xref: /freebsd-9.3-release/sys/net/if.c

/*-
 * 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: head/sys/net/if.c 176906 2008-03-07 16:00:44Z rwatson $
 */

#include "opt_compat.h"
#include "opt_inet6.h"
#include "opt_inet.h"
#include "opt_mac.h"
#include "opt_carp.h"

#include <sys/param.h>
#include <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 <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 <net/if.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>

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

#include <security/mac/mac_framework.h>

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

/* 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");

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);

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 void	if_purgemaddrs(struct ifnet *);
static int	ifconf(u_long, caddr_t);
static void	if_freemulti(struct ifmultiaddr *);
static void	if_grow(void);
static void	if_init(void *);
static void	if_check(void *);
static void	if_qflush(struct ifaltq *);
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 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	if_start_deferred(void *context, int pending);
static void	do_link_state_change(void *, int);
static int	if_getgroup(struct ifgroupreq *, struct ifnet *);
static int	if_getgroupmembers(struct ifgroupreq *);
#ifdef INET6
/*
 * XXX: declare here to avoid to include many inet6 related files..
 * should be more generalized?
 */
extern void	nd6_setmtu(struct ifnet *);
#endif

int	if_index = 0;
struct	ifindex_entry *ifindex_table = NULL;
int	ifqmaxlen = IFQ_MAXLEN;
struct	ifnethead ifnet;	/* depend on static init XXX */
struct	ifgrouphead ifg_head;
struct	mtx ifnet_lock;
static	if_com_alloc_t *if_com_alloc[256];
static	if_com_free_t *if_com_free[256];

static int	if_indexlim = 8;
static struct	knlist ifklist;

static void	filt_netdetach(struct knote *kn);
static int	filt_netdev(struct knote *kn, long hint);

static struct filterops netdev_filtops =
    { 1, NULL, filt_netdetach, filt_netdev };

/*
 * System initialization
 */
SYSINIT(interfaces, SI_SUB_INIT_IF, SI_ORDER_FIRST, if_init, NULL)
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");

static d_open_t		netopen;
static d_close_t	netclose;
static d_ioctl_t	netioctl;
static d_kqfilter_t	netkqfilter;

static struct cdevsw net_cdevsw = {
	.d_version =	D_VERSION,
	.d_flags =	D_NEEDGIANT,
	.d_open =	netopen,
	.d_close =	netclose,
	.d_ioctl =	netioctl,
	.d_name =	"net",
	.d_kqfilter =	netkqfilter,
};

static int
netopen(struct cdev *dev, int flag, int mode, struct thread *td)
{
	return (0);
}

static int
netclose(struct cdev *dev, int flags, int fmt, struct thread *td)
{
	return (0);
}

static int
netioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag, struct thread *td)
{
	struct ifnet *ifp;
	int error, idx;

	/* only support interface specific ioctls */
	if (IOCGROUP(cmd) != 'i')
		return (EOPNOTSUPP);
	idx = minor(dev);
	if (idx == 0) {
		/*
		 * special network device, not interface.
		 */
		if (cmd == SIOCGIFCONF)
			return (ifconf(cmd, data));	/* XXX remove cmd */
#ifdef __amd64__
		if (cmd == SIOCGIFCONF32)
			return (ifconf(cmd, data));	/* XXX remove cmd */
#endif
		return (EOPNOTSUPP);
	}

	ifp = ifnet_byindex(idx);
	if (ifp == NULL)
		return (ENXIO);

	error = ifhwioctl(cmd, ifp, data, td);
	if (error == ENOIOCTL)
		error = EOPNOTSUPP;
	return (error);
}

static int
netkqfilter(struct cdev *dev, struct knote *kn)
{
	struct knlist *klist;
	struct ifnet *ifp;
	int idx;

	switch (kn->kn_filter) {
	case EVFILT_NETDEV:
		kn->kn_fop = &netdev_filtops;
		break;
	default:
		return (EINVAL);
	}

	idx = minor(dev);
	if (idx == 0) {
		klist = &ifklist;
	} else {
		ifp = ifnet_byindex(idx);
		if (ifp == NULL)
			return (1);
		klist = &ifp->if_klist;
	}

	kn->kn_hook = (caddr_t)klist;

	knlist_add(klist, kn, 0);

	return (0);
}

static void
filt_netdetach(struct knote *kn)
{
	struct knlist *klist = (struct knlist *)kn->kn_hook;

	knlist_remove(klist, kn, 0);
}

static int
filt_netdev(struct knote *kn, long hint)
{
	struct knlist *klist = (struct knlist *)kn->kn_hook;

	/*
	 * Currently NOTE_EXIT is abused to indicate device detach.
	 */
	if (hint == NOTE_EXIT) {
		kn->kn_data = NOTE_LINKINV;
		kn->kn_flags |= (EV_EOF | EV_ONESHOT);
		knlist_remove_inevent(klist, kn);
		return (1);
	}
	if (hint != 0)
		kn->kn_data = hint;			/* current status */
	if (kn->kn_sfflags & hint)
		kn->kn_fflags |= hint;
	return (kn->kn_fflags != 0);
}

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

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

	IFNET_LOCK_INIT();
	TAILQ_INIT(&ifnet);
	TAILQ_INIT(&ifg_head);
	knlist_init(&ifklist, NULL, NULL, NULL, NULL);
	if_grow();				/* create initial table */
	ifdev_byindex(0) = make_dev(&net_cdevsw, 0,
	    UID_ROOT, GID_WHEEL, 0600, "network");
	if_clone_init();
}

static void
if_grow(void)
{
	u_int n;
	struct ifindex_entry *e;

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

/* ARGSUSED*/
static void
if_check(void *dummy __unused)
{
	struct ifnet *ifp;
	int s;

	s = splimp();
	IFNET_RLOCK();	/* could sleep on rare error; mostly okay XXX */
	TAILQ_FOREACH(ifp, &ifnet, if_link) {
		if (ifp->if_snd.ifq_maxlen == 0) {
			if_printf(ifp, "XXX: driver didn't set ifq_maxlen\n");
			ifp->if_snd.ifq_maxlen = ifqmaxlen;
		}
		if (!mtx_initialized(&ifp->if_snd.ifq_mtx)) {
			if_printf(ifp,
			    "XXX: driver didn't initialize queue mtx\n");
			mtx_init(&ifp->if_snd.ifq_mtx, "unknown",
			    MTX_NETWORK_LOCK, MTX_DEF);
		}
	}
	IFNET_RUNLOCK();
	splx(s);
	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;

	ifp = malloc(sizeof(struct ifnet), M_IFNET, M_WAITOK|M_ZERO);

	/*
	 * Try to find an empty slot below if_index.  If we fail, take
	 * the next slot.
	 *
	 * XXX: should be locked!
	 */
	for (ifp->if_index = 1; ifp->if_index <= if_index; ifp->if_index++) {
		if (ifnet_byindex(ifp->if_index) == NULL)
			break;
	}
	/* Catch if_index overflow. */
	if (ifp->if_index < 1) {
		free(ifp, M_IFNET);
		return (NULL);
	}
	if (ifp->if_index > if_index)
		if_index = ifp->if_index;
	if (if_index >= if_indexlim)
		if_grow();
	ifnet_byindex(ifp->if_index) = ifp;

	ifp->if_type = 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);
			return (NULL);
		}
	}
	IF_ADDR_LOCK_INIT(ifp);

	return (ifp);
}

/*
 * Free the struct ifnet, the associated index, and the layer 2 common
 * structure if needed.  All the work is done in if_free_type().
 *
 * Do not add code to this function!  Add it to if_free_type().
 */
void
if_free(struct ifnet *ifp)
{

	if_free_type(ifp, ifp->if_type);
}

/*
 * Do the actual work of freeing a struct ifnet, associated index, and
 * layer 2 common structure.  This version should only be called by
 * intefaces that switch their type after calling if_alloc().
 */
void
if_free_type(struct ifnet *ifp, u_char type)
{

	if (ifp != ifnet_byindex(ifp->if_index)) {
		if_printf(ifp, "%s: value was not if_alloced, skipping\n",
		    __func__);
		return;
	}

	IF_ADDR_LOCK_DESTROY(ifp);

	ifnet_byindex(ifp->if_index) = NULL;

	/* XXX: should be locked with if_findindex() */
	while (if_index > 0 && ifnet_byindex(if_index) == NULL)
		if_index--;

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

	free(ifp, M_IFNET);
};

/*
 * Perform generic interface initalization tasks and attach the interface
 * to the list of "active" interfaces.
 *
 * XXX:
 *  - The decision to return void and thus require this function to
 *    succeed is questionable.
 *  - We do more initialization here then is probably a good idea.
 *    Some of this should probably move to if_alloc().
 *  - 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)
{
	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);

	TASK_INIT(&ifp->if_starttask, 0, if_start_deferred, ifp);
	TASK_INIT(&ifp->if_linktask, 0, do_link_state_change, ifp);
	IF_AFDATA_LOCK_INIT(ifp);
	ifp->if_afdata_initialized = 0;

	TAILQ_INIT(&ifp->if_addrhead);
	TAILQ_INIT(&ifp->if_prefixhead);
	TAILQ_INIT(&ifp->if_multiaddrs);
	TAILQ_INIT(&ifp->if_groups);

	if_addgroup(ifp, IFG_ALL);

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

#ifdef MAC
	mac_ifnet_init(ifp);
	mac_ifnet_create(ifp);
#endif

	ifdev_byindex(ifp->if_index) = make_dev(&net_cdevsw,
	    unit2minor(ifp->if_index),
	    UID_ROOT, GID_WHEEL, 0600, "%s/%s",
	    net_cdevsw.d_name, ifp->if_xname);
	make_dev_alias(ifdev_byindex(ifp->if_index), "%s%d",
	    net_cdevsw.d_name, ifp->if_index);

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

	/*
	 * 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_LOCK_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;
	ifa->ifa_refcnt = 1;
	TAILQ_INSERT_HEAD(&ifp->if_addrhead, ifa, ifa_link);
	ifp->if_broadcastaddr = NULL; /* reliably crash if used uninitialized */
	ifp->if_snd.altq_type = 0;
	ifp->if_snd.altq_disc = NULL;
	ifp->if_snd.altq_flags &= ALTQF_CANTCHANGE;
	ifp->if_snd.altq_tbr  = NULL;
	ifp->if_snd.altq_ifp  = ifp;

	IFNET_WLOCK();
	TAILQ_INSERT_TAIL(&ifnet, ifp, if_link);
	IFNET_WUNLOCK();

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

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

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

	if (ifp->if_watchdog != NULL)
		if_printf(ifp,
		    "WARNING: using obsoleted if_watchdog interface\n");
	if (ifp->if_flags & IFF_NEEDSGIANT)
		if_printf(ifp,
		    "WARNING: using obsoleted IFF_NEEDSGIANT flag\n");
}

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

	s = splnet();
	TAILQ_FOREACH(ifp, &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);
		IFAFREE(ifa);
	}
}

/*
 * Remove any multicast network addresses from an interface.
 */
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.
 *
 * 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)
{
	struct ifaddr *ifa;
	struct radix_node_head	*rnh;
	int s;
	int i;
	struct domain *dp;
 	struct ifnet *iter;
 	int found = 0;

	IFNET_WLOCK();
	TAILQ_FOREACH(iter, &ifnet, if_link)
		if (iter == ifp) {
			TAILQ_REMOVE(&ifnet, ifp, if_link);
			found = 1;
			break;
		}
	IFNET_WUNLOCK();
	if (!found)
		return;

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

	/*
	 * Remove routes and flush queues.
	 */
	s = splnet();
	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);

	/*
	 * Remove link ifaddr pointer and maybe decrement if_index.
	 * Clean up all addresses.
	 */
	ifp->if_addr = NULL;
	destroy_dev(ifdev_byindex(ifp->if_index));
	ifdev_byindex(ifp->if_index) = 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);
		IFAFREE(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++) {
		if ((rnh = rt_tables[i]) == 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);
	devctl_notify("IFNET", ifp->if_xname, "DETACH", NULL);

	IF_AFDATA_LOCK(ifp);
	for (dp = domains; 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]);
	}
	IF_AFDATA_UNLOCK(ifp);

#ifdef MAC
	mac_ifnet_destroy(ifp);
#endif /* MAC */
	KNOTE_UNLOCKED(&ifp->if_klist, NOTE_EXIT);
	knlist_clear(&ifp->if_klist, 0);
	knlist_destroy(&ifp->if_klist);
	mtx_destroy(&ifp->if_snd.ifq_mtx);
	IF_AFDATA_DESTROY(ifp);
	splx(s);
}

/*
 * 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, &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(&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(&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);
}

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

	return (0);
}

/*
 * 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*/
struct ifaddr *
ifa_ifwithaddr(struct sockaddr *addr)
{
	struct ifnet *ifp;
	struct ifaddr *ifa;

	IFNET_RLOCK();
	TAILQ_FOREACH(ifp, &ifnet, if_link)
		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))
				goto done;
			/* IP6 doesn't have broadcast */
			if ((ifp->if_flags & IFF_BROADCAST) &&
			    ifa->ifa_broadaddr &&
			    ifa->ifa_broadaddr->sa_len != 0 &&
			    sa_equal(ifa->ifa_broadaddr, addr))
				goto done;
		}
	ifa = NULL;
done:
	IFNET_RUNLOCK();
	return (ifa);
}

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

	IFNET_RLOCK();
	TAILQ_FOREACH(ifp, &ifnet, if_link)
		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))
				goto done;
		}
	ifa = NULL;
done:
	IFNET_RUNLOCK();
	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();
	TAILQ_FOREACH(ifp, &ifnet, if_link) {
		if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
			continue;
		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
			if (ifa->ifa_addr->sa_family != addr->sa_family)
				continue;
			if (ifa->ifa_dstaddr &&
			    sa_equal(addr, ifa->ifa_dstaddr))
				goto done;
		}
	}
	ifa = NULL;
done:
	IFNET_RUNLOCK();
	return (ifa);
}

/*
 * Find an interface on a specific network.  If many, choice
 * is most specific found.
 */
struct ifaddr *
ifa_ifwithnet(struct sockaddr *addr)
{
	struct ifnet *ifp;
	struct ifaddr *ifa;
	struct ifaddr *ifa_maybe = (struct ifaddr *) 0;
	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 <= if_index)
		return (ifaddr_byindex(sdl->sdl_index));
	}

	/*
	 * Scan though each interface, looking for ones that have
	 * addresses in this address family.
	 */
	IFNET_RLOCK();
	TAILQ_FOREACH(ifp, &ifnet, if_link) {
		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) {
				/*
				 * 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 != 0 &&
				    sa_equal(addr, ifa->ifa_dstaddr))
					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))
						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 == 0 ||
				    rn_refines((caddr_t)ifa->ifa_netmask,
				    (caddr_t)ifa_maybe->ifa_netmask))
					ifa_maybe = ifa;
			}
		}
	}
	ifa = ifa_maybe;
done:
	IFNET_RUNLOCK();
	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 = 0;
	u_int af = addr->sa_family;

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

#include <net/route.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) {
		IFAREF(ifa);		/* XXX */
		oifa = rt->rt_ifa;
		rt->rt_ifa = ifa;
		IFAFREE(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);
	if_qflush(&ifp->if_snd);
#ifdef DEV_CARP
	if (ifp->if_carp)
		carp_carpdev_state(ifp->if_carp);
#endif
	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);
#ifdef DEV_CARP
	if (ifp->if_carp)
		carp_carpdev_state(ifp->if_carp);
#endif
	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;
	int link;

	/* Notify that the link state has changed. */
	rt_ifmsg(ifp);
	if (link_state == LINK_STATE_UP)
		link = NOTE_LINKUP;
	else if (link_state == LINK_STATE_DOWN)
		link = NOTE_LINKDOWN;
	else
		link = NOTE_LINKINV;
	KNOTE_UNLOCKED(&ifp->if_klist, link);
	if (ifp->if_vlantrunk != NULL)
		(*vlan_link_state_p)(ifp, link);

	if ((ifp->if_type == IFT_ETHER || ifp->if_type == IFT_L2VLAN) &&
	    IFP2AC(ifp)->ac_netgraph != NULL)
		(*ng_ether_link_state_p)(ifp, link_state);
#ifdef DEV_CARP
	if (ifp->if_carp)
		carp_carpdev_state(ifp->if_carp);
#endif
	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);
	}

	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" );
}

/*
 * 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.
 */
static void
if_qflush(struct ifaltq *ifq)
{
	struct mbuf *m, *n;

	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.  If we switch to an MPSAFE callout, we likely need to grab
 * Giant before entering if_watchdog() on an IFF_NEEDSGIANT interface.
 */
static void
if_slowtimo(void *arg)
{
	struct ifnet *ifp;
	int s = splimp();

	IFNET_RLOCK();
	TAILQ_FOREACH(ifp, &ifnet, if_link) {
		if (ifp->if_timer == 0 || --ifp->if_timer)
			continue;
		if (ifp->if_watchdog)
			(*ifp->if_watchdog)(ifp);
	}
	IFNET_RUNLOCK();
	splx(s);
	timeout(if_slowtimo, (void *)0, hz / IFNET_SLOWHZ);
}

/*
 * Map interface name to
 * interface structure pointer.
 */
struct ifnet *
ifunit(const char *name)
{
	struct ifnet *ifp;

	IFNET_RLOCK();
	TAILQ_FOREACH(ifp, &ifnet, if_link) {
		if (strncmp(name, ifp->if_xname, IFNAMSIZ) == 0)
			break;
	}
	IFNET_RUNLOCK();
	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;
	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 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) {
			IFF_LOCKGIANT(ifp);
			(void) (*ifp->if_ioctl)(ifp, cmd, data);
			IFF_UNLOCKGIANT(ifp);
		}
		getmicrotime(&ifp->if_lastchange);
		break;

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

		/* 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);
		break;

	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);
		IFF_LOCKGIANT(ifp);
		error = (*ifp->if_ioctl)(ifp, cmd, data);
		IFF_UNLOCKGIANT(ifp);
		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);
		IFF_LOCKGIANT(ifp);
		error = (*ifp->if_ioctl)(ifp, cmd, data);
		IFF_UNLOCKGIANT(ifp);
		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);
		IFF_LOCKGIANT(ifp);
		error = (*ifp->if_ioctl)(ifp, cmd, data);
		IFF_UNLOCKGIANT(ifp);
		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);
		IFF_LOCKGIANT(ifp);
		error = (*ifp->if_ioctl)(ifp, cmd, data);
		IFF_UNLOCKGIANT(ifp);
		break;

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

	case 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);
}

/*
 * 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:
#ifdef __amd64__
	case SIOCGIFCONF32:
#endif
		return (ifconf(cmd, data));
	}
	ifr = (struct ifreq *)data;

	switch (cmd) {
	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(ifr->ifr_name);
	if (ifp == 0)
		return (ENXIO);

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

	oif_flags = ifp->if_flags;
	if (so->so_proto == 0)
		return (EOPNOTSUPP);
#ifndef COMPAT_43
	error = ((*so->so_proto->pr_usrreqs->pru_control)(so, cmd,
								 data,
								 ifp, td));
#else
	{
		int 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));
		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
		DELAY(100);/* XXX: temporary workaround for fxp issue*/
		if (ifp->if_flags & IFF_UP) {
			int s = splimp();
			in6_if_up(ifp);
			splx(s);
		}
#endif
	}
	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;
	IFF_LOCKGIANT(ifp);
	error = (*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, (caddr_t)&ifr);
	IFF_UNLOCKGIANT(ifp);
	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;
#ifdef __amd64__
	struct ifconf32 *ifc32 = (struct ifconf32 *)data;
	struct ifconf ifc_swab;
#endif
	struct ifnet *ifp;
	struct ifaddr *ifa;
	struct ifreq ifr;
	struct sbuf *sb;
	int error, full = 0, valid_len, max_len;

#ifdef __amd64__
	if (cmd == SIOCGIFCONF32) {
		ifc_swab.ifc_len = ifc32->ifc_len;
		ifc_swab.ifc_buf = (caddr_t)(uintptr_t)ifc32->ifc_buf;
		ifc = &ifc_swab;
	}
#endif
	/* 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();		/* could sleep XXX */
	TAILQ_FOREACH(ifp, &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;
		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
			struct sockaddr *sa = ifa->ifa_addr;

			if (jailed(curthread->td_ucred) &&
			    prison_if(curthread->td_ucred, sa))
				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 (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;
#ifdef __amd64__
	if (cmd == SIOCGIFCONF32)
		ifc32->ifc_len = valid_len;
#endif
	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;

	MALLOC(ifma, struct ifmultiaddr *, sizeof *ifma, M_IFMADDR, mflags |
	    M_ZERO);
	if (ifma == NULL)
		return (NULL);

	MALLOC(dupsa, struct sockaddr *, 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);
	}

	MALLOC(dupsa, struct sockaddr *, 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) {
		IFF_LOCKGIANT(ifp);
		(void) (*ifp->if_ioctl)(ifp, SIOCADDMULTI, 0);
		IFF_UNLOCKGIANT(ifp);
	}

	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();
	TAILQ_FOREACH(oifp, &ifnet, if_link)
		if (ifp == oifp)
			break;
	if (ifp != oifp)
		ifp = NULL;
	IFNET_RUNLOCK();

	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) {
		IFF_LOCKGIANT(ifp);
		(void)(*ifp->if_ioctl)(ifp, SIOCDELMULTI, 0);
		IFF_UNLOCKGIANT(ifp);
	}

	return (0);
}

/*
 * Delete a multicast group membership by group membership pointer.
 * Network-layer protocol domains must use this routine.
 *
 * It is safe to call this routine if the ifp disappeared. Callers should
 * hold IFF_LOCKGIANT() to avoid a LOR in case the hardware needs to be
 * reconfigured.
 */
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();
		TAILQ_FOREACH(oifp, &ifnet, if_link)
			if (ifp == oifp)
				break;
		if (ifp != oifp) {
			printf("%s: ifnet %p disappeared\n", __func__, ifp);
			ifp = NULL;
		}
		IFNET_RUNLOCK();
	}
#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) {
			IFF_LOCKGIANT(ifp);
			(void)(*ifp->if_ioctl)(ifp, SIOCDELMULTI, 0);
			IFF_UNLOCKGIANT(ifp);
		}
	}
}

/*
 * 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;

	ifa = ifp->if_addr;
	if (ifa == NULL)
		return (EINVAL);
	sdl = (struct sockaddr_dl *)ifa->ifa_addr;
	if (sdl == NULL)
		return (EINVAL);
	if (len != sdl->sdl_alen)	/* don't allow length to change */
		return (EINVAL);
	switch (ifp->if_type) {
	case IFT_ETHER:
	case IFT_FDDI:
	case IFT_XETHER:
	case IFT_ISO88025:
	case IFT_L2VLAN:
	case IFT_BRIDGE:
	case IFT_ARCNET:
	case IFT_IEEE8023ADLAG:
		bcopy(lladdr, LLADDR(sdl), len);
		break;
	default:
		return (ENODEV);
	}
	/*
	 * If the interface is already up, we need
	 * to re-init it in order to reprogram its
	 * address filter.
	 */
	if ((ifp->if_flags & IFF_UP) != 0) {
		if (ifp->if_ioctl) {
			IFF_LOCKGIANT(ifp);
			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);
			IFF_UNLOCKGIANT(ifp);
		}
#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);
}

/*
 * When an interface is marked IFF_NEEDSGIANT, its if_start() routine cannot
 * be called without Giant.  However, we often can't acquire the Giant lock
 * at those points; instead, we run it via a task queue that holds Giant via
 * if_start_deferred.
 *
 * XXXRW: We need to make sure that the ifnet isn't fully detached until any
 * outstanding if_start_deferred() tasks that will run after the free.  This
 * probably means waiting in if_detach().
 */
void
if_start(struct ifnet *ifp)
{

	if (ifp->if_flags & IFF_NEEDSGIANT) {
		if (mtx_owned(&Giant))
			(*(ifp)->if_start)(ifp);
		else
			taskqueue_enqueue(taskqueue_swi_giant,
			    &ifp->if_starttask);
	} else
		(*(ifp)->if_start)(ifp);
}

static void
if_start_deferred(void *context, int pending)
{
	struct ifnet *ifp;

	GIANT_REQUIRED;

	ifp = context;
	(ifp->if_start)(ifp);
}

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)
		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;
}