sys/net/bpf.c

   1 /*
   2  * Copyright (c) 1990, 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from the Stanford/CMU enet packet filter,
   6  * (net/enet.c) distributed as part of 4.3BSD, and code contributed
   7  * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence
   8  * Berkeley Laboratory.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  *
  38  *      @(#)bpf.c       8.2 (Berkeley) 3/28/94
  39  *
  40  * $FreeBSD: src/sys/net/bpf.c,v 1.59.2.12 2002/04/14 21:41:48 luigi Exp $
  41  * $DragonFly: src/sys/net/bpf.c,v 1.50 2008/09/23 11:28:49 sephe Exp $
  42  */
  43
  44 #include "use_bpf.h"
  45
  46 #include <sys/param.h>
  47 #include <sys/systm.h>
  48 #include <sys/conf.h>
  49 #include <sys/device.h>
  50 #include <sys/malloc.h>
  51 #include <sys/mbuf.h>
  52 #include <sys/time.h>
  53 #include <sys/proc.h>
  54 #include <sys/signalvar.h>
  55 #include <sys/filio.h>
  56 #include <sys/sockio.h>
  57 #include <sys/ttycom.h>
  58 #include <sys/filedesc.h>
  59
  60 #include <sys/poll.h>
  61
  62 #include <sys/socket.h>
  63 #include <sys/vnode.h>
  64
  65 #include <sys/thread2.h>
  66
  67 #include <net/if.h>
  68 #include <net/bpf.h>
  69 #include <net/bpfdesc.h>
  70 #include <net/netmsg2.h>
  71
  72 #include <netinet/in.h>
  73 #include <netinet/if_ether.h>
  74 #include <sys/kernel.h>
  75 #include <sys/sysctl.h>
  76
  77 struct netmsg_bpf_output {
  78         struct netmsg   nm_netmsg;
  79         struct mbuf     *nm_mbuf;
  80         struct ifnet    *nm_ifp;
  81         struct sockaddr *nm_dst;
  82 };
  83
  84 MALLOC_DEFINE(M_BPF, "BPF", "BPF data");
  85
  86 #if NBPF > 0
  87
  88 /*
  89  * The default read buffer size is patchable.
  90  */
  91 static int bpf_bufsize = BPF_DEFAULTBUFSIZE;
  92 SYSCTL_INT(_debug, OID_AUTO, bpf_bufsize, CTLFLAG_RW,
  93            &bpf_bufsize, 0, "");
  94 int bpf_maxbufsize = BPF_MAXBUFSIZE;
  95 SYSCTL_INT(_debug, OID_AUTO, bpf_maxbufsize, CTLFLAG_RW,
  96            &bpf_maxbufsize, 0, "");
  97
  98 /*
  99  *  bpf_iflist is the list of interfaces; each corresponds to an ifnet
 100  */
 101 static struct bpf_if    *bpf_iflist;
 102
 103 static int      bpf_allocbufs(struct bpf_d *);
 104 static void     bpf_attachd(struct bpf_d *d, struct bpf_if *bp);
 105 static void     bpf_detachd(struct bpf_d *d);
 106 static void     bpf_resetd(struct bpf_d *);
 107 static void     bpf_freed(struct bpf_d *);
 108 static void     bpf_mcopy(const void *, void *, size_t);
 109 static int      bpf_movein(struct uio *, int, struct mbuf **,
 110                            struct sockaddr *, int *, struct bpf_insn *);
 111 static int      bpf_setif(struct bpf_d *, struct ifreq *);
 112 static void     bpf_timed_out(void *);
 113 static void     bpf_wakeup(struct bpf_d *);
 114 static void     catchpacket(struct bpf_d *, u_char *, u_int, u_int,
 115                             void (*)(const void *, void *, size_t),
 116                             const struct timeval *);
 117 static int      bpf_setf(struct bpf_d *, struct bpf_program *, u_long cmd);
 118 static int      bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *);
 119 static int      bpf_setdlt(struct bpf_d *, u_int);
 120 static void     bpf_drvinit(void *unused);
 121
 122 static d_open_t         bpfopen;
 123 static d_close_t        bpfclose;
 124 static d_read_t         bpfread;
 125 static d_write_t        bpfwrite;
 126 static d_ioctl_t        bpfioctl;
 127 static d_poll_t         bpfpoll;
 128
 129 #define CDEV_MAJOR 23
 130 static struct dev_ops bpf_ops = {
 131         { "bpf", CDEV_MAJOR, 0 },
 132         .d_open =       bpfopen,
 133         .d_close =      bpfclose,
 134         .d_read =       bpfread,
 135         .d_write =      bpfwrite,
 136         .d_ioctl =      bpfioctl,
 137         .d_poll =       bpfpoll,
 138 };
 139
 140
 141 static int
 142 bpf_movein(struct uio *uio, int linktype, struct mbuf **mp,
 143            struct sockaddr *sockp, int *datlen, struct bpf_insn *wfilter)
 144 {
 145         struct mbuf *m;
 146         int error;
 147         int len;
 148         int hlen;
 149         int slen;
 150
 151         *datlen = 0;
 152         *mp = NULL;
 153
 154         /*
 155          * Build a sockaddr based on the data link layer type.
 156          * We do this at this level because the ethernet header
 157          * is copied directly into the data field of the sockaddr.
 158          * In the case of SLIP, there is no header and the packet
 159          * is forwarded as is.
 160          * Also, we are careful to leave room at the front of the mbuf
 161          * for the link level header.
 162          */
 163         switch (linktype) {
 164         case DLT_SLIP:
 165                 sockp->sa_family = AF_INET;
 166                 hlen = 0;
 167                 break;
 168
 169         case DLT_EN10MB:
 170                 sockp->sa_family = AF_UNSPEC;
 171                 /* XXX Would MAXLINKHDR be better? */
 172                 hlen = sizeof(struct ether_header);
 173                 break;
 174
 175         case DLT_RAW:
 176         case DLT_NULL:
 177                 sockp->sa_family = AF_UNSPEC;
 178                 hlen = 0;
 179                 break;
 180
 181         case DLT_ATM_RFC1483:
 182                 /*
 183                  * en atm driver requires 4-byte atm pseudo header.
 184                  * though it isn't standard, vpi:vci needs to be
 185                  * specified anyway.
 186                  */
 187                 sockp->sa_family = AF_UNSPEC;
 188                 hlen = 12;      /* XXX 4(ATM_PH) + 3(LLC) + 5(SNAP) */
 189                 break;
 190
 191         case DLT_PPP:
 192                 sockp->sa_family = AF_UNSPEC;
 193                 hlen = 4;       /* This should match PPP_HDRLEN */
 194                 break;
 195
 196         default:
 197                 return(EIO);
 198         }
 199
 200         len = uio->uio_resid;
 201         *datlen = len - hlen;
 202         if ((unsigned)len > MCLBYTES)
 203                 return(EIO);
 204
 205         m = m_getl(len, MB_WAIT, MT_DATA, M_PKTHDR, NULL);
 206         if (m == NULL)
 207                 return(ENOBUFS);
 208         m->m_pkthdr.len = m->m_len = len;
 209         m->m_pkthdr.rcvif = NULL;
 210         *mp = m;
 211
 212         if (m->m_len < hlen) {
 213                 error = EPERM;
 214                 goto bad;
 215         }
 216
 217         error = uiomove(mtod(m, u_char *), len, uio);
 218         if (error)
 219                 goto bad;
 220
 221         slen = bpf_filter(wfilter, mtod(m, u_char *), len, len);
 222         if (slen == 0) {
 223                 error = EPERM;
 224                 goto bad;
 225         }
 226
 227         /*
 228          * Make room for link header, and copy it to sockaddr.
 229          */
 230         if (hlen != 0) {
 231                 bcopy(m->m_data, sockp->sa_data, hlen);
 232                 m->m_pkthdr.len -= hlen;
 233                 m->m_len -= hlen;
 234                 m->m_data += hlen; /* XXX */
 235         }
 236         return (0);
 237 bad:
 238         m_freem(m);
 239         return(error);
 240 }
 241
 242 /*
 243  * Attach file to the bpf interface, i.e. make d listen on bp.
 244  * Must be called at splimp.
 245  */
 246 static void
 247 bpf_attachd(struct bpf_d *d, struct bpf_if *bp)
 248 {
 249         /*
 250          * Point d at bp, and add d to the interface's list of listeners.
 251          * Finally, point the driver's bpf cookie at the interface so
 252          * it will divert packets to bpf.
 253          */
 254         d->bd_bif = bp;
 255         SLIST_INSERT_HEAD(&bp->bif_dlist, d, bd_next);
 256         *bp->bif_driverp = bp;
 257 }
 258
 259 /*
 260  * Detach a file from its interface.
 261  */
 262 static void
 263 bpf_detachd(struct bpf_d *d)
 264 {
 265         int error;
 266         struct bpf_if *bp;
 267         struct ifnet *ifp;
 268
 269         bp = d->bd_bif;
 270         ifp = bp->bif_ifp;
 271
 272         /* Remove d from the interface's descriptor list. */
 273         SLIST_REMOVE(&bp->bif_dlist, d, bpf_d, bd_next);
 274
 275         if (SLIST_EMPTY(&bp->bif_dlist)) {
 276                 /*
 277                  * Let the driver know that there are no more listeners.
 278                  */
 279                 *bp->bif_driverp = NULL;
 280         }
 281         d->bd_bif = NULL;
 282         /*
 283          * Check if this descriptor had requested promiscuous mode.
 284          * If so, turn it off.
 285          */
 286         if (d->bd_promisc) {
 287                 d->bd_promisc = 0;
 288                 error = ifpromisc(ifp, 0);
 289                 if (error != 0 && error != ENXIO) {
 290                         /*
 291                          * ENXIO can happen if a pccard is unplugged,
 292                          * Something is really wrong if we were able to put
 293                          * the driver into promiscuous mode, but can't
 294                          * take it out.
 295                          */
 296                         if_printf(ifp, "bpf_detach: ifpromisc failed(%d)\n",
 297                                   error);
 298                 }
 299         }
 300 }
 301
 302 /*
 303  * Open ethernet device.  Returns ENXIO for illegal minor device number,
 304  * EBUSY if file is open by another process.
 305  */
 306 /* ARGSUSED */
 307 static int
 308 bpfopen(struct dev_open_args *ap)
 309 {
 310         cdev_t dev = ap->a_head.a_dev;
 311         struct bpf_d *d;
 312
 313         if (ap->a_cred->cr_prison)
 314                 return(EPERM);
 315
 316         d = dev->si_drv1;
 317         /*
 318          * Each minor can be opened by only one process.  If the requested
 319          * minor is in use, return EBUSY.
 320          */
 321         if (d != NULL)
 322                 return(EBUSY);
 323         make_dev(&bpf_ops, minor(dev), 0, 0, 0600, "bpf%d", lminor(dev));
 324         MALLOC(d, struct bpf_d *, sizeof *d, M_BPF, M_WAITOK | M_ZERO);
 325         dev->si_drv1 = d;
 326         d->bd_bufsize = bpf_bufsize;
 327         d->bd_sig = SIGIO;
 328         d->bd_seesent = 1;
 329         callout_init(&d->bd_callout);
 330         return(0);
 331 }
 332
 333 /*
 334  * Close the descriptor by detaching it from its interface,
 335  * deallocating its buffers, and marking it free.
 336  */
 337 /* ARGSUSED */
 338 static int
 339 bpfclose(struct dev_close_args *ap)
 340 {
 341         cdev_t dev = ap->a_head.a_dev;
 342         struct bpf_d *d = dev->si_drv1;
 343
 344         funsetown(d->bd_sigio);
 345         crit_enter();
 346         if (d->bd_state == BPF_WAITING)
 347                 callout_stop(&d->bd_callout);
 348         d->bd_state = BPF_IDLE;
 349         if (d->bd_bif != NULL)
 350                 bpf_detachd(d);
 351         crit_exit();
 352         bpf_freed(d);
 353         dev->si_drv1 = NULL;
 354         kfree(d, M_BPF);
 355
 356         return(0);
 357 }
 358
 359 /*
 360  * Rotate the packet buffers in descriptor d.  Move the store buffer
 361  * into the hold slot, and the free buffer into the store slot.
 362  * Zero the length of the new store buffer.
 363  */
 364 #define ROTATE_BUFFERS(d) \
 365         (d)->bd_hbuf = (d)->bd_sbuf; \
 366         (d)->bd_hlen = (d)->bd_slen; \
 367         (d)->bd_sbuf = (d)->bd_fbuf; \
 368         (d)->bd_slen = 0; \
 369         (d)->bd_fbuf = NULL;
 370 /*
 371  *  bpfread - read next chunk of packets from buffers
 372  */
 373 static int
 374 bpfread(struct dev_read_args *ap)
 375 {
 376         cdev_t dev = ap->a_head.a_dev;
 377         struct bpf_d *d = dev->si_drv1;
 378         int timed_out;
 379         int error;
 380
 381         /*
 382          * Restrict application to use a buffer the same size as
 383          * as kernel buffers.
 384          */
 385         if (ap->a_uio->uio_resid != d->bd_bufsize)
 386                 return(EINVAL);
 387
 388         crit_enter();
 389         if (d->bd_state == BPF_WAITING)
 390                 callout_stop(&d->bd_callout);
 391         timed_out = (d->bd_state == BPF_TIMED_OUT);
 392         d->bd_state = BPF_IDLE;
 393         /*
 394          * If the hold buffer is empty, then do a timed sleep, which
 395          * ends when the timeout expires or when enough packets
 396          * have arrived to fill the store buffer.
 397          */
 398         while (d->bd_hbuf == NULL) {
 399                 if ((d->bd_immediate || timed_out) && d->bd_slen != 0) {
 400                         /*
 401                          * A packet(s) either arrived since the previous
 402                          * read or arrived while we were asleep.
 403                          * Rotate the buffers and return what's here.
 404                          */
 405                         ROTATE_BUFFERS(d);
 406                         break;
 407                 }
 408
 409                 /*
 410                  * No data is available, check to see if the bpf device
 411                  * is still pointed at a real interface.  If not, return
 412                  * ENXIO so that the userland process knows to rebind
 413                  * it before using it again.
 414                  */
 415                 if (d->bd_bif == NULL) {
 416                         crit_exit();
 417                         return(ENXIO);
 418                 }
 419
 420                 if (ap->a_ioflag & IO_NDELAY) {
 421                         crit_exit();
 422                         return(EWOULDBLOCK);
 423                 }
 424                 error = tsleep(d, PCATCH, "bpf", d->bd_rtout);
 425                 if (error == EINTR || error == ERESTART) {
 426                         crit_exit();
 427                         return(error);
 428                 }
 429                 if (error == EWOULDBLOCK) {
 430                         /*
 431                          * On a timeout, return what's in the buffer,
 432                          * which may be nothing.  If there is something
 433                          * in the store buffer, we can rotate the buffers.
 434                          */
 435                         if (d->bd_hbuf)
 436                                 /*
 437                                  * We filled up the buffer in between
 438                                  * getting the timeout and arriving
 439                                  * here, so we don't need to rotate.
 440                                  */
 441                                 break;
 442
 443                         if (d->bd_slen == 0) {
 444                                 crit_exit();
 445                                 return(0);
 446                         }
 447                         ROTATE_BUFFERS(d);
 448                         break;
 449                 }
 450         }
 451         /*
 452          * At this point, we know we have something in the hold slot.
 453          */
 454         crit_exit();
 455
 456         /*
 457          * Move data from hold buffer into user space.
 458          * We know the entire buffer is transferred since
 459          * we checked above that the read buffer is bpf_bufsize bytes.
 460          */
 461         error = uiomove(d->bd_hbuf, d->bd_hlen, ap->a_uio);
 462
 463         crit_enter();
 464         d->bd_fbuf = d->bd_hbuf;
 465         d->bd_hbuf = NULL;
 466         d->bd_hlen = 0;
 467         crit_exit();
 468
 469         return(error);
 470 }
 471
 472
 473 /*
 474  * If there are processes sleeping on this descriptor, wake them up.
 475  */
 476 static void
 477 bpf_wakeup(struct bpf_d *d)
 478 {
 479         if (d->bd_state == BPF_WAITING) {
 480                 callout_stop(&d->bd_callout);
 481                 d->bd_state = BPF_IDLE;
 482         }
 483         wakeup(d);
 484         if (d->bd_async && d->bd_sig && d->bd_sigio)
 485                 pgsigio(d->bd_sigio, d->bd_sig, 0);
 486
 487         get_mplock();
 488         selwakeup(&d->bd_sel);
 489         rel_mplock();
 490         /* XXX */
 491         d->bd_sel.si_pid = 0;
 492 }
 493
 494 static void
 495 bpf_timed_out(void *arg)
 496 {
 497         struct bpf_d *d = (struct bpf_d *)arg;
 498
 499         crit_enter();
 500         if (d->bd_state == BPF_WAITING) {
 501                 d->bd_state = BPF_TIMED_OUT;
 502                 if (d->bd_slen != 0)
 503                         bpf_wakeup(d);
 504         }
 505         crit_exit();
 506 }
 507
 508 static void
 509 bpf_output_dispatch(struct netmsg *nmsg)
 510 {
 511         struct netmsg_bpf_output *bmsg = (struct netmsg_bpf_output *)nmsg;
 512         struct ifnet *ifp = bmsg->nm_ifp;
 513         int error;
 514
 515         /*
 516          * The driver frees the mbuf.
 517          */
 518         error = ifp->if_output(ifp, bmsg->nm_mbuf, bmsg->nm_dst, NULL);
 519         lwkt_replymsg(&nmsg->nm_lmsg, error);
 520 }
 521
 522 static int
 523 bpfwrite(struct dev_write_args *ap)
 524 {
 525         cdev_t dev = ap->a_head.a_dev;
 526         struct bpf_d *d = dev->si_drv1;
 527         struct ifnet *ifp;
 528         struct mbuf *m;
 529         int error;
 530         struct sockaddr dst;
 531         int datlen;
 532         struct netmsg_bpf_output bmsg;
 533
 534         if (d->bd_bif == NULL)
 535                 return(ENXIO);
 536
 537         ifp = d->bd_bif->bif_ifp;
 538
 539         if (ap->a_uio->uio_resid == 0)
 540                 return(0);
 541
 542         error = bpf_movein(ap->a_uio, (int)d->bd_bif->bif_dlt, &m,
 543                            &dst, &datlen, d->bd_wfilter);
 544         if (error)
 545                 return(error);
 546
 547         if (datlen > ifp->if_mtu) {
 548                 m_freem(m);
 549                 return(EMSGSIZE);
 550         }
 551
 552         if (d->bd_hdrcmplt)
 553                 dst.sa_family = pseudo_AF_HDRCMPLT;
 554
 555         netmsg_init(&bmsg.nm_netmsg, &curthread->td_msgport, MSGF_MPSAFE,
 556                     bpf_output_dispatch);
 557         bmsg.nm_mbuf = m;
 558         bmsg.nm_ifp = ifp;
 559         bmsg.nm_dst = &dst;
 560
 561         return lwkt_domsg(cpu_portfn(0), &bmsg.nm_netmsg.nm_lmsg, 0);
 562 }
 563
 564 /*
 565  * Reset a descriptor by flushing its packet buffer and clearing the
 566  * receive and drop counts.  Should be called at splimp.
 567  */
 568 static void
 569 bpf_resetd(struct bpf_d *d)
 570 {
 571         if (d->bd_hbuf) {
 572                 /* Free the hold buffer. */
 573                 d->bd_fbuf = d->bd_hbuf;
 574                 d->bd_hbuf = NULL;
 575         }
 576         d->bd_slen = 0;
 577         d->bd_hlen = 0;
 578         d->bd_rcount = 0;
 579         d->bd_dcount = 0;
 580 }
 581
 582 /*
 583  *  FIONREAD            Check for read packet available.
 584  *  SIOCGIFADDR         Get interface address - convenient hook to driver.
 585  *  BIOCGBLEN           Get buffer len [for read()].
 586  *  BIOCSETF            Set ethernet read filter.
 587  *  BIOCSETWF           Set ethernet write filter.
 588  *  BIOCFLUSH           Flush read packet buffer.
 589  *  BIOCPROMISC         Put interface into promiscuous mode.
 590  *  BIOCGDLT            Get link layer type.
 591  *  BIOCGETIF           Get interface name.
 592  *  BIOCSETIF           Set interface.
 593  *  BIOCSRTIMEOUT       Set read timeout.
 594  *  BIOCGRTIMEOUT       Get read timeout.
 595  *  BIOCGSTATS          Get packet stats.
 596  *  BIOCIMMEDIATE       Set immediate mode.
 597  *  BIOCVERSION         Get filter language version.
 598  *  BIOCGHDRCMPLT       Get "header already complete" flag
 599  *  BIOCSHDRCMPLT       Set "header already complete" flag
 600  *  BIOCGSEESENT        Get "see packets sent" flag
 601  *  BIOCSSEESENT        Set "see packets sent" flag
 602  *  BIOCLOCK            Set "locked" flag
 603  */
 604 /* ARGSUSED */
 605 static int
 606 bpfioctl(struct dev_ioctl_args *ap)
 607 {
 608         cdev_t dev = ap->a_head.a_dev;
 609         struct bpf_d *d = dev->si_drv1;
 610         int error = 0;
 611
 612         crit_enter();
 613         if (d->bd_state == BPF_WAITING)
 614                 callout_stop(&d->bd_callout);
 615         d->bd_state = BPF_IDLE;
 616         crit_exit();
 617
 618         if (d->bd_locked == 1) {
 619                 switch (ap->a_cmd) {
 620                 case BIOCGBLEN:
 621                 case BIOCFLUSH:
 622                 case BIOCGDLT:
 623                 case BIOCGDLTLIST:
 624                 case BIOCGETIF:
 625                 case BIOCGRTIMEOUT:
 626                 case BIOCGSTATS:
 627                 case BIOCVERSION:
 628                 case BIOCGRSIG:
 629                 case BIOCGHDRCMPLT:
 630                 case FIONREAD:
 631                 case BIOCLOCK:
 632                 case BIOCSRTIMEOUT:
 633                 case BIOCIMMEDIATE:
 634                 case TIOCGPGRP:
 635                         break;
 636                 default:
 637                         return (EPERM);
 638                 }
 639         }
 640         switch (ap->a_cmd) {
 641         default:
 642                 error = EINVAL;
 643                 break;
 644
 645         /*
 646          * Check for read packet available.
 647          */
 648         case FIONREAD:
 649                 {
 650                         int n;
 651
 652                         crit_enter();
 653                         n = d->bd_slen;
 654                         if (d->bd_hbuf)
 655                                 n += d->bd_hlen;
 656                         crit_exit();
 657
 658                         *(int *)ap->a_data = n;
 659                         break;
 660                 }
 661
 662         case SIOCGIFADDR:
 663                 {
 664                         struct ifnet *ifp;
 665
 666                         if (d->bd_bif == NULL) {
 667                                 error = EINVAL;
 668                         } else {
 669                                 ifp = d->bd_bif->bif_ifp;
 670                                 lwkt_serialize_enter(ifp->if_serializer);
 671                                 error = ifp->if_ioctl(ifp, ap->a_cmd,
 672                                                       ap->a_data, ap->a_cred);
 673                                 lwkt_serialize_exit(ifp->if_serializer);
 674                         }
 675                         break;
 676                 }
 677
 678         /*
 679          * Get buffer len [for read()].
 680          */
 681         case BIOCGBLEN:
 682                 *(u_int *)ap->a_data = d->bd_bufsize;
 683                 break;
 684
 685         /*
 686          * Set buffer length.
 687          */
 688         case BIOCSBLEN:
 689                 if (d->bd_bif != NULL) {
 690                         error = EINVAL;
 691                 } else {
 692                         u_int size = *(u_int *)ap->a_data;
 693
 694                         if (size > bpf_maxbufsize)
 695                                 *(u_int *)ap->a_data = size = bpf_maxbufsize;
 696                         else if (size < BPF_MINBUFSIZE)
 697                                 *(u_int *)ap->a_data = size = BPF_MINBUFSIZE;
 698                         d->bd_bufsize = size;
 699                 }
 700                 break;
 701
 702         /*
 703          * Set link layer read filter.
 704          */
 705         case BIOCSETF:
 706         case BIOCSETWF:
 707                 error = bpf_setf(d, (struct bpf_program *)ap->a_data,
 708                         ap->a_cmd);
 709                 break;
 710
 711         /*
 712          * Flush read packet buffer.
 713          */
 714         case BIOCFLUSH:
 715                 crit_enter();
 716                 bpf_resetd(d);
 717                 crit_exit();
 718                 break;
 719
 720         /*
 721          * Put interface into promiscuous mode.
 722          */
 723         case BIOCPROMISC:
 724                 if (d->bd_bif == NULL) {
 725                         /*
 726                          * No interface attached yet.
 727                          */
 728                         error = EINVAL;
 729                         break;
 730                 }
 731                 crit_enter();
 732                 if (d->bd_promisc == 0) {
 733                         error = ifpromisc(d->bd_bif->bif_ifp, 1);
 734                         if (error == 0)
 735                                 d->bd_promisc = 1;
 736                 }
 737                 crit_exit();
 738                 break;
 739
 740         /*
 741          * Get device parameters.
 742          */
 743         case BIOCGDLT:
 744                 if (d->bd_bif == NULL)
 745                         error = EINVAL;
 746                 else
 747                         *(u_int *)ap->a_data = d->bd_bif->bif_dlt;
 748                 break;
 749
 750         /*
 751          * Get a list of supported data link types.
 752          */
 753         case BIOCGDLTLIST:
 754                 if (d->bd_bif == NULL) {
 755                         error = EINVAL;
 756                 } else {
 757                         error = bpf_getdltlist(d,
 758                                 (struct bpf_dltlist *)ap->a_data);
 759                 }
 760                 break;
 761
 762         /*
 763          * Set data link type.
 764          */
 765         case BIOCSDLT:
 766                 if (d->bd_bif == NULL)
 767                         error = EINVAL;
 768                 else
 769                         error = bpf_setdlt(d, *(u_int *)ap->a_data);
 770                 break;
 771
 772         /*
 773          * Get interface name.
 774          */
 775         case BIOCGETIF:
 776                 if (d->bd_bif == NULL) {
 777                         error = EINVAL;
 778                 } else {
 779                         struct ifnet *const ifp = d->bd_bif->bif_ifp;
 780                         struct ifreq *const ifr = (struct ifreq *)ap->a_data;
 781
 782                         strlcpy(ifr->ifr_name, ifp->if_xname,
 783                                 sizeof ifr->ifr_name);
 784                 }
 785                 break;
 786
 787         /*
 788          * Set interface.
 789          */
 790         case BIOCSETIF:
 791                 error = bpf_setif(d, (struct ifreq *)ap->a_data);
 792                 break;
 793
 794         /*
 795          * Set read timeout.
 796          */
 797         case BIOCSRTIMEOUT:
 798                 {
 799                         struct timeval *tv = (struct timeval *)ap->a_data;
 800
 801                         /*
 802                          * Subtract 1 tick from tvtohz() since this isn't
 803                          * a one-shot timer.
 804                          */
 805                         if ((error = itimerfix(tv)) == 0)
 806                                 d->bd_rtout = tvtohz_low(tv);
 807                         break;
 808                 }
 809
 810         /*
 811          * Get read timeout.
 812          */
 813         case BIOCGRTIMEOUT:
 814                 {
 815                         struct timeval *tv = (struct timeval *)ap->a_data;
 816
 817                         tv->tv_sec = d->bd_rtout / hz;
 818                         tv->tv_usec = (d->bd_rtout % hz) * tick;
 819                         break;
 820                 }
 821
 822         /*
 823          * Get packet stats.
 824          */
 825         case BIOCGSTATS:
 826                 {
 827                         struct bpf_stat *bs = (struct bpf_stat *)ap->a_data;
 828
 829                         bs->bs_recv = d->bd_rcount;
 830                         bs->bs_drop = d->bd_dcount;
 831                         break;
 832                 }
 833
 834         /*
 835          * Set immediate mode.
 836          */
 837         case BIOCIMMEDIATE:
 838                 d->bd_immediate = *(u_int *)ap->a_data;
 839                 break;
 840
 841         case BIOCVERSION:
 842                 {
 843                         struct bpf_version *bv = (struct bpf_version *)ap->a_data;
 844
 845                         bv->bv_major = BPF_MAJOR_VERSION;
 846                         bv->bv_minor = BPF_MINOR_VERSION;
 847                         break;
 848                 }
 849
 850         /*
 851          * Get "header already complete" flag
 852          */
 853         case BIOCGHDRCMPLT:
 854                 *(u_int *)ap->a_data = d->bd_hdrcmplt;
 855                 break;
 856
 857         /*
 858          * Set "header already complete" flag
 859          */
 860         case BIOCSHDRCMPLT:
 861                 d->bd_hdrcmplt = *(u_int *)ap->a_data ? 1 : 0;
 862                 break;
 863
 864         /*
 865          * Get "see sent packets" flag
 866          */
 867         case BIOCGSEESENT:
 868                 *(u_int *)ap->a_data = d->bd_seesent;
 869                 break;
 870
 871         /*
 872          * Set "see sent packets" flag
 873          */
 874         case BIOCSSEESENT:
 875                 d->bd_seesent = *(u_int *)ap->a_data;
 876                 break;
 877
 878         case FIOASYNC:          /* Send signal on receive packets */
 879                 d->bd_async = *(int *)ap->a_data;
 880                 break;
 881
 882         case FIOSETOWN:
 883                 error = fsetown(*(int *)ap->a_data, &d->bd_sigio);
 884                 break;
 885
 886         case FIOGETOWN:
 887                 *(int *)ap->a_data = fgetown(d->bd_sigio);
 888                 break;
 889
 890         /* This is deprecated, FIOSETOWN should be used instead. */
 891         case TIOCSPGRP:
 892                 error = fsetown(-(*(int *)ap->a_data), &d->bd_sigio);
 893                 break;
 894
 895         /* This is deprecated, FIOGETOWN should be used instead. */
 896         case TIOCGPGRP:
 897                 *(int *)ap->a_data = -fgetown(d->bd_sigio);
 898                 break;
 899
 900         case BIOCSRSIG:         /* Set receive signal */
 901                 {
 902                         u_int sig;
 903
 904                         sig = *(u_int *)ap->a_data;
 905
 906                         if (sig >= NSIG)
 907                                 error = EINVAL;
 908                         else
 909                                 d->bd_sig = sig;
 910                         break;
 911                 }
 912         case BIOCGRSIG:
 913                 *(u_int *)ap->a_data = d->bd_sig;
 914                 break;
 915         case BIOCLOCK:
 916                 d->bd_locked = 1;
 917                 break;
 918         }
 919         return(error);
 920 }
 921
 922 /*
 923  * Set d's packet filter program to fp.  If this file already has a filter,
 924  * free it and replace it.  Returns EINVAL for bogus requests.
 925  */
 926 static int
 927 bpf_setf(struct bpf_d *d, struct bpf_program *fp, u_long cmd)
 928 {
 929         struct bpf_insn *fcode, *old;
 930         u_int wfilter, flen, size;
 931
 932         if (cmd == BIOCSETWF) {
 933                 old = d->bd_wfilter;
 934                 wfilter = 1;
 935         } else {
 936                 wfilter = 0;
 937                 old = d->bd_rfilter;
 938         }
 939         if (fp->bf_insns == NULL) {
 940                 if (fp->bf_len != 0)
 941                         return(EINVAL);
 942                 crit_enter();
 943                 if (wfilter)
 944                         d->bd_wfilter = NULL;
 945                 else
 946                         d->bd_rfilter = NULL;
 947                 bpf_resetd(d);
 948                 crit_exit();
 949                 if (old != NULL)
 950                         kfree(old, M_BPF);
 951                 return(0);
 952         }
 953         flen = fp->bf_len;
 954         if (flen > BPF_MAXINSNS)
 955                 return(EINVAL);
 956
 957         size = flen * sizeof *fp->bf_insns;
 958         fcode = (struct bpf_insn *)kmalloc(size, M_BPF, M_WAITOK);
 959         if (copyin(fp->bf_insns, fcode, size) == 0 &&
 960             bpf_validate(fcode, (int)flen)) {
 961                 crit_enter();
 962                 if (wfilter)
 963                         d->bd_wfilter = fcode;
 964                 else
 965                         d->bd_rfilter = fcode;
 966                 bpf_resetd(d);
 967                 crit_exit();
 968                 if (old != NULL)
 969                         kfree(old, M_BPF);
 970
 971                 return(0);
 972         }
 973         kfree(fcode, M_BPF);
 974         return(EINVAL);
 975 }
 976
 977 /*
 978  * Detach a file from its current interface (if attached at all) and attach
 979  * to the interface indicated by the name stored in ifr.
 980  * Return an errno or 0.
 981  */
 982 static int
 983 bpf_setif(struct bpf_d *d, struct ifreq *ifr)
 984 {
 985         struct bpf_if *bp;
 986         int error;
 987         struct ifnet *theywant;
 988
 989         theywant = ifunit(ifr->ifr_name);
 990         if (theywant == NULL)
 991                 return(ENXIO);
 992
 993         /*
 994          * Look through attached interfaces for the named one.
 995          */
 996         for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
 997                 struct ifnet *ifp = bp->bif_ifp;
 998
 999                 if (ifp == NULL || ifp != theywant)
1000                         continue;
1001                 /* skip additional entry */
1002                 if (bp->bif_driverp != &ifp->if_bpf)
1003                         continue;
1004                 /*
1005                  * We found the requested interface.
1006                  * If it's not up, return an error.
1007                  * Allocate the packet buffers if we need to.
1008                  * If we're already attached to requested interface,
1009                  * just flush the buffer.
1010                  */
1011                 if (!(ifp->if_flags & IFF_UP))
1012                         return(ENETDOWN);
1013
1014                 if (d->bd_sbuf == NULL) {
1015                         error = bpf_allocbufs(d);
1016                         if (error != 0)
1017                                 return(error);
1018                 }
1019                 crit_enter();
1020                 if (bp != d->bd_bif) {
1021                         if (d->bd_bif != NULL) {
1022                                 /*
1023                                  * Detach if attached to something else.
1024                                  */
1025                                 bpf_detachd(d);
1026                         }
1027
1028                         bpf_attachd(d, bp);
1029                 }
1030                 bpf_resetd(d);
1031                 crit_exit();
1032                 return(0);
1033         }
1034
1035         /* Not found. */
1036         return(ENXIO);
1037 }
1038
1039 /*
1040  * Support for select() and poll() system calls
1041  *
1042  * Return true iff the specific operation will not block indefinitely.
1043  * Otherwise, return false but make a note that a selwakeup() must be done.
1044  */
1045 static int
1046 bpfpoll(struct dev_poll_args *ap)
1047 {
1048         cdev_t dev = ap->a_head.a_dev;
1049         struct bpf_d *d;
1050         int revents;
1051
1052         d = dev->si_drv1;
1053         if (d->bd_bif == NULL)
1054                 return(ENXIO);
1055
1056         revents = ap->a_events & (POLLOUT | POLLWRNORM);
1057         crit_enter();
1058         if (ap->a_events & (POLLIN | POLLRDNORM)) {
1059                 /*
1060                  * An imitation of the FIONREAD ioctl code.
1061                  * XXX not quite.  An exact imitation:
1062                  *      if (d->b_slen != 0 ||
1063                  *          (d->bd_hbuf != NULL && d->bd_hlen != 0)
1064                  */
1065                 if (d->bd_hlen != 0 ||
1066                     ((d->bd_immediate || d->bd_state == BPF_TIMED_OUT) &&
1067                     d->bd_slen != 0)) {
1068                         revents |= ap->a_events & (POLLIN | POLLRDNORM);
1069                 } else {
1070                         selrecord(curthread, &d->bd_sel);
1071                         /* Start the read timeout if necessary. */
1072                         if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) {
1073                                 callout_reset(&d->bd_callout, d->bd_rtout,
1074                                     bpf_timed_out, d);
1075                                 d->bd_state = BPF_WAITING;
1076                         }
1077                 }
1078         }
1079         crit_exit();
1080         ap->a_events = revents;
1081         return(0);
1082 }
1083
1084 /*
1085  * Process the packet pkt of length pktlen.  The packet is parsed
1086  * by each listener's filter, and if accepted, stashed into the
1087  * corresponding buffer.
1088  */
1089 void
1090 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
1091 {
1092         struct bpf_d *d;
1093         struct timeval tv;
1094         int gottime = 0;
1095         u_int slen;
1096
1097         get_mplock();
1098
1099         /* Re-check */
1100         if (bp == NULL) {
1101                 rel_mplock();
1102                 return;
1103         }
1104
1105         /*
1106          * Note that the ipl does not have to be raised at this point.
1107          * The only problem that could arise here is that if two different
1108          * interfaces shared any data.  This is not the case.
1109          */
1110         SLIST_FOREACH(d, &bp->bif_dlist, bd_next) {
1111                 ++d->bd_rcount;
1112                 slen = bpf_filter(d->bd_rfilter, pkt, pktlen, pktlen);
1113                 if (slen != 0) {
1114                         if (!gottime) {
1115                                 microtime(&tv);
1116                                 gottime = 1;
1117                         }
1118                         catchpacket(d, pkt, pktlen, slen, ovbcopy, &tv);
1119                 }
1120         }
1121
1122         rel_mplock();
1123 }
1124
1125 /*
1126  * Copy data from an mbuf chain into a buffer.  This code is derived
1127  * from m_copydata in sys/uipc_mbuf.c.
1128  */
1129 static void
1130 bpf_mcopy(const void *src_arg, void *dst_arg, size_t len)
1131 {
1132         const struct mbuf *m;
1133         u_int count;
1134         u_char *dst;
1135
1136         m = src_arg;
1137         dst = dst_arg;
1138         while (len > 0) {
1139                 if (m == NULL)
1140                         panic("bpf_mcopy");
1141                 count = min(m->m_len, len);
1142                 bcopy(mtod(m, void *), dst, count);
1143                 m = m->m_next;
1144                 dst += count;
1145                 len -= count;
1146         }
1147 }
1148
1149 /*
1150  * Process the packet in the mbuf chain m.  The packet is parsed by each
1151  * listener's filter, and if accepted, stashed into the corresponding
1152  * buffer.
1153  */
1154 void
1155 bpf_mtap(struct bpf_if *bp, struct mbuf *m)
1156 {
1157         struct bpf_d *d;
1158         u_int pktlen, slen;
1159         struct timeval tv;
1160         int gottime = 0;
1161
1162         get_mplock();
1163
1164         /* Re-check */
1165         if (bp == NULL) {
1166                 rel_mplock();
1167                 return;
1168         }
1169
1170         /* Don't compute pktlen, if no descriptor is attached. */
1171         if (SLIST_EMPTY(&bp->bif_dlist)) {
1172                 rel_mplock();
1173                 return;
1174         }
1175
1176         pktlen = m_lengthm(m, NULL);
1177
1178         SLIST_FOREACH(d, &bp->bif_dlist, bd_next) {
1179                 if (!d->bd_seesent && (m->m_pkthdr.rcvif == NULL))
1180                         continue;
1181                 ++d->bd_rcount;
1182                 slen = bpf_filter(d->bd_rfilter, (u_char *)m, pktlen, 0);
1183                 if (slen != 0) {
1184                         if (!gottime) {
1185                                 microtime(&tv);
1186                                 gottime = 1;
1187                         }
1188                         catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy,
1189                                     &tv);
1190                 }
1191         }
1192
1193         rel_mplock();
1194 }
1195
1196 void
1197 bpf_mtap_family(struct bpf_if *bp, struct mbuf *m, sa_family_t family)
1198 {
1199         u_int family4;
1200
1201         KKASSERT(family != AF_UNSPEC);
1202
1203         family4 = (u_int)family;
1204         bpf_ptap(bp, m, &family4, sizeof(family4));
1205 }
1206
1207 /*
1208  * Process the packet in the mbuf chain m with the header in m prepended.
1209  * The packet is parsed by each listener's filter, and if accepted,
1210  * stashed into the corresponding buffer.
1211  */
1212 void
1213 bpf_ptap(struct bpf_if *bp, struct mbuf *m, const void *data, u_int dlen)
1214 {
1215         struct mbuf mb;
1216
1217         /*
1218          * Craft on-stack mbuf suitable for passing to bpf_mtap.
1219          * Note that we cut corners here; we only setup what's
1220          * absolutely needed--this mbuf should never go anywhere else.
1221          */
1222         mb.m_next = m;
1223         mb.m_data = __DECONST(void *, data); /* LINTED */
1224         mb.m_len = dlen;
1225         mb.m_pkthdr.rcvif = m->m_pkthdr.rcvif;
1226
1227         bpf_mtap(bp, &mb);
1228 }
1229
1230 /*
1231  * Move the packet data from interface memory (pkt) into the
1232  * store buffer.  Return 1 if it's time to wakeup a listener (buffer full),
1233  * otherwise 0.  "copy" is the routine called to do the actual data
1234  * transfer.  bcopy is passed in to copy contiguous chunks, while
1235  * bpf_mcopy is passed in to copy mbuf chains.  In the latter case,
1236  * pkt is really an mbuf.
1237  */
1238 static void
1239 catchpacket(struct bpf_d *d, u_char *pkt, u_int pktlen, u_int snaplen,
1240             void (*cpfn)(const void *, void *, size_t),
1241             const struct timeval *tv)
1242 {
1243         struct bpf_hdr *hp;
1244         int totlen, curlen;
1245         int hdrlen = d->bd_bif->bif_hdrlen;
1246         /*
1247          * Figure out how many bytes to move.  If the packet is
1248          * greater or equal to the snapshot length, transfer that
1249          * much.  Otherwise, transfer the whole packet (unless
1250          * we hit the buffer size limit).
1251          */
1252         totlen = hdrlen + min(snaplen, pktlen);
1253         if (totlen > d->bd_bufsize)
1254                 totlen = d->bd_bufsize;
1255
1256         /*
1257          * Round up the end of the previous packet to the next longword.
1258          */
1259         curlen = BPF_WORDALIGN(d->bd_slen);
1260         if (curlen + totlen > d->bd_bufsize) {
1261                 /*
1262                  * This packet will overflow the storage buffer.
1263                  * Rotate the buffers if we can, then wakeup any
1264                  * pending reads.
1265                  */
1266                 if (d->bd_fbuf == NULL) {
1267                         /*
1268                          * We haven't completed the previous read yet,
1269                          * so drop the packet.
1270                          */
1271                         ++d->bd_dcount;
1272                         return;
1273                 }
1274                 ROTATE_BUFFERS(d);
1275                 bpf_wakeup(d);
1276                 curlen = 0;
1277         } else if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT) {
1278                 /*
1279                  * Immediate mode is set, or the read timeout has
1280                  * already expired during a select call.  A packet
1281                  * arrived, so the reader should be woken up.
1282                  */
1283                 bpf_wakeup(d);
1284         }
1285
1286         /*
1287          * Append the bpf header.
1288          */
1289         hp = (struct bpf_hdr *)(d->bd_sbuf + curlen);
1290         hp->bh_tstamp = *tv;
1291         hp->bh_datalen = pktlen;
1292         hp->bh_hdrlen = hdrlen;
1293         /*
1294          * Copy the packet data into the store buffer and update its length.
1295          */
1296         (*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen));
1297         d->bd_slen = curlen + totlen;
1298 }
1299
1300 /*
1301  * Initialize all nonzero fields of a descriptor.
1302  */
1303 static int
1304 bpf_allocbufs(struct bpf_d *d)
1305 {
1306         d->bd_fbuf = kmalloc(d->bd_bufsize, M_BPF, M_WAITOK);
1307         d->bd_sbuf = kmalloc(d->bd_bufsize, M_BPF, M_WAITOK);
1308         d->bd_slen = 0;
1309         d->bd_hlen = 0;
1310         return(0);
1311 }
1312
1313 /*
1314  * Free buffers and packet filter program currently in use by a descriptor.
1315  * Called on close.
1316  */
1317 static void
1318 bpf_freed(struct bpf_d *d)
1319 {
1320         /*
1321          * We don't need to lock out interrupts since this descriptor has
1322          * been detached from its interface and it yet hasn't been marked
1323          * free.
1324          */
1325         if (d->bd_sbuf != NULL) {
1326                 kfree(d->bd_sbuf, M_BPF);
1327                 if (d->bd_hbuf != NULL)
1328                         kfree(d->bd_hbuf, M_BPF);
1329                 if (d->bd_fbuf != NULL)
1330                         kfree(d->bd_fbuf, M_BPF);
1331         }
1332         if (d->bd_rfilter)
1333                 kfree(d->bd_rfilter, M_BPF);
1334         if (d->bd_wfilter)
1335                 kfree(d->bd_wfilter, M_BPF);
1336 }
1337
1338 /*
1339  * Attach an interface to bpf.  ifp is a pointer to the structure
1340  * defining the interface to be attached, dlt is the link layer type,
1341  * and hdrlen is the fixed size of the link header (variable length
1342  * headers are not yet supported).
1343  */
1344 void
1345 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
1346 {
1347         bpfattach_dlt(ifp, dlt, hdrlen, &ifp->if_bpf);
1348 }
1349
1350 void
1351 bpfattach_dlt(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp)
1352 {
1353         struct bpf_if *bp;
1354
1355         bp = kmalloc(sizeof *bp, M_BPF, M_WAITOK | M_ZERO);
1356
1357         SLIST_INIT(&bp->bif_dlist);
1358         bp->bif_ifp = ifp;
1359         bp->bif_dlt = dlt;
1360         bp->bif_driverp = driverp;
1361         *bp->bif_driverp = NULL;
1362
1363         bp->bif_next = bpf_iflist;
1364         bpf_iflist = bp;
1365
1366         /*
1367          * Compute the length of the bpf header.  This is not necessarily
1368          * equal to SIZEOF_BPF_HDR because we want to insert spacing such
1369          * that the network layer header begins on a longword boundary (for
1370          * performance reasons and to alleviate alignment restrictions).
1371          */
1372         bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen;
1373
1374         if (bootverbose)
1375                 if_printf(ifp, "bpf attached\n");
1376 }
1377
1378 /*
1379  * Detach bpf from an interface.  This involves detaching each descriptor
1380  * associated with the interface, and leaving bd_bif NULL.  Notify each
1381  * descriptor as it's detached so that any sleepers wake up and get
1382  * ENXIO.
1383  */
1384 void
1385 bpfdetach(struct ifnet *ifp)
1386 {
1387         struct bpf_if *bp, *bp_prev;
1388         struct bpf_d *d;
1389
1390         crit_enter();
1391
1392         /* Locate BPF interface information */
1393         bp_prev = NULL;
1394         for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1395                 if (ifp == bp->bif_ifp)
1396                         break;
1397                 bp_prev = bp;
1398         }
1399
1400         /* Interface wasn't attached */
1401         if (bp->bif_ifp == NULL) {
1402                 crit_exit();
1403                 kprintf("bpfdetach: %s was not attached\n", ifp->if_xname);
1404                 return;
1405         }
1406
1407         while ((d = SLIST_FIRST(&bp->bif_dlist)) != NULL) {
1408                 bpf_detachd(d);
1409                 bpf_wakeup(d);
1410         }
1411
1412         if (bp_prev != NULL)
1413                 bp_prev->bif_next = bp->bif_next;
1414         else
1415                 bpf_iflist = bp->bif_next;
1416
1417         kfree(bp, M_BPF);
1418
1419         crit_exit();
1420 }
1421
1422 /*
1423  * Get a list of available data link type of the interface.
1424  */
1425 static int
1426 bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl)
1427 {
1428         int n, error;
1429         struct ifnet *ifp;
1430         struct bpf_if *bp;
1431
1432         ifp = d->bd_bif->bif_ifp;
1433         n = 0;
1434         error = 0;
1435         for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1436                 if (bp->bif_ifp != ifp)
1437                         continue;
1438                 if (bfl->bfl_list != NULL) {
1439                         if (n >= bfl->bfl_len) {
1440                                 return (ENOMEM);
1441                         }
1442                         error = copyout(&bp->bif_dlt,
1443                             bfl->bfl_list + n, sizeof(u_int));
1444                 }
1445                 n++;
1446         }
1447         bfl->bfl_len = n;
1448         return(error);
1449 }
1450
1451 /*
1452  * Set the data link type of a BPF instance.
1453  */
1454 static int
1455 bpf_setdlt(struct bpf_d *d, u_int dlt)
1456 {
1457         int error, opromisc;
1458         struct ifnet *ifp;
1459         struct bpf_if *bp;
1460
1461         if (d->bd_bif->bif_dlt == dlt)
1462                 return (0);
1463         ifp = d->bd_bif->bif_ifp;
1464         for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1465                 if (bp->bif_ifp == ifp && bp->bif_dlt == dlt)
1466                         break;
1467         }
1468         if (bp != NULL) {
1469                 opromisc = d->bd_promisc;
1470                 crit_enter();
1471                 bpf_detachd(d);
1472                 bpf_attachd(d, bp);
1473                 bpf_resetd(d);
1474                 if (opromisc) {
1475                         error = ifpromisc(bp->bif_ifp, 1);
1476                         if (error) {
1477                                 if_printf(bp->bif_ifp,
1478                                         "bpf_setdlt: ifpromisc failed (%d)\n",
1479                                         error);
1480                         } else {
1481                                 d->bd_promisc = 1;
1482                         }
1483                 }
1484                 crit_exit();
1485         }
1486         return(bp == NULL ? EINVAL : 0);
1487 }
1488
1489 static void
1490 bpf_drvinit(void *unused)
1491 {
1492         dev_ops_add(&bpf_ops, 0, 0);
1493 }
1494
1495 SYSINIT(bpfdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,bpf_drvinit,NULL)
1496
1497 #else /* !BPF */
1498 /*
1499  * NOP stubs to allow bpf-using drivers to load and function.
1500  *
1501  * A 'better' implementation would allow the core bpf functionality
1502  * to be loaded at runtime.
1503  */
1504
1505 void
1506 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
1507 {
1508 }
1509
1510 void
1511 bpf_mtap(struct bpf_if *bp, struct mbuf *m)
1512 {
1513 }
1514
1515 void
1516 bpf_ptap(struct bpf_if *bp, struct mbuf *m, const void *data, u_int dlen)
1517 {
1518 }
1519
1520 void
1521 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
1522 {
1523 }
1524
1525 void
1526 bpfattach_dlt(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp)
1527 {
1528 }
1529
1530 void
1531 bpfdetach(struct ifnet *ifp)
1532 {
1533 }
1534
1535 u_int
1536 bpf_filter(const struct bpf_insn *pc, u_char *p, u_int wirelen, u_int buflen)
1537 {
1538         return -1;      /* "no filter" behaviour */
1539 }
1540
1541 #endif /* !BPF */