sys/net/tun/if_tun.c

   1 /*      $NetBSD: if_tun.c,v 1.14 1994/06/29 06:36:25 cgd Exp $  */
   2
   3 /*
   4  * Copyright (c) 1988, Julian Onions <jpo@cs.nott.ac.uk>
   5  * Nottingham University 1987.
   6  *
   7  * This source may be freely distributed, however I would be interested
   8  * in any changes that are made.
   9  *
  10  * This driver takes packets off the IP i/f and hands them up to a
  11  * user process to have its wicked way with. This driver has it's
  12  * roots in a similar driver written by Phil Cockcroft (formerly) at
  13  * UCL. This driver is based much more on read/write/poll mode of
  14  * operation though.
  15  *
  16  * $FreeBSD: src/sys/net/if_tun.c,v 1.74.2.8 2002/02/13 00:43:11 dillon Exp $
  17  * $DragonFly: src/sys/net/tun/if_tun.c,v 1.25 2005/11/28 17:13:46 dillon Exp $
  18  */
  19
  20 #include "opt_atalk.h"
  21 #include "opt_inet.h"
  22 #include "opt_inet6.h"
  23 #include "opt_ipx.h"
  24
  25 #include <sys/param.h>
  26 #include <sys/proc.h>
  27 #include <sys/systm.h>
  28 #include <sys/mbuf.h>
  29 #include <sys/socket.h>
  30 #include <sys/filio.h>
  31 #include <sys/sockio.h>
  32 #include <sys/thread2.h>
  33 #include <sys/ttycom.h>
  34 #include <sys/poll.h>
  35 #include <sys/signalvar.h>
  36 #include <sys/filedesc.h>
  37 #include <sys/kernel.h>
  38 #include <sys/sysctl.h>
  39 #include <sys/conf.h>
  40 #include <sys/uio.h>
  41 #include <sys/vnode.h>
  42 #include <sys/malloc.h>
  43
  44 #include <net/if.h>
  45 #include <net/if_types.h>
  46 #include <net/ifq_var.h>
  47 #include <net/netisr.h>
  48 #include <net/route.h>
  49
  50 #ifdef INET
  51 #include <netinet/in.h>
  52 #endif
  53
  54 #include <net/bpf.h>
  55
  56 #include "if_tunvar.h"
  57 #include "if_tun.h"
  58
  59 static MALLOC_DEFINE(M_TUN, "tun", "Tunnel Interface");
  60
  61 static void tunattach (void *);
  62 PSEUDO_SET(tunattach, if_tun);
  63
  64 static void tuncreate (dev_t dev);
  65
  66 #define TUNDEBUG        if (tundebug) if_printf
  67 static int tundebug = 0;
  68 SYSCTL_INT(_debug, OID_AUTO, if_tun_debug, CTLFLAG_RW, &tundebug, 0, "");
  69
  70 static int tunoutput (struct ifnet *, struct mbuf *, struct sockaddr *,
  71             struct rtentry *rt);
  72 static int tunifioctl (struct ifnet *, u_long, caddr_t, struct ucred *);
  73 static int tuninit (struct ifnet *);
  74 static void tunstart(struct ifnet *);
  75
  76 static  d_open_t        tunopen;
  77 static  d_close_t       tunclose;
  78 static  d_read_t        tunread;
  79 static  d_write_t       tunwrite;
  80 static  d_ioctl_t       tunioctl;
  81 static  d_poll_t        tunpoll;
  82
  83 #define CDEV_MAJOR 52
  84 static struct cdevsw tun_cdevsw = {
  85         /* name */      "tun",
  86         /* maj */       CDEV_MAJOR,
  87         /* flags */     0,
  88         /* port */      NULL,
  89         /* clone */     NULL,
  90
  91         /* open */      tunopen,
  92         /* close */     tunclose,
  93         /* read */      tunread,
  94         /* write */     tunwrite,
  95         /* ioctl */     tunioctl,
  96         /* poll */      tunpoll,
  97         /* mmap */      nommap,
  98         /* strategy */  nostrategy,
  99         /* dump */      nodump,
 100         /* psize */     nopsize
 101 };
 102
 103 static void
 104 tunattach(void *dummy)
 105 {
 106         cdevsw_add(&tun_cdevsw, 0, 0);
 107 }
 108
 109 static void
 110 tuncreate(dev)
 111         dev_t dev;
 112 {
 113         struct tun_softc *sc;
 114         struct ifnet *ifp;
 115
 116         dev = make_dev(&tun_cdevsw, minor(dev),
 117             UID_UUCP, GID_DIALER, 0600, "tun%d", lminor(dev));
 118
 119         MALLOC(sc, struct tun_softc *, sizeof(*sc), M_TUN, M_WAITOK);
 120         bzero(sc, sizeof *sc);
 121         sc->tun_flags = TUN_INITED;
 122
 123         ifp = &sc->tun_if;
 124         if_initname(ifp, "tun", lminor(dev));
 125         ifp->if_mtu = TUNMTU;
 126         ifp->if_ioctl = tunifioctl;
 127         ifp->if_output = tunoutput;
 128         ifp->if_start = tunstart;
 129         ifp->if_flags = IFF_POINTOPOINT | IFF_MULTICAST;
 130         ifp->if_type = IFT_PPP;
 131         ifq_set_maxlen(&ifp->if_snd, ifqmaxlen);
 132         ifq_set_ready(&ifp->if_snd);
 133         ifp->if_softc = sc;
 134         if_attach(ifp, NULL);
 135         bpfattach(ifp, DLT_NULL, sizeof(u_int));
 136         dev->si_drv1 = sc;
 137 }
 138
 139 /*
 140  * tunnel open - must be superuser & the device must be
 141  * configured in
 142  */
 143 static  int
 144 tunopen(dev_t dev, int flag, int mode, struct thread *td)
 145 {
 146         struct ifnet    *ifp;
 147         struct tun_softc *tp;
 148         int     error;
 149
 150         KKASSERT(td->td_proc);
 151         if ((error = suser(td)) != NULL)
 152                 return (error);
 153
 154         tp = dev->si_drv1;
 155         if (!tp) {
 156                 tuncreate(dev);
 157                 tp = dev->si_drv1;
 158         }
 159         if (tp->tun_flags & TUN_OPEN)
 160                 return EBUSY;
 161         tp->tun_pid = td->td_proc->p_pid;
 162         ifp = &tp->tun_if;
 163         tp->tun_flags |= TUN_OPEN;
 164         TUNDEBUG(ifp, "open\n");
 165         return (0);
 166 }
 167
 168 /*
 169  * tunclose - close the device - mark i/f down & delete
 170  * routing info
 171  */
 172 static  int
 173 tunclose(dev_t dev, int foo, int bar, struct thread *td)
 174 {
 175         struct tun_softc *tp;
 176         struct ifnet    *ifp;
 177
 178         tp = dev->si_drv1;
 179         ifp = &tp->tun_if;
 180
 181         tp->tun_flags &= ~TUN_OPEN;
 182         tp->tun_pid = 0;
 183
 184         /* Junk all pending output. */
 185         lwkt_serialize_enter(ifp->if_serializer);
 186         ifq_purge(&ifp->if_snd);
 187         lwkt_serialize_exit(ifp->if_serializer);
 188
 189         if (ifp->if_flags & IFF_UP) {
 190                 lwkt_serialize_enter(ifp->if_serializer);
 191                 if_down(ifp);
 192                 lwkt_serialize_exit(ifp->if_serializer);
 193         }
 194
 195         if (ifp->if_flags & IFF_RUNNING) {
 196                 struct ifaddr *ifa;
 197
 198                 lwkt_serialize_enter(ifp->if_serializer);
 199                 /* find internet addresses and delete routes */
 200                 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
 201                         if (ifa->ifa_addr->sa_family == AF_INET) {
 202                                 rtinit(ifa, (int)RTM_DELETE,
 203                                     tp->tun_flags & TUN_DSTADDR ? RTF_HOST : 0);
 204                         }
 205                 }
 206                 ifp->if_flags &= ~IFF_RUNNING;
 207                 lwkt_serialize_exit(ifp->if_serializer);
 208         }
 209
 210         funsetown(tp->tun_sigio);
 211         selwakeup(&tp->tun_rsel);
 212
 213         TUNDEBUG(ifp, "closed\n");
 214         return (0);
 215 }
 216
 217 static int
 218 tuninit(ifp)
 219         struct ifnet *ifp;
 220 {
 221         struct tun_softc *tp = ifp->if_softc;
 222         struct ifaddr *ifa;
 223         int error = 0;
 224
 225         TUNDEBUG(ifp, "tuninit\n");
 226
 227         ifp->if_flags |= IFF_UP | IFF_RUNNING;
 228         getmicrotime(&ifp->if_lastchange);
 229
 230         for (ifa = TAILQ_FIRST(&ifp->if_addrhead); ifa;
 231              ifa = TAILQ_NEXT(ifa, ifa_link)) {
 232                 if (ifa->ifa_addr == NULL)
 233                         error = EFAULT;
 234                         /* XXX: Should maybe return straight off? */
 235                 else {
 236 #ifdef INET
 237                         if (ifa->ifa_addr->sa_family == AF_INET) {
 238                             struct sockaddr_in *si;
 239
 240                             si = (struct sockaddr_in *)ifa->ifa_addr;
 241                             if (si->sin_addr.s_addr)
 242                                     tp->tun_flags |= TUN_IASET;
 243
 244                             si = (struct sockaddr_in *)ifa->ifa_dstaddr;
 245                             if (si && si->sin_addr.s_addr)
 246                                     tp->tun_flags |= TUN_DSTADDR;
 247                         }
 248 #endif
 249                 }
 250         }
 251         return (error);
 252 }
 253
 254 /*
 255  * Process an ioctl request.
 256  *
 257  * MPSAFE
 258  */
 259 int
 260 tunifioctl(ifp, cmd, data, cr)
 261         struct ifnet *ifp;
 262         u_long  cmd;
 263         caddr_t data;
 264         struct ucred *cr;
 265 {
 266         struct ifreq *ifr = (struct ifreq *)data;
 267         struct tun_softc *tp = ifp->if_softc;
 268         struct ifstat *ifs;
 269         int error = 0;
 270
 271         switch(cmd) {
 272         case SIOCGIFSTATUS:
 273                 ifs = (struct ifstat *)data;
 274                 if (tp->tun_pid)
 275                         sprintf(ifs->ascii + strlen(ifs->ascii),
 276                             "\tOpened by PID %d\n", tp->tun_pid);
 277                 break;
 278         case SIOCSIFADDR:
 279                 error = tuninit(ifp);
 280                 TUNDEBUG(ifp, "address set, error=%d\n", error);
 281                 break;
 282         case SIOCSIFDSTADDR:
 283                 error = tuninit(ifp);
 284                 TUNDEBUG(ifp, "destination address set, error=%d\n", error);
 285                 break;
 286         case SIOCSIFMTU:
 287                 ifp->if_mtu = ifr->ifr_mtu;
 288                 TUNDEBUG(ifp, "mtu set\n");
 289                 break;
 290         case SIOCSIFFLAGS:
 291         case SIOCADDMULTI:
 292         case SIOCDELMULTI:
 293                 break;
 294         default:
 295                 error = EINVAL;
 296         }
 297         return (error);
 298 }
 299
 300 /*
 301  * tunoutput - queue packets from higher level ready to put out.
 302  *
 303  * MPSAFE
 304  */
 305 int
 306 tunoutput(ifp, m0, dst, rt)
 307         struct ifnet   *ifp;
 308         struct mbuf    *m0;
 309         struct sockaddr *dst;
 310         struct rtentry *rt;
 311 {
 312         struct tun_softc *tp = ifp->if_softc;
 313         int error;
 314         struct altq_pktattr pktattr;
 315
 316         TUNDEBUG(ifp, "tunoutput\n");
 317
 318         if ((tp->tun_flags & TUN_READY) != TUN_READY) {
 319                 TUNDEBUG(ifp, "not ready 0%o\n", tp->tun_flags);
 320                 m_freem (m0);
 321                 return EHOSTDOWN;
 322         }
 323
 324         /*
 325          * if the queueing discipline needs packet classification,
 326          * do it before prepending link headers.
 327          */
 328         ifq_classify(&ifp->if_snd, m0, dst->sa_family, &pktattr);
 329
 330         /* BPF write needs to be handled specially */
 331         if (dst->sa_family == AF_UNSPEC) {
 332                 dst->sa_family = *(mtod(m0, int *));
 333                 m0->m_len -= sizeof(int);
 334                 m0->m_pkthdr.len -= sizeof(int);
 335                 m0->m_data += sizeof(int);
 336         }
 337
 338         if (ifp->if_bpf) {
 339                 /*
 340                  * We need to prepend the address family as
 341                  * a four byte field.
 342                  */
 343                 uint32_t af = dst->sa_family;
 344
 345                 bpf_ptap(ifp->if_bpf, m0, &af, sizeof(af));
 346         }
 347
 348         /* prepend sockaddr? this may abort if the mbuf allocation fails */
 349         if (tp->tun_flags & TUN_LMODE) {
 350                 /* allocate space for sockaddr */
 351                 M_PREPEND(m0, dst->sa_len, MB_DONTWAIT);
 352
 353                 /* if allocation failed drop packet */
 354                 if (m0 == NULL){
 355                         IF_DROP(&ifp->if_snd);
 356                         ifp->if_oerrors++;
 357                         return (ENOBUFS);
 358                 } else {
 359                         bcopy(dst, m0->m_data, dst->sa_len);
 360                 }
 361         }
 362
 363         if (tp->tun_flags & TUN_IFHEAD) {
 364                 /* Prepend the address family */
 365                 M_PREPEND(m0, 4, MB_DONTWAIT);
 366
 367                 /* if allocation failed drop packet */
 368                 if (m0 == NULL){
 369                         IF_DROP(&ifp->if_snd);
 370                         ifp->if_oerrors++;
 371                         return ENOBUFS;
 372                 } else
 373                         *(u_int32_t *)m0->m_data = htonl(dst->sa_family);
 374         } else {
 375 #ifdef INET
 376                 if (dst->sa_family != AF_INET)
 377 #endif
 378                 {
 379                         m_freem(m0);
 380                         return EAFNOSUPPORT;
 381                 }
 382         }
 383
 384         error = ifq_handoff(ifp, m0, &pktattr);
 385         if (error) {
 386                 ifp->if_collisions++;
 387         } else {
 388                 ifp->if_opackets++;
 389                 if (tp->tun_flags & TUN_RWAIT) {
 390                         tp->tun_flags &= ~TUN_RWAIT;
 391                         wakeup((caddr_t)tp);
 392                 }
 393                 get_mplock();
 394                 if (tp->tun_flags & TUN_ASYNC && tp->tun_sigio)
 395                         pgsigio(tp->tun_sigio, SIGIO, 0);
 396                 selwakeup(&tp->tun_rsel);
 397                 rel_mplock();
 398         }
 399         return (error);
 400 }
 401
 402 /*
 403  * the cdevsw interface is now pretty minimal.
 404  */
 405 static  int
 406 tunioctl(dev_t  dev, u_long cmd, caddr_t data, int flag, struct thread *td)
 407 {
 408         struct tun_softc *tp = dev->si_drv1;
 409         struct tuninfo *tunp;
 410
 411         switch (cmd) {
 412         case TUNSIFINFO:
 413                 tunp = (struct tuninfo *)data;
 414                 if (tunp->mtu < IF_MINMTU)
 415                         return (EINVAL);
 416                 tp->tun_if.if_mtu = tunp->mtu;
 417                 tp->tun_if.if_type = tunp->type;
 418                 tp->tun_if.if_baudrate = tunp->baudrate;
 419                 break;
 420         case TUNGIFINFO:
 421                 tunp = (struct tuninfo *)data;
 422                 tunp->mtu = tp->tun_if.if_mtu;
 423                 tunp->type = tp->tun_if.if_type;
 424                 tunp->baudrate = tp->tun_if.if_baudrate;
 425                 break;
 426         case TUNSDEBUG:
 427                 tundebug = *(int *)data;
 428                 break;
 429         case TUNGDEBUG:
 430                 *(int *)data = tundebug;
 431                 break;
 432         case TUNSLMODE:
 433                 if (*(int *)data) {
 434                         tp->tun_flags |= TUN_LMODE;
 435                         tp->tun_flags &= ~TUN_IFHEAD;
 436                 } else
 437                         tp->tun_flags &= ~TUN_LMODE;
 438                 break;
 439         case TUNSIFHEAD:
 440                 if (*(int *)data) {
 441                         tp->tun_flags |= TUN_IFHEAD;
 442                         tp->tun_flags &= ~TUN_LMODE;
 443                 } else
 444                         tp->tun_flags &= ~TUN_IFHEAD;
 445                 break;
 446         case TUNGIFHEAD:
 447                 *(int *)data = (tp->tun_flags & TUN_IFHEAD) ? 1 : 0;
 448                 break;
 449         case TUNSIFMODE:
 450                 /* deny this if UP */
 451                 if (tp->tun_if.if_flags & IFF_UP)
 452                         return(EBUSY);
 453
 454                 switch (*(int *)data & ~IFF_MULTICAST) {
 455                 case IFF_POINTOPOINT:
 456                 case IFF_BROADCAST:
 457                         tp->tun_if.if_flags &= ~(IFF_BROADCAST|IFF_POINTOPOINT);
 458                         tp->tun_if.if_flags |= *(int *)data;
 459                         break;
 460                 default:
 461                         return(EINVAL);
 462                 }
 463                 break;
 464         case TUNSIFPID:
 465                 tp->tun_pid = curproc->p_pid;
 466                 break;
 467         case FIONBIO:
 468                 break;
 469         case FIOASYNC:
 470                 if (*(int *)data)
 471                         tp->tun_flags |= TUN_ASYNC;
 472                 else
 473                         tp->tun_flags &= ~TUN_ASYNC;
 474                 break;
 475         case FIONREAD:
 476                 lwkt_serialize_enter(tp->tun_if.if_serializer);
 477                 if (!ifq_is_empty(&tp->tun_if.if_snd)) {
 478                         struct mbuf *mb;
 479
 480                         mb = ifq_poll(&tp->tun_if.if_snd);
 481                         for( *(int *)data = 0; mb != 0; mb = mb->m_next)
 482                                 *(int *)data += mb->m_len;
 483                 } else {
 484                         *(int *)data = 0;
 485                 }
 486                 lwkt_serialize_exit(tp->tun_if.if_serializer);
 487                 break;
 488         case FIOSETOWN:
 489                 return (fsetown(*(int *)data, &tp->tun_sigio));
 490
 491         case FIOGETOWN:
 492                 *(int *)data = fgetown(tp->tun_sigio);
 493                 return (0);
 494
 495         /* This is deprecated, FIOSETOWN should be used instead. */
 496         case TIOCSPGRP:
 497                 return (fsetown(-(*(int *)data), &tp->tun_sigio));
 498
 499         /* This is deprecated, FIOGETOWN should be used instead. */
 500         case TIOCGPGRP:
 501                 *(int *)data = -fgetown(tp->tun_sigio);
 502                 return (0);
 503
 504         default:
 505                 return (ENOTTY);
 506         }
 507         return (0);
 508 }
 509
 510 /*
 511  * The cdevsw read interface - reads a packet at a time, or at
 512  * least as much of a packet as can be read.
 513  */
 514 static  int
 515 tunread(dev, uio, flag)
 516         dev_t dev;
 517         struct uio *uio;
 518         int flag;
 519 {
 520         struct tun_softc *tp = dev->si_drv1;
 521         struct ifnet    *ifp = &tp->tun_if;
 522         struct mbuf     *m0;
 523         int             error=0, len;
 524
 525         TUNDEBUG(ifp, "read\n");
 526         if ((tp->tun_flags & TUN_READY) != TUN_READY) {
 527                 TUNDEBUG(ifp, "not ready 0%o\n", tp->tun_flags);
 528                 return EHOSTDOWN;
 529         }
 530
 531         tp->tun_flags &= ~TUN_RWAIT;
 532
 533         lwkt_serialize_enter(ifp->if_serializer);
 534
 535         while ((m0 = ifq_dequeue(&ifp->if_snd, NULL)) == NULL) {
 536                 if (flag & IO_NDELAY) {
 537                         lwkt_serialize_exit(ifp->if_serializer);
 538                         return EWOULDBLOCK;
 539                 }
 540                 tp->tun_flags |= TUN_RWAIT;
 541                 if ((error = tsleep(tp, PCATCH, "tunread", 0)) != 0) {
 542                         lwkt_serialize_exit(ifp->if_serializer);
 543                         return error;
 544                 }
 545         }
 546
 547         lwkt_serialize_exit(ifp->if_serializer);
 548
 549         while (m0 && uio->uio_resid > 0 && error == 0) {
 550                 len = min(uio->uio_resid, m0->m_len);
 551                 if (len != 0)
 552                         error = uiomove(mtod(m0, caddr_t), len, uio);
 553                 m0 = m_free(m0);
 554         }
 555
 556         if (m0) {
 557                 TUNDEBUG(ifp, "Dropping mbuf\n");
 558                 m_freem(m0);
 559         }
 560         return error;
 561 }
 562
 563 /*
 564  * the cdevsw write interface - an atomic write is a packet - or else!
 565  */
 566 static  int
 567 tunwrite(dev, uio, flag)
 568         dev_t dev;
 569         struct uio *uio;
 570         int flag;
 571 {
 572         struct tun_softc *tp = dev->si_drv1;
 573         struct ifnet    *ifp = &tp->tun_if;
 574         struct mbuf     *top, **mp, *m;
 575         int             error=0, tlen, mlen;
 576         uint32_t        family;
 577         int             isr;
 578
 579         TUNDEBUG(ifp, "tunwrite\n");
 580
 581         if (uio->uio_resid == 0)
 582                 return 0;
 583
 584         if (uio->uio_resid < 0 || uio->uio_resid > TUNMRU) {
 585                 TUNDEBUG(ifp, "len=%d!\n", uio->uio_resid);
 586                 return EIO;
 587         }
 588         tlen = uio->uio_resid;
 589
 590         /* get a header mbuf */
 591         MGETHDR(m, MB_DONTWAIT, MT_DATA);
 592         if (m == NULL)
 593                 return ENOBUFS;
 594         mlen = MHLEN;
 595
 596         top = 0;
 597         mp = &top;
 598         while (error == 0 && uio->uio_resid > 0) {
 599                 m->m_len = min(mlen, uio->uio_resid);
 600                 error = uiomove(mtod (m, caddr_t), m->m_len, uio);
 601                 *mp = m;
 602                 mp = &m->m_next;
 603                 if (uio->uio_resid > 0) {
 604                         MGET (m, MB_DONTWAIT, MT_DATA);
 605                         if (m == 0) {
 606                                 error = ENOBUFS;
 607                                 break;
 608                         }
 609                         mlen = MLEN;
 610                 }
 611         }
 612         if (error) {
 613                 if (top)
 614                         m_freem (top);
 615                 ifp->if_ierrors++;
 616                 return error;
 617         }
 618
 619         top->m_pkthdr.len = tlen;
 620         top->m_pkthdr.rcvif = ifp;
 621
 622         if (ifp->if_bpf) {
 623                 if (tp->tun_flags & TUN_IFHEAD) {
 624                         /*
 625                          * Conveniently, we already have a 4-byte address
 626                          * family prepended to our packet !
 627                          * Inconveniently, it's in the wrong byte order !
 628                          */
 629                         if ((top = m_pullup(top, sizeof(family))) == NULL)
 630                                 return ENOBUFS;
 631                         *mtod(top, u_int32_t *) =
 632                             ntohl(*mtod(top, u_int32_t *));
 633                         bpf_mtap(ifp->if_bpf, top);
 634                         *mtod(top, u_int32_t *) =
 635                             htonl(*mtod(top, u_int32_t *));
 636                 } else {
 637                         /*
 638                          * We need to prepend the address family as
 639                          * a four byte field.
 640                          */
 641                         static const uint32_t af = AF_INET;
 642
 643                         bpf_ptap(ifp->if_bpf, top, &af, sizeof(af));
 644                 }
 645         }
 646
 647         if (tp->tun_flags & TUN_IFHEAD) {
 648                 if (top->m_len < sizeof(family) &&
 649                     (top = m_pullup(top, sizeof(family))) == NULL)
 650                                 return ENOBUFS;
 651                 family = ntohl(*mtod(top, u_int32_t *));
 652                 m_adj(top, sizeof(family));
 653         } else
 654                 family = AF_INET;
 655
 656         ifp->if_ibytes += top->m_pkthdr.len;
 657         ifp->if_ipackets++;
 658
 659         switch (family) {
 660 #ifdef INET
 661         case AF_INET:
 662                 isr = NETISR_IP;
 663                 break;
 664 #endif
 665 #ifdef INET6
 666         case AF_INET6:
 667                 isr = NETISR_IPV6;
 668                 break;
 669 #endif
 670 #ifdef IPX
 671         case AF_IPX:
 672                 isr = NETISR_IPX;
 673                 break;
 674 #endif
 675 #ifdef NETATALK
 676         case AF_APPLETALK:
 677                 isr = NETISR_ATALK2;
 678                 break;
 679 #endif
 680         default:
 681                 m_freem(m);
 682                 return (EAFNOSUPPORT);
 683         }
 684
 685         netisr_dispatch(isr, top);
 686         return (0);
 687 }
 688
 689 /*
 690  * tunpoll - the poll interface, this is only useful on reads
 691  * really. The write detect always returns true, write never blocks
 692  * anyway, it either accepts the packet or drops it.
 693  */
 694 static  int
 695 tunpoll(dev_t dev, int events, struct thread *td)
 696 {
 697         struct tun_softc *tp = dev->si_drv1;
 698         struct ifnet    *ifp = &tp->tun_if;
 699         int             revents = 0;
 700
 701         TUNDEBUG(ifp, "tunpoll\n");
 702
 703         lwkt_serialize_enter(ifp->if_serializer);
 704
 705         if (events & (POLLIN | POLLRDNORM)) {
 706                 if (!ifq_is_empty(&ifp->if_snd)) {
 707                         TUNDEBUG(ifp, "tunpoll q=%d\n", ifp->if_snd.ifq_len);
 708                         revents |= events & (POLLIN | POLLRDNORM);
 709                 } else {
 710                         TUNDEBUG(ifp, "tunpoll waiting\n");
 711                         selrecord(td, &tp->tun_rsel);
 712                 }
 713         }
 714         if (events & (POLLOUT | POLLWRNORM))
 715                 revents |= events & (POLLOUT | POLLWRNORM);
 716
 717         lwkt_serialize_exit(ifp->if_serializer);
 718
 719         return (revents);
 720 }
 721
 722 /*
 723  * Start packet transmission on the interface.
 724  * when the interface queue is rate-limited by ALTQ,
 725  * if_start is needed to drain packets from the queue in order
 726  * to notify readers when outgoing packets become ready.
 727  */
 728 static void
 729 tunstart(struct ifnet *ifp)
 730 {
 731         struct tun_softc *tp = ifp->if_softc;
 732         struct mbuf *m;
 733
 734         if (!ifq_is_enabled(&ifp->if_snd))
 735                 return;
 736
 737         m = ifq_poll(&ifp->if_snd);
 738         if (m != NULL) {
 739                 if (tp->tun_flags & TUN_RWAIT) {
 740                         tp->tun_flags &= ~TUN_RWAIT;
 741                         wakeup((caddr_t)tp);
 742                 }
 743                 if (tp->tun_flags & TUN_ASYNC && tp->tun_sigio)
 744                         pgsigio(tp->tun_sigio, SIGIO, 0);
 745                 selwakeup(&tp->tun_rsel);
 746         }
 747 }