xnu-7195.60.75.tar.gz

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

/*
 * Copyright (c) 2000-2020 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_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_OSREFERENCE_LICENSE_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 $
 */
/*
 * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
 * support for mandatory and extensible security protections.  This notice
 * is included in support of clause 2.2 (b) of the Apple Public License,
 * Version 2.0.
 */

#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>
#include <sys/file_internal.h>
#include <sys/event.h>

#include <sys/poll.h>

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

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

#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#include <netinet/tcp.h>
#include <netinet/tcp_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <netinet/if_ether.h>
#include <netinet/isakmp.h>
#include <netinet6/esp.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <net/firewire.h>

#include <miscfs/devfs/devfs.h>
#include <net/dlil.h>
#include <net/pktap.h>

#include <kern/locks.h>
#include <kern/thread_call.h>
#include <libkern/section_keywords.h>

#include <os/log.h>

extern int tvtohz(struct timeval *);

#define BPF_BUFSIZE 4096
#define UIOMOVE(cp, len, code, uio) uiomove(cp, len, uio)

#define PRINET  26                      /* interruptible */

#define ISAKMP_HDR_SIZE (sizeof(struct isakmp) + sizeof(struct isakmp_gen))
#define ESP_HDR_SIZE sizeof(struct newesp)

typedef void (*pktcopyfunc_t)(const void *, void *, size_t);

/*
 * The default read buffer size is patchable.
 */
static unsigned int bpf_bufsize = BPF_BUFSIZE;
SYSCTL_INT(_debug, OID_AUTO, bpf_bufsize, CTLFLAG_RW | CTLFLAG_LOCKED,
    &bpf_bufsize, 0, "");

static int sysctl_bpf_maxbufsize SYSCTL_HANDLER_ARGS;
extern const int copysize_limit_panic;
#define BPF_MAXSIZE_CAP (copysize_limit_panic >> 1)
__private_extern__ unsigned int bpf_maxbufsize = BPF_MAXBUFSIZE;
SYSCTL_PROC(_debug, OID_AUTO, bpf_maxbufsize, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
    &bpf_maxbufsize, 0,
    sysctl_bpf_maxbufsize, "I", "Default BPF max buffer size");

static unsigned int bpf_maxdevices = 256;
SYSCTL_UINT(_debug, OID_AUTO, bpf_maxdevices, CTLFLAG_RW | CTLFLAG_LOCKED,
    &bpf_maxdevices, 0, "");
/*
 * bpf_wantpktap controls the defaul visibility of DLT_PKTAP
 * For OS X is off by default so process need to use the ioctl BPF_WANT_PKTAP
 * explicitly to be able to use DLT_PKTAP.
 */
#if !XNU_TARGET_OS_OSX
static unsigned int bpf_wantpktap = 1;
#else /* XNU_TARGET_OS_OSX */
static unsigned int bpf_wantpktap = 0;
#endif /* XNU_TARGET_OS_OSX */
SYSCTL_UINT(_debug, OID_AUTO, bpf_wantpktap, CTLFLAG_RW | CTLFLAG_LOCKED,
    &bpf_wantpktap, 0, "");

static int bpf_debug = 0;
SYSCTL_INT(_debug, OID_AUTO, bpf_debug, CTLFLAG_RW | CTLFLAG_LOCKED,
    &bpf_debug, 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:
 *  NULL: device not opened
 *  BPF_DEV_RESERVED: device opening or closing
 *  other: device <n> opened with pointer to storage
 */
#define BPF_DEV_RESERVED ((struct bpf_d *)(uintptr_t)1)
static struct bpf_d     **bpf_dtab = NULL;
static unsigned int bpf_dtab_size = 0;
static unsigned int     nbpfilter = 0;

decl_lck_mtx_data(static, bpf_mlock_data);
static lck_mtx_t                *bpf_mlock = &bpf_mlock_data;
static lck_grp_t                *bpf_mlock_grp;
static lck_grp_attr_t   *bpf_mlock_grp_attr;
static lck_attr_t               *bpf_mlock_attr;

#endif /* __APPLE__ */

static int      bpf_allocbufs(struct bpf_d *);
static errno_t  bpf_attachd(struct bpf_d *d, struct bpf_if *bp);
static int      bpf_detachd(struct bpf_d *d, int);
static void     bpf_freed(struct bpf_d *);
static int      bpf_movein(struct uio *, int,
    struct mbuf **, struct sockaddr *, int *);
static int      bpf_setif(struct bpf_d *, ifnet_t ifp, bool, bool);
static void     bpf_timed_out(void *, void *);
static void     bpf_wakeup(struct bpf_d *);
static u_int    get_pkt_trunc_len(u_char *, u_int);
static void     catchpacket(struct bpf_d *, struct bpf_packet *, u_int, int);
static void     reset_d(struct bpf_d *);
static int      bpf_setf(struct bpf_d *, u_int, user_addr_t, u_long);
static int      bpf_getdltlist(struct bpf_d *, caddr_t, struct proc *);
static int      bpf_setdlt(struct bpf_d *, u_int);
static int      bpf_set_traffic_class(struct bpf_d *, int);
static void     bpf_set_packet_service_class(struct mbuf *, int);

static void     bpf_acquire_d(struct bpf_d *);
static void     bpf_release_d(struct bpf_d *);

static  int bpf_devsw_installed;

void bpf_init(void *unused);
static 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        bpfselect;

/* Darwin's cdevsw struct differs slightly from BSDs */
#define CDEV_MAJOR 23
static const struct cdevsw bpf_cdevsw = {
        .d_open       = bpfopen,
        .d_close      = bpfclose,
        .d_read       = bpfread,
        .d_write      = bpfwrite,
        .d_ioctl      = bpfioctl,
        .d_stop       = eno_stop,
        .d_reset      = eno_reset,
        .d_ttys       = NULL,
        .d_select     = bpfselect,
        .d_mmap       = eno_mmap,
        .d_strategy   = eno_strat,
        .d_reserved_1 = eno_getc,
        .d_reserved_2 = eno_putc,
        .d_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;
        uint8_t sa_family;
        int hlen;

        switch (linktype) {
#if SLIP
        case DLT_SLIP:
                sa_family = AF_INET;
                hlen = 0;
                break;
#endif /* SLIP */

        case DLT_EN10MB:
                sa_family = AF_UNSPEC;
                /* XXX Would MAXLINKHDR be better? */
                hlen = sizeof(struct ether_header);
                break;

#if FDDI
        case DLT_FDDI:
#if defined(__FreeBSD__) || defined(__bsdi__)
                sa_family = AF_IMPLINK;
                hlen = 0;
#else
                sa_family = AF_UNSPEC;
                /* XXX 4(FORMAC)+6(dst)+6(src)+3(LLC)+5(SNAP) */
                hlen = 24;
#endif
                break;
#endif /* FDDI */

        case DLT_RAW:
        case DLT_NULL:
                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.
                 */
                sa_family = AF_UNSPEC;
                hlen = 12;      /* XXX 4(ATM_PH) + 3(LLC) + 5(SNAP) */
                break;
#endif

        case DLT_PPP:
                sa_family = AF_UNSPEC;
                hlen = 4;       /* This should match PPP_HDRLEN */
                break;

        case DLT_APPLE_IP_OVER_IEEE1394:
                sa_family = AF_UNSPEC;
                hlen = sizeof(struct firewire_header);
                break;

        case DLT_IEEE802_11:            /* IEEE 802.11 wireless */
                sa_family = AF_IEEE80211;
                hlen = 0;
                break;

        case DLT_IEEE802_11_RADIO:
                sa_family = AF_IEEE80211;
                hlen = 0;
                break;

        default:
                return EIO;
        }

        // LP64todo - fix this!
        len = uio_resid(uio);
        *datlen = len - hlen;
        if ((unsigned)len > MCLBYTES) {
                return EIO;
        }

        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.
                 */
                if ((hlen + SOCKADDR_HDR_LEN) > sockp->sa_len) {
                        return EIO;
                }
                sockp->sa_family = sa_family;
        } else {
                /*
                 * We're directly sending the packet data supplied by
                 * the user; we don't need to make room for the link
                 * header, and don't need the header length value any
                 * more, so set it to 0.
                 */
                hlen = 0;
        }

        MGETHDR(m, M_WAIT, MT_DATA);
        if (m == 0) {
                return ENOBUFS;
        }
        if ((unsigned)len > MHLEN) {
                MCLGET(m, M_WAIT);
                if ((m->m_flags & M_EXT) == 0) {
                        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;
                m->m_data += hlen; /* XXX */
                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) {
                goto bad;
        }

        /* Check for multicast destination */
        switch (linktype) {
        case DLT_EN10MB: {
                struct ether_header *eh;

                eh = mtod(m, struct ether_header *);
                if (ETHER_IS_MULTICAST(eh->ether_dhost)) {
                        if (_ether_cmp(etherbroadcastaddr,
                            eh->ether_dhost) == 0) {
                                m->m_flags |= M_BCAST;
                        } else {
                                m->m_flags |= M_MCAST;
                        }
                }
                break;
        }
        }

        return 0;
bad:
        m_freem(m);
        return error;
}

#ifdef __APPLE__

/*
 * 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.
 */
static errno_t
bpf_attachd(struct bpf_d *d, struct bpf_if *bp)
{
        int first = bp->bif_dlist == NULL;
        int     error = 0;

        /*
         * 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;

        /*
         * Take a reference on the device even if an error is returned
         * because we keep the device in the interface's list of listeners
         */
        bpf_acquire_d(d);

        if (first) {
                /* Find the default bpf entry for this ifp */
                if (bp->bif_ifp->if_bpf == NULL) {
                        struct bpf_if   *tmp, *primary = NULL;

                        for (tmp = bpf_iflist; tmp; tmp = tmp->bif_next) {
                                if (tmp->bif_ifp == bp->bif_ifp) {
                                        primary = tmp;
                                        break;
                                }
                        }
                        bp->bif_ifp->if_bpf = primary;
                }
                /* Only call dlil_set_bpf_tap for primary dlt */
                if (bp->bif_ifp->if_bpf == bp) {
                        dlil_set_bpf_tap(bp->bif_ifp, BPF_TAP_INPUT_OUTPUT,
                            bpf_tap_callback);
                }

                if (bp->bif_tap != NULL) {
                        error = bp->bif_tap(bp->bif_ifp, bp->bif_dlt,
                            BPF_TAP_INPUT_OUTPUT);
                }
        }

        /*
         * Reset the detach flags in case we previously detached an interface
         */
        d->bd_flags &= ~(BPF_DETACHING | BPF_DETACHED);

        if (bp->bif_dlt == DLT_PKTAP) {
                d->bd_flags |= BPF_FINALIZE_PKTAP;
        } else {
                d->bd_flags &= ~BPF_FINALIZE_PKTAP;
        }
        return error;
}

/*
 * Detach a file from its interface.
 *
 * Return 1 if was closed by some thread, 0 otherwise
 */
static int
bpf_detachd(struct bpf_d *d, int closing)
{
        struct bpf_d **p;
        struct bpf_if *bp;
        struct ifnet  *ifp;

        int bpf_closed = d->bd_flags & BPF_CLOSING;
        /*
         * Some other thread already detached
         */
        if ((d->bd_flags & (BPF_DETACHED | BPF_DETACHING)) != 0) {
                goto done;
        }
        /*
         * This thread is doing the detach
         */
        d->bd_flags |= BPF_DETACHING;

        ifp = d->bd_bif->bif_ifp;
        bp = d->bd_bif;

        if (bpf_debug != 0) {
                printf("%s: %llx %s%s\n",
                    __func__, (uint64_t)VM_KERNEL_ADDRPERM(d),
                    if_name(ifp), closing ? " closing" : "");
        }

        /* 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.
                 */
                /* Only call dlil_set_bpf_tap for primary dlt */
                if (bp->bif_ifp->if_bpf == bp) {
                        dlil_set_bpf_tap(ifp, BPF_TAP_DISABLE, NULL);
                }
                if (bp->bif_tap) {
                        bp->bif_tap(ifp, bp->bif_dlt, BPF_TAP_DISABLE);
                }

                for (bp = bpf_iflist; bp; bp = bp->bif_next) {
                        if (bp->bif_ifp == ifp && bp->bif_dlist != 0) {
                                break;
                        }
                }
                if (bp == NULL) {
                        ifp->if_bpf = NULL;
                }
        }
        d->bd_bif = NULL;
        /*
         * Check if this descriptor had requested promiscuous mode.
         * If so, turn it off.
         */
        if (d->bd_promisc) {
                d->bd_promisc = 0;
                lck_mtx_unlock(bpf_mlock);
                if (ifnet_set_promiscuous(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("%s: ifnet_set_promiscuous failed\n", __func__);
                }
                lck_mtx_lock(bpf_mlock);
        }

        /*
         * Wake up other thread that are waiting for this thread to finish
         * detaching
         */
        d->bd_flags &= ~BPF_DETACHING;
        d->bd_flags |= BPF_DETACHED;

        /* Refresh the local variable as d could have been modified */
        bpf_closed = d->bd_flags & BPF_CLOSING;
        /*
         * Note that We've kept the reference because we may have dropped
         * the lock when turning off promiscuous mode
         */
        bpf_release_d(d);

done:
        /*
         * When closing makes sure no other thread refer to the bpf_d
         */
        if (bpf_debug != 0) {
                printf("%s: %llx done\n",
                    __func__, (uint64_t)VM_KERNEL_ADDRPERM(d));
        }
        /*
         * Let the caller know the bpf_d is closed
         */
        if (bpf_closed) {
                return 1;
        } else {
                return 0;
        }
}

/*
 * Start asynchronous timer, if necessary.
 * Must be called with bpf_mlock held.
 */
static void
bpf_start_timer(struct bpf_d *d)
{
        uint64_t deadline;
        struct timeval tv;

        if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) {
                tv.tv_sec = d->bd_rtout / hz;
                tv.tv_usec = (d->bd_rtout % hz) * tick;

                clock_interval_to_deadline(
                        (uint64_t)tv.tv_sec * USEC_PER_SEC + tv.tv_usec,
                        NSEC_PER_USEC, &deadline);
                /*
                 * The state is BPF_IDLE, so the timer hasn't
                 * been started yet, and hasn't gone off yet;
                 * there is no thread call scheduled, so this
                 * won't change the schedule.
                 *
                 * XXX - what if, by the time it gets entered,
                 * the deadline has already passed?
                 */
                thread_call_enter_delayed(d->bd_thread_call, deadline);
                d->bd_state = BPF_WAITING;
        }
}

/*
 * Cancel asynchronous timer.
 * Must be called with bpf_mlock held.
 */
static boolean_t
bpf_stop_timer(struct bpf_d *d)
{
        /*
         * If the timer has already gone off, this does nothing.
         * Our caller is expected to set d->bd_state to BPF_IDLE,
         * with the bpf_mlock, after we are called. bpf_timed_out()
         * also grabs bpf_mlock, so, if the timer has gone off and
         * bpf_timed_out() hasn't finished, it's waiting for the
         * lock; when this thread releases the lock, it will
         * find the state is BPF_IDLE, and just release the
         * lock and return.
         */
        return thread_call_cancel(d->bd_thread_call);
}

void
bpf_acquire_d(struct bpf_d *d)
{
        void *lr_saved =  __builtin_return_address(0);

        LCK_MTX_ASSERT(bpf_mlock, LCK_MTX_ASSERT_OWNED);

        d->bd_refcnt += 1;

        d->bd_ref_lr[d->bd_next_ref_lr] = lr_saved;
        d->bd_next_ref_lr = (d->bd_next_ref_lr + 1) % BPF_REF_HIST;
}

void
bpf_release_d(struct bpf_d *d)
{
        void *lr_saved =  __builtin_return_address(0);

        LCK_MTX_ASSERT(bpf_mlock, LCK_MTX_ASSERT_OWNED);

        if (d->bd_refcnt <= 0) {
                panic("%s: %p refcnt <= 0", __func__, d);
        }

        d->bd_refcnt -= 1;

        d->bd_unref_lr[d->bd_next_unref_lr] = lr_saved;
        d->bd_next_unref_lr = (d->bd_next_unref_lr + 1) % BPF_REF_HIST;

        if (d->bd_refcnt == 0) {
                /* Assert the device is detached */
                if ((d->bd_flags & BPF_DETACHED) == 0) {
                        panic("%s: %p BPF_DETACHED not set", __func__, d);
                }

                _FREE(d, M_DEVBUF);
        }
}

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

        lck_mtx_lock(bpf_mlock);
        if ((unsigned int) minor(dev) >= nbpfilter) {
                lck_mtx_unlock(bpf_mlock);
                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)] == NULL) {
                /* Reserve while opening */
                bpf_dtab[minor(dev)] = BPF_DEV_RESERVED;
        } else {
                lck_mtx_unlock(bpf_mlock);
                return EBUSY;
        }
        d = (struct bpf_d *)_MALLOC(sizeof(struct bpf_d), M_DEVBUF,
            M_WAIT | M_ZERO);
        if (d == NULL) {
                /* this really is a catastrophic failure */
                printf("bpfopen: malloc bpf_d failed\n");
                bpf_dtab[minor(dev)] = NULL;
                lck_mtx_unlock(bpf_mlock);
                return ENOMEM;
        }

        /* Mark "in use" and do most initialization. */
        bpf_acquire_d(d);
        d->bd_bufsize = bpf_bufsize;
        d->bd_sig = SIGIO;
        d->bd_seesent = 1;
        d->bd_oflags = flags;
        d->bd_state = BPF_IDLE;
        d->bd_traffic_class = SO_TC_BE;
        d->bd_flags |= BPF_DETACHED;
        if (bpf_wantpktap) {
                d->bd_flags |= BPF_WANT_PKTAP;
        } else {
                d->bd_flags &= ~BPF_WANT_PKTAP;
        }
        d->bd_thread_call = thread_call_allocate(bpf_timed_out, d);
        if (d->bd_thread_call == NULL) {
                printf("bpfopen: malloc thread call failed\n");
                bpf_dtab[minor(dev)] = NULL;
                bpf_release_d(d);
                lck_mtx_unlock(bpf_mlock);

                return ENOMEM;
        }
        d->bd_opened_by = p;
        uuid_generate(d->bd_uuid);

        bpf_dtab[minor(dev)] = d; /* Mark opened */
        lck_mtx_unlock(bpf_mlock);

        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)
{
        struct bpf_d *d;

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

        d = bpf_dtab[minor(dev)];
        if (d == NULL || d == BPF_DEV_RESERVED) {
                lck_mtx_unlock(bpf_mlock);
                return ENXIO;
        }

        /*
         * Other threads may call bpd_detachd() if we drop the bpf_mlock
         */
        d->bd_flags |= BPF_CLOSING;

        if (bpf_debug != 0) {
                printf("%s: %llx\n",
                    __func__, (uint64_t)VM_KERNEL_ADDRPERM(d));
        }

        bpf_dtab[minor(dev)] = BPF_DEV_RESERVED; /* Reserve while closing */

        /*
         * Deal with any in-progress timeouts.
         */
        switch (d->bd_state) {
        case BPF_IDLE:
                /*
                 * Not waiting for a timeout, and no timeout happened.
                 */
                break;

        case BPF_WAITING:
                /*
                 * Waiting for a timeout.
                 * Cancel any timer that has yet to go off,
                 * and mark the state as "closing".
                 * Then drop the lock to allow any timers that
                 * *have* gone off to run to completion, and wait
                 * for them to finish.
                 */
                if (!bpf_stop_timer(d)) {
                        /*
                         * There was no pending call, so the call must
                         * have been in progress. Wait for the call to
                         * complete; we have to drop the lock while
                         * waiting. to let the in-progrss call complete
                         */
                        d->bd_state = BPF_DRAINING;
                        while (d->bd_state == BPF_DRAINING) {
                                msleep((caddr_t)d, bpf_mlock, PRINET,
                                    "bpfdraining", NULL);
                        }
                }
                d->bd_state = BPF_IDLE;
                break;

        case BPF_TIMED_OUT:
                /*
                 * Timer went off, and the timeout routine finished.
                 */
                d->bd_state = BPF_IDLE;
                break;

        case BPF_DRAINING:
                /*
                 * Another thread is blocked on a close waiting for
                 * a timeout to finish.
                 * This "shouldn't happen", as the first thread to enter
                 * bpfclose() will set bpf_dtab[minor(dev)] to 1, and
                 * all subsequent threads should see that and fail with
                 * ENXIO.
                 */
                panic("Two threads blocked in a BPF close");
                break;
        }

        if (d->bd_bif) {
                bpf_detachd(d, 1);
        }
        selthreadclear(&d->bd_sel);
        thread_call_free(d->bd_thread_call);

        while (d->bd_hbuf_read != 0) {
                msleep((caddr_t)d, bpf_mlock, PRINET, "bpf_reading", NULL);
        }

        bpf_freed(d);

        /* Mark free in same context as bpfopen comes to check */
        bpf_dtab[minor(dev)] = NULL;                    /* Mark closed */

        bpf_release_d(d);

        lck_mtx_unlock(bpf_mlock);

        return 0;
}

#define BPF_SLEEP bpf_sleep

static int
bpf_sleep(struct bpf_d *d, int pri, const char *wmesg, int timo)
{
        u_int64_t abstime = 0;

        if (timo != 0) {
                clock_interval_to_deadline(timo, NSEC_PER_SEC / hz, &abstime);
        }

        return msleep1((caddr_t)d, bpf_mlock, pri, wmesg, abstime);
}

static void
bpf_finalize_pktap(struct bpf_hdr *hp, struct pktap_header *pktaphdr)
{
        if (pktaphdr->pth_flags & PTH_FLAG_V2_HDR) {
                struct pktap_v2_hdr *pktap_v2_hdr;

                pktap_v2_hdr = (struct pktap_v2_hdr *)pktaphdr;

                if (pktap_v2_hdr->pth_flags & PTH_FLAG_DELAY_PKTAP) {
                        pktap_v2_finalize_proc_info(pktap_v2_hdr);
                }
        } else {
                if (pktaphdr->pth_flags & PTH_FLAG_DELAY_PKTAP) {
                        pktap_finalize_proc_info(pktaphdr);
                }

                if (pktaphdr->pth_flags & PTH_FLAG_TSTAMP) {
                        hp->bh_tstamp.tv_sec = pktaphdr->pth_tstamp.tv_sec;
                        hp->bh_tstamp.tv_usec = pktaphdr->pth_tstamp.tv_usec;
                }
        }
}

/*
 * 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) \
        if (d->bd_hbuf_read != 0) \
                panic("rotating bpf buffers during read"); \
        (d)->bd_hbuf = (d)->bd_sbuf; \
        (d)->bd_hlen = (d)->bd_slen; \
        (d)->bd_hcnt = (d)->bd_scnt; \
        (d)->bd_sbuf = (d)->bd_fbuf; \
        (d)->bd_slen = 0; \
        (d)->bd_scnt = 0; \
        (d)->bd_fbuf = NULL;
/*
 *  bpfread - read next chunk of packets from buffers
 */
int
bpfread(dev_t dev, struct uio *uio, int ioflag)
{
        struct bpf_d *d;
        caddr_t hbuf;
        int timed_out, hbuf_len;
        int error;
        int flags;

        lck_mtx_lock(bpf_mlock);

        d = bpf_dtab[minor(dev)];
        if (d == NULL || d == BPF_DEV_RESERVED ||
            (d->bd_flags & BPF_CLOSING) != 0) {
                lck_mtx_unlock(bpf_mlock);
                return ENXIO;
        }

        bpf_acquire_d(d);

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

        if (d->bd_state == BPF_WAITING) {
                bpf_stop_timer(d);
        }

        timed_out = (d->bd_state == BPF_TIMED_OUT);
        d->bd_state = BPF_IDLE;

        while (d->bd_hbuf_read != 0) {
                msleep((caddr_t)d, bpf_mlock, PRINET, "bpf_reading", NULL);
        }

        if ((d->bd_flags & BPF_CLOSING) != 0) {
                bpf_release_d(d);
                lck_mtx_unlock(bpf_mlock);
                return ENXIO;
        }
        /*
         * 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 || timed_out || (ioflag & IO_NDELAY)) &&
                    d->bd_slen != 0) {
                        /*
                         * We're in immediate mode, or are reading
                         * in non-blocking mode, or a timer was
                         * started before the read (e.g., by select()
                         * or poll()) and has expired and 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) {
                        bpf_release_d(d);
                        lck_mtx_unlock(bpf_mlock);
                        return ENXIO;
                }
                if (ioflag & IO_NDELAY) {
                        bpf_release_d(d);
                        lck_mtx_unlock(bpf_mlock);
                        return EWOULDBLOCK;
                }
                error = BPF_SLEEP(d, PRINET | PCATCH, "bpf", d->bd_rtout);
                /*
                 * Make sure device is still opened
                 */
                if ((d->bd_flags & BPF_CLOSING) != 0) {
                        bpf_release_d(d);
                        lck_mtx_unlock(bpf_mlock);
                        return ENXIO;
                }

                while (d->bd_hbuf_read != 0) {
                        msleep((caddr_t)d, bpf_mlock, PRINET, "bpf_reading",
                            NULL);
                }

                if ((d->bd_flags & BPF_CLOSING) != 0) {
                        bpf_release_d(d);
                        lck_mtx_unlock(bpf_mlock);
                        return ENXIO;
                }

                if (error == EINTR || error == ERESTART) {
                        if (d->bd_hbuf != NULL) {
                                /*
                                 * Because we msleep, the hold buffer might
                                 * be filled when we wake up.  Avoid rotating
                                 * in this case.
                                 */
                                break;
                        }
                        if (d->bd_slen != 0) {
                                /*
                                 * Sometimes we may be interrupted often and
                                 * the sleep above will not timeout.
                                 * Regardless, we should rotate the buffers
                                 * if there's any new data pending and
                                 * return it.
                                 */
                                ROTATE_BUFFERS(d);
                                break;
                        }
                        bpf_release_d(d);
                        lck_mtx_unlock(bpf_mlock);
                        if (error == ERESTART) {
                                printf("%s: %llx ERESTART to EINTR\n",
                                    __func__, (uint64_t)VM_KERNEL_ADDRPERM(d));
                                error = EINTR;
                        }
                        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) {
                                bpf_release_d(d);
                                lck_mtx_unlock(bpf_mlock);
                                return 0;
                        }
                        ROTATE_BUFFERS(d);
                        break;
                }
        }
        /*
         * At this point, we know we have something in the hold slot.
         */

        /*
         * Set the hold buffer read. So we do not
         * rotate the buffers until the hold buffer
         * read is complete. Also to avoid issues resulting
         * from page faults during disk sleep (<rdar://problem/13436396>).
         */
        d->bd_hbuf_read = 1;
        hbuf = d->bd_hbuf;
        hbuf_len = d->bd_hlen;
        flags = d->bd_flags;
        lck_mtx_unlock(bpf_mlock);

#ifdef __APPLE__
        /*
         * Before we move data to userland, we fill out the extended
         * header fields.
         */
        if (flags & BPF_EXTENDED_HDR) {
                char *p;

                p = hbuf;
                while (p < hbuf + hbuf_len) {
                        struct bpf_hdr_ext *ehp;
                        uint32_t flowid;
                        struct so_procinfo soprocinfo;
                        int found = 0;

                        ehp = (struct bpf_hdr_ext *)(void *)p;
                        if ((flowid = ehp->bh_flowid) != 0) {
                                if (ehp->bh_proto == IPPROTO_TCP) {
                                        found = inp_findinpcb_procinfo(&tcbinfo,
                                            flowid, &soprocinfo);
                                } else if (ehp->bh_proto == IPPROTO_UDP) {
                                        found = inp_findinpcb_procinfo(&udbinfo,
                                            flowid, &soprocinfo);
                                }
                                if (found == 1) {
                                        ehp->bh_pid = soprocinfo.spi_pid;
                                        strlcpy(&ehp->bh_comm[0], &soprocinfo.spi_proc_name[0], sizeof(ehp->bh_comm));
                                }
                                ehp->bh_flowid = 0;
                        }

                        if (flags & BPF_FINALIZE_PKTAP) {
                                struct pktap_header *pktaphdr;

                                pktaphdr = (struct pktap_header *)(void *)
                                    (p + BPF_WORDALIGN(ehp->bh_hdrlen));

                                bpf_finalize_pktap((struct bpf_hdr *) ehp,
                                    pktaphdr);
                        }
                        p += BPF_WORDALIGN(ehp->bh_hdrlen + ehp->bh_caplen);
                }
        } else if (flags & BPF_FINALIZE_PKTAP) {
                char *p;

                p = hbuf;
                while (p < hbuf + hbuf_len) {
                        struct bpf_hdr *hp;
                        struct pktap_header *pktaphdr;

                        hp = (struct bpf_hdr *)(void *)p;
                        pktaphdr = (struct pktap_header *)(void *)
                            (p + BPF_WORDALIGN(hp->bh_hdrlen));

                        bpf_finalize_pktap(hp, pktaphdr);

                        p += BPF_WORDALIGN(hp->bh_hdrlen + hp->bh_caplen);
                }
        }
#endif

        /*
         * 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(hbuf, hbuf_len, UIO_READ, uio);

        lck_mtx_lock(bpf_mlock);
        /*
         * Make sure device is still opened
         */
        if ((d->bd_flags & BPF_CLOSING) != 0) {
                bpf_release_d(d);
                lck_mtx_unlock(bpf_mlock);
                return ENXIO;
        }

        d->bd_hbuf_read = 0;
        d->bd_fbuf = d->bd_hbuf;
        d->bd_hbuf = NULL;
        d->bd_hlen = 0;
        d->bd_hcnt = 0;
        wakeup((caddr_t)d);

        bpf_release_d(d);
        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)
{
        if (d->bd_state == BPF_WAITING) {
                bpf_stop_timer(d);
                d->bd_state = BPF_IDLE;
        }
        wakeup((caddr_t)d);
        if (d->bd_async && d->bd_sig && d->bd_sigio) {
                pgsigio(d->bd_sigio, d->bd_sig);
        }

        selwakeup(&d->bd_sel);
        if ((d->bd_flags & BPF_KNOTE)) {
                KNOTE(&d->bd_sel.si_note, 1);
        }
}

static void
bpf_timed_out(void *arg, __unused void *dummy)
{
        struct bpf_d *d = (struct bpf_d *)arg;

        lck_mtx_lock(bpf_mlock);
        if (d->bd_state == BPF_WAITING) {
                /*
                 * There's a select or kqueue waiting for this; if there's
                 * now stuff to read, wake it up.
                 */
                d->bd_state = BPF_TIMED_OUT;
                if (d->bd_slen != 0) {
                        bpf_wakeup(d);
                }
        } else if (d->bd_state == BPF_DRAINING) {
                /*
                 * A close is waiting for this to finish.
                 * Mark it as finished, and wake the close up.
                 */
                d->bd_state = BPF_IDLE;
                bpf_wakeup(d);
        }
        lck_mtx_unlock(bpf_mlock);
}

/* 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)
{
        struct bpf_d *d;
        struct ifnet *ifp;
        struct mbuf *m = NULL;
        int error;
        char              dst_buf[SOCKADDR_HDR_LEN + MAX_DATALINK_HDR_LEN];
        int datlen = 0;
        int bif_dlt;
        int bd_hdrcmplt;

        lck_mtx_lock(bpf_mlock);

        d = bpf_dtab[minor(dev)];
        if (d == NULL || d == BPF_DEV_RESERVED ||
            (d->bd_flags & BPF_CLOSING) != 0) {
                lck_mtx_unlock(bpf_mlock);
                return ENXIO;
        }

        bpf_acquire_d(d);

        if (d->bd_bif == 0) {
                bpf_release_d(d);
                lck_mtx_unlock(bpf_mlock);
                return ENXIO;
        }

        ifp = d->bd_bif->bif_ifp;

        if ((ifp->if_flags & IFF_UP) == 0) {
                bpf_release_d(d);
                lck_mtx_unlock(bpf_mlock);
                return ENETDOWN;
        }
        if (uio_resid(uio) == 0) {
                bpf_release_d(d);
                lck_mtx_unlock(bpf_mlock);
                return 0;
        }
        ((struct sockaddr *)dst_buf)->sa_len = sizeof(dst_buf);

        /*
         * fix for PR-6849527
         * geting variables onto stack before dropping lock for bpf_movein()
         */
        bif_dlt = (int)d->bd_bif->bif_dlt;
        bd_hdrcmplt  = d->bd_hdrcmplt;

        /* bpf_movein allocating mbufs; drop lock */
        lck_mtx_unlock(bpf_mlock);

        error = bpf_movein(uio, bif_dlt, &m,
            bd_hdrcmplt ? NULL : (struct sockaddr *)dst_buf,
            &datlen);

        /* take the lock again */
        lck_mtx_lock(bpf_mlock);
        if (error) {
                bpf_release_d(d);
                lck_mtx_unlock(bpf_mlock);
                return error;
        }

        /* verify the device is still open */
        if ((d->bd_flags & BPF_CLOSING) != 0) {
                bpf_release_d(d);
                lck_mtx_unlock(bpf_mlock);
                m_freem(m);
                return ENXIO;
        }

        if (d->bd_bif == NULL) {
                bpf_release_d(d);
                lck_mtx_unlock(bpf_mlock);
                m_free(m);
                return ENXIO;
        }

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

        bpf_set_packet_service_class(m, d->bd_traffic_class);

        lck_mtx_unlock(bpf_mlock);

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

        lck_mtx_lock(bpf_mlock);
        bpf_release_d(d);
        lck_mtx_unlock(bpf_mlock);

        return error;
}

/*
 * Reset a descriptor by flushing its packet buffer and clearing the
 * receive and drop counts.
 */
static void
reset_d(struct bpf_d *d)
{
        if (d->bd_hbuf_read != 0) {
                panic("resetting buffers during read");
        }

        if (d->bd_hbuf) {
                /* Free the hold buffer. */
                d->bd_fbuf = d->bd_hbuf;
                d->bd_hbuf = NULL;
        }
        d->bd_slen = 0;
        d->bd_hlen = 0;
        d->bd_scnt = 0;
        d->bd_hcnt = 0;
        d->bd_rcount = 0;
        d->bd_dcount = 0;
}

static struct bpf_d *
bpf_get_device_from_uuid(uuid_t uuid)
{
        unsigned int i;

        for (i = 0; i < nbpfilter; i++) {
                struct bpf_d *d = bpf_dtab[i];

                if (d == NULL || d == BPF_DEV_RESERVED ||
                    (d->bd_flags & BPF_CLOSING) != 0) {
                        continue;
                }
                if (uuid_compare(uuid, d->bd_uuid) == 0) {
                        return d;
                }
        }

        return NULL;
}

/*
 * The BIOCSETUP command "atomically" attach to the interface and
 * copy the buffer from another interface. This minimizes the risk
 * of missing packet because this is done while holding
 * the BPF global lock
 */
static int
bpf_setup(struct bpf_d *d_to, uuid_t uuid_from, ifnet_t ifp)
{
        struct bpf_d *d_from;
        int error = 0;

        LCK_MTX_ASSERT(bpf_mlock, LCK_MTX_ASSERT_OWNED);

        /*
         * Sanity checks
         */
        d_from = bpf_get_device_from_uuid(uuid_from);
        if (d_from == NULL) {
                error = ENOENT;
                os_log_info(OS_LOG_DEFAULT,
                    "%s: uuids not found error %d",
                    __func__, error);
                return error;
        }
        if (d_from->bd_opened_by != d_to->bd_opened_by) {
                error = EACCES;
                os_log_info(OS_LOG_DEFAULT,
                    "%s: processes not matching error %d",
                    __func__, error);
                return error;
        }

        /*
         * Prevent any read while copying
         */
        while (d_to->bd_hbuf_read != 0) {
                msleep((caddr_t)d_to, bpf_mlock, PRINET, __func__, NULL);
        }
        d_to->bd_hbuf_read = 1;

        while (d_from->bd_hbuf_read != 0) {
                msleep((caddr_t)d_from, bpf_mlock, PRINET, __func__, NULL);
        }
        d_from->bd_hbuf_read = 1;

        /*
         * Verify the devices have not been closed
         */
        if (d_to->bd_flags & BPF_CLOSING) {
                error = ENXIO;
                os_log_info(OS_LOG_DEFAULT,
                    "%s: d_to is closing error %d",
                    __func__, error);
                goto done;
        }
        if (d_from->bd_flags & BPF_CLOSING) {
                error = ENXIO;
                os_log_info(OS_LOG_DEFAULT,
                    "%s: d_from is closing error %d",
                    __func__, error);
                goto done;
        }

        /*
         * For now require the same buffer size
         */
        if (d_from->bd_bufsize != d_to->bd_bufsize) {
                error = EINVAL;
                os_log_info(OS_LOG_DEFAULT,
                    "%s: bufsizes not matching error %d",
                    __func__, error);
                goto done;
        }

        /*
         * Attach to the interface
         */
        error = bpf_setif(d_to, ifp, false, true);
        if (error != 0) {
                os_log_info(OS_LOG_DEFAULT,
                    "%s: bpf_setif() failed error %d",
                    __func__, error);
                goto done;
        }

        /*
         * Make sure the buffers are setup as expected by bpf_setif()
         */
        ASSERT(d_to->bd_hbuf == NULL);
        ASSERT(d_to->bd_sbuf != NULL);
        ASSERT(d_to->bd_fbuf != NULL);

        /*
         * Copy the buffers and update the pointers and counts
         */
        memcpy(d_to->bd_sbuf, d_from->bd_sbuf, d_from->bd_slen);
        d_to->bd_slen = d_from->bd_slen;
        d_to->bd_scnt = d_from->bd_scnt;

        if (d_from->bd_hbuf != NULL) {
                d_to->bd_hbuf = d_to->bd_fbuf;
                d_to->bd_fbuf = NULL;
                memcpy(d_to->bd_hbuf, d_from->bd_hbuf, d_from->bd_hlen);
        }
        d_to->bd_hlen = d_from->bd_hlen;
        d_to->bd_hcnt = d_from->bd_hcnt;

        if (bpf_debug > 0) {
                os_log_info(OS_LOG_DEFAULT,
                    "%s: done slen %u scnt %u hlen %u hcnt %u",
                    __func__, d_to->bd_slen, d_to->bd_scnt,
                    d_to->bd_hlen, d_to->bd_hcnt);
        }
done:
        d_from->bd_hbuf_read = 0;
        wakeup((caddr_t)d_from);

        d_to->bd_hbuf_read = 0;
        wakeup((caddr_t)d_to);

        return error;
}

/*
 *  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
 *  BIOCSETTC           Set traffic class.
 *  BIOCGETTC           Get traffic class.
 *  BIOCSEXTHDR         Set "extended header" flag
 *  BIOCSHEADDROP       Drop head of the buffer if user is not reading
 *  BIOCGHEADDROP       Get "head-drop" flag
 */
/* ARGSUSED */
int
bpfioctl(dev_t dev, u_long cmd, caddr_t addr, __unused int flags,
    struct proc *p)
{
        struct bpf_d *d;
        int error = 0;
        u_int int_arg;
        struct ifreq ifr;

        lck_mtx_lock(bpf_mlock);

        d = bpf_dtab[minor(dev)];
        if (d == NULL || d == BPF_DEV_RESERVED ||
            (d->bd_flags & BPF_CLOSING) != 0) {
                lck_mtx_unlock(bpf_mlock);
                return ENXIO;
        }

        bpf_acquire_d(d);

        if (d->bd_state == BPF_WAITING) {
                bpf_stop_timer(d);
        }
        d->bd_state = BPF_IDLE;

        switch (cmd) {
        default:
                error = EINVAL;
                break;

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

                n = d->bd_slen;
                if (d->bd_hbuf && d->bd_hbuf_read == 0) {
                        n += d->bd_hlen;
                }

                bcopy(&n, addr, sizeof(n));
                break;
        }

        case SIOCGIFADDR:               /* struct ifreq */
        {
                struct ifnet *ifp;

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

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

        /*
         * Set buffer length.
         */
        case BIOCSBLEN: {               /* u_int */
                u_int size;
                unsigned int maxbufsize = bpf_maxbufsize;

                /*
                 * Allow larger buffer in head drop mode to with the
                 * assumption the reading process may be low priority but
                 * is interested in the most recent traffic
                 */
                if (d->bd_headdrop != 0) {
                        maxbufsize = 2 * bpf_maxbufsize;
                }

                if (d->bd_bif != 0 || (d->bd_flags & BPF_DETACHING)) {
                        /*
                         * Interface already attached, unable to change buffers
                         */
                        error = EINVAL;
                        break;
                }
                bcopy(addr, &size, sizeof(size));

                if (size > maxbufsize) {
                        d->bd_bufsize = maxbufsize;

                        os_log_info(OS_LOG_DEFAULT,
                            "%s bufsize capped to %u from %u",
                            __func__, d->bd_bufsize, size);
                } else if (size < BPF_MINBUFSIZE) {
                        d->bd_bufsize = BPF_MINBUFSIZE;

                        os_log_info(OS_LOG_DEFAULT,
                            "%s bufsize bumped to %u from %u",
                            __func__, d->bd_bufsize, size);
                } else {
                        d->bd_bufsize = size;
                }

                /* It's a read/write ioctl */
                bcopy(&d->bd_bufsize, addr, sizeof(u_int));
                break;
        }
        /*
         * Set link layer read filter.
         */
        case BIOCSETF32:
        case BIOCSETFNR32: {            /* struct bpf_program32 */
                struct bpf_program32 prg32;

                bcopy(addr, &prg32, sizeof(prg32));
                error = bpf_setf(d, prg32.bf_len,
                    CAST_USER_ADDR_T(prg32.bf_insns), cmd);
                break;
        }

        case BIOCSETF64:
        case BIOCSETFNR64: {            /* struct bpf_program64 */
                struct bpf_program64 prg64;

                bcopy(addr, &prg64, sizeof(prg64));
                error = bpf_setf(d, prg64.bf_len, prg64.bf_insns, cmd);
                break;
        }

        /*
         * Flush read packet buffer.
         */
        case BIOCFLUSH:
                while (d->bd_hbuf_read != 0) {
                        msleep((caddr_t)d, bpf_mlock, PRINET, "bpf_reading",
                            NULL);
                }
                if ((d->bd_flags & BPF_CLOSING) != 0) {
                        error = ENXIO;
                        break;
                }
                reset_d(d);
                break;

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

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

        /*
         * Get a list of supported data link types.
         */
        case BIOCGDLTLIST:              /* struct bpf_dltlist */
                if (d->bd_bif == NULL) {
                        error = EINVAL;
                } else {
                        error = bpf_getdltlist(d, addr, p);
                }
                break;

        /*
         * Set data link type.
         */
        case BIOCSDLT:                  /* u_int */
                if (d->bd_bif == NULL) {
                        error = EINVAL;
                } else {
                        u_int dlt;

                        bcopy(addr, &dlt, sizeof(dlt));

                        if (dlt == DLT_PKTAP &&
                            !(d->bd_flags & BPF_WANT_PKTAP)) {
                                dlt = DLT_RAW;
                        }
                        error = bpf_setdlt(d, dlt);
                }
                break;

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

                        snprintf(((struct ifreq *)(void *)addr)->ifr_name,
                            sizeof(ifr.ifr_name), "%s", if_name(ifp));
                }
                break;

        /*
         * Set interface.
         */
        case BIOCSETIF: {               /* struct ifreq */
                ifnet_t ifp;

                bcopy(addr, &ifr, sizeof(ifr));
                ifr.ifr_name[IFNAMSIZ - 1] = '\0';
                ifp = ifunit(ifr.ifr_name);
                if (ifp == NULL) {
                        error = ENXIO;
                } else {
                        error = bpf_setif(d, ifp, true, false);
                }
                break;
        }

        /*
         * Set read timeout.
         */
        case BIOCSRTIMEOUT32: {         /* struct user32_timeval */
                struct user32_timeval _tv;
                struct timeval tv;

                bcopy(addr, &_tv, sizeof(_tv));
                tv.tv_sec  = _tv.tv_sec;
                tv.tv_usec = _tv.tv_usec;

                /*
                 * 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;
        }

        case BIOCSRTIMEOUT64: {         /* struct user64_timeval */
                struct user64_timeval _tv;
                struct timeval tv;

                bcopy(addr, &_tv, sizeof(_tv));
                tv.tv_sec  = _tv.tv_sec;
                tv.tv_usec = _tv.tv_usec;

                /*
                 * 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 BIOCGRTIMEOUT32: {         /* struct user32_timeval */
                struct user32_timeval tv;

                bzero(&tv, sizeof(tv));
                tv.tv_sec = d->bd_rtout / hz;
                tv.tv_usec = (d->bd_rtout % hz) * tick;
                bcopy(&tv, addr, sizeof(tv));
                break;
        }

        case BIOCGRTIMEOUT64: {         /* struct user64_timeval */
                struct user64_timeval tv;

                bzero(&tv, sizeof(tv));
                tv.tv_sec = d->bd_rtout / hz;
                tv.tv_usec = (d->bd_rtout % hz) * tick;
                bcopy(&tv, addr, sizeof(tv));
                break;
        }

        /*
         * Get packet stats.
         */
        case BIOCGSTATS: {              /* struct bpf_stat */
                struct bpf_stat bs;

                bzero(&bs, sizeof(bs));
                bs.bs_recv = d->bd_rcount;
                bs.bs_drop = d->bd_dcount;
                bcopy(&bs, addr, sizeof(bs));
                break;
        }

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

        case BIOCVERSION: {             /* struct bpf_version */
                struct bpf_version bv;

                bzero(&bv, sizeof(bv));
                bv.bv_major = BPF_MAJOR_VERSION;
                bv.bv_minor = BPF_MINOR_VERSION;
                bcopy(&bv, addr, sizeof(bv));
                break;
        }

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

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

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

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

        /*
         * Set traffic service class
         */
        case BIOCSETTC: {               /* int */
                int tc;

                bcopy(addr, &tc, sizeof(int));
                error = bpf_set_traffic_class(d, tc);
                break;
        }

        /*
         * Get traffic service class
         */
        case BIOCGETTC:                 /* int */
                bcopy(&d->bd_traffic_class, addr, sizeof(int));
                break;

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

        case FIOASYNC:          /* Send signal on receive packets; int */
                bcopy(addr, &d->bd_async, sizeof(int));
                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 */
                u_int sig;

                bcopy(addr, &sig, sizeof(u_int));

                if (sig >= NSIG) {
                        error = EINVAL;
                } else {
                        d->bd_sig = sig;
                }
                break;
        }
        case BIOCGRSIG:                 /* u_int */
                bcopy(&d->bd_sig, addr, sizeof(u_int));
                break;
#ifdef __APPLE__
        case BIOCSEXTHDR:               /* u_int */
                bcopy(addr, &int_arg, sizeof(int_arg));
                if (int_arg) {
                        d->bd_flags |= BPF_EXTENDED_HDR;
                } else {
                        d->bd_flags &= ~BPF_EXTENDED_HDR;
                }
                break;

        case BIOCGIFATTACHCOUNT: {              /* struct ifreq */
                ifnet_t ifp;
                struct bpf_if *bp;

                bcopy(addr, &ifr, sizeof(ifr));
                ifr.ifr_name[IFNAMSIZ - 1] = '\0';
                ifp = ifunit(ifr.ifr_name);
                if (ifp == NULL) {
                        error = ENXIO;
                        break;
                }
                ifr.ifr_intval = 0;
                for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) {
                        struct bpf_d *bpf_d;

                        if (bp->bif_ifp == NULL || bp->bif_ifp != ifp) {
                                continue;
                        }
                        for (bpf_d = bp->bif_dlist; bpf_d;
                            bpf_d = bpf_d->bd_next) {
                                ifr.ifr_intval += 1;
                        }
                }
                bcopy(&ifr, addr, sizeof(ifr));
                break;
        }
        case BIOCGWANTPKTAP:                    /* u_int */
                int_arg = d->bd_flags & BPF_WANT_PKTAP ? 1 : 0;
                bcopy(&int_arg, addr, sizeof(int_arg));
                break;

        case BIOCSWANTPKTAP:                    /* u_int */
                bcopy(addr, &int_arg, sizeof(int_arg));
                if (int_arg) {
                        d->bd_flags |= BPF_WANT_PKTAP;
                } else {
                        d->bd_flags &= ~BPF_WANT_PKTAP;
                }
                break;
#endif

        case BIOCSHEADDROP:
                bcopy(addr, &int_arg, sizeof(int_arg));
                d->bd_headdrop = int_arg ? 1 : 0;
                break;

        case BIOCGHEADDROP:
                bcopy(&d->bd_headdrop, addr, sizeof(int));
                break;

        case BIOCSTRUNCATE:
                bcopy(addr, &int_arg, sizeof(int_arg));
                if (int_arg) {
                        d->bd_flags |=  BPF_TRUNCATE;
                } else {
                        d->bd_flags &= ~BPF_TRUNCATE;
                }
                break;

        case BIOCGETUUID:
                bcopy(&d->bd_uuid, addr, sizeof(uuid_t));
                break;

        case BIOCSETUP: {
                struct bpf_setup_args bsa;
                ifnet_t ifp;

                bcopy(addr, &bsa, sizeof(struct bpf_setup_args));
                bsa.bsa_ifname[IFNAMSIZ - 1] = 0;
                ifp = ifunit(bsa.bsa_ifname);
                if (ifp == NULL) {
                        error = ENXIO;
                        os_log_info(OS_LOG_DEFAULT,
                            "%s: ifnet not found for %s error %d",
                            __func__, bsa.bsa_ifname, error);
                        break;
                }

                error = bpf_setup(d, bsa.bsa_uuid, ifp);
                break;
        }
        case BIOCSPKTHDRV2:
                bcopy(addr, &int_arg, sizeof(int_arg));
                if (int_arg != 0) {
                        d->bd_flags |= BPF_PKTHDRV2;
                } else {
                        d->bd_flags &= ~BPF_PKTHDRV2;
                }
                break;

        case BIOCGPKTHDRV2:
                int_arg = d->bd_flags & BPF_PKTHDRV2 ? 1 : 0;
                bcopy(&int_arg, addr, sizeof(int));
                break;
        }

        bpf_release_d(d);
        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, u_int bf_len, user_addr_t bf_insns,
    u_long cmd)
{
        struct bpf_insn *fcode, *old;
        u_int flen, size;

        while (d->bd_hbuf_read != 0) {
                msleep((caddr_t)d, bpf_mlock, PRINET, "bpf_reading", NULL);
        }

        if ((d->bd_flags & BPF_CLOSING) != 0) {
                return ENXIO;
        }

        old = d->bd_filter;
        if (bf_insns == USER_ADDR_NULL) {
                if (bf_len != 0) {
                        return EINVAL;
                }
                d->bd_filter = NULL;
                reset_d(d);
                if (old != 0) {
                        FREE(old, M_DEVBUF);
                }
                return 0;
        }
        flen = 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(bf_insns, (caddr_t)fcode, size) == 0 &&
            bpf_validate(fcode, (int)flen)) {
                d->bd_filter = fcode;

                if (cmd == BIOCSETF32 || cmd == BIOCSETF64) {
                        reset_d(d);
                }

                if (old != 0) {
                        FREE(old, M_DEVBUF);
                }

                return 0;
        }
        FREE(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, ifnet_t theywant, bool do_reset, bool has_hbuf_read)
{
        struct bpf_if *bp;
        int error;

        while (d->bd_hbuf_read != 0 && !has_hbuf_read) {
                msleep((caddr_t)d, bpf_mlock, PRINET, "bpf_reading", NULL);
        }

        if ((d->bd_flags & BPF_CLOSING) != 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;
                }
                /*
                 * Do not use DLT_PKTAP, unless requested explicitly
                 */
                if (bp->bif_dlt == DLT_PKTAP && !(d->bd_flags & BPF_WANT_PKTAP)) {
                        continue;
                }
                /*
                 * Skip the coprocessor interface
                 */
                if (!intcoproc_unrestricted && IFNET_IS_INTCOPROC(ifp)) {
                        continue;
                }
                /*
                 * We found the requested interface.
                 * Allocate the packet buffers.
                 */
                error = bpf_allocbufs(d);
                if (error != 0) {
                        return error;
                }
                /*
                 * Detach if attached to something else.
                 */
                if (bp != d->bd_bif) {
                        if (d->bd_bif != NULL) {
                                if (bpf_detachd(d, 0) != 0) {
                                        return ENXIO;
                                }
                        }
                        if (bpf_attachd(d, bp) != 0) {
                                return ENXIO;
                        }
                }
                if (do_reset) {
                        reset_d(d);
                }
                return 0;
        }
        /* Not found. */
        return ENXIO;
}

/*
 * Get a list of available data link type of the interface.
 */
static int
bpf_getdltlist(struct bpf_d *d, caddr_t addr, struct proc *p)
{
        u_int           n;
        int             error;
        struct ifnet    *ifp;
        struct bpf_if   *bp;
        user_addr_t     dlist;
        struct bpf_dltlist bfl;

        bcopy(addr, &bfl, sizeof(bfl));
        if (proc_is64bit(p)) {
                dlist = (user_addr_t)bfl.bfl_u.bflu_pad;
        } else {
                dlist = CAST_USER_ADDR_T(bfl.bfl_u.bflu_list);
        }

        ifp = d->bd_bif->bif_ifp;
        n = 0;
        error = 0;

        for (bp = bpf_iflist; bp; bp = bp->bif_next) {
                if (bp->bif_ifp != ifp) {
                        continue;
                }
                /*
                 * Do not use DLT_PKTAP, unless requested explicitly
                 */
                if (bp->bif_dlt == DLT_PKTAP && !(d->bd_flags & BPF_WANT_PKTAP)) {
                        continue;
                }
                if (dlist != USER_ADDR_NULL) {
                        if (n >= bfl.bfl_len) {
                                return ENOMEM;
                        }
                        error = copyout(&bp->bif_dlt, dlist,
                            sizeof(bp->bif_dlt));
                        if (error != 0) {
                                break;
                        }
                        dlist += sizeof(bp->bif_dlt);
                }
                n++;
        }
        bfl.bfl_len = n;
        bcopy(&bfl, addr, sizeof(bfl));

        return error;
}

/*
 * Set the data link type of a BPF instance.
 */
static int
bpf_setdlt(struct bpf_d *d, uint32_t dlt)
{
        int error, opromisc;
        struct ifnet *ifp;
        struct bpf_if *bp;

        if (d->bd_bif->bif_dlt == dlt) {
                return 0;
        }

        while (d->bd_hbuf_read != 0) {
                msleep((caddr_t)d, bpf_mlock, PRINET, "bpf_reading", NULL);
        }

        if ((d->bd_flags & BPF_CLOSING) != 0) {
                return ENXIO;
        }

        ifp = d->bd_bif->bif_ifp;
        for (bp = bpf_iflist; bp; bp = bp->bif_next) {
                if (bp->bif_ifp == ifp && bp->bif_dlt == dlt) {
                        /*
                         * Do not use DLT_PKTAP, unless requested explicitly
                         */
                        if (bp->bif_dlt == DLT_PKTAP &&
                            !(d->bd_flags & BPF_WANT_PKTAP)) {
                                continue;
                        }
                        break;
                }
        }
        if (bp != NULL) {
                opromisc = d->bd_promisc;
                if (bpf_detachd(d, 0) != 0) {
                        return ENXIO;
                }
                error = bpf_attachd(d, bp);
                if (error) {
                        printf("bpf_setdlt: bpf_attachd %s%d failed (%d)\n",
                            ifnet_name(bp->bif_ifp), ifnet_unit(bp->bif_ifp),
                            error);
                        return error;
                }
                reset_d(d);
                if (opromisc) {
                        lck_mtx_unlock(bpf_mlock);
                        error = ifnet_set_promiscuous(bp->bif_ifp, 1);
                        lck_mtx_lock(bpf_mlock);
                        if (error) {
                                printf("%s: ifpromisc %s%d failed (%d)\n",
                                    __func__, ifnet_name(bp->bif_ifp),
                                    ifnet_unit(bp->bif_ifp), error);
                        } else {
                                d->bd_promisc = 1;
                        }
                }
        }
        return bp == NULL ? EINVAL : 0;
}

static int
bpf_set_traffic_class(struct bpf_d *d, int tc)
{
        int error = 0;

        if (!SO_VALID_TC(tc)) {
                error = EINVAL;
        } else {
                d->bd_traffic_class = tc;
        }

        return error;
}

static void
bpf_set_packet_service_class(struct mbuf *m, int tc)
{
        if (!(m->m_flags & M_PKTHDR)) {
                return;
        }

        VERIFY(SO_VALID_TC(tc));
        (void) m_set_service_class(m, so_tc2msc(tc));
}

/*
 * Support for select()
 *
 * Return true iff the specific operation will not block indefinitely.
 * Otherwise, return false but make a note that a selwakeup() must be done.
 */
int
bpfselect(dev_t dev, int which, void * wql, struct proc *p)
{
        struct bpf_d *d;
        int ret = 0;

        lck_mtx_lock(bpf_mlock);

        d = bpf_dtab[minor(dev)];
        if (d == NULL || d == BPF_DEV_RESERVED ||
            (d->bd_flags & BPF_CLOSING) != 0) {
                lck_mtx_unlock(bpf_mlock);
                return ENXIO;
        }

        bpf_acquire_d(d);

        if (d->bd_bif == NULL) {
                bpf_release_d(d);
                lck_mtx_unlock(bpf_mlock);
                return ENXIO;
        }

        while (d->bd_hbuf_read != 0) {
                msleep((caddr_t)d, bpf_mlock, PRINET, "bpf_reading", NULL);
        }

        if ((d->bd_flags & BPF_CLOSING) != 0) {
                bpf_release_d(d);
                lck_mtx_unlock(bpf_mlock);
                return ENXIO;
        }

        switch (which) {
        case FREAD:
                if (d->bd_hlen != 0 ||
                    ((d->bd_immediate ||
                    d->bd_state == BPF_TIMED_OUT) && d->bd_slen != 0)) {
                        ret = 1;         /* read has data to return */
                } else {
                        /*
                         * Read has no data to return.
                         * Make the select wait, and start a timer if
                         * necessary.
                         */
                        selrecord(p, &d->bd_sel, wql);
                        bpf_start_timer(d);
                }
                break;

        case FWRITE:
                /* can't determine whether a write would block */
                ret = 1;
                break;
        }

        bpf_release_d(d);
        lck_mtx_unlock(bpf_mlock);

        return ret;
}

/*
 * Support for kevent() system call.  Register EVFILT_READ filters and
 * reject all others.
 */
int bpfkqfilter(dev_t dev, struct knote *kn);
static void filt_bpfdetach(struct knote *);
static int filt_bpfread(struct knote *, long);
static int filt_bpftouch(struct knote *kn, struct kevent_qos_s *kev);
static int filt_bpfprocess(struct knote *kn, struct kevent_qos_s *kev);

SECURITY_READ_ONLY_EARLY(struct filterops) bpfread_filtops = {
        .f_isfd = 1,
        .f_detach = filt_bpfdetach,
        .f_event = filt_bpfread,
        .f_touch = filt_bpftouch,
        .f_process = filt_bpfprocess,
};

static int
filt_bpfread_common(struct knote *kn, struct kevent_qos_s *kev, struct bpf_d *d)
{
        int ready = 0;
        int64_t data = 0;

        if (d->bd_immediate) {
                /*
                 * If there's data in the hold buffer, it's the
                 * amount of data a read will return.
                 *
                 * If there's no data in the hold buffer, but
                 * there's data in the store buffer, a read will
                 * immediately rotate the store buffer to the
                 * hold buffer, the amount of data in the store
                 * buffer is the amount of data a read will
                 * return.
                 *
                 * If there's no data in either buffer, we're not
                 * ready to read.
                 */
                data = (d->bd_hlen == 0 || d->bd_hbuf_read != 0 ?
                    d->bd_slen : d->bd_hlen);
                int64_t lowwat = knote_low_watermark(kn);
                if (lowwat > d->bd_bufsize) {
                        lowwat = d->bd_bufsize;
                }
                ready = (data >= lowwat);
        } else {
                /*
                 * If there's data in the hold buffer, it's the
                 * amount of data a read will return.
                 *
                 * If there's no data in the hold buffer, but
                 * there's data in the store buffer, if the
                 * timer has expired a read will immediately
                 * rotate the store buffer to the hold buffer,
                 * so the amount of data in the store buffer is
                 * the amount of data a read will return.
                 *
                 * If there's no data in either buffer, or there's
                 * no data in the hold buffer and the timer hasn't
                 * expired, we're not ready to read.
                 */
                data = ((d->bd_hlen == 0 || d->bd_hbuf_read != 0) &&
                    d->bd_state == BPF_TIMED_OUT ? d->bd_slen : d->bd_hlen);
                ready = (data > 0);
        }
        if (!ready) {
                bpf_start_timer(d);
        } else if (kev) {
                knote_fill_kevent(kn, kev, data);
        }

        return ready;
}

int
bpfkqfilter(dev_t dev, struct knote *kn)
{
        struct bpf_d *d;
        int res;

        /*
         * Is this device a bpf?
         */
        if (major(dev) != CDEV_MAJOR || kn->kn_filter != EVFILT_READ) {
                knote_set_error(kn, EINVAL);
                return 0;
        }

        lck_mtx_lock(bpf_mlock);

        d = bpf_dtab[minor(dev)];

        if (d == NULL || d == BPF_DEV_RESERVED ||
            (d->bd_flags & BPF_CLOSING) != 0 ||
            d->bd_bif == NULL) {
                lck_mtx_unlock(bpf_mlock);
                knote_set_error(kn, ENXIO);
                return 0;
        }

        kn->kn_hook = d;
        kn->kn_filtid = EVFILTID_BPFREAD;
        KNOTE_ATTACH(&d->bd_sel.si_note, kn);
        d->bd_flags |= BPF_KNOTE;

        /* capture the current state */
        res = filt_bpfread_common(kn, NULL, d);

        lck_mtx_unlock(bpf_mlock);

        return res;
}

static void
filt_bpfdetach(struct knote *kn)
{
        struct bpf_d *d = (struct bpf_d *)kn->kn_hook;

        lck_mtx_lock(bpf_mlock);
        if (d->bd_flags & BPF_KNOTE) {
                KNOTE_DETACH(&d->bd_sel.si_note, kn);
                d->bd_flags &= ~BPF_KNOTE;
        }
        lck_mtx_unlock(bpf_mlock);
}

static int
filt_bpfread(struct knote *kn, long hint)
{
#pragma unused(hint)
        struct bpf_d *d = (struct bpf_d *)kn->kn_hook;

        return filt_bpfread_common(kn, NULL, d);
}

static int
filt_bpftouch(struct knote *kn, struct kevent_qos_s *kev)
{
        struct bpf_d *d = (struct bpf_d *)kn->kn_hook;
        int res;

        lck_mtx_lock(bpf_mlock);

        /* save off the lowat threshold and flag */
        kn->kn_sdata = kev->data;
        kn->kn_sfflags = kev->fflags;

        /* output data will be re-generated here */
        res = filt_bpfread_common(kn, NULL, d);

        lck_mtx_unlock(bpf_mlock);

        return res;
}

static int
filt_bpfprocess(struct knote *kn, struct kevent_qos_s *kev)
{
        struct bpf_d *d = (struct bpf_d *)kn->kn_hook;
        int res;

        lck_mtx_lock(bpf_mlock);
        res = filt_bpfread_common(kn, kev, d);
        lck_mtx_unlock(bpf_mlock);

        return res;
}

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

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

static inline void
bpf_tap_imp(
        ifnet_t         ifp,
        u_int32_t       dlt,
        struct bpf_packet *bpf_pkt,
        int             outbound)
{
        struct bpf_d    *d;
        u_int slen;
        struct bpf_if *bp;

        /*
         * It's possible that we get here after the bpf descriptor has been
         * detached from the interface; in such a case we simply return.
         * Lock ordering is important since we can be called asynchronously
         * (from IOKit) to process an inbound packet; when that happens
         * we would have been holding its "gateLock" and will be acquiring
         * "bpf_mlock" upon entering this routine.  Due to that, we release
         * "bpf_mlock" prior to calling ifnet_set_promiscuous (which will
         * acquire "gateLock" in the IOKit), in order to avoid a deadlock
         * when a ifnet_set_promiscuous request simultaneously collides with
         * an inbound packet being passed into the tap callback.
         */
        lck_mtx_lock(bpf_mlock);
        if (ifp->if_bpf == NULL) {
                lck_mtx_unlock(bpf_mlock);
                return;
        }
        for (bp = ifp->if_bpf; bp != NULL; bp = bp->bif_next) {
                if (bp->bif_ifp != ifp) {
                        /* wrong interface */
                        bp = NULL;
                        break;
                }
                if (dlt == 0 || bp->bif_dlt == dlt) {
                        /* tapping default DLT or DLT matches */
                        break;
                }
        }
        if (bp == NULL) {
                goto done;
        }
        for (d = bp->bif_dlist; d; d = d->bd_next) {
                struct bpf_packet *bpf_pkt_saved = bpf_pkt;
                struct bpf_packet bpf_pkt_tmp;
                struct pktap_header_buffer bpfp_header_tmp;

                if (outbound && !d->bd_seesent) {
                        continue;
                }

                ++d->bd_rcount;
                slen = bpf_filter(d->bd_filter, (u_char *)bpf_pkt,
                    bpf_pkt->bpfp_total_length, 0);
                if (bp->bif_ifp->if_type == IFT_PKTAP &&
                    bp->bif_dlt == DLT_PKTAP) {
                        /*
                         * Need to copy the bpf_pkt because the conversion
                         * to v2 pktap header modifies the content of the
                         * bpfp_header
                         */
                        if ((d->bd_flags & BPF_PKTHDRV2) &&
                            bpf_pkt->bpfp_header_length <= sizeof(bpfp_header_tmp)) {
                                bpf_pkt_tmp = *bpf_pkt;

                                bpf_pkt = &bpf_pkt_tmp;

                                memcpy(&bpfp_header_tmp, bpf_pkt->bpfp_header,
                                    bpf_pkt->bpfp_header_length);

                                bpf_pkt->bpfp_header = &bpfp_header_tmp;

                                convert_to_pktap_header_to_v2(bpf_pkt,
                                    !!(d->bd_flags & BPF_TRUNCATE));
                        }

                        if (d->bd_flags & BPF_TRUNCATE) {
                                slen = min(slen,
                                    get_pkt_trunc_len((u_char *)bpf_pkt,
                                    bpf_pkt->bpfp_total_length));
                        }
                }
                if (slen != 0) {
                        catchpacket(d, bpf_pkt, slen, outbound);
                }
                bpf_pkt = bpf_pkt_saved;
        }

done:
        lck_mtx_unlock(bpf_mlock);
}

static inline void
bpf_tap_mbuf(
        ifnet_t         ifp,
        u_int32_t       dlt,
        mbuf_t          m,
        void*           hdr,
        size_t          hlen,
        int             outbound)
{
        struct bpf_packet bpf_pkt;
        struct mbuf *m0;

        if (ifp->if_bpf == NULL) {
                /* quickly check without taking lock */
                return;
        }
        bpf_pkt.bpfp_type = BPF_PACKET_TYPE_MBUF;
        bpf_pkt.bpfp_mbuf = m;
        bpf_pkt.bpfp_total_length = 0;
        for (m0 = m; m0 != NULL; m0 = m0->m_next) {
                bpf_pkt.bpfp_total_length += m0->m_len;
        }
        bpf_pkt.bpfp_header = hdr;
        if (hdr != NULL) {
                bpf_pkt.bpfp_total_length += hlen;
                bpf_pkt.bpfp_header_length = hlen;
        } else {
                bpf_pkt.bpfp_header_length = 0;
        }
        bpf_tap_imp(ifp, dlt, &bpf_pkt, outbound);
}

void
bpf_tap_out(
        ifnet_t         ifp,
        u_int32_t       dlt,
        mbuf_t          m,
        void*           hdr,
        size_t          hlen)
{
        bpf_tap_mbuf(ifp, dlt, m, hdr, hlen, 1);
}

void
bpf_tap_in(
        ifnet_t         ifp,
        u_int32_t       dlt,
        mbuf_t          m,
        void*           hdr,
        size_t          hlen)
{
        bpf_tap_mbuf(ifp, dlt, m, hdr, hlen, 0);
}

/* Callback registered with Ethernet driver. */
static int
bpf_tap_callback(struct ifnet *ifp, struct mbuf *m)
{
        bpf_tap_mbuf(ifp, 0, m, NULL, 0, mbuf_pkthdr_rcvif(m) == NULL);

        return 0;
}


static errno_t
bpf_copydata(struct bpf_packet *pkt, size_t off, size_t len, void* out_data)
{
        errno_t err = 0;
        if (pkt->bpfp_type == BPF_PACKET_TYPE_MBUF) {
                err = mbuf_copydata(pkt->bpfp_mbuf, off, len, out_data);
        } else {
                err = EINVAL;
        }

        return err;
}

static void
copy_bpf_packet(struct bpf_packet * pkt, void * dst, size_t len)
{
        /* copy the optional header */
        if (pkt->bpfp_header_length != 0) {
                size_t  count = min(len, pkt->bpfp_header_length);
                bcopy(pkt->bpfp_header, dst, count);
                len -= count;
                dst += count;
        }
        if (len == 0) {
                /* nothing past the header */
                return;
        }
        /* copy the packet */
        switch (pkt->bpfp_type) {
        case BPF_PACKET_TYPE_MBUF:
                bpf_mcopy(pkt->bpfp_mbuf, dst, len);
                break;
        default:
                break;
        }
}

static uint16_t
get_esp_trunc_len(__unused struct bpf_packet *pkt, __unused uint16_t off,
    const uint16_t remaining_caplen)
{
        /*
         * For some reason tcpdump expects to have one byte beyond the ESP header
         */
        uint16_t trunc_len = ESP_HDR_SIZE + 1;

        if (trunc_len > remaining_caplen) {
                return remaining_caplen;
        }

        return trunc_len;
}

static uint16_t
get_isakmp_trunc_len(__unused struct bpf_packet *pkt, __unused uint16_t off,
    const uint16_t remaining_caplen)
{
        /*
         * Include the payload generic header
         */
        uint16_t trunc_len = ISAKMP_HDR_SIZE;

        if (trunc_len > remaining_caplen) {
                return remaining_caplen;
        }

        return trunc_len;
}

static uint16_t
get_isakmp_natt_trunc_len(struct bpf_packet *pkt, uint16_t off,
    const uint16_t remaining_caplen)
{
        int err = 0;
        uint16_t trunc_len = 0;
        char payload[remaining_caplen];

        err = bpf_copydata(pkt, off, remaining_caplen, payload);
        if (err != 0) {
                return remaining_caplen;
        }
        /*
         * They are three cases:
         * - IKE: payload start with 4 bytes header set to zero before ISAKMP header
         * - keep alive: 1 byte payload
         * - otherwise it's ESP
         */
        if (remaining_caplen >= 4 &&
            payload[0] == 0 && payload[1] == 0 &&
            payload[2] == 0 && payload[3] == 0) {
                trunc_len = 4 + get_isakmp_trunc_len(pkt, off + 4, remaining_caplen - 4);
        } else if (remaining_caplen == 1) {
                trunc_len = 1;
        } else {
                trunc_len = get_esp_trunc_len(pkt, off, remaining_caplen);
        }

        if (trunc_len > remaining_caplen) {
                return remaining_caplen;
        }

        return trunc_len;
}

static uint16_t
get_udp_trunc_len(struct bpf_packet *pkt, uint16_t off, const uint16_t remaining_caplen)
{
        int err = 0;
        uint16_t trunc_len = sizeof(struct udphdr); /* By default no UDP payload */

        if (trunc_len >= remaining_caplen) {
                return remaining_caplen;
        }

        struct udphdr udphdr;
        err = bpf_copydata(pkt, off, sizeof(struct udphdr), &udphdr);
        if (err != 0) {
                return remaining_caplen;
        }

        u_short sport, dport;

        sport = EXTRACT_SHORT(&udphdr.uh_sport);
        dport = EXTRACT_SHORT(&udphdr.uh_dport);

        if (dport == PORT_DNS || sport == PORT_DNS) {
                /*
                 * Full UDP payload for DNS
                 */
                trunc_len = remaining_caplen;
        } else if ((sport == PORT_BOOTPS && dport == PORT_BOOTPC) ||
            (sport == PORT_BOOTPC && dport == PORT_BOOTPS)) {
                /*
                 * Full UDP payload for BOOTP and DHCP
                 */
                trunc_len = remaining_caplen;
        } else if (dport == PORT_ISAKMP && sport == PORT_ISAKMP) {
                /*
                 * Return the ISAKMP header
                 */
                trunc_len += get_isakmp_trunc_len(pkt, off + sizeof(struct udphdr),
                    remaining_caplen - sizeof(struct udphdr));
        } else if (dport == PORT_ISAKMP_NATT && sport == PORT_ISAKMP_NATT) {
                trunc_len += get_isakmp_natt_trunc_len(pkt, off + sizeof(struct udphdr),
                    remaining_caplen - sizeof(struct udphdr));
        }
        if (trunc_len >= remaining_caplen) {
                return remaining_caplen;
        }

        return trunc_len;
}

static uint16_t
get_tcp_trunc_len(struct bpf_packet *pkt, uint16_t off, const uint16_t remaining_caplen)
{
        int err = 0;
        uint16_t trunc_len = sizeof(struct tcphdr); /* By default no TCP payload */
        if (trunc_len >= remaining_caplen) {
                return remaining_caplen;
        }

        struct tcphdr tcphdr;
        err = bpf_copydata(pkt, off, sizeof(struct tcphdr), &tcphdr);
        if (err != 0) {
                return remaining_caplen;
        }

        u_short sport, dport;
        sport = EXTRACT_SHORT(&tcphdr.th_sport);
        dport = EXTRACT_SHORT(&tcphdr.th_dport);

        if (dport == PORT_DNS || sport == PORT_DNS) {
                /*
                 * Full TCP payload  for DNS
                 */
                trunc_len = remaining_caplen;
        } else {
                trunc_len = tcphdr.th_off << 2;
        }
        if (trunc_len >= remaining_caplen) {
                return remaining_caplen;
        }

        return trunc_len;
}

static uint16_t
get_proto_trunc_len(uint8_t proto, struct bpf_packet *pkt, uint16_t off, const uint16_t remaining_caplen)
{
        uint16_t trunc_len;

        switch (proto) {
        case IPPROTO_ICMP: {
                /*
                 * Full IMCP payload
                 */
                trunc_len = remaining_caplen;
                break;
        }
        case IPPROTO_ICMPV6: {
                /*
                 * Full IMCPV6 payload
                 */
                trunc_len = remaining_caplen;
                break;
        }
        case IPPROTO_IGMP: {
                /*
                 * Full IGMP payload
                 */
                trunc_len = remaining_caplen;
                break;
        }
        case IPPROTO_UDP: {
                trunc_len = get_udp_trunc_len(pkt, off, remaining_caplen);
                break;
        }
        case IPPROTO_TCP: {
                trunc_len = get_tcp_trunc_len(pkt, off, remaining_caplen);
                break;
        }
        case IPPROTO_ESP: {
                trunc_len = get_esp_trunc_len(pkt, off, remaining_caplen);
                break;
        }
        default: {
                /*
                 * By default we only include the IP header
                 */
                trunc_len = 0;
                break;
        }
        }
        if (trunc_len >= remaining_caplen) {
                return remaining_caplen;
        }

        return trunc_len;
}

static uint16_t
get_ip_trunc_len(struct bpf_packet *pkt, uint16_t off, const uint16_t remaining_caplen)
{
        int err = 0;
        uint16_t iplen = sizeof(struct ip);
        if (iplen >= remaining_caplen) {
                return remaining_caplen;
        }

        struct ip iphdr;
        err =  bpf_copydata(pkt, off, sizeof(struct ip), &iphdr);
        if (err != 0) {
                return remaining_caplen;
        }

        uint8_t proto = 0;

        iplen = iphdr.ip_hl << 2;
        if (iplen >= remaining_caplen) {
                return remaining_caplen;
        }

        proto = iphdr.ip_p;
        iplen += get_proto_trunc_len(proto, pkt, off + iplen, remaining_caplen - iplen);

        if (iplen >= remaining_caplen) {
                return remaining_caplen;
        }

        return iplen;
}

static uint16_t
get_ip6_trunc_len(struct bpf_packet *pkt, uint16_t off, const uint16_t remaining_caplen)
{
        int err = 0;
        uint16_t iplen = sizeof(struct ip6_hdr);
        if (iplen >= remaining_caplen) {
                return remaining_caplen;
        }

        struct ip6_hdr ip6hdr;
        err = bpf_copydata(pkt, off, sizeof(struct ip6_hdr), &ip6hdr);
        if (err != 0) {
                return remaining_caplen;
        }

        uint8_t proto = 0;

        /*
         * TBD: process the extension headers
         */
        proto = ip6hdr.ip6_nxt;
        iplen += get_proto_trunc_len(proto, pkt, off + iplen, remaining_caplen - iplen);

        if (iplen >= remaining_caplen) {
                return remaining_caplen;
        }

        return iplen;
}

static uint16_t
get_ether_trunc_len(struct bpf_packet *pkt, int off, const uint16_t remaining_caplen)
{
        int err = 0;
        uint16_t ethlen = sizeof(struct ether_header);
        if (ethlen >= remaining_caplen) {
                return remaining_caplen;
        }

        struct ether_header eh;
        u_short type;
        err = bpf_copydata(pkt, off, sizeof(struct ether_header), &eh);
        if (err != 0) {
                return remaining_caplen;
        }

        type = EXTRACT_SHORT(&eh.ether_type);
        /* Include full ARP */
        if (type == ETHERTYPE_ARP) {
                ethlen = remaining_caplen;
        } else if (type != ETHERTYPE_IP && type != ETHERTYPE_IPV6) {
                ethlen = min(BPF_MIN_PKT_SIZE, remaining_caplen);
        } else {
                if (type == ETHERTYPE_IP) {
                        ethlen += get_ip_trunc_len(pkt, sizeof(struct ether_header),
                            remaining_caplen);
                } else if (type == ETHERTYPE_IPV6) {
                        ethlen += get_ip6_trunc_len(pkt, sizeof(struct ether_header),
                            remaining_caplen);
                }
        }
        return ethlen;
}

static uint32_t
get_pkt_trunc_len(u_char *p, u_int len)
{
        struct bpf_packet *pkt = (struct bpf_packet *)(void *) p;
        struct pktap_header *pktap = (struct pktap_header *) (pkt->bpfp_header);
        uint32_t out_pkt_len = 0, tlen = 0;
        /*
         * pktap->pth_frame_pre_length is L2 header length and accounts
         * for both pre and pre_adjust.
         * pktap->pth_length is sizeof(pktap_header) (excl the pre/pre_adjust)
         * pkt->bpfp_header_length is (pktap->pth_length + pre_adjust)
         * pre is the offset to the L3 header after the bpfp_header, or length
         * of L2 header after bpfp_header, if present.
         */
        int32_t pre = pktap->pth_frame_pre_length -
            (pkt->bpfp_header_length - pktap->pth_length);

        /* Length of the input packet starting from  L3 header */
        uint32_t in_pkt_len = len - pkt->bpfp_header_length - pre;
        if (pktap->pth_protocol_family == AF_INET ||
            pktap->pth_protocol_family == AF_INET6) {
                /* Contains L2 header */
                if (pre > 0) {
                        if (pre < (int32_t)sizeof(struct ether_header)) {
                                goto too_short;
                        }

                        out_pkt_len = get_ether_trunc_len(pkt, 0, in_pkt_len);
                } else if (pre == 0) {
                        if (pktap->pth_protocol_family == AF_INET) {
                                out_pkt_len = get_ip_trunc_len(pkt, pre, in_pkt_len);
                        } else if (pktap->pth_protocol_family == AF_INET6) {
                                out_pkt_len = get_ip6_trunc_len(pkt, pre, in_pkt_len);
                        }
                } else {
                        /* Ideally pre should be >= 0. This is an exception */
                        out_pkt_len = min(BPF_MIN_PKT_SIZE, in_pkt_len);
                }
        } else {
                if (pktap->pth_iftype == IFT_ETHER) {
                        if (in_pkt_len < sizeof(struct ether_header)) {
                                goto too_short;
                        }
                        /* At most include the Ethernet header and 16 bytes */
                        out_pkt_len = MIN(sizeof(struct ether_header) + 16,
                            in_pkt_len);
                } else {
                        /*
                         * For unknown protocols include at most 16 bytes
                         */
                        out_pkt_len = MIN(16, in_pkt_len);
                }
        }
done:
        tlen = pkt->bpfp_header_length + out_pkt_len + pre;
        return tlen;
too_short:
        out_pkt_len = in_pkt_len;
        goto done;
}

/*
 * 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.
 */
static void
catchpacket(struct bpf_d *d, struct bpf_packet * pkt,
    u_int snaplen, int outbound)
{
        struct bpf_hdr *hp;
        struct bpf_hdr_ext *ehp;
        int totlen, curlen;
        int hdrlen, caplen;
        int do_wakeup = 0;
        u_char *payload;
        struct timeval tv;

        hdrlen = (d->bd_flags & BPF_EXTENDED_HDR) ? d->bd_bif->bif_exthdrlen :
            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, pkt->bpfp_total_length);
        if (totlen > d->bd_bufsize) {
                totlen = d->bd_bufsize;
        }

        if (hdrlen > totlen) {
                return;
        }

        /*
         * 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.
                 *
                 * We cannot rotate buffers if a read is in progress
                 * so drop the packet
                 */
                if (d->bd_hbuf_read != 0) {
                        ++d->bd_dcount;
                        return;
                }

                if (d->bd_fbuf == NULL) {
                        if (d->bd_headdrop == 0) {
                                /*
                                 * We haven't completed the previous read yet,
                                 * so drop the packet.
                                 */
                                ++d->bd_dcount;
                                return;
                        }
                        /*
                         * Drop the hold buffer as it contains older packets
                         */
                        d->bd_dcount += d->bd_hcnt;
                        d->bd_fbuf = d->bd_hbuf;
                        ROTATE_BUFFERS(d);
                } else {
                        ROTATE_BUFFERS(d);
                }
                do_wakeup = 1;
                curlen = 0;
        } else if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT) {
                /*
                 * Immediate mode is set, or the read timeout has
                 * already expired during a select call. A packet
                 * arrived, so the reader should be woken up.
                 */
                do_wakeup = 1;
        }

        /*
         * Append the bpf header.
         */
        microtime(&tv);
        if (d->bd_flags & BPF_EXTENDED_HDR) {
                struct mbuf *m;

                m = (pkt->bpfp_type == BPF_PACKET_TYPE_MBUF)
                    ? pkt->bpfp_mbuf : NULL;
                ehp = (struct bpf_hdr_ext *)(void *)(d->bd_sbuf + curlen);
                memset(ehp, 0, sizeof(*ehp));
                ehp->bh_tstamp.tv_sec = tv.tv_sec;
                ehp->bh_tstamp.tv_usec = tv.tv_usec;

                ehp->bh_datalen = pkt->bpfp_total_length;
                ehp->bh_hdrlen = hdrlen;
                caplen = ehp->bh_caplen = totlen - hdrlen;
                if (m == NULL) {
                        if (outbound) {
                                ehp->bh_flags |= BPF_HDR_EXT_FLAGS_DIR_OUT;
                        } else {
                                ehp->bh_flags |= BPF_HDR_EXT_FLAGS_DIR_IN;
                        }
                } else if (outbound) {
                        ehp->bh_flags |= BPF_HDR_EXT_FLAGS_DIR_OUT;

                        /* only do lookups on non-raw INPCB */
                        if ((m->m_pkthdr.pkt_flags & (PKTF_FLOW_ID |
                            PKTF_FLOW_LOCALSRC | PKTF_FLOW_RAWSOCK)) ==
                            (PKTF_FLOW_ID | PKTF_FLOW_LOCALSRC) &&
                            m->m_pkthdr.pkt_flowsrc == FLOWSRC_INPCB) {
                                ehp->bh_flowid = m->m_pkthdr.pkt_flowid;
                                ehp->bh_proto = m->m_pkthdr.pkt_proto;
                        }
                        ehp->bh_svc = so_svc2tc(m->m_pkthdr.pkt_svc);
                        if (m->m_pkthdr.pkt_flags & PKTF_TCP_REXMT) {
                                ehp->bh_pktflags |= BPF_PKTFLAGS_TCP_REXMT;
                        }
                        if (m->m_pkthdr.pkt_flags & PKTF_START_SEQ) {
                                ehp->bh_pktflags |= BPF_PKTFLAGS_START_SEQ;
                        }
                        if (m->m_pkthdr.pkt_flags & PKTF_LAST_PKT) {
                                ehp->bh_pktflags |= BPF_PKTFLAGS_LAST_PKT;
                        }
                        if (m->m_pkthdr.pkt_flags & PKTF_VALID_UNSENT_DATA) {
                                ehp->bh_unsent_bytes =
                                    m->m_pkthdr.bufstatus_if;
                                ehp->bh_unsent_snd =
                                    m->m_pkthdr.bufstatus_sndbuf;
                        }
                } else {
                        ehp->bh_flags |= BPF_HDR_EXT_FLAGS_DIR_IN;
                }
                payload = (u_char *)ehp + hdrlen;
        } else {
                hp = (struct bpf_hdr *)(void *)(d->bd_sbuf + curlen);
                hp->bh_tstamp.tv_sec = tv.tv_sec;
                hp->bh_tstamp.tv_usec = tv.tv_usec;
                hp->bh_datalen = pkt->bpfp_total_length;
                hp->bh_hdrlen = hdrlen;
                caplen = hp->bh_caplen = totlen - hdrlen;
                payload = (u_char *)hp + hdrlen;
        }
        /*
         * Copy the packet data into the store buffer and update its length.
         */
        copy_bpf_packet(pkt, payload, caplen);
        d->bd_slen = curlen + totlen;
        d->bd_scnt += 1;

        if (do_wakeup) {
                bpf_wakeup(d);
        }
}

/*
 * Initialize all nonzero fields of a descriptor.
 */
static int
bpf_allocbufs(struct bpf_d *d)
{
        if (d->bd_sbuf != NULL) {
                FREE(d->bd_sbuf, M_DEVBUF);
                d->bd_sbuf = NULL;
        }
        if (d->bd_hbuf != NULL) {
                FREE(d->bd_hbuf, M_DEVBUF);
                d->bd_hbuf = NULL;
        }
        if (d->bd_fbuf != NULL) {
                FREE(d->bd_fbuf, M_DEVBUF);
                d->bd_fbuf = NULL;
        }

        d->bd_fbuf = (caddr_t) _MALLOC(d->bd_bufsize, M_DEVBUF, M_WAIT);
        if (d->bd_fbuf == NULL) {
                return ENOBUFS;
        }

        d->bd_sbuf = (caddr_t) _MALLOC(d->bd_bufsize, M_DEVBUF, M_WAIT);
        if (d->bd_sbuf == NULL) {
                FREE(d->bd_fbuf, M_DEVBUF);
                d->bd_fbuf = NULL;
                return ENOBUFS;
        }
        d->bd_slen = 0;
        d->bd_hlen = 0;
        d->bd_scnt = 0;
        d->bd_hcnt = 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_hbuf_read != 0) {
                panic("bpf buffer freed during read");
        }

        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(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)
{
        bpf_attach(ifp, dlt, hdrlen, NULL, NULL);
}

errno_t
bpf_attach(
        ifnet_t                 ifp,
        u_int32_t               dlt,
        u_int32_t               hdrlen,
        bpf_send_func   send,
        bpf_tap_func    tap)
{
        struct bpf_if *bp;
        struct bpf_if *bp_new;
        struct bpf_if *bp_before_first = NULL;
        struct bpf_if *bp_first = NULL;
        struct bpf_if *bp_last = NULL;
        boolean_t found;

        bp_new = (struct bpf_if *) _MALLOC(sizeof(*bp_new), M_DEVBUF,
            M_WAIT | M_ZERO);
        if (bp_new == 0) {
                panic("bpfattach");
        }

        lck_mtx_lock(bpf_mlock);

        /*
         * Check if this interface/dlt is already attached. Remember the
         * first and last attachment for this interface, as well as the
         * element before the first attachment.
         */
        found = FALSE;
        for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
                if (bp->bif_ifp != ifp) {
                        if (bp_first != NULL) {
                                /* no more elements for this interface */
                                break;
                        }
                        bp_before_first = bp;
                } else {
                        if (bp->bif_dlt == dlt) {
                                found = TRUE;
                                break;
                        }
                        if (bp_first == NULL) {
                                bp_first = bp;
                        }
                        bp_last = bp;
                }
        }
        if (found) {
                lck_mtx_unlock(bpf_mlock);
                printf("bpfattach - %s with dlt %d is already attached\n",
                    if_name(ifp), dlt);
                FREE(bp_new, M_DEVBUF);
                return EEXIST;
        }

        bp_new->bif_ifp = ifp;
        bp_new->bif_dlt = dlt;
        bp_new->bif_send = send;
        bp_new->bif_tap = tap;

        if (bp_first == NULL) {
                /* No other entries for this ifp */
                bp_new->bif_next = bpf_iflist;
                bpf_iflist = bp_new;
        } else {
                if (ifnet_type(ifp) == IFT_ETHER && dlt == DLT_EN10MB) {
                        /* Make this the first entry for this interface */
                        if (bp_before_first != NULL) {
                                /*  point the previous to us */
                                bp_before_first->bif_next = bp_new;
                        } else {
                                /* we're the new head */
                                bpf_iflist = bp_new;
                        }
                        bp_new->bif_next = bp_first;
                } else {
                        /* Add this after the last entry for this interface */
                        bp_new->bif_next = bp_last->bif_next;
                        bp_last->bif_next = bp_new;
                }
        }

        /*
         * 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_new->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen;
        bp_new->bif_exthdrlen = BPF_WORDALIGN(hdrlen +
            sizeof(struct bpf_hdr_ext)) - hdrlen;

        /* Take a reference on the interface */
        ifnet_reference(ifp);

        lck_mtx_unlock(bpf_mlock);

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

        return 0;
}

/*
 * 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, *bp_next;
        struct bpf_d    *d;

        if (bpf_debug != 0) {
                printf("%s: %s\n", __func__, if_name(ifp));
        }

        lck_mtx_lock(bpf_mlock);

        /*
         * Build the list of devices attached to that interface
         * that we need to free while keeping the lock to maintain
         * the integrity of the interface list
         */
        bp_prev = NULL;
        for (bp = bpf_iflist; bp != NULL; bp = bp_next) {
                bp_next = bp->bif_next;

                if (ifp != bp->bif_ifp) {
                        bp_prev = bp;
                        continue;
                }
                /* Unlink from the interface list */
                if (bp_prev) {
                        bp_prev->bif_next = bp->bif_next;
                } else {
                        bpf_iflist = bp->bif_next;
                }

                /* Detach the devices attached to the interface */
                while ((d = bp->bif_dlist) != NULL) {
                        /*
                         * Take an extra reference to prevent the device
                         * from being freed when bpf_detachd() releases
                         * the reference for the interface list
                         */
                        bpf_acquire_d(d);
                        bpf_detachd(d, 0);
                        bpf_wakeup(d);
                        bpf_release_d(d);
                }
                ifnet_release(ifp);
        }

        lck_mtx_unlock(bpf_mlock);
}

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();
                bpf_mlock_grp = lck_grp_alloc_init("bpf", bpf_mlock_grp_attr);
                bpf_mlock_attr = lck_attr_alloc_init();
                lck_mtx_init(bpf_mlock, bpf_mlock_grp, bpf_mlock_attr);
                maj = cdevsw_add(CDEV_MAJOR, &bpf_cdevsw);
                if (maj == -1) {
                        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 = NULL;
                        bpf_mlock_attr = NULL;
                        bpf_mlock_grp = NULL;
                        bpf_mlock_grp_attr = NULL;
                        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

static int
sysctl_bpf_maxbufsize SYSCTL_HANDLER_ARGS
{
#pragma unused(arg1, arg2)
        int i, err;

        i = bpf_maxbufsize;

        err = sysctl_handle_int(oidp, &i, 0, req);
        if (err != 0 || req->newptr == USER_ADDR_NULL) {
                return err;
        }

        if (i < 0 || i > BPF_MAXSIZE_CAP) {
                i = BPF_MAXSIZE_CAP;
        }

        bpf_maxbufsize = i;
        return err;
}