *nam.  Call in_pcbbind to assign a local
1126  * port number if needed.  Call in_pcbladdr to do the routing and to choose
1127  * a local host address (interface).
1128  * Initialize connection parameters and enter SYN-SENT state.
1129  */
1130 static void
1131 tcp_connect(netmsg_t msg)
1132 {
1133         struct socket *so = msg->connect.base.nm_so;
1134         struct sockaddr *nam = msg->connect.nm_nam;
1135         struct thread *td = msg->connect.nm_td;
1136         struct sockaddr_in *sin = (struct sockaddr_in *)nam;
1137         struct sockaddr_in *if_sin = NULL;
1138         struct inpcb *inp;
1139         struct tcpcb *tp;
1140         int error;
1141         uint16_t hash;
1142         lwkt_port_t port;
1143
1144         COMMON_START(so, inp, 0);
1145
1146         /*
1147          * Reconnect our pcb if we have to
1148          */
1149         if (msg->connect.nm_flags & PRUC_RECONNECT) {
1150                 msg->connect.nm_flags &= ~PRUC_RECONNECT;
1151                 TCP_STATE_MIGRATE_END(tp);
1152                 in_pcblink(so->so_pcb, &tcbinfo[mycpu->gd_cpuid]);
1153         } else {
1154                 if (inp->inp_faddr.s_addr != INADDR_ANY) {
1155                         kprintf("inpcb %p, double-connect race\n", inp);
1156                         error = EISCONN;
1157                         if (so->so_state & SS_ISCONNECTING)
1158                                 error = EALREADY;
1159                         goto out;
1160                 }
1161                 KASSERT(inp->inp_fport == 0, ("invalid fport"));
1162         }
1163
1164         /*
1165          * Select local port, if it is not yet selected.
1166          */
1167         if (inp->inp_lport == 0) {
1168                 KKASSERT(inp->inp_laddr.s_addr == INADDR_ANY);
1169
1170                 error = in_pcbladdr(inp, nam, &if_sin, td);
1171                 if (error)
1172                         goto out;
1173                 inp->inp_laddr.s_addr = if_sin->sin_addr.s_addr;
1174                 msg->connect.nm_flags |= PRUC_HASLADDR;
1175
1176                 /*
1177                  * Install faddr/fport earlier, so that when this
1178                  * inpcb is installed on to the lport hash, the
1179                  * 4-tuple contains correct value.
1180                  *
1181                  * NOTE: The faddr/fport will have to be installed
1182                  * after the in_pcbladdr(), which may change them.
1183                  */
1184                 inp->inp_faddr = sin->sin_addr;
1185                 inp->inp_fport = sin->sin_port;
1186
1187                 error = in_pcbbind_remote(inp, nam, td);
1188                 if (error)
1189                         goto out;
1190         }
1191
1192         if ((msg->connect.nm_flags & PRUC_HASLADDR) == 0) {
1193                 /*
1194                  * Rarely used path:
1195                  * This inpcb was bound before this connect.
1196                  */
1197                 error = in_pcbladdr(inp, nam, &if_sin, td);
1198                 if (error)
1199                         goto out;
1200
1201                 /*
1202                  * Save or refresh the faddr/fport, since they may
1203                  * be changed by in_pcbladdr().
1204                  */
1205                 inp->inp_faddr = sin->sin_addr;
1206                 inp->inp_fport = sin->sin_port;
1207         }
1208 #ifdef INVARIANTS
1209         else {
1210                 KASSERT(inp->inp_faddr.s_addr == sin->sin_addr.s_addr,
1211                     ("faddr mismatch for reconnect"));
1212                 KASSERT(inp->inp_fport == sin->sin_port,
1213                     ("fport mismatch for reconnect"));
1214         }
1215 #endif
1216         KKASSERT(inp->inp_socket == so);
1217
1218         hash = tcp_addrhash(sin->sin_addr.s_addr, sin->sin_port,
1219                             (inp->inp_laddr.s_addr != INADDR_ANY ?
1220                              inp->inp_laddr.s_addr : if_sin->sin_addr.s_addr),
1221                             inp->inp_lport);
1222         port = netisr_hashport(hash);
1223
1224         if (port != &curthread->td_msgport) {
1225                 lwkt_msg_t lmsg = &msg->connect.base.lmsg;
1226
1227                 /*
1228                  * in_pcbladdr() may have allocated a route entry for us
1229                  * on the current CPU, but we need a route entry on the
1230                  * inpcb's owner CPU, so free it here.
1231                  */
1232                 in_pcbresetroute(inp);
1233
1234                 /*
1235                  * We are moving the protocol processing port the socket
1236                  * is on, we have to unlink here and re-link on the
1237                  * target cpu.
1238                  */
1239                 in_pcbunlink(so->so_pcb, &tcbinfo[mycpu->gd_cpuid]);
1240                 msg->connect.nm_flags |= PRUC_RECONNECT;
1241                 msg->connect.base.nm_dispatch = tcp_connect;
1242
1243                 TCP_STATE_MIGRATE_START(tp);
1244
1245                 /*
1246                  * Use message put done receipt to change this socket's
1247                  * so_port, i.e. _after_ this message was put onto the
1248                  * target netisr's msgport but _before_ the message could
1249                  * be pulled from the target netisr's msgport, so that:
1250                  * - The upper half (socket code) will not see the new
1251                  *   msgport before this message reaches the new msgport
1252                  *   and messages for this socket will be ordered.
1253                  * - This message will see the new msgport, when its
1254                  *   handler is called in the target netisr.
1255                  *
1256                  * NOTE:
1257                  * We MUST use messege put done receipt to change this
1258                  * socket's so_port:
1259                  * If we changed the so_port in this netisr after the
1260                  * lwkt_forwardmsg (so messages for this socket will be
1261                  * ordered) and changed the so_port in the target netisr
1262                  * at the very beginning of this message's handler, we
1263                  * would suffer so_port overwritten race, given this
1264                  * message might be forwarded again.
1265                  *
1266                  * NOTE:
1267                  * This mechanism depends on that the netisr's msgport
1268                  * is spin msgport (currently it is :).
1269                  *
1270                  * If the upper half saw the new msgport before this
1271                  * message reached the target netisr's msgport, the
1272                  * messages sent from the upper half could reach the new
1273                  * msgport before this message, thus there would be
1274                  * message reordering.  The worst case could be soclose()
1275                  * saw the new msgport and the detach message could reach
1276                  * the new msgport before this message, i.e. the inpcb
1277                  * could have been destroyed when this message was still
1278                  * pending on or on its way to the new msgport.  Other
1279                  * weird cases could also happen, e.g. inpcb->inp_pcbinfo,
1280                  * since we have unlinked this inpcb from the current
1281                  * pcbinfo first.
1282                  */
1283                 lwkt_setmsg_receipt(lmsg, tcp_sosetport);
1284                 lwkt_forwardmsg(port, lmsg);
1285                 /* msg invalid now */
1286                 return;
1287         } else if (msg->connect.nm_flags & PRUC_HELDTD) {
1288                 /*
1289                  * The original thread is no longer needed; release it.
1290                  */
1291                 lwkt_rele(td);
1292                 msg->connect.nm_flags &= ~PRUC_HELDTD;
1293         }
1294         error = tcp_connect_oncpu(tp, msg->connect.nm_sndflags,
1295                                   msg->connect.nm_m, sin, if_sin, hash);
1296         msg->connect.nm_m = NULL;
1297 out:
1298         if (msg->connect.nm_m) {
1299                 m_freem(msg->connect.nm_m);
1300                 msg->connect.nm_m = NULL;
1301         }
1302         if (msg->connect.nm_flags & PRUC_HELDTD)
1303                 lwkt_rele(td);
1304         if (error && (msg->connect.nm_flags & PRUC_ASYNC)) {
1305                 so->so_error = error;
1306                 soisdisconnected(so);
1307         }
1308         lwkt_replymsg(&msg->connect.base.lmsg, error);
1309         /* msg invalid now */
1310 }
1311
1312 #ifdef INET6
1313
1314 static void
1315 tcp6_connect(netmsg_t msg)
1316 {
1317         struct tcpcb *tp;
1318         struct socket *so = msg->connect.base.nm_so;
1319         struct sockaddr *nam = msg->connect.nm_nam;
1320         struct thread *td = msg->connect.nm_td;
1321         struct inpcb *inp;
1322         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)nam;
1323         struct in6_addr *addr6;
1324         lwkt_port_t port;
1325         int error;
1326
1327         COMMON_START(so, inp, 0);
1328
1329         /*
1330          * Reconnect our pcb if we have to
1331          */
1332         if (msg->connect.nm_flags & PRUC_RECONNECT) {
1333                 msg->connect.nm_flags &= ~PRUC_RECONNECT;
1334                 TCP_STATE_MIGRATE_END(tp);
1335                 in_pcblink(so->so_pcb, &tcbinfo[mycpu->gd_cpuid]);
1336         }
1337
1338         /*
1339          * Bind if we have to
1340          */
1341         if (inp->inp_lport == 0) {
1342                 error = in6_pcbbind(inp, NULL, td);
1343                 if (error)
1344                         goto out;
1345         }
1346
1347         /*
1348          * Cannot simply call in_pcbconnect, because there might be an
1349          * earlier incarnation of this same connection still in
1350          * TIME_WAIT state, creating an ADDRINUSE error.
1351          */
1352         error = in6_pcbladdr(inp, nam, &addr6, td);
1353         if (error)
1354                 goto out;
1355
1356         port = tcp6_addrport(); /* XXX hack for now, always cpu0 */
1357
1358         if (port != &curthread->td_msgport) {
1359                 lwkt_msg_t lmsg = &msg->connect.base.lmsg;
1360
1361                 /*
1362                  * in_pcbladdr() may have allocated a route entry for us
1363                  * on the current CPU, but we need a route entry on the
1364                  * inpcb's owner CPU, so free it here.
1365                  */
1366                 in_pcbresetroute(inp);
1367
1368                 in_pcbunlink(so->so_pcb, &tcbinfo[mycpu->gd_cpuid]);
1369                 msg->connect.nm_flags |= PRUC_RECONNECT;
1370                 msg->connect.base.nm_dispatch = tcp6_connect;
1371
1372                 TCP_STATE_MIGRATE_START(tp);
1373
1374                 /* See the related comment in tcp_connect() */
1375                 lwkt_setmsg_receipt(lmsg, tcp_sosetport);
1376                 lwkt_forwardmsg(port, lmsg);
1377                 /* msg invalid now */
1378                 return;
1379         }
1380         error = tcp6_connect_oncpu(tp, msg->connect.nm_sndflags,
1381                                    &msg->connect.nm_m, sin6, addr6);
1382         /* nm_m may still be intact */
1383 out:
1384         if (msg->connect.nm_m) {
1385                 m_freem(msg->connect.nm_m);
1386                 msg->connect.nm_m = NULL;
1387         }
1388         lwkt_replymsg(&msg->connect.base.lmsg, error);
1389         /* msg invalid now */
1390 }
1391
1392 static int
1393 tcp6_connect_oncpu(struct tcpcb *tp, int flags, struct mbuf **mp,
1394                    struct sockaddr_in6 *sin6, struct in6_addr *addr6)
1395 {
1396         struct mbuf *m = *mp;
1397         struct inpcb *inp = tp->t_inpcb;
1398         struct socket *so = inp->inp_socket;
1399         struct inpcb *oinp;
1400
1401         /*
1402          * Cannot simply call in_pcbconnect, because there might be an
1403          * earlier incarnation of this same connection still in
1404          * TIME_WAIT state, creating an ADDRINUSE error.
1405          */
1406         oinp = in6_pcblookup_hash(inp->inp_pcbinfo,
1407                                   &sin6->sin6_addr, sin6->sin6_port,
1408                                   (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr) ?
1409                                       addr6 : &inp->in6p_laddr),
1410                                   inp->inp_lport,  0, NULL);
1411         if (oinp)
1412                 return (EADDRINUSE);
1413
1414         if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr))
1415                 inp->in6p_laddr = *addr6;
1416         inp->in6p_faddr = sin6->sin6_addr;
1417         inp->inp_fport = sin6->sin6_port;
1418         if ((sin6->sin6_flowinfo & IPV6_FLOWINFO_MASK) != 0)
1419                 inp->in6p_flowinfo = sin6->sin6_flowinfo;
1420         in_pcbinsconnhash(inp);
1421
1422         /*
1423          * Now that no more errors can occur, change the protocol processing
1424          * port to the current thread (which is the correct thread).
1425          *
1426          * Create TCP timer message now; we are on the tcpcb's owner
1427          * CPU/thread.
1428          */
1429         tcp_create_timermsg(tp, &curthread->td_msgport);
1430
1431         /* Compute window scaling to request.  */
1432         if (tp->request_r_scale < TCP_MIN_WINSHIFT)
1433                 tp->request_r_scale = TCP_MIN_WINSHIFT;
1434         while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
1435             (TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.ssb_hiwat) {
1436                 tp->request_r_scale++;
1437         }
1438
1439         soisconnecting(so);
1440         tcpstat.tcps_connattempt++;
1441         TCP_STATE_CHANGE(tp, TCPS_SYN_SENT);
1442         tcp_callout_reset(tp, tp->tt_keep, tp->t_keepinit, tcp_timer_keep);
1443         tp->iss = tcp_new_isn(tp);
1444         tcp_sendseqinit(tp);
1445         if (m) {
1446                 ssb_appendstream(&so->so_snd, m);
1447                 *mp = NULL;
1448                 if (flags & PRUS_OOB)
1449                         tp->snd_up = tp->snd_una + so->so_snd.ssb_cc;
1450         }
1451
1452         /*
1453          * Close the send side of the connection after
1454          * the data is sent if flagged.
1455          */
1456         if ((flags & (PRUS_OOB|PRUS_EOF)) == PRUS_EOF) {
1457                 socantsendmore(so);
1458                 tp = tcp_usrclosed(tp);
1459         }
1460         return (tcp_output(tp));
1461 }
1462
1463 #endif /* INET6 */
1464
1465 /*
1466  * The new sockopt interface makes it possible for us to block in the
1467  * copyin/out step (if we take a page fault).  Taking a page fault while
1468  * in a critical section is probably a Bad Thing.  (Since sockets and pcbs
1469  * both now use TSM, there probably isn't any need for this function to
1470  * run in a critical section any more.  This needs more examination.)
1471  */
1472 void
1473 tcp_ctloutput(netmsg_t msg)
1474 {
1475         struct socket *so = msg->base.nm_so;
1476         struct sockopt *sopt = msg->ctloutput.nm_sopt;
1477         struct thread *td = NULL;
1478         int     error, opt, optval, opthz;
1479         struct  inpcb *inp;
1480         struct  tcpcb *tp;
1481
1482         if (msg->ctloutput.nm_flags & PRCO_HELDTD)
1483                 td = sopt->sopt_td;
1484
1485         error = 0;
1486         inp = so->so_pcb;
1487         if (inp == NULL) {
1488                 error = ECONNRESET;
1489                 goto done;
1490         }
1491         tp = intotcpcb(inp);
1492
1493         /* Get socket's owner cpuid hint */
1494         if (sopt->sopt_level == SOL_SOCKET &&
1495             sopt->sopt_dir == SOPT_GET &&
1496             sopt->sopt_name == SO_CPUHINT) {
1497                 if (tp->t_flags & TF_LISTEN) {
1498                         /*
1499                          * Listen sockets owner cpuid is always 0,
1500                          * which does not make sense if SO_REUSEPORT
1501                          * is not set.
1502                          *
1503                          * NOTE: inp_lgrpindex is _not_ assigned in jail.
1504                          */
1505                         if ((so->so_options & SO_REUSEPORT) &&
1506                             inp->inp_lgrpindex >= 0)
1507                                 optval = inp->inp_lgrpindex % netisr_ncpus;
1508                         else
1509                                 optval = -1; /* no hint */
1510                 } else {
1511                         optval = mycpuid;
1512                 }
1513                 soopt_from_kbuf(sopt, &optval, sizeof(optval));
1514                 goto done;
1515         }
1516
1517         if (sopt->sopt_level != IPPROTO_TCP) {
1518                 if (sopt->sopt_level == IPPROTO_IP) {
1519                         switch (sopt->sopt_name) {
1520                         case IP_MULTICAST_IF:
1521                         case IP_MULTICAST_VIF:
1522                         case IP_MULTICAST_TTL:
1523                         case IP_MULTICAST_LOOP:
1524                         case IP_ADD_MEMBERSHIP:
1525                         case IP_DROP_MEMBERSHIP:
1526                                 /*
1527                                  * Multicast does not make sense on
1528                                  * TCP sockets.
1529                                  */
1530                                 error = EOPNOTSUPP;
1531                                 goto done;
1532                         }
1533                 }
1534 #ifdef INET6
1535                 if (INP_CHECK_SOCKAF(so, AF_INET6))
1536                         ip6_ctloutput_dispatch(msg);
1537                 else
1538 #endif /* INET6 */
1539                 ip_ctloutput(msg);
1540                 /* msg invalid now */
1541                 if (td != NULL)
1542                         lwkt_rele(td);
1543                 return;
1544         }
1545
1546         switch (sopt->sopt_dir) {
1547         case SOPT_SET:
1548                 error = soopt_to_kbuf(sopt, &optval, sizeof optval,
1549                                       sizeof optval);
1550                 if (error)
1551                         break;
1552                 switch (sopt->sopt_name) {
1553                 case TCP_FASTKEEP:
1554                         if (optval > 0)
1555                                 tp->t_keepidle = tp->t_keepintvl;
1556                         else
1557                                 tp->t_keepidle = tcp_keepidle;
1558                         tcp_timer_keep_activity(tp, 0);
1559                         break;
1560 #ifdef TCP_SIGNATURE
1561                 case TCP_SIGNATURE_ENABLE:
1562                         if (tp->t_state == TCPS_CLOSED) {
1563                                 /*
1564                                  * This is the only safe state that this
1565                                  * option could be changed.  Some segments
1566                                  * could already have been sent in other
1567                                  * states.
1568                                  */
1569                                 if (optval > 0)
1570                                         tp->t_flags |= TF_SIGNATURE;
1571                                 else
1572                                         tp->t_flags &= ~TF_SIGNATURE;
1573                         } else {
1574                                 error = EOPNOTSUPP;
1575                         }
1576                         break;
1577 #endif /* TCP_SIGNATURE */
1578                 case TCP_NODELAY:
1579                 case TCP_NOOPT:
1580                         switch (sopt->sopt_name) {
1581                         case TCP_NODELAY:
1582                                 opt = TF_NODELAY;
1583                                 break;
1584                         case TCP_NOOPT:
1585                                 opt = TF_NOOPT;
1586                                 break;
1587                         default:
1588                                 opt = 0; /* dead code to fool gcc */
1589                                 break;
1590                         }
1591
1592                         if (optval)
1593                                 tp->t_flags |= opt;
1594                         else
1595                                 tp->t_flags &= ~opt;
1596                         break;
1597
1598                 case TCP_NOPUSH:
1599                         if (tcp_disable_nopush)
1600                                 break;
1601                         if (optval)
1602                                 tp->t_flags |= TF_NOPUSH;
1603                         else {
1604                                 tp->t_flags &= ~TF_NOPUSH;
1605                                 error = tcp_output(tp);
1606                         }
1607                         break;
1608
1609                 case TCP_MAXSEG:
1610                         /*
1611                          * Must be between 0 and maxseg.  If the requested
1612                          * maxseg is too small to satisfy the desired minmss,
1613                          * pump it up (silently so sysctl modifications of
1614                          * minmss do not create unexpected program failures).
1615                          * Handle degenerate cases.
1616                          */
1617                         if (optval > 0 && optval <= tp->t_maxseg) {
1618                                 if (optval + 40 < tcp_minmss) {
1619                                         optval = tcp_minmss - 40;
1620                                         if (optval < 0)
1621                                                 optval = 1;
1622                                 }
1623                                 tp->t_maxseg = optval;
1624                         } else {
1625                                 error = EINVAL;
1626                         }
1627                         break;
1628
1629                 case TCP_KEEPINIT:
1630                         opthz = ((int64_t)optval * hz) / 1000;
1631                         if (opthz >= 1)
1632                                 tp->t_keepinit = opthz;
1633                         else
1634                                 error = EINVAL;
1635                         break;
1636
1637                 case TCP_KEEPIDLE:
1638                         opthz = ((int64_t)optval * hz) / 1000;
1639                         if (opthz >= 1) {
1640                                 tp->t_keepidle = opthz;
1641                                 tcp_timer_keep_activity(tp, 0);
1642                         } else {
1643                                 error = EINVAL;
1644                         }
1645                         break;
1646
1647                 case TCP_KEEPINTVL:
1648                         opthz = ((int64_t)optval * hz) / 1000;
1649                         if (opthz >= 1) {
1650                                 tp->t_keepintvl = opthz;
1651                                 tp->t_maxidle = tp->t_keepintvl * tp->t_keepcnt;
1652                         } else {
1653                                 error = EINVAL;
1654                         }
1655                         break;
1656
1657                 case TCP_KEEPCNT:
1658                         if (optval > 0) {
1659                                 tp->t_keepcnt = optval;
1660                                 tp->t_maxidle = tp->t_keepintvl * tp->t_keepcnt;
1661                         } else {
1662                                 error = EINVAL;
1663                         }
1664                         break;
1665
1666                 default:
1667                         error = ENOPROTOOPT;
1668                         break;
1669                 }
1670                 break;
1671
1672         case SOPT_GET:
1673                 switch (sopt->sopt_name) {
1674 #ifdef TCP_SIGNATURE
1675                 case TCP_SIGNATURE_ENABLE:
1676                         optval = (tp->t_flags & TF_SIGNATURE) ? 1 : 0;
1677                         break;
1678 #endif /* TCP_SIGNATURE */
1679                 case TCP_NODELAY:
1680                         optval = tp->t_flags & TF_NODELAY;
1681                         break;
1682                 case TCP_MAXSEG:
1683                         optval = tp->t_maxseg;
1684                         break;
1685                 case TCP_NOOPT:
1686                         optval = tp->t_flags & TF_NOOPT;
1687                         break;
1688                 case TCP_NOPUSH:
1689                         optval = tp->t_flags & TF_NOPUSH;
1690                         break;
1691                 case TCP_KEEPINIT:
1692                         optval = ((int64_t)tp->t_keepinit * 1000) / hz;
1693                         break;
1694                 case TCP_KEEPIDLE:
1695                         optval = ((int64_t)tp->t_keepidle * 1000) / hz;
1696                         break;
1697                 case TCP_KEEPINTVL:
1698                         optval = ((int64_t)tp->t_keepintvl * 1000) / hz;
1699                         break;
1700                 case TCP_KEEPCNT:
1701                         optval = tp->t_keepcnt;
1702                         break;
1703                 default:
1704                         error = ENOPROTOOPT;
1705                         break;
1706                 }
1707                 if (error == 0)
1708                         soopt_from_kbuf(sopt, &optval, sizeof optval);
1709                 break;
1710         }
1711 done:
1712         if (td != NULL)
1713                 lwkt_rele(td);
1714         lwkt_replymsg(&msg->lmsg, error);
1715 }
1716
1717 struct netmsg_tcp_ctloutput {
1718         struct netmsg_pr_ctloutput ctloutput;
1719         struct sockopt          sopt;
1720         int                     sopt_val;
1721 };
1722
1723 /*
1724  * Allocate netmsg_pr_ctloutput for asynchronous tcp_ctloutput.
1725  */
1726 struct netmsg_pr_ctloutput *
1727 tcp_ctloutmsg(struct sockopt *sopt)
1728 {
1729         struct netmsg_tcp_ctloutput *msg;
1730         int flags = 0, error;
1731
1732         KASSERT(sopt->sopt_dir == SOPT_SET, ("not from ctloutput"));
1733
1734         /* Only small set of options allows asynchronous setting. */
1735         if (sopt->sopt_level != IPPROTO_TCP)
1736                 return NULL;
1737         switch (sopt->sopt_name) {
1738         case TCP_NODELAY:
1739         case TCP_NOOPT:
1740         case TCP_NOPUSH:
1741         case TCP_FASTKEEP:
1742                 break;
1743         default:
1744                 return NULL;
1745         }
1746
1747         msg = kmalloc(sizeof(*msg), M_LWKTMSG, M_WAITOK | M_NULLOK);
1748         if (msg == NULL) {
1749                 /* Fallback to synchronous tcp_ctloutput */
1750                 return NULL;
1751         }
1752
1753         /* Save the sockopt */
1754         msg->sopt = *sopt;
1755
1756         /* Fixup the sopt.sopt_val ptr */
1757         error = sooptcopyin(sopt, &msg->sopt_val,
1758             sizeof(msg->sopt_val), sizeof(msg->sopt_val));
1759         if (error) {
1760                 kfree(msg, M_LWKTMSG);
1761                 return NULL;
1762         }
1763         msg->sopt.sopt_val = &msg->sopt_val;
1764
1765         /* Hold the current thread */
1766         if (msg->sopt.sopt_td != NULL) {
1767                 flags |= PRCO_HELDTD;
1768                 lwkt_hold(msg->sopt.sopt_td);
1769         }
1770
1771         msg->ctloutput.nm_flags = flags;
1772         msg->ctloutput.nm_sopt = &msg->sopt;
1773
1774         return &msg->ctloutput;
1775 }
1776
1777 /*
1778  * tcp_sendspace and tcp_recvspace are the default send and receive window
1779  * sizes, respectively.  These are obsolescent (this information should
1780  * be set by the route).
1781  *
1782  * Use a default that does not require tcp window scaling to be turned
1783  * on.  Individual programs or the administrator can increase the default.
1784  */
1785 u_long  tcp_sendspace = 57344;  /* largest multiple of PAGE_SIZE < 64k */
1786 SYSCTL_INT(_net_inet_tcp, TCPCTL_SENDSPACE, sendspace, CTLFLAG_RW,
1787     &tcp_sendspace , 0, "Maximum outgoing TCP datagram size");
1788 u_long  tcp_recvspace = 57344;  /* largest multiple of PAGE_SIZE < 64k */
1789 SYSCTL_INT(_net_inet_tcp, TCPCTL_RECVSPACE, recvspace, CTLFLAG_RW,
1790     &tcp_recvspace , 0, "Maximum incoming TCP datagram size");
1791
1792 /*
1793  * Attach TCP protocol to socket, allocating internet protocol control
1794  * block, tcp control block, buffer space, and entering CLOSED state.
1795  */
1796 static int
1797 tcp_attach(struct socket *so, struct pru_attach_info *ai)
1798 {
1799         struct inpcb *inp;
1800         int error;
1801         int cpu;
1802 #ifdef INET6
1803         boolean_t isipv6 = INP_CHECK_SOCKAF(so, AF_INET6);
1804 #endif
1805
1806         if (ai != NULL) {
1807                 error = tcp_usr_preattach(so, 0 /* don't care */, ai);
1808                 if (error)
1809                         return (error);
1810         } else {
1811                 /* Post attach; do nothing */
1812         }
1813
1814         cpu = mycpu->gd_cpuid;
1815
1816         /*
1817          * Set the default pcbinfo.  This will likely change when we
1818          * bind/connect.
1819          */
1820         error = in_pcballoc(so, &tcbinfo[cpu]);
1821         if (error)
1822                 return (error);
1823         inp = so->so_pcb;
1824 #ifdef INET6
1825         if (isipv6)
1826                 inp->in6p_hops = -1;    /* use kernel default */
1827 #endif
1828         tcp_newtcpcb(inp);
1829         /* Keep a reference for asynchronized pru_rcvd */
1830         soreference(so);
1831         return (0);
1832 }
1833
1834 /*
1835  * Initiate (or continue) disconnect.
1836  * If embryonic state, just send reset (once).
1837  * If in ``let data drain'' option and linger null, just drop.
1838  * Otherwise (hard), mark socket disconnecting and drop
1839  * current input data; switch states based on user close, and
1840  * send segment to peer (with FIN).
1841  */
1842 static struct tcpcb *
1843 tcp_disconnect(struct tcpcb *tp)
1844 {
1845         struct socket *so = tp->t_inpcb->inp_socket;
1846
1847         if (tp->t_state < TCPS_ESTABLISHED) {
1848                 tp = tcp_close(tp);
1849         } else if ((so->so_options & SO_LINGER) && so->so_linger == 0) {
1850                 tp = tcp_drop(tp, 0);
1851         } else {
1852                 lwkt_gettoken(&so->so_rcv.ssb_token);
1853                 soisdisconnecting(so);
1854                 sbflush(&so->so_rcv.sb);
1855                 tp = tcp_usrclosed(tp);
1856                 if (tp)
1857                         tcp_output(tp);
1858                 lwkt_reltoken(&so->so_rcv.ssb_token);
1859         }
1860         return (tp);
1861 }
1862
1863 /*
1864  * User issued close, and wish to trail through shutdown states:
1865  * if never received SYN, just forget it.  If got a SYN from peer,
1866  * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
1867  * If already got a FIN from peer, then almost done; go to LAST_ACK
1868  * state.  In all other cases, have already sent FIN to peer (e.g.
1869  * after PRU_SHUTDOWN), and just have to play tedious game waiting
1870  * for peer to send FIN or not respond to keep-alives, etc.
1871  * We can let the user exit from the close as soon as the FIN is acked.
1872  */
1873 static struct tcpcb *
1874 tcp_usrclosed(struct tcpcb *tp)
1875 {
1876
1877         switch (tp->t_state) {
1878
1879         case TCPS_CLOSED:
1880         case TCPS_LISTEN:
1881                 TCP_STATE_CHANGE(tp, TCPS_CLOSED);
1882                 tp = tcp_close(tp);
1883                 break;
1884
1885         case TCPS_SYN_SENT:
1886         case TCPS_SYN_RECEIVED:
1887                 tp->t_flags |= TF_NEEDFIN;
1888                 break;
1889
1890         case TCPS_ESTABLISHED:
1891                 TCP_STATE_CHANGE(tp, TCPS_FIN_WAIT_1);
1892                 break;
1893
1894         case TCPS_CLOSE_WAIT:
1895                 TCP_STATE_CHANGE(tp, TCPS_LAST_ACK);
1896                 break;
1897         }
1898         if (tp && tp->t_state >= TCPS_FIN_WAIT_2) {
1899                 soisdisconnected(tp->t_inpcb->inp_socket);
1900                 /* To prevent the connection hanging in FIN_WAIT_2 forever. */
1901                 if (tp->t_state == TCPS_FIN_WAIT_2) {
1902                         tcp_callout_reset(tp, tp->tt_2msl, tp->t_maxidle,
1903                             tcp_timer_2msl);
1904                 }
1905         }
1906         return (tp);
1907 }