xnu-792.12.6.tar.gz

[apple/xnu.git] / bsd / net / bpf.c

/*
 * Copyright (c) 2006 Apple Computer, Inc. All Rights Reserved.
 * 
 * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code 
 * as defined in and that are subject to the Apple Public Source License 
 * Version 2.0 (the 'License'). You may not use this file except in 
 * compliance with the License.  The rights granted to you under the 
 * License may not be used to create, or enable the creation or 
 * redistribution of, unlawful or unlicensed copies of an Apple operating 
 * system, or to circumvent, violate, or enable the circumvention or 
 * violation of, any terms of an Apple operating system software license 
 * agreement.
 *
 * Please obtain a copy of the License at 
 * http://www.opensource.apple.com/apsl/ and read it before using this 
 * file.
 *
 * The Original Code and all software distributed under the License are 
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
 * Please see the License for the specific language governing rights and 
 * limitations under the License.
 *
 * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
 */
/*
 * Copyright (c) 1990, 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from the Stanford/CMU enet packet filter,
 * (net/enet.c) distributed as part of 4.3BSD, and code contributed
 * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence
 * Berkeley Laboratory.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)bpf.c       8.2 (Berkeley) 3/28/94
 *
 * $FreeBSD: src/sys/net/bpf.c,v 1.59.2.5 2001/01/05 04:49:09 jdp Exp $
 */

#include "bpf.h"

#ifndef __GNUC__
#define inline
#else
#define inline __inline
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/time.h>
#include <sys/proc.h>
#include <sys/signalvar.h>
#include <sys/filio.h>
#include <sys/sockio.h>
#include <sys/ttycom.h>
#include <sys/filedesc.h>
#include <sys/uio_internal.h>

#if defined(sparc) && BSD < 199103
#include <sys/stream.h>
#endif
#include <sys/poll.h>

#include <sys/socket.h>
#include <sys/vnode.h>

#include <net/if.h>
#include <net/bpf.h>
#include <net/bpfdesc.h>

#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <net/firewire.h>

#include <machine/spl.h>
#include <miscfs/devfs/devfs.h>
#include <net/dlil.h>

#include <kern/locks.h>

extern int tvtohz(struct timeval *);

#if NBPFILTER > 0

/*
 * Older BSDs don't have kernel malloc.
 */
#if BSD < 199103
extern bcopy();
static caddr_t bpf_alloc();
#include <net/bpf_compat.h>
#define BPF_BUFSIZE (MCLBYTES-8)
#define UIOMOVE(cp, len, code, uio) uiomove(cp, len, code, uio)
#else
#define BPF_BUFSIZE 4096
#define UIOMOVE(cp, len, code, uio) uiomove(cp, len, uio)
#endif


#define PRINET  26                      /* interruptible */

/*
 * The default read buffer size is patchable.
 */
static unsigned int bpf_bufsize = BPF_BUFSIZE;
SYSCTL_INT(_debug, OID_AUTO, bpf_bufsize, CTLFLAG_RW, 
        &bpf_bufsize, 0, "");
static unsigned int bpf_maxbufsize = BPF_MAXBUFSIZE;
SYSCTL_INT(_debug, OID_AUTO, bpf_maxbufsize, CTLFLAG_RW, 
        &bpf_maxbufsize, 0, "");
static unsigned int bpf_maxdevices = 256;
SYSCTL_UINT(_debug, OID_AUTO, bpf_maxdevices, CTLFLAG_RW, 
        &bpf_maxdevices, 0, "");

/*
 *  bpf_iflist is the list of interfaces; each corresponds to an ifnet
 *  bpf_dtab holds pointer to the descriptors, indexed by minor device #
 */
static struct bpf_if    *bpf_iflist;
#ifdef __APPLE__
/*
 * BSD now stores the bpf_d in the dev_t which is a struct
 * on their system. Our dev_t is an int, so we still store
 * the bpf_d in a separate table indexed by minor device #.
 *
 * The value stored in bpf_dtab[n] represent three states:
 *  0: device not opened
 *  1: device opening or closing
 *  other: device <n> opened with pointer to storage
 */
static struct bpf_d     **bpf_dtab = NULL;
static unsigned int bpf_dtab_size = 0;
static unsigned int     nbpfilter = 0;

static lck_mtx_t                *bpf_mlock;
static lck_grp_t                *bpf_mlock_grp;
static lck_grp_attr_t   *bpf_mlock_grp_attr;
static lck_attr_t               *bpf_mlock_attr;

/*
 * Mark a descriptor free by making it point to itself.
 * This is probably cheaper than marking with a constant since
 * the address should be in a register anyway.
 */
#endif /* __APPLE__ */

static int      bpf_allocbufs(struct bpf_d *);
static void     bpf_attachd(struct bpf_d *d, struct bpf_if *bp);
static void     bpf_detachd(struct bpf_d *d);
static void     bpf_freed(struct bpf_d *);
static void     bpf_mcopy(const void *, void *, size_t);
static int      bpf_movein(struct uio *, int,
                    struct mbuf **, struct sockaddr *, int *);
static int      bpf_setif(struct bpf_d *, struct ifreq *);
static void bpf_wakeup(struct bpf_d *);
static void     catchpacket(struct bpf_d *, u_char *, u_int,
                    u_int, void (*)(const void *, void *, size_t));
static void     reset_d(struct bpf_d *);
static int bpf_setf(struct bpf_d *, struct user_bpf_program *);

/*static  void *bpf_devfs_token[MAXBPFILTER];*/

static  int bpf_devsw_installed;

void bpf_init(void *unused);
int bpf_tap_callback(struct ifnet *ifp, struct mbuf *m);

/*
 * Darwin differs from BSD here, the following are static
 * on BSD and not static on Darwin.
 */
        d_open_t        bpfopen;
        d_close_t       bpfclose;
        d_read_t        bpfread;
        d_write_t       bpfwrite;
         ioctl_fcn_t    bpfioctl;
        select_fcn_t    bpfpoll;


/* Darwin's cdevsw struct differs slightly from BSDs */
#define CDEV_MAJOR 23
static struct cdevsw bpf_cdevsw = {
        /* open */      bpfopen,
        /* close */     bpfclose,
        /* read */      bpfread,
        /* write */     bpfwrite,
        /* ioctl */     bpfioctl,
        /* stop */              eno_stop,
        /* reset */             eno_reset,
        /* tty */               NULL,
        /* select */    bpfpoll,
        /* mmap */              eno_mmap,
        /* strategy*/   eno_strat,
        /* getc */              eno_getc,
        /* putc */              eno_putc,
        /* type */              0
};

#define SOCKADDR_HDR_LEN           offsetof(struct sockaddr, sa_data)

static int
bpf_movein(struct uio *uio, int linktype, struct mbuf **mp, struct sockaddr *sockp, int *datlen)
{
        struct mbuf *m;
        int error;
        int len;
        int hlen;

        if (sockp) {
                /*
                 * Build a sockaddr based on the data link layer type.
                 * We do this at this level because the ethernet header
                 * is copied directly into the data field of the sockaddr.
                 * In the case of SLIP, there is no header and the packet
                 * is forwarded as is.
                 * Also, we are careful to leave room at the front of the mbuf
                 * for the link level header.
                 */
                switch (linktype) {
        
                case DLT_SLIP:
                        sockp->sa_family = AF_INET;
                        hlen = 0;
                        break;
        
                case DLT_EN10MB:
                        sockp->sa_family = AF_UNSPEC;
                        /* XXX Would MAXLINKHDR be better? */
                        hlen = sizeof(struct ether_header);
                        break;
        
                case DLT_FDDI:
        #if defined(__FreeBSD__) || defined(__bsdi__)
                        sockp->sa_family = AF_IMPLINK;
                        hlen = 0;
        #else
                        sockp->sa_family = AF_UNSPEC;
                        /* XXX 4(FORMAC)+6(dst)+6(src)+3(LLC)+5(SNAP) */
                        hlen = 24;
        #endif
                        break;
        
                case DLT_RAW:
                case DLT_NULL:
                        sockp->sa_family = AF_UNSPEC;
                        hlen = 0;
                        break;
        
        #ifdef __FreeBSD__
                case DLT_ATM_RFC1483:
                        /*
                         * en atm driver requires 4-byte atm pseudo header.
                         * though it isn't standard, vpi:vci needs to be
                         * specified anyway.
                         */
                        sockp->sa_family = AF_UNSPEC;
                        hlen = 12;      /* XXX 4(ATM_PH) + 3(LLC) + 5(SNAP) */
                        break;
        #endif
                case DLT_PPP:
                        sockp->sa_family = AF_UNSPEC;
                        hlen = 4;       /* This should match PPP_HDRLEN */
                        break;
        
                case DLT_APPLE_IP_OVER_IEEE1394:
                        sockp->sa_family = AF_UNSPEC;
                        hlen = sizeof(struct firewire_header);
                        break;
        
                default:
                        return (EIO);
                }
                if ((hlen + SOCKADDR_HDR_LEN) > sockp->sa_len) {
                        return (EIO);
                }
        }
        else {
                hlen = 0;
        }
        
        // LP64todo - fix this!
        len = uio_resid(uio);
        *datlen = len - hlen;
        if ((unsigned)len > MCLBYTES)
                return (EIO);

        MGETHDR(m, M_WAIT, MT_DATA);
        if (m == 0)
                return (ENOBUFS);
        if ((unsigned)len > MHLEN) {
#if BSD >= 199103
                MCLGET(m, M_WAIT);
                if ((m->m_flags & M_EXT) == 0) {
#else
                MCLGET(m);
                if (m->m_len != MCLBYTES) {
#endif
                        error = ENOBUFS;
                        goto bad;
                }
        }
        m->m_pkthdr.len = m->m_len = len;
        m->m_pkthdr.rcvif = NULL;
        *mp = m;
        /*
         * Make room for link header.
         */
        if (hlen != 0) {
                m->m_pkthdr.len -= hlen;
                m->m_len -= hlen;
#if BSD >= 199103
                m->m_data += hlen; /* XXX */
#else
                m->m_off += hlen;
#endif
                error = UIOMOVE((caddr_t)sockp->sa_data, hlen, UIO_WRITE, uio);
                if (error)
                        goto bad;
        }
        error = UIOMOVE(mtod(m, caddr_t), len - hlen, UIO_WRITE, uio);
        if (!error)
                return (0);
 bad:
        m_freem(m);
        return (error);
}

#ifdef __APPLE__
/* Callback registered with Ethernet driver. */
int bpf_tap_callback(struct ifnet *ifp, struct mbuf *m)
{
    /*
     * Do nothing if the BPF tap has been turned off.
     * This is to protect from a potential race where this
     * call blocks on the lock. And in the meantime
     * BPF is turned off, which will clear if_bpf.
     */
    if (ifp->if_bpf)
        bpf_mtap(ifp, m);
    return 0;
}

/*
 * The dynamic addition of a new device node must block all processes that are opening 
 * the last device so that no process will get an unexpected ENOENT 
 */
static void
bpf_make_dev_t(int maj)
{
        static int              bpf_growing = 0;
        unsigned int    cur_size = nbpfilter, i;

        if (nbpfilter >= bpf_maxdevices)
                return;

        while (bpf_growing) {
                /* Wait until new device has been created */
                (void)tsleep((caddr_t)&bpf_growing, PZERO, "bpf_growing", 0);
        }
        if (nbpfilter > cur_size) {
                /* other thread grew it already */
                return;
        }
        bpf_growing = 1;
        
        /* need to grow bpf_dtab first */
        if (nbpfilter == bpf_dtab_size) {
                int new_dtab_size;
                struct bpf_d **new_dtab = NULL;
                struct bpf_d **old_dtab = NULL;
                
                new_dtab_size = bpf_dtab_size + NBPFILTER;      
                new_dtab = (struct bpf_d **)_MALLOC(sizeof(struct bpf_d *) * new_dtab_size, M_DEVBUF, M_WAIT);
                if (new_dtab == 0) {
                        printf("bpf_make_dev_t: malloc bpf_dtab failed\n");
                        goto done;
                }
                if (bpf_dtab) {
                        bcopy(bpf_dtab, new_dtab, 
                                  sizeof(struct bpf_d *) * bpf_dtab_size);
                }
                bzero(new_dtab + bpf_dtab_size, 
                          sizeof(struct bpf_d *) * NBPFILTER);
                old_dtab = bpf_dtab;
                bpf_dtab = new_dtab;
                bpf_dtab_size = new_dtab_size;
                if (old_dtab != NULL)
                        _FREE(old_dtab, M_DEVBUF);
        }
        i = nbpfilter++;
        (void) devfs_make_node(makedev(maj, i),
                                DEVFS_CHAR, UID_ROOT, GID_WHEEL, 0600,
                                "bpf%d", i);
done:
        bpf_growing = 0;
        wakeup((caddr_t)&bpf_growing);
}

#endif

/*
 * Attach file to the bpf interface, i.e. make d listen on bp.
 * Must be called at splimp.
 */
static void
bpf_attachd(struct bpf_d *d, struct bpf_if *bp)
{
        /*
         * Point d at bp, and add d to the interface's list of listeners.
         * Finally, point the driver's bpf cookie at the interface so
         * it will divert packets to bpf.
         */
        d->bd_bif = bp;
        d->bd_next = bp->bif_dlist;
        bp->bif_dlist = d;

        bp->bif_ifp->if_bpf = bp;

#ifdef __APPLE__
        dlil_set_bpf_tap(bp->bif_ifp, BPF_TAP_INPUT_OUTPUT, bpf_tap_callback);
#endif
}

/*
 * Detach a file from its interface.
 */
static void
bpf_detachd(struct bpf_d *d)
{
        struct bpf_d **p;
        struct bpf_if *bp;
#ifdef __APPLE__
        struct ifnet  *ifp;

        ifp = d->bd_bif->bif_ifp;

#endif

        bp = d->bd_bif;
        /*
         * Check if this descriptor had requested promiscuous mode.
         * If so, turn it off.
         */
        if (d->bd_promisc) {
                d->bd_promisc = 0;
                if (ifnet_set_promiscuous(bp->bif_ifp, 0))
                        /*
                         * Something is really wrong if we were able to put
                         * the driver into promiscuous mode, but can't
                         * take it out.
                         * Most likely the network interface is gone.
                         */
                        printf("bpf: ifnet_set_promiscuous failed");
        }
        /* Remove d from the interface's descriptor list. */
        p = &bp->bif_dlist;
        while (*p != d) {
                p = &(*p)->bd_next;
                if (*p == 0)
                        panic("bpf_detachd: descriptor not in list");
        }
        *p = (*p)->bd_next;
        if (bp->bif_dlist == 0) {
                /*
                 * Let the driver know that there are no more listeners.
                 */
                if (ifp->if_set_bpf_tap)
                        (*ifp->if_set_bpf_tap)(ifp, BPF_TAP_DISABLE, 0);
                d->bd_bif->bif_ifp->if_bpf = 0;
        }
        d->bd_bif = 0;
}


/*
 * Open ethernet device.  Returns ENXIO for illegal minor device number,
 * EBUSY if file is open by another process.
 */
/* ARGSUSED */
        int
bpfopen(dev_t dev, __unused int flags, __unused int fmt, __unused struct proc *p)
{
        register struct bpf_d *d;

        if ((unsigned int) minor(dev) >= nbpfilter)
                return (ENXIO);
                
        /* 
         * New device nodes are created on demand when opening the last one. 
         * The programming model is for processes to loop on the minor starting at 0 
         * as long as EBUSY is returned. The loop stops when either the open succeeds or 
         * an error other that EBUSY is returned. That means that bpf_make_dev_t() must 
         * block all processes that are opening the last  node. If not all 
         * processes are blocked, they could unexpectedly get ENOENT and abort their 
         * opening loop.
         */
        if ((unsigned int) minor(dev) == (nbpfilter - 1))
                bpf_make_dev_t(major(dev));

        /*
         * Each minor can be opened by only one process.  If the requested 
         * minor is in use, return EBUSY.
         *
         * Important: bpfopen() and bpfclose() have to check and set the status of a device
         * in the same lockin context otherwise the device may be leaked because the vnode use count 
         * will be unpextectly greater than 1 when close() is called.
         */
        if (bpf_dtab[minor(dev)] == 0)
                bpf_dtab[minor(dev)] = (void *)1;       /* Mark opening */
        else
                return (EBUSY);

        d = (struct bpf_d *)_MALLOC(sizeof(struct bpf_d), M_DEVBUF, M_WAIT);
        if (d == NULL) {
                /* this really is a catastrophic failure */
                printf("bpfopen: malloc bpf_d failed\n");
                bpf_dtab[minor(dev)] = 0;
                return ENOMEM;
        }
        bzero(d, sizeof(struct bpf_d));
        
        /*
         * It is not necessary to take the BPF lock here because no other 
         * thread can access the device until it is marked opened...
         */
        
        /* Mark "in use" and do most initialization. */
        d->bd_bufsize = bpf_bufsize;
        d->bd_sig = SIGIO;
        d->bd_seesent = 1;
        bpf_dtab[minor(dev)] = d;                               /* Mark opened */

        return (0);
}

/*
 * Close the descriptor by detaching it from its interface,
 * deallocating its buffers, and marking it free.
 */
/* ARGSUSED */
        int
bpfclose(dev_t dev, __unused int flags, __unused int fmt, __unused struct proc *p)
{
        register struct bpf_d *d;

        d = bpf_dtab[minor(dev)];
        if (d == 0 || d == (void *)1)
                return (ENXIO);
        
        bpf_dtab[minor(dev)] = (void *)1;               /* Mark closing */

        /* Take BPF lock to ensure no other thread is using the device */
        lck_mtx_lock(bpf_mlock);

        if (d->bd_bif)
                bpf_detachd(d);
        selthreadclear(&d->bd_sel);
        bpf_freed(d);

        lck_mtx_unlock(bpf_mlock);
        
        /* Mark free in same context as bpfopen comes to check */
        bpf_dtab[minor(dev)] = 0;                               /* Mark closed */
        _FREE(d, M_DEVBUF);
        
        return (0);
}


#define BPF_SLEEP bpf_sleep

static int
bpf_sleep(struct bpf_d *d, int pri, const char *wmesg, int timo)
{
        register int st;

        lck_mtx_unlock(bpf_mlock);
        
        st = tsleep((caddr_t)d, pri, wmesg, timo);
        
        lck_mtx_lock(bpf_mlock);
        
        return st;
}

/*
 * Rotate the packet buffers in descriptor d.  Move the store buffer
 * into the hold slot, and the free buffer into the store slot.
 * Zero the length of the new store buffer.
 */
#define ROTATE_BUFFERS(d) \
        (d)->bd_hbuf = (d)->bd_sbuf; \
        (d)->bd_hlen = (d)->bd_slen; \
        (d)->bd_sbuf = (d)->bd_fbuf; \
        (d)->bd_slen = 0; \
        (d)->bd_fbuf = 0;
/*
 *  bpfread - read next chunk of packets from buffers
 */
        int
bpfread(dev_t dev, struct uio *uio, int ioflag)
{
        register struct bpf_d *d;
        int error;
        int s;

        d = bpf_dtab[minor(dev)];
        if (d == 0 || d == (void *)1)
                return (ENXIO);

        lck_mtx_lock(bpf_mlock);


        /*
         * Restrict application to use a buffer the same size as
         * as kernel buffers.
         */
        // LP64todo - fix this
        if (uio->uio_resid != d->bd_bufsize) {
                lck_mtx_unlock(bpf_mlock);
                return (EINVAL);
        }

        s = splimp();
        /*
         * If the hold buffer is empty, then do a timed sleep, which
         * ends when the timeout expires or when enough packets
         * have arrived to fill the store buffer.
         */
        while (d->bd_hbuf == 0) {
                if (d->bd_immediate && d->bd_slen != 0) {
                        /*
                         * A packet(s) either arrived since the previous
                         * read or arrived while we were asleep.
                         * Rotate the buffers and return what's here.
                         */
                        ROTATE_BUFFERS(d);
                        break;
                }

                /*
                 * No data is available, check to see if the bpf device
                 * is still pointed at a real interface.  If not, return
                 * ENXIO so that the userland process knows to rebind
                 * it before using it again.
                 */
                if (d->bd_bif == NULL) {
                        splx(s);
                        lck_mtx_unlock(bpf_mlock);
                        return (ENXIO);
                }
                
                if (ioflag & IO_NDELAY)
                        error = EWOULDBLOCK;
                else
                        error = BPF_SLEEP(d, PRINET|PCATCH, "bpf",
                                          d->bd_rtout);
                if (error == EINTR || error == ERESTART) {
                        splx(s);
                        lck_mtx_unlock(bpf_mlock);
                        return (error);
                }
                if (error == EWOULDBLOCK) {
                        /*
                         * On a timeout, return what's in the buffer,
                         * which may be nothing.  If there is something
                         * in the store buffer, we can rotate the buffers.
                         */
                        if (d->bd_hbuf)
                                /*
                                 * We filled up the buffer in between
                                 * getting the timeout and arriving
                                 * here, so we don't need to rotate.
                                 */
                                break;

                        if (d->bd_slen == 0) {
                                splx(s);
                                lck_mtx_unlock(bpf_mlock);
                                return (0);
                        }
                        ROTATE_BUFFERS(d);
                        break;
                }
        }
        /*
         * At this point, we know we have something in the hold slot.
         */
        splx(s);

        /*
         * Move data from hold buffer into user space.
         * We know the entire buffer is transferred since
         * we checked above that the read buffer is bpf_bufsize bytes.
         */
        error = UIOMOVE(d->bd_hbuf, d->bd_hlen, UIO_READ, uio);

        s = splimp();
        d->bd_fbuf = d->bd_hbuf;
        d->bd_hbuf = 0;
        d->bd_hlen = 0;
        splx(s);
        lck_mtx_unlock(bpf_mlock);
        return (error);
}


/*
 * If there are processes sleeping on this descriptor, wake them up.
 */
static void
bpf_wakeup(struct bpf_d *d)
{
        wakeup((caddr_t)d);
        if (d->bd_async && d->bd_sig && d->bd_sigio)
                pgsigio(d->bd_sigio, d->bd_sig, 0);

#if BSD >= 199103
        selwakeup(&d->bd_sel);
#ifndef __APPLE__
        /* XXX */
        d->bd_sel.si_pid = 0;
#endif
#else
        if (d->bd_selproc) {
                selwakeup(d->bd_selproc, (int)d->bd_selcoll);
                d->bd_selcoll = 0;
                d->bd_selproc = 0;
        }
#endif
}

/* keep in sync with bpf_movein above: */
#define MAX_DATALINK_HDR_LEN    (sizeof(struct firewire_header))

        int
bpfwrite(dev_t dev, struct uio *uio, __unused int ioflag)
{
        register struct bpf_d *d;
        struct ifnet *ifp;
        struct mbuf *m;
        int error;
        char              dst_buf[SOCKADDR_HDR_LEN + MAX_DATALINK_HDR_LEN];
        int datlen;

        d = bpf_dtab[minor(dev)];
        if (d == 0 || d == (void *)1)
                return (ENXIO);
        
        lck_mtx_lock(bpf_mlock);
        
        if (d->bd_bif == 0) {
                lck_mtx_unlock(bpf_mlock);
             return (ENXIO);
        }

        ifp = d->bd_bif->bif_ifp;

        if (uio->uio_resid == 0) {
                lck_mtx_unlock(bpf_mlock);
             return (0);
        }
        ((struct sockaddr *)dst_buf)->sa_len = sizeof(dst_buf);
        error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, &m, 
                           d->bd_hdrcmplt ? 0 : (struct sockaddr *)dst_buf, &datlen);
        if (error) {
                lck_mtx_unlock(bpf_mlock);
             return (error);
        }

        if ((unsigned)datlen > ifp->if_mtu) {
                lck_mtx_unlock(bpf_mlock);
             return (EMSGSIZE);
        }

        lck_mtx_unlock(bpf_mlock);

        if (d->bd_hdrcmplt) {
                error = dlil_output(ifp, 0, m, NULL, NULL, 1);
        }
        else {
                error = dlil_output(ifp, PF_INET, m, NULL, (struct sockaddr *)dst_buf, 0);
        }
        
        /*
         * The driver frees the mbuf.
         */
        return (error);
}

/*
 * Reset a descriptor by flushing its packet buffer and clearing the
 * receive and drop counts.  Should be called at splimp.
 */
static void
reset_d(struct bpf_d *d)
{
        if (d->bd_hbuf) {
                /* Free the hold buffer. */
                d->bd_fbuf = d->bd_hbuf;
                d->bd_hbuf = 0;
        }
        d->bd_slen = 0;
        d->bd_hlen = 0;
        d->bd_rcount = 0;
        d->bd_dcount = 0;
}

/*
 *  FIONREAD            Check for read packet available.
 *  SIOCGIFADDR         Get interface address - convenient hook to driver.
 *  BIOCGBLEN           Get buffer len [for read()].
 *  BIOCSETF            Set ethernet read filter.
 *  BIOCFLUSH           Flush read packet buffer.
 *  BIOCPROMISC         Put interface into promiscuous mode.
 *  BIOCGDLT            Get link layer type.
 *  BIOCGETIF           Get interface name.
 *  BIOCSETIF           Set interface.
 *  BIOCSRTIMEOUT       Set read timeout.
 *  BIOCGRTIMEOUT       Get read timeout.
 *  BIOCGSTATS          Get packet stats.
 *  BIOCIMMEDIATE       Set immediate mode.
 *  BIOCVERSION         Get filter language version.
 *  BIOCGHDRCMPLT       Get "header already complete" flag
 *  BIOCSHDRCMPLT       Set "header already complete" flag
 *  BIOCGSEESENT        Get "see packets sent" flag
 *  BIOCSSEESENT        Set "see packets sent" flag
 */
/* ARGSUSED */
int
bpfioctl(dev_t dev, u_long cmd, caddr_t addr, __unused int flags, struct proc *p)
{
        register struct bpf_d *d;
        int s, error = 0;

        d = bpf_dtab[minor(dev)];
        if (d == 0 || d == (void *)1)
                return (ENXIO);

        lck_mtx_lock(bpf_mlock);

        switch (cmd) {

        default:
                error = EINVAL;
                break;

        /*
         * Check for read packet available.
         */
        case FIONREAD:
                {
                        int n;

                        s = splimp();
                        n = d->bd_slen;
                        if (d->bd_hbuf)
                                n += d->bd_hlen;
                        splx(s);

                        *(int *)addr = n;
                        break;
                }

        case SIOCGIFADDR:
                {
                        struct ifnet *ifp;

                        if (d->bd_bif == 0)
                                error = EINVAL;
                        else {
                                ifp = d->bd_bif->bif_ifp;
                                error = dlil_ioctl(0, ifp, cmd, addr);
                        }
                        break;
                }

        /*
         * Get buffer len [for read()].
         */
        case BIOCGBLEN:
                *(u_int *)addr = d->bd_bufsize;
                break;

        /*
         * Set buffer length.
         */
        case BIOCSBLEN:
#if BSD < 199103
                error = EINVAL;
#else
                if (d->bd_bif != 0)
                        error = EINVAL;
                else {
                        register u_int size = *(u_int *)addr;

                        if (size > bpf_maxbufsize)
                                *(u_int *)addr = size = bpf_maxbufsize;
                        else if (size < BPF_MINBUFSIZE)
                                *(u_int *)addr = size = BPF_MINBUFSIZE;
                        d->bd_bufsize = size;
                }
#endif
                break;

        /*
         * Set link layer read filter.
         */
        case BIOCSETF:
                if (proc_is64bit(p)) {
                        error = bpf_setf(d, (struct user_bpf_program *)addr);
                }
                else {
                        struct bpf_program *    tmpp;
                        struct user_bpf_program tmp;

                        tmpp = (struct bpf_program *)addr;
                        tmp.bf_len = tmpp->bf_len;
                        tmp.bf_insns = CAST_USER_ADDR_T(tmpp->bf_insns);
                        error = bpf_setf(d, &tmp);
                }
                break;

        /*
         * Flush read packet buffer.
         */
        case BIOCFLUSH:
                s = splimp();
                reset_d(d);
                splx(s);
                break;

        /*
         * Put interface into promiscuous mode.
         */
        case BIOCPROMISC:
                if (d->bd_bif == 0) {
                        /*
                         * No interface attached yet.
                         */
                        error = EINVAL;
                        break;
                }
                s = splimp();
                if (d->bd_promisc == 0) {
                        error = ifnet_set_promiscuous(d->bd_bif->bif_ifp, 1);
                        if (error == 0)
                                d->bd_promisc = 1;
                }
                splx(s);
                break;

        /*
         * Get device parameters.
         */
        case BIOCGDLT:
                if (d->bd_bif == 0)
                        error = EINVAL;
                else
                        *(u_int *)addr = d->bd_bif->bif_dlt;
                break;

        /*
         * Get interface name.
         */
        case BIOCGETIF:
                if (d->bd_bif == 0)
                        error = EINVAL;
                else {
                        struct ifnet *const ifp = d->bd_bif->bif_ifp;
                        struct ifreq *const ifr = (struct ifreq *)addr;

                        snprintf(ifr->ifr_name, sizeof(ifr->ifr_name),
                            "%s%d", ifp->if_name, ifp->if_unit);
                }
                break;

        /*
         * Set interface.
         */
        case BIOCSETIF:
                error = bpf_setif(d, (struct ifreq *)addr);
                break;

        /*
         * Set read timeout.
         */
        case BIOCSRTIMEOUT:
                {
                        struct timeval *tv = (struct timeval *)addr;

                        /*
                         * Subtract 1 tick from tvtohz() since this isn't
                         * a one-shot timer.
                         */
                        if ((error = itimerfix(tv)) == 0)
                                d->bd_rtout = tvtohz(tv) - 1;
                        break;
                }

        /*
         * Get read timeout.
         */
        case BIOCGRTIMEOUT:
                {
                        struct timeval *tv = (struct timeval *)addr;

                        tv->tv_sec = d->bd_rtout / hz;
                        tv->tv_usec = (d->bd_rtout % hz) * tick;
                        break;
                }

        /*
         * Get packet stats.
         */
        case BIOCGSTATS:
                {
                        struct bpf_stat *bs = (struct bpf_stat *)addr;

                        bs->bs_recv = d->bd_rcount;
                        bs->bs_drop = d->bd_dcount;
                        break;
                }

        /*
         * Set immediate mode.
         */
        case BIOCIMMEDIATE:
                d->bd_immediate = *(u_int *)addr;
                break;

        case BIOCVERSION:
                {
                        struct bpf_version *bv = (struct bpf_version *)addr;

                        bv->bv_major = BPF_MAJOR_VERSION;
                        bv->bv_minor = BPF_MINOR_VERSION;
                        break;
                }

        /*
         * Get "header already complete" flag
         */
        case BIOCGHDRCMPLT:
                *(u_int *)addr = d->bd_hdrcmplt;
                break;

        /*
         * Set "header already complete" flag
         */
        case BIOCSHDRCMPLT:
                d->bd_hdrcmplt = *(u_int *)addr ? 1 : 0;
                break;

        /*
         * Get "see sent packets" flag
         */
        case BIOCGSEESENT:
                *(u_int *)addr = d->bd_seesent;
                break;

        /*
         * Set "see sent packets" flag
         */
        case BIOCSSEESENT:
                d->bd_seesent = *(u_int *)addr;
                break;

        case FIONBIO:           /* Non-blocking I/O */
                break;

        case FIOASYNC:          /* Send signal on receive packets */
                d->bd_async = *(int *)addr;
                break;
#ifndef __APPLE__
        case FIOSETOWN:
                error = fsetown(*(int *)addr, &d->bd_sigio);
                break;

        case FIOGETOWN:
                *(int *)addr = fgetown(d->bd_sigio);
                break;

        /* This is deprecated, FIOSETOWN should be used instead. */
        case TIOCSPGRP:
                error = fsetown(-(*(int *)addr), &d->bd_sigio);
                break;

        /* This is deprecated, FIOGETOWN should be used instead. */
        case TIOCGPGRP:
                *(int *)addr = -fgetown(d->bd_sigio);
                break;
#endif
        case BIOCSRSIG:         /* Set receive signal */
                {
                        u_int sig;

                        sig = *(u_int *)addr;

                        if (sig >= NSIG)
                                error = EINVAL;
                        else
                                d->bd_sig = sig;
                        break;
                }
        case BIOCGRSIG:
                *(u_int *)addr = d->bd_sig;
                break;
        }
        
        lck_mtx_unlock(bpf_mlock);
        
        return (error);
}

/*
 * Set d's packet filter program to fp.  If this file already has a filter,
 * free it and replace it.  Returns EINVAL for bogus requests.
 */
static int
bpf_setf(struct bpf_d *d, struct user_bpf_program *fp)
{
        struct bpf_insn *fcode, *old;
        u_int flen, size;
        int s;

        old = d->bd_filter;
        if (fp->bf_insns == USER_ADDR_NULL) {
                if (fp->bf_len != 0)
                        return (EINVAL);
                s = splimp();
                d->bd_filter = 0;
                reset_d(d);
                splx(s);
                if (old != 0)
                        FREE((caddr_t)old, M_DEVBUF);
                return (0);
        }
        flen = fp->bf_len;
        if (flen > BPF_MAXINSNS)
                return (EINVAL);

        size = flen * sizeof(struct bpf_insn);
        fcode = (struct bpf_insn *) _MALLOC(size, M_DEVBUF, M_WAIT);
#ifdef __APPLE__
        if (fcode == NULL)
                return (ENOBUFS);
#endif
        if (copyin(fp->bf_insns, (caddr_t)fcode, size) == 0 &&
            bpf_validate(fcode, (int)flen)) {
                s = splimp();
                d->bd_filter = fcode;
                reset_d(d);
                splx(s);
                if (old != 0)
                        FREE((caddr_t)old, M_DEVBUF);

                return (0);
        }
        FREE((caddr_t)fcode, M_DEVBUF);
        return (EINVAL);
}

/*
 * Detach a file from its current interface (if attached at all) and attach
 * to the interface indicated by the name stored in ifr.
 * Return an errno or 0.
 */
static int
bpf_setif(struct bpf_d *d, struct ifreq *ifr)
{
        struct bpf_if *bp;
        int s, error;
        struct ifnet *theywant;

        theywant = ifunit(ifr->ifr_name);
        if (theywant == 0)
                return ENXIO;

        /*
         * Look through attached interfaces for the named one.
         */
        for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) {
                struct ifnet *ifp = bp->bif_ifp;

                if (ifp == 0 || ifp != theywant)
                        continue;
                /*
                 * We found the requested interface.
                 * If it's not up, return an error.
                 * Allocate the packet buffers if we need to.
                 * If we're already attached to requested interface,
                 * just flush the buffer.
                 */
                if ((ifp->if_flags & IFF_UP) == 0)
                        return (ENETDOWN);

                if (d->bd_sbuf == 0) {
                        error = bpf_allocbufs(d);
                        if (error != 0)
                                return (error);
                }
                s = splimp();
                if (bp != d->bd_bif) {
                        if (d->bd_bif)
                                /*
                                 * Detach if attached to something else.
                                 */
                                bpf_detachd(d);

                        bpf_attachd(d, bp);
                }
                reset_d(d);
                splx(s);
                return (0);
        }
        /* Not found. */
        return (ENXIO);
}

/*
 * Support for select() and poll() system calls
 *
 * Return true iff the specific operation will not block indefinitely.
 * Otherwise, return false but make a note that a selwakeup() must be done.
 */
int
bpfpoll(dev_t dev, int events, void * wql, struct proc *p)
{
        register struct bpf_d *d;
        register int s;
        int revents = 0;

        d = bpf_dtab[minor(dev)];
        if (d == 0 || d == (void *)1)
                return (ENXIO);

        lck_mtx_lock(bpf_mlock);

        /*
         * An imitation of the FIONREAD ioctl code.
         */
        if (d->bd_bif == NULL) {
                lck_mtx_unlock(bpf_mlock);
                return (ENXIO);
        }

        s = splimp();
        if (events & (POLLIN | POLLRDNORM)) {
                if (d->bd_hlen != 0 || (d->bd_immediate && d->bd_slen != 0))
                        revents |= events & (POLLIN | POLLRDNORM);
                else
                        selrecord(p, &d->bd_sel, wql);
        }
        splx(s);

        lck_mtx_unlock(bpf_mlock);
        return (revents);
}

/*
 * Incoming linkage from device drivers.  Process the packet pkt, of length
 * pktlen, which is stored in a contiguous buffer.  The packet is parsed
 * by each process' filter, and if accepted, stashed into the corresponding
 * buffer.
 */
void
bpf_tap(struct ifnet *ifp, u_char *pkt, u_int pktlen)
{
        struct bpf_if *bp;
        register struct bpf_d *d;
        register u_int slen;
        /*
         * Note that the ipl does not have to be raised at this point.
         * The only problem that could arise here is that if two different
         * interfaces shared any data.  This is not the case.
         */
        lck_mtx_lock(bpf_mlock);
        
        bp = ifp->if_bpf;
#ifdef __APPLE__
        if (bp) {
#endif
                for (d = bp->bif_dlist; d != 0; d = d->bd_next) {
                        ++d->bd_rcount;
                        slen = bpf_filter(d->bd_filter, pkt, pktlen, pktlen);
                        if (slen != 0)
                                catchpacket(d, pkt, pktlen, slen, bcopy);
                }
#ifdef __APPLE__
    }
        lck_mtx_unlock(bpf_mlock);
#endif
}

/*
 * Copy data from an mbuf chain into a buffer.  This code is derived
 * from m_copydata in sys/uipc_mbuf.c.
 */
static void
bpf_mcopy(const void *src_arg, void *dst_arg, size_t len)
{
        const struct mbuf *m;
        u_int count;
        u_char *dst;

        m = src_arg;
        dst = dst_arg;
        while (len > 0) {
                if (m == 0)
                        panic("bpf_mcopy");
                count = min(m->m_len, len);
                bcopy(mtod(m, const void *), dst, count);
                m = m->m_next;
                dst += count;
                len -= count;
        }
}

/*
 * Incoming linkage from device drivers, when packet is in an mbuf chain.
 */
void
bpf_mtap(struct ifnet *ifp, struct mbuf *m)
{
        struct bpf_if *bp;
        struct bpf_d *d;
        u_int pktlen, slen;
        struct mbuf *m0;

        lck_mtx_lock(bpf_mlock);
        
        bp = ifp->if_bpf;
        if (bp) {
        pktlen = 0;
        for (m0 = m; m0 != 0; m0 = m0->m_next)
                pktlen += m0->m_len;
        
                for (d = bp->bif_dlist; d != 0; d = d->bd_next) {
                        if (!d->bd_seesent && (m->m_pkthdr.rcvif == NULL))
                                continue;
                        ++d->bd_rcount;
                        slen = bpf_filter(d->bd_filter, (u_char *)m, pktlen, 0);
                        if (slen != 0)
                                catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy);
                }
        }
        
        lck_mtx_unlock(bpf_mlock);
}

/*
 * Move the packet data from interface memory (pkt) into the
 * store buffer.  Return 1 if it's time to wakeup a listener (buffer full),
 * otherwise 0.  "copy" is the routine called to do the actual data
 * transfer.  bcopy is passed in to copy contiguous chunks, while
 * bpf_mcopy is passed in to copy mbuf chains.  In the latter case,
 * pkt is really an mbuf.
 */
static void
catchpacket(struct bpf_d *d, u_char *pkt, u_int pktlen, u_int snaplen, 
        void (*cpfn)(const void *, void *, size_t))
{
        register struct bpf_hdr *hp;
        register int totlen, curlen;
        register int hdrlen = d->bd_bif->bif_hdrlen;
        /*
         * Figure out how many bytes to move.  If the packet is
         * greater or equal to the snapshot length, transfer that
         * much.  Otherwise, transfer the whole packet (unless
         * we hit the buffer size limit).
         */
        totlen = hdrlen + min(snaplen, pktlen);
        if (totlen > d->bd_bufsize)
                totlen = d->bd_bufsize;

        /*
         * Round up the end of the previous packet to the next longword.
         */
        curlen = BPF_WORDALIGN(d->bd_slen);
        if (curlen + totlen > d->bd_bufsize) {
                /*
                 * This packet will overflow the storage buffer.
                 * Rotate the buffers if we can, then wakeup any
                 * pending reads.
                 */
                if (d->bd_fbuf == 0) {
                        /*
                         * We haven't completed the previous read yet,
                         * so drop the packet.
                         */
                        ++d->bd_dcount;
                        return;
                }
                ROTATE_BUFFERS(d);
                bpf_wakeup(d);
                curlen = 0;
        }
        else if (d->bd_immediate)
                /*
                 * Immediate mode is set.  A packet arrived so any
                 * reads should be woken up.
                 */
                bpf_wakeup(d);

        /*
         * Append the bpf header.
         */
        hp = (struct bpf_hdr *)(d->bd_sbuf + curlen);
#if BSD >= 199103
        microtime(&hp->bh_tstamp);
#elif defined(sun)
        uniqtime(&hp->bh_tstamp);
#else
        hp->bh_tstamp = time;
#endif
        hp->bh_datalen = pktlen;
        hp->bh_hdrlen = hdrlen;
        /*
         * Copy the packet data into the store buffer and update its length.
         */
        (*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen));
        d->bd_slen = curlen + totlen;
}

/*
 * Initialize all nonzero fields of a descriptor.
 */
static int
bpf_allocbufs(struct bpf_d *d)
{
        d->bd_fbuf = (caddr_t) _MALLOC(d->bd_bufsize, M_DEVBUF, M_WAIT);
        if (d->bd_fbuf == 0)
                return (ENOBUFS);

        d->bd_sbuf = (caddr_t) _MALLOC(d->bd_bufsize, M_DEVBUF, M_WAIT);
        if (d->bd_sbuf == 0) {
                FREE(d->bd_fbuf, M_DEVBUF);
                return (ENOBUFS);
        }
        d->bd_slen = 0;
        d->bd_hlen = 0;
        return (0);
}

/*
 * Free buffers currently in use by a descriptor.
 * Called on close.
 */
static void
bpf_freed(struct bpf_d *d)
{
        /*
         * We don't need to lock out interrupts since this descriptor has
         * been detached from its interface and it yet hasn't been marked
         * free.
         */
        if (d->bd_sbuf != 0) {
                FREE(d->bd_sbuf, M_DEVBUF);
                if (d->bd_hbuf != 0)
                        FREE(d->bd_hbuf, M_DEVBUF);
                if (d->bd_fbuf != 0)
                        FREE(d->bd_fbuf, M_DEVBUF);
        }
        if (d->bd_filter)
                FREE((caddr_t)d->bd_filter, M_DEVBUF);
}

/*
 * Attach an interface to bpf.  driverp is a pointer to a (struct bpf_if *)
 * in the driver's softc; dlt is the link layer type; hdrlen is the fixed
 * size of the link header (variable length headers not yet supported).
 */
void
bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
{
        struct bpf_if *bp;
        bp = (struct bpf_if *) _MALLOC(sizeof(*bp), M_DEVBUF, M_WAIT);
        if (bp == 0)
                panic("bpfattach");

        lck_mtx_lock(bpf_mlock);

        bp->bif_dlist = 0;
        bp->bif_ifp = ifp;
        bp->bif_dlt = dlt;

        bp->bif_next = bpf_iflist;
        bpf_iflist = bp;

        bp->bif_ifp->if_bpf = 0;

        /*
         * Compute the length of the bpf header.  This is not necessarily
         * equal to SIZEOF_BPF_HDR because we want to insert spacing such
         * that the network layer header begins on a longword boundary (for
         * performance reasons and to alleviate alignment restrictions).
         */
        bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen;
        
        /* Take a reference on the interface */
        ifp_reference(ifp);

        lck_mtx_unlock(bpf_mlock);

#ifndef __APPLE__
        if (bootverbose)
                printf("bpf: %s%d attached\n", ifp->if_name, ifp->if_unit);
#endif
}

/*
 * Detach bpf from an interface.  This involves detaching each descriptor
 * associated with the interface, and leaving bd_bif NULL.  Notify each
 * descriptor as it's detached so that any sleepers wake up and get
 * ENXIO.
 */
void
bpfdetach(struct ifnet *ifp)
{
        struct bpf_if   *bp, *bp_prev;
        struct bpf_d    *d;
        int     s;

        s = splimp();
        
        lck_mtx_lock(bpf_mlock);

        /* Locate BPF interface information */
        bp_prev = NULL;
        for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
                if (ifp == bp->bif_ifp)
                        break;
                bp_prev = bp;
        }

#ifdef __APPLE__
        /* Check for no BPF interface information */
        if (bp == NULL) {
                return;
        }
#endif

        /* Interface wasn't attached */
        if (bp->bif_ifp == NULL) {
                splx(s);
#ifndef __APPLE__
                printf("bpfdetach: %s%d was not attached\n", ifp->if_name,
                    ifp->if_unit);
#endif
                return;
        }

        while ((d = bp->bif_dlist) != NULL) {
                bpf_detachd(d);
                bpf_wakeup(d);
        }

        if (bp_prev) {
                bp_prev->bif_next = bp->bif_next;
        } else {
                bpf_iflist = bp->bif_next;
        }
        
        ifp_release(ifp);
        
        lck_mtx_unlock(bpf_mlock);

        FREE(bp, M_DEVBUF);

        splx(s);
}

void
bpf_init(__unused void *unused)
{
#ifdef __APPLE__
        int     i;
        int     maj;

        if (bpf_devsw_installed == 0) {
                bpf_devsw_installed = 1;

        bpf_mlock_grp_attr = lck_grp_attr_alloc_init();
        lck_grp_attr_setdefault(bpf_mlock_grp_attr);

        bpf_mlock_grp = lck_grp_alloc_init("bpf", bpf_mlock_grp_attr);

        bpf_mlock_attr = lck_attr_alloc_init();
        lck_attr_setdefault(bpf_mlock_attr);

        bpf_mlock = lck_mtx_alloc_init(bpf_mlock_grp, bpf_mlock_attr);

                if (bpf_mlock == 0) {
                        printf("bpf_init: failed to allocate bpf_mlock\n");
                        bpf_devsw_installed = 0;
                        return;
                }
                
                maj = cdevsw_add(CDEV_MAJOR, &bpf_cdevsw);
                if (maj == -1) {
                        if (bpf_mlock)
                                lck_mtx_free(bpf_mlock, bpf_mlock_grp);
                        if (bpf_mlock_attr)
                                lck_attr_free(bpf_mlock_attr);
                        if (bpf_mlock_grp)
                                lck_grp_free(bpf_mlock_grp);
                        if (bpf_mlock_grp_attr)
                                lck_grp_attr_free(bpf_mlock_grp_attr);
                        
                        bpf_mlock = 0;
                        bpf_mlock_attr = 0;
                        bpf_mlock_grp = 0;
                        bpf_mlock_grp_attr = 0;
                        bpf_devsw_installed = 0;
                        printf("bpf_init: failed to allocate a major number!\n");
                        return;
                }

                for (i = 0 ; i < NBPFILTER; i++)
                        bpf_make_dev_t(maj);
        }
#else
        cdevsw_add(&bpf_cdevsw);
#endif
}

#ifndef __APPLE__
SYSINIT(bpfdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,bpf_drvinit,NULL)
#endif

#else /* !BPF */
#ifndef __APPLE__
/*
 * NOP stubs to allow bpf-using drivers to load and function.
 *
 * A 'better' implementation would allow the core bpf functionality
 * to be loaded at runtime.
 */

void
bpf_tap(ifp, pkt, pktlen)
        struct ifnet *ifp;
        register u_char *pkt;
        register u_int pktlen;
{
}

void
bpf_mtap(ifp, m)
        struct ifnet *ifp;
        struct mbuf *m;
{
}

void
bpfattach(ifp, dlt, hdrlen)
        struct ifnet *ifp;
        u_int dlt, hdrlen;
{
}

void
bpfdetach(ifp)
        struct ifnet *ifp;
{
}

u_int
bpf_filter(pc, p, wirelen, buflen)
        register const struct bpf_insn *pc;
        register u_char *p;
        u_int wirelen;
        register u_int buflen;
{
        return -1;      /* "no filter" behaviour */
}
#endif /* !defined(__APPLE__) */
#endif /* NBPFILTER > 0 */