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 1.28 2006/06/13 08:12:03 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_t dev)
 111 {
 112         struct tun_softc *sc;
 113         struct ifnet *ifp;
 114
 115         dev = make_dev(&tun_cdevsw, minor(dev),
 116             UID_UUCP, GID_DIALER, 0600, "tun%d", lminor(dev));
 117
 118         MALLOC(sc, struct tun_softc *, sizeof(*sc), M_TUN, M_WAITOK);
 119         bzero(sc, sizeof *sc);
 120         sc->tun_flags = TUN_INITED;
 121
 122         ifp = &sc->tun_if;
 123         if_initname(ifp, "tun", lminor(dev));
 124         ifp->if_mtu = TUNMTU;
 125         ifp->if_ioctl = tunifioctl;
 126         ifp->if_output = tunoutput;
 127         ifp->if_start = tunstart;
 128         ifp->if_flags = IFF_POINTOPOINT | IFF_MULTICAST;
 129         ifp->if_type = IFT_PPP;
 130         ifq_set_maxlen(&ifp->if_snd, ifqmaxlen);
 131         ifq_set_ready(&ifp->if_snd);
 132         ifp->if_softc = sc;
 133         if_attach(ifp, NULL);
 134         bpfattach(ifp, DLT_NULL, sizeof(u_int));
 135         dev->si_drv1 = sc;
 136 }
 137
 138 /*
 139  * tunnel open - must be superuser & the device must be
 140  * configured in
 141  */
 142 static  int
 143 tunopen(dev_t dev, int flag, int mode, struct thread *td)
 144 {
 145         struct ifnet    *ifp;
 146         struct tun_softc *tp;
 147         int     error;
 148
 149         KKASSERT(td->td_proc);
 150         if ((error = suser(td)) != NULL)
 151                 return (error);
 152
 153         tp = dev->si_drv1;
 154         if (!tp) {
 155                 tuncreate(dev);
 156                 tp = dev->si_drv1;
 157         }
 158         if (tp->tun_flags & TUN_OPEN)
 159                 return EBUSY;
 160         tp->tun_pid = td->td_proc->p_pid;
 161         ifp = &tp->tun_if;
 162         tp->tun_flags |= TUN_OPEN;
 163         TUNDEBUG(ifp, "open\n");
 164         return (0);
 165 }
 166
 167 /*
 168  * tunclose - close the device - mark i/f down & delete
 169  * routing info
 170  */
 171 static  int
 172 tunclose(dev_t dev, int foo, int bar, struct thread *td)
 173 {
 174         struct tun_softc *tp;
 175         struct ifnet    *ifp;
 176
 177         tp = dev->si_drv1;
 178         ifp = &tp->tun_if;
 179
 180         tp->tun_flags &= ~TUN_OPEN;
 181         tp->tun_pid = 0;
 182
 183         /* Junk all pending output. */
 184         lwkt_serialize_enter(ifp->if_serializer);
 185         ifq_purge(&ifp->if_snd);
 186         lwkt_serialize_exit(ifp->if_serializer);
 187
 188         if (ifp->if_flags & IFF_UP) {
 189                 lwkt_serialize_enter(ifp->if_serializer);
 190                 if_down(ifp);
 191                 lwkt_serialize_exit(ifp->if_serializer);
 192         }
 193
 194         if (ifp->if_flags & IFF_RUNNING) {
 195                 struct ifaddr *ifa;
 196
 197                 lwkt_serialize_enter(ifp->if_serializer);
 198                 /* find internet addresses and delete routes */
 199                 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
 200                         if (ifa->ifa_addr->sa_family == AF_INET) {
 201                                 rtinit(ifa, (int)RTM_DELETE,
 202                                     tp->tun_flags & TUN_DSTADDR ? RTF_HOST : 0);
 203                         }
 204                 }
 205                 ifp->if_flags &= ~IFF_RUNNING;
 206                 lwkt_serialize_exit(ifp->if_serializer);
 207         }
 208
 209         funsetown(tp->tun_sigio);
 210         selwakeup(&tp->tun_rsel);
 211
 212         TUNDEBUG(ifp, "closed\n");
 213         return (0);
 214 }
 215
 216 static int
 217 tuninit(struct ifnet *ifp)
 218 {
 219         struct tun_softc *tp = ifp->if_softc;
 220         struct ifaddr *ifa;
 221         int error = 0;
 222
 223         TUNDEBUG(ifp, "tuninit\n");
 224
 225         ifp->if_flags |= IFF_UP | IFF_RUNNING;
 226         getmicrotime(&ifp->if_lastchange);
 227
 228         for (ifa = TAILQ_FIRST(&ifp->if_addrhead); ifa;
 229              ifa = TAILQ_NEXT(ifa, ifa_link)) {
 230                 if (ifa->ifa_addr == NULL)
 231                         error = EFAULT;
 232                         /* XXX: Should maybe return straight off? */
 233                 else {
 234 #ifdef INET
 235                         if (ifa->ifa_addr->sa_family == AF_INET) {
 236                             struct sockaddr_in *si;
 237
 238                             si = (struct sockaddr_in *)ifa->ifa_addr;
 239                             if (si->sin_addr.s_addr)
 240                                     tp->tun_flags |= TUN_IASET;
 241
 242                             si = (struct sockaddr_in *)ifa->ifa_dstaddr;
 243                             if (si && si->sin_addr.s_addr)
 244                                     tp->tun_flags |= TUN_DSTADDR;
 245                         }
 246 #endif
 247                 }
 248         }
 249         return (error);
 250 }
 251
 252 /*
 253  * Process an ioctl request.
 254  *
 255  * MPSAFE
 256  */
 257 int
 258 tunifioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
 259 {
 260         struct ifreq *ifr = (struct ifreq *)data;
 261         struct tun_softc *tp = ifp->if_softc;
 262         struct ifstat *ifs;
 263         int error = 0;
 264
 265         switch(cmd) {
 266         case SIOCGIFSTATUS:
 267                 ifs = (struct ifstat *)data;
 268                 if (tp->tun_pid)
 269                         sprintf(ifs->ascii + strlen(ifs->ascii),
 270                             "\tOpened by PID %d\n", tp->tun_pid);
 271                 break;
 272         case SIOCSIFADDR:
 273                 error = tuninit(ifp);
 274                 TUNDEBUG(ifp, "address set, error=%d\n", error);
 275                 break;
 276         case SIOCSIFDSTADDR:
 277                 error = tuninit(ifp);
 278                 TUNDEBUG(ifp, "destination address set, error=%d\n", error);
 279                 break;
 280         case SIOCSIFMTU:
 281                 ifp->if_mtu = ifr->ifr_mtu;
 282                 TUNDEBUG(ifp, "mtu set\n");
 283                 break;
 284         case SIOCSIFFLAGS:
 285         case SIOCADDMULTI:
 286         case SIOCDELMULTI:
 287                 break;
 288         default:
 289                 error = EINVAL;
 290         }
 291         return (error);
 292 }
 293
 294 /*
 295  * tunoutput - queue packets from higher level ready to put out.
 296  *
 297  * MPSAFE
 298  */
 299 int
 300 tunoutput(struct ifnet *ifp, struct mbuf *m0, struct sockaddr *dst,
 301           struct rtentry *rt)
 302 {
 303         struct tun_softc *tp = ifp->if_softc;
 304         int error;
 305         struct altq_pktattr pktattr;
 306
 307         TUNDEBUG(ifp, "tunoutput\n");
 308
 309         if ((tp->tun_flags & TUN_READY) != TUN_READY) {
 310                 TUNDEBUG(ifp, "not ready 0%o\n", tp->tun_flags);
 311                 m_freem (m0);
 312                 return EHOSTDOWN;
 313         }
 314
 315         /*
 316          * if the queueing discipline needs packet classification,
 317          * do it before prepending link headers.
 318          */
 319         ifq_classify(&ifp->if_snd, m0, dst->sa_family, &pktattr);
 320
 321         /* BPF write needs to be handled specially */
 322         if (dst->sa_family == AF_UNSPEC) {
 323                 dst->sa_family = *(mtod(m0, int *));
 324                 m0->m_len -= sizeof(int);
 325                 m0->m_pkthdr.len -= sizeof(int);
 326                 m0->m_data += sizeof(int);
 327         }
 328
 329         if (ifp->if_bpf) {
 330                 /*
 331                  * We need to prepend the address family as
 332                  * a four byte field.
 333                  */
 334                 uint32_t af = dst->sa_family;
 335
 336                 bpf_ptap(ifp->if_bpf, m0, &af, sizeof(af));
 337         }
 338
 339         /* prepend sockaddr? this may abort if the mbuf allocation fails */
 340         if (tp->tun_flags & TUN_LMODE) {
 341                 /* allocate space for sockaddr */
 342                 M_PREPEND(m0, dst->sa_len, MB_DONTWAIT);
 343
 344                 /* if allocation failed drop packet */
 345                 if (m0 == NULL){
 346                         IF_DROP(&ifp->if_snd);
 347                         ifp->if_oerrors++;
 348                         return (ENOBUFS);
 349                 } else {
 350                         bcopy(dst, m0->m_data, dst->sa_len);
 351                 }
 352         }
 353
 354         if (tp->tun_flags & TUN_IFHEAD) {
 355                 /* Prepend the address family */
 356                 M_PREPEND(m0, 4, MB_DONTWAIT);
 357
 358                 /* if allocation failed drop packet */
 359                 if (m0 == NULL){
 360                         IF_DROP(&ifp->if_snd);
 361                         ifp->if_oerrors++;
 362                         return ENOBUFS;
 363                 } else
 364                         *(u_int32_t *)m0->m_data = htonl(dst->sa_family);
 365         } else {
 366 #ifdef INET
 367                 if (dst->sa_family != AF_INET)
 368 #endif
 369                 {
 370                         m_freem(m0);
 371                         return EAFNOSUPPORT;
 372                 }
 373         }
 374
 375         error = ifq_handoff(ifp, m0, &pktattr);
 376         if (error) {
 377                 ifp->if_collisions++;
 378         } else {
 379                 ifp->if_opackets++;
 380                 if (tp->tun_flags & TUN_RWAIT) {
 381                         tp->tun_flags &= ~TUN_RWAIT;
 382                         wakeup((caddr_t)tp);
 383                 }
 384                 get_mplock();
 385                 if (tp->tun_flags & TUN_ASYNC && tp->tun_sigio)
 386                         pgsigio(tp->tun_sigio, SIGIO, 0);
 387                 selwakeup(&tp->tun_rsel);
 388                 rel_mplock();
 389         }
 390         return (error);
 391 }
 392
 393 /*
 394  * the cdevsw interface is now pretty minimal.
 395  */
 396 static  int
 397 tunioctl(dev_t  dev, u_long cmd, caddr_t data, int flag, struct thread *td)
 398 {
 399         struct tun_softc *tp = dev->si_drv1;
 400         struct tuninfo *tunp;
 401
 402         switch (cmd) {
 403         case TUNSIFINFO:
 404                 tunp = (struct tuninfo *)data;
 405                 if (tunp->mtu < IF_MINMTU)
 406                         return (EINVAL);
 407                 tp->tun_if.if_mtu = tunp->mtu;
 408                 tp->tun_if.if_type = tunp->type;
 409                 tp->tun_if.if_baudrate = tunp->baudrate;
 410                 break;
 411         case TUNGIFINFO:
 412                 tunp = (struct tuninfo *)data;
 413                 tunp->mtu = tp->tun_if.if_mtu;
 414                 tunp->type = tp->tun_if.if_type;
 415                 tunp->baudrate = tp->tun_if.if_baudrate;
 416                 break;
 417         case TUNSDEBUG:
 418                 tundebug = *(int *)data;
 419                 break;
 420         case TUNGDEBUG:
 421                 *(int *)data = tundebug;
 422                 break;
 423         case TUNSLMODE:
 424                 if (*(int *)data) {
 425                         tp->tun_flags |= TUN_LMODE;
 426                         tp->tun_flags &= ~TUN_IFHEAD;
 427                 } else
 428                         tp->tun_flags &= ~TUN_LMODE;
 429                 break;
 430         case TUNSIFHEAD:
 431                 if (*(int *)data) {
 432                         tp->tun_flags |= TUN_IFHEAD;
 433                         tp->tun_flags &= ~TUN_LMODE;
 434                 } else
 435                         tp->tun_flags &= ~TUN_IFHEAD;
 436                 break;
 437         case TUNGIFHEAD:
 438                 *(int *)data = (tp->tun_flags & TUN_IFHEAD) ? 1 : 0;
 439                 break;
 440         case TUNSIFMODE:
 441                 /* deny this if UP */
 442                 if (tp->tun_if.if_flags & IFF_UP)
 443                         return(EBUSY);
 444
 445                 switch (*(int *)data & ~IFF_MULTICAST) {
 446                 case IFF_POINTOPOINT:
 447                 case IFF_BROADCAST:
 448                         tp->tun_if.if_flags &= ~(IFF_BROADCAST|IFF_POINTOPOINT);
 449                         tp->tun_if.if_flags |= *(int *)data;
 450                         break;
 451                 default:
 452                         return(EINVAL);
 453                 }
 454                 break;
 455         case TUNSIFPID:
 456                 tp->tun_pid = curproc->p_pid;
 457                 break;
 458         case FIOASYNC:
 459                 if (*(int *)data)
 460                         tp->tun_flags |= TUN_ASYNC;
 461                 else
 462                         tp->tun_flags &= ~TUN_ASYNC;
 463                 break;
 464         case FIONREAD:
 465                 lwkt_serialize_enter(tp->tun_if.if_serializer);
 466                 if (!ifq_is_empty(&tp->tun_if.if_snd)) {
 467                         struct mbuf *mb;
 468
 469                         mb = ifq_poll(&tp->tun_if.if_snd);
 470                         for( *(int *)data = 0; mb != 0; mb = mb->m_next)
 471                                 *(int *)data += mb->m_len;
 472                 } else {
 473                         *(int *)data = 0;
 474                 }
 475                 lwkt_serialize_exit(tp->tun_if.if_serializer);
 476                 break;
 477         case FIOSETOWN:
 478                 return (fsetown(*(int *)data, &tp->tun_sigio));
 479
 480         case FIOGETOWN:
 481                 *(int *)data = fgetown(tp->tun_sigio);
 482                 return (0);
 483
 484         /* This is deprecated, FIOSETOWN should be used instead. */
 485         case TIOCSPGRP:
 486                 return (fsetown(-(*(int *)data), &tp->tun_sigio));
 487
 488         /* This is deprecated, FIOGETOWN should be used instead. */
 489         case TIOCGPGRP:
 490                 *(int *)data = -fgetown(tp->tun_sigio);
 491                 return (0);
 492
 493         default:
 494                 return (ENOTTY);
 495         }
 496         return (0);
 497 }
 498
 499 /*
 500  * The cdevsw read interface - reads a packet at a time, or at
 501  * least as much of a packet as can be read.
 502  */
 503 static  int
 504 tunread(dev_t dev, struct uio *uio, int flag)
 505 {
 506         struct tun_softc *tp = dev->si_drv1;
 507         struct ifnet    *ifp = &tp->tun_if;
 508         struct mbuf     *m0;
 509         int             error=0, len;
 510
 511         TUNDEBUG(ifp, "read\n");
 512         if ((tp->tun_flags & TUN_READY) != TUN_READY) {
 513                 TUNDEBUG(ifp, "not ready 0%o\n", tp->tun_flags);
 514                 return EHOSTDOWN;
 515         }
 516
 517         tp->tun_flags &= ~TUN_RWAIT;
 518
 519         lwkt_serialize_enter(ifp->if_serializer);
 520
 521         while ((m0 = ifq_dequeue(&ifp->if_snd, NULL)) == NULL) {
 522                 if (flag & IO_NDELAY) {
 523                         lwkt_serialize_exit(ifp->if_serializer);
 524                         return EWOULDBLOCK;
 525                 }
 526                 tp->tun_flags |= TUN_RWAIT;
 527                 lwkt_serialize_exit(ifp->if_serializer);
 528                 if ((error = tsleep(tp, PCATCH, "tunread", 0)) != 0)
 529                         return error;
 530                 lwkt_serialize_enter(ifp->if_serializer);
 531         }
 532
 533         lwkt_serialize_exit(ifp->if_serializer);
 534
 535         while (m0 && uio->uio_resid > 0 && error == 0) {
 536                 len = min(uio->uio_resid, m0->m_len);
 537                 if (len != 0)
 538                         error = uiomove(mtod(m0, caddr_t), len, uio);
 539                 m0 = m_free(m0);
 540         }
 541
 542         if (m0) {
 543                 TUNDEBUG(ifp, "Dropping mbuf\n");
 544                 m_freem(m0);
 545         }
 546         return error;
 547 }
 548
 549 /*
 550  * the cdevsw write interface - an atomic write is a packet - or else!
 551  */
 552 static  int
 553 tunwrite(dev_t dev, struct uio *uio, int flag)
 554 {
 555         struct tun_softc *tp = dev->si_drv1;
 556         struct ifnet    *ifp = &tp->tun_if;
 557         struct mbuf     *top, **mp, *m;
 558         int             error=0, tlen, mlen;
 559         uint32_t        family;
 560         int             isr;
 561
 562         TUNDEBUG(ifp, "tunwrite\n");
 563
 564         if (uio->uio_resid == 0)
 565                 return 0;
 566
 567         if (uio->uio_resid < 0 || uio->uio_resid > TUNMRU) {
 568                 TUNDEBUG(ifp, "len=%d!\n", uio->uio_resid);
 569                 return EIO;
 570         }
 571         tlen = uio->uio_resid;
 572
 573         /* get a header mbuf */
 574         MGETHDR(m, MB_DONTWAIT, MT_DATA);
 575         if (m == NULL)
 576                 return ENOBUFS;
 577         mlen = MHLEN;
 578
 579         top = 0;
 580         mp = &top;
 581         while (error == 0 && uio->uio_resid > 0) {
 582                 m->m_len = min(mlen, uio->uio_resid);
 583                 error = uiomove(mtod (m, caddr_t), m->m_len, uio);
 584                 *mp = m;
 585                 mp = &m->m_next;
 586                 if (uio->uio_resid > 0) {
 587                         MGET (m, MB_DONTWAIT, MT_DATA);
 588                         if (m == 0) {
 589                                 error = ENOBUFS;
 590                                 break;
 591                         }
 592                         mlen = MLEN;
 593                 }
 594         }
 595         if (error) {
 596                 if (top)
 597                         m_freem (top);
 598                 ifp->if_ierrors++;
 599                 return error;
 600         }
 601
 602         top->m_pkthdr.len = tlen;
 603         top->m_pkthdr.rcvif = ifp;
 604
 605         if (ifp->if_bpf) {
 606                 if (tp->tun_flags & TUN_IFHEAD) {
 607                         /*
 608                          * Conveniently, we already have a 4-byte address
 609                          * family prepended to our packet !
 610                          * Inconveniently, it's in the wrong byte order !
 611                          */
 612                         if ((top = m_pullup(top, sizeof(family))) == NULL)
 613                                 return ENOBUFS;
 614                         *mtod(top, u_int32_t *) =
 615                             ntohl(*mtod(top, u_int32_t *));
 616                         bpf_mtap(ifp->if_bpf, top);
 617                         *mtod(top, u_int32_t *) =
 618                             htonl(*mtod(top, u_int32_t *));
 619                 } else {
 620                         /*
 621                          * We need to prepend the address family as
 622                          * a four byte field.
 623                          */
 624                         static const uint32_t af = AF_INET;
 625
 626                         bpf_ptap(ifp->if_bpf, top, &af, sizeof(af));
 627                 }
 628         }
 629
 630         if (tp->tun_flags & TUN_IFHEAD) {
 631                 if (top->m_len < sizeof(family) &&
 632                     (top = m_pullup(top, sizeof(family))) == NULL)
 633                                 return ENOBUFS;
 634                 family = ntohl(*mtod(top, u_int32_t *));
 635                 m_adj(top, sizeof(family));
 636         } else
 637                 family = AF_INET;
 638
 639         ifp->if_ibytes += top->m_pkthdr.len;
 640         ifp->if_ipackets++;
 641
 642         switch (family) {
 643 #ifdef INET
 644         case AF_INET:
 645                 isr = NETISR_IP;
 646                 break;
 647 #endif
 648 #ifdef INET6
 649         case AF_INET6:
 650                 isr = NETISR_IPV6;
 651                 break;
 652 #endif
 653 #ifdef IPX
 654         case AF_IPX:
 655                 isr = NETISR_IPX;
 656                 break;
 657 #endif
 658 #ifdef NETATALK
 659         case AF_APPLETALK:
 660                 isr = NETISR_ATALK2;
 661                 break;
 662 #endif
 663         default:
 664                 m_freem(m);
 665                 return (EAFNOSUPPORT);
 666         }
 667
 668         netisr_dispatch(isr, top);
 669         return (0);
 670 }
 671
 672 /*
 673  * tunpoll - the poll interface, this is only useful on reads
 674  * really. The write detect always returns true, write never blocks
 675  * anyway, it either accepts the packet or drops it.
 676  */
 677 static  int
 678 tunpoll(dev_t dev, int events, struct thread *td)
 679 {
 680         struct tun_softc *tp = dev->si_drv1;
 681         struct ifnet    *ifp = &tp->tun_if;
 682         int             revents = 0;
 683
 684         TUNDEBUG(ifp, "tunpoll\n");
 685
 686         lwkt_serialize_enter(ifp->if_serializer);
 687
 688         if (events & (POLLIN | POLLRDNORM)) {
 689                 if (!ifq_is_empty(&ifp->if_snd)) {
 690                         TUNDEBUG(ifp, "tunpoll q=%d\n", ifp->if_snd.ifq_len);
 691                         revents |= events & (POLLIN | POLLRDNORM);
 692                 } else {
 693                         TUNDEBUG(ifp, "tunpoll waiting\n");
 694                         selrecord(td, &tp->tun_rsel);
 695                 }
 696         }
 697         if (events & (POLLOUT | POLLWRNORM))
 698                 revents |= events & (POLLOUT | POLLWRNORM);
 699
 700         lwkt_serialize_exit(ifp->if_serializer);
 701
 702         return (revents);
 703 }
 704
 705 /*
 706  * Start packet transmission on the interface.
 707  * when the interface queue is rate-limited by ALTQ,
 708  * if_start is needed to drain packets from the queue in order
 709  * to notify readers when outgoing packets become ready.
 710  */
 711 static void
 712 tunstart(struct ifnet *ifp)
 713 {
 714         struct tun_softc *tp = ifp->if_softc;
 715         struct mbuf *m;
 716
 717         if (!ifq_is_enabled(&ifp->if_snd))
 718                 return;
 719
 720         m = ifq_poll(&ifp->if_snd);
 721         if (m != NULL) {
 722                 if (tp->tun_flags & TUN_RWAIT) {
 723                         tp->tun_flags &= ~TUN_RWAIT;
 724                         wakeup((caddr_t)tp);
 725                 }
 726                 if (tp->tun_flags & TUN_ASYNC && tp->tun_sigio)
 727                         pgsigio(tp->tun_sigio, SIGIO, 0);
 728                 selwakeup(&tp->tun_rsel);
 729         }
 730 }