source: rtems-libbsd/freebsd/sys/net/if.c @ 2404264

#include <machine/rtems-bsd-config.h>

/*-
 * 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.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)if.c        8.5 (Berkeley) 1/9/95
 * $FreeBSD$
 */

#include <rtems/bsd/local/opt_compat.h>
#include <rtems/bsd/local/opt_inet6.h>
#include <rtems/bsd/local/opt_inet.h>

#include <rtems/bsd/sys/param.h>
#include <rtems/bsd/sys/types.h>
#include <sys/conf.h>
#include <sys/malloc.h>
#include <sys/sbuf.h>
#include <sys/bus.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 <rtems/bsd/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/taskqueue.h>
#include <sys/domain.h>
#include <sys/jail.h>
#include <machine/stdarg.h>
#include <vm/uma.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/radix.h>
#include <net/route.h>
#include <net/vnet.h>

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

#include <security/mac/mac_framework.h>

#ifdef COMPAT_FREEBSD32
#include <sys/mount.h>
#include <compat/freebsd32/freebsd32.h>
#endif

struct ifindex_entry {
        struct  ifnet *ife_ifnet;
};

static int slowtimo_started;

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

TUNABLE_INT("net.link.ifqmaxlen", &ifqmaxlen);
SYSCTL_UINT(_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");

/* 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");

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    (*bstp_linkstate_p)(struct ifnet *ifp, int state);
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);
#if defined(INET) || defined(INET6)
struct ifnet *(*carp_forus_p)(struct ifnet *ifp, u_char *dhost);
int     (*carp_output_p)(struct ifnet *ifp, struct mbuf *m,
    struct sockaddr *sa, struct rtentry *rt);
#endif
#ifdef INET
int (*carp_iamatch_p)(struct ifnet *, struct in_ifaddr *, struct in_addr *,
    u_int8_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_freemulti(struct ifmultiaddr *);
static void     if_init(void *);
static void     if_grow(void);
static void     if_check(void *);
static void     if_route(struct ifnet *, int flag, int fam);
static int      if_setflag(struct ifnet *, int, int, int *, int);
static void     if_slowtimo(void *);
static int      if_transmit(struct ifnet *ifp, struct mbuf *m);
static void     if_unroute(struct ifnet *, int flag, int fam);
static void     link_rtrequest(int, struct rtentry *, struct rt_addrinfo *);
static int      if_rtdel(struct radix_node *, void *);
static int      ifhwioctl(u_long, struct ifnet *, caddr_t, struct thread *);
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);
static void     if_detach_internal(struct ifnet *, int);

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

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);

static VNET_DEFINE(int, if_indexlim) = 8;

/* Table of ifnet by index. */
VNET_DEFINE(struct ifindex_entry *, 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 and
 * an rwlock.  Either may be acquired shared to stablize the list, but both
 * must be acquired writable to modify the list.  This model allows us to
 * both stablize the interface list during interrupt thread processing, but
 * also to stablize it over long-running ioctls, without introducing priority
 * inversions and deadlocks.
 */
struct rwlock ifnet_rwlock;
struct sx ifnet_sxlock;

/*
 * 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)

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

/*
 * System initialization
 */
SYSINIT(interface_check, SI_SUB_PROTO_IF, SI_ORDER_FIRST, if_check, NULL);

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_locked(u_short idx)
{

        if (idx > V_if_index)
                return (NULL);
        if (V_ifindex_table[idx].ife_ifnet == IFNET_HOLD)
                return (NULL);
        return (V_ifindex_table[idx].ife_ifnet);
}

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

        IFNET_RLOCK_NOSLEEP();
        ifp = ifnet_byindex_locked(idx);
        IFNET_RUNLOCK_NOSLEEP();
        return (ifp);
}

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

        IFNET_RLOCK_NOSLEEP();
        ifp = ifnet_byindex_locked(idx);
        if (ifp == NULL || (ifp->if_flags & IFF_DYING)) {
                IFNET_RUNLOCK_NOSLEEP();
                return (NULL);
        }
        if_ref(ifp);
        IFNET_RUNLOCK_NOSLEEP();
        return (ifp);
}

/*
 * Allocate an ifindex array entry; return 0 on success or an error on
 * failure.
 */
static int
ifindex_alloc_locked(u_short *idxp)
{
        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].ife_ifnet == NULL)
                        break;
        }

        /* Catch if_index overflow. */
        if (idx < 1)
                return (ENOSPC);
        if (idx > V_if_index)
                V_if_index = idx;
        if (V_if_index >= V_if_indexlim)
                if_grow();
        *idxp = idx;
        return (0);
}

static void
ifindex_free_locked(u_short idx)
{

        IFNET_WLOCK_ASSERT();

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

static void
ifindex_free(u_short idx)
{

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

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

        IFNET_WLOCK_ASSERT();

        V_ifindex_table[idx].ife_ifnet = ifp;
}

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

        IFNET_WLOCK();
        ifnet_setbyindex_locked(idx, ifp);
        IFNET_WUNLOCK();
}

struct ifaddr *
ifaddr_byindex(u_short idx)
{
        struct ifaddr *ifa;

        IFNET_RLOCK_NOSLEEP();
        ifa = ifnet_byindex_locked(idx)->if_addr;
        if (ifa != NULL)
                ifa_ref(ifa);
        IFNET_RUNLOCK_NOSLEEP();
        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)
{

        TAILQ_INIT(&V_ifnet);
        TAILQ_INIT(&V_ifg_head);
        if_grow();                              /* create initial table */
        vnet_if_clone_init();
}
VNET_SYSINIT(vnet_if_init, SI_SUB_INIT_IF, SI_ORDER_FIRST, vnet_if_init,
    NULL);

/* ARGSUSED*/
static void
if_init(void *dummy __unused)
{

        IFNET_LOCK_INIT();
        if_clone_init();
}
SYSINIT(interfaces, SI_SUB_INIT_IF, SI_ORDER_SECOND, if_init, NULL);


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

        VNET_ASSERT(TAILQ_EMPTY(&V_ifnet));
        VNET_ASSERT(TAILQ_EMPTY(&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_grow(void)
{
        u_int n;
        struct ifindex_entry *e;

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

static void
if_check(void *dummy __unused)
{

        /*
         * If at least one interface added during boot uses
         * if_watchdog then start the timer.
         */
        if (slowtimo_started)
                if_slowtimo(0);
}

/*
 * 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(u_char type)
{
        struct ifnet *ifp;
        u_short idx;

        ifp = malloc(sizeof(struct ifnet), M_IFNET, M_WAITOK|M_ZERO);
        IFNET_WLOCK();
        if (ifindex_alloc_locked(&idx) != 0) {
                IFNET_WUNLOCK();
                free(ifp, M_IFNET);
                return (NULL);
        }
        ifnet_setbyindex_locked(idx, IFNET_HOLD);
        IFNET_WUNLOCK();
        ifp->if_index = idx;
        ifp->if_type = type;
        ifp->if_alloctype = type;
        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);
        ifp->if_afdata_initialized = 0;
        IF_AFDATA_LOCK_INIT(ifp);
        TAILQ_INIT(&ifp->if_addrhead);
        TAILQ_INIT(&ifp->if_prefixhead);
        TAILQ_INIT(&ifp->if_multiaddrs);
        TAILQ_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. */
        ifnet_setbyindex(ifp->if_index, ifp);
        return (ifp);
}

/*
 * Do the actual work of freeing a struct ifnet, associated index, 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"));

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

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

        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 (ifp->if_description != NULL)
                free(ifp->if_description, M_IFDESCR);
        IF_AFDATA_DESTROY(ifp);
        IF_ADDR_LOCK_DESTROY(ifp);
        ifq_delete(&ifp->if_snd);
        free(ifp, M_IFNET);
}

/*
 * This version should only be called by intefaces that switch their type
 * after calling if_alloc().  if_free_type() will go away again now that we
 * have if_alloctype to cache the original allocation type.  For now, assert
 * that they match, since we require that in practice.
 */
void
if_free_type(struct ifnet *ifp, u_char type)
{

        KASSERT(ifp->if_alloctype == type,
            ("if_free_type: type (%d) != alloctype (%d)", type,
            ifp->if_alloctype));

        ifp->if_flags |= IFF_DYING;                     /* XXX: Locking */
        if (!refcount_release(&ifp->if_refcount))
                return;
        if_free_internal(ifp);
}

/*
 * This is the normal version of if_free(), used by device drivers to free a
 * detached network interface.  The contents of if_free_type() will move into
 * here when if_free_type() goes away.
 */
void
if_free(struct ifnet *ifp)
{

        if_free_type(ifp, ifp->if_alloctype);
}

/*
 * 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)
{

        /* We don't assert the ifnet list lock here, but arguably should. */
        refcount_acquire(&ifp->if_refcount);
}

void
if_rele(struct ifnet *ifp)
{

        if (!refcount_release(&ifp->if_refcount))
                return;
        if_free_internal(ifp);
}

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 initalization 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.
 *
 * 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);
}

static void
if_attach_internal(struct ifnet *ifp, int vmove)
{
        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);

        getmicrotime(&ifp->if_lastchange);
        ifp->if_data.ifi_epoch = time_uptime;
        ifp->if_data.ifi_datalen = sizeof(struct if_data);

        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 (!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 = malloc(ifasize, M_IFADDR, M_WAITOK | M_ZERO);
                ifa_init(ifa);
                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_rtrequest = link_rtrequest;
                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;
                TAILQ_INSERT_HEAD(&ifp->if_addrhead, ifa, ifa_link);
                /* Reliably crash if used uninitialized. */
                ifp->if_broadcastaddr = NULL;
        }
#ifdef VIMAGE
        else {
                /*
                 * Update the interface index in the link layer address
                 * of the interface.
                 */
                for (ifa = ifp->if_addr; ifa != NULL;
                    ifa = TAILQ_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

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

        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);

        if (!vmove && ifp->if_watchdog != NULL) {
                if_printf(ifp,
                    "WARNING: using obsoleted if_watchdog interface\n");

                /*
                 * Note that we need if_slowtimo().  If this happens after
                 * boot, then call if_slowtimo() directly.
                 */
                if (atomic_cmpset_int(&slowtimo_started, 0, 1) && !cold)
                        if_slowtimo(0);
        }
}

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

        s = splnet();
        TAILQ_FOREACH(ifp, &V_ifnet, if_link)
                if_attachdomain1(ifp);
        splx(s);
}
SYSINIT(domainifattach, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_SECOND,
    if_attachdomain, NULL);

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

        s = splnet();

        /*
         * Since dp->dom_ifattach calls malloc() with M_WAITOK, we
         * cannot lock ifp->if_afdata initialization, entirely.
         */
        if (IF_AFDATA_TRYLOCK(ifp) == 0) {
                splx(s);
                return;
        }
        if (ifp->if_afdata_initialized >= domain_init_status) {
                IF_AFDATA_UNLOCK(ifp);
                splx(s);
                printf("if_attachdomain called more than once on %s\n",
                    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);
        }

        splx(s);
}

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

        TAILQ_FOREACH_SAFE(ifa, &ifp->if_addrhead, ifa_link, next) {
                if (ifa->ifa_addr->sa_family == AF_LINK)
                        continue;
#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_purgeaddr(ifa);
                        /* ifp_addrhead is already updated */
                        continue;
                }
#endif /* INET6 */
                TAILQ_REMOVE(&ifp->if_addrhead, ifa, ifa_link);
                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;
        struct ifmultiaddr *next;

        IF_ADDR_LOCK(ifp);
        TAILQ_FOREACH_SAFE(ifma, &ifp->if_multiaddrs, ifma_link, next)
                if_delmulti_locked(ifp, ifma, 1);
        IF_ADDR_UNLOCK(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)
{

        if_detach_internal(ifp, 0);
}

static void
if_detach_internal(struct ifnet *ifp, int vmove)
{
        struct ifaddr *ifa;
        struct radix_node_head  *rnh;
        int i, j;
        struct domain *dp;
        struct ifnet *iter;
        int found = 0;

        IFNET_WLOCK();
        TAILQ_FOREACH(iter, &V_ifnet, if_link)
                if (iter == ifp) {
                        TAILQ_REMOVE(&V_ifnet, ifp, if_link);
                        found = 1;
                        break;
                }
#ifdef VIMAGE
        if (found)
                curvnet->vnet_ifcnt--;
#endif
        IFNET_WUNLOCK();
        if (!found) {
                if (vmove)
                        panic("%s: ifp=%p not on the ifnet tailq %p",
                            __func__, ifp, &V_ifnet);
                else
                        return; /* XXX this should panic as well? */
        }

        /*
         * Remove/wait for pending events.
         */
        taskqueue_drain(taskqueue_swi, &ifp->if_linktask);

        /*
         * Remove routes and flush queues.
         */
        if_down(ifp);
#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);

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

                /*
                 * Remove link ifaddr pointer and maybe decrement if_index.
                 * Clean up all addresses.
                 */
                ifp->if_addr = NULL;

                /* We can now free link ifaddr. */
                if (!TAILQ_EMPTY(&ifp->if_addrhead)) {
                        ifa = TAILQ_FIRST(&ifp->if_addrhead);
                        TAILQ_REMOVE(&ifp->if_addrhead, ifa, ifa_link);
                        ifa_free(ifa);
                }
        }

        /*
         * Delete all remaining routes using this interface
         * Unfortuneatly the only way to do this is to slog through
         * the entire routing table looking for routes which point
         * to this interface...oh well...
         */
        for (i = 1; i <= AF_MAX; i++) {
                for (j = 0; j < rt_numfibs; j++) {
                        rnh = rt_tables_get_rnh(j, i);
                        if (rnh == NULL)
                                continue;
                        RADIX_NODE_HEAD_LOCK(rnh);
                        (void) rnh->rnh_walktree(rnh, if_rtdel, ifp);
                        RADIX_NODE_HEAD_UNLOCK(rnh);
                }
        }

        /* 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_delgroups(ifp);

        /*
         * 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]);
        }
}

#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.
 */
void
if_vmove(struct ifnet *ifp, struct vnet *new_vnet)
{
        u_short idx;

        /*
         * Detach from current vnet, but preserve LLADDR info, do not
         * mark as dead etc. so that the ifnet can be reattached later.
         */
        if_detach_internal(ifp, 1);

        /*
         * 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);

        IFNET_WLOCK();
        if (ifindex_alloc_locked(&idx) != 0) {
                IFNET_WUNLOCK();
                panic("if_index overflow");
        }
        ifp->if_index = idx;
        ifnet_setbyindex_locked(ifp->if_index, ifp);
        IFNET_WUNLOCK();

        if_attach_internal(ifp, 1);

        CURVNET_RESTORE();
}

/*
 * 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;

        /* 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);
        CURVNET_RESTORE();
        if (difp != NULL) {
                prison_free(pr);
                return (EEXIST);
        }

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

        /* Report the new if_xname back to the userland. */
        sprintf(ifname, "%s", ifp->if_xname);

        prison_free(pr);
        return (0);
}

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

        /* 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);
        }

        /* Get interface back from child jail/vnet. */
        if_vmove(ifp, vnet_dst);
        CURVNET_RESTORE();

        /* Report the new if_xname back to the userland. */
        sprintf(ifname, "%s", ifp->if_xname);

        prison_free(pr);
        return (0);
}
#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;

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

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

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

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

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

        if (ifg == NULL) {
                if ((ifg = (struct ifg_group *)malloc(sizeof(struct ifg_group),
                    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;
                TAILQ_INIT(&ifg->ifg_members);
                EVENTHANDLER_INVOKE(group_attach_event, ifg);
                TAILQ_INSERT_TAIL(&V_ifg_head, ifg, ifg_next);
        }

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

        IF_ADDR_LOCK(ifp);
        TAILQ_INSERT_TAIL(&ifg->ifg_members, ifgm, ifgm_next);
        TAILQ_INSERT_TAIL(&ifp->if_groups, ifgl, ifgl_next);
        IF_ADDR_UNLOCK(ifp);

        IFNET_WUNLOCK();

        EVENTHANDLER_INVOKE(group_change_event, groupname);

        return (0);
}

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

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

        IF_ADDR_LOCK(ifp);
        TAILQ_REMOVE(&ifp->if_groups, ifgl, ifgl_next);
        IF_ADDR_UNLOCK(ifp);

        TAILQ_FOREACH(ifgm, &ifgl->ifgl_group->ifg_members, ifgm_next)
                if (ifgm->ifgm_ifp == ifp)
                        break;

        if (ifgm != NULL) {
                TAILQ_REMOVE(&ifgl->ifgl_group->ifg_members, ifgm, ifgm_next);
                free(ifgm, M_TEMP);
        }

        if (--ifgl->ifgl_group->ifg_refcnt == 0) {
                TAILQ_REMOVE(&V_ifg_head, ifgl->ifgl_group, ifg_next);
                EVENTHANDLER_INVOKE(group_detach_event, ifgl->ifgl_group);
                free(ifgl->ifgl_group, M_TEMP);
        }
        IFNET_WUNLOCK();

        free(ifgl, M_TEMP);

        EVENTHANDLER_INVOKE(group_change_event, groupname);

        return (0);
}

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

        IFNET_WLOCK();
        while (!TAILQ_EMPTY(&ifp->if_groups)) {
                ifgl = TAILQ_FIRST(&ifp->if_groups);

                strlcpy(groupname, ifgl->ifgl_group->ifg_group, IFNAMSIZ);

                IF_ADDR_LOCK(ifp);
                TAILQ_REMOVE(&ifp->if_groups, ifgl, ifgl_next);
                IF_ADDR_UNLOCK(ifp);

                TAILQ_FOREACH(ifgm, &ifgl->ifgl_group->ifg_members, ifgm_next)
                        if (ifgm->ifgm_ifp == ifp)
                                break;

                if (ifgm != NULL) {
                        TAILQ_REMOVE(&ifgl->ifgl_group->ifg_members, ifgm,
                            ifgm_next);
                        free(ifgm, M_TEMP);
                }

                if (--ifgl->ifgl_group->ifg_refcnt == 0) {
                        TAILQ_REMOVE(&V_ifg_head, ifgl->ifgl_group, ifg_next);
                        EVENTHANDLER_INVOKE(group_detach_event,
                            ifgl->ifgl_group);
                        free(ifgl->ifgl_group, M_TEMP);
                }
                IFNET_WUNLOCK();

                free(ifgl, M_TEMP);

                EVENTHANDLER_INVOKE(group_change_event, groupname);

                IFNET_WLOCK();
        }
        IFNET_WUNLOCK();
}

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

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

        len = ifgr->ifgr_len;
        ifgp = ifgr->ifgr_groups;
        /* XXX: wire */
        IF_ADDR_LOCK(ifp);
        TAILQ_FOREACH(ifgl, &ifp->if_groups, ifgl_next) {
                if (len < sizeof(ifgrq)) {
                        IF_ADDR_UNLOCK(ifp);
                        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)))) {
                        IF_ADDR_UNLOCK(ifp);
                        return (error);
                }
                len -= sizeof(ifgrq);
                ifgp++;
        }
        IF_ADDR_UNLOCK(ifp);

        return (0);
}

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

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

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

        len = ifgr->ifgr_len;
        ifgp = ifgr->ifgr_groups;
        TAILQ_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);
}

/*
 * Delete Routes for a Network Interface
 *
 * Called for each routing entry via the rnh->rnh_walktree() call above
 * to delete all route entries referencing a detaching network interface.
 *
 * Arguments:
 *      rn      pointer to node in the routing table
 *      arg     argument passed to rnh->rnh_walktree() - detaching interface
 *
 * Returns:
 *      0       successful
 *      errno   failed - reason indicated
 *
 */
static int
if_rtdel(struct radix_node *rn, void *arg)
{
        struct rtentry  *rt = (struct rtentry *)rn;
        struct ifnet    *ifp = arg;
        int             err;

        if (rt->rt_ifp == ifp) {

                /*
                 * Protect (sorta) against walktree recursion problems
                 * with cloned routes
                 */
                if ((rt->rt_flags & RTF_UP) == 0)
                        return (0);

                err = rtrequest_fib(RTM_DELETE, rt_key(rt), rt->rt_gateway,
                                rt_mask(rt), rt->rt_flags|RTF_RNH_LOCKED,
                                (struct rtentry **) NULL, rt->rt_fibnum);
                if (err) {
                        log(LOG_WARNING, "if_rtdel: error %d\n", err);
                }
        }

        return (0);
}

/*
 * Wrapper functions for struct ifnet address list locking macros.  These are
 * used by kernel modules to avoid encoding programming interface or binary
 * interface assumptions that may be violated when kernel-internal locking
 * approaches change.
 */
void
if_addr_rlock(struct ifnet *ifp)
{

        IF_ADDR_LOCK(ifp);
}

void
if_addr_runlock(struct ifnet *ifp)
{

        IF_ADDR_UNLOCK(ifp);
}

void
if_maddr_rlock(struct ifnet *ifp)
{

        IF_ADDR_LOCK(ifp);
}

void
if_maddr_runlock(struct ifnet *ifp)
{

        IF_ADDR_UNLOCK(ifp);
}

/*
 * Reference count functions for ifaddrs.
 */
void
ifa_init(struct ifaddr *ifa)
{

        mtx_init(&ifa->ifa_mtx, "ifaddr", NULL, MTX_DEF);
        refcount_init(&ifa->ifa_refcnt, 1);
}

void
ifa_ref(struct ifaddr *ifa)
{

        refcount_acquire(&ifa->ifa_refcnt);
}

void
ifa_free(struct ifaddr *ifa)
{

        if (refcount_release(&ifa->ifa_refcnt)) {
                mtx_destroy(&ifa->ifa_mtx);
                free(ifa, M_IFADDR);
        }
}

int
ifa_add_loopback_route(struct ifaddr *ifa, struct sockaddr *ia)
{
        int error = 0;
        struct rtentry *rt = NULL;
        struct rt_addrinfo info;
        static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK};

        bzero(&info, sizeof(info));
        info.rti_ifp = V_loif;
        info.rti_flags = ifa->ifa_flags | RTF_HOST | RTF_STATIC;
        info.rti_info[RTAX_DST] = ia;
        info.rti_info[RTAX_GATEWAY] = (struct sockaddr *)&null_sdl;
        error = rtrequest1_fib(RTM_ADD, &info, &rt, 0);

        if (error == 0 && rt != NULL) {
                RT_LOCK(rt);
                ((struct sockaddr_dl *)rt->rt_gateway)->sdl_type  =
                        ifa->ifa_ifp->if_type;
                ((struct sockaddr_dl *)rt->rt_gateway)->sdl_index =
                        ifa->ifa_ifp->if_index;
                RT_REMREF(rt);
                RT_UNLOCK(rt);
        } else if (error != 0)
                log(LOG_INFO, "ifa_add_loopback_route: insertion failed\n");

        return (error);
}

int
ifa_del_loopback_route(struct ifaddr *ifa, struct sockaddr *ia)
{
        int error = 0;
        struct rt_addrinfo info;
        struct sockaddr_dl null_sdl;

        bzero(&null_sdl, sizeof(null_sdl));
        null_sdl.sdl_len = sizeof(null_sdl);
        null_sdl.sdl_family = AF_LINK;
        null_sdl.sdl_type = ifa->ifa_ifp->if_type;
        null_sdl.sdl_index = ifa->ifa_ifp->if_index;
        bzero(&info, sizeof(info));
        info.rti_flags = ifa->ifa_flags | RTF_HOST | RTF_STATIC;
        info.rti_info[RTAX_DST] = ia;
        info.rti_info[RTAX_GATEWAY] = (struct sockaddr *)&null_sdl;
        error = rtrequest1_fib(RTM_DELETE, &info, NULL, 0);

        if (error != 0)
                log(LOG_INFO, "ifa_del_loopback_route: deletion failed\n");

        return (error);
}

/*
 * 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_equal(a1, a2)        \
        (bcmp((a1), (a2), ((a1))->sa_len) == 0)

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

/*
 * Locate an interface based on a complete address.
 */
/*ARGSUSED*/
static struct ifaddr *
ifa_ifwithaddr_internal(struct sockaddr *addr, int getref)
{
        struct ifnet *ifp;
        struct ifaddr *ifa;

        IFNET_RLOCK_NOSLEEP();
        TAILQ_FOREACH(ifp, &V_ifnet, if_link) {
                IF_ADDR_LOCK(ifp);
                TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                        if (ifa->ifa_addr->sa_family != addr->sa_family)
                                continue;
                        if (sa_equal(addr, ifa->ifa_addr)) {
                                if (getref)
                                        ifa_ref(ifa);
                                IF_ADDR_UNLOCK(ifp);
                                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)) {
                                if (getref)
                                        ifa_ref(ifa);
                                IF_ADDR_UNLOCK(ifp);
                                goto done;
                        }
                }
                IF_ADDR_UNLOCK(ifp);
        }
        ifa = NULL;
done:
        IFNET_RUNLOCK_NOSLEEP();
        return (ifa);
}

struct ifaddr *
ifa_ifwithaddr(struct sockaddr *addr)
{

        return (ifa_ifwithaddr_internal(addr, 1));
}

int
ifa_ifwithaddr_check(struct sockaddr *addr)
{

        return (ifa_ifwithaddr_internal(addr, 0) != NULL);
}

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

        IFNET_RLOCK_NOSLEEP();
        TAILQ_FOREACH(ifp, &V_ifnet, if_link) {
                IF_ADDR_LOCK(ifp);
                TAILQ_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)) {
                                ifa_ref(ifa);
                                IF_ADDR_UNLOCK(ifp);
                                goto done;
                        }
                }
                IF_ADDR_UNLOCK(ifp);
        }
        ifa = NULL;
done:
        IFNET_RUNLOCK_NOSLEEP();
        return (ifa);
}

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

        IFNET_RLOCK_NOSLEEP();
        TAILQ_FOREACH(ifp, &V_ifnet, if_link) {
                if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
                        continue;
                IF_ADDR_LOCK(ifp);
                TAILQ_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)) {
                                ifa_ref(ifa);
                                IF_ADDR_UNLOCK(ifp);
                                goto done;
                        }
                }
                IF_ADDR_UNLOCK(ifp);
        }
        ifa = NULL;
done:
        IFNET_RUNLOCK_NOSLEEP();
        return (ifa);
}

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

        /*
         * AF_LINK addresses can be looked up directly by their index number,
         * so do that if we can.
         */
        if (af == AF_LINK) {
            struct sockaddr_dl *sdl = (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.  Maintain a reference on ifa_maybe once
         * we find one, as we release the IF_ADDR_LOCK() that kept it stable
         * when we move onto the next interface.
         */
        IFNET_RLOCK_NOSLEEP();
        TAILQ_FOREACH(ifp, &V_ifnet, if_link) {
                IF_ADDR_LOCK(ifp);
                TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                        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)) {
                                        ifa_ref(ifa);
                                        IF_ADDR_UNLOCK(ifp);
                                        goto done;
                                }
                        } else {
                                /*
                                 * if we have a special address handler,
                                 * then use it instead of the generic one.
                                 */
                                if (ifa->ifa_claim_addr) {
                                        if ((*ifa->ifa_claim_addr)(ifa, addr)) {
                                                ifa_ref(ifa);
                                                IF_ADDR_UNLOCK(ifp);
                                                goto done;
                                        }
                                        continue;
                                }

                                /*
                                 * 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) then remember the new one
                                 * before continuing to search
                                 * for an even better one.
                                 */
                                if (ifa_maybe == NULL ||
                                    rn_refines((caddr_t)ifa->ifa_netmask,
                                    (caddr_t)ifa_maybe->ifa_netmask)) {
                                        if (ifa_maybe != NULL)
                                                ifa_free(ifa_maybe);
                                        ifa_maybe = ifa;
                                        ifa_ref(ifa_maybe);
                                }
                        }
                }
                IF_ADDR_UNLOCK(ifp);
        }
        ifa = ifa_maybe;
        ifa_maybe = NULL;
done:
        IFNET_RUNLOCK_NOSLEEP();
        if (ifa_maybe != NULL)
                ifa_free(ifa_maybe);
        return (ifa);
}

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

        if (af >= AF_MAX)
                return (NULL);
        IF_ADDR_LOCK(ifp);
        TAILQ_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:
        if (ifa != NULL)
                ifa_ref(ifa);
        IF_ADDR_UNLOCK(ifp);
        return (ifa);
}

#include <net/if_llatbl.h>

/*
 * Default action when installing a route with a Link Level gateway.
 * Lookup an appropriate real ifa to point to.
 * This should be moved to /sys/net/link.c eventually.
 */
static void
link_rtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
{
        struct ifaddr *ifa, *oifa;
        struct sockaddr *dst;
        struct ifnet *ifp;

        RT_LOCK_ASSERT(rt);

        if (cmd != RTM_ADD || ((ifa = rt->rt_ifa) == 0) ||
            ((ifp = ifa->ifa_ifp) == 0) || ((dst = rt_key(rt)) == 0))
                return;
        ifa = ifaof_ifpforaddr(dst, ifp);
        if (ifa) {
                oifa = rt->rt_ifa;
                rt->rt_ifa = ifa;
                ifa_free(oifa);
                if (ifa->ifa_rtrequest && ifa->ifa_rtrequest != link_rtrequest)
                        ifa->ifa_rtrequest(cmd, rt, info);
        }
}

/*
 * Mark an interface down and notify protocols of
 * the transition.
 * NOTE: must be called at splnet or eqivalent.
 */
static void
if_unroute(struct ifnet *ifp, int flag, int fam)
{
        struct ifaddr *ifa;

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

        ifp->if_flags &= ~flag;
        getmicrotime(&ifp->if_lastchange);
        TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
                if (fam == PF_UNSPEC || (fam == ifa->ifa_addr->sa_family))
                        pfctlinput(PRC_IFDOWN, ifa->ifa_addr);
        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.
 * NOTE: must be called at splnet or eqivalent.
 */
static void
if_route(struct ifnet *ifp, int flag, int fam)
{
        struct ifaddr *ifa;

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

        ifp->if_flags |= flag;
        getmicrotime(&ifp->if_lastchange);
        TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
                if (fam == PF_UNSPEC || (fam == ifa->ifa_addr->sa_family))
                        pfctlinput(PRC_IFUP, ifa->ifa_addr);
        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 *, int);      /* XXX: private from if_vlan */
void    (*vlan_trunk_cap_p)(struct ifnet *);            /* XXX: private from if_vlan */

/*
 * 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;

        taskqueue_enqueue(taskqueue_swi, &ifp->if_linktask);
}

static void
do_link_state_change(void *arg, int pending)
{
        struct ifnet *ifp = (struct ifnet *)arg;
        int link_state = ifp->if_link_state;
        CURVNET_SET(ifp->if_vnet);

        /* Notify that the link state has changed. */
        rt_ifmsg(ifp);
        if (ifp->if_vlantrunk != NULL)
                (*vlan_link_state_p)(ifp, 0);

        if ((ifp->if_type == IFT_ETHER || ifp->if_type == IFT_L2VLAN) &&
            IFP2AC(ifp)->ac_netgraph != NULL)
                (*ng_ether_link_state_p)(ifp, link_state);
        if (ifp->if_carp)
                (*carp_linkstate_p)(ifp);
        if (ifp->if_bridge) {
                KASSERT(bstp_linkstate_p != NULL,("if_bridge bstp not loaded!"));
                (*bstp_linkstate_p)(ifp, link_state);
        }
        if (ifp->if_lagg) {
                KASSERT(lagg_linkstate_p != NULL,("if_lagg not loaded!"));
                (*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)
                log(LOG_NOTICE, "%s: link state changed to %s\n", ifp->if_xname,
                    (link_state == LINK_STATE_UP) ? "UP" : "DOWN" );
        CURVNET_RESTORE();
}

/*
 * Mark an interface down and notify protocols of
 * the transition.
 * NOTE: must be called at splnet or eqivalent.
 */
void
if_down(struct ifnet *ifp)
{

        if_unroute(ifp, IFF_UP, AF_UNSPEC);
}

/*
 * Mark an interface up and notify protocols of
 * the transition.
 * NOTE: must be called at splnet or eqivalent.
 */
void
if_up(struct ifnet *ifp)
{

        if_route(ifp, IFF_UP, AF_UNSPEC);
}

/*
 * 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) != 0) {
                n = m->m_act;
                m_freem(m);
        }
        ifq->ifq_head = 0;
        ifq->ifq_tail = 0;
        ifq->ifq_len = 0;
        IFQ_UNLOCK(ifq);
}

/*
 * Handle interface watchdog timer routines.  Called
 * from softclock, we decrement timers (if set) and
 * call the appropriate interface routine on expiration.
 *
 * XXXRW: Note that because timeouts run with Giant, if_watchdog() is called
 * holding Giant.
 */
static void
if_slowtimo(void *arg)
{
        VNET_ITERATOR_DECL(vnet_iter);
        struct ifnet *ifp;
        int s = splimp();

        VNET_LIST_RLOCK_NOSLEEP();
        IFNET_RLOCK_NOSLEEP();
        VNET_FOREACH(vnet_iter) {
                CURVNET_SET(vnet_iter);
                TAILQ_FOREACH(ifp, &V_ifnet, if_link) {
                        if (ifp->if_timer == 0 || --ifp->if_timer)
                                continue;
                        if (ifp->if_watchdog)
                                (*ifp->if_watchdog)(ifp);
                }
                CURVNET_RESTORE();
        }
        IFNET_RUNLOCK_NOSLEEP();
        VNET_LIST_RUNLOCK_NOSLEEP();
        splx(s);
        timeout(if_slowtimo, (void *)0, hz / IFNET_SLOWHZ);
}

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

        IFNET_RLOCK_NOSLEEP();
        TAILQ_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);
        IFNET_RUNLOCK_NOSLEEP();
        return (ifp);
}

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

        IFNET_RLOCK_NOSLEEP();
        TAILQ_FOREACH(ifp, &V_ifnet, if_link) {
                if (strncmp(name, ifp->if_xname, IFNAMSIZ) == 0)
                        break;
        }
        IFNET_RUNLOCK_NOSLEEP();
        return (ifp);
}

/*
 * Hardware specific interface ioctls.
 */
static int
ifhwioctl(u_long cmd, struct ifnet *ifp, caddr_t data, struct thread *td)
{
        struct ifreq *ifr;
        struct ifstat *ifs;
        int error = 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;

#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:
                ifr->ifr_phys = ifp->if_physical;
                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->ifr_buffer.length < descrlen)
                                ifr->ifr_buffer.buffer = NULL;
                        else
                                error = copyout(ifp->if_description,
                                    ifr->ifr_buffer.buffer, descrlen);
                        ifr->ifr_buffer.length = 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->ifr_buffer.length > ifdescr_maxlen)
                        return (ENAMETOOLONG);
                else if (ifr->ifr_buffer.length == 0)
                        descrbuf = NULL;
                else {
                        descrbuf = malloc(ifr->ifr_buffer.length, M_IFDESCR,
                            M_WAITOK | M_ZERO);
                        error = copyin(ifr->ifr_buffer.buffer, descrbuf,
                            ifr->ifr_buffer.length - 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 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_SMART) {
                        /* Smart drivers twiddle their own routes */
                } else if (ifp->if_flags & IFF_UP &&
                    (new_flags & IFF_UP) == 0) {
                        int s = splimp();
                        if_down(ifp);
                        splx(s);
                } else if (new_flags & IFF_UP &&
                    (ifp->if_flags & IFF_UP) == 0) {
                        int s = splimp();
                        if_up(ifp);
                        splx(s);
                }
                /* 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;
                        log(LOG_INFO, "%s: permanently promiscuous mode %s\n",
                            ifp->if_xname,
                            (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);
                }
                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->ifr_data, new_name, IFNAMSIZ, NULL);
                if (error != 0)
                        return (error);
                if (new_name[0] == '\0')
                        return (EINVAL);
                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);

                log(LOG_INFO, "%s: changing name to '%s'\n",
                    ifp->if_xname, new_name);

                strlcpy(ifp->if_xname, new_name, sizeof(ifp->if_xname));
                ifa = ifp->if_addr;
                IFA_LOCK(ifa);
                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;
                IFA_UNLOCK(ifa);

                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);
                }
                /*
                 * If the link MTU changed, do network layer specific procedure.
                 */
                if (ifp->if_mtu != oldmtu) {
#ifdef INET6
                        nd6_setmtu(ifp);
#endif
                }
                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 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.
                         */
                        IF_ADDR_LOCK(ifp);
                        ifma = if_findmulti(ifp, &ifr->ifr_addr);
                        IF_ADDR_UNLOCK(ifp);
                        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 SIOCSLIFPHYADDR:
        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:
                ifs = (struct ifstat *)data;
                ifs->ascii[0] = '\0';

        case SIOCGIFPSRCADDR:
        case SIOCGIFPDSTADDR:
        case SIOCGLIFPHYADDR:
        case SIOCGIFMEDIA:
        case SIOCGIFGENERIC:
                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);
                EVENTHANDLER_INVOKE(iflladdr_event, ifp);
                break;

        case SIOCAIFGROUP:
        {
                struct ifgroupreq *ifgr = (struct ifgroupreq *)ifr;

                error = priv_check(td, PRIV_NET_ADDIFGROUP);
                if (error)
                        return (error);
                if ((error = if_addgroup(ifp, ifgr->ifgr_group)))
                        return (error);
                break;
        }

        case SIOCGIFGROUP:
                if ((error = if_getgroup((struct ifgroupreq *)ifr, ifp)))
                        return (error);
                break;

        case SIOCDIFGROUP:
        {
                struct ifgroupreq *ifgr = (struct ifgroupreq *)ifr;

                error = priv_check(td, PRIV_NET_DELIFGROUP);
                if (error)
                        return (error);
                if ((error = if_delgroup(ifp, ifgr->ifgr_group)))
                        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

/*
 * Interface ioctls.
 */
int
ifioctl(struct socket *so, u_long cmd, caddr_t data, struct thread *td)
{
        struct ifnet *ifp;
        struct ifreq *ifr;
        int error;
        int oif_flags;

        switch (cmd) {
        case SIOCGIFCONF:
        case OSIOCGIFCONF:
                return (ifconf(cmd, data));

#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);

                        return (ifconf(SIOCGIFCONF, (void *)&ifc));
                }
#endif
        }
        ifr = (struct ifreq *)data;

        switch (cmd) {
#ifdef VIMAGE
        case SIOCSIFRVNET:
                error = priv_check(td, PRIV_NET_SETIFVNET);
                if (error)
                        return (error);
                return (if_vmove_reclaim(td, ifr->ifr_name, ifr->ifr_jid));
#endif
        case SIOCIFCREATE:
        case SIOCIFCREATE2:
                error = priv_check(td, PRIV_NET_IFCREATE);
                if (error)
                        return (error);
                return (if_clone_create(ifr->ifr_name, sizeof(ifr->ifr_name),
                        cmd == SIOCIFCREATE2 ? ifr->ifr_data : NULL));
        case SIOCIFDESTROY:
                error = priv_check(td, PRIV_NET_IFDESTROY);
                if (error)
                        return (error);
                return if_clone_destroy(ifr->ifr_name);

        case SIOCIFGCLONERS:
                return (if_clone_list((struct if_clonereq *)data));
        case SIOCGIFGMEMB:
                return (if_getgroupmembers((struct ifgroupreq *)data));
        }

        ifp = ifunit_ref(ifr->ifr_name);
        if (ifp == NULL)
                return (ENXIO);

        error = ifhwioctl(cmd, ifp, data, td);
        if (error != ENOIOCTL) {
                if_rele(ifp);
                return (error);
        }

        oif_flags = ifp->if_flags;
        if (so->so_proto == NULL) {
                if_rele(ifp);
                return (EOPNOTSUPP);
        }
#ifndef COMPAT_43
        error = ((*so->so_proto->pr_usrreqs->pru_control)(so, cmd,
                                                                 data,
                                                                 ifp, td));
        if (error == EOPNOTSUPP && ifp != NULL && ifp->if_ioctl != NULL)
                error = (*ifp->if_ioctl)(ifp, cmd, data);
#else
        {
                u_long ocmd = cmd;

                switch (cmd) {

                case SIOCSIFDSTADDR:
                case SIOCSIFADDR:
                case SIOCSIFBRDADDR:
                case SIOCSIFNETMASK:
#if BYTE_ORDER != BIG_ENDIAN
                        if (ifr->ifr_addr.sa_family == 0 &&
                            ifr->ifr_addr.sa_len < 16) {
                                ifr->ifr_addr.sa_family = ifr->ifr_addr.sa_len;
                                ifr->ifr_addr.sa_len = 16;
                        }
#else
                        if (ifr->ifr_addr.sa_len == 0)
                                ifr->ifr_addr.sa_len = 16;
#endif
                        break;

                case OSIOCGIFADDR:
                        cmd = SIOCGIFADDR;
                        break;

                case OSIOCGIFDSTADDR:
                        cmd = SIOCGIFDSTADDR;
                        break;

                case OSIOCGIFBRDADDR:
                        cmd = SIOCGIFBRDADDR;
                        break;

                case OSIOCGIFNETMASK:
                        cmd = SIOCGIFNETMASK;
                }
                error =  ((*so->so_proto->pr_usrreqs->pru_control)(so,
                                                                   cmd,
                                                                   data,
                                                                   ifp, td));
                if (error == EOPNOTSUPP && ifp != NULL &&
                    ifp->if_ioctl != NULL)
                        error = (*ifp->if_ioctl)(ifp, cmd, data);
                switch (ocmd) {

                case OSIOCGIFADDR:
                case OSIOCGIFDSTADDR:
                case OSIOCGIFBRDADDR:
                case OSIOCGIFNETMASK:
                        *(u_short *)&ifr->ifr_addr = ifr->ifr_addr.sa_family;

                }
        }
#endif /* COMPAT_43 */

        if ((oif_flags ^ ifp->if_flags) & IFF_UP) {
#ifdef INET6
                if (ifp->if_flags & IFF_UP) {
                        int s = splimp();
                        in6_if_up(ifp);
                        splx(s);
                }
#endif
        }
        if_rele(ifp);
        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(LOG_INFO, "%s: promiscuous mode %s\n",
                    ifp->if_xname,
                    (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();
        TAILQ_FOREACH(ifp, &V_ifnet, if_link) {
                int addrs;

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

                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;
                IF_ADDR_LOCK(ifp);
                TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                        struct sockaddr *sa = ifa->ifa_addr;

                        if (prison_if(curthread->td_ucred, sa) != 0)
                                continue;
                        addrs++;
#ifdef COMPAT_43
                        if (cmd == OSIOCGIFCONF) {
                                struct osockaddr *osa =
                                         (struct osockaddr *)&ifr.ifr_addr;
                                ifr.ifr_addr = *sa;
                                osa->sa_family = sa->sa_family;
                                sbuf_bcat(sb, &ifr, sizeof(ifr));
                                max_len += sizeof(ifr);
                        } else
#endif
                        if (sa->sa_len <= sizeof(*sa)) {
                                ifr.ifr_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_overflowed(sb))
                                valid_len = sbuf_len(sb);
                }
                IF_ADDR_UNLOCK(ifp);
                if (addrs == 0) {
                        bzero((caddr_t)&ifr.ifr_addr, sizeof(ifr.ifr_addr));
                        sbuf_bcat(sb, &ifr, sizeof(ifr));
                        max_len += sizeof(ifr);

                        if (!sbuf_overflowed(sb))
                                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, struct sockaddr *sa)
{
        struct ifmultiaddr *ifma;

        IF_ADDR_LOCK_ASSERT(ifp);

        TAILQ_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.
 */
static void
if_freemulti(struct ifmultiaddr *ifma)
{

        KASSERT(ifma->ifma_refcount == 0, ("if_freemulti: refcount %d",
            ifma->ifma_refcount));
        KASSERT(ifma->ifma_protospec == NULL,
            ("if_freemulti: protospec not NULL"));

        if (ifma->ifma_lladdr != NULL)
                free(ifma->ifma_lladdr, M_IFMADDR);
        free(ifma->ifma_addr, M_IFMADDR);
        free(ifma, M_IFMADDR);
}

/*
 * 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;
        int error;

        /*
         * If the address is already present, return a new reference to it;
         * otherwise, allocate storage and set up a new address.
         */
        IF_ADDR_LOCK(ifp);
        ifma = if_findmulti(ifp, sa);
        if (ifma != NULL) {
                ifma->ifma_refcount++;
                if (retifma != NULL)
                        *retifma = ifma;
                IF_ADDR_UNLOCK(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.  If 'llsa' was
         * returned, we will need to free it later.
         */
        llsa = NULL;
        ll_ifma = NULL;
        if (ifp->if_resolvemulti != NULL) {
                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;
                        }
                        TAILQ_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.
         */
        TAILQ_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_UNLOCK(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) {
                (void) (*ifp->if_ioctl)(ifp, SIOCADDMULTI, 0);
        }

        if (llsa != NULL)
                free(llsa, M_IFMADDR);

        return (0);

free_llsa_out:
        if (llsa != NULL)
                free(llsa, M_IFMADDR);

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

/*
 * 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;
#ifdef INVARIANTS
        struct ifnet *oifp;

        IFNET_RLOCK_NOSLEEP();
        TAILQ_FOREACH(oifp, &V_ifnet, if_link)
                if (ifp == oifp)
                        break;
        if (ifp != oifp)
                ifp = NULL;
        IFNET_RUNLOCK_NOSLEEP();

        KASSERT(ifp != NULL, ("%s: ifnet went away", __func__));
#endif
        if (ifp == NULL)
                return (ENOENT);

        IF_ADDR_LOCK(ifp);
        lastref = 0;
        ifma = if_findmulti(ifp, sa);
        if (ifma != NULL)
                lastref = if_delmulti_locked(ifp, ifma, 0);
        IF_ADDR_UNLOCK(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_LOCK(ifp);
        TAILQ_FOREACH_SAFE(ifma, &ifp->if_multiaddrs, ifma_link, next)
                if_delmulti_locked(ifp, ifma, 0);
        IF_ADDR_UNLOCK(ifp);
}

/*
 * 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(struct ifmultiaddr *ifma)
{
        struct ifnet *ifp;
        int lastref;

        ifp = ifma->ifma_ifp;
#ifdef DIAGNOSTIC
        if (ifp == NULL) {
                printf("%s: ifma_ifp seems to be detached\n", __func__);
        } else {
                struct ifnet *oifp;

                IFNET_RLOCK_NOSLEEP();
                TAILQ_FOREACH(oifp, &V_ifnet, if_link)
                        if (ifp == oifp)
                                break;
                if (ifp != oifp) {
                        printf("%s: ifnet %p disappeared\n", __func__, ifp);
                        ifp = NULL;
                }
                IFNET_RUNLOCK_NOSLEEP();
        }
#endif
        /*
         * If and only if the ifnet instance exists: Acquire the address lock.
         */
        if (ifp != NULL)
                IF_ADDR_LOCK(ifp);

        lastref = if_delmulti_locked(ifp, ifma, 0);

        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_UNLOCK(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_LOCK_ASSERT(ifp);
        }

        ifp = ifma->ifma_ifp;

        /*
         * 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 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) {
                                TAILQ_REMOVE(&ifp->if_multiaddrs, ll_ifma,
                                    ifma_link);
                        }
                        if_freemulti(ll_ifma);
                }
        }

        if (ifp != NULL)
                TAILQ_REMOVE(&ifp->if_multiaddrs, ifma, ifma_link);

        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.
 */
int
if_setlladdr(struct ifnet *ifp, const u_char *lladdr, int len)
{
        struct sockaddr_dl *sdl;
        struct ifaddr *ifa;
        struct ifreq ifr;

        IF_ADDR_LOCK(ifp);
        ifa = ifp->if_addr;
        if (ifa == NULL) {
                IF_ADDR_UNLOCK(ifp);
                return (EINVAL);
        }
        ifa_ref(ifa);
        IF_ADDR_UNLOCK(ifp);
        sdl = (struct sockaddr_dl *)ifa->ifa_addr;
        if (sdl == NULL) {
                ifa_free(ifa);
                return (EINVAL);
        }
        if (len != sdl->sdl_alen) {     /* don't allow length to change */
                ifa_free(ifa);
                return (EINVAL);
        }
        switch (ifp->if_type) {
        case IFT_ETHER:
        case IFT_FDDI:
        case IFT_XETHER:
        case IFT_ISO88025:
        case IFT_L2VLAN:
        case IFT_BRIDGE:
        case IFT_ARCNET:
        case IFT_IEEE8023ADLAG:
        case IFT_IEEE80211:
                bcopy(lladdr, LLADDR(sdl), len);
                ifa_free(ifa);
                break;
        default:
                ifa_free(ifa);
                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);
                }
#ifdef INET
                /*
                 * Also send gratuitous ARPs to notify other nodes about
                 * the address change.
                 */
                TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                        if (ifa->ifa_addr->sa_family == AF_INET)
                                arp_ifinit(ifp, ifa);
                }
#endif
        }
        return (0);
}

/*
 * 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, ...)
{
        va_list ap;
        int retval;

        retval = printf("%s: ", ifp->if_xname);
        va_start(ap, fmt);
        retval += vprintf(fmt, ap);
        va_end(ap);
        return (retval);
}

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);
}

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_DROP(ifq);
                IF_UNLOCK(ifq);
                m_freem(m);
                return (0);
        }
        if (ifp != NULL) {
                ifp->if_obytes += m->m_pkthdr.len + adjust;
                if (m->m_flags & (M_BCAST|M_MCAST))
                        ifp->if_omcasts++;
                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));
        if_com_alloc[type] = NULL;
        if_com_free[type] = NULL;
}