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  */
  18
  19 #include "use_tun.h"
  20 #include "opt_inet.h"
  21 #include "opt_inet6.h"
  22 #include "opt_ipx.h"
  23
  24 #include <sys/param.h>
  25 #include <sys/proc.h>
  26 #include <sys/priv.h>
  27 #include <sys/systm.h>
  28 #include <sys/mbuf.h>
  29 #include <sys/socket.h>
  30 #include <sys/conf.h>
  31 #include <sys/device.h>
  32 #include <sys/filio.h>
  33 #include <sys/sockio.h>
  34 #include <sys/thread2.h>
  35 #include <sys/ttycom.h>
  36 #include <sys/signalvar.h>
  37 #include <sys/filedesc.h>
  38 #include <sys/kernel.h>
  39 #include <sys/sysctl.h>
  40 #include <sys/uio.h>
  41 #include <sys/vnode.h>
  42 #include <sys/malloc.h>
  43
  44 #include <sys/mplock2.h>
  45
  46 #include <net/if.h>
  47 #include <net/if_types.h>
  48 #include <net/ifq_var.h>
  49 #include <net/netisr.h>
  50 #include <net/route.h>
  51 #include <sys/devfs.h>
  52
  53 #ifdef INET
  54 #include <netinet/in.h>
  55 #endif
  56
  57 #include <net/bpf.h>
  58
  59 #include "if_tunvar.h"
  60 #include "if_tun.h"
  61
  62 static MALLOC_DEFINE(M_TUN, "tun", "Tunnel Interface");
  63
  64 static void tunattach (void *);
  65 PSEUDO_SET(tunattach, if_tun);
  66
  67 static void tuncreate (cdev_t dev);
  68
  69 #define TUNDEBUG        if (tundebug) if_printf
  70 static int tundebug = 0;
  71 SYSCTL_INT(_debug, OID_AUTO, if_tun_debug, CTLFLAG_RW, &tundebug, 0,
  72     "Enable debug output");
  73
  74 static int tunoutput (struct ifnet *, struct mbuf *, struct sockaddr *,
  75             struct rtentry *rt);
  76 static int tunifioctl (struct ifnet *, u_long, caddr_t, struct ucred *);
  77 static int tuninit (struct ifnet *);
  78 static void tunstart(struct ifnet *);
  79 static void tun_filter_detach(struct knote *);
  80 static int tun_filter_read(struct knote *, long);
  81 static int tun_filter_write(struct knote *, long);
  82
  83 static  d_open_t        tunopen;
  84 static  d_close_t       tunclose;
  85 static  d_read_t        tunread;
  86 static  d_write_t       tunwrite;
  87 static  d_ioctl_t       tunioctl;
  88 static  d_kqfilter_t    tunkqfilter;
  89
  90 static d_clone_t tunclone;
  91 DEVFS_DECLARE_CLONE_BITMAP(tun);
  92
  93 #if NTUN <= 1
  94 #define TUN_PREALLOCATED_UNITS  4
  95 #else
  96 #define TUN_PREALLOCATED_UNITS  NTUN
  97 #endif
  98
  99 static struct dev_ops tun_ops = {
 100         { "tun", 0, 0 },
 101         .d_open =       tunopen,
 102         .d_close =      tunclose,
 103         .d_read =       tunread,
 104         .d_write =      tunwrite,
 105         .d_ioctl =      tunioctl,
 106         .d_kqfilter =   tunkqfilter
 107 };
 108
 109 static void
 110 tunattach(void *dummy)
 111 {
 112         int i;
 113         make_autoclone_dev(&tun_ops, &DEVFS_CLONE_BITMAP(tun),
 114                 tunclone, UID_UUCP, GID_DIALER, 0600, "tun");
 115         for (i = 0; i < TUN_PREALLOCATED_UNITS; i++) {
 116                 make_dev(&tun_ops, i, UID_UUCP, GID_DIALER, 0600, "tun%d", i);
 117                 devfs_clone_bitmap_set(&DEVFS_CLONE_BITMAP(tun), i);
 118         }
 119         /* Doesn't need uninit because unloading is not possible, see PSEUDO_SET */
 120 }
 121
 122 static int
 123 tunclone(struct dev_clone_args *ap)
 124 {
 125         int unit;
 126
 127         unit = devfs_clone_bitmap_get(&DEVFS_CLONE_BITMAP(tun), 0);
 128         ap->a_dev = make_only_dev(&tun_ops, unit, UID_UUCP, GID_DIALER, 0600,
 129                                                                 "tun%d", unit);
 130
 131         return 0;
 132 }
 133
 134 static void
 135 tuncreate(cdev_t dev)
 136 {
 137         struct tun_softc *sc;
 138         struct ifnet *ifp;
 139
 140 #if 0
 141         dev = make_dev(&tun_ops, minor(dev),
 142             UID_UUCP, GID_DIALER, 0600, "tun%d", lminor(dev));
 143 #endif
 144
 145         sc = kmalloc(sizeof(*sc), M_TUN, M_WAITOK | M_ZERO);
 146         sc->tun_flags = TUN_INITED;
 147
 148         ifp = &sc->tun_if;
 149         if_initname(ifp, "tun", lminor(dev));
 150         ifp->if_mtu = TUNMTU;
 151         ifp->if_ioctl = tunifioctl;
 152         ifp->if_output = tunoutput;
 153         ifp->if_start = tunstart;
 154         ifp->if_flags = IFF_POINTOPOINT | IFF_MULTICAST;
 155         ifp->if_type = IFT_PPP;
 156         ifq_set_maxlen(&ifp->if_snd, ifqmaxlen);
 157         ifq_set_ready(&ifp->if_snd);
 158         ifp->if_softc = sc;
 159         if_attach(ifp, NULL);
 160         bpfattach(ifp, DLT_NULL, sizeof(u_int));
 161         dev->si_drv1 = sc;
 162 }
 163
 164 /*
 165  * tunnel open - must be superuser & the device must be
 166  * configured in
 167  */
 168 static  int
 169 tunopen(struct dev_open_args *ap)
 170 {
 171         cdev_t dev = ap->a_head.a_dev;
 172         struct ifnet    *ifp;
 173         struct tun_softc *tp;
 174         int     error;
 175
 176         if ((error = priv_check_cred(ap->a_cred, PRIV_ROOT, 0)) != 0)
 177                 return (error);
 178
 179         tp = dev->si_drv1;
 180         if (!tp) {
 181                 tuncreate(dev);
 182                 tp = dev->si_drv1;
 183         }
 184         if (tp->tun_flags & TUN_OPEN)
 185                 return EBUSY;
 186         tp->tun_pid = curproc->p_pid;
 187         ifp = &tp->tun_if;
 188         tp->tun_flags |= TUN_OPEN;
 189         TUNDEBUG(ifp, "open\n");
 190         return (0);
 191 }
 192
 193 /*
 194  * tunclose - close the device - mark i/f down & delete
 195  * routing info
 196  */
 197 static  int
 198 tunclose(struct dev_close_args *ap)
 199 {
 200         cdev_t dev = ap->a_head.a_dev;
 201         struct tun_softc *tp;
 202         struct ifnet    *ifp;
 203
 204         tp = dev->si_drv1;
 205         ifp = &tp->tun_if;
 206
 207         tp->tun_flags &= ~TUN_OPEN;
 208         tp->tun_pid = 0;
 209
 210         /* Junk all pending output. */
 211         ifq_purge(&ifp->if_snd);
 212
 213         if (ifp->if_flags & IFF_UP)
 214                 if_down(ifp);
 215         ifp->if_flags &= ~IFF_RUNNING;
 216         if_purgeaddrs_nolink(ifp);
 217
 218         funsetown(&tp->tun_sigio);
 219         KNOTE(&tp->tun_rkq.ki_note, 0);
 220
 221         TUNDEBUG(ifp, "closed\n");
 222 #if 0
 223         if (dev->si_uminor >= TUN_PREALLOCATED_UNITS) {
 224                 devfs_clone_bitmap_put(&DEVFS_CLONE_BITMAP(tun), dev->si_uminor);
 225         }
 226 #endif
 227         return (0);
 228 }
 229
 230 static int
 231 tuninit(struct ifnet *ifp)
 232 {
 233         struct tun_softc *tp = ifp->if_softc;
 234         struct ifaddr_container *ifac;
 235         int error = 0;
 236
 237         TUNDEBUG(ifp, "tuninit\n");
 238
 239         ifp->if_flags |= IFF_UP | IFF_RUNNING;
 240         getmicrotime(&ifp->if_lastchange);
 241
 242         TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) {
 243                 struct ifaddr *ifa = ifac->ifa;
 244
 245                 if (ifa->ifa_addr == NULL) {
 246                         error = EFAULT;
 247                         /* XXX: Should maybe return straight off? */
 248                 } else {
 249 #ifdef INET
 250                         if (ifa->ifa_addr->sa_family == AF_INET) {
 251                             struct sockaddr_in *si;
 252
 253                             si = (struct sockaddr_in *)ifa->ifa_addr;
 254                             if (si->sin_addr.s_addr)
 255                                     tp->tun_flags |= TUN_IASET;
 256                         }
 257 #endif
 258                 }
 259         }
 260         return (error);
 261 }
 262
 263 /*
 264  * Process an ioctl request.
 265  *
 266  * MPSAFE
 267  */
 268 int
 269 tunifioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
 270 {
 271         struct ifreq *ifr = (struct ifreq *)data;
 272         struct tun_softc *tp = ifp->if_softc;
 273         struct ifstat *ifs;
 274         int error = 0;
 275
 276         switch(cmd) {
 277         case SIOCGIFSTATUS:
 278                 ifs = (struct ifstat *)data;
 279                 if (tp->tun_pid)
 280                         ksprintf(ifs->ascii + strlen(ifs->ascii),
 281                             "\tOpened by PID %d\n", tp->tun_pid);
 282                 break;
 283         case SIOCSIFADDR:
 284                 error = tuninit(ifp);
 285                 TUNDEBUG(ifp, "address set, error=%d\n", error);
 286                 break;
 287         case SIOCSIFDSTADDR:
 288                 error = tuninit(ifp);
 289                 TUNDEBUG(ifp, "destination address set, error=%d\n", error);
 290                 break;
 291         case SIOCSIFMTU:
 292                 ifp->if_mtu = ifr->ifr_mtu;
 293                 TUNDEBUG(ifp, "mtu set\n");
 294                 break;
 295         case SIOCSIFFLAGS:
 296         case SIOCADDMULTI:
 297         case SIOCDELMULTI:
 298                 break;
 299         default:
 300                 error = EINVAL;
 301         }
 302         return (error);
 303 }
 304
 305 /*
 306  * tunoutput - queue packets from higher level ready to put out.
 307  *
 308  * MPSAFE
 309  */
 310 static int
 311 tunoutput_serialized(struct ifnet *ifp, struct mbuf *m0, struct sockaddr *dst,
 312                      struct rtentry *rt)
 313 {
 314         struct tun_softc *tp = ifp->if_softc;
 315         int error;
 316         struct altq_pktattr pktattr;
 317
 318         TUNDEBUG(ifp, "tunoutput\n");
 319
 320         if ((tp->tun_flags & TUN_READY) != TUN_READY) {
 321                 TUNDEBUG(ifp, "not ready 0%o\n", tp->tun_flags);
 322                 m_freem (m0);
 323                 return EHOSTDOWN;
 324         }
 325
 326         /*
 327          * if the queueing discipline needs packet classification,
 328          * do it before prepending link headers.
 329          */
 330         ifq_classify(&ifp->if_snd, m0, dst->sa_family, &pktattr);
 331
 332         /* BPF write needs to be handled specially */
 333         if (dst->sa_family == AF_UNSPEC) {
 334                 dst->sa_family = *(mtod(m0, int *));
 335                 m0->m_len -= sizeof(int);
 336                 m0->m_pkthdr.len -= sizeof(int);
 337                 m0->m_data += sizeof(int);
 338         }
 339
 340         if (ifp->if_bpf) {
 341                 /*
 342                  * We need to prepend the address family as
 343                  * a four byte field.
 344                  */
 345                 uint32_t af = dst->sa_family;
 346
 347                 bpf_ptap(ifp->if_bpf, m0, &af, sizeof(af));
 348         }
 349
 350         /* prepend sockaddr? this may abort if the mbuf allocation fails */
 351         if (tp->tun_flags & TUN_LMODE) {
 352                 /* allocate space for sockaddr */
 353                 M_PREPEND(m0, dst->sa_len, MB_DONTWAIT);
 354
 355                 /* if allocation failed drop packet */
 356                 if (m0 == NULL){
 357                         IF_DROP(&ifp->if_snd);
 358                         ifp->if_oerrors++;
 359                         return (ENOBUFS);
 360                 } else {
 361                         bcopy(dst, m0->m_data, dst->sa_len);
 362                 }
 363         }
 364
 365         if (tp->tun_flags & TUN_IFHEAD) {
 366                 /* Prepend the address family */
 367                 M_PREPEND(m0, 4, MB_DONTWAIT);
 368
 369                 /* if allocation failed drop packet */
 370                 if (m0 == NULL){
 371                         IF_DROP(&ifp->if_snd);
 372                         ifp->if_oerrors++;
 373                         return ENOBUFS;
 374                 } else
 375                         *(u_int32_t *)m0->m_data = htonl(dst->sa_family);
 376         } else {
 377 #ifdef INET
 378                 if (dst->sa_family != AF_INET)
 379 #endif
 380                 {
 381                         m_freem(m0);
 382                         return EAFNOSUPPORT;
 383                 }
 384         }
 385
 386         error = ifq_handoff(ifp, m0, &pktattr);
 387         if (error) {
 388                 ifp->if_collisions++;
 389         } else {
 390                 ifp->if_opackets++;
 391                 if (tp->tun_flags & TUN_RWAIT) {
 392                         tp->tun_flags &= ~TUN_RWAIT;
 393                         wakeup((caddr_t)tp);
 394                 }
 395                 get_mplock();
 396                 if (tp->tun_flags & TUN_ASYNC && tp->tun_sigio)
 397                         pgsigio(tp->tun_sigio, SIGIO, 0);
 398                 rel_mplock();
 399                 ifnet_deserialize_all(ifp);
 400                 KNOTE(&tp->tun_rkq.ki_note, 0);
 401                 ifnet_serialize_all(ifp);
 402         }
 403         return (error);
 404 }
 405
 406 static int
 407 tunoutput(struct ifnet *ifp, struct mbuf *m0, struct sockaddr *dst,
 408           struct rtentry *rt)
 409 {
 410         int error;
 411
 412         ifnet_serialize_all(ifp);
 413         error = tunoutput_serialized(ifp, m0, dst, rt);
 414         ifnet_deserialize_all(ifp);
 415
 416         return error;
 417 }
 418
 419 /*
 420  * the ops interface is now pretty minimal.
 421  */
 422 static  int
 423 tunioctl(struct dev_ioctl_args *ap)
 424 {
 425         cdev_t dev = ap->a_head.a_dev;
 426         struct tun_softc *tp = dev->si_drv1;
 427         struct tuninfo *tunp;
 428
 429         switch (ap->a_cmd) {
 430         case TUNSIFINFO:
 431                 tunp = (struct tuninfo *)ap->a_data;
 432                 if (tunp->mtu < IF_MINMTU)
 433                         return (EINVAL);
 434                 tp->tun_if.if_mtu = tunp->mtu;
 435                 tp->tun_if.if_type = tunp->type;
 436                 tp->tun_if.if_baudrate = tunp->baudrate;
 437                 break;
 438         case TUNGIFINFO:
 439                 tunp = (struct tuninfo *)ap->a_data;
 440                 tunp->mtu = tp->tun_if.if_mtu;
 441                 tunp->type = tp->tun_if.if_type;
 442                 tunp->baudrate = tp->tun_if.if_baudrate;
 443                 break;
 444         case TUNSDEBUG:
 445                 tundebug = *(int *)ap->a_data;
 446                 break;
 447         case TUNGDEBUG:
 448                 *(int *)ap->a_data = tundebug;
 449                 break;
 450         case TUNSLMODE:
 451                 if (*(int *)ap->a_data) {
 452                         tp->tun_flags |= TUN_LMODE;
 453                         tp->tun_flags &= ~TUN_IFHEAD;
 454                 } else
 455                         tp->tun_flags &= ~TUN_LMODE;
 456                 break;
 457         case TUNSIFHEAD:
 458                 if (*(int *)ap->a_data) {
 459                         tp->tun_flags |= TUN_IFHEAD;
 460                         tp->tun_flags &= ~TUN_LMODE;
 461                 } else
 462                         tp->tun_flags &= ~TUN_IFHEAD;
 463                 break;
 464         case TUNGIFHEAD:
 465                 *(int *)ap->a_data = (tp->tun_flags & TUN_IFHEAD) ? 1 : 0;
 466                 break;
 467         case TUNSIFMODE:
 468                 /* deny this if UP */
 469                 if (tp->tun_if.if_flags & IFF_UP)
 470                         return(EBUSY);
 471
 472                 switch (*(int *)ap->a_data & ~IFF_MULTICAST) {
 473                 case IFF_POINTOPOINT:
 474                 case IFF_BROADCAST:
 475                         tp->tun_if.if_flags &= ~(IFF_BROADCAST|IFF_POINTOPOINT);
 476                         tp->tun_if.if_flags |= *(int *)ap->a_data;
 477                         break;
 478                 default:
 479                         return(EINVAL);
 480                 }
 481                 break;
 482         case TUNSIFPID:
 483                 tp->tun_pid = curproc->p_pid;
 484                 break;
 485         case FIOASYNC:
 486                 if (*(int *)ap->a_data)
 487                         tp->tun_flags |= TUN_ASYNC;
 488                 else
 489                         tp->tun_flags &= ~TUN_ASYNC;
 490                 break;
 491         case FIONREAD:
 492                 if (!ifq_is_empty(&tp->tun_if.if_snd)) {
 493                         struct mbuf *mb;
 494
 495                         mb = ifq_poll(&tp->tun_if.if_snd);
 496                         for( *(int *)ap->a_data = 0; mb != NULL; mb = mb->m_next)
 497                                 *(int *)ap->a_data += mb->m_len;
 498                 } else {
 499                         *(int *)ap->a_data = 0;
 500                 }
 501                 break;
 502         case FIOSETOWN:
 503                 return (fsetown(*(int *)ap->a_data, &tp->tun_sigio));
 504
 505         case FIOGETOWN:
 506                 *(int *)ap->a_data = fgetown(&tp->tun_sigio);
 507                 return (0);
 508
 509         /* This is deprecated, FIOSETOWN should be used instead. */
 510         case TIOCSPGRP:
 511                 return (fsetown(-(*(int *)ap->a_data), &tp->tun_sigio));
 512
 513         /* This is deprecated, FIOGETOWN should be used instead. */
 514         case TIOCGPGRP:
 515                 *(int *)ap->a_data = -fgetown(&tp->tun_sigio);
 516                 return (0);
 517
 518         default:
 519                 return (ENOTTY);
 520         }
 521         return (0);
 522 }
 523
 524 /*
 525  * The ops read interface - reads a packet at a time, or at
 526  * least as much of a packet as can be read.
 527  */
 528 static  int
 529 tunread(struct dev_read_args *ap)
 530 {
 531         cdev_t dev = ap->a_head.a_dev;
 532         struct uio *uio = ap->a_uio;
 533         struct tun_softc *tp = dev->si_drv1;
 534         struct ifnet    *ifp = &tp->tun_if;
 535         struct mbuf     *m0;
 536         int             error=0, len;
 537
 538         TUNDEBUG(ifp, "read\n");
 539         if ((tp->tun_flags & TUN_READY) != TUN_READY) {
 540                 TUNDEBUG(ifp, "not ready 0%o\n", tp->tun_flags);
 541                 return EHOSTDOWN;
 542         }
 543
 544         tp->tun_flags &= ~TUN_RWAIT;
 545
 546         ifnet_serialize_all(ifp);
 547
 548         while ((m0 = ifq_dequeue(&ifp->if_snd, NULL)) == NULL) {
 549                 if (ap->a_ioflag & IO_NDELAY) {
 550                         ifnet_deserialize_all(ifp);
 551                         return EWOULDBLOCK;
 552                 }
 553                 tp->tun_flags |= TUN_RWAIT;
 554                 ifnet_deserialize_all(ifp);
 555                 if ((error = tsleep(tp, PCATCH, "tunread", 0)) != 0)
 556                         return error;
 557                 ifnet_serialize_all(ifp);
 558         }
 559
 560         ifnet_deserialize_all(ifp);
 561
 562         while (m0 && uio->uio_resid > 0 && error == 0) {
 563                 len = (int)szmin(uio->uio_resid, m0->m_len);
 564                 if (len != 0)
 565                         error = uiomove(mtod(m0, caddr_t), (size_t)len, uio);
 566                 m0 = m_free(m0);
 567         }
 568
 569         if (m0) {
 570                 TUNDEBUG(ifp, "Dropping mbuf\n");
 571                 m_freem(m0);
 572         }
 573         return error;
 574 }
 575
 576 /*
 577  * the ops write interface - an atomic write is a packet - or else!
 578  */
 579 static  int
 580 tunwrite(struct dev_write_args *ap)
 581 {
 582         cdev_t dev = ap->a_head.a_dev;
 583         struct uio *uio = ap->a_uio;
 584         struct tun_softc *tp = dev->si_drv1;
 585         struct ifnet    *ifp = &tp->tun_if;
 586         struct mbuf     *top, **mp, *m;
 587         int             error=0;
 588         size_t          tlen, mlen;
 589         uint32_t        family;
 590         int             isr;
 591
 592         TUNDEBUG(ifp, "tunwrite\n");
 593
 594         if (uio->uio_resid == 0)
 595                 return 0;
 596
 597         if (uio->uio_resid > TUNMRU) {
 598                 TUNDEBUG(ifp, "len=%zd!\n", uio->uio_resid);
 599                 return EIO;
 600         }
 601         tlen = uio->uio_resid;
 602
 603         /* get a header mbuf */
 604         MGETHDR(m, MB_WAIT, MT_DATA);
 605         if (m == NULL)
 606                 return ENOBUFS;
 607         mlen = MHLEN;
 608
 609         top = NULL;
 610         mp = &top;
 611         while (error == 0 && uio->uio_resid > 0) {
 612                 m->m_len = (int)szmin(mlen, uio->uio_resid);
 613                 error = uiomove(mtod (m, caddr_t), (size_t)m->m_len, uio);
 614                 *mp = m;
 615                 mp = &m->m_next;
 616                 if (uio->uio_resid > 0) {
 617                         MGET (m, MB_WAIT, MT_DATA);
 618                         if (m == NULL) {
 619                                 error = ENOBUFS;
 620                                 break;
 621                         }
 622                         mlen = MLEN;
 623                 }
 624         }
 625         if (error) {
 626                 if (top)
 627                         m_freem (top);
 628                 ifp->if_ierrors++;
 629                 return error;
 630         }
 631
 632         top->m_pkthdr.len = (int)tlen;
 633         top->m_pkthdr.rcvif = ifp;
 634
 635         if (ifp->if_bpf) {
 636                 if (tp->tun_flags & TUN_IFHEAD) {
 637                         /*
 638                          * Conveniently, we already have a 4-byte address
 639                          * family prepended to our packet !
 640                          * Inconveniently, it's in the wrong byte order !
 641                          */
 642                         if ((top = m_pullup(top, sizeof(family))) == NULL)
 643                                 return ENOBUFS;
 644                         *mtod(top, u_int32_t *) =
 645                             ntohl(*mtod(top, u_int32_t *));
 646                         bpf_mtap(ifp->if_bpf, top);
 647                         *mtod(top, u_int32_t *) =
 648                             htonl(*mtod(top, u_int32_t *));
 649                 } else {
 650                         /*
 651                          * We need to prepend the address family as
 652                          * a four byte field.
 653                          */
 654                         static const uint32_t af = AF_INET;
 655
 656                         bpf_ptap(ifp->if_bpf, top, &af, sizeof(af));
 657                 }
 658         }
 659
 660         if (tp->tun_flags & TUN_IFHEAD) {
 661                 if (top->m_len < sizeof(family) &&
 662                     (top = m_pullup(top, sizeof(family))) == NULL)
 663                                 return ENOBUFS;
 664                 family = ntohl(*mtod(top, u_int32_t *));
 665                 m_adj(top, sizeof(family));
 666         } else
 667                 family = AF_INET;
 668
 669         ifp->if_ibytes += top->m_pkthdr.len;
 670         ifp->if_ipackets++;
 671
 672         switch (family) {
 673 #ifdef INET
 674         case AF_INET:
 675                 isr = NETISR_IP;
 676                 break;
 677 #endif
 678 #ifdef INET6
 679         case AF_INET6:
 680                 isr = NETISR_IPV6;
 681                 break;
 682 #endif
 683 #ifdef IPX
 684         case AF_IPX:
 685                 isr = NETISR_IPX;
 686                 break;
 687 #endif
 688         default:
 689                 m_freem(m);
 690                 return (EAFNOSUPPORT);
 691         }
 692
 693         netisr_queue(isr, top);
 694         return (0);
 695 }
 696
 697 static struct filterops tun_read_filtops =
 698         { FILTEROP_ISFD, NULL, tun_filter_detach, tun_filter_read };
 699 static struct filterops tun_write_filtops =
 700         { FILTEROP_ISFD, NULL, tun_filter_detach, tun_filter_write };
 701
 702 static int
 703 tunkqfilter(struct dev_kqfilter_args *ap)
 704 {
 705         cdev_t dev = ap->a_head.a_dev;
 706         struct tun_softc *tp = dev->si_drv1;
 707         struct knote *kn = ap->a_kn;
 708         struct klist *klist;
 709
 710         ap->a_result = 0;
 711         ifnet_serialize_all(&tp->tun_if);
 712
 713         switch (kn->kn_filter) {
 714         case EVFILT_READ:
 715                 kn->kn_fop = &tun_read_filtops;
 716                 kn->kn_hook = (caddr_t)tp;
 717                 break;
 718         case EVFILT_WRITE:
 719                 kn->kn_fop = &tun_write_filtops;
 720                 kn->kn_hook = (caddr_t)tp;
 721                 break;
 722         default:
 723                 ifnet_deserialize_all(&tp->tun_if);
 724                 ap->a_result = EOPNOTSUPP;
 725                 return (0);
 726         }
 727
 728         klist = &tp->tun_rkq.ki_note;
 729         knote_insert(klist, kn);
 730         ifnet_deserialize_all(&tp->tun_if);
 731
 732         return (0);
 733 }
 734
 735 static void
 736 tun_filter_detach(struct knote *kn)
 737 {
 738         struct tun_softc *tp = (struct tun_softc *)kn->kn_hook;
 739         struct klist *klist = &tp->tun_rkq.ki_note;
 740
 741         knote_remove(klist, kn);
 742 }
 743
 744 static int
 745 tun_filter_write(struct knote *kn, long hint)
 746 {
 747         /* Always ready for a write */
 748         return (1);
 749 }
 750
 751 static int
 752 tun_filter_read(struct knote *kn, long hint)
 753 {
 754         struct tun_softc *tp = (struct tun_softc *)kn->kn_hook;
 755         int ready = 0;
 756
 757         ifnet_serialize_all(&tp->tun_if);
 758         if (!ifq_is_empty(&tp->tun_if.if_snd))
 759                 ready = 1;
 760         ifnet_deserialize_all(&tp->tun_if);
 761
 762         return (ready);
 763 }
 764
 765 /*
 766  * Start packet transmission on the interface.
 767  * when the interface queue is rate-limited by ALTQ,
 768  * if_start is needed to drain packets from the queue in order
 769  * to notify readers when outgoing packets become ready.
 770  */
 771 static void
 772 tunstart(struct ifnet *ifp)
 773 {
 774         struct tun_softc *tp = ifp->if_softc;
 775         struct mbuf *m;
 776
 777         if (!ifq_is_enabled(&ifp->if_snd))
 778                 return;
 779
 780         m = ifq_poll(&ifp->if_snd);
 781         if (m != NULL) {
 782                 if (tp->tun_flags & TUN_RWAIT) {
 783                         tp->tun_flags &= ~TUN_RWAIT;
 784                         wakeup((caddr_t)tp);
 785                 }
 786                 if (tp->tun_flags & TUN_ASYNC && tp->tun_sigio)
 787                         pgsigio(tp->tun_sigio, SIGIO, 0);
 788                 ifnet_deserialize_tx(ifp);
 789                 KNOTE(&tp->tun_rkq.ki_note, 0);
 790                 ifnet_serialize_tx(ifp);
 791         }
 792 }