net: Enter a net epoch around protocol if_up/down notifications

[FreeBSD/FreeBSD.git] / sys / net / if.c

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1980, 1986, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * 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. 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.
 *
 *      @(#)if.c        8.5 (Berkeley) 1/9/95
 * $FreeBSD$
 */

#include "opt_bpf.h"
#include "opt_inet6.h"
#include "opt_inet.h"

#include <sys/param.h>
#include <sys/conf.h>
#include <sys/eventhandler.h>
#include <sys/malloc.h>
#include <sys/domainset.h>
#include <sys/sbuf.h>
#include <sys/bus.h>
#include <sys/epoch.h>
#include <sys/mbuf.h>
#include <sys/systm.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/protosw.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/refcount.h>
#include <sys/module.h>
#include <sys/rwlock.h>
#include <sys/sockio.h>
#include <sys/syslog.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/taskqueue.h>
#include <sys/domain.h>
#include <sys/jail.h>
#include <sys/priv.h>

#include <machine/stdarg.h>
#include <vm/uma.h>

#include <net/bpf.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <net/if_clone.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/if_var.h>
#include <net/if_media.h>
#include <net/if_vlan_var.h>
#include <net/radix.h>
#include <net/route.h>
#include <net/route/route_ctl.h>
#include <net/vnet.h>

#if defined(INET) || defined(INET6)
#include <net/ethernet.h>
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_carp.h>
#ifdef INET
#include <net/debugnet.h>
#include <netinet/if_ether.h>
#endif /* INET */
#ifdef INET6
#include <netinet6/in6_var.h>
#include <netinet6/in6_ifattach.h>
#endif /* INET6 */
#endif /* INET || INET6 */

#include <security/mac/mac_framework.h>

/*
 * Consumers of struct ifreq such as tcpdump assume no pad between ifr_name
 * and ifr_ifru when it is used in SIOCGIFCONF.
 */
_Static_assert(sizeof(((struct ifreq *)0)->ifr_name) ==
    offsetof(struct ifreq, ifr_ifru), "gap between ifr_name and ifr_ifru");

__read_mostly epoch_t net_epoch_preempt;
#ifdef COMPAT_FREEBSD32
#include <sys/mount.h>
#include <compat/freebsd32/freebsd32.h>

struct ifreq_buffer32 {
        uint32_t        length;         /* (size_t) */
        uint32_t        buffer;         /* (void *) */
};

/*
 * Interface request structure used for socket
 * ioctl's.  All interface ioctl's must have parameter
 * definitions which begin with ifr_name.  The
 * remainder may be interface specific.
 */
struct ifreq32 {
        char    ifr_name[IFNAMSIZ];             /* if name, e.g. "en0" */
        union {
                struct sockaddr ifru_addr;
                struct sockaddr ifru_dstaddr;
                struct sockaddr ifru_broadaddr;
                struct ifreq_buffer32 ifru_buffer;
                short           ifru_flags[2];
                short           ifru_index;
                int             ifru_jid;
                int             ifru_metric;
                int             ifru_mtu;
                int             ifru_phys;
                int             ifru_media;
                uint32_t        ifru_data;
                int             ifru_cap[2];
                u_int           ifru_fib;
                u_char          ifru_vlan_pcp;
        } ifr_ifru;
};
CTASSERT(sizeof(struct ifreq) == sizeof(struct ifreq32));
CTASSERT(__offsetof(struct ifreq, ifr_ifru) ==
    __offsetof(struct ifreq32, ifr_ifru));

struct ifgroupreq32 {
        char    ifgr_name[IFNAMSIZ];
        u_int   ifgr_len;
        union {
                char            ifgru_group[IFNAMSIZ];
                uint32_t        ifgru_groups;
        } ifgr_ifgru;
};

struct ifmediareq32 {
        char            ifm_name[IFNAMSIZ];
        int             ifm_current;
        int             ifm_mask;
        int             ifm_status;
        int             ifm_active;
        int             ifm_count;
        uint32_t        ifm_ulist;      /* (int *) */
};
#define SIOCGIFMEDIA32  _IOC_NEWTYPE(SIOCGIFMEDIA, struct ifmediareq32)
#define SIOCGIFXMEDIA32 _IOC_NEWTYPE(SIOCGIFXMEDIA, struct ifmediareq32)

#define _CASE_IOC_IFGROUPREQ_32(cmd)                            \
    _IOC_NEWTYPE((cmd), struct ifgroupreq32): case
#else /* !COMPAT_FREEBSD32 */
#define _CASE_IOC_IFGROUPREQ_32(cmd)
#endif /* !COMPAT_FREEBSD32 */

#define CASE_IOC_IFGROUPREQ(cmd)        \
    _CASE_IOC_IFGROUPREQ_32(cmd)        \
    (cmd)

union ifreq_union {
        struct ifreq    ifr;
#ifdef COMPAT_FREEBSD32
        struct ifreq32  ifr32;
#endif
};

union ifgroupreq_union {
        struct ifgroupreq ifgr;
#ifdef COMPAT_FREEBSD32
        struct ifgroupreq32 ifgr32;
#endif
};

SYSCTL_NODE(_net, PF_LINK, link, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "Link layers");
SYSCTL_NODE(_net_link, 0, generic, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "Generic link-management");

SYSCTL_INT(_net_link, OID_AUTO, ifqmaxlen, CTLFLAG_RDTUN,
    &ifqmaxlen, 0, "max send queue size");

/* Log link state change events */
static int log_link_state_change = 1;

SYSCTL_INT(_net_link, OID_AUTO, log_link_state_change, CTLFLAG_RW,
        &log_link_state_change, 0,
        "log interface link state change events");

/* Log promiscuous mode change events */
static int log_promisc_mode_change = 1;

SYSCTL_INT(_net_link, OID_AUTO, log_promisc_mode_change, CTLFLAG_RDTUN,
        &log_promisc_mode_change, 1,
        "log promiscuous mode change events");

/* Interface description */
static unsigned int ifdescr_maxlen = 1024;
SYSCTL_UINT(_net, OID_AUTO, ifdescr_maxlen, CTLFLAG_RW,
        &ifdescr_maxlen, 0,
        "administrative maximum length for interface description");

static MALLOC_DEFINE(M_IFDESCR, "ifdescr", "ifnet descriptions");

/* global sx for non-critical path ifdescr */
static struct sx ifdescr_sx;
SX_SYSINIT(ifdescr_sx, &ifdescr_sx, "ifnet descr");

void    (*ng_ether_link_state_p)(struct ifnet *ifp, int state);
void    (*lagg_linkstate_p)(struct ifnet *ifp, int state);
/* These are external hooks for CARP. */
void    (*carp_linkstate_p)(struct ifnet *ifp);
void    (*carp_demote_adj_p)(int, char *);
int     (*carp_master_p)(struct ifaddr *);
#if defined(INET) || defined(INET6)
int     (*carp_forus_p)(struct ifnet *ifp, u_char *dhost);
int     (*carp_output_p)(struct ifnet *ifp, struct mbuf *m,
    const struct sockaddr *sa);
int     (*carp_ioctl_p)(struct ifreq *, u_long, struct thread *);   
int     (*carp_attach_p)(struct ifaddr *, int);
void    (*carp_detach_p)(struct ifaddr *, bool);
#endif
#ifdef INET
int     (*carp_iamatch_p)(struct ifaddr *, uint8_t **);
#endif
#ifdef INET6
struct ifaddr *(*carp_iamatch6_p)(struct ifnet *ifp, struct in6_addr *taddr6);
caddr_t (*carp_macmatch6_p)(struct ifnet *ifp, struct mbuf *m,
    const struct in6_addr *taddr);
#endif

struct mbuf *(*tbr_dequeue_ptr)(struct ifaltq *, int) = NULL;

/*
 * XXX: Style; these should be sorted alphabetically, and unprototyped
 * static functions should be prototyped. Currently they are sorted by
 * declaration order.
 */
static void     if_attachdomain(void *);
static void     if_attachdomain1(struct ifnet *);
static int      ifconf(u_long, caddr_t);
static void     *if_grow(void);
static void     if_input_default(struct ifnet *, struct mbuf *);
static int      if_requestencap_default(struct ifnet *, struct if_encap_req *);
static void     if_route(struct ifnet *, int flag, int fam);
static int      if_setflag(struct ifnet *, int, int, int *, int);
static int      if_transmit(struct ifnet *ifp, struct mbuf *m);
static void     if_unroute(struct ifnet *, int flag, int fam);
static int      if_delmulti_locked(struct ifnet *, struct ifmultiaddr *, int);
static void     do_link_state_change(void *, int);
static int      if_getgroup(struct ifgroupreq *, struct ifnet *);
static int      if_getgroupmembers(struct ifgroupreq *);
static void     if_delgroups(struct ifnet *);
static void     if_attach_internal(struct ifnet *, int, struct if_clone *);
static int      if_detach_internal(struct ifnet *, int, struct if_clone **);
static void     if_siocaddmulti(void *, int);
static void     if_link_ifnet(struct ifnet *);
static bool     if_unlink_ifnet(struct ifnet *, bool);
#ifdef VIMAGE
static int      if_vmove(struct ifnet *, struct vnet *);
#endif

#ifdef INET6
/*
 * XXX: declare here to avoid to include many inet6 related files..
 * should be more generalized?
 */
extern void     nd6_setmtu(struct ifnet *);
#endif

/* ipsec helper hooks */
VNET_DEFINE(struct hhook_head *, ipsec_hhh_in[HHOOK_IPSEC_COUNT]);
VNET_DEFINE(struct hhook_head *, ipsec_hhh_out[HHOOK_IPSEC_COUNT]);

VNET_DEFINE(int, if_index);
int     ifqmaxlen = IFQ_MAXLEN;
VNET_DEFINE(struct ifnethead, ifnet);   /* depend on static init XXX */
VNET_DEFINE(struct ifgrouphead, ifg_head);

VNET_DEFINE_STATIC(int, if_indexlim) = 8;

/* Table of ifnet by index. */
VNET_DEFINE(struct ifnet **, ifindex_table);

#define V_if_indexlim           VNET(if_indexlim)
#define V_ifindex_table         VNET(ifindex_table)

/*
 * The global network interface list (V_ifnet) and related state (such as
 * if_index, if_indexlim, and ifindex_table) are protected by an sxlock.
 * This may be acquired to stabilise the list, or we may rely on NET_EPOCH.
 */
struct sx ifnet_sxlock;
SX_SYSINIT_FLAGS(ifnet_sx, &ifnet_sxlock, "ifnet_sx", SX_RECURSE);

struct sx ifnet_detach_sxlock;
SX_SYSINIT_FLAGS(ifnet_detach, &ifnet_detach_sxlock, "ifnet_detach_sx",
    SX_RECURSE);

/*
 * The allocation of network interfaces is a rather non-atomic affair; we
 * need to select an index before we are ready to expose the interface for
 * use, so will use this pointer value to indicate reservation.
 */
#define IFNET_HOLD      (void *)(uintptr_t)(-1)

#ifdef VIMAGE
#define VNET_IS_SHUTTING_DOWN(_vnet)                                    \
    ((_vnet)->vnet_shutdown && (_vnet)->vnet_state < SI_SUB_VNET_DONE)
#endif

static  if_com_alloc_t *if_com_alloc[256];
static  if_com_free_t *if_com_free[256];

static MALLOC_DEFINE(M_IFNET, "ifnet", "interface internals");
MALLOC_DEFINE(M_IFADDR, "ifaddr", "interface address");
MALLOC_DEFINE(M_IFMADDR, "ether_multi", "link-level multicast address");

struct ifnet *
ifnet_byindex(u_short idx)
{
        struct ifnet *ifp;

        if (__predict_false(idx > V_if_index))
                return (NULL);

        ifp = *(struct ifnet * const volatile *)(V_ifindex_table + idx);
        return (__predict_false(ifp == IFNET_HOLD) ? NULL : ifp);
}

struct ifnet *
ifnet_byindex_ref(u_short idx)
{
        struct ifnet *ifp;

        NET_EPOCH_ASSERT();

        ifp = ifnet_byindex(idx);
        if (ifp == NULL || (ifp->if_flags & IFF_DYING))
                return (NULL);
        if (!if_try_ref(ifp))
                return (NULL);
        return (ifp);
}

/*
 * Allocate an ifindex array entry; return 0 on success or an error on
 * failure.
 */
static u_short
ifindex_alloc(void **old)
{
        u_short idx;

        IFNET_WLOCK_ASSERT();
        /*
         * Try to find an empty slot below V_if_index.  If we fail, take the
         * next slot.
         */
        for (idx = 1; idx <= V_if_index; idx++) {
                if (V_ifindex_table[idx] == NULL)
                        break;
        }

        /* Catch if_index overflow. */
        if (idx >= V_if_indexlim) {
                *old = if_grow();
                return (USHRT_MAX);
        }
        if (idx > V_if_index)
                V_if_index = idx;
        return (idx);
}

static void
ifindex_free_locked(u_short idx)
{

        IFNET_WLOCK_ASSERT();

        V_ifindex_table[idx] = NULL;
        while (V_if_index > 0 &&
            V_ifindex_table[V_if_index] == NULL)
                V_if_index--;
}

static void
ifindex_free(u_short idx)
{

        IFNET_WLOCK();
        ifindex_free_locked(idx);
        IFNET_WUNLOCK();
}

static void
ifnet_setbyindex(u_short idx, struct ifnet *ifp)
{

        V_ifindex_table[idx] = ifp;
}

struct ifaddr *
ifaddr_byindex(u_short idx)
{
        struct ifnet *ifp;
        struct ifaddr *ifa = NULL;

        NET_EPOCH_ASSERT();

        ifp = ifnet_byindex(idx);
        if (ifp != NULL && (ifa = ifp->if_addr) != NULL)
                ifa_ref(ifa);
        return (ifa);
}

/*
 * Network interface utility routines.
 *
 * Routines with ifa_ifwith* names take sockaddr *'s as
 * parameters.
 */

static void
vnet_if_init(const void *unused __unused)
{
        void *old;

        CK_STAILQ_INIT(&V_ifnet);
        CK_STAILQ_INIT(&V_ifg_head);
        IFNET_WLOCK();
        old = if_grow();                                /* create initial table */
        IFNET_WUNLOCK();
        epoch_wait_preempt(net_epoch_preempt);
        free(old, M_IFNET);
        vnet_if_clone_init();
}
VNET_SYSINIT(vnet_if_init, SI_SUB_INIT_IF, SI_ORDER_SECOND, vnet_if_init,
    NULL);

#ifdef VIMAGE
static void
vnet_if_uninit(const void *unused __unused)
{

        VNET_ASSERT(CK_STAILQ_EMPTY(&V_ifnet), ("%s:%d tailq &V_ifnet=%p "
            "not empty", __func__, __LINE__, &V_ifnet));
        VNET_ASSERT(CK_STAILQ_EMPTY(&V_ifg_head), ("%s:%d tailq &V_ifg_head=%p "
            "not empty", __func__, __LINE__, &V_ifg_head));

        free((caddr_t)V_ifindex_table, M_IFNET);
}
VNET_SYSUNINIT(vnet_if_uninit, SI_SUB_INIT_IF, SI_ORDER_FIRST,
    vnet_if_uninit, NULL);
#endif

static void
if_link_ifnet(struct ifnet *ifp)
{

        IFNET_WLOCK();
        CK_STAILQ_INSERT_TAIL(&V_ifnet, ifp, if_link);
#ifdef VIMAGE
        curvnet->vnet_ifcnt++;
#endif
        IFNET_WUNLOCK();
}

static bool
if_unlink_ifnet(struct ifnet *ifp, bool vmove)
{
        struct ifnet *iter;
        int found = 0;

        IFNET_WLOCK();
        CK_STAILQ_FOREACH(iter, &V_ifnet, if_link)
                if (iter == ifp) {
                        CK_STAILQ_REMOVE(&V_ifnet, ifp, ifnet, if_link);
                        if (!vmove)
                                ifp->if_flags |= IFF_DYING;
                        found = 1;
                        break;
                }
#ifdef VIMAGE
        curvnet->vnet_ifcnt--;
#endif
        IFNET_WUNLOCK();

        return (found);
}

#ifdef VIMAGE
static void
vnet_if_return(const void *unused __unused)
{
        struct ifnet *ifp, *nifp;
        struct ifnet **pending;
        int found, i;

        i = 0;

        /*
         * We need to protect our access to the V_ifnet tailq. Ordinarily we'd
         * enter NET_EPOCH, but that's not possible, because if_vmove() calls
         * if_detach_internal(), which waits for NET_EPOCH callbacks to
         * complete. We can't do that from within NET_EPOCH.
         *
         * However, we can also use the IFNET_xLOCK, which is the V_ifnet
         * read/write lock. We cannot hold the lock as we call if_vmove()
         * though, as that presents LOR w.r.t ifnet_sx, in_multi_sx and iflib
         * ctx lock.
         */
        IFNET_WLOCK();

        pending = malloc(sizeof(struct ifnet *) * curvnet->vnet_ifcnt,
            M_IFNET, M_WAITOK | M_ZERO);

        /* Return all inherited interfaces to their parent vnets. */
        CK_STAILQ_FOREACH_SAFE(ifp, &V_ifnet, if_link, nifp) {
                if (ifp->if_home_vnet != ifp->if_vnet) {
                        found = if_unlink_ifnet(ifp, true);
                        MPASS(found);

                        pending[i++] = ifp;
                }
        }
        IFNET_WUNLOCK();

        for (int j = 0; j < i; j++) {
                if_vmove(pending[j], pending[j]->if_home_vnet);
        }

        free(pending, M_IFNET);
}
VNET_SYSUNINIT(vnet_if_return, SI_SUB_VNET_DONE, SI_ORDER_ANY,
    vnet_if_return, NULL);
#endif

static void *
if_grow(void)
{
        int oldlim;
        u_int n;
        struct ifnet **e;
        void *old;

        old = NULL;
        IFNET_WLOCK_ASSERT();
        oldlim = V_if_indexlim;
        IFNET_WUNLOCK();
        n = (oldlim << 1) * sizeof(*e);
        e = malloc(n, M_IFNET, M_WAITOK | M_ZERO);
        IFNET_WLOCK();
        if (V_if_indexlim != oldlim) {
                free(e, M_IFNET);
                return (NULL);
        }
        if (V_ifindex_table != NULL) {
                memcpy((caddr_t)e, (caddr_t)V_ifindex_table, n/2);
                old = V_ifindex_table;
        }
        V_if_indexlim <<= 1;
        V_ifindex_table = e;
        return (old);
}

/*
 * Allocate a struct ifnet and an index for an interface.  A layer 2
 * common structure will also be allocated if an allocation routine is
 * registered for the passed type.
 */
struct ifnet *
if_alloc_domain(u_char type, int numa_domain)
{
        struct ifnet *ifp;
        u_short idx;
        void *old;

        KASSERT(numa_domain <= IF_NODOM, ("numa_domain too large"));
        if (numa_domain == IF_NODOM)
                ifp = malloc(sizeof(struct ifnet), M_IFNET,
                    M_WAITOK | M_ZERO);
        else
                ifp = malloc_domainset(sizeof(struct ifnet), M_IFNET,
                    DOMAINSET_PREF(numa_domain), M_WAITOK | M_ZERO);
 restart:
        IFNET_WLOCK();
        idx = ifindex_alloc(&old);
        if (__predict_false(idx == USHRT_MAX)) {
                IFNET_WUNLOCK();
                epoch_wait_preempt(net_epoch_preempt);
                free(old, M_IFNET);
                goto restart;
        }
        ifnet_setbyindex(idx, IFNET_HOLD);
        IFNET_WUNLOCK();
        ifp->if_index = idx;
        ifp->if_type = type;
        ifp->if_alloctype = type;
        ifp->if_numa_domain = numa_domain;
#ifdef VIMAGE
        ifp->if_vnet = curvnet;
#endif
        if (if_com_alloc[type] != NULL) {
                ifp->if_l2com = if_com_alloc[type](type, ifp);
                if (ifp->if_l2com == NULL) {
                        free(ifp, M_IFNET);
                        ifindex_free(idx);
                        return (NULL);
                }
        }

        IF_ADDR_LOCK_INIT(ifp);
        TASK_INIT(&ifp->if_linktask, 0, do_link_state_change, ifp);
        TASK_INIT(&ifp->if_addmultitask, 0, if_siocaddmulti, ifp);
        ifp->if_afdata_initialized = 0;
        IF_AFDATA_LOCK_INIT(ifp);
        CK_STAILQ_INIT(&ifp->if_addrhead);
        CK_STAILQ_INIT(&ifp->if_multiaddrs);
        CK_STAILQ_INIT(&ifp->if_groups);
#ifdef MAC
        mac_ifnet_init(ifp);
#endif
        ifq_init(&ifp->if_snd, ifp);

        refcount_init(&ifp->if_refcount, 1);    /* Index reference. */
        for (int i = 0; i < IFCOUNTERS; i++)
                ifp->if_counters[i] = counter_u64_alloc(M_WAITOK);
        ifp->if_get_counter = if_get_counter_default;
        ifp->if_pcp = IFNET_PCP_NONE;
        ifnet_setbyindex(ifp->if_index, ifp);
        return (ifp);
}

struct ifnet *
if_alloc_dev(u_char type, device_t dev)
{
        int numa_domain;

        if (dev == NULL || bus_get_domain(dev, &numa_domain) != 0)
                return (if_alloc_domain(type, IF_NODOM));
        return (if_alloc_domain(type, numa_domain));
}

struct ifnet *
if_alloc(u_char type)
{

        return (if_alloc_domain(type, IF_NODOM));
}
/*
 * Do the actual work of freeing a struct ifnet, and layer 2 common
 * structure.  This call is made when the last reference to an
 * interface is released.
 */
static void
if_free_internal(struct ifnet *ifp)
{

        KASSERT((ifp->if_flags & IFF_DYING),
            ("if_free_internal: interface not dying"));

        if (if_com_free[ifp->if_alloctype] != NULL)
                if_com_free[ifp->if_alloctype](ifp->if_l2com,
                    ifp->if_alloctype);

#ifdef MAC
        mac_ifnet_destroy(ifp);
#endif /* MAC */
        IF_AFDATA_DESTROY(ifp);
        IF_ADDR_LOCK_DESTROY(ifp);
        ifq_delete(&ifp->if_snd);

        for (int i = 0; i < IFCOUNTERS; i++)
                counter_u64_free(ifp->if_counters[i]);

        free(ifp->if_description, M_IFDESCR);
        free(ifp->if_hw_addr, M_IFADDR);
        free(ifp, M_IFNET);
}

static void
if_destroy(epoch_context_t ctx)
{
        struct ifnet *ifp;

        ifp = __containerof(ctx, struct ifnet, if_epoch_ctx);
        if_free_internal(ifp);
}

/*
 * Deregister an interface and free the associated storage.
 */
void
if_free(struct ifnet *ifp)
{

        ifp->if_flags |= IFF_DYING;                     /* XXX: Locking */

        CURVNET_SET_QUIET(ifp->if_vnet);
        IFNET_WLOCK();
        KASSERT(ifp == ifnet_byindex(ifp->if_index),
            ("%s: freeing unallocated ifnet", ifp->if_xname));

        ifindex_free_locked(ifp->if_index);
        IFNET_WUNLOCK();

        if (refcount_release(&ifp->if_refcount))
                NET_EPOCH_CALL(if_destroy, &ifp->if_epoch_ctx);
        CURVNET_RESTORE();
}

/*
 * Interfaces to keep an ifnet type-stable despite the possibility of the
 * driver calling if_free().  If there are additional references, we defer
 * freeing the underlying data structure.
 */
void
if_ref(struct ifnet *ifp)
{
        u_int old;

        /* We don't assert the ifnet list lock here, but arguably should. */
        old = refcount_acquire(&ifp->if_refcount);
        KASSERT(old > 0, ("%s: ifp %p has 0 refs", __func__, ifp));
}

bool
if_try_ref(struct ifnet *ifp)
{
        NET_EPOCH_ASSERT();
        return (refcount_acquire_if_not_zero(&ifp->if_refcount));
}

void
if_rele(struct ifnet *ifp)
{

        if (!refcount_release(&ifp->if_refcount))
                return;
        NET_EPOCH_CALL(if_destroy, &ifp->if_epoch_ctx);
}

void
ifq_init(struct ifaltq *ifq, struct ifnet *ifp)
{

        mtx_init(&ifq->ifq_mtx, ifp->if_xname, "if send queue", MTX_DEF);

        if (ifq->ifq_maxlen == 0) 
                ifq->ifq_maxlen = ifqmaxlen;

        ifq->altq_type = 0;
        ifq->altq_disc = NULL;
        ifq->altq_flags &= ALTQF_CANTCHANGE;
        ifq->altq_tbr  = NULL;
        ifq->altq_ifp  = ifp;
}

void
ifq_delete(struct ifaltq *ifq)
{
        mtx_destroy(&ifq->ifq_mtx);
}

/*
 * Perform generic interface initialization tasks and attach the interface
 * to the list of "active" interfaces.  If vmove flag is set on entry
 * to if_attach_internal(), perform only a limited subset of initialization
 * tasks, given that we are moving from one vnet to another an ifnet which
 * has already been fully initialized.
 *
 * Note that if_detach_internal() removes group membership unconditionally
 * even when vmove flag is set, and if_attach_internal() adds only IFG_ALL.
 * Thus, when if_vmove() is applied to a cloned interface, group membership
 * is lost while a cloned one always joins a group whose name is
 * ifc->ifc_name.  To recover this after if_detach_internal() and
 * if_attach_internal(), the cloner should be specified to
 * if_attach_internal() via ifc.  If it is non-NULL, if_attach_internal()
 * attempts to join a group whose name is ifc->ifc_name.
 *
 * XXX:
 *  - The decision to return void and thus require this function to
 *    succeed is questionable.
 *  - We should probably do more sanity checking.  For instance we don't
 *    do anything to insure if_xname is unique or non-empty.
 */
void
if_attach(struct ifnet *ifp)
{

        if_attach_internal(ifp, 0, NULL);
}

/*
 * Compute the least common TSO limit.
 */
void
if_hw_tsomax_common(if_t ifp, struct ifnet_hw_tsomax *pmax)
{
        /*
         * 1) If there is no limit currently, take the limit from
         * the network adapter.
         *
         * 2) If the network adapter has a limit below the current
         * limit, apply it.
         */
        if (pmax->tsomaxbytes == 0 || (ifp->if_hw_tsomax != 0 &&
            ifp->if_hw_tsomax < pmax->tsomaxbytes)) {
                pmax->tsomaxbytes = ifp->if_hw_tsomax;
        }
        if (pmax->tsomaxsegcount == 0 || (ifp->if_hw_tsomaxsegcount != 0 &&
            ifp->if_hw_tsomaxsegcount < pmax->tsomaxsegcount)) {
                pmax->tsomaxsegcount = ifp->if_hw_tsomaxsegcount;
        }
        if (pmax->tsomaxsegsize == 0 || (ifp->if_hw_tsomaxsegsize != 0 &&
            ifp->if_hw_tsomaxsegsize < pmax->tsomaxsegsize)) {
                pmax->tsomaxsegsize = ifp->if_hw_tsomaxsegsize;
        }
}

/*
 * Update TSO limit of a network adapter.
 *
 * Returns zero if no change. Else non-zero.
 */
int
if_hw_tsomax_update(if_t ifp, struct ifnet_hw_tsomax *pmax)
{
        int retval = 0;
        if (ifp->if_hw_tsomax != pmax->tsomaxbytes) {
                ifp->if_hw_tsomax = pmax->tsomaxbytes;
                retval++;
        }
        if (ifp->if_hw_tsomaxsegsize != pmax->tsomaxsegsize) {
                ifp->if_hw_tsomaxsegsize = pmax->tsomaxsegsize;
                retval++;
        }
        if (ifp->if_hw_tsomaxsegcount != pmax->tsomaxsegcount) {
                ifp->if_hw_tsomaxsegcount = pmax->tsomaxsegcount;
                retval++;
        }
        return (retval);
}

static void
if_attach_internal(struct ifnet *ifp, int vmove, struct if_clone *ifc)
{
        unsigned socksize, ifasize;
        int namelen, masklen;
        struct sockaddr_dl *sdl;
        struct ifaddr *ifa;

        if (ifp->if_index == 0 || ifp != ifnet_byindex(ifp->if_index))
                panic ("%s: BUG: if_attach called without if_alloc'd input()\n",
                    ifp->if_xname);

#ifdef VIMAGE
        ifp->if_vnet = curvnet;
        if (ifp->if_home_vnet == NULL)
                ifp->if_home_vnet = curvnet;
#endif

        if_addgroup(ifp, IFG_ALL);

        /* Restore group membership for cloned interfaces. */
        if (vmove && ifc != NULL)
                if_clone_addgroup(ifp, ifc);

        getmicrotime(&ifp->if_lastchange);
        ifp->if_epoch = time_uptime;

        KASSERT((ifp->if_transmit == NULL && ifp->if_qflush == NULL) ||
            (ifp->if_transmit != NULL && ifp->if_qflush != NULL),
            ("transmit and qflush must both either be set or both be NULL"));
        if (ifp->if_transmit == NULL) {
                ifp->if_transmit = if_transmit;
                ifp->if_qflush = if_qflush;
        }
        if (ifp->if_input == NULL)
                ifp->if_input = if_input_default;

        if (ifp->if_requestencap == NULL)
                ifp->if_requestencap = if_requestencap_default;

        if (!vmove) {
#ifdef MAC
                mac_ifnet_create(ifp);
#endif

                /*
                 * Create a Link Level name for this device.
                 */
                namelen = strlen(ifp->if_xname);
                /*
                 * Always save enough space for any possiable name so we
                 * can do a rename in place later.
                 */
                masklen = offsetof(struct sockaddr_dl, sdl_data[0]) + IFNAMSIZ;
                socksize = masklen + ifp->if_addrlen;
                if (socksize < sizeof(*sdl))
                        socksize = sizeof(*sdl);
                socksize = roundup2(socksize, sizeof(long));
                ifasize = sizeof(*ifa) + 2 * socksize;
                ifa = ifa_alloc(ifasize, M_WAITOK);
                sdl = (struct sockaddr_dl *)(ifa + 1);
                sdl->sdl_len = socksize;
                sdl->sdl_family = AF_LINK;
                bcopy(ifp->if_xname, sdl->sdl_data, namelen);
                sdl->sdl_nlen = namelen;
                sdl->sdl_index = ifp->if_index;
                sdl->sdl_type = ifp->if_type;
                ifp->if_addr = ifa;
                ifa->ifa_ifp = ifp;
                ifa->ifa_addr = (struct sockaddr *)sdl;
                sdl = (struct sockaddr_dl *)(socksize + (caddr_t)sdl);
                ifa->ifa_netmask = (struct sockaddr *)sdl;
                sdl->sdl_len = masklen;
                while (namelen != 0)
                        sdl->sdl_data[--namelen] = 0xff;
                CK_STAILQ_INSERT_HEAD(&ifp->if_addrhead, ifa, ifa_link);
                /* Reliably crash if used uninitialized. */
                ifp->if_broadcastaddr = NULL;

                if (ifp->if_type == IFT_ETHER) {
                        ifp->if_hw_addr = malloc(ifp->if_addrlen, M_IFADDR,
                            M_WAITOK | M_ZERO);
                }

#if defined(INET) || defined(INET6)
                /* Use defaults for TSO, if nothing is set */
                if (ifp->if_hw_tsomax == 0 &&
                    ifp->if_hw_tsomaxsegcount == 0 &&
                    ifp->if_hw_tsomaxsegsize == 0) {
                        /*
                         * The TSO defaults needs to be such that an
                         * NFS mbuf list of 35 mbufs totalling just
                         * below 64K works and that a chain of mbufs
                         * can be defragged into at most 32 segments:
                         */
                        ifp->if_hw_tsomax = min(IP_MAXPACKET, (32 * MCLBYTES) -
                            (ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN));
                        ifp->if_hw_tsomaxsegcount = 35;
                        ifp->if_hw_tsomaxsegsize = 2048;        /* 2K */

                        /* XXX some drivers set IFCAP_TSO after ethernet attach */
                        if (ifp->if_capabilities & IFCAP_TSO) {
                                if_printf(ifp, "Using defaults for TSO: %u/%u/%u\n",
                                    ifp->if_hw_tsomax,
                                    ifp->if_hw_tsomaxsegcount,
                                    ifp->if_hw_tsomaxsegsize);
                        }
                }
#endif
        }
#ifdef VIMAGE
        else {
                /*
                 * Update the interface index in the link layer address
                 * of the interface.
                 */
                for (ifa = ifp->if_addr; ifa != NULL;
                    ifa = CK_STAILQ_NEXT(ifa, ifa_link)) {
                        if (ifa->ifa_addr->sa_family == AF_LINK) {
                                sdl = (struct sockaddr_dl *)ifa->ifa_addr;
                                sdl->sdl_index = ifp->if_index;
                        }
                }
        }
#endif

        if_link_ifnet(ifp);

        if (domain_init_status >= 2)
                if_attachdomain1(ifp);

        EVENTHANDLER_INVOKE(ifnet_arrival_event, ifp);
        if (IS_DEFAULT_VNET(curvnet))
                devctl_notify("IFNET", ifp->if_xname, "ATTACH", NULL);

        /* Announce the interface. */
        rt_ifannouncemsg(ifp, IFAN_ARRIVAL);
}

static void
if_epochalloc(void *dummy __unused)
{

        net_epoch_preempt = epoch_alloc("Net preemptible", EPOCH_PREEMPT);
}
SYSINIT(ifepochalloc, SI_SUB_EPOCH, SI_ORDER_ANY, if_epochalloc, NULL);

static void
if_attachdomain(void *dummy)
{
        struct ifnet *ifp;

        CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link)
                if_attachdomain1(ifp);
}
SYSINIT(domainifattach, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_SECOND,
    if_attachdomain, NULL);

static void
if_attachdomain1(struct ifnet *ifp)
{
        struct domain *dp;

        /*
         * Since dp->dom_ifattach calls malloc() with M_WAITOK, we
         * cannot lock ifp->if_afdata initialization, entirely.
         */
        IF_AFDATA_LOCK(ifp);
        if (ifp->if_afdata_initialized >= domain_init_status) {
                IF_AFDATA_UNLOCK(ifp);
                log(LOG_WARNING, "%s called more than once on %s\n",
                    __func__, ifp->if_xname);
                return;
        }
        ifp->if_afdata_initialized = domain_init_status;
        IF_AFDATA_UNLOCK(ifp);

        /* address family dependent data region */
        bzero(ifp->if_afdata, sizeof(ifp->if_afdata));
        for (dp = domains; dp; dp = dp->dom_next) {
                if (dp->dom_ifattach)
                        ifp->if_afdata[dp->dom_family] =
                            (*dp->dom_ifattach)(ifp);
        }
}

/*
 * Remove any unicast or broadcast network addresses from an interface.
 */
void
if_purgeaddrs(struct ifnet *ifp)
{
        struct ifaddr *ifa;

        while (1) {
                struct epoch_tracker et;

                NET_EPOCH_ENTER(et);
                CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                        if (ifa->ifa_addr->sa_family != AF_LINK)
                                break;
                }
                NET_EPOCH_EXIT(et);

                if (ifa == NULL)
                        break;
#ifdef INET
                /* XXX: Ugly!! ad hoc just for INET */
                if (ifa->ifa_addr->sa_family == AF_INET) {
                        struct ifaliasreq ifr;

                        bzero(&ifr, sizeof(ifr));
                        ifr.ifra_addr = *ifa->ifa_addr;
                        if (ifa->ifa_dstaddr)
                                ifr.ifra_broadaddr = *ifa->ifa_dstaddr;
                        if (in_control(NULL, SIOCDIFADDR, (caddr_t)&ifr, ifp,
                            NULL) == 0)
                                continue;
                }
#endif /* INET */
#ifdef INET6
                if (ifa->ifa_addr->sa_family == AF_INET6) {
                        in6_purgeifaddr((struct in6_ifaddr *)ifa);
                        /* ifp_addrhead is already updated */
                        continue;
                }
#endif /* INET6 */
                IF_ADDR_WLOCK(ifp);
                CK_STAILQ_REMOVE(&ifp->if_addrhead, ifa, ifaddr, ifa_link);
                IF_ADDR_WUNLOCK(ifp);
                ifa_free(ifa);
        }
}

/*
 * Remove any multicast network addresses from an interface when an ifnet
 * is going away.
 */
static void
if_purgemaddrs(struct ifnet *ifp)
{
        struct ifmultiaddr *ifma;

        IF_ADDR_WLOCK(ifp);
        while (!CK_STAILQ_EMPTY(&ifp->if_multiaddrs)) {
                ifma = CK_STAILQ_FIRST(&ifp->if_multiaddrs);
                CK_STAILQ_REMOVE(&ifp->if_multiaddrs, ifma, ifmultiaddr, ifma_link);
                if_delmulti_locked(ifp, ifma, 1);
        }
        IF_ADDR_WUNLOCK(ifp);
}

/*
 * Detach an interface, removing it from the list of "active" interfaces.
 * If vmove flag is set on entry to if_detach_internal(), perform only a
 * limited subset of cleanup tasks, given that we are moving an ifnet from
 * one vnet to another, where it must be fully operational.
 *
 * XXXRW: There are some significant questions about event ordering, and
 * how to prevent things from starting to use the interface during detach.
 */
void
if_detach(struct ifnet *ifp)
{
        bool found;

        CURVNET_SET_QUIET(ifp->if_vnet);
        found = if_unlink_ifnet(ifp, false);
        if (found) {
                sx_xlock(&ifnet_detach_sxlock);
                if_detach_internal(ifp, 0, NULL);
                sx_xunlock(&ifnet_detach_sxlock);
        }
        CURVNET_RESTORE();
}

/*
 * The vmove flag, if set, indicates that we are called from a callpath
 * that is moving an interface to a different vnet instance.
 *
 * The shutdown flag, if set, indicates that we are called in the
 * process of shutting down a vnet instance.  Currently only the
 * vnet_if_return SYSUNINIT function sets it.  Note: we can be called
 * on a vnet instance shutdown without this flag being set, e.g., when
 * the cloned interfaces are destoyed as first thing of teardown.
 */
static int
if_detach_internal(struct ifnet *ifp, int vmove, struct if_clone **ifcp)
{
        struct ifaddr *ifa;
        int i;
        struct domain *dp;
#ifdef VIMAGE
        bool shutdown;

        shutdown = VNET_IS_SHUTTING_DOWN(ifp->if_vnet);
#endif

        /*
         * At this point we know the interface still was on the ifnet list
         * and we removed it so we are in a stable state.
         */
        epoch_wait_preempt(net_epoch_preempt);

        /*
         * Ensure all pending EPOCH(9) callbacks have been executed. This
         * fixes issues about late destruction of multicast options
         * which lead to leave group calls, which in turn access the
         * belonging ifnet structure:
         */
        epoch_drain_callbacks(net_epoch_preempt);

        /*
         * In any case (destroy or vmove) detach us from the groups
         * and remove/wait for pending events on the taskq.
         * XXX-BZ in theory an interface could still enqueue a taskq change?
         */
        if_delgroups(ifp);

        taskqueue_drain(taskqueue_swi, &ifp->if_linktask);
        taskqueue_drain(taskqueue_swi, &ifp->if_addmultitask);

        /*
         * Check if this is a cloned interface or not. Must do even if
         * shutting down as a if_vmove_reclaim() would move the ifp and
         * the if_clone_addgroup() will have a corrupted string overwise
         * from a gibberish pointer.
         */
        if (vmove && ifcp != NULL)
                *ifcp = if_clone_findifc(ifp);

        if_down(ifp);

#ifdef VIMAGE
        /*
         * On VNET shutdown abort here as the stack teardown will do all
         * the work top-down for us.
         */
        if (shutdown) {
                /* Give interface users the chance to clean up. */
                EVENTHANDLER_INVOKE(ifnet_departure_event, ifp);

                /*
                 * In case of a vmove we are done here without error.
                 * If we would signal an error it would lead to the same
                 * abort as if we did not find the ifnet anymore.
                 * if_detach() calls us in void context and does not care
                 * about an early abort notification, so life is splendid :)
                 */
                goto finish_vnet_shutdown;
        }
#endif

        /*
         * At this point we are not tearing down a VNET and are either
         * going to destroy or vmove the interface and have to cleanup
         * accordingly.
         */

        /*
         * Remove routes and flush queues.
         */
#ifdef ALTQ
        if (ALTQ_IS_ENABLED(&ifp->if_snd))
                altq_disable(&ifp->if_snd);
        if (ALTQ_IS_ATTACHED(&ifp->if_snd))
                altq_detach(&ifp->if_snd);
#endif

        if_purgeaddrs(ifp);

#ifdef INET
        in_ifdetach(ifp);
#endif

#ifdef INET6
        /*
         * Remove all IPv6 kernel structs related to ifp.  This should be done
         * before removing routing entries below, since IPv6 interface direct
         * routes are expected to be removed by the IPv6-specific kernel API.
         * Otherwise, the kernel will detect some inconsistency and bark it.
         */
        in6_ifdetach(ifp);
#endif
        if_purgemaddrs(ifp);

        /* Announce that the interface is gone. */
        rt_ifannouncemsg(ifp, IFAN_DEPARTURE);
        EVENTHANDLER_INVOKE(ifnet_departure_event, ifp);
        if (IS_DEFAULT_VNET(curvnet))
                devctl_notify("IFNET", ifp->if_xname, "DETACH", NULL);

        if (!vmove) {
                /*
                 * Prevent further calls into the device driver via ifnet.
                 */
                if_dead(ifp);

                /*
                 * Clean up all addresses.
                 */
                IF_ADDR_WLOCK(ifp);
                if (!CK_STAILQ_EMPTY(&ifp->if_addrhead)) {
                        ifa = CK_STAILQ_FIRST(&ifp->if_addrhead);
                        CK_STAILQ_REMOVE(&ifp->if_addrhead, ifa, ifaddr, ifa_link);
                        IF_ADDR_WUNLOCK(ifp);
                        ifa_free(ifa);
                } else
                        IF_ADDR_WUNLOCK(ifp);
        }

        rt_flushifroutes(ifp);

#ifdef VIMAGE
finish_vnet_shutdown:
#endif
        /*
         * We cannot hold the lock over dom_ifdetach calls as they might
         * sleep, for example trying to drain a callout, thus open up the
         * theoretical race with re-attaching.
         */
        IF_AFDATA_LOCK(ifp);
        i = ifp->if_afdata_initialized;
        ifp->if_afdata_initialized = 0;
        IF_AFDATA_UNLOCK(ifp);
        for (dp = domains; i > 0 && dp; dp = dp->dom_next) {
                if (dp->dom_ifdetach && ifp->if_afdata[dp->dom_family]) {
                        (*dp->dom_ifdetach)(ifp,
                            ifp->if_afdata[dp->dom_family]);
                        ifp->if_afdata[dp->dom_family] = NULL;
                }
        }

        return (0);
}

#ifdef VIMAGE
/*
 * if_vmove() performs a limited version of if_detach() in current
 * vnet and if_attach()es the ifnet to the vnet specified as 2nd arg.
 * An attempt is made to shrink if_index in current vnet, find an
 * unused if_index in target vnet and calls if_grow() if necessary,
 * and finally find an unused if_xname for the target vnet.
 */
static int
if_vmove(struct ifnet *ifp, struct vnet *new_vnet)
{
        struct if_clone *ifc;
#ifdef DEV_BPF
        u_int bif_dlt, bif_hdrlen;
#endif
        void *old;
        int rc;

#ifdef DEV_BPF
        /*
         * if_detach_internal() will call the eventhandler to notify
         * interface departure.  That will detach if_bpf.  We need to
         * safe the dlt and hdrlen so we can re-attach it later.
         */
        bpf_get_bp_params(ifp->if_bpf, &bif_dlt, &bif_hdrlen);
#endif

        /*
         * Detach from current vnet, but preserve LLADDR info, do not
         * mark as dead etc. so that the ifnet can be reattached later.
         * If we cannot find it, we lost the race to someone else.
         */
        rc = if_detach_internal(ifp, 1, &ifc);
        if (rc != 0)
                return (rc);

        /*
         * Unlink the ifnet from ifindex_table[] in current vnet, and shrink
         * the if_index for that vnet if possible.
         *
         * NOTE: IFNET_WLOCK/IFNET_WUNLOCK() are assumed to be unvirtualized,
         * or we'd lock on one vnet and unlock on another.
         */
        IFNET_WLOCK();
        ifindex_free_locked(ifp->if_index);
        IFNET_WUNLOCK();

        /*
         * Perform interface-specific reassignment tasks, if provided by
         * the driver.
         */
        if (ifp->if_reassign != NULL)
                ifp->if_reassign(ifp, new_vnet, NULL);

        /*
         * Switch to the context of the target vnet.
         */
        CURVNET_SET_QUIET(new_vnet);
 restart:
        IFNET_WLOCK();
        ifp->if_index = ifindex_alloc(&old);
        if (__predict_false(ifp->if_index == USHRT_MAX)) {
                IFNET_WUNLOCK();
                epoch_wait_preempt(net_epoch_preempt);
                free(old, M_IFNET);
                goto restart;
        }
        ifnet_setbyindex(ifp->if_index, ifp);
        IFNET_WUNLOCK();

        if_attach_internal(ifp, 1, ifc);

#ifdef DEV_BPF
        if (ifp->if_bpf == NULL)
                bpfattach(ifp, bif_dlt, bif_hdrlen);
#endif

        CURVNET_RESTORE();
        return (0);
}

/*
 * Move an ifnet to or from another child prison/vnet, specified by the jail id.
 */
static int
if_vmove_loan(struct thread *td, struct ifnet *ifp, char *ifname, int jid)
{
        struct prison *pr;
        struct ifnet *difp;
        int error;
        bool found;
        bool shutdown;

        /* Try to find the prison within our visibility. */
        sx_slock(&allprison_lock);
        pr = prison_find_child(td->td_ucred->cr_prison, jid);
        sx_sunlock(&allprison_lock);
        if (pr == NULL)
                return (ENXIO);
        prison_hold_locked(pr);
        mtx_unlock(&pr->pr_mtx);

        /* Do not try to move the iface from and to the same prison. */
        if (pr->pr_vnet == ifp->if_vnet) {
                prison_free(pr);
                return (EEXIST);
        }

        /* Make sure the named iface does not exists in the dst. prison/vnet. */
        /* XXX Lock interfaces to avoid races. */
        CURVNET_SET_QUIET(pr->pr_vnet);
        difp = ifunit(ifname);
        if (difp != NULL) {
                CURVNET_RESTORE();
                prison_free(pr);
                return (EEXIST);
        }

        /* Make sure the VNET is stable. */
        shutdown = VNET_IS_SHUTTING_DOWN(ifp->if_vnet);
        if (shutdown) {
                CURVNET_RESTORE();
                prison_free(pr);
                return (EBUSY);
        }
        CURVNET_RESTORE();

        found = if_unlink_ifnet(ifp, true);
        MPASS(found);

        /* Move the interface into the child jail/vnet. */
        error = if_vmove(ifp, pr->pr_vnet);

        /* Report the new if_xname back to the userland on success. */
        if (error == 0)
                sprintf(ifname, "%s", ifp->if_xname);

        prison_free(pr);
        return (error);
}

static int
if_vmove_reclaim(struct thread *td, char *ifname, int jid)
{
        struct prison *pr;
        struct vnet *vnet_dst;
        struct ifnet *ifp;
        int error, found;
        bool shutdown;

        /* Try to find the prison within our visibility. */
        sx_slock(&allprison_lock);
        pr = prison_find_child(td->td_ucred->cr_prison, jid);
        sx_sunlock(&allprison_lock);
        if (pr == NULL)
                return (ENXIO);
        prison_hold_locked(pr);
        mtx_unlock(&pr->pr_mtx);

        /* Make sure the named iface exists in the source prison/vnet. */
        CURVNET_SET(pr->pr_vnet);
        ifp = ifunit(ifname);           /* XXX Lock to avoid races. */
        if (ifp == NULL) {
                CURVNET_RESTORE();
                prison_free(pr);
                return (ENXIO);
        }

        /* Do not try to move the iface from and to the same prison. */
        vnet_dst = TD_TO_VNET(td);
        if (vnet_dst == ifp->if_vnet) {
                CURVNET_RESTORE();
                prison_free(pr);
                return (EEXIST);
        }

        /* Make sure the VNET is stable. */
        shutdown = VNET_IS_SHUTTING_DOWN(ifp->if_vnet);
        if (shutdown) {
                CURVNET_RESTORE();
                prison_free(pr);
                return (EBUSY);
        }

        /* Get interface back from child jail/vnet. */
        found = if_unlink_ifnet(ifp, true);
        MPASS(found);
        error = if_vmove(ifp, vnet_dst);
        CURVNET_RESTORE();

        /* Report the new if_xname back to the userland on success. */
        if (error == 0)
                sprintf(ifname, "%s", ifp->if_xname);

        prison_free(pr);
        return (error);
}
#endif /* VIMAGE */

/*
 * Add a group to an interface
 */
int
if_addgroup(struct ifnet *ifp, const char *groupname)
{
        struct ifg_list         *ifgl;
        struct ifg_group        *ifg = NULL;
        struct ifg_member       *ifgm;
        int                      new = 0;

        if (groupname[0] && groupname[strlen(groupname) - 1] >= '0' &&
            groupname[strlen(groupname) - 1] <= '9')
                return (EINVAL);

        IFNET_WLOCK();
        CK_STAILQ_FOREACH(ifgl, &ifp->if_groups, ifgl_next)
                if (!strcmp(ifgl->ifgl_group->ifg_group, groupname)) {
                        IFNET_WUNLOCK();
                        return (EEXIST);
                }

        if ((ifgl = malloc(sizeof(*ifgl), M_TEMP, M_NOWAIT)) == NULL) {
                IFNET_WUNLOCK();
                return (ENOMEM);
        }

        if ((ifgm = malloc(sizeof(*ifgm), M_TEMP, M_NOWAIT)) == NULL) {
                free(ifgl, M_TEMP);
                IFNET_WUNLOCK();
                return (ENOMEM);
        }

        CK_STAILQ_FOREACH(ifg, &V_ifg_head, ifg_next)
                if (!strcmp(ifg->ifg_group, groupname))
                        break;

        if (ifg == NULL) {
                if ((ifg = malloc(sizeof(*ifg), M_TEMP, M_NOWAIT)) == NULL) {
                        free(ifgl, M_TEMP);
                        free(ifgm, M_TEMP);
                        IFNET_WUNLOCK();
                        return (ENOMEM);
                }
                strlcpy(ifg->ifg_group, groupname, sizeof(ifg->ifg_group));
                ifg->ifg_refcnt = 0;
                CK_STAILQ_INIT(&ifg->ifg_members);
                CK_STAILQ_INSERT_TAIL(&V_ifg_head, ifg, ifg_next);
                new = 1;
        }

        ifg->ifg_refcnt++;
        ifgl->ifgl_group = ifg;
        ifgm->ifgm_ifp = ifp;

        IF_ADDR_WLOCK(ifp);
        CK_STAILQ_INSERT_TAIL(&ifg->ifg_members, ifgm, ifgm_next);
        CK_STAILQ_INSERT_TAIL(&ifp->if_groups, ifgl, ifgl_next);
        IF_ADDR_WUNLOCK(ifp);

        IFNET_WUNLOCK();

        if (new)
                EVENTHANDLER_INVOKE(group_attach_event, ifg);
        EVENTHANDLER_INVOKE(group_change_event, groupname);

        return (0);
}

/*
 * Helper function to remove a group out of an interface.  Expects the global
 * ifnet lock to be write-locked, and drops it before returning.
 */
static void
_if_delgroup_locked(struct ifnet *ifp, struct ifg_list *ifgl,
    const char *groupname)
{
        struct ifg_member *ifgm;
        bool freeifgl;

        IFNET_WLOCK_ASSERT();

        IF_ADDR_WLOCK(ifp);
        CK_STAILQ_REMOVE(&ifp->if_groups, ifgl, ifg_list, ifgl_next);
        IF_ADDR_WUNLOCK(ifp);

        CK_STAILQ_FOREACH(ifgm, &ifgl->ifgl_group->ifg_members, ifgm_next) {
                if (ifgm->ifgm_ifp == ifp) {
                        CK_STAILQ_REMOVE(&ifgl->ifgl_group->ifg_members, ifgm,
                            ifg_member, ifgm_next);
                        break;
                }
        }

        if (--ifgl->ifgl_group->ifg_refcnt == 0) {
                CK_STAILQ_REMOVE(&V_ifg_head, ifgl->ifgl_group, ifg_group,
                    ifg_next);
                freeifgl = true;
        } else {
                freeifgl = false;
        }
        IFNET_WUNLOCK();

        epoch_wait_preempt(net_epoch_preempt);
        if (freeifgl) {
                EVENTHANDLER_INVOKE(group_detach_event, ifgl->ifgl_group);
                free(ifgl->ifgl_group, M_TEMP);
        }
        free(ifgm, M_TEMP);
        free(ifgl, M_TEMP);

        EVENTHANDLER_INVOKE(group_change_event, groupname);
}

/*
 * Remove a group from an interface
 */
int
if_delgroup(struct ifnet *ifp, const char *groupname)
{
        struct ifg_list *ifgl;

        IFNET_WLOCK();
        CK_STAILQ_FOREACH(ifgl, &ifp->if_groups, ifgl_next)
                if (strcmp(ifgl->ifgl_group->ifg_group, groupname) == 0)
                        break;
        if (ifgl == NULL) {
                IFNET_WUNLOCK();
                return (ENOENT);
        }

        _if_delgroup_locked(ifp, ifgl, groupname);

        return (0);
}

/*
 * Remove an interface from all groups
 */
static void
if_delgroups(struct ifnet *ifp)
{
        struct ifg_list *ifgl;
        char groupname[IFNAMSIZ];

        IFNET_WLOCK();
        while ((ifgl = CK_STAILQ_FIRST(&ifp->if_groups)) != NULL) {
                strlcpy(groupname, ifgl->ifgl_group->ifg_group, IFNAMSIZ);
                _if_delgroup_locked(ifp, ifgl, groupname);
                IFNET_WLOCK();
        }
        IFNET_WUNLOCK();
}

static char *
ifgr_group_get(void *ifgrp)
{
        union ifgroupreq_union *ifgrup;

        ifgrup = ifgrp;
#ifdef COMPAT_FREEBSD32
        if (SV_CURPROC_FLAG(SV_ILP32))
                return (&ifgrup->ifgr32.ifgr_ifgru.ifgru_group[0]);
#endif
        return (&ifgrup->ifgr.ifgr_ifgru.ifgru_group[0]);
}

static struct ifg_req *
ifgr_groups_get(void *ifgrp)
{
        union ifgroupreq_union *ifgrup;

        ifgrup = ifgrp;
#ifdef COMPAT_FREEBSD32
        if (SV_CURPROC_FLAG(SV_ILP32))
                return ((struct ifg_req *)(uintptr_t)
                    ifgrup->ifgr32.ifgr_ifgru.ifgru_groups);
#endif
        return (ifgrup->ifgr.ifgr_ifgru.ifgru_groups);
}

/*
 * Stores all groups from an interface in memory pointed to by ifgr.
 */
static int
if_getgroup(struct ifgroupreq *ifgr, struct ifnet *ifp)
{
        int                      len, error;
        struct ifg_list         *ifgl;
        struct ifg_req           ifgrq, *ifgp;

        NET_EPOCH_ASSERT();

        if (ifgr->ifgr_len == 0) {
                CK_STAILQ_FOREACH(ifgl, &ifp->if_groups, ifgl_next)
                        ifgr->ifgr_len += sizeof(struct ifg_req);
                return (0);
        }

        len = ifgr->ifgr_len;
        ifgp = ifgr_groups_get(ifgr);
        /* XXX: wire */
        CK_STAILQ_FOREACH(ifgl, &ifp->if_groups, ifgl_next) {
                if (len < sizeof(ifgrq))
                        return (EINVAL);
                bzero(&ifgrq, sizeof ifgrq);
                strlcpy(ifgrq.ifgrq_group, ifgl->ifgl_group->ifg_group,
                    sizeof(ifgrq.ifgrq_group));
                if ((error = copyout(&ifgrq, ifgp, sizeof(struct ifg_req))))
                        return (error);
                len -= sizeof(ifgrq);
                ifgp++;
        }

        return (0);
}

/*
 * Stores all members of a group in memory pointed to by igfr
 */
static int
if_getgroupmembers(struct ifgroupreq *ifgr)
{
        struct ifg_group        *ifg;
        struct ifg_member       *ifgm;
        struct ifg_req           ifgrq, *ifgp;
        int                      len, error;

        IFNET_RLOCK();
        CK_STAILQ_FOREACH(ifg, &V_ifg_head, ifg_next)
                if (strcmp(ifg->ifg_group, ifgr->ifgr_name) == 0)
                        break;
        if (ifg == NULL) {
                IFNET_RUNLOCK();
                return (ENOENT);
        }

        if (ifgr->ifgr_len == 0) {
                CK_STAILQ_FOREACH(ifgm, &ifg->ifg_members, ifgm_next)
                        ifgr->ifgr_len += sizeof(ifgrq);
                IFNET_RUNLOCK();
                return (0);
        }

        len = ifgr->ifgr_len;
        ifgp = ifgr_groups_get(ifgr);
        CK_STAILQ_FOREACH(ifgm, &ifg->ifg_members, ifgm_next) {
                if (len < sizeof(ifgrq)) {
                        IFNET_RUNLOCK();
                        return (EINVAL);
                }
                bzero(&ifgrq, sizeof ifgrq);
                strlcpy(ifgrq.ifgrq_member, ifgm->ifgm_ifp->if_xname,
                    sizeof(ifgrq.ifgrq_member));
                if ((error = copyout(&ifgrq, ifgp, sizeof(struct ifg_req)))) {
                        IFNET_RUNLOCK();
                        return (error);
                }
                len -= sizeof(ifgrq);
                ifgp++;
        }
        IFNET_RUNLOCK();

        return (0);
}

/*
 * Return counter values from counter(9)s stored in ifnet.
 */
uint64_t
if_get_counter_default(struct ifnet *ifp, ift_counter cnt)
{

        KASSERT(cnt < IFCOUNTERS, ("%s: invalid cnt %d", __func__, cnt));

        return (counter_u64_fetch(ifp->if_counters[cnt]));
}

/*
 * Increase an ifnet counter. Usually used for counters shared
 * between the stack and a driver, but function supports them all.
 */
void
if_inc_counter(struct ifnet *ifp, ift_counter cnt, int64_t inc)
{

        KASSERT(cnt < IFCOUNTERS, ("%s: invalid cnt %d", __func__, cnt));

        counter_u64_add(ifp->if_counters[cnt], inc);
}

/*
 * Copy data from ifnet to userland API structure if_data.
 */
void
if_data_copy(struct ifnet *ifp, struct if_data *ifd)
{

        ifd->ifi_type = ifp->if_type;
        ifd->ifi_physical = 0;
        ifd->ifi_addrlen = ifp->if_addrlen;
        ifd->ifi_hdrlen = ifp->if_hdrlen;
        ifd->ifi_link_state = ifp->if_link_state;
        ifd->ifi_vhid = 0;
        ifd->ifi_datalen = sizeof(struct if_data);
        ifd->ifi_mtu = ifp->if_mtu;
        ifd->ifi_metric = ifp->if_metric;
        ifd->ifi_baudrate = ifp->if_baudrate;
        ifd->ifi_hwassist = ifp->if_hwassist;
        ifd->ifi_epoch = ifp->if_epoch;
        ifd->ifi_lastchange = ifp->if_lastchange;

        ifd->ifi_ipackets = ifp->if_get_counter(ifp, IFCOUNTER_IPACKETS);
        ifd->ifi_ierrors = ifp->if_get_counter(ifp, IFCOUNTER_IERRORS);
        ifd->ifi_opackets = ifp->if_get_counter(ifp, IFCOUNTER_OPACKETS);
        ifd->ifi_oerrors = ifp->if_get_counter(ifp, IFCOUNTER_OERRORS);
        ifd->ifi_collisions = ifp->if_get_counter(ifp, IFCOUNTER_COLLISIONS);
        ifd->ifi_ibytes = ifp->if_get_counter(ifp, IFCOUNTER_IBYTES);
        ifd->ifi_obytes = ifp->if_get_counter(ifp, IFCOUNTER_OBYTES);
        ifd->ifi_imcasts = ifp->if_get_counter(ifp, IFCOUNTER_IMCASTS);
        ifd->ifi_omcasts = ifp->if_get_counter(ifp, IFCOUNTER_OMCASTS);
        ifd->ifi_iqdrops = ifp->if_get_counter(ifp, IFCOUNTER_IQDROPS);
        ifd->ifi_oqdrops = ifp->if_get_counter(ifp, IFCOUNTER_OQDROPS);
        ifd->ifi_noproto = ifp->if_get_counter(ifp, IFCOUNTER_NOPROTO);
}

/*
 * Initialization, destruction and refcounting functions for ifaddrs.
 */
struct ifaddr *
ifa_alloc(size_t size, int flags)
{
        struct ifaddr *ifa;

        KASSERT(size >= sizeof(struct ifaddr),
            ("%s: invalid size %zu", __func__, size));

        ifa = malloc(size, M_IFADDR, M_ZERO | flags);
        if (ifa == NULL)
                return (NULL);

        if ((ifa->ifa_opackets = counter_u64_alloc(flags)) == NULL)
                goto fail;
        if ((ifa->ifa_ipackets = counter_u64_alloc(flags)) == NULL)
                goto fail;
        if ((ifa->ifa_obytes = counter_u64_alloc(flags)) == NULL)
                goto fail;
        if ((ifa->ifa_ibytes = counter_u64_alloc(flags)) == NULL)
                goto fail;

        refcount_init(&ifa->ifa_refcnt, 1);

        return (ifa);

fail:
        /* free(NULL) is okay */
        counter_u64_free(ifa->ifa_opackets);
        counter_u64_free(ifa->ifa_ipackets);
        counter_u64_free(ifa->ifa_obytes);
        counter_u64_free(ifa->ifa_ibytes);
        free(ifa, M_IFADDR);

        return (NULL);
}

void
ifa_ref(struct ifaddr *ifa)
{
        u_int old;

        old = refcount_acquire(&ifa->ifa_refcnt);
        KASSERT(old > 0, ("%s: ifa %p has 0 refs", __func__, ifa));
}

int
ifa_try_ref(struct ifaddr *ifa)
{

        NET_EPOCH_ASSERT();
        return (refcount_acquire_if_not_zero(&ifa->ifa_refcnt));
}

static void
ifa_destroy(epoch_context_t ctx)
{
        struct ifaddr *ifa;

        ifa = __containerof(ctx, struct ifaddr, ifa_epoch_ctx);
        counter_u64_free(ifa->ifa_opackets);
        counter_u64_free(ifa->ifa_ipackets);
        counter_u64_free(ifa->ifa_obytes);
        counter_u64_free(ifa->ifa_ibytes);
        free(ifa, M_IFADDR);
}

void
ifa_free(struct ifaddr *ifa)
{

        if (refcount_release(&ifa->ifa_refcnt))
                NET_EPOCH_CALL(ifa_destroy, &ifa->ifa_epoch_ctx);
}

/*
 * XXX: Because sockaddr_dl has deeper structure than the sockaddr
 * structs used to represent other address families, it is necessary
 * to perform a different comparison.
 */

#define sa_dl_equal(a1, a2)     \
        ((((const struct sockaddr_dl *)(a1))->sdl_len ==                \
         ((const struct sockaddr_dl *)(a2))->sdl_len) &&                \
         (bcmp(CLLADDR((const struct sockaddr_dl *)(a1)),               \
               CLLADDR((const struct sockaddr_dl *)(a2)),               \
               ((const struct sockaddr_dl *)(a1))->sdl_alen) == 0))

/*
 * Locate an interface based on a complete address.
 */
/*ARGSUSED*/
struct ifaddr *
ifa_ifwithaddr(const struct sockaddr *addr)
{
        struct ifnet *ifp;
        struct ifaddr *ifa;

        NET_EPOCH_ASSERT();

        CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
                CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                        if (ifa->ifa_addr->sa_family != addr->sa_family)
                                continue;
                        if (sa_equal(addr, ifa->ifa_addr)) {
                                goto done;
                        }
                        /* IP6 doesn't have broadcast */
                        if ((ifp->if_flags & IFF_BROADCAST) &&
                            ifa->ifa_broadaddr &&
                            ifa->ifa_broadaddr->sa_len != 0 &&
                            sa_equal(ifa->ifa_broadaddr, addr)) {
                                goto done;
                        }
                }
        }
        ifa = NULL;
done:
        return (ifa);
}

int
ifa_ifwithaddr_check(const struct sockaddr *addr)
{
        struct epoch_tracker et;
        int rc;

        NET_EPOCH_ENTER(et);
        rc = (ifa_ifwithaddr(addr) != NULL);
        NET_EPOCH_EXIT(et);
        return (rc);
}

/*
 * Locate an interface based on the broadcast address.
 */
/* ARGSUSED */
struct ifaddr *
ifa_ifwithbroadaddr(const struct sockaddr *addr, int fibnum)
{
        struct ifnet *ifp;
        struct ifaddr *ifa;

        NET_EPOCH_ASSERT();
        CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
                if ((fibnum != RT_ALL_FIBS) && (ifp->if_fib != fibnum))
                        continue;
                CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                        if (ifa->ifa_addr->sa_family != addr->sa_family)
                                continue;
                        if ((ifp->if_flags & IFF_BROADCAST) &&
                            ifa->ifa_broadaddr &&
                            ifa->ifa_broadaddr->sa_len != 0 &&
                            sa_equal(ifa->ifa_broadaddr, addr)) {
                                goto done;
                        }
                }
        }
        ifa = NULL;
done:
        return (ifa);
}

/*
 * Locate the point to point interface with a given destination address.
 */
/*ARGSUSED*/
struct ifaddr *
ifa_ifwithdstaddr(const struct sockaddr *addr, int fibnum)
{
        struct ifnet *ifp;
        struct ifaddr *ifa;

        NET_EPOCH_ASSERT();
        CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
                if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
                        continue;
                if ((fibnum != RT_ALL_FIBS) && (ifp->if_fib != fibnum))
                        continue;
                CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                        if (ifa->ifa_addr->sa_family != addr->sa_family)
                                continue;
                        if (ifa->ifa_dstaddr != NULL &&
                            sa_equal(addr, ifa->ifa_dstaddr)) {
                                goto done;
                        }
                }
        }
        ifa = NULL;
done:
        return (ifa);
}

/*
 * Find an interface on a specific network.  If many, choice
 * is most specific found.
 */
struct ifaddr *
ifa_ifwithnet(const struct sockaddr *addr, int ignore_ptp, int fibnum)
{
        struct ifnet *ifp;
        struct ifaddr *ifa;
        struct ifaddr *ifa_maybe = NULL;
        u_int af = addr->sa_family;
        const char *addr_data = addr->sa_data, *cplim;

        NET_EPOCH_ASSERT();
        /*
         * AF_LINK addresses can be looked up directly by their index number,
         * so do that if we can.
         */
        if (af == AF_LINK) {
            const struct sockaddr_dl *sdl = (const struct sockaddr_dl *)addr;
            if (sdl->sdl_index && sdl->sdl_index <= V_if_index)
                return (ifaddr_byindex(sdl->sdl_index));
        }

        /*
         * Scan though each interface, looking for ones that have addresses
         * in this address family and the requested fib.
         */
        CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
                if ((fibnum != RT_ALL_FIBS) && (ifp->if_fib != fibnum))
                        continue;
                CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                        const char *cp, *cp2, *cp3;

                        if (ifa->ifa_addr->sa_family != af)
next:                           continue;
                        if (af == AF_INET && 
                            ifp->if_flags & IFF_POINTOPOINT && !ignore_ptp) {
                                /*
                                 * This is a bit broken as it doesn't
                                 * take into account that the remote end may
                                 * be a single node in the network we are
                                 * looking for.
                                 * The trouble is that we don't know the
                                 * netmask for the remote end.
                                 */
                                if (ifa->ifa_dstaddr != NULL &&
                                    sa_equal(addr, ifa->ifa_dstaddr)) {
                                        goto done;
                                }
                        } else {
                                /*
                                 * Scan all the bits in the ifa's address.
                                 * If a bit dissagrees with what we are
                                 * looking for, mask it with the netmask
                                 * to see if it really matters.
                                 * (A byte at a time)
                                 */
                                if (ifa->ifa_netmask == 0)
                                        continue;
                                cp = addr_data;
                                cp2 = ifa->ifa_addr->sa_data;
                                cp3 = ifa->ifa_netmask->sa_data;
                                cplim = ifa->ifa_netmask->sa_len
                                        + (char *)ifa->ifa_netmask;
                                while (cp3 < cplim)
                                        if ((*cp++ ^ *cp2++) & *cp3++)
                                                goto next; /* next address! */
                                /*
                                 * If the netmask of what we just found
                                 * is more specific than what we had before
                                 * (if we had one), or if the virtual status
                                 * of new prefix is better than of the old one,
                                 * then remember the new one before continuing
                                 * to search for an even better one.
                                 */
                                if (ifa_maybe == NULL ||
                                    ifa_preferred(ifa_maybe, ifa) ||
                                    rn_refines((caddr_t)ifa->ifa_netmask,
                                    (caddr_t)ifa_maybe->ifa_netmask)) {
                                        ifa_maybe = ifa;
                                }
                        }
                }
        }
        ifa = ifa_maybe;
        ifa_maybe = NULL;
done:
        return (ifa);
}

/*
 * Find an interface address specific to an interface best matching
 * a given address.
 */
struct ifaddr *
ifaof_ifpforaddr(const struct sockaddr *addr, struct ifnet *ifp)
{
        struct ifaddr *ifa;
        const char *cp, *cp2, *cp3;
        char *cplim;
        struct ifaddr *ifa_maybe = NULL;
        u_int af = addr->sa_family;

        if (af >= AF_MAX)
                return (NULL);

        NET_EPOCH_ASSERT();
        CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                if (ifa->ifa_addr->sa_family != af)
                        continue;
                if (ifa_maybe == NULL)
                        ifa_maybe = ifa;
                if (ifa->ifa_netmask == 0) {
                        if (sa_equal(addr, ifa->ifa_addr) ||
                            (ifa->ifa_dstaddr &&
                            sa_equal(addr, ifa->ifa_dstaddr)))
                                goto done;
                        continue;
                }
                if (ifp->if_flags & IFF_POINTOPOINT) {
                        if (sa_equal(addr, ifa->ifa_dstaddr))
                                goto done;
                } else {
                        cp = addr->sa_data;
                        cp2 = ifa->ifa_addr->sa_data;
                        cp3 = ifa->ifa_netmask->sa_data;
                        cplim = ifa->ifa_netmask->sa_len + (char *)ifa->ifa_netmask;
                        for (; cp3 < cplim; cp3++)
                                if ((*cp++ ^ *cp2++) & *cp3)
                                        break;
                        if (cp3 == cplim)
                                goto done;
                }
        }
        ifa = ifa_maybe;
done:
        return (ifa);
}

/*
 * See whether new ifa is better than current one:
 * 1) A non-virtual one is preferred over virtual.
 * 2) A virtual in master state preferred over any other state.
 *
 * Used in several address selecting functions.
 */
int
ifa_preferred(struct ifaddr *cur, struct ifaddr *next)
{

        return (cur->ifa_carp && (!next->ifa_carp ||
            ((*carp_master_p)(next) && !(*carp_master_p)(cur))));
}

struct sockaddr_dl *
link_alloc_sdl(size_t size, int flags)
{

        return (malloc(size, M_TEMP, flags));
}

void
link_free_sdl(struct sockaddr *sa)
{
        free(sa, M_TEMP);
}

/*
 * Fills in given sdl with interface basic info.
 * Returns pointer to filled sdl.
 */
struct sockaddr_dl *
link_init_sdl(struct ifnet *ifp, struct sockaddr *paddr, u_char iftype)
{
        struct sockaddr_dl *sdl;

        sdl = (struct sockaddr_dl *)paddr;
        memset(sdl, 0, sizeof(struct sockaddr_dl));
        sdl->sdl_len = sizeof(struct sockaddr_dl);
        sdl->sdl_family = AF_LINK;
        sdl->sdl_index = ifp->if_index;
        sdl->sdl_type = iftype;

        return (sdl);
}

/*
 * Mark an interface down and notify protocols of
 * the transition.
 */
static void
if_unroute(struct ifnet *ifp, int flag, int fam)
{
        struct ifaddr *ifa;
        struct epoch_tracker et;

        KASSERT(flag == IFF_UP, ("if_unroute: flag != IFF_UP"));

        ifp->if_flags &= ~flag;
        getmicrotime(&ifp->if_lastchange);
        NET_EPOCH_ENTER(et);
        CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
                if (fam == PF_UNSPEC || (fam == ifa->ifa_addr->sa_family))
                        pfctlinput(PRC_IFDOWN, ifa->ifa_addr);
        NET_EPOCH_EXIT(et);
        ifp->if_qflush(ifp);

        if (ifp->if_carp)
                (*carp_linkstate_p)(ifp);
        rt_ifmsg(ifp);
}

/*
 * Mark an interface up and notify protocols of
 * the transition.
 */
static void
if_route(struct ifnet *ifp, int flag, int fam)
{
        struct ifaddr *ifa;
        struct epoch_tracker et;

        KASSERT(flag == IFF_UP, ("if_route: flag != IFF_UP"));

        ifp->if_flags |= flag;
        getmicrotime(&ifp->if_lastchange);
        NET_EPOCH_ENTER(et);
        CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
                if (fam == PF_UNSPEC || (fam == ifa->ifa_addr->sa_family))
                        pfctlinput(PRC_IFUP, ifa->ifa_addr);
        NET_EPOCH_EXIT(et);
        if (ifp->if_carp)
                (*carp_linkstate_p)(ifp);
        rt_ifmsg(ifp);
#ifdef INET6
        in6_if_up(ifp);
#endif
}

void    (*vlan_link_state_p)(struct ifnet *);   /* XXX: private from if_vlan */
void    (*vlan_trunk_cap_p)(struct ifnet *);            /* XXX: private from if_vlan */
struct ifnet *(*vlan_trunkdev_p)(struct ifnet *);
struct  ifnet *(*vlan_devat_p)(struct ifnet *, uint16_t);
int     (*vlan_tag_p)(struct ifnet *, uint16_t *);
int     (*vlan_pcp_p)(struct ifnet *, uint16_t *);
int     (*vlan_setcookie_p)(struct ifnet *, void *);
void    *(*vlan_cookie_p)(struct ifnet *);

/*
 * Handle a change in the interface link state. To avoid LORs
 * between driver lock and upper layer locks, as well as possible
 * recursions, we post event to taskqueue, and all job
 * is done in static do_link_state_change().
 */
void
if_link_state_change(struct ifnet *ifp, int link_state)
{
        /* Return if state hasn't changed. */
        if (ifp->if_link_state == link_state)
                return;

        ifp->if_link_state = link_state;

        /* XXXGL: reference ifp? */
        taskqueue_enqueue(taskqueue_swi, &ifp->if_linktask);
}

static void
do_link_state_change(void *arg, int pending)
{
        struct ifnet *ifp;
        int link_state;

        ifp = arg;
        link_state = ifp->if_link_state;

        CURVNET_SET(ifp->if_vnet);
        rt_ifmsg(ifp);
        if (ifp->if_vlantrunk != NULL)
                (*vlan_link_state_p)(ifp);

        if ((ifp->if_type == IFT_ETHER || ifp->if_type == IFT_L2VLAN) &&
            ifp->if_l2com != NULL)
                (*ng_ether_link_state_p)(ifp, link_state);
        if (ifp->if_carp)
                (*carp_linkstate_p)(ifp);
        if (ifp->if_bridge)
                ifp->if_bridge_linkstate(ifp);
        if (ifp->if_lagg)
                (*lagg_linkstate_p)(ifp, link_state);

        if (IS_DEFAULT_VNET(curvnet))
                devctl_notify("IFNET", ifp->if_xname,
                    (link_state == LINK_STATE_UP) ? "LINK_UP" : "LINK_DOWN",
                    NULL);
        if (pending > 1)
                if_printf(ifp, "%d link states coalesced\n", pending);
        if (log_link_state_change)
                if_printf(ifp, "link state changed to %s\n",
                    (link_state == LINK_STATE_UP) ? "UP" : "DOWN" );
        EVENTHANDLER_INVOKE(ifnet_link_event, ifp, link_state);
        CURVNET_RESTORE();
}

/*
 * Mark an interface down and notify protocols of
 * the transition.
 */
void
if_down(struct ifnet *ifp)
{

        EVENTHANDLER_INVOKE(ifnet_event, ifp, IFNET_EVENT_DOWN);
        if_unroute(ifp, IFF_UP, AF_UNSPEC);
}

/*
 * Mark an interface up and notify protocols of
 * the transition.
 */
void
if_up(struct ifnet *ifp)
{

        if_route(ifp, IFF_UP, AF_UNSPEC);
        EVENTHANDLER_INVOKE(ifnet_event, ifp, IFNET_EVENT_UP);
}

/*
 * Flush an interface queue.
 */
void
if_qflush(struct ifnet *ifp)
{
        struct mbuf *m, *n;
        struct ifaltq *ifq;

        ifq = &ifp->if_snd;
        IFQ_LOCK(ifq);
#ifdef ALTQ
        if (ALTQ_IS_ENABLED(ifq))
                ALTQ_PURGE(ifq);
#endif
        n = ifq->ifq_head;
        while ((m = n) != NULL) {
                n = m->m_nextpkt;
                m_freem(m);
        }
        ifq->ifq_head = 0;
        ifq->ifq_tail = 0;
        ifq->ifq_len = 0;
        IFQ_UNLOCK(ifq);
}

/*
 * Map interface name to interface structure pointer, with or without
 * returning a reference.
 */
struct ifnet *
ifunit_ref(const char *name)
{
        struct epoch_tracker et;
        struct ifnet *ifp;

        NET_EPOCH_ENTER(et);
        CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
                if (strncmp(name, ifp->if_xname, IFNAMSIZ) == 0 &&
                    !(ifp->if_flags & IFF_DYING))
                        break;
        }
        if (ifp != NULL)
                if_ref(ifp);
        NET_EPOCH_EXIT(et);
        return (ifp);
}

struct ifnet *
ifunit(const char *name)
{
        struct epoch_tracker et;
        struct ifnet *ifp;

        NET_EPOCH_ENTER(et);
        CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
                if (strncmp(name, ifp->if_xname, IFNAMSIZ) == 0)
                        break;
        }
        NET_EPOCH_EXIT(et);
        return (ifp);
}

void *
ifr_buffer_get_buffer(void *data)
{
        union ifreq_union *ifrup;

        ifrup = data;
#ifdef COMPAT_FREEBSD32
        if (SV_CURPROC_FLAG(SV_ILP32))
                return ((void *)(uintptr_t)
                    ifrup->ifr32.ifr_ifru.ifru_buffer.buffer);
#endif
        return (ifrup->ifr.ifr_ifru.ifru_buffer.buffer);
}

static void
ifr_buffer_set_buffer_null(void *data)
{
        union ifreq_union *ifrup;

        ifrup = data;
#ifdef COMPAT_FREEBSD32
        if (SV_CURPROC_FLAG(SV_ILP32))
                ifrup->ifr32.ifr_ifru.ifru_buffer.buffer = 0;
        else
#endif
                ifrup->ifr.ifr_ifru.ifru_buffer.buffer = NULL;
}

size_t
ifr_buffer_get_length(void *data)
{
        union ifreq_union *ifrup;

        ifrup = data;
#ifdef COMPAT_FREEBSD32
        if (SV_CURPROC_FLAG(SV_ILP32))
                return (ifrup->ifr32.ifr_ifru.ifru_buffer.length);
#endif
        return (ifrup->ifr.ifr_ifru.ifru_buffer.length);
}

static void
ifr_buffer_set_length(void *data, size_t len)
{
        union ifreq_union *ifrup;

        ifrup = data;
#ifdef COMPAT_FREEBSD32
        if (SV_CURPROC_FLAG(SV_ILP32))
                ifrup->ifr32.ifr_ifru.ifru_buffer.length = len;
        else
#endif
                ifrup->ifr.ifr_ifru.ifru_buffer.length = len;
}

void *
ifr_data_get_ptr(void *ifrp)
{
        union ifreq_union *ifrup;

        ifrup = ifrp;
#ifdef COMPAT_FREEBSD32
        if (SV_CURPROC_FLAG(SV_ILP32))
                return ((void *)(uintptr_t)
                    ifrup->ifr32.ifr_ifru.ifru_data);
#endif
                return (ifrup->ifr.ifr_ifru.ifru_data);
}

/*
 * Hardware specific interface ioctls.
 */
int
ifhwioctl(u_long cmd, struct ifnet *ifp, caddr_t data, struct thread *td)
{
        struct ifreq *ifr;
        int error = 0, do_ifup = 0;
        int new_flags, temp_flags;
        size_t namelen, onamelen;
        size_t descrlen;
        char *descrbuf, *odescrbuf;
        char new_name[IFNAMSIZ];
        struct ifaddr *ifa;
        struct sockaddr_dl *sdl;

        ifr = (struct ifreq *)data;
        switch (cmd) {
        case SIOCGIFINDEX:
                ifr->ifr_index = ifp->if_index;
                break;

        case SIOCGIFFLAGS:
                temp_flags = ifp->if_flags | ifp->if_drv_flags;
                ifr->ifr_flags = temp_flags & 0xffff;
                ifr->ifr_flagshigh = temp_flags >> 16;
                break;

        case SIOCGIFCAP:
                ifr->ifr_reqcap = ifp->if_capabilities;
                ifr->ifr_curcap = ifp->if_capenable;
                break;

        case SIOCGIFDATA:
        {
                struct if_data ifd;

                /* Ensure uninitialised padding is not leaked. */
                memset(&ifd, 0, sizeof(ifd));

                if_data_copy(ifp, &ifd);
                error = copyout(&ifd, ifr_data_get_ptr(ifr), sizeof(ifd));
                break;
        }

#ifdef MAC
        case SIOCGIFMAC:
                error = mac_ifnet_ioctl_get(td->td_ucred, ifr, ifp);
                break;
#endif

        case SIOCGIFMETRIC:
                ifr->ifr_metric = ifp->if_metric;
                break;

        case SIOCGIFMTU:
                ifr->ifr_mtu = ifp->if_mtu;
                break;

        case SIOCGIFPHYS:
                /* XXXGL: did this ever worked? */
                ifr->ifr_phys = 0;
                break;

        case SIOCGIFDESCR:
                error = 0;
                sx_slock(&ifdescr_sx);
                if (ifp->if_description == NULL)
                        error = ENOMSG;
                else {
                        /* space for terminating nul */
                        descrlen = strlen(ifp->if_description) + 1;
                        if (ifr_buffer_get_length(ifr) < descrlen)
                                ifr_buffer_set_buffer_null(ifr);
                        else
                                error = copyout(ifp->if_description,
                                    ifr_buffer_get_buffer(ifr), descrlen);
                        ifr_buffer_set_length(ifr, descrlen);
                }
                sx_sunlock(&ifdescr_sx);
                break;

        case SIOCSIFDESCR:
                error = priv_check(td, PRIV_NET_SETIFDESCR);
                if (error)
                        return (error);

                /*
                 * Copy only (length-1) bytes to make sure that
                 * if_description is always nul terminated.  The
                 * length parameter is supposed to count the
                 * terminating nul in.
                 */
                if (ifr_buffer_get_length(ifr) > ifdescr_maxlen)
                        return (ENAMETOOLONG);
                else if (ifr_buffer_get_length(ifr) == 0)
                        descrbuf = NULL;
                else {
                        descrbuf = malloc(ifr_buffer_get_length(ifr),
                            M_IFDESCR, M_WAITOK | M_ZERO);
                        error = copyin(ifr_buffer_get_buffer(ifr), descrbuf,
                            ifr_buffer_get_length(ifr) - 1);
                        if (error) {
                                free(descrbuf, M_IFDESCR);
                                break;
                        }
                }

                sx_xlock(&ifdescr_sx);
                odescrbuf = ifp->if_description;
                ifp->if_description = descrbuf;
                sx_xunlock(&ifdescr_sx);

                getmicrotime(&ifp->if_lastchange);
                free(odescrbuf, M_IFDESCR);
                break;

        case SIOCGIFFIB:
                ifr->ifr_fib = ifp->if_fib;
                break;

        case SIOCSIFFIB:
                error = priv_check(td, PRIV_NET_SETIFFIB);
                if (error)
                        return (error);
                if (ifr->ifr_fib >= rt_numfibs)
                        return (EINVAL);

                ifp->if_fib = ifr->ifr_fib;
                break;

        case SIOCSIFFLAGS:
                error = priv_check(td, PRIV_NET_SETIFFLAGS);
                if (error)
                        return (error);
                /*
                 * Currently, no driver owned flags pass the IFF_CANTCHANGE
                 * check, so we don't need special handling here yet.
                 */
                new_flags = (ifr->ifr_flags & 0xffff) |
                    (ifr->ifr_flagshigh << 16);
                if (ifp->if_flags & IFF_UP &&
                    (new_flags & IFF_UP) == 0) {
                        if_down(ifp);
                } else if (new_flags & IFF_UP &&
                    (ifp->if_flags & IFF_UP) == 0) {
                        do_ifup = 1;
                }
                /* See if permanently promiscuous mode bit is about to flip */
                if ((ifp->if_flags ^ new_flags) & IFF_PPROMISC) {
                        if (new_flags & IFF_PPROMISC)
                                ifp->if_flags |= IFF_PROMISC;
                        else if (ifp->if_pcount == 0)
                                ifp->if_flags &= ~IFF_PROMISC;
                        if (log_promisc_mode_change)
                                if_printf(ifp, "permanently promiscuous mode %s\n",
                                    ((new_flags & IFF_PPROMISC) ?
                                     "enabled" : "disabled"));
                }
                ifp->if_flags = (ifp->if_flags & IFF_CANTCHANGE) |
                        (new_flags &~ IFF_CANTCHANGE);
                if (ifp->if_ioctl) {
                        (void) (*ifp->if_ioctl)(ifp, cmd, data);
                }
                if (do_ifup)
                        if_up(ifp);
                getmicrotime(&ifp->if_lastchange);
                break;

        case SIOCSIFCAP:
                error = priv_check(td, PRIV_NET_SETIFCAP);
                if (error)
                        return (error);
                if (ifp->if_ioctl == NULL)
                        return (EOPNOTSUPP);
                if (ifr->ifr_reqcap & ~ifp->if_capabilities)
                        return (EINVAL);
                error = (*ifp->if_ioctl)(ifp, cmd, data);
                if (error == 0)
                        getmicrotime(&ifp->if_lastchange);
                break;

#ifdef MAC
        case SIOCSIFMAC:
                error = mac_ifnet_ioctl_set(td->td_ucred, ifr, ifp);
                break;
#endif

        case SIOCSIFNAME:
                error = priv_check(td, PRIV_NET_SETIFNAME);
                if (error)
                        return (error);
                error = copyinstr(ifr_data_get_ptr(ifr), new_name, IFNAMSIZ,
                    NULL);
                if (error != 0)
                        return (error);
                if (new_name[0] == '\0')
                        return (EINVAL);
                if (strcmp(new_name, ifp->if_xname) == 0)
                        break;
                if (ifunit(new_name) != NULL)
                        return (EEXIST);

                /*
                 * XXX: Locking.  Nothing else seems to lock if_flags,
                 * and there are numerous other races with the
                 * ifunit() checks not being atomic with namespace
                 * changes (renames, vmoves, if_attach, etc).
                 */
                ifp->if_flags |= IFF_RENAMING;
                
                /* Announce the departure of the interface. */
                rt_ifannouncemsg(ifp, IFAN_DEPARTURE);
                EVENTHANDLER_INVOKE(ifnet_departure_event, ifp);

                if_printf(ifp, "changing name to '%s'\n", new_name);

                IF_ADDR_WLOCK(ifp);
                strlcpy(ifp->if_xname, new_name, sizeof(ifp->if_xname));
                ifa = ifp->if_addr;
                sdl = (struct sockaddr_dl *)ifa->ifa_addr;
                namelen = strlen(new_name);
                onamelen = sdl->sdl_nlen;
                /*
                 * Move the address if needed.  This is safe because we
                 * allocate space for a name of length IFNAMSIZ when we
                 * create this in if_attach().
                 */
                if (namelen != onamelen) {
                        bcopy(sdl->sdl_data + onamelen,
                            sdl->sdl_data + namelen, sdl->sdl_alen);
                }
                bcopy(new_name, sdl->sdl_data, namelen);
                sdl->sdl_nlen = namelen;
                sdl = (struct sockaddr_dl *)ifa->ifa_netmask;
                bzero(sdl->sdl_data, onamelen);
                while (namelen != 0)
                        sdl->sdl_data[--namelen] = 0xff;
                IF_ADDR_WUNLOCK(ifp);

                EVENTHANDLER_INVOKE(ifnet_arrival_event, ifp);
                /* Announce the return of the interface. */
                rt_ifannouncemsg(ifp, IFAN_ARRIVAL);

                ifp->if_flags &= ~IFF_RENAMING;
                break;

#ifdef VIMAGE
        case SIOCSIFVNET:
                error = priv_check(td, PRIV_NET_SETIFVNET);
                if (error)
                        return (error);
                error = if_vmove_loan(td, ifp, ifr->ifr_name, ifr->ifr_jid);
                break;
#endif

        case SIOCSIFMETRIC:
                error = priv_check(td, PRIV_NET_SETIFMETRIC);
                if (error)
                        return (error);
                ifp->if_metric = ifr->ifr_metric;
                getmicrotime(&ifp->if_lastchange);
                break;

        case SIOCSIFPHYS:
                error = priv_check(td, PRIV_NET_SETIFPHYS);
                if (error)
                        return (error);
                if (ifp->if_ioctl == NULL)
                        return (EOPNOTSUPP);
                error = (*ifp->if_ioctl)(ifp, cmd, data);
                if (error == 0)
                        getmicrotime(&ifp->if_lastchange);
                break;

        case SIOCSIFMTU:
        {
                u_long oldmtu = ifp->if_mtu;

                error = priv_check(td, PRIV_NET_SETIFMTU);
                if (error)
                        return (error);
                if (ifr->ifr_mtu < IF_MINMTU || ifr->ifr_mtu > IF_MAXMTU)
                        return (EINVAL);
                if (ifp->if_ioctl == NULL)
                        return (EOPNOTSUPP);
                error = (*ifp->if_ioctl)(ifp, cmd, data);
                if (error == 0) {
                        getmicrotime(&ifp->if_lastchange);
                        rt_ifmsg(ifp);
#ifdef INET
                        DEBUGNET_NOTIFY_MTU(ifp);
#endif
                }
                /*
                 * If the link MTU changed, do network layer specific procedure.
                 */
                if (ifp->if_mtu != oldmtu) {
#ifdef INET6
                        nd6_setmtu(ifp);
#endif
                        rt_updatemtu(ifp);
                }
                break;
        }

        case SIOCADDMULTI:
        case SIOCDELMULTI:
                if (cmd == SIOCADDMULTI)
                        error = priv_check(td, PRIV_NET_ADDMULTI);
                else
                        error = priv_check(td, PRIV_NET_DELMULTI);
                if (error)
                        return (error);

                /* Don't allow group membership on non-multicast interfaces. */
                if ((ifp->if_flags & IFF_MULTICAST) == 0)
                        return (EOPNOTSUPP);

                /* Don't let users screw up protocols' entries. */
                if (ifr->ifr_addr.sa_family != AF_LINK)
                        return (EINVAL);

                if (cmd == SIOCADDMULTI) {
                        struct epoch_tracker et;
                        struct ifmultiaddr *ifma;

                        /*
                         * Userland is only permitted to join groups once
                         * via the if_addmulti() KPI, because it cannot hold
                         * struct ifmultiaddr * between calls. It may also
                         * lose a race while we check if the membership
                         * already exists.
                         */
                        NET_EPOCH_ENTER(et);
                        ifma = if_findmulti(ifp, &ifr->ifr_addr);
                        NET_EPOCH_EXIT(et);
                        if (ifma != NULL)
                                error = EADDRINUSE;
                        else
                                error = if_addmulti(ifp, &ifr->ifr_addr, &ifma);
                } else {
                        error = if_delmulti(ifp, &ifr->ifr_addr);
                }
                if (error == 0)
                        getmicrotime(&ifp->if_lastchange);
                break;

        case SIOCSIFPHYADDR:
        case SIOCDIFPHYADDR:
#ifdef INET6
        case SIOCSIFPHYADDR_IN6:
#endif
        case SIOCSIFMEDIA:
        case SIOCSIFGENERIC:
                error = priv_check(td, PRIV_NET_HWIOCTL);
                if (error)
                        return (error);
                if (ifp->if_ioctl == NULL)
                        return (EOPNOTSUPP);
                error = (*ifp->if_ioctl)(ifp, cmd, data);
                if (error == 0)
                        getmicrotime(&ifp->if_lastchange);
                break;

        case SIOCGIFSTATUS:
        case SIOCGIFPSRCADDR:
        case SIOCGIFPDSTADDR:
        case SIOCGIFMEDIA:
        case SIOCGIFXMEDIA:
        case SIOCGIFGENERIC:
        case SIOCGIFRSSKEY:
        case SIOCGIFRSSHASH:
        case SIOCGIFDOWNREASON:
                if (ifp->if_ioctl == NULL)
                        return (EOPNOTSUPP);
                error = (*ifp->if_ioctl)(ifp, cmd, data);
                break;

        case SIOCSIFLLADDR:
                error = priv_check(td, PRIV_NET_SETLLADDR);
                if (error)
                        return (error);
                error = if_setlladdr(ifp,
                    ifr->ifr_addr.sa_data, ifr->ifr_addr.sa_len);
                break;

        case SIOCGHWADDR:
                error = if_gethwaddr(ifp, ifr);
                break;

        case CASE_IOC_IFGROUPREQ(SIOCAIFGROUP):
                error = priv_check(td, PRIV_NET_ADDIFGROUP);
                if (error)
                        return (error);
                if ((error = if_addgroup(ifp,
                    ifgr_group_get((struct ifgroupreq *)data))))
                        return (error);
                break;

        case CASE_IOC_IFGROUPREQ(SIOCGIFGROUP):
        {
                struct epoch_tracker et;

                NET_EPOCH_ENTER(et);
                error = if_getgroup((struct ifgroupreq *)data, ifp);
                NET_EPOCH_EXIT(et);
                break;
        }

        case CASE_IOC_IFGROUPREQ(SIOCDIFGROUP):
                error = priv_check(td, PRIV_NET_DELIFGROUP);
                if (error)
                        return (error);
                if ((error = if_delgroup(ifp,
                    ifgr_group_get((struct ifgroupreq *)data))))
                        return (error);
                break;

        default:
                error = ENOIOCTL;
                break;
        }
        return (error);
}

#ifdef COMPAT_FREEBSD32
struct ifconf32 {
        int32_t ifc_len;
        union {
                uint32_t        ifcu_buf;
                uint32_t        ifcu_req;
        } ifc_ifcu;
};
#define SIOCGIFCONF32   _IOWR('i', 36, struct ifconf32)
#endif

#ifdef COMPAT_FREEBSD32
static void
ifmr_init(struct ifmediareq *ifmr, caddr_t data)
{
        struct ifmediareq32 *ifmr32;

        ifmr32 = (struct ifmediareq32 *)data;
        memcpy(ifmr->ifm_name, ifmr32->ifm_name,
            sizeof(ifmr->ifm_name));
        ifmr->ifm_current = ifmr32->ifm_current;
        ifmr->ifm_mask = ifmr32->ifm_mask;
        ifmr->ifm_status = ifmr32->ifm_status;
        ifmr->ifm_active = ifmr32->ifm_active;
        ifmr->ifm_count = ifmr32->ifm_count;
        ifmr->ifm_ulist = (int *)(uintptr_t)ifmr32->ifm_ulist;
}

static void
ifmr_update(const struct ifmediareq *ifmr, caddr_t data)
{
        struct ifmediareq32 *ifmr32;

        ifmr32 = (struct ifmediareq32 *)data;
        ifmr32->ifm_current = ifmr->ifm_current;
        ifmr32->ifm_mask = ifmr->ifm_mask;
        ifmr32->ifm_status = ifmr->ifm_status;
        ifmr32->ifm_active = ifmr->ifm_active;
        ifmr32->ifm_count = ifmr->ifm_count;
}
#endif

/*
 * Interface ioctls.
 */
int
ifioctl(struct socket *so, u_long cmd, caddr_t data, struct thread *td)
{
#ifdef COMPAT_FREEBSD32
        caddr_t saved_data = NULL;
        struct ifmediareq ifmr;
        struct ifmediareq *ifmrp = NULL;
#endif
        struct ifnet *ifp;
        struct ifreq *ifr;
        int error;
        int oif_flags;
#ifdef VIMAGE
        bool shutdown;
#endif

        CURVNET_SET(so->so_vnet);
#ifdef VIMAGE
        /* Make sure the VNET is stable. */
        shutdown = VNET_IS_SHUTTING_DOWN(so->so_vnet);
        if (shutdown) {
                CURVNET_RESTORE();
                return (EBUSY);
        }
#endif

        switch (cmd) {
        case SIOCGIFCONF:
                error = ifconf(cmd, data);
                goto out_noref;

#ifdef COMPAT_FREEBSD32
        case SIOCGIFCONF32:
                {
                        struct ifconf32 *ifc32;
                        struct ifconf ifc;

                        ifc32 = (struct ifconf32 *)data;
                        ifc.ifc_len = ifc32->ifc_len;
                        ifc.ifc_buf = PTRIN(ifc32->ifc_buf);

                        error = ifconf(SIOCGIFCONF, (void *)&ifc);
                        if (error == 0)
                                ifc32->ifc_len = ifc.ifc_len;
                        goto out_noref;
                }
#endif
        }

#ifdef COMPAT_FREEBSD32
        switch (cmd) {
        case SIOCGIFMEDIA32:
        case SIOCGIFXMEDIA32:
                ifmrp = &ifmr;
                ifmr_init(ifmrp, data);
                cmd = _IOC_NEWTYPE(cmd, struct ifmediareq);
                saved_data = data;
                data = (caddr_t)ifmrp;
        }
#endif

        ifr = (struct ifreq *)data;
        switch (cmd) {
#ifdef VIMAGE
        case SIOCSIFRVNET:
                error = priv_check(td, PRIV_NET_SETIFVNET);
                if (error == 0)
                        error = if_vmove_reclaim(td, ifr->ifr_name,
                            ifr->ifr_jid);
                goto out_noref;
#endif
        case SIOCIFCREATE:
        case SIOCIFCREATE2:
                error = priv_check(td, PRIV_NET_IFCREATE);
                if (error == 0)
                        error = if_clone_create(ifr->ifr_name,
                            sizeof(ifr->ifr_name), cmd == SIOCIFCREATE2 ?
                            ifr_data_get_ptr(ifr) : NULL);
                goto out_noref;
        case SIOCIFDESTROY:
                error = priv_check(td, PRIV_NET_IFDESTROY);

                if (error == 0) {
                        sx_xlock(&ifnet_detach_sxlock);
                        error = if_clone_destroy(ifr->ifr_name);
                        sx_xunlock(&ifnet_detach_sxlock);
                }
                goto out_noref;

        case SIOCIFGCLONERS:
                error = if_clone_list((struct if_clonereq *)data);
                goto out_noref;

        case CASE_IOC_IFGROUPREQ(SIOCGIFGMEMB):
                error = if_getgroupmembers((struct ifgroupreq *)data);
                goto out_noref;

#if defined(INET) || defined(INET6)
        case SIOCSVH:
        case SIOCGVH:
                if (carp_ioctl_p == NULL)
                        error = EPROTONOSUPPORT;
                else
                        error = (*carp_ioctl_p)(ifr, cmd, td);
                goto out_noref;
#endif
        }

        ifp = ifunit_ref(ifr->ifr_name);
        if (ifp == NULL) {
                error = ENXIO;
                goto out_noref;
        }

        error = ifhwioctl(cmd, ifp, data, td);
        if (error != ENOIOCTL)
                goto out_ref;

        oif_flags = ifp->if_flags;
        if (so->so_proto == NULL) {
                error = EOPNOTSUPP;
                goto out_ref;
        }

        /*
         * Pass the request on to the socket control method, and if the
         * latter returns EOPNOTSUPP, directly to the interface.
         *
         * Make an exception for the legacy SIOCSIF* requests.  Drivers
         * trust SIOCSIFADDR et al to come from an already privileged
         * layer, and do not perform any credentials checks or input
         * validation.
         */
        error = ((*so->so_proto->pr_usrreqs->pru_control)(so, cmd, data,
            ifp, td));
        if (error == EOPNOTSUPP && ifp != NULL && ifp->if_ioctl != NULL &&
            cmd != SIOCSIFADDR && cmd != SIOCSIFBRDADDR &&
            cmd != SIOCSIFDSTADDR && cmd != SIOCSIFNETMASK)
                error = (*ifp->if_ioctl)(ifp, cmd, data);

        if ((oif_flags ^ ifp->if_flags) & IFF_UP) {
#ifdef INET6
                if (ifp->if_flags & IFF_UP)
                        in6_if_up(ifp);
#endif
        }

out_ref:
        if_rele(ifp);
out_noref:
#ifdef COMPAT_FREEBSD32
        if (ifmrp != NULL) {
                KASSERT((cmd == SIOCGIFMEDIA || cmd == SIOCGIFXMEDIA),
                    ("ifmrp non-NULL, but cmd is not an ifmedia req 0x%lx",
                     cmd));
                data = saved_data;
                ifmr_update(ifmrp, data);
        }
#endif
        CURVNET_RESTORE();
        return (error);
}

/*
 * The code common to handling reference counted flags,
 * e.g., in ifpromisc() and if_allmulti().
 * The "pflag" argument can specify a permanent mode flag to check,
 * such as IFF_PPROMISC for promiscuous mode; should be 0 if none.
 *
 * Only to be used on stack-owned flags, not driver-owned flags.
 */
static int
if_setflag(struct ifnet *ifp, int flag, int pflag, int *refcount, int onswitch)
{
        struct ifreq ifr;
        int error;
        int oldflags, oldcount;

        /* Sanity checks to catch programming errors */
        KASSERT((flag & (IFF_DRV_OACTIVE|IFF_DRV_RUNNING)) == 0,
            ("%s: setting driver-owned flag %d", __func__, flag));

        if (onswitch)
                KASSERT(*refcount >= 0,
                    ("%s: increment negative refcount %d for flag %d",
                    __func__, *refcount, flag));
        else
                KASSERT(*refcount > 0,
                    ("%s: decrement non-positive refcount %d for flag %d",
                    __func__, *refcount, flag));

        /* In case this mode is permanent, just touch refcount */
        if (ifp->if_flags & pflag) {
                *refcount += onswitch ? 1 : -1;
                return (0);
        }

        /* Save ifnet parameters for if_ioctl() may fail */
        oldcount = *refcount;
        oldflags = ifp->if_flags;

        /*
         * See if we aren't the only and touching refcount is enough.
         * Actually toggle interface flag if we are the first or last.
         */
        if (onswitch) {
                if ((*refcount)++)
                        return (0);
                ifp->if_flags |= flag;
        } else {
                if (--(*refcount))
                        return (0);
                ifp->if_flags &= ~flag;
        }

        /* Call down the driver since we've changed interface flags */
        if (ifp->if_ioctl == NULL) {
                error = EOPNOTSUPP;
                goto recover;
        }
        ifr.ifr_flags = ifp->if_flags & 0xffff;
        ifr.ifr_flagshigh = ifp->if_flags >> 16;
        error = (*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, (caddr_t)&ifr);
        if (error)
                goto recover;
        /* Notify userland that interface flags have changed */
        rt_ifmsg(ifp);
        return (0);

recover:
        /* Recover after driver error */
        *refcount = oldcount;
        ifp->if_flags = oldflags;
        return (error);
}

/*
 * Set/clear promiscuous mode on interface ifp based on the truth value
 * of pswitch.  The calls are reference counted so that only the first
 * "on" request actually has an effect, as does the final "off" request.
 * Results are undefined if the "off" and "on" requests are not matched.
 */
int
ifpromisc(struct ifnet *ifp, int pswitch)
{
        int error;
        int oldflags = ifp->if_flags;

        error = if_setflag(ifp, IFF_PROMISC, IFF_PPROMISC,
                           &ifp->if_pcount, pswitch);
        /* If promiscuous mode status has changed, log a message */
        if (error == 0 && ((ifp->if_flags ^ oldflags) & IFF_PROMISC) &&
            log_promisc_mode_change)
                if_printf(ifp, "promiscuous mode %s\n",
                    (ifp->if_flags & IFF_PROMISC) ? "enabled" : "disabled");
        return (error);
}

/*
 * Return interface configuration
 * of system.  List may be used
 * in later ioctl's (above) to get
 * other information.
 */
/*ARGSUSED*/
static int
ifconf(u_long cmd, caddr_t data)
{
        struct ifconf *ifc = (struct ifconf *)data;
        struct ifnet *ifp;
        struct ifaddr *ifa;
        struct ifreq ifr;
        struct sbuf *sb;
        int error, full = 0, valid_len, max_len;

        /* Limit initial buffer size to maxphys to avoid DoS from userspace. */
        max_len = maxphys - 1;

        /* Prevent hostile input from being able to crash the system */
        if (ifc->ifc_len <= 0)
                return (EINVAL);

again:
        if (ifc->ifc_len <= max_len) {
                max_len = ifc->ifc_len;
                full = 1;
        }
        sb = sbuf_new(NULL, NULL, max_len + 1, SBUF_FIXEDLEN);
        max_len = 0;
        valid_len = 0;

        IFNET_RLOCK();
        CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
                struct epoch_tracker et;
                int addrs;

                /*
                 * Zero the ifr to make sure we don't disclose the contents
                 * of the stack.
                 */
                memset(&ifr, 0, sizeof(ifr));

                if (strlcpy(ifr.ifr_name, ifp->if_xname, sizeof(ifr.ifr_name))
                    >= sizeof(ifr.ifr_name)) {
                        sbuf_delete(sb);
                        IFNET_RUNLOCK();
                        return (ENAMETOOLONG);
                }

                addrs = 0;
                NET_EPOCH_ENTER(et);
                CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                        struct sockaddr *sa = ifa->ifa_addr;

                        if (prison_if(curthread->td_ucred, sa) != 0)
                                continue;
                        addrs++;
                        if (sa->sa_len <= sizeof(*sa)) {
                                if (sa->sa_len < sizeof(*sa)) {
                                        memset(&ifr.ifr_ifru.ifru_addr, 0,
                                            sizeof(ifr.ifr_ifru.ifru_addr));
                                        memcpy(&ifr.ifr_ifru.ifru_addr, sa,
                                            sa->sa_len);
                                } else
                                        ifr.ifr_ifru.ifru_addr = *sa;
                                sbuf_bcat(sb, &ifr, sizeof(ifr));
                                max_len += sizeof(ifr);
                        } else {
                                sbuf_bcat(sb, &ifr,
                                    offsetof(struct ifreq, ifr_addr));
                                max_len += offsetof(struct ifreq, ifr_addr);
                                sbuf_bcat(sb, sa, sa->sa_len);
                                max_len += sa->sa_len;
                        }

                        if (sbuf_error(sb) == 0)
                                valid_len = sbuf_len(sb);
                }
                NET_EPOCH_EXIT(et);
                if (addrs == 0) {
                        sbuf_bcat(sb, &ifr, sizeof(ifr));
                        max_len += sizeof(ifr);

                        if (sbuf_error(sb) == 0)
                                valid_len = sbuf_len(sb);
                }
        }
        IFNET_RUNLOCK();

        /*
         * If we didn't allocate enough space (uncommon), try again.  If
         * we have already allocated as much space as we are allowed,
         * return what we've got.
         */
        if (valid_len != max_len && !full) {
                sbuf_delete(sb);
                goto again;
        }

        ifc->ifc_len = valid_len;
        sbuf_finish(sb);
        error = copyout(sbuf_data(sb), ifc->ifc_req, ifc->ifc_len);
        sbuf_delete(sb);
        return (error);
}

/*
 * Just like ifpromisc(), but for all-multicast-reception mode.
 */
int
if_allmulti(struct ifnet *ifp, int onswitch)
{

        return (if_setflag(ifp, IFF_ALLMULTI, 0, &ifp->if_amcount, onswitch));
}

struct ifmultiaddr *
if_findmulti(struct ifnet *ifp, const struct sockaddr *sa)
{
        struct ifmultiaddr *ifma;

        IF_ADDR_LOCK_ASSERT(ifp);

        CK_STAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
                if (sa->sa_family == AF_LINK) {
                        if (sa_dl_equal(ifma->ifma_addr, sa))
                                break;
                } else {
                        if (sa_equal(ifma->ifma_addr, sa))
                                break;
                }
        }

        return ifma;
}

/*
 * Allocate a new ifmultiaddr and initialize based on passed arguments.  We
 * make copies of passed sockaddrs.  The ifmultiaddr will not be added to
 * the ifnet multicast address list here, so the caller must do that and
 * other setup work (such as notifying the device driver).  The reference
 * count is initialized to 1.
 */
static struct ifmultiaddr *
if_allocmulti(struct ifnet *ifp, struct sockaddr *sa, struct sockaddr *llsa,
    int mflags)
{
        struct ifmultiaddr *ifma;
        struct sockaddr *dupsa;

        ifma = malloc(sizeof *ifma, M_IFMADDR, mflags |
            M_ZERO);
        if (ifma == NULL)
                return (NULL);

        dupsa = malloc(sa->sa_len, M_IFMADDR, mflags);
        if (dupsa == NULL) {
                free(ifma, M_IFMADDR);
                return (NULL);
        }
        bcopy(sa, dupsa, sa->sa_len);
        ifma->ifma_addr = dupsa;

        ifma->ifma_ifp = ifp;
        ifma->ifma_refcount = 1;
        ifma->ifma_protospec = NULL;

        if (llsa == NULL) {
                ifma->ifma_lladdr = NULL;
                return (ifma);
        }

        dupsa = malloc(llsa->sa_len, M_IFMADDR, mflags);
        if (dupsa == NULL) {
                free(ifma->ifma_addr, M_IFMADDR);
                free(ifma, M_IFMADDR);
                return (NULL);
        }
        bcopy(llsa, dupsa, llsa->sa_len);
        ifma->ifma_lladdr = dupsa;

        return (ifma);
}

/*
 * if_freemulti: free ifmultiaddr structure and possibly attached related
 * addresses.  The caller is responsible for implementing reference
 * counting, notifying the driver, handling routing messages, and releasing
 * any dependent link layer state.
 */
#ifdef MCAST_VERBOSE
extern void kdb_backtrace(void);
#endif
static void
if_freemulti_internal(struct ifmultiaddr *ifma)
{

        KASSERT(ifma->ifma_refcount == 0, ("if_freemulti: refcount %d",
            ifma->ifma_refcount));

        if (ifma->ifma_lladdr != NULL)
                free(ifma->ifma_lladdr, M_IFMADDR);
#ifdef MCAST_VERBOSE
        kdb_backtrace();
        printf("%s freeing ifma: %p\n", __func__, ifma);
#endif
        free(ifma->ifma_addr, M_IFMADDR);
        free(ifma, M_IFMADDR);
}

static void
if_destroymulti(epoch_context_t ctx)
{
        struct ifmultiaddr *ifma;

        ifma = __containerof(ctx, struct ifmultiaddr, ifma_epoch_ctx);
        if_freemulti_internal(ifma);
}

void
if_freemulti(struct ifmultiaddr *ifma)
{
        KASSERT(ifma->ifma_refcount == 0, ("if_freemulti_epoch: refcount %d",
            ifma->ifma_refcount));

        NET_EPOCH_CALL(if_destroymulti, &ifma->ifma_epoch_ctx);
}

/*
 * Register an additional multicast address with a network interface.
 *
 * - If the address is already present, bump the reference count on the
 *   address and return.
 * - If the address is not link-layer, look up a link layer address.
 * - Allocate address structures for one or both addresses, and attach to the
 *   multicast address list on the interface.  If automatically adding a link
 *   layer address, the protocol address will own a reference to the link
 *   layer address, to be freed when it is freed.
 * - Notify the network device driver of an addition to the multicast address
 *   list.
 *
 * 'sa' points to caller-owned memory with the desired multicast address.
 *
 * 'retifma' will be used to return a pointer to the resulting multicast
 * address reference, if desired.
 */
int
if_addmulti(struct ifnet *ifp, struct sockaddr *sa,
    struct ifmultiaddr **retifma)
{
        struct ifmultiaddr *ifma, *ll_ifma;
        struct sockaddr *llsa;
        struct sockaddr_dl sdl;
        int error;

#ifdef INET
        IN_MULTI_LIST_UNLOCK_ASSERT();
#endif
#ifdef INET6
        IN6_MULTI_LIST_UNLOCK_ASSERT();
#endif
        /*
         * If the address is already present, return a new reference to it;
         * otherwise, allocate storage and set up a new address.
         */
        IF_ADDR_WLOCK(ifp);
        ifma = if_findmulti(ifp, sa);
        if (ifma != NULL) {
                ifma->ifma_refcount++;
                if (retifma != NULL)
                        *retifma = ifma;
                IF_ADDR_WUNLOCK(ifp);
                return (0);
        }

        /*
         * The address isn't already present; resolve the protocol address
         * into a link layer address, and then look that up, bump its
         * refcount or allocate an ifma for that also.
         * Most link layer resolving functions returns address data which
         * fits inside default sockaddr_dl structure. However callback
         * can allocate another sockaddr structure, in that case we need to
         * free it later.
         */
        llsa = NULL;
        ll_ifma = NULL;
        if (ifp->if_resolvemulti != NULL) {
                /* Provide called function with buffer size information */
                sdl.sdl_len = sizeof(sdl);
                llsa = (struct sockaddr *)&sdl;
                error = ifp->if_resolvemulti(ifp, &llsa, sa);
                if (error)
                        goto unlock_out;
        }

        /*
         * Allocate the new address.  Don't hook it up yet, as we may also
         * need to allocate a link layer multicast address.
         */
        ifma = if_allocmulti(ifp, sa, llsa, M_NOWAIT);
        if (ifma == NULL) {
                error = ENOMEM;
                goto free_llsa_out;
        }

        /*
         * If a link layer address is found, we'll need to see if it's
         * already present in the address list, or allocate is as well.
         * When this block finishes, the link layer address will be on the
         * list.
         */
        if (llsa != NULL) {
                ll_ifma = if_findmulti(ifp, llsa);
                if (ll_ifma == NULL) {
                        ll_ifma = if_allocmulti(ifp, llsa, NULL, M_NOWAIT);
                        if (ll_ifma == NULL) {
                                --ifma->ifma_refcount;
                                if_freemulti(ifma);
                                error = ENOMEM;
                                goto free_llsa_out;
                        }
                        ll_ifma->ifma_flags |= IFMA_F_ENQUEUED;
                        CK_STAILQ_INSERT_HEAD(&ifp->if_multiaddrs, ll_ifma,
                            ifma_link);
                } else
                        ll_ifma->ifma_refcount++;
                ifma->ifma_llifma = ll_ifma;
        }

        /*
         * We now have a new multicast address, ifma, and possibly a new or
         * referenced link layer address.  Add the primary address to the
         * ifnet address list.
         */
        ifma->ifma_flags |= IFMA_F_ENQUEUED;
        CK_STAILQ_INSERT_HEAD(&ifp->if_multiaddrs, ifma, ifma_link);

        if (retifma != NULL)
                *retifma = ifma;

        /*
         * Must generate the message while holding the lock so that 'ifma'
         * pointer is still valid.
         */
        rt_newmaddrmsg(RTM_NEWMADDR, ifma);
        IF_ADDR_WUNLOCK(ifp);

        /*
         * We are certain we have added something, so call down to the
         * interface to let them know about it.
         */
        if (ifp->if_ioctl != NULL) {
                if (THREAD_CAN_SLEEP())
                        (void )(*ifp->if_ioctl)(ifp, SIOCADDMULTI, 0);
                else
                        taskqueue_enqueue(taskqueue_swi, &ifp->if_addmultitask);
        }

        if ((llsa != NULL) && (llsa != (struct sockaddr *)&sdl))
                link_free_sdl(llsa);

        return (0);

free_llsa_out:
        if ((llsa != NULL) && (llsa != (struct sockaddr *)&sdl))
                link_free_sdl(llsa);

unlock_out:
        IF_ADDR_WUNLOCK(ifp);
        return (error);
}

static void
if_siocaddmulti(void *arg, int pending)
{
        struct ifnet *ifp;

        ifp = arg;
#ifdef DIAGNOSTIC
        if (pending > 1)
                if_printf(ifp, "%d SIOCADDMULTI coalesced\n", pending);
#endif
        CURVNET_SET(ifp->if_vnet);
        (void )(*ifp->if_ioctl)(ifp, SIOCADDMULTI, 0);
        CURVNET_RESTORE();
}

/*
 * Delete a multicast group membership by network-layer group address.
 *
 * Returns ENOENT if the entry could not be found. If ifp no longer
 * exists, results are undefined. This entry point should only be used
 * from subsystems which do appropriate locking to hold ifp for the
 * duration of the call.
 * Network-layer protocol domains must use if_delmulti_ifma().
 */
int
if_delmulti(struct ifnet *ifp, struct sockaddr *sa)
{
        struct ifmultiaddr *ifma;
        int lastref;

        KASSERT(ifp, ("%s: NULL ifp", __func__));

        IF_ADDR_WLOCK(ifp);
        lastref = 0;
        ifma = if_findmulti(ifp, sa);
        if (ifma != NULL)
                lastref = if_delmulti_locked(ifp, ifma, 0);
        IF_ADDR_WUNLOCK(ifp);

        if (ifma == NULL)
                return (ENOENT);

        if (lastref && ifp->if_ioctl != NULL) {
                (void)(*ifp->if_ioctl)(ifp, SIOCDELMULTI, 0);
        }

        return (0);
}

/*
 * Delete all multicast group membership for an interface.
 * Should be used to quickly flush all multicast filters.
 */
void
if_delallmulti(struct ifnet *ifp)
{
        struct ifmultiaddr *ifma;
        struct ifmultiaddr *next;

        IF_ADDR_WLOCK(ifp);
        CK_STAILQ_FOREACH_SAFE(ifma, &ifp->if_multiaddrs, ifma_link, next)
                if_delmulti_locked(ifp, ifma, 0);
        IF_ADDR_WUNLOCK(ifp);
}

void
if_delmulti_ifma(struct ifmultiaddr *ifma)
{
        if_delmulti_ifma_flags(ifma, 0);
}

/*
 * Delete a multicast group membership by group membership pointer.
 * Network-layer protocol domains must use this routine.
 *
 * It is safe to call this routine if the ifp disappeared.
 */
void
if_delmulti_ifma_flags(struct ifmultiaddr *ifma, int flags)
{
        struct ifnet *ifp;
        int lastref;
        MCDPRINTF("%s freeing ifma: %p\n", __func__, ifma);
#ifdef INET
        IN_MULTI_LIST_UNLOCK_ASSERT();
#endif
        ifp = ifma->ifma_ifp;
#ifdef DIAGNOSTIC
        if (ifp == NULL) {
                printf("%s: ifma_ifp seems to be detached\n", __func__);
        } else {
                struct epoch_tracker et;
                struct ifnet *oifp;

                NET_EPOCH_ENTER(et);
                CK_STAILQ_FOREACH(oifp, &V_ifnet, if_link)
                        if (ifp == oifp)
                                break;
                NET_EPOCH_EXIT(et);
                if (ifp != oifp)
                        ifp = NULL;
        }
#endif
        /*
         * If and only if the ifnet instance exists: Acquire the address lock.
         */
        if (ifp != NULL)
                IF_ADDR_WLOCK(ifp);

        lastref = if_delmulti_locked(ifp, ifma, flags);

        if (ifp != NULL) {
                /*
                 * If and only if the ifnet instance exists:
                 *  Release the address lock.
                 *  If the group was left: update the hardware hash filter.
                 */
                IF_ADDR_WUNLOCK(ifp);
                if (lastref && ifp->if_ioctl != NULL) {
                        (void)(*ifp->if_ioctl)(ifp, SIOCDELMULTI, 0);
                }
        }
}

/*
 * Perform deletion of network-layer and/or link-layer multicast address.
 *
 * Return 0 if the reference count was decremented.
 * Return 1 if the final reference was released, indicating that the
 * hardware hash filter should be reprogrammed.
 */
static int
if_delmulti_locked(struct ifnet *ifp, struct ifmultiaddr *ifma, int detaching)
{
        struct ifmultiaddr *ll_ifma;

        if (ifp != NULL && ifma->ifma_ifp != NULL) {
                KASSERT(ifma->ifma_ifp == ifp,
                    ("%s: inconsistent ifp %p", __func__, ifp));
                IF_ADDR_WLOCK_ASSERT(ifp);
        }

        ifp = ifma->ifma_ifp;
        MCDPRINTF("%s freeing %p from %s \n", __func__, ifma, ifp ? ifp->if_xname : "");

        /*
         * If the ifnet is detaching, null out references to ifnet,
         * so that upper protocol layers will notice, and not attempt
         * to obtain locks for an ifnet which no longer exists. The
         * routing socket announcement must happen before the ifnet
         * instance is detached from the system.
         */
        if (detaching) {
#ifdef DIAGNOSTIC
                printf("%s: detaching ifnet instance %p\n", __func__, ifp);
#endif
                /*
                 * ifp may already be nulled out if we are being reentered
                 * to delete the ll_ifma.
                 */
                if (ifp != NULL) {
                        rt_newmaddrmsg(RTM_DELMADDR, ifma);
                        ifma->ifma_ifp = NULL;
                }
        }

        if (--ifma->ifma_refcount > 0)
                return 0;

        if (ifp != NULL && detaching == 0 && (ifma->ifma_flags & IFMA_F_ENQUEUED)) {
                CK_STAILQ_REMOVE(&ifp->if_multiaddrs, ifma, ifmultiaddr, ifma_link);
                ifma->ifma_flags &= ~IFMA_F_ENQUEUED;
        }
        /*
         * If this ifma is a network-layer ifma, a link-layer ifma may
         * have been associated with it. Release it first if so.
         */
        ll_ifma = ifma->ifma_llifma;
        if (ll_ifma != NULL) {
                KASSERT(ifma->ifma_lladdr != NULL,
                    ("%s: llifma w/o lladdr", __func__));
                if (detaching)
                        ll_ifma->ifma_ifp = NULL;       /* XXX */
                if (--ll_ifma->ifma_refcount == 0) {
                        if (ifp != NULL) {
                                if (ll_ifma->ifma_flags & IFMA_F_ENQUEUED) {
                                        CK_STAILQ_REMOVE(&ifp->if_multiaddrs, ll_ifma, ifmultiaddr,
                                                ifma_link);
                                        ll_ifma->ifma_flags &= ~IFMA_F_ENQUEUED;
                                }
                        }
                        if_freemulti(ll_ifma);
                }
        }
#ifdef INVARIANTS
        if (ifp) {
                struct ifmultiaddr *ifmatmp;

                CK_STAILQ_FOREACH(ifmatmp, &ifp->if_multiaddrs, ifma_link)
                        MPASS(ifma != ifmatmp);
        }
#endif
        if_freemulti(ifma);
        /*
         * The last reference to this instance of struct ifmultiaddr
         * was released; the hardware should be notified of this change.
         */
        return 1;
}

/*
 * Set the link layer address on an interface.
 *
 * At this time we only support certain types of interfaces,
 * and we don't allow the length of the address to change.
 *
 * Set noinline to be dtrace-friendly
 */
__noinline int
if_setlladdr(struct ifnet *ifp, const u_char *lladdr, int len)
{
        struct sockaddr_dl *sdl;
        struct ifaddr *ifa;
        struct ifreq ifr;

        ifa = ifp->if_addr;
        if (ifa == NULL)
                return (EINVAL);

        sdl = (struct sockaddr_dl *)ifa->ifa_addr;
        if (sdl == NULL)
                return (EINVAL);

        if (len != sdl->sdl_alen)       /* don't allow length to change */
                return (EINVAL);

        switch (ifp->if_type) {
        case IFT_ETHER:
        case IFT_XETHER:
        case IFT_L2VLAN:
        case IFT_BRIDGE:
        case IFT_IEEE8023ADLAG:
                bcopy(lladdr, LLADDR(sdl), len);
                break;
        default:
                return (ENODEV);
        }

        /*
         * If the interface is already up, we need
         * to re-init it in order to reprogram its
         * address filter.
         */
        if ((ifp->if_flags & IFF_UP) != 0) {
                if (ifp->if_ioctl) {
                        ifp->if_flags &= ~IFF_UP;
                        ifr.ifr_flags = ifp->if_flags & 0xffff;
                        ifr.ifr_flagshigh = ifp->if_flags >> 16;
                        (*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, (caddr_t)&ifr);
                        ifp->if_flags |= IFF_UP;
                        ifr.ifr_flags = ifp->if_flags & 0xffff;
                        ifr.ifr_flagshigh = ifp->if_flags >> 16;
                        (*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, (caddr_t)&ifr);
                }
        }
        EVENTHANDLER_INVOKE(iflladdr_event, ifp);

        return (0);
}

/*
 * Compat function for handling basic encapsulation requests.
 * Not converted stacks (FDDI, IB, ..) supports traditional
 * output model: ARP (and other similar L2 protocols) are handled
 * inside output routine, arpresolve/nd6_resolve() returns MAC
 * address instead of full prepend.
 *
 * This function creates calculated header==MAC for IPv4/IPv6 and
 * returns EAFNOSUPPORT (which is then handled in ARP code) for other
 * address families.
 */
static int
if_requestencap_default(struct ifnet *ifp, struct if_encap_req *req)
{

        if (req->rtype != IFENCAP_LL)
                return (EOPNOTSUPP);

        if (req->bufsize < req->lladdr_len)
                return (ENOMEM);

        switch (req->family) {
        case AF_INET:
        case AF_INET6:
                break;
        default:
                return (EAFNOSUPPORT);
        }

        /* Copy lladdr to storage as is */
        memmove(req->buf, req->lladdr, req->lladdr_len);
        req->bufsize = req->lladdr_len;
        req->lladdr_off = 0;

        return (0);
}

/*
 * Tunnel interfaces can nest, also they may cause infinite recursion
 * calls when misconfigured. We'll prevent this by detecting loops.
 * High nesting level may cause stack exhaustion. We'll prevent this
 * by introducing upper limit.
 *
 * Return 0, if tunnel nesting count is equal or less than limit.
 */
int
if_tunnel_check_nesting(struct ifnet *ifp, struct mbuf *m, uint32_t cookie,
    int limit)
{
        struct m_tag *mtag;
        int count;

        count = 1;
        mtag = NULL;
        while ((mtag = m_tag_locate(m, cookie, 0, mtag)) != NULL) {
                if (*(struct ifnet **)(mtag + 1) == ifp) {
                        log(LOG_NOTICE, "%s: loop detected\n", if_name(ifp));
                        return (EIO);
                }
                count++;
        }
        if (count > limit) {
                log(LOG_NOTICE,
                    "%s: if_output recursively called too many times(%d)\n",
                    if_name(ifp), count);
                return (EIO);
        }
        mtag = m_tag_alloc(cookie, 0, sizeof(struct ifnet *), M_NOWAIT);
        if (mtag == NULL)
                return (ENOMEM);
        *(struct ifnet **)(mtag + 1) = ifp;
        m_tag_prepend(m, mtag);
        return (0);
}

/*
 * Get the link layer address that was read from the hardware at attach.
 *
 * This is only set by Ethernet NICs (IFT_ETHER), but laggX interfaces re-type
 * their component interfaces as IFT_IEEE8023ADLAG.
 */
int
if_gethwaddr(struct ifnet *ifp, struct ifreq *ifr)
{

        if (ifp->if_hw_addr == NULL)
                return (ENODEV);

        switch (ifp->if_type) {
        case IFT_ETHER:
        case IFT_IEEE8023ADLAG:
                bcopy(ifp->if_hw_addr, ifr->ifr_addr.sa_data, ifp->if_addrlen);
                return (0);
        default:
                return (ENODEV);
        }
}

/*
 * The name argument must be a pointer to storage which will last as
 * long as the interface does.  For physical devices, the result of
 * device_get_name(dev) is a good choice and for pseudo-devices a
 * static string works well.
 */
void
if_initname(struct ifnet *ifp, const char *name, int unit)
{
        ifp->if_dname = name;
        ifp->if_dunit = unit;
        if (unit != IF_DUNIT_NONE)
                snprintf(ifp->if_xname, IFNAMSIZ, "%s%d", name, unit);
        else
                strlcpy(ifp->if_xname, name, IFNAMSIZ);
}

int
if_printf(struct ifnet *ifp, const char *fmt, ...)
{
        char if_fmt[256];
        va_list ap;

        snprintf(if_fmt, sizeof(if_fmt), "%s: %s", ifp->if_xname, fmt);
        va_start(ap, fmt);
        vlog(LOG_INFO, if_fmt, ap);
        va_end(ap);
        return (0);
}

void
if_start(struct ifnet *ifp)
{

        (*(ifp)->if_start)(ifp);
}

/*
 * Backwards compatibility interface for drivers 
 * that have not implemented it
 */
static int
if_transmit(struct ifnet *ifp, struct mbuf *m)
{
        int error;

        IFQ_HANDOFF(ifp, m, error);
        return (error);
}

static void
if_input_default(struct ifnet *ifp __unused, struct mbuf *m)
{

        m_freem(m);
}

int
if_handoff(struct ifqueue *ifq, struct mbuf *m, struct ifnet *ifp, int adjust)
{
        int active = 0;

        IF_LOCK(ifq);
        if (_IF_QFULL(ifq)) {
                IF_UNLOCK(ifq);
                if_inc_counter(ifp, IFCOUNTER_OQDROPS, 1);
                m_freem(m);
                return (0);
        }
        if (ifp != NULL) {
                if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len + adjust);
                if (m->m_flags & (M_BCAST|M_MCAST))
                        if_inc_counter(ifp, IFCOUNTER_OMCASTS, 1);
                active = ifp->if_drv_flags & IFF_DRV_OACTIVE;
        }
        _IF_ENQUEUE(ifq, m);
        IF_UNLOCK(ifq);
        if (ifp != NULL && !active)
                (*(ifp)->if_start)(ifp);
        return (1);
}

void
if_register_com_alloc(u_char type,
    if_com_alloc_t *a, if_com_free_t *f)
{

        KASSERT(if_com_alloc[type] == NULL,
            ("if_register_com_alloc: %d already registered", type));
        KASSERT(if_com_free[type] == NULL,
            ("if_register_com_alloc: %d free already registered", type));

        if_com_alloc[type] = a;
        if_com_free[type] = f;
}

void
if_deregister_com_alloc(u_char type)
{

        KASSERT(if_com_alloc[type] != NULL,
            ("if_deregister_com_alloc: %d not registered", type));
        KASSERT(if_com_free[type] != NULL,
            ("if_deregister_com_alloc: %d free not registered", type));

        /*
         * Ensure all pending EPOCH(9) callbacks have been executed. This
         * fixes issues about late invocation of if_destroy(), which leads
         * to memory leak from if_com_alloc[type] allocated if_l2com.
         */
        epoch_drain_callbacks(net_epoch_preempt);

        if_com_alloc[type] = NULL;
        if_com_free[type] = NULL;
}

/* API for driver access to network stack owned ifnet.*/
uint64_t
if_setbaudrate(struct ifnet *ifp, uint64_t baudrate)
{
        uint64_t oldbrate;

        oldbrate = ifp->if_baudrate;
        ifp->if_baudrate = baudrate;
        return (oldbrate);
}

uint64_t
if_getbaudrate(if_t ifp)
{

        return (((struct ifnet *)ifp)->if_baudrate);
}

int
if_setcapabilities(if_t ifp, int capabilities)
{
        ((struct ifnet *)ifp)->if_capabilities = capabilities;
        return (0);
}

int
if_setcapabilitiesbit(if_t ifp, int setbit, int clearbit)
{
        ((struct ifnet *)ifp)->if_capabilities |= setbit;
        ((struct ifnet *)ifp)->if_capabilities &= ~clearbit;

        return (0);
}

int
if_getcapabilities(if_t ifp)
{
        return ((struct ifnet *)ifp)->if_capabilities;
}

int 
if_setcapenable(if_t ifp, int capabilities)
{
        ((struct ifnet *)ifp)->if_capenable = capabilities;
        return (0);
}

int 
if_setcapenablebit(if_t ifp, int setcap, int clearcap)
{
        if(setcap) 
                ((struct ifnet *)ifp)->if_capenable |= setcap;
        if(clearcap)
                ((struct ifnet *)ifp)->if_capenable &= ~clearcap;

        return (0);
}

const char *
if_getdname(if_t ifp)
{
        return ((struct ifnet *)ifp)->if_dname;
}

int 
if_togglecapenable(if_t ifp, int togglecap)
{
        ((struct ifnet *)ifp)->if_capenable ^= togglecap;
        return (0);
}

int
if_getcapenable(if_t ifp)
{
        return ((struct ifnet *)ifp)->if_capenable;
}

/*
 * This is largely undesirable because it ties ifnet to a device, but does
 * provide flexiblity for an embedded product vendor. Should be used with
 * the understanding that it violates the interface boundaries, and should be
 * a last resort only.
 */
int
if_setdev(if_t ifp, void *dev)
{
        return (0);
}

int
if_setdrvflagbits(if_t ifp, int set_flags, int clear_flags)
{
        ((struct ifnet *)ifp)->if_drv_flags |= set_flags;
        ((struct ifnet *)ifp)->if_drv_flags &= ~clear_flags;

        return (0);
}

int
if_getdrvflags(if_t ifp)
{
        return ((struct ifnet *)ifp)->if_drv_flags;
}

int
if_setdrvflags(if_t ifp, int flags)
{
        ((struct ifnet *)ifp)->if_drv_flags = flags;
        return (0);
}

int
if_setflags(if_t ifp, int flags)
{

        ifp->if_flags = flags;
        return (0);
}

int
if_setflagbits(if_t ifp, int set, int clear)
{
        ((struct ifnet *)ifp)->if_flags |= set;
        ((struct ifnet *)ifp)->if_flags &= ~clear;

        return (0);
}

int
if_getflags(if_t ifp)
{
        return ((struct ifnet *)ifp)->if_flags;
}

int
if_clearhwassist(if_t ifp)
{
        ((struct ifnet *)ifp)->if_hwassist = 0;
        return (0);
}

int
if_sethwassistbits(if_t ifp, int toset, int toclear)
{
        ((struct ifnet *)ifp)->if_hwassist |= toset;
        ((struct ifnet *)ifp)->if_hwassist &= ~toclear;

        return (0);
}

int
if_sethwassist(if_t ifp, int hwassist_bit)
{
        ((struct ifnet *)ifp)->if_hwassist = hwassist_bit;
        return (0);
}

int
if_gethwassist(if_t ifp)
{
        return ((struct ifnet *)ifp)->if_hwassist;
}

int
if_setmtu(if_t ifp, int mtu)
{
        ((struct ifnet *)ifp)->if_mtu = mtu;
        return (0);
}

int
if_getmtu(if_t ifp)
{
        return ((struct ifnet *)ifp)->if_mtu;
}

int
if_getmtu_family(if_t ifp, int family)
{
        struct domain *dp;

        for (dp = domains; dp; dp = dp->dom_next) {
                if (dp->dom_family == family && dp->dom_ifmtu != NULL)
                        return (dp->dom_ifmtu((struct ifnet *)ifp));
        }

        return (((struct ifnet *)ifp)->if_mtu);
}

/*
 * Methods for drivers to access interface unicast and multicast
 * link level addresses.  Driver shall not know 'struct ifaddr' neither
 * 'struct ifmultiaddr'.
 */
u_int
if_lladdr_count(if_t ifp)
{
        struct epoch_tracker et;
        struct ifaddr *ifa;
        u_int count;

        count = 0;
        NET_EPOCH_ENTER(et);
        CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
                if (ifa->ifa_addr->sa_family == AF_LINK)
                        count++;
        NET_EPOCH_EXIT(et);

        return (count);
}

u_int
if_foreach_lladdr(if_t ifp, iflladdr_cb_t cb, void *cb_arg)
{
        struct epoch_tracker et;
        struct ifaddr *ifa;
        u_int count;

        MPASS(cb);

        count = 0;
        NET_EPOCH_ENTER(et);
        CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                if (ifa->ifa_addr->sa_family != AF_LINK)
                        continue;
                count += (*cb)(cb_arg, (struct sockaddr_dl *)ifa->ifa_addr,
                    count);
        }
        NET_EPOCH_EXIT(et);

        return (count);
}

u_int
if_llmaddr_count(if_t ifp)
{
        struct epoch_tracker et;
        struct ifmultiaddr *ifma;
        int count;

        count = 0;
        NET_EPOCH_ENTER(et);
        CK_STAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link)
                if (ifma->ifma_addr->sa_family == AF_LINK)
                        count++;
        NET_EPOCH_EXIT(et);

        return (count);
}

u_int
if_foreach_llmaddr(if_t ifp, iflladdr_cb_t cb, void *cb_arg)
{
        struct epoch_tracker et;
        struct ifmultiaddr *ifma;
        u_int count;

        MPASS(cb);

        count = 0;
        NET_EPOCH_ENTER(et);
        CK_STAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
                if (ifma->ifma_addr->sa_family != AF_LINK)
                        continue;
                count += (*cb)(cb_arg, (struct sockaddr_dl *)ifma->ifma_addr,
                    count);
        }
        NET_EPOCH_EXIT(et);

        return (count);
}

int
if_setsoftc(if_t ifp, void *softc)
{
        ((struct ifnet *)ifp)->if_softc = softc;
        return (0);
}

void *
if_getsoftc(if_t ifp)
{
        return ((struct ifnet *)ifp)->if_softc;
}

void 
if_setrcvif(struct mbuf *m, if_t ifp)
{

        MPASS((m->m_pkthdr.csum_flags & CSUM_SND_TAG) == 0);
        m->m_pkthdr.rcvif = (struct ifnet *)ifp;
}

void 
if_setvtag(struct mbuf *m, uint16_t tag)
{
        m->m_pkthdr.ether_vtag = tag;   
}

uint16_t
if_getvtag(struct mbuf *m)
{

        return (m->m_pkthdr.ether_vtag);
}

int
if_sendq_empty(if_t ifp)
{
        return IFQ_DRV_IS_EMPTY(&((struct ifnet *)ifp)->if_snd);
}

struct ifaddr *
if_getifaddr(if_t ifp)
{
        return ((struct ifnet *)ifp)->if_addr;
}

int
if_getamcount(if_t ifp)
{
        return ((struct ifnet *)ifp)->if_amcount;
}

int
if_setsendqready(if_t ifp)
{
        IFQ_SET_READY(&((struct ifnet *)ifp)->if_snd);
        return (0);
}

int
if_setsendqlen(if_t ifp, int tx_desc_count)
{
        IFQ_SET_MAXLEN(&((struct ifnet *)ifp)->if_snd, tx_desc_count);
        ((struct ifnet *)ifp)->if_snd.ifq_drv_maxlen = tx_desc_count;

        return (0);
}

int
if_vlantrunkinuse(if_t ifp)
{
        return ((struct ifnet *)ifp)->if_vlantrunk != NULL?1:0;
}

int
if_input(if_t ifp, struct mbuf* sendmp)
{
        (*((struct ifnet *)ifp)->if_input)((struct ifnet *)ifp, sendmp);
        return (0);

}

struct mbuf *
if_dequeue(if_t ifp)
{
        struct mbuf *m;
        IFQ_DRV_DEQUEUE(&((struct ifnet *)ifp)->if_snd, m);

        return (m);
}

int
if_sendq_prepend(if_t ifp, struct mbuf *m)
{
        IFQ_DRV_PREPEND(&((struct ifnet *)ifp)->if_snd, m);
        return (0);
}

int
if_setifheaderlen(if_t ifp, int len)
{
        ((struct ifnet *)ifp)->if_hdrlen = len;
        return (0);
}

caddr_t
if_getlladdr(if_t ifp)
{
        return (IF_LLADDR((struct ifnet *)ifp));
}

void *
if_gethandle(u_char type)
{
        return (if_alloc(type));
}

void
if_bpfmtap(if_t ifh, struct mbuf *m)
{
        struct ifnet *ifp = (struct ifnet *)ifh;

        BPF_MTAP(ifp, m);
}

void
if_etherbpfmtap(if_t ifh, struct mbuf *m)
{
        struct ifnet *ifp = (struct ifnet *)ifh;

        ETHER_BPF_MTAP(ifp, m);
}

void
if_vlancap(if_t ifh)
{
        struct ifnet *ifp = (struct ifnet *)ifh;
        VLAN_CAPABILITIES(ifp);
}

int
if_sethwtsomax(if_t ifp, u_int if_hw_tsomax)
{

        ((struct ifnet *)ifp)->if_hw_tsomax = if_hw_tsomax;
        return (0);
}

int
if_sethwtsomaxsegcount(if_t ifp, u_int if_hw_tsomaxsegcount)
{

        ((struct ifnet *)ifp)->if_hw_tsomaxsegcount = if_hw_tsomaxsegcount;
        return (0);
}

int
if_sethwtsomaxsegsize(if_t ifp, u_int if_hw_tsomaxsegsize)
{

        ((struct ifnet *)ifp)->if_hw_tsomaxsegsize = if_hw_tsomaxsegsize;
        return (0);
}

u_int
if_gethwtsomax(if_t ifp)
{

        return (((struct ifnet *)ifp)->if_hw_tsomax);
}

u_int
if_gethwtsomaxsegcount(if_t ifp)
{

        return (((struct ifnet *)ifp)->if_hw_tsomaxsegcount);
}

u_int
if_gethwtsomaxsegsize(if_t ifp)
{

        return (((struct ifnet *)ifp)->if_hw_tsomaxsegsize);
}

void
if_setinitfn(if_t ifp, void (*init_fn)(void *))
{
        ((struct ifnet *)ifp)->if_init = init_fn;
}

void
if_setioctlfn(if_t ifp, int (*ioctl_fn)(if_t, u_long, caddr_t))
{
        ((struct ifnet *)ifp)->if_ioctl = (void *)ioctl_fn;
}

void
if_setstartfn(if_t ifp, void (*start_fn)(if_t))
{
        ((struct ifnet *)ifp)->if_start = (void *)start_fn;
}

void
if_settransmitfn(if_t ifp, if_transmit_fn_t start_fn)
{
        ((struct ifnet *)ifp)->if_transmit = start_fn;
}

void if_setqflushfn(if_t ifp, if_qflush_fn_t flush_fn)
{
        ((struct ifnet *)ifp)->if_qflush = flush_fn;

}

void
if_setgetcounterfn(if_t ifp, if_get_counter_t fn)
{

        ifp->if_get_counter = fn;
}

/* Revisit these - These are inline functions originally. */
int
drbr_inuse_drv(if_t ifh, struct buf_ring *br)
{
        return drbr_inuse(ifh, br);
}

struct mbuf*
drbr_dequeue_drv(if_t ifh, struct buf_ring *br)
{
        return drbr_dequeue(ifh, br);
}

int
drbr_needs_enqueue_drv(if_t ifh, struct buf_ring *br)
{
        return drbr_needs_enqueue(ifh, br);
}

int
drbr_enqueue_drv(if_t ifh, struct buf_ring *br, struct mbuf *m)
{
        return drbr_enqueue(ifh, br, m);

}